Good product, good way

Oil Pressure Sensor

Definitions and materials

The oil pressure sensor of the car is an important device for detecting the oil pressure of the vehicle engine. The detected data can help control the normal operation of the engine.

The electronic oil pressure sensor is composed of a thick film pressure sensor chip, a signal processing circuit, a housing, a fixed circuit board device, and two leads (signal line and alarm line). The signal processing circuit is composed of a power supply circuit, a sensor compensation circuit, a zero adjustment circuit, a voltage amplifier circuit, a current amplifier circuit, a filter circuit, and an alarm circuit.

Classification

Semiconductor piezoresistive sensor
This type of sensor uses the piezoresistive effect of semiconductors. The strain sensitivity of ordinary semiconductor materials is better than that of metal materials. Using the piezoresistive effect of single crystal silicon on the basis of single crystal silicon, a component made of semiconductor technology, when the semiconductor is subjected to pressure, its resistance will change, thereby forming a signal output of pressure change. The commonly used piezoresistive sensors are four equivalent strain elements to form an electric bridge. When the pressure is changed, it is divided into two pairs to produce a change effect. One pair becomes larger and the other becomes smaller, resulting in an imbalance in the bridge. Enter a voltage signal that is proportional to the pressure. Its biggest features are high sensitivity, large measurement range, strong output signal, and easy integration. However, its ability to resist oil pollution and particulate effects is poor, and it must be isolated by a medium to achieve accurate results.

Traditional elastic strain sensor
This type of sensor is characterized by a wide measurement range, high accuracy, good stability, and long service life. It can withstand the effects of high temperature, high speed, high pressure, and vibration, so it is more suitable for automotive testing environments. Strain sensors usually consist of four bridge resistors. The opposite set of bridge arm resistors undergo a change in tension when subjected to pressure, while the other type is a change in pressure that affects the resistance and the magnitude of its signal. Equality and opposite signs increase the sensitivity of the sensor. The output signal amplitude of this kind of sensor has small changes. In the case of drastic changes in the temperature environment, temperature compensation is needed, but it is difficult.

Thick film pressure sensor
This sensor is a new type of force-sensitive sensor. It uses the piezoresistive effect of thick film resistors, and its strain resistance is a thick film ruthenate resistor with piezoresistive effect. It is directly printed and sintered on ceramic elastomers using thick film technology. After firing at high temperature, the strain resistance and the ceramic body are firmly combined, and there is no need to paste. This form avoids the disadvantages of common stress-type force-sensitive sensors that are prone to aging due to the sticking process. Thick film strain resistance has stable performance, high temperature resistance, and temperature coefficient is one order of magnitude smaller than that of diffused silicon.

Ceramic Piezoresistive Sensor
This type of sensor is a dry ceramic pressure sensor made of ceramic material through a special process. Ceramic is a high-quality material with high elasticity, corrosion resistance, wear resistance and vibration resistance. The thermal stability of ceramics is significantly better than the working range of thick film resistance sensors. Its temperature range can reach -40 ° C to 125 ° C, and it still has high accuracy and stability at high temperatures. Electrical insulation strength> 2kV, strong output signal and long-term stability. The working principle is: the measured pressure directly acts on the surface of the ceramic diaphragm, causing the ceramic diaphragm to deform, and the thick film resistor is printed on the back of the ceramic diaphragm to form an electric bridge. A proportional electrical signal related to pressure and voltage will be generated; at the same time, the signal will be divided according to the pressure range difference and compatible with inductive sensors. Through laser calibration, the sensor has temperature stability and time stability. The sensor comes with temperature compensation, which can contact with most media and ensure the detection effect. But its cost is high, and it takes time to promote.

Function and characteristics

The oil pressure sensor is installed on the main oil passage of the engine. When the engine is running, the pressure measuring device detects the pressure of the oil, converts the pressure signal into an electric signal and sends it to the signal processing circuit. The pressure signal is connected to the oil pressure indicator, and the ratio of the current passing through the two coils inside the oil pressure indicator is changed to indicate the engine oil pressure. The voltage signal amplified by voltage and current is also compared with the alarm voltage set in the alarm circuit. When the voltage is lower than the alarm voltage, the alarm circuit outputs an alarm signal and lights the alarm lamp through the alarm line.

The wiring method of the electronic oil pressure sensor is completely the same as the traditional mechanical sensor. It can replace the mechanical pressure sensor and directly connect with the automobile oil pressure indicator and the low-pressure alarm lamp to indicate the oil pressure of the diesel engine and provide a low-pressure alarm signal. Compared with traditional piezoresistive oil pressure sensors, electronic automobile oil pressure sensors have the advantages of no mechanical moving parts (that is, no contacts), high accuracy, high reliability, and long life, and meet the requirements of automotive electronics development .

Due to the harsh working environment of automobiles, the requirements for sensors are very strict. In the design of electronic automotive oil pressure sensors, not only the high-temperature, corrosion-resistant, high-precision pressure measurement device needs to be selected, and reliable performance and wide operating temperature range are selected. Components, and anti-interference measures need to be taken in the circuit to improve the reliability of the sensor.

Image

 

 

 

Product knowledge

No Related Product knowledge!

Good Methods

No Related Good Methods!

Contact message