mastic wrote:
"Sport Pilot" wrote:


Here is an animated link showing the differances of the Otto and Diesel
cycles.

http://www.ulb.ac.be/sma/testcenter/...osedcycle.html

Notice the near instant burning in the example gives very nearly a
constant volume, in actual practice some compression is going on at
this time.

Also during a Diesel cycle it is hard to maintain a constant pressure,
it would actually drop off, especially near the end of the down stroke.


But both are still otto cycles.
If you think the fuel burns instantly in a spark engine remove the
exhaust manifold and run the engine, observe the flame exiting the
exhaust port.

Indeed, if it does burn "instantly", that is detonation. However, it
burns more rapidly in a SI engine than in a true Diesel cycle Diesel. In
fact, it is astonishing to me how fast one can turn even relatively
large SI engines, such as Formula 1 car engines. Is there no limit :-)