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November 29, 2000
Mr. Craig Marks Chair,
Standing Committee to Review the Research Program of PNGV
National Research Council
2101 Constitution Avenue, N.W.
Room # HA 270
Washington, DC 20418
We want to thank you and the other Standing Committee members for your insightful and productive review of the Partnership for a New Generation of Vehicles.
Attached are our comments on the major recommendations from the 6th report. We agreed with many of your recommendations and we will be ready to discuss these with you at the upcoming 7th Review.
You also made a number of recommendations concerning the individual technology areas. The PNGV Technical Teams will address those areas during their discussions with you at the upcoming 7th Review.
Again we appreciate receiving your valuable analysis as we progress through the challenges of developing the PNGV technologies and advancing toward our goals.
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U.S. Department of Commerce
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Response to the NRC's 6th Peer Review Report Recommendations
1) RECOMMENDATION: PNGV should quantify the trade-off between efficiency and emissions for the power plants under consideration. The PNGV systems-analysis team should attempt to develop and validate vehicle emissions models of sufficient sophistication to provide useful predictions of the emissions potential for a variety of engines (e.g., the compression-ignition direct-injection engine, the gasoline direct-injection engine) and exhaust gas after-treatment systems in various hybrid vehicle configurations. The models could be used to help PNGV evaluate the feasibility of meeting the Environmental Protection Agency's Tier 2 emissions standards with various vehicle system configurations. These data should then be used to establish an appropriate plan for the next phase of the program.
RESPONSE: While such a modeling effort could be useful, we are unaware of any existing models that accurately predict emissions for multi-cylinder engines based on physical and chemical parameter inputs. Developing such a model would be a major undertaking with little guarantee of success.
2) RECOMMENDATION: At this stage, PNGV should direct its program toward an appropriate compromise between fuel economy and cost using the best available technology to ensure that a market-acceptable production-prototype vehicle can be achieved by 2004 that meets Tier 2 emission standards.
RESPONSE: Cost issues will be discussed during the Peer Review, Dec. 7–8, 2000.
3) RECOMMENDATION: Given the potential of fuel-cell technology for meeting the efficiency and emissions objectives of the PNGV program, the systems-analysis team should increase its efforts to develop more complete and accurate fuel-cell system and component models to support the development and assessment of fuel-cell technology.
1.) Both ADVISOR and PSAT simulation tools have been connected to GCTool (a detailed modeling and simulation tool for fuel cell system). GCtool is used to update the model and the data in both ADVISOR and PSAT.
2.) By working with Virginia Tech. University, the fuel cell future car has been used to validate ADVISOR model.
3.) A study of the effect of degree of hybridization on fuel economy for a fuel cell vehicle is in process.
4.) More detailed validation of the fuel cell model, that includes transients and warmup effects, is in process with Virginia Tech.
4) RECOMMENDATION: In the area of fuel cell development, PNGV, and especially the U.S. Department of Energy, should emphasize high-risk, high-payoff research in critical areas, such as fuel processing, carbon monoxide-tolerant electrodes, and air-management systems.
RESPONSE: We concur with Recommendation #4. The Department of Energy program is focused on the critical barriers addressed above, as well as other critical areas such as cathode improvements to increase cell voltage and stack efficiency, and high temperature membranes that will facilitate heat rejection and improve CO tolerance. In fuel processing R & D, the focus is on lowering the thermal mass to improve start-up time and efficiency, and on durable, high activity, shift catalysts to reduce the size, weight, and cost of the fuel processor. Los Alamos is continuing to work on CO-tolerant anodes. In the air management area, a peer review of compressor/expander technology was conducted during 2000. Recommendations to reevaluate PNGV air compressor technical requirements, and to downselect to focus on the most promising compressor technology, will be implemented in 2000 and 2001, respectively.
5) RECOMMENDATION: PNGV should continue to work on cell chemistry of lithium battery systems to extend life and improve safety, while continuing to lower costs. Performance and cost targets should be refined as overall vehicle systems analysis determines the optimal degree of vehicle hybridization.
RESPONSE: As recommended by the Committee, lithium battery chemistry development aimed at extending life, improving safety and reducing cost, is continuing. The PNGV battery cost and performance targets have been refined periodically, based on (informal) direction from the proprietary vehicle development efforts. PNGV is considering the development of collaborative vehicle-level cost, performance, and fuel economy models. It may be possible to determine more optimal hybrid vehicle configurations from such models, and the battery performance and cost targets could then be further refined.
6) RECOMMENDATION: As the PNGV program moves toward the 2004 production-prototype milestone, affordability will be a key requirement. Therefore, the development of an efficiently designed and fabricated steel-intensive vehicle being worked on by the American Iron and Steel Institute in Ultralight Steel Autobody-Advanced Vehicle Concept (ULSAB-AVC) project should be closely followed, and the possibility of applying the ULSAB concepts to a hybrid steel-aluminum vehicle should be explored.
RESPONSE: The Materials Team (as well as the Vehicle Engineering and Manufacturing Teams) continue to monitor the progress of the AISI ULSAB-AVC and related projects. The MTT arranged for representatives of AISI to meet with MTT, VE, and Mfg. Team representatives on May 25 to review the status and plans for the
ULSAB-AVC program, and the results and findings of the ULSAC (Ultra-Light Steel Auto Closures) program. At that time, PNGV TEAM members offered feedback and suggestions to make the studies more pertinent/applicable to PNGV. It was agreed that PNGV would not be directly involved in the AISI programs, but AISI would continue to provide periodic updates to pertinent PNGV teams.
The MTT is also working with the Auto-Steel Partnership, in conjunction with USAMP, in formulating high strength steel projects (which build on the results of ULSAB projects) for possible inclusion in the portfolio of projects funded by DOE's OTT Lightweight Materials budget (possibly through USAMP/DOE Cooperative Agreement).
Implementation of lightweight steel techniques and technologies is primarily a function of the individual OEMs. There are no plans to jointly build a hybrid steel-aluminum vehicle. However, the MTT is supporting DOE funding of projects to be proposed by a recently formed USAMP Joining Task Force, which was specifically chartered to identify and address issues surrounding joining a mixture of low mass materials, such as high strength steels, aluminum, polymer composites, and magnesium.
7) RECOMMENDATION: The committee recognizes the cost reduction potential of DaimlerChrysler's thermoplastic composite injection-molding technology and urges that this work be continued to bring the technology to successful commercialization. The committee encourages the earliest possible generation of vehicle and component test data to define better the structural properties and performance of various composite materials and structures.
RESPONSE: The thermoplastic body development underway at DaimlerChrysler is proprietary to them. It will be deployed, when ready, in their products. The first announced product is the Jeep Wrangler hardtop scheduled for production in the Fall of 2001.
8) RECOMMENDATION: The committee regards structural crashworthiness, and safety in general, in the design of lightweight PNGV vehicles as extremely important. Using the Oak Ridge National Laboratory car-to-car collision simulation capability, the National Highway Traffic and Safety Administration should support a major study to determine how well lightweight PNGV vehicles would fare in collisions with heavier vehicles and to assess potential improvements.
RESPONSE: The Safety Working Group (SWG) agrees with the essence of the Committee's recommendation that structural crashworthiness and safety in general is critical for PNGV vehicles. The SWG was chartered in December of 1999 to identify challenges and technical issues that are relevant to the safety of vehicles developed under PNGV, and provide advice and analysis through the PNGV Executive Committee to the OSG on the safety of such vehicles and how to enhance their safety. The SWG is a team of safety experts from government and industry working together to address the safety needs for PNGV.
The top two of the highest priority research needs are being pursued for projects in the next year.
Size independent of weight
- two proposed studies
FMVSS 111 side view systems in lieu of mirrors
- one proposed study
One of the top priorities, “Size independent of weight,” is partially addressed by NHTSA's ongoing fleet modeling study. The completion of this study is still approximately one year away at $3.5M. The current FY 2001 budget does not include the funds to complete the fleet modeling study. NHTSA is searching for a low level of funding to continue the efforts at a slower pace. The Oak Ridge National Laboratory (ORNL) simulation efforts are part of this fleet modeling study. However, four other contractors in addition to ORNL are working on the fleet modeling study and they all have capabilities to perform the car-to-car simulations. NHTSA has not yet chosen a contractor to perform the car-to-car simulations.
In addition to the NHTSA fleet modeling study, the SWG is pursuing a statistical study based on existing accident databases to identify facts and trends pertaining to how size affects vehicle safety. This study would complement the fleet modeling study to determine the safety issues surrounding a lightweight but not small size PNGV vehicle.
The other top priority research study will address human factor issues with replacing planar driver side view mirrors with alternative side view systems. Since alternative side view systems would be a significant change in the manner in which drivers receive information about their external driving environment, steps must be taken to insure that such a system is robust, easily used, and acceptable to drivers.
9) RECOMMENDATION: Defining automotive system/fuels trade-offs and establishing a basis for ensuring that the required fuels are available as higher efficiency vehicles become commercially available will require extensive cooperation among automotive and petroleum industry representatives at all levels of responsibility. Therefore, PNGV should strengthen and expand its cooperative efforts with the petroleum industry, including issues related to fuels for fuel cells. Government leadership will be necessary to initiate this cooperative effort and provide incentives for petroleum company involvement.
RESPONSE: We are having discussions around the possibility of having a joint symposium with the petroleum industry.
10) RECOMMENDATION: PNGV should consider conducting a comprehensive assessment of the consequences of fuel choices for fuel cells and their impact on PNGV's direction and ultimate goals. PNGV should assess the opportunities and costs for generating hydrogen for fuel cells at existing service stations and storing it on board vehicles and compare the feasibility, efficiency, and safety of this option with onboard fuel reforming. This study would help PNGV determine how much additional effort should be devoted to the development of onboard fuel reforming technologies.
RESPONSE: We concur with Recommendation #10. We have initiated a feasibility study to assess cost, efficiency, and emissions (including CO2) for various fuels/feedstocks, including off-board generation of hydrogen at existing refueling
stations. We are also planning a solicitation in Fiscal Year 2001 to contract for research and development of low-cost off-board hydrogen generation, purification, storage, compression, and dispensing. The solicitation will also include on-board storage research to complement the off-board R & D. These combined efforts will result in an integrated demonstration of on-board storage and off-board refueling technologies.
11) RECOMMENDATION: PNGV should continue its aggressive pursuit of lean combustion exhaust-gas after-treatment systems. The program should also pursue detailed systems modeling that could quantify the fuel economy penalty associated with using different technologies to meet the new Tier 2 emission standards. The modeling should also address how power train hybridization could be used to reduce emissions and what effects changing the primary energy converter would have on fuel economy trade-offs necessary to meet emissions standards.
Background on emissions modeling:
Experience has shown models that produce adequate results are much too large, complex and computational intensive to be of use in PC based models like Advisor and PSAT.
In the past, models that would be appropriate for inclusion in PC based models would use steady state engine maps. The failure of these models to properly account for transient and cold-start effects was their weakness. Results using these models were not of sufficient quality to merit their use, except possibly in providing the most rudimentary, at best, of directional effects.
Work on trying to address this issue is proceeding, as outlined below.
However, the time required properly develop better models, select appropriate replacements and validate/calibrate these models will likely produce results, assuming success, that would be beyond the time framework that would make them useful to the current PNGV program.
Emissions modeling work at ORNL in FY 2000:
A methodology is being developed to produce emission control device models based on analysis and reduction of emission data. Models for a catalyzed diesel particulates filter and a diesel oxidation catalyst are expected to be completed 3Q CY 2000.
Mapping, including cold start data, of the 1.9L VW & 1.7L Mercedes CIDI with high pressure common rail has been completed.
In order to be able to accurately measure ever decreasing emission levels, a new fast flow exhaust measurement capability is being developed which will also aid the understanding of transient emission behavior. Expected completion is 3Q CY2000.
An engine scaling algorithm is being developed for Advisor, similar in nature to that already in PSAT with completion in FY 2001.
Emissions modeling work at ANL in FY 2000:
Mapping of the 1.2L Ford Diata, 2.0L PSA & 1.7L Mercedes CIDI with high pressure common rail is beginning in CY 2000.
The Modal Emission Model has been developed and is available as a candidate for possible use with if not inclusion in PSAT and Advisor.
A new neural net emissions model is being developed specifically to address the need to account for transient/cold start emissions. Sufficient test data is being generated to define the model structures and “train” them. Preliminary results on Prius engine expected 3Q 2000 CY.
Work on methodologies to produce emission control device models based on analysis and reduction of emission data continues with the development of a NOX absorber model.
Work will begin on developing an algorithm for determining the “state of warmness” of an engine for predicting emissions during cold start.
Addressing the need for emissions data representative of SUV size, engine mapping will be done on a 5.9L Cummins Dl diesel both, with and without EGR.
Mapping of the 1.2L Ford Diata, 2.0L PSA & 1.7L Mercedes CIDI with high pressure common rail continues.
The neural net emissions model will be further tested and, if successful, its use will be expanded.
The Systems Analysis team will collaborate with the 4SDI to evaluate the various new emission models and their capabilities. The identification and implementation of improved emissions modeling is one of the team's FY 2001 goals.
12) RECOMMENDATION: PNGV should conduct trade-off analyses to establish relative priorities for fuel cell technical targets and cost targets.
RESPONSE: We concur with Recommendation #12. Trade-off analyses are being conducted through fuel cell system modeling done at Argonne National Laboratory, and through cost analyses being done by Arthur D. Little and Directed Technologies, Inc. Vehicle-level modeling is also being carried out by the National Renewable Energy Laboratory and will be coordinated with the PNGV Systems Analysis Technical Team. Specifically, trade-offs between efficiency, power density, and cost will be carefully examined before revising fuel cell targets in the PNGV Technical Roadmap.
13) RECOMMENDATION: PNGV should also support efforts to apply the materials improvements achieved in the program to improve lithium battery technology and to validate improved performance, life and safety.
RESPONSE: In FY 1999 the Electrochemical Energy Storage Technical Team established the Advanced Technology Development (ATD) program through the
Department of Energy. This program is a $7 million/year multi-national-laboratory effort focused specifically on life, abuse tolerance, and cost of lithium battery technology. Within the program one task is focused on screening the latest materials available in the commercial sector to identify those materials that possess inherent safety and high performance characteristics. Another is focused on developing advanced materials based on findings from the state-of the-art diagnostic studies. This information is being transferred to the battery developers at the regularly scheduled ATD quarterly review meetings. As a result of the program interactions, unique chemistries have been developed and are being assessed by the laboratories under the protection of non-disclosure agreements with the developers.
14) RECOMMENDATION: The Electrical and Electronics Systems Technical Team should closely monitor the progress towards meeting the cost goals of the automotive integrated power module and automotive electric motor drive and update and communicate realistic expectations for costs in 2004 to the systems-analysis team.
RESPONSE: The EE Tech Team has been seized with the problem of reducing cost of power electronics and motor drive from the day one in order to make the Hybrid Powertrain a reality. As such, we set our cost targets as the most affordable. If we compare these targets with commercial products available today they look too aggressive and the peer review panel members pointed out to us year before last. The first action we took last year was to have an in depth discussions on the basis for the cost projections with automotive experts at GM and Ford with some of the panel members.
In order to meet the targets for 2004, it is obvious that new technological challenges exist. After reviewing the new technologies proposed by the AIPM (Automotive Inverter Power Module) and AEMD (Automotive Electric Motor Drive) developers we felt more comfortable. They all promised that these cost targets could be achieved with the exception of the 42 V AIPM for parallel hybrid in the 15–20 kW range, as the currents are too high. In order to make sure that these projections are indeed achievable, which is also the concern of the NRC Peer Panel members as expressed above, we took two actions:
1. We requested all the developers to do a ‘Gap Analysis' and submit a time line for incorporating the new technologies within the contract framework.
2. We also requested DOE to fund two projects one related to the study of the ‘cost drivers of electric motor drives and power electronics' and another ‘appropriate materials and manufacturing technologies needed to meet the cost targets of filter capacitors'.
Once we have the resulted from these actions available to us we will be able to update and communicate realistic expectations of costs in 2004 to the system-analysis team as well as the NRC Peer Panel members. We expect to get some preliminary results of ‘Gap Analysis' by the end of this year. The two study projects have not been funded this year due to budget constraints. We might be able to kick off these studies with 2001 budget as and when it is approved. We are working closely with National Labs on this subject.
15) RECOMMENDATION: The Electrical and Electronics Systems Technical Team, in collaboration with the Vehicle Engineering Team, should undertake a comprehensive study to identify the electrical load requirements of the accessory system. Although the details of the accessory system will differ among the three USCAR partners, the impact of the accessory load is important enough that it should be considered explicitly by the system analysis team.
RESPONSE: The vehicle electrical load is an important consideration in the overall synthesis of the PNGV vehicle. This was recognized early on by both the EE team as well as the Systems Analysis team. Much effort was placed on this area during the first year of activity in order to address the overall electrical accessory system for the vehicle. It became apparent that the accessory load is very highly depended not only on the specific design intent for the vehicle, but how these loads are managed throughout the vehicle. Each of these can have a substantial influence on the magnitude of these accessory loads. In order to address this issue within the collaborative body of PNGV a “typical” system was configured and subsequently included in the EE and Systems teams analysis. The specifications utilized for the Electrical Team contract efforts include this definition. And the System analysis tools, both PSAT and Advisor are capable of detailed simulation and analysis of the accessory system and have been used within the OEM proprietary programs to aid in vehicle synthesis
Also the magnitude of the accessory loads influence on the vehicle fuel efficiency was recognized by the Vehicle Engineering team and the resultant work on alternative approaches to minimizing interior thermal losses (loads) was reviewed with the panel. We believe that focus has been placed on this area as evidenced by both the information presented at the NRC reviews as well as the resultant embodiments displayed within the three concept vehicles presents this spring. For further detail we would refer you to the review of the concept vehicles in the areas of:
– Electric accessory drives
– Thermally efficient interiors
– High efficient HVAC Systems
– Off cycle fuel economy
16) RECOMMENDATION: At this stage of the program, PNGV should direct its program toward an appropriate compromise between fuel economy and cost using the best available technology to ensure that a market-acceptable production-prototype vehicle can be achieved by 2004 that meets Tier 2 emission standards.
RESPONSE: Cost issues will be discussed during the Peer Review, Dec. 7–8, 2000.
17) RECOMMENDATION: Defining automotive system/fuels trade-offs and establishing the basis for planning for supplying required fuels as higher efficiency vehicles become commercially available will require extensive cooperation among automotive and petroleum industry representatives at all levels of responsibility. PNGV should expand and strengthen its cooperative efforts with the petroleum industry, including issues related to fuels for fuel cells. Government leadership will
be necessary to initiate this cooperative effort and provide incentives for petroleum company involvement.
RESPONSE: We are having discussions about having a joint symposium with the petroleum industry on fuels. Government cooperation and participation will be critical.
18) RECOMMENDATION: PNGV should undertake a study to assess the opportunities and costs for generating hydrogen for fuel cells at existing service stations and storing it on board vehicles and compare the feasibility, efficiency, and safety of this option with onboard fuel reforming. This study will help PNGV determine how much additional effort should be devoted to the development of onboard fuel reforming technologies.
RESPONSE: As part of the fuels task group efforts, we are considering hydrogen as a fuel and examining the safety aspects of such a choice.