Document ID: chunk:federal_register_of_legislation:F2023L00129:reg:10:p14
Version: federal_register_of_legislation:F2023L00129
Segment Type: reg
Provision Reference: reg 10 (pt 14/150)
Character Range: 753255–756331

contamination of the sampling system by condensed hydrocarbons.
              The sample probe shall be installed in the exhaust pipe in accordance with the requirements of paragraph 9.3.10. of Annex 4.
              If the length of the sample line is changed, the system transport times shall be verified and if necessary corrected.
              A.1.2.4.6. Installation of PM number analyser

              The installation and operation of the PEMS shall be leak-tight and minimise heat loss. To avoid the generation of particles, connectors shall be thermally stable at the exhaust gas temperatures expected during the test. Where elastomer connectors are used to connect the vehicle exhaust outlet and the connecting tube, those connectors shall have no contact with the exhaust gas to avoid artefacts at high engine load.

              A.1.2.4.7. Sampling of PM number emissions

              Emissions sampling shall be representative and conducted at locations of well-mixed exhaust gas where the influence of ambient air downstream of the sampling point is minimal. Where applicable, emissions shall be sampled downstream of the exhaust mass flow meter, respecting a distance of at least 150 mm to the flow sensing element. The sampling probe shall be fitted at least 3 times the inner diameter of the exhaust pipe upstream of the point at which the exhaust exits into the environment. The exhaust shall be sampled from the centre of the exhaust stream. Where several probes are used for emissions sampling, the particle sampling probe shall be placed upstream of the other sampling probes. The particle sampling probe shall not interfere with the sampling of gaseous pollutants. The type and specifications of the probe and its mounting shall be documented in detail, either in the test report of the Technical Service (in the case of testing at type approval) or in the vehicle manufacturer's own documentation (in case of in-service conformity testing).

              Where particles are sampled and not diluted at the tailpipe, the sampling line from the raw exhaust sample point to the point of dilution or particle detector shall be heated to a minimum of 373 K (100 °C).

              All parts of the sampling system, from the exhaust pipe to the particle detector, which are in contact with raw or diluted exhaust gas, shall be designed to minimise the deposition of particles. All parts shall be made from anti-static material to prevent electrostatic effects.
              A.1.2.5. Pre-test procedures
              A.1.2.5.1. Starting and stabilizing the PEMS instruments
              The main units shall be warmed up and stabilized, according to the instrument manufacturer specifications, until pressures, temperatures and flows have reached their operating set points.
              A.1.2.5.2. Cleaning the sampling system
              To prevent system contamination, the sampling lines of the PEMS instruments shall be purged until sampling begins, according to the instrument manufacturer specifications.
A.1.2.5.3. Checking and calibrating