A car tachometer is a device thatused to determine the number of revolutions of the rotating parts of the engine running. The measurement is performed per unit of time or according to the speed of linear motion. The automobile tachometer helps in choosing the right gear and, as a result, contributes to extending the life of the power unit. This means that at the moment when the needle of the device approaches the red zone, you should immediately shift to a higher gear. Car tachometer often used for adjustment work:at idle and for the purpose of operational control of the speed of rotation of the motor shaft when the car is moving. The principle of operation of such a device consists in registering pulses from sensors. In addition to counting their number, the automobile tachometer records the order in which they are received, as well as the pause between the counted pulses. At the same time, the calculation itself can be done both in the direct way and in the opposite way, and if necessary, mixed, that is, in both directions.
As a result, the indicators obtainedare transformed into various quantities, such as seconds, minutes, hours, meters, etc. If necessary, the automobile tachometer can be reset, thereby resetting all collected values. However, when using such devices, it must be remembered that the accuracy of the measured data is very arbitrary and is about 500 rpm, for the best electronic devices it reaches 100 rpm.
Car tachometers are of two types: analog and digital.
Digital devices are made in the form of electronicscoreboard, which displays all the counted information, namely the number of revolutions of the engine and shaft. Such a tachometer is very useful when carrying out adjustment work with an electronic ignition unit of automobile engines, as well as when setting thresholds in an economizer, etc.
Analog devices are very popularin the automotive industry. They show the number of revolutions of the power unit by means of the dial. The operation of such a device is made by electronic principle. This means that the signal from the sensor located on the motor shaft is transmitted to the microcircuit. The latter sets the movement of the pointer (arrow) on the graduated scale. Any analog automobile device and tachometer for the outboard motor work on the same principle. The first is an elementary pulse counter electrical engine. It directly depends on the frequency of rotation of the crankshaft. The tachometers of outboard motors also consider electric impulses, but they receive "information" directly from the magdino lighting coil, which plays the role of a generator.
In any car makes sense additionallyhave a digital tachometer. It is useful for regulating idling and checking the operability of the economizer control unit, as well as the correctness of the standard analog device. This is due to the high measurement accuracy of digital devices. However, when driving a car, it is better to use a dial gauge, as it is more visual for the driver.
