So, if l get this right, the “computor” regulatrs a valve before the fuel nozzle based on the info from the lambda and air mass meter. Clever. And simple!
Did you brick your air meter somehow?
Did you mean like a a/f guage or like a lambda based automixer?
Well, almost.
The fuel pump feeds a small “pressure tank” in the motor compartment. Constant system pressure is maintained by a spring loaded return valve. It sends the access fuel back to the fuel tank.
The air flow meter plate’s arm pushes a plunch that lets fuel through to the spring loaded fuel nozzles according to air flow.
That’s about all…
…but…
…newer cars 
like mine (1989 and forward) also have cat and lambda.
The lambda signal is used only to fine adjust main system pressure in order to keep the cat happy.
Running woodgas in hybrid mode requires a bit more than fine adjustment but it handles that task just fine.
No, it’s left as is.
Only time I touch it I put a stick under it to simulate airflow when burning my intake.
A/F guage.
I’ve had my Stihl for 10 years and have only replaced spark plugs and recoil rope and spring. Great power, good balance.
Oh, yeah, blades too, of course.
Cold weather obsevations:
Today, at -15 C, my hopper juice was finally frozen. The plastic can was still soft and could be squeezed but nothing came out when I turned it around. I put it in bucket of hot water for 5 min and that did the trick.
Post gasifier condensation is down to tablespoons ever since I scratched the baked tar away from under the funnel. Hopper cirkulation really dries the wood when cold.
Startups, no difference. Less than a minute of blower running + less then 100 yards of driving when the fuel pump is turned off.
Hayfilter. This was what worried me the most. I expected ice buildup, but no problem so far.
Today’s distance: 50 miles, 99.9% woodgas 
PS. Close to 6 months since I poured any gasoline into the tank. It might start to rot
Hi, Jan-Ola!
19.12.2016
Now, a side-track suggestion for the silo/ashbunker varying pressure-ratio between
“small” driving and full “long” driving: Rise the restriction! First 1/2", then 1/1"!
“The small driving” collects char, the long hard drive “consumes” the char…
Reason: Too much is “happening” in the upper part of the hearth!
On full blow, you have to “push” the bigger char (as long as it is reasonably big)
down into the reduction part to extend the process time and process surface,
the low power needs a smaller upper volume anyway.
Max, thanks for your suggestion. I might try some experimenting in the spring if I’m still up and running. Winter conditions make me less keen on playing with a working unit.
I DOW every day and I actually belive I’m about in the middle of my needs. 9 trips outof 10 my vacuum ratio stays between 3:1 to 4:1. Performance is the same from 2.5 :1 to 5:1. However gastemp climbs more easily if down to 2.5:1, but as long as I stay below 80 km/h (50 mph), out of cyclone temp stays between 150-200 C (300-400 F).
Constipation symptomes are only seen if I happen to grab a bag of very small fuel and do low end driving with several short shutdowns. I think this is mostly due to ash buildup in the lower region. Easily corrected by tappning or turning the grate a little bit at refueling or next lightup.
Hi, Jan-Ola!
20.12.2016
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)
Despite being a “cold air Imbert”, strongly blasted and having a too tight “grate”,
really a small-hole sieve plate, it behaves excellently in town and on the road.
It has to be modified with caution… beginning from below.
Hi, Jan-Ola!
20.12.2016
Usually gasflow in the reduction zone, beginning from the Imbert “expansion cone”
has always been treated as a linear (one direction) flow.
We are accepting that nozzle-beams activate recirculation paths in the oxidation zone.
The same thing happens at the restriction blow beam, straggling but still happens.
When the upper and lower hearth is the same continuous pipe, parted in two by the
the restriction plane, there is an excellent return path for the reduction gases upwards
along the cylinder walls and bending in towards the “restriction beam”…
To be successful, the reduction-cylinder walls have to be doubble-walled, filled with ash, etc.
to keep the return gases at active temperature.
This vertical recirculation of reduction gases in a broad reduction tube
(same tube as for oxidation) keeps the char “process-hot” and instantly ready
for full blast after idle!
This has been a problem for many gassers: Weak responce after traffic lights idling.
(Kristijan, for one, if it is not the mal-precision dispenser)
“Audi Imbert” starts as a “rocket” from traffic lights. No gasoline on board, EVER.
Max,
Interasting prospective. But l dont understand some things.
You are saying a part of gas leaveing the reduction zone returns back in the reduction char?
In my case l fit all yout suggestions, the distance from nozzles to grate is separated in half with the restriction plane, and the whole firetube is double walled insulated with tightly packed mineral woll. So, in your opinion, where lyes the problem?
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 (half the cylinder volume of gas, every other stroke, times rpm/60). That’s 26250 cm3/s.
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?
Kristijan, I think Max referes to the blast from the restriction creating like an upside down atomic bomb mushroom. Gases traveling upwards close to the reduction wall.
JO,
I think its (rpm:1000) x displacement x 3.
3x1,8x3 = 19l/s.
This gives you 3% roughly. Ok its time l do some calculations my self
Edit what restriction dia do you use now?
90 mm is my restriction dia
Edit:
I read on a swedish gengas site you need 100 L/s to develop 50 hp ???
Maybe I do it wrong too but I also use X .7 cylinder fill ratio which brings it down to 18375 cm3/s
Ok l got the active cone/gas flow ratio of 10%! A first thing to change!
Thanks Don! That confirms Kristijan’s 3%.
JO, l think thats 100m3/h for 50 hp.
How did you come up with that number? Our hearts are supposed to be similar.
Yes, of course. Sorry about that.
Nozzle diameter of 18cm, nozzle to restriction plane 12 cm, restriction 10cm. This gives 1.8l cut cone volume
Whats your nozzle to restriction height?