Hi folks,

I am a professor at West Virginia University in the Chemistry department. We have developed a new lab where students prepare biodiesel fuel from vegetable oils. We would like to cap the laboratory experience with a test of the synthesized fuel, and I thought a good solution might be to use the fuel to power a Gas RC engine. This is a really interesting idea to the rest of my colleagues, so i wanted to seek some advice.

We don't really need the whole vehicle - I was thinking of mounting the engine to a board, perhaps driving a propeller, a wheel, or a pump. The student pair adds 5mL (or 2 mL) of their fuel to the tank and we start the engine. The speed and duration of power of the mounted part could be measured and provide a relative comparison of power, purity of fuel, efficiency of combustion, etc. A simple design might allow the combustion chamber to be rinsed out with a good solvent between each test of synthesized biodiesel, then blown dry before adding

To outfit all of our labs with 2 engines would take 16 engines total. We should probably have a few as back-ups, and they will have to be robust enough to be able to function after a good cleaning, ideally as i described above.

I am not an RC'er, but i am hopeful to become one by virtue of this project <grin>.

I hope this makes a bit of sense. I would welcome any ideas and feedback that you can provide.

Please don't spam me, but feel free to contact me at [email protected] with any ideas, and I will be checking back here.

Thanks,

Lloyd Carroll

RC diesels (compression ignition engines) typically run on a mixture of diesel fuel and ether. If you have heard the term "diesel" used with respect to RC engines, that's probably the context. These are not fuel injected engines.

Biodiesel in automotive and heavy-duty diesel engines has been pretty well documented, and there are problems.

There really aren't any true RC sized compression ignition engines that have timed in-cylinder fuel injection (which is what automotive and heavy-duty diesel engines use.)

Before you count on running a bunch of RC engines on your lab biodiesel fuel, you might want to check with your Mechanical Engineering department, and go over what it is you want to achieve.

Again, there are no box-stock RC engines that will just use your fuel. The few RC diesels available need ether added, to get the fire started, and the ether would have an effect on your results.

Best wishes,
Dave Olson

I have seen a Irvine 40 diesel engine run on bio-diesel fuel for model engines. It didn't have as much power as the kerosene variety but it did start and run easily.

Bio diesel is kind of "suspect" of being a carcigen, so be careful when exposing students to the exhaust fumes.
Like stated already, for lab purposes our model engines would not be well suited, because they lack direct fuel injection.
It would be a nice project by itself to convert an engine to get it to run with direct injection. Expect to use compression ratios in the vicinity of 25:1.  Low exhaust and scavenge timing engines should do the trick if fuel pump and injector can be made.

This should help you out:

http://www.enya-engine.com/store/ind...7b89965ed9adf9

Ken Enya sells his engines directly all over the world, with extremely reasonable postage costs.

BTW, those test benches seem to be run on either glow fuel or model diesel fuel, not biodiesel exactly, althtough Ken Enya may advise you best.

A good source for real diesels would be small industrial engines, like the single cylinder series from Yanmar and its clones. I have one of the clones (Yanmar L-48 equivalent) with only 30 minutes of run time on it yet > http://www.youtube.com/watch?v=hhmJvpNlfIM

Get in touch with 3w and ask about their in house heavy fuel engines. Last I heard (public open access) they were in the process of selling the engine type to whatever company was willing to buy their patent. I don't believe they are a true compression combustion engine but they do pretty good. They use a type of ignition for combustion assist.

If you are not familiar with 3W, as T.O.M noted www.aircraftinternational.com

Even more specifically http://www.aircraftinternational.com/3WHeavyFuel.aspx

Biodiesel's autoignition temperature is much higher than a model engine can achieve in the cylinder. By adding ether to the fuel mix to make a fuel similar to model diesel fuel will result in an engine that runs, but the quantity of biodiesel that actually burns is questionable because the vapour pressure is low and boiling point is high.

Look for small stationary four stroke diesel engines like the Yanmar or equivalent as mentioned above. The 3W heavy fuel engines are spark ignition.

since they use ignition and the Walbro carbs, I suppose they make a premix to get a good aerosol into the cylinders that can be ignited.

The web page mentioned something about the carb acting like a fuel injector. Many companies have built heavy fuel SI engines. Some use air assisted injectors to atomize the fuel others have used heated manifolds. I've never read anything about biodiesel and spark ignition. Biodiesel is quite a bit different than the JP-8 most "heavy fuel" engines burn.

I would hardly call jet fuel "heavy fuel"
In ships engines the normal viscosity heavy fuel is black crudlike thick syrup, and needs heating to be pumped. Car diesels also use heavier fuel than jet engines. Car diesel fuel still rates as light fuel.
Bio diesel mostly is car diesel fuel where the heavier bio oils are mixed in with about 10% - 40%

Yes, JP8 is not very heavy, but this is the lingo in the industry as compared to gasoline.

Biodiesel, as referred to in the US, is usually B100, 100% soy methyl ester. Various blends with regular auto diesel are available B2, B11, etc.. Other base oils are also used, canola or corn most commonly. The Wikipedia page has good info.

http://en.wikipedia.org/wiki/Biodiesel

That black crudlike stuff is "Residual Fuel." The price makes it attractive to large, slow speed diesel operators, but there is a caveat. You cannot let the engine cool off with Residual in the injectors (assuming you want the engine to start again.)

The engine is fired up on distillate (diesel fuel) and run until hot, and the residual is heated to high temperature with pressurized steam heat exchangers. When the residual will flow, it is switched into the supply and the more expensive distillate is switched off. Before shutdown, the distillate is switched into the supply, and the residual is shut off. After a suitable amount of "flush" time, the engine can be shut down without sticking the injectors.

Residual, if I remember correctily, is what's left after everything profitable is distilled out of the crude oil. One colleague called it the "Tailings". Heavy? You bet!

Now why did I bring that up.....??? Oh, right. Just FYI.
Dave Olson

Not for me! I started out my frofessional life as a ship's engineer. Long, long ago

I already work with "heavy fuel" 2s engines so I know that it's not theoretical. The stuff works.

The heavy fuel engines you're working with burn what fuel? Or are you saying biodiesel works in heavy fuel engines?

JP. It should not be all that difficult to jet and atomize for the bio diesel but you might have to consider a couple of factors first. I can't enlighten on the subject any further. Contractual obligations prevent. 3w has what they would need informationally.

JP8 SI engines have been around for several years now. No reason to doubt that. Biodiesel and spark ignition though I've not heard of.

I found this today, it should work for your purposes:

test station: http://www.enya-engine.com/store/ind...roducts_id=457

engine: http://www.enya-engine.com/store/ind...roducts_id=333

email sent.

That still runs ether in the fuel.

Greg

Take whatever product the students create in the lab and add a set amount of ether and oil to it.

I just ran across a usable test bench, that is all and thought I would share.

The Enya website actually states that it is for "domestic" market only. Certainly they would be able to make an exception for an educational institution.

Now that I think of it, they also make one for the glow .11cx engine as well, which is a glow engine. Perhaps that would be better as it wouldn't require the ether. Maybe convert it to EI.

The problem is that the engine will burn a limited amount of biodiesel even with ether. It's not going to be much of a test. A reasonably large size injected diesel engine is needed to test biodiesel. I've not seen any attempts or mentions of running biodiesel with spark ignition.

Good point. A small diesel engine (5 hp?) would be best.

Now that I looked up the thread a bit, I see Patxipt has posted this test bench already. Sorry!