Ultrasonic Water Fogger for the intake

[Anonymous]

This is just a passing thought, so I thought I would throw it out there.

On EFI engines with a MAF the engine will produce more power on rainy days due to the fact that the computer is able to dial in more spark advance.

I was looking at an Ultrasonic Water Fogger today and it produced a thick fog with droplets in the 3 to 5 micron range.
: If you were to modify one of these units to the air intake at the front of a car could you expect to get the maximum benifit of super wet air with out any negative effects?

I don't think it would be as useful as water injection on a turbo car. But I think that it would give a measured increase in gas milage on a late model EFI car.

Thoughts?

John

 

[xctasy]

Must be something in the water you drink, John.....something good! :idea:

Sounds like a great idea but how much will the ambient air temp drop?

Looks like the next big thing.

If it is introduced in an atomised state, into an air flow that at a 300 cube engine doing 4000 rpm, could be a 6 by 6 by 6 foot room every minute then it really is super fine, a small drop in a large ocean of airflow. I'd say you'd need to hit the 1 ounce of H20 per minute mark just to get an improvement in power, but it could be done with no adjustments. It's unlikely you'd add enough water to turn the advance up enough for you to see lots of power, but it may have other benifits. You may pump the relative humidity up from 60 to, say 85 or so if you introduce enough. The power calcs then would be helpfull.

How much can the Ultrasonic Water Fogger flow? If you can calc the realtive humidity increase, then you can calc the power increase off some of the Summit Drag Computer charts. :roll: :roll:

 

[Anonymous]

The unit that I was looking at would turn one liter of water into fog every hour.
If the water was heated to 135*F then the amount doubles.
The power required to run it was 850 watts.

I have no idea what it would do with a water/alcohol mix.

Like I said, this is no substitute for water injection. I just THINK that it might make an engine run a bit more efficiently in cruise mode.

I was seeing it as an addition to water injection in a boosted car. Running off the same water reserve, but through a heat exchanger at the radiator.

John

 

[xctasy]

At that rate (which is about ~0.6 ounces a minute), either water or 50/50 alchol/water would make a difference. It may displace air, but it would cool it also.

A tidy idea. At 1.1 hp/0.85 kW, you may be best to use some other means of running the system. It would only be needed in low manifold pressure situations and/or where the piezo-electric knock sensor kicks in. You may be able to pre-pressure or demand drive the system using an auxilary power supply.


On another note, John, I got a great deal of insight out of that NASA article on water injection. It confirmed information I've squirreled away from other sources, and gives me some more inpetus to looking at building a super-high compression 'mileage maker' engine of my own. There is an optimum amount of suppressant that can be used and if the set-up is done right, the part throttle economy of such an engine could be superior to an EFI engine.

 

[Anonymous]

I'm glad you liked the NASA article. But to tell you the truth, it rather out distanced my rudamentary education.

I never did quite grasp just how much water they were adding. Oh well

John

 

[xctasy]

Yeah, they ( http://naca.larc.nasa.gov/reports/1943/naca-report-756/ ) started doing 'triples' with:-

1. the air/fuel ratio backwards as a fuel air ratio(11:1 is 0.091, 12.5:1 is 0.080 and 15:1 is 0.067).

2.Then they said what the BSFC was in pounds per hp per hour. (0.50 to 0.8 or so)

3. Then decided to use both a decimal fraction of water to fuel (0.6 = 60 % of the gasoline supply).

4. Oh a forth spin-ball. The total amount of water and gasoline added as a weight per hp. Ie the by-product water existing the combustion process via the exhast (after cooler) in pounds per hp per hour. The amount of 1.42 was quoted.

The thing is a 1933 fuel inected 202 cube air cooled engine at 2000 rpm would be hard pressed to hit more than 75 hp. It was likely that the total amount of fuel with 75 hp or so would be about 45 pounds of fuel burned at a 0.6 BSFC.

In terms of water by volume, 45 pounds is about 5 gallons, so if you could use 0.8 of the total fuel volume as water (80%, in other words), then you'd be using about 4 US gallons per hour.

Only when you need to stop knock, though, not all the time.

Yippee. But it's rocket science, it's supposed to be hard!


We need some food John. This was hard work.....

 

[goinbroke2]

If it's added as a fogger to increase the humidity, you will lose power. Water displaces the air, or actually the volume of air that can be ingested.
If it's sprayed in in tiny droplet form it will supress knock etc.
Of course I'm basing this on my personal experience of drag racing for the last...well, LONG LONG time.

Humidity kills power faster than ambiant air temp increasing, but less than barometer dropping.

 

[xctasy]

Great point. I thought it was the other way around with water in the air, but I bow to superiorknowledge.

Say, what is the relative power drop from 25 to 75% humidity? I don't have any tables to check up on.

 

[Anonymous]

Good stuff, Xecute!

I have a copy of Sir Harry Ricardo's book The High Speed Internal Combustion Engine, in which he thoroughly examines the dynamics of substituting water for fuel in a gasoline powered engine. As far back as the late 1920's he came to the same general conclusions as NACA did a few years later. And like NACA he was interested in knock delay, but for years I have recognised that this approach could be just as effective in achieving ultra-lean burn engines that demonstrate significantly better fuel economy than the same engine burning pure fuel. Of course, the total liquid consumption would be slightly higher than with the basic engine, but up to 60% of the liquid consumed would be water.

Interesting, eh?

 

[xctasy]

Thrilling stuff. I've looked at detonation control on my 228 when it gets a supercharger. The very act of super charging creates effective compression. My 3.4 liter supercharger at 6000 rpm can produce a theortical 725 cfm if it were 100% efficient, and about 550 cfm if its as efficient as I recon. On an engine with 10:1 compression and a 270 degree cam, this would hit detonation city very fast. The effective compression could be about 16:1.

I decided long ago a cheap positive displacement on a smaller engine with good detonation control, could be fairly economical if it pushed the incipient detonation barrier, without trashing the pistons.


If I could spike the water with methonol and just use propane as a base fuel, then I'd come home fairly economically on the hp per $ unit of fuel basis.

Long ago, the aero industry and pionneers of the piston engine had it all mapped out. I'm gonna take a long drink of this information. Surely the old wine is better.

 

[broncr]

"...the engine will produce more power on rainy days..." John

Long standing words of wisdom that also apply to carb'd engines. Again, excuse the brain cloud, but how exactly did we arrive at the conclusion that mechanical rain won't work?

Rain water is also displacing air, yet the extra power is still there...If these words of wisdom are a wives tale, what am I feeling in the seat of my pants? Please don't tell me it's my wife's tail...

 

[Anonymous]

I know I can feel the difference but I also know that track times and dynos don't lie.
Maybe it's different at low rpms only? I don't know. I'm really at a loss for an explanation.

John

 

[xctasy]

Here's another 'devils in the detail' speal, if you will hear me out. It may be BS because its years since I did a climate paper. There are three terms to consider

1. Barometric pressure (lower pressure,less power, less dense fuel air mixture)
2. Humidity (greater the humidity, less power????)
3. Ambient Temperature (higher the temp, more rarified the oxygen particles, less power)

When one changes, so do the others. Humidity alone may be a snapshot with a poor persepcitive, cause other things change too.


Weird Idea 1:

If it's a hot, dry day of , say, 50% humidity at 100 degrees, then a rain event will drop the ambient temperature fast in a downpore. Could go down to 85 degrees, or so. This will lower temprature, and stop the rise of water in the atmosphere through the formation of steam. Eventually, the humidity MAY rise, but not straight away. The rain cools things, but the humidity can only rise with a heating factor from the sun to create a state of change. In the first 30 minutes of a good rainstorm, the humidity may stay at a constant 50 for some time, (perhaps even drop!), then rise to some other value after the rain event. Then if the rain is clearing, and the sun shines, it could become very humid again. Additionally, the barometric pressure would change with the weather too, and that has a bearing on power. You can end up chassing your but on a mock weather event, but the principals should bear out that what GoinBroke says is actually quite true. It's just clouded by air temperature, barometric, and water temperature changes happening at the same time.

Climatographers, weather men here?

Weird Idea 2:

Anyway, the hypothetical Ford F150 cruising the highway before the rain event 'sees' a bulk temperature of wet and dry particles of 100 degrees. During a rain event, it 'sees' wet particles of atomised water at, say 75 degrees, and then air which is now cooling fast to , say, 90 degrees. Taken together, the air temperature at the air cleaner could be less than 85 degrees from the chill provided by the rain event. The humidity at the air cleaner could be more than this suggested 50%, but it's cooler also. So power goes up even with a humidity rise.

Barry Grant and all the other fuel systems and drag race suppliers provide weather stations that take all these facets together, and allow you to tune for manximum hp. Somewhere, there is time when humidity can rise and power can rise, but only because baromotric pressure has risen and temprature have dropped.

 

[goinbroke2]

You know.......my dad used to tell me about "wet power" on hurcules aircraft he worked on. Water inj worked to cool the intake and numerous other reasons to raise the hp.
But humidity DEFINATELY lowers hp.
hmmm.... strange eh?

I will hazard a guess and say that on a day that's 29.1 barometer/50% humidity/80 degrees, adding water inj to an engine with a relatively hot intake will increase hp.
Change the day to 29.1/80%/100 degrees and I bet the water inj will loose power as the engine is already injesting a lot of water in the first place. (causing a relative loss in power) That and the fact I suppose that at 80% humidity the intake wouldn't be as hot nor be as succeptible to cooling by way of more water.

Another thought, perhaps as a storm comes in the barometer rises and the increase in power is because of that, and in spite of the high humidity? But I forget which way it goes when a storm comes in..high pressure moves in or low ?

 

[broncr]

? But I forget which way it goes when a storm comes in..high pressure moves in or low ?

That would be LOW pressure. Taking this all in again (as the brain cloud lifts) it is a complicated intermix of ambient air temp, pressure and humidity. Lower pressure = less air molecules per cubic foot, colder temp = more molecules, & increased humidity = less.

The Meteorology classes rise from the mist of memory - I think you're on the right track Execute - though humidity may have risen to rob some horsepower, the loss is offset and exceeded with a cooler, denser air charge.

Accepted that dyno's and track times don't lie, I still believe in my SOTP meter...maybe what we're experiencing are microbursts...

 

[FastRonald]

8) Use windshield washer fluid. Water and alcohol mixture works out fine for us.

 

[FastRonald]

8) We are alos using vaccuum as the means to introduce the "water" into the engine.