|This electronic brochure highlights our
capabilities and activities in the area of Radioactive Tracer Technology.
Please sign our guestbook.
Doug Eberle, Southwest Research Institute.
Radioactive Tracer Technology
Measuring Real-Time Wear in Operating Engines
For 40 years, Southwest Research Institute (SwRI) has used
radioactive tracer techniques to make highly accurate and sensitive real-time wear
measurements in operating engines. These capabilities are particularly important in light
of the harsh operating and environmental conditions imposed on today's high-performance
engines, in which performance as well as low emissions levels increasingly depend on
close-tolerance operation with minimal wear. Using sophisticated instrumentation, SwRI
studies real-time wear, detecting wear and wear rate changes instantly. Advantages of
radioactive tracer measurement techniques include:
- Cost effective tests
- Repeatable measurements
- Real-time wear data
- Meaningful results for short tests
- Easily measured transients
- Identification of cause and effect relationships
- Association of wear with specific design parameters, fuel and
lubricant characteristics, and engine operating conditions
Two radioactive tracer techniques are typically used to measure
internal combustion engine component wear: bulk activation and surface- or thin-layer
activation (SLA/TLA). SwRI selects the appropriate method based on specific test
objectives, component metallurgy, and configuration or site particulars.
The Institute measures wear as a function of lubricant
and engine operation parameters using bulk activated rings and connecting rod bearings in
a test engine.
For bulk activation testing, components are irradiated in a
conventional nuclear reactor and installed in a test engine. As irradiated particles
abrade from the components during engine operation, specific radioisotopes serve as
detectable tracers in the lubricant. SwRI measures radiation from these particles using a
gamma ray spectrometer; radiation is proportional to the mass of the abraded material in
the oil. Multiple isotopes can be measured simultaneously, allowing wear from multiple
parts or surfaces to be measured in a single test.
To measure wear in operating engines, specific
components are first irradiated in a nuclear reactor. During wear testing, abraded
material is measured using the resulting traceable isotopes.
Using bulk radioactive tracer methods, SwRI measures
transient piston ring wear associated with speed and load changes.
Surface- or Thin-Layer Activation
Using SLA/TLA techniques, components are bombarded with a
high-energy beam of charged particles to activate a thin layer of atoms on the component
surface. Wear is measured by monitoring a decrease in the component's radioactivity or an
increase in the radioactivity of debris collecting in a fluid filter.
Using SLA, SwRI measures in situ piston ring
wear as a function of liner surface treatment in a diesel engine.
Radioactive tracer wear testing can be applied to
virtually any metal part that provides suitable isotopes when irradiated. In addition to
engine components, transmission gears and hydraulic pump parts are ideal candidates.
The Institute's radioactive tracer techniques provide
cost-effective, accurate, real-time data, detecting minute wear changes without
disassembly and physical inspection, to study component wear under transient and
Past SwRI radioactive tracer measurement projects have
- Measuring piston ring wear associated with changes in engine
speed, load, and operating temperature; fuel and lubricant quality and type; and internal
and external contamination
- Measuring fuel injector wear associated with component
metallurgy, fuel quality, and contaminant level
- Evaluating diesel engine cylinder liner wear correlating to
liner design, material, and lubrication
- Investigating engine wear sensitivity to fuel, lube oil, and air
- Measuring engine wear associated with dust contamination to
determine relationships between component wear, particle size, and filtration level
- Studying filter performance and filter test procedures using
irradiated standardized test dusts
- Comparing component wear for an engine operating alternately on
natural gas and gasoline
Institute scientists developed a flow-though
radioactive tracer detector system. To determine wear data, the detector is coupled to a
high-speed multichannel analyzer to count and process radiation from tracer isotopes.
This brochure was published in June 1994. For more information
about radioactive tracer technology, contact
Doug Eberle, Principal Engineer,
Engine, Emissions and Vehicle Research Division, Southwest Research Institute, P.O. Drawer 28510, San
Antonio, Texas 78228-0510, Phone (210) 522-5260, Fax (210) 522-4581.
Engine, Emissions and Vehicle Research Brochures
SwRI Technical Divisions