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ELECTRONIC STABILITY PROGRAM (ESP)
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1.2 WORKING OF ESP
During normal operating conditions the ESP
controller will be monitoring the inputs made by
the driver through the steering wheel brakes and
accelerator pedals. It will also be monitoring the
vehicles response to these inputs through wheel
speed sensors and a yaw rate sensor.
The driver inputs are used by the system to
understand where and how the driver intends the
vehicle to manoeuvre. Using the wheel speed and
Yaw rate sensors the system calculates how the
vehicle is actually manoeuvring, and by
comparing the driver’s intentions with the actual
vehicle response it determines if it has to
intervene to maintain the vehicle on its intended
path.
The TCS part of ESP reacts to the vehicle
spinning one or more of its driven wheels. When a
wheel breaks traction and spins the drive force is
lost. The driver cannot accelerate, and the vehicle
stability is affected. The TCS is able to counter
this via 2 control strategies; firstly it can brake the
spinning wheel reducing the drive torque being
delivered at that wheel. By preventing the drive
torque from escaping at the spinning wheel more
torque will be delivered to the wheel which is free
to rotate. If all driven wheels are spinning or the
level of torque being delivered to the wheels is so
high it cannot be controlled by the brakes only the
system will reduce the engine torque to a level
that can be transmitted to the road.
The ESP is a development beyond the TCS and
reacts when it detects that the vehicle is starting
to skid (under steering or over steering).
ESP: Drive Modes MT Vehicle
Drive Modes is an innovative feature associated
can choose the vehicle dynamics as per driving
requirements for comfort, safe and sporty drive.
This feature, which is associated with engine and
seven
Other systems in the vehicle, offers the optimum
blend of performance, refinement, fuel economy
and Excitement to the driver, Drive modes are
selected through the Rotary Switch. The switch
will have different drive modes namely Auto,
Dynamic, Off Road and Comfort.
A. Normal Mode:
B. Wet Mode:
C. Rough Road Mode:
Rough Road Mode optimizes the vehicle behavior
for driving over rough road or other unyielding
obstacles. Such condition causes wheels to be
unloaded or to lift off the ground, causing a risk of
them to spinning up. This mode is focused to
improve
grip
and
vehicle
composure,
predominantly when wheels may be up against
steep obstacles and the vehicle is also going up
on inclined surface or rough roads, torque
optimization is specifically tuned for this condition.
Braking performance is also tuned to support
Rough road surfaces as compared to other drive
modes, it also benefits in to better stopping
distance and pedal feel for Rough Road surfaces.
The EMS internal calibration and ABS/ESP
operation modes change as per user selected
drive modes as
Described in Table below:
Visual Indication of Drive Mode selection:
The EMS and ABS/ESP will receive the switch
status on CAN and after reaching the required
drive mode,
These ECUs will send drive mode state signal to
the IPC, BCM and rotary switch to perform
functions as Described below:
1. Instrument Panel Cluster and Infotainment
system: will display the current drive mode
2. The rotary drive mode switch: It will give the
appropriate function ON LED activation to
indicate the Mode change.