Document ID: chunk:federal_register_of_legislation:F2023C00229:reg:10:p7
Version: federal_register_of_legislation:F2023C00229
Segment Type: reg
Provision Reference: reg 10 (pt 7/30)
Character Range: 539497–542470

sealed filter holder until needed for testing. The filter shall be used within eight hours of its removal from the weighing chamber. The tare weight shall be recorded.'

       (ii)     Section 2.7.4. is replaced by the following: '2.7.4. Particulate Sampling
              One filter shall be used for the complete test procedure. The modal weighting factors specified in the test cycle procedure shall be taken into account by taking a sample proportional to the exhaust mass flow during each individual mode of the cycle. This can be achieved by adjusting sample flow rate, sampling time, and/or dilution ratio, accordingly, so that the criterion for the effective weighting factors in section 5.6 is met.

              The sampling time per mode must be at least 4 seconds per 0,01 weighting factor. Sampling must be conducted as late as possible within each mode. Particulate sampling shall be completed no earlier than 5 seconds before the end of each mode.'

       (iii)   The following new section 4 is inserted:

       '4.  CALCULATION OF THE EXHAUST GAS FLOW

        4.1.  Determination of Raw Exhaust Gas Mass Flow

              For calculation of the emissions in the raw exhaust, it is necessary to know the exhaust gas flow. The exhaust gas mass flow rate shall be determined in accordance with section 4.1.1 or 4.1.2. The accuracy of exhaust flow determination shall be ± 2,5 % of read- ing or ± 1,5 % of the engine's maximum value whichever is the greater. Equivalent methods (e.g. those described in section 4.2 of Appendix 2 to this Annex) may be used.

        4.1.1. Direct measurement method

             Direct measurement of the exhaust flow may be done by systems such as:

                -          pressure differential devices, like flow nozzle,

                -          ultrasonic flowmeter,

                -          vortex flowmeter.

              Precautions shall be taken to avoid measurement errors which will impact emission value errors. Such precautions include the care- ful installation of the device in the engine exhaust system according to the instrument manufacturers' recommendations and to good engineering practice. Especially, engine performance and emissions shall not be affected by the installation of the device.

        4.1.2. Air and fuel measurement method

              This involves measurement of the air flow and the fuel flow. Air flowmeters and fuel flowmeters shall be used that meet the total accuracy requirement of section 4.1. The calculation of the exhaust gas flow is as follows:

        4.2.  Determination of Diluted Exhaust Gas Mass Flow

              For calculation of the emissions in the diluted exhaust using a full flow dilution system it is necessary to know the diluted exhaust gas flow. The flow rate of the diluted exhaust (qmdew) shall be measured over each mode with a PDP-CVS, CFV-CVS or SSV-CVS in line with the general formulae given in section 4.1 of Appendix 2 to this