Mr. Schmitt provided an overview of document TF-BTA-6-03. He explained that the intention of the document was to summarize the ideas that were derived in the 5th meeting and that industry had been tasked with drafting a workable proposal. However, to have a good basis for discussion, i.e. having a chance to compare different options, the chair had suggested keeping this document as separate document.
Mr. Gehring wondered were the dimensions of the corner gauge came from. Mr. Schmitt responded that the original idea developed in the 5th meeting was to use the same pendulum as used in the US CFR (Code of Federal Regulations) 49 part 581. The dimensions of the surface of this pendulum were considered. Also, on request of Mr. Gehring it was clarified that, in this proposal, the contact of the vehicle fascia with the new corner gauge should be at the centerline of the gauge rather than the complete surface to avoid that e.g. extended wheel arches may be considered at bumper corners.
In the discussion it was agreed that wheel arches could under certain conditions be excluded from the test area, provided that they do not widen the vehicle body too much (such as e.g. with free-standing wheel arches). In this context the wheel arches of the Jeep Wrangler were mentioned, as such designs should indeed be included in the assessment.
Mr. Broertjes explained that the EC in principle could agree with the document prepared by industry. However, he suggested extending the height of the corner gauge assessment area to at least the height of the legform impactor (75 mm to 1003 mm above the ground) (see document TF-BTA-6-04; it was noted that the upper height needs to be corrected in this document). Also, the upper and lower bumper reference lines should be added to assure that the front is tested. Mr. Zander wondered why the UBRL and LBRL should be added. He explained that the reference lines cannot be marked with the corner of the bumper; this may be difficult. Mr. Schmitt responded that the reference lines may be needed to avoid that the outside mirrors are the corners of the test area since they can be contacted with the upper end of the legform impactor at most cars. However, he would clearly not consider the mirrors as vehicle front. In addition, the reference lines can be marked in most cases without problems and they are already in use today.
On request of Mr. Zander, Mr. Broertjes also clarified that the EC wishes to have the test area widened as much as possible and therefore wishes to omit the clause that allows tests only to be conducted 66 mm inside of the bumper corners.
Mr. Zander then pointed out that a pragmatic solution may be to not use corner gauges but e.g. a stick instead of the current planes – this would simplify the proposal and follows the current procedure. Mr. Kinsky reminded that group that this is in line with the original ideas of industry. However, the group had later reflected positively on the approach to consider the assessment area of structural interaction as is applied for the US bumper testing, as usually the outer bumper fascia follows closely the rigid structure bumper beam in that area, as covered by it.
Mr. Takagi presented the proposal of Japan (documents TF-BTA-6-05 and TF-BTA-6-06) and explained that in principle, Japan also can agree with the idea of corner gauges and may consider the other proposals. However, Japan noted that for different vehicle shapes (e.g. narrow front nose but wide front bumper) the widest area is to be assessed, which was not sufficiently safeguarded in all proposals presented, due to certain limitations resulting from the language used.
Mr. Zander presented document TF-BTA-6-07 assessing the proposals already made and concluding that none of them seems to work reliably. Therefore, he explained that BASt would rather insist on considering the bumper test area as defined by Euro NCAP. Mr. Zander then also showed some examples where the bumper beam extends outside the bumper corners as defined via contact points on the vehicle surface. He concluded that the assessment of the bumper beam definition as used by RCAR (Research Council for Automobile Repairs) could serve for the purposes of the TF-BTA.
Mr. Kinsky added that also examples are available from industry where the bumper beam does not extend the test area defined by the bumper corners. Unfortunately, these data cannot be shared officially with the whole group, but may be shared on a bilateral basis with all interested experts.
Mr. Broertjes asked what would be the preference of the US: using the bumper beam definition or using corner gauges to define the bumper corners. Mr. Martin replied that probably both might serve the needs of the US. However, he would probably consider the bumper outer contour, as this is the factual contact point with the pedestrian. Mr. Gehring suggested that in fact the bumper beam is considered to be the injurious part, caused by the hard structure. Mr. Martin then wondered whether this would mean that no other parts would cause injuries. Finally, it was agreed that other vehicle parts and fascia could cause injuries as well. However, that the outer contour can be modified easily and therefore should not be the only criterion. Mr. Gehring further explained that Euro NCAP uses both: the width of the bumper beam and the 60° bumper corners, and finally tests the wider of the two test areas.
Mr. Roth brought up that connecting the test area to one vehicle part could be design restrictive. Also, the proposal of BASt was deemed lacking the scientific proof whether or not the outer part of the bumper beam is indeed creating an additional risk for pedestrians. Finally, he noted that detailed data has been provided in the context of the Task Force showing that none of the existing impactors is reliably capable of being used on oblique surfaces.
It was then intensively discussed how the bumper test area could be defined. Mr. Carroll finally proposed to first define which are the injury causing parts and then to decide which test area needs to be chosen to address this. Finally, it may be the case that this area may not be tested due to the limitations of the impactors.
Discussion returned to the need of a 66 mm allowance inside the test area. Industry representatives explained that a certain structure as well as a certain interaction with this structure is needed to control the behavior of the impactor. In addition, the intention originally was to assess the test area, which can be ‘guaranteed’ in terms of testing stability with an offset of half a legform diameter. The same logic applies to the headform test, and in all cases testing closer to the borderlines causes the risk of glancing blows. For Euro NCAP, this may be of less importance since it just influences a rating. However, for mandatory legislation it is important to make sure that the compliance tests provide reliable and stable results. Mr. Martin added that for the US it is important to have testing (as well as compliance rating) be conducted reliably. However, obviously there are vehicles where the 66 mm are not needed and do not influence the test results and for those vehicles it should be considered to delete the allowance. Mr. Takagi supported the need of the allowance. Mr. Broertjes wondered whether it could be decreased to the hard parts of the impactor, which means a diameter of 84 mm for the FlexPLI and 70.5 mm for the EEVC legform impactor (i.e. the diameter divided by two, for the allowance area).
After some further discussion, Mr. Broertjes noted that finally a decision needs to be made by the contracting parties in Geneva. Therefore, he proposed to draft a proposal that can cover both, the new definition of the bumper corners and the consideration of the bumper beam. Discussions could then be held with the experts in Geneva, also allowing more interaction with Contracting Parties that are not participating in the Task Force on a frequent basis.
Mr. Martin wondered whether the whole front end could be considered as potential test area. At the time when the 60° bumper corners where defined they covered indeed the whole front. A new test tool, e.g. a pedestrian dummy, may allow testing the whole front in the future. Today, a tendency can be seen that the test areas are defined according to the impactor abilities. Several attendees noted that this may need more detailed research in the future. Mr. Broertjes further pointed out that the EC is looking for a quick solution that avoids unwarranted narrowing of test areas as result of certain vehicle designs.
Mr. Takagi noted that Japan had not yet had the time to assess BASt’s proposal. However, if the idea will again be brought up, for instance at the December 2014 GRSP session, Japan will consider it further.