You made my day with the video. Looking at a sucessfull DOW feels like siting next to the person driveing.
I never questioned your builds performance, or eaven less your honesty. Like l sayd before, since we have nearly identical hearts (well gasifier and human l guess ) and similar displacement motors it is a great platform to compare things like preheat, hopper condens, gas reseroars etc.
So, based on what l have seen, and to compare, l can allso idle for about 10 min before the engine starts to calf (gasifier too cold for good gas), but it is your driveoff that amazes me. I cant do that.
I think the main reason is you have a 100l (?) Hayfilter, and a big condensation tank, + big cooling rail, so a WAG about 150l of gas ready to feed the engine. Thats 10s fof driveing at WOT for you.
I have a gas volume of all together 15l . This is one sole second of driveing and it just isnt enough for a smooth driveoff. Plus, l have a automixer so l cant reachen the gasmix.
This is why l hit the hybrid swich at a traffic light. If the idle is less thain about a minute, l usualy can driveoff without hybrid, but l usualy hit the swich to avoyd potential accidents of stalling in a crossroad.
Its sad to look the sun go down at 4 pm here, to have 4 hours less sun per day must realy be depressing…
Ps How long do days get in the summer up there north?
Thanks Kristijan! You are good with words. I’ve had more than twice the time to practice but still struggle to dress my thoughts in words.
Close. 120 l.
Yes, that volume is very helpful but will also hold 120 l weak gas if the gasifier runs too cold.
We are lucky to be able to use that boost switch from time to time. I do have a red safety cap on mine though. I would hate wasting gasoline by accident
Over all we seem to experience simular performance.
Any news on your new restriction?
I don’t live far north enough to see the midnight sun, but there is daylight all night. The sun hides right below the horizon for a couple of hours.
Edit: Does your car ever run rich when running woodgas and hitting the gasoline switch?
Its true, the DOW sets in your blood so fast you pitty every shot worth of petrol to be burnt
I allso look often on the swiches just in case l wuld accidently hit one
Yes the restriction runs well. Great in fact. Al thugh its main purpose now is get rid of tars, the flyweel effect is yet to be worked on. Thanks for the concern.
As for hybriding, the anwser is no. Atleast not if l hit the 25% petrol swich. If l hit the 100% petrol swich, the engine stalls.
I think the automixer is in my favor here. In cases l make lean gas, the gas still mixes with air at 50/50 ratio. Lean gas means less combustible geses per same volume, so there is some O2 left in the 50/50 mix for the hybrid mode to work without adding more atmospheric air.
JO, your rabbit does have a lambda right? Have you ever hooked it up to a voltmeter while DOW? What does it show?
Myne shows 0,05v at lean gas and 0.13 v when the gas is good. The power is good, but the voltage shuld be closer to 0.4v by the book.
We talked about the north daytime over dinner today with my family and we cant seem to decide if its good or bad. The conclusion was we wuld most likely work our selfs to deth in summer and sleep our selfs to deth at wintertime but l guess one gets used to everything.
Lambda - yes. Voltmeter - no, I’ve never tried that but when hybriding I can run with the air valve wide open or squeeze it to where killing the fuel pump doesn’t affect power. It seems my old fuel regulator isn’t very picky on range. It operates on lambda signal only and output can be anything from 0-100%.
This adds to my list of experiments I want to do. Maybe that signal can be used permanently as a primitive air/fuel ratio meter. What do you think?
Yeah, something like that You better believe in reincarnation.
Anyway- every spring is the beginning of a new life.
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.
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
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.
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.
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.
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?
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.
) and similar displacement motors it is a great platform to compare things like preheat, hopper condens, gas reseroars etc.
