Internal combustion engine exhaust cooling system

Abstract

An internal combustion engine exhaust cooling system includes an exhaust gas cooling adapter that is arranged between an exhaust port that opens in a cylinder head, and an exhaust branch pipe, and cools exhaust gas that flows through an exhaust passage by running coolant through a coolant passage formed inside of a wall that surrounds the exhaust passage. The coolant passage includes a first passage and a second passage being provided according to an offset of an amount of heat received from exhaust gas in a circumferential direction of an inner surface of the exhaust passage, and two middle passages that connect the first passage with the second passage at both ends of the two middle passages, and a coolant delivery direction is a direction from the second passage side of a first middle passage, of the two middle passages, toward the first passage side.

1 . An internal combustion engine exhaust cooling system comprising:
 an exhaust gas cooling adapter that is arranged between an exhaust port that opens in a cylinder head, and an exhaust branch pipe, and cools exhaust gas that flows through an exhaust passage by running coolant through a coolant passage formed inside of a wall that surrounds the exhaust passage,   wherein the exhaust gas cooling adapter includes a coolant inlet that introduces coolant into the coolant passage, and a coolant outlet that discharges coolant outside from the coolant passage;   the coolant passage includes a first passage that is on a high heat receiving side and a second passage that is on a low heat receiving side, the first passage and the second passage being provided according to an offset of an amount of heat received from exhaust gas in a circumferential direction of an inner surface of the exhaust passage, and two middle passages that connect the first passage with the second passage at both ends of the two middle passages;   a coolant delivery direction of the coolant inlet is a direction from the second passage side of a first middle passage, of the two middle passages, toward the first passage side; and   the coolant outlet discharges coolant from a location where a second middle passage, of the two middle passages, is connected with the first passage, or from near the location.   
     
     
         2 . The internal combustion engine exhaust cooling system according to  claim 1 , wherein the first middle passage is located closer to the coolant inlet than the second middle passage is. 
     
     
         3 . The internal combustion engine exhaust cooling system according to  claim 1 , wherein the coolant outlet discharges coolant in the same direction as a flow direction of coolant in the first passage. 
     
     
         4 . The internal combustion engine exhaust cooling system according to  claim 1 , wherein a plurality of the exhaust ports are provided;
 each of the plurality of exhaust ports is arranged and open in a cylinder head;   a plurality of the exhaust passages are formed in an arrangement inside the exhaust gas cooling adapter,   the arrangement of the plurality of exhaust passages corresponding to an arrangement of the plurality of exhaust ports; and   
       the exhaust ports are formed curved in a direction orthogonal to an arrangement direction of the exhaust passages, or the exhaust ports and the exhaust passages are connected bent in a direction orthogonal to the arrangement direction. 
     
     
         5 . The internal combustion engine exhaust cooling system according to  claim 4 , wherein the arrangement direction of the exhaust ports in the cylinder head is a horizontal direction, and the direction orthogonal to the arrangement direction is vertically downward. 
     
     
         6 . The internal combustion engine exhaust cooling system according to  claim 1 , wherein a plurality of the exhaust ports are provided;
 each of the plurality of exhaust ports is arranged and open in a cylinder head; a plurality of the exhaust passages are formed in an arrangement inside the exhaust gas cooling adapter,   the arrangement of the plurality of exhaust passages corresponding to an arrangement of the plurality of exhaust ports;   the exhaust ports are formed curved in a direction orthogonal to an arrangement direction of the exhaust passages, or the exhaust ports and the exhaust passages are connected bent in a direction orthogonal to the arrangement direction;   the coolant inlet delivers coolant from the second passage toward the first passage via a middle passage on one end side in the arrangement direction; and   the coolant outlet discharges coolant from a location where a middle passage on the other end side in the arrangement direction is connected to the first passage, or from near the location.   
     
     
         7 . The internal combustion engine exhaust cooling system according to  claim 1 , wherein a flow direction guide that guides a flow of coolant delivered from the coolant inlet to a first middle passage, of the two middle passages, is provided in the coolant passage, in a location near the coolant inlet. 
     
     
         8 . An internal combustion engine exhaust cooling system comprising:
 an exhaust gas cooling adapter that is arranged between an exhaust port that opens in a cylinder head, and an exhaust branch pipe, and cools exhaust gas that flows through an exhaust passage by running coolant through a coolant passage formed inside of a wall that surrounds the exhaust passage,   wherein the exhaust gas cooling adapter includes a coolant inlet that introduces coolant into the coolant passage, and a coolant outlet that discharges coolant outside from the coolant passage;   the coolant passage includes an outside passage of a curve and an inside passage of a curve that are provided according to a curve in an exhaust flow produced by a curved shape of the exhaust port, and two middle passages that connect the outside passage with the inside passage at both ends of the two middle passages;   a coolant delivery direction of the coolant inlet is a direction from the inside passage side of a first middle passage, of the two middle passages, toward the outside passage side; and   the coolant outlet discharges coolant from a location where a second middle passage, of the two middle passages, is connected with the outside passage, or from near the location.   
     
     
         9 . The internal combustion engine exhaust cooling system according to  claim 8 , wherein the first middle passage is located closer to the coolant inlet than the second middle passage. 
     
     
         10 . The internal combustion engine exhaust cooling system according to  claim 8 , wherein the exhaust passage is bent with respect to the exhaust port. 
     
     
         11 . The internal combustion engine exhaust cooling system according to  claim 8 , wherein the coolant outlet discharges coolant in the same direction as a flow direction of coolant in the outside passage. 
     
     
         12 . The internal combustion engine exhaust cooling system according to  claim 8 , wherein a plurality of the exhaust ports are provided;
 each of the plurality of exhaust ports is arranged and open in a cylinder head;   a plurality of the exhaust passages are formed in an arrangement inside the exhaust gas cooling adapter,   the arrangement of the plurality of exhaust passages corresponding to an arrangement of the plurality of exhaust ports; and   the exhaust ports are formed curved in a direction orthogonal to an arrangement direction of the exhaust passages, or the exhaust ports and the exhaust passages are connected bent in a direction orthogonal to the arrangement direction.   
     
     
         13 . The internal combustion engine exhaust cooling system according to  claim 12 , wherein the arrangement direction of the exhaust ports in the cylinder head is a horizontal direction, and the direction orthogonal to the arrangement direction is vertically downward. 
     
     
         14 . The internal combustion engine exhaust cooling system according to  claim 8 , wherein a plurality of the exhaust ports are provided;
 each of the plurality of exhaust ports is arranged and open in a cylinder head;   a plurality of the exhaust passages are formed in an arrangement inside the exhaust gas cooling adapter,   the arrangement of the plurality of exhaust passages corresponding to an arrangement of the plurality of exhaust ports;   the exhaust ports are formed curved in a direction orthogonal to an arrangement direction of the exhaust passages, or the exhaust ports and the exhaust passages are connected bent in a direction orthogonal to the arrangement direction;   the coolant inlet delivers coolant from the inside passage toward the outside passage via a middle passage on one end side in the arrangement direction; and   the coolant outlet discharges coolant from a location where a middle passage on the other end side in the arrangement direction is connected to the outside passage, or from near the location.   
     
     
         15 . The internal combustion engine exhaust cooling system according to  claim 8 , wherein a flow direction guide that guides a flow of coolant delivered from the coolant inlet to a first middle passage, of the two middle passages, is provided in the coolant passage, in a location near the coolant inlet. 
     
     
         16 . An internal combustion engine exhaust cooling system comprising:
 an exhaust gas cooling adapter that is arranged between an exhaust port that opens in a cylinder head, and an exhaust branch pipe, and cools exhaust gas that flows through an exhaust passage by running coolant through a coolant passage formed inside of a wall that surrounds the exhaust passage,   wherein the exhaust gas cooling adapter includes a coolant inlet that introduces coolant into the coolant passage, and a coolant outlet that discharges coolant outside from the coolant passage;   the coolant passage includes an outside passage of a curve and an inside passage of a curve that are provided according to a curve in an exhaust flow produced by a bent shape of a connecting portion between the exhaust port and the exhaust passage, and two middle passages that connect the outside passage with the inside passage at both ends of the two middle passages;   a coolant delivery direction of the coolant inlet is a direction from the inside passage side of a first middle passage, of the two middle passages, toward the outside passage side; and   
       the coolant outlet discharges coolant from a location where a second middle passage, of the two middle passages, is connected with the outside passage, or from near the location. 
     
     
         17 . The internal combustion engine exhaust cooling system according to  claim 16 , wherein the first middle passage is located closer to the coolant inlet than the second middle passage. 
     
     
         18 . The internal combustion engine exhaust cooling system according to  claim 16 , wherein a plurality of the exhaust ports are provided;
 each of the plurality of exhaust ports is arranged and open in a cylinder head;   a plurality of the exhaust passages are formed in an arrangement inside the exhaust gas cooling adapter,   the arrangement of the plurality of exhaust passages corresponding to an arrangement of the plurality of exhaust ports; and   
       the exhaust ports are formed curved in a direction orthogonal to an arrangement direction of the exhaust passages, or the exhaust ports and the exhaust passages are connected bent in a direction orthogonal to the arrangement direction. 
     
     
         19 . The internal combustion engine exhaust cooling system according to  claim 18 , wherein the arrangement direction of the exhaust ports in the cylinder head is a horizontal direction, and the direction orthogonal to the arrangement direction is vertically downward. 
     
     
         20 . The internal combustion engine exhaust cooling system according to  claim 16 , wherein a plurality of the exhaust ports are provided;
 each of the plurality of exhaust ports is arranged and open in a cylinder head;   a plurality of the exhaust passages are formed in an arrangement inside the exhaust gas cooling adapter, the arrangement of the plurality of exhaust passages corresponding to an arrangement of the plurality of exhaust ports;   the exhaust ports are formed curved in a direction orthogonal to an arrangement direction of the exhaust passages, or the exhaust ports and the exhaust passages are connected bent in a direction orthogonal to the arrangement direction;   the coolant inlet delivers coolant from the inside passage toward the outside passage via a middle passage on one end side in the arrangement direction; and   
       the coolant outlet discharges coolant from a location where a middle passage on the other end side in the arrangement direction is connected to the outside passage, or from near the location. 
     
     
         21 . The internal combustion engine exhaust cooling system according to  claim 16 , wherein a flow direction guide that guides a flow of coolant delivered from the coolant inlet to a first middle passage, of the two middle passages, is provided in the coolant passage, in a location near the coolant inlet.