WLTP24 10 e CFD Report Status Report of

WLTP-24 -10 e CFD Report Status Report of New Issues TF –CFD* sub wg *CFD: Computational Fluid Dynamics method, method to simulate aero drag Sep. , 2018 Mayumi “Sophie” Morimoto (JASIC)

Background of CFD discussion/Status n Review of 22 nd WLTP IWG in April 2018 • Sub working group members requested to CPs/TAs and IWG to join the meeting. • Because of lack of resources, WLTP IWG decided to postpone the discussion of CFD sub working group until GTR 15 Amd 5 discussion finish. n During the CFD discussion on May • Even with WLTP IWG decision, some manufacturers strongly requested discussion even without TA/CPs, to make some proposals on Spring 2019. They also did not accept discussion between manufacturers within each regions. • Therefore, web meeting of CFD sub wg in UN level was held on 5 th Sep. n Status & Schedule • 2 meetings were held after April WLTP IWG. • Next meeting will be held at late November or early December 1/2

Discussion Points/Comments raised by members A. Certification criteria of CFD simulation model 2/2 • Most of the members request to delete current requirements/criterion and add more reasonable criterion and make text clear. • Some members have ideas on what to write on the text instead of current requirement. Those proposals will be discussed at next meeting. B. Certification demonstration/process of CFD simulation model • Whether to write in details or just write “Shall be discussed with responsible authority” is under discussion. C. Certification process of vehicle aero drag using CFD simulation model D. Re-certification criteria of CFD simulation model • Requested to define more clearly. This is also under discussion. E. Certification scope using CFD simulation model • There are comment to make specific family for CFD since R/L family is not relevant to CFD. F. Certification motivation using CFD simulation model *See WLTP-24 -10 e Appendix 1 for details. Technical discussions are on going in CFD sub-working group.

Thank you very much for your attention!