Thoughts on water injection

Groo2 · **Posted:** Tue Jan 29, 2008 4:27 pm

Some thing I have been kicking around in my head.... on a couple of occasions a few members here have opted to put a tuning module in vs the inmotion tune. The primary reason being they want to be able to pass emissions in the future. Now it is my understanding that most emissions look for NOx gasses, and these are primarily produced when the engine is running hot (sustained high rpm's). So if you add a water-methanol injection kit to this mix (at a very moderate level) it would, in theory, keep the temp down and thus reduce the NOx gasses that would otherwise be produced. A hopeful side benefit would be (if you stay off the go pedal) a moderate increase in fuel economy. Please let me know your thoughts on this, if I am wrong someone please set me straight.

Thanks,

Groo2

Joe Romas · **Posted:** Tue Jan 29, 2008 7:43 pm

You could also blow the cylinder head right off :shock:

warp2diesel · **Posted:** Tue Jan 29, 2008 8:27 pm

Over fueled diesel engines of the past had problems with carbon building up in the cylinders. Under some conditions the carbon would build up on the top of the piston causing it to against hammer the cylinder head. Water injection would help clean these deposits off the pistons and help lower the HIGH EGT TEMPS caused by over fueling. By adding water injection (methanol was added to prevent the water from freezing up) to an over fueled engine the horse power and torque would increase with out suffering from meltdown.
Since our CRDs run clean, have inter coolers, common rail ECM controlled injection and are not over fueled, water injection would be of little benefit.
Since most of us have the JEEP attitude and will not run from a pouring rain storm, driving in a strong rain storm may provide all the moisture we need to clean out our cylinders of carbon. Doing the ORM will reduce the ingestion of carbon from the EGR and further lower any potential benefit from water injection.
On the other hand, if you are going to crank up your Cummins 5.9L to 1000 HP, water injection would definitely be a benefit.

Steve

gmctd · **Posted:** Tue Jan 29, 2008 9:37 pm

On the other hand, he wasn't talking about carboned cylinders, usually found in a Diesel engine pumping lots of crancase oil thru the cylinders (another reason not to pour waste motor oil into your fuel tank, BTW!) - he was talking about reducing cylinder temps in order to reduce noxious oxides, and water\meth is a good method of doing just that thing, as mentioned, even better than EGR for obvious reasons, particularly in a Diesel engine, even moreso in a turbocharged Diesel engine where there is always a beaucoup of oxygen molecules left over after combustion - it is also used for charge-air cooling, in lieu of a heat exchanger - some toss it in at the turbo inlet, which, of course, erodes the blade surfaces - others use a post-turbo method of pressurized injection, using Boost pressure to control injection pressure on the nozzle(s).

The reason it is not used more than EGR is a.) EGR is free (ignoring the displayed numbers on the pump when you're replenishing the source of those exhaust gasses), where WM is another consumable to replenish and manage, and b.) oxidation

Particular care needs to be excercised, as we have the aluminum c-a cooler, intake manifold\engine cover, and aluminum head - in any instance of slight dis-use, the water\meth solution causes rapid oxidation of any aluminum surface exposed to it - it is worse in a Diesel engine because the light oil we use as fuel never touches any surface outside of the intake valve - there is nothing to wash the intake path down, protecting the surfaces from the chemical mix, as our intake is (hopefully) pure atmosphere, unlike a gasser (patooie!), where the fuel is trucked in with the intake air charge

So, yes the idea is a good one, and much data can be found on the internet for assembling a WM injection system - but it can cause much headache unless carefully managed due to the large chunks of auminum sitting above our iron block.

Groo2 · **Posted:** Tue Jan 29, 2008 10:29 pm

gmctd,

I say this in jest only, you stated that something to wash the WM mixture off of the aluminum construction would be helpful..... so then I should pull off the provent, and put on a WM injection kit.... man some one was really looking forward by allowing all that oil to get sucked in the the CAC... :wink:

Joking aside my experience is rather limited, so it is time to go off and see if I can find some reasonable means of arresting the WM resultant corrosion, or see if there is a magic ratio of W to M that would not result in oxidation, but still be enough of a catalyst to lower the NOx?

gmctd · **Posted:** Tue Jan 29, 2008 11:06 pm

Agreed on that!

But, yeah, the info is out there, just takes a quick search to get it - note that some are using the WM for charge-air cooling without a physical heat exchanger, others are using it to enhance one for increased Boost pressures, with resulted increased Boost temperatures - others for reduction of cylinder temps - the mix is determined by the end purpose, so there should be enuff data for you to get a specific blend - FYI - the 60-63 Oldsmobile Starfire used WM injection to cool their little hipo all aluminum turbocharged 215cuin V8 - many were ruined because careless drivers wouldn't manage\service the reservoir, some probably due to Oldsmobile's high charge for the alcohol - me, I used windshield washer fluid, even tho the service manual said no - betcha I had the cleanest cylinders in town, eh

DarbyWalters · **Posted:** Tue Jan 29, 2008 11:28 pm

I used to use a "Miller Woods" stand alone injection system with my Mazda Rotary Turbo...of course the "injector" injected fuel but it served the same purpose. I mounted it just after the intercooler on the downstream pipe before the intake. The air from the intercooler still made the tube hot to the touch after it exited the intercooler...but after the Miller Woods you could grab the tube anywhere behind the injector.

I would think with a separate water tank you could use the same setup for our CRDs. You could also adjust the amount of fuel (water in our case) on the fly from a cabin control.

gmctd · **Posted:** Tue Jan 29, 2008 11:50 pm

Holy cow! at first read, thassa very scary thought, pressurizing raw fuel for injection into the pressurized intake duct, especially prior to the throttle plate! Talk aboutcher backfire - or would that be frontfire - on the other hand, the pre Grand National Buick engines were turbocharged using a Rochester 4bb carb bolted onto a special manifold, which was bolted onto the inlet of the turbo, which was bolted onto the intake manifold, with the raw gasoline vapors hitting the blades of the turbo to be boosted into hot pressurized fuel, just waiting for a likely incident - scary, but fast for a V6-powered MonteCarlo sized car

Anyway, some are even spraying water mist externally over the c-a\c for extra thermal capacity, which also helps NO a teeny bit, but direct-injection is way more effective, because not only do we have CO trying to make NO, but we got plenty of O willing to get in on the act.

Pablo · **Joined:** Thu Feb 02, 2006 10:06 pm **Posts:** 1201

When I thought of doing this I planned on using the windshield washer tank and making it pull double duty. I just did not see any room under there for another tank. After the aluminum concerns, I forgot about it. Plenty of other things to spend cash on before I worry about that.

nursecosmo · **Posted:** Mon Feb 04, 2008 12:43 am

This place has one of the better systems and is priced right

http://cgi.ebay.com/ebaymotors/WATER-IN ... ercharger_
W0QQcmdZViewItemQQcategoryZ42604QQihZ014QQitemZ330208852034QQrdZ1QQsspagenameZWDVW

Water injection has a different effect in diesels than in gas engines. besides EGT reduction there is also an increase in HP if the amount of H2O is tuned properly. If the water is wanted for charge air cooling a fine mist is desirable in order to vaporize and get max cooling. But if the water spray is more course and droplets are still intact as they enter the cylinder they explode into steam when heated by compression and burning fuel and can add significant energy to the piston face especially towards the end of the stroke.

Thoughts on water injection

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