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An organic Rankine Bottoming cycle added to Diesel engines used for long-haul trucks has the potential of improving their peak fuel economy by up to 15% over a typical duty cycle. General Electric has developed a multi-vane rotary expander which has a measured isentropic brake efficiency of 80+% over a wide range of speed and power levels with organic working fluids. High cycle efficiency for design and off-design conditions is achieved with the multi-vane expander. The potential advantages of the multi-vane expander for the Diesel engine bottoming cycle include the elimination of a high speed gear box and the potential for over 80% isentropic engine efficiency. The multi-vane expander is a ruggedly built component running at Diesel engine speed. This paper describes the design and evaluation of a nominal 40 HP multi-vane expander for this application.

A method for measurement of rolling resistance of vehicles using only a single accelerometer measurement has been developed and a simple instrument has been constructed. Results of typical measurements on large, electrically propelled off-highway trucks are discussed.

Today's instrument panel specifications for passenger cars are also applied to most light trucks and vans because internal company standards are dictating that light trucks and vans should approach the occupant safety of existing cars. In this presentation, we will examine the traditional specifications for pre-1988 model year, which center on a few key materials and part performance properties, and the increasing number of specifications which are being called for in 1988 model year and beyond, which require altogether new materials and processing systems. (Throughout this discussion, it should be noted that in referencing “automobiles” we are including light trucks and vans.)

Alternative engine concepts to the advanced high bypass turbofan which have promise of reducing energy consumption including regenerative cycles and other engines with heat exchangers, unconventional engine arrangements such as geared fan engines, and high disc loading turboprops. After initial screening, several concepts were selected for a systematic evaluation of the merits of each relative to a high bypass turbofan based on advanced technology consistent with the mid 1980's time period. Both mission fuel and direct operating cost for typical long range transport missions were considered in the evaluation.

EXPERIMENTAL RESULTS are presented for the effects of water in #2 diesel fuel emulsion on engine performance and combustion for a two cylinder laboratory engine of GE-7FDL series diesel engine parameters. Smoke, NOx, and CO emissions were decreased as the water amount in fuel was increased. At the maximum tested amount of about 30% water, smoke reading was reduced by half (Bosch number) and NOx reduced by 50% at full load. Fuel consumption can be lowered somewhat by adding water also. The potential of fuel savings is about 1-2%. it is more at the lower intake pressure notch 5 load than notch 8 load with higher intake pressure. Both emissions reduction and fuel saving were realized at the expense of increased engine running roughness.

Previous studies had demonstrated the economic and technical feasibility of producing high-quality forgings for aircraft turbine engine parts from hot-isostatically pressed (HIP) Rene 95 powder billets. The present program was aimed at developing a production practice for making HIP + forged turbine discs. The major goal was improved product fabricability and reliability with minimum cost. The program was conducted using argon atomized Rene 95 powder. Experimental studies were conducted to evaluate the effect of powder characteristics, HIP parameters, preform design, and forging conditions on forgeability, microstructure, and mechanical properties. The results of these studies were incorporated into a pilot production run in which 10 disc forgings were made and evaluated. The selected process involved the consolidation of -60 mesh powder to full density by hot-isostatic pressing at a temperature above the γ' solvus temperature.

The advantages of infinitely variable ratio steering and propulsion for track laying vehicles are well known. Studies and demonstrator programs in the past decade have indicated that the hydromechanical transmission has the most promise of providing infinitely variable ratio for military vehicles. In 1966 the Army launched a program to develop the hydromechanical transmission to “production ready” status. This paper describes that program, the transmission selected, and some of the problems encountered in the transition from the demonstrator stage to one of readiness for military application.

THE CONCEPT of an electric motor mounted inside the rim of a large wheel provides several advantages: flexibility, weight and cost reductions, and adaptability to established operating and maintenance patterns. A heavy-duty traction motor drive has been designed that eliminates the need for mechanical drive lines, differentials, and hydraulic torque converters. This paper describes the gear train, lubrication system, brakes, and ventilation of such a drive. Also discussed is the engine-generator set for an electric wheel motor.*

A four-legged, 3000 lb, walking truck test bed has been developed and the test results have proved the feasibility of walking machines. Effectiveness of this control method where the machine mimics man’s arm and leg movements was shown by a variety of maneuverability experiments. Therefore, it has been proved that it is possible to develop this vehicle concept, and the control method involved, to effectively emulate animals in the way they travel on rough terrain. Human perception, judgment, and agility are transmitted through the machine in a manner that lets the operator easily imagine that the machine is merely an effective extension of his own appendages. The human psychomotor action, coupled with the power and ruggedness of the machine, provides a valuable marriage. It opens new vistas not only for rough terrain vehicles but also for a variety of other manipulative machines. Many jobs require the sensing acuity of man but are too tough for the frail human flesh.

The major technological developments which have made possible the trend towards higher temperatures in modern aircraft gas turbine engines are discussed. The relative importance of manufacturing processes, material developments, cooling techniques, analytical design procedures, rupture and cyclic life considerations, and aerodynamic and mechanical design improvements are discussed along with illustrative examples and technical data. The need for a balanced design approach is stressed, and examples are given where trade-offs can be made. It is noted that the advances in aircraft engines during the last 10 years have been based on the evolution of sound engineering principles, extensive component and engine development, and careful consideration of the operational requirements rather than a tremendous breakthrough or revolutionary concept in any one area.

The work reported in this paper has been conducted by a team from GE-Aircraft Engines, GE-CR&D, and Sundstrand under a contract sponsored by the USAF, Wright Laboratories, WPAFB, Contract No. F33615-90-C-2052. The objective of this contract is to prove the feasibility of an Integral Starter/Generator (IS/G) through the preliminary design stage and demonstrate the starter/ generator technology in the externally mounted version utilizing switched reluctance machine technology. This paper will report on the progress for the EIS/G-system through the initial testing stage. Comparison of the finished hardware with the design results presented earlier will lead of the paper. This is followed by the discussion of the early testing results for the system testing. Recommendation on additional testing will be presented at the end of the paper.

This paper describes how the SP-100 Space Reactor Power System (SRPS) can be tailored to meet the specific requirements for a lunar surface power system to meet the needs of the consolidation and utilization phases outlined in the 90-day NASA SEI study report. This same basic power system can also be configured to obtain the low specific masses needed to enable robotic interplanetary science missions employing Nuclear Electric Propulsion (NEP). In both cases it is shown that the SP-100 SRPS can meet the specific requirements. For interplanetary NEP missions, performance upgrades currently being developed in the area of light weight radiators and improved thermoelectric material are assumed to be technology ready in the year 2000 time frame. For lunar applications, some system rearrangement and enclosure of critical components are necessary modifications to the present baseline design.

A new silicone rubber formed-in-place gasketing concept has been developed which has greatly reduced the incidence of warranty oil leaks in engine and drive train components. This concept utilizes a combination of joint configuration and unique cured properties of the silicone formed-in-place gasketing material to achieve leak-free performance over the life of the component.

The General Electric Company has recently been in the process of developing two new turbofan aircraft engines-the TF34 and the F101. The TF34 has been developed for the U.S. Navy's S-3A antisubmarine warfare aircraft and has been selected by Fairchild-Hiller for the U.S. Air Force A-10A; the F101 is being developed for the U.S. Air Force B-1 strategic bomber. Each of the new aircraft programs has the common requirement for subsonic endurance. The S-3A and A-10A requirements include subsonic operation only while the B-1 includes supersonic capability as well as subsonic. This basic mission-mix difference combined with major differences in engine/air vehicle installation features and different levels of technology applied due to the relative chronology in the respective development programs leads to contrasts in the design features of the major components of the engines.

The analysis of exhaust gas is becoming an increasingly important tool in determination of the performance of high temperature combustion systems. Previous methods involving the collection of gas samples in sampling tubes, followed by subsequent laboratory analysis, have been laborious and time consuming. A new on-line gas analysis system has been put into service, which makes a complete analysis every 30 sec directly at the test site. The system involves the use of five process gas chromatographs to measure oxygen, nitrogen, carbon dioxide, carbon monoxide, and hydrogen, plus a hydrocarbon analyzer to determine unburned hydrocarbons. These measurements in conjunction with other operating data permit the calculation of overall combustor performance, as well as identification of local point-by-point conditions at the combustor exit.

Aircraft starting and generating systems heretofore have been largely the result of joining together available components. Recent studies have demonstrated that substantial benefits in weight, cost, size, and performance may be realized through a total system approach. This paper identifies the types of information required, and the methods of system analysis employed, to design an optimized system.

Early flight mission objectives can be met with a Space Reactor Power System (SRPS) using thermoelectric conversion in conjunction with fast spectrum, lithium-cooled reactors. This paper describes two system design options using thermoelectric technology to accommodate an early launch. In the first of these options, radiatively coupled Radioisotope Thermoelectric Generator (RTG) unicouples are adapted for use with a SP-100-type reactor heat source (Deane 1992). Unicouples have been widely used as the conversion technology in RTGs and have demonstrated the long-life characteristics necessary for a highly reliable SRPS (Hemler 1992). The thermoelectric leg height is optimized in conjunction with the heat rejection temperature to provide a mass optimum 6-kWe system configured for launch on a Delta II launch vehicle. The flight-demonstrated status of this conversion technology provides a high confidence that such a system can be designed, assembled, tested, and launched by 1996.

The term “SP-100” is synonymous with a set of technologies that can be utilized to provide long lifetime, reliable, safe space power over the range of kilowatts to megawatts [1] using a nuclear reactor as the heat source. This paper describes recent development progress in a number of technology areas such as fuel, materials, reactivity control mechanisms and sensors. Without exception, excellent technical progress is being accomplished in all areas under development to optimize spacecraft performance characteristics.

This paper describes the design, implementation, and performance test results of an engineering model of the Position Multiplexer (MUX)-Analog Input Processor (AIP) System for the transmission and continuous measurements of Reflector Control Drive position in SP-100. The specially tailored MUX-AIP combination multiplexes the sensor signals and provides an increase in immunity from low frequency interference by translating the signals up to a higher frequency band. The modulated multiplexed signals are transmitted over a single twisted shielded cable pair from the reflector drives located near reactor to the AIP located at the power conditioning/system controller end of the space craft boom. There the signals are demultiplexed and processed by the AIP, eliminating the need for individual cables for each of the twelve position sensors across the boom.

The SP-100 Space Reactor Power System is being developed by GE, under contract to the U.S. Department of Energy, to provide electrical power in the range of 10's to 100's of kW. The system represents an enabling technology for a wide variety of earth orbital and interplanetary science missions, nuclear electric propulsion (NEP) stages, and lunar/Mars surface power for the Space Exploration Initiative (SEI). An effective infrastructure of Industry, National Laboratories and Government agencies has made substantial progress since the 1988 System Design Review. Hardware development and testing has progressed to the point of resolving all key technical feasibility issues. The technology and design is now at a state of readiness to support the definition of early flight demonstration missions. Of particular importance is that SP-100 meets the demanding U.S. safety, performance, reliability and life requirements.