Patent ID: 7128047
Filing Date: 2006-10-31
Classification: F02B,F02D,F02M,Y02T

Abstract:
1. Method of operating a four-stroke internal combustion engine including a variable volume combustion chamber defined by a piston reciprocating within a cylinder between top-dead center and bottom-dead center points, intake and exhaust passages, and intake and exhaust valves controlled during repetitive, sequential exhaust, intake, compression and expansion strokes of said piston comprising: providing exhaust events during which the exhaust valve is open for at least a portion of the exhaust stroke for expelling combusted gases from the combustion chamber; subsequent to the exhaust events during part load engine operation, providing simultaneous closure of the exhaust and intake valves for a period including a terminal portion of the exhaust strokes effective to trap and compress a portion of combusted gases within the combustion chamber, characterized by higher combustion chamber pressures at lower engine loads; and, providing intake events during which the intake valve is open for at least a portion of the intake stroke for ingesting fresh air into the combustion chamber.