8
Systems Analysis
Based on its understanding of the PNGV technical organization structure and Technical Roadmap (see chapter 9 for further discussion), the committee considers that vehicle systems analysis and modeling as defined in the road map are mandatory to:
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guide the technology teams in their research and development efforts and assure that all assumed metrics are optimized to the overall vehicle requirements
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provide the Vehicle Engineering Team with a means to make tradeoff studies between contender subsystems and components and to determine the minimum acceptable performance parameters for competing technologies
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objectively optimize selected subsystems and systems to meet performance requirements with minimum fuel consumption
The PNGV organization concluded at a USCAR/government modeling conference in November 1994 that the system analysis tools available are inadequate for the PNGV challenge. It was decided that a qualified contractor, capable of performing systems analysis and modeling was a vital requirement. After screening potential contractors, one was preliminarily selected in early 1995. Unfortunately, funding was delayed, other circumstances required a change of contractors to be made, and the contract award was not made until late October 1995. This delay of approximately one year could seriously impact the technology selection process and the 1997 milestone.
Other systems analysis projects have been identified, including analysis and design, improved subsystem models, integration models, and system analysis support. None of these projects has as yet been funded. As a result, the number of PNGV personnel working in the critical systems analysis area appears to be negligible.
The timely use of systems analysis to guide development is a critical issue for PNGV management to resolve. The timing presented in the Technical Roadmap for systems analysis efforts has been seriously delayed. The Technical Roadmap, in Section IIIA, clearly states:
The role of systems analysis in the PNGV is to support component, systems, and vehicle development by providing the analytical capability to efficiently and accurately assess competing technologies, and vehicle concepts against Goal 3 objectives and vehicle performance requirements. This will enable an objective evaluation of risk, benefit, and cost, in order to focus on the best options, with the least expenditure of resources.
This statement implies that the selection of optimal technologies for the design, fabrication, and assembly of the concept vehicles would be adversely affected by the absence, or inadequacy, of supporting subsystem and component tradeoff studies. These studies, in turn, depend on the availability of appropriate systems analysis methods.
Another important issue is the selection of the best system architecture for the concept vehicle. This is being approached on two fronts. As noted earlier, Chrysler, Ford, and General Motors have decided to carry on separate PNGV concept vehicle development in each of their respective engineering organizations. It has also been decided that the PNGV will not design and build a concept car. This is logical, if viewed from a proprietary-product standpoint and in terms of resource optimization. Each company will be using its in-house systems analysis and modeling capability to support its design selection. Although the PNGV team does plan to perform system analysis and vehicle engineering, the scope and specificity of the analysis must be designed with full understanding that the input from each automotive manufacturer may be vague in content. Each manufacturer is obliged to meet the same set of challenging requirements (specifications) for the Goal 3 vehicle. In the view of the committee, without a rigorous and disciplined systems analysis effort, the common requirements cannot be effectively established in a timely and coordinated fashion. Thus, the committee identifed the systems analysis effort as imperative. In addition, the committee considers that this effort would be most effectively directed and managed by a USCAR technical director.
The PNGV technology teams need direction on vehicle system requirements, and this should be provided by PNGV Vehicle Engineering Team, supported by systems analysis. This approach provides a single conduit for design information and design tradeoffs during the pre-competitive phase of the program. Vehicle system, subsystems, and component models will be created, which will support both the PNGV technology teams and the individual company vehicle teams. It would be helpful to the program if the USCAR partners
provided their in-house systems models to the PNGV to the extent appropriate. This action would help accelerate the systems analysis activity and make up for lost time.
The PNGV Vehicle Engineering Team must identify all of the breakthrough technology requirements for each of the subsystems under consideration. Technology evaluation and selection will be accomplished by both the PNGV Vehicle Engineering Team and the individual companies. It is not clear to the committee, based on the information it has received, specifically how the tradeoffs among subsystems will be accomplished. Some vehicle target metrics have been established; others still require definition; and others will probably require updating. There also must be an appropriate definition of metrics for each subsystem, driven by the system specifications.
The committee concluded that there are significant barriers to the accomplishment of the systems analysis and vehicle engineering tasks necessary to achieve the PNGV goals. While the technical teams for system analysis and vehicle engineering have been identified, along with an overall plan, very little has been accomplished because of a lack of funding and the delay in selecting an appropriate contractor to develop appropriate system, subsystem, and component models. Approximately 18 months remain before selected-vehicle system architectures must be quantitatively defined with metrics to allow the final selection of the concept vehicle architecture. To this end, tradeoff studies of all potentially relevant configurations are essential. Such studies may incorporate information relevant to market-based assessments of attractive technologies. Within the PNGV there does not appear to be complete awareness of the composite state of the art of the competing technologies, nor are the best models and simulation codes for these technologies available.
In the committee's view, there is a clear need for focused, central leadership to coordinate the technical teams and address overall vehicle requirements. A single USCAR Technical Director would be well positioned to lead the systems analysis and vehicle engineering efforts and to establish priorities for the subsystem technical teams.
RECOMMENDATIONS
Recommendation. The PNGV should assess the impact on the overall program schedule of the delay in implementing systems analysis and vehicle engineering tasks, and the need for remedial action. Priority projects must be identified and implemented by the technical teams as soon as possible.
Recommendation. The PNGV should formalize subsystem evaluation and selection process without delay, and performance criteria should be provided to
the PNGV technology teams. The systems analysis must be an iterative process that continually receives new information, updates models, and provides updated results from optimizations and tradeoff studies to system, subsystem, and component designers.
Recommendation. Overall vehicle system and subsystem analysis driving component developments should be under the control of a USCAR technical director.
