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Specialized Lubricant Evaluations
Gasoline Two-Stroke Cycle Lubricants
Concern over energy conservation and environmental
pollution has led to leaner oil-to-fuel ratios, which, in turn, have affected
lubricant requirements. Exhaust emission reduction could contribute to the
two-stroke cycle engine's viability in the near future. The two-stroke cycle
engine provides better power-to-weight ratio, higher specific power output, and
less frictional loss than the four-stroke engine.
The Institute evaluates lubricants used in two-stroke
cycle, air-cooled engines using the ASTM-TC test sequence and JASO standards, which evaluates the
lubricant's ability to:
- Resist combustion chamber deposit-induced
pre-ignition
- Prevent ring sticking
- Inhibit deposit formation
- Reduce scuffing
- Resist spark plug fouling
- Reduce exhaust smoke
SwRI also offers all engine and chemical tests
required to evaluate lubricants for two-stroke, water-cooled engines, including
the National Marine Manufacturers Association TC-W3TM specification tests. These
requirements have led to improved lubricants that exhibit higher levels of
resistance to ring sticking and loss of cylinder compression. In the future,
biodegradability of lubricants may become a significant factor for lubricants
formulated for the boating industry.
For two-stroke, air-cooled engines, the International
Standards Organization (ISO) has recently adopted worldwide test procedures to
evaluate lubricants for exhaust smoke, exhaust system deposits, lubricity, and
piston cleanliness. These test methods, conducted by SwRI, have supplemented the
ASTM-TC specification tests previously used by industry.
With trained personnel and modern laboratory
facilities, SwRI helps the petroleum industry monitor future trends and develop
lubricants that meet current requirements. In addition, SwRI engineering and
technical staff members are available to develop and operate special two-stroke
cycle laboratory tests or to design and coordinate custom field tests to meet
unique requirements.
William A. Buscher, Manager
Tony Hendrix, Research Technologist
Engine Lubricants Research Department
Fuels and Lubricants Research Division
SwRI Technical Divisions
SwRI Home
May 23, 2012
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