What is the principle of engine cylinder braking?

[DeBenjamin]

Cylinder 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 following are relevant details about cylinder braking: 1. Cylinder braking refers to the momentary opening of the exhaust valve near the top dead center position of the piston during the compression stroke when the throttle is released, thereby releasing high-pressure gas. 2. After closing the exhaust valve, there is very little gas left in the cylinder. During the explosion (expansion) phase, when the piston moves downward from the top dead center, the cylinder enters a negative pressure state. 3. The gas resists the downward movement of the piston (the piston effectively creates a vacuum), generating torque in the opposite direction of the crankshaft, thus producing a braking effect.