Many drivers, especially those accustomed to automatic transmissions or CVTs, perceive engine braking as something exotic — almost as a special function of old cars. Some even consider it a relic of the past. However, this is a serious misconception. Engine braking is not an archaic feature or a "hidden option," but a complete and important way to control a car.
It is a common belief that the phrase itself sounds contradictory: the engine, they say, is designed for acceleration, not deceleration. However, in practice, it is capable of performing the opposite task. Engine braking occurs when the gear is engaged, the gas pedal is fully released, and the crankshaft speed is above the minimum idle speed. In this situation, the roles are reversed: it is no longer the engine that drives the wheels, but the wheels are forced to rotate the engine, expending the accumulated kinetic energy of the car. As a result, the car decelerates noticeably faster than when coasting in "neutral."
What Exactly Brakes the Car
The key factor here is the resistance to the rotation of the crankshaft. It consists of several components. Firstly, it is the mechanical loss due to friction inside the engine. Secondly, it is the energy expended on compressing air in the cylinders. Additionally, all the units that are normally driven by the engine play a role: the generator, the power steering pump, the air conditioning compressor. During engine braking, they turn into energy consumers, increasing the overall resistance to rotation.
How to Brake Correctly on a Manual Transmission
In cars with a manual transmission, this method of deceleration requires conscious action from the driver. When approaching a stopping point, do not shift the lever to neutral in advance and coast. It is much more effective to release the gas pedal, continuing to drive in gear, and only then engage the service brakes. Shifting to "neutral" is only done immediately before a complete stop.
It is especially important to remember this on steep mountain descents. There, driving in low gears is not a recommendation, but a safety measure. A low gear significantly enhances the engine braking effect and allows you to keep the speed under control without overheating the brake mechanisms.
Automatic Transmissions: Easier Than It Seems
Owners of cars with automatic transmissions often ask: how to apply this technique without a clutch and manual gear selection? In most cases — not specifically. During uniform movement and subsequent release of the gas, engine braking occurs automatically, especially if the lock-up is active in the torque converter. The electronic control unit keeps it engaged until the last possible moment, providing an effective connection between the wheels and the engine.
However, on long descents, driver involvement is still necessary. If the gearbox allows manual mode, it is worth forcibly selecting a lower gear — third, second, or even first, depending on the slope. On older cars, this is done by moving the selector to the L, 2, or D3 positions, thereby limiting the possibility of shifting to higher gears.
CVTs and "Robots": The Same Principle
The situation is similar with CVTs. Despite the different design, they also use a torque converter, functionally similar to the one used in classic automatic transmissions. The lock-up algorithm remains the same. On flat sections, the system will do everything itself, and on steep descents, the driver must manually lock a low virtual gear.
In cars with robotic gearboxes, everything is even simpler: it is enough to select a lower gear in advance when driving downhill. If the road is flat, engine braking is implemented without additional actions.
Non-Obvious Factor — Energy Consumers
An interesting detail: the efficiency of engine braking directly depends on the number of energy consumers turned on. Air conditioning, power steering, a powerful audio system — all this, when decelerating, becomes an additional load for the wheels, making it difficult for them to rotate. At the same time, fuel is not consumed for the operation of these devices, since the fuel supply is stopped when the gas pedal is fully released.
Influence of Drive Type
There is another nuance that is rarely considered. The effectiveness of engine braking is also related to the type of drive of the car, especially in low-grip conditions — on ice, gravel, or loose surfaces. On such surfaces, small stones or ice behave almost like bearing balls, sharply reducing friction.
Since the front brakes are structurally more effective than the rear brakes, front-wheel drive cars in such conditions decelerate more confidently with the engine than comparable rear-wheel drive cars. This difference becomes especially noticeable on steep descents.
The Most Important Argument
And finally — the key point. Engine braking remains the only way to significantly reduce the speed of a car in the event of a complete failure of the braking system. This skill can be decisive. That is why it is worth not just knowing about it, but remembering and being able to apply it in practice.