Proposal of extensive clarifications to UN R51 by the Informal Group on Additional Sound Emission Provisions (ASEP) in order to provide more consistent and unambiguous specifications for test procedures. Explanations of the proposed changes are provided in document GRB-65-25.

Proposal to delete a description of the L₄ vehicle category (motorcycles with a side car) from Annex 3 to Regulation No. 41. These vehicles fall under the scope of UN R9, having been removed from the scope of UN R41 as of the 04 series of amendments.

Proposal to

1. amend the scope to be design-neutral and reflect the driving situations covered by the Regulation;
2. highlight that ASEP apply to vehicles and their electric sound enhancement systems such as the Audible Vehicle Alert System (AVAS) and silencers equipped with an active cancelling system
3. update the “backfire” assessment procedure; and
4. clarify the gear ratio anchor point in Annex 7 as defined via Annex 3

Modification of the proposal to enable indoor testing under UN R51 on vehicle noise.

1. Paragraph 1: The scope was originally drafted for the Annex 3 test which refers to normal urban driving. A proposed additional sentence covers the intention of Annex 7.
2. Paragraph 2.8.1.: Adopt the wording from standard ISO 362-1:2015 for clarity. If an electric motor is not operational during the type approval tests, then its power must not contribute to the calculation of the power to mass ratio (PMR).

3. Paragraph 2.24., table: Amendments regarding paragraph 2.2.7.4. of Annex 3 because paragraph 2.2.7.4. is new. Amendments also for line BB’ to reflect that the measurement will not end after line BB’. For the speeds vAA’, vBB’ and vPP’, a wrong reference coming from ISO was corrected.

4. Paragraph 2.27.: A new definition of “kickdown” was introduced since this term is used in this Regulation. With a large variety of products, it is unclear what “kickdown” exactly means. This definition is a design neutral approach and reflects the intention of Annex 3 and Annex 7.
5. Paragraph 2.28.: Prevention of downshift is a legal measure to ensure that the vehicle can be tested within the test conditions as specified by this Regulation.
6. Paragraph 3.3.: Deletion of meaningless sentence given the requirement that the vehicles have to be loaded in order to be able to achieve the urban driving conditions as described in paragraph 3.1.2.2. of Annex 3. The sentence has similarly already been deleted in Regulation (EU) No. 540/2014.
7. Paragraph 6.2.3.: The current specification requires a hybrid vehicle to be assessed according to the additional sound emission provisions (ASEP), even though such a vehicle does not have the internal combustion engine running within the control range of Annex 7. There will be no valid test result. Such vehicles should be exempted from ASEP.
8. Annex 1, Appendix 1: For the test method according to 3.1.2.1 the pre-acceleration length may differ per gear ratio. In this case, it is necessary to report the pre-acceleration length per gear ratio.
10. Annex 1, Appendix 2 : Missing elements of the information document have been added, namely “0.2. type” and “3.2.6. pressure charger(s)”.
11. Annex 3, paragraph 2.1.: Lower temperatures will lead to slightly higher test results due to an increased tyre rolling sound. Thus, testing at lower temperatures will be a disadvantage for the manufacturer. If for practical reasons the manufacturer wishes to carry out tests at lower temperatures, this shall be accepted by the type approval authority.
12. Annex 3, paragraph 2.2.1.: For M1 and N1, the current provision has led to ambiguities about its meaning. The proposed new sentence clarifies the meaning. Further, the tolerances are broadened, as research shows, that the impact of the test mass can be neglected in a wide range. For M2, M3, N2 and N3, the current provision has led to ambiguities about its meaning. The proposed new sentence clarifies the meaning. If the test mass of the vehicle is equal to the target mass, the target mass shall be achieved with a tolerance of ±5 per cent according to equation (2) in paragraph 2.2.7.1. of Annex 3. Consequently this has to be valid also for the test mass mt. If the test mass of the vehicle is lower than the target mass according to equation (12) and (13) in paragraph 2.2.7.1. of Annex 3, the test mass shall be achieved with a tolerance of ±5 per cent. Concerning M2 and M3, for clarification and to avoid misunderstanding, the loading conditions for complete vehicles of category M2 (M > 3,500 kg) and M3 were aligned with the requirements for incomplete vehicles of category M2 (M > 3,500 kg) and M3. As a consequence, vehicles of category M2 (M ≤ 3,500 kg) have to be added to the table and their test mass requirement has to be aligned with those of vehicles of category M1 and N1.
13. Annex 3, paragraph 2.2.7.1.: See the above justification for M2, M3, N2 and N3 in paragraph 2.2.1.
14. Annex 3, paragraph 2.2.7.4.: If a manufacturer does not produce vehicles with two axles only, he is not able to calculate the right test mass for his vehicles with more than two axles. For calculating the test mass, a vehicle with two axles has to be put on a scale to measure the unladen front axle load, mfa load unladen, and the unladen rear axle load, mra load unladen, for being able to calculate munladen as given in formula (3) of paragraph 2.2.7.1. of Annex 3. In addition, a new paragraph provides a procedure for calculating the test mass of a virtual vehicles with two axles, based on an existing vehicle with more than two axles, when a vehicle with two axles is physically not available to be put on a scale.
15. Annex 3, paragraph 3.1.2.1.: Proposal to extend the measurement to a position where misfiring is detectable. A redundant sentence is deleted per paragraph 2.2.4.
16. Annex 3, paragraph 1.1.2.1.4.1.(d): Clarify gear usage where one gear ratio is above 2 m/s² and the other below a_urban.
17. Annex 3, paragraph 1.1.2.1.4.1. (e): The suggested changes clarify the proper setup for testing for vehicles with very short gear ratios.
18. Annex 3, paragraph 3.1.2.1.4.3.: Introduction of specifications for vehicles with only one gear ratio.
19. Annex 3, paragraph 3.1.2.1.5. : Simplify testing. With a fixed vehicle length, it is not necessary to adjust the test equipment (light barriers, pylons) for each vehicle.
20. Annex 3, paragraph 3.2.3.: Reference correction
21. Annex 3, paragraph 3.2.5.3.: Reference correction
22. Annex 4, paragraph 1.: The performance of the fibrous material can be checked by completely removing the fibrous material. This reintroduces an option removed when Annex 5 of the 02 series of amendments was revised.


23. Annex 6, paragraph 2.1.: Proposal to simplify and clarify CoP. During the conformity of production procedures, neither the vehicle nor tyres will have a proper preconditioning. In many cases, the vehicles are foiled and parts may be missing as theft protection. It is very unlikely that the vehicles will have already the same performance as the type approval vehicle. This provision adopts the specifications from the revised ASEP provisions (Informal document GRB-65-26, Annex 7, para. 1). In addition, the range of masses was broadened in the same way as proposed for type approval.
24. Annex 6, paragraph 3.: Reference correction.

Proposal including indoor testing as an alternative to type approval tests of Annex 3 to Regulation No. 51 including ISO 362-3.

Proposal to align the transitional provisions in the 01 series of amendments with the format introduced following Revision 3 of the 1958 Agreement.

Measurement Setup Scheme for Stationary Sound Emission Test – Engine Proximity: Stationary Run-Up Measurement (SLOW run-up) from IDLE to Govern Engine Speed