In <list-1322082@skylee.com>, on 10/05/01
at 03:19 AM, "Richard Notton" <Richard@fv623.demon.co.uk> said:
>Its simpler than you think, just a butterfly valve in the exhaust
>manifold usually operated by an air cylinder from the vehicle brake
>supply.
But that is not going to actually release the cylinder pressure to the
atmosphere. Thus the following downstroke will simply rebound the energy
stored up during compression and you gain zero 'engine braking', save for
friction losses.
Now, if you added a throttle/choke plate to the intake, as in a gasoline
engine, you can very simply derive the same measure of 'engine braking'
that a gas engine offers. Which is not inconsiderable. Plus it would serve
as an emergency anti-runaway device should the injection pump ever fail.
Nice to have if you go down steep mountain roads.
The Jake brake system must, somehow, kick open the exhaust valve BTDC to
release the compression and then immediately close it, to create suction
on the 'power' stroke. Alternatively, a poppet valve could be added to the
combustion chamber and, timed accordingly, offer the same effect.
>Richard
>Southampton - England
Bill
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