JP2017150426A - Intake device of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance intake air charging efficiency and increase the output of an internal combustion engine by smoothly introducing intake air into each branch pipe.SOLUTION: A surge tank 32 has a tank internal space 44. Plural branch pipes 34 are provided on a peripheral wall 3206 at intervals in the extending direction of the tank internal space 44. A swirl flow forming part 46 is provided at one end in the extending direction of the tank internal space 44. The swirl flow forming part 46 forms a swirl flow F in the tank internal space 44 by the intake air introduced to the one end in the extending direction of the tank internal space 44 from a throttle valve 24. The intake air introduced to the swirl flow forming part 46 from the throttle valve 24 forms the swirl flow F at the one end in the extending direction of the tank internal space 44. The swirl flow F moves from the one end to the other end of the tank internal space 44 to reach each branch pipe 34 and is introduced into each intake port from each branch pipe 34.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an intake device for an internal combustion engine.

2. Description of the Related Art Conventionally, an intake device for an internal combustion engine having an intake manifold having a surge tank into which intake air is introduced from a throttle valve and a plurality of branch pipes branched from the surge tank and supplying intake air to the intake port of the internal combustion engine is known. (See Patent Document 1).
The surge tank has a tank internal space sufficient to alleviate intake pulsation and intake interference that may occur in each cylinder.

JP-A-10-18849

However, in the above prior art, the intake air introduced into the tank inner space collides with the inner surface of the surge tank and flows in various directions in the tank inner space, and the intake air flow interferes with each other. There is room for improvement in improving the intake charging efficiency of each cylinder by smoothly guiding the air to each branch pipe.
The present invention has been made in view of the above circumstances, and provides an intake device for an internal combustion engine that is advantageous in increasing intake charge efficiency and engine output by smoothly guiding intake air to each branch pipe. With the goal.

In order to achieve the above object, an invention according to claim 1 is directed to an intake having a surge tank into which intake air is introduced, and a plurality of branch pipes that branch from the surge tank and supply intake air to an intake port of an internal combustion engine. An intake device for an internal combustion engine including a manifold, wherein the surge tank includes a tank inner space extending in a direction in which the plurality of branch pipes are arranged, and the tank inner space is an extension of the tank inner space. It is characterized by including a swirl flow forming portion that forms a swirl flow in the tank internal space by the introduced intake air at one end in the existing direction.
The invention described in claim 2 is characterized in that the tank internal space is formed such that the cross section of the other end in the extending direction of the tank internal space is smaller than the cross section of the one end.
The invention according to claim 3 is characterized in that the space in the tank is formed so that the cross section gradually becomes smaller from the one end to the other end in the extending direction of the tank internal space.
According to a fourth aspect of the present invention, the swirl flow forming section includes an intake air introduction pipe that forms a swirl flow in the tank inner space by guiding the intake air to the one end of the tank inner space. A first end face wall that closes one end in the extending direction of the tank internal space, and a first wall portion and a second wall portion that extend along the extending direction of the tank internal space while facing each other. And an angle formed by the first end wall and the first wall portion when viewed from a direction orthogonal to the extending direction of the tank internal space is the first end wall and the second The intake inlet pipe is provided on the second wall part, and the plurality of branch pipes are provided side by side on the first wall part. And
The invention according to claim 5 further includes an exhaust gas introduction pipe for supplying exhaust gas exhausted from the internal combustion engine to the intake air, and an end portion of the exhaust gas introduction pipe for supplying the exhaust gas is formed in the tank. It is arrange | positioned in the radial direction center part of the said swirl | vortex flow at the end of the extension direction of space.

According to the first aspect of the present invention, the intake air guided to the space in the tank becomes a swirl flow by the swirl flow forming portion, and the intake air that has turned into the swirl flow flows into each branch pipe arranged in the extending direction of the space in the tank. Since it is guided smoothly, the intake charge efficiency of each cylinder can be increased, which is advantageous for increasing the output of the internal combustion engine.
According to the second aspect of the present invention, the flow velocity of the intake air led to each branch pipe is maintained and the flow to the branch pipe is suppressed by suppressing a decrease in the flow speed of the swirl flow created by the swirl flow forming portion. Since the uneven intake air amount is suppressed, the uneven intake charge efficiency of each cylinder can be suppressed while increasing the intake charge efficiency of each cylinder, which is further advantageous in increasing the output of the internal combustion engine.
According to the invention described in claim 3, it is more advantageous to enhance the effect of claim 2.
According to the fourth aspect of the invention, in the tank space, it is possible to suppress the deviation of the intake amount led from the intake introduction pipe to each branch pipe, that is, the deviation of the intake charge efficiency of each cylinder, and increase the output of the internal combustion engine. This is even more advantageous.
According to the fifth aspect of the present invention, since the end of the exhaust gas introduction pipe is disposed at a location where the pressure formed by the swirling flow is further reduced, introduction of exhaust gas into the intake air can be promoted, This is advantageous for reducing nitrogen oxides (NOx) and improving fuel efficiency (thermal efficiency).

It is a schematic block diagram which shows the structure of the intake device of the internal combustion engine which concerns on 1st Embodiment. 1 is a perspective view of an intake device for an internal combustion engine according to a first embodiment. FIG. 3 is a sectional view taken along line AA in FIG. 2. FIG. 3 is a view taken in the direction of arrow B in FIG. 2. It is CC sectional view taken on the line of FIG. It is sectional drawing of the intake device of the internal combustion engine which concerns on 2nd Embodiment. It is a schematic block diagram which shows the structure of the intake device of the internal combustion engine which concerns on 3rd Embodiment.

(First embodiment)
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the engine 10 includes an engine body 12, an intake device 14, an exhaust device 16, and an exhaust gas recirculation device 18.

The engine main body 12 includes a cylinder block 1202 and a cylinder head 1204.
A plurality of cylinders (cylinder chambers) 20 are formed in the cylinder block 1202. In the present embodiment, three cylinders 20 are formed, and a piston is disposed in each cylinder 20.
The cylinder head 1204 is provided with a combustion chamber, an intake port for supplying intake air to the combustion chamber, and an exhaust port for discharging exhaust gas from the combustion chamber, not shown, corresponding to each cylinder 20. .
Accordingly, three combustion chambers, three intake ports, and three exhaust ports are provided.

The intake device 14 includes an intake pipe 22, a throttle valve 24, an intake manifold 28, and an exhaust gas introduction pipe 30.
The upstream end of the intake pipe 22 is connected to an air cleaner (not shown), and the throttle valve 24 is connected to the downstream end of the intake pipe 22.
The throttle valve 24 adjusts the amount of intake air into the engine 10, and the opening degree of the throttle valve 24 is adjusted by the engine ECU 42.

The intake manifold 28 includes a surge tank 32 and a plurality of branch pipes 34.
The surge tank 32 controls intake pulsation and intake interference that can occur in each cylinder 20.
The plurality of branch pipes 34 are branched from the surge tank 32 and connected to the intake ports. In FIG. 3, reference numeral 3402 indicates the opening of the branch pipe 34 that opens into the surge tank 32.
In the present embodiment, the intake passage that guides the intake air to the combustion chamber includes the intake pipe 22, the throttle valve 24, the intake manifold 28, and the intake port.
The exhaust device 16 includes an exhaust manifold 36 connected to the exhaust port and an exhaust pipe 38 connected to the exhaust manifold 36.
The exhaust gas recirculation device 18 recirculates the exhaust gas taken out from the exhaust pipe 38 to the surge tank 32.
The exhaust gas recirculation device 18 includes an exhaust gas introduction pipe 30 and an exhaust gas valve 40.
The exhaust gas introduction pipe 30 connects the exhaust pipe 38 and the surge tank 32 and recirculates the exhaust gas.
The exhaust gas valve 40 is provided in the exhaust gas introduction pipe 30 to adjust the recirculation amount of the exhaust gas, and the opening degree of the exhaust gas valve 40 is adjusted by the engine ECU 42.

Next, the surge tank 32 will be described in detail.
As shown in FIGS. 3 and 4, the surge tank 32 includes a tank internal space 44.
The surge tank 32 includes a circular first end wall 3202 that closes one end in the extending direction of the tank inner space 44, and a circular second end wall 3204 that closes the other end in the extending direction of the tank inner space 44. And a peripheral wall 3206 that connects the first end face wall 3202 and the second end face wall 3204.
In FIG. 3, reference numeral 4402 denotes the central axis of the tank internal space 44.
The plurality of branch pipes 34 are provided on the peripheral wall 3206 at intervals in the extending direction of the tank internal space 44.
As shown in FIG. 5, the plurality of branch pipes 34 are connected in a tangential direction of a swirling flow F described later in the tank inner space 44, in other words, connected in a tangential direction of the peripheral wall 3206.
The tank internal space 44 is formed such that the cross section of the other end in the extending direction of the tank internal space 44 is smaller than the cross section of the one end. In the present embodiment, as shown in FIG. 3, the tank inner space 44 is formed so that its cross section gradually decreases from one end to the other end in the extending direction of the tank inner space 44, in other words, The tank internal space 44 has a truncated cone shape in which the radius gradually decreases from one end to the other end.

As shown in FIGS. 3 and 4, a swirl flow forming portion 46 is provided at one end in the extending direction of the tank inner space 44.
The swirl flow forming unit 46 forms a swirl flow F in the tank inner space 44 by intake air introduced from the throttle valve 24 at one end in the extending direction of the tank inner space 44.
In the present embodiment, the swirl flow forming portion 46 has a first end face wall 3202, a part 3210 of the peripheral wall 3206 near the first end face wall 3202, and an intake air projecting in a tangential direction of the part 3210 of the peripheral wall 3206. And an introduction pipe 48.
A front end 48A of the intake air introduction pipe 48 is connected to the downstream end 24A of the throttle valve 24. In FIG. 3, reference numeral 4802 denotes an opening of the intake air introduction pipe 48 formed in the peripheral wall 3206.
Therefore, the intake air introduced from the throttle valve 24 into the swirl flow forming portion 46 becomes a swirl flow F at one end in the extending direction of the tank inner space 44 by the intake air introduction pipe 48 and the portion 3210 of the peripheral wall 3206. While moving from one end of the tank internal space 44 toward the other end, each branch pipe 34 is reached, and is introduced from each branch pipe 34 to each intake port.

  The exhaust gas introduction pipe 30 is disposed so as to penetrate the first end wall 3202, and the end portion 3002 of the exhaust gas introduction pipe 30 is one end in the extending direction of the tank internal space 44 and the center of the cross section of the tank internal space 44. Is arranged. That is, the end portion 3002 of the exhaust gas introduction pipe 30 is disposed at the central portion in the radial direction of the swirling flow F formed by the swirling flow forming portion 46.

Next, the function and effect will be described.
When the engine 10 is operated with the throttle valve 24 opened at a predetermined opening by the engine ECU 42, the intake air is swirled from the intake pipe 22 through the throttle valve 24 as shown in FIGS. It is introduced into the intake air introduction pipe 48 of the forming portion 46.
The intake air introduced into the intake air introduction pipe 48 is smoothly guided along the inner surface of the peripheral wall 3206 at one end of the tank inner space 44 and becomes a swirl flow F flowing along the inner surface of the peripheral wall 3206.
The intake air that has become the swirling flow F flows from one end of the tank inner space 44 toward the other end along the extending direction of the tank inner space 44 while swirling, and swirls as shown in FIGS. The intake air that has become the flow F reaches each branch pipe 34 and is smoothly guided to the intake port via each branch pipe 34.
Furthermore, in the present embodiment, the tank inner space 44 is formed so that the cross section gradually decreases from one end to the other end in the extending direction of the tank inner space 44. By turning along the space 44, the outer diameter of the swirling flow F gradually decreases as it approaches the other end of the in-tank space 44.
When the outer diameter of the swirling flow F does not change and is constant, the energy of the swirling flow F decreases as the swirling flow F approaches the other end of the tank inner space 44, and therefore approaches the other end of the tank inner space 44. As the speed of the swirl flow F decreases.
On the other hand, in the present embodiment, the cross section gradually decreases from one end to the other end in the extending direction of the tank inner space 44, and the outer diameter of the swirling flow F is gradually reduced. F reaches each branch pipe 34 in a state where a decrease in the flow velocity of the swirl flow F is suppressed, and is guided to the intake port via each branch pipe 34.

On the other hand, when the exhaust gas valve 40 is opened at a predetermined opening by the engine ECU 42, the exhaust gas passes through the exhaust gas introduction pipe 30 and the exhaust gas valve 40 from the exhaust pipe 38 and ends 3002 of the exhaust gas introduction pipe 30. To be supplied.
The end portion of the exhaust gas introduction pipe 30 is located near the center of the cross section of the tank inner space 44 at one end in the extending direction of the tank inner space 44, and thus is positioned at the radial center of the swirling flow F. .
The swirling flow F decreases in pressure as it goes from the outside in the radial direction to the inside.
Therefore, the end portion 3002 of the exhaust gas introduction pipe 30 is located at a location where the pressure in the tank internal space 44 is further reduced.
As a result, the exhaust gas supplied to the exhaust gas introduction pipe 30 is guided to a location where the pressure in the tank inner space 44 is further reduced, and the introduction of the exhaust gas into the tank inner space 44 is promoted.

For example, the pressure in the tank inner space 44 near the end 3002 of the exhaust gas introduction pipe 30 even when the engine 10 is under a low load, that is, when the throttle valve 24 is in a small opening and the intake amount is small. As a result, the introduction of exhaust gas into the intake air is promoted.
Further, when the engine 10 is at a high load, that is, when the throttle valve 24 is fully open or close to full open, and the intake air amount is large, the flow velocity of the swirling flow F becomes faster. The pressure in the tank inner space 44 near the end portion 3002 of the pipe 30 is further reduced, and the introduction of exhaust gas into the intake air is further promoted.

The exhaust gas supplied from the end portion 3002 of the exhaust gas introduction pipe 30 to the central portion of the swirling flow F is mixed with the intake air that has turned into the swirling flow F, passes through the tank inner space 44 along the extending direction of the tank inner space 44. The tank inner space 44 moves from one end to the other end.
The intake air and exhaust gas moving in the tank inner space 44 are further mixed by maintaining the swirl flow F in the tank inner space 44 and introduced from the tank inner space 44 to the intake ports via the branch pipes 34. .

  According to the present embodiment, the intake air guided to the tank inner space 44 becomes the swirl flow F by the swirl flow forming unit 46, and the intake air that has turned the swirl flow F is arranged in the extending direction of the tank inner space 44. Since the air is smoothly guided to the branch pipe 34, the intake charging efficiency of each cylinder 20 can be increased, which is advantageous in increasing the output of the engine 10.

Further, according to the present embodiment, the tank inner space 44 is formed so that the cross section gradually decreases from one end to the other end in the extending direction of the tank inner space 44. Reduction can be suppressed.
Therefore, the flow rate of the intake air guided to each branch pipe 34 is maintained and the bias of the intake air amount guided to each branch pipe 34 is suppressed, so that the intake charge efficiency of each cylinder 20 is increased and each cylinder 20 is improved. The bias of the intake charging efficiency can be suppressed, which is further advantageous in increasing the output of the engine 10.

  Further, according to the present embodiment, since the swirl flow F is formed in the swirl flow forming unit 46 and the end portion 3002 of the exhaust gas introduction pipe 30 is disposed at a location where the pressure of the swirl flow forming unit 46 is further reduced, The introduction of exhaust gas into the intake air can be promoted, which is advantageous in reducing nitrogen oxide (NOx) in the exhaust gas and improving fuel consumption (thermal efficiency).

(Second Embodiment)
Next, a second embodiment will be described with reference to FIG.
In the following embodiments, the same portions and members as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted or simplified, and different portions are mainly described.
The peripheral wall 3206 of the surge tank 32 has a first wall portion 3206A and a second wall portion 3206B that extend along the extending direction of the tank internal space 44 while facing each other.
A cross section of the tank inner space 44 cut by a plane orthogonal to the central axis 4402 is circular, and the tank inner space 44 has a frustoconical shape.
The intake introduction pipe 48 is provided so as to open to the second wall portion 3206B.
The plurality of branch pipes 34 are provided side by side on the first wall portion 3206A.
The plurality of branch pipes 34 have the same length.
In the figure, reference numeral 50 denotes an intake port to which each branch pipe 34 is connected.

When viewed from the direction orthogonal to the extending direction of the tank inner space 44, the angle θ1 formed between the first end wall 3202 and the first wall 3206A is determined by the first end wall 3202 and the second wall 3206B. It is formed smaller than the angle θ2 formed by
According to the present embodiment, the difference in distance from the opening 4802 of the intake introduction pipe 48 to the opening 3402 of each branch pipe 34 is reduced.
Specifically, the distance from the opening 4802 of the intake pipe 48 to the opening 3402 of the first branch pipe 34A, the distance from the opening 4802 of the intake pipe 48 to the opening 3402 of the second branch pipe 34B, and the intake pipe 48 The difference from the distance from the opening 4802 to the opening 3402 of the third branch pipe 34C is reduced.

By the way, the longer the length of the path through which the intake air passes through the tank inner space 44 as the swirl flow F, the longer it takes for the intake air to reach the opening 3402 of the intake pipe 48 from the opening 4802 of the intake pipe 48. .
For this reason, if the length of the path through which the intake air guided to each branch pipe 34 passes is large, the bias of the intake amount guided to the cylinder 20 increases, and the intake charge efficiency and the exhaust gas introduction amount of each cylinder 20 are uneven. There is a concern that will become larger.

In the present embodiment, the difference in distance from the opening 4802 of the intake pipe 48 to the opening 3402 of each branch pipe 34 is reduced, so that the opening 4802 of the intake pipe 48 reaches the opening 3402 of each branch pipe 34. The difference in the length of the path through which the intake air passes as the swirling flow F is reduced.
Accordingly, in the tank inner space 44, the bias of the intake air amount led from the opening 4802 of the intake pipe 48 to the opening 3402 of each branch pipe 34, that is, the bias of the intake air amount guided to each cylinder 20 is suppressed. The bias in the intake charge efficiency of the cylinder 20 and the deviation of the exhaust gas introduction amount can be suppressed, which is further advantageous in increasing the output of the engine 10.

(Third embodiment)
Next, a third embodiment will be described with reference to FIG.
In the third embodiment, a swirl flow forming portion 66 is provided at one end in the extending direction of the tank internal space 64 of the surge tank 62, as in the first and second embodiments.
In the tank internal space 64, the swirl flow forming portion 66 is formed with a circular section having a uniform radius, and the remaining tank internal space 64 excluding the swirl flow forming portion 66 has a radius larger than that of the circular cross section of the swirl flow forming portion 66. It is formed with a circular section with a small uniform radius.
Therefore, the tank internal space 64 is formed such that the cross section of the other end in the extending direction of the tank internal space 64 is smaller than the cross section of the one end.
Similarly to the first and second embodiments, the end portion 3002 of the exhaust gas introduction pipe 30 is disposed at the central portion in the radial direction of the swirling flow F formed by the swirling flow forming portion 66.

The intake air introduced into the intake air introduction pipe 48 is smoothly guided in the swirling flow forming portion 66 along the inner surface of the peripheral wall of the swirling flow forming portion 66 and becomes a swirling flow F flowing along the inner surface of the peripheral wall.
The intake air that has become the swirl flow F reaches the remaining tank internal space 64 excluding the swirl flow formation portion 66 from the swirl flow formation portion 66, and the remaining tank internal space 64 has a smaller cross-sectional area than the swirl flow formation portion 66. For this reason, the swirl flow F reaches each branch pipe 34 in a state where the flow velocity of the swirl flow F in the swirl flow forming unit 66 is suppressed, and is guided to the intake port via each branch pipe 34.
Therefore, the flow rate of the intake air guided to each branch pipe 34 is maintained, and the deviation of the intake air amount guided to each branch pipe 34 is suppressed, so that the intake charge efficiency of each cylinder 20 is increased and each cylinder 20 is improved. The bias of the intake charging efficiency can be suppressed, which is advantageous in increasing the output of the engine 10.
Also in the third embodiment, since the swirl flow F is formed by the swirl flow forming unit 66 and the end portion 3002 of the exhaust gas introduction pipe 30 is disposed at a location where the pressure of the swirl flow forming unit 66 is further reduced. The introduction of exhaust gas into the intake air can be promoted, which is advantageous in reducing nitrogen oxide (NOx) in the exhaust gas and improving fuel consumption (thermal efficiency).

10 Engine (Internal combustion engine)
14 Intake device 28 Intake manifold 30 Exhaust gas introduction pipes 32, 62 Surge tank 34 (34A, 34B, 34C) Branch pipes 44, 64 Tank internal space 3202 First end face wall 3204 Second end face wall 3206 Peripheral wall 3206A First Wall portion 3206B Second wall portions 46, 66 Swirl flow forming portion 48 Intake intake pipe F Swirling flow

Claims (5)

An intake device for an internal combustion engine comprising an intake manifold having a surge tank into which intake air is introduced and a plurality of branch pipes branched from the surge tank and supplying intake air to the intake port of the internal combustion engine,
The surge tank includes a tank internal space extending in a direction in which the plurality of branch pipes are arranged,
The tank internal space is configured to include a swirl flow forming portion that forms a swirl flow in the tank internal space by the intake air introduced at one end in the extending direction of the tank internal space.
An intake device for an internal combustion engine characterized by the above. The tank internal space is formed such that a cross section of the other end in the extending direction of the tank internal space is smaller than a cross section of the one end.
The intake device for an internal combustion engine according to claim 1. The tank internal space is formed such that the cross section gradually decreases from the one end to the other end in the extending direction of the tank internal space.
3. An intake device for an internal combustion engine according to claim 1, wherein the intake device is an internal combustion engine. The swirl flow forming unit is configured to include an intake air introduction pipe that forms a swirl flow in the tank internal space by guiding the intake air to the one end of the tank internal space.
The surge tank includes a first end wall that closes one end in the extending direction of the tank inner space, a first wall portion that extends along the extending direction of the tank inner space while facing each other, and a first wall portion. Two wall portions,
When viewed from a direction orthogonal to the extending direction of the space in the tank, an angle formed between the first end wall and the first wall is an angle between the first end wall and the second wall. Smaller than the angle to make,
The intake pipe is provided on the second wall;
The plurality of branch pipes are provided side by side on the first wall.
The intake device for an internal combustion engine according to any one of claims 1 to 3, wherein An exhaust gas introduction pipe for supplying exhaust gas exhausted from the internal combustion engine to the intake air;
An end portion of the exhaust gas introduction pipe that supplies the exhaust gas is disposed at a radial center portion of the swirling flow at one end in the extending direction of the space in the tank.
The intake device for an internal combustion engine according to any one of claims 1 to 4, wherein the intake device is an internal combustion engine.

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