Suspension System1. Mc Pherson Strut for all four
1.1 AboutThe MacPherson strut is a type of car suspension system
which uses the top of a telescopic damper as the upper steering
pivot.
The system was invented in 1955 and used on the first Ford
Consul. The MacPherson suspension is a technology for front and
rear suspension. It is an independent suspension type, including a
single suspension arm (spring and damper), an anti-roll bar and a
lower arm
1.2 Design
MacPherson For front
Use of MacPherson in Front MacPherson Section
MacPherson For Rear
Vehicle Using Macpherson strut
1.2.1Terminology
Camber angle angle between the wheel plane and the vertical
taken to be positive when the wheel leans outwards from the
vehicle
Swivel pin (kingpin) inclination angle between the swivel pin
axis and the vertical Swivel pin (kingpin) offset distance between
the centre of the tire contact patch and intersection of the swivel
pin axis and the ground plane Castor angleinclination of the swivel
pin axis projected into the foreaft plane through the wheel
centrepositive in the direction shown.provides a self-aligning
torque for non-driven wheels. Toe-in and Toe-outdifference between
the front and rear distances separating the centre plane of a pair
of wheels,quoted at static ride height toe-in is when the wheel
centre planes converge towards the front of the vehicle
1.2 Advantages
The struts are designed with more simplicity, and thus takes up
less space horizontally. They also display low un-sprung weight, an
advantage that reduces the overall weight of the vehicle as well as
increases the cars acceleration. Lower un-sprung weight also makes
your ride more comfortable Another major advantage of this system
is its ease of manufacturing as well as low cost of manufacture
compared to other stand-alone suspension systems Compact,
compliance close to completely independent suspension and hence
good for vehicle stability. reducing the unsprung weight (like with
MacPherson Struts) has a big effect on ride Comfort, and it greatly
reduces the work the suspension has to do, which ends up in some
parts lasting longer and staying in peak condition longer double
wishbones may perform better, but the MacPherson struts would prove
to be more affordable in the long run.
1.3 Disadvantage
Vibrations from the wheel are transmitted directly into the body
of the vehicle. That can result in excessive road noise and
vibration, which is mitigated somewhat by bushings and other
components and mechanisms. the strut in a MacPherson strut system
is an integral part of both the steering and suspension systems, a
failure can be catastrophic The MacPherson struts also have
problems working with wider wheels that have increased scrub
radius, where you would need extra effort to navigate your car in
this situation. Small camber change with vertical movement of the
suspension, which could mean the tires have less contact with the
road during cornering. This could reduce handling abilities of your
vehicle.
2 Double wishbone or double A2.1 AboutA double wishbone (or
upper and lower A-arm) suspension is an independent suspension
design using two (occasionally parallel) wishbone-shaped arms to
locate the wheel. Each wishbone or arm has two mounting points to
the chassis and one joint at the knuckle. The shock absorber and
coil spring mount to the wishbones to control vertical
movement.
2.2 Design
A cad model of double wishbone
Double Wishbone in Rear
For Front
Different Suspensions
Double wishbone in buggyA simpler design
Wishbone design
A cad model using front double wishbone2.3.1 Advantages
Independent suspension and hence best for vehicle stability and
relatively simpler to manufacture and assemble as compared to
McPherson strut DOUBLE WISHBONE suspension is the simplest, most
effective way to maintain a constant camber angle in an independent
suspension. increase of negative chamber as a result of the
vertical suspension movement of the upper and lower arms better
stability properties for the car as the tires on the outside
maintain more contact with the road surface The double suspension
system is much more rigid and stable than other suspension system
steering and wheel alignments are constant even when undergoing
high amounts of stress.2.3.2 Disadvantages Costly, needs more space
and high maintenance. Repair, modification and maintenance costs
and complexities for double wishbone suspension systems are
normally higher Due to the increased number of components within
the suspension set up it takes much longer to service and is
heavier than an equivalent MacPherson design More unsprung
Weight
3.Cost1. The cost of the suspension in both MacPherson and
wishbone would remain same2. The double wishbone require more parts
and bushing while the MacPherson require less Components3.