Document ID: chunk:federal_register_of_legislation:F2024L00447:reg:0:p31
Version: federal_register_of_legislation:F2024L00447
Segment Type: reg
Provision Reference: reg 0 (pt 31/57)
Character Range: 177056–180058

UN Regulation No. 154 on WLTP automatically comply with the calibration requirements of this annex.

              6.2. Efficiency requirements

              The complete PN analyser system including the sampling line shall fulfil the efficiency requirements of Table A5/3a.

    Table A5/3a
    PN analyser (including the sampling line) system efficiency requirements

dp [nm]            Sub-23            23         30         50         70         100        200

E(dp) PN analyser  To be determined  0.2 – 0.6  0.3 – 1.2  0.6 – 1.3  0.7 – 1.3  0.7 – 1.3  0.5 – 2.0

Efficiency E(dp) is defined as the ratio in the readings of the PN analyser system to a reference Condensation Particle Counter (CPC)'s (d50 % = 10 nm or lower, checked for linearity and calibrated with an electrometer) or an Electrometer's number concentration measuring in parallel monodisperse aerosol of mobility diameter dp and normalized at the same temperature and pressure conditions.
              The material should be thermally stable soot-like (e.g. spark discharged graphite or diffusion flame soot with thermal pre-treatment). If the efficiency curve is measured with a different aerosol (e.g. NaCl), the correlation to the soot-like curve must be provided as a chart which compares the efficiencies obtained using both test aerosols. The differences in the counting efficiencies shall be taken into account by adjusting the measured efficiencies based on the provided chart to give soot-like aerosol efficiencies. The correction for multiply charged particles shall be applied and documented but shall not exceed 10 per cent. These efficiencies refer to the PN analysers with the sampling line. The PN analyser can also be calibrated in parts (i.e. the pre-conditioning unit separately from the particle detector) as long as it is proven that the PN analyser and the sampling line together fulfil the requirements of Table A5/3a. The measured signal from the detector shall be > 2 times the limit of detection (here defined as the zero level plus 3 standard deviations).

              6.3. Linearity requirements

              The PN analyser including the sampling line shall fulfil the linearity requirements of paragraph 3.2. of Annex 5 using monodisperse or polydisperse soot-like particles. The particle size (mobility diameter or count median diameter) shall be larger than 45 nm. The reference instrument shall be an Electrometer or a Condensation Particle Counter (CPC) with d50 = 10 nm or lower, verified for linearity. Alternatively, a particle number system compliant with UN Regulation No. 154 on WLTP.

              In addition, the differences of the PN analyser from the reference instrument at all points checked (except the zero point) shall be within 15 per cent of their mean value. At least 5 points equally distributed (plus the zero) shall be checked. The maximum checked concentration shall be > 90 per cent of the PN analyser nominal measurement range.

              If the PN analyser