A method of transitioning a cylinder of an engine from a spark ignition
mode to a homogeneous charge compression ignition mode, the cylinder
having at least one electrically actuated intake valve and at least one
exhaust valve, the method comprising of before a transition, operating
the cylinder with at least some overlap between an opening event of the
intake valve and an opening event of the exhaust valve in the spark
ignition mode; in response to a transition request, operating the
cylinder with at least some negative overlap between an opening event of
the intake valve and an opening event of the exhaust valve, retarding the
intake valve opening and closing timing by different amounts and
retarding ignition timing; and further increasing negative overlap and
performing the homogeneous charge compression ignition mode.