For many years, measuring fuel injector nozzles has been part of the standard repertoire at Werth Messtechnik GmbH. Typically, the injector hole diameters of just a few tenths of a millimeter are measured using VideoCheck multisensor coordinate measuring machines with rotary/tilt axes and Werth Fiber Probe. Today nearly all manufacturers of injection systems for gasoline and diesel engines around the world use this technology, by Werth.

Increasingly, TomoScope coordinate measuring machines with computed tomography are used for this measurement task. Computed tomography provides a comprehensive point cloud of the complete work piece. Areas in the interior of the nozzle that are difficult to access can be measured easily. The wall thickness and pressure-side volume can be determined completely and non-destructively in a single setup without false castings. Fixturing is also economical, because difficult to access datum points can be measured directly and need not to be defined by the fixture. The low measurement uncertainties required for determining the hole diameters, in the sub-micrometer range, are achieved by correcting the absolute values using the Werth Auto-Correction process. The measured values are thus traceable through reference measurements with the Werth Fiber Probe.

The new Werth Nozzle Module, developed from years of experience, has greatly simplified the measurement. Complete para-meterization allows measurement of a large number of different types of nozzles without any user programming. With just a few entries, measurement and analysis of diesel and gasoline injector nozzles are performed automatically. This software solution can be used with the full range of VideoCheck machines with image processing and fiber probe, or TomoScope machines with X-ray tomography sensors.