4.5 times higher per unit of volume of “fuel storage” and approximately 4 times higher per unit of mass of “fuel storage” than those of the HFCV. It seems likely that there will be certain applications, such as extended operation at higher loads or very long range transport, that will favor using a liquid HC as the on-vehicle energy carrier.

In addition, as new power plants with alternative energy carriers are developed, produced, and introduced into the market, there will be a significant time delay associated with their market penetration. As noted in Chapter 1, in the United States the vehicle fleet turnover in recent years is estimated to be about 15 years.2 Consequently the turnover time for completely new vehicle architectures to achieve significant market penetration will be measured in multiple decades (Bandivadekar et al., 2008; Weiss et al., 2000). During this transition the dominant power plant for mobility systems will continue to be ICE vehicles fueled with a hydrocarbon fuel (e.g., gasoline, diesel fuel, or biofuel).3

Consequently, it is important to maintain an active ICE and liquid fuels R&D program at all levels: industry, government laboratories, and academia, to expand the knowledge base to enable the development of technologies that can reduce the fuel consumption of transportation systems powered by ICEs. The near-term introduction of such technologies into existing production facilities will reduce the growth in transportation petroleum use during a transition to alternative power plants and power-train configurations. This is the focus of the Partnership’s advanced combustion and emission control (ACEC) technical team.

The overarching goals, technical targets, and program structure of the ACEC technical team are basically the same as reported in the Phase 2 review of the program (NRC, 2008). The technical team has established the following technical engine target goals for 2010:

  • Engine peak brake thermal efficiency (BTE): 45 percent

  • Nitrogen oxides (NOx) and particulate matter (PM) emissions: Tier 2 Bin 5 (T2B5)

  • Power-train cost: <$30/kW

The general focus of the ACEC technical team’s work to achieve these targets continues to be lean-burn, direct-injection engines for vehicles fueled by diesel, gasoline, and biofuel or other alternative fuels, provided appropriate carbon emission mitigation is accomplished during their production. Within this broad area specific foci include the following:


Of course, this can vary depending on the economic expectations of consumers, who may change their behavior depending on the state of the economy.


In this discussion, hybrid vehicles are included as ICE power trains fueled with a liquid HC fuel. In the hybrid, the energy source is the HC fuel; the hybridization allows more optimal use of the engine and vehicle power-train system.

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