Division 2.1.6.2 Tracer measurement method

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):

where:

q_{V 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.