Document ID: chunk:federal_register_of_legislation:F2023C00229:reg:110:p7
Version: federal_register_of_legislation:F2023C00229
Segment Type: reg
Provision Reference: reg 110 (pt 7/59)
Character Range: 621263–623980

points with flow values equally spaced between the lowest qmdw value used during the test and the value of qmdew used during the test. The dilution tunnel may be bypassed.

                  (b) A calibrated mass flow device shall be connected in series to the flowmeter for qmdew and the accuracy shall be checked for the value used for the test. Then the calibrated mass flow device shall be connected in series to the flow meter for qmdw, and the accuracy shall be checked for at least 5 settings corresponding to dilution ratio between 3 and 50, relative to qmdew used during the test.

                  (c) The transfer tube TT shall be disconnected from the exhaust, and a calibrated flow measuring device with a suitable range to measure qmp shall be connected to the transfer tube. Then qmdew shall be set to the value used during the test, and qmdw shall be sequentially set to at least 5 values corresponding to dilution ratios q between 3 and 50. Alternatively, a special calibration flow path, may be provided, in which the tunnel is bypassed, but the total and dilution air flow through the corresponding meters as in the actual test.

                  (d) A tracer gas, shall be fed into the exhaust transfer tube TT. This tracer gas may be a component of the exhaust gas, like CO2 or NOx. After dilution in the tunnel the tracer gas component shall be measured. This shall be carried out for 5 dilu- tion ratios between 3 and 50. The accuracy of the sample flow shall be determined from the dilution ration rd:

                -          The accuracies of the gas analysers shall be taken into account to guarantee the accuracy of qmp.
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        3.2.2. Carbon flow check

                -          A carbon flow check using actual exhaust is recommended for detecting measurement and control problems and verifying the proper operation of the partial flow system. The carbon flow check should be run at least each time a new engine is installed, or something significant is changed in the test cell configuration.

                -          The engine shall be operated at peak torque load and speed or any other steady state mode that produces 5 % or more of CO2. The partial flow sampling system shall be operated with a dilution factor of about 15 to 1.

                -          If a carbon flow check is conducted, the procedure given in Appendix 6 to this Annex shall be applied. The carbon flow rates shall be calculated according to sections 2.1 to 2.3 of Appendix 6 to this Annex. All carbon flow rates should agree to within 6 % of each other.

        3.2.3. Pre-test check

                -          A pre-test check shall be performed within 2 hours before the test