Patent ID: 8429896

Claim:
An internal combustion engine comprising: a cylinder; an exhaust conduit coupled to the cylinder and receiving exhaust emissions from the cylinder; a blower housing; a secondary air conduit coupling an inner region within the blower housing to an orifice on the exhaust conduit, wherein the secondary air conduit receives air from the inner region and communicates the air to the orifice, the air being directed through the blower housing by a fan that directs at least some additional air to proceed out the blower housing and around one or more engine components so as to cool the one or more engine components, and wherein the air communicated to the orifice is mixed with the exhaust emissions and, due to an exothermic oxidation reaction, results in a reduction in at least one component of the exhaust emissions; a first valve assembly associated with the secondary air conduit, wherein the first valve assembly at least partially governs a flow of the air through the secondary air conduit to the orifice on the exhaust conduit, wherein the first valve assembly is implemented within the blower housing, wherein the first valve assembly includes a one-way valve that is a reed valve, wherein a reed of the reed valve has a length ranging from about 20 millimeters to about 50 millimeters, wherein the reed has a width ranging from about 10 millimeters to about 20 millimeters, and wherein the reed has a thickness ranging from about 0.05 millimeters to about 0.3 millimeters; and a muffler coupled to the exhaust conduit, wherein the muffler operates at a back pressure ranging from 22.1 to 62 inches of water at the rated power, wherein the muffler has a size selected to achieve a volume ratio, VR, which is a volume of the muffler divided by a cylinder displacement, ranging from about 3 to about 10, wherein the engine does not include any catalytic converter, and wherein the engine is a small off-road engine.