Study On A New Style Vane Air Flow Sensor

The Electronic Fuel Injection System (EFI) is the key electronic control system of the modern automobile. It can control the fuel injection and the duration of ignition according to the signals from sensors, which show the status of automobile, and the fuel will be burned near the ideal air-fuel ratio. Then the pollution will be reduced and energy will be saved. The automotive air flow sensor is the one of the most important sensors of the EFI. Its output influences the fuel injection directly. So it is of essential importance to study the air flow sensor, analyze the problems and present a new solution.The principles of the three general automotive air flow sensors are studied, and the advantage and the disadvantage are analyzed and compared in this thesis. Among these three sensors, the Vane air flow sensor is accepted by the automobile companies because of its low cost and simple structure. But the application is constrained seriously by its high pressure-loss and long response-time. After analysis, the structure can be improved and optimized to be a less pressure-loss and a shorter response-time.The mathematical model of the Vane air flow sensor is built in the thesis. According this model, the lager square of the wing, the lager pressure loss. And the lager inertial moment of the rotation part, the longer response time. Based on the analysis, the wing square reduction, the wing shape optimization and the material density reduction are presented to reduce the pressure lose and short the response time in the thesis. And a new style Vane air flow sensor is designed.A special analysis software is developed for the Vane air flow sensor. It simulates the new Vane air flow sensor, which presented in the thesis.According to the simulation and analysis, the performance improvement is verified in the new style Vane air flow sensor. The results of the thesis have some valuable reference and it can guide the design and optimization of the Vane air flow sensor.