MULTI-STAGE CATALYTIC SYSTEM IN CONTROLLED AUTO-IGNITION GASOLINE ENGINE AND CONTROL METHOD THEREOF, COMPRISING CASE, THREE WAY CATALYST, OXIDATION CATALYST, FIRST AND SECOND VALVES, AND CONTROLLER

摘要

PURPOSE: A multi-stage catalytic system in a controlled auto-ignition gasoline engine and a control method thereof are provided to reduce exhaust pressure of an exhaust system and to improve the engine output, by selectively passing exhaust gas thorough a three-dimensional catalyst or an oxidation catalyst according to an operation mode of the gasoline engine. CONSTITUTION: A multi-stage catalytic system in a controlled auto-ignition gasoline engine comprises a case(10); a three-dimensional catalyst(20) having a passage(22) formed to the middle part to bypass exhaust gas; an oxidation catalyst(30) having a passage(32) arranged to the middle part to bypass exhaust gas; a first valve(24) opening and shutting the passage formed to the three-dimensional catalyst; a second valve(34) opening and shutting the passage formed to the oxidation catalyst; and a controller controlling the first and second valves. The three-dimensional catalyst is arranged in the exhaust gas inlet(12) side of the case. The oxidation catalyst is arranged in the exhaust gas outlet(14) side of the case.