Ilmanjousitus

Ilmanjousitus is the Finnish term for air suspension, a vehicle support system that uses compressed air cylinders, also called air springs, to maintain a constant ride height. The system replaces conventional metal leaf or coil springs and allows the vehicle to adjust its load-bearing characteristics by varying the air pressure inside the cylinders. This is achieved by a compressor, a reservoir, pressure valves, and a control unit that monitors vehicle speed, load, and suspension position.

The concept of air suspension dates back to the 1920s when the German automaker Panhard introduced pneumatic shock absorbers. In Finland, the first widespread use appeared in the 1970s with heavy trucks and buses, where a quieter, smoother ride was desirable. In the 1980s and 1990s, the technology spread to passenger cars and luxury vehicles. Finnish companies such as Toyo Tires and John Deere have adopted air swing systems for agricultural and construction machines.

Technical features of an Ilmanjousitus setup include adjustable ride height, load leveling, and the ability to change suspension characteristics for different terrains. The air springs consist of a diaphragm or bag that expands when air is pumped in, and contract when pressure is released. Sensors in the vehicle detect the load and feed data to a microcontroller, which modulates valves to keep the desired height.

Advantages of air suspension are lower maintenance cost, reduced noise, lower impact forces, and the ability to maintain level attitude under varying loads. Disadvantages include higher initial cost, potential for air leaks, and a greater number of electronic components that may require diagnostics. Overall, Ilmanjousitus provides improved ride quality and vehicle handling for many modern transportation applications.