how to use a tachometer on a watch

• 2022-02-18

One day, your co driver, an old driver or your driving coach, said to you in an indisputable tone, "how many times have I told you to change gears at 2000 rpm? Why can't I remember?", Whether right or not, you must remember the number of 2000 revolutions at this time. It is the sacred and unshakable shift condition in their mind that the old drivers told you! In the car, there are two largest instruments, speedometer and tachometer. They are generally symmetrically installed in the center of the instrument panel and occupy the vast majority of the instrument panel. Speedometer is of great concern to everyone. On the one hand, it is used to display the speed of the car to avoid speeding and violation of regulations; On the other hand, the mileage can be displayed. But for the tachometer, many people don't know how to use it, and even think it is redundant. In fact, tachometer is very important for cars.

Although the speed is only a parameter of the engine, as in the above scene, the tachometer can convey a lot of important information.

1. The invention of tachometer indicating the running state of engine was earlier than that of automobile. It was first used to detect the rotating speed of rotating equipment to ensure that it operates in a safe rotating speed range and prevent equipment damage. In the field of automobile, it was first used in racing. It is difficult for racing drivers to judge whether the engine has reached the maximum speed through sound, but they have to squeeze out the last trace of engine performance, so the introduction of tachometer can give intuitive instructions to drivers.

2. It indicates the safe operation area of the engine, but at too high speed, the lubrication and heat dissipation effect of the engine is poor, and the speed is too high, which exceeds the bearing capacity of some engine parts, which will cause damage to these parts. Therefore, red line areas are set on the tachometer of early vehicles to remind the driver that at this time, the engine works in an unsafe area and waves will continue, The engine is about to be washed away.

3. Identification and labeling from 1950, cars began to be equipped with tachometers. The first batch was equipped with some high-performance sports cars, most of which will be driven to the waves or on the track. Therefore, in addition to the important information of speed indication, the tachometer also has an identification function. Up to now, all cars are equipped with tachometers, even electric vehicles with engines. But the tachometer can still be used as an identification tag. For example, the red line mentioned above can be said to have lost its original function of indicating unsafe working areas, because the current engine control technology will be equipped with speed limit function, which will not let the engine run to this unsafe area. The red line can be said to have degenerated into habitual signs and labels. For example, the 7300 red line of Johnny Che Shen's car in Scene 2 above can be said to be the label and identification of the vehicle to some extent.