Why lie speedometer? Bashny.Net

Continuing the theme of "Week of simple questions».

The fact that in reality the car's speed is always slightly less than the speedometer shows - not a secret for most motorists. But why this has become a tradition? The true speed can easily show anyone, even an inexpensive navigator - why automakers continue to "cheat»?





Why is "lying" speedometer?

With regard to the speedometer - not hard to guess why he was "exaggerating." Firstly, the driver will be less likely to break the speed limit and get a penalty. Second, if the speedometer underestimated the actual speed, the drivers would wear out automakers in the courts, arguing that all the trouble (fines, accidents, breakdowns) happened to them because of incorrect readings.

Mean error in modern speedometers - 10% at a speed of 200 km / h. Moreover dependence usually nonlinear. This means that at 110 km / h the difference with the actual speed may be 5-10 km / h, and at speeds up to 60 km / h almost no errors.

But why the speedometer must "lie"? The fact that it is difficult to be more precise than many other devices. Because speed is usually determined by the speed of rotation of the wheels (more precisely, the readings are taken from one of the shafts in the transmission, but the speed of rotation of this shaft is directly proportional to the wheel speed). This speed depends on the diameter of the wheel, and that - an unstable setting.

According to rumors, the error of the digital speedometer is reduced to zero, and is only 1 km / h. In fact, a digital speedometer and deceiving a plus, showing a rate greater than it actually is.

"The wheel can be dropped down or pumped, the winter air in a tire temperature in the summer - another. All this affects the diameter of the wheel and as a consequence - on the speedometer, - says Andrey Glazkov, marketing director of the Russian office of Mazda. - Not to mention the fact that the driver can put the wheels in diameter by a few inches longer than standard. Therefore, to create a high-precision speedometer in theory it is possible. But it will cost dearly. Incidentally, the prestigious German cars, as far as I know, there are speedometers with minimum error - but the price of these machines can not be called democratic ... »

Many believe that the more accurate digital speedometer switches, but in reality it is nothing more than a delusion. "Digital speedometers are indistinguishable from analog: a mechanism to measure the speed of the same, only different method for displaying the results of these measurements," - says Maxim Neupokoev, training manager of the Russian representative Porsche.

The idea is to get a high-precision speedometer is not too difficult: it is enough for the role of the data source to select GPS-module standard navigation system. So certainly happen when navigation becomes an integral part of the car, not extremely expensive option. In the meantime, drivers still put up with a small "a liar", constantly looming in front of his eyes.

ALL. You can kick.



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