In the 1960 s, there were only oil pressure sensors, oil quantity sensors and water temperature sensors on cars, which were connected with instruments or indicator lights. In the 1970s, in order to control emissions, some sensors were added to help control the power system of automobiles, because the catalytic converters, electronic ignition and fuel injection devices that appeared in the same period all needed these sensors to maintain a certain air-fuel ratio to control emissions. In 1980s, anti-lock devices and airbags improved automobile safety. Today, sensors are everywhere. In the power system, there are sensors to measure the temperature and pressure of various fluids (such as intake temperature, airway pressure, cooling water temperature and fuel injection pressure, etc.). ); Sensors are used to determine the speed and position of each part (such as vehicle speed, throttle opening, angle and speed of camshaft, crankshaft, transmission, EGR position, etc.). ); There are also sensors for measuring engine load, knock, misfire and oxygen content in exhaust gas; A sensor for determining the seat position; Sensors for measuring wheel speed, road height difference and tire pressure in anti-lock braking system and suspension control device; To protect the airbag of the front passenger, not only more collision sensors and acceleration sensors are needed, but also sensors such as the position and weight of the passenger are needed to ensure its timely and accurate work. Facing the manufacturer's side volume, overhead airbag and more exquisite side airbag, sensors should be added. As researchers use anti-collision sensors (ranging radar or other ranging sensors) to judge and control the lateral acceleration, the instantaneous speed of each wheel and the required torque, the braking system has become an integral part of the vehicle stability control system. In a word, the old oil pressure sensor and water temperature sensor are independent of each other, and some of them are actually equivalent to switches because they have clear maximum or minimum values. With the development of electronic and digital sensors, their output values will be more relevant. To this end, manufacturers are developing and producing better sensors.