EGR Cooler Performance Monitor - Heuristic Approaches Using Temperature Measurement

This paper investigates model free approaches to monitor the Exhaust Gas Recirculation (EGR) for a diesel engine equipped with EGR cooler and EGR cooler bypass valve. A conventional way of monitoring the EGR cooler is a model based approach which involves modeling the EGR cooler effectiveness and compares the modeled (estimated) EGR cooler effectiveness (or EGR cooler downstream temperature) and the measured EGR cooler effectiveness (or EGR cooler downstream temperature). The model based approach has the advantage of being portable across many different cooler configurations, but it requires modeling/calibration efforts and necessary temperature measurements.

The EGR cooler downstream temperature serves several roles. It can be used together with the fresh air temperature to calculate the charge air temperature. It also can be utilized to monitor the performance of the EGR cooler as mentioned above. The EGR cooler downstream temperature model can enhance the high frequency content of the temperature sensor, but its main use is for diagnostics. Instead of using the model, this paper proposes heuristic approaches to monitor the EGR cooler performance using the EGR cooler downstream temperature. The robustness of the proposed approaches is examined using experimental data and the applicability to EGR cooler performance monitor is illustrated.