The structure and working principle of crankshaft and camshaft position sensors

1 Induction crankshaft and camshaft position sensor.

2 Hall type crankshaft and camshaft position sensor.

When a Hall semiconductor substrate (i.e., a Hall element) with an electric current is placed in a magnetic field perpendicular to the direction of the current, a trace voltage is generated in the direction perpendicular to the current and the magnetic field, which we call Hall voltage. The Hall voltage uh is proportional to the passing current i and the strength b of the applied magnetic field.

where: rh - Hall coefficient;

d - the thickness of the Holji sheet.

Hall sensors have two outstanding advantages: first, the output voltage signal is similar to the square wave signal; Second, the output voltage has nothing to do with the speed of the measured object. Hall-effect sensors differ from electromagnetic sensors in that they require an external power supply.

Some cars, such as Cherokee jeeps, etc., use differential Hall sensors. Differential Hall sensors, also known as dual Hall sensors, work on the same principle as Hall sensors, and the output voltage of the sensor is superimposed by two Hall signals.

3 Photoelectric crankshaft and camshaft position sensor.

Photoelectric sensors are mainly composed of a signal rotor with blades and a signal generator including light-emitting diodes, phototransistors, and amplification shaping circuits.

Photoelectric sensors have the advantages of high indexing accuracy and output digital pulse signals, but they also have the disadvantages of high requirements for the use environment.

The role and principle of the camshaft position sensor.

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Camshaft position sensor is a sensing device, also known as synchronous signal sensor, it is a cylinder discriminating positioning device, input camshaft position signal to ECU, is the main control signal of ignition control.

The Camshaft Position Sensor (CPS) is used to collect the camshaft motion angle signal and input it into the electronic control unit (ECU) to determine the ignition time and fuel injection time. Camshaft position sensor (CPS) is also known as cylinder identification sensor (CIS), in order to distinguish it from crankshaft position sensor (CPS), camshaft position sensor is generally represented by CIS. The function of the camshaft position sensor is to collect the position signal of the valve camshaft and input it into the ECU, so that the ECU can identify the top dead center of cylinder 1 compression, so as to carry out sequential fuel injection control, ignition time control and deflagration control.

In addition, the camshaft position signal is used to identify the first moment of ignition when the engine is started. Because the camshaft position sensor is able to identify which cylinder piston is about to reach the top dead center, it is called a cylinder recognition sensor.

1.The crankshaft position sensor is used to detect the engine speed, the crankshaft position (corner) signal, as well as the stop signal of the first cylinder and the compression stroke per cylinder, which is the main signal to control the injection and ignition time. Like the airflow sensor, it is the primary sensor in the engine's centralized control system.

In the microcomputer-controlled electronic ignition system, the specific ignition time is calculated by using the engine crankshaft angle signal, and the basic ignition advance angle is calculated and read by using the speed signal.

2.Camshaft position sensors, also known as phase sensors and synchronous signal sensors, are used to detect the angular position signal of the camshaft, through which the ECU can determine the top dead center position of the cylinder (e.g

3.The crankshaft camshaft position sensor to a specific position (such as a cylinder top dead center or checkpoint at a certain point of view), input a signal distributed to the ECU camshaft position, discriminate to start checking the piston running at this point in time at the compression stroke or vent, so ECU identification 1 check cylinder piston compressor, therefore suitable sequential injection control, ignition control and knock control. In addition, the camshaft position signal is used to identify the first ignition timing when the engine is started.

Since the camshaft position sensor can identify which piston will reach the top dead center, it is also known as a cylinder sensor.

Crankshaft position sensor (CPS) is also known as engine speed sensor and crankshaft angle sensor. Its function is to collect the crankshaft rotation angle and engine speed signals, and input them into the electronic control unit (ECU) to determine the ignition time and fuel injection time.

Camshaft position sensor (CPS) is also known as cylinder identification sensor (CIS). In order to distinguish it from crankshaft position sensors, camshaft position sensors are generally represented by CIS.

1) Camshaft Functions of Crankshaft Position Sensor The Camshaft Position Sensor (CMPS) is the main control signal for fuel injection control and ignition control, providing the ECU with a reference position for the crankshaft angle (first cylinder compression top dead center) signal. The Crankshaft Position Sensor (CKPS) is used to detect the displacement of the crankshaft angle, provide engine speed signal and crankshaft angle signal to the ECU, and is also the main control signal for fuel injection control and ignition control. Since the air flow meter can only detect the amount of air per unit of time, the ECU must determine the amount of air per cycle of the beam bucket based on the engine speed to achieve precise injection control.

In addition, the ECU can use the crankshaft angle signal to determine the working position of each cylinder, so as to control the optimal injection time and the optimal ignition advance angle. The structure and working principle of the camshaft position sensor and the crankshaft position sensor are basically the same, and they are usually installed together, but the installation position is different for different models. However, they must be installed in a location that has a precise transmission relationship with the crankshaft, such as a crankshaft, camshaft, flywheel or distributor.

2) Camshaft Classification of crankshaft position sensorsCam key balance shaft Crankshaft position sensors can be divided into electromagnetic, Hall and photoelectric types.