ous emergence problem by allowing the qualitative testing of alternate futures. The quantitative implications of these futures might be understood through simple and transparent spreadsheet models.

Advanced Combustion and Emissions Control

Higher efficiency and reduced emissions as compared to those associated with current internal combustion engine (ICE) vehicles will be very important to the success of biofuels, advanced hybrid electric vehicles (HEVs), and even plug-in hybrid electric vehicles (PHEVs). In addition, the use of hydrogen fuel in ICEs can offer an alternative for expanding the availability of hydrogen for refueling vehicles prior to the widespread distribution of fuel cell vehicles. There is also the potential for homogeneous charge compression ignition (HCCI) engines to provide even better combinations of efficiencies and emissions than either diesel or spark-ignited ICEs. Such advances can be implemented by a better understanding of fundamental processes, and such is the primary orientation of these efforts. However, almost all aspects of engine operation are being pursued by the Partnership.

Among the accomplishments in this area were the following:

  • The demonstration of a peak brake thermal efficiency of 43 percent for conventionally fueled and 45 percent for hydrogen-fueled ICEs has taken place. Engines with these efficiencies operating in hybrid vehicles could result in system efficiencies approaching those of fuel cell vehicles.

  • The development of a predictive model for spark-assisted HCCI combustion is complete. This could help lead to the elusive solutions for successfully controlling HCCI engines.

The fundamental research being performed by the advanced combustion and emission control (ACEC) technical team is generating the knowledge base necessary to identify how to optimize the combustion process at any operating condition. This understanding is being incorporated into detailed computational fluid dynamic (CFD) simulations, which in turn accurately replicate the experimental results with minimum adjustable numerical tuning (Ge et al., 2010).

Primary barriers include the following:

  • In all of these endeavors, the key barrier continues to be the need for detailed fundamental understanding of the chemical, thermal, and physical processes taking place within the power train and combustion system.

  • Also, as with almost all technologies being pursued, cost is a barrier. Specifically, the technical team has had difficulty specifically addressing its cost target. The team has assumed that the base engine cost will be



The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001
Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement