Engine power

fuel consumption and exhaust emission all depend on the accuracy of the air fuel ratio.Electronic fuel injection system makes it possible to keep the air-fuel ratio at the right point.The actual quantity of air entering the cylinder must be known so that the precise amount of fuel quantity can be supplied.The heat transfer process of hot-film air mass sensor is analyzed

and the principle of the hot-film air mass flowmeter is discusses

then a circuit is designed.By adjusting the initial potential and the nonlinear curve in circuit to make the hot-film mass air flowmeter adapted to the best power curve of different engines.According to the particular environment of vehicle

the auto-level integrated circuit is adopted in designing the hot-film air mass flowmeter.SMD-resistance is adopted to make the circuit adapted to the impact.The test results show that the accuracy and repeatability can all meet to the requirements.