Powerplant sound pressure level (SPL) target setting is the first critical step to develop an efficient NVH (Noise, Vibration, Harshness) strategy that guides computer aided analysis and hardware research to achieve a desired goal in the early stage of a vehicle development program. For many years, engineers have been trying to find a simple and economic method to cascade NVH targets to the component level quantitatively. This has been difficult since no single measurement method can achieve this goal. Traditionally, specifications have been set by comparison of a baseline powerplant SPL average of several measurement locations with its target, but it does not cascade SPL to individual component contributions. Only a sound pressure level average of all microphones at a desired RPM range has been used in target setting processes. This method can no longer meet current NVH development demands. Without an explicit NVH target for individual components, it has been difficult to deploy an adequate strategy for NVH design or improvement. Furthermore, the traditional method requires physical test data from both baseline and target powerplants. Therefore, it does not work for a new powerplant design. By combining sound pressure level and sound source ranking test data of a baseline powerplant, one can cascade a target to its component level at desired frequencies quantitatively. This ensures that resources will be spent on the right components that affect SPL the most. The cascading can be done by comparing individual SPL measurements and frequency content of a baseline powerplant with its target, then reducing the component power level in a manner that the highest power component gets the most reduction at the desired frequency range. There are two critical steps in this new method. First, identify component contributions to individual measurement locations - some components may contribute sound power energy to more than one measurement location. Then, find the workable frequency range for each individual baseline component. The workable frequency range is the common dominant frequency range and the frequency range of interest. Any modifications outside this common range may not be effective for NVH improvement. Second, assign PWL (sound power level) reductions to individual components. Usually the component with the highest PWL should get the most reduction and have the highest priority for NVH improvement. Next, calculate the overall PWL reduction for each measurement location. Repeat this process until the target is met. The total reduction of PWL should equal the required reduction of SPL.


    Access

    Access via TIB

    Check availability in my library

    Order at Subito €


    Export, share and cite



    Title :

    Target setting procedures for vehicle powerplant noise reduction


    Additional title:

    Identifikation und Beseitigung von Geräuschquellen in Kraftfahrzeugen


    Contributors:
    Zeng, P.W. (author)

    Published in:

    Sound and Vibration ; 37 , 7 ; 20-23


    Publication date :

    2003


    Size :

    4 Seiten, 4 Bilder, 1 Tabelle, 6 Quellen



    Type of media :

    Article (Journal)


    Type of material :

    Print


    Language :

    English




    Cures for Powerplant Bending Noise Problems

    Ruhl, J.H. / Bollinger, R.H. | SAE Technical Papers | 1961


    Powerplant

    Emerald Group Publishing | 1971


    Powerplant

    Emerald Group Publishing | 1969


    Powerplant

    Emerald Group Publishing | 1974


    Noise source identification in an automotive powerplant

    Raveendra,S.T. / Sureshkumar,S. / Cheng,M.T. et al. | Automotive engineering | 2003