Document ID: chunk:federal_register_of_legislation:F2023C00229:reg:9:p23
Version: federal_register_of_legislation:F2023C00229
Segment Type: reg
Provision Reference: reg 9 (pt 23/71)
Character Range: 273510–276540

and the full flow dilution system shall conform to the requirements of Annex V, Section 2.3.1, 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.
              For the ETC, 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 (ESC only) or a full flow dilution system (mandatory for ETC). The flow capacity of the dilution system shall be large enough to completely eliminate water condensation in the dilution and sampling systems, and maintain the temperature of the diluted exhaust gas at or below 325K (52 °C) immediately upstream of the filter holders. Dehumidifying the dilution air before entering the dilution system is permitted, and especially useful if dilution air humidity is high. The temperature of the dilution air shall be 298 K ± 5 K (25 °C ± 5 °C). If the ambient temperature is below 293 K (20 °C), dilution air pre-heating above the upper temperature limit of 303K (30 °C) is recommended. However, the dilution air temperature must not exceed 325 K (52 °C) prior to the introduction of the exhaust in the dilution tunnel.

              The partial flow dilution system has to be designed to split the exhaust stream into two fractions, the smaller one being diluted with air and subsequently used for particulate measurement. For this it is essential that the dilution ratio be determined very accurately. Different splitting methods can be applied, whereby the type of splitting used dictates to a significant degree the sampling hardware and procedures to be used (Annex V, Section 2.2). The particulate sampling probe shall be installed in close proximity to the gaseous emissions sampling probe, and the installation shall comply with the provisions of Section 3.4.1.

              To determine the mass of the particulates, a particulate sampling system, particulate sampling filters, a microgram balance, and a temperature and humidity controlled weighing chamber, are required.

              For particulate sampling, the single filter method shall be applied which uses one pair of filters (see Section 4.1.3) for the whole test cycle. For the ESC, considerable attention must be paid to sampling times and flows during the sampling phase of the test.

4.1.                            Particulate sampling filters

4.1.1.                        Filter specification

              Fluorocarbon coated glass fibre filters or fluorocarbon based membrane filters