초록 ▼

A lost motion assembly for a valve of an internal combustion engine includes a cam, a cam piston which is spring biased to follow motion of the cam, a valve piston operatively engaged with a poppet valve, and an auxiliary piston. The cam piston, valve piston and auxiliary piston are in continuous co

A lost motion assembly for a valve of an internal combustion engine includes a cam, a cam piston which is spring biased to follow motion of the cam, a valve piston operatively engaged with a poppet valve, and an auxiliary piston. The cam piston, valve piston and auxiliary piston are in continuous contact with a fluid in an enclosed control chamber having a fixed volume, such that rotation of the cam causes displacement of the cam piston into the control chamber, which causes a corresponding displacement of at least one of the valve piston and auxiliary piston while the volume of fluid in the control chamber remains substantially constant.

대표청구항 ▼

1. An internal combustion engine valve operating system comprising:a cam;a cam piston which is spring-biased to follow motion of said cam;a valve piston operatively engaged with a poppet valve for opening the poppet valve; andan auxiliary piston movable with respect to an adjustable stop member;wher

1. An internal combustion engine valve operating system comprising:a cam;a cam piston which is spring-biased to follow motion of said cam;a valve piston operatively engaged with a poppet valve for opening the poppet valve; andan auxiliary piston movable with respect to an adjustable stop member;wherein said cam piston, valve piston and auxiliary piston are in continuous contact with a fluid in an enclosed control chamber having a fixed volume, such that displacement of said cam piston into said control chamber causes movement of said valve piston and/or said auxiliary piston, depending on the adjusted position of said adjustable stop member, while the volume of fluid in said control chamber remains substantially constant.2. The internal combustion engine valve operating system of claim 1, wherein said control chamber is formed within a housing, and said cam piston, valve piston and auxiliary piston are movably positioned in the housing.3. The internal combustion engine valve operating system of claim 2, wherein said adjustable stop member comprises a screw which is threadedly engaged with a holding nut attached to said housing, said screw being attached to a stepper motor to adjust the position of the screw, and said auxiliary piston being engaged with an auxiliary piston spring which biases said auxiliary piston away from said screw into said control chamber.4. The internal combustion engine valve operating system of claim 3, further comprising a valve spring biasing said poppet valve toward a closed position, said valve spring being stiffer than said auxiliary piston spring. 5. The internal combustion engine valve operating system of claim 2;wherein said control chamber is formed by interconnected passages which are drilled into said housing.6. The internal combustion engine valve operating system of claim 1, wherein said adjustable stop member is adjustable between a retracted position in which the poppet valve is deactivated and does not open when the cam rotates, and an extended position in which said auxiliary piston does not move so that the entire volume of fluid displaced by the cam piston causes movement of the valve piston for maximum valve opening.7. The internal combustion engine valve operating system of claim 6, wherein said adjustable stop member is infinitely adjustable by a stepper motor between said retracted and extended positions to vary the amount of valve lift during each cam rotation.8. The internal combustion engine valve operating system of claim 3, wherein said screw has a distal end which is abuttable against said auxiliary piston.9. The internal combustion engine valve operating system of claim 1, wherein said cam piston and auxiliary piston are hollow.10. The internal combustion engine valve operating system of claim 1, wherein said valve piston has a tapered head to facilitate soft seating of the valve.11. The internal combustion engine valve operating system of claim 3, wherein said holding nut is adjustable to pre-set the specific force induced against the auxiliary piston by the auxiliary piston spring. 12. The internal combustion engine valve operating system of claim 1, wherein said control chamber is formed within a housing, and said stop member comprises a screw with a threaded head portion which is threadedly engaged with said housing and said screw having a distal end which is engageable with said auxiliary piston to act as a stop.13. A lost motion assembly for a poppet valve of an internal combustion engine comprising:a cam;a cam piston which is spring-biased to follow motion of said cam;a valve piston operatively engaged with a poppet valve for opening the poppet valve; andan auxiliary piston;wherein said cam piston, valve piston and auxiliary piston are in continuous contact with a fluid in an enclosed control chamber having a fixed volume, such that rotation of said cam causes displacement of said cam piston into said control chamber, which causes a corresponding displacement of at least one of said valve piston and said auxiliary piston while the volume of fluid in said control chamber remains substantially constant; andwherein the allowable range of movement of said auxiliary piston is controllable such that the resulting valve lift of said poppet valve may be adjusted between a deactivated condition in which there is lost motion between the cam and the poppet valve, and a fully openable condition in which there is no lost motion.14. The assembly of claim 13, wherein said auxiliary piston is movable with respect to an adjustable stop member, and said resulting valve lift of said poppet valve may be controlled by adjusting said stop member. 15. The assembly of claim 14, wherein said control chamber is formed within a housing, and said cam piston, valve piston and auxiliary piston are movably positioned in the housing.16. The assembly of claim 15, wherein said adjustable stop member comprises a screw which is threadedly engaged with a holding nut attached to said housing, said screw being attached to a stepper motor to adjust the position of the screw, and said auxiliary piston being engaged with an auxiliary piston spring which biases said auxiliary piston away from said screw into said control chamber.17. The assembly of claim 16, further comprising a valve spring biasing said poppet valve toward a closed position, said valve spring being stiffer than said auxiliary piston spring.18. The assembly of claim 14, wherein said adjustable stop member is infinitely adjustable by a stepper motor to vary the amount of valve lift during each cam rotation.19. The assembly of claim 13, wherein said control chamber is formed within a housing, and said stop member comprises a screw with a threaded head portion which is threadedly engaged with said housing and said screw having a distal end which is engageable with said auxiliary piston to act as a stop.20. An internal combustion engine valve operating system comprising:a cam;a cam piston which is spring-biased to follow motion of said cam;a valve piston operatively engaged with a poppet valve for opening the poppet valve;an auxiliary piston movable with respect to an adjustable stop member; wherein said cam piston, valve piston and auxiliary piston are in continuous contact with a fluid in an enclosed control chamber having a fixed volume, such that displacement of said cam piston into said control chamber causes movement of said valve piston and/or said auxiliary piston, depending on the adjusted position of said adjustable stop member, while the volume of fluid in said control chamber remains substantially constant;wherein said control chamber is formed within a housing, and said cam piston, valve piston and auxiliary piston are movably positioned in the housing; andwherein said adjustable stop member comprises a screw which is threadedly engaged with a holding nut attached to said housing, said screw being attached to a motor which adjusts the position of the screw.