The present disclosure relates to a system for controlling ignition of an intake charge directed into an internal combustion engine. The system may have a movable component operably associated with at least one of a piston of the engine or a combustion chamber of the engine. The movable component may be tuned to deflect in response to a predetermined pressure being reached in a cylinder in which the piston is housed. The movable component operates to deflect in response to the predetermined pressure being reached in the cylinder as the piston travels toward top dead center during its compression stroke, to change a compression ratio of the engine.

The present disclosure relates to a system for controlling ignition of an intake charge directed into an internal combustion engine. The system may have a movable component operably associated with at least one of a piston of the engine or a combustion chamber of the engine. The movable component may be tuned to deflect in response to a predetermined pressure being reached in a cylinder in which the piston is housed. The movable component operates to deflect in response to the predetermined pressure being reached in the cylinder as the piston travels toward top dead center during its compression stroke, to change a compression ratio of the engine.

A method and device for determining a value for a valve lift of a valve of an individual cylinder of a multi-cylinder internal combustion engine are provided. The method includes determining a first exhaust-gas lambda value for fuel combustion in the individual cylinder in a first operating state of the engine by a cylinder-individual and time-resolved detection of lambda values without an artificial variation in an air/fuel ratio. The method also includes determining an air mass sucked in by all cylinders of the engine in the first operating state. The method also includes determining the value for the valve lift of the valve of the individual cylinder based on the first exhaust-gas lambda value, the determined air mass, and a correction value, wherein the correction value is based on a relationship between the valve lift and an associated air mass sucked in by all cylinders of the engine.