With the wide application of automotive electronic control system, people pay more and more attention to the temperature and humidity sensors in the automotive field. Along with the increasing automobile sensor market demand, miniaturized, multifunctional, integrated and intelligent sensors will gradually replace traditional sensors and become the mainstream of automotive sensors. Miniaturized temperature and humidity modules have been widely used in automotive electronic clocks.
The sensor is the main control part of the automotive electronic unit, which provides the engine’s working condition information to the electronic control unit (ECO) of the engine for ECU to accurately control the engine’s working condition so as to improve the engine’s power performance, reduce fuel consumption and reduce exhaust emission fault detection.Temperature sensors can prevent auto spontaneous combustion accident and make energy saving and emission reduction. To some extent, the competition for cars is the competition for sensors. There are many kinds of temperature sensors in cars. Some are used to detect the inlet temperature of the engine, some used to detect the coolant temperature, the others used to detect for oil or air conditioning inside the car, and so on. Most of these temperature sensors are thermistors with negative temperature coefficient, where the higher the temperature in measuring point is, the lower the resistance value of the sensor and the lower the output voltage signa.
1. Air Intake Temperature Sensor
In addition to the Carmen scroll air flow sensor, other engines are equipped with air intake temperature sensors.The sensor can be installed in the air flow sensor or in the inlet pressure sensor, or in a certain part of the inlet.The control unit decreases the injection pulse width when the intake temperature of the engine is high, and increases the injection pulse width conversely.
2. Coolant Temperature Sensor
If the terminals of the coolant temperature sensor are 2 pins, one is the input signal line and the other is the output signal line. If the terminals are 4 pins, the 4 pins are input signal line and output signal line controlling unit lap wire and instrument panel lap wire respectively. Coolant temperature sensor is usually installed in the engine rear thermostat or radiator outlet, responsible for injection pulse width, warming up, ignition for advance Angle, automatic transmission torque converter lock and controlling overspeed block as well as air conditioning .The main functions are as follows: Responsible for controlling the concentration of mixed steam, the lower the temperature, the thicker the mixed steam. Responsible for the control of engine speed when the engine is warm, the speed below 40℃ is 1500r/min, 40~70℃ is 1100r/min. Responsible for the control of radiator fan, low speed rotation starts from above 85℃, high speed rotation starts from 105℃. Responsible for controlling the automatic transmission, the torque converter above 56℃ enters the locking condition, and the transmission is allowed to enter the overspeed gear at 70℃. Responsible for the control of air conditioning, the air conditioning will exit control at 120℃.
3. Transmission oil temperature sensor
Automatic transmission oil temperature sensor installed in the control valve is mainly for high temperature control.When the oil temperature of the transmission is higher than 150℃, the torque converter immediately enters the locking condition. If the oil temperature of the transmission still does not drop after 30s, the torque converter will release the locking condition and the transmission will exit the overspeed gear. If the oil temperature sensor shortens itself or the wire harness, the data flow will show that the oil temperature of the transmission is higher than 150℃. Therefore, after the oil temperature sensor shortens itself or the wire harness, the torque converter will not enter the locking condition.
4. Temperature Sensor on the Air Compressor
The air suspension is equipped with a temperature sensor on the nitrogen air compressor. When the compressor temperature reaches 130℃, the work of the compressor is temporarily interrupted to prevent excessive temperature from ablating.Once the air pump ablation, the body height always stays at the lowest position, no longer rising.
5. Air Conditioning Temperature Sensor
Automatic air conditioning system temperature sensors include engine coolant temperature sensors, car temperature sensors, environmental temperature sensors, evaporator temperature sensors, solar radiation sensors and refrigerant temperature control switches. Based on the sensor signal, the control unit calculates the temperature needed for blowing air into the cabin, selects the desired air quantity, and then controls the entrance air mixed, the water valve, in and out of the port transfer board and so on. The control unit automatically adjusts the temperature of the cabin within the scope of the pilot to the best and automatically control the opening and closing of air conditioning.The temperature sensor plays an important role in the electronic control system of automobile.Temperature sensor is a kind of high-tech products, mainly focusing on electronic information research, directly subject to the control of ECU and direct transmitting all kinds of automotive temperature, which is the highly skilled product with, complex structure and strong performance price. It is necessary for people to carry on the summary to the automobile temperature and the input and the output so as to guarantee the automobile safe driving. The working state of temperature sensor directly affects the driving of cars and its performance is an important standard to evaluate the safety price of automobile.