Chevrolet s10 4.3

#227

All the time. Thats the problem with idleing for too long, charcoal only gets used up in the oxy dation zone and maybee in the restriction, but the reduction only gets “cool” gases wich means its dead and it acts like a filter, collecting dust, makeing a tight charbed.

From that same reason. Idealy, you want your gasifier sized so that the part above the restriction is only oxidative, restriction is the hotest part of all gasifier, then a reduction zone big enaugh to react all the heat, CO2 and H2O to form woodgas but NO LARGER so that the reduction zone doesent produce drag and breaths nicely.

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#228

How can restriction be the hottest place?
Hasn’t the reduction of gas already begun above it?

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#229

Not idealy. The oxidation zone on a true lmbert is, you culd say, tiny. It is in a way only responcible to burn lots of wood fast in a wery turbolent enviroment. Then concentrate the heat and turbolence in the restriction, thus the heat is highest there. Tars burn and crack. Then enter the reduction zone super hot and tar free.

It was later noticed, with air preheat, longer dwell time etc the oxidation zone can be made much larger. Look at a WK, its nothing but a supersized oxidation zone :wink:

4 Likes
#230

For your engine the sugested oxidation zone for a true Imbert (by Maxs Gasmans formulas is around just 1.5l in volume! You can imagine wood has barely enaugh time to even fully convert to charcoal in such a small but extremely turbolent area.

Anyway, l certainly dont suggest that kind of a lmbert. You have 2 options with woodgas. Go big, slow and cold or small, fast and extremely hot.
My “shoebox” gasifier for my mercedes was the later. Absolutely tiny reaction zone, but so hot inside the ash turned to actual glass. Reactions happened instantly. That tiny thing made a ton of great gas but did not withstand the heat due to some design flaws (thermal stress).

I may seem like l am talking BS here. The other day l told you your gasifier is too small, now l tell you the gasifier needs to be small. Its complicated :wink: each design works but only if you follow some rules and principles. Mix to much and you end with crap.
Since you have space its probably beter to go the other way and go big on the gasifier, like a WK. It is simpler to make it last a long time compared to if you go with a small/hot gasifier. Everything suffers there.

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#231

Thank you Kristijan for taking the time to answer my questions.
It’s sad that I can’t buy the book from Wayne, so I could see his construction.

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#232

Wow, KristijanL.
Finally someone who truly understand the gasifier relationships between T, T, And T biased systems.
And explain this in simple direct terms.
Good I can go to sleep now. I tired easily anymore.
Regards
Steve Unruh

5 Likes
#233

Have been driving the car all week when I look at the sheep, have moved them to where I live in the winter, so that they eat the grass there a little.
Drive about 30km every morning, the car works well but not so good, found a leak yesterday between the unit and the cyclone, so I thought today the car is probably going well, but went worse than usual, feels like it gets too little gas or that there are several leaks.
The coolers get hot on both sides, which they don’t usually get.
But still have problems with bridges, wondering if the wood is still too large, has only birch.

(https://youtu.be/TVwBW-ZVJWI)

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#234

Ha, I suspect your 4.2L engine is pulling pretty hard on that little 9" Imbert :smile:
I think I would experiment with making even smaller fuel. And when you get fed up doing that you may find it less work to build a bigger gasifier :smile:
That was not Hörken you passed, was it?

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#235

Went from Hörken towards Yxsjöberg, crossed the road to Sjöändan.
I found a leak today, but no difference.
Has cleaned the cyclone, and hopper, found 10 liters in the cyclone. Wondering if I can have water in the pipes from the filter to the engine, which fails.

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#236

No water in the tubes from the filter.
Can the hay in the barrel become dense so fast?
Surely that’s the only thing left?

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#237

Did you ever try mixing charcoal with your wood fuel?

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#238

Ash/char, I hope?
Remind me - do you still run without a grate? When pulling too hard for too long, eruptions sometimes occur in the reduction and more char than I like slips into the cyclone. I try to always treat my grateless gasifier gently.

Water in a low spot or high water level in the hayfilter creating a bubbler, doesn’t usually affect high end performance much. But you will have a hard time keeping a low idle. Especially letting the pedal up too fast will throw off the a/f mix and stall the engine.

I doubt it. I wash it down with a couple buckets of water only a few times a year and I lose only 1/6 of the vacuum across the filter.
Any wet part of the piping can of course plug with soot but most likely with a plugged system, charbed or grate are responsible.
BUT - since you don’t use vacuum guages and you’re not sure you’re plugged, it can be the other way around. You reported hot rails and a lot of char in the cyclone. Maybe your char is too coarse and you’re pulling oxygene too low.

Ha, you probably realise by now I’m just guessing :smile:

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#239

Don, I have not tried to mix in coal in the wood, the car went better before, responded to the gas and reacted to the secondary air better.
Now it seems that I have either too much gas or too little gas, get no good middle position on the air.
JO, I have a roaster now, thought it answered a little better since I cleaned hopper, but it only lasted a little while.
How big should the coal be under restriction, can I have too little coal?
Coal in the cyklonen.

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#240

This defenetly looks like you are overdrawing the gasifier. Like JO sayd, grateless gasiiers are prone to eruptians.

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#241

That char/ash looks exactly like mine. But when I used a grate on the VW gasifier, I collected only dust in the cyclone as long as I kept cleaning out below the grate. Only when the space below the grate was full, char started to exit into the cyclone.

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#242

Kristijan, I have a grate, but it does not cover the entire space, maybe I should put in a ring that holds the carbon better.
Mayby i should put in bigger coal.
Excuse my bad English.

1 Like
#243

Now I have put a ring on the grate so that the carbon does not roll down to the bottom.
How should I drive the car so that it does not carry carbon to the cyclone when I have an automatic box?

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#244

In the first picture, is the grate resting on the charcoal that carried off the grate, or through the grate? What is the diameter of your grate? With your size engine at 2000 rpm, the velocity I think is somewhere around 35 litres per second. That will carry a lot of light charcoal. How close to your reduction is the grate? I hope it does not plug up with that ring.

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#245

Jan, I admire your persistence :smile:

Slowly :smile: Just try keep as low rpm as possible. Open up the air valve and add gasoline if you’re in a hurry. There’s no way this little gasifier can satisfy a 4.2L engine at WOT.
With reasonable power demand and enough empty space below the grate char will stay put. As soon as char shows up in the cyclone you know that space is probably full and time to rake out.
Hard to tell from the pics but your grate may have somewhat wide slots. Drive very carefully for a couple hoppers and let things settle. Ash and soot will fill any unnecessary voids. Try not to disturbe the charbed, apart from careful cleanouts.
That’s all I can think of for now.

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#246

The roster is on the macadame (ground) just to show how it looks.
The second picture is from the inside, from below.
The ring is about 16-18 “.
The gap between ring and reduction will probably be 7-8” but to the 9" pipe ca 3-4".

3 Likes