|Oak Ridge National Laboratory|
Materials for High Efficiency Engines
Reaching our 2012 goal of 55% engine efficiency while meeting all EPA emission requirements will likely require low-temperature combustion, either fully implemented HCCI or PCCI technology or, at the least, partial implementation of these advanced combustion technologies. These technologies introduce new challenges for engine materials. High-priority issues include fuel system components, turbochargers and intercoolers, valve-train components, and high-strength cylinder heads and engine blocks. We are working in collaboration with domestic diesel engine suppliers to identify the highest-priority materials needs to enable advanced, low-temperature combustion and to identify, or develop, if necessary, new or improved materials.
Milestones: Evaluate the thermal efficiency of the Caterpillar C15 ACERT engine associated with one new/prototype component or subsystem. (09/09) Design and develop a method to conduct fatigue tests on fuel injector tips with small holes. (6/09) Downselect improved exhaust-valve/seat-insert combinations for prototype testing in diesel engines. (06/09). Measure and compare piezoelectric and mechanical reliabilities of tape-cast and pressed PZT piezoceramics. (09/09)
Materials for High Pressure Fuel Injection Systems
Milestone: Design and develop a method to conduct fatigue tests on small holes. (6/09)
Contacts: Peter Blau, Oak Ridge National Laboratory, 865-574-5377, firstname.lastname@example.org
The demands of meeting new emissions and fuel economy goals have pushed heavy-duty truck diesel exhaust component temperatures higher. While many diesel exhaust valves still operate well at temperatures below 750°C, advanced engine applications are pushing valve temperatures to 850°C or higher. The problem caused by higher temperatures is increased degradation and wear, while the engine-maker demands better performance and durability, at similar cost. The purpose of this new CRADA project is to provide a team between ORNL, Caterpillar and their exhaust-valve and seat-insert suppliers, to combine innovative valve design, advanced alloys, and possibly coatings, for rapid selection and testing. In the first year, Caterpillar provided Ni-based superalloy exhaust valves with normal and accelerated engine and simulation (“Buettner Rig”) wear to ORNL for detailed characterization and analysis. The temperatures of worst wear were identified and evidence for oxidation and wear mechanisms was obtained. Caterpillar provided the matching Co-based alloy seat inserts, and began the team discussions with ORNL and their seat supplier. The second year of the CRADA will follow up with suggested alloy processing and alloy modifications, and produce new valves and seats for testing and wear evaluation.
Milestones: Perform the initial microanalysis of modified valves and/or seats after simulation –rig testing to evaluate wear-reduction. (12/08) Downselect improved exhaust-valve/seat-insert combinations for prototype testing in diesel engines. (06/09).
Contacts: Phil Maziasz, Oak Ridge National Laboratory, 865-574-5082, email@example.com
Objective: The objective of this Cooperative Research and Development Agreement between UT-Battelle, Inc. and Cummins, Inc. is to enable the selection of the best or most appropriate piezoceramic multilayer actuators (PMLAs) from competing candidates for use in Cummins heavy duty diesel fuel injectors, and confidently maximize fuel injection response and injector lifetime as a consequence. The use of PMLAs offers the potential for precise and complex fuel injection, reduction in NOx, PM, and fuel consumption, and achievement of 55% thermal efficiency by 2012. However, the piezoceramics in PMLAs are brittle and can be susceptible to fatigue, but those issues can be managed with successful adaptation of structural ceramic probabilistic design methods whereby first principal stress minimization is achieved. Successful use of PMLAs in heavy-duty diesel engine fuel injectors would then result.
Approach: This project combines in-situ micromechanical testing, microstructural-scale finite element analysis, probabilistic design sensitivity, and structural ceramic probabilistic life prediction methods to systematically characterize and optimally design PZT piezoceramics and piezoelectric stack actuators that will enable maximized performance and lifetime in diesel fuel injectors.
Milestone: Measure and compare piezoelectric and mechanical reliabilities of tape-cast and pressed PZT piezoceramics. (09/09)
Photo of the piezodilatometer that has been fabricated, assembled, and ready for calibration. The valve in the lower left is not shown.
Contact: Hua-Tay Lin, Oak Ridge National Laboratory, 865-576-8857, firstname.lastname@example.org
Applications of advanced materials in diesel engines may enhance combustion and reduce parasitic and thermal losses, thereby improving engine efficiency. Engine components developed from advanced materials, however, require rigorous assessment to assure their reliability and durability in more stringent operating conditions. The objective of this work is to develop and assess various nondestructive evaluation (NDE) methods for characterization of advanced engine components in valvetrain, fuel-injection, and turbo systems to be evaluated in a Caterpillar heavy-duty ACERT experimental engine at ORNL. NDE technologies established at ANL, including optical scanning, infrared thermal imaging, ultrasonics, and X-ray CT, will be further developed for detection of volumetric (e.g., voids), planar (e.g., cracks, debonds, joints) and other types of flaws that may limit the performance of these components. Among the NDE technologies, laser backscatter has been demonstrated successfully for characterization of engine valves made from advanced ceramics and intermetallics, and thermal imaging, either active or passive, can be used to evaluate coatings on cylinder head and monitor heat loss from engine systems. Development in these NDE technologies will be focused on achieving higher spatial resolution and detection sensitivity. This work is collaborated with Caterpillar, Inc. and ORNL.
Contact: Jiangang Sun, Argonne National Laboratory, 630-252-5169, email@example.com
Objective: The purpose of this agreement is to improve diesel engine performance, efficiency, and emissions through the application of materials-enabled technologies. The demands of meeting new emissions and fuel economy goals are continuing to push heavy-duty diesel engine components to higher temperatures and pressures, and, at the same time, require improved durability. These demands often require materials technology solutions to meet the enhanced performance requirements.
This CRADA combines expertise and facilities from the ORNL Materials Science & Technology and Engineering & Transportation Sciences Divisions to empirically evaluate engine and material subsystem performance to further advance engine operation to overcome technical barriers associated with advanced combustion, thermal management and parasitic losses. During FY08, a heavy-duty ACERT engine was installed and operated under baseline conditions. For FY09 the ORNL research team will evaluate at least one component (incorporating a novel material adaptation) on the engine to assess engine efficiency and performance. The component will be examined by materials scientists to further the development of new materials for diesel engines. Computational tools, such as modeling, will be employed to guide component development.
Milestone: Evaluate the thermal efficiency of the engine associated with one new component or subsystem. (09/09)
Contact: Timothy Theiss, Oak Ridge National Laboratory, 865-946-1348, firstname.lastname@example.org
The demands of lower emissions and much better fuel economy have pushed both diesel and automotive exhaust component temperatures higher, particularly turbochargers. Diesel engines require turbochargers, but many gasoline automotive engines are not turbocharged, and automotive turbocharging produces dramatic gains in both fuel economy and engine performance. Turbocharger systems are comprised of the hot-turbine end that powers the system, the cold-compressor end to increase incoming air-pressure, and transition region that connects these dissimilar ends together and holds it onto the engine. Further improvements in turbocharger design, performance, benefits and affordability will be enabled by replacing existing materials with cost-effective advanced materials with better performance and reliability. Critical components for materials upgrade include (but are not limited to) casings, shafts and bearings, impeller wheels, and vanes on both hot- and cold-sides. This CRADA will enable ORNL and Honeywell Turbo Technologies to work together to characterize and identify materials degradation modes and mechanisms in critical components, and then substitute or modify/develop alloys with the improved properties required for each critical component. It will also enable the parties to collaborate to produce and test new prototype components with improved performance to enable rapid commercialization.
Milestones: (1) Review the range of Honeywell turbocharger systems and components, and prioritize the most important components/materials for upgrading. (12/08) (2) Perform the initial microstructure and properties characterization comparing new and engine-exposed components, and identify modes of degradation and alloys for improved performance. (07/09)
Contact: Phil Maziasz, Oak Ridge National Laboratory, 865-574-5082, email@example.com
U.S. Department of Energy • Office of Vehicle Technologies Program