Patent ID: 7815128

Claim:
A method for injecting a fluid comprising the steps of: providing at least one nozzle which can be actuated by means of a piezo element for an injection process including a pre-injection and a main injection, and during the pre-injection: supplying a current pulse to the piezo element, recording the capacity of the piezo element when the current pulse is supplied, recording an actual characteristic curve of the pre-injection based on the capacity, determining, based on the actual characteristic curve of the pre-injection, at least one of (a) an actual start of the pre-injection, (b) an actual end of the pre-injection, and (c) an actual duration of the pre-injection, determining one or more difference values for at least one of (a) a difference between a predefined start of the pre-injection and the actual start of the pre-injection, (b) a difference between a predefined end of the pre-injection and the actual end of the pre-injection, and (c) a difference between a predefined duration of the pre-injection and the actual duration of the pre-injection, based on the one or more difference values, determining one or more correction values for at least one of (a) an injection start time for the main injection, (b) an injection end time for the main injection, and (c) an injection period for the main injection, and adjusting a further current pulse for the main injection based on the one or more correction values.