Document ID: chunk:federal_register_of_legislation:F2024L00447:reg:0:p13
Version: federal_register_of_legislation:F2024L00447
Segment Type: reg
Provision Reference: reg 0 (pt 13/57)
Character Range: 127484–130602

an initial stabilization period the pressure increase Δp (kPa/min) in the system shall not exceed:

              where:

              pe is the evacuated pressure [Pa],

              Vs is the system volume [l],

              qvs is the volume flow rate of the system [l/min].

              Alternatively, a concentration step change at the beginning of the sampling line shall be introduced by switching from zero to span gas while maintaining the same pressure conditions as under normal system operation. If for a correctly calibrated analyser after an adequate period of time the reading is ≤ 99 per cent compared to the introduced concentration, the leakage problem shall be corrected.

              4.2. Starting and stabilizing the PEMS

              The PEMS shall be switched on, warmed up and stabilized in accordance with the specifications of the PEMS manufacturer until key functional parameters (e.g., pressures, temperatures and flows) have reached their operating set points before test start. To ensure correct functioning, the PEMS may be kept switched on or can be warmed up and stabilized during vehicle conditioning. The system shall be free of errors and critical warnings.

              4.3. Preparing the sampling system

              The sampling system, consisting of the sampling probe and sampling lines shall be prepared for testing by following the instruction of the PEMS manufacturer. It shall be ensured that the sampling system is clean and free of moisture condensation.

              4.4. Preparing the Exhaust mass Flow Meter (EFM)

              If used for measuring the exhaust mass flow, the EFM shall be purged and prepared for operation in accordance with the specifications of the EFM manufacturer. This procedure shall, if applicable, remove condensation and deposits from the lines and the associated measurement ports.

              4.5. Checking and calibrating the analysers for measuring gaseous emissions

              Zero and span calibration adjustments of the analysers shall be performed using calibration gases that meet the requirements of paragraph 5. of Annex 5. The calibration gases shall be chosen to match the range of pollutant concentrations expected during the RDE test. To minimise analyser drift, it is recommended to conduct the zero and span calibration of analysers at an ambient temperature that resembles, as closely as possible, the temperature experienced by the test equipment during the trip.

              4.6. Checking the analyser for measuring particle emissions

              The zero level of the analyser shall be recorded by sampling HEPA filtered ambient air at an appropriate sampling point, ideally at the inlet of the sampling line. The signal shall be recorded at a constant frequency which is a multiple of 1.0 Hz averaged over a period of 2 minutes. The final concentration shall be within the manufacturer's specifications, but shall not exceed 5,000 particles per cubic-centimetre.

              4.7. Determining vehicle speed

              Vehicle speed shall be determined by at least one of the following