In order to improve the measurement accuracy of the injection rate of gasoline direct injection injectors

an injection rate measurement system was developed based on the principle of Zeuch method ;and a bench test and simulation calculation were performed on the stiffness of constant volume container

and air content in the measuring chamber that mainly affect the measurement accuracy. Results show that under the same injection conditions

the volumetric expansion of a low stiffness container is greater than that of a high stiffness container

so that the measured injection rate curve is relatively low

resulting in a decrease in measurement accuracy. When the air content in the measuring chamber is large

the increment of the pressure in the chamber decreases linearly

so that the amplitude of the pressure fluctuation increases and the freguency of the fluctuation decreases

resulting in a lower injection rate than the actual value coupled to the increase in fluctuation. Based on the research results

the revised and optimized fuel injection rate measurement system greatly improves the measurement accuracy and has high repeatability.