four wheel steering configurations with the types of four wheel steering. It also goes through zero turning radius, crab steering, low speed steering and high speed steering.
3. INTRODUCTION
Four wheel steering is a system employed by vehicles
that allows the rear wheels to turn for maneuvering,
rather than just follow the front wheels.
It reduces the turning radius by 20% as well as the space
required for turning. It also enables to change road lane
while driving even at high speed.
At lower speeds, turning the rear wheels in the opposite
direction to the front wheels results in a smaller turning
radius and faster cornering responses. At high speeds,
turning all four wheels in concert improves high-speed
stability.
7. CONTROLLING OF REAR WHEELS
At slow speeds, the rear
wheels are turned in the
opposite direction of the front
wheels. This can lessen the
turning radius by
approximately 20%.
LOW SPEEDS(0-40 km/h)
8. CONTROLLING OF REAR WHEELS
At faster speeds on the
highway, the rear wheels
are turned in the same
direction as the front
wheels. This improves
lane changing
maneuverability and is
particularly beneficial
for vehicles towing a
trailer. HIGHER SPEEDS
(GREATER THAN 80 km/h)
12. MECHANICAL 4WS
• The mechanical 4WS
uses two separate
steering gears to
control the front and
rear wheels.
13. HYDRAULIC 4WS
The hydraulic 4WS
uses a two-way
hydraulic cylinder to
turn both the
wheels in the same
direction.
14. ELECTROHYDRAULIC 4WS
The electro/hydraulic
4WS combine
computer electronic
controls with
hydraulics to make the
system sensitive to
both steering angle
and road speeds
15. ZERO TURNING RADIUS
Zero turning radius
Require no space for
turning
On-spot Turning
16.
17. MODERN CARS WITH ACTIVE FOUR WHEEL
STEERING: -
•Acura RLX (P-AWS)
•BMW 850CSi (only Euro spec models)
•BMW 7-Series (2009 onward, part of sport package)
•BMW 5-series (2011 onwards, Integral Active Steering
option)
•Toyota Camry / Vista JDM 1988–1999 (Optional)
•Toyota Carina ED / Toyota Corona EXiV (world's first
dual-mode switchable 2WS to 4WS)
•Toyota Celica (option on 5th and 6th generation, 1990–
1993 ST183 and 1994–1997 ST203) (Dual-mode, high and
low speed)
•Toyota Soarer (UZZ32)
18. CONCLUSION
Requires less steering input for corrections.
Entire vehicle moves in one direction.
Greater Stability in maneuvers.
Turn in crab like manner rather than curve.
Reduces effecting turning radius.
4WS is complex and expensive.
19. REFERENCES
Suspension and Steering Systems, Design of modern
terrain vehicles
By- Shpetim lajqi
Stanislav Pehan
Automotive Mechanics
BY- Crouse and Anglin