Patent ID: 6830020
Filing Date: 2004-12-14
Classification: F01L,F02D,Y02T

Abstract:
A diesel engine having cylinders and pistons defining expansible combustion chambers into which combustion supporting gas is compressed during compression strokes of the pistons for compression ignition and burning of injected fuel to drive a crankshaft, intake and exhaust valves actuated by crankshaft driven intake and exhaust camshafts for controlling the timed admission of air to and the discharge of exhaust from the combustion chambers, and the improvement comprising:a cam phaser on only the intake camshaft and operable to selectively retard timing of only the intake valves relative to the crankshaft to retard intake valve closing sufficiently to shorten the effective compression stroke, thereby reducing the effective compression ratio and lowering combustion temperatures in the combustion chambers for controlling exhaust emissions under predetermined conditions of operations; and a control effective to vary intake valve timing from a nominal setting to a retarded closing timing of up to 70 degrees of crankshaft rotation.