Probably tru with a low turbulence gasifier which is big enough to never pull through + combined with a huge dropbox.
That’s however out of the question. I never thought a system could run as cool as this one does. Below 80 km/h I hardly reach 100C at the heatex outlet and the second half of the cooler maintains ambient temp.
The tar I mentioned is harvested in the hopper condensation vessel.
The positive system pressure lasts about a minute or so after shutdown and woodgas vents out the motor’s air-filter. No extra vent installed.
Yes, first weeks of running the gasifier, with not enough ash insulation, it ran too cool and some tary fumes passed the charbed.
As with any gasifier the amount of char consumed increases with the woodgas consumed. With a lot of short trips and slow driving, some char has to be slipped past the grate and wasted in order to make the charbed breathe well. This rig is probably best suited constantly running 90-100 km/h. Not much char would be wasted then.
Tone,
You have to keep in mind what Tom (I think it was) once wrote about JO. It was something like this: “I bet when you go fishing, the fish jump into the boat.” He seems to have really good luck.
Steve B., I see it differently, a lot of knowledge and experience is concentrated in this system, the shape and construction of the hot zone, the installation of nozzles, heat exchange between intake air and gas, condensation of water vapor, … and of course installation in the vehicle, … hat down to the master,.,. and finally the system management. Bravo Jo, keep letting your fish jump into the boat.
I talked to Niklas yesterday, he told me that Imbert had a table on how big pieces of wood would be in, in relation to the choke.
Maybe you should try som hoppers with smaller pieces, maybe hesitation disappeared?
I had my suspicions this was a factor, the first size I’m going to be running in the Joni copy for the Mazda is going to be jenga block sized pieces of red oak.
Just a few things I think will help with hesitation.
More mass at the bottom of the gasifier . Heavier choke plate and steel.
More storage capacity of the gas. Heat exchanger / drop box , condensation tank , more and bigger cooling rails , hay filter , more and bigger piping going to the motor.
Flywheel effect .
Careful not to have to much storage in one container for safety reasons. Better to have the storage area spread out.
The draw backs from all the above is it will take longer to warm up and and be driving on wood . ( can’t have your cake and eat it to )
Heat exchanger for the motor exhaust. The draw back from this is more work and space for the heat X.
I’ve been waiting for things to carbon up and self-correct - and it has, to some degree - but not as much as I would like.
I guesstimate my little 4" restriction weighs about two pounds. I could maybe try use something even heavier.
Also, the air-intake layout Is prepared for an exhaust heatex. I will build one as soon as I find the time.
The thing is, I’ve never experienced hesitation like this with any of my shallow-charbed gasifiers. Maybe only because those small charbeds can swing between cool and hot much faster.
Do you think my relativly small nozzles have anything to do with hesitation?
(My thinking is the air velocity at a sudden acceleration may cause enough intensity/turbulence in the top half of the firetube to consume most of the oxygene at that level and delay heatup of the lower part)
My choke is a big heavy dual wall rotor and the choke plate is 1/4 steel
I think I checked off every one of those items. I could add more rails down the sides but I ran out of that size pipe
With 2 pusher blowers and 2 vacuum blowers it takes a solid 15 minutes for my system to come up to temperature and the gas is weak for the first mile or so, lots of stumbling and holding the mix valve rich and it starts to clear up and then I can set a mixture and really start to drive
Do you think these may be the reasons I don’t have any noticable hesitation off idle or after a red light? I thought all that thermal mass may have been a draw back due to longer warmup times and added weight for the little pickup truck. Need to get it on a scale and see how much it weighs now I’m curious.
With my dakota it takes 14 miles of normal flat land driving for the temps to come up to what I consider normal operating range. This normal temp is running flat roads at 60 mph.
At cold start up with blowers on while lighting and then driving off hybirding and then to 100% wood gas with the vacuum blowers still pulling I can switch to full wood 100 yards down my driveway and just about full power at the end of the driveway ( one mile )
I’ve been saving this bad boy for when I get an older truck with a mid sized engine. 4.5 inch ID and has to weigh at least 10lbs. Convenient shelf for me to index on a plate. Might be overkill actually.
On my car it makes a huge difference if I have 2 “x2” x2 “or if I have 1” x1.5 “x2” on how the acceleration is, goes much better on smaller pieces. With 2 "I have a certain tendency to hang wood, if I drive slowly.
If I run the fan for about 3-5 minutes, it takes about 200-300 yards, before I can remove the gasoline (hybrid), full heat in the system after about 1 mile.
Jan, that’s pretty much what I’m used to. With the smaller gasifiers I could even do without the hybriding most of the time.
One big difference with the Volvo gasifier is the heatex temp doesn’t level off until 8-10 miles into the trip.
Fuel size made a huge difference with my smaller gasifiers. This one - not so much. Most of the time there’s more power than I need, except for those 5-10s hesitations.
Strange, but I also have a strange thing on mine, it seems to accelerate better when it is cold, than after a while of driving, do not understand why.
I do not know if this is true, but co can apparently be regenerated to co2 if the heat in the coal is too small, that could be an explanation for the hersistation (but Kristijan may know that).
JO, are your hesitations when driving in town slow speed driving, or after higher highway or road speeds and then coming to a stop then taking off. Like a stop light or sign waiting for traffic. Or is it a combination of them all of them? Does it do it with a full hopper or low fuel in the hopper?
I think you said you do not have a fuel lean/rich gage on the Volvo. But if you do check to see if it happens when you are running lean or rich at the time of hesitations.
Bob
This was usually the case with the Rabbit. I sometimes blamed unsufficient cooling area - moist gas, sometimes bridging, sometimes pulling through a coarse charbed and sometimes a combination of them all. I never found out for sure
