『Classification of air flow meters』Related information(clamp on meter|electromagnetic meter|venturi meterrotameter|orifice meter|ultrasonic flow meter|mass flow meter|coriolis mass flow meter|coriolis flow meter|magnetic flow meter|magmeter flow meter|magflow flow meter|mag meter flow meter|electromagnetic flow meter|vortex flow meter|turbine flow meter|thermal mass flow meter|thermal flow meter|rotameter flow meter)
1. What are the types of air flow meters?
The types of air flow meters include: wing plate air flow meter, vortex air flow meter, hot wire air flow meter, hot film air flow meter, and Karman vortex air flow meter. 1. Wing type air flow meter: This type of air flow meter measures air flow through one or more movable wing plates. When the airflow passes through, the wing plate will be displaced by the force, and this displacement is proportional to the air flow rate. By measuring the displacement of the wing plate, the size of the air flow can be determined. 2. Eddy current air flow meter: This type of flow meter mainly uses eddy current technology to measure air flow. When air flows through a vortex flowmeter, a series of ordered vortices are generated in the pipeline. There is a certain relationship between the frequency of vortices and the air flow rate. By measuring the vortex frequency, the air flow rate can be calculated. 3. Hot wire air flowmeter and hot film air flowmeter: Both types of flowmeters use thermal principles. The hot wire air flow meter measures the air flow rate by installing a heated thin metal wire inside the pipeline. When the air flows through the metal wire, the heat dissipation of the wire changes, and the air flow rate can be calculated by detecting the temperature change of the wire. The hot film air flow meter uses a heated thin film to detect air flow, and its principle is similar to that of a hot wire type. 4. Karman vortex air flow meter: This type of flow meter works using the Karman vortex principle. When air flows through a specific pipeline, a series of regular vortices are generated inside the pipeline. By detecting the frequency and number of these vortices, the air flow ra
2. What are the structural principles and classifications of air flow meters?
The working principle of a flow plate air flow meter (moving plate) is the interaction between the airflow torque M and the spring force N. Therefore, the flow plate works synchronously with the throttle valve. M> At N oclock, the board is open, there is more air and more fuel injection; 2. Working principle of hot wire air flow meter: Hot wire air flow sensors are mostly analog voltage signal sensors. When the engine is running and air flows through, heat is carried away. The resistance value of the hot wire RH decreases (PTC), and the resistance value of the cold wire RC increases (NTC), causing the bridge to lose balance and increase the bridge voltage. The amplifier then increases the compensation current IH flowing through the hot wire RH, restoring the normal temperature difference of the cold wire (100 degrees Fan laughed heartily). The increase of current IH will cause an increase in the voltage drop of RA. By measuring the voltage drop at both ends of RA, the amount of air flowing through can be determined, and the ECU can determine the required fuel injection quantity for the air-fuel ratio. 3. The working principle of a thermal air flow meter is basically the same as that of a hot wire air flow meter, except that the heating element is changed from a hot wire to a hot wire. Heat is formed by fixing the heating metal onto a resin film. This structure does not directly bear the force generated by air flow, which increases the strength of the heating element and improves the reliability of the
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