What is the working principle of engine braking?

1 Answers
MirandaFitz
07/30/25 5:23am
Engine braking utilizes the compression resistance, internal friction, and intake/exhaust resistance generated during the engine's compression stroke to create a braking effect on the drive wheels. The specific principles of engine braking are as follows: 1. Engine braking refers to when the throttle is released: during the compression stroke when the piston is near the top dead center position, the exhaust valve momentarily opens to release the high-pressure gas. 2. Closing the exhaust valve: there is very little gas in the cylinder, and when the piston moves from the top dead center downward during the explosion (expansion) stage, the cylinder is in a negative pressure state. 3. The gas resists the downward movement of the piston: the piston essentially creates a vacuum, generating torque in the opposite direction of the crankshaft, thereby producing a braking effect.
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