Warm & Humid Air Modification- feasible or bad idea?

[Waynetc]

As I continue to fit joysticks and buttons into broken Nintendo Wii controllers for projects that start with M, another idea came to mind.

My insights mileage always soars when it's warm and humid. What if instead of the hot air mod that many have done, humidity were added too?

How - Personnal steamer - they are small, can generate a considerable amount of hot humid air quickly for up to about 30 minutes. They run on 120VAC, but a DC to AC inverter could run it. It would be difficult to use when temps are below freezing unless it were fed by warm water outside the engine bay.

Could this be a "nitro bottle" in terms of mpg's? Or should I just use it for my sinuses??

[originalbadbob]

I've had a discussion with a couple of other insighters, and I think there is merit to this. I had though about using a canister with a drip nozzle to drip water onto a plate attached to the catalytic converter shield. After a while, the plate would get hot enough to turn the water into steam. My air intake is fairly close to the cat, and it would suck the humid air into the intake. Whether you get much gain from it or not, is open to speculation. I have noticed my highest mileage is in the summer right after a rain and the road is relatively dry.
robert

[james]

Just a gut reaction, but I think you'd use more energy heating the water electrically than you'd gain back in improved fuel economy.

However, you do have a source of free heat, the tailpipe after the cat. You could maybe wrap some copper tubing around that and use it to boil water. Still, I think you'd have to carry a lot of water to humidify all the air that goes through the engine. If my mental arithmetic didn't drop a decimal point, at 2K RPM, it's sucking about a cubic meter of air every minute.

[atlaw4u]

Here in Texas it has been seasonally cold. However, the last three days have been unusually warm with a few thunderstorms and thus, more humid than usual. I recorded some of my best mpg figures in a long time with 3 straight days of 90+ mpg round trip commutes to and from work and my best door to door ever recorded of 108.1 mpg. The car was running so well and staying in lean burn so long I first thought the gauges were malfunctioning.

Unfortunatley, the cold air returned this morning and dropped my door to door commute into down town Dallas to 81mpg. But then again, it's hard to complain about 80+ mpg.

[IamIan]

You might not have to spend the energy to heat the water...

After all once the ICE gets up to temperature ... further heat is just pumped out of the engine by the coolant system.... If you add very small amounts of watter misted into the air intake ... it will enter the combustion as tiny drops of liquid water.... it will absorb some of the heat released... it will expand in volume...

This way instead of pumping the additional heat away you turn it into more power in the cylinder...

The major issues I see with any water adding system... is the effects it will have on other things... gasoline and oil do not like to be mixed with water... several of the materials used in the ICE and cats and such might corrode when exposed to additional high temperature water.... and of course properly regulating the amount of water.

[Dougie]

I think the improvement in humid weather might be mostly because humid air is less dense than regular air. (Compare the weight of one N2 molecule compared to one H2O molecule...)

[HafNHaf]

dougie has it right. the humidity just makes the air even less dense than the elevated temperature does. until you get to using water injection for detonation suppression, just raising the intake air temperature should do the trick.

[Dgate]

This from Wikipedia....
Water injection is often necessary when adding forced induction to an engine that was not designed for it; the compression ratio of a normally-aspirated engine is too high to cope with more than a very modest boost unless this technique is used.

The system was first used extensively on World War II fighter aircraft to increase power upon takeoff and bring up the service ceiling. A limited number of road vehicles with large-displacement engines from manufacturers such as Chrysler have also included water injection. Saab offered water injection for the Saab 99 Turbo. With the introduction of the intercooler the interest in water injection disappeared, but today, water injection is also of interest because it can potentially decrease nitrogen oxide (NOx) emissions in exhaust. Water injection is primarily used with piston-powered internal combustion engines, but it has also seen use with turbines.

The initial injection of water cools the fuel-air mixture somewhat, which increases its density and hence the amount of mixture that enters the cylinder. But the greater effect comes later during combustion when the water takes in significant amounts of heat energy as it converts from liquid to gas (steam), increasing piston pressure (torque) and reducing the peak temperature with its resultant NOx formation as well as the amount of energy absorbed into the cylinder walls.

DGate

[james]

If I understood it correctly, the Wikipedia water injection is different from what the original post suggested. That was evaporating the water externally to humidify the air, while this injects liquid water (in a fine mist) to absorb energy & create pressure by turning to steam.

I wonder how that would interact with lean burn? Would it increase or decrease the range?

[Dgate]

Surely in either case its water laden air that is producing the extra energy in the combustion chamber.
By using an injector it dispenses with a Heath Robinson device to vapourise the water as it achieves this with combustion heat.
Note this system is normally used with turbos/superchargers for extra acceleration so while a normally aspirated engine may not produce like performance it will decrease fuel consumption which is the main goal here.
Who is going to be first to experiment?
If anyone has experience with Gas/Lpg conversions they normally drill the plastic intake manifold nearest to the head to install gas injectors.
A water system would be much simpler to do as there would be no safety issues or chance of explosions destroying the manifold.
Also it might not have to be timed like a gas system just pressurised and modulated.

DGate