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The history of Kugelfischer fuel injection

The history of Kugelfischer fuel injection

There's a great article on the genesis of the pump over at the tii register (1). I wanted to expand upon that with some of the early history to understand how the pump came about. Over the years, the pumps were branded with different names: Deckel, Schaefer, Kugelfischer & Bosch - it seems most of those companies were based in Bavaria, around Munich...but what started the ball rolling? Here I trace the history of technology and design and try to build the jigsaw of these different companies and locations that have kept this technology alive for 70+ years. The longevity of the pump is due to its precision, ruggedness, and simplicity... compared to other MFI systems, its fuel map is more precise/larger, and it is a much simpler design with far fewer moving parts than other Spica/Bosch pumps - and that simplicity also made it lower cost than the MFI competition.


Friedrich Deckel GmbH

Founded in 1903 as Bruns & Deckel, this was a precision engineering company where Bruns was the inventor/designer and Deckel was the engineering wizard capable of translating these designs into innovative products. They focused on shutters for photographic equipment: Bruns had invented/patented a 'leaf shutter' with a mechanical mechanism to control the shutter speed - enabling accurate fast & slow shutter speeds. Their brand name was 'Compur' a contraction of Compound Shutter and Uhrwerk (clockwork). These shutter mechanisms were embedded in the lenses Carl Zeiss and many other European manufacturers produced (2).


Carl Zeiss Compur Lense


Deckel made the equipment to manufacture the Compur shutters since no suitable precision equipment was available, and as time went by, the equipment side of the F.Deckel company became more important. The company became well-known in the precision engineering equipment business in the late 20th century. One area of the equipment business was machines to enable the precision manufacture of ball bearings.


In 1928 the German Reich Aviation Ministry set out a specification for future aero engines that required all new engines to feature fuel injection (3). In the 1930s, BMW had licensed the Pratt & Witney Hornet radial engine (4) and developed the 801, 42 Litre 14 Cylinder radial engine to meet that specification.


I speculate that BMW approached the local Munich precision engineering company, Deckel, to develop the mechanical injection system.


Deckel developed an "Axial Fuel Injection Pump" which featured a fixed-stroke pump piston for each cylinder, driven by some 'cam ring.' The fuelling was varied by the careful rotation of the barrel for each piston: there was a spiral groove from the crown down the skirt of each piston and a 'spill port' in the wall of the barrel, so by rotating the barrel to align with the spiral groove, the compressed fuel will be bled off until the piston/groove rises to shut off the spill port. In this manner, the injection quantity can be varied down from the full stroke fuelling. Simple in principle but a precision device ideally suited to Deckel's skills.




During WW2, the focus of the Freidrich Deckel company shifted strongly towards manufacturing these pumps, with the camera shutter manufacturing space converted to make injection pumps. The factory was bombed in 1943 and completely destroyed, but by that time, Germany had decentralized production of critical equipment and production restarted in various locations.


FAG Friedrich Fischer

Friedrich Fischer opened his first bicycle-making business in 1872 in Schweinfurt and started manufacturing ball bearings in 1883. By then, he was already known as 'Ball Fischer' (Ball=Kugel), and business expanded fast. In 1897, Erste Automatische Gußstahlkugel-Fabrik, vorm. Friedrich Fischer AG (FAG) was formed [Guss Stahl Kugel = Cast Steel Ball].


Kugelfabrik Fischer


The name 'Kugelfischer' was used as the company telegram address in this period. Unfortunately, Friedrich died in 1899, and the business started to go into decline. (6)


Georg Schäfer & Cie 

Formed in 1904, Schaefer was another Schweinfurt-based ball bearing manufacturer. Through family connections, Georg Schaefer had a minority stake in FAG (see his name as a director in the pic above), and in 1909 able to purchase FAG, he kept the better-known FAG name. He embarked upon a rapid expansion of the business thru WW1 and into the challenging depression years. Georg's son, Georg Shaefer Jr, became executive director in the mid 1920s. In 1941, after various management changes, the company was renamed Kugelfischer Georg Schäfer & Co. The Ball Bearing factories were the target of the famous Schweinfurt Raids in 1943, and 85% of the Schaefer's factories were destroyed (7).


The rebuilt FAG Kugelfischer Georg Schäfer KGaA offices in Schweinfurt, 1963 (8)


Schäfer Einspritztechnik 

This is the point where Deckel and Kugelfischer come together - I cannot find any specific articles on this transition, but it would appear that Deckel collaborated with Schaefer in the area of the fuel injection business, and Georg Schaefer formed what we would call today a 'special purpose vehicle' based in Munich to eventually take-over the business - this was Schaefer Einspritztechnik (Schaefer Injection Technology), it seems this happened in the early 1950s.

I speculate that Schaefer knew the F Deckel company through being a customer for Deckel's ball-bearing grinding equipment

We can see the pump 'branding as "FRIEDR.DECKEL," "SCHAFER-PUMPE," and "KUGELFISCHER SCHAFER-PUMPE" on pumps made in the 1960s and early 1970s - so there was some transition of ownership:




Deckel had developed a variable stroke fuel injection system that was far less complex than the 1930s fixed stroke aero injection systems.


To quote from a 1965 article by dr. Jenő Bujtor in Autó-Motor, titled "Simplification of petrol injection equipment":

"Experience gained with gasoline injection devices put on the market in recent years showed that they are undoubtedly beneficial in terms of increasing performance and reducing specific fuel consumption, but their wider spread is strongly hindered by their complicated and delicate structure. Significant progress in this field was brought about by the Kugelfischer system injection equipment, ....... This extremely ingenious device is much simpler than the gasoline injection systems known so far."


Deckel/Schaefer started collaborating with Peugeot in 1956 - leading to the launch of the Fuel Injected Peugeot 404 in 1962 (9). Most likely, there was a collaboration with BMW as well, they were both based in Munich, but the earliest references to BMW's use of the pump are the late 60's factory racers.


Robert Bosch GmbH

Bosch had been developing mechanical fuel injection for aero applications triggered by the same government specification mentioned above, providing the injection systems for the Daimler-Benz DB 600 series of V12 aero engines.


Bosch Mechanical Injection System


After WW2, Bosch sought new applications for this Mechanical Fuel Injection technology, and in 1954 the first successful implementation of petrol fuel injection was by Bosch & Mercedes in the Mercedes-Benz 300 SL gullwing (10). This MFI remained a niche business on premium engines for Bosch, likely because of the complexity & cost of its MFI pumps.


In the 1960s Bosch licensed Bendix Corporation's Intellectual Property for the Electrojector system (itself developed from military aero engine tech, 11). This was the first electronically controlled fuel injection system that Bosch developed into the D-Jetronic system that was launched in 1967. A wide variety of EFI systems have been developed since then. The big push to switch to EFI came from tightening emissions and fuel economy demands, which only computer-controlled systems could achieve.


It seems surprising that Bosch purchased the mechanical fuel injection business from Schäfer Einspritztechnik GmbH in 1979, some 10+ years after they launched Bosch's EFI. At least part of the reason appears to be that the Kugelfischer system offered extreme reliability, as required for BMW's 1350 hp Formula 1 Turbocharged engine (M12/13). Bosch had both the Motronic EFI and the MFI systems, and for many of the early races in 1982, BMW chose the MFI system (12). These F1 systems use servo motor control of the cone in the Kugelfischer pump, so the injection volume is electronically programmed (the servo motor twists the cone to the right position). Still, the fuel delivery and injection are done mechanically, the same as Friedrich Deckel had designed in the 1950s.

 Bosch Fuel Injection Pump Label

Bosch Tag


BMW M12 Servo-controlled MFI pump

Koller & Schwemmer

Koller + Schwemmer GmbH & Co was a Bosch service agent in Nuremburg from the 1930s, in 1989 Bosch transferred all the mechanical fuel injection system support responsibilities to Koller and they provided service and support to the legacy systems in the field. In 2012 the Bosch Automotive Aftermarket division purchased Koller & Schwemmer and it now operates in cooperation with the Bosch classic division to supply parts & service to mostly diesel but also the petrol MFI (incl Kugelfischer) systems (13).


The Pump

Here's a video I made to show how the BMW2002tii pump works:




  • Peugeot 404 (1962), Peugeot 504 (1968)
  • Lancia Flavia 1800 (1965)
  • BMW : 2000 tii (1969), 2002 tii (1971), 2002 turbo (1974), 520i (1972–1976) , M1 (1978)
  • Ford Capri RS 2600 (1970)
  • Porsche 911 RS & RSR, Porsche 911 SC/RS
  • Ferrari 308 Group IV Rally car


Although awful quality, this video by BMW NA provides a nice pump overview:


(1) https://www.2002tii.org/kugelfisher-pump-overview/

(2) https://web.archive.org/web/20130926091308/http://www.kl-riess.dk/compur.eng.html 

(3) https://www.youtube.com/watch?v=DOSe4lmy8S4

(4) https://en.wikipedia.org/wiki/BMW_132 

(5) https://www.henn.com/en/project/friedrich-deckel-maschinenfabrik

(6) https://www.encyclopedia.com/books/politics-and-business-magazines/fag-kugelfischer-georg-schafer-ag

(7) https://en.wikipedia.org/wiki/Second_Schweinfurt_raid

(8) https://www.schweinfurtfuehrer.de/industriegeschichte/ära-haus-schäfer/organisation/

(9) https://autotechnika.hu/cikkek/motor-eroatvitel/8606/kugelfischer-schaefer-benzinbefecskendezes

(10) https://www.bosch.com/stories/bosch-brings-gasoline-injection-to-cars/ 

(11) https://www.roadandtrack.com/car-culture/a36769816/brilliant-doomed-pioneer-fuel-injection/

(12) https://www.motorsportmagazine.com/archive/article/november-2009/40/bmw-formula-1/

(13) https://www.autohaus.de/nachrichten/autohersteller/uebernahme-bosch-kauft-koller-schwemmer-2744516




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Thanks dlacey! thats as good as buying a book. I have an ancient Deckel Maho machining center and its freakin amazing how brilliant the engineers were back in the day



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I added an additional pic of the BMW M12 turbo setup with the ECU/servo- controlled Kugelfischer pump. Thanks to @CG901 for the permission to reuse that shot of his engine!

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Here's some pics from eBay Kleinanziegen (German Classifieds site) of a 1984 vintage BMW 320 Group 5  pump. It appears to have two electrical connections, at least one is a servo motor to control cone position. Another primitive ECU-controlled Kugelfischer pump:






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@2002GT3CAR shared some pics with me of his early Motorsport/race pump, you can see the operation principle is the same as the pump in the video above, but the implementation is different.  The hinged plate is cast alloy rather than pressed steel, the pump body has more internal structure to support the tappets, and the head assembly is a sleeved alloy piece similar in general to the mid-60s Lancia/Peugeot examples. Thanks Edward for this interesting addition to the story.

image.png.f88fc02e28f51fb9f07208cf868779bc.png  image.png.8bba885434e7b00a6020f85e9df7ff82.png



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