Automotive exhaust muffler assembly technical specification and test methods
1 Scope
This standard specifies the terms and definitions, technical requirements, test methods, inspection rules as well as marking, packaging, transportation and storage of automotive exhaust muffler assembly.
This standard is applicable to exhaust muffler assemblies for Category-M and -N motor vehicles.
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of this standard. For dated references, subsequent amendments (excluding corrections) to, or revisions, of any of these publications do not apply. However, parties to agreements based on this specification are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition applies.
GB/T 3785 Electric, sonic properties and measuring methods for sound level meters
GB/T 3947 Acoustical terminology
GB/T 15089-2001 Classification of power-driven vehicles and trailers
GB/T 15173 Sound calibrators
GB/T 18297-2001 Performance test code for road vehicle engines
3 Terms and definitions
3.1
exhaust system
complete set of device (except exhaust manifold) for treating and discharging exhaust gases produced during engine operation
3.2
exhaust muffler assembly
integral part of the exhaust system that is equipped with sound-absorbing materials or special airflow ducts to effectively reduce the exhaust airflow noise. Single muffler is a muffler component which can independently realize sound absorption function and constitute the exhaust muffler assembly
3.3
leakproofness
degree of air tightness of muffler, expressed by air leakage
3.4
exhaust noise
sound produced when the exhaust gases generated by the engine are discharged from the exhaust pipe orifice
3.5
background noise
noise of the surrounding environment (including wind noise) when the exhaust noise to be measured does not exist
3.6
insertion loss
difference of A weighted sound pressure level of exhaust noise before and after mounting muffler, D, expressed in dB(A). The insertion loss shall be calculated using Formula (1):
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Technical requirements
5 Test methods
6 Inspection rules
7 Marking, packaging, transport and storage
Annex A (Informative) Engine bench test report table of muffler
