Patent ID: 7280950

Claim:
A method for fabrication of a diesel engine turbocharger turbine stage, comprising the steps of: selecting a set of discrete throttle settings for the engine, wherein the selected discrete throttle settings correlate to discrete rotational speeds of the turbocharger; modeling the turbocharger for the engine, including modeling of the turbine stage thereof for vibration analysis, said modeling of the turbine stage further comprising modeling of turbine blades of a turbine wheel and modeling turbine nozzle vanes; determining one or more natural frequencies of vibration of the turbine blades for each of the throttle settings; determining a turbine nozzle vane induced turbine blade excitation frequency as a function of the turbocharger rotational speed at that throttle setting; and ascertaining whether a data coincidence is present at each of the throttle settings, said step of ascertaining comprising determining whether, at the rotational speed corresponding to that throttle setting, there is a data coincidence of said one or more natural frequencies of vibration and said turbine nozzle vane induced turbine blade excitation frequency; wherein if there is an absence of said data coincidence at each of the throttle settings, the turbine stage fabricated according to said step of ascertaining will have turbine blades which are at least substantially free of harmonically resonant vibrations at the discrete rotational speeds of the turbocharger.