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Dear
Tom
In a
standar Otto Cycle, power and speed control is attained by varying the fuel
addition. Same as the Diesel Cycle. However, to do this, because fuel is
premixed with air, one has to reduce the air also. The consequence of htis is
that the cylinder does not get a full volumetric charge, and as a consequence
the absolute compression ratio is reduced. Then, the efficiency
drops.
The
conceptually simple way to make an Otto Cycle engine efficient over a range of
loads is to vary the engine displacement, rather than keeping displacement
constant, and varying the compression ratio. One way to do this is
disable/enable cylinders in a multi cylinder engine, while keeping fuel/ flow to
the operating cylinders constant.
This
conceptual solution has ugly practicalities, but thats the only way I can see it
working.
Kindest regards,
Kevin
Chisholm
Dear Prof. Parikh and All:
While looking for new sources of
energy for the next millenium, please
consider "wasted throttle power".
1) Spark and diesel engines are both "hot air machines"
(with <= 6% fuel
thrown in to heat the air).
2) The
diesel engine does not throttle the air - only the fuel, so there are
no
"throttle losses" and the diesel burns from lean to very lean and so is
very efficient.
3) The spark ignited engine requires a close
to stoichiometric mixture, so
must throttle the mixture from near
atmospheric to very small values to
control power. The butterfly
throttle is a MAJOR waster of power.
4) Can't one of you clever
gals or guys invent a "working throttle" (like
the exhaust turbo) to
recycle some of this energy? How much energy is it to
take the
mixture from a power producing near atmospheric pressure to a power
wasting 25 inches vacuum? (Probably related to R ln (p2/p1)).
Too busy to figure it myself...
Cheers,
TOM REED
In a message dated
2/19/01 2:34:23 AM Mountain Standard Time,
A.Weststeijn@epz.nl writes:
Hi Peter,
Dr. Thomas B. Reed, President, The
Biomass Energy Foundation, 1810 Smith Rd.,
Golden, CO 80401
Email
reedtb2@cs.com; www.woodgas.com; 303 278 0558 home; 303 278 0560 Fax
Dr. Thomas B. Reed, Principal Scientist,
The Community Power
Corporation, Reedtb2@cs.com; www.gocpc.com; 303 278 0558
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