Thank you Jan! I like the tennis ball!
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Can’t take credit for that idea.
That’s Wayne’s signature pressure relief valve 
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lambda sensor regulates the injection pressure? (lambda ypically regulates the duration of injection)
no air flow sensor?
what year is your rabbit?
I love old things … I feel less obsolete with them:grin:
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Thierry,
This is a constant fuel spray Bosch system used by VW, Mercedes, Volvo, Saab and others since the early 70s until early 90s.
A mecanical air flow plate dictates fuel pressure and late years (1989 and forward) cat versions use lambda as fine tuning. Mine is 1990.
I guess my lambda does not only do fine tuning these days. I think if I sqeeze my air valve enough, driving woodgas, the gasoline delivered is zero - fuel pump still running. Perfect for hybriding.
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Hi Jan-Ola, how do you do a carbon build up clean out on the intake and throttle plates of the rabbit truck? It’s throttle body injection system on it. Right?
Bob
No, it’s mpfi but constant spray. Only difference is I have to manually simulate air flow to get fuel to the injectors. The air flow meter (plate) is on top of my airfilter and can be lifted manually.
Edit: The big black rubber to the right in post 520 is the air flow meter’s housing.
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I sorry I do not understand well
you said “I think if I sqeeze enough my air valve, woodgas driving, the gasoline Delivered is zero -. fuel pump still running”
if “sqeeze” air valve enough, gasoline is zero … ok with that.
but from where comes the mixing air for woodgas in the engine ?
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Air is still added, but restricted to the point where the lambda starts to sence no oxygene in the exhaust (rich enough mixture - no fuel needed).
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In North America this Bosch style of fuel injection was named Constant Injection Spray - “CIS”.
The up to 100 psi fuel going out via braided high pressure lines to each individual intake runner ports. Each injector tip there with a pressure opening valve like the 1990’s GM plastic spider lines systems.
Bosch CIS was used on USA VW’s and Porsche’s from the 70’s up through the late 1980’s. Later systems DID incorporate in an exhaust oxygen sensor feedback “trimming” circuit. Early non-oxygen sensor systems had no computer and were all electrical-mechanical.
This same system was used a lot by Toyota under license in the late 70’s and 80’s.
Oxegen sensor system the computor was very simple for just a pressure trimming control. Then added a Baro(meter) pressure sensor computer input or altitude and weather changes fine trimming too.
Increasing demanded OBD 1, then OBD II regulations, by the nanny-state’ers and ever-goals-changing eco-tech-geeks for mandated on-board self-diagnostics; and continuous self-testing systems killed off all of the earlier, simpler effective FI systems from all manufactures. Comply: to be able to sell into the USofA market.
Grumpy 'ol Steve Unruh
(Ha! Ha! KristijanL part of the “library I ate” was back in the mid-70’s in my 20’s in the Robert Bosch technical training manual series. Back then NO easy scanners. Had to know the systems design parameters and characteristics and then pin-point VOM and oscilloscope test/troubleshoot all problems.
I still read manuals weekly. 52 weeks times 45 years equals a lot of manuals eaten. S.U.)
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Jo thank you for the clarification
This system “constant fuel spray Bosch” seems to be ideal for the hybrid driving!
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Nice Jo, very nice. Works perfect! Congrats!
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Hi JO,
What a nice ride, felt like I was at home. I liked the instruments shots and explanations along the way and the oops in the circle got a smile. Well done.
Pepe
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The Rabbit ran just fine Tuesday when I recorded the film and I was about to mention that the gasifier seems to have gotten imune to constipation lately.
Yesterday I grabbed a bag and happened to get old small chunks from last year. I drove 12 miles into town and started to see higher ratio, around 6:1 before I parked. On my way home I ended up 10:1 and higher. I gave up and drove last few miles home on dino.
Those of you who watched me trying out my rebak chunker last fall might have noticed I poured my chunks into the corn cribs green. I thought the ventilation should do, and it just might in dry air spring time, but doing this in damp fall was not a good idea. The small chunks have mold on them and some are even a bit soft and mushy.
Lit up really low today and even tapped my grate quite hard with the poker while burning, filled up with stiff bigger chunks and went for a short WOT race. Back to normal in a couple of miles.
I have a tiny charbed, quite easy to straighten out, but those of you who have huge ones might want to avoid too much soft, mushy wood. I guess it will all turn to fines.
Wood drying process should be as quick as possible.
Just my 2c
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JO, with mushy wood you mean punky/rotten and thain dryed? If so, this represents about 1/3 of my fuel by volume. I burn very old oak firewood, with its white wood (dont realy know how this is called in english, its the white unquality wood beneeth the bark) about the consistancy of styrofoam. Never had a problem now that its all set up well. the only problen l see with it is that it is bulkyer thain the quality premium wood.
Are you unable to drive with pressure ratios that high?
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Mushy. Yes, kind of half rotten before properly dried.
I’m not familiar with oak wood but I think my mushy alder and birch wood turn to fines and not crunchy charcoal.
When I see 10:1 I can drive maybe 50-60 km/h. I easily peg my vacuum guage at that ratio and have to be careful not to invert my plastic hay filter . 40" H2O is a lot of force on a large surface barrel. The ratio worsened even more so I decided to shut down.
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KristijanL in the english language (by woodsmen) the white outer wood is called “sapwood”. This was the alive part still able to pass up and down sap (pitch) tree-blood.
The inner dark part is called “heartwood”. Technically dead. But gives the tree the strength core to stand/grow tall and proud, resist winds and snows loading’s.
Bowers (bow makers) would use the characteristics of these two layers in their bow making staves for compression/tension benefits.
Oh. Here the wood eating larva of the Carpenter ants hole-bore eat through the sapwood layer in newly downed and died trees. Leave the dead non-nutritious heartwood alone.
S.U.
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Sapwood, got it. Thank you.
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A couple of months back I promised Max I would check out my tach. A work mate of mine happend to have the proper aquipment. Now it’s done.
I claimed 2500 rpm at 100 km/h. The truth is +5%. I also checked out my speedometer. The gps shows -5%. This means I rev 2625 rpm at 95 km/h (about 60 mph) in fifth gear.
On woodgas the Rabbit likes 80 km/h (50 mph) at 2000 rpm best. I know now that’s more like 2100 rpm and slightly slower.
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Interasting, it seems you have lower gas demand for the same output as l do. 80kmh is allso my cruze speed, but l get that at 2800 rpm.
JO, your mushy alder got me thinking yesterday. I threw apart my wood pile and picked out the mushyest alder l culd find.
all the white is styrofoam quality, and the red isnt much better. Chunked it and went for a ride. No obvious difference.
Since we have such similar gasifiers and engines where do you think is the difference?
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I don’t think we know anything about gas demand. Your numbers are my numbers if I shift down to 4th gear.
Sensitivity to fines might have to do with the grate. My reduction is picky on fuelsize although power is about the same from 2:1 to 6:1 ratio. However 90% of the time I see 3:1 to 4:1 wich is perfect.
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