"In addition to low fuel consumption, the VCM engine also reduces exhaust emissions, helping meet govt Ultra-Low Emissions and 2010 fuel consumption standards, making it eligible for preferential 'Green Tax' treatment. The engine achieves this by combining high-density catalytic converters located directly below each cylinder head for further improved exhaust gas processing at low engine temperatures with better air/fuel ratio control.
VCM continuously analyzes throttle opening, vehicle speed, engine speed, and gearing to determine that the car is cruising, and then idles the intake and exhaust valves of the three cylinders in the rear cylinder bank. With zero valve lift, the cylinders are sealed, and no fuel is injected. Pumping losses are thus reduced by as much as 65% and low fuel consumption is realized.
When operating in 3-cylinder mode, engine vibration is reduced by extrapolating vibration from the change in crankshaft rotation speed and sending the information to the 'active control' engine mount, which compresses/extends an actuator in same-phase, same-period motion to dampen the engine mount. Similarly, a speaker creates an opposite phase sound or 'active noise control', to provide a cancelling effect, for a quieter interior which leaves the driver unaware of changes in cylinder activation."
Just don't know how it feels to the driver when activation/deactivation kicks in. Perhaps I could use a day to test drive a VCM 643-powered Honda? (Hint, hint.)