Upcoming changes to ISO 362 - Exterior Noise test procedure (passby) by Doug Moore

ISO Technical Committee 43, Subcommittee 1 Noise,� Workgroup 42 has developed a revision to the ISO 362 standard used globally for the evaluation of exterior motor vehicle noise, commonly referred to as Passby.� This standard is presently being circulated at the Draft International Standard (DIS) level for comment and voting by the member bodies of ISO. The ISO 362DIS has also been incorporated in a proposed revision to Economic Commission for Europe (ECE) regulation 51 on motor vehicle noise. ECE R51 is used directly or indirectly in all markets outside of North America. In North America, ISO 362 is presently mirrored as SAE J1470 which is used to certify compliance to exterior noise regulations in the US, Canada and Mexico for light duty vehicles.

The 362DIS standard incorporates a number of evolutionary technical changes from the current standard. It also explicitly specifies performance criteria, instead of design specific criteria, as the relevant parameters to perform the test. The changes are summarized as follows:

1) The 362DIS seeks to estimate noise emission of a vehicle consistent with urban driving. The method seeks to approximate the real world part throttle operation of light duty vehicles.

2) All relevant vehicle noise sources shall be included in the measurement. This means that tire/road noise is now included in the measurement.

3) To accomplish the estimate of partial throttle operation, the measurement now uses both a WOT acceleration and a 50 km/hr cruise condition. The WOT acceleration must meet a specified acceleration target that is a function of the vehicle