this is for mech and about automotive Four wheel steering system

1. DEVELOPMENT OF
AUTOMOBILE TECHNOLOGY

2. Topics Covered
The History of the Automobile
Introduction
Why Four-wheel Steering (4WS) System?
Types
Mechanical
Hydraulic
Electro-hydraulic
Actual 4WS
Fail-safe measures
Advantages
Application

3. Nicolas-Joseph
Nicolas-Joseph Cugnot demonstrated his fardier à
vapeur ("steam dray"), an experimental steam-driven
artillery tractor, in 1770 and 1771.

4. 19th century
 Among
other efforts, in 1815, a
professor at Prague Polytechnic, Josef
Bozek, built an oil-fired steam car,
Walter Hancock, builder and operator of
London steam buses, in 1838 built a
four-seat steam phaeton.

5. First automobile in Japan in 1898, a Panhard.
Published in "La France Automobile" in 1898.

6. Internal combustion engines
In 1806, the
first cars
powered by an
internal
combustion
engine
running on
fuel gas
appeared,
Benz PatentMotorwagen,

7. FOUR-WHEEL STEERING
SYSTEM

8. INTRODUCTION
 What
is 4WS?
 How does it work?

9. Why Four-wheel
Steering (4WS) System?

10. Types
Mechanical
Hydraulic
Electro-Hydraulic

11. Mechanical 4WS System
Inside a rear-steering gear box is a simple planetary gear setup

12. Hydraulic 4WS System
Simple Hydraulic 4WS System

13. Electro-hydraulic 4WS System
An Electronically & Hydraulically controlled 4WS System using a Stepper motor &
Control yoke

14. Actual 4WS
 Rack
and pinion front steering, hydraulically
controlled
 Rear-steering shaft
 Vehicle speed sensors
 Steering-phase control unit
 Centering lock spring
 Solenoid valve

15. Fail-safe measures
 Hydraulic failure
 Electrical failure
 Positioning of the wheels

16. Advantages of 4WS

Speed can be varied
Slow

Medium
Improved maneuverability
Fast

17. • Better handling
in tight corners
• Better parking
• Stability is
increased
4WS
2WS

18. Application

19. Conclusion

Advantageous to 2WS

Complex and expensive

Cost may drop as the system becomes
common

20. THANK YOU