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Viewing 91 to 120 of 42294
2011-08-30
Journal Article
2011-01-2029
Atsushi Tanaka, Hiroki Shimada, Naoki Hiraiwa, Tsuyoshi Arai, Hideki Asano, Yasuhiro Nishikawa
The need to improve fuel consumption by saving the weights of automobile parts is growing from the viewpoint of global warming mitigation. In the case of a throttle body for controlling the air flow volume into an engine, it is important to achieve a high dimensional accuracy of the valve-bore gap in the state of closed valve. In fact, most throttle bodies are made of precision-machined metal. Therefore, resin throttle bodies are drawing attention as a lightweight alternate. However, in comparison with metal throttle bodies, resin throttle bodies have two potential disadvantages that should be solved prior to productization. The first one is greater air leakage in the state of closed valve, and the second one is smaller heat conduction for unfreezing the valve in a frigid climate. We have developed an electronic resin throttle body that has overcome the above-mentioned disadvantages.
2011-08-30
Technical Paper
2011-01-2025
David A. Blank
This study examines the novel use of a strong presence of radical ignition (RI) species to augment flame front propagation in a two-stroke spark ignition (SI) engine. Periphery mounted secondary chambers enable the generation of these RI species in one cycle for use in the next cycle. These chambers are outfitted to enable fuel-insertion and rapid heat addition. The new technology examined in the study employs the chemistry of homogeneous combustion radical ignition (HCRI) for the RI species enhancement of pre-mixed charge (PC) SI. The aim is to see if this chemistry can increase the lean burn threshold of this 2-stroke engine with natural gas (NG). The analysis uses experimental data together with a full chemical-kinetics simulation formulation that also accounts for thermo-chemical and hydro-dynamic exchanges that are both between the chambers and with the environment. The mechanism for the chemical kinetics consists of 97 chemical reactions involving 33 species.
2011-08-30
Technical Paper
2011-01-2026
Takayuki Sugita
An existing 4 stroke-cycle gasoline engine has been partially modified without dynamically changing its mechanism for the purpose to utilize compressed air as an alternative energy source. The principle is to mechanically control the compressed air flow through the intake and exhaust valves every revolution of the crankshaft by modifying the camshaft cam's lobes, which changes the engine operation from 4 strokes to 2 strokes cycle mode. In the previous investigation the principle was verified with a current 50 cc motorcycle modified engine and the pressure behavior inside the cylinder of the compressed air engine was evaluated. It turned out that the back pressure, which is defined as the positive pressure left in the expansion chamber while the piston is moving back from the bottom dead center to the top dead center, has high influence on the performance of the compressed air reciprocating engine.
2011-08-30
Technical Paper
2011-01-2052
Rei Ishida, Tomohiro Nakayama, Makoto Kaneko, Koji Morikawa
This paper details the air-fuel mixing process in a gasoline direct injection (DI) engine. Laser measurement techniques such as particle image velocimetry (PIV) and laser induced fluorescence (LIF) were employed on the optical engine with a transparent cylinder to analyze the in-cylinder flow and fuel vapor concentration. In addition, firing tests were conducted using an actual engine. Test results showed that the multi-stage injection is effective for air-fuel mixing and improvement of combustion stability.
2011-08-30
Journal Article
2011-01-2050
Takayuki Fuyuto, Takafumi Matsumoto, Yoshiaki Hattori, Ko Kugimoto, Taketoshi Fujikawa, Kazuhiro Akihama, Hisaki Ito
Over the last few decades, in-cylinder visualization using optically accessible engines has been an important tool in the detailed analysis of the in-cylinder phenomena of internal combustion engines. However, most current optically accessible engines are recognized as being limited in terms of their speed and load, because of the fragility of certain components such as the elongated pistons and transparent windows. To overcome these speed and load limits, we developed a new generation of optically accessible engines which extends the operating range up to speeds of 6000 rpm for the SI engine version, and up to in-cylinder pressures of 20 MPa for the CI engine version. The main reason for the speed limitation is the vibration caused by the inertia force arising from the heavy elongated piston, which increases with the square of the engine speed.
2011-08-30
Technical Paper
2011-01-2047
Hidenori Kosaka, Takuma Arai
In order to investigate the combustion phenomena in a combustion chamber of the diesel engine at transient operations, the simultaneous measurements of temperatures of flame and wall surface in a combustion chamber were conducted. The new technique for simultaneous measurements of flame temperature and wall surface was developed. Laser-Induced phosphorescence was used for the measurement of wall surface temperature which was coupled with the flame temperature measurement by a two-color pyrometry. The NOx and soot emissions were also measured simultaneously in transient operations. The relation between the temporal changes of emissions and temperatures of flame and surface wall are discussed. The results show that the temporal change of NOx emission during transient operation is similar to that of the average gas temperature in a chamber. On the other hand, the temporal change of soot emission is similar to neither that of flame temperature nor that of average gas temperature.
2011-08-30
Journal Article
2011-01-2051
Teruo Yamaguchi, Katsufumi Kondo, Hiroki Nishigai, Satoshi Takano, Tetsuya Aizawa
In order for better understanding of soot formation and oxidation processes in diesel spray flame, the morphology, microstructure and sizes of soot particles directly sampled in a transient spray flame were analyzed via high-resolution transmission electron microscopy (HRTEM). The soot distribution in the spray flame was simultaneously observed by high-speed shadowgraphy. The transient spray combustion was achieved in a constant volume combustion chamber under a high pressure and high temperature condition (940 K, 2.5 MPa). The soot samples were taken at different axial locations in the spray flame, 40 - 90 mm from the injector nozzle, using an intrusive soot sampler. Pressure histories, heat release rates and laser shadowgraphs of spray combustion were compared between the cases with and without the soot sampler in order to check the intrusion effect of soot sampler on combustion.
2011-08-30
Technical Paper
2011-01-2045
Koshiro Kimura, Sachio Mori, Masato Kawauchi, Rio Shimizu
A new method to measure in-cylinder flame propagation and mixture distribution has been developed. The distribution is derived from analyzing the temporal history of flame spectra of CH* and C2*, which are detected by a spark plug type sensor with multi-optical fibers. The validity of this method was confirmed by verifying that the measurement results corresponded with the results of high speed flame visualization and laser induced fluorescence (LIF) measurement. This method was also applied to analysis of cyclic combustion fluctuation on start-up in a direct injection spark ignition (DISI) engine, and its applicability was confirmed.
2011-08-30
Technical Paper
2011-01-2049
Julian T. Kashdan, Gilles Bruneaux
Non-intrusive, crank-angle resolved measurements of piston temperature have been performed in a single-cylinder direct-injection (DI) Diesel engine operating under highly-dilute low-temperature combustion (LTC) conditions. The laser-induced phosphorescence (LIP) technique exploits the temperature-dependent characteristics of rare-earth or transition metal doped ceramic phosphors. This paper describes the calibration procedure and subsequent application of the technique to measure piston surface temperature in a single-cylinder, optically-accessible Diesel engine for various parametric variations including fueling rate and injector nozzle characteristics. In addition, measurements of the nozzle tip temperature of a Diesel injector are also reported. Furthermore, a fiber-optic solution has been developed which enables piston surface temperature measurements to be performed in standard metal (i.e. non-optical) single-cylinder and multi-cylinder engines.
2011-08-30
Technical Paper
2011-01-2002
Masakuni Oikawa, Yusuke Ogasawara, Yoshikazu Kondo, Kanan Sekine, Kaname Naganuma, Yasuo Takagi, Yoshio Sato
A new ignition-combustion concept named PCC (Plume Ignition Combustion Concept), which ignite rich mixture plume in the middle of injection period or right after injection of hydrogen is completed, is proposed by the authors in order to reduce NOx emissions in high engine load conditions with minimizing trade-offs on thermal efficiency. In this study fundamental requirements of hydrogen jet to optimize PCC are investigated by using single and multi-hole nozzle with a combination of high speed laser shadowgraphy to visualize propagating flame. As a result, it was infered that igniting the mixture plume in the middle of injection period with minimizing jet penetration to chamber wall is effective reducing NOx formation even further.
2011-08-30
Journal Article
2011-01-2001
Thomas Wallner, Nicholas S. Matthias, Riccardo Scarcelli
Energy security and climate change are two of the main drivers for development of sustainable and renewable transportation solutions. Entities around the globe have been working on strategic plans to reduce energy consumption and curb greenhouse gas emissions. In this context hydrogen is frequently mentioned as the fuel and energy carrier of the future. The U.S. Department of Energy's (DOE's) FreedomCAR and Vehicle Technologies (FCVT) Program has identified hydrogen-powered internal combustion engine (ICE) vehicles as an important mid-term technology on the path to a large-scale hydrogen economy. DOE has set challenging goals for hydrogen internal combustion engines including 45% peak brake thermal efficiency (BTE). This paper summarizes recent research engine test results employing hydrogen direct injection with different injection strategies.
2011-08-30
Technical Paper
2011-01-2000
Jesper Ahrenfeldt, Ulrik Birk Henriksen, Torben Kvist
Experimental investigations have been conducted with two identical small scale SI gas engines gen-sets operating on biomass producer gas from thermal gasification of wood. The engines where operated with two different compression ratios, one with the original compression ratio for natural gas operation 9.5:1, and the second with a compression ratio of 18.5:1. It was shown that high compression ratio SI engine operation was possible when operating on biomass producer gas from a TwoStage gasifier. The results showed an increase in the electrical efficiency from 31% to 35% when the compression ratio was increased. The influence of ignition timing on emissions was investigated during high compression ratio operation. It was shown that for λ=1.4 the NOx emission decreases by almost a factor 3, when the timing is retarded from 13° to 7° before top dead center.
2011-08-30
Technical Paper
2011-01-1999
Yukihide Nagano, Tomohiro Takeo, Keiichiro Tomari, Akihiro Hayakawa, Shoichi Kobayashi, Toshiaki Kitagawa
Combustion properties of hydrogen with N₂ dilution were investigated. The laminar and turbulent burning velocities were examined for outwardly propagating stoichiometric H₂/O₂/N₂ flames varying the amount of diluent N₂. The unstretched laminar burning velocity, ul decreased with the increase in the amount of N₂. Markstein number, Ma, the sensitivity of the flame to the stretch due to the thermo-diffusive effects decreased with the increase in the amount of N₂.
2011-08-30
Technical Paper
2011-01-1998
Vilmar AEsoy, Per Magne Einang, Dag Stenersen, Erik Hennie, Ingebrigt Valberg
The maritime transportation sector is facing new international restrictions on exhaust emissions. NOx and SOx emissions from traditional marine fuels are a major challenge, which make natural gas a promising new clean alternative. Since the late 1980s, new concepts for medium-speed natural gas-fuelled engines have been developed, primarily for stationary power generation. This technology is currently entering the mobile sector, where Spark Ignition engines, Dual-Fuel engines and High Pressure Gas engines offer advantages such as high efficiency, low emissions and fuel flexibility. The availability of liquefied natural gas (LNG) is increasing, not least via small-scale distribution systems. In Norway, 23 coastal traffic vessels operate on LNG supplied by a distribution system that also supplies city bus fleets. This paper discusses the development of natural gas engines and fuel system technology, and describes experiences from LNG-fuelled ships in operation in Norway.
2011-08-30
Technical Paper
2011-01-1996
Ryo Michikawauchi, Shiro Tanno, Yasushi Ito, Mutsumi Kanda, Masato Kawauchi
This research aimed to identify how combustion characteristics are affected by the addition of hydrogen to methane, which is the main components of natural gas, and to study a combustion method that takes advantage of the properties of the blended fuel. It was found that adding hydrogen did not achieve a thermal efficiency improvement effect under stoichiometric conditions because cooling loss increased. The same result was obtained under EGR stoichiometric conditions. In contrast, under lean burn conditions, higher thermal efficiency and lower NOx than with methane combustion was achieved by utilizing the wide flammability range of hydrogen to expand the lean limit. Although NOx can be decreased easily by the addition of large quantities of hydrogen, the substantially lower energy density of the fuel causes a substantial reduction in cruising range. Consequently, this research improved the combustion of a CNG engine by increasing the tumble ratio to 1.8.
2011-08-30
Technical Paper
2011-01-1997
Marco Turcios, Carl Ollivier-Gooch, Jim Huang
The quenching of premixed laminar flames at various constant pressures was studied through numerical simulation, with the Trajectory Generated Lower Dimensional Manifold (TGLDM) method used to employ detailed chemical mechanisms for stoichiometric methane and heptane flames. The method was validated at lower pressures and wall temperatures. The laminar flame speed predicted by the TGLDM method agrees reasonably well with experimental data reported in the literature. The peak heat flux at quenching was found to be under-predicted by 30-40% of the most current experimental data. The quench distance was calculated for pressures of 1, 2, 20 and 40 bar, with wall temperatures of 300 and 600 K and fresh gas temperature of 300 K. The quench distance was found to decrease with increasing pressure in a manner similar to previous studies. The value of quench distance for heptane was found to be smaller than that of methane by a factor of ~30% over all pressures.
2011-08-30
Technical Paper
2011-01-1995
Jerome Obiols, Dominique Soleri, Nathalie Dioc, Marc Moreau
The use of CNG in modern spark ignition turbocharged engine offers many advantages such as high knocking resistance, low CO₂ emissions and high specific power outputs. On the other hand, compared to gasoline, the volumetric efficiency is significantly decreased when CNG is port-injected due to its low energy density. In order to address this issue, recent studies have successfully highlighted the advantages on port-injection engines of the CIGAL™ concept (Concomitant Injection of Gas And Liquid fuels) from IFP Energies Nouvelles. However, the combination of port-injection of CNG with direct injection of gasoline remains unexplored. This paper investigates this novel injection concept on the four-cylinder 1.6L turbocharged GDI engine with inlet variable valve timing resulting from the cooperation between PSA Peugeot-Citroen and the BMW Group.
2011-08-30
Technical Paper
2011-01-2024
Takamitsu Okamoto, Hiroshi Kawamura, Keisuke Tsukamoto, Masakatsu Nagai, Takahiro Uchida, Heiji Maruyama
Achieving the speed and performance of a true supercar was merely the starting point of this development. In addition, the development also focused on achieving emotive performance attributes to enhance driver appeal. For this the engine was developed to assist a vehicle handling provides unsurpassed response, the creating a feeling of infinite acceleration potential, response is instantaneous and based on close understanding of driver's reactions and Awe inspiring sound is providing. It meets the latest emission standard Euro V and achieves good fuel consumption with a wide range stoechiometric air fuel ratio, till speeds up to 240km/h.
2011-08-30
Journal Article
2011-01-2023
William P. Attard, Hugh Blaxill
Turbulent Jet Ignition is an advanced spark initiated pre-chamber combustion system for otherwise standard spark ignition engines found in current passenger vehicles. This next generation pre-chamber design simply replaces the spark plug in a conventional spark ignition engine. Turbulent Jet Ignition enables very fast burn rates due to the ignition system producing multiple, widely distributed ignition sites, which consume the main charge rapidly. This high energy ignition results from the partially combusted (reacting) pre-chamber products initiating combustion in the main chamber. The distributed ignition sites enable relatively small flame travel distances enabling short combustion durations and high burn rates. Multiple benefits include extending the knock limit and initiating combustion in very dilute mixtures (excess air and/or EGR), with dilution levels being comparable to other low temperature combustion technologies (HCCI), without the complex control drawbacks.
2011-08-30
Technical Paper
2011-01-2022
Mehrzad Kaiadi, Per Tunestal, Bengt Johansson
Abstract Stoichiometric operation of Spark Ignited (SI) Heavy Duty Natural Gas (HDNG) engines with a three way catalyst results in very low emissions however they suffer from bad gas-exchange efficiency due to use of throttle which results in high throttling losses. Variable Geometry Turbine (VGT) is a good practice to reduce throttling losses in a certain operating region of the engine. VTG technology is extensively used in diesel engines; it is very much ignored in gasoline engines however it is possible and advantageous to be used on HDNG engine due to their relatively low exhaust gas temperature. Exhaust gas temperatures in HDNG engines are low enough (lower than 760 degree Celsius) and tolerable for VGT material. Traditionally HDNG are equipped with a turbocharger with waste-gate but it is easy and simple to replace the by-pass turbocharger with a well-matched VGT.
2011-08-30
Journal Article
2011-01-2021
Tomomi Yamada, Hiroyuki Haga, Isao Matsumoto, Terutoshi Tomoda
In this study, we combined a diesel engine with the Toyota Hybrid System (THS). Utilizing the functions of the THS, reducing engine friction, lowering the compression ratio, and adopting a low pressure loop exhaust gas recirculation system (LPL-EGR) were examined to achieve both low fuel consumption and low nitrogen oxides (NOx) emissions over a wide operating range. After applying this system to a test vehicle it was verified that the fuel economy greatly surpassed that of a conventional diesel engine vehicle and that NOx emissions could be reduced below the value specified in the Euro 6 regulations without DeNOx catalysts.
2011-08-30
Technical Paper
2011-01-2005
Kimitaka Yamane, Mai Nogami, Yukio Umemura, Masakuni Oikawa, Yoshio Sato, Yuichi Goto
Key requirements of engines for vehicles are large output power and high efficiency, low emission as well as small size and light weight. Hydrogen combustion engines with direct injection have the characteristics to meet these factors. Tokyo City University, former Musashi Institute of Technology, has studied hydrogen fueled engines with direct injection since 1971. The key technology in the development of hydrogen fueled engines is the hydrogen injector for direct injection with the features such as high injection rate, high response and no hydrogen gas leakage from the needle valve of the hydrogen injector. A common-rail type system to actuate the needle valves of the high pressure hydrogen injectors was intentionally applied to fulfill good performances such as large injection rate, high response and no hydrogen gas leakage.
2011-08-30
Technical Paper
2011-01-2004
P. Huyskens, S. Van Oost, P. J. Goemaere, K. Bertels, M. Pecqueur
The chicken or the egg dilemma is an often used metaphor to explain the problem where car manufacturers are not eager to produce hydrogen cars since there are no hydrogen fueling stations. Petrochemical companies on the other side, do not want to invest in hydrogen fueling stations for there are no cars to fuel. Many proposals have been made to overcome this predicament, for example starting the implementation of the hydrogen economy with early markets such as public busses that run on hydrogen, because they can use a centralized fueling infrastructure and thereby reduce initial costs. However, another way to address this stalemate is by avoiding the dependency on hydrogen fueling infrastructure. This can be achieved by using flex-fuel vehicles that can run on hydrogen as well as on gasoline and/or compressed natural gas.
2011-08-30
Journal Article
2011-01-2003
Mithun Kanti Roy, Nobuyuki Kawahara, Eiji Tomita, Takashi Fujitani
Hydrogen spark-ignition (SI) engines based on direct-injection (DI) promise significant advantages in terms of thermal efficiency and power output, as well as a means of overcoming problems related to knocking, backfiring, and pre-ignition. In a DI hydrogen engine, the fuel/air mixture is formed by injecting a jet of hydrogen into the air inside the combustion chamber. An Ar-ion laser beam was used as a light source to visualize the hydrogen jet in a constant-volume chamber. This allowed us to study the structure of the jet in addition to other physical processes resulting from hydrogen gas injection. Combustion experiments were conducted in a single-cylinder SI optical research engine equipped with a DI system to detect the early kernel growth assisted by the spark, as well as flame propagation. Various equivalence ratios and fuel injection timings were analyzed to identify the effects on combustion.
2011-08-30
Technical Paper
2011-01-1989
Mitsuaki Ohtomo, Kazuaki Nishikawa, Tetsunori Suzuoki, Hiroshi Miyagawa, Makoto Koike
Furans such as 2-Methylfuran (2-MF) and 2,5-Dimethylfuran (DMF) can be produced from biomass sugars and offer superior properties for use in SI engines. This paper describes the study of the auto-ignition characteristics of furans and other biofuels using a rapid compression machine. Blending with PRF90 and RG, the auto-ignition suppression of 2-MF was almost equal to that of ethanol and larger than toluene, although the auto-ignition delay of pure 2-MF was shorter than that of ethanol and toluene. This was because 2-MF suppresses the cool flame reaction. Knock evaluation using a single-cylinder research engine also indicated that the addition of 2-MF improved the anti-knock properties as well as ethanol.
2011-08-30
Journal Article
2011-01-1990
T. Niass, A. A. Amer, W. Xu, S. R. Vogel, K. Krebber-Hortmann, P. Adomeit, A. Brassat
Blending gasoline with oxygenates like ethanol, MTBE or ETBE has a proven potential to increase the thermodynamic efficiency by enhancing knock resistance. The present research focuses on assessing the capability of a 2- and tert-butanol mixture as a possible alternative to state-of-the-art oxygenates. The butanol mixture was blended into a non-oxygenated reference gasoline with a research octane number (RON) of 97. The butanol blending ratios were 15% and 30% by mass. Both the thermodynamic potential and the impact on emissions were investigated. Tests are performed on a highly boosted single-cylinder gasoline engine with high load capability and a direct injecting fuel system using a solenoid-actuated multi-hole injector. The engine is equipped with both intake and exhaust cam phasers. The engine has been chosen for the fuel investigation, as it represents the SI technology with a strongly increasing market share.
2011-08-30
Technical Paper
2011-01-1992
Leonid Tartakovsky, V. Baibikov, M. Gutman, A. Mosyak, M. Veinblat
The goal of the present work was to analyze the performance of a spark ignition engine fueled by ethanol steam reforming products. The highest reformer-ICE system efficiency and the lowest CO emissions were achieved with the ethanol steam reforming products obtained at reaction temperature of 1000K and water/ethanol ratio of 1.8. Fueling the SI engine with reformate gas made it possible to achieve the reformer-ICE system efficiency of 40% for the engine fed by SRE products compared with 34% for gasoline and 36% for ethanol. CO emissions were reduced by 3.5 and 10 times compared with ethanol and gasoline, respectively. NO emissions were decreased by about 4 times compared with the gasoline-fed engine.
2011-08-30
Journal Article
2011-01-1991
Matthias Thewes, Martin Muther, Adrien Brassat, Stefan Pischinger, Andreas Sehr
In this study the fuel influence of several bio-fuel candidates on homogeneous engine combustion systems with direct injection is investigated. The results reveal Ethanol and 2-Butanol as the two most knock-resistant fuels. Hence these two fuels enable the highest efficiency improvements versus RON95 fuel ranging from 3.6% - 12.7% for Ethanol as a result of a compression ratio increase of 5 units. Tetrahydro-2-methylfuran has a worse knock resistance and a decreased thermal efficiency due to the required reduction in compression ratio by 1.5 units. The enleanment capability is similar among all fuels thus they pose no improvements for homogeneous lean burn combustion systems despite a significant reduction in NOX emissions for the alcohol fuels as a consequence of lower combustion temperatures.
2011-08-30
Technical Paper
2011-01-1994
Mas Fawzi Mohd Ali, Yoshiyuki Kodoguchi, Yusuke Oka, Tomoshi Kaida
Lean combustion is a useful mean to improve performance of a CNG engine. However, conventional premixed fuel injection method limits the lean combustible range. Lean combustion for CNG has problems such as misfire and THC emission. This study proposes the gas-jet ignition method to extend lean combustible limit of CNG engines. Results show that CNG engine can be operated at equivalence ratio ranges from 0.3 and 0.8 by applying two-stage injection combined with gas-jet ignition. First-injection timing is one of important parameter that affects THC emissions. Analyses of in-cylinder pressure histories and CFD calculation explain that combustion stability and THC emission are affected by fuel distribution. The distribution is controlled by the first and second injection timing. The second injection achieves good ignitability. The THC emission is caused by over-lean mixture in the cylinder in the case of early timing of first injection.
2011-09-13
Technical Paper
2011-01-2285
Lisa Larsson, Lennart Löfdahl, Erik Dahl, Torbjörn Wiklund
This investigation is a continuing analysis of the cooling performance and aerodynamic properties of a rear-mounted cooling module on a semi-generic commercial vehicle, which was carried out by Larsson, Löfdahl and Wiklund. In the previous study two designs of the cooling package installation were positioned behind the rear wheelhouse and the results were compared to a front-mounted cooling module. The investigation was mainly focused on a critical cooling situation occurring at lower vehicle speeds for a local distribution vehicle. The conclusion from the study was that the cooling performance for one of the rear-mounted installation was favorable compared to the front-mounted cooling package. This was mainly due to the low vehicle speed, the high fan speed and to fewer obstacles around the cooling module resulting in a lower system restriction within the installation.
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