The present invention relates to an internal combustion engine for motor
vehicles. The engine can be operated in homogeneous charge compression
ignition (HCCI) combustion mode and in conventional spark ignited (SI)
combustion mode. For increasing volumetric efficiency and charge
temperature during homogeneous charge compression ignition combustion
operation timing, duration and lift of the intake valve and the exhaust
valve respectively, being controlled such that an amount of residual
exhaust gases is trapped in the cylinder of the engine. An intake valve
is opened at a timed moment after top dead center during an induction
stroke of the piston such that a pressure wave is generated from an
intake manifold into the cylinder. The intake valve is closed at a timed
moment before the pressure wave is reflected within the cylinder such
that a charge mass of said pressure wave is retained within the cylinder.