Expenditures For Gasoline

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Figure 4

high pay-off R&D on promising transportation heat engine propulsion conservation technologies has been constructed. This program aims to provide the automotive industry with proof-of-concepts for advanced engine technology with potential for fuel economy improvement on the order of 30%. Similarly the advanced diesel technology efforts are expected to provide the heavy duty transport industry with like fuel economy improvements. Supporting technologies are included in the program with emphasis on the development of a fundamental advanced materials technology base to provide the ceramics industry with the capability of producing reliable and cost effective components for advanced heat engines. A utiliz.ation-oriented fuels data base for heat engine operation on biomass, oil shale and coal derived fuels is also in development in the program.

Basic guidelines used in constructing the heat engine program include the following:

o Provide a maximum industry involvement both in the identification and selection of projects and in the R&D pursuit of technical solutions.

o Design programs to supplement but not duplicate R&D addressed by industry.

o Emphasize proof-of-concept and technology development rather than product design or demonstration o Concentrate on key technology barriers that prohibit industry "going it alone" because of their high risk and long term nature.

o Focus on technology areas with wide applications and high energy conservation potential.

In order to provide an effective and high quality technical oversight, DOE has arranged working agreements with NASA Lewis Research Center to provide contracting and technical management of the major heat engine projects-the Automotive Gas Turbine, the Automotive Stirling Engine and the Heavy Duty Advanced Diesel and with the Oak Ridge National Laboratory to provide technical management for materials and fuels research and development programs.

Major Program Areas

The DOE Heat Engine Propulsion Program is divided into two major program areas- Engine Systems Development and Engine Technology Development. Three sub-programs - the Automotive Gas Turbine, the Automotive Stirling and the Advanced Heavy Duty Diesel - are included in the Engine Systems Development Program. The Ceramic Technology for Advanced Heat Engine Program and the Alternative Fuels Utilization Program are elements of the Engine Technology Development Program. Funding for the total Heat Engine Propulsion Program in FY 1987 was approximately $40 million.

Automotive Gas Turbine

The Automotive Gas Turbine (AGT) program was conceived with the goals of achieving a 30 percent improvement in fuel economy over contemporary spark ignition engined automobiles of equal performance and curb weight, improving the environment through lower CO and HC emissions and providing enhanced alternative fuel capability. To achieve these goals a proof-of-concept approach with experimental engines was taken with two industry teams representing both the gas turbine and automotive industries. The primary technical challenges faced included the development of small, efficient turbomachinery, operation at turbine inlet temperatures in the 2350 F to 2500 F range, the development of reliable high temperature structural ceramic components and the development of low emissions combustor technology.

The following are among the more significant accomplishments thus far achieved in the AGT program.

Automotive Stirling Engine designed (the AGT 100 and AGT 101), fabricated and successfully tested at near design conditions of RPM, turbine inlet temperature (TIT) and horsepower.

o Engine operation with all-ceramic hot-flow-path components was performed for 85 hours at a TIT of 2200 F.

o Proof testing of 137 components in a test bed engine was accomplished and structural ceramics passed over 40 hours of exposure to 2500 F.

o Emissions goals were demonstrated using diesel fuels and methanol in test-bed engines and low emissions were demonstrated with JP-5 fuels in a combustor rig.

Despite the progress made in the program, it became apparent that high temperature structural ceramic development had not progressed to the point that fully reliable ceramic components could be designed and fabricated for turbine application. As a consequence the gas turbine program has been re-oriented to provide a greater focus on ceramic application. This new program called the Advanced Turbine Technology Applications Program (ATTAP) has as its objectives the establishment of reliability of ceramic component designs and materials, the expansion of the experimental materials data base in an operating environment and the development of the analytical tools needed to support industry in the successful application of ceramics to long-life turbine engines. ATTAP will be closely coordinated with DOE's Ceramic Technology for Advanced Heat Engine Program and new and improved materials and technology emanating from that program will be applied where appropriate.

Program goals for the Automotive Stirling Engine (ASE) Program are similar to those for the Gas Turbine with fuel economy improvements on the order of 30 percent, expanded alternative fuel capability and improved emissions being the primary targets of the program. The project began with early proof-of-concept testing of a stationary Stirling engine adapted for automotive installation. Successive engine models were developed to improve fuel economy, vehicle acceleration and engine weight/volume. The first generation MOD I and the upgraded MOD IA engines advanced Stirling Technology to a verified 15 percent improvement in fuel economy with acceptable vehicle acceleration. The second generation MOD II engine currently in development will be installed in a U.S. Postal Service Long Life Vehicle as a final Stirling engine technology demonstration of the project goals.

In addition to the development activity on the MOD II engine, a technology transfer program is also being supported. This program known as the Government and Industry Participation Program (GIPP) provides surplus MOD I engines for additional testing by industry and other government agencies. The government-owned engines are loaned at no charge to voluntary participants. Present participants include NASA, U.S. Air Force, Deere and Co., The American Trucking Associations and Purolator Courier.

Recent project accomplishments i nclude:

o Full MOD II engine system characterization with over 800 hours of engine testing.

o Demonstration of multi-fuel capability of the MOD I engine using gasoline, diesel and JP-4 fuels during a 1000 hour program of mission operation on an Air Force van.

o Analyses indicating favorable fuel economy, emissions and manufacturing costs for the MOD II second generation engine design.

o Installation and test of a first generation MOD I engine in an Air Force pickup truck.

Advanced Heavy Duty Diesel

The objective of this program is to develop a technology base for advanced heavy duty diesel engines used in trucks, buses and other non-highway transportation systems. Goals have been established for attaining a rated specific fuel consumption of 0.25 Ibs/BHP-HR and providing an economically and socially acceptable technology meeting noise and emission standards and broad fuel capabilities while being competitive in capital and maintenance costs. The programmatic approach has been to maintain a strong industry involvement in the planning process while establishing and maintaining an appropriate mix of near term and far term technology projects.

The technical program consists of four interrelated technical disciplines. These are: thermal insulation, friction and wear (tribology), combustion, and advanced thermomechanical systems.

In the area of thermal insulation, the goal is to reduce in-cylinder heat loss by up to 80%. To achieve this reduction the use of thick thermal barrier coatings, solid ceramic inserts, air gaps and hybrid systems combining these approaches are being considered. Programs for the development, design application and test of thick thermal barrier coatings and solid ceramic inserts are presently being supported.

Activity on friction and wear has concentrated on the development and verification of high temperature lubricants capable of operating with top ring reversal temperatures up to

500 C. Both liquid and gas phase approaches are being pursued. Additionally, ion-implementation low friction and wear protective coatings have been tested.

The primary concern in the combustion area has centered on high temperature emissions. Increasingly restrictive Federal emission standards make it imperative that any new diesel technology emanating from the DOE program contribute toward meeting the standards. Several efforts to characterize emissions for the low heat rejection concept are currently underway.

Approaches to advancing diesel thermomechanical systems include as a primary element the development and application of waste heat utilization concepts. The need in this area is to develop an approach that is both effective in reducing fuel consumption and economic in its back pay period. Studies of organic and steam Rankine cycle bottoming systems, diesel/ Rankine cycle integration and turbocharger/turbocompound systems are presently being conducted.

A more detailed description of activity and accomplishments under the Heavy Duty Diesel Program is included in these proceedings in a paper by Jim Wood of NASA Lewis Research Center.

Ceramic Technology for Advanced Heat Engines

The Ceramic Technology for Advanced Heat Engines (CTAHE) program, conducted through Oak Ridge National Laboratory, was established to develop an industrial technology base capable of providing reliable and cost effective high-temperature ceramic components for application to advanced heat engines. It consists of balanced research effort in three areas: (1) materials and processing, (2) data base and life prediction and (3) design methodology.

The objective of the materials and processing research is to develop processing methods that can yield materials with uniform microstructures and high temperature mechanical corrosion-resistant components. Principal research areas include powder synthesis and characterization (to increase uniformity and controllability of properties); processing, characterization and densification of green-state ceramics; and structural, mechanical, and physical properties of dense ceramics.

Research efforts in the data base and life prediction area are focused on the development of techniques, generation of concepts, and acquisition of data on both existing and new ceramic materials necessary to improve mechanical and environmental reliability. They encompass structural qualification procedures and testing for ceramic engine components, making full use of available industrial test rigs for both turbine and diesel engines; detailed study of time-dependent and environmental effects in simulated service environments (in particular, the characterization of the long-term behavior of both existing and new materials); and development of advanced non-destructive evaluation (NDE) methods that can be used in combination with design methodology to generate accurate service-life predictions

Research in design methodology is oriented toward understanding the properties of brittle ceramics under stress well enough to predict accurately their lifetimes in specific engine-component uses. It involves finite element modeling on a microscopic scale, studying static and moving interfaces between ceramics and other ceramics or selected metal alloys, and developing and utiliz.ing advanced statistical representations for new design methodologies tailored to the use of ceramics in advanced heat engines.

Alternative Fuels Utiliz.ation

The use of alternative fuels in place of conventional gasolines and diesel fuels is a means of significantly reducing the nation's dependence on petroleum. To a limited extent, alcohols (mostly ethanol from agricultural sources) blended in gasoline, and natural gas (in a very small number of vehicles) are already displacing petroleum-derived fuels. For the longer-term, it would be desirable to derive transportation fuels from abundant domestic resources such as coal and oil shale.

The primary goal of the Alternative Fuels Utilization Program (AFUP) is to assure the availability of technology for, and eliminate barriers to, the use of alternative transportation fuel options so that industry can bridge temporary and long-term gaps between petroleum supply and demand, and reduce the nation's dependence on petroleum imports by using abundant indigenous resources.

Six classes of fuels are currently addressed in AFUP: (1) new hydrocarbon fuels; (2) synthetic gasoline and distillate fuel (fuels in this category meet current fuel specifications); (3) alcohol fuels; (4) advanced fuels; (5) emergency fuels; and (6) methane and related gaseous fuels. Limited work on advanced fuels (hydrogen) has been carried out part way, consistent with the long-term prospects for supply.

Coordination & Technology Transfer

As is evident from the above sections, the DOE Heat Engine Propulsion Program is divided into two major elements-projects supporting the proof-of-concept of specific types of engines such as the gas turbine, Stirling and diesel and projects which provide research and development of basic technologies broadly applicable to all heat engines; i.e., ceramic materials and alternative fuels.

Effective coordination between these two elements is essential if program goals are to be attained. Typically in the iterative process between these elements, engine designers identify technology needs, as for example material coating requirements. Recognizing these needs coating research and development is directed at relevant improvements which can then be applied to engine components for test verification. If further improvement is required, the cycle is repeated until goals are met.

Bringing engine designers and supporting technology specialists together in workshops such as this or other ways for mutual discussion of engine needs and the technology progress is, we believe, an effective way of stimulating the technology transfer and coordination necessary for program success. As such, we at DOE appreciate the support of this workshop by industry, academia and other government agencies and recognize that this support is vital to the successful pursuit of a meaningful heat engine propulsion R&D program.

Solar Stirling Engine Basics Explained

Solar Stirling Engine Basics Explained

The solar Stirling engine is progressively becoming a viable alternative to solar panels for its higher efficiency. Stirling engines might be the best way to harvest the power provided by the sun. This is an easy-to-understand explanation of how Stirling engines work, the different types, and why they are more efficient than steam engines.

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