K19 fuel pressure sensor 2897690 for Cummins diesel engine accessories

1. Semiconductor varistor type intake pressure sensor.

(1) Measuring principle of semiconductor piezoresistive pressure sensor The semiconductor piezoresistive pressure sensor uses the piezoresistive effect of semiconductor to convert pressure into corresponding voltage signal, and its principle is shown in Figure 8-21.

Semiconductor strain gauge is a kind of sensitive element whose resistance value will change correspondingly when it is pulled or pressed. The strain gauges are attached to the silicon diaphragm and connected to form a Wheston bridge. When the silicon diaphragm is deformed, each strain gauge is pulled or pressed and its resistance changes, and the bridge will have corresponding voltage output.

(2) Structure of the piezoresistive intake pressure sensor The composition of the semiconductor piezoresistive intake pressure sensor is shown in Figure 8-22. There is a silicon diaphragm in the pressure conversion element of the sensor, and the compression deformation of the silicon diaphragm will produce corresponding voltage signals. One side of the silicon diaphragm is vacuum, and the other side is introduced with the intake pipe pressure. When the pressure in the intake pipe changes, the deformation of the silicon diaphragm will change accordingly, and a voltage signal corresponding to the intake pressure will be generated. The greater the inlet pressure, the greater the deformation of the silicon diaphragm and the greater the output pressure of the sensor.

The semiconductor varistor type intake pipe pressure sensor has the advantages of good linearity, small structural size, high accuracy and good response characteristics.

1) Frequency detection type: the oscillation frequency of the oscillation circuit changes with the capacitance value of the pressure sensitive element, and after rectification and amplification, the pulse signal with frequency corresponding to the pressure is output.

2) Voltage detection type: the change of capacitance value of pressure sensitive element is modulated by carrier wave and AC amplifier circuit, demodulated by detector circuit, and then filtered by filter circuit to output voltage signal corresponding to pressure change.