What is the purpose of engine brakes?

The primary purpose of engine brakes, also known as compression releases or Jake brakes, is to assist in slowing down the vehicle. When the driver activates the engine brake, it changes the way the engine operates, allowing it to create resistance against the motion of the vehicle. This resistance helps to reduce the speed of the vehicle without the driver having to rely solely on the traditional service brakes. By doing this, engine brakes can help maintain vehicle speed on downhill grades and can reduce wear on the brake components, leading to a longer lifespan for the braking system.

This functionality is particularly valuable in heavy vehicles, where braking can be more challenging due to the mass and momentum of the load. Therefore, effectively using engine brakes enhances safety and control when descending slopes, as they help manage vehicle speed in a controlled manner.