[Spridgets] Question - Jake Brake

[Kirk Hargreaves]

I have had this question in my head for a while and thought I would throw it
out to the list.

How does a Jake brake work?   I understand that it shuts off or controls the
output of the exhaust which causes back up pressure to slow the engine for
engine braking?

The engine would need to be firing in order for their to be exhaust to cause
back pressure?

Just something that has bothered me.  . and I could not seem to find
anything on line that would give a good breakdown of the process.

Certainly there are those on the list who have a good understanding as to
how this braking process works in big diesel rigs.

Thanks,

Kirk