Abstract: In a method for operating a four-stroke internal combustion engine with a homogeneous, lean basic mixture of air and fuel and with compression ignition, the fuel/air ratio formed in the combustion space is variable by means of a controllable inlet member. In order to achieve as rapid adaptation as possible to varied combustion sequences, a measurement of the respective combustion is carried out and the time of closing of the inlet member of the combustion space is regulated, for a next successive cycle, as a function of the signal obtained from this measurement.

Abstract: In a method for the operation of a four-stroke reciprocating piston internal combustion engine with alternating compression. ignition and spark ignition, fuel is injected directly, fresh charge is delivered and combustion exhaust gas is led off. At low and medium partial load a partially homogenized, lean basic mixture of air, fuel and retained exhaust gas is formed for the compression ignition, and at higher partial load and at full load a homogeneous, stoichiometric mixture is formed for the spark ignition. Further features include exhaust gas retention, a build-up of exhaust gas and activation injection into the retained exhaust gas. For a smooth transition between the two operating modes, in addition to the co-ordinated interaction of exhaust gas retention, build up of exhaust gas, restriction of the fresh charge, and of the ignition advance angle in spark ignition, together with the quantity and the timing of the fuel injection, use is also made of exhaust gas recirculation.

Abstract: In a method for operating a four-stroke internal combustion engine, a homogeneous lean basic mixture of air and fuel is ignited by compression ignition. The fuel is introduced by direct fuel injection into a combustion space delimited by a cylinder with a piston guided sealingly therein. In the case of homogeneous mixture formation, due to the supply of energy as a result of compression a homogeneous ignition performance is established, and pronounced self-accelerating energy release takes place as a result.

Abstract: A method for operating a four-stroke internal combustion engine which allows the combustion-chamber pressure to be equalized in a cylinder-selective manner consistent with the cycle, in which the quantity of exhaust gas retained with valve closure overlap selected is controlled or preset as a function of the engine speed and load by an exhaust throttle valve affecting all the combustion chambers, and the pressure in the individual combustion chambers when the inlet members are opened is equalized by corresponding cylinder-selective activating injection in a manner consistent with the cycle.