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Viewing 1 to 30 of 52
2005-05-11
Technical Paper
2005-01-2202
Mitsuharu Oguma, Hitoshi Shiotani, Shinichi Goto, Shinichi Suzuki
In this report, trace levels of harmful substances, such as formaldehyde, acetaldehyde, SO2, benzene and so on, emitted from a DME fueled direct injection (DI) compression ignition (CI) engine were measured using a Fourier Transform Infrared (FTIR) emission analyzer. Results showed that the NO portion of NOx emissions with DME exceeded diesel fuel operation levels. DME fueling caused greater amounts of water than with diesel fuel operation. DME fueling was also associated with higher formaldehyde emissions than with diesel fuel operation. However, using an oxidation catalyst, formaldehyde could be decreased to a negligible level.
2005-05-11
Technical Paper
2005-01-2194
Shinichi Goto, Mitsuharu Oguma, Shinichi Suzuki
Dimethyl ether (DME) has been attracting notable attention as a clean alternative fuel for diesel engines. The authors developed a medium duty DME truck, and investigated aspects of vehicle performance such as engine power, exhaust characteristics, fuel consumption, noise, in-vehicle systems, and so on. Results indicated that higher engine torque and power could be achieved with DME compared to diesel fuel operation of the base engine at any engine speed. Results also showed that emissions decreased dramatically, to 27% for NOx, 74% for HC, 95% for CO and 94% for PM (Particulate Matter) compared to maximum allowed Japanese 2003 emission regulations. The operating noise of the DME vehicle was slightly lower than the base vehicle with diesel fuel, because the combustion noise with DME was decreased compared to with diesel fuel operation. The DME vehicle was given a public license plate in October 2004, after which running test continued on public roads and on a test course.
2010-04-12
Technical Paper
2010-01-1117
Taku Tsujimura, Shinichi Goto
The tasks to improve diesel emissions and fuel consumption must be accomplished with urgency. However, due to the trade-off relationship between NOx emissions, soot emissions and fuel consumption, clean diesel combustion should be achieved by both innovative combustion and fuel technologies. The objective of this study is to extend the clean diesel combustion operating range (Engine-out emission: NOx ≺ 0.2 g/kWh, Soot ≺ 0.02 g/kWh). In this study, performance of a single-cylinder test engine equipped with a hydraulic valve actuation system and an ultra-high pressure fuel injection system was investigated. Also evaluated, were the effects of fuel properties such as auto-ignitability, volatility and aromatic hydrocarbon components, on combustion performance. The results show that applying a high EGR (Exhaust gas recirculation) rate can significantly reduce NOx emission with an increase in soot emission.
1997-02-24
Technical Paper
970354
Ja Ye Koo, Seung Tae Hong, Joseph S. Shakal, Shinichi Goto
The effects of upstream conditions, such as nozzle and entrance shapes, on external flow characteristics continue to challenge fuel injection modeling efforts, particularly in the case of high-pressure diesel sprays. In this research, flow details were investigated both experimentally and numerically in a fuel injector nozzle orifice using an integrated approach. Calculations using the SIMPLE algorithm were first performed for the scaled-up experimental nozzles with various length to diameter ratios (L/d). Measurements of internal flow velocities for these nozzles were made by laser Doppler velocimetry in order to verify the computational results. Mean and fluctuating velocities and discharge coefficients were obtained at various Reynolds numbers. The mean turbulence intensity and turbulent kinetic energy for a sharp inlet nozzle were generally higher than for a round inlet nozzle, except for the near-wall region beginning at about one nozzle diameter from the entrance.
1992-02-01
Technical Paper
920689
Hirohide Furutani, Shunichi Tsuge, Shinichi Goto
This paper deals with the process regarding how dehydrogenation of soot particles takes place. The measured carbon/hydrogen ratios plotted against mean-diameter of soots fall on a straight line passing through the origin. It is shown that in the course of soot particle growth CM ratio increases linearly with the particle diameter: D. This is an indication of the fact that the number of carbon grows in proportion to D3, whereas that of hydrogen is proportional to D2. It is there by concluded that hydrogen sit only on surface of soot particles.
1992-02-01
Technical Paper
920690
Shinichi Goto, Hirohide Furutani, Rafael D. Delic
The authors tried to use LP gas, mainly butane, as the main fuel of diesel engines to reduce soot and to maintain high thermal efficiency. LP gas was injected in the direction of the intake valve directly as a spray to prevent knocking and to preserve high charging efficiency. The newly developed electronic fuel injection provided accurate fuel control and injection timing. As a result, the dual-fuel operation produced high thermal efficiency almost identical to that of diesel engines. Soot in engine exhaust was almost negligible. Three quarters of maximum output was obtained with butane, and only small amount of gas oil for idling, in spite of an high compression ratio of 17 for gas engines. Increasing the proportion of gas oil resulted in maximum output from a diesel engine and almost no soot output.
1998-10-19
Technical Paper
982566
J. Shakal, H. Ishikawa, Shinichi Goto, D. Lee
In this study, a piezo disk was used to generate a cloud of n-decane fuel drops, which were mixed with air, then carried into a combustion chamber and ignited by a platinum wire. Microgravity data obtained at the Japan Microgravity Center (JAMIC) were compared to normal gravity data, all at 1Atm pressure and 20+/-1°C initial temperature. Under normal gravity the lean limit was found to be 7.6x106/mm3 (Φ = 1.0), and from this point the flame front speed steadily increased from 20cm/s up to a maximum flame front speed of 210cm/s at a fuel drop density of about 14x106/mm3 (Φ = 1.85). Microgravity data showed a much richer lean limit - about 14.5x106/mm3 (Φ = 1.9), and the flame front speed did not gradually rise to a peak value. Instead, the measurements indicated a peak value of about 250cm/s, with a steep increase followed by a gradual decrease at richer fuel air ratios. A cellular flame structure appeared, and the cell size decreased as the mixture density increased.
1998-10-19
Technical Paper
982615
Hitoshi Ishikawa, Joseph S. Shakal, Shinichi Goto, Daeyup Lee
The combustion mechanism of a fuel droplet cloud was studied by numerical simulation. We investigated how the flame front speed and combustion products changed depending on the equivalence ratio and initial temperature. Modeling was performed using the KIVA-III software package, a three dimensional analysis software used mainly for internal combustion engine applications. The computational domain was a horizontal 1x1x100 cell sector of a spherical combustion chamber and the fuel was n-decane. Results showed that when all the fuel droplets were assumed to have evaporated, the flame front speed increased from 28 cm/s to 152 cm/s as the equivalence ratio increased. The maximum flame front speed was reached at ϕ=1.1, beyond which it decreased (at richer overall equivalence ratios). With a constant equivalence ratio, the flame front speed decreased near the outside region, because the unburned gas was compressed by the expanding burned gas.
2007-01-23
Technical Paper
2007-01-0028
Taku Tsujimura, Shinichi Goto, Hideki Matsubara
In this study, diesel exhaust emission characteristics were investigated as GTL (Gas To Liquid) fuel was applied to a heavy-duty diesel truck which had been developed to match a Japanese new long-term exhaust emission regulation (NOx < 2.0 g/kWh, PM < 0.027 g/kWh). The results in this study show that although the test vehicle has advanced technologies (e.g. high pressure fuel injection, oxidation catalyst, and urea-SCR aftertreatment system, etc.) which are applied to reduce diesel emissions, the neat GTL fuel has a great advantage to reduce particulate matter emissions and poly aromatic hydrocarbons. And regarding nano-size PM emissions, nuclei mode particles emitted during idling are significantly decreased by using the GTL fuel.
2007-01-23
Technical Paper
2007-01-0032
Mitsuharu Oguma, Shinichi Goto
The performance of a medium duty DME truck was evaluated by field tests and engine bench tests. The DME vehicle was given a public license plate on October 2004, after which running tests were continued on public roads and a test course. The DME vehicle could run the whole distance, about 500 km, without refueling. The average diesel equivalent fuel consumption of the fully loaded DME truck was 5.75 km/l, running at 80 km/h on public highways. Remedying several malfunctions that occurred in the power-train subsystems enhanced the vehicle performance and operation. The DME vehicle accumulated 13,000 km as of August, 2006 with no observed durability trouble of the fuel injection pump. Disassembly and inspection of the fuel injectors after 7,700 km operation revealed a few differences in the nozzle tip and the needle compared to diesel fuel operation. However, the injectors were used again after cleanup.
2007-01-23
Technical Paper
2007-01-0073
Hitoshi Shiotani, Shinichi Goto
Biodiesel fuel has attracted much attention as a carbon neutral fuel because it is made from vegetable oil. Especially in Southeast Asia, there are numerous biofuel resources, such as palm oil and coconut oil, and it is desirable to utilize these for CO2 reduction. In this paper, we evaluate the properties of biodiesel fuel and biodiesel blended diesel oil. The low temperature performance of palm oil methyl ester (PME) is poor and it affects low temperature performance, even if the PME blending rate is low. The oxidation stability is a very important property of biodiesel fuel because degraded biodiesel fuel produces organic acids and polymeric substances. PME contains mainly saturated fatty acids methyl esters, so the oxidation stability is better than other fats and oils. When containing antioxidants such as beta carotene, biodiesel's oxidation stability is improved.
2006-10-16
Technical Paper
2006-01-3303
Takehiro Tsuchiya, Hitoshi Shiotani, Shinichi Goto, Gen Sugiyama, Akira Maeda
The Agency of Natural Resources and Energy, Ministry of Economy, Trade and Industry has conducted conformity tests of diesel fuel containing Fatty Acid Methyl Ester (FAME) to amend diesel fuel standards in Japan. The objective of the tests is to examine appropriate specifications of diesel fuel containing FAME for automotive use for existing vehicles in the Japanese market. The conformity testing includes verification of fuel system component compatibility, tail pipe emissions, and characterization of the reliability and durability of the engine system, including the fuel injection system. In designing the conformity tests, the maximum FAME concentration was 5%. Most of the new standards are essentially equivalent to EN14214, but the total acid number (TAN) of specific acids, and oxidation stability of the new standards for diesel fuel containing FAME, are different from EN14214.
2006-11-13
Technical Paper
2006-32-0023
Hitoshi Shiotani, Shinichi Goto, Koichi Kinoshita, Danilo Nikolic
In this study, measurement methods of aldehydes and volatile organic compounds (VOCs) from off-road engine have been investigated. Also, their emission characteristics have been evaluated. By using high-performance liquid chromatograph (HPLC), aldehydes could be measured with small variation. Major aldehydes from off-road engine are formaldehyde and acetaldehyde. Total aldehydes emission is not necessarily low compared to THC emission. The emission characteristics of aldehydes are similar to that of CO, THC and PM. For VOCs sampling, sampling tube with absorbent was better than sampling bag because some kinds of VOCs tend to become absorbed on the sampling bag. Except for 1,3-butadiene, VOCs could be measured with small variation by using gas chromatography-mass spectrometer (GC-MS). Benzene, toluene and xylene were major species found in VOCs. The emission characteristics of VOCs were also similar to ones of CO, THC and PM.
2003-10-27
Technical Paper
2003-01-3193
Koichi Kinoshita, Mitsuharu Oguma, Shinichi Goto, Kouseki Sugiyama, Makihiko Mori, Tomoko Watanabe
Since dimethyl ether (DME) is a synthetic fuel, it is possible to make it from natural gas, coal and biomass. It is a low-emission, oxygenated fuel, which does not generate soot in the exhaust. Therefore, it has recently been identified as a possible replacement for diesel fuel. In Japan, the new short-term emissions regulations will be enforced beginning in 2003, and the long-term emissions regulations are scheduled to be enforced in 2005. In order to meet these more stringent emissions regulations, existing diesel engines would not be as widely used in the near future as they currently are. This will thus bring about a more widespread use of DME engines due to their low emissions potential. Moreover, when the modification of existing diesel engines into DME engines is available at a moderate cost, the wider use of DME engines can be expected. This study targeted development and application of DME engine technology for diesel engine retrofit, in a used diesel vehicle.
2003-10-27
Technical Paper
2003-01-3192
Mitsuharu Oguma, Shinichi Goto, Hidefumi Hatsuzawa, Mitsuru Konno, Zhili Chen, Tomoko Watanabe
To date, the DME combustion mechanism has been investigated by in-cylinder gas sampling, numerical calculations and observation of combustion radicals. It has been possible to quantify the emission intensities of in-cylinder combustion using a monochromator, and to observe the emitting species as images by using band-pass filters. However, the complete band images were not observed since the broadband (thermal) intensity may be stronger than band spectra intensities. Emission intensities of DME combustion radicals from a pre-mixed burner flame have been measured using a spectroscope and photomultiplier. Results were compared to other fuels, such as n-butane and methane, then, in this study, to better understand the combustion characteristics of DME, emission intensities near CH bands of an actual DI diesel engine fueled with DME were measured, and band spectra emitted from the engine were defined. Near TDC, emission intensities did not vary with wavelength.
2003-05-19
Technical Paper
2003-01-1948
Masahiro Fukumoto, Mitsuharu Oguma, Shinichi Goto
In this study, lubricity improvers were added to three different GTL fuels, which were then quantified with a High Frequency Reciprocating Rig (HFRR) and compared with ultra low sulphur diesel fuel (ULS). Furthermore, the lubricity of mixtures of a GTL blended with ULS was also investigated. Two kinds of compounds were tested as lubricity improvers: unsaturated fatty acids (UFA-type) and partial UFA esters of glycerin (Ester-type). All GTL fuels showed less sensitivity to a lubricity additive than ULS did, but the ULS mixture had better than expected lubricity. Thus it was concluded that blending of GTLs with ULS can be regarded as one practical measure to sufficiently improve lubricity. HFRR tests performed under the same viscosity suggested that fuel composition had an important effect on its sensitivity to an additive, as well as viscosity.
2003-05-19
Technical Paper
2003-01-1920
Kouseki SUGIYAMA, Masataka KAJIWARA, Masaaki IWAMA, Makihiko MORI, Mitsuharu OGUMA, Koichi KINOSHITA, Shinichi GOTO
Experiments were conducted to operate a direct injection (DI) diesel engine by using Liquefied Petroleum Gas (LPG) as a main fuel. Aliphatic Hydrocarbon (AH), cetane enhancing additive and lubricating additive were also added to the LPG so that smooth operation was achieved with a wide range of engine loads. Since the lubricity of LPG is lower than the diesel fuel therefore lubricating additive was employed to enhance the lubricity of LPG blended fuel. Furthermore, prototype LPG diesel truck was developed in this work, and the mileage reached about 70,000 km without any major failure. Prototype truck has good starting, good drive-off, acceleration and braking characteristics.
2003-10-27
Technical Paper
2003-01-3092
Kouseki Sugiyama, Makihiko Mori, Masataka Kajiwara, Masahiro Fukumoto, Shinichi Goto
In this research, a test apparatus (VPT-HFRR) for evaluating lubricity was manufactured at an arbitrary pressure according to the lubricity test method (HFRR) for diesel fuel. The lubricity of LPG blended fuel (LBF) for diesel engines was examined using VPT-HFRR., This was a value close to that of diesel fuel, and when a suitable lubricity had been maintained, it was checked. Prototype trucks were manufactured and their durability was examined. After a run of 70,000km or more, no serious trouble had occurred, and when LBF was maintained at a suitable lubricity, it was checked.
2004-03-08
Technical Paper
2004-01-0089
Hidefumi Hatsuzawa, Mitsuharu Oguma, Shinichi Goto, Tomoko Watanabe, Mitsuru Konno
For better understanding of the combustion characteristics in a direct injection dimethyl ether (DME) engine, the chemiluminescences of a burner flame and in-cylinder flame were analyzed using the spectroscopic method. The emission intensities of chemiluminescences were measured by a photomultiplier after passing through a monochrome-spectrometer. For the burner flame, line spectra were found nearby the wave length of 310 nm, 430 nm and 515 nm, arising from OH, CH and C2 radicals, respectively. For the in-cylinder flame, a strong continuous spectrum was found from 340 nm wave length to 550 nm. Line spectra were also detected nearby 310 nm, 395 nm and 430 nm, arising from OH, HCHO, and C2 radicals, respectively, partially overlapping with the continuous spectrum. Of these line spectra, 310 nm of OH radical did not overlapped with the continuous spectrum.
2004-03-08
Technical Paper
2004-01-0088
Mitsuharu Oguma, Shinichi Goto, Zhili Chen
In this study, advantages of GTL fueled DI diesel engine were observed, then, some cautionary areas, notably the aptitude for sealing materials, were investigated. Some advantages of using GTL as a diesel engine fuel include reduction of soot emission levels, power output and fuel consumption with GTL to conventional diesel fuel operation is equivalent, super-low sulfur content of GTL and its liquid state at normal temperature and pressure. However, there are some problems with putting GTL fuel on the market, such as lubricity, aptitude for sealing materials, high cetane index and high pour point. It is necessary to use additives to improve GTL's lubricity, and selecting the most appropriate type of lubricity improver is also important. The influence of GTL on the swelling properties of standard rubber materials seem basically the same, but it is necessary to notice on used rubbers.
2008-04-14
Technical Paper
2008-01-0062
Taku Tsujimura, Mitsuharu Oguma, Shinichi Goto
It has been clarified that diesel fuel properties have a great effect on the exhaust emissions and fuel consumption of a conventional diesel combustion regime. And as other diesel combustion regimes are applied in order to improve exhaust emissions and fuel consumption, it can be supposed that the fuel properties also have significant effects. The purpose of this study is to propose the optimum diesel fuel properties for a premixed compression ignition (PCI) combustion regime. In this paper, the effect of the auto-ignitability of diesel fuels on exhaust emissions and fuel consumption was evaluated using a heavy-duty single-cylinder test engine. In all experiments, fuels were injected using an electronically controlled, common-rail diesel fuel injector, and most experiments were conducted under high EGR conditions in order to reduce NOx emissions.
2004-06-08
Technical Paper
2004-01-1863
Mitsuharu Oguma, Shinichi Goto, Tomoko Watanabe
The engine performance and exhaust characteristics of the DME-powered diesel engine with an injection system developed for DME were investigated. The injection pump is an inline type that can inject double amount of DME fuel compared to the base injection pump because the calorific value of DME is about half lower than that of diesel fuel. The effect of injection timing on engine performances such as thermal efficiency, engine torque, and exhaust characteristics were investigated. Maximum torque and power with DME could be achieved the same or greater level compared to diesel fuel operation. Considering over all engine performances, the best dynamic injection timings without EGR were -3, -3, -6 and -9 deg. ATDC in 1120, 1680, 2240 and 2800 rpm engine speeds respectively in this experiment.
2004-06-08
Technical Paper
2004-01-1865
Kouseki Sugiyama, Masataka Kajiwara, Masahiro Fukumoto, Makihiko Mori, Shinichi Goto, Tomoko Watanabe
In this study, a MPT-HFRR (Multi-Pressure/Temperature High-Frequency Reciprocating Rig) was manufactured based on a diesel fuel lubricity test apparatus. The MPT-HFRR was designed to be used for conventional test methods as well as for liquefied gas fuel tests. Lubricity tests performed on a calibration standard sample under both atmospheric pressure and high pressure produced essentially constant values, so it was determined that this apparatus could be used for assessing the lubricity of fuel. Using this apparatus, the improvement of lubricity due to the addition of a DME (Dimethyl Ether) fuel additive was investigated. It was found that when 50ppm or more of a fatty acid lubricity improver was added, the wear scar diameter converged to 400μm or less, and a value close to the measured result for Diesel fuel was obtained. The lubricity obtained was considered to be generally satisfactory.
2003-05-19
Technical Paper
2003-01-1797
Mitsuharu Oguma, Shinichi Goto, Hidefumi Hatsuzawa, Mitsuru Konno, Zhili Chen, Tomoko Watanabe
To better understand the combustion characteristics of DME, emission intensities of DME combustion radicals from a pre-mixed burner flame were measured by a spectroscope and photomultiplier, Results were compared to other fuels, such as methane and butane. Large peaks in the band spectra from pre-mixed and diffusion DME flames were found near 310 nm, 430 nm, and 515 nm, arising from OH, CH and C2, respectively. The DME emission intensities decreased with increasing the equivalence ratio in this study. Notably, the relative decrease in the C2 band spectra peak was greater than that of the OH band. Comparing the pre-mixed DME and butane flames, the butane band spectra peaks were similar in shape, but much stronger than those for DME. However, it was remarkable that CH and C2 band spectra peaks decreased only slightly with increase in equivalence ratio compared to the DME case.
1999-10-25
Technical Paper
1999-01-3602
Shinichi Goto, Daeyup Lee, Yoshitaka Wakao, Hidekazu Honma, Makihiko Mori, Yukio Akasaka, Kohtaro Hashimoto, Masamitsu Motohashi, Mitsuru Konno
A feasibility study of an LPG DI diesel engine has been carried out to study the effectiveness of two selected cetane enhancing additives: Di-tertiary-butyl peroxide (DTBP) and 2-Ethylhexyl nitrate (EHN). When more than either 5 wt% DTBP or 3.5 wt% 2EHN was added to the base fuel (100 % butane), stable engine operation over a wide range of engine loads was possible (BMEPs of 0.03 to 0.60 MPa). The thermal efficiency of LPG fueled operation was found to be comparable to diesel fuel operation at DTBP levels over 5 wt%. Exhaust emissions measurements showed that NOx and smoke levels can be significantly reduced using the LPG+DTBP fuel blend compared to a light diesel fuel at the same experimental conditions. Correlations were derived for the measured ignition delay, BMEP, and either DTBP concentration or cetane number. When propane was added to a butane base fuel, the ignition delay became longer.
1999-03-01
Technical Paper
1999-01-0570
Daeyup Lee, Joseph Shakal1, Shinichi Goto, Hitoshi Ishikawa2, Hiroki Ueno, Naoya Harayama
Using an extended bottom view piston having a quartz window, flame propagation observation and flame contour analysis were carried out to investigate the combustion characteristics of a heavy-duty type LPG lean burn engine. The swirl ratio and piston cavity configuration were varied to investigate their effects on combustion and engine performance. Gradual reduction of NOx but increased hydrocarbon emissions were measured for leaner mixtures compared to the stoichiometric operation. High swirl apparently accelerated the initial flame kernel development, as evidenced by a shorter crank angle interval from the spark ignition to the maximum cylinder pressure. The ‘D’ type cavity, with an increased squish area located below the intake valve, was shown to have the shortest burn duration among the piston cavities tested. The experimental flame propagation observation procedure was shown to be useful for the study of the combustion process in engines.
1999-05-03
Technical Paper
1999-01-1513
Shinichi Goto, Daeyup Lee, Joseph Shakal, Naoya Harayama, Fumitaka Honjyo, Hiroki Ueno
Performance and emissions of an LPG lean burn engine for heavy duty vehicles were measured. The piston cavity, swirl ratio, propane - butane fuel ratio, and EGR were varied to investigate their effects on combustion, and thus engine performance. Three piston cavities were tested: a circular flat-bottomed cavity with sloped walls (called the “bathtub” cavity), a round bottomed cavity (called the “dog dish” cavity), and a special high-turbulence cavity (called the “nebula” cavity). Compared to the bathtub and dog dish cavities, the nebula type cavity showed the best performance in terms of cyclic variation and combustion duration. It was capable of maintaining leaner combustion, thus resulting in the lowest NOx emissions. High swirl improved combustion by achieving a high thermal efficiency and low NOx emissions. In general, as the propane composition increased, cyclic variation fell, NOx emissions increased, and thermal efficiency was improved.
2000-03-06
Technical Paper
2000-01-0331
Tadashi Tsurushima, Takeshi Miyamoto, Hisashi Akagawa, Yuzo Aoyagi, Je-Hyung Lee, Daeyup Lee, Shinichi Goto, Tomoyuki Wakisaka, Takuji Ishiyama, Hiroshi Kawanabe
To find more effective lean mixture preparation methods for smokeless and low NOx combustion, a numerical study of the effects of in-cylinder flow field before injection on mixture formation in a premixed compression ignition engine was conducted. Premixed compression ignition combustion is a very attractive method to reduce both NOx and soot emissions, but it still has some problems, such as high HC and CO emissions. In case of early direct injection, it is important to avoid wall wetting by spray impingement, which can cause higher HC and CO emissions. Since it is not easy to examine the effects of initial flow and injection parameters on mixture formation over the wide range by practical engine tests, a computer program named “GTT (Generalized Tank and Tube)” code was used to simulate the in-cylinder phenomena before autoignition.
1999-10-25
Technical Paper
1999-01-3510
Daeyup Lee, Shinichi Goto, Insu Kim, Masamitsu Motohashi
Band spectrum images for CH, OH and CHO were taken in a heavy duty type LPG lean-burn SI engine, to investigate the combustion process as it pertains to the pollutant formation process in the post flame region. Full spectra and band spectrum flame images were observed with a bottom view single cylinder research engine and two high speed cameras. NOx emissions were also measured for excess air ratios ranging from 1.0 to 1.6. A thermodynamic model, including the detailed chemical kinetic mechanism for LPG and NOx formation reactions, was developed to predict the major reaction species in the post flame region, and NOx emissions during the combustion process. The model qualitatively described the flame images for each band spectrum and could predict the measured NOx emissions very well.
1999-10-25
Technical Paper
1999-01-3481
Insu Kim, Daeyup Lee, Shinichi Goto
Flame propagation characteristics, in a heavy-duty type LPG lean burn SI engine, were investigated by simulation methodology, using the global one step and the ten step chemical kinetic reaction mechanisms, respectively. The swirl ratio and equivalence ratio were varied to investigate their effects on flame front speed. The effect of increased swirl intensity on flame speed was very minor at ranges of equivalence ratio of this study. Flame front shape, however, was affected by swirl intensity. Circular flame front formed for a higher swirl ratio, which is in a qualitative accordance with that of measurements. Comparison between calculation and measurements of flame propagation characteristics shows a good agreement for both the global one step and the ten step chemical kinetic model. This work concludes that the reduced chemical kinetic reactions, consisting of ten steps, is useful for flame propagation study in an LPG SI engine.
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