US20040020453A1

US20040020453A1 - Damped valve controller

Info

Publication number: US20040020453A1
Application number: US10/452,752
Authority: US
Inventors: James Yager; Ning Lei
Original assignee: Individual
Current assignee: Individual
Priority date: 2002-02-05
Filing date: 2003-06-02
Publication date: 2004-02-05

Abstract

A damping assembly for an engine valve, the engine valve being an intake/exhaust valve, the engine valve admitting/exhausting a fluid mixture into/from a combustion chamber of an internal combustion engine includes damping apparatus having a damping chamber being selectively in fluid communication with a source of pressurized actuating fluid and being in fluid communication with a substantially ambient actuating fluid reservoir and being operably coupled to the engine valve. The chamber is floodable with a volume of actuating fluid, venting of actuating fluid from the chamber being selectively restricted. The restriction imparts a force to the engine valve acting to moderate engine valve landing speed during a closing stroke of the engine valve. A method of control is further included.

Description

RELATED APPLICATIONS

The present application is a continuation-in-part of U.S. patent application Ser. No. 10/072,490, filed Feb. 5, 2002, and a continuation-in-part of U.S. patent application Ser. No. 10/105,482, filed Mar. 25, 2002, both being incorporated herein by reference.[0001]

TECHNICAL FIELD

The present application relates to internal combustion engine valve control. More particularly, the present application relates to camless control of engine intake/exhaust valves.

BACKGROUND AND PRIOR ART

There is a need in the industry for increased control of internal combustion operating parameters in order to provide for efficient and powerful operation, while at the same time, minimizing the emissions of noxious byproducts of combustion and minimizing noise emissions. The issue of noise emissions is particularly a problem with combustion ignition engines, and most particularly, a problem at idle speed conditions and during cold start-up. A source of the noise emissions is the landing impact of engine air (intake/exhaust) valves. A harsh landing impact also adversely affects the durability of valve train components.

SUMMARY OF THE INVENTION

The present invention substantially meets the needs of the industry. Control of the engine valve landing speed is achieved by a damping device that modulates the velocity of the engine valve as the engine valve approaches the closed condition, in one embodiment and modulates landing both in the valve closing and opening conditions in another embodiment.

The present invention is a damping assembly for an engine valve, the engine valve being an intake/exhaust valve, the engine valve admitting/exhausting a fluid mixture into/from a combustion chamber of an internal combustion engine includes damping apparatus having a damping chamber being selectively in fluid communication with a source of pressurized actuating fluid and being in fluid communication with a substantially ambient actuating fluid reservoir and being operably coupled to the engine valve. The chamber is floodable with a volume of actuating fluid, venting of actuating fluid from the chamber being selectively restricted. The restriction imparts a force to the engine valve acting to moderate engine valve landing speed during a closing stroke of the engine valve. The present invention is further a method of control.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of a valve actuation device of the invention of the parent application; [0006]
FIG. 2 is a sectional view of the valve actuation device of FIG. 1 integrated with the dual control valve of the parent invention; and [0007]
FIG. 3 is a graphic representation of the control strategy for the valve actuation device of FIGS. 1 and 2; [0008]
FIG. 4 is a partially sectioned schematic representation of the closing damping assembly of the present invention integrated with the dual control valve of the parent invention; [0009]
FIG. 5 is an enlarged sectioned schematic representation of the damping assembly of the present invention; [0010]
FIG. 6 is a sectioned schematic representation of the damping assembly of the present invention having frames A-D depicting sequential operating conditions; [0011]
FIG. 7 is a partially sectioned schematic representation of the opening damping assembly of the present invention, having frames A-C depicting sequential operating conditions; [0012]
FIG. 8 is a partially sectioned schematic representation of a further embodiment of the opening damping assembly of the present invention, having frames A-C depicting sequential operating conditions; and [0013]
FIG. 9 is a graphic representation of the control strategy for the damping assembly of FIGS. [0014] 4-8.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a [0015] dual control valve 500 in application on a camless engine. More detail of the structure and operation of an exemplary dual control valve 500 may be had with reference to the parent application. FIG. 2 illustrates the structure of valve actuator 600 in greatest detail. FIG. 3 illustrates the relationship between the control valve 500 and the valve actuator 600.
The [0016] valve actuator 600 contains major components of boost piston 620, drive piston 622 and return piston 618. Pressure in the boost piston control chamber 626 is controlled by the half spool valve (CV1 of FIGS. 4-8) 504. When the half spool control valve 504 is turned on (see FIG. 3), the boost piston chamber 626 of the boost piston 620 is connected to the rail pressure from rail 542, the actuating fluid passing through the half spool valve 504 and passage 624 to the boost piston chamber 626. The boost surface 628 of the boost piston 620 has a relatively large area and it provides sufficient downward force on the engine valve 604 to overcome the incylinder combustion pressure acting in opposition on the valve face 605. The boost piston 620 has of relatively limited stroke 627. Preferably, the stroke 627 is on the order of about 2 mm.
It is desirable that the [0017] stroke 627 of the boost piston 620 be less than the cylinder head to combustion piston clearance at TDC to avoid inadvertent collision of valve 604 and the combustion piston. The stroke limit 627 is realized by a hard stop 629 to the boost piston 620 travel. Due to its limited stroke 627, boost piston 620 can be opened at any time without regard to combustion piston disposition relative to the cylinder head without hitting the combustion piston. The responsibility of the boost piston 620 is to crack open the engine valve 604 at a relatively high in-cylinder pressure condition and hold the valve 604 at the stroke limiter on the stop 629 for a selected period of time. This feature is referred to as engine valve overlapping noted on FIG. 3 as valve overlap.
The [0018] drive piston 622 positioning control pressure charge is controlled by the balance spool valve 502 (CV2 of FIGS. 4-8). Balance spool valve 502 selectively ports high pressure actuating fluid from rail 542 to the drive piston 622 via passage 625 or vents actuating fluid therefrom via vents 537. The drive piston 622 and boost piston 620 are in mechanical contact (the distal end 631 of the boost shank 630 bearing on the drive area 638 of the drive piston 622) when the engine valve 604 opening is less than or equal to the boost stroke limit 627.
When [0019] engine valve 604 travel is greater than the boost limit (the stroke 627), the drive piston 622 and boost piston 620 are mechanically separated (the distal end 631 of the boost shank 630 is no longer bearing on the drive area 638 of the drive piston 622) and the drive piston 622 is responsible for fully opening (see full open position of FIG. 3) the engine valve 604 without the assistance of the boost piston 620. The drive piston 622 and return piston 618 are always in mechanical contact with the engine valve 604 and the contact area beneath the retainer 608 is vented to ambient pressure by the vent 642.
The [0020] drive piston 622 is responsible for fully opening the engine valve 604 by overcoming all biased forces, including the force exerted by the return spring 610, the force exerted by the return piston 618, and any in-cylinder forces acting on the surface of valve 604. The drive piston 622 has the capability to push the valve 604 to the full valve (open) lift position and stay at that position for the entire duration of valve 604 opening. This is effected by appropriately sizing the drive area 638 to generate adequate force by the pressure to be exerted thereon by the actuating fluid ported from CV2 502. The drive piston 622 may be used sequentially or in conjunction with the boost piston 620 during the valve 604 actuation as desired to meet the valve 604 opening needs since the pistons 620, 622 are independently controlled by CV1 502, CV2 604, respectively. The drive piston 622 is capable of traveling the full valve lift distance of valve 604 for any given actuation pressure (pressure in the rail 542) and stops when full travel is reached. How fast drive piston 622 moves is largely a function of the actuation pressure in the rail 542.
The [0021] return piston 618 is operably coupled to the valve spring retainer (valve plate) 608 at the upper margin of the return piston 618. The opposed lower margin 619 forms a portion of the return piston control chamber 640. Chamber 640 is always exposed to actuating fluid pressure from rail 542 during engine operation. The return piston 618 is always connected to the rail pressure in the rail 542 without any control being exerted on the actuating fluid affecting the return piston 618 and accordingly always exerts a closing force on valve 604. The return piston 618 always tends to the push the valve 604 to the closed position in cooperation with the bias exerted by the return spring 610. The drive area 638 of the drive piston 622 is significantly greater than the actuation area 619 of the return piston 618, hence the drive piston 622 can always open the valve 604 against the force exerted by the return piston 618 acting in cooperation with the bias exerted by the return spring 610.
FIG. 3 illustrates the control strategy of the stepped valve motion method. Before the combustion piston reaches the top dead center, TDC, position, the half spool valve (CV[0022] 1) 504 is turned on, porting actuating fluid to the drive the boost piston 620 to its stroke limit 627 position on the stop 629. Since the drive piston 620 is in mechanical contact with the boost piston 622 at the home (initial) position, the entire moving mass (boost piston 620, drive piston 622 and the valve 604) is being pushed the distance of the stroke 627, about 2 mm, to the stop 629 and stopped at that position (see position A of FIG. 3).
The combustion piston continues its approach to TDC and passes TDC without hitting the cracked [0023] open engine valve 604. As soon as the piston passes TDC, the balanced spool valve (CV2) 502 is turned on to trigger the drive piston 622 take off. Rail pressure is now in communication with the drive piston chamber 636 and acting on the drive area 638. The drive piston 622 mechanically separates from the boost piston 620 and pushes the engine valve 604 to the full open extent of its travel (see position B of FIG. 3) by overcoming the biased return piston 618, the return spring 610 preload force and some in-cylinder pressure force acting on valve face 605. The engine valve 604 reaches its fuel travel and stops.
After the desired engine valve opening duration, the balanced spool valve (CV[0024] 2) 502 is turned off and the drive piston chamber 636 is vented through vents 537. The return piston 618 and the return spring 610 then push the engine valve 604 and the drive piston 622 back to the 2 mm position (see position C of FIG. 3). Two different situations can happen at this returning position C.
In the first situation, the [0025] boost piston 620 is still in connection with the rail pressure through the closed control valve (CV1) 504 and the boost piston 620 is still set at its stop 629 at the stroke limit 627. The return piston 618 will carry the engine valve 604 and drive piston 622 together to hit this distal end 631 of the boost piston 620 and will stop against the boost piston 620 due to significant force acting on the boost piston 620 by the actuating fluid in the boost piston chamber 626 acting on the boost surface 628. The engine valve 604 moving mass now is stopped at the 2 mm lift. After a selected period of time, the half spool control valve 504 is shifted to the on position and vents the boost piston chamber 626 through the vent 539. The return piston 618 then pushes the entire mass back to the home position with very small landing velocity (see position D of FIG. 8). The very limited travel distance of the stroke 627 prevents developing high landing velocity before the mass is stopped. This method is very beneficial under high return speed when the engine is operating at relatively high RPM to minimize the valve 604 returning impact.
The second situation is as noted below. The [0026] boost piston chamber 626 is vented before the engine valve 604 returns to the 2 mm position. This occurs by the half spool control valve (CV1) 504 being shifted to the vent position and venting the boost piston chamber 626 through the vent 539. The returning drive piston 622 will then hit the distal end 631 of the boost piston. The entire moving mass is then increased by having to carry the boost piston 620, as well as the drive piston 622 and the valve 604 and this results in an increased system inertia. The entire moving mass accordingly slows down. The reduced return velocity acts to advantageously reduce the impact of the valve 604 on the cylinder head seat 612. This situation is advantageously used in low engine speed conditions and other low rail pressure conditions when the returning speed is relatively low.
The [0027] dual control valve 500 of the present invention having two control valves 502, 504 assures the safety of the valving mechanism 600. The combustion piston to the engine valve 604 collision condition is avoided and return forces of the valve 604 are better controlled.
Enhanced control of the return forces of the [0028] valve 604 is achieved with the return damping assembly of the present invention, depicted generally at 700 in FIGS. 4-6. The return damping assembly 700 of the present invention is depicted in FIGS. 4-6, with the structure of the return damping assembly 700 being depicted primarily in FIGS. 4 and 5 and operation of the return damping assembly 700 being depicted in FIG. 6 in sequential frames A-D. Incorporation of the return damping assembly 700 includes some modifications to the structure of the boost piston 620 and drive piston 622 as described above with reference to FIGS. 1-3.
The [0029] boost piston 620 has an axial bore 702 defined therein. The upper margin of the axial bore 702 is sealed by a plug 704 that is threaded into the boost piston 620. The axial bore 702 defines in part a damping ball chamber 706 and a depending drive piston cylinder 708. The diameter of the damping ball chamber 706 is greater than that of the drive piston cylinder 708.
The damping ball chamber [0030] 706 is intersected by a chamber cross drilling 710. Likewise, the drive piston cylinder 708 is intersected by a piston cross drilling 712. Both the chamber cross drilling 710 and the piston cross drilling 712 are in fluid communication with an annulus 714. The annulus 714 is in fluid communication with CV2 502 via passageway 625. As will be seen, pressure in the annulus 714 is controlled by CV2 502.
The damping ball chamber [0031] 706 is defined by a ball stop 716, comprising the lower margin of the plug 704, in cooperation with a cylinder wall 718 and a step comprising a ball seat 720 that is radially disposed with respect to the drive piston cylinder 708.
The [0032] drive piston 622 utilized with the return damping assembly 700 comprises a cylindrical piston body 722. The piston body 722 has a lower margin 724 that bears on the upper margin of the return spring retainer 608 of the valve 604. The piston body 722 has a ring shaped, planar upper margin 726. A lead piece 728 having a lesser diameter than the piston body 722 projects upward from the upper margin 726. The lead piece 728 has a lead upper margin 730.
The [0033] return damping assembly 700 includes a damping ball 732 disposed within the damping ball chamber 706. The damping ball 732 has a lesser diameter than the diameter of the cylinder wall 718 of damping ball chamber 706. Accordingly, the damping ball 732 is free to float within the damping ball chamber 706. The distance between the ball stop 716 and the lower margin 740 of the chamber cross drilling 710 is less than the radius of the damping ball 732. A damping ball clearance 734 is defined between the circumference of the damping ball 732 and the cylinder wall 718 of the damping ball chamber 706. The damping ball clearance 734 is generally the area defined between the circumference of the damping ball 732 and the circumference of the cylinder wall 718 of the damping ball chamber 706. Accordingly, the damping ball clearance 734 is always the same even if the damping ball 732 floats and is bearing on the ball stop 716.
Actuating fluid flow past the damping [0034] ball 732 must transit the damping ball clearance 734 under all conditions. As will be noted below, the damping ball clearance 734 is a critical dimension with respect to operation of the return damping assembly 700.
The damping [0035] stroke 736 is defined between the ball seat 720 and the upper margin 738 of the piston cross drilling 712. The damping stroke 736 is adjustable by varying the aforementioned distance during formation operations of the boost piston 620 by disposing the piston cross drilling 712 closer to or more distant from the ball seat 720.
FIG. 6 depicts the operation of the [0036] return damping assembly 700. As noted in FIG. 9, return damping as effected by the return damping assembly 700 occurs on the closing stroke of the valve 604.
Operation of the [0037] return damping assembly 700 will first be described during opening of the valve 604. It should noted that no damping is effected by the return damping assembly 700 during the opening stroke of the valve 604. During the opening stroke of the valve 604, CV2 502 is shifted to the open disposition porting high pressure actuating fluid from the rail 542 through the passageway 625 to the annulus 714. Referring to A of FIG. 6, high pressure actuating fluid flows through the chamber cross drilling 710 and floods the upper portion (the portion above the damping ball 732) of the damping ball chamber 706. The pressure of the actuating fluid generates a downward force on the upper hemisphere of the damping ball 732. This force is transmitted to the lead upper margin 730 and accordingly then to the boost piston 620 and the valve 604, tending to drive the boost piston 720 and valve 604 in a downward, opening stroke. A certain portion of the high pressure actuating fluid transits the damping ball clearance 734 and enters the portion of the damping ball chamber 706 that is beneath the damping ball 732. The pressure of the actuating fluid beneath the damping ball 732 acts on the upper margin 726 of the piston body 722, thereby generating a downward force on the boost piston 620 that is additive to the aforementioned force generated on the upper hemisphere of the damping ball 732. The damping ball 732, boost piston 620, and valve 604 translate downward as indicated in frame B of FIG. 6.
Referring to frame C of FIG. 6, the damping [0038] ball 732 is seated on the ball seat 720. At this point, the piston cross drilling 712 is in fluid communication with the drive piston cylinder 708 and high pressure actuating fluid from annulus 714 bears on the upper margin 726 of the boost piston 720, driving the boost piston 620 and the valve 604 further open as indicated in frame D. No damping is effected by the return damping assembly 700 during the opening stroke of valve 604.
The return damping stroke of the [0039] return damping assembly 700 proceeds in the opposite sequence to that described above with reference to the opening stroke. The sequence is from frame D to A of FIG. 6. To initiate the return stroke, CV2 502 shifts from the open disposition to the venting disposition in which high pressure actuating fluid from rail 542 is sealed off and the components serviced by CV2 502 are vented to ambient via vent 537. Accordingly, the pressure of the actuating fluid in the damping ball chamber 706 and the drive piston cylinder 708 drops quickly to ambient. It should be noted that the volumes defined by the damping ball chamber 706 and the drive piston cylinder 708 are still flooded with actuating fluid, but at ambient pressure.
The [0040] valve 604 commences its return, closing stroke as described above with reference to FIGS. 1-3. The closing stroke proceeds from the depiction from frame D to the depiction of frame C with the actuating fluid in the drive piston cylinder 708 being expelled through CV2 502 to ambient. There is relatively little resistance imposed on boost piston 620 by the venting of the actuating fluid from the drive piston cylinder 708.
In frame C, [0041] lead piece 728 of the boost piston 620 comes into contact with the seated damping ball 732. Damping or modulation of the closing velocity of the valves 604 commences once the lead piece 728 is again in contact with the damping ball 732.
Upwards translation of the entire mass, comprising the [0042] valve 604, boost piston 620, and damping ball 732, is limited by forcing the actuating fluid trapped beneath the damping ball 732 through the damping ball clearance 734 and thence to ambient pressure via the chamber cross drilling 710, annulus 714, and CV2 502. The force necessary to expel the trapped actuating fluid is sufficient to slow the closing velocity of the valve 604. The area of the damping ball clearance 734 directly affects reduction in the landing velocity of the valve 604. If the area of the damping ball clearance 734 is too restrictive, the valve 604 approaches a hydraulic lock condition in which all upward, closing motion is terminated. If the area of the damping ball clearance 734 is too great, the landing velocity of the valve 604 is not adequately diminished and the impact of the valve spring retainer 608 on lower margin of the drive piston 622, as depicted in frame A, is too harsh. This harshness adversely affects the durability of the various components and additionally, contributes significantly to engine noise emissions, especially during idle operation of a compression combustion engine. With proper damping ball clearance 734, landing velocity of the valve 604 is modulated as indicated by the dashed line of FIG. 9 referring to return damping.
FIGS. 7 and 8 depict two different embodiments of an [0043] opening damping assembly 800. In both cases the opening damping assembly 800 includes a return pin 822 that is translatable in two opposed directions. When translating upward, the return pin 822 acts to assist the return or closing stroke of the valve 604. When traveling downward, the last portion of the downward stroke of the return pin 822 acts to dampen the opening motion of the valve 604, as noted below.
With reference to the embodiment of FIG. 7, the [0044] opening damping assembly 800 has three major components: housing 820, the return pin 822, and damping ball 824.
The housing [0045] 820 includes a bore 826 defined therein. The bore 826 is preferably spaced apart from and parallel to the stem 605 of the valve 604. The bore 826 is open at the top margin and is blind at the bottom margin. The bore 826 defines a return pin cylinder 828 and a damping chamber 830. The damping chamber 830 has a greater diameter than the return pin cylinder 828. Cylinder cross drilling 832 intersects the return pin cylinder 828 and is in fluid communication with CV2 502 via the fluid passageway 625. Likewise, a chamber cross drilling 834 is in fluid communication with the damping chamber 830. The chamber cross drilling 834 is in fluid communication with CV2 502 via the fluid passageway 625. The upper margin of the damping chamber 830 is a ring shaped, planar step comprising a ball stop 836.
The [0046] return pin 822 is an elongate pin that functions as a valve closing drive piston that acts in cooperation with the bias of the valve spring 610. The return pin 822 has a head 838. The upper margin 840 of the head 838 is operably coupled to the underside of the spring retainer 608 of the valve 604.
A [0047] shank 842 depends from the head 838 and is translatably disposed in the return pin cylinder 828. A lead piece 844 has a smaller diameter than the diameter of the shank 842 and projects downward from the shank 842. A ring-shaped actuator surface 846 defines the lower margin of the shank 842. The lead piece 844 has a lead lower margin 848.
The damping [0048] ball 824 is captured within the damping chamber 830. The damping ball 824 has a damping ball clearance 850 defined between the damping ball 824 and the wall of the damping chamber 830. The damping ball clearance 850 has all the characteristics noted above with reference to the damping ball clearance 734.
The first function of the [0049] return pin 822 is to assist the valve spring 610 in closing the valve 604. To that end, referring to frame C of FIG. 7, CV2 502 is shifted to the open disposition porting high pressure actuating fluid into both the cylinder cross drilling 832 and the chamber cross drilling 834. Initially, the cylinder cross drilling 832 is sealed off by the shank 842 of the return pin 822. High pressure actuating fluid enters the damping chamber 830 and generates an upward directed force on the lower hemisphere of the damping ball 824. The damping ball 824 bears on the lead lower margin 848 of the lead piece 844 and drives the return pin 822 and the valve 604 upward.
The action of the damping [0050] ball 824 in closing the valve 604 is arrested when the damping ball 824 is seated on the ball stop 836. At this point, the actuator surface 846 has intersected the cylinder cross drilling 832 and the high pressure fluid generates an upward directed force on the actuator surface 846 driving both the return pin 822 and the valve 604 in the upward return direction.
Referring to frame A of FIG. 7, as soon as the lower margin [0051] 848 of the lead piece 844 is also exposed through high pressure actuating fluid, a force is generated on the lead lower margin 848 that is additive to the force being generated on the actuator surface 846 to return the valve 604 to the closed disposition.
The opening stroke of the [0052] valve 604 commences at frame A of FIG. 7. CV2 502 is shifted to the vent disposition, dropping the pressure of the actuating fluid in both the return pin cylinder 828 and the damping chamber 830 to ambient. The downward opening stroke of the valve 604 carries with it the return pin 822. As the return pin 822 descends, actuating fluid is expelled from the return pin cylinder 828 through the cylinder cross drilling 832 with essentially no resistance.
Once the [0053] actuator surface 846 descends past the lower margin of the cylinder cross drilling 832, the cylinder cross drilling 832 is sealed off. Actuating fluid in the damping chamber 830 must be forced around the damping ball 824 in the area defined by the damping ball clearance 850. The restriction generated by the damping ball clearance 850 slows the downward translation of the return pin 822. This in turn slows the downward, opening velocity of the valve 604, thereby gradually reducing the landing speed of the valve 604 as the valve 604 achieves it full open disposition. This gradual reduction in landing speed is noted by the dashed lines depicting opening damping in FIG. 9. The reduced landing speed necessarily takes additional time for the valve 604 to achieve its full open position, thereby generating the gradual approach to the full open disposition.
The second embodiment of the [0054] opening damping assembly 800 is depicted in FIG. 8. In the embodiment of FIG. 8, the return pin 822 is a cylindrical sleeve that is concentric with the valve stem 605 of the valve 604. The upper margin 840 of the return pin (sleeve) 822 bears on the underside of the valve spring retainer 608 of the valve 604.
The damping [0055] chamber 830 is formed at the lower margin of the return pin cylinder 828. The ball stop 836 is formed at the inner margin of the chamber cross drilling 834. The ball stop 836 is formed such that when the damping ball 824 is seated on the ball stop 836, as depicted in frame A and B of FIG. 8, an orifice of selected size exists between the damping ball 824 and through the ball stop 836. Accordingly, when the damping ball 824 is seated on the ball stop 836, the chamber cross drilling 834 is fully sealed off with the exception of the area defined by the orifice 852. The orifice 852 is always open for the transmission of actuating fluid. Actuating fluid is therefore free to escape around the damping ball 824, through the orifice 852 and out the chamber cross drilling 834 when the damping ball 824 is seated on the ball stop 836.
Operation of the embodiment of FIG. 8 is similar to operation of the embodiment of FIG. 7 described above. The return, closing stroke of the [0056] valve 604 is initiated by shifting CV2 502 to the open disposition, thereby porting high pressure actuating fluid to both the cylinder cross drilling 832 and the chamber cross drilling 834. Initially, the cylinder cross drilling 832 is sealed off by the return pin (sleeve) 822. High pressure actuating fluid passes through the chamber cross drilling 834 into the damping chamber 830 essentially without restriction as the damping ball 824 is forced out of the path of the high pressure actuating fluid. The high pressure actuating fluid generates a force on the actuator surface 846 driving the return pin 822 and the valve 604 in the upward, closing direction. As soon as the actuator surface 846 passes the lower margin of the cylinder cross drilling 832, additional high pressure actuating fluid is available to generate the upward closing force on the actuator surface 846.
Damping action of the [0057] opening damping assembly 800 of FIG. 8 occurs on the downward, open stroke of the valve 604. The initial portion of the opening stroke of the valve 604 is unopposed by actuating fluid in either the return pin cylinder 828 or the damping chamber 830. CV2 502 is shifted to the vent disposition, dropping pressure in the return pin cylinder 828 and damping chamber 830 to ambient. The cylinder cross drilling 832 is large enough such that the actuating fluid is forced out of the return pin cylinder 828 essentially without opposition.
Referring to frame B of FIG. 8, as soon as the [0058] actuator surface 846 descends beneath the lower margin of the cylinder cross drilling 832, the cylinder cross drilling 832 is sealed off by the return pin 822. The damping action of the opening damping assembly 800 commences at this point. Actuating fluid trapped in the lower portion of the return pin cylinder 828 and the damping chamber 830 can only be expelled by forcing the actuator fluid around the damping ball 824 and through the orifice 852 defined at the ball stop 836. Increasing pressure in the damping chamber 830 forces the damping ball 824 against the ball stop 836 as depicted in frame B of FIG. 8. The resistance imposed on the return pin 822 by the pressure buildup in the damping chamber 830 results in a slowing of the downward velocity of both the return pin 822 and the valve 604, resulting in the reduction in the landing speed of the valve 604 as the valve 604 approaches its full open disposition. This damping is noted in FIG. 9 as the dashed line depicting opening damping.
It will be obvious to those skilled in the art that other embodiments in addition to the ones described herein are indicated to be within the scope and breadth of the present application. Accordingly, the applicant intends to be limited only by the claims appended hereto. [0059]

Claims

What is claimed is:

1. A damping assembly for an engine valve, the engine valve being an intake/exhaust valve, the engine valve admitting/exhausting a fluid mixture into/from a combustion chamber of an internal combustion engine, comprising:

damping apparatus having a damping chamber being selectively in fluid communication with a source of pressurized actuating fluid and being in fluid communication with an actuating fluid vent and being operably coupled to the engine valve, the chamber being floodable with a volume of actuating fluid, venting of actuating fluid from the chamber being selectively restricted, the restriction imparting a force transmittable to the engine valve and acting to moderate engine valve landing speed during a closing stroke of the engine valve.

2. The damping assembly of claim 1 wherein a control valve is operably, fluidly coupled to the chamber for selectively porting actuating fluid to the chamber and venting actuating fluid from the chamber.

3. The damping assembly of claim 1 wherein the chamber is in fluid communication with a drive piston, the drive piston being operably coupled to the engine valve.

4. The damping assembly of claim 3 wherein the control valve is independently operably fluidly couplable to a drive piston drive surface.

5. The damping assembly of claim 1, a damping ball being disposed in the chamber, a damping ball clearance acting to restrict the venting flow of actuating fluid from the chamber.

6. The damping assembly of claim 5 wherein at least a portion of the actuating fluid vented from the chamber transits the damping ball clearance under all operating conditions.

7. The damping assembly of claim 5 wherein the damping ball is free to float in the chamber.

8. The damping assembly of claim 3 wherein actuating fluid ported into the chamber generates a force on a damping ball hemisphere that is transmittable to the drive piston tending to translate the drive piston in an opening stroke.

9. The damping assembly of claim 1 wherein the engine valve has a known full closing stroke, the damping apparatus acting to moderate engine valve landing speed proximate the end of the closing stroke.

10. The damping assembly of claim 4 wherein drive piston translation acts to effect independent fluid coupling of the control valve to the drive surface.

11. The damping assembly of claim 10 wherein venting of actuating fluid from the independent fluid coupling is substantially unrestricted.

12. The damping assembly of claim 10 wherein venting of actuating fluid is restricted to venting form the chamber once the drive piston has sealed off the independent fluid coupling.

13. A damping assembly for an engine valve, the engine valve being an intake/exhaust valve, the engine valve admitting/exhausting a fluid mixture into/from a combustion chamber of an internal combustion engine, comprising:

damping apparatus having a damping chamber being selectively in fluid communication with a source of pressurized actuating fluid and being in fluid communication with an actuating fluid vent and being operably coupled to the engine valve, the chamber being floodable with a volume of actuating fluid, venting of actuating fluid from the chamber being selectively restricted, the restriction imparting a force transmittable to the engine valve and acting to moderate engine valve landing speed during a opening stroke of the engine valve.

14. The damping assembly of claim 13 wherein a control valve is operably, fluidly coupled to the chamber for selectively porting actuating fluid to the chamber and venting actuating fluid from the chamber.

15. The damping assembly of claim 13 wherein the chamber is in fluid communication with a return pin, the return pin being operably coupled to the engine valve.

16. The damping assembly of claim 15 wherein the control valve is independently operably fluidly couplable to a return pin actuating surface.

17. The damping assembly of claim 13, a damping ball being disposed in the chamber, a damping ball clearance acting to restrict the venting flow of actuating fluid from the chamber.

18. The damping assembly of claim 17 wherein at least a portion of the actuating fluid vented from the chamber transits the damping ball clearance under all operating conditions.

19. The damping assembly of claim 17 wherein the damping ball is free to float in the chamber.

20. The damping assembly of claim 16 wherein actuating fluid ported into the chamber generates a force on a damping ball hemisphere that is transmittable to the return pin tending to translate the return pin in a closing stroke.

21. The damping assembly of claim 13 wherein the engine valve has a known full opening stroke, the damping apparatus acting to moderate engine valve landing speed proximate the end of the opening stroke.

22. The damping assembly of claim 17 wherein return pin translation acts to effect independent fluid coupling of the control valve to a return pin actuating surface.

23. The damping assembly of claim 22 wherein venting of actuating fluid from the independent fluid coupling is substantially unrestricted.

24. The damping assembly of claim 22 wherein venting of actuating fluid is restricted to venting from the chamber once the return pin has sealed off the independent fluid coupling.

25. A damping assembly for an engine valve, the engine valve being an intake/exhaust valve, the engine valve admitting/exhausting a fluid mixture into/from a combustion chamber of an internal combustion engine, comprising:

return damping apparatus having a first damping chamber being selectively in fluid communication with a source of pressurized actuating fluid and being in fluid communication with a substantially ambient actuating fluid vent and being operably coupled to the engine valve, the chamber being floodable with a volume of actuating fluid, venting of actuating fluid from the chamber being selectively restricted, the restriction imparting a force transmittable to the engine valve and acting to moderate engine valve landing speed during a closing stroke of the engine valve: and

opening damping apparatus having a second damping chamber being selectively in fluid communication with a source of pressurized actuating fluid and being in fluid communication with a substantially ambient actuating fluid vent and being operably coupled to the engine valve, the second chamber being floodable with a volume of actuating fluid, venting of actuating fluid from the second chamber being selectively restricted, the restriction imparting a force transmittable to the engine valve and acting to moderate engine valve landing speed during a opening stroke of the engine valve.

26. The damping assembly of claim 25 wherein a control valve is operably, fluidly coupled to the first chamber for selectively porting actuating fluid to the first chamber and venting actuating fluid from the first chamber.

27. The damping assembly of claim 25 wherein the first chamber is in fluid communication with a drive piston, the drive piston being operably coupled to the engine valve.

28. The damping assembly of claim 27 wherein the control valve is independently operably fluidly couplable to a drive piston drive surface.

29. The damping assembly of claim 25, a damping ball being disposed in the first chamber, a damping ball clearance acting to restrict the venting flow of actuating fluid from the first chamber.

30. The damping assembly of claim 29 wherein at least a portion of the actuating fluid vented from the first chamber transits the damping ball clearance under all operating conditions.

31. The damping assembly of claim 29 wherein the damping ball is free to float in the first chamber.

32. The damping assembly of claim 27 wherein actuating fluid ported into the first chamber generates a force on a damping ball hemisphere that is transmittable to the drive piston tending to translate the drive piston in an opening stroke.

33. The damping assembly of claim 25 wherein the engine valve has a known full closing stroke, the damping apparatus acting to moderate engine valve landing speed proximate the end of the closing stroke.

34. The damping assembly of claim 28 wherein drive piston translation acts to effect independent fluid coupling of the control valve to the drive surface.

35. The damping assembly of claim 34 wherein venting of actuating fluid from the independent fluid coupling is substantially unrestricted.

36. The damping assembly of claim 34 wherein venting of actuating fluid is restricted to venting form the first chamber once the drive piston has sealed off the independent fluid coupling.

37. The damping assembly of claim 36 wherein a control valve is operably, fluidly coupled to the second chamber for selectively porting actuating fluid to the second chamber and venting actuating fluid from the second chamber.

38. The damping assembly of claim 36 wherein the second chamber is in fluid communication with a return pin, the return pin being operably coupled to the engine valve.

39. The damping assembly of claim 38 wherein the control valve is independently operably fluidly couplable to a return pin actuating surface.

40. The damping assembly of claim 36, a second damping ball being disposed in the second chamber, a second damping ball clearance acting to restrict the venting flow of actuating fluid from the second chamber.

41. The damping assembly of claim 40 wherein at least a portion of the actuating fluid vented from the second chamber transits the second damping ball clearance under all operating conditions.

42. The damping assembly of claim 40 wherein the second damping ball is free to float in the second chamber.

43. The damping assembly of claim 39 wherein actuating fluid ported into the second chamber generates a force on a second damping ball hemisphere that is transmittable to the return pin tending to translate the return pin in an closing stroke.

44. The damping assembly of claim 25 wherein the engine valve has a known full opening stroke, the second damping apparatus acting to moderate engine valve landing speed proximate the end of the opening stroke.

45. The damping assembly of claim 28 wherein return pin translation acts to effect independent fluid coupling of the control valve to a return pin actuating surface.

46. The damping assembly of claim 45 wherein venting of actuating fluid from the independent fluid coupling is substantially unrestricted.

47. The damping assembly of claim 45 wherein venting of actuating fluid is substantially restricted to venting from the second chamber once the return pin has sealed off the independent fluid coupling.

48. A method of control for a valve, comprising:

fluidly coupling a selectively actuatable controller with a source of pressurized actuating fluid and with a substantially ambient actuating fluid reservoir; and

controlling closing landing speed of the valve by:

a. operably coupling a chamber to the valve;

b. selectively independently porting actuating fluid to the chamber; and

c. selectively restricting actuating venting actuating fluid from the chamber, the restricting imparting a force to the valve acting to moderate valve closing landing speed.

49. The method of claim 48 including fluidly communicating the chamber with a drive piston and operably coupling the drive piston to the valve.

50. The method of claim 48 including disposing a ball in the chamber, forming a damping ball clearance between the damping ball and a chamber wall, and restricting the venting flow from the chamber by means of the damping ball clearance.

51. The method of claim 50 including venting at least a portion of the actuating fluid through the damping ball clearance under all operating conditions.

52. The method of claim 50 including generating a force on a damping ball hemisphere by actuating fluid ported into the chamber, transmitting the force to the drive piston, and thereby driving the drive piston in an opening stroke.

53. The method of claim 48, the valve having a known full closing stroke, including moderating valve closing speed proximate the end of the closing stroke.

54. A method of control for a valve, comprising;

controlling closing landing speed of the valve by:

a. operably coupling a chamber to the valve;

b. selectively independently porting actuating fluid to the chamber; and

c. selectively restricting actuating venting actuating fluid from the chamber, the restricting imparting a force to the valve acting to moderate valve opening landing speed.

55. The method of claim 54 including fluidly communicating the chamber with a return pin and operably coupling the return pin to the valve.

56. The method of claim 54 including disposing a ball in the chamber, forming a damping ball clearance between the damping ball and a chamber wall, and restricting the venting flow from the chamber by mean of the damping ball clearance.

57. The method of claim 56 including venting at least a portion of the actuating fluid through the damping ball clearance under all operating conditions.

58. The method of claim 56 including generating a force on a damping ball hemisphere by actuating fluid ported into the chamber, transmitting the force to the return pin, and thereby driving the return pin in an closing stroke.

59. The method of claim 54, the valve having a known full opening stroke, including moderating valve closing speed proximate the end of the opening stroke.

60. A method of control for a valve, comprising:

fluidly coupling a selectively actuatable controller with a source of pressurized actuating fluid and with a substantially ambient actuating fluid reservoir;

controlling closing landing speed of the valve by:

a. operably coupling a chamber to the valve;

b. selectively independently porting actuating fluid to the chamber; and

c. selectively restricting actuating venting actuating fluid from the chamber, the restricting imparting a force to the valve acting to moderate valve closing landing speed; and

controlling opening landing speed of the valve by:

a. operably coupling a second chamber to the valve;

b. selectively independently porting actuating fluid to the second chamber; and

c. selectively restricting actuating venting actuating fluid from the second chamber, the restricting imparting a force to the valve acting to moderate valve opening landing speed.

61. The method of claim 60 including fluidly communicating the chamber with a drive piston and operably coupling the drive piston to the valve.

62. The method of claim 60 including disposing a ball in the chamber, forming a damping ball clearance between the damping ball and a chamber wall, and restricting the venting flow from the chamber by mean of the damping ball clearance.

63. The method of claim 61 including venting at least a portion of the actuating fluid through the damping ball clearance under all operating conditions.

64. The method of claim 62 including generating a force on a damping ball hemisphere by actuating fluid ported into the chamber, transmitting the force to the drive piston, and thereby driving the drive piston in an opening stroke.

65. The method of claim 60, the valve having a known full closing stroke, including moderating valve closing speed proximate the end of the closing stroke.

66. The method of claim 60 including fluidly communicating the second chamber with a return pin and operably coupling the return pin to the valve.

67. The method of claim 60 including disposing a ball in the second chamber, forming a damping ball clearance between the damping ball and a second chamber wall, and restricting the venting flow from the second chamber by mean of the damping ball clearance.

68. The method of claim 67 including venting at least a portion of the actuating fluid through the damping ball clearance under all operating conditions.

69. The method of claim 67 including generating a force on a damping ball hemisphere by actuating fluid ported into the chamber, transmitting the force to the return pin, and thereby driving the return pin in an closing stroke.

70. The method of claim 60, the valve having a known full opening stroke, including moderating valve closing speed proximate the end of the opening stroke.