# 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 2.1.6.2: Tracer measurement method

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

This involves measurement of the concentration of a tracer gas in the exhaust gas. The instantaneous exhaust gas flow q mew,i [kg/s] shall be calculated by means of equation (7-16):
q m ew, i = q V t × ρ e 10 − 6 × c mix, i − c b
(7-16)
where:
qV t tracer gas flow rate [m3/s]
c mix, i instantaneous concentration of the tracer gas after mixing [ppm]
ρ e density of the raw exhaust gas [kg/m3]
c b background concentration of the tracer gas in the intake air [ppm]
The background concentration of the tracer gas c b may be determined by averaging the background concentration measured immediately before the test run and after the test run. When the background concentration is less than 1 % of the concentration of the tracer gas after mixing c mix, i at maximum exhaust gas flow, the background concentration may be neglected.

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Source: https://www.legislation.gov.uk/eur/2017/654/annex/VII/division/2/division/2.1/division/2.1.6/division/2.1.6.2 (the official version)
Page: https://openlegislation.uk/eu-regulation-2017-654/annex-VII/division-2/division-2.1/division-2.1.6/division-2.1.6.2
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.