Engine system, operating method and control strategy for aftertreatment thermal management

Abstract

A method of operating an internal combustion engine system includes passing exhaust gases from an engine to an aftertreatment device such as a particulate filter at an exhaust temperature less than a target temperature, and increasing a temperature of exhaust gases passing through the aftertreatment device to the target temperature by controllably restricting exhaust flow upstream the filter. The method still further includes generating a signal indicative of exhaust back pressure and reducing exhaust pressure by selectively reducing airflow to the engine responsive to the signal. An internal combustion engine system and associated control system includes an electronic control unit configured to selectively increase a temperature of exhaust gases passing through a particulate filter to a regeneration temperature via a variable flow restriction device. The electronic control unit is further configured to reduce exhaust pressure upstream the flow restriction device by commanding adjusting an intake airflow control element for the engine responsive to a signal corresponding to exhaust back pressure.