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Recent research has focused on engine combustion technology as well as application of after-treatment in order to comply with emission regulation. However, it is much more efficient way to control emissions from engine itself and furthermore research on engine control will provide the direction of after-treatment technology in future. Furthermore, emission standard regulation for passenger diesel vehicles has been stringent compared to others and nano-particles will be included in EURO6 regulation in Europe and similar emission standard will be introduced in Korea. A 3.0-liter high-speed diesel engine equipped with by CRDI system of 160 MPa injection pressure, and an intake/exhaust system of V type 6-cylinder turbo-intercooler was applied. The conditions of fuel spray and combustion were investigated by setting up an ETAS system which is a similar condition to the engine dynamometer test.

This research aims to obtain fundamentals regarding overall combustion characteristics of pre-mixed and direct injected type CNG fuel inside a constant volume chamber. A visualization technique was introduced to a constant volume chamber in order to investigate combustion and emission characteristics of premixed and direct injected type CNG fuel inside a constant volume chamber. The experiment on a premixed combustion was conducted by measuring constant pressure and emission and controlling speeds of a swirling motor and equivalence ratios in order to investigate swirling effects on flame propagation. Faster combustion speed and higher combustion pressure were occurred in a direct injected type combustion even under the lean condition of the equivalence ratio 0.6 compared to premixed combustion.

The selective catalytic reduction system has been known well so far in the reduction of NOx emission in diesel vehicles. On the other hand ammonia slip from SCR reactors must be avoided in the process of catalytic conversion. This research focused to investigate optimal urea injection conditions for urea-SCR system using visualization techniques and evaluate the performance of urea-SCR system in a heavy-duty diesel engine. The parametric study was made on gas temperatures, SVs (space velocity) and ARs (aspect ratio). The urea injector was located at the opposite direction of exhaust gases emitted to an exhaust duct. An optimal quantity of urea and conversion efficient at each mode of ND-13 mode was estimated. Furthermore, NOx emission and applied amounts of urea was investigated with respect to driving modes under the condition of with/without SCR, This research may provide fundamentals for the practical use of urea-SCR in future.

The selective catalytic reduction system has been known well so far in the reduction of NOx emission in diesel vehicles. This research focused to evaluate the performance of urea-SCR system in a heavy-duty diesel engine and was proceed in four steps. First, optimal urea injection conditions for system were developed. Second, optimal geometric conditions for a urea injection system were investigated by a numerical simulation technique. The simulation results contribute to determine the layout of engine test. Before performing engine test, SCR reactor was used to observe basic performance on SCR. This observation was made on effective NOx reduction according to gas temperatures, SVs (space velocity) and ARs (aspect ratio). Finally, the engine test is carried out based on results of above experiments.

This research focused on principles and developments of continuous regeneration DPF technology, which is an after-treatment technology for the reduction of particulate matters because of its superior comparability and possible applicability. There were some discussions about engine parameters such as engine driving conditions as well as sulfur contents prerequisite to prevent poisoning effect on oxidation catalysts. Besides, this research discussed mainly about some design points of view based on experimental data, and commercial CFD codes such as CFD-ACE and KIVA-3V were used partially to investigate the affect of back-pressure occurred by CRDPF. The test was done on an 8000cc heavy-duty turbo diesel engine on which continuous regeneration DPF was installed in order to investigate regeneration characteristics of DPF and engine performance under several conditions of standard diesel or 50ppm ultra low sulfur diesel.

EGR, usually, is known as a technique that dramatically reduces NOx emission from diesel engine. Application of this technique, however, is difficult because it is likely to cause the deterioration in fuel consumption and the increase in PM emission. For the heavy-duty diesel engines, especially, trade-off between the PM and NOx formation becomes more severe, as well as may raise the problem in lubricant and durability. [1] Numerous researches, therefore, have been conducted to optimize EGR rate which minimizes emission level of NOx without increasing in PM and reduction of engine power. In this paper, as the research for the 11,000cc turbocharged diesel engine equipped with an EGR valve, one predicted the combustion and reduction characteristics of NO, O2, and CO2. Also, One tried to make a selection of optimized EGR rates based on this results. The emission levels of CO2 were substantially increased according to the increase in EGR rate.