Internal-combustion engines – Poppet valve operating mechanism – Hydraulic system
Reexamination Certificate
2000-01-10
2001-01-16
Lo, Weilun (Department: 3748)
Internal-combustion engines
Poppet valve operating mechanism
Hydraulic system
Reexamination Certificate
active
06173684
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to a valve actuating apparatus for engines, and more particularly concerns a system for actuating and controlling reciprocating valves for the cylinders of an internal combustion engine.
2. Description of Related Art
Conventional piston type internal combustion engines typically utilize mechanically driven camshafts for operation of intake and exhaust valves, with fixed valve lift and return timing and duration. Electrically or hydraulically controlled valves for improved control of valve operation have also been used in order to improve fuel economy and reduce exhaust emissions.
For example, a variable engine valve control system is known in which each of the reciprocating intake or exhaust valves is hydraulically controlled, and includes a piston receiving fluid pressure acting on surfaces at both ends of the piston. One end of the piston is connected to a source of high pressure hydraulic fluid, while the other end of the piston can be connected to a source of high pressure hydraulic fluid or a source of low pressure hydraulic fluid, under the control of a rotary hydraulic distributor coupled with solenoid valves.
Another engine valve actuating system is known in which each cylinder is provided with a coaxial venturi shaped duct having inwardly facing vanes that hold an electro-mechanical valve actuator. When the electro-mechanical valve actuator receives a pulsed electrical signal, the actuator operates to reciprocate the valve.
While a camshaft driven intake or exhaust valve will typically open and close with a constant period as measured in crankshaft degrees, for any given engine load or rpm, there is a need for an indirect valve actuation system for internal combustion engines that can operate more rapidly, and that will open the valve at the same rate regardless of engine operating conditions. Ideally, a valve actuation system should match the optimum, maximum valve rate of operation at maximum speed of operation of an engine to provide a rapid, optimum valve operation rate. It would also be desirable to provide a valve actuation system for internal combustion engines offering a speed of operation that will allow greater flexibility in programming valve events, resulting in improved low speed torque, lower emissions, and better fuel economy. Conventional approaches to providing higher rates of valve opening and closing have used non-latching control valves commonly involving systems using either spool valves or poppet valves, neither of which provide for a high flow open area in a small, low inertia system or energy efficient latching mechanisms. It would be desirable to provide a valve actuation and control system with an electro-hydraulic valve system, having a high flow open area, low inertia of operation, a small size, and case of manufacture. The present invention meets these needs.
SUMMARY OF THE INVENTION
Briefly, and in general terms, the present invention provides for an intake/exhaust (I/E) reciprocating valve actuation and control system for the cylinders of an internal combustion engine, comprising I/E poppet valves moveable between a first and second position; a source of pressurized hydraulic fluid; a hydraulic actuator including an actuator piston coupled to the poppet valve and reciprocating between a first and second position responsive to flow of the pressurized hydraulic fluid to the hydraulic actuator; an electrically operated hydraulic valve controlling flow of the pressurized hydraulic fluid to the hydraulic actuator; and electronic control means generating electrical pulses to control the electrically operated valve.
In one presently preferred embodiment, the invention provides for a three way electrically operated valve controlling flow of the pressurized hydraulic fluid to the actuator, supplying pressure when electrically pulsed to open, magnetically latching, and dumping actuator oil to an engine oil sump when the valve is electrically pulsed to close. The electrically operated valve preferably comprises a three path rotary latched magnetic motor actuating a rotary valve portion having a housing, a rotor, and a stator receiving and supplying hydraulic fluid pressure to the rotor, which alternately directs the hydraulic fluid pressure to the valve cylinder for opening of the valve, or to return to the engine oil sump, for closing the valve.
In a presently preferred embodiment, the hydraulic actuator comprises a self-contained cartridge assembly including an actuator piston with means for damping motion of the actuator piston, limiting the actuator stroke to assure soft seating of the I/E valve, and to avoid overshoot during the engine valve opening stroke and the engine valve return stroke. In a currently preferred embodiment, the source of pressurized hydraulic fluid comprises an engine-driven pump supplying engine oil under pressure as the hydraulic fluid, an accumulator is used to provide a reservoir of high pressure fluid, and an engine oil sump for receiving return hydraulic fluid. An unloader valve limiting pump output pressure is also provided, along with a check valve preventing backflow from the engine oil sump. An accumulator is also preferably provided for storing a sufficient volume of pressurized hydraulic fluid to moderate the pump and unloader valve duty cycle. The unloader valve preferably comprises a pressure sensing valve that senses pump output pressure and opens when the pressure reaches a preset value, so that when the unloader valve is open, flow from the pump returns to the engine oil sump. The accumulator is also used to store energy primarily dissipated under deceleration by the brakes or as a compression brake by filling the accumulator during that time. The engine would use the torque from the wheels in reverse driving the hydraulic pump and filling the accumulator, thus recycling velocity energy that would normally be lost to wheel braking.
Thus, the hydraulic pump could be temporarily disconnected so that under high load, the valve train would run off stored accumulator energy. This would use more of the power lost during braking. In a presently preferred embodiment, the control means comprises a computer, and sensors are operatively connected to the computer, for monitoring engine variables, and for optimizing performance of the system.
These and other aspects and advantages of the invention will become apparent from the following detailed description and the accompanying drawings, which illustrate by way of example the features of the invention.
REFERENCES:
patent: D. 247717 (1978-04-01), Sturman et al.
patent: D. 258140 (1981-02-01), Sturman et al.
patent: 2232502 (1941-02-01), Wittman
patent: 2569800 (1951-10-01), Cataldo
patent: 3989066 (1976-11-01), Sturman et al.
patent: 4107546 (1978-08-01), Sturman et al.
patent: 4108419 (1978-08-01), Sturman et al.
patent: 4114647 (1978-09-01), Sturman et al.
patent: 4227489 (1980-10-01), Regamey
patent: 4232707 (1980-11-01), Sturman et al.
patent: 4270573 (1981-06-01), Sturman et al.
patent: 4409638 (1983-10-01), Sturman et al.
patent: 4501290 (1985-02-01), Sturman et al.
patent: 4516600 (1985-05-01), Sturman et al.
patent: 4541454 (1985-09-01), Sturman et al.
patent: 4544986 (1985-10-01), B{umlaut over (u)}chl
patent: 4614170 (1986-09-01), Pischinger et al.
patent: 4782426 (1988-11-01), DeCamp et al.
patent: 4799582 (1989-01-01), Lequesne
patent: 4810967 (1989-03-01), Yokoyama et al.
patent: 4811221 (1989-03-01), Sturman et al.
patent: 4857842 (1989-08-01), Sturman et al.
patent: 4930465 (1990-06-01), Wakeman et al.
patent: 4955348 (1990-09-01), Budde et al.
patent: 4974495 (1990-12-01), Richeson, Jr.
patent: 5022565 (1991-06-01), Sturman et al.
patent: 5058857 (1991-10-01), Hudson
patent: 5162710 (1992-11-01), Reinhart et al.
patent: 5190262 (1993-03-01), Woollatt
patent: 5197428 (1993-03-01), Hornby
patent: 5222714 (1993-06-01), Morinigo et al.
patent: 5251659 (1993-10-01), Sturman et al.
patent: 5255641 (1993-10-01), Schechter
patent: 5287829 (1994-02-01), Rose
patent: 5301875
Buehrle, II Harry W.
Clark Raymond C.
Gross Jarrid
Long Ron
Nist Lance E.
Fulwider Patton Lee & Utecht LLP
Lo Weilun
Paul, Esq. James W.
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