Document ID: chunk:federal_register_of_legislation:F2023C00229:reg:4:p23
Version: federal_register_of_legislation:F2023C00229
Segment Type: reg
Provision Reference: reg 4 (pt 23/42)
Character Range: 64997–68571

damage or failure, or is used to facilitate engine starting. An auxiliary control device may also be   a strategy or measure that has been satisfactorily demonstrated not to be a defeat device;

2.31.                          'irrational emission control strategy' means any strategy or measure that, when the vehicle is operated under normal conditions of use, reduces the effectiveness of the emission control system to a level below that expected on the applicable emission test procedures.

2.32.                          Symbols and abbreviations

2.32.1.                      Symbols for test parameters

  Symbol    Unit                     Term
AP         m2           Cross sectional area of the isokinetic sampling probe
AT         m2           Cross sectional area of the exhaust pipe
CEE        —            Ethane efficiency
CEM        —            Methane efficiency
C1         —            Carbon 1 equivalent hydrocarbon
conc       ppm/vol. %   Subscript denoting concentration
D0         m3/s         Intercept of PDP calibration function
DF         —            Dilution factor
D          —            Bessel function constant
E          —            Bessel function constant
EZ         g/kWh        Interpolated NOx emission of the control point
fa         —            Laboratory atmospheric factor
fc         s-1          Bessel filter cut-off frequency
FFH        —            Fuel specific factor for the calculation of wet concentration for dry concentration
FS         —            Stoichiometric factor
GAIRW      kg/h         Intake air mass flow rate on wet basis
GAIRD      kg/h         Intake air mass flow rate on dry basis
GDILW      kg/h         Dilution air mass flow rate on wet basis
GEDFW      kg/h         Equivalent diluted exhaust gas mass flow rate on wet basis
GEXHW      kg/h         Exhaust gas mass flow rate on wet basis
GFUEL      kg/h         Fuel mass flow rate
GTOTW      kg/h         Diluted exhaust gas mass flow rate on wet basis
H          MJ/m3        Calorific value
HREF       g/kg         Reference value of absolute humidity (10,71g/kg)
Ha         g/kg         Absolute humidity of the intake air
Hd         g/kg         Absolute humidity of the dilution air
HTCRAT     mol/mol      Hydrogen-to-Carbon ratio
i          —            Subscript denoting an individual mode
K          —            Bessel constant
k          m-1          Light absorption coefficient
KH,D       —            Humidity correction factor for NOx for diesel engines
KH,G       —            Humidity correction factor for NOx for gas engines
KV                      CFV calibration function
KW,a       —            Dry to wet correction factor for the intake air
KW,d       —            Dry to wet correction factor for the dilution air
KW,e       —            Dry to wet correction factor for the diluted exhaust gas
KW,r       —            Dry to wet correction factor for the raw exhaust gas
L          %            Percent torque related to the maximum torque for the test engine
La         m            Effective optical path length
m                       Slope of PDP calibration function
mass       g/h or g     Subscript denoting emissions mass flow (rate)
MDIL       kg           Mass of the dilution air sample passed through the particulate sampling filters
Md         mg           Particulate sample mass of the dilution air collected
Mf         mg           Particulate sample mass collected
Mf,p       mg           Particulate sample mass collected on primary filter
Mf,b       mg           Particulate sample mass collected