The technological advancement of cars is extraordinary, and we are entering a natural world where newly sold cars are equipped with automatic control systems. Various sensors installed on the engine and the body control the automatic control of the car. However, due to the body structure, many people may not know which sensor to use. Let's understand the functions and types of various sensors used in automobile automatic control together, and explain the main types of sensors used in automobile engine control, safety performance and automatic driving.
Types and functions of automotive sensors
Automobile sensors have the function of measuring and detecting information such as the interior and exterior of the automobile, which are essential for all functions of the automobile. Broadly speaking, there are powertrain control systems, vehicle control systems, body control systems, and information and communication system sensors. These sensors are used for the following functions. Powertrain control system, exhaust and energy saving (fuel consumption) related systems, engine control and other vehicle control systems, suspension control, anti-lock braking and other body control systems, airbags, front and rear monitoring, anti-glare lighting and other information communication systems, GPS, automobiles Navigation system, gyroscope sensor, acceleration sensor, etc.
The main types of sensors used to control car engines
The engine is where the most sensors are used in a car. Typical sensors used for engine control are as follows.
Pressure sensor Pressure sensor is indispensable for engine control, it has many uses and functions. The "intake pressure sensor" that properly controls the fuel injection device to improve fuel efficiency, the "exhaust pressure sensor" that detects the clogging of the diesel exhaust filter, the "combustion pressure sensor" that measures the combustion pressure in the cylinder, etc. Except for the engine , Pressure sensors are also used to control various parts, such as brakes, suspensions, tire pressure and air conditioning compressors.
Emission sensor The exhaust gas sensor is a sensor used to purify the exhaust gas emitted by a gasoline engine. Exhaust gas containing substances harmful to the environment and human body must be converted into safe chemical substances through purification catalysts. The sensors used to purify exhaust gas are an "air-fuel ratio sensor" that detects the oxygen concentration in the exhaust gas, and an "O2 sensor (oxygen sensor)" that measures the oxygen concentration in the exhaust gas and adjusts the fuel injection amount. In addition, in the case of a diesel engine, a “NOx sensor” for measuring the concentration of NOx gas and a “PM sensor” for measuring PM (particulate matter) in exhaust gas are installed.
Crankshaft Angle Sensor The crankshaft angle sensor detects the rotation angle and reference position of the crankshaft in the engine and the engine speed. It plays an important role in controlling the fuel injection and ignition timing in the gasoline electronic fuel injection system.
Main sensor types used for car safety performance and autonomous driving
The following sensors are used for safety features such as automatic braking and automatic driving.
Millimeter-wave radar Millimeter-wave radar can emit short-wave radio waves of about 10 millimeters and measure the distance of objects from 2 to 200 meters away. Since it can detect pedestrians and obstacles, it can be used for anti-collision brakes and ACC (Adaptive Cruise Control) to maintain the distance from the vehicle in front. The advantage of millimeter wave radar is that it is not affected by the weather, but it is larger and more expensive.
Infrared radar is like millimeter wave radar. Infrared radar detects the distance of an object through radio waves. Although the measurable distance is as short as about 20 meters, compared with millimeter wave radar, it has the advantages of lower cost and more compact size.
The role of the camera on-board camera is to identify pedestrians, road signs, traffic lights, etc. The stereo camera method is a stereo camera method in which humans use two cameras like eyes and measure the distance from the difference in appearance. This method is used in advanced driving assistance systems such as automatic braking and ACC.
However, the disadvantage of the camera is that it cannot be used normally under severe weather such as direct sunlight, backlighting, heavy rain and heavy snow.