[Vwdiesel] Turbo in series or parallel

[Lee Hillsgrove]

> > The GMC two strokes use the supercharger for scavenging, not boost.
> > BIIIIIG difference.
> >
>
>   I thought it was because there's no intake stroke to draw air into the
> combustion chamber?  2 cycle motorcycles use the crankcase as a
> "pressure chamber and the downstroke of the piston to pressurize it.
> That would be more leak prone in an automotive/industrial engine so
> a supercharger is used.  A turbo would do no good for starting.
>   Am I wrong?


 Not really. I think they gear the blowers on Detroits to supply about what
the engine consumes, and maybe a tad more. Force-feed the inlet of the
blower with a turbo or two, and you get net boost. When the piston is almost
at BDC, all of the valves in the head open up and the pressurized exhaust
flows out, aided by the positive scavenge air flowing in on top of the
piston through the transfer port in the side of the cylinder. No real
pressure until the exhaust valves close. At this point the intake air
pressurizes the cylinder until the rising piston covers up the transfer
port. Since there is more air than what would have flowed in on it's own,
there will be higher cylinder pressures, mostly as a result of having more
air to allow more fuel to be injected.

 Sound about right?

 You *need* to build one of the Deutchland Diesels we have talked about,
Loren. :-))

  Lee
  Oo-v-oO
  PP-ASEL
  KB1GNI