Document ID: chunk:federal_register_of_legislation:F2023L00129:reg:13:p14
Version: federal_register_of_legislation:F2023L00129
Segment Type: reg
Provision Reference: reg 13 (pt 14/56)
Character Range: 333543–336597

from relative humidity measurement, dew point measurement, vapour pressure measurement or dry/wet bulb measurement using generally accepted equations.
       8.2.1. Compression-ignition engines
               (23)
 Where:

 Ha is the intake air humidity, g water per kg dry air
8.2.2. Positive ignition engines
  (24)
 Where:

 Ha is the intake air humidity, g water per kg dry air
8.3. Particulate filter buoyancy correction
 The sampling filter mass shall be corrected for its buoyancy in air. The buoyancy correction depends on sampling filter density, air density and the density of the balance calibration weight, and does not account for the buoyancy of the PM itself. The buoyancy correction shall be applied to both tare filter mass and gross filter mass.
 If the density of the filter material is not known, the following densities shall be used:
(a) Teflon coated glass fiber filter: 2,300 kg/m3;
(b) Teflon membrane filter: 2,144 kg/m3;
(c) Teflon membrane filter with polymethylpentene support ring: 920 kg/m3.
 For stainless steel calibration weights, a density of 8,000 kg/m3 shall be used. If the material of the calibration weight is different, its density shall be known.
 The following equation shall be used:
  (25)
 With
                          (26)
 Where:
                   muncor is the uncorrected particulate filter mass, mg
                   ρa is the density of the air, kg/m3
                   ρw is the density of balance calibration weight, kg/m3
                   ρf is the density of the particulate sampling filter, kg/m3
                   pb is the total atmospheric pressure, kPa
                   Ta is the air temperature in the balance environment, K
                   28.836 is the molar mass of the air at reference humidity (282.5 K), g/mol
                   8.3144 is the molar gas constant
 The particulate sample mass mp used in paragraphs 8.4.3. and 8.5.3. shall be calculated as follows:
  (27)
 Where:
mf,G is the buoyancy corrected gross particulate filter mass, mg
mf,T is the buoyancy corrected tare particulate filter mass, mg
8.4. Partial flow dilution (PFS) and raw gaseous measurement
 The instantaneous concentration signals of the gaseous components are used for the calculation of the mass emissions by multiplication with the instantaneous exhaust mass flow rate. The exhaust mass flow rate may be measured directly, or calculated using the methods of intake air and fuel flow measurement, tracer method or intake air and air/fuel ratio measurement. Special attention shall be paid to the response times of the different instruments. These differences shall be accounted for by time aligning the signals. For particulates, the exhaust mass flow rate signals are used for controlling the partial flow dilution system to take a sample proportional to the exhaust mass flow rate. The quality of proportionality shall be checked by applying a regression analysis between sample and exhaust flow in accordance with paragraph 9.4.6.1. The complete test set up is schematically shown in Figure