What is the speed of an automatic transmission car without pressing the accelerator?
2 Answers
Speed is approximately 5 to 10 km/h. There are three common types of automatic transmissions in cars: AT transmission, CVT transmission, and dual-clutch transmission. These three types of automatic transmissions differ in their working principles and structures. Below is an introduction to these three types of transmissions: AT transmission: Hydraulic automatic transmissions achieve automatic shifting through a combination of hydraulic transmission and planetary gears. They generally consist of components such as a torque converter, planetary gear mechanism, shift execution mechanism, shift control system, and shift operation mechanism. AT transmissions do not use a clutch for shifting, have fewer gears with significant changes, and provide smooth connections. CVT transmission: The characteristic of a mechanical continuously variable automatic transmission is that the gear ratio is not a series of discrete points but a continuous range of values. This allows for better coordination between the vehicle's external driving conditions and engine load, fully utilizing the engine's potential and improving the vehicle's fuel economy. Dual-clutch transmission: Dual-clutch automatic transmissions use two sets of clutches that alternately engage to achieve seamless shifting. They combine the advantages of AT and AMT transmissions.
When I drive an automatic transmission car, the vehicle will slowly creep forward without pressing the accelerator, typically at a speed of 5 to 10 kilometers per hour, which is equivalent to your brisk walking pace. On flat parking lots, this speed remains stable, making it convenient for turning and repositioning without constantly pressing the accelerator, which is quite hassle-free. However, it's different on slopes: when going downhill, the speed may increase to 15 kilometers per hour, and if you don't brake in time, it's easy to hit obstacles; when going uphill, the car may come to a complete stop or even roll backward, requiring extra caution. My car is an ordinary sedan, and the creep sensation at idle isn't very strong, whereas my friend's SUV clearly has more power. In daily driving, this creep feature makes it easier for beginners to handle, avoiding stalling issues, but it's important to develop good habits—always firmly press the brake or use the handbrake when parking, especially in crowded areas, to prevent accidents. This feature is cleverly designed: the engine's idle power pushes the transmission's torque converter fluid to move forward, eliminating the need for additional power from the accelerator.
