What are the types of intake manifold absolute pressure sensors?

[LeJulianna]

There are various types of intake manifold absolute pressure sensors, which can be classified based on their detection principles into piezoresistive, capacitive, aneroid, and surface acoustic wave types. The most commonly used are piezoresistive and capacitive sensors. Below is a detailed introduction to these two types: 1. Piezoresistive intake manifold absolute pressure sensor: This sensor mainly consists of an absolute vacuum chamber, a silicon chip, and an IC amplification circuit. One side of the silicon chip is exposed to the vacuum chamber, while the other side is subjected to the pressure in the intake manifold. The pressure causes the silicon chip to deform. 2. Capacitive intake manifold absolute pressure sensor: This sensor is composed of an elastic diaphragm, output terminals, and a housing. It utilizes the capacitive effect to detect the absolute pressure in the intake manifold. The change in capacitance is proportional to the displacement of the elastic diaphragm, which depends on the gas pressure in the upper and lower chambers. The upper chamber of the elastic diaphragm is an absolute vacuum, while the lower chamber is connected to the intake manifold. Thus, the absolute pressure in the intake manifold can be detected by measuring the change in capacitance. The change in capacitance is then converted into a voltage signal by the measurement circuit and input to the ECU.