Haha! My bad again! I shouldn’t really tell what I did…
…but ok…
…I calculated heart dia in cm, but hight in inches 
If I remember right 4,5" (11,5 cm). About same as yours.
Your 10% confirms Max’s earlier suggestion that my oxi volume was 1.7 times optimal. I was running the 3" dia insert and 4" restriction to nozzle hight at the time.
Hi, Jan-Ola & Kristijan & Don!
20.12.2016
My old 1983? formula for NET gas consumption:
L X n X 3 =
L = displacement in liters … (case bound)
n = RPM:1000 … (case bound)
3 = unmovable factors “summoned”… (stationary, not case bound)
…
…
Case bound … Stationary
…4-stroke factor X mixing factor X filling factor X transported 1000
L X n X … ___________________________________________________ = 3
… 60 (from minute base to second base)
… 0,5 … X …0,5… X …0,72 …X … 1000
1,8 X 2,5 X … _____________________________________________= 3
… 60 …(from minute base to second base)
= 13,5 liter net (netto) gas/s
Haha l shuldnt realy laugh either l spent the last half a hour shooting at shadows too in terms of reintroduceing my brain with math once again
Ok conclusion? Our hearths are too big 
Now we have a problem. If we set the restriction higher, we loose the 60° char slope. So, we have to make the nozzles longer. Myne are screw in but the question is wuld the protrudeing nozzles affect the bridgeing of wood chunks?
Allso, if l remember right, the reduction zone shuld by the book be one third of oxy. So thats just about 400ccm?? This seems aufall small…
@gasman, wuld you be so kind and show us your heart dimensions? I think you did before but cand find them…
I don’t think so. A 60 degree slope only climbs about 8cm with our restriction and heart diameters. Hm…the 400 cm3 sounds like fire in the dump.
Ok then. I tryed building “by the feeling”, now lll make heart dimensions “by the book”. Lets see what happens. Ill report the day after tomorow, tomorow is a big day, two 300 kg pigs to put in the attic and freezer. Althugh this debate fired my curiousity to a point l might set the dimensions today.
Fired my curiousity too. Springtime it is
Hi, Jan-Ola & Kristijan!
20.12.2016
I lost my text size and can hardly see any text. I don’t know how to resize back the normal text size.
Desktop and ff page (google) are normal, only this Forum page is gone mad!
I don’t know, if somebody has payed me a joke or what is going on!
Press Ctrl-0, Max. That’s a Zero not letter “O”.
That will reset the zoom controls.
Wondering how I did that? Like this:
<big> Some really big words.</big>
Hi Jan-Ola & Kristijan!
20.12.2016
There is no established rule over the oxidation volume; it is up to estimation,
In Sweden, during WW II the big trucks and busses with 7 – 11 liter motors
and beer-can sized fuel used 11% of the “second consumtion” as the Germans
express it!
Sekundenverbrauch!
DJ used 4% for his small grass clippers, and so on…
With a commercial volume calculator it is easy to “nail” the cut cone volume:
Hope this easies the estimations!
I was earlier describing the reduction in a long cylinder making both the oxidation
and the reduction with just the restriction plane in between them.
As the diameter is about 2 - 3 times the restriction opening, the down-blast will
activate an up circulation along the side-walls back to the blast beam…
Max,
Is this upblast cosiderable? The reduction char cone in my gasifier is surrounded with a mix of charcoal/dust so l dubt much gas can break trugh that or am l missing something?
Have you got any suggestion on preffered reduction size?
Hi, Kristijan!
20.12 2016
In a wide cylinder with unclogged char it would be modest, in your case it seems to be
non-existent, as it looks more like a straight tube in the char down to the grate-slots.
No, the decisive factor seems to be the free outlet area in the grate.
A wide, lazy grate needs mechanical action, sieving or shaking to allow flow through.
A grate with smaller passage area ~about the restriction area, is completely dependent on
on high draft as on open road, and starts clogging in town traffic.
If a grate is not only letting gas and ash through, but like in Imberts, letting the gas
out sideways, the clogging is not as much a short period problem.
The “all through” type is more critical. It also works better with smaller reduction volumes,
which can be kept cleaner from settling ash. More like the type you are using.
But trimming is critical and needs more attention.
Hi, Krisijan!
21.12.2016
Hearth tube DI = 210 mm
My oxidation is ~950 cm3,
5% of 19 l/s
Nozzle-tip-circle 160 mm,
4 nozzles, hole diameter 8,5 mm
Silo funnel makes a ringbalcony abowe
the nozzles for sucking and collecting
pyrolysegases
Max, what about reduction volume? (dia/hight)
Hi, Jan-Ola!
21.12.2016
Vast! Full diameter. ~420 mm X 30 mm from “grate” up to the lower end
of the 210 mm tube. = 4,156 liter.
In the tube 210 mm X 100 mm. (upwards to the restriction plate)
= 3,4636 liter.
4,156 l + 3,4636 l = 7,6196 liter.
There is more (insulation) char outside-upward the 210 mm tube!
Works well for 700 – 1000 km,
when it is time to shake and clean out the low ashbunker.
The good part is, that it does not behave differently on any power level.
Fast response from idle to WOT! No delay time.
Still, it needs an angeliron grate!
Hi, Jan-Ola!
25.12.2016
A late answere to dec. 20 mess. 651:
Jan-Ola Olsson (SWEDEN)JO_Olsson
5d
1
gasman
Just for reference: The Audi "Imbert" has only 5% upper hearth volume (cut cone) of the net gas consumption per second at WOT on motorways! (3500 RPM)
I’ve never done any calculations, but now that I do they suggest my gasifier is almost down to 2% ???
I did it this way:
1800/4×3500/60
That’s 26250 cm3/s.
(fault half the cylinder volume of gas, every other stroke, times rpm/60 fault).
That is so far one cylinder full filling/s, each stroke.
Divided by two for 4-stroke, and by two for 1:1 mixing
26250 cm3/s : 2 : 2 = 6562,5 cm3 net gas/s for one cylinder.
4 cyl. X 6562,5 cm3/s = 26250 cm3/s
Times a realistic filling factor 0,72 = 18900 cm3/s!!!
For all cylinders together…
Why not use the practical formula:
l X n X 3 = ??? Every stationary factor is there, you only
need to give the displacement and n = rpm:1000
…
My upper heart (nozzle tip to restriction) cut cone volume is 556 cm3.
556/26250 = 2.1%
What did I do wrong? What’s the proper way of calculating gas consumption?
…
556 cm3 : 18900 cm3 = 2,94179% ???
I still doubt that…
Have you used Conical frustum calculator?
(Observe they want radius, not diameter)
Hello Max,
Read a few more posts and you’ll discover I was the one that messed up my calculations.
I was fast, but wrong. I accedently punched in the cone hight in inches.
Kristijan and I finally came to the conclution we both had an upper heart volume of around 10% of “sekundenverbrauch”.
Hi Jan,
You mentioned you dont touch the a/f valve at all while driveing.
So, you set it when you startup and thats it? Idle, highway, all the same setting?
Yes, that’s pretty much right.
I squeeze it when I pull gas up to the motor. When out on the road I might try lean out to where I feel I’m starting to lose power and I back off from there just a little bit.
Edit: When pulling really hard, climbing a steep hill, I might try richen the mixture a little bit.(I know I have some small leaks in the hayfilter rubber fittings that will show at hard pulls)
Ok got it. Thats preety cool. Seems not much more work thain with aautomixer.
Im thinking to go back to cable. The automixer is very picky on gas quality. I think if l culd set it richer in city l might just get away without pressing the hybrid swich so often.
Hi, Kristijan!
26.12.2016
Actually, the autodispenser is not picky, provided that both flaps
are opening perfectly identical!
I have made several of them, and had no trouble
with either small or big ones!
Perfectionism in this case is rewarding in a grand way.
0,5 mm versus 1mm at opening makes a mockery of whole the
ratio demand!
They have to close and open identically, absolute! Basta!
When closed, you shall not see sunlight through either throat.