WABCO TAILGUARD, Описание системы

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System and function System and function
5 System and function
This chapter provides you with a general overview of function and structure of
the systems.
With TailGUARD for Truck and Bus there are the following options for
autonomous braking:
Braking via separate valves:
Safe operation of the braking system is ensured by the design with a two-way
valve if the system is in a fault-free state.
Braking via a prepared interface for TailGUARD:
The system does not have direct access to the vehicle brake and sends
braking requests to the vehicle’s braking system via a TailGUARD interface.
This function will be available in some towing vehicles from 2017.
To avoid any accidents, observe the following safety instructions for
vehicles with braking intervention through TailGUARD:
„
Vehicles with a prepared interface for TailGUARD: TailGUARD may not
brake if the vehicle’s EBS system has a fault.
5 .1 Functional description
TailGUARD is activated by shifting into reverse gear.
The ultrasonic sensors and valves are tested for proper function and the
TailGUARD system's readiness for operation is signalled to the driver.
If an object is identified while reversing and the distance becomes less than
the configured stopping distance, the vehicle will be braked for 3 seconds
before the brake is released again. The stopping distance can be configured via
parameters (between 50 and 200 cm).
While the signal for braking is being given, another signal is available to avoid
simultaneous acceleration of the vehicle. This signal can be used to reset an
accelerator pedal to neutral or to shift a transmission to neutral.
!
This signal must only be used to trigger vehicle functions that prevent
acceleration of the vehicle. The signal must not be used to trigger a brake
intervention.
At speeds above 9 km/h the deceleration defined for TailGUARD may not
suffice to stop the vehicle within the configured stopping distance.
If the vehicle moves backward at 9 km/h or more, TailGUARD triggers short
brake pulses to notify the driver of the excessive speed. TailGUARD here
regulates the speed down to 7 km/h. If these warning brake actions are ignored
and the speed continues to increase, the system is switched off at 12 km/h.
Following an autonomous braking procedure, the driver can start driving again
and continue to reverse.