• 동력기계공학회지
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• 제10권2호
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• pp.11-15
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• 2006

The increasing numbers of automobiles keep causing air-pollution problems worse than ever. Nowadays, research on catalyst converter and filter trap as a modern technology is very active because PM is designated as a major cancer material and stringent regulations on this are necessary and required. This research emphasized on the development of Continuously Regenerating DPF technology which was the best particulate matters removing technology of current existing technology because of its superior comparability and high applicability. This experimental study has been conducted with equipped and unequipped a Continuously Regenerating DPF ona displacement 7,000cc diesel engine and compared in terms of engine performance and emission. To measure the emission, D-13 mode is applied and measured quantities of the exhaust gases, particularly in CO, HC, PM, and NOx. Therefore, this research is focused on engine performance and characteristics on exhaust emissions with the application of a Continuously Regenerating DPF in a heavy-duty diesel vehicle.

• 한국자동차공학회논문집
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• 제12권4호
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• pp.1-11
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• 2004

Combustion and fuel distribution characteristics of heavy duty engine with the liquid phase LPG injection(LPLI) were studied in a single cylinder engine, Swirl ratio were varied between 1.2, 2.3, and 3.4 following Ricardo swirl number(Rs) definition, Rs=2.3 showed the best results with lower cycle-by-cycle variation and shorter burning duration in the lean region while strong swirl(Rs=3.4) made these worse for combustion enhancement. Excessive swirl resulted in reverse effects due to high heat transfer and initial flame kernel quenching. Fuel injection timings were categorized with open valve injection(OVI) and closed valve injection(CVI). Open valve injection showed shorter combustion duration and extended lean limit. The formation of rich mixture in the spark plug vicinity was achieved by open valve injection. With higher swirl strength(Rs=3.4) and open valve injection, the cloud of fuel followed the flow direction and the radial air/fuel mixing was limited by strong swirl flow. It was expected that axial stratification was maintained with open-valve injection if the radial component of the swirling motion was stronger than the axial components. The axial fuel stratification and concentration were sensitive to fuel injection timing in case of Rs=3.4 while those were relatively independent of the injection timing in case of Rs=2.3.

• 한국자동차공학회논문집
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• 제14권2호
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• pp.84-91
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• 2006

A heavy duty hydrogen-natural gas fueled engine can obtain stable operation at ultra lean conditions and reduce emissions extremely. Reduction of $CO_2$ in its engine is one of the most benefit. In this study, rate of hydrogen addition($R_{dH2}$) and compression ratio($\varepsilon$) were investigated including performance of this engine. As results, it was found that phenomenon of pressure oscillation when increasing $R_{dH2}$ and $\varepsilon$, it means occurring knock. It consider that pressure oscillation was increased due to fast burning speed of hydrogen. Even if same compression ratio, pressure oscillation was remarkable increased according to increasing $R_{dH2}$. Therefore, limit compression ratio of knock occurring was reduced by increasing $R_{dH2}$.

• 한국자동차공학회논문집
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• 제14권1호
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• pp.68-78
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• 2006

In the past few years, considerable efforts have been directed towards the further development of Urea-SCR(selective catalytic reduction) technique for diesel-driven vehicle. Although urea possesses considerable advantages over Ammonia$(NH_3)$ in terms of toxicity and handling, its necessary decomposition into Ammonia and carbon dioxide complicates the DeNOx process. Moreover, a mobile SCR system has only a short distance between engine exhaust and the catalyst entrance. Hence, this leads to not enough residence times of urea, and therefore evaporation and thermolysis cannot be completed at the catalyst entrance. This may cause high secondary emissions of Ammonia and isocyanic acid from the reducing agent and also leads to the fact that a considerable section of the catalyst may be misused for the purely thermal steps of water evaporation and thermolysis of urea. Hence the key factor to implementation of SCR technology on automobile is fast thermolysis, good mixing of Ammonia and gas, and reducing Ammonia slip. In this context, this study performs three-dimensional numerical simulation of urea injection of heavy-duty diesel engine under various injection pressure, injector locations and number of injector hole. This study employs Eulerian-Lagrangian approach to consider break-up, evaporation and heat and mass-transfer between droplet and exhaust gas with considering thermolysis and the turbulence dispersion effect of droplet. The SCR-monolith brick has been treated as porous medium. The effect of location and number of hole of urea injector on the uniformity of Ammonia concentration distribution and the amount of water at the entrance of SCR-monolith has been examined in detail under various injection pressures. The present results show useful guidelines for the optimum design of urea injector for reducing Ammonia slip and improving DeNOx performance.

• 한국자동차공학회논문집
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• 제22권7호
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• pp.48-56
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• 2014

Engine oil is an oil used for lubrication of various internal combustion engines. The main function is to reduce wear on moving parts; it also cleans, inhibits corrosion, improves sealing, and cools the engine by carrying heat away from moving parts. In engines, there are parts which move against each other. Otherwise, the friction wastes the useful power by converting the kinetic energy to heat. Those parts were worn away, which could lead to lower efficiency and degradation of the engine. It increases fuel consumption, decreases power output, and can induce the engine failure. This study was conducted to evaluate the relation between engine oil property changes and engine performance for the diesel engine. This test was performed by using 12L, 6 cylinder, heavy duty engines. Low SAPS 10W30 engine oil (two type engine oils) was used. Test procedure and method was in accordance with the modified CEC L-57-T97 (OM441LA) method. In this study, TAN, TBN, KV and metal components, engine power, blowby gas, A_F were presented to evaluate the relation with engine oil property changes and engine performance. TAN, TBN, KV and metal We found that the components were generally increased but engine performance did not change. This results mean that property changes did not affect on engine performance because those were not enough to affect engine performance.

• 대한기계학회논문집A
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• 제22권2호
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• pp.437-443
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• 1998

Automobile company tries to reduce the inertia of powertrain to increase the fuel efficiency and increase the engine power every year to make the high speed driving possible at full load condition. These cause the torsional vibration of powertrain. But the demand about ride comfort improvement is increased constantly, so torsional vibration of powertrain become an emergency problem to be cured. This study is a basic research to reduce the torsional vibration of powertrain at driving condition. First, the heavy duty powertrain is characterized as a vibrating system. Its natural frequencies and mode shapes are reviewed. Second, by comparison of simulation results and experiment results, validity of developed model is verified. Finally, the couterplan which can reduce the torsional vibration by mode analysis and parameter modification is suggested.

• 대한기계학회논문집A
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• 제39권2호
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• pp.203-209
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• 2015

건설기계 산업에서 배기 및 연비 규제를 만족하기 위하여 엔진 시스템이 점차 전자제어화 되고 있으며, 이를 제어하기 위한 EMS(Engine Management System)의 복잡도 또한 증가하고 있다. 본 연구에서는 EMS function 개발 시, 비용 및 개발기간의 단축을 위한 HiLS(Hardware in the Loop Simulation) 시스템을 개발하였다. HiLS 에 내장된 엔진 모델은 크게 Air, Fuel, Torque 및 동력계 모델로 구성되어있고 실시간 엔진 모사를 위하여 Mean value modeling 방법을 적용하였다. 이 연구를 통하여 개발한 HiLS 시스템은 EGR(Exhaust Gas Recirculation) 시스템과 Turbocharger 가 장착된 건설기계용 디젤엔진을 이용하여 정확성을 검증하였고, 테스트 결과 실 엔진 대비 90% 이상의 정확도를 얻었다.

• 한국정밀공학회지
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• 제31권7호
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• pp.627-634
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• 2014

Machine tool vibration is well known for reducing machining accuracy. Because vibration response of a linear structure generally depends on its transfer function if the magnitude of excitation were kept constant, this study introduces a RET(Random Excitation Test) based on FRF method to evaluate stiffness of a prototype HDMTL(Heavy-Duty Multi-Tasking Lathe) for large crankshaft of marine engine. Firstly, two force loops of the lathe and corresponding structural loops were identified:1) workpiece - spindle - head stock - main bed, 2) workpiece - tool post - carriage bed. Secondly, compliances of each structural loop were measured respectively using RET with a hydraulic exciter and then converted into stiffness. Finally, the measured stiffness was compared with that obtained previously by FEM analysis. As the result, both measured and computed stiffness were closely in agreement with each other. And the prototype HDMTL has evidently sufficient rigidity above ordinary heavy-duty lathes.

• 한국자동차공학회논문집
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• 제8권3호
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• pp.12-17
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• 2000

In this study a heavy duty diesel engine was modified into a 11-liter 6-cylinder SPI CNG dedicated engine, which was tested to investigate the performance and exhaust emission under the maximum load condition as the engine speed was increased in the range of 1,000∼2,200 rpm. The exhaust emission was also measured at D-13 mode as well as AVL-8 mode.

• 한국자동차공학회논문집
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• 제22권1호
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• pp.165-173
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• 2014

The method of emission inspection for Heavy-duty diesel vehicles has been engine speed type Lug-down 3mode. This method could bring damage to decrepit vehicles under high speed and high load condition and it could not apply the driving pattern on the road. For these reasons, this study has started to create new emission inspection which is appropriate for Korea's road infrastructure. KD 147 would be applied to light-duty diesel vehicles from july 2010 after model operations. Therefore, this study has investigated new emission inspection system for heavy-duty diesel vehicles, except for light-duty diesel vehicles. In consideration of domestic conditions to meet the new load test method in this study, the Lug-down3 mode vehicle speed method was developed for the first time in korea.