Study on the measurement of dynamic characteristics for automotive electronic fuel injector

The dynamic characteristics of an electronic fuel injector have important effects on the accuracy of air-fuel ratio control in a manifold injected gasoline engine. In this paper a mathematical model to calculate the opening time and closing time of higher impedance injector is built. Under specific constructional dimension of the injector, the model equations are solved. Thus, the curve of the circuit current during a work circulation is obtained. According to the characteristics of the curve, a measurement system to get the opening time and closing time of the injector is developed. Under different working voltages, the opening time of the injector obtained from the model and the measurement system are compared, and the similar results show that the measurement system is successful.