What is Exhaust Braking?
2 Answers
Exhaust braking is a type of vehicle auxiliary braking method, commonly known as exhaust brake or engine compression brake. It is achieved within the engine. Many vehicles use this method by closing the engine's exhaust passage, causing the engine pistons to encounter gas backpressure during the exhaust stroke, which hinders the engine's operation and generates a braking effect, thereby controlling the vehicle's speed. When using exhaust braking, it is not allowed to shift into neutral or disengage the clutch. The exhaust braking system consists of an exhaust brake button valve, a waste gas working cylinder, an exhaust brake butterfly valve, and a fuel shut-off cylinder. Driving on icy, snowy, or slippery muddy roads with exhaust braking can reduce side slipping. When descending long slopes, using exhaust braking can decrease the frequency of service brake usage, lower the temperature rise of the brake drum, and enhance braking reliability.
The exhaust brake has been my essential tool for twenty years of truck driving, especially during long downhill sections on mountain roads. When activated, it closes the exhaust valves in the engine, making the vehicle feel like it's being dragged, gradually slowing down so I don't have to constantly apply the brakes. This reduces brake pad wear, extending their lifespan by several years and avoiding the risk of overheating and fire. I remember last winter on a snowy highway—it was all thanks to the exhaust brake keeping my speed steady, or else things could have gone wrong. Operation is super simple—just press a button—and it's commonly found only on diesel vehicles. For maintenance, check the exhaust valve every six months to ensure it doesn't get stuck. It's low-cost but offers significant safety benefits. I highly recommend all heavy-duty drivers learn how to use it—it brings peace of mind and saves money.
