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Airflow control valve for use in an internal combustion engineRelated Patent Categories: Power Plants, Internal Combustion Engine With Treatment Or Handling Of Exhaust Gas, By Means Producing A Chemical Reaction Of A Component Of The Exhaust Gas, Condition Responsive Control Of Reactor Feed, Pressure, Or By-pass, Air Feed To Reactor Modulated Or Diverted By ControlAirflow control valve for use in an internal combustion engine description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20060037310, Airflow control valve for use in an internal combustion engine. Brief Patent Description - Full Patent Description - Patent Application Claims
CROSS-REFERENCE TO RELATED APPLICATION [0001] This application is based upon and claims benefit of priority of Japanese Patent Application No. 2004-240955 filed on Aug. 20, 2004, the content of which is incorporated herein by reference. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates to an airflow control valve for opening or closing an air passage communicating with an exhaust gas passage in an internal combustion engine, and more particularly to an airflow control valve for controlling an amount of secondary air supplied from an air pump to an exhaust pipe. [0004] 2. Description of Related Art [0005] Examples of an airflow control valve for supplying secondary air to a three-way catalyzer in an exhaust pipe for raising temperature of the three-way catalyzer when an engine is being started are disclosed in JP-A-2002-272080 and JP-A-2002-260919. The airflow control valve disclosed therein includes an electromagnetic valve and a one-way valve. An essential portion of the airflow control valve is shown in FIG. 10 attached hereto. [0006] As shown in FIG. 10, the electromagnetic valve 102 contained in a valve housing 104 is composed of a valve 106 for opening or closing an opening 105 formed in the valve housing, a solenoid actuator for driving the valve 106 in a direction to open the opening 105, and a coil spring 107 for biasing the valve 106 in a direction to close the opening 105. The one-way valve 103 is disposed at a boundary portion connecting the valve housing 104 and an outlet casing 110. The one-way valve 103 is composed of a reed valve 112 for opening or closing an opening 111 formed in a metal plate 114 and a reed stopper 113 for protecting the reed valve 112. [0007] Air pressurized by an air pump (not shown) is introduced into the valve housing 104, and the introduced air is supplied to a three-way catalyzer (not shown) in an exhaust pipe through an air passage shown with white arrows when the valve 106 opens the opening 105. The one-way valve 103 is opened by the air passing through the air passage and is closed by exhaust gas (shown with dotted arrows in FIG. 10) blown back from the exhaust pipe. The blown back exhaust gas that includes unburned gas, carbon particles and other small particles is prevented from entering into the valve housing 104 by the one-way valve 103. [0008] In the conventional airflow control valve, however, following problems are involved. When the valve 106 is closed, exhaust gas is blown back due to pulsating pressure of the engine and enters into the outlet casing 110 as shown with dotted arrows in FIG. 10. Small particles contained in the exhaust gas adhere to the reed valve 112, forming deposits thereon. If the deposits are formed between the metal plate 114 and the reed valve 112, the reed valve 112 becomes unable to close, and the exhaust gas enters into valve housing 104 containing the valve 106 therein. In other words, the reed valve 112 becomes unable to function as the one-way valve for preventing the exhaust gas from being blown back into the valve housing 104. The deposits may be formed on the valve 106 and the valve seat. If this happens, movement of the valve 106 is hindered, and the valve 106 may not be smoothly opened. As a result, the secondary air cannot be sufficiently supplied to the three-way catalyzer. [0009] An exhaust gas control valve is conventionally used in an exhaust gas re-circulation system. In this system, part of the exhaust gas is introduced into an air-intake pipe of an engine to reduce an amount of nitrogen-oxides formulated in combustion by lowering a combustion temperature. The re-circulating exhaust gas is supplied to the intake pipe through the exhaust gas control valve. The exhaust gas control valve is composed of a housing forming an exhaust gas passage therein, a valve for closing or opening the exhaust gas passage, and a coil spring biasing the valve in the closing direction. The valve is driven by a motor actuator in the opening direction. [0010] Small particles contained in the exhaust gas adhere to the valve and the valve seat in the exhaust gas control valve, forming deposits around the valve. To reduce an amount of deposits accumulated around the valve, an exhaust gas recirculation valve having a side hole in the passage for accumulating the deposits therein is proposed in JP-A-2002-339811. However, the small particles in the exhaust gas once entered into the side hole are highly possible to bounce out into the passage. Therefore, much effect cannot be expected for the proposed side hole. SUMMARY OF THE INVENTION [0011] The present invention has been made in view of the above-mentioned problem, and an object of the present invention is to provide an improved airflow control valve, in which an amount of deposits accumulating on a control valve and a one-way valve is reduced. [0012] The airflow control valve has an air passage and an electromagnetically driven valve disposed in the air passage. The air passage is divided into two passages by the valve, i.e., an upstream passage having an inlet port and a downstream passage having an outlet port. Secondary air compressed by an air pump is introduced into the upstream passage through the inlet port and supplied from the downstream passage to an exhaust pipe of an internal combustion engine through the outlet port. An amount of air supplied to the exhaust pipe is controlled by opening or closing the valve. The outlet port is open to the exhaust pipe, and exhaust gas is blown back into the downstream passage. [0013] A barrier facing the outlet port from which the exhaust gas enters into the airflow control valve is disposed in the downstream passage to reduce an amount of the exhaust gas directly hitting the valve. Thus, an amount of deposits accumulating on and around the valve due to foreign particles contained in the exhaust gas is reduced. The barrier may be made in a form of a dead end space having a small opening facing the outlet port. The exhaust gas entering into the airflow control valve stagnates in the dead end space, and some foreign particles are kept therein. To prevent the foreign particles once kept in the dead end space from bouncing out of the dead end space toward the valve, bent portions may be made at the opening of the dead end space. An interfering wall directly facing the outlet port may be made in the downstream passage to form a stagnating space between the interfering wall and the outlet port. [0014] Preferably, one-way valve for preventing the exhaust gas from entering into the upstream passage while permitting the secondary air to flow therethrough is disposed immediately downstream of the valve. The valve is prevented from being directly hit by the exhaust gas blown back from the exhaust pipe. The one-way valve is also protected from being directly hit by a large amount of the exhaust gas by the barrier, the dead end space or the interfering wall disposed in the downstream passage. [0015] The airflow control valve may be used as a valve for controlling an amount of exhaust gas to be re-circulated from an exhaust pipe into an intake pipe of an engine. In this case, the exhaust gas is introduced from the outlet port, and the inlet port is connected to the intake pipe of the engine. [0016] According to the present invention, an amount of exhaust gas directly hitting the valve and the one-way valve is reduced and an amount of deposits accumulating on and around the valve and the one-way valve is reduced. Accordingly, the airflow control valve can be operated without being hindered by accumulation of deposits. Other objects and features of the present invention will become more readily apparent from a better understanding of the preferred embodiments described below with reference to the following drawings. BRIEF DESCRIPTION OF THE DRAWINGS [0017] FIG. 1 is a cross-sectional view showing an airflow control valve as a first embodiment of the present invention; [0018] FIG. 2 is a cross-sectional view showing the same airflow control valve as shown in FIG. 1, including arrows showing flow directions of air and exhaust gas; [0019] FIG. 3 is a cross-sectional view showing an airflow control valve as a second embodiment of the present invention; [0020] FIG. 4 is a cross-sectional view showing an airflow control valve as a third embodiment of the present invention; Continue reading about Airflow control valve for use in an internal combustion engine... Full patent description for Airflow control valve for use in an internal combustion engine Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Airflow control valve for use in an internal combustion engine patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. Start now! - Receive info on patent apps like Airflow control valve for use in an internal combustion engine or other areas of interest. ### Previous Patent Application: Fuel vaporizing device Next Patent Application: Secondary air supply for engine exhaust system Industry Class: Power plants ### FreshPatents.com Support Thank you for viewing the Airflow control valve for use in an internal combustion engine patent info. 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