This project report summarizes a student group's research on hydraulic steering systems. The group members are Tariq aziz, Azeem waqar, and Saud zaman. The report provides an overview of how hydraulic steering systems work, including the key components like the reservoir, pump, relief valve, control valve, and power cylinder. It also discusses the principles of how pressure differences in the hydraulic fluid allow for steering assistance as well as the advantages of hydraulic power steering over mechanical systems.

1. Project report
Topic: Hydraulic steering system.
Group members.
 Tariq aziz # 123
 Azeem waqar # 116
 Saud zaman # 152 .

2. ‘‘Hydraulic steering system’’
Introduction.
In automobiles, a power steering (also known as power assisted
steering (PAS) or steering assist system)helps drivers steer by
augmenting steering effort of the steering wheel. Hydraulic or electric
actuators add controlled energy to the steering mechanism, so the
driver needs to provide only modest effort regardless of conditions
Representative power steering systems for cars augment steering
effort via an actuator, a hydraulic cylinder, which is part of a servo
system. These systems have a direct mechanical connection between
the steering wheel and the linkage that steers the wheels. This means
that power-steering system failure (to augment effort) still permits
the vehicle to be steered using manual effort alone.
Other power steering systems (such as those in the largest off-road
construction vehicles) have no direct mechanical connection to the
steering linkage; they require power. Systems of this kind, with no
mechanical connection, are sometimes called "drive by wire" or "steer
by wire", by analogy with aviation's "fly-by-wire". In this context,
"wire" refers to electrical cables that carry power and data, not thin-
wire-rope mechanical control cables.
In other power steering systems, electric motors provide the assistance
instead of hydraulic systems. As with hydraulic types, power to the
actuator (motor, in this case) is controlled by the rest of the power-
steering system.
Some construction vehicles have a two-part frame with a rugged
hinge in the middle; this hinge allows the front and rear axles to
become non-parallel to steer the vehicle. Opposing hydraulic cylinders
move the halves of the frame relative to each other to steer.

3. History
The first power steering system on an automobile was apparentlyinstalledin
1876 by a man with the surname of Fitts. Little else is known about him. The
next power steering system was put on a Columbia5-ton truck in 1903.[1]
Robert E. Twyford, a resident of Pittsburgh, Pennsylvania, USA, includeda
mechanical power steering mechanismas part of his patent (U.S. Patent
646,477) issuedon April 3, 1900 for the first four wheel drive system.
Components.
COMPONENTS OF HYDRAULIC SYSTEM
• The Hydraulic steering contains the following parts
Reservoir
Pump
Relief ValueControl Value
Power Cylinder
Components and its Functions.
• Reservoir=It supplies the fluid.

4. • Pump=Driven by the Engine through belt It transfer the fluid
from reservoir to relief value and than to the control value under
pressure.
• Relief Value=It provides an escape to the fluid back to the
reservoir
• Control Value=It directs the fluid to the Power Cylinder. It is
also called heart of hydraulic system.
• Power cylinder=It converts Hydraulic System into mechanical
force, which in turn activates Pitman Arm Shaft and lever.
PRINCIPAL OF WORKING
• The Hydraulic Steering works on the principal of
pressure differences.
• The difference in pressure affects the position of
piston in power supply which in turn affects pitman
arm shaft and lever.
Power Cylinder

5. Mechanism.
Most power steering systems work by using a hydraulic system to
steer the vehicle's wheels.[citation needed] The hydraulic pressure typically
comes from a gerotor or rotary vane pump driven by the vehicle's
engine. A double-acting hydraulic cylinder applies a force to the
steering gear, which in turn steers the road wheels. The steering wheel
operates valves to control flow to the cylinder. The more torque the
driver applies to the steering wheel and column, the more fluid the
valves allow through to the cylinder, and so the more force is applied to
steer the wheels.
Control system.
One design for measuring the torque applied to the steering wheel has
a torque sensor – a torsion bar at the lower end of the steering column.
As the steering wheel rotates, so does the steering column, as well as
the upper end of the torsion bar. Since the torsion bar is relatively thin
and flexible, and the bottom end usually resists being rotated, the bar
will twist by an amount proportional to the applied torque. The
difference in position between the opposite ends of the torsion bar
controls a valve. The valve allows fluid to flow to the cylinder which
provides steering assistance; the greater the "twist" of the torsion bar,
the greater the force.
Since the hydraulic pumps are positive-displacement type, the flow
rate they deliver is directly proportional to the speed of the engine.
This means that at high engine speeds the steering would naturally
operate faster than at low engine speeds. Because this would be
undesirable, a restricting orifice and flow-control valve direct some of
the pump's output back to the hydraulic reservoir at high engine

6. speeds. A pressure relief valve prevents a dangerous build-up of
pressure when the hydraulic cylinder's piston reaches the end of its
stroke.
Some modern systems also include an electronic control valve to
reduce the hydraulic supply pressure as the vehicle's speed increases;
this is variable-assist power steering.
The steering booster is arranged so that should the booster fail, the
steering will continue to work (although the wheel will feel heavier).
Loss of power steering can significantly affect the handling of a
vehicle. Each vehicle owner's manual gives instructions for inspection
of fluid levels and regular maintenance of the power steering system.
The working liquid, also called "hydraulic fluid" or "oil", is the
medium by which pressure is transmitted. Common working liquids
are based on mineral oil.
Advantages.
 Road feel.
Power steering provides some feedback of forces acting on the
front wheels to give an ongoing sense of how the wheels are
interacting with the road; this is typically called "road feel".
• HPS has no steering wheel torques as compared to mechanical
system.
• In HPS no freezing of steering is caused by dried up grease or
corrosion in steering tube of vehicle .
• It can be used in big vehicle where electronic system fails.
• It absorbs major part of road shock as compared to mechanical
system.