B
Statement of Task

The committee formed to carry out this study will provide updated estimates of the cost and potential efficiency improvements of technologies that might be employed over the next 15 years to increase the fuel economy of various light-duty vehicle classes. Specifically, the committee shall:

  1. Reassess the technologies analyzed in Chapter 3 of the NRC report, Impact and Effectiveness of Corporate Average Fuel Economy (CAFE) Standards (2002), for efficacy, cost, and applicability to the classes of vehicles considered in that report. In addition, technologies that were noted but not analyzed in depth in that report, including direct injection engines, diesel engines, and hybrid electric vehicles, shall be assessed for efficacy, cost and applicability. Weight and power reductions also shall be included, though consideration of weight reductions should be limited to advances in structural design and lightweight materials. The assessments shall include the effects of “technology sequencing”—in what order manufacturers might conceivably incorporate fuel economy technologies, and how such ordering affects technology cost and applicability.

  2. Estimate the efficacy, cost, and applicability of emerging fuel economy technologies that might be employed over the next 15 years. The assessments shall include the effects of technology sequencing as defined in (1) above.

  3. Identify and assess leading computer models for projecting vehicle fuel economy as a function of additional technology. These models would include both:

    • Lumped parameter (or Partial Discrete Approximation) type models, where interactions among technologies are represented using energy partitioning and/or scalar adjustment factors (also known as synergy factors), and

    • Full vehicle simulation, in which such interactions are analyzed using explicit drive cycle and engine cycle simulation, based on detailed vehicle engineering characteristics (e.g., including engine maps, transmission shift points, etc.).

  1. Check the models against current, known fuel economy examples and select one of each type to perform the analyses of the effects of the technologies in 1 and 2 above.

  2. Develop a set of cost/potential efficiency improvement curves, as in Chapter 3 of the 2002 NRC report, that is guided by the following question: “What is the estimated cost and potential fuel economy benefit of technologies that could be applied to improve the fuel economy of future passenger vehicles, given the constraints imposed by vehicle performance, functionality, safety and emission regulations?” The ten vehicle classes considered in the 2002 report shall be analyzed, including important variants such as different engine sizes (e.g., 6 and 8 cylinders). Most analyses shall be performed with the lumped parameter model, but sufficient cases to ensure overall accuracy shall be checked with the engine mapping model.

  3. Define and document the specific methodology(ies) and inputs used to estimate the incremental costs and benefits of the fuel economy technologies chosen by the committee, including the methods used to account for variations in vehicle characteristics (e.g., size, weight, engine characteristics) and to account for the sequential application of technologies. Use flow charts or similar methods to document sequencing upon which the committee’s estimates of incremental costs and benefits are based. Although methodologies vary, the committee’s report should detail all of its calculation methodology(ies), even those as basic as simple mathematical relationships (if used) and as complex as structural representations, such as decision trees (if used). It should do so to levels of specificity, clarity and completeness sufficient for implementation and inte-



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OCR for page 163
B Statement of Task The committee formed to carry out this study will pro- cycle simulation, based on detailed vehicle engi- vide updated estimates of the cost and potential efficiency neering characteristics (e.g., including engine maps, improvements of technologies that might be employed over transmission shift points, etc.). the next 15 years to increase the fuel economy of various light-duty vehicle classes. Specifically, the committee shall: Check the models against current, known fuel econo- my examples and select one of each type to perform 1. Reassess the technologies analyzed in Chapter 3 of the the analyses of the effects of the technologies in 1 and NRC report, Impact and Effectiveness of Corporate 2 above. verage Fuel Economy (CAFE) Standards (2002), A for efficacy, cost, and applicability to the classes of 4. Develop a set of cost/potential efficiency improve- vehicles considered in that report. In addition, tech- ment curves, as in Chapter 3 of the 2002 NRC report, nologies that were noted but not analyzed in depth in that is guided by the following question: “What is the that report, including direct injection engines, diesel estimated cost and potential fuel economy benefit of engines, and hybrid electric vehicles, shall be assessed technologies that could be applied to improve the fuel for efficacy, cost and applicability. Weight and power economy of future passenger vehicles, given the con- reductions also shall be included, though consideration straints imposed by vehicle performance, functional- of weight reductions should be limited to advances ity, safety and emission regulations?” The ten vehicle in structural design and lightweight materials. The classes considered in the 2002 report shall be analyzed, assessments shall include the effects of “technology including important variants such as different engine sequencing”—in what order manufacturers might sizes (e.g., 6 and 8 cylinders). Most analyses shall be conceivably incorporate fuel economy technologies, performed with the lumped parameter model, but suffi- and how such ordering affects technology cost and cient cases to ensure overall accuracy shall be checked applicability. with the engine mapping model. 2. Estimate the efficacy, cost, and applicability of emerg- 5. Define and document the specific methodology(ies) ing fuel economy technologies that might be employed and inputs used to estimate the incremental costs and over the next 15 years. The assessments shall include benefits of the fuel economy technologies chosen by the effects of technology sequencing as defined in (1) the committee, including the methods used to account above. for variations in vehicle characteristics (e.g., size, 3. Identify and assess leading computer models for weight, engine characteristics) and to account for the projecting vehicle fuel economy as a function of addi- sequential application of technologies. Use flow charts tional technology. These models would include both: or similar methods to document sequencing upon which the committee’s estimates of incremental costs • Lumped parameter (or Partial Discrete Approxima- and benefits are based. Although methodologies vary, tion) type models, where interactions among tech- the committee’s report should detail all of its calcula- nologies are represented using energy partitioning tion methodology(ies), even those as basic as simple and/or scalar adjustment factors (also known as mathematical relationships (if used) and as complex synergy factors), and as structural representations, such as decision trees (if • Full vehicle simulation, in which such interactions used). It should do so to levels of specificity, clarity and are analyzed using explicit drive cycle and engine completeness sufficient for implementation and inte- 163

OCR for page 163
164 ASSESSMENT OF FUEL ECONOMY TECHNOLOGIES FOR LIGHT-DUTY VEHICLES gration into models that project the fuel economy ca- The committee’s analysis and methodologies will be pability of vehicles, fleets and manufacturers, includ- documented in two NRC-approved reports. An interim report ing fleets specified at the level of individual vehicle will discuss the technologies to be analyzed, the classes of models, engines, and transmissions. The report should vehicles which may employ them, the estimated improvement also provide and document estimates of all input data in fuel economy that may result, and the models that will be required for implementation of these methodologies. used for analysis. The final report will include the detailed 6. Assess how ongoing changes to manufacturers’ refresh specifications for the methodologies used and the results of and redesign cycles for vehicle models affect the in- the modeling, and will make use of the input from the interim corporation of new fuel-economy technologies. report and any new information that is available.