Exhaust apparatus for transverse engine

Abstract

Disclosed is an exhaust apparatus (E) for a transverse engine ( 1 ) coupled with a transmission ( 11 ) located on one side thereof in a cylinder arrangement direction. The exhaust apparatus (E) has an upstream exhaust assembly ( 48 ) which comprises a plurality of branch pipe portions ( 32 ), a single exhaust pipe portion ( 34 ), and an exhaust gas-purifying unit ( 40 ). The exhaust gas-purifying unit ( 40 ) is disposed on a vehicle-rear side of the engine ( 1 ) to allow a gas passage thereinside to extend approximately in a vehicle-widthwise direction, in top plan view. The upstream exhaust assembly ( 48 ) includes, on an exhaust upstream side of the single exhaust pipe portion ( 34 ), a section which curves to allow an exhaust downstream region of the section to be oriented toward one side of the vehicle-widthwise direction which is a direction coming close to the transmission ( 11 ), in top plan view. The single exhaust pipe portion ( 34 ) curves to allow an exhaust downstream region of the single exhaust pipe portion ( 34 ) to be oriented toward a vehicle-front side, in top plan view. This makes it possible to compactly lay out the upstream exhaust assembly ( 48 ) in an engine compartment ( 19 ) without sacrificing a passenger compartment space, and quickly raise a temperature of a catalyst in the exhaust gas-purifying unit ( 40 ) during warm-up of the engine ( 1 ).

1 . An exhaust apparatus provided in an engine having a plurality of cylinders arranged in a line, wherein the engine is transversely placed in an engine compartment at a front of a vehicle to allow a cylinder arrangement direction to be oriented in a vehicle-widthwise direction, and coupled with a transmission located on one side thereof in the cylinder arrangement direction, the exhaust apparatus comprising an upstream exhaust assembly connected to a surface of the engine on a vehicle-rear side, and a downstream exhaust pipe provided on an exhaust downstream side of the upstream exhaust assembly, wherein the upstream exhaust assembly includes:
 a plurality of branch pipe portions communicated with respective ones of the plurality of cylinders and extending from the vehicle-rear-side surface of the engine toward the vehicle-rear side;   a single exhaust pipe portion provided on the exhaust downstream side of the plurality of branch pipe portions in such a manner that it is communicated with the branch pipe portions; and   an exhaust gas-purifying unit connected to an exhaust downstream end of the single exhaust pipe portion,   and wherein:   the exhaust gas-purifying unit is disposed on the vehicle-rear side of the engine to allow a gas passage thereinside to extend approximately in the vehicle-widthwise direction, in top plan view;   the upstream exhaust assembly includes, on an exhaust upstream side of the single exhaust pipe portion, a section which curves to allow an exhaust downstream region of the section to be oriented toward one side of the vehicle-widthwise direction which is a direction coming close to the transmission, in top plan view;   the single exhaust pipe portion curves to allow an exhaust downstream region of the single exhaust pipe portion to be oriented toward a vehicle-front side, in top plan view; and   the downstream exhaust pipe is connected to an exhaust downstream end of the exhaust gas-purifying unit, and disposed to extend from a connection portion thereof with the exhaust gas-purifying unit toward an tunnel opening formed in a vehicle-widthwise central region of a lower end of a dash panel of the vehicle.   
     
     
         2 . The exhaust apparatus as defined in  claim 1 , wherein:
 the exhaust gas-purifying unit has a catalyst installation portion formed in a cross-sectionally generally circular shape and provided in the gas passage; and   a maximum vehicle-widthwise protruding amount of the single exhaust pipe portion with respect to an exhaust upstream end surface of the catalyst installation portion is set to be greater than a maximum vehicle-widthwise protruding amount of the downstream exhaust pipe with respect to an exhaust downstream end surface of the catalyst installation portion, to allow a gas entry angle with respect to the exhaust upstream end surface of the catalyst installation portion to become greater than a gas discharge angle with respect to the exhaust downstream end surface of the catalyst installation portion.   
     
     
         3 . The exhaust apparatus as defined in  claim 2 , wherein the exhaust gas-purifying unit is disposed on the vehicle-front side of an exhaust upstream end of the single exhaust pipe portion and below the branch pipe portions. 
     
     
         4 . The exhaust apparatus as defined in  claim 3 , wherein:
 the exhaust gas-purifying unit is supported with respect to the engine; and   the downstream exhaust pipe has a flexible joint interposed therein.   
     
     
         5 . The exhaust apparatus as defined in  claim 4 , wherein:
 the upstream exhaust assembly has a plurality of intermediate collector pipe portions between each of the plurality of branch pipe portions and the single exhaust pipe portion;   each of the intermediate collector pipe portions is formed by dividing the plurality of cylinders into a plurality of cylinder groups each consisting of two or more cylinders whose exhaust strokes are not successive with respect to each other, and merging the branch pipe portions communicated with respective ones of the cylinders in each of the cylinder groups, on a cylinder group-by-cylinder group basis;   the single exhaust pipe portion is formed by merging the plurality of intermediate collector pipe portions together; and   each of the plurality of intermediate collector pipe portions curves to allow an exhaust downstream region of the intermediate collector pipe portion to be oriented toward one side of the vehicle-widthwise direction which is a direction coming close to the transmission, in top plan view.   
     
     
         6 . The exhaust apparatus as defined in  claim 4 , wherein:
 the section of the upstream exhaust assembly on the exhaust upstream side of the single exhaust pipe portion is comprised of the branch pipe portions;   the single exhaust pipe portion is formed by merging the plurality of branch pipe portions together; and   each of the plurality of branch pipe portions curves to allow an exhaust downstream region of the branch pipe portion to be oriented toward one side of the vehicle-widthwise direction which is a direction coming close to the transmission, in top plan view.   
     
     
         7 . The exhaust apparatus as defined in  claim 1 , wherein the exhaust gas-purifying unit is disposed on the vehicle-front side of an exhaust upstream end of the single exhaust pipe portion and below the branch pipe portions. 
     
     
         8 . The exhaust apparatus as defined in  claim 7 , wherein:
 the exhaust gas-purifying unit is supported with respect to the engine; and   the downstream exhaust pipe has a flexible joint interposed therein.   
     
     
         9 . The exhaust apparatus as defined in  claim 1 , wherein:
 the upstream exhaust assembly has a plurality of intermediate collector pipe portions between each of the plurality of branch pipe portions and the single exhaust pipe portion;   each of the intermediate collector pipe portions is formed by dividing the plurality of cylinders into a plurality of cylinder groups each consisting of two or more cylinders whose exhaust strokes are not successive with respect to each other, and merging the branch pipe portions communicated with respective ones of the cylinders in each of the cylinder groups, on a cylinder group-by-cylinder group basis;   the single exhaust pipe portion is formed by merging the plurality of intermediate collector pipe portions together; and   each of the plurality of intermediate collector pipe portions curves to allow an exhaust downstream region of the intermediate collector pipe portion to be oriented toward one side of the vehicle-widthwise direction which is a direction coming close to the transmission, in top plan view.   
     
     
         10 . The exhaust apparatus as defined in  claim 1 , wherein:
 the section of the upstream exhaust assembly on the exhaust upstream side of the single exhaust pipe portion is comprised of the branch pipe portions;   the single exhaust pipe portion is formed by merging the plurality of branch pipe portions together; and   each of the plurality of branch pipe portions curves to allow an exhaust downstream region of the branch pipe portion to be oriented toward one side of the vehicle-widthwise direction which is a direction coming close to the transmission, in top plan view.   
     
     
         11 . The exhaust apparatus as defined in  claim 2 , wherein:
 the upstream exhaust assembly has a plurality of intermediate collector pipe portions between each of the plurality of branch pipe portions and the single exhaust pipe portion;   each of the intermediate collector pipe portions is formed by dividing the plurality of cylinders into a plurality of cylinder groups each consisting of two or more cylinders whose exhaust strokes are not successive with respect to each other, and merging the branch pipe portions communicated with respective ones of the cylinders in each of the cylinder groups, on a cylinder group-by-cylinder group basis;   the single exhaust pipe portion is formed by merging the plurality of intermediate collector pipe portions together; and   each of the plurality of intermediate collector pipe portions curves to allow an exhaust downstream region of the intermediate collector pipe portion to be oriented toward one side of the vehicle-widthwise direction which is a direction coming close to the transmission, in top plan view.   
     
     
         12 . The exhaust apparatus as defined in  claim 2 , wherein:
 the section of the upstream exhaust assembly on the exhaust upstream side of the single exhaust pipe portion is comprised of the branch pipe portions;   the single exhaust pipe portion is formed by merging the plurality of branch pipe portions together; and   each of the plurality of branch pipe portions curves to allow an exhaust downstream region of the branch pipe portion to be oriented toward one side of the vehicle-widthwise direction which is a direction coming close to the transmission, in top plan view.   
     
     
         13 . The exhaust apparatus as defined in  claim 3 , wherein:
 the upstream exhaust assembly has a plurality of intermediate collector pipe portions between each of the plurality of branch pipe portions and the single exhaust pipe portion;   each of the intermediate collector pipe portions is formed by dividing the plurality of cylinders into a plurality of cylinder groups each consisting of two or more cylinders whose exhaust strokes are not successive with respect to each other, and merging the branch pipe portions communicated with respective ones of the cylinders in each of the cylinder groups, on a cylinder group-by-cylinder group basis;   the single exhaust pipe portion is formed by merging the plurality of intermediate collector pipe portions together; and   each of the plurality of intermediate collector pipe portions curves to allow an exhaust downstream region of the intermediate collector pipe portion to be oriented toward one side of the vehicle-widthwise direction which is a direction coming close to the transmission, in top plan view.   
     
     
         14 . The exhaust apparatus as defined in  claim 3 , wherein:
 the section of the upstream exhaust assembly on the exhaust upstream side of the single exhaust pipe portion is comprised of the branch pipe portions;   the single exhaust pipe portion is formed by merging the plurality of branch pipe portions together; and   each of the plurality of branch pipe portions curves to allow an exhaust downstream region of the branch pipe portion to be oriented toward one side of the vehicle-widthwise direction which is a direction coming close to the transmission, in top plan view.