I remember hearing about water injection being a bad thing for an engine. I think it had to do with city water chemicals and not distilled water but I'm just making sure. I'd like to try out a water injection setup for a n/a engine and I have well water, any reasons not to bother?

 

Water is fine.
Denatured alky is even better.

The impurities in water are in the order of PPM. Nothing that would bother an engine chemically.

Be sure to goggle for NACA, In cylinder cooling, and if you can find a copy of Sir Harry Ricardo's High Speed Internal Combustion Engine, that would help. Also, Robert Harris posted a *paper* about what water does in the combustion cycle, over at DIY-EFI.

 

Some city water has a lot of chlorine in it. Not something I'd want to put through an engine. The well water may be OK dependent upon the amount of minerals in it. They tend to clog the nozzles which becomes a pain. Distilled water can be had cheap via the basement dehumidifier. Also good for the radiator.

RBob.

 

Another good place is acme. Last time I went to the local one to get water to fill the rad they had lots of cheap distilled water. As fro dehumidifiers/ A/C runoff catchers, the ones in my house look like fungus zoos. Probably stuff in tehre that could kill if it became airborn. Although rolling out a cheap one and leaving it outside in teh summer is a good way to get clean water, albiet electricity isnt exactly cheap around where I am.

 

Chlorine evaporates fairly quickly, leaving a bucket of tap water in an open space overnight will get rid of most of the chlorine in there.

 

Check this forum out:

http://www.aquamist.co.uk/phpBB2/index.php

 

From: Robert Harris <bob@bobthecomputerguy.com>
To: DIY_EFI@lists.diy-efi.org
Subject: Water and its effect on combustion.
Date: Mon, 10 Jul 2000 10:24:08 -0700
Message-ID: <9ptjms0uu4oe292mpk6a6vhm2hn8bu9h1j@4ax.com>

Let us take a quick look at ignition. Those who have a Heywood can look it up
- mines on loan so going by memory. The first thing that happens is a plasma
cloud is formed by the arc consisting of super heated electron stripped atoms.
When this cloud "explodes" a ball of high energy particles is shot outward.

The highest energy particles are the hydrogen atoms - and they penetrate the
charge about 5 times as far as the rest of the particles. As they lose energy
and return to normal temps - about 5000 k - they begin to react chemically
with any surrounding fuel and oxygen particles. The effectiveness of spark
ignition is directly related to the availability of free hydrogen. Molecules
containing tightly bound hydrogen such as methanol, nitromethane, and methane
are far more difficult to ignite than those with less bonds.

During combustion - water - H2O ( present and formed ) is extremely active in
the oxidation of the hydrocarbon. The predominate reaction is the following:

OH + H ==> H2O
H2O + O ==> H2O2
H2O2 ==> OH + OH
Loop to top and repeat.

The OH radical is the most effective at stripping hydrogen from the HC
molecule in most ranges of combustion temperature.

Another predominate process is the HOO radical. It is more active at lower
temperatures and is competitive with the H2O2 at higher temps.

OO + H ==> HOO
HOO + H ==> H2O2
H2O2 ==> OH + OH

This mechanism is very active at both stripping hydrogen from the HC and for
getting O2 into usable combustion reactions.

Next consider the combustion of CO. Virtually no C ==> CO2. Its a two step
process. C+O ==> CO. CO virtually drops out of early mid combustion as the O
H reactions are significantly faster and effectively compete for the available
oxygen.

Then consider that pure CO and pure O2 burns very slowly if at all. Virtually
the only mechanism to complete the oxidization ( Glassman - Combustion Third
Edition ) of CO ==> CO2 is the "water method".

CO + OH ==> CO2 + H
H + OH ==> H20
H2O + O ==> H2O2
H2O2 ==> OH + OH
goto to top and repeat.

This simple reaction accounts for 99% + of the conversion of CO to CO2. It is
important in that fully two thirds of the energy of carbon combustion is
released in the CO ==> CO2 process and that this process occurs slow and late
in the combustion of the fuel. Excess water can and does speed this
conversion - by actively entering into the conversion process thru the above
mechanism.

The peak flame temperature is determined by three factors alone - the energy
present and released, the total atomic mass, and the atomic ratio - commonly
called CHON for Carbon, Hydrogen, Oxygen, and Nitrogen. The chemical
reactions in combustion leading to peak temperature are supremely indifferent
to pressure. The temperatures and rates of normal IC combustion are
sufficient to cause most of the fuel and water present to be dissociated and
enter into the flame.

As can be seen above, water is most definitily not only not inert but is a
very active and important player in the combustion of hydrocarbon fuel.
Ricardo and others have documented that under certain conditions ( normally
supercharged ) water can replace fuel up to about 50% and develop the same
power output, or that the power output can be increased by up to 50% addition
of water. This conditions were investigated by NACA and others for piston
aircraft engines. It is important to note that these improvements came at the
upper end of the power range where sufficient fuel and air was available to
have an excess of energy that could not be converted to usable pressure in a
timely manner.

As a side note - Volvo recently released some SAE papers documenting the use
of cooled EGR to both reduce detonation and return to a stoic mixture under
boost in the 15 psi range - while maintaining approximately the same power
output. Notice - they reduced fuel and still get the same power output.

When you consider that EGR consists primarily of nitrogen, CO2, and water ( to
the tune of about two gallons formed from each gallon of water burned ), you
might draw the conclusion that it also was not "inert". They peaked their
tests at about 18% cooled EGR - which would work out to about 36% water
injection and got about the same results under similar conditions that the
early NACA research got.

----------------------------------------------------------------------------

 

Grumpy, from that research it seems as if EGR (cooled, does it make a difference?) will give you better gas milage. I see the cooling of the EGR that volvo did was to increase it's density.
The only other thing in question is it's usefulness at part throttle conditions. With my 25.6" tires and 3.73 gears my engine is humming along between 2600 and 2800rpm cruising on the highway in overdrive. Are those engine revolutions enough to "want" water injection? I'd like it better if I could read some actual research results and not just a bunch of generlized comments.
The Ohio State University Future truck team has integrated water injection in their turbo diesel powerplant with some sucess. They guy that was doing the testing with they dyno looked as if he wasn't getting enough data so I don't know how much of it was "fudged." You know, grad students are still students .
The only good thing about the diesel engine is that they didn't have to worry about spark so you know the results don't carry that questionable variable.
Next question; how much is alky per gallon? I like the idea of water for fuel economy and alky for power, or am I wrong with that assumption?

 

Reposting:

***********************
Be sure to goggle for NACA, In cylinder cooling, and if you can find a copy of Sir Harry Ricardo's High Speed Internal Combustion Engine, that would help. Also, Robert Harris posted a *paper* about what water does in the combustion cycle, over at DIY-EFI.
***********************

If you want to read the actual research ya gotta search to get it. That's why I posted where to look. That way, you get the ACTUAL RESEARCH notes.

 

On another note.
What makes you so sure it's about density?.
Or is about how well saturated the gases are with water vapor?.

 

I did the home-brew water/alky injection setup.. Was using winter windshield fluid, but I'm taking Grumpy's advice of the denured alky for next season.

I also decided to put an intercooler on the car. If ATI's charts are even CLOSE to accurate, I should be able to run about 15psi on this motor next spring with a 3 core IC. (and alky injection to boot).

I think I'm gonna o-ring my alum heads for extra safety.

-- Joe

 

Dunno if I'd be listening to that Grumpy guy....

I've been doing some **stuff** on the GN and just so happen to have a log from today. Note, low boost, just over 1/2 throttle (and then decreasing), and lean.
BUT, THE THING TO NOTE,
is that the MAT drops from 95dF to 59dF as the car gets going, and the intercooler really starts gett effective as the VSS builds.

25d timing, 91 octane, 15 PSI of boost.

The Syclone guys have more problems with kicking out the bottom ends, then with blowing headgaskets. 6 bolts per chamber is alot of clamping force. Not to mention it's nice having some fuses in the system, unless you have alot of money.

TimeStamp: 11/28/2004 - 11:08:04
Run Mph Rpm Map VE% Tps CTS MAT O2 Sa sPW DC% AFR rrWB
14 0 725 63 52 2 179 95 4 21 1.50 2 14.7 15.8
14 0 700 73 57 13 179 95 4 21 1.77 2 14.7 15.9
14 0 900 97 65 30 179 95 4 22 2.47 4 13.2 15.9
14 0 1225 96 85 32 179 95 4 23 3.17 6 12.8 15.8
14 0 1475 95 88 33 179 95 757 26 3.30 8 12.5 12.9
14 0 1725 93 89 35 179 95 664 27 3.39 10 12.5 11.9
14 0 1875 99 91 44 179 95 739 28 3.57 11 12.5 12.9
14 0 1975 100 91 49 179 86 748 28 3.69 12 12.5 12.3
Run Mph Rpm Map VE% Tps CTS MAT O2 Sa sPW DC% AFR rrWB
15 0 2000 101 91 51 179 86 770 28 3.69 12 12.5 11.1
15 0 2075 102 90 56 179 86 770 28 3.69 13 12.5 11.4
15 4 2150 105 88 58 179 86 677 28 3.69 13 12.5 11.1
15 4 2200 106 87 58 179 86 664 28 3.69 14 12.5 12.2
15 6 2275 110 84 59 179 86 655 29 3.78 14 12.5 12.4
15 6 2325 113 83 59 179 86 655 29 3.85 15 12.5 12.3
15 10 2350 114 83 59 179 86 602 30 3.81 15 12.5 12.3
15 10 2425 116 82 60 179 86 673 30 3.81 15 12.5 12.4
15 10 2475 119 82 60 179 86 726 30 3.91 16 12.5 12.6
Run Mph Rpm Map VE% Tps CTS MAT O2 Sa sPW DC% AFR rrWB
16 10 2550 122 83 60 179 86 425 30 4.00 17 12.5 12.6
16 15 2625 124 83 60 179 86 686 30 4.00 17 12.5 12.6
16 13 2675 128 84 60 179 86 704 29 4.18 19 12.5 12.7
16 16 2750 132 84 60 179 86 575 29 4.27 20 12.5 12.8
16 19 2925 140 83 59 179 77 726 28 4.39 21 12.5 13.3
16 16 3025 145 83 59 179 77 491 27 4.58 23 12.5 13.2
16 22 3225 155 82 53 179 77 535 27 4.97 27 12.5 14.0
Run Mph Rpm Map VE% Tps CTS MAT O2 Sa sPW DC% AFR rrWB
18 40 3800 205 80 47 179 68 717 25 6.26 40 12.5 13.7
18 42 3850 204 80 47 179 68 376 25 6.23 40 12.5 14.3
18 42 3875 201 80 47 179 68 668 25 6.13 40 12.5 13.8
18 43 3875 201 80 46 179 68 642 25 6.13 40 12.5 14.5
18 44 3925 200 80 46 179 68 633 25 6.13 40 12.5 14.4
Run Mph Rpm Map VE% Tps CTS MAT O2 Sa sPW DC% AFR rrWB
19 46 3925 198 80 46 179 68 350 25 6.10 40 12.5 13.8
19 49 3650 200 80 45 179 68 597 25 6.20 38 12.5 14.3
19 49 3575 201 80 45 179 68 695 25 6.26 37 12.5 14.4
19 49 3525 201 80 46 179 68 292 25 6.26 37 12.5 14.4
19 49 3525 202 80 47 179 68 611 25 6.26 37 12.5 14.1
19 51 3525 202 80 47 179 68 580 25 6.29 37 12.5 14.4
19 51 3550 202 80 47 179 68 332 25 6.26 37 12.5 14.0
19 52 3550 204 80 47 177 68 668 25 6.26 37 12.5 14.4
19 53 3575 205 80 47 177 68 646 25 6.26 37 12.5 14.3
19 54 3575 205 80 47 177 68 332 25 6.26 37 12.5 14.4
Run Mph Rpm Map VE% Tps CTS MAT O2 Sa sPW DC% AFR rrWB
23 76 3450 205 80 47 176 59 310 25 6.47 37 12.5 14.3
23 77 3475 205 80 46 175 59 588 25 6.47 37 12.5 13.7
23 78 3550 204 80 45 175 59 301 25 6.35 38 12.5 14.0
Run Mph Rpm Map VE% Tps CTS MAT O2 Sa sPW DC% AFR rrWB
25 85 2600 204 83 41 173 59 628 25 6.35 28 12.5 13.2
25 85 2600 204 83 41 173 59 708 25 6.41 28 12.5 13.0
Run Mph Rpm Map VE% Tps CTS MAT O2 Sa sPW DC% AFR rrWB
27 91 2775 205 84 41 173 59 341 25 6.47 30 12.5 13.0
27 91 2775 204 84 41 173 59 518 25 6.47 30 12.5 13.1
27 91 2775 204 84 41 173 59 699 25 6.47 30 12.5 13.1
27 92 2775 204 84 41 173 59 730 25 6.50 30 12.5 13.1
27 92 2800 204 84 41 173 59 350 25 6.47 30 12.5 13.1
Run Mph Rpm Map VE% Tps CTS MAT O2 Sa sPW DC% AFR rrWB

 

The denser the exhaust gas the more air and fuel will flow into the combustion chamber, it's the same idea as an intercooler, heat exchanger increasing power while decreasing fuel efficiency (more heat lost).
I don't understand what you're asking with that second question so I can't really answer it all that well.
I don't think the saturation would be all that important, it would vaporize before it got into the combustion chamber. I bet if they were agressive enough with the spark advance it would make a difference (before the water gets compressed into liquid form).
I really don't know what you mean Bruce. Do you mean that by cooling down the EGR they're seperating the water from the other gases? I don't see how this could help. I'm going to re-read that article and if I can get to Barnes and Noble I'll see if they don't have that book on water-injection. Either than or I'll buy an SAE paper about it.

 

I hear he runs 11s on a v6, yet my v8 couldn't get outta 12s.

Eh. I was sorta thinking that. Maybe better off machining the heads to accept those washers with the sleeve in them, so when I torque the bolts down it will be "permanent". I've heard of boosted guys with alum heads, and hte head actually lifts under boost and lets water into the oil!

Bruce, you running a IC as well as the alky ? or just the alky? was wondering if I should run the alky injection before or after the 3-core IC.

-- Joe