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A 2-LEG NOx Storage-Reduction (NSR) catalyst system is one of potential after-treatment technology to meet stringent NOx and PM emissions standards as Post New Long Term (Japanese 2009 regulation) and US'10. Concerning NOx reduction using NSR catalyst, a secondary fuel injection is necessary to make fuel-rich exhaust condition during the NOx reduction, and causes its fuel penalty. Since fuel injected in the high-temperature (∼250 degrees Celsius) exhaust instantly reacts with oxygen in common diesel exhaust, the proportion of fuel consumption to reduce the NOx stored on NSR catalyst is relatively small. A 2-LEG NSR catalyst system has the decreasing exhaust flow mechanism during NOx reduction, and the potential to improve the NOx reduction and fuel penalty. Therefore, this paper studies the 2-LEG NSR catalyst system. The after-treatment system consists of NSR catalysts, a secondary fuel injection system, flow controlled valves and a Catalyzed Diesel Particulate Filter (CDPF).

The design of intake and exhaust port is a time consuming process in the engine development. It is important to reduce the time of this process in the DI diesel engine developmets. Basically, there are three time consuming parts in this process, which are the port geometry creation, CFD model creation, and making the experimental parts. Port development process is improved using automating technique for the geometry creation and mesh generation of CFD. The geometry creation is performed using CAD system IDEAS. The automatic geometry creation for the typical intake port shape as the directional and helical type are developed using the programming function of CAD system. The CFD code in which the automatic mesh generator is installed is used to predict the port performance from the CAD data. The port box for the experimental measurement is made using Rapid Prototyping. This system is applied to the typical conventional intake port to change the swirl ratio.

The differences between spray models are investigated by comparing calculation results with experimental data. The calculations are performed using the KIVA-II code. The spray models TAB, which is the original model of KIVA-II, and the model developed by Reitz are calculated and compared. A semi-empirical spray model based on the TAB model is also formulated and compared with the other models. The penetration and droplet size distribution are compared with data from constant pressure bomb tests. The calculated ignition delay is compared with actual engine operating data- Each spray model has different characteristics influencing the atomization process. These differences result in discrepancies during the penetration, evaporation, and ignition.

The spray formation for a heavy duty diesel engine is calculated and compared with the direct and Schlieren photography. The calculation is performed by three dimensional numerical analysis based on KIVA computer program. The discrete particle technique is used for the spray modeling. The drag force of the spray droplet in the calculation is adjusted to have a same penetration with the experiment. The calculations are performed to investigate the influence of the evaporation, combustion, and coalesence for the development of the spray. The results of the calculation are visualized using three dimensional iso-surface to compare with the photograph. The comparison shows that the calculated reaults gives the similar feature on the distribution of each property with the experiment.

Recently the analysis of air-fuel mixing and combustion has become important under the stringent emissions regulations of diesel engines. In the case of gasoline engines, the KIVA computer program has been developed and used for the analysis of combustion. In this paper, the calculations of combustion phenomena in DI diesel engines are performed by modifying the KIVA program so as to be applicable to multi-hole nozzles and arbitrary patterns of injection rate. The thermophysical and ther-mochemical properties of gasoline are altered to those diesel fuel. In order to investigate the ability of this modified program, the calculations are compared with the experiments on single cylinder engines concerning the pressure, flame temperature and mass change of chemical species in cylinders. Furthermore, the calculation for the heavy duty DI diesel engine is performed with this diesel combustion program.

In this paper, the flow patterns and velocity distributions of coolant flow around cylinder liners of diesel engine are studied by numerical calculation and experimental observation. The experiment is carried out by oil film method and direct observation with a transparent acrylic cylinder liner. The calculation is performed with the 3-dimensional model by FEM for fluid flow. The motion of coolant flow by calculation corresponds with the result by oil film method and direct observation with transparent cylinder liner. The visualization of the 3-dimensional calculation gives a good understanding about motion of coolant flow and pressure distribution in water chamber. This method is applied to improve the coolant flow with the stagnation around cylinder liner. The effect of improved design is confirmed by experiment. That is, there are no stagnations in the flow around cylinder liners.