Electric motor assisted super- or turbocharger?

Yup, yer right. Just checked. Must be confusing the DH with another engine.

"Heywood" wrote in message
ups.com...
Nope, the Deltahawk uses a traditional Roots belt-driven blower for
starting and low-rpm operation.

This actually makes sense. Electric motors have become much more powerful
for their weight. In the case of a two stroke diesel, electric boost would
only be used to get the engine running on the turbocharger. Thereafter,
it's unlikely to be needed except for an emergency air-start. Since the
power of the exhaust turbine exceeds what is needed for the compressor at
cruise power, the electric motor could become a generator. This rig is
likely to be simpler and lighter than a blower/turbocharger in series.

Bill Daniels

"Max Kallio" wrote in message
om...
2-stroke diesels need compressed air for starting the engine, so the
turbo (exhaust driven centrifugal supercharger) is out of a guestion
and it produces very little boost at low rpm anyhow.

How about supplementing a centrifugal turbocharger with a high speed
electric motor to create boost needed for starting and to enhance
boost at low rpm?

This would pretty much eliminate the turbo lag and actually help suck
the exhaust out of the cylinder at low rpm.

When the rpm rises, the electric motor could disengage or perhaps even
work as an auxilary generator.

Also, if the turbo has some problems, the electric motor could be used
at full power to help the turbo to spin and create boost at least for
the time it takes to land safely. Of course, the engine should be
able to have enough power to stay airborne at least at low altitudes
(if the load is not exeeded) even when the turbo fails completely.

Links...

www.turbodyne.com

Max Kallio wrote:
2-stroke diesels need compressed air for starting the engine, so the
turbo (exhaust driven centrifugal supercharger) is out of a guestion
and it produces very little boost at low rpm anyhow.

Why do two-stroke airplane diesels need compressed air for starting?
The Detriot two-stroke diesels used in trucks and off-road equipment
have never needed that.


Matt

Max Kallio wrote:
2-stroke diesels need compressed air for starting the engine, so the
turbo (exhaust driven centrifugal supercharger) is out of a guestion
and it produces very little boost at low rpm anyhow.

Modern large 2-stroke Diesels (EMD 710 series for example) have a
mechanical drive to the turbocharger which spins it at low power
settings and it acts as a mechanical blower. As power settings come up
and exhaust volume increases, the turbine takes over and operates the
supercharger. Much more efficient than converting mechanical power to
electrical then back to mechanical again.