WATER INJECTION??

[5030]

Okay, it's time to pick the collective brains at TBYNet.

I was reading in some magazine a while ago about putting water injection on automotive gasoline engines to improve the fuel mileage.

I remember in the 60's, during the gas rationing, putting water injection on high compression engines to reduce spark knock from running regular gas in a premium gas engine.

Anyway, I went and installed a water injection unit on my farm car, a 1994 Suzuki Sidekick (not a high compression engine by any means).

I made a really simple and cheap unit. I purchased a quart refrigerator bottle with a screw on lid and a snap spout, and aquarium starter package (air stone, vinyl tubing, 2 needle valves and 2 tees). Total cost: $4.00 I also purchased a gallon of distilled water and a pint of 99% isopropyl alcohol. The alcohol keeps the water from freezing here in Michigan (it's winter).

I teed the feed line into a ported vacuum line running into the plenum that feeds the intake runners for the fuel injection unit. I regulate the water feed with a needle valve. I consume about 1/2 pint of water mixture a week.

Here is the best part.........

My mileage was about 30.5 for city driving (back and forth to work). That's not too bad really, but....
My mileage jumped to 35.0 in the city. The engine "feels" peppier and it starts much easier. I had a decided deceleration flat spot about 35 mph. It's gone.

My question is why?

I don't understand what the water is doing inside the engine other than it works.

Any thoughts on this??

 

[bgott]

Why? The water has done a thorough de- carboning of you engine. It's probably steamed all the carbon out of your catalytic converter, also. De- carboning is good! /forums/images/graemlins/smile.gif

 

[RanchMan]

<font color="blue">I teed the feed line into a ported vacuum line running into the plenum that feeds the intake runners for the fuel injection unit. </font>

Probably my brain just failing to engage, but I'm having a hard time picturing this (sounds simple enough). Do you have a small diagram you could attach for us to see (and perhaps copy?? /forums/images/graemlins/wink.gif )

 

[5030]

bgott:

Should I leave it on the engine and continue to meter the water in or should I take it off? If I take it off, will the mileage stay up or drop back to the previous level.

The car never got that good of mileage, even when it was new. It has over 200K on it now. Do you think the water will contaminate the oil or cause a failure of some part internally?

 

[5030]

RanchMan:

I'll take some pictures. Besides, I want to post a few pictures of the new snowblower. I probably won't need it though.

 

[5030]

RanchMan:

Here is the first photo. It's easy to see how I hooked it up. In this one, you can see the bottle and the hoses. One hose vents the bottle so the vacuum doesn't suck the sides in and the other goes to the needle valve and on to the vacuum port.

 

[5030]

This is the second photo:

This shows the hose routing as well as where I teed into a vacuum port on the fuel injection plenum.

 

[5030]

This is the third photo:

Another view of the hose routing. I used the ported vacuum that purges the charcoal cannister via a vacuum operated valve. I teed in right above the valve with a short length of vacuum hose.

I used clear tubing on the hose routing from the bottle to the vacuum port so I could see the water flow so I didn't have too much or too little.

 

[TresCrows]

Water injection has been around a long time. During the days of radial engines water injection was used to increase power and decrease the chances of detonation. It increases octane and as it flashes to steam there is some power derived since that flashing to steam absorbs heat energy that would normally escape out the exhaust. This effect also reduces cylinder head temperatures. The aircraft had water tanks for the injection. Race cars, drag racers etc have also used water injection as well. Yes, it will contaminate the oil and cause all sorts of problems in engines not intended for such use. I doubt the increase in mileage is sustainable.
I had a souped up SVO Mustang /forums/images/graemlins/smirk.gif. It had an aftermarket computer chip that allowed up to 21 PSI boost. The engine had been heavily modified--professionally at a cost of nearly 15,000 dollars--- and produced over 300 hp on a dyno--rear wheel. This was from the 2.3 litre turbo 4 banger. It had a factory intercooler and water cooled turbo which I increased in size. A button on the shifter applied nitrous and water -- my own primitive design. Pushing the button probably resulted in another 50 horses--never dynoed that feature. I also used a double nozzle mister--self fabricated using the mister nozzles from a patio mister to spray water vapor on to the intercooler fins to further cool the incoming air. The same type mister nozzles are what delieverd the water vapor to the engine intake. When there is a change of state of matter, in this case from liquid to vapor, there is a cooling effect, a small amount of water vapor hugely increases the density of the incoming air. Nothing on four wheels that I did not want to pass me ever passed me. The engine blew and I rebuilt it using serious parts and it ran even better. The car was destroyed in a hail storm that so damaged the car it was totalled by the insurance company. The windows were torn out, the leather interior was shreaded, the metal was pounded down to the inner stampings. To this day, my house, which I still own, back home, there are the remains of the burn out marks where I would lite the Gatorbacks up each morning on the way to class /forums/images/graemlins/grin.gif. J

 

[nomad]

Lets see what you are doing by combustion chemical formula and if you are doing good or not by adding the water.

You are burning a kind of HydroCarbon (fuel) which can be formulated as HxCy where H=Hydrogen, C=Carbon and x and y are some numbers (depending on the fuel type.) You burn it using oxygen in the air. (ok ok, you know all these from simple chemistry, but I need to repeat it here to understand the effect of the water.)

Combustion reaction:

HxCy + Air (O2+N+etc) --> Exhaust (CO2+CO+H2O+etc+heat)

So? So, this means that the water H2O is already involved throughout the reaction. Adding some more H2O into the engine isn't different than operating the engine in a humid climate. So, the engine shows better performance at humid climates? It depends. If you look at the combustion reaction formula above carefully, there are carbonmonoxide CO and heat at the exhaust which are not wanted. Adding some more Hydrogen H by adding water H2O will help reducing CO amount at the exhaust? I'm not sure about this as I am not good at the chemistry. But, "the heat" amount exiting at the exhaust will certainly reduce. This means the lower temperature difference between input and output of engine and this means engine is closer to "balance" (according to entropy rule) and this means the performance of engine is better. Note that the "perfect" engine operates at zero temperature difference, that is, zero temperature difference between inlet and outlet manifolds. I can't think of other reasons on why you got a better performance. By the way, I don't think the disintegration of water molecules H2O into H and O2 as the engine combustion temperature (about 1500 C~2700F) isn't high enough for that reaction. But again as I said I'm not good at chemistry.

By the way, becareful about oxidation (sp?)