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DPF Regen question

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How do I know when my 535d is regenning?

 

I’ve just been made redundant, so my mileage has tumbled from about 800 miles a week to about 40, all of which is town stuff. Do I need to give it the beans on a run every so often, or is that a myth these days?

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Sorry about the job.

 

IIRC general consensus is a decent run (at least 20 mins?) so that everything is up to temp and then run at a consistent clip.

 

As Andrew says, exhaust note should deepen and sort of grumble for a bit but you really have to listen carefully to even notice it at all.

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The regen process on modern BMWs is more of a constant thing - it's not like a VW where it categorically regens every 400km, but it literally regens whenever it can.

I do low mileage in my 2013 525d, but it does get the occasional longer run, and I have zero DPF issues.

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Generally:

Exhaust note will deepen

The car will feel less "urgent" and "lumpy"

The gearbox will hold on to gears for a longer period than usual 

MPG drop

 

Parameters for Active and Passive Regen:

There are two kinds of regeneration:

  1. Continuous regeneration:

    This form of regeneration takes place during normal driving. At exhaust-gas temperatures of between 280-350°C, continuous regeneration takes place in the form of a slow oxidation process. The soot particles cannot be incinerated until the exhaust gases reach the required temperature.

  2. Periodic regeneration:

    Periodic regeneration is performed automatically by the DDE after no later than 1000 km (600 miles). On vehicles with many short-distance drives, periodic regeneration already starts taking place after just 400 - 800 km (250 - 500 miles).

    For regeneration, the intake air is reduced by the throttle valve. One or two post-injections are performed. This increases the exhaust-gas temperature to about 600 °C. The soot is incinerated with the residual oxygen.

    The periodic regeneration is performed at all speeds. The most efficient method is regeneration at a constant speed in excess of 60 km/h (38 mph) over a period of 20-30 minutes.

    The DDE calculates the time for periodic regeneration from the following values:

    • average distance travelled
    • average driving speed
    • temperature in the diesel particle filter
    • values from the exhaust gas pressure sensor

    The last successful regeneration can be read out by the diagnosis system

 

The following conditions must be fulfilled for a regeneration:

  • The coolant temperature must be in excess of 75 °C
  • the exhaust-gas temperature before the diesel particle filter must be greater than 240 °C
  • there must be enough fuel (fuel reserve indicator light is not lit up). Whenever the reserve lamp lights up, the regeneration process is suspended.
  • no fault codes from the air mass system, exhaust emission system and sensors must be saved in the DDE
  • The fault codes 480A / 245700 (from F01) and 481A / 245800 (from F01) must display the status "currently not present"
  • Constant driving speed above about 60 km/h (approx. 38 mph). The optimum speed is about 100 km/h (approx. 60 mph).

One of the main reasons these cars have issues with active regen to occur is the first one, you can check the coolant temperature through the secret dash menus which will give you a live read out of the temperature if it is struggling to get past low 80's then I would begin to think one of the thermostats is on it's last legs.

 

https://www.newtis.info/tisv2/a/en/f06-640d-cou_201503/wiring-functional-info/power-train/digital-diesel-electronics/exhaust-re-treatment/system-diesel-particulate-filter/EZjPC6cq

Edited by Ninja59

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Ha ha! My old Alfa 159 used to stink when it regenned, and the boost gauge used to fly around too!

 

the exhaust though, gained a lovely rumble. For an oil burner!

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I never heard my dads F10 530d do a regen, neither did he.  My dad has driven hundreds of thousands of miles in Diesel Mondeos and has never noticed a change in engine note from a regen.

 

Some engines will be very different from others of course and may get drowned out by tyre noise, road surface noise or your tunes.

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I usually notice my 6 doing it around 40mph as it drones more than usual, but usually the most obvious factor for me is it holding the gears for longer than it "usually" does and that happens long before the exhaust noise slightly changes. 

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I’ve done about 20k in my 535d and the only thing I’ve noticed on the (usually motorway) driving is the oil temp sitting about 5-10 degrees warmer than usual for a while every now and again. No idea if that’s it regenerating, or just environmental, but I’ve certainly never noticed a change to the exhaust note...

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