MVC-01-04
BRAKE SYSTEMS IN
MODULAR VEHICLE
COMBINATIONS
Christoph Adam
02. July 2014
WABCO Confidential and Proprietary
1
MVC-01-04
MODULAR VEHICLE COMBINATIONS
Modular Vehicle Combinations (MVCs) combinations with more than one trailer.
Examples:
truck + 2 centre axle trailers
tractor + semi trailer + full trailer
tractor + 2 semi trailers
truck + dolly + semi trailer
Kind of combination and number of trailers is not limited !
Large number of variants
WABCO Confidential and Proprietary
2
MVC-01-04
MODULAR VEHICLE COMBINATIONS
 The use of MVCs is strictly limited in many countries e.g. in
member states of European Union as these combinations often
exceed the maximum permissible values of weights and/or
dimensions.
 Exemptions to these limits like European Modulator System
(EMS) based on 96/53/EC Article 4 , 4 (b) permit the use of
MVCs on national basis under certain conditions.
 Since some years an increased use of MVCs is under
discussion. Among other open questions a gap in UNECE R 13
was identified:
There are no requirements for type approval and performance of
brake systems for vehicles in MVCs.
MVC in Regulations
WABCO Confidential and Proprietary
BRAKING SYSTEMS FOR
MODULAR VEHICLE COMBINATIONS
MVC-01-04
To close this gap, a small working group (Mercedes Benz Trucks,
Knorr-Bremse, Haldex, TÜV Nord and WABCO) discussed this
issue and drafted a proposal, which was presented by Clepa at
GRRF No 66 as informal document 66-08.
It is based on an approach as follows:
1. Current level of safety within the braking systems of MVCs
shall be retained in all combined vehicles and combinations.
2. Technical compatibility between new and old vehicles should
be retained as far as possible. This should fit to all possible
combinations, if possible.
3. New requirements for motor vehicles should be avoided as far
as possible.
4. New requirements shall be introduced for towing trailers.
Background of informal document GRRF 66-08
WABCO Confidential and Proprietary
BRAKING SYSTEMS FOR
MODULAR VEHICLE COMBINATIONS
MVC-01-04
1. Current level of safety within the braking systems of MVCs
shall be retained in all combined vehicles and combinations
Measures and requirements regarding automatic braking of a
succeeding trailer  functionality of trailer control valve, usually
mounted on the motor vehicle, needs to be fulfilled by towing trailers
•
Pneumatic and electric control and electric signals need to be
transferred through the entire combination – in both directions !
Source: ISO 11992-2
•
Some details to keep current safety level
WABCO Confidential and Proprietary
MVC-01-04
BRAKING SYSTEMS FOR
MODULAR VEHICLE COMBINATIONS
Example:
Transmission of electric signals in possible combinations in
vehicles with / without electric control line. As safe as today ?

Very
complex !
Conclusion:
All towing trailer shall be equipped with an electric control line !
Pragmatic approach to reduce complexity of requirements
WABCO Confidential and Proprietary
PROPOSED AMENDMENTS TO UNECE
Regulation No 13
MVC-01-04
Definitions
•
New paragraphs 2.42. and 2.43. “towing trailer” and “dolly”
Requirements
1. General
•
Amend “power driven vehicle” where necessary to “power driven vehicle or towing
trailer” throughout the regulation
•
•
Yellow trailer warning signal via PIN 5 of ISO 7638 plus CAN message
•
Clarifications to include towing trailers
Red trailer warning signal of every trailer in an MVC (CAN message) to be
displayed
2. For motor vehicles authorized to tow more than one trailer
•
Parking brake shall activate the trailers braking system
New definitions, clarifications, requirements for motor vehicles
WABCO Confidential and Proprietary
PROPOSED AMENDMENTS TO UNECE
Regulation No 13
MVC-01-04
Requirements
3. For towing trailers
•
ISO 7638 connector (or ACV) on front and rear side, reduced cable cross section
not permitted (to avoid voltage drop)
•
•
New paragraph 5.2.2.24. for towing trailers
•
Not to be used with motor vehicles without pneumatic control line acc. to 5.1.2.1.3.
 automatic braking of towing trailer required
•
In analogy to requirements of motor vehicles
Pneumatic and electric control line acc. to 5.1.3.1.2. required (standard for most
trailers today)

Remaining brake performance of a towing trailer 50 % in case of a failure in the brake
system of a succeeding trailer

Automatic braking in case of a failure in one of the pneumatic connecting lines

Activation of the trailers brake alone is not permitted

Parking brake with spring brakes
Transfer of motor vehicle requirements to towing trailers
WABCO Confidential and Proprietary
PROPOSED AMENDMENTS TO UNECE
Regulation No 13
Requirements
3. For towing trailers
•
•
•
Parking brake shall activate brakes of succeeding trailers
Same value of control pressure for all trailers in an MVC
A dolly shall be considered as a centre axle trailer
WABCO Confidential and Proprietary
MVC-01-04
PROPOSED AMENDMENTS TO UNECE
Regulation No 13
MVC-01-04
Requirements
4. In Annexes
•
•
Annex 2: documentation adapted

Motor vehicle authorized to tow more than one trailer

Trailer authorized to tow trailers
Annex 6

•
Annex 7

•
Specific method how to measure the response time of towing trailers
Testing in analogy to requirements of motor vehicles
Annex 17: Specific requirements to check functionality of electric control lines in
towing trailers

Check of parameters at front and rear connector of a towing trailer
Large number of variants
WABCO Confidential and Proprietary
MVC-01-04
WABCO Confidential and Proprietary