Posted: 9/16/2012 7:23:04 AM EDT
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Please explain multi-fuel vehicles to me (not flex fuel)-
I guess the only ones out there are mil-spec vehicles, but (1)do they require any specific proportions or mix of diesel/kerosene/gas, or will they "run on anything" with no harm even if the engine is sluggish or hard to start? Also, (2) are there any modern commercially available vehicles out there that are true multi-fuel, or is one limited to diesels running on various strained waste oils, cooking oils, etc.? FWIW, I googled it and got some mundane answers and figured this would be the best place to ask; even went to Steel Soldiers and that seems to devolved quickly... |
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Tag for an answer.
I can see how an engine could run on kero, diesel, aviation fuel, as they are pretty much the same thing. However, do they make engines that run on these as well as gas? Then you need an ignition system and spark plugs. How do you keep them from getting fouled when you use diesel? What kind of compression do you run to use both? |
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You really need to get an OLD direct-mechanically-injected diesel engine for this.
My UNIMOG will run on strained goat piss but it doesn't have sensors, electronic injectors, glowpugs, or anything ...except a piston going up and down, two valves, and a simple mechanical injection pump. The only neccesary electrical component on the engine is the actual starter motor. Once the engine is running I could disconnect the batteries and throw them away... I find anything over a 50/50 mix of waste motor oil-to-diesel fuel makes the engine smokie. This is greatly improved by throwing a couple gallons of gasoline in there to increase volitility a bit. Find something old and simple and play with it. You might learn something BEFORE you need it, and it will probably make you a better mechanic in the process -not a bad thing in-and-of itself. 
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I found a link which explains it.
The have very high compression ?22:1 or 27:1? It has a unique piston design with a cup in the top. It sprays fuel into this cup. There is no ignition system. This cup compresses the mixture to the point where it serves as the "spark" which ignites gasoline. Very interesting stuff. |
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Quoted:They have very high compression ?22:1 or 27:1? It has a unique piston design with a cup in the top. It sprays fuel into this cup. There is no ignition system. This cup compresses the mixture to the point where it serves as the "spark" which ignites gasoline. Very interesting stuff.
The compression doesn't need to be nearly that high. The comp ratio for my OM352 engine is just 17:1 Here is how compression ignition works: Take 70° air and squeeze it into half the space: it's now 140° air. At 4:1 it's 280° 8:1 it's 560° You squeeze the air until it's contained heat energy is in a small space. That brings the "temperature" (heat energy per volume) up! ...to a temperature which will ignite the fuel you're using. |
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the old duece and a halfs could adjust somewhat and you can read on steel soldiers about that a bit. Even then it can only adjust so much. Those are some of the better diesels I have read about with an actual multi fuel engine and made to run a mix. For gassers it just takes low compression and adjustable timing and knowing how to make it work. I don't know if anyone made one that was mostly automatic at adjusting for cruddy fuel but overall some of the 70s v8s can run on junk gas that some of the more modern cars are not always very happy with. but todays vehicles will adjust themselves. |
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Back in about 1985 when I was running a diesel fuel injection shop, we had a multifuel injection pump come in for repair. I understood it to be off of a tank out at the National Guard, but could have been wrong. At that point I had been schooled all over the country on all brands of diesel fuel injection equipment. That injection pump had stuff hanging off of it that I had never seen or even heard of. We ended up sending it off to a facility that was certified to work on them.
Edited for spelling... |