Showing papers on "Propulsion published in 1992"

Hybrid electric propulsion system

Abstract: A hybrid electric vehicle propulsion system having an external combustion free-piston engine is provided with an integral linear electric current generator and a pulse frequency controller The system includes a power integration processor, a frequency modulator circuit and a pulse width modulator circuit, the power integration processor controls the frequency modulator circuit and the pulse width modulator circuit to produce both a frequency modulated pulsed current and an auxiliary power current which varies in pulse width Both the frequency modulated pulsed current and the pulse width modulated auxiliary current are combined to power an electric drive motor having an integral electronic differential A small auxiliary power source, such as a rechargeable battery pack, is provides the auxiliary current for acceleration and hill climbing power The external combustion engine may burn any pollution free fuel (such as natural gas, alcohol, propane, etc) and runs at a constant peak efficiency speed to generate constant frequency electric current from coils integrated into the engine The generator current is sufficient to propel the vehicle in ordinary driving situations with smooth speed control of the drive motor The propulsion motor combines one fixed stator, and two axially opposed permanent magnet or induction-type rotors, one for each output propulsion shaft

Dynamics and control of hypersonic aeropropulsive/aeroelastic vehicles

Abstract: The guidance and control of hypersonic vehicles is examined by studying the airframe/engine/structural-dynamic interactions of a generic vehicle with scramjet propulsion. The pitch-attitude dynamics are described for the vehicle configuration that can sustain hypersonic flight at near-orbital altitudes. These aerospacecraft have strong airframe/engine/elastic coupling in attitude dynamics and engine responses with static instability with respect to pitch. An integrated airframe-engine control system is presented for the control of the system's strong aeropropulsive/aeroelastic coupling. The control methodology utilizes feedback of measured/synthesized values of angle of attack, blended pitch rate, thrust, and combustor-inlet pressure. The multiinput/multioutput engine controller requires high-bandwidth actuation of the fuel-flow control and the effective diffuser ratio. The proposed control laws do not provide optimized performance in terms of pitch response suggesting that additional control crossfeeds and filtering is needed.

Propulsion system for an aircraft providing V/STOL capability

Abstract: The invention is a propulsion system for powering an aircraft in both vertical and horizontal flight modes. In detail, the invention includes a pair of ducted lift fans mounted in the aircraft for providing thrust in the vertical flight mode. A pair of ducted cruise fans are mounted in the aircraft for providing thrust in the horizontal flight mode. Two sets of turboshaft engines are mounted in the aircraft with each of the sets comprising a plurality of the turboshaft engines, each turboshaft engine including an output shaft and having an optimal power output sufficient for powering one of the pair of ducted cruise fans in the horizontal flight mode. Each of the sets includes a sufficient number of the turboshaft engines to provide an optimal power output for powering one of the pair of ducted lift fans and one of the pairs of ducted cruise fans the vertical flight mode. A shafting system is mounted in the aircraft for coupling all of the turboshaft engines to the pairs of ducted fans. A first decoupling system is connected to the shafting system for decoupling the pair of ducted lift fans from the sets of turboshaft engines. Finally, a second decoupling system is connected to the shafting system for individually decoupling each of the turboshaft engines from the shafting system.

Metal- and intermetallic-matrix composites for aerospace propulsion and power systems

Abstract: Successful development and deployment of metal-matrix composites and intermetallic- matrix composites are critical to reaching the goals of many advanced aerospace propulsion and power development programs. The material requirements are based on the aerospace propulsion and power system requirements, economics, and other factors. Advanced military and civilian aircraft engines will require higher specific strength materials that operate at higher temperatures, and the civilian engines will also require long lifetimes. The specific space propulsion and power applications require hightemperature, high-thermal-conductivity, and high-strength materials. Metal-matrix composites and intermetallic-matrix composites either fulfill or have the potential of fulfilling these requirements.

Multidisciplinary propulsion simulation using NPSS

Abstract: The current status of the Numerical Propulsion System Simulation (NPSS) program, a cooperative effort of NASA, industry, and universities to reduce the cost and time of advanced technology propulsion system development, is reviewed. The technologies required for this program include (1) interdisciplinary analysis to couple the relevant disciplines, such as aerodynamics, structures, heat transfer, combustion, acoustics, controls, and materials; (2) integrated systems analysis; (3) a high-performance computing platform, including massively parallel processing; and (4) a simulation environment providing a user-friendly interface. Several research efforts to develop these technologies are discussed.

Space Propulsion by Fusion in a Magnetic Dipole

Abstract: The unique advantages of fusion rocket propulsion systems for distant missions are explored using the magnetic dipole configurations as an example. The dipole is found to have features well suited to space applications. Parameters are presented for a system producing a specific power of kW/kg, capable of interplanetary flights to Mars in 90 days and to Jupiter in a year, and of extra-solar-system flights to 1000 astronomical units (the Tau mission) in 20 years. This is about 10 times better specific power performance than nuclear electric fission systems. Possibilities to further increase the specific power toward 10 kW/kg are discussed, as is an approach to implementing the concept through proof-testing on the moon. 20 refs., 14 figs., 2 tabs.

Semi-hybrid electric automobile

Abstract: A semi-hybrid electric automobile includes a compartment, adapted to receive an easily removable fuel propulsion unit therein, and a transmission, adapted to establish a torque-transmitting connection between an output shaft of a fuel propulsion unit, placed in a predetermined position in the compartment, and a drive axle of the automobile.

An integrated analytical aeropropulsive/aeroelastic model for the dynamic analysis of hypersonic vehicles

Abstract: The development of an approach to the determination of the dynamic characteristics of hypersonic vehicles which is intentionally generic and basic is given. The approach involves a 2D hypersonic aerodynamic analysis utilizing Newtonian theory, coupled with a 1D aero/thermoanalysis of the flow in a scramjet-type propulsion system. In addition, the airframe is considered to be elastic, and the structural dynamics are characterized in terms of a simple lumped-mass model of the invacuo vibration modes. The vibration modes are coupled to the rigid-body modes through the aero/propulsive forces acting on the structure. The control effectors considered on a generic study configuration include aerodynamic pitch-control surfaces, as well as engine fuel flow and diffuser area ratio. The study configuration is shown to be highly statically unstable in pitch, and to exhibit strong airframe/engine/elastic coupling in the aeroelastic and attitude dynamics, as well as the engine responses.

Microwave electrothermal propulsion for space

Abstract: The microwave electrothermal thruster (MET) is attractive for medium- or high-power spacecraft propulsion. A propellant gas is heated by passing it through a microwave plasma discharge created in a resonant cavity by tuning either the TM

Drive system for efficient vehicle propulsion

Abstract: A vehicle drive system which consists of a piston engine prime power source combined with a high inertia acyclic generator used in conjunction with a D.C. motor to provide a bi-directional variable speed transmission of power between the load and the energy source. Sufficient energy accumulates in the inertia of the generator rotor to provide intermittent quantities of energy for acceleration of the vehicle. In this manner, highly efficient engines not presently suitable for use in vehicle propulsion can be utilized as well as the recouping of kinetic energy (regenerative braking) usually lost in heat dissipation by the friction brakes.

Throttle lever position sensor for two-stroke fuel injected engine

Abstract: A marine propulsion device comprising a propulsion unit which is adapted to be mounted on a boat and which includes a propeller shaft and an internal combustion engine drivingly connected to the propeller shaft, the engine including engine block structure having a combustion chamber and defining an air intake passage communicable with the combustion chamber, a throttle plate movably supported by the engine block structure and located in the air intake passage, structure for moving the throttle plate in response to movement of an operator control member, and structure supported by the engine block structure for providing a signal indicating the position of the control member independent of the position of the throttle plate.

Autonomous propulsion within a volume of fluid

Abstract: Energy is collected from temperature differentials in a volume of fluid and the energy is used for autonomous propulsion in the fluid.

Laser Propulsion Research Status and Needs

Abstract: Laser propulsion consists of using energy from a remotely located laser to heat a low-molecular-weight gas to extremely high temperature and then expand the gas through a nozzle to provide thrust. Because of the potential for high specific impulse with adequate thrust to provide reasonable transit times, laser propulsion can be considered for a wide range of mission applications. This article is an overview of the status of continuous laser propulsion and is based on discussions with the research community and a review of recent literature. It describes some of the challenges and opportunities for close collaboration among fluid mechanics, optics, and plasma physics basic research areas. 58 refs.

Space transfer with ground-based laser/electric propulsion

Abstract: A new method of providing power to space vehicles consists of using ground-based lasers to beam power to photovoltaic receivers in space. This can be used as a power source for electrically propelled orbital transfer vehicles.

Self-traveling robotic vehicle with inclinable propulsion units

Abstract: A self-traveling robotic vehicle having inclinable tracklaying propulsion units for operating in a hostile environment. Each propulsion unit has a track, a built-in propulsion drive for driving the track, and a built-in inclination drive for inclining the propulsion unit as required by rotating it about a transverse axis. Each propulsion unit is readily removable and therefore replaceable in the event of failure or damage to a particular propulsion unit. The vehicle is capable of movement along non-horizontal and rough surfaces while maintaining the stability of the vehicle body and any load that it might be carrying. The body of the vehicle does not comprise any mechanical parts. The vehicle is particularly useful in the nuclear industry.

Airship and method for controlling its flight

Abstract: A non-rigid airship is provided which includes a gas envelope having propulsion units mounted on either side thereof. Thrust emanating from the propulsion units is deflectable to control at least the vertical positioning of the airship. Horizontal positioning of the airship may be controlled by varying the relative thrust of the propulsion units. A method is also provided for controlling the flight path of an airship. The method includes providing propulsion units on opposite sides of the airship and deflecting the thrust of the propulsion units to control vertical placement of the airship. Horizontal placement of the airship may be carried out by varying the relative thrust of the propulsion units.

Auxiliary propulsion drive for sailing yacht - uses electric motor coupled to battery recharged via IC engine, solar cells and wind or water powered turbine

Abstract: The propulsion drive uses an electric motor driving a propeller screw (18), which is supplied via a rechargeable battery. The latter is selectively charged via a generator (25) driven by an i.c. engine (24) and/or via solar cells (34) and/or via a wind-, or water-powered generator (18). The battery and the first of the latter generators (25) can be used to operate auxiliary devices within the yacht, e.g. navigation, lighting, heating or cooking devices. Pref. the i.c. engine (24) and the generator are combined, the battery divided into a number of battery modules. ADVANTAGE - Reduced battery size and weight.

Propulsion system for a magnetically movable vehicle

Abstract: A propulsion system for a magnetically movable vehicle includes at least one means for producing a horizontal magnetic field mounted to the vehicle; a conductor adjacent to, but not in physical contact with, the means for producing a horizontal magnetic filed; and means for passing direct current through the conductor; wherein, the conductor is oriented so that the current passing through the conductor will interact with the horizontal magnetic field to generate a linear force sufficient to move the vehicle.

A neural network approach to failure diagnostics for underwater vehicles

Abstract: The author addresses the proposed use of Kalman filters and artificial neural networks to provide the detection and isolation of impending system failures. Such system health diagnosis is necessary for the overall success of mission controllers for autonomous underwater vehicles (AUVs). Two examples of network designs are given. The first addresses the identification of anomalous changes to the vehicle's acceleration behavior resulting from possible propulsion system changes or loss of propulsion efficiency from fouling. The second example relates to the identification of excessive frictional loads in the propulsion drive train that may cause motor failure. In each case, the training method and the resulting decision surface characterization of the networks so designed are described. >

Compound helicopter with engine shaft power output control

Abstract: A compound helicopter includes a main sustaining rotor for hover and low speed flight, a propeller for providing propulsion in high speed flight and an engine. Engine output power is controlled so as to ensure efficient use of available power in both modes of operation. A preferred form of control includes a variable area exhaust nozzle from a gas turbine engine which has the advantage also in providing an augmenting jet thrust during high speed flight.

Stationary plasma thruster evaluation in Russia

Abstract: A team of electric propulsion specialists from U.S. government laboratories experimentally evaluated the performance of a 1.35-kW Stationary Plasma Thruster (SPT) at the Scientific Research Institute of Thermal Processes in Moscow and at 'Fakel' Enterprise in Kaliningrad, Russia. The evaluation was performed using a combination of U.S. and Russian instrumentation and indicated that the actual performance of the thruster appears to be close to the claimed performance. The claimed performance was a specific impulse of 16,000 m/s, an overall efficiency of 50 percent, and an input power of 1.35 kW, and is superior to the performance of western electric thrusters at this specific impulse. The unique performance capabilities of the stationary plasma thruster, along with claims that more than fifty of the 660-W thrusters have been flown in space on Russian spacecraft, attracted the interest of western spacecraft propulsion specialists. A two-phase program was initiated to evaluate the stationary plasma thruster performance and technology. The first phase of this program, to experimentally evaluate the performance of the thruster with U.S. instrumentation in Russia, is described in this report. The second phase objective is to determine the suitability of the stationary plasma thruster technology for use on western spacecraft. This will be accomplished by bringing stationary plasma thrusters to the U.S. for quantification of thruster erosion rates, measurements of the performance variation as a function of long-duration operation, quantification of the exhaust beam divergence angle, and determination of the non-propellant efflux from the thruster. These issues require quantification in order to maximize the probability for user application of the SPT technology and significantly increase the propulsion capabilities of U.S. spacecraft.

Propulsion system for a V/STOL aircraft

Abstract: The invention is a propulsion system for powering an aircraft in both vertical and horizontal flight modes. In detail, the invention comprises a gas-driven ducted lift fan mounted in the aircraft for providing thrust in the vertical flight mode. A turbofan engine is mounted in the aircraft that comprises a fan section for providing thrust in the horizontal flight mode and a turboshaft engine having an output drive shaft coupled to the fan section for driving same. A gas transfer duct is mounted in the aircraft having a first end adapted to receive exhaust air from the fan section and a second end coupled to the lift fan. A turbocompressor is mounted in the transfer duct and a combustor is mounted in the transfer duct between the turbocompressor and the lift fan, the combustor for receiving and burning fuel and providing combustion gases for driving the ducted left fan. A shafting system couples the turbocompressor to the output shaft of the turboshaft engine. A decoupling system is connected to the shafting system for decoupling the turbocompressor from the output shaft of the turboshaft engine.

Application of Taguchi methods to dual mixture ratio propulsion system optimization for SSTO vehicles

Abstract: The application of advanced technologies to future launch vehicle designs would allow the introduction of a rocket-powered, single-stage-to-orbit (SSTO) launch system early in the next century. For a selected SSTO concept, a dual mixture ratio, staged combustion cycle engine that employs a number of innovative technologies was selected as the baseline propulsion system. A series of parametric trade studies are presented to optimize both a dual mixture ratio engine and a single mixture ratio engine of similar design and technology level. The effect of varying lift-off thrust-to-weight ratio, engine mode transition Mach number, mixture ratios, area ratios, and chamber pressure values on overall vehicle weight is examined. The sensitivity of the advanced SSTO vehicle to variations in each of these parameters is presented, taking into account the interaction of each of the parameters with each other. This parametric optimization and sensitivity study employs a Taguchi design method. The Taguchi method is an efficient approach for determining near-optimum design parameters using orthogonal matrices from design of experiments (DOE) theory. Using orthogonal matrices significantly reduces the number of experimental configurations to be studied. The effectiveness and limitations of the Taguchi method for propulsion/vehicle optimization studies as compared to traditional single-variable parametric trade studies is also discussed.

Combined heat engine and electric motor propulsion unit for vehicle - has electric motor mounted directly on normal gearbox and connected to secondary shaft via belt or gear train

Abstract: A vehicle equipped with a transversely mounted internal combustion engine (5) has an electric motor (7) mounted directly on the casing of its gearbox (14). The internal combustion engine (5) drives the primary shaft (10) of the gearbox and the electric motor (7) drives the secondary shaft (11) through a belt or gear train. The secondary gearbox shaft (11) drives the front wheels of the vehicle (2a,2b) through a reduction gear (12,13) and differential. On the electric motor drive there are no losses in the gearbox or due to driving the internal combustion engine. USE/ADVANTAGE - Vehicle using e.g heat engine on long journeys and electric motor when in urban environment. Provides simple, compact heat engine or electric motor drive for vehicle and avoids mechanical losses in gearbox when using electric drive.

Electric-hydraulic car

Abstract: An electric car is powered from a primary power source in the form of a three-phase parallel resonant electric motor operated at a constant speed (the speed of resonance). The electric motor is provided with operating power from an invertor coupled to storage batteries in the electric car. The motor drives a main hydraulic pump, which is hydraulically connected with a pair of variable displacement drive motors, each connected to different drive wheels on opposite sides of the vehicle. The fluid flow through the pump is varied from 0% to 100% to control the speed of operation of the drive motors connected to the drive wheels of the vehicle.

Application of Taguchi methods to propulsion system optimization for SSTO vehicles

Abstract: The application of advanced technologies to future launch vehicle designs would allow the introduction of a rocket-powered, single-stage-to-orbit (SSTO) launch system early in the next century* For a selected SSTO concept, a dual mixture ratio, staged combustion cycle engine was selected as the baseline propulsion system. A series of parametric trade studies are presented to optimize both a dual mixture ratio engine and a single mixture ratio engine of similar design and technology level. The effect of varying lift-off thrust-to-weight ratio, engine mode transition Mach number, mixture ratios, area ratios, and chamber pressure values on overall vehicle weight is examined. The sensitivity of the advanced SSTO vehicle to variations in each of these parameters is presented, taking into account the interaction of each of the parameters with each other. This parametric optimization and sensitivity study employs a Taguchi design method. The Taguchi method is an efficient approach for determining near optimum design parameters using orthogonal matrices from design of experiments (DOE) theory. Using orthogonal matrices significantly reduces the number of experimental configurations to be studied. The effectiveness and limitations of the Taguchi method are also discussed.

Development of a Preswirl Stator-Propeller System for Improvement of Propulsion Efficiency : a Symmetric Stator Propulsion System

Abstract: A series of design, theoretical analysis and model test procedures is presented for the development of an axisymmetric stator-propeller system A preswirl stator is located in front of a propeller in order to improve the propulsion efficiency by cancellation of the slip stream rotational velocity due to the propeller Model test results show that propulsion efficiency gain due to the symmetric stator-propeller system is about 3% compared to the single propeller This efficiency gain would increase for full scale application since the pressure drag coefficient of the stator would decrease due to increasement of turbulent intensity behind the hull wake and increasement of Reynolds number