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A 10 KWe dual-mode space power system concept has been identified which is based on INEL's Small Externally-fueled Heat Pipe Thermionic Reactor (SEHPTR) concept. This power system will enhance user capabilities by providing reliable electric power and by providing two propulsion systems; electric power for an arc-jet electric propulsion system and direct thrust by heating hydrogen propellant inside the reactor. The low thrust electric thrusters allow efficient station keeping and long-term maneuvering. The direct thrust capability can provide tens of pounds of thrust at a specific impulse of around 730 seconds for maneuvers that must be performed more rapidly. The direct thrust allows the nuclear power system to move a payload from Low Earth Orbit (LEO) to Geosynchronous Earth Orbit (GEO) in less than one month using approximately half the propellant of a cryogenic chemical stage.

Two-phase capillary loops are being extensively studied as heat collection and rejection systems for space applications as they appear to satisfy several requirements like low weight, low volume, temperature control under variable heat loads and/or heat sink, operation under on ground and micro gravity conditions, simplicity of mounting and heat transfer through tortuous paths. In 1998–2000 Alenia defined and Lavochkin Association developed the Deployable Radiator on the base of honeycomb panels, axial grooved heat pipes and Loop Heat Pipe. It was designed for on-ground testing.

The 1977 Clean Air Act Amendments allow the U.S. Environmental Protection Agency to set high altitude emission standards for 1981-83, but specify that any such standards may not be more stringent than comparable sea level standards -- relative to 1970 emission levels. Since available high altitude emission data from 1970 models were incomplete and controversial, the Motor Vehicle Manufacturers Association contracted with Automotive Testing Laboratories, Inc. to test a fleet of 25 1970 cars. Results of the test program showed average increases in emissions at Denver's altitude, compared to sea level, to be about 30% for evaporative HC, 57 to 60% for exhaust HC, 215 to 247% for CO and -46 to -47% for NOx. Corresponding HC and CO exhaust emission baselines would be 6.4 to 6.6 and 108 to 118 g/mi respectively.

The paper describes a numerical study, supported by experiments, on light aircraft 2-Stroke Direct Injected Diesel engines, typically rated up to 110 kW (corresponding to about 150 imperial HP). The engines must be as light as possible and they are to be directly coupled to the propeller, without reduction drive. The ensuing main design constraints are: i) in-cylinder peak pressure as low as possible (typically, no more than 120 bar); ii) maximum rotational speed limited to 2600 rpm. As far as exhaust emissions are concerned, piston aircraft engines remain unregulated but lack of visible smoke is a customer requirement, so that a value of 1 is assumed as maximum Smoke number. For the reasons clarified in the paper, only three cylinder in line engines are investigated. Reference is made to two types of scavenging and combustion systems, designed by the authors with the assistance of state-of-the-art CFD tools and described in detail in a parallel paper.

BlueStar Advanced Technology Corporation (BATC) as part of its participation in the USAF/NASA Li Ion Battery Development Consortium has developed a candidate 25-Ah cell for the Mars 2001 Lander. Although the capacity and cycle life requirements for this application are relatively modest, the low temperature performance (−20°C) and pulse discharge requirements (60A) are somewhat more challenging. Geometric requirements within the spacecraft also constrain the cell design leading to a cell with an aspect ratio quite different from those 25-Ah Li ion cells previously developed by BATC. The design of this cell and its compliance with the performance requirements of the mission will be discussed.

In order to take full advantage of SiC, a high temperature package for power module using SiC devices was designed, developed, fabricated and tested. The details of the material selection and fabrication process are described. High temperature reliability test and power test shows that the package presented in this paper can perform well at the high junction temperature.

Sundstrand is investigating 270-Vdc/hybrid 115-Vac electrical power generating and distribution systems technology so as to be well prepared to offer such systems for future aircraft applications. The approach taken has been to design, build, and test a representative system that meets or exceeds the tightest of the performance standards as defined by miliary standards. This paper describes a single-channel, 120-kW hybrid system and presents some typical performance data. The dc bus supplies a 30-kVA, 400-Hz, 115-Vac inverter; constant power load banks of up to 150 kW; and a resistive load bank of up to 90 kW. System simulation studies indicated the potential for unstable operation due to the negative impedance of the constant power load in conjunction with the source ripple filter and the load EMI filters. Unstable voltage and current were observed in system testing when the magnitude of the source impedance was not sufficiently below that of the load impedance.

Sundstrand has been investigating 270-Vdc/hybrid 115-Vac electrical power generating systems (EPGS) technology in preparation for meeting the electrical power generating system (EPGS) requirements for future aircraft (1). Systems such as the one being investigated are likely to be suitable for the More-Electric Aircraft (MEA) concepts presently under industry and military study. The present Sundstrand single-channel testbed is being further expanded to better understand the electrical system performance characteristics and power quality requirements of an MEA in which traditional mechanical subsystems are replaced by those of a “more-electric” nature. This paper presents the most recent Sundstrand 270-Vdc system transient performance data, and describes the modifications being made to the 270-Vdc/hybrid 115-Vac testbed.

Innovative Power Solutions (IPS), LLC has developed a 300A and a 500A 28 VDC Brushless Wound Rotor Starter/Generator (S/G) system. These systems are capable of replacing brush type S/G or Air Turbine Starters by presenting an adequate Torque vs. Speed performance. The S/G system developed by IPS consists of the Starter/Generator (Motor/Generator) and S/G Control Unit (SGCU).

The main objective of the current paper was to investigate the fluid flow and pressure loss characteristics of DPF substrates with asymmetric channels utilizing 3-D Computational Fluid Dynamics (CFD) methods. The ratio of inlet to outlet channel width is 1.2. First, CFD results of velocity and static pressure distributions inside the inlet and outlet channels are discussed for the baseline case with both forward and reversed exhaust flow. Results were also compared with the regular DPF of same cell structure and wall material properties. It was found that asymmetrical channel design has higher pressure loss. The lowest pressure loss was found for the asymmetrical channel design with smaller inlet channels. Then, the effects of DPF length and filter wall permeability on pressure loss, flow and pressure distributions were investigated.

A very high power source solution was developed for the Non Line of Sight Launch System Container Launch Unit (NLOS-LS CLU). The power source solution has been shown to be capable of providing the required 72 continuous hours of operation and high power (3560 watts) to sustain launch capability. The power source consists of 18 BB-2590/U batteries connected in parallel in three layers. Several CLU battery systems have been delivered to the PEO and have been well accepted. The Army is using standard rechargeable batteries, is currently being upgraded with SMBus capability and higher capacity lithium-ion cells. For this reason, the CLU power source has been manufactured with SMBus capability. This paper will discuss the performance of one layer of the CLU power source to simulate the whole power load.

A 500 hours endurance test was performed with a heavy-duty engine (Euro IV); MAN type D 0836 LFL 51 equipped with a PM-Kat®. As fuel 100% biodiesel was used that met the European specification EN 14214. The 500 hours endurance test included both the European stationary and transient cycle (ESC and ETC) as well as longer stationary phases. During the test, regulated emissions (carbon monoxide, nitrogen oxides, hydrocarbons and particulate matter), the particle number distribution and the aldehydes emission were continuously measured. For comparison, tests with fossil diesel fuel were performed before and after the endurance test. During the endurance test, the engine was failure-free for 500 hours with the biogenic fuel. There were almost no differences in specific fuel consumption during the test, but the average exhaust gas temperature increased by about 15°C over the time. Emissions changed only slightly during the test.

Offering aircraft fuel efficiency improvements of 30 to 40% over the powerplants it will replace, PW2037 retrofit in the 727-200 Advanced and B-52 aircraft is attracting heightened interest. A comparison of PW2037 technical characteristics with current aircraft powerplants substantiates the improvement potential.The engine installation and modifications necessary for aircraft system compatibility do not impose significant increases in complexity or cost. The resultant improvements in aircraft capability (727 and B-52) and economic viability to airlines (7271 produce aircraft uniquely suited to today's operational requirements and constrained equipment budgets.

New approaches to problems such as noise, temperature control of accessories and equipment in the nacelle, as well as improved safety features, are necessary in a modern high by-pass engine installation. The means of supporting the engine, cowling design, and maintainability features combine to improve the state of the art that a more economic airplane will result.

Flight control technology for 8000 psi has emerged almost simultaneously with new fire-resistant hydraulic fluids, such as MIL-H-83282 and CTFE. A proliferation of industry recommendations has resulted in a wide variety of mechanisms for solving associated actuator design problems, including tighter clearances, special seals, finishes, materials, and many others. As there are few common agreements on the issues, an extensive three-phase test program was undertaken to attempt to corroborate some of these approaches or suggest others that may be better or more cost effective.

An 8000 psi test program was conducted to resolve conflicts and issues surrounding the use of CTFE and MIL-H-83282 fluid with vented and unvented actuator rod seals. Each of the four possible combinations had unique problems and each responded to appropriate corrections including new backup rings designed to operate with standard clearances. It was concluded that all combinations were viable within certain limits. Advantages and disadvantages of each configuration were identified and specific recommendations made for both dynamic and static seals within the context of existing military specifications.

In 1995, the Naval Research Laboratory (NRL) began a program to investigate whether a 90 Ah dependent pressure vessel (DPV) NiH2 battery pack could be a lower volume replacement for a 90 Ah NiH2 IPV spacecraft battery. Nickel Hydrogen (NiH2) dependent pressure vessel (DPV) battery cells are presumed to offer all the features of the NiH2 IPV battery cell with considerably less volume. To achieve this reduction in volume, the DPV cell utilizes a canteen shaped pressure vessel with reduced thickness wall, flat sides and curved ends. The cells can be packaged similar to prismatic nickel cadmium battery cells. Moreover, like NiCd cells, a fully charged DPV cell must rely upon an adjacent battery cell or structure for support and to maintain pressure vessel integrity. Seventeen 90 Ah NiH2 DPV cells were delivered to NR in 1998 for qualification tests. An eleven-cell half battery pack was manufactured and tested to validate the advantages of the DPV design.

The 912 engine is a well known 4-cylinder horizontally opposed 4-stroke liquid-/air-cooled aircraft engine. The 912 family has a strong track record: 40 000 engines sold / 25 000 still in operation / 5 million flight hours annually. 88% of all light aircraft OEMs use Rotax engines. The 912iS is an evolution of the Rotax 912ULS carbureted engine. The “i” stands for electronic fuel injection which has been developed according to flight standards, providing a better fuel efficiency over the current 912ULS of more than 20% and in a range of 38% to 70% compared to other competitive engines in the light sport, ultra-light aircraft and the general aviation industry. BRP engineers have incorporated several technology enhancements. The fully redundant digital Engine Control Unit (ECU) offers a computer based electronic diagnostic system which makes it easier to diagnose and service the engine.

In the frame of the CRYOSYSTEM A-phase study financed by the European Space Agency, AIR LIQUIDE (France) and ORBITAL HYDRAULIC-BREMEN (Germany) have been studying a -183°C freezer to be used on-board the International Space Station for freezing and storing biological samples.

U S Army tactical vehicles are equipped with a wide range of electrical and electronic equipment to support a variety of missions. This equipment typically requires AC input power with varying voltage, power and phasing requirements. Presently, separate inverters with different voltage, power, and phase ratings are necessary to power the equipment, which imposes maintenance and support problems during field deployments. Avionic Instruments Inc. has developed a scalable inverter system that operates from 28V vehicular power and provides outputs that can easily be configured for a variety of load requirements.