"spamtrap1888" wrote in message
...
On Jun 24, 10:15 am, "Arfa Daily" wrote:
OK. So I was watching an episode of the U.S. documentary series
"Undercover
Stings" a couple of nights ago, and the camera focused briefly on a post
by
the side of the road. It had two square signs on it. The upper green one
said "Starke City Limit" which I understood, but the one below it -
white
background, black lettering, black line all around the edge, said "Engine
Braking Prohibited". What does this mean ? I understand what engine
braking
is - here in the UK at least - but does it mean something different your
side of the pond, and why would it be prohibited anywhere ?


http://www.jacobsvehiclesystems.com/...elease-brakes/

Hearing the jake brake's rowr rowr rowr (or blaaa aa aa aa aa) as big
trucks go downhill will keep you from sleeping.

Jacobs also makes exhaust brakes.


Ah-ha ! I thought that it might be something to do with trucks because with
most cars in the U.S. (at least the ones that I've driven) being auto
transmission, I couldn't imagine that there would be any way that engine
braking could easily be produced. I have heard of a Jake Brake on Ice Road
Truckers and IRT Deadliest Roads, but never really understood how it worked.
I don't recall them ever having commented about engine noise from using it,
but I guess that might not be too much of an issue in the wilds of Alaska or
Canada. In saying that though, I would have thought that it would have been
picked up on the soundtracks of those programmes if it was that loud ?

I have no idea whether there is a similar system fitted to UK trucks, but I
can't say that I've ever heard anything that sounded out of the ordinary
with a truck engine, so maybe not. I have seen signs here though at the
start of long downhill grades that tell trucks to engage a low gear, and
that was my understanding of what the term "engine braking" meant - taking
advantage of the engine's inherent compression, multiplied by the low gear
ratio, to produce an overun 'drag' to prevent the truck running away in a
manner that couldn't be readily corrected by use of the brakes, because of
brake fade, which I've also seen mentioned on IRT. Is this not the same
thing ? What is the difference / advantage of the Jake Brake over what I've
described, given that it is apparently noisy ?

Arfa