Discussion on document ACV-02-09:

Problem 1 : has been incorporated into the reworked document.

Problem 2: The standard ISO 7638 is technically not up-to-date, this could be addressed either via ISO or via GRRF. It is a question of technical hardware on the vehicle; there is no pin to connect the red wire from the truck, this goes via the CAN bus. Assuming that all trucks have technical equipment then the other concern is one of philosophy.

The group considered that R13 is clear enough today but that all manufacturers have to come to an agreement on how to use it. This group has to work independently from the decision by the manufacturers and should start the discussion in GRRF. However, this group will wait with that until it has a complete overview.

Problem 3: This problem addresses the terminology of this group. The group has to make a clear definition that it is impossible to make dead ends or loops.

The group looked at the sketches of document ACV-02-10.

Proposal: To allow only one connector on the truck and one connector on the trailer to avoid dead ends and reflections in these dead ends. The group proposes a split of the flex cable. Today, some manufacturers produce trucks with two 7-pin connectors. Or the second connector is added afterwards. This can cause problems to the CAN bus. The proposal could be that attachment of the towing hitch can only happen if the other connector is de-coupled, as we must always have ABS. In other words, only one connector is allowed to be active at any one time. JOST is to draft a first text for a proposal.

Problem 4: Solved given our solution for problem 3.

Problem 5: There is a standard on functional safety, ISO26262. A development process fulfilling that standard would, according to the representative of VBG, with high certainty deliver products and systems that fulfill the requirements in R13 Annex 18. As regards the current proposals, the handling of the connection of the compressed air for the braking of the towed vehicles are already subject to requirements of the R13 Annex 18 if that connection is handled by a complex electronic system. In the case of the VBG MFC coupling, the control system is reviewed as a separate part. The review report is thus a document to be included in the Annex 18 review of the complete braking system.

The reference to R13 Annex 18 in the proposal for change to R55 is only for the safety of the mechanical coupling, i.e. the realization of the requirement for a double locking device. The VBG MFC coupling is the first coupling having the mechanical connection controlled through a complex electronic system. Knowing the existence of R13 Annex 18, the representative of VBG reckons that it is good to require such a review with respect to the handling of the mechanical coupling. I.e. there is no need for the braking expert to know that there is a requirement for a review complex electronic system controlling the mechanical coupling. However, there is a requirement for the braking expert to know how the braking system is realized.

A good technical assessment of the system is necessary. The manual situation is no problem but with a control system judged to be complex, a report of the assessment is needed but nothing more. In R55 something is needed about remote opened coupling systems, such as that it must have an indicator, a double locking device and other so as to fulfill a certain safety level.

The reason why we have so many references to ISO 7638 lies in the fact that signals are not defined in R13. Only 1 or 2 references are really needed. Annex 18 is not the way to ensure that a certain safety level is reached, something must be done in R55.

When the mechanical part is closed and there is some loss of connection then a signal in the cab is needed. As not all solutions include that, we may need something specific.

Conclusion : problem 5 is solved if the reference to annex 18 is deleted.

Editorial comments on document ACV-02-09 were considered ok.

None needed to be discussed.