Ed Huntress wrote:
"RoyJ" wrote in message
...

After reading the other comments I think you have multiple issues going on
to switch from diesel to gasoline:
-the gasoline will have a MUCH lower viscosity, you are going to get way
different (more)amounts of fuel through the injector. I'd think that is
what causes the white smoke a lousy performance, it's too rich.
-at the same time, gasoline has lower fuel value per gallon or milliliter,
same volume of fuel will cause the engine to go lean, never a good thing


You raise an intriguing question there, Roy. How do you make a diesel run
lean? g


-gasoline has a much higher flame front speed, ie it will detonate, really
does bad things to the top of the piston.


It will detonate, but it's because of the *slower* flame front speed. That's
the thing that's indirectly measured by the cetane rating: gasoline around
25, diesel typically 45+.


Ed,

I'm wondering if some of the problem here is with the nature of the
combustion in the 2 engines. My understanding is that the SI engine
burns a vapourised fuel air mix which burns like any gaseous fuel air
mix but in the diesel combustion the fuel droplets burn at the surface
of the droplet in the combustion air, the lighter fractions burning
first leaving the heavier fractions, hence the particulates left behind.
The modern diesels in small vehicles, at least in Europe as I think
regulations have constrained small diesels in the US, have much finer
atomisation of the fuel due to the high pressures used which allows
shorter burn times and higher resultant RPM but the nature of the
combustion still differs from that of a petrol engine.

-gasoline has no lubricating qualities, will tear up a standard injector
pump in short order.

Very interesting discussion. I've been asked to be the project manager for
an alternate fuels project based around a 100kw Cat diesel generator. Fire
up on a new fuel, check for short term issues, go to a 50% load then 100%
load for 8 to 24 hours, then tear down and look for damage. Looks like I
would be spending more time than planned dealing with the injector pump.
Hmmmmmmmmmmmmm.

Ivan Vegvary wrote:

Sorry about the OT, but, I do contribute once in a while and this is such
a knowledgeable group!

Many decades ago (1950's) when people talked about diesel engines (lot of
this talk was from 'old country' poor Europeans), they would always tout
the fact that they (the engines) would run on anything. The list, if I
remember correctly included diesel, gas, lighter fluid, heating oil,
liquefied lard, charcoal lighter, veggie oil etc., etc., etc.

If any of the above is true, why don't people, today, put gasoline into
their diesel engines, considering the higher cost of diesel fuel?

Just want to know what would happened if you did use gasoline.
BTW, my only diesel is my small Kubota tractor.

Thanks for replies.

Ivan Vegvary