Ford Motor Co. is using a plasma coating technology to remanufacture old engines, in the process delivering what it says is a 50% reduction in CO2 emissions compared with producing a new engine.

“We have taken a process that was originally developed to enhance performance models....and used it to remanufacture engines that might otherwise be scrapped," says Juergen Wesemann, manager of vehicle technologies and materials at Ford Research and Advanced Engineering.

Plasma transferred wire arc (PTWA) coating technology applies a wear-resistant coating to the cylinder bore surface inside the worn-out engine block. This helps restore it to its original factory condition.

In PTWA, a single conductive wire, used as "feedstock" for the system, is melted by a supersonic plasma jet, atomized and propelled onto the substrate. Forced gas transports the stream of molten droplets onto the bore wall, which flatten and solidify upon contact to create a wear-resistant coating.

PTWA may deliver a 50% reduction in CO2 emissions compared with manufacturing a new engine. Image credit: Ford.PTWA may deliver a 50% reduction in CO2 emissions compared with manufacturing a new engine. Image credit: Ford.Thermal spray coatings have been used for years,and are popular in the aerospace industry for increasing the durability and performance of aircraft turbine engines. Ford researchers began collaborating with suppliers in the 1990s to transfer this technology to a low-cost, high-volume application suitable for the auto industry.

One of the challenges was to create a coating applicator, because commonly used thermal spray devices were not capable of coating cylinder bores of automotive engine blocks. Ford's PTWA spray torch technology was an enabler in making this high-volume coating process more reliable for automotive applications, while offering economies of scale for low-cost coating.

Ford began using the technology in 2010 on the GT500 Shelby Mustang 5.4-L V8 to replace the steel liners typically required of an aluminum block engine with a low-friction, wear-resistant thermal spray coating. Ford says the plasma-sprayed coating offered several advantages, including engine weight reductions, reduced friction between the piston rings and cylinder bore, improved fuel economy and improved engine performance due to better heat management.

Now the technology is being applied to worn-out engines. “Traditional engine remanufacturing techniques can be prohibitively expensive and energy intensive, requiring iron-cast parts and intricate machining processes," says Mark Silk, supervisor of powertrain products at Ford Customer Services Division Europe. "The PTWA coating technology removes the need for additional heavy parts and the processed engine block has a new life as the base of a replacement engine.”

To contact the author of this article, email GlobalSpeceditors@globalspec.com