Method for operating a motor vehicle internal combustion engine with an exhaust particle filter

摘要

A method for operating a motor vehicle internal combustion engine with an exhaust system branch in which a wall-flow exhaust particle filter is arranged. An amount of ash and an amount of soot accumulated in the exhaust particle filter are continuously determined. An ash increase value characterizing an increase in the amount of ash is determined and if pre-set conditions are present, the operation of the internal combustion engine is changed over to a special operating mode for performing an ash detachment and transportation operation, in which operating variables of the internal combustion engine are set such that, on the exhaust entry side in the exhaust particle filter, a pre-settable minimum exhaust flow speed results at which detachment of ash attached to the channel walls of the exhaust particle filter and transportation of detached ash in the direction of the respective inlet channel end is made possible.

主权项

1. A method for operating a motor vehicle internal combustion engine with an exhaust system branch in which a wall-flow exhaust particle filter with inlet and outlet channels that are alternately closed at opposing ends and are separated from each other by porous channel walls is arranged, the method comprising:
continuously determining an amount of ash and an amount of soot accumulated in the exhaust particle filter; determining an ash increase value that characterizes an increase in the amount of ash; and if pre-set conditions are present, changing over the operation of the internal combustion engine to a special operating mode for performing an ash detachment and transportation operation, the special operating mode comprising
setting operating variables of the internal combustion engine and operating the internal combustion engine using the set operating variables such that on the exhaust entry side in the exhaust particle filter a pre-settable minimum exhaust flow speed results causing detachment of ash attached to the channel walls of the exhaust particle filter, transporting the detached ash in the direction of the respective inlet channel end, and depositing the transported, detached ash on the respective inlet channel end, andresetting the ash increase value with termination of the special operating mode, wherein the pre-set conditions for changing over the internal combustion engine operation comprises dropping below a pre-settable soot amount limit value for the amount of soot and exceeding a pre-settable ash increase limit value for the ash increase value.