What are the types of intake manifold absolute pressure sensors?

[Hannah]

Intake manifold absolute pressure sensors include the following types: piezoresistive, capacitive, bellows-type, and surface acoustic wave-type. These sensors are devices that detect the absolute pressure in the intake manifold behind the throttle. They are connected to the intake manifold via a vacuum tube. As the engine operates under different speeds and loads, the sensor detects changes in the vacuum within the intake manifold. The internal resistance of the sensor changes accordingly, converting this into a voltage signal for the ECU to adjust fuel injection quantity and ignition timing. The intake manifold absolute pressure sensor detects changes in the absolute pressure within the manifold based on engine speed and load, converting these changes into a signal voltage sent to the engine control unit (ECU). The ECU then uses this signal voltage to control the basic fuel injection quantity.