big oops found tonight

[Gary - K7GLD]

Went directly past "broke in" to "broke" :-laf

SORTA like passing "GO", and not collecting the $200... :-laf :-laf

 

[Forrest Nearing]

Water adds oxygen to the combution mix as it breaks down.

well, it really just adds water to the combustion mix... and turns to steam... if you were "breaking down" water and getting oxygen out of it, you'd be left over with hydrogen which is highly flamable!



the theory is that it adds power by increasing compression ratio but it also soaks heat out of the chamber as it takes energy (heat) to convert it to steam)

 

[WCounts]

Water does cool

It took 250*f off his egts but he may have turned it on too late. Too much water will quinch the combustion.

I wonder if water really does cool down the chamber,, I have two anecdotes that question that:



1)Years ago when I was in High School I had a 40 DeSoto fixed up with water injection. without water it would go 85 WOT. Turn the water on it would go 100. Turn the water off it would then slow down to 85 again.



Took the engine apart after some time cause it was using lots of oil and found all the pistons with the top corners burned off.



2)Friend of mine was a B17 Pilot in WWII. He told about turning the water on those big radials when taking off. He would get tears in his eyes as he explained those cylinders would "swell" with all that additional power.



But,,, he said you could only run water for a short time cause it was hard on the engine.



Now with both these examples,, how come we always think it cools the chambers down to run water. I don't get it. Hopefully someone can splainit.

 

[RobertP]

Water does cool

It took 250*f off his egts but he may have turned it on too late. Too much water will quinch the combustion.

wow billy looks like you really doing good droping your E. T's looks like . 8 tenths from this time last year( give or take a few months) good luck this race season.

 

[WCounts]

With the racing season over with I've been trying different set ups. The Smarty made a big differance but it takes time to get everything working together. I have been working with water injection lately with good results. Really cools things down.

 

[cerberusiam]

if you were "breaking down" water and getting oxygen out of it, you'd be left over with hydrogen which is highly flamable!

Now your on the right track.





Water chemically transforms at about 2000 C. In cyclinder temps are around 2500 C in a diesel engine. We now have Hydrogen to add back the energy lost converting the water to base elements plus free oxygen to cool the burn down. Net result is lower EGT's and the same or possibly more power.

 

[BGott]

The sole purpose, in a gasoline engine, anyway, for water injection is to control detonation. I imagine that water injection in a diesel engine would lower EGTs.

 

[bzingre]

Water adds oxygen to the combution mix as it breaks down. This creates a denser charge which promotes more complete combustion at a lower temperature. As a side effect you also lower emissions and allow the ability to add more injection timing.



Water injecton into the intake stream is not as efficient as direct injection and can lead to some issues. It is usually injected thru a small orfice so the amount is not going to intefere with the compression process and cause a hydro lock but too much water in the wrong spot can lead to other issues. Here is a pretty good read on the benefits and possible problems.



http://homepages.cae.wisc.edu/~rutland/research.dir/NOx_water/2000-01-2938.pdf

Water doesn't break down in the cylinder!!!! If that was the case, every engine on earth would run on it!!! Water cools and increases compression (not compressible). Heat transfer to the water/steam is much greater/faster than to air... keeps the cylinder from absorbing the heat too.

 

[Spooled-up]

Wouldn't adding water to the cylinder also increase the compression ratio of the engine? I would think that since fluids aren't compressible, the water would displace some of the cylinder volume and increase the compression ratio. This equates to more pressure in the cylinder and more power, but obviously puts more stress on the rings and other associated parts sometimes leading to damage like in the engine in the first post.



Someone tell me if I'm missing something, but that's what seems would be happening in there.

 

[jwilliams3]

The damage in the pictures is all from heat PERIOD...



I have seen that too many times with a Common Rail engine.

 

[Yo Hoot]

The damage in the pictures is all from heat PERIOD...



I have seen that too many times with a Common Rail engine.

Probably because it's so easy to just "turn it up" without covering the bases.

 

[cerberusiam]

Water doesn't break down in the cylinder!!!! If that was the case, every engine on earth would run on it!!! Water cools and increases compression (not compressible). Heat transfer to the water/steam is much greater/faster than to air... keeps the cylinder from absorbing the heat too.

First off, lookup Thermolysis and how it pertains to breaking water down to get the hygrogen (highly flammable) out. After you get done with that, research the temps and pressure in a diesel engine under load, the vapor curve of water, then get back to me.





Second, compression, or compression ratio as they are essentially the same thing, is the relationship of volume of a cylinder with piston at BDC to the same cylinder at TDC. It is a mechanical factor based on the construction of the engine. YOU CANNOT CHANGE COMPRESSION BY INJECTING WATER!!!



The ONLY thing injecting water does is change the density of the air charge. Change the density of the air charge changes combustion temps. IF your water injection is working correctly the combustion flame can actually burn hotter with less overall EGT's.



Water injected in a fine stream into a 300 degree plus air charge then compressed at 17 to 1 is NOT going to be liquid at at a pre-injection temp 700 C. It will be vapor which is compressible and once again all it is doing is changing the density of the air charge. The denser the charge the more heat that is needed to raise the temp.



From just the pretty pictures that were posted there is no way to know for sure what happened. The 1500 degree temp is not too much if it is for a short time in the combustion cycle, but, advance the timing too much and the 1500 is too much. The only thing that is a given is it was TOO HOT for TOO LONG and spraying water on it did not help.

 

[Yo Hoot]

How come you bend a rod when liquid enters the cylinder? I always thought that since liquids don't "compress" as much as gasses your compression goes through the roof. With that said, doesn't water spray do the same on a smaller scale?



Sorry I re-read your post. So it is vaporized and compressable.

 

[Bandit1]

that comes from to much water, hence being hydrolocked. with to much water in the cylinder or cylinder temps being to low to completely burn all the fuel and when a liquid is introduced into a small given space (ie cylinder) and it has no place to go bendage occurs. something has to give. the water needs to be a mist to be the most affective in this situation that wasnt the exact setup. like lloyd said big opps, we will know more soon. josh

 

[JasonCzerak]

Boost is a dynamic compression is it not?



Not sure of the numbers off hand but for argument sake:



Motor at 17:1 compression + 30psi of boost would make as much power as a N/A motor at 50:1 compression.



So, if water takes up volume, then dynamic compression occurs. But then again, your seem right about the water vapor. But then again how the heck to bent rods come into play (mainly gassers with Water injection).

 

[cojhl2]

The ONLY thing injecting water does is change the density of the air charge. Change the density of the air charge changes combustion temps. IF your water injection is working correctly the combustion flame can actually burn hotter with less overall EGT's.

This leads one to believe it is better to inject water ouside the cylinder before it gets past a closed valve but after it is heated by the intake compressor.



If it is injected directly to the cylinder the decision as to how much air (Oxy) has been drawn in and hence avail for compression has already been made.



??

 

[cerberusiam]

Boost is a dynamic compression is it not?



Not sure of the numbers off hand but for argument sake:



Motor at 17:1 compression + 30psi of boost would make as much power as a N/A motor at 50:1 compression.



So, if water takes up volume, then dynamic compression occurs. But then again, your seem right about the water vapor. But then again how the heck to bent rods come into play (mainly gassers with Water injection).

Hydro lock occurs from incomplete combustion and/or too much liquid. How is too much liquid present? Too much injected for the combustion event to utilize or and incomplete combustion event failing to convert the liquid. Also, it could be alcohol or other fuel that cause the lock.



A top fuel motor is a perfect example of this. IF everything works right and the fuel burns the motor is happy. Drop a cylinder and it doesn't take long for it to expire, quite frequently in a spectacular manner. As long as the combustion event can convert the fluid be it water or fuel there is no problem.



Water injection in a gasser is dicey because the combustion temps are not high enough to completely get rid of the water. With gasoline water is used to retard the flash over point of the fuel so you don't get multiple combustion events. Since the spark plug provides the trigger for combustion if it doesn't work correct every time and the fuel does not burn correctly every time there can be disatrous results. It not as critical in a diesel as the temps are quite a bit higher and the environment provides the trigger to combust. You can still have the a problem if the combustion event fails and neither the fuel or water burns but it is not as common.



Water injected into a NA motor is probably not going to be vapor at combustion time as the squeeze is not enough to generate the heat needed to convert it at those pressures. However, in a diesel we have boost and a lot higher compression ratio to generate the needed heat to convert it to vapor. As near as I can tell the temps at injection in a diesel are around 700 C at about . 5 MPa. The vapor curve for water at . 5 MPa is about 150 C. The conversion to vapor is done by the mechanical compression so what we are left with is a much denser and wetter air charge.



Hey, I am relatively open minded so if somebody can contribute a clarification, contradictory or not, I am all ears. Please, no more comments about engines running on water and violating the basic physics of things. :-laf Every point I have made is easily verified and is a part of HS chemistry and physics classes. It ain't rocket science. My interpretation may be a bit flawed but not by design. :-laf

 

[Yo Hoot]

The only question that comes to mind is how quickly does the water vaporize? Just like combustion and flame front, these things all take time and need to be factored in.

 

[Vaughn MacKenzie]

The only question that comes to mind is how quickly does the water vaporize? Just like combustion and flame front, these things all take time and need to be factored in.

I would say within microseconds after the cylinder air reaches 212F, and well before the injector starts firing.



Vaughn

 

[cojhl2]

This leads one to believe it is better to inject water ouside the cylinder before it gets past a closed valve but after it is heated by the intake compressor.



If it is injected directly to the cylinder the decision as to how much air (Oxy) has been drawn in and hence avail for compression has already been made.



??

Oops,, should have said combustion,, Question still stands. .