Analyzing the design and energy efficiency of compressed air systems through simulation

For years, simulation-based analyses of air suspension systems have been carried out in the field of heavy machines, commercial vehicles, and buses and used for system design and energy analysis. Most of these systems are passive level-controlled systems that increase the ride comfort and functionality of the vehicles. A great example is a bus in urban traffic, which can lower the chassis on one side at bus stops to make it easier for passengers to get on and off the bus or make their stay more pleasant during the journey (thanks to the high-ride comfort of the air suspension). This also applies to trucks in long and short-haul operations and to operating heavy machines to create the most comfortable experience possible for the user.

In addition to the existing requirements for automotive safety and comfort, requirements will become even more stringent with the switch to autonomous driving for passenger cars. To optimize autonomous drive time for other activities, such as working or reading, while undisturbed and without physical discomfort (e.g., motion sickness), it is necessary to reduce the vehicle chassis accelerations in relation to external influences, like road bumps, or perceived accelerations as a result of starting and braking processes or cornering. This can only be achieved by an active suspension system.

In current luxury-class model vehicles and EVs, air suspension systems have been standard for some time and can be used in an active version to influence the isolation behavior:

• High comfort due to soft basic tuning
• Load changes are compensated by a level control system
• Additional comfort functions such as lowering the vehicle's body for entry or raising it for off-road driving and light trucks

These advantages of air spring systems are used as an initial point for further developments. With appropriate enhancements such as adapted components, additional valves, and adapted control strategies, ride comfort and safety can be increased. Which adaptations and extensions lead to the desired behavior can be determined by simulation.

However, these benefits come at a price: increased energy requirements and components and correspondingly increased weight.