SAE J1492_202311

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 or simulated exhaust sound level over a range of engine speeds or simulated engine speeds. This document applies only to road vehicles equipped with an internal combustion engine or with an external sound system. 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. SAE J2805 provides methods to assess vehicle noise emission consistent with in-use vehicle noise emissions at realistic vehicle loads and speeds. This document incorporates certain provisions of ISO 5130:2019 for measuring the sound level of exhaust systems (see Appendix A). SAE J1492 is updated to include testing of all modes and to clarify procedure applies to all propulsion technologies. This SAE Recommended Practice is designed to check vehicle exhaust noise or simulated exhaust noise against a reference value. However, it has been used by some jurisdictions to support checking against a fixed limit value. This version of SAE J1492 incorporates provisions where the standard may be used by authorities to check against a fixed limit. This recommended practice also incorporates provisions for additional exhaust system configurations and the use of vehicles with driver selectable modes.