Crankshaft sensor classification
There are three main types of crankshaft sensors: magnetoelectric induction, Hall effect and photoelectric.
1, magnetic induction type:
The magnetoelectric induction speed sensor and the crankshaft position sensor are installed in the distributor in upper and lower 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. The timing rotor has one, two or four teeth and other forms, and the rotating rotor has 24 teeth. The permanent magnet induction detecting coil is fixed on the distributor body. If the speed sensor signal and the crankshaft position sensor signal are known, as well as the operating sequence of each cylinder, the crankshaft position of each cylinder can be known. The rotor signal disc of the magnetoelectric induction speed sensor and the crank position sensor can also be mounted on a crankshaft or camshaft.
2, Hall effect type:
The Hall effect speed sensor and the crank position sensor are signal generators that utilize the Hall effect. The Hall signal generator is installed in the distributor, coaxial with the splitter head, and is integrally fixed on the distributor board by the packaged Hall chip and the permanent magnet. The number of notches on the trigger impeller is the same as the number of cylinders in the engine. When the blade on the impeller is triggered to enter between the permanent magnet and the Hall element, the magnetic field of the Hall trigger is bypassed by the blade, and no Hall voltage is generated at this time, and the sensor has no output signal; when the notch portion on the impeller is triggered to enter the permanent magnet When it is between the Hall element and the Hall element, the magnetic field line enters the Hall element, the Hall voltage rises, and the sensor outputs a voltage signal.
3, photoelectric type:
The photoelectric crank position sensor is generally installed in the distributor, and is composed of a signal generator and a signal plate with a light hole. The signal disc rotates together with the distributor shaft. There are 360 lithography gaps on the outer ring of the signal disc, which generates a signal with a crank angle of 1 °. There are 6 optical holes with a uniform spacing of 60 ° inside, which produces a crank angle of 120 °. The signal, one of which is wider, is used to generate a signal relative to the top dead center of the cylinder. The signal generator is mounted on the distributor housing and consists of two light-emitting diodes, two photodiodes and a circuit. The LED is facing the photodiode. The signal disc is located between the light-emitting diode and the photodiode. Due to the light hole on the signal disc, alternating light transmission and shading are generated. When the light beam of the light emitting diode is directed to the photodiode, the photodiode generates a voltage; when the light emitting diode beam is blocked, the photodiode voltage is zero. These voltage signals are shaped and amplified by the circuit portion to deliver signals to the electronic control unit at crank angles of 1 ° and 120 °, and the electronic control unit calculates the engine speed and crankshaft position based on these signals.