• Journal of Biosystems Engineering
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• v.27 no.1
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• pp.33-38
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• 2002

The indicated power of Stirling engine was affected by the heat exchange effectiveness of the regenerator. The temperature difference of working fluid between the expansion and the compression space of Stilting engine depends on the heat exchange effectiveness of the regenerator. The influence of the temperature ratio of expansion space to compression space of Stirling engine on the indicated power was analyzed by using Schmidt analysis in this study. In the Stirring engine, as the temperature ratio increased, the indicated power generally decreased. Therefor, it is necessary to develope the regenerator of high effectiveness. The actual indicated power was shown 64.9 percent of the predicted indicated power in maximum and 47.2 percent of that in minimum due to increased dead volume of engine, the loss of flow friction and heat transfer in the regenerator.

• Journal of the Korean Society of Propulsion Engineers
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• v.12 no.4
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• pp.42-47
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• 2008

The power control system of Smart UAV is similar to the propeller pitch governing concept of turboprop aircraft. The pilot adjusts the engine power directly and the pitch governor controls the propeller pitch to maintain the propeller rotational speed. The electronic engine controller(EEC) of PW206C engine developed for helicopter is not fit for the power control concept of Smart UAV, and therefore the manual back-up system of PW206C engine is used for the engine power control of Smart UAV. Engine performance estimation program is used to predict the control range of power lever angle(PLA) according to the variation of engine output shaft speed, flight altitude and flight speed. These data provide a guide for the PLA control in manual mode operation.

• Transactions of the Korean Society of Automotive Engineers
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• v.1 no.2
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• pp.49-59
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• 1993

A new signal processing technique is applied to four-cylinder spark and compression ignition engines for the diagnosis of power faults inside the cylinders. This technique utilizes two-sided directional power spectra(예S) of complex vibration signals measured from engine blocks as the patterns for engine cylinder power faults. The dPSs feature that they give not only the frequency contents but also the directivity of the engine block motion. For the automatic detection/diagnosis of cylinder power faults, pattern recognition method using multi-layer neural networks is employed. Experimental results show that the sucess rate for diagnosis of cylinder power faults using dPSs is higher than that using the conventional one-sided power spectra. The proposed technique is also tested to check the robustness to the sensor position and the engine rotational speed.

• Tribology and Lubricants
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• v.21 no.6
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• pp.249-255
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• 2005

In this paper, the friction characteristic of engine bearings has been analyzed in terms of a friction loss power, a minimum film thickness and an oil film pressure. This analysis has been focused on the fuel economy improvement with a low viscosity engine oil such as SAE 0W-40, which is used for a friction loss reduction and increased for a Diesel fuel economy. The friction loss power, the minimum oil film thickness and oil film pressure distribution for plain bearings of a Diesel engine are analyzed using an AVL's EXCITE program with a conventional engine oils of SAE 5W-40 and 10W-40, and a low viscosity engine oil of SAE 0W-40. The computed results indicate that a viscosity of engine oils is closely related to the friction loss power and the decreased minimum film thickness in which is a key parameter of a load carrying capacity of an oil film pressure distribution. When the low viscosity engine oil is supplied to engine bearings, it does not affect to the formation of a minimum oil film thickness. But the friction loss power has been significantly affected by low viscosity engine oil at a low operating temperature of 0. Based on the FEM computed results, the low viscosity engine oil at a low temperature range will be an important factor for an improvement of the fuel economy improvement.

• Proceedings of the KSME Conference
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• 2001.11b
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• pp.353-358
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• 2001

Turbo-charging or Super-charging has been used to boost engine power for Gasoline Engine and Diesel Engine came to the world at the beginning of $20^{th}$ century. So far Turbo-Charger has enjoyed a high reputation in the charging filed for its technical advantages such as no demand of operation power from engine and an excellent charging effect in the event of a static operation at mid- and high engine speed. A mechanically driven Super-Charger, however, is now emerging in order to meet demands of the age of speed such as high engine power for a quick change of the driving mode - high engine torque even at low engine speed. Since Super-Charger needs driving power from engine, it cannot improve its relatively higher fuel consumption against that of Turbo-Charger. This negative point is still an obstacle to the wide use of Super-Charger. Super-Charger using Screw-type compressor which has already had a considerable base in air compressor market will fulfill this purpose of improving fuel consumption by minimizing operation power owing to no charging at idling or partially loading driving. This study aims to develop power control concept to achieve this minimization of operation power.

• Journal of the Korea Institute of Military Science and Technology
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• v.25 no.5
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• pp.539-544
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• 2022

This research shows the test performance of a 6 kW-scale hybrid electric power system for the high endurance drone. The power system is composed of a two-stroke reciprocal engine, starter-generator and battery, and they are integrated as one power unit. The engine is designed to provide the house for holding the starter-generator at the end of a crankshaft in turn the engine and starter-generator can maintain the same speed during the operational period. In this way, the generated power is readily controlled by just manipulating an engine throttle movement. Moreover, the starter-generator can initiate an engine operation with an aid of battery power until the combustion process becomes stabilized. In consequence, integration mechanism between an engine and generator is simplified, which results in weight reduction achieved. The duty of back-up battery is to provide a starting power to generator via a system controller in addition to covering momentarily power shortage. Therefore, the electric power system is vindicated to provide 6 kW power through a ground test.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.11a
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• pp.339-342
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• 2007

The power control system of Smart UAV is similar to the propeller pitch governing concept of turboprop aircraft. The pilot inputs the engine power directly and the pitch governor controls the propeller pitch to maintain the propeller RPM. The manual back-up system of PW206C engine is used for the engine power control of Smart UAV. Engine performance estimation program is used to predict the control range of power lever arm(PLA) angle according to the variation of flight altitude and speed. These data provide a guide for the engine control in manual mode operation.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.10
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• pp.1427-1434
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• 2003

Turbo- or Super-charging has been used to boost engine power for Gasoline- and Diesel Engine since beginning of 20th century. So far turbo-charger has enjoyed a high reputation in the charging field for its technical advantages such as no demand of operation power from engine and an excellent charging effect in a static operation at mid- and high engine speed. A mechanically driven super-charger, however, is now popular due to the high engine power at quick 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 supercharger. Super-charger using screw-type compressor will fulfill the purpose to reduce fuel consumption by minimizing operation power owing to no charge at idling or part load driving condition. This study aims to develop power control concept to achieve the minimization of operation power. A screw type super-charger was modified in design partially and installed with 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.

• Journal of Power System Engineering
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• v.19 no.5
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• pp.67-72
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• 2015

The reliable operation of onsite emergency diesel generator(EDG) should be ensured by a conditioning monitoring system designed to maintain, monitor and forecast the reliability level of diesel generator. The purpose of this paper is to develop condition diagnosis algorithm(logic) and analysis program of engine for the accurate diagnosis in actual condition of emergency diesel generator engine. As a result of this study, we confirmed that developed engine condition diagnosis algorithm and analysis program could be efficiently applied for actual EDG engine in nuclear power plant.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.2
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• pp.580-590
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• 1995

To design and develop a turbocharged engine, ti needs that many study must be preceded about the characteristics of engine performance. Especially, a basic data about deciding target power is urgently needed for which is practically useful for engine design. The power output of turbo-charged engine is dominated by engine speed, displacement, compression ratio, air fuel ratio and charge pressure ratio. Therefore, the independent effect of these factors on power output was clarified from experiment, and the experimental equation to predict the power was founded from there results. The predicted power output from the experimental equation was well coincided with power measured through experiment.