Exhaust gas purifying apparatus for automobile multi-cylinder engine

摘要

An exhaust gas purifying apparatus, for use in an automobile multi-cylinder engine of the type which has exhaust port ducts leading from engine cylinders and through which exhaust gases are emitted subsequent to combustion of an air-fuel mixture, the exhaust gas purifying apparatus having a reducing catalyst unit and an oxidizing catalyst unit disposed in a main exhaust manifold which is corrected on one side, to a first group of the exhaust port ducts and, on the other side to the atmosphere, an auxiliary exhaust manifold is connected, on one side to a second group of the exhaust port ducts and on the other side to a portion of the main exhaust manifold which is downstream from the reducing catalyst unit and upstream of the oxidizing catalyst unit. A pressure operated valve is disposed on a secondary air supply passage for introducing secondary air into the auxiliary exhaust manifold by the utilization of a pulsating flow of the exhaust gases through the auxiliary exhaust manifold, and an exhaust gas recirculating system extending between the main exhaust manifold to an intake system of the engine.