The Experts below are selected from a list of 6543 Experts worldwide ranked by ideXlab platform
Yasuo Moriyoshi - One of the best experts on this subject based on the ideXlab platform.
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performance and exhaust emission characteristics of a spark ignition engine using ethanol and ethanol reformed gas
2010Co-Authors: Cheolwoong Park, Young Choi, Changgi Kim, Gihun Lim, Yasuo MoriyoshiAbstract:Abstract Since ethanol is a renewable source of energy and has lower carbon dioxide (CO2) emissions than gasoline, ethanol produced from biomass is expected to be used more frequently as an alternative Fuel. It is recognized that for spark ignition (SI) engines, ethanol has the advantages of high octane and high combustion speed and the disadvantage of ignition difficulties at low temperatures. An additional disadvantage is that ethanol may cause extra wear and corrosion of electric Fuel Pumps. On-board hydrogen production out of ethanol is an alternative plan. Ethanol has been used in Brazil as a passenger vehicle Fuel since 1979, and more than six million vehicles on US highways are flexible Fuel vehicles (FFVs). These vehicles can operate on E85 – a blend of 85% ethanol and 15% gasoline. This paper investigates the influence of ethanol Fuel on SI engine performance, thermal efficiency and emissions. The combustion characteristics of hydrogen enriched gaseous Fuel made from ethanol are also examined. Ethanol has excellent anti-knock qualities due to its high octane number and a high latent heat of evaporation, which makes the temperature of the intake manifold lower. In addition to the effect of latent heat of evaporation, the difference in combustion products compared with gasoline further decreases combustion temperature, thereby reducing cooling heat loss. Reductions in CO2, nitrogen oxide (NOx), and total hydrocarbons (THC) combustion products for ethanol vs. gasoline are described.
Stephanie Watkins - One of the best experts on this subject based on the ideXlab platform.
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on the lubrication performance of external gear Pumps for aerospace Fuel delivery applications
2019Co-Authors: Divya Thiagarajan, Andrea Vacca, Stephanie WatkinsAbstract:Abstract External gear Pumps (EGPs) are one of the most common choices in aerospace engines as a Fuel delivery pump. These units usually include a pressure compensation system that defines the lubricating gap at the lateral side of the gears. This lubricating interface is a critical design aspect, which strongly affects the reliability as well as the mechanical and volumetric efficiencies of the pump. Major challenges in designing these lubricating gaps in aero engine Fuel Pumps, include high operating speeds, delivery pressures and low viscosity of the working fluids. Virtual prototyping methods present a fast and efficient design tool and have the potential to improve the EGP’s reliability and efficiency. This paper presents a study on the pressure compensation system of a Fuel delivery EGP and shows how the presence of frictional forces opposing the motion of the compensating element significantly affect the lubricating performance of the unit. The presence of these frictional forces produces an effect of hysteresis on the axial balance system, so that the lubricating gaps that develop within the pump at a certain operating condition depend on the previous operating state. This effect was captured in an experimental setup purposely developed for this study at Rolls-Royce. Within this work, this behavior was also reproduced numerically, through a coupled fluid structure interaction – elastohydrodynamic (EHD) model that includes the modeling of these frictional forces. After detailing the implementation of the lateral gap model, this paper presents measurements from carefully conducted experiments which correlate with the simulated predictions of the influence of frictional forces on the performance of a reference EGP design under study.
Cheolwoong Park - One of the best experts on this subject based on the ideXlab platform.
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performance and exhaust emission characteristics of a spark ignition engine using ethanol and ethanol reformed gas
2010Co-Authors: Cheolwoong Park, Young Choi, Changgi Kim, Gihun Lim, Yasuo MoriyoshiAbstract:Abstract Since ethanol is a renewable source of energy and has lower carbon dioxide (CO2) emissions than gasoline, ethanol produced from biomass is expected to be used more frequently as an alternative Fuel. It is recognized that for spark ignition (SI) engines, ethanol has the advantages of high octane and high combustion speed and the disadvantage of ignition difficulties at low temperatures. An additional disadvantage is that ethanol may cause extra wear and corrosion of electric Fuel Pumps. On-board hydrogen production out of ethanol is an alternative plan. Ethanol has been used in Brazil as a passenger vehicle Fuel since 1979, and more than six million vehicles on US highways are flexible Fuel vehicles (FFVs). These vehicles can operate on E85 – a blend of 85% ethanol and 15% gasoline. This paper investigates the influence of ethanol Fuel on SI engine performance, thermal efficiency and emissions. The combustion characteristics of hydrogen enriched gaseous Fuel made from ethanol are also examined. Ethanol has excellent anti-knock qualities due to its high octane number and a high latent heat of evaporation, which makes the temperature of the intake manifold lower. In addition to the effect of latent heat of evaporation, the difference in combustion products compared with gasoline further decreases combustion temperature, thereby reducing cooling heat loss. Reductions in CO2, nitrogen oxide (NOx), and total hydrocarbons (THC) combustion products for ethanol vs. gasoline are described.
A Baptista - One of the best experts on this subject based on the ideXlab platform.
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increasing the lifespan of high pressure die cast molds subjected to severe wear
2017Co-Authors: V Nunes, F J G Silva, M F Andrade, R J D Alexandre, A BaptistaAbstract:Abstract Regardless the increasingly incorporation of composite materials on vehicle components, high pressure die casting still remains one of the most useful manufacturing techniques to obtain automotive parts with a complex shape in a cost effective way. It is well known that automotive industry requires high production cadence as well as high products quality. Thus, systematic approaches are permanently being done leading to optimize all the production and management aspects. The aluminum alloys commonly used in automotive parts such as Fuel Pumps bodies, throttle bodies, EGR valves, support brackets and so on usually contain Silicon which presents high abrasively. The aluminum flow at high temperature and high speed into the mold induces severe wear, sometimes due to a combination of abrasion and erosion effects. In this study, two molds with typical severe wear problems were selected and the wear mechanisms involved were deeply studied. After that, a careful selection of the best coating for this purpose was done and some of the most critical parts of the mold were coated in order to test possible effective advantages of the coating application, analyzing the wear resistance behavior and wear mechanisms involved. In parallel, tribological tests were also carried out in order to study if a correlation between laboratory and industrial tests can be drawn. Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy were intensively used to characterize the coatings and the wear mechanisms observed. Laboratory tribological tests have involved ball scattering and block-on-ring tests, trying to impose low and medium loads on the contact, respectively. Promising results were obtained allowing conclude that certain coatings present a better behavior than other ones in this field of application.
Nicholas T. Powles - One of the best experts on this subject based on the ideXlab platform.
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Prediction models for density and viscosity of biodiesel and their effects on Fuel supply system in CI engines
2010Co-Authors: Belachew Tesfa, Rakesh Mishra, Fengshou Gu, Nicholas T. PowlesAbstract:Biodiesel is a promising non-toxic and biodegradable alternative Fuel used in the transport sector. Nevertheless, the higher viscosity and density of biodiesel poses some acute problems when it is used it in unmodified engine. Taking this into consideration, this study has been focused towards two objectives. The first objective is to identify the effect of temperature on density and viscosity for a variety of biodiesels and also to develop a correlation between density and viscosity for these biodiesels. The second objective is to investigate and quantify the effects of density and viscosity of the biodiesels and their blends on various components of the engine Fuel supply system such as Fuel pump, Fuel filters and Fuel injector. To achieve first objective density and viscosity of rapeseed oil biodiesel, corn oil biodiesel and waste oil biodiesel blends (0B, 5B, 10B, 20B, 50B, 75B, and 100B) were tested at different temperatures using EN ISO 3675:1998 and EN ISO 3104:1996 standards. For both density and viscosity new correlations were developed and compared with published literature. A new correlation between biodiesel density and biodiesel viscosity was also developed. The second objective was achieved by using analytical models showing the effects of density and viscosity on the performance of Fuel supply system. These effects were quantified over a wide range of engine operating conditions. It can be seen that the higher density and viscosity of biodiesel have a significant impact on the performance of Fuel Pumps and Fuel filters as well as on air-Fuel mixing behaviour of compression ignition (CI) engine.
