A great Question from Eric Today.
Hi George, I have been trying to find info on how to calculate the fuel consumption for a backup generator that I would like to build, but am not having much luck. Nobody I know has a clue where to look and I have looked online quite a bit. I’m guessing that I am just not looking in the right place. It’s easy to calculate the total volume consumed, but I’m not sure how to figure the liquid fuel converted to vaporized fuel and the air it would displace in the cylinder, and keep the A/F ratio in the correct range. (I am considering propane or gasoline) Any help you can offer would be greatly appreciated. I have always been a hands on DIY person, and the more I learn, the more I realize how much I don’t know. But I enjoy learning new things. Thanks for putting your work online. I enjoy the articles. Sincerely, Eric H.
Eric, the wisdom in what you say! talk to any Gang Greenie, and you’ll soon learn the vast majority have no doubts as to what they know! The Opposite of skeptical really is gullible, and there really are good examples of oxymoron close at hand. today’s example I give, Huffington:Scientific.
Maybe the first question is what kind of generator should we build?
It was not long ago I saw a bone head article in a popular auto magazine about E85 delivering better mileage in an auto than petrol gasoline bought at the pump. The car… a flex fuel vehicle. Obviously the author flunked 8th grade science, as it takes little more to find the flaw in his article.
Fuel consumption numbers are easy WHEN we calculate from end to end. We best NOT make the same mistakes as Gang Greenies and work from one side towards the middle.
The internal combustion engine driving a generator head is a very inexpensive tool for the DIYer, there are some ways to fool yourself, but if you stick with the most basic rules can can do quite well.
No one uses volume when they want their work respected.. even in our hobby groups like here. Use weight to measure fuels.
Postage scales that plug into USB ports are great tools to measure fuel used.
Loads on the generator MUST be pure resistive. (this takes your ability to screw up on calculating real power as you need not compensate for power factor.
You will use respected equipment to calculate power production, and those used power meters you can buy on ebay might be a good choice.
Attempt to keep your work and experiments inside the confines of grams/KWH figures, longer runs are best, starting the measure when the engine is at operating temp. Recording air temp, cooling water temp, exhaust gas temp and more add value to your work.
Of course there’s more.. checking valve lash, engine condition, using the appropriate lube, it can all make a difference, and should be part of your notes.
Once you have a base line, you can attempt to make more power with better intakes and exhaust, better economy, less noise and more.
This can lead to fun. Others, please consider adding your recommendations in comments.. including taking me to task..