I just heard about something called Variable Cylinder Management by Honda where the computer can take a V6 engine and make it run on three Cylinders while cruisng and then utilize all 6 cylinders when accelerating or when high power output is desired
http://www.motortrend.com/features/auto_news/news_030618_hon/index.html
http://www.motortrend.com/features/auto_news/news_030618_hon/index.html