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NRC releases second report on 21st Century Truck Partnership

The National Research Council (NRC) last week released a pre-publication version of its second report reviewing the 21st Century Truck Partnership (21CTP). The 21CTP is a cooperative research and development (R&D) partnership including four federal agencies—the US Department of Energy (DOE), US Department of Transportation (DOT), US Department of Defense (DOD), and the US Environmental Protection Agency (EPA)—and 15 industrial partners.

The purpose of the 21CTP is to reduce fuel consumption and emissions; increase heavy-duty vehicle safety; and support research, development, and demonstration to initiate commercially viable products and systems. This is the NRC’s second report on the topic and it includes the committee’s review of the Partnership as a whole, its major areas of focus, 21CTP’s management and priority setting, efficient operations, and the new SuperTruck program.

In July 2010, the National Research Council (NRC) appointed the Committee to Review of the 21st Century Truck Partnership, Phase 2, to conduct an independent review of the 21st Century Truck Partnership (21CTP).
The Phase 2 review follows on the original NRC Phase 1 review of the Partnership conducted in 2007 and resulting in a report issued in 2008.
The initial report recommended continuation of the program, but with revisions and better balancing to match current funding and technology levels. (Earlier post.)

Overall, the report recommends that the 21CTP should be continued to help meet the nation’s goal of reduced fuel consumption in the transportation sector. In addition, the report says, the Partnership needs to review whether additional partners—such as major truck and component manufacturers that are not currently members—that could contribute to the R&D program should be recruited. Research funding should be commensurate with well-formulated goals that are strategic to reducing the fuel consumption of heavy-duty vehicles while improving safety, and all projects should be prioritized so that the 21CTP R&D program can be implemented within the available budget.

Further, the report recommends that 21CTP program goals should continue to be established, reviewed, updated, related to available funding, and clearly stated in measurable engineering terms. The white papers defining the various technical areas of R&D should be reviewed and revised, as appropriate, periodically and prior to any future review. Given the “virtual” nature of the Partnership among 4 agencies and 15 industrial partners, the projects that are considered to be part of 21CTP should be better defined and, if part of the Partnership, indicated by a 21CTP notation in any 21CTP documentation, the report said.

The strategic approach of the Partnership includes:

  1. developing and implementing an integrated vehicle systems R&D approach that validates and deploys advanced technology;
  2. research for engine, combustion, exhaust aftertreatment, fuels, and advanced materials;
  3. research focused on advanced heavy-duty hybrid propulsion systems;
  4. research to reduce parasitic losses;
  5. development of technologies to improve truck safety;
  6. development and deployment of technologies that substantially reduce energy consumption and exhaust emissions during idling; and
  7. the validation, demonstration, and deployment of advanced truck and bus technologies, and growing their reliability sufficient for adoption in the commercial marketplace.

Among the findings and recommendations, by area, from the new report are:


Finding 3-1. By combining High Efficiency Clean Combustion (HECC) and Waste Heat Recovery (WHR), each demonstrating greater than 10% improvement in BTE, together with other technologies, it should be possible to improve BTE by 20% to achieve the original DOE target of 50% peak BTE.

Finding 3-2. Efforts to achieve 55% BTE are going to require complex and expensive technologies. It will be some time before it becomes clear whether there is a production-feasible and cost-effective way to achieve the 55% BTE target. The committee believes that this target carries considerable risk, even at the test cell demonstration stage.

Recommendation 3-1. The 21CTP fundamental research program should continue to provide important enablers for the 55% BTE goal, and DOE should continue to look for leverage opportunities with other government- and industry-funded projects.

Recommendation 3-2. The DOE should ensure that the engine R&D for the goal of 50% BTE at over-the-road cruise conditions and the stretch goal of 55% BTE in an engine in a laboratory that will now be carried out under the SuperTruck program receive the appropriate share of the SuperTruck funding and benefit extensively from the DOE-funded research programs in advanced engine combustion.

Finding 3-7. In spite of efforts to reduce the fuel consumption of light-duty and heavy- duty vehicles and to develop biomass-derived fuels, petroleum will remain the primary source of light-duty and heavy-duty vehicle fuel for many years to come. Whereas future US gasoline demand is expected to be flat for the next 20 years, diesel fuel demand is expected to grow, necessitating changes in refinery operations.

Recommendation 3-4. The DOE should reinstate its program for advanced petroleum-derived fuels with the objective of maximizing the efficiency of their use.

Finding 3-11. The demands on the aftertreatment system and its performance are intimately linked to the combustion process taking place within the cylinder. Consequently, the aftertreatment system must be developed and its performance evaluated in conjunction with the combustion system. The 21CTP realizes this, and its new goals for the aftertreatment program specifically state this.

Recommendation 3-7. The aftertreatment program within the 21CTP should be continued, and DOE should continue to support the activities of the Cross-cut Lean Exhaust Emissions Reductions Simulations (CLEERS) program that interface with the activities of the aftertreatment technical community at large.


Recommendation 4-3. As partners of the 21CTP, EPA and DOT’s NHTSA should work with CARB to develop test procedures for the certification process for criteria emissions so that the emissions benefits of hybridization will be recognized, allowing the reduction in size or simplification of the emission control system of hybrid heavy-duty vehicles to be realized.

Finding 4-6. Six new stretch technical goals have been established by the 21CTP for heavy-duty hybrid vehicles. The committee agrees with the 21CTP that these are indeed stretch goals. It is expected that a significant budget would be required through the target dates specified in the new goals, and a significant increase from the zero budget for heavy-duty hybrid R&D over the past 3 years would be required.

Recommendation 4-5. The 21CTP should establish plans and develop realistic budgets for accomplishing the six new stretch goals for heavy-duty hybrid vehicles in accordance with the committee’s findings, explain the rationale behind the new goals, and provide the current status of the applicable technology for each of the goals so that the magnitude of the tasks for each can be assessed.


Finding 6-1. The DOE, EPA, and DOT have funded a wide variety of idle reduction projects focused on implementation. A consolidated list of the funding provided for these projects was not provided to the committee, however, and the effectiveness of these projects could not be evaluated. The national patchwork of anti-idling regulations is an impediment to broader use of anti-idling measures.

Recommendation 6-1. The DOE, EPA, and DOT should develop a consolidated list of the funding provided for the idle reduction projects, review the effectiveness of these projects, and formulate a coordinated and consistent plan to encourage the adoption of idle reduction technologies to meet the goal of reducing fuel use and emissions produced by idling engines by at least two-thirds by 2017. The EPA and DOT should work to find incentives for states to promulgate uniform anti-idling regulations.

Finding 6-3. The Delphi solid oxide fuel cell (SOFC) auxiliary power unit (APU) provides several advantages over diesel APUs, but it has significant issues in its current development status, including the following: low efficiency of 25% versus DOE’s goal of 35%, and low demonstrated output power of 1.5 kW versus 3.0 kW believed sufficient by Delphi and 5 kW of typical diesel APUs; limited demonstrated durability; 2- to 5-hour warm-up time to the 750°C operating temperature; and high cost. The 10-year funding for this program expires in 2011.

Recommendation 6-3. The DOE should reassess the viability of the SOFC APU, particularly for application to the SuperTruck program, considering the following: (1) SOFC APU is still in the laboratory, (2) the low efficiency of 25 percent versus the DOE goal of 35 percent, (3) the low 1.5 kW output compared to the typical 5 kW diesel APUs, (4) the disadvantages associated with the requirement for continuous operation at 750°C, and (5) the expiration of funding from the DOE Office of Fossil Energy and EERE Fuel Cell Technologies Program of the DOE Office of Energy Efficiency and Renewable Energy after 10 years of development. The DOE should coordinate more closely with DOD in its fuel cell APU developments to ensure that the best technology is being pursued for the 21CTP’s Goal 7 in the engine idle reduction focus area; that goal relates to the development and demonstration of viable fuel cell APU systems for military and other users.

Finding 6-4. Idle reduction technologies could provide 6% reduction in overall fuel consumption for Class 8 long-haul trucks with sleeper cabs, which is nearly 30% of the 20% reduction in the fuel consumption required to meet the proposed EPA/NHTSA 2017 fuel efficiency standards.

Recommendation 6-4. The 21CTP should review and potentially revise its idle reduction plans and goals in view of the fact that the proposed 2017 fuel efficiency standards provide an incentive for the adoption of idle reduction technologies as a means for achieving these standards for Class 8 long-haul trucks with sleeper cabs.


Three projects have been selected for awards under the DOE’s SuperTruck program (earlier post) to improve the fuel efficiency of Class 8 long-haul freight trucks. These projects will receive $115 million in DOE funding to develop and demonstrate full vehicle system-level technologies by 2015. Two of the project teams (Cummins, Inc. and Daimler Trucks North America, LLC.) received ARRA funding for their projects, and Navistar, Inc. will be funded from DOE appropriations:

  • Cummins, Inc. will develop and demonstrate a highly efficient and clean diesel engine, an advanced waste heat recovery system, an aerodynamic Peterbilt tractor and trailer combination, and a solid oxide fuel cell auxiliary power unit to reduce engine idling.

  • Daimler Trucks North America, LLC will develop and demonstrate technologies including optimized combustion, engine downsizing, electrification of auxiliary systems such as oil and water pumps, waste heat recovery, improved aerodynamics, hybridization, and possibly a fuel cell auxiliary power unit to reduce engine idling.

  • Navistar, Inc. will develop and demonstrate technologies to improve truck and trailer aerodynamics, combustion efficiency, waste heat recovery, hybridization, idle reduction, and reduced rolling resistance tires.

Target goals for the SuperTruck projects are:

  • A 50% increase in vehicle freight efficiency measured in ton-miles per gallon, which translates to a 33% reduction in load-specific fuel consumption (gallons per 1,000 ton-miles).

  • A 20% improvement through engine thermal efficiency development, and achieving 50% brake thermal efficiency (BTE) under highway cruise conditions.

  • Evaluate potential approaches to 55 percent BTE in an engine via modeling, analysis, and potentially also laboratory tests.

Finding 8-4. The committee believes that the SuperTruck project teams have developed plans that address the needs of the SuperTruck program and that have a reasonable chance for success. The keys to success include proper implementation of the plans along with the flexibility to adapt to new information and intermediate results during the course of the project.

Finding 8-5. The SuperTruck projects allow each team to design its own test duty cycle(s) within certain constraints. One negative consequence of this approach is that the three trucks may never be tested using a common cycle for comparison.

Finding 8-6. The SuperTruck projects go beyond the scope of previous 21CTP projects. Instead of relying entirely on simulations and laboratory testing, each of these projects will result in a drivable truck. The committee believes that it is important to take technologies that have been developed to date and implement them in a real vehicle. Often, the application of new technologies in real-world applications yields unexpected results, and these results must be explored before any new technology can be considered ready for production implementation.

Recommendation 8-2. The DOE and the SuperTruck contractors should agree on at least one common vehicle duty cycle that will be used to compare the performance of all three SuperTruck vehicles. In addition, fuel consumption improvements should be calculated on the basis of the EPA/NHTSA fuel consumption regulations.




Here's a "proper" Super-Truck program, in order:

1. Engine idle reduction (elimination)
2. Aerodynamics
3. Engine down-sizing
4. Weight reduction

In all seriousness, doubling the mpg of Class 8 trucks is easily achievable (and very economical) through a combination of these measures.

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