RHR Doseur / Throttle operation

[EDC5]

Yes, in theory the ecu could control the valve to hold it partially open against the return spring, but only if there was a feedback mechanism of some kind to provide a servo loop. Without this the system is not capable of securely and confidently adjusting to any particular position other than fully open or closed as EDC observed. The vnt turbo uses a similar or identical valve and has a feedback device which allows the ecu to adjust the vanes to any required position, which is a different control.

Everything I'm writing here is based on the RHZ & RHY engines.
The air doseur's official name in the technical documentation is the EGR throttle butterfly. It's there to assist the EGR operation. It can be opened to any position between fully open & fully closed, it does this with calculated values from the ECU & doesn't need any feedback sensor. On these engines the EGR valve & turbo wastegate (RHZ only) Also work exactly the same, they are vaccum operated against a spring return, they can be opened to any position & neither have a direct feedback sensor either.

All the evidence points to the single unit choking airflow when the key is turned off, and nothing else.

You can actually watch the valve operating when the engine is idling if you take the air pipe off.

Ok, so I bought a spare doeseur from ebay and connected the vacuum hose to it in place of my own one, I got someone to watch it as I revved the car from idle and it didn’t do anything, only when I turned the engine off did it flap closed for about 5 seconds before opening again.

I'm not saying that it doesn't do anything to help the EGR but maybe the EGR wasn't operating when I was testing it. I might repeat the test with a warm engine or something.

I'm really quite interested in this unit and would like to like to know more.

[wheeler]

If the engine was cold its likely the EGR was not operating at the time.

[xf1ref]

This doseur is also at RHH engine 163hp. I noticed that after a long road and after I stop the engine this doseur is making a pumping noise, like is opened and closed for 5 times. I tested with lexia and the doseur stopped the engine...the test was successful.
This kind of doseur I saw is also used on ESP system at VAG PD engines. With the ESP activated and when the wheels slip on ice/snow, the doseur limits the engine rev. and it feels like the engine has no power.

[EDC5]

This doseur is also at RHH engine 163hp. I noticed that after a long road and after I stop the engine this doseur is making a pumping noise, like is opened and closed for 5 times. I tested with lexia and the doseur stopped the engine...the test was successful.
This kind of doseur I saw is also used on ESP system at VAG PD engines. With the ESP activated and when the wheels slip on ice/snow, the doseur limits the engine rev. and it feels like the engine has no power.

That's interesting.
I hear the EGR valve doing this sometimes when the engine is turned off as it calibrates the endstops, so does the VNT turbo for that matter so I suspect that the doseur also needs calibrating. Maybe they take turns using whats left of the vacuum reserve to calibrate once the engine has been turned off.

[tmead]

As part of a recent repair I took the inlet off mine and looked at the air doseur again. The 307 2.0 hdi has the dual flap one. The same vacuum flap was pretty well worn out as before. (cant remember which one) The vacuum diaphragm unit pulls on a rack which turns the pinion on the shaft. The rack in the recent one (s/h unit fitted about 3 years ago) is well worn, to the extent that it jams in the pinion teeth. The previous one was so worn it allowed the pinion to float around to wherever it liked !
I've grabbed bits out of the good vac flap on the old one (see theres a reason for keeping old bits that get taken off) which looks almost untouched and replaced the rack in the one on the car. The guts are nearly the same, even though one operates to spring closed and one to spring open. the springs are colour coded, so make sure you get the right one ! the plastic diaphragm housing clips apart, and there's a spring clip that holds the butterfly shaft in place. I'll bet there's a bunch of cars with the dual unit driving round with one of them either stuck or flapping around wrongly.

[EDC5]

Just as an update to this thread, stumbling across this diagram Marc posted about the fuel / air system on the Siemens operated DW10B the Doseur is called the "Throttle Butterfly Housing (EGR)". Therefore I can conclude that the Air Doseur is indeed used to assist the EGR system.

Diagram here, Siemens system, note points 1 and 21:

C5-MK-II-Masood-A.png	C5 MK II Masood B.PNG
Air circulation (as per arrows):	Legend

Similarly for the Delphi injection system, point 12:

EGR Circuit C5 X7 DW10BTED4 FAP with Delphi 3.4 Injection

X7 DW10BTED4 EGR Circuit.PNG

X7 DW10BTED4 EGR Table.PNG