Mileage sensor failure will cause the car's odometer needle to stop moving, and the mileage will not increase. Speedometers can be divided into three types: purely mechanical, mechanical-electronic, and purely electronic. Below are the specific details: 1. Purely mechanical: In a purely mechanical speedometer, the flexible shaft rotates at high speed. The hysteresis of its movement and the limitations imposed by the alternating stress limit of the steel wire often cause the flexible shaft to fatigue and break in high-speed vehicles, leading to odometer failure. As a result, purely mechanical odometers are gradually being phased out of the market. 2. Mechanical-electronic: Compared to purely mechanical speedometers, the mechanical-electronic speedometer primarily replaces the flexible shaft with a sensor, overcoming the drawbacks of needle oscillation and flexible shaft breakage in mechanical speedometers. The transmitted photoelectric or magnetoelectric pulse signals are processed by the internal computer of the instrument and then displayed. 3. Purely electronic: The purely electronic speedometer eliminates the error in vehicle speed and mileage caused by the difference between the actual and theoretical speed ratios of the odometer's driving and driven gears, making its readings more accurate than the previous two types. Additionally, the reduction in interacting transmission components decreases both the failure rate and cost, which is why this type is widely used in the domestic bus industry.
