Wood and charcoal hybrid

i just finished building a hybrid wood and charcoal gasifier. it is most definitely a work in progress, although at the moment it does seem to work. here is a video of it working.

what i have is a small updraft wood gasifier unit, which feeds a simple fire charcoal unit. the small hydraulic ram you see is full of wood shavings to act as a filter before entering the engine.

like i said this is most definitely a work in progress, i’m having to use what little resources i have due to a very tight budget. the wood unit is definitely not air tight unfortunately. this setup is definitely more for a proof of concept anyway.

the inspiration for this setup came from something wayne said… “gasification is simply passing wood smoke over glowing hot charcoal”

the idea here is that i could use bigger pieces of wood in the first reactor, which should hopefully pass through the charcoal unit which will hopefully clean up that dirty smoke into engine grade gas. big pieces typically make very dirty, crappy gas, but if it can be be cleaned and have the tars cracked by passing through the charcoal reactor then it would mean far less wood processing would be required. the chunks im running in the video are anywhere up to 6" by 3" pieces of 2x6, so not huge but definitely bigger than ideal gasifier feed stock.

i chose the updraft unit simply because the reactor vessel is not air tight, and even with the engine running i could not get it to pull air downwards through the 1" hole. however, i do remember reading somewhere that updraft units do typically produce higher volumes of gas, but it is very dirty, so possibly the updraft unit may be a good choice to stick with.

the next question is whether or not this combination unit will go through less charcoal than a unit running strictly charcoal, and if it does use less, how much less? substantially? or barely at all? becasue if it doesnt use much less charcoal than a charcoal only unit, then it doesnt seem there would be much point to this.

anyhow, please share your thoughts and possible problems or improvements i could make, thanks!


So it’s basically like a Brandt gasifier but in two separate parts?

The Brandt used a wood hopper and charcoal hopper separated but inside a single unit.


Welcome justin, it looks like you have been doing some reading on how to build.


Hello Justin and thanks for the video.

The above may not be original from me but somebody on the DOW ( Steve Unruh I think ) .


never heard of the brandt, but sounds very interesting! i will have to look into it.

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sorry for the misquote wayne, i saw you mention it once so i assumed it was yours. thank you steve unruh!

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i have done a ton of reading on different builds. i have been lurking here for years, with the odd post on different theories, but this is my first actual build.


Yes it was me saying this years ago. AdminChris pinned it here:

Important JustinH. that the pyrolysis/smoke off gases are passed THOUGH the chunks of glowing hot woodcharcoal.
Mine was my understanding overly simplified at that time to be make easy understood.
Jim Mason explanation is much more detailed, classical.

Time has advanced along. Just today DOW friend Tone shows that he can working engine power using chipped shreded woodie debris. Read that.

In the last 18 months DOW member Joni has indicated he is using on his European Opel car a one-zone system based on the theoretical work of a Soviet era theorist. He seemed to be getting the engine power. And lowered fuel consumption on fairly wet shred woodie fuel stocks too.
The war has interfered with his Life now.
His system will be the direction I will be going now to prove, and use. Very light weight for small cars and generators.
Ha! Just have to complete my wifes slow moving us 60 miles endurance race before I can get to welding the SS. ( Shhh. So instead I hold back monthly money accumulating to be able to buy the expensive used all stainlees steel barrels and SS buckets to make the building go faster and easier.)

Good to see you DOing now, man.
Only Burning is Learning! (yes, me again - I am a woodgas motivator)
Steve unruh


I did a little lurking my self before I began to speak up in the different threads asking questions on wood/charcoal gasification that were being posted. That was a fews years back now.
Now some might think I talk to much now. Lol. Okay a (heart or like) doesn’t mean you agree with the last statement I made.
I wonder how many are out there that have been lurking around for some time now… Hey you people out there, speak up, we would like to get to know you all.


I believe he typically uses rebak chunked fuel, but yes his probably has the most flexible fuel size usability. His system is also easy to fabricate I think. Can use obtainium or roll up your own from sheet stock.


Joni really knows how to fabicate and work stainless steel to make a great gasifier to make that wood and charcoal work for him 100% of the time.
I don’t think he ran his car on gasoline or hybred driving. He raised the compression in the engine.


Justin, keep us posted of your continuing progress on this build of yours, very interesting.


They will need to create a new award badge. “” the most liked comment of all time!!" haha.

Just kidding buddy, you play a big role in keeping this alive. Keep the comments comming :slight_smile:


i’m curious if anyone has found a way to test a system for tar without having to actually run an engine and find out the hard way? i was thinking of building a cyclone that introduced fresh air as well as the producer gas. i wouldn’t even necessarily flare the system off, just run it off a blower for 30 minutes or so and then check the cyclone for tar?

i think the reason tar always ends up in the engine is that our gas never comes into contact with fresh air until then, and that mixing of air and gas is going to have a much greater heat exchanger than any external heat exchanger ever will, and it lets all that tar and oils finally reach their condensing temperatures. so i’m thinking maybe a fresh air/gas cyclone ran off a blower for 20-30 mins should be able to tell if the gasifier is a tar machine or not.

if anyone has a simpler way to find tar without crossing your fingers and shoving potentially tarry gas into an engine let me know!

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You could probably mix the air together, and run it through a pre weighed amount of wool or cotton material and burn off after that. Weigh the fluffy stuff to see if it caught tar.

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would there be a danger of burning back into the cotton/wool chamber since the air is already mixed with the gas in there?


You could make a backflash arrestor using copper mesh. Jam that in the flare pipe. Flare would just be to prevent smoking your neighborhood if it comes out all foggy.

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Most of the tar problems come from using wood that had not been dryed enough, and that takes a little experiance too learn how dry the wood must be, allso if your car sits and cools down after driving on wood, if there was any tar run through the motor, your will feel the throtle plate stuck or sticking, in that case one should turn the motor over a full revolution by hand, knowing your gasifier design wood moisture capable, is the only way i can go by. And keeping the cooling rack cleaned when needed.


Only armchair knowledge.

First of all, dont mix gas and air. It is explosive! Do that just before the engine intake.

Cool the gas as fast as possible. If it is hot , it wants to decompose. At low temps it will stay ok.

Tar is unburned fuel. Take another look at your gasifier.

I like your setup btw. Out of the box building. Thanks


Hi Justin congrats on your duel fuel system , i too have been running the same system for a couple of months now , when weather permits , i use a updraft 55gall drum for charcoal , and a smaller drum that i fill with wood briquets and a mixture of plastics and draw that through the air intake of the larger charcoal drum gasifier , run time hours are not more than about 25 hours so far , but no problems with tar in the pipe work or the engine , i run a 7kva inverter generator for roughly 4 hours at a time as often as needed , so far its a little hard to work out the fuel run time using the 2 drum duel system busy trying to construct a sheltered area i can move my stuff too so i don’t get soaking wet when playing .