Airflow control valve for use in an internal combustion engine

Abstract

An airflow control valve is composed of a housing forming an air passage therein and an electromagnetically driven valve disposed in the air passage. The valve divides the air passage into an upstream passage having an air inlet port and a downstream passage having an outlet port open to an exhaust pipe. A barrier facing an exhaust gas blown back from the exhaust pipe is formed in the downstream passage in order to reduce an amount of deposits accumulating on and around the valve due to foreign particles contained in the exhaust gas. The barrier may be a dead end space in which the exhaust gas stagnates or a wall interfering with a flow of the exhaust gas. A one-way valve may be disposed immediately downstream of the valve to prevent the exhaust gas from flowing toward the valve.

1 . An airflow control valve for use in an internal combustion engine, the airflow control valve comprising: 
 a housing forming an air passage therein;    a valve disposed in the air passage for opening or closing the air passage, the air passage being separated by the valve into an upstream passage having an inlet port and a downstream passage having an outlet port from which air is blown out, the outlet port being open to a source of exhaust gas exhausted from the internal combustion engine; and    a barrier disposed in the down stream passage to face the outlet port for reducing an amount of the exhaust gas directly hitting the valve when the exhaust gas enters the downstream passage from the outlet port.    
   
   
       2 . The airflow control valve as in  claim 1 , wherein: 
 the barrier includes a passage surface facing the outlet port; and    a stagnating space for stagnating the exhaust gas flow is formed in the vicinity of the passage surface.    
   
   
       3 . An airflow control valve for use in an internal combustion engine, the airflow control valve comprising: 
 a housing forming an air passage therein;    a valve disposed in the air passage for opening or closing the air passage, the air passage being separated by the valve into an upstream passage having an inlet port and a downstream passage having an outlet port from which air is blown out, the outlet port being open to a source of exhaust gas exhausted from the internal combustion engine; and    a dead end space disposed in the downstream passage to face the outlet port for stagnating the exhaust gas entering into the downstream passage from the outlet port, the dead end space having an opening from which the exhaust gas enters.    
   
   
       4 . The airflow control valve as in  claim 3 , wherein: 
 the dead end space includes a passage surface facing the outlet port, and the opening of the dead end space open to the passage surface.    
   
   
       5 . The airflow control valve as in  claim 3 , wherein: 
 the opening of the dead end space is smaller than an inside of the dead end space.    
   
   
       6 . The airflow control valve as in  claim 3 , wherein: 
 a bent portion for preventing foreign particles, contained in the exhaust gas, once entered into the dead end space from bouncing out of the dead end space is formed at the opening of the dead end space.    
   
   
       7 . The airflow control valve as in  claim 6 , wherein: 
 the bent portion is formed at a portion of the opening close to the valve.    
   
   
       8 . An airflow control valve for use in an internal combustion engine, the airflow control valve comprising: 
 a housing forming an air passage therein;    a valve disposed in the air passage for opening or closing the air passage, the air passage being separated by the valve into an upstream passage having an inlet port and a downstream passage having an outlet port from which air is blown out, the outlet port being open to a source of exhaust gas exhausted from the internal combustion engine; and    an interfering wall disposed in the downstream passage for interfering with a flow of the exhaust gas entering into the downstream passage from the outlet port.    
   
   
       9 . The airflow control valve as in  claim 8 , wherein: 
 the interfering wall includes a wall surface directly facing the outlet port; and    a stagnating space for stagnating the exhaust gas therein is formed between the wall surface and the outlet port.    
   
   
       10 . The airflow control valve as in  claim 9 , wherein: 
 the downstream passage includes passage surfaces inclined along a flow direction of the air to be blown out from the outlet port so that the air smoothly flows through the downstream passage.    
   
   
       11 . The airflow control valve as in  claim 1 , wherein: 
 the upstream passage is a passage for introducing compressed secondary air to be supplied to an exhaust pipe of the internal combustion engine;    the downstream passage is a passage for supplying the air to the exhaust pipe of internal combustion engine; and    the valve is a valve for controlling an amount of the secondary air to be supplied to the exhaust pipe of the engine by opening or closing the air passage.    
   
   
       12 . The airflow control valve as in  claim 11 , wherein: 
 a one-way valve for preventing the exhaust gas from entering into the upstream passage is provided in the downstream passage.    
   
   
       13 . The airflow control valve as in  claim 12 , wherein: 
 the one-way valve includes a metal plate having air passages through which the secondary air flows, a reed valve for opening or closing the air passages, and a reed valve stopper for limiting an opening degree of the reed valve; and    the one-way valve is positioned in the vicinity of the valve.    
   
   
       14 . The airflow control valve as in  claim 1 , wherein: 
 the air passage is a passage for connecting an exhaust pipe to an intake pipe of the internal combustion engine for re-circulating part of the exhaust gas to the engine for decreasing a combustion temperature in the engine, and an amount of the exhaust gas to be re-circulated is controlled by the valve.