Fuel injection during negative valve overlap for stoichiometric diesel operations

A method of stoichiometrically operating a diesel-fueled internal combustion engine, the engine having one or more combustion cylinders, each cylinder having an associated piston, intake valve and exhaust valve, comprising:

• injecting diesel fuel into the cylinders during a compression stroke of the pistons, thereby providing a main fuel injection event;
• wherein the air-fuel ratio during the main fuel injection event is stoichiometric;
• advancing the exhaust valve lift and delaying the intake valve lift, such that a negative valve overlap period occurs between the end of the exhaust phase and the beginning of the intake phase of the engine cycle;
• determining whether intake manifold throttling has resulted in an undesired ignition delay;
• if the determining step results in an undesired ignition delay, determining a quantity and timing for a secondary fuel injection event, and injecting diesel fuel into the cylinders during the negative valve overlap period, thereby providing the secondary fuel injection event.