what is a tachometer in a car

• 2022-01-05

Rotational speed is the physical quantity of the ratio of the number of revolutions of a rotating body to time. In engineering, it is usually expressed as rotational speed = number of revolutions / time. It is an important parameter to describe the rotational motion of an object. Electricians often need to measure the speed of motor and its driving equipment. Portable tachometer is used. Tachometer is an instrument used to measure motor speed and linear speed. There are many kinds of tachometers, including mechanical centrifugal tachometer and digital electronic tachometer.

The tachometer of machine machine refers to the speed of machine machine, that is, the speed of machine per nanosecond. The tachometer is often put in the instrument panel and together with the speedometer.

The tachometer works according to the glamorous principle. It receives the palpitation signal generated when the primary current in the ignition coil is intruded and converts this signal into a displayed speed value. The briskly the machine speed, the further beats generated by the ignition coil, and the lesser the speed value displayed on the table.

Speed: 1 ~ 99999 rpm
Frequency: 0.0167 ~ 1666.6 Hz
Cycle: 0.6 ~ 60000ms
Count: 1 ～ 99999
Linear speed: 0.1 ~ 3000.0m/min
Measurement accuracy of tachometer: ultra-high accuracy (speed, frequency and cycle) with error of < 0.02% in full range
Measuring distance of tachometer: photoelectric type: 50 ~ 300mm; Laser type: 50 ~ 3000 mm
Display: five significant digits dynamic LCD floating point display
Signal output: TTL level pulse output
Power supply: Powered by two No. 7 batteries, it can be used continuously for 24 hours

The engine speed, gear and vehicle speed are matched. All automobile engines have a speed that outputs the maximum torque. When the gearbox is in a certain gear (except the highest gear), when the engine speed reaches the speed that outputs the maximum torque (e.g. 3000 rpm), the vehicle speed must reach the highest speed that this gear can withstand, and then it is necessary to shift (upshift).

Generally, when the speed increases to a certain extent, the engine working noise will increase. At this time, it is necessary to upshift. The shift time is generally between 2500 ~ 3000 R / min.