Razor-thin yet pivotal

The turbocharger coating for low-emission passenger vehicle and truck engines is a coating solution developed specifically for the automotive market. More precisely, the coating of the compressor wheel in diesel turbochargers must be protected against corrosion and wear.

The challenge

The diesel engine is an important player when it comes to meeting consumption targets for reduction of CO2 emissions. Compliance with future legal emission stages for nitrogen oxide and particles, however, will require further development of the diesel engine. Solutions must be found that can be implemented reliably and effectively in series production at an affordable cost. The most promising method is low-pressure exhaust gas recirculation, in which the exhaust gas is diverted after the particulate filter and, in contrast to the high-pressure system, reintroduced to the combustion chamber upstream from the turbocharger’s compressor. Driven by the exhaust gas turbine wheel, the compressor wheel is a critical component that compresses the air in the turbocharger. It is exposed to particle and droplet impact as well as different temperatures and acids that attack the surface of the aluminum.

The solution

The Miba Coating Group has focused specifically on this area and on developing a suitable series solution that meets the automotive industry’s stringent requirements. The task was managed in close cooperation with turbocharger manufacturers. In order to protect the sensitive component, we coat the compressor wheel with a special electroless nickel plating. The coating has the ideal characteristics to protect the component against droplet and particle impact as well as corrosion. In order to keep the cost as low as possible while upholding the standard of optimal performance and quality, another focus was on industrialization. The Miba Coating Group offers a turbocharger coating ready for series production.