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Air Suspension Code
[attachment=16818]
Introduction
Over the past 20 years suspension design changes, more durable components and
operational needs have evolved to where the industry today has largely taken up air
suspension, often considered to be road friendly suspension .
Reasons for this large scale uptake in Australia vary, but include:
1. Various comparative testing by road agencies has shown air suspensions to be the most
road friendly, hence the now common reference to road friendly suspensions . Some
mechanical suspensions have now been tested and found to meet the road friendly
performance criteria.
2. Manufacturers have built a greater degree of durability, with longer warranties,
extending vehicle component life, giving improved resale values.
3. Reduced vibration and shock loading giving better cargo ride through superior load
springing and the lower natural frequencies of air suspension systems.
4. Improved driver comfort, and road holding, loaded or empty.
5. Improved braking, as a non-reactive system, no axle-hop, assisting the operation of load
proportioning valves in certain cases.
6. The biggest incentive in Australia to use air suspensions has been the prospect of higher
mass limits.
Code Purpose
This code recommends practices and procedures that will help the vehicle owner, maintenance staff
and drivers to better understand the operation and maintenance of air suspensions.
The Australian Road Transport Suppliers Association (ARTSA) membership includes not only major
heavy vehicle suppliers but many major component manufacturers and suppliers to the Australian
heavy vehicle market. ARTSA sees this code as a positive step to improving wider understanding
among all levels of road transport industry personnel.
This code has been prepared with input from various ARTSA members, the Australian Trucking
Association (ATA), and other contributors.
Suspension Certification
The Department of Transport and Regional Services, Vehicles Safety Standards Branch manage
a certification process that identifies Road Friendly Suspensions Performance and Component
Requirements .
These requirements apply to all new suspension systems put into service after January 2000, with
a Road-Friendly suspension classification as set out in performance standards developed by the
National Road Transport Commission. (See glossary.)
Road-Friendly Certificate Numbers (RFCN) are issued, identifying the original equipment supplier with
an RFCN, after the submitted suspension passes the required test. The supplier identifies the approved
suspension with a label or plate in accordance with that supplier s component traceability procedure.
Principles of an Air Suspension
The first air-spring patent was issued to John Lewis of New Haven Connecticut in 1847. The history
of air suspension shows the first early development on production passenger cars in 1914. Further
development progressed during the early 1950 s with the GM Greyhound buses and GM parlor car
passenger rail carriages. After early difficulties, air suspension has finally gained wide acceptance
on trucks and trailers.
A heavy vehicle suspension system s basic design function is to attach the axles to the frame of the
vehicle and to equalize or distribute vehicle weight in specific ratios between axles. Vehicle weight
distribution becomes extremely important during brake applications, cornering and whilst negotiating
uneven surfaces.
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[attachment=6676]
AUTOMATIC AIR SUSPENSION
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
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Air suspension system
The conventional metal springs faced some drawbacks which were air suspension system overcomes and so they are preferred and used in more these days. Let's see some of the plus points of this system.
1) The automatic control devices installed in the vehicle allows making optimum use of the variable space for deflection of wheel.
2) The height of the automobile remains steady and so the changes in the alignment of headlamp due to varying loads are restricted.
3) It helps to reduce the load while the vehicle in motion i.e. the dynamic loading as the spring rate variation between laden and unladen weight is much less.
4) It gives smooth and comfort ride of the vehicle.
Air springs are classified into two types:
1) Bellow type and
2) Piston type
Please refer to the sketch of air suspension system
The air springs shown are mounted on the front and rear axle. The atmospheric air first passes through the filter where the dirt is removed and passed on to the compressor. Air is compressed here and the pressure of air is raised from atmospheric to about 250 Mpa. This pressure is maintained by the accumulator tank. The safety relief valve is provided on the accumulator as a safety device and it opens when the pressure rises above 250 Mpa. This air then moves to lift control valve and through leveling valves to te air springs.
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[attachment=6725]
[attachment=6725]
AUTOMATIC AIR SUSPENSION SYSTEM
Submitted by
MANGESH M. MASNE
Guided by
PROF. S. R. NIRMAL
DEPARTMENT OF MECH ENGG , SSGMCE , SHEGAON
INTRODUCTION
The automatic air suspension system is an air-operated, microprocessor controlled suspension system. This system replaces the conventional coil spring suspension and provides automatic front and rear load leveling. The air bags, made of rubber and plastic, support the vehicle load at the front and rear wheels .
Sir William Brush is the father of suspension system in automobiles.
ROLE OF Air SUSPENSION SYSTEM
The main role of air suspension system are as follows:
It supports the weight of vehicle .
Provides smoother ride for the driver and passengers i.e. acts as cushion.
Protects your vehicle from damage and wear .
It also plays a critical role in maintaining self driving conditions.
It also keeps the wheels pressed firmly to the ground for traction .
It isolates the body from road shocks and vibrations which would otherwise be transferred to the passengers and load.
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[attachment=6725]
AUTOMATIC AIR SUSPENSION SYSTEM
Submitted by
MANGESH M. MASNE
Guided by
PROF. S. R. NIRMAL
DEPARTMENT OF MECH ENGG , SSGMCE , SHEGAON
INTRODUCTION
The automatic air suspension system is an air-operated, microprocessor controlled suspension system. This system replaces the conventional coil spring suspension and provides automatic front and rear load leveling. The air bags, made of rubber and plastic, support the vehicle load at the front and rear wheels .
Sir William Brush is the father of suspension system in automobiles.
ROLE OF Air SUSPENSION SYSTEM
The main role of air suspension system are as follows:
It supports the weight of vehicle .
Provides smoother ride for the driver and passengers i.e. acts as cushion.
Protects your vehicle from damage and wear .
It also plays a critical role in maintaining self driving conditions.
It also keeps the wheels pressed firmly to the ground for traction .
It isolates the body from road shocks and vibrations which would otherwise be transferred to the passengers and load.
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Air Suspension System
Welded joints in a welded structure are expected to possess certain service-related capabilities. Welded joints are generally required to carry loading of various types in which the weld is subjected to stress of either a simple or complex character. More over a finished weld is not always as good or as bad as it may appear to be on its surface. It is therefore necessary to find out how satisfactory or sound the weld is. For this purpose certain weld inspection and testing procedures have been discovered and standardized to estimate the expected performance of the welded structures.
The examination and test applied to welded joints range from relatively simple ones such as visual inspection of the surface of the weld which provides some information on the quality of the workmanship and presence or absence of surface defects to the more elaborate procedures carried out for the purpose of obtaining some knowledge of the behavior of the welded joint under operating conditions.
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i want full seminar report and power point presentation on air suspension.
