Propulsion

About: Propulsion is a research topic. Over the lifetime, 24977 publications have been published within this topic receiving 200311 citations.

Hybrid vehicle employing hybrid system

Abstract: In a hybrid electric vehicle (HEV) employing a hybrid system using both an internal combustion engine and a second motor/generator as a propelling power source for vehicle propulsion, and also employing a first generator driven by the engine for power generation, an integrated HEV control system is provided to control the engine, and the first and second motor/generators. The integrated HEV control system permits operation of only the second motor/generator as the propelling power source to establish a motor propelled vehicle driving mode and simultaneously basically inhibits operation of the engine, when satisfying at least a condition that the engine misfire occurs. If a power generation requirement or a battery recharge requirement is present during the misfire period, operation of the engine is temporarily permitted for driving the first motor/generator only for a battery recharge.

Design and Modeling Issues for Integrated Airframe/Propulsion Control of Hypersonic Flight Vehicles

Abstract: TraditionaLly the systems integration process in aerospace controls is to make individually desig subsystems work together, that is, to ensure functional compatibility and minimize adverse interactions. With large hypersonic vehicles the aerodynamic, propulsion, structural, and controls features are intrinsically highly interactive dynamically over a wide range of frequencies. Consequently, systems integration activities must be enormously expanded in scope and degree to assure a successful result. In essence the new goal of dynamic systems integration is to carry out concurrent multidisciplinary design of the highly interactive systems to maximize overall aircraft performance in its broadest terms. Cooperative consolidation and interaction of functions and subsystems to achieve performance levels and design synergism greater than would be possible with independent, individual subsystem designs are the natural consequences desired.

Mission Analysis and Aircraft Sizing of a Hybrid-Electric Regional Aircraft

Abstract: The purpose of this study was to explore advanced airframe and propulsion technologies for a small regional transport aircraft concept (approximately 50 passengers), with the goal of creating a conceptual design that delivers significant cost and performance advantages over current aircraft in that class. In turn, this could encourage airlines to open up new markets, reestablish service at smaller airports, and increase mobility and connectivity for all passengers. To meet these study goals, hybrid-electric propulsion was analyzed as the primary enabling technology. The advanced regional aircraft is analyzed with four levels of electrification, 0 percent electric with 100 percent conventional, 25 percent electric with 75 percent conventional, 50 percent electric with 50 percent conventional, and 75 percent electric with 25 percent conventional for comparison purposes. Engine models were developed to represent projected future turboprop engine performance with advanced technology and estimates of the engine weights and flowpath dimensions were developed. A low-order multi-disciplinary optimization (MDO) environment was created that could capture the unique features of parallel hybrid-electric aircraft. It is determined that at the size and range of the advanced turboprop: The battery specific energy must be 750 watt-hours per kilogram or greater for the total energy to be less than for a conventional aircraft. A hybrid vehicle would likely not be economically feasible with a battery specific energy of 500 or 750 watt-hours per kilogram based on the higher gross weight, operating empty weight, and energy costs compared to a conventional turboprop. The battery specific energy would need to reach 1000 watt-hours per kilogram by 2030 to make the electrification of its propulsion an economically feasible option. A shorter range and/or an altered propulsion-airframe integration could provide more favorable results.

Motors for Ship Propulsion

Abstract: Electric propulsion of ships has experienced steady expansion for several decades. Since the early 20th century, icebreakers have employed the flexibility and easy control of direct current (dc) motors to provide for ship operations that split ice with back and forth motion of the ship. More recently, cruise ships have employed diesel-electric propulsion systems to take advantage of the flexibility of diesel, as opposed to steam engines, and because the electric plant can also be used for hotel loads. Research vessels, ferries, tankers, and special purpose vessels have also taken advantage of increased flexibility and fuel efficiency with electric propulsion. Today, the U.S. Navy is building an “all electric” destroyer to be named “Zumwalt,” which employs two induction motors for propulsion. There are several different classes of motors that might be considered for use in ship propulsion, ranging from dc (commutator) motors through conventional induction and synchronous motors to permanent magnet synchronous machines, doubly fed machines and superconducting alternating current (ac) and acyclic homopolar machines. This review paper describes features of some of the major classes of motor that might be used in ship propulsion.