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Influence of the Injector Geometry at 250 MPa Injection in a Light-Duty Diesel Engine

Korea Advanced Institute of Science and Technology-Seungwoo Kang, Wonkyu Cho, Choongsik Bae
Hyundai Motor Company-Youngho Kim
Published 2017-03-28 by SAE International in United States
This paper investigated the influence of the injector nozzle geometry on fuel consumption and exhaust emission characteristics of a light-duty diesel engine with 250 MPa injection. The engine used for the experiment was the 0.4L single-cylinder compression ignition engine. The diesel fuel injection equipment was operated under 250MPa injection pressure. Three injectors with nozzle hole number of 8 to 10 were compared. As the nozzle number of the injector increased, the orifice diameter decreased 105 μm to 95 μm. The ignition delay was shorter with larger nozzle number and smaller orifice diameter. Without EGR, the particulate matter(PM) emission was lower with larger nozzle hole number. This result shows that the atomization of the fuel was improved with the smaller orifice diameter and the fuel spray area was kept same with larger nozzle number. However, the NOx-PM trade-offs of three injectors were similar at higher EGR rate and higher injection pressure. The effect of high injection pressure was dominant for reducing PM emissions, and the effect of nozzle geometry on the PM emissions wasn’t distinguishable at…
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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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Experimental Characterization of DI Gasoline Injection Processes

Korea Advanced Institute of Science and Technology-Yongjin Jung
Delphi Powertrain Systems-Lee Markle
Published 2015-09-01 by SAE International in United States
This work investigates the injection processes of an eight-hole direct-injection gasoline injector from the Engine Combustion Network (ECN) effort on gasoline sprays (Spray G). Experiments are performed at identical operating conditions by multiple institutions using standardized procedures to provide high-quality target datasets for CFD spray modeling improvement. The initial conditions set by the ECN gasoline spray community (Spray G: Ambient temperature: 573 K, ambient density: 3.5 kg/m3 (∼6 bar), fuel: iso-octane, and injection pressure: 200 bar) are examined along with additional conditions to extend the dataset covering a broader operating range. Two institutes evaluated the liquid and vapor penetration characteristics of a particular 8-hole, 80° full-angle, Spray G injector (injector #28) using Mie scattering (liquid) and schlieren (vapor). Diffused back-illumination (DBI) imaging, which is the ECN standard liquid length diagnostic, was also used to provide a reference for the Mie scatter measurements. In addition to imaging the full liquid field, the DBI measurements included long-distance microscopy collection to permit characterization of near-nozzle, end-of-injection details. Interpretation of plume-to-plume variation was assisted by nozzle geometry measurements performed…
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Assessment of the Ignition and Lift-off Characteristics of a Diesel Spray with a Transient Spreading Angle

Korea Advanced Institute of Science and Technology-Yongjin Jung
Sandia National Laboratories-Julien Manin, Scott A. Skeen, Lyle M. Pickett
Published 2015-09-01 by SAE International in United States
Multi-hole diesel fuel injectors have shown significant transients in spreading angle during injections, different than past fundamental research using single-hole injectors. We investigated the effect of a this transient spreading angle on combustion parameters such as ignition delay and lift-off length by comparing a three-hole nozzle (Spray B) and single-hole nozzle (Spray A) with holes of the same size and shape as targets for the Engine Combustion Network (ECN). With the temperature distribution for a target plume of Spray B characterized extensively in a constant-volume combustion chamber, the ignition delay and lift-off length were measured and compared. Results show that the lift-off length of Spray B increases and grows by approximately 1.5 mm after the initial stages of ignition, in an opposite trend compared to Spray A where the lift-off length decreases with time. The Spray B lift-off length increase is consistent with a transition to from wide to narrow spreading angle that would tend to increase lift-off length, but lift-off is stabilized for a substantial period of time by a wide annular region of…
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Effects of Hydrogen Ratio and EGR on Combustion and Emissions in a Hydrogen/Diesel Dual-Fuel PCCI Engine

Korea Advanced Institute of Science and Technology-Hyunwook Park, Jaeheun Kim, Choongsik Bae
Published 2015-09-01 by SAE International in United States
The effects of hydrogen ratio and exhaust gas recirculation (EGR) on combustion and emissions in a hydrogen/diesel dual-fuel premixed charge compression ignition (PCCI) engine were investigated. The control of combustion phasing could be improved using hydrogen enrichment and EGR due to the retarded combustion phasing with a higher hydrogen ratio. The indicated mean effective pressure (IMEP) was increased with a higher hydrogen ratio because the hydrogen enrichment intensified the high temperature reactions and thus decreased the combustion duration. Hydrocarbon (HC) and carbon monoxide (CO) emissions were reduced significantly in a hydrogen/diesel dual-fuel PCCI mode with a similar NOx emissions level as that of the diesel PCCI mode.
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Evaluation Model for Lithium-Ion Battery Deterioration (First Report)

Korea Advanced Institute of Science and Technology-Hiromichi Akimoto
Japan Automobile Research Institute-Daichi Imamura
  • Technical Paper
  • 2012-08-0514
Published 2012-10-03 by Society of Automotive Engineers of Japan in Japan
Lithium-ion Batteries (LiB) are increasingly being used in automobiles and buildings since the late 2000s. Although the lifetime of several years is long enough for LiB used for electronic devices, a lifetime of more than 10 years is required for LiB in infrastructure. However, users of LiB are submitting to the uncertainty of the lifetime of LiB. This problem is one of the causes which prevent the spread of use of LiB. Therefore, it is important to predict the degradation of battery performance, evaluate the lifetime of LiB based on present performance and how to use them in the future. Our team developed an evaluation model for used LiB, which contains two elements: Degradation speed database based on experiment and the method of setting up the use pattern of LiB.
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Clutchless Geared Smart Transmission

Korea Advanced Institute of Science and Technology-Yong-San Yoon, Kyung Soo Kim, Sun Je Kim
Published 2011-08-30 by SAE International in United States
Most passenger vehicles employ manual or automatic transmission in their power train. Recently, some automated geared transmission including the dual clutch transmission is gaining popularity for its fuel efficiency and smooth driving as well as convenience. In this study, we are proposing a new much simplified clutchless geared transmission which may transmit most powerful torque employing the power-merge planetary gear system to the final drive during gear shift with excellent smoothness in the transmitted torque. This transmission might work for the most kinds of vehicles having internal combustion engine including the hybrid vehicles.
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Effects of EGR and DME Injection Strategy in Hydrogen-DME Compression Ignition Engine

Korea Advanced Institute of Science and Technology-Jeeyeon Jeon, Choongsik Bae
Published 2011-08-30 by SAE International in United States
The compression ignition combustion fuelled with hydrogen and dimethyl-ether was investigated. Exhaust gas recirculation was applied to reduce noise and nitrogen oxide (NOx) emission. When dimethyl-ether was injected earlier, combustion showed two-stage ignitions known as low temperature reaction and high temperature reaction. With advanced dimethyl-ether injection, combustion temperature and in-cylinder pressure rise were lowered which resulted in high carbon monoxide and hydrocarbon emissions. However, NOx emission was decreased due to relatively low combustion temperature. The engine combustion showed only high temperature reaction when dimethyl-ether was injected near top dead center. When exhaust gas recirculation gas was added, the in-cylinder pressure and heat release rate were decreased. However, it retarded combustion phase resulting in higher indicated mean effective pressure. The carbon monoxide and hydrocarbon emissions were increased and NOx emission was decreased with exhaust gas recirculation was added. In this study, low-emission, hydrogen-DME compression ignition engine was achieved through the DME injection strategy and EGR.
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The Effect of Injection Location of DME and LPG in a Dual Fuel HCCI Engine

Korea Advanced Institute of Science and Technology-Jinyoung Jang, Kiseon Yang, Choongsik Bae
Published 2009-06-15 by SAE International in United States
Dimethyl ether (DME) as a high cetane number fuel and liquefied petroleum gas (LPG) as a high octane number fuel were supplied together to evaluate the controllability of combustion phase and improvement of power and exhaust emission in homogeneous charge compression ignition (HCCI) engine. Each fuel was injected at the intake port and in the cylinder separately during the same cycle, i.e., DME in the cylinder and LPG at the intake port, or vice versa. Direct injection timing was varied from 200 to 340 crank angle degree (CAD) while port injection timing was fixed at 20 CAD.In general, the experimental results showed that DME direct injection with LPG port injection was the better way to increase the IMEP and reduce emissions. The direct injection timing of high cetane number fuel was important to control the auto-ignition timing because the auto-ignition was occurred at proper area, where the air and high cetane number fuel were well mixed. In the case of port injection with high cetane number fuel, performance was limited due to early or constant…
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Operating Range of Low Temperature Diesel Combustion with Supercharging

Korea Advanced Institute of Science and Technology-Sangwook Han, Euijoon Shim, Jinyoung Jang, Jungseo Park, Choongsik Bae
Ssangyong Motor Company-Jongnam Park, Hyunok Kim
Published 2009-04-20 by SAE International in United States
Low temperature diesel combustion with a large amount of exhaust gas recirculation in a direct injection diesel engine was investigated. Tests were carried out under various engine speeds, injection pressures, injection timings, and injection quantities. Exhaust emissions and brake specific fuel consumption were measured at different torque and engine speed conditions. High rates of exhaust gas recirculation led to the simultaneous reduction of nitrogen oxide and soot emissions due to a lower combustion temperature than conventional diesel combustion. However, hydrocarbon and carbon monoxide emissions increased as the combustion temperature decreased because of incomplete combustion and the lack of an oxidation reaction.To overcome the operating range limits of low temperature diesel combustion, increased intake pressure with a modified turbocharger was employed. As a result of adopting increased intake pressure in low temperature diesel combustion, wider operating range was achieved compared with naturally aspirated condition. This is because relatively complete combustion occurred because of more air utilization under these conditions. Moreover, increased intake pressure resulted in lower hydrocarbon and carbon monoxide emissions due to a higher oxygen…
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