Method for determining the idle travel of a piezo-injector with a directly actuated nozzle needle

摘要

A method is disclosed for determining the idle travel of a piezo-injector which has a piezo-actuator and a nozzle needle which is activated directly by the piezo-actuator. A test pulse is applied to the piezo-actuator, which pulse brings about a continuous increase in the piezo-travel. The time period is measured which passes between the starting of the test pulse and the time when the idle travel is overcome. The idle travel of the piezo-injector is then determined from the measured time period.

主权项

1. A method for determining an idle travel of a piezo-injector that comprises a piezo-actuator and a nozzle needle actuated by the piezo-actuator, the method comprising:
applying a test pulse to the piezo-actuator that produces a continuous increase of a piezo stroke of the piezo-actuator, wherein the magnitude of the test pulse does not produce a needle stroke within a predefined duration of the test pulse; wherein the test pulse comprises application of a constant value of current; measuring the time period that passes between a commencement of the test pulse and a point at which the idle travel is overcome and the piezo-actuator impacts the pin, and determining the idle travel of the piezo-injector based on the measured time period.