SAE J1492_200810

This SAE Recommended Practice establishes the test procedure, environment, and instrumentation to be used for measuring the exterior exhaust sound level for passenger cars, multipurpose vehicles, and light trucks under stationary conditions providing a continuous measure of exhaust system sound level over a range of engine speeds. This document applies only to road vehicles equipped with an internal combustion engine. The method is designed to meet the requirements of simplicity as far as they are consistent with reproducibility of results under the operating conditions of the vehicle. It is within the scope of this document to measure the stationary A-weighted sound pressure level during: measurements at the manufacturing stage measurements at official testing stations measurements at roadside testing It does neither specify a method to check the exhaust sound pressure level when the engine is operated at realistic load nor a method to check the exhaust sound pressure levels against a general noise limit for categories of road vehicles. It provides the means for detecting exhaust system resonances with the potential to affect both exterior and interior sound quality. This document incorporates certain provisions of ISO 5130:2007 for measuring the sound level of exhaust systems. (See Appendix A.) Prior SAE Standards assumed vehicles could be operated at ¾ rated engine speed for the purpose of stationary sound pressure level testing. Technical development of vehicles and engines have changed the operation of many engines and vehicles under stationary conditions. This standard incorporates the changes in exhaust system configuration and the use of engine management and fuel cut-off systems during stationary conditions.