I haven’t dug down through the charcoal yet to find out. I’m curious, too. After a few more drives, I’ll check it out. It seems I may be getting better gas now. I’m trying to master temperature control with EGR and water drip. I was concerned about having trouble lighting and monitoring the temperature since the charcoal is not clearly visible, but that hasn’t really been a problem. I can see well enough. Since the nozzle is about 4 inches from the bottom of the barrel and the reaction zone is above it, I don’t have the depth of charcoal fuel which I had before. I think it will be OK, especially when I start to burn hardwood charcoal. I have yet to do a test to see how many miles I can get from a reactor full of charcoal before overheating. The upper part of the barrel does seem to be getting warmer quicker than it did with the lower reaction zone. I think I’m getting potent gas more quickly than before. It also seems that I’m getting more resistance in the gas flow, probably because of the smaller area of nozzle opening. I’m closing the air mixture valve a bit more now.
According to Eddy’s compilation of information on your gasifier, the wall of your nozzle is 10mm thick. Mine is 3/16 inch which, if I’m thinking right, is about the same. I bought a 12 inch long 1.5 inch ID steam pipe nipple to use for the nozzle which is thicker than the standard 1.5 black iron pipe which is about 1/8 inch thick. I’ll keep you posted on the progress.
I had an interesting time Sunday evening. My church had a back-to-school hot dog dinner followed by home made ice cream event. I was the after-dinner entertainment. I demonstrated the charcoal car and gave rides for a half hour or so. I was so afraid that it was going to embarrass me like it did the last time I tried to show off for a crowd (“Pride goeth before a fall”), but everything went well this time. It handled me and two passenger quite well. I’m practicing for a possible exhibit at an antique tractor and engine show in a neighboring town in October. More later.