NACA high-speed compression-ignition engine - General - VWDiesel.net The IDI, TDI, and mTDI source.

NACA high-speed compression-ignition engine by VWRacer on 31 Mar, 2005 14:58
One of my brothers is also a diesel fan, and passed along this link to a 1930 multi-fuel diesel project run by NACA.

http://naca.central.cranfield.ac.uk/report.php?NID=816

The original reports are replicated on the NACA-US and NACA-UK websites, and is downloadable as a .pdf (1.4mb) from the UK at:

http://naca.central.cranfield.ac.uk/reports/1930/naca-tn-344.pdf
#1 by Northern RD on 31 Mar, 2005 15:32
Wish they`d gave some detail on injector design, it reminds me of what Orbital(the 2-stroke people in Austalia) were doing were trying to do before they went digital,...
#2 by fspGTD on 31 Mar, 2005 15:41
Wow - very cool. Thanks for the link!
#3 by lord_verminaard on 31 Mar, 2005 16:23
Very interesting combustion chamber design. Although a bit limited- just imagine what a cylinder head using that design would look like for a 4-cylinder engine!!

And 13.6:1 compression? How in the world did they even get the thing to start? :shock:

Brendan
84 Scirocco 8v
00 Camaro L36 M49
#4 by VWRacer on 31 Mar, 2005 16:27
With glow-plugs, I have see lab diesels start rather easily at 12:1.
#5 by fspGTD on 01 Apr, 2005 07:21
In this NACA experimental engine, direct injection design with no pre-chamber = less combustion chamber surface area = less heat lost to cooling system = not as much compression ratio required as our IDI VW diesels.

Another example of this is the TDI diesel, also has lower compression ratio (below 20:1 vs our IDI diesel's 23:1) and better thermal efficiency as a result of less combustion chamber surface area.

PS - it is interesting to note that both the VW IDI and TDI designs move the air to the fuel, while this NACA experimental design has relatively stagnant air. At the time of this report it seems they hadn't really figured out how to make the air move. Very interesting experiments, nonetheless!