Status: Plans for achieving this goal were not reviewed with the committee. As noted in an earlier section, significant progress in low-temperature combustion has been realized through the use of gasoline or dual gasoline and diesel fuels. The DOE should recognize this progress in defining this goal and developing specific plans for achieving the goal.

Finding 3-9. The DOE established three different sets of goals for the fuels program from 2008 to 2011, which made an assessment of progress against the goals difficult. In total, little progress has been made toward the achievement of these DOE goals, which were not specified goals of the 21CTP.

Recommendation 3-6. The DOE fuel goals should be re-evaluated in line with the FY 2012 budget and the recommendations of this report. Specific plans for achieving these goals should be established.

AFTERTREATMENT SYSTEMS

Introduction

Considerable effort and research funding have been focused on improving aftertreatment systems as part of the 21CTP. This effort is complementary to the development of combustion processes that would minimize or preclude the in-cylinder formation of criteria pollutants. It is most appropriate to think of the combustion processes within the cylinder and the aftertreatment devices within the exhaust as an interconnected system. Minimal emissions leaving the combustion chamber result in reduced demands on the aftertreatment system, allowing for simpler, less expensive aftertreatment systems. Also, highly effective aftertreatment systems can facilitate different engine calibrations for better efficiency, which would otherwise have been precluded because of emission constraints. Aftertreatment research and development must be done with an eye toward the likely progress in combustion system development.

In addition, aftertreatment systems are the subject of extensive research within the technical community. Consequently it is critical for the 21CTP be aware of the broad scope of activities taking place outside of its program and to make sure that the research activities within its purview address fundamental concerns and are not already being done as part of the research and development efforts of the other agencies or industry.

To this end, the research structure of the 21CTP aftertreatment program is well organized. The research programs are built around teams with participation from national laboratories, universities, and relevant stakeholder industries. This is directly stated in the goals of their aftertreatment program. The research focuses on developing new technologies and on gaining an enhanced fundamental understanding of catalysis and governing phenomena limiting the effectiveness of current approaches. Success in these programs could lead to combining multiple aftertreatment approaches into a single unit, developing catalysts with higher resistance to poisoning, and implementation of retrofit systems.

The 21CTP aftertreatment research has already helped manufacturers meet the EPA 2007 and 2010 new-engine emissions standards. The system architecture generally being applied to meet U.S. EPA 2010 emissions is shown in Figure 3-4. The attainment of these emission standards is providing substantial health and environmental benefits by reducing ground-level ozone and fine particulates (mass as well as number), in addition to regional haze. Thus, con-

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FIGURE 3-4 Emission control system architecture generally being applied to meet 2010 new engine emissions standards of the Environmental Protection Agency. Acronyms are defined in Appendix I. SOURCE: DOE (2011a).



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