냉각팬 전자제어를 통한 시내버스의 연비 개선

김기복(Kibok Kim),박진일(Jinil Park),이종화(Jonghwa Lee),박경석(Kyoungseok Park) 한국자동차공학회 2013 한국 자동차공학회논문집 Vol.21 No.6

가솔린 엔진 장착 차량에서 연속 가변 밸브 리프트 제어가 모드 연비에 미치는 영향

김기복(Kibok Kim),위효성(Hyoseong Wi),박진일(Jinil Park),이종화(Jonghwa Lee) 한국자동차공학회 2009 한국자동차공학회 학술대회 및 전시회 Vol.2009 No.11

CVVL control system is the technology that adjusts engine load by changing valve lift continuously. It satisfies the load that driver demands by changing the amount of opening of the valve, while maintaining the intake pressure after the valve of atmospheric pressure. Because of CVVL control system, we can expect decrease pumping loss and engine mechanical friction, increase volumetric efficiency in all load and good fuel economy. In this study, perform engine test on no load condition and FTP-75 mode test. The specification of test vehicle is 1600cc gasoline engine. check the effect on CVVL which decrease engine mechanical friction and decrease pumping loss. As a result of engine test on no load, engine total friction is decrease 14.7%. portion of engine mechanical friction is 9.2% and pumping loss is 4.5% in engine total friction. As a result of FTP-75 mode test, fuel economy is 6.06% improvement. portion of engine mechanical friction is 2.66% and pumping loss is 1.82% in engine total friction. Also decrease engine mechanical friction and pumping loss in whole section of FTP-75 mode.

미국과 일본의 중대형차 연비 규제안 비교 분석

김기복(Kibok Kim),염시호(Siho Yeom),박진일(Jinil Park),이종화(Jonghwa Lee) 한국자동차공학회 2011 한국자동차공학회 학술대회 및 전시회 Vol.2011 No.11

Around the world consider a reducible method of greenhouse gas because of obligation to reduce greenhouse gas emissions. Regulations are strictly application at normal cars. But heavy duty vehicles regulations confirm only U.S. and Japan. In this paper Compare U.S and Japan`s fuel economy regulations of heavy duty vehicles based on simulation and classified fuel economy. It also classify Heavy duty Vehicles of domestic production depending on USA&Japan regulation

시내버스에서 변속 지시기 적용에 따른 실도로 연비 특성 분석

김기복(Kibok Kim),염시호(Siho Yum),박진일(Jinil Park),이종화(Jonghwa Lee),박경석(Kyoungseok Park),박준홍(Junhong Park) 한국자동차공학회 2011 한국자동차공학회 부문종합 학술대회 Vol.2011 No.5

A shift pattern is a very important factor on a vehicle fuel economy. Especially for manual transmission vehicles, a fuel economy varies according to a driver’s tendency. If an indicator put a driver on notice of gear shift on pertinent point of time, the fuel economy can be improved. This paper focuses on fuel economy improvement through change of gear shifting engine speed and presents a gear shift algorithm considering a traction force, an APS, a vehicle acceleration and a BSFC(Brake Specific Fuel Consumption). Shift Indicate Algorithm considering a measure or calculate of engine speed, vehicle acceleration depend on APS, engine efficiency, traction force after gear shifted. Drivers can shift along embedded computer of applied shift algorithm. From simulation result of simulink and Cruse(AVL), we verify an algorithm. and parameter tuning from field test. The specification of test vehicle is 11000㏄ CNG engine, manual transmission. and the test condition is two cases, regular drive of bus company driver and drive depend on shift indicator. driving route is urban bus line of suwon city. Our team got a result from field test, 18% of vehicle fuel economy improvement can be achieved comparing to regular drive. that is because of higher engine efficiency, lower engine speed and lower acceleration.

머신러닝을 활용한 시내버스 연비 운전 점수화 알고리즘 개발

김기복(Kibok Kim),이종화(Jonghwa Lee),박진일(Jinil Park) 한국자동차공학회 2022 한국자동차공학회 학술대회 및 전시회 Vol.2022 No.11

An eco-drive system was implemented on urban buses in Seoul. The system includes a shift indicator and the calculation of eco-drive score. With the implementation, 3,864 vehicles showed improvement in fuel economy by 12.1% annually. The eco-drive score indicates the degree of fuel economy of driving by monitoring acceleration and deceleration, timing of gear shift, accelerator pedal gradient, and coasting rate. During the annual operation, the eco-drive score showed discrepancy depending on the driving environment. This revealed the need to improve the linearity between fuel economy and the score. The eco-drive score was calculated based on OBD data, and external factors such as traffic environment and road conditions were not considered. In this study, the environmental factors of fuel economy were identified to supplement the eco-drive score. This is achieved by developing a machine learning fuel economy prediction model. The environmental factors are examined by assessing the contribution of each input variable (feature) of the fuel economy prediction model through SHAP-value. The driving start time, driving date, number of gear shifts per unit distance, and brake operation ratio during driving were set as the environmental factors of fuel economy. The measured fuel economy is normalized using the relationship between the average fuel economy and each of the environmental factor of the annual driving data. The eco-drive score is corrected in the range of 0.84-1.05 times based on the normalized fuel economy distribution of the equivalent eco-drive score. A corrected eco-drive score prediction model was developed, and the environmental factor of the fuel economy was used as the prediction model feature of the eco-drive score. The eco-drive score increased with an increase in the normalized fuel economy. The correlation between fuel economy and eco-drive score was 34% improved by considering the environmental factors of fuel economy.

시내버스 변속 패턴에 따른 연비 특성 분석

김기복(Kibok Kim),박진일(Jinil Park),이종화(Jonghwa Lee),박경석(Kyoungseok Park),김우석(Wooseok Kim) 한국자동차공학회 2009 한국자동차공학회 부문종합 학술대회 Vol.2009 No.4

A shift pattern is a very important factor on a vehicle fuel economy. Especially for manual transmission vehicles, a fuel economy varies according to a driver's tendency. If an indicator put a driver on notice of gear shift on pertinent point of time, the fuel economy can be improved. This paper focuses on fuel economy improvement through change of gear shifting engine speed and presents a gear shift algorithm considering a traction force, an APS, a vehicle acceleration and a BSFC(Brake Specific Fuel Consumption). The bigger portion of high gear stage is, the better the engine efficiency and lower total cycle there will be. So the fuel economy of the vehicle becomes better. The specification of test vehicle is 6000㏄ diesel engines and the test condition is two cases, shift on high engine speed and shift on low engine speed. In the case of real experiment on the road, when the shift the gears at the normal condition, it was showed a preponderance of 25% at the shift on low engine speed in the average of twice experiments but the result of only 9% at the shift on high engine speed. That is, the lower engine speed is, the better fuel economy is presented. There are similar result at the simulation. However, if the engine speed is low in a gear shift, the vehicle can not be sufficient traction force. So, vehicle speed will be low or the section that can not follow required vehicle speed is occurred. In order to improve these problems, presented a gear shift algorithms that is considering a traction force. Our team got a shift profile to algorithm and applied it to the simulation. As a result, 13.7% of vehicle fuel economy improvement can be achieved comparing to normal condition.

대기업의 협력회사에 대한 품질지도 활동 효과성 검증 연구

김기복(Kim, Kibok),김재성(Kim, Jaesung),권순동(Kwon, Sundong) 한국산업경영학회 2016 經營硏究 Vol.31 No.3

협력회사의 품질수준 향상은 모기업의 품질수준 향상과 생산성 향상으로 이어지고 결국은 협력 회사의 품질경쟁력이 모기업의 경쟁력에 기여한다는 사실은 많은 연구를 통해 밝혀진 바 있다. 본 연구에서는 대기업의 협력회사에 대한 품질지도 활동에 대해 살펴보고, A 대기업 활동 결과를 바탕으로 활동 효과에 대해 통계적으로 분석을 실시했으며, 연구결과는 다음과 같다. 첫째, 대기업의 품질지도 활동은 협력회사의 품질성과에 긍정적인 영향을 미치는 것으로 확인되었다. 따라서 대기업이 중심이 되어 협력회사에 대한 품질지도 활동을 더욱 확대할 필요가 있다. 둘째, 대기업의 품질지도 활동은 협력회사의 모기업 의존도가 높을수록 품질성과 변화가 크게 나타나며, 품질성과 변화는 즉시 나타나는 것으로 확인 되었다. 따라서 품질지도 활동 대상 협력회사 선정 시, 모기업 의존도를 고려할 필요가 있고, 특히, 라이프사이클이 짧은 제품을 생산하는 기업에서는 반드시 고려해야 할 것이다. 셋째, 대기업의 품질지도 활동은 협력회사에 품질관리 전담자가 있는 경우, 품질성과 변화가 크며, 품질성과 변화가 빠르게 나타나는 것으로 확인 되었다. 협력회사는 품질관리 전담자를 우선 확보하여 품질관리 기능을 합리적으로 수행할 수 있도록 해야 하며, 나아가 타 부서의 영향을 받지 않도록 독립된 품질 전담 조직 구성을 검토해야 할 것이다. 본 연구결과는 대기업의 협력회사에 대한 품질지도 활동 시, 시행착오를 줄이고 선택과 집중을 통해 활동 효과를 극대화 하는데 기여할 것이다. A lot of research showed that improving the quality level of supplier affects to the corporation’s productivity and even to the competitiveness. This study dealt with the effect of corporation’s quality instruction and showed the result of statistical analysis conducted by the instruction. Firstly, it was founded that large corporations’ quality instruction can help their suppliers achieve the goal for quality performance. Thus, the more instructions should be conducted by the corporations which have a lot more resources than their suppliers. Secondly, a high level of dependency on buyer leads to more considerable and rapid quality improvement and the change appears immediately. Therefore, the dependence on buyer should be a key factor when choosing the supplier for the quality instruction. This study also shows that suppliers breeding up their own quality experts create more results in less time. It’s verified that suppliers should set up the exclusive organization of quality management and train the experts for their better performance. Based on this study, we expect to prevent trial and error in quality instruction for suppliers and maximize the effectiveness with more focused strategy.

교류발전기의 효율이 모드연비에 미치는 영향

강혜현(Hyehyun Kang),김기복(Kibok Kim),박진일(Jinil Park),이종화(Jonghwa Lee) 한국자동차공학회 2009 한국자동차공학회 학술대회 및 전시회 Vol.2009 No.11

An alternator is a device that converts mechanical energy produced from the engine to electrical energy necessary to car. Then, the converting electrical power does not equal the converted mechanical power because of the efficiency of the alternator. The difference between converting power and converted power is the power loss and the magnitude of which is decided by the alternator efficiency. In this study, to figure out the effect of alternator efficiency on fuel economy, simulate model of car on the FTP-75 mode by using data of alternator efficiency obtained from experiments. Fuel economy of FTP-75 is positive affected by higher efficiency alternator and influence of alternator efficiency on fuel economy varies according to the cars.

시내버스 변속 시점에 따른 연비 개선 효과 분석

허미미(Mimi Heo),김기복(Kibok Kim),박진일(Jinil Park),이종화(Jonghwa Lee),박경석(Kyoungseok Park) 한국자동차공학회 2010 한국자동차공학회 학술대회 및 전시회 Vol.2010 No.11

Gear shift timing is a important factor of fuel economy improvement in the vehicle. Drivers do to shift gears from their experience, Because they don’t know objectively when is the best timing to shift gears from fuel economy point of view. Commercial vehicles such as bus and truck are usually used the manual transmission. In this case, CO2 emission and fuel economy are difference in maximum 30% according to driver’s gear shift pattern. The bigger portion of high gear stage is, the better the engine efficiency and lower total cycle there will be. So the fuel economy of the vehicle becomes better. However, if the engine speed is low in a gear shift, the vehicle can not be sufficient tractive force. So, vehicle speed will be low or the section that can not follow required vehicle speed is occurred. In order to improve these problems, the earlier studies made an algorithm to find the best timing for gear shift using the engine speed, tractive force and BSFC. But tractive force is difficult to predict on the vehicles. In this study, when drivers shift gears by overall consideration about engine speed, load and vehicle acceleration instead of tractive force, the effect of fuel economy improvement was analysis.

초음파 시뮬레이션을 이용한 거친면의 파동 산란에 대한 통계적 연구

최원재(Wonjae Choi),김기복(Kibok Kim),권세곤(Segon Kwon) 한국비파괴검사학회 2018 한국비파괴검사학회지 Vol.38 No.3

초음파 검사는 주요 비파괴 평가방법 중 하나로서, 깊은 투과율 및 안전성 등의 장점으로, 다양한 분야에 널리 사용되고 있는 방법이다. 검사 대상체내의 결함검사에서, 결함에 대한 초음파의 반사파를 이용하여 결함의 유무 혹은 크기 등을 추정한다. 인공결함이 아닌, 자연발생된 결함은 거친표면을 갖게 되는데, 반사파의 특성은 필연적으로 결함 자체의 거칠기와 밀접한 관계가 있다. 거칠기가 높으면 초음파 산란이 일어나 응답진폭이 낮아지게 되고, 거칠기가 낮으면 높은 응답신호를 얻을 수 있다. 초음파 산란은 거칠기의 절대값 보다 입력 주파수 파장대비 거칠기에 대한 정보가 중요하며, 이에 대한 산란예측이 가능하다면, 산란정보에 근거한 검사방법을 개발하여 결함발견률을 높이기 위한 유용한 기반이 될 수 있다. 표면의 거칠기는 일반적으로 통계적인 방법으로 표현되고, 따라서 거친표면에서의 반사 또한 통계적인 방법으로 기술될 수 있다. 통계적으로 유의미한 결과를 얻기 위해서는 많은 수의 샘플이 필요하지만, 실험적인 결과를 얻는데는 한계가 있기 때문에, 가상실험을 기반으로 통계적인 결과를 도출해 내는 경우가 많다. 본 논문에서는 거친표면산란의 가상실험을 위하여, 거친표면에 대한 초음파 산란의 통계적 해석 방법을 소개하고, 평면파의 수직입사/수직반사에 대하여 Kirchhoff approximation과 유한요소 해석에 기반한 결과를 비교 평가한다. Ultrasonic inspection is a non-destructive evaluation method widely used in various industrial fields for its advantages including deep penetration and safety. The existence or size of a defect is estimated by using the ultrasonic waves reflected from the object to be inspected; defects initiated from natural failure have rougher surfaces. The characteristics of the reflected waves are related to the roughness of the defects. If the surface is significantly rough, ultrasonic scattering occurs and the reflected signal has a low amplitude, but when the surface is less rough, a high response signal can be obtained. In ultrasonic scattering, roughness relative to the input wavelength is more important than its absolute value. Predicting the scattering behavior can be a useful basis for improving the defect detection rate by developing an inspection method based on the scattering information. The roughness of the surface is generally expressed in a statistical manner so that reflections on rough surfaces can be described the same way. A large number of samples are required to obtain statistically meaningful results, but because there are limitations in obtaining such a number of experimental results, it is often the case that statistical results are derived based on virtual experiments. In this paper, we introduce a statistical analysis method of ultrasonic scattering on a rough surface for a virtual experiment of rough surface scattering, and compare the results based on the Kirchhoff Approximation and finite element analysis for normal incidence with vertical reflection of the plane wave.