I recently was playing with my charcoal gasifier and Predator 8750 inverter generator and wanted to perform an experiment to see how much charcoal is consumed when running the generator in regular mode versus ESC mode (or ECO mode as I call it).
Basically when ESC mode is turned on, the engine will run at a lower RPM when there is no load on the generator. When a load is detected on the generator, the engine will increase RPM to accommodate the increase in load. Once the load is gone, the engine will return to the lower RPM. This is different than regular mode in which the generator runs at a consistently higher RPM all the time (more like a regular non-inverter generator). ESC mode is supposed to save gasoline.
In my tests with the charcoal gasifier, I have noticed that when the generator is running on ESC mode and no load, the gasifier runs much cooler than on regular non-ESC mode. So, I wanted to see if there was a significant or even noticeable difference between the two modes with how much charcoal is consumed with no load on the generator.
My test was to basically fill the gasifier hopper, flare the gasifier until good stable gas was achieved, run the generator on regular mode for 20 minutes, shut down the generator, open the hopper and measure the drop in charcoal with a tape measure. Then, I allowed the gasifier to cool down completely and repeated the process except I ran the generator on ESC mode for 20 minutes.
What I found was that, even though the RPM is definitely lower on ESC mode and the gasifier is running noticeable cooler, the amount of charcoal consumed appears to be almost identical between the two running modes.
Now, I have only done this test once and so my sample size is very small, but I thought it was an interesting result. Based on how cool the gasifier ran and the lower RPM, I thought I would see a more noticeable difference in charcoal consumption. Of course, measuring the drop in charcoal with a tape measure isn’t exactly accurate. I also don’t really know the difference in RPM between the two modes so I can’t calculate how much less air is actually being drawn though the gasifier.
A major caveat to my testing thus far is that I have been using my “Big Bag O’ Charcoal” as the source of charcoal for all of my running of the gasifier. The “Big Bag O’ Charcoal” is filled with the charcoal that I have recovered from my fire pit after we have campfires in the back yard. The wood used in the fire pit is mainly maple, but there could be a pine board here or there that gets thrown into the fire pit on occasion. So, regarding the test, I cannot confirm that the mixture of hardwood to softwood ratio is equal on both runs. There could be more hardwood or softwood on one of the runs that is throwing off the results. I plan on making a bunch more charcoal from maple and trying the experiment again to see if that consistency yields different results.
Does anybody have any thoughts on this? Am I incorrect to assume that the consumption of charcoal should be different based on the 420cc engine running at two different RPMs? Perhaps the difference just isn’t enough to measure with my crude measuring technique.