• Journal of the Korean Society of Manufacturing Process Engineers
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• v.2 no.4
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• pp.46-52
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• 2003

For position control of electro-hydraulic servo system, single rod cylinders and double rod cylinders are used. Single rod cylinders have simple structure for manufacturing but different volume ratio of two sides induce to non-linearity in process of then mathematical modeling. So only with conventional PID control method it is difficult to control single rod cylinders precisely. For mole precise position control of single rod cylinders, a controller which is inserted a velocity feedback PID controller and MRAC controller are proposed. With experiment control performances of three control methods are compared. In case of experiment, for external varying load to the system, a hydraulic cylinder and a pressure control valve are used. In conclusion a MRAC is considered a suitable control method for external varying load.

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.8
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• pp.76-82
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• 1999

The object of this study is to find new evalution index for in-cylinder flow characteristics insteady of current swirl, tumble coefficient using steady flow test rig on intake port system. To this end, port flow rig test was conducted on DOHC head varying intake valve lift respectively. Finally combination angular coefficient and inclination angle were introduced as new evaluation index for in-cylinder angular flow characteristics.

• Journal of the korean Society of Automotive Engineers
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• v.10 no.6
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• pp.85-91
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• 1988

The purpose of this study is to investigate the flow through the intake and exhaust system of a spark ignition engine. The flow was assumed to be one-dimensional, compressible and unsteady, and carburetor, muffler, valve and junction are modelled as boundary conditions according to their flow characteristics. In the experiment, four cylinder gasoline engine is used and the pressures in the intake and exhaust pipes and in the cylinder are measured and compared with the results of numerical analysis. In consequence of the comparison, four periods of pressure wave in a cycle are observed in both case of experiment and prediction. In case of exhaust pipe, the results obtained from the experiment are in accord with that from calculation. The results of the intake system show some differences with each other due to the complication in shape, but the periods of both case concur well.

• Transactions of the Korean Society of Automotive Engineers
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• v.2 no.5
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• pp.66-73
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• 1994

The configuration effects of a tumble adaptor which transforms tumble into swirl on the intake tumble characterization under steady flow condition have been investigated by LDV measurement The following parameters were involved to test their effects on tumble-swirl conversion characteristics ; the cylinder height and its bottom shape, measuring position in the swirl induction pipe, and the relative direction of the induction pipe. The short cylinder height and the flat bottom of the tumble adaptor were found effective for the generation of tumble in the cylinder, allowing higher tumble-swirl conversion efficiency.

• Journal of Advanced Marine Engineering and Technology
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• v.23 no.5
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• pp.662-670
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• 1999

A numerical prediction was performed to clarify the air motion in the cylinder of an axisymmet-ric four-stroke reciprocating engine at its intake and compression stage. A scheme of finite volume method is used for the calculation. Modified $k-{\varepsilon}$ turbulence model is adopted and wall function is applied to the grids near the wall. The predicted mean velocity and rms velocity profiles showed a reasonable agreement with an available experimental data at its intake and compression stage. The predicted in-cylinder flow fields show that a strong turbulent twin vortex structure is pro-duced during induction but it commences to decay rapidly around inlet valve closure. The mean velocity continues to fall to a low level during compression but the turbulence intensity attains an approximate constant level.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2001.05a
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• pp.75-90
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• 2001

For the purpose of helping development of a GDI(Gasoline Direct Injection) engine, the in-cylinder phenomena, such as the spray behaviors and fuel distributions, unburned fuel, and flame characteristics were investigated in a single cylinder GDI engine. The GDI engine was equipped with a swirl type electronic injector and SCV(Swirl Control Valve). PLIF(Planar Laser Induced Fluorescence) system with KrF Excimer laser was used for the measurements of the fuel distributions. The effects of the injector specifications, such as the spray cone angle and the offset angle on the fuel distributions and combustion characteristics were investigated. As a result, it was found that the injected fuel spray collided with the bottom of the bowl and moved upward along the exhaust side wall of the piston bowl. This fuel vapor played a important role in the instance of spark ignition. The injector specifications has a great influence on the flame characteristics.

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.7
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• pp.24-31
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• 1999

The MPI engine becomes increasingly popular because it meets two requirements of stringent pollutant emission and the lower fuel consumption. Even though supplies the same amount of fuel to each cylinder , it is hard to precisely control the air-duel ration due to the different amount of air flowing into each cylinder. The uniformity of air-fuel ration in each cylinder is considerably affected by the plenum chamber configuration . This study is focused on experimentally analyzing the flow characteristics within the plenum chamber In the present experiment , steady and valve dynamic state flow tests are performed and the flow field inside the plenum chamber is visualized and measured by utilizing a laser sheet visualization technique and a PTV method. These measured results indicate that the flow structure in the plenum chamber is highly influenced by the plenum chamber configurations, suction flow rates, crank speeds and so on.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.4
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• pp.52-57
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• 2003

Common rail injection system is flexible in injection timing, injection duration and pressure in engine. Many researches have reported on the merits in the application of common rail systems. This research investigated on characteristics and performance for single cylinder diesel engine with a common .ail injection system by varying major parameters such as injection timing, injection duration and common rail pressure. The injection timing and injection duration were controlled by electronic pulse generated. and common rail pressure were controlled by PCV driver. The 498cc single cylinder diesel engine was used in this experiment. All data for combustion pressure, injection timing and injection duration were recorded by Labview. Furthermore, this test was focused on how to optimize injection conditions.

• Journal of the korean Society of Automotive Engineers
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• v.9 no.3
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• pp.85-93
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• 1987

The intake system of 4-cycle, 4-cylinder reciprocating engine is investigated the simple model composed of vessel, duct and throttling part. The numerical calculation based on the simulation is performed for the flow phenomena including heat transfer, friction and bend of duct at each part. In the multi-cylinder engine, the volumetric efficiency is increased a little as the junction location is closed to cylinder at the engine speed having maximum volumetric efficiency. The configuration and dimension of intake system have an influence on the inertia effect by resistance and pressure variation, and the magnitude of that is varied by the engine speed. Thus the volumetric efficiency is correlative to them. The volumetric efficiency is high as the intake valve close is advanced at the low engine speed, and is delayed at high speed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1996.10a
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• pp.77-83
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• 1996

Noise control process of an air intake system for a four-cylinder automotive engine is described. The objective of the process is reduction of induction noise without losing engine performance and changing package layout. The theory and feasibility for noise control elements are also discussed. In general, four-cylinder engines generate a lower frequency induction noise around 80-150 Hz (2400-4500 rpm) and firing frequency, valve impact noise are the main sources. In this paper, the most problematic noise source is identified first and better position of air inlet is selected between inside-fender and out-of-fender layouts. Secondly, the possible noise control approach and CAE analysis results are compared to those from speaker excitation tests. Finally, the effect of the controlled intake system after the installation to an automobile is presented.