Car common rail pressure sensor, fuel pressure sensor, oil pressure sensor, air conditioning pressure sensor, air pressure sensor

Adaptability: Bosch Sensata and other products and most models; Full temperature compensation, stable, reliable, and durable

OE：（Automobile parts code）

The functions of the nine automotive pressure sensors are as follows:

1. High and low pressure sensors for vehicle air conditioners - measure the pressure of the condensate in the vehicle air conditioning system;
2. Brake pressure sensor - measures brake hydraulic or pneumatic pressure.
3. Fuel pressure sensor - used to measure the fuel pressure in the fuel pipe behind the fuel pump;
4. Common rail pressure sensor - measures the fuel pressure in the rail of the common rail injection system of a diesel engine;
5. Oil pressure sensor - used to measure the pressure of lubricating oil;
6. Air pressure sensor - used to measure the air pressure in the intake air, the rear end of the supercharged turbine, and the intake manifold;
7. Tire pressure sensor - measures the pressure inside the tire;
8. Cylinder pressure sensor - measures the pressure inside the cylinder;
9. Differential pressure sensor - measures the pressure difference between both ends of the exhaust particulate trap.

Car common rail pressure sensor, fuel pressure sensor, oil pressure sensor, air conditioning pressure sensor, air pressure sensor

Purpose of common rail pressure sensor:
"High pressure oscillations" can occur when the high-pressure fuel pump supplies high-pressure fuel, and common rail pipes (also known as "high-voltage storage devices") can effectively eliminate this high pressure shock wave. ". This ensures that the injection pressure remains momentarily stable when the fuel injector is turned on. The common rail pipe also functions as a fuel distributor. The common rail pressure sensor is installed on the common rail pipe to measure the fuel supply pressure. Realize closed-loop control of fuel pressure.
The so-called closed-loop control: The ECU controls the opening of the fuel metering unit based on the theoretical rail pressure (i.e., the target rail pressure, sometimes referred to as the rated rail pressure, rail pressure demand, etc.) calculated from the sensor under the current operating conditions of the engine to achieve rail pressure control, and relies on the actual rail pressure detected by the rail pressure sensor to compare and correct with the theoretical rail pressure to achieve closed-loop control.

Operating process of common rail pressure sensor:
The Common rail pressure sensor is installed on the common rail pipe. Its function is to measure the actual pressure signal in the common rail pipe in real time, convert the fuel pressure in the rail into a voltage signal and transmit it to the ECU. The ECU performs feedback control on the pressure control valve (PCV) or the fuel inlet metering valve, and adjusts the oil pressure to stabilize it at the target value by increasing or decreasing the fuel supply volume.

Structure and working principle of common rail pressure sensor:
The rail pressure sensor is composed of three parts: a silicon membrane, a bridge, and an amplifier circuit. When the pressure in the rail causes the shape of the silicon membrane to change (approximately 1 mm at 150 MPa), the resistance value of the resistor layer connected to the membrane will also change. The changed resistance value will cause a change in the voltage at the output terminal through the 5V bridge (Huisden bridge). Through the processing of the amplification circuit, the voltage output at the new terminal will change between 0-5V, and the ECU will use this voltmeter.
The working principle of a differential pressure sensor is that the measured pressure directly acts on the membrane of the sensor, causing the membrane to produce a micro displacement proportional to the water pressure, causing the capacitance value of the sensor to change, and using electronic circuitry to detect this change, converting and outputting a standard measurement signal corresponding to the pressure.

Functions of various common rail sensors:
Rail pressure sensor is an indispensable sensor for diesel common rail engines. It is also a crucial sensor.

1. Oil pressure sensor:
The oil pressure sensor is also referred to as the oil pressure switch and oil sensor plug. The sensor uses ceramic capacitance technology to measure the oil pressure in the oil circuit, achieving extremely high accuracy at low pressure points. The data error fluctuates around 1.2%, the response time is less than 2 milliseconds, and the pressure detection range is 50-1150 kpa. However, this type of sensor requires a high level of oil cleanliness. Due to the fact that vehicles often drive at high speeds under various road conditions, including off-road sections, the actual working environment of the oil pressure sensor is very poor, with high temperatures as high as 110 degrees Celsius and low temperatures below - 30 degrees Celsius, and often subjected to shock, vibration, corrosion, and overload.

2. Intake pressure sensor
There are many types of intake pressure sensors, such as varistors and capacitors. However, most vehicles use varistors because of their advantages such as sensitive response, high detection accuracy, small size, and convenient installation.
The intake air pressure sensor (MAF) is also known as the intake manifold pressure sensor. The data measured by this sensor is the difference between the actual vacancy in the intake manifold and atmospheric pressure. The engine control computer can accurately calculate the true idle degree based on this voltage value and correct the injection pulse width. The sensor can be directly connected to the true vacancy of the intake manifold. When the ignition switch is turned on, the engine computer electronic control unit reads the voltage or signal frequency of the intake pressure sensor and automatically treats this data as atmospheric pressure.
In an engine control system equipped with an intake pressure sensor, when the engine is started, the engine ECU can calculate fuel based on the intake pressure signal, throttle opening signal, and rotational speed signal as the main input signals.

3. Rail pressure sensor
Common rail pressure is a very important parameter in the common rail system of diesel engines. The real-time change of common rail pressure is related to the amount of fuel injected by the injector. The common rail pressure can measure the pressure in the rail pressure in real time, and the rail pressure under each working condition is different.
For example, the rail pressure at idle speed is 30-40 bar, and the maximum oil pressure at acceleration can reach over 150 bar. The engine electronic control unit compares the pressure measured by the fuel rail pressure sensor with the theoretical pressure value, and regulates the pressure through the fuel metering proportional valve of the high-pressure oil pump.

4. Automobile air conditioning pressure switch
The pressure switch for automotive air conditioning is a pressure protection device set for the normal operation of the refrigeration system, including a high pressure switch and a low pressure switch.
High pressure switch: when the refrigeration system does not work properly or the refrigerant is added too much, the pressure in the air conditioning pipe will be too high, and the high pressure of the system will cause the condenser and high-pressure pipe to burst, the compressor exhaust valve and the electromagnetic clutch to be damaged, etc. When the system pressure reaches the upper limit, the high pressure switch will cut off the working circuit of the electromagnetic clutch, stop the compressor, and at the same time make the cooling fan of the condenser run at a high speed, reducing the pressure and temperature of the condenser. High pressure switches are typically installed at the inlet of the storage drying tank or condenser.
Low pressure switch: The low pressure switch is installed on the liquid storage and drying tank through a threaded connection, and its function is to sense the pressure on the high pressure side. When the pressure of the refrigerant discharged from the compressor is lower than 0.4 MPa or the temperature is lower (lower than 10 degrees), the low pressure switch will disconnect the circuit of the electromagnetic clutch to reduce fuel consumption. The role of energy conservation.

In addition to the several automotive pressure sensors listed above, there are many sensors used in other systems, such as collision systems, electronic detection systems, etc. Their main function is basically to convert pressure into a voltage signal and output it to the control unit ECU.