DPF differential pressure slightly high

Quote:

No tuning, not yet with software update, 166,000 km. Atmospheric pressure: 989 hPa. Ambient temperature: 18 degrees Celsius. Measurement blocks under the "Engine Control" menu are disabled! Oil ash volume: 100 ml. Maximum 407 hPa pressure difference [Edit Admin: In my opinion, this is a bit too much for the mileage or oil ash volume].

Hello,

Thank you for the information about the differential pressure, as mentioned by "dieselschrauber."
"In my opinion, the machine's performance is good across the entire speed range; I can't detect any effects of the high differential pressure on driving behavior or fuel consumption. Should I take any countermeasures (other than DPF cleaning)? I almost exclusively use Aral diesel (standard grade), and the engine oil is Fuchs 5W-30. Since purchasing the vehicle (mileage: 112,000 km), the maximum oil change interval has been 20,000 km."

Best regards, Petrol.

Hi,

If the car is running well and you don't notice anything else unusual, I would continue driving and periodically check to see if the maximum differential pressure continues to increase.
Possibly, the differential pressure sensor is faulty, or the car has been modified (perhaps by a previous owner) without your knowledge.

It might just be normal for your engine, but I don't recall seeing such a high value in other 2.0 TDI engines. Take a look in the relevant forum section to see if you can find values for your specific engine code.

As I said, you shouldn't worry too much about it. There's no need to take action unless the engine starts regenerating constantly, fuel consumption unexpectedly increases, or you experience a loss of power in the higher RPM range due to excessive differential pressure.

Best regards, Rainer.

Hello,
der hohe Differenzdruckwert hat mich dann doch neugierig gemacht. Deshalb hier meine Beobachtungen. Im Diagramm sind Kurve (1) und (2) Beschleunigungsfahrten (Vollgas) bis über 4000 U/min 4.Gang(1) 5.Gang(2), danach sofort „Gas weg“ ->Motordrehzahl entsprechend niedrig. Die gelben Punkte (3) stammen aus einer längeren Messfahrt, bei der ich in einem Zeitabschnitt einen etwas „gedämpften“ Vollgaslog absolviert habe. Das erzielte Drehmoment und die Leistung liegen dabei etwas unter den Fahrzeugnormwerten. Weiterhin sind längere Abschnitte mit ca. 4000 U/min enthalten. The blue curve (4) represents the pressure profile after an acceleration phase to 4000 rpm, followed by continued operation at approximately 4000 rpm.
Die hohen Differenzdruckwerte bei den Fahrten (1) oder (2) sind offensichtlich Spitzenwerte die aufgrund der zeitlich kurzen Beschleunigungsphase entstanden sind (84km/h-122km/h in unter 10s.->12s=Normwert). Offensichtlich war für den Filter zuviel Abgasluft in zu kurzer Zeit vorhanden, was auch für wenig Querschnitt-Einengung aufgrund Ruß sprechen könnte. Fährt man weiter bei konstant hohen Drehzahlen baut sich der Druck schnell ab und man landet bei unter 200hPa. WeI have not yet found any information regarding differential pressure values (maximum permissible values, speed-dependent standard values, values for a new engine condition, etc.).

Best regards, Petrol.

Okay, if the differential pressure decreases after a few seconds of full throttle, that looks better. Probably you are not using full throttle often enough.

Unfortunately, I can't promise any improvement in terms of performance, as I don't want to damage the DSG transmission. The acceleration within the normal range is fine and sufficient.
[Korrektur v. Petrol:
4th gear, 73 km/h - 124 km/h, 8 seconds (Curve 1).
5th gear, 77 km/h - 123 km/h, 9 seconds (Curve 2).
84 km/h - 122 km/h, 10-second curve (3).

Hello,

If you continue driving at a constant speed of 4000 RPM, it's no longer operating at full load. Consequently, the differential pressure decreases due to the lower exhaust mass flow rate.
Only the acceleration under full load is relevant.
Basically, I agree with what Rainer wrote above. As long as nothing seems unusual, continue driving and observe.

Best regards,
Albrecht.

Hello,
was kann ich dann aus dem Differenzdruckwert ableiten? Hast Du Dir das Diagramm mit den Messfahrten angeschaut? Für Vergleichszwecke mit anderen Fahrzeugen ist m.E. nur die Kurve (3) relevant, da ich bei dieser Messfahrt versucht habe die Standardleistung abzurufen. Ich nehm mal an, dass der Abgasstrom in direkter Beziehung zur erzeugten Leistung steht. Da die erzeugte Leistung bei Kurve (1) und (2) über den 125KW liegt sollte das Abgasvolumen auch höher sein. DThe question is whether the filter is actually sized to handle this temporarily increased flow rate without causing an increase in pressure.
A low particulate filter flow rate could be responsible for the pressure buildup, but in that case, an increased value would also be observed at a constant high engine speed. What is the differential pressure in a comparable new vehicle at 4000 RPM? I have not yet found data for comparable vehicles (engine code: CFGB).
Best regards, Petrol.

Hello,

Okay, if I understand you correctly, from my perspective, curves 1 and 2 in your diagram seem relevant.
That means a maximum differential pressure of 400 mbar in your case.
It is difficult to generalize about the causes, and they can be very diverse.
- Soot loading.
- Ash loading
- Filter volume in relation to performance (tuning!).
- Filter material (silicon carbide, sintered metal, bent sheet metal for open systems, etc.).

While 400 mbar is on the higher end of what's typically known (see differential pressure survey), it also needs to be considered in relation to the vehicle's behavior, especially the regeneration frequency.
If there's nothing unusual here, I wouldn't worry about it.
What might be the issue with your device, and which has already been mentioned, is unknown tuning.

For comparison: my V6 TDI also has pressures of 400-500 mbar depending on the soot load, and it only regenerates every 1200-1400 km, very rarely less than 1000 km. The fuel consumption is between 7.5 and 8 liters per 100 km.
Apparently, the size of the DPF in the C6 is quite small relative to the engine's power output. This explains why the differential pressure values are higher than those typically seen in R4 TDI engines.

Best regards,
Albrecht.

P.S.: I just re-examined the differential pressure survey, and it seems that the older 125 kW TDI engines all show relatively high readings within the 2.0L TDI range (greater than 300 mbar).

Hello,
I have read out some values from the vehicle.
(approximately 166,500 kilometers, 2.0 CR engine, transmission code: CFGB, 6-speed DSG).
Oil ash volume -> 0.10 L
Soot mass calculated: 14.27 g.
Soot mass measured -> negative! -0.21 g??
Kilometers since last regeneration -> 288762 m.
Fuel consumption since last regeneration: >12.32 liters.
Diesel particulate filter regeneration time counter -> 0 seconds.

[Quote: Albrecht]
What might be the issue with your device, and which has already been mentioned, is unknown tuning.

The vehicle was used for business purposes. I would rule out any modifications or tuning.
However, does VCDS offer any features that allow me to read data suggesting a software change?

Sincerely,
Petrol

Hello,

I find such a difference between the measured and calculated Russian mass to be implausible, especially considering that the last regeneration was quite some kilometers ago.

Is there anything in the error memory?

Best regards,
Albrecht.

Hello,
"No errors found; the measurement data was read out using VCDS. Am I doing something wrong? I'm looking for a way to perform an emissions test (before the software update). Do you have any suggestions?"
Sincerely,
Petrol

Petrol wrote:

Hello, "No errors found; the measurement data was read out using VCDS. Am I doing something wrong? I'm looking for a way to perform an emissions test (before the software update). Do you have any suggestions?" Sincerely, Petrol

Check if the differential pressure (value + offset) is noticeably different when the ignition is on but the engine is off. If it is, replacing the differential pressure sensor might be a good idea. However, if it's not, I would continue driving until a real problem arises and avoid unnecessary troubleshooting ("looking for a needle in a haystack").

Best regards, Rainer.

Hello,
Thank you for the message. I have selected values for "differential pressure" (ignition on, engine off).
Address 01: Engine Control Module (03L 906 018 BD) 14:14:04
IDE00427 Particle filter: Differential pressure 2 hPa.
IDE00428 Particle filter: Differential pressure offset 0 hPa.
IDE03353 Particle filter differential pressure sensor: Raw voltage 1002.6 mV.
IDE04263 Differential pressure sensor after particulate filter: Raw value 0 hPa.
IDE04650 Particle filter differential pressure dynamic offset -2 hPa.

Is it correct that the differential pressure sensor is within its normal operating range?
Best regards, Petrol.

Does it fit ?