1：Did you know?
The number of gear positions generally refers to the number of forward gears in a gear-based transmission. The more gear positions, the better the adaptability of the vehicle to different driving conditions, which can reduce fuel consumption. Nowadays, the number of gear positions in transmissions typically ranges from 4 to 8. Among the gear positions, the ones with lower numbers are called lower gears, while those with higher numbers are called higher gears.
2：Principle
The power output from the engine's crankshaft is transmitted through the clutch and directly input to the input end of the transmission. At this point, the engine speed is relatively high, while the torque is low, making it unable to directly drive the wheels. It must go through a series of speed reduction and torque increase processes to propel the wheels forward. The number of gear positions also has a significant impact on the power performance. With more gear positions, the first gear can have a higher gear ratio, allowing for higher torque output during acceleration.
3：Further Reading
There is also a concept of an overdrive gear on the transmission, where the output shaft speed is higher than the input shaft speed. It is mainly used for vehicles with certain power reserves to achieve high-speed driving on good roads. This helps reduce engine speed, fuel consumption, engine noise, and wear. Additionally, there is an O/D control switch located below the gear lever, which, when activated, automatically engages the overdrive gear in the "D" gear position. When the switch is turned off, the O/D off light on the instrument panel illuminates, and the "D" gear position can only go up to the 3rd gear. The three functions of limiting gears, "1," "2," and "D+O/D-off" (equivalent to limiting to the 3rd gear) restrict the automatic transmission's shifting function to achieve a continuous increase in engine speed, facilitating power and torque output. Therefore, they are referred to as "limiting gears."
