Document ID: chunk:federal_register_of_legislation:F2023C00229:reg:10:p29
Version: federal_register_of_legislation:F2023C00229
Segment Type: reg
Provision Reference: reg 10 (pt 29/30)
Character Range: 600472–603359

section 2.3.1 of Annex V (EP).

              The gaseous emissions sample probe(s) shall be installed in the dilution tunnel at a point where the dilution air and exhaust gas are well mixed, and in close proximity to the particulates sampling probe.

             Sampling can generally be done in two ways:

                -          the pollutants are sampled into a sampling bag over the cycle and measured after completion of the test,
                -          the pollutants are sampled continuously and integrated over the cycle; this method is mandatory for HC and NOx.

        4.   DETERMINATION OF THE PARTICULATES

              The determination of the particulates requires a dilution system. Dilution may be accomplished by a partial flow dilution system or a full flow double dilution system. The flow capacity of the dilution system shall be large enough to completely eliminate water condensation in the dilution and sampling systems. The temperature of the diluted exhaust gas shall be below 325 K (52 °C) (*) immediately upstream of the filter holders. Humidity control of the dilution air before entering the dilution system is permitted, and especially dehumidifying is useful if dilution air humidity is high. The temperature of the dilution air shall be higher than 288 K (15 °C) in close proximity to the entrance into the dilution tunnel.

              The partial flow dilution system has to be designed to extract a proportional raw exhaust sample from the engine exhaust stream, thus responding to excursions in the exhaust stream flow rate, and introduce dilution air to this sample to achieve a temperature below 325 K (52 °C) at the test filter. For this it is essential that the dilution ratio or the sampling ratio rdil or rs be determined such that the accuracy limits of section 3.2.1 of Appendix 5 to this Annex are fulfilled. Different extraction methods can be applied, whereby the type of extraction used dictates to a significant degree the sampling hardware and procedures to be used (section 2.2 of Annex V).

              In general, the particulate sampling probe shall be installed in close proximity to the gaseous emissions sampling probe, but suf- ficiently distant as to not cause interference. Therefore, the installation provisions of section 3.4.1 also apply to particulate sam- pling. The sampling line shall conform to the requirements of section 2 of Annex V.

              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