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how does an electronic speedometer work
Composition of electronic speedometer:
The electronic speedometer is composed of a speed sensor, a signal processing circuit, a speedometer and an odometer.
How the electronic speedometer works:
The speedometer sensor is installed in the instrument cluster and is driven by the transmission via a flexible shaft. When the car is moving, it generates a signal proportional to the speed. It consists of a reed switch with one or several pairs of contacts and a rotor.
Signal processing:
The signal processing circuit is composed of a monostable trigger circuit, a constant current circuit, a 64 frequency division circuit, a power amplifier circuit and a power regulation circuit. When the car is running, it transforms the pulse signal input by the speed sensor into a current signal, and drives the speedometer to indicate the speed after being amplified; at the same time, it also converts the pulse signal into a pulse signal of a certain frequency through frequency division and power amplification. Thereby driving the shaft of the odometer stepper motor to rotate and record the mileage of the car. The speedometer uses a magnetoelectric ammeter as an indicator. When the car is running at different speeds, the signal processing circuit converts the pulse signal input by the speed sensor into a current signal proportional to the speed, so that the pointer of the ammeter deflects to indicate the corresponding speed.
Odometer:
The odometer consists of a stepping motor, a six-digit decimal counter and an internal transmission gear. When the vehicle is running, the pulse signal output by the vehicle speed sensor is converted into a pulse signal of a certain frequency after frequency division and power amplification by the signal processing circuit, and acts on the electromagnetic coil of the stepping motor. The stepper motor converts this pulse signal into an angular displacement signal, which makes the motor shaft rotate, and drives the six counting wheels of the odometer decimal counter to rotate in turn, recording the total mileage and one-way mileage of the car. When you need to eliminate the short-distance mileage, just press the reset lever, and the short-distance odometer will be reset to zero.
1. When driving a car, the driving shaft rotates with a permanent magnet, and the magnetic field lines of the permanent magnet cause eddy currents on the aluminum bowl. The eddy currents and permanent magnets. The interaction of the magnetic field of a long magnet creates a torque that overcomes the elastic force of a disc shaped spring, and Wang Shi's aluminum bowl rotates around an angle with the pointer
2. The function of the speedometer refers to displaying the driving speed and cumulative driving distance, which is composed of two parts: the speedometer and the odometer. The driving shaft is driven by the transmission or transfer gear through a flexible shaft.
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