Originally Posted by MtViewGuy88
I think the thing that will could make HCCI actually work at all speed ranges is the possibility of improved variable-timing valvetrain operation (the next-generation i-VTEC?), which will allow
extreme precision in air-fuel mixture control so the compression-ignition process to work throughout the rev range. If Honda succeeds, we maybe talking 30% better fuel economy regardless of engine; that means the current 3.5-liter V-6 engine could get at least 6 mpg improvement in the EPA city cycle!

Or the Honda Civic getting 39 mpg in the EPA city cycle....
BMW already has an all speed range (rpm range) variable timing valvetrain.