• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.4
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• pp.26-33
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• 2000

In-cylinde flow and mixture formation are key contributors to both idle stability and combustion stability at part load condition in SI engine. The real time measurements of air-fuel ration and in- cylinder residual gas fraction are particularly important to obtain a better understanding of the mechanisms for combustion and emissions especially during cold start and throttle transient condition. This paper reports the cycle resolved measurements of residual gas fraction and equivalence ration near speak plug with value timing change and their effects on combustion characteristics at part load. The results showed that the effect of intake value opening on the residual gas fraction was smaller than that of exhaust valve closing because of the decreases of exhaust gas reverse flow from exhaust port. The variation of equivalence ratio near spark plug increased with the increase of value overlap and it closely related with heat release rate and combustion stability

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.899-903
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• 2004

A limit switch box is used for a indicator of a valve actuator. This device indicates an opening and closing of a valve or throttle in a valve actuator. In ship, equipments are required safe and robust because of a rough environment and a specific condition during a voyage. However, the limit switch box is used in an indoor environment generally. Thus, a new limit switch box must be developed which can be used at an outdoor environment. This study designed the limit switch box. The housing of the limit switch box was made by an aluminium die cast method with surface painting after anodizing or chromate coating. In order to evaluate the endurance of the housing, the endurance tests against salt water have been conducted. Experiment results showed that the proposed device provides a reliable performance against salt water.

• Transactions of the Korean Society of Automotive Engineers
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• v.18 no.5
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• pp.62-67
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• 2010

Exhausting fossil fuel and increasing concern of air pollution have brought on the change of the focus of developing new vehicles from performance to fuel economy and emission. The gasoline engines adopting the naturally aspirated way use the throttle-body for engine load control. Therefore, its pumping loss increases more than that of the diesel engine, and also mostly operating in a partial load condition has bad influence on fuel economy and emission. In these days, the continuous variable valve timing system and variable induction system are adopted in order to improve fuel consumption and emission. In this study, we optimize the runner length and operate region of variable induction system to simulataneously improve the performance, fuel economy, and emission of gasoline engine with employing GT-Power as a CAE tool for engine analysis and PIAnO as PIDO tool for process integration and design optimization.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.4
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• pp.153-158
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• 2013

The purpose of this study is to investigate the performance characteristics of the counterflow exhaust heat recovery device for the applied gasoline engines. The EHRS device is installed behind the catalyst. This study investigates the engine warm-up characteristic, the exhaust noise characteristic, the back-pressure characteristic. The engine warm-up characteristics is (load 0%, load 10%, load 20%) in (idle, 1000rpm, 1500rpm, 2000rpm, 2500rpm) conditions by measuring the time it warmed up, coolant temperature ($25^{\circ}C{\sim}80^{\circ}C$) until the performance evaluation is performed. The wide open throttle and the coast down the exhaust noise and the back-pressure characteristic experiment repeated twice. The test conditions is 950rpm~6,050rpm proceed experiment repeated 3-5 times. Load 0% idle conditions except the results improved engine warm-up characteristics. The exhaust noise obtain similar results the BASE+EHRS W/O_FRT_MUFF with BASE and back-pressure to obtain similar results BASE+EHRS W/O_FRT_ MUFF with BASE+EHRS.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.2
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• pp.100-106
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• 1998

The wide open throttle performance and piston temperatures were measured by the change of fuel : gasoline and liquefied petroleum gas(LPG). Bench test method was developed and experimented to study the effect of temperature on the formation of carbon deposit. The bench test results were confirmed by measuring the piston temperature and observing the deposit production rate at an actual engine running condition. Results show that if the fuel of spark ignition engine is changed from gasoline to LPG, the output power decreases about 10% and the piston temperatures increase about 40~55$^{\circ}C$. In actual engine tests, because of this temperature increase, it was observed that the quantity of carbon deposit in the top ring groove increased in a big degree. Consuquently, it is known that the fing sticking may occur if the gasoline engine was rebuilt to LPG fuelled engine. Therefore, in order to preserve the durability of LPG fuelled engine, it is necessary to lower the piston temperature by hardware modificationor to reduce the carbon deposit by the improvement of engine oil.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.6
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• pp.21-29
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• 2003

Boosting of engine power by using Turbo- or Super-charger is a solution to comply with $CO_2$-regulation in Europe. Turbo-charger is now playing a major role in the field of charging system thank to its technical advantages such as no demand of operation power from engine. A mechanically driven Super-charger, however, is now popular due to quick speed response to change of the driving mode-high engine torque even at low engine speed. Since Super-charger needs operation power from engine, it is difficult to improve its relatively higher fuel consumption than that of Turbo-charger. This negative point is still an obstacle to the wide use of Super-charger. This study aims to develop power control concept to achieve the minimization of operation power when it is not necessary to charge at idling or part load driving condition. A screw type Super-charger was modified in design partially and adapted an internal bypass valve and a bypass tube to control charging pressure at part load. The various control concepts show a possibility to reduce operation power of Super-charger and result in improvement of fuel consumption.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.836-839
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• 2005

A limit switch box is used for a indicator of a valve actuator. This device indicates an opening and closing of a valve or throttle in a valve actuator. In a ship, equipments are required safety and robustness because of a rough environment and a specific condition during a voyage. However, the limit switch box is used in an indoor environment generally. In order to evaluate the endurance of the limit switch box used in an indoor environment, the endurance tests against salt water have been conducted. Experiment results showed that the limit switch box was corroded severely. Thus, this study developed a new limit switch box which can be used at an outdoor environment. The housing of the developed limit switch box was made by an stainless steel to prevent corrosion.

• Journal of Korean Institute of Industrial Engineers
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• v.25 no.1
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• pp.100-110
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• 1999

The objectives of this study are twofold: (1) to evaluate the cockpit of three Korean air force fighters such as F-4, F-5, and F-16 in an ergonomic perspective and (2) to measure the musculoskeletal discomfort of the fighter pilots. For the study, 369 air force pilots from 7 squadrons were surveyed. The study shows that the cockpit design of F-16 is superior to the others. However, F-4 is the worst among them. Statistical analyses reveal that the seat in the cockpit raised the most complaints, regardless of types of fighter planes. The main problems with the seat included inappropriate designs of the backrest angle, seat cushioning, and parachute harness. Also frequently cited are various control switches, control stick, rudder pedal, and the throttle. That these items lack human integration is found in remote positions and improper dimensions. The implications of these findings are discussed. The self-reported musculoskeletal complaints show that the main discomfort is on the back and neck. Also, the buttocks, shoulders, and the legs/knees are common sites of discomfort. A stepwise regression analysis shows that the back discomfort, is mainly caused by the use of the seat, rudder pedal, control stick, and switches. A Spearman rank correlation coefficient test also reveals that job dissatisfaction of the pilots is related to the complaints with the cockpit and musculoskeletal discomfort. These findings suggest that more comprehensive studies for cockpit design in the aspects of functional anthropometry of Korean pilots are needed to reduce the musculoskeletal discomfort.

• Journal of Power System Engineering
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• v.19 no.2
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• pp.40-48
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• 2015

As advantages of LPG-DI engine, LPG is directly injected into combustion chamber during compression stroke to reduce compression temperature, prevent knock and spontaneous combustion, and adjust engine output using the amount of directly injected fuel, thereby reducing pumping loss caused by throttle valve. Stratified charge can be supplied nearby spark plugs to allow for overall lean combustion, which improves thermal efficiency and can cope with problems regarding emission regulations. In addition, it is characterized by free designing of intake manifold. Despite the fact that LPG-DI has many advantages as described above, there is lack of detailed investigation and study on spray characteristics, combustion flame characteristics, and ignition probability. In this study, a visualization experiment system that consists of visualization combustion chamber, air supply control system, emission control system, LPG fuel supply system, electronic control system and image data acquisition system was designed and manufactured. For supply of stratified charge in the combustion chamber, alignment of injector and spark plugs was made linear.

• Journal of the Korean Institute of Gas
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• v.4 no.2 s.10
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• pp.20-26
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• 2000

In this experimental study, we examined gas engine characteristics of a small high-speed engine in various ways. And we studied performance of natural gas, hydrogen gas and gasoline fuel engines, as emission characteristics and process of combustion. For the purpose of preventing back-fire occurred in case of high-speed and high load in hydrogen engine, we controlled air quantity by installing throttle valve in gas fuel engine. We performed experiment by mixing nitrogen to hydrogen fuel. As a result, we could find out characteristics which of a high speed small engine by applying gas fuels.