Question about the AGR system in the ACV/T4 (Sorry)

I don't really want to bother anyone with this tiresome topic, but I couldn't find an answer despite a thorough search.
Status: T4, Year of manufacture: 06/2000, Engine: ACV (75 kW, 5-cylinder TDI), Mileage: 83,000 km, I understand the function of the EGR valve!
Here in the forum, when discussing AGR (Abgasrückführung), people often talk about 'directing charge air into the exhaust system' and 'directing exhaust gases into the intake system,' at least in principle.
In the ACV system, there is a valve in the intake manifold that, via a connecting pipe, directs exhaust gases into the intake manifold. However, there is definitely no connection that would allow intake air to flow into the exhaust system.
Question: So, in the ACV system, are only exhaust gases mixed with the intake air, and is no corresponding amount of fresh air discharged?
Basically, I don't really care, but I just wanted to know.
The image of the AGR valve in the technical article also shows a part that I don't have under my hood. In my case, the exhaust gas is simply directed into the intake manifold via a valve. This likely leads to severe contamination of the intake manifold after the valve. I've temporarily disabled the EGR valve (using the old vacuum hose plug).
A remarkable change in driving behavior, however, could not be observed.
However, the smoke cloud during partial to full load changes is not quite as bad anymore.
Sure, no problem.
Best regards.
joe

Hi,
The purpose is to mix exhaust gases with the intake air to reduce local temperature peaks and, consequently, NOx production. However, in the specific case of suddenly releasing the throttle, the boost pressure may occasionally be higher than the exhaust pressure, allowing fresh air to directly enter the exhaust system. This likely suppresses the whistling sound of the VTG turbocharger, which some people in the forum actually enjoy. In theory, if the engine is only briefly off the throttle, it should be able to build boost pressure and power more quickly. However, I haven't noticed this. Because of the AGR's inertia, it should react more slowly when suddenly accelerating after a period of low load, as you experienced.

Hello TDIJOE!

I also own a T4 Caravelle, same year of manufacture, same engine, with approximately 60,000 km on the odometer. I noticed a slight improvement in acceleration from low speeds, but significant changes in performance are not to be expected. This measure should primarily prevent complete contamination of the intake manifold and valve openings. Here's a tip: Place a metal plate between the EGR valve and the pipe that leads to the exhaust manifold, because if you completely block the hose, the EGR valve might get stuck in a semi-open position due to pressure differences from outside air.

Best regards, Peter.

Thank you for the prompt feedback!
After extensive test drives, I'm now certain about the improved fuel efficiency.
Otherwise, my question has been completely answered.
I'll probably have to do something about the metal part, as I feel like the top speed isn't quite as high as it used to be (speedometer is about 3-5 km/h below the old V-max). Could the exhaust pressure be opening the valve on its own?!?!?
Nobody wants exhaust gases in the intake manifold when the engine is running at full load.
I completely removed the EGR valve and cleaned it. The sludge that built up over time, along with the oil, had created a really nasty buildup that was already reducing the pipe's diameter. But after a 2-hour cleaning session with gasoline and a toothbrush, the part looks like new. I highly recommend doing this. Expanding the T4 is not a simple task.
Best regards.
joe