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When hydrogen gas is used as the fuel, only water is formed as the byproduct. In addition to emitting ultralow or zero emissions, fuel cells offer high energy conversion efficiency, low noise level, and low vibration. The Norwegian energy system is based on electricity from renewable energy sources and mainly hydropower. Renewable energy output is strongly affected by the weather conditions, among other factors, and the supplies fluctuate accordingly. There is a need for a means to store and use the renewable energy surplus. In addition, from a technical point of view Norway still has potential to further develop hydro and wind power.

Excess power can be used for production of hydrogen through water electrolysis, which in turn can fuel different means of transportation, such as shipping. This paper aims at contributing to the research body on the use of hydrogen and fuel cells in shipping. First, a short introduction to hydrogen fuel and fuel cells is given. Then, an elaboration on pros and cons of powering vessels with fuel cells is presented. After providing an overview of current marine applications of fuel cells, the paper discusses potential vessels, which can benefit from this technology.

Finally, the environmental benefits of using fuel cells are shown through a preliminary case study. Data from the Automatic Identification System AIS in the Norwegian waters is used for estimating operational profile of a vessel, its current emissions, and potential emission reduction by using hydrogen and fuel cells.


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The results of this study show the potential of hydrogen and fuel cells in reducing emissions of shipping and set forth the research gaps. Use interactive graphics and maps to view and sort country-specific infant and early dhildhood mortality and growth failure data and their association with maternal.

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Sign In. Search Advanced Search. Paper No. OMAE, pp. VT09A; 9 pages doi Topics: Fuel cells , Hydrogen , Emissions. Purchase this Content. Learn about subscription and purchase options. Check Out Now Continue Browsing. For smaller engines, because of less favorable geometric characteristics such as surface area to volume ratios and friction factors, the peak efficiency is less than for larger engines; however, as with the larger engines the highest efficiencies are achieved at high load.

In general the efficiency of the engine decreases as its operating condition moves away from high loads into lower-load operating regimes. Despite the fact that some engines are approaching their practical maximum efficiencies, there is still room for improvement. Big large-bore, long-stroke engines have peak efficiencies that indeed are very near their practical limits.

There is little opportunity to improve their peak efficiencies further. Engines used in light-duty vehicles will have lower practical maximum efficiencies than big engines, and the current values of their peak efficiencies are not as close to their practical maximums. The opportunities for improvements in smaller engines lie in activities to push their peak efficiencies closer to their practical maximum limits and efforts to achieve these higher efficiencies over a large portion of the engine operating regime.

The ACECTT has set program targets of efficiency gains of 20 percent by relative to a baseline engine when operating over a prescribed set of operating conditions. Since the efficiency typically drops as the operating condition moves away from the point of maximum efficiency—that is, moves to lower loads—there is much that can be done to improve the overall cycle efficiency. If the high-load efficiency of the engine can be replicated at lower loads, the overall cycle efficiency of the vehicle will improve, which would result in significant reductions in fuel consumption and emissions.

Furthermore, as engine evolution takes place, changes in combustion processes and technologies for overcoming practical constraints in these smaller engines—like being able to operate knock free at higher compression ratios—will improve the peak engine efficiency. These improvements in peak efficiency could then be promulgated over the entire operating cycle of the engine and act as an additional multiplier to improvements to the overall cycle efficiency.

Incorporating technologies that accomplish these goals ca. Given the magnitude of the vehicle fleet powered by ICEs, fuel consumption and emission reductions introduced through ICE improvements would be multiplied by millions of vehicles per year, so the reduction in fuel consumption and emissions would be significant. As a transportation power plant the ICE is ideal for applications that demand sustained high power operation and long times or distances between refueling. However, even the most efficient engine will still need exhaust gas aftertreatment to ensure that the criteria tailpipe pollutants are below regulated limits over the entire vehicle operating domain.

So, the engine and the aftertreat-. Accomplishing this requires understanding all the energy flows, transformations, and work-potential dissipations exergy destruction that occur in the power train—that is, starting from the fuel leaving the fuel tank to the power being delivered to the wheels and then guaranteeing that the aftertreatment system can function effectively at the exhaust conditions leaving the engine cylinder. Achieving improvements in these areas pushes the boundaries of the current understanding of almost all the physical and engineering sciences. Pursuing such improvements is the focus of the engine combustion and aftertreatment research community.

It is manifest in such activities as hybridization of the power plants, downsized boosted engines, variable valve actuation, cylinder deactivation, and advanced combustion processes. In each of these applications the technical community is working both to increase the peak efficiency and to bring high-load engine efficiencies to vehicle operation that does not require high load engine operation.

As the engine efficiency is increased more of the fuel energy is converted to work and there is less energy leaving the engine in the exhaust stream. The lower energy content of the exhaust thermodynamically translates into lower exhaust gas temperatures.

This presents an additional challenge for the exhaust gas aftertreatment system. Not only is there need for higher effectiveness of the aftertreatment systems to reduce criteria pollutants, but also the aftertreatment systems need to achieve this effectiveness at lower temperatures. In addition, the fuel cycle needs to be part of the focus. Biomass-derived fuels, either as blends or drop-in components, have the potential to reduce total life cycle also referred to as C2G GHG emissions. Research is under way to explore potential synergies between fuel refining processes and fuel characteristics selected to enhance the combustion process while trying to achieve optimal C2G GHG emissions for the system as a whole.

For example, higher octane number fuels would allow engines to have higher compression ratios, which improves their efficiency and could eliminate the need for spark retard a control strategy to avoid engine knocking that is detrimental to efficiency. However, the extent to which this can be done, and the implications in the trade-offs in GHG emissions between the additional processing and potential costs necessary to achieve the higher octane number during the fuel production versus the lower fuel consumption achieved during engine operation, needs to be determined.

Fuels will also play an important role in achieving the carbon dioxide CO 2 reduction targets for the light-duty vehicle fleet by reducing the carbon footprint of the energy carrier itself. The advanced engine and combustion strategies under investigation by the ACECTT will enable significant CO 2 emission reduction; however, without an accompanying effort to reduce the carbon in the fuel it is unlikely that the CO 2 target can be met Farrell, Although the co-optimization.

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Reduce petroleum dependence by removing critical technical barriers to the mass commercialization of high-efficiency, emissions-compliant internal combustion engine ICE powertrains. Their activities focus on continued improvement of spark-ignition SI and compression-ignition engines working in conjunction with more effective aftertreatment systems, while continuing the development of more advanced, kinetically controlled, low-temperature combustion engine concepts.

The ACECTT activities are fundamentally dissecting and analyzing the energy flows within the engine-aftertreatment-power train system to address every energy transformation that occurs within the vehicle. This includes the energy flow in the fuel leaving the fuel tank, through its introduction into the cylinder, during the combustion and work extraction processes, through the aftertreatment system, and out the tailpipe. Attention is also directed at all energy flows that use work generated by the engine for functions other than driving the wheels—such as accessories, pumping and friction; or energy flows that leave the engine in a form other than work, such as heat transfer and exhaust flow.

Maximizing efficiency and minimizing emissions over the operating map of the vehicle is a complex challenge that requires detailed understanding of the fundamentals that govern these energy transformations, the degradations of the work-potential of the energy associated with these transformations—that is, exergy destruction—as well as being able to measure them via sensors and developing advanced control systems to optimize the energy management for the entire system. As an enhanced understanding of these energy flows, and their associated exergy destruction, is developed, it enables researchers to determine which irreversibilities can practically be pursued for reduction, and the extent to which efficiency improvements are possible by perfection of the energy transformation in question.

For example, the following have all been important in directing research and technology development activities: understanding the magnitude of the work that is lost due to the chemical reactions that release the chemical energy in the fuel, and realizing that this loss cannot be prevented with current technologies; or understanding the relative importance of the heat transfer from the engine during different portions of the combustion process; or being able to calculate the work that might be obtained by exhaust energy recovery systems; or understanding the trade-offs of different exergy destruction processes that lead to improved engine efficiency by keeping combustion temperatures low.


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These activities are made especially challenging because to. To address the interactions between fuels and the engine system U. A working group is less formal than a technical team. It does not have a roadmap or defined technical targets but instead offers structure for technical experts to discuss topics of interest. The ACECTT understands that advanced spark- and compression-ignition engines will be dominant in the near-term mobility fleet. The potential of advanced low-temperature combustion systems, also referred to by the ACECTT as chemical kinetics-dominated combustion, has been demonstrated in the laboratory Ra et al.

The technical team expects that the engine types used during the time period of focus for this program will be a mix of naturally aspirated hybrids and advanced downsized boosted architectures. That is, the ACECTT expects that in the near term the engines will have conventional four-stroke architectures with improved but relatively conventional spark-ignited flame propagation or diesel—type autoignition combustion systems.

Furthermore, the ACECTT believes that within each of these engine pathways, the combustion strategies will be one of the following:. Each of these combustion strategies depends on the characteristics of the fuels being used. Fuel characteristics such as resistance or propensity to autoignite and how that propensity changes with the conditions in the cylinder, burning velocity, tendency to form particulate matter, and heat of vaporization will impact the effectiveness of the combustion strategy in converting the energy in the fuel to.

Through the Fuels Working Group, the ACECTT is also attempting to identify optimal fuel characteristics for the different combustion strategies and determining if the introduction of such fuels could be easily integrated with the current fuel infrastructure and legacy fleets. These research issues are also part of the DOE Co-Optima initiative; these are areas where Co-Optima funding is being directed toward projects that support U.

DRIVE goals. For premixed flame dominated SI engines, pursuing dilute combustion is recommended. Combustion in near-term dilute SI engines will be dominated by the propagation of a flame front through reactants that are largely premixed. The dilution of the charge, either with excess air lean or with exhaust gas recirculation EGR promotes higher efficiency because the combustion temperatures are lower than those occurring in undiluted, stoichiometric 1 spark-ignited combustion. The lower combustion temperatures result in a ratio of specific heats, gamma, that is higher than would occur if the gas temperatures were higher.

Thermodynamically this leads to a higher work extraction per unit of piston motion during the expansion stroke, as well as lower heat transfer and exhaust enthalpy losses. It is also beneficial because the cylinder-out oxides of nitrogen NO x emissions are lower owing to the lower temperatures, so less NO x reduction is needed from the aftertreatment systems. Particulate emissions are also low because the reactants are largely premixed, so particulate filtration requirements are less.

Low emissions from diesel combustion can be achieved by using EGR with advanced mixing and injection strategies, which must then be coupled with effective aftertreatment systems. Enhanced understanding of the interactions among the EGR, advanced injection strategies, and in-cylinder fluid motion is needed to promote combustion conditions that minimize the in-cylinder regions of high-soot and high-NO x formation. LTC is used here as the name for the generic combustion process that is largely flameless, volumetric autoignition that is controlled by chemical kinetics. Many approaches are being investigated to achieve and control this staging of the autoignition, and this.

Successfully creating this situation inside the combustion chamber depends on the state of the gases at the start of compression and the physical and chemical characteristics of the fuel. The litany of acronyms that has appeared in the literature is an indication of the different approaches that can be taken to achieving this combustion mode. The benefit of LTC is higher efficiency, for the same reasons cited earlier in the discussion of dilute gasoline engines, and very low NO x and soot.

As the engine becomes more efficient, more of the fuel energy is being converted to shaft work, so less energy is leaving the engine as exhaust enthalpy. Consequently, the engine exhaust is at a lower temperature than it is from a less efficient engine. This presents an additional challenge for the aftertreatment system. Industry is aggressively pursuing and making progress in lowering the light-off temperatures and temperature window of full functionality for the aftertreatment systems. Ideally one would like aftertreatment systems that are fully functional at cold start temperatures.

For this reason the ACECTT is advocating continued research into perfecting aftertreatment systems that work at lower temperatures. This is needed for all aftertreatment systems: three-way catalysts, lean NO x traps, selective catalytic reduction systems for NO x , and particulate filters. To benchmark progress and motivate research efforts the ACECTT has established research targets for for both engine efficiency improvements and exhaust emission levels. Engine concepts shall be commercially viable and meet emissions standards. The research targets have been broken down for the specific engine types found in the market today, projecting that near-term engines will be further developments of current state-of-the-art engines.

These engine-specific research targets are shown in Table The targets are stated in terms of improvements relative to a baseline for each engine type. As shown in Table , the technical team has highlighted the operating points for each of the different engine pathways. Highlighted cell represents most relevant operating point for that technology pathway. The highlights represent the most important operating conditions at which research engines of that type should be thoroughly evaluated. The research targets for emissions were established based on current and pending regulations, as shown in Figure At the request of the committee the U.

Fuel Cells

This list consists of 40 projects and is given in Table The ACECTT has identified the fundamental areas barriers for which enhanced understanding would facilitate progress toward their research targets for each of the projects listed in Table This discussion is presented in the context of the three individual combustion strategies, the development of enhanced computational fluid dynamic CFD capabilities, and the challenges of future aftertreatment systems.

The entries in Table have been color coded to show the connection of the projects in the table to the general descriptions of the challenges for the different combustion strategies, CFD development, and aftertreatment systems. If a project advances more than one category of the general description it is shown with multiple color codes. Further detail on the individual projects in the table can be found in the presentations for the VTO given at the DOE and AMRs with the project numbers contained in Table Acronyms defined in Appendix D. Premixed flame dominated, dilute combustion engines are currently constrained by knock-limited operating regimes, lack of combustion robustness, low combustion rates, low exhaust enthalpy, gas exchange complexity such as EGR and air handling , and high emissions of hydrocarbons HCs and NO x.

Lean or dilute combustion offers higher efficiency; however, as one pushes the limits of dilution it is more difficult to initiate and maintain the flame. Once the flame is established the traditional approach of enhancing the burning velocity by increasing turbulence is limited, because it is easier to extinguish the flame under the higher fluid shear that occurs when turbulence is increased. If the dilution is obtained through EGR, either internal or external, the lack of homogeneous composition of the EGR with the intake air can cause flame extinction much more easily than for stoichiometric flames.

Similarly, the flame propagation is more sensitive to mixture inhomogeneous conditions that occur between the fuel and the air in the combustion chamber under conditions of high dilution. Cycle-by-cycle variations during the engine operation now become a more serious problem. Because the combustion is less stable and more easily extinguished, unburned hydrocarbons and carbon monoxide CO emissions can become excessive.

As boost is used to increase the power density of the engine, knock limits are often reached during high load operation. This limits the potential improvement obtainable from the engine because actions taken to avoid knocking operation compromise performance. Finally, when operating under very dilute conditions the exhaust temperature becomes so low that it taxes the capability of the aftertreatment system. If the high dilution is achieved through lean operation, three-way catalysts are no longer effective for NO x control, so lean NO x reduction would need to be implemented.

Projects that contribute to further understanding of these phenomena are color coded green in Table Diesel engines have a potential efficiency advantage over premixed flame-dominated engines but they also have significant challenges. The ACECTT has identified the most critical challenges being faced by engineers working on diesel engines as follows: in-cylinder NO x and soot control, EGR and air handling, fuel injection and control systems, and the cost and complexity of the systems. The characteristics of the fuel injection process play an important role in achieving clean diesel combustion.

The intricate details of the internal geometry of the injector and how it affects the fuel flow leaving the injector play an important role in the early entrainment and mixing of the fuel and air in the immediate vicinity of the injector tip. This also impacts the symmetry of the spray pattern among the individual injector nozzle-hole plumes.

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The early behavior of the individual fuel plumes leaving the nozzle determine the air-to-fuel ratio of the portion of the spray that is first to experience autoignition, which in turn has a high impact. The formation of the particulate at this early part of the combustion process subsequently dictates the characteristics of the soot-NO x trade-off of the engine. EGR is an important aspect of the soot-NO x trade-off of the engine. Since diesel engines typically do not have throttles in the intake manifold, the pressure difference between the intake and the exhaust manifold is minimal.

Engine performance is easily compromised by efforts made to induce the exhaust gas to flow between the manifolds when there are either insufficient or adverse pressure gradients. Different approaches to getting the exhaust gas from the exhaust to the intake manifold, like high-pressure and low-pressure loops, along with the challenges this imposes on the operation of the boosting system and the resulting impact on the pumping work, are motivating much technical research and development. Projects listed in Table addressing these fundamental challenges are color coded orange. Engines operating using LTC processes have the potential for very high efficiency with low cylinder-out emissions.

However, there are significant challenges to implementing this combustion mode in an engine. Chief among them are high combustion noise, achieving combustion robustness, high engine-out HCs and CO, transient combustion control and emissions, cold start ability, obtaining a wide speed and load operating range, and cost and complexity. The combustion initiation for LTC operation depends on the chemical kinetic autoignition of a partially premixed air-fuel mixture. There needs to be a certain degree of nonuniformity within the air-fuel mixture in the cylinder to obtain acceptable combustion.

If the mixture is too uniform the entire mixture autoignites at once and the rate of combustion is excessive. If the mixture is too stratified the combustion can either become excessively long or fail to go to completion. The nonuniformity of the mixture can be manipulated in many ways: nonuniformity in temperature, in air-fuel ratio, in oxygen concentration, or in fuel reactivity.

In addition, the level of the nonuniformities in the cylinder necessary for good combustion is intimately linked to the characteristics of the fuel. This makes control of all aspects of the in-cylinder conditions extremely important, so engine controls and transients are a major technical challenge. Even if LTC modes were used in hybrid applications there would still be transients because of the stop-start nature of the engine operation in hybrid vehicles. Projects that contribute to further understanding of these phenomena are color coded red in Table New understandings from research are integrated into the simulations, which in turn are used to offer higher-fidelity interpretations of the.

In the quest of ever better engine performance the need for deeper understanding of the governing fundamentals continues to grow, which subsequently requires higher resolution and more precise submodels to be integrated into the simulations. For example, kinetic models capable of predicting the impact of different fuel compositions on engine performance; higher-fidelity numerical submodels such as fluid turbulence models simulating mixing and dissipation to ever smaller physical scales; combustion models that can capture the transition between flame propagation, mixing-controlled burning, and LTC energy release; better submodels for the heat transfer processes in the cylinder; more accurate emission models; more robust and faster numerical algorithms; and increased capability for program parallelization are examples of important advancements that would make the simulation efforts even more valuable than they are now.

Projects listed in Table addressing these fundamental challenges are color coded blue. As the engines are made more efficient the energy in the exhaust gases leaving the engine decreases, which requires the aftertreatment systems to function at lower temperatures. Furthermore, as the number of people living in urban areas increases, vehicle density in those areas increases.

This results in a larger input of engine exhaust into the urban environment, which drives the need for even lower regulatory limits on criteria pollutants. Consequently, the exhaust gas aftertreatment systems need to be made more effective and capable of functioning at lower temperatures than current systems. This establishes the research priorities for exhaust gas aftertreatment systems. The aftertreatment systems are integral to the engine and power train; they need to be effective at temperatures below the current operating temperatures of o C to o C, reach light-off temperatures as quickly as possible, be resilient to poisoning from contamination, use minimal precious metals, and effectively filter particulate matter down to a size of 23 nm, the particle diameter above which the European number regulations are enforced, and they need to be easily regenerated.

Projects that contribute to further understanding of these phenomena are color coded yellow in Table The deeper understanding of the thermodynamics, fluid mechanics, heat transfer, combustion physics, fuel chemistry, and catalysis that is sought in the research projects in Table is necessary to develop better engine components and exhaust gas aftertreatment systems, but it is only part of the solution to achieve maximum performance with minimal environmental impact from the vehicle.

The engine, exhaust gas aftertreatment components, and the power train must work as an optimized system, which presents complex challenges in total system control. These challenges not only push current capabilities in control theory but also. The projects that the ACECTT advocates supporting strive to enhance the analysis capabilities and fundamental understanding of the technical barriers to more efficient and environmentally benign engines. As can be seen from the list of projects with which the U.

In addition to the fundamental research activities, the ACECTT also engages in industry cost-shared demonstration programs. In doing this, valuable learning occurs as to the subtleties of interactions between the different system components and power train controls once they are completely integrated into a product.

It also helps guide the manufacturers as to the time frame when different advanced technologies might be commercially viable. Within U. DRIVE four such activities have been identified:. Overall the ACECTT is engaged in a broad array of research projects, ranging from fundamental laboratory investigations, to understanding subtle phenomena occurring within commercially available technologies, to exercises in advanced technology integration for market readiness assessment.


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  6. With such a broad range of research activities it is important to make sure that efforts are synergistic and not duplicative, and that time horizons and risk factors of the research are appropriate to the organization performing the work. The advanced technology integration projects shown earlier can be very informative and are not something that industry would do when high-risk unproven technologies are being used. The national laboratories are not involved in these activities, which is appropriate.

    Within the ACECTT programs some of the research within the national laboratories involves use of already developed engine technologies. It is important that such work address underlying fundamentals that need to be better understood, and if understood would open up new performance possibilities. It should be work that industry would not or could not do on its own and that benefits the technical community at large.

    The principal barrier to achieving U. The ACECTT has established a series of networks to facilitate communication and knowledge transfer within the appropriate technical communities. By interfacing with USCAR there is regular information exchange on fundamental needs as well as feedback on the programs considered to be part of the U. DRIVE portfolio. University research is also integrated with the MOU. The Engine Combustion Network is an excellent example of a predominantly web-based facilitation of data and CFD analysis exchange for better computer models of spray combustion.

    Over 16 international teams share experimental data, CFD approaches, codes, and actual model submissions for a well-characterized set of injectors operating under accurately prescribed conditions. DRIVE estimates that the combined effort has accomplished 15 years of research progress in approximately 3 years Howell, It has proven to be a very effective venue for technical exchange between broad scopes of participants.

    In addition to the preceding structured programs, which have regularly scheduled interactions, the ACECTT has established collaboration through special workshops, such as the following:. Through the collaborations, working groups, workshops, and review participation they stay informed of the critical research needs of the industry partners and are effectively facilitating the knowledge exchange that supports the industry goals of more efficient, cleaner vehicles.

    The assessment of the committee is that the U. When asked by the committee, the ACECTT submitted the following list of accomplishments for their combustion and aftertreatment activities:. The barrier to further improvement in engine efficiency and more effective aftertreatment systems continues to be the incomplete understanding of the detailed fundamentals of the thermodynamic, fluid mechanic, heat transfer, chemical kinetic, and combustion physics processes that occur within the engine and the aftertreatment systems.

    There should be a more formal collaboration established among the industry stakeholders, university stakeholders, and the DOE researchers doing the development work for KIVA IV. Partnership Response. Also, several companies have inquired about starting more formal collaborations with LANL.

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    LANL has a modular and object-oriented engine modeling code in development that will be more predictive and much more robust, while allowing for very rapid grid generation without compromising accuracy. Committee Assessment of Response to The committee thanks U. The committee is aware that DOE held a high-performance computing workshop in August with invitations to all stakeholders. The outcomes of the workshop were a prioritized list of attributes heralded by industry as necessities, and plans for commercialization of the code DOE is developing with a goal of maintaining mostly open-source source code so university students can continue to modify and gain familiarity with the code for their own purposes and training.

    These outcomes address the concerns raised by the committee in Recommendation of the Phase 4 review. The committee believes it is appropriate for the federal government to maintain a role in combustion and emissions control research. As described in the introduction to this section, there is still significant opportunity to reduce the fuel consumption and environmental impact of ICE-powered vehicles, so it is important to keep an active research program in this area.

    Developing the enhanced understanding and tools to do this pushes the state of the art in almost all physical and engineering sciences. Finding DRIVE organization. They understand the technical barriers that need to be overcome to further increase the efficiency and environmental friendliness of ICE-powered vehicle systems.

    To guide the technical work toward overcoming technical barriers to higher efficiency, the advanced combustion and emissions control technical team ACECTT has established stretch efficiencies goals for for peak and intermediate engine loads for the three types of engine power train systems they expect to be most prevalent in the near term: hybrid applications, naturally aspirated, and downsized boosted engine systems.

    The ACECTT is also engaged in research activities in chemical kinetic development, and promoting a more fundamental understanding of the interaction between fuel characteristics—such as Research and Motor Octane number, heat of vaporization, etc. This work is aimed at facilitating the integration of advanced kinetically controlled combustion processes, i. The ACECTT focus for both near- and longer-term research is centered on conventional four-stroke engine architectures. However, work on alternative engine architectures is taking place.

    Some of that work is under DOE funding, and claims are being made in the literature of potential efficiency and environmental impact improvements for these different engine architectures Redon et al. Recommendation The advanced combustion and emissions control technical team should be proactive in seeking out and assessing data on the performance of alternative engine architectures and concepts that will allow benchmarking against those within their current research portfolio. The ACECTT has recognized that fuel characteristics can be a contributor to improving engine efficiency and reducing environmental impact.

    The ACECTT is engaged in a broad array of research projects ranging from fundamental laboratory investigations, to understanding subtle phenomena occurring within commercially available technologies, to exercises in advanced technology integration for market readiness assessment. The committee believes that the ACECTT is doing a good job making sure the individual efforts are synergistic and not duplicative and that the time horizons and risk factors of the research are appropriate to the organization performing the work.

    The U. As a result, the development of these alternative production methods has ensured the use of petroleum as one of the primary transportation fuels for light-duty vehicle applications for decades to come. DOE and U. The potential for ample amounts of petroleum-based fuel for use in transportation has increased concerns regarding the issue of GHG emissions and their effects on climate change. For that reason, it is critical that engine design and fuel composition be considered a system in developing new technologies for improving vehicle fuel efficiency and reducing CO 2 emissions.

    To this end, as described earlier in this chapter, the U. DRIVE, h. These goals require identifying how drop-in fuels will impact advanced combustion and emissions control strategies as well as identifying practical, economic fuels and fuel-blending components with potential to directly replace significant amounts of petroleum U. Parasitic losses in the engine and other driveline components are also a source of wasted fuel energy. Fenske et al. To address this issue, DOE is also funding research on advanced, low-friction lubricant formulations in support of U.

    DRIVE goals and objectives. Petroleum fuel and lubricant research in support of the U. Currently there are eight projects being con-. However, as described earlier in this chapter, there are additional advanced combustion projects that also include the evaluation of fuel formulations in meeting engine efficiency and emissions goals. These projects are distributed over a number of national laboratories, original equipment manufacturers OEMs , and numerous suppliers.

    In the case of fuel research, the projects are focused on not only the combustion and spray characteristics of petroleum-based fuels both gasoline and diesel but also the characteristics of petroleum-biofuel blends. Experimental data collected from individual projects are used to develop injector spray flow patterns and kinetic models of fuel combustion that are subsequently used in large CFD calculations of in-cylinder combustion.

    These programs are important in providing a methodology for efficiently evaluating a large number of potential options for fuel composition, injection strategies, and cylinder designs. The national laboratories have been able to develop new analytical techniques for identifying the combustion properties of fuel blends e. In most cases the analytical facilities of the national laboratories greatly exceed the facilities at supplier and OEM laboratories and for this reason the use of the national laboratories for this work is appropriate in meeting U.

    In support of the U. As described to the committee Howell, , these targets include the following:. In order to achieve these goals, the VTO has funded the specific projects listed in Table Although most of these projects are managed by individual national laboratories, the project teams include significant participation by U. In addition, DOE has also funded supporting research at academic laboratories throughout the United States. This solicitation was restricted to U. The final selection of academic research teams for this solicitation involves researchers from 14 universities.

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    Using teams made up of governmental, industrial, and academic researchers, this research is intended to promote the rapid. As described earlier in this chapter, U. DRIVE fuel company. Within the U. Working groups do not conduct research according to a roadmap, nor do they have specific technical targets. Instead, they support the goals of related technical teams by coordinating research projects among interested parties both within and beyond U. These focus areas are designed to evaluate potential properties of lower carbon fuels for future, high-efficiency engines and combustion regimes meeting ACECTT targets.

    These focus areas are as follows Farenback-Brateman, et al. As an example of how the FWG will address these focus areas, the ACECTT has identified a set of specifications for an advanced gasoline formulation shown in Table , which it believes would greatly enhance spark-ignition engine performance due to allowing higher compression ratios and reducing the need for spark retardation.

    To determine if these specifications will in fact meet the purposes identified in Table , the FWG is actively involved, as part of their focus area 1, in collecting engine data intended to define the benefits of each specification. These engine tests are being conducted within OEM laboratories and national laboratories. In addition, the data collection efforts are being supported by several research projects being conducted within the Coordinating Research Council CRC.

    Recently, national laboratory personnel have also joined CRC working groups and contributed significantly to the identification of sur-. The FWG will also identify and document infrastructure implications of new fuel formulations and identify technical roadblocks to implementation.

    All of this effort is directly related to determining the efficacy and benefits of the FWG focus area 1. Similar efforts and research projects will also be developed to quantify the benefits of the other three FWG focus areas. Current fuels are predominantly petroleum based, and refinery systems have been optimized for producing the current mix of gasoline and diesel.

    Their respective properties have traditionally been defined by meeting regulatory requirements and agreements reached within consensus organizations like the American Society for Testing and Materials ASTM and between members of the vehicle and energy industries. However, from the per-. In addition, it is important to determine if optimization of fuel properties could further facilitate the introduction of advanced combustion processes, such as kinetically controlled, low-temperature combustion.

    A recent status report on the developments generated within the first year of the Co-Optima consortium has been published NREL, The introduction to this status report suggests that the objective to Co-Optima is. To arm industry, policymakers, and other key stakeholders with the scientific foundation and market intelligence required to make investment decisions, break down barriers to commercialization, and bring new high-performance fuels and advanced engine systems to market sooner.

    The status report maintains that the consortium will enable the introduction of new commercial fuel and engine technologies by As described in the following material, the committee understands that the Co-Optima initiative is a major undertaking and that meeting its stated goals, although well intended, will be difficult given the stated timeline.

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    Although the Co-Optima consortium is not a specific activity within U. DRIVE and therefore not a subject of this review, the existence of Co-Optima and its inclusion of many additional stakeholders with diverse interests raises several questions of importance to U. DRIVE such as how the initiative will be conducted, how decisions on experimental fuel properties and compositions will be made, and how advanced fuel specifications will be used. For example, if a set of fuel properties is identified to be useful in increasing engine efficiency or reducing C2G CO 2 emissions, will these properties be allowed or recommended for use in.

    Fuel effects on the durability of the fuel tank, pump, and injector systems will need to be verified. Correspondingly, energy companies will not introduce new fuels into the commercial marketplace without confidence that the engine systems that rely on such fuels will be available.

    There has been significant progress in meeting both fuel and lubricant goals in the 3 years since publication of the NRC Phase 4 review of U. In regard to fuel research accomplishments, the focus has clearly been on development of advanced fuel blends comprised of hydrocarbon and biofuel components. The RCCI operating range has been expanded to 75 percent of its theoretical maximum while maintaining low soot and NO x emissions when using this fuel blend. This same team has also quantified the benefits of high-octane E30 30 percent ethanol in gasoline in downsized, turbocharged, direct-injection four-cylinder engines employing high compression ratios.

    The IQT has also been modified to provide kinetic data at gasoline combustion conditions of high pressures and temperatures. E30 blends are shown to be compatible with high-efficiency, boosted, direct-injection, stratified-charge engine performance. Sjoberg also concludes that ultralean SI operation requires end-gas autoignition for high-combustion efficiency.

    Mueller at SNL has conducted a detailed research program directed at reducing soot generation in diesel engines by modifying fuel composition and combustion strategies Mueller, As part of a CRC program, a set of surrogate diesel fuels was developed, blended, and made available for laboratory test programs in combustion tubes and single-cylinder engines. An optical analytical technique, vertical-sheet, laser-induced incandescence, has been developed to analyze and quantify in-cylinder soot measurements.

    A diesel-biodiesel blend has been evaluated as an enabler for a leaner-lifted flame combustion strategy. In regard to achievements in lubricant research, a DOE contract with Ashland Oil Corporation has led to the development of a heavy-duty engine oil formulation that provides greater than 2. SAE 5W versions of this lubricant technology are predicted to provide greater than 2. Ashland has also developed an axle lubricant that can provide 0.

    These developments demonstrate significant progress in meeting the VTO goal of a 4. A research program led by Fenske at Argonne National Laboratory has focused on the development of methods for analyzing tribo-films that form on rubbing surfaces and affect friction and wear Fenske, Techniques including focused ion beam electron spectroscopy and X-ray absorption near-edge structure techniques have been used to identify the degree of amorphous or crystalline nature of additive films on wear surfaces.

    The DOE focus on petroleum fuels and lubricant research has developed into a well-structured portfolio of projects. There are no real barriers to conducting research on advanced fuel concepts under study at various national laboratories, suppliers, and OEM facilities. An additional challenge is to reduce driveline parasitic losses through the development of advanced lubricant formulations. The research programs currently under way are well structured to meet these challenges, but whether the program will meet its challenges according to the timeline proposed by the VTO is unknown.

    This is a very aggressive set of objectives. However, reaching consensus within a diverse group of government and commercial interests is going to be a severe challenge. It is not too early in planning to identify the process and criteria for selecting an optimum system. There were no recommendations dealing with petroleum-based fuels or lubricants in the NRC Phase 4 review. It is entirely appropriate for the federal government to be involved in research that affects two independent, major U. S industries, auto and energy. The national laboratories can serve a critical role as arbiter of conflicting data and disagreements regarding potential benefits.

    The introduction of new fuels into the marketplace that must precede, or at least. Participation of national laboratories personnel in these standards-setting processes would add significant technical resources and expertise to this effort and accelerate the standards-setting process. The Co-Optima initiative may help in reaching consensus on these challenging technical and economic issues, although more information is needed on how this program will deal with such issues.

    The portfolio of projects assembled by the U. Laboratory and dynamometer tests conducted at national laboratories are contributing to progress in meeting specific U. They are generating important data in support of development of combustion models using advanced fuels, different injection strategies, and combustion chamber designs. DOE needs to provide greater explanation of how the Co-Optima program will be managed. How are the research projects at the national laboratories set to meet the technical needs of the U.

    Engine manufacturers will not introduce vehicles that utilize advanced combustion systems without the assurance that suitable fuels are available for the new combustion technology. DRIVE on the. A plan for introduction of advanced combustion systems and fuels designed to increase transportation energy efficiency and reduce CO 2 emissions is required. As discussed in NRC b and other places, Congress established the Renewable Fuel Standard RFS in , which set a goal of using 36 billion gallons of biofuels per year in transportation applications by To meet this goal, Congress has provided tax credits and incentives for biofuels production.

    These credits and incentives generally remain in effect. This ethanol is added to gasoline in the United States, mostly at a concentration of 10 percent. In early , the EPA expanded a waiver to allow up to 15 percent ethanol in gasoline used to fuel and later model year light-duty vehicles.

    The EPA cannot force fuel stations to provide gasoline blends containing 15 percent ethanol without the approval of Congress, which at this time, it does not have. The use of 15 percent ethanol has been opposed by some global OEMs due to concerns over fuel system durability in older engines designed for 10 percent ethanol in gasoline.

    To date very little gasoline containing 15 percent ethanol has become available at commercial fuel pumps. The commercial production of cellulose-derived ethanol, envisioned in the RFS, is slowly being realized. The combined production of ethanol from these three plants could reach 60 million barrels per year. The plants are using technology that was developed in part at the NREL. The use of bio-based butanol is also being considered for transportation use. Butanol has better gasoline blending and vapor pressure characteristics than ethanol, while still providing a significant octane boost.

    Butanol can be produced from renewable biomass, and it can be produced from refinery operations that produce excess C4 hydrocarbons. However, the production of butanol from petroleum light ends in the refinery would not be considered a renewable fuel. The production of biodiesel essentially fatty acid methyl ester [FAME] and other esters is still minimal but continues to increase National Biodiesel Board, Although the process for production of FAME is well defined, there is.

    National laboratory research programs are defining the performance of both wood-derived bio-gasoline and bio-reformates in engine tests. Wood-derived gasoline is produced by gasifying wood residue, compressing the resulting syngas, and then catalytically reforming the components of the gas stream Farenback-Brateman et al. Bio-reformate components are produced from starch, sugar, or cellulosic feedstocks that are subjected to catalytic reforming with extra added hydrogen. DRIVE biofuel goals and targets are essentially the same as those described earlier in this chapter for petroleum-based fuels.

    If there is any difference, it is in the emphasis on the validation of biofuel components that might be blended into gasoline or diesel fuel to promote improved efficiency and reduced emissions. In addition, as with petroleum projects, the U. As indicated previously, most of the key achievements in regard to VTO fuel development projects since the last U.

    This research project is investigating the possibility of using long-chain oxygenates derived from biomass as drop-in fuel components for blending. The oxygenate candidates are being solicited from suppliers and are being evaluated in laboratory tests to determine fuel blend properties. In addition, the fuels are also being evaluated in both diesel and gasoline direct-injection GDI engine tests.

    Twenty-four different oxygenates have been considered. Partial results have demonstrated that phenolics and esters improve fuel lubricity. Ethers and ketones have no effect on lubricity. There is no effect of oxygenates on oxidation stability except for phenolics that act as antioxidants. Early engine test results have shown no effect of oxygen on particulate matter emissions. Cost challenges represent a substantial barrier to use of biofuels in commercial fuel blends.

    In the case of drop-in fuels derived from biomass, it has been reported that the cost of production is a major deterrent confronting commercialization of these fuel components Brown and Capareda, There have been no data presented that would indicate that this objective will be met on time. It appears that this is a challenge that will continue into the future.