High compression on low octane

[Logic]

You know... I posted the video above as it's David Vizard.
But never watched it.

http://www.youtube.com/watch?v=jextyKc2UN4

David: Old and forgetting place names n stuff but he knows his s***!
'if you've got everything else (water injection included) right...'
"...We ran as much as 45 pounds of boost on 87 octane fuel.."

"...you got a 1 liter engine...with suitable water injection...?... the old 3 cyl chevy..??...a 100mpg vehicle..."
(eek? where's surprised? )

'inject fuel (and water) every 2nd stroke... every other stroke just inject water...'
a steam stroke... the droplet size is an important factor...'

[freebeard]

You know... I posted the video above as it's David Vizard.
But never watched it.

Another person who doesn't follow your reporting?

I've got a Chevy 3-cylinder, but I don't know that I could manage the droplet size.

[Logic]

Originally Posted by freebeard

Another person who doesn't follow your reporting?

I've got a Chevy 3-cylinder, but I don't know that I could manage the droplet size.

Ye... his videos are VERY long winded
I much prefer his books and written articles.`

Yes; he carries on about droplet size and getting the left over (unevaporated) droplet to turn to steam at just the right time.
But not much practical ; How To!

Even Aquamist's forum doesn't seem to have much droplet size info.
https://www.aquamist.co.uk/forum2/vbulletin/

The big Take Away here is that the correct amount of water injection with fuel and spark adjusted for it, allows much higher compression and the fuel savings that come with that.

From there one might play with different nozzles and pressures to try tweak droplet size.

[freebeard]

I thought that was half of it. The remainder being the steam power power stroke.

What do you think are the proportions contributed?

[Logic]

Originally Posted by freebeard

I thought that was half of it. The remainder being the steam power power stroke.

What do you think are the proportions contributed?

The more I think about it, the more I think David passed from the realm of his experience into speculation at this point of his video.

Lets say we suck water mist only into a cold (room temp) engine.
The intake valves close and the compression stroke starts.
The increasing pressure increases the temperature of the mixture, where the heated air heats the water droplets, but it also increases the boiling point of the droplets.
So at what point, if ever, do the water droplets turn to steam?

This is the point at which I think David moves from experience into speculation...

If there's also fuel injected and a power stroke the pressure continues to climb past TDC, due to a dramatic increase in temperature. So at what point in the power stroke do the droplets turn to steam?

Then there's heat in the surrounding combustion chamber being absorbed where pressure would increase the rate of absorption, except there's a decreasing delta T...

Then there's evaporation occurring during this process....

Where (and when) do you want to inject the water?
Different places have different effects. Especially if direct injecting.

So...just how far down this rabbit hole of thermodynamic etc maths do you want to go!?
At some point, after much equation-ing, even the scientists say "Uck Fit! Lets just inject the damn mist (based on educated guesses) and see whatTF happens!?"

https://sci-hub.ru/https://www.scien...96890419300883

Also NB that Boric Acid is synergistic with water injection..!