Water injection improves MPG?

[teoman]

It should be more efficient if you inject the lpg with a gasoline injector.

After the intercooler could be a good spot because the heat would have been expelled by the intercooler and the phase change of the lpg will have the most cooling effect.


PS it was me fiddling with steam injection but i sold the car before the implementation. I have a lot of data on my thread. The grand idea was use steam as a warm air intake by controlling the amount with an injector. One would obtain maximum atomization (minimum water droplet size ) in the process. And the setup is relatively simple.

[Galane]

A thing I recall from many magazine ads in the 80's was an ultrasonic atomizer to put under a carb. It appeared to use some type of piezo transducers suspended from a plate via four stiff wires. One per venturi.
I assume there would have been engine specific versions to place the transducers as close as possible to the bottom of the intake chambers beneath the carb.

The concept was to very finely vaporize any liquid gasoline that landed on the transducers and perhaps blast some to a fine mist in mid-air.

I never saw any tests by actual buyers of them.

Ultrasonic vaporization of liquids is a real thing.

https://www.youtube.com/watch?v=N_AIZBCkXnk

It would be interesting to see what would happen with introducing ultrasonic downstream from a throttle body injector.

[cRiPpLe_rOoStEr]

Originally Posted by teoman

It should be more efficient if you inject the lpg with a gasoline injector.

I'm aware that some cars fitted with direct injection are retaining their stock injectors when converted to LPG.

The grand idea was use steam as a warm air intake by controlling the amount with an injector.

WAI is not so desirable in a Diesel. Steam enhancement would work better as a replacement to the EGR charge.

[teoman]

Yep, you are %100 correct.

My car was NA gasoline fueled, converted to LPG. Lpg had its own injectors and was injected in gas form.

But the I think his intent is to have the lpg supplement the diesel a little bit. A bit like NOS in which case the cooling effect would be desirable in my opinion.

As rooster mentioned wlsewhere injecting LPG in liquid phase can be a bit tricky when used as primary fuel. It can freeze some components linke valves etc.

[ar5boosted]

Originally Posted by Galane

It would be interesting to see what would happen with introducing ultrasonic downstream from a throttle body injector.

My 2c worth is that internal-combustion-engines can easily digest much more water than is in that type of mist.

So mist like that, whilst looking nice, is pretty useless.

The next issue is that the life on many Chinese made Misting kits isn't very long. You're better off just spending the $30 on fuel rather than on wasting $30 on electronics to save $3 worth of fuel.

Just being honest.

Having said this, I have used fuel on those atomisers and that does work.

[teoman]

For a diesel, in my very ignorant opinion, having water in liquid form in the combustion chamber just cancels out the heat energy of the fuel. I had calculated exactly how many ml of fuel a liter of water will cancel in another thread.

Water in gas form displaces air (and its oxygen) so under high fueling it is reducing the capacity to burn fuel. It is beneficial if you are getting really high egts. But from an ecomodding perspective it is not much use in a diesel.

So when can it be beneficial for an ecomodder? If you cool the intake charge on a diesel efficiency goes up. So again in my very ignorant opinion, as ecomodders we do not run very high afr's. So the benefit comes from cooling i.e. the evaporative cooling of the water.

So if you filled your intercooler up to half with water the air passing through would cool down by extracting the vapor from the water. But this may not be preferred as you would be unnecessarily heating up the water. But if you measure air humidity, air pressure and mass then you can calculate the amount of water needed to bring it to %100 humidity. And that is the amount that will provide cooling. Any more and you have liquid water floating about.

The injection is beneficial (vs just having water stand around in the intercooler) as small droplets have a lot more surface area and are easier to evaporate.


PS: filling the intercooler is a stupid idea, it was just an example.

[teoman]

Also in my opinion people misunderstand the energy transfer. Water vapor exiting the engine, anlthough cooler has a LOT more energy in it.

[ctmaybury@yahoo.com]

Water injection on a turbo diesel can be used for economy. Cooling the intake charge is important. Fooling the computer is very important. My plan is to super cool the intake charge. Wihout some kind of iat sensor bypass, the computer will retard the injection timing way out of the economy range. You can bypass the iat sensor with a fixed value resistor, and the computer thinks it's a nice warm sunny day. That's why I set up my 99 with an older style injection pump. No computer influence on anything.

I would love to inject the liquid propane directly into the airstream post compressor, but it would be too hard to meter. Anything more than about 25% propane and you blow up your engine.

[teoman]

Injecting propane after the intercooler is better.

The hotter the intercooler (delta temperature) the more thermal energy it will reject. And you will have a cooler charge.

Propane will instantly turn gasseous so it will not be a problem.

As long as your setup has enough distance or continuous injection for full mixing.

[ctmaybury@yahoo.com]

Agee with you. By far the best use for cooling the intake charge with lpg is liquid in the intake. Am I goimg to risk blowing up a 10k dollar motor by alowing too much propane to go through it. No way.