The software applications of the engine control units since DDE5 always co-ordinate the management of particle filter regeneration. This means that, in principle and without the driver having to take any action, the system is able to ensure optimised regeneration operation over the entire utilisation phase of the engine. In individual cases (e.g. customer complaints), a service regeneration can be requested in the workshop. To enable service regeneration of the particle filter, regeneration must be requested in the DDE control unit. This is requested using this service function.
The regeneration is requested in that the consumed fuel since the last regeneration is set to a maximum value in the DDE control unit.
The regeneration is started at the next trip as soon as the coolant temperature has reached a value of at least 75 °C and the exhaust-gas temperature before cat. has reached a value of at least 240 °C. Moreover, the fuel level must be at least 10 litres.
The best possible effect of the regeneration is achieved if the vehicle is operated for around 20 minutes at a speed of at least 60 kph that is as constant as possible as of the start of the regeneration. Experience has shown that non-urban driving achieves the best regeneration results.
The current state of any regeneration block, of a regeneration request in the control unit and the regeneration itself can be displayed both in the service function ”Regeneration of particle filter” and in the DDE diagnosis request at the point ”Regeneration particle filter”. Moreover, the distance driven since the last regeneration can be read out.
The following possible states on regeneration are displayed:
The following possible statuses of the regeneration are displayed:
Notes:
In the event of a prematurely cancelled regeneration, the regeneration is started in the next drive cycle as soon as the coolant temperature has returned to a value of 75 °C and the exhaust-gas temperature before cat. has returned to a value of 240 °C.
In the case of a particle filter heavily loaded with soot, it can occur that the regeneration request is blocked again after a short time or is not released.
In this case, it is required to regenerate the particle filter in a motorway / or cross-country trip taking approx. 30 minutes at a speed that is a constant as possible.
Subsequently, the service function ”Regeneration particle filter” must be run again.
Moreover, it also occurs that with a particle filter heavily soiled with soot the exhaust-gas back-pressure becomes so high that problems can occur on reaching breakaway speed. In many cases, this impairs the feasibility of the exhaust backpressure test. A clean regeneration reduces the effect of this problem in many cases and lowers the exhaust-gas back-pressure.
During the regeneration phase and with the engine running, it can also occur that the display for 'Regeneration active' jumps to 'Regeneration not active'. This behaviour can be seen exclusively with the vehicle stationary with the engine running. This behaviour does not impair the scheduled course of the regeneration in general.