Division 4 Determination of PNF1

is the particle number emission, particles per kilometre;

is the volume of the diluted exhaust gas in litres per test (after primary dilution only in the case of double dilution) and corrected to standard conditions (273,15 K (0 °C) and 101,325 kPa);

is a calibration factor to correct the PNC measurements to the level of the reference instrument where this is not applied internally within the PNC. Where the calibration factor is applied internally within the PNC, the calibration factor shall be 1;

is the corrected particle number concentration from the diluted exhaust gas expressed as the arithmetic average number of particles per cubic centimetre from the emissions test including the full duration of the drive cycle. If the volumetric mean concentration results $\bar{C}$ from the PNC are not measured at standard conditions (273,15 K (0 °C) and 101,325 kPa), the concentrations shall be corrected to those conditions $\overline{C_s}$;

is either the dilution air or the dilution tunnel background particle number concentration, as permitted by the approval authority, in particles per cubic centimetre, corrected for coincidence and to standard conditions (273,15 K (0 °C) and 101,325 kPa);

is the mean particle concentration reduction factor of the VPR at the dilution setting used for the test;

is the mean particle concentration reduction factor of the VPR at the dilution setting used for the background measurement;

is the distance driven corresponding to the applicable test cycle, km.

shall be calculated using the following equation:

$\bar{C}=\frac{{\sum }_n^{i=1}{C}_i}{n}$

where:

is a discrete measurement of particle number concentration in the diluted gas exhaust from the PNC; particles per cm³ and corrected for coincidence;

is the total number of discrete particle number concentration measurements made during the applicable test cycle and shall be calculated using the following equation:

n = t × f

where:

is the time duration of the applicable test cycle, s;

is the data logging frequency of the particle counter, Hz.