Document ID: chunk:federal_register_of_legislation:F2024L00446:reg:16:p103
Version: federal_register_of_legislation:F2024L00446
Segment Type: reg
Provision Reference: reg 16 (pt 103/108)
Character Range: 1179784–1182533

in the case of the worstcase approach, in accordance with paragraph 4.1 of this Annex B6a.

              3.9. Provision for cool down

              3.9.1. For the test vehicle serving as a reference vehicle for the ATCT Family and all vehicles H of the interpolation families within the ATCT Family, the end temperature of the engine coolant shall be measured after soaking at 23 °C for the duration of tsoak_ATCT, with a tolerance of an additional 15 minutes, having beforehand driven the respective Type 1 test at 23 °C. The duration is measured from the end of that respective Type 1 test.

              3.9.1.1. In the case that tsoak_ATCT was extended in the respective ATCT test, the same soaking time shall be used, with a tolerance of an additional 15 minutes.

              3.9.2. The cool down procedure shall be undertaken as soon as possible after the end of the Type 1 test, with a maximum delay of 20 minutes. The measured soaking time is the time between the measurement of the end temperature and the end of the Type 1 test at 23 °C, and shall be included in all relevant test sheets.

              3.9.3. The average temperature of the soak area of the last 3 hours shall be subtracted from the measured temperature of the engine coolant at the end of the soaking time specified in paragraph 3.9.1. This is referred to as ∆T_ATCT, rounded to the nearest whole number.

              3.9.4. If ∆T_ATCT is higher or equal than -2 °C from the test vehicle ∆T_ATCT, this Interpolation Family shall be considered to be a member of the same ATCT Family.

              3.9.5. For all vehicles within an ATCT Family the coolant shall be measured at the same location in the cooling system. That location shall be as close as possible to the engine so that the coolant temperature is as representative as possible to the engine temperature.

              3.9.6. The measurement of the temperature of the soak areas shall be as specified in paragraph 3.2.2.2. of this Annex B6a.

              4. Alternatives in the measurement process

              4.1. Worst case approach vehicle cool down or with regards to vehicle insulation

              On request by the manufacturer and with approval by the approval authority, the Type 1 test procedure for cool down may be applied instead of provisions of paragraph 3.6 of this Annex B6a. For that purpose:

                  (a) The provisions of paragraph 2.7.2. of Annex B6 shall apply with the additional requirement of a minimum soak time of 9 hours.

                  (b) The engine temperature shall be within ± 2 °C of the set point Treg before the start of the ATCT test. That temperature shall be included in all relevant test sheets. In this case, the provision for cool down