What is an engine brake?

What Is An Engine Brake?: Understanding the Function and Benefits

Braking by stepping on the brake pedal is the primary method to slow down your vehicle while driving. However, frequent use of the brake pedal can lead to brake wear and reduced effectiveness over time.

So, to stop your brakes from getting worn out and make your braking component last longer, there is a method called engine braking. But What is an engine brake? How does it work?

Engine braking is a method that slows down your car without pressing brakes, meaning you just stop accelerating, so the engine loses power, and the vehicle slows down eventually. This method can make your car’s fuel economy more efficient and extend the life of your brakes. Engine braking is widely used in large vehicles like trucks and buses, But they are equipped with Jake brakes different than usual brakes. 

In this post, we will talk about engine braking and its benefits. 

So, without further ado, let’s dive into this topic.

What Is an Engine Brake?

In vehicles, usually, you slow down by pushing the brake pedals. This is all known to us as it’s the most usual way of slowing down vehicles. But constantly using your brake pads makes your brakes wear down, and eventually, they may get worn out, which can get disastrous for you because we all know if a car brake system doesn’t work, it’s prone to crash more.

So to make your brake last longer, here comes the engine braking method to your rescue. Engine brake stops your car without adding additional force, which means if you stop pushing your gas pedal, the engine will stop, and the car will eventually come to a stop. A gasoline-powered engine brake works differently than a diesel-powered engine brake. We are going to discuss these methods. So read along!

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How does engine braking work?

How does engine braking work?

The engine braking method works when you stop accelerating your car; the air intake valve closes, and it creates a vacuum inside which prevents the pistons from moving, and gradually the engine loses power, and then the car runs only by wheel force, which eventually slows down too. There are two types of engine brakes based on the size of your vehicle. They are:

gasoline engine

In a gasoline engine, the engine braking system works when you stop accelerating, the air intake valve gets closed, and thus the airflow into the engine gets restricted, creating a high vacuum in the engine’s intake manifold.

This vacuum makes it harder for the engine’s cylinders to work, slowing the car down by working against the vacuum. While some of the braking force is due to friction in the car’s parts, like friction in the body and tires, but most of it is caused by the vacuum created by the lack of air, which makes the vehicle lose momentum and slow down.

diesel engine

A diesel engine works differently than a gasoline engine. Diesel engines don’t have air intake valves, making it challenging to slow down. Creating a vacuum inside the engine chamber needs a different method since the diesel engine doesn’t have an air intake.

Modern diesel vehicles use an exhaust brake that restricts the flow of exhaust gases through the exhaust pipe, creating pressure in the cylinders and slowing down the engine. Many vehicles use a butterfly valve for this procedure, while others use a variable-vane turbo valve to stop exhaust gas from escaping.

However, engine braking on diesel engines only works when the car is in gear. If the clutch is released, the speed reduction force won’t transfer to the drivetrain, and the wheels will keep moving at the same speed. If you have a standard automatic transmission system on your car, engine braking might not be something you can do very often. 

You can still do it by switching from driving to a lower gear. This will help slow down your car when you take your foot off the gas pedal. Also, Some automatic cars let you change gears using a lever or paddle shifter, so you can downshift to slow down.

It’s important to note that you should only shift to lower gear before going down a hill or mountain, not while you’re driving at high speeds. The higher the RPM, the stronger the braking force, making it easier to slow down the vehicle. 

Jake brake

Jake brake is a specialized engine braking system made by Jacobs vehicle systems in 1965. The “Jake” nickname comes from Jacobs Engine Brake. Due to many heavy load, many oversized vehicles, like buses and trucks, work on diesel engines. Big vehicles are often equipped with Jake brakes.

This unique technology is used in diesel trucks to help slow them down using the engine. Usually, when the engine works, it takes in air and gas, compresses them, ignites them, and pushes the vehicle forward. But with jake brake, things work a little differently. Instead of igniting the gas, the engine opens a valve to release the compressed air out of the engine. This means there’s less energy to move the vehicle, so it slows down the vehicle more quickly.

For example, When a big rig truck runs, the air goes into the engine cylinders and gets compressed to create energy. This energy is used to power the vehicle through the pistons. But when the driver uses the Jake Brake, the compressed air is released out of the exhaust valves instead of being used to power the vehicle. This creates resistance on the engine and slows down the truck without using the brakes, helping preserve the brake pads.

How to engine brake

Let’s say you are driving in 5th gear, and there is a traffic stop ahead. To apply the engine brake, you need to take your foot off the accelerator and switch them into a lower gear, such as second or third gear (remember you need to rev with matching your downshift).

This will gradually stop your vehicle without stepping on the brake pedal. Then use the clutch and brake to stop the car safely. This process helps your brake pads from getting worn out and maintains them for a long time. Effectively using engine brake smoothly will take some time and practice to learn, so be on it.

You may be interested to read About What Depressing Brake Pedal Means.

Benefits of engine brake system

Benefits of engine brake system

There are quite a few benefits of using engine brakes frequently. Some of them are

Reduces damage(wear and tear) on your brakes.

When you drive your vehicle, you usually use brake pads to slow it down by creating friction. However, this constant use of it can wear down your brake pads and rotors over time, making them less effective eventually.

By using engine brake along with your foot brake, you can apply less pressure on the foot brake for a shorter amount of time. This especially helps when driving down long hills or mountains, where using the brakes for too long can cause them to overheat and become less effective. This is called brake fade, damaging your braking system. 

Brake fade means the brakes will fade out from too much friction and heat and eventually stop working.

Using engine brakes instead generates less heat and wear on your brakes, making them last longer and keeping you safer while driving downhill.

Increased fuel economy.

When using engine brakes, you try to stop accelerating your vehicle, which helps in stopping the engine from consuming fuel.

So frequently using it can save you a bit of fuel which comes in handy, especially on long trips.

Doesn’t damages the vehicle, as the foot brake does

There’s a myth that engine braking is terrible for your car, but it’s not true if you do it safely. When you try engine braking for the first time, the engine may sound loud, but that’s normal and won’t harm your vehicle. Engines can handle a lot of power and heat since they run at thousands of revolutions per minute for long hours during road trips. Your car should be perfectly safe if the RPMs aren’t near or above the red line on your dash gauge.

Engine Braking TIPs

The most significant danger of using engine braking is the possibility of damaging your transmission. However, you can prevent this by following some easy driving tips:

  • Avoid shifting to a lower gear when driving at high speeds, as it can be uncomfortable for your passengers and put unnecessary strain on your engine and transmission.
  • When downshifting, shift down one gear at a time and wait for your vehicle to adjust before shifting again.
  • Be careful not to rely too heavily on engine braking, especially if you have an automatic transmission. Overusing it can cause damage over time.

Where You should use Engine Brake

Because of the noise they generate, engine brake use is best limited to typical situations, including:

  • Long, steep downgrades – Prevents overheating and fading of the service brakes, which could lead to losing control.
  • Stop-and-go traffic jams – Reduces wear on friction brakes in blockage requiring continual braking.
  • Approaching toll booths or work zones – Its Best to be at a safe speed before stopping on the construction hazards.
  • Entrance and exit ramps – For smooth blend into faster traffic flow.
  • Mountain driving – The added braking capacity helps maintain proper descent speeds and control on high grades.
  • Slippery road conditions – Improves braking ability and control on wet, icy or snowy roads where wheel brakes can lock up.

Pro Tip: Avoid excess engine braking in residential areas and light traffic situations. The loud exhaust noise can disturb neighbourhoods and other drivers.

Conclusion

The answer to the question, What is an engine brake? It is really simple if you put your mind to it.

After reading the article, you may have understood that An engine braking system basically means slowing down your vehicle without using foot brakes. Meaning that by stopping accelerating your vehicle, the engine loses power and eventually stops. Engine braking improves safety inside the vehicle and reduces brake fade.

But there are myths that engine braking is terrible for your engine, which is not valid. If done correctly, the engine brake helps your vehicle to minimize the damage done to brakes and increases fuel economy. Making the brake pads stress less is necessary and should be done regularly to maintain the brake pad’s longevity and have a safe braking system for years to come.

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