Hello DJ,
WOW!!!
All I can say is if I was out showing one of my wood burners and you pulled up beside me I would go hide.
Thanks all for the kind words. Hey Mr. Wayne, it being so shiny does not mean it works better than your systemā¦ Besides that, after this intense and time consuming project, I am ready again to play with junk materials.
Regards,
DJ
Right,
Maiden trip was yesterday. As usual with prototypes, building is only 80% of the job. Now starts the hard and deep thinkingā¦ Results were mixed. Frequent backfires from the intake manifold told me something was wrong with the mixture. The vacuumcontroller is probably too small and therefore not accurate enough. After removing it and running on manual control, starting and driving was a piece of cake. But weāre not at the finish yet:
-Gas is way too hot. Cyclones are golden brown. I have an internal leak at the ashport (white spot in the carbon dusted walls), but difficult to get rid of it. Lowered the grate to maximum. Further is possible, but asks for taking the gasifier apart. Channelling is also a posibility, why the gas is so hot.
-Gas is white smoky. Yet the car runs well on it, but I like it to be pale blue. Together with the high temperature this could mean some tweaking in hearth dimensions is necessary.
-No soot or tar deposits to find behind the throttle. Only dry carbon dust.
-Damn, is it fast, despite an internal leak and no ignition advance. It is low geared, so 3,000 rpm means 70 mph. Didnāt drive faster yet because of the danger of overheating, but more is possible. Acceleration is very good. Idling is smooth.
-Startup time is very short, only 2 minutes.
-New grate does very well, no stirring necessary.
Input on the smoky and hot gas are welcome, so far never had any problems with that on previous gasifiers.
Pic of adding the filter/cooler assembly:
Hi DJ, Perhaps more heat recovery on the gas leaving the unit? Not sure what you have currently in that department.
absolutely beautiful buildā¦ dang
Hi DJ
I was going to ask about your fuel used; then your picture showed me well.
āI thinkā your cooling assembly is far too inadequate for the amount of heat you need to shed off for this size of system.
Even after you correct your internal hearth problems āI thinkā this will prove true. SS is less thermal transfer capable than standard carbon steels by a strong %; 21% less I recall. You will need something 3-4X the size you had on the Volvo.
You could verify this by external water spray and forced fan air cooling your existing cooler to confirm this.
Hey, nice roof line on the house/shop. Dual seasonal capable.
Regards
Steve Unruh
Hello DJ,
Nice looking vehicle!!
When I build a new gasifier I save about ten gallon of ash and char from one of the other trucks to pour in the gasifier before start up. Vibrate some of it down through the grate to coat and insulate the ash dump. With this procedure the gasifier will usually burn clean within a few minutes.
On my latest truck I wanted to show how to get it primed with out using the ash form another vehicle.
I bought a bag of charcoal (natural) and put in the gasifier. It wasnāt enough and only brought the level near the nozzles and was very coarse. I also added wood on top.
I had to cycle the gasifier several times before the gas was ready for the motor. I would fire the gasiifer up and get it hot and wait a few hours or the next day and repeat. It took about ten cycles to get the gasifier burnt in properly and eliminate the white smoke and burn clean.
My latest truck seems to run cool, the highest I have seen the temperatures coming from the gasifier into the cooler is 350 F and I was pushing the truck at speeds that was dangerous and illegal. Cruising at about 60 mph it holds about 250-300 F.
My trucks are geared quit high. On the Dakotas 2000 rpm = 65 mph. On the ram 2000 rpm = 75 mph
Nice work and please keep us posted.
Hello Mr. Wayne,
I recognize the bbq charcoal problems. Some hard clumps do stay a long time in the reduction zone before they disappear. Had that before. Iāll dig the gasifier empty to have a close look.
Steve,
Cooling should be sufficient when the gas leaving the gasifier would be like or lower that the Volvo. Total cooling surface is about 3 times the Volvo. And yes, wood is not the only energy source here. Negative electric bill with 4.8 kWp PV and 800 Watt home made windturbine. Next winter we will also be cooking on wood. Next year full home heating on wood. 10 gallons of gasoline a year for the chainsaw will be all Dino fuel we need thenā¦
Hello Chris,
An extra preheat mantle would do no harm. Back to the drawing tableā¦
Regards,
DJ
Hello DJ,
David S. here to formally introduce myself. We have not chated before, but I will chime in with the rest of the group and say nice work. I am also building a stainless unit that I have been working on for a couple of years. Obviously I donāt stay at it steady. Its home will be a 4 cyl toyota truck. I like how you kept your unit very compact on this truck. I was however looking at pictures over on your site of the volvo build, and had a couple of questions if you donāt mind?
I will not be able to keep my unit as compact as you did do to the box being very close to the frame, and a gas tank being in the way on the other side. I could just remove the gas tank as that is the obective right? Anyway, what size motor does your volvo have, and how did it perform with what I will call all the wind catching stuff on hanging on the back namely the gasifier?
I will end up above the cab a fair amount with my hopper due to my mini pickup being low profile, and am concerned of wind drag, although we are dealing with cylinders here and they are somewhat aerodynamic.
Again nice work on your stuff. I really appreciate that you are sharing with all of us what your up to.
Thanks
David S.
DJ, It is strange how putting recovered heat into the primary air cools the exiting gas ā¦ Hope you find the air leak that may be wasting your gas ā¦ Mike L
DJ, Oh, Could you send me your cyclones ??? Thanks, Mike
David,
Excuse me for the delayed reply. Not sure where your gas tank is, so I cannot answer that question. I like Waynes approach to stay above of the frame. It is less complicated and does not compromise the design. Drawback is either a small fuel bin or a high gasifier.
The Volvo has a 2.3 liter engine. It is low torque and even lower by using a camshaft of a turbo engine. It has less overlap of the cams. A Volvo 240 is nicknamed ābrickā, so it catches wind anywayā¦ The gasifier will add to the drag, but itās weight seems to me more of a problem, certainly when you are surrounded by hills.
Steve,
You are right on the cooling. I took care of the internal leaks and modified the air preheat. Gas temperature is lower now. Dew point will be somewhere between end of the precooler and early stage of the filter. The cooler not being in direct wind does not help much either.
I also took care of a new, bigger vacuum controller and placed it so that it is not affected by braking or bumping. Works well. Driving without controller askes for frequent manual adjustments and a soft right foot.
I added gas reheating in order to keep the mixer and intake manifold dry. It is a simple tube in tube heat exchanger. Some of the exhaust gas of the left hand exhaust pipe is bypassed to the reheater.
Now Iām testdriving, tweaking and making small changes. Wet filter does what I expected: the condensate after the filter is clear. Which does not mean the gas is ultimately clean. Dry carbon dust can be found after the throttle/mixing valves. This powder can only be prevented by dry filtering. But that is a choice between ultimate filtration by sensitive materials or less filtering by means of fool proof material. The gas is absolutely tar free. Not even an oily tang on the filter/cooler condensate. No smelly black fingers this time.
Fuel consumption seems about double of the Volvo, which makes sense, because on dino it also uses the double amount. On the Volvo I can go as low as .65 pounds to the mile on long distances and 1 pound on short tracks and city traffic.
Pics will follow soon. I am repainting the car for now. The sound of the car is wonderful. On LPG or gas the Cherry Bomb mufflers sound harsh, but on woodgas the noise is softened, but still dark. It even pleases femalesā¦
Regards,
DJ
Took the beast to the motorway today for a performance test. The vacuum controller gave some trouble, because it choked the air too much. Apparently the membrane is stretched and giving a floppy control, same as the previous smaller one, which worked well on the Volvo. So I drove without choke, not even a manual choke, but with a very tender right foot.
Performance is good enough: 82 mph. 0-60 in 32 seconds. 0-30 takes more time than 30-60. For me an indication some gain can be found in adequate mixture control at low rpms. 82 mph corresponds to about 3,500 rpm. And I still havenāt ignition advanceā¦
Regards,
DJ
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Hi DJ
Nice paint job. Color helps blend in the gasifier.
Your gearing just like your answer about hopper capacity is a choice. You still want this to be a pulling farm truck also, eh?
Once your paint has all summer to hardened up good I would still suggest 100-150 mm pieces of acrylic wool yarn removable painters taped all over so you can actually see the air flows and turbulence zones. Amazing the difference just dropping down the bed tail gate can make.
May be an air flow shaping deflector wing at the trailing edge of the cab like on the front of older European RR locomotives could smooth out and increase your cooler tubes air flows.
Regards
Steve Unruh
Hi DJ,
I am curious about the total weightā¦and the gear ratio. Looks really amazing !!
Gary,
I donāt know the gear ratio, I just compared speed to rpm. Took a temporary rpm clock from an other car. The speedometer is correct, if the radar speed checkers along the road are correct too. Weight of the gasifier system is about 350 kg.
Steve,
Already read somewhere that a dropped tail gate reduces fuel consumption. I might add a kind of wind catcher for better cooling. But only if the gained efficiency wins from extra drag. On the other hand, if performance, handling and gas quality is good, why try to make this an fuel efficient car. It wasnāt from the beginning, 40 years agoā¦
Still, it amazes me that this relatively large engine can run 3,500 rpm on full power, without ignition advance. Myth busted? I doubt it. Need to work on ignition advance.
Regards,
DJ
Hey DJ
I like the way your planned through the back window gauge viewing gap in your system has turned out.
I am sure your second primary drive will like on this one, the ability to see directly behind for backing up.
And you for the trailing speed police.
You are already bumping into Vesaās speed/time performance numbers he has published for forced induction super and turbocharged woodgas fueled small block V-8ās.
Ignition timing: you should already have a total of ~44 degrees BTDC above 2500-3000 engine RPM on an this at least 8.5 to 1 compression engine. Surly better than the 10-15 degrees fixed you only have on most small engines ( many valve in block below 8 to 1 compression) - part of the source of the myth I am sure.
One of the India Institute of Science papers Chris Seanz put in the PDF resources here states that Good composite woodgas has a ~30% faster burning speed in comparison to methane/propane. Their in Lab works then compared to out in the field deployed systems in the last 25 years has collapsed many of the carry over woodgas myths.
Primary to some of these myths I believe is taking 1930ās thru 1960ās slower speed flame front charcoal and coke gasifing (high CO, low H2, NO CH4) experience in low compression long stroke engines and applying it to faster flame front good below 50% N2 composite 15-20% CO AND H2, and always 1-4% CH4 raw woodfuel gas out of the more modern developed systems in then higher compression short stroke engines.
Easiest quick way to tell on your current system set-up would be to hand pump suck on the distributor vacuum advance at your 3500 rpm under a load. Should be good for another 8-10 degrees of crank shaft advance.
Regards
Steve Unruh
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DJ
Could you elaborate a little more on how you do the bushings and rods and attach the valve flaps to the rods. Also you said you use copper water pipe for your bushings. Are you making these a press fit somehow into the steel tube. Details like those would be appreciated.
David S
Well David, the assembly is done with oridinary DIY tools. I do not have a lathe, but it would improve the quality of the work.
The 12x1 mm waterpipe already fits tight over the 10 mm rods. Drill two 12 mm holes in the throttle tube, stick the copper waterpipe pieces in and align them with a 10 mm rod. Braze the copper pipes to the throttle tube. One end gets an end cap brazed over the tube. You can add a grease nipple to the end cap. Where the flaps are fixed to the rods, you file a flat spot on the rods, just like a conventional carburettor throttle valve. Drill the two holes in the flap (for connection to the rod) a bit wider. Tighten the screws while pressing/aligning the flap to the throttle tube inner wall. Lock the screws! You do not want one of them eaten by the motor.
Regards,
DJ
Thank you kindly DJ. I guess I never though of just fileing a flat spot on the shaft. I kept thinking I had to put a slit perfectly in the middle to slide the plate through and then drill and screw it. I got one done today. I made a stainless 14ga disc with a 2.5 inch hole saw. It fit nice inside of my 2.5 inch stainless tube I am using. I filed the flat spot on a brass 1/4 inch rod, drilled my holes in the disc and shaft, and drilled 1/4 inch holes direct accross from each other in the tube and bingo! I think I will get some or make some small 1/4 inch SS bushings I can tig tack to my tube for guides and I will have it. Then on to a second. Oh and I wonāt forget the locktight on the screws.
Thanks again for the input!
Grateful from my side of the pond!
David S
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