What is a speedometer and odometer? The difference between appliances

2024 Author: Erin Ralphs | [email protected]. Last modified: 2024-02-19 11:42

“No need to explain anything to me, I have 100,000 kilometers on the speedometer” - you can often hear such a phrase among arguing about cars. But the wording of the thought is completely wrong. If you analyze the speedometer and odometer, the difference between the instruments is obvious. It is the odometer that shows the mileage of the car, while the speedometer determines the speed of movement.

Deep in history

The oldest odometer is mentioned in the first century. The Greek mathematician Heron became the parent of this invention. The device was in the form of an ordinary trolley, the wheels of which were selected with a special diameter. The wheels turned exactly 400 times in 1598 meters (milliatria). Gear transmission set the simplest mechanism in motion. The run indicator was small stones that fell into the tray. To calculate the distance traveled, it was necessary to count the number of fallen stones. Since then, people have stepped far ahead in their inventions, but the idea itself was ideal.

Speedometer and odometer, the difference between which is not only in the testimony, have different dates of invention. The speedometer was invented just over a hundred years ago. Firstsuch a device was installed on an Oldsmobile car in 1901. For ten years, the speedometer was installed only as an additional option and was considered a curiosity. Later, factories began to install it as a mandatory device. In 1916, the speedometer was improved by Nikola Tesla. It has reached our days in almost the same condition, apart from some modern additions.

What is an odometer? Device and purpose

So, every motorist should know what a speedometer and odometer are for. The difference between these devices, of course, exists. Consider first the odometer. What role does it play in the toolbar? An odometer is a mechanism that is designed to measure the number of revolutions of the wheel while the vehicle is moving. In other words, this is a node that gives us the opportunity to find out the distance traveled by the car in kilometers. The odometer reading can be read from a special device on the machine panel. The odometer shows both daily and total mileage. These two scales are often located on the speedometer itself.

The design of the odometer is simple, it includes the following components:

• The counter itself, showing the number of revolutions of the wheel of your vehicle.
• A controller that records the revolutions and is directly connected to the meter itself.
• Indicator displayed on the speedometer. Shows the distance traveled by the vehicle in kilometers.

Odometer operation principle

Many novice car enthusiasts often hear the terms "speedometer" and "odometer". The difference between these devices is not known to everyone. We figured out what an odometer is, and now about the principle of operation of the device, how it functions. An odometer is an electronic or mechanical device that allows you to accurately determine the number of revolutions that a wheel has made. Such data enables the driver to accurately determine how many kilometers his car has traveled over the entire period of operation and not only. You can also find out how much the car has traveled for a particular time period. The data is displayed as a numerical value on the odometer indicator in kilometers.

This is the essence of the work of the odometer - the wheel of the vehicle for each kilometer of the distance traveled makes a strictly defined number of kilometers. This indicator is always the same. Knowing how many revolutions the wheel has made, the counter calculates the distance in kilometers.

If the driver needs to determine the distance traveled from point A to point B, he can always reset the counter. Thanks to this action, it is also easy to notice the fuel consumption for a certain path. Naturally, with a non-working odometer, such an operation is simply impossible to do.

Types of odometers

Considering the odometer and speedometer (there is a difference between them in the structure), let's decide on the types of odometers. There are three main types:

Mechanical. The oldest type, its progenitor wasinvented by the ancient Heron. If you need to wind such an odometer, you can do this with any twist. With the help of a digital counter, the rotation of the wheel of the mechanical component is taken into account. Under the influence of mechanical forces, the counter reads the revolutions and converts them into kilometers. The disadvantage of such counters is that when a certain figure is reached, the readings are automatically reset to zero

Electronic-mechanical device. More advanced odometer model. To correct such a counter, the use of CAN twists is already required. In this case, the wheel revolutions are read by the counter using a mechanical connection, subsequently the information is converted into signals. Data is digitally displayed on the dashboard

Digital odometers. They operate on the basis of a microcontroller. The most modern device. All necessary indicators in this case are read in digital format. To correct such an odometer, you will need the use of special equipment. The digital odometer is part of the vehicle's on-board computer

Odometer error

Everyone knows that any modern devices in their work have some inaccuracies. There are some standards that allow errors. For mechanical devices, for example, this figure is allowed at 5%. If the vehicle is operated in any harsh conditions, then this figure can increase up to 15%. In such cases, there is a discount for the wear of various parts, vehicle components (for example, slippage). Formally, in this casethere is a rotation of the wheels (supposedly there is a movement), but the distance in kilometers does not increase.

Both the odometer and the speedometer can show a certain error in operation (the difference between these devices is now clear). Also, the readings of the device are affected by various gaps, loosening of the cable, poor grip, weak springs. Electromechanical devices read the signals that the speed controller indicates for a certain period of time. In these cases, the error is lower, the accuracy is higher. Cars with electromechanical devices, even very old ones, rarely give an error of more than 5%. Digital devices are the most accurate, mechanical links are not involved here. If such devices have an error, then this is directly related to wheel wear.

What is a speedometer

Speedometer is a device that measures the instantaneous speed of a vehicle. Meter readings are displayed in km/h (kilometers per hour) or - in America - miles per hour. There are two types of speedometers: mechanical (analog), digital. How does the speedometer work and what does it show? In a rear-wheel drive car, the speedometer controls the rotation of the output shaft at the gearbox, in which case the speed is calculated from it. Accordingly, the speed readings will depend on the tire size, the gear ratio from the rear axle, as well as on the instrument's own error. For front-wheel drive vehicles, speed is measured using the left wheel drive. The rounding of the road is added to the error of the speedometer. Wewe examined the odometer and speedometer above (the difference is what they serve for, the principles of operation). Now let's find out the reasons for the errors of the speedometer.

Why is the speedometer lying

If you look at the car's speedometer, it's easy to guess why he's lying. Why does it show overspeed? Firstly, the driver is less likely to break the speed limit and get a fine. Secondly, if the speedometer indicated a lower speed than the real one, then, most likely, the drivers would not stop suing automakers, proving their innocence of speeding. Does the speedometer have to lie? The fact is that this device is the most difficult to indicate super-accurate readings, because the speed depends on the rotation of the wheel, on its diameter, and this is a very unstable parameter.

The error of the speedometer at a speed of 60 km / h is very minimal, it is practically non-existent. At a speed of 110 km / h, the error can be 5-10 km / h. If the car speeds up to 200 km / h, then the average error can be up to 10%. We answered your question "what is an odometer and a speedometer". The difference is now clear. Let's summarize. All of the above makes it possible to draw the following conclusions.

Odometer and speedometer: instrument difference

As already mentioned, not all motorists understand the difference between two different instruments - an odometer and a speedometer. Some are misled by the fact that the odometer is directly built into the speedometer itself. That is why many consider thisdesign for one device. What is an odometer and speedometer? The difference between the functionality is obvious. Confusing these devices is simply unacceptable. To be brief, then:

• The speedometer shows the speed of the vehicle.
• The odometer indicates the distance traveled in kilometers.

Their functionality is in no way interconnected. The combination of these two scales on the dashboard is determined only by the convenience for the driver to perceive. However, modern on-board computers display this information among the main information.

Why twist the mileage

“Twisted the speedometer to reduce mileage” is also an incorrect expression among motorists. We told you what both the odometer and the speedometer are for. The difference and photos of these devices indicate that in order to reduce mileage, the readings are twisted not from the speedometer, but from the odometer. Why do they do it? Everyone justifies these desires in different ways. Device malfunction, replacement of the entire panel, driving on non-standard rubber. To be honest, the reason is almost the same - everyone wants to "rejuvenate" their vehicle. Often this happens when selling a car. There are those who want, on the contrary, to increase mileage. Often these are drivers of commercial vehicles who use cars for official purposes. After all, very often fuel consumption exceeds the norms allowed by the accounting department, which do not take into account depreciation, wear and tear of the vehicle. To compensate for these costs, drivers use such a trick as increasing mileage.