Patent ID: 8307632

Claim:
A diesel engine comprising: a fueling system for injecting diesel fuel into combustion chambers where the fuel combusts to power the engine; an exhaust system through which gases created by combustion in the combustion chambers pass to atmosphere and which comprises an after-treatment device that treats the gases before leaving the exhaust system but at times requires regeneration by elevation of temperature of the gases to a regeneration temperature range; an engine control system for processing various data to control various aspects of engine operation including fueling performed by the fueling system and regeneration of the after-treatment device; the engine control system configured to execute instructions, during regeneration of the after-treatment device, said instruction comprising: a) determining a calculated quantity of post-injection fuel that by itself is sufficient to sustain regeneration but less than a threshold quantity that the engine control system uses to demarcate between causing and not causing a post-injection of fuel; b) incrementing a quantity of post-injected fuel that is currently stored in a buffer by the calculated quantity to yield an incremented quantity in the buffer; c) comparing the incremented quantity in the buffer to the threshold quantity; and d) if the incremented quantity in the buffer is at least equal to the threshold quantity, then causes the fueling system to post-inject into one or more of the combustion chambers, during a respective engine cycle for a respective combustion chamber, a quantity of fuel at least equal to the threshold quantity, but if the incremented quantity in the buffer is not at least equal to the threshold quantity causes the fuel system not to post-inject.