CoastdownVH&C Onboard Anemometry Ford Motor Company North America WLTP-11-14e

CoastdownVH&C Introduction and Status The onboard anemometry method has been developed and assessed through the Annex 4 Taskforce as a method of road load determination At the WLTP IWG #10 in Stockholm the methodology was decomposed and the validation tests and approach were agreed upon by the IWG Open issues following the IWG #10 meeting: 1.Updates to the WLTP language 2.Presentation of final proposal for IWG #11 (Geneva)

CoastdownVH&C Updates to WLTP Language The current WLTP language was reviewed in depth and recommendations were supplied to the Annex 4 task force Feedback from the task force was incorporated into the following slides to address the following concerns: –Wind speed tolerances for contracting parties –Text referencing the SAE J2263 text from which the WLTP language was derived –Flexibility to request the approval of additional anemometer locations for testing –Aerodynamic corrections required to address aerodynamic impact of the anemometer for all anemometer test configurations

CoastdownVH&C Current GTR text: Wind conditions using on-board anemometry For testing with an on-board anemometer, a device shall be used as described in paragraph of this Annex. The overall average wind speed during the test activity over the test road shall be less than 7 m/s with peak wind speeds of less than 10 m/s. In addition, the vector component of the wind speed across the road shall be less than 4 m/s. Contracting Parties may choose to permit more relaxed wind speed limits for coastdown test data using on-board anemometry from test facilities that are generally free from wind obstructions and thus providing stable wind conditions. In this case, the limits shall correspond to an overall average wind speed during the test activity over the test road that is less than 10 m/s with peak wind speeds of less than 14 m/s. In addition, the vector component of the wind speed across the road shall be less than 5 m/s. Recommendation: Remove the contracting parties option Wind conditions using on-board anemometry For testing with an on-board anemometer, a device shall be used as described in paragraph of this Annex. The overall average wind speed during the test activity over the test road shall be less than 7 m/s with peak wind speeds of less than 10 m/s. In addition, the vector component of the wind speed across the road shall be less than 4 m/s.

CoastdownVH&C Recommendation: Add language that references SAE J2263 as the source material: Coastdown method with on-board anemometry Fundamentally based off of SAE J2263 DEC2008 text, deviations have been applied as stated in the sections that follow Warmup and instrumentation for on-board anemometry The vehicle shall be warmed up and stabilized according to paragraph of this Annex. Calibration of instrumentation will take place during this time. The anemometer shall be calibrated by means of operation on the test vehicle where such calibration occurs during the warm-up for the test. Current GTR text: Coastdown method with on-board anemometry The vehicle shall be warmed up and stabilized according to paragraph of this Annex. Calibration of instrumentation will take place during this time Additional instrumentation for on-board anemometry The anemometer shall be calibrated by means of operation on the test vehicle where such calibration occurs during the warm-up for the test.

CoastdownVH&C Current GTR text: Vehicle coastdown procedure Vehicle coastdown shall be conducted as specified in paragraph above with an on-board anemometer installed on the vehicle. A minimum of ten runs shall be made in alternating directions; five runs in each direction. Wind-corrected coastdown data must satisfy the statistical accuracy requirements as specified in paragraph above. The anemometer shall be installed in a position such that the effect on the operating characteristics of the vehicle is minimized. The anemometer shall be installed according to (a) or (b) below: (a)Using a boom approximately 2 metres in front of the vehicle’s forward aerodynamic stagnation point. (b)On the roof of the vehicle at its centreline. If possible, the anemometer shall be mounted within 15 cm. from the top of the windshield. In the event that position (b) is used, the coastdown results shall be analytically adjusted for the additional aerodynamic drag induced by the anemometer. The adjustment shall be made by testing the coastdown vehicle in a wind tunnel both with and without the anemometer installed (same position as used on the track), where the calculated difference will be the incremental drag coefficient (C_d), which combined with the frontal area can be used to correct the coastdown results. Recommendation: GTR text to include anemometer position flexibility and aero correction requirement for all anemometer locations: Vehicle coastdown procedure Vehicle coastdown shall be conducted as specified in paragraph above with an on-board anemometer installed on the vehicle. A minimum of ten runs shall be made in alternating directions; five runs in each direction. Wind-corrected coastdown data must satisfy the statistical accuracy requirements as specified in paragraph above. The anemometer shall be installed in a position such that the effect on the operating characteristics of the vehicle is minimized. The anemometer shall be installed according to (a) or (b) below: (a)Using a boom approximately 2 metres in front of the vehicle’s forward aerodynamic stagnation point. (b)On the roof of the vehicle at its centreline. If possible, the anemometer shall be mounted within 15 cm. from the top of the windshield. (c)Other mounting positions may be requested by manufacturers if equivalency to position (a) is exhibited and approved. The coastdown results shall be analytically adjusted for aerodynamic drag induced by the anemometer. The adjustment shall be made via corrections determined through aerodynamic modeling or in a wind tunnel using the incremental C_d*A from testing with and without the anemometer present.

CoastdownVH&C Conclusions and Status Referencing the SAE J2263 onboard anemometry test method is strongly recommended as it is the basis of the WLTP text Updates to the GTR text are pending approval by the Annex 4 task force and greater WLTP IWG Remaining items addressing Annex 4 requests: –Access to the SAE J2263 text to review similarities for the reference –Access to a working sample program for the test method to review the internal calculations and applicability –Explore the aerodynamic impact of the boom mounted anemometer test method and new requirement to correct for the aero drag for all anemometer locations Adoption of the methodology and proposed text is recommended