Patent ID: 8806868

Claim:
A method for secondary air injection to exhaust passages of an internal combustion engine comprising: directing combustion gases from the internal combustion engine to a first exhaust passage of an exhaust manifold of the internal combustion engine and a second exhaust passage of the exhaust manifold; injecting air from a first conduit into the first exhaust passage in fluid communication with a first set of cylinders, forming a first exhaust mixture; injecting air from a second conduit into the second exhaust passage in fluid communication with a second set of cylinders, forming a second exhaust mixture; controlling injecting air from the first conduit into the first exhaust passage and the second conduit to the second exhaust passage to inject air to at least one of the first and second conduits during an engine startup period and to stop air injection after an engine warm up period, wherein the first conduit and second conduit are attached to and in fluid communication with a cylinder head of the internal combustion engine, the first conduit and second conduit being located outside of the cylinder head and not in fluid communication with each other; delivering the first exhaust mixture from the first conduit to a the turbocharger; and delivering the second exhaust mixture from the second conduit to the turbocharger, wherein the first exhaust mixture from the first conduit is separated from the second exhaust mixture from the second conduit and the exhaust-gas flow in the first exhaust passage is out of phase with the exhaust-gas flow in the second exhaust passage.