Fuel savings by optimal aircraft cruise with singular and chattering control

Author(s):  
Gottfried Sachs ◽  
Klaus Lesch
Keyword(s):  
2007 ◽  
Vol 35 (2) ◽  
pp. 70-93
Author(s):  
Marion G. Pottinger ◽  
Joseph D. Walter ◽  
John D. Eagleburger

Abstract The Congress of the United States petitioned the Transportation Research Board of the National Academy of Sciences to study replacement passenger car tire rolling resistance in 2005 with funding from the National Highway Traffic Safety Administration. The study was initiated to assess the potential for reduction in replacement tire rolling resistance to yield fuel savings. The time required to realize these savings is less than the time required for automotive and light truck fleet replacement. Congress recognized that other factors besides fuel savings had to be considered if the committee’s advice was to be a reasonable guide for public policy. Therefore, the study simultaneously considered the effect of potential rolling resistance reductions in replacement tires on fuel consumption, wear life, scrap tire generation, traffic safety, and consumer spending for tires and fuel. This paper summarizes the committee’s report issued in 2006. The authors, who were members of the multidisciplinary committee, also provide comments regarding technical difficulties encountered in the committee’s work and ideas for alleviating these difficulties in further studies of this kind. The authors’ comments are clearly differentiated so that these comments will not be confused with findings, conclusions, and recommendations developed by the committee and contained in its final report.


Author(s):  
Charbel R Ghanem ◽  
Elio N Gereige ◽  
Wissam S Bou Nader ◽  
Charbel J Mansour

There have been many studies conducted to replace the conventional internal combustion engine (ICE) with a more efficient engine, due to increasing regulations over vehicles’ emissions. Throughout the years, several external combustion engines were considered as alternatives to these traditional ICEs for their intrinsic benefits, among which are Stirling machines. These were formerly utilized in conventional powertrains; however, they were not implemented in hybrid vehicles. The purpose of this study is to investigate the possibility of implementing a Stirling engine in a series hybrid electric vehicle (SHEV) to substitute the ICE. Exergy analysis was conducted on a mathematical model, which was developed based on a real simple Stirling, to pinpoint the room for improvements. Then, based on this analysis, other configurations were retrieved to reduce exergy losses. Consequently, a Stirling-SHEV was modeled, to be integrated as auxiliary power unit (APU). Hereafter, through an exergo-technological detailed selection, the best configuration was found to be the Regenerative Reheat two stages serial Stirling (RRe-n2-S), offering the best efficiency and power combination. Then, this configuration was compared with the Regenerative Stirling (R-S) and the ICE in terms of fuel consumption, in the developed SHEV on the WLTC. This was performed using an Energy Management Strategy (EMS) consisting of a bi-level optimization technique, combining the Non-dominated Sorting Genetic Algorithm (NSGA) with the Dynamic Programming (DP). This arrangement is used to diminish the fuel consumption, while considering the reduction of the APU’s ON/OFF switching times, avoiding technical issues. Results prioritized the RRe-n2-S presenting 12.1% fuel savings compared to the ICE and 14.1% savings compared to the R-S.


2021 ◽  
Vol 13 (4) ◽  
pp. 1880
Author(s):  
Todd Chou ◽  
Vasileios Kosmas ◽  
Michele Acciaro ◽  
Katharina Renken

Wind-assisted ship propulsion (WASP) technology seems to be a promising solution toward accelerating the shipping industry’s decarbonization efforts as it uses wind to replace part of the propulsive power generated from fossil fuels. This article discusses the status quo of the WASP technological growth within the maritime transport sector by means of a secondary data review analysis, presents the potential fuel-saving implications, and identifies key factors that shape the operational efficiency of the technology. The analysis reveals three key considerations. Firstly, despite the existing limited number of WASP installations, there is a promising trend of diffusion of the technology within the industry. Secondly, companies can achieve fuel savings, which vary depending on the technology installed. Thirdly, these bunker savings are influenced by environmental, on-board, and commercial factors, which presents both opportunities and challenges to decision makers.


MTZ worldwide ◽  
2013 ◽  
Vol 74 (11) ◽  
pp. 18-23 ◽  
Author(s):  
Karl Krebber-Hortmann ◽  
Andreas Köster ◽  
Andres Tönnesmann ◽  
Costantino Brunetti
Keyword(s):  

2021 ◽  
Author(s):  
Evan Pelletier ◽  
Wushuang Bai ◽  
Miguel Alvarez Tiburcio ◽  
John Borek ◽  
Stephen Boyle ◽  
...  

2021 ◽  
pp. 1-45
Author(s):  
Benjamin Leard ◽  
Joshua Linn ◽  
Yichen Christy Zhou

Abstract During historical periods in which US fuel economy standards were unchanging, automakers increased performance but not fuel economy, contrasting with recent periods of tightening standards and rising fuel economy. This paper evaluates the welfare consequences of automakers forgoing performance increases to raise fuel economy as standards have tightened since 2012. Using a unique data set and a novel approach to account for fuel economy and performance endogeneity, we find undervaluation of fuel cost savings and high valuation of performance. Welfare costs of forgone performance approximately equal expected fuel savings benefits, suggesting approximately zero net private consumer benefit from tightened standards.


Author(s):  
C. F. McDonald

Because of intense development in the aircraft gas turbine field over the last 30 years, the fixed boundary recuperator has received much less development attention than the turbomachinery, and is still proving to be the nemesis of the small gas turbine design engineer. For operation on cheap fuel, such as natural gas, the simple cycle-engine is the obvious choice, but where more expensive liquid fuels are to be burned, the economics of gas turbine operation can be substantially improved by incorporating an efficient, reliable recuperator. For many industrial, vehicular, marine, and utility applications it can be shown that the gas turbine is a more attractive prime mover than either the diesel engine or steam turbine. For some military applications the fuel logistics situation shows the recuperative gas turbine to be the most effective power plant. For small nuclear Brayton cycle space power systems the recuperator is an essential component for high overall plant efficiency, and hence reduced thermal rejection to the environment. Data are presented to show that utilization of compact efficient heat transfer surfaces developed primarily for aerospace heat exchangers, can result in a substantial reduction in weight and volume, for industrial, vehicular, marine, and nuclear gas turbine recuperators. With the increase in overall efficiency of the recuperative cycle (depending on the level of thermal effectiveness, and the size and type of plant), the cost of the heat exchanger can often be paid for in fuel savings, after only a few hundred hours of operation. Heat exchanger surface geometries and fabrication techniques, together with specific recuperator sizes for different applications, are presented. Design, performance, structural, manufacturing, and economic aspects of compact heat exchanger technology, as applied to the gas turbine, are discussed in detail, together with projected future trends in this field.


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