NSC CONTROL [SKYACTIV-D 1.8]

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Purpose, Function

• The NSC (NOx Storage Catalyst) adsorbs the NOx exhausted from the engine into the NSC.

• The PCM performs NOx reduction control periodically to break down NOx stored in the NSC (DENOx control).

• The PCM performs SOx reduction control periodically to break down SOx accumulated in the NSC (DESOx control). SOx reduction control is performed at the same time as diesel particulate filter regeneration control.

Block diagram

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Operation

• The PCM estimates the NOx amount stored in the NSC.

• The NOx storage amount is calculated based on the engine speed, intake airflow amount, fuel injection amount, exhaust flow amount, and the NSC temperature.

DENOx control

• When all of the following conditions are met, the PCM performs DENOx control.

DENOx control implementation condition

― Engine warmed up (engine coolant temperature: 50 °C {122 °F} or more^*1)

― Vehicle speed: 15 km/h {9.3 mph} or more

― Gear: 3rd gear or more

― Engine speed: 1,000-2,600 rpm

― NOx storage amount: 0.73 g {0.026 oz} or more

• After performing DENOx control, the PCM determines that the control is completed from the λ<1 total time before and after the NSC.

*1 :The engine coolant temperature is expected to fluctuate between 50 °C {122 °F} and 70 °C {158 °F} depending on the ambient temperature.

DESOx control

• When all of the following conditions are met, the PCM performs DESOx control.

DESOx control implementation condition

― Engine warmed up (engine coolant temperature: 50 °C {122 °F} or more^*1)

― Vehicle speed: 15 km/h {9.3 mph} or more

― Gear: 2nd gear or more

― Engine speed: 1,000—2,400 rpm

― During diesel particulate filter regeneration control: The amount of accumulated PM is 7.0 g/L {0.25 lb/ft³}

*1 :The engine coolant temperature is expected to fluctuate between 50 °C {122 °F} and 70 °C {158 °F} depending on the ambient temperature.