how does tachometer work

• 2022-06-28

Generally speaking , the tachometer is divided into several areas . The white scale area is the safe speed range , the red scale part is the dangerous speed range , and some models are divided into green areas , which indicates that the speed is the most economical use range of the engine . Generally speaking , the vehicle speed is normal when it does not enter the dangerous speed range. However , pay attention to whether the vehicle speed is consistent with the current gear. Otherwise , low gear , high speed, low speed and high gear will cause unnecessary damage to the vehicle .

The speed of the engine must match the speed of the car, and there is a corresponding interval. Not all reference vehicle speeds . Ex factory engine oil is a special oil for running in cars: some old drivers and newcomers who have just bought a new car say that they should not change the ex factory engine oil into ordinary engine oil in advance . In fact , the oil in the running in period is more fuel consuming, which can be replaced in advance.

For the running in and maintenance of the engine, the lubricating oil with good quality shall be selected. Secondly, various operations such as oil feeding, starting, gear shifting and braking should be slow. Finally, the engine speed should be controlled at 2000-3000 rpm (gasoline engine), and the automatic gear should be controlled below 3000 rpm. If the engine speed is high, some parts will be strained, and if the speed is too low and the gear is too high, the parts will be worn.

There is a crankshaft speed sensor on the vehicle or ship engine. When the engine crankshaft rotates, there will be a pulse signal, which will be sent to the computer. After calculation, a control signal will be output and transmitted to the tachometer to control the rotation of the driving stepping motor on the tachometer (the pointer is directly installed on the rotating shaft of the stepping motor).

The faster the engine speed is, the more pulses are generated, and the greater the speed value displayed on the table . The tachometer also has a digital display. There is a digital integrated circuit inside . It drives the digital display after the voltage pulse is calculated.