Indicate torque estimation for turbocharged diesel engine based on the instantaneous speed

First the calculation formula of average indicated torque has been derived from the 1 order amplitude and phase of cylinder pressure. Then the linear relationship between 1 order cylinder pressure amplitude and firing order engine speed amplitude has been obtained by experimental study. Meanwhile, 1 order cylinder pressure phase can be calculated by intake pressure, 1 order cylinder pressure amplitude and 1 order combustion cylinder pressure phase. Finally by using DSP system, the real-time calculation of firing order engine speed amplitude can be realized. Experimental results show that the relative average estimation error is 3.07% in the rapid torque increase and decrease process.