RATT^®
Radioactive Tracer Technology
Measuring Real-Time Wear in Operating Engines and Other Mechanical Systems

• High sensitivity

• Cost-effective testing

• 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

• Continuous testing without disassembly for parts inspection

• Ability to measure wear that is not detectable or measurable by other means

SwRI's radioactive tracer technology can gather meaningful wear information in a matter of minutes, whereas conventional test-and-measure procedures can require hundreds of hours to develop a single data point, without the benefits of historical data and trending. Because periodic physical inspection is not required, RATT avoids possible changes in the way materials fit together or in the system's wear state; hence test-to-test continuity is maintained and sequential experiments yield more meaningful results.

Because RATT allows measurement in the parts-per-million to parts-per-billion range, very small changes in wear can be detected accurately and measured quantitatively as the system is repetitively operated over specific test cycles and environmental conditions. This level of sensitivity provides significant cause-and-effect information under both transient and steady-state conditions and allows wear measurements to be routinely made with a high level of confidence.

With RATT, many test conditions and combinations of variables can be investigated simultaneously—in hours rather than weeks or months. This can reduce product development time for a manufacturer.

The use of radioactive tracers allows both identification and quantification of component wear.

	Radioactive tracer measurements show changes of wear with changes of engine speed and load.

The ultimate goal on many projects is to quantify wear and wear rate in response to specific engine operating conditions and specific system parameters.

2007 and 2010 Diesel Engine Emissions Regulations

The 2007 and 2010 diesel engine emissions regulations are causing diesel engine manufacturers to use nonconventional engine control strategies that employ heavy exhaust gas recirculation (EGR) and include early and late fuel injection. Because these strategies might have a negative effect on engine wear and, subsequently, blow-by and loss of oil control, manufacturers need to assess their impact before engines are put into production. Using radioactive tracer technology, these assessments can be obtained in weeks rather than months or years.

	SwRI maps natural gas engine wear as a function of speed, load, coolant temperature, and oil type.

Radioactive Tracer Technology Techniques

Three radioactive tracer techniques are typically used to measure internal combustion engine component wear and wear in other mechanical components.

• Bulk activation (BA)

• Surface-layer activation or thin-layer activation (SLA/TLA)

• Nuclear recoil implantation (NRI)

SwRI selects the appropriate method based on specific test objectives, component material composition, and configuration or site particulars. Bulk activation and SLA/TLA are often employed together to increase the number of wear surfaces that can be interrogated simultaneously. For non-metallic parts, or for metal parts that do not produce suitable radioactive tracers during standard irradiation, wear is measured using radioactive atoms implanted into the test piece by NRI. The white paper, Overview of the Bulk-Activation RATT^® Method, has more details about BA.