Report - DCE - Nationalt Center for Miljø og Energi

For all vehicle categories/technology levels not represented by measurements,
the emission factors are produced by using reduction factors. The latter
factors are determined by assessing the EU emission limits and the relevant
emission approval test conditions, for each vehicle type and Euro class.
%FUFSJPSBUJPO GBDUPST
For three-way catalyst cars the emissions of NOX, NMVOC and CO gradually
increase due to catalyst wear and are, therefore, modified as a function
of total mileage by the so-called deterioration factors. Even though the emission
curves may be serrated for the individual vehicles, on average, the
emissions from catalyst cars stabilise after a given cut-off mileage is reached
due to OBD (On Board Diagnostics) and the Danish inspection and maintenance
programme.
For each year, the deterioration factors are calculated pr first registration
year by using deterioration coefficients and cut-off mileages, as given in
EMEP/EEA (2009), for the corresponding layer. The deterioration coefficients
are given for the two driving cycles: ”Urban Driving Cycle” (UDF)
and ”Extra Urban Driving Cycle” (EUDF: urban and rural), with trip speeds
of 19 and 63 km pr h, respectively.
Firstly, the deterioration factors are calculated for the corresponding trip
speeds of 19 and 63 km pr h in each case determined by the total cumulated
mileage less than or exceeding the cut-off mileage. The Formulas 3 and 4
show the calculations for the ”Urban Driving Cycle”:
8') = 8 ⋅ 07& + 8 5$ 6
8') = 8 ⋅8
+ 8 5$ 6
where UDF is the urban deterioration factor, UA and UB the urban deterioration
coefficients, MTC = total cumulated mileage and UMAX urban cut-off
mileage.
In the case of trip speeds below 19 km pr h the deterioration factor, DF,
equals UDF, whereas for trip speeds exceeding 63 km pr h, DF=EUDF. For
trip speeds between 19 and 63 km pr h the deterioration factor, DF, is found
as an interpolation between UDF and EUDF. Secondly, the deterioration factors,
one for each of the three road types, are aggregated into layers by taking
into account vehicle numbers and annual mileage levels pr first registration
year:
')
(
)
∑
')
,
=
(
)
,
= (
)
∑
')
⋅ 1
,
=
(
)
,
⋅ 1
⋅ 0
,
,
where DF is the deterioration factor.
For N2O and NH3, COPERT IV takes into account deterioration as a linear
function of mileage for gasoline fuelled EURO 1-4 passenger cars and light
duty vehicles. The level of emission deterioration also relies on the content
of sulphur in the fuel. The deterioration coefficients are given in EMEP/EEA