A beautiful Me109 pump

[schwarze-man]

This is probably a DB605 fuel injection pump with the control unit EPHB 52/14. I should be able to confirm later. The DB601E is listed with the 52/7.
For information, the pump is an alluminium bodied 12 element variable output rack-type pump. The mixture control is not linked directly to the Pilots throttle control, it functions through the sensing of: manifold pressure, ambient pressure, manifold air temperature. Of course, the pump is mechanically linked to the engine by the geared drive. This type of pump also incorporated a weak mixture idle bias and the "schnellstopp" delivery cut-off for engine shutdown.
Cheers

SM

[Broncazonk]

Originally Posted by schwarze-man

This is probably a DB605 fuel injection pump with the control unit EPHB 52/14. I should be able to confirm later. The DB601E is listed with the 52/7.
For information, the pump is an alluminium bodied 12 element variable output rack-type pump. The mixture control is not linked directly to the Pilots throttle control, it functions through the sensing of: manifold pressure, ambient pressure, manifold air temperature. Of course, the pump is mechanically linked to the engine by the geared drive. This type of pump also incorporated a weak mixture idle bias and the "schnellstopp" delivery cut-off for engine shutdown.
CheersSM

Awesome information!

Question: If the throttle was upstream from this unit, how did they prevent cavitation in the fuel line between the throttle and the pump when the throttle was moved aggressively?

Bronc

[schwarze-man]

Yes, the mixture control EP/HB 52/14 is listed for the early DB605A-B and the complete pump shown should have the makers code PZ12 HP110/25 although this is not shown, it will be stamped on the top face at the end and, usually on a plate on the side. The complete unit would also have had the de-aerator FP/LQ 300/3 fitted but this appears to be missing.
Bronc, the DB605 fuel injection system operates independently of the throttle. The throttle just regulates air delivery to the inlet manifolds and so, to the inlet valves etc. The fuel injection pump reacts to manifold air pressure, ambient air pressure and manifold air temperature to vary the fuel delivery to match the air quantity being admitted by the throttle. The throttle position is not sensed or used by the fuel injection pump, apart from the weak-mix idle bias with the throttle in the idling range. The PZ12 HP type pumps are fast acting to respond to throttle movement via the corresponding pressure changes in the inlet manifold. The response is exceptional for such a large engine.
Anyone interested in these engines can purchase the original manuals from several specialists. Archiv Hafner is one good source for copy of the original DB605A manual. Well, until I write my book on the subject!

SM

[schwarze-man]

Going forward on the subject of fuel feed and cavitation, the DB605 has a fuel backing pump that you can see in the diagram posted as Clipboard 1, called the Kraftstoff Vorderpumpe. This pump is driven by the engine and has two spur gear elements working in parallel. The pump is always turning and pumping when the engine turns and its output exceeds the injection rate. The spare fuel that it pumps is internally recycled in the pump by the pressure regulating membrane and its spill valve. This pump maintains a pressure in the delivery line to the injection pump of 1.3 to 1.8 kg/cm2. As the main fuel injection pump varies its rate of admittance of fuel to inject according to engine demand, the backing pump varies the amount of fuel it internally recycles, with a very slight change of pressure and virtually instant increase or decrease of flow rate to meet demand of the injection pump.
Cheers

SM

[Broncazonk]

Originally Posted by schwarze-man

Going forward on the subject of fuel feed and cavitation, the DB605 has a fuel backing pump that you can see in the diagram posted as Clipboard 1, called the Kraftstoff Vorderpumpe. This pump is driven by the engine and has two spur gear elements working in parallel. The pump is always turning and pumping when the engine turns and its output exceeds the injection rate. The spare fuel that it pumps is internally recycled in the pump by the pressure regulating membrane and its spill valve. This pump maintains a pressure in the delivery line to the injection pump of 1.3 to 1.8 kg/cm2. As the main fuel injection pump varies its rate of admittance of fuel to inject according to engine demand, the backing pump varies the amount of fuel it internally recycles, with a very slight change of pressure and virtually instant increase or decrease of flow rate to meet demand of the injection pump.
CheersSM

What an OUTSTANDING post. Absolutely Superb. Just SUPER.

Thank you for the time it took to post this.

Bronc

[Broncazonk]

Originally Posted by schwarze-man

Bronc, the DB605 fuel injection system operates independently of the throttle. The throttle just regulates air delivery to the inlet manifolds and so, to the inlet valves etc. The fuel injection pump reacts to manifold air pressure, ambient air pressure and manifold air temperature to vary the fuel delivery to match the air quantity being admitted by the throttle. The throttle position is not sensed or used by the fuel injection pump, apart from the weak-mix idle bias with the throttle in the idling range. The PZ12 HP type pumps are fast acting to respond to throttle movement via the corresponding pressure changes in the inlet manifold. The response is exceptional for such a large engine.
Anyone interested in these engines can purchase the original manuals from several specialists. Archiv Hafner is one good source for copy of the original DB605A manual. Well, until I write my book on the subject! SM

What an amazing design and piece of engine engineering. Wow-o-Wow.

Write the book, I'll buy it for darn certain.

Bronc

[Broncazonk]

The complexity of the engineering boggles the mind.

Could the pilot manually adjust the lean/rich fuel mixture independent of this system?

Also, the supercharger would have dramatically changed the density altitude of the air going into the intake manifold vs. ambient, and then add 1.4 atm or more of boost!

The complexity...

Bronc

[Tony Kambic]

SM, From your description, are you saying there is not a fuel-boost pump for this engine?

Tony

[schwarze-man]

Originally Posted by Broncazonk

What an amazing design and piece of engine engineering. Wow-o-Wow.

Write the book, I'll buy it for darn certain.

Bronc

Thanks Broc. I already offered a project to Schiffer publishing a few years ago to produce a full technical description of the DB605 in German and English but, they did not respond.

SM

[schwarze-man]

Hi Bronc,
The DB605 had no mixture control for the pilot. The response of the mechanical mixture control unit on the fuel injection pump provided the range of fuel flows and fast response to match the throttle movement and engine demands accurately. As I posted, it does this through sensing just, Manifold pressure after the throttle valve, ambient air pressure and Manifold air temperature. The mechanical geared drive provides the power and the timing coordination for the injection sequence.

SM