Combined engine out NO_Xmanagement

摘要

An apparatus for controlling engine operations to a low NOx output amount at low selective catalytic reduction (SCR) temperature values and alternatively for controlling engine operations in an EGR cooler bypass regime at low engine load levels is described. The apparatus includes a controller that interprets a present speed and a present load of an engine, that determines an engine operating region in response to the present speed and the present load, and that provides an EGR cooler bypass command that provides EGR cooler bypass flow in response to the engine operating region being a first, low load, region. The controller operates the engine with supplemental NOx management in response to the engine operating region being a second, intermediate load, region. The controller operates the engine without either of the EGR cooler bypass or the supplemental NOx management in response to the engine operating region being a third region.

主权项

1. A method, comprising:
operating an engine to produce an exhaust flow; interpreting a present engine speed and a present engine load; determining an engine operating region in response to the present engine speed and the present engine load; operating the engine with an EGR cooler bypass and bypassing an EGR cooler with exhaust flow recirculated to the engine in response to the engine operating region being a first region; operating the engine with supplemental NOx management and reducing a NOx output of the engine in response to the engine operating region being a second region; and operating the engine without the EGR cooler bypass and without the supplemental NOx management in response to the engine operating region being a third region.