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

A method of operating an internal combustion engine system comprising the steps of:

• passing exhaust gases from an internal combustion engine through an aftertreatment device at an exhaust temperature less than a target temperature;
• increasing a temperature of exhaust gases passing through the aftertreatment device to the target temperature at least in part by controllably restricting exhaust flow upstream of the aftertreatment device;
• generating a signal indicative of exhaust back pressure during the step of controllably restricting exhaust flow;
• reducing exhaust pressure at least in part by selectively reducing airflow to the engine in a manner that is responsive to the signal;
• recording exhaust back pressure data during controllably restricting exhaust flow, and recording position data for an intake airflow control element located upstream the engine during reducing exhaust pressure.

An internal combustion engine system comprising:

• an internal combustion engine having an exhaust outlet pathway, and an intake pathway including an intake manifold;
• an aftertreatment device positioned within said exhaust outlet pathway;
• a flow restriction device for increasing a temperature of exhaust gases from said engine positioned within said exhaust outlet pathway upstream of said aftertreatment device, said flow restriction device having at least two states, including an open state associated with a relatively lower exhaust back pressure and a restricted state associated with a relatively higher exhaust back pressure;
• an intake airflow control element positioned upstream of said engine and configured to control an intake manifold pressure which is proportional to the exhaust back pressure;
• and
• a control device operably coupled with said intake airflow control element to selectively divert airflow from the engine responsive to an increased intake manifold pressure occurring in response to adjusting the flow restriction device from the open state to the restricted state.

A control system for thermal management of an aftertreatment device of an internal combustion engine comprising:

• an electronic control unit configured to selectively increase a temperature of exhaust gases passing through the aftertreatment device to a target temperature at least in part via commanding adjusting of a variable flow restriction device fluidly between the engine and the aftertreatment device from a relatively more open state to a relatively more restricted state;
• and
• an indicating device configured to output a signal indicative of exhaust back pressure upstream of said flow restriction device, and indicative of an increased intake manifold pressure occurring in response to adjusting the flow restriction device to the relatively more restricted state;
• said electronic control unit being further configured to reduce exhaust pressure upstream said flow restriction device via commanding opening an intake airflow control element for the engine such that intake air is diverted from the engine in a manner that is responsive to the signal.