A method of stoichiometrically operating a diesel-fueled internal combustion engine. During a main (conventional) fuel injection event, fuel is injected into the cylinders. The air-fuel ratio during this main fuel injection event is stoichiometric. The cylinders are operated by either advancing the exhaust valve closing or modifying the phasing of the exhaust and intake valve lift events, to achieve a negative valve overlap period between the end of the exhaust phase and the beginning of the intake phase of the engine cycle. Fuel is injected into the cylinders during the negative valve overlap period, which results in highly reactive fuel and reduces ignition delay during the main fuel injection event.
Darius Mehta; Chad P. Koci; Charles E. Roberts Jr.