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does the speedometer of a car read average
The speedometer indicates the speed of the vehicle. It shows the instantaneous speed, which is why the pointer shakes. You will understand the principle of the speedometer below. The indication of the speedometer depends on the speed sensor, which is installed on the gearbox. Different pulse signals are obtained through different speeds, and then converted into pointer output, which is the current speed you see. The regulations require the speedometer to display slightly higher than the actual speed, which is for safety. Another is the speed of liquid crystal display. The principle is similar to the above, and the indication output is replaced by liquid crystal display.
The indication of automobile speedometer is instantaneous speed. The following is the specific introduction of the speed sensor: 1. Working principle: the speed sensor is composed of permanent magnet, magnetic pole, coil and ring gear. When the ring gear rotates in the magnetic field, the gap between the top of the ring gear and the electrode will change at a constant speed, making the magnetic resistance in the magnetic circuit change. The magnetic flux will increase or decrease periodically, and an induced voltage proportional to the increase or decrease speed of the magnetic flux will be generated at both ends of the sensor coil, and this AC voltage signal will be directly transmitted to the control computer of the car, so as to ensure the stability of the car. 2. Installation position: it is generally installed in the drive axle housing or transmission housing, while the signal wire of the sensor is installed in the shielded jacket.
1.If the actual speed of the car is 40km\/h, the indicated value of the speedometer should be between 40km\/h and 48km\/h;
2.The general requirements, indication errors and test specifications of vehicle speedometer under loading state stipulate that the indicated speed of speedometer shall not be lower than the actual speed, and the relationship between the indicated speed and the actual speed shall conform to the relationship of "0 ≤ indicated speed - actual speed ≤ actual speed \/10+4km\/h";
3. Current models mainly calculate the speed by the number of revolutions of tires. For example, Suzuki models calculate the average fuel consumption and mileage by converting the ABS wheel speed signal into the vehicle speed signal. Simply speaking, they also calculate the average fuel consumption and mileage by the number of revolutions of the tires. The speedometer indicates that the vehicle speed is high, and the standard values are still used to calculate the average fuel consumption and mileage. Therefore, although the indicated speed is higher than the actual speed, it does not affect the average fuel consumption and mileage.
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