JP2001041076A - Exhaust gas sensor attaching structure of motorcycle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively use a space and sufficiently secure the capacity of an oil pan by attaching an exhaust gas sensor on any one of two front collecting pipes of an engine exhauster in which four exhaust pipes are collected to two front collecting pipes and further collected by one rear collecting pipe. SOLUTION: An exhaust gas sensor 33 is attached to a left front collecting pipe 31L out of right and left front collecting pipes 31L of an engine exhauster 22 in which four exhaust pipes 23a to 23d extending from the front surface of an engine 16 are collected by two front collecting pipes 31L and further collected by one rear collecting pipe 32. The left front collecting pipe 31L having the exhaust gas sensor 33 is arranged on the opposite side to a clutch device with respect to the center of a vehicle body, and the exhaust gas sensor 33 is arranged in such a position as to not interfere the flat shape of the oil pan 30 in plan view. Therefore, a space under the engine 16 can be effectively used, and the capacity of the oil pan 30 can be sufficiently secured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas sensor mounting structure for a motorcycle.

[0002]

From the purification problems of the exhaust gas discharged from an engine mounted to the prior art motorcycle or the like, in order to improve the control accuracy of the combustion O _{2 (oxygen)} sensor or A / F (air-fuel ratio) or the like of the sensor It is desired to install an exhaust gas sensor.

Examples of the installation of these exhaust gas sensors include, for example, Japanese Patent Application Laid-Open No. 58-152116 and
As shown in JP-A-26375, a catalyst is disposed in a portion of an exhaust pipe extending downward from the front of the engine and extending rearward, for example, at a position below or below the engine, and an exhaust gas sensor is provided immediately before the catalyst. There is an example where is arranged.

[0004] In the case of a multi-cylinder engine, there is a type in which a plurality of exhaust gas sensors are arranged in each exhaust pipe.

[0005]

However, if the exhaust gas sensor is arranged at the above-mentioned position, the exhaust gas sensor may interfere with an oil pan provided at a lower portion of the engine, and the shape of the oil pan is changed. as a result,
The capacity of the oil pan cannot be secured sufficiently.

Further, if the exhaust gas sensor is disposed at the above-mentioned position, the exhaust gas sensor may be damaged when the motorcycle falls, which is not preferable.

Further, in the case of a multi-cylinder engine, if an exhaust gas sensor is provided for each exhaust pipe, the number of parts increases, leading to an increase in cost.

The present invention has been made in consideration of the above circumstances, and has as its object to provide an exhaust gas sensor mounting structure for a motorcycle that reduces the number of parts and costs.

Another object of the present invention is to provide a motorcycle exhaust gas sensor mounting structure in which the space below the engine can be used effectively, the capacity of the oil pan can be sufficiently ensured, and damage at the time of falling can be prevented. is there.

[0010]

According to a first aspect of the present invention, there is provided an exhaust gas sensor mounting structure for a motorcycle, comprising four exhaust pipes extending from a front surface of an engine. The two front collecting pipes are once gathered once by two, and furthermore, these front collecting pipes are gathered together by one rear collecting pipe. An exhaust gas sensor is attached to one of the front collecting pipes.

According to another aspect of the present invention, the engine includes a crankshaft extending in a vehicle width direction of the vehicle body, a flywheel magneto device provided at one end thereof, A clutch device is provided at an end, a front collecting pipe for mounting the exhaust gas sensor is disposed on the opposite side of the clutch device with respect to the center of the vehicle body, and the exhaust gas sensor is provided below the engine in plan view. It is arranged at a position that does not interfere with the planar shape of the oil pan to be used.

Further, in order to solve the above-mentioned problems,
As described in claim 3, the exhaust gas sensor is disposed behind a magneto cover that covers the flywheel magneto device in a side view, and the exhaust gas sensor is substantially aligned with an extension of a bank angle formed by the vehicle body during banking. They are arranged in parallel.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a left side view showing an example of a motorcycle to which the present invention is applied. As shown in FIG. 1, the motorcycle 1 has a body frame 2, and a head pipe 3 is provided in front of the body frame. The head pipe 3 is provided with a suspension mechanism (not shown), and a steering mechanism 6 including a pair of left and right front forks 5 for rotatably supporting the front wheel 4 is provided.

On the other hand, the body frame 2 is of, for example, a twin tube type, and after being expanded right and left immediately after the head pipe 3, a pair of left and right tank rails 7 extending parallel to each other and obliquely downward and rearward. It comprises a pair of left and right center frames 8 connected to the rear end of the tank rail 7 and extending substantially vertically, and a pair of right and left seat rails 9 extending rearward from the upper rear end of the center frame 8.

Above the tank rail 7 is a fuel tank 10
The operation seat 11 is provided above the seat rail 9.
Is arranged. A pivot shaft 12 is provided at the lower center of the center frame 8, and a swing arm 13 is pivotally mounted on the pivot shaft 12 so as to swing around the pivot shaft 12. A rear wheel 14 is rotatably supported at the rear end of the swing arm 13.

Further, the motorcycle 1 has a front portion of the vehicle body 1 covered with a streamlined cowling 15 to reduce air resistance during traveling and protect a rider from traveling wind pressure.

FIG. 2 is a left side view of the central portion of the vehicle body 1 with the cowling 15 removed. As shown in FIGS. 1 and 2, an engine 16 is disposed below the fuel tank 10 in the lower center of the vehicle body 1. The engine 16 is, for example, a water-cooled parallel four-cylinder engine, and has a cylinder assembly 17 integrally provided with four cylinders (cylinders) not shown.
Are arranged in the width direction of the vehicle body 1 in a state of being slightly inclined forward on the upper part of the crankcase 18. A radiator 19 for cooling the engine is disposed below the head pipe 3 and in front of the engine 16.

A fuel supply device 20 is connected to the rear upper portion of the cylinder assembly 17 and an air cleaner 21 is connected to an upstream side thereof. Also, the cylinder assembly 17
The exhaust pipes 23a to 23d constituting the engine exhaust device 22 are connected to the front of the engine, and the muffler 24 is connected to the downstream side thereof.

FIG. 3 is a view taken in the direction of the arrow III in FIG. 2, that is, a front view of the engine 16. FIG. 4A is a plan view of the engine exhaust device 22 alone, and FIG. 4B is a left side view of the engine exhaust device 22 alone.

As shown in FIG. 3, the engine 16 mounted on the motorcycle 1 is a parallel four-cylinder engine as described above, and has a crankshaft 25 extending in the vehicle width direction in a crankcase 18 thereof. A flywheel magneto device 26 is provided at one end of the crankshaft 25, in this embodiment, at the left end (the right end in FIG. 3) in the traveling direction of the vehicle, and is covered by a magneto cover 27 from outside. Will be On the other hand, a clutch device 28 is provided at the other end of the crankshaft 25 and is covered by a clutch cover 29 from outside.

FIGS. 2, 3, 4 (a) and 4 (b)
As shown in (1), upstream ends of four exhaust pipes 23a to 23d are connected to the front of each cylinder assembly 17. Here, these exhaust pipes 23a
To 23d for convenience, rightward in the traveling direction of the vehicle (FIG. 3
From the left) to the first pipe 23a, the second pipe 23
b, a third pipe 23c, and a fourth pipe 23d.

Each of the exhaust pipes 23a to 23d temporarily extends downward from the front surface of the engine 16 and then extends rearward around the lower portion of the engine 16. Each of the exhaust pipes 23a to 23d is arranged such that the first and second pipes 23a and 23b near the oil pan 30 provided at the lower part of the crankcase 18 of the engine 16 have the right front collecting pipe 31R.
In addition, the third and fourth pipes 23c and 23d are once gathered into two pieces by the left front collecting pipe 31L, and these front collecting pipes 31R and 31L are further combined by one rear collecting pipe 32. After being assembled into a book, the book is divided into two parts, left and right, and connected to the left and right mufflers 24, respectively.
And the other exhaust device 22 except the left and right mufflers 24,
That is, the respective exhaust pipes 23a to 23d, the left and right front collecting pipes 31R and 31L, and the rear collecting pipe 32 are accommodated in the cowling 15 described above.

Incidentally, the motorcycle 1 according to the present invention includes an exhaust gas purifying device (not shown in detail). This purifying device detects, for example, the oxygen concentration in the exhaust gas, and changes the air-fuel ratio in accordance with the detected value, so that carbon monoxide (CO), hydrocarbon (HC), nitrogen oxide ( It reduces the generation of harmful components such as NOx). If a catalyst is provided in the exhaust system, the exhaust gas purification efficiency can be further improved.

In the present invention, an exhaust gas sensor 33 such as an O ₂ (oxygen) sensor or an A / F (air-fuel ratio) sensor is used as means for detecting the oxygen concentration in the exhaust gas. The exhaust gas sensor 33 includes left and right front collecting pipes 31R, 31R.
L, one of the front collecting pipes, preferably the front collecting pipe opposite to the clutch device 28 across the center of the vehicle body 1, as shown in FIGS. 4 (a) and 4 (b) in this embodiment. , Attached to the left front collecting pipe 31L.

FIG. 5 is an enlarged view of the portion where the exhaust gas sensor 33 shown in FIG. 4A is attached, and FIG.
It is sectional drawing which follows the I line. As shown in FIG. 5, the exhaust gas sensor 33 is arranged at a position which does not interfere with the plane shape of the oil pan 30 in plan view, and is arranged behind the magneto cover 27 in side view as shown in FIG. Further, as shown in FIG. 3 and FIG.
Are arranged substantially parallel to an extension line 34 of the bank angle formed by the vehicle body 1 at the time of banking.

Next, the operation of the present embodiment will be described.

The four exhaust pipes 23a to 23d extending from the front of the engine 16 are connected to the front collecting pipes 31R, 31R.
The engine exhaust device 22 of the motorcycle 1 in which the front collecting pipes 31 </ b> R and 31 </ b> L are collectively collected together by the rear collecting pipe 32,
By attaching the exhaust gas sensor 33 to one of the left and right front collecting pipes 31R and 31L in the present embodiment, the left front collecting pipe 31L, a plurality of exhaust gas sensors 33 are arranged on each exhaust pipe. The number of parts can be greatly reduced as compared with the conventional one, and the cost can be reduced.

The left front collecting pipe 31L to which the exhaust gas sensor 33 is attached is arranged on the opposite side of the center of the vehicle body 1 from the clutch device 28. By arranging the pan 30 at a position that does not interfere with the plane shape of the pan 30, the engine 16
The lower space can be effectively used, and the capacity of the oil pan 30 can be sufficiently ensured.

The exhaust gas sensor 33 is disposed behind the magneto cover 27 in a side view, and the exhaust gas sensor 33 is connected to an extension 3 of the bank angle formed by the vehicle body 1 when banking.
4 is arranged almost parallel to the motorcycle 1
The possibility that the exhaust gas sensor 33 is damaged is reduced even when the vehicle falls down. In particular, since the left front collecting pipe 31L to which the exhaust gas sensor 33 is attached is disposed in the cowling 15 covering the front part of the vehicle body 1, the exhaust gas sensor 33 is used not only when the motorcycle 1 falls but also when the motorcycle 1 falls down. It is well protected in running conditions.

[0031]

As described above, according to the exhaust gas sensor mounting structure for a motorcycle according to the present invention, four exhaust pipes extending from the front of the engine are once divided into two by two front collecting pipes. In a motorcycle equipped with an engine exhaust device in which these front collecting pipes are collected into one by a single rear collecting pipe, the front left and right front collecting pipes are combined into one of the left and right front collecting pipes. Since the exhaust gas sensor is attached, the number of parts and the cost can be reduced.

The engine includes a crankshaft extending in the vehicle width direction of the vehicle body, a flywheel magneto device provided at one end, a clutch device provided at the other end, and a front collecting pipe for mounting the exhaust gas sensor. Is disposed on the opposite side of the clutch device with respect to the center of the vehicle body, and the exhaust gas sensor is disposed at a position not interfering with the plane shape of the oil pan provided below the engine in plan view. Can be used effectively and the capacity of the oil pan can be sufficiently secured.

Further, the exhaust gas sensor is disposed behind a magnet cover that covers the flywheel magneto device in side view, and the exhaust gas sensor is disposed substantially parallel to an extension of a bank angle formed when the vehicle body is banked. In addition, it is possible to prevent the exhaust gas sensor from being damaged when falling down.

[Brief description of the drawings]

FIG. 1 is a left side view of a motorcycle showing one embodiment of a motorcycle exhaust gas sensor mounting structure according to the present invention.

FIG. 2 is a left side view of a central portion of the vehicle body with a cowling removed.

FIG. 3 is a view taken in the direction of the arrow III in FIG. 2;

FIGS. 4A and 4B are a plan view and a left side view of the engine exhaust device alone, respectively.

FIG. 5 is an enlarged view of an exhaust gas sensor mounting portion shown in FIG.

FIG. 6 is a sectional view taken along the line VI-VI in FIG. 5;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Motorcycle (body) 16 Engine 22 Engine exhaust device 23a-23d Exhaust pipe 25 Crankshaft 26 Flywheel magneto device 27 Magneto cover 28 Clutch device 30 Oil pan 31R, 31L Front collecting pipe 32 Rear collecting pipe 33 Exhaust gas sensor 34 Bank Corner extension

Claims (3)

[Claims] 1. Four exhaust pipes extending from the front of an engine are once collected by two front collecting pipes, and these front collecting pipes are combined into one by a single rear collecting pipe. In the motorcycle including the assembled engine exhaust device, the left and right front collecting pipes 31R, 3R are provided.
An exhaust gas sensor mounting structure for a motorcycle, wherein an exhaust gas sensor 33 is mounted on one of the front collecting pipes 31L in 1L. The engine 16 includes a crankshaft 25 extending in the vehicle width direction of the vehicle body 1, a flywheel magneto device 26 provided at one end, a clutch device 28 provided at the other end, and the exhaust gas sensor 33.
A front collecting pipe 31 </ b> L for attaching the oil pan 30 is disposed on the opposite side of the clutch device 28 with respect to the center of the vehicle body 1. The motorcycle exhaust gas sensor mounting structure according to claim 1, wherein the exhaust gas sensor mounting structure is arranged at a position where the exhaust gas sensor does not interfere with the vehicle. 3. The exhaust gas sensor 33 is disposed behind a magnet cover 27 that covers the flywheel magneto device 26 in a side view, and the exhaust gas sensor 33 is connected to an extension line 34 of a bank angle formed by the vehicle body 1 at the time of banking.
An exhaust gas sensor mounting structure for a motorcycle according to claim 2, wherein the exhaust gas sensor mounting structure is arranged substantially in parallel with the vehicle.