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Effect of Octane Number on the Performance of Euro 5 and Euro 6 Gasoline Passenger Cars

ExxonMobil Research and Engineering Co.-Carole A. Bontoft
BP International Ltd.-John Williams
Published 2017-03-28 by SAE International in United States
Research Octane Number (RON) and Motor Octane Number (MON) are used to describe gasoline combustion which describe antiknock performance under different conditions. Recent literature suggests that MON is less important than RON in modern cars and a relaxation in the MON specification could improve vehicle performance. At the same time, for the same octane number change, increasing RON appears to provide more benefit to engine power and acceleration than reducing MON. Some workers have advocated the use of an octane index (OI) which incorporates both parameters instead of either RON or MON to give an indication of gasoline knock resistance. Previous Concawe work investigated the effect of RON and MON on the power and acceleration performance of two Euro 4 gasoline passenger cars during an especially-designed acceleration test cycle. A large number of fuels blended with and without oxygenates and ranging from around 95 to 103 RON and sensitivities (RON minus MON) up to around 15 were tested. The results were vehicle dependent but in general, showed that sensitivity and octane index appear to be…
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Effects of Fuel Property Changes on Heavy-Duty HCCI Combustion

ExxonMobil Research and Engineering Co.-Paul W. Bessonette, Charles H. Schleyer
Caterpillar Inc.-Kevin P. Duffy, William L. Hardy, Michael P. Liechty
Published 2007-04-16 by SAE International in United States
Homogeneous charge compression ignition (HCCI) offers the potential for significant improvements in efficiency with a substantial reduction in emissions. However, achieving heavy-duty (HD) HCCI engine operation at practical loads and speeds presents numerous technical challenges. Successful expansion of the HCCI operating range to include the full range of load and speed must be accomplished while maintaining proper combustion phasing, control of maximum cylinder pressure and pressure rise rates, and low emissions of NOx and particulate matter (PM). Significant progress in this endeavour has been made through a collaborative research effort between Caterpillar and ExxonMobil.This paper evaluates fuel effects on HCCI engine operating range and emissions. Test fuels were developed in the gasoline and diesel boiling range covering a broad range of ignition quality, fuel chemistry, and volatility. All fuels were evaluated in a Caterpillar 3401E Single Cylinder Oil Test Engine (SCOTE) under HCCI conditions. Exhaust emissions and engine performance were measured as a function of key engine variables, including engine speed, amount of exhaust gas recirculation (EGR), and fuel injection timing. The results show that…
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Measurement of Laminar Burning Velocity of Multi-Component Fuel Blends for Use in High-Performance SI Engines

ExxonMobil Research and Engineering Co.-Matthew I. Watkins, Noyes L. Avery
Colorado State University-Rudolf H. Stanglmaier
Published 2003-10-27 by SAE International in United States
A technique was developed for measuring the Laminar Burning Velocity (LBV) of multi-component fuel blends for use in high-performance spark-ignition engines. This technique involves the use of a centrally-ignited spherical combustion chamber, and a complementary analysis code. The technique was validated by examining several single-component fuels, and the computational procedure was extended to handle multi-component fuels without requiring detailed knowledge of their chemical composition. Experiments performed on an instrumented high-speed engine showed good agreement between the observed heat-release rates of the fuels and their predicted ranking based on the measured LBV parameters.
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Gasoline Type and Engine Effects on Equilibrium Combustion Chamber Deposits (CCD)

ExxonMobil Research and Engineering Co.-S. R. Kelemen, M. Siskin, N. L. Avery, K. D. Rose
University of Utah-M. Solum, R. J. Pugmire
Published 2001-09-24 by SAE International in United States
The behavior of equilibrium combustion chamber deposits (CCDs) was examined in Honda generator engines. The initial rapid CCD build-up was followed by a slower period of growth until an equilibrium level was reached after about 240 hours. The chemical composition of these CCDs follow the same compositional trends originally established for a range of vehicle CCDs produced up to 20,000 miles. The mean CCD thickness was related to the total CCD weight obtained from end of test samples. Differences were found in the equilibrium CCD thicknesses among base fuel and gasoline additives. The range of the mean CCD thickness was 155 microns to 240 microns. Three different experimental additives gave equilibrium CCD thickness that were 2% below, 1% above and 22% above the corresponding base fuel. The mean equilibrium CCD thickness for a commercial additive package was 8% above the corresponding base fuel. Analyses of equilibrium CCD thickness changes at individual sampling locations identified active regions on the piston tops near the cylinder wall and by the exhaust valve near the cylinder wall. Other selected…
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Mechanism of the Smokeless Rich Diesel Combustion by Reducing Temperature

ExxonMobil Research and Engineering Co.-Anthony M. Dean
Toyota Central R&D Labs. Inc.-Kazuhiro Akihama, Yoshiki Takatori, Kazuhisa Inagaki
Published 2001-03-05 by SAE International in United States
Recently, the smokeless rich diesel combustion had been demonstrated [1]. This can realize smokeless and NOx-less combustion by using a large amount of cooled EGR under a near stoichiometric and even in a rich operating condition. We focus on the effects of reducing diesel combustion temperature on soot reduction. In this paper, the smoke suppression mechanism in the smokeless rich combustion, where the temperature is reduced by higher EGR rate, is analyzed by the following procedure. (1)ϕ (equivalence ratio) - T (temperature) map, which shows soot formation tendencies as a function of ϕ and T, was made using zero dimensional calculations with a detailed chemical kinetic model including PAH (polycyclic aromatic hydrocarbons) formation, soot particle nucleation, growth and surface oxidation.(2)The combustion processes of the smokeless and conventional diesel combustion were simulated by the 3D-CFD KIVA2 code.(3)In-cylinder conditions of smokeless and conventional combustion predicted by 3D-CFD were plotted on the ϕ -T map to investigate their behaviors and differences on the map. The following results were obtained. (a)According to 3D-CFD, there is little difference in mixture…
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Performance of an Advanced Synthetic Diesel Engine Oil

ExxonMobil Research and Engineering Co.-K. J. Kelly, S. Kennedy, J. E. Spagnoli
Published 2000-06-19 by SAE International in United States
This paper describes the performance of a synthetic diesel engine oil formulated to satisfy the most demanding lubrication requirements of modern heavy-duty diesel engines designed to meet North American and European emission regulations. The combination of an advanced fully synthetic base stock system and a customized additive system has resulted in an SAE 5W-40 oil with unique performance characteristics which include exceptional low and high temperature properties, excellent engine performance in laboratory and field tests, and an independently-documented, measurable fuel economy benefit relative to conventional mineral-based multigrade diesel engine oils. In addition to the cold starting and low volatility benefits derived from the synthetic base stocks, this technology has demonstrated outstanding engine performance in the areas of soot dispersancy, wear protection, engine cleanliness, and oil consumption control. This synthetic diesel engine oil exceeds the requirements of the API CH-4 and ACEA E4/E5 categories, as well as a number of more demanding North American and European engine builder specifications. Engine performance in the laboratory tests required to satisfy these specifications is presented, as well as extended…
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