Document ID: chunk:federal_register_of_legislation:F2024L00447:reg:0:p28
Version: federal_register_of_legislation:F2024L00447
Segment Type: reg
Provision Reference: reg 0 (pt 28/57)
Character Range: 169131–171962

°C and 101.3 kPa. Compliance may be demonstrated by measuring the temperature at the outlet of a thermal sample dryer or by measuring the humidity at a point just upstream of the CLD. The humidity of the CLD exhaust might also be measured as long as the only flow into the CLD is the flow from the sample dryer.

              (f) Sample dryer NO2 penetration

                  Liquid water remaining in an improperly designed sample dryer can remove NO2 from the sample. If a sample dryer is used in combination with a NDUV analyser without an NO2/NO converter upstream, water could therefore remove NO2 from the sample prior to the NOX measurement. The sample dryer shall allow for measuring at least 95 per cent of the NO2 contained in a gas that is saturated with water vapour and consists of the maximum NO2 concentration expected to occur during emission testing.

              4.4. Response time check of the analytical system

              For the response time check, the settings of the analytical system shall be exactly the same as during the emissions test (i.e. pressure, flow rates, filter settings in the analysers and all other parameters influencing the response time). The response time shall be determined with gas switching directly at the inlet of the sample probe. The gas switching shall be done in less than 0.1 second. The gases used for the test shall cause a concentration change of at least 60 per cent full scale of the analyser.

              The concentration trace of each single gas component shall be recorded.

              For time alignment of the analyser and exhaust flow signals, the transformation time is defined as the time from the change (t0) until the response is 50 per cent of the final reading (t50).

              The system response time shall be ≤ 12 s with a rise time of ≤ 3 seconds for all components and all ranges used. When using a NMC for the measurement of NMHC, the system response time may exceed 12 seconds.

              5. Gases

              5.1. Calibration and span gases for RDE tests

              5.1.1. General

              The shelf life of calibration and span gases shall be respected. Pure as well as mixed calibration and span gases shall fulfil the specifications of Annex B5 of UN Regulation No. 154 on WLTP.

              5.1.2. NO2 calibration gas

              In addition, NO2 calibration gas is permissible. The concentration of the NO2 calibration gas shall be within two per cent of the declared concentration value. The amount of NO contained in the NO2 calibration gas shall not exceed 5 per cent of the NO2 content.

              5.1.3. Multicomponent mixtures

              Only multicomponent mixtures which fulfil the requirements of paragraph 5.1.1. shall be used. These mixtures may contain two or more of the components.