Diesel torque monitoring strategy based on ISO26262

ZHAO Jun-peng, ZHOU Wen-hua, LIANG Heng

(Department of Energy Engineering, Zhejiang University, Hangzhou 310027, China)

Abstract: In order to effectively limit the torque output of engine in function failure condition, the hazard analysis and risk assessment on diesel engine torque increase were carried out, and the safety goals were set, through the research on the product development process in ISO/DIS 26262. The actual torque calculation model based on the fuel injection control value, rail pressure and engine speed was designed to monitor the output torque, and the permitted torque calculation model was designed according to accelerator pedal position and engine speed redundant signals to limit the output torque, using Matlab/Simulink toolset. The model off-line simulation and bench test results indicate that the calculated actual torque is basically consistent with the output torque during the acceleration process of the engine, the non-driver demand torque increase is identified accurately during the failure of torque limitation module, then the injection cut off(ICO) is trigged and the engine is set to limp home. The output torque calculation and limitation accuracy can meet the functional safety requirement of engine torque.