On cold start operation of a gasoline engine, a catalyst shows poor performance before it reaches activation temperature. Therefore, fast warmup of the catalyst is very crucial to reduce harmful emissions. In this study, an appropriate control strategy is investigated to increase exhaust gas temperature through changes of exhaust valve timing. An advance of exhaust valve timing decreases residual gas in cylinders due to decrease of valve overlap period. A control strategy of proper valve timing is suggested in order to achieve fast light-off of the catalyst and stable operation of the engine in a cold start and idle operation.

The Dry Continuously Variable Transmission (CVT) consists of a driving pulley and a driven pulley joined by a rubber V-belt. An each pulley consists of a fixed flange and a movable flange. The movable flange of the driving pulley has the centrifugal roller and a ramp plate in the flange. The movable flange moves toward a fixed flange under the actuation of a centrifugal roller, as the driving pulley speed increases. In this study, the function and the relationship of the all parts in the Dry CVT are investigated. The profile of movable flange is analyzed. The effect of axial force is also analyzed by speed ratio and load torque.

This study aims to establish complementary relationship among designer, builder, and maintenance manager by combining BIM(Building Information Modeling) technology with bridge safety diagnosis and maintenance to secure its effectiveness and systematization. To establish and maintain database by organizing quantities of data about existing case of safety diagnosis and maintenance, and develop the system to be used by practitioners.