# Commission Delegated Regulation (EU) 2017/654 of 19 December 2016 supplementing Regulation (EU) 2016/1628 of the European Parliament and of the Council with regard to technical and general requirements relating to emission limits and type-approval for internal combustion engines for non-road mobile machinery, Division 3.9.1: Reference meter conversions

Extent: E+W+S+N.I.

The calibration equations in this section use molar flow rate, ṅ ref , as a reference quantity. If the adopted reference meter outputs a flow rate in a different quantity, such as standard volume rate, V̇ stdref actual volume rate, V̇ actdref, or mass rate, ṁ ref, the reference meter output shall be converted to a molar flow rate by means of equations (7-136), (7-137) and (7-138), noting that while values for volume rate, mass rate, pressure, temperature, and molar mass may change during an emission test, they should be kept as constant as practical for each individual set point during a flow meter calibration:
ṅ ref = V stdref × p std T std × R = V actref × p act T act × R = ṁ ref M mix
(7-136)
where:
ṅ ref reference molar flow rate [mol/s]
V̇ stdref reference volume flow rate, corrected to a standard pressure and a standard temperature [m3/s]
V̇ actref reference volume flow rate, at the actual pressure and temperature [m3/s]
ṁ ref reference mass flow [g/s]
p std standard pressure [Pa]
p act actual pressure of the gas [Pa]
T std standard temperature [K]
T act actual temperature of the gas [K]
R molar gas constant [J/(mol · K)]
M mix molar mass of the gas [g/mol]

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Source: https://www.legislation.gov.uk/eur/2017/654/annex/VII/division/3/division/3.9/division/3.9.1 (the official version)
Page: https://openlegislation.uk/eu-regulation-2017-654/annex-VII/division-3/division-3.9/division-3.9.1
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.