Last year when we talked with MAHLE’s Sales & Marketing Manager, Trey McFarland, he explained that “direct injection was where the future was going to be and piston technology was going to have to take a large step up.” At this year’s SEMA tradeshow in Las Vegas, we saw MAHLE taking that step with the introduction of their new Monotherm Duramax pistons.

Development and production of pistons has always been the core of MAHLE’s line of products, and the company has stayed true to their primary  focus of developing pistons to stay with or ahead of changing engine technology.

“We do a lot of research in the European OE automotive companies, primarily BMW, Porsche and Audi, to develop pistons that meet the engine designer’s latest trends. Where pistons once were simply symmetrically round pieces of metal, they have evolved to the point where there are several different ovalities, two times and three times the amount, are involved in designing high performance pistons,” said McFarland.

Using European markets as R & D in diesel piston technology makes a lot of sense when you consider that fuel prices are much higher than the U.S. and diesel applications account for half of the traffic on the road.

There are several considerations when designing a diesel piston as McFarland explained to us. “Weight can be an issue if you are planning to rev at high RPMs, at high RPMs a heavier piston creates a lot of momentum that creates a load on the connecting rod, wrist pin and bearings. Diesel pistons also have to be able to handle much higher compression pressure and operating temperatures.”

According to McFarland, MAHLE’s new two piece Monotherm Duramax diesel piston is designed for heavy duty, high output engines. The two-piece piston with steel crowns “allow engine builders to be more aggressive with their tunes without having to worry about burning their pistons. This can be a major advantage for tow vehicles that are prone to higher exhaust temperatures,” says McFarland.

MAHLE has offered the Monotherm piston as a single piece steel piston in the past, and it has done well, now we are anxious to see how the two piece version, with its lighter weight and articulating function stacks up.