Patent ID: 7318427

Claim:
A method for operating an internal combustion engine ( 1 ) having cylinders ( 2 ), each including a piston ( 3 ) delimiting a combustion chamber ( 4 ) to which fuel and fresh gas are supplied to form a combustible fuel mix, the fresh gas being supplied through intake ports ( 13 ) and combustion exhaust gases being discharged through exhaust ports ( 1 ), intake valves ( 6 ) and exhaust valves ( 7 ) disposed in the intake and, respectively, exhaust ports ( 13 , 14 ) for controlling the cyclic charge exchange, and a valve operating mechanism ( 26 ) for operating the valves ( 6 , 7 ) in an operating mode with external ignition, in which the fuel mix is ignited by a spark plug ( 8 ) and which is provided in part of the load range of the internal combustion engine, and an operating mode with compression ignition in which the control of the gas exchange valves ( 6 , 7 ) is altered in such a manner that combustion exhaust gases are retained in the combustion chamber ( 4 ) and participate in the formation of the fresh mix for combustion during the following working cycle of the cylinder ( 2 ) in another part of the load range of the internal combustion engine, said method comprising the step of adjusting, the valve lift of at least one of the gas exchange valves ( 6 , 7 ) during a change in the operating modes, controlling the gas exchange valves ( 6 , 7 ) by means of a cam-type valve operating mechanism ( 26 ), including cams with different cam contours ( 27 ) using a switching element for switching the cams with different contours for changing the operating mode between the external ignition mode and the compression ignition mode, and, in addition to the switch-over between cams, by controlling the start of combustion in the compression ignition mode by changing the gas exchange phases via phase adjustment of the camshaft operating mechanism.