what is a tachometer on a watch

• 2022-07-12

Nowadays, the degree of automobile electrification is getting higher and higher. Automatic transmission, reversing video, electronic aids and other equipment have been fully popularized to household vehicles, and many vehicles can be close to the form of semi-automatic driving. I believe many people are confused that almost no one will notice the tachometer, but why put it in the most prominent position? Some sports cars even highlight the tachometer. I believe that the design of the car must have its reason. Let's take a look at the functions of the tachometer.

The tachometer is generally set on a watch. It receives the pulse signal generated when the primary current in the ignition coil is interrupted. And convert this signal into a speed value that can be displayed.

The speed of the engine at the moment of starting is high, which can generally reach 1200-1500/min, and may be even higher in cold weather -- this is the case with all EFI vehicles.

Many people think that a hot car in winter needs to wait until the engine speed reaches the idle speed of the whole car. In fact, it is not. As long as the engine idle speed is stable and there is no obvious fluctuation, and the speed drops to about 1000r/min, it can start. Generally, this process only needs the effort of getting on the car, fine adjusting the seat, wiping the front windshield and fastening the safety belt.

In a fixed gear, the speed is closely related to the speed. For example, 1 KK of 2 is at the speed of 60 in gear 4, and the speed must be 2000 at this time. If you know any two values, you can deduce the third value. For example, if you know the speed of 2000 and the speed of 60, you will know that the gear must be in gear 4. No matter what road conditions, whether you step on the accelerator or not, this correlation exists. For example, if you do not step on the accelerator at all on the next steep slope, the speed is still 60 and the speed is 2000 in gear 4. This correlation is the basis of speed shifting. It is similar to the principle of speed shifting, but there is no need to remember the speed of shifting.