Document ID: chunk:federal_register_of_legislation:F2024L00446:reg:23:p5
Version: federal_register_of_legislation:F2024L00446
Segment Type: reg
Provision Reference: reg 23 (pt 5/15)
Character Range: 1910407–1913446

the BAT equation. The SBC is described in Appendix 1 to this annex.

              2.3.1.3. Catalyst time-at-temperature data

               Catalyst temperature shall be measured during at least two full cycles of the SRC cycle as described in Appendix 3 to this annex.

                Catalyst temperature shall be measured at the highest temperature location in the hottest catalyst on the test vehicle. Alternatively, the temperature may be measured at another location providing that it is adjusted to represent the temperature measured at the hottest location using good engineering judgement.

                Catalyst temperature shall be measured at a minimum rate of one hertz (one measurement per second).

                The measured catalyst temperature results shall be tabulated into a histogram with temperature groups of no larger than 25 °C.

              2.3.1.4. The Bench Ageing Time (BAT) shall be calculated using the BAT equation as follows:

                te for a temperature bin = th e((R/Tr)-(R/Tv))

                Total te = Sum of te over all the temperature groups

                Bench Ageing Time = A × (Total te)

 Where:

 A             = 1.1  This value adjusts the catalyst ageing time to account for deterioration from sources other than thermal ageing of the catalyst.

 R             =      Catalyst thermal reactivity = 17,500

 th            =      The time (in hours) measured within the prescribed temperature bin of the vehicle's catalyst temperature histogram adjusted to a full useful life basis e.g., if the histogram represented 400 km, and useful life is 160,000 km; all histogram time entries would be multiplied by 400 (160,000/400).

 Total te      =      The equivalent time (in hours) to age the catalyst at the temperature of Tr on the catalyst ageing bench using the catalyst ageing cycle to produce the same amount of deterioration experienced by the catalyst due to thermal deactivation over the 160,000 km.

 te for a bin  =      The equivalent time (in hours) to age the catalyst at the temperature of Tr on the catalyst ageing bench using the catalyst ageing cycle to produce the same amount of deterioration experienced by the catalyst due to thermal deactivation at the temperature bin of Tv over 160,000 km.

 Tr            =      The effective reference temperature (in K) of the catalyst on the catalyst bench run on the bench ageing cycle. The effective temperature is the constant temperature that would result in the same amount of ageing as the various temperatures experienced during the bench ageing cycle.

 Tv            =      The mid-point temperature (in K) of the temperature bin of the vehicle on-road catalyst temperature histogram.

2.3.1.5. Effective reference temperature on the SBC. The effective reference temperature of the SBC shall be determined for the actual catalyst system design and actual ageing bench which will be used using the following procedures:
                  (a) Measure time-at-temperature data in the catalyst system on