----- Original Message -----
From: "Jim Newton" <jnewton@laurel.com>
To: "Military Vehicles Mailing List" <mil-veh@mil-veh.org>
Sent: Friday, October 05, 2001 5:45 AM
Subject: [MV] "Jake Brakes" Possible on an M35?
I looked up this term and found out that Jake Brakes are a mechanism
installed on the heads of a diesel engine which when engaged, allows
the cylinders to build up compression as they normally would to fire
the fuel, but just before firing, lifts the exhaust valves and
dumps the compressed air to the exhaust (the fuel flow gets turned
off when the device is engaged).
>
Most all our trucks have this and certainly all the continental ones,
coaches included, where you can expect to meet long and very steep, twisty
inclines.
Its simpler than you think, just a butterfly valve in the exhaust manifold
usually operated by an air cylinder from the vehicle brake supply. It is
the nature of a diesel injection pump governor that no fuel is injected
when the revs are higher than the demand from the "gas" pedal, when you lift
off on a diesel there is no fuel injected until the engine slows to the set
idle revs.
We also see electric retarders where a simple generator on the propshaft has
its output dissipated in a bank of (big) resistors, both systems can be
applied without causing wear or overheating on any component and are
usefully inherently anti-lock inasmuch as the braking effort is directly
related to wheel speed.
Richard
Southampton - England
This archive was generated by hypermail 2b29 : Fri Dec 07 2001 - 00:36:24 PST