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Re: More efficient alternative to a 2.1i engine?
Posted: 04 Nov 2015, 14:28
by marlinowner
What is liquid liquified petroleum gas and in what way is lpg "super cold"? It's stored at ambient temperature.
Admittedly it does turn into cold propane (mostly) when it vaporises.
Re: More efficient alternative to a 2.1i engine?
Posted: 04 Nov 2015, 18:32
by silverbullet
Adiabatic cooling
Re: More efficient alternative to a 2.1i engine?
Posted: 04 Nov 2015, 18:49
by marlinowner
That would be Joule-Thomson effect? Used to work with cryostats that used compressed N2 and Joule-Thomson expansion to get close to 77K. I was thinking that with lpg it was the phase change from liquid to gas ie heat of vaporisation.
Re: More efficient alternative to a 2.1i engine?
Posted: 04 Nov 2015, 19:34
by silverbullet
Search me, I only scraped an E at Physics A level!
I have merely heard that the latest liquid gas injection systems help to increase inlet charge density by explioting the drop in temperature through vapourisation.
Re: More efficient alternative to a 2.1i engine?
Posted: 05 Nov 2015, 03:51
by heretic
guess the vast % of cooling would be from phase change plus a little from cooler base liquid temp.
I know stuff all re the liquid injection but if its early enough in the inlet to cool the air charge as well then expected results from charge density would follow?
Normal vapour mix is no gain as it is already expanded and close to ambient air temps[in aus anyway:)].
much of the discussion on KC is musings but thought an actual case study was relevant.
My thoughts on the rebuilt engine are that the blueprinting and cam would also be a significant % of the power gain as would be expected.