My idea is that the hho is improving the burning characteristics of petrol
which is where the claims about improved fuel economy are coming from.
Would petrol blended with a small amount of hho at the intake manifold of the engine assist the petrol to burn more effiently?

 

You're simply adding an additional fuel and oxidizer source. It may actually create problems, as the combustion temp may go up, leading to excess formation of NOx compounds. The ECU may richen the mixture to bring down combustion temp.

Engine efficiency is affected by more factors than the quality of the fuel stream.

 

Pretty much every car on the road has sensor, and a computer. If you do find something pre-70s, that's still drivable, you might be able to tweak it up to modern levels of efficiency, since that wasn't a huge concern back then, but good luck passing an emissions test. Most cars will run at their best efficiency, with the fuel they were designed to use. You can mess around with the engine, without adding HHO (or anything else), and get some improvement. A basic oil change and tune-up will give miraculous improvements to a neglected and abused car. Changing your driving habits can also make a considerable difference, specifically, quit leave pieces of tire on the pavement everytime you hit the gas...
Mostly, the people selling HHO tech stuff, are the only ones saving money, your money.

 

Simply keeping the thing washed will affect mileage. Ditto for keeping tire pressure correct. The HHO fad has yet to produce any valid numbers, despite large monetary rewards offered for them. All hype, no science.

 

jaque,

I know that water was sometimes added to fuel in some military airplane engines to COOL down the combustion in order to run supercharged engines at a higher throttle setting without burning out the cylinders. And it was only done for takeoffs when extra power was helpful. Being able to run the engine at a higher fuel consumption to attain higher power is not the same as boosting power with the same or less fuel. Remember, water is an ash, not a fuel.

Ratch

 

Here is an article that came up on an unrelated search yesterday. I am posting part of the abstract to whet your appetite. The publisher wants $31.50 for the whole article. My library doesn't carry the journal...I may try Ohio link and some others, when I have more time. This is not a solicitation for someone to publish it here in violation of copyright.

Performance of a spark ignition engine fuelled with reformate gas produced on-board vehicle

Enzo Gallonia and Mariagiovanna Minutillo, Department of Industrial Engineering, University of Cassino Via G. Di Biasio, 43, 03043 Cassino, FR, Italy

Abstract
In recent years, the interest in the use of hydrogen, as an alternative fuel for spark-ignition engines, has grown according to energy crises and pollution problems. By comparing the properties of hydrogen and gasoline, it is possible to underline the possibilities, for hydrogen–gasoline fuelled engines, of operating with very lean mixtures, thus obtaining interesting fuel economy and emission reductions.

John

 

Here are a couple more abstracts of work by the same Italian gentlemen:

http://www.sciencedirect.com/scienc...serid=10&md5=5019a86a9f40325c1fc2c9a21e65e4ba

http://www.sciencedirect.com/scienc...serid=10&md5=76f2c0b20a31eef11e858d7c13587e66

They seem to be dealing with software modeling of fuel mixes and alternative means of generating hydrogen. I don't think they are part of the back-yard boom. It would indeed be interesting to read their work.

 

I Know of water being injected in combustion chamber of gas turbines. They increase the output but reduce the efficiency.

 

Any number of aircraft have used water injection to hold down compustion chamber temps - JU-88's along with NO2 injection, F-105's at takeoff, C-124's for low altitude power flying Ranch Hand missions.

The water does flash to steam and expand, but mostly it's along for the ride. I think I have seen mention of a six stroke engine - yep, here's a link http://www.autoweek.com/apps/pbcs.dll/article?AID=/20060227/FREE/302270007/1023/THISWEEKSISSUE - that injects water for an additional power stroke. Wonder how he keeps the steam leaking past the rings from turning the oil in the crankcase into yellow sludge?

 

An engine burning gasoline produces about half as much H2O as CO2 (isooctane is C8H10). So, water vapor is probably not a big problem, if the oil is kept hot.

I saw that report on the 6-cycle engine. It seems that is something that might actually extract a little more power from the heat of combustion and reduce cooling drag.

John

 

Does make you wonder about stresses on piston crowns, though. Not to mention discussions on better mileage on Perrier vs. plain distilled.

 

Hi
Forget about water injection, it does not work. In Europe/Asia we have fuel economy off to a fine art (gas costing around $10 a gallon). My advice is buy a European/Asian car and get 40 - 50 miles to the gallon instead of a big American with half that MPG.

 

Some years ago,'70's,I saw an article for converting a VW to H2.It used water injection to compisate for the low octane rating of H2. Suposidly it was driven coast to coast.

 

Running a vehicle on pure hydrogen is certainly viable. But you wouldn't be able to generate it on demand; you'd have to carry it in a tank, which would require periodic refilling.

Problem is, there are extremely few hydrogen filling stations around - at least in the States.

 

I think it is still less expensive to burn pure gasoline instead of burning HHO plus pistons.
Going too lean saves fuel but burns the engine instead. Also the increased Nox pollution will not pass an emissions test.

EDIT:
Wikipedia says that a university found that HHO generated in a car increases its petrol fuel economy when the engine is idling. Then the HHO is turned off for enough power for the car to drive.
The ECU needed to be reprogrammed for the extremely lean mixture with HHO at idle. The pistons don't burn because a very low amount of power is produced at idle, just enough to make the HHO.