Vehicle exhaust device

1. A vehicle exhaust device comprising:

a plurality of exhaust passage forming units forming an exhaust passage from at least one exhaust port provided at an engine body to an exhaust muffler provided behind the engine body; and

an exhaust gas sensor attached to a portion of the exhaust passage forming units halfway on the exhaust passage, wherein

at least a portion of the exhaust gas sensor is covered from a front side thereof with the portion of the exhaust passage forming units upstream of an attached position of the exhaust gas sensor,

the engine body includes a crankcase, and

the exhaust gas sensor is disposed in front of a front surface of the crankcase, a forward direction of the vehicle corresponding to a front direction of the vehicle exhaust device,

wherein the portion of the exhaust passage forming units upstream of an attached position of the exhaust gas sensor extends in an extending direction of the exhaust gas sensor in a front view.

2. The vehicle exhaust device according to claim 1 , wherein

the engine body includes a plurality of cylinders,

the plurality of exhaust passage forming units includes a plurality of individual exhaust pipes connected respectively to the exhaust ports of the cylinders and a collecting pipe collecting downstream ends of the plurality of individual exhaust pipes, and

the exhaust gas sensor is attached to the collecting pipe.

3. The vehicle exhaust device according to claim 2 , wherein

the plurality of individual exhaust pipes includes two pipes, each pipe having downstream connections disposed in parallel with each other, and the exhaust gas sensor is positioned between the two connections when viewed in a direction perpendicular to a plane including axial lines of the connections.

4. The vehicle exhaust device according to claim 2 , wherein

the collecting pipe has a front end connected to lower ends of the individual exhaust pipes and positioned above the attached position of the exhaust gas sensor.

5. The vehicle exhaust device according to claim 2 , wherein

the collecting pipe includes:

a downstream rear portion disposed close to a lower front end of the engine body and provided anteroposteriorly;

a curved portion connected to a front end of the rear portion and curved upward; and

an upstream front portion extending from an upper end of the curved portion to the lower ends of the individual exhaust pipes.

6. The vehicle exhaust device according to claim 2 , wherein

the exhaust gas sensor protrudes radially outward from the collecting pipe,

the downstream connections of the individual exhaust pipes covering the exhaust gas sensor from the front side thereof extend in an extending direction of the exhaust gas sensor in a front view.

7. The vehicle exhaust device according to claim 2 , wherein

the collecting pipe is disposed at a position deviating to one side in a vehicle width direction from a center in the vehicle width direction, and

the outward protrusion of the exhaust gas sensor slants outward in the vehicle width direction toward an upper end.

8. The vehicle exhaust device according to claim 2 , wherein

the exhaust gas sensor is disposed in front of the engine body, and

the rear portion of the collecting pipe is disposed below the engine body.

9. The vehicle exhaust device according to claim 2 , further comprising:

a guard covering the exhaust gas sensor from a lateral side thereof in the vehicle width direction.

10. The vehicle exhaust device according to claim 2 , wherein

the individual exhaust pipes are disposed in front of the engine body and have exposed front ends.

11. The vehicle exhaust device according to claim 2 , wherein

the collecting pipe is disposed at a position deviating to one side in a vehicle width direction from a center in the vehicle width direction,

the individual exhaust pipes are disposed in front of the engine body, and

the individual exhaust pipes each have a downstream portion covering the exhaust gas sensor from the front side thereof and slanting outward in the vehicle width direction toward an upper end.

12. The vehicle exhaust device according to claim 2 , wherein

the exhaust gas sensor is detachably connected by screwing to an attachment portion provided on the collecting pipe.

13. The vehicle exhaust device according to claim 2 , wherein

the exhaust gas sensor and a lower end connection of the individual exhaust pipe extend upward to slant in the vehicle width direction at substantially a same angle in a front view.

14. The vehicle exhaust device according to claim 2 , wherein

a front portion of the collecting pipe covers the exhaust gas sensor from the front side thereof.

15. The vehicle exhaust device according to claim 1 , wherein

the engine body has a front surface provided with an oil filter protruding forward,

the exhaust gas sensor is disposed at a position deviating to one side in the vehicle width direction from the oil filter, and

the outward protrusion of the exhaust gas sensor slants away in the vehicle width direction from the oil filter toward the upper end.

16. The vehicle exhaust device according to claim 1 , wherein

the exhaust gas sensor is entirely covered from a front side thereof with the portion of the exhaust passage forming units upstream of an attached position of the exhaust gas sensor.

17. A vehicle exhaust device comprising:

a plurality of exhaust passage forming units forming an exhaust passage from at least one exhaust port provided at an engine body to an exhaust muffler provided behind the engine body; and

an exhaust gas sensor attached to a portion of the exhaust passage forming units halfway on the exhaust passage, wherein

the exhaust gas sensor is entirely covered from a front side thereof with the portion of the exhaust passage forming units upstream of an attached position of the exhaust gas sensor, a forward direction of the vehicle corresponding to a front direction of the vehicle exhaust device.