Steve , I am trying to advance slowly and so far finding out what does and does not work well for me , i see others that are having great results with downdraft , so i will persevere till i am close enough to my goal to say there done it ! Next
My other attempts of downdraft where a few years ago and i never got a strong cool gas , its only when i saw Matts unit running that is more like my situation here and that’s my ideal setup and it got the old brain juice’s flowing again .
Dave
Dave, with my big unit and it’s 1" ID nozzle pointing down at a 45 degree I have about a 12" distance to the grate. My gas came out almost too hot to touch but it was cool by the time it got to the filter, but that was 21 feet of 2" pipe for cooling.
I need to figure out a way to seal off a restriction with my situation, maybe a bit of ceramic wool. Since I only have one nozzle I don’t think I could depend on an ash cone either so I may have to make a cone. For the 4 liter range I was thinking 12" restriction.
I know it wasn’t cracking a lot of water, or my charcoal had more moisture than I thought. Clear water in the filter box and in the PVC routing after the filter.
The hottest place on the gasifier was on the barrel wall right below the nozzle. Not enough of a nozzle length to have charcoal for self insulation I think.
I may try to make a Double Flute like Kristijan did and I’m glad my air in is a coupler so I can tinker with the body. It’s making strong enough gas to run the truck but I don’t like how moist the gas is for my filter, I’m afraid of it clogging.
Yeah the hose temp is how I rate the machines. If I can not physically grab my exhaust hose and hold it in my hand then that is too hot and the gasifier is being over driven. Your pulling to much volume than what the char bed is capable of processing.
Although the gas exit must go through the Fusion first. So that is cooling the gas down some. But when I run the DFX-S1 that has direct out gas exit that unit also runs cool enough I can grab and hold the exhaust tube when running the 212 cc engines. When running the 420 cc engines yeah it gets hot and you dont want to be holding that hose. I had to change the plastic cam lock couples over to aluminum because they were melting on the DFX-S1 running the larger generators. But I dont rate that unit to run any larger than the 212cc @ 1800 rpms. So had to add that aluminum couple as a safe guard.
But all others have an aluminum end at the gasifier side and a plastic couple at the filter side. If that plastic couple is melting, something is wrong or the user is over driving the gasifier.
Oh I think I’m definitely over pulling it. I’m wondering if a ring of jets at the same 12" height will run it cooler. The Mako sized for 2-4 liter engines used a 12"x12" active zone beneath the 4 nozzles.
It could be a velocity thing. Maybe my nozzle is a tad too small for the 4.3 and if I upsized a bit, or distributed the flow over multiple jets it would run cooler.
I’ve thought about making a fan shaped nozzles like some cross drafts have used. Use some 1/4" plate or thicker if I can find it. I’d ideally want to match the area of at least a 1.5" pipe in my case.
The DFX-S4 is set up with a 1 - 1/4 inch coupling adaptor. So I can fit the standard nozzle used the S-2 and 3 units or I can bump it up to a 1 inch nozzle. It is designed to run up to a 2 litre engine. To run larger engines simply add on a module. You would want the second module anyways so you have plenty of fuel per hopper load. Im hoping a twin set up will run most V8’s 5 to 6 liters. That will more than likely push them to their limits.
I think with your narrow body for the gasifier it definitely aids in water cracking that might be in the fuel. I guess I’m just trying to figure out a Barrel form factor fix.
Actually I can go to 1 1/4 with a different nozzle arrangement. But the S-4 has a massive active zone much bigger than 12 x 12. Its 14X18 deep and 12 inches in depth.
Yeah mine is 12 inches deep and about 22 inches in diameter. I never measured the direct distance between the nozzle and the gas exit but I think it’s about a 24 inch distance.
So to create this X shape you have two triangle shaped hollow chambers on each side. On the top side Id angle them so that fuel on the top will slide toward the nozzle side.
If you are looking straight down at the bottom you will see an X. You will have two pyramid shaped hollow chambers on two sides and then the two empty areas. One empty chamber is your oxidation zone on the nozzle side and the reaction zone on the other. The two hollow chambers are just dead space to direct your flows to a focal between sides. Basically flip an imbert on its side.
I will experiment with this myself. I am now putting together our business plan and development direction for the future. The DFX is already getting redesigned and now that this idea just came to be Im going to add that. I wont be changing anything any time soon though. The next DFX model will not come out until 2026. The VersiFire and controls systems all will be redesigned for then too. The current version one of the VersiFire isnt even done yet. So none of this will start until then. The plan for the 2026 DFX is they will come with controls standard and they will be way more refined than they are now.