4
Major Crosscutting Issues

Several major crosscutting issues are considered in this chapter: (1) the adequacy and balance of the PNGV program as a whole; (2) major achievements and technical barriers; (3) vehicle crashworthiness; (4) fuel strategy; (5) emissions trade-offs; (6) PNGV goals 1 and 2; and (7) government involvement and interfaces.

Adequacy and Balance of the PNGV Program

As in previous reviews, the committee finds it difficult to assess the allocation of resources for the PNGV program because no funding plan was made available. In several previous reports, the committee concluded that insufficient resources have been allocated to the program's activities considering the magnitude of the challenges facing the PNGV program to meet the objectives of Goal 3 (NRC, 1996, 1997, 1998a). Estimates of federal government appropriations for PNGV-related activities were about $263 million, $219 million, and $240 million for fiscal years 1997, 1998, and 1999, respectively (Patil, 1998) (see Table 4-1). These appropriations include work directly relevant to PNGV and coordinated with PNGV technical teams (Tier 1), work directly relevant to PNGV but not coordinated with PNGV technical teams (Tier 2), and work indirectly related to PNGV or supporting long-term research (Tier 3). Expenditures by industry for proprietary work are not known by the committee but are expected to be comparable (NRC, 1994). Visits by committee subgroups confirmed that substantial work on proprietary concept vehicles is under way.



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--> 4 Major Crosscutting Issues Several major crosscutting issues are considered in this chapter: (1) the adequacy and balance of the PNGV program as a whole; (2) major achievements and technical barriers; (3) vehicle crashworthiness; (4) fuel strategy; (5) emissions trade-offs; (6) PNGV goals 1 and 2; and (7) government involvement and interfaces. Adequacy and Balance of the PNGV Program As in previous reviews, the committee finds it difficult to assess the allocation of resources for the PNGV program because no funding plan was made available. In several previous reports, the committee concluded that insufficient resources have been allocated to the program's activities considering the magnitude of the challenges facing the PNGV program to meet the objectives of Goal 3 (NRC, 1996, 1997, 1998a). Estimates of federal government appropriations for PNGV-related activities were about $263 million, $219 million, and $240 million for fiscal years 1997, 1998, and 1999, respectively (Patil, 1998) (see Table 4-1). These appropriations include work directly relevant to PNGV and coordinated with PNGV technical teams (Tier 1), work directly relevant to PNGV but not coordinated with PNGV technical teams (Tier 2), and work indirectly related to PNGV or supporting long-term research (Tier 3). Expenditures by industry for proprietary work are not known by the committee but are expected to be comparable (NRC, 1994). Visits by committee subgroups confirmed that substantial work on proprietary concept vehicles is under way.

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--> TABLE 4-1 PNGV Total Government Budget Authority (in $ millions)   FY 97 FY 98 FY 99 Requesta FY 99 Agency Activity Appropriations Appropriations Tier 1 Tier 2 Tier 3 Appropriations DOE 123.1 122.7 153.6 0.0 5.0 134.0 EPA 15.0 15.6 35.0 0.0 0.0 29.0 DOT 12.5 4.5 3.5 0.0 0.0 2.5 DOC 56.0 29.0 0.5 15.0 6.8 25.3 NSF 56.0 47.0     52.0 49.0 Total without DOD 262.6 218.8 192.6 15.0 63.8 239.8 a ''Tier 1: work is directly relevant to PNGV and is coordinated with PNGV technical teams; Tier 2: work is directly relevant to PNGV but is not coordinated with PNGV technical teams; Tier 3: work is indirectly related to PNGV or is supporting long-term research. Acronyms: DOE = U.S. Department of Energy; DOT = U.S. Department of Transportation; DOC U.S. Department of Commerce; NSF = National Science Foundation; DOD = U.S. Department of Defense Source: Patil (1998). The committee is encouraged by several trends in the past year. First, since the technology-selection process at the end of 1997 winnowed down the number of technologies, the PNGV has been able to focus available resources on the most important areas. Second, the fiscal year 1999 budget for DOE's Office of Advanced Automotive Technologies includes moderate increases for some of the long-range technologies, like fuel cells, although the increases are far below the level needed to overcome the serious challenges facing these technologies.1 Third, the three USCAR partners have substantially increased their proprietary efforts towards the development of concept vehicles and have formed significant vehicle-development groups. Finally, the PNGV technical teams appear to be working well together. Despite these positive trends, however, the committee continues to believe that the program will require additional resources. Furthermore, other government agencies (e.g., EPA) and industries (e.g., petroleum companies and automotive component manufacturers) must be brought into the PNGV program. The committee believes the near-term and long-term technologies the PNGV has selected have the potential to meet the program's objectives. Some critics of the program have suggested that the CIDI engine should not be pursued for the U.S. market because of its particulate and NOx emissions. However, the 1   Development of advanced technologies within the DOE's Office of Advanced Automotive Technologies is central to government activities in support of the PNGV program. In addition, this office has long-range activities planned that support technology development to meet goals and objectives beyond 2004.

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--> committee believes that its potential fuel economy and high degree of technical maturity warrant its continued development, especially in light of the uncertainties facing fuel-cell technologies. Also, the PNGV should consider the CIDI engine for a non-hybrid vehicle. In the committee's fourth report, it was noted that the non-hybrid vehicle with a CIDI engine could provide a fuel economy of 65 mpg at significantly lower cost than the hybrid vehicle. The overall impact on vehicle-lifetime fuel economy over today's vehicle is very significant (NRC, 1998a). Extensive overseas markets in Europe and Asia for high fuel-economy vehicles offer an opportunity to improve fuel economy worldwide and reduce emissions. Overall, the committee concluded that, although the PNGV as a whole is substantially underfunded, the balance between short-term and long-term objectives is appropriate because measurable progress is being made in overcoming significant technical barriers. Major Achievements and Technical Barriers The PNGV program is structured to provide parallel efforts to develop vehicle systems and subsystems (which are necessary to meet vehicle-performance and fuel-economy targets), as well as in materials and manufacturing methods (which are necessary to meet cost and mass-manufacturing targets). These efforts combined have yielded significant progress towards meeting goals 1, 2, and 3 of the PNGV program. Nevertheless, major technical barriers remain to be resolved, especially for meeting Goal 3 (a production-ready vehicle by the year 2004). A fuel economy of 80 mpg (gasoline equivalent) for a family sedan, without sacrificing performance or utility, is being logically pursued through simultaneous efforts to reduce vehicle mass and increase the thermal efficiency of the drivetrain. The mass reductions are being pursued primarily through the substitution of aluminum and/or composites for much of the steel in present-generation vehicles. Increased (average) thermal efficiency is being pursued through more efficient energy converters (4SDI engines or fuel cells), probably in an HEV configuration. From the standpoint of meeting Goal 3, technical achievements, as well as maintaining or improving current performance in critical areas such as safety and emissions, are of primary importance. No matter how impressive the mass reductions and gains in efficiency are, they will have little long-term value until materials, processes, and manufacturing techniques have been developed for mass manufacturing and costs have been reduced. Therefore, technical achievements in the manufacturing-related areas will be just as important as achievements in the more visible areas of vehicle and component technologies.

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--> Achievements Reductions in Vehicle Mass Several advances in vehicle-mass reduction have been made in the past year. First, a lightweight, mostly composite and aluminum, hybrid vehicle-body structure was developed by the PNGV vehicle-engineering team and Multimatics. Computer simulations showed a structural performance that meets or exceeds the performance of a baseline steel vehicle, with a weight reduction of more than 68 percent. Major changes in the fabrication of the new structure are being addressed in an effort to reduce fabrication costs. Second, electromagnetic forming was demonstrated by the PNGV materials team, along with USAMP and Ohio State University, for forming aluminum hoods and door panels. Third, work is continuing to improve lightweight honeycomb materials while reducing costs. Fourth, studies on lightweight interior materials indicate a possible 40 percent mass reduction with little or no cost or comfort penalties. Finally, work in conjunction with suppliers continues for the elimination of a spare tire through the development of a "run flat" (low rolling resistance) tire. 4SDI Engines As noted in Chapter 2, 4SDI engines are already capable of providing thermal efficiencies approaching 40 percent, at or near optimum speed and power-output operating conditions. With a hybrid configuration, much more of the operation would be near the optimum conditions, and a reservoir for storing recovered braking energy would be provided. However, emissions of NOx and particulates are major obstacles to meeting existing and expected emissions regulations. For these reasons, the successful implementation of a 4SDI engine into vehicles for the PNGV program depends on a hybrid configuration and reductions in emissions. Some achievements in reducing emissions are listed below: A precise, repeatable "micropilot injection" fuel-injection system was developed by the PNGV 4SDI team with EPA and FEV. An auto-sized lean-NOx catalyst removed more than 30 percent of the NOx from the exhaust of a CIDI engine burning low-sulfur fuel. The PNGV 4SDI technical team, ORNL, and SNL were involved. A new fuel was blended and tested by the PNGV 4SDI technical team, SWRI, and DOE, which reduced particulate emissions by 50 percent as compared to standard diesel fuel. Fuel Cells Several important accomplishments were made in the past year. A rapid-start (two minutes) gasoline fuel processor was demonstrated by the PNGV fuel-cell

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--> technical team with GM and ANL. A brass-board automotive-scale CO cleanup system for a gasoline fuel processor was demonstrated by the PNGV fuel-cell technical team with LANL. A gasoline fuel processor, CO cleanup system, and small PEM stack were operated together by the PNGV fuel-cell technical team, ADL, and LANL. A complete 30-kW methanol-fueled fuel-cell brass-board engine was successfully operated by the PNGV fuel-cell technical team with GM. Hybrid System Components Various improvements in hybrid electric vehicle components were made in the last year. Traction motor specifications for both parallel and series hybrids were developed by the PNGV EE technical team. Twelve amp-hr lithium-ion battery cells were demonstrated in cycle testing and first-generation 50-V modules were constructed by the PNGV battery technical team with SAFT. A first-generation nickel metal hydride 50-V battery module is in a test program with the PNGV battery technical team and VARTA. Systems-Analysis Tools Although analysis tools are in a different category from the hardware discussed above, they are absolutely essential for matching components and operating strategies to maximize performance and efficiency. Several achievements in this area have been made. A computer model for fuel economy and optimizing control of hybrid systems was demonstrated by the PNGV systems-analysis team with TASC and SWRI. A fuel-cell system-simulation model was developed by ANL and the PNGV systems-analysis team and conveyed to users. Energy Reduction for Vehicle Accessories Heating and cooling loads have been reduced through a combination of focusing on passenger comfort, leveraging commercial technologies, improving cabin thermal integrity, reducing thermal mass, and improving recirculation systems. A number of technologies are being used to increase the energy efficiency of heating/cooling devices, including variable-speed scroll compressors, microchannel heat exchangers, energy-storage devices, heat recovery from electronic devices, and advanced control systems. Manufacturing Processes Achievements in this area can be divided into two categories: (1) achievements related to manufacturing vehicles and (2) achievements related to manufacturing specific components. Significant progress was made in both areas.

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--> Methods for light-metal castings optimized by a materials database, on-line sensors, and modeling were developed by the PNGV materials technical team with USAMP, SNL, LLNL, and ORNL. A high-volume programmed powder preform process (P-4) for composites was demonstrated by the PNGV materials technical team with the USCAR Automotive Composites Consortium and Owens Corning. Coatings and design modifications to improve high-speed drilling were made by the PNGV manufacturing technical team. Compression-molded composite bipolar plates for fuel cells to replace machined graphite plates were successfully demonstrated by the PNGV fuel-cell technical team with IGT. A continuous process for manufacturing fuel-cell MEAs to replace individual lay-ups was demonstrated by the PNGV fuel-cell technical team with the 3M Company. Summary In the past year, more progress has been made towards meeting PNGV goals than in any previous year. Undoubtedly, this is partly because progress in R&D is cumulative. However, the committee believes that much of the progress can also be attributed to the attitude and efforts of the PNGV technical teams who are now working with more team spirit toward meeting common goals. The committee believes this is a very positive change that has provided a needed boost to continuing technical productivity. Technical Barriers Even though significant achievements have been made in many technical and manufacturing areas, many critical issues are still unresolved. These include issues related to the engine and vehicle, as well as manufacturing issues. The most significant issues are described below. Engine and Vehicle In spite of reductions of NOx and particulates in 4SDI engines, there is still a long way to go to reach acceptable emissions levels with acceptable technologies. The "fuel-flexible" fuel processor for fuel-cell energy converters is still in the laboratory/brass-board stage, and no convincing evidence has been found that this is the best path to follow (as opposed to processors tailored for specific fuels). Currently, technical solutions must be found for the compressor/expander components, which are essential to a multi-atmosphere pressurized fuel-cell stack. Little effort has been made to identify "optimum" fuel properties for either 4SDI or fuel-cell energy converters. Lithium-ion batteries appear to be almost essential for an acceptable hybrid system, but no solution has been found to the critical issue of thermal

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--> management; a reformulation of the basic chemistry might be necessary to meet life-cycle targets. To meet the goals for mass reduction, significant changes must be made to the 4SDI engine, chassis, power train, and virtually all of the electric-drive components. Further work will be necessary on air conditioning, power steering, and other accessories to approach the mass of a production vehicle and to meet manufacturability requirements. Overall system efficiency and optimum control strategy are primary concerns for "fuel-flexible" fuel cells. In fact, no complete system has yet been operated on gasoline. Manufacturing Processes A number of potential barriers have already been identified, and many more will certainly surface as the program moves closer to the production prototype phase. The barriers identified so far primarily relate to mass manufacturing at acceptable costs. Lamination materials and processing for electric rotors and stators must be developed. Supplies of aluminum sheet, magnesium, and carbon fiber must be available at acceptable costs. Processes for manufacturing power electronics and electronic components, as well as high-pressure common-rail fuel-injection systems, will have to be developed. Fabrication processes will have to be improved for lithium-ion cells and batteries. Production processes will have to be developed or improved for virtually all major components and subsystems for fuel cells. Summary For the most part, PNGV's technical efforts have been appropriately directed, and significant technical achievements have been made. However, with a few exceptions, these achievements represent progress rather than solutions. For the near-term 4SDI vehicle, additional emission reductions at affordable costs will be necessary. In addition, a lower cost supply of base materials for the manufacture of reduced-mass body/chassis assemblies must be found and mass-manufacturing processes developed. Additional mass reductions in the engine/drivetrain and other components will also be necessary. The successful demonstration of the composite bipolar plates and a continuous process for membrane-electrode assemblies have gone a long way towards achieving the cost goals for fuel-cell stacks. However, the multifuel fuel processor and CO cleanup system are still in the early laboratory development stages, and potential manufacturing and materials problems have only begun to be identified. The compressor/expander systems are at an intermediate stage of development, but final products and manufacturing problems cannot be identified yet. A successful HEV configuration for either the 4SDI engine or fuel cell will depend on motor and power-electronic technologies that are reasonably well defined; mass-manufacturing techniques have not been defined, however. The

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--> hybrid system will also depend heavily on a robust, lightweight, low-cost battery. The lithium-ion battery seems to be an excellent candidate but is far from a complete system with mass-manufacturing capabilities. Vehicle Crashworthiness PGNV concept cars must be as safe or safer than baseline vehicles. Given that many new technologies will be introduced simultaneously, this could be a difficult task. For every new technology, new failure modes and safety concerns will have to be assessed, including crashworthiness, flammability, explosion, electrical shock, and toxicity. The committee has not reviewed safety issues in depth with the PNGV technical teams but is satisfied that they are aware of these issues and are addressing them on an ongoing basis as part of the overall program. Vehicle crashworthiness, for example, will be clarified when concept vehicles are being built. Failure modes for all promising technologies are being investigated; the safety concerns associated with handling and storing onboard hydrogen for fuel-cell powered vehicles are being examined; and computer simulations are being used to evaluate the crash performance of HEVs. Among the new technologies under consideration by the PNGV are lightweight structural materials, HEV power plants (including fuel cells), new fuels (including hydrogen), energy-storage devices (including lithium-ion batteries), and new glazing materials. Vehicle-Fleet Issues The PNGV concept vehicle will have to weigh about 2,000 lbs, 1,200 lbs less than the baseline vehicle. Moreover, the PNGV weight-reduction targets cannot be met by downsizing the vehicle but will require using lightweight materials and more efficient designs. The question arises as to how these lightweight vehicles, in a population of much heavier vehicles, will fare in car-to-car collisions. It has been well documented that when vehicles are downsized to reduce weight, occupant safety is reduced (DOT, 1997). If the concept vehicles developed in the PNGV program are not downsized, however, the crush space for frontal, side, and rear impacts would be comparable to that of today's vehicles, and, therefore, this may not be as big an issue as was first thought. Crash-Energy Management Based on a simple application of Newton's second law (force = mass × acceleration), lower mass vehicles do experience higher decelerations in barrier crashes, assuming that heavy and light vehicles have the same crush force (or resisting force). In fact, current design practices, which are based on barrier crash

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--> requirements, have used low-stiffness front ends to ensure that decelerations are in the range of 15g to 25g. It has been pointed out, however, that barrier crashes represent crashes of mirror images and do not represent car-to-car collisions (Frei et al., 1997). If a lightweight, full-sized vehicle, such as the PNGV Goal 3 vehicle, were designed with current design practices, it would be at a disadvantage in crashes with heavier cars because the soft front end would cause most of the crash energy to be absorbed by the lighter car while significant deformation of the heavier car had barely begun. To ensure compatibility in car-to-car collisions, it has been argued that light and heavy cars should crush at the same load level, which implies that the deceleration of the lighter car would have to be larger than for the heavier car by the ratio of the mass of the heavy car to the lighter car (Frei et al., 1997). The resisting force of the lighter car structure could be designed so that the deceleration does not exceed a safe level of 40g to 50g. Another implication of this approach is that the crush distance of each vehicle would be proportional to the mass of the vehicle. The crush zone of the lighter car would have to be long enough to absorb at least its own kinetic energy. These assumptions have been confirmed in car-to-car crash tests (Frei et al., 1997; Niederer, 1993). Hence, vehicles in the PNGV program should be, and are being, designed to provide adequate crash-energy absorption and crush distance. Crashworthiness of Alternate Materials It is useful to compare the crash-energy absorption characteristics of the alternate materials under consideration by PNGV, particularly aluminum and CFRP. The crash-energy characteristics of an Al 6061-T6 dual-tube rail exhibits the same progressive folding behavior as steel (Haddad et al., 1989). CFRP square tubes, however, show a much finer oscillation associated with the tube failing by progressive delamination and pulverization, as well as splitting at the corners and peeling back of the sides, much like a banana skin peels. Although the crush behavior is different, an experimental comparison of the specific energy absorption of steel, aluminum, and CFRP square tubes shows that aluminum and CFRP can match the energy absorption of steel and still save weight (see Table 4-2). Based on these test results, the committee believes that structural concepts and analytical tools are available to design lightweight PNGV concept cars that will perform safely in collisions with heavier cars because of the excellent energy absorption characteristics of the alternate materials. Nevertheless, the committee recognizes that vehicle safety research is in its infancy and believes the National Highway Traffic Safety Administration should become involved in crashworthiness studies of lightweight vehicles with designs comparable to the designs of PNGV vehicles.

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--> TABLE 4-2 Comparisons of Square-Tube Axial Energy Absorbersa Materials Weight Savings Relative to the Baseline Material Steel 1015 baseline material HSLA 950 14% Aluminum 6061-T6 52% 5052-O 43% CFRP 91% a It is assumed that the square tubes experience equal deflection in bending and equal crush load. HSLA is high-strength low-alloy steel. Source: Magee and Thornton (1978). Recommendation Recommendation. The PNGV and USCAR partners should continue to make vehicle crashworthiness a high priority as they move toward realization of the concept vehicles. Fuel Strategy Importance of Fuel Considerations The PNGV program is predicated on the assumption that the widespread deployment and use of higher fuel-economy vehicles will provide significant societal benefits. These benefits include the reduction of potentially harmful emissions to the atmosphere, reduced dependence on petroleum imports, and the consequent improvement in the U.S. balance of payments. If, in order to achieve these benefits, significant changes in fuel composition or the manner in which automotive fuel is distributed are required, then the impact of these changes should be an integral part of the program. As the committee noted in its fourth report, significant changes in automobile power plants can have wide-ranging effects on the fuels industry (NRC, 1998a). Changed fuel characteristics may make modifications to power plants possible that would otherwise be impossible. The most promising power plants being considered by PNGV, namely, CIDI engines and fuel cells, may require extensively modified fuels. However, even if the PNGV program can achieve Goal 3 by using one of these power plants, the possibility of marketing the vehicles may be limited, or even prohibited, by the unavailability of suitable fuels. Therefore, it is vitally important that the PNGV pursue the development of appropriate fuels concurrently with the vehicle program. In addition, the PNGV must be aware of the business and economic viability of fuel changes and anticipate any environmental and energy-consumption consequences that may result from their widespread use in automobiles.

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--> The automotive fuels industry, including both production and distribution, is a capital intensive industry that requires a long lead-time to effect major changes. Changes in fuel composition can have different impacts on different companies depending on their refining processes, sources of crude petroleum, product mix, and other factors. These factors add to the difficulty of rapid, widespread distribution of modified fuels and should be addressed explicitly by the PNGV. Status of Fuel Considerations within the PNGV The PNGV recognizes the importance of modified fuel in achieving emission targets for CIDI engines and is testing various fuels. Ad hoc pairings of fuel companies and auto manufacturers have developed test programs to evaluate the effects of various fuel modifications on emissions, as well as on after-treatment catalysts. Results so far have shown that lower sulfur content in petroleum fuels reduces particulate emissions and extends catalyst life. In the short term, low-sulfur fuel would enable gasoline engines to meet more stringent emission requirements; in the midterm, it would be critical to the introduction of CIDI engines; and in the long term, it would be necessary for vehicles with fuel cells using petroleum-based fuels and reformers. The DOE has taken a leadership role on this issue. Some working groups have been formed, and ANL is assessing fuels-infrastructure issues, including capital-cost projections and assessments of the energy and environmental effects of potential fuel and power-plant changes as vehicles that meet Goal 3 are introduced (Wang et al., 1998). These projections would be greatly improved with critical input from the major petroleum companies that would be involved in implementing the changes. Input by petroleum companies would validate or reject the assumptions underlying these projections and ensure that they are based on accurate, real-world business considerations. The EPA is also involved in decisions about fuels. EPA is aware that if exhaust emission standards are too stringent in the near term, the most fuel-efficient power plants could be precluded or could require a fuel that could not be made available economically or in time to meet PNGV goals. Overall, the PNGV is now paying more attention to fuel issues, although no mechanism has been established at the policy level to address the fundamental trade-offs between vehicle exhaust emissions and energy efficiency. Long-range strategic issues have not been addressed effectively by the fuels industry or the automobile manufacturers. Recommendation Recommendation. A comprehensive mechanism should be established to help define feasible, timely, compatible fuel and power-plant modifications to meet the PNGV goals. This mechanism will require extensive cooperation among

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--> automotive and fuels industry participants at all levels of responsibility, but also among technical and policy members of relevant government organizations. Emissions Trade-Offs The emissions-control potential of the power train in the context of the total vehicle is a critical performance issue. California and the EPA in their LEV-2 and Tier II standards, respectively, have extremely stringent light-duty vehicle requirements for NOx and particulate emissions. Although the engine is the most important vehicle subsystem in terms of emissions, the power-train configuration (hybrid or direct mechanical drive), energy-storage system, total-vehicle weight, and especially fuel composition can all affect emissions control significantly. The most critical component of the total system is the exhaust-gas treatment technology (the catalyst, particulate trap, exhaust-gas sensors, and controls) used to reduce the engine-out emission levels substantially before the exhaust is released to the atmosphere. The capability of the CIDI engine to meet future emissions requirements is uncertain. Engine-emissions controls (e.g., high-pressure fuel injection, retarded injection timing, intake air-temperature control, and exhaust-gas recirculation) are also incapable of meeting these requirements; and a fuel economy penalty of 5 to 10 percent is incurred through use of engine-emissions controls. Catalyst technology with the CIDI engine has shown promise of achieving significant reductions for NOx but is still in the exploratory development stage. Particulate-trap technology, despite efforts over the past two decades, is at a similar stage of development. Because there are trade-offs between NOx emissions, particulate emissions, and fuel economy when emissions control is used with the CIDI engine, effective exhaust-treatment systems for NOx and particulates will be vitally important to achieving PNGV emissions, fuel economy, and cost targets with this engine. The effectiveness of exhaust-treatment technology for CIDI engines is greatly affected by fuel composition. Sulfur levels in the fuel significantly influence the efficiency and durability of catalyst technologies, as well as particulate mass emissions. Other factors that influence particulate emissions are aromatic content, cetane number, volatility, and oxygenate components blended with the fuel. The GDI engine, which is considered the best short-term backup technology to the CIDI engine, also has problems with engine and exhaust-treatment emissions technology, including trade-offs with fuel economy in the engine, the cost and effectiveness of the exhaust catalyst system, unresolved questions about particulate emissions, and fuel-composition requirements (especially sulfur levels). However, the GDI's potential for meeting California LEV-2 and EPA Tier II requirements is significantly better than that of the CIDI engine. Like the CIDI engine, the GDI engine operates with lean fuel-air mixtures at part load to improve efficiency. The GDI, however, can also operate with

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--> stoichiometric and rich fuel-air mixtures; under these conditions, an alternative NOx storage catalyst technology could be used that appears promising and is being developed. With this catalyst technology, NO is oxidized to NO2 and stored on the catalyst as nitrate under lean engine operating conditions; the nitrate is decomposed and then reduced when the engine is run slightly rich for a short period (incurring a modest fuel-economy penalty). The GDI engine and this catalyst technology are currently in limited production, and extensive efforts are under way worldwide to develop them further. The committee continues to believe that the PNGV program should monitor the performance (fuel economy, emissions, cost) potential of this technology for the U.S. market and compare the operating characteristics of a GDI engine hybrid with those of the CIDI engine hybrid. Fuel-cell technology also has unresolved emissions-control issues. When used with a gasoline or methanol reformer on board the vehicle, there is a potential for emissions from the reformer, especially during transient operation. The limited data available to date indicate that emissions during steady-state operations can be kept extremely low, but no data are available for transient operating conditions. Fuel sulfur levels must also be very low. The PNGV systems model (see Chapter 3) is an important tool for evaluating the emissions, fuel economy, performance, and cost trade-offs for promising combinations of power-train and vehicle technologies and for optimizing the total vehicle design. The model should not only address the fuels characteristics that affect emissions, but should also assess the energy consumption and emissions from fuel production and distribution. Before the systems model can be used with confidence to assess vehicle emissions, fuel economy, and performance trade-offs, it must be validated against emissions and other performance data. Validation studies will probably identify areas where additional submodel development is required. The committee recommends that validation and improvement of the emissions components of the systems model be given a higher priority during the next year of the PNGV program. Based on presentations made by the PNGV (government and industry members), the committee believes the interdependency of power trains (4SDI engine or fuel cells), fuel economy, and emissions is not being adequately addressed. The current California regulatory proposals on NOx and particulate emissions are likely to preclude the use of the very efficient CIDI engine in the United States unless an effective exhaust-gas treatment technology can be developed, the prospects for which depend on the extent and rate of implementation of improvements in diesel fuel. These standards may thus inhibit increased fuel economy and reduced petroleum consumption for the nation as a whole. To date, the government agencies involved in the PNGV responsible for these issues have pursued agency objectives without taking into account the interdependency of these issues. The committee considers that the PNGV program is uniquely situated to examine these critical interdependencies and recommends that the PNGV

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--> management develop and implement coordinating policies. Given the limited choices for technologies that can meet the PNGV goals, the PNGV should establish a clear policy on fuel standards, emission regulations, and fuel economy and cost expectations. Recommendation Recommendation. The federal government agencies involved in the PNGV program should review how future emissions requirements (especially NOx and particulates), fuel economy, CO2 emissions, as well as fuel quality, will affect the choice of the CIDI engine as the most promising short-term combustion-engine technology; a program plan that responds to that assessment should be developed. The PNGV, especially the U.S. Department of Energy and the Environmental Protection Agency, should work closely with the California Air Resources Board on these issues. Once the systems model has been validated, it would be an appropriate tool to use in quantifying the necessary trade-offs. Goals 1 and 2 Goal 1 is to significantly improve national competitiveness in manufacturing for future generations of vehicles through upgrades in manufacturing technology incorporating agile and flexible processes, reductions in costs and lead times, reductions in environmental impacts, and improvements in product quality. Goal 2 is to implement commercially viable innovations from ongoing research on conventional vehicles through improvements in fuel efficiency and reductions in emissions on standard vehicles, advances in safety designs, and reductions in energy demands of the engine and drivetrain. Goals 1 and 2 are open-ended and have no quantitative targets or milestones. Because the Goal 3 concept demonstration vehicles are focusing on relatively near-term technologies, the distinction between goals 1, 2, and 3 has become blurred. Some improvements in manufacturing processes related to technology development for Goal 3 are discussed in the appropriate technology sections in this report. Goal 1 The PNGV has identified the following key challenges to the manufacturing system: (1) the development of high-volume manufacturing processes, (2) the development of cost-effective tooling and equipment, (3) ensuring ample supplies of low-cost lightweight materials, (4) reducing cycle times, and (5) providing a viable supply base for new technologies. The committee reviewed the following Goal 1 projects that were initiated previously to assess their progress (background on these projects can be found in the committee's third report [NRC, 1997]):

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--> Spring-back predictability. Completion is expected by the end of 1999. A major remaining task is software development. Intelligent resistance welding. Completion is expected by the end of 1999. A major remaining task is the development of algorithms and controls for closed-loop operation. High-throughput hole making. Completion is expected by the end of 1999. An important remaining task is the testing of production prototypes. Leak-test technology. Completion is expected by the end of 1999. Prototype development is a remaining task. Dry-machining of aluminum. Completion is expected in early 2001. Materials development is still necessary. Aluminum die casting. Initial program plans and validation of concept have been completed. Testing on full-sized development prototypes will be conducted in collaboration with suppliers. Laser-welding of aluminum. The structural alloy portion has been completed. Feature-based modeling. Project has been cancelled. Ergonomics for hand tools. Project has been cancelled. Powder paint. This is no longer a PNGV project but is now a separate industry consortium in USCAR. New project initiatives include (1) stamping die materials and foundry practices, (2) developing reliable robust components in manufacturing, and (3) developing an integrated arc-welding cell. Plans The PNGV is also reviewing potential projects in (1) hydroforming development, (2) rapid prototyping, (3) nondestructive evaluation concepts, (4) magnesium processing, and (5) expansion of R&D on high-throughput hole making. The PNGV also plans to support the manufacturability assessments by the PNGV technical teams in other areas, as requested, review project portfolios of other automotive-related organizations for their relevancy to the PNGV, communicate project findings to manufacturing management of the USCAR partners, and initiate production application of projects. Concerns A growing number of PNGV Goal 1 projects are proprietary, especially as the technologies relate to the concept vehicle systems being developed by the USCAR partners. Consequently, it is becoming increasingly difficult for the

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--> committee to assess the PNGV's progress because target values for processes and systems are not being openly reported. However, because goals 1 and 2 are open-ended, there is no easily defined metric for measuring progress in any case. Recommendation Recommendation. Future committee reviews should focus on the progress of manufacturing projects toward meeting the needs of the Goal 3 technical teams in development of component and subsystem technologies. Goal 2 The USCAR partners have been continuously adding innovative components and subsystems to conventional vehicles. For example, Ford Motor Company, in addition to numerous weight saving measures on 1997–1998 model year cars and trucks, is producing 1998 alternative and flexible-fuel vehicles to meet a variety of standards for low-emission vehicles (LEVs), super ultralow emission vehicles (SULEVs), and zero-emission vehicles (ZEVs). Ford also plans to produce light trucks with conventional gasoline engines at the LEV standard in the 1999 model year. In the past five years, GM has produced some innovative aluminum structures in Corvette vehicles. In addition, GM is incorporating lessons learned from its EV-1 electric vehicle, which has been in production for several years, into its PNGV concept-vehicle system. DaimlerChrysler has used its low-volume production Prowler and Viper vehicles to gain experience with aluminum and composite materials. Plans Although no specific plans have been announced, the USCAR partners are expected to continue trying out new components, subsystems, and materials on low-volume niche-market vehicles. Concerns The committee's assessments of progress with respect to Goal 2 will continue to be after-the-fact because the committee cannot monitor progress on a real-time basis. Recommendation Recommendation. Future reviews of the PNGV program should not include evaluations of progress towards Goal 2. Instead, the three USCAR partners should make nonproprietary information available to the public.

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--> Government Involvement and Interfaces A program like the PNGV that involves the intermingling of government and private-sector funds, as well as personnel, will always raise questions about the methods and extent of appropriate government participation. The committee has always held the view that the PNGV, as a whole, is a program of national importance because developments on advanced vehicles would not be pursued in response to market forces at this time. Therefore, government funding and participation are entirely appropriate. The committee has previously recommended that government participation be primarily directed towards high-risk, but potentially high-payoff, technologies. In essence, it is in the national interest that technologies be available to produce fuel-efficient vehicles with low emissions, even (and especially) if there is little market demand for them. The absence of market demand means the private sector would have little incentive to make the necessary huge investments in technology developments. The same logic applies to the development of manufacturing processes to make American manufacturing more globally competitive. R&D on advanced generic materials and processes are more feasible through industry/government cooperation than for individual companies. Some technologies, such as the CIDI engine, are being developed by private industry, but for vehicles much less demanding than the PNGV vehicle. General emission, particulate emission, and noise requirements for military and industrial CIDI engines are much less stringent than they are for the PNGV vehicle. Combined with the relatively low production volumes expected for CIDI engines in the near term, individual companies would not be able to justify investing in R&D to meet PNGV targets. Thus, government participation in areas such as combustion chambers, injection systems, exhaust after-treatments, and even new fuels can be easily justified. Some technologies have long-term potential, but only if one or more major obstacles can be overcome. The gas-turbine engine, for example, promises to be a small, lightweight, low-emission engine, but requires very high turbine temperatures and expensive turbomachinery. Further government involvement in the development of gas-turbine engines is probably not justified until low-cost, high-temperature (presumably) ceramic turbines become a possibility. The committee considers the development of a ceramic turbine material an enabling technology that does justify government support (NRC, 1997, 1998b). A similar case can be made for resolving the containment issue for flywheels. Fuel cells are in a different category because they have great long-term potential for meeting PNGV goals, and many of the major problems are generic; continued major government investment in these technologies can clearly be justified. Government support for R&D related to the PNGV is provided by several federal agencies (see Table 4-1). Work directly relevant to PNGV and coordinated with PNGV technical teams is supported by DOE's OAAT. In fiscal year

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--> 1999, OAAT's expenditure comes to about $129 million, or 54 percent of the federal monies estimated to be supporting the PNGV program, either directly or indirectly. Total federal appropriations for fiscal year 1999, either directly relevant to the PNGV and coordinated with the PNGV technical teams (Tier 1), directly relevant to the PNGV but not coordinated with the technical teams (Tier 2), or indirectly related to PNGV or supporting long-term research (Tier 3) is about $240 million (Patil, 1998). PNGV research supported by OAAT (most of OAAT's activities) includes work on vehicle systems, fuel cells, batteries, advanced combustion engines, alternative fuels, and automotive materials technology. OAAT also has programs that are not part of PNGV, such as the development of electric-vehicle technology. At current funding levels, OAAT cannot expand its R&D beyond the PNGV technologies selected in January of 1998. Based on OAAT's R&D plan for technology development beyond 2004, OAAT believes that government funding should extend beyond PNGV's time horizon of 2004 (DOE, 1998). Work directly relevant to the PNGV program but not coordinated with the PNGV technical teams is also supported by the National Institute for Standards and Technology, both through in-house activities and the Advanced Technology Program. The total level of funding was $19 million in fiscal year 1999. Activities by the Advanced Technology Program directly relevant to the PNGV program are R&D on lightweight materials, energy storage and conversion, advanced manufacturing, and individual projects on reducing mechanical losses, controlling emissions, developing alternative fuels, and improving crashworthiness. Both the National Science Foundation, and to a lesser extent the Office of Science (formerly the Office of Energy Research) at DOE, support research indirectly related to the long-term goals of PNGV. In fiscal year 1998, the National Science Foundation funding was $47 million, and DOE Office of Science funding was $5 million. Considerable talent and R&D is also being provided by the national laboratories through DOE funding. About half of the research supported by the National Science Foundation is conducted at engineering research centers; the balance is carried out by individual principal investigators. A very small fraction of the work is conducted at corporate laboratories through the Small Business Innovative Research program. The U.S. Department of Transportation, the U.S. Department of Defense, the National Aeronautics and Space Administration, and EPA also have various projects that support or supplement PNGV activities. Since the DOE OAAT is the principal source of federal support for the PNGV program, it is important that OAAT's program be properly focused. In a recent National Research Council review of the OAAT R&D program plan, OAAT was advised to fund only generic, precompetitive R&D that industry would not otherwise support (NRC, 1998b). An example of this type of research is the development of low-cost, high-performance fuel cells, fuel-cell stacks, and fuel reformers for liquid fuels (e.g., methanol to hydrogen). Fuel-cell systems

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--> continue to be the most attractive long-term source of power for automobiles of the future, but significant improvements in performance and cost for currently available technology must be made. As part of supporting R&D related to the PNGV program, the OAAT must validate technologies developed with federal funding. To avoid competition with industry; OAAT has agreed to limit its validations to components and component systems, leaving the validation of systems performance in concept vehicles to industry. OAAT also conducts tests of systems models. The committee suggests that the criteria used by OAAT for validation be defined in close partnership with industry. The priorities for component and systems performance, and the degree to which trade-offs in performance demands can be made, should also be established with input from industry. Government funds, line items or not, supporting PNGV are provided by a considerable number of departments and laboratories. Given the difficulties of achieving effective coordination among many different government agencies, the committee believes the program office at the U.S. Department of Commerce is doing a commendable job of promoting the interests of PNGV among government organizations and providing workable interfaces in its proactive support of the program. Recommendations Recommendation. The U.S. Department of Energy Office of Advanced Automotive Technologies should continue to focus its support on generic, precompetitive research and development that industry would not undertake on its own. Recommendation. The criteria used by the U.S. Department of Energy Office of Advanced Automotive Technologies to validate components and component systems should be established with the full cooperation and participation of industry.