Adjusting Compression using WI

[Obscene_CNN]

I'm looking for a paper on using water injection to adjust the effective compression ratio of an engine. The concept was to inject enough water to raise the compression ratio of the engine to the maximum that the fuel mixture would allow before knock would set in. I thought that this was a NACA paper but I am unable to find it.

Anybody know where I can find it?

[JohnA]

.. The concept was to inject enough water to raise the compression ratio of the engine to the maximum that the fuel mixture would allow before knock would set in...
I don't think that you'll find such a paper. Water is not injected in order to raise the CR.
It is used so that the engine can *cope* with the CR that has been raised for some reason (such as running higher boost pressure on a stock engine)

[Obscene_CNN]

I know such a paper exists. I had it before my hard drive crashed.

Water injection can be used to raise the compresion ratio. You just need to use enough water , control the amount tightly, and make sure all the water is expelled from the cylinder for the next cycle. After doing a more vigorous search I remembered it wasn't a NACA report. I think it was British and pre WWII(It could have been durring or just after). Since octane rating can and does vary from batch to batch, the purpose was to tune the compression ratio to run at the maximum the fuel would allow. The research paper used an actual aircraft engine to test it. It was a normally aspirated opposed four cylinder engine as I remeber it. I can't rember the percentage increace in power output they gained which is what I want to know.

It took water injection to the next level.

[JohnA]

I've got several WI papers linked from the Water Injection pages of my site (with local copies as well)
Never seen this one though, and I'd be interested to read it if you happen to find it. :D

[hotrod]

That does not sound like any NACA study I am aware of either, and I've scanned through a large number of them that had to do with ADI.

Let us know if you find it, or can remember a unique term used in the paper that might help with a google search.

Larry

[Obscene_CNN]

I'm pretty certain now it wasn't NACA. It was british, mabey a R.A.E. paper. It might have been a paper by Harry Ricardo but I have about googled out all possibilities of that. I'm pretty sure the website I found it on is no longer up as I would have run across it with my water injection searches. I'm still looking an will keep you all posted.

I know it exists!