Wear mechanism differences of intake valves within heavy duty combustion engines
2014 (English)Conference paper, Abstract (Other academic)
Today, there is an increasing demand on higher efficiency and lower emissions for heavy duty combustion engines. This puts a lot of strain on the different components of the engine. This work is focused on the intake valve system: the valve and valve seat insert. They need to have a low wear rate to survive for an increased operating time but the design of them is a compromise between high efficiency and low wear rate. At the same time they see less and less particulates in the fuel and emissions due to harder legislation that differs around the world, which may hinder the formation of protective tribofilms.
To deal with the challenge this puts on the developers of the valve system, knowledge is needed about how the tribofilms form and protect the sealing surfaces of the valve and valve seat insert. In an earlier study it was shown that the tribofilms and their wear protecting abilities of the intake valve system vary with different operating conditions regarding allowed emissions from the engine. However, observations from the developers tell not only about differences between engines regarding the wear of the valve system but also sometimes visually large differences of valves coming from the same engine.
In this study, differences within the same engine are analyzed. Valves have been taken from three different engines. The set of valves from each engine differ in visual appearance and wear. The valves have been examined with scanning electron microscopy and energy dispersive x-ray analysis to see the coverage and composition of tribofilms.
The results will be presented and discussed regarding the differences within an engine and how these differences compare to the ones between different engines.
Place, publisher, year, edition, pages
Engineering and Technology
Research subject Engineering Science with specialization in Materials Science
IdentifiersURN: urn:nbn:se:uu:diva-244274OAI: oai:DiVA.org:uu-244274DiVA: diva2:788345
SAE International Powertrain, Fuels & Lubricants Meeting, Birmingham, October 20-23, 2014