operators_manual

brake pressure at all wheel ends to slow
the vehicle combination. The level of
braking application during an RSP event
will be proportional to roll risk.
A Real World Example of How the
RSP System Operates
Excessive speed for road conditions
creates forces that exceed the threshold at
which a vehicle is likely to rollover on a
higher-friction surface. The system
automatically reduces engine torque and
applies the service brakes (based on the
projected rollover risk) to reduce the
vehicle speed, thereby reducing the
tendency to roll over.
RSP Example
Yaw Stability
Yaw stability counteracts the tendency of a
vehicle to spin about its vertical axis.
During operation, if the friction between the
road surface and the tires is not sufficient
to oppose lateral (side) forces, one or more
of the tires can slide, causing the truck/
tractor to spin. These yaw events are
referred to as either "under-steer" (where
there is a lack of vehicle response to
steering input due to tire slide on the steer
axle) or "over-steer" (where the tractor's
rear end slides out due to tire slide on the
rear axle) situation. Generally, shorter
wheelbase vehicles (tractors, for instance)
have less natural yaw stability, while longer
wheelbase vehicles (straight trucks, for
instance) have greater natural yaw stability.
Factors that influence yaw stability are:
wheelbase, suspension, steering geometry,
weight distribution front to rear, and vehicle
track width.
Yaw Control
Yaw Control responds to a wide range of
low- to high-friction surface scenarios
including rollover, jackknife and loss of
control. In the case of vehicle slide (over-
steer or understeer situations), the system
will reduce the throttle and then brake one
or more of the "four corners" of the vehicle
(in addition to potentially applying the
trailer brakes), thus applying a counter-
force to better align the vehicle with an
appropriate path of travel. For example, in
an over-steer situation, the system applies
the "outside" front brake; while in an under-
steer condition, the "inside" rear brake is
applied.
A Real World Example of How Yaw
Control Operates
Excessive speed exceeds the threshold,
creating a situation where a vehicle is likely
to spin and jackknife. The Bendix
®
Yaw
Control system reduces engine throttle and
DRIVING - Brakes
Y53-6047-2HEN (03/18) 151
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