FUEL INJECTOR TECHNICAL FIELD

The present invention relates to a fuel injector adapted to be inserted in a well of an engine, the injector having a fuel inlet arranged in a position that is inside the well. BACKGROUND OF THE INVENTION

For arranging fuel injectors on an internal combustion engine, deep wells are arranged atop the engine block. Said well comprises a wide upward portion opening on the top of said engine head and, a narrow downward portion opening in a cylinder at the opposite end, said wide and narrow portions joining via a radial annular face against which abuts a positioning shoulder of the fuel injector inserted in said well. While the nozzle tip of the injector is arranged to spray fuel in the cylinder, at the opposite end, the head of the injector, where is arranged the fuel inlet, outwardly protrudes from the well. Fuel is received via a fuel lance having an extremity sealingly engaged in said fuel inlet, the lance height, that is the distance from the inlet to said positioning shoulder, being in a bespoke position based on the architecture of the engine manufacturer. Entry of the fuel closer to the nozzle would be preferred.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to resolve the above mentioned problems in providing a fuel injector having an elongated shape comprising an actuator assembly and a nozzle assembly, said injector being adapted to be arranged in a well provided on an internal combustion engine wherein, the injector is provided with a fuel inlet arranged in the nozzle assembly that, in use, is inserted inside the well, only an end of an actuator assembly of said injector protruding outside the well.

In a further aspect of the invention, the inlet may define a female seating face adapted to complementary receive a fuel lance extremity male face.

Opposite the inlet may be provided a force reaction member arranged to be in contact against the face of the well. Said force reaction member may be a bump integral to the injector.

Alternatively, said force reaction member may be an independent member inserted between said the injector and the face of the well.

The nozzle assembly of the fuel injector may have a body within which a valve member is guided between a lower guide, defined in a tip member, and an upper guide, defined in an upper member, the body further comprising a barrel member arranged between said tip member and said upper member, the inlet being defined in said barrel member.

The fuel injector may further comprise an upper capnut fixing the barrel member to said actuator portion of the fuel injector.

The inlet may be defined in a portion of a barrel member outer face uncovered by said upper capnut.

The fuel injector may further comprise a lower capnut fixing the tip member to said the barrel member.

The inlet may be defined in a portion of a barrel outer face uncovered by said lower capnut.

At an end, said lower capnut extends from an under face adapted to be in contact to the bottom of the well, said inlet being between 12 mm and 20 mm preferably 15mm away from said under face.

The invention further extends to a fuel injection equipment adapted to be arranged on an internal combustion engine, said equipment comprising at least one injector as previously described.

The invention further extends to internal combustion engine provided with such a fuel injection equipment.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is now described by way of example with reference to the accompanying drawings in which:

Figure 1 shows an injector as per the invention, represented in axial section and arranged on an internal combustion engine.

Figure 2 is a portion of figure 1 magnifying a nozzle portion of the injector. DESCRIPTION OF THE PREFERRED EMBODIMENTS

In reference to the figures is presented a portion of an internal combustion engine 2 provided with an injector well 4 downwardly extending from an opening in the engine top face to an opening in a compression chamber.

As presented on figure 1, an injector 8 inserted in said well 4 upwardly protrudes outside the well 4 and has its opposite fuel spray end flushing outside the well 4 inside said compression chamber. Moreover, a fuel lance 6 radially arranged through a channel of the engine block is, at an extremity, complementary connected to a fuel inlet 10 of the injector 8.

The injector 8 extends along a main axis X and, using the arbitrary and non-limiting top-down orientation of the figure, said injector 8 comprises an upper actuator assembly 12, a central control valve assembly 14 and a bottom nozzle assembly 16 firmly maintained against each other by a first capnut 18, or lower capnut 18, fixing the thin member 46 to the lower end of the barrel 44 and, a second capnut 20, or upper capnut 20, fixing the upper part of the barrel 44 to the actuator assembly 14.

Arranged in the well 4, the injector 8 is positioned in place by having an under face 19 of the lower capnut 18 against a shoulder 5 of the well, a washer being interposed between said two faces.

More precisely, the actuator assembly 12 has a body 22 axially X extending from a head portion 24 where is arranged an electrical connector 26 to, a transverse under face 28 in which opens an inner bore 30 wherein is arranged a solenoid 32 electrically connected to said connector 26.

The control valve assembly 14 has a cylindrical body 34 extending from an upper face 36 in sealing contact against said actuator under face 28 to an opposed under face 38, said valve body 34 being provided with a hydraulic bore upwardly opening in an armature chamber and, wherein an armature-and-spool assembly 40 cooperates with the solenoid 32. The armature is a thick disc-like member occupying said chamber and, the spool is a stem in slide-fit adjustment in the hydraulic bore.

The nozzle assembly 16 comprises an upper member 42 adjusted atop a barrel member 44, itself atop a thin tip member 46, said three members defining together an inner space S wherein a needle valve member 48 is axially X guided between upper guiding means defined in the upper member 42 and lower guiding means defined in the thin tip member 46. Furthermore, a spring 50 compressed between a seat integral to the needle and the upper member 42 permanently urges the needle 48 toward a closed position where fuel injection is prevented.

More precisely, the upper member 42 has a large cylindrical portion 52 atop a narrower positioning portion 54 inserted and adjusted in an upper recess 56 defined in the top end of the barrel member 44.

The barrel member 44 upwardly extends in a peripheral wall 58 which inner face partly defines said recess 56 and which outer face 60 comprises a cylindrical portion and a small annular shoulder 62 radially inwardly extending to a main barrel cylindrical outer face 64.

The upper capnut 20 is a tubular member internally threaded and tightened at an upper end around the lower part of the outer face of the actuator member and, defining at a lower end an annular shoulder face 66 in

complementary contact against the barrel small annular shoulder 62. Alternatively to a threaded interface, the upper capnut 20 can be attached to the actuator member by other means such as rolling or swaging. As the upper capnut 20 is tightened, the control valve 14 and the upper member 42 are compressed inside the capnut 20 between the actuator member and the barrel member.

At the opposite extremity, the barrel member 44 defines another recess

68, or lower recess 68, surrounded by another peripheral wall 70 externally threaded while, in said recess 68 is received and adjusted the upper end of the thin tip member 46.

The thin tip member 46 is axially X upwardly pressed against the barrel member 44 by the lower capnut 18 which on one end abuts an outer shoulder 72 of the thin member and, on the other end, is tightened onto said externally threaded portion of the barrel member. The lower capnut 18 further defines the under face 19 that is a positioning reference inside a well of an engine block.

As it is visible, the majority of the barrel member 44 is between said capnuts 18, 20 and, in said uncovered central portion is defined the fuel inlet 10 extending through the peripheral wall of the barrel and opening in inner space S that surrounds the needle valve member 48. Said inlet 10 defines a sloped seating face 74 reducing in section against which, in use, comes in complementary sealing abutment a male end face of the fuel lance 6.

Thanks to said two-capnut arrangement, the inlet 10 is arranged in the close vicinity to the lower capnut 18, as shown on the figures or, can be arranged in any other part of the barrel, depending of the internal combustion engine architecture.

Furthermore, to compensate for the force of the lance 6 that radially pushes the injector 8, a force reaction member 76 is arranged right opposite the inlet 10, between the barrel 44 and the side wall of the well 4. Said force reaction member 76 fills the gap between the well 4 and the barrel 44. It can be integral to the barrel forming a local bump, as represented on the figures or, it can be a separate part bonded to the barrel. Thanks to said force reaction member 76, the injector position does not change as the fuel lance radially pushes the barrel in order to ensure a sealing contact at the inlet.

LIST OF REFERENCES

X mam axis

S inner space

2 internal combustion engine

4 injector well

5 shoulder

6 fuel lance

8 fuel injector

10 fuel inlet

12 actuator assembly

14 control valve assembly

16 nozzle assembly

18 lower capnut

19 under face of the lower capbut

20 upper capnut

22 body of the actuator

24 head portion of the actuator

26 electrical connector

28 under face of the actuator body

30 bore

32 solenoid

34 valve body 36 upper face of the valve

38 under face of the valve

40 armature-and-spool assembly

42 upper member

44 barrel member

46 thin tip member

48 needle valve member

50 spring

52 large cylindrical portion of the upper member

54 narrower positioning portion of the barrel member

56 upper recess

58 peripheral wall

60 outer face

62 shoulder

64 main outer face of the barrel member

66 annular shoulder face

68 lower recess

70 peripheral wall of the lower recess

72 outer shoulder

74 sloped seating face of the inlet

76 force reaction member