Water Carburator
 

I have been interested in water injection on and off for years, I just read the article on the Auqa-tune and it just kind of hit me.

Why not put a water feed carburetor in line in between the intake manifold and the air filter-MAF unit.

There are bubbler, spray, and air water injection systems out there, but from what I see you either you get a vacuum leak or engine drowning. It seems the flow can't match the intake air curve for the engine. So this is when it hit me, run a small water tank and an MG style thumper fuel pump to pump water into a carburetor. Have linkage to sync operate the butterflies on the carb and the throttle body and viola, you now have a metered atomized flow system thru the rpm range. No air leak, no drowning, you can even leave the accelorator pump hooked up for a blast of steam. Combine all this with an HAI and I think water atomization can show some super benefits.

I know my Solstice has a thing about humidity and water, GM uses a type of what they used to call a Hot Wire MAF unit, get this thing wet and the engine goes into safe mode untill what ever dries out. The Solstice has a washable factiry air cleaner, put it in the engine wet and the MAF freaks out and the car will only do 25 mph. This relates to the placement of the caburetor between the MAF and intake manifold.

Also I noticed a huge drop in mpg last week when it went from 70 outside to 50 and the humidity went down to 9%. My car went from 29 mpg to 26 mpg, so I started thinking of ways to ad humidity to the engine.

Now as far as caburetors go, there are 2 bbl down drafts, or perhaps a large SU carb from one of smog year MG's. Another big side draft SU would be a Rover 3.5 V8 carburetor. You'll have to play around with jetting and ad antifreeze or alcohol to the mix in winter, but I think it could work.

Best of all its free, new carbs are super expensive and all this technology is out there in junk yards for the picking. This is not reinventing the wheel, so theres no money to be made reinventing the carburetor. When I get my next used car, it will be a rolling mpg laboratory, I can't wait.

Your thoughts?

My thoughts are: I suspect the drop in temperature had a much greater impact on your fuel consumption than the change in humidity.

EDIT: that said, I did hear some anecdotal info about DIY water injection just this week.

His car failed his smog test due to high NOX and unburnt hydrocarbons, so he added water injection through the EGR circuit ... and passed the next test with flying colours having made no other changes.

He left the water injection on following the test, but noted no change in fuel consumption.

(Of course nothing he said proves anything either way.)

I agree. Lower temperatures = greater fuel enrichment until warmed up.

You also don't generally get something for nothing with water injection that proper fuel and ignition tuning cannot correct, unless you are talking about high boost turbo/supercharged motors.

It would decrease economy by decreasing power output without affecting the amount of fuel output by the injectors...

Water Injection does not add power, it is an anti-detonant period.
It is useful only when paired with combustion chamber conditions that far exceed the stability of the given fuel.
Secondarily it helps by cleaning the combustion chamber and general valve area of carbon.

So.... Unless you're running very high amounts of static compression and/or charge temperatures that grossly exceed your fuels ability to pre-ignite under light loads, it would not be useful.





It would also destroy cheaper quality MAF's... aka Ford, GM, Nissan, while at the same time shorting out any IAT, or MAF sensor it comes in contact with. Remember that at some level it will be coaxed backwards up the intake...

Please quantify that statement please.

water injection flat out decreases power until the fuel is operated beyond it's original pre-ignition limit.


you put wi on an engine that has no pre-ignition problems in the first place and power simply drops. less power is being made for the same amount of fuel being burned.

How is less power being made?

wi is not a fuel, it is a cleaner and an anti-detonant.
on an engine that is NOT experiancing power loss due to pre-ignition, running pump gas + wi will have the same end result as trying to run 105-110-115 octane pump race fuel in it.

the engine will:
drop power
drop economy
bog on tip-in throttle enrichment

Like I said before, how will it drop power? Assuming of course reasonable amounts are used. Hydrolocked engines make no power. ;)

using fuel that is more stable than required always lowers power output. the only way to offset that is by running the more stable fuel it out of conditions the less stable fuel can be run at.

you put race gas in a stock engine and it'll drop power, economy and throttle response. the flame front is too slow, and the overall entire combustion process simply takes too long. all of that fuel that can't be used in the meaningful portion of the expansion stroke simply flies right out the exhaust pipe
the exact same thing happens when you put water injection to an engine that can't benifit from a higher octane fuel.



most things associated with water injection are complete myths:

• the state change is meaningless in the combustion chamber!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! (it does not create some magical steam power to push the piston down...)
• wi does not appreciably cool the incoming charge temp (it is exposed in the charge for milliseconds before entering the combustion chamber, while the thermocouple you shove in the intake tract trying to "prove" it does cool it is exposed to evaporative cooling in an extremely high velocity of airflow for aslong as you want it exposed...)
• the amount of air/fuel displaced is inconciquential
• wi cools the various combustion chamber faces itself only a small amount at most

water injection is, and never has been anything more than a cheap means to raise the effective pre-ignition resistance of the fuel you're using. it's the poor man's race-gas.






If you're not running an engine that experiences pre-ignition <cough>forced induction, or a grossly high effective compression normally aspirated engine <cough>.
you don't need a higher octane fuel, race gas, or water injection.

exactly. you use it when pre-ignition is present, or there is a great fear of it.
i.e. taking your force induced (turbocharged, supercharged, or n2o injected) engine to the limits (or just a stupidly high effective compression normally aspirated engine) without using expencive $4-7/gallon, limited supply of race gas (commonly avalible in 100-102-105-110-115-120 octane), or ethanol.

ethanol i hate. it's completely communist. wich ever moron dreampt that up should be shot.
you're correct in that ethanol can also solve pre-ignition problems. It may have only a small portion of energy gasoline has, but it's only real upside is that it equates to about 105-115octane gasoline all things depending... so while it's completely crappy to run an engine off of, with foced induction it's atleast on equal terms with gasoline in power production once you push it beyond the normal pre-ignition limit of common 93-94 octane pump gas

More stable fuel, what are ya talking about? Increases in octane do not decrease efficiency provided the auto is already running w/o autoignition. In and of itself, octane is just something that indicates how well a fuel resists autoignition, or how high it's activation energy is.
My experience reflects that running higher octane gas in a vehicle that doesn't need it has no noticable effect on efficiency either way. That being said, efficiency, as in mpg, depends on the fuel formulation assuming no autoignition problems. Saying race gas will make an engine more inefficient, likely because it has less energy per gallon, is as silly as saying a CI vehicle is more efficient than SI because diesel has more energy per gallon than gasoline. For instance, M-100 (Can be used as a race fuel) only has ~57k btu, while gasoline has nearly double that. Just because I use M-100 in my car and get half the mileage doesn't mean the engine is operating relatively inefficiently.

So, like I asked before, how exactly does reasonable water injection reduce power during normal driving conditions?

I think it's just a collusion of terminology. More stable meaning slower to burn.

It depends on what conditions you assume here. I.e., with all else in the tuning being exactly the same, higher octane fuel will not burn as efficiently in a motor tuned to run on lower octane. Assuming that the timing can be adjusted to take advantage of higher octane, there really should be no difference in efficiency. So most likely, if your car gets the same economy on higher octance fuels as the lower ones, it is automatically adjusting it's ignition mapping for best combustion. On the other hand, people driving dinosaurs like my Tercel with distributors and low compression would likely see a slight decrease in economy with higher octane unless we manually correct the timing. That is where the loss of power from water injection would come from.

Bottom line: It can't make more power vs. a proper tune on gasoline alone, but it can reduce it - depending on what compensations you or the motor fail to make.

Take some water and put a lighter to it.
Let me know when it burns. :p

So my Carb'ed pickup truck shows no noticable difference in efficiency because it adjusts timing? ;) I see what you're saying, but it's a bit of a fallacy since I was talking about normal driving conditions and changes in octane. In other words, if I just change the octane, and leave everything else stock, there shouldn't be any difference between performance. Higher octane won't do reduce combustion efficiency, all things being equal, unless it gets to the point where it's so high it can't be ignited by the plugs. Now, that being said, most modern vehicles can take advantage of high octane fuels in order to improve efficiency, but, that's not what I'm talking about. :thumbup:

By that argument, having anything except for pure Oxygen in an engine reduces power, but in reality this isn't the case. Provided there isn't too much water in there, an engine will make a certain amount of power provided it has a certain amount of air and fuel. Adding a small amount of water during most operation (throttled) won't do much (either way imo) to combustion or power since there's still the same amount of air w/ the same amount of fuel making the same amount of power. Er... NVM. What theclencher said.

P.S. There is a very specific reason why water injection alone doesn't improve eff, but I haven't seen anyone mention it so far. :p

Have you all read about the 6 cycle engine where water is put into the cylinder which turns into steam and creates an extra power stroke?

I am curious if there would be a small affect of this with putting water in on the normal intake stroke causing any steam buildup helping economy. Or maybe cooling down the cylinder while you are trying to create a big boom isn't good...

Think about it guys, if FE increases with humidity, couldn't you just put steam into the intake manifold? the steam could be obtained by wrapping copper tubing around the exhaust manifold. steam=water vapor, water vapor=more dense air, more dense air =better FE?

It sounds like you've just had one tank lower than the last which I woulnd't worry about. try some more consistent and controlled testing, don't go running off half cocked with ideas because something happened once.

The best use I've seen for water injection is cleaning engines (followed by an oil change (water blows by a lot) and high power engines as an anti-detonant. like everything else in the engine, it does have to be tuned...extensively as the gas. it's effects will vary with rpm, charge quantity (turbo/superchaging), charge temp, mixture, etc. My own dabbling around with it has shown higher octane does not benefit an engine not tuned to use it. I get better power, response, mpg using premium because I have my ignition advanced nicely. the advance gives the goodies, octane allows it to happen. Just like WI...if everythings running fine, it wont help

What I meant about putting steam into the air intake isn't really to add water, but to add water vapor, to make the air more dense, giving more "oomph".

Is't steam heat? hmmm..

My major argument is this: The engine throw off lots of waste energy in the form of heat. Using the heat to vaporize water inside the combustion chamber should generate power. Cool engine, generate power.

Yes, the flow rate is critical, and it probably doesn't work until the engine is completely warmed up and opening the thermostat (which mine does often due to the grille block). My system will feature a needle valve to control the flow precisely. A soon as I get a few minutes, I will write an update on my experimental system's progress in the Water Injection thread below.

Jim, that's my thought exactly, but remember just because you're absorbing heat does neccessarily mean you're increasing the efficiency. You could have some water become water vapor and lower the temp of the exhaust from 1000F to 800F but if it's 800F with 20&#37; steam that's the same energy content because of the latent heat of the steam versus the latent heat of normal air, etc.

But yes, the 6 cycle engine and use of a LOT of water to generate a LOT of steam will move a piston, but timing it right and using the right amount of water will be very hard. Having 5-10% water vapor in the charge will not generate enough steam to move a piston at all.

So I would love to see your experiment, I cannot see it hurting beyond lowering your intake charge too much or causing the fuel to burn to slowly. I really think the only way water injection will prove useful is by using direct injection and injecting a LOT.


And lastly, to comment on higher octane, it is slower burning and resists ignition. Some of my cars improved slightly with it and some decreased MPG with it. Some didn't seem to make a difference but ran hotter, exhaust headers glowed brighter at night, etc. What others have been trying to say is that if your ignition is timed perfectly so that just before BDC (bottom dead center) of the power stroke it fully completes burning the entire charge and then you put in fuel that will not have enough time to fully complete burning before BDC, you will lose efficiency. You will lose power anyway (assuming higher octane/race fuels really have less energy content as stated above), but you'll lose efficiency too because you're not even capturing all that energy for work, it's burning slower and burning in the tailpipe instead of the cylinder.

Yeah the water adds cooling to the combustion so it in effect cools the engine and the burning of the fuel at a lower temperature - it should also provide about a 600 to 1 expansion of water to steam which is supposed to add to the cylinder pressure and improve efficiency since water expands more than air when heated up to steam temperatures. It also cleans carbon which is why I ran it in my 65 Rambler American with a flat head 6 which used to carbon up a lot in the squish area of the combustion chambers. Too much water injected will put the flame out - water at too low an engine temperature will make rust form in the engine - you also run a little risk of getting more water in the oil from blowby. The MAF (Mass Air FLow) sensor is usually a electrically heated wire or chip (ceramic) that is cooled by air flow - more air flow more cooling and that indicates more fuel needs to be injected - HOWEVER if doused with water it also cools the wire/chip and results in excessive fuel being injected and you get rich mixture and O2 sensor feedback which will generate a CEL.
So the trick is to inject water at the proper engine operating modes where it does good and not when it is not needed like idle - engine braking - light throttle - cold engine temps - just before shutting off the engine.

If anyone's still thinking of adding water injection after all this hoohurah, here's my favorite DIY water injection system:

https://www.3barracing.com/waterinj.htm

And here are plans for a nice little controller which will wait two minutes to turn the system on after startup, turn it off at idle, and then wait two seconds to turn it back on again when you take off:

https://better-mileage.com/memberbonuswateradx.html

Sorry, I don't feel up to hiding the links in html code this evening :o

Update: I am done with the following:

- Welding baffles to bottom of PE/PP feed tank w/ old soldering iron
- Attaching Suction Diptube, Vent Filter, and Recycle Bulkheads to top of tank
- Welding top of tank back onto body of tank. Hydrotesting revealed one small hairline leak, which I repaired.
- Attaching redundant pump suction strainers to assembly.
- Hooking up pump, needle valve, and nozzle with temporary tubing for wet testing. $4 hardware store 1/8" FPT needle valve did not reduce flow through nozzle noticably (even at 1/2 turn above 0&#37; open), so I bit the bullet and bought the $19 panel mount precision needle valve from McMaster-Carr. This valve is intended for Pneumatics but we'll give it a go.

Next steps:
- integrate universal fuel line filter (paper media)
- test precision needle valve control
- mimic plumbing setup (as it would be in the car, minus vacuum) as closely as possible, to duplicate pressure drops
- characterize system by catching discharge in a 1-gallon milk jug, i.e. "at 1 turn above 0% open needle valve, the system dispenses 0.1 GPH", "at 2 turns above 0% open needle valve , the system dispenses 0.2 GPM". That way I can have a calibration curve without resorting to expensive Rotameters to see the flow rate in realitime.

interesting...

i'm still struggling to put together a far more basic system...

initially i'll have a pe tank with a bubbler and a line to a vacuum port of the carb above the throttle valve...

i'm considdering useing a bicicle tire valve as a one way valve to keep the bubbler working for a while after the intake cacuum has disapeared. it that works i might try to advance timeing a little.

second setup will be similar but will relocate the bubbler to a copper boiler tube that is heated by the exhaust...

the goal is to have a simple reliable system that allows me to run lower octane fuel and advance timeing

Jim Dunlop: what's the best way to weld pe? just put the bits together and heat them or use a 3d scrap as welding substance? seems like a very usefull technique, but i'd hate to waste all my good containers finding out how to do it. :)

That's exactly how to do it. Put the piece you want to join together, and use a strip as a "weld rod" to add material. This is necessary to fill in the cracks and make up for the slight deformation that occurs to the pieces you are joining.

The key is to make sure you use EXACTLY the same material. As I learned in college, polymers DO NOT like to mix with each other -- even if they're both commonly called the same thing such as PE or PP. Make sure, at minimum, the materials have the same recycling code number, unless it's 7 (like the red gas can I am using)...then you need to buy a duplicate product to cut up for construction pieces / weld rod.

Also, don't dwell too short or you won't get fusion...and don't dwell too long or you'll get too much deformation and potentially thermal decomposition (burning).

thanks, also for the waring of the different pe kinds.... i assumed this would not be the case... i've seen white pe containers with a transparent fine running the length of the bottle to check fluid level... but obviously mixing different bottles won't be that easy...

i'm one more part (t-junction for the vacuum hose), and some spare time away from testing my first primitive setup, so hopefully i can get this working soon.