Patent ID: 9512764
Filing Date: 2016-12-06
CPC Classification: F01N,Y02A,Y02T

Claim Text:
1. A method for an engine with an SCR catalyst, comprising: in response to a vehicle-off event, injecting ammonia via an injector during a final exhaust blowdown of a cylinder selected based on firing order until a predetermined value of ammonia is stored in the SCR catalyst; in response to a subsequent vehicle-on event where an amount of ammonia stored in the SCR catalyst is less than the predetermined value, injecting ammonia via the injector until the predetermined value of ammonia is stored in the SCR catalyst; and in response to a thermal event where the vehicle-on event does not occur, and when a temperature of the SCR catalyst is less than an upper temperature threshold, injecting ammonia via the injector until a target value of ammonia is stored in the SCR catalyst, wherein the target value of ammonia is based on the amount of ammonia stored in the SCR catalyst and a temperature in the SCR catalyst following the thermal event.