enginehistory.org

[jjuutinen]

Folks, I have "coerced" to write a short article on engines and fuels used in the Bf 109. First, I will argue that German engines did not fully exploit the good rich mixture response of their fuels, especially C3. I base my argument on the fact that the difference between minimum sfc and sfc at emergency power is no more than 20% (in case of the DB 605A it is 200 g/hp/hr vs. 240 g/hp/hr), i.e. vastly lower difference than in Allied engines.

Second, wasn´t it so that a PN 130 allowed 30% higher IMEP, not BMEP to be had?

Jukka

[rinkol]

I think I saw a comment in Heron's book that tests on captured DB engines showed that increasing the mixture richness did not improve power output (this seems to have been an implied criticism of fuel injection in that the possible cooling of the mixture was not obtained). I do recall that on some of the BMW 801 engines, there were provisions for spraying 96 octane fuel into the supercharger impeller and increasing the boost (about 10% power increase).

Robert Inkol

[szielinski]

try http://www.fischer-tropsch.org/primary_documents/gvt_reports/BIOS/1612/bios1612_toc.htm
I suggest sections 1 & 2 would be of interest following on from Rob's comments.

[szielinski]

I also have an article on anti-knock tests the Germans carried out. E-mail me and I'll send them to you (It is from the same site, but may take a while to find).

[jjuutinen]

Thanks for the links! I have read some reports on that site, but I have missed this one. Though I could not still find the reason why didn´t the detonation limit improve with rich mixture in the DB srs.

It was also mentioned how the formation of droplets affected knock behaviour at various charge temperatures. It seems that perhaps improved nozzle design and increased injection pressure would have allowed lower charge temperatures to be exploited thru better atomization of fuel. Comments?

Jukka