How is the mileage of a car calculated?
2 Answers
Calculated through mechanical odometers or electronic odometers. Below is a related introduction on how odometers calculate mileage: Mechanical Odometer: The mechanical odometer consists of a worm gear mechanism and number wheels. When the car is moving, the drive shaft rotates the rightmost first number wheel via three pairs of worm gears, displaying 1/10km on the first number wheel. From the first number wheel to the left, every two adjacent number wheels are connected through their internal teeth and carry-over gears, forming a 1:10 transmission ratio. When the first number wheel completes a full rotation from 9 to 0, the internal gear drives the second number wheel to the left to rotate 1/10 of a turn, incrementing the count by 1km. When the second number wheel completes a full rotation from 9 to 0, the third number wheel to its left rotates by 1/10, incrementing the count by 10km. The display and counting method of the remaining number wheels, from the lowest to the highest digit, follow the same principle, thereby displaying the car's mileage. Electronic Odometer: The electronic speedometer and odometer consist of a speed sensor (installed on the wheel's transmission worm gear assembly, utilizing photoelectric or magnetoelectric coupling), a microcomputer processing system, and a display. The photoelectric or magnetoelectric pulse signals transmitted by the sensor are processed by the microcomputer inside the instrument, displaying the speed on the screen. The odometer calculates and displays the mileage based on the speed and accumulated operating time, processed by the microcomputer.
I remember the car's mileage is calculated like this: when you drive, the wheels rotate, and sensors detect the number of rotations. The distance is calculated by multiplying the circumference of each tire by the number of rotations, which is then accumulated on the dashboard. Modern cars use electronic systems that update the mileage quickly when driving at high speeds; older cars might use mechanical gear counters, but these are prone to errors. For example, tire pressure affects the actual calculation—if the tires are underinflated, the mileage might be slightly overestimated. Mileage not only displays the total distance traveled but can also trigger maintenance reminders, such as oil change intervals. In used car transactions, it reflects the degree of wear, but some people cheat by tampering with the odometer, causing serious harm. It's advisable to regularly check if the sensors in a new car are accurate; otherwise, long-distance travel plans could go awry. The principle is simple, but precise execution is necessary to ensure safe driving.
