METHOD AND SYSTEM FOR SECONDARY AIR INJECTION COORDINATION WITH EXHAUST BACK PRESSURE VALVE

摘要

Methods and systems are provided for controlling and coordinating control of a post-catalyst exhaust back pressure valve and secondary air injection to expedite catalyst heating. By adjusting the exhaust back pressure valve to increase the exhaust backpressure and injecting secondary air into an exhaust passage upstream of the catalyst during cold start conditions, exhaust catalyst activation may be expedited.

主权项

1. A method for an engine comprising:
during an engine cold-start, adjusting an exhaust back pressure valve position based on a desired exhaust back pressure; determining an actual exhaust back pressure upstream of the valve; delivering a desired secondary air amount into an exhaust passage upstream of a catalyst based on the actual exhaust back pressure; and adjusting a fuel injection amount and a spark timing based on the actual back pressure.