Date post: | 12-Apr-2017 |
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Engineering |
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ELECTRONIC STABILITY PROGRAM
The greatest safety invention after seat belts
What is ESP?
A computerized technology that improves a vehicle's stability by
detecting and reducing loss of traction
TRACTION
A physical process in which a force is transmitted across an interface between two bodies through dry friction
The grip of a tyre on a road
Factors affecting traction
Material composition of each surface Macroscopic and microscopic texture Normal force pressing contact surfaces Contaminants at the material boundary, i.e. lubricants and
adhesives Relative motion of tractive surfaces - a sliding object has less
traction than a non-sliding object Direction of traction - e.g., cornering, accelerating, and braking.
Importance of Traction
It allows for higher acceleration at cornering without wheel slippage
Contact of wheels with ground increase stability
History of ESP
First iteration in 1980 by BMW Mercedes steps in, in 1992 with supplier Bosch Toyota introduces Vehicle Stability Control (VSC)
in 1995 General Motors begins introduces ESP in 1997 European Union makes ESP mandatory in 2009
Basic Physical Principles
Tractive force
Brake pressure Lateral force
Adhesion force
Basic Physical Principles
Yaw moment
Wheel and inertia moments
Basic Physical Principles
Concept of Friction Circle
Radius of friction circle
Resultant force
Inter-relationships between forces
Total force within friction circle
Low lateral force (s)
Total force=Brake pressure
Components of ESP
Steering wheel angle sensor Yaw rate sensor Lateral acceleration sensor Wheel speed sensor Longitudinal acceleration sensor Roll rate sensor
What does ESP do?
It decides-1. What wheel to brake or accelerate and to
what extent,2. Whether engine torque is reduced and3. Whether the gearbox control unit is activated
on vehicles with automatic gearbox.
How does ESP work?Speed
sensors provide
continous data
Control units
calculate desired steering action
Lateral and Yaw
sensors send
information
Calculates actual
state of vehicle
If actual and
desired values don’t
match, it intervenes
Checks if intervention successful
If yes, ends intervention
If no, repeats intervention
cycle
SENSORS/COMPONENTSCode Sensor name Location Function
J104Control unit
Front right footwell
Processing, monitoring,
commanding
G85Steering angle
sensorBetween steering column and wheel
Transfers steering wheel angle to control
unit
G200Lateral
acceleration sensor
Below driver’s seat
Determines action of lateral
forces on stability
G202 Yaw rate sensor Below driver’s seat
Determines action of torque
G201Brake pressure
sensorConnected to
hydraulic pumpCalculates
wheel braking forces
---- Button for ESP Dashboard Switch ESPon/off
EFFECTIVENESS ESC reduces crashes by 35%- National Highway
and Traffic Safety Administration, USA Upto 10,000 fatal US crashes could be
avoided annually- US Institute for Highway Safety
Improved vehicle handling reduces skids and rollovers
Induces rider confidence
COST AND AVAILABILITY Available in Indian cars even under 10
lac rupees:
Ford Ecosport 1.5 Hyundai i20 Renault Duster Hyundai Verna Nissan Micra
FUTURE SCOPE
ESP to be mandated in Japan, Korea, Russia, and Turkey in the coming years
Developing of newer algorithms to tackle problems like trailer sway, in the effect of vehicle towing
Then, now, and future
India
CONCLUSION Life saving technology An aid to human, not a substitute to
human Safe driving habits are must
References “Bosch InnoWaves”, News and Information for Customers of Bosch Automotive Technology OE
Sales & Marketing | Issue 20 | May 2014 “Electronic Stability Programme”, Self-study Programme no. 204, 840.2810.23.20,
Volkswagen Technologies “Brief history of Electronic Stability System”,
http://www.safetyresearch.net/blog/articles/brief-history-electronic-stability-controls-and-their-applications
“Bosch predicts acceptance of ESP in Indian Vehicles” http://www.autocarpro.in/news-international/bosch-acceptance-esp-indian-vehicle-growing-percent-2021-6715
"Real world crash evaluation of vehicle stability control (VSC) technology", G. Bahouth.
"The Effectiveness of ESC (Electronic Stability Control) in Reducing Real Life Crashes
and Injuries", Anders Lie, Claes Tingvall, Maria Krafft, and Anders Kullgren, of the 19th Enhanced Safety of Vehicles Conference, 2005
The Greatest Advance in Safety Since Seatbelts, retrieved 2007-12-28 "Traction Control System for Improved Driving Safety", SAE Technical Papers
THANK YOU