Variable engine valve control system with hydraulic damper
AssigneeFord Motor Company
InventorsMichael M. Schechter, Michael B. Levin
Life of this patent
Estimating the term…
Abstract
A variable valve assembly, engine valve control system, and method of operation wherein the valve is hydraulically controlled and includes a valve piston subjected to fluid pressure acting on surfaces at both ends of the valve piston. The cavity at one end of the valve piston is connected to a source of high pressure fluid while the cavity at the other end is connected to a source of high pressure fluid and a source of low pressure fluid, and disconnected from each through action of controlling means such as solenoid valves. The valve assembly includes a damper to limit the velocity of the valve during a portion of the travel of the piston, particularly as the valve head lands on the valve seat.
Claims14
A hydraulically operated valve control system for an internal combustion engine, the system comprising:
- a high pressure source of fluid and a low pressure source of fluid;
- a cylinder head member adapted to be affixed to the engine and including an enclosed bore and chamber;
- a poppet valve shiftable between a first and second position within the cylinder head bore and chamber;
- a hydraulic actuator having a valve piston coupled to the poppet valve and reciprocable within the enclosed chamber which thereby forms a first and a second cavity which vary in displacement as the poppet valve moves;
- the cylinder head member having a high pressure port extending between the first and second cavities and the high pressure source of fluid, and a low pressure port extending between the first cavity and the low pressure source of fluid;
- a high pressure valve and a low pressure valve for respectively regulating the flow of fluid in the first cavity;
- control means cooperating with the high and low pressure valves for selectively coupling the first cavity to the high pressure and low pressure sources to oscillate the poppet valve in timed relation to engine operation, wherein during each oscillation, some of the high pressure fluid used to reciprocate the poppet valve is returned to the high pressure source, thereby allowing that the net fluid flow between the high pressure and low pressure sources may be substantially less than the volume swept by the valve piston;
- a damper housing, including a damper chamber, coupled to the cylinder head chamber and cooperating with the high and low pressure valves;
- and
- a damper piston biased against the poppet valve near a closed position of the poppet valve, the damper piston slidably enclosed within the damper chamber and including a pressure member disposed between the cylinder head chamber and the damper chamber having means for selectively restricting the flow of fluid between the damper chamber and the cylinder head chamber for restricting the velocity of the poppet valve during a portion of the poppet valve travel between the first and second positions within the cylinder head member.
A hydraulically operated popped valve assembly for an internal combustion engine comprising:
- a guide sleeve member including an enclosed bore and first chamber;
- a poppet valve shiftable between a first and second position within the guide sleeve bore and first chamber;
- a valve piston coupled to the poppet valve and reciprocable within the first chamber which thereby forms a first and a second cavity varying in displacement as the valve moves;
- the guide sleeve member having a high pressure port extending from the first and second cavities and a low pressure port, spaced from the high pressure port, extending from the first cavity;
- and
- damping means for restricting the velocity of the poppet valve during a portion of the poppet valve travel between the first and second positions within the cylinder head member;
- said damping means including a damper housing;
- said damper housing having a damper chamber coupled to the first chamber, and a damper piston slidably enclosed within the damper chamber and engageable with the poppet valve, said damper piston biased against the poppet valve near a poppet valve closed position and including a pressure member disposed between the first chamber and the damper chamber having means for restricting the flow of fluid from the damper chamber to the first chamber, for providing resistance to poppet valve motion during a portion of the poppet valve travel between the first and second positions.
A method of operating a hydraulically operated poppet valve assembly for an internal combustion engine, the poppet valve assembly having a guide sleeve member including an enclosed bore and first chamber, the poppet valve being shiftable between a first and second position within the guide sleeve bore and first chamber;
- a valve piston coupled to the poppet valve and reciprocable within the first chamber which thereby forms a first and second cavity which vary the displacement as the poppet valve moves;
- the guide sleeve member having a high pressure port extending from the first and second cavities and a low pressure port, spaced from the high pressure port, extending from the first cavity;
- damping means for restricting the velocity of the poppet valve during a portion of the poppet valve travel between the first and second positions within the cylinder head member;
- said damping means including a damper housing;
- said damper housing having a damper chamber coupled to the first chamber, and a damper piston means located within the damper housing and engageable with the poppet valve, for providing resistance to poppet valve motion during a portion of the poppet valve travel between the first and second positions;
- said method comprising:
- exposing the first cavity to a low pressure source of fluid to thereby initiate acceleration for a valve closing motion;
- disengaging the low pressure source of fluid to thereby terminate the acceleration of the poppet valve;
- exposing the first cavity to a source of high pressure fluid for a predetermined amount of time to thereby begin deceleration of the poppet valve whereby the poppet valve motion will not close the poppet valve completely;
- exposing the first cavity to the low pressure source of fluid for a predetermined time to thereby again initiate acceleration for the valve closing motion;
- and
- engaging the damping means to thereby limit the maximum velocity of the valve before final closure of the poppet valve.
Dependencies are inferred from the claim text.