Engine controls for exhaust aftertreatment thermal management

An engine system comprising:

• an engine configured for vehicle propulsion and including a plurality of cylinders;
• a plurality of fuel injectors configured to provide fuel to respective ones of the plurality of cylinders;
• a compression brake coupled with at least a first set of the plurality of cylinders;
• an exhaust aftertreatment system including a catalyst;
• and
• an electronic control system configured to:
• operate the engine in an idle coast mode wherein the engine is decoupled from a road load with the vehicle coasting downhill;
• determine a condition for regeneration of the catalyst;
• and
• in response to the condition for regeneration of the catalyst, transition operation of the engine to a brake-fuel mode wherein the compression brake is actuated to provide compression braking of the first set of the plurality of cylinders and a second set of the plurality of cylinders receive and combust fuel provided from respective ones of the plurality of fuel injectors;
• wherein the transition occurs while maintaining the idle coast mode.

A method comprising:

• providing an engine system including an engine including a plurality of cylinders, a plurality of fuel injectors configured to provide fuel to respective ones of the plurality of cylinders, a compression brake coupled with at least a first set of the plurality of cylinders, and an exhaust aftertreatment system including a catalyst;
• operating the engine in a first mode wherein the engine operates at a rated speed and a light load being 50% or less than a rated torque with the plurality of fuel injectors providing fuel to each of the plurality of cylinders;
• determining a condition for regeneration of the catalyst;
• and
• in response to the act of determining, transitioning operating the engine to a brake-fuel mode wherein the compression brake is actuated to provide compression braking of the first set of the plurality of cylinders and a second set of the plurality of cylinders receive and combust fuel provided from respective ones of the plurality of fuel injectors;
• wherein the act of transitioning maintains operation of the engine at the rated speed plus or minus 2.5% or less.

An engine system comprising:

• an engine including a plurality of cylinders;
• a plurality of fuel injectors configured to provide fuel to respective ones of the plurality of cylinders;
• a compression brake coupled with at least a first set of the plurality of cylinders;
• an exhaust aftertreatment system including a catalyst;
• and
• an electronic control system configured to:
• operate the engine in a first mode wherein the engine operates at a rated speed and a light load being 50% or less than a rated torque with the plurality of fuel injectors providing fuel to each of the plurality of cylinders;
• determine a condition for regeneration of the catalyst;
• and
• in response to a condition for regeneration, transition operation of the engine to a brake-fuel mode wherein the compression brake is actuated to provide compression braking of the first set of the plurality of cylinders and a second set of the plurality of cylinders receive and combust fuel provided from respective ones of the plurality of fuel injectors,
• wherein during the transition the electronic control system maintains operation of the engine at the rated speed plus or minus 2.5% or less.