Mini_DV6 diesel particle filter system

System, function and component installation:

The diesel particle filter is fitted in the center of the vehicle on the front of the engine directly below the exhaust turbocharger. As opposed to the diesel particle filter systems for exhaust gas treatment (particle reduction) used in BMW vehicles, the system in this vehicle requires a fuel additive in order to lower the burn-off temperature of the particles to such a level that the burn-off is possible at considerably lower temperatures. The particles consist mainly of diesel soot; in the regeneration phase, this is burned together with oxygen to produce gaseous CO2. The non-flammable residues of the additive are deposited in the filter itself. This means that the filter has a limited total distance (service life). The remaining distance life of the particle filter can be determined using the control module function <Status total remaining distance>. Furthermore, on the present system there are no oxygen sensors to measure the air characteristics and also no throttle valves to increase the exhaust-gas temperature. (Note: there are still throttle valves, but these have another purpose.) The diesel particle filter / additive system in the present vehicle consists of the following components:

• In a shared housing (material: silicon carbide): oxidation catalytic converter and particle filter
  
• For detection of the filter load: exhaust-gas differential pressure sensor. (This represents the exhaust backpressure sensor in BMW vehicles)
  
• For detection of the exhaust-gas temperature: exhaust gas temperature sensor (note: the combustion temperature is highest in the center of the housing; this is where the sensor is fitted.)
  
• In a separate housing below the fuel tank: additive reservoir and additive pump
  

The present system supports compliance with the exhaust emission regulation EU4.

Mixing the additive:

The additive is mixed with the diesel fuel by means of a separate pump system. The additive pump is activated via the LIN bus by the engine control module. Activation leads to drop-by-drop injection of the additive into the fuel tank. The function of the additive pump can be checked using <Component activation>/<additive pump>. The additive mixing procedure generally takes place after every refuelling with diesel fuel at a service station. This refuelling is detected via the fuel level sensor present in the fuel tank. On activation of the pump, a quiet activation noise is always audible.

Service and diagnosis instructions:

• 1.) The additive in the additive reservoir must be topped up / replaced at the end of its availability. The remaining availability of the additive level can be seen in the CBS data. After inserting a new bag of additive, the service function <Output correction additive level> must be executed so that the additive supply lines are bled!
  

• 2.) In most fault cases of the types message fault of the communication from DDE with additive pump (via LIN bus), blocked additive pump, critical or low fill level, power supply fault of the additive pump, internal additive pump fault, etc., the CC messages ”Particle filter” or ”Additive tank empty” appear. In these cases, it is not permitted to replace the particle filter! The first measure in such cases is to check the additive fill level via CBS, to check the communication lines for mechanical faults, and to check the function of the pump (using the control module function <Component activation>/<additive pump> as well as to work through the test module <Diesel particle filter/additive system>/<additive pump>)!
  

• 3.) After replacement of the additive pump within the framework of repairs, the additive system must be bled!
  

• 4.) After every replacement of the bag of additive, the additive fill level must be reset via CBS!
  

Filter load detection:

The load status of the particle filter is calculated in the control modules by the following parameters:

• Driving profile of the customer
  
• Exhaust backpressure, differential pressure
  

Important in the event of filter replacement!

After replacement, retrofitting or installation of a new particle filter, the service function <Replacement particle filter> must be executed so that the learning values for the particle filter are reset. This is the only way to ensure problem-free operation of the particle filter system!

Regeneration mode and regeneration frequency:

The regeneration phase of the particle filter (i.e. the burn-off of the diesel soot deposits) starts as soon as the regeneration has been requested and enabled by the engine management system (check via the diagnosis requests <Request regeneration particle filter> as well as <Release regeneration particle filter>). The regeneration starts at the latest on reaching the coolant temperature of 110 °C, the exhaust-gas temperature of 500 °C and a speed of at least 60 kph.

The current status of the regeneration can at all times be seen at <Status regeneration particle filter>. The frequency of the regenerations depends mainly on the driving profile. In the most economical driving profile (motorway and overland driving), regeneration takes place approximately once per 1000 driven kilometres. In the least economical driving profile (stop-and-go), regeneration takes place approximately once per 250 driven kilometres.

Furthermore, the diagnosis request <Status last regeneration> provides an indication of what distance has been driven since the last successful regeneration.

Important with filter load!

One-sided stop-and-go traffic can lead to irregular and frequently omitted regenerations, as with this driving profile the temperature thresholds necessary for a regeneration are reached less frequently. The particle filter can get clogged! Vehicle operation without adequate injection of additive to the fuel also leads to a clogged particle filter. A forced regeneration can be initiated using the service function <Regeneration particle filter> and a subsequent regeneration trip. If applicable, the customer should be notified regarding the unfavourable driving profile!