Document ID: chunk:federal_register_of_legislation:F2023L00129:reg:20:p28
Version: federal_register_of_legislation:F2023L00129
Segment Type: reg
Provision Reference: reg 20 (pt 28/29)
Character Range: 295218–298010

the raw exhaust gas, and the particulates are determined using a partial flow dilution system;
(b) The gaseous components and the particulates are determined using a full flow dilution system (CVS system).
 Any combination of the two principles (e.g. raw gaseous measurement and full flow particulate measurement) is permitted.
7.2. Test cycles
7.2.1. Transient test cycle WHTC
 The transient test cycle WHTC is listed in Appendix 1 as a second-by-second sequence of normalized speed and torque values. In order to perform the test on an engine test cell, the normalized values shall be converted to the actual values for the individual engine under test based on the engine-mapping curve. The conversion is referred to as denormalization, and the test cycle so developed as the reference cycle of the engine to be tested. With those references speed and torque values, the cycle shall be run on the test cell, and the actual speed, torque and power values shall be recorded. In order to validate the test run, a regression analysis between reference and actual speed, torque and power values shall be conducted upon completion of the test.
 For calculation of the brake specific emissions, the actual cycle work shall be calculated by integrating actual engine power over the cycle. For cycle validation, the actual cycle work shall be within prescribed limits of the reference cycle work.
 For the gaseous pollutants, continuous sampling (raw or dilute exhaust gas) or batch sampling (dilute exhaust gas) may be used. The particulate sample shall be diluted with a conditioned diluent (such as ambient air), and collected on a single suitable filter. The WHTC is shown schematically in Figure 3.

           Figure 3
           WHTC test cycle
7.2.2. Ramped steady state test cycle WHSC
 The ramped steady state test cycle WHSC consists of a number of normalized speed and load modes which shall be converted to the reference values for the individual engine under test based on the engine-mapping curve. The engine shall be operated for the prescribed time in each mode, whereby engine speed and load shall be changed linearly within 20  1 seconds. In order to validate the test run, a regression analysis between reference and actual speed, torque and power values shall be conducted upon completion of the test.
 The concentration of each gaseous pollutant, exhaust flow and power output shall be determined over the test cycle. The gaseous pollutants may be recorded continuously or sampled into a sampling bag. The particulate sample shall be diluted with a conditioned diluent (such as ambient air). One sample over the complete test procedure shall be taken, and collected on a single suitable filter.
 For calculation of the brake specific emissions, the actual cycle work shall be