Exhaust manifold of dual type formed with chamber to receive exhaust gas

Abstract

An exhaust manifold for a multicylinder internal combustion engine which may be an automotive engine. The manifold is of the dual type having a wall formed in the interior to serve as a partition between two separate exhaust gas passages which are communicable with first and second groups of engine cylinders, respectively. To enable installation of an exhaust gas sensor in the manifold, the partition wall has a generally cup-shaped portion which provides therein a chamber to receive the sensitive part of the sensor. The cylindrical side wall of the cup-shaped portion is formed with at least two fairly narrow apertures which provide fluid communication between the inner chamber and the two exhaust gas passages, respectively. In operation, small fractions of the exhaust gases flowing in the two separate passages enter the sensor chamber in the cup-shaped portion of the partition wall to enable detection of an average concentration of a specific component, e.g. oxygen, of the separately flowing exhaust gases without causing substantial mixing or interference of the two exhaust gas flows with each other.