Patent ID: 7036483

Claim:
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 for each cylinder the improvement comprising: an intake camshaft having first and second cam lobes of different profiles on the intake camshaft wherein the first and second cam lobes have respective intake valve opening profiles that are not advanced relative to a nominal profile, and further wherein the first cam lobe has a first intake valve closing profile and the second cam lobe has a second intake valve closing profile that is retarded relative to the first intake valve closing profile; and, a selection mechanism for selectively coupling one of the two cam lobes to respective intake valves, whereby the first intake valve closing profile effects a relatively high effective compression ratio and high combustion temperatures and the second intake valve closing profile effects a relatively low effective compression ratio and low combustion temperatures.