The intake pressure sensor is mounted on the intake pipe. The pressure sensor, temperature compensation circuit and amplifier circuit are formed on a semiconductor substrate by using IC technology. In the middle of the silicon wafer, a square diaphragm is formed from the reverse side of the wafer, and the atmospheric pressure is transformed into stress by the diaphragm. Four P-type measuring resistors are formed on the surface of the diaphragm by diffusing impurities. They are connected according to the bridge circuit, and the stress on the diaphragm is transformed into the change of resistance by using the piezoresistive effect. Through the bridge circuit, they are output in the form of potential difference between the two terminals of the bridge circuit.
A real cavity is designed between the inside of the diaphragm and the silicon wafer to relieve the external stress, and the atmospheric pressure is measured based on the pressure of the real cavity.
The intake pressure sensor is an optional part, which is mainly installed on off-road vehicles. It is responsible for adjusting injection pulse width and ignition advance angle.