JPH0222231B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Object of the Invention (1) Industrial Field of Application The present invention includes a cylinder head having a combustion chamber and an intake port connected to the combustion chamber. The present invention relates to an internal combustion engine equipped with an intake manifold that communicates with the engine.

(2) Prior Art Conventionally, in this type of internal combustion engine, in order to facilitate the casting of the intake manifold, it has been divided into at least two parts. The intake manifold is selected without regard to the mounting surface to the cylinder head (for example, see Japanese Patent Application Laid-Open No. 54-74021), so when machining the intake manifold, the mounting surface to the cylinder head and the two parts are selected. The joint surfaces must be cut separately.

(3) Problems to be solved by the invention By the way, in a V-type internal combustion engine, the joint surfaces of the upper and lower halves of the intake manifold and the mounting surface of the upper half to the cylinder head are flush with each other. Therefore, a method has already been proposed in which the above-mentioned joint surface and mounting surface of the upper half can be cut at the same time with the same tool (see, for example, Japanese Patent Publication No. 33-9051). The lower half functions as an intake pipe that directly communicates with the intake port on the cylinder head side through the joint surface with the cylinder head, so the lower end of the lower half is connected between the pair of cylinder rows forming a V shape. It is difficult to make effective use of the space by protruding into the valley space, and the upper half above the lower half has to be placed in a high position, so the entire engine is large. In addition, there are problems such as the center of gravity of the intake manifold becoming higher and being unable to stably support it.

The present invention has been proposed in view of the above, and an object of the present invention is to provide an internal combustion engine that can solve all of the problems of the conventional engines.

B. Structure of the Invention (1) Means for Solving the Problems In order to achieve the above object, the present invention has a pair of cylinder rows arranged in a V-shape, and a cylinder head of each cylinder row. In this internal combustion engine, a combustion chamber and an intake port connected to the combustion chamber are formed, and a common intake manifold is connected to each intake port, and the intake manifold is connected to the cylinder heads of the pair of cylinder rows. an upper half portion whose lower surfaces on both sides are polymerized and bonded to a pair of support surfaces formed flush with each other; and a lower half whose lower end protrudes into the valley between both cylinder rows, and a section where the upper half and the cylinder head overlap each other between the intake passages in the upper half and the corresponding intake ports. For direct communication, an outlet of the intake passage is opened on the lower surface of both sides of the upper half, and an entrance of the intake port is opened on both the support surfaces of the cylinder head.

(2) Action The lower surfaces on both sides of the upper half of the intake manifold, which are the mounting surfaces for both cylinder heads, and the joining surface of the lower half of the upper half are flush with each other, and the same tool is used to remove the lower surfaces in one step. It can be cut into.

By directly communicating the intake passage in the upper half of the intake manifold with the intake port on the cylinder head side, there is no need to directly communicate the intake passage in the lower half with the intake port on the cylinder head side. Since the lower half can be arranged to protrude long downward from the support surface of the cylinder head that opens the intake port, the valley space between both cylinder rows can be effectively used as the installation space for the lower half. In addition, the center of gravity of the intake manifold can be set as low as possible.

(3) Embodiment 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 the two cylinder rows C ₁ and C ₂ are almost 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 consists 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.
), a pair of intake valve ports 8, 8 are located on the slope 7a located on the valley V side between both cylinder rows C ₁ and C ₂ , and a pair of exhaust valve ports 9, 8 are located on the slope 7b on the opposite side.
9 open along the ridge line L, respectively. These intake valve ports 8, 8 and exhaust valve ports 9, 9 are connected to the valve mechanism 10.
The intake valves 11, 11 and the exhaust valves 12, 12 are respectively opened and closed by a pair of intake valves 11, 11 and an exhaust valve 12, 12, which are driven by a pair of intake valves 11, 11 and an exhaust valve 12, 12, respectively. 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.

Each pair 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 a support surface f2 provided on 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
6 ₁ to 16 ₆ , one common first intake chamber 8 ₁ in which inlets a ₁ to a ₆ are opened, and first to sixth high speed intake passages 17 ₁ to 1
One common second intake chamber 18 ₂ where the inlets of 7 ₆ are open.
, first and second communication passages 19 ₁ , 19 ₂ which connect both the intake chambers 18 1 , 18 2 in a closed line, and first and second communication passages 19 ₁ , 19 ₂ .
The first and second main on-off valves 20 ₁ and 20 ₂ are interposed in the communication passages 19 ₁ and 19 ₂ , respectively, and the first to second main on-off valves are interposed in the first to sixth high-speed intake passages 17 ₁ to 17 ₆ , respectively. It is equipped with six sub-opening/closing valves 21 ₁ to 21 ₆ .

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 14 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 cylinder rows C ₁ and C ₂ and has a plurality of bolts 22, 22...
, the first block B 1 whose lower surfaces F ₂ on both sides are overlapped and bonded to the support surfaces f ₂ of the cylinder heads 3 of both cylinder rows C _{1 and} C ₂ , and the third and sixth intake ports 14 in the valley V. A second block B2 is arranged on the outside of _{the 3} , 14 _{, 6} side and is connected to the first block _B1 by a plurality of bolts 23, 23...;
The third block _B3 is connected to the lower surface of the block B1 by a plurality of bolts 25, 25, . . . with the valve support plate ₂₄ in between.

Thus, the first and second blocks B ₁ and B ₂ constitute the upper half Mu of the intake manifold M, the valve holding plate 24 and the third block B ₃ constitute the lower half Ml, and the The joint surface F ₁ of the half part Mu with the lower half part Ml, that is, the joint surface F ₁ with the valve support plate 24 of the first block B ₁
and the lower surfaces F ₂ and F ₂ on both sides, which are a pair of mounting surfaces of the upper half Mu to the left and right cylinder heads 3, 3, are arranged flush with each other.

The low and high speed intake passages 16 ₁ to 16 ₆ , 17 ₁ to 1
The common outlets of the _upper half Mu and the cylinder head 3 are connected directly to the inlet of the corresponding intake port 14 through the overlapping surface of the upper half Mu and the cylinder head 3.
It is opened at the lower surface _F2 on both sides of Mu. 1st
~The third high speed intake passages ₁₇₁ ~ ₁₇₃ and the fourth~sixth high speed intake passages ₁₇₄ ~ ₁₇₆ are arranged in an inverted U shape and intersect with each other, as shown in FIG. 1 block B ₁ , the valve support plate 24 and the third block B ₃ , and the first to sixth low speed intake passages 16 ₁ to 16 ₆ are connected to each high speed intake passage 17 _{1 .}
~ ₁₇₆ is formed across the first and second blocks _B1 and _B2 , and the first intake chamber 1
8 ₁ is formed in the second block B ₂ and also in the second block B 2 .
The intake chamber 18 ₂ is elongated and formed in the third block B ₃ so as to cover substantially the entire length of the valley V, and the first and second communicating passages 19 ₁ and 19 ₂ are formed in the first block B ₁ . 1. The second main on-off valves 20 ₁ , 20 ₂ and the first to sixth auxiliary on-off valves 21 ₁ to 21 ₆ are the valve support plate 2
4. Thus, the total low speed intake passage 16 ₁
~ ₁₆₆ , all the high-speed intake passages ₁₇₁ to ₁₇₆ , and the second intake chamber ₁₈₂ are arranged in the valley V between both cylinder rows _C1 , _C2 , and only the first intake chamber ₁₈₁ is located in the valley V. placed outside. As described above, when the second intake chamber ₁₈₂ is formed to have a length that spans approximately the entire length of the valley V, the second intake chamber 182
The lengths of the first to sixth high-speed intake passages 17 1 to 17 ₆ that communicate with _the first to sixth intake ports _{14 1} to 14 ₆ can be made exactly equal.

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.

As described above, the first intake chamber 18 ₁ has a corrugated inner circumferential wall 26 of the six low-speed intake passages 16 ₁ to 16 ₆ that surround these, and a blocking wall 27 that is continuous to one end of the inner circumferential wall 26 . 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.

A pair of left and right valve shafts 30 ₁ , 30 ₂ extending parallel to a crankshaft (not shown) are rotatably supported on the valve support plate 24 , and the left valve shaft 30 ₁ has a first main on-off valve 20 1 and a fourth main on-off valve 20 ₁ , 30 2 . ~Sixth auxiliary on-off valves ₂₁₄ to ₂₁₆ are installed, and a second main on-off valve 2 is attached to the right valve shaft _302.
0 ₂ and first to third auxiliary on-off valves 21 ₁ to 21 ₃ are installed.

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,
It is desirable to configure the valve to open with spring force.

In addition, in the figure, 34 is an air cleaner of the intake air amount control device 29, and 35 ₁ to 35 ₆ are each intake port 14 ₁ to 14 ₆
These are combustion injection nozzles mounted on the intake manifold M so as to face the intake manifold M, and these nozzles are of course unnecessary when the intake air amount control device 29 is a carburetor.

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 the main and sub-opening valves 20 ₁ , 20 ₂ ; 21
₁ to 21 ₆ are closed, all high-speed intake passages 17 ₁ to 17 ₆ are shut off, and the first and second intake chambers 18 ₁ and 18 _{2 are} closed.
It's cutting off communication.

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 filling rate due to the intake inertia effect during low-speed operation of the engine, so that the low-speed output performance of the engine can be satisfied. .

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 mixer 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 air 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 comparison 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 relatively 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 is communicated with the first to sixth high-speed intake passages 17 ₁ to 17 ₆ , the effective volumes of all the intake chambers 18 ₁ and 18 ₂ are automatically controlled to be small during low-speed operation and large during high-speed operation. Therefore, in the low-speed operating range, it is possible to stabilize idling and improve acceleration from idling, and in the high-speed operating 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.

In the above-mentioned intake manifold M, the joint surface F ₁ of the first block B ₁ with the valve support plate 24 and the lower surfaces F 2 on both sides, which are the pair of mounting surfaces of the first block B ₁ to the left and right cylinder heads 3 , _{3 .} , F ₂ are arranged on the same plane, the three surfaces F ₁ , F ₂ , F ₂ can be cut at once with the same tool, thereby improving the machining efficiency and machining accuracy of the intake manifold M.

C. Effects of the Invention As described above, the present invention has a pair of cylinder rows arranged in a V-shape, and the cylinder head of each cylinder row has a combustion chamber and an intake port connected to the combustion chamber. In an internal combustion engine in which a common intake manifold is connected to each intake port of the internal combustion engine, the intake manifold comprises:
an upper half part whose lower surfaces on both sides are polymerized and bonded to a pair of support surfaces formed flush with each other on the cylinder heads of the pair of cylinder rows; and a lower half part that is connected at one joint surface and has a lower end protruding into the valley between both cylinder rows, and the upper half part is connected between the intake passages in the upper half part and the intake ports corresponding thereto. In order to directly communicate with each other through the overlapping surfaces of the cylinder head and the cylinder head, an outlet of the intake passage is opened in the lower surface of both sides of the upper half, and an inlet of the intake port is opened in the support surfaces of the cylinder head. Therefore, the upper half of the intake manifold and the lower surfaces on both sides, which are the mounting surfaces for both cylinder heads,
The upper half can be cut flush with the lower half in one step using the same tool, which can greatly contribute to improving the machining efficiency and machining accuracy of the intake manifold. Moreover, since the intake manifold directly communicates the intake passage in its upper half with the intake port on the cylinder head side, it is no longer necessary to directly communicate the intake passage in its lower half with the intake port on the cylinder head side.
Therefore, it is possible to dispose the lower half protruding downward for a long time from the support surface of the cylinder head where the intake port opens, so that the valley space between both cylinder rows can be used as the installation space for the lower half. It can be used effectively, contributing to the downsizing of the engine, and the center of gravity of the intake manifold can be set as low as possible, allowing the manifold to be stably supported on the cylinder head by a relatively small number of supporting members. can be done.

As in the embodiment, the intake manifold is provided with two intake passages with different intake inertia effects and an on-off valve for opening and closing one of the intake passages, and also constitutes a part of the lower half. If the opening/closing valve is disposed within a valve support plate whose upper end surface is joined to the upper half, the lower half of the manifold will be relatively bulky, but this can be used as a dead space between both cylinder rows. It can be easily placed in the valley space.

[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, F ₁ ... joint surface,
F ₂ ... side lower surface, f ₂ ... support surface, M ... intake manifold, Mu ... upper half, Ml ... lower half.

Claims (1)

[Scope of Claims] 1. It has a pair of cylinder rows arranged in a V-shape, and a combustion chamber and an intake port connected to the combustion chamber are formed in the cylinder head of each cylinder row. In an internal combustion engine in which a common intake manifold is connected to an intake port, the intake manifold has its lower surfaces on both sides respectively resting on a pair of support surfaces formed on the cylinder heads of the pair of cylinder rows so as to be flush with each other. It is composed of an upper half part which is bonded by polymerization, and a lower half part which is bonded to the upper half part with a joining surface flush with the lower surfaces on both sides and whose lower end protrudes into the valley between both cylinder rows,
In order to provide direct communication between the intake passages in the upper half and the corresponding intake ports through the overlapping surfaces of the upper half and the cylinder head, the intake passages are provided on the lower surfaces of both sides of the upper half. an outlet of the cylinder head, and an inlet of an intake port is opened in both support surfaces of the cylinder head, respectively.
Internal combustion engine. 2 The intake manifold is provided with two systems of intake passages having different intake inertia effects, and an on-off valve for opening and closing one of the intake passages, and the on-off valve opens and closes a part of the lower half. 2. An internal combustion engine according to claim 1, wherein the internal combustion engine is arranged in a valve support plate having an upper end face joined to the upper half portion.