• Journal of the Korean Institute of Gas
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• v.23 no.2
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• pp.68-73
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• 2019

We proposed a method to convert the CO2 emission data of vehicles collected from the chassis dynamometer test from distance unit to energy unit which generally measured from the engine dynamometer tests. In the future, if engine dynamometer tests are limited, it is expected to be applied as an alternative method to calculate CO2 emission based on energy unit through the chassis dynamometer test. At this moment, engine efficiency is required and the test mode average efficiency should be used to improve the accuracy, not the result derived from specific speed and load conditions. Also, this method was applied to foreign data and the results were within 0.2%. However, CO, NOx and THC which have very low emission characteristics except CO2, are limited by the method proposed in this study and need to be considered separatively.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1994.04a
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• pp.76-81
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• 1994

승용차에 있어 엔진의 공회전시나 주행중에 발생하는 여러 형태의 진동 및 소음의 저감은 승차감 및 차량의 안정성에 있어 중요한 과제가 되고 있다. 이러한 소음, 진동은 주로 엔진에서 발생하는 토크의 비주기적인 변동성분이 클러치(clutch), 변속기(transmission), 구동축을 거쳐 바퀴로 전달되는 과정에서 발생한다. 셔플(shuffle)은 주행중 가속페달(accelerator)을 급조작(tip-in, tip-out)하였을 때 차량이 전후로 과도적으로 울렁거리는 종진동 현상을 말하며, 이것은 가속페달의 급조작으로 인해 엔진토크가 큰 변동을 일으키고, 동력전달계를 통해 타이어에 전달된 이 토오크는 타이어축에서 구동측으로 역토오크를 발생시키기 때문에 발생한다. 여기서 팁-인(tip-in)이란 승용차를 저속으로 운전하다가 갑자기 가속페달을 밟는 경우를 말하며, 팁-아웃(tip-out)은 반대로 고속상태에서 갑자기 가속페달을 떼는 경우를 말한다. 실험과 시뮬레이션을 사용한 자동차 동력전달계의 비틀림 진동에 대한 연구는 이미 여러 연구자들에 의해 보고되었다. H.Arai은 2자유도 비선형 모델을 사용하여 클러치 접속시 발생하는 외란과 계의 안정성을 고려하여 시뮬레이션을 수행하였고, M.Kataoka는 기어의 공차(clearance)를 고려한 변속기의 강제 비틀림 진동을 실험과 시뮬레이션을 통하여 해석하였다. 그리고, Wu Hui-Le는 자동차 동력전달계의 비틀림 진동 현상을 실험과 이론적인 계산을 통해 연구하였고, R.J.Comparin는 치타음의 발생구조와 특성을 고찰하고 비서형 비틀림 공진 저감에 의한 치타음 저감 기법에 대하여 연구하였다. 또한 G.J.Fudala는 다자유도 모델을 이용하여 클러치의 비틀림 특서엥 따라 주파수분석을 수행하여 치타음 저감 방법을 연구하였고, T.Sakai는 5자유도 모델을 이용하여 엔진 공회전시 발생하는 치타음에 대해 이론과 실험을 통해 해석하고, 엔진 회전수 변동, 클러치 특성, 변속기의 드래그(drag) 토크의 영향과 치타음 저감을 위한 개선된 클러치 특성을 제시하였다. 이 외에도 Thomas C.T.와 E.P.Petkus는 특정 차량에 대한 동력전달계의 비틀림 진동 현상에 대해 연구하였다. 이러한 연구들로 볼 때, 자동차 동력전달계에서 발생하는 진동은 이론과 실험을 통해 그 해석이 가능하며 설계에 매우 유용하게 이용되고 있음을 알 수 있다. 따라서, 본 연구는 4 실린더 4 싸이클 1.5 L 엔진을 장착한 경승용차의 실차 주행실험을 통해 가속 페달의 급조작에 따른 차체의 종진동 현상을 측정하고, 엔진-변속기-타이어-차체의 반환정계 4자유도 진동모델로 시뮬레이션을 수행하여 실차 주행실험의 결과치와 비교, 분석한 후 클러치 비틀림 특성을 비롯한 자동차 동력전달계의 각 설계인자들이 차체의 종진동에 어떠한 영향을 미치는가를 해석하고자 한다.

• Journal of Power System Engineering
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• v.13 no.4
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• pp.18-23
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• 2009

구면무단변속기(SS-CVT)는 구조가 간단하여 변속기구의 부피와 무게를 기존의 변속기구에 비하여 줄일 수 있으며, 별도의 클러치 없이 출력축의 정회전, 역회전 그리고 중립상태 등을 구현할 수 있다. 본 연구에서는 이러한 구면무단변속기의 기구적 특징과 변속메카니즘을 이용하여 직류모터와 가솔린엔진을 장착한 병렬형 하이브리드차량의 동력전달계를 제안하고자 한다. 이를 위하여 먼저 구면무단변속기의 작동원리에 대해 설명하고 전용 실험장치를 제작하여 무단변속성능을 검증하였다. 또한 직류모터를 보조 동력원으로 사용하는 병렬형 하이브리드차량 동력전달계의 설계를 위해 연결기어비와 구면무단변속기의 변속비를 차량주행성능에 맞추어 설정하였으며, 이를 차량가속성능의 수치 시뮬레이션을 통하여 분석하였다. 시뮬레이션 결과를 바탕으로 구면무단변속기의 하이브리드차량 동력전달계의 적용가능성을 검증하였으며, 연구결과로 선정된 구성요소의 설계파라미터를 이용하여 시작차량을 제작하였다.

• 한국기계연구소 소보
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• s.12
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• pp.37-47
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• 1984

• Aerospace Engineering and Technology
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• v.2 no.2
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• pp.186-198
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• 2003

Small sized engine test stand has been built up and modified to measure the engine performance for 15g class small UAV propulsion systems. An engine performance standard test stand was developed in order to validate the prediction performance and to shoot trobles. The performance data were measured and analyzed for the newly developed gasoline engine.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.8
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• pp.911-917
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• 2013

This is a thesis about the experiment of comparison characteristic of power and exhaust gas in the same condition between diesel engine that is equipped response power 220HP turbocharger to increase effectiveness of the engine which is recently used in a lot of industry which requires high power. Resulting of the experiment with natural aspiration diesel engine and turbocharger diesel engine, difference in low speed is not significant, but in high speed, effectiveness of turbocharger diesel engine is much higher than the other one. In other hand, in exhaust gas experiment, turbocharger model exhausts more $NO_X$ and $O_2$, but it doesn't significantly affect the result when it comes with decreasing of $CO_2$ and effectiveness of increased power characteristic. As a result, the turbocharger diesel engine is economically effective comparing with the natural aspiration diesel engine.

• Journal of the Korean Institute of Gas
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• v.24 no.6
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• pp.28-33
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• 2020

In this study the possibility of hydrogen as a fuel in a small-sized two-stroke SI (Spark ignition) engine was investigated. For this purpose, experimental setup including an engine, a dynamometer, equipments for hydrogen and lubricant oil supply was prepared. And then preliminary experiments for the hydrogen-fueled engine combustion were conducted. In the case of hydrogen-fueled engines comparing to gasoline backfire occurs when the excess air ratio is lower than a specific value. This can cause engine power reduction and damage to the engine parts. The engine was controlled to operate at lean conditions to prevent backfire. Through the control of excess air ratio, the maximum engine brake power output of 3 kW was achieved in a 210 cc engine, while it was 6 kW in case of gasoline fuel.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.1
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• pp.23-30
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• 2014

To improve efficiency of diesel engine which requests high output recently and is used all kinds of industrial areas, this thesis experimented dynamic characteristics and exhaust gas characteristics of diesel engine installed by supercharger of correspondent output 200HP and natural inhalation diesel engine through the dynamometer and exhaust gas analyzer in same condition. As the result of experiment with natural inhalation diesel engine and diesel engine installed by supercharger, there were a few differences of output, but dynamic characteristics at high speed showed increased output and efficiency of the engine installed by supercharger. On the contrary, in exhaust gas characteristics, the model installed by supercharger showed increased exhaust gas such as $NO_X$, $O_2$, etc, but added value of exhaust gas is low if considering $CO_2$ reduction and efficiency of dynamic characteristic's increase. Based on the results, diesel engine installed by supercharger is expected to show higher economic feasibility than natural inhalation diesel than natural inhalation engine from an angle of efficiency. Keywords: 200hp class Turbocharger, Exhaust Gas, Engine Performance, Marine Diesel Engine.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.6
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• pp.1021-1027
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• 2006

Torque fluctuation of an engine and angular velocity variation of a propeller shaft are the main excitation sources in the vehicle driveline. This paper presents brief mechanism of these excitation sources. Equivalent models of these systems are construced to simulate the excitation source. The computer simulation was carried out by ARLA Simul v 6.7 and ARLA-Simstat v 2.3. Results of the simulations show the characteristics of torsional excitation source of the driveline. Experimental setups for engine system and propeller shaft system are constructed with component of the vehicle. Torque fluctuation of the flywheel and angular velocity of the propeller shaft were measured from this experimental setups. Experimental results are compared with simulation results. The results from experimental analysis agree with those from theoretical results.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.1
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• pp.112-121
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• 2001

In this paper, an engine-CVT integrated control algorithm is suggested by considering the powertrain loss, inertia torque and the CVT ratio response lag. The integrated control algorithm consists of (1) the optimal engine power calculation and (2) determining of the optimal throttle valve opening and the optimal CVT ratio. The optimal engine power is obtained by compensating the inertia torque due to the CVT ratio change and the powertrain loss that is calculated iteration procedure. In addition, an algorithm to compensate the effect of the CVT ratio response lag on the drive torque is suggested by the engine speed compensation causing the increased optimal CVT ratio. Simulation results show that the engine-CVT integrated control algorithm developed in this study makes it possible to obtain better engine operation on the optimal operating line, which results in the improved fuel economy while satisfying the driver's demand.