Valve actuator system capable of operating multiple valves with a single cam

Abstract

A valve actuator system is capable of operating a number of valves with a single cam. The system includes a power shaft, a cam mounted around the power shaft and a gear train to drive the cam when the shaft rotates. Hydraulic actuator assemblies corresponding to the number of valves are radially positioned around the shaft axis for operation by the cam. Hydraulic tubes connect each actuator to a valve follower disposed adjacent to the respective valves. The cam profile pressing each actuator plunger in sequence as the cam rotates causes the hydraulic fluid to flow out of the actuator assembly, through the like-numbered pipe, and into the like-numbered follower assembly, which in turn causes the follower plunger to move the like-numbered valve from an open position or a closed position. This occurs sequentially for each valve.

Claims

1. A valve actuator system capable of operating a number of spring-biased valves of a first type with a single cam, the number of first-type valves being two or more, each first-type valve being assigned a number from an operating sequence and being movable between a closed position and an open position, the valve actuator system comprising: a power shaft rotatably mounted in a frame and defining a shaft axis; a first cam rotatably mounted around the power shaft for coaxial rotation relative to the power shaft about the shaft axis, the first cam having a surface defining a first cam profile extending radially from the shaft axis; a first gear train operatively engaged between the power shaft and the first cam to rotationally drive the first cam relative to the power shaft when the power shaft rotates, the first gear train having a gear ratio R.sub.1 not equal to 1 such that when the power shaft rotates at a first rotational speed S.sub.S, the first cam rotates coaxially about the power shaft at a second rotational speed S.sub.C1=S.sub.S/R.sub.1; two or more first-type actuator assemblies corresponding in number to the number of first-type valves to be operated, each actuator assembly being assigned a respective number from an operating sequence and the actuator assemblies being disposed in a radial arrangement around the first cam in order according to the respective assigned operating sequence numbers, each first-type actuator assembly including an actuator housing defining a bore, an internal cavity holding a total volume of a hydraulic fluid, and an outlet port in fluid communication with the internal cavity, an actuator plunger slidably mounted in the bore of the actuator housing such that movement of the actuator plunger relative to the actuator housing will vary the total volume of the hydraulic fluid within the bore and internal cavity causing the hydraulic fluid to flow into or out of the internal cavity; the first-type actuator assemblies being radially positioned relative to the shaft axis such that the first cam profile sequentially presses and releases each actuator plunger as the cam rotates, and the respective actuator housings of the first-type actuator assemblies being connected to the frame such that the respective outlet ports remain at respective fixed locations and respective fixed orientations relative to the frame; two or more linking tubes corresponding in number to the number of first-type valves to be operated, each linking tube being assigned a respective number from the operating sequence, each respective linking tube being connected at a first end to the outlet port of the like-numbered first-type actuator assembly and having a second end in hydraulic communication with the first end; two or more first-type valve follower assemblies corresponding in number to the number of first-type valves to be operated, each follower assembly being assigned a respective number from the operating sequence, each respective valve follower being disposed adjacent to the like-numbered first-type valve to be moved between a closed position and an open position and each first-type valve follower assembly including a follower housing defining a bore, an internal cavity holding a total volume of the hydraulic fluid, and an inlet port in fluid communication with the internal cavity, the inlet port being in fluid connection with second end of the like-numbered linking tube, a follower plunger slidably mounted in the bore of the follower housing such that varying the total volume of hydraulic fluid within the bore and internal cavity will move the follower plunger against the like-numbered valve, and wherein the cam profile pressing each respective actuator plunger as the cam rotates relative to the power shaft causes the hydraulic fluid to flow out of the actuator assembly, through the like-numbered linking pipe, and into the like-numbered follower assembly, which in turn causes the follower plunger to move the like-numbered first-type valve from a first one of an open position or a closed position to the other of the open position of the closed position; and wherein the cam profile subsequently releasing each respective actuator plunger as the cam rotates relative to the power shaft causes the hydraulic fluid to flow out of the like-numbered follower assembly, through the like-numbered linking pipe, and back into the actuator assembly, which in turn causes the follower plunger to move the like-numbered first-type valve back to its previous position.

2. A valve actuator system in accordance with claim 1, wherein the first gear train is a planetary gear set further comprising: a sun gear fixedly mounted on the power shaft to rotate with the power shaft at a first rotational speed in common with the power shaft; a ring gear mounted in the frame around the power shaft to be coaxial with the shaft axis; a planet gear carrier mounted in the frame to be rotatable about the shaft axis; and a plurality of planet gears rotatably mounted on the planet gear carrier, each planet gear simultaneously rotationally engaging the sun gear and the ring gear; wherein the first cam is fixedly mounted to the planet gear carrier to rotate with the planet gear carrier at a second rotational speed in common with the planet gear carrier; and wherein rotating the power shaft at the first rotational speed rotates the first cam at the second rotational speed, the second rotational speed being less that the first rotational speed, to sequentially actuate the first-type valves in accordance with the operational sequence.

3. A valve actuator system in accordance with claim 2, wherein the ring gear is constrained by the frame to move in an arc around the power shaft, and the system further comprises: a first timing lever extending from the ring gear that can rotate the ring gear about the power shaft axis; wherein fixing the position of the timing lever causes the valve actuator system to operate with constant valve timing for the first-type valves; and wherein moving the timing lever in an arc around the power shaft axis varies the valve timing of the first-type valves without changing the location and orientation of the outlet ports of the actuator housings with respect to the frame.

4. A valve actuator system in accordance with claim 1, wherein the first gear train is a planetary gear set further comprising: a sun gear fixedly mounted on the power shaft to rotate with the power shaft at a first rotational speed in common with the power shaft; a ring gear mounted in the frame around the power shaft to be rotatable about the shaft axis; a planet gear carrier mounted in the frame to be coaxial with the shaft axis; and a plurality of planet gears rotatably mounted on the planet gear carrier, each planet gear simultaneously rotationally engaging the sun gear and the ring gear; wherein the first cam is fixedly mounted to the ring gear to rotate with the ring gear at a second rotational speed in common with the ring gear; and wherein rotating the power shaft at the first rotational speed rotates the first cam at the second rotational speed, the second rotational speed being less that the first rotational speed, to sequentially actuate the first-type valves in accordance with the operational sequence.

5. A valve actuator system in accordance with claim 4, wherein the planet gear carrier is constrained by the frame to move in an arc around the power shaft, and the system further comprises: a first timing lever extending from the planet gear carrier that can rotate the planet gear carrier about the power shaft axis; wherein fixing the position of the timing lever causes the valve actuator system to operate with constant valve timing for the first-type valves; and wherein moving the timing lever in an arc around the power shaft axis varies the valve timing of the first-type valves without changing the location and orientation of the outlet ports of the actuator housings with respect to the frame.

6. A valve actuator system in accordance with claim 1, wherein the first gear train is a linear gear set further comprising: a central gear fixedly mounted on the power shaft to rotate with the power shaft at a first rotational speed in common with the power shaft; an idler gear rotationally mounted on a bearing to rotate about an axis parallel to the shaft axis, the idler gear including a large portion rotationally engaged with the central gear to rotate at a second rotational speed when driven by rotation of the central gear, and a small portion connected to, and rotating with, the large portion at the second rotational speed; a cam gear section rotatably mounted over the power shaft to be rotatable relative to the power shaft about the shaft axis, the cam gear section being rotationally engaged with the small portion of the idler gear to rotate at a third rotational speed when driven by rotation of the small portion; and the first cam being fixedly connected to the cam gear section to rotate with the cam gear section about the shaft axis at the third rotational speed in common with the cam gear section, and wherein rotating the power shaft at the first rotational speed rotates the first cam at the third rotational speed, the third rotational speed being less that the first rotational speed, to sequentially actuate the first-type valves in accordance with the operational sequence.

7. A valve actuator system in accordance with claim 6, wherein the idler gear bearing is mounted to a timing lever that is constrained by the frame to move in an arc around the power shaft axis, and wherein fixing the position of the timing lever causes the valve actuator system to operate with constant valve timing for the first-type valves and moving the timing lever in an arc around the power shaft axis varies the valve timing of the first-type valves without changing the location and orientation of the outlet ports of the actuator housings with respect to the frame.

8. A valve actuator system in accordance with claim 1, further comprising: a second cam rotatably mounted around the power shaft for coaxial rotation relative to the power shaft about the shaft axis, the second cam having a surface defining a second cam profile extending radially from the shaft axis; a second gear train operatively engaged between the power shaft and the second cam to rotationally drive the second cam relative to the power shaft when the power shaft rotates, the second gear train having a gear ratio R.sub.2 not equal to 1 such that when the power shaft rotates at the first rotational speed S.sub.S, the second cam rotates coaxially about the power shaft at a second rotational speed S.sub.C2=S.sub.S/R.sub.2; two or more second-type actuator assemblies corresponding in number to a number of second-type valves to be operated, each actuator assembly being assigned a respective number from the operating sequence and the actuator assemblies being disposed in a radial arrangement around the second cam in order according to the respective assigned operating sequence numbers, the second-type actuator assemblies being radially positioned relative to the shaft axis such that the second cam profile sequentially presses and releases each actuator plunger as the second cam rotates; two or more linking tubes corresponding in number to the number of second-type valves to be operated, each linking tube being assigned a respective number from the operating sequence, each respective linking tube being connected at a first end to the outlet port of the like-numbered second-type actuator assembly and having a second end in hydraulic communication with the first end; two or more second-type valve follower assemblies corresponding in number to the number of second-type valves to be operated, each follower assembly being assigned a respective number from the operating sequence, each respective valve follower being disposed adjacent to the like-numbered second-type valve to be moved between a closed position and an open position; wherein the second cam profile pressing each respective second-type actuator plunger as the second cam rotates relative to the power shaft causes the hydraulic fluid to flow out of the actuator assembly, through the like-numbered linking pipe, and into the like-numbered follower assembly, which in turn causes the follower plunger to move the like-numbered second-type valve from a first one of an open position or a closed position to the other of the open position of the closed position; and wherein the second cam profile subsequently releasing each respective actuator plunger as the second cam rotates relative to the power shaft causes the hydraulic fluid to flow out of the like-numbered follower assembly, through the like-numbered linking pipe, and back into the actuator assembly, which in turn causes the follower plunger to move the like-numbered second-type valve back to its previous position.

9. A valve actuator system for an engine having multiple cylinders, each cylinder having an exhaust valve and an intake valve, the actuator system capable of operating multiple exhaust valves with a single exhaust cam and multiple intake valves with a single intake cam, the cylinders being assigned a number from an operating sequence, the valve actuator system comprising: a power shaft rotatably mounted in a frame and defining a shaft axis; an exhaust cam rotatably mounted around the power shaft for coaxial rotation relative to the power shaft about the shaft axis, the exhaust cam having a surface defining an exhaust cam profile extending radially from the shaft axis; a first gear train operatively engaged between the power shaft and the exhaust cam to rotationally drive the exhaust cam relative to the power shaft when the power shaft rotates, the first gear train having a gear ratio R.sub.1 not equal to 1 such that when the power shaft rotates at a first rotational speed S.sub.S, the exhaust cam rotates coaxially about the power shaft at a second rotational speed S.sub.C=S.sub.S/R.sub.1; a first plurality of hydraulic actuator assemblies corresponding in number to the number of cylinders, each actuator assembly being assigned a respective number from an operating sequence and the actuator assemblies being disposed in a radial arrangement around the exhaust cam in order according to the respective assigned operating sequence numbers; a first plurality of linking tubes corresponding in number to the number of cylinders, each linking tube being assigned a respective number from the operating sequence, each respective linking tube being connected at a first end to the like-numbered exhaust actuator assembly and having a second end in hydraulic communication with the first end; a first plurality of hydraulic valve follower assemblies corresponding in number to the number of cylinders, each follower assembly being assigned a respective number from the operating sequence, each respective valve follower being disposed adjacent to the like-numbered exhaust valve to be moved between a closed position and an open position and each valve follower assembly being in fluid connection with second end of the like-numbered linking tube; an intake cam rotatably mounted around the power shaft for coaxial rotation relative to the power shaft about the shaft axis, the intake cam having a surface defining an intake cam profile extending radially from the shaft axis; a second gear train operatively engaged between the power shaft and the intake cam to rotationally drive the intake cam relative to the power shaft when the power shaft rotates, the second gear train having a gear ratio R.sub.2 not equal to 1 such that when the power shaft rotates at the first rotational speed S.sub.S, the intake cam rotates coaxially about the power shaft at a second rotational speed S.sub.C2=S.sub.S/R.sub.2; a second plurality of hydraulic actuator assemblies corresponding in number to the number of cylinders, each actuator assembly being assigned a respective number from an operating sequence and the actuator assemblies being disposed in a radial arrangement around the intake cam in order according to the respective assigned operating sequence numbers; a second plurality of linking tubes corresponding in number to the number of cylinders, each linking tube being assigned a respective number from the operating sequence, each respective linking tube being connected at a first end to the like-numbered intake actuator assembly and having a second end in hydraulic communication with the first end; a second plurality of hydraulic valve follower assemblies corresponding in number to the number of cylinders, each follower assembly being assigned a respective number from the operating sequence, each respective valve follower being disposed adjacent to the like-numbered exhaust valve to be moved between a closed position and an open position and each valve follower assembly being in fluid connection with second end of the like-numbered linking tube; wherein the exhaust and intake cam profiles sequentially activate each respective actuator as the respective cam rotates, thereby causing the hydraulic fluid to flow out of the respective actuator assembly, through the respective like-numbered linking pipe, and into the respective like-numbered follower assembly, which in turn causes the respective follower to move the respective like-numbered exhaust or intake valve from a first one of an open position or a closed position to the other of the open position of the closed position.

10. A valve actuator system for an engine in accordance with claim 9, wherein: the first gear train is a planetary gear set further comprising a sun gear fixedly mounted on the power shaft to rotate with the power shaft; a first ring gear mounted in the frame around the power shaft to be coaxial with the shaft axis; a first planet gear carrier mounted in the frame to be rotatable about the shaft axis; and a first plurality of planet gears rotatably mounted on the first planet gear carrier, each first planet gear simultaneously rotationally engaging the sun gear and the first ring gear; wherein the exhaust cam is fixedly mounted to the first planet gear carrier to rotate with the first planet gear carrier; and the second gear train is a planetary gear set further comprising the sun gear fixedly mounted on the power shaft; a second ring gear mounted in the frame around the power shaft to be coaxial with the shaft axis; a second planet gear carrier mounted in the frame to be rotatable about the shaft axis; and a second plurality of planet gears rotatably mounted on the second planet gear carrier, each second planet gear simultaneously rotationally engaging the sun gear and the second ring gear; wherein the intake cam is fixedly mounted to the second planet gear carrier to rotate with the second planet gear carrier.

11. A valve actuator system for an engine in accordance with claim 10, wherein: the first ring gear is constrained by the frame to move in an arc around the power shaft, the second ring gear is constrained by the frame to move in an arc around the power shaft, and the system further comprises a first timing lever extending from the first ring gear that can rotate the first ring gear about the shaft axis; and a second timing lever extending from the second ring gear that can rotate the second ring gear about the shaft axis; wherein moving the first timing lever in a first arc around the shaft axis varies the valve timing of the exhaust valves; wherein moving the second timing lever in a second arc around the shaft axis varies the valve timing of the intake valves; and the valve timing of the exhaust valves may be varied independently from the valve timing of the intake valves.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Reference is made to the following drawings for a more complete description of the four previously presented embodiments of the invention:

(2) FIG. 1 is a schematic view of a valve actuator system in accordance with one aspect using a single cam to operate multiple valves;

(3) FIG. 2 is another schematic view, further illustrating components comprising the valve actuator system of FIG. 1;

(4) FIG. 3 is a cross-section side view of a valve actuator system in accordance with another aspect, wherein the system includes two cams and a set of planetary gears;

(5) FIG. 4 is a top view showing the general arrangement of the components in a planetary gear reduction system in accordance with one embodiment;

(6) FIG. 5 is a schematic view showing the fluid lines connecting the cam actuators to the valve followers for all intake or exhaust valves in an engine configuration of five cylinders surrounding a central power shaft wherein the cylinder centerlines are parallel to the centerline of the power shaft in accordance with another embodiment;

(7) FIG. 6 is a cross-section side view of a valve actuator system in accordance with yet another aspect, wherein the system includes two cams and a set of linear reduction gears; and

(8) FIG. 7 is a cross-section side view of a valve actuator system in accordance with a further aspect, wherein the system includes two cams and an alternative set of planetary gears having a different arrangement from that shown in FIG. 3.

DETAILED DESCRIPTION

(9) Referring now to the drawings, wherein like reference numbers are used herein to designate like elements throughout, the various views and embodiments of a valve actuator system using a single cam to operate multiple valves are illustrated and described. Also other embodiments of this valve actuator system are described. The figures are not necessarily drawn to scale, and in some instances the drawings have been exaggerated and/or simplified in places for illustrative purposes only. One of ordinary skill in the art will appreciate the many possible applications and variations based on the following examples of possible embodiments.

(10) Referring now to FIGS. 1 and 2, there is illustrated an exemplary embodiment of a valve actuator system 100 in accordance with one aspect. Referring first to FIG. 1, in the illustrated embodiment four valve actuators 101 are arranged radially about a single cam 102. Each actuator 101 is linked to its respective valve follower 103 by a small linking tube 104, all of which are filled with a hydraulic fluid 116. The follower 103 in turn causes the valve 105 to open and close in the same manner as the cam surface directs. Hydraulic fluid 116 (e.g., engine lubricating oil) transfers the force of the cam 102 from the actuator 101 to the follower 103 via the fluid-filled tube 104. In FIG. 1, one valve (denoted 105) is shown in the open position while all others are shown in the closed position. A more detailed description of the components and their operation is illustrated in FIG. 2.

(11) Referring now also to FIG. 2, the cam 102 is connected to the engine crankshaft or other element (not shown) through a gear, belt, chain or other means so the cam causes the valve 105 to open and close in proper timing with the piston operation. In FIG. 2, the valve 105 is shown in the closed position. The actuator 101 comprises an actuator housing 106 that is mounted in a fixed position with relation to the cam 102. One open end 107 of the housing 106 permits a plunger 108 to slide back and forth as the cam 102 forces it to open the valve 105 or permits it to return to the closed position. The plunger 108 fits snugly within the actuator housing 106 to prevent hydraulic fluid 116 from leaking unnecessarily past the housing 106. The other end 110 of the actuator housing 106 connects with the linking tube 104. The tube 104, actuator 101 and follower 103 are filled with a hydraulic fluid 116.

(12) Referring still to FIG. 2, the distant end of the linking tube 104 connects with the valve follower housing 111. The follower housing 111 is mounted in a fixed position in relation to the engine structure 115 around the valve 105. As the cam 102 pushes the actuator plunger 108 into the actuator housing 106, hydraulic fluid 116 is forced into the linking tube 104 and into the valve follower housing 111, forcing the valve plunger 112 to extend and open valve 105. The valve plunger 112 may be the same size as the actuator plunger 108 to replicate the motion produced by the cam 102, or it may be larger for less motion than the motion of actuator plunger 108, or it may be smaller to magnify the motion produced for actuator plunger 108 by the cam 102.

(13) Hydraulic fluid 116 may be supplied to the valve actuator system 100 from a source 117, which may be the engine lubricating system, through supply tube 113. A check valve 114 permits flow of fluid into the valve actuation system 100, but it prevents fluid from being forced back into the fluid source 117 while the valve 105 is forced open. The hydraulic fluid supply pressure keeps the valve plunger 112 against the valve 105, and the cam plunger 108 against the cam 102. The supply pressure is kept lower than the pressure required to open the valve 105 so that the valve is only open when the cam 102 forces the cam plunger 108 into the actuator housing 106. There is essentially no flow of hydraulic fluid 116 from the system 100. This feature keeps power loss to a minimum. The hydraulic fluid supply 117 replaces any seepage around the actuator plunger 108 and the valve plunger 112. There is no fluid accumulator in the valve actuation system 100. The hydraulic fluid 116 simply flows from the actuator housing 106 to the follower housing 111 and back again.

(14) Referring now to FIG. 3, there is illustrated a cross-section side view of a valve actuator system 300 in accordance with another embodiment (second embodiment). The system 300 includes two cams, a first cam 320 for operating all exhaust valves and a second cam 322 for operating all intake valves, and two sets of planetary gears 301a, 301b for matching the operation of the respective cams with the rotation of the central power shaft of the engine. A central shaft 315 is connected rotationally in concert with the crankshaft (or power shaft) of the engine. A single sun gear 316 fixedly connected to the central shaft 315 drives two sets of planetary gears (denoted, respectively, with a and b) to drive the exhaust and intake cams 320, 322 at the correct rotational speed. In this application, the ring gears 318a, 318b do not rotate except to vary valve timing.

(15) Referring now to FIG. 4, a typical set 301 of planetary reduction gears is illustrated as may be used in the disclosed embodiments. In each set of planetary gears 301, a sun gear 316 on a shaft 315 is in geared engagement with a set of multiple (in this case, three) planetary gears 317 that are concurrently in geared engagement with an enclosing ring gear 318. The planetary gears 317 are rotatably attached through bearings to a carrier 319, which carrier may also be rotatable around the shaft 315. In various configurations, either the planet gears 317, the ring gear 318 or the planet carrier 319 may be constrained against rotation to produce a rotational output from the remaining components when driven by the sun gear 316. It will be appreciated that FIG. 4 is intended only to illustrate the general layout of a planetary gear set, and the particular gear sizes and gear ratios illustrated in FIG. 4 are not necessarily the gear sizes or gear ratios used in the embodiments described herein.

(16) Returning to FIG. 3, a first set of gears, 317a and 318a, and a first carrier 319a are used to drive the exhaust cam 320 by the sun gear 316. In the illustrated embodiment, the exhaust cam 320 is fixedly mounted directly on the exhaust carrier 319a. Unlike the sun gear 316, which is fixed to the central shaft 315 to rotate with the central shaft, the exhaust carrier 319a and the exhaust cam 320 are rotatably mounted on the central shaft 315 to allow independent rotation with respect to the central shaft (although the carrier 319a and the cam 320 must rotate together). Each exhaust planet gear 317a is rotatably mounted on an axle bearing 302a of the exhaust carrier 319a, and is simultaneously engaged on the inward side by the sun gear 316 and on the outward side by the exhaust ring gear 318a. Relative rotational movement between the sun gear 316 and the ring gear 318a causes the planet gears 317a to simultaneously rotate on the axle bearing 302a of the carrier 319a and revolve around the sun gear. This revolution of the planet gears 317a causes the carrier 319a to rotate around the shaft 315. The sizes of the gears 317a and 318a are determined by the requirement for the exhaust cam 320 to rotate at half the rotational speed of the central shaft 315. The exhaust cam 320 is used to actuate all exhaust valves. Exhaust valve actuators 101 are arranged radially about the central shaft 315 and the exhaust cam 320. The exhaust actuator 101 shown in FIG. 3 is in the compressed state for an open exhaust valve 105. An exhaust timing lever 321 extends outward from the exhaust ring gear 318a, and may be used to selectively rotate the exhaust ring gear to vary the exhaust valve timing.

(17) Referring still to FIG. 3, the component arrangement for operation of intake valves is similar to the one for operation of exhaust valves previously described. A second set of gears, 317b and 318b, and a second carrier 319b are used to drive the intake cam 322 by the sun gear 316. The intake cam 322 is fixedly mounted directly on the intake carrier 319b. The intake carrier 319b and the intake cam 322 are rotatably mounted on the central shaft 315 to allow independent rotation with respect to the central shaft (although the carrier 319b and the cam 322 must rotate together). The intake planet gear 317b is rotatably mounted on an axle bearing 302b of the intake carrier 319b, and is simultaneously engaged on the inward side by the sun gear 316 and on the outward side by the intake ring gear 318b. Relative rotational movement between the sun gear 316 and the intake ring gear 318b causes the intake planet gears 317b to simultaneously rotate on the axle bearing 302b of the intake carrier 319b and revolve around the sun gear. This revolution of the intake planet gears 317b causes the intake carrier 319b to rotate around the shaft 315. The sizes of the gears 317b and 318b are determined by the requirement for the intake cam 322 to rotate at half the rotational speed of the central shaft 315. The intake cam 322 is used to actuate all intake valves. Intake valve actuators 101 are arranged radially about the central shaft 315 and the intake cam 322. The intake valve actuator 101 shown in FIG. 3 is in the extended state indicating a closed intake valve 105. It should be noted that in the illustrated embodiment, the intake cam 322 leads the exhaust cam 320 by approximately 90 degrees. An intake timing lever 323 extends outward from the intake ring gear 318b, and may be used to vary intake valve timing (independently of the exhaust valve timing). The two timing levers 321, 323 are shown in the same position for illustration purposes only.

(18) The valve actuator assembly 300 may include a housing fabricated in two parts, e.g., an upper housing 325 and a lower housing 327, to permit installation and orientation of components and verification of the configuration. In the illustrated embodiment, the respective actuator housings 106 of the intake valve actuator 101 and the exhaust valve actuator 101 are installed and oriented to the respective housing parts 325, 327 at fixed locations such that the outlet ports to the linking tubes 104 remain at respective fixed locations and respective fixed orientations relative to the housing 300. Hydraulic oil 116 may be provided through the fitting 324 in the upper housing 325 at the top of the central shaft 315 for lubrication of the components. It is anticipated that all hydraulic oil 116 including oil for lubrication and purging air bubbles will be returned to a collection system through openings 326 at the bottom of the lower housing 327. Similar provisions can be made with the follower installation.

(19) Referring now to FIG. 5, a schematic diagram is provided of a valve actuator system 500 in accordance with another embodiment suitable for use on a four-cycle, five-cylinder piston engine 502 with the cylinders 504-n arranged radially around the central power shaft 315 that controls piston motion. For purposes of illustration, only one cam 102 is shown, and each cylinder 504-n is provided with only one valve follower 103-n, but it will be appreciated that multiple cams may be placed on the shaft as previously described (e.g., FIG. 3) to actuate multiple types of valves per cylinder. The cam 102 is operatively connected to the central power shaft 315 to rotate with the power shaft. The cylinders 504-n in this embodiment are sequentially numbered 504-1, 504-2, 504-3, 504-4 and 504-5 in clockwise order and the cam 102 also rotates clockwise. Each cylinder 504-n is provided with a corresponding valve follower 103-n to be actuated by the cam 102 in order to open a corresponding valve (not shown) on the cylinder. Valve actuators 101-n are arranged radially about the central shaft 315 and the cam 102. The dash-numbers on the valve actuators 101-n indicate the dash-number of the corresponding valve follower 103-n to which that the respective valve actuator 101-n is linked (e.g., actuator 101-1 is linked to follower 103-1, actuator 101-2 is linked to follower 103-2, etc.). The firing order for this arrangement is (1), (3), (5), (2), (4). The dashed lines 104-n indicate the corresponding hydraulic tube connections between the respective valve actuators 101-n and the corresponding valve followers 103-n. The particular routes shown for the hydraulic lines 104-n are for illustration only; however, the interconnections are specific.

(20) Valve actuation systems incorporating an integrated reduction gear set and multiple cam actuators with one or two cams as described in these embodiments can be expected to offer significant advantages over the current technology. Independent intake and exhaust valve timing are easily achieved. Such valve actuation systems can be designed, constructed and installed as a single unit in various locations and orientations. In many installations, the installation should be able to avoid the use of timing belts and timing chains with their risk of failure and requirements for replacement. Such valve actuation systems do not require lengthy camshafts with multiple cams and their location requirements; thereby freeing up design features not available in current technology engines. Such valve actuation systems can be especially advantageous with non-traditional cylinder arrangements, such as those illustrated in FIG. 5. Achieving an oil-free upper cylinder head will simplify the installation of spark plugs and their wiring. It avoids the problem of oil leaks that now occur with valve covers.

(21) Referring now to FIG. 6, there is illustrated a valve actuation system 600 in accordance with another embodiment (third embodiment). Valve action system 600 is similar to the system 300 previously described, except that each set of planetary reduction gears 301 is replaced by a set of double idler gears mounted on a lever. The assembly housing 635, 637 is also modified to accommodate the different gear arrangement. If multiple cams are required, then separate gear trains may be provided for each cam, but all cams may be driven by the same power shaft.

(22) In the illustrated embodiment, two cams 633 and 636 are provided, the cams being driven, respectively, by an a gear train and a b gear train. In this embodiment, the sun gear 316 of FIG. 3 is replaced by a central drive gear 628 that drives both gear trains. The central drive gear 628 is fixed to the power shaft 315 and rotates with it. The a gear train includes a two-part idler gear 629a having two coaxial gear portions, a larger portion 610a and a smaller portion 612a, wherein each portion has a different diameter. The larger gear portion 610a of the idler gear 629a engages the central drive gear 628 and rotates about the bearing 630a on an exhaust timing lever 631a. The number of teeth on the larger portion 610a of the idler gear 629a is twice the number of the teeth on the drive gear 628, resulting in a 2:1 gear ratio. Thus, the idler gear 629a rotates at half the rotational speed but in opposite directions as the drive gear 628 and the central shaft 315. The smaller portion 612a of the idler gear 629a engages the gear section 632 of the exhaust cam 633. The exhaust cam 633 rotates freely about the central shaft 315. The smaller portion 612a of the idler gear 629a and the gear section 632 have the same number of teeth, resulting in a 1:1 gear ratio, so that both rotate at the same rotational speed but in opposite directions. The result is that the exhaust cam 633 rotates around the central shaft 315 in the same direction that the central shaft rotates, but at one-half the rotational speed.

(23) During operation of the a gear train, the exhaust timing lever 631a is normally held in a fixed position; however, the timing lever can be moved in an arc around the central shaft 315 to vary the exhaust valve timing. In the illustrated embodiment, one end portion of the timing lever 631a (e.g., the right end portion in FIG. 6) is constrained by the upper housing 635 (constraint not visible) to rotate about the central shaft 315. An exhaust timing actuator connection 634 extends from the other end of the timing lever 631a, and the gear bearing 630a is mounted on the timing lever between the two ends. To vary the exhaust timing, the timing lever 631a may be selectively rotated about the central shaft 315 by moving the timing actuator connection 634 in an arc. This arcing movement of the timing lever 631a causes the position of gear bearing 630a (upon which the idler gear 629a is mounted) to move in a similar arc about the central shaft 315 (while the idler gear stays in engagement with the central drive gear 628 and the gear section 632), thereby advancing or retarding the relationship between the angular position of the exhaust cam 633 and the angular position of the central drive gear 628 and power shaft 315 to adjust the exhaust timing.

(24) Gear components of the b gear train (denoted with b) that drive the intake cam 636 may be substantially similar to the parts used to drive the exhaust cam 633. In some embodiments, the intake cam 636 may be identical to the intake cam 633, but in other embodiments it may be modified to better meet the requirements of intake valves as opposed to those of exhaust valves. The b gear train includes a two-part idler gear 629b having two coaxial gear portions, a larger portion 610b and a smaller portion 612b, wherein each portion has a different diameter. The idler gear 629b may be identical to the idler gear 629a, but this is not required, provided each gear produces the appropriate gear ratios. The larger gear portion 610b of the idler gear 629b engages the central drive gear 628 and rotates about the bearing 630b on an intake timing lever 631b. The number of teeth on the larger portion 610b of the idler gear 629b is twice the number of the teeth on the drive gear 628, resulting in a 2:1 gear ratio. Thus, the idler gear 629b rotates at half the rotational speed but in opposite directions as the drive gear 628 and the central shaft 315. The smaller portion 612b of the idler gear 629b engages the gear section 638 of the intake cam 636. The intake cam 636 rotates freely about the central shaft 315. The smaller portion 612b of the idler gear 629b and the gear section 638 have the same number of teeth, resulting in a 1:1 gear ratio, so that both rotate at the same rotational speed but in opposite directions. The result is that the intake cam 636 rotates around the central shaft 315 in the same direction that the central shaft rotates, but at one-half the rotational speed.

(25) During operation of the b gear train, the intake timing lever 631b is normally held in a fixed position; however, the timing lever can be moved in an arc around the central shaft 315 to vary the exhaust valve timing. In the illustrated embodiment, one end portion of the timing lever 631b (e.g., the right end portion in FIG. 6) is constrained by the lower housing 637 (constraint not visible) to rotate about the central shaft 315. An intake timing actuator connection 639 extends from the other end of the timing lever 631b, and the gear bearing 630b is mounted on the timing lever between the two ends. To vary the intake timing, the timing lever 631b may be selectively rotated about the central shaft 315 by moving the timing actuator connection 639 in an arc. This arcing movement of the timing lever 63b causes the position of gear bearing 630b (upon which the idler gear 629b is mounted) to move in a similar arc about the central shaft 315 (while the idler gear stays in engagement with the central drive gear 628 and the gear section 638), thereby advancing or retarding the relationship between the angular position of the intake cam 636 and the angular position of the central drive gear 628 and power shaft 315 to adjust the intake timing. It will be appreciated that this arrangement allows the exhaust valve timing and the intake valve timing to be adjusted independently of one another.

(26) Referring now to FIG. 7, there is illustrated a valve actuation system 700 in accordance with yet another embodiment (fourth embodiment). The embodiment of FIG. 7 is substantially similar to the embodiment of FIG. 3 (second embodiment) except that the planetary gear set uses a different configuration to achieve the desired rotational speed of the cams. In particular, in this fourth embodiment the ring gears rotate continuously and there is no rotation of the planetary gear carrier except to change valve timing, whereas in the second embodiment of FIG. 3 the planetary gear carrier rotates continuously and there is no rotation of the ring gear except to change valve timing. This arrangement of fixed and rotating gears may permit a greater range of valve timing than the configuration in the second embodiment. Changes in the upper and lower housing 735, 737 from the second embodiment are also made to accommodate the differences in cam/gear interfaces and addition of bearings between the cams and the central shaft.

(27) In the valve actuation system 700, the exhaust cam 720 and the intake cam 722 are driven by separate gear trains (denoted a and b) similar to those previously described. A sun gear 316 is fixed to a central shaft 315 to rotate with the central shaft. The sun gear 316 engages a plurality of planet gears 717a and 717b from both gear trains. The planet gears 717a are rotatably mounted on axle bearings 702a of a first planetary gear carrier 719a, and the planet gears 717b are rotatably mounted on axle bearing 702b of a second planetary gear carrier 719b. An exhaust timing lever 721 extends from the planetary gear carrier 719a, and an intake timing lever 723 extends from the planetary gear carrier 719b. The timing levers 721, 723 prevent the rotation of the respective planetary gear carriers 719a, 719b except to change valve timing as further described herein.

(28) Each cam 720, 722 is fixedly attached to a respective ring gear 718a, 718b. In some embodiments, each cam and its respective ring gear are separately formed pieces connected together, whereas in other embodiments the two elements may be formed integrally as a single piece. Each cam 720, 722 and its connected ring gear 718a, 718b are rotatably mounted on the central shaft 315 to allow independent rotation with respect to the central shaft (although each cam/ring gear pair 720/718a and 722/718b must rotate together). Thus, each cam 720, 722 rotates with the same rotational speed as its respective ring gear 718a, 718b.

(29) The planet gears 717a engage the sun gear 316 on one side and the ring gear 718a on the other side. Since the planet gear carrier 719a is constrained from free rotation by the exhaust timing lever 721, then rotation of the sun gear 316 drives rotation of the ring gear 718a, and hence rotation of the exhaust cam 720. The sizes of the gears 717a and 718a are determined by the requirement for the exhaust cam 720 to rotate at half the rotational speed of the central shaft 315. Similarly, the planet gears 717b engage the sun gear 316 on one side and the ring gear 718b on the other side. Since the planet gear carrier 719b is constrained from free rotation by the intake timing lever 723, then rotation of the sun gear 316 drives rotation of the ring gear 718b, and hence rotation of the intake cam 722. The sizes of the gears 717b and 718b are determined by the requirement for the exhaust cam 722 to rotate at half the rotational speed of the central shaft 315.

(30) The exhaust cam 720 may be used to actuate all exhaust valves (not shown). Exhaust valve actuators 101 may be arranged radially about the central shaft 315 and the exhaust cam 720. The exhaust timing lever 721 may be moved in an arc around the shaft 315 to vary the exhaust valve timing in a manner substantially similar to that described in connection with the second embodiment and with FIG. 6 (third embodiment). Similarly, the intake cam 722 may be used to actuate all intake valves (not shown). Intake valve actuators 101 may be arranged radially about the central shaft 315 and the intake cam 722. The intake timing lever 723 may be moved in an arc around the shaft 315 to vary the intake valve timing.

(31) In the illustrated embodiment of FIG. 7, the cams 720, 722 rotate in the opposite direction from the central shaft 315 and sun gear 316. This directional difference is easily accommodated by rerouting the hydraulic lines 104-n (FIG. 5) from each actuator 101-n to the proper valve follower 103-n. A cam rotational speed of one-half the rotational speed of the central shaft 315 is accomplished when the diameter of the ring gears 718a, 718b is twice that of the sun gear 316.

(32) It will be appreciated by those skilled in the art having the benefit of this disclosure that valve actuator systems in accordance with the aspects and embodiments described herein may operate multiple valves with a single cam. It should be understood that the drawings and detailed description herein are to be regarded in an illustrative rather than a restrictive manner, and are not intended to be limiting to the particular forms and examples disclosed. On the contrary, included are any further modifications, changes, rearrangements, substitutions, alternatives, design choices, and embodiments apparent to those of ordinary skill in the art, without departing from the spirit and scope hereof, as defined by the following claims. Thus, it is intended that the following claims be interpreted to embrace all such further modifications, changes, rearrangements, substitutions, alternatives, design choices, and embodiments.