What Is Engine Braking?
Pressing the brake pedal is only one way to decelerate your vehicle while driving. Assuming you own a modern vehicle, you can probably use engine braking as well. It's a common feature found in most cars, trucks and SUVs manufactured during or after the 1990s. To take advantage of engine braking, though, you must first understand how it works.
Overview of Engine Braking
Not to be confused with compression-release braking, engine braking is an automotive feature that allows drivers to decelerate their vehicle by removing their foot from both the gas pedal. Modern vehicles use combustion engines that require fuel, air and spark. When you release your foot from the gas pedal, the intake manifold on your vehicle's engine closes, thereby restricting airflow. In turn, negative pressure builds up inside the intake manifold -- and the engine's cylinders must work against this pressure.
In other words, engine braking doesn't rely on pads and rotors to decelerate your vehicle. It uses the internal forces within the engine, including compression as well as friction, to slow down your vehicle.
Benefits of Using Engine Braking
Engine braking offers several benefits, one of which is reduced wear and tear on your vehicle's brakes. If you're guilty of pressing the brake pedal each time you need to decelerate, you can expect to replace your pads and rotors more frequently. Each time you press the brake pedal, it will create friction on the pads and rotors, which over time will cause them to degrade until they must be replaced. Engine braking doesn't create friction on neither the pads nor rotors, however, so it can extend the life of your vehicle's braking system.
Engine braking is also better for your vehicle's engine than using the brake pedal. When engine braking occurs, your vehicle will use its internal forces to slow down. As a result, it won't "fire" mixtures of gas and air. You may notice a slight increase in RPMs, but this is completely normal and shouldn't cause reason for concern. In fact, it will extend the life of your vehicle's engine while offer cost-savings benefits for gas consumption in the process.
Engine braking is simply a feature in modern vehicles that uses the engine's internal forces to decelerate rather than brake pads and rotors. When you remove your foot from the gas pedal, air stops entering the intake manifold, thus creating negative pressure that slows down your vehicle.