Showing papers on "Propulsion published in 2004"

Electric Sail for Spacecraft Propulsion

Abstract: 3Heiser, W H, Pratt, D T, with Daley, D H, and Mehta, U B, “Hypersonic Airbreathing Propulsion,” AIAA Education Series, AIAA, Washington, DC, 1994, pp 334–370 4Chinzei, N, Komuro, T, Kudo, K, Murakami, A, Tani, K, Masuya, G, and Wakamatsu, Y, “Effects of Injector Geometry on Scramjet Combustor Performance,” Journal of Propulsion and Power, Vol 9, No 1, 1993, pp 146–152 5Chinzei, N, Masuya, G, Kudo, K, Murakami, A, and Komuro, T, “Experiment on Multiple Fuel Supplies to Airbreathing Rocket Combustors,” Journal of Propulsion and Power, Vol 3, No 1, 1987, pp 26–32

Electric vehicles charge forward

Abstract: This article reviews the status of electric vehicles/hybrid electric vehicles (EV/HEVs) worldwide and their state of the art, with emphasis on the engineering philosophy and key technologies. The importance of the integration of technologies of automobile, electric motor drive, electronics, energy storage and controls, and the importance of the integration of society strength from government, industry, research institutions, electric power utilities, and transportation authorities are addressed. The challenged of EV commercialization is discussed. EV is a multidisciplinary subject involving broad and complex aspects. However, it has core technologies; chassis and body technology, propulsion technology, and energy source technology. The electric propulsion system is the heart of the EV. It consists of motor drive, transmission and controller, plus the integration with engine power train in the case of the HEV.

Application of direct drive wheel motor for fuel cell electric and hybrid electric vehicle propulsion system

Abstract: This paper presents a gearless wheel motor drive system specifically designed for fuel cell electric and hybrid electric vehicle propulsion application. The system includes a liquid-cooled axial flux permanent-magnet machine designed to meet the direct-drive requirements. The machine design implements techniques to increase the machine inductance in order to improve machine constant power range and high-speed efficiency. The implemented technique reduces machine spin loss to further improve efficiency. The machine design also optimizes the placement of magnets in the rotor to reduce cogging and ripple torque. An original cooling system arrangement based on the use of high thermal conductivity epoxy joining machine stator and liquid-cooled aluminum casing allows the very effective removal of machine power loss. Design details and experimental results are presented

Combined optimisation of design and power management of the hydraulic hybrid propulsion system for the 6 × 6 medium truck

Abstract: Hybrid propulsion systems are one of the critical technologies on the roadmap to future ultra-efficient trucks. While there is a significant body of work related to hybrid passenger cars and light ...

High speed propulsion: Performance advantage of advanced materials

Abstract: High-speed air breathing propulsion systems have many attractive military and civil applications. The high propulsive efficiency of these systems allows the exploitation of speed, distance, and bigger payloads, or any combination of the three. The severe operating conditions of these systems require particular attention to overall thermal management of the engine/air-frame. Fuel-cooling the engine structure is a viable way of maintaining thermal balance over a range of flight conditions. Air Force applications have focused on using endothermic hydrocarbon fuels to address this issue because of their compatibility with the military operations. Recent ground tests of scramjet engines have demonstrated adequate performance utilizing state-of-the-art technology in materials. This progress has paved the way for an expendable flight test vehicle in the near future. In order to take full advantage of the capabilities of this propulsion system, advances in fuel-cooled structures, high temperature un-cooled materials, and increased heat capacity of hydrocarbon fuels will be needed to enable expendable systems to reach higher Mach numbers. An additional benefit would be realized in future reusable systems.

Nonlinear robust control design for levitation and propulsion of a maglev system

Abstract: A nonlinear robust control design for the levitation and propulsion of a magnetic levitation (maglev) system is presented. The maglev dynamics under consideration are nonlinear and contain uncertain dynamics including negative damping due to eddy currents. The proposed recursive controller is designed using nonlinear state transformation and Lyapunov's direct method in order to guarantee global stability for the nonlinear maglev system. Simulation results are provided to show the effectiveness of the proposed control design.

Six -DOF Modeling and Simulation of a Generic Hypersonic Vehicle for Conceptual Design Studies

Abstract: This paper covers the development of a CFD -based Six Degrees of Freedom simulation of a generic hypersonic vehicle [1]. The model and simulation are being developed to support conceptual design studies of hypersonic vehicles with multiple cycle engines. This includes both air breathing and rocket propulsion models. This work is supporte d by the NASA grant # NCC4 -158, in support of their emphasis on new aerospace vehicle concepts and hypersonic technologies. A description of the aerodynamic and propulsion system models developed is included in this paper.

Marine vessel running controlling apparatus, marine vessel maneuvering supporting system and marine vessel each including the marine vessel running controlling apparatus, and marine vessel running controlling method

Abstract: A marine vessel running controlling apparatus controls running of a marine vessel and includes a pair of propulsion systems which respectively generate propulsive forces on a rear port side and a rear starboard side of a hull, and a pair of steering mechanisms which respectively change steering angles defined by directions of the propulsive forces with respect to the hull. The apparatus includes a target combined propulsive force acquiring section, a target movement angle acquiring section, a steering controlling section which controls the steering angles of the respective steering mechanisms such that a turning angular speed of the hull is substantially equal to a predetermined target angular speed, a target propulsive force calculating section which calculates target propulsive forces to be generated from the respective propulsion systems based on the target combined propulsive force, the target movement angle and the steering angles of the respective steering mechanisms, and a propulsive force controlling section which controls the respective propulsion systems so as to attain the target propulsive forces.

History, philosophy, physics, and future directions of aircraft propulsion system / inlet integration

Abstract: This work provides a historical perspective of the developments of propulsion system inlet/engine integration. The flow physics of inlet distortion are discussed, along with the stability effects on the engine compression systems. Throughout the document, both commercial and military applications are considered. Developments in analyses from the original works characterizing inlet distortion, the use of distortion descriptors and early modeling concepts, and the modeling and simulation required today are reviewed. The special requirements and testing techniques necessary to adequately describe inlet distortion and the effects on the propulsion system are summarized. The aspects of pressure distortion, temperature distortion, and swirl are addressed and the physics of interaction described. The compression system response to different types of distortion is discussed with the interaction with various compression system components and designs explained. Axial and centrifugal compressors are covered, as the resulting physics of the inlet distortion effects on each has a different characteristic. An overview of the necessary flow physics to consider in the integration of compression systems in both low and high-Mach number applications is presented.Copyright © 2004 by ASME

Power transmitting apparatus for hybrid vehicle

Abstract: The present invention provides a power transmitting apparatus that uses a small configuration to efficiently carry out various forms of propulsions such as a speed change propulsion and even an EV propulsion (electric propulsion) including a series type EV propulsion. The power transmitting apparatus includes a clutch 8 that connects and disconnects rotation transmissions between an output shaft 1 a of an engine 1 and an input shaft 4 r of one 4 of two power distributors 4 and 5 to which a rotational drive force is transmitted by the engine 1, a clutch 9 that connects and disconnects rotation transmissions between one of two output shafts 5 c, 5 c of the power distributor 5 and a power output shaft 12, and rotation regulating means 10 and 11 that properly inhibit rotation of the input shaft 4 r of the power distributor 4 and rotation of the output shaft 5 c of the power distributor 5. Motors 6 and 7 apply torques to an output shaft 4 s of the power distributor 4 and an output shaft 5 s of the power distributor 5, respectively.

A survey of propulsion options for cargo and piloted missions to Mars.

Abstract: In this paper, high-power electric propulsion options are surveyed in the context of cargo and piloted missions to Mars. A low-thrust trajectory optimization program (RAPTOR) is utilized to analyze this mission. Candidate thrusters are chosen based upon demonstrated performance in the laboratory. Hall, self-field magnetoplasmadynamic (MPDT), self-field lithium Lorentz force accelerator (LiLFA), arcjet, and applied-field LiLFA systems are considered for this mission. In this first phase of the study, all thrusters are assumed to operate at a single power level (regardless of the efficiency-power curve), and the thruster specific mass and powerplant specific mass are taken to be the same for all systems. Under these assumptions, for a 7.5 MW, 60 mT payload, piloted mission, the self-field LiLFA results in the shortest trip time (340 days) with a reasonable propellant mass fraction of 57% (129 mT). For a 150 kW, 9 mT payload, cargo mission, both the applied-field LiLFA and the Hall thruster seem reasonable choices with propellant mass fractions of 42 to 45 % (7 to 8 mT) . The Hall thrusters provide better trip times (530-570 days) compared to the applied-field LiLFA (710 days) for the relatively less demanding mission. Nomenclature

High performance VTOL convertiplanes

Abstract: A single-tilt-rotor VTOL airplanes have a tiltable rotor attached to an elongated power pod containing the collective and cyclical pitch mechanism, and transmission. The power pod is pivotably attached to a base that is slidably mounted on a pair of slotted guide beams attached on top of the roof of the fuselage. The guide beams run longitudinally from the front of the aircraft to past the center of gravity (CG) of the aircraft in order to transport the power pod from the front section to the center section when converting from the horizontal cruising mode to the VTOL mode. In the horizontal cruising mode, the power pod perched horizontally on top of the fuselage front section with sufficient clearance for the rotor to rotate in front of the aircraft. Upon transitioning to the VTOL mode, a telescopic actuator is used to pivot the power pod vertically while a cable-winch system is used to move the entire power pod and base assembly rearwardly to stop at the center of gravity of the aircraft, and vice versa, thus allowing the power pod to travel significantly rearward and forward as required for proper balancing of vertical lift as the power pod pivots 90 degrees during transition from VTOL mode to the cruising mode. A single piston engine, or a single or pair of turbofan engines, mounted slightly to the rear of the CG, have drive shafts that can be clutched and mated onto respective receiving shaft from the transmission within the power pod in order to power the tiltable rotor. The engine is also attached to a propeller for horizontal propulsion, or if turbofan engines are used, jet thrust is generated for horizontal cruise. A small anti-torque rotor or ducted fan toward the tail of the aircraft is mechanically coupled to the engine via a drive shaft to provide the necessary side-way thrust to overcome the main rotor's torque. In the horizontal cruising mode, the tiltable rotor is allowed to windmill slowly at a minimum rotational speed necessary to maintain the integrity of the rotor blades. The same propulsion principle can be applied to VTOL airplanes having more than one tiltable rotor, thereby can potentially increase the speed, range and reliability of current twin-wing-mounted-tilt-rotor aircraft. A pair of high-aspect-ratio wings on both sides of the fuselage provide highly efficient lift during cruising flight with very little induced drag. Conventional horizontal and vertical tail planes are used for directional stability in the cruising mode.

Electric propulsion system

Abstract: Disclosed is a propulsion system for an electric car or other vehicle with potentially better performance—power, efficiency, range—than a gasoline vehicle, at a competitive cost. The motor control system can dynamically adapt to the vehicle's operating conditions (starting, accelerating, turning, braking, cruising at high speeds) and other inputs and parameters. That consistently provides better performance. Isolating the vehicle's motor or generator electromagnetic circuits allows effective control of more independent parameters. That gives great freedom to optimize. Adaptive motors and generators for an electric vehicle are cheaper, smaller, lighter, more powerful, and more efficient than conventional designs. An electric vehicle with in-wheel adaptive motors delivers high power with low unsprung mass and high torque and power-density. Total energy management of the vehicles entire electrical system allows for large-scale optimization. An adaptive architecture improves performance of a wide variety of vehicles, particularly those that need optimal efficiency over a range of operating conditions.

Conceptual Design of an AUV Equipped with a Three Degrees of Freedom Vectored Thruster

Abstract: The early stages of design and simulation of a new concept, autonomous underwater vehicle equipped with vectored thrusters is investigated. The opportunity to increase the research effort in innovative solutions for AUV propulsion and guidance systems is related to the state-of-the-art analysis. The dynamics of submersibles is briefly recalled, to justify the choice to equip the vehicle with a three degrees of freedom mechanism capable to orient both the propeller and the stabilising tail-fins. The vehicle presented has to be considered as a “concept submersible”, that needs further improvements and tuning to become a completely running test-bench for navigation system assessment. A tailored simulation package and results are also described, in order to perform a wide ranging numerical test campaign to foresee life cycle behaviour.

Application of polypyrrole actuators: feasibility of variable camber foils

Abstract: A decade of research into electroactive polymer actuators is leading to the exploration of applications. These technologies are not ready to compete with the internal combustion engine and electric motors in high power propulsion systems but are suitable for intermittent or aperiodic applications with moderate cycle life requirements, providing an alternative to solenoids and direct drive electric motors. Polypyrrole, an emerging actuator material, is applied to drive hydrodynamic control surfaces and in particular to change the camber of a foil. The foil is intended for use in the propeller blade of an autonomous underwater vehicle. A scaled prototype is constructed which employs polypyrrole actuators imbedded within the blade itself to vary camber. The kinematics required to generate camber change are demonstrated, with >30/spl deg/ deflections of the trailing edge being observed from both bending bilayer and linear actuator designs. Forces developed in still conditions are five times lower than the 3.5 N estimated to be required to implement variable camber. The observed 70 kJ/m/sup 3/ polypyrrole work density however is more than sufficient to produce the desired actuation from within the limited blade volume, enabling an application that is not feasible using direct drive electric motors. A key challenge with the polypyrrole actuators is to increase force without sacrificing speed of actuation.

Use of a shape memory alloy for the design of an oscillatory propulsion system

Abstract: This study investigates the potential for incorporating the elastic mechanisms found in fish propulsive systems into mechanical systems for the development of underwater propulsion. Physical and kinematic information associated with the steady swimming of the bonito and other scombrid species was used for the design. Several electroactive materials were examined for simulating muscle behavior and their relative suitability was compared. A dynamic analysis method adapted for muscle, which is a work-loop technique, would provide valuable information. However, the lack of such information on engineering materials made any direct comparison between the biological and mechanical systems difficult. Based on available information, nickel-titanium shape memory alloy (SMA) was better suited to produce relatively slow and powerful steady swimming of scombrid species. The simplified geometry of muscular systems and axial tendons was adapted. These arrangements alleviate the limited strain of the SMA by trading force for distance and provide an effective force transmission pathways to the backbone.

Sensor Needs for Control and Health Management of Intelligent Aircraft Engines

Abstract: NASA and the U.S. Department of Defense are conducting programs which support the future vision of "intelligent" aircraft engines for enhancing the affordability, performance, operability, safety, and reliability of aircraft propulsion systems. Intelligent engines will have advanced control and health management capabilities enabling these engines to be self-diagnostic, self-prognostic, and adaptive to optimize performance based upon the current condition of the engine or the current mission of the vehicle. Sensors are a critical technology necessary to enable the intelligent engine vision as they are relied upon to accurately collect the data required for engine control and health management. This paper reviews the anticipated sensor requirements to support the future vision of intelligent engines from a control and health management perspective. Propulsion control and health management technologies are discussed in the broad areas of active component controls, propulsion health management and distributed controls. In each of these three areas individual technologies will be described, input parameters necessary for control feedback or health management will be discussed, and sensor performance specifications for measuring these parameters will be summarized.

High-aspect ratio hybrid airship

Abstract: In one aspect, a hybrid airship including an outer shell, a plurality of helium filled gas envelopes, and an all-electric propulsion system can have a high-aspect ratio wing shape. In some embodiments, the hybrid airship may be launched using buoyancy lift alone and aerodynamic lift may be provided by the all-electric propulsion system. In one aspect, a photovoltaic array and a high energy density power storage system may be combined to power the propulsion system making the propulsion system regenerative. The high-aspect ratio wing shape provides low drag, and can allow the hybrid airship to fly at an altitude of at least about 100,000 ft. By continuously recharging the power storage system, the hybrid airship in accordance with some embodiments can stay aloft for months or even years. The hybrid airship may function as a military intelligence, surveillance, and reconnaissance and communications relay platform.

Delta-winged hybrid airship

Abstract: In one aspect, a hybrid airship including an outer shell, a plurality of helium filled gas envelopes, and an all-electric propulsion system may have the shape of a delta-wing. In some embodiments, the hybrid airship may be launched using buoyancy lift alone and aerodynamic lift may be provided by the all-electric propulsion system. In one aspect, a photovoltaic array and a high energy density power storage system may be combined to power the propulsion system making the propulsion system regenerative. The delta-wing shape can provide a surface area large enough to accommodate very large circular or elliptical transmission devices. By continuously recharging the power storage system, the hybrid airship in accordance with some embodiments can stay aloft at an operational altitude of at least about 85,000 ft for months or even years. The hybrid airship may function as an airborne military communications relay platform.

On Control of Permanent-Magnet Synchronous Motors in Hybrid-Electric Vehicle Applications

Abstract: This thesis deals with design and analysis of the control system structure for electric drives equipped with permanent-magnet synchronous motors with a salient rotor. The intended application is propulsion in electric- and hybrid-electric vehicles. Particulary, sensorless control, meaning vector control without a mechanical rotor position sensor, is considered. A speed and position estimator of phase-locked loop type, previously reported in the literature, is analyzed with respect to the salient rotor and impact of parameter errors. Modifications are proposed to allow for operation in the whole speed range and the estimator's capacity to handle large speed estimation errors is improved. As a result of the analysis, simple parameter selection rules are derived, reducing the amount of trial-and-error work required in the design and tuning of the drive. A transient model taking harmonics into account is reviewed and its impact on current harmonics, when utilizing synchronous-frame PI current controllers, is investigated, both through simulations and experiments. Field-weakening operation is also considered. The closed-loop dynamics of a field-weakening controller, previously reported in the literature, is analyzed and verified experimentally, considering salient permanent-magnet synchronous motors. The theory considering loss minimization, by means of control, is reviewed and some analytical results are presented which can function as a useful tool when designing the control system of any electrical drive consisting of a permanent-magnet synchronous motor and corresponding inverter.

Optimization of thrust allocation in the propulsion system of an underwater vehicle

Abstract: The paper addresses methods of thrust distribution in a propulsion system for an unmanned underwater vehicle It concentrates on finding an optimal thrust allocation for desired values of forces and moments acting on the vehicle Special attention is paid to the unconstrained thrust allocation The proposed methods are developed using a configuration matrix describing the layout of thrusters in the propulsion system The paper includes algorithms of thrust distribution for both faultless work of the propulsion system and a failure of one of the thrusters Illustrative examples are provided to demonstrate the effectiveness and correctness of the proposed methods

Green propellant propulsion concepts for space transportation and technology development needs

Abstract: A study has been performed under contract from ESA/ESTEC identifying the development needs in Europe in the field of new green propellant utilization Criteria for green propellants are defined and discussed Promising propellants are identified together with their rating wrt those criteria, in particular establishing a measure of the toxicity Two application fields are considered: (1) high thrust, which aims at first and second stages of launchers; and (2) low thrust, which considers orbital propulsion of upper stages and future space vehicles like space planes Propulsion concepts are shown with their technological solutions The development needs wrt the existing technology status in Europe are identified and prioritised, and corresponding laboratory experiments are given

Shipboard regasification for lng carriers with alternate propulsion plants

Abstract: A liquefied natural gas carrier uses a diesel engine or gas turbine propulsion plant fitted with a shipboard regasification system. The propulsion plant can provide either a direct mechanical drive of the propeller shaft and propeller, or can be fitted with an integrated electric power plant using an electric motor or motors to drive the propeller shaft and propeller. The regasification system includes a heat input source of exhaust gas heat exchangers, electric water heaters and supplemental heaters to provide an additional heat source to a hot water circulating loop. The liquefied natural gas contacts the hot water or heating medium circulating loop and is regasified. An undersea conduit from the ship transmits the regasified natural gas to an on shore plant.

Source modelling of road vehicles

Abstract: The state-of-the-art of acoustic source modelling of road vehicles has been reviewed. Extensive measurements and simulations have been carried out. The aim has been to identify and quantify all relevant parameters influencing the noise emission of road vehicles. The collected information has been used to construct a source model suitable to combine with point-to-point sound propagation theory to calculate day-evening-night weighted yearly average sound pressure levels of road traffic noise. Each vehicle category is represented by two point sources, each having a specified sound power having contributions from tyre/road (rolling) noise and propulsion noise. As a minimum 3 vehicle categories are used: Passenger cars, medium heavy and heavy vehicles. Additional categories are defined. The medium heavy vehicle has two axles and the heavy vehicle has 3 or more axles but corrections are made for the number of axles. All default data refer to a reference condition: constant speed, 20 °C and the average of DAC 0/11 and SMA 0/11 road surfaces. Deviations from these conditions are corrected for. Default data, one constant and one speed coefficient, for rolling noise are given for each frequency band, 25-10000 Hz, using a logarithmic speed dependence. 80% of the rolling noise sound power is assigned a point source at 0,01 m and 20% is assigned a point source at 0,3 m (passenger cars) or 0,75 m (heavy vehicles). Default data, one constant and one speed coefficient, for propulsion noise are given for each frequency band, 25-10000 Hz, using a linear speed dependence. 20% of the propulsion noise sound power is assigned a point source at 0,01 m and 80% is assigned a point source at 0,3 m (passenger cars) or 0,75 m (heavy vehicles). Rolling noise is corrected for different road surfaces and different air temperatures. It is also possible to correct for wetness, studded tyres and number of axles of heavy vehicles. Propulsion noise is corrected for acceleration/deceleration. All point sources are assigned a specific frequency dependent vertical directivity with the main purpose to take the screening of the car body into account. The lowest point source is assigned a specific frequency dependent horizontal directivity with the main purpose to take the horn effect of the tyre/road source into account. The highest point source for propulsion noise and heavy vehicles is assigned a frequency independent horizontal directivity. Propagation effects are taken into account by giving different acoustic impedances of some different road surfaces.

Fault tolerance in multiphase propulsion motors

Abstract: This paper reviews the current state of marine electric propulsion motors, considers the benefits to be achieved by using a high phase number for excitation and considers the specific increased fault tolerance available through the use of a multiphase configuration. The multiphase work uses a generalised machine model of arbitrary phase number.

Time Simulations of the Response of Maneuvering Flexible Aircraft

Abstract: This work is concerned with time simulations of the response of flying flexible aircraft to initial conditions and external excitations, such as gusts. The simulations are based on a unified formulation of the problem of dynamics and control of maneuvering flexible aircraft developed recently by the authors. The formulation represents a seamless integration of pertinent material from the areas of analytical dynamics, structural dynamics, aerodynamics, and controls. It incorporates both the aircraft rigid-body motions and elastic deformations and it includes the aerodynamic, propulsion, gravity, and control forces, all in a rigorous manner. The formulation lends itself to efficient computer processing of the aircraft response. The formulation contains improvements over the earlier formulation by the authors in the form of a reduced-order structural model and newly designed, easier-to-implement controller and state observer. The corresponding time simulations are entirely new, and no similar results have been obtained by other investigators. The developments should help with the design of the new generation of unmanned aerial vehicles (UAVs) and in particular with the design of autonomous UAVs controlled by autopilots.