What is a Cylinder Air Suspension?(A Brief Overview)

In this brief article, we will discuss the types of Cylinder Air suspension setups and their advantages and disadvantages.

What is a Cylinder Air Suspension?

A Cylinder air suspension is the type of air suspension that uses a Piston and cylinder arrangement to provide stiffness as well as damping to the wheels.

What types of Cylinder air suspension ?

The types of cylinder air suspension are:

• Cylinder actuator air suspension
• Air Cylinder Wheel suspension

Cylinder Actuator Air Suspension

The Cylinder Actuator type of air suspension is very similar to a conventional pneumatic suspension. It is a powered suspension that requires an air compressor to run and pressurize air within an air circuit. The air suspension runs on either an electronic control system (ECU) or a simple electrical solenoid system.

The main element of the Cylinder actuator suspension is the actuator cylinder, which is the equivalent of an Air bag or a regular coil spring. The Cylinder actuator is basically a Piston (actuator) and Cylinder arrangement, like an air bag suspension, where the air is compressed between the cylinder and Piston seal. Air, being compressible, will act as the spring element.

What are the advantages of the Cylinder Actuator Air Suspension?

The benefits of Cylinder Actuator Air Suspension are as follows:

Reduced Packaging Space

• The airbag type of suspension tends to expand whenever the suspension goes into bump
• The Cylinder actuator occupies a fixed space equal to the diameter of the actuator

Damping capability

• The Actuator cylinder can doubles as a damper as well as a spring
• By using a Slowdown Valves, the cylinder actuator can be made to function as a shock absorber. The valve is adjustable and therefore can be tuned for improving the ride quality.

What are the disadvantages of the Cylinder Actuator Air Suspension?

The disadvantages of the Cylinder Actuator sir suspension are:

• Because of the cylinders not having any expandability, there is a limited compression of air as compared to the air bag. This results in a very harsh ride quality.
• The piston and cylinders work only due to the sealing between the piston and cylinder. Whenever the suspension moves vertically, there is wear of the sealing between the piston and cylinder. This causes premature failures, as compared to an air bag suspension.

Air Cylinder Wheels

• An Air cylinder wheel is a relatively new type of suspension wherein the wheel itself acts as the Tire.
• The Air Cylinder wheel is suited more to Off-Road Mining Dump trucks like the big 400 ton+ capacity Caterpillar 797.
• The Air cylinder wheel suspension is a combination of an inner steel hub and an outer steel drum which are tangentially connected by twelve Gas-filled (Nitrogen) air cylinders and six hydraulic dampers. 
• The suspension action happens when the inner hub pushes down against the outer hub. The gas Struts get compressed, mimicking the softness of a tire and spring.
• On the outer periphery of the outer drum, steel or polyurethane treads are fitted, which can individually be bolted-on and replaced as and when necessary.

Advantages of the Air Cylinder Wheel suspension

• In the high tonnage Dump trucks, the normal pneumatic tyres are always at a disadvantage due to harsh conditions. Tire life is low and tires need to be replaced every few weeks. The Air Cylinder wheel provides drastic improvement in service life since only the outer treads need to be replaced. The treads are of harder durable material and hence provide a longer service interval as compared to a conventional tire.  As a result the Air cylinder wheel drastically reduces downtime due to tire replacement.
• The ride quality is drastically improved due to the gas struts and dampers replacing the tire’s softness. The ride quality is more predictable and controlled as compared to just having a tire.
• Tires disposal is environmentally damaging since they have to be disposed of in landfills. Therefore, the elimination of tires is a step towards a better environment.

Disadvantages of the Air Cylinder Wheels

• The Air cylinder wheel can only be used in an off-road mining truck where there is no concern about the outer diameter of the tire and ride heights are always high.
• In a normal road vehicle, packaging of the tire outer diameter would be an issue when trying to fit in 12 gas shocks and 6 dampers.

Conclusion

In this brief article, we have discussed the types of Cylinder Air suspension setups and their advantages and disadvantages.

In case of any questions or queries, please feel free to ask.