How does air suspension work?

Without a suspension system, driving would quickly become unbearable, and bumps could even leave physical scars. Typically, the load is supported by a system of coil springs or steel or composite leaf springs, but there is another, more discreet type of suspension: air suspension.

Air suspension is height-adjustable and replaces the springs of conventional suspension systems with air cushions to better absorb shocks. Available on luxury or utility vehicles (usually only in the rear), air suspension makes your suspension active. Let's take a look at how this type of suspension works, as well as its pros and cons.

What is air suspension?

Air suspension first appeared in the 1920s and has been used in cars since the late 1950s. It's one of several types of suspension you'll find on a car, but it can also be found on other types of vehicles: trucks, recreational vehicles, buses, vans, etc.

In vehicles equipped with integral air suspension, the traditional suspension is replaced with integral air suspension to smooth out bumps and irregularities in the road for greater comfort.

There are two kinds of air suspension:

• Integral air suspension;
• Air Reinforcement.

Air suspension is a suspension system powered by an electric pump or compressor that draws air through flexible bellows, usually made of a type of textile-reinforced rubber. Air suspension replaces leaf or coil spring systems with airbags made of polyurethane and rubber.

How does air suspension work?

An air suspension system consists of the following components:

• An electric compressor;
• A solenoid control valve;
• An exhaust solenoid valve;
• Air springs;
• Pneumatic lines;
• Height sensors;
• A computer.

To visualize how automatic suspension works, imagine bags that are inflated to a certain pressure by a compressor so that they act like springs. The goal is to automatically maintain a constant body height regardless of the load being transported.

The ECU controls the whole system. It receives an electrical signal from the height sensors based on the chassis height. It can then use solenoid valves to modulate the vehicle's ride height. The compressor delivers compressed air to the springs. The compressed air reaches the springs through pneumatic lines.

In general, air suspension can be operated either manually or automatically. In the first case, a manual control allows the driver to adjust the height of the suspension, sometimes on both sides.

In the second case, the ECU controls and adjusts the suspension height by controlling the air compressor and solenoid valves using information received from the height sensors.

What vehicles have air suspension?

Air suspension systems can be found on buses, trucks, and recreational vehicles. But this type of suspension is also suitable for vehicles that are driven over rough terrain, such as 4x4s.

In recent years, air suspension has become increasingly popular. Today it can be found on more and more passenger cars. You'll find air suspension on cars from the following manufacturers:

• Mercedes (especially the C class);
• Rolls Royce;
• Tesla;
• Ford;
• Lincoln (Continental and Mark VIII, for example);
• Audi;
• Lexus;
• Cadillac;
• Volkswagen;

Advantages of Air Suspension

• Comfort is the most obvious. Vehicles with air suspension are often described as "gliding" over the road. This compensates for potholes, uneven surfaces and speed bumps in the road.
• The reduction in noise and vibration also means less wear and tear on the suspension system and vehicle components, especially when driving hard.
• Air suspension is often adjustable. This means drivers can adjust the suspension for a softer ride on rough roads or a firmer ride for better handling.
• Off-road capabilities are also improved. For example, many SUVs use air suspension to increase ground clearance and improve approach, breakover and departure angles. Raising the suspension also means the vehicle is less likely to get stuck and suffer underbody damage.
• Using air suspension also saves fuel. For example, with a lower ride height, you benefit from better aerodynamics and can reduce wind resistance.
• Loading flexibility. The height of the vehicle can be adjusted to match the load, which is particularly beneficial for trucks and trailers, as they have a greater payload capacity due to the improved grip that levels the entire suspension system.

Disadvantages of Air Suspension

The initial cost of an air suspension system is higher than that of a traditional spring suspension system. As a result, only the highest-end luxury cars come standard with air suspension, otherwise, it's an option that comes at a significant additional cost.

The cost of maintenance. Despite their advantages, air suspension systems sometimes need to be repaired, otherwise, the car may lean to one side while driving. It is always possible to replace the air spring system with a cheaper traditional steel spring, but this would mean giving up the benefits of air suspension.