Vehicle exhaust system structure

Abstract

A vehicle exhaust system structure is obtained which can protect well a bend portion of an exhaust pipe. A vehicle exhaust system structure 10 is intended to discharge exhaust gases of a front-engine front-drive vehicle with a transverse engine from a rear part of a vehicle body and is applied to an exhaust system 11 which is configured such that a first catalytic converter 12 , a second catalytic converter 14 , an exhaust system heat exchanger 15 and a muffler 16 are disposed sequentially in that order from an upstream side in an exhaust gas flow direction. In the exhaust system 11 , a heat exchanger to muffler exhaust pipe 26 which connects the exhaust system heat exchanger 15 to the muffler 16 has an inclined portion 26 A, and a portion of the exhaust system 11 which lies further rearwards than the exhaust system heat exchanger 15 is suspended from the vehicle body by a suspension unit 80 . Provided on a catalytic converter to heat exchanger exhaust pipe 24 which connects the second catalytic converter 14 to the exhaust system heat exchanger 15 is a ball joint 96 which permits a relative displacement between the second catalytic converter 14 and the exhaust system heat exchanger 15.

1 . A vehicle exhaust system structure for discharging exhaust gases of an internal combustion engine, which is transversely installed in a front part of a vehicle body, from a rear part of the vehicle body, the vehicle exhaust system structure comprising:
 a first catalytic device, a second catalytic device, an exhaust heat recovery unit and a silencer which are disposed sequentially in that order from an upstream side in an exhaust gas flow direction;   a first exhaust pipe which connects the second catalytic device to the exhaust heat recovery unit;   a second exhaust pipe which includes a portion extending in a direction intersecting a vehicle front-rear direction and, which connects the exhaust heat recovery unit, which is disposed to be offset in a vehicle width direction, to the silencer;   a suspension unit which suspends at least part of the exhaust system elements including the exhaust heat recovery unit, the second exhaust pipe, and the silencer, relative to the vehicle body, on a downstream side in an exhaust gas flow direction relative to the first exhaust pipe; and   a vibration cut-off mechanism which is provided at the first exhaust pipe and permits a relative displacement between the second catalytic device and the exhaust heat recovery unit.   
   
   
       2 . The vehicle exhaust system structure according to  claim 1 , wherein
 the first catalytic device, the second catalytic device, the first exhaust pipe and the exhaust heat recovery unit are disposed linearly along a vehicle front-rear direction when seen in plan view,   the vibration cut-off mechanism is configured such that a front portion and a rear portion of the first exhaust pipe in the vehicle front-rear direction may be displaced relative to each other in a vehicle vertical direction.   
   
   
       3 . The vehicle exhaust system structure according to  claim 1 , wherein
 the suspension unit has a heat recovery unit suspending portion which suspends the exhaust heat recovery unit relative to the vehicle body, and which is at a position furthest upstream in an exhaust gas flow direction, and wherein   the heat recovery unit suspending portion includes a supported member which is fixed to a low-rigidity portion of the exhaust heat recovery unit.   
   
   
       4 . The vehicle exhaust system structure according to  claim 2 , wherein
 the suspension unit has a heat recovery unit suspending portion which suspends the exhaust heat recovery unit relative to the vehicle body, and which is at a position furthest upstream in an exhaust gas flow direction, and wherein   the heat recovery unit suspending portion includes a supported member which is fixed to a low-rigidity portion of the exhaust heat recovery unit.   
   
   
       5 . The vehicle exhaust system structure according to  claim 1 , further comprising:
 a vibration cut-off mechanism which permits a relative displacement between the first catalytic device and the second catalytic device.   
   
   
       6 . The vehicle exhaust system structure according to  claim 2 , further comprising:
 a vibration cut-off mechanism which permits a relative displacement between the first catalytic device and the second catalytic device.   
   
   
       7 . The vehicle exhaust system structure according to  claim 3 , further comprising:
 a vibration cut-off mechanism which permits a relative displacement between the first catalytic device and the second catalytic device.   
   
   
       8 . The vehicle exhaust system structure according to  claim 4 , further comprising:
 a vibration cut-off mechanism which permits a relative displacement between the first catalytic device and the second catalytic device.   
   
   
       9 . The vehicle exhaust system structure according to  claim 1 , wherein
 a bend portion of the second exhaust pipe is made up of a shell which is formed at one end of the exhaust heat recovery unit, and an inclined portion of the second exhaust pipe which extends in a direction intersecting the vehicle front-rear direction.   
   
   
       10 . The vehicle exhaust system structure according to  claim 9 , wherein
 the shell includes a projecting portion which projects in a direction in which the inclined portion extends, further than an end surface of the shell in a vehicle width direction.   
   
   
       11 . A vehicle exhaust system structure for discharging exhaust gases of an internal combustion engine, which is transversely installed in a front part of a vehicle body, from a rear part of the vehicle body, the vehicle exhaust system structure comprising:
 a first catalytic device, a second catalytic device, an exhaust heat recovery unit and a silencer which are disposed sequentially in that order from an upstream side in an exhaust gas flow direction;   an exhaust pipe which includes a portion extending in a direction intersecting a vehicle front-rear direction, and which connects the exhaust heat recovery unit, which is disposed to be offset in a vehicle width direction, to the silencer;   a vibration cut-off mechanism which permits a relative displacement between the first catalytic device and the second catalytic device, or a relative displacement between the second catalytic device and the exhaust heat recovery unit; and   a suspension unit which includes a supported member which is fixed to a low-rigidity portion of the exhaust heat recovery unit and a support member which supports the supported member on the vehicle body.   
   
   
       12 . The vehicle exhaust system structure according to  claim 11 , wherein
 a bend portion of the exhaust pipe is made up of a shell which is formed at one end of the exhaust heat recovery unit, and an inclined portion of the exhaust pipe which extends in a direction intersecting the vehicle front-rear direction.   
   
   
       13 . The vehicle exhaust system structure according to  claim 12 , wherein
 the shell includes a projecting portion which projects in a direction in which the inclined portion extends, further than an end surface of the shell in a vehicle width direction.