Gas in a diesel engine. - PeachParts Mercedes-Benz Forum

Goowrangler · #1 02-13-2006, 04:22 PM

why can't you put gas into a diesel engine?

What is the exact definition as to why you shouldn't?

from what i think and your guys ideas of makeing Biodiesel and that other kind that you actaull mix gass with to kind of refine it why not use starigh gas.

don't worrie i am not going to do that to my engine. i am curious and no one can give a good straight answer.

Don' think i am an idiot i just thought that if ya'll are refining grease to go into the engines why not use dsomething that is refined even more then diesel itself

please help me understand.

~kb

TheDon · #2 02-13-2006, 04:25 PM

diesel engines are compression engines while gas engines are spark ignition engines. last time i checked gas doesnt combust under compression like diesel fuel. something like that

MS Fowler · #3 02-13-2006, 04:27 PM

Gasoline burns too quickly. Combustion would begin while fuel was being injected.

ConnClark · #4 02-13-2006, 04:32 PM

The only reason I know for sure of is gas has a lower BTU rating and doesn't generate as much power as diesel. Anti knock compounds might also cause trouble.

pawoSD · #5 02-13-2006, 04:34 PM

Gas is way more explosive than diesel is, its a solvent. Diesel is an oil (thats why it doesn't evaporate). Diesels are high compression in order to explode the diesel fuel, between 18:1 and 24:1 usually, the MB's are around 22.5:1

Gas engines are between 11:1 and 8.5:1 in compression usually, they use the spark plug to explode the fuel.

Gas is also not a lubricant, so not only does it destroy the engine, it will ruin the injection pump as well.

Conclusion: Use diesel in a diesel.

Goowrangler · #6 02-13-2006, 05:02 PM

Another thing that i wanted to know is why don't diesels overheat like gas engines?

rg2098 · #7 02-13-2006, 05:10 PM

Quote:

Originally Posted by Goowrangler

Another thing that i wanted to know is why don't diesels overheat like gas engines?

Oh they can. But diesels have an unregulated flow of air coming into the combustion chamber which can have a cooling effect compared to a gas engine which severely limits the amount of "cold" air.

TX76513 · #8 02-13-2006, 05:11 PM

Quote:

Originally Posted by Goowrangler

Another thing that i wanted to know is why don't diesels overheat like gas engines?

Who told you that

TheDon · #9 02-13-2006, 05:12 PM

Quote:

Originally Posted by Goowrangler

Another thing that i wanted to know is why don't diesels overheat like gas engines?

everything overheats its just a matter of when

rg2098 · #10 02-13-2006, 05:13 PM

Quote:

Originally Posted by Goowrangler

why can't you put gas into a diesel engine?

What is the exact definition as to why you shouldn't?

from what i think and your guys ideas of makeing Biodiesel and that other kind that you actaull mix gass with to kind of refine it why not use starigh gas.

don't worrie i am not going to do that to my engine. i am curious and no one can give a good straight answer.

Don' think i am an idiot i just thought that if ya'll are refining grease to go into the engines why not use dsomething that is refined even more then diesel itself

please help me understand.

~kb

Gasoline will combust to quickly and explode as the piston is still traveling up. This basically causes the piston to hit a "wall" mid travel and be forced back down before the crank is in the right position to allow it back down.

Habanero · #11 02-13-2006, 05:15 PM

Quote:

Originally Posted by rg2098

Gasoline will combust to quickly and explode as the piston is still traveling up. This basically causes the piston to hit a "wall" mid travel and be forced back down before the crank is in the right position to allow it back down.

Exactly. Same phenomenom that happens to a slight degree when you hear a gasser knocking due to using low octane fuel or bad timing.

ConnClark · #12 02-13-2006, 05:26 PM

Quote:

Originally Posted by rg2098

Gasoline will combust to quickly and explode as the piston is still traveling up. This basically causes the piston to hit a "wall" mid travel and be forced back down before the crank is in the right position to allow it back down.

ummmm.... a diesel engine doesn't inject the fuel on the compression stroke.

rg2098 · #13 02-13-2006, 05:41 PM

Quote:

Originally Posted by ConnClark

ummmm.... a diesel engine doesn't inject the fuel on the compression stroke.

Quote:

A diesel engine takes in just air, compresses it and then injects fuel into the compressed air. The heat of the compressed air lights the fuel spontaneously.

http://auto.howstuffworks.com/diesel1.htm

TheDon · #14 02-13-2006, 05:42 PM

you can run it on used cooking oil ... ^_^

1985 300SD Sady · #15 02-13-2006, 09:21 PM

Quote:

Originally Posted by rg2098

http://auto.howstuffworks.com/diesel1.htm

Adam, I disagree with your above statement. (before this)

Im fairly sure the the fuel is injected right as the piston enters TDC. When the piston is at the top of the cylinder the temperature from compression is the highest. Right then the fuel is injected and explodes due to the temperature of compression alone.

In this way the injector firing combines the ideas of a spark plug and fuel entering the system at the same time.

Isnt that why injectors have to pop at such hight pressure? To overcome that which is in the cylinder?