Vehicle sensors are input devices for automotive computer system. They transfer the information of various working conditions during vehicle operation such as vehicle speed, temperature of various media, engine operation condition into electrical signal to send to computers to keep the the engine in optimum working condition.
With the automotive getting more and more intelligent, transformer many functions in the vehicle are manipulated by computers. There are many sensors on one vehicle, they can be divided into oxygen sensor, air flow sensor, speed sensor, nitrogen oxide sensor, temperature sensor and pressure sensor according to their function. Once one of the sensor is in failure, the corresponding device will not work or work abnormally. Then, let’s introduce some main sensors and the function of them.
The flow sensor is mainly used for the measurement of engine air flow and fuel flow. The measurement of air flow is used by the engine control electric track system to determine combustion conditions, control air-fuel ratio, start, ignition, etc. There are four types of air flow sensors: rotary vane (blade type), carmen vortex type, hot wire type and hot film type. The structure of air flowmeter of rotary vane type is simple and the measurement accuracy is low. The measured air flow needs temperature compensation. Carmen vortex type air flowmeter has no movable parts, which has sensitive reflection and high precision. It also needs temperature thermometer compensation.
The hot wire air flowmeter has high measurement accuracy and does not need temperature compensation, but it is easy to be affected by gas pulsation and wire breakage. The measuring principle of hot film air flowmeter is the same as that of hot wire air flowmeter, but the volume is small, suitable for mass production and low cost. We all know that there are USB charging in many cars, we can charge our phone by mobile wireless charger.
Function of flow sensor
The speed of the impeller is proportional to the flow, and the number of revolutions of the impeller is proportional to the total flow. The output of the turbine flowmeter is a frequency modulated signal, which not only improves the anti-interference of the detection circuit, but also simplifies the flow detection system. Its range ratio can reach 10:1 and its accuracy is within ± 0.2%. The time constant of turbine flowmeter with small inertia and small size can reach 0.01 seconds.
The pressure sensor is mainly used to detect cylinder negative pressure, atmospheric pressure, boost ratio of turbine engine, cylinder internal pressure, oil pressure, etc. Suction negative pressure sensor is mainly used to detect suction pressure, negative pressure and oil pressure. Automotive pressure sensors are widely used in capacitive, piezoresistive, differential transformer (LVDT) and surface elastic wave (SAW).
Functions of pressure sensor
Pressure sensor is usually composed of pressure sensitive element and signal processing optical network unit. According to different test pressure types, pressure sensors can be divided into gauge pressure sensor, differential pressure sensor and absolute pressure sensor. Pressure sensor is the most commonly used sensor in industrial practice. It is widely used in various industrial automatic control environments, including water conservancy and hydropower, railway transportation, intelligent building, production automatic control, aerospace, military industry, petrochemical, oil well, electric power, ship, machine tool, pipeline and many other industries
Knock sensor is used to detect engine vibration, control and avoid engine knock by adjusting ignition advance angle. Knock can be detected by detecting cylinder pressure, engine block vibration and combustion noise. Knock sensors are magnetostrictive and piezoelectric. The service temperature of magnetostrictive knock sensor is – 40 ℃ ~ 125 ℃, and the frequency range is 5 ~ 10kHz; At the center frequency of 5.417khz, the sensitivity of piezoelectric knock sensor can reach 200mV / g, and has good linearity in the amplitude range of 0.1g ~ 10g.
Function of knock sensor
It is used to measure the engine jitter and adjust the ignition advance angle when the engine produces knock. Generally, they are piezoelectric ceramics. When the engine shakes, the ceramics inside are squeezed to produce an electrical signal. Because the electrical signal is very weak, the connecting wire of general knock sensors is wrapped with shielded wire.
Today’s vehicles use many different sensing devices, with each sensor serving a useful purpose.The automobile of future will likely to have several hundred sensors transmitting information to powerful ECUs and making the cars more efficient and safer to drive. Our sensors are special for different types of cars, such as we have VW Oxygen Sensor. Sensors are very important for an vehicle. For more information about automatic sensors, pls turn to YASEN.
Post time: Nov-24-2021