Document ID: chunk:federal_register_of_legislation:F2023L00129:reg:13:p53
Version: federal_register_of_legislation:F2023L00129
Segment Type: reg
Provision Reference: reg 13 (pt 53/56)
Character Range: 438780–442014

sample mass flow rate, kg/s.
                    The qex signal sent to the partial flow system controller shall be accurate to within 0.1 per cent of qmdew at all times and should be sent with frequency of at least 1 Hz.
                   (b) In the case where the extracted particle number sample flow is fully or partially discarded, but an equivalent flow is fed back to the dilution system upstream of the flow measurement device, equation 83 in paragraph 9.4.6.2. shall be replaced by the following:
                     (93)
                 Where:
                          qmp = sample flow of exhaust gas into partial flow dilution system, kg/s,
                      qmdew = diluted exhaust mass flow rate, kg/s,
                      qmdw = dilution air mass flow rate, kg/s,
                      qex = particle number sample mass flow rate, kg/s,
                          qsw = mass flow rate fed back into dilution tunnel to compensate for particle number sample extraction, kg/s.
               The difference between qex and qsw sent to the partial flow system controller shall be accurate to within 0.1 per cent of qmdew at all times. The signal (or signals) should be sent with frequency of at least 1 Hz.
              10.3.3. Correction of PM measurement
               When a particle number sample flow is extracted from a total sampling partial flow dilution system, the mass of particulates (mPM) calculated in paragraph 8.4.3.2.1. or 8.4.3.2.2. shall be corrected as follows to account for the flow extracted. This correction is required even where filtered extracted flow is fed back into the partial flow dilution systems.
                (94)
               Where:
                      mPM,corr = mass of particulates corrected for extraction of particle number sample flow, g/test,
                      mPM = mass of particulates determined according to paragraph 8.4.3.2.1. or 8.4.3.2.2., g/test,
                      msed = total mass of diluted exhaust gas passing through the dilution tunnel, kg,
                      mex = total mass of diluted exhaust gas extracted from the dilution tunnel for particle number sampling, kg.
              10.3.4. Proportionality of partial flow dilution sampling
               For particle number measurement, exhaust mass flow rate, determined according to any of the methods described in paragraphs 8.4.1.3. to 8.4.1.7., is used for controlling the partial flow dilution system to take a sample proportional to the exhaust mass flow rate. The quality of proportionality shall be checked by applying a regression analysis between sample and exhaust flow in accordance with paragraph 9.4.6.1.
              10.4. Determination of particle numbers
              10.4.1. Time alignment
               For partial flow dilution systems residence time in the particle number sampling and measurement system shall be accounted for by time aligning the particle number signal with the test cycle and the exhaust gas mass flow rate according to the procedure in paragraph 8.4.2.2. The transformation time of the particle number sampling and measurement system shall be determined according to paragraph A.8.1.3.7. of Appendix 8 to this annex.
              10.4.2.