In-Cycle Closed-Loop Combustion Control for Pilot Misfire Compensation
Pilot injections are normally used for the reduction of diesel engine emissions and combustion noise. Nonetheless, with a penalty on the indicated thermal efficiency. The cost is reduced by the minimization of the pilot mass, which on its counterpart increases the risk of pilot misfire. However, pilot misfire can have a higher penalty on the indicated efficiency if it is not compensated adequately. This paper investigates how in-cycle closed-loop combustion control techniques can reduce the effects of pilot misfire events. By closed-loop combustion control, pilot misfire can be detected and compensated in-cycle. Based on the in-cycle misfire diagnose, three architectures are investigated. The first uses a cycle-to-cycle controller to set the main injection under each scenario. The second is a fully in-cycle controller with feedback from predictive models. The third approach investigates how the pilot misfire can be counteracted by a second pilot injection.