Document ID: chunk:federal_register_of_legislation:F2011C00805:reg:20:p16
Version: federal_register_of_legislation:F2011C00805
Segment Type: reg
Provision Reference: reg 20 (pt 16/23)
Character Range: 187452–190472

: flow through tunnel;

                   M : particulate mass (g/km);

                   Mlimit  : limit mass of particulates (limit mass in force, g/km);

                   m : mass of particulates collected by filters (g);

                   d : distance corresponding to the operating cycle (km).

           The particulates sample rate (Vep/Vmix) shall be adjusted so that for M = Mlimit,  1  m  5 mg (when 47 mm diameter filters are used).

           The filter surface shall consist of a material that is hydrophobic and inert towards the components of the exhaust gas (fluorocarbon coated glass fibre filters or equivalent).

           4.3.1.2.   Accuracy

           The analysers shall have a measuring range compatible with the accuracy required to measure the concentrations of the exhaust gas sample pollutants.

           Measurement error shall not exceed  2 per cent (intrinsic error of analyser) disregarding the true value for the calibration gases.

           For concentrations of less than 100 ppm the measurement error shall not exceed  2 ppm.

           The ambient air sample shall be measured on the same analyser with an appropriate range.

           The microgram balance used to determine the weight of all filters shall have accuracy of 5 μg (standard deviation) and readability of 1 μg.

           4.3.1.3.  Ice-trap

           No gas drying device shall be used before the analysers unless shown to have no effect on the pollutant content of the gas stream.
           4.3.2.  Particular requirements for compression-ignition engines

           A heated sample line for a continuous HC-analysis with the flame ionisation detector (HFID), including recorder (R) shall be used. The average concentration of the measured hydrocarbons shall be determined by integration. Throughout the test, the temperature of the heated sample line shall be controlled at 463 K (190 C)  10 K. The heated sampling line shall be fitted with a heated filter (FH) 99 per cent efficient with particles  0.3 μm, to extract any solid particles from the continuous flow of gas required for analysis.

           The sampling system response time (from the probe to the analyser inlet) shall be no more than four seconds.

           The HFID shall be used with a constant flow (heat exchanger) system to ensure a representative sample, unless compensation for varying CFV or CFO flow is made.

           The particulate sampling unit shall consist of a dilution tunnel, a sampling probe, a filter unit, a partial-flow pump, and flow rate regulators and measuring units. The particulate-sampling part flow is drawn through two series-mounted filters. The sampling probe for the test gas flow for particulates shall be so arranged within the dilution tract that a representative sample gas flow can be taken from the homogeneous air/exhaust mixture and an air/exhaust gas mixture temperature of 325 K (52 C) is not exceeded immediately before the particulate filter. The temperature of the gas