Method for operating a particulate filter disposed in an exhaust-gas region of an internal combustion engine and device for implementing the method

Abstract

A method for operating a particulate filter disposed in an exhaust-gas region of an internal combustion engine and a device for implementing the method. Based on an oil signal provided by an oil sensor, an oil-consumption determination determines the oil consumption of the internal combustion engine. From the oil signal, an ash-load determination calculates a measure for the ash-load state of the particulate filter, which can be taken into account for the operation of the particulate filter, particularly in establishing a threshold value for the maximum permissible particulate-load state. Moreover, a filter replacement signal can be obtained from the ash-load state.

1 . A method for operating a particulate filter situated in an exhaust-gas region of an internal combustion engine, the method comprising: 
 using an oil sensor to detect an oil level of the internal combustion engine;    using an oil-consumption determination unit to determine an oil-consumption signal as a measure for an oil consumption of the internal combustion engine, based on an oil signal provided by the oil sensor; and    using an ash-load determination unit to determine a measure for an ash-load state of the particulate filter, based on the oil-consumption signal.    
   
   
       2 . The method according to  claim 1 , further comprising using a particulate-load determination unit to determine a particulate-load state of the particulate filter, the ash-load state being taken into consideration when determining the particulate-load state.  
   
   
       3 . The method according to  claim 2 , wherein the particulate-load state is determined from a pressure difference occurring at the particulate filter.  
   
   
       4 . The method according to  claim 3 , further comprising: 
 detecting an exhaust-gas pressure upstream of the particulate filter by a pressure sensor; and    determining an exhaust-gas pressure downstream of the particulate filter with reference to a model that takes into account an ambient-air pressure.    
   
   
       5 . The method according to  claim 2 , wherein a measure for a temperature in the particulate filter is taken into consideration when determining the particulate-load state.  
   
   
       6 . The method according to  claim 1 , further comprising establishing a threshold value predefined for a maximum permissible particulate-load state of the particulate filter as a function of the determined ash-load state.  
   
   
       7 . The method according to  claim 1 , further comprising using a particulate-filter service-life determination unit to determine and indicate a filter replacement signal, based on the ash-load state.  
   
   
       8 . A device for operating an internal combustion engine, comprising: 
 an oil sensor to detect an oil level of the internal combustion engine; and    at least one control device including an oil-consumption determination unit and an ash-load determination unit, the oil-consumption determination unit to determine an oil-consumption signal as a measure for an oil consumption of the internal combustion engine, based on an oil signal provided by the oil sensor, the ash-load determination unit to determine a measure for an ash-load state of a particulate filter, based on the oil-consumption signal.    
   
   
       9 . The device according to  claim 8 , wherein the oil signal is at least one measure for the oil level of the internal combustion engine.  
   
   
       10 . The device according to  claim 8 , further comprising a differential-pressure sensor situated upstream of the particulate filter for determining a pressure difference between an exhaust-gas pressure upstream of the particulate filter and an ambient-air pressure.