Engine Brake Operation?

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Motogary
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Engine Brake Operation?

#1 Post by Motogary » 26 Mar 2017 20:51

Can someone explain how the engine brake operation is supposed to work?
Motogary
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Joined: 07 Dec 2016 01:39

Re: Engine Brake Operation?

#2 Post by Motogary » 26 Mar 2017 21:21

And what is the difference between that and the retarder?
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natvander
SCS Software
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Re: Engine Brake Operation?

#3 Post by natvander » 26 Mar 2017 22:31

It's an auxilliary brake to take load off the service brakes. When you want to slow down, you use the engine brakes first and use the service brakes only if/when required. In game engine brakes have three levels of power.

You can have a toggle button for the engine brake so they activate when your foot is off the accelerator, and/or a button you need to hold down for their application.
Never argue with idiots. They bring you down to their level and beat you with experience.
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EricF
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Re: Engine Brake Operation?

#4 Post by EricF » 28 Mar 2017 00:00

To add a little more detail, the engine brake is either a compression release type (Jacobs or "Jake Brake") that acts on the exhaust valves to make the engine work against compressing more air, or an exhaust brake ("Pac-Brake") that restricts the exhaust outlet to create back-pressure and more resistance. The "Jake Brake" is particularly noisy and use is banned locally in some places; the exhaust brake is generally not much noisier than normal exhaust but doesn't develop as aggressive a braking force.

The retarder is usually a hydraulic device attached to the transmission output shaft which adds resistance through a movable vane assembly running in hydraulic fluid to create resistance. There are also electric retarders which use a motor-generator assembly to create resistance. Both retarder types resist mechanical energy and convert it into heat to slow the truck down. This is what the service brakes do with mechanical friction -- but retarders can run for far greater distances (think long mountain down-grades) with less chance of overheating and losing effectiveness. They're also quieter than engine/exhaust brakes. However, they have to be used appropriately to avoid overheating. Electric retarders also put a heavy electrical load on the truck's alternator -- so it has to be sized (and possibly upgraded) appropriately.

Engine brakes and retarders lose effectiveness at lower road and engine speeds -- the truck has to be in the right gear (lower, to increase engine RPM) to get the most out of an engine or exhaust brake, and retarders are less effective as road speed decreases.
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wolfedg
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Re: Engine Brake Operation?

#5 Post by wolfedg » 22 May 2017 14:32

Thanks to everyone who responded as I was curious as well. I would like to add to this another question.
I have been trying to use the "brake ari pressure" feature in the game by using the engine brake and retarder, but I still keep running out of air when doing trailer parking. I'm guessing this has to do with my using keyboard to brake as it is either 100% on or 100% off. Can anyone confirm this?
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BK Vissers
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Re: Engine Brake Operation?

#6 Post by BK Vissers » 22 May 2017 14:52

I use the keyboard as well. I had this problem early on but as I practiced parking more it would happen considerably less often. So air brake simulation "on" is quite doable with keyboard control, but yes, you're going to use air more quickly than if you could apply less than full brakes. :)
stb155
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Re: Engine Brake Operation?

#7 Post by stb155 » 29 May 2017 20:18

IMHO it does not work accurate in ETS2.

In modern trucks you have one stalk right of the steering wheel that controls "auxiliary brakes".
This is either just engine/exhaust brake or engine/exhaust brake+retarder, if truck is equipped with retarder.
(and on highest setting it also makes the automated gearbox shift down as much as possible for best engine brake)

In ETS2 you always have to control them separately, and annoyingly using either one cancels the engine cruise control, which it should not do.


If you use the regular foot brake (which you AVOID as much as possible IRL), the auxiliary brakes get mixed in automatically.
This also works in ETS2, if you set them both to automatic in gameplay settings.
(IMHO it is exaggerated though, tiny tap on the brake makes gearbox shift down 3 gears for max engine brake)
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