The air flow sensor used in the electronic control fuel injection device should not only maintain the measurement accuracy over a wide measurement range, but also have excellent measurement response and can be measured.

In this range, the air flow rate of the sensor should be able to maintain a measurement accuracy of ☒~3. The ratio of the maximum value to the minimum value of the air flow rate inhaled by a gasoline engine is 40-50 in a natural intake system, and 60-70 in a supercharged system. When the allowable error is distributed to each component of the system, the allowable error of the air flow sensor is ☒~3. When the control precision of the air-fuel ratio (A/F) of the air and mixture inhaled by the engine is specified as ☑.0, the allowable error of the system is ☖~7. In the electronic controlled fuel injection device, the mass air flow sensor, which measures the amount of air absorbed by the engine, is one of the important components to determine the control precision of the system. According to their structure types, the common air flow sensors can be divided into blade (wing) type, core type, hot-wire type, hot film type, Karman vortex type, etc. There are many types of air flow sensors in the electronic controlled gasoline injection system. If the air flow sensor or circuit fails and the ECU does not get the correct intake signal, it will not be able to control the fuel injection properly, which will cause the mixture to be too thick or too thin, and the engine will not operate properly. In order to obtain the best concentration of the mixture under various operating conditions, the electronically controlled gasoline injection engine must accurately measure the amount of air inhaled into the engine at each moment, which is the main basis for the ECU to calculate (control) the amount of fuel injection. Ⅷ Karman Vortex Type Air Flow Sensor for Pressure Change Detection

Ⅶ Ultrasonic Karman Vortex Air Flow Sensor Ⅲ The Structure of the Valve Type Air Flow Sensor

Jet mass air flow sensor problems