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Emission of carbon dioxide from mobile sources seriously concerned to solve greenhouse effect and high price of gasoline in some countries have resulted in the development of lean-burn concept engine. In spite of many studies on the lean deNOx catalyst, we have no clear solution to obtain high fuel economy and high efficiency of NOx conversion in lean-burn application. This paper describes applicability and problems of NOx adsorber system to partial lean-burn vehicle, the development of three-way catalyst with improvement of washcoat technology based on three-way catalyst used for gasoline application, and comparison test results of evaluations is synthesized gas activity test, Federal Test Procedure (FTP) test, etc. This study shows improved three-way catalysts in partial lean- burn vehicle have max. 89% of NOx conversion in FTP without adding rich spike and regeneration functions to engine management system.

Effects of the copper infiltration and the oxide formation on the wear behavior of the sintered exhaust valve seat material were investigated by the pin - on - disc wear test. By the copper infiltration, the wear properties were remakably improved, on the contrast, the oxide deteriorated the wear resistance. The friction coefficient and specific wear rate decreased with the applied load. The dominant wear mechanism was suggested as follows; the spalling of the bulk debris in the non-infiltrated sample and the mild oxidational wear in the infiltrated.