JPH0437249B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement of a secondary air supply device for a V-type engine used in a motorcycle or the like.

A V-type engine with a horizontal V-side crankshaft is used as an internal combustion engine for motorcycles.On the other hand, the engine's exhaust purification system supplies secondary air to the exhaust gas and removes HC and CO from the exhaust gas. What is done is done.

Such a secondary air supply system supplies secondary air from the air cleaner to the exhaust port of each cylinder through a conduit through a secondary air control valve, and a reed valve serving as a one-way valve is interposed in the conduit. The exhaust pulsation is used to supply secondary air into the exhaust.

By the way, such a V-type engine has cylinders at the front and rear, and each cylinder requires a reed valve for supplying secondary air, and when connecting the reed valve and the air cleaner with piping, the reed valve is placed on the side of the engine. If they are installed, the reed valve and piping will not fit within the width of the engine, which is not preferable. On the other hand, it is also possible to arrange the reed valve in the space between the front and rear cylinders, but in this case, it is necessary to arrange auxiliary equipment such as a carburetor that forms the fuel supply device between the upper parts of the front and rear cylinders. Considering,
Particularly in so-called narrow-angle V-type engines, where the valley between the front and rear cylinders is narrow, providing space between the cylinders is a space issue.
The arrangement of auxiliary equipment, their installation and removal, and the piping arrangement when installing reed valves are unfavorable.

The present invention has been made in view of the need for V-type engines, particularly narrow-angle V-type engines in which the valley between the front and rear cylinders is narrow.

The object of the present invention is to provide a one-way valve for supplying secondary air by effectively utilizing dead space within the width of the engine in a V-type engine, and to provide a one-way valve directly below the exhaust port. To provide a secondary air supply device for a V-type engine in which the secondary air supply passage is simplified.

To achieve the above object, the present invention provides a V-type engine installed in a vehicle, in which a one-way valve is installed in a dead space formed in front of a cylinder block, behind a cylinder block, and below a cylinder head, close to an exhaust port. Let me install it...
We aim to make effective use of dead space, shorten and simplify the secondary air supply passage that connects to the one-way valve, and further improve the appearance by making the one-way valve difficult to see from the outside with the exhaust pipe that connects to the exhaust port. Furthermore, the air intake system is arranged between so-called banks, and the equipment is disposed in a distributed manner to reduce the size. It is characterized by the following.

Next, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a schematic side view of the motorcycle 1. To explain the outline, a front fork 4 that supports a front wheel 5 is supported in a steerable manner via a head tube 3 at the front end of the frame 2, and a front upper part of the frame 2 is supported. A fuel tank 6 is attached to the fuel tank 6, and a seat 7 is attached to the rear thereof. A rear fork 8 supporting a rear wheel 9 is pivotally extended from the rear of the lower front part of the frame 2, and a rear action unit 10 is interposed between the rear fork 8 and the frame.

In the embodiment, the frame 2 includes a main frame 2a extending rearward from the head tube 3, a down tube 2b extending downward, a down tube blower 2c extending rearward from the lower end of the main frame 2a, and a down tube blower 2c slightly extending from the rear of the main frame 2a. A center pipe 2d that is erected so as to tilt forward and is connected to the rear end of the main frame 2a.
, an upper pipe 2e extending rearward from the upper part and forming a seat rail, and a subtube 2f tilted rearward and upward so as to connect the rear end of the down tube blower 2c and the middle part of the upper pipe 2e.

An engine 11 is mounted below the fuel tank 6 of the frame 2 described above in a space surrounded by the members 2a, 2b, 2c, and 2d. Engine 11 is a water-cooled V-type engine with a side V-type and horizontal crankshaft.
In the embodiment, a two-cylinder engine with one cylinder each in the front and rear is shown.

The engine 11 has a crankcase 12 that also serves as a transmission case, a front cylinder 13 that is slightly tilted forward on the front part of the crankcase 12, and a rear cylinder 14 that is slightly tilted backwards on the middle part of the crankcase 12. The front and rear cylinders 13 and 14 are connected to cylinder block 1 from below.
31, 141, cylinder head 132 on this,
142, cylinder head cover 133 on this,
It consists of 143. In this embodiment, since the engine is a water-cooled engine, a radiator 15 is provided between the down tubes 2b in front of the front cylinders 13. A V-shaped trough S is formed between the front and rear cylinders 13 and 14 with the top and both sides open, and the angle of the trough S is narrow.
It has a so-called narrow-angle V shape, and in the example, the angle between the front and rear cylinders is 45 degrees.

An air cleaner 16 is disposed in a side triangular space surrounded by the center tube 2d, the top pipe 2e, and the subtube 2f. A blow-by gas storage tank 164 is provided below the bottom of the case 161 and communicates with the clean side inside the case.

On the other hand, a collection chamber 17 is arranged below the middle of the fuel tank 6, and this is connected to the front upper part of the air cleaner case 161 via a rear communication part 171 to supply clean side air to the chamber 17. . A carburetor 18 serving as a fuel supply device is disposed at the lower front portion of the chamber 17, and the front cylinder of the cylinder heads 132, 142 of the front and rear cylinders faces toward the rear, and the rear cylinder faces toward the front on the downstream side of the carburetor. It is connected to the intake ports 134 and 144 which are opened as shown in FIG.

Exhaust ports 135, 145 are provided in the cylinder heads 132, 142 of the front and rear cylinders, and the exhaust port 135 of the front cylinder 13 is provided with the cylinder heads 132, 142 of the front and rear cylinders.
1 opens upward in front and is connected to the exhaust pipe 19,
The exhaust pipe 19 extends downwardly to the right in front of the cylinder block 131 as shown in the fourth figure, and extends rearward through the lower right side of the engine, and is connected to the muffler 20. The exhaust port 145 of the rear cylinder 14 opens upward behind the cylinder block 141 and is connected to the exhaust pipe 21. The exhaust pipe 21 is bent to the left, passes on the left side of the cylinder blocks 141 and 131, and is connected to the front of the case 12. It is curved at , extends rearward through the lower left side of the case, and is connected to the muffler 22 .

In the above, the front and rear cylinder blocks 13
1 and 141, the front cylinders are slightly inclined forward and the rear cylinders are slightly inclined backwards, so that there is a horizontal V-shaped space A between the front part of the crankcase 12 and the front surface of the front cylinder block 131. Further, a horizontal V-shaped space B is formed between the middle upper part of the crankcase and the rear surface of the rear cylinder block 141.
A reed valve 23 for supplying secondary air is provided on the front surface of the front cylinder block 131, and the reed valve 23 connects the body 231 to a boss portion 136 provided on the front surface of the cylinder block 131.
1 is provided with a vertical passage 138 that communicates with a space 137 of the boss portion 136, and the passage 138 communicates with a passage 139 that opens to an exhaust port 135 provided in the cylinder head 132, and the body is opened and closed by a valve body 232. A space 233 within 231 is connected by a base 234 to one end of a hose 24 forming secondary air supply piping. The reed valve 23 described above is provided in the space A, and is provided directly below the exhaust port 135, so the passages 138 and 139 are short and only need to be provided vertically, so it is simple and the passages can be easily shaped. .

A similar reed valve 25 is provided on the rear surface of the rear cylinder block 141, and the reed valve 25 is connected to the body 251.
is attached to the boss portion 146 on the rear surface of the cylinder block 141.
6, the passage 148 communicates with a passage 149 that opens to an exhaust port 145 provided in the cylinder head 142, and a space 253 in the body 251 that is opened and closed by a valve body 252. is connected by a base 254 to one end of a hose 26 forming secondary air supply piping. The above reed valve 25 is provided in the space B, and the exhaust port 1
45, and therefore, as before, passages 148, 149 are short, simple, and easy to mold.

A secondary air control valve 28 is installed directly in the main body of the air cleaner case 161 between the front of the middle lower part of the air cleaner case 161 and the rear surface of the cylinder block 141 of the rear cylinder. The control valve 28 is connected to the clean side inside the case 161 through a pipe body 282 through a base 281, and the pipe body 282 has its upstream end facing near the rear wall of the case and above the bottom to prevent blow-by gas from flowing in. That's what I did. A valve body 285 faces between the orthogonal passages 283 and 284 in the valve 28, and includes a negative pressure chamber 287 that introduces the negative pressure downstream of the throttle valve of the carburetor 18 through a conduit 286. The diaphragm 289 is sucked during high negative pressure such as during deceleration, and the valve body 285 closes the passages 283 and 2.
84 and the secondary air exhaust port 135,1
Cut off the supply to 45. Passage 2 extending upward
84 is connected to one end of the hose 29, while an inverted Y-shaped joint fitting 30 is provided above,
Connect the first fitting part 301 facing downward to the hose 2.
At the other end of the hose 26, a second cap part 302 facing downward is connected to the other end of the hose 26, and the first cap part 301 is connected to the other end of the hose 26.
A third mouthpiece 303 facing upward in the forward direction is connected to the other end of the hose 26, and the first mouthpiece 30
1 and a third mouthpiece 303 facing upward in the forward direction is connected to the other end of the hose 24. As a result, the path to the distant hose 24 and therefore the reed valve 23 of the front cylinder will be in the forward direction, while the path to the near reed valve 25 of the rear cylinder will cross the path 284 in the opposite direction, so that both far and near This makes it possible to send secondary air almost evenly to the reed valve. The bolt 27 shown in FIG. 5 that fixes the body 231 also serves to prevent the reed valve body 232 from coming off.

As is clear from the above, according to the present invention, in a V-type engine, one-way valves are installed near the exhaust ports at the front and rear of the front and rear cylinder blocks below the inclined cylinder head, and the intake system is arranged between the so-called banks. Therefore, the dead space peculiar to a V-type engine, which is defined at the front and rear of the cylinder block under the cylinder head that extends front and rear, can be effectively used as the space for arranging the one-way valve, and the one-way valve and the exhaust port can be placed close together. This shortens and simplifies piping, eliminates restrictions on the installation location of auxiliary equipment, and also provides a good appearance by making the one-way valve difficult to see from the outside with the exhaust pipe that connects to the exhaust port. Furthermore, the intake system can be placed away from the one-way valve, and the equipment can be distributed to reduce the size.

Although a two-cylinder engine is shown in the embodiment, the present invention can also be applied to a three-cylinder engine with one front cylinder and two rear cylinders, a four-cylinder engine with two cylinders each in the front and rear, or even an engine with a larger number of cylinders.

[Brief explanation of drawings]

Figure 1 is a side view of the motorcycle, Figure 2 is a partially cutaway side view of the main parts including the engine, Figure 3 is an enlarged view of the same, and Figure 4 is an explanatory plan view of the engine. 5 is a front view of the front cylinder block. In the drawing, 11 is the engine, 13 and 14 are the front and rear cylinders, 131 and 141 are the cylinder blocks, and 2
3 and 25 are one-way valves.

Claims (1)

[Claims] 1. A crankshaft supported by a crankcase is mounted on a vehicle and extends in the vehicle width direction, and cylinders extend forward and rearward from the crankcase, and cylinders are provided at the front and rear of the crankshaft. In a V-type engine for a vehicle, the intake system for each cylinder is arranged in the valley part of the V-type engine, and exhaust ports are formed on the front surface of the front cylinder and the rear surface of the rear cylinder, respectively.
Exhaust pipes are connected to these exhaust ports in a downward direction, and one-way valves for supplying secondary air are arranged below the cylinder head and on the front surface of the front cylinder and the rear surface of the rear cylinder. V-type engine secondary air supply system.