Secondary air supply system for internal combustion engine

Abstract

The present specification discloses a system for providing a secondary air supply to an internal combustion engine so as to reduce undesirable exhaust gases. The system includes a hose running from a region of higher pressure to the exhaust port of the engine so as to supply air to such port. The area of higher pressure preferably comes from either a forward portion of the vehicle or from a high pressure region within the clutch compartment of the engine. A one-way valve is provided adjacent the exhaust port to eliminate any back flow. The method of providing secondary air supply is also disclosed.

Description

FIELD OF THE INVENTION [0001] This invention relates generally to emission control systems for internal combustion engines and, more specifically, to a secondary air supply system for an engine. BACKGROUND OF THE INVENTION [0002] Systems have been developed to supply additional air to the hot exhaust gases of an internal combustion engine in order to reduce carbon monoxide and hydrocarbon emissions. Systems, such as that described in U.S. Pat. No. 6,382,197 to Matsumoto, employ a secondary air valve apparatus that pulls air from the air cleaner. The air is fed to the exhaust port—drawn by negative pressure created at the port when the combustion-chamber exhaust valves are closed. The additional air combined with the high temperatures present at the exhaust port helps complete combustion of unburned hydrocarbons and reacts with the carbon monoxide present to produce carbon dioxide. [0003] The exhaust gases are emitted in pulses, controlled by the exhaust valves as spent fuel from a c...

AI Technical Summary

Benefits of technology

[0006] The present invention provides a secondary air supply to the hot exhaust of an internal combustion engine without expensive, complex control devices and bulky components. Installation on vehicles, such as all-terrain vehicles (ATVs), is simplified, effective, and inexpensive.

[0012] The present invention provides the advantages of simplicity and cost effectiveness. An auxiliary pump is not necessary to increase the pressure of the air that is fed to the exhaust port. The system is also small and easy to arrange in position since it is mainly comprised of a hose; the reed valve preferably being the only moving part. The secondary air supply assists the engine by creating lower emissions of noxious gases including hydrocarbons and carbon monoxide without adding significant weight or complication.

Problems solved by technology

Such systems are bulky and costly and may not adequately provide a pressure differential to supply adequate air for most efficient emissions cleaning without a separate air pump or loss of power.

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