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Review of the 21st Century Truck Partnership, Second Report (2012)

Chapter:6 Engine Idle Reduction

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Suggested Citation:"6 Engine Idle Reduction." National Research Council. 2012. Review of the 21st Century Truck Partnership, Second Report. Washington, DC: The National Academies Press. doi: 10.17226/13288.
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6

Engine Idle Reduction

INTRODUCTION

Overnight and workday idling of trucks is estimated to consume well over 2 billion gallons of fuel annually in the United States (DOE, 2011). Extended idling by commercial trucks costs truck owners about $6 billion annually and wastes more than 1 percent of the petroleum used in the United States. Much of this petroleum use could be avoided by installing idle reduction technologies, adopting more efficient freight-scheduling policies, or in some cases simply turning off the engines. In addition to the fuel consumed, idling produces emissions and noise. Overnight idling is used to keep a truck’s cab and/or sleeper heated or cooled, to keep the fuel and engine warm in winter for easier starting, to provide power to operate electrical appliances, and to keep the batteries charged. A long-haul truck idles an estimated 1,800 to 2,400 hours per year when parked overnight (DOE, 2011). Workday idling includes creeping along in queues at ports and depots. Every hour that a truck idles unnecessarily is equivalent in fuel consumption to about 4 to 5 miles of driving and adds an estimated $0.15 in maintenance costs.1

Solutions to eliminate overnight idling are shown in Table 6-1. They include engine controls (for automatic shutdown/start-up systems), fuel-operated heaters (FOH), auxiliary power units (APUs), battery-powered heating and cooling systems, and shore power or truck stop electrification (also called Electrified Parking Spaces [EPS]) (NRC, 2010). The attributes provided by each of these idle reduction technology solutions are shown in the table. The cells in Table 6-1 are shaded light green to indicate favorable attributes, yellow shading indicates mild drawbacks, and dark orange indicates major drawbacks. The U.S. Environmental Protection Agency (EPA), through its SmartWay program’s contacts with truck manufacturers and fleets, estimates that approximately 30 percent of the existing fleet has some type of idle reduction technology.2 The most prevalent onboard technology, determined by a survey conducted by the American Transportation Research Institute (ATRI) of 55,000 truckers, was direct-fuel-fired heaters (32 percent), followed by battery-powered air conditioners (24 percent), while auxiliary power units APUs were used by 12 percent of the respondents (American Transportation Research Institute, 2006).

The overall goal of the engine idle reduction portion of the 21st Century Truck Partnership (21CTP) is to reduce fuel use and emissions produced by idling engines. The metric for this goal, which was provided to the committee in a November 2010 presentation and in previous versions of 21CTP white papers since 2007, was an 85 percent reduction in idling fuel consumption in the period 2002 to 2017.3 An August 2010 white paper draft revised the goal to a two-thirds reduction, based on discussions with industrial partners on the most appropriate and achievable goals using a variety of factors (DOE, 2010). However, in the February 2011 “21CTP White Paper on Idle Reduction,” the quantification of this goal was deleted (DOE, 2011). To date, the 21CTP has not been able to carry out surveys to measure quantitatively the progress being made toward the previously stated goal owing to the absence of funding for such studies. Only qualitative observations can indicate the increased adoption rate of these devices for which the primary drivers have been (1) the high cost of diesel fuel and (2) the regulatory measures adopted in some states and cities to reduce idling.

There are restrictions on engine idling in 46 states and jurisdictions. Many states have strict regulations in more than one city, whereas the regulations of other states are statewide. Sometimes the regulations for a city are different from those of the state. Some of the localities have started enforcing

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1 Glenn Keller, ANL, “Idle Reduction Accomplishments,” presentation to the committee, November 15, 2010, Washington, D.C.

2 Answers provided by Ken Howden, DOE Office of Vehicle Technologies, to committee questions 5(b).

3 Glenn Keller, ANL, “Idle Reduction Accomplishments,” presentation to the committee November 15, 2010, Washington, D.C. This overall goal has been used to formulate the 21CTP technical goals.

Suggested Citation:"6 Engine Idle Reduction." National Research Council. 2012. Review of the 21st Century Truck Partnership, Second Report. Washington, DC: The National Academies Press. doi: 10.17226/13288.
×

TABLE 6-1 Comparison of Attributes of Idle Reduction Systems

Idle Reduction Technology Heating Cooling Electric Requires Recharge Infrastructure Service Fee Emissions Control Needed? Idle Time Avoided per Year Fuel Use (gal/hr) % Benefit Cost
Engine Control Yes Yes Yes No No No 1,500 to 2,400 ~0.5 3% $1,000 to $4,000
Heater Yes No No No No No 500 to 800 0.2 to 0.3 1.3 to 2.3% $1,000 to $3,000
Auxiliary Power Unit Yes Yes Yes No No In California 1,500 to 2,400 0.2 to 0.3 4 to 7% $6,000 to $8,000
Battery Yes Yes Some Yes No No 1,500 to 2,400 5 to 9% $3,000 to $8,000a
Shore power Yes Yes Yes Yes Yes Yes 1,500 to 2,400 5 to 9% ~$100

NOTE:

image Green: Favorable Attribute
Yellow: Mild Drawback
Dark Orange: Major Drawback

a May require a diesel particulate filter, at an additional cost of $3,000.

SOURCE: NRC (2010), Table 5-24, p. 125.

anti-idling regulations more aggressively (DOE, 2011; Delphi, 2010). The California Air Resources Board (CARB) adopted a rule that since 2007 has not only limited idling to 5 minutes, but also requires automatic shutoff devices. Philadelphia bans the idling of heavy-duty diesel-powered motor vehicles, with exceptions made during cold weather.

FUNDING

The NRC Phase 1 report did not contain a breakdown of the 21CTP budget for idle reduction through 2008 (NRC, 2008). Likewise, the 21CTP budget for idle reduction efforts was not available for FY 2009 and FY 2010 and the FY 2011 President’s Congressional Budget Request (see Table 1-2 in Chapter 1 of this report). Similarly, a budget forecast for meeting the idle reduction goals that extend through 2017 to reduce fuel use and emissions produced by idling engines was not provided to the committee. Therefore, an assessment of the probability of achieving the goals for idle reduction technologies cannot be made at this time. However, as noted in the section, “Goals,” the American Recovery and Reinvestment Act (ARRA) of 2009 did provide funds for idle-reduction related projects.

GOALS

In the NRC Phase 1 report, seven 21CTP goals for engine idle reduction were addressed (NRC, 2008). In its November 15, 2010, presentation to the committee, the 21CTP slightly modified these goals for 2010 and added one new goal. Those goals are presented in bold type in this section. The action items addressing these goals provide a path toward accomplishing the overall goal of the idle reduction portion of the 21CTP. The status of action items addressing each of these goals is discussed in this section.

21CTP Engine Idle Reduction Goal 1. Continue industry/government collaboration to promote the development and deployment of cost-effective technologies for reducing fuel use and emissions due to idling of heavy-duty engines.

For more than a decade, the Department of Energy (DOE) has carried out cooperative research and development (R&D) to characterize and address the reduction of fuel use and emissions during the idling of heavy-duty engines. The NRC (2008) Phase 1 report discussed the R&D work focused on idling reduction technologies. All of the 21CTP partners, both government and industry, have ongoing roles in developing and implementing a coherent program of idling reduction, as described below:

   The DOE analyzes technology needs and performs the appropriate R&D to help make cost-effective technology available for implementation. The results of the analyses enable a systematic comparison of potential strategies, including emission credits, positive incentives, and regulations to install appropriate idle reduction technology.

   The Environmental Protection Agency (EPA) and the Department of Transportation (DOT) have been named to lead the effort in implementation.

Suggested Citation:"6 Engine Idle Reduction." National Research Council. 2012. Review of the 21st Century Truck Partnership, Second Report. Washington, DC: The National Academies Press. doi: 10.17226/13288.
×

   A major goal of the DOD is to reduce the logistical footprint of deployed forces, primarily though savings in fuel consumption.

   The 21CTP industrial partners and their suppliers need to work together to make idle reduction technologies an affordable and cost-effective part of their vehicles’ design, seamlessly integrating their choice of technologies into their products.

   Local, state, and regional air quality agencies have teamed up with the EPA and DOE’s Clean Cities coalitions to form regional collaboratives to address diesel engine emissions, with idling reduction as a major component of their efforts.

21CTP Engine Idle Reduction Goal 2. Expand the current educational programs for truck and bus owners and operators to implement enabling technologies and operational procedures to eliminate unnecessary idling.

The DOE has established or encouraged the following initiatives to educate stakeholders on the benefits of idle reduction and the opportunities to implement technologies and procedures to eliminate unnecessary idling:

   The EPA, through the SmartWay Transport Partnership, has sponsored numerous idle reduction outreach efforts and events, including technical papers, articles, and presentations.

   The DOE Clean Cities Program has sponsored outreach activities to educate Clean Cities’ coordinators and fleet managers about the benefits of idling reductions and the technologies available, through white papers, webcasts, and presentations at various professional meetings. The DOE has produced idle reduction fact sheets and other educational materials.

   Through the Clean Cities Program, the DOE has broadened its involvement in idling reduction to include light- and medium-duty vehicles in addition to heavy-duty vehicles.

   The “National Idling Reduction Network News” is a DOE-sponsored electronic newsletter whose primary distribution each month reaches almost 1,500 readers.

   The DOE has produced idling reduction fact sheets and other educational materials to make drivers and fleet owners aware of reasons not to idle.

   The following DOE and industry publications address idling reduction: Argonne National Laboratory’s Idling: Cruising the Fuel Inefficiency Expressway (ANL, 2009) and Cummins’ Idle Talk: How the Regulations Affect You (Cummins, 2008).

21CTP Engine Idle Reduction Goal 3. Investigate a mix of incentives and regulations to encourage trucks and buses to find other more fuel-efficient and environmentally friendly ways to provide for their power needs at rest.

The ARRA of 2009 has provided the following funding for idle-reduction-related projects (DOE, 2011):

   $65 million for the purchase and installation of idle reduction equipment for on-road diesel vehicles and educational outreach about the benefits of idling reduction (see Goal 2). This project includes APUs, fuel-operated heaters, battery-powered air conditioners, engine block heaters, and engine start-up/shutoff idle control systems and other emission reduction projects, such as engine re-powers (the replacement of an in-use, existing engine with a remanufactured engine or a new engine with lower emissions), replacements, or installation of diesel oxidation catalysts in cases where these projects were bundled with idling reduction projects. Examples of projects funded include the following:4—Installing 163 diesel-fired heaters in the city of Chicago fleets and 155 units in the city of Portland, Oregon, fleets;
—Augmenting state funding for the installation of 562 idle reduction technologies by the Wisconsin Department of Commerce program that competitively awards money for APUs to truckers;
—Providing funding in Nebraska to equip approximately 187 vehicles with EPA-verified idling reduction equipment;
—Adding fuel-fired heaters to school buses in Mississippi, Wisconsin, Minnesota, Michigan, Maryland, South Dakota, and North Dakota; and
—Retrofitting of 180 long-haul trucks with APUs by the Colorado Department of Public Health and Environment 5,6

   $32 million for truck stop electrification (TSE). The funds will provide for the purchase and installation of wayside single-system (no onboard equipment required) and dual-system EPS (DOE, 2011).
—A single-system EPS supplies all needed services through a duct inserted into the cab window. Single-system electrification requires no retrofit on the truck, and therefore minimal upfront cost by the user;
—A dual-system EPS is simply a plug at a parking spot that enables the trucker to tap into the electric power grid to power onboard electrical devices. Dual-system electrification involves installing some combination of an inverter/charger, electric engine block heater, electric fuel heater, and electric heating/cooling device for the cab and sleeper conditioning, and electric idle control on the truck.
Currently, the single system is more widespread.

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4 21CTP response to committee questions from its March 31-April 1, 2011 meeting.

5 Glenn Keller, ANL, “Idle Reduction Accomplishments,” presentation to the committee, November 15, 2010, Washington, D.C.

6 Answers provided by Ken Howden, DOE Office of Vehicle Technologies, to committee question 20(a).

Suggested Citation:"6 Engine Idle Reduction." National Research Council. 2012. Review of the 21st Century Truck Partnership, Second Report. Washington, DC: The National Academies Press. doi: 10.17226/13288.
×

     Approximately 165 electrified parking spaces have been completed to date. Examples of TSE projects that are being funded include the following:

—30 AirDock units on the Maine Turnpike ($1.2 million from EPA ARRA);

—90 Shorepower™ units off Interstate 10 in Arizona;

—14 CabAire units in New Haven, Connecticut; and

—CabAire units on the Pennsylvania Turnpike.7

   Cascade Sierra Solutions has received a $22.2 million grant for a 3-year program known as Shorepower Truck Electrification Project (STEP) for the construction of approximately 1,200 electrified parking spaces at 50 truck stops across the United States. These DOE ARRA funds are matched with private-sector funds. In addition, approximately $10 million is being provided in purchase rebates of up to 20 percent of the cost of idle reduction equipment for users of the STEP network of electrified parking spaces.8

   Grants from the Diesel Emissions Reduction Act (DERA) of 2005 funds have been used at the DOE and EPA to fund a variety of idling reduction projects, such as the following:
—$1.13 million each to Cascade Sierra Solutions, Community Development Transportation Lending Services, and Owner-Operator Independent Drivers Association for revolving loans and low-cost financing for emission- and idling-reduction equipment for trucks (EPA DERA).

The EPA, working with the DOT, states, and private lenders, is developing innovative, market-based, and sustainable funding opportunities, such as low-interest loans through EPA’s SmartWay Program, to replace traditional grants to allow the truck and rail industries to purchase and use idle reduction technologies. Low-interest loans are expected to be a more sustainable incentive than grants, which typically expire after a period of time. Low-interest loans allow truck owners who are unable to make initial investments because of limited capital to pay over time with their fuel savings.

While all of these developments were under way, a major provider of EPSs, IdleAire, filed for bankruptcy in June 2008 and shut down operations. However, by the summer of 2010, Convoy Solutions, LLC, dba IdleAire, began reopening EPS sites. The DOE indicated that all new efforts directed toward EPS are focused on locating the EPSs along major freight corridors.9

The patchwork of anti-idling regulations nationally has been an impediment to broader use of anti-idling measures. The EPA has no legal authority to promulgate anti-idling laws, or any driving time or behavior limits on truck drivers. The EPA’s legal authority rests with promulgating emissions standards to vehicles and engines. (21CTP Response to NRC [2008] Recommendation 6-4; see Appendix C in this report.) However, the regulatory environment is currently changing. Specifically, as noted later in this chapter, the proposed EPA and NHTSA, “Greenhouse Gas Emissions Standards and Fuel Efficiency Standards for Medium- and Heavy-Duty Engines and Vehicles” (EPA/NHTSA, 2010a) contain a provision indicating that, if a manufacturer chooses to use idle reduction technology to meet the standard, then it would require an automatic main engine shutoff after 5 minutes to help ensure that the idle reductions are realized in-use.

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.

21CTP Engine Idle Reduction Goal 4. Facilitate the establishment of consistent electrical codes and standards that apply to both on-board and stationary electrification technologies.

The NRC Phase 1 report on review of the 21CTP described the status of the relevant electrical codes at that time (NRC, 2008). The report focused on changes or additions that were needed in two areas: (1) onboard wiring for the truck and (2) Electrified Parking Spaces. The onboard wiring codes were established in Society of Automotive Engineers (SAE) Standard J2698, finalized and published in 2008 and titled “Primary Single Phase Nominal 120 VAC Wiring Distribution Assembly Design-Truck and Bus.” This SAE standard has addressed the known issues with onboard wiring for the truck identified in the NRC Phase 1 report (NRC, 2008).

The National Electric Code (NEC) Part 626, titled “Electrified Parking Spaces,” was approved in 2008 and addressed these topics: how to plug in, the voltages to supply, and a suggested common plug style. Part 626 clarifies that automobile parking areas are not subject to Part 626, so

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7 Glenn Keller, ANL, “Idle Reduction Accomplishments,” presentation to the committee, November 15, 2010, Washington, D.C.; and answers provided by Ken Howden, DOE Office of Vehicle Technologies, to committee question 20(b).

8 21CTP response to committee questions from its March 31-April 1, 2011, meeting.

9 Glenn Keller, ANL, “Idle Reduction Accomplishments,” presentation to the committee, November 15, 2010, Washington, D.C.

Suggested Citation:"6 Engine Idle Reduction." National Research Council. 2012. Review of the 21st Century Truck Partnership, Second Report. Washington, DC: The National Academies Press. doi: 10.17226/13288.
×

that the SAE J1772 coupler to power a truck is allowed but not required. Part 626 states that the receptacle needs to be a three-wire grounded type and that each truck stop parking spot needs both 208 vac and 120 vac receptacles.10 This NEC standard has addressed the known issues with stationary electrification technologies identified in the NRC Phase 1 report (NRC, 2008).

21CTP Engine Idle Reduction Goal 5. Promote the development and demonstration of cost-effective add-on idling-reduction equipment that meets driver cab comfort needs, has a payback of 2 years or less, and produces fewer emissions of NOx and PM than a truck meeting 2010 emission standards.

The NRC Phase 1 report noted that Webasto Airtop 2000 diesel-fueled cab heaters tested by Schneider National provided a 2.4 percent improvement in fuel economy and a payback of less than 2 years for a fuel price of $2.40/gal. The current list price of the Webasto cab heater is $1,745. Although the DOE has not worked with Schneider since the initial testing program, Schneider has indicated that all 6,000 trucks purchased since 2003 had been retrofitted or factory installed with cab heaters, and 80 percent of its fleet, or 8,000 trucks, were to be retrofitted by the winter of 2007/2008 (Maronde and Slezak, 2006). Webasto and Bergstrom battery-powered cooling systems based on phase- change medium that is charged during normal operation of the truck’s air conditioning system were also evaluated by Schneider National. It was concluded at that time that these cooling systems needed further work, which was not specified, before they could be widely deployed.

DOE’s earlier development of phase-change materials for stand-alone cab cooling had identified deficiencies with this concept. Subsequently, the resolution of these deficiencies has led to the commercial release of the Webasto Blue Cool product. The Blue Cool product was reported to be the first thermal storage APU with shore power connectivity. Cab comfort and electrification are provided without idling. Tests confirmed that Blue Cool provided sufficient cooling under most ambient conditions. The in-cab-mounted air handler delivers chilled air to the bunk for up to 10 hours without consuming any fuel. Blue Cool charges itself while the vehicle is in motion and does not require additional batteries. The electrical load of the circulation pump and fans during cooling is 3.5 to 10 A. Webasto claims that Blue Cool has the shortest return on investment among idle reduction products, although the DOE did not perform testing or analysis to confirm this claim, and sufficient information was not available to determine if this system met the 2-year payback objective (Webasto, 2010). The current price of the Webesto Blue Cool system ranges from $5,295 to $6,595, depending on whether an Airtop 2000 heating unit is also provided.

A team consisting of Espar, Navistar, and Walmart evaluated 20 trucks with Espar (2010) Airtronic bunk heaters, Espar engine preheaters, and Bergstrom Nite battery-powered, electric A/C units, and 5 trucks with ThermoKing Tripac APU systems for heating, cooling, and accessory power. Both configurations provided acceptable performance. Following this evaluation, Walmart retrofitted its entire fleet of 7,000 trucks with Thermo King TriPac units as a result of Walmart’s settlement in 2006 with the EPA for clean air violations related to idling trucks at stores in Connecticut and Massachusetts. The TriPac unit includes a Tier IV-compliant 2-cylinder diesel engine with a diesel particulate filter (DPF) for state of California operation, an alternator for truck battery charging, an A/C unit, and a fuel-fired heater (Thermo King, 2010). The TriPac unit is designed to meet anti-idling and emissions regulations nationwide, including CARB requirements and is claimed to be the sales leader of APU systems in the industry (Thermo King, 2010).

With the tightening of diesel emissions regulations in 2010, some of the diesel APUs are no longer available; others, like the truck diesel engines, have had to be equipped with particulate filters and NOx traps, thereby increasing their costs and making the achievement of the 2-year payback goal more difficult (DOE, 2011).

The military needs APUs to reduce in-field fuel consumption and related logistical costs and to reduce thermal and audible identification signatures during silent watch. APUs are quieter than idling primary engines, and they have a reduced thermal signature, making them less detectable on the battlefield. The U.S. Army Communications-Electronics Research, Development, and Engineering Center (CERDEC) Laboratory is working to demonstrate the feasibility of a diesel engine APU on the M915A5 long-haul tractor. Diesel APUs are being considered since “silent watch” is not a requirement for these trucks. In FY 2008, contracts were awarded to Dewey Electronics and Cummins Power Generation to develop standalone APU/environmental control unit (ECU) prototypes. A contract to Red Dot Corporation is expected to conclude in FY 2011 with the demonstration of two APU/ECU prototypes integrated onto two M915A5 tractor trucks. The resultant system design is projected to save up to 870 gal/yr and to achieve a simple payback period of less than 5 years (assuming fully burdened fuel cost of $15/gal). Reducing fuel use is key because approximately two-thirds of the ground fleet is used to deliver fuel to the other third in the battlefield.

With $500,000 funding from the EPA, the North Carolina State University (NCSU) conducted a 34-month Truck OEM APU Prep Kit Design and Installation Project that was concluded in August 2008 (Tazewell et al., 2008). In this project, Volvo was awarded a contract to develop a Prep Kit to facilitate idle reduction technology installations and demonstrate APUs in at least 20 trucks in the field study and to track idle reduction usage, truck idling, and driver acceptance. The

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10 Answers provided by Ken Howden, DOE Office of Vehicle Technologies, to committee question 19(d), March 1, 2011.

Suggested Citation:"6 Engine Idle Reduction." National Research Council. 2012. Review of the 21st Century Truck Partnership, Second Report. Washington, DC: The National Academies Press. doi: 10.17226/13288.
×

image

FIGURE 6-1 Payback time versus fuel price, by device, used 2,000 hours per year. Acronyms are defined in Appendix I. SOURCE: L. Gaines and D. Santini, Economic Analysis of Commercial Idling Reduction Technologies, Argonne National Laboratory. Available at http://www.transportation.anl.gov/pdfs/TA/372.pdf.

APUs consisted of three components, a Kubota Z482 2-cylinder water-cooled diesel engine, a generator, and a heating, ventilation, and air conditioning (HVAC) system.

The field study was divided into two fleets: the first, Fleet A, had a self-reported annual idling rate of 2,500 hours using Volvo’s largest cabs, with predominately single drivers; the second, Fleet B, had a self-reported annual idling rate of 800 hours using Volvo’s midsize cab with predominately team drivers. The key results from this study were as follows:

   Annual fuel use was reduced for all stops by 22 percent and 5 percent for Fleets A and B, respectively.

   NOx emissions were reduced for all stops by 46 percent and 14 percent for Fleets A and B, respectively.

   Research concluded that 100 percent usage of the APU instead of the base engine could result in a 36 to 47 percent reduction in fuel use, an 80 to 90 percent reduction in NOx emissions, and a 10 to 25 percent reduction in particulate matter (PM) emissions.

The study concluded that driver behavior plays a significant role in determining APU benefits. The data showed that APUs were used by single drivers for an average of 59 percent of the idling time and by team drivers for an average of only 25 percent of the idling time.

The economics of APUs are sensitive to initial APU costs, idling time, actual APU usage, and fuel costs. The NCSU study found engine idle fuel flow rates of approximately 0.6 gal/h instead of the 0.8 gal/h that has been quoted by the EPA and NHTSA, and APU fuel flow rates of approximately 0.32 gal/h instead of the 0.2 gal/h that has been quoted by the EPA and NHTSA (EPA/NHTSA, 2010b, 2011b). Using an initial APU cost of $8,400 and an annual idle time of 2,130 hours and $4.00/gal fuel cost, the simple payback period is 3.5 years.

The Argonne National Laboratory (ANL) has studied payback periods for several idle reduction systems and provided the graph in Figure 6-1 showing the payback time versus fuel price.11 For a $4.00/gal fuel price, the top-of-the-line APU that has an initial cost of $10,000 and is used 2,000 hours per year has a projected payback period of 2.2 years. Other APUs with lower initial costs have a projected payback period of less than 2 years (approximately 1.8 years).

These projections by ANL show shorter payback periods than the projections made by NCSU, because NCSU found that measured base engine idle fuel flow rates were lower than generally assumed and that measured APU fuel

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11 See Gaines and Santini at http://www.transportation.anl.gov/pdfs/TA/372.pdf. 2010.

Suggested Citation:"6 Engine Idle Reduction." National Research Council. 2012. Review of the 21st Century Truck Partnership, Second Report. Washington, DC: The National Academies Press. doi: 10.17226/13288.
×

flow rates were higher than generally assumed. The NCSU report (Tazewell et al., 2008) concluded that APUs generally used more fuel than the published amounts, whereas the 20 newer trucks in this study used less fuel than the commonly published 1 gal/h at idle. The DOE cites ranges for the base engine fuel flow rates between 0.64 and 1.15 gal/h, depending on the idle speed and use of air conditioning. The 21CTP has not as yet determined the representative values for the payback-period calculation, because this would require more study with a wider range of truck models, ages, and fleets.12

The EPA and NHTSA, in the regulatory impact analysis for the “Greenhouse Gas Emissions Standards and Fuel Efficiency Standards for Medium- and Heavy-Duty Engines and Vehicles,” have provided the following values for an APU that can be used to calculate payback period (EPA/NHTSA, 2010b, 2011b):

   Annual idling hours: 1,800 hours;

   Base engine fuel usage: 0.8 gal/h; and

   APU fuel usage: 0.2 gal/h.

The annual fuel savings for an APU were calculated as follows:

Annual Fuel Savings = 1,800 h × (0.8 - 0.2 gal/h)
× $4.00/gal = $4,320/yr.

Therefore, assuming an APU capital cost of $8,400, as before, a simple payback period of approximately 2 years results. At a lower fuel cost of $3.00/gal, the payback period is extended to 2.6 years.

An annual maintenance cost for an APU was not provided by the DOE, so net maintenance cost savings was not included in the calculation of the simple payback period. Net maintenance cost savings, consisting of maintenance cost savings for the main engine (1,800 h/yr × $0.15/h = $270) offset by maintenance cost for the APU, would affect the payback period by approximately 6 percent, depending on the APU maintenance cost and fuel cost.

The DOE informed the committee in March 2011 that it does not currently have plans to address production-level systems not meeting the 2-year payback period, because market forces will likely drive improvements in these systems. For new technology development, the DOE is working with the SuperTruck program participants on various idle reduction concepts and will encourage the participants to consider the potential costs and paybacks of these concepts wherever possible.13

Finding 6-2. A variety of add-on idle reduction systems are commercially available. In earlier studies, a diesel-fuel-fired heater met the 2-year payback goal, but full-function systems (with heating and cooling) had payback periods extending beyond 2 years, owing primarily to high initial cost and less than 100 percent usage during idling. Recent studies of the payback period by the EPA and NHTSA, ANL, and NCSU have provided a range of results related to different assumptions for initial costs, truck engine idle time and APU fuel flow rates, and actual usage times. These studies have projected simple payback periods ranging from 2 to 3.5 years.

Recommendation 6-2. The DOE should conduct a study that includes wide ranges of truck models, ages, and fleets to determine payback periods for the range of commercially available add-on idle reduction systems. The DOE should continue to encourage the deployment of add-on idle reduction systems through communications to manufacturers and end users.

21CTP Engine Idle Reduction Goal (New). Reduce the thermal load of the truck heating, ventilating, and air conditioning (HVAC) system during driver rest periods through implementation of efficient cab insulation systems and low thermal transmission glazing.

A reduction of cabin energy load, through the addition of insulation and window glazing, coupled with controls to reduce peak energy loads, could enable the downsizing of APUs and battery-powered systems to reduce cost and weight while enhancing their performance. To assess the HVAC load reduction potential in truck sleeper cabins, the DOE funded the development of CoolCalc, an analysis tool that allows users to create sleeper cabin models and predict cabin temperatures in different environmental conditions. The main objective of the project was to identify and evaluate design opportunities to reduce the thermal load inside the truck tractor cabs and to enable advanced idle reduction technologies. The DOE has released the software to industry partners.

The DOE also funded the National Renewable Energy Laboratory (NREL) CoolCab project that investigated insulation and reflective glazing to reduce the thermal load and improve the cab’s climate-control efficiency. This project included the thermal testing of Volvo 770 and Kenworth T660 cabs. The results of the Kenworth T660 cab thermal soak test were used to validate the CoolCalc model of the vehicle. Predicted peak soak average air temperature on sunny days was within 0.4°C of the measured value. Development of a CoolCalc model of the Volvo 770 cab is under way. Thermal test results show the heating load in a cab sleeper could be reduced up to 20 percent with high R-value insulation. For FY 2011, the CoolCalc models will be used to quantify the impact of thermal load reduction technologies, such as insulation and reflective glazing, on cooling and heating thermal loads. These results will be used to determine

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12 Answers provided by Ken Howden, DOE Office of Vehicle Technologies, to committee question (25).

13 Answers provided by Ken Howden, DOE Office of Vehicle Technologies, to committee questions, March 1, 2011.

Suggested Citation:"6 Engine Idle Reduction." National Research Council. 2012. Review of the 21st Century Truck Partnership, Second Report. Washington, DC: The National Academies Press. doi: 10.17226/13288.
×

TABLE 6-2 Status of Navistar Auxiliary Power Unit System Versus Program Goals

Parameter Unit Goal Status
Temperature TMC RP-432a Maintain temperature in range for 10 hours Met
Truck idle time Hours per year <200 Met
Idle fuel consumption Gallons per hour <0.25 Met
Emissions Tier 4 Comply Met
Particulate matter Grams per hour <0.2 Met
NOx Grams per hour <25 Met
Price 18 month payback $5,000 Not met
Maintenance Service interval 500 hours Met
5-year life B10 10,000 hours Met

a Specifies minimum 68°F/maximum 78°F sleeper temperatures at 0°F/100°F ambient temperatures.

SOURCE: Data from Casey (2008).

the reduction in sizing of the APU or other idling reduction technology.14

21CTP Engine Idle Reduction Goal 6. Produce a truck with a fully integrated electrically powered truck cab HVAC system to reduce idling-reduction system component duplication, weight, and cost, by 2012.15

The DOE recognizes that costs could be reduced through the complete, nonduplicative integration of idle reduction equipment into the original truck design. Effectiveness in reducing workday idling could be improved by hybridization and by development of systems that reduce idling during creep modes.

To address this goal initially, the DOE funding helped Navistar to complete engineering development to provide the option of ordering factory-installed APUs as original factory-installed equipment (Casey, 2008). Navistar’s idle reduction system had four elements:

   Auxiliary power unit: 2-cylinder water-cooled diesel generator-set generating 6 kW of power at 120 V A/C, purchased from Mechron;

   Electric air conditioner: A stand-alone system mounted in the sleeper compartment;

   Cab and engine heater: Fuel-fired coolant heater purchased from Espar and integrated into the truck’s existing coolant loop; and

   Improved cab insulation.

In addition, Navistar also developed an aftermarket APU wiring accommodation kit as an alternative to its factory-installed APU system.

Navistar had a goal at the beginning of the program to sell 2,000 factory-installed APU idle reduction systems under this program. The goal was not met with the factory-installed APU systems; only 65 units were sold. However, Navistar did sell 2,628 trucks with wiring accommodation kits for aftermarket APUs, indicating that the goal of 2,000 trucks with APUs installed by the end of 2007 was achieved. The goal of 2,000 factory-installed idle reduction systems was exceeded by the 4,325 factory-installed fuel-fired heater systems. However, these factory-installed idle reduction systems did not address the nonduplicative aspect of this goal.

The status of the Navistar APU system versus the goals for the program are shown in Table 6-2. Fuel savings were tracked on five fleet vehicles, and fuel economy increased from 6.38 mpg to 6.99 mpg, providing a 9.6 percent improvement. The Navistar factory-installed APU system did not meet the 18-month payback goal. The cost advantage of aftermarket APU units was likely due to the addition of federal excise tax applied to factory-installed APUs as well as margin added by Navistar for purchasing and installing the unit. However, following this project, the Energy Improvement and Extension Act of 2008, which is a part of the Emergency Economic Stabilization Act of 2008 (Public Law 110-343), modified the Internal Revenue Service (IRS) code and allows for APU units to be exempt from paying the 12 percent federal excise tax. At the conclusion of this project, Navistar announced in March 2008 that it was developing the MaxxPower APU, a 1-cylinder APU to provide a more cost competitive APU offering while meeting California’s 2008 APU emissions requirements.

To address the goal of a fully integrated, electrically powered truck cab HVAC, the DOE, through the ANL, established the Caterpillar More Electric Truck (MET) program

_____________________

14 Answers provided by Ken Howden, DOE Office of Vehicle Technologies, to committee question 19(d), March 1, 2011.

15 “Produce a truck” was interpreted by the committee to mean to design, engineer, and manufacture a truck for sale.

Suggested Citation:"6 Engine Idle Reduction." National Research Council. 2012. Review of the 21st Century Truck Partnership, Second Report. Washington, DC: The National Academies Press. doi: 10.17226/13288.
×

(Lane et al., 2004), which was initiated in 2000 and ended in 2007. The objective of the program was to reduce loads on the engine by using electrically powered accessories including the HVAC, water pump, brake air compressor, oil pump, and cooling fan with revised cooling system (Stone et al., 2004). The results showed a 1.3 percent reduction in fuel consumption on the road due primarily to the electric water pump and electric brake air compressor, and a 2.7 percent reduction in fuel consumption during steady state conditions due to the electric cooling fan with a revised cooling system.

The DOE concurred with Recommendation 6-7 from the NRC (2008) Phase 1 report (see Appendix C)—to continue R&D of the system components used in the More Electric Truck program in order to provide further improvements in idle reduction. In 2007, additional work was anticipated to reduce fuel consumption further in the following areas:

   Mild hybrid energy storage using nickel metal hybrid batteries (NiMH);

   Advanced cooling system components (electric thermostat valve and cooling fan, high-efficiency after-cooler); and

   Decoupling the air compressor from the engine.

The DOE was not able to apply any funding to this program, so as a result, no significant activity toward achieving the 2012 goal of a fully integrated, electrically powered truck cab HVAC system to reduce idling reduction component duplication, weight, and cost has been conducted.16 However, the SuperTruck program is expected to pursue the concept of integrated systems similar to the More Electric Truck program. All three of the SuperTruck program teams, Cummins-Peterbilt, Detroit Diesel, and Navistar, will be addressing idle reduction, as discussed in Chapter 8 of this report.17,18,19

21CTP Engine Idle Reduction Goal 7. Develop and demonstrate viable fuel cell APU systems for military and other users, in the 5-30 kW range, capable of operating on JP-8 fuel with 35 percent efficiency (based on the fuel’s heating value) by 2015.

Delphi’s solid oxide fuel cell (SOFC) APU converts chemical energy in conventional fuels directly into useful electrical power without combustion, resulting in minimal criteria emissions. Delphi has been developing the SOFC since 2000, and is currently working on the fourth generation.20 Cummins plans to use Delphi’s SOFC APU for hotel loads for idle reduction as part of its SuperTruck program. This fuel cell will use ultralow-sulfur diesel fuel. Similarly, Detroit Diesel has also shown a fuel cell APU as a component of its SuperTruck program. Navistar is not planning to use an APU for the SuperTruck program, because a hybrid drive system will be used to charge the large-capacity batteries to provide power for idle reduction functions.

Delphi Corporation and Peterbilt Motors recently announced the demonstration of a Delphi SOFC APU powering a Peterbilt Model 386 truck’s hotel loads.21 The Delphi SOFC APU provided power for the vehicle’s electrical system and air conditioning and maintained the truck’s batteries while the diesel engine was turned off. Recently, Delphi demonstrated the SOFC APU to the public during the November 2010 Hybrid Truck Users Forum (HTUF) conference in Dearborn, Michigan.22

The key subsystems of the SOFC are the SOFC stacks, the fuel reformer, the system controller, and the output power conditioner (Shaffer, 2004). The SOFC stacks operate at a temperature of 750°C, which results in long warm-up times, currently ranging from 2 to 5 hours, with a goal of 1 hour. With the high operating temperature, the exhaust energy is expected to be sufficient to heat the sleeper compartment at close to no-load idle, and possibly the entire passenger cabin when it is used for a break. The electrolyte of the SOFC is yttria-stabilized zirconia, a zirconium-oxide based ceramic.23 The SOFC contains no precious metals. Delphi is currently developing the fourth-generation SOFC stack. The A-Level design APU, currently operating, contains the Gen 3 stack, while the latest B-Level design APU, which contains the Gen 4 stack, was being assembled as of May 2011. The reformer, which uses a proprietary, automotive formulation catalyst containing precious metals, was developed to produce carbon monoxide (CO) and hydrogen (H2) under non-carbon-forming conditions. The output power conditioner converts stack voltage (22 volts for a 30-cell stack module) to the requested output voltage.24

The fuel flow rates and specific fuel consumption values for the SOFC APU in its typical operating mode are shown in Table 6-3 and compared to a two-cylinder diesel APU and to the truck’s diesel engine continuously idling. Previously, the NRC (2010, p. 122) reported that, for carbon-based fuels,

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16 Answers provided by Ken Howden, DOE Office of Vehicle Technologies, to committee questions, March 1, 2011.

17 Donald Stanton, Cummins, “Cummins-Peterbilt SuperTruck Program,” presentation to the committee, November 9, 2010, Washington, D.C.

18 David Kayes, “Detroit Diesel’s Super Truck,” presentation to the committee, September 9, 2010, Washington, D.C..

19 Anthony Cook, Navistar, Inc., “Navistar’s Super Truck Program,” presentation to the committee, September 9, 2010, Washington, D.C.

20 Dan Hennessy, Delphi, “Solid Oxide Fuel Cell Development at Delphi,” presentation to the committee, January 31, 2011, Washington, D.C.

21 Delphi, Peterbilt Test Solid Oxide Fuel Cell APU. Available at http://www.ccjdigital.com/Delphi-peterbilt-test-solid-oxide-fuel-cell. Accessed December 7, 2010.

22 Delphi Demonstrates Solid Oxide Fuel Cell, Showcases Capability to Save Fuel and Cut Emissions During Truck Stops. Available at http://www.Delphi.com/news/pressRelesaes/pr_11_11_001/. Accessed December 7, 2010.

23 Personal communication from Thomas Peffley, Delphi, to committee member W.R. Wade, July 7-8, 2011.

24 Answers provided by Ken Howden, DOE Office of Vehicle Technologies, to committee questions 8(a), 6(a), and 7(a).

Suggested Citation:"6 Engine Idle Reduction." National Research Council. 2012. Review of the 21st Century Truck Partnership, Second Report. Washington, DC: The National Academies Press. doi: 10.17226/13288.
×

TABLE 6-3 Comparison of Fuel Consumption Rates for Various Types of Idle Operation Power Fuel Flow Specific Fuel Output Rate Consumption

Type of Operation at Idle Power Output (kW) Fuel Flow Rate (gal/h) Specific Fuel Consumption (gal/kW-h) References
Engine idle 0.8 EPA/NHTSA (2010b)
Two cylinder diesel APU 5 kW 0.20 to 0.33 0.04 to 0.066 Table 6-4 in this chapter
SOFC APU typical A-Level design 1.5 kW 0.156 0.11

NOTE: Acronyms are defined in Appendix I.

SOURCE: Personal communication, Thomas Peffley, Delphi, July 7-8, 2011.

the fuel-cell-powered APU can achieve the same fuel consumption improvement as that of conventional APUs. More importantly, because of the lower power output of the SOFC APU relative to the diesel APU, the specific fuel consumption (gal/kW-h) of the SOFC APU is approximately twice that of the diesel APU.

Relative to diesel APUs, the SOFC APU provides the following advantages:

   Projected to meet 2010 EPA emissions regulations (even though the reformer produces emissions),

   Very quiet (<60 dBA), and

   Projected longer maintenance intervals and better durability.

The SOFC APU also has a number of issues, including the following:

   Warm-up time of 2 to 5 hours to reach an operating temperature 750°C. Delphi has a goal of 1.5 hours.

   The SOFC APU to be kept operating at idle throughout the workday to maintain temperature and requires an idle fuel flow of approximately 50 percent of the typical operating condition fuel flow. Delphi is evaluating the use of the SOFC APU to power part of the truck electrical loads when the truck is being driven.

   Output of 1.5 kW for an A-Level build design, which is significantly below the DOE’s goal and competitive 5 kW diesel APUs. Delphi is forecasting that a B-Level design will provide 3.0 kW output. Delphi has stated that its SOFC could provide up to 5 kW of power, but it believes that 3.0 kW output is sufficient, based on discussions with truck manufacturers.25

   A 25 percent efficiency (using diesel fuel), which is significantly below the DOE’s goal of 35 percent.

   The continuing need for a desulfurizer bed with a cartridge that requires maintenance every 6 months, even when operated with ultralow-sulfur diesel (ULSD) fuel.

   Weight of 500 lb, which exceeds Delphi’s target of 400 lb and equals that of a diesel APU. On a specific pounds per kilowatt/kW basis, the Delphi SOFC APU is 3.3 times heavier than a diesel APU. Delphi is working on weight reduction of all major subsystems of the SOFC APU and the truck interface and mounting structure.

The 25 percent efficiency of the A-Level design of Delphi’s SOFC APU was obtained at a reported fuel flow rate of 0.156 gal/h of ULSD fuel and 1.39 kW output. The B-Level design APU is expected to improve efficiency to 30 percent, while further improvements are expected to achieve the DOE’s goal of 35 percent.26 Delphi indicated that changing from diesel fuel to JP-8 would lower efficiency because of changes in fuel processing and the fuel’s high sulfur content, although tests on JP-8 have not been conducted.27 Although JP-8 is the standard military fuel, diesel fuel is expected to be used by the APU in commercial truck applications.

Delphi told the committee that it is trying to move the SOFC APU out of the laboratory, but it did not provide a production date. The first B-Level design APU is expected to be installed on a truck that will be used in fleet service in the fall of 2011. Delphi is now focused on the commercial viability of the SOFC APU and is emphasizing the following areas:

   Manufacturability and cost reduction (with the objective of being competitive with a diesel APU; significant cost reductions of the SOFC stack are needed).

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25 Answers provided by Ken Howden, DOE Office of Vehicle Technologies, to committee question 15.

26 The status of the technology and efficiency for SOFCs was based not only on presentations to the committee and answers supplied by the 21CTP to the committee, but also through personal communications between Wallace Wade, committee member, and representatives of Delphi (Dan Hennessy on May 18 and June 23, 2011, and Thomas Peffley on July 7 and 8, 2011).

27 Answers provided by Ken Howden, DOE Office of Vehicle Technologies, to committee question 17(c).

Suggested Citation:"6 Engine Idle Reduction." National Research Council. 2012. Review of the 21st Century Truck Partnership, Second Report. Washington, DC: The National Academies Press. doi: 10.17226/13288.
×

   System-level durability on a test bench for the Gen 4 stack (currently 60 thermal cycles completed; issues are being addressed, particularly seal degradation, prior to continuing to the goal of400 thermal cycles).28

   System-level durability and validation (440 hours and 2,200 miles of operation on a truck have been obtained as of January 2011; extended durability operation on a truck is the next step). Accelerated tests will be run to simulate the durability goals of 28,800 and 1 million miles for heavy-duty truck applications.

Delphi did not provide an estimated cost of the SOFC APU when it met with the committee. However, Delphi later indicated that the life-cycle cost of the SOFC APU (including initial cost, fuel cost, and maintenance costs) is expected to be competitive with “midrange” diesel APUs that are compliant with 2010 emissions standards (Delphi, 2010).

The DOE has provided funding for the development of the SOFC program at Delphi through the Solid State Energy Conversion Alliance (SECA) (Office of Fossil Energy) and through the Office of Energy Efficiency and Renewable Energy (EERE) Fuel Cell Technologies Program. The SOFC program began at Delphi in 2000. After initial studies, the DOE, through the National Energy Technology Laboratory (NETL), entered into a 10-year, $138 million cost-sharing program with Delphi and its partner Battelle to develop and test an SOFC APU that can be mass-produced at low cost for commercial and military applications.29 Early development focused on the use of gasoline, natural gas, and synthetic coal gas before switching to diesel fuel. In addition, Delphi has received government funding that has been used for general system development as well as component development, including the SOFC stack. Most recently, Delphi has received the following SOFC APU-specific awards:30

   Tank-Automotive Research, Development and Engineering Center (TARDEC) Fuel Cell Based Ground Vehicle Auxiliary Power Units ($2.9 million; project completed February 2009);

   DOE Cummins/PACCAR SuperTruck program ($1.0 million, current program); and

   DOE R&D Demonstration of Fuel Cells (Delphi partnered with PACCAR) ($2.4 million, current program).

A battery-operated air-conditioning system is a lower-priced competitor to the Delphi SOFC APU. However, since these systems typically produce 3,000 British thermal units (Btu) to a little over 6,000 Btu cooling, they can maintain comfort in a cabin or sleeper compartment only if it is already cooled by the vehicle’s engine-powered air conditioning. With only 20 to 40 percent of the performance of an APU, they generally are not capable of initial cool-down. If they are used in areas where winter heating is needed, a diesel-fuel-fired heater is a necessary additional cost.

As discussed in the NRC Phase 1 report, the DOD was supporting a variety of companies with various (1) fuel reformers, (2) SOFC, and (3) polymer electrolyte membrane (PEM) fuel cells. At that time it was reported that the DOD had two fuel cell APU programs under way:

   The U.S. Army CERDEC fuel cell APU program was focused on testing and evaluating prototypes. During FY 2007 through FY 2010, several JP-8, ULSD, and DF-2 compatible desulfurization/reformation subsystems were evaluated from the following contractors:31
—IdaTech: Stand-alone desulfurizer and steam reformer integrated with low-temperature PEM fuel cell;
—Altex Technologies: Stand-alone organic sulfur trap with steam reformer and coupled with a high-temperature PEM fuel cell;
—Precision Combustion Inc.: Stand-alone autothermal reformer designed for use with an SOFC; and
—Aspen Products Group: Second-generation desulfurizer integrated with an autothermal reformer for use with an SOFC.

Although feasibility and modest fuel efficiency benefits were demonstrated, the long-term reliability of components and catalyst durability remain challenges. A system development contract with Altex Technologies will conclude in FY 2011, resulting in the delivery of a 5 kWe/10 kWt co-generation system (e = electrical, t = thermal) that is compatible with field kitchen applications.

   The U.S. Army TARDEC fuel cell program had two contracts awarded under a Broad Agency Announcement to Altex Technologies Corporation for a high-temperature PEM fuel cell and United Technologies Research Center for a SOFC.32 The contracts are for a 3-year effort to deliver a fuel cell APU that operates with JP-8 that fits under armor on the Abrams tank in FY 2013.

The U.S. Army TARDEC’s National Automotive Center (NAC) demonstrated a fuel cell APU system in a Peterbilt 385 tractor. SunLine Services Group was the prime contractor, and Southwest Research Institute was the technical integrating contractor (Montemayor, 2006; DOE, 2011).

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28 Answers provided by Ken Howden, DOE Office of Vehicle Technologies, to committee questions 8(a), 6(a), and 7(a).

29 Answers provided by Ken Howden, DOE Office of Vehicle Technologies, to committee questions, March 1, 2011.

30 Answers provided by Ken Howden, DOE Office of Vehicle Technologies, to committee question 5(a).

31 Answers provided by Ken Howden, DOE Office of Vehicle Technologies, to committee question 27(a).

32 Answers provided by Ken Howden, DOE Office of Vehicle Technologies, to committee question 27(b).

Suggested Citation:"6 Engine Idle Reduction." National Research Council. 2012. Review of the 21st Century Truck Partnership, Second Report. Washington, DC: The National Academies Press. doi: 10.17226/13288.
×

Three different configurations of fuel cells were alternatively installed in the truck:

   A 5 kW solid oxide fuel cell from General Dynamics/Acumentrics (which failed after 40 hours),

   Two 1.2 kW Ballard Nexa PEM fuel cells to provide power for the air-conditioning system and the coolant pump, and

   A 20 kW Hydrogenics PEM fuel cell to provide power for the air-conditioning system and radiator cooling fan.

The fuel cells used onboard compressed hydrogen, because liquid fuel reformer systems were not available when this program began in 2000. With the Hydrogenics system installed on the truck, a 13 percent improvement in diesel fuel economy was measured, but the amount of hydrogen used was not available.

The final report for the Sun Transit Agency program stated that a diesel reformer fuel cell hybrid electric truck remains an elusive goal. However, SOFCo, a company specializing in the development of SOFC and fuel processor technology, and Delphi were identified as leading the effort to develop a diesel reformer/fuel cell unit.

Finding 6-3. The Delphi SOFC APU provides several advantages over diesel APUs, but it has significant issues in its current development status, including the following: low efficiency of 25 percent versus the DOE’s goal of 35 percent, a low demonstrated output power of 1.5 kW versus 3.0 kW believed to be sufficient by Delphi, although typical diesel APUs provide 5 kW output, limited demonstrated durability, 2- to 5-hour warm-up time to the 750°C operating temperature, and the need to keep it operating at idle throughout the workday to maintain temperature. 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 the 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. (This recommendation is a follow-on to Recommendation 6-8 in the NRC Phase 1 report.)

Following the reassessment called for in Recommendation 6-3, the DOE will need to determine, if the viability of the SOFC APU is reconfirmed, whether the additional development work required to meet the SOFC APU goals can be contained within the Super Truck program, because the funding for the SOFC APU over the past 10 years of development expires in 2011. Delphi also expects funding from SECA and other contracts with the DOE, DOD, and state sponsors to continue.

SUMMARY OF IDLE REDUCTION TECHNOLOGIES

The EPA’s SmartWay program has evaluated the fuel-saving benefits of various devices through grants, cooperative agreements, emissions and fuel economy testing, demonstration projects, and technical literature review. As a result, the EPA has determined that the following idle reduction technologies provide fuel-saving and/or emissions reducing benefits when used properly in their designed applications:

   Electrified Parking Spaces (truck stop electrification),

   Auxiliary power units and generator sets,

   Fuel operated heaters,

   Battery air-conditioning systems,

   Thermal storage systems, and

   Automatic shut-down/start-up systems.

A listing of specific products that the EPA has verified for each of these categories can be found on the EPA website.33 The listing is quite extensive and illustrates that the commercialization of idle reduction technologies is well under way and has accelerated since the NRC Phase 1 report was published in 2008. The 21CTP has not conducted any detailed analysis of the individual idle reduction products, and so it is not able to comment on the performance of these products.

The functionalities and costs of the idle reduction technologies discussed in this chapter that are under development or in production are summarized in Table 6-4.

EFFECT OF GREENHOUSE GAS EMISSIONS STANDARDS AND FUEL EFFICIENCY STANDARDS

The EPA and NHTSA addressed idle reduction technologies in their final rules for “Greenhouse Gas Emissions Standards and Fuel Efficiency Standards for Medium- and Heavy-Duty Engines and Vehicles” issued on September 15, 2011 (EPA/NHTSA, 2011a). The final rules recognize the following idle reduction technologies (with EPA and NHTSA considering that the baseline Class 8 vehicle consumes 0.8 gal/h of diesel fuel) (EPA/NHTSA, 2010b):

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33Available at http://www.epa.gov/smartway/transport/what-smartway/verified-technologies.htm.

Suggested Citation:"6 Engine Idle Reduction." National Research Council. 2012. Review of the 21st Century Truck Partnership, Second Report. Washington, DC: The National Academies Press. doi: 10.17226/13288.
×

TABLE 6-4 Cab Comfort Technology Summary

System Elements of System Cooling Heating Charge Batteries Fuel Consumption Rate Installed Cost Maintenance Cost/Yr
Nonea Vehicle engine idling (2001 truck) Yes Yes Yes 0.77 gal/h cooling 0.98 gal/h heating $0 $150/30,000 miles for oil changeb
Nonea Vehicle engine idling (2007 truck) Yes Yes Yes 0.53 gal/h heating 0.72 gal/h cooling $0 $150/30,000 miles for oil changeb
Automatic start/stop Vehicle engine idling Yes Yes Yes 0.8 gal/h if on 0.0 gal/h if off $1,200 $150/30,000 miles for oil changeb
Cab bunk heater Diesel fuel burner, heat exchanger, and fan No Yes No 0.04 to 0.06 gal/h $1,300 $110
Evaporative cooler Thermal storage using graphite matrix Yes No No 0.015 gal/h (3.5 to 10 amps from vehicle batteries) $1,800 $100
Battery- powered air-conditioning systems Battery, motor, vapor compression air conditioning components Yes No No 0.15 gal/h $4,000 without battery upgrade $200
Diesel APUa Diesel engine, generator, particulate filter, NOx trap Yes Yes Yes 0.20 to 0.33 gal/h $8,000 (add $1,000 for DPF) $400
Electrified parking space (single system) Heating, cooling module on pedestal connected to window-mounted module (includes communications entertainment) Yes Yes Yes 0 $10 ($9,000 to $16,700 infrastructure cost) $1.00/h -$2.45/h usage cost
Electrified parking space (dual system) Onboard equipment (e.g., inverter/charger, electric heating/cooling device) powered by extension cord Yes Yes Yes 0 ($2,500 to $6,000 infrastructure cost) $1/h usage cost
SOFC APU Solid oxide fuel cell, reformer, output power conditioner Yes Yes Yes 0.2 gal/h $8,000 to $9,000 N/A

NOTE: Acronyms are defined in Appendix I.

a May not be available due to local regulations and/or non-compliance with new 2010 emission regulations. b Possible reduction in overhaul time.

SOURCE: Based on L. Gaines and D. Santini, Economic Analysis of Commercial Idling Reduction Technologies. Available at http://www.transportation.anl.gov/pdfs/TA/372.pdf, and L. Gaines, Which Idling Technologies Are the Best? See references.

   Auxiliary power unit, which powers the truck’s heating, cooling, and electrical system and typically uses 0.2 gal/h of diesel fuel;

   Fuel operated heater, which provides heating services to the truck and typically uses 0.04 gal/h of diesel fuel;

   Battery air-conditioning systems, which provide cooling to the truck; and

   Thermal storage systems, which provide cooling to the truck.

Another alternative involves Electrified Parking Spaces with or without modification to the truck.

The final rules include extended idle reduction technology as an input to the Greenhouse Gas Emission Model (GEM) for Class 8 sleeper cabs. The manufacturer would input a value (see below) based on the idle reduction technology installed in the truck. If a manufacturer chooses to use idle reduction technology to meet the standard, then it would require an automatic main engine shutoff after 5 minutes to help ensure that the idle reductions are realized in-use. However, the agencies are not mandating the use of idle reductions or idle shutdown but rather are allowing their use as one part of a suite of technologies feasible for reducing fuel consumption and meeting the proposed standards.

The EPA’s and NHTSA’s value (0.5 gal/1,000 ton-mile saved) for the idle reduction technologies was determined using an assumption of 1,800 idling hours per year; 125,000 miles traveled; a baseline fuel consumption of 0.8 gal/h; and an APU fuel consumption of 0.2 gal/h ((0.8 - 0.2) gal/h × 1,800 h/(19 tons × 125,000 miles × (1,000 tons)/1,000 tons) = 0.5 gal/1,000 ton-miles saved). Relative to the 2,500 idling hours for single drivers and 800 idling hours for team drivers found in the NCSU (Tazewell et al., 2008) study mentioned earlier, the EPA and NHTSA used 1,800 idling hours per year

Suggested Citation:"6 Engine Idle Reduction." National Research Council. 2012. Review of the 21st Century Truck Partnership, Second Report. Washington, DC: The National Academies Press. doi: 10.17226/13288.
×

for Class 8 trucks with sleeper cabs, which, the committee assumes, may have been a blending of idling hours for single and team drivers. As an example, for a Class 8 mid-roof, sleeper cab with a 2017 proposed standard of 7.2 gal/1,000 ton-miles, idle reduction technology could provide nearly 30 percent of the reduction required to achieve the standard (assuming a total reduction of 1.8 gal/1,000 ton-miles to meet the 7.2 gal/1,000 ton-miles standard, by assuming the standard is a 20 percent reduction [which is within the EPA/NHTSA range of 9 to 23 percent] from the 2010 status, subsequently calculated to be 9.0 gal/1,000 ton-mile). The 0.5 gal/1,000 ton-mile reduction in fuel consumption amounts to a 6 percent reduction in overall fuel consumption (0.5 gal/1,000 ton-mile/9.0 gal/1,000 ton-mile × 100 = 6 percent).

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

RESPONSE TO RECOMMENDATIONS FROM NRC PHASE 1 REPORT

Seven findings and recommendations were made regarding idle reduction technologies in the NRC (2008) Phase 1 report (Findings and Recommendations 6-1 to 6-4 and 6-6 to 6-8) (Finding and Recommendation 6-5 was omitted in the Phase 1 report). The DOE concurred with all of the recommendations except Recommendation 6-4 (see Appendix C in this report), thereby reconfirming the 21CTP engine idle reduction goals that are directed toward substantially reducing energy consumption and exhaust emissions due to heavy-duty-vehicle idling.

Recommendation 6-4 suggested that the EPA renew its efforts to promulgate national anti-idling regulations. The 21CTP commented that the EPA has no legal authority to promulgate anti-idling laws, or any time or behavior limits on truck owners. However, as noted above with respect to Goal 3, the patchwork of anti-idling regulations nationally have been an impediment to the broader use of anti-idling measures and efforts. Finding 6-1 and Recommendation 6-1 in this chapter address this issue by recommending that the EPA and the DOT should work to find incentives for states to promulgate uniform anti-idling regulations.

GOALS FOR FY 2012

In the February 2011 “21CTP Draft White Paper on Idle Reduction” (DOE, 2011), the 21CTP no longer recognizes the previously reviewed goals that extended from the NRC Phase 1 review through 2010. Instead, the 21CTP is recommending the following five goals for FY 2012.

•   21CTP Goal 1 Recommended for FY 2012: Work with OEM truck manufacturers to obtain data on the number of new trucks being ordered with idle reduction options.

•   21CTP Goal 2 Recommended for FY 2012: Conduct a fleet survey to gather data on the amount of in-use idling hours that are accumulated by type of heavy-duty vehicle.

•   21CTP Goal 3 Recommended for FY 2012: Acquire data from the EPA SmartWay Program to measure fuel savings and emissions reductions associated with the various types of idle reduction equipment available.

•   21CTP Goal 4 Recommended for FY 2012: Establish a nationwide multi-mode idle reduction education program.

•   21CTP Goal 5 Recommended for FY 2012: Promote the incorporation of idle reduction equipment on new trucks as fuel saving devices as they are identified through the DOE SuperTruck program.

The 21 CTP stated in the February 2011 idle reduction white paper: “Without funding dedicated to this effort [i.e., the above goals], it is quite difficult, if not impossible, for the 21st Century Truck Partnership to accomplish these goals” (DOE, 2011). The white paper states: “Assuming there is funding, the action items [previously identified as goals through 2010] … lay out a path to accomplishing the stated objective.” In contrast, the committee finds that the new goals, which focus on measuring the usage and benefits of idle reduction and the incorporation of idle reduction technologies on new trucks, are generally not supported by the “action items,” which focus on cost-effective add-on idle reduction technologies; the development of some specific technologies such as electrically powered HVAC systems, cab insulation, and fuel cell APUs; and education programs and incentives to encourage the deployment of cost-effective technologies to reduce fuel use and emissions due to idling.

Finding 6-5. In February 2011, the 21CTP deleted the quantification of the overall goal to reduce fuel use and emissions produced by idling engines. The 21CTP issued five new goals for idle reduction and designated the goals that had been in place through 2010 as “action items.” The new goals are generally not supported by the “action items.” A separate budget for idle reduction for FY 2012 has not been proposed, although idle reduction will be addressed by the SuperTruck program. The 21CTP has stated that, “without

Suggested Citation:"6 Engine Idle Reduction." National Research Council. 2012. Review of the 21st Century Truck Partnership, Second Report. Washington, DC: The National Academies Press. doi: 10.17226/13288.
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funding dedicated to this effort [the idle reduction goals], it is quite difficult, if not impossible, to accomplish these goals” (DOE, 2011).

Recommendation 6-5. The 21CTP should revise its new idle reduction goals to include metrics, funding, and timing for the overall goal of reducing fuel use and emissions produced by idling engines. The associated “action items” should be supportive of these goals.

REFERENCES

American Transportation Research Institute. 2006. Idle Reduction Technology—Fleet Preferences Survey. February.

ANL (Argonne National Laboratory). 2009. Idling, Cruising the Fuel Inefficiency Expressway. Center for Transportation Research. September. Available at http://www1.eere.energy.gov/cleancities/pdfs/idling_reduction_primer.pdf. Accessed October 23.

Casey, C. 2008. Release of Factory-Installed Idle Reduction Systems for International Sleeper Trucks. Final Scientific/Technical Report DE-PS26-05NT42485. International Truck and Engine Corporation. September 5.

Cummins. 2008. Idle Talk: How the New Regulations Affect You. February. Available at http://www.Cumminsnorthwest.com/PDF/IdleTalk.pdf. Accessed October 23, 2011.

Delphi. 2010. Delphi truck fuel-cell APU to hit road in 2010. Automotive Engineering Online. Available at http://sae.org/mags/aei/SEEWC/8222. Accessed December 7, 2010.

DOE (U.S. Department of Energy). 2010. 21CTP Draft White Paper on Idle Reduction. August. Washington, D.C.: Office of Vehicle Technologies.

DOE. 2011. 21CTP Draft White Paper on Idle Reduction. February. Washington, D.C.: Office of Vehicle Technologies.

Espar. 2010. Worldwide Leader in Marine and Vehicle Heaters. Available at http://www.espar.com. Accessed December 7, 2010.

EPA/NHTSA (U.S. Environmental Protection Agency/National Highway Traffic Safety Administration). 2010a. Greenhouse Gas Emissions Standards and Fuel Efficiency Standards for Medium- and Heavy-Duty Engines and Vehicles. Dockets No. EPA-HQ-OAR-2010-0162 and No. NHTSA-2010-0079. October 25. Available at http://www.regulations.gov.

EPA/NHTSA. 2010b. Draft Regulatory Impact Analysis, Proposed Rulemaking to Establish Greenhouse Gas Emissions Standards and Fuel Efficiency Standards for Medium- and Heavy-Duty Engines and Vehicles. EPA-420-D-10-901. October.

EPA/NHTSA. 2011a. Greenhouse Gas Emissions Standards and Fuel Efficiency Standards for Medium- and Heavy-Duty Engines and Vehicles. Federal Register, Vol. 76, No. 179, September 15. Available at http://www.nhtsa.gov/staticfiles/rulemaking/pdf/cafe/2011-20740.pdf.

EPA/NHTSA. 2011b. Final Rulemaking to Establish Greenhouse Gas Emissions Standards and Fuel Efficiency Standards for Medium- and Heavy-Duty Engines and Vehicles. Regulatory Impact Analysis. EPA-420-R-11-901. August.

Gaines, L. Which Idling Reduction Technologies Are the Best? Argonne National Laboratories. Available at http://www.transportation.anl.gov/pdfs/EE/533.pdf.

Gaines, L., and D. Santini. 2006. Economic Analysis of Commercial Idling Reduction Technologies. Argonne National Laboratory. Available at http://www.transportation.anl.gov/pdfs/TA/372.pdf.

Lane, W., S. Diamond, and J. Routbort. 2004. More Electric Truck. FY2004 Annual Report.

Maronde, C., and L. Slezak. 2006. Idle Reduction Demonstration Projects. SAE Commercial Vehicle Engineering Congress and Exhibition. November 1.

Montemayor, A.F. 2006. Phased Introduction of Fuel Cells into a Class 8 Tractor. SWRI Project No. 03983. January 31.

NRC (National Research Council). 2008. Review of the 21st Century Truck Partnership. Washington, D.C.: The National Academies Press.

NRC. 2010. Technologies and Approaches to Reducing the Fuel Consumption of Medium- and Heavy-Duty Vehicles. Washington, D.C.: The National Academies Press.

Shaffer, S. 2004. Development Update on Delphi’s Solid Oxide Fuel Cell System. SECA Review Meeting. Boston, Mass.

Stone, L.M., J.F. Birkel, R.D. Nine, and L.A. Slezak. 2004. Advanced Electric Systems and Aerodynamics for Efficiency Improvements in Heavy Duty Trucks. Final Report. Contractor: Caterpillar, Inc. Contract No. DE-FC26-04NT42189.

Tazewell, A., H.C. Frey, P. Kuo, and J.R. Stone. 2008. EPA Truck OEM APU Prep Kit Design and Installation Project. Final Report. August. North Carolina State University.

Thermo King. 2010. Thermo King Website. Available at http://www.thermoking.com/tripac/. Accessed December 6, 2010.

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In July 2010, the National Research Council (NRC) appointed the Committee to Review the 21st Century Truck Partnership, Phase 2, to conduct an independent review of the 21st Century Truck Partnership (21CTP). The 21CTP is a cooperative research and development (R&D) partnership including four federal agencies-the U.S. Department of Energy (DOE), U.S. Department of Transportation (DOT), U.S. Department of Defense (DOD), and the U.S. Environmental Protection Agency (EPA)-and 15 industrial partners. The purpose of this Partnership 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.

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