Why does the engine speed increase when going downhill?

[Darlene]

When going downhill, the high engine speed is due to the potential energy gained from gravitational acceleration as the vehicle moves from a higher to a lower elevation. Even without pressing the accelerator, the vehicle will accelerate downhill. However, the engine's reverse traction force will slow the vehicle down. When the slope is steep, the gravitational acceleration acting on the vehicle exceeds the engine's reverse traction force in the current gear, causing the engine speed to rise. Here are some precautions to take when going downhill: Do not rely solely on low gear to control speed: To avoid overheating the brake pads from prolonged braking, engine braking is used, but this does not mean you should avoid using the brakes altogether. Even if the gear is set to a low position, if the downhill slope is steep or long, the engine speed may still be forced to increase. In such cases, you should use the brakes to assist in slowing down. Engine braking in automatic transmission vehicles: For automatic transmissions, engine braking requires shifting to L (Low) or S (Sport) mode in manual mode to effectively utilize the engine's braking force.