Jan, it’s only me again
Most people don’t care too much about filtering. Complexity reasons mostly, I think.
After 40,000 km of DOW it’s my experience that soot only causes a problem in the narrow and turbulent throttle body position. With the dry intake of a mpfi (no gasoline spray) not even the intake runners seem to collect more than a very thin layer.
Since my throttle plate axle seems to dislike the heat of burning the soot (it jams) and the tb is easy to remove, I’ve cleaned it manually lately. 10-15 min, 2-3 times a year or whenever the idle gets too high.
If you still want to add some complexity to the system I would vote for Max’s suggestion to reheat the gas slightly and use a paper filter (regular air-breather filter).
Edit: I would prefer straw before fine grass, which will probably pack and clog more easily.
Soot will not ruin a engine. Tar will. But tar is allmost impossible to filter out anyway so dont worry.
Its important to get the ash out as it is abrasive to the dngine. Cyclone will do most of that, then the hayfilter. The straw inside is wet and it will stick to ash like a magnet. Soot however is water “soluble” and it can ride with microscopic droplets to the engine, where it dryes out in the manifold thats why throtlebodys soot up. But agen, its harmless apart from looking bad
Ok, no more cooling after point 3 is needed?
Plain paper filter, do you mean I can use the filter that is standard for my engine, though twice the size?
All this happens in the back part of the vehicle, so one has to take into consideration the risk of new condensation during the transport to the motorcompartment!
It would be a “selfdestructive” measure to “assist” that to happen with unfiltered gas!
So the answer is a clear NO!
Keep your standard air filter in the motorcompartment for what it is intended to do there!
The paperfilter for woodgas is set just after the reheating mantel welded on the cyclone.
The reheating is intended for keeping the gas pretty warm to avoid the destructive wetting, that easily happens “preferably” at start-up! Under normal driving circumstanses too!
This paper filter is preferably a cylindrical type, as it is easier to clean and keeping air–gas tight!
No leakage allowed.
At start-up gas should be let out BEFORE the paper filter!
Preferably even before the cyclone! (If not afraid of sparks)
Several “practical” builders have neglected this, and destroyed their paper filters by wetting them!
No use to be “smart”!
Most motor part stores have (hundreds) of different filters for different motor sizes and uses…
In this case an “independent” METAL-model, tubelike and easy to open in the end(s) , easy to change the filter element and reliable gables = having reliable packings that handles frequent openings and closings!
Input & output studs for easy (metal)hose attatchment…
No flimsy rubber-stripes!
Enough room for ash. Soot passes wet condensing coolers.
2X the normal need for your motor size gives an easy mind and comfortable cleaning intervalls…
Your fuel size seems good to start with, but soon you will find out in which direction to go. The charbed is the teacher…
LOOK OUT: Normal airfilters have only the output side of the filter made reliable; they do not pay any attention to the input side, while they take the ambient air “from anywhere”!
Thank you Max, for a great over viewing with words, that all of us can easily understand. I did not realize that with this type of setup you still use the engine filter, for a back up fail safe.
I also now see that you have to get the temperature up in the Gasifier first by passing the gas from going through the reheating mantle filter keeping it clean while it is still to cold to do the proper heating of the gases and filtering. Okay now this is done by flaring before the mantle prehearter filter. Bring the temperature up first then let the gas go through the filter and then up to the engine filter and into the engine with now very clean gases.
With the gases cooling as they move to the engine compartment, some condensation might happen especially in colder winter months. This is where the moisture traps like Wayne has come up with would help. Thanks again for your input.
Bob
Hi Max, when I read what people write, I picture it in my mind of what they are saying. Sometimes I picture it wrong, like what was said. I picture in my mind wood gas coming into a set up like Wayne has on his Dakota trucks with the gas coming into the air cleaner with a paper filter in place. With the gas being preheated from the mantle filter on the gasifier. I see now the mantle filter is the last filter for the wood gas. With the air being always filtered separately.
Sometime I think there is something new being said, you were just confirming what has already been done in the past that has always worked with gasification.
Bob
Isn’t it pretty good with big buckets? (if you have space)
When JO was down here with me he started his car on the gas that was in the system, should there be some more gas left with big buckets?
Hi, Jan!
21.2.2020
Buckets for buckets sake is not filling any purpose; there will be a need for space anyway by the time!
Have you investigated the availability of “useful buckets” lately?
You have to solve the filtering of two flows!
On scrapyards you can find airfilters for trucks and buses, pickups for a few Euros. See to it, that filters are still awailable for that model!
Otherwise you sit with a useless bucket, if it cannot be used for something else…
Jan, I see one more advantage with volume.
If you stop at a redlight idling you’re making very rich gas (low on nitrogen). Then away you go, consuming that gas while accelerating.
With a somewhat cooled down charbed, it can’t properly take care of all the sudden steam and CO2 produced right away. The gas will be weak for a little while, but it doesn’t matter much if you’re already up to speed.
Max is right though. Space is often limited with vehicle gasification.
Hi, Jan-Ola!
21.2.2020
Sorry jumping in (between) in the discussion!
Your observation is a very general one; most builders experienses this phenomenon.
In my old “cold-air” Imbert with space-ceramic hearth-bottom and flat reduction zone, no observable gas weakening is noticed within ~5–10 minutes. It takes off from traffic lights in an optimal fashion.
I think the “full diameter” reduction zone is to “blame” for preserving the heat sideways more than traditional narrower reduction zones.
The “cold-air” intake is always rather cold, so it is less affected by heat blasting or not, at the hearth-sides. No air heating mantel.
