Document ID: chunk:federal_register_of_legislation:F2023L00129:reg:13:p23
Version: federal_register_of_legislation:F2023L00129
Segment Type: reg
Provision Reference: reg 13 (pt 23/27)
Character Range: 700834–703945

permitted.
              3.5.2. The emission values for each pollutant at the start of the service accumulation schedule and at the useful life end point that is applicable for the engine under test shall be calculated from the regression equation. If the service accumulation schedule is shorter than the useful life period, the emission values at the useful life end point shall be determined by extrapolation of the regression equation as determined in paragraph 3.5.1.
              3.5.3. The deterioration factor for each pollutant is defined as the ratio of the applied emission values at the useful life end point and at the start of the service accumulation schedule (multiplicative deterioration factor).
               At the request of the manufacturer and with the prior approval of the Type Approval Authority, an additive deterioration factor for each pollutant may be applied. The additive deterioration factor shall be considered as the difference between the calculated emission values at the useful life end point and at the start of the service accumulation schedule.
               If the calculation results in a value of less than 1.00 for a multiplicative DF, or less than 0.00 for an additive DF, then the deterioration factor shall be 1.0 or 0.00, respectively.
               An example for determination of deterioration factors by using linear regression is shown in Figure 1.
               Mixing of multiplicative and additive deterioration factors within one set of pollutants shall not be permitted.
               In accordance with paragraph 3.2.1.4., if it has been agreed that only one test cycle (hot WHTC or WHSC) be run at each test point and the other test cycle (hot WHTC or WHSC) run only at the beginning and end of the service accumulation schedule, the deterioration factor calculated for the test cycle that has been run at each test point shall be applicable also for the other test cycle.
           Figure 1
           Example of deterioration factor determination
              3.6. Assigned deterioration factors
              3.6.1. As an alternative to using a service accumulation schedule to determine deterioration factors, engine manufacturers may choose to use the following assigned multiplicative deterioration factors:
       Table 2
       Deterioration factors
Test cycle  CO   THC1  NMHC2  CH42  NOx   NH3  PM mass  PM number
WHTC        1.3  1.3   1.4    1.4   1.15  1.0  1.05     1.0
WHSC        1.3  1.3   1.4    1.4   1.15  1.0  1.05     1.0

              Notes:
 1  Applies in case of a compression ignition engine.
 2 Applies in case of a positive ignition engine.

               Assigned additive deterioration factors are not given. It shall not be permitted to transform the assigned multiplicative deterioration factors into additive deterioration factors.
              3.7. Application of deterioration factors
              3.7.1. The engines shall meet the respective emission limits for each pollutant, as given in paragraph 5.3. of this Regulation, after application of the deterioration factors to the test result as measured