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Energy Recovery Rate from an Electric Air-cycle System under the Cruising Altitude and Speed.

IHI Corporation-Naoki Seki, Hitoshi Oyori
Akita University-Takahiro Adachi, Mikio Muraoka
  • Technical Paper
  • 2019-01-1905
To be published on 2019-09-16 by SAE International in United States
In this study, we focus on an electric air-cycle system in an electric aircraft, where the system has an electric compressor instead of a hydraulically-operated oil-based compressor. The electric compressor consumes the power to compress the rarefied air outside and take it in the system. The air goes through the air-cycle as a working fluid to exchange the heat and work. The main purpose of the air-cycle is to adjust the temperature and pressure in a cabin. Therefore, the working fluid of the air repeats compression and expansion. The working fluid passing through the cabin absorbs heat from the passengers and avionics. After that, the air is discharged outside with higher heat level and pressure levels. This means that the discharged air has a potential energy to recover the power consumption in the electric compressor. So, we have analytically estimated an energy recovery rate which is defined as a ratio of the potential energy of the discharged air to the energy consumption in the compressor, and shown the recovery rate under the condition of cruising…
 

Gradationally Controlled Voltage Inverter for More Electric Aircrafts

IHI Corporation-Hitoshi Oyori
Mitsubishi Electric Corp.-Tetsuya Kojima, Masahiro Sugahara, Yusuke Shirouchi, Hisatoshi Fukumoto, Akihiko Iwata
  • Technical Paper
  • 2019-01-1913
To be published on 2019-09-16 by SAE International in United States
Over recent decades, there has been a lot of progress toward a more electric aircraft (MEA) to reduce emissions and fuel consumption. In MEAs, many subsystems that previously used hydraulic or pneumatic power have been replaced by electrical systems with inverters and electrical machines. Therefore, MEAs reduce the weight, i.e. fuel consumption, and maintenance cost. To achieve advanced electrical systems, the weight of inverters has significant importance. In this work, a gradationally controlled voltage (GCV) inverter is proposed to reduce the weight and enhance reliability. A GCV inverter can supply gradational quasi-sinusoidal voltages combining two different voltages from a 3-phase 3-level (main) inverter and three single-phase H-bridge (sub) inverters. A dc power supply is required only for the main inverter. A main inverter with Si-IGBTs supplies the fundamental voltage by only one switching in the fundamental period. Consequently, the switching loss is minimized and hence the weight of cooling systems can be reduced. Sub inverters, which have the half of dc-link voltage of the main inverter, employ SiC-MOSFETs with higher switching frequency and compensate for…
 

Flight Optimization Model on Global and Interval Ranges for Conceptual Studies of MEA Systems

IHI Corporation-Hitoshi Oyori, Hirotaka Sugawara, Naoki Seki
Akita University-Yotsugi Shibuya
  • Technical Paper
  • 2019-01-1906
To be published on 2019-09-16 by SAE International in United States
In development of more electric aircraft applications, it is important to discuss aircraft energy management on various level of aircraft operation. This paper presents a computationally efficient optimization model for evaluating flight efficiency on global and interval flight ranges. The model is described as an optimal control problem with an objective functional subjected to state condition and control input constraints along a flight path range. A flight model consists of aircraft point-mass equations of motion including engine and aerodynamic models. The engine model generates the engine thrust and fuel consumption rate for operation condition and the aerodynamic model generates the drag force and lift force of an aircraft for flight conditions. These models is identified by data taken from a published literature as an example. First, approximate optimization process is performed for climb, cruise, decent and approach as each interval range path. Next, optimization for global range path involves whole flight path to find optimal operation condition in the flight. In aircraft energy management, fuel consumption converts into not only thrust power, but power of…
 

Electromagnetic Characteristic Comparison of Superconducting Synchronous Motors for Electric Aircraft Propulsion Systems

IHI Corporation-Hitoshi Oyori
The University of Tokyo-Yutaka Terao, Yusuke Ishida, Hiroyuki Ohsaki
  • Technical Paper
  • 2019-01-1912
To be published on 2019-09-16 by SAE International in United States
Aircraft service has been increasing today and it also results in the increase of the greenhouse gas emission. To solve this problem, the electric aircraft propulsion system is the key solutions to realize the clean and high efficiency aircraft, while demanding higher output density motors. So far, though 5 kW/kg is realized with permanent magnet type synchronous motors, the electric aircraft for over 100 passengers demands motors with 16 -20 kW/kg. Superconducting (S.C.) technology is one of the effective candidates for higher output density motors. In comparison with copper wires, the S.C. wires have higher current density at less than –200 ℃. And we can make a lighter weight coil with the S.C. wires. So far, many groups have been studying the S.C. motors over 16 kW/kg. Generally, there are two kinds of S.C motors. One is the S.C. motors made of the S.C. field coils and copper armature windings. The other is the fully S.C. motors using S.C. field and armature windings. We have been studying the fully S.C. motors with two kinds of…
 

Validation of Wireless Power Transfer up to 11kW Based on SAE J2954 with Bench and Vehicle Testing

IHI Corporation-Satoshi Yazaki
Argonne National Laboratory-Theodore Bohn
Published 2019-04-02 by SAE International in United States
Wireless Power Transfer (WPT) promises automated and highly efficient charging of electric and plug-in-hybrid vehicles. As commercial development proceeds forward, the technical challenges of efficiency, interoperability, interference and safety are a primary focus for this industry.The SAE Vehicle Wireless Power and Alignment Taskforce published the Recommended Practice J2954 to help harmonize the first phase of high-power WPT technology development. SAE J2954 uses a performance-based approach to standardizing WPT by specifying ground and vehicle assembly coils to be used in a test stand (per Z-class) to validate performance, interoperability and safety. The main goal of this SAE J2954 bench testing campaign was to prove interoperability between WPT systems utilizing different coil magnetic topologies. This type of testing had not been done before on such a scale with real automaker and supplier systems. Several automakers, suppliers and government employees worked together to create a test plan, perform the testing and analyze the results.To evaluate the interoperability, performance, and electromagnetic emissions of this technology, a bench test program was created, supported by the SAE J2954 WPT and Alignment…
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Reliability Case Analysis of an Autonomous Air Cooling System (AACS) for Aerospace Applications

IHI Corporation-Naoki Seki
University of Strathclyde-Chung Man Fong, Patrick Norman
Published 2018-10-30 by SAE International in United States
Current More Electric Aircraft (MEA) utilize Liquid Cooling Systems (LCS) for cooling on-board power electronics. In such LCS, coolant pipes around the structure of the aircraft are used to supply water glycol based coolant to sink heat from power electronics and other heat loads in the electronic bay. The extracted heat is then transferred to ram air through downstream heat exchangers.This paper presents a reliability examination of a proposed alternative Autonomous Air Cooling System (AACS) for a twin engine civil MEA case study. The proposed AACS utilizes cabin air as the coolant which is in turn supplied using the electric Environmental Control System (ECS) within the MEA. The AACS consists of electrical blowers allocated to each heat load which subsequently drive the outflow cabin air through the heat sinks of the power electronics for heat extraction. No additional heat exchanger is required after this stage in which the heated air is directly expelled overboard. One key advantage is the avoidance of liquid coolant leakage with the removal of liquid coolant from the MEA.It is necessary…
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Conceptual Study of Low-Pressure Spool-Generating Architecture for More Electric Aircraft

IHI Corporation-Noriko Morioka, Tsuyoshi Fukuda
IHI Aerospace Co. Ltd.-Hitoshi Oyori
Published 2015-09-15 by SAE International in United States
This paper will propose a novel power generating system concept including an auxiliary, backup and emergency power source. Existing aircraft employ an auxiliary power unit (APU) and a ram air turbine (RAT) for power generation besides aero-engine generators. An APU works prior to starting propulsion on the ground and as a backup power plant during flight. The RAT is activated due to the need to maintain the essential systems in the case of an emergency situation. Both systems are optimized on conventional aircraft in which hydraulic, pneumatic and electric systems are supplied for control and equipment.Although a conventional aircraft needs hydro pumps and air compressors, the coming of a new era of more-electric architecture for aircraft and propulsion will be the stimulus to improve aircraft systems [1]. In more-electric aircraft, the authors focus on the low-pressure spool generation system of aero-engines. This system is anticipated for large power sources that supply electricity to a bleed-less system, though the high-pressure spool-generating capability is restricted because of the mechanical integrity of the power off-take and aero-engine control…
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A Study of Air/Fuel Integrated Thermal Management System

IHI Corporation-Naoki Seki, Noriko Morioka
IHI Aerospace Co. Ltd.-Hitoshi Oyori
Published 2015-09-15 by SAE International in United States
This paper describes the concept of an air/fuel integrated thermal management system, which employs the VCS (Vapor Cycle System) for the refrigeration unit of the ECS (Environment Control System), while exchanging the heat between the VCS refrigerant and the fuel into the engine, and presents a feasibility study to apply the concept to the future all electric aircraft systems.The heat generated in an aircraft is transferred to the ECS heat exchanger by the recirculation of air and exhausted into the ram air. While some aircraft employ the fluid heat transfer loop, the transferred heat is exhausted into the ram air. The usage of ram air for the cooling will increase the ram drag and the fuel consumption, thus, less usage of ram air is preferable. Another source for heat rejection is the fuel. The heat exchange with the fuel does not worsen the fuel consumption, thus, the fuel is a preferable source. However, the heat exchange between hot air and fuel has a potential fire risk, so it would be difficult to apply the air/fuel…
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Aircraft Secondary Power System Integration into Conceptual Design and Its Application to More Electric System

IHI Corporation-Noriko Morioka
IHI Aerospace Co. Ltd.-Hitoshi Oyori
Published 2014-09-16 by SAE International in United States
Aircraft designers determine the optimum aircraft configuration to meet performance requirements. Aircraft secondary power systems are very important for aircraft operation, however, traditionally these systems have not been considered in detail while the aircraft configuration and specifications are preliminary studied. Therefore, we constructed an aircraft conceptual design tool considering the many aircraft systems. Furthermore, we applied this design tool to a simple design problem taking into account two different kinds of secondary power system architectures (i.e. the conventional bleed air system and the more electric system), and discussed how the introduction of new aircraft systems affects results. Although the present method is theoretical and conceptual with limited applicability, the effect of the aircraft's secondary power system upon the concerning aircraft specifications was made clear both for the bleed air system and the more electric system.
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Thermal Management System Concept with an Autonomous Air-Cooled System

IHI Corporation-Noriko Morioka
IHI Aerospace Co., Ltd.-Hitoshi Oyori
Published 2014-09-16 by SAE International in United States
Electrical power management is a key technology in the AEA (All-Electric Aircraft) system, which manages the supply and demand of the electrical power in the entire aircraft system. However, the AEA system requires more than electrical power management alone. Adequate thermal management is also required, because the heat generated by aircraft systems and components increases with progressive system electrification, despite limited heat-sink capability in the aircraft. Since heat dissipation from power electronics such as electric motors, motor controllers and rectifiers, which are widely introduced into the AEA, becomes a key issue, an efficient cooling system architecture should be considered along with the AEA system concept.The more-electric architecture for the aircraft has been developed; mainly targeting reduced fuel burn and CO2 emissions from the aircraft, as well as leveraging ease of maintenance with electric/electronic components. The AEA should pursue more efficient and eco-friendlier systems, which are easier to maintain than those of conventional aircraft/MEA (More-Electric Aircraft), to enhance benefits for passengers and operators. Given the crucial role of thermal management to construct the AEA, in this…
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