K. Smith wrote:
zee-qi wrote:
hi people.
i would ask you something.Who can explain me how does work diesel
engine.?and what kind of system it need to work normally.
..thx for your ansver...


They use diesel fuel which has a very low auto ignition temp (about
200-210C) so if a "vapour" of diesel sees 200C it auto ignites without a
spark.

Petrol gasolene has a higher auto ignition temp (250-280C) so it needs
an electric spark to ignite it.


Are you sure you're explaining that correctly?

Wouldn't research into the temperature of the air charge in a
compressed diesel cylinder show that it is more than hot enough to
ignite gasoline? In fact, putting gasoline into a diesel engine can
destroy the engine because the gasoline is more volatile than diesel
fuel and tends to "explode" rather than burn in the cylinder. That's
always been one of the reasons that gasoline engines have compression
ratios of just about half a typical diesel, and that traditionally
gasoline has had to be doctored with "octane boosters" to burn more
evenly with the lower compression. Gasoline can "pre-ignite" (fire
without a spark) in a gasoline engine cylinder with a 10:1 compression
rating
so wouldn't it be reasonable to conclude it would be even more likely
to ignite
in the higher temperatures developed by about 20:1 compression.

In extremely cold weather, some diesel engine operators will mix small
amounts of gasoline with the diesel fuel in order to make the fuel more
combustible in a diesel engine. In that case, it's the gasoline that is
helping the diesel burn, not a case of more easily ignited diesel
assisting the more reluctant gasoline to burn as a result of
compression.

Maybe I'm reading your statement incorrectly, but if not there's a
chance you might want to clarify it a bit.