George, the engine is not harmed by water vapor, as combustion also results in the formation of water vapor, except that the proportion of sulfur in the fuel forms harmful substances, otherwise Kristjan would have known more about it. Good sketch of the gasifier …
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I’m liking those water cooled nozzles, especially the ones in the French link. The one in the wishart drawing seems like it is too low and would get obstructed with ash before long.
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hello friends and experts…a thing what for me is not clear…here on the forum are some discussions about automatic air gas mixers, their problems and their solutions …
i have tried only on maximal 250ccm engine the simple mixer , shown in an upper part on a drawing, this is only to regulate when the filter becomes more closen, otherwise works well at idling and different power.
the same argument i have read somewhere on a post of wayne keith, he only must regulate when filter becomes more closen, and he uses a big engine-cars.
what is the difference??
i have the mixer immediately after the filter, and than is a more or less longer hose to the engine. where wayne keith has its mixer positioned, i dont know…
maybee it is a question of flow resistance?
cars have the air filter near to the engine, so the right mixture in idle is not the right on more speed, because of less resistance way, comes more air in the mixture when comes more suction from the engine?
who can clear up the fog?
thanks giorgio
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Giorgio, I think most of us don’t bother with auto-mix since woodgas burns ok in such a wide range, it doesn’t justify the complexity. @KristijanL and @Bobmac are probably the most experienced in auto-mixing and could chime in on its pros and cons.
Personally I find myself not adjusting the mix much at all. A cold gasifier, a long idle or a tight charbed may require a slightly richer setting. Other than that very little adjustment is needed. In my experience filter restriction is minor.
I agree though, the mixing-valve should be positioned as close to the engine as possible for fast responce. Especially if you’re cranking up straight on woodgas.
Don’t know if this was helpful at all. You seem to be well on your way as is 
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Yes , what JO said very well 
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True. A vacuum automixer, wich Bob has (built by Chris), and l had on my Chevy has its limitations. It works good when the sistem is warmed up and runing at its best. I am willing to bet it also makes driveing more efficiant since the gas mix is ideal in every kind of gas demand/engine power, while a manual setting is a kind of average.
But for every other scenario its preety much useless. When warming up its going to run lean. Ift the gas becomes rich, like in a case of going full power down to low power, the engine can even suffocate. Not to mention air leaks, they are a no ho with a vacuum automixer while on manual seting it can be adjusted for them.
This sayd, l dubt l will ever be making a vacuum automixer again, maybee for a stationary sistem. But there is always that “it depends” thing… while my Mercedes hadnt even had a from the cab adjustible gas mixer, it was just set to what ran best and never touched again untill the filter had to be cleaned, my current ride, Škoda, is extremely picky on air gas ratio. Not sure why. I will be naking a electronic mixer for it if l get tge time any time soon…
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Hi Giorgio, I will NOT be using a auto mixer in my next build. It is not needed, and I have had to spend way to much time working on it, which means less time DOW. Just go with the manual controls. It give you the operator more controlling adjustments when operating your gasifer.
Bob
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Robert, I partly agree with you, probably for driving a car this is true when the driver is present behind the dashboard and making corrections, but if the engine acts as a generator and the load is constantly monitored, things are different, similar is a working machine.
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The one nice thing about a auto mixer is anyone can get behind the wheel and drive my truck. I proved it at Argos a few years ago. One boy was a student driver. His dad went with us for a drive. Lemons would have not helped with the SWEM that young boy had on this face.
Bob
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Not flow resistance, but inertia of gas flowing in long pipes. The automixer is only useful when speeding up and slowing down.
Rindert
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Speeding up and slowing down yes, but at a idle I can push or pull on the air mixing valve control rod and get the ratio off the 1 to 1 , let the valve recenter itself and you have now a 1 to 1 air/gas ratio again. As long as the gases are moving through the auto mixer it will open the air valve according. In fact when you take off from a stop there is a little lag time for the air valve to open up. This gives you rich gases for a few seconds and this helps with the engine acceleration.
Bob
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Bob, you have two air adjustment valves right?
Your automatic mixer controls the fine tuning for air? Or am I mistaken and you only have one air valve with manual override.
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I have two air valves, one is the manual 2" when running on gasoline or opening it up very little to hybrid or just adding extra air if needed. The other is my auto mixer valve it opens up when the auto mixer is in service. My two 2" gas from my gasifer are not air tight valves and they come together into a 2" line. Off of one of the 2" gas delivery lines I have a 1" line to modified motorcycle carburetor valve that is air thight when closed. It by pass my auto mixer so I can add extra wood gases to the engine to force it to run richer wood gas ratios. The auto mixer operates the same. So if I open my 2" manual air valve a little I can now manually mix more air into my engine then the auto mixer could do by itself. It was limited to only 1 7/8 opening on would gas into the engine. So now I have a 2 7/8" gas delivery to my 5.2 L engine. I can now over pull my gasifer at highway speeds. Before with the auto mixer only, I could not. This gasifer can run a 5.8 L engine with no problems. It has the same size nozzles of the old 8 nozzle firetube but now has 12 nozzles.
Bob
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another question comes up : how much dust is allowed??
the answer i think of course, -less as possible!
i use stainles mesh for filtering- the charcoal is normally very dry.
the mesh has 4356 mesh at one quarter inch (is 676 mesh at one quarter cm)…
is this mesh fine enough?
besides a foto of the throttle after 6 hours run…
who has experience?
ciao giorgio
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Giorgio, I use a canvas sack filter for my Mazda. Since I adopted that I do not have soot on my carburetor. Maybe the mesh isn’t tight enough to grab the smallest of ash and soot?
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thanks cody…i will make some try with sacks-bath towel, and the metal mesh inside for security, in case the sack not withstands the heat, my filter is also cooler…
the suction of a bigger engine like as your mazda is shure more strong as my little 250 honda, so maybee the filter plugs quicker???
after trying more wisdom
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Giorgio, unfortunaly the answer is NO dust. Unlike soot from a wood gasifier, wich does not hurt the engine, the dust from a charcoal gasifier contains mainly ash and particles of slag (glass) wich is real bad for the engine!
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I used the similar format like you described. Towel bag with a screen on the inside to hold it’s shape and be a backup catch screen.
When the dust collects on the bag filter it helps it filter even more. Using the filter so dirty gas is outside and cleaned gas is inside the bag allows the ash and soot to settle off.
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