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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 253 records · Page 14
All sourcesNASA NTRSDOE OSTI
DOE OSTI2011

Electrical Power Grid Delivery Dynamic Analysis: Using Prime Mover Engines to Balance Dynamic Wind Turbine Output

This paper presents an investigation into integrated wind + combustion engine high penetration electrical generation systems. Renewable generation systems are now a reality of electrical transmission. Unfortunately, many of these renewable energy supplies are stochastic and highly dynamic. Conversely, the existing national grid has been designed for steady state operation. The research team has developed an algorithm to investigate the feasibility and relative capability of a reciprocating internal combustion engine to directly integrate with wind generation in a tightly coupled Hybrid Energy System. Utilizing the Idaho National Laboratory developed Phoenix Model Integration Platform, the research team has coupled demand data with wind turbine generation data and the Aspen Custom Modeler reciprocating engine electrical generator model to investigate the capability of reciprocating engine electrical generation to balance stochastic renewable energy.

17 WIND ENERGY↗
NASA NTRS1994

Mars methane engine

The feasibility of an internal combustion engine operating on a mixture of methane, carbon dioxide, and oxygen has been verified by previous design groups for the Mars Methane Engine Project. Preliminary stoichiometric calculations examined the theoretical fuel-air ratios needed for the combustion of methane. Installation of a computer data acquisition system along with various ancillary components will enable the performance of the engine, running on the described methane mixture, to be optimized with respect to minimizing excess fuel. Theoretical calculations for stoichiometric combustion of methane-oxygen-carbon dioxide mixtures yielded a ratio of 1:2:4.79 for a methane-oxygen-carbon dioxide mixture. Empirical data shows the values to be closer to 1:2.33:3.69 for optimum operation.

Bui, Hung↗
DOE OSTI2021

Engine system and method including first and second turbochargers

An engine system includes an internal combustion engine having an intake passage, a first set of combustion chambers, a second set of combustion chambers, a first exhaust passage fluidly connected to the first set of combustion chambers, and a second exhaust passage fluidly connected to the second set of combustion chambers. The engine system includes a first turbocharger including a first compressor and a first turbine. The engine system also includes a second turbocharger including a second compressor and a second turbine, the second compressor connected in series with the first compressor, and the second turbine being in fluid communication with the second exhaust passage. The first and second turbines are connected in parallel such that the first turbine only receives exhaust flow from the first set of combustion chambers, and the second turbine only receives exhaust flow from the second set of combustion chambers.

Lusardi, Christopher↗
DOE OSTI2022

Chemical Kinetics Underlying the Sooting Tendency and Auto-Ignition Characteristics of Linear, Branched, and Cyclic Ether Compounds

Biofuels present opportunities for improving the performance and reducing emissions from internal combustion engines by incorporating oxygenated functional groups to the fuels. Among various oxygenates, ethers have been recognized as promising candidates for an alternative to conventional diesel fuel owing to their higher reactivity and lower sooting tendency. The detailed guidelines for designing ethers, however, have not been fully discussed, even though their combustion characteristics are sensitive to the molecular structure. This study was devoted to exploring the structure-property relationships, particularly focusing on the cetane number and yield sooting index, using five linear, branched, and cyclic ethers: di-amyl-ether, 4-butoxy-heptane, 3,3-dimethyl-oxetane, 2-ethyl-4-methyl-1,3-dioxolane, and 2-isopropyl-4-methyl-1,3-dioxolane. First, we examined the chemical kinetics underlying the sooting tendency of the test fuels. The combustion product distribution was measured from flow reactor experiments at 750-1100 K, F=3, at atmospheric pressure. As a result, it was revealed that the sooting tendency is closely related to the size of hydrocarbon intermediates in the high-temperature regime (>1000 K); that is, larger hydrocarbons lead to more soot precursor formation. The underlying chemistry determining the size of the hydrocarbons from the tested fuels was analyzed using reaction pathway analysis and quantum mechanics calculations, which showed that the branched and cyclic ether structures form abundant C3-C4 compounds. Moreover, the auto-ignition characteristics of the test fuels were studied using the flow reactor at low-temperature (400-700 K) and F=1. We found a clear difference in the combustion-product distribution from high and low reactivity fuels, which was then correlated to the systematic analysis of the key reaction energy barriers with the varying molecular structure.

BIOMASS FUELS,INORGANIC, ORGANIC, PHYSICAL, AND AN↗
NASA NTRS1984

Advanced high temperature materials for the energy efficient automotive Stirling engine

The Stirling Engine is under investigated jointly by the Department of Energy and NASA Lewis as an alternative to the internal combustion engine for automotive applications. The Stirling Engine is an external combustion engine that offers the advantage of high fuel economy, low emissions, low noise, and low vibrations compared to current internal combustion automotive engines. The most critical component from a materials viewpoint is the heater head consisting of the cylinders, heating tubes, and regenerator housing. Materials requirements for the heater head include compatibility with hydrogen, resistance to hydrogen permeation, high temperature oxidation/corrosion resistance and high temperature creep-rupture and fatigue properties. A continuing supporting materials research and technology program has identified the wrought alloys CG-27 and 12RN72 and the cast alloys XF-818 and NASAUT 4G-A1 as candidate replacements for the cobalt containing alloys used in current prototype engines. Based on the materials research program in support of the automotive Stirling engine it is concluded that manufacture of the engine is feasible from low cost iron-base alloys rather than the cobalt alloys rather than the cobalt alloys used in prototype engines. This paper will present results of research that led to this conclusion.

Titran, R. H.↗
DOE OSTI2010

Summary Report on the Transportation Combustion Engine Efficiency Colloquium Held at USCAR, March 3 and 4, 2010

This report summarizes results from an invited two-day colloquium of twenty-nine combustion engine experts from academia, industry, and national labs that was convened March 3rd and 4th, 2010, at the headquarters of the United States Council for Automotive Research (USCAR) in Southfield, Michigan. The colloquium was held at the request of The Department of Energy (DOE) Office of Freedom Car and Vehicle Technologies (OFCVT) to review and assess the current state of transportation combustion engine technology from theoretical and practical perspectives. In the ensuing discussions, the experts were able to reach a broad consensus on some important questions regarding current fuel efficiency limits. They also identified technology barriers and recommended specific near and longer-term R&D priorities for DOE's consideration. Internal combustion engines currently play a dominant role in U.S. transportation and are expected to continue to do so well beyond 2020 [1]. Because of this, the Department of Energy (DOE) has placed high priority on promoting technologies that maximize combustion engine fuel efficiency while minimizing greenhouse gas emissions. Identification of the most promising paths to achieve these goals has recently become more complicated as non-traditional transportation fuels and hybrid electric vehicles become widely available. To reassess the state of combustion engine science and identify new opportunities for technology breakthroughs, an invited colloquium of combustion engine experts was convened on March 3rd and 4th, 2010, at the headquarters of the United States Council for Automotive Research (USCAR) in Southfield, Michigan. The colloquium objectives were: (1) Review and assess the current state of transportation combustion engine technology from both theoretical and practical perspectives; (2) Arrive at a consensus on the theoretical and practical fuel efficiencies that can be achieved; and (3) Recommend near and longer-term R&D priorities for DOE to consider in developing their strategic planning for reaching efficiency goals. This report summarizes the main discussion points and recommendations that emerged from the meeting. Included are areas where there is widespread consensus and areas where there are still important technical uncertainties and wide ranging opinions.

33 ADVANCED PROPULSION SYSTEMS↗
NASA NTRS1972

Fluidic systems may improve combustion in automotive engines

Application of fluidic devices to reduce generation of noxious exhausts from internal combustion engines is discussed. Operation of fluidic system to provide bypass of fuel air mixture into heated loop to provide more complete combustion is explanined. Advantage lies in no moving parts required for fluidic by-pass action.

Mangion, C.↗
DOE OSTI2018

Understanding Soot Development and Thermal Stratification in Combustion Engines through Hyperspectral Non-linear Optical Diagnostics Development

Progress towards next-generation internal combustion engine technologies is dramatically hindered by the complexity of both simulating and measuring key processes, such as thermal stratification and soot formation, in an operating prototype. In general, spectroscopic methods for in-operando probing become limitingly complex at the high pressures and temperature encountered in such systems, and numerical methods for simulating device performance become computationally expensive due to the turbulent flow field, detailed chemistry, and range of important length-scales involved. This report presents parallel experimental and theoretical advances to conquer these limitations. We report the development of high pressure and high temperature ultrafast coherent anti-Stokes Raman spectroscopy measurements, up to a pressure and temperature regime relevant to engine conditions. This report also presents theoretical results using a stochastic one-dimensional turbulence (ODT) model providing insight into the local thermochemical state and its consequences by resolving the full range of reaction-diffusion scales in a stochastic model.

36 MATERIALS SCIENCE↗
NASA NTRS1978

Hydrogen-fueled engine

A hydrogen-oxygen fueled internal combustion engine is described, which utilizes an inert gas, such as argon, as a working fluid to increase the efficiency of the engine, eliminate pollution, and facilitate operation of a closed cycle energy system. In a system where sunlight or other intermittent energy source is available to separate hydrogen and oxygen from water, the oxygen and inert gas are taken into a diesel engine into which hydrogen is injected and ignited. The exhaust is cooled so that it contains only water and the inert gas. The inert gas in the exhaust is returned to the engine for use with fresh oxygen, while the water in the exhaust is returned to the intermittent energy source for reconversion to hydrogen and oxygen.

Laumann, E. A.↗
DOE OSTI2016

Dedicated EGR engine with dynamic load control

An internal combustion engine comprises a first engine bank and a second engine bank. A first intake valve is disposed in an intake port of a cylinder of the first engine bank, and is configured for metering the first flow of combustion air by periodically opening and closing according to a first intake valve lift and duration characteristic. A variable valve train control mechanism is configured for affecting the first intake valve lift and duration characteristic. Either a lift or duration of the first intake valve is modulated so as to satisfy an EGR control criterion.

42 ENGINEERING↗
DOE OSTI2020

Spark-ignited direct-injection engine combustion systems

A direct-injection stratified charge internal combustion engine includes a combustion cylinder to receive an air-fuel mixture, and an air intake port to inlet air into the combustion cylinder. The direct-injection engine also includes a fuel injector configured to deliver fuel within the cylinder in a spray pattern substantially aligned to a cylinder central axis to create the air-fuel mixture. A spark igniter is located within a path of the spray pattern to ignite combustion of the air-fuel mixture. The direct-injection engine further includes a movable piston defining a lower boundary of the combustion cylinder to contain the combustion of the air-fuel mixture. The piston is configured to include a bowl portion having local geometric features located on an intake port side of the combustion cylinder to redirect fluid flow towards a vortex in fluid communication with a combustion location near the cylinder central axis.

42 ENGINEERING↗
DOE OSTI2020

Engine Combustion System Optimization Using Computational Fluid Dynamics and Machine Learning: A Methodological Approach

Gasoline compression ignition (GCI) engines are considered an attractive alternative to traditional spark-ignition and diesel engines. Here, a Machine Learning-Grid Gradient Ascent (ML-GGA) approach was developed to optimize the performance of internal combustion engines. ML offers a pathway to transform complex physical processes that occur in a combustion engine into compact informational processes. The developed ML-GGA model was compared with a recently developed Machine Learning-Genetic Algorithm (ML-GA). Detailed investigations of optimization solver parameters and variable limit extension were performed in the present ML-GGA model to improve the accuracy and robustness of the optimization process. Detailed descriptions of the different procedures, optimization tools, and criteria that must be followed for a successful output are provided here. The developed ML-GGA approach was used to optimize the operating conditions (case 1) and the piston bowl design (case 2) of a heavy-duty diesel engine running on a gasoline fuel with a research octane number (RON) of 80. The ML-GGA approach yielded >2% improvements in the merit function, compared with the optimum obtained from a thorough computational fluid dynamics (CFD) guided system optimization. The predictions from the ML-GGA approach were validated with engine CFD simulations. This study demonstrates the potential of ML-GGA to significantly reduce the time needed for optimization problems, without loss in accuracy compared with traditional approaches.

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2010

A Study of a Diesel Engine Based Micro-CHP System

This project, funded by New York State Energy Research and Development Agency (NYSERDA), investigated the potential for an oil-fired combined heat and power system (micro-CHP system) for potential use in residences that use oil to heat their homes. Obviously, this requires the power source to be one that uses heating oil (diesel). The work consisted of an experimental study using a diesel engine and an analytical study that examined potential energy savings and benefits of micro-CHP systems for 'typical' locations in New York State. A search for a small diesel engine disclosed that no such engines were manufactured in the U.S. A single cylinder engine manufactured in Germany driving an electric generator was purchased for the experimental work. The engine was tested using on-road diesel fuel (15 ppm sulfur), and biodiesel blends. One of the main objectives was to demonstrate the possibility of operation in the so-called HCCI (Homogeneous Charge Compression Ignition) mode. The HCCI mode of operation of engines is being explored as a way to reduce the emission of smoke, and NOx significantly without exhaust treatment. This is being done primarily in the context of engines used in transportation applications. However, it is felt that in a micro-CHP application using a single cylinder engine, such an approach would confer those emission benefits and would be much easier to implement. This was demonstrated successfully by injecting the fuel into the engine air intake using a heated atomizer made by Econox Technologies LLC to promote significant vaporization before entering the cylinder. Efficiency and emission measurements were made under different electrical loads provided by two space heaters connected to the generator in normal and HCCI modes of operation. The goals of the analytical work were to characterize, from the published literature, the prime-movers for micro-CHP applications, quantify parametrically the expected energy savings of using micro-CHP systems instead of the conventional heating system, and analyze system approaches for interaction with the local electric utility. The primary energy savings between the space heating provided by a conventional space heating system with all the required electrical energy supplied by the grid and the micro-CHP system supplemented when needed by a conventional space heating and the grid supplied electricity. were calculated for two locations namely Long Island and Albany. The key results from the experimental work are summarized first and the results from the analytical work next. Experimental results: (1) The engine could be operated successfully in the normal and HCCI modes using both diesel and biodiesel blends. (2) The smoke levels are lower with biodiesel than with diesel in both modes of operation. (3) The NOx levels are lower with the HCCI mode of operation than with the normal mode for both fuels. (4) The engine efficiency in these tests is lower in the HCCI mode of operation. However, the system parameters were not optimized for such operation within the scope of this project. However, for an engine designed with such operation in mind, the efficiency would possibly be not lower. Analytical results: (1) The internal combustion engine (diesel engine in this case) is the only proven technology as a prime mover at present. However, as noted above, no U.S. engine is available at present. (2) For both locations, the use of a micro-CHP system results in primary energy savings. This is true whether the CHP system is used only to supply domestic hot water or to supply both hot water and space heat and even for a low efficiency system especially for the latter case. The size of the thermal storage (as long as it above a certain minimum) did not affect this. (3) For example, for a 2 kW CHP electrical efficiency of 25%, a typical house on Long Island will save about 30MBtu of energy per year for a combined space heat and domestic hot water system. This corresponds to annual energy savings of about 210 gallons oil equivalent per (4) The savings increased initially with the power capacity of the prime-mover, but flattened out at around 2 kW power output suggesting that a low power engine like the one tested is a good choice. (5) Reverse metering, that is, power returned to the electric grid when produced in excess of the local load, increased the primary energy savings significantly when using a 3kW to 5kW system with high fuel-to-electric efficiency. (6) In view of the current interest in plug-in electric or hybrid vehicles, the impact of night-time recharging on the micro-CHP operation was considered. Obviously, it will reduce the amount reverse metered and without reverse-metering, the primary energy savings were increased significantly. (7) The micro-CHP systems can contribute to the decrease of the carbon emissions of the local utility even with the use of diesel fuel and much more so with biodiesel use.

02 PETROLEUM↗
DOE OSTI2019

Control of Hybrid Power Unit with a Mechanical Transmission in High-Speed Caterpillar Vehicles

Abstract—: The properties of a hybrid power unit in which a mechanical transmission rigidly connects the internal combustion engine to the driving wheels are considered. In this transmission, the torque created by the parallel electric field is summed with the torque generated by the engine in the event of overloading. The control algorithms developed for the electric power prevent its opposition to the mechanical power under any circumstances.

42 ENGINEERING↗
NASA NTRS1990

Hot Wax Sweeps Debris From Narrow Passages

Safe and effective technique for removal of debris and contaminants from narrow passages involves entrainment of undesired material in thermoplastic casting material. Semisolid wax slightly below melting temperature pushed along passage by pressurized nitrogen to remove debris. Devised to clean out fuel passages in main combustion chamber of Space Shuttle main engine. Also applied to narrow, intricate passages in internal-combustion-engine blocks, carburetors, injection molds, and other complicated parts.

Ricklefs, Steven K.↗