JPH0347415B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an intake system for a multi-cylinder internal combustion engine, and particularly to an intake system for a multi-cylinder internal combustion engine. In a multi-cylinder internal combustion engine, multiple low-speed intake passages and multiple high-speed intake passages that are shorter than these low-speed intake passages are connected in parallel to multiple intake ports of each cylinder, and the low-speed and high-speed operating states of the engine are connected in parallel. The present invention relates to an intake system that selectively operates both of the intake passages according to the conditions, thereby constantly increasing the filling efficiency of the engine due to the intake inertia effect and producing high output.

Conventionally, as an intake system for an internal combustion engine, the entrances of the low-speed and high-speed intake passages are opened to a common intake chamber, and the high-speed intake passage has an open/close valve that closes in the low-speed operating range of the engine and opens in the high-speed operating range. Types with a valve are known. Such an intake system has the advantage that the intake air amount of the engine can be controlled by one intake air amount control device, but because the low-speed and high-speed intake paths of different lengths are opened into a common intake chamber, The intake chamber will inevitably be formed large.

By the way, the present inventors have found through various test studies that the size of the volume of the intake chamber has the following influence on the operating performance of the engine.

(1) If the volume of the intake chamber exceeds a certain size, engine idling may become unstable when the low-speed intake passage is activated, or engine responsiveness may decrease when sudden acceleration is performed from idling.

(2) When one intake chamber is commonly used for each cylinder in a multi-cylinder internal combustion engine, if the volume of the intake chamber is too small, the intake pulsations of each cylinder will interfere with each other, reducing the filling efficiency. The desired high output performance will no longer be achieved.

(3) When performing resonance supercharging in a multi-cylinder internal combustion engine, the resonance point (engine speed) is determined by the volume of the intake chamber.

Based on these results, in order to always improve the operating performance of the engine, it is desirable to be able to adjust the volume of the intake chamber to be large or small depending on the high-speed and low-speed operating ranges of the engine.

The present invention satisfies such requirements in a V-type multi-cylinder internal combustion engine, and can easily form each of the low-speed and high-speed intake passages to predetermined lengths without interfering with each other, and furthermore, the It is an object of the present invention to provide the above-mentioned intake device, which can make the entire engine more compact by effectively utilizing space between rows.

To achieve this objective, the present invention connects a plurality of low-speed intake passages in parallel to a plurality of intake ports of each cylinder row and a plurality of high-speed intake passages that are shorter than these low-speed intake passages. The inlet of each of the low-speed intake passages is opened in a first intake chamber arranged outside the valley between the rows and connected to the intake air amount control device, and the inlet of each low-speed intake passage is opened in the first intake chamber arranged outside the valley between the cylinder rows and connected to the intake air amount control device. to open the inlets of each of the high-speed intake passages to a second intake chamber that communicates with the first intake chamber, and the communication passage and each of the high-speed intake passages are provided with valves that are closed in a low-speed operating range of the engine and opened in a high-speed operating range. A main on-off valve and a auxiliary on-off valve are interposed respectively.

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

The internal combustion engine shown in Fig. 1 is a V-type six-cylinder engine, so two
Three cylinders 1 are arranged in each of the two cylinder rows C ₁ and C ₂ in the axial direction (front and back direction in FIG. 1) of a crankshaft (not shown).

Since the structures of both cylinder rows C ₁ and C ₂ are approximately symmetrical, only the structure of the right cylinder row C ₂ will be explained. The upper surface of the cylinder block 2 in which the cylinder 1 is formed is connected to the cylinder head via the gasket 4. 3 is polymerized and bound together. A piston 5 is slidably fitted into the cylinder 1, and a combustion chamber 6 is recessed in the bottom surface of the cylinder head 3 facing the piston 5.

The ceiling surface 7 of the combustion chamber 6 is made up of two slopes 7a and 7b that descend toward both left and right sides from a ridge line L extending in the direction in which the three cylinders 1 are arranged (see FIG. 1A), and both cylinder rows C ₁ A pair of intake valve ports 8, 8 are provided on the slope 7b located on the valley V side between , C ₂ , and a pair of exhaust valve ports 9, 9 are provided on the slope 7b on the opposite side.
are lined up along the ridge line L and opened. These intake valve ports 8, 8 and exhaust valve ports 9, 9 are opened and closed by a pair of intake valves 11, 11 and an exhaust valve 12, 12, respectively, which are driven by a valve mechanism 10. One spark plug 13 surrounded by these four valves 11, 11; 12, 12 is screwed onto the cylinder head 3, and its electrode faces the center of the ceiling surface 7 of the combustion chamber 6.

One pair each of intake valve ports 8, 8 and exhaust valve ports 9, 9
are connected to the common intake port 14 and exhaust port 15, respectively, and the entrance of the intake port 14 is connected to the valley V
The exhaust port 15 opens at the upper surface of one side of the cylinder head 3 adjacent to the cylinder head 3, and the outlet of the exhaust port 15 opens at the other side of the cylinder head 3.

In Fig. 2, the three intake ports 14 of the left cylinder row _C1 are arranged in order from above: first, second, and third.
They are called intake ports 14 ₁ , 14 ₂ , 14 ₃ , and the three intake ports 14 of the right cylinder row C ₂ are called fourth, fifth, sixth intake ports 14 ₄ , 14 ₅ , in order from above.
Let's call it 14 ₆ . An intake manifold M for distributing and supplying air or air-fuel mixture to these intake ports is arranged along a valley V between both cylinder rows C ₁ and C ₂ .

The intake manifold M has first to sixth intake ports 14 1 to 1, as shown in FIGS. ₂ to 10.
The first to sixth low-speed intake passages 16 ₁ to 16 ₆ connected to the inlets of No. 4 ₆ , respectively, and these low-speed intake passages 16 ₁
~16 ₆ in parallel with the first to sixth intake ports 14 ₁ to 1
1 to 6 high-speed intake passages 17 ₁ to 17 ₆ connected to the inlets of No. 4 ₆ , respectively, and the first to sixth low-speed intake passages 1
A common first intake chamber 18 1 in which the inlets a ₁ to a ₆ of 6 ₁ to _{16 6} open, and the first to sixth high-speed intake passages 17 ₁ to
17 1 common second intake chamber 1 with ₆ inlets open
8 ₂ and first and second communication passages 19 ₁ and 19 ₂ that communicate in parallel between both the intake chambers 18 ₁ and 18 ₂ , and the first and second communication passages 19 ₁ and 19 _{2 ,} respectively. the first and second main on-off valves 20 ₁ and 20 ₂ and the first to sixth auxiliary on-off valves 21 1 to 21 ₆ interposed in the first to sixth high-speed intake passages _{17 1} to 17 ₆ , respectively. We are prepared.

Thus, the cross-sectional area of each of the high-speed intake passages 17 ₁ to 17 ₆ is set larger than that of the corresponding low-speed intake passage 16 ₁ to 16 ₆ . Further, the total length of each of the intake ports 14 ₁ to 14 ₆ and the low-speed intake passages 16 ₁ to 16 ₆ that communicate with each other is a first length L ₁ that can maximize the charging efficiency in the low-speed operating range due to the intake inertia effect. is set to
The total length of the intake ports 14 ₁ to 14 ₆ and the high-speed intake passages 17 ₁ to 17 ₆ that communicate with each other is set to a second length L ₂ that can maximize the charging efficiency in the high-speed operation range due to the intake inertia effect. be done. Therefore, this second length _L2 is set to be sufficiently shorter than the first length _L1 .

Further, the first and second communication passages 19 ₁ and 19 ₂ are formed to be thicker and shorter than each of the high-speed intake passages 17 ₁ to 17 ₆ .

In order to facilitate processing, assembly, maintenance, etc., the intake manifold M is disposed in the valley V between both cylinders C ₁ and C ₂ and is connected to both cylinder rows C 1 , C ₂ by a plurality of bolts 22 , 22 . The first block _B1 is connected to the cylinder head 3 of _C2 , and the first block B1 is connected to the third and sixth intake ports ₁₄₃ , ₁₄₆ of the valley V by a plurality of bolts 23, 23... 1 block
A second block _B2 is connected to _B1 , and a third block _B3 is connected to the lower surface of the first block _B1 in the valley V by a plurality of bolts 25, 25, with the valve support plate 24 in between. It is divided into

and the first to third high-speed intake passages 17 ₁ to 1
7 ₃ and the fourth to sixth high speed intake passages 17 ₄ to 17 ₆ are
As clearly shown in FIG. 9, the first block B ₁ , the valve support plate 24 and the third block B ₃ are formed in an inverted U shape and intersect with each other, and the first to third blocks 6 Low speed intake passage 16 ₁ ~ 16 ₆
is formed across the first and second blocks B ₁ and B ₂ so as to pass above each of the high-speed intake passages 17 ₁ to 17 ₆ ,
Further, the first intake chamber 18 ₁ is formed in the second block B ₂ , and the second intake chamber 18 ₂ is elongated and formed in the third block B ₃ so as to extend substantially over the entire length of the valley V. The two communication passages 19 ₁ , 19 ₂ are formed in the first block B ₁ , and the first and second main on-off valves 20 ₁ , 20 ₂ and the first to sixth auxiliary on-off valves 21 ₁
21 ₆ is pivotally supported on the valve support 24 . Thus,
All low-speed intake passages 16 ₁ to 16 ₆ , all high-speed intake passages 17 ₁
~17 ₆ and the second intake chamber 18 ₂ are both cylinder rows C ₁ ,
It is arranged in the valley V between _C2 , and only the first intake chamber ₁₈₁ is arranged outside the valley V. As described above, when the second intake chamber 18 ₂ is formed to have a length that extends approximately to the entire length of the valley V, the second intake chamber 18 ₂ is connected to the first to sixth intake ports 14 _{1 .}
The first to sixth high-speed intake passages 17 ₁ communicating with ~14 ₆
17 The lengths of ₆ can be made to be exactly the same length.

The first to sixth low-speed intake passages 16 ₁ to 16 ₆ are arranged so as to surround the first intake chamber _{18 1} and are coupled to each other so as to share a boundary _wall . In order to make the lengths approximately equal, the opening positions of the inlets a ₁ to a ₆ of each of the low-speed intake passages 16 ₁ to 16 ₆ to the first intake chamber 18 ₁ are adjusted according to the distances to the corresponding intake ports ₁₄ 1 to 14 ₆ . Selected.

The first intake chamber 18 ₁ has a corrugated inner circumferential wall 26 connected to each other of the six low-speed intake passages 16 ₁ to 16 ₆ surrounding these, and a blocking wall 27 connected to one end of the inner circumferential wall 26 as described above. defined by. In this way, there is no need to provide a special box for forming the first intake chamber 18 ₁ , and the structure is simple.

The other end of the first intake chamber ₁₈₁ is opened as an inlet 28, and an intake air amount control device 29 for adjusting the amount of intake air or the amount of air mixture is attached to the inlet 28.

The valve support body 24 rotatably supports a pair of left and right valve shafts 30 ₁ and 30 ₂ that extend parallel to a crankshaft (not shown), and the left valve shaft 30 ₁ has a first main opening/closing valve 20 ₁ and a fourth ~Sixth auxiliary on-off valves 21 ₄ to 21 ₆ are installed, and a second main on-off valve 20 ₂ is attached to the right valve shaft 30 ₂
And first to third sub-opening/closing valves 21 ₁ to 21 ₃ are attached.

As shown in FIG. 1, both valve shafts 30 ₁ and 30 ₂ are provided with operating levers 31 ₁ and 31 ₂ at their outer ends, respectively, and these operating levers 31 ₁ and 31 ₂ are connected to each other via an interlocking link 32. coupled and actuator 33
connected to. This actuator 33 normally holds the full open/close valve in a closed position, and opens the full open/close valve in response to the engine reaching a predetermined high rotational speed state.

Various types of actuator 33 can be adopted, such as a negative pressure type and an electromagnetic type, but in the case of a negative pressure type, the full-open/close valve is closed by the boost negative pressure of the engine and opened by spring force. It is desirable to configure

In the figure, 34 is an air cleaner of the intake control device 29, and 35 ₁ to 35 ₆ are fuel injection nozzles mounted on the intake manifold M so as to face each of the intake ports 14 ₁ to 14 ₆ . Of course, this is not necessary if the quantity control device 29 is a vaporizer.

Next, the operation of this embodiment will be explained. When the engine is operating at low speed, the actuator 33 is in an inactive state and all of the main and sub-opening valves 20 ₁ , 20 ₂ ; 21 ₁ to 2
1 ₆ is closed, the high-speed intake passages 17 ₁ to 17 ₆ are cut off, and communication between the first and second intake chambers 18 ₁ and 18 ₂ is interrupted.

Therefore, the air or mixture that is metered by the intake air amount control device 29 and sucked into the first intake chamber 18 ₁ during the intake stroke of the engine is transferred from the chamber 18 ₁ to the first to sixth low-speed intake passages 16 1 to 16 ₁ . 16 ₆ and is sucked into the corresponding cylinder 1 through the first to sixth intake ports 14 ₁ to 14 ₆ .

Thus, as described above, each of the intake ports 14 ₁ to 14 ₆ and the low-speed intake passages 16 ₁ to 16 ₆ communicate with each other.
The total length of L is set to a relatively long first length _L1 that can maximize the charging efficiency due to the intake inertia effect during low-speed engine operation, so that it is possible to satisfy the low-speed output performance of the engine. can.

When the engine enters a predetermined high-speed operating state, actuator 3
3 is activated and the main and auxiliary full open/close valves 20 ₁ , 20 ₂ ; 21
₁ to 21 ₆ are opened, and the first and second intake chambers 18 ₁ , 1
8 ₂ and the first to sixth high-speed intake passages 17 ₁ to 17 ₆ respectively. Then, during the intake stroke of the engine, the air or mixture sucked into the first intake chamber 18 ₁ from the intake air amount control device 29 immediately passes through the first and second communication passages 19 ₁ and 19 ₂ to the second intake chamber 18 1 .
The intake chamber expands to 18 ₂ , and each low-speed intake passage 1
6 ₁ ~ 16 The first ~ which has much lower intake resistance than ₆
distributed to the sixth high-speed intake passages 17 ₁ to 17 ₆ ;
The air is sucked into the corresponding cylinder 1 through the sixth intake ports 14 ₁ to 14 ₆ .

Therefore, as mentioned above, each of the first
~ The total length of the sixth intake ports 14 ₁ to 14 ₆ and the first to sixth high speed intake passages 17 ₁ to 17 ₆ is a relatively long length that can maximize the charging efficiency due to the intake inertia effect during predetermined high speed operation of the engine. Since the second length _L2 is set to be short, it is possible to satisfy the high output performance of the engine.

Moreover, during low speed operation, the first and second main on-off valves 2
By closing the valves 0 ₁ and 20 ₂ , the second intake chamber 18 ₂ is stopped and only the first intake chamber 18 ₁ is communicated with the first to sixth low-speed intake passages 16 ₁ to 16 ₆ , and both main openings and closings are performed during high-speed operation. By opening the valves 20 ₁ and 20 ₂ , both intake chambers 18 ₁ ,
18 ₂ are communicated with the first to sixth high-speed intake passages 17 ₁ to 17 ₆ , the effective volume of all the intake chambers 18 ₁ and 18 ₂ is automatically controlled to be small during low-speed operation and large during high-speed operation. . Therefore, in the low-speed driving range, it is possible to stabilize idling and improve acceleration from idling, and in the high-speed driving range, each high-speed intake passage is not interfered with by the intake pulsation of other high-speed intake passages. Since the desired intake inertia effect can be exerted, the output of the engine can be reliably improved.

Furthermore, if the total volume of the first and second intake chambers 18 ₁ and 18 ₂ is set to perform resonance supercharging in the desired high-speed operating range of the engine, the charging efficiency will further increase and the engine output will be further improved. can be achieved.

In the above embodiment, two main on-off valves 20 ₁ , 2
0 ₂ is used, but if the communication path between the two intake chambers 18 ₁ and 18 ₂ is made thicker, the number of main opening/closing valves can be reduced to one.

As described above, according to the present invention, in a V-type multi-cylinder internal combustion engine in which a pair of cylinder rows are arranged in a V-shape, a plurality of low-speed intake passages 1 are connected to a plurality of intake ports of each cylinder row. , a plurality of high-speed intake passages shorter than these low-speed intake passages are connected in parallel, and the inlets of each of the low-speed intake passages are opened in a first intake chamber connected to the intake air amount control device, and the 1st
The entrance of the high-speed intake passage is opened in a second intake chamber that communicates with the intake chamber, and a main opening/closing valve is provided in the communication passage and each of the high-speed intake passages, which closes in a low-speed operating range of the engine and opens in a high-speed operating range. and auxiliary opening/closing valves, the effective volume of the total intake chamber is automatically switched from small to large when the operation is switched from each low-speed intake path to the high-speed intake path, and as a result, the effective volume of each low-speed intake path is During operation, it is possible to obtain the desired low-speed output performance of the engine, stabilize idling, and improve acceleration from idling. Also, when each high-speed intake path is activated, interference with intake pulsation of other high-speed intake paths is achieved. The desired high-speed output performance of the engine can be obtained while avoiding this.

In addition, the first intake chamber connected to each low-speed intake path is placed outside the valley between both cylinder rows, and the second intake chamber connected to each high-speed intake path is placed in the valley, so that the distance between both intake chambers is Due to the difference between the low-speed and high-speed intake passages, it is possible to easily form each of the low-speed and high-speed intake passages to desired lengths without interfering with each other. Moreover, due to the above structure, in addition to the second intake chamber, the low-speed and high-speed intake passages can be formed in the valley. Therefore, the overall height of the engine does not become very high, which contributes to making it more compact.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, and FIG. 1 is a longitudinal sectional front view of the main parts of the entire V-type multi-cylinder internal combustion engine, FIG. 1A is a bottom view of the cylinder head of the engine shown in FIG. 1, and FIG. is a plan view of the main part of Figure 1, Figure 3 is a side view of the intake manifold in Figure 1, Figures 4 and 5 are
Figures 6 and 6 are sectional views taken along lines -, -, and - in Figure 2, and Figures 7, 8, 9, and 10 are sectional views taken along lines -, -, -, and - line sectional view. C ₁ , C ₂ ...Left and right cylinder rows, M...Intake manifold, V...Valley, 1...Cylinder, 14 ₁ to 14 ₆
...Intake port, 16 ₁ to 16 ₆ ...Low speed intake path, 17
₁ to 17 ₆ ... High speed intake passage, 18 ₁ , 18 ₂ ... First and second intake chambers, 19 ₁ , 19 ₂ ... Communication passage, 20 ₁ , 20 ₂
...Main opening/closing valve, 21 ₁ to 21 ₆ ... Sub-intake valve, 33... Actuator.

Claims (1)

[Claims] 1. In a V-type multi-cylinder internal combustion engine in which a pair of cylinder rows each having a plurality of cylinders arranged in the axial direction of the crankshaft are arranged in a V-shape, a plurality of cylinders are connected to the plurality of intake ports of each cylinder row. A low-speed intake passage and a plurality of high-speed intake passages shorter than these low-speed intake passages are connected in parallel, and each of the above-mentioned Opening the entrance of the low-speed intake passage, and opening the entrance of each of the high-speed intake passages to a second intake chamber that is disposed in a valley between both cylinder rows and communicates with the first intake chamber via a communication passage. , an intake system for a multi-cylinder internal combustion engine, wherein a main on-off valve and a sub-on/off valve that close in a low-speed operating range of the engine and open in a high-speed operating range are interposed in the communication passage and each of the high-speed intake passages, respectively. .