Document ID: chunk:federal_register_of_legislation:F2024L00446:reg:23:p10
Version: federal_register_of_legislation:F2024L00446
Segment Type: reg
Provision Reference: reg 23 (pt 10/15)
Character Range: 1924320–1927346

equal to zero.
These additive deterioration factors shall follow the same rules described for the multiplicative deterioration factors in relation to Level 1A (4 phase WLTP) and Level 1B (3 phase WLTP).
Annex C4 - Appendix 1

Standard Bench Cycle (SBC)
This appendix applies to Level 1A only
1. Introduction
 The standard ageing durability procedure consists of ageing a catalyst/oxygen and/or air fuel ratio sensor system on an ageing bench which follows the Standard Bench Cycle (SBC) described in this appendix. The SBC requires the use of an ageing bench with an engine as the source of feed gas for the catalyst. The SBC is a 60-second cycle which is repeated as necessary on the ageing bench to conduct ageing for the required period of time. The SBC is defined based on the catalyst temperature, engine air/fuel (A/F) ratio, and the amount of secondary air injection which is added in front of the first catalyst.
2. Catalyst temperature control
2.1. Catalyst temperature shall be measured in the catalyst bed at the location where the highest temperature occurs in the hottest catalyst. Alternatively, the feed gas temperature may be measured and converted to catalyst bed temperature using a linear transform calculated from correlation data collected on the catalyst design and ageing bench to be used in the ageing process.
2.2. Control the catalyst temperature at stoichiometric operation (01 to 40 seconds on the cycle) to a minimum of 800 °C (±10 °C) by selecting the appropriate engine speed, load, and spark timing for the engine. Control the maximum catalyst temperature that occurs during the cycle to 890 °C (±10 °C) by selecting the appropriate A/F ratio of the engine during the "rich" phase described in Table C4 App1/2.
2.3. If a low control temperature other than 800 °C is utilized, the high control temperature shall be 90 °C higher than the low control temperature.
       Table C4 App1/2
       Standard Bench Cycle (SBC)

Time
(seconds)  Engine air/fuel ratio                                                                                                                                 Secondary air injection
1-40       Stoichiometric with load, spark timing and engine speed controlled to achieve a minimum catalyst temperature of 800 °C                                None

41-45      "Rich" (A/F ratio selected to achieve a maximum catalyst temperature over the entire cycle of 890 °C or 90 °C higher than lower control temperature)  None

46-55      "Rich" (A/F ratio selected to achieve a maximum catalyst temperature over the entire cycle of 890 °C or 90 °C higher than lower control temperature)  3 % (±1 %)

56-60      Stoichiometric with load, spark timing and engine speed controlled to achieve a minimum catalyst temperature of 800 °C                                3 % (±1 %)

              Figure C4 App1/2
              Standard Bench Cycle
              3. Ageing bench equipment and procedures
              3.1. Ageing bench configuration. The ageing bench shall provide the