DPF Differential Pressure slightly high

[quote] no tuning, no software update, 166,000 km
989 hPa ambient pressure, ambient temperature 18 degrees
Measurement blocks under menu: Engine control is disabled!
Oil volume 100ml
Maximum 407 hPa pressure difference
[Edit Admin: In my opinion, this is a bit too high for the mileage or fuel consumption volume]
Hello,

Thanks for the tip about the differential pressure adjustment for "dieselschrauber".
I believe the machine's performance is good across the entire speed range, meaning I haven't noticed any effects from high differential pressure on its handling or fuel consumption. Should I take any further measures (besides DPF cleaning)? I primarily use Aral-Diesel (Normal) for fueling, with an 99.9% ratio. Motor Oil = Fuchs 5W-30. The oil change interval since the vehicle was purchased (mileage 112,000) is a maximum of 20Tkm.

Regards, Petrol

Hi,

if the car is running well and nothing else seems wrong, I would continue driving and occasionally check the differential pressure, i.e. if it continues to increase.
It's also possible that the differential pressure sensor is faulty, or that the car has been modified (possibly by the previous owner).

It's also possible that this is simply normal for your engine. However, I don't recall seeing such a high value in other 2.0 TDI engines. Take a look in the forum to see if you can find values for your engine code.

However, you shouldn't worry about this. You only need to take action if the engine starts to regenerate constantly, the fuel consumption increases unexpectedly, or if you lose power in the upper speed range due to excessive differential pressure.

Best regards, Rainer

Hello,

The high differential pressure value piqued my interest. Therefore, here are my observations. In the diagram, curves (1) and (2) represent acceleration runs (full throttle) up to over 4000 RPM in 4th gear (1) and 5th gear (2), after which the throttle is immediately "released" – resulting in a corresponding low engine speed. The yellow points (3) come from a longer measurement run, during which I performed a slightly "damped" full throttle run over a period of time. The resulting torque and power are slightly below the vehicle's specifications. Furthermore, there are also longer sections with approximately 4000 RPM. The blue curve (4) represents the pressure development after an acceleration phase at 4000 RPM, followed by continued driving at approximately 4000 RPM.

The high differential pressure values in runs (1) or (2) are clearly peak values that arose due to the short acceleration phase (84km/h to 122km/h in under 10 seconds – 12 seconds = standard value). It is obvious that there was too much exhaust air available for the filter in a very short time, which could also indicate a restriction due to soot. When driving at constant high speeds, the pressure quickly drops and you end up with values below 200hPa. I haven't been able to find values for differential pressure (maximum permissible, speed-dependent standard values, values in a new engine, etc.).

Regards,
Petrol

Okay, if the differential pressure decreases after a few seconds of full throttle, that's better. Probably, you're not applying enough full throttle.

Unfortunately, with the "Full Throttle" setting, I can't achieve any improvement, as I don't want to damage the DSG gearbox. The acceleration within the normal values is satisfactory and sufficient.
[Correction for Petrol:
4th gear: 73km/h-124km/h, 8s (Curve 1)
5th gear: 77km/h-123km/h, 9s (Curve 2)
84km/h-122km/h, 10s (Curve 3)]

Hello,

If you maintain a constant speed of 4000/min, is that not then running at full load? --> Consequently, the differential pressure would naturally decrease due to the lower exhaust mass flow.
The relevant factor is only the acceleration under full load.
However, I generally agree with what Rainer wrote above. As long as nothing is amiss, continue and observe.

Best regards,
Albrecht

Hello,

What can I derive from the difference pressure value? Have you looked at the diagram with the measurement runs? For comparison with other vehicles, I believe only curve (3) is relevant, as I was trying to obtain the standard performance in this measurement run. I assume that the exhaust flow is directly proportional to the generated power. Since the generated power is above 125KW in curves (1) and (2), the exhaust volume should also be higher. The question is, is the filter actually designed to handle this temporarily increased flow volume without increasing the pressure?

A low volumetric flow rate in the particulate filter could be responsible for the increased pressure, then a higher value would also be observed at a constant high speed. What is the difference pressure in a comparable new vehicle at 4000 rpm? I haven't been able to find data for comparable vehicles (MKB: CFGB).

Regards,
Petrol

Hello,

So, if I understand correctly, from my point of view, curves 1 and 2 in your diagram are relevant.
That is, a maximum difference of 400 mbar in your case.
Causes can hardly be generalized and can be diverse.
- Soot loading
- Ash loading
- Filter volume in relation to power (tuning!)
- Filter material (silicon carbide, sintered metal, bent sheet in open systems, etc.)

The 400 mbar are indeed at the upper end of what is known (see difference pressure survey), but you must also consider it in relation to the behavior of the vehicle (especially regeneration frequency).
If there is nothing remarkable here, I wouldn't worry.
What could be the case with you and has already been mentioned is unknown tuning.

For comparison: my V6 TDI has also 400-500 mbar depending on soot loading, regenerates only every 1200-1400 km, very rarely less than 1000 km, fuel consumption is 7.5 - 8 liters/100 km.
Apparently, the DPF size in relation to the engine power in the C6 is quite small. Therefore, the difference pressure values are above the known range for R4 TDI engines.

Best regards,
Albrecht

PS: I just looked at the difference pressure survey again, the older 125 kW TDI engines seem to be relatively high in the range of the 2.0 l TDI (>300 mbar)

Hello,
I have extracted some values for the vehicle.
(approx. 166,500 km, 2.0 CR MKB: CFGB 6g-DSG)
Diesel particulate filter oil volume -> 0.10 l
Calculated soot mass -> 14.27 g
Measured soot mass -> minus! -0.21 g ??
Kilometers since last regeneration -> 288762 km
Fuel consumption since last regeneration -> 12.32 l
Counter for the regeneration time of the diesel particulate filter -> 0 s
[Quote: Albrecht]
What could be present and has already been mentioned is unknown modifications.

The vehicle was used for business purposes. I would rule out any modifications.

However, I have the VCDS capabilities to read data that suggests a change in the software.

Best regards, Petrol

Hello,

I find such a difference between measured and calculated Russ mass to be implausible, especially since the last regeneration was a few kilometers ago.

Is there anything in the error memory?

Best regards,
Albrecht

Hello,
no errors found, I read the data with VCDS. Am I doing something wrong? I'm looking for a way to measure emissions (before the software update). Do you have any tips?
Best regards, Petrol

[quote="Petrol"]Hello,
No errors found, I read the data with VCDS. Am I doing something wrong? I'm looking for a way to measure emissions (before the software update). Do you have any tips?
Regards, Petrol[/quote]
Check if the differential pressure (value + offset) is showing an error when the engine is off. If so, replacing the differential pressure sensor might be a good idea. If not, I would continue to drive until a real problem occurs, rather than wasting time and money on a pointless repair (= unnecessary action).

Best regards, Rainer

Hello,

Thank you for the message. I have selected "Differential Pressure" values (ignition on, engine off).

Address 01: Engine Electronics (03L 906 018 BD) 14:14:04
IDE00427: Particulate Filter: Differential Pressure 2 hPa
IDE00428: Particulate Filter: Offset for Differential Pressure 0 hPa
IDE03353: Particulate Filter Differential Pressure Sensor: Raw Voltage 1002.6 mV
IDE04263: Sender for Differential Pressure over Particulate Filter: Raw Value 0 hPa
IDE04650: Particulate Filter Differential Pressure Dynamic Offset -2 hPa

Is it correct that the differential pressure sensor is within the normal range?

Regards,
Petrol

Okay, I understand. Please provide the text you want me to translate, and I will translate only the readable text, leaving the HTML tags, BBCode tags, and URLs as they are.