Abstract: A method for operation of a direct-injection spark-ignition internal combustion engine operated over large areas of the characteristics map with stratified charge by way of fuel injection during the compression stroke. In order to guarantee reliable mixture ignition and combustion, the method of the present invention provides an ignition system which generates alternating voltage so that high voltage rapidly builds up between the electrodes of a spark plug, and generates ignition sparks with a spark duration that can be defined as a function of operating point.

Abstract: A changeover is made between a so-called low-pressure starting with a homogeneous mixture and a so-called high-pressure starting with a stratified mixture as a function of an engine coolant temperature. Since, during the high-pressure starting of the internal combustion engine, injection is released only when a pressure in a high-pressure accumulator exceeds a predetermined threshold value, the injected fuel is better prepared. During such high-pressure starting, injection is predetermined by an injection quantity and an angle of an end of injection. Predetermining the angle of the end of injection, in contrast to predetermining an angle of commencement of injection during conventional low-pressure starting, ensures that there is an ignitable mixture present at the sparkplug, specifically irrespective of a duration of injection.

Abstract: Otto internal-combustion engines having one injector respectively per cylinder for the internal mixture formation can be operated at full load or high partial load by fuel injection in the suction stroke of the piston and, at medium or low partial load, with a compression stroke injection. The compression stroke injection, which is advantageous in this load range, because of low average combustion space temperatures and the tendency to form deposits in the combustion space because of residues of liquid fuel and the resulting impaired operating conditions, can partially be carried out only to a limited degree.

Abstract: In a method of controlling adjustable operating parameters of an internal combustion engine with direct fuel injection which includes at least one cylinder having a piston delimiting a combustion chamber, a fuel injector and a spark plug, wherein air supplied to the combustion chamber through an air intake passage forms with the fuel injected by the fuel injector a fuel/air mixture which is compressed and produces a plasma cloud which is then ignited by a spark generated between the electrodes of the spark plug, the ionization degree of the plasma cloud is measured and an ionization signal is formed and supplied to an electronic control unit where it is utilized to control at least one operating parameter of the internal combustion engine.