VSP News: Uptime Update, Episode 15 – The shift to steel pistons in commercial vehicles

Oct. 5, 2018
Ted Hughes, head of marketing for Mahle Aftermarket, discusses changes to piston technology, and how they impact the heavy duty market.

The need for increased strength on diesel engine parts and components plays a critical role in the development of new vehicle components and systems. In a combustion engine, the purpose of a piston is to transfer force from the cylinder to the crankshaft. As a moving part and critical component to an engine, pistons can take quite a bit of abuse. Due to the even harsher environments of heavy duty diesel engines, coupled with changes to emissions regulations over the last two decades, the materials used for diesel engine pistons have evolved to address these needs. 

Transcription of interview:

Erica Schueller, Fleet Maintenance: Welcome to VSP News: Uptime Update. I am your host Erica Schueller, editor-in-chief of Fleet Maintenance magazine, covering all maintenance, all vehicle classes, all management, all the time.

The need for increased strength on diesel engine parts and components plays a critical role in the development of new vehicle components and systems.

In a combustion engine, the purpose of a piston is to transfer force from the cylinder to the crankshaft. As a moving part and critical component to an engine, pistons can take quite a bit of abuse. Due to the even harsher environments of heavy duty diesel engines, coupled with changes to emissions regulations over the last two decades, the materials used for diesel engine pistons have evolved to address these needs.

We talked with Ted Hughes, head of marketing for Mahle Aftermarket, to discuss the change to piston technology, and how it impacts the heavy duty market.

Ted Hughes, Mahle Aftermatket: In the 100-plus year history of the automobile being on the road, the aluminum piston was the standard for internal engine components. Over time, as the heavy duty market became much more segregated, the demands for something that performed differently and better than aluminum became apparent.

We had more extreme environments, higher heat. Those types of things lead to the need for steel pistons which have emerged over the last few years as really the standard for heavy duty piston technology.

When you add in the recent emissions standards changes, and the demands placed on the engine because of those changes, it really is all steel now.

Schueller, Fleet Maintenance: Companies like Mahle have worked to develop different components to adapt to these industry changes. Hughes discusses how manufacturers are meeting the needs of different fleets.

Hughes, Mahle: The demands for heavy duty engines have changed dramatically, whether you’re talking about the tougher emissions standards by government regulations, or slower rpm (with downspeeding) to increase fuel mileage.

All of them have a different impact on the engine, and in particular, the piston.

As far as current trends go, at Mahle, for example, we’ve developed four different types of steel pistons that represent different strengths and advantages depending on the application, where it’s going to be used. Whether it’s a long-haul truck, or a construction vehicle, the needs for the different engines require different piston technologies.

Schueller, Fleet Maintenance: Regardless of material construction, engines and engine components will require service eventually. But, it’s critical that fleets follow OE guidelines when servicing these systems. Companies like Mahle provide engine kits to assist with this service.

Hughes talks more about this.

Hughes, Mahle: Since the emergence of steel pistons as the accepted material for pistons in heavy duty applications, there’s been a groundswell, if you will, of people that as they tear the engines down for rebuilds, they take the steel pistons out and – based on look or feel – they may not see the damage and think it’s okay to reuse the piston.

At Mahle, this is not something we would always recommend. And if it is going to be done, it must be done in conjunction with the OE specifications every single time.

If it is within accordance of the OE specifications (to reuse the piston), one thing we’ve introduced is the Mahle Heavy Duty Engine Kit, with pistons and without pistons. It’s our way of addressing the emerging trend based on the advancements in steel piston technology.

Schueller, Fleet Maintenance: While the use of steel for manufacturing strong components isn’t changing anytime soon, the development of how these parts are designed will continue to evolve. Hughes provides some details on the evolution of these components.

Hughes, Mahle: Until there is material invented that can outperform or surpass steel with regards to the harsh temperatures and environments in heavy duty engines, what you’ll see for future piston technology is going to be evolutions in the way steel is used in terms of that piston science.

Years ago, when Mahle introduced steel pistons in their line, it was done with the Ferrotherm. That was the initial steel design. Years later, that was joined in the portfolio by the Monotherm. Just recently, we introduced the MonoWeld piston. All of them are driven off of application engineering.

The MonoWeld, for example, has a more advanced production process and the resulting piston is strong enough that a shaker plate’s not required.

That’s the type of stuff from engineering that you’ll see addressing the changing world of the piston.

Schueller, Fleet Maintenance: To read more about the evolution of piston technology in heavy duty engines, go to the link below.

Thank you for tuning in to VSP News Uptime Update, I’m your host Erica Schueller.

Until our next broadcast, keep up with this, and other industry topics, by visiting us online at VehicleServicePros.com.

Read more about the evolution of piston technology in heavy duty engines.