Abstract: A catalyst control system includes a stop and start module that, during a period that the vehicle is ON between (i) a first time when the vehicle is turned ON and (i) a second time when the vehicle is next turned OFF, selectively shuts down and starts a spark ignition engine of the vehicle. A catalyst light off (CLO) control module initiates a first CLO event for a first engine startup during the period and, when a temperature of a catalyst that receives exhaust output by the engine is less than a predetermined temperature, selectively initiates a second CLO event for a second engine startup during the period. A fuel control module richens fueling of the engine during the first and second CLO events of the period. A spark control module retards spark timing of the engine during the first and second CLO events of the period.

Abstract: A catalyst control system includes a stop and start module that, during a period that the vehicle is ON between (i) a first time when the vehicle is turned ON and (i) a second time when the vehicle is next turned OFF, selectively shuts down and starts a spark ignition engine of the vehicle. A catalyst light off (CLO) control module initiates a first CLO event for a first engine startup during the period and, when a temperature of a catalyst that receives exhaust output by the engine is less than a predetermined temperature, selectively initiates a second CLO event for a second engine startup during the period. A fuel control module richens fueling of the engine during the first and second CLO events of the period. A spark control module retards spark timing of the engine during the first and second CLO events of the period.

Abstract: A system for a vehicle includes an oxygen storage capacity (OSC) determination module, a delay determination module, a correction module, and a fault detection module. The OSC determination module determines an OSC period of a catalyst of an exhaust system based on first and second amounts of oxygen measured using first and second oxygen sensors located upstream and downstream of the catalyst, respectively. The delay determination module determines a delay period of the second oxygen sensor. The correction module sets a corrected OSC period for the catalyst based on a difference between the OSC period and the delay period. The fault detection module selectively indicates that a fault is present in the catalyst based on the corrected OSC period.

Abstract: A system for a vehicle includes an oxygen storage capacity (OSC) determination module, a delay determination module, a correction module, and a fault detection module. The OSC determination module determines an OSC period of a catalyst of an exhaust system based on first and second amounts of oxygen measured using first and second oxygen sensors located upstream and downstream of the catalyst, respectively. The delay determination module determines a delay period of the second oxygen sensor. The correction module sets a corrected OSC period for the catalyst based on a difference between the OSC period and the delay period. The fault detection module selectively indicates that a fault is present in the catalyst based on the corrected OSC period.