Ultra high-strength iron cylinder liners28 August 2016
The increased strength and stiffness of new cylinder liner materials from Federal- Mogul Powertrain, which says it is the first to bring ultra high-strength cast iron cylinder liners into series production, is enabling its OEM customers to develop more efficient and more compact heavy-duty engines. Ultra high-strength materials reduce heavy-duty cylinder liner distortion, leading to lower oil consumption and reduced bore friction, and allow higher combustion pressures.
The off-highway sector – construction, agricultural and industrial applications – was the first sector to use ultra high-strength liners, but with the technology now in series production FMP anticipates growing interest from power generation, marine and on- highway vehicle engine manufacturers.
The liners are made from a special form of compacted graphite iron (CGI). The latest formulation – designated GOE330 – reduces the typical bore distortion under maximum piston side thrust by up to 27 % compared to existing iron materials. It is used in liner applications between 100 mm and 190 mm bore.
“Bore distortion under load makes sealing between the liner and the ring pack more difficult, leading to increased oil consumption and greater wear,” commented Gian Maria Olivetti, chief technology officer at Federal- Mogul Powertrain. “If ring tension is increased to compensate, it leads to higher friction and greater fuel consumption. By developing new liner materials with higher strength and stiffness, we enable our OEM customers to develop more efficient engines, using higher peak cylinder pressures,” he said. “We also make it possible for them to use thinner liners, resulting in more compact engine designs.”
The Young’s modulus of GOE330 is more than 15 % greater than existing high-strength iron liner materials, while at 270 MPa its fatigue strength is approximately one-third higher. Future developments are planned that will achieve even higher levels of strength and stiffness.
Federal-Mogul Powertrain backs its claims with extensive experience of liner material development and also of the comprehensive simulation and analysis required to optimise the geometry of new applications various thermal and mechanical loads. This is supported by rig tests prior to engine application testing, using the company’s in-house designed, hydropulser test bench to reproduce fatigue loads resulting from piston side-thrust.