Method and device for determining a vibration-optimised adjustment of an injection device

A method of determining a vibration-optimized adjustment of an injection device of an internal combustion engine, the method comprising:

• providing for a specific engine adjustment by the injection device for each cycle of the internal combustion engine a plurality of at least two individual injections per cylinder, each of which is defined at least by a relative injection instant and an individual injection quantity,
• wherein a time characteristic of a resulting pressure that is influenced by pressure waves caused by the individual injections is determined in a fuel-carrying part of the injection device, wherein said adjustment is determined by varying the injection instant of at least one of:
• at least one individual injection and an individual injection quantity of at least one individual injection in such a way that this adjustment is characterized by a reduced temporal fluctuation of the resulting pressure as a result of interferences between said pressure waves;
• wherein said adjustment is determined as meeting at least one of the following criteria:
• a greatest amplitude of a resulting pressure fluctuation of the resulting pressure at least one of:
• assumes an absolute or relative minimum and falls below a defined threshold,
• a greatest amplitude of frequency components of the resulting pressure fluctuation that fall into a defined frequency band at least one of:
• assumes an absolute or relative minimum and falls below a defined threshold,
• a squared amplitude of the resulting pressure fluctuation that is integrated over a defined part of a cycle at least one of:
• assumes an absolute or relative minimum and falls below a defined threshold, and
• a squared amplitude of frequency components of the resulting pressure fluctuation that is integrated over a defined frequency band at least one of assumes an absolute or relative minimum and falls below a defined threshold.