Federal-Mogul (www.federalmogul.com) Powertrain’s facility in Burscherd, Germany, has developed a new process for ranking the corrosion resistance of cylinder liner materials; this will enable it to supply components that are even more durable.

By allowing direct comparison of different materials and coating processes, the new test methodology allows material development to be specifically targeted at applications involving poor-quality fuel.

Chief technology officer Gian Maria Olivetti said: “Higher rates of exhaust gas recirculation — EGR — and the use of high-sulphur diesel fuels present significant challenges for the wear of ferrous cylinder bore surfaces.

“Advanced thermally sprayed liner solutions — like our Sprayfit thin-walled liner — could combine effective heat dissipation with the benefit of a wide range of wear resistant surfaces.

“However, it remains necessary to evaluate the performance of alternative material choices in a reliable way, and we now have a proven process to achieve this.”

Prior to the work by Federal-Mogul Powertrain, there was no recognised procedure for comparing the likely corrosion resistance of different materials during engine operation. The complex relationship between mechanical wear and corrosion means that each material must be evaluated independently in order to identify the most resistant.

Mechanical wear removes corrosion products to expose an unprotected surface, promoting further corrosion. The corroded surface has inferior wear resistance, which further accelerates wear in a continuous cycle.

Federal-Mogul Powertrain has accurately reproduced the corrosive solutions of combustion products formed inside an engine; moreover, the test solution can be controlled to reproduce the properties of a typical sulphur condensate or EGR condensate.

Test results showed that the most aggressive corrosion rates occurred through exposure to a sulphur condensate, and its effect on various materials was compared using a conventionally manufactured grade of cast iron as a reference.

Corrosion resistance was found to be improved with higher chromium content, but it deteriorated as the oxide content (iron oxides, chromium oxides) of the material increased.