A tachometer is an integral part of every car. This device is used to determine the number of engine revolutions, the value of which is then displayed on a special scale. As a rule, this measurement process takes place in a matter of milliseconds, due to which the driver can receive only reliable information about the current state of the “engine” of his car. What is the special device “tachometer” and how it works, you will learn in the course of our today's article.
Functions
The main task of this device is to facilitate the selection of the necessary (or rather, correct) transmission on the gearbox, which significantly increases the dynamics of the vehicle and the motor does not “suffer”. For beginners, for reference: engine operation at lower or higher revolutions entails a significant load on all parts of the crankshaft, as a result of which the resource of the motor and gearbox is significantly reduced. Thus, the tachometer is a kind of “adviser” that shows the driver the current engine speed and thereby indicates the need for switching to higher or lower speeds (respectively, if the arrow has dropped or has gone beyond the green scale).
Principle of operation
The main essence of such a device as a tachometer is the registration and control of the number of pulses from the crankshaft sensors. It is from the sensors, so do not think that the tachometer cable is wound somewhere on the crankshaft or something else. It is also worth noting that the counting of pulses can be carried out both in the forward and in the opposite direction (in some cases, even in both directions).
The value that is measured by the sensor is displayed on a special scale. Here, the main measurement is the number of revolutions per minute (rpm). Moreover, deviations in the range of several hundred revolutions are possible on the pointer devices (on the scale itself, the run-up from 2 to 8 thousand rpm is often indicated). On electronic devices, a more accurate reading is displayed. Speaking of varieties.
Kinds
At the moment, there are two main types of devices such as a tachometer. These are gauge switches (they are also often called analogue) and digital type. The first variety is the most ancient and at the same time reliable. Despite the fact that the electronic digital tachometer is a much accurate and functional instrument, many drivers prefer to use the arrow mechanisms. The fact is that readings from such a scale are very easy to read, while electronic ones take a very long time to get used to. And let the arrow be inaccurate in the readings, but it is more convenient to read. And the main thing for the engine is that the speed does not go beyond the green scale. And the fact that there is a difference of 100-300 rpm is not very significant.
Conclusion
Thus, the tachometer is a very useful measuring device (although not required), which quickly reads the crankshaft speed and displays these values on a special scale.