Method and system for EGR control

摘要

Methods and systems are provided for improving control of high dilution EGR. An intake plenum is divided so that fresh intake air and EGR can be delivered to engine cylinders via dedicated plenum portions. Distinct sets of throttles are provided in the cylinder intake ports coupled the different plenum portions so that a ratio of intake air flow and EGR flow to the engine cylinders can be rapidly adjusted in response to sudden changes (e.g., increase or decrease) in EGR demand.

主权项

1. A method for an engine, comprising:
delivering at least intake air into engine cylinders via a first section of a divided intake plenum; delivering at least EGR into the engine cylinders via a second, different, section of the divided intake plenum, wherein the first and second sections of the divided intake plenum are separated by a divider inside the divided intake plenum, the divider spanning an entire length of the divided intake plenum from upstream of an EGR passage to intake ports of the cylinders; and adjusting relative flow from the first section to the cylinders via a first set of throttle valves and from the second section to the cylinders via a second set of throttle valves, the first and second sets of throttle valves arranged in a perpendicular arrangement on a common shaft, the common shaft configured perpendicular to a plane of the divider.