Download or read book Investigation of Knock Limited Compression Ratio of Ethanol Gasoline Blends written by and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Ethanol offers significant potential for increasing the compression ratio of SI engines resulting from its high octane number and high latent heat of vaporization. A study was conducted to determine the knock limited compression ratio of ethanol gasoline blends to identify the potential for improved operating efficiency. To operate an SI engine in a flex fuel vehicle requires operating strategies that allow operation on a broad range of fuels from gasoline to E85. Since gasoline or low ethanol blend operation is inherently limited by knock at high loads, strategies must be identified which allow operation on these fuels with minimal fuel economy or power density tradeoffs. A single cylinder direct injection spark ignited engine with fully variable hydraulic valve actuation (HVA) is operated at WOT conditions to determine the knock limited compression ratio (CR) of ethanol fuel blends. The geometric compression ratio is varied by changing pistons, producing CR from 9.2 to 13.66. The effective CR is varied using an electro-hydraulic valvetrain that changed the effective trapped displacement using both Early Intake Valve Closing (EIVC) and Late Intake Valve Closing (LIVC). The EIVC and LIVC strategies result in effective CR being reduced while maintaining the geometric expansion ratio. It was found that at substantially similar engine conditions, increasing the ethanol content of the fuel results in higher engine efficiency and higher engine power. These can be partially attributed to a charge cooling effect and a higher heating valve of a stoichiometric mixture for ethanol blends (per unit mass of air). Additional thermodynamic effects on and a mole multiplier are also explored. It was also found that high CR can increase the efficiency of ethanol fuel blends, and as a result, the fuel economy penalty associated with the lower energy content of E85 can be reduced by about a third. Such operation necessitates that the engine be operated in a de-rated manner for gasoline, which is knock-prone at these high CR, in order to maintain compatibility. By using EIVC and LIVC strategies, good efficiency is maintained with gasoline, but power is reduced by about 34%.

Download or read book Knock limited Performance of Ethanol Blends in a Spark ignition Engine written by and published by . This book was released on 1981 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental study was performed to determine the effect of varying percentages of ethanol in fuel using a CFR engine operated at knock-limited compression ratio and maximum power spark timing. Blends of 85 octane primary reference fuel and ethanol in concentrations between 10 and 25% by volume were tested for performance, fuel economy, and exhaust emissions. The results indicated that when the engine was operated at knock-limited conditions at a constant equivalence ratio, the use of ethanol resulted in a reduction in petroleum fuel usage of 10% greater than the volumetric percentage of the ethanol used in the blend. These results were independent of the amount of ethanol used in the blend. Under these conditions, as the ethanol concentration was increased, BMEP and BSHC increased, BSNO and BSCO remained essentially constant, and exhaust temperature decreased.

Download or read book The Effect of Compression Ratio on Knock Limits of High performance Fuels in a CFR Engine written by Henry E. Alquist and published by . This book was released on 1944 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: The knock-limited performance of blends of 0, 50, and 100 percent by volume of triptane (2,2,3-trimethylbutane) in 28-R fuel was determined with a modified F-4 engine at three sets of conditions varying from severe to mild at each of three compression ratios (6.0, 8.0, and 10.0). It was found that the knock limits of the triptane blend were more sensitive to compression ratio than that of 28-R fuel, and the sensitivities of the triptane blends to compression ratio, as measured by knock-limited indicated mean effective pressure, increased as the severity of other engine conditions increased.

Download or read book Comparison of Relative Sensitivities of the Knock Limits of Two Fuels to Six Engine Variables written by Harvey A. Cook and published by . This book was released on 1946 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt: A sensitive fuel and a relatively insensitive fuel were knock-tested in a full-scale air-cooled cylinder. Sensitivity was indicated by a different degrees of knock-limited response to changes in engine conditions. Six engine variables were investigated: (1) fuel-air ratio, (2) compression ratio, (3) inlet-air temperature, (4) spark advance, (5) exhaust pressure, and (6) cylinder temperature.

Download or read book Alcohol as an Alternative Fuel for Internal Combustion Engines written by Pravesh Chandra Shukla and published by Springer Nature. This book was released on 2021-05-15 with total page 273 pages. Available in PDF, EPUB and Kindle. Book excerpt: div="" This book covers different aspects related to utilization of alcohol fuels in internal combustion (IC) engines with a focus on combustion, performance and emission investigations. The focal point of this book is to present engine combustion, performance and emission characteristics of IC engines fueled by alcohol blended fuels such as methanol, ethanol and butanol. The contents also highlight the importance of alcohol fuel for reducing emission levels. Possibility of alcohol fuels for marine applications has also been discussed. This book is a useful guide for researchers, academics and scientists. ^

Download or read book High Compression Ratio Turbo Gasoline Engine Operation Using Alcohol Enhancement written by Raymond A. Lewis and published by . This book was released on 2013 with total page 62 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gasoline - ethanol blends were explored as a strategy to mitigate engine knock, a phenomena in spark ignition engine combustion when a portion of the end gas is compressed to the point of spontaneous auto-ignition. This auto-ignition is dangerous to the operation of an internal combustion engine, as it can severely damage engine components. As engine designers are trying to improve the efficiency of the internal combustion engine, engine knock is a key limiting factor in engine design. Two methods have been used to limit engine knock that will be considered here; retarding the spark timing and addition of additives to reduce the tendency of the fuel mixture to knock. Both have drawbacks. Retarding spark reduces the engine efficiency and additives typically lower the heating value of the fuel, requiring more fuel for a given operating point. To study this problem a turbocharged engine was tested with a variety of combinations of gasoline and ethanol, an additive with very good anti-knock abilities. Pressure was recorded and GT Power simulations were used to determine the temperature within the cylinder. An effective octane number was calculated to measure the ability of the fuel to resist knock. Effective octane numbers varied from 91 for UTG91 to 111 for E25, respectively. Engine simulations were used to extrapolate to points that couldn't be tested in the experimental setup and generate performance maps which could be used to predict how the engine would act inside of a vehicle. It was found that increasing the compression ratio from 9.2 to 13.5 leads to a 7% relative increase in part load efficiency. When applied in a vehicle this leads to a 2-6% increase in miles per gallon of gasoline consumption depending on the drive cycle used. Miles per gallon of ethanol used were significantly higher than gasoline; 141 miles per gallon of ethanol was the lowest mileage over all cycles studied.

Download or read book An Investigation of the Factors Influencing the Knock Limited Performance of a Variable Compression Ratio Dual Fuel Engine written by Arthur William Faulkner and published by . This book was released on 1971 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Vehicle and Automotive Engineering 2 written by Károly Jármai and published by Springer. This book was released on 2018-05-09 with total page 801 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents the proceedings of the second Vehicle Engineering and Vehicle Industry conference, reflecting the outcomes of theoretical and practical studies and outlining future development trends in a broad field of automotive research. The conference’s main themes included design, manufacturing, economic and educational topics.

Download or read book An Investigation of Factors Influencing the Knock limited Performance of a Variable Compression Ratio Dual Fuel Engine Using Gaseous Fuels with Pilot Injection written by Kamal Sadek Hanna Sadek and published by . This book was released on 1966 with total page 346 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Effect of Compression Ratio on Knock Limits of High performance Fuels in a CFR Engine written by Henry E. Alquist and published by . This book was released on 1945 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: The knock-limited performance of blends of 0, 50, and 100 percent by volume of 2,3-dimethylpentane in 28-R fuel was determined with a modified F-4 engine at three sets of conditions varying from severe to mild at each of three compression ratios (6.0, 8.0, and 10.0). The knock-limited performance of 2,3-dimethylpentane is shown to have about the same sensitivity to compression ration and inlet-air temperature as 28-R fuel. For all the conditions tested the knock-limited performance of 2,3-dimethylpentane ranges from 12 to 47 percent (average of 23 percent) higher than that of 28-R fuel.

Download or read book Performance and Knock Limits of Ethanol written by M. S. Radwan and published by . This book was released on 1985 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Advanced Combustion Techniques and Engine Technologies for the Automotive Sector written by Akhilendra Pratap Singh and published by Springer Nature. This book was released on 2019-10-10 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book discusses the recent advances in combustion strategies and engine technologies, with specific reference to the automotive sector. Chapters discuss the advanced combustion technologies, such as gasoline direct ignition (GDI), spark assisted compression ignition (SACI), gasoline compression ignition (GCI), etc., which are the future of the automotive sector. Emphasis is given to technologies which have the potential for utilization of alternative fuels as well as emission reduction. One special section includes a few chapters for methanol utilization in two-wheelers and four wheelers. The book will serve as a valuable resource for academic researchers and professional automotive engineers alike.

Download or read book The Knock limited Performance of Gasoline alcohol water Fuel Blends in a Spark Ignition Engine written by Walter R. McIlveen and published by . This book was released on 1975 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Effect of Compression Ratio on Knock Limits of High performance Fuels in a CFR Engine written by Henry E. Alquist and published by . This book was released on 1945 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: The knock-limited performance of blends of 0, 50, and 100 percent by volumne of 2,2,3-trimethylpentane in 28-R fuel was determined with a modified F-4 engine at three sets of conditions varying from severe to mild at each of three compression ratios (6.0, 8.0, and 10.0). A comparison of the knock-limited performance of 2,2,3-trimethylpentane with that of triptane (2,2,3-trimethylbutane) is included.

Download or read book Automotive Fuels Reference Book written by Paul Richards and published by SAE International. This book was released on 2014-03-05 with total page 870 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first two editions of this title, published by SAE International in 1990 and 1995, have been best-selling definitive references for those needing technical information about automotive fuels. This long-awaited new edition has been thoroughly revised and updated, yet retains the original fundamental fuels information that readers find so useful. This book is written for those with an interest in or a need to understand automotive fuels. Because automotive fuels can no longer be developed in isolation from the engines that will convert the fuel into the power necessary to drive our automobiles, knowledge of automotive fuels will also be essential to those working with automotive engines. Small quantities of fuel additives increasingly play an important role in bridging the gap that often exists between fuel that can easily be produced and fuel that is needed by the ever-more sophisticated automotive engine. This book pulls together in a single, extensively referenced volume, the three different but related topics of automotive fuels, fuel additives, and engines, and shows how all three areas work together. It includes a brief history of automotive fuels development, followed by chapters on automotive fuels manufacture from crude oil and other fossil sources. One chapter is dedicated to the manufacture of automotive fuels and fuel blending components from renewable sources. The safe handling, transport, and storage of fuels, from all sources, are covered. New combustion systems to achieve reduced emissions and increased efficiency are discussed, and the way in which the fuels’ physical and chemical characteristics affect these combustion processes and the emissions produced are included. There is also discussion on engine fuel system development and how these different systems affect the corresponding fuel requirements. Because the book is for a global market, fuel system technologies that only exist in the legacy fleet in some markets are included. The way in which fuel requirements are developed and specified is discussed. This covers test methods from simple laboratory bench tests, through engine testing, and long-term test procedures.

Download or read book Experiments on the Effects of Dilution and Fuel Composition on Ignition of Gasoline and Alternative Fuels in a Rapid Compression Machine written by Prasanna Chinnathambi and published by . This book was released on 2019 with total page 262 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the first part of this work, ignition of methane-air mixtures under excess air dilution is studied. When excess air is used in SI engine operation, thermal efficiency is increased due to increase in compression ratio together with reduced pumping and heat loses. However, stable operation with excess air is challenging due to poor flammability of the resulting diluted mixture. Hence in order to achieve stable and complete combustion a turbulent jet ignition (TJI) system is used to improve combustion of lean methane-air mixtures. Various nozzle designs and operating strategies for a TJI system were tested in a rapid compression machine. 10-90% burn duration measurements were useful in assessing the performance of the nozzle designs while the 0-10% burn durations indicated if optimal air-fuel ratio is achieved within the pre-chamber at the time of ignition. The results indicated that distributed-jets TJI system offered faster and stable combustion while the concentrated-jets TJI system offered better dilution tolerance.Knock in a SI engine occurs due to autoignition of the end gas mixture and typically occurs in the negative temperature coefficient (NTC) region of the fuel-air mixture. Dilution of intake charge with cold exhaust recirculation gases (EGR) reduces combustion temperatures and decreases mixture reactivity thereby reducing knocking tendency. This enables optimal spark timings to be used, thereby increasing efficiency of SI engines which would otherwise be knock limited. Effect of cold EGR dilution is studied in the RCM by measuring the autoignition delay times of gasoline and gasoline surrogate mixtures diluted with varying levels of CO2. The autoignition experiments in the RCM were performed using a novel direct test chamber (DTC) charge preparation approach. The DTC approach enabled mixture preparation directly within the combustion chamber and eliminated the need for mixing tanks. Effect of CO2 dilution in retarding the autoignition delay times was more pronounced in the NTC region, while it was weaker in the low temperature and high temperature regions. The retarding effect was found to be dependent on both the octane number and the fuel composition of the gasoline being studied.Finally, the effect of substituting ethanol(biofuel) in gasoline surrogates for up to 40% by volume is studied. Ethanol is an octane booster, but it blends antagonistically with aromatics such as toluene and synergistically with alkanes with respect to the resulting octane number of the blends. In order to study this blending effect, two gasoline surrogates containing only alkanes (PRF), and alkanes with large amounts of toluene (TRF) are blended with varying levels of ethanol. The ignition delay times of the resulting mixtures are measured in a rapid compression machine and kinetic analysis was carried out using numerical simulations. The kinetic analysis revealed that ethanol controlled the final stages of ignition for the PRF blends when more than 10% by volume of ethanol is present. However, in the TRF blends, toluene controlled the ignition until mole fractions of ethanol became higher than the toluene indicating the reason for the antagonistic blending nature. It was found that the RON values of the resulting blends matched the trend of the ignition delay times recorded at 740K and 21 bar compressed conditions. This enables qualitative assessment of the RON numbers for new biofuel blends by measuring their ignition delay times in the RCM.

Download or read book E85 Optimized Engine Through Boosting Spray Optimized DIG VCR and Variable Valvetrain written by and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The use of biofuels for internal combustion engines has several well published advantages. The biofuels, made from biological sources such as corn or sugar cane, are renewable resources that reduce the dependence on fossil fuels. Fuels from agricultural sources can therefore reduce a countries energy dependency on other nations. Biofuels also have been shown to reduce CO2 emissions into the atmosphere compared to traditional fossil based fuels. Because of these benefits several countries have set targets for the use of biofuels, especially ethanol, in their transportation fuels. Small percentages of ethanol are common place in gasoline but are typically limited to 5 to 8% by volume. Greater benefits are possible from higher concentrations and some countries such as the US and Sweden have encouraged the production of vehicles capable of operating on E85 (85% denatured ethanol and 15% gasoline). E85 capable vehicles are normally equipped to run the higher levels of ethanol by employing modified fuel delivery systems that can withstand the highly corrosive nature of the alcohol. These vehicles are not however equipped to take full advantage of ethanol's properties during the combustion process. Ethanol has a much higher blend research octane number than gasoline. This allows the use of higher engine compression ratios and spark advance which result in more efficient engine operation. Ethanol's latent heat of vaporization is also much higher that gasoline. This higher heat of vaporization cools the engine intake charge which also allows the engine compression ratio to be increased even further. An engine that is optimized for operation on high concentrations of ethanol therefore will have compression ratios that are too high to avoid spark knock (pre-ignition) if run on gasoline or a gasoline/ethanol blend that has a low percentage alcohol. An engine was developed during this project to leverage the improved evaporative cooling and high octane of E85 to improve fuel economy and offset E85's lower energy content. A 2.0 L production Direct Injection gasoline, (DIg) engine employing Dual Independent Cam Phasing, (DICP) and turbo charging was used as the base engine. Modified pistons were used to increase the geometric compression ratio from 9.2:1 to 11.85:1 by modifying the pistons and adding advanced valvetrain to proved control of displacement and effective compression ratio through valve timing control. The advanced valvetrain utilized Delphi's two step valvetrain hardware and intake cam phaser with increased phasing authority of 80 crank angle degrees. Using this hardware the engine was capable of operating knock free on all fuels tested from E0-E85 by controlling effective compression ratio using a Late Intake Valve Closing, (LIVC) strategy. The LIVC strategy results in changes in the trapped displacement such that knock limited torque for gasoline is significantly lower than E85. The use of spark retard to control knock enables higher peak torque for knock limited fuels, however a loss in efficiency results. For gasoline and E10 fuels, full effective displacement could not be reached before spark retard produced a net loss in torque. The use of an Early Intake Valve Closing, (EIVC) strategy resulted in an improvement of engine efficiency at low to mid loads for all fuels tested from E0- E85. Further the use of valve deactivation, to a single intake valve, improved combustion stability and enabled throttle-less operation down to less than 2 bar BMEP. Slight throttling to trap internal residual provided additional reductions in fuel consumption. To fully leverage the benefits of E85, or ethanol blends above E10, would require a vehicle level approach that would take advantage of the improved low end torque that is possible with E85. Operating the engine at reduced speeds and using advanced transmissions (6 speeds or higher) would provide a responsive efficient driving experience to the customer. The vehicle shift and torque converter lockup points for high ethanol blends could take advantage of the significant efficiency advantage of down-speeding and operating at higher loads to deliver the required power.