German Fuel codes

[camons]

I wonder if someone can help with production fuel codes in Germany. From what I understand,
there is a VT series, with the following numbers:
VT 702, referring to gasoline from hard coal made with catalysts 5058/6434
and VT 705, with similar references, except a note with a L-Benzin type

There are also mentions to 3 other types
P 1400, Di.1000 and AT 244, which seem to refer to DHD gasoline
and a further reference to ET110, but this seems to refer to diesel or gasoil.

Does anyone can confirm any of these?

[camons]

Just to make things clearer. When I mean fuel codes, I am referring to production types, not to user-related codes.
To be more precise, user-related codes are those employed by the Wehrmacht, of which the main were:
Heer: "Summer" and "Winter" issues for gasoline and diesel;
Kriegsmarine: I am not aware of any, but the above is possible. Note that KM diesel and fuel oil were different from normal ones, in order to prevent vapour lock and increase resistance to very-high-humidity environments (aka sea);
Luftwaffe: 3 types of avgas were used:
A3 for lower performance, non supercharged engines (i.e., trainers and the like) 80-octane (from at least August 44, 76 oct only), normal gasoline with octane raised by mixing with ethyl alcohol. c. Aug 44 corresponded to 8% of production;
B4 89-octane, tetraethyl lead -TEL used, c. 25% aromatics. c. Aug 44 55% of production; and
C3, 95 octane, TEL, 45% aromatics (from at least Aug 44, 35-45% aromatics) c. Aug 44 35% production.
It is also noteworthy that all fuels (gasoline and diesel) were actually created by mixing at the Wirtschaftsforschungsamt-Wifo depots, according to service specifications. Also, RLM octane ratings are given differently from Allies ratings, which specified both lean and rich mixture ratings. So, the Allied functional rating of C3 is 100/130. C3 had slightly poorer characteristics at lean ratings, but was equivalent to, and in some aspects, superior at rich ratings, due to its very high aromatics content. A3 is not normally considered part of avgas production, as it was just a superior blend of normal gasoline.

Producer codes are something else. Gasoline, especially avgas, had a series of designations, the nature of which is rather obscure. Besides general names like Aubi (Automotivbenzin), Flubi (Flugbenzin) and L-Bi (Luftwaffebenzin), there are a series of technical designations, which, I must admit, I do not quite understand. They are:
the VT 300 series, which include at least VT 303, 342, 342, and 345;
the VT 700 series, which include at least VT 702, 705, 708 and 709; and
the ET 100 series, which include the ET 110 and 120 (of the latter, only one mention so far). ET 110, which is a DHD-type of gasoline, has also been referenced to as Di1000 and T52. BTW, sorry about my earlier post, which posited that ET110 referred to diesel. IT is MOST DEFINITELY NOT CORRECT.
The single digits in the VT series seem to refer to the producer, but there does not seem to be a direct relationship (e.g. Luna=1, Pölitz=5, etc). Also, it is possible that they contain reference to the type of catalyst employed, which influenced the characteristics of the fuel (e.g. the catalyst 5058 seems to have given higher yield/lower octane than 6434), but, again, no direct relationship is apparent.
Does anyone know more details about the producer code designations?

[camons]

Just an update:
the VT 700 series refers to aviation gasoline base stock;
the ET 100 series refers to alkylate production (leading to isooctane)
DHD aromatic fuel was normally identified as such

[GregSingh]

According to Technical specification of the Ministry of Aviation:

VT 100 Foreign source aviation fuel made from petroleum
VHT 302 Aircraft engines benzene made from German black coal
VT 702 Internal source aviation fuel made from German brown coal
A3 aviation fuel made from VT 100 or VT 702 with ethyl alcohol added
A4 aviation fuel made from VT 100 or VT 702 with ethyl alcohol added

[camons]

Thanks, that seems to make some sense. There are a couple of questions I would like to ask, though.
a) Can you identify the RLM source? Or is it an Australian document? Is it available on the internet?
b) as regards VT 302, does "benzene" refers to the German "Benzin" ( English=gasoline) or "Benzol" (English=benzene)?
c) As regards types of aviation fuel, there seems to have been at least two ways to raise the octane rating of A3, according to the specs I have seen:
- addition of tetraethyl lead, but in smaller amounts in comparison with B4 and C3;
- addition of ethyl alcohol, with at least one mention of that after August 1944.
d) By ethyl alcohol addition in B4, do you mean DHD gasoline?

[GregSingh]

a) It's a book: Dr.-Ing. habil. Maximilian Marder, Motorkraftstoffe, Berlin, Springer-Verlag 1942
b) Flugmotorenbenzol
c) RLM specs do not have a date, judging by the book's publication date, pre- or early war; they mention Ethyl-Fluid as additive which had 63.3% tetraethyl lead
d) In those early specs difference between A3 and B4 comes to amount of additive only. There is an error in my earlier post, it should be B4 not A4.

Some info can be also found here: Dr.-Ing. Franz Spausta, Treibstoffe für Verbrennungsmotoren, Springer-Verlag Wien GmbH 1939
But it's even earlier book...

[camons]

Thank you. I'll provide links to RLM specs later, in a couple of days.

[camons]

By the way, maybe it was not a mistake. At least around 1936, B4 was known as A4 (Kockel, Geologie und Erdölpolitik 1928-1938, Dissertation 2003, p. 458)