Title Arial 24, Bold, Shaded, KB-Blue

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Document No. EVSC04-05
GRRF Ad-Hoc Working GroupElectronic Vehicle
Stability ControlTrailers25 26 November
2004
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Trailer Induced
Roll Over
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UK Roll Over Statistics - Heavy Commercial
Vehicles
700
600
500
400
Number of Roll Over Accidents
300
200
100
0
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Causes of Roll-Over
Driver misjudgement of speed road conditions
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Causes of Roll-Over
Collision avoidance
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Considerations
It is NOT possible to prevent ALL roll overs

• Vehicle is Tripped

• Excessive over speed

Many roll overs are the result of loss of
concentration and minor misjudgement of road
conditions
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Primary Roll Over Factors

• Effective track

• Position of load

• Centre of gravity

• Vehicle speed

• Radius of turn

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Secondary Roll Over Factors

• Roll stiffness

• Torsional chassis stiffness

• Road camber

• Load shift

• Tyre Pressure

• Fifth wheel coupling

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Trailer ABS EBS Functionality
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Conventional Semi-Trailer Anti-Lock Braking System
2S/2M or 4S/2M Independent Control
ECU
ISO 7638 (5 Pin)
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Semi-Trailer Electronic Braking System
2S/2M or 4S/2M Independent Control
ISO 7638 (7 Pin)
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Control Input Variables
Parameter
Trailer ABS
Trailer EBS
X
Wheel speed signals
Driver demand - pneumatic
Driver demand - CAN
Brake chamber Delivery pressure
Reservoir pressure
Axle load / bogie load
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Functionality
Function
Trailer ABS
Trailer EBS
Anti-Lock control
Load sensing
Auxiliary Outputs
Auxiliary inputs
Automatic brake applications
Data communications
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Roll
Stability
Function
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Objective
Reduce the Incidence of Trailer Induced Roll-Over
Lateral Acceleration Sensor Roll Stability
Software

Trailer EBS
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Tractor / Trailer Compatibility
Trailer equipped with EBS RSF
Towing Vehicle Trailer Specification
Functionality No ISO7638 (no ABS) No
ABS - LSF - RSF ABS Full
functionality EBS Full
functionality EBS ESF Full
functionality
Full functionality maintained when connected to
any towing vehicle equipped with an ISO7638
power supply (5 or 7pin)
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Control Line Signal Priorities
No Brake Demand Trailer EBS defines controls
the pressure at the brake chambers Pneumatic or
Electric Control Line Signal If the signal would
produce a brake chamber pressure higher than the
pressure defined by the trailer EBS the pressure
associated with the control line signal will be
generated. If the signal would produce a brake
chamber pressure lower than the pressure defined
by the trailer EBS the EBS defined pressure will
be generated.
This principle applies irrespective of whether
the brake demand is generated by the driver or
the towing vehicle ESP system
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Conclusions
Trailer Roll Stability is effective when
connected to a towing vehicle via the ISO7638
connector. Compatible with all ABS, EBS
EBSESF towing vehicles
Installation of ESP-RSF on the tractor or RSF on
the trailer is not a replacement for good driving
practice.
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Current System Applications
YES Air suspension only
No Not necessary
YES Air suspension only
YES Air suspension only
No Not necessary
No
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Compatibility of Mixed Combinations
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GRRF Ad-Hoc Working GroupElectronic Vehicle
Stability ControlTrailers25 26 November
2004