It takes its name from the C ooperative F uel R esearch Committee, which developed the method and the engine. A CFR test engine has up to four tanks, which can be individually switched with the engine running. Status: December All information subject to change.
Errors and omissions excepted. Important Terms from A to Z. Organic Chemicals. The reason for using normal heptane and iso-octane was because they both have similar volatility properties, specifically boiling point, thus the varying ratios to should not exhibit large differences in volatility that could affect the rating test.
My Books. Discover Free Online Books. However, the EPA declaration and associated study findings are not mandates, and each vehicle manufacturer has the discretion to recommend E15 use in their vehicles. Additionally, new fuel dispenser installs in the U. From an engine technology standpoint, downsize and downspeed have taken hold in the U. Additionally, technology like cylinder deactivation has gained a non-trivial market share Alson et al.
The approach holds total engine output fixed by eliminating fueling and combustion in some cylinders while increasing the load in the remaining fired cylinders.
However, in variable displacement approaches, the fact that the fired cylinders can become knock-limited reduces the potential of this approach to increasing fuel economy Leone and Pozar, The present study has focused on SI engines, yet other engine technologies exist that have increased engine efficiencies and, thus, have improved fuel economy. A well-known mature engine technology is the compression ignition engine. Conventional compression ignition combustion engines i.
Additionally, new unconventional thermodynamic compression ignition cycles have been suggested to achieve fuel economy improvements from reduced heat transfer losses [i. Although conventional or new unconventional compression ignition engines offer high fuel economy potential Akihama et al.
However, recent studies have shown that diesel-like engine efficiencies have been demonstrated through advanced or low-temperature combustion concepts. These include some approaches that use SI-type engine designs or gasoline-like fuels, making them more akin to the majority of current and historical light-duty powertrains.
Presently, there are many competing methods for achieving this. Some examples that have been investigated include advanced combustion strategies Kimura et al. Although low-temperature combustion concepts are all very relevant and promising, the near-term deployment of them remains to be fully proven. An alternative approach to reduced combustion temperatures and increase engine efficiency is through air or cooled exhaust gas recirculation EGR dilution in an SI engine i.
Studies with homogeneous and stratified mixtures using air Harada et al. The technical, economic, and regulatory aspects of reduced temperature combustion through advanced or highly dilute SI approaches remain to be proven in the market, but the trends in Figure 10 suggest that the technology cost and performance must balance for adoption.
Regardless of whether adoption of these high-efficiency engine strategies is possible, it has been shown that advanced combustion and highly dilute SI engine concepts are compatible with and even can offer improved efficiency potential with high-octane-number gasoline—ethanol fuel blends, suggesting that increases in fuel octane number will not prevent adoption of these strategies in the future Splitter et al.
Hybridization combines engines and electric motors as a way to leverage positive attributes of each technology, including an enabling path for moving engine operating conditions to high-efficiency areas. To do so, hybrid powertrains virtually eliminate low-load engine operation and result in engine operation at or close to the knock limit. Thus, if engine efficiency can be increased through compression ratio enabled by fuel AKI increase, hybrid powertrains can leverage and compound engine efficiency increases to even further improve fuel economy.
This ability illustrates that hybrid powertrains are complementary to high efficiency or advanced combustion concepts. However, unlike advanced combustion concepts, hybrid technologies have been in the market in excess of 10 years Alson et al. Thus, it is appropriate and possible to evaluate the consumer, regulatory, and technical factors expressed in the trend relative to hybrids Figure There is little argument that hybrid cars can be class leaders in fuel economy Alson et al.
As a result, hybrid sales tend to be proportional to near-term economic factors, such as fuel price. Figure 14 illustrates this trend in terms of monthly hybrid sales relative to monthly market fuel price, which shows that hybrid sales correlated strongly with market fuel price i. Although this trend is strong, there were two instances when the correlation deviated, but both can be explained by regulation and market factors that influenced consumer choice or availability.
Average market trends, hybrid sales, and unleaded fuel price. Data are from EIA and hybridcars. Energy Information Administration, ; Cobb, The first deviation occurred in , when hybrid sales increased even though fuel price decreased; the Car Allowance Rebate System National Highway Traffic Safety Administration, was in effect i.
The second deviation occurred in , when hybrid sales declined even though fuel prices increased; this anomaly can be attributed to the limited supply of hybrid system components that was caused by the Tohoku earthquake and tsunami that struck Japan, temporarily cutting resources and operations at Japanese suppliers and OEMs, in particular Toyota Trefis Team, Ignoring these two disturbances, the overall trend is quite good and that with flat or decreasing market fuel price, it seems unlikely that un-incentivized hybrid sales alone will meet aggressive CAFE targets.
Hybrid powertrains are not independent of, but rather work in tandem with, engine advancement. For example, the Toyota Prius, continually the best-selling hybrid vehicle in the U. Just as future gains in engine efficiency will improve hybrid vehicle efficiency, electrification has and will continue to complement internal combustion engine strategies and technologies Kleeberg et al.
Based on this, if engine technology improves, the market competition between electrification and combustion will continue. Their data show that while battery prices have slowly begun to decline nearing price competitiveness of battery-electric vehicles , future gains in engine efficiency improve the competitiveness of combustion powertrains, including conventional, hybrid, and plug-in hybrid systems. Thus, there is a feedforward mechanism for engine efficiency improvements that can migrate into hybrid powertrains, and ultimately into consumer preferences.
The effect that this has on the trajectory in Figure 10 is uncertain, but the data in Figures 10 and 14 support the theory that without direct regulatory action, consumer economic preference will likely be the near-term deciding factor in hybrid market adoption. Analysis showed that consumer, technical, and regulatory bodies all affect the light-duty U. Specifically, since there have been five definable ages of development.
During each age, there have been critical factors that have affected the immediate co-evolution of fuels and engines. Therefore, this trend appears to at least somewhat capture or account for consumer, technical, and regulatory body actions throughout history. Based on this long-term trajectory and interdependence of controlling factors in the light-duty market, the continued improvement to transportation efficiency per unit power will require continued co-evolution of fuels and engines.
The historical analysis presented in this work shows that fuel octane can be an enabler for increasing engine efficiency. Until the s, co-evolution of fuels and engines occurred from improvements to fuel refining technologies and octane improvement through TEL addition. However, since fuel lead removal began in the mids, fuel octane number has remained stagnant while engine efficiency and performance improvements have resulted from digital controls and design refinements.
This relaxation of the fundamental coupling between fuel octane number and engine compression ratio is a long-term unsustainable trajectory, as for a given octane number engine compression ratio will ultimately be limited by available technologies. Recent regulations that further reduce CO 2 emissions present new challenges to improve engine and vehicle efficiencies that have prompted the need to reexamine if and how fuel consumption could decrease through increasing fuel octane number.
It was found the incremental increase in fuel ethanol content from E10 to E15 and E10 to E25 could enable fuel octane number to increase from 87 to 90 AKI and 92 to 95 AKI for regular and premium grades, respectively. Additionally, these finished fuels could be achieved by blending ethanol with base stock fuel octane numbers identical to those historically used for leaded fuels.
Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this manuscript, or allow others to do so, for the United States Government purposes. The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
Please note that reproduction and use of this data and analysis is unlimited for personal not for profit means with proper citation of the original data source, the present manuscript including acknowledgment of the analysis presented herein. Reproduction for the data or present analysis for commercial publication, and or for profit means or other means than personal use, is unauthorized without consent of the authors.
CRC Report No. Atlanta, GA, Google Scholar. Akihama, K. Alger, T. SAE Int. Engines 1, — Dedicated EGR: a new concept in high efficiency engines. Engines 2, — Alson J. Atlanta, GA, p. Atlanta, GA. Armstrong, J. Austin, T. SAE Technical Paper. Balouet, J.
Applied dendroecology and environmental forensics. Characterizing and age dating environmental releases: fundamentals and case studies. Forensics 8, 1— Bandel, W. Belzowski, B. Report No. Benson, J. Blumberg, P. Prediction of NO formation in spark-ignited engines — an analysis of methods of control. Boyd, T. Pathfinding in Fuels and Engines. Brown, L. Gasoline and alcohol-gasoline blends. Campau, R. Low Emission Concept Vehicles. Campbell, J. Canfield, R. Caris, D. Mechanical Octanes for Higher Efficiency.
Caton, J. The thermodynamic characteristics of high efficiency, internal-combustion engines. Energy Convers. Cheah, L. The trade-off between automobile acceleration performance, weight, and fuel consumption. Fuels Lubr. Cobb, J. Data from: May Dashboard. Com Monthly Sales Dashboard. Available from: HybridCars. Cummings, H. Methods of Measuring the Antiknock Value of Fuels. Dec, J. Engines 3, — Dempsey, A. Dickson, C. Trends of Petroleum Fuels.
Topical Report No. Bartlesville, OK: National Inst. Edgar, G. Measurement of knock characteristics of gasoline in terms of a standard fuel1. Egloff, G. Symposium on motor fuels alcohol-gasoline as motor fuel. Energy Information Agency. Refiner Motor Gasoline Sales Volumes. Monthly Energy Review, Renewable Energy. Annual Energy Outlook EPA Website. Federal Register. Ferfecki, F.
Urbana, IL: Illinois Univ. Foong, T. The octane numbers of ethanol blended with gasoline and its surrogates. Fuel , — Forster, E. Foster, D. Fraser, N. Challenges for increased efficiency through gasoline engine downsizing. Available at: Fueleconomy. Gao, Z. Drive cycle simulation of high efficiency combustions on fuel economy and exhaust properties in light-duty vehicles. Energy , — Gibbs, L. Gasoline additives — when and why. SAE Trans. How Gasoline Has Changed. Greene, D. Motor fuel choice: an econometric analysis.
Part A Gen. Hanipah, M. Recent commercial free-piston engine developments for automotive applications. Harada, J. Development of Direct Injection Gasoline Engine. Hastings, J. In the early 20th century, automotive manufacturers were searching for a chemical that would reduce engine knock.
In , automotive engineers working for General Motors discovered that tetraethyl lead better known as lead provided octane to gasoline, preventing engine knock. While aromatic hydrocarbons such as benzene and alcohols such as ethanol were also known octane providers at the time, lead was the preferred choice due to its lower production cost.
Leaded gasoline was the predominant fuel type in the United States until the U. Environmental Protection Agency EPA began phasing it out in the mids because of proven serious health impacts.
Early in its use as a fuel additive, health concerns were raised regarding the use of lead in gasoline. In , 15 refinery workers in New Jersey and Ohio died of suspected lead poisoning. As a result, the Surgeon General temporarily suspended the production of leaded gasoline and convened a panel to investigate the potential dangers of lead use in gasoline.
Despite these warnings, the Surgeon General set a voluntary standard of lead content, which the refining industry successfully met for decades. It was not until the s, following extensive health research, that the devastating health impacts of low-level lead exposure were established.
The health impacts of lead exposure in children include anemia, behavioral disorders, low IQ, reading and learning disabilities, and nerve damage. In adults, lead exposure is associated with hypertension and cardiovascular disease.
Prior to the lead phase-out in gasoline, the total amount of lead used in gasoline was over , tons per year. Congress passed the Clean Air Act in , setting in motion the formation of the EPA and, ultimately, the removal of lead from gasoline.
EPA estimates that between and , 68 million children were exposed to toxic levels of lead from leaded gasoline alone. The phase-out of lead from gasoline subsequently reduced the number of children with toxic levels of lead in their blood by 2 million individuals a year between and The EPA is formed and given the authority to regulate compounds that endanger human health.
Lead damages the catalytic converters used in these new vehicles to control tailpipe emissions. Catalytic converters are still used in vehicles today. Lead is still used in some aviation fuels. Thanks to coordinated efforts, lead is now absent from gasoline in most of the world.
Following the lead phase-out in the United States, the oil refining industry chose to construct additional refining capacity to produce octane from other petroleum products, rather than from renewable sources such as ethanol.
RFG has an increased oxygenate content, which helps it burn more completely.
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