multi-fuel deuce diesels?

[warwick]

can someone give an explanation of how or why they able to run on multi-fuels? also what componants of the engine make this posible and do you have to "adjust" anything on the engine when runnig fuel other than diesel?

any internet resources with an explanation?

also what fuels would/do they run on?

 

[jld66]

The multifuel engine will burn most common internal combustion engine fuels, i.e. diesel, gas, jet fuel, kerosene, etc. The operator does not have to do anything to adust the engine when using different fuels. There is a fuel density compensator built into the injector pump that adjusts automatically. Note that some (many?) of these engines have had the compensator bypassed during depot rebuild or other repair operations. This can be reversed. I;m sure someone else on the board can explain how. This was done because the engines really prefer deisel and run more efficiently (better milage) with the compensator bypassed.

There should be a dataplate on the dash with allowable fuels.

Ther is also good information in the "dash 10" operator's manual on preferred fuels and fuels that should not be used. The more highly volitile fuels, though they work well will shorten engine life.

 

[Trango]

All diesels are compression ignition engines, using the heat and pressure of compression to ignite the fuel/air mixture.

The Multifuel is another compression ignition engine, that uses (as I understand) viscosity of the fuel as an indicator of how to adjust the Fuel Air mixture to compensate for the possibility that a lighter fuel, like gasoline, may be used in place of diesel.

You could make a compression ignition engine out of any gasoline engine - just either let carbon build up on the valves and make a heat riser, or run gas of too low an octane, or even too lean - all of these will cause "knocking" or "pinging", nicknames for predetonation, which is, essentially, dieseling.

Cheers
Bob

 

[Monster Man]

the compression ignition engine uses pressure to heat the air in the cylinder, and at the precise moment of the most heat/pressure, diesel fuel is injected and it explodes, without the aid of a spark. Some diesels use glow plugs that are provide a heat source so to speak and help to ignite the mixture when cold, but don't do any good when it's hot. Multifuels don't have no stinking glow plugs! (But are hard to start when cold, sometimes VERY hard)
it's always best to mix these other fuels with diesel for the best running

 

[jld66]

The multifuels don't have glow plugs, which preheat incomming air only in a cold engine (as in the CUCV series) but they do have a "manifold heater" for cold starts in cold weather. Look to the lower left of the dash in most Dueces and you will see the preheater switch. This switch should ONLY be used while cranking a cold engine in cold weather. This sprays fuel into the intake manifold and ignites it with a spark plug, thus heating the incoming air. The problem with this is that although it heats the air to make starting easier, it also burns much of the oxygen out of the air which does just the opposite.

BTW, the multifuel engines were liscensed for manufacture in the U.S. from a German company.

 

[ken]

These engines also have a sphere shape in the top of the pistons. So that lighter fuels gasoline, naptha, etc. will puddle in the piston. As the piston travels down on the power stroke the puddle of fuel is sopposed to vaporize and burn. I have this prosess in a TM somewhere, I'll have to dig it up. This works with the fuel density compensator to prevent preignition. I currently burn about 20% used motor oil to diesel with great results. I've used gasoline in a emergency, The truck ran fine but lost a lot of power and milage was cut almost in half.

 

[cranetruck]

I have found that the flame heaters work poorly on turbo engines. The intake manifold adapter is much narrower than the one on the naturally aspirated ones. The increased speed of the air snuffs out the flame (made a monitoring device for this). The spark plug actually generates a continues series of sparks from a vibrator, but is still to weak to keep the fuel ignited. Cold diesel fuel is difficult to ignite.

You are right about the air being used up in the process, but at low rpm there is lots more available than needed for combustion.
About cold starting, with a good set of batteries and a fast cranking engine it will start without any starting aids down to about 0 to 10 degrees F.

The fuel density compensator compares the specific gravity of the fuel to diesel and increases the amount of fuel if a less dense fuel is detected. All it does is keeps the power output of the engine constant for a given position of the "gas" pedal. By-passing it provides a little more fuel to the engine for the same given position of the gas pedal. You can still burn other fuels, but the performnce of the engine will suffer some.
I rather keep the compensator in the circuit, if more fuel delivery is desired, the governor can be adjusted.
All diesel engines can burn a multitude of fuels, from cooking oil to kerosene, but the deuce engine has a specially designed piston ( a cavity in the top) that helps atomize the fuels better. I think this is where the license from MAN in Germany comes in.

I have used biodiesel and cooking oil in my truck ranging from 10 to 90% and has found that the engine runs very well on any of it, but diesel does give it a little more boost. Put over one thousand miles on it since April of this year with biodiesel, cooking oil and petro diesel in various combinations.
BTW, the biodiesel is home made and may contain some methanol too.

I'm aware that these subjects have been covered before in many places on this forum, but they also get buried easily. I apologize to you guys who may be getting annoyed by reading the same stuff over and over.

 

[warwick]

I apologize to you guys who may be getting annoyed by reading the same stuff over and over.

i to am sorry if this topic has been covered before, i have trouble with the search feuture on many forums and i am new to steelsoldiers. should have spent some time in the archives but this has buged me for awhile.


anyway i guess it depends on the cetane number of the fuel and the compression of the engine. i am interested in the fuel density compensator(FDC) and how it works, ie how it determines the specific gravity of the fuel and how it adjust to compensate.



just thinking out load but i was interested in the cucv 6.2 diesel and how someone could make it a multi-fuel diesel. after reading the responses it appears the engine is already a mult-fuel diesel and the lack of the concave piston and FDC are what seperates it from the duece engine.



also are the internals of the duece engine designed for multi-fuel use, ie metal used ,gaskets and rubber etc.?

 

[cranetruck]

Quote from Ken:
"As the piston travels down on the power stroke the puddle of fuel is sopposed to vaporize and burn. I have this prosess in a TM somewhere, I'll have to dig it up."

I have never seen this explained and would be interested to know how it is supposed to work. Let me (us) know if you find the reference.
Thanks,

 

[cranetruck]

Here is the front page of the patent for the fuel density compensator.
Go to the US Patent and Trademark Office and download the rest of it.

 

[frank8003]

Here is the front page of the patent for the fuel density compensator.
Go to the US Patent and Trademark Office and download the rest of it.

Yep, that is gone from the post, I was looking for that.

 

[wiersema07]

What’s the mixture ratio you use with used motor oil . Does it mix with diesel and does it have to be the engine oil of truck or can I use the motor oil I have left over from my cars ? Thanks

 

[gimpyrobb]

Any oil, any ratio. Ive run 100% used motor oil. It didnt like starting when the temps were below 20* though.

 

[wiersema07]

I guess I’m just scared since I’ve never owned one to just dump motor oil in it lol. I have at least 40 gallons of used oil in garage. Does the truck run differently if using oil. Or smoke more? I have about 1/4 tank of diesel in it now.

 

[gimpyrobb]

Honestly, you need to filter it first. I usually mix gas or diesel in the oil, then pump it through filters into the tank.

We have an "alt fuels" section you should read through prior to experimenting.

 

[98G]

I guess I’m just scared since I’ve never owned one to just dump motor oil in it lol. I have at least 40 gallons of used oil in garage. Does the truck run differently if using oil. Or smoke more? I have about 1/4 tank of diesel in it now.

Ideally you want to centrifuge it. My understanding is that some of the abrasives that accumulate are too small for effective filtration.

 

[rustystud]

Ideally you want to centrifuge it. My understanding is that some of the abrasives that accumulate are too small for effective filtration.

That is totally correct. The used oil will have millions of "micro-particles" that will actually destroy the injection pump. Think micro sand-blasting. Using a centrifuge is the "only" right and economical way I have ever heard that will clean-up the used oil for use with injectors and an injection pump. Just so you know, Bosch said to use a 2 micron filter for the final oil filter on this injection pump. And that was with using "clean" diesel fuel !
I know Gimp has used it in his truck with "apparently" no harm, but I would not chance it.

 

[gimpyrobb]

Mehhh

I ran only filtered used oil for many years. When I did my headgaskets the injectors were worn out but the IP still worked. The money I saved could have paid for LOTS of injection pumps (and did).

Sure, you can play it safe and spend big bucks on a "fuge" but then, your spending big bucks. Might as well spend it on the IP.

 

[73m819]

The Gimp is the ONLY person that I know of that makes used waste oil CLEANER then pump fuel.

 

[Flyingvan911]

I hear you have to filter it sideways.