• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.10
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• pp.5980-5987
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• 2014

As a response to exhaust gas regulations, the electronic control system was applied to the diesel engine. The injected fuel mass and injection timing are accurately controlled using it, and the fuel efficiency and the engine output are significantly increased. In addition, the noise and the vibration of vehicles are decreased. To maintain the optimal performance of an electronic control diesel engine, it is important to control the fuel injection pressure accurately using the fuel pressure regulator. When the fuel pressure regulator is not worked normally, the failure phenomena (starting failure, staring delay, accelerated failure, engine mismatch et al.) occurred because the fuel pressure is not stabilized and controlled accurately. In this study, the effects on a fuel pressure, return fuel mass flow, and engine rotating speed according to the control rate of fuel pressure regulator were investigated to analyze the performance variation under the failure conditions of a fuel pressure regulator. As a result, when the control rate of a fuel pressure regulator decreased by 4%~6% compared to that of the standard condition, the variation of engine rotating speed and return fuel flow were increased greatly, and the abnormal condition occurred. In addition, it is possible to diagnose the failure of a fuel pressure regulator by monitoring these conditions.

• International Journal of Automotive Technology
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• v.4 no.1
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• pp.41-45
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• 2003

The 42V Mild Hybrid System has been released into market by Toyota for the first time in the world in 2001. The set-up employs an inverter unit to control the motor/generator (MG) electronically. The driving system called such as Toyota Mild Hybrid System (TMHS) has additional new functions to conventional internal combustion engines. When stopping vehicle, the engine stops promptly. When starting vehicle, by releasing the brake pedal MG starts the vehicle at the same time (EV-driving mode). When stepping on the accelerator pedal, or after a given period of time the engine firing occurs and the engine-driving mode starts. When running by motor, the power is supplied to the motor from 36V battery through the inverter. High outputs and instant responses are required for Inverter. At the same time, the compact volume is required to fit into the limited space of the engine room. The compact size and high output are also required to Power Capacitor used for this inverter. The power capacitors has been newly developed, shaped in "flat" type, suitably for the inverter. The points of developments on inverter and power capacitor are described in this paper.his paper.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.11a
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• pp.75-81
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• 2006

The propulsion system of KSLV-I second stage is engine with high expansion ratio and its starting altitude is high. To verify the performance of engine before the launch in the ground, high altitude test facility to simulate its operating condition is necessary. This material is about the concept design of high altitude simulation test facility for second stage engine. And it will be the basis for the construction of test facility and the test of engine.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.3
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• pp.35-40
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• 2012

The 3/2-way valve supplies the high pressure air to ship engine for starting engine. In this paper, the high pressure 3/2 way valve for ship engine has the goal as reverse engineering by searching the fluid characteristic at this valve. The reverse engineering of 3/2-way valve is measured directly by Verier-calipers and is compared with 3D scanner. The fluid characteristic in this valve is used for a simulation method by ANSYS CFX 12.1. On the contrary, discs and the shaft are as the important components on numerical simulation by controlling the air flow at this valve. The fluid characteristics are seen to make high velocity and complicated vortex around the shaft. And the flow coefficient is calculated in order to apply for industrial field.

• Journal of ILASS-Korea
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• v.16 no.3
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• pp.146-151
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• 2011

LPG(Liquified Petroleum Gas) fuel for vehicles has lots of advantages such as low emission level, cheaper fuel cost and enough infrastructure. Therefore it arouses interest as an alternative engine to reduce emission of diesel engines. Especially MPI(Multi Point Injection) type LPLi(Liquid Phase LPG injection) system could have overcome the disadvantages of mixer types such as low engine performance, decreased charging efficiency and cold starting difficulty. However ice formation on the nozzle tip and intake port due to the freezing of moisture around the components is often observed in LPLi systems. This icing phenomenon is the direct cause of unstable engine combustion, resulting in engine emissions. Therefore in this research, a spray visualization test for LPG injection was carried out to obtain the basic information of an LPLi injector, then the effects of butane and propane mixing rates on ice formation at the intake port and nozzle tip was investigated. As a result, the icing characteristics of them showed contrary results according to the mixing rates.

• Tribology and Lubricants
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• v.35 no.4
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• pp.244-266
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• 2019

The purpose of this study is to estimate the wear volumes of engine journal bearings operating at variable angular velocity of a shaft in the beginning of firing start-up cycle. To do this, first we find the potential region of wear scar on engine journal bearings where the applied bearing load and crank shaft velocity are variable. The potential wear regions are discovered by finding minimum oil film thickness at every crank angle existing below most oil film thickness scaring wear (MOFTSW) obtained based on the concept of the centerline average surface roughness. Then we calculate the wear volume from the wear depth and two wear angles decided by the magnitude of each film thickness lower than MOFTSW at every crank angle. The results show that the expected wear region is located at a few bearing angles after and/or behind the upper center of a big-end bearing and the lower center of a main bearing. And the real wear region is similar to the estimated wear region. Further we find that the wear scar on an engine journal bearing may occur at re-starting time after switch-off of a start motor especially under the condition of high oil temperature.

• Journal of the Korean Society of Propulsion Engineers
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• v.26 no.1
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• pp.77-87
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• 2022

In order to perform the scramejt engine intake ground test using the Scramjet Engine Test Facility(SETF) of the Korea Aerospace Research Institute. we introduced the test availability check procedure that is generally conducted. The design process of the newly manufactured Mach 5 nozzle for the scramjet intake test was summarized, a device for checking the core flow distribution of the nozzle was explained, and the core flow test analysis results were written. Through a series of test results, it was confirmed that the intake was located in the new Mach 5 nozzle core.

• Journal of the Korean Society of Propulsion Engineers
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• v.15 no.2
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• pp.23-28
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• 2011

The engine ground and altitude tests were carried out to investigate the effect of jet fuel alteration on the performance of a small turbojet engine. JP-S was supplied 8% higher than JP-8 by fuel metering system at the same command. The employment of JP-S showed the similar starting characteristic to that of JP-8, however, difference in the ignition time and acceleration rate of engine speed due to the difference of fuel flow rate by fuel metering system was observed. In spite of jet fuel alteration, the test results yield the similar steady-state engine performance in net thrust, air flow, exhaust gas temperature, etc. On the other hand, the fuel consumption of JP-S increased by 5 % compared with that of JP-8. In point of specific fuel consumption (SFC), SFC of JP-S was approximately 1.1~2.6 %, 5 % higher than that of JP-8 in ground and altitude tests respectively at the same thrust.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.410-415
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• 2010

The engine ground and altitude tests were carried out to investigate the effect of jet fuel alteration on the performance of a small turbojet engine. JP-S was supplied 8% higher than JP-8 by fuel metering system at the same command. The employment of JP-S showed the similar starting characteristic to that of JP-8, however, difference in the ignition time and acceleration rate of engine speed due to the difference of fuel flow rate by fuel metering system was observed. In spite of jet fuel alteration, the test results yield the similar Steady-State engine performance in Net thrust, Air flow, Exhaust Gas Temperature, etc. On the other hand, the Fuel consumption of JP-S increased by 5 % compared with that of JP-8. In point of Specific Fuel Consumption (SFC), SFC of JP-S was approximately 1.1~2.6 %, 5 % higher than that of JP-8 in ground and altitude tests respectively at the same thrust.

• Journal of Advanced Marine Engineering and Technology
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• v.22 no.1
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• pp.42-51
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• 1998

A 150 m$\^$3//hr, 30 kg/cm$\^$2/, air-cooled 3-stage reciprocating air compressor is designed to be used in starting large diesel engines of ships. A basic design procedure is presented to meet the targeted pressure and flow rate, and especially a volumetric efficiency of 80%. Temperature and stress analysis of the 1st stage cylinder are performed using axisymmetric FEM modelings. The dynamics of valve system is analyzed and stress at the 1st stage valve seat caused by valve impact is evaluated. To reduce friction loss and wear at the compressor engine system tribological design issues are reviewed and good design practices are suggested. Finally, forced-air pin-type interstage coolers are designed to dissipate generated compression heat at each stage.