1. Oxygen sensor: When the oxygen sensor fails, the ECU cannot obtain this information and does not know whether the amount of gasoline injected is correct. An inappropriate oil-gas-air-fuel ratio will cause the engine power to decrease and increase emissions pollution. ;

2. Wheel speed sensor: It mainly collects the speed of the car to determine whether there are signs of skidding. Therefore, there is a sensor that specifically collects the wheel speed of the car to complete this work. It is generally installed On the hub of each wheel, once the sensor is damaged, the ABS will fail;

3. Water temperature sensor: When the water temperature sensor fails, the temperature signal when the cold car is started is often the same as when the car is hot. The ECU cannot get the correct signal and can only supply the engine with a thin mixture, so it is difficult to start when the engine is cold, and it will also be accompanied by unstable idling operation and insufficient acceleration power;

4. Electronics Accelerator pedal position sensor: When the sensor fails, the ECU cannot measure the accelerator position signal and cannot obtain the correct position of the accelerator pedal, so the engine will be unable to accelerate or even be unable to accelerate;

5. Intake pressure sensor: As the name suggests, the intake pressure sensor senses a series of resistance and pressure changes with the engine's different speed loads, and converts them into voltage signals for the ECU to correct the fuel injection amount and ignition timing angle. It is usually installed next to the throttle. If it fails, it will cause problems such as difficulty in ignition, unstable idling, and weak acceleration. Working principle of crankshaft position sensor:

There are three main types: magnetoelectric induction type, Hall effect type and photoelectric type. The working principles of the three types are:

1. Magnetoelectric induction type:

The magnetoelectric induction speed sensor and crankshaft position sensor are installed on the distributor in upper and lower layers. Inside. The sensor consists of a permanent magnet induction detection coil and a rotor (timing rotor and speed rotor), which rotates with the distributor shaft. The timing rotor has one, two or four teeth, and the speed rotor has 24 teeth. The permanent magnet induction detection coil is fixed on the distributor body. If the speed sensor signal and crankshaft position sensor signal are known, as well as the working sequence of each cylinder, the crankshaft position of each cylinder can be known. The rotor signal discs of magneto-inductive speed sensors and crankshaft position sensors can also be mounted on the crankshaft or camshaft.

2. Hall effect type:

The Hall effect speed sensor and crankshaft position sensor are signal generators that utilize the Hall effect. The Hall signal generator is installed in the distributor, coaxial with the distributor head, and is integrally fixed on the distributor plate by a packaged Hall chip and a permanent magnet. The number of notches on the trigger impeller is the same as the number of engine cylinders. When the blades on the trigger impeller enter between the permanent magnet and the Hall element, the magnetic field of the Hall trigger is bypassed by the blades. At this time, no Hall voltage is generated and the sensor has no output signal; when the notch on the trigger impeller enters the permanent magnet When between the sensor and the Hall element, the magnetic lines of force enter the Hall element, the Hall voltage increases, and the sensor outputs a voltage signal.

3. Photoelectric type:

The photoelectric crankshaft position sensor is generally installed in the distributor and consists of a signal generator and a signal plate with a light hole. The signal plate rotates photoelectrically with the distributor shaft. There are 360 ??photolithographic slits in the outer ring of the signal plate, which generates a signal of 1° crankshaft angle. Slightly inside, there are 6 light holes evenly spaced at 60° intervals, generating a crankshaft angle of 120°. ° signal, one of which is wider, is used to generate a signal relative to the top dead center of cylinder 1. The signal generator is installed on the distributor housing and consists of two light-emitting diodes, two photosensitive diodes and a circuit. The light-emitting diode is facing the photodiode. The signal disk is located between the light-emitting diode and the photosensitive diode. Since there are light holes on the signal disk, light transmission and light shielding alternately change. When the light beam of the light-emitting diode shines on the photosensitive diode, the photosensitive diode generates a voltage; when the light beam of the light-emitting diode is blocked, the voltage of the photosensitive diode is 0. After these voltage signals are shaped and amplified by the circuit part, the signals at crankshaft angles of 1° and 120° are sent to the electronic control unit. The electronic control unit calculates the engine speed and crankshaft position based on these signals.

The crankshaft position sensor is usually installed in the distributor and is one of the most important sensors in the control system. Its functions include: detecting the engine speed, so it is also called a speed sensor; detecting the top dead center position of the piston, so it is also called a top dead center sensor, including detecting the top dead center signal of each cylinder for controlling ignition and controlling the sequential injection. The top dead center signal of the first cylinder of oil.