Feed forward Active Disturbance Rejection Control method for common-rail pressure control of diesel engine

The precise pressure control in common rail is the prerequisite for the excellent performance of common rail diesel engine. Because of the complexity of engine working conditions, conventional PID controller cannot meet the demand of flexible control of common rail pressure, especially when engine load changes largely and rapidly. To overcome the shortcomings of conventional PID, feed forward Active Disturbance Rejection Control (ADRC) has been applied in the common rail pressure control system. The high pressure common rail system layout is drawn and the principle of common rail pressure control is introduced. Four control functions are carried out: "Rail pressure set point calculation", "Feed forward controller", "ADRC controller", and "Flow to duty cycle". Finally, experimental results comparing between feed forward ADRC controller and conventional PID controller shows that: feed forward ADRC controller is more effective than conventional PID controller because it is smaller in error, quicker in track speed and stronger in anti-jamming ability. It ensures the common rail engine meet the strict specification of the law based on the good dynamic performance.