Document ID: chunk:federal_register_of_legislation:F2023C00229:reg:9:p22
Version: federal_register_of_legislation:F2023C00229
Segment Type: reg
Provision Reference: reg 9 (pt 22/22)
Character Range: 207287–208452

not filtered, measurements at the beginning and at the end of the cycle, may be done, and the values averaged.

2.5.                            Adjustment of the dilution ratio

              The dilution air shall be set such that  the temperature of  the diluted exhaust gas  measured immediately  prior to the primary filter shall not exceed 325 K (52 °C) at any mode. The dilution ratio (q) shall not be    less than 4.

              For systems that use CO2 or NOx concentration measurement for dilution ratio control, the CO2 or NOx content of the dilution air must be measured at the beginning and at the end of each test. The pre- and post-test background CO2 or NOx concentration  measurements  of  the  dilution  air  must  be  within 100 ppm or 5 ppm of each other, respectively.

2.6.                            Checking the analysers

              The emission analysers shall be set at zero and spanned.

2.7.                            Test cycle

2.7.1.                        The following 13-mode cycle shall be followed in dynamometer operation on the test engine
 Mode number   Engine speed    Percent load   Weighting factor    Mode length