• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.4
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• pp.865-870
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• 2008

The effects of exhaust gas recirculation (ECR) on smoke emissions in heavy duty diesel engine are numerically studied by using KIVA-3V CFD code. For the analysis, RNG k-$\varepsilon$ turbulence model was given as a governing equation, and mathematical models of Tab, Wave, Watkins-Park, Nagle-Strikland were applied to describe physical process of droplet breakup, atomization, wall impingement and smoke respectively.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.6
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• pp.59-64
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• 2002

The effects of EGR on emissions were investigated by using a six-cylinder, 8 litre, turbo-charged, heavy-duty diesel engine with a low pressure route EGR system. The experiments were performed at various engine loads while the EGR rates were set from 0% to 30%. Hot and cooled EGR are achieved without cooling and with cooling respectively. To verify the possibility of EGR technology for the applications, test were performed with steady state test cycle. It was found that the exhaust emissions with the EGR system resulted in a very large reduction in oxides of nitrogen at the expense of higher smoke and PM emissions. Increasing the EGR rate leads to deteriorating specific fuel consumption and power at lower speed and higher load. Also, the reduction rates of NOx emissions for hot and cooled EGR are similar.

• Transactions of the Korean hydrogen and new energy society
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• v.22 no.5
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• pp.735-740
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• 2011

본 연구에서는 직접분사식 CNG기관의 희박한계를 보다 확장하여 고효율 및 저배기 공해를 실현시키고자 실린더 내에 고압의 천연가스를 직접분사함과 동시에 흡입과정 중 흡기관 내에 소량의 저압천연가스를 보조분사하는 경우의 희박한계 확장 및 제반특성에 대해 검토하였다. 그 결과, 흡기보조분사가 없을 경우 희박한계가 ${\lambda}$ = 1.4 까지였으나, 흡기보조분사율이 5~15% 정도에서는 희박한계가 ${\lambda}$ = 1.5 까지 확장되었다. 이는 흡기보조분사에 따른 혼합기의 혼합율 향상에 기인한 것으로 해석하였다. 연소기간은 줄어들었지만, 흡기보조분사의 효과는 주연소기간에서 조기연소기간보다 강하게 나타났다.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.3090-3095
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• 2008

In this study, variable compression ratio system(VCRS) was applied on the heavy-duty CNG engine and the characteristics of power and emission was investigated according to the increasing of compression ratio. As compression ratio increasing, the increasing of thermal efficiency in direct injection is three times higher than that in port injection. The emission of HC and CO in direct injection is reduced about 14.2%, 17.7% but NOx is increased because of increasing temperature in cylinder.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.5
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• pp.788-792
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• 2006

The test was conducted on an 8000cc heavy-duty turbo-charged heavy-duty diesel engine on which continuous regeneration DPF was installed in order to investigate regeneration characteristics fur DPF and engine performance under conditions of standard (430ppm) or ultra low sulfur diesel (50ppm) and the results were compared with each other. Exhaust emissions, CO, HC, NOx, PM and soot were investigated carefully and tested under D-13 and D-3 modes.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.6
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• pp.89-95
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• 2000

The engine idle speed mode becomes worse as one drives a vehicle for several years. This is due to ageing of engine and power-train parts. In this case, unstable idle conditions such as engine stall and droop are frequently experienced when the engine gets heavy torque loads due to power steering pump and air conditioning compressor. The objective of this paper is to study on the idle speed control using PID controller under load disturbances. The input of the PID controller is an error of rpm. The output of the PID controller is an ISCV duty cycle. The dSPACE Controller Boards are used to interface with engine. The on-vehicle test is realized using by SIMULINK and BLOCKSETS tools. The real time interface control panel supplied by Control Desk S/W is designed to have good results in engine idle speed control.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2000.11a
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• pp.122-128
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• 2000

• International Journal of Automotive Technology
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• v.6 no.2
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• pp.133-139
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• 2005

In this study, a three-dimensional transient simulation with a knock model was performed to predict knock occurrence and autoignition site in a heavy-duty LPG engine. A FAE (Flame Area Evolutoin) premixed combustion model was applied to simulate flame propagation. The coefficient of the reduced kinetic model was adjusted to LPG fuel and used to simulate autoignition in the unburned gas region. Engine experiments using a single-cylinder research engine were performed to calibrate the reduced kinetic model and to verify the results of the modeling. A pressure transducer and a head-gasket type ion-probe circuit board were installed in order to detect knock occurrences, flame arrival angles, and autoignition sites. Knock occurrence and position were compared for different piston bowl shapes. The simulation concurred with engine experimental data regarding the cylinder pressure, flame arrival angle, knock occurrence, and autoignition site. Furthermore, it provided much information about in-cylinder phenomena and solutions that might help reducing the knocking tendency. The knock simulation model presented in this paper can be used for a development tool of engine design.

• Journal of the Korean Institute of Gas
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• v.20 no.4
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• pp.1-6
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• 2016

A fuel supply system of heavy-duty CNG engine is composed as a module structure which is integrated by about 6 injectors. There are only one input and output passage for gas fuel supply in this injector module. The response performance for transient operation of an CNG engine is very poor because only one output fuel supply line is connected to the intake pipe after a throttle valve. In this study, a new guideline and internal flow design for the CNG injector module is suggested for the improvement of response performance by fluid dynamic simulations. As a result, the response performance of gas fuel supply can be improved by decreasing the total volume of internal flow passages and a same distance design from each injector to the exit of module shows good response performance and acquirement of linearity of fuel supply. But the injection order has little influence to injection performances.

• Journal of Korean Society for Atmospheric Environment
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• v.21 no.6
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• pp.585-592
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• 2005

Nowadays it has been strongly required to control emissions from vehicles specially in diesel engines because of increasing number of vehicle in korea. This research aims to provide with some of deterioration factors on vehicles for emissions characteristics and the test was done on an electronically controlled heavy-duty diesel engine under severe driving conditions such as 1200 driving hours, 220,000 km driving distance and a full load. Under various driving conditions, CO, HC, $NO_{x}$, PM and Soots emissions were estimated under D-13 mode and D-3 mode respectively. CO emission was not changed until 500 running hours, and as engine aging is progressed THC was not changed until 500 running hours but it decreased to about $33\%,\;NO_{x}$ decreased constantly but on the other hand PM increased up to $6.9\%$ during the aging process.