• Transactions of the Korean Society of Automotive Engineers
• /
• v.6 no.3
• /
• pp.115-122
• /
• 1998

For digital engine control timings, such as ignition, are based on the crank shaft angle. Therefore, it is very important that the angle of the crank shaft can be detected with accuracy for optimal ignition timing. Sequential multi-point injection(MPI) systems that have independent injection events for each cylinder, are used to inject an accurate quantity of fuel, and to cope with varying engine status promptly. In this study the distributorless ignition timing. A crankshaft position sensor has been installed such that it generates a number of pulses per crankshaft revolution to permit accurate detection of the crank shaft angle. An event detecting algorithm has been developed, which detects the crank shaft pulses generated by the position sensor, and the software outputs the required control signals at given crank angle values. We clarified that the hardware method is the best way to increase the performance of the control system, because the event detecting duration T(1+2)max becomes zero.

• Design & Manufacturing
• /
• v.6 no.2
• /
• pp.31-36
• /
• 2012

Now days CAE has been used for almost all injection molding designs in order to find the best injection conditions. Almost all CAE use 2-D mesh, but the CAE with 2-D mesh can't indicate such as jetting, flow-mark and filling imbalance in multi cavity mold. In this study, we suggested a new 3D meshing. the method which can indicate the filling imbalance in geometrically balanced runner system with Mold Flow MPI 6.1 and we found out that the calculation times are saved. As a feasibility study, we verified that Melt Flipper, RC Pin etc appeared the balanced filling behaviors. of geometrically balanced runner system and Melt Flipper, filling imbalance was indicated more accurately.

• 한국금형공학회:학술대회논문집
• /
• 2008.06a
• /
• pp.121-127
• /
• 2008

Nowdays CAE has been used for almost all injection molding designs in order to find the best injection conditions. Almost all CAE use 2-D mesh, but the CAE with 2-D mesh can't indicate such as jetting, flow-mark and filling imbalance in multi cavity mold. In this study, we suggested a new 3D meshing. the method which can indicate the filling imbalance in geometrically balanced runner system with Mold Flow MPI 6.1 and we found out that the calculation times are saved. As a feasibility study, we verified that Melt Flipper, RC Pin etc appeared the balanced filling behaviors. of geometrically balanced runner system and Melt Flipper, filling imbalance was indicated more accurately.

• Journal of Energy Engineering
• /
• v.25 no.4
• /
• pp.159-169
• /
• 2016

In this study, the effects of MTBE contents as oxygenates in gasoline on exhaust emissions and fuel economy in MPI and GDi vehicles have been investigated. Various oxygen contents have been selected such as 0, 1.0, 2.3 and 2.7 wt%. FTP-75 and HWFET modes as fuel economy test methods which are widely used in Republic of Korea and US were applied to investigate exhaust emissions from the test vehicles. Emissions of CO, NMHC and NOx did not show significant correlation with oxygen contents in gasoline fuels, although having slight difference with these contents. In addition, CO2 emissions were not significantly changed with respect to oxygen content. But in case of warm-up and FTP-75 and HWFET modes including high speed regimes, CO2 emissions showed inverse correlation with oxygen contents. Particulate number concentration was inversely proportional to the oxygen contents, having the minimum value at the condition of 2.3 wt%. In case of fuel economy through carbon balance method, the highest value has been obtained at 2.3 wt% and there was positive correlation with oxygen contents and fuel economy.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.38 no.10
• /
• pp.837-844
• /
• 2014

Automotive manufacturers have recently developed various technologies for improving fuel economy and satisfying enhanced emission regulations. The ultra-lean direct injection engine is a promising technology because it has the advantage of improving thermal efficiency through the deliberate control of ignition. A conventional LPG engine has been redesigned to an ultra-lean-burn LPG direct injection engine in order to adopt combustion system of ultra-lean-burn. This study is aimed at investigating the effect of a change in the compression ratio on the performance and emission characteristics of a lean-burn LPG engine. The fuel consumption, heat release rate, combustion pressure, and emission characteristics are estimated depending on changing the effect of compression ratio. When the compression ratio is increased, it is difficult to improve the fuel consumption owing to an unstable combustion state, but the total hydrocarbon and nitrogen oxide emissions are reduced.

• Journal of ILASS-Korea
• /
• v.16 no.2
• /
• pp.97-103
• /
• 2011

The electronically controlled diesel engine was converted to dual fuel engine system. Test engine was set up for investigating the power output, thermal efficiency and emissions. ND 13-mode tests were employed for the engine test cycle. The emission result of dual fuel mode meets Euro-4 (K2006) regulation and the engine performance of dual fuel engine was comparable to the performance of diesel engine. To estimate economical efficiency, test vehicles have been operated on a certain driving route repeatedly. Fuel economy, maximum driving distance per refueling and driveability were examined on the road including free ways. Developed vehicle can be operated over 500 km with dual fuel mode and shows 80% of diesel substitution ratio. Driveability of dual fuel mode is similar with that of diesel mode.

• Applied Chemistry for Engineering
• /
• v.18 no.5
• /
• pp.407-414
• /
• 2007

Using the MPI (Moldflow Plastics Insight) software from Moldflow Co., the optimum conditions for producing the upper part of the automobile air cleaner were obtained for 20% talc filled polypropylene (PP). The analysis was carried out to solve the cracking problem between upper and lower parts and the improved process was proposed using the flow balance. The comparative results between the conventional process, CASE-1, with one-pin gate and the new process (CASE-2) comprising two-pin gate system are the followings. In the case of CASE-2, the shorter filling time and reduced cycle time induced an improved production and processibility. In addition, the orientation and volumetric shrinkage are similar to those observed in the lower part, but the assembly, deformation, and physical characteristics are enhanced. The problem induced by the CASE-1 did not originate from the residual stress, but from the difference in the size of the upper part air cleaner after shrinkage. Thus, the orientation problem was expected to improve by optimizing the gate structure.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.37 no.6
• /
• pp.607-614
• /
• 2013

Nowadays, automotive manufacturers have developed various technologies to improve fuel economy and reduce harmful emissions. The ultra-lean direct injection engine is a promising technology because it has the advantage of improving thermal efficiency through the deliberate control of fuel and ignition. This study aims to investigate the development of a spray-guided-type lean-burn LPG direct injection engine through the redesign of the combustion system. This engine uses a central-injection-type cylinder head in which the injector is installed adjacent to the spark plug. Fuel consumption and combustion stability were estimated depending on the ignition timing and injection timing at various air-fuel ratios. The optimal injection timing and ignition timing were based on the best fuel consumption and combustion stability.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.39 no.4
• /
• pp.351-358
• /
• 2015

In the recent times, the use of gasoline direct injection (GDI) engines has been regarded as a means of enhancing conformance to emission regulations and improving fuel efficiency. GDI engines have been widely adopted in the recent years for their better engine performance and fuel economy compared to those of conventional MPI gasoline engines. However, they present some disadvantages related to the mass and quantity of particulate matter generated during their use. This study investigated the nanoparticle characteristics of the particulate matter exhausted from a GDI engine vehicle installed with different types of gasoline particulate filters, after subjecting it to ultra-lean burn driving conditions. Three metal foam and metal fiber filters were used for each experimental condition. The number concentrations of particles were analyzed for understanding their behavior, and the reduction characteristics were obtained for each type of filter.

• Journal of Powder Materials
• /
• v.21 no.3
• /
• pp.215-221
• /
• 2014

Translucent alumina is a potential candidate for high temperature application as a replacement of the glass or polymer. Recently, due to the increasing demand of high power light emitting diode (LED), there is a growing interest in the translucent alumina. Since the translucent property is very sensitive to the internal defect, such as voids inside or abnormal grain growth of sintered alumina, it is important to fabricate the defect-free product through the fabrication process. Powder injection molding (PIM) has been commonly applied for the fabrication of complex shaped products. Among the many parameters of PIM, the flowability of powder/binder mixture becomes more significant especially for the shape of the cavity with thin thickness. Two different positions of the gate were applied during PIM using the disc type of die. The binder was removed by solvent extraction method and the brown compact was sintered at $1750^{\circ}C$ for 3 hours in a vacuum. The flowability was also simulated using moldflow (MPI 6.0) with two different types of gate. The effect of the flowability of powder/binder mixture on the microstructure of the sintered specimen was studied with the analysis of the simulation result.