4

Medium- and Heavy-Duty Hybrid Vehicles

INTRODUCTION

The 21st Century Truck Partnership (21CTP) focuses on “research and development of advanced heavy-duty hybrid propulsion systems that will reduce energy consumption and pollutant emissions” (DOE, 2011). A heavy-duty hybrid vehicle has an internal combustion engine, an energy storage system, and a means for absorbing or delivering torque from the drivetrain. Hybrid vehicles provide improvements in fuel consumption by several means, including the conversion of kinetic energy into a storable form of energy for later use, the downsizing of the internal combustion engine, engine shutoff, and accessory electrification. A mild hybrid provides idle-stop functionality and regenerative braking. Idle stop-start functionality is made possible by having the electric motor quickly restart the engine. A full hybrid design provides traction capability and higher rates of brake energy regeneration as well as idle-stop functionality.

The two major types of heavy-duty hybrid vehicles discussed in this chapter are hybrid electric vehicles (HEVs), which are the primary focus of the Department of Energy (DOE) in the 21CTP, and hydraulic hybrid vehicles, which are the focus of the Environmental Protection Agency (EPA). In addition to HEVs, similar technologies are being applied to plug-in hybrid electric vehicles (PHEVs) and battery electric vehicles (EVs). Hybrid electric vehicles are considered “a key technology that will help the 21CTP achieve its goals” by enabling manufacturers to achieve reduced fuel consumption and emissions (DOE, 2011). The various electric hybrid architectures have been well described elsewhere (NRC, 2010, 2011). Heavy-duty hybrid electric vehicles provide additional benefits from their unique capability to “creep” in queues and idle without operating the main engine. For Class 8 long-haul trucks, heavy-duty hybrid systems can recharge large-capacity batteries during daytime operation to provide for hotel loads (powering support services for the driver in the truck tractor), eliminating overnight idling of the main engine.

The 21CTP partners work together on technical and commercial programs related to the reduction of fuel consumption by heavy-duty hybrid trucks and the commercialization of these more-fuel-efficient vehicles. In addition to the DOE, the U.S. Department of Defense (DOD), the U.S. Department of Transportation (DOT), EPA, and several original equipment manufacturers (OEMs) and key suppliers, the 21CTP has strategic alliances with the Engine Manufacturers Association (EMA), the Truck Manufacturers Association (TMA), and the Hybrid Truck Users Forum (HTUF). The national laboratories assist the 21CTP in conducting research and development (R&D) involving hybrid technologies. Missing from these partnership alliances are companies in the electric machines, energy storage, and semiconductor-device industries. Such relationships should be fostered through 21CTP R&D programs with industry.

During the 2007-2010 period, the 21CTP project priorities in the area of medium- and heavy-duty hybrid vehicles have been the following:

•   Simulation and modeling,

•   Subsystem R&D, and

•   Vehicle demonstrations.

Progress in addressing each of these priorities is discussed later in this chapter. Programs in these priority areas have been pursued by the DOE through the Argonne National Laboratory (ANL), the National Renewable Energy Laboratory (NREL), and DOE’s Office of Vehicle Technologies; by the DOD through the U.S. Army’s Tank-Automotive Research, Development and Engineering Center (TARDEC); by the DOT through its Federal Transit Agency’s National Fuel Cell Bus Program; and by the EPA through its National Vehicle and Fuel Emissions Laboratory.



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



Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.

OCR for page 59
4 Medium- and Heavy-Duty Hybrid Vehicles INTRODUCTION driver in the truck tractor), eliminating overnight idling of the main engine. The 21st Century Truck Partnership (21CTP) focuses The 21CTP partners work together on technical and com- on “research and development of advanced heavy-duty mercial programs related to the reduction of fuel consump- hybrid propulsion systems that will reduce energy con- tion by heavy-duty hybrid trucks and the commercialization sumption and pollutant emissions” (DOE, 2011). A heavy- of these more-fuel-efficient vehicles. In addition to the DOE, duty hybrid vehicle has an internal combustion engine, the U.S. Department of Defense (DOD), the U.S. Depart- an energy storage system, and a means for absorbing or ment of Transportation (DOT), EPA, and several original delivering torque from the drivetrain. Hybrid vehicles pro - equipment manufacturers (OEMs) and key suppliers, the vide improvements in fuel consumption by several means, 21CTP has strategic alliances with the Engine Manufacturers including the conversion of kinetic energy into a storable Association (EMA), the Truck Manufacturers Association form of energy for later use, the downsizing of the internal (TMA), and the Hybrid Truck Users Forum (HTUF). The combustion engine, engine shutoff, and accessory electrifi- national laboratories assist the 21CTP in conducting research cation. A mild hybrid provides idle-stop functionality and and development (R&D) involving hybrid technologies. regenerative braking. Idle stop-start functionality is made Missing from these partnership alliances are companies in possible by having the electric motor quickly restart the the electric machines, energy storage, and semiconductor- engine. A full hybrid design provides traction capability device industries. Such relationships should be fostered and higher rates of brake energy regeneration as well as through 21CTP R&D programs with industry. idle-stop functionality. During the 2007-2010 period, the 21CTP project priori- The two major types of heavy-duty hybrid vehicles dis- ties in the area of medium- and heavy-duty hybrid vehicles cussed in this chapter are hybrid electric vehicles (HEVs), have been the following: which are the primary focus of the Department of Energy (DOE) in the 21CTP, and hydraulic hybrid vehicles, which • Simulation and modeling, are the focus of the Environmental Protection Agency (EPA). • Subsystem R&D, and In addition to HEVs, similar technologies are being applied • Vehicle demonstrations. to plug-in hybrid electric vehicles (PHEVs) and battery elec- tric vehicles (EVs). Hybrid electric vehicles are considered Progress in addressing each of these priorities is discussed “a key technology that will help the 21CTP achieve its goals” later in this chapter. Programs in these priority areas have by enabling manufacturers to achieve reduced fuel consump- been pursued by the DOE through the Argonne National tion and emissions (DOE, 2011). The various electric hybrid Laboratory (ANL), the National Renewable Energy Labo- architectures have been well described elsewhere (NRC, ratory (NREL), and DOE’s Office of Vehicle Technologies; 2010, 2011). Heavy-duty hybrid electric vehicles provide by the DOD through the U.S. Army’s Tank-Automotive additional benefits from their unique capability to “creep” Research, Development and Engineering Center (TARDEC); in queues and idle without operating the main engine. For by the DOT through its Federal Transit Agency’s National Class 8 long-haul trucks, heavy-duty hybrid systems can Fuel Cell Bus Program; and by the EPA through its National recharge large-capacity batteries during daytime operation Vehicle and Fuel Emissions Laboratory. to provide for hotel loads (powering support services for the 59

OCR for page 59
60 REVIEW OF THE 21ST CENTURY TRUCK PARTNERSHIP, SECOND REPORT Differences Between Heavy-Duty and Light-Duty Hybrids similar. Their weight range is relatively limited (up to Class 2a, under 8,500 lbs GVW), and their driving schedules are Requirements for heavy-duty hybrid vehicles are signifi- characterized by a small number of driving cycles. They are cantly different from those of light-duty (LD) hybrid vehi- manufactured in high volumes, and their expected lifetime cles, and they necessitate unique solutions. In this chapter, mileage is up to 150,000 miles. Hybrid systems for these the term heavy-duty vehicles refers to both medium heavy- vehicles can be manufactured in volumes large enough to duty trucks and heavy-duty trucks, as defined in Figure 1-3 benefit from the economies of scale. in Chapter 1 of this report. Many technologies that apply to Heavy-duty trucks by contrast vary widely in both tare light-duty vehicles do not apply to heavy-duty vehicles. The (empty) and gross weights. Their missions vary from daily heavy-duty truck and light-duty vehicle hybrid technologies runs with frequent stops (e.g., the work of a delivery van) to leverage each other only at the most basic level. Conse- 24-hour–a-day, multiple-day long hauls of tractor-trailers up quently, the 21CTP hybrid program is needed to address the to 200,000 lb GVW. The total fleet of heavy-duty vehicles unique technology needs of heavy-duty vehicles. is 10.99 million, and the average life of a vehicle is up to 1 Unlike LD hybrid vehicles, the broad class of vehicles million miles, resulting in a small market with low turnover comprising the heavy-duty fleet is very diverse and includes and a challenge to making an economic argument for hybrid tractor-trailer, refuse, dump and utility trucks, package deliv- systems generally applicable to the heavy-duty fleet. A con- ery vehicles, buses, and large pickups. These vehicles have ventional hybrid design applied to vehicles whose missions highly differentiated mission profiles, which make it dif- incorporate a lot of stop-and-go driving, such as delivery ficult to establish architectures or performance metrics that vans, urban transit buses, or refuse trucks, has the potential to are commonly applicable to this broad range of heavy-duty be economically sound (i.e., to result in a favorable payback vehicles. Key differences between heavy-duty trucks and period) by providing substantial fuel economy benefits of 20 light-duty vehicles (LDVs) include the following: to 40 percent (17 to 29 percent reduction in fuel consump- tion) (Greszler, 2009).1 A further benefit of hybridization in • Volume: Annual sales volume for heavy-duty trucks is these vehicles is the reduced brake wear and maintenance about 5 percent of that for LDVs, and the former can resulting from regenerative braking. be bought in a thousand times more configurations than In contrast to medium-duty delivery vans, urban transit the latter. buses, and refuse trucks, a heavy-duty, Class 8 long-haul • Buying criteria: Heavy-duty truck buyers prioritize truck makes few stops, maintains a relatively constant speed, reliability and cost of ownership, whereas LDV buyers and requires high power for long periods of grade climbing. prioritize a variety of attributes including cost, func- According to the 21CTP, there are three primary reasons tionality, reliability, performance, and styling. to consider hybridizing a Class 8 long-haul powertrain • Weight: A heavy-duty truck can weigh up to a hundred (Greszler, 2009): times more than an LDV and has peak horsepower up to twice that of LDVs. 1. Reduced engine idle time, through the hybrid energy • Life expectancy and driving cycles: Heavy-duty vehi- storage and use of electric auxiliaries; cles have longer life expectancy and more demanding 2. Reduced fuel use, through the electrification of com- duty cycles than those for LDVs. Heavy-duty vehicles ponents, thereby improving efficiency; and h ave expected lifetime mileages nearly 10 times 3. Reduced fuel usage during cruise, through energy greater than those of LDVs. management with traffic-induced speed variation and in rolling terrain. Driven by these vehicle differences, factors differentiating hybrid systems for heavy-duty vehicles and those for LDVs An additional reason to consider hybridizing a long-haul are power rating, energy storage capacity, number of relevant truck is that, as mentioned above, the large-capacity batter- driving cycles, and economics. Unlike cars and light trucks, ies can be recharged during daytime operation to provide for which are available in only a relatively restricted range of hotel loads so that overnight idling of the main engine can sizes and weights and whose missions have been character- be eliminated. ized by a few standardized driving cycles, heavy-duty trucks span a size range from 8,500 lb (Class 2b) to greater than 33,000 lb (Class 8), with gross vehicle weights (GVWs) Hybrid Technology for the SuperTruck Program of up to 200,000 lb (DOE, 2011). As a result, heavy-duty In FY 2010, the DOE announced the establishment of the hybrid vehicles require high energy storage density, much SuperTruck program, with an overall goal to develop and like an EV, as well as high power density for acceleration demonstrate a 50 percent improvement in freight efficiency and deceleration, like light-duty hybrids. Functional differences between hybrid systems for heavy-duty trucks and those for LDVs result in substantial 1 Answers provided by Ken Howden, DOE Office of Vehicle Technolo- economic differences. Light-duty vehicles are fundamentally gies, to committee questions 9(a) and 42.

OCR for page 59
61 MEDIUM- AND HEAVY-DUTY HYBRID VEHICLES expressed in ton-miles per gallon (33 percent reduction in the proposed fuel consumption standard expressed in gallons per Other simulation studies of the fuel consumption benefit 1,000 ton-miles) for Class 8 long-haul trucks (see Chapter 8). from a variety of hybrid truck configurations have been The three project teams selected for the SuperTruck program conducted and reported (NRC, 2010). The qualification for are Cummins-Peterbilt, Daimler Trucks North America, and these studies is relevant and is repeated here. “While indica- Navistar, Inc. Two of the teams, Daimler and Navistar, are tive of the range of potential benefits, it should be noted that using hybrid technology, with Navistar specifying a dual-mode simulations are carried out under ideal conditions—hence (series/parallel) electric hybrid. The Cummins-Peterbilt team results typically represent best-case scenarios. Real-world is using waste heat recovery (WHR) and a solid oxide fuel cell savings in fuel consumption are likely to be lower, because auxiliary power unit (APU) for idle reduction. All three teams of off-design duty cycles and practical production vehicle are planning to use some electrically driven accessories as part constraints” (NRC, 2010, p. 83). of their hybridization and idle-reduction systems. Limited test results for different duty cycles are avail- able for medium- and heavy-duty hybrid vehicles. Regard- ing one set of results, the EPA conducted tests on a series Impact of Duty Cycle hydraulic hybrid delivery truck over a number of different test duty cycles. The results indicated that the fuel economy Fuel consumption improvements in a heavy-duty hybrid improvements ranged from negligible for the Highway Fuel vehicle are highly dependent on the duty cycle, because the Economy Test (HWFET) to more than 100 percent improve- duty cycle determines the amount of kinetic energy available ment (50 percent reduction in fuel consumption) on the to be recovered, the time available for engine shutoff at idle, Manhattan Bus Cycle.2 and the benefit of the electrification of accessories operat- ing on demand and at constant speed versus operating full Commercialization time at speeds proportional to engine speeds. There are no industry standards yet for heavy-duty hybrid vehicle testing. Hybrid truck technology is currently available in dem- The duty cycle used to measure fuel consumption is typically onstration vehicles as well as commercial vehicles. Heavy- determined by the way that a certain type of vehicle is used duty hybrid electric trucks are commercially available in the targeted application and the creation or selection of an from several manufacturers, including Freightliner/Daimler appropriate cycle based on measured data taken to character- Trucks, International/Navistar, Kenworth, Peterbilt, Ford, ize the vehicle usage. and GMC. Details of the specific models of commercially The Argonne National Laboratory has conducted modeling available heavy-duty hybrid trucks are listed in Appendix studies of the effect of duty cycle on a Class 8 long-haul truck E of this report. Commercially available battery electric with a mild hybrid (50 kW motor and 5 kWh battery) and a trucks are also listed in Appendix E. Heavy-duty hydraulic full hybrid (200 kW motor, a 50 kW starter/generator, and a hybrid trucks are becoming commercially available, with the 25 kWh battery) (NRC, 2010). Both were pre-transmission hydraulic hybrid systems primarily supplied by Eaton, Parker hybrids, that is, hybrids in which the electric drive motor is Hannifin, and Bosch-Rexroth. A summary of the status as of located between the clutch and the transmission, allowing 2009 of the wide variety of hybrid system architectures cur- torque multiplication through the transmission and electric- rently available in the market is provided in Table 4-1. mode-only operation during low power demand. Five drive cycles were evaluated; they included three highway cycles: Hybrid Truck Users Forum (HTUF) HHDDT 65 (Heavy Heavy-Duty Diesel Truck), HHDDT Cruise, and HHDDT High Speed; and two transient/urban The HTUF, which was briefly described in the NRC Phase cycles: HHDDT Transient and UDDS (Urban Dynamic Driv- 1 report (NRC, 2008), is a North American, user-driven ing Schedule) Truck (NRC, 2010). Key observations from this program to speed the commercialization of heavy-duty ANL analysis as described in the National Research Council hybrid and high-efficiency technologies. It is operated by (NRC) report were as follows: CALSTART, a member-supported organization with head- quarters in California and dedicated to supporting a growing • On the highway cycles, fuel savings were less than 10 clean transportation industry, in partnership with the U.S. percent for the full hybrid and less than 5 percent for Army’s National Automotive Center (NAC), with project the mild hybrid. support from the Hewlett Foundation, which makes grants to • Neither hybrid system had enough electrical storage to solve social and environmental problems, and the DOE. The contribute to cruise power demand for any significant HTUF focuses on developing the commercial hybrid industry length of time. • Fuel savings on the transient/urban cycles were greater, although the mild hybrid showed significantly lower 2 John Kargul, EPA, “Clean Automotive Technology, Cost Effective savings than the full hybrid, peaking at 14 percent, Solutions for a Petroleum and Carbon Constrained World,” presentation while the full hybrid showed savings over 40 percent. to a subgroup of the committee, October 26, 2010, Ann Arbor, Michigan.

OCR for page 59
62 REVIEW OF THE 21ST CENTURY TRUCK PARTNERSHIP, SECOND REPORT TABLE 4-1 Hybrid Vehicle Architectures, Their Status as of 2009, and Primary Applications Architecture Technology Status Primary Applications Available now: Eaton, Azure, Volvo Medium-duty/heavy-duty parallel HEV Refuse, urban pickup, and delivery (P&D) Medium-duty/heavy-duty parallel HEV w/e PTO Available now: Eaton, Volvo Bucket truck Parallel gasoline or diesel HEV bus Available now: ISE, Enova, BAE Transit bus Two-mode diesel HEV bus Allison Transit bus Series gasoline or diesel HEV bus Available now: ISE Transit bus Parallel hydraulic hybrid Introduced in 2009: Eaton, Parker Hannifin, Refuse, urban P&D Crane Carrier Series hydraulic hybrid Demo vehicles Refuse, urban P&D Parallel Class 2b Demo vehicles Class 2b pickups and vans Two-mode Class 2b Demo vehicles Class 2b pickups and vans Line-haul dual-mode HEV Demo vehicles Line-haul tractor trailer. Line-haul parallel HEV Demo vehicles Line-haul tractor trailer, motor coach NOTE: Acronyms are provied in Appendix I. See Appendix E, Table E-1, for a list of medium- and heavy-duty vehicle models. SOURCE: TIAX (2009). through increasing user-driven volumes in key platforms to on military bases, (2) identifying and demonstrating hybrid provide the benefits of reduced fuel use and lowered emis- and advanced systems in off-road commercial construction sions. HTUF efforts have accelerated the market “pull” that equipment of use to the military, and (3) assisting with assisted in helping to launch the first production of hybrid identifying and testing commercial-based systems in tactical trucks. vehicle applications. Ten years ago, the U.S. Army and collaborative partner CALSTART launched an initiative to promote hybrid and FUNDING high-efficiency dual-use technologies for the commercial trucking industry and military platforms. The HTUF held The only heavy-duty hybrid truck funding available since its first annual conference at that time. In September 2010, 2007 has been used to conduct in-use and laboratory evalu- the 10th annual HTUF conference was held in Dearborn, ations on hybrid vehicles, mostly delivery trucks and transit Michigan, with 700 attendees. It was the largest national bus applications. None of this funding was for hybrid R&D. conference in the program’s history, signaling the expanding Since 2007, the $1 million to $1.5 million per year for heavy- interest in hybrid trucks and their growing market. During a duty R&D has been focused on aerodynamics, thermal man- panel discussion at this conference, efforts to secure purchase agement, and friction and wear reduction. Although there incentives (through an expansion and extension of the hybrid were no congressional requests for FY 2007 through FY truck tax credit) and R&D funding (through H.R. 3246, the 2010 that specifically targeted 21CTP heavy-duty hybrids, Advanced Vehicle Technology Act) were discussed, but both the work cited above was completed under the DOE’s Office of these efforts have stalled. of Vehicle Technologies, which has included both light-duty The prime role of the HTUF with its military partners and heavy-duty advanced vehicle testing and R&D activities, was to help create the commercial industrial capability to with some of these being hybrid-specific. Project funding support military hybrid advanced technology and vehicle since 2007 is shown in Table 4-2. needs. To date, commercial hybrid use has surpassed that in pure military applications. When HTUF user specifications HYBRID ELECTRIC VEHICLES were developed, they included functionality (stealth mode/ silent watch, power generation) of importance to the military. The various electric hybrid architectures have been well Therefore, most commercial systems can be easily adapted described elsewhere (NRC, 2010, 2011). The three major to military needs. Military hybrid truck adoption has been components of a hybrid system are the electric machines slowed owing to the prolonged and deployed status of the (motor/generator), the electronic controller, and the electric military since September 11, 2001. The military has been in energy storage system (typically a battery or battery/ultraca- a replace-and-repair mode with its vehicles since that time. pacitor combination). In addition, the hybrid powertain sys- The Army has had to delay or halt new vehicle develop- tem includes an internal combustion engine, a transmission ment efforts that included hybrid vehicles. The HTUF is system linking the motor and engine, and electromechani- focusing its near-term efforts on the following areas for the cal controls that determine the electrical and mechanical military: (1) increasing deployments of commercial hybrids power directions and their paths. The electrical machine(s),

OCR for page 59
63 MEDIUM- AND HEAVY-DUTY HYBRID VEHICLES TABLE 4-2 Heavy-Duty Hybrid Funding for The drive unit consists of the motor, controller, and pack- FY2007-FY2010 aging. No R&D work for drive-unit systems technology for heavy-duty hybrid vehicles was funded by the DOE for FY FY 2007 FY 2008 FY 2009 FY 2010 2007 through FY 2010. The NRC Phase 1 report (NRC, 2008) stated that “very little evidence was presented to the HD Simulation and $200,000 $250,000 $200,000 $350,000 Technology Focused committee to substantiate any significant progress made by HEV R&D 21CTP-funded researchers toward achieving the desired reli- HD HEV Fleet $400,000 $450,000 $300,000 $1,500,000 ability target of 15 years design life for the hybrid propulsion Demonstrations equipment. In fairness, the number of prototype heavy-duty Subsystem R&D $0 $0 $0 $0 hybrid trucks currently in the field is very low, making it par- ticularly difficult to gather any meaningful reliability data.” NOTE: Acronyms are defined in Appendix I. The DOE did not discuss the status of costs of the drive-unit SOURCE: Lee Slezak and Kevin Walkowicz, NREL, “Hybrid Team Progress on Past Goals,” presentation to the committee, November 15, system with the present committee. The NRC Phase 1 Report 2010, Washington, D.C. (NRC, 2008) stated that “meeting the aggressive cost target of $50/kW is proving to be one of the most difficult challenges its coupling to the driveline, and the necessary power and for the developers of heavy hybrid propulsion systems.” control electronics are generally referred to as the drive unit. The Advanced Power Electronics and Electric Motors Of all the components, the energy storage system presents (APEEM) program is one of the DOE’s Office of Vehicle the greatest economic challenge for the truck application. Technologies’ two basic building blocks for electric propul- Trucks in stop-and-go driving and with long lives will require sion drive vehicles; it includes power electronics, electric long-life energy storage systems, as identified in the goal for motors, thermal management, and packaging. The Office of energy storage systems discussed in the next section. Vehicle Technologies addresses the needs of both light- and heavy-duty vehicles. A principal objective of the APEEM R &D program is to reduce component and subsystem Goals and Status costs so that a customer can recover the additional cost for The overall goal of the 21CTP for the heavy-duty hybrid advanced electric vehicles in 3 years through fuel savings system is to develop and demonstrate system technologies (DOE, 2010). In addition to cost, APEEM research focuses that deliver substantial reductions in fuel consumption for on components that are significantly smaller, lighter, and both urban start-stop use and for higher mileage applications. more reliable than those of existing systems. The American The top-priority hybrid electric vehicle R&D areas requiring Recovery and Reinvestment Act of 2009 (ARRA) awarded support are the following: $500 million in grants to U.S.-based manufacturers to accel- erate the development of the U.S. manufacturing capacity 1. Drive-unit optimization, for electric drive components. These R&D programs are 2. Drive-unit cost, described in the DOE’s “Multi-Year Program Plan 2011- 3. Energy storage system reliability, 2015” (DOE, 2010, pp. 2.1-20 to 2.1-25). The specific 4. Energy storage system cost, and applicability of these projects to heavy-duty vehicles was 5. The ability to attain fuel-consumption improvements. not provided to the committee. 21 CTP Goal 2: Develop an energy storage system with Three hybrid technology goals for 2012 were established in 2006 by the 21CTP.3 The progress toward achieving 15 years of design life that prioritizes high power rather than high energy, and costs no more than $25/kW peak each of these goals is discussed below. The revised, stretch electric power rating by 2012. goals for heavy-duty hybrids issued by the 21CTP in 2011 are summarized in the section below titled “Revised Goals Issued in 2011.” The energy storage system consists of the battery, its thermal control system, and packaging. No R&D work for 21CTP Goal 1: Develop a new generation of drive unit energy storage technology for heavy-duty hybrid vehicles systems that have higher specific power, lower cost, and was funded by the DOE for FY 2007 through FY 2010. The durability matching the service life of the vehicle. Develop NRC Phase 1 report (NRC, 2008) provided the status of a drive unit that has 15 years of design life and costs no energy storage systems for the light-duty FreedomCAR pro- more than $50/kW by 2012. gram. As noted earlier, heavy-duty hybrids are significantly different from light-duty hybrids. The DOE indicated to the committee that the state-of-the-art energy storage systems are typically rated for 8 years of useful life.4 The DOE did 3 Lee Slezak and Kevin Walkowicz, NREL, “Hybrid Team Progress on Past Goals,” presentation to the committee, November 15, 2010, Washing- 4 Answers ton, D.C. provided by Ken Howden, DOE Office of Vehicle Technolo-

OCR for page 59
64 REVIEW OF THE 21ST CENTURY TRUCK PARTNERSHIP, SECOND REPORT not discuss the status of costs of heavy-duty hybrid energy storage systems with the committee. • Both procurement costs and life–cycle costs, The DOE’s 2010 cost goal for light-duty hybrid energy • Weight and space claim, storage systems is $750 to $900/kWh (nameplate capacity).5 • Life expectancy (in a heavy-duty drive cycle), However, the committee was informed by one manufacturer • Energy and power capacity for a heavy-duty hybrid that the current cost for heavy-duty hybrid energy storage application, systems was approximately $2,000/kWh (nameplate capac- • Suitability for the heavy-duty vehicle environment and ity). Drivers of the increased cost relative to light-duty energy cooling techniques, storage systems are the operating environment (e.g., vibra- • Architecture and modularity, tion) in the truck and lower production volumes over which • Safety and failure modes, tooling, design, and validation costs can be amortized. • Maintainability, Electrical energy storage has improved in the past decade, • Management and equalization electronics and algo- but further gains are required for truck applications. The rithms, and more promising technologies are the nickel metal-hydride • Supplier base for the storage elements. battery, lithium technology batteries, and ultracapacitors. The EV requires a high-energy electrical storage capac - On March 19, 2009, the DOE launched a $2 billion ity for a long driving range. Heavy-duty hybrid vehicles competitive grant program under the ARRA to promote the require high energy storage density, much like an EV, as manufacturing of the batteries and parts for electric vehicles. well as high power density for acceleration and decelera- The objective of these grants is to establish a complete “value tion, like light-duty hybrids. In recent years batteries have chain” for lithium battery manufacturing, from material sup- been the major focus for electrical energy storage for LDVs, ply, to cell production, to pack assembly. Twelve domestic and results provide an opportunity for cross-application to manufacturers are developing battery materials, production medium-duty and heavy-duty hybrid development. Several and recycling capabilities, as shown in Table 4-3. DOE companies (A123 Systems, Hitachi, and Valence Tech- funding for each of the manufacturers is listed in the table. nologies, Inc.) are producing batteries for transit operations. Nine domestic U.S. battery manufacturing facilities for Since 2007 the DOE has funded seven heavy-duty hybrid cell production and for pack assembly, together with total projects. These have all been vehicles with a high level of investment in these facilities, are shown in Table 4-4. The stop-and-go behavior in their mission profiles—for example, committee was not provided with information on the appli- delivery vehicles and school and transit buses. Observed cability of the manufacturing facilities shown in Tables 4-3 and 4-4 to light-duty versus heavy-duty vehicles.7 However, fuel economy improvements for hybrid electric vehicles ranged from 0 to 30 percent (0 to 23 percent reduction in the committee believes that these facilities would be capable fuel consumption), whereas a plug-in hybrid electric school of supplying batteries for medium- and heavy-duty trucks, bus exhibited an improvement up to 57 percent (36 percent although their shock and vibration requirements are more reduction in fuel consumption), but results were inconsistent severe than for LDVs. because of incomplete battery-charging data.6 As with the APEEM program mentioned above, battery Opportunity exists for further fuel consumption reduc - energy storage is one of the DOE’s Office of Vehicle Tech- tions and cost reductions with the development and applica- nologies’ two basic building blocks for electric propulsion tion of components designed specifically for the heavy-duty drive vehicles; it includes a wide range of battery technol- hybrid vehicles. For example, a greater fraction of braking ogy R&D under the U.S. Advanced Battery Consortium energy could be regenerated if the power electronic and (USABC) that addresses the needs of both light- and heavy- energy storage systems were more efficient and able to duty vehicles. The battery R&D is engaged in topics ranging transfer energy at higher powers. Other areas for improve - from fundamental materials research through battery devel- opment and testing and includes the following:8 ment are implementing the system-wide electrification of accessories and increasing the temperature range of opera - tion for lithium batteries. The key challenges identified by • Seventy laboratory and university projects to address the DOE for the heavy-duty hybrid energy storage system the cost, life, and safety of lithium-ion batteries and to are as follows: develop next-generation materials; and gies, to committee question 42. 5 Patrick B. Davis, DOE, “U.S. Department of Energy Vehicle Technolo - 7 James gies Program Overview,” presentation to the committee, September 8, 2010, Miller, DOE, “Status/Prospects for Energy Storage Technology Washington, D.C. Note that these cost goals for electric energy storage are for Medium-Duty and Heavy-Duty Hybrids,” presentation to the committee, different from the peak power cost goal in Goal 2 of $25/kW. January 31, 2011, Washington, D.C. 6 Answers provided by Ken Howden, DOE Office of Vehicle Tech- 8 James Miller, DOE, “Status/Prospects for Energy Storage Technology nologies, to the committee’s written questions to 21CTP representatives, for Medium-Duty and Heavy-Duty Hybrids,” presentation to the committee, Question 9a. January 31, 2011, Washington, D.C.

OCR for page 59
65 MEDIUM- AND HEAVY-DUTY HYBRID VEHICLES TABLE 4-3 Electric-Vehicle Battery Materials, Production, and Recycling Capabilities Being Developed by 12 Domestic Manufacturers, with Amount of Department of Energy Funding Company Location Funding Material Description Production of nickel-cobalt-metal Elyria, OH $50 M Cathode cathode material for Li-ion batteries $70 M Production of nickel-cobalt-metal Midland, MI Cathode cathode material for Li-ion batteries $23 M Production of carbon powder anode Sanborn, NY Anode material for Li-ion batteries $25 M Production of high-temp anode Batesville, AR Anode material for Li-ion batteries $41 M Production of electrolytes Zachary, LA Electrolyte for Li-ion batteries $55 M Production of electrolyte salt Buffalo, NY & Metropolis, IL Electrolyte for Li-ion batteries Production of polymer separator Charlotte, NC $101 M Separator material for lithium-ion batteries $60 M Production of battery-grade lithium Silverpeak, NV & Kings Mtn., NC Lithium carbonate and lithium hydroxide $28 M Production of high-energy density Albany, OR Carbon nano-carbon for ultracapacitors $10 M Manufacturing of precision aluminum Holland, MI Cell Casing casings for cylindrical cells $19 M Hydrothermal recycling of Li-ion Lancaster, OH Recycling batteries JCI Production of battery separators for Lebanon, OR Separator Partner HEVs and EVs SOURCE: James Miller, DOE, “Status/Prospects for Energy Storage Technology for Medium-Duty and Heavy-Duty Hybrids,” presentation to the com - mittee, January 31, 2011, Washington, D.C. 4-1.eps • Thirty-five industry contracts to design, build, and test is supporting a large number of programs addressing issues battery prototype hardware, to optimize materials and ranging from fundamental materials research through battery processing specifications, and to reduce cost. development and testing. Significant progress has been made in developing domestic manufacturing facilities for battery Notable accomplishments made by the USABC battery materials production and recycling, cell production, and pack development partners for light-duty vehicles include the assembly. Although the applicability of these programs to following: heavy-duty applications was not provided to the committee, the committee believes that these developments are supportive • Johnson Controls-SAFT (JCS) is supplying lithium- of the needs of medium- and heavy-duty hybrid applications. ion batteries to BMW and Mercedes for hybrids; 21CTP Goal 3: Develop and demonstrate a heavy hybrid • A123 Systems is supplying batteries to Ford EVs and propulsion technology that achieves a 60% improvement hybrid buses; and in fuel economy (38% reduction in fuel consumption), on • Compact Power/LG Chem is supplying lithium-ion a representative urban driving cycle, while meeting regu- cells to GM for the Chevrolet Volt. lated emissions levels for 2007 and thereafter. Progress in heavy-duty batteries is expected to benefit from the development of light-duty vehicle batteries. No R&D work to reduce the fuel consumption of heavy- duty hybrid vehicles was funded by the DOE for FY 2007 Finding 4-1. Although 2012 has been established as the dead- through FY 2010. However, fleet testing sponsored by the line for 21CTP Goals 1 and 2 for hybrid vehicle technology, DOE has shown that, for “urban-based, start and stop driving it is unlikely that these will be met, because there has been no cycles” (e.g., FedEx route, transit bus, etc.), demonstrations funding for either goal. However, with regard to Goal 2, the in the 20 to 40 percent range (17 to 29 percent reduction in DOE’s Office of Vehicle Technologies’ battery R&D program fuel consumption) have been achieved, based on measured

OCR for page 59
66 REVIEW OF THE 21ST CENTURY TRUCK PARTNERSHIP, SECOND REPORT TABLE 4-4 Nine Domestic Manufacturing Facilities for Battery Cell Production and Pack Assembly and Amount of Total Investment Total Cell Pack Company Location Description Investment Manu. Assembly Holland, MI $600 M Li-Ion: Nickel Metal Cobalt Lebanon, OR Romulus & $500 M Li-Ion: Iron Phosphate Brownstown, MI $302 M St. Clair & Holland, MI Li-Ion: Mixed Manganese $236 M Brownstown, MI Battery Pack Assembly $191 M Jacksonville, FL Li-Ion: Nickel Metal Cobalt Midland, MI $320 M Li-Ion: Manganese Spinel $236 M Indianapolis, IN Li-Ion: Nickel Metal Cobalt $98 M Advanced VRLA and the Ultra Lyon Station, PA Batteries Bristol, TN & $70 M Spiral Wound AGM and Flat Plate Columbus, GA Batteries SOURCE: James Miller, DOE, “Status/Prospects for Energy Storage Technology for Medium-Duty and Heavy-Duty Hybrids,” presentation to the com - 4-2.eps mittee, January 31, 2011, Washington, D.C. fuel usage in the field and testing in the laboratory.9 These Finding 4-2. The DOE did not receive any funding for heavy-duty hybrid R&D in FY 2007 through FY 2010. data are typically determined by measuring how the particu- Consequently, no progress was reported toward the 21CTP’s lar type of vehicle is used in the specific application, and three heavy-duty hybrid goals, primarily focused on R&D, creating or selecting an existing heavy-duty cycle based on for achieving 15 years of design life, achieving cost goals for the measured data characterizing the vehicle usage. There drive-unit systems and energy storage systems, and achiev- are no industry standards yet for heavy-duty hybrid vehicle ing a 60 percent improvement in fuel economy (38 percent testing. The demonstrated fuel economy improvement of 20 reduction in fuel consumption). During this period, the DOE to 40 percent is somewhat reduced from the finding of 35 to made progress in developing heavy-duty hybrid simulations 47 percent improvement (26 to 32 percent reduction in fuel and models and conducting fleet testing and evaluations of consumption) from the NRC Phase 1 report (NRC, 2008), heavy-duty hybrid vehicles. perhaps because of the additional data that were obtained in the intervening time. Recommendation 4-1. The DOE should provide an up-to- DOE vehicle simulation tools have been used to evalu- date status with respect to the heavy-duty hybrid goals. The ate the fuel consumption benefits of advanced technologies DOE should partition the available hybrid funds between to meet the goal of 60 percent improvement in fuel econ- heavy-duty and light-duty hybrid R&D technology to pro- omy (38 percent reduction in fuel consumption). Specific mote the R&D required for the development of heavy-duty advanced technologies and their capabilities of reducing hybrid technologies, because heavy-duty hybrid requirements fuel consumption were not discussed by the DOE, although are significantly different from light-duty requirements. the DOE’s modeling and simulation of heavy-duty hybrid vehicles, discussed in the next section, is focused on iden- tifying technologies for improving the fuel consumption of Simulation and Modeling heavy-duty hybrid vehicles. Modeling and simulation work was begun in 2007 at the Argonne National Laboratory and is currently ongoing using 9 Answers provided by Ken Howden, DOE Office of Vehicle Technologies, the ANL’s simulation tool, Autonomie, to support original to committee’s written questions to 21CTP representatives, Question 42.

OCR for page 59
67 MEDIUM- AND HEAVY-DUTY HYBRID VEHICLES equipment manufacturer (OEM) hybrid activities as well as evaluation, although 21 percent improvement (17 those of government agencies (EPA). State-of-the-art com- percent reduction in fuel consumption) was measured ponent data characterizing heavy-duty vehicle components on a dynamometer test cycle. (engine, transmission, and vehicle aerodynamics) and spe- • Eaton Corporation’s HEV system in a Class 8 tractor cific control strategies have been implemented in Autonomie. in the Coca Cola Enterprise beverage delivery fleet Several applications were validated using test data provided in Miami, Florida (2010)—Chassis dynamometer by the EPA. The close collaborations with OEMs allow the testing showed 0 to 30 percent improvement in fuel national laboratories and industry users to accelerate the economy (0 percent on mostly highway cycle, 30 per- development of heavy-duty hybrid vehicles. cent on urban cycle; 0 to 23 percent reduction in fuel Modeling and simulation work began in 2008 at the consumption). N ational Renewable Energy Laboratory and continues today with simulation and modeling techniques being used The DOT has been involved in the funding of heavy-duty to analyze how medium-duty hybrid vehicles are used in a vehicle hybrids through support of hybrid buses for public broad array of fleet applications. Measured fuel consumption transport. These programs include the following: results were used to validate fuel consumption values derived from dynamic models of the vehicles. A matrix of 120 com- • National Fuel Cell Bus Program—$49 million over 4 ponent sizes, usages, and cost combinations were analyzed years, starting in FY 2006; to minimize fuel consumption and vehicle cost. The results • Transit Investments for Greenhouse Gas and Energy illustrated the dependency of component sizing on the drive Reduction (TIGGER)—$100 million in ARRA funding cycle and daily distance driven. in round 1 and $75 million of discretionary funds in round 2; and • Emission Certification Support for Hybrid Buses— Vehicle Development and Demonstrations carried out at West Virginia University. Hybrid electric drive systems are being tested in heavy- These DOT-supported programs have distinct goals and ben- duty vehicles through the NREL’s fleet testing and evaluation efits that complement the work of other agencies. team. The results provide unbiased, third-party assessment From 2006 to 2010, the DOD has supported heavy-duty of real-world operation and are used to focus future efforts hybrid vehicle programs and has taken leadership in the areas to improve performance and cost-competitiveness. Heavy- of heavy-duty hybrids for combat vehicles and nontactical duty hybrid testing and evaluation project results since 2007 trucks. The U.S. Army, acting through TARDEC and its sub- include the following: ordinate organization, the National Automotive Center, has sponsored heavy-duty hybrid programs. A current program • GM Allison’s HEV transit bus in Seattle, Washington is the Oshkosh ProPulse diesel electric drive system, which (2007)—Improved on-road fuel economy by 27 per- provides electric propulsion power as well as 100 kW of cent (21 percent reduction in fuel consumption) during clean exportable alternating current (ac) power. This technol- a 12-month period. ogy became part of the Heavy Expanded Mobility Tactical • ISE’s series gasoline HEV transit bus in Long Beach, Truck (HEMTT) A3 platform from Oshkosh, which is a California (2008)—Improved on-road fuel economy series-electric hybrid design. Recently, ADA Technologies (based on diesel-equivalent energy content per gallon) announced a $70,000 contract from the U.S. Army for Phase by 8 percent (7 percent reduction in fuel consumption) I research into the development of advanced electrochemical over a 24-month period. ultracapacitor systems for use in hybrid electric vehicles for • BAE’s HEV system in New York City, New York (2009)— high-power military applications (Global and Refining Fuels Improved fuel economy by 28 percent (22 percent reduc- Today, 2011). tion in fuel consumption) over a 12-month period. • Eaton Corporation’s HEV system in the UPS van fleet in Phoenix, Arizona (2009)—Improved fuel economy Progress in Commercializing Hybrid ElectricVehicles by 29 percent (22 percent reduction in fuel consump- tion) over a 12-month period. The committee obtained insight into industry’s progress in commercializing heavy-duty hybrid electric vehicles during a • Enova’s Plug-In HEV system in IC Corporation’s school bus (2009)—Improved fuel economy up to 57 visit to the Eaton Corporation on January 14, 2011. Commer- percent (36 percent reduction in fuel consumption) cialization at Eaton is focused on developing flexible archi- were observed, but results were inconsistent because tectures to accommodate many diverse applications for hybrid of incomplete battery-charging data. systems and developing designs that can provide significant cost reductions through modularization and reusability. • Azure’s hybrid system in the FedEx Los Angeles deliv- ery fleet (2010)—No statistically significant improve- Eaton has been developing hybrid power systems for ment in fuel economy was observed during a 12-month more than a decade, having developed its first prototype in

OCR for page 59
68 REVIEW OF THE 21ST CENTURY TRUCK PARTNERSHIP, SECOND REPORT 2000. In 2002, Eaton began working with FedEx to develop a Transportation Electrification, is funding the development of medium-duty hybrid system. Since that time, Eaton has sold four additional PHEV and EV platforms. More than 1,800 more than 3,500 hybrid systems globally. Although Eaton’s commercial vehicles are being funded by the DOE to aid in largest application for hybrid systems has been for city buses the development and demonstration of PHEVs and full EVs in China, its largest application in the United States has been in fleets around the United States. The objectives of these Class 4 and 5 FedEx delivery vans. Approximately 200 to programs are (1) to accelerate the development of U.S. manu- 300 units have been sold for each class. Eaton’s second larg- facturing capacity for batteries and electric drive components, est application for hybrid systems in the United States has (2) to accelerate the deployment of electric drive vehicles, and been for Class 6 and 7 utility trucks. In these applications, (3) to help reduce costs and meet the 21CTP goals set forth Eaton has acted as the system integrator. One of Eaton’s in 2006. Selected heavy-duty vehicle projects with energy storage being funded by the ARRA include the following:10 challenges has been adapting its hybrid systems to many applications with diverse needs and many niche applications. In addition, there is increased emphasis on all-electric driv - • Electric Vehicles: ing, especially in European cities and for port applications in —Smith Electric Vehicles—An all-electric Class 3 box the United States (see the following section, “Plug-in Hybrid truck is being developed with a 120 kW liquid-cooled and Battery Electric Vehicles”). motor and the option of either a 40 kWh, 80 kWh, or Eaton is developing two different parallel hybrid sys- 120 kWh lithium battery pack. The battery packs are tems: (1) an in-line hybrid system with the engine, motor/ assembled in Kansas by Smith Electric Vehicles using generator, and transmission arranged in-line, and (2) a power modules assembled from Valence Technologies, Inc. take-off (PTO) input hybrid system for a utility truck, which cells manufactured in China. Smith Electric Vehicles has the hybrid drive system connected to the PTO of the received a $32 million award from the DOE to develop transmission and located parallel to the driveshaft. To accom- and deploy 100 of these vehicles. modate the proliferation of applications for hybrid systems, —Navistar—A battery electric Class 2b/Class3 delivery Eaton is developing a flexible hybrid system architecture. A truck is being developed. Navistar received a $39.2 mil- base hybrid drive system common to all applications would lion award to develop and deploy 400 of these vehicles. be interfaced with a flexible architecture extension to pro- Battery packs will be supplied by A123 Systems. vide an energy management system that could be adapted to • Plug-in Hybrid Electric Vehicles: individual, specialized needs. To facilitate this architecture, — Eaton Corporation and Azure Dynamics —The Eaton is developing scalable hybrid drive systems that would DOE awarded the South Coast Air Quality Manage- include scalable motors and batteries for specific applica- ment District $45.4 million, with an additional $45 tions. Power electronics are being integrated into a module million that will come from several sources, including to eliminate cables and simplify packaging in the vehicle $5.5 million from Eaton, to develop and deploy PHEV (Eaton Corporation, 2009). demonstration trucks and shuttle buses over a 3-year Eaton’s pursuit of hybrid vehicle cost reductions is period, starting in August 2009. The 245 utility aerial focused on (1) smaller motors operating at higher speeds, trucks are based on the Ford F550 chassis equipped (2) integration of the hybrid drive system with the transmis- with an Eaton PHEV system. The 35 shuttle buses are sion at the PTO, and (3) flexible architectures with standard based on the Ford E450 chassis equipped with an Azure interfaces. To realize standard interfaces, Eaton indicated Balance PHEV system. Battery packs will be supplied that a committee of the Society of Automotive Engineers is by Compact Power, Inc. Following the delivery of these needed to help drive a standard for this flexible architecture vehicles in the summer of 2011, the demonstration to accelerate the availability of compatible components. period will run for at least 2 years. Additional details of the Eaton program are provided below. —Ford Motor Company—The DOE awarded Ford PLUG-IN HYBRID AND BATTERY ELECTRIC VEHICLES $30 million to deploy 150 PHEVs, including 130 Ford The 21CTP did not have any goals for plug-in hybrid Escape PHEVs and 20 E450 Van PHEVs in partnership electric vehicles or battery electric vehicles. However, much with 15 utilities. The battery packs will be supplied by of the technology for HEVs, including electric machines and Johnson Controls. energy storage systems, is expected to be directly applicable, or nearly so, to the PHEVs and EVs. Eaton provided the following overview of two heavy-duty Plug-in hybrids recharge their energy storage system PHEV programs that were under way during the committee’s through the electric grid, typically at night, when electric- January 2011 visit to Eaton: ity prices and demand are low. The NRC reported in 2010 that commercial medium- and heavy-duty plug-in hybrid 10 James Miller, DOE, “Status/Prospects for Energy Storage Technology vehicles are being delivered in the United States to numerous for Medium-Duty and Heavy-Duty Hybrids,” presentation to the committee, companies (NRC, 2010, p. 74). The DOE, under ARRA- January 31, 2011, Washington, D.C.

OCR for page 59
69 MEDIUM- AND HEAVY-DUTY HYBRID VEHICLES Recommendation 4-2. The DOE should determine what is 1. Ford F550 Diesel PHEV Utility Aerial Truck—Eaton needed for the battery cells and other electric drive compo- has begun its program to develop a Ford F550 diesel nents in the ARRA-Transportation Electrification programs PHEV utility aerial truck with a 15-mile EV range. aimed at development and manufacturing in the United Eaton is the system integrator, and Altec manufac- States, as specified in the objectives of these programs. tures the utility aerial addition for the trucks and will be the manager of the vehicles. The drive unit has a specification of 65 kW and 620 Newton-meters (Nm). HYDRAULIC HYBRID VEHICLES An electric air conditioning (A/C) compressor will be Although the 21CTP did not have any goals for heavy- used. The control strategy will provide the following duty hydraulic hybrid vehicles, the EPA has been conducting modes: (1) maximization of engine-off for job site op- R&D of heavy-duty hydraulic hybrid vehicles since early in erations, (2) range-extended EV mode, and (3) blended the 21CTP program. The EPA has supported Cooperative EV mode. Research and Development Agreements (CRADAs) to help 2. Class 8 PHEV Day Cab Tractor (for port opera- speed the commercialization of federally developed technol- tions)—This program is being conducted for the Texas ogy. Heavy-duty hydraulic hybrid vehicles were mentioned Environmental Research Consortium, whose main briefly in the NRC Phase 1 report (NRC, 2008). The NRC interest is in reducing oxides of nitrogen (NOx) at ship- (2010) report reviewed the EPA’s hydraulic hybrid vehicle ping ports. The Class 8 tractor has a hybrid powertrain, program in greater detail, indicating that the EPA had shifted electrified accessories, and engine stop-start manage- its focus from parallel hydraulic hybrid technology to series ment. The control strategy provides the following hydraulic hybrid technology to realize further improvements modes: (1) EV mode, (2) HEV with engine stop/start in fuel efficiency. management, and (3) conventional HEV/engine-on In contrast to an electric hybrid vehicle utilizing batteries operation. Preliminary results show 44 to 73 percent for energy storage, a hydraulic hybrid vehicle provides high reduction in NOx emissions and 13 to 160 percent specific power, but low specific energy, as shown in Figure increase in fuel economy (12 to 62 percent reduction 4-1. As a result, hydraulic hybrids are effective in providing in fuel consumption) over two test routes—the Eaton short-duration launch assist rather than extended-duration Port Route with a maximum speed of 35 mph and the power assist for cruise conditions. Delivery trucks and refuse City Suburban Heavy Vehicle Route. An electric range trucks with frequent starts and stops are potential applica- of 10.6 miles was achieved at 25 mph and 9.7 miles tions for hydraulic hybrids. at 33 mph for the 74,000 lb vehicle test weight. This program was completed in November 2010. Series Versus Parallel Hydraulic Hybrid In FY 2009, the Technology Acceleration and Deploy- The NRC report on medium- and heavy-duty vehicles ment Activity in the DOE Office of Vehicle Technologies i llustrates the differences between parallel and series provided a $10 million grant to Navistar to fund the develop- hydraulic hybrid systems (NRC, 2010, Figures 4-13 and ment and deployment of the next-generation PHEV school 4-8, respectively). In a parallel hydraulic hybrid system, the bus. Improvements from Navistar’s first-generation design engine and transmission are connected to the differential include electric accessories to enable engine-off operation and drive wheels as in a conventional vehicle. A hydraulic and improved strategies as well as improved energy storage pump-motor unit is geared to the output shaft of the engine approaches. This vehicle is expected to have a 30-mile range and transmission to assist in driving the wheels, or capturing at 45 mph and will use an 80 kWh battery pack. Navistar is braking energy to recharge the hydraulic accumulator tank. currently finalizing the design and build of two PHEV school In contrast, in a series hydraulic hybrid system, there is no bus designs. These vehicles will be evaluated, and one of the mechanical connection between the engine/transmission and designs will be selected for the final build of the vehicles. the differential/drive wheels. A hydraulic pump-motor unit Finding 4-3. More than 1,800 commercial vehicles are is mounted to the output of the engine, and another pump- motor unit is mounted on the input to the differential for the being funded through the ARRA by the DOE to aid in the drive wheels. The respective pump-motor units acting as a development and demonstration of plug-in hybrid electric pump can charge the hydraulic storage tanks using either vehicles and battery electric vehicles in fleets. One of the engine power or deceleration energy from the wheels. The objectives of this program is to develop U.S. manufacturing respective pump-motor units acting as a motor can be used capacity for all-electric drive components (energy storage, to drive the differential for the drive wheels or to restart drive motors, power electronics, etc.). However, in at least the engine. During cruise conditions, the engine-mounted one of these projects, the battery cells are being manufac- pump-motor unit acting as a pump will provide hydraulic tured outside the United States. fluid with some buffering by the hydraulic accumulator system to the pump-motor unit acting as a motor mounted

OCR for page 59
70 REVIEW OF THE 21ST CENTURY TRUCK PARTNERSHIP, SECOND REPORT FIGURE 4-1 Relative performance of energy-storage systems. Acronyms are defined in Appendix I. SOURCE: John Kargul, EPA, “Clean Automotive technology, Cost Effective Solutions for a Petroleum and Carbon Constrained World,” presentation to a subgroup of the committee, October 26, 2010, Ann Arbor, Michigan. 4-3.eps bitmap on the differential for the drive wheels. In a series hydraulic lic fluid to the accumulator compresses the piston into the hybrid, the engine is decoupled from the wheels, enabling nitrogen-filled shell. it to be operated at best-efficiency conditions. Buffering by the hydraulic hybrid accumulator system eliminates the need Fuel Economy Improvements for quick engine transients. The EPA’s program began by investigating parallel hydraulic hybrid systems but switched The potential fuel economy improvements projected for to focus on series hydraulic hybrid systems. parallel and series hydraulic hybrid trucks are shown in Table 4-5 (TIAX, 2009). Transient start-stop driving cycles, such as those of refuse trucks and delivery vans, are required to System Components realize these potential improvements. One of the key components in the series hydraulic hybrid Eaton Corporation is working to improve the performance vehicle is the pump-motor unit. In the EPA’s program, a of parallel hydraulic hybrids in special applications such bent-axis pump-motor unit was developed. The bent-axis as refuse trucks. Eaton’s first-generation hydraulic hybrid, pump-motor unit is a barrel arrangement pump in which also referred to as a hydraulic launch assist (HLA) system, the head of the pump can be pivoted off the centerline of provided 10 to 30 percent improvement (9 to 23 percent the driveshaft. As the yoke angle increases, the pumping reduction in fuel consumption) in fuel economy. The EPA or motoring power increases. A 110 cubic centimeter (cc) showed similar results for its early experimental parallel pump-motor assembly can provide 300 hp at a pressure of 5,000 pounds per square inch (psi). This pump-motor is small enough to be held in one’s hand. TABLE 4-5 Fuel Economy Improvements for Parallel and Two hydraulic storage tanks are required. The high- Series Hydraulic Hybrid Trucks pressure accumulator tank operates between 2,000 and 7,000 Fuel Economy Improvement % (mpg) psi and the low-pressure accumulator tank operates between Type of Truck Fuel Consumption (FC) Reduction (%) 50 and 200 psi. A Class 6 truck would use at least two 22-gal- Parallel hydraulic hybrid 25 to 33% (mpg) lon carbon-fiber accumulator tanks, which are approximately 20 to 25% reduction in FC 5 feet long and 12.5 inches in diameter. Hydraulic accumula- Series hydraulic hybrid 67 to 100% (mpg) tor tanks can be either bladder or piston type. In the bladder 40 to 50% reduction in FC type, adding hydraulic fluid to the accumulator compresses SOURCE: TIAX (2009). the nitrogen-filled bladder. In the piston type, adding hydrau-

OCR for page 59
71 MEDIUM- AND HEAVY-DUTY HYBRID VEHICLES hydraulic hybrid trucks. Eaton’s R&D shows that a parallel • Delivery Vehicles: hydraulic hybrid with an efficient transmission can improve —2008-2011: Fleet testing of 6 pilot vehicles. fuel economy by 35 to 45 percent (26 to 31 percent reduc- —2010-2012: Purchases of 46 early/preproduction tion in fuel consumption) in refuse trucks over the baseline. vehicles announced. Eaton’s next-generation hydraulic hybrid, or HLA, is cur- rently undergoing fleet testing in the refuse industry with The EPA has worked with Parker Hannifin Corporation, about 50 systems. Freightliner, and FedEx in developing a hydraulic hybrid EPA experiments with series hydraulic hybrid trucks delivery vehicle. Currently, Parker Hannifin (in an Auto- have shown fuel economy improvements of 60 to 70 per- car refuse truck), Eaton (in a Peterbilt refuse truck), and cent (38 to 41 percent reduction in fuel consumption) with Bosch-Rexroth (in an American LaFrance refuse truck) are proper matching of hydraulic components and driving the progressing toward full production status with their hydrau- power steering and brake assist off the accumulator pres- lic drive systems. Refuse trucks were a logical application, sure. Although these improvements in fuel economy can be because they already utilize extensive hydraulic systems. obtained with a system tuned for a particular drive cycle, On November 23, 2010, Parker Hannifin Corporation these conditions generally do not exist in the real world. Such announced that it had developed several hydraulic hybrid gains are feasible only when there are almost no electrical technologies that improve the performance of refuse and deliv- loads on the system at idle, very few engine starts, and no ery vehicles to levels that exceed proposed new federal fuel- high-speed travel.11 efficiency and criteria emission standards (Parker Hannifin, 2010). Parker Hannifin stated that its advanced hydraulic hybrid system is unique because it disconnects the engine Progress in Commercializing Hydraulic Hybrid Vehicles from the rear wheels of the vehicles, indicating a series hybrid The EPA initially partnered with Eaton Corporation to configuration. The hydraulic hybrid truck has the potential to develop series hydraulic hybrid technology in a UPS delivery reduce brake maintenance significantly owing to regenerative vehicle. Eaton, which developed a first-generation, parallel braking. Brake life can be extended two to eight times rela- hydraulic hybrid refuse truck, or HLA, has more than 100 tive to the baseline vehicle, which requires three to four brake trucks in the field today. These first-generation vehicles pro- replacements per year, at approximately $2,000 each. This vided a 10 percent improvement in fuel economy (9 percent reduction in brake maintenance can assist in reducing the reduction in fuel consumption) and four times longer brake payback period. Parker Hannifin stated that the technology is life. Eaton’s next-generation HLAs will replace the Allison already in use on 11 refuse vehicles in three South Florida com- transmission with Eaton’s Ultra Shift Plus transmission with munities. UPS and FedEx have become the first companies to the hydraulic unit attached to the transmission’s PTO and order a variation of the technology for use in delivery vehicles, will use hydraulic power to fill in torque during shifts. Eaton scheduled to be on the road in 2011. Parker Hannifin is cur- expects that this next-generation HLA will provide five rently developing further advancements in the technology for times longer brake life and 30 percent better fuel economy use on an advanced bus platform that is targeting a 45 percent (23 percent reduction in fuel consumption) than the baseline reduction in fuel usage over average diesel powertrains. Peterbilt refuse truck. Eaton believes that a refuse truck pro- vides an ideal duty cycle for the hydraulic hybrid vehicle and REGULATORY CONSIDERATIONS estimates that the North American refuse truck market is up to 10,000 vehicles per year. Regulatory considerations for heavy-duty hybrid vehicles Delivery trucks, refuse trucks, yard hustlers, and shuttle include hybrid truck tax credits, credits for fuel-efficiency buses have been the focus of the EPA’s series hydraulic hybrid standards, and emission certification. Each is discussed in program over the past 5+ years. EPA technology transfer the sections that follow. partners are moving to preproduction and/or full production of hydraulic hybrid vehicles in the 2010-2012 time frame. Hybrid Truck Tax Credits The following time lines for these programs was provided by the EPA: Tax credits, which are an important incentive for hybrid vehicles, have expired, but they are described below as back- • Refuse Vehicles: ground information for future consideration of credits (ACEEE, —2008-2011: Fleet testing of 20 pilot vehicles. 2009). The Energy Policy Act of 2005 provided tax credits for —2010-2011: Purchases of 89 early/preproduction heavy-duty hybrid vehicles in the period January 1, 2006, vehicles announced. through December 31, 2009. The credit amount depended on the weight class of the vehicle, its fuel economy relative to a comparable conventional vehicle, and the incremental cost. By 11 Information provided by Mihai Dorobantu, Eaton Corporation, to NRC December 31, 2009, the following 10 manufacturers had certi- staff, James Zucchetto, by e-mail, January 31, 2011.

OCR for page 59
72 REVIEW OF THE 21ST CENTURY TRUCK PARTNERSHIP, SECOND REPORT fied tax credits through the Internal Revenue Service (IRS) for power; over 14,000 lb, the requirement was 15 percent. This at least one heavy-duty hybrid truck or bus model: requirement was to ensure that a qualifying vehicle incorpo- rated substantial hybrid technology. The language of the act Azure Dynamics did not specify the type of hybrid; both electric and hydraulic Freightliner (Daimler Trucks) hybrids, for example, could qualify. Freightliner/Eaton In 2007, the IRS issued guidance setting out procedures International Truck/Eaton for manufacturers to use in certifying a vehicle as an eligible Kenworth/Eaton heavy-duty hybrid, and the amount of the credit for that vehi- cle.12 The credit depended on the hybrid’s fuel economy rela- Navistar/Eaton Navistar/IC Bus tive to that of a comparable conventional vehicle, but there Peterbilt/Eaton was no standard fuel economy test procedure in place for Workhorse/Eaton heavy-duty vehicles. Therefore, the IRS guidance directed Odyne/Navistar manufacturers to assign fuel economies to their vehicles using an approach “substantially similar” to one used by the A hybrid vehicle’s incremental cost was defined in the federal government or the state of California to measure fuel Energy Policy Act of 2005 as the amount by which the economy or emissions. Once the IRS acknowledged a vehicle manufacturer’s suggested retail price of the hybrid vehicle credit, the manufacturer could certify it to purchasers. By exceeded that of a “comparable” vehicle, but the incremental the end of this program, 10 manufacturers were eligible for cost was capped by GVW class, as shown in Table 4-6. credits. Specific models for each manufacturer can be found on the IRS website.13 The percentage of the incremental cost (up to the maxi- mum allowed) that the credit covered was determined by the In February 2011, Senator Debbie Stabenow of Michigan improvement in city fuel economy, as shown in Table 4-7. introduced the Charging America Forward (S. 298) bill, For example, the most efficient 20,000 lb hybrid truck could which calls for an extension of the credits through December receive a credit of $6,000 ($15,000 maximum incremental 31, 2014, and sets new qualifying incremental cost levels cost × 40 percent [hybrid credit for improvement in city fuel for which the purchaser can receive a portion as a tax credit. economy of at least 50 percent]). As of March 2011, this bill had been referred to the Senate Also, under the Energy Policy Act of 2005, the vehicle Finance Committee. had to meet a threshold value of “maximum available power,” a measure of the percentage of total vehicle power available Fuel Efficiency Standards from the rechargeable energy storage system of the vehicle. For a vehicle of 8,500 to 14,000 lb gross vehicle weight, The EPA and the DOT/National Highway Traffic Safety the requirement was 10 percent of the maximum available Administration (NHTSA) introduced proposed standards for greenhouse gas (GHG) emissions standards and fuel efficiency standards for medium- and heavy-duty engines TABLE 4-6 Maximum Incremental Cost of a Hybrid and vehicles on October 25, 2010 (EPA/NHTSA, 2010) and Truck Qualifying for a Tax Credit issued final standards on September 15, 2011 (EPA/NHTSA, 2011). The agencies (a term used throughout this section to Gross Vehicle Weight Maximum Qualified (GVW) Rating Incremental Cost indicate the EPA and DOT/NHTSA) noted that, although the standards are not premised on the use of hybrid powertrains, 8,501 to 14,000 lb $7,500 certain vocational vehicle applications may be suitable can- 14,001 to 26,000 lb $15,000 didates for use of hybrids owing to the greater frequency of > 26,000 lb $30,000 stop-and-go urban operation and their use of power take-off (PTO) systems. As an incentive, the agencies are providing TABLE 4-7 Hybrid Truck Tax Credit as a Function of Fuel credits for the use of hybrid powertrain technology. There is Economy an important distinction between the two types of credits for hybrid vehicles discussed above. The credits provided by the Hybrid Credit as fuel-efficiency standards could be used to meet any of the Percentage of heavy-duty fuel-efficiency standards and are not restricted to Improvement in City Qualified Incremental the averaging set generating the credit. In contrast, the credits Fuel Economy Cost for hybrid vehicles, provided by the U.S. Energy Policy Act At least 30% and under 40% 20% of 2005, were direct tax credits for the purchasers of hybrid (23 to 29% reduction in fuel consumption) At least 40% and under 50% 30% (29 to 33% reduction in fuel consumption) 12 See Internal Revenue Service Notice 2007-46. Available at http://www. At least 50% 40% irs.gov/irb/2007-23_IRB/ar08.html. Accessed December 3, 2010. (At least 33% reduction in fuel consumption) 13 See http://www.irs.gov/businesses/article/0,,id=175456,00.html.

OCR for page 59
73 MEDIUM- AND HEAVY-DUTY HYBRID VEHICLES trucks that deliver improved fuel economy. Because the fuel- tunately, no progress has been reported on this effort by the efficiency standards provide procedures for defining the fuel EPA. Even though the EPA and the NHTSA introduced their economy improvements of hybrid vehicles, these procedures NPRM on October 25, 2010, providing test procedures for could provide a means, in lieu of the previously generated CO2 emissions and fuel consumption for hybrid heavy-duty IRS guidance for truck purchasers, to obtain tax credits, if trucks, a manufacturer still needs a certificate of conformity such credits are reinstated. that the vehicle’s internal combustion engine meets the Two different classes of emissions, GHG emissions and EPA criteria emissions standards for heavy-duty engines, a “criteria pollutants,” are referred to in this section. The procedure that does not recognize hybrid heavy-duty trucks. first class of emissions, GHG emissions (referring primar- Therefore, the potential reduction in emissions with a hybrid ily to CO2), will be controlled by the new GHG emissions heavy-duty truck cannot be recognized, and so reductions standards. The new GHG emissions standards also address in the size or simplification of the emission control system hydrofluorocarbon emissions from air-conditioning systems cannot be considered. and includes nitrous oxide (N2O) and methane (CH4) emis- The California Air Resources Board (CARB) is currently sions standards. The second class of emissions, criteria pol - drafting vehicle-level test procedures for heavy-duty hybrid lutants, refer to hydrocarbons (HC), carbon monoxide (CO), vehicles. California is coordinating this effort with the EPA’s NOx, and particulate matter (PM) exhaust emissions that efforts to establish GHG standards for heavy-duty vehicles. have been regulated by the EPA for many years and require a The CARB’s work is aimed at quantifying the improvement certificate of conformity for engines based on tests conducted in fuel consumption and emissions due to hybridization. on heavy-duty transient engine dynamometers. However, at this time, procedures are in draft form, not final- The agencies’ new fuel consumption and CO2 emissions ized (DOE, 2011). standards are to be tailored to each of three regulatory cat - Finding 4-4. The EPA and the DOT’s National High- egories of heavy-duty vehicles: way Traffic Safety Administration (NHTSA) issued their 1. Heavy-duty pickup trucks and vans, final rules on September 25, 2011, for “Greenhouse Gas 2. Vocational vehicles, and Emissions Standards and Fuel Efficiency Standards for 3. Combination tractors. Medium- and Heavy-Duty Engines and Vehicles.” Although these standards contain test procedures for determining fuel The new rules for the fuel consumption and CO2 standards consumption for heavy-duty hybrid trucks, a manufacturer contain provisions for obtaining credits as an incentive for still needs a certificate of conformity showing that a vehicle’s applying hybrid powetrain technology. The approach to internal combustion engine meets the EPA criteria emission account for the use of a hybrid powertrain when evaluating standards for heavy-duty engines (a procedure that does not compliance with the standards is described in Appendix F. recognize hybrid heavy-duty trucks). The CARB is currently The procedure requires testing heavy-duty pickup trucks drafting vehicle-level test procedures for heavy-duty hybrid and van hybrids on the light-duty federal test procedure vehicles. (FTP) and highway fuel economy test (HWFET) with suitable Recommendation 4-3. As partners of the 21CTP, the EPA adjustments to the test procedures. For vocational vehicles and combination tractors incorporating hybrid powertrains, and DOT/NHTSA should work with the CARB to develop two methods are specified: chassis dynamometer or engine test procedures for the certification process for criteria emis- dynamometer. Each method requires a comparison test (hybrid sions so that the emissions benefits of hybridization will be versus baseline) of the actual physical product (engine, pow- recognized, allowing the reduction in size or simplification ertrain, or vehicle), because the agencies are not aware of ana- of the emission control system of heavy-duty hybrid vehicles lytical models that can assess the technology. The measured to be realized. fuel consumption advantage of a hybrid vehicle versus the baseline is multiplied by the production volume and the use- HYBRID COSTS AND PAYBACK PERIODS ful life to provide the fuel consumption credits for the specific vehicle line that is applied to the manufacturer’s production The NRC report on medium- and heavy-duty vehicles volume-weighted annual fleet average standard. (NRC, 2010) contains extensive information and projections on benefits and costs of hybrid truck systems. Because this information is contained in NRC (2010) in many tables with Emission Certification a variety of other information, a consolidated table present- The NRC Phase 1 report noted the lack of an emissions ing the information exclusively for hybrid truck systems is test and certification procedure for heavy-duty hybrid trucks provided here. The fuel consumption benefit, capital cost, (NRC, 2008). The Phase 1 report noted that the EPA was annual mileage, and typical fuel economy in miles per gallon developing a procedure to measure directly the emissions for technologies projected to be available in the 2015-2020 of complete heavy-duty vehicles, including hybrids. Unfor- time period are shown in Table 4-8. The capital costs are

OCR for page 59
74 REVIEW OF THE 21ST CENTURY TRUCK PARTNERSHIP, SECOND REPORT TABLE 4-8 Hybrid Trucks—Break-even Cost Analysis (Future 2015-2020 Technology) Fuel Payback Consumption Forecasted Period to Benefit Capital Cost Annual Typical Breakeven ($)a Mileageb MPGb Yearsc Referencesd Category Description (%) 18 $9,000 27,500 12.5 7.6 Class 2b Pickups and Vans Parallel electric hybrid Table 6-9 30 $20,000 41,250 9.4 5.1 Class 3 to 6 Straight Box Truck Parallel electric hybrid Table 6-7 13,300e 40 $30,000 9.4 17.7 Class 3 to 6 Bucket Truck Parallel electric hybrid with Table 6-8 electric power takeoff 10 $25,000 137,500 5.75 3.5 Table 6-5 Class 8 Tractor Trailer Truck Mild parallel electric hybrid (not directly comparable with idle reduction because of inclusion of idle reduction feature) 35 $220,000 137,500 6.0 9.1 Urban Transit Bus Series electric hybrid Table 6-16 ($22,000) 0.9 With federal subsidy of incremental cost $39,000f 30 50,000 4.25 3.7 Class 8 Refuse Hauler Parallel hybrid electric Table 4-9 25 $30,000 50,000 4.25 3.4 Class 8 Refuse Hauler Parallel hydraulic hybrid Table 6-10 50 50,000 4.25 Class 8 Refuse Hauler Series hydraulic hybrid N/A N/A Table 4-9 NOTE: The break-even period is calculated on the basis of a fuel cost of $3.00/gal. For a fuel cost of $4.00/gal, the break-even period would be reduced by 25 percent. aCosts for 2015-2020 are forecast to be reduced up to 47% from 2013 to 2015 costs. bAverage values of ranges from NRC (2010), Table 2-1. cBreakeven Time = Capital Cost/(Annual Mileage/MPG × % Improvement × $/gal). dTables 6-5 through 6-16 provide future costs for 2015-2020. All tables are in NRC (2010). eNRC (2010), page 138. fNRC (2010), page 141. projections for 2015-2020 contained in NRC (2010). Using borne by the vehicles’ operators” (DOE, 2011). The 21CTP this consolidated information, a simple calculation of the further stated, “HD [heavy duty] hybrid technology is far payback period to break even, defined as the time to achieve from mature.… Many of today’s HD hybrid vehicles have fuel cost savings equal to the initial capital cost of the hybrid used components that are commercially available but were system, was made assuming a $3.00/gal fuel cost.14 Mainte- not designed or optimized for on-road HD hybrid vehicles. nance costs and discount rates were not included. The results Some HD hybrid components cannot be found elsewhere are also shown in Table 4-8. It is important to note that the and must be custom designed for the application. These will capital costs listed in Table 4-8 are forecasted to be reduced be costly due to low production volumes that have not justi- by up to 47 percent from the 2013-2015 costs, which, in fied the development of high volume manufacturing tools turn, are expected to be lower than current costs for hybrid and processes to produce them economically.” A very large systems. Thus, the capital costs shown are forecasts contain- investment is needed by the developers of the heavy-duty ing reductions of well over 47 percent from current costs. hybrids, the engine manufacturers, and the truck manufac- The 21CTP acknowledges that current break-even times turers to fully develop and implement the technologies in without subsidies, based on current costs and fuel consump- commercial vehicles. The capital costs shown in Table 4-8 tion improvements, are typically twice as long as the 5 years reflect the significant reductions that will be required for that fleets normally require for a return on investment in new HEV systems to become commercially viable. hardware for cost savings. The 21CTP stated that “heavy- Fuel economy improvements of 20 to 40 percent (17 to 29 hybrid technology for commercial trucks and buses needs percent reduction in fuel consumption) have been achieved significant research and development (R&D) before it will be for hybrid trucks over urban-based, start-and-stop driving ready for widespread commercialization at prices that can be cycles. DOE vehicle simulation tools are currently being used to evaluate fuel consumption benefits of advanced technologies to meet the goal of 60 percent improvement in 14 For a fuel cost of $4.00/gal, the breakeven period would be reduced fuel economy (38 percent reduction in fuel consumption). in length by 25 percent.

OCR for page 59
75 MEDIUM- AND HEAVY-DUTY HYBRID VEHICLES By using these forecasted capital costs, most of the tech- —Power density for some motor designs today is at nologies listed in Table 4-8 achieve payback, or break even, approximately 0.5 kW/kg. The objective is to nearly within approximately 5 years, except for the Class 2b pickups double the power density to approximately 1 kW/kg. A and vans, Class 3 to 6 bucket trucks, and transit buses without cost target of $50/kW by 2016 has been established. the 90 percent federal subsidy for the hybrid system incre- —Motors and generators have efficiencies typically at mental cost. The Class 2b pickups and vans need to achieve approximately 94 percent today. The objective is 96 to greater fuel consumption improvements and/or capital cost 97 percent by 2016. reductions to achieve payback in 5 years. The Class 3 to 6 —Demonstrate a nonpermanent magnet motor technology bucket trucks have exceptionally low mileage that extends in a commercial vehicle application that would equal or the payback period well beyond 5 years. No remedy for this meet current hybrid system requirements by 2013. shortfall appears to be available at this time. The continued ° Permanent magnet motors are used in several hybrid application of hybrid technology to transit buses will require systems today. Concern is increasing that higher the continuation of federal subsidies. hybrid volumes will create significantly higher demands for rare-earth magnet material that is pre- Finding 4-5. The 21CTP acknowledges that current heavy- dominantly supplied by China. The development of duty hybrid vehicle break-even times, without subsidies, based alternate motor designs that do not depend on a com- on current costs and fuel consumption improvements, are typi- modity supplied primarily by a single foreign power cally twice as long as the 5 years that fleets normally require is deemed to be in the best interests of the United for a return on investment on new hardware for cost savings. States. Heavy-duty hybrid components tend to be costly because they are not designed or optimized for the application and are Summary of Revised Heavy-Duty Hybrids Goal 2—Inverter produced in low volumes. Fuel-economy improvements of Design/Power Electronics: Develop technologies that will heavy-duty hybrid vehicles have not achieved the 60 percent improve the cycle life of critical components within the improvement goal (38 percent reduction in fuel consumption). inverter and other power electronics within the hybrid system. Recommendation 4-4. Dual paths should be pursued to —Develop an improved switching device (insulated gate achieve a break-even time of 5 years for heavy-duty hybrid bipolar transistors [IGBTs] or other) that has a broader vehicles. First, the DOE should use its vehicle simulation operating temperature range higher than today’s 50°C tools to determine the advanced technologies needed to limit and offers improved system life and durability. meet the goal of 60 percent improvement in fuel economy Develop this improved switching system and demon- (38 percent reduction in fuel consumption), from the current strate benefits by 2016. status of 20 to 40 percent improvement (17 to 29 percent ° IGBTs are today one of the main components of the reduction in fuel consumption) and initiate R&D programs to inverters used in heavy-duty hybrid systems. Their develop these technologies. Second, manufacturers should be cycle life is limited owing to thermal expansion and encouraged to explore modular, flexible designs, which could contraction that occurs with varying power transmis- yield higher production volumes and thus achieve significant sion levels, especially at the IBGT-to-device package reductions in capital costs of hybrid systems. interface. In addition, the allowable temperature range of these devices is limited, with recommenda- tions to maintain operating temperatures below 50°C. REVISED GOALS ISSUED IN 2011 Technology developments focused on these areas In February 2011, the 21CTP issued revised stretch goals will improve system life, simplify cooling require- for heavy-duty hybrids; they are similar to the goals provided ments, and drive down total life–cycle cost. to the committee in November 2010, but the revised goals —By 2016, reduce the overall weight of inverter designs provide more background and/or greater specificity. These by 20 percent through higher efficiency of switching revised stretch goals are summarized below; the complete devices with higher operating temperatures and poten- version is available in the February 28, 2011, Hybrid Propul - tial integration with engine cooling systems. sion White Paper (DOE, 2011). Summary of Revised Heavy-Duty Hybrids Goal 3—Energy Storage Systems: Develop an energy storage system with 15 Summary of Revised Heavy-Duty Hybrids Goal 1—Electric Machines: Develop advanced motor technology that will years of design life, a broader allowable temperature operat- deliver electric machines with improved durability, lower ing range, improved power density and energy density, and cost, better power density, and alternatives to rare-earth significantly lower cost. permanent magnets. —Develop a system that can provide a cycle life of 5,000 —Greater than 1 million miles (Class 8 line-haul applica- full cycles, which should achieve the target of 1 million tion) or 15 years of life (vocational applications). miles (on highway) or 15 years (vocational). Current

OCR for page 59
76 REVIEW OF THE 21ST CENTURY TRUCK PARTNERSHIP, SECOND REPORT state-of-the art energy storage systems are typically achieve significant reductions in parasitic losses by rated for 8 years of life. powering them “on demand.” —Expand the acceptable operating temperature range for —Targeted availability of such improved accessories: lithium-ion batteries, currently at 0 to 55°C, by 2017. 2016. —Develop battery technologies that will significantly increase power and energy densities. Comments on New Hybrid Goals —Proposed cost targets: ° $45/kW and/or $500/kWh for an energy battery by Some of the metrics from the three 2007-2010 goals dis- 2017; cussed earlier in this chapter have been carried over to these ° $40/kW and/or $300/kWh for a power battery by revised new goals. Specifically, 2020; and ° By 2016, the cost of the overall battery pack should • The new revised Goal 1 for electric machines carries over not exceed the cost of the cells themselves by more the 15-year design life and cost of no more than $50/kW than 20 percent. for the drive-unit system from the 2006 Goal 1. —Establish an “end-of-life” strategy for advanced bat - • The new revised Goal 3 for energy storage systems car- teries and provide the necessary funding related to ries over the 15-year design life for the energy storage either the remanufacturing or recycling of batteries systems. However, the revised Goal 3 specifies a higher by 2017. cost of $40/kW peak electric power, whereas the 2006 Goal 2 specified a lower cost of no more than $25/kW peak electric power. Summary of Revised Heavy-Duty Hybrids Goal 4—Hybrid System Optimization, Medium Duty: To develop and dem- • The new revised Goal 5 for Hybrid System Optimiza- onstrate medium-duty hybrid system technology that can tion, Heavy Duty, specifies a stretch goal of 60 percent deliver substantial increases in fuel economy, beyond what improvement in fuel economy (38 percent reduction is available with today’s systems. in fuel consumption), which is the same as the 2006 —Potential applications for demonstration include medium- Goal 3. duty shuttle buses, vocational trucks, or on/off highway medium-duty work trucks. The committee agrees with the white paper (DOE, 2011) —A vehicle demonstration program that provides a plat- that these goals are indeed “stretch goals.” They appear to form for developing these medium-duty technologies be reasonable technical goals, although the 21CTP did not (similar to the SuperTruck program for heavy-duty provide the rationale for developing them. The cost and technologies) is one potential approach, with develop- design-life objectives in the 2006 goals had been identi- ment and demonstrations to be completed by 2017. fied earlier by the 21CTP as necessary for achieving com- mercially viable heavy-duty hybrid vehicles. Although the Summary of Revised Heavy-Duty Hybrids Goal 5—Hybrid 21CTP did not provide specific plans for achieving the six System Optimization, Heavy Duty: An overarching goal is to new revised goals, a significant budget is expected to be develop and demonstrate heavy-duty hybrid system technol- required through the target dates specified in the goals. Such ogy that can deliver substantial increases in fuel economy. a significant budget would require a significant increase from —For urban, heavy start-and-stop driving cycles, a stretch the zero budget for heavy-duty hybrid R&D over the past 3 goal of 60 percent (38 percent reduction in fuel con- years (FY 2007 to FY 2010). sumption) has been identified. —For regional haul and line-haul applications, the per- Finding 4-6. Six new stretch technical goals have been centage improvements would be more modest, with a established by the 21CTP for heavy-duty hybrid vehicles. stretch goal of 25 percent (20 percent reduction in fuel The committee agrees with the 21CTP that these are indeed consumption). stretch goals. Specific plans for achieving these new goals, —Additional review and development need to be consid- some of which were carried over from the previous three goals ered for those vehicles that would possess alternative that had been set for hybrids, were not provided to the com- anti-idling devices that could be provided without mittee. Nor was the rationale provided for these new goals, additional infrastructure changes. although they are appropriately focused on fuel consumption reductions, cost reduction, and a 15-year design life for the Summary of Revised Heavy-Duty Hybrids Goal 6—Electri- technologies. They appear to be reasonable technical goals. fied Power Accessories: Develop robust, durable, efficient The cost and design life objectives in the previous goals had electric power accessories for use with medium- and heavy- been identified earlier by the 21CTP as being necessary for duty hybrid systems. achieving commercially viable heavy-duty hybrid vehicles. —Electrifying accessories such as power steering, air It is expected that a significant budget would be required compressors, and air-conditioning compressors can through the target dates specified in the new goals, and a sig-

OCR for page 59
77 MEDIUM- AND HEAVY-DUTY HYBRID VEHICLES REFERENCES nificant increase from the zero budget for heavy-duty hybrid R&D over the past 3 years would be required. ACEEE (American Council for Energy-Efficient Economy). 2009. Tax Credits for Heavy-Duty Hybrids. Available at http://www.aceee.org/ Recommendation 4-5. The 21CTP should establish plans blog/2009/01/tax-credits-heavy-duty-hybrids. Accessed December 1, 2010. and develop realistic budgets for accomplishing the six new DOE (U.S. Department of Energy). 2010. Multi-Year Program Plan 2011- stretch goals for heavy-duty hybrid vehicles in accordance 2015. Washington, D.C.: Office of Vehicle Technologies, December. with the committee’s findings, explain the rationale behind DOE. 2011. Hybrid Propulsion White Paper, February 28, 2011. Submitted the new goals, and provide the current status of the applicable by the DOE Office of Vehicle Technologies to the committee on behalf technology for each of the goals so that the magnitude of the of the 21st Century Truck Partnership. Eaton Corporation. 2009. Hybrid Solutions for MD Commercial Vehicles. tasks for each can be assessed. ERC Symposium, University of Wisconsin, Madison, June 10, 2009. EPA/NHTSA (U.S. Environmental Protection Agency/National Highway RESPONSE TO RECOMMENDATIONS IN NRC Traffic Safety Administration). 2010. Greenhouse Gas Emissions Standards and Fuel Efficiency Standards for Medium- and Heavy-Duty PHASE 1 REPORT Engines and Vehicles. Dockets No. EPA-HQ-OAR-2010-0162 and No. NHTSA-2010-0079. October 25. Available at http://www.regulations. The DOE concurs with the recommendations regarding gov. hybrid powertrains made in the NRC Phase 1 report (see EPA/NHTSA. 2011. Greenhouse Gas Emissions Standards and Fuel Effi- Recommendations 4-1 through 4-9 in NRC, 2008). In the ciency Standards for Medium- and Heavy-Duty Engines and Vehicles. energy storage area, the DOE recognizes that current light- Federal Register, Vol. 76, No. 179, September 15. Available at http:// duty battery work may not necessarily apply to heavy-duty www.nhtsa.gov/staticfiles/rulemaking/pdf/cafe/2011-20740.pdf. Global Refining & Fuels Today. 2011. ADA Technologies Receives US$70K applications. A DOE-sponsored meeting on energy storage, for R&D from U.S. Army. February 8, 2011, Vol. 3, Issue 25. Available held in January 2011, provided a crosscut of light-duty/ a t http://www.worldfuels.com/newsletters/Global-Refining-Fuels- heavy-duty work (see Appendix C in this volume, presenting Today/3/25/. the 21CTP Response to Finding 4-2 and Recommendation Greszler, A. 2009. Presentation by Anthony Greszler to the House Commit- 4-2 on hybrids). The DOE plans activities to increase codes tee on Science and Technology Subcommittee on Energy and Environ- ment. March 24. and standards work for hybrid components. It has plans NRC (National Research Council). 2008. Review of the 21st Century Truck to explore additional power density needs for heavy-duty Partnership. Washington, D.C.: The National Academies Press. applications, and two of the SuperTruck projects include NRC. 2010. Technologies and Approaches to Reducing the Fuel Consump - hybridization of Class 8 trucks. One recommendation (Rec- tion on Medium- and Heavy-Duty Vehicles. Washington, D.C.: The ommendation 4-7 in NRC, 2008) addressed the structure of National Academies Press. NRC. 2011. Assessment of Technologies for Light-Duty Vehicles. Wash- the partnership between the DOD, the DOT, and the DOE. ington, D.C.: The National Academies Press. Given the separate funding mechanisms of these agencies, Parker Hannifin. 2010. Parker’s Hydraulic Hybrid Technology Helps Truck the DOE acknowledges their central role in fostering cross- Owners Exceed Proposed Federal Fuel Efficiency and Emissions Stan- agency communications. The DOE plans to explore strategic dards. Press Release. November 23, 2010. Available at http://www. alliances with stakeholder organizations. parker.com. Accessed November 30, 2010. TIAX. 2009. Assessment of Fuel Economy Technologies for Medium- and Heavy-Duty Vehicles. Report prepared for the National Academy of Sciences by TIAX, LLC. for the Committee to Assess Fuel Economy Technologies for Medium- and Heavy-Duty Vehicles. July 31. Cuper- tino, Calif.