Patent ID: 7258109

Claim:
A method for operating a fuel injection device, comprising: activating a piezoelectric element of an injection valve in such a way that the injection valve goes over into an opened state, wherein the injection valve injects fuel directly into a combustion chamber; at least one of (a) at least one of ascertaining and prespecifying an electrical voltage at the piezoelectric element and (b) at least one of ascertaining and specifying an electrical current via the piezoelectric element, during the activation; inferring a point in time of opening of the injection valve as a function of a path of at least one of the voltage and the current, wherein the voltage is prespecified and the current is ascertained, and from the path of the current a point in time of opening of the injection valve is inferred; checking the current to determine whether the current remains unequal to zero directly after the voltage is reached which is required to bring the injection valve into the opened state; and establishing a possible malfunction of the injection valve provided, directly after the voltage is reached which is required to bring the injection valve into the opened state, the current approaches zero.