Claims
- 1. A homogeneous charge compression ignition engine comprising:
an engine housing defining a plurality of engine cylinders, a piston disposed in each cylinder and reciprocating between a top dead center position and a bottom dead center position; a fuel injector associated with each engine cylinder and being operable to inject fuel into a respective engine cylinder when said piston is closer to said bottom dead center position than to said top dead center position; at least one intake valve associated with each said engine cylinder; a cam being sized and positioned to mechanically actuate said at least one intake valve; and an electro-hydraulic assist intake actuator being sized and positioned to mechanically actuate said at least one intake valve.
- 2. The engine of claim 1 wherein said at least one intake valve has a cam determined opening time and a cam determined closing time; and
said electro-hydraulic assist intake actuator being capable of opening said at least one intake valve prior to said cam determined opening time and closing said intake valve after said cam determined closing time.
- 3. The engine of claim 1 including at least one cam actuated exhaust valve for each said engine cylinder, said at least one exhaust valve being operably coupled to an electro-hydraulic assist exhaust actuator.
- 4. The engine of claim 1 wherein said electro-hydraulic assist intake actuator includes a movable plunger;
said plunger being positioned to mechanically engage said intake valve; and said plunger is movable from a retracted position to an advanced position when said electro-hydraulic assist intake actuator is energized.
- 5. The engine of claim 1 wherein said cam is mechanically engageable with said at least one intake valve via a mechanical linkage that includes a rocker arm assembly.
- 6. The engine of claim 5 wherein said rocker arm assembly includes a pivot; and
said electro-hydraulic assist intake actuator is engageable a first distance from said pivot and said cam is engageable a second distance from said pivot.
- 7. A method of operating an engine comprising the steps of:
injecting fuel into an engine cylinder when a piston slidably disposed in the engine cylinder is closer to a bottom dead center position than a top dead center position; holding at least one gas exchange valve open, at least in part by a rotating cam mechanically engagable with said at least one gas exchange valve; and adjusting ignition timing, at least in part by actuating an electro-hydraulic assist actuator that is mechanically engageable with said at least one gas exchange valve.
- 8. The method of claim 7 wherein said at least one gas exchange valve is at least one intake valve; and
said step of adjusting ignition timing includes a step of retarding ignition timing, at least in part by activating said electro-hydraulic assist actuator to hold said at least one intake valve open beyond a cam determined intake valve closing time.
- 9. The method of claim 7 wherein said at least one gas exchange valve is at least one intake valve; and
said step of adjusting ignition timing includes a step of advancing ignition timing, at least in part by activating said electro-hydraulic assist actuator to open said at least one intake valve prior to a cam determined intake valve opening time.
- 10. The method of claim 7 wherein said at least one gas exchange valve is an at least one intake valve; and
including a step of expanding combustion duration, at least in part by activating said electro-hydraulic assist actuator to open said at least one intake valve prior to a cam determined intake valve opening time.
- 11. The method of claim 10 wherein said step of adjusting ignition timing includes a step of activating said electro-hydraulic assist actuator to hold said at least one intake valve open beyond a cam determined intake valve closing time.
- 12. The method of claim 7 wherein said at least one gas exchange valve is an at least one exhaust valve; and
said step of adjusting ignition timing includes a step of advancing ignition timing, at least in part by activating said electro-hydraulic assist actuator to open said at least one exhaust valve during an intake stroke of said cylinder piston.
- 13. The method of claim 7 wherein said at least one gas exchange valve is an at least one exhaust valve; and
including a step of expanding combustion duration, at least in part by activating said electro-hydraulic assist actuator to open said at least one exhaust valve during an intake stroke of said cylinder piston.
- 14. The method of claim 13 wherein said electro-hydraulic assist actuator is an electro-hydraulic assist exhaust actuator and said at least one gas exchange valve includes an at least one intake valve; and
wherein said step of expanding combustion duration includes a step of activating an electro-hydraulic assist intake actuator to hold said at least one intake valve open before a cam determined intake valve opening time.
- 15. The method of claim 7 wherein said electro-hydraulic assist actuator includes an electro-hydraulic assist intake actuator and said at least one gas exchange valve includes an at least one intake valve and an at least one exhaust valve; and
said step of adjusting ignition timing includes at least one of said electro-hydraulic assist intake actuator mechanically engaging said at least one intake valve with a first rocker arm assembly and an electro-hydraulic assist exhaust actuator mechanically engaging said at least one exhaust valve with a second rocker arm assembly.
- 16. A valve assembly comprising:
at least one gas exchange valve; a rotating cam being mechanically engageable with said at least one gas exchange valve; and an electro-hydraulic assist actuator including a movable plunger and being mechanically engageable with said at least one gas exchange valve.
- 17. The valve assembly of claim 16 wherein said gas exchange valve is an intake valve and said electro-hydraulic assist actuator is an electro-hydraulic assist intake actuator; and
including an electro-hydraulic assist exhaust actuator that is mechanically engageable with an at least one exhaust valve.
- 18. The valve assembly of claim 16 wherein said electro-hydraulic assist actuator is mechanically engageable with said at least one gas exchange valve via a rocker arm assembly.
- 19. The valve assembly of claim 18 wherein said electro-hydraulic assist actuator includes a plunger having a hydraulic surface that is exposed to pressure in a control passage; and
said electro-hydraulic assist actuator includes an electronically actuated flow control valve with a first position in which said control passage is connected to a source of high pressure and a second position in which said control passage is connected to a low pressure reservoir.
GOVERNMENT LICENSE RIGHTS
[0001] The U.S. Government has a paid-up license in this invention and the right in limited circumstances to require the patent owner to license others on reasonable terms as provided for by the terms of DE-FC05-97O R22605, awarded by the Department of Energy. In other words, this invention was made with Government support under DE-FC05-970R22605 awarded by the Department of Energy. The Government has certain rights in this invention.