JPS635579B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a parallel or V-type multi-cylinder internal combustion engine having three or more cylinders, particularly an overhead camshaft that has a protrusion in the center of the engine that forms a camshaft drive mechanism housing chamber. The present invention relates to a mounting device for a carburetor in a type internal combustion engine.

Regardless of the valve type, in the case of a multi-cylinder engine, the carburetor is close to the cylinder due to the arrangement and shape of the cylinder or the relationship with the surrounding body frame structure and other parts, and the carburetor is close to the cylinder and the intake port of that cylinder and the carburetor In some cases, it may not be possible to connect the intake pipes between the devices using flange joints or union nuts.

Therefore, the intake port of the cylinder and the carburetor are connected by insertion using a short tube made of, for example, synthetic rubber and having heat insulating properties and vibration absorbing properties. This plug-in connection using an insulating tube allows for easy plug-in connection to the intake port of the cylinder by fitting one end of the insulating tube into the carburetor and fixing it in advance. It is effective when installed.

In the case of the above-mentioned plug-in connection, in order to prevent the connection from coming off due to vibration or the like, it is necessary to provide circumferential grooves on the fitting surfaces and protrusions that fit into the grooves to engage each other.

If necessary, tighten the band further.

However, in overhead camshaft (OHC) multi-cylinder engines, the cam drive chain is located in the center of the engine, so the bulge that forms the housing chamber for the chain and the inner cylinder Even if an attempt is made to cut a groove on the outer periphery of the intake port when the intake port is close to the intake port, the processing tool will interfere with the protruding portion, making it impossible to process the groove.

In that case, since it is possible to process the inner periphery, it is conceivable to form a female thread in the intake port part of the engine and screw and secure the intake port part that is separate from the engine body into this. This results in high costs due to the preparation of internal threads and the machining of internal threads.

In view of the problem of the connection between the carburetor and the cylinders in the above-mentioned overhead camshaft multi-cylinder internal combustion engine, the present invention proposes that when the carburetor and the intake port of each cylinder are inserted and connected via an insulating cylinder, the cam in the center of the engine There is no circumferential groove provided on the outer periphery of the intake port of the cylinder that is close to the protrusion that forms the shaft drive mechanism housing chamber, and the connection is simply inserted, allowing for easy vaporization without the risk of it coming off. The present invention provides a device for attaching a device.

To explain the structure of the embodiment shown in the figure, Figure 1 is a side view of a motorcycle equipped with an air-cooled OHC parallel four-cylinder internal combustion engine 1, and shows the structure between the engine 1 and the air purifier 2 behind it. A vaporizer 3 is arranged in a narrow space.

As shown in FIG. 2, one carburetor 3 is provided for each intake port 41 to 44 of each cylinder, and the four carburetors 3 are connected together by a support plate 5.

And for each vaporizer 3, an insulating tube 61 is installed at the outlet of the vaporizer 3.
- 64 is fitted, and the circumferential groove 7 formed on the carburetor side is engaged with the circumferential protrusion 8 formed on the inner periphery of the end of the cylinders 61 - 64. The insulating cylinders 61 to 64 are each fastened and fixed to the vaporizer 3 by bands 9.

The other ends of each of the insulating cylinders 61 to 64 are plugged and connected to the corresponding intake ports 41 to 44, respectively. The circumferential grooves 10 formed engage the circumferential protrusions 11 on the inner peripheries of the ends of the insulating cylinders 61 and 64, and the bands 12 are further tightened around the circumferential grooves 10. The inner air intake ports 42, 43 and the insulating tubes 62, 63, which are close to the protrusion 13 forming the chain storage chamber etc., are connected by a so-called seal fitting without grooves or protrusions. has been done.

Figure 3 shows a water-cooled OHC type V-type four-cylinder internal combustion engine 1.
This is an enlarged side view of the engine-mounted part of a motorcycle equipped with the front cylinders 1A and 1B, and the rear cylinders 1C and 1B.
In the space between 1D, a vaporizer 3 is arranged which is connected to four air purifiers integrally formed through a support plate 5 (shown in the fifth figure).

Each carburetor 3 has an insulating cylinder 6 connected to each intake port 41 to 44 of the corresponding cylinder, as in the example shown in FIG.
1 to 64 are plug-connected.

As shown in Fig. 4, both outer air intake ports 4
There is a circumferential groove 10 on the outer periphery of the intake ports 1 and 44, and there is no groove on the outer periphery of the intake ports 42 and 43, which are adjacent to the central protrusion 13, respectively. 14 is a cooling water pipe.

That is, as shown in FIG.
On the other hand, the insulating tubes 61 and 64 are prevented from coming out by the engagement between the grooves 10 and the protrusions 11, but the insulating tubes 62 and 63 are simply secured against the inner air intake ports 42 and 43. It's just that. Inner intake port 4
If necessary, the band 12 is hung around the fitting portions of the insulating tubes 62 and 63 to the insulating tubes 2 and 43.

As described above, the carburetor mounting device of the present invention is used to connect the intake port of each cylinder and the carburetor via an insulating tube in an overhead camshaft type internal combustion engine with three or more cylinders. The insulating tube is connected to the intake port of the inner cylinder by engaging the circumferential grooves and ridges formed on the mating surfaces at the same time as the insertion to prevent the insulating tube from coming out. Since the carburetor is simply inserted, it is easy to install the carburetor and there is no risk of it coming off.Moreover, there is a protrusion between the inner cylinders that forms the camshaft drive mechanism housing chamber. Even if the intake port is close to the inner side, it can be installed without any problem, and there is no need to perform any processing around the inner intake port, thereby reducing the manufacturing cost of the overhead camshaft multi-cylinder internal combustion engine.

[Brief explanation of the drawing]

Fig. 1 is a side view of a motorcycle equipped with an in-line 4-cylinder internal combustion engine, Fig. 2 is a partially cutaway plan view of an example in which the present invention is applied to an in-line 4-cylinder internal combustion engine, and Fig. 3 is a V-type 4-cylinder internal combustion engine. FIG. 4 is a side view of an internal combustion engine; FIG. 4 is a plan view of a V-type four-cylinder internal combustion engine in which the device of the present invention is implemented without a carburetor installed; FIG. 5 is a part of an example in which the device of the present invention is implemented in the engine. Cutaway side view. 1 is a multi-cylinder internal combustion engine, 3 is a carburetor, 41 to 44
61 to 64 are inlet ports, 7 and 10 are circumferential grooves, 8 and 11 are circumferential protrusions, 9 and 12 are bands, and 13 is a protrusion.

Claims (1)

[Claims] 1. In an overhead camshaft internal combustion engine with three or more cylinders in which the carburetor and the intake port of each cylinder are plugged in and connected via an insulating tube, the insulating tubes connected to the intake ports of both outer cylinders are connected at the same time as they are inserted. The insulating cylinder for the intake port of the cylinder near the protrusion that forms the camshaft drive mechanism housing chamber in the center of the engine engages the circumferential groove and protrusion formed between the fitting surfaces. , carburetor mounting device for multi-cylinder internal combustion engines with plug-only connection.