Exhaust gas recirculation cooler protection system and method

摘要

A system and method of operating an exhaust gas recirculation (EGR) system of a vehicle includes controlling an EGR valve actuable between an EGR enabled position and an EGR disabled position, such that with the EGR valve in the EGR enabled position a portion of exhaust gas emitted from an engine is directed through an EGR cooler for recirculation into the engine, and with the EGR valve in the EGR disabled position the exhaust gas is not recirculated through the engine. An EGR coolant temperature is predicted based on measured engine speed, vehicle speed, outside ambient temperature, and commanded fuel level of the vehicle. The EGR valve is actuated to the EGR disabled position when the predicted EGR coolant temperature is equal or greater than an EGR coolant temperature threshold. The EGR coolant temperature is predicted without direct measurement of engine coolant temperature.

主权项

1. A method of operating an exhaust gas recirculation (EGR) system of a vehicle, the method comprising:
measuring an engine speed, a vehicle speed, an outside ambient temperature, and a commanded fuel level of the vehicle; controlling an EGR valve, wherein the EGR valve is actuable between an EGR enabled position and an EGR disabled position; wherein with the EGR valve in the EGR enabled position a portion of exhaust gas emitted from an engine of the vehicle is directed through an EGR cooler for recirculation into the engine; wherein with the EGR valve in the EGR disabled position the exhaust gas emitted from the engine is diverted from the EGR cooler such that the exhaust gas is not recirculated through the engine; wherein controlling the EGR valve further comprises:
predicting an EGR coolant temperature from the measured engine speed, vehicle speed, outside ambient temperature, and commanded fuel level;comparing the predicted EGR coolant temperature to an EGR coolant temperature threshold; andactuating the EGR valve to the EGR disabled position when the predicted EGR coolant temperature is equal or greater than the EGR coolant temperature threshold.