Internal combustion engine having a cylinder head and a secondary air system

Abstract

An internal combustion engine has a cylinder head having an integrated exhaust manifold which has multiple exhaust ducts; and a secondary air system for supplying ambient air that is additionally supplied through an inlet as secondary air into the exhaust manifold into the exhaust gas flow downstream from the exhaust valves of the internal combustion engine during the cold-start phase. For fresh air supply, the secondary air system has a plurality of supply ducts that connect a distributor block of the secondary air system to an exhaust duct and are arranged in the integrated exhaust manifold and each provided with a valve assembly. Each valve assembly has a blocking means in the form of a closure flap that is pivotable about a pivot axis at a distance from the center of mass of the blocking means. According to the installation position of the internal combustion engine in a motor vehicle, and owing to this eccentric arrangement of the pivot axis, the blocking means assumes a defined closed position under the influence of gravity when there is no pressure difference between the exhaust manifold and the secondary air system and opens automatically under the influence of a relative overpressure in the gas pressure on the side of the secondary air system in relation to the gas pressure on the side of the exhaust manifold.

Dependencies are inferred from the claim text.