• 한국추진공학회지
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• 제25권1호
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• pp.68-76
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• 2021

본 연구에서 대상으로 삼은 직렬 하이브리드 시스템은 무인기용으로 왕복엔진, 발전기, 배터리를 주 동력원으로 사용한다. 발전기는 왕복엔진의 구동축에 직결되며, 왕복엔진-발전기 세트의 운용 특성은 지상통합시험을 통해 확인하였다. 본 연구에서는 해당 시험 결과를 바탕으로 왕복엔진-발전기 출력과 배터리 출력을 효율적으로 사용하기 위한 제어로직을 제시하였고, 로직에 따른 왕복엔진-발전기와 배터리의 출력 변동은 시뮬레이션을 통해 확인하였다. 그 결과, 발전기 출력은 제시된 제어로직에 의해 배터리 출력과 함께 추진요구전력을 공급함을 확인하였다.

• Journal of Mechanical Science and Technology
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• 제16권7호
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• pp.942-949
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• 2002

The use of a combined starter/generator integrated into the drive train of an automobile offers several possibilities for improvement of fuel economy The use of such a starter/generator system is made feasible by a switch from a 14 volts electrical system to a 42 volts system, however, the sizing of the components is not a trivial problem. This study combines a dynamic electromechanical model of the starter, battery and power electronics with the nonlinear mechanics of the piston/crankshaft system and a thermofluid model of the compression and expansion processes to investigate the cold start problem. The example involves the start of an eight cylinder engine at -25 degrees Celsius. This paper shows how the mechatronic V8 engine of an automotive starter/generator system for the startability works well.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집B
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• pp.213-219
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• 2000

In this work, it has been predicted the thermal performance of the engine cooling system in cases of stationary mode, constant speed mode, city-drive mode, and hill-climb mode by theoretical modeling of each component and numerical analysis. The modelling components are engine, radiator, heater, thermostat, water-pump, and cooling-fan. And also it has been developed the simulation program that can be used in case of design and system configuration changes. The comparison has not been made to verify the results of this work with experimental data, but the overall tendencies were agreed well with those of actual situation in four modes.

• 한국자동차공학회논문집
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• 제16권5호
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• pp.44-48
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• 2008

This paper describes on studies of the heavy duty engine calibration for better fuel economy based on real driving conditions. Using testbed validated software simulation of the engine and turbocharger system, an alternative turbocharger specification, with potential to improve fuel economy was identified. Secondly, the engine calibration was modified to optimize vehicle fuel economy over a typical customer drive cycle whilst still meeting the steady-state (testbed) emissions legislation. These results were confirmed by field testing of a vehicle equipped with the updated specifications. This study found good agreements between the prediction and the field test on the vehicle fuel economy improvements of the express bus with updated calibration and turbocharger.

• 드라이브 ㆍ 컨트롤
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• 제9권4호
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• pp.42-51
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• 2012

Variable displacement vane-type oil pumps represent one of the most innovative pump types for industrial applications, especially for engine lubrication systems. This paper deals with a modeling method for theoretical flow rate investigation of a typical variable displacement vane-type oil pump. This theoretical model is based on the pump geometric design and dynamic analyses. It can be considered as mandatory steps for a deeper understanding of the pump operation as well as for effectively implementing the pump control mechanisms to satisfy the urgent demands of engine lubrication systems. The developed pump model is finally illustrated by numerical simulations.

• 한국분무공학회지
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• 제9권4호
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• pp.77-82
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• 2004

This paper describes the improvement of engine cooling system. To improve engine cooling performance, the authors approached in two ways. One is to increase water pump performance, changing of impeller shape and lightening of material were carried out. The second one is cooling efficiency rise, which were investigated with head gasket coolant flow passage optimization with flow visualization technique. The test results show that water pump performance was increased effectively, reduction of pump drive torque, and increase of pump flow-rate and pressure rise. Gasket hole pattern optimization test results represent an optimized head coolant flow which stands cross flow from exhaust to intake port side and small vortex were removed.

• 한국항공우주학회지
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• 제44권10호
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• pp.911-920
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• 2016

발사체의 피치 및 요 축 자세제어를 위해 엔진의 연소 중 추력의 방향을 변화시키는 추력벡터제어를 많이 사용한다. 발사체의 추력벡터제어를 위한 구동장치로는 중량 대비 동력 효율이 좋은 유압식 구동장치를 보편적으로 사용하여 왔으나 요즘은 고효율의 전기모터 개발과 모터 제어 기법의 발전으로 상대적으로 규모가 작은 발사체의 추력벡터제어에는 전기기계식 구동장치시스템을 적용하는 연구를 많이 수행하고 있다. 본 논문에서는 한국형발사체 3단 엔진의 추력벡터제어를 위해 개발 중인 직구동 방식의 전기-기계식 구동기의 설계 내용 및 시제품 시험결과를 기술하였다.

• 대한기계학회논문집A
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• 제40권8호
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• pp.759-765
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• 2016

항공기 등에 사용되는 Flexible PTO(Power Take-Off) 샤프트는 스프링 특성을 좋게 하기 위해 여러장의 얇은 멤브레인을 용접한 형태로 1950년대에 이미 개발됐으며, AMAD(Aircraft Mounted Accessory Drive) 기어박스와 EMAD(Engine Mounted Accessary Drive) 기어박스 사이에서 회전동력을 전달한다. 이런 종류의 샤프트는 가볍고 특히 스프링 특성이 좋기 때문에 축 정렬이 틀어진 고속회전 상태에서도 안정적으로 회전동력을 전달할 수 있어 대부분의 전투기에 사용된다. 이번 연구에서 티타늄 합금으로 개발된 Flexible PTO 샤프트의 구조해석을 통해 제품의 안전성을 확인하였고, 실제 실험실에서 진행된 고속회전 시험에서 굽힘과 비틀림 부하를 동시에 인가하여 샤프트의 고주기 피로에 대한 내성을 실증하였다. 또한, 고주기 피로 시험 조건에서 항공기용 볼 조인트의 마모 특성 분석을 통해 수명을 예측하였다.

• 드라이브 ㆍ 컨트롤
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• 제10권2호
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• pp.7-12
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• 2013

In this study, a wire/wireless communication system transmitting the operation data of engine from the ER (Engine Room) to the engine controller of ECR(Engine Control Room) has been developed through the communication of ISM(Industrial Science Medical) Band for the test operation environment improvement of medium speed engine. This wire/wireless communication system is composed of the RTU (Remote Terminal Unit) gathering and transmitting engine data as well as the MCU (Master Control Unit) receiving engine status information from the RTU to be sent to the engine controller (PLC). Through this study, a trial product of RTU and MCU has been manufactured. A test bench that has made temperature, pressure and pick-up sensor into a module for the local test of prototype was produced a test bench. In addition, at the same time save the data to a Web server and the smart phone real-time monitoring system has been developed using Wi-Fi communications. The ultimate objective of this study is to develop a wireless smart phone monitoring system of engine for the operator of engine to be able to monitor and control engine status even from the outside of engine room and control room based on this study.

• 대한기계학회논문집
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• 제19권7호
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• pp.1702-1708
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• 1995

Owing to the serious problem of hydrocarbon fuel such as environmental pollution, the development of alternative fuel is very urgent. To adopt hydrogen to the internal combustion engine, a solenoid-drive type in-cylinder injection system was constructed. The injection system was installed to the single cylinder research engine, and the engine performance and the emission of citric oxide were tested upon the fuel-air equivalence ratio and the spark timing. In the case of in-cylinder injection system, hydrogen is injected after the intake valve is close, so it is possible to operate the engine without the back fire and the fall of its volumetric efficiency. In the region of the fuel-air equivalence ratio below 0.5, hydrogen and air aren't well mixed and the thermal efficiency is lowered, so the nozzle should be designed to inject hydrogen uniformly into the combustion chamber. In the region of the fuel-air equivalence ratio above 0.7,the fuel-air mixture burns very fast and the amount of citric oxide emission increases rapidly, so the spark timing should be retarded as compared with MBT.