Retrofitting Two-Stroke Engines To Run On Biogas?

by Thomas H. Culhane, Solar CITIES

I've been reading your "future of two-strokes" with great interest, "scavenging" (as it were!) information to see if your lessons can be applied to third world development. As you are probably well aware, longevity, cost and replace-ability issues make two-stroke engines the favored solution for developing countries, yet their emission problems and inefficiencies make them a nightmare.

A company called "Envirofit" has created retrofit kits that use a new cylinder head with direct injection to reduce emissions in the Philippines by 90% and give 35% better fuel economy. What we are trying to do in Egypt, however, is to find a way to run two-stroke gensets and vehicles off of biogas (60% methane, 40% CO2) that we make ourselves. We have the converter kits for the carburetors from US Carburation in West Virginia so we are not using DI, and we can get the engines to run on our biogas. But of course we can't lubricate them so engine failure will happen in short order. Do you have any ideas how we can lubricate a two stroke engine if we aren't introducing the oil as part of the fuel? You mention direct injection lubrication - how might we do that? Any ideas would be greatly appreciated!!


T.H. Culhane

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Jan 31, 2012
Thank You Tim, Looking Forward To Your Results!
by: Thomas H. Culhane

Thanks Tim.

Love your thoughts and the direction you are heading and I couldn't agree more with your insights. Raising the mpg equivalency and working with biogas and hydrogen boosting, where one only needs limited quantities, is a perfect solution.

I'll be eagerly watching this thread to hear more news of what you develop! Would also enjoy your participation in our international Solar CITIES Biogas Innoventors and Practitioners group on Facebook! Cheers.

Jan 30, 2012
Biogas In Two Stroke

Which engine are you using? In a 2 stroke engine there is a separate oil giving set up.

Sep 24, 2009
Lubricating Two Stroke Engines For Biogas
by: Anonymous

Thanks Tim! I appreciate both your technical advice and your insights.

Right now I am working on stationary applications of biogas for engines and generators until I get the compression and purification issue worked out. I read a technical paper from India where they used a sealed reciprocating compressor for hydrocarbons - I think it was actually just a refrigerator compressor! - to compress biogas and they used a water bubbler to scrub most of the CO2 out (CO2 is more water soluble than CH4).

But for now I just need a way to get the oil into my two-stroke 650 watt generator which I've already modified to run on the biogas (it works nicely, but I keep having to add oil through the spark plug port after 3 minutes to keep it from burning up, and I'm told this won't lube the bearings).

Your suggestion was awesome, so I'm going to check it out! Hope to hear more and share more as things progress. Good luck on the 300 mpg - it's great! And thanks for the tip on hy-boosting. Roy Mcallistairs videos from have been helpful there too!

Sep 21, 2009
Developing Countries
by: Tim Hickox

The answer I gave was very general. I want to say that I am particularly interested in these applications for developing countries.

As for the lubrication problem, Yamaha's Autolube pump will meter oil in relation to rpm and load (throttle opening). The oil is drip-fed into the inlet tract and is carried through the engine by the air - so the fuel is not involved. Adapting one of these pumps to any engine is simple - IF you can find a simple way to drive it.

Keep reading! I'm going to describe a DFI system that uses a carburetor. It's very simple and cleans up the two-stroke. We get the advantages of DFI without the costs and complexity. This is perfect for the sorts of engines you use.

Sep 08, 2009
by: Tim Hickox

Hi Thomas.

For now, only gasoline makes sense for dirt bikes. BUT, this question really pertains to this 300-mpg vehicle I'm working on. We have to stop taking oil out of the ground (the CO2 that nature has been storing away for millions of years) and dumping it into the atmosphere. The scientists now estimate that if mankind disappeared tomorrow, it would take 60,000 years for the oceans to return to the pre-industrial age condition!

Biofuel is a good idea, because it is carbon-neutral. But we can't make enough of the stuff to have any real impact - so long as people are driving things that get 30-mpg. This is why my efforts are aimed at moving people from A to B, with an order of magnitude improvement in efficiency.

Once we have that problem under control, a bunch of new options open up - which are not practical for lead-sleds. THEN, we can use biofuel. But more, if we add just 5% hydrogen, we can extend the lean-limit of the hydrocarbon fuel and get an improvement in efficiency of about 25%. But hydrogen, like biofuel, is not practical if we need large quantities. But 5% of the fuel for a 300-mpg vehicle is not a problem.

You see, we have technological solutions, but we also have companies that have invested billions of dollars in stuff intended to make then richer, at the expense of everything else - the whole planet!


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