The colors on the graphs aren't all that easy for me to differentiate, so it takes some concentration to make sense of what is going on. I can "fatten up" the lines and the legend dashes, but there's a limit to how much of that I can do without creating other problems. I only use this complex view to get a bird's eye view of the action. When I attempt to home in on an issue, I make simpler graphs that plot only one, two or three variables.
For example: By plotting only the "engine" (lite blue, at the woodgas carburetor tee) against PR6,(orange) which is the output of the cyclone separator,
I learned that the two pressures (suctions) are exactly 180 out of phase all the time!
This is hard to believe, since they take readings on both ends of a pipe that is only about 6 feet long.
I am pretty sure this means I have some sort of a pressure wave going.
In normal operation of the JXQ-10, that is, supplying the two burner stove, there are pressure pulses at about a one pulse per 2 second interval. These pulses bounce the water up and down in the center and right hand chambers. As the suction in the center chamber increases, the height of the water column in that chamber increases changing the natural pulse frequency to some degree. This would occur at some constant rate once it stabilized. When the user turns one burner up or down or turns on or off the second burner, everything changes. If both burners are turned off. The blower sucks hard enough on the center chamber and blows hard enough on the right chamber to push the gas from the right chamber (the output chamber) back into the center chamber. The net effect of this action is to reduce the suction on the grate to zero, so no more gas is produced. That system IS the regulator. Once I add an engine that SUCKs on the output, instead of the output always being at a positive pressure, everything changes.
I could go on and on with guesses and (possibly) flawed observations----.
However, what we DO know is that we are getting 30 Hz pulses of suction from the two cylinder engine as it runs at 1800 rpms.
The magnitude of these pulses varies with engine load. The magnitude also varies with gas quality as the engine governor tries to suck in more fuel if gas quality starts to drop. All these things are going to effect the complexity of what those pulses do to the rest of the system.
The one-half Hz positive-going filter pulses beat against the 30 Hz negative-going pulses from the engine. And predicting the resulting harmonics is darn hard since magnitude conditions and even net volume of the chambers changes all the time. You can see that my 5 second per sample rate is 'way too slow to catch the wave envelope of the primary pulses, let alone the harmonics. I'd probably have to sample at about 300Hz to start to see all that happen. Whether I will do that or not, is yet decided. As I think I have said earlier, the stock filtering system is NOT designed to handle an engine. But, since I do use it to cool and filter the gas, I must be sure that I run it in a mode that NEVER uncovers the hot gas inlet to the center chamber.
I already mentioned one of the main "learnings" from this test, but I still have to solve for keeping the temperatures up as long as I want to and to keep the right chamber from ever going positive while the engine is running. Next test will be to run about the same way, but with the differential pressure sensor installed across the fiberglass filter box.
But!!!: If you watch the Yahoo woodgas group, you have no doubt heard of "drizzling" wood chips into the hopper to keep the depth of burning under control.
That will be central to changes to our next runs in the spring of 2014.