It might not apply on a woodgasifier’s oxidation zone, but it’s kind of what I was aiming at when using two separate nozzle manifolds. One closed off at low demand.
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Hi Greg, I am sure you can change your reduction tube by placing a round plate with a smaller hole and weld it to a smaller tube that fits inside the larger tube. It is the increased speed of the gases going through the smaller plate hole that makes the change.
Bob
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Hi Jo,
That a quote from a quote 
Indeed, keeping the nozzle airspeed “steady” also improves the overall performance, with a few “but’s” and a lot of “if”
at the end it all boil’s down to “DOING” it and “LEARNING” it by doing…
@Greg1, imagine each zone separate, each with its function to do, find the balance for each zone and how to make the transition from one zone to another…
Change in fuel is shift transition, for the better or for worst…
Change in airspeed idem dito…
Change in moister …
Its all in the balance between exothermic reactions and endothermic reactions
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Greg,
Don’t take me too seriously please. My ideas on this are still half baked (not well formed). Kristijan has now given me new information to think about.
I know that the steel making furnaces at Sheffield in England were charcoal fired and air blown. A gasifier is very similar. So I think that anything metal in the reduction zone may not survive for very long. And the reduction zone is changing size and shape and position all the time. It becomes hotter and smaller with smaller fuel, larger and cooler with larger fuel. Obviously it gets larger and smaller as gas is produced faster or slower. So it seems to me that maybe it is not worth wile to even try to measure reduction zone temperature. Is there something we CAN measure? So I suggested Mass Air Flow. This is just a suggestion.
Thank you all for this discussion and for putting up with my questions and ideas. My thinking had come to a standstill. I needed new information and outside ideas. So now I’m moving again. Thanks.
Rindert
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Yes, Bob, I had considered doing that for the first run, but I worried that the hole (called the ‘choke’ by Ben) would not be big enough, and the charcoal would pile up around it without falling through to the grate. I do plan to have the generator bolted to the gasifier so the vibrations will help that. And the grate movement will help, so we will see.
The existing reduction tube is about 4.5" diameter and existing choke hole is 2.5". I’m trying to decide what diameter to make the nozzles - could be anywhere from 1/8" to 3/8" with easy changing. I hope to observe the effect of different nozzles by observing performance while holding other variables constant.
I also have a large reduction tube with choke plate, not installed (shown in picture) for use in a future experiment with a large engine.
It takes probably an hour to change the reduction tube - You have to remove the ‘victory hearth’ and the insulation it contains, immediately around the hearth. So it will certainly be possible to do what you suggest. Thanks for your attention.
So you are saying the speed of the gases going through the plate choke hole is more important than the speed going through the nozzles?
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Yesterday I lit the charcoal in my gasifier with a sparkler and managed to get a flare.
In the process, however, I melted my thermocouple that was right in the hearth. I didn’t realize it would get so hot so quickly.
I plan to try it with a generator tomorrow.
Thanks for all your ideas and help.
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Yep it sure does get hot down there when on charcoal , looking forward to see the video with the generator running .
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I haven’t been following this word for word, but I must have missed something. Why aren’t you burning wood in a wood gasifier? I have Ben’s book, you should be able to configure it to run almost any engine.
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With wood, the smallest engine it can take is 500 cc, according to the book. I have 3 generators and they are all about 200 cc, so Ben suggested I try charcoal, because you don’t need as much engine suction to get good gas. I also like charcoal because there is less chance that I will tar up my engine.
I extrapolated nozzle diameter, choke diameter, reduction tube diameter etc for my smaller size engine, and used charcoal instead of wood. I hope to get a generator running soon. And in future, it is fairly easy to upgrade to a larger engine with wood.
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there is also the solution of the gazo brandt not to dirty the engines with a mixed, charcoal and wood.
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This one minute video shows my failed attempt to get a 196cc propane generator started with woodgas. The sequence in this video happened several times over a 3 hour period. Would have loved an electric start.
For my next attempt, I propose to pipe the woodgas into the port on the carb where the propane normally goes. (Instead of where it is going now, which is where the air goes)
Also, my charcoal is 1/8 to 1" and I’ve heard it should be smaller, so I propose to try 1/8 to 1/2".
Any other suggestions?
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Thats why I will never wood gas a pull start engine. It sounded like you almost had it though just before the video cut out. When it tries to fire, you are either at mixture, just beyond or just under. When it tries to fire do nothing and try a few more times, If it does not fire, turn back a fudge and try a few times. If still no fire then go just beyond and try again a few times. Generally once it does fire I have to adjust back slightly to the rich side.
If I dont have electric start especially on a new machine that I have no idea where it wants to run at. I will run on gasoline and feed in the gas. How you do this is open your flare cup wide open and the mixer wide open while it is running on both gasoline and wood gas. It will run very rough until it runs the gas out of the float bowl. As it runs out it will smooth out as soon as it does I close off the flare cup as it continues to smoother out I then start closing off the mixer valve to where it runs smooth as it fully transitions off the gasoline. This take a bit of practice but you will learn quick where the sweat spot is first couple of times. Then if your first attempts fail the next you will know where that spot is and can then adjust right to it as it runs out of gas.
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Just as Mat explained for starting on petrol and charcoal gas at the same time , now if you want to start on 100% charcoal gas then take off the pull start cover and get a socket and extension onto the nut and then spin the engine up with a hand held drill while adjusting the air mixture , worked very well for me on my engines with no electric start .
Dave
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I agree that it sounded like you were getting close. It was sort of hard to tell from the video how far the gas has to go to get from the flare blower to the engine - bear in mind that you will need to prime that whole length of pipe with good gas before it will start. Your flare looks good, so I think that if you can pipe that gas into the engine you will be in business. It wouldnt hurt to double check all your hoses and make certain there are no air leaks - duct tape is not elegant but it does work!
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Greg,
As suggested above, it may be that it just takes too many pulls to move the gas to the carburetor. Also, I think that if good gas doesn’t start flowing quickly, it soon becomes diluted making it more difficult to get the proper gas/fuel mixture. Furthermore, gas is only being produced when there is suction on the system. That hesitation just complicates things even more.
I sometimes had trouble starting my rope-start push mower on charcoal until I moved my suction blower so it would pull the gas right over top of where the air originally entered the carburetor. After starting the engine, I remove the blower hose and screw on a filter in place of it. The point is to get the gas to the carburetor, before pulling the rope, either by pushing or pulling the gas there. Early on I was impressed by a YouTube video of a guy nicknamed “One-Pull Al.” After that modification I became “One-Pull Steve.”
In my case, I have a T-fitting over the carburetor. The stem of the T fits where the air filter originally was. The gas line fits on one side of the T, the air mixture valve and then the suction blower are on the other side. I open the air valve all the way and run the blower until I can get a flare. Then I remove the blower hose, adjust the mixture valve to a predetermined sweet spot, pull the rope, and away we go. You still have to determine the sweet spot, of course, but I think it is easier this way because good gas is already at the carburetor when I pull the rope. It works so well that I set up my Toyota to start the same way. I’m not sure of your configuration, but something working on similar principles might work for you as well.
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Howdy
one of the reasons the Europeans put a check /flapper valve on the gasifiers air intake… Once you have it up to temp turn off any fans, the valve will close and the gasifier will begin to build pressure… Give it a minute or so and it will push the gas to the engine you will smell or see the gas when it gets there. close the air valve and start pulling or cranking… slowly open the air mixture til ya get some happy.
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This sounds so good Steve. I can’t wait to try it and I’ll post the results.
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Terry, This gasifier does have a working check valve on the air intake. I did measure an increase in gas pressure right after turning off the blower, and this is shown in the video. But the pressure decreased after about 4 pulls. It seems it was still not enough gas to get the job done.
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Carl, The hose from gasifier to engine is probably way too long. It’s about 10 feet. I didn’t realize that was so important. I’ll take care of that before my next attempts. I appreciate your judgement of the flare. Although I have little experience, it did seem powerful to me and the gasifier seemed to perform well.
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A great idea! My own electric start. Can’t wait to try it. Thanks Dave
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