Hubertus Gawinski, head of Research and Development at ContiTech, and his team are carrying out pioneering work in developing air springs with lightweight plastic pistons.
In nearly all industries from the automotive industry, railway engineering, aeronautics, machine and plant engineering, through to the construction industry and medical and energy technology, lightweight design is both a mega trend and a key technology. Material, weight, and, in turn, cost savings are becoming increasingly important for buses and trucks as well as construction and agricultural machinery, too. Lower emissions, lower consumption, reduced operating costs, an increasing pay load, and – last but not least – stricter CO2 emissions guidelines and exhaust gas standards such as Euro 6 are the driving forces behind innovation. For this reason, commercial vehicle manufacturers and suppliers are fighting over every last gram of weight, and, in turn, over every single liter of diesel that can be saved and every single gram of CO2 that is not emitted. All vehicle components have to play a role here.
In its capacity as a leading global supplier and development partner for air springs, ContiTech has for many years been a strong partner to renowned manufacturers. With the development of the plastic piston with a fully usable inner volume, the company is taking on a pioneering role. At the 2nd VDI Conference Plastics in Commercial Vehicles in Mannheim, Hubertus Gawinski highlighted the potential for reducing weight through the use of air springs with fiberglass-reinforced plastic roller pistons. The innovative design of the air springs also offers the best possible damping and ride comfort.
Lightweight plastic replaces steel and aluminum
Modern commercial vehicles and buses have to meet very strict requirements regarding transport efficiency. The challenge here is to increase the pay load while ensuring compliance with statutorily limited axle loads in order to increase the efficiency of goods transportation. Here, reduced weight not only means reduced fuel consumption and, in turn, reduced operating costs: "An important economic aspect is the opportunity to increase the load capacity.
Cross section of an air spring with plastic piston: the lightweight components from ContiTech reduce weight, consumption, and emissions, and improve vehicle dynamics, safety, and comfort.
With our weight-reduced air spring family, manufacturers can save 12 to 15 kg per axle. Given a service life of 400,000 kilometers, this means a 200 kg reduction in CO2 emissions," said Hubertus Gawinski from ContiTech. Compared with conventional steel pistons, the use of a special plastic can help to reduce weight by up to 75%.
Next level in comfort
Another important advantage of these lightweights with plastic pistons is that, just like with steel pistons, the inner volume can be used to the full in order to enhance comfort. With this optimization measure, ContiTech ensures the best possible ride comfort because the transmission of road undulations to the vehicle is reduced. Directional stability is increased. This not only increases safety thanks to improved vehicle dynamics and easier handling but also protects the driver's health. All other components are subjected to less stress as well, and goods that are sensitive to impacts are brought safely to their destination. Another favorable side-effect is the protection offered to the road surface.
Air spring systems with plastic pistons have been used for many years now, particularly in trailers. However, these conventional systems only use the internal volume for ride comfort. The associated pistons are generally completely closed. "With the correct raw material, the necessary analysis skills, and an intelligent product design, we can achieve the strength that allows us to produce an open plastic system with a useful piston volume," added Gawinski. "With our lightweight construction expertise, we are stealing a march on vehicle components previously made from steel or aluminum. We are therefore marking a new milestone. Heavy-duty plastics are the future, the next level in truck development."
Extremely robust in the long term
The air spring system originally developed by ContiTech for the Mercedes-Benz Actros has already proven its usefulness thousands of times. The company has now managed to persuade other manufacturers to opt for this innovation. "Our calculations also allowed us to reduced material usage, thereby leading to further savings in material costs during manufacture. We are currently working on the further development of this system. Designed even more smartly, systems with internal buffer stops will be able to absorb stronger forces. We also want to offer our air spring with plastic pistons with an integrated air damping function in Europe as well, as is already happening in series production in the U.S.A.," emphasizes Gawinski.
Trucks have a service life of around 24 years before being sent to a recycling company. During this time, they clock up an extremely high annual mileage, with their components frequently being exposed to extraordinarily high stress levels. Thanks to the use of plastic, no additional surface protection is necessary in order to safeguard the component's corrosion resistance. This protects the environment, and the durability of ContiTech's air spring system is guaranteed, even under adverse weather conditions.