Review of the Research Program of the Partnership for a New Generation of Vehicles Fifth Report (1999) / Chapter Skim
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2 Development of Vehicle Subsystems
2 Development of Vehicle Subsystems
Pages 16-53
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From page 16... ...
, which is the PNGV power train of choice, uses an energy-storage device to reduce the fluctuations in demand on the primary power plant, thereby permitting a smaller power plant that operates at optimum conditions for increased energy-conversion efficiency and reduced emissions, as well as recovery of a significant fraction of the vehicle's kinetic energy during braking operations. The PNGV is currently sponsoring research on batteries as energy-storage devices.
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From page 17... ...
The 4SDI (four-stroke direct-injection) technical team continues to research four potential engine configurations as power plants for the HEV (see Figure 2-1~.
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From page 18... ...
(1998~. The 4SDI technical team continues to believe that the CIDI engine has the potential for the highest fuel-conversion efficiency.
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From page 19... ...
That is, the development should involve the entire power train system, which includes the engine, drivetrain, fuel, exhaust-gas aftertreatment, and sensors and controls, to take into account the synergistic or antagonistic effects of individual components of the system. According to the 4SDI technical team, the emission targets cannot be met with a reciprocating piston, combustion power plant through combustion control alone, regardless of the power plant under investigation.
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From page 20... ...
E ng~nes Even though the CIDI engine in an HEV configuration is considered the most likely power plant system for meeting the Goal 3 fuel economy target, other configurations of the reciprocating piston engine, including further development of SIDI gasoline engines and PFI SI engines, are being investigated in parallel programs.
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From page 21... ...
. Fuel Formulation The PNGV emission targets represent a technological stretch, particularly for the CIDI engine.
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From page 22... ...
· The DOE initiated a program to promote collaboration with energy companies in the development of fuels capable of achieving the new research target in CIDI engines. · New programs for testing alternative fuels for CIDI engines were started by the USCAR partners.
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From page 23... ...
To date, only bench-scale tests of plasma technology have been done at a space velocity3 of one-half the value expected for CIDI engines based on typical engine configurations. N2 production was detected, but no N2O, HNO3, or HONO by-product species.
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From page 24... ...
Current Program Elements The key performance challenges for achieving the PNGV targets have been identified in the context of 4SDI engines as achieving the very low required levels of NOX and particulate matter emissions while maintaining performance. The goals of the technical program are to develop enabling technologies in the areas of fuels, combustion systems, after-treatment, and controls and sensors.
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From page 25... ...
In 1999, testing will be done with a smaller CIDI engine that is more representative of the power plant for the PNGV concept vehicles. Engine testing of the plasma-assisted catalyst is scheduled to begin in 1999, which would enable the technical team to evaluate the effect of the plasma on the particulates in the exhaust.
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From page 26... ...
As regulatory requirements for emissions (NOx and particulate matter) become tighter, unless the fuel is reformulated, it is not likely that the CIDI engine, or any other 4SDI power plant, will be able to meet the PNGV targets for fuel economy and emissions.
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From page 27... ...
At this time, the 4SDI technical team is attempting to identify critical challenges and has not addressed this issue. If this situation does arise, all of the PNGV partners should be actively involved in the prioritization, which will affect the power plant for the concept vehicle and the direction of future research.
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From page 28... ...
Further catalyst development is needed to lower the nitrous oxide production because of its high global-warming potential.4 Particulate matter emissions can be reduced with exhaust-treatment technology through a combination of an oxidation catalyst and particulate trap. This approach has received less attention recently because engine controls plus an oxidation catalyst and some sulfur reduction in diesel fuel have been highly effective in reducing the particulate emissions of CIDI engines, and additional improvements are possible.
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From page 29... ...
The 4SDI technical team should develop projections of the performance of compression-ignition direct-injection and gasoline directinjection power-train systems, especially comparisons of the estimated emissions and fuel economy for each system. These projections would be a first step toward the quantification of trade-offs between emissions and fuel economy based on current and emerging state-of-the-art technologies.
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From page 30... ...
Other reasons for a hybrid vehicle are for fast power response (also related to transient response of the fuel processor) and to provide a reservoir for recovering part of the braking energy through regeneration (which is not related to the characteristics of a fuel processor)
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From page 31... ...
The following activities have been completed: In 1997, AD Little (ADL) demonstrated a 1-kW gasoline fuel processor with a PEM stack.
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· In 1999, IFC and PlugPower plan to demonstrate a 50-kW fuel-flexible fuel processor with a PEM stack.
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From page 33... ...
LANL has designed and tested a 50-kW modular preferential-oxidation (PrOx) fuel processor that, through three stages, reduced CO from 8,000 ppm to 30 ppm.
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From page 34... ...
Ballard has also entered into a joint venture with GEC Alsthom to supply fuel cells for stationary applications in Europe and Canada. Ballard continues to supply stacks for the majority of both U.S.
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PNGV should re-examine its fuels selection for fuel cells, taking into account the anticipated technical difficulties and cost implications of using gasoline as the onboard fuel.
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From page 36... ...
ELECTROCHEMICAL ENERGY STORAGE Introduction To reach the fuel-efficiency goals of up to three times the value prevailing for midsized passenger vehicles in 1993, an energy-storage subsystem will be necessary to provide load leveling for the primary power plant and to store energy recovered through regenerative braking. Load leveling in an internal-combustion engine can reduce the size and mass of the engine, improve the average thermalenergy efficiency, and permit better emissions control.
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From page 37... ...
30kW 4okwa Available energy 0.3kWh 3kWh Energy efficiencyb ( 90% ( 95% 93% 77% Cycle life at ASOC = 1.5% 200k cycles 200k cycles at ASOC = 3% 120k cycles 120k cycles Calendar life 10yrs 10yrs 2.5yrsC 5yrs Maximum mass 40kg 65kg Maximum volume 32L 40L Production costs @ 100k/yr $300 $500 Operating temperature range -40° to 52°C -40° to 52°C Available specific energy 12Wh/kg 83Wh/kg 38Wh/kg 12Wh/kg Available energy density 24Wh/L 188Wh/L 82Wh/L 36Wh/L Specific power (18 s discharge) 960W/kg 1,800W/kg 960W/kg 290W/kg Cost per rated energy $833/kWh $134/kWh $450/kWh $1400/kWh aRevised downward from 70 kW.
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From page 38... ...
Energy and power goals thus appear to be attainable, but in all cases achievement of the goals for cycle life and calendar life is questionable for lithium-ion technology. VARTA, the sole developer for nickel metal hydride batteries, has achieved 400 W/kg and 30 Whlkg in 10-Ah cells.
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From page 39... ...
Without these trade-offs, a fuel-cell powered, series hybrid vehicle may have to be precluded. If the interactions among partial hybridization and the size, fuel efficiency, transient response, and emissions of the primary power plant are well understood, the disparity between targets for power-assist and dual-mode hybrid vehicles could be eliminated.
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From page 40... ...
The committee is not calling for a drastic reorientation of the program because the development of high-risk systems, like lithium-ion and nickel metal hydride batteries, is appropriate for the PNGV, and more conventional batteries provide suitable fallback positions. Failure to meet goals may reflect the inappropriateness of the goals rather than the impending failure of the entire project.
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From page 41... ...
FLYWHEELS A flywheel energy-storage subsystem on board an automobile has been defined as a relatively low-energy device (i.e., with 30 kW of power and 300 Wh of energy storage) suitable for application to fast-response power plants.
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From page 42... ...
In either case, success depends on the development of efficient, economic actuators, motors, and power electronic converters. Status and Progress The electrical and electronic systems technical team (EE technical team)
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From page 43... ...
The EE technical team has verified the presently achievable cost of $15/kW (peak) for power electronics through modeling done separately by each USCAR partner.
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From page 44... ...
Functionality of the power electronics and electrical system is not an issue in these vehicles. Although the development of electrical accessories was not explicitly addressed during this review, the committee notes that several of the development programs under the BE technical team' s umbrella are focused on accessories.
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From page 45... ...
Materials Road Map The PNGV materials team has developed a road map that identifies lightweight material alternatives for the major subsystems of the vehicle. Alternative materials are prioritized based on their weight-saving potential and feasibility to meet the PNGV time requirements.
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From page 46... ...
The committee has suggested that the materials technical team use the U.S. Automotive Materials Partnership (USAMP)
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From page 47... ...
Examples of candidate subsystems are: wheels, brakes, suspension components, and power trains. If a vehicle is designed from the ground up, secondary weight reductions can be as much as 0.5 lbs for every 1.0 lb of primary weight reduction.
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From page 48... ...
and average weight savings of 47 percent, the cost penalty of an aluminum BIW is estimated at $400, including incremental manufacturing costs. Current PNGV programs involving direct casting of thin aluminum sheet, which avoids expensive hot-rolling processes, have the potential to reduce the cost of aluminum sheet to $1.00/lb (Table 2-5)
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From page 49... ...
The PNGV BIW weighed 90 kg on a baseline BIW that weighed 285 kg in steel, or a 68.5 percent weight savings. This is significantly better than the 59 percent forecast by the PNGV materials team last year and close to what might be expected from a structural analysis assuming adequate material properties.
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From page 50... ...
Also, work continues on lightweight glazing materials (e.g., thin glass and polymers) , which offer a potential weight savings of 50 lbs.
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From page 51... ...
are directed toward reducing the weight of the power train and chassis, but the committee was apprised that progress has been made in only a few projects, primarily because many of the projects in this category are new. The materials technical team has identified a process for tracking progress in all road-map projects.
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From page 52... ...
The added costs are associated with differences in spring-back characteristics, die maintenance, joining technologies, and recycling costs. During the past year, the fabrication of a hybrid material, CFRP BIW, from thin sheet and sandwich materials, as well as some aluminum extrusions, demonstrated an impressive 68.5 percent weight savings over a steel baseline vehicle.
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From page 53... ...
Recommendation. The PNGV materials technical team should endeavor to decrease the gap between the PNGV targets for weight savings and the actual identified weight savings for the power-train and chassis subsystems.
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