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Old 6th April 2008, 12:12   #1
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Default Retarder in Volvo B7R buses (air-brakes / jake brakes)

Hi,
when i was travelling in the B7R volvo i have noticed a lever which controls the 'retarder level'
was wondering what this retarder is.

this thread
http://www.team-bhp.com/forum/indian...k-again-3.html

talks about a Voith hydraulic retarder.

anybody know how this works ?

-SF
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Old 6th April 2008, 12:29   #2
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such heavy vehicle and trucks has engine brakes in addition to ususal brakes.
this retarder level controls the level of this brake.
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Old 6th April 2008, 15:54   #3
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Quote:
Originally Posted by SirAlec View Post
such heavy vehicle and trucks has engine brakes in addition to ususal brakes.
this retarder level controls the level of this brake.
Thanks SirAlec, but i was curious to know where excally does this brakeing take place.
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Old 6th April 2008, 16:17   #4
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its a non-friction type brake, depends upon vehicle to vehicle. you can learn more from

Engine braking - Wikipedia, the free encyclopedia
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Old 7th April 2008, 23:25   #5
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There are retarders, engine exhaust brakes etc.

Retarders

Exhaust brake - Wikipedia, the free encyclopedia
Banks Power – Exhaust Brake Systems: Why Add an Exhaust Brake to turbo diesel powered vehicles for supplemental engine exhaust braking.

Tata and Leyland also has the exhaust brake from CD TVS.
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Old 26th April 2008, 09:40   #6
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And now, KSRTC's long distance Leylands are also sporting Voith Retarders. This seems to add one more feather to Karnataka's ST service ..
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Old 26th April 2008, 10:25   #7
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Default "Jake"

The most famous retarder is the Jacobs brake or "Jake brake". The idea is to recycle or restrict exhaust gas in such a way as to use the engine as a brake. On heavy vehicles this is a great benefit when going down a steep hill as it greatly assists the normal brakes on the wheels and prolongs their life. It is a great little safety feature on big vehicles and some rather clever "keep it simple stupid" or KISS method engineering.
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Old 27th April 2008, 23:47   #8
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Ah, thats the name! I remember my Dad mentioning this a very long time ago, and I also remember this being used on our school bus during a tour(I quizzed the driver as to the peculiar sounds coming from the engine while descending the ghats
).
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Old 8th July 2008, 16:10   #9
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To add on...retarders are auxillary brake systems that minimises the utilisation of Service Brakes.It forms part of the brake blending process.
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Old 8th July 2008, 23:03   #10
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Like mentioned by others, it is an exhaust brake. This basically restricts the exhaust and uses the diesel engine compression to brake the rig. Really helps for gradual stops by saving the brakes from heating up.

This is standard for most big rig trucks.
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Old 8th July 2008, 23:34   #11
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A query:

1)
Does this mean that the engine braking is increased ( by increasing the back pressure on engine ) by restricting the exhaust flow ?

2)
Wont this affect the performance of turbocharger ? Does this also affect the life of turbocharger ?
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Old 11th July 2008, 14:18   #12
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Quote:
Originally Posted by aaggoswami View Post
A query:

1)
Does this mean that the engine braking is increased ( by increasing the back pressure on engine ) by restricting the exhaust flow ?

2)
Wont this affect the performance of turbocharger ? Does this also affect the life of turbocharger ?
1) Yes, thats what an exhaust brake does. However, IIRC, a retarder acts on the driveshaft.

2) IMO, Engine exhaust brakes do not affect turbocharger performance / life.

To add on, engine compression brakes ( valve brakes) add on to braking power of exhaust brakes.


Cheers
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Old 30th March 2010, 00:55   #13
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Voith is a hydrodynamic retarder. It uses oil to create a turbulence inside a rotor -stator mechanism and this slows the rotor connected to the engine shaft.
Voith Turbo - Retarders - Functionality of the Retarder
The link above explains how it works.
Voith and jake brakes operate on different principles.
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