JPH02119610A - Exhaust gas device for motorcycle - Google Patents

Abstract

PURPOSE:To heighten the degree of freedom for the design of an oil pan by guiding a plural number of exhaust pipes taken out from the cylinders above a crankcase, from the fore of an engine to the downward thereof and gathering them by the side of a bulging part of an oil pan below the crankcase. CONSTITUTION:An engine 13 is mounted on a crankcase 14 in such a way that fore and aft cylinders 15 look a V-shape, when seen from the side. On the plural number of exhaust ports 26 of the fore cylinder 15, for an example, exhaust pipes 28a, 28b are connected. In this case, each exhaust pipe 28a, 28b are guided from the fore of the engine 13 to the downward thereof. Furthermore, each exhaust pipe 28a, 28b are gathered together through a manifold joint 33 under a crankshaft and beside an oil pan 29. Each exhaust pipe 28a, 28b are connected, at the back of the manifold, with the front end face of an extended part 31a of an exhaust gas chamber 30. This solves the bumping of each exhaust pipe 28a, 28b against the oil pan 29.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to an exhaust system for a motorcycle equipped with a multi-cylinder engine.

[Prior Art] In a motorcycle equipped with a multi-cylinder engine, a plurality of exhaust pipes from the cylinders are guided downward from the front of the engine, collected at the bottom of the crankcase, and then connected to a muffler pipe at the rear. There is.

[Problems to be Solved by the Invention] Incidentally, in the known multi-cylinder engine, since the collecting part of the exhaust pipes passes under the oil pan at the bottom of the crankcase, the distance between the collecting part of the exhaust pipes and the road surface is narrow. There is a risk that this may hinder the operation of motorcycles. Therefore, in order to eliminate this problem, it is necessary to install the engine higher or to reduce the depth of the oil pan. However, there are problems in that if the engine is installed higher, the stability of the two-wheeled motor vehicle deteriorates, and if the depth of the oil pan is reduced, the oil pan itself cannot perform its functions satisfactorily. Additionally, because the exhaust pipe assembly passes under the oil pan at the bottom of the crankcase, the front and bottom of the oil pan are blocked by the exhaust pipe, reducing the cooling efficiency of the oil pan while driving. Yes.

This invention was made in view of the problems of the prior art, and its purpose is to install the engine at a low position, ensure a sufficient depth of the oil pan, and The present invention aims to provide an exhaust system for a motorcycle that does not impair cooling efficiency.

[Means for Solving the Problem] In order to achieve the above object, the exhaust system for a motorcycle according to the present invention guides a plurality of exhaust pipes from the cylinder on the crankcase downward from the front of the engine, and The plurality of exhaust pipes are assembled at the side of the oil pan bulge in the lower part of the crankcase.

[Effects] A plurality of exhaust pipes are guided downward from the front of the engine, and the plurality of exhaust pipes are gathered at the side of the oil pan bulge at the bottom of the crankcase, so the oil pan can be installed as desired regardless of the exhaust pipes. Since there is no exhaust pipe at the front or bottom of the oil pan, the cooling efficiency of the oil pan during driving is not impaired.

[Example] Embodiments of the invention will be described below with reference to the drawings.

Figure 1 shows a two-wheeled motor vehicle, where 1 is a frame, 2 is a front fork, 3 is a steering wheel, 4 is a fuel tank, and 5 is a sort. The frame 1 is mainly composed of a head vibro, a pair of left and right down tubes 7.7, a main pipe 8.8, and backstays 9, 9 (only one of which is shown), and has a double cradle shape as a whole. is doing. Brackets 10.10 (only one is shown) are attached to the lower ends of the main vibrators 8, 8, and between these brackets 10.10, the front end of the rear arm 12, which pivotally supports the drive shaft 11, is attached. It is pivotally supported. Further, a water-cooled four-stroke four-cylinder engine 13 is suspended and supported on the frame l. This engine 13 has a crank case 14
A front cylinder 15 and a rear cylinder 16 are erected on the top with a predetermined included angle in the longitudinal direction of the vehicle body, and the front cylinder 15 and rear cylinder 16 are arranged in a ■ shape when viewed from the side. has been done. The front cylinder 15 and the rear cylinder 16 are comprised of cylinder blocks 18a and 19a each having a pair of left and right cylinders inside, and the cylinder block 1.
Cylinder head portions xsb and x covered by 8a and 19a
9b, these cylinder head parts 18b,
A pair of intake ports 20, 20 and 21.degree. 21 (only one of which is shown) are provided on the opposing surfaces of 19b, respectively. Further, an air cleaner 22, an air flow meter 23, and an intake chamber 24 are arranged between the engine 13 and the fuel tank 4. From the bottom surface of the intake chamber 24, four intake pipes 2 are connected to the intake connection ports 20.20 and 21.21.
5... are led out, and a fuel injection valve is attached to each intake pipe 25, although not shown in detail. The fuel injection valve is configured to inject fuel into the intake pipe 25 according to the intake percentage flow rate, and for this reason, the engine 1 of this embodiment
3 employs a fuel injection method as a fuel supply means.

On the other hand, a pair of exhaust ports 26, 26 and 27, 27 are provided on the front surface of the cylinder head section 18b of the front cylinder 15 and the rear surface of the cylinder head section 19b of the rear cylinder 16, respectively. 15 is a front exhaust, and a rear cylinder 16 is a rear exhaust.

Front exhaust pipes 28a and 28b are connected to the exhaust ports 26.26 of the front cylinder 15. These front exhaust pipes 28a and 28b are led out from the exhaust ports 26 and 26, and then guided downward in front of the engine 13.
However, the exhaust pipe 28a on the right side in the direction of travel is the exhaust pipe 2B on the left side.
It is curved toward the b side and diagonally crosses the front of the crankcase 14. and front exhaust pipes 28a, 28
The lower end portions of b are vertically juxtaposed on one side of the crankcase 14 and routed to the side of an oil pan 29 that bulges out on the lower surface of the front end of the crankcase 14 . Further, the lower end portions of these front exhaust pipes 28a, 28b are led out from here toward the rear, and this lead-out end portion is located below the crankshaft 17.

On the other hand, rear exhaust pipes 32a and 32b are connected to the exhaust ports 27.27 of the rear cylinder 16.

These rear exhaust pipes 32a, 32b are led out from the exhaust ports 27.degree. 27 and then guided downward between the rear surface of the crankcase 14 and the rear arm 12. is curved toward the right rear exhaust pipe 32b and diagonally crosses the rear of the crankcase 14, so that the rear exhaust pipes 32a, 32b
The lower end portions of the crank case 14 are juxtaposed front and back on the right side of the crankcase 14. The lower end portions of the rear exhaust pipes 32a, 32b are routed forward, and the lead-out end portions are guided below the crankshaft 17.

Further, an oil pan 29 is located below the crankcase 14.
An air chamber 30 is located behind the n air chamber 30. The exhaust chamber 30 is integrally provided with extending portions 31 a and 31 b extending forward on both sides of its front end, and these extending portions 31 a and 31 b are located on both sides of the oil pan 29 . The front exhaust pipes 28a, 28b are combined into one pipe below the crankshaft 17 and on the side of the oil pan 29 via a collecting pipe joint 33, and further behind this collecting part, the exhaust pipes 28a and 28b are connected to the exhaust chamber. 30 is connected to the front end surface of one of the extending portions 31a. On the other hand, the crankshaft 17 also exists in the rear exhaust pipes 32a and 32b.
They are collected into one pipe below through a collecting pipe joint 34, and this collecting part is connected to the upper surface of the front end of the other extending part 31b of the exhaust chamber 30.

A pair of left and right muffling pipes 35, 35 (only one of which is shown) is connected to both sides of the rear end of the exhaust chamber 30. Further, in FIG. 1, reference numeral 36 indicates a radiator attached to the down tube 7.7, and 37 indicates a shock absorber for suspending the rear arm 12.

[Effects of the Invention] In the present invention, a plurality of exhaust pipes from the cylinders on the crankcase are guided downward from the front of the engine, and the plurality of exhaust pipes are assembled at the side of the oil pan bulge in the lower part of the crankcase. This prevents the collecting part of the exhaust pipe from passing under the oil pan at the bottom of the crankcase.
A sufficient distance is ensured between the collecting part of the exhaust pipe and the road surface, so that there is no risk of interfering with the operation of the two-wheeled motor vehicle. Furthermore, since there is no obstruction under the oil pan, there is no need to raise the engine installation position or reduce the depth of the oil pan, improving the stability of the motorcycle. Moreover, the oil pan itself can fully perform its functions. Roughly,
Since the front and bottom portions of the oil pan are not blocked by the exhaust pipe, the cooling efficiency of the oil pan during driving is not impaired.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, in which Fig. 1 is a side view of the motorcycle, Fig. 2 is a front view of the engine, Fig. 3 is a rear view of the engine, and Fig. 4 is a bottom view of the engine. It is. 13...Engine, 14...Crankcase, 15
...Cylinder, 28a, 28b...Exhaust pipe, 29.
... Oil pan, 33... Collection pipe joint. Figure 2 Patent applicant Yamaha Motor Co., Ltd. agent Patent attorney Art supplies Mikio 3o Doso diagram Figure

Claims (1)

[Claims] 2. An automatic vehicle characterized in that a plurality of exhaust pipes from cylinders on the crankcase are guided downward from the front of the engine, and the plurality of exhaust pipes are gathered at a side of an oil pan bulge in the lower part of the crankcase. Exhaust system for wheeled vehicles.