The sensors on the car are very important, these 8 sensors need to be known

The sensors on the car are very important, these 8 sensors need to be known

(Source: Chen Xiansen Kanche)

Many car owners and friends are curious about how the vehicle information displayed by our vehicle system is realized, such as the water temperature on the instrument, the vehicle speed, and the rotation speed, etc., in fact, these are all realized by the sensors on the body. The sensors on the car body are diverse, each of which bears its own important responsibilities, so we cannot say who is important and who is not. Next, I will share with you the car sensors I know.

1. ABS sensor. Speaking of the sensors on the car body, my first reaction is the ABS sensor, because other sensors are mainly used to monitor the “health condition” of the vehicle, while the ABS sensor is just the opposite, directly related to the life safety of the drivers and passengers.

Working principle: ABS sensor is an important part of the ABS system of a vehicle. It mainly monitors the speed of each tire in real-time through the ABS sensor distributed on 4 wheels, so as to judge the lock state of the tire. When the tire locks up, the ABS system will start to close the ground spike that outputs the braking force on the locked tire. If the tire is still locked at this time, the ABS system will open the normally closed output solenoid valve, then the tires The above braking force will quickly drop due to the pipeline of the brake fluid storage tank, thereby avoiding the situation of the tires being completely locked.

The sensors on the car are very important, these 8 sensors need to be known

From the perspective of braking, when the slip rate of the vehicle is maintained at 20%, the braking effect of the vehicle is the best, and the braking power is maintained at the best state. In addition, the most widely used ABS sensor is the indirect tire pressure monitoring system. For example, the one provided by Volkswagen can detect tire leaks, but cannot accurately determine which tire is damaged. The main principle is that when the tire is injured and leaks, the tire becomes flat. , The circumference becomes shorter, so the speed is lower than other normal tires, and the tire pressure monitoring system can determine the faulty tire.

Troubleshooting: When the ABS sensor is damaged, the most direct manifestation is the ABS light and traction control light on the vehicle instrument. At this time, directly reading the fault with the decoder can accurately determine the faulty sensor, but in many cases the sensor fault is due to the sensor The top induction coil was wrapped in sand or dust. I have encountered such a situation myself. After the ABS sensor was removed and cleaned, the fault was completely resolved.

2. Air flow meter (air flow sensor): The air flow sensor is generally located near the air filter of the vehicle, and is mainly used to detect the air intake volume per unit time of the vehicle, so as to maintain the ratio of air and gas required when the vehicle starts. In the best state of 14.7:1, when the air flow meter fails, the vehicle will experience increased fuel consumption, excessive exhaust, weak acceleration, and stalling.

3. The water temperature sensor, which plays an important role in the engine system, is directly related to the important parameter of the engine-water temperature. When the water temperature is detected to exceed 90 degrees, most vehicle ECU systems will control the operation of the vehicle’s electronic fan for heat dissipation. When the temperature is too low, it will increase the engine temperature by increasing the speed of the vehicle. Fault status: The water temperature light on the meter cannot be displayed normally, the idling speed of the cold car is unstable, and the fuel consumption of the car increases.

4. Oxygen sensor. The main function of the oxygen sensor is to keep the air-fuel ratio of the vehicle at the best theoretical value of 14.7 as much as possible. By monitoring the ratio of gasoline atomization and air, the oxygen content in the exhaust gas produced by the vehicle engine can be judged. The oxygen content is transmitted to the vehicle’s ECU system as a voltage signal, so that the engine can achieve closed-loop control targeting excess air, ensuring the maximum conversion of hydrocarbons, carbon monoxide, and nitrogen oxides in the exhaust.

5. Throttle position sensor is mainly used to detect the throttle opening to control the fuel injection when the vehicle is accelerating.

6. The crankshaft position sensor is mainly used to detect the position of the crankshaft and the speed of the engine, so as to judge the best fuel injection point and ignition position when the vehicle engine is working.

7. Odometer sensor. The odometer sensor is mainly located on the differential or half shaft of the vehicle, so as to sense the speed of the vehicle and achieve the function of recording mileage. Because the angular velocity of the half shaft and the wheels of the vehicle are the same, you know the direct situation of the tires. Next, the vehicle ECU bureau can directly calculate the mileage of the vehicle.

8. Oil pressure sensor. The oil pressure sensor is mainly installed on the main oil passage of the engine. When the engine is working, the oil pressure sensor detects the oil pressure and sends the oil pressure to the ECU as an electrical signal. The ECU will compare the stored Normal oil pressure value. When the alarm voltage is lower than the normal value, the ECU will light up the indicator light on the instrument through the alarm line.

In fact, there are many types of sensors on the car, not just these 8 sensors, each of them has its own meaning, and they have different functions. Only when they cooperate with each other can the vehicle drive normally and stably.
(Editor in charge: fqj)

Author: Mara.M