Document ID: chunk:federal_register_of_legislation:F2023C00229:reg:5:p17
Version: federal_register_of_legislation:F2023C00229
Segment Type: reg
Provision Reference: reg 5 (pt 17/36)
Character Range: 466915–469862

response of the measuring system whereby the change of the measured component is at least 60 % FS and takes place in less than 0,1 second. The system response time (t90) consists of the delay time to the system and of the rise time of the system (see also ISO 16183);

         "rise time" means the time between the 10 % and 90 % response of the final reading (t90 – t10). This is the instrument response after the component to be measured has reached the instrument. For the rise time, the sampling probe is defined as the reference point;

         "self adaptability" means any engine device allowing the air/fuel ratio to be kept constant;

         "smoke" means particles suspended in the exhaust stream of a diesel engine which absorb, reflect, or refract light;

         "test cycle" means a sequence of test points each with a defined speed and torque to be followed by the engine under steady state (ESC test) or transient operating conditions (ETC, ELR test);

         "torque limiter" means a device that temporarily limits the maximum torque of the engine;

         "transformation time" means the time between the change of the component to be measured at the sampling probe and a system response of 50 % of the final reading (t50). The transformation time is used for the signal alignment of different measurement instruments;

         "useful life" means, for vehicles and engines that are type-approved to either row B1, row B2 or row C of the table given in section 6.2.1 of this Annex, the relevant period of distance and/or time that is defined in Article 3 (durability of emission control systems) of this Direc- tive over which compliance with the relevant gaseous, particulate and smoke emission limits has to be assured as part of the type-approval;

         "Wobbe Index (lower Wl; or upper Wu)" means the ratio of the corresponding calorific value of a gas per unit volume and the square root of its relative density under the same reference conditions:

         "λ-shift factor (Sλ)" means an expression that describes the required flexibility of the engine management system regarding a change of the excess-air ratio λ if the engine is fuelled with a gas composition different from pure methane (see Annex VII for the calculation of Sλ).
        2.2.         Symbols, abbreviations and international standards

        2.2.1.    Symbols for test parameters

Symbol  Unit        Term
Ap      m2          Cross sectional area of the isokinetic sampling probe
Ae      m2          Cross sectional area of the exhaust pipe
c       ppm/vol. %  Concentration
Cd      —           Discharge coefficient of SSV-CVS
C1      —           Carbon 1 equivalent hydrocarbon
d       m           Diameter
D0      m3/s        Intercept of PDP calibration function
D       —           Dilution factor
D       —           Bessel function constant
E       —           Bessel function constant
EE      —           Ethane efficiency
EM