Suspension System Fundamentals 6t4e1y

Suspension system fundamentals The suspension has several important functions. They are: 1) the weight of the frame, body, engine, transmission, drive train, and engers. Also called sprung weight. 2) Provide a smooth ride with minimal car body movement. 3) Allow rapid cornering without body roll. 4) Keep the tires firmly planted on the road surface for maximum control at all times. 5) Prevent excessive body squat during acceleration. 6) Prevent excessive body dive during deceleration. 7) Allow the wheels to turn from side to side for steering. 8) Work with the steering system to help keep the wheels in correct alignment.

Basic suspension components 1) Control arm-is a movable lever that fastens the steering knuckle to the vehicle frame or body. One end contains a ball t and the other contains a rubber bushing. 2) Steering knuckle-spindle or bearing for mounting wheel hub, bearings, and wheel assembly. 3) Ball t-swivel t that allows the control arm and knuckle to move up and down and from side to side. 4) Spring-s the weight of the car. Permits up and down suspension movement. 5) Shock absorber-keeps suspension from continuous bouncing after going over bumps. 6) Control arm bushings-sleeves that allow suspension movement of the control arms and dampen some road shock.

Suspension types Nonindependent-contains both the right and left wheels attached to the same, solid axle. When one wheel hits a bump it causes the other wheel to tilt up on an angle. This type does not usually have a smooth ride. Independent-contains separate suspension components for the right and left wheel. As one wheel hits a bump it will not affect the other wheels ride or alignment angle.

Suspension spring types Suspension springs must jounce (compress) and rebound (extend) with bumps and holes in the road surface. They the weight of the car while still allowing suspension travel.

Coil spring-is a length of spring steel wound into a spiral. It is the most common type of vehicle spring used on a modern suspension system.

Leaf spring-is made from flat spring steel, or fiberglass. Many leaves can be stacked to provide greater stiffness and ride height. Below is picture of the disadvantage of the leaf spring on a rear wheel drive car.

Air spring-is a two-ply rubber cylinder filled with air. Air pressure inside the cylinder allows the unit to have a spring action. The system will usually have an air pump with a ride height sensor to pump up or deflate the cylinder for a proper ride or height of the car. Torsion bar-is a long bar made of a spring steel rod. One end is attached to the frame and the other end is attached to the control arm. The up and down movement of the suspension twists the bar which will be resisted by the spring action.

Spring rate-refers to the stiffness or tension of a spring. The rate of a spring is determined by the weight needed to bend it. Sprung weight-refers to the weight of the parts that are ed by the springs and suspension system. Sprung weight should be kept high in proportion to unsprung weight. Unsprung weight-is the weight not ed by the suspension or spring system. It is the tires, wheels, wheel bearings, steering knuckles, or axle housings. The unsprung weight should be kept to a minimum when deg a car. Strut rod-is used to hold and prevent the control arm from swinging towards the front or back of the car.

Ball ts-are used to permit swiveling and tilting action in the control arm while going over bumps and turning.

Shock absorbers-limit spring oscillations to smooth out the vehicle’s ride. Shocks can be filled with oil, gas, or air. The most common being the oil filled shock. The shock works by resisting the oil movement through a valve inside the body of the shock. The valve is connected to a rod that is attached to the car frame and the body of the shock is attached to the suspension system. Shock compression-occurs when the vehicles tire is forced up when hitting a bump. Shock extension-occurs when the car returns to normal height after hitting a bump.

Gas charged shocks-use a low-pressure gas to help keep the oil in the shock from foaming. The gas used is usually hydrogen and is enclosed in a separate chamber from the main oil. The hydrogen is used to maintain a constant dampening rate at all times.