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JSAE/SAE 2015 International Powertrains, Fuels & Lubricants Meeting
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Effects of High-Response TiAl Turbine Wheel on Engine Performance under Transient Conditions

Korea Advanced Institute of Science and Technology-Jinyoung Jung, Chansoo Park, Choongsik Bae
Published 2015-09-01 by SAE International in United States
Transient tests in a 2.0 liter in-line 4 cylinder downsizing gasoline direct injection engine were conducted under various transient conditions in order to investigate effects of lower rotational inertia of titanium aluminide alloy (TiAl) turbine wheel on engine and turbocharger performances. As a representative result, fast boost pressure build up was achieved in case of TiAl turbocharger compared to Inconel turbocharger. This result was mainly due to lower rotational inertia of TiAl turbine wheel. Engine torque build up response was also improved with TiAl turbocharger even though engine torque response gap between both turbochargers was slightly reduced due to retarded combustion phase. In addition, with advanced ignition timing, fuel consumption became less than that of Inconel turbocharger with similar engine torque response.
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Researches of Double-Layer Diverging Combustion System (DLDCS) in a DI Diesel Engine

Dalian University of Technology-Wuqiang Long, Yao Fu, Jiangping Tian, Shuang He
Dalian University of Technology Shenyang Aerospace Univ.-Lei Chen, Kunpeng Qi
Published 2015-09-01 by SAE International in United States
The new DI diesel engine combustion system named Double-Layer Diverging Combustion System (DLDCS) results in a better Brake Specific Fuel Consumption (BSFC) and lower exhaust emissions. The previous results of numerical simulation and bench test of a single cylinder DI diesel engine showed that more homogeneous fuel distribution, better BSFC and lower emission level were obtained by employing this combustion system. In this research, further numerical simulation are employed to seek the best injection advance angle and investigate the influence of different volume fraction and type lines of upper layer with AVL Fire.
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Spray Characteristics and Inside Flow of a Marine Diesel Injector

Mitsui Engineering & Shipbuilding-Sumito Yokobe
Tottori University-Tetsuya Oda, Katsuyuki Ohsawa, Takahiro Sumi, Shuhei Sugata, Keiichiro Yabuta
Published 2015-09-01 by SAE International in United States
The spray characteristics and inside flow of a marine diesel injector were investigated both experimentally and numerically. From the experiments, we observed that the penetration of the sprays in the early injection stage gradually increases. This phenomenon differs significantly from that of the small automobile diesel injector, in which penetration increases linearly with time. Using the momentum method to obtain injection rate measurements, we observed an injection rate spike at each injection event just after the injection began. The observed spray results show that the small portion of fuel remaining inside the nozzle from the previous injection event is ejected first, and then the main volume of fuel is ejected. Both fuels accumulate as spray droplets and gradually accelerate after the early injection stage. Numerical simulations of the injector's inside flow show that the fuel injection rate becomes saturated in needle lifts larger than 0.3 mm. Cavitation can be observed around the needle seat for smaller needle lifts. A larger cavitation area appears around the needle seat during the lifting movements than during the closing…
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High-Speed Observation and Modeling of Dimethyl Ether Spray Combustion at Engine-Like Conditions

SAE International Journal of Engines

Ibaraki University-Yuta Mitsugi, Daiki Wakabayashi, Kotaro Tanaka, Mitsuru Konno
  • Journal Article
  • 2015-01-1927
Published 2015-09-01 by SAE International in United States
Dimethyl Ether (DME) is one of the major candidates for the alternative fuel for compression ignition (CI) engines. However, DME spray combustion characteristics are not well understood. There is no spray model validated against spray experiments at high-temperature and high-pressure relevant to combustion chambers of engines. DME has a lower viscosity and lower volumetric modulus of elasticity. It is difficult to increase injection pressure. The injection pressure remains low at 60 MPa even in the latest DME engine. To improve engine performance and reduce emissions from DME engines, establishing the DME spray model applicable to numerical engine simulation is required.In this study, high-speed observation of DME sprays at injection pressures up to 120 MPa with a latest common rail DME injection system was conducted in a constant volume combustion vessel, under ambient temperature and pressure of 6 MPa-920 K. The spray penetration, evaporation, liquid length and ignition delay were investigated and compared with those of diesel sprays. Based on the observed results, the spray model of DME was developed. A reduced chemical kinetic model for…
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Effect of Spark Timing and Load on Combustion and Emission Characteristics in Jet Controlled Compression Ignition

Xiangyu Meng
Institute of Internal Combustion Engine, Dalian Univ.-Wuqiang Long, Qiang Zhang, Jiangping Tian, Hua Tian
Published 2015-09-01 by SAE International in United States
A novel combustion system called Jet Controlled Compression Ignition (JCCI) is investigated to directly control the combustion phasing of premixed diesel compression ignition. Experiments were conducted on a single-cylinder naturally aspirated diesel engine at 3000r/min without EGR. The experimental results showed a good linear relationship between spark timing in the ignition chamber and CA10 and CA50, which indicated the ability for direct combustion phasing control in premixed diesel combustion. The NOx and soot emissions gradually changed with the spark advance angle. Then, load sweep experiments were performed with fixed spark timing. The results showed the onset of combustion was almost unchanged over a wide load range. Additionally, NOx emission was greatly reduced at all test loads compared with the original engine. Soot emission was reduced at a comparatively high load while similar with that of the original engine at low loads. The maximum reduction of NOx and Soot were both over 90%.
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Fuel Borne Catalyst Assisted Diesel Particulate Filter Regeneration in Current and Legacy Retrofitted Vehicles in China

College of Military Transportation-Jiang Dahai
Infineum UK, Ltd.-Rinaldo Caprotti, Romaeo Dallanegra
Published 2015-09-01 by SAE International in United States
Retrofitting current and legacy diesel vehicles with Diesel Particulate Filters (DPFs) and associated aftertreatment technology has long been an option to enable vehicles with older engines to meet specific regional emissions legislation. A major positive is the ability for enforced vehicle retrofitting to have an immediate impact on the local air quality in urban environments without vehicle owners having to purchase new vehicles. Retrofit in China in comparison to Europe, for example, is in its relative infancy as China's emission legislation rapidly moves towards adopting European like limits whilst available diesel fuel continues to have variable sulphur concentrations.This paper details the results from a two phase retrofit-study conducted to investigate the ability for Fuel Borne Catalyst (FBC) technology to regenerate DPFs in retrofitted Light Duty (LD) vehicles in China. Phase 1 discusses an initial 100,000 km field trial across China over a pre-selected route to gain proof of concept. Phase 2 details a multiple vehicle study run in Tianjin using an FBC-DPF strategy. Both trial phases highlight that FBC technology is a robust and reliable…
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Injection Strategy Study of Compression Ignition Engine Fueled with Naphtha

Tsinghua University-Changsheng Yao, Fuyuan Yang, Jinli Wang, Haiyan Huang, Minggao Ouyang
Published 2015-09-01 by SAE International in United States
This study investigates the performance of a diesel engine fueled with naphtha under different load by varying injection parameters and exhaust gas recirculation (EGR) rate. The experiments were conducted on a 1.9-liter common rail diesel engine with a compression ratio of 17.5. Naphtha with a research octane number of 60.5 was tested. Three multi-injection strategies were designed. Each injection strategy, aided with EGR, conducts a characteristic combustion mode. Multi-injection strategies and single-injection strategy were tested and compared at one operating point under different main injection timing and EGR conditions. Results indicate that the well-designed multi-injection strategy has advantages over the single injection strategy in lowering noise, emissions and improving combustion efficiency. Among the three strategies, the strategy with 15-degree pilot timing and 2mg/cycle pilot injection could achieve both low NOx and PM emissions without sacrificing much fuel efficiency. For example, one of the operating points reached with 49% EGR rate has mean IMEP of 5.68 bar, NOx emission of 20ppm, PM emission of 1.8×106/mm3, HC emission of 45 ppm and the rate of pressure rise…
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Inverted Brayton Cycle Employment for a Highly Downsized Turbocharged Gasoline Engine

Univ. of Bath-Zhihang Chen, Colin D. Copeland
Published 2015-09-01 by SAE International in United States
The study presented in this paper aims to evaluate the performance of a new conceptual combined power system composed of a turbocharged engine and an inverted Brayton cycle (IBC). A validated 1D model of a downsized SI engine has been built in GT-power as the baseline model to quantify the performance improvement due to introducing the inverted Brayton cycle. The results show that a system performance improvement caused by adopting IBC is expected depended on the engine load, IBC turbomachinery efficiency and the bottoming expansion ratio. The maximum thermal efficiency of the combined system is achieved when both the wastegates of turbocharger and IBC turbines are closed, which is up to 6.15 percent point.
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Multi-Phase Simulation for Predicting Better Groove Pattern of the Clutch Disk for Low Drag Torque

Dynax Corp.-Syeda Faria Mahmud, Shahjada A. Pahlovy, M. Kubota, Makoto Ogawa, Norio Takakura
Published 2015-09-01 by SAE International in United States
In this research, we presented a simulation model based on hexahedral mesh, Laminar and Volume of fluid (VOF) flow models to predict the better groove pattern of transmission clutch plate. Significance of Hexahedral (Hex) mesh over Polyhedral-Prism layer (PPL) mesh model has been explained as well. Simulation results reflect close similarity with the test results. The difference of drag torque characteristics for different groove shape has been explained via particle tracking and scalar plots. Test and simulation results show that around 50% drag loss reduction is possible by effective design of the grooves. Therefore, our proposed simulation model offers a cost-effective and time-saving means to select the best groove profile and optimize the groove shape to minimize transmission drag loss
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Numerical Investigation of a Potential of Dedicated EGR System for Increasing Thermal Efficiency of SI Engines Fueled with Methane and Propane

Keio University-Sejun Lee, Norimasa Iida
Osaka Gas Co., Ltd.-Takahiro Sako
Published 2015-09-01 by SAE International in United States
This study tried to find a potential of dedicated EGR (d-EGR) system added to the four-cylinder spark ignition (SI) engine to decrease heat loss (Qheatloss) and improve thermal efficiency (ηth). Test fuels were chosen by methane and propane. PREMIX code in CHEMKIN-PRO was employed to calculate laminar burning velocity (SL) and flame temperature (Tf). Wiebe function and Wocshni's heat transfer coefficient were considered to calculate ηth. The results show that the d-EGR system increased ηth and it was higher than that of stoichiometric combustion of conventional SI engines due to the low Tf and fast SL.
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