Efficiency of the alternator

[KIPAteel]

Hello,

I have question concerning the value for the alternator efficiency. Is this an average of the efficiencies of an IP-Family or is it based on the test vehicle itself?
And what is meant by the "Average alternator efficiency"? Is it the average over the WLTP cycle?
Additionally if this value can not be determined, can the default value of 0,67 be used?

Thanks in advance for your help.

[MaikeruJon]

My thoughts:

1. Surely the values for the alternator will be those relating to the alternator on the vehicle from which the rest of the data entered in the given CO2MPAS file were obtained?
2. Alternator efficiency is covered in ISO 8854. There we can find an explanation for calculating the weighted efficiency of the alternator. There is no mention there of 'average efficiency', though, only 'weighted efficiency'.
3. "Additionally if this value can not be determined, can the default value of 0,67 be used?" Well, yes. Is that not the defintion of a default value? "Default: a preselected option adopted by a computer program or other mechanism when no alternative is specified by the user or programmer."
   HTH

[dimitriskomnos]

Dear @KIPAteel and @MaikeruJon,

If you know the alternator efficiency of the specific vehicle being tested,
which the supplier of the alternator should be able to provide,
and if the Type Approval Authority can verify this value,
then you should you insert it.
For a CO2MPAS simulation it is essential to provide a value as accurate as possible.

In case this is not feasible,
you may use the default value which is the fixed value for the WLTP (Sub-Annex 6 Appendix 2).