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Viewing 61 to 90 of 110594
2017-10-08
Technical Paper
2017-01-2234
David Vuilleumier, Magnus Sjöberg
Fundamental engine research is primarily conducted under steady state conditions, in order to better describe boundary conditions which influence the studied phenomena. However, light-duty automobiles are operated, and tested, under heavily transient conditions. This mismatch between studied conditions and in-use conditions is deemed acceptable due to the fundamental knowledge gained from steady-state experiments. Nonetheless, it may be of use to characterize the conditions encountered during transient operation and determine if the controlled phenomena are unduly influence by the differences between steady-state and transient operation, and further, whether transient behavior can be reasonably extrapolated from steady state behavior. This study investigates the effect of transient operation on Knock-Limited Combustion Phasing (KL-CA50) compared to steady-state operation.
2017-10-08
Technical Paper
2017-01-2199
Maria Cristina Cameretti, Vincenzo De Bellis, Luca Romagnuolo, Agostino Iorio, Luigi Maresca
Engine manufacturers are continually committed to find proper technical solutions to meet the more and more stringent CO2 emission targets fixed worldwide. Many strategies have been already developed, or are currently under study, to attain the above objectives. A tendency is however emerging towards more innovative combustion concepts, able to efficiently burn lean or highly diluted mixtures. To this aim, the enhancement of turbulence intensity inside the combustion chamber has a great importance, contributing to improve the burning rate, increase the thermal efficiency, and also reduce the cyclic variability. It is well-known that turbulence production inside the combustion chamber is mainly achieved during the intake stroke. Moreover, it is strongly affected by the intake duct geometry and orientation with respect to a plane perpendicular to the cylinder axis.
2017-10-08
Technical Paper
2017-01-2287
Aniseh Abdalla, Guoyang Wang, Jun Zhang, Shi-Jin Shuai
Emission control technologies are required to achieve stringent emission regulations such as Beijing 6 (equivalent to Europe 6). In order to meet Europe 6 emission regulation, diesel oxidation catalyst (DOC) upstream of catalyzed diesel particulate filter (CDPF) with supplementary fuel injection (hydrocarbon injection (HCI)) are used for the X7 diesel engine to control the particulate matter (PM) for a heavy-duty diesel engine. This study investigated soot loading and active regeneration process in a CDPF by using secondary fuel injection in order to enhance exothermal heat which is needed to raise the CDPF temperature. The injected fuel is burnt in a DOC where the injector is mounted in the tailpipe upstream of DOC.
2017-10-08
Technical Paper
2017-01-2182
Xikai Liu, Xingyu Liang, Yonge Wu, Yuesen Wang
According to the study of the soot emission in marine diesel, ,a new reduced mechanism for n-heptane was constructed to describe the combustion process in diesel engine by using sensitivity analysis.Furthermore,verifying the ignition delay time,the laminar flame speed,the flame propagation distance and species profiles in combustion process by using Chemkin Pro in different pressure(13.5atm and 42 atm),initial temperatures and equivalence ratio(0.5 and 1.0).Then,compare the simulated result with the experiment data and the simulated result by using LLNL(lawrence livermore national laboratory)detail mechanism and SKLE(state key laboratory of engine)mechanism.It is demonstrated that the reduced mechanism can not describe the ignition delay time in low temperature.And then,the reduced mechanism was adjusted and optimized to make it more close to the experiment data,and the reduced mechanism were able to predict ignition delay time,laminar flame speed,flame propagation distance and species profiles.The final reduced n-heptane mechanism are more compact compare with the current detailed mechanisms in literature.Thus,this reduced n-heptane mechanism can reduce the pressure of calculation and save the calculation time.
2017-10-08
Technical Paper
2017-01-2194
Mateusz Pucilowski, Mehdi Jangi, Sam Shamun, Martin Tuner, Xue-Song Bai
Experimental heavy-duty DICI methanol engine is studied under high compression ratio conditions (CR=27). The fuel is injected with common-rail injector close to the top-dead-center (TDC) position with three different injector pressures, leading to a spray formation causing a so called wall-wetting. Numerical simulations using RANS/LPT/WSR and PDF models are employed to investigate the local conditions of the injection and combustion process. The CFD results are compared with the pressure trace and emissions from the metal engine experiment. It is shown that the simulations captured the same trend of increased amount of unburned hydrocarbons at higher injection pressures. Moreover, the intake temperature adjustments were required to correctly capture the ignition delay time when WSR model was used, whereas with the PDF method such adjustments were not needed.
2017-10-08
Technical Paper
2017-01-2204
Hoon Lee, Kwangwoo Jeong, Sanghoon Yoo, Byungho Lee, Sejun Kim
Hyundai Motor Company recently developed a multi-way, electrical coolant valve for engine thermal management module. The main purposes of the system that replaces a mechanical thermostat are to boost fuel economy by accelerating warm-up and to enhance thermal efficiency by actively controlling engine operating temperature. The electrical valve controls the amount of coolant flow to components such as oil heat exchanger, heater core, and radiator, while providing separate cooling for engine block and head. The coolant flow is modulated by varying the valve angle actuated with an electric motor. The system operates under a thermal management strategy that consists of multiple phases including zero coolant flow mode, and for those phases that require coolant temperature control, a feedback algorithm is designed for the flow control.
2017-10-08
Technical Paper
2017-01-2210
Masayoshi Matsuda, Takeshi Yokomori, Norimasa Iida
The thermal efficiency of a spark­ignition (SI) engine must be improved to reduce both environmental load and fuel consumption. Although lean SI engine operation can strongly improve thermal efficiency relative to that of stoichiometric SI operation, the cycle-to-cycle variation (CCV) of combustion increases with the air dilution level. Combustion CCV is caused by CCVs of many factors, such as EGR, spark energy, air-fuel ratio, and in-cylinder flow structure related to engine speed. This study focuses on flow structures, especially the influence of a tumble structure on flow fluctuation intensity near ignition timing. We measured the flow field at the vertical center cross section of an optically accessible high-tumble flow engine using time-resolved particle image velocimetry. There are many factors considered to be sources of CCV, we analyzed three factors: the intake jet distribution, distribution of vortex core position and trajectory of the fluid particle near the spark plug.
2017-10-08
Technical Paper
2017-01-2209
Christian Ibron, Mehdi Jangi, Tommaso Lucchini, Xue-Song Bai
Partially premixed combustion (PPC) can be applied to decrease emissions and increase fuel efficiency in direct injection, compression ignition (DICI) combustion engines. PPC is strongly influenced by how the fuel mixes with oxidizer, which for a given fuel is controlled mainly by (a) the injection, (b) the in-cylinder flow and (c) the geometry and dynamics of the engine. As injection timings can vary over a wide range in PPC combustion deeper knowledge of the in-cylinder flow over the whole compression stroke can improve our understanding of PPC combustion. In computational fluid dynamics (CFD) the in-cylinder flow is sometimes simplified and modeled as a solid body rotation at some time prior to injection in order to produce a realistic flow field at the moment of injection. In real engines the in-cylinder flow motion is governed by the intake manifold, the valve motion and the engine geometry.
2017-10-08
Technical Paper
2017-01-2213
Satoshi Hokimoto, Tatsuya Kuboyama, Yasuo Moriyoshi, Minoru Iida, Takahiro Watanabe
Reduction in the cycle-to-cycle variation (CCV) of combustion in internal combustion engines has been required because CCV affects fuel consumption, emissions and drivability. CCV becomes stronger at low load or lean / diluted burn conditions. Specifically, the factors that cause CCV of combustion are supposed to variations of in-cylinder flow, fuel distribution, temperature distribution, residual gas distribution and ignition energy in each cycle. However, it is impossible to measure and analyze minutely these factors in a production engine. In this study, CCV of the combustion and in-cylinder phenomena in the same cycle of PFI gasoline engine were investigated by using an optical single-cylinder engine. This optical engine can observe the whole combustion chamber by the quartz glass cylinder and pent-roof window. CCV of flow in the cylinder during continuous 45 firing cycles was measured by Time Resolved Particle Image Velocimetry (TR-PIV) technique.
2017-10-08
Technical Paper
2017-01-2212
Jun Peng, Mingyang Ma, Wang Weizhi, Fu-qiang Bai, Qing Du, F Zhang
High-pressure common rail(HPCR)fuel injection system is the most widely used fuel system for diesel engines due to the fact that it can provide constant injection pressure and precise injection strategy. However, when multiple injection strategy is used, the pressure wave caused by the opening and closing of the needle valve will affect the subsequent injection and can not be neglected. In this paper, the influence of pressure wave on the second injection pressure, injection rate and fuel-injection quantity is carried out on a common rail fuel injection test rig under two-stage injection conditions. The results show that the pressure wave varies in terms of various rail pressure, environmental back pressure and injection intervals, resulting in a 10% fluctuation. As a consequence, the injection quantity will be changed. In detail, increasing injection intervals leads to an enhancement of injection pressure, injection pressure fluctuations and the decrease of injection quantity.
2017-10-08
Technical Paper
2017-01-2215
Mingming Ma
Lubricating oil system models of aero-engine whole process are established by applying ANN based on a large number of flight test data. Model results are in good agreement with flight test results, which shows the feasibility and effectiveness of the presented modeling method. The results of model are applied to the test condition monitoring of the aero-engine lubricating oil system, thus the real-time tendency monitoring of lubricating oil parameters is realized and application. In addition, a method to determine the main influence parameters of aero-engine lubricating oil parameters is developed by using the presented modeling method.
2017-10-08
Technical Paper
2017-01-2214
Kwee-Yan Teh, Penghui Ge, Yusheng Wang, David Hung
The large-scale rotating flow structure in an engine cylinder exhibits features that can be described in generic terms of tumble and swirl. The structural details, nevertheless, vary from cycle to cycle due to fluctuating initial and boundary conditions of the flow. Typical analysis of the flow field cyclic variability — by simple root-mean-square, or additional spatial or temporal filtering, or proper orthogonal decomposition — is based on pointwise deviation of the instantaneous velocity from the ensemble mean. However, that analysis approach is not amenable to the evaluation of spatial variation of the flow structure, in position and orientation, within the flow field. To this end, other studies in the past focused instead on quantifying the variation of the vortex center for the dominant tumble or swirl pattern within the flow field.
2017-10-08
Technical Paper
2017-01-2232
Liming Cao, Ho Teng, Ruigang Miao, Xuwei Luo, Tingjun Hu, Xianlong Huang
Atkinson cycle realized with a late intake valve closing (LIVC) and Miller cycle achieved with an early intake valve closing (EIVC) have been recognized as effective approaches for improving the gasoline engine fuel economy. In both Atkinson and Miller cycles, the engine can be designed with a higher geometric compression ratio for increasing the expansion work and the effective compression ratio is governed by the intake valve close (IVC) timing for the knock control. Duration of the intake event and IVC timing affect not only the pumping loss during the gas exchange, but also have strong influences on the friction torques of the intake cams and the turbulence intensities for the in-cylinder charge motion. The latter governs duration of combustion and EGR tolerance, both of which have impacts on the engine thermal efficiency.
2017-10-08
Technical Paper
2017-01-2245
Xianlin Ouyang, Ho Teng, Xiaochun zeng, Xuwei Luo, Tingjun Hu, Xianlong Huang, Jiankun Luo, Yongli Zhou
Atkinson cycle realized with a late intake valve closing (LIVC) and Miller cycle achieved with an early intake valve closing (EIVC) have been recognized as effective approaches for improving the gasoline engine fuel economy. In both Atkinson and Miller cycles, the engine can be designed with a higher geometric compression ratio for increasing the expansion work and the effective compression ratio is governed by the intake valve close (IVC) timing for the knock control. Duration of the intake event and IVC timing affect not only the pumping loss during the gas exchange, but also have strong influences on the friction torques of the intake cams and the turbulence intensities for the in-cylinder charge motion. The latter governs duration of combustion and EGR tolerance, both of which have impacts on the engine thermal efficiency.
2017-10-08
Technical Paper
2017-01-2455
Vikram Chopra
This paper reports on the design of a synchronizer brake based on permanent magnets, capable of braking with an active zero-slip load. Eddy-current brakes are widely used in automation and transportation applications; however, their use is limited by the rotor speed. For low-speed and high-torque applications, designs based on permanent magnets are better suited. Zero-slip braking torque is increased by the use of permanent magnets but, consequently, so is the cogging torque. At first, the synchronizer brake was designed with 16 surface magnets on the rotor. However, in order to reduce the permanent magnet mass, the rotor was re-designed with half the number of surface magnets. This novel design helped lower cogging torque and fabrication costs. Simulation of the design, using the 3D transient with motion solver in commercial finite element software, showed promising results.
2017-10-08
Technical Paper
2017-01-2202
Shiyou Yang
This work presents an application of two sub-models relative to chemical-kinetics-based turbulent pre-mixed combustion modeling approach on the simulation of burn rate and emissions of spark ignition engines. In present paper, the justification of turbulent pre-mixed combustion modeling directly based on chemical kinetics plus a turbulence model is given briefly. Two sub-models relative to this kind of pre-mixed combustion modeling approach are described generally, including a practical PRF (primary reference fuel) chemical kinetics mechanism which can correctly capture the laminar flame speed under a wide range of Ford SI (spark ignition) engines/operating conditions, and an advanced spark plug ignition model which has been developed by Ford recently.
2017-10-08
Technical Paper
2017-01-2355
Yungwan Kwak, Christopher Cleveland
Due to its simplicity and fuel economy benefit, continuously variable transmission (CVT) technology has gained a lot of attention in recent years. Market penetration of CVT technology is increasing rapidly compared to step-type automatic transmission technology. OEMs, Tier 1 suppliers, and lubricant suppliers are working to further improve the fuel economy benefit of CVTs. As a lubricant supplier, Afton Chemical Corporation has dedicated significant resources to understand the effects of fluid properties on CVT fuel economy. We have formulated fluids that had KV100 ranges from 3 cSt to 8 cSt with various types and viscosities of base oils. Wide ranges of viscosity indexes, steel-on-steel friction, and other properties were tested. Full vehicle fuel economy tests revealed that there was more than 3% overall variation compared to a reference fluid. Tests were performed in a temperature controlled environment with a robotic driver.
2017-10-08
Technical Paper
2017-01-2363
Murugesa Pandian M, Anand Krishnasamy
The major limitations in a conventional high temperature diesel combustion are higher oxides of nitrogen (NOx) and particular matter (PM) emissions and a trade-off between them. Advanced low temperature combustion (LTC) strategies are proposed to simultaneously reduce NOx and PM emissions to near zero levels along with higher thermal efficiencies. Various LTC strategies including Premixed Charge Compression Ignition (PCCI), Homogenous Charge Compression Ignition (HCCI), Reactivity Controlled Compression Ignition (RCCI), Stratified Charge Compression Ignition (SCCI) and High Efficiency Clean Combustion (HECC) are proposed so far to achieve near zero NOx and PM emissions along with higher thermal efficiencies. Each of these LTC strategies have their own advantages and limitations interms of precise ignition control, achievable load range and higher unburned emissions.
2017-10-08
Technical Paper
2017-01-2364
Jiaqiang Li, Yunshan Ge, Chao He, Jianwei Tan, Zihang Peng, Zidi Li, Wei Chen, Shijie Wang
Urea selective catalytic reduction is the most promising technique to reduce NOx emissions from heavy duty diesel engines. 32.5wt% aqueous urea solution is widely used as ammonia storage species for the urea selective catalytic reduction process. The thermolysis and hydrolysis of urea produces reducing agent ammonia and provides to catalysts to reduce NOx emissions to nitrogen and water. However, the application of urea SCR technology has many challenges at low temperature conditions, such as deposits formation in the exhaust pipe, lack deNOx performance at low temperature and freezing below -12℃. For preventing deposits formation, the aqueous urea solution is difficult to be injected into the exhaust gas stream at temperature below 200℃. The aqueous urea solution used as reducing agent precursor is the main obstacle for achieving high deNOx performances at low temperature conditions.
2017-10-08
Technical Paper
2017-01-2365
Murugesa Pandian M, Anand Krishnasamy
Reactivity controlled compression ignition (RCCI) is one of the most promising low temperature combustion (LTC) strategies to achieve higher thermal efficiencies along with ultra low oxides of nitrogen (NOx) and particulate matter emissions. Small single cylinder diesel engines of air-cooled type are finding increasing applications in the agriculture pump-set and small utility power generation owing to their lower cost and fuel economy advantages. In the present work, a small single cylinder diesel engine is initially operated under conventional combustion mode at rated speed, varying load conditions to establish the base line reference data. Then, the engine is modified to operate under RCCI combustion mode with a newly designed cylinder head to accommodate a high pressure, fully flexible electronically controlled direct diesel fuel injection system, a low pressure gasoline port fuel injection system and an intake air pre heater.
2017-10-08
Technical Paper
2017-01-2366
Wenzheng Xia, Yi Zheng, Xiaokun He, Dongxia Yang, Huifang Shao, Joesph Remias, Joseph Roos, Yinhui Wang
Because of the increased use of gasoline direct engine (GDI) in automobile industry, there is a significant need to control particulates from GDI engines based on emission regulations. One potential technical approach is the utilization of a gasoline particulate filter (GPF). The successful adoption of this emission control technology needs to take many aspects into consideration and requires a system approach for optimization. This study conducted research to investigate the impact of vehicle driving cycles, fuel properties, catalyst coating on the performance of GPF. It was found that driving cycle has significant impact on particulate emission. Fuel quality still plays a role in particulate emissions, and can affect the GPF performance. Catalyzed GPF is preferred for soot regeneration, especially for the case that the vehicle operation is dominated by congested city driving condition, i.e. low operating temperatures. The details of the study are presented in the paper.
2017-10-08
Technical Paper
2017-01-2367
Ganesan Mahadevan, Sendilvelan Subramanian
Control of harmful emissions during cold start of the engine has become a challenging task over the years due to the ever increasing stringent emission norms. Positioning the catalytic converter closer to the exhaust manifold is an efficient way of achieving rapid light-off temperature. On the other hand, the resulting higher thermal loading under high-load engine operation may substantially cause thermal degradation and accelerate catalyst ageing. The objective of the present work is to reduce the light-off time of the catalyst and at the same time reduce the thermal degradation and ageing of the catalyst to the minimum possible extent by adopting an approach with Dynamic Catalytic Converter System (DCCS). The emission tests were conducted at the cold start of a 4 cylinder spark ignition engine with DCCS at different positions of the catalyst at no load conditions.
2017-10-08
Technical Paper
2017-01-2244
Shui Yu, Xiao Yu, Zhenyi Yang, Meiping Wang, Xiaoye Han, Jimi Tjong, Ming Zheng
The fuel efficiency improvement of gasoline engines can be achieved through lean burn and/or exhaust gas recirculation (EGR). However, the ignition of a diluted cylinder charge tends to be more diverged, owing to the slower ignition and combustion processes. The operable range of diluted combustion in gasoline engines is often limited, e.g. with lambda below 2.0 or EGR rate lower than 30%, owing to the deterioration in mixture ignitability and severe cyclic variations. In addition, the adoption of intensified cylinder charge motion requires further optimizations of ignition system, including the igniter geometric configurations and the temporal modulations over ignition energy delivery and spark discharge pattern. In this work, a variety of spark ignition approaches are investigated to improve the ignition of diluted gasoline engine under homogeneous mixture mode. A spatially distributed spark arcing control is realized based on a three-pole igniter.
2017-10-08
Technical Paper
2017-01-2254
Sirui Huang, Changpu Zhao, Yayong Zhu
In order to improve the combustion and emissions for high-speed marine diesel engines, numerical investigations on effects of different combustion chamber structures combined with intake air humidification have to be conducted in this paper. The study uses AVL Fire code to establish three-dimensional combustion model and simulate the in-cylinder flow, air-fuel mixing and combustion process with the flow dynamics metrics such as swirl number and uniformity index, analyze the interactional effects of combustion chamber structures and intake air humidification against the experimental data for a part load operation at 1350 r/min, find the optimized way to improve engine performance as well as decrease the NOx and soot emissions. The novelty is that this study is to combine different air humidifying rates with different combustion chamber structures including the re-entrant chamber, the straight chamber and the open chamber.
2017-10-08
Technical Paper
2017-01-2256
Muhammad Umer Waqas, Kai Morganti, Jean-Baptiste Masurier, Bengt Johansson
Future internal combustion engines demand higher efficiency, progression towards is limited by antiknock quality of present fuels and energy economics in octane enhancement. A possible solution is Octane-on-Demand, that uses a combination of high and low octane fuels in separated tanks to generate fuels of the required octane rating according to demand. Methanol, a RON 109 fuel was selected as the high octane fuel and five low octane fuels were used as base fuel. These were FACE (Fuels for Advanced Combustion Engines) gasolines, more specifically FACE I, J and A and their primary reference fuels (iso-octane/n-heptane). Experiments were conducted with a modified Cooperative Fuel Research (CFR) engine. For SI combustion mode the CFR operated at RON and MON conditions. The engine i.e. also operated in HCCI mode to get the auto ignition properties at lean conditions (λ=3).
2017-10-08
Technical Paper
2017-01-2262
Changle Li, Per Tunestal, Martin Tuner, Bengt Johansson
In a former research, the sensitivity of combustion phasing to intake temperature and injection timing during the transition from HCCI to PPC were investigated, fueling with generic gasoline. While digging into the results, special interest was drawn into the relationship between the intake temperature and combustion phasing since it was believed that it properly revealed the changing of stratification level with the injection timing. To confirm its applicability on different fuels also investigate the effect of fuel properties on the formation of stratification, primary reference fuels (PRF) was tested with the same method: a start of injection sweep from -180° to -20° aTDC (after top dead center) with the combustion phasing kept constant by tuning the intake temperature. The results were compared with the former results of gasoline, and the previous conclusions were further developed. A three-stage fuel-air stratification development process, from HCCI to PPC, was observed.
2017-10-08
Technical Paper
2017-01-2263
S. Vedharaj, R Vallinayagam, Yanzhao An, Mohammad Izadi Najafabadi, Bart Somers, Junseok Chang, Bengt Johansson
Naphtha boils in the gasoline range of 40°C to 75°C with a RON of 65, showing increased resistance to auto-ignition. It is not possible to use naphtha as a drop in fuel for CI engine and therefore, it is ideal to investigate premixed combustion of naphtha. Previous studies reports the use of naphtha in CI engine under partially premixed combustion (PPC) mode, wherein the fuel injection timing and intake air temperature controls combustion. In this study, we investigate the combustion visualization and stratification of surrogate fuel in PPC mode. The composition of naphtha surrogate is 2-methyl butane (0.21% mol), 2-methyl hexane (0.07% mol), n-pentane (0.6% mol), n-heptane (0.07% mol) and toluene (0.05% mol). Investigation of surrogate fuel in engine expands on the previous studies on surrogate fuel formation for naphtha. Based on the experimental outcome, start of injection (SOI) was found to be inversely correlated with combustion phasing during early injection timings.
2017-10-08
Technical Paper
2017-01-2266
Bin Yang, Hu Wang, Mingfa Yao, Zunqing Zheng, Jialin Liu, Naifeng Ma, Qiping Wang, Haien Zha, Peng Chen
Gasoline partially premixed combustion shows the potential to achieve clean and high efficiency combustion. Injection strategies show significant influence on in-cylinder air flow and in-cylinder concentration distribution before auto-ignition, which can significantly affect the combustion characteristics and emissions. This study explored the effects of various injection strategies, including port fuel injection (PFI), single direct injection (DI), double direct injection (DIP+DIM) and port fuel injection coupled with a direct injection (PFI+DIM) on the combustion characteristics and emissions on a modified single cylinder heavy duty diesel engine fueled with 92# gasoline. The results showed that CA5 and CA50 of DIP+DIM are more sensitive to injection timing than PFI+DIM and single direct injection strategy, partially due to the effects of DIP on mixture stratification and low temperature reaction of gasoline.
2017-10-08
Technical Paper
2017-01-2278
Zhiwei Deng, Ang Li, Lei Zhu, Zhen Huang
In-cylinder thermochemical fuel reforming (TFR) in spark ignition nature gas engine was developed to reveal that thermochemical fuel reforming could increase H2 and CO concentration in reformed gas, leading to an increase of thermal efficiency and engine performance. Moreover, ethanol enrichment has been proved to have great potential to optimize TFR performance. In order to explain TFR phenomenon chemically, methane oxidation experiments were conducted in a laminar flow reactor with addition of ethanol and methanol at equivalent ratios of 1.5, 1.7, 1.9 and 2.1 from 948K to 1098K at atmospheric pressure. Experimental results showed that methanol have great ability to facilitate the oxidation of methane than that of ethanol. Meanwhile, the degree of methane conversion became more significantly as the equivalent ratio increased. Kinetic analysis of oxidation of methane with alcohol enrichment in a plug flow model was also conducted in this study.
2017-10-08
Technical Paper
2017-01-2277
Xiao Peng, Han Wu, Chia-Fon Lee, Qianbo Sun, Fushui Liu
Methanol has been regarded as a potential transportation fuel due to its advanced combustion characteristics and flexible source. However, it is suffering from misfire and high HC emissions problems under cold start and low load conditions either on methanol SI engine or on methanol/diesel dual fuel engine. Hydrogen is a potential addition that can enhance the combustion of methanol due to its high flammability and combustion stability. In the current work, the effect of hydrogen fraction on the laminar flame characteristics of methanol- hydrogen-air mixture under varied equivalence ratio was investigated on a constant volume combustion chamber system coupled with a schlieren setup. Experiments were performed over a wide range of equivalence ratio of the premixed charge, varied from 0.8 to 1.4, as well as different hydrogen fraction, 0%, 5%, 10%, 15% and 20% (n/n). All tests were carried out at fixed temperature and pressure of 400K and 0.1MPa.
Viewing 61 to 90 of 110594