Document ID: chunk:federal_register_of_legislation:F2023L00129:reg:10:p145
Version: federal_register_of_legislation:F2023L00129
Segment Type: reg
Provision Reference: reg 10 (pt 145/150)
Character Range: 1129250–1132265

steps set out in paragraphs 2.4.2.10.3. and 2.4.2.10.4. shall be repeated until the NTS values obtained for each device in the system match.

              2.4.2.10.6. The Tr values used for obtaining the different NTS in paragraphs 2.4.2.10.4. and 2.4.2.10.5. shall be the same ones as those used in paragraphs 2.3.2. and 2.3.5. for calculating AT for each device.

              2.4.2.11. In the case of an assembly of replacement pollution control devices constituting a system which is to be approved as a separate technical unit, one of the following two options may be considered for the thermal ageing of the devices:

              2.4.2.11.1. The devices within the assembly may be either separately or jointly aged, in accordance with paragraph 2.4.2.10.

              2.4.2.11.2. If the assembly is built in such a way that it is not possible to decouple the devices (e.g. DOC + SCR in a can), the thermal ageing of the assembly shall be carried out with the highest NTS.

              2.4.3. Modified thermal accumulation schedule for devices operating in the presence of active regeneration

              2.4.3.1. The modified thermal accumulation schedule for devices operating in the presence of active regeneration shall simulate the effect of ageing due to both thermal load and active regeneration on a replacement pollution control device at the end of its lifetime.

              2.4.3.2. The engine used for the service accumulation schedule, fitted with the exhaust after-treatment system incorporating the replacement pollution control device, is operated for a minimum of three modified thermal sequences, consisting each sequence of a thermal sequence as set out in Appendix 5, followed by a complete active regeneration, during which the peak temperature reached in the after-treatment system should be not lower than the peak temperature recorded in the data collection phase.

              2.4.3.3. The temperatures shall be recorded over a minimum of two modified thermal sequences. The first sequence, conducted for warming up, shall not be taken into account for the purpose of temperature gathering.

              2.4.3.4. In order to minimize the time elapsed between the thermal sequence as set out in Appendix 5 and the subsequent active regeneration, the manufacturer may artificially trigger the active regeneration by running, after each thermal sequence as set out in Appendix 5, the engine at a steady mode that enables a high production of soot by the engine. In that case, the steady mode shall also be considered as part of the modified thermal sequence set out in paragraph 2.4.3.2.

              2.4.3.5. The effective ageing time corresponding to each modified thermal sequence shall be calculated using equations 3 and 4.

              2.4.3.6. The total number of modified thermal sequences to be conducted during the service accumulation schedule shall be calculated using equation 5.

              2.4.3.7. It is allowed to reduce NTS, and consequently the