Title of Invention

ATTACHMENT STRUCTURE FOR AN EXHAUST GAS SENSOR FOR AN INTERNAL COMBUSTION ENGINE

Abstract

In an internal combustion engine provided with an engine main unit comprising a cylinder and a cylinder head, an intake port and an exhaust port respectively provided in side surfaces of the cylinder substantially symmetrical with respect to a cylinder axis, and a transmission member housing space for a transmission member driving a cam shaft at as side section where intake and exhaust ports are not provided to the cylinder, to provide a structure for attaching an exhaust gas sensor without the need for a wide space, and without obstructing the transmission member housing space and the exhaust pipe.[Means of Solution] An exhaust pipe extending to the exhaust port extends in a curved manner in a direction opposite to the transmission member housing space close to the exhaust port, with an exhaust gas sensor passing from a wall surface of the cylinder head opposite to the transmission member housing space through the exhaust port being attached[SB2]. [Selected drawing]

Full Text

[Technical Field] [0001] The present invention relates to a structure for attaching an exhaust gas sensor to a cylinder head of an internal combustion engine. [Background Art] [0002] In an internal combustion engine of the related art, an extending direction of an exhaust pipe and attachment position of an exhaust gas sensor are on opposite lateral sides, which means that it becomes possible to expose the exhaust gas sensor underneath when mounting the internal combustion engine on a motorcycle or the like, and it is necessary to carry out work to protect the exhaust gas sensor against flying stones and splashing water from the road surface (for example, refer to patent publication 1). [3] [Patent Publication 1] Published Japanese Patent No. Hei. 3-30702 [Disclosure of the Invention] [Problems to be Solved by the Invention] [4] The present invention provides a structure for attaching an exhaust gas sensor to the periphery of an internal combustion engine, without the need for a wide space for arrangement of the exhaust gas sensor, and that does not interfere with a transmission member housing space or an exhaust pipe. [Means of Solving the Problems] [5] In order to solve the above described problems, the invention disclosed relates to an attachment structure for an exhaust gas sensor of an internal combustion engine, provided with an engine main unit comprising a cylinder and a cylinder head, an intake port and an exhaust port respectively provided in side surface of the cylinder substantially symmetrical with respect to a cylinder axis, and a transmission member housing space for a transmission member driving a cam shaft at as side section where intake and exhaust ports are not provided to the cylinder, wherein an exhaust pipe extending to the exhaust port extends in a curved manner in a direction opposite to the transmission member housing space close to the exhaust port, with an exhaust gas sensor passing from a wall surface of the cylinder head opposite to the transmission member housing space through the exhaust port being attached. A preferred embodiment of the invention discloses an attachment structure for an exhaust gas sensor of an internal combustion engine, wherein the engine main unit comprising a cylinder and a cylinder head extends in a horizontal direction from a crankcase, the exhaust pipe is arranged below the engine main unit, a centerline of the exhaust gas sensor attachment hole faces outwards and is inclined slightly upwards, and the exhaust gas sensor is attached having a rear end wiring section oriented slightly upwards. [7] A preferred embodiment of the invention discloses an attachment structure for an exhaust gas sensor of an internal combustion engine, wherein a secondary air introduction port is provided in the exhaust port, and an exhaust gas detection section of the exhaust gas sensor is positioned at an exhaust port downstream side of an exhaust port side opening of the secondary air introduction port. [8] A preferred embodiment of the invention discloses an attachment structure for an exhaust gas sensor of an internal combustion engine, wherein a secondary air introduction port is provided in the exhaust port, and the exhaust port side opening of the secondary air introduction port is provided opposite an exhaust gas detection section of the exhaust gas sensor. [Effect of the Invention] [9] With the disclosed invention, it is possible to attach an exhaust gas sensor to the periphery of an internal combustion engine without obstructing a transmission member housing space or an exhaust pipe. [10] With the invention disclosed herein, it is possible to reduce water encroaching on sensor wiring constituting a lower position while arranging the exhaust gas sensor compactly in an exhaust port. [0011] With the invention disclosed herein, it is possible to measure components of exhaust gas containing secondary air with a single sensor, and to reduce the number of components. With the invention disclosed herein, since the exhaust port side opening of the secondary air introduction port and an exhaust gas detection section of the exhaust gas sensor are provided on opposite sides to each other, it is possible to make attachment positions of the two close to a combustion chamber side opening section of the exhaust port, and accompanying simplification of exhaust port layout it is possible to improve exhaust gas purification performance. [Preferred Mode of Embodiment the Invention] [13] Fig. 1 is a side elevation of a scooter type motorcycle 1 fitted with an internal combustion engine having an exhaust gas sensor attachment structure of the present invention. With this scooter type motorcycle 1, a head pipe 3 is integrally formed on a front end of a vehicle frame 2, a front fork 4 is mounted on the head pipe 3 so as to be capable of turning left and right, and a front wheel 5 is rotatably attached to a lower end of the front fork 4. A power unit 6 is attached to a rear part of the vehicle frame 2 capable of swinging up and down. This swinging type power unit 6 is integrally comprised of a rocker arm overhead valve type 4- stroke single cylinder water cooled internal combustion engine 7, a transmission unit 8, and a rear wheel support section 9. The rear wheel support section 9 contains a rear wheel 10. Also, a rear suspension 11 is interposed between a rear section of the vehicle frame 2 and a rear section of the power unit 6. A luggage stowing section 12 is provided above and behind the vehicle frame 2, and a seat 13 that opens and closes to cover an upper opening section of this luggage stowing section 12 is also provided. A fuel tank 15 is arranged at a lower section of a step floor at the center of the vehicle. The vehicle frame 2 is covered by a body cover 16. Fig. 2 is a vertical cross sectional drawing of the power unit 6 looking from the side, while Fig. 3 is an expanded drawing of a cross section relating to a plane containing an axis of a cylinder of the power unit 6, a crankshaft, a pulley shaft and a gear shaft. The internal combustion engine 7 of this power unit comprises a. cylinder block 20, a cylinder head 21, a cylinder head cover 22, and a crank case 23, with the cylinder head 21 being coupled to a front end of the cylinder block 20 oriented in a substantially horizontal direction, the cylinder head cover 22 being coupled to a front end of the cylinder head 21, and the crank case 23 being coupled to a rear end of the cylinder block 20. The crank case 23 is made up of left and right crank cases 23A and 23B. In Fig. 2 and Fig. 3, a piston 25 is fitted into a cylinder hole 24 formed in the cylinder block 20 so as to be capable of sliding, and the crankshaft 28 is rotatably supported in bearings 26,27 held in the left and right crank cases 23A and 23B. The two ends of a connecting rod 31 are fitted to the piston 25 and the crank shaft 28 via a piston pin 29 and crank pin 30, and if the piston 25 reciprocates the crank shaft 28 is driven to rotate. [0016] The transmission unit 8 of the power unit 6 is made up of a V-belt type continuously variable transmission 32, and a reduction gear mechanism 33, while a main case of the transmission unit 8 is made up of a right transmission case 40, a left transmission case 41 and a rear wheel support case 42. The right transmission case 40 is manufactured integrally with the left crank case 23A. The left transmission case 41 is coupled to the right transmission case 40, and the rear wheel support case 42 is coupled to the right transmission case 40. [17] A drive shaft of the V-belt type continuously variable transmission 32 is the crankshaft 28, and is provided with a drive pulley 43 of the V-belt type continuously variable transmission 32. A driven shaft 44 of the V-belt type continuously variable transmission 32 is rotatably supported in the right transmission case 40 and the rear wheel support case 42, and a driven pulley 46 of the V-belt type continuously variable transmission 32 is provided on the driven shaft 44 via a centrifugal clutch 45. An endless V-belt 47 is wound around the drive pulley 43 and the driven pulley 46. With the V-belt type continuously variable transmission 32, if the crankshaft 28 rotates faster than a specified rotational speed, the centrifugal clutch 45 is put in an engaged state and the driven shaft 44 starts to rotate. If the rotational speed of the crankshaft 28 increases, the rotational speed of the driven shaft 44 will become faster than the rotational speed of the crankshaft 28 due to a centrifugal force application mechanism of the drive pulley 43. [18] The reduction gear mechanism 33 is constituted by a gear train provided on three rotation shafts. A first shaft is the driven shaft 44 of the V-belt type continuously variable transmission 32 being supported in the right transmission case 40 and the rear wheel support case 42, and is provided with a pinion gear 48. A second shaft is an intermediate shaft 49 being rotatably supported in the right transmission case 40 and the rear wheel support case 42, and as well as having a gear 50 meshing with the pinion gear 48 of the driven shaft integrally fitted, is provided with a pinion gear 51 close to the gear 50[SB1]. A third shaft is a rear wheel axle 52 being rotatably supported by the right transmission case 40 and the rear wheel support case 42, and is fitted with a gear 53 meshing with the pinion gear 51 of the intermediate shaft. The rear wheel 10 is integrally fixed to the rear wheel axle 52. With this structure, torque of the driven shaft 44 is transmitted through the pinion gear 48, gear 50, intermediate shaft 49, pinion gear 51 and gear 53 to the rear wheel axle 52, which means that the rear wheel axle 52 is significantly decelerated compared to the driven shaft 44. [19] Fig. 4 is an enlarged cross sectional drawing of a front section of the internal combustion engine 7, looking from the left. In Fig. 4 Arrow F represents the front of the internal combustion engine, and arrow Up represents up. A combustion chamber 60 is formed in a bottom surface of the cylinder head 21 facing a front end section of the cylinder hole 24 formed in the cylinder block 20, an intake port 61 is formed in an upper part of the cylinder head 21, and an exhaust port 62 is formed in a lower part of the cylinder head 21. An intake valve 63 for opening and closing a combustion chamber side opening 61a of the intake port 61, and an exhaust valve 64 for opening and closing a combustion chamber side opening 62a of the exhaust port 62 are respectively fitted so as to slide in the cylinder head 21. [20] A downstream end of an intake pipe 65 is connected to an outer side opening 61b of the intake port 61. An air cleaner 66 (Fig. 2), a throttle valve 67, and a fuel injection valve 68 are connected in order to this intake pipe 65 from a downstream side. An upstream end of an exhaust pipe 69 is connected to an outer side opening 62b of the exhaust port 62, and a downstream end of the exhaust pipe 69 is connected to a muffler 70 (Fig. 2, Fig. 3). Also, the intake valve 63 and the exhaust valve 64 (Fig. 4) urged in the valve open direction by the valve spring 71 are driven so as to be opened and closed by valve gear 73 arranged inside a valve operating chamber 72 formed by the cylinder head 21 and the cylinder head cover 22. [0021] Fig. 5 is an enlarged horizontal cross-sectional drawing of a front part of the internal combustion engine 7. In Fig. 5, arrow F represents the front of the internal combustion engine, and arrow R represents the right. In Fig. 4 and Fig. 5, a single cam shaft 75 (Fig. 5), positioned inside a V-shaped space (Fig. 4) enclosed by the intake valve 63 and the exhaust valve 64, and oriented in a horizontal direction to the left and right via a pair of left and right bearings 74, is rotatably pivoted. An intake cam 76 and an exhaust cam 77 are integrally formed on the right side and left side of the cam shaft 75. As shown in Fig. 4, an intake rocker shaft 78 positioned further forward and up than the cam shaft 75 is passed through the cylinder head 21 and held so as to rotate, an exhaust rocker shaft 79 positioned below the intake rocker shaft 78 is passed through the cylinder head 21 and held so as to rotate, and an intake rocker arm 80 and an exhaust rocker arm 81 are pivoted on the intake rocker shaft 78 and the exhaust rocker shaft 79 so as to oscillate. Sliding sections 80a and 81a are provided on one end of this intake rocker arm 80 and exhaust rocker arm 81, while contact sections 80b, 81b for contacting apexes of the stems of the intake valve 63 and exhaust valve 64 are provided on the other ends of the intake rocker arm 80 and exhaust rocker aim 81. [0022] A driven sprocket 82 (Fig. 5, Fig. 3) is integrally provided on a left end section of the camshaft 75. A drive sprocket 83 (Fig. 3) having half the number of teeth of the driven sprocket 82 is integrally fitted between a left side crank web 28a of the crankshaft 28 and the previously described drive pulley drive pulley 43. A transmission member housing section 84 connecting the drive sprocket 83 and the driven sprocket 82 is provided at left side sections of the cylinder block 20 and the cylinder head 21, and an endless chain 85 is wound around the drive sprocket 83 and the driven sprocket 82 within this space. The above is the structure of the valve gear 73. If the crankshaft 28 rotates, the camshaft 75 is driven to rotate at half the rotational speed, and the intake valve 63 and the exhaust valve 64 are opened and closed at a specified timing by the intake cam 76 and the exhaust cam 77. [23] Fig. 6 is a drawing looking at an end section of the cylinder head from the front (cross section along line VI - VI in Fig. 5). In Fig. 6, the arrow Up represents above the internal combustion engine, and the arrow R represents to the right. In Fig. 6, a contact surface 21a of the cylinder head 21 on the cylinder block 20 is shown by dots. The intake valve 63 and the exhaust valve 64 can be seen inside the combustion chamber 60. The camshaft 75, driven sprocket 82 and endless chain 85 are inside the transmission member housing section 84 at die left side of the cylinder head 21, and are shown in cross section. [24] In Fig. 5 and Fig. 6, at the right side of the cylinder head, namely a side opposite to the transmission member housing section 84, a spark plug 90 is screwed into a threaded hole 90 in the cylinder head 21, such that an outer end section faces diagonally forward (Fig. 5), and a tip electrode 90a feces into the combustion chamber 60. In Fig. 4, Fig. 5 and Fig. 6, there is an outer opening 62b of the exhaust port 62 at a lower part of the cylinder head 21, and a centerline C of this opening is inclined to the right by about 12° with respect to the vertical V (angle a in Fig. 6). The exhaust pipe 69 is connected to the outer opening 62b of the exhaust port 62. The exhaust pipe 69 extends slightly downwards from the outer opening 62b of the exhaust port 62 (Fig. 4, Fig. 6), then bends abruptly to the right, opposite to the transmission member housing section 84 (Fig. 6) while extending diagonally to the rear (Fig. 5), then bends to the rear (Fig. 4, Fig. 5), before reaching the muffler 70. [26] Fig. 7 is a drawing of the peripheiy of the outer opening 62b of the exhaust port 62, looking from below along the centerline of the outer opening 62b (view along arrowed line VII - VII in Fig. 6). In Fig. 5, Fig. 6 and Fig. 7, an exhaust gas sensor attachment hole 92 is formed from the side in the right side of the exhaust port outer opening 62b in the lower part of the cylinder head 21, namely opposite the transmission member housing section 84. Viewed horizontally (Fig. 5) this exhaust gas sensor attachment hole 92 is substantially orthogonal to the cylinder axis, and when the cylinder is viewed from behind (Fig. 6), the hole is formed in a direction substantially at a right angle with respect to a center lie C of the outer opening 62b of the exhaust port 62. Specifically, the centerline D of the exhaust gas sensor attachment hole 92 is oriented to the right, and inclined slightly upwards. An exhaust gas sensor 93 is fitted into the exhaust gas sensor attachment hole 92 with an exhaust gas detection sensor section 93a at a tip end facing into the exhaust port 62, and with an outer end inclined slightly upwards. An external exposure part of the exhaust gas sensor 93 is positioned just on top of the exhaust pipe 69. As a result, since the exhaust pipe 69, which is very strong, is beneath, the exhaust pipe 69 protects the exhaust gas sensor 93 against contact with and damage from stones and water etc. flying up from the road surface. [0027] In Fig. 6 and Fig. 7, at the left side of the exhaust port 62 a secondary air introduction port 94 of the exhaust port 62 passing to an upstream side of the exhaust gas detection section 93a is provided inclined upwards from a left lower part of the cylinder head 21. The exhaust gas detection section 93a of the exhaust gas sensor that is provided in an exhaust port side opening 92a of the exhaust gas sensor attachment hole is positioned at an exhaust port downstream side of an exhaust port side opening 94a of the secondary air introduction port. The exhaust port side opening 94a of the secondary air introduction port is provided opposite to the exhaust gas detection section 93a of the exhaust gas sensor. This secondary air introduction port 94 is for passing fresh air into the exhaust pipe 69 to make it easy for harmful hydrocarbon (HC) and carbon monoxide (CO) contained in exhaust gas to be burnt and create harmless water (H2O) and carbon dioxide (CO2). [0028] The exhaust gas sensor 93 of this embodiment measures oxygen concentration of a mixture of exhaust gas and fresh secondary air. This measured oxygen concentration value is fed back to an electrical air/fuel ratio controller (not shown) so as to emit exhaust gas that is a clean as possible by controlling a fuel injection amount of the fuel injection valve 68. [29] In Fig. 1, the exhaust gas sensor 93 is attached to a lower part of the internal combustion engine 7, on the opposite side to that shown in the drawing. An electrical cord extends from an outer end of the exhaust gas sensor 93 and is connected to the electrical air fuel ratio controller. In Fig. 1, line G represents the ground surface, and line W is a common tangent of the periphery of the front wheel 5 and a lower end of the fuel tank 15. Generally, when traveling in rain, rain water that has fallen on the ground surface runs as droplets in a direction tangential to the outer periphery of the front wheel 5, and splashes outwards. Within the splashed water drops, drops that have splashed further up than the line W collide with the fuel tank 15 and fall down to the ground surface. Drops that have splashed lower than the line W wet the lower part of the transmission 8 and drop to the ground surface. The exhaust gas sensor 93 of this embodiment is positioned higher up than the line W and behind the fuel tank 15, which means that water splashed from the front wheel 5 is blocked by the fuel tank 15 and does not reach the electrical cord As a result, since feedback control is not obstructed, accurate fuel injection amount control is carried out. [30] As has been described above, in the internal combustion engine of this embodiment, the exhaust pipe connecting to the exhaust port extends to the outside close to the exhaust port then abruptly extends in a curved manner in an opposite direction to the transmission member housing space, an exhaust gas sensor attachment hole is formed passing through to the exhaust port from a cylinder head wall surface opposite to the transmission member housing space, and the exhaust gas sensor is attached at this point, which means that it is possible to attach the exhaust gas sensor around the internal combustion engine without interfering with the transmission member attachment space and the exhaust pipe. Also, with the exhaust pipe below the engine body, the exhaust gas sensor attachment hole is provided passing through from a cylinder side wall of the exhaust pipe above the exhaust port to the exhaust port, and the exhaust gas sensor is attached with a rear end oriented slightly upwards, which means that it is possible to arrange the exhaust gas sensor compactly in the exhaust port Also, the exhaust pipe is provided at a position below the internal combustion engine, but since the exhaust gas sensor is provided above the exhaust pipe it is possible to reduce wetting due to water splashed from the ground surface tangential to the sensor. Also, since the exhaust gas sensor is attached slightly above the rear part of the fuel tank, it is possible to reduce the effect of water splashing from the front wheel. Further, since the exhaust gas detection section of the exhaust gas sensor that is provided in the exhaust port side opening of the exhaust gas sensor attachment hole is positioned at an exhaust port downstream side of the exhaust port side opening of the secondary air introduction port, it is possible to measure components of exhaust gas containing secondary air with a single sensor, and it is possible to reduce the number of components, which is effective. [33] Moreover, because the exhaust port side opening of the secondary air introduction port and the exhaust gas detection section of the exhaust gas sensor are provided on opposite sides to each other, the attachment positions of the two can be made close to the combustion chamber side opening of the exhaust port, and as well as simplifying layout of the exhaust port it is possible to improve exhaust gas purifying performance. [Brief Description of the Drawings] [34] Fig. 1 is a side elevation of a scooter type motorcycle fitted with an internal combustion engine having the exhaust gas sensor attachment structure of the present inventioa Fig. 2 is a cross section of the power unit 6 looking from the side. Fig. 3 is an expanded drawing of a cross section relating to a plane containing an axis of a cylinder of the power unit 6, a crankshaft, a pulley shaft and a gear shaft Fig. 4 is an enlarged cross sectional drawing of a front section of the internal combustion engine 7, looking from the left. Fig. 5 is an enlarged horizontal cross sectional drawing of a front part of the internal combustion engine 7. Fig. 6 is a drawing looking at an end section of the cylinder head from the front (cross section along line VI - VI in Fig. 5). t • > Fig. 7 is a drawing of the periphery of the outer opening 62b of the exhaust port 62, looking from below along the centerline of the outer opening 62b (view along arrowed line VII - VII in Fig. 6). [Description of the Numerals] [0035] 1 scooter type motorcycle 2 vehicle frame 3 head pipe 4 front fork 5 front wheel 6 power unit 7 internal combustion engine 8 transmission unit 9 rear wheel support section 10 rear wheel 11 rear suspension 12 luggage stowing section 13 seat 14 step floor 15 fuel tank 16 body cover 20 cylinder block 21 cylinder head 21a contact surface 22 cylinder head cover 23 crank case 23A left crank case 23B right crank case 24 cylinder hole 25 piston 26 bearing 27 bearing 28 crankshaft 28a 29 30 31 32 33 40 41 42 43 44 45 46 47 48 49 50 51 52 53 60 61 6h 611 62 62j 621 63 64 65 66 67 68 69 70 71 left side crank web piston pin crank pin connecting rod V-belt type continuously variable transmission reduction gear mechanism right transmission case left transmission case rear wheel support case drive pulley driven pulley centrifugal clutch driven pulley endless V-belt pinion gear intermediate shaft gear pinion gear axle gear combustion chamber intake port combustion chamber side opening outer side opening exhaust port combustion chamber side opening outer side opening intake valve exhaust valve intake pipe air cleaner throttle valve fuel injection valve exhaust pipe muffler valve spring 72 valve operating chamber 73 valve gear 74 bearing 75 camshaft 76 intake cam 77 exhaust cam 78 intake rocker shaft 79 exhaust rocker shaft 80 intake rocker arm 80a sliding section 80b contact surface 81 exhaust rocker arm 81a sliding section 81b contact surface 82 driven sprocket 83 drive sprocket 84 transmission member housing space 85 endless chain 90 electrode 91 screw hole for spark plug attachment 92 exhaust gas sensor attachment hole 92a exhaust port side opening of exhaust gas sensor attachment hole 93 exhaust gas sensor 93a exhaust gas detection section 94 secondary air introduction port 94a exhaust port side opening of secondary air introduction port We Claim: 1. An attachment structure for an exhaust gas sensor of an internal combustion engine, provided with an engine main unit (7) that comprises a cylinder (20) and a cylinder head (21), extends forward of a vehicle body from a crankcase (23), and is mounted in a motorcycle (1), an intake port (61) and an exhaust port (62) respectively provided in side surfaces of the cylinder head (21) substantially symmetrical with respect to a cylinder axis, and a transmission member housing space (84) for a transmission member driving a camshaft (75) at a side section where the intake and exhaust ports (61, 62) are not provided to the cylinder head (21), characterized in that an exhaust pipe (69) extending to the exhaust port (62) and extends in a curved manner in a direction opposite to the transmission member housing space (84) close to the exhaust port (62) and is attached to the cylinder head (21); and an exhaust gas sensor (93) passing from a wall surface of the cylinder head (21) opposite to the transmission member housing space (84) through the exhaust port (62) is positioned above the exhaust pipe (69) and attached to the cylinder head (21). 2. The attachment structure for an exhaust gas sensor (93) of an internal combustion engine according to claim 1, wherein the exhaust pipe (69) is arranged below the engine main unit (7), a centerline of an exhaust gas sensor attachment hole (92) faces outwards and is inclined slightly upwards, and the exhaust gas sensor (93) is attached having a rear end wiring section oriented slightly upwards. 3. An attachment structure for an exhaust gas sensor (93) of an internal combustion engine, provided with an engine main unit (7) that comprises a cylinder (20) and a cylinder head (21), extends forward of a vehicle body from a crankcase (23), and is mounted in a motorcycle (1), an intake port (61) and an exhaust port (62) respectively provided in side surfaces of the cylinder head (21) substantially symmetrical with respect to a cylinder axis, and a transmission member housing space (84) for a transmission member driving a camshaft (95) at a side section where the intake and exhaust ports (61,62) are not provided to the cylinder head (21), characterized in that; an exhaust pipe (69) extending to the exhaust port (62) extends in a curved manner in a direction opposite to the transmission member housing space (84) close to the exhaust port (62) and is attached below the engine main unit (7), an exhaust gas sensor (93) passing from a wall surface of the cylinder head (21) opposite to the transmission member housing space (84) through the exhaust port (62) is attached to the cylinder head (21); and the exhaust pipe (69) is arranged below the engine main unit (7), a centerline of an exhaust gas sensor attachment hole (92) faces outwards and is inclined slightly upwards and the exhaust gas sensor (93) is attached having a rear end wiring section oriented slightly upwards. 4. The attachment structure for an exhaust gas sensor (93) of an internal combustion engine according to claim 1 or claim 3, wherein the exhaust gas sensor (93) is attached along the exhaust pipe (69) in a plan view. 5. The attachment structure for an exhaust sensor (93) of an internal combustion engine according to claim 1 or claim 3, wherein an external exposure part of the exhaust gas sensor (93) is positioned above the exhaust pipe (69). 6. The attachment structure for an exhaust gas sensor (93) of an internal combustion engine according to claim 2, wherein a secondary air introduction port (94) is provided in the exhaust port (62) and an exhaust gas deduction section (93a) of the exhaust gas sensor (93) is positioned at an exhaust port downstream side of an exhaust port side opening (94a) of the secondaiy air introduction port (94). 7. The attachment structure for an exhaust gas sensor (93) of an internal combustion engine according to claim 2 or claim 6, wherein the secondary air introduction port (94) is provided in the exhaust port (62) and the exhaust port side opening (94a) of the secondary air introduction port (94) is provided opposite to the exhaust gas deduction section (93a) of the exhaust gas sensor (93).

Documents:

23-CHE-2005 AMENDED PAGES OF SPECIFICATION 30-12-2011.pdf

23-CHE-2005 AMENDED CLAIMS 30-12-2011.pdf

23-CHE-2005 EXAMINATION REPORT REPLY RECEIVED 30-12-2011.pdf

23-CHE-2005 FORM-3 30-12-2011.pdf

23-CHE-2005 OTHER PATENT DOCUMENT 30-12-2011.pdf

23-CHE-2005 POWER OF ATTORNEY 30-12-2011.pdf

23-CHE-2005 ABSTRACT.pdf

23-CHE-2005 CLAIMS.pdf

23-CHE-2005 CORRESPONDENCE OTHERS.pdf

23-CHE-2005 CORRESPONDENCE PO.pdf

23-CHE-2005 DESCRIPTION (COMPLETE).pdf

23-CHE-2005 DRAWINGS.pdf

23-CHE-2005 FORM-1.pdf

23-CHE-2005 FORM-18.pdf

23-CHE-2005 FORM-3.pdf

23-CHE-2005 FORM-5.pdf