What Is an Air Suspension System?
An air suspension system is a style of vehicle suspension that's powered by an electric pump or compressor that pumps air into flexible bellows that are typically made out of a textile-reinforced type of rubber. Additionally, Pro Car Mechanics describes air suspension as a replacement to the leaf suspension or coil spring system with airbags composed of polyurethane and rubber. A compressor inflates the bags to a certain pressure in order to behave like springs. Air suspension also differs from hydropneumatic suspension because it uses pressurized air instead of pressurized liquid.
What's the Purpose of an Air Suspension System?
In most cases, air suspension is used to achieve a smooth and constant driving quality, but in some instances, sports suspensions feature an air suspension system too. Similarly, air suspension replaces a conventional steel spring suspension in heavier vehicle applications, like trucks, tractor-trailers, passenger buses, and even passenger trains. Air suspension has also become popular in low-riding trucks like this gorgeous 1982 Dodge D200 Camper Special.
What Is Electronically Controlled Air Suspension?
According to the company now known as Dunlop Systems and Components, at the start of the 1990s, Dunlop developed and installed the Electronic Controlled Air Suspension (ECAS) system on the 1993 Range Rover Classic and again on the Range Rover P38A. The United Kingdom-based company developed the ECAS to include several key features:
Vulcanized, heavy-duty rubber air springs at each of the vehicle's wheels
An air compressor in the vehicle's trunk or under the hood of the vehicle
A storage tank for compressed air, which allows you to store air at around an average of 150 PSI
Valve blocks which direct air to the four springs from the storage reservoir through a set of solenoids, valves, and o-rings
ECAS computer that communicates between the vehicle's main computer to calculate where to direct air pressure
Air pipes connecting from the storage tank to the air springs that channel the flow of air throughout the rear air suspensions system
A desiccant-filled drier canister to keep the internal recesses of the system dry
The electronically controlled air suspension also features height sensors that are based on sensing resistance in contact with the terrain on all four of the vehicle's corners to provide height reference for all corners. Additionally, further advancements are beginning to feature some Electronic Control Units (ECUs) that are able to fit under the vehicle's floorboard, making air suspension more widely featured in everyday driving.
The Benefits and Drawbacks of Air Suspension Systems
According to Future Marketing Insights, the total value of the air suspension market at the end of 2017 was around $4.3 million. So whether it's a manual or electronic air suspension system, the benefits can greatly improve the ride of the vehicle. Take a look of some of the benefits of front air suspenions:
More driver comfort due to the reduction in noise, harshness, and vibration on the road that can cause driver discomfort and fatigue
Less wear and tear on the suspension system due to reduced harshness and vibration of heavy-duty driving
Trailers last longer with air suspension because the system components don't take on as much vibration
Air suspension reduces the tendency of short wheelbase trucks to bounce over rougher roads and terrain when the vehicle is empty
Air suspension improves the ride height based on the load weight and a vehicle's speed
Higher corner speeds due to air suspension being better suited to the surface of the road
Air suspension increases the transport capabilities of trucks and trailers by providing a better grip that levels the entire suspension. An air suspension system can also be adjusted for feel, so drivers can choose between a softer feel for highway cruising or a harder ride for improved handling on more demanding roads.
In the case of hauling heavy loads, air suspension offers more consistency and keeps all wheels even. The air suspension system keeps trucks level from side to side, especially in cases where cargo is difficult to level. This results in reduced body roll when turning corners and curves.
Even with the benefits of an air suspension system, Driving Tests New Zealand suggests several drawbacks. Some of these disadvantages that so and so reports include:
The initial costs of purchasing and installing an air suspension system — air suspension can also sometimes reach three times the cost in repairs as a leaf suspension system over 10 years' time
Fuel overheads for running air compressor for occasionally pumping air to the correct pressure
Fuel efficiency can suffer from the heavier weight of air suspension over the weight of leaf suspension
An air suspension system's vulnerability to air leaks can result in malfunctions
Some of the drawbacks of air suspension systems are because of some of the mechanical issues they can be vulnerable to. Several of the common issues with air suspension systems that can require repair include:
Rust or moisture damage from the inside that can lead to the air struts or bags to malfunction
Failure of the air suspension tubing connecting the air struts or bags to the air system
Air fitting failure resulting from initial fitting or infrequent use
Compressor burn out due to air leaks in the springs or air struts from the compressor constantly engaging to maintain the proper air pressure
Even with these common mechanical problems, the benefits can far outweigh the drawbacks.