Diesel Particulate Filter

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The DPF is designed to combat soot that is created by the diesel engine. The DPF is a honeycomb design that collects the soot and stores it to be burned off at a predetermined time. The DPF goes through a regeneration phase which burns off the soot collected within the filter. The DPF is located close to the engine to increase its efficiency by using the heat generated by the engine to help in the regeneration phase. The DDE initiates the regeneration phase depending on several factors. The regeneration phase will occur approximately every 500 miles. The DPF is also monitored by pressure sensors installed in the filter. Monitoring of the DPF begins when the exhaust gas and DPF temperature reach a predetermined value. If the differential pressure within the DPF surpasses a defined value within a predetermined amount of time a regeneration phase is initiated. During a regeneration phase the exhaust temperature is increased by post injection events. Diesel fuel is injected after combustion has taken place increasing the exhaust temperature in turn burning off the accumulated soot in the DPF. During the regeneration phase a small loss of power may be experienced for a short amount of time.

The DPF and DOC are combined on newer diesel engines, limiting the number of components within the exhaust system. On the E70 X5 the low pressure EGR is fed off of the DPF/DOC this setup is only found on this model due to the possibility of the vehicle being used for towing.

DPF replacement DDE 7.x

After replacing the particle filter, the corresponding service function are performed. This ensures that the particulate filter for the specific values in the DDE control unit, such as the calculated amount of soot in the particulate filter, will be reset to zero or default value.

Resetting of the values is done automatically, while performing the service function.

CBS-New Strategy:

With the introduction of the new CBS strategy for BMW diesel vehicles (first application: in E70 from 09/2006), the remaining mileage of the particle filter via the control unit functions are read. Since the particle filter does not belong to the CBS-scale, by two new failures on the limited remaining availability noted:

• Fault 452A appears as the particle filter most of the mileage has exceeded maximum and serves as information / reference for the filter in a BMW expert workshop to be replaced.

• 4D4A Fault appears as despite the request for the replacement filter no measures are taken and the total mileage of the particle filter is exceeded.

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