JP4075037B2 - Engine intake system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an intake device for an engine in which an intake passage is formed so as to surround a surge tank.
[0002]
[Prior art]
Conventionally, an intake device of an engine is provided with a surge tank and a branch passage branched from the surge tank and connected to an intake port of each cylinder, and an inertia effect and a resonance effect due to pressure pulsation generated in each branch passage. Various techniques for increasing the intake charging efficiency by using the dynamic supercharging effect such as the above are employed. In this dynamic supercharging effect, the inertial effect is that when the negative pressure wave generated in each branch passage bounces back in the surge tank, the connection part between the surge tank and each branch passage becomes almost free end and the negative pressure wave becomes positive pressure wave. By reversing and applying this positive pressure wave to the intake valve immediately before closing, the intake charge efficiency is increased. The engine speed range in which the intake air charging efficiency is increased by this inertial effect depends on the length of the branch passage, and it is effective to make it longer in the low speed range and shorter in the high speed range.
[0003]
By the way, in order to increase the intake charge efficiency in both the high speed operation state and the low speed operation state with respect to the engine due to the inertia effect, a low speed passage branched from the surge tank and communicating with each cylinder of the engine, and a branch from the surge tank A technique has been put into practical use in which two branch passages, which are a high-speed passage communicating with the low-speed passage in the middle so as to bypass the low-speed passage, can be varied by a rotary valve having a small flow resistance of intake air.
[0004]
For example, as shown in FIGS. 26 and 27, in the intake device described in Japanese Patent Laid-Open No. 10-89171, the two openings 101 and 102 for high speed and low speed are mutually separated by a predetermined distance in the circumferential direction of the surge tank 100. These two openings 101 and 102 can be opened / closed by a rotary valve 103 which is formed so as to be separated from the surge tank 100 so as to be rotatable.
[0005]
In the low-speed operation state, as indicated by the solid line arrow in FIG. 27, the intake air passes through the low-speed intake passage 104 and the common intake passage 105 from the surge tank 103 through the low-speed opening 102 and substantially circulates the outer periphery of the surge tank 100. After that, it is supplied to the intake port. On the other hand, in the high speed operation state, as indicated by the dotted arrow in FIG. 27, the intake air is supplied from the surge tank 100 through the high speed opening 101 to the intake port through the common intake passage 105.
[0006]
Japanese Patent No. 2824294 discloses a configuration in which a low-speed passage is bundled and connected to a surge tank, a high-speed passage is bundled and connected to a surge tank, and branched to each low-speed passage.
[0007]
[Problems to be solved by the invention]
In the intake device of the above publication, the high speed opening 101 and the low speed opening 102 are formed apart from each other on the circumference of the surge tank 100. When switching between the low speed operation state and the high speed operation state, the rotary opening 101 Although the valve 103 is in a transient state where the valve 103 is switched over the two openings 101 and 102, the opening area is temporarily reduced at this time, so that the intake air flows from the surge tank 100 to the low-speed intake passage 104 or the common intake passage 105. The resistance at the time of outflow (hereinafter referred to as intake / outflow resistance) increases and the intake charging efficiency decreases.
[0008]
Further, in order to obtain a sufficient inertia effect in the low-speed operation state, the low-speed intake passage 104 needs to have a predetermined length or more. For this reason, the low-speed intake passage 104 is formed to have a passage length that substantially circulates around the outer peripheral portion of the surge tank 100, and the length of the surge tank 100 in the cylinder row direction increases, so that the intake port from the throttle valve extends over a plurality of cylinders. It is difficult to reduce the difference in the path lengths until the cylinders vary, and the dynamic supercharging effect varies from cylinder to cylinder.
[0009]
The present invention has been made in view of the above problems, and an object of the present invention is to provide an engine intake device capable of forming an arrangement space for an auxiliary machine or the like while ensuring an intake passage length and ensuring intake charge efficiency in a low-speed operation state. That is.
[0010]
[Means for Solving the Problems]
In order to solve the above-described problems and achieve the object, an intake device for an engine according to the present invention includes a branch passage that branches from the collective passage and communicates with each cylinder of the engine, and extends from the collective passage. In an intake system for an engine that is bent downward in the collecting passage, is curved to surround the collecting passage from the side opposite to the engine unit of the collecting passage, and is connected to the intake port of the engine. The connecting position of the branch passage with respect to the collective passage is set at an upper portion of the collective passage, and each of the branch passages is curved from the upper portion of the collective passage to the engine unit side and extends downward. Of the branch passages, the connection positions of the branch passages located at both ends in the cylinder row direction with respect to the collective passage are portions farther from the engine unit than the connection positions of the branch passages located in the center of the cylinder row direction with respect to the collective passage. Below the collecting passage, the branch passages are arranged in the cylinder row direction, and the collecting passages of the branch passages located at both ends in the cylinder row direction Of the branch passage below The collective passage of the branch passage whose lower end position is located at the center in the cylinder row direction when viewed from one side in the cylinder row direction Of the branch passage below It is arranged at a position higher than the lower end position.
[0011]
Preferably, the branch passages located at both ends in the cylinder row direction branch through a common passage that overlaps with the branch passage located in the cylinder row direction center extending from the collective passage.
[0012]
Preferably, the branch passages positioned at both ends in the cylinder row direction are branched from the collective passage, then curved at a position higher than the branch passage located in the center of the cylinder row direction, and located in the center of the cylinder row direction. The branch passage extends to both ends in the cylinder row direction and extends below the collecting passage.
[0013]
Preferably, a plurality of branch passages are provided at the center in the cylinder row direction, and extend from the collective passage to each cylinder through the common passage.
[0014]
Preferably, the branch passages located at both ends of the cylinder row direction and the branch passages located at the center of the cylinder row direction are linearly arranged in the cylinder row direction on the engine unit side of the collective passage.
[0015]
Preferably, at least an upstream end opening of the branch passage located at both ends in the cylinder row direction and an upstream end opening of the branch passage located at the center in the cylinder row direction are inclined in the intake flow direction of the collective passage. ing.
[0016]
Preferably, all the upstream end openings of the branch passage are inclined in the intake flow direction of the collecting passage.
[0017]
Also preferably, the above each Branch passage Is The gathering passage Curved downward from the collective passage while extending obliquely upward from the openings of the branch passages connected to the engine unit toward the engine unit. is doing.
[0018]
【The invention's effect】
As described above, according to the first aspect of the present invention, of the branch passages, the connecting positions of the branch passages located at both ends in the cylinder row direction are connected to the collective passage of the branch passage located in the center in the cylinder row direction. The branch passages are located farther from the engine unit than the connection position, and the branch passages are arranged in the cylinder row direction below the collective passages, and are located at both ends of the cylinder row direction. Of the branch passage below The collective passage of the branch passage whose lower end position is located in the center of the cylinder row direction when viewed from one side of the cylinder row direction Of the branch passage below By disposing at a position higher than the lower end position, it is possible to form an arrangement space for an auxiliary machine or the like while ensuring the intake passage length and ensuring the intake charge efficiency in the low-speed operation state.
[0019]
According to the invention of claim 2, the branch passages located at both ends of the cylinder row direction branch from the throttle valve by branching through the common passage overlapping the branch passage located at the center of the cylinder row direction extending from the collecting passage. The path length to the intake path can be made substantially equal, and unpleasant noise caused by the difference in pressure pulsation frequency due to the difference in path length can be suppressed.
[0020]
According to the invention of claim 3, the branch passages located at both ends in the cylinder row direction are branched from the collecting passage, and then curved at a position higher than the branch passage located at the center in the cylinder row direction, and located at the center in the cylinder row direction. By extending to both ends of the branch passage in the cylinder row direction and extending below the collecting passage, the intake passage length can be made substantially equal to ensure the intake charging efficiency in the low speed operation state.
[0021]
According to the fourth aspect of the present invention, a plurality of branch passages located in the center of the cylinder row direction are provided and extend from the collective passage to each cylinder via the common passage, so that the intake passage length is made substantially equal and the low speed operation is performed. The intake charge efficiency in the state can be secured.
[0022]
According to the invention of claim 5, the branch passages located at both ends in the cylinder row direction and the branch passages located in the center of the cylinder row direction are arranged in a straight line in the cylinder row direction on the engine unit side of the collective passage. The size of the intake device can be reduced, and a space for arranging the intake device can be secured between the radiator unit and the engine unit, which are arranged in front of the engine room, and the engine unit in the longitudinal direction of the vehicle body.
[0023]
According to the invention of claim 6, at least the upstream end opening of the branch passage located at both ends in the cylinder row direction and the upstream end opening of the branch passage located at the center in the cylinder row direction are inclined in the intake flow direction of the collective passage. Thus, the intake flow resistance from the collecting passage to the branch passage can be reduced.
[0024]
According to the invention of claim 7, since all the upstream end openings of the branch passage are inclined in the intake flow direction of the collecting passage, the intake flow resistance from the collecting passage to the branch passage can be reduced.
[0025]
According to the invention of claim 8, each Branch passage Is Meeting passage Curved downward from the collective passage while extending obliquely upward from the openings of the respective branch passages connected to the engine unit toward the engine unit. As a result, the intake air flows along the inner wall of the passage, and the secondary flow that becomes a spiral component is suppressed by the reflection of the intake air on the inner wall of the passage, thereby reducing the intake pressure loss and the average flow coefficient (Cf). Can be increased.
[0026]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
[0027]
The embodiment described below is an example applied to an intake device of an in-line four-cylinder engine for automobiles as means for realizing the present invention. However, the present invention does not depart from the spirit thereof, for example, the number of cylinders. Is not limited to four cylinders, and can be applied to a modified or modified embodiment of the following embodiment so that it can be mounted on other engine types such as V6, V8, and horizontally opposed.
[First Embodiment]
First, an engine intake device according to a first embodiment of the present invention will be described.
[0028]
In the following description, in the front view of the engine of FIG. 1, the vertical direction of the paper is the vertical direction of the vehicle body, the horizontal direction is the vehicle width direction (cylinder row direction), and the front and back direction is the vehicle body longitudinal direction. In the plan view of the engine, the front and back direction of the paper is the vertical direction of the vehicle body, the left-right direction is the vehicle width direction (cylinder row direction), and the vertical direction is the front-rear direction of the vehicle body. Although it is an example that is horizontally placed, the present invention is not limited to this, and it goes without saying that it can also be applied to a vertically placed vehicle in the longitudinal direction.
[0029]
FIG. 1 is a front view of an intake device for an engine according to the first embodiment of the present invention, FIG. 2 is a plan view of the intake device for the engine according to the first embodiment of the present invention, and FIG. 3 is a first embodiment according to the present invention. FIG. 4 is a left side view of the engine intake device of the first embodiment according to the present invention, and shows an engine unit of an in-line four-cylinder engine 1 (hereinafter referred to as engine 1). 2 has a cylinder block 2a and a cylinder head 2b. In the cylinder block 2a, four first to fourth cylinders 3A to 3D arranged in series from the right to the left in the drawing are formed. The cylinder head 2b is formed with a top surface portion 3a in which upper ends of the cylinders 3A to 3D are defined and two intake ports 8 and two exhaust ports 9 communicating with the cylinders 3A to 3D are formed. . Each intake port 8 is provided with an intake valve 5 that opens and closes a port opening 8a that communicates with each of the cylinders 3A to 3D, and a valve guide that operates coaxially with a tangent line that contacts the axis of the intake port 8 at the port opening 8a. Guided at 5a. As with each intake port 8, each exhaust port 9 is provided with an exhaust valve 6 that opens and closes a port opening 9a communicating with each of the cylinders 3A to 3D, and a tangent line that contacts the axis of the exhaust port 9 at the port opening 9a. Is guided by a valve guide 6a so as to operate coaxially.
[0030]
In each of the cylinders 3A to 3D, a combustion chamber is formed by the top surface portion 3a, the piston 4, the two intake valves 5, and the two exhaust valves 6. The intake port 8 has one upstream portion and branches toward the two intake valves 5 on the way. The engine unit 2 is provided with an intake device 7 for introducing intake air into each of the cylinders 3A to 3D on one side in front of the front-rear direction of the vehicle body. The intake air introduced from the intake device 7 is By opening the intake valve 5 through the intake port 8, the cylinders 3A to 3D are filled at a predetermined timing (for example, the order of 3A → 3C → 3D → 3B).
<Intake device>
Next, the intake device 7 will be described.
[0031]
As shown in FIGS. 1 to 4, the intake device 7 includes an intake pipe 23, a surge tank (collection passage) 10, and intake ports 8 of four cylinders 3 </ b> A to 3 </ b> D branched from the outer peripheral portion of the surge tank 10. And four first branch passages 11 to 14 respectively connected to each other, and in the middle of the first branch passages 11 to 14 so as to branch from the outer peripheral portion of the surge tank 10 and short-circuit the first branch passages 11 to 14. The communication state between the second branch passages 15 to 18 communicating with the surge tank 10 and the first branch passages 11 to 14 or the second branch passages 15 to 18 can be selectively changed according to the operating state of the engine. Rotary valve (variable intake mechanism) 20. The surge tank 10 and the first and second branch passages 11 to 18 are integrally formed of a material such as synthetic resin.
[0032]
The surge tank 10 is formed in a hollow cylindrical shape whose axis extends horizontally in the left-right direction, and is disposed near one side of the front-rear direction of the vehicle body of the engine unit 2. An intake pipe 23 is connected to the right end of the surge tank 10. A throttle body 24 is provided in the downstream portion of the intake pipe 23. This throttle body 24 has a built-in throttle valve 24a, and the amount of intake air flowing into the surge tank 10 changes in accordance with the depression of the accelerator pedal or the electrically driven actuator operation. Is adjusted. The length of the surge tank 10 in the left-right direction is shorter than the distance between the two intake ports 8 corresponding to the cylinders 3A, 3D at the left and right ends.
[0033]
The first branch passages 11-14 extend obliquely upward from the first upstream end openings 11a-14a connected to the outer peripheral portion of the surge tank 10 to the engine unit 2 side from the first upstream end openings 11a-14a. The first pipe portions 11b to 14b that are curved downward and extend linearly below the surge tank 10 and the second pipes 11b to 14b that extend linearly above the surge tank 10 while curving to the anti-engine unit 2 side below the surge tank 10. Pipe portions 11c to 14c, and third pipe portions 11d to 14d that are curved and extend to the engine unit 2 side above the surge tank 10 and are connected to an intake port 8 that opens to the side surface of the engine 1 via a mounting flange 25. Have
[0034]
Further, the first pipe portions 11b to 14b that are curved from the upper side of the surge tank 10 and extend downward in the first branch passages 11 to 14 are formed so as to be arranged in a substantially planar shape in the cylinder row direction on the engine unit 2 side. .
[0035]
The second pipe portions 11c to 14c extending upward from below the surge tank 10 in the first branch passages 11 to 14 are arranged in a substantially planar shape in the cylinder row direction on the side opposite to the engine unit 2 and are located at both ends in the cylinder row direction. The lower end position P1 of the pipe portions 11c and 14c is arranged at a position higher than the lower end position P2 of the second pipe portions 12c and 13c located at the center in the cylinder row direction when viewed from one side in the cylinder row direction.
[0036]
The second branch passages 15 to 18 extend slightly from the second upstream end openings 15 a to 18 a connected to the outer peripheral portion of the surge tank 10 while curving obliquely upward in a direction far from the engine unit 2. The second pipe portions 11c to 14c of -14 are joined in the middle of the straight portion.
[0037]
The first branch passages 11 to 14 are arranged so as to surround most of the outer periphery of the surge tank 10 (about 4/5), and merge with the second branch passages 15 to 18 on the side opposite to the engine unit 2. The pipe portions 11c to 14c are linearly continuous from the lower side of the surge tank 10 to the upper side.
[0038]
The first branch passages 12 and 13 corresponding to the two central cylinders 3B and 3C are arranged at the left and right cylinders 3A so that the passage lengths from the surge tank 10 to the intake ports 8 of the four cylinders 3A to 3D are equal. , 3D and extending downward from the first branch passages 11 and 14 so as to bend upward and surround most of the outer periphery of the surge tank 10.
[0039]
Each of the first upstream end openings 11 a to 14 a is formed near the top of the outer peripheral portion of the surge tank 10. Of these four first upstream end openings 11a to 14a, the two first upstream end openings 11a and 12a corresponding to the two right cylinders 3A and 3B are the first corresponding to the second cylinder 3B from the right. Two upstream end openings 16a and the outer peripheral portion of the surge tank 10 are formed on substantially the same circumference, while the two first upstream end opening portions 13a and 14a corresponding to the two left cylinders 3C and 3D are The second upstream end opening 17a corresponding to the second cylinder 3C from the left and the outer peripheral portion of the surge tank 10 are formed on substantially the same circumference.
[0040]
FIG. 5 is a cross-sectional view taken along line II of the engine intake device of FIG. 1, and the center line of the two first upstream end openings 11 a and 12 a on the right side branches off from one point on the outer periphery of the surge tank 10. The two first upstream end openings 11a and 12a are formed so as to partially overlap in the substantially same circumferential direction. The two first upstream end openings 13a and 14a on the left are also formed in the same manner as on the right. That is, the four first upstream end openings 11a to 14a are formed close to each other in the vicinity of the central portion in the left-right direction of the surge tank 10, and from the throttle valve 24a to the four first upstream end openings 11a to 14a. The passage lengths are substantially equal.
[0041]
The second upstream end openings 15 a to 18 a of the second branch passages 15 to 18 are arranged side by side in the cylinder row direction with respect to the outer peripheral portion of the surge tank 10.
[0042]
The four second upstream end openings 15a to 18a are arranged close to each other in the left-right direction so that the difference in passage length from the throttle valve 24a to the four second upstream end openings 15a to 18a is reduced. As described above, the length of the surge tank 10 in the left-right direction is shorter than the distance between the two intake ports 8 corresponding to the cylinders 3 at the left and right ends, so the four second upstream end openings 15a-18a from the throttle valve 24a. The difference in the length of the passage is also small.
[0043]
In the above-described configuration, the first branch passages 11 to 14 are set to the intake pipe length that synchronizes with the intake characteristics in the low / medium rotation region of the engine, and the first branch passage short-circuited by the second branch passages 15 to 18 The intake air length is set to be synchronized with the inertial characteristic of the intake air in the maximum rotation range.
[0044]
FIG. 10 is a development view of the rotary valve, and the length L2 between both end portions 15a and 18a in the cylinder row direction in the second upstream end openings 15a to 18a opens to one side of the engine unit 2 to form a cylinder row. The intake port 8 arranged side by side in the direction is set to be shorter than the length L3 between both ends in the cylinder row direction.
[0045]
Further, the length L1 between both end portions 11a, 14a and 12a, 13a in the cylinder row direction in the first upstream end openings 11a to 14a is equal to both end portions 15a in the cylinder row direction in the second upstream end openings 15a to 18a. It is set shorter than the length L2 between 18a.
[0046]
Also, the first upstream end openings 11a, 12a and 13a, 14a formed so as to partially overlap each other are substantially the same as the second upstream end openings 16a, 17a located in the middle in the cylinder row direction. It is arranged on the same circumference.
<Variable intake mechanism>
As shown in FIG. 5, first upstream end openings 11 a to 14 a and second upstream end openings 15 a to 18 a are connected to the outer peripheral portion of the surge tank 10 so as to communicate with the internal space 22 of the surge tank 10. Each of the four openings 10a and 10b is formed. In addition, an inner peripheral portion of the surge tank 10 is disposed inside the surge tank 10 so as to selectively open and close one of the first upstream end openings 11a to 14a and the second upstream end openings 15a to 18a that overlap each other. A rotary valve 20 that is rotatable around the axis 10c is mounted.
[0047]
FIG. 6 shows a perspective view of the rotary valve. The rotary valve 20 made of synthetic resin is formed by integrating a hollow cylindrical outer wall portion 20 a extending over the entire length in the left-right direction and an end wall portion 20 b that closes the left end of the surge tank 10. Formed. As the rotary valve 20 rotates, the four openings 20d formed in the direction of the axis 10c in the outer wall 20a communicate with the openings 10a and 10b formed in the outer peripheral portion of the surge tank 10, so that the first upstream Any one of the end openings 11a to 14a and the second upstream end openings 15a to 18a is selectively opened and closed.
[0048]
The four openings 20d are formed to have a width in the cylinder row direction and a length in the radial direction larger than the opening area of the first upstream end openings 11a, 12a and 13a, 14a formed by overlapping each other. The first upstream end opening portion 12a (13a) and the second upstream end opening portion 16a (17a) formed on the same circumference have a radial length larger than the distance between them, and the engine speed described later is low. The first upstream end openings 11a to 14a and the second upstream end openings 15a to 18a form a transient state in which both the first upstream end openings 11a to 14a and the second upstream end openings 15a to 18a are partially opened when the operation state is between the high-speed operation state and the high-speed operation state .
[0049]
A pivot shaft 20c is protruded at the center of the end wall 20b, and the pivot shaft 20c is rotatably supported.
[0050]
The structure of the rotary valve 20 is not limited to the structure of the above embodiment, and various structures can be adopted.
[0051]
As shown in FIGS. 1 and 2, a diaphragm type actuator 21 that rotationally drives a rotary valve 20 is disposed on the left side of the surge tank 10, and an output portion of the actuator 21 is connected to a pivot shaft 20c. ing. The actuator 21 has a general structure for driving the output portion by applying a negative pressure of the intake system introduced from the intake pipe through the negative pressure introduction pipe to the diaphragm.
[0052]
As shown in FIG. 7, in an operating state where the engine speed is low, the opening 20d of the rotary valve 20 is located at the first upstream end openings 11a to 14a and communicates with the internal space 22 of the surge tank 10. At the same time, the second upstream end openings 15a to 18a are closed.
[0053]
On the other hand, as shown in FIG. 8, when the engine speed is in the high-speed operation state, the opening 20 d of the rotary valve 20 is positioned at the second upstream end openings 15 a to 18 a and the internal space 22 of the surge tank 10. The first upstream end openings 11a to 14a are closed while communicating.
[0054]
Further, as shown in FIG. 9, when the engine speed is between the low speed side operation state and the high speed side operation state, the opening 20d of the rotary valve 20 is connected to the first upstream end openings 11a to 14a and the second upstream side. It exists in the transient state which exists in the position straddling end opening part 15a-18a, and all open.
[0055]
Next, the operation of the intake device 7 will be described.
[0056]
When the engine 1 is operating on the low speed side (operating state on the low speed rotation side), as shown in FIG. 7, the rotary valve 20 is rotationally driven by the actuator 21 as necessary, and the internal space 22 of the surge tank 10 The first upstream end openings 11 a to 14 a are communicated, and the second upstream end openings 15 a to 18 a are held closed by the rotary valve 20. At this time, the intake air passes from the surge tank 10 to the intake port 8 via the first upstream end openings 11a to 14a, the first pipe portions 11b to 14b, the second pipe portions 11c to 14c, and the third pipe portions 11d to 14d. Since the passage length from the surge tank 10 to the intake port 8 is increased, the intake charge efficiency in the low-speed side operation state is increased due to the inertia effect.
[0057]
In addition, since the second pipe portions 11c to 14c where the second branch passages 15 to 18 merge with the first branch passages 11 to 14 are continuous in a straight line, the passage resistance at the joining portion is reduced, and the intake air charging is performed. The reduction in efficiency can be suppressed.
[0058]
On the other hand, when the engine 1 is in a high-speed operation state (operation state on the high-speed rotation side), as shown in FIG. 8, the rotary valve 20 is rotationally driven as necessary by the actuator 21, and the internal space 22 of the surge tank 10. And the second upstream end openings 15 a to 18 a are communicated, and the first upstream end openings 11 a to 14 a are held closed by the rotary valve 20. At this time, the intake air is filled in the intake port 8 from the surge tank 10 through the second upstream end openings 15a to 18a and the second pipe portions 11c to 14c, and the passage length from the surge tank 10 to the intake port 8 is filled. Therefore, the intake charge efficiency in the high-speed side operation state is increased due to the inertia effect.
[0059]
Further, when the engine 1 is switched from the low-speed operation state to the high-speed operation state, as shown in FIG. 9, the rotary valve 20 is rotationally driven by the actuator 21 as necessary, so that the first upstream end opening Both 11a-14a and the 2nd upstream end opening 15a-18a will be in the state opened partially. At this time, the sum of the areas of the opened portions of the first upstream end openings 11a to 14a and the second upstream end openings 15a to 18a is equal to or larger than the opening area of the first upstream end openings 11a to 14a. By setting it so that it becomes more than the opening area of 2 upstream end opening parts 15a-18a, an intake outflow resistance becomes small and it can suppress that intake filling efficiency falls.
[0060]
According to the engine intake device 7 of the first embodiment described above, the following effects can be obtained.
[0061]
a) A transient state in which the rotary valve 20 is located across the first upstream end openings 11a to 14a and the second upstream end openings 15a to 18a when switching from the low speed side operation state to the high speed side operation state. In this case, since the intake air outflow area is equal to or larger than the intake air outflow area in the low speed side operation state and the high speed side operation state, the intake air outflow resistance is reduced in this transient state, and the intake charge efficiency at the time of switching is reduced. It is possible to minimize the deterioration.
[0062]
b) The first upstream end openings 11a, 14a and 12a, 13a overlap in the radial direction on the outer periphery of the surge tank 10 and are formed close to the center in the left-right direction. Since it is arranged so as to surround the portion, it is possible to make the intake device 7 compact while ensuring the length of the first branch passages 11 to 14 necessary for obtaining the inertia effect in the low-speed side operation state. It is also advantageous in terms of installation space.
[0063]
c) The length of the surge tank 10 in the left-right direction is formed shorter than the distance between the two intake ports 8 corresponding to the cylinders 3A, 3D at the left and right ends, respectively, and among the four first upstream end openings 11a-14a The two first upstream end openings 11a, 12a on the right side and the two first upstream end openings 13a, 14a on the left side are formed so as to partially overlap each other in the outer peripheral portion of the surge tank 10, and the two Since the first upstream end openings 11a and 12a and the two left first upstream end openings 13a and 14a are also close to each other, the passage length from the throttle valve 24a to the first upstream end openings 11a to 14a is approximately. In addition, the natural frequency between the first branch passages 11 to 14 and the second branch passages 15 to 18 can be unified, and the charging efficiency can be made uniform.
[0064]
Further, the two first branch passages 12 and 13 corresponding to the two central cylinders 3B and 3C are further lowered below the first branch passages 11 and 14 corresponding to the two cylinders 3A and 3D at the left and right ends. Since it is curved, the passage lengths from the surge tank 10 to the intake port 8 in the four first branch passages 11 to 14 are substantially equal in the low-speed operation state. Accordingly, in the four first branch passages 11 to 14, the passage lengths from the throttle valve 24a to the intake port 8 are substantially equal, and the difference in frequency of pressure pulsation due to the difference in passage length is also reduced. The unpleasant sound caused by the noise can be minimized in the low-speed side driving state where the noise of the engine 1 is small and the influence of the unpleasant sound on the outside is large.
[0065]
In addition, since the four second upstream end openings 15a to 18a are also formed close to each other on the outer peripheral portion of the surge tank 10, the intake air from the throttle valve 24a is obtained in the second branch passages 15 to 18 even in the high speed side operation state. Since the difference in the passage length to the port 8 is small, it is possible to suppress the unpleasant noise even in the high speed side operation state. Further, since the volume of the surge tank 10 can be reduced, the response can be improved.
[0066]
d) Since the rotary valve 20 is mounted on the surge tank 10 so as to be able to rotate, almost no space for disposing the rotary valve 20 is required, and the intake device 7 can be made compact.
[0067]
e) The second branch passages 15a to 18a are continuously joined linearly to the second pipe portions 11c to 14c of the first branch passages 11a to 14a. It is possible to suppress a reduction in the intake air charging efficiency due to a decrease in the passage resistance. Further, since the third pipe portions 11d to 14d are also smoothly curved, the passage resistance is reduced even in the high-speed side operation state, and it is possible to suppress a reduction in the intake charging efficiency.
[0068]
f) Second positions corresponding to the cylinders 3B and 3C at the center in the cylinder row direction when the lower end position P1 of the first branch passages 11 and 14 corresponding to the cylinders 3A and 3D at both ends in the cylinder row direction is viewed from one side in the cylinder row direction. Since it is arranged at a position higher than the lower end position P2 of the branch passages 12 and 13, the passage length from the surge tank 10 to each cylinder can be made substantially equal, and the length for obtaining the inertia effect in the low speed side operation region can be secured, so that torque Improvements can be made. Further, a step space is formed at both ends of the first branch passages 11 and 14 in the cylinder row direction, so that accessories can be arranged in this space.
[Second Embodiment]
Next, an engine intake device according to a second embodiment of the present invention will be described.
[0069]
In addition, although the same number is attached | subjected to the element same as 1st Embodiment, description is abbreviate | omitted, but this 2nd Embodiment abbreviate | omits the 2nd branch passages 15-18 of the 1st Embodiment and the rotary valve 20. This configuration can also be applied.
[0070]
FIG. 11 is a front view of an intake device for an engine according to the second embodiment of the present invention, FIG. 12 is a plan view of the intake device for the engine according to the second embodiment of the present invention, and FIG. 13 is a second embodiment according to the present invention. 14 is a cross-sectional view taken along the line II-II in FIG. 13, and FIG. 15 is a view of the engine intake device according to the second embodiment of the present invention as viewed from the engine unit side. In the engine intake device 27 of the second embodiment, first branch passages 31 to 34 are provided so as to surround the surge tank 10 as in the first embodiment, and the first branch passages 31 to 34 are connected to the surge tank 10. The first upstream end openings 31a to 34a connected to the outer peripheral portion of the cylinder, and the first upstream end openings 31a to 34a that extend obliquely upward from the first upstream end openings 31a to 34a toward the engine unit 2 and are curved downward and straight below the surge tank 10. Extend to The first pipe portions 31b to 34b, the second pipe portions 31c to 34c extending linearly above the surge tank 10 while being curved to the anti-engine unit 2 side below the surge tank 10, and the engine unit above the surge tank 10 It has the 3rd pipe parts 31d-34d connected via the attachment flange 25 to the intake port 8 which curves and extends to the 2 side and opens to the side surface of the engine 1.
[0071]
Similarly to the first embodiment, the second branch passages 15 to 18 are provided, and obliquely upward in the direction away from the engine unit 2 from the second upstream end openings 15 a to 18 a connected to the outer peripheral portion of the surge tank 10. The second branch portions 31c to 34c of the first branch passages 31 to 34 are joined in the middle of the straight portions.
[0072]
The second pipe portions 31c to 34c extending upward from below the surge tank 10 in the first branch passages 31 to 34 are arranged in a substantially planar shape in the cylinder row direction on the side opposite to the engine unit 2 and are located at both ends in the cylinder row direction. The lower end position P1 of the pipe parts 31c and 34c is arranged at a position higher than the lower end position P2 of the second pipe parts 32c and 33c located at the center in the cylinder row direction when viewed from one side in the cylinder row direction.
[0073]
Further, the first pipe portions 31b to 34b that are curved from the upper side of the surge tank 10 and extend downward in the first branch passages 31 to 34 are formed so as to be arranged in a substantially planar shape in the cylinder row direction on the engine unit 2 side. .
[0074]
Of the first branch passages 31 to 34, the branch passages 31 and 34 positioned at both ends in the cylinder row direction are the first pipe portions 31b and 34b after branching from the surge tank 10 are located at the center in the cylinder row direction. Curved at a position higher than the first pipe portions 32b and 33b of the branch passages 32 and 33, spreads on both sides of the first branch passages 32 and 33 located at the center in the cylinder row direction and extends below the surge tank 10.
[0075]
Further, the first branch passages 31 and 34 corresponding to the cylinders 3A and 3D at both ends in the cylinder row direction overlap with each other in the cylinder row direction and branch upward from the surge tank 10, and the cylinders 3A and 3A are connected via the first common branch passage 30A. The first branch passages 32 and 33 extending in 3D and corresponding to the cylinders 3B and 3C at the center in the cylinder row direction overlap with each other in the cylinder row direction and branch downward from the surge tank 10 via the second common branch passage 30B. It extends to 3B and 3C.
[0076]
The outer periphery of the surge tank 10 has a first common opening 30a that opens toward the first upstream end openings 31a and 34a corresponding to the cylinders 3A and 3D at both ends in the cylinder row direction, and a cylinder 3B in the center in the cylinder row direction. , 3C corresponding to the first upstream end openings 32a, 33a and the second common opening 30b that opens toward the first upstream end openings 32a, 33a, and the first branch passages 11 through the first and second common branch passages 30A, 30B. Inlet air is introduced to -14.
[0077]
Each of the first upstream end openings 31 a to 34 a is formed near the top of the outer peripheral portion of the surge tank 10. Among these four first upstream end openings 31a to 34a, the first upstream end openings 31a and 34a corresponding to the cylinders 3A and 3D at both ends in the cylinder row direction are close to each other in the cylinder row direction and are located in the center in the cylinder row direction. The first upstream end openings 32a and 33a corresponding to the cylinders 3B and 3C at the center in the cylinder row direction extend below the surge tank 10 than the first upstream end openings 31a and 34a, and are located in the center in the cylinder row direction. The first upstream end openings 32 a and 33 a located at the outer periphery of the surge tank 10 overlap with each other on substantially the same circumference to form a common branch passage 30. That is, the four first upstream end openings 31a to 34a are formed close to each other in the vicinity of the central portion in the left-right direction of the surge tank 10, and from the throttle valve 24a to the four first upstream end openings 31a to 34a. The passage lengths are substantially equal.
[0078]
As shown in FIGS. 14 and 15, the first upstream end openings 31a and 34a of the first branch passages 31 and 34 corresponding to at least the cylinders 3A and 3D at both ends in the cylinder row direction and the cylinders 3B and 3C in the center in the cylinder row direction are provided. And the first upstream end openings 32a and 33a of the first branch passages 32 and 33 are inclined in the intake flow direction S1 of the surge tank 10 and surround the surge tank 10 in a spiral shape. Further, the flow path cross-sectional shape of the first branch passages 31 to 34 is formed in a substantially parallelogram inclined in the intake flow direction of the surge tank 10.
[0079]
Other configurations such as a rotary valve are the same.
[0080]
According to the engine intake device 27 of the second embodiment described above, the following effects can be obtained in addition to the effects of the first embodiment.
[0081]
a) Second positions corresponding to the cylinders 3B and 3C at the center in the cylinder row direction when the lower end position P1 of the second branch passages 31 and 34 corresponding to the cylinders 3A and 3D at both ends in the cylinder row direction is viewed from one side in the cylinder row direction. Since it is arranged at a position higher than the lower end position P2 of the branch passages 32, 33, the passage length from the surge tank 10 to each cylinder can be made substantially equal, and the length for obtaining the inertia effect in the low speed side operation region can be ensured. Improvements can be made. Further, as shown in FIG. 16 showing a front view of the engine 1, the engine can be miniaturized, and step space SP is formed at both ends in the cylinder row direction below the first branch passages 31 and 34. Therefore, the starter motor 41 is formed in this space SP. And auxiliary equipment such as an air conditioner compressor 42 can be arranged.
[0082]
In FIG. 16, the engine unit 2 includes a cylinder block 2a, a cylinder head 2b, a head cover 2c, and an oil pan 2d. A starter motor 41 meshes with a flywheel 43 to drive the crankshaft. An oil filter 44 is provided below the starter motor 41.
[0083]
b) Since the first branch passages 31 to 34 are formed so as to be arranged in a substantially flat shape in the cylinder row direction on the engine unit 2 side and the anti-engine unit 2 side, the size of the engine in the front-rear direction can be reduced. As shown in FIG. 17 showing the right side view of FIG. 1, there is a space for arranging the intake device 27 between the front and rear directions of the vehicle body of the radiator unit 45 including the radiator and the electric fan disposed in front of the engine room and the engine unit 2. It can be secured.
[0084]
(C) First upstream passages 31a, 34a of first branch passages 31, 34 corresponding to cylinders 3A, 3D at both ends in the cylinder row direction and first branch passages corresponding to cylinders 3B, 3C in the center of the cylinder row direction. Since the first upstream end openings 32a and 33a of 32 and 33 are inclined in the intake flow direction S1 of the surge tank 10, the intake flow resistance from the surge tank 10 to the first branch passages 31 to 34 is reduced. Can be reduced.
[0085]
(D) The flow path cross-sectional shape of the first branch passages 31 to 34 is formed in a substantially parallelogram inclined in the intake flow direction of the surge tank 10, so that the intake air flows along the inner wall of the passage. By reflecting on the inner wall of the passage, the secondary flow that becomes a spiral component can be suppressed, the intake pressure loss can be reduced, and the average flow coefficient (Cf) can be increased.
[Third Embodiment]
Next, as the engine intake device of the third embodiment according to the present invention, the structure of the intake port 8 of the cylinder head 2b and the structure of the first branch passages 11 to 14 near the connection portion with the intake port 8 will be described. To do.
[0086]
In addition, although the same number is attached | subjected to the element same as 1st Embodiment, description is abbreviate | omitted, but this 3rd Embodiment is the structure combined with the intake device of 1st or 2nd Embodiment, and other The present invention can also be applied to combinations with different intake device configurations, and can also be applied to configurations in which the second branch passages 15 to 18 and the rotary valve 20 of the first embodiment are omitted.
[0087]
18 is a cross-sectional view of the engine in the lateral direction showing the intake device for the engine according to the third embodiment of the present invention, FIG. 19 is an external view of the shutter valve, and FIG. 20 is an illustration of the engine of the second embodiment according to the present invention. FIG. 21 is a sectional view in the passage when the shutter valve is opened, FIG. 22 is a sectional view in the passage when the shutter valve is closed, and FIG. 23 is a sectional view taken along XXI-XXI in FIG. 24 is a sectional view taken along the line IV-IV in FIG. 21, FIG. 25 is a sectional view taken along the line VV in FIG. 21, and the intake device 37 of the engine of the third embodiment takes the intake air obliquely upward from the four cylinders 3A to 3D. The port 8 and the third pipe portions 11d to 14d of the first branch passages 11 to 14 connected to the intake port 8 extend upstream. The upstream side of the first branch passages 11 to 14 (not shown) has a structure similar to that shown in FIGS.
[0088]
Further, in the vicinity of the downstream end openings 11e to 14e connected to the intake port 8 in the first branch passages 11 to 14 (third pipe portions 11d to 14d), a part of the flow path cross section of the passages 11 to 14 is provided. A shutter valve 51 that closes and generates a tumble flow in the cylinder 3 is rotatably supported by a shaft 52 that passes through the axis of each of the first branch passages 11 to 14 and crosses the approximate center of the flow path cross section.
[0089]
As shown in FIG. 19, the shutter valve 51 includes a lower half 51a that closes the flow path section of the first branch passages 11-14 below the shaft 52 when fully closed, and a flow path section above the shaft 52 when fully closed. It has a lower half 51b in which a portion above the shaft 52 is notched (bent in the downstream direction around the middle of the cross section of the flow path) so as not to be blocked.
[0090]
And the inner wall of the part P3 which is not obstruct | occluded by the shutter valve 51 in the upstream 1st branch channel | path and 11-14 and the downstream intake port 8 across the shutter valve 51 is conventional structure (dotted line part P3 'of FIG. 18). Is formed in a substantially linear shape, and is closed by the shutter valve 51 in the upstream first branch passages 11 to 14 and the downstream intake port 8 across the shutter valve 51 (arrow portion in FIG. 18). The inner wall of P4) is formed so as to swell in the radial direction at the position where the shutter valve 51 is disposed, and the flow path cross-sectional area of the first branch passages 11 to 14 at the position where the shutter valve 51 is disposed is upstream of the shutter valve 51. And larger than the downstream cross-sectional area.
[0091]
Further, when viewed from one side in the cylinder row direction of the engine (the front and back direction in the drawing in FIG. 18), the inclination angle θ2 of the first branch passages 11 to 14 obliquely upward is relative to the inclination angle θ1 of the intake port 8. It is getting bigger.
[0092]
The inner wall of the upper portion of the intake port 8 where the valve guide 5a is disposed is formed flat compared to the conventional structure (dotted line portion P5 ′ in FIG. 18) in the upstream to downstream section of the valve guide 5a. The flat portion P5 is formed so as to reduce the flow path area in the upper portion of the intake port 8 where the valve guide 5a is provided.
[0093]
Furthermore, the cross section of the flow path from the vicinity of the branch portion of each intake port 8a that branches into two and communicates with each of the cylinders 3A to 3D to the throat portion P6 where the flow area of the downstream is narrowed branches into the two. The upper portion 8b, the side surface portion 8c, and the lower portion 8c are formed to be flat and rectangular as compared with the conventional structure (dotted line portion 8a ′ in FIG. 23) on the side between the intake ports 8a to be branched into the two. The side surface portion 8e is formed in a round shape on the side between the anti-intake ports 8.
[0094]
The cross-sectional shape of the intake port 8 in the section from the upstream to the downstream of the valve guide 5a is a connecting portion between the intake port 8 and the first branch passages 11 to 14 in which the inner wall of the upper portion is made substantially linear and the inner wall of the lower portion is expanded. Although it can be applied in combination with a nearby configuration as appropriate, it is preferable to combine both configurations.
[0095]
According to the engine intake device of the third embodiment described above, the following effects can be obtained.
[0096]
19) As shown in FIG. 19, the shutter valve 51 is cut out at a position above the shaft 52 so as not to block the flow path cross section above the first branch passages 11-14 when fully closed. The inner wall of the portion P3 that is not blocked by the shutter valve 51 in the upstream first branch passages 11 and 14 and the downstream intake port 8 is formed in a substantially straight line, thereby reducing the intake flow resistance and the shutter valve. When the valve 51 is closed, the intake air flows along the inner wall above the passage to enhance the tumble flow, while the shutter valve 51 is interposed between the upstream first branch passages 11 to 14 and the downstream intake port 8. The inner wall of the portion closed by the shutter valve 51 is formed so as to swell in the radial direction at the position where the shutter valve 51 is disposed, and the first branch passage 11 at the position where the shutter valve 51 is disposed. The flow path cross-sectional area of 14, that was larger than the upstream and downstream of the flow path cross-sectional area of the shutter valve 51, can be reduced tumble flow becomes weak flow resistance at the time of opening of the shutter valve 51. With this configuration, an engine with low fuel consumption and high output can be obtained.
[0097]
b) In the first branch passages 11 to 14 formed so as to surround the surge tank 10 in order to increase the passage length, the shutter valve 51 is closed while ensuring high output when the shutter valve 51 is opened. Sometimes the tumble flow can be strengthened.
[0098]
c) The inner wall of the upper portion of the intake port 8 in which the valve guide 5a is disposed is formed flat in the section from the upstream to the downstream of the valve guide 5a, and this flat portion P5 is the intake air in which the valve guide 5a is provided. Since the flow passage area in the upper part of the port 8 is formed so as to be reduced, the flow attenuation by the inner wall surface of the upper part of the intake port 8 can be suppressed.
[0099]
d) The cross section of the flow path from the vicinity of the branch portion of each intake port 8 that branches into two and communicates with each of the cylinders 3A to 3D to the throat portion P6 in which the flow area on the downstream side thereof is narrowed is 2 The upper portion 8b, the side surface portion 8c and the lower portion 8d are formed in a flat and rectangular shape on the side between the intake ports 8 branched into two, and the side surface portion 8e is formed on the side between the anti-intake ports 8 branched into the two. Since it is formed in a round shape, as shown in FIG. 24, when the shutter valve 51 is opened, it follows the upper portion 8b and the lower portion 8d of the flow path cross section from the first branch passages 11 to 14 to each intake port 8. While increasing the intake air flow rate to ensure high output, as shown in FIG. 25, when the shutter valve 51 is closed, the intake air flow velocity in the upper portion 8b of the cross section of the flow path from the first branch passages 11-14 to each intake port 8 is closed. Increase Strengthen Bull stream, it is possible to enhance the intake charging efficiency.
[Brief description of the drawings]
FIG. 1 is a front view of an intake device for an engine according to a first embodiment of the present invention.
FIG. 2 is a plan view of the engine intake device of the first embodiment according to the present invention.
FIG. 3 is a right side view of the engine intake device of the first embodiment according to the present invention.
FIG. 4 is a left side view of the intake device for the engine according to the first embodiment of the present invention.
5 is a cross-sectional view taken along the line II of FIG.
FIG. 6 is a perspective view of a rotary valve.
7 is an enlarged view of a main part of FIG. 5 (low-speed side operation state).
8 is an enlarged view of a main part of FIG. 5 (high-speed side operation state).
FIG. 9 is an enlarged view (transient state) of the main part of FIG.
FIG. 10 is a development view of a rotary valve.
FIG. 11 is a front view of an engine intake device according to a second embodiment of the present invention.
FIG. 12 is a plan view of an engine intake device according to a second embodiment of the present invention.
FIG. 13 is a right side view of an intake device for an engine according to a second embodiment of the present invention.
14 is a cross-sectional view taken along the line II-II in FIG.
FIG. 15 is a view of an engine intake device according to a second embodiment of the present invention as viewed from the engine unit side.
FIG. 16 is a front view of an engine equipped with an intake device for an engine according to a second embodiment of the present invention.
FIG. 17 is a right side view of an engine equipped with an intake device for an engine according to a second embodiment of the present invention.
FIG. 18 is a cross-sectional view in the short-side direction of the engine showing the engine intake device of the third embodiment according to the present invention.
FIG. 19 is an external view of a shutter valve.
FIG. 20 is a plan view of an intake system for an engine according to a second embodiment of the present invention.
FIG. 21 is a sectional view in the passage when the shutter valve is opened.
FIG. 22 is a sectional view in the passage when the shutter valve is closed.
23 is a cross-sectional view taken along the line III-III in FIG.
24 is a cross-sectional view taken along the line IV-IV in FIG.
25 is a cross-sectional view taken along the line VV in FIG.
FIG. 26 is a longitudinal sectional view of a conventional intake device.
FIG. 27 is an operation explanatory diagram of a conventional intake device.
[Explanation of symbols]
1 engine
2 Engine unit
2a Cylinder block
2b Cylinder head
2c Head cover
2d oil pan
3A-3D cylinder
5 Intake valve
6 Exhaust valve
7, 27, 37 Intake device
8,8a Intake port
9, 9a Exhaust port
10 Surge tank
10a, 10b, 30a, 30b opening
11-14, 31-34 1st branch passage
11a-14a, 31a-34a First upstream end opening
15-18 Second branch passage
15a-18a Second upstream end opening
20 Rotary valve
23 Intake pipe
24 Throttle body
24a Throttle valve
30 Common branch passage
41 Starter motor
42 Air-conditioning compressor
43 Flywheel
44 Oil pan
45 Radiator unit
51 Shutter valve

Claims (8)

A branch passage that branches off from the collective passage and communicates with each cylinder of the engine extends from the collective passage, curves downward from the engine unit side to the collective passage, and extends from the anti-engine unit side of the collective passage to the top of the collective passage. In an intake device of an engine that is curved and surrounds the collecting passage and is connected to an intake port of the engine,
The connecting position of the branch passage with respect to the collective passage is set at an upper portion of the collective passage, and each of the branch passages is curved from the upper portion of the collective passage to the engine unit side and extends downward.
Of the branch passages, the connection position of the branch passages located at both ends in the cylinder row direction to the collective passage is a portion farther from the engine unit than the connection position of the branch passage located in the center of the cylinder row direction to the collective passage,
Below the collecting passage, the branch passages are arranged in the cylinder row direction, and the lower end position of the branch passage below the collecting passage of the branch passages located at both ends of the cylinder row direction is viewed from one side in the cylinder row direction. An engine intake device, wherein the intake system is disposed at a position higher than a lower end position of the branch passage below the collective passage of the branch passage located in the center in the cylinder row direction.   2. The engine according to claim 1, wherein the branch passages located at both ends in the cylinder row direction are branched through a common passage overlapping with a branch passage located at the center in the cylinder row direction extending from the collecting passage. Inhalation device.   The branch passages located at both ends in the cylinder row direction are branched from the collecting passage, and then curved at a position higher than the branch passage located in the center in the cylinder row direction, and the cylinders of the branch passage located in the center in the cylinder row direction 3. The engine intake device according to claim 2, wherein the engine intake device extends to both ends in the row direction and extends below the collecting passage.   4. The engine intake device according to claim 2, wherein a plurality of branch passages located in the center in the cylinder row direction are provided, and extend from the collective passage to each cylinder through the common passage. 5.   The branch passage located at both ends of the cylinder row direction and the branch passage located at the center of the cylinder row direction are linearly arranged in the cylinder row direction on the engine unit side of the collective passage. Engine intake system.   At least an upstream end opening of the branch passage located at both ends in the cylinder row direction and an upstream end opening of the branch passage located at the center in the cylinder row direction are inclined in the intake flow direction of the collective passage. The engine intake device according to any one of claims 1 to 5.   The engine intake device according to any one of claims 1 to 6, wherein all upstream end openings of the branch passage are inclined in an intake flow direction of the collecting passage. Each branch passage claims, characterized in that it is curved downward side of the merge passage while extending obliquely upward to the engine unit side from the opening of connected the respective branch passages and the manifolds The engine intake device according to any one of 1 to 6.

Images