1. Proposal for aerodynamic options
WLTP-DTP-LabProcICE-187
The vehicle shall be tested 3 times (3 coastdowns, 3 CO2-tests) to define the maximum bandwidth for CO2 values
TML without aerodynamic options
TMH aerodynamic without aerodyn. options and worst case
intermediate values for individual options to be calculated and added to TM CO2 value
extrapolation within a certain range should be possible
mass
CO2
TML
TMH
Aerodyn. worst case
DCO2
Aero CO2
individual values
for each option
Bandwidth of individual vehicle
No aerodynamic
options installed
TM CO2
Aerodyn. best case
C.Proposal : Aero. best instead of no aero. Options.
Concern to extrapolation, since aero dynamic parts may be influenced together, then extrapolation make some error.
No aerodynamic
options installed TM
C.Proposal : Road Load with ‘Best Aero‘ & ‘Weight with no aero.‘
This road load is possible to obtain by correction with wind tunnel & chassis dyno data, or coasting down. Then every intermediate data can be obtained by interpolation.
Aerodynamic options add weight to the vehicle, therefore TML measurements
have to be carried out without any options
AUDI, M. Bergmann

2. Consideration
CO2 by aerodynamic parts is adjusted by extrapolation method.
It is assumed that each aerodynamic part has fixed number of CO2 impact by interpolation.
However each aerodynamic part may affect each other (e.g. very close position).
In this case, extrapolation has some risk to under estimate the actual CO2 impact.
But interpolation can guarantee the best & worst case at least. So even if over or under estimation occur, it is within best & worst.
Integration of each aerodynamic data always equal to the aerodynamic gap between worst case and no aerodynamic parts? … No guarantee.