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 133
OCR for page 134
OCR for page 135
OCR for page 136
OCR for page 137
OCR for page 138
OCR for page 139
OCR for page 140
OCR for page 141
OCR for page 142
OCR for page 143
OCR for page 156
OCR for page 157
OCR for page 158
OCR for page 159
OCR for page 160
OCR for page 161
OCR for page 162
OCR for page 163
OCR for page 164
OCR for page 165
OCR for page 166
Representative terms from entire chapter:
fuel consumption
F
Letter Report:
Technology and Economic Analysis in the
Prepublication Version of the Report
Effectiveness an`/ impact of
Corporate Average Fuel Economy (CA FEJ Stan~lar~ls
Hi' C>240 t4£.5 ~~5~20f'55 tiff2,~f
~ `. ~ . 5 all . I) ~ ,, i, ~ ., . ~ ~ ' ~ y ~ 2 ~ x):, . ~ .) 5; I'm
t`~5~c494~{,,f'~;',55i ';C'~V 5''5'',~)7~t=~^2l.~' -I'm 'it
|~-'t5~35~-, <3'~\,461~35~:Ji;C'.,',...
2~'C --45t, j f'532' 86 ~;~53 -ala t 5~ . ~ ~.~ ~~ ~ t
f'i''~e l.~ j~iS'`~\ \\r~ ~~t')~0
^~) ~ `) 2 $tft~f~
0ft']~] ~~ ll<~0 5~\ \~5'tt~0
Con ~ TV
~~ ~ ~ ,)54~'l~'0t 0t i~]
4~t S\\r Room532~)
Of 06~(')
]af'lus<~S I,4~t,)~2
Low Dr. ~~£gi~o
I, 3~ p}~62~6 t~ 60~.],~t t~.3 lift t0~ t~ )~ Lt ~~5~f~f~25 I'll ~540~7
aid to Is t~0 p0~]f.~543] ~t iUCl ~2~0m\/ g£~5~, }~ t~0 ~~8l ~54280~ 0~< {l
({'~) 5t^~ ~i'~/'~62
134
EFFECTIVENESS AND IMPACT OF CORPORATE AVERAGE FUEL ECONOMY (CAFE) STANDARDS
or i4' 2002
~4
~40
Research COunCti.~! A.c
~ A ~ ~ ~ my ~ 8~ t\{ ~ 6~] ~ ~ ~ ~ ~8
202~:42
.~ ~ ~
ot :.
APPENDIX F
Technology and Economic Analysis in the Prepublication Version of the
Report Effectiveness and Impact of Corporate Average Fuel
Economy (CAFE) Standards
This letter report summarizes the reexamination of several technology issues originally
presented in the prepublication report by the Committee on the Effectiveness and Impact of
Corporate Average Fuel Economy (CAFE) Standards. It first explains WhY the reexamination
. . . . .. ~ . · . ..
— ~— ~
was undertaken and the process for doing so. it then evaluates the methodology used in Chapter
3 of the prepublication version of the report for estimating the benefits of improved technolo~v.
corrects several minor errors, and explains the results. In doing so, it stresses the committee s
desire that readers focus on averages! estimates for cumulative gains and costs instead of the
upper and lower bounds, which reflect the increasing uncertainty of costs and benefits as fuel
efficiency is increased. It also updates and explains the economic analysis presented in Chapter 4
of the prepublication version.
~ lo,,
.. . . ~ ... .
REASONS FOR THIS LETTER REPORT
At the request of the U.S. Congress, the National Research Council (NBC) released a
prepublication version of its report Effectiveness ant! Impact of Corporate Average Fuel
Economy (CAFE) Standards in July 2001. The committee prepared the report in less than 6
months because Congress expected to aciciress CAFE standards in 200 1 ant} had requested
guidance on technical feasibility. During the study, President George W. Bush announced that
this report would be an important factor in his energy policy, prepared uncler the direction of
Vice President Richard Cheney.
During this initial 6-month period, the committee held a series of public meetings at
which representatives of automobile manufacturers, governmental agencies, and a variety of
nongovernmental organizations provided information on the issues addressed in the report. The
committee also visited! manufacturers and major suppliers, reviewed thousands of pages of
presentation and other background material, and retained consultants to provide detailed
analyses.
Following the release of the prepublication report, the automotive industry challenged
some of the estimates for improved fuel economy. Representatives of the Alliance of Automobile
Manufacturers (AAM), General Motors, and DaimierChrysTer told the NRC in August 2001 that,
in their opinion, portions of the technical analysis in Chapter 3 were fundamentally flawed! ant!
that some of the estimates for fuel economy improvements violated the principle of conservation
of energy. In particular, the industry claimed that the method used to estimate incremental
improvements in fuel consumption through stepwise application of technologies did not consider
system-level effects and that "double-counting" of potential reductions in energy losses had
occurred, especially in upper bound estimations which resulted in the violation of the first law of
thermodynamics (conservation of energy.
t The largest energy loss is due to inefficiency of the engine. The maximum efficiency of a typical current
spark-ignition engine is about 35 percent. The remainder of the energy in the fuel is transferred to the atmosphere
as thermal energy in the exhaust or through the cooling system. Some of the technologies discussed here raise
efficiency, but in general it is difficult to significantly reduce these losses. Other technologies indirectly accomplish
135
136
EFFECTIVENESS AND IMPACT OF CORPORATE AVERAGE FUEL ECONOMY (CAFE) STANDARDS
In response to these concerns, especially in light of the potential impact of the report's
findings and recommendations on national energy policy, the committee held a public meeting
on October 5, 2001. Industry representatives and several analysts with other perspectives
presented their questions and concerns about the report.2 The presentations are available in the
NBC's public access file.
In addition to the allegation of violating the principle of conservation of energy, industry
raised other issues including the following:
1. Some technologies are already in widespread use, so the improvement from
implementing them for a particular class of vehicle is minimal.
2. Improvements from some technologies are overstated.
3. Baseline fuel economy levels do not match Environmental Protection Agency (EPA)
data.
4. Some data supplied to the committee may have been misinterpreted as based on fuel
consumption rather than fuel economy, leading to an overstatement of benefits.
Because of these errors, the break-even analysis in Chapter 4 overestimates the
benefits of raising fuel economy standards.
Feng An presented some of the results from a recent report by the American Council for
an Energy Efficient Economy (ACEEE) and commented on the automotive industry's
presentation. He pointed out that the ACEEE analysis, which was based on detailed energy
balance simulation, predicted results similar to those in the committee's report when weight
reduction was excluded. He also noted that industry's treatment of engine idle-off was inaccurate
and that analysis of energy losses was a matter of engineering judgment as well as exact
mathematics. He concluded that some double-counting of benefits may have occurred in the
committee's most optimistic estimates. However, he argued that two other factors counter this
problem. First, other technologies could reasonably have been included by the committee,
especially weight reduction and hybrid-electric vehicles. Second, combining technologies can
produce positive synergies,3 which may not have been considered.
David Friedman stated, among other things, that the committee had clearly eliminated
most double-counting, and, insofar as some may have occurred, the committee could have
considered additional technologies to achieve the same or greater levels of fifed economy. He
this goal; e.g., friction reduction results in less heat transfer from the radiator. Many of the engine technologies
discussed here typically are applied to reduce pumping losses (the energy required to move the air for combustion
through the engine), a smaller loss but one easier to reduce. As these technologies are added, pumping losses
decline, reducing the potential for the next technology. If these diminishing returns are not considered, the analysis
may overpredict the reduction in pumping losses, resulting in double-counting. However, many of these
technologies have secondary benefits as well, which also must also be considered. The term "system-level effects"
refers to these interactions.
2Formal presentations were made by Greg Dana of the Alliance of Automobile Manufacturers; Feng An, a
consultant working with the Energy Foundation and the American Council for an Energy Efficient Economy; and
David Friedman of the Union of Concerned Scientists. Accompanying Mr. Dana were Aaron Sullivan of General
Motors (who made an additional informal presentation), Tom Asmus of DaimlerChrysler, Tom Kenny of Ford, and
Wolfgang Groth of Volkswagen. In addition, Barry McNutt of the Department of Energy made an informal
presentation.
3System-level effects can be positive as well as negative. The term "synergies" is used when the benefit is
greater than the sum of the individual contributions.
APPENDIX F
believed that with those technologies, even the most optimistic upper bound could be achieved.
He noted that losses due to aerodynamic drag, rolling resistance, and inertia can easily be
reduced more than the committee had allowed, and probably at lower cost than some of the
technologies that are on the committee's list. In abolition, hybrid electric vehicles (HEY) may
become competitive faster than the committee had assumed, and positive synergies were not
always included in its analysis.
The committee, in particular the Technology Subgroup,4 examined the concerns
expressed at the October 5 public meeting, reviewed acIditional materials submitted by interested
parties, evaluated the potential for fundamental errors in its original analysis, and wrote this
report to present its findings. This effort has been limited to the technology methodology
an.' .. . -
presented in Chapter 3 of the prepublication version ant! the potential impact any revisions would
have on the economic analysis in Chapter 4.
The review uncovered several minor computational or data entry errors in the original
analysis. These are identified here and corrected in the final CAFE report, scheduled for
publication in early 2002. In addition, the methodology used for estimating the fuel efficiency
improvements is explained in greater detail, as is the increasing uncertainty in upper and lower
) sounds in the prepublication version of the report. These bounds have been eliminated in the
final report and in this letter report in order to help focus the reader on the average estimations.
FINDINGS
Based on its review of the information provicled to it subsequent to the July 2001 release
of the prepublication version of the CAFE report, in combination with additional investigations
conducted by the Technology Subgroup, the committee finds as follows:
. The fundamental findings ant! recommendations presented in Chapter 6 of the CAFE
report are essentially unchanged. The committee still finds that "technologies exist
that, if applied to passenger cars and light-duty trucks, would significantly reduce fuel
consumption within ~ 5 years" and that "assessment of currently offered product
technologies suggests that light-duty trucks, including SWs, pickups, and minivans,
offer the greatest potential to reduce fuel consumption, on a total-galilons-savec}
basis." The only changes to the finclings ant! recommendations presented in the
prepublication version are the references to the analyses presented in Chapters 3 and
4, which have been modified as discussed in the section "Technical Discussion,"
below, and Attachments A through E.
Baseline fuel consumption averages have been reviser! to reflect the latest results
published by EPA for mode} year 1999. The technology matrixes have been modified
to eliminate unlikely combinations that were erroneously camed forward in the
spreadsheets (see Tables 3-l to 3-3 in Attachment A). Calculations of incremental
reflections in fuel consumption for certain vehicle ciassesS also have been corrected.
4John Johnson, Gary Rogers, Phillip Myers, and David Greene.
Midsize and large cars should have used camless valve actuation instead of intake valve throttling in path
3. The benefits of variable valve timing should have been 2-3 percent (instead of 1-2 percent) and variable timing
and lift should have been at 1-2 percent (instead of 3-8 percent).
137
138
EFFECTIVENESS AND IMPACT OF CORPORATE AVERAGE FUEL ECONOMY (CAFE) STANDARDS
These changes had a mixed effect on fuel economy estimates, but the net result is to
slightly lower the averages. In addition, the upper and lower bounds in Table 3-4 and
Figures 3-4 to 3-13 of the prepublication version have been removed (see Attachment
A). The greatly increased uncertainty as technologies were added caused considerable
confusion, and the committee decided to simplify the presentation. The economic
analysis has been modified to reflect these changes and several other minor
modifications, as discussed in the section "Analysis of Cost-Efficient Fuel Economy
Levels," below, and shown in Attachment B. These changes, which are incorporated
into the final CAFE report, had no significant impact on the overall findings and
recommendations of the report because the average estimates changed so slightly.
The committee notes that its analysis of the incremental benefits of employing
additional fuel-efficient technologies was, of necessity, based largely on engineering
judgment. A detailed energy balance simulation of all the technologies in all the
vehicle classes could potentially improve the accuracy of the analysis, but that task
was well beyond the resources of the committee. The prepublication version of the
report states, "Within the time constraints of this study, the committee used its
expertise and engineering judgment, supplemented by the sources of information
identified above, to derive its own estimates of the potential for fuel economy
improvement . . . ." The report also notes that "the committee has applied its
engineering judgment in reducing the otherwise nearly infinite variations in vehicle
designs and technologies that would be available, to some characteristic examples."
Moreover, as confirmed during testimony presented by AAM representatives, the
committee did not have sufficient proprietary technical data to conduct highly
detailed simulations. Additional explanation of this estimation process is presented in
the "Technical Discussion" section, below.
4. The committee acknowledges that, although it was conservative in its estimates of
potential gains attributable to individual technologies (in an attempt to account for
potential double-counting), some overestimation of aggregated benefits, compared to
aggressive development targets, may have occurred in paths 2 and 3 in the
prepublication version. Nevertheless, the committee finds that the principle of
conservation of energy was not violated. Furthermore, the committee may have
underestimated some potential improvements and given insufficient consideration to
system-level synergies.
The committee conducted a more detailed simulation to determine whether significant
overestimations of potential benefits may have inadvertently occurred. Only one case
(midsize SWs) was considered in the time available, but this case provides a general
confirmation of the methodology used in the CAFE report. This analysis (cletailed in
the technical discussion and in Attachment C), shows that the most optimistic upper-
bound estimate in the prepublication version exceeded aggressive development
targets by less than 1 0 percent. The same analysis suggests that if pumping losses
were reduced to extremely low levels (due to unthrottled operation) and Fiction was
reduced bv 30 to 40 percent (theoretically possible but not currently feasible for
APPENDIX F
production engines), fuel consumption reductions would equal the most optimistic
upper-bound estimate for midsize SUVs in the prepublication version.
Therefore the committee finds that its analysis did not violate any laws of energy
conservation. The committee acknowledges that the uncertainty associated with any
upper boundary increases significantly as additional technologies are considered.
Accordingly it does not propose them as development targets.
All estimates (even those involving sophisticated modeling) of the costs and benefits
of new technologies are uncertain. As technologies are added, the overall uncertainty
increases. The committee included a wide range of costs and benefits for each
technology to account for such uncertainties. However, based upon the feedback
received since the release of the prepublication version, the committee believes that
the increasing level of uncertainty associated with moving up each of the three paths
was not sufficiently explained in Chapter 3. Additional technical discussion and
clarification are therefore included below. Furthermore, the committee finds that its
methoclology for determining the collective uncertainty as technologies are added has
produces! wide upper- ant! Tower-bounc! estimates that have contributed to confusion
and misinterpretation of the analysis. Chapter 4 uses a statistical technique to narrow
the bouncis (using the values for each technology in Chapter 3 as input), as seen in
Figures 4-5 and 4-6 in Attachment B. This technique maintains an approximately
constant confidence bound over the range of fuel economy. Therefore, the upper and
lower bounds for improved fuel consumption and associated costs are dropped from
Table 3-4 and Figures 3-4 to 3-13 (see Attachment A), and only the now slightly
lower averages are retained in order to focus attention on the most probable and
useful results. However, the reader is cautioned that even the averages are only
estimates, not exact predictions.
CONCLUSIONS
Based on the additional information provided to the committee subsequent to the July
2001 release of the prepublication version of the CAFE report, including testimony provided at
the October 5, 2001, meeting, the committee concludes as follows:
I. The committee reaffirms its approach and general results: Significant gains in fuel
economy are possible with the application of new technology at corresponding
increases in vehicle price. Although the committee believes that its average estimates,
as presented here, provide a reasonable approximation of the fuel economy levels
attainable, it endorses its statement in the prepublication version namely, that
changes to CAFE standards should not be based solely on this analysis. Finding 5 of
the CAFE report states: "Three potential development paths are chosen as examples
of possible product improvement approaches, which illustrate the trade-offs auto
manufacturers may consider in future efforts to improve fuel efficiency." The finding
also notes that "economic, regulatory, safety, and consumer-preference-related issues
will influence the extent to which these technologies will be applied in the United
States."
]39
140
EFFECTIVENESS AND IMPACT OF CORPORATE AVERAGE FUEL ECONOMY (CAFE) STANDARDS
2. The fuel economy estimates include uncertainties that necessarily grow with the
increasing complexity of vehicle systems as fuel economy is improved. Thus for
regulatory purposes, these estimates should be augmented with additional analysis of
the potential for improvements in fuel economy and, especially, their economic
consequences. The development approaches that manufacturers may actually pursue
over the next ~ 5 years will (1epend on improvements made in current systems, price
competitiveness of production-intent technologies, potential technological
breakthroughs, advancements in diesel emission-control technologies, and the quest
for cost reduction in hybrid technology.
Path 3 includes emerging technologies that are not fully developed and that are, by
definition, less certain. The committee also recognizes that this path includes
technologies that likely have not been tested together as a system. The upper and
lower bounds of the paths are even more uncertain than the average. Therefore in
formulating its conclusions, the committee used the path averages.
Full analysis of systems effects, which might be better definer! by more rigorous
in(lividual vehicle simulations, could suggest fuel economy improvements that are
greater or less than the average estimates made by the committee. More accurate
estimates would require detailed analyses of manufacturer-proprietary technical
information for individual vehicle models, engines, transmissions, calibration
strategies, emissions control strategies, and other factors information to which the
committee has no access. Even if such information were provided, evaluating all
possible scenarios would require a prohibitive number of simulations for the
committee to pursue.
3. Based on input provided subsequent to the July 200 ~ release of the prepublication
version, the committee concludes that additional technologies, beyond those
iclentifiec} in the report, may also become available within the ~ 0-] 5 year horizon. The
committee may have underestimated the vehicle-based (e.g., aerodynamics, rolling
resistance, weight reduction) benefits that may be expected within ~ 5 years.
Prototype vehicles are now being designed and tested that achieve significantly
higher fuel economy (FE) than the levels considered by the committee (see the
section "Future Potential," in Attachment D). While the committee has not analyzed
all of these concepts (they still must surmount a series of banners, including cost,
emissions compliance, and consumer acceptance issues), it notes that they illustrate
the technical potential for greater fuel economy.
4. At the August 2001 meeting, industry representatives stated that the methodology
used by the committee violated the principle of conservation of energy.6 However, at
6The industry representatives separated the technologies according to how, in their judgment, they might
reduce energy losses. They expected most technologies to contribute to reducing pumping and engine friction losses.
When they added all the improvements from those technologies, the total exceeded some relative value assumed to
represent the combined EPA city/highway cycle for a single vehicle example. This was the basis for the claim that
APPENDIX F
the October 2001 meeting, no detailed energy balance formulations or indepenclent
analyses were presented to support this claim. Rather, industry representatives
presented their judgment-based contributions of the different technologies considered
by the committee to reduce energy losses. The representatives then summed these
contributions, suggesting that the committee's methodology overestimates the
potential improvement and thereby violates the conservation of energy principle.
The committee has several points of contention with industry's formulation of the
energy balance issue: for example, the allocation of the benefits of an integrated
starter-generator (with idle-ofi~ to pumping, friction, ant} transmission. While turning
off the engine when power is not needled (i.e., during idle or braking) does not raise
the efficiency of the engine itself, it does lower the energy required for the EPA test
cycles used to measure fuel efficiency. Thus idle-off effectively results in an increase
in overall fuel economy, which can be realized without violating the conservation of
energy. This effect varies the relationship between engine losses and fuel
consumption that has historically been considered when estimating fuel economy.
Regenerative braking, although not considered in the three hypothetical paths, is
another example of fuel economy improvement being essentially independent of
· ^, ~
engine ettlclency.
In addition, assumptions as to primary and secondary benefits must consider varying
trade-offs as many new technologies are aggregated. The committee therefore
concludes that differences in engineering judgment are likely to produce significantly
different approximations when projecting some ~ 5 years into the future.
The committee agrees that achieving the most optimistic (upper bound) results of path
3 in the prepublication version of the report with the technologies iclentified there
wouIc} require overcoming great uncertainty and technical risk. The committee did not
regard the upper bound as a viable production-intent projection. It is a bound, by
definition, as is the lower bound, and plausible projections lie somewhere in between.
Furthermore, consumer acceptance and real-worId characteristics will certainly cause
actual fuel economy gains to be less than the technically feasible levels presented in
this stiffly.
5. The committee reaffirms its position in Fincling 6 of the CAFE report: "The
committee cannot emphasize strongly enough that the cost-efficient fuel economy
levels identified in Chapter 4 are not recommended CAFE goals. Rather, they are
reflections of technological possibilities, economic realities, and assumptions about
parameters values and consumer behavior." The fuel economy estimates in Chapters
3 and 4 describe the trade-offs between fuel economy improvement and increased
vehicle price. They do not incorporate the value of reducing U.S. oil consumption or
greenhouse gas emissions. Nor are they based on particular views of the
the NRC analysis violates conservation of energy. The presentation, but not the specific charge, was repeated at the
October meeting, yet the detailed propriety data behind the relative assumptions were not offered.
141
142
EFFECTIVENESS AND IMPACT OF CORPORATE AVERAGE FUEL ECONOMY (CAFE) STANDARDS
appropriateness of government involvement. The committee provides some
discussion of these issues, but the value judgments must be left to policy makers.
TECHNICAL DISCUSSION
Methodological Issues
The state of the art in overall powertrain simulation, including gas exchange, combustion,
heat loss, exhaust energy, and inclicated thermodynamic efficiency, has advanced with the
development of computing capacity, computational fluid dynamics, and mechanical system
simulation. Automotive manufacturers, subsystem suppliers, private and governmental research
institutions, and universities around the world are investing vast resources to improve the
accuracy of such predictive tools.
Expansion of the simulation to include the transmission, drivetrain, tires and wheels,
vehicle aerodynamics, rolling resistance, frictional losses, accessory loads, and the influence of
control system response, calibration strategies, and hundreds of other parameters creates models
of sufficient size to tax even high-power computers. Morever, such sophisticated models still
require experimental verification and calibration and are best used to quantify incremental
improvements on individual vehicle models. They also require the input of proprietary data.
The committee's charge was to estimate the potential for fuel economy improvements,
not to define new regulatory standards. Hence it clesired only a general understanding of the
potential for fuel economy gain for different types of vehicles and what the relative costs might
be. In aciclition, the committee wished to determine Which technologies are currently being
applier! in markets where the high price of fuel provides an economic incentive for the
introduction of new technology for reduced fuel consumption.
Although the committee is familiar with the state-of-the-art analytical methods identified
above, it slid not have the resources, time, or access to proprietary data necessary to employ such
methods. Therefore it used a simpler methodology to provide approximate results. The
committee identified candidate technologies, as explained in Chapter 3 of the prepublication
version of the report, that could be considered for application in various types of vehicles. It then
estimated ranges of possible improvements in fuel consumption and costs associated with these
technologies. Finally, it assembles! packages of technologies, deemed revelant to different
vehicle classes, and estimated the total impact on fuel economy and costs. This approach allowed
the committee to estimate potential changes in a wide variety of vehicle classes within the
boundary conditions of the study. The committee notes that similar methods were used in the
~ 992 NRC analysis of automotive fuel economy potential (NRC, 1 992) and by many studies in
the published literature over the past 25 years (see, e.g., Greene and DeCicco, 2000, for a
review).
Analytical Issues
Technical input to the study included a review of technical publications, a review of
automotive manufacturer announcements of new technology introductions and reported fuel
consumption (economy) benefits, and information acquired directly from automotive
manufacturers and suppliers in the United States and abroad. The committee evaluated vehicle
APPENDIX F
features (engine size, number of cylinders, state of technology) and published performance and
fuel economy data. It assessed engine, transmission, and vehicle-related energy consumption,
system losses, and potential improvements in thermal or mechanical efficiency. Finally, the
committee applied engineering judgment to reduce an exceedingly complex and seemingly infinite
number of possible technology combinations and their relative performance, fuel consumption,
dnvability, production costs, and emissions compliance trade-offs into a more manageable,
though approximate, analysis.
Most of the technologies considered in the committee's analysis either are in, or will soon
enter, production in the United States, Japan, or Europe. Promising emerging technologies,
which are not completely developed but are sufficiently well understood, were also included.
Background information concerning these technologies is given in Chanter 3 of the CAFE report.
The potential choice of technologies differs by vehicle class and intended use. In addition, the
ease of implementation into product plans and consumer-based preferences will influence
whether a technology enters production at all.
The analysis was complicated by the need to infer potential fuel consumption benefits from
published data in which experimental results were based on European (NEDC) or Japanese (10/!
mode) test cycles. Furthermore, differences in exhaust emission regulations, especially between
European and U.S. Tier TI or California standards, can have a great effect on the potential
application of several technologies.7
The potential of each technology to improve fuel economy, and the costs of implementing
the technology, were determined Mom the sources listed above. Both fuel economy (FE) benefits
and costs are expressed in terms of a range, with low and high values, because of the uncertainty
involved.8 The benefit is expressed as a percent reduction of fuel consumption (FC; gallons/IOO
miles).
The fuel consumption ranges were adjusted in an attempt to account for potential double-
counting of benefits. Attachment E shows how FC improvements were modified to avoid
double-counting. It also shows that most of the technologies considered have primary and
secondary benefits related to the reduction of different types of losses or improvements in
thermal efficiency. In general, this strategy results in predicted improvements for individual
technologies that are lower than the values commonly found in the literature.
In addition, subsequent to the release of the prepublication version, the committee
simulated one case, the midsize SUV, in order to evaluate potential inaccuracies in its simplified
methodology. This sample simulation is presented in Attachment C.
To assist in evaluating near-term potential (within ~ O years) versus long-range predictions
(l O- ~ 5 years or beyond), the committee considered three technology paths with three different
levels of optimism regarding technology implementation. The technologies grouped within these
paths were chosen based on current production availability (in the United States, Europe, or
Japan), general compatibility with the dominant vehicle attributes (engine size/power, transmission
This is especially true in the case of lean combustion concepts (direct-injection diesel and gasoline), which
are unlikely to penetrate U.S. markets rapidly due to production cost and emissions compliance issues, even though
they are quickly approaching 50 percent of the new vehicle sales in Europe. The committee examined these
technologies but did not include them in any of the paths because of high uncertainty concerning exhaust emissions
compliance and production cost. Nevertheless, it is quite possible that one or more will be successful. In such a case,
fuel economy levels higher than any of those estimated by the committee could become feasible.
~ Note that the economic analysis in Chapter 4, including that in the prepublication version, heavily weights
the average but statistically considers the uncertainty represented by the high and low values.
143
156
EFFECTIVENESS AND IMPACT OF CORPORATE AVERAGE FUEL ECONOMY (CAFE) STANDARDS
l Multivalve, Overhead Camshaft (2V vs. 4V) FC Improvement
From Base From Ref.
Technology Improvement from 2 valve engine into a multiintake valve engine (including
Description total of 3, 4, and 5 valves per cylinder)
Primary Benefits Lower pumping losses: larger gas exchange flow area
Less friction: higher mechanic efficiency due to higher engine IMEP
Secondary Less pumping losses: engine down size with higher power density
Benefits Higher thermal efficiency: higher compression ratio due to less knocking
tendency and faster combustion process with central spark plug position
FC Improvement Base: 2V baseline engine Reference: 2V baseline en-tine 2 ~ 5% 2 ~ 5%
. .
Example of Advanced engines from Ford, GM, and DC
Application
| Reference | Volkswagen:R.Szengel,H.Endres | | 11%FCin
6. Aachener Kolloquium (1997) MVEG
Conclusion: A 1.4L-14-4V engine improves the fuel consumption by 11%
(MVEG) in comparison to a 1.6L-14-2V engine
, . ~
_ -ord: D. Graham, S. Gerlach, J. Meurer. SAE-Paper 962234 4 5% FC
Conclusion: new valve train design (from OHV to SOHC) with 2 valves per (OHV, 2V to
cylinder plus additional changes (higher CR, less valve train moving mass) SOHC, 2V)
result in a 28% increase in power, 11% increase in torque and 4.5% +28% power
I reduction in fuel consumption (11.2 to 10.7 UlOOkm, M-H) for a 4.0L-V6-2V | | +11% torque
engine.
Sloan Automotive Laboratory / MIT: Dale Chon, John Heywood
SAE-Paper 2000-01-0565
Conclusion: The changing preference from 2-valve to 4-valve per-cylinder is
a major factor of current engine power and efficiency improvement; the
emergence of variable valve timing engines suggests a possible new trend
will emerge.
APPENDIX F
157
l Variable Valve Timing (VVT) | FC Improvement
From Base From Ref.
| Technology ~ Variable valve timing in the limited range through cam phase control ~ l
Description
| Primary Benefits | Less pumping losses i: later IVC to reduce intake throttle restriction for the | I
same load
Secondary Less pumping losses: down size due to better torque compatibility at high
Benefits and low engine speed for the same vehicle performance
FC Improvement Base: 2V baseline engine; Reference: 4V OHC en-tine 4 ~ 8 % 2 ~ 3 %
.
Example of Toyota VVT-i; BMW Vanes
Application
Reference Ford: R.A. Stein, K.M. Galietti, T.G. Leone 2.8 ~ 3.2%
SAE-Paper 950975 V8, 2V engine
Conclusion: for a 4.6L-V8-2V engine in a 4,000 lb vehicle benefit in M-H fuel
consumption of 3.2% with unconstrained cam retard and 2.8% (M-H) with
constrained cam retard (10% EGR)
Ford: T.G. Leone, E.J. Christenson, R.A. Stein 0.5-2.0%
SAE-Paper 960584 14, 4V engine
Conclusion: for a 2.0L-14-4V engine in a 3,125 lb vehicle benefit in M-H fuel
consumption of 0.5-2.0% (10-15% EGR)
Toyota: Y. Moriya, A. Watanabe, H Uda, H. Kawamura, M. Yoshioka, M. 6%
Adachi. SAE-Paper 960579 Japanese
Conclusion: for a 3.0L-16-4V engine the VVT-i technology (phasing of intake mode
valves) improved the fuel consumption by 6% on the 10-15 official Japanese 16, 4V engine
mode.
Ford: D.L. Boggs, H.S. Hilbert, M.M. Schechter. SAE-Paper 950089 15% (BSFC)
Conclusion: for a 1.6L-14 engine the later intake valve closing improved the 14, Late IVC
BSFC by 15% (10% EGR).
MAZDA / Kanesaka Tl: T. Goto, K. Hatamura, S. Takizawa, N. Hayama, H 10 ~ 15%
Abe, H. Kanesaka. SAE-Paper 940198 Fuel
Conclusion: A 2.3L-V6-4V boosted engine with a Miller cycle (late intake Efficiency,
valve closing) has a 10-15% higher fuel efficiency compared to natural Miller cycle
aspiration (NA) engine with same maximum torque. 25% reduction in friction
loss because of lower displacement. Expected 13% increase in fuel
consumption of 2.3L Miller engine compared to 3 3L NA engine
. v
Mitsubis hi: K. Hatano, K. Iida, H. Higas hi, S. Murata. SAE-Paper 930878 Up to 16% in
Conclusion: A 1.6L-14-4V engine reached an increase in fuel efficiency up to FC
16% Japanese Test Driving CYcle) and an power increase of 20%. 20% Power
~ . ~ , .
Honda/Nissan/ : S. Shiga; S. Yagi; M. Morita; T. Matsumoto; H. Nakamura; Up to 7%
T. Karasawa SAE-Paper 960585 Fuel
Conclusion: For a 0.25L-11-4V test engine an early closing of the intake Efficiency
valve results in up to 7% improvement in thermal efficiency
Ricardo: C. Gray SAE-Pager 880386 3 ~ 5°/O at part
Conclusion: Variable intake valve closing and cam timing duration improves load
part load fuel consumption by 3 ~ 5 %
158
EFFECTIVENESS AND IMPACT OF CORPORATE AVERAGE FUEL ECONOMY (CAFE) STANDARDS
l Variable Valve Timing and VariableValveLift(VVLT) | FClmprovement
From Base From Ref.
Technology Valve lift and valve timing controlled according to engine load and speed,
Description with step controlled mechanism
Primary Benefits | Less pumping losse ;: partially use intake valve liming and lift control for | l l
intake throttle control
Higher thermal efficiency: for better mixture formation with intake valve
throttling
Secondary Less pumping losses: engine down size with higher power density
Benefits
FC Improvement Base: 2V baseline engine Reference: VVT engine 5 ~ 10% 1 ~ 2 %
, ,
Example of Honda i-VTEC; Porsche Variocam Plus; Toyota VVLT-i
Application
..
Reference Honda: M. Matsuki, K. Nakano, T. Amemiya, Y. Tanabe, D. Shimizu, 1. 40% more
Ohmura SAE-Paper 960583 power with
Conclusion: for a 1.5L-14-4V engine the 3-stages VTEC technology (three same fuel
different cams) improved the power output by 40% with the same fuel consumption
consumption
Porsche: C. Brustle, D. Schwarzenthal. SAE-PAPER 980766 3-9%
Conclusion: for a B6-4V engine the fuel consumption could be reduced by
3-9% with variable valve lift
Meta: P. Kreuter, P. Heuser, J. Reinicke-Murmann, R. Erz, U. Peter. 11% to 15%
SAE-Paper 1999-01-0329 at idle
Conclusion: For a 2.0L-14-4V engine the VVLT system improved the fuel
efficiency by 11% to 15% in idle speed
Cylinder Deactivation | FC Improvement
From Base From Ref.
Technology Deactivate number of cylinders so that the active cylinders work on higher
Description BMEP level, normally valve deactivation is necessary
PrimarY Benefits The active cylinders have less Dumping loss with higher BMEP level
~ ~ . .
Secondary
Benefits
FC Improvement Base: 2V baseline engine Reference: VVTL engine 8 ~ 16% 3 ~ 6 %
. .
Example of Mercedes 5.0 L V8 and 6.0 L V12
Application
Reference Meta: P. Kreuter, P. Heuser, J. Reinicke-Murmann, R. Erz, P. Stein, U. 6-8% FC in
Peter. SAE-Paper 2001-01-0240 NEDC
Conclusion: A 14 engine with cylinder valve deactivation (CVD) showed 20%
improvement in fuel consumption at low engine speed. A V8 engine showed
6-8% improvement in fuel consumption for the New European Driving Cycle
Daimler-Chrysler: M. Fortnagel, G. Doll, K. Kollmann, H.-K. Weining. 6.5% FC in
RITZ 98 Sonderheft NEDC
Conclusion: A 5.0L-V8-V3 engine has an improvement of 6.5% fuel 10.3% FC in
consumption (New European Driving Cycle) and 10.3% in the FTP+HW FTP+HW
cycle with the cylinder deactivation
APPENDIX F
159
Engine Accessorylmprovement I FCimprovement
From Base From Ref.
Technology | Improving the efficiency of accessory components or their power I ~ ~
Description I transmission to real Ice the engine energy losses l l l
Primary Benefits Direct reduction of vehicle fuel consumption
Secondary Higher net output allows engine downsizing
Benefits
FC Improvement | Base: 2V baseline ~ ngine; Reference: 4V OHC engine | 3 ~ 7 % | 1 ~ 2 % |
Example of Less coolant flow rate, less oil flow rate
Application
Reference | "Technology and Cc it of Future Fuel Economy Improvements for Light-Duty | | 0.5 - ~ % |
Vehicles - Draft Final Report"; Energy and Environmental Analysis, Inc. - reduction in
HAS Report- June 4, 2001 fuel economy
Conclusions: Between 0.5 and 1% reduction in fuel economy is possible
Supercharging and Downsizing | FClmprovement I
From Base From Ref.
Technology | Reduce the engine c splacement and supercharge it for the required power | l
Descr~pbon
Primary Benefits Less pumping loss at low load conditions; less friction power loss at the
same FMEP; less Idle losses
Secondary | None l l
Benefits _
FC Improvement Base: 2V baseline engine; Reference: 4V OHC engine 7 ~ 12 % 5 ~ 7 %
Example of
Application
Reference FEV, Peter Walzer, 00ELE028 Future Engines For Cars 25%
Conclusions: Engine down size from 3L to 1.5L with supercharging and at part load,
VCR, part load specific fuel consumption improves by 25% with VCR
160
EFFECTIVENESS AND IMPACT OF CORPORATE AVERAGE FUEL ECONOMY (CAFE) STANDARDS
5-Speed Automatic Transmission | FC Improvement
From Base From Ref.
Technology | Added ratio places engine in better average speed/load operating point. | l
Description Improvements in torque converter lockup via Slip Controlled Converter
Clutch.
Improved internal oil pump losses by reducing pressure.
Closed-loop shift strategy.
Reduction of gear drag losses.
General weight reduction.
Primary Benefits | Less pumping loss at low load conditions; less friction power loss at the l l
same FMEP; lower Idle losses
Secondary | Improvedtransmissi~nefficiencies ~ l
Benefits
FC Improvement Baseline: 4-speed; Reference: 4-speed 2 ~ 3 % 2 ~ 3 %
Example of
Application
..
Reference SAE- 970689, "ZF 5-Speed Transmissions for Passenger Cars"; Heribert 5%
Scherer, Georg Gierer on combined
Auto 2000, "ZF 5-Speed Automatic Transmission"; Heribert Scherer M-H FTP-75
Conclusions: A 5% reduction can be attributed to the new 5-speed
transmission
Continuously Variable Transmission (CVT) | FC Improvement
From Base From Ref.
Technology Added ratio places engine in better average speed/load operating point.
Description Elimination of torque converter with an optimized starting clutch procedure.
Reduced work loss in the drive train and accessories due to the gear ratio
characteristics unique to the CVT
Primary Benefits Less pumping loss at low load conditions; less friction power loss at the
same PREP lower Idle losses
.
Secondary Improved drive train and accessory losses
Benefits
FC Improvement ~ Baseline: 4-speed, 1 eference: 5-speed ~ 6 - 1 1 % | 4 ~ ~ %
Example of Audi A4- Multitronic
Application
Reference ~ ATZ 8&9/2000, "Mu itronic - The New Automatic Transmission from Audi - | l
Parts 1 & 2"
SAE 970685, "ECOTRONIC - Continuously Variable ZF Transmission
(CVT);" Manfred Boos and Herbert Dozer
SAE 1999-01-0754, "Development of an Engine-CVT Integrated Control 9.3%
System;" S. Sakaguchi, E. Kimura, K. Yamamoto on MVEG
Conclusions: A 9.3% reduction can be attributed to the CVT transmission
6-Speed Automatic Transmission I FC Improvement
From Base From Ref.
Technology | Added ratio places I ngine in better average speed/load operating point. | l l
Description Improved gearbox efficiency with outstanding direct drive efficiency and
reduced gear drag losses.
Improved internal oil pump losses by internally geared wheel-pump and
improved volumetric efficiency and reduced leakage losses.
Optimized oil supply with reduced leakage in the hydraulic controls and
gearbox.
Primary Benefits Less pumping loss at low load conditions; less friction power loss at the ~-
same FMEP; less idle losses
Secondary | Improvedtransmissi in efficiencies I I
Benefits
FC Improvement Baseline: 4-speed, Reference: 5-speed 3 ~ 5 % 1 ~ 2 %
Example of BMW 7-Series
Application
Reference ATZ 9/ 2000, "6-Speed Automatic Transmission for the New BMW 7- 5%
Series;" Wolfgang Hall, Christian Bock on combined
Conclusions: A 5% reduction can be attributed to the new 6-speed M-H FTP-75
transmission
APPENDIX F
161
Aggressive Shift Logic | FC Improvement
From Base From Ref.
_
Technology Improvements in torque converter lockup.
Descriptions Closed-loop shift control strategy
Primary Benefits Reduced transmission losses
Second lary None
Benefits
FC Improvement Baseline: 4-speed Reference: 5-speed 3 ~ 6 % 1 ~ 3 %
,
Examl ale of
Application
, Reference | `'Techno~ogyandC(stofFutureFuelEconomylmprovementsforLight-Duty | ~ 9.0-9.3%
Vehicles - Draft Final Report"; Energy and Environmental Analysis, Inc. - improvement
NAS Report - June 4, 2001 in Fuel
Conclusions: A 9%-9.3% reduction can be attributed to aggressive shift logic Economy
with a 5-speed transmission
162
EFFECTIVENESS AND IMPACT OF CORPORATE AVERAGE FUEL ECONOMY (CAFE) STANDARDS
l Aerodynamic Drag Reduction | FClmprovement
From Base From Ref.
Technology | Aerodynamic drag reduction via vehicle shape changes or reduced frontal
Descr~pbon area
Primary Benefits Reduced higher speed engine load required
Secondary None
Benefits
FC Improvement Baseline: conventional vehicles; Reference: conventional vehicles 1 ~ 2 % 1 - 2 %
Example of
Application
Reference "Technology and Cost of Future Fuel Economy Improvements for Light-Duty 1.6 to 2.2%
Vehicles - Draft Final Report"; Energy and Environmental Analysis, Inc. - fuel economy
NAS Report- June 4, 2001 reduction
Conclusions: A 10% drag reduction is possible with a result in 1.6 - 2.2 %
FE reduction.
Improve Rolling Resistance | FClmprovement
From Base From Ref.
| Technology | Reduced bearing, b eke and driveline rotating forces. Improvements in tire | l
Description rolling resistances through new tread designs and tire carcass
improvements
Primary Benefits Reduced engine load required over entire speed range
Secondary None
Benefits
FC Improvement Baseline: conventional vehicles Reference: conventional vehicles 1 ~ 1.5 % 1 ~ 1.5 NO
. ,
Example of
Application
. .
Reference "Technology and Cost of Future Fuel Economy Improvements for Light-Duty 1.6 to 2.2%
Vehicles - Draft Final Report"; Energy and Environmental Analysis, Inc. - fuel economy
NAS Report- June 4, 2001 reduction
Conclusions: A 10% rolling resistance reduction is possible with a result in
1.5 - 2.0 % FE reduction
Safety Weightlncrease I FClmprovement I
From Base From Ref.
Technology Added weight to account for anticipated future safety structure, equipment
Description or other features
Primary Benefits Increased engine load required
Secondary None
Benefits
FClmprovement | Baseline:conventiol~alvehicles,Reference: conventionalvehicles I 3~ 4% | -3~-4%
Example of
ADDIication
. ~
Reference "Technology and Cost of Future Fuel Economy Improvements for Light-Duty 3 to 4%
Vehicles - Draft Final Report"; Energy and Environmental Analysis, Inc. - increase
NAS Report- June 4, 2001
Conclusions: 10% weight reduction results in 6.6 to 8% reduction in FE.
With a safety weight increase of 5% the committee used 3 to 4% FE
reduction to account for this.
APPENDIX F
163
intake Valve Throbbing
FC improvement
From Ref.
From Base
Technology
Description
Primary Benefits
Electronic or hydraulically controlled, mechanically actuated continuous
variable valve timing and lift
v
Less pumping losses: much less, or no, intake throttling for load control.
Higher thermal efficiency: better mixture formation with intake valve
throttling.
Less friction: higher mechanical efficiency due to higher engine IMEP.
Less pumping losses: engine down size with higher power density
Base: 2V baseline engine; Reference: VVT engine
Secondary
Benefits
FC Improvement
.
Example of
Application
Reference
8~16%
3~6%
BMW Valvetronic
MTZ 10 2001, pp. 826-835
Conclusion: Valvetronic creates a fuel consumption reduction of 12% part
load; 20% in idle; 14% reduction of fuel consumption for MVEG 111 compared
to its predecessor.
Delphi: R.J Pierik, J.F. Burkhard
SAE Paper 2000-01-1221
Conclusion: demonstrated brake specific fuel consumption (BSFC) of 12%
at idle, 7-10% at low middle load, and 0-3% at middle to high load.
20% idle
12% part load
14% MVEG 111
Idle: 12%
low: 7%
mid: 10%
high: 0-3%
(BSFC)
Idle: 30%
low: 3-4%
part load: 5%
high: 0%
torque: 9.8%
Hyundai / Siemens: J. Lee, Ch. Lee, J.A. Nitkiewicz
SAE-Paper 950816
Conclusion: For a 2.0L DOHC engine the fuel efficiency could be increased
by 30% in idle; 3-4% in low speed; 5% in part load with "lost motion"
technology. It uses conventional cam and create lost motion with hydraulic
mechanism.
.
BMW: R. Fierl, M Kluting
SAE-Paper 2000-01-1227
Conclusion: The electromechanical valve train offers a reduction in fuel
consumption by about 10% plus 5% higher peak torque.
Nissan: S. Takemura, S. Aoyama, T. Sugiyama, T. Nohara, K. Moteki, M.
Nakamura, S. Hara
SAE-Paper 2001-01-0243
Conclusion: A variable actuation system showed fuel consumption of nearly
10%
University of Bucharest: N. Negurescu, C. Pana, M.G. Popa, A. Racovitza
SAE-Paper 2001-01-0671
Conclusion: For a one-cylinder test engine WT increases the efficiency by
10to29%
0%
10%
1 0-29%
efficiency
164
-
EFFECTIVENESS AND IMPACT OF CORPORATE AVERAGE FUEL ECONOMY (CAFE) STANDARDS
Cam~ess Valve Actuation FC improvement
From Base From Ref.
Technology Completely variable valve timing controlled and actuated by electromagnetic
Description or high-pressure hydraulic means
Primary Benefits Less pumping losses: completely eliminate intake throttling valve for load
control
Higher thermal efficiency: higher compression ratio with less knocking
tendency; better mixture formation with intake valve throttling
Less friction: less valve train friction; higher mechanical efficiency due to
higher engine IMEP
Secondary | Less pumping losses: engine down size with higher power density l l
Benefits
FC Improvement Base: 2V baseline engine; Reference: VVT engine 10 ~ 20% 5 ~ 10%
Example of FEV EMV; Siemens EVT
Application
Reference FEV: M. Pischinger, W. Salber, F. van der Staay, H. Baumgarten, H. 16%
Kemper with EMV
FISITA- Seoul 2000
Conclusion: a reduction of 16% fuel consumption can be achieved by using
the EMV-technology in a 1.6L-14-4V engine
Variable Compression Ratio (VCR)
From Base
FC improvement
.
From Ref.
2 ~ 6 onto
Technology
Description
Using higher compression ratio at low load condition for high thermal
efficiency and low compression ratio at high load conditions to avoid
knocking. Normally applies to supercharged-down size engines.
Higher thermal efficiency at part load conditions
None
Primary Benefits
Secondary
Benefits
FC Improvement
Base: 2V baseline engine; Reference: 4V OHC engine and supercharge
. .
c own slang
SMB VCR engine
9~18%
Example of
Application
Reference
Saab: H. Drangel, L. Bergsten
Aachen Kolloquium 2000
Conclusion: With the combination VCR / high charging and downsizing of
the engine, it was possible to get the same power out of an 1.6L-15-4V
engine as a 3.0L-V6 engine. The resulting fuel consumption reduction is
30%
Daimler-Benz: F. G. Wirbeleit, K. Binder, D. Gwinner
SAE-Paper 900229
Conclusion: In a V8 a VCR between 8 to 13.9:1 depending on the engine
speed, the fuel consumption improves by 4% to 8%
Ford/University of Dar es Salaam: T. H. Ma, H. Rajbu
SAE-Paper 884053
Conclusion: At 1,500 rpm and 2 bar BMEP condition, VVT alone achieves
. 8% BSFC; WT+VCR achieves 19%
30%
4% - 8%
11 % BSFC
(1,500 rpm
and 2 bar
BMEP)
APPENDIX F
165
Automated Shift ManualTransmission I FClmprovement
From Base From Ref.
Technology Improved gearbox efficiency with improved efficiency and reduced gear drag
Descriptions losses.
Elimination or significant reductions of internal oil pump losses.
PrimarY Benefits Improved transmission efficiency-
, . ,
Secondary None
Benefits
FC Imorovement Baseline: 4-sceed Reference: 6-speed 6 ~ 10 % 3 ~ 5 %
. . .
Example of
Application
Reference SAE Toptec- Modern Advances in Automatic Transmission Technology, Estimated
"EMAT - Electromechanical Automatic Transmission"; D. Carriere, J. 10%
Cherry, R. Reed, Jr. Improvement
Conclusions: An estimated 10% improvement in fuel efficiency with in fuel
improved performance efficiency
Advanced CVT's (Allows Higher Torque) FC Improvement
From Base From Ref.
Technology | Improved transmiss on efficiency using toroidal-shape and roller elements | l
Description and special traction fluids.
Permits use in higher torque applications.
Primary Benefits Improved transmission efficiency.
Brings CVT to higher torque applications.
Secondary None
Benefits
FC Improvement Baseline 4-speed; Reference: CVT 6 ~ 13 % 0 ~ 2 %
Example of
Application
Reference Mazda's Future - Cars and Technology for Tomorrow 20%
Conclusions: A 20% improvement in fuel economy in the Japanese 10-15 Improvement
mode compared with a current 4-speed automatic transmission in fuel
economy
166
EFFECTIVENESS AND IMPACT OF CORPORATE AVERAGE FUEL ECONOMY (CAFE) STANDARDS
Integrated Starter Generator with idle Off | FC improvement
From Base From Ref.
Technology Integrated starter generator (ISG) cuts off fuel supply at idle and when the
Description brakes are applied. Greater starter power enables the engine to be started
immediately at higher speed.
Primary Benefits Less fuel loss when engine Dower is not necessary
, ~ . ,
Secondary None
Benefits
FC Improvement Base: 2V baseline engine Reference: 4V OHC engine 6 ~ 12 % 4 ~ 7 %
. ,
Example of
Application
—e ference "Technology and Cost of Future Fuel Economy Improvements for Light-Duty 9 to 11% FE
Vehicles - Draft Final Report"; Energy and Environmental Analysis, Inc. - improvement
NAS Report- June 4, 2001
Conclusions: Technology will provide for idle off, launch assist, improved
power generation with a 9% - 1 1% FE improvement.
42 V Electrical System | FC Improvement I
From Base From Ref.
Technology | Changing the vehicle operation voltage from 12V into 42V permitting l l l
Descriptions electronically controlled thermal management (water pump). Enabling
technolonv for 42V ISG.
,
Primary Benefits Less electrical power losses with less current flow through wires; higher
efficiency of the electrical components
Secondary Enables higher efficiency ISG systems
Benefits
FC Improvement Base: 2V baseline engine Reference: 4V OHC engine 3 ~ 7 % 1 ~ 2 %
,
Exams ale of
Apelication
.
Reference "Wards Engine and Vehicle Technology Update," June 15, 2001, p. 7 5% FE
Conclusions: Potential for electronic thermal management is 5% FE improvement
l Electric Power Steering | FC Improvement
From Base From Ref.
Technology Using electric motor to drive power steering
Description
Primary Benefits Reduced parasitic losses due to optimized operation (only when needed)
Second lary None
Benefits
| FC Improvement | Base: 2V baseline engine; Reference: 4V OHC engine | 3.5 ~ 7.5 % | 1.5 - 2.5 %
Example of
Application
Reference | ZF Lenksysteme: D. Peter, R. Gerhard | | 2- 3%
SAE-Paper 199-01-0401
Conclusion: Reduction of fuel consumption by 2-3% by using electrical
power steering instead of hydraulic power steering for a medium-sized
vehicle.
.
