Piston Ring Cylinder Liner Tribological Review
Abstract
Piston rings were invented for the intended use in the steam engine in 1852 by British engineer John Ramsbottom1. Ramsbottom reported reduced friction, less blow-by between chambers, and dramatic improvements to efficiency and power. Shortly thereafter, piston rings were adopted for the internal combustion engine, and were found early in development to yield the same efficiency and power benefits. Piston rings have thus been an integral part in improving the practicality, reliability and efficiency of the internal combustion engine. A modern internal combustion engine is generally characterized as either two stroke or four stroke. Premix two stroke engines traditionally have an upper and lower compression ring without an oil control ring2. In lieu of an oil sump, lubrication is achieved by premixing oil and fuel. The oil therefore is sacrificial, and must be continually supplied just as fuel, in a ratio determined by manufacturers specification. The oil and fuel mix is then supplied with air, which travels through the crankcase before being introduced into the combustion chamber during the intake stroke. Oil is deposited on the inside of the crankcase, crank components, piston skirt and cylinder walls during this process, effectively distributing lubricant to the system. During a combustion event, the heavier non-combustible hydrocarbons of the lubricant often leave soot behind. Thus, this type of engine generally has higher concentrations of particulate matter and unburnt hydrocarbons exhausted from the system. Four strokes traditionally have three rings. In addition to the two compression rings of a two stroke engine, four strokes require an oil control ring. This is due to the crankcase also operating as an oil sump. An oil pump pressurizes and distributes the oil to tribological contacting bodies including the cylinder wall / piston ring interface. The top compression ring affords the bulk of the pressure generated by the combustion stroke.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 11, 2018
- Accession Number
- AD1056698
Entities
People
- Allen S. Comfort
- James S. Dusenbury
- Steven J. Thrush
- Talia M. Sebastian
Organizations
- United States Army Tank Automotive Research, Development and Engineering Center