Document ID: chunk:federal_register_of_legislation:F2023L00129:reg:13:p42
Version: federal_register_of_legislation:F2023L00129
Segment Type: reg
Provision Reference: reg 13 (pt 42/56)
Character Range: 410640–413649

(d)           The minimum dilution ratio shall be within the range of 5:1 to 7:1 and at least 2:1 for the primary dilution stage based on the maximum engine exhaust flow rate;

                  (e)            For a partial flow dilution system, the residence time in the system from the point of diluent introduction to the filter holder(s) shall be between 0.5 and 5 seconds;

                  (f)             For a full flow dilution system, the overall residence time in the system from the point of diluent introduction to the filter holder(s) shall be between 1 and 5 seconds, and the residence time in the secondary dilution system, if used, from the point of secondary diluent introduction to the filter holder(s) shall be at least 0.5 seconds.

Dehumidifying the diluent before entering the dilution system is permitted, and especially useful if diluent humidity is high.
9.4.3. Particulate sampling
9.4.3.1. Partial flow dilution system
 The particulate sampling probe shall be installed in close proximity to the gaseous emissions sampling probe, but sufficiently distant as to not cause interference. Therefore, the installation provisions of paragraph 9.3.10. also apply to particulate sampling. The sampling line shall conform to the requirements laid down in Appendix 2 to this annex.
 In the case of a multi-cylinder engine with a branched exhaust manifold, the inlet of the probe shall be located sufficiently far downstream so as to ensure that the sample is representative of the average exhaust emissions from all cylinders. In multi-cylinder engines having distinct groups of manifolds, such as in a "Vee" engine configuration, it is recommended to combine the manifolds upstream of the sampling probe. If this is not practical, it is permissible to acquire a sample from the group with the highest particulate emission. For exhaust emission calculation the total exhaust mass flow of the manifold shall be used.
9.4.3.2. Full flow dilution system
 The particulate sampling probe shall be installed in close proximity to the gaseous emissions sampling probe, but sufficiently distant as to not cause interference, in the dilution tunnel. Therefore, the installation provisions of paragraph 9.3.11. also apply to particulate sampling. The sampling line shall conform to the requirements laid down in Appendix 2 to this annex.
9.4.4. Particulate sampling filters
 The diluted exhaust shall be sampled by a filter that meets the requirements of paragraphs 9.4.4.1. to 9.4.4.3. during the test sequence.
        9.4.4.1. Filter specification

              All filter types shall have a 0.3 μm DOP (di-octylphthalate) or PAO (poly-alpha-olefin) collection efficiency of at least 99 per cent. The sample filter manufacturer's measurements reflected in their product ratings may be used to show this requirement. The filter material shall be either:

              (a) Fluorocarbon (PTFE) coated glass fibre, or

              (b) Fluorocarbon (PTFE) membrane.
9.4.4.2. Filter size
 The filter