Patent ID: 7712440

Claim:
An internal combustion engine operable in homogeneous charge compression ignition combustion mode and in conventional spark ignited combustion mode provided with at least one cylinder and comprising: an intake manifold; fuel injecting means, for injecting fuel into a combustion chamber, of each cylinder; fuel injection control means, for controlling fuel injection quantity per combustion cycle injected using each said fuel injecting means; a piston, arranged for reciprocating action within said cylinder; at least one intake valve for admitting oxygen containing gas from said intake manifold into said cylinder; at least one exhaust valve for exhausting combusted gases from said cylinder; means for controlling timing, duration and lift of said intake valve and said exhaust valve respectively; and characterized in that for increasing volumetric efficiency and charge temperature during homogeneous charge compression ignition combustion operation, said means for controlling timing, duration and lift of said intake valve and said exhaust valve respectively being arranged to operate such that an amount of residual exhaust gases is trapped in said cylinder; said intake valve is arranged to be opened at a timed moment after top dead centre during an induction stroke of said piston such that a pressure wave is generated from said intake manifold into said cylinder, and said intake valve is arranged to be closed at a timed moment before said pressure wave is reflected within said cylinder such that a charge mass of said pressure wave is retained within said cylinder.