Demystifying Truck Retarders: How These Supplemental Brakes Work and How to Use Them

Hey trucker! Have you ever wondered what that cryptically named "retarder" control does in truck simulators like Euro Truck Simulator 2? Or maybe you‘ve heard real-life truck drivers mention tapping the retarder but were too embarrassed to ask what it is? Don‘t worry, I‘ve got you covered!

As an experienced trucker and technophile, I‘ll walk you through how retarders work, when to use them, and how they can improve safety and performance when operating a big rig. Once we dig into the details, the retarder won‘t seem so mysterious anymore!

A Quick Retarder Overview

First, let‘s get on the same page – retarders are supplemental brake systems used in heavy trucks and buses to provide extra braking power beyond the standard friction brakes. While the main brakes use brake pads squeezing brake rotors to slow the wheels, retarders act on the drivetrain or transmission to put additional braking forces on the whole vehicle.

Retarders come in a few main types:

• Engine brakes – Use engine compression to create resistance
• Exhaust brakes – Restrict exhaust flow to slow the engine
• Hydraulic retarders – Hydraulic discs squeeze the drivetrain
• Electromagnetic retarders – Magnets apply drag to the drivetrain

Now that we‘ve got the basics down, let‘s go deeper on how these work…

Engine Retarder Deep Dive

Engine retarders, sometimes called compression-release or Jake brakes, are one of the most common designs. Here‘s the clever way they work their magic:

1. The engine‘s exhaust valves are commanded to open at the compression stroke instead of the exhaust stroke. This releases the compressed air in the cylinder, eliminating the power stroke.

2. The engine consumes power compressing air that‘s then released rather than driving the truck. The compression of the air creates strong internal engine braking.

3. Adjusting valve timing modulation varies the retarder braking intensity. More compression release events per minute equals more braking force.

4. At zero fuel input, the engine acts as an air compressor, like a giant brake! Engine retarding can safely dissipate over 300 hp of braking power.

So in summary, engine brakes convert the motor into an air pump, using engine compression to create substantial braking force while avoiding wearing out the friction brakes!

Alternatives: Exhaust Brakes, Hydraulic Retarders, and EMF Retarders

Engine brakes dominate the Class 8 truck market, but other retarder designs have their own pros and cons:

• Exhaust brakes create backpressure by closing a butterfly valve in the exhaust system. This also slows the engine to provide retarding, but is less effective than engine brakes.

• Hydraulic retarders use transmission-mounted discs immersed in hydraulic fluid to squeeze against the drivetrain and slow the vehicle.

• Electromagnetic or "EMF" retarders contain electromagnets that apply magnetic resistance against a rotating drum on the drivetrain.

While not as common, these alternate retarder types have the advantage of being independent from the main engine. This allows them to work even when the engine is disengaged from the drivetrain while coasting.

Retarder History – From Locomotives to the Modern Trucking Industry

You might be surprised to learn that retarders originated in the railroad industry in the early 1900s!

Locomotive engineers sought ways to control speed on steep descents without wearing out mechanical brakes. They began implementing dynamic braking systems using electric traction motors in reverse as generators to slow trains.

Soon after, the trucking industry adopted the concept, developing engine decompressors and exhaust restrictors to help trucks maintain safe speed while descending grades. These primitive retarders improved safety long before disc brakes became standard!

In the 1950s and 60s, Jacobs Vehicle Systems pioneered the modern engine brake retarder. Their "Jake Brake" products became renowned for their distinctive loud chattering noise and retardation power. Other manufacturers like Telma and Voith soon introduced hydraulic and electromagnetic retarders.

Today, retarders are standard equipment on most heavy trucks. Modern "slow speed" engine brakes allow modulation all the way down to idle. Electronic controls integrate retarder and service brake operation for optimum stopping power and diminished wear.

Retarder Usage Tips and Techniques

Now that you‘re a retarder expert, let‘s get into some best practices for optimal day-to-day retarder usage:

• Use your retarder whenever you need moderate deceleration. Save your friction brakes for when you need to slow quickly or stop.

• Modulate your retarder intensity for smooth, stable deceleration. Modern engine brakes allow very precise control.

• Take advantage of your retarder when descending hills and grades. This prevents dangerous speed gain and saves your friction brakes from overheating.

• Allow time for your retarder to cool after prolonged use by cycling with your friction brakes. Overheated retarders rapidly lose effectiveness.

• Avoid retarder use on wet, icy, or slippery surfaces where traction is limited. Abrupt retardation can cause skidding.

• Disable your retarder when bobtailing or unloaded to prevent abrupt deceleration of the lighter vehicle.

• Have your mechanic inspect and adjust your retarder as part of your regular brake maintenance program. This ensures peak performance.

Retarder Limitations and Troubleshooting

Of course, like any complex truck system, retarders have limitations and quirks that drivers should understand:

• At low speeds below 25-30 mph, retardation force diminishes substantially. Supplement with your friction brakes.

• A worn or malfunctioning retarder may not provide full braking power. Troubleshoot any diminished performance.

• Contaminated hydraulic fluid or electrical faults can disable hydraulic or EMF retarders. Diagnose promptly.

• Over-retarding on wet or icy surfaces can cause skidding or jackknifing. Disable immediately if traction is lost.

• Excessive "Jake Brake" noise may indicate worn or maladjusted engine brake components. Have your dealer inspect.

So in summary, address any performance issues promptly, and avoid over-relying on your retarder in marginal traction conditions. Understanding correct operation will keep you rolling safely!

Let‘s Put It In Practice In Euro Truck Simulator 2!

Now that you‘ve got the book learning down, it‘s time to practice your retarder skills! Fire up Euro Truck Simulator 2, grab your favorite tricked-out big rig, and hit the virtual road.

Here‘s a quick tip sheet to become a retarder pro in ETS 2:

• Assign your retarder to an easily-reachable button or key. You‘ll be tapping it frequently.

• Accelerate to cruising speed and enable cruise control. Now modulate your retarder to maintain desired speed downhill.

• For maximum engine braking effect, manually downshift before activating your retarder. This increases compression braking.

• As your retarder heats up, you‘ll feel the effects diminish. Switch to friction braking for a bit to allow cooling.

• Disable the retarder when maneuvering at low speeds. Use your friction brakes to fully stop.

Soon you‘ll get a feel for precisely modulating retardation power for controlled descents and maximum service brake life. Nothing beats practice and experience!

Now You‘re a Retarder Expert!

We‘ve covered a ton of ground here, from the technical inner workings to real-world operational tips. You‘re now a true retarder guru!

I hope unraveling the mystery of these supplemental brake systems was helpful and makes you a safer, smarter real-world or virtual truck driver. Never hesitate to drop the hammer on that retarder when you need a little extra stopping power!

Let me know if you have any other truck tech topics you‘d like me to demystify. I love chatting shop and passing on my hard-earned truck knowledge. Safe journeys!