Mazda 6 Facelift 2005, Training Manual

Page: 87 / 274

Engine Diesel Engines
Regeneration Control
•
The regeneration control determines the soot amount accumulated in the DPF and
subsequently starts the regeneration process. The regeneration control is integrated in
the PCM.
Soot Amount Calculation
•
The PCM receives information about the soot amount accumulated in the filter from the
DPF differential pressure sensor. In order to establish the soot emission of the engine,
the PCM evaluates the customers driving method by monitoring the engine load, engine
speed and vehicle speed. In addition, the PCM calculates the soot amount burnt off in
the DPF using the signals from the HO2S and the exhaust gas temperature sensors.
•
Depending on the signal from the DPF differential pressure sensor, the calculated soot
emission, the burnt-off soot amount and the distance travelled, the PCM decides whether
and when a regeneration should be carried out. In this way, the filter does neither
become blocked nor damaged by a violent regeneration following an over-accumulation
of soot. As a result, it is possible to maintain the long-term integrity of the DPF while
achieving minimum fuel consumption, minimum oil dilution and optimum engine
performance.
•
If the soot accumulation rate in the DPF is 80 % or more, the DPF indicator light
illuminates. In this case an automatic regeneration of the DPF must be performed by
driving the vehicle at an engine speed of 2000 min
-1
or more and a vehicle speed of
40 km/h or more for approx. 10…15 min. As soon as the automatic regeneration process
starts, the DPF indicator light turns off.
NOTE: Although the DPF indicator light turns off when the automatic regeneration is started,
the regeneration process is continued until the soot accumulation rate decreases to
60 % or less.
NOTE: If the customer complains that the DPF indicator light illuminates frequently, he must
be informed to change the driving method (they should drive the vehicle at middle or
high engine speeds for a longer distance), so that regeneration of the DPF is
enabled.
•
If the soot accumulation rate in the DPF reaches 100 % or more, the DPF indicator light
flashes and DTC P2458 is stored in the PCM. In addition, the PCM reduces the fuel
injection amount to lower the exhaust gas temperature, preventing the filter from
overheating. Due to the reduced injection amount the soot emission of the engine and
hence the soot amount accumulated in the filter is also reduced. In this case a manual
regeneration of the DPF must be performed.
Service Training Mazda6 Facelift 01-73