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2 Alternative Vehicle Technologies: Status, Potential, and Barriers
2 Alternative Vehicle Technologies: Status, Potential, and Barriers
Pages 15-41
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From page 15... ...
Details of the average on-road fleet fuel economy would have to exceed technology assessments are in Appendix F 180 mpg.2 Since that is extremely unlikely, at least with The committee's estimates are not based on detailed evaluations of all the specific technologies that might be used 1 All fuel economy (mpg)
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From page 16... ...
The 2017-2025 light duty fuel economy standards a careful balance between these considerations. were based on analyses that included major improvements Learning also applies to cost.
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From page 17... ...
EPA post-analyzed Ricardo's simulation runs and appor2.2 VEHICLE FUEL ECONOMY AND COST tioned the losses and efficiencies to six categories -- engine ASSESSMENT METHODOLOGY thermal efficiency, friction, pumping losses, transmission efficiency, torque converter losses, and accessory losses. The 2.2.1 Fuel Economy Estimates committee used these results as representative of potential This committee's approach to estimating future vehicle new-vehicle fleet average values in 2025 for the optimistic fuel economy differs from most projections of future ICE case and in 2030 for the midrange case.
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From page 18... ...
-- Battery storage and discharge efficiencies, TECHNOLOGIES -- Electric motor and generator efficiencies, and -- Charger efficiency (BEV and PHEV only) ; Many opportunities exist to reduce fuel consumption · Fuel cell stack efficiency, and CO2 emissions by reducing vehicle loads, as shown in -- lso the FCEV battery loop share of non A Table 2.1.
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From page 19... ...
during the period from the mid 1980s to the mid 2000s A variety of recent studies (see Appendix) have evaluated when fuel prices fell and fuel economy standards were kept the weight reduction potential and cost impact for light duty constant (EPA, 2012)
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Vehicle manufacturers have an incentive to because lighter vehicles are more agile, helping to avoid provide their cars with low rolling resistance tires to maxicrashes in the first place. mize fuel economy during certification.
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From page 21... ...
For low speed driving, e.g., the EPA city driving cycle, about 2.4.1 Conventional Internal Combustion Engine Vehicles one-fourth of the energy delivered by the drivetrain goes to overcoming aerodynamic drag; for high speed driving, one 2.4.1.1 Gasoline Engine Drivetrains half or more of the energy goes to overcoming drag. Under average driving conditions, a 10 percent reduction in drag Engines will improve efficiency in the future by increasresistance will reduce fuel consumption by about 2 percent.
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From page 22... ...
than gasoline engines, which would seem to mandate their There will also be improvements to transmission effi- inclusion in a study of greatly improved fuel economy. The ciency and reductions in torque converter losses.
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From page 23... ...
projections assess the incremental efficiency above that of the stop-start system. More complex systems that allow electric drive and substantial amounts of regenerative braking include paral- TABLE 2.3 Estimated Future Average Fuel Economy and lel hybrid systems with a clutch between the engine and Fuel Consumption the motor, commonly referred to as P2 parallel hybrids Cars Trucks (e.g., Hyundai Sonata hybrid)
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From page 24... ...
While the gains projected by the committee are clearly on body-on-frame light trucks in order to maintain towing ambitious, the rate of improvement for conventional vehicles capacity. Weight and other load reductions were incorpo(including use of stop-start systems and advanced alterna- rated into calculations of the size of the engine, motor, and tors)
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From page 25... ...
requires more expensive infrastructure, and is likely to use Plug-in hybrids are conceptually similar to HEVs. The peak-load electricity with higher cost, lower efficiency, and same set of improvements in fuel economy that will benefit higher GHG emissions.
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From page 26... ...
The series arrangement includes 30 to 100 "virtual" 13 Actual costs for the Leaf and Volt battery packs in 2012 are estimated at about $500/kWh, which reflect lower production volumes. However, note The processing of these materials is subject to considerable cost reduction, that the Leaf battery does not have a liquid cooling system, and the packs as is the cell manufacture.
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From page 27... ...
technology viable, and overall its chance of success is low. A battery recycling effort will be needed when large numbers of battery packs reach the end of their useful lifetimes, 2.5.5 Electric Motors and that will help to control costs.
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From page 28... ...
Overall, motor costs solve the recharging and range problems, it also faces sigare likely to decline from about $2,000 now to less than nificant problems: (1) vehicles and battery packs would have $1,000 in 2050 for a typical electric car.
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From page 29... ...
2.6 HYDROGEN FUEL CELL ELECTRIC VEHICLES 2.5.6.4 Safety The hydrogen FCEV is an all-electric vehicle similar to Battery safety is a critical issue. There are three major a BEV except that the electric power comes from a fuel cell components that characterize the safety of a battery pack: system with on-board hydrogen storage.
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From page 30... ...
fuel economy transients. Significant additional cost reductions will result label values; ICEV fuel economy based on EPA, 2012; FCEV fuel economy if vehicle loads (weight, rolling resistance, and aerodynam- from DOE, 2012a.
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From page 31... ...
FIGURE 2.4 Continuing system simplification contributes to cost reduction. SOURCE: James et al.
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From page 32... ...
Ballard $140 DOE board gaseous fuel storage has been demonstrated worldwide $120 $100 in decades of use in natural gas vehicles. Comparable safety $80 criteria and engineering standards, as applied to ICEVs, $60 HEVs, and CNGVs, have been applied to FCEVs with adap $40 tation of safety provisions for differences between properties $20 of natural gas and hydrogen.
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From page 33... ...
This report assumes that improved technology will gains in fuel cell efficiency are theoretically possible, this reduce costs by 2030 to $33/kW for the midrange and $27/ report assumes only modest improvements from the 2010 kW for the optimistic scenarios. level of 53 percent as shown in Table 2.6.15 Because of the major focus of fuel cell research and The cost of a CFRC hydrogen storage tank varies with development on cost reduction prior to 2030, the committee the pressure and volume capacity.
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From page 34... ...
This allows The midrange estimate for 2050 hydrogen storage cost additional room and flexibility for hydrogen storage tanks. results from continuation of the technology-driven 1 per- Some vehicles have been converted to burn CNG, but until cent per year cost improvement over the 2030-2050 period recently the only dedicated CNG light-duty vehicle sold new in recognition of research into improvements in CRFC in the United States was the Honda Civic Natural Gas vehicle winding patterns and expectation of further improvements (formerly called the GX)
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From page 35... ...
These 2.8.1 Potential Evolution of a Midsize Car Through 2050 design costs are significant for low volume production, but should be almost zero at high-volume. The lower density As an illustration of how a vehicle might evolve with of the fuel means that CNG engines have lower output than increasing fuel economy technology, this section examines a gasoline engines of the same size, though this is mitigated to midsize car, one of the six vehicles the committee analyzed.
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From page 36... ...
While the hybrid system allows elimi TABLE 2.9 Details of the Potential Evolution of a Midsize Car, 2007-2050 2030 2030 2050 2050 Conventional Drivetrain Baseline Midrange Optimistic Midrange Optimistic Engine type Baseline EGR DI turbo EGR DI turbo EGR DI turbo EGR DI turbo Engine power, kW 118 90 84 78 68 Transmission type 6-sp auto 8-sp auto 8-sp auto 8-sp auto 8-sp auto Drivetrain improvements Brake energy recovered through alternator, % -- a 14.1 14.1 14.1 14.1 Reduction in transmission losses, % n/a 26 30 37 43 Transmission efficiency, % 87.6 91 91 92 93 Reduction in torque converter losses, % n/a 69 75 63 88 Torque converter efficiency, % 93.2 98 99 99 99 Reduction in pumping losses, % n/a 74 76 80 83 Reduction in friction losses, % n/a 39 44 53 60 Reduction in accessory losses, % n/a 21 25 30 36 % increase in indicated efficiency n/a 5.6 6.5 10.6 15.6 Indicated efficiency, % 36.3 38.4 38.7 40.2 42 Brake thermal efficiency, % 20.9 29.6 30.3 32.5 34.9 Load changes % reduction in CdA n/a 15 24 29 37 CdA (m2) 7.43 6.31 5.64 5.29 4.68 % reduction in Crr n/a 23 31 37 43 Crr 0.0082 0.0063 0.0057 0.0052 0.0047 % reduction in curb weight n/a 20 25 30 40 Curb weight, lb 3325 2660 2494 2328 1995 Fuel economy, test mpg 32.1 65.6b 74.9 88.5 111.6 NOTE: All conventional drivetrains have stop-start systems and advanced alternators that can capture energy to drive accessories.
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From page 37... ...
real-world fuel consumption. Third, the BEV and FCEV As shown in Table 2.10, the overall hybrid fuel economy numbers are for the vehicle and do not account for the benefit over the corresponding conventional drivetrain vehi- energy needed to produce the electricity or hydrogen.
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From page 38... ...
. Three Incremental Direct Manufacturing Costs over 2010 Baseline the cost estimates assume that high volume production has primary considerations differentiate their prospects for introalready been realized.
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2-11.eps type outlined by their established application in portable commu- 2.10 FINDINGS nication/computer devices, prospects for short-term · Large increases in fuel economy are possible with return on R&D investments are substantial. incremental technology that is known now for both · Infrastructure is discussed in Chapter 3, but it should load reduction and drivetrain improvements.
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From page 40... ...
2006-24306] RIN 2127-AJ61 Average Fuel Economy · If CNGVs can be made competitive (both vehicle Standards for Light Trucks Model Years 2008-2011.
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From page 41... ...
2010a. 2010 Annual Progress Light-Duty Vehicle Greenhouse Gas Emission Standards and Corporate Report for NREL's Controlled Hydrogen Fleet and Infrastructure Analy Average Fuel Economy Standards for Model Years 2017-2025.
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