Max, my point was only the volume of gas, which helps me get up to speed before the hesitation kicks in.
Probably, yes.
Probably accumulates the heat (flywheel-effect)
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Hi, Ola!
21.2.2020
For how many seconds does your “bucketgas” last?
And how severe is your hearths delivery capability after the buckets are finished on "old"gas?
Does your acceleration die just after the bucket gas is finished?
How many seconds does it take to get the hearth fully delivering?
Max
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The old gas lasts maybe 10 seconds depending on power demand.
The severeness of the hesitation is not too bad. It’s very dependent on what kind of power demand - and the air setting of course. Worst case, I may still have 50-75% of full power with a rich enough setting. It last for about another 10 seconds and then the gasifier slowly recovers and I can start leaning the mixture again.
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Hi, J-O!
22.2.2020
Thank you !
Max
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Tried a few rounds of wood to test the new filter, the gas looks good the flame is not visible at all.
But what do you think about the filter, it looks like there will be a membrane on the outside, it looks to come off easily, when I shake a little on the filter it loosens like cookies, will it work in the car, or will the filter get tight?
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The last time I cleaned the unit there was very little coal during the narrowing, is it because I have too large pieces?
This will not work if I stand idle for a long time so the unit does not shake?
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Hi, Jan!
29.3.2020
May be, and a combination with too sloppy nozzletips…
Sloppy airflow does not break up chunks very energetickly…
While the air has an easy going to find suitable “channels” between “big” chunks.
A somewhat narrower nozzle-tips increase the velocity to the price of bit higher vacuum… and penetration.
If experimentation is high on the list of adventure, one could change the blow pattern of the nozzles:
The conventional pattern goes from a fixed perifery ring horizontally inwards to the center (linearly) .
That does not “flex” to the demand of gasproduction.
But Looking at the late 1950 Imberts from Köln, you see a wage strive to blow upwards to increase the process volume
at full blast! About 15 – 20 degrees uptilting.
Now, that is not the only way to increase process volume at full blast; the same “bending” out from the center can also be acheived by a degree of tangential “tilting”, thus increasing the process volume by increasing the active diameter of the glowing bed…
Max
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Jan,
I don’t know what kind of wood you used. If it’s those chunks you showed in post 109 I’m not surpriced. At least 4 times to big in my opinion.
Are they spruce or pine? It’s my experience spruce gives very poor char. Spruce burns hollow, turns to ash right away and leaves only a bridging skeleton.
For gasification I try to keep the % of spruce down. It’s a pitty since 95% of my slabs and edging are spruce.
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Thanks for the tips, I have 10mm nozzles, so I think these are in the bottom of what I should have.
Remember that my father said he made gas wood the size of a matchbox box, during WVII, so I agree with JO, that the pieces are probably too big as I have under item 109.
I haven’t used these yet, the bits I used are smaller, but a little bigger than a matchbox.
I have only run the unit with the fan, so I wonder if there is too much air in it, it gets too hot.
Have you run the unit for any length of time with only the fan on your unit @JO_Olsson
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If anything, the other way around. I wild guess is the engine pulls 10 times more air into the gasifier during normal roadspeeds compared to what my fan is capable of. Maybe with a vacuum cleaner you could get close.
If your fuel is already down close to matchbox size, maybe you’ve had some bridging going on. That would explain oxygene reaching deep down, consuming your char (and gas) and creating heat. Square fuel and no road vibration is the best recipe for bridging.
I never run the fan longer than it takes me to light up and add fuel. 2 min tops. Most of the time not even a drop of gasoline is needed to crank up and get going.
I’ve flared this gasifier only once, for 5 minutes, right after I built it.
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Thanks JO, I think I need to look at this before I mount it on the car.
Hi, Jan!
6.4.2020
To compare: Volvo 2,4L 3000RPM, 7% of “sekundenverbrauch” active hearth volume and half cigarett-pack size fuelbits. Goes 130 km/h constantly on motorways!
With horizontally blowing nozzles on one level.
Measuring pays off…
Max
Add for easy hearth calculating: Conical Frustum Calculator
Easy to set bottom and top, height and slope-angle…
This is my favorite to shape hearths… and their volumes.
Max
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@gasman. Oh, can’t you make a sketch of how you did it,with measure, so I can see what I did wrong and do right next time?
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Hi, Jan!
06.04.2020
Each motor has its own “circumstances”! You cannot improve one motors enviroment by substitute it with an enviroment designed for a different motor…
You have first to train to use conical frustum with “random” measures, and change them bit by bit, until the measures start to resemble something you aim at.
During each phase of change you can read the volume and the passage areas, how they change. Try to maintain 60 degree slopes all the time, because that is a “given” that you will need in the end.
As you have a bigger motor than 2,4L, it indicates that a
8% or 9%" of “secundenverbrauch” could fit the demand better.
Have you applied earlier descriptions of “gas consumpton per second” as described for example on Tom’s pages and other pages? And what results have you calculated?
Max
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Hi Max, I would like to see what a real unit looks like with dimensions and other, which is constructed by someone who understands this. I can only read and try, but there are apparently many ways to make mistakes.
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Hi, Jan!
07.4.2020
There is an old saying: “lazy man gets poor cabbage”.
First determine the gas consumption at optimum power for your motor at full throttle on open road, at highest gear.
l x n x 3
l = Liter of displacement
n = RPM : 1000
3 = all formula factors together
This results in net (netto) gas per second consumption when using 1:1 gas / air mixture.
(liters per second)
So you get the maximum gas consumtion at maximum speed on an open road on the highest gear.
This is easy, if you have a calibrated RPM meter!
From this you can determine the area and diameter of
of you restriction.
Flow m3/s
_____________ = Velocity m/s
Area m2
Flow m3/s
______________ = Area m2
Velocity m/s
You have to be sharp with the decimals!
1 m3 = 1000 liters = 1000 dm3
1m2 = 100 decimeters2
Choosing the restriction area for 2m/s gives a deacent performance allover the RPM - band for most motors.
When you have the restriction determined, you can start plotting the upper diameter for the hearth and the height.
Just look at the emerging “drawing” and correct for 60 degree slopes.
Everything goes well when you have the restriction diameter “to stand on”. The rest will form as the result tables tell you what to change in what direction…
The active hearth volume has to be chosen too!
As you change hight and upper diameter, the volume is also changing.
The result tables are promptly showing what you have done!
Changeing hight will also affect the upper diameter, as to maintain the 60 degrees of slopes.
My “guess” is that a volume of 8% of your “sekundenverbrauch” will work deacently.
Train and learn!
When this is established, comes the nozzles…
Max
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Thanks Max, as I see it, my mistake is that I only have 220mm diameter on the tube, should be 300mm.
Then it does not make it better because I have the nozzles so far down from the edge of the wood storage. I did so to get an edge so that the water does not go down to the hearth. What is “secundenverbrauch”?
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Hi, Jan!
8.4.2020
Sekundenverbrauch means cosumption per second; german way of turning consepts upside-up…
If your silo has a grater diameter than the firetube, it is more effective to have the gutter a bit up on the silo wall to avoid reboiling of the condensate. This reboiling also makes tar harder to remove… a dm or 2 up above the nozzles keeps the temperature more suitable to sustain condense water and flowing tar. No use to extend condensing surface downwards, if the result “goes up in smoke”…
I will have to revisit cone program…
max
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OK, I’ve tried to emulate this one, because it seems to work best (what I read) on moist fuel.
http://runeberg.org/tektid/1945/0827.html
Mine looks like this, and since I have the tube only 22cm, it can probably affect both carbon formation and that it easily becomes bridges. (I think)
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I wouldn’t worry too much about the firetube diameter. With small enough fuel (round limbwood if bridging) it should cover most of your driving up to 70-80 km/h. If you for some reason are in a real hurry you may want to add a few drops of gasoline anyway.
Oh, and where you have a 10 cm distance, I have only 3-4 cm. The entire funnel will eventually be covered with a mix of baked tar and debrie anyway.
Once you’ve been running things for a few months you’ll end up with a list of things you want to do differently no matter how many changes you do at this stage 
We’re using the same type hopper vessel. I’ve noticed the thin ss is always cold to the touch at the bottom. If you want to keep condensation from getting close to the hot firetube you could put a slice of a 25-30 cm tubing down there, as a barrier. Even without it, I think over time, a tar crust will form and keep the condensation insulated from the protruding firetube. A cold void at the drain perimeter is enough.
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