Ok -- I'll byte. I'm one of those "arm chair physicists" that predict it can't increase MPG for various reasons.
However, I believe experimentation like this can be a good learning experience, both
technically and in
psychology, even if the device completely fails to increase mileage.
As they say, been there, done that, with a collection of T-shirts. Back in the late '70s I belonged to a club call the "100 MPG club" in California. We'd been through two fuel "crisis" where everyone waited in long lines to buy fuel at high prices. We could only buy fuel every other day based on whether the last digit of your license plate and the date was odd or even (no vanity plates back then). There were seminars at the local college, people with degrees in science and engineering, people that claimed to have seen it, done it, and said it was suppressed by the oil companies, etc. The key element to the "theory" (actually a hypothesis) was better atomization of fuel into a pure gaseous form, as well as a lean mixture will double, triple, or more the MPG. When confronted by the physics of only so many BTU's being available, the answer was that there was something unknown happening -- sort of more energy available then a calorimeter could measure. That's the only explanation since people right there would "testify" that they had seen these great results in there experiments, but there are also a lot of technical details to get it work 100% reliably, and of course more work to get it commercial, then potentially make a ton of money. And if you do get it to work, you could get bought-off (or knocked-off) by big oil.
I'll interrupt the story for a moment to note the similarities to the HHO movement. People "testify" about the successes they've had, it defies the laws of physics, and the explanation is that something unknown is creating more energy then routine physics can explain.
Meanwhile, after buying a lathe and a milling machine, plus access to even more tools, I built the ultimate true vapor carb. It evaporated fuel in a stainless steel boiler located in a custom exhaust manifold, then went to a custom high temp pressure regulator, then to a custom vapor carb that was actually a variable area flowmeter with an air/fuel ratio adjustable from inside the passenger compartment. A regular carb sat under the new carb, using a two way solenoid valve to shift fuel between carbs -- start on the old one, then switch to the new one after exhaust heat starts. I had to leave the hood off, it looked like some type of super charger. Leaving the hood off also provided safety ventilation in case it leaked and ignited -- forgot to mention this was a 1973 Pinto.
I had to use water injection to control the detonation at high load. It had noticeably crisper throttle response, and I even ran it through one of the smog check stations for an emissions print out. However, preliminary MPG was looking only slightly better then stock, which I finally confirmed on a long freeway round trip. The roughly 10% improvement I saw was the same as fuel injection would give at a much lower cost, etc. About three years of all my spare time wasted, except for all that I learned.
I just wanted to prove I could build it, and also prove whether the "theory" was true or false. The technical stuff learned from this is self evident. But more interesting is that some people just make $hit up to get attention. Others live in self delusion with a shot of incompetence -- they fill up the tank to the top for a test, then yank the nozzle out at the first click on refill, and they only drove a few miles downhill for a test. Some are educated with degrees, some are self taught. Some are true believers, and some are in it for a buck. Some of us are interested in the facts, the truth, and real science, whatever the outcome.
Best of luck. The education can be worth the effort regardless of the outcome.
