I had the impression that there WAS no "combustion front" in a diesel in the sense that there is in a spark ignition engine... rather, all the fuel combusts simultaneously as it is sprayed into the hot air in the prechamber or cylinder at the top of the compression stroke. Always assumed THIS was the characteristic diesel noise---a sharper, louder sound when combustion takes place throughout the cylinder in one event, rather than being spread over a small but significant period of time.
Alex Chamberlain '87 300D Turbo On 2/3/06, Peter Frederick <[EMAIL PROTECTED]> wrote: > > The noise is a combination of things, starting with a supersonic shock > wave at the combustion front. Fixed timing engines also suffer from > excessively early injection at idle, contributing to the noise in the > same way spark knock does. > > The high speed swirl in the prechamber breaks up the shock wave, > resulting in both better combustion and less noise -- alas, it also > reduces efficiency somewhat. > > Noisy Benz engines are usually as Marshall describes -- some carbon on > the nozzle will disrupt the spray pattern enough at idle, when very > little fuel is injected, enough to make it burn all at once rather than > smoothly. Sticky nozzles result in late or early injection (depending > on when it sticks, open or closed), again, clank. > > Diesels cannot detonate, the fuel has to be all present at once for > detonation to occur. > > Peter > > > _______________________________________ > http://www.striplin.net > For new parts see official list sponsor: http://www.buymbparts.com/ > For used parts email [EMAIL PROTECTED] > > To Unsubscribe or change delivery options go to: > http://striplin.net/mailman/listinfo/mercedes_striplin.net >
