MAHLE develops new lead-free engine bearings for heavy-duty diesels; polymeric coatings with lead-free linings
MAHLE Engine Components has developed an innovative lead-free bearing system combining highly engineered polymeric coatings with robust lead-free bearing linings for heavy-duty truck engines. The new system delivers improved performance compared to existing bearing linings that include lead.
Our new bearing system provides a great combination of proven cast-bronze bearing technology with a polymer overlay that features high load capabilities, as well as seizure and wear resistance.—Dr. Joachim Wagenblast, head of Product Development for MAHLE Engine Components USA
Polymer technology is well established in the light- and medium-duty market for engines under 10 liters in displacement, according to James George, head of product technology at MAHLE. The need to adopt the technology for loaded bearings on heavy-duty applications in North America reflects changes in bearing operating conditions and a market need for alternative solutions, George said.
Improvements in wear resistance will help engine manufacturers cope with newly released low-viscosity engine oils which are required to help improve fuel economy, he noted.
MAHLE research shows that compared to lead-free bearings with electroplated coatings, MAHLE's polymer-coated bearings offer increased resistance to both wear and fatigue.
Customer testing of polymer-coated crankshaft main bearings and connecting rod bearings also has shown remarkably improved performance compared to more commonly used electroplated leaded bearings.
MAHLE’s polymeric coatings offer a variety of other benefits as well. Removing lead from the bearing improves corrosion resistance and allows for extended oil-drain intervals. Lead-free bearings also are environmentally safer and easier to dispose of.
Overall, industry testing indicates the new bearing system will offer significant owner-operator cost savings as well.
Comparative testing by a major commercial-vehicle engine builder, for example, showed polymer-coated bearings delivered distinctly better post-test wear results.
Production of the new bearing system began this summer at a MAHLE facility in Atlantic, Iowa.
The first heavy-duty diesel engines using MAHLE’s polymeric lead-free bearings will appear on vehicles being introduced during the second half of 2016. Product development programs for additional applications currently are underway with two major engine manufacturers.