Mountain Driving with 1995 42', 42,000 lb. Blue Bird

[Gardner Yeaw]

The true 'Jake Brake' is an integral part of the engine design. It
alters the exhaust valve timing to use the exhaust stroke for
compression braking as well as the normal compression stroke. It
makes a very distinctive loud sound when the exhaust valve is opened
late. You most likely have heard it whan an 18 wheeler is behind you
on a down grade. This system provides a significant braking effect.

An exhaust brake simply blocks the exhaust pipe. Since the volume
of the exhaust pipe is significantly greater than the cylinder in
the engine, there is far less resistance to the exhaust stroke and
equally less braking effect.

A retarder is an electronic or hydraulic device that provides
resistance to the drive train. These systems generate a lot of heat
and need to be used in conjunction with the service brakes to
distribute the braking load.

Whatever system your coach has, take the time to understand how
it works and how to effectively use it. Don't assume that it will
work all by itself without your understanding.






--- In WanderlodgeForum@yahoogroups.com, "Stephen Birtles"
wrote:
>
> up to 1200 amps at 480 volts but don't do that on a curve or you
get
> to see the wrong side of the tree line
> we are limited to 500 amps on heavy curves
> you have to use a combination of train brake and dynamic on 2%or
more
> grades
>
> --- In WanderlodgeForum@yahoogroups.com, Pete Masterson
> wrote:
> >
> > The Jake Brake or Jacob Brake is a particular brand of engine
brake
> > manufactured and sold by Jacobs Vehicle Systems, Inc. While the
term
> > Jake Brake technically only describes Jake Brake brand engine
brakes,
> > it has become a genericized trademark and is often used to refer
to
> > engine brakes or compression release engine brakes in general,
> > especially on large vehicles or heavy equipment. See Wikipedia
for a
> > full entry at:
> > <http://en.wikipedia.org/wiki/Jake_brake>
> >
> > The magnetic retarder used on some earlier BBs is similar to
the
> > technology used for "dynamic braking" on diesel-electric
railroad
> > locomotives. The diesel-electric locomotive is actually a
diesel
> > generator (up to 5000 HP) that powers electric motors to drive
the
> > engine. On down grades, the motors are electrically switched to
> > become generators, and the power produced is directed to very
heavy
> > duty grids and discarded as heat. Realize that these things
produce
> > 600 amps at 600 volts and that's a _lot_ of heat! (Great for
toasting
> > marshmallows.)
> >
> > Pete Masterson
> > aeonix1@
> > '95 Blue Bird Wanderlodge WBDA 42'
> > El Sobrante, CA
> >
> >
> >
> >
> > On Jun 25, 2007, at 4:28 PM, Ron Thompson wrote:
> >
> > > My BB has an engine retarder. I have no idea what that is
> > > exactly. I assume it is using the compression of the engine
to
> > > hold back the transmission which will hold back the BB
> > >
> > > What is a Jake Brake?
> > >
> > <snip>
> >
>