R & D

On the application of sensors in the automotive industry

Core tip: The sensor is a detection device that converts input variables into signals that can be measured. It is the "sensory organ" of the photoelectric system and is the primary link for automatic detection and automatic control. The sensor market is huge. As far as the world is concerned, the fastest-growing sensor market is still the automotive market, and the process control market occupies the second place. The communication market is promising.

The key to the level of modern high-end cars' electronic control system is the number and level of sensors used. At present, about tens to hundreds of sensors are installed on an ordinary family car, while the number of sensors on luxury cars can be as much as more than 200. Only, there are usually more than 30 species, and more than 100 species.

Sensors used in electronically controlled fuel injection engines

1. Intake pressure sensor: It reflects the change of the absolute pressure in the intake manifold and provides the ECU (engine electronic control unit) with a reference signal to calculate the fuel injection duration; the domestic Audi 100 model car (V6 engine), Santana 2000 This type of pressure sensor is used in small cars, Beijing Cherokee (25L engine), Toyota Crown 3.0 cars, etc. At present, the semiconductor varistor type intake pressure sensor is widely used.

2. Air flow sensor: measures the amount of air sucked by the engine and provides it to the electronic control unit (ECU) as a reference signal for fuel injection time; according to different measurement principles, it can be divided into rotary vane air flow sensors (Toyota PREVIA station wagons) , Carmen vortex air flow sensor (Toyota Lexus LS400 sedan), hot wire type air flow sensor (Nissan Maxima VG30E engine and domestic Tianjin Sanfeng passenger car TJ6481AQ4 installed Volvo B230F engine) and hot film type air flow sensor four types. The first two are volume flow type, the latter two are mass flow type. At present, two main types of hot-wire air flow sensors and hot-film air flow sensors are used.

3. Throttle position sensor: measures the opening angle of the throttle valve and provides it to the ECU as a reference signal for fuel cut, fuel/air ratio control, and ignition advance angle correction; it has three types: switch contact throttle position sensor (Santa) 2000 car and Tianjin Sanfeng bus), linear variable resistance throttle position sensor (Beijing Cherokee), integrated throttle position sensor (domestic Audi 100 V6 engine).

4. Crankshaft angle sensor: also called crankshaft position sensor, used to detect crankshaft and engine speed, and provided to ECU as a reference signal to determine ignition timing and working order; there are three types: electromagnetic pulse crankshaft position sensor, Hall effect type Crankshaft position sensor (Santana 2000 car and Beijing Cherokee), photoelectric effect crankshaft position sensor. Different types of crankshaft position sensors have different control methods and control accuracy. The crankshaft position sensor is generally installed on the side of the crankshaft pulley or sprocket, some are installed at the front end of the camshaft, and some are installed at the distributor (Santana 2000 car).

5. Oxygen sensor: detects the oxygen concentration in the exhaust gas and provides it to the ECU as a reference signal to control the fuel/air ratio near the optimal value (theoretical value);

6. Intake air temperature sensor: detects the intake air temperature and provides it to the ECU as a basis for calculating the air density;

7. Water temperature sensor: detects the temperature of the coolant and provides engine temperature information to the ECU;

8. Deflagration sensor: It is installed on the cylinder to specifically detect the deflagration status of the engine, and is provided to the ECU to adjust the ignition advance angle according to the signal.

9. Knock sensor: It is installed on the cylinder of the engine to monitor the knock of the engine at any time. At present, there are two types of resonance type and non-resonance type.

Sensors used in chassis control

1. Transmission: There are vehicle speed sensor, temperature sensor, shaft speed sensor, pressure sensor, etc., and the steering gear has rotation angle sensor, torque sensor, hydraulic sensor;

2. Suspension: vehicle speed sensor, acceleration sensor, body height sensor, roll angle sensor, rotation angle sensor, etc .;

3. ABS: There is a wheel speed sensor.

The sensors of the body are closely related to safety performance.

There are mainly airbag sensors, side anti-collision sensors, ranging sensors, and so on.

Sensors for lighting and electrical systems

There are mainly light detection sensors, raindrop volume sensors, air conditioning temperature sensors, seat position sensors, etc.

In addition, car chassis control, vehicle positioning/location, object detection, visual enhancement, automotive environment heating, ventilation, air conditioning, and engine and transmission control, driver seat automatic adjustment, driver seat automatic adjustment, electronically controlled fuel injection, exhaust emissions, Electronic anti-lock braking system, headlight brightness control, etc. all rely on the sensor information to reflect.