• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.27 no.8
• /
• pp.1071-1080
• /
• 2003

A national standard system was developed in order to calibrate and test the oil flowmeters for the petroleum field. A stop valve and a gyroscopic weighing scale were employed for the primary standard of the flow quantity. It is operated by the standing start and finish mode and the static weighing method. The model equation for uncertainty evaluation was based on the calibration principle of standard system. The sources of the uncertainties were quantified and combined according to the GUM(Guide to the Expression of Uncertainty in Measurement). It was found that the standard system had the relative expanded uncertainty of 0.04 % in the range of 18 - 350 ㎥/ｈ. According to the uncertainty budget, the uncertainties of the fluid density and the volume of pipeline, which were temperature dependent, contributed 92% of final uncertainty in the oil flow standard system.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.30 no.5 s.248
• /
• pp.457-464
• /
• 2006

Controlled auto ignition (CAI) combustion, also known as HCCI (homogeneous charge compression ignition), offers the potential to simultaneously improve fuel economy and reduce emission. CAI-combustion was achieved in a single cylinder gasoline DI engine, with a cylinder running in a CAI mode. Standard components were used the camshafts which had been modified in order to restrict the gas exchange process. The effects of air-fuel ratio, residual EGR rate and injection timing such as early injection and late injection on the attainable CAI combustion region were investigated. The effect that injection timings on factor such as start of combustion, combustion duration and heat release rate was also investigated. From results early injection caused the mixture to ignite earlier and burn more quickly due to the exothermic reaction during the recompression and gave rise to good mixing of the fuel-air.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.23 no.1
• /
• pp.97-104
• /
• 2015

This study is a part of the high pressure injection system development on the Turbo GDI engine in order to reduce smoke emission in case of using the low volatile(high DI) fuel which is used as normal gasoline fuel in the US market. Firstly, theoretical approach was done regarding gasoline fuel property, performance, definition of particle matters and its creation as well as problems of the high DI fuel. In this experimental study, 2L Turbo GDI engine was selected and optimized system parameter was inspected by changing fuel, fuel injection mode (single/multiple), fuel pressure, distance between injector tip and combustion chamber, start of injection, intake valve timing in engine dyno at all engine speed range with full load. In case of normal gasoline fuel, opacity was contained within 2% in all conditions. On the other hands, in case of low volatile fuel (high DI fuel), it was confirmed that the opacity was rapidly increased above 5,000 rpm at 14.5 ~ 20 MPa of fuel pressure and there were almost no differences on the opacity(smoke) between 17 MPa and 20 MPa fuel pressure. According to the SOI retard, smoke decrease tendency was observed but intake valve close timing change has almost no impact on the smoke level in this area. Consequently, smoke decrease was observed and 16% at 6000rpm respectively with injector washer ring installed. By removing injector washer to make injector tip closer to the combustion chamber, smoke decrease was observed by 46% at 5,500 rpm, 42% at 6,000 rpm. It is assumed that the fuel injection interaction with cylinder head, piston head, intake and exhaust valve is reduced so that impingement is reduced in local area.

• Transactions of the Korean hydrogen and new energy society
• /
• v.25 no.5
• /
• pp.516-524
• /
• 2014

Proper discharge of nitrogen gas and water condensate is required in a conventional fuel cell system for performance, stability and durability of fuel cell stacks. Present study covers the development of integrated unit and its functioning logic for simultaneous nitrogen gas purge and water condensate drainage in a fuel cell vehicle system. Configuration of condensate drainage pipe, purge valve and level sensor is considered and optimized in physical integration. As a key factor, discharge time is considered and optimized based on the test result of constant-current operation with various operating temperature in logic development. Consequently, derived optimal values are applied and verified in actual vehicle drive mode test. Increase of system design flexibility, weight reduction and cost reduction are anticipated with this study. Additional study for physical and logical improvement is currently being implemented.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.8 no.3
• /
• pp.439-445
• /
• 2013

This study is on the system that can integrate generator and charger to use as a welder and generator for need. Specifically, it was hybrid generator consisted with select switch to use generator controller and multiple function welder, that function were auto-stopping generator when generator power finish to recharge in recharger battery and Co2 MMA TIG MIG MAG are devide depend on supplying gas. This control system of voltage, high-frequency, motor and gas valve was implemented in order to improve the performance and convenience of existing welders to choose only one or two at a time.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.13 no.11
• /
• pp.5409-5415
• /
• 2012

Piezo ceramic actuator is used for various industrial products such as spray, dispenser, and valve control etc. Since the deflection of the piezo ceramic element depends on the applied voltage, it is required a power amplifier with high voltage supply for driving the piezo ceramic actuators. In this paper, we develop a simple H-bridge type power amplifier and a compact flyback type high voltage switching mode power supply for piezo ceramic actuators. It is easy to adjust the amount of energy input to piezo ceramic actuator by pulse-width-modulation with H-bridge type power amplifier.

• Journal of Biosystems Engineering
• /
• v.12 no.1
• /
• pp.6-13
• /
• 1987

A mathematical model for the waste heat recovery system for an engine was developed. The model based on the experimental data reported before was validated and was used to predict the waste heat recovery and recoverable heat of the engine at various operating conditions of the engine and the system. The model was also used to determine flow rates of the circulating water in the system for a certain temperature increment of the water at various operating conditions of the engine to give basic data to design the system. Stability of the system performance was tested on subjects of vapor lock problem, thermal characteristics of the thermostatic valve, and temperature variation of the circulating water in the engine and fuel consumption of the engine during each mode of the system operation and its change into the other. The test showed that the system operation was stable enough. Temperature profile in the thermal energy storage (TES) was observed during storing thermal energy, and thermal stratification in the TES was well formed acceptable to be used in the system. Finally a scheme to automatize the system was suggested.

• Journal of Drive and Control
• /
• v.14 no.4
• /
• pp.29-36
• /
• 2017

Electronic control technologies that have long been developed for passenger cars spread to construction equipment and agricultural vehicles because of its outstanding performance achieved by embedded software. Especially, system program of transmission control unit (TCU) plays a crucial role for the superb shift quality, driving performance and fuel efficiency, etc. Since the control algorithm is embedded in software that is rarely analyzed, development of such a TCU cannot be conducted by conventional reverse engineering. Transmission simulator is a kind of electronic device that simulates the electric signals including driver operation command and output of various sensors installed in transmission. Standalone TCU can be run in normal operation mode with the signals provided by transmission simulator. In this research, transmission simulator for the tracked vehicle TCU is developed for the analysis of shift control algorithm from the experiments with standalone TCU. It was confirmed that shift experimental data for the simulator setup conditions can be used for the analysis of control algorithms on proportional solenoid valves and shift map.

• Transactions of the Korean hydrogen and new energy society
• /
• v.26 no.2
• /
• pp.136-147
• /
• 2015

Dead-ended operation of Proton Exchange Membrane Fuel Cell(PEMFC) provides the simplification of fuel cell systems to reduce fuel consumption and weight of fuel cell. However, the water accumulation within the channel prohibits a uniform supply of fuel. Optimization of the purge strategy is required to increase the fuel cell efficiency since fuel and water are removed during the purge process. In this study, we investigated the average voltage output which depends on two interrelated conditions, namely, the supply gas pressure, purging valve open time. In addition, flow visualization was performed to better understand the water build-up on the anode side and cathode side of PEMFC in terms of a variety of the current density. We analyzed the correlation between the purge condition and water flooding.

• Proceedings of the KSME Conference
• /
• 2008.11b
• /
• pp.3102-3107
• /
• 2008

This paper was focused on the particulate matter (PM) on the gasoline and bio ethanol. Bio ethanol as a clean fuel is considered one of the alternative fuels that decreased the PM emission from the vehicle. Particle formation in SI engine was depended on the fuel and engine operating condition. In this paper, Particle number concentration behaviors were analyzed by DMS500 (Differential Mobility Spectrometer) and CPC (Condensation Particle Counter) instrument which was recommended by PMP (Particle Measurement Programme). Particle emissions were measured with various engine operating variables such as air excess ratio ($\lambda$), spark timing and intake valve opening (IVO) at part load condition. In vehicle test, the number of particulate matter was analyzed with golden particle measurement system, which was consist of CVS (Constant Volume Sampler), particle number counter and particle number diluter.