Abstract: The present invention, provides a strategy or method for injecting fuel in two distinct fuel injection events per engine cycle. The first injection event is main fuel injection, which occurs when the crankshaft is near top-dead center. The main injection event delivers a majority of the fuel needed to provide a majority of the power produced during combustion. The second injection event is post injection, which occurs shortly after the main fuel injection event. The post injection event provides a supplemental amount of fuel to the combustion chamber to reduce the rate of pressure rise while increasing, turbulence, mixing and cylinder pressure within the combustion chamber to reduce the formation of soot. In addition, the combination of the main fuel injection event and the post fuel injection event reduces engine noise by reducing heat release rates and the rate of combustion chamber pressurization.

Abstract: A cam phaser is mounted on the exhaust camshaft of a diesel engine and is operable to selectively advance timing of only the exhaust valves relative to a nominal position. The purpose of advancing timing of the exhaust valves is to advance valve closing sufficiently to shorten the effective exhaust strokes of the pistons and thus increase the trapped hot exhaust residuals. This occurs when the exhaust valves close earlier than piston top dead center in the normal exhaust stroke phase of engine operation. This increases the in-cylinder temperature so that combustion stability and hydrocarbon emissions are improved.