• Journal of Biosystems Engineering
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• v.6 no.1
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• pp.28-38
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• 1981

A survey has been conducted to investigate the presents of breaks down and repair of power tiller for efficient use. Eight provinces were covered for this study. The results are summarized as follows. A. Frequency of breaks down. 1) Power tiller was breaken down 9.05 times a year and it represents a break down every 39.1 hours of use. High frequency of breaks down was found from the fuel and ignition system. For only these system, the number of breaks down were 2.02 and it represents 23.3% among total breaks down. It was followed by attachments, cylinder system, and traction device. 2) For the power tiller which was more than six years old, breaks down accured 37.7 hours of use and every 38.6 hours for the power tiller which was purchased in less than 2 years. 3) For the kerosene engine power tiller, breaks down occured every 36.8 hours of use, which is a higher value compared with diesel engine power tiller which break down every 42.8 hours of use. The 8HP kerosene engine power tiller showed higher frequency of break down compared with any other horse power tiller. 4) In October, the lowest frequency of break down was found with the value of once for every 51.5 hours of use, and it was followed by the frequency of break down in June. The more hours of use, the less breaks down was found. E. Repair place 1) 45.3% among total breaks down of power tiller was repaired by the owner, and 54.7% was repaired at repair shop. More power tiller were repaired at repair shop than by owner of power tiller. 2) The older the power tiller is, the higher percentage of repairing at the repair shop was found compared with the repairing by the owner. 3) Higher percentage of repairing by the owner was found for the diesel engine power tiller compared with the kerosene engine power tiller. It was 10 HP power tiller for the kerosene power tiller and 8 HP for the diesel engine power tiller. 4) 66.7% among total breaks down of steering device was repaired by the owner. It was the highest value compared with the percentage of repairing of any other parts of power tiller. The lowest percentage of repairing by owner was found for the attachments to the power tiller with the value of 26.5%. C. Cause of break down 1) Among the total breaks down of power tiller, 57.2% is caused by the old parts of power tiller with the value of 5.18 times break down a year and 34.7% was caused by the poor maintenance and over loading. 2) For the power tiller which was purchased in less than two years, more breaks down were caused by poor maintenance in comparison to the old parts of power tiller. 3) For the both 8-10 HP kerosene and diesel engine power tiller, the aspects of breaks down was almost the same. But for the 5 HP power tiller, more breaks down was caused by over loading in comparison to the old parts of power tiller. 4) For the cylinder system and traction device, most of the breaks down was caused by the old parts and for the fuel and ignition system, breaks down was caused mainly by the poor maintenance. D. Repair Cost 1) For each power tiller, repair cost was 34,509 won a year and it was 97 won for one hoar operation. 2) Repair cost of kerosene engine power tiller was 40,697 won a year, and it use 28,320 won for a diesel engine power tiller. 3) Average repair cost for one hour operation of kerosene engine power tiller was 103 won, and 86 won for a diesel engine power tiller. No differences were found between the horse power of engines. 4) Annual repair cost of cylinder system was 13,036 won which is the highest one compared with the repair cost of any other parts 362 won a year was required to repair the steering device, and it was the least among repair cost of parts. 5) Average cost for repairing the power tiller one time was 3,183 won. It was 10,598 won for a cylinder system and 1,006 won for a steering device of power tiller. E. Time requirement for repairing by owner. 1) Average time requirements for repairing the break down of a power tiller by owner himself was 8.36 hours, power tiller could not be used for operation for 93.58 hours a year due to the break down. 2) 21.3 hours were required for repairing by owner himself the break down of a power tiller which was more than 6 years old. This value is the highest one compared with the repairing time of power tiller which were purchased in different years. Due to the break down of the power tiller, it could not be used for operation annually 127.13 hours. 3) 10.66 hours were required for repairing by the owner himself a break down of a diesel engine power tiller and 6.48 hours for kerosene engine power tiller could not be used annually 99.14 hours for operation due to the break down and it was 88.67 hour for the diesel engine power tiller. 4) For both diesel and kerosene engine power tiller 8 HP power tiller required the least time for repairing by owner himself a break down compared with any other horse power tiller. It was 2.78 hours for kerosene engine power tiller and 8.25 hours fur diesel engine power tiller. 5) For the cylinder system of power tiller 32.02 hours were required for repairing a break down by the owner himself. Power tiller could not be used 39.30 hours a year due to the break down of the cylinder system.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2003.07a
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• pp.140-148
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• 2003

수송 중에 일어나는 과채류의 손실에 대한 주요 자료들을 정리하여 보면 주요 쟁점은 수송 중에 발생된 가속도와 주파수의 크기, 적재방법과 적재 위치, 3차원진동과 수송속도에 따라 농산물이 어떤 손상을 입으며 저장성과 상품성에 어떻게 영향을 미치는가 하는 문제로 요약된다. 그러나 우리나라의 농가에서 운반용으로 주로 사용되고 있는 동력경운기 트레일러는 현가장치와 진동흡수장치가 없는 것으로 농산물의 운송시에 발생되는 충격ㆍ진동 등으로 인해 많은 수송 손실이 예상된다. 결론적으로 트레일러에 전달되는 진동을 줄이기 위해서는 트레일러에 스프링 시스템을 장착하고, 엔진과 연결되는 히치 부분에 진동흡수 시스템을 장착하여 트레일러에 전달되는 진동을 최소화시키는 방법을 강구하여야 한다. (중략)

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1995.06a
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• pp.18-24
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• 1995

본 연구에서는 두가지 엔진에 사용된 엔진오일의 성상변화를 측정하였다. 따라서 금속 마모입자 분석, 동점도 측정과 TAN 및 TBN 분석을 통한 물리적 성상과 화학적 성질 분석 그리고 적외선 분광 분석과 정량 폐로그라피 분석 등을 통하여 Table 1에 나타난 기준에 의해 오일의 수명을 판정하였다. 아울러 RPD를 이용하여 마모입자의 형상 등을 분석하고 엔진에서 발생하는 마모기구를 살펴보았다. 물론 본 연구는 주위 환경이 양호한 실험실에서 엔진 동력계에 의한 실험에 의존하였으므로 실제 주행실험 결과보다는 오일의 수명이 더 길게 나타날 것으로 예측된다. 더욱이 농경지에서 주로 사용되는 경운기의 경우는 오일이 먼지나 모래, 진흙 등에 의해 오손되기 쉬우므로 실제 오일의 수명은 훨씬 더 짧을 것으로 생각되므로 실차 주행실험 결과와의 비료는 앞으로 더 연구할 분야로 생각된다.

• Journal of Biosystems Engineering
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• v.22 no.2
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• pp.189-198
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• 1997

In order to find out the potential of LP gas as a substitute fuel for small fm engine, experiments were carried out with a four-stroke spark-ignition engine which was modified from a kerosene engine mounted on the power tiller. Performance characteristics of kerosene and LP gas engine such as torque, volumetric efficiency fuel consumption rate, brake thermal efficiency, exhaust temperature, and carbon monoxide and hydrocarbon emissions were measured and analyzed under various levels of engine speed and compression ratio. The results were summarized as follows. 1. It showed that forque of LPG engine was 41% lower than that of kerosene engine with the same compression ratio, but LPG engine with compression ratio of 8.5 it was showed similar torque level to kerosene engine with compression ratio of 4.5. 2. Fuel consumption of LPG engine was reduced by about 5.1% and thermal efficiency was improved by about 2% compared with kerosene engine with the same compression ratio. With the incrasing of compression ratio in LPG engine fuel consumption rate decreased and thermal efficiency increased. 3. Exhaust temperature of LPG engine was about 15% lower than that of kerosene engine. Concenrations of emissions from LPG engine was affected insignificantly by compression ratios, and carbon monoxide emissions from the LPG engine was not affected by engine speed so much. The carbon monoxide and hydrocarbon emissions from LPG engine were about 94% and 66% lower than those of kerosene engine, respectively.