Impact of Cylinder Deactivation Strategies on Three-way Catalyst Performance in High Efficiency Low Emissions Engines

Reduction of CO2 emissions is a prevalent subject in the transportation sector. Cylinder deactivation (CDA) provides a method to reduce CO2 emissions at part load. However, there is little consideration of how these strategies affect catalyst performance.

Effects of two CDA strategies on catalyst performance were studied. The first strategy of open-loop lambda control CDA improved catalyst CO conversion to 100 % and prevented NH3 formation over the catalyst. There was a NOX penalty if the duration exceeded 5 seconds. The closed-loop CDA strategy increased catalyst temperature by 300°C for durations of 60 seconds.

Open-loop CDA can prevent NH3 formation and improve CO conversion. Closed-loop CDA strategy has potential to increase catalyst temperature and be effective at reducing light-off during cold starts without additional hardware. This gives the strategy an advantage over more complex heating options. Both strategies provide opportunities to help meet current and future emission regulations.