Single valve intake/exhaust device for a direct injection internal combustion engine

Abstract

An intake and exhaust device for an internal combustion engine with direct injection comprises an intake and exhaust valve ( 11 ) with a stem ( 13 ), a head ( 12 ), and a seat ( 24 ) facing a combustion chamber (CC) of the engine (M), an intake duct ( 42 ) for the intake of air into the combustion chamber (CC), and an exhaust duct ( 38, 57 ) for the discharge of the exhaust gases, the exhaust duct ( 38, 57 ) being connected to the intake duct ( 42 ) upstream of the valve seat ( 24 ). The exhaust duct ( 38, 57 ) is arranged so as to be coaxial with the valve ( 11 ) and the intake duct ( 42 ) extends radially. The connection between the intake duct and the exhaust duct ( 38, 57 ) is in the vicinity of the seat ( 24 ) of the valve ( 11 ) so that the exhaust gas-flow conveyed through the connection has a radial velocity component directed towards the valve stem ( 13 ). The air is drawn in from the intake duct ( 42 ) as a result of the gas-flow passing through the exhaust duct ( 38, 57 ) during the exhaust phase and as a result of the movement of a piston (P) in the cylinder during the intake phase.

1 . An intake and exhaust device for an internal combustion engine (M) with direct injection, comprising an intake and exhaust valve ( 11 ) with a stem ( 13 ) and a head ( 12 ), the seat ( 24 ) of which faces a combustion chamber (CC) of a cylinder (C) of the engine (M), at least one intake duct ( 42 ) for the intake of air into the combustion chamber (CC), and one exhaust duct ( 38 ,  57 ) for the discharge of the exhaust gases, the exhaust duct ( 38 ,  57 ) being connected to the intake duct ( 42 ) upstream of the valve seat ( 24 ), wherein the exhaust duct ( 38 ,  57 ) is arranged so as to be substantially coaxial with the valve ( 11 ) and the at lease one intake duct ( 42 ) extend substantially radially, the connection with the exhaust duct ( 38 ,  57 ) being arranged in the vicinity of the seat ( 24 ) of the valve ( 11 ) in a manner such that the exhaust gas-flow conveyed through the connection has a radial velocity component directed towards the stem ( 13 ) of the valve ( 11 ) so that the air is drawn in from the intake duct ( 42 ) as a result of the gas-flow passing through the exhaust duct ( 38 ,  57 ) during the exhaust phase and as a result of the movement of a piston (p) into the cylinder (C) during the intake phase, characterized in that at least one annular disc-like element ( 30 ) with a central opening ( 33 ) is arranged around the exhaust duct ( 38 ,  57 ) in the region of the connection with the intake duct ( 42 ) to promote the mixing of the air drawn in with the exhaust gases.  
   
   
       2 . A device according to  claim 1  in which at least a portion of the exhaust duct ( 38 ,  57 ) has a cross-section which increases progressively in the direction away from the valve seat ( 24 ).  
   
   
       3 . A device according to  claim 1 , wherein the at least one intake duct ( 42 ) is defined by a casing element ( 40 ) arranged around the valve ( 11 ) and provided with a plurality of air-inlet slots ( 41 ) arranged radially in the walls of the casing ( 40 ).  
   
   
       4 . A device according to  claim 1  in which a plurality of annular disc-like elements ( 30 ) are arranged along the exhaust duct ( 38 ,  57 ) in a manner such that their respective central openings ( 33 ) are aligned coaxially.  
   
   
       5 . A device according to  claim 4  in which the central openings ( 33 ) have cross-sections which increase in the direction away from the seat ( 24 ) of the valve ( 11 ).  
   
   
       6 . A device according to  claim 1 , wherein the intake duct ( 42 ) comprises deflector means ( 34 ) which are suitable for conveying the exhaust gas-flow through the exhaust duct ( 38 ,  57 ) and which are arranged in the region of the connection of the intake duct with the exhaust duct ( 38 ,  57 ).  
   
   
       7 . A device according to  claim 6  in which the deflector means are formed on a rim ( 34 ) of the central opening ( 33 ) of each annular disc-like element ( 30 ).  
   
   
       8 . A device according to  claim 7  in which the deflector means comprise a rim ( 34 ) of the central opening ( 33 ) of each annular disc-like element ( 30 ), which rim is curved or bent in the direction of the exhaust gas-flow through the exhaust duct ( 38 ,  57 ).  
   
   
       9 . A deviced according to  claim 1 , wherein a plurality of radial ribs ( 28 ,  56 ) for preventing gas turbulence are arranged inside the exhaust duct ( 38 ,  57 ), extending along the length of the exhaust duct ( 38 ,  57 ).  
   
   
       10 . A device according to  claim 9  in which the radial ribs ( 56 ) also extend in the intake duct ( 42 ).  
   
   
       11 . An internal combustion engine, comprising the device according to  claim 1 .  
   
   
       12 . (Canceled)