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To reduce cold-start emissions that is a bottleneck of tightened regulation, a photocatalyst was suggested and studied. Conventional TWC can reduce more than 96% of harmful emissions after the activation, but under a cold-start condition it needs a lot of energy to activate. During the activation time (light-off time) harmful gases are exhausted without any purification and it makes the conventional TWC difficult to satisfy tightened regulation. A photocatalyst can be activated by light that has wavelengths lower than 380 nano-meters. The activation needs no time and loss of energy like a TWC. To apply the photocatalyst on a vehicle aftertreatment a photocatalyst system was suggested that uses non-thermal plasma as a light source of photocatalyst. The durability of a photocatalyst was also studied with hydrothermal aging method. The properties of aged catalyst were tested with surface area, phase transformation and conversion efficiency of HC.

In this study, feasibility tests of secondary air injection technology and lean A/F control technology were performed for LEV program using the FTP75 test on a 2.0 DOHC A/T vehicle. Second-by-second emissions and temperatures were evaluated. The temperatures of exhaust gas were measured at exhaust manifold, front of warm up, and the center of warm up converter. At first, amount of secondary air injection was determined with a bench aged warm up converter and a fresh UCC. And then, the performances of secondary air injection and lean A/F control strategy were compared with 80,000km vehicle aged converters(warm up converter, UCC). Both secondary air injection and lean A/F control technologies satisfied the ULEV regulation. This study shows that the lean A/F control strategy can be one of the potential technologies to meet the LEV/ULEV regulations without an active system that need a cost up.

A mixed lubrication model based on the average Reynolds equation has been used so far for the tribological analysis of a piston ring assembly. In this study, a simplified average Reynolds equation is applied for mixed lubrication analysis of a ring assembly. The tedious numerical procedure and computing time required for the modeling and analysis was significantly reduced by introducing a contact factor to replace the average gap that includes the asperity contact between two lubricated surfaces. It was observed that this model appropriately reflects mixed lubrication characteristic or piston ring from the qualitative analysis.

A modified version of KIVA-II code is applied to scavenging flow simulation of a four-poppet-valved two-stroke engine. The standard k-ε turbulence model is used with no slip on the wall. Grid is generated through direct interface with three dimensional CAD data using a commercial CAE package. Valve motion is taken into account by identifying the cells occupied by the valve structure and putting them as solid obstacle cells. Results show reasonable trends for variation of the velocity field and fresh air mass fraction distribution with crank angle. Parametric study shows that the intake port orientation does not have much effect on the cylinder flow and scavenging efficiency due to strong flow diversion by the valves.

The tests on running engines reveal that the vibration levels of an engine block are higher at the lower portion than the upper portion. The objective of this paper is to reduce the vibration levels of an engine block by the stiffening plates with minimum weight increase. The analytical modal analyses of an engine block and the stiffening plates made of aluminum and steel are performed by the Finite Element Method (FEM). The experimental modal analyses are also conducted and two results are correlated. In these validated modal model, an engine block and the stiffening plates are combined by the spring elements. The Component Mode Synthesis is used to obtain the natural frequencies and modes of the combined blocks. The iterative analyses are performed with varying thickness of the stiffening plates in order to design the optimum one which reduces the vibration levels of an engine block effectively with minimum weight increase.

Piston motion affects the thermal efficiency of an internal combustion engine. The efficiency loss due to piston motion is defined as time loss, and accounts for 6 - 7 % of the total loss in a spark ignition engine. In this paper, an analysis is made of the time loss for a conventional slider-crank engine and a perfectly sinusoidal piston motion engine. The heat release rate is modeled using test data from an 1.6 / OHC engine, and parametric studies are made to identify factors affecting thermal efficiencies of engines with conventional and unconventional piston motions.