What does engine braking mean for a car?

[VanEmilia]

Engine braking means: lifting the throttle pedal without depressing the clutch, using the compression resistance generated by the engine's compression stroke, internal friction, and intake/exhaust resistance to create a braking effect on the drive wheels. Here is some relevant information: 1. Modern cars have increasingly powerful engines and higher speeds, while internal friction losses are decreasing, which means the vehicle's own deceleration capability is reduced. At the same time, due to the increase in total vehicle mass, relying solely on the main braking system is no longer sufficient to meet braking demands under high-speed and heavy-load conditions. 2. To ensure safety performance, auxiliary braking systems must be added. Many countries (such as Germany, France, and Switzerland) have made auxiliary braking devices a mandatory requirement for commercial vehicles in their traffic regulations. Currently, the most mature auxiliary braking device used in vehicles is the retarder.

[Luca]

Engine braking, you see, refers to the process where you release the accelerator pedal while driving, and the car naturally decelerates by utilizing the internal friction and resistance of the engine. After driving for over a decade, I've found this technique particularly useful on mountain roads. When going downhill, constantly applying the brakes can overheat the brake pads, even risking failure; using engine braking makes it much easier, especially in manual transmission cars by shifting to a lower gear, letting the engine pull the car along, keeping the speed steady and controlled. Even on city roads, occasionally releasing the accelerator can result in a slight deceleration, helping me brake less in traffic jams, which is quite a relief. Automatic transmission cars also have this function, though the effect isn't as pronounced as in manual transmissions. New drivers might need some time to get used to this feeling, but it's truly a great aid for safe driving—don't overlook this skill.

[LeAnna]

I'm a relatively new driver and I'm particularly curious about engine braking. Simply put, when you release the accelerator, the engine acts like a small brake to help slow down the car, allowing it to gradually decelerate without constantly pressing the brake pedal. I tested this on a downhill slope in my neighborhood and could clearly feel the car being held back by the engine, with the speed steadily controlled, and the brake pads not overheating. This feels very similar to the sensation of slowing down by releasing the accelerator in racing games. However, I should remind everyone that the effect isn't very noticeable on highways because the wind resistance is too strong. Also, avoid suddenly downshifting in a manual transmission to prevent engine damage from excessively high RPMs. Overall, this is a practical driving technique that can save a lot of hassle during daily commutes. I recommend fellow drivers give it a try.

[VanNathan]

As someone who has worked in the automotive repair field, I understand that engine braking is a mechanism where the internal friction of air compression in the engine slows down the car when the throttle is released. In principle, it's caused by the resistance of piston movement after the intake valves close. Downshifting in manual transmissions enhances this effect, making it particularly effective for controlling speed on downhill slopes; automatic transmissions also have similar functions, but with more precise computer management. Using this technique can prevent overheating and wear on the braking system. During regular driving, I pay attention to keeping the engine RPM from getting too high to protect the components.