COMBUSTION ENGINE

BACKGROUND

[0001] For today's internal combustion engines, variable valve timing (WT) is the process of altering the timing of a valve lift event, which is often used to advantageously improve performance, fuel economy, and/or emissions. WT is increasingly being used in combination with variable valve lift systems. There are many ways in which synergies with WT can be achieved, ranging from mechanical devices to electro-hydraulic and camless systems. Further, increasingly strict emissions regulations are causing many automotive manufacturers to consider WT systems State of the art variable valve adjustment.

[0002] As, valves within an internal combustion engine are used to control the flow of the intake and exhaust gases into and out of the combustion chamber. The timing, duration and lift of these valve events can have a significant impact on engine performance. Therefore, without variable valve timing or variable valve lift, the valve timing must be the same for all engine speeds and conditions, engine performance compromises are necessary. It is recognized that advantageously, an engine equipped with a WT actuation system provides for engine performance to be improved over the engine operating range.

[0003] Unfortunately, current state of the art WT systems require complicated mechanical architectures and/or complex electrical control systems to effect and maintain WT during operation of today's modern engines. For example, one factor preventing WT technology from wide use in production automobiles is the ability to produce a cost effective means of controlling the valve timing under the conditions internal to the engine. For example, engine operating at 3000 revolutions per minute will rotate the camshaft 25 times per second, so the valve timing events have to occur at precise times to offer the desired performance benefits. Electromagnetic and pneumatic camless valve actuators can offer the greatest control of precise valve timing, but are currently not cost effective for production vehicles. Other examples of overly complex mechanical configuration for WT can include: cam phasing; cam oscillation; eccentric cam drive; three dimensional cam lobe; and two shaft combined cam lobe profile.

SUMMARY

[0004] It is an object of the present invention to provide a variable hydraulic timing device to obviate or mitigate at least one of the above-presented disadvantages.

[0005] A first aspect provided is a hydraulic device comprising: a housing; a first piston bore in the housing having a drive piston positioned therein for reciprocation along a first axis of the first piston bore; a second piston bore in the housing having a driven piston positioned therein for reciprocation along a second axis of the second piston bore, the first piston bore in fluid communication with the second piston bore; a first resilient element for resisting movement of the driven piston when the drive piston is moving towards the driven piston; a third piston bore in the housing having a floating piston positioned therein for reciprocation along a third axis of the third piston bore; a second resilient element in the third piston bore for resisting movement of the floating piston when the drive piston is moving towards the driven piston; a fluid passageway connecting at least one of the first piston bore and the second piston bore to the third piston bore for providing communication of hydraulic fluid between the at least one of the first piston bore and the second piston bore with the third piston bore; a fourth piston bore positioned along the fluid passageway between the third piston bore and the at least one of the first piston bore and the second piston bore, the fourth piston bore having a shuttle piston positioned therein for reciprocation along a fourth axis of the fourth piston bore; and a third resilient element in the fourth piston bore for resisting movement of the shuttle piston when the drive piston is moving towards the driven piston.

[0006] A second aspect provided is a hydraulic device comprising: a housing; a first piston bore in the housing having a drive piston positioned therein for reciprocation along a first axis of the first piston bore; a second piston bore in the housing having a driven piston positioned therein for reciprocation along a second axis of the second piston bore, the first piston bore in fluid communication with the second piston bore; a third piston bore in the housing having a floating piston positioned therein for reciprocation along a third axis of the third piston bore; a second resilient element in the third piston bore for resisting movement of the floating piston when the drive piston is moving towards the driven piston; a fluid passageway connecting at least one of the first piston bore and the second piston bore to the third piston bore for providing communication of hydraulic fluid between the at least one of the first piston bore and the second piston bore with the third piston bore; and a fourth piston bore positioned along the fluid passageway between the third piston bore and the at least one of the first piston bore and the second piston bore, the fourth piston bore having a shuttle piston positioned therein for reciprocation along a fourth axis of the fourth piston bore.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The foregoing and other aspects will now be described by way of example only with reference to the attached drawings, in which:

[0008] Figure 1 is a cross sectional view of a piston cylinder arrangement of a hydraulic device coupled to an internal combustion engine;

[0009] Figure 2 is an operational example of the hydraulic device shown in Figure

1 ;

[0010] Figure 3 shows is a further operational example of the hydraulic device shown in Figure 1 ;

[0011] Figure 4 is a further operational example of the hydraulic device shown in Figure 1 ;

[0012] Figure 5 is a further operational example of the hydraulic device providing valve opening for the device of Figure 1 ;

[0013] Figure 6 is an alternative embodiment of the device of Figure 1 ;

[00 4] Figure 7 is a further alternative embodiment of the device of Figure 1 ;

[0015] Figure 8 is an alternative embodiment of the device of Figure 1 and Figure

7; [0016] Figures 9-14 show operational examples of the device of Figure 8;

[0017] Figure 5 is an alternative embodiment of the device of Figure 8;

[0018] Figure 6 is an alternative embodiment of Figure 8; and

[0019] Figure 17 is a further alternative embodiment of Figure 8.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0020] Referring to Figure 1 , shown is a hydraulic device 40 having a housing 42 defining a bore 44 containing a plurality of sequential chambers 3,5,7 separated by a floating piston 4 between a first chamber 3 and a second chamber 5, and a driven piston 46 between the second chamber 5 and a third chamber 7. Opposite to the floating piston 4 is a drive piston 2 defining the first chamber 3 there between. Opposite to the floating piston 4 is the driven piston 46 defining the second chamber 5 there between. Opposite to the driven piston 46 is a bore head 45 (of the bore 44) defining the third chamber 7 there between. As such, reciprocation 48 of the drive piston 2 in the bore 44 (for example in communication with a push rod 50 driven by a cam 1) is coupled to reciprocation 49 of the floating piston 4 in the bore 44 and reciprocation 51 of the driven piston 46 in the bore 44, as further described below. The cam 1 can be attached to a rotating shaft 52 such as a cam shaft of an engine 53. Seals 24 are provided as shown. A valve guide 8 is shown for stem push rod 6 which couples motion 51 of the driven piston 46 with the valve 11 via stem 10, in the case where the hydraulic device is utilized as a timing component for a inlet/outlet valve 11 opening/closing of the combustion engine 53. Also included can be a heat shield 9 for shielding the bore 42 from heat generated in the combustion chamber 62 of the engine cylinder 62. Also included is a oil gallery 12 for circulating lubricating/cooling oil to the seals 69 and head 45, as desired. Also included is a stop 70 defining for limiting travel of the driven piston 46 within the bore 42 towards the floating piston 4, recognizing that the bore head 45 can define the limit of travel for the driven piston 46 along the bore 42 axis opposite the stop 70. Also included can be an air breather port 23 between ambient and the drive piston 2. Reference numeral 26 exemplifies axial position of the floating piston for different initial pressures of the hydraulic fluid in the second chamber 5 as controlled by the hydraulic circuit 29. It is recognized that the greater the initial pressure of the hydraulic fluid in the second chamber, the closer the floating piston 4 is positioned to the drive piston 2 when at BDC (Bottom Dead Center). As such, travel required by the drive piston 2 towards the floating piston 4 (away from BDC) is less for the initial higher pressures than for initial lower pressures, in order to compress the low pressure fluid in the first chamber 3 to raise the pressure of the compressible fluid in the first chamber 3 to the set pressure of the third chamber 7 and the pressure of the hydraulic fluid in the second chamber 5 from the initial pressure to the set pressure of the third chamber 7. It is recognized that driven piston 46 can remain stationary against stop 70 until the pressures in chambers 3,5 equalize with the set pressure in the third chamber 7. As further discussed below, once the pressures in the chambers 3,5,7 are equalized, due to travel of the drive piston 2 away from BDC, further travel of the drive piston 2 away from BDC will cause movement of all three pistons 2,4,6 simultaneously towards the bore head 45, which will cause movement of a valve 11 with respect to a valve seat 54 and a rise in pressures in the chambers 3,5,7 higher than the initial set pressure in the third chamber 7.

[0021] The hydraulic device 40 is also coupled to the valve 11 via valve stem 10, whereby the valve 11 is configured for seating within the valve seat 54 of cylinder head 27 of the engine 53. An example configuration of the engine cylinder 56 can be a cylinder bore 58 coupled to the cylinder head 27, a piston 60 contained within the bore 58 for reciprocation therein, a combustion chamber 62 situated between the piston 60 and the cylinder head 27 and an inlet port 64 and outlet port 66 in fluid communication with the valve seat 54 defining an entrance (for fuel) and exit (for combustion products) for the combustion chamber 62. It is recognized that when the valve 11 is positioned in the valve seat 54 as shown, the valve 11 is considered in the closed position thus inhibiting fluid communication between the ports 64,66 and the combustion chamber 60. Referring to Figure 2, the valve 11 is shown in the open position.

[0022] Referring again to Figure 1 , the hydraulic device 40 has first chamber 3 filled with a low pressure (e.g. 25 psi) compressible fluid via in-out port 25. The third chamber 7 is filled with a high pressure (e.g. 250 psi) compressible fluid via in-out port 28, such that the low pressure is less than the high pressure (e.g. by an order of magnitude). The second chamber 5 is supplied via hydraulic circuit 29 with incompressible (e.g. hydraulic oil) fluid via in-out port 67. The hydraulic fluid supply is coordinated via a pump 18 to and from a reservoir 17 via a plurality of control elements 13,14,15,16,19,20,21 (e.g. valves, conduits, etc.), with respect to the second chamber 5.

[0023] In operation of the hydraulic device 40, first hydraulic oil is injected into the second chamber 5 via hydraulic circuit 29 to a selected pressure (e.g. 40 psi in figure 2). Reciprocation 48 of drive piston 2 (under influence of cam 1 and resulting motion of pushrod 50) from BDC towards the cylinder head 45 will cause travel of the drive piston 2 to decrease the volume of the first chamber 3 (i.e. decrease axial bore distance between pistons 2,4) until pressure of the compressible fluid in the chambers 3,5 reach that of the compressible fluid set in the third chamber 7 (e.g. 200 psi). Once pressures of the chambers 3,5 and third chamber 7 are equalized, reciprocation 48,49,51 will be synchronous as further travel of the drive piston 2 will drive both the floating piston 4 and the driven piston 46. Any movement of the driven piston 6 away from stop 70 will cause opening of the valve 11 from the closed position to the open position (shown in ghost view), as well as an increase in the pressure of the chambers 3,5,7 to higher than the set pressure of the third chamber 7. Once the valve 11 is open, combustion gases can flow from the chamber 62 via outlet 66 or air-fuel injection can flow into the combustion chamber 62 via inlet 64, depending upon the operational state (e.g. intake, exhaust) of the engine 53. It is recognized that timing of the valve 11 opening is delayed until travel of the drive piston 2 causes pressure of the chambers 3,5 to reach that of the third chamber 7, such that initial pressure (e.g. when drive piston is at BDC) of the compressible fluid in the first chamber 3 is set by the pressure of the hydraulic fluid injected into the second chamber 5 by the hydraulic circuit 29. It is also recognized that ejection of hydraulic fluid from the second chamber 5 back to the reservoir 17 can be facilitated by open/close states of valves of the circuit 29 and travel of the floating piston 4 as influenced by the pressure of the compressible fluid in the first chamber 3.

[0024] Referring to Figure 3, hydraulic fluid is injected into the second chamber 5 at a higher pressure (e.g. 150 psi) by the hydraulic circuit 29, which results in movement of the floating piston 4 towards the drive piston 2 sitting at BDC, for example. As can be seen by comparison with Figure 2, the axial separation X of the driven piston 2 and the floating piston 4 is greater for the lower pressure (e.g. 40 psi) than compared to the higher pressure (e.g. 150 psi) of the injected hydraulic fluid into the second chamber 5. A result of this difference in separation X is that travel 48 of the driven piston 2 in Figure 3, to cause increase in the first chamber 3 fluid pressure to that of 200 psi (that set in third chamber 7), is less than travel 48 needed of the driven piston 2 in Figure 2. In other words, retardation or delay of the valve 11 opening is less for higher injection pressures of hydraulic fluid in the second chamber 5 and resulting initial first chamber 3 pressure.

[0025] Referring to Figure 4, hydraulic fluid is injected into the second chamber 5 at a pressure equal to the set pressure of the third chamber 7 (e.g. 200 psi) by the hydraulic circuit 29, which results in movement of the floating piston 4 towards the drive piston 2 sitting at BDC, for example. As can be seen by comparison with Figures 2 and 3, the axial separation X of the driven piston 2 and the floating piston 4 is less for the equalized pressure (e.g. 200 psi) than compared to the other lower pressures (e.g. 40, 150 psi) of the injected hydraulic fluid into the second chamber 5. It is recognized that the separation distance X can approach zero when the first chamber 3 and third chamber 7 pressure are equal before movement of the drive piston 2 (e.g. away from BDC). As such, any travel 48 of the drive piston 2 away from the initial starting point (e.g. BDC) will result in simultaneous reciprocation (48,49,51 are approximately equal) of the floating piston 4 and the driven piston 46 in conjunction with the drive piston 2, as well as an increase in the pressure of the third chamber 7 to higher than the set pressure. In other words, retardation or delay of the valve 1 opening is removed when injection pressures of hydraulic fluid into the second chamber 5 and resulting initial chamber 3 pressure equal that of the set pressure in the third chamber 7. As such, movement of the drive piston 2 in Figure 5 from BCD to TDC caused movement of the floating piston 4, the driven piston 46, the stem rod 6, the valve stem 10 and valve 1 , in order to move the valve 11 from the closed position to the open position as shown.

[0026] In terms of Figures 2,3,4, the position of the floating piston 4, once the hydraulic fluid pressure of the second chamber 5 is set (by the hydraulic circuit 29), determines the degree of advance or retardation of valve 11 timing. This is recognized in conjunction with positioning of the cam 1 with respect to the piston rod 50 is synchronized (by desired design) with the positioning of the floating piston 4 according to hydraulic fluid pressure in the second chamber 5 (when the drive piston is at BDC). For example, Figure 2 provides an example degree of valve retardation due to positioning of the floating piston 4 with respect to the drive piston 2 when at BDC, recognizing that the drive piston 2 must travel from BDC (as driven by the cam 1) towards the bore head 45 a set distance D1 before the pressure of the compressible fluid in the first chamber 3 increases from the initial pressure (e.g. 40 psi) to the set pressure (e.g. 200 psi) of the third chamber 7. Once the pressures are equalized, further travel of the drive piston 2 will cause travel of the driven piston 46 and opening of the valve 11. Alternatively, for example, Figure 3 provides a lack of valve retardation due to positioning of the floating piston 4 with respect to the drive piston 2 when at BDC, recognizing that the drive piston 2 must travel from BDC (as driven by the cam 1) towards the bore head 45 a set distance D2 before the pressure of the compressible fluid in the first chamber 3 increases from the initial pressure (e.g. 40 psi) to the set pressure (e.g. 200 psi) of the third chamber 7. It is recognized that distance D2 is less than distance D1 and once the pressures are equalized further travel of the drive piston 2 will cause travel of the driven piston 46 and opening of the valve 11. In this example, travel D2 can be designed into the system such that the equivalent rotation of the cam 1 is needed to have the valve 11 opening "on time". Alternatively, for example, Figure 4 provides an advance valve timing due to positioning of the floating piston 4 with respect to the drive piston 2 when at BDC, recognizing that when the drive piston 2 begins travel from BDC (as driven by the cam 1) towards the bore head 45, the pressure of the compressible fluid in the first chamber 3 is already at the set pressure (e.g. 200 psi) of the third chamber 7. It is recognized that since the pressures are equalized, further travel of the drive piston 2 will cause travel of the driven piston 46 and opening of the valve 11. In this example, travel can be designed into the system such that the equivalent rotation of the cam 1 is needed to have the valve 11 opening "in advance".

[0027] Referring to Figure 6, shown is an alternative embodiment of the hydraulic device 40 of Figure 1 , such that the low pressure compressible fluid is in the second chamber 5 and the hydraulic fluid of the hydraulic circuit 29 is in the first chamber 3. Also included can be an inlet/outlet port 23 between the first chamber 3 and the hydraulic circuit 29. As such, similar to what was presented above, once the pressure of the compressible fluid in the second chamber 5 is set by injection of the hydraulic fluid by the hydraulic circuit 29 into the first chamber 3, travel 48 of the drive piston 2 will cause travel of the floating piston 4 until the pressure of the second chamber 5 matches the set pressure of third chamber 7. Once matched, further travel 48 of the drive piston 2 will cause travel of the driven piston 46 away from stop 70 and towards head 45 in order to open the valve 11.

[0028] Reference numeral 26 exemplifies axial position of the floating piston for different initial pressures of the hydraulic fluid in the first chamber 3 as controlled by the hydraulic circuit 29. It is recognized that the greater the initial pressure of the hydraulic fluid in the second chamber, the closer the floating piston 4 is positioned to the driven piston 46 when the drive piston 2 is at BDC (Bottom Dead Center). As such, travel required by the drive piston 2 towards the floating piston 4 (away from BDC) is less for the initial higher pressures than for initial lower pressures, in order to compress the low pressure fluid in the second chamber 5 to raise the pressure of the compressible fluid in the second chamber 5 to the set pressure of the third chamber 7 and the pressure of the hydraulic fluid in the first chamber 3 from the initial pressure to the set pressure of the third chamber 7. It is recognized that driven piston 46 can remain stationary against stop 70 until the pressures in chambers 3,5 equalize with the set pressure in the third chamber 7. As further discussed below, once the pressures in the chambers 3,5,7 are equalized, due to travel of the drive piston 2 away from BDC, further travel of the drive piston 2 away from BDC will cause movement of all three pistons 2,4,6 simultaneously towards the bore head 45, which will cause movement of a valve 11 with respect to a valve seat 54 and a rise in pressures in the chambers 3,5,7 higher than the initial set pressure in the third chamber 7.

[0029] Referring again to Figure 6, in operation of the hydraulic device 40, first hydraulic oil is injected into the first chamber 3 via hydraulic circuit 29 to a selected pressure (e.g. 50 psi). Reciprocation 48 of drive piston 2 (under influence of cam 1 and resulting motion of pushrod 50) from BDC towards the cylinder head 45 will cause travel of the drive piston 2 to decrease the volume of the second chamber 5 (i.e. decrease axial bore distance between pistons 4,6 by moving the floating piston 4 towards the bore head 45) until pressure of the compressible fluid in the second chamber 5 reaches that of the compressible fluid set in the third chamber 7 (e.g. 200 psi). Once pressures of the chambers 3,5 and third chamber 7 are equal, reciprocation 48,49,51 will be synchronous as further travel of the drive piston 2 will drive both the floating piston 4 and the driven piston 46. Any movement of the driven piston 46 away from stop 70 will cause opening of the valve 1 1 from the closed position to the open position (shown in ghost view in Figure 1), as well as an increase in the pressure of the chambers 3,5,7 to higher than the set pressure. Once the valve 11 is open, combustion gases can flow from the chamber 62 via outlet 66 or air-fuel injection can flow into the combustion chamber 62 via inlet 64, depending upon the operational state (e.g. intake, exhaust) of the engine 53 (see Figure 1). It is recognized that timing of the valve 1 1 opening is delayed until travel of the drive piston 2 causes pressure of the chambers 3,5 to reach that of the third chamber 7, such that initial pressure (e.g. when drive piston 2 is at BDC) of the compressible fluid in the second chamber 5 is set by the pressure of the hydraulic fluid injected into the first chamber 3 by the hydraulic circuit 29. It is also recognized that ejection of hydraulic fluid from the first chamber 3 back to the reservoir 17 can be facilitated by open/close states of valves of the circuit 29 and travel of the floating piston 4 as influenced by the pressure of the compressible fluid in the second chamber 5.

[0030] Shown in Figure 7 is an alternative embodiment of the hydraulic device 40 of Figure 1. Connected to stem rod 6 is a fuel injector valve 32 for opening or closing fuel injector port 33 in fluid communication with the injection port 64 and cylinder 58 shown in Figure 1 , providing the case where the hydraulic device 40 is utilized as a timing component for an injector valve 32 opening/closing for the combustion engine 53. Pressurized lines 31 ,34 can be used to supply fuel under pressure to the injector valve 32 as desired. In one example, the fuel can be supplied via supply port 76 and pumped via reciprocation of drive piston 2 using a series of check valves 36,37 and fuel lines 35,39 between the supply port 76 and the fuel injector valve 32. [0031] Reference numeral 26 exemplifies axial position of the floating piston for different initial pressures of the hydraulic fluid in the second chamber 5 as controlled by the hydraulic circuit 29. It is recognized that the greater the initial pressure of the hydraulic fluid in the second chamber, the closer the floating piston 4 is positioned to the drive piston 2 when at BDC (Bottom Dead Center). As such, travel required by the drive piston 2 towards the floating piston 4 (away from BDC) is less for the initial higher pressures than for initial lower pressures, in order to compress the low pressure fluid in the first chamber 3 to raise the pressure of the compressible fluid in the first chamber 3 to the set pressure of the third chamber 7 and the pressure of the hydraulic fluid in the second chamber 5 from the initial pressure to the set pressure of the third chamber 7. It is recognized that driven piston 46 can remain stationary against stop 70 until the pressures in chambers 3,5 equalize with the set pressure in the third chamber 7. As further discussed below, once the pressures in the chambers 3,5,7 are equalized, due to travel of the drive piston 2 away from BDC, further travel of the drive piston 2 away from BDC will cause movement of all three pistons 2,4,6 simultaneously towards the bore head 45, which will cause movement of a valve 32 with respect to a injector port 33 and a rise in pressures in the chambers 3,5,7 higher than the initial set pressure in the third chamber 7. It is recognized that the hydraulic device 40 of Figure 7 can also be configured similarly to that of the device of Figure 6 in terms of ordering of the chambers 3,5,7 (i.e. hydraulic fluid followed by low pressure compressible fluid followed by high pressure compressible fluid).

[0032] Referring again to Figure 7, the hydraulic device 40 has the first chamber 3 filled with a low pressure (e.g. 25 psi) compressible fluid via in-out port 38. The third chamber 7 is filled with a high pressure (e.g. 250 psi) compressible fluid via in-out port 28, such that the low pressure is less than the high pressure (e.g. by an order of magnitude). The second chamber 5 is supplied via hydraulic circuit 29 with incompressible (e.g. hydraulic oil) fluid via in-out port 67. The hydraulic fluid supply is coordinated via a pump 18 to and from the reservoir 17 via a plurality of control elements 13,14,15,16,19,20,21 (e.g. valves, conduits, etc.), with respect to the second chamber 5. [0033] In operation of the hydraulic device 40, first hydraulic oil is injected into the second chamber 5 via hydraulic circuit 29 to a selected pressure (e.g. 40 psi in figure 2). Reciprocation 48 of drive piston 2 (under influence of cam 1 and resulting motion of pushrod 50) from BDC towards the bore head 45 will cause travel of the drive piston 2 to decrease the volume of the first chamber 3 (i.e. decrease axial bore distance between pistons 2,4) until pressure of the compressible fluid in the first chamber 3 and pressure of the hydraulic fluid in the second chamber 5 reach that of the compressible fluid set in the third chamber 7 (e.g. 200 psi). Once pressures of the chambers 3,5 and the third chamber 7 are equal, reciprocation 48,49,51 will be synchronous as further travel of the drive piston 2 will drive both the floating piston 4 and the driven piston 46. Any movement of the driven piston 6 away from stop 70 will cause opening of the valve 32 from the closed position to the open position, as well as an increase in the pressure of the third chamber 7 to higher than the set pressure. Once the valve 32 is open, pressurized fuel can flow into the chamber 62 of the engine 53 (see Figure 1). It is recognized that timing of the valve 32 opening is delayed until travel of the drive piston 2 causes pressure of the chambers 3,5 to reach that of the third chamber 7, such that initial pressure (e.g. when drive piston 2 is at BDC) of the compressible fluid in the first chamber 3 is set by the pressure of the hydraulic fluid injected (represented by numeral 26) into the second chamber 5 by the hydraulic circuit 29. It is also recognized that ejection of hydraulic fluid from the second chamber 5 back to the reservoir 17 can be facilitated by open/close states of valves of the circuit 29 and travel of the floating piston 4 as influenced by the pressure of the compressible fluid in the first chamber 3.

[0034] Referring to Figure 8, shown is an alternative embodiment of the hydraulic device 40 of Figures 1 and 7. The hydraulic device 40 having the housing 42 defining the bore 44a, b (separated into the first bore 44a and the second bore 44b by a passageway 100 providing fluid communication between the bores 44a, b) containing the plurality of chambers 3a,b,5,7. In terms of the chambers 3a,b,5,7, these are separated for example by the floating piston 4 between the first chamber portion 3b and the second chamber 5, and the driven piston 46 between the first chamber portion 3a and the third chamber 7. Fluidly opposite to the floating piston 4 (via the passageway 00) is the drive piston 2 defining the first chamber portions 3a,b there between. Fluidly opposite to both the floating piston 4 (via chambers 3a,b) and the drive piston 2 (via chamber 3a) is the driven piston 46. Opposite to the driven piston 46 is the bore head 45 (of the bore 44a) defining the third chamber 7 there between. Opposite to the floating piston 4 is the bore head 45 (of the bore 44b) defining the second chamber 5 there between.

[0035] As such, reciprocation 48 of the drive piston 2 in the bore 44a (for example in communication with the push rod 50 driven by the cam 1 is coupled to reciprocation 49 of the floating piston 4 in the bore 44b and reciprocation 51 of the driven piston 46 in the bore 44a, as further described below. The cam 1 can be attached to the rotating shaft 52 such as a cam shaft of an engine 53 (see Figure 1). Seals (not shown) can be provided between the pistons and inner walls of the bores of the hydraulic device 40, as is known in the art.

[0036] The push rod 6 couples motion 51 of the driven piston 46 with the operation of an engine component 11 (e.g. valve, in the case where the hydraulic device 40 is utilized as a timing component for inlet/outlet valve 11 opening/closing of a combustion engine - see Figure 1 or for a fuel injector valve 32 for opening or closing fuel injector port 33 - see Figure 7). Also included is the stop 70 defining for limiting travel of the driven piston 46 within the bore 44a towards the piston 2, recognizing that the bore head 45 can define the limit of travel for the driven piston 46 along the bore 44a axis (one portion of an L-shaped bore by example) opposite the stop 70. Also included can be the air breather port 23 between ambient and the respective piston(s). It is recognized that different axial positions of the floating piston 4 along the bore 44b can be realized for different initial pressures of the hydraulic fluid in the first chamber portion 3b as controlled by the hydraulic circuit 29 (further described below). It is recognized that the greater the initial pressure of the hydraulic fluid in the first chamber portion 3b (e.g. as communicated from the first chamber portion 3a via the passageway 100), the closer the floating piston 4 is positioned towards the respective bore head 45 when the drive piston 2 is at its BDC (Bottom Dead Center).

[0037] It is recognized that travel 49 of the floating piston 4 will occur if the hydraulic fluid pressure in the first chamber portion 3b is greater than the opposing pressure/force delivered to the floating piston 4 by the resilient element 102. It is recognized that travel 49 of the floating piston 4 will not begin if the hydraulic fluid pressure in the first chamber portion 3b is less than the opposing pressure/force delivered to the floating piston 4 by the resilient element 102. It is recognized that travel 49 of the floating piston 4 will stop if the hydraulic fluid pressure in the first chamber portion 3b matches the opposing pressure/force delivered to the floating piston 4 by the resilient element 102. As such, it is recognized that travel 49 of the floating piston 4 towards the bore head 45 is expended (e.g. stops) when the pressure of the hydraulic fluid in the first chamber portion 3b is balanced by the force applied to the floating piston 4 by a resilient element 102 (e.g. mechanical spring, volume of compressible fluid, etc.) located in the second chamber 5. For example, the resilient element 102 can be a specified volume of compressible fluid deposited within the second chamber 5, such that travel of the floating piston 4 towards bore end 45 compresses the resilient element 102 (e.g. gas) until the pressure of the hydraulic fluid in the first chamber portion 3b matches the pressure of the resilient element 102 (i.e. gas) in the second chamber 5. Alternatively, the resilient element 102 can be the mechanical spring, such that forces exerted by the resilient element 102 match the opposite force acting against the floating piston 4 due to pressure of the hydraulic fluid in the first chamber portion 3a.

[0038] As such, travel 48 performed by the drive piston 2 towards the floating piston 4 (away from BDC), in order to cause compression of the resilient element 102 by resulting travel 49 of the floating piston 4, is less for an initial higher pressure (i.e. set amount 101 - see Figure 9) of the hydraulic fluid in the first chamber portions 3a, b than for initial lower pressures of the hydraulic fluid in the first chamber portions 3a, b, recognizing that compression of the low pressure fluid in the first chamber portions 3a,b by travel 48 of the drive piston 2 increases the compression of the resilient element 102 in the second chamber 5. Once the travel 49 of the floating piston 4 is expended towards the bore head 45 (i.e. the fluid pressure in the first chamber portion 3b achieves matching of the opposite force applied to the floating piston 4 by the compressed resilient element 102), further increase in pressure in the first chamber portion 3a (by continued travel 48 of the drive piston 2) causes travel 51 of the driven piston 46 to compress the resilient element 104. [0039] For example, the resilient element 104 can be a specified volume of compressible fluid deposited within the third chamber 7, such that pressure of the hydraulic fluid in the first chamber portion 3a compresses the resilient element 104 (e.g. gas) until the pressure of the hydraulic fluid in the first chamber portion 3a matches the pressure of the resilient element 104 (i.e. gas) in the third chamber 7. Alternatively, the resilient element 104 can be a mechanical spring, such that forces exerted by the resilient element 104 match the force acting against the driven piston 46 due to pressure of the hydraulic fluid in the first chamber portion 3a. Once the pressure in the chamber 3a, is greater than the opposing pressure/force applied by the resilient element 104 to the driven piston 46, any further travel 48 of the drive piston 2 will result in simultaneous travel 51 of the driven piston 46 with the drive piston 2.

[0040] In terms of fluid isolation of first chamber portion 3a from first chamber portion 3b, via closing of passageway 100, further described below is operation of one embodiment of an optional valve 106 in bore 108, with respect to a resilient element 109 (e.g. set volume of compressible fluid, spring, etc.). As such, valve 106 is responsible for interrupting or allowing fluid continuity of the passageway 100 between the first chamber portions 3a,b.

[0041] It is recognized that driven piston 46 can remain stationary against stop 70 for as long as the pressures forces in chambers 3a, 7 equalize, which can occur due to travel of the drive piston 2 once the set pressure force of the resilient element 102 in the second chamber 5 is equalized with the hydraulic fluid pressure in the first chamber portion 3a. As further discussed below, once the pressures in the chambers 3a, b, 5, 7 are equalized, due to travel of the drive piston 2 away from BDC, further travel of the drive piston 2 away from BDC will cause movement 51 of the piston 46 simultaneously towards the bore head 45, which will cause movement/operation of the engine component 11 coupled to the push rod 6 (e.g. a rise in pressures in the chamber 3a higher than the initial set pressure/force of the resilient element 104 in the third chamber 7. Optional operation of the valve 106 prior to travel 51 of the driven piston 46 is further described below. [0042] The push rod 6 can be used to couple the hydraulic device 40 to the engine component 11 (e.g. see Figures 1 ,6 as the valve 11 via valve stem 10, whereby the valve 11 is configured for seating within the valve seat 54 of cylinder head 27 of the engine 53). Alternatively as shown in Figure 7, push rod 6 can be used to couple the hydraulic device 40 to the engine component 11 as a fuel injector valve 32 for opening or closing fuel injector port 33 in fluid communication with the injection port 64 and cylinder 58 shown in Figure 1. This can provide the case where the hydraulic device 40 is utilized as a timing component for an injector valve 32 opening/closing for the combustion engine 53.

[0043] Referring again to Figure 8, one embodiment of the hydraulic circuit 29 used to provide hydraulic fluid to the first chamber portions 3a,b includes a supply piston 110 driven by servo motor 112 for inducing travel 114 of the piston 110 in a bore 116. Valve 118 (e.g. check valve) facilitates egress of hydraulic fluid out of bore 16 (as driven by travel 114 of the piston 110 towards the valve 118) and into intermediate chamber 120 (e.g. via a further valve 118). Hydraulic fluid entering intermediate chamber 120 is introduced into the first chamber portion 3a via fluid passageway 124. Pressure sensor 126 (e.g. pressure transducer) can sense pressure of the hydraulic fluid in the first chamber portion 3a via fluid passageway 128. Further, valve 130 (e.g. electronically controlled) can be used to control how/if the supply piston 110 provides hydraulic fluid to a plurality of other piston 2,4,46 combinations associated with other engine components 1 (not shown), for example one piston 2,4,46 combination per engine cylinder as desired. Accordingly, the supply piston 1 0 can supply hydraulic fluid from the bore 116 through gallery 128 simultaneously to a plurality of first chamber portions 3a, b i.e. one first chamber portions 3a,b per engine cylinder. As further described below, an optional common header 150 can be used to facilitate the supply from the common header to a plurality of chambers 120 (e.g. four chambers 120, one for each cylinder of a four cylinder engine). Accordingly, each of the chambers 120 would feed hydraulic fluid to each cylinder associated arrangement of chambers 3a, 3b with respective pistons 2,4,46,106 and cam 1. For example for a 4 cylinder engine the system 4 would have the common header 150 feeding four chambers 120 (one assigned to each cylinder) that in turn feed four arrangements of passageways 100,124, chambers 3a,3b, and pistons 2,4,46,106 (one set assigned to each cylinder). Also considered is that there would be four sets of resilient elements 102,104,109 (one set per cylinder).

[0044] The hydraulic circuit 29 is supplied with hydraulic fluid via a top up piston 130 positioned in bore 132 with corresponding actuator 134 (e.g. electronically controller servo motor) and valving (e.g. check valves) 118. The bore 132 is supplied hydraulic fluid via supply line 136 via operated valve 138 from a fluid pumping source associated with fluid reservoir 140. As further described below, the top up piston 130 is operated by the actuator 134 to provide additional hydraulic fluid to the intermediate chamber 120 (e.g. via common chamber 150) when fluid pressure drop is sensed by the pressure sensor 126 after the intermediate chamber 120 is supplied with a measured set amount 101 of hydraulic fluid (i.e. to effect initial positioning of the floating piston 4 within the first chamber portion 3b to represent a desired amount of lag for operation of the engine component 11). It is recognized that losses of hydraulic fluid deposited into the intermediate chamber 120 can be experienced in operation (e.g. travel 48,49,51) of the pistons 2,4,46, due to leakage past seals (e.g. piston rings - not shown) between the sidewalls of the pistons 2,4,46 and the respective sidewalls of the chambers 3a,b,5,7.

[0045] In one exemplary embodiment, the resilient elements 102,104,109 can be mechanical springs used to resist travel 49,51 of the respective pistons 4,46 towards the bore ends 45, in response to hydraulic fluid pressure in the intermediate chamber 102 and the first chamber portions 3a, b. In other words, hydraulic fluid pressure in the chambers 120, 3a, 3b, as moderated by travel 48 of the drive piston 2 under influence of the cam 1 , is used to force travel 49,51 of the respective pistons 4,46 towards the bore ends 45 and compress the resilient elements 102,104,109 when the hydraulic fluid is of sufficient pressure to exert a greater force (than that of the resilient element 102,104,109) against the piston 4,46 face that is opposite the piston face acted upon by the resilient element 102,104,109. As further described below, each of the resilient elements 102,104,109 can be of a different strength (e.g. spring force when a mechanical spring, initial pressure when a compressible fluid, etc.). For example, the resilient element 102 is of a strength less than that of resilient element 104. In the case where valve 106 is operated based on the presence of resilient element 109 (e.g. another option is where valve 106 is electronically controlled), resilient element 102 strength would be less than resilient element 109 strength which would be less than resilient element 104 strength, such that increasing hydraulic fluid pressure in the chambers 3a, b, 120 (due to travel 48 of the piston 2) would initiate travel 49 (i.e. overcome resistance of the resilient element 102) of the floating piston 4 towards the bore end 45, then travel of the valve 106 (i.e. overcomes resistance of the resilient element 109) towards the respective bore end 45 to close off fluid communication between the chambers 3a, b via passageway 100, and then initiate travel 51 (i.e. overcomes resistance of the resilient element 104) of the driven piston 46 towards the bore end 45 (i.e. thus operating engine component 11 such as a combustion chamber inlet/outlet valve or fuel injector valve).

[0046] Referring again to Figure 8, the hydraulic device 40 can have the resilient elements 102,104,109 placed (e.g. a measure volume of compressible fluid or a mechanical spring) in the respective chamber 5,7 108. The intermediate chamber 120 is supplied via hydraulic circuit 29 with set amount 101 (see Figure 9) of incompressible (e.g. hydraulic oil) fluid from bore 116 via supply piston 110 in order to affect the initial position of the floating piston 4 in the first chamber portion 3b. It is recognized that position of the floating piston 4 in the first chamber portion 3b can be at a number of positions with respect to the bore end 45.

[0047] For example, if the set amount 101 is of sufficient pressure to completely compress the resilient element 102, then the floating piston 4 will be positioned adjacent to the respective bore end 45 and therefore any further increase in the pressure of the hydraulic fluid (i.e. via travel 48 of the drive piston 2) will not further move the floating piston 4 towards the bore end 45 (i.e. the set amount 101 pre-compresses the resilient element 102 to its maximum compression amount/position). In this example the set amount 101 can represent a "no lag" example, such that any travel 48 of the drive piston 2 (after the set amount 101 is deposited into the chambers 3a, b, 120) will induce travel 51 of the driven piston 46. In the case where the valve 106 is utilized (i.e. optional), once the pressure of fluid in 3b forces travel 49 of the floating piston 4 to its furthest extent towards the bore end 45, additional increase in fluid pressure in chamber 3a will cause travel of the valve 106 towards its bore end 45 against the resilient element 109, thus closing off passageway 100 and thereby isolating the travel 51 of driven piston 46 from travel 49 (and any oscillations therein) of the floating piston 4.

[0048] In an alternative example, if the set amount 101 is less than the sufficient pressure needed to completely compress the resilient element 102, then the floating piston 4 will be positioned at a respective axial position spaced apart from the respective bore end 45 (i.e. not adjacent thereto) and therefore any further increase in the pressure of the hydraulic fluid (i.e. via travel 48 of the drive piston 2) will further move the floating piston 4 towards the bore end 45 (i.e. the set amount 101 pre- compresses the resilient element 102 to less than its maximum compression amount/position). In this example the set amount 101 can represent a "lag" example, such that any travel 48 of the drive piston 2 (after the set amount 101 is deposited into the chambers 3a,b,120) will induce travel 49 floating piston 4 before inducing travel 51 of the driven piston 46. Similarly, in the case where the valve 106 is utilized (i.e. optional), once the pressure of fluid in 3b forces travel 49 of the floating piston 4 to its furthest extent towards the bore end 45, additional increase in fluid pressure in chamber 3a will cause travel of the valve 106 towards its bore end 45 against the resilient element 109, thus closing off passageway 100 and thereby isolating the travel 51 of driven piston 46 from travel 49 (and any oscillations therein) of the floating piston 4.

[0049] Accordingly, in the event that the optional valve 106 is included in the hydraulic device 40, it can be designed such that once the resilient element 102 is compressed, further increases in the pressure of the hydraulic fluid in the chambers 3a,b,120 would overcome the strength of the resilient element 109 and thus move the valve 106 towards the respective bore end 45 to close passageway 100 and thus inhibit further communication of hydraulic fluid between the chamber 3a and chamber 3b. The closing of the passageway 100 can be advantageous in the event of pressure oscillations in the hydraulic fluid in chamber 3b are induced due to the compression of the resilient element 102, as when the passageway 100 is open any pressure oscillations can travel from the chamber 3b to the chamber 3a via the passageway 100. It is recognized that pressure oscillation present in the hydraulic fluid in chamber 3a could affect travel 51 of the driven piston 46 (e.g. induce similar oscillation) and thus propagate those oscillations to operation of the engine component 11 (e.g. undesirably oscillate opening and closing of a valve coupled to push rod 6).

[0050] As recognized, once hydraulic fluid pressure in the chamber 120 decreases, i.e. due to travel of the drive piston 2 back towards BDC, the resilient elements 102,104,109 will effect travel of their respective pistons/valves 4,46,106 away from the respective bore ends 45 and back to their bore position as defined by the set amount 101 of the hydraulic fluid as originally delivered by the supply piston 110. As discussed above, any further drop in hydraulic fluid pressure in the chamber 120 as sensed by the pressure sensor 126 will cause operation of the actuator 134 in order to drive the top up piston 130 to supply additional or top up hydraulic fluid from the bore 132 to the intermediate chamber 120, thus facilitating maintaining the set amount 101 of hydraulic fluid in the chambers 3a,b,120 (e.g. when the drive piston is at BDC as shown in Figure 8).

[0051] Referring to Figures 8,9,10,11 , in operation of the hydraulic device 40, first hydraulic fluid is injected into the first chamber portions 3a, b via intermediate chamber 120 (using the hydraulic circuit 29) to a selected pressure (e.g. 40 psi), recognizing that in Figure 9 the injection pressure is such that the floating piston 4 is positioned spaced apart from the bore end 45 (i.e. the resilient element 102 is only partially compressed - meaning less than its maximum compression) due to injection of the set amount 101 by the supply piston 110 into the chambers 3a, b, 120. Also noting that valve 106 remains open thus facilitating flow of hydraulic fluid from chamber 3a to chamber 3b via open passageway 100.

[0052] Referring to Figure 10, reciprocation 48 of drive piston 2 (under influence of cam 1 and resulting motion of pushrod 50) from BDC towards the cylinder head 45 will cause travel of the drive piston 2 to decrease the volume of the first chamber 3a (i.e. decrease L- shaped axial bore distance between pistons 2,46) until pressure of the compressible fluid in the chamber 3b balances that of the resilient element 102 set in the second chamber 5 (e.g. 190 psi), thus compressing the resilient element 102 completely and thus placing the floating piston 4 at its maximum travel in the bore 44b (e.g. adjacent to the bore end 45). [0053] Once the floating piston 4 is at maximum travel, referring to Figure 11 , further travel 48 of the piston 2 away from BDC will cause the hydraulic fluid pressure to rise in the intermediate chamber 120 and thus move the valve 106 against the resilient element 109 (resulting in its compression) to close the passageway 100. As well, once the passageway 100 is closed, travel 48 of the drive piston 2 causes travel 51 of the driven piston 46 away from its respective TDC towards its BDC (representing maximum open/operation of the engine component 11. Accordingly, it is recognized that as per the above described operation of the other embodiments of the hydraulic device 40, any movement of the driven piston 46 away from stop 70 will cause opening/operation of the engine component 11 (e.g. valve 1 1 from the closed position to the open position). It is recognized that timing of the engine component 11 operation is delayed until travel of the drive piston 2 causes force on either side of the floating piston to equalize (hydraulic fluid pressure in chamber 3b matches the compressive strength of the resilient element 102).

[0054] Referring to Figure 12, travel 48 of the drive piston 2 has occurred from its TDC to its BDC, thus causing the pressure of hydraulic fluid in the chamber 3a to be less than the forces of the resilient elements 102,104,109, thus providing for a return of the driven piston 46 to its TDC (reversing the previous operation of the engine component 11 such as to close a valve), a return of the floating piston 4 to its position according to the set amount 101 (of hydraulic fluid) after the return of the valve 106 to its open position (i.e. the passageway 100 facilitates fluid communication between chambers 3a,b). It is recognized that a decrease in pressure of the fluid in chamber 3a is reflected in the fluid pressure in chamber 120, such that when the pressure is less than the opposing force of the resilient element 09, the valve 106 will reverse from its closed position to its open position. Once the valve 106 is open and the chambers 3a, b are fluidly connected by open passageway 100, any the drop in fluid pressure in chamber 3a will be reflected in chamber 3b and therefore allow for expansion of the resilient element 102 to move/travel 49 the floating piston 4 back towards its initial bore 44b position (as defined by the set amount 101).

[0055] Referring to Figure 13, in the event that pressure of the hydraulic fluid in the intermediate chamber 120 is sensed by the pressure sensor 126 at a pressure less than the initial set amount 101 initially delivered by the hydraulic circuit 29 (i.e. setting the degree of lag timing desired for the engine component 11 - see Figure 9), the top up piston 130 is actuated by actuator 134 (e.g. from BDC) towards the valve 118 in order to expel reserve hydraulic fluid 103 from the bore 132, past valve 118 (optionally into common header 150 in the case of multiple chambers 120) and into the intermediate chamber 120 in order to raise the pressure of the hydraulic fluid back to the preset amount. Once the original pressure of the preset amount 101 is reached, the pressure sensor 126 senses this and the actuation of the top up piston 130 can cease. Accordingly, anytime that the pressure sensor 126 determines that the pressure in the intermediate chamber 120 (and thus the chamber(s) 3a,3b) is less than the set amount 101 , the actuator 134 can be controlled to expel reserve hydraulic fluid 103 from the top up bore 132 without affecting the position of the supply piston 110 (i.e. the position of which representing the predefined setting for the set amount 101). It is also recognized that due to the presence of the vales 118, the system 40 can operate to retract top up piston 130 and/or supply piston 110 away from the valves 118 without affecting the set amount 101 deposited in the system 40.

[0056] Referring to Figure 14, when a controller (not shown) of the hydraulic device 40 detects (e.g. via a position sensor not shown) that the position of the top up piston 130 in the bore 132 indicates the amount of hydraulic fluid in the bore 132 is running out, activation of supply valve 138 (e.g. electronically controlled, pressure controlled, etc.) can cause additional hydraulic fluid to be pumped from the oil reservoir 140 and into the bore 132, thus pushing the top up piston 130 back towards BDC. Once returned to BDC, the bore 132 is considered ready to supply more reserve hydraulic fluid 103 (see Figure 13) as determined by the pressure sensor 126.

[0057] Referring to Figure 15, an alternative embodiment of the hydraulic circuit 29 is shown. In this example, the pressure sensor 126 can sense when the pressure in the chambers 3a,b,120 is less than the set amount 101 (see Figure 9), by keeping common chamber 150 supplied with hydraulic fluid at the correct pressure reflected by the defined pressure of the set amount 101. Accordingly, pressure control valve PCV1 (operated when pressure sensor 126 detects a fluid pressure deficiency) can facilitate the supply of hydraulic fluid (from the fluid reservoir 140) into common chamber 150 (for supplying one or more chambers 120) at the fluid pressure of the set amount 101 , hence keeping chamber 150topped up with hydraulic fluid. Valve 118 provides that for any fluid pressures in chamber 120 higher than that of the set amount 101 (e.g. under influence of travel 48 of the drive piston 2), the pressure of chamber 150 will remain at the fluid pressure of the set amount 101 as dictated by pressure sensor 126 and control valve PCV1. Accordingly, once the set amount 101 is deposited from chamber 150 into chamber 120 (and the associated chambers 3a, 3b), any drop in fluid pressure below that of the set amount 101 (e.g. due to fluid loss through piston seals) will result in top up fluid supplied from the chamber 150 (which is kept at the fluid pressure of the set amount 101 via operation of the pressure sensor 126 and control valve PCV1). Further, in the event that a lesser amount of fluid than what is presently in the chambers 120, 3a, 3b (i.e. a different timing via a different set amount 101 is desired), control valve PCV2 can be operated to release, via valve 119, deemed excess hydraulic fluid out of the chamber 120 (and the associated chambers 3a,3b) and back to fluid reservoir 140 via chamber 152. For a different set amount 101 , the pressure sensor 126 and control valve PCV1 will be reset to reflect any newly desired set amount 101.

Referring to Figure 16, shown is an alternative embodiment to the hydraulic device 40 of Figure 8. In particular, the device of Figure 8 has the cam 1 placed adjacent to the housing 42. In Figure 16, the cam 1 is positioned below the housing 42 and there for relies upon a pivot point 160 positioned on the housing 42, which is connected to a pivot arm 162. The pivot arm 162 is positioned adjacent to both the push rod 50 connected to drive piston 2 and a second rod 164 connected to a follower 166 for following the surface of the cam 1. As such, as the cam 1 rotates, rod 164 pushes on pivot arm 162 which then pivots about pivot point 160 and thus pushes pushrod 50. It is recognized that there could be a return spring (not shown) used to maintain contact between the pushrod 50 and the pivot arm 162, as desired. Figure 17 shows an alternative embodiment of the hydraulic device 40, such that the cam 1 is positioned above the housing 42. It is recognized that the position of the cam 1 with respect to the housing 42 will depend upon spatial considerations of the engine 53 pertaining to the spatial relationship between the engine cylinder 56 (see Figure 1) and the housing 42.