The agenda was adopted with the addition of the input from Mr. Adam: MVC-05-02.
The chair raised the problem of the mandate extension, as it is foreseen that the group should table a draft by December 2015.
Does any potential / practical issue exist with ISO 7638 dimensioning (UN R13 paragraph 220.127.116.11.2. also to be reviewed)?
Mr. Adam presented the Part 2 of his contribution per document MVC-05-02.
The experts had a debate on the trends of power consumptions: EBS decreased the levels of current, while the forthcoming electric steering function may increase the necessary power. Need to note that the draft amendments to take into account ACS connectors (7638).
There was a debate on whether to limit the current generated to the other vehicles. It was suggested to inspire from what was adopted by the task-force on trailer electric steering system.
What consumes the most current: self-check, braking on slippery surface, number of valves?
Proposal to put labels on the vehicles about compatibility of different vehicles. Yet it was recalled that this solution should be avoided due to the poor durability of the labels.
Technical principle: Point to point ISO 11992 connection between two successive vehicles in the combination
M. Adam (CLEPA – WABCO) presented the 1st part of his document MVC-05-02. ISO 7638 connector, with 7 pins, 2 of them belong to the CAN communication network, according to ISO11992. Point-to-point communication between 2 nodes. If man adds an additional vehicle, then there is an additional node. Mr. Adam was of the opinion that ISO contains all the necessary information for the interest of the MVC group. No need for additional requirement into UN R13.
Mr. Manz (CLEPA/BPW) pointed out:
The experts found opportune to change along the text of the regulation, the word “motor vehicle” or “tractor” into “towing vehicle”.
The question was raised about a combination with several trailers, each with a router, and where the 1st router would fail. Would the 2nd trailer receive the number 1?
According to M. Adam, there must be an electronic control line in every towing vehicle in a MVC.
Type 0 requirements (value of deceleration)
MP (CLEPA/BPW) was of the opinion that the dolly should be considered as a truck for semi-trailer because that permits the combination “dolly + semitrailer” to have a braking capability average of 50% (i.e. 45 + 55%). Should the dolly take only 50%, then the combination would take less than 50%.
BS (CLEPA/VBG) presented some slides (MVC-05-03 and MVC-05-04 – summary of the Eindhoven study) showing dolly braking performances in case of high braking conditions. There was a debate on the load transfer in case of a combination of tractor/dolly/semi-trailer (Case D). In case of braking, one part of the load of the semi-trailer is transferred to the tractor (via the dolly). The experts wondered whether the dolly could take 50% of the braking. The chair feared that a too low value for the dolly could generate a jack-knife situation.
Compatibility bands for dollies
The group decided to postpone to the next meeting the decision this item (central axle trailer vs. tractor/semi-trailer combination).
The group agreed to review the document paragraph by paragraph.
There was a debate on the necessity to add a definition of a “towing trailer”: there are 2 types of towing trailer i.e. semi-trailer with 5th wheel, and extended chassis with 5th wheel. Agreed to delete the reference to “this regulation”.
Definition of dolly: Debate on the possible restriction of such definition: it could prevent adding some future new technologies. Agreed to change the definition: “dolly” means a towing trailer designed for the sole purpose to tow a semi-trailer.” Agreed to make the definition of a dolly as a sub-definition of towing trailer.
Paragraph 5.1.3.: adopted
Paragraph 18.104.22.168. to 22.214.171.124.1.: adopted. Mr. Heim pointed out that there use of “coupling head” is unclear, since it is usually understood as a pneumatic connector, while it is here used as both pneumatic and electric. The group agreed to keep this issue in head.
Paragraph 126.96.36.199.: adopted
Paragraph 188.8.131.52.3.: adopted
Paragraph 184.108.40.206.4.: question of the meaning of “highest”. There was a debate on the interpretation of the last sentence of the paragraph. The group agreed to flag this sentence and inquire on the origin of the change. The 1st sentence may be interpreted such that if there is in the chain a vehicle with only pneumatic brake/only electric brake, then the combination may have the wrong design and the relevant action must be taken. MMrr Heim and Adam volunteered to dig in the working documents and the history of the document for finding the meaning and purpose of the paragraph.
Conclusion: M. Heim and M. Adam to provide explanation on the necessity of the proposed paragraph.
Paragraph 220.127.116.11.: the group tried to secure that the hoses and cables are always provided. PT proposed a simplified wording (MVC-05-05):
[The meeting report contains proposed sketches for vehicle combinations.]
The group adopted the PT proposal, as amended, together with the sketches. The group acknowledged that there is still room for grammatical improvement, and that the sketches could be placed either as an explanation in the justifications to the working document, or as a new annex of the regulation.
Paragraph 18.104.22.168.: the group acknowledged that the word “towing” was not present in the current text of the regulation, hence should not be deleted.
Paragraph 22.214.171.124.1.: “one cooker is enough in the kitchen”, i.e. two controllers in a control loop could lead to unstable situations. Hence the group agreed to keep the requirement of one unique coupling force control.
Conclusion: proposed change adopted.
The group had no time to continue the revision of the document further than paragraph 126.96.36.199.1.