What is Engine Braking? A Comprehensive Guide

Did you know that if you are driving your vehicle on a steep slope you can control the speed of the car by merely using the engine without touching the accelerator. Well, most of the people are unaware of this method. Now, You can control your car’s speed by simply using the technique of engine braking. But wait, how does it work and why do we use it?  Let’s break it down.

What is Engine Braking?

Engine braking simply means to control your vehicle’s speed using the engine by shifting to low gear mode and taking your foot off of the brake pedal. It utilizes engine resistance rather than the traditional method of brake pedal. To do this technique, you have to lower the car’s transmission gradually. This is done to reduce the workload of the brakes and to ensure smooth drive. Although it can be used in both manual transmission vehicles and automatic transmission vehicles, it works best in manual transmission vehicles. This braking mainly depends on the condition of the vehicle’s motor and the steepness of the road. The way of motor braking can be adjusted according to your needs on the road.

How Does Engine Braking Work?

When the driver lifts off the accelerator, the throttle valve closes reducing the amount of air entering the engine. With less air, the engine’s pistons try hard to move, creating a braking effect. This process causes the car to slow down naturally. In manual cars, the driver controls this mechanism completely by downshifting and it’s stronger but requires skills and practice but in automatic cars, the car does most of the work. It does not require much skill and it’s for the drivers who prefer simplicity.

Types of Motor Braking

There are two main types of motor braking systems which are fowling below:

• Throttle off engine braking(gasoline engines)
• Diesel engine braking

Throttle off engine braking(gasoline engines)

In gasoline engines, this process occurs when the throttle plate closes, restricting the airflow in the engine causing the engine to resist and create stopping effects without actively applying brake pedal. It works in almost all vehicles.

Diesel engine braking

Diesel engines do not contain throttle valves. Instead, they have some specialised systems to enhance this mechanism effeciency:

• Compression release engine brake: also known as jake brake is an engine retarder that alters the operations of the engine’s exhaust valve converting the engine into power absorbing air compressor. This is commonly used in heavy-duty trucks or buses
• Exhaust brake: this braking system closes the exhaust path creating immense pressure in the exhaust system. As a result, backpressure is built on the engine making the engine work backwards and causing the vehicle to slow down. It is used in smaller trucks where Jake brake is not available.

The basic difference between gasoline engine braking and diesel engine braking lies in how they resist the air flow to stop the vehicle. Gasoline engines restrict airflow by closing the throttle and diesel engines use exhaust resistance to slow down the vehicle.

Engine vs Regular Braking

Features	Engine Braking	Regular Braking
Working	Uses engine resistance to slow down vehicle	Use brake pedals to slow down the vehicle
Best use	Steepy areas, downhills, brake failure, reducing brake wear	Emergency situations, busy roads or heavy traffic, increases brake wear
Control	Smooth deceleration	Immediate stopping
Effects	Minimal heat generation, and fuel efficiency, require skill	No effect on the engine, More fuel consumption, overheating

Advantages of Engine Braking

 The first and foremost benefit of motor braking is that it saves fuel. 

• When the driver slowly stops the car the engine stops using fuel. 
• It also reduces wear on your brake pedals enhancing their work life and providing smooth drive, especially in hilly or steepy areas. 
• It prevents overheating of brake pads providing full control to the driver.
• With the engine brake, the braking process will be faster and more spontaneous as the driver will skillfully shift the gear.

Limitations of Resistance Braking

Along with the benefits there are some disadvantages of compression braking which are following below.

• If not done correctly it will cause damage to the engine. 
• In some emergencies or critical situations motor braking will not be a good idea.
• While driving on an icy or slippery road you must be careful about slowing down the car.
• This process can be risky in heavy traffic causing trouble to you.
• Listen to your car while braking with the engine, if your car is not built for it use traditional method of instead of this.

You can also read the technical overview of the TD5 timing chain here.

When to Use Engine Braking?

When you want to slow down the vehicle and save the brake pedal from overheating, especially in frequent braking drive, engine braking is best. It slows down the car without using brake pedals which means less wear, less heat and less fade.

It is most beneficial when you are driving down very steep and long slopes. It helps avoid sudden strokes and jerky movements. Engine braking does not harm your engine. Rather it makes your engine more active and efficient.

Continuous use of foot braking can overheat the brakes so combining engine brake lightly with regular brakes can be advantageous. It helps reduce fuel consumption as compared to regular braking and maintains vehicle control.

In case of an emergency like brake failure, engine braking can be used as a life saver to slow down the vehicle. In certain circumstances like, approaching a tight turn, shifting to lower gear can improve handling the situation.

When carrying a heavy load the vehicle’s momentum increases making it harder to stop, drag braking can be helpful as it provides strength to the vehicle reducing the strain. With engine brake you can reduce the risk of accident especially on downhill roads.

It’s the efficient way of slowing down smoothly. Sometimes it may produce engine noise but it is not harmful to your vehicle. You just have to downshift gradually to match the engine’s speed (which of course requires practice and skill). Once you are familiar with this technique you can do spontaneous acceleration.

Conclusion:

To sum up, what is engine braking? is a useful technique to slow down the car by using the engine’s natural resistance rather than regular braking method. This requires shifting to lower gear in a manual transmission or applying low mode on an automatic transmission.

Braking can be adjusted according to the engine condition, the experience of the driver and the circumstances on the road. This process also saves fuel, decreases the load on the accelerator, and ensures smooth drive and full control but it requires a lot of practice and skill. 

Frequently Asked Questions

Does engine braking damage the vehicle?

A prevalent myth is that engine braking harms the vehicle’s engine. However, if done correctly it does not cause any damage because the vehicle’s engine is designed to handle pressure involved in engine braking. Rather the engine is lubricated continuously in this process which ensures safety.

Is engine braking effective at all speeds?

No. It works best in moderate speed and low gears. At low speed, it can work but at very high speed sudden transmission can cause wheel slip.