Fuel injection plugs

[James Ballenger]

steve ravet wrote:

> > This can't be right, "If the volume of a system (such as a gas) is held constant,
> > that system can do no work."  That being said, a constant volume reaction would do
> > no net work.
>
> The spark engine burns it's fuel much faster than the diesel engine.  It
> burns fast enough that it's simplified to a constant volume compression
> because it burns while the size of the combustion chamber is not
> changing size that much (right around TDC).  The volume then changes of
> course, when the piston moves down under the pressure of the hot burned
> mixture.  That's where the work comes from.  The whole cycle isn't
> constant volume, just the part where the heat is added.
>
> The diesel engine injects and burns fuel during the whole power stroke.
> While the fuel is burning and trying to raise pressure, the piston is
> moving down and releasing pressure.  It's modeled as a constant pressure
> expansion.
>
> --steve

Thanks steve, a very good explanation that made sense.  It seems that, technically, the
work is still governed by the compression ratio because work is still dependant on the
increase in volume.  Though technically, I can push against a 2 ton rock all day long
and accomplish no work though I would be damned tired.

James Ballenger