What are the detection contents of the crankshaft position sensor?

The crankshaft position sensor, also known as the engine speed sensor, is one of the most important sensors in the centralized engine control system and is used for detectionThe signals of the piston top dead center and the angle of rotation of the crankshaft are measured and input into the engine ECUIt is used to control the ignition time and injection timing, and it is also a signal source for measuring engine speed.

Note: Although there are many types of vehicles, the structure is similar. This should be said to be the credit of standardization, but also the need for large-scale production lines.

With the development of society, the progress of science and technology and the change of demand, the shape of railway vehicles has begun to change, especially the passenger car is no longer the same old face. However, their basic structure has not changed significantly, but the specific parts have a more scientific and advanced structural design.

Generally speaking, the basic structure of the vehicle is composed of five parts: the car body, the undercarriage, the running part, the coupler buffer device and the braking device.

The body is the part of the vehicle that is used to load goods or passengers, and is the basis for the installation and connection of other components of the vehicle. The body of the early vehicles was mainly made of wood, supplemented by steel plates, bow rods, etc. In modern times, the car body is mainly steel structure or light metal structure.

The role of the crankshaft position sensor is to detect the engine angle, i.e. the position of the crankshaft. If the crankshaft position sensor is damaged, the engine control unit cannot receive a reference signal at start-up, and the ignition coil does not generate high voltage. After 2s of turning on the ignition switch, if the engine is not started, the engine control unit will cut off the control voltage to the fuel pump relay and stop supplying power to the fuel pump and ignition coil, resulting in the vehicle being unable to start.

There are generally two types of crankshaft position sensors: electromagnetic inductive sensors and Hall sensors.

There is a coil inside the electromagnetic induction sensor, which can measure its resistance value, two wires, will use a multimeter to measure the frequency of the two wires, check the gear of the signal generator, the Hall sensor is three wires, there is a positive wire, a negative wire, a signal line leads to the engine computer, you use the decoder to detect the signal of the position sensor, that is, to see the data flow.

How the crankshaft position sensor works:

There are three main types: magnetoelectric induction, Hall effect, and photoelectric. The three types work on the following principles:

1. Magnetoelectric induction:

The magnetoelectric inductive speed sensor and the crankshaft position sensor are installed in the distributor in two layers. The sensor consists of a permanent magnet induction detection coil and a rotor (timing rotor and speed rotor) that rotates with the distributor shaft. Timing rotor has.

One, two, or four teeth, etc., the speed rotor is 24 teeth. The permanent magnet induction detection coil is fixed on the distributor body. If the speed sensor signal and the crankshaft position sensor signal are known, as well as the working sequence of each cylinder, the crankshaft position of each cylinder can be known.

Rotor signal panels for magnetoelectric inductive speed sensors and crankshaft position sensors can also be mounted on crankshafts or camshafts.

2. Hall effect:

Hall-effect speed sensors and crankshaft position sensors are signal generators that utilize the Hall effect. The Hall signal generator is installed in the distributor, coaxial with the distributor head, and is fixed on the distributor panel by the encapsulated 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 blade on the trigger impeller enters between the permanent magnet and the Hall element, the magnetic field of the Hall trigger is bypassed by the blade, and the Hall voltage is not generated, and the sensor has no output signal; When the notched part on the trigger impeller enters between the permanent magnet and the Hall element, the magnetic field lines enter the Hall element, the Hall voltage rises, and the sensor outputs a voltage signal.

3. Photoelectric type:

Photoelectric crankshaft position sensors are generally installed in distributors and consist of a signal generator and a signal disc with light holes. The signal panel rotates together with the distributor shaft photoelectric type, and there are 360 lithography gaps in the outer ring of the signal panel, which produces a signal with a crankshaft rotation angle of 1 °; Slightly inward, there are 6 orifices evenly spaced 60 ° apart, generating a signal of a 120° angle of rotation of the crankshaft, one of which is wider to generate a signal relative to the top dead center of the 1st cylinder. The signal generator is mounted on a distributor housing and consists of two light-emitting diodes, two photodiodes and a circuit.

The light-emitting diode is facing the photodiode. The signal disk is located between the light-emitting diode and the photodiode, and because there is a light hole on the signal disk, the phenomenon of alternating light transmission and shading occurs. When the beam of the light-emitting diode hits the photodiode, the photodiode generates a voltage; When the LED beam is blocked, the photodiode voltage is 0.

These voltage signals are amplified by the partial shaping of the circuit and are transmitted to the electronic control unit (ECU) at 1° and 120° crankshaft rotation angles, which calculates the engine speed and crankshaft position based on these signals.

Crankshaft position sensors are usually installed in distributors and are one of the most important sensors in control systems. Its functions are: detecting engine speed, so it is also called speed sensor; Detecting the position of the piston top dead center, so it is also called an top dead center sensor, which includes the detection of the top dead center signal of each cylinder used to control the ignition, and the top dead center signal of the first cylinder used to control the sequential fuel injection.

The measurement method of the crankshaft position sensor is as follows: 1. The magnetoelectric type can be tested with a resistance meter, and the resistance value is generally between several hundred and more than a thousand ohms; 2. The engine can be started to measure its voltage, and the voltage should increase with the increase of engine speed. Here's a little more about the crankshaft position sensor

1. Function: The function of the crankshaft position sensing device is to determine the position of the crankshaft, that is, the angle of the crankshaft and the engine speed, which usually works together with the camshaft position sensor, that is, to determine the basic ignition time. 2. Importance:

The crankshaft position sensor is usually installed at the front end of the crankshaft, near the large flywheel or in the middle of the crankshaft, and is one of the most important sensors in the control system.

Crankshaft position sensor test method: unplug its connector, use a multimeter to measure the resistance between the upper terminals of the sensor, should comply with the attached table, otherwise replace the sensor. Pull out the wire connector of the crankshaft position sensor.

When the engine is rotating, there should be pulse signal output between G1, G2 and G terminals. If there is no pulse signal output, the sensor needs to be replaced.

Inspection of crankshaft position and angle sensors. Use the multimeter DC voltage block to measure the power supply voltage of the crankshaft position and angle sensor, the normal value is 12V, and use the multimeter DC voltage block to measure the output signal voltage of the sensor in the starting state. The voltage value of the crankshaft position signal should be, and the voltage value of the crankshaft angle signal should be 2 3V

Measure the output voltage of the Hall sensor. Turn off the ignition switch, open the distributor cover, quietly pull out the central high-voltage line on the distributor cover and ground it, pull out the rubber sleeve on the ignition connection plug, but the connecting plug is still plugged in, connect the two probes of the voltmeter to the number terminal, turn on the ignition switch, rotate the motor according to the direction of rotation of the engine, and the reading of the voltmeter should change between 0 7V, and the crankshaft rotates twice, and the voltage changes four times, otherwise it means that the Hall effect generator is faulty and should be replaced.

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Crankshaft position sensor detection method: pull out its wire plug-in, use a multimeter to measure the resistance between the terminals on the sensor, should comply with the provisions of the attached table, otherwise the sensor should be replaced. When the engine is rotated, there should be a pulse signal output between the G1, G2 and G terminals.

If the hand does not have a pulse signal output, the sensor needs to be replaced.

Inspection of crankshaft position and angle sensors. Use the multimeter DC voltage block to measure the power supply voltage of the crankshaft position and angle sensor, and the normal value should be 12V; The output signal voltage of the sensor in the starting state is measured with the DC voltage block of the multimeter, the signal voltage value of the crankshaft position should be 0 8 0 9V, and the signal voltage value of the crankshaft angle should be 2 3V.

Measure the Hall sensor output voltage. Disconnect the ignition switch, open the distributor cover, pull out the distributor cover and put on the high-voltage wire and tie the iron, unplug the rubber sleeve on the ignition connection plug, but the connecting plug is still plugged in, connect the voltmeter to the No. 3 and 6 terminals, turn on the ignition switch, rotate the engine according to the direction of engine rotation, observe that the voltmeter reading should change between 0 7V, dust pants and crankshaft rotate twice, and the voltage changes 4 times, otherwise the Hall effect generator is faulty and should be replaced.

The detection method of the crankshaft position sensor is as follows: 1. The detection of the resistance of the crankshaft position sensor, pull out the trace ridge wire plug, and measure the resistance between the terminals on the sensor with a multimeter, which should comply with the provisions of the attached table, otherwise the sensor should be replaced; 2. For the detection of the output signal, pull out the wire plug of the crankshaft position sensor, when the engine is rotated, there should be a pulse signal output between the terminals, and if there is no pulse signal output, the sensor needs to be replaced; 3. To detect the gap between the sensor coil and the signal rotor, check the air gap between the signal rotor and the sensor coil bulge with a thickness gauge, and the gap is to, if the gap does not meet the requirements, it needs to be adjusted or replaced.

The principle of the crankshaft position sensor is to provide ignition timing (ignition advance angle) and crankshaft position confirmation signals for detecting the piston top dead center, crankshaft angle and engine speed. The function of the key sensor in the crankshaft position section is to determine the position of the crankshaft, i.e. the angle of rotation of the crankshaft and the engine speed. The measurement method of the crankshaft position sensor is as follows:

1.Check that the normal grip gap between the crankshaft position sensor and the pulse wheel (target wheel) should be greater than millimeters, less than millimeters, if the pulse wheel is installed incorrectly, too large or too small may cause signal deviation; 2.Turn off the ignition, disconnect the plug of the crankshaft position sensor, there should be 400 600 between the first and second ends of the measuring sensor.

If it is not within this range, it can be judged that the crankshaft position sensor itself is faulty and the sensor should be replaced. The two signal wires of the crankshaft position hidden rental sensor are insulated from the shielded wires; 3.Turn on the ignition switch and measure the ground voltage of the two signal lines should be, which is the preset voltage of the engine control unit on the signal line.

When starting the starter, if the sensor, signal line, and engine control unit are open or short-circuited, the computer cannot receive the crankshaft position signal, and the engine cannot start. The signal voltage of the crankshaft position sensor should be close.