Engine Cost Research Articles

Robust Gas Turbine and Airframe System Design in Light of Uncertain Fuel and Prices

This paper presents a study that numerically investigated which cruise speed the next generation of short-haul aircraft with 150 seats should fly at, and whether a conventional two- or three-shaft turbofan, a geared turbofan, a turboprop, or an open rotor should be employed to make the aircraft’s direct operating cost robust to uncertain fuel and carbon () prices in the year 2030, taking the aircraft productivity, the passenger value of time, and the modal shift into account. To answer this question, an optimization loop was set up in MATLAB consisting of nine modules covering gas turbine and airframe design and performance, flight and aircraft-fleet simulation, operating cost, and optimization. If the passenger value of time is included, the most robust aircraft design is powered by geared turbofan engines and cruises at Mach 0.80. If the value of time is ignored, however, then a turboprop aircraft flying at Mach 0.70 is the optimum solution. This demonstrates that the most fuel-efficient option, the open rotor, is not automatically the most cost-efficient solution because of the relatively high engine and airframe costs.

Modifications to Improve Fuel Consumption in the Remanufacture of Spark-Ignition Engines for Electric Generators

This paper describes the development of a water-cooled, lean burn, gaseous fueled engine designed for distributed power installations. Electric generators have become popular because they provide a portable supply of electrical power at consumer demand. They are used in critical need areas such as hospitals and airports, and have found their way into homes frequented with power outages or homes in remote locations. Gensets are available in a wide variety of sizes ranging from 1 kilowatt (kW) to thousands of kilowatts. In the midrange, the power sources are typically spark-ignition, automotive type internal combustion engines. Since engines designed for automotive use are subject to different emission regulations, and are optimized for operation at revolutions per minute (RPM) and brake mean effective pressures (BMEPs) above that of electric generator engines, modifications can be made to optimize them for gensets. This work describes modifications which can be made during remanufacturing an automotive engine to optimize it for use as a generator engine. While the work recognizes the potential for cost savings from the use of remanufactured automotive engines over that of using new automotive engines and the majority of the design constraints were adopted to reduce engine cost, the main focus of the work is quantifying the increase in fuel efficiency that can be achieved while meeting the required EPA emission requirements. This paper describes the seven combustion chamber designs that were developed and tested during this work. Friction reduction was obtained in both valve train and journal bearing design. The engine optimized for fuel efficiency produced a maximum brake thermal efficiency (BTE) of 37.5% with λ = 1.63. This yielded an EPA test cycle average brake specific fuel consumption (BSFC) of 325 g/kW hr. Modification of the spark advance and low load equivalence ratio to meet EPA Phase III emission standards resulted in an EPA test cycle average BSFC of 330 g/kW hr. When the engine used in this research was tested in its unmodified, automotive configuration under the EPA compliant test cycle, its EPA test cycle average BSFC was 443.4 g/kW hr. This is a 34% increase in fuel consumption compared to the modified engine.

Convex Modeling and Sizing of Electrically Supercharged Internal Combustion Engine Powertrain

This paper investigates a concept of an electrically supercharged internal combustion engine (ICE) powertrain. A supercharger consists of an electric motor and a compressor. It draws its power from an electric energy buffer (e.g., a battery) and helps the engine during short-duration high-power demands. Both the engine and the buffer are sized to reduce the sum of the vehicle operational (fuel) and component (engine and buffer) costs. For this purpose, a convex driving cycle-based vehicle model is derived, enabling the formulation of an underlying optimization problem as a second-order cone program (SOCP). Such a program can be efficiently solved using dedicated numerical tools (for a given gear selection strategy), which provides not only the optimal engine/buffer sizes but optimal vehicle control and state trajectories (e.g., compressor power and buffer energy) as well. Finally, the results obtained from a representative numerical case study are discussed in detail.

The improvement of friction bearing manufacturing technology by using copper alloy

The research objective is to increase the operational life of friction bearings by technological methods, particularly, in relation to kinematic mechanisms used for conversion of motion in the tractor-type internal combustion engines. The research object is the process of friction and wear in friction bearings. Theoretical regularities related to change in friction and wear parameters in the bearings were used, depending on the used materials and load conditions. The studies were conducted by the selection of variants of friction pairs for friction bearings used in kinematic mechanisms of internal combustion engines operating at high radial loads and under rapidly changing load modes. In the course of this study, the authors selected the best design and technological characteristics for bearings with certain pairs of friction and studied the friction and wear regularities of the selected pairs of friction bearings. The study also implied the analysis of the initial data for the evaluation of wear resistance of the selected pairs of friction bearings and the development of technical specifications for their use in internal combustion engines. The use of copper for manufacturing the bearing shell was determined as one of the promising ways to increasing their quality indicators. Highly effective properties of copper for manufacturing the supporting elements of plain bearings were experimentally confirmed. The operational life of bearings can reach 14,000 motor-hours, which exceeds the operational life of a standard serial bearing shell by more than eight times. The economic result of applying the copper inserts implies the fact that given an increase in engine cost approximately by 2 %, repair costs per 1 h of the engine run are reduced by more than eight times. Design features of the proposed shells differ from the standard ones only by material; their dimensions and configuration are completely analogous to the standard inserts that allow using the new type of inserts for all currently used engine models. The most significant theoretical result of this study is the obtained functional connection of the friction and wear performance, expressed as a thermal stability coefficient, which gives the possibility to justify the choice of materials for the kinematic mechanisms of motion conversion in the tractor-type internal combustion engines based on studying thermal properties, characteristics of the materials employed, and the expected operating conditions. Industrial implementation of research results will give the economic effect—application of the developed bearings results in repair cost reduction by more than eight times.

Impact of Emerging Engine and After-Treatment Technologies for Improved Fuel Efficiency and Emission Reduction for the Future Rail Diesel Engines

The future stringent emission limits and fuel-saving requirements for non-road engines, in particular for the rail sector, require further research investments both on engine and after-treatment technologies. Therefore, the aim of this study is to identify, mainly on a literature data base, the most promising emerging engine technologies (waste heat recovery, turbocharging, etc.) and exhaust after-treatment systems (de-NO x catalyst systems, particulate filters, etc.) for improved fuel efficiency and emissions reduction of rail diesel engines. The considered technologies are currently from production series or under development mostly in the on-road research domain. The approach taken has been to gather available information and data from research and industry sources for the most promising emerging technologies of on-road heavy-duty (HD) engines. The collected data have been properly analyzed and elaborated in order to identify the most transferable data from road to the rail sector. The study is one of the results of a project carried out within the 7th European Framework program in which several academic and industrial partners have participated. Engine side and exhaust after-treatment system side technologies are discussed separately. The former takes into account quantitative data from the literature survey, mainly in terms of fuel efficiency benefits, and summarizes the evaluation in a return on investment calculation on the base of a reference rail engine cost. In the latter, essentially qualitative information has been collected. The analysis has been carried out by means of spider diagrams that are used to show the potential of the grouped after-treatment technologies in terms of pollutant emission reduction, size/weight reduction, technology maturity, and cost reduction. The results indicate that the emerging engine technologies are mostly about engine efficiency improvements, of which waste heat recovery shows the greatest potential in terms of fuel efficiency improvement. On the after-treatment system side, the integration of multiple after-treatment functionalities into a single device is particularly attractive for rail applications because it could significantly decrease space and weight requirements, as could the use of alternative to urea media for ammonia storage in the case of selective catalytic reduction (SCR) system functionalities.

Determination of the ejector dimensions of a bus air-conditioning system using analytical and numerical methods

Comfortable journey with commercial buses is an essential goal of transportation companies. An air-conditioning system can play an important role for this comfortable journey but it can put extra load on the engine and extra cost in the fuel consumption. The purpose of this work is to increase the performance of air-conditioning system of the buses by reducing the load on the engine and fuel consumption. Using a two-phase ejector as an expansion valve can increase the coefficient of performance (COP) of the air-conditioning system. An improvement in the COP can reduce the empty vehicle weight and fuel consumption of buses. Two-phase ejector dimensions can be determined using the empirical methods available in the literature. In this paper, the two-phase ejector dimensions of air conditioning system for a bus are calculated using the analytical and numerical methods. First of all, the thermodynamic analysis of the vapor-compression refrigeration cycle with a two-phase ejector is performed, and then the ejector dimensions are subsequently determined. The cooling loads of the midibus and bus with R134a as a refrigerant are assumed to be 14 kW and 32 kW, respectively. The total length of the two-phase ejector for the midibuses and buses due to these cooling loads, are computed to be 480.8 mm and 793.1 mm, respectively. Also, an experimental setup is installed on a midibus air conditioner to turn it into the ejector air conditioning system to validate theoretical results with the experimental study.

G0710506 Hybrid Electric Vehicleシミュレータを用いた振動低減化制御の実験的検証([G071-05]エンジンシステム部門一般セッション(5):「エンジンの計測と制御」)

This study aims, for hybrid electric vehicle, to develop a controller for reducing torque ripple caused by fuel combustion in the combustion engine and reaction torque from road surface. Road surface reaction force and load torque are not measurable directly because the corresponding sensors cannot be easily attached due to lack of space for attaching in the engine structure, cost and fault diagnosis system of the sensors. Moreover HEV system is nonlinear. Therefore control system for reducing torque ripple should be designed under the assumptions where road surface reaction force and torque load are supposed to be unknown, and HEV system is nonlinear. In this paper, a control method for reducing the torque ripple by controlling the HEV assist motor is proposed. This control method required the only measurable crank angle. The effectiveness of the control method is verified experimentally by implementing the control law in a HEV physical simulator. HEV physical simulator consists of a power train, an engine alternative motor and a slider crank. As a result, the torque ripple is reduced by 33 percent.

A comprehensive literature review of bio-fuel performance in internal combustion engine and relevant costs involvement

Bio-fuel has come under consideration due to the effect of fossil oil crisis. Bio-fuels are acting as a renewable replacement of petroleum fuels due to some environmental and economic benefits. Bio-fuel can be produced from different kinds of raw materials. Researchers have seen that absolute utilization of bio-fuel is not appreciable as it will affect the food chain but the blend of bio-fuel with conventional fuel could precisely reduce its use and become beneficial to green house effect. It has been inferred that in the hot and cold environment bio-fuel is not fully convenient to replace fossil fuel. In the controlled environment with modified combustion equipment, biodiesel can be used as an alternate fuel. Research results reveal that bio-fuel has lower heating value in comparison to diesel fuel so it is consumed more in fuel-break mean effective power ratio and emits more NOx in comparison to the diesel fuel. Thus there remains a compromise between GHG emission and saving of fossil fuel energy by introducing bio-fuel either totally or as a blending component of engine fuel. Finally, bio-fuel could be considered as a replenishable energy source which might pave the future pathway management and planning of energy.

Toward the Expansion of Low-Pressure-Turbine Airfoil Design Space

Future engine requirements, including high-altitude flight of unmanned air vehicles as well as an impetus to reduce engine cost and weight, are challenging the current state of the art in low-pressure-turbine airfoil design. These new requirements present low-Reynolds number challenges as well as the need for high-performance, high-lift design concepts. Here, we report on an effort to expand the relatively well established aerodynamic design space for low-pressure turbine airfoils through the application of recent developments in transition modeling to airfoil design. Analytical and experimental midspan performance data and predicted loadings are presented for four high-lift airfoil designs based on the Pack B velocity triangles. The new designs represent a systematic expansion of low-pressure turbine airfoil design space through the application of high-lift design concepts for front- and aft-loaded airfoils. All four designs performed as predicted across a range of operationally representative Reynolds numbers. Full-span loss data for the new high-lift designs reveal increased endwall losses, which, with the application of nonaxisymmetric endwall contouring, have been substantially reduced. Taken holistically, the results presented here demonstrate that accurate transition modeling provides a reliable method to develop optimized, very high-lift airfoil designs. However, further improvements in endwall-loss mitigation technologies are required to enable the implementation of the very high-lift technology presented here in engine systems.

Investigation of main particulars subject to minimum building cost for chemical tankers

The maritime transportation sector is rapidly growing depending on the global growth, hence chemical tanker shipping is positively being affected concordantly. Detailed analyses are required to define costs accurately at the preliminary design stage as shipbuilding projects require high levels of financing which may be affected by daily price fluctuations in the global economic system.In this study, empirical formulas are derived in order to estimate the principal particulars, main engine power, weight components and costs of the chemical tankers less than 30,000DWT in the preliminary design stage. Utilizing the formulas that are derived from the data of recently built vessels; an approach based on systematic analysis method is presented to determine the principle particulars of the optimum vessel subject to minimum building costs of chemical tankers, which have different speeds and tonnages. In this study, three applications for the estimation of preliminary design parameters and investigation of optimum particulars are carried out. Consequently, it is shown that the preliminary design parameters can be estimated with fairly low errors and initial building costs can be decreased by up to 9% by optimizing the main particulars.

Efficiency of Gas Turbine Engines for Drive of Mechanisms for In-House Needs of Thermal Power Plants1,2

An equation is derived for determining the economic suitability, based on the period of return, of replacing an electrical drive mechanism for the in-house needs of a thermal power plant with a gas turbine engine as a function of the cost of electrical energy and fuel and the cost and performance of gas turbine engines.

The Application of a Wave Action Design Technique with Minimal Cost on a Turbocharged Engine Equipped with Water Cooled Charge Air Cooler Aimed for Energy Management

The vast majority of today's cars remain powered by gasoline or Diesel engines. In the European market, Diesel cars accounts for 55% of all new registrations while gasoline cars for 44%. All the other technologies such as hybrids, fully electric or natural gas and ethanol powered cars combine to make up the remaining 1%. Despite the publicity on these highly anticipated alternative technologies, statistics indicate that their usage remains marginal when compared to more ‘traditional’ powertrains. The internal combustion engine remains the principal way of transportation, at least for the foreseeable years. That being said, undesirable emissions (HC, CO, NOx, PM) are today's major concern because of their negative impact on air quality and global warming. The latest Euro 6 standard limits the CO emissions on a gasoline engine to 68% and the PM (particulate matter) on a Diesel engine to 96% lower than those established in 1992. CO2 emissions which are directly proportional to consumption rates are recently added to the list with a target of 95g/Km for 2020.The main trend for solving these issues is through engine downsizing with high rates of turbocharging accompanied by fuel injection control, after-treatment and system integration. Techniques that increment the energy saving costs. The ICCT (International Council on Clean Transportation) estimates that the cost of taking a 4-cylinder 1.5L Diesel engine from no emission controls to the Euro 6 standard is around US$1400. A major technique to gain control of the engine processes and achieve high performance and low emission levels is through air handling depicted by air intake tuning, turbocharging tuning and charge air cooling.This article briefly describes the air intake line of 4-cylinder 1.5L turbocharged Diesel engine and investigates the role of wave action phenomena on its intake line. The goal here is to achieve lower consumption and better performance by finding the optimal intake geometry. The latter comprises of a compressor wheel, a water cooled charge air cooler prototype (WCAC) and connecting pipes. The wave action effects were first explained and highlighted on a dynamic flow bench at “Mann+Hummel” using a frequency modeling approach which enabled to find the optimal length of piping upstream and downstream of the WCAC. Next this length was experimentally verified by mounting the different length on an engine test bench and registering pressure wave amplitudes. Finally the pressure recordings were fed to engine simulation software GT-PowerTM for a transient low speed simulation mimicking urban driving conditions and specific fuel consumption data were recovered.The result is a proposed air intake line for a turbocharged engine with a water cooled charge air cooler design choice. The proposed changes do not add any engine costs, but invests in significant R&D and retooling.

Performance and cost results from a DOE Micro-CHP demonstration facility at Mississippi State University

Cooling, Heating, and Power (CHP) systems have been around for decades, but systems that utilize 20kW or less, designated as Micro-CHP, are relatively new. A demonstration site has been constructed at Mississippi State University (MSU) to show the advantages of these micro scale systems. This study is designed to evaluate the performance of a Micro-CHP system as opposed to a conventional high-efficiency Heating, Ventilation, and Air Conditioning (HVAC) system that utilizes electrical power from the existing power grid. Raw data was collected for 7months to present the following results. The combined cycle efficiency from the demonstration site was averaged at 29%. The average combined boiler and engine cost was $1.8h−1 of operation for heating season and $3.9h−1 of operation for cooling season. The cooling technology used, an absorption chiller exhibited an average Coefficient of Performance (COP) of 0.27. The conventional high-efficiency system, during cooling season, had a COP of 4.7 with a combined cooling and building cost of $0.2h−1 of operation. During heating mode, the conventional system had an efficiency of 47% with a fuel and building electrical cost of $0.28h−1 of operation.

Microcode Compression Using Structured-Constrained Clustering

Modern microprocessors have used microcode as a way to implement legacy (rarely used) instructions, add new ISA features and enable patches to an existing design. As more features are added to processors (e.g. protection and virtualization), area and power costs associated with the microcode memory increased significantly. A recent Intel internal design targeted at low power and small footprint has estimated the costs of the microcode ROM to approach 20% of the total die area (and associated power consumption). Moreover, with the adoption of multicore architectures, the impact of microcode memory size on the chip area has become relevant, forcing industry to revisit the microcode size problem. A solution to address this problem is to store the microcode in a compressed form and decompress it at runtime. This paper describes techniques for microcode compression that achieve significant area and power savings, while proposes a streamlined architecture that enables high throughput within the constraints of a high performance CPU. The paper presents results for microcode compression on several commercial CPU designs which demonstrates compression ratios ranging from 50 to 62%. In addition, it proposes techniques that enable the reuse of (pre-validated) hardware building blocks that can considerably reduce the cost and design time of the microcode decompression engine in real-world designs.

Cost Analysis of Battery-powered Electric Vehicles in Macau

The development of electric vehicles (EVs) has advanced rapidly over the past decades. Researchers and engineers have concentrated on the improvement of EV performance through the advances in batteries, motors, converters, controllers and relevant auxiliaries, with great successes. Now, it comes to the stage of commercialization. It is important to understand various cost issues and the business models relating to EV application. This paper aims to discuss the life cycle cost (LCC) of both EV and internal combustion engine (ICE) vehicles in Macau. Viability of EVs will be assessed by comparing the LCCs of a Mitsubishi i-MiEV, and its comparable ICE counterpart “i”; the fuel cost and CO2 emission reduction of an EV will also be evaluated.

Experimental Research on the Performance of High-Speed Diesel Engine Fuelled with Emulsified Fuel Blend of HFO & Light Diesel

Using Heavy Fuel Oil (HFO) is a practical measure to reduce running cost of high-speed diesel engines. Extending application of HFO would be great helpful to mitigate nation wide energy shortage problem. The authors attempted a set of experiments with a view to demonstrating the performance of a high-speed diesel engine fuelled with fuel blend of HFO and Light diesel (HFO-L) and water emulsified HFO-L. A number of experiments on test bench were carried out to check power performance, fuel economy and combustion performance of the engine. The results indicate that it is practicable to use HFO-L fuel blend on high-speed diesel engine without many additional modifications on engine structure. Compared with HFO-L, water emulsified HFO-L has better combustion performance, and thus better fuel economy as well as low harmful emissions. In addition, compared with using light diesel fuel, when using emulsified HFO-L blend, the engine can be operated with the same power performance, but with higher the brake specific fuel consumption. Whereas, considering much lower price of heavy fuel oil, the fuel economy is greatly improved.

Multi-Objective Aerodynamic Optimization of Axial Turbine Blades Using a Novel Multilevel Genetic Algorithm

In this paper, a new multiploid genetic optimization method handling surrogate models of the CFD solutions is presented and applied for a multi-objective turbine blade aerodynamic optimization problem. A fast, efficient, robust, and automated design method is developed to aerodynamically optimize 3D gas turbine blades. The design objectives are selected as maximizing the adiabatic efficiency and torque so as to reduce the weight, size, and cost of the gas turbine engine. A 3D steady Reynolds averaged Navier–Stokes solver is coupled with an automated unstructured grid generation tool. The solver is verified using two well-known test cases. The blade geometry is modeled by 36 design variables plus the number of blade variables in a row. Fine and coarse grid solutions are respected as high- and low-fidelity models, respectively. One of the test cases is selected as the baseline and is modified by the design process. It was found that the multiploid multi-objective genetic algorithm successfully accelerates the optimization and prevents the convergence with local optimums.

Plug-in hybrid fuel cell vehicles market penetration scenarios

The main objective of this research is to analyze the impact of the market share increase of hydrogen based road vehicles in terms of energy consumption and CO 2, on today's Portuguese light-duty fleet. Actual yearly values of energy consumption and emissions were estimated using COPERT software: 167112 TJ of fossil fuel energy, 12213 kton of CO 2 emission and 141 kton of CO, 20 kton of HC, 46 kton of NO x and 3 kton of PM. These values represent 20–40% of countries total emissions. Additionally to base fleet, three scenarios of introduction of 10–30% fuel cell vehicles including plug-in hybrids configurations were analysed. Considering the scenarios of increasing hydrogen based vehicles penetration, up to 10% life cycle energy consumption reduction can be obtained if hydrogen from centralized natural gas reforming is considered. Full life cycle CO 2 emissions can also be reduced up to 20% in these scenarios, while local pollutants reach up to 85% reductions. For the purpose of estimating road vehicle technologies energy consumption and CO 2 emissions in a full life cycle perspective, fuel cell, conventional full hybrids and hybrid plug-in technologies were considered with diesel, gasoline, hydrogen and biofuel blends. Energy consumption values were estimated in a real road driving cycle and with ADVISOR software. Materials cradle-to-grave life cycle was estimated using GREET database adapted to Europe electric mix. The main conclusions on CO 2 full life cycle analysis is that light-duty vehicles using fuel cell propulsion technology are highly dependent on hydrogen production pathway. The worst scenario for the current Portuguese and European electric mix is hydrogen produced from on-site electrolysis (in the refuelling stations). In this case full life cycle CO 2 is 270 g/km against 190 g/km for conventional Diesel vehicle, for a typical 150,000 km useful life. A brief energy price analysis was presented. We conclude that hydrogen price equivalent to gasoline energy price (€/MJ) is important to the consumer preference of hydrogen based vehicles. It is also possible a fuel cell cost comparable with internal combustion engine cost if sufficient market penetration and power density increase are attained.

Optimization of System Parameters for Liquid Rocket Engines with Gas-Generator Cycles

System design of liquid rocket engines must consider engine performance, weight, cost, and reliability requirements. A general design optimization framework has been developed in this paper to select the best system parameters for liquid rocket engines with gas-generator cycles. The object is to maximize the specific impulse and vacuum thrust-to-weight ratio of the engine with given system requirements and design assumptions by changing thrust-chamber pressure and mixture ratio. The system analysis, along with the engine weight estimation, is based on a modular scheme. Multidisciplinary design optimization formulations including multidisciplinary feasible and collaborative optimization are used, evaluated, and compared during the optimization process. Several techniques of multi-objective processing are also used to identify the Pareto frontier and the optimal compromise solutions. A proposed cryogenic-propellant engine using liquid oxygen and hydrogen with a gas-generator cycle is studied as a specific example. Moreover, uncertainties in the engine operation, such as thrust-chamber pressure and mixture ratio, are taken into account as random variables in the reliability-based optimization. Results are presented to illustrate the tradeoff between the engine performance and reliability requirements.

4.1.1 A Case Study of the Effects of Platform Software Selection on Information System Maintenance Cost ‐ An Example of Enterprise Search System Establishment ‐

AbstractEnterprise search systems have been focused on since around 2005. However, there are very few case‐study reports/papers how to build enterprise search systems and how to provide their superior cost performance. We propose an importance of maintenance cost for system management, especially after system launch. Search engines, well known as Internet search, are generally employed as middleware of enterprise search systems. We tried an experimental study of estimating the system maintenance cost, in order to validate our assumption; the maintenance cost of enterprise search systems is based on an installation cost of those middleware search engines whose main characteristic is said to be simplicity of installation. We employed multiple search engines and performed experiments. We acquired results that the maintenance cost required for the installation of search engines. The results confirmed that our assumption is true to some extent.