AXR: Sudden gas cut-off, short post-injection?

Hello!

A possibly very silly question:

The injection process occurs at low partial load in the lowest gear.
The low tempo is very noticeable in the PD recording. A very quiet...
but still a piercing, harsh, metallic sound. It.
It disappears (of course) when you release the gas pedal and appears when there's little [something].
Accelerate or release the gas pedal just before the engine reaches idle speed.
If I'm in a low gear with our AXR engine (in a Polo 9N3, with ESP, no chip)...
If you suddenly turn off the gas, the noise will naturally disappear.
immediately, but I mean, just a very short time after that, for a brief moment.
A small amount is injected, and then the noise disappears.
Sure, here's the translation:

"Immediately."
Could that be possible? Instinctively, I would say a shock-absorbing...
Type in the measure.

Best regards, Klaus.

PS: If this is nonsense, just let the thread disappear into oblivion.

Hi Klaus,

You are absolutely right - I've described this topic here before...
Due to the play and torsion in the powertrain, this occurs in the same...
"at suggestion (positive or negative)" (Sudden load changes) can cause a vibration with a resonant frequency.
(=> Dependent on gear), which, without intervention from the MSG, exhibits the given, natural damping.
which lasts for quite a long time and is usually perceived as very annoying.
Keyword: "Bonanza effect", etc.
The MSG is now approaching this oscillation with a phase shift, meaning that when...
As the speed increases, the amount is reduced; as the speed decreases, the amount is increased.
The amount cannot be further reduced in this stage, so the only option is to proceed with the positive value. Percentage by weight.
remaining, which can be heard with "pointed ears."
The ASD intervention is time-limited (maximum 2-3 seconds) due to the torque-generating effect.
Injections without activation of the Positive Displacement Gear (PDG) are very precisely monitored by the internal monitoring system of the Master Sequence Generator (MSG), and if the amount released is not justified, it can lead to error messages in the fault memory.

With pointed ears, the NMK (Null Quantity Calibration) can also be performed on Piezo CR aggregates.
listen, during which, due to the surge of rail pressure, the system is driven to one of the 3 to 4 learning points.
The advance angle (AD) on the cylinder is varied/increased until combustion (resulting in uneven torque) is detected. If the thrust phase is still active, the next cylinder will be activated.
The noise from the MV (mechanical ventilation) units isn't very loud, so you usually don't hear anything.

=> With a good ear, you can achieve a lot!

Best regards, and keep your ears open.

PD90

I've noticed the same thing with my TDI engine in my A3.
Since I had run the cinch cables of the amplifier next to its power cable...
I could listen to the electrical noise of the ESP.
When the engine was turned off, a wave-like after-oscillation could be heard, which gradually became quieter.
Hats off to the engineers!

Tagessuppe wrote:

I've noticed the same thing with my TDI engine in my A3.

I was just trying to adjust the AFR (Air-Fuel Ratio) on my engine, specifically in the main fuel table (MWB 1), at the highest RPM setting.
I'm trying to find evidence for this (regarding the sampling rate), but either the AFN...
"For a 1997 model, this shouldn't happen, or it might not be coming from the MSG at all."

Best regards, Klaus.

And thank you very much to PD90 for the excellent answer.

Hi Klaus,

You're welcome!
I unfortunately only check in here sporadically (due to lack of time...).
I'm always very happy when you...
"You might also find something useful in the 'Experiences + Descriptions' section."

...and my karma could probably use a little help too...

Okay, see you soon!

Greetings, PD90.