search

JRCSTU / CO2MPAS-TA

EU's Type-Approving vehicle simulator predicting NEDC CO2 emissions from WLTP
https://co2mpas.readthedocs.io/
European Union Public License 1.1
23 stars 13 forks source link

Re-running a DICE #24

Open ankostis opened 6 years ago

ankostis commented 6 years ago

We are opening this issue for public discussion on when it is allowed to re-run a DICE, and how. The two reasons for doing that are:

  1. to extend the Interpolation Family to Higher/Lower vehicles, and
  2. to correct WLTP data (corrupted or mistaken) or NEDC's CO2 declared-values.

(please reply below if you see is another reason)

In general we suggest to avoid re-dicing, because on every dice, the sampling decision must be respected (possibly re-testing the vehicle in WLTP/NEDC), and consequently, the verification-factors must be updated.

So far CLIMA has approved a single re-certification, based on reason no-1. That was a clear case involving a new physical WLTP test. For that, JRC implemented the --recertify feature of CO2MPAS in v1.7.3post0, which preserves the link between both runs, but only the last one is considered "ofrficial". Of course, re-dicing after the vehicle has been put in circulation would complicate things.

We have also forward requests regarding no-2 to CLIMA (errors in the inputs, with or without performing new physical WLTP-tests), and we will explain here the general outcome (criteria, rules applied).

ankostis commented 6 years ago

As a general note, there is no universal answer for re-dicing, every case is different. In order to understand every such case we need the following information:

  1. Which is the Interpolation Family ID involved; What was the CO2MPAS deviation and the random number from the DICE?
  2. Did the vehicle actually undergo a physical NEDC test? Do you still have the vehicle available?
  3. What was the "problem" requiring a fix?
  4. Would a possible fix affect the CO2MPAS deviation? (Up or down??)
  5. What do you want to change?
    • the declared values?
    • wltp series?
    • road-loads?
    • something else?

You should be aware that a possible fix still needs to be DICEd.
So in principle, the vehicle has to be available for a physical test before re-dicing.

And since it is CLIMA that decides, we suggest to always send an e-mail to CLIMA with the above questions answered, and JRC in CC.