Federal-Mogul Powertrain has become the first company to bring ultra high-strength iron cylinder liners into series production. Made of 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 100mm and 190mm bore.
“Bore distortion under load makes sealing between the liner and the ring pack more difficult, leading to increased oil consumption and greater wear,” explained Gian Maria Olivetti, chief technology officer, 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,” continued Olivetti. “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.
The off-highway sector construction, agricultural and industrial applications has been first to recognise the benefits of ultra high-strength liners, but Federal-Mogul Powertrain also expects growing interest in the technology from marine, power generation and on-highway heavy-duty engine manufacturers.
Federal-Mogul Powertrain has extensive experience of liner material development and also of the comprehensive simulation and analysis required to optimise the geometry of a new liner application, under different 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.
To ensure that every production liner meets the same high performance standards as the initial samples, Federal-Mogul Powertrain uses advanced high quality manufacturing equipment to optimise tolerance and honing control. Similar emphasis on metrology after manufacture confirms the geometric forms and surface topography.
“We understand that individual applications and markets are driven by different priorities and we cater for each with alternative solutions,” said Dr. Volker Scherer, director liners, Federal-Mogul Powertrain. “For some of our customers, the liner is a commodity where value and local sourcing are key influences; for others, more challenging design targets and load requirements necessitate superior mechanical properties, such as those provided by GOE330”.
“Whichever approach is taken, we are able to support our customers by providing a complete, optimised assembly for the entire power cylinder system, including liner, piston and ring pack.”