Air Suspension System

ABSTRACT

           Air ride suspension carries the load on each axle with a pressurized air bag much like a high pressure balloon. Air ride suspension systems have been in common use for over forty years and have proven to provide the smoothest and most shock-free ride of any known vehicle suspension system. Modern air bags are constructed using the same methods as a tire by using high strength cords which are then encapsulated in rubber. These units are very durable in service and have a proven life of many years.

            In addition to providing extremely smooth ride quality, air ride suspension also provides other important features. First, the system automatically adjusts air pressure in the air bag so that the trailer always rides at the same height, whether lightly loaded or heavily loaded. This allows the suspension system to always provide the maximum usable wheel travel independent of trailer load. In addition, the higher air bag pressure associated with higher trailer loads, automatically provides a stiffer suspension which is exactly what is required for a smooth ride. The lower air bag pressure for lightly loaded conditions, automatically provides for a softer suspension, thus providing the same ride quality for all trailer loading conditions. Since each axle is independently supported by its own air bag, the air ride suspension is a truly, fully independent suspension system.

           The automatic control of the air bag pressure is accomplished by a solid state electronic control system specifically designed and packaged for vehicle use. This system continuously monitors the "ride height" of the trailer suspension and increases air pressure if the ride height is too low, by turning on an on-board air compressor. The air compressor stops automatically when the proper ride height is reached. If the ride height is too high, an automatic vent valve vents excess air pressure and stops venting when the proper ride height is reached. All required electrical power is provided by a 12 volt battery contained in the trailer equipment compartment.

 Introduction of  Suspension system

Suspension is the term given to the system of springs, shock absorbers and linkages that connects a vehicle to its wheels. Suspension systems serve a dual purpose — contributing to the car's road holding handling and braking for good active safety and driving pleasure, and keeping vehicle occupants comfortable and reasonably well isolated from road noise, bumps, and vibrations, etc. These goals are generally at odds, so the tuning of suspensions involves finding the right compromise. It is important for the suspension to keep the road wheel in contact with the road surface as much as possible, because all the forces acting on the vehicle do so through the contact patches of the tires. The suspension also protects the vehicle itself and any cargo or luggage from damage and wear. The design of front and rear suspension of a car may be different.

PROBLEM DEFINITION

2.1 General Problems without Suspension:

•        Unspring Weight

Having a large beam connecting the two front wheels results in a lot of mass. This extra mass really hinders the road holding capability of the suspension on rough road.

•        Wheel Movement

Because both wheels are tied together the force acting on each wheel are directed to the other wheel. Under the load this cause the wheels to‘Shimmy’ and decrease the stability of the vehicle in corners

•        Bad Bump Steer

Because a beam axle makes locating the steering correctly difficult , most solid axle suspensions suffer from an uncontrollable amount of bump steer . Again, hindering the  performance of the car.

•        Size

Simply put solid axle are huge and fitting them into a chassis requires an amount of space practically available.

•        Ride Quality

Due to the high mass of  the axle and the wheels being connected there is not much ride isolation between the springs and unsprung mass. This results in rough ride and even worse, compromised road holding capacity.

CONCLUSION

Air suspension is today mainly feature for luxury vehicle . It  offers a lot of feature for compact class. Cost or price level will be more attractive. Integration & smart design is key. The Air Suspension System has  ability to change the load carrying capacity simply by changing the air pressure.

From the whole discussion in air suspension system, I observe that the system is like a white blood cell .As white blood cell provides energy to our body to fight against diseases or viruses which try to destroy or try to decrease our life ,in the similar way air suspension system provides the energy to a vehicle to protect itself from damaging, increasing life of the vehicle ,increases the handing , increases comfort of passengers and many more.