INTRODUCING CHANGE
For fifteen years, Federal-Mogul, headquartered in Southfield, Michigan, has partnered with MTI for prototyping capabilities, weld development, new piston design and evaluation.
“Over the years MTI has worked with Federal-Mogul on a variety of projects including jumping in to handle overflow, as well as Pre & Post production inspections and processing of parts. At an average, we can produce up to 25,000 pistons a month,” explained Dan Adams, Chief Technology Officer at MTI.
In 1993, when MTI first started working with Federal-Mogul, global requirements on tail pipe emissions were forcing engine manufacturers to reduce gaseous and particulate emissions. In order to counter the reduction in fuel economy due to combustion changes in the engine mandated by the emissions regulations, the engine companies increased the pressure in cylinders to regain lost efficiencies.
These changes exposed the vulnerability of the aluminum piston, which dominated the truck and industrial diesel engine industry up until the 1990s. By increasing cylinder pressures and higher heat loads, aluminum pistons became a constraint due to low strength and durability, and low temperature resistance. A solution needed to be identified.
THE INITIAL IDEA
It was evident to a Brazilian company, Metal Leve, that a steel piston was necessary to correct the weaknesses.
“Metal Leve, acquired by Federal-Mogul in 1998 came up with the idea to weld these two steel forgings together to create a large cooling gallery and creating a very strong piston architecture,” explained Keri Westbrooke, Director of Engineering and Technology at Federal-Mogul Powertrain.
As luck would have it, Metal Leve had a technical center in Ann Arbor, Michigan, near MTI’s headquarters in Indiana. As Federal-Mogul started to develop their idea, they were pointed in the direction of MTI as a welding option.
DIVING INTO THE CHALLENGE
With their process for the steel piston, MTI was making two welds simultaneously. The result addressed the problems of the original aluminum piston. The Monosteel® piston resulted in a strong box section gallery to withstand the firing pressures, a large enclosed gallery to contain the cooling oil, a full steel skirt, and a improved bearing surfaces to transmit the bearing loads. “The hollow gallery allows them to circulate the oil through the piston during the operation, allowing them to decrease piston temperatures in operation, and significantly increasing durability,” said Adams.
“We had an interesting challenge of developing the compromise between the inner and outer weld surfaces. Normally, it’s just a factor of rotational speed, inertia energy and pressure to get the right temperature and the right bond parameters on a single surface. But now we have two surfaces – an inner and outer,” said Westbrooke.
In 2003 the first Monosteel piston was first used for high volume production. By 2010, emissions legislation from the United States government required engine manufacturers to have a much higher power density, and hotter and higher pressure engine solutions. The legislation called for an even greater challenge for the cylinder environment of the piston. Federal-Mogul’s Monosteel piston was the strongest and coolest piston to step up to that challenge.
A SUCCESSFUL SOLUTION
The piston was primarily used for Class 8, heavy-duty diesel engine trucks, but is now the preferred choice of the major engine manufacturers for industrial engines, and smaller bore automotive diesels.
The Monosteel piston has become a market leader in the industry.
In 2006, the Monosteel piston received the PACE Award from Automotive News. The award recognized Federal-Mogul’s innovation, technological advancement, and business performance among automotive suppliers.
“Sometimes the solution is there waiting for a big enough problem to come along,” said Westbrooke. “We are now producing millions of these pistons a year. We have 8 MTI welders around the world. It’s been a big investment for us. But we now have manufacturing lines in Mexico, Poland, Turkey and we’re talking about putting these friction welders into other parts of the globe as well.”
