water injection to cool charge air

JohnEd · July 26, 2011, 09:15:21 PM

There is supposed to be a driect benifit reduction in exhaust temp for reducing the charge air temp. Degree for degree? Dunno. Water injection cools gas engine combustion temp and exhaust and that seems to be well proven. Would we benefit from water injection with a DD? Any ideas on dealing with mineral deposits?

Thanks,

John

JohnEd · July 28, 2011, 12:07:20 PM

Now these guys say they are injecting meth also but I wonder what straight water would do for you?
http://www.snowperformance.net/dyno_chart_view.php?type=diesel&dck=20

John

JohnEd · July 28, 2011, 12:17:57 PM

These guys seem to have nimbers on intake charge air, combustion and exhaust temp reductions.

http://www.alcoholinjectionsystems.com/Turbo-Diesel-Systems/c26/index.html

JohnEd · July 28, 2011, 12:33:16 PM

These guys seem to sell it all.

http://www.parleysdieselperformance.com/t/categories/chemical-and-water-injection

JohnEd · July 28, 2011, 12:43:00 PM

Not that figuring it all out is a challange:

http://hackaday.com/2005/06/25/home-built-water-injection/

JohnEd · July 28, 2011, 12:50:23 PM

I tried to get the "junkman" to comment on why water injection was such a "Swine Flu" bad idea but didn't get a post from him. His many years of experience should have shed some light was my thinking. Didn't happen. Still, i want to post his comments so any that are of like mind might share information:

Quote from: junkman42 on May 17, 2009, 04:36:21 AM
As an older retired military person that spent many thousands of hours flying on aircraft with reciprocating engines My personal experience is that what We called ADI means simply water and alcohol injected at METO power to prevent detonation at high power settings. Detonation in this context means preignition. At high boost pressures even with 115/145 octane aviation fuel ADI prevented cylinder failure at high power settings usually meaning takeoff power. 60 inches of manifold pressure is a feared thing on a hot day with maximum weight etc. Propane injection is a totally different principle with diesel engines. For information buy a copy of one or more diesel enthusiast magizines. Water injection with a diesel engine should be avoided like the swine flu viruses. Regards , john

Johned

TomC · July 28, 2011, 09:39:26 PM

On ship sized Diesel engines, water injection is used to lower combustion temperatures to lower Nitrous oxides. On our relatively small Diesels in our buses, I would not fool with water injection. True the right amount will lower combustion temperature, but inject just a bit to much, and you could get hydro lock bending a rod, blowing the head or blower, etc. Personally- I wouldn't fool with it. If your engine is turbocharged, get a good quality air to air intercooler custom made to your bus-it will be the best thing you could do. I sell big rigs (Freightliner and Western Star) and I have yet to see any of the big Diesel engine manufacturers (Caterpillar, Cummins, Detroit Diesel, International, DAF, MAN, Volvo, etc) have the option of having water injection on their engines. If it worked so well-don't you think the engine manufacturers would be using it-how simple would that be? Good Luck, TomC

JohnEd · July 29, 2011, 09:36:01 AM

Quote from: TomC on July 28, 2011, 09:39:26 PM
On ship sized Diesel engines, water injection is used to lower combustion temperatures to lower Nitrous oxides. On our relatively small Diesels in our buses, I would not fool with water injection. True the right amount will lower combustion temperature, but inject just a bit to much, and you could get hydro lock bending a rod, blowing the head or blower, etc. Personally- I wouldn't fool with it. If your engine is turbocharged, get a good quality air to air intercooler custom made to your bus-it will be the best thing you could do. I sell big rigs (Freightliner and Western Star) and I have yet to see any of the big Diesel engine manufacturers (Caterpillar, Cummins, Detroit Diesel, International, DAF, MAN, Volvo, etc) have the option of having water injection on their engines. If it worked so well-don't you think the engine manufacturers would be using it-how simple would that be? Good Luck, TomC

Tom,

Not to argue with you...especially given you experience. The "but" that follows isn't anything more than additional comment and question.

The info on the ship's mamouth D plants using water injection is, of course to me, news. Not knowing, I wonder that ships need to meet any sort of air quality or efficiency regulation that would lead them to water injection systems for air quality motives. That leaves efficiency and power as the rationale. The mfr.s of the automotive systems have an abundance of info concerning power/efficiency increase. From what I gather, you get a power bump for a given volume of water injection and you get more for an additional increase and there must be a optimum ratio per given engine. My point being that you can get some benefit for a small, less than optimum, injection quantity. In my life experience, taking it to the "limit" has associated risks and down sides.

I have emailed a couple of these companies about the benefit of straight water injection sans meth but haven't, as yet, gotten a response. Junkman, as well, hasn't responded with a clarification of his post. I hope for some feedback, still. Your sharing sure makes you stand out, at least at this point.

"Hydra lock" is, as you pointed out, a disaster. Long ago I was told that injecting water into the intake charge air stream would cause the valves to warp. Throwing caution to the wind I ran a stream of water into my heavily used and abused VW engine to remove carbon. I did this every few months to correct "ping" on heavy and prolonged load. It worked and when I tore the engine down the second time I found it pretty much carbon free.....anywhere. Never bent valve but I am not taking issue with that caution. In this case, I think we are talking about very small quantities in comparison and even then only at high throttle settings.

I cannot imagine anyone arguing with the wisdom of a quality and properly sized Inter cooler. Leave no doubt that I share your opinion. I am not in any way implying that the IC should be eliminated. I could see where if water injection was part of the design you would require a smaller IC to achieve the same charge air temp drop. But why not get the max for the max and design for non-water injection.

These guys talk about water injection but in reality they mean "water vapor". Liquid water isn't introduced to the combustion chamber. They either finely atomize the water near the engine intake or more crudely break up the stream of water and introduce it prior to the IC. Regardless, liquid water isn't intended to reach the cylinder.

I can't get on-board with your rationale that the Big Guys not doing something proves much of anything. They didn't use catalytic converters, or uric acid injection, nor EGR nor retarded exhaust valve timing or even all those fancy injectors....not to mention high fuel pressure Common Rail till they were forced into it. Even low sulfur, despite the obvious benefits, was forced upon the manufactures. And let us not even go to lead as a topic. They are motivated by more complex "stuff" than "is it a good idea" or will it really work. Lots of stuff in the decision mix even besides Gummint meddle'n.

Thanks for your info Tom. As usual, I hadn't a clue.

John

JohnEd · July 29, 2011, 09:59:09 AM

This feedback seemed worth posting. Note my question about application.

Hello John,

We don't sell kits that are exclusively for water injection. We do carry water-methanol injection kits, and they would work well with only injecting water. Here's a link to a couple different kits for you to consider:

http://www.parleysdieselperformance.com/products/snow-performance-universal-diesel-stage-1-boost-cooler

http://www.parleysdieselperformance.com/products/snow-performance-universal-diesel-stage-2-boost-cooler

http://www.parleysdieselperformance.com/products/snow-performance-universal-diesel-stage-3-boost-cooler

Please let us know if you have any other questions.

Thank you.

Support / Parleys Diesel

On Thu, Jul 28, 2011 at 12:33 PM, <noreply@parleysdieselperformance.com> wrote:

Name: John Grabe
Email: jegrabe@gmail.com
Phone: 541 915 0832

Regarding: Sales

Make: Prevost
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Year: 2001

Message:
I am interested in installing a water injection system on my 8V92 DD. Can you make kit recommendations and such?

I am very interested in using water alone for injection. What kind of performance can I expect from that? Intake air temp and exhaust gas temp are of particular interest.

Thank you,

John

junkman42 · July 31, 2011, 10:05:42 AM

John Ed, the injection of water and methanol into a aircraft recip engine is for a different reason than water injection into a diesel! There is a excellent article in the current issue of Diesel Power Magazine on water methanol injection for diesel engines. I would recommend this magazine for a lot of reasons if for no other reason it gives a person a lot of information on diesel performance which differs in principle in many areas from gas engine operation. If you inject water into the intake of a diesel engine it needs to be downstream of the turbo and in My opinion down stream of the blower. I think water should only be injected into a engine that is at operating temperature and terminated before shut down to preclude the possibility of a puddle forming that could be ingested. I would also wonder what effect water injection would have on lube oil in areas such as acid formation! John L

JohnEd · July 31, 2011, 12:19:59 PM

Quote from: junkman42 on July 31, 2011, 10:05:42 AM
John Ed, the injection of water and methanol into a aircraft recip engine is for a different reason than water injection into a diesel!

My Uncle was a Flight Engineer on a B17 in WWII. He shared that the water injection allowed him to "lean out the mix" to get Max Take-off Power. Seems that those air cooled engines needed to be run rich for cooling reasons and to prevent burning the exhaust valves. Secondly, he could run a lot more spark advance with the water injection turned on and that got him lots more short term power even though it bumped the exhaust gas temp the water kept the engines alive. No spark on the D but exhaust gas temp is still a consideration and lowering it is a good thing.

There is a excellent article in the current issue of Diesel Power Magazine on water methanol injection for diesel engines. I would recommend this magazine for a lot of reasons if for no other reason it gives a person a lot of information on diesel performance which differs in principle in many areas from gas engine operation.

I will purchase a copy of that today....thanks.

If you inject water into the intake of a diesel engine it needs to be downstream of the turbo

Makes sense to me. The outlet of the turbo is pretty hot and you can inject more water and get more cooling without approaching the dew point. Liquid water shouldn't hit the combustion chamber I don't think.

and in My opinion down stream of the blower.

I don't like that cause the water might reach the combustion chamber and you would loose the benefit of the cooling attributed to the evap.

I think water should only be injected into a engine that is at operating temperature and terminated before shut down to preclude the possibility of a puddle forming that could be ingested.

Absolutely! Mine only comes on when I am on a pull. It is controlled by a vacuum sensor and I turn the system on and off.

I would also wonder what effect water injection would have on lube oil in areas such as acid formation!John L

Acid formation should be a big consideration unless the engine is brought to op tem p every time it is started. "Wet air" such as in found in the south and east increases the acid due to the oil getting more water blow-by from the combustion AND the engines not getting up to op temp prior to shutdown. Doesn't apply to OTR trucks and our buses as there is no short op cycle. Getting an oil analysis at change time should help you decide on the proper change interval to prevent running oil with exhausted acid neutralization additives. Actual, wherever you live and what the humidity conditions might be. From my pedestrian logic standpoint, I think acid associated with water injection should be a consideration. I would start with the advice of the system vender and then verify that with oil analysis. More frequent oil changes would be the solution....me thinks.

Thanks for the info,

John