• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.3
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• pp.796-805
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• 1995

For the purpose of improving performances of a turbocharged diesel engine at low speed, this study investigates the effects of the injected air for the performances and flow characteristics in the intake and exhaust pipes by using the computer simulation with test bed. In the theoretical analysis, the whole flow system, including engine cylinders and intake and exhaust pipes, is calculated numerically by the method of filling and emptying. From the results of this study, the following conclusions may be summarized. Increasing injected air pressure into the pipe of compressor exit brings about the improvement in a performance and flow characteristics of intake and exhaust pipes under full load operating conditions at 1000 rpm of the engine speed, but shows trends of the inferior performances under no load operating conditions at 2000 rpm of the engine speed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.04a
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• pp.214-216
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• 2012

This paper relates to the automotive silencers reduce noise generated from the actual vehicle for the activity is based on was worth. To do this, the noise from cars to distinguish them by category, characteristics of turbo charger was designed to reduce noise. In order for the design of acoustic modeling using line dynamics, was analyzed using In house & the commercial software programs. Silencers have about several basic elements. Expand, collapse, perforated plate, and the combination are the basic reactive or dissipative elements. Finally, DFSS(design for six sigma) method was designed. and it was verified in vehicle test. The new developed silencers showed good performance vehicle test results. also, the net cost also indicated excellent results compared with other company.

• Journal of Power System Engineering
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• v.9 no.1
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• pp.50-56
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• 2005

The corrosion experiment was performed for 120 hours on the specimens in the natural seawater tank with four steps of the loaded torsional stress. The surface corrosion pattern of SCM440 area was showed global corrosion and narrow pitting, that was cause by galvanic corrosion between friction welded IN713LC and SCM440. But corrosion does not proceeded from IN713LC area. Initially, the average relative electrode potential and corrosion current were decreased suddenly, by and large, it was stabilized gradually tend to decreasing with the elapse of the immersion time. The corrosion rate was decreased by increasing the load stress, but 200 MPa specimen was showed most large value.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.29 no.3
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• pp.220-228
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• 1993

This paper presents a description and evaluation of a detailed mathematical simulation for the steady and unsteady flow in a radial inflow-turbine which is most frequently used, at present, for exhaust gas turbochargers of internal combustion engines. As a method of computation, the two-step differential Lax-Wendroff method and the characteristic method were used. The turbine characteristics, the mass flow rate, the power output and fluid movements at the turbine scroll inlet were compared with the experiment data. The results of the simulation were in good agreement with experimental values under both steady and unsteady flow conditions.

• Transactions of the Korean Society of Automotive Engineers
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• v.17 no.5
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• pp.127-132
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• 2009

The transient performance of the passenger diesel engine equipped with the variable geometry turbocharger was simulated using HIL(hardware-in-the-loop) system. The system consists of engine model as software, and the turbocharger test bench as hardware. The engine model is mean value model which is programmed by the Simulink of the Mathworks. The turbocharger test bench is composed of a blower, some sensors, and DAQ boards. A real time simulation is possible since the operating system based on the real time is included. The results show the good response for the transient characteristics. Therefore this HIL system can be used for development of the new turbocharger effectively.

• The KSFM Journal of Fluid Machinery
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• v.17 no.6
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• pp.13-20
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• 2014

It is necessary to design a compressor with high pressure ratio that satisfies the IMO(international maritime organization) NOx emission regulation for the marine diesel engine. Impeller was designed using the modified slip factor with the flow coefficient. The main purpose of this study is to investigate the sensitivity of the compressor performance by the vaned diffuser geometries. The first vaned diffuser type was based on a NACA airfoil, the second was channel diffuser, and the third was conformally transformated configuration of a NACA65(4A10)06 airfoil. The sensitivity of the performance was calculated using a commercial CFD program for three different diffuser geometries. The channel diffuser showed the wide range of operation and higher pressure characteristics, comparing with the others. This is attributed to the flow stability at diffuser. Combined with this results with impeller design, the optimized compressor was designed and verified by the test results.

• Journal of Advanced Navigation Technology
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• v.14 no.1
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• pp.93-101
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• 2010

In this study, the performance characteristics of turbocharged engine is analyzed. The methods of engine performance improvements are suggested not only for full load characteristics of the engine but also for partial load characteristics of the engine, which is more frequently used in actual driving conditions. The compression ratio of the compressor is increased rapidly in a straight line pattern until 1260 engine rpm, and after that it is increased slowly to 2.5 ratio. Also the brake mean effective pressure increased until 1260 engine rpm and decreased rapidly after 1600 engine rpm. The higher the pressure ratio, the better the fuel consumption, air excess ratio and brake mean effective pressure. But those are higher in the rated revolution range than in the mid-low revolution range. The turbocharger is operated in a stable condition from 1260 rpm and its efficiency is low in the low speed range for the reason of its characteristics. The results of this study can be applied in the fundamental control methods of turbocharged engine for stable load and speed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.11
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• pp.4137-4144
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• 2010

In this study, the simulations were carried out to show the effect of the EGR configuration in a passenger diesel engine with 2-stage turbocharger on the EGR rate. The AMESim and IFP Engine Library were used to make the program for the simulation. Three EGR configurations, HPL(high pressure loop), LPL(low pressure loop), and SLPL(semi low pressure loop), were considered. The EGR rate in the HPL and LPL EGR routes were 6.4% and 10.0% respectively but the rate in SLPL route was 18.0% and their air/fuel ratio for all three cases was 21. Therefore the SLPL EGR configuration may be positively considered in the design of the passenger diesel engine with 2-stage turbocharger.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.11
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• pp.4745-4750
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• 2011

A HIL(hardware-in-the-loop) system was established and the simulation was carried out to determine whether the system operates normally. The system consists of turbocharger test bench, HIL platform with real time S/W and DAQ, and engine model using Matlab/Simulink. In the simulation the supplied fuel rate is changed step-by-step from 1.8944 kg/h to 4.7360 kg/h. The change of air-fuel ratio is analyzed and observed whether the air-fuel ratio follow the target air-fuel ratio 32. When the supplied fuel rate is changed, the air-fuel ratio is converged to the target air-fuel ratio after about 20 seconds. And the vane duty ratio of turbine and the boost pressure of compressor are also changed properly. Therefore this HIL system can be used to develop the new turbocharger and improve the performance of the modified turbocharger.

• Transactions of the Korean Society of Automotive Engineers
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• v.24 no.3
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• pp.319-329
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• 2016

Globally, many researchers have been trying to improve the fuel economy of a vehicle for satisfying future $CO_2$ regulation and minimizing air pollution problem. For the same background, diesel engine and vehicle system optimization using simulation models have been key technologies for the improvement of vehicle system efficiency. Therefore, in this study, calibration method for the air breathing system of a WGT diesel engine using mean value model has been composed for efficient engine and vehicle optimization simulation researches. And virtual WGT performances have been calculated for a 2 cylinder downsized diesel engine system. From these researches, the calibration method for the boost pressure and EGR rate of a virtual diesel engine related with WGT performances could be composed and some of technical issue related with downsized diesel engine could be investigated.