Ok, i don’t think that should restrict too much, but the vacuum readings talks for themselfs.
Can you “double” the piping easy? Or change it to somewhat bigger?
1 Like
Interesting information. I will have to do some experiments myself.
I think just as important for power is that less restriction means less throttle and less throttle means less retarding of the timing.
3 Likes
Jan are you still only using the one corrugated hose to deliver gas to the engine? Maybe it is time to check if it has soot constricting the flow.
3 Likes
Corrugated hoses also have a high flow-restriction, especially if they are to small for the flow.
3 Likes
Oh okay you’re using stiff sump hose. That shouldn’t be a problem then.
1 Like
That is good 
Not much restriction in those hoses.
2 Likes
Do you have a heat exchanger later on? In that case yes.
3 Likes
No, I don’t have pre-heating, I thought about removing the insulation and making a can around the unit and taking the air from it…
4 Likes
That would be making a heat exchanger for in coming air. And it would help cool the gases after leaving the grate. So after my gases leave the grate and go into the drop box I have no insulation. I do have some insulation so I will not get burned off the lower barrel, at the grate above and below it is over 1000 °f . It will burn high temp. Paint off the metal so I need some insulation for protection reasons. But a metal shield around it would protect with air movement would work too. Remove the insulation and leave the metal shield to see if it will work to heat the incoming air.
Bob
2 Likes
That sounds like a good idea to me.
1 Like
When you preheat the air, is it to be able to put in bigger things without it becoming tar, or why preheating?
A 12" fire tube can handle larger pieces of wood but a 8" fire tube can not handle wood the size of your fist as easily. Firetube diameter can be the factor here.
Bob
3 Likes
Yeah I would say hearth diameter is what dictates fuel size compatibility.
Even if I built a baby WK with all the preheat but with a 6" diameter hearth, I’d probably only get my best performance with acorn or pingpong ball sized pieces at the biggest. If only wood pellets didn’t make such a soggy mess in the hopper, that would be a fun motorcycle build.
3 Likes
Oh, yes you can use bigger nozzles and a larger restriction. Improving the efficiency can let you improve the flow.
Your gasifier already has a full air jacket, right? You could add another air jacket over the bottom section like Jan-Ola did with his Volvo gasifier. Or replacing the cyclone with a drop box and make a heat exchanger around it.
Or around the muffler. Only place I wouldn’t put an air jacket would be the catalytic converter, it needs to be at an optimum temperature to work properly.
1 Like
I like the top of the firetube down to nozzles about 3" . Then from the nozzles to the restriction opening about 6" .
Then from the restriction opening down to the top of the grate about 9". The total is around 18". I think 3,6,9 are good numbers to work with in a gasifier. The Tesla ratio.
12 " firerube diameter is good for wood size and Charcoal flow down to the grate. No higher temperature then 1750°f at the grate. Or 850°f at the crossover pipe. More air flow through the nozzles and the hotter the better air is good too. Any moistures going into the super hot lobe zone has a good chance of becoming Hydrogen. This equals more powerful gases into the engine.
Bob
2 Likes
Cody, I’m pretty happy with the cyclone, don’t know if I want to replace it, but I know how much resistance it gives.
Bob, I almost have your measurements, I think I have a little less between restriction and grate.
However, I see that I have very little restriction against you, I’m not quite 5", and you are 7.5".
If I recalculate your restriction, I would use 6.8" restriction.