With the continuous development and application of electronic technology in the automotive field, more and more auto parts began to use electronic control. As the electronic system only rely on electrical signal work, so the car needs to use the sensor to a variety of optical excitation, chemical excitation and mechanical excitation into electrical signals. These sensors are able to operate reliably Sensor in harsh environments of temperature, humidity, shock, vibration and electromagnetic interference, and these extreme operating conditions greatly shorten the service life of the corresponding conventional sensors. We will apply the sensor to a car called a car sensor.
According to the role of the sensor, can be classified as measuring temperature, pressure, flow, location, gas concentration, speed, brightness, dry humidity, distance and other functions of the sensor (the composition of the car drive system), they perform their duties, Sensor failure, the corresponding device work will not work or even work. Therefore, the role of the sensor in the car is very important.
1. Water temperature sensor: its internal is a semiconductor thermistor, the lower the temperature, the greater the resistance; the other the smaller the resistance, installed in the engine block or cylinder head of the water jacket, and direct contact with the cooling water. Thereby achieving the temperature of the engine cooling water. The electronic control unit according to this change measured Suction Control Valve the temperature of the engine cooling water, the lower the temperature, the greater the resistance; the smaller the resistance. The electronic control unit measures the temperature of the engine cooling water according to this change as the correction number of the fuel injection and ignition timing. Simply put that we can understand the speed of the engine through the current temperature of the engine, stop or exercise, or how long the movement time.
2. Air flow sensor: its role is to detect the size of the engine intake air, and the intake air volume information into electrical signal output, and sent to the ECU. We know that the car is driving the ignition device is required to get forward the impulse, therefore, the amount of inflation is the size of the ECU to calculate the ignition time in the ignition device ignition time and fuel injection and ignition time basis. Its role is to allow us to better drive the car to slow down.
3.ABS sensor: in the brake piston next (card brake disc calipers, which is the brake piston), ABS work is to ensure that the brake piston and brake discs are not stuck, to ensure that they are in the sliding friction and static friction edge. Most of the sensor sensor to monitor the speed, abs sensor with the wheel with the rotation of the ring gear, the output of a group Fuel Rail Pressure Sensor of quasi-sinusoidal AC signal, the frequency and amplitude and wheel speed related to the output signal to the ABS electronic control unit (ECU ), To achieve real-time monitoring of wheel speed.
Four. Odometer sensor: the differential or axle above the sensor, to feel the number of turns of rotation, the general use of Hall, photoelectric two ways to detect the signal, the purpose of the use of odometer count can be an effective analysis to determine the car Of the speed and mileage, because the axle and the wheel of the angular velocity is equal to the known tire radius, directly through the process parameters to calculate. In the drive shaft design of the two bearings, greatly reducing the running force, reducing the friction, and enhance the service life; from the original dynamic detection signal to the gear running detection signal; from the original vertical vertical gearbox Changed to chamfer interface gearbox. Odometer sensor plug is generally in the gearbox, and some open the engine cover can be seen, and some to operate in the trench.
V. Position and speed sensor: mainly used to detect the engine crank angle, engine speed, throttle opening, speed detection, vehicle acceleration detection, vehicle deceleration detection, etc., for the ignition time and fuel injection time to provide reference point signal, Provide engine speed signal. At present, the position and speed sensor used in the car are mainly alternator type, magnetoresistive type, Hall effect Temperature Sensor type, reed switch type, optical type, semiconductor magnetic transistor type.
6. Airbag sensor: also known as the collision sensor, according to the use of different, divided into trigger collision sensor and protective collision sensor. Trigger collision is used to detect the acceleration change at the time of collision and pass the collision signal to the airbag computer as the trigger signal of the airbag computer. The protective collision type is in series with the trigger collision type to prevent the airbag from bursting.
7. The protective sensor or safety sensor, its role is to prevent the short-circuit before the collision caused by the air bag open, its signal for the computer to determine whether the collision. When the SRS computer connected to the connector terminal short circuit, due to the role of protective sensors, contacts are not closed, the airbag circuit will always be disconnected, so as to avoid Pressure Sensor airbag explosion. In general, the inertia force or deceleration value required for the action of the protective sensor is greater than the inertia force or deceleration value required for the operation of the front impact sensor. When the protective sensor is operated, the power circuit of the SRS igniter is switched on, So that the airbag detonated.
8. Oil pressure sensor refers to the micro-sensors, actuators and signal processing and control circuits, interface circuits, communications and power in one of the micro-electromechanical systems. Commonly used silicon piezoresistive and silicon capacitive, both are generated on the silicon micro-mechanical electronic sensor. In general, we use the oil pressure sensor to detect the car's oil into the gasoline and how much, and the detection of the signal into our understanding of the signal, remind us how much gasoline, or how far can go, Even to remind the car need to add gasoline.
9. Gas concentration sensor is mainly used to detect vehicle body gas and exhaust emissions. Among them, the most important is the oxygen sensor, which detects the oxygen content of the vehicle exhaust, according to the oxygen concentration in the exhaust air to determine the air-fuel ratio, to the computer control device to send a feedback signal to control the air-fuel ratio converges to the theoretical value. When Speed Sensor the air-fuel ratio becomes high and the oxygen concentration in the exhaust gas increases, the output voltage of the oxygen sensor decreases. When the air-fuel ratio becomes low and the oxygen concentration in the exhaust gas decreases, the output voltage increases. The electronic control unit identifies the abrupt signal and corrects the fuel injection quantity so as to adjust the air-fuel ratio accordingly so that it changes in the vicinity of the ideal air-fuel ratio
10. Oxygen sensor In a gasoline engine that uses a ternary catalytic evolution device, an oxygen sensor is generally arranged in the exhaust pipe to detect the oxygen content in the exhaust gas, thereby indirectly determining the concentration of the mixture entering the cylinder, So as to perform closed-loop control of the actual air-fuel ratio. When the oxygen content of the exhaust gas is too high, indicating that the mixture is too thin, the oxygen sensor that is output an electrical signal to the ECU, let the instructions injector to increase fuel injection; when the exhaust oxygen content is too low, The mixture is too thick and the oxygen sensor immediately passes this information to the ECU to instruct the injector to reduce fuel injection. At present, the oxygen sensor used in the car mainly has two kinds of sensors: the titania oxygen sensor and the zirconia oxygen sensor.
11. The engine coolant temperature sensor is on the coolant expansion tank cover. The temperature sensor resistance and the coolant temperature is proportional to the change, the sensor to the instrument panel to send mediation signal voltage control instrument.
12. The valve position sensor is mounted on the throttle body, which converts the throttle opening into a voltage signal output so that the computer can control the fuel injection quantity. Throttle position sensor has switch output and linear output of two types.
One of the characteristics of modern automotive technology development is to increase the advanced features, and these functions are to rely on electronic control to complete. This makes the electronic content of the car increasing. According to statistics, the current general Throttle Position Sensor car about dozens of sensors, high-class cars have more than 100 sensors, is expected by 2005, the global demand for automotive sensors will reach 1.27 billion. So want to know the car world, or start with the sensor.