Particle filter in the exhaust system of an internal combustion engine
View Patent ↗Various embodiments may include a method for regenerating a particle filter comprising: increasing a measured exhaust-gas temperature from a normal operation level to above a desorption start temperature defined by initiating release of sulfur compounds accumulated in the particle filter; monitoring a particle mass in the exhaust-gas flow downstream of the particle filter; comparing the particle mass to a predefined threshold value above which the formation of white smoke can be expected; if the threshold value is exceeded, setting the exhaust-gas temperature to a desorption temperature for release of sulfur compounds until the particle mass falls below the threshold; if the particle mass threshold value is not exceeded, setting the exhaust-gas temperature to a regeneration temperature for burning-off of the particle loading of the particle filter for a predetermined time period; and after the time period has elapsed, ending the regeneration by lowering the temperature to the normal operation level.
1. A method for the regeneration of a particle filter in an exhaust system of an internal combustion engine during operation, the method comprising:
starting a regeneration phase by increasing a measured exhaust-gas temperature from a normal operation level to a temperature value above a desorption start temperature at which sulfur compounds accumulated in the particle filter begin to release;
monitoring a particle mass contained in an exhaust-gas flow downstream of the particle filter with an electrostatic particle mass sensor arranged in the exhaust-gas flow; comparing the particle mass to a predefined particle mass threshold value associated with white smoke formation;
if the particle mass threshold value is exceeded, setting the exhaust-gas temperature to a desorption temperature for release of sulfur compounds accumulated in the particle filter until the particle mass falls below the particle mass threshold value;
if the particle mass threshold value is not exceeded, setting the exhaust-gas temperature to a regeneration temperature for burning-off of the particle loading of the particle filter for a predetermined time period; and
after the predetermined time period has elapsed, ending the regeneration phase by lowering the measured exhaust-gas temperature to the normal operation level.
2. The method for the regeneration of a particle filter as claimed in claim 1 , wherein the exhaust-gas temperature is increased to the desorption temperature to start the regeneration phase.
3. The method for the regeneration of a particle filter as claimed in claim 1 , wherein the exhaust-gas temperature is increased to the regeneration temperature to start the regeneration phase.
4. The method for the regeneration of a particle filter as claimed in claim 1 , wherein the desorption temperature lies in a temperature range of 300° C. to 500° C.
5. The method for the regeneration of a particle filter as claimed in claim 1 , wherein the regeneration temperature lies in a temperature range of 550° C. to 750° C.
6. The method for the regeneration of a particle filter as claimed in claim 1 , wherein, if the particle mass threshold value is exceeded, the exhaust-gas temperature is regulated based on the particle mass such that the particle mass remains below the particle mass threshold value but above a lower particle mass limit value set to avoid formation of white smoke.
7. The method for the regeneration of a particle filter as claimed in claim 1 , wherein the exhaust-gas temperature is set or regulated by an electronic engine control unit depending at least in part on the measured exhaust-gas temperature and on the particle mass.
8. The method for the regeneration of a particle filter as claimed in claim 1 , wherein the electrostatic particle mass sensor comprises electrodes spaced apart from one another forming an electric field through which a part of the exhaust-gas flow is conducted; and
wherein electrical charges are transmitted between the electrodes, generating an electrical signal proportional to a particle mass and to a sulfur content of the exhaust-gas flow.