JPH062627A - Intake system of internal combustion engine - Google Patents

Abstract

PURPOSE:To improve the extent of intake efficiency as checking the overall height of an engine, in an intake system of a V-type internal combustion engine. CONSTITUTION:Two branch pipes 13, 14 being interconnected to each cylinder of symmetrical banks are set up so as to make them be crossed with each other in parallel, and each sectional form of upstream parts 13A, 14A and downstream parts 13C, 14C of these branch pipes 13 and 14 is formed into an oval with a long diameter in the cylinder bank direction, and each sectional form of two crossed parts 13B, 14B is formed into an oval with a short diameter in the cylinder bank direction, respectively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of an intake system for an internal combustion engine.

[0002]

2. Description of the Related Art As conditions for an intake passage provided in an automobile engine, intake efficiency is good over a wide range of rotation speeds from low speed to high speed, and in a multi-cylinder engine, distribution of air-fuel mixture to each cylinder is uniform. Is required.

An example of an intake device provided in a conventional V-type opposed 6-cylinder engine is shown in FIG. 12 (see Japanese Patent Laid-Open No. 60-69255).

Explaining this, the left and right banks 7
Two collecting parts (surge tanks) 75, 76 for collecting the branch pipes 73, 74 communicating with the respective cylinders 1, 72 for each bank
And each of the gathering portions 75 and 76 are attached to rocker covers 78 and
9 and are arranged in the cylinder row direction, and
Throttle valves 77 are provided at the ends of 6 respectively.

[0005]

However, in such a conventional device, the branch pipes 73, 74 are formed so as to be curved from between the left and right rocker covers 78, 79 to the respective upper portions. Since the overall height of the engine is determined by the diameter of each branch pipe, increasing the passage cross-sectional area of each branch pipe increases the engine hood line of the vehicle and secures a sufficient passage cross-sectional area. There was a problem that it was difficult to do.

In view of the above problems, the present invention has an object to increase the intake efficiency while suppressing the overall height of the engine in an intake system for a V-type internal combustion engine.

[0007]

According to the present invention, in an intake system provided in a multi-cylinder internal combustion engine having left and right banks facing each other in a V-shape, branch pipes communicating with intake ports of the cylinders of the left and right banks are arranged in parallel with each other. Is installed so as to intersect with each other, and two collecting portions for collecting the branch pipes connected to the cylinders whose ignition order is not continuous are provided with each other, and connected to the upstream portion connected to the collecting portion of each branch pipe and the intake port The cross-sectional shape of the downstream portion is formed in an oval shape having a major axis in the cylinder row direction, and the cross-sectional shape of an intersection connecting the upstream portion and the downstream portion is formed in an oval shape having a minor axis in the cylinder row direction.

Further, a communication pipe that communicates each collecting portion is provided above each branch pipe, and a control valve that opens and closes each communication pipe according to engine operating conditions is provided.

[0009]

[Function] Since the cross-sectional shape of the upstream and downstream portions of each branch pipe is formed into an elliptical shape having a long diameter in the cylinder row direction, the overall height of the engine is suppressed and a sufficiently large passage cross-sectional area of each branch pipe is secured. It becomes possible to do.

Since the cross-sectional shape of the intersection of the branch pipes is formed to be an ellipse having a short diameter in the cylinder row direction, the passage cross-sectional area of the intersection is limited by the distance between the branch pipes arranged so as to intersect each other. It is possible to avoid the above and secure a sufficient passage cross-sectional area.

Further, by suppressing the height of each branch pipe as described above, it becomes possible to provide a communication pipe located above the branch pipe and communicating each collecting portion.

By opening and closing the communication pipes that connect the respective collecting portions in accordance with the engine operating conditions, the resonance supercharging effect is enhanced in the low rotation speed region and the inertia supercharging effect is enhanced in the high rotation speed region so that the wide rotation speed region is increased. Inhalation efficiency can be maintained over

[0013]

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

As shown in FIGS. 1 and 2, the V-type 6-cylinder engine has a left and right cylinder heads 2 on top of a cylinder block 1.
3, the intake manifold 6 is connected to the inside of the left and right cylinder heads 2 and 3, and an exhaust pipe (not shown) is connected to the outside. It should be noted that cylinders whose ignition order is not continuous are collected in the left and right banks.

The intake manifold 6 is divided into a lower manifold 11 connected to the left and right cylinder heads 2 and 3, and an upper manifold 12 connected to the upper part of the lower manifold 11. The upper manifold 12 extends in the horizontal direction on the left and right rocker covers 4 and 5, and the branch pipes 13 and 1 communicating with the intake ports 9 of the left and right cylinder heads 2 and 3 via the lower manifold 11.
4 and two collecting units 1 for collecting the branch pipes 13 and 14
5 and 16 and two introducing pipes 17 and 18 for guiding intake air from each throttle valve 10 to each collecting portion 15 and 16, and these are integrally formed.

In the plan view (FIG. 3), each branch pipe 1
The center lines O ₄ and O _{3 of the} ones arranged at the center among the _{three and four}
Extends linearly in the direction orthogonal to the cylinder row (crankshaft), while the center lines O ₁ , O ₂ , O ₅ , O ₆ of the branch pipes 13 and 14 arranged at the front and rear ends are in the middle. It bends and intersects with the points C ₁ and C ₂ on the center lines O ₃ and O ₄ , respectively.
That is, the center lines O ₂ , O ₄ and O ₆ intersect at a point C ₁ and the center lines O ₁ , O ₃ and O ₅ intersect at a point C ₂ .

The collecting portions 15 and 16 are respectively connected to the branch pipes 13 and 14.
While extending in the cylinder row direction as a surge tank defined between the introduction pipes 17 and 18, the introduction pipes 17 and 18 are orthogonal to each other and extend in the direction orthogonal to the cylinder row from the central portions of the collecting portions 15 and 16. Part 17a, 18a and each orthogonal part 17a, 18
a parallel portion 17b which is bent from a and extends in the cylinder row direction,
18b and.

The upper manifold 12 extends horizontally on the left and right rocker covers 4 and 5, and in the front view (FIGS. 1 and 2), each of the gathering portions 16 and 15 has a left and right bank center line (cylinder center). Lines) A ₂ and A ₃ are arranged inside, and the parallel portions 18b and 17b of the introduction pipes 18 and 17 are arranged outside the bank center lines A ₂ and A ₃ .

As shown in FIG. 4, each rocker cover 4,
5, an ignition coil 41 is attached to each cylinder,
An ignition plug (not shown) is housed below each ignition coil 41. In the front view, the ignition plugs and the ignition coils 41 are arranged on the left and right bank center lines A ₂ and A ₃ , respectively, and are located outside the collecting portions 16 and 15, and the ignition coils 41 and the ignition plugs are arranged. It is easy to attach and detach.

As shown in FIG. 5, joining flanges 17c and 18c for the throttle chamber 30 are formed at the ends of the respective introducing pipes 17 and 18. This joint flange 17
The c and 18c are formed so as to be inclined downward by a predetermined angle to keep the mounting height of the throttle chamber 30 low. In FIG. 5, 47 is an exhaust pipe and 48 is a radiator fan.

The left and right throttle valves 10 are connected to the shafts 41 and 42, respectively, as shown in FIG.
Are coaxially arranged, and are linked to an accelerator pedal (not shown) via a wire in synchronization with each other.

Ducts 43 and 44 made of an elastic material are connected to the throttle chambers 30, respectively, and intake air taken in from an air cleaner (not shown) is fed to the ducts 43 and 44.
It is led through 44. In addition, the intake passage length connecting the air cleaner and the intake valve 8 of each cylinder is formed uniformly.

As shown in FIG. 7, the cross-sectional shape of the upstream portion 14A connected to the collecting portion 16 of each branch pipe 14 is formed in an oval shape having a major axis in the cylinder row direction.

As shown in FIG. 9, the sectional shape of the downstream portion 14C of each branch pipe 14 connected to each intake port 9 of the right bank is formed into an elliptical shape having a major axis in the cylinder column direction. A recess 14D facing the fuel injection valve (not shown) is formed in the upper portion of the downstream portion 14C.

As shown in FIG. 8, the cross-sectional shape of an intersection 14B connecting the upstream portion 14A and the downstream portion 14C of each branch pipe 14 is formed in an oval shape having a short diameter in the cylinder row direction.

Similarly, each branch pipe 13 connected to the left bank also has an upstream portion 13A and an intersection portion 13 each having an oval cross section.
B has a downstream portion 13C and is formed by changing the flattening direction midway.

The intake manifold 6 includes left and right collecting portions 15, 1.
A communication pipe 21 that communicates 6 is provided above each of the branch pipes 13 and 14. The communication pipe 20 has bolt holes 37 formed at the front and rear ends of the joint flanges 35 and 36, and is fastened by screwing a bolt (not shown) inserted into each bolt hole 37 into the upper manifold 12. A seal material (not shown) is interposed between the communication pipe 20 and the upper manifold 12, and a gasket, an O-ring or the like is used as the seal material.

The opening 3 is formed in the upper wall of each of the collecting portions 15 and 16.
1 and 32 are formed, the communication pipe 20 has openings 3
Openings 33, 34 of the same shape are formed so as to overlap with 1, 32. The openings 31 and 32 extend in the cylinder row direction, and the opening edges of the openings 31 and 32 are the branch pipes 1 in the plan view (FIG. 3).
The center line O ₁ , which is located at the front and rear ends of 3, 14
It is arranged on the outer side of O ₂ , O ₅ , and O ₆ , so that the opening area of the communicating pipe 20 with respect to the collecting portions 15 and 16 is sufficiently secured.

As shown in FIG. 10, the communication pipe 20 has a flat box shape, and a partition wall 27 defines therein a first series passage 21 and a second communication passage 22 having different opening cross-sectional areas. To be done. Each of the communication passages 21 and 22 has a substantially rectangular cross-sectional shape, and is formed in different sizes.

Further, the first ceiling wall portion 21a defining the first series passage 21 is formed lower than the second ceiling wall portion 22a defining the second communication passage 22 with a step 28. It is possible to reduce the air resistance of the vehicle by tilting the engine hood of the vehicle low from the rear side to the front side of the vehicle.

Butterfly type first and second control valves 23 and 24 are provided in the communication passages 21 and 22, respectively. The control valves 23 and 24 are rectangular valve bodies 23a and 24a, and valve shafts 23b and 2 that rotatably support the valve bodies 23a and 24a.
4b and is opened and closed via actuators 25 and 26 connected to the valve shafts 23b and 24b. Each valve shaft 23
Link plates 39 and 40 are connected to the ends of b and 24b protruding from the communication pipe 20, and the rods 25 of the actuators 25 and 26 are connected to the link plates 39 and 40, respectively.
a and 26a are connected. Each actuator 25, 26
Is configured to open and close each control valve 23, 24 in accordance with the operating condition to change the passage area of the communication pipe 20 in a stepwise manner.

Next, the operation will be described.

Intake air taken in from an air cleaner (not shown) is introduced from each throttle valve 10 into each introduction pipe 17,1.
After being sent to each of the collecting parts 15 and 16 through 8, the pipe is sucked into the cylinders that sequentially enter the intake stroke through the branch pipes 13 and 14. In a predetermined low rotation speed range, the control valves 23 and 24 are both closed to cut off the communication between the collecting portions 15 and 16, so that the pulsation energy of intake air is used to perform resonance supercharging.

2 for guiding intake air from the throttle valve 10
Since the two introduction pipes 17 and 18 are connected to the central portions of the collecting portions 15 and 16, it is possible to make the intake passage length connecting the throttle valve 10 and the intake valve 8 of each cylinder uniform, and in the low rotation speed range, the above resonance occurs. By supercharging, the suction efficiency of each cylinder can be uniformly increased.

Only one of the control valves 23 and 24 is selectively opened in a predetermined medium speed range, and both control valves 23 and 24 are opened in a predetermined high speed range. 15,
By gradually changing the opening area that communicates 16 with each other, inertia supercharging using the air column inertia of intake air is switched. FIG. 11 shows an experimental result obtained by measuring generated torque characteristics according to opening / closing of each control valve 23, 24. Based on this characteristic, each control valve 23 is controlled so that the highest generated torque is obtained according to the rotation speed. , 24 are controlled to be opened and closed.

The second communicating passage 22 having a relatively large cross-sectional area is arranged rearward of the first continuous passage 21 and exerts a force toward the rear of the engine which is given to the intake air flow passing through the introduction pipe parallel portions 17b and 18b. Utilizing this, the intake flow is promoted to flow into the second communication passage 22, and the intake efficiency at high speed is enhanced.

The intake manifold 6 includes branch pipes 13 and 14
Crossing portions 13B and 14B of the pipes 1 and 2 in parallel with each other, and introducing pipes 1 from the branch pipes 13 and 14 to the collecting portions 15 and 16 respectively.
Since the intake passage extends horizontally without bending in the vertical direction to 7 and 18, the curvature of the intake passage can be minimized to suppress the intake resistance.

Upstream portions 13A, 14 of the branch pipes 13, 14
Since the cross-sectional shapes of A and the downstream portions 13C and 14C are each formed into an elliptical shape having a major axis in the cylinder row direction, each branch pipe 1
The communication pipe 2 is located above the branch pipes 13 and 14 while suppressing the overall height of the engine while ensuring a sufficient passage cross-sectional area of the pipes 3 and 14.
It is possible to set 0.

Intersections 13B and 14B of the branch pipes 13 and 14
Since the cross-sectional shape of the cross section is formed into an oval shape having a minor axis in the cylinder row direction, the passage cross-sectional area of the intersecting portions 13B and 14B is limited by the distance between the branch pipes 13 and 14 that are adjacent to each other. It is possible to avoid the above and secure a sufficient passage cross-sectional area.

[0040]

As described above, according to the present invention, in the intake device provided in the multi-cylinder internal combustion engine having the left and right banks facing each other in the V-shape, the branch pipes communicating with the intake ports of the cylinders of the left and right banks are parallel to each other. Is installed so as to intersect with each other, and two collecting portions for collecting the branch pipes connected to the cylinders whose ignition order is not continuous are provided with each other, and connected to the upstream portion connected to the collecting portion of each branch pipe and the intake port Since the cross-sectional shape of the downstream portion is formed into an elliptical shape having a major axis in the cylinder row direction, and the cross-sectional shape of the intersection connecting the upstream portion and the downstream portion is formed into an oval shape having a minor diameter in the cylinder row direction, It becomes possible to suppress the overall height of the engine while ensuring a sufficiently large passage cross-sectional area of the branch pipe, and it is possible to suppress the engine hood line of the vehicle to a low level. Further, by suppressing the height of each branch pipe, it becomes possible to provide a communication pipe located above the branch pipe and communicating each collecting portion. By opening and closing the communication pipes that connect each collecting part according to the engine operating conditions, the resonance supercharging effect is enhanced in the low speed range and the inertia supercharging effect is enhanced in the high speed range, and the wide range of speeds is achieved. Inhalation efficiency can be maintained.

[Brief description of drawings]

FIG. 1 is a front view of an engine showing an embodiment of the present invention.

FIG. 2 is likewise an overall front view of the engine.

FIG. 3 is a plan view of the intake device of the same.

FIG. 4 is a plan view of the same engine.

FIG. 5 is a side view of the same engine.

FIG. 6 is an exploded perspective view of the intake device of the same.

7 is a sectional view taken along line AA of FIG. 1.

FIG. 8 is a sectional view taken along line BB of FIG.

FIG. 9 is a sectional view taken along the line CC of FIG.

FIG. 10 is a perspective view of the communication pipe.

FIG. 11 is a torque characteristic diagram of the engine.

FIG. 12 is a front view of an engine showing a conventional example.

[Explanation of symbols]

 13 Branch pipe 14 Branch pipe 13A Upstream part 14A Upstream part 13B Intersection part 14B Intersection part 13C Downstream part 14C Downstream part 15 Collecting part 16 Collecting part 20 Communication pipe 23 First control valve 24 Second control valve

Claims (2)

[Claims] 1. In an intake system provided in a multi-cylinder internal combustion engine having left and right banks facing each other in a V-shape, branch pipes communicating with intake ports of the cylinders of the left and right banks are arranged so as to cross each other in parallel. Two collecting parts are provided for collecting the branch pipes connected to the cylinders whose ignition order is not continuous, and the cross-sectional shape of the upstream part connected to the collection part of each branch pipe and the downstream part connected to the intake port is the cylinder. An intake system for an internal combustion engine, wherein the cross section of an intersection connecting an upstream portion and a downstream portion is formed into an elliptical shape having a short diameter in the cylinder row direction, and an elliptical shape having a long diameter in the row direction. 2. A communication pipe for communicating each collecting portion is provided above each branch pipe, and a control valve for opening and closing each communication pipe according to engine operating conditions is provided. 1. An intake system for an internal combustion engine according to 1.