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published: 04/10/05, 07:59
by DAN34
Are there petrol engines that operate with direct injection into the combustion chamber with a pressure close to that of traditional diesels?
published: 04/10/05, 10:31
by PITMIX
Hello,
I think that the FSI engines from Volkwagen and the HPIs from Citroën are petrol engines in direct high pressure injection like the TDI and HDI in diesel.
published: 04/10/05, 12:33
by DAN34
Do they perform better than conventional injection engines?
published: 04/10/05, 13:07
by MichelM
In terms of injection pressure, HDI, CDI, etc. diesels are over 1000 bars (up to 1500 it seems to me) instead of 120 bars for pre-chamber diesels (classic cars from the 80s and 90s). For indirect injection petrol it is in 2 to 4 bars, for direct injections it is in 110 bars (FSI) which is already a lot for petrol, but nothing to do with boom diesels common ...
And obviously the higher the pressure, the better it is sprayed and good for the yield, and the more it costs to build and repair!
Michel
published: 13/01/07, 19:30
by Philippe Schutt
I do not believe that these engines really work in diesel cycle.
Since the octane number of gasoline is very high, the compression ratio could (and should) be much higher too.
published: 14/01/07, 03:30
by Other
Hello,
If we call diesel an engine that turns on compression, we can say that there are several that fall into this category
There have been experiments with fuel injection during the compression cycle and also with ignitions on the compression with small stroke super square engines
(Example of two-stroke reduced model engines)
But we falsely call auto engines that run on diesel, diesel engine is actually engines that have a cycle closer to the combustion engine, except that the ignition is done by compression or hot spot of the cylinder head.
When we inject before the top dead center, it is no longer a diesel, a real diesel does not rotate quickly and we inject at the top and during the descending part of the piston.
this is why automotive diesel when they turn fast above 4000 rpm their efficiency decreases it becomes less and less diesel.
At equal compression a gasoline engine would have better performance than a diesel engine.
I think that we will continue to call the ignition distributor for a long time (a delco) as we will continue to call diesel for a long time anything that turns on the compression.
Andre