METHOD FOR TESTING AN INJECTOR VALVE

TECHNICAL FIELD

The disclosure relates to a method for testing an injector valve for liquid gas, such as liquefied petroleum gas, LGP.

BACKGROUND

WO 2016/155746 discloses a method for testing an injector valve for liquid gas such as methanol. The injector valve may be used for a two-stroke combustion engine. The injector valve is supplied with sealing oil and control oil for controlling the supply of liquid gas. The disclosed injector valve holds a plunger piston chamber for forming a compression chamber, a suction valve with a suction piston and a nozzle valve with a nozzle piston, one or more nozzle openings, and a control oil channel, wherein the fuel fluid channels provide a fluid connection from the plunger piston chamber to the nozzle openings when the suction valve is open by a pressure on the suction piston provided by a fluid pressure in the plunger piston chamber and when the nozzle valve is open by a pressure on the nozzle piston provided by a control oil pressure supplied via the control oil channel. For the test disclosed in WO 2016/155746, the injector valve is placed in a holder and the top cover is removed and substituted with a connecting piece and the pressure of the control oil is increased until the opening pressure for the nozzle valve is reached and the injector valve sprays oil from the nozzle openings into a spray chamber. As a result, the opening pressure of the nozzle valve can be checked. However, there is no disclosure of a leakage test of the suction valve.

DK 202070137 A1 and WO 2021/043380 disclose a method for testing a valve body of an injector valve for liquid gas, and a method for testing the assembled injector valve. The injector valve may be used as a fuel booster injection valve for the liquefied petroleum gas, LGP, and may be designed for performing two functions: to pressurize or boost the LPG to the desired injection pressure, and to ensure the correct timing and duration of the LPG injection. During normal operation, the injector valve is supplied with sealing oil, plunge oil, control oil, and liquid petroleum gas, LPG, as fuel. Sealing oil is to prevent internal leak of liquid gas from entering unintended areas of the injector valve. Plunge oil is to pressurize the fuel, LPG. Control oil is to control the timing of opening the injector valve for delivering compressed fuel gas to the combustion chamber. Liquid fuel is supplied to the injector valve constantly.

The valve body of the valve disclosed in DK 202070137 A1 and WO 2021/043390 holds a plunger piston chamber for forming a compression chamber, a suction valve with a suction piston, one or more fuel fluid channels, a nozzle valve with a nozzle piston, one or more nozzle openings, and a control oil channel, wherein the fuel fluid channels provide a fluid connection from the plunger piston chamber to the nozzle openings when the suction valve is open by a pressure on the suction piston provided by a fluid pressure in the plunger piston chamber and when the nozzle valve is open by a pressure on the nozzle piston provided by a control oil pressure supplied via the control oil channel. The test of the valve body includes a test for verifying that the suction valve is tight, and a test for testing that the nozzle valve is tight.

A new injector valve for LPG for a two-stroke combustion engine has been developed by MAN Energy Solutions. This injector valve is also supplied with sealing oil and control oil for controlling the supply of liquid gas. Leaks if any could be very dangerous.

Thus, there is also a need for an improved method for testing this new injector valve for leaks, and there is also a need for an improved working test of this injector valve.

SUMMARY

It is an object of the present disclosure to provide an improved method for testing an injector valve for valve leaks.

This object is achieved in accordance with a first aspect by providing a method of testing an injector valve (44) for a combustion engine, which injector valve (44) comprises: a plunger piston sealing chamber (136) with a plunger piston (58) for forming a plunger compression chamber (74), said plunger piston (58) being provided with a plunger piston fuel oil opening (57b) at the bottom and said plunger piston (58) being controlled by supply of plunger oil at a plunger oil pressure via a cover plunger oil supply channel (63); a suction one-way valve (70) for fuel oil inlet via a suction valve fuel inlet (72), a plunger chamber supply channel (73) for supply of fuel oil from the suction one-way valve (70) to the plunger compression chamber (74) or to the plunger piston fuel oil opening (57b); a non-return valve (77) in fluid connection with the plunger compression chamber (74) or the plunger piston fuel oil opening (57b) via a non-return valve supply channel (75) for supply of fuel oil to the non-return valve (77); a nozzle valve (61a) with a nozzle valve chamber (81), a nozzle valve piston cutoff shaft (62), a nozzle valve spring (96), a nozzle valve connection seat (88), and a nozzle valve opening (61 b), said nozzle valve piston cut-off shaft (62) having a nozzle valve piston cut-off shaft tip (61c) protruding through the opening (61b) of the nozzle valve (61a); and a number of nozzle valve chamber supply channels (78a, 78b, 79a, 79b, 80a, 80b) providing a fluid connection from the non-return valve (77) to the nozzle valve chamber (81) for supply of fuel oil from the plunger compression chamber (74) or from the plunger piston fuel oil opening (57b) via the non-return valve (77) to the nozzle valve chamber (81); said method comprising:

(a) applying a predetermined lifting pressure to the nozzle valve piston cut-off shaft tip (61c) protruding through the opening (61 b) of the nozzle valve (61a), said lifting pressure being higher than a spring force exerted by the nozzle valve spring (96) on the nozzle valve piston cut-off shaft (62) to thereby maintain the nozzle valve piston cut-off shaft (62) in a lifted position from the nozzle valve connection seat (88) in which the nozzle valve (61a) is open;

(b) supplying plunger oil to the plunger piston (58) via the cover plunger oil supply channel (63) at a first test plunger oil pressure, said first test plunger oil pressure being equal to or larger than a predetermined plunger oil pressure required for maintaining the plunger piston (58) at the bottom of the plunger piston sealing chamber (136) to thereby close the plunger compression chamber (74) while maintaining a fluid connection from the plunger chamber supply channel (73) via the plunger piston fuel oil opening (57b) to the non-return valve supply channel (75); (c) supplying fuel oil at a first predetermined test fuel oil pressure to the suction valve fuel inlet (72), via the suction one-way valve (70) and the piston fuel oil opening (57b) to the non-return valve supply channel (75), said first predetermined test fuel oil pressure being lower than a predetermined fuel oil pressure required for opening the non-return valve (77); and

(d) checking whether any of the supplied fuel oil reaches out from the nozzle valve opening (61 b).

If the non-return valve 77 is tight, no oil should be observed reaching out from the nozzle valve opening 61 b.

In a possible implementation form of the first aspect, the injector valve (44) before being tested is in an assembled condition with an atomizer (43) provided at a bottom of the valve (44) with the nozzle valve piston cut-off shaft tip (61c) protruding into the atomizer (43) for output of fuel from the nozzle valve opening (61 b) through the atomizer (43), and the atomizer (43) is removed when testing the injector valve (44).

In a possible implementation form of the first aspect, the injector valve under test (44) further comprises a hydraulic piston chamber (155) holding a hydraulic piston (64) connected to the nozzle valve piston cut-off shaft (62), said hydraulic piston (64) being controlled by supply of control oil at a control oil pressure via control oil supply channels (141 , 142) for opening and closing the nozzle valve (61a).

In a possible implementation form of the first aspect, the injector valve under test (44) further comprises sealing oil channels (131 , 132, 133, 134) in fluid connection with the plunger piston sealing chamber (136) for sealing the plunger piston (58), and in fluid connection with the hydraulic piston chamber (155) for sealing the hydraulic piston (64); and the method before the supply of plunger oil at step (b) comprises a sealing step by supplying sealing oil at a first sealing oil pressure to the plunger piston sealing chamber (136) and the hydraulic piston chamber (155) via the sealing oil channels (131 , 132, 133, 135), said first sealing oil pressure being higher than or equal to a predetermined sealing oil pressure required for sealing of the plunger piston (58) within the plunger piston sealing chamber (23) and for sealing of the hydraulic piston (64) within the hydraulic piston chamber (155).

In a possible implementation form of the first aspect, the predetermined sealing oil pressure is in the range of 60-100 bar, such as in the range of 70-90 bar, such as around 80 bar.

In a possible implementation form of the first aspect, the valve (44) being tested is placed in a function test valve holder (45) holding a nozzle valve piston lifting unit (46b) with a lifting piston (67) and lifting oil channels (66), said nozzle valve piston lifting unit (46b) being positioned with the lifting piston (67) engaging the nozzle valve piston cut-off shaft tip (61 b), and lifting oil is supplied at a predetermined pressure to the lifting piston (67) via the lifting oil channels (68) to thereby provide said predetermined lifting pressure for maintaining the nozzle valve piston cut-off shaft (62) in the lifted position.

In a possible implementation form of the first aspect, the nozzle valve piston lifting unit (46b) further has lifting unit fuel oil leakage channels (83, 84) and a lifting unit fuel oil outlet (85) in fluid connection with the nozzle valve opening (61 b), whereby any fuel oil reaching out from the nozzle valve opening (61 b) will reach out from the lifting unit fuel oil outlet (85).

In a possible implementation form of the first aspect, the lifting unit fuel oil outlet (85) faces an oil injector chamber (59) for collection of oil leaking or reaching out from the lifting unit fuel oil outlet (85).

In a possible implementation form of the first aspect, the first test plunger oil pressure is in the range of 280-320 bar, such as about 300 bar.

In a possible implementation form of the first aspect, the step of supplying plunger oil to the plunger piston (58) at step (b) comprises a first step of slowly increasing the pressure of supplied plunger oil to a first lower initial oil pressure and then proceed by increasing the oil pressure to the first test plunger oil pressure. In a possible implementation form of the first aspect, the first lower initial oil pressure is in the range of 10 to 50 bar.

In a possible implementation form of the first aspect, the first predetermined test fuel oil pressure of step (c) is about 30 bar.

In a possible implementation form of the first aspect, the non-return valve (77) comprises a non-return valve housing (87a), a non-return valve spindle (86), a non-return valve connection seat (76) and a non-return valve spring (87b) for forcing the non-return valve spindle (86) against the non-return valve connection seat (76) to thereby close the nonreturn valve (77), and the predetermined fuel oil pressure required for opening the nonreturn valve (77) is determined by the spring force of the non-return valve spring (87b).

In a possible implementation form of the first aspect, the method further comprises:

(e) slowly increasing the pressure of the supply of fuel oil to the suction valve fuel inlet (72) until the non-return valve (77) opens.

In a possible implementation form of the first aspect, the non-return valve (77) opens when the pressure of the supplied fuel oil overcomes the spring force of the non-return valve spring (87b).

In a possible implementation form of the first aspect, the method further comprises:

(f) observing the pressure of supplied fuel oil when fuel oil droplets or a stream of fuel oil flow reach out from the nozzle valve opening (61 b) to thereby determine an opening pressure for the non-return valve (77).

In a possible implementation form of the first aspect, the method further comprises:

(g) release the pressure of the supply of fuel oil to a pressure well below the determined opening pressure of the non-return valve (77), such as at least 10-20 bar or at least 30 bar below the determined opening pressure of the non-return valve (77).

In a possible implementation form of the first aspect, the method further comprises: (h) increasing the pressure of the supply of fuel oil to the suction valve fuel inlet (72) until it reaches a pressure being in the range of 3-5 bar below the determined opening pressure of the non-return valve (77); and

(i) checking whether any of the supplied fuel oil reaches out from the nozzle valve opening (61 b).

If the non-return valve is tight, no oil should be observed reaching out from the nozzle valve opening 61 b.

In a possible implementation form of the first aspect, the fuel oil is supplied by a fuel oil pump (37) in fluid connection with the suction valve fuel inlet, and the fuel oil pressure is read from a fuel oil pressure gauge (36).

In a possible implementation form of the first aspect, the method further comprises:

(j) turn off the fuel oil pump (37) while and wait about 15 seconds for the fuel oil pressure gauge (36) to stabilize and observe the fuel oil pressure at the fuel oil pressure gauge (36);

(k) wait about 60 seconds and observe the fuel oil pressure at the fuel oil pressure gauge (36).

In a possible implementation form of the first aspect, the method further comprises: releasing the predetermined lifting pressure from the nozzle valve piston cut-off shaft tip (61c) to thereby close the nozzle valve (61a) with the spring force of the nozzle valve spring (96) forcing the nozzle valve piston cut-off shaft (62) against the nozzle valve connection seat (88); supplying fuel oil at a second predetermined test fuel oil pressure to the suction valve fuel inlet (72), via the suction one-way valve (70) and the piston fuel oil opening (57b) to the non-return valve supply channel (75), said second predetermined test fuel oil pressure being higher than a predetermined fuel oil pressure required for opening the nonreturn valve (77); and checking whether any of the supplied fuel oil reaches out from the nozzle valve opening (61 b). If the nozzle valve 61a is tight, no oil should be observed reaching out from the nozzle valve opening 61 b.

In a possible implementation form of the first aspect, the second predetermined test fuel oil pressure is about 5 bar higher than the predetermined fuel oil pressure required for opening the non-return valve (77).

According to a second aspect there is provided a method of testing an injector valve (44) for a combustion engine, which injector valve (44) comprises: a plunger piston sealing chamber (136) with a plunger piston (58) for forming a plunger compression chamber (74), said plunger piston (58) being provided with a plunger piston fuel oil opening (57b) at the bottom and said plunger piston (58) being controlled by supply of plunger oil at a plunger oil pressure via a cover plunger oil supply channel (63); a suction one-way valve (70) for fuel oil inlet via a suction valve fuel inlet (72), a plunger chamber supply channel (73) for supply of fuel oil from the suction one-way valve (70) to the plunger compression chamber (74) or to the plunger piston fuel oil opening (57b); a non-return valve (77) in fluid connection with the plunger compression chamber (74) or the plunger piston fuel oil opening (57b) via a non-return valve supply channel (75) for supply of fuel oil to the non-return valve (77); a nozzle valve (61a) with a nozzle valve chamber (81), a nozzle valve piston cutoff shaft (62), a nozzle valve spring (96), a nozzle valve connection seat (88), and a nozzle valve opening (61 b), said nozzle valve piston cut-off shaft (62) having a nozzle valve piston cut-off shaft tip (61c) protruding through the opening (61b) of the nozzle valve (61a); a number of nozzle valve chamber supply channels (78a, 78b, 79a, 79b, 80a, 80b) providing a fluid connection from the non-return valve (77) to the nozzle valve chamber (81) for supply of fuel oil from the plunger compression chamber (74) or from the plunger piston fuel oil opening (57b) via the non-return valve (77) to the nozzle valve chamber (81); said method comprising: supplying plunger oil to the plunger piston (58) via the cover plunger oil supply channel (63) at a test plunger oil pressure, said test plunger oil pressure being equal to or larger than a plunger oil pressure required for maintaining the plunger piston (58) at the bottom of the plunger piston sealing chamber (136) to thereby close the plunger compression chamber (74) while maintaining a fluid connection from the plunger chamber supply channel (73) via the plunger piston fuel oil opening (57b) to the non-return valve supply channel (75); supplying fuel oil at a second predetermined test fuel oil pressure to the suction valve fuel inlet (72), via the suction one-way valve (70) and the piston fuel oil opening (57b) to the non-return valve supply channel (75), said second predetermined test fuel oil pressure being higher than a predetermined fuel oil pressure required for opening the nonreturn valve (77); and checking whether any of the supplied fuel oil reaches out from the nozzle valve opening (61 b).

If the nozzle valve 61a is tight, no oil should be observed reaching out from the nozzle valve opening 61 b.

In a possible implementation form of the second aspect, the second predetermined test fuel oil pressure is about 5 bar higher than the predetermined fuel oil pressure required for opening the non-return valve (77).

In a possible implementation form of the second aspect, the test plunger oil pressure is in the range of 280-320 bar, such as about 300 bar.

According to a third aspect there is provided a method of testing an injector valve (44) for a combustion engine, which injector valve (44) comprises: a plunger piston sealing chamber (136) with a plunger piston (58) for forming a plunger compression chamber (74), said plunger piston (58) being controlled by supply of plunger oil at a plunger oil pressure via a cover plunger oil supply channel (63), and said plunger piston (58) holding first and second plunger leakage channels (89,90) providing a fluid connection from the bottom of the plunger piston (58) to an upper sidewall part of the plunger piston (58); a suction one-way valve (70) for fuel oil inlet via a suction valve fuel inlet (72), a plunger chamber supply channel (73) for supply of fuel oil from the suction one-way valve (70) to the plunger compression chamber (74); a non-return valve (77) in fluid connection with the plunger compression chamber (74) via a non-return valve supply channel (75) for supply of fuel oil from the plunger compression chamber (74) to the non-return valve (77); a nozzle valve (61a) with a nozzle valve chamber (81), a nozzle valve piston cutoff shaft (62), a nozzle valve spring (96), a nozzle valve connection seat (88), and a nozzle valve opening (61 b), said nozzle valve piston cut-off shaft (62) having a nozzle valve piston cut-off shaft tip (61c) protruding through the opening (61b) of the nozzle valve (61a); and a number of nozzle valve chamber supply channels (78a, 78b, 79a, 79b, 80a, 80b) providing a fluid connection from the non-return valve (77) to the nozzle valve chamber (81) for supply of fuel oil from the plunger compression chamber (74) or from the plunger piston fuel oil opening (57b) via the non-return valve (77) to the nozzle valve chamber (81); and a third plunger compression leakage channel (91) providing a fluid connection from the plunger piston sealing chamber (136) to a fuel oil leakage outlet (92) positioned at an outer surface of the valve, wherein the third plunger compression leakage channel (91) has an inlet opening facing the plunger piston sealing chamber (136) at a position being faced by an outlet opening of the second plunger compression leakage channel (90) when the plunger piston (58) is in its most upper position within the plunger piston sealing chamber (136); said method comprising: supplying fuel oil at a predetermined leakage test fuel oil pressure to the suction valve fuel inlet (72), via the suction one-way valve (70) and the piston fuel oil opening (57b) to the plunger compression chamber, said predetermined leakage test fuel oil pressure being lower than a predetermined fuel oil pressure required for opening the nonreturn valve (77) and higher than a fuel oil pressure required for lifting the plunger piston (58) to its most upper position when no plunger oil pressure is applied to the plunger piston (58); and checking whether any of the supplied fuel oil reaches out from the fuel oil leakage outlet (92).

Fuel oil should be observed reaching out from the oil leakage outlet 92.

In a possible implementation form of the third aspect, the predetermined leakage test fuel oil pressure of step is in the range of 20 to 40 bar, such as in the range of 25 to 35 bar, such as about 30 bar.

In a possible implementation form of the third aspect, there is no supply of plunger oil at a plunger oil pressure to the plunger piston (58). In a possible implementation form of the third aspect, the injector valve under test (44) further comprises a hydraulic piston chamber (155) holding a hydraulic piston (64) connected to the nozzle valve piston cut-off shaft (62), said hydraulic piston (64) being controlled by supply of control oil at a control oil pressure via control oil supply channels (141 , 142) for opening and closing the nozzle valve (61a).

In a possible implementation form of the third aspect, the injector valve under test (44) further comprises sealing oil channels (131 , 132, 133, 134) in fluid connection with the plunger piston sealing chamber (136) for sealing the plunger piston (58), and in fluid connection with the hydraulic piston chamber (155) for sealing the hydraulic piston (64); and the method before the supply of fuel oil comprises a sealing step by supplying sealing oil at a first sealing oil pressure to the plunger piston sealing chamber (136) and the hydraulic piston chamber (155) via the sealing oil channels (131 , 132, 133, 135), said first sealing oil pressure being higher than or equal to a predetermined sealing oil pressure required for sealing of the plunger piston (58) within the plunger piston sealing chamber (23) and for sealing of the hydraulic piston (64) within the hydraulic piston chamber (155).

In a possible implementation form of the third aspect, the predetermined sealing oil pressure is in the range of 60-100 bar, such as in the range of 70-90 bar, such as around 80 bar.

According to a fourth aspect there is provided a method of testing an injector valve (44) for a combustion engine, which injector valve (44) comprises: a plunger piston sealing chamber (136) with a plunger piston (58) for forming a plunger compression chamber (74), said plunger piston (58) being controlled by supply of plunger oil at a plunger oil pressure via a cover plunger oil supply channel (63); a suction one-way valve (70) for fuel oil inlet via a suction valve fuel inlet (72), a plunger chamber supply channel (73) for supply of fuel oil from the suction one-way valve (70) to the plunger compression chamber (74); a non-return valve (77) in fluid connection with the plunger compression chamber (74) via a non-return valve supply channel (75) for supply of fuel oil from the plunger compression chamber (74) to the non-return valve (77); a nozzle valve (61a) with a nozzle valve chamber (81), a nozzle valve piston cutoff shaft (62), a nozzle valve spring (96), a nozzle valve connection seat (88), and a nozzle valve opening (61 b), said nozzle valve piston cut-off shaft (62) having a nozzle valve piston cut-off shaft tip (61c) protruding through the opening (61b) of the nozzle valve (61a); and a number of nozzle valve chamber supply channels (78a, 78b, 79a, 79b, 80a, 80b) providing a fluid connection from the non-return valve (77) to the nozzle valve chamber (81) for supply of fuel oil from the plunger compression chamber (74) or from the plunger piston fuel oil opening (57b) via the non-return valve (77) to the nozzle valve chamber (81); said method comprising:

(aa) supplying fuel oil at a predetermined nozzle valve test fuel oil pressure to the suction valve fuel inlet (72), via the suction one-way valve (70) to the plunger compression chamber (74), said predetermined nozzle valve test fuel oil pressure being lower than a fuel oil pressure required for opening the non-return valve (77);

(bb) supplying plunger oil to the plunger piston (58) via the cover plunger oil supply channel (63) at a first nozzle valve test plunger oil pressure, said first nozzle valve test plunger oil pressure being larger than or equal to a non-return valve plunger oil pressure required for opening the non-return valve (77) and smaller than or equal to a nozzle valve plunger oil pressure required for opening the nozzle valve (61a) by overcoming the force of the nozzle valve spring (96); and

(cc) checking whether any of the supplied fuel oil reaches out from the nozzle valve opening (61 b).

The suction one-way valve 70 for fuel oil inlet is a one-way valve, whereby fuel oil being compressed can only escape via the non-return valve 77 into the nozzle valve chamber 81. Since the nozzle valve 61a should not be open, no fuel oil should reach out from the nozzle valve opening 61 b.

In a possible implementation form of the fourth aspect, the predetermined nozzle valve test fuel oil pressure is equal to or larger than a predetermined fuel oil pressure required for lifting the plunger piston (58) to its most upper position when no plunger oil pressure is applied to the plunger piston (58). In a possible implementation form of the fourth aspect, the predetermined nozzle valve test fuel oil pressure of step (aa) is in the range of 20 to 40 bar, such as in the range of 25 to 35 bar, such as about 30 bar.

In a possible implementation form of the fourth aspect, the first nozzle valve test plunger oil pressure is in the range of 140-160 bar, such as about 150 bar.

In a possible implementation form of the fourth aspect, the injector valve under test (44) further comprises a hydraulic piston chamber (155) holding a hydraulic piston (64) connected to the nozzle valve piston cut-off shaft (62), said hydraulic piston (64) being controlled by supply of control oil at a control oil pressure via control oil supply channels (141 , 142) for opening and closing the nozzle valve (61a).

In a possible implementation form of the fourth aspect, the injector valve under test (44) further comprises sealing oil channels (131 , 132, 133, 134) in fluid connection with the plunger piston sealing chamber (136) for sealing the plunger piston (58), and in fluid connection with the hydraulic piston chamber (155) for sealing the hydraulic piston (64); and the method before the supply of plunger oil at step (bb) or before the supply of fuel oil at step (aa) comprises a sealing step by supplying sealing oil at a first sealing oil pressure to the plunger piston sealing chamber (136) and the hydraulic piston chamber (155) via the sealing oil channels (131 , 132, 133, 135), said first sealing oil pressure being higher than or equal to a predetermined sealing oil pressure required for sealing of the plunger piston (58) within the plunger piston sealing chamber (23) and for sealing of the hydraulic piston (64) within the hydraulic piston chamber (155).

In a possible implementation form of the fourth aspect, the predetermined sealing oil pressure is in the range of 60-100 bar, such as in the range of 70-90 bar, such as around 80 bar. In a possible implementation form of the fourth aspect, the non-return valve (77) comprises a non-return valve housing (87a), a non-return valve spindle (86), a non-return valve connection seat (76) and a non-return valve spring (87b) for forcing the non-return valve spindle (86) against the non-return valve connection seat (76) to thereby close the nonreturn valve (77), and the fuel oil pressure required for opening the non-return valve (77) is determined by the spring force of the non-return valve spring (87b).

In a possible implementation form of the fourth aspect, the method further comprises: (dd) increase the supply of plunger oil to the plunger piston (58) in steps from the first nozzle valve test plunger oil pressure to a final nozzle valve test plunger oil pressure, said final nozzle valve test plunger oil pressure being larger than the nozzle valve plunger oil pressure required for opening the nozzle valve (61a) by overcoming the force of the nozzle valve spring (96); and

(ee) after each step of increase in the supply of plunger oil then checking whether any of the supplied fuel oil reaches out from the nozzle valve opening (61 b).

In a possible implementation form of the fourth aspect, the final nozzle valve test plunger oil pressure is in the range of 175 to 200 bar, such as about 185 bar.

In a possible implementation form of the fourth aspect, the supply of plunger oil is increased in steps of 5 bar.

In a possible implementation form of the fourth aspect, the method further comprises: (ff) observing the pressure of supplied fuel oil when fuel oil droplets or a stream of fuel oil flow reach out from the nozzle valve opening (61 b) to thereby determine an opening pressure for the nozzle valve (61a).

In a possible implementation form of the fourth aspect, the method further comprises: (gg) changing the supply of plunger oil to the plunger piston (58) from the final nozzle valve test plunger oil pressure to a closed nozzle valve test plunger oil pressure, said closed nozzle valve test plunger oil pressure having a value in the range of 5 -10 bar below the determined opening pressure for the nozzle valve (61a); and

(hh) checking whether any of the supplied fuel oil reaches out from the nozzle valve opening (61 b). If the nozzle valve 61a is tight, no fuel oil should be observed.

The foregoing and other objects are achieved by the features of the independent claims. Further implementation forms are apparent from the dependent claims, the description and the figures. These and other aspects of the invention will be apparent from the embodiments described below.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following detailed portion of the present disclosure, the aspects, embodiments and implementations will be explained in more detail with reference to the example embodiments shown in the drawings, in which:

Fig. 1 is a diagram of a test system with lines for supply of control oil, sealing oil, constant oil, lifting oil, fuel oil and test gas for testing an injector valve being placed in a function test valve holder according to an example embodiment;

Fig. 2 is a perspective view of an assembled injector valve according to an example embodiment;

Fig. 3 is a longitudinal sectional view of the assembled injector valve of Fig. 2 according to an example embodiment;

Fig. 4 is a longitudinal sectional view of the assembled injector valve of Fig. 3 when turned a first angle according to an example embodiment;

Fig. 5 is a longitudinal sectional view of the assembled injector valve of Fig. 3 when turned a second angle according to an example embodiment;

Fig. 6 is an amplified longitudinal sectional view of the top cover of the assembled injector valve of Fig. 2 according to an example embodiment; Fig. 7 is a longitudinal sectional view of the assembled injector valve of Fig. 3 when turned a third angle according to an example embodiment;

Fig. 8 is an amplified view of the top cover with inlet ports of the assembled injector valve of Fig. 2 according to an example embodiment;

Fig. 9 is an amplified longitudinal sectional view of a part of the sectional view of Fig. 3, which part illustrates the arrangement of a suction one-way valve for fuel inlet, a plunger piston compression chamber for fuel compression, and a non-return valve for delivery of compressed fuel according to an example embodiment;

Fig. 10 is an amplified longitudinal sectional view of a part of the amplified sectional view of Fig. 9, which part shows the non-return valve of Fig. 9 at a first angle according to an example embodiment;

Fig. 11 is an amplified longitudinal sectional view showing the non-return valve of Fig. 9 at a second angle for illustrating the arrangement of supply channels for supply of compressed fuel to a nozzle valve according to an example embodiment;

Fig. 12 is an amplified longitudinal sectional view showing the arrangement of further supply channels for supply of compressed fuel to the nozzle valve according to an example embodiment;

Fig. 13 is an amplified longitudinal sectional view of a part of the sectional view of Fig. 5, which part illustrates the arrangement of control oil supply and drain channels for actuation of a hydraulic piston according to an example embodiment;

Fig. 14 is an amplified longitudinal sectional view of a part of the sectional view of Fig. 7, which part illustrates the arrangement of oil leakage channels for control and sealing oil leakage form the hydraulic piston according to an example embodiment;

Fig. 15 is an amplified longitudinal sectional view of a part of the assembled injector valve of Fig. 2, which part illustrates the arrangement of oil leakage channels for fuel oil leakage from the hydraulic piston according to an example embodiment; Fig. 16 is an amplified longitudinal sectional view of a part of the assembled injector valve of Fig. 2, which part illustrates the arrangement of oil leakage channels for collecting oil leakage from an intermediate valve part and from an atomizer part according to an example embodiment;

Fig. 17 is an amplified longitudinal sectional view of a part of the sectional view of Fig. 16, which part illustrates the arrangement of oil leakage chambers for collecting leakage oil at an upper and a lower surface of the intermediate valve part according to an example embodiment;

Fig. 18 is a cross-sectional view of an upper surface part of the intermediate valve part of Fig. 17, illustrating the arrangement of different oil channels with oil sealings according to an example embodiment;

Fig. 19 is a cross-sectional view of an upper surface part of a spindle guide housing facing a lower surface of the intermediate valve part of Fig. 17, illustrating the arrangement of different oil channels with oil sealings according to an example embodiment;

Fig. 20 is a perspective view of the injector valve of Fig. 2 with an atomizer unit nut and a corresponding atomizer being removed according to an example embodiment;

Fig. 21 illustrates the injector valve of Fig. 20 when placed in a function test valve holder with a spray chamber and a nozzle valve piston lifting unit according to an example embodiment;

Fig. 22 shows the function test valve holder of Fig. 21 from another angle illustrating the arrangement of a fuel oil inlet connection piece and a lifting oil connection piece according to an example embodiment;

Fig. 23 is an amplified longitudinal sectional view illustrating the arrangement of the injector valve of Fig. 20 relative to the nozzle valve piston lifting unit of the function test valve holder according to an example embodiment; Fig. 24 is an amplified longitudinal sectional view illustrating the arrangement of the injector valve of Fig. 20 relative to the fuel oil inlet connection piece of Fig. 22 according to an example embodiment;

Fig. 25 is an amplified longitudinal sectional view illustrating the arrangement of the injector valve of Fig. 20 relative to a fuel oil leakage outlet provided in a test sleeve of the function test valve holder of Fig. 21 according to an example embodiment;

Fig. 26 is a longitudinal sectional view illustrating the arrangement of the injector valve of Fig. 20 relative to the function test valve holder of Fig. 21 with a fuel oil drain sleeve for drain of oil from the fuel oil leakage outlet to the spray chamber according to an example embodiment;

Fig. 27 illustrates the assembled injector valve of Fig. 2 when placed in a detection test valve holder according to an example embodiment;

Fig. 28 is a longitudinal sectional view illustrating the arrangement of the injector valve of Fig. 2 relative to the detection test valve holder of Fig. 27, which detection test valve holder holds a test air inlet port and a number of test air outlet ports according to an example embodiment; and

Fig. 29 is a schematic diagram illustrating a test setup holding the detection test valve holder and injector valve of Fig. 28 with the test air outlet ports connection to a detection test liquid chamber according to an example embodiment.

LIST OF REFERENCE NUMBERS FOR THE DRAWINGS

Test system 1

Gas inlet 1a

Air inlet 1 b

Gas outlet 1c

Control oil outlet 1d

Sealing oil outlet 1e Fuel oil outlet 1f

Plunger oil outlet 1g

Lifting oil outlet 1 h

Constant oil outlet 1 i

Control/Sealing oil valve 2

Control oil directional valve 3

Control oil pressure relief valve 4

Hydraulic accumulator 5

Control/Sealing oil pressure gauge 6

Control/Sealing oil air driven pump 7

Control/Sealing oil pressure control valves 8 Control/sealing oil air pump safety valve 9 Plunger oil directional valve 10

Plunger oil pressure relief valve 11

Plunger oil pressure control valve 12

Plunger oil pressure gauge 13

Plunger oil pressure safety valve 14

Plunger oil air driven pump 15

Oil tank 16

Oil tank filler cap 17

Oil tank stop valve 18

Oil filter 19

Nitrogen booster 20

Booster oil pressure relief valve 21

Nitrogen inlet non-return valve 22

Nitrogen gas pressure control valve 23

Gas stop valve 24

Nitrogen gas pressure gauge 25

Constant oil valve 26

Lifting oil pressure relief valve 27

Lifting oil pressure control valves 28

Lifting oil air pump safety valve 29

Lifting oil pressure gauge 30 Lifting oil air driven pump 31

Fuel oil pressure relief valve 32

Fuel oil pressure control valves 33

Fuel oil air pump safety valve 34

Fuel oil pressure safety valve 35

Fuel oil pressure gauge 36

Fuel oil air driven pump 37

Fuel booster injector valve (FBIV) 44

Atomizer 43

Top cover 120

Plunger oil inlet port 49b

Control oil inlet port 130

Sealing oil inlet port 128

Constant oil inlet port 129

Barrel flange 121

Barrel body 122

Intermediate part 123

Spindle guide housing 124

Hydraulic piston bushing 125

Spindle guide union nut 127

Atomizer union nut 126

Spindle guide housing seal 201

Cover plunger oil channel 63

Cover fluid channels 56a, 56b, 56c

Air bleeding outlet 55

Plunger oil chamber 57a

Plunger piston 58

Plunger piston fuel oil opening 57b

Plunger piston head chamber 156

Plunger compression chamber 74

Plunger piston head seal 187

Plunger piston chamber seal 188 Plunger piston head chamber leakage channels 148, 149

Oil leakage outlets 157, 158

Plunger compression chamber leakage channels 89, 90, 91

Fuel oil leakage outlet 92

Plunger piston sealing bore 135

Plunger piston sealing chamber 136

Sealing oil channels 131 , 132, 133, 134

Suction one-way valve 70

Suction valve fuel inlet 72

Plunger chamber supply channel 73

Non-return valve 77

Non-return valve supply channel 75

Non-return valve connection seat 76

Non-return valve spindle 86

Non-return valve housing 87a

Non-return valve spring 87b

Non-return valve upper chamber 186

Non-return valve seal 185

Non-return valve leakage channels 144, 146

Non-return valve leakage chambers 145, 147

Nozzle valve chamber supply channels 78a, 78b, 79a, 79b, 80a, 80b

Control oil supply channels 140, 141

Control oil drain channels 142, 143a

(Drain channels 142 and 143a connect to constant oil port 129)

Control oil drain restriction 143b

Hydraulic piston 64

Hydraulic piston seal 189

Hydraulic piston actuation chamber 65

Hydraulic piston actuation chamber seal 184

Hydraulic piston chamber 155

Hydraulic piston bushing seals 190, 191 , 192, 193

Hydraulic piston sealing bore 137

Hydraulic piston sealing channel 138 Hydraulic piston sealing chamber 139

Hydraulic piston bushing leakage channel 154 Hydraulic piston bushing leakage chamber 153 Control and sealing oil leakage channels 150, 151 , 152

Nozzle valve 61a

Nozzle valve opening 61b

Nozzle valve piston cut-off shaft 62

Nozzle valve piston cut-off shaft tip 61c

Nozzle valve piston guide 95

Nozzle valve connection seat 88

Nozzle valve chamber 81

Nozzle valve spring 96

Nozzle valve lower chamber 82

Nozzle valve piston leakage chamber 159 Nozzle valve bushing leakage chamber 161 Fuel oil leakage channels 160, 162, 163, 164

Atomizer fuel oil leakage chamber 194 Atomizer fuel oil leakage channel 168 Intermediate leakage oil collecting channel 169 Intermediate leakage oil outlet channel 197 Intermediate outer leakage oil chamber 198 Upper oil leakage channel 167

Upper oil leakage outlets 165, 166

Intermediate upper leakage oil chamber 170 Spindle guide upper leakage oil chamber 171 Intermediate upper sealing rings 172, 173,174, 175, 176, 177, 178 Spindle guide upper sealing rings 179, 180, 181 , 182, 183

Spindle guide union nut inner sealing ring 199 Spindle guide union nut outer sealing ring 200 Barrel body outer sealing rings 205, 206, 207, 208, 209

Plunger oil connecting piece 49a

Control oil connecting piece 50

Sealing oil connecting piece Constant oil connecting piece 52

Air bleed stop valve 53

Air bleed drain hose 54

Function test valve holder 45

Function test top plate 46a

Nozzle valve piston lifting unit 46b

Valve holder nuts 46c

Function test valve connecting nuts 46d

Function test sleeve 46e

Oil injection chamber 59

Drain hose hole 60

Fuel oil inlet connecting piece 47

Lifting oil connecting piece 48b

Lifting oil channels 66

Lifting piston 67

Piston push up distance 68

Lifting unit fuel oil leakage channels 83, 84

Lifting unit fuel oil outlet 85

Fuel inlet channel 71

Function test sleeve fuel oil leakage outlet 93

Fuel oil drain sleeve 94

Detection test valve holder 97a

Detection test sleeve 97b

Detection test top plate 97c

Detection test bottom plate 97d

Plunge oil plug 115

DTS air inlet port 107

DTS air inlet channel 195

DTS air inlet chamber 196

DTS lower air outlet chamber 203

DTS lower air outlet port 110 DTS bottom air outlet chamber 204

DTS bottom air outlet port 114

DTS barrel body air outlet chamber I 210

DTS barrel body air outlet port I 111

DTS barrel body air outlet chamber II 211

DTS barrel body air outlet port II 113

DTS barrel body air outlet chamber III 212

DTS barrel body air outlet port III 112

Detection test liquid drain valve 108

Detection test hoses 98, 99, 100, 101 , 102, 103, 104, 105

Non-return valves 109a, 109b, 109c, 109d, 109e, 109f , 109g, 109h

Detection test liquid chamber 106

DETAILED DESCRIPTION

An injector valve according to a preferred embodiment is designed by MAN Energy Solutions for a two-stroke combustion engine. The engine is a duel fuel engine, which can run on standard heavy fuel oil or on a liquefied petroleum gas, LGP, such as a mixture of propane and butane.

The injector valve may be used as a fuel booster injection valve for the liquefied petroleum gas, LGP, and may be designed for performing two functions: to pressurize or boost the LPG to the desired injection pressure, and to ensure the correct timing and duration of the LPG injection.

During normal operation, the injector valve is supplied with sealing oil, plunge oil, control oil, constant oil, and liquid petroleum gas, LPG, as fuel. Sealing oil is to prevent internal leak of liquid gas from entering unintended areas of the injector valve. Plunge oil is to pressurize the fuel, LPG. Control oil is to control the timing of opening the injector valve for delivering compressed fuel gas to the combustion chamber. Liquid fuel is supplied to the injector valve constantly. As long as the control oil is supplied, the injector valve will be closed, and when the supply of control oil is stopped, the valve will open when the pressure provided by the plunge oil to the fuel overcomes the opening pressure of the valve. The supplied constant oil runs opposite to the direction of supplied control oil, and when control oil is supplied, a pressure is built up in the valve for closing the valve, and when the supply of control oil stops, there is no counter pressure to the supplied constant oil and the valve opens.

An embodiment of the fully assembled injector valve 44 is described in the following with reference to Figs. 2 to 19.

The injector valve holds a top cover 120, a barrel body 122 with a barrel flange 121 , a spindle guide housing 124, an intermediate part 123 between the barrel body 122 and the spindle guide housing 124, a spindle guide union nut 127 for connecting the barrel body 122 with the intermediate part 123 and the spindle guide housing 124, and atomizer union nut 126 holding an atomizer 43 for output of the compressed fuel gas. See Figs. 2 and 3.

The top cover 120 holds a plunger oil inlet port 49b, a control oil inlet port 130, a sealing oil inlet port 128, a constant oil inlet port 129, which during normal operation functions as a control oil drainage port, but which during test can be used for supply of oil at a constant pressure, and an air bleeding outlet 55. The top cover 120 further holds cover plunger oil channel 63 in direct fluid connection with the plunger oil inlet port 49b, and cover fluid channels 56a, 56b, 56c, in fluid connection with the air bleeding outlet 55. See Figs. 3, 4, 5, 6 and 8.

The barrel body 122 holds a plunger piston 58, see Figs. 3 and 4, inserted into a plunger piston sealing chamber 136 and a plunger piston head chamber 156. The plunger piston 58 has an upper piston head moving within the plunger piston head chamber 156, while the bottom of plunger piston 58 faces a plunger compression chamber 74. In the bottom of plunger piston 58 there is provided a plunger piston fuel oil opening 57b. The length of the plunger piston head chamber 156 determines the maximum movement of the plunger piston 58 and thereby the minimum size of the compression chamber 74. The pressure of any fuel within the compression chamber 74 will be determined by the pressure provided to the top of the plunger piston 58. A plunger head seal 187 is provided in the head of the plunger piston 58 for sealing the connection between the head of the plunger piston 58 and the plunger head chamber 156, and a piston chamber seal 188 is provided in the barrel body 122 for sealing the connection between plunger piston 58 and the compression chamber 74. A bottom part of the plunger piston 58 holds two plunger compression chamber leakage channels 89 and 90, which can be in fluid connection with a third plunger compression chamber leakage channels 91 and a fuel oil leakage outlet 92, both arranged in the barrel body 122. When the plunger piston 58 is in the upper position, leakage channels 89 and 90 are in fluid connection with leakage channel 91 and thereby the fuel oil leakage outlet 92. When plunger oil is supplied to the plunger oil channel 63 via the plunger oil inlet port 49b, the plunger piston 58 is pressed downwards and a plunger oil chamber 57a is formed between the head of the plunger piston 58 and the bottom of the top cover 120, see Fig. 6.

The barrel body 122 also holds plunger piston head chamber leakage channels 148, 149 for drainage of leaked plunger oil from the plunger piston head chamber 156 into corresponding oil leakage outlets 158, 158, see Fig. 7. The sealing oil inlet port 128 is in fluid connection with sealing oil channels 131 , 132, 133 and 134, which are provided in the barrel body 122, the intermediate part 123, and the spindle guide housing 124. The sealing oil channels are fluidly connected to a plunger piston sealing bore 135 for supply of sealing oil to the plunger piston sealing chamber 136.

A suction one-way valve 70 with a suction valve inlet port 72, see Figs. 4 and 9, is provided in the barrel body 122 for supply of fuel to the plunger compression chamber 74 via a plunger chamber supply channel 73. Compressed fuel is led from the plunger piston compression chamber 74 into a non-return valve 77 via a non-return valve supply channel 75. When the plunger piston 58 is at the bottom of the plunger piston compression chamber 74, the fuel is supplied from the plunger chamber supply channel 73 via the plunger piston fuel oil opening 57b into the non-return valve supply channel 75.

The non-return valve 77, see Figs. 10 and 11 , is formed by a non-return valve housing 87a holding a non-return valve spindle 86, which is pressed through a non-return valve connection seat 76 by a non-return valve spring 87b. When the pressure from supplied fuel is larger than the pressure from the spring 87b, the non-return valve 77 opens and fuel is supplied from nozzle-valve chamber supply channels 78a, 78b in the barrel body 122, via nozzle-valve chamber supply channels 79a, 79b in the intermediate part 123, through nozzle-valve chamber supply channels 80a, 80b in the spindle guide housing 124 into a nozzle valve chamber 81 formed in the spindle guide housing, see Figs. 11 and 15. A non-return valve upper chamber 186 is formed around the upper part of the non-return valve housing 87a and a non-return valve seal 185 is provided as a seal between the nonreturn valve housing 87a and the barrel body 122. A first non-return valve leakage chamber 145 is provided for collection of fuel leaking through the seal 185, which first leakage chamber 145 is in fluid connection with a first non-return valve leakage channel 144, which ends in the fuel oil leakage outlet 92. A second non-return valve leakage chamber 147 inside the non-return valve housing 87a is via a second non-return valve leakage channel in fluid connection with the first non-return valve leakage chamber 145, see Fig. 3 and 10.

The spindle guide housing 124 holds a hydraulic piston 64 within a hydraulic piston bushing 125, see Fig. 15. The hydraulic piston 64 connects to a nozzle valve piston guide 95 further connected to a nozzle valve piston cut-off shaft 62 forming part of a nozzle valve 61a. The nozzle valve 61a holds a nozzle valve spring 96 within the nozzle valve chamber 81 for pressing the nozzle valve piston cut-off shaft 62 against a nozzle valve connection seat 88, with a nozzle valve lower chamber 82 being formed above the connection seat 88. The nozzle valve piston cut-off shaft 62 holds a nozzle valve piston cut-off shaft tip 61c protruding through a nozzle valve opening 61b. When there is no pressure on the hydraulic piston 64, and when the pressure from fuel supplied via channels 80a and 80b is larger than the pressure from the spring 96, the nozzle valve 61a opens and fuel flows is sprayed out via the nozzle valve opening 61 b and the atomizer 43.

The pressure on the hydraulic piston 64 is determined by the pressure of supplied control oil. The control oil is supplied from the control oil inlet port 130 via a first control oil supply channel 140 in the barrel body and a second control oil supply channel 141 in the intermediate part 123 to a hydraulic piston actuation chamber 65 formed on top of the hydraulic piston 64. When the supply of control oil is stopped, the control oil is drained from the piston actuation chamber 65 to the constant oil inlet port 129 via a control oil drain restriction 143b and a first control oil drain channel 143a in the intermediate part 123, and further via a second control oil drain channel in the barrel body 122, see Figs. 5 and 15.

Sealing oil is supplied to the hydraulic piston bushing 125 from the sealing oil inlet port 128 via the sealing oil channel 134 into a hydraulic piston sealing bore 137, which is fluidly connected to a hydraulic piston sealing channel 138 and a hydraulic piston sealing chamber 139 facing the hydraulic piston 64 for sealing the piston 64 within the bushing 125, see Figs. 4 and 14. The upper part of the hydraulic piston 64 holds a hydraulic piston head moving within a hydraulic piston chamber 155, and the hydraulic piston head holds a hydraulic piston seal 189 for sealing the hydraulic piston head within the hydraulic piston chamber 155. The lower surface part of the intermediate part 123 holds a hydraulic piston actuation chamber seal 184 for sealing the hydraulic piston actuation chamber 65, see Fig. 14.

A number of seals, sealing chambers and sealing channels are provided in connection with the hydraulic piston bushing 125 as illustrated in Figs. 14 and 15 and discussed in the following. Control oil may leak through the hydraulic piston seal 189 into the hydraulic piston chamber 155 from where it may flow to a hydraulic piston bushing leakage chamber 153 via a hydraulic piston bushing leakage channel 154. From the leakage chamber 153 the leaked control oil may flow to the oil leakage outlet 158 via first, second and third control and sealing oil leakage channels 152, 151 and 150. The hydraulic piston bushing 125 holds a first upper hydraulic piston bushing seal 190 for sealing of control oil, which may flow from the actuation chamber 65 via the seal 189 and into the hydraulic piston bushing leakage chamber 153. The hydraulic piston bushing 125 also holds a second hydraulic piston bushing seal 191 for sealing of sealing oil, which may flow from the sealing bore 137 to the leakage chamber 153, and a third hydraulic piston bushing seal 192 for sealing of sealing oil, which may flow from the sealing bore 137 into a nozzle valve bushing leakage chamber 161 , which is fluidly connected to a first fuel oil leakage channel 162 in the spindle guide housing 124, a second fuel oil leakage channel 163 in the intermediate part 123, and a third fuel oil leakage channel 164 in the barrel body 122. Around the connection between the hydraulic piston 64 and the nozzle valve piston guide 95, a nozzle valve leakage chamber 159 is provided, which is connected to the leakage chamber 161 via a fourth fuel oil leakage channel 160, whereby supplied fuel leaking from the nozzle valve chamber 81 along the nozzle valve piston guide 95 can flow from the leakage chamber 161 to the first fuel oil leakage channel 164.

Figs. 16 and 17 show the arrangement of further leakage chambers and channels. Fuel oil supplied from the nozzle valve chamber 81 , via the nozzle valve lower chamber 88 and passing the nozzle valve piston cut-off shaft 62 may leak into an atomizer fuel oil leakage chamber 194 between the atomizer 43 and atomizer union nut 126. From leakage chamber 194 the leaked fuel oil may pass an atomizer fuel oil leakage channel 168 and a spindle guide upper leakage oil chamber 171 in the spindle guide housing 124, an intermediate upper leakage oil chamber 170 and an intermediate leakage oil collecting channel 169 in the intermediate part 123, an into an upper oil leakage channel 167 in the barrel body 122, and out via a upper oil leakage outlets 165 and 166, which are fluidly connected to the upper oil leakage channel 167. An intermediate outer leakage chamber 198 is provided between the intermediate part 123 and the spindle guide union nut 127, and an intermediate leakage oil outlet channel 197 connects the channel 169 to the leakage chamber 198.

The intermediate part 123 has a number of supply and leakage channels passing through between the barrel body 122 and the spindle guide housing 124, which demands a corresponding number of seals. This is illustrated in Figs. 18 and 19, where Fig. 18 is a cross-sectional view of an upper surface part of the intermediate valve part 123, and Fig. 19 is a cross-sectional view of an upper surface part of the spindle guide housing 124 facing a lower surface of the intermediate valve part 123.

In Fig. 18, a first intermediate upper sealing ring 172 seals the second control oil supply channel 141 , a second intermediate upper sealing ring 173 seals the first control oil drain channel 143a, a third intermediate upper sealing ring 174 seals the sealing oil channel 133, a fourth intermediate upper sealing ring 175 seals the second control and sealing oil leakage channel 151 , a fifth intermediate upper sealing ring 176 seals the second fuel oil leakage channel 163, a sixth intermediate upper sealing ring 177 seals the nozzle valve supply channel 79a, and a seventh intermediate upper sealing ring 178 seals the nozzle valve supply channel 79b. The intermediate upper leakage oil chamber 170 is provided between the sealing rings 172, 173, 174, 175, 176, 177 and 178 for collection of leaked oil and, with the leakage oil chamber 170 being connected to the intermediate leakage oil collecting channel 169.

In Fig. 19 a first spindle guide upper sealing ring 179 seals the nozzle valve supply channel 79b, a second spindle guide upper sealing ring 180 seals the nozzle valve supply channel 79a, a third spindle guide upper sealing ring 181 seals the second fuel oil leakage channel 163, a fourth spindle guide upper sealing ring 182 seals the second control and sealing oil leakage channel 151 , and a fifth spindle guide upper sealing ring 183 seals the sealing oil channel 133. The spindle guide upper leakage oil chamber 171 is provided between the sealing rings 179, 180, 181 , 182 and 183 for collection of leaked oil and, with the leakage oil chamber 171 being connected to the intermediate leakage oil collecting channel 168. The upper surface part of the spindle guide housing 124 also has a centre opening for connection to the hydraulic piston bushing 125 holding the hydraulic piston 64.

A spindle guide union nut inner sealing ring 199 is provided as a seal between the spindle guide union nut 127 and the spindle guide housing 124, and a spindle guide housing seal 201 is provided as a seal between the atomizer union nut 126 and the spindle guide housing 124, see Fig. 16. Furthermore, a spindle guide union nut outer sealing ring 200 is provided at the outside of the spindle guide union nut 127, which is also illustrated in Fig. 16.

In order to perform a function test of the injection valve 44 of Fig. 2, the atomizer union nut 126 and the atomizer 43 are removed from the injection valve as illustrated in Fig. 20. This leaves the spindle guide housing 124 uncovered with the tip of the nozzle valve piston cutoff shaft 62 protruding at the end of the spindle guide housing 124. The spindle guide union nut 127 is maintained. The function test includes a test of the non-return valve 77, which requires that the nozzle valve piston cut-off shaft 62 is lifted from the nozzle valve connection seat 88 to keep the nozzle valve open.

When performing the function test, the injection valve 44 of Fig. 20 is installed in a function test valve holder 45, see Figs. 21 to 26, and supplied with oil and gas for testing delivered by the test system 1 of Fig. 1.

The function test valve holder 45 holds a function test top plate 46a, a nozzle valve piston lifting unit 46b, valve holder nuts 46c for connecting the function test top plate 46a with the lifting unit 46b, a function test sleeve 46e, and an oil injection chamber 59 beneath the lifting unit 46b. A drain hose hole 60 goes through the lifting unit 46b into the drain hose chamber 59. Function test valve connecting nuts 46d holds the injection valve 44 of Fig. 20 in position during the function test. The function test sleeve 46e is dimensioned to fit to the barrel body 122 of the injector valve 44 and holds a fuel inlet channel 71 facing the suction valve inlet port 72 of the barrel body 122, and a fuel oil connecting piece 47 is connected to the fuel inlet channel 71 for inlet of fuel oil. A function test sleeve fuel oil leakage outlet 93 is provided in the function test sleeve 46a and faces the fuel oil leakage outlet 92 of the barrel body 122. A fuel oil drain sleeve 94 can be connected to the fuel oil leakage outlet 93 and passed through the drain hose hole 60 into the drain hose chamber 59.

In orderto connect to the supply lines of the test system 1 of Fig. 1 , a plunger oil connecting piece 49a is connected to the plunger oil inlet port 49b, a control oil connecting piece 50 is connected to the control oil inlet port 130, a sealing oil connecting piece 51 is connected to the sealing oil inlet port 128, and a constant oil connecting piece 52 is connected to the constant oil inlet port 129. The air bleeding outlet 55 is provided with an air bleed stop valve 53, which connects to an air bleed drain hose 54. During a preliminary deaeration process, the air bleed stop valve 53 is open and the air bleed drain hose 54 is led through the drain hose hole 60 into the oil injector chamber 59.

The nozzle valve piston lifting unit 46b holds has a lifting oil channel 66 connected to a lifting oil connecting piece 48 for input of lifting oil from the test system 1 . A centre part of the lifting unit 46b is dimensioned to fit closely to the protruding tip of the nozzle valve piston cut-off shaft 62 when inserted into the function test valve holder 45, and a lifting piston 67 is arranged in the lifting unit 46b for lifting the the nozzle valve piston cut-off shaft 62 when lifting oil is supplied to the lifting oil channel 66. The length of the lifting of the nozzle valve piston cut-off shaft 62 is here denoted piston push up distance 68. Fuel oil may leak along the lifted nozzle valve piston cut-off shaft 62 into lifting unit fuel oil leakage channels 83, 84 and out into the oil injection chamber 59 via a lifting unit fuel oil outlet 85.

The fully assembled injection valve 44 of Fig. 2 is exposed to a leakage detection test and placed in a detection valve holder 97a when performing the leakage detection test and supplied with air at 7 bar for detection of any leakages. In orderto fluidly separate different outer parts of the valve 44 during the leakage detection test, first, second, third, fourth and fifth barrel body outer sealing rings 205, 206, 207, 208 and 209 are provided at the outer part of the barrel body 122 as illustrated in fig. 28.

The detection valve holder 97a, see Figs. 27, 28 and 29, holds a detection test sleeve 97b, a detection test top plate 97c, and a detection test bottom plate 97d. The detection test bottom plate 97d has a center opening dimensioned to fit the atomizer 43 of the assembled injector valve 44, whereby the atomizer protrudes the bottom plate 97d into a detection test sleeve, DTS, bottom air outlet chamber 204, having a detection test sleeve, DTS, bottom air outlet port 114 and a detection test liquid drain valve 108.

When fully assembled injector valve 44 is positioned in the detection valve holder 97a, with the injector valve 44 holding the plunger oil connecting piece 49a, the control oil connecting piece 50, the sealing oil connecting piece 51 , and the constant oil connecting piece 52. The air bleeding outlet 55 is provided with the air bleed stop valve 53, which is closed during the leakage detection test and a plunge oil plug 115 is inserted into the plunger oil connecting piece 49a.

The detection test sleeve 97b is dimensioned to fit to the barrel body outer sealing rings 205, 206, 207, 208, 209 thereby forming a number of air inlet and outlet chambers. The detection test sleeve 97b further holds a number of corresponding air inlet and outlet ports, which is illustrated in Fig. 28. The detection test sleeve 97b hence holds a detection test sleeve, DTS, air inlet port 107 and a detection test sleeve, DTS, air inlet channel 195 leading into a detection test sleeve, DTS, air inlet chamber 196 being sealed by sealing rings 200 and 209; a detection test sleeve, DTS, lower air outlet port 110 facing a detection test sleeve, DTS, lower air outlet chamber 203 being sealed by sealing ring 200; a detection test sleeve, DTS, barrel body air outlet port 1 111 facing a detection test sleeve, DTS, barrel body outlet chamber I 210 being sealed by sealing rings 209 and 208; a detection test sleeve, DTS, barrel body air outlet port II 113 facing a detection test sleeve, DTS, barrel body outlet chamber II 211 being sealed by sealing rings 206 and 205; a detection test sleeve, DTS, barrel body air outlet port III 112 facing the fuel oil leakage outlet 92 of the barrel body 122 being sealed by sealing rings 208 and 207; and a detection test sleeve, DTS, barrel body outlet chamber III 212 being sealed by sealing rings 207 and 206.

A detection test liquid chamber 106 is provided holding a liquid and detection test hoses, which are connected to the air outlet ports and connecting pieces, are ending in the liquid chamber 106 to thereby detect any air leakage by bubbles in the liquid chamber 106. The detection test hoses are connected as follows: detection test hose 98 is connected to the control oil connecting piece 50, detection test hose 99 is connected to the sealing oil connecting piece 51 , detection test hose 100 is connected to the constant oil connecting piece 52, detection test hose 101 is connected to DTS barrel body air outlet port II 113, detection test hose 102 is connected to DTS barrel body air outlet port III 112, detection test hose 103 is connected to DTS barrel body air outlet port 1 111 , detection test hose 104 is connected to DTS lower air outlet port 110, and detection test hose 105 is connected to DTS bottom air outlet port 114. Each of the detection test hoses holds a nonreturn valve 109.

Fig. 1 is a diagram of showing the test system 1 used for performing the function test of the injection valve 44 of Fig. 20.

The test system 1 comprises a gas inlet 1a, an air inlet 1b, a gas outlet 1c, a control oil outlet 1 d, a sealing oil outlet 1e, a fuel oil outlet 1 f, a plunger oil outlet 1g, a lifting oil outlet 1 h and a constant oil outlet 1 i. Air is provided via the air inlet 1 b at a pressure in the range of 7 - 10 bar in , which pressurized air is used as input to pressure control valves, a plunger oil pressure control valve 12, lifting oil pressure control valve 28, control/sealing oil pressure control valve 8, and fuel oil pressure control valve 33. A gas inlet 1a is provided for inlet of a test gas in the form of Nitrogen at a pressure in the range of 80-300 bar. The pressurized Nitrogen is supplied to a Nitrogen booster 20 via a Nitrogen inlet non-return valve 22, and from the Nitrogen booster 20 the Nitrogen is supplied to a gas stop valve 24, with a Nitrogen gas pressure control valve 23 provided for controlling the pressure of the gas being output from the gas stop valve 24 to gas outlet 1c.

In order to deliver a test fluid in the form of a hydraulic oil, which may be a mineral hydraulic oil with a viscosity of 10 centistokes (cSt), an oil tank 16 is provided for holding the hydraulic oil. The oil tank 16 is provided with an oil tank filler cap 17, an oil tank stop valve 18, and an oil filter 19. An outlet of the oil tank 16 is via the stop valve 18 and oil filter 19 connected to four air driven pumps, a plunger oil air driven pump 15 being controlled by the plunger oil pressure control valve 12, a control/sealing oil air driven pump 7 being controlled by the control/sealing oil pressure control valve 8 and the control/sealing oil air pump safety valve 9, a lifting oil air driven pump 31 being controlled by the lifting oil pressure control valve 28 and the lifting oil air pump safety valve 29, and a fuel oil air driven pump 37 being controlled by the fuel oil pressure control valve 33 and the fuel oil air pump safety valve 34. The oil pressure from the plunger oil air drive pump 15 can be read from plunger oil pressure gauge 13, the oil pressure from the control/sealing oil air driven pump 7 can be read from a control/sealing oil pressure gauge 6, and the oil pressure from the fuel oil air driven pump 37 can be read from a fuel oil pressure gauge 36.

A hydraulic accumulator 5 is provided, which accumulator 5 may be charged by fuel oil up to a pressure of 250 bar. However, in the present test system 1 the maximum fuel oil pressure is 50 bar. The hydraulic accumulator 5 is a membrane type of accumulator. It has a chamber which is divided by a rubber membrane. On one side of the membrane is Nitrogen at a pressure of 20-25 bar, on the other side of the membrane is hydraulic oil supplied from the fuel oil air driven pump 37. While the pressure of hydraulic oil is 0 bar, then the whole volume of accumulator is filled with Nitrogen. While applying hydraulic oil at a pressure above 2-25 bar, then the Nitrogen will start compress, as the hydraulic oil will start filling the volume of hydraulic accumulator. The purpose of the accumulator 5 in the test system 1 is to accumulate hydraulic oil inside with a pressure of 20-25 bar and to reduce oil pressure fluctuation coming from the fuel oil air driven pump 37.

A plunger oil directional valve 10 is provided for opening and closing of plunger oil supply, which can be supplied from the plunger oil air driven pump 15 or from the Nitrogen booster 20 to the plunger oil outlet 1 g. The oil pressure from the plunger oil air driven pump 15 can be read from a plunger oil pressure gauge 13, while the oil pressure from the plunger oil air driven pump 15 can be released by a plunger oil pressure relief valve 11 , in which case released hydraulic oil will flow back to the oil tank 16. A plunger oil pressure safety valve 14 is provided. The plunger oil pressure safety valve 14 is adjusted to a maximum working pressure of 320 bar at the output side of the plunger oil air driven pump 15. If the plunger oil pressure exceeds the 320 bar, the plunger oil safety valve 14 will open and hydraulic oil will flow back to the oil tank 16.

The plunger oil directional valve 10 is also connected to the Nitrogen booster 20 via a booster oil pressure relief valve 21. The Nitrogen booster 20 holds an inlet chamber with Nitrogen and an outlet chamber with hydraulic oil, which may be boosted in pressure by increasing the pressure of Nitrogen in the inlet chamber. When both the plunger oil pressure relief valve 11 and the plunger oil directional valve 10 are closed, the oil pressure of the outlet chamber in Nitrogen booster 20 can determined by the pressure of supplied Nitrogen and by the oil pressure produced the plunger oil air driven pump 15, and when opening the plunger oil directional valve 10, the oil pressure is supplied to the plunger oil outlet 1g.

Fuel oil is provided from the fuel oil air driven pump 37 to the fuel oil outlet 1f, and the oil pressure from the fuel oil air driven pump 37 can be read from the fuel oil pressure gauge 36, while the oil pressure from the fuel oil air driven pump 37 can be released by a fuel oil pressure relief valve 32, in which case released hydraulic oil will flow back to the oil tank 16. A fuel oil pressure safety valve 35 is provided for protection of the fuel oil pressure gauge 36. The fuel oil pressure safety valve 35 is adjusted to a maximum working pressure of 60 bar at the output side of the fuel oil air driven pump 37. If the fuel oil pressure exceeds the 60 bar, the fuel oil safety valve 35 will open and hydraulic oil will flow back to the oil tank 16.

A control/sealing oil directional valve 2 is provided for opening and closing of oil supply from the control/sealing oil air driven pump 7 to the sealing oil outlet 1e or to a control oil directional valve 3, which controls opening an closing of oil supply to the control oil outlet 1d. The oil pressure from the control/sealing oil air driven pump 7 can be read from the control/sealing oil pressure gauge 6, while the oil pressure from the control/sealing oil air driven pump 7 can be released by a control oil pressure relief valve 4, in which case released hydraulic oil will flow back to the oil tank 16.

Lifting oil is provided from the lifting oil air driven pump 31 to the lifting oil outlet 1 h, and the oil pressure from the lifting oil air driven pump 31 can be read from the lifting oil pressure gauge 30, while the oil pressure from the lifting oil air driven pump 30 can be released by a lifting oil pressure relief valve 27, in which case released hydraulic oil will flow back to the oil tank 16.

A constant oil valve 26 is provided for opening and closing of oil supply to the constant oil outlet 1 i, which is supplied with oil directly from the oil tank 16 via the oil tank stop valve 18 and oil filter 19. There is no air driven pump for generating an oil pressure in the oil supply line between the oil thank 16 and the constant oil outlet 1 i.

Function test of injector valve The function test includes a test of the non-return valve 77, which requires that the nozzle valve piston cut-off shaft 62 is constantly held in a lifted position from the nozzle valve connection seat 88 to keep the nozzle valve open. The test of the non-return valve 77 is followed by several tests, for which the nozzle valve piston cut-off shaft 62 is in the normal operating mode. These tests include a test of the tightness of the nozzle valve piston cutoff shaft 62 against the nozzle valve connection seat 88, a test of a fuel injection sequence, and an indirectly test of the suction one-way valve 70.

In order to perform a function test of the injection valve 44 of Fig. 2, the atomizer union nut 126 and the atomizer 43 are removed from the injection valve as illustrated in Fig. 20. This leaves the spindle guide housing 124 uncovered with the tip of the nozzle valve piston cutoff shaft 62 protruding at the end of the spindle guide housing 124. The spindle guide union nut 127 is maintained. When performing the function test, the injection valve 44 of Fig. 20 is installed in the function test valve holder 45, see Fig. 21.

The plunger oil connecting piece 49a is connected to the plunger oil inlet port 49b, the control oil connecting piece 50 is connected to the control oil inlet port 130, the sealing oil connecting piece 51 is connected to the sealing oil inlet port 128, the constant oil connecting piece 52 is connected to the constant oil inlet port 129, and the air bleed stop valve 53 is connected to the air bleeding outlet 55. The top cover 120 of the valve 44 is secured to the function test valve holder 45 by two function test valve connecting nuts 46d.

Before start of the test procedures, the test system 1 need to be configured to the initial settings as follows:

Air inlet 1b is connected to an external source of compressed air min 7 bar max 10bar, and gas inlet 1a is connected to an external source of nitrogen min 80bar.

The hydraulic accumulator 5 is filled with nitrogen up to 20-25 bar.

The fuel oil pressure safety valve 35 is adjusted to pressure 60bar (the purpose of safety valve 35 is to protect fuel oil pressure gauge 36 with range 0-60bar). Safety valve 14 is adjusted to 320bar. All pressure relief valves 4, 11 , 27, 32 are set open.

The pressure control valves 33, 8, 28 and 12 are set in closed position to obtain an outlet pressure of the valves of 0 bar.

The air pump safety valves are adjusted to max pressure: Fuel oil air pump safety valve 34 is adjusted to a pressure allowing the fuel oil air driven pump 37 to deliver an oil pressure of max 50 bar.

Control/sealing oil air pump safety valve 9 is adjusted to a pressure allowing the control/sealing oil air driven pump 7 to deliver an oil pressure of max 300 bar. Lifting oil air pump safety valve 29 is adjusted to a pressure allowing the lifting oil air driven pump 31 to deliver an oil pressure of max 300 bar.

The oil tank stop valve 18 is set open.

The gas stop valve 24 is set closed

The oil tank 16 is filled with clean hydraulic oil with 7-10 cSt viscosity.

Flexible hoses are connected to the oil outlets 1 f, 1 d, 1 e,1 i, 1 h, 1 g., with the other ends of hoses being provided with quick couplings which are normally closed. When the quick couplings are connected to corresponding connecting pieces on the injector valve and the test valve holder, the quick couplings opens. The gas outlet port 1 c is equipped with a quick coupling which is normally closed

The oil outlets of the test system 1 are fluidly connected via the hoses and quick couplings to the oil connecting pieces by connecting the control oil outlet 1d to the control oil connecting piece 50, connecting the sealing oil outlet 1 e to the sealing oil connecting piece 51 , connecting the plunger oil outlet 1 g to the plunger oil connecting piece 49a, connecting the constant oil outlet 1 i to the constant oil connecting piece 52, connecting the fuel oil outlet 1f to the fuel oil inlet connecting piece 47, which is connected to the function test sleeve 46e, and connecting the lifting oil outlet 1h to the lifting oil connecting piece 48b, which is connected to the nozzle valve piston lifting unit 48a.

Deaeration

Before testing the non-return valve 77, a deaeration of the valve 44 is performed:

1 . Connect the air bleed drain hose 54 to the air bleed stop valve 53 and lead the air bleed drain hose 54 to the oil injection chamber 59 through the drain hose hole 60.

2. Set the control/sealing oil valve 2 of the test system 1 to sealing position.

3. Close control oil pressure relief valve 4. 4. Increase sealing oil pressure up to 80 bar by use of control/sealing oil pressure control valve 8 and control/sealing oil pressure gauge 6 to lubricate or seal the plunger piston 58 and hydraulic piston 64.

5. Open the air bleed stop valve 53.

6. Close booster oil pressure relief valve 21 .

7. Close plunger oil pressure relief valve 11 .

8. Set plunger oil directional valve 10 to open position.

9. Increase plunger oil pressure up to 10-50 bar by use of plunger oil pressure control valve 12 and plunger oil pressure gauge 13.

Plunger oil will now flow through the plunger oil connection piece 49a through the cover plunger oil channel 63 to the plunger oil chamber 57a until all air has been bled from the plunger oil chamber 57a through the cover fluid channels 56c, 56b, 56a, the air bleed stop valve 53 and through the air bleed drain hose 54 into oil the injection chamber 59.

10. Check if any air bubbles are received in the injection chamber 59 via the air bleed drain hose 54.

11. When air bubbles are no longer received in the injection chamber 59 via the air bleed drain hose 54 then close air bleed stop valve 53.

12. Set the control/sealing oil valve 2 of the test system 1 to control position.

13. Set control oil directional valve 3 to open position.

14. Open constant oil valve 26.

15. Close control oil pressure relief valve 4.

16. Increase control oil pressure up to 10-50 bar by use of control/sealing oil pressure control valve 8 and control/sealing oil pressure gauge 6.

17. Apply the control oil to the control oil connecting piece 50 for 20 seconds.

By applying the control oil for 20 seconds at a pressure in the range of 10-50 bar, air will bleed from the hydraulic piston actuation chamber 65, which is formed above the hydraulic piston 64, through the control oil drain restriction 143b and the drain channels 143a, 142 through the constant oil port 129 and constant oil connecting piece and through the constant oil valve 26 into the oil tank 16.

Test of non-return valve 77 For this test the nozzle valve piston cut-off shaft 62 has to be hold in a lifted position from the nozzle valve connection seat 88 to keep the nozzle valve open.

1 . Increase lifting oil pressure up to 300 bar by use of lifting oil pressure control valve 28 and lifting oil pressure gauge 30. The lifting oil pressure relief valve 27 shall be closed.

2. Supply lifting oil at the pressure of 300 bar to the lifting oil connecting piece 48b. The lifting oil will now flow through the lifting oil channels 66 to the lifting piston 67, whereby the lifting piston 67 will be lifted to push up the nozzle valve piston cut-off shaft 62 a distance 68, which is about 2 mm, to keep the nozzle valve piston cut-off shaft 62 in the open position. The nozzle valve piston cut-off shaft 62 is connected to the hydraulic piston 64, which is pushed up the same distance.

3. Set the control/sealing oil valve 2 of the test system 1 to sealing position.

4. Close control oil pressure relief valve 4.

5. Increase sealing oil pressure up to 80 bar by use of control/sealing oil pressure control valves 8 and control/sealing oil pressure gauge 6 to lubricate or seal the plunger piston 58 and hydraulic piston 64.

6. Close booster oil pressure relief valve 21 .

7. Close plunger oil pressure relief valve 11 .

8. Set plunger oil directional valve 10 to open position.

9. Increase slowly plunger oil pressure up to 10-50 bar and then to 300 bar by use of plunger oil pressure control valve 12 and plunger oil pressure gauge 13.

This will slowly move the plunger piston 58 downwards until it is at the bottom of the plunger compression chamber 74.

10. Close the fuel oil pressure relief valve 32.

11. Increase fuel oil pressure up to 30 bar by use of fuel oil pressure control valves 33 and fuel oil pressure gauge 36, whereby the hydraulic accumulator 5 will be filled up.

12. Supply the fuel oil at the oil pressure of 30 bar to the fuel oil inlet connecting piece 47.

The fuel oil will now flow through fuel inlet channel 71 and into the suction one-way valve 70 through the suction valve inlet port 72, and from the suction one-way valve 70 via the plunger chamber supply channel 73 via the plunger piston fuel oil opening 57b and via the non-return valve supply channel 75 into the non-return valve 77.

If the non-return valve 77 is not tight, there will be a leakage at the non-return valve connection seat 76 and the fuel oil will flow through the nozzle valve chamber supply channels 78a, 78b, 79a, 79b, 80a, 80b to the nozzle valve chamber 81. From nozzle valve chamber 81 the fuel oil will then pass to the nozzle valve lower chamber 82, passing the lifted nozzle valve piston cut-off shaft 62 and into lifting unit fuel oil leakage channels 83, 84 and out into the oil injection chamber 59 via lifting unit fuel oil outlet 85.

13. Check if any oil drops or flow into the injection chamber 59 via the lifting unit fuel oil outlet 85.

14. Slowly increase the fuel oil pressure above 30 bar by use of fuel oil pressure control valve 33 and fuel oil pressure gauge 36 until the non-return valve 77 opens by observing droplets of oil or a running stream of oil from the lifting unit fuel oil outlet 85 into the oil injection chamber 59.

The non-return valve 77 holds the non-return valve spindle 86, which is pressed through the non-return valve connection seat 76 by the non-return valve spring 87b, and the nonreturn valve 77 opens when the fuel oil pressure operating on the non-return valve spindle 86 is larger than the pressure from the spring 87b.

15. Write down the observed opening pressure of the non-return valve 77.

16. Release the fuel oil pressure by opening the fuel oil pressure relief valve 32 and the fuel oil pressure control valve 33.

This will allow the non-return valve spindle 86 to properly close the non-return valve connection seat 76 to make a tight connection between the valve spindle 86 and the valve connection seat 76.

17. Increase the fuel oil pressure slowly by use of fuel oil pressure control valve 33 and fuel oil pressure gauge 36 to a pressure equal to the observed opening pressure of the non-return valve subtracted by 3-5 bar.

18. Let the fuel oil air driven pump fill up the hydraulic accumulator 5.

19. Check if any oil drops or flow into the injection chamber 59 via the lifting unit fuel oil outlet 85.

If any oil comes out the non-return valve is not tight. A few oil droplets are allowed, as it can be oil, which has not drained yet.

20. Turn off the fuel oil air driven pump 37 by use of fuel oil pressure control valve 33. 21. Wait 15 seconds to let the fuel oil pressure gauge 36 stabilize and write down the pressure.

22. Now using a stopwatch, wait 60 seconds and observe how much the pressure has fallen.

The non-return valve 77 has passed the test, if the pressure has not decreased more than 2 bar.

Test of the tightness of the nozzle valve piston cut-off shaft 62 against the nozzle valve connection seat 88

In this test the nozzle valve piston cut-off shaft 62 is in its normal operation mode without being constantly held in a lifted position from the nozzle valve connection seat 88.

1 . Open the lifting oil pressure relief valve 27 and the lifting oil pressure control valve 28 to release the lifting oil pressure.

By releasing the lifting oil pressure, the nozzle valve piston cut-off shaft 62 is released and will engage the nozzle valve connection seat 88 to hold a tight connection.

2. Apply fuel oil at a pressure of 5 bar higher than the observed opening pressure for the non-return valve 77.

Since the non-return valve 77 is open the fuel oil will fill up the nozzle valve chamber 81.

3. Check if any oil drops or flow into the injection chamber 59 via the lifting unit fuel oil outlet 85.

If the connection between the nozzle valve piston cut-off shaft 82 and the nozzle valve connection seat 88 is tight, no oil should be observed coming out from the lifting unit fuel oil outlet 85.

4. Open the fuel oil pressure relief valve 32 and the fuel oil pressure control valve 33 to release the fuel oil pressure.

5. Open the control oil pressure relief valve 4 and the control/sealing oil pressure control valve 8 to release the sealing oil pressure.

6. Close constant oil valve 26.

7. Open the plunger oil pressure relief valve 11 and the plunger oil pressure control valve 12 to release the plunger oil pressure.

8. Open booster oil pressure relief valve 21

9. Apply 80-100 bar of Nitrogen to the Nitrogen booster 21 via the gas inlet port 1a. 10. Close plunger oil directional valve 10 and plunger oil pressure relief valve 11 .

11. Build up pressure in the Nitrogen booster 21 to 150 bar by use of plunger oil pressure control valve 12 and plunger oil pressure gauge 13.

12. Increase sealing oil pressure up to 80 bar by use of control/sealing oil pressure control valve 8 and control/sealing oil pressure gauge 6 to lubricate or seal the plunger piston 58 and hydraulic piston 64.

13. Increase fuel oil pressure up to 30 bar by use of fuel oil pressure control valves 33 and fuel oil pressure gauge 36. The fuel oil pressure relief valve 32 has to be closed when increasing fuel oil pressure.

Since there is no pressure on top of the plunger piston 58, the fuel oil pressure through the suction on-way valve 70 will lift the plunger 58. When the plunger piston 58 is lifted to the top, the plunger compression chamber leakage channel 90 meets the plunger compression chamber leakage channel 91 , and fuel oil starts to leak from plunger compression chamber 74 through the plunger compression chamber leakage channels 89, 90 and 91 to fuel oil leakage outlet chamber 92. From the fuel oil leakage outlet chamber 92 the fuel oil flows to the function test sleeve fuel oil leakage outlet 93 and continuous to flow through the fuel oil drain sleeve 94 to the oil injection chamber 59.

The pressure for the nozzle valve piston cut-off shaft 62 is determined by the pressure working in the area between the nozzle valve connection seat 88 and the diameter of the nozzle valve piston guide 95. The opening pressure for the nozzle valve piston cut-off shaft 62, which is the pressure required to overcome the force from the nozzle valve spring 96, should be in the range of 388 - 447 bar. The hydraulic gearing of the piston plunger 58 is 2.47. Therefore, the corresponding pressure to open the nozzle valve piston cut-off shaft 62 from the pressure supplied to the plunger oil chamber 57a on top of the plunger piston 58 is between 157 - 181 bar.

14. Set the plunger oil directional valve 10 to open position to apply the plunger oil pressure accumulated in the Nitrogen booster 20 to the top of the plunger piston 58.

15. Check if any oil drop or flow into the oil injection chamber 59 via the lifting unit fuel oil outlet 85.

No oil should have been injected from the lifting unit port 85 into the oil injection chamber 59. Oil leakage between the plunger piston 58 and the pump barrel body 122 holding the plunger compression chamber 74 can be observed leaking into the oil injection chamber 59 through the plunger compression chamber leakage channels 91 , the fuel oil leakage outlet chamber 92, the function test sleeve fuel oil leakage outlet 93, and the fuel oil drain sleeve 94.

16. Close the plunger oil directional valve 10.

17. Build up pressure in the Nitrogen booster 21 to 155 bar by use of plunger oil pressure control valve 12 and plunger oil pressure gauge 13.

18. Set the plunger oil directional valve 10 to open position to apply the plunger oil pressure accumulated in the Nitrogen booster 20 to the top of the plunger piston 58.

19. Check if any oil drop or flow into the oil injection chamber 59 via the lifting unit fuel oil outlet 85.

20. Close the plunger oil directional valve 10.

Repeat test steps 17 to 20, while incrementally raising the plunger oil pressure by 5 bar: 160 - 165 - 170 - 175 - 180 - 185 bar. Observe at what plunger oil pressure the nozzle valve piston cut-off shaft 62 lifts and oil flows through the nozzle valve connection seat 88, into lifting unit fuel oil leakage channels 83 and 84 and out from lifting unit fuel oil outlet 85.

Write down the plunger oil pressure when the nozzle valve cut-off shaft 62 lifts from the connection seat 88 and oil flow from fuel oil outlet 85, convert the oil plunger pressure to the pressure inside the nozzle valve chamber 81 by multiplying the plunger oil pressure with the gearing ratio of 2.47. Write down this pressure.

Recheck the tightness of the cut-off shaft 62 against tightness the connection seat 88 by repeating steps 17 to 20 while supplying a plunger oil pressure to the top of the plunger piston 58 that is the opening pressure subtracted by 5-10 bar. Observe that no oil flows through the lifting unit fuel oil outlet 85. The acceptance criteria for this test is that the opening pressure is in the interval 155-185 bar.

Fuel injection sequence test

1 . Open the fuel oil pressure relief valve 32 and the fuel oil pressure control valve 33 to release the fuel oil pressure. 2. Open the control oil pressure relief valve 4 and the control/sealing oil pressure control valve 8 to release the sealing oil pressure.

3. Close plunger oil directional valve 10.

4. Close constant oil valve 26.

5. Set the control/sealing oil valve 2 to control position and set control oil directional valve 3 to open position

6. Close control oil pressure relief valve 4 and increase control oil pressure up to 300 bar by use of control/sealing oil pressure control valve 8 and control/sealing oil pressure gauge 6.

By supplying a control oil pressure of 300 bar on top of the hydraulic piston 64, this will keep the nozzle valve piston cut-off shaft 62 from opening.

7. Close plunger oil pressure relief valve 11. Build up pressure in the Nitrogen booster 21 to 300 bar by use of plunger oil pressure control valve 12 and plunger oil pressure gauge 13.

8. Close fuel oil pressure relief valve 32 and increase fuel oil pressure up to 30 bar by use of fuel oil pressure control valves 33 and fuel oil pressure gauge 36.

Since there is no pressure on top of the plunger piston 58, the fuel oil being inlet to the plunger compression chamber 74 through the suction one-way valve 70 will lift the plunger piston 58.

9. Open the plunger oil directional valve 10 to apply the boosted plunger oil pressure to the top of the plunger piston 58.

10. Check if any oil drop or flow into the oil injection chamber 59 via the lifting unit fuel oil outlet 85.

No oil should have been injected from the fuel oil outlet 85, because the control oil holds the hydraulic piston 64 down keeping the cut-off shaft 62 down as well.

11. Close plunger oil directional valve 10.

12. Build up pressure in the Nitrogen booster 21 to 300 bar by use of plunger oil pressure control valve 12 and plunger oil pressure gauge 13.

13. Check that the control/sealing oil valve 2 is set to control position and that the control oil directional valve is set 3 to open position.

14. Check that the control oil pressure is up to 300 bar.

15. Open the plunger oil directional valve 10 to apply the boosted plunger oil pressure to the top of the plunger piston 58.

16. Wait 1-2 seconds. 17. Close control oil directional valve 3.

The control oil directional valve 3 is a 3-way valve with two positions. When in closed position there is no fluid connection from the control/sealing oil valve 2 to control oil outlet 1d, but there is a fluid connection from the control oil outlet 1d to the oil tank 16. So, when the valve 3 is closed the pressure of control oil at port 1d is released, and when the valve 2 is in open position the oil flows from via valve 2 through valve 3 and there is a control oil pressure at control oil outlet 1d.

The fuel oil pressure in the nozzle valve chamber 81 can now lift the nozzle valve piston cut-off shaft 62.

18. Check if any oil drop or flow into the oil injection chamber 59 via the lifting unit fuel oil outlet 85.

An injection of oil into the oil injection chamber 59 should now has taken place.

19. Open control oil directional valve 3.

20. Increase control oil pressure up to 300 bar by use of control/sealing oil pressure control valve 8 and control/sealing oil pressure gauge 6.

21. Check if any oil drop or flow into the oil injection chamber 59 via the lifting unit fuel oil outlet 85.

No oil should have been injected from the fuel oil outlet 85, because the control oil holds the hydraulic piston 64 down keeping the cut-off shaft 62 down as well.

Repeat steps 1 to 21 a couple of times.

Test of suction one-way valve 70

The suction one-way valve 70 is tested indirectly.

1. Increase lifting oil pressure up to 300 bar by use of lifting oil pressure control valve 28 and lifting oil pressure gauge 30 with the lifting oil pressure relief valve 27 being closed, thereby supplying lifting oil at the pressure of 300 bar to the lifting oil connecting piece 48b.

The lifting oil will now flow through the lifting oil channels 66 to the lifting piston 67, whereby the lifting piston 67 will be lifted to push up the nozzle valve piston cut-off shaft 62 a distance 68, which is about 2 mm, to keep the nozzle valve piston cut-off shaft 62 in the open position. The nozzle valve piston cut-off shaft 62 is connected to the hydraulic piston 64, which is pushed up the same distance.

2. Increase slowly plunger oil pressure up to 10-50 bar and then to 300 bar by use of plunger oil pressure control valve 12 and plunger oil pressure gauge 13 with the plunger oil relief valve 11 and the booster oil relief valve 21 being closed and the plunger oil directional valve 10 being open. The plunger oil pressure relief valve 11 shall be closed when increasing the plunger oil pressure.

This will slowly move the plunger piston 58 downwards until it is at the bottom of the plunger compression chamber 74.

3. Increase slowly the fuel oil pressure above the observed open pressure of the nonreturn valve 77 by use of fuel oil pressure control valve 33 and the fuel oil pressure gauge 36 with the fuel oil pressure relief valve 32 being closed.

4. Check if any oil drop or flow into the oil injection chamber 59 via the lifting unit fuel oil outlet 85.

If the non-return valve 77 cannot be opened, then no oil is coming out from fuel outlet 85, which is a sign of that either the non- return valve spindle 86 or the spindle of the suction one-way valve 70 are stuck.

If during the test of the tightness of the nozzle valve piston cut-off shaft 62 against the nozzle valve connection seat 88 or during the fuel injection sequence test the needle of the fuel oil pressure gauge 36 rises up to 60 bar, then it is a sign that the valve seat of the suction one-way valve 70 is leaking.

Leakage detection test

The fully assembled injection valve 44 of Fig. 2 is exposed to a leakage detection test and placed in the detection valve holder 97a when performing the leakage detection test and supplied with air at 7 bar for detection of any leakages.

1 . Remove the injection valve 44 from the function test valve holder 45 and mount the atomizer union nut 126 and the atomizer 43 to obtain the fully assembled injection valve 44 of Fig. 2. Tighten the atomizer union nut 126 with recommended torque. The valve 44 to be tested now also holds the control oil connecting piece 50, the sealing oil connecting piece 51 , the plunger oil connecting piece 49a, the constant oil connecting piece 52, and air bleed stop valve 53.

2. Insert the assembled injector valve 44 in the detection test valve holder 97a and secure the valve 44 by tightening the connecting nuts 46d, see Fig. 27.

3. Connect the detection test hoses 98, 99, 100, 101 , 102, 103, 104, 105 and the non- return valves 109a -109h follows, see Fig. 29:

- Connect hose 98 with valve 109a, and valve 109a to control oil connecting piece 50.

- Connect hose 99 with valve 109b, and valve 109b to sealing oil connecting piece 51.

- Connect hose 100 with valve 109c, and valve 109c to constant oil connecting piece 52.

- Connect hose 101 with valve 109d, and valve 109d to DTS air outlet port II 113.

- Connect hose 102 with valve 109e, and valve 109e to DTS air outlet port III 112.

- Connect hose 103 with valve 109f, and valve 109f to DTS air outlet port 1 111.

- Connect hose 104 with valve 109g, and valve 109g to DTS lower air outlet port 110.

- Connect hose 105 with valve 109h, and valve 109h to DTS bottom air outlet port 114.

4. Plug the hole in plunger oil connecting piece 49b with plunger oil plug 115 and close the air bleed stop valve 53.

5. Insert all flexible hoses 98, 99, 100, 101 , 102, 103, 104, 105 into the detection test chamber 106 holding liquid.

The valve 108, see Figs. 28 and 29, is a detection test liquid drain valve to drain liquid from the bottom of the detection test valve holder 97a when needed.

7. Supply air at 7 bar into DTS air inlet port 107 and thereby into the detection sleeve 97a, see Fig. 28.

The compressed air will flow from air inlet port 107 through air inlet channel 195 to air inlet chamber 196, see Fig. 28.

From chamber 196 the air can flow to upper oil leakage outlet 166, through upper oil leakage channel 167 and intermediate leakage oil collecting channel 169 and intermediate leakage oil outlet 197 to intermediate outer leakage oil chamber 198, see Figs. 16 and 17. If any air leakage through sealing ring 199, see Fig. 16, the air will flow from DTS lower air outlet chamber 203 to DTS lower air outlet port 110, and then through valve 109 and hose 104 into the test liquid chamber 106. A leakage through the sealing ring 199 will be visible as bubbles in liquid chamber 106. If any leakage between the atomizer union nut 126 and the atomizer 43, the air will flow from air inlet chamber 196 through intermediate leakage oil outlet channel 197 and atomizer fuel oil leakage channel 168 to atomizer fuel oil leakage chamber 194 and then pass on to bottom air outlet chamber 204, see Figs 16 and 28. From chamber 204, the air passes through bottom air outlet port 114, valve 109h and hose 105 into the test liquid chamber 106. A leakage between union nut 126 and atomizer 43 will be visible as bubbles in liquid chamber 106.

If any leakage through barrel body outer sealing ring 209, the air will flow from air inlet chamber 196 to barrel body air outlet chamber I 210 to barrel body air outlet port 1 111 , and from port 111 through valve 109g and hose 104 into the test liquid chamber 106. A leakage will be visible as bubbles in liquid chamber 106.

From air inlet chamber 196 the air will flow to upper oil leakage outlet 166, through upper oil leakage channel 167 into intermediate upper leakage oil chamber 170. See Figs. 16 and 17. If any leakage through fourth intermediate upper sealing ring 175, see Fig. 18, the air will flow from chamber 170 to second control and sealing oil leakage channel 151 and pass on to first control and sealing oil leakage channel 150 to oil leakage outlet 158, see Fig. 7, and from outlet 158 to chamber 211 into barrel body air outlet port II 113, see Fig. 28. From port 113 through valve 109d and hose 10 into the test liquid chamber 106. A leakage through sealing ring 175 will be visible as bubbles in liquid chamber 106.

The compressed air will flow from air inlet chamber 196 to upper oil leakage outlet 166, through upper oil leakage channel 167 into upper oil leakage outlet 165 and into barrel body air outlet chamber III 212, see Figs. 16 and 28. If any leakage through second barrel body outer sealing ring 206, the air will flow from chamber III 212 to chamber II 211 and into air outlet port II 113. From port 113 through valve 109d and hose 10 into the test liquid chamber 106. A leakage through sealing ring 206 will be visible as bubbles in liquid chamber 106.

From air inlet chamber 196 the air will flow to upper oil leakage outlet 166, through upper oil leakage channel 167 into intermediate upper leakage oil chamber 170. See Figs. 16 and 17. If any leakage through fifth intermediate upper sealing ring 176, see Fig. 18, the air will flow from chamber 170 to the second fuel oil leakage channel 163 through third fuel oil leakage channel 164 into fuel leakage outlet 92, see Figs. 15 and 28. From leakage outlet 92 the air can flow to barrel body outlet port III 112 and through valve 109e and hose 102 into the test liquid chamber 106. A leakage through fifth intermediate upper sealing ring 176 will be visible as bubbles in liquid chamber 106.

The compressed air will flow from air inlet chamber 196 to upper oil leakage outlet 166, through upper oil leakage channel 167 into upper oil leakage outlet 165 and into barrel body air outlet chamber III 212, see Figs. 16 and 28. If any leakage through third barrel body outer sealing ring 207, the air will flow from chamber 212 to into fuel leakage outlet 92. From leakage outlet 92 the air can flow to barrel body outlet port III 112 and through valve 109e and hose 102 into the test liquid chamber 106. A leakage through third barrel body outer sealing ring 207 will be visible as bubbles in liquid chamber 106.

From air inlet chamber 196 the air will flow to upper oil leakage outlet 166, through upper oil leakage channel 167 into intermediate upper leakage oil chamber 170. See Figs. 16 and 17. If any leakage through third intermediate upper sealing ring 174, see Fig. 18, the air will flow from chamber 170 to sealing oil channel 133 and from channel 133 through sealing oil channels 132 and 131 to the sealing oil inlet port 128 and sealing oil connecting piece 51 , see Fig. 4. From connecting piece 51 through valve 109b and hose 99 into the test liquid chamber 106. A leakage through third intermediate upper sealing ring 174 will be visible as bubbles in liquid chamber 106.

From air inlet chamber 196 the air will flow to upper oil leakage outlet 166, through upper oil leakage channel 167 into intermediate upper leakage oil chamber 170. See Figs. 16 and 17. If any leakage through second intermediate upper sealing ring 173, see Fig. 18, the air will flow from chamber 170 to control oil drain channel 142 to constant oil inlet port 129 and constant oil connecting piece 52, see Fig. 5. From connecting piece 52 through valve 109c and hose 100 into the test liquid chamber 106. A leakage through second intermediate upper sealing ring 173 will be visible as bubbles in liquid chamber 106.

From air inlet chamber 196 the air will flow to upper oil leakage outlet 166, through upper oil leakage channel 167 into intermediate upper leakage oil chamber 170. See Figs. 16 and 17. If any leakage through first intermediate upper sealing ring 172, see Fig. 18, the air will flow from chamber 170 to control oil supply channel 140 to control oil inlet port 130 and control oil connecting piece 50, see Fig. 5. From connecting piece 50 through valve 109a and hose 98 into the test liquid chamber 106. A leakage through first intermediate upper sealing ring 172 will be visible as bubbles in liquid chamber 106.

8. Observe the test liquid chamber 106 for 2 minutes. If bubbles come out from one of the detection test hoses 98-105, it is a sign, that there is a leakage inside the injector valve 44. This test is accepted if no more than 2 bubbles 160 seconds is observed from each of hoses 98-105.

The invention has been described in conjunction with various embodiments herein.

However, other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality.