• 한국자동차공학회논문집
• /
• 제8권1호
• /
• pp.148-156
• /
• 2000

For the in-line three cylinder engine whose crankshaft has a phase of 120 degrees, the total sum of unbalanced inertia forces occurring in each cylinder will be counterbalanced among three cylinders. However, parts of inertia forces generated at the No.1 and No.3 cylinders will cause a primary moment about the No.2 cylinder. In order to eliminate this out-of-balance moment, a single balance shaft has been attached to the cylinder block so that the engine durability and riding comfort may be further improved. Accordingly, the forced vibration analysis of the in-line three cylinder engine must be implemented to meet the required targets at an early design stage. In this paper, a method to reduce noise and vibration in the 800cc, in-line three cylinder LPG engine is suggested using the multibody dynamic simulation. The static and dynamic balances of the in-line three cylinder engine are investigated analytically. The multibody dynamic model of the in-line three cylinder engine is developed where the inertia properties of connecting rod, crankshaft, and balance shaft are extracted from their FE-models. The combustion pressure within the No.1 cylinder in three significant operating conditions(1500rpm-full load, 4000rpm-full load and 7000rpm-no load)is measured from the actual tests to excite the engine. The vibration velocities at three engine mounts with and without balance shaft are evaluated through the forced vibration analysis. Obviously, it is shown that the vibration of the in-line three cylinder engine with balance shaft is reduced to the acceptable level .

• 한국산업융합학회 논문집
• /
• 제17권4호
• /
• pp.234-244
• /
• 2014

Recently it has been focused that the automobile engine has developed in a strong upward tendency for the use of the high viscosity and poorer quality fuels in achieving the high performance, fuel economy, and emission reduction. Therefore it is not easy to solve the problems between low specific fuel consumption and exhaust emission control at motor cars. In this study, it is designed and used the engine test bed which is installed with turbocharger and intercooler. In addition to equipped using CRDI by controlling injection timing with mapping modulator, it has been tested and analyzed the engine performance, combustion characteristics, and exhaust emission as operating parameters, and they were engine speeds(rpm), injection timing(bTDC), and engine load(%). From the result of an experimental analysis, peak cylinder pressure and the rate of pressure rise were increased, and the location of it was closer toward top dead center according to the increasing of engine speed and load, and with advancing injection timing. The combustion characteristics are effected by fuel injection timing due to be enhanced the mass burned fraction. Using the engine dynamometer for analyzing the engine performance, the engine torque and power have been enhanced according to advancing the fuel injection timing. In analyzing of exhaust emission, there has been a trade-off between PM and NOx with increasing of engine speed and load, and with advanced injection timing. The experimental data are shown that the formation of NOx has increased and PM, vice versa.

• 한국자동차공학회논문집
• /
• 제10권1호
• /
• pp.1-8
• /
• 2002

Metal surface temperatures around the combustion chamber in a gasoline engine directly affect thermal durability and performance of the engine. Metal surface temperatures are influenced by many cooling factors such as drilled water passage, deflector, combustion chamber wall thickness, pillar, and coolant flow pattern. The object of this study is to learn how the coolant passages and coolant flow pattern in an engine influence to the engine metal surface temperature at engine full load and speed. From the test result, it is suggested a plan to reinforce the engine stiffness and to reduce the thermal stress simultaneously. Also, approaches are introduced to reduce the thermal load on the engine by adjusting the discharging direction from the water pump and by optimizing the water transfer holes in the cylinder head gasket. These methods and the optimized engine cooling system, which were suggested in this paper, were adapted for an engine in progress to eliminate the exhaust valve seat wear.

• 한국자동차공학회논문집
• /
• 제12권2호
• /
• pp.9-16
• /
• 2004

Close-coupled catalyst (CCC) can reduce the engine cold-start emissions by utilizing the energy in the exhaust gas. However, in case the engine is operated at high engine speed and load condition, the catalytic converter may be damaged and eventually deactivated by thermal aging. Excess fuel is sometimes supplied intentionally to lower the exhaust gas temperature avoiding the thermal aging. This sacrifices the fuel economy and exhaust emissions. This paper describes the results of an exhaust heat exchanger to lower the exhaust gas temperature mainly under high load conditions. The heat exchanger was installed between the exhaust manifold and the inlet of close-coupled catalytic converter. The exhaust heat exchanger successfully decreased the exhaust gas temperature, which eliminated the requirement of fuel enrichment under high load conditions. However, the cooling of the exhaust gas through the heat exchanger may cause the deterioration of exhaust emissions at cold start due to the increment of catalyst light-off time.

• Composites Research
• /
• 제20권3호
• /
• pp.63-66
• /
• 2007

Structural analysis of automotive engine cover under vibration excitation is performed by finite element analysis (FEA) in order to identify the critical area of the structure. Assembly load due to the tightening of the bolts as well as the vibration excitation were considered to describe the actual loading condition. Natural frequencies of the system were extracted considering the damping effect of the structure. Dynamic analysis was performed based on the extracted natural frequency of the system. Experimental modal analysis (EMA) and measurement of strains were performed to verify the results of the analysis. Analysis results correlated closely with the experimental results. Analysis and experiments showed that contribution of the assembly load should not be ignored to predict the structural failure of the engine cover.

• Journal of Biosystems Engineering
• /
• 제43권2호
• /
• pp.83-93
• /
• 2018

Purpose: This study derived the consumed power and load characteristics of a tillage operation performed in an upland field located in Seomyeon, Chuncheon, Rep. Korea, where potatoes and cabbages were cultivated in two crops. Methods: A plow and rotavator were mounted on a tractor with 23.7 kW of rated power to perform the tillage operation. The work conditions were determined, considering the actual working speed of the tillage operation performed by the local farmers. The power consumption of the rear axle, engine, and power take-off (PTO), PTO torque, and tractive force were measured under each work condition. The consumed power and load characteristics were analyzed using their average values. Results: The rotary-tillage operation consumed more engine power than the plow operation for the same tractor-transmission gear condition. The PTO in the rotary-tillage operation and the rear axle in the plow operation consumed the most power. The power consumption of the engine and the PTO for the rotary-tillage operation tended to increase as the transmission gears of the tractor and the PTO became higher. In contrast, the rear-axle power consumption was insignificant. In addition, the PTO torque tended to rise as the tilling pitch increased. For the plow operation, the drawbar power and the rear axle power accounted for 68-90% of the engine power. The engine and rear axle power, drawbar power, and tractive force tended to rise as the working speed increased. Conclusions: The power consumption and load characteristics differed for the plow and rotary-tillage operations. They may also differ depending on the soil conditions. Therefore, the power consumption and load characteristics in various work environments and regions should be analyzed, and reflected in the design of tractors and working implements. The results derived from this study can be used as a reference for such designs.

• 한국항행학회논문지
• /
• 제14권1호
• /
• pp.93-101
• /
• 2010

본 논문에서는 터보차저 엔진에서 중요한 문제로 대두되는 응답 특성을 규명하고, 전 부하뿐만 아니라 빈번하게 운행되는 부분 부하 조건 하에서의 엔진 성능을 분석하고자 한다. 시험 결과 컴프레서의 압축비는 1260 rpm 까지는 직선 형태로 급격히 증가하고 이후에는 약 2.5 정도로 완만하게 증가하는 것으로 나타났다. 이때 제동 평균 유효 압력도 압축비에 따라 1260 rpm 까지는 직선적으로 급격하게 증가하다가 1600 rpm 이후부터는 급격히 감소하였다. 과급압이 증가될수록 연비, 공기 과잉률, 제동 평균 유효 압력이 향상되나 중저속 영역보다는 정격 회전수로 갈수록 높아지는 경향이 크게 나타나고 있다. 터보차저는 약 1260 rpm 에서부터 안정적으로 작동되는 것으로 나타났으며 저속 영역에서는 과급기의 특성상 효율이 낮게 나타났다. 이 연구의 결과는 터보차저 엔진의 안정적 부하와 속도 제어 방법에 응용할 수 있다.

• Journal of Advanced Marine Engineering and Technology
• /
• 제28권7호
• /
• pp.1138-1144
• /
• 2004

In order to improve engine performance while overcoming the weak points of Pulse and MPC(Modular Pulse Converter) turbocharging system, a new turbocharging system. "Hi-Pulse system", has been introduced and developed for medium speed diesel engine. HYUNDAI HiMSEN engines. Hi-Pulse system is to utilize not only the benefits of MPC system at higher load but also the ones of Pulse system at lower load. As for the results. the specific fuel oil consumption and NOx emission were lowered compared with the Pulse and MPC system. Performance simulation were carried out to optimize intake and exhaust timing and exhaust duct arrangement and to improve the performance of Hi-Pulse system engine.em engine.

• 한국공작기계학회논문집
• /
• 제12권6호
• /
• pp.104-111
• /
• 2003

In order to collect the engine performance data and determine optimum engine conditions, engine performance test based on interface unit were tested This paper was carried out that engine' performance was developed using interface unit between personal computer and diesel engine. The results of the study are summarized as follows: Interface unit was developed. By using PAL, simulation was carried in order to logic's inspection. From this tea NO$_{x}$ were decreased, otherwise PM were increased. By using EGR system PM were increased by twice in the high load ranges, it was not seen to come into effect in the low load ranges. This system was tested D-l3 mode, the results were decreased more than 50% in the NO$_{x}$ emission.

• 한국자동차공학회논문집
• /
• 제13권5호
• /
• pp.57-63
• /
• 2005

The effects of an urea injection at the exhaust pipe for a 4-cylinder DI(Direct Injection) diesel engine were investigated with the parameters such as urea-SCR(Selective Catalytic Reduction) and EGR system. The urea quantity was controlled by NOx quantity and MAF(Manifold Air Flow). The urea injection quantity can be controlled with the urea syringe pump, precisely. The effects of NOx reduction for the urea-SCR system were investigated with and without ECR engine, respectively. It was concluded that the SUF(Stoichiometric Urea Flow) is calculated and the NOx results are visualized with engine speed and load. Furthermore, the NOx map is made from this experimental results. It was suggested, therefore, that NOx reduction effects of the urea-SCR system without the EGR engine were better than that with the EGR engine except of low load and low speed.