Patent ID: 9243538
Filing Date: 2016-01-26
CPC Classification: F01N,F02B,F02D,F02M,Y02T

Claim Text:
1. A method comprising: operating an internal combustion engine to produce an exhaust gas flow through an exhaust system including at least one vanadia selective catalytic reduction (SCR) catalyst, an exhaust throttle upstream of the vanadia SCR catalyst, a turbocharger with a controllable wastegate upstream of the exhaust throttle, and an EGR control valve connected with an EGR conduit connecting the exhaust system to an intake system to control recirculation of the exhaust gas flow to the intake system; passing the exhaust gas flow directly to the vanadia SCR catalyst from the exhaust throttle without an intervening particulate filter upstream of the vanadia SCR catalyst and without an intervening oxidation catalyst upstream of the vanadia SCR catalyst; determining an NOx output in the exhaust gas flow downstream of the vanadia SCR catalyst; initiating a NOx output reduction event to reduce an NOx output by the internal combustion engine in response to the NOx output in the exhaust gas flow downstream of the vanadia SCR catalyst being greater than a threshold amount; and at least partially closing each of the wastegate and the exhaust throttle to execute the NOx output reduction event, thereby increasing an amount of exhaust gas flow recirculated to the intake system.