Controlling secondary air injection in engine exhaust

Abstract

A solenoid operated valve suitable for controlling flow of air for injection into the exhaust of an engine, the poppet is connected to the solenoid armature in a lost-motion connection. Upon energization, the armature achieves momentum during the lost-motion movement and imports an impulse to the poppet to ensure movement in the event of any tendency of the poppet to stick. A one-way valve prevents exhaust back pressure from opening the poppet.

1 . An electrically operated valve assembly for controlling air injection into the exhaust stream of an internal combustion engine comprising: 
 (a) valve body structure including an inlet port adapted for connection to a source of pressurized air, a valving chamber having a valve seat communicating with the inlet and an outlet port adapted for connection to the exhaust stream;    (b) a one-way valve disposed to permit flow from the valving chamber to the outlet port and prevent flow from the outlet port to the valving chamber;    (c) a valve obturator disposed for movement between a closed position preventing and an open position permitting flow over said valve seat to the outlet port;    (d) an actuator operatively connected to effect the movement of the obturator, the actuator having a portion thereof extending externally of said valving chamber;    (e) a solenoid having an armature moveable upon electrical energization thereof, with the armature operative to effect the movement of the obturator, wherein the armature is disposed for a predetermined limited lost motion movement with respect to the actuator.    
     
     
         2 . The valve assembly defined in  claim 1 , wherein the armature strikes the actuator with an impulse at the end of the limited lost-motion movement.  
     
     
         3 . The valve assembly defined in  claim 1 , wherein the actuator comprises a rod-like member extending through the armature and the obturator.  
     
     
         4 . The valve assembly defined in  claim 1 , wherein the actuator member comprises a rod-like member extending through the armature with one end of the rod-like member enlarged, wherein the amount of the lost-motion movement is determined by the distance between the enlarged end of the rod-like member and the armature when the solenoid is deenergized.  
     
     
         5 . The valve assembly defined in  claim 4 , wherein the actuator has one end extending through the armature and an opposite end extending through the obturator.  
     
     
         6 . A method of controlling air injection into the exhaust stream of an engine comprising: 
 (a) providing a valve body and disposing a valve obturator on a valve seat formed in the body;    (b) connecting an inlet side of the valve seat to an air pump and connecting an outlet side of the valve seat to the exhaust stream;    (c) disposing a one-way valve between the outlet side of the valve seat and the engine exhaust stream and preventing exhaust flow therethrough;    (d) connecting the armature of a solenoid operator to the valve obturator and effecting movement of the obturator upon electrical energization of the solenoid and providing a predetermined limited lost-motion between the solenoid armature and the obturator.    
     
     
         7 . The method defined in  claim 6 , wherein the step of connecting the armature to the obturator includes passing a rod-like member through the armature and connecting an end thereof to the obturator.  
     
     
         8 . The method defined in  claim 6 , wherein the step of connecting the armature to the obturator includes enlarging one end of a rod-like member and passing the remainder through the armature and connecting the end opposite the enlarged end to the obturator.  
     
     
         9 . The method defined in  claim 6 , wherein the step of providing limited lost motion includes disposing the enlarged end of the rod-like member for limited lost motion with respect to the armature.