US National Academies release third review of the 21^st Century Truck Partnership

15 September 2015

The US National Academies released a third review report of the 21^st Century Truck Partnership (21CTP)—a public-private R&D initiative to reduce fuel consumption and emissions from heavy-duty engines and vehicles. The third review follows the Phase 2 review released in 2011 and Phase 1 review published in 2008.

The 21st Century Truck Partnership comprises four US federal agencies and 15 industrial partners, including major heavy-duty truck and engine makers. The 21CTP was formed in 2001 to reduce fuel usage and emissions in trucks of Class 3 through Class 8. Significant progress has been made since the previous reviews:

• The engine systems goal of a 50% peak brake thermal efficiency (BTE) has been achieved. A pathway to achieve 55% is being developed.
• The SuperTruck projects incorporated a number of vehicle power demand technologies that accounted for about 56 to 74% of the total fuel consumption reductions (with 26 to 44% coming from the engine efficiency improvements).
  • One truck (Cummins-Peterbilt) has achieved a freight efficiency of over 175 ton-miles per gallon, compared to a 2009 model baseline efficiency of 99 ton-miles per gallon. In terms of fuel economy, the truck achieved 10.7 miles per gallon (mpg), compared to the baseline truck at 6.45 mpg. As for load-specific fuel consumption (LSFC), the truck achieved 5.7 gallons/1,000 ton-miles, down 43% from the baseline LSFC of 10.0 gallons/1,000 ton-miles.
  • A second truck (Daimler) has doubled fuel economy from a 2009 baseline of 6.1 mpg to 12.2 mpg over one long-haul route, with a 120% increase in freight efficiency in ton-miles per gallon from a 2009 baseline of 94 ton-miles per gallon to 206 ton-miles per gallon. LSFC was reduced by 55% on one route and by 49% on a second, lower speed route. On the route that produced the 12.2 mpg result, the LSFC was 4.85 gallons per 1,000 ton-miles, compared to 10.6 gallons per 1,000 ton-miles for the 2009 baseline.
• Hybrid vehicle systems have demonstrated significant fuel consumption and emissions reductions in a number of MHDV applications, but their cost prohibits commercial deployment. In addition, the SuperTruck project results show a limited potential benefit on long-haul duty cycles for hybrid systems using currently available technology. The 21CTP hybrid team is considering a proposal to restructure its mission and focus, which the Phase 3 Review Committee supports.

The report provides detailed overview and recommendations for all areas of the Partnership, including management strategy and priority setting, engine systems, hybrid vehicles, safety, and the SuperTruck program.

Engine systems comprise the engine, the aftertreatment, and the fuel as an interlinked system. The 21CTP Engine Systems program is well managed and incorporates a closely coordinated set of research activities. Federal funding for the SuperTruck projects for diesel engine systems R&D to achieve 50 and 55% BTE amounts to about $51.6 million. The key recommendations in this program area are:

• The fundamental diesel engine research program pursuing technologies, combustion processes and engine architectures to achieve 55% BTE should continue to be a focus of the 21CTP engine activities. However, the experiments and modeling should maintain a focus on dynamometer R&D, as opposed to attempting to build a demonstration vehicle. The achievement of this goal should be extended from 2015 to 2020 in order to have sufficient time to carry out R&D on this stretch goal.
• The Partnership should continue to fund work on improved SCR NOx efficiency (mainly low temperature without compromising high temperature efficiency) and aging and poisoning effects. California’s and, potentially EPA’s, move toward further heavy-duty NOx reductions to meet National Ambient Air Quality Standards for ozone will be critical.
• Technologies such as an SCR catalyst on a DPF or others that have the potential to reduce the volume, weight, and cost of the aftertreatment system should be a part of the program to develop a 55% BTE engine.

The SuperTruck initiative is a major component of the 21CTP, supporting four teams that are separately developing prototype Class 8 tractor-trailer trucks that incorporate a suite of fuel-saving technologies including high efficiency engines, lightweight materials, aerodynamic improvements, and idle reduction. The four SuperTruck teams are Cummins-Peterbilt, Daimler Trucks North America, Navistar, and Volvo Technology of North America. The SuperTruck projects are supported through government-industry cost sharing contracts with the total budget for the four projects of about $284 million. The American Recovery and Reinvestment Act of 2009 provided federal funding of about $86 million to two of the teams.

The two teams that have finished their vehicle demonstrations (Cummins-Peterbilt and Daimler) have produced results substantially better than the targets called for in the SuperTruck contracts. Both teams reached the 50% engine BTE target, but they went well beyond the goals for overall freight efficiency (freight ton-miles per gallon) improvement. The remaining two teams have plans to match or exceed their program goals by the time their projects conclude in 2015 and 2016.

The main recommendations for the SuperTruck program are:

• The SuperTruck demonstration vehicles represent a huge investment. DOE should consider ways of extracting additional research results from this investment by using the trucks that have been built to evaluate additional technologies.
• As the four SuperTruck projects conclude, it is not too soon to develop proposals to build on their momentum. Because of the great value demonstrated by the SuperTruck program, DOE should be working on at least one vehicle integration project at any given time. Owing to likely funding limitations, it will not be possible to have three or four similar projects running. A range of integration projects are possible, including these: (1) A regional haul SuperTruck, (2) A heavy-duty vocational SuperTruck (refuse, dump, etc.), (3) A SuperTrailer program to help trailer manufacturers build engineering capability, (4) A delivery truck of Class 3, 4, 5, or 6.
• The SuperTruck platforms include technologies with a wide range of production readiness and not all technologies incorporated into the prototypes would be cost effective in an actual production vehicle. Moreover, directly comparing the results between the four SuperTruck vehicles has proved difficult, because each SuperTruck project was allowed to select different baseline vehicles and test routes. Any future system integration program with more than one team should entail performance testing on identical duty cycles, so that differences in the performance of specific technologies can be better understood.

The Phase 3 Review report has been authored by a Review Committee with academia and industry participation, chaired by professor John Johnson of the Michigan Technological University.

Source: National Academies Press