JPH0583354U - Engine intake system - Google Patents

Abstract

(57) [Abstract] [Purpose] In an intake device having a carburetor with a horizontal intake passage and an air horn connected to the upstream side of the carburetor, the liquid horn is prevented from flowing out of the air horn due to the engine backflow phenomenon, and the air horn is prevented. It enables the flattening of the intake silencer box that houses the. [Structure] The air horns 33 ₁ and 33 ₂ are bent so that their inlets face upward.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an engine intake device, and in particular, an intake silencer box is connected to a carburetor having a horizontal intake passage connected to an intake port of a cylinder head, and an air horn connected to the upstream end of the intake passage is connected to the inside of the intake silencer box. The ones rushed in to "improve".

[0002]

[Prior Art]

 Such an intake device is already known, as disclosed in, for example, Japanese Utility Model Publication No. 47-27080.

[0003]

[Problems to be solved by the device]

 The air horn in such an intake system compensates for the shortage of the intake pipe length of the engine and enhances the filling efficiency due to the inertial effect of the intake air, but when this is arranged horizontally like the intake passage of the carburetor, When the engine blows back, liquid fuel adhering to the inner wall of the intake passage may be pushed out of the air horn. In addition, the air horns that are simply placed on the horizontal plane become an obstacle when making the intake silencer box compact.

The present invention has been made in view of the above circumstances, and it is possible to prevent the liquid fuel from flowing out of the air horn due to a blowback phenomenon and to make the intake silencer box flat. The purpose is to provide.

[0005]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention is characterized in that an air horn is bent so that its inlet faces upward.

[0006]

【Example】

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

First, in FIG. 1, an outboard motor 2 attached to the tail of the hull 1 includes a casing 3 that supports a screw 4 at a lower end portion thereof, and an engine 5 mounted on an upper surface of the casing 3. An engine cover 6 that covers the engine 5 is detachably fixed to the casing 3. The engine 5 is configured in a vertical manner with its crankshaft 7 oriented vertically, and the crankshaft 7 is connected to a drive device 8 in the casing 3 to drive the screw 4.

Hereinafter, in the outboard motor 2, the terms “front” and “rear” are referred to as being attached to the hull 1. Thus, an air intake 9 that opens rearward is provided at the top of the engine cover 6.

2 and 3, the engine 5 includes a pair of left and right banks 12 that project obliquely rearward from a crank case 10 that supports a crank shaft 7 so as to form a V shape with each other.₁ , 12₂It is configured as a V type with both banks 12₁, 12₂Each has two cylinders 13₁, 13₂Have. And both banks 12₁, 12₂The cylinder 13₁, 13₂Piston 14 sliding inside₁, 14₂Is connecting rod 15₁, 15₂It is connected to the common crankshaft 7 via. At that time, left bank 12 ₁ Connecting rod 15₁Is the corresponding right bank 12₂Connecting rod 15₂ Is located below the left bank 12 because of such an arrangement.₁Right bank 1 2₂On the other hand, a fixed distance a (see FIG. 4) is offset downward along the axial direction of the crankshaft 7.

Both banks 12₁, 12₂Cylinder head 16₁, 16₂Is a pair of upper and lower intake ports 17 whose downstream side is bifurcated.₁, 17₂Similarly, a pair of upper and lower exhaust ports 18₁, 18₂Is a pair of upper and lower cylinders 13₁, 13₂Corresponding to each intake port 17₁, 17₂A pair of intake valves 19 that open and close the bifurcated part for each ₁ , 19₂However, each exhaust port 18₁, 18₂Exhaust valve 20 that opens and closes it each time ₁ , 20₂Is provided.

[0011] V-shaped space 21 between both the banks 12 _1, 12 ₂ includes an intake manifold 23 having an intake passage 22 _1, 22 ₂ continuous respectively to the intake ports 17 _1, 1 7 _2, the intake passage 22 ₁ a carburetor 25 _1, 25 ₂ are disposed with a horizontal intake path 24 _1, 24 ₂ continuous respectively 22 _2. The intake manifold 23 is bolted to bridge both cylinder heads 16 ₁ and 16 ₂ . The left and right carburetors 25 ₁ and 25 ₂ are located at the same height above the downstream ends of the corresponding intake ports 17 ₁ and 17 ₂ , and the center O between the two carburetors 25 ₁ and 25 ₂ is located in both banks. A constant distance b (see FIG. 4) is offset from the center plane Y between the 12 ₁ and 12 ₂ to the left bank 12 ₁ side located below.

In FIGS. 2 and 5, the intake passages 24 ₁ and 24 ₂ of the carburetors 25 ₁ and 25 ₂ have choke valves 26 ₁ and 26 _{2 on} the upstream side and throttle valves 27 ₁ and 27 ₂ on the downstream side. Is provided. Both choke valves 26 ₁ and 26 ₂ are supported by a choke shaft 28 which is connected to each other via a joint on an axis orthogonal to the center plane Y, and the throttle valves 27 ₁ and 27 ₂ are also connected to the center plane Y. The throttle shafts 29 are connected to each other via joints on orthogonal axes. A common choke actuating mechanism 30 is connected to the upper and lower choke shafts 28, 28, and a common throttle actuating mechanism 31 is connected to the upper and lower throttle shafts 29, 29. The choke valves 26 ₁ , 26 ₂ and the throttle valves 27 ₁ and 27 ₂ are opened and closed. These actuating mechanisms 30 and 31 are arranged on the outer side of the right carburetor 25 ₂ on the side opposite to the offset direction of the center b between the left and right carburetors 25 ₁ and 25 ₂ .

[0013] All carburetor 25 _1, 25 ₂ of the upstream end is connected to a common intake silencer box 32, four air horn 33 ₁ extending from the total intake airway 24 _1, 24 ₂ of the upstream end, 33 ₂ It is placed in the air intake silencer box 32. These air horns 33 ₁ and 33 ₂ are bent so that their inlets are directed upward, and this makes it possible to flatten the intake silencing box 32 in the front-rear direction.

The intake silencer box 32 is composed of a box body 32a fixed to the full vaporizers 25 ₁ and 25 ₂ and a cover body 32b separably joined to the box body 32a. a pair of air da transfected ₃₄₁ for introducing air from inside the intake silencer box 32 of the cover 6, 34 ₂ are connected, these air ducts 34 _1, 34 ₂ is bent to direct the inlet to the lower side ..

Further, the engine cover 6 is provided with a cylindrical barrier 35 located immediately after the air intake 9 to prevent splashing of seawater or the like that has entered the air intake 9. The tubular barrier 35 has a notch 36 at the upper end of its side portion, and the air intake 9 communicates with the inside of the engine cover 6 through the tubular barrier 35.

Next, the operation of this embodiment will be described.

When the engine 5 is operated, the air that has flowed into the engine cover 6 from the air intake 9 through the tubular barrier 35 is drawn into the intake silencer box 32 from the air ducts 34 ₁ and 34 ₂ , and this Is divided into four air horns 33 ₁ and 33 ₂ to form a mixture in the intake passages 24 ₁ and 24 ₂ of the carburetors 25 ₁ and 25 ₂ , respectively, and the intake passages 22 ₁ and 22 ₂ and the suction ports 17 ₁ and 17 2 are formed. _It is sucked into the corresponding cylinders 13 ₁ and 13 ₂ through ₂ in sequence.

Since the air ducts 34 ₁ and 34 ₂ are bent with their inlets directed downward, the intake noise leaking into the air ducts 34 ₁ and 34 ₂ is effectively attenuated in the engine cover 6. Can contribute to noise reduction.

Further, since the vaporizers 25 ₁ and 25 ₂ occupy positions higher than the downstream ends of the corresponding intake ports 17 ₁ and 17 ₂ , liquid fuel adheres to the inner walls of the intake ports 17 ₁ and 17 _2, etc. However, this can prevent the backflow to the carburetors 25 ₁ and 25 ₂ when the engine 5 is stopped.

Further, since the air horns 33 ₁ and 33 ₂ are bent so that the inlet faces upward, when the engine 5 causes a backflow phenomenon, liquid fuel adhered to the inner walls of the intake passages 24 ₁ and 24 _2, etc. It is possible to prevent the air horns 33 ₁ and 33 ₂ from being pushed back to the outside. However, if the air horns 33 ₁ and 33 ₂ are bent as described above, it is possible to give the air horns 33 ₁ and 33 ₂ a predetermined effective length even in the flat intake silencer box 32. Further, by flattening the intake silencer 32 in the front-rear direction, the rearward protruding amount of the engine cover 6 can be suppressed to a small amount, and therefore, when the outboard motor 2 is tilted up, interference between the engine cover 6 and the hull 1 can be avoided. it can.

By the way, the intake pipe lengths of both the left and right cylinders 13 ₁ and 13 ₂ are corresponding to the intake ports 17 ₁ and 17 ₂ , the intake passages 22 ₁ and 22 ₂ , the intake passages 24 ₁ and 24 ₂ and the air horns 33 ₁ and 33 _2. Is determined by the total length of the left and right banks 12 ₁ and 12 _{2 with} respect to the center plane Y between the left and right carburetors 25 ₁ and 25 ₂ by the offset arrangement as described above. The intake pipe lengths of the cylinders 13 ₁ and 13 ₂ can be set to be substantially equal to each other, whereby the intake inertia effect can be effectively used to increase the filling efficiency of both the left and right cylinders 13 ₁ and 13 ₂ equally and to improve the output performance. Can bring improvement.

[0022]

[Effect of the device]

 As described above, according to the present invention, since the air horn is bent so that the inlet thereof is directed upward, the liquid fuel adhering to the inner wall of the intake passage or the like is not discharged to the outside of the air horn due to the engine backflow phenomenon. The outflow can be prevented by the upward inlet of the air horn, and the air horn can be bent to secure a predetermined length of the intake pipe, and the intake silencer box can be flattened.

[Brief description of drawings]

FIG. 1 is a side view of an outboard motor equipped with the engine of the present invention.

FIG. 2 is an enlarged vertical sectional view of a main part of FIG.

3 is a sectional view taken along line 3-3 of FIG.

4 is a sectional view taken along line 4-4 of FIG.

5 is a sectional view taken along line 5-5 of FIG.

[Explanation of symbols]

5 Engine 16 ₁ , 16 ₂ Cylinder head 17 ₁ , 17 ₂ Intake port 24 ₁ , 24 ₂ Intake passage 25 ₁ , 25 ₂ Vaporizer 32 Intake silencer 33 ₁ , 33 ₂ Air horn

Claims (1)

[Scope of utility model registration request] 1. A cylinder head (16 _1, 16 ₂₎ of the intake port (17 _1, 17 ₂₎ horizontal intake path communicating with (24 _1, 24 ₂₎ a vaporizer with (25 _1, 25 ₂₎
An intake silencer box (32) is connected to the intake passage (24 ₁ ,
Air horns (33 ₁ , 3) connected to the upstream end of 24 ₂ ).
In an intake system for an engine, in which 3 ₂ ) is inserted into an intake silencer box (32), the air horns (33 ₁ , 33 ₂ ) are bent so that their inlets are directed upwards. Intake device.