JP2009167879A - Air intake system structure of multi-cylinder internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air intake system structure of an in-line multi-cylinder internal combustion engine capable of improving acoustic characteristics caused by the interference of air intake pulsation. <P>SOLUTION: Air intake single pipes 31-34 of equal lengths for making each cylinder of the in-line four-cylinder engine communicate with a surging tank 20 are arranged in parallel on the surging tank 20, and an inlet port 22a common to each cylinder is formed on the side wall 26 of an upstream of the surging tank 20. A second shutoff plate 42 having distribution ports 42a-42e is provided in the surging tank 20, and a first shutoff plate 41 having distribution ports 41a-41d is slidably disposed along the second shutoff plate 42. The deviation of a distance from respective connection ports 31a-34a of the air intake single pipes 31-34 with the surging tank 20 to the inlet port 22a is made to be variable by changing distribution states of the distribution ports 41a-41d with the distribution ports 42a-42e by sliding the first shutoff plate 41 along the second shutoff plate 42. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an intake system structure in a multi-cylinder internal combustion engine.

  The intake system of a multi-cylinder internal combustion engine allows intake air to flow from the air intake port upstream of the air cleaner to the intake port of the engine. Usually, the air intake port, air cleaner, throttle body with a throttle valve for adjusting the intake air amount, intake air It is configured by connecting intake system components such as a surge tank for suppressing pulsation and an intake manifold for distributing intake air to each cylinder through an intake passage. Since each of these intake system components is fixed to the internal combustion engine or the vehicle body, the length of the intake passage connecting them is usually constant.

In addition, in an intake system of an in-line multi-cylinder internal combustion engine, due to restrictions when mounted on a vehicle, an intake port through which intake air flows is formed on the side wall on the upstream side of the surge tank, and each cylinder is formed on the side wall of the surge tank. In many cases, a configuration is adopted in which the suction ports of the intake manifold connected to are opened so as to be sequentially arranged downstream (for example, Patent Document 1). Here, particularly at low and medium loads, it is desirable to suppress the generation of unpleasant timbre due to interference of intake pulsation, that is, to reduce the non-integer order component (half order component) of the intake air and create a smooth timbre. . For this purpose, the length of the intake manifold from each intake port to the intake port of each cylinder in the surge tank is matched between the cylinders, and the intake port of the surge tank is connected from the intake port of each cylinder to the same intake port. It is necessary to provide at a position where the distances are equal.
Japanese Patent Laid-Open No. 9-88744

  However, in the intake system having the structure as disclosed in Patent Document 1, even if the intake manifold is formed to have the same length, the surge tank may vary depending on the opening position of each connection port (each intake port) between the surge tank and the manifold. The distance from the intake port to the intake port of each cylinder varies. For this reason, a difference occurs in the propagation path of each pulsation generated from the intake manifold in the surge tank, and as a result, it is difficult to realize the above-described tone color.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide an intake system structure of an in-line multi-cylinder internal combustion engine that can improve the characteristics of acoustics generated by interference of intake pulsation. .

In the following, means for achieving the above object and its effects are described.
According to the first aspect of the present invention, an equal-length intake manifold that communicates each cylinder of a multi-cylinder internal combustion engine and a surge tank is arranged in parallel, and intake air is sucked into the side wall of the upstream portion of the surge tank. In an intake system structure of a multi-cylinder internal combustion engine in which a common suction port is formed and each connection port between the manifold and the surge tank is sequentially arranged downstream, the intake air is disposed in the surge tank. A plurality of blocking plates formed with flowable flow ports, and a deviation of the distance from each connection port to the suction port by changing the flow state of the flow ports by relatively moving the plurality of blocking plates The gist of the present invention is to provide a drive mechanism that makes the variable.

  According to the above configuration, since the plurality of blocking plates are provided in the surge tank and formed with circulation ports through which intake air can flow, intake air circulates through the circulation port and intake pulsation is propagated. A drive mechanism that varies the flow state of the flow port by moving the plurality of blocking plates relative to each other so that the deviation in distance from the connection port between the manifold and the surge tank to the suction port is variable. Therefore, by reducing the deviation of the distance from each connection port between the manifold and the surge tank to the suction port, it is possible to reduce the explosion non-integer order component and make a smooth tone. As a result, for example, by relatively moving the plurality of shut-off plates according to the operating state of the internal combustion engine, it is possible to improve the characteristics of the sound generated by the interference of intake pulsation.

  Specifically, as described in claim 2, the plurality of blocking plates are formed in substantially the same size and arranged in parallel to each other, and the formation positions of the flow ports in the plurality of blocking plates are By adopting a configuration in which each blocking plate is different, the deviation of the distance from each connection port to the surge tank to the suction port can be easily made variable.

  According to a third aspect of the present invention, there are provided an equal-length intake manifold that communicates each cylinder of a multi-cylinder internal combustion engine and a surge tank in parallel, and supplies intake air to a side wall at an upstream portion of the surge tank. In the intake system structure of a multi-cylinder internal combustion engine in which a common suction port is formed and the connection ports of the manifold and the surge tank are sequentially arranged downstream, the inside of the surge tank of the manifold The suction port is formed at a position where the distance between each tip of the manifold and the suction port becomes longer as the protrusion length of the manifold becomes longer, and the manifold is closer to the suction port in the surge tank. The gist of the invention is to connect the surge tank at a predetermined angle with respect to the wall surface of the surge tank so that the length of the protrusion is longer.

  According to a fourth aspect of the present invention, an equal-length intake manifold that communicates each cylinder of a multi-cylinder internal combustion engine with a surge tank is arranged in parallel, and intake air is supplied to the upstream side wall of the surge tank. In the intake system structure of a multi-cylinder internal combustion engine in which a common suction port is formed and the connection ports of the manifold and the surge tank are sequentially arranged on the downstream side, the surge tank of the manifold The suction port is formed at a position where the distance between each tip of the manifold and the suction port becomes shorter as the projecting length in the interior becomes longer, and the surge tank is closer to the suction port. The gist of the invention is that the connection is made at a predetermined angle with respect to the wall surface of the surge tank so that the protruding length inside is shortened.

  According to the configuration of claim 3 or 4, the length of the intake manifold is maintained at an equal length, and the protruding length of the intake manifold in the surge tank is determined according to the connection position to the surge tank. Each length can be set. Accordingly, it is possible to reduce the difference in the propagation path of the intake pulsation between the cylinders and improve the characteristics of the sound generated by the interference of the intake pulsation.

  In the invention according to claim 5, each of the equal-length intake manifolds communicating the respective cylinders of the multi-cylinder internal combustion engine and the surge tank is arranged in parallel and the intake air is supplied to the side wall of the upstream portion of the surge tank. In an intake system structure of a multi-cylinder internal combustion engine in which a common suction port is formed and connection ports of the manifold and the surge tank are sequentially arranged downstream, the manifold is placed in the surge tank. A partition plate that protrudes and adjusts the protruding length of the manifold in the intake circulation portion in the surge tank; and the manifold is adjusted by moving the partition plate relative to the manifold And a drive mechanism that makes the deviation of the intake air flow distance from each protruding tip to the suction port variable.

  According to the above configuration, the non-integral order component of the explosion is obtained by reducing the deviation of the intake flow distance from each protruding tip of the manifold to the inlet while maintaining the length of the intake manifold equal. Can be made smoother. As a result, for example, by moving the partition plate according to the operating state of the internal combustion engine, it is possible to improve the characteristics of the sound generated by the interference of intake pulsation.

  Specifically, as described in claim 6, the partition plate is pivotally supported in the surge tank so as to be rotatable around one end, and the drive mechanism is connected to each tip from which the manifold protrudes. It is possible to employ a configuration in which each distance to a portion intersecting with the partition plate is adjusted so as to become longer as it approaches the suction port.

(First embodiment)
Hereinafter, a first embodiment in which an intake system of a multi-cylinder internal combustion engine according to the present invention is embodied in a surge tank of an in-line four-cylinder engine will be described with reference to FIGS.

  FIG. 1 is a perspective view of a surge tank 20 in the present embodiment. In FIG. 1, the surge tank 20 has an upper tank 20 a and a lower tank 20 b that are semicircular in outer cross section perpendicular to the longitudinal direction. Then, by joining the peripheral edge of the upper tank 20a having an opening in the lower part of the figure and the peripheral part of the lower tank 20b having an opening in the upper part of the figure, the outer cross section perpendicular to the longitudinal direction is circular. A surge tank 20 having a shape is formed. A cylindrical suction pipe 22 for sucking intake air is connected to a side wall (a circular side wall on the right side of the drawing) of the surge tank 20 which is an upstream portion of the intake flow, substantially perpendicularly to the side wall. Has been. Here, in the intake system in the present embodiment, similarly to the above-described conventional intake system, an intake intake port, an air cleaner, a throttle body (all not shown) provided with a throttle valve for adjusting the intake air amount from the upstream, The suction pipes 22 are connected in this order.

  1, intake air pipes 31 to 34 having the same length are connected in parallel with each other so as to be substantially perpendicular to the suction pipe 22. The side walls extending in the longitudinal direction of the surge tank 20 in FIG. That is, the connection ports of the intake single pipes 31 to 34 and the surge tank 20 are sequentially arranged in the downstream side. The connection side to the surge tank 20 is the base end of the intake single pipes 31 to 34, and the tips of the intake single pipes 31 to 34 are connection ports of the intake port plate 35 disposed on the side surface of the cylinder head (not shown). 36a to 39a are connected to each other. Further, the tips of the intake single pipes 31 to 34 are connected to the intake ports 36 to 39 disposed in the cylinder head via the connection ports 36a to 39a, respectively. The intake ports 36 to 39 communicate with combustion chambers (not shown) of the respective cylinders. The intake single pipes 31 to 34 are collectively referred to as the intake manifold.

  With the above configuration, the intake air taken in from the intake intake port passes through the air cleaner and the throttle body in this order, and is then sucked into the surge tank 20 through the suction pipe 22. Then, the air sucked into the surge tank 20 is sent to the single intake pipes 31 to 34, and is mixed with the fuel injected from the fuel injection valves (not shown) through the intake ports 36 to 39. Sucked into the combustion chamber of each cylinder.

Next, the internal structure of the surge tank 20 in this embodiment will be described in detail with reference to FIGS.
FIG. 2 shows a cross-sectional view of the surge tank 20. As shown in FIG. 2, the intake single pipes 31 to 34 are connected to the side wall 25 (upper side wall in the figure) extending in the longitudinal direction of the surge tank 20 in parallel at substantially equal intervals. Connection ports 31a to 34a on the base end side of the intake single pipes 31 to 34 are formed so as to open into the surge tank 20, respectively. In addition, the suction pipe 22 is connected to the upstream side wall 26 (right side wall in the figure) of the surge tank 20 at a position farthest from the connection ports 31a to 34a. A suction port 22a is formed so that the pipe 22 and the surge tank 20 communicate with each other.

  By the way, in the surge tank 20 according to the present embodiment, each of the surge tank 20 and the intake single pipes 31 to 34 is different from each other even if the intake single pipes 31 to 34 are formed to have the same length as in the conventional case described above. Depending on the opening positions of the connection ports 31a to 34a, the distance from the suction port 22a of the surge tank 20 to the intake ports 36 to 39 of each cylinder varies. That is, compared with the cylinders, the connection port 31a (the left end in the figure) is formed at a position farthest from the suction port 22a, so that the intake air communicated from the suction port 22a via the connection port 31a. The distance to the port 36 is the largest. On the other hand, since the connection port 34a (the right end in the figure) is formed at a position closest to the suction port 22a, the distance from the suction port 22a to the intake port 39 communicated via the connection port 34a is The smallest. Thus, due to the difference in distance between the cylinders, a difference also occurs in the propagation path of each pulsation generated from the intake single pipes 31 to 34 in the surge tank 20. Therefore, for example, at low and medium loads, explosion non-integer order components increase due to interference of intake pulsation, and as a result, it may be difficult to realize the tone generation as described above.

  Therefore, in the surge tank 20 according to the present embodiment, in addition to the above structure, a drive mechanism described below is further provided to reduce the pulsation propagation path difference between the cylinders as described above.

  In FIG. 2, a first blocking plate 41 and a second blocking plate 42 that are formed in substantially the same size are arranged in parallel with each other in the middle portion of the space in the surge tank 20. Specifically, the second blocking plate 42 is disposed so as to be parallel to the respective opening surfaces of the connection ports 31 a to 34 a of the intake single pipes 31 to 34, and both ends thereof are fixed to the side walls in the surge tank 20. ing. A first blocking plate 41 is slidably disposed on the downstream surface (upper side in the figure) of the second blocking plate 42. In the present embodiment, a control device (not shown) is connected to the drive mechanism of the first blocking plate 41, and a crank angle sensor that detects the rotational phase of the crank angle shaft of the internal combustion engine is connected to the control device. Has been.

  Next, the structure of the first blocking plate 41 and the second blocking plate 42 will be described with reference to FIG. FIG. 3 is a front view showing the structure of the first blocking plate 41 and the second blocking plate 42 as viewed from the connection direction of the intake single tubes 31 to 34 (upward direction in FIG. 2).

  First, the first blocking plate 41 will be described. As shown in FIG. 3, the first blocking plate 41 is formed with flow ports 41 a to 41 d through which intake air can flow. And the intake pulsation produced from each intake single pipe 31-34 is propagated through these circulation ports 41a-41d. Each of the circulation ports 41a to 41d is composed of three holes having the same shape. Here, in the first blocking plate 41 of the present embodiment, the circulation ports 41a, 41c, and 41d are circular holes having substantially the same size, whereas only the circulation port 41b is an elliptical hole. I am doing. The size of the flow port 41b is substantially equal to the other flow ports 41a, 41c, 41d in the vertical direction of FIG. 3, and is a predetermined length longer than the other flow ports 41a, 41c, 41d in the horizontal direction of FIG. It is set large. This predetermined length will be described later.

  Next, the second blocking plate 42 will be described. As shown in FIG. 3, similarly to the first blocking plate 41, the second blocking plate 42 is also formed with flow ports 42 a to 42 e through which intake air can flow. And the intake pulsation produced from each intake single pipe 31-34 is propagated through these circulation ports 42a-42e. In addition, the circulation ports 42a to 42e each have three holes having the same shape, and the circulation ports 42a to 42e all have circular holes having substantially the same size. In addition, as shown in FIG. 2, the circulation ports 42 a, 42 b, 42 d and 42 e are formed at positions facing the connection ports 31 a to 34 a between the intake single pipes 31 to 34 and the surge tank 20. Specifically, in order from the left in the figure, the flow port 42a faces the connection port 31a, the flow port 42b faces the connection port 32a, the flow port 42d faces the connection port 33a, and the flow port 42e faces the connection port 34a. Is formed. Further, as shown in FIG. 3, the circulation port 42c is formed at an intermediate position between the circulation port 42b and the circulation port 42d in the horizontal direction of FIG. Further, the flow ports 41a, 41c, 41d of the first blocking plate 41 and the flow ports 42a, 42d, 42e of the second blocking plate 42 are formed to have the same size, and the first is shown in FIGS. At the relative positions of the blocking plate 41 and the second blocking plate 42, they are arranged so that their flow ports coincide.

  Here, in the present embodiment, the crank angle sensor is slid by sliding the first blocking plate 41 along the intake downstream surface of the second blocking plate 42 without changing the basic configuration described above. The intake pulsation path difference suitable for the engine speed (high or low) detected from the above is realized. Below, the mode of the combination of each of the first blocking plate 41 and the second blocking plate 42 at the time of high rotation and low rotation will be described.

  First, the high rotation speed will be described with reference to FIGS. As shown in FIG. 2, the first blocking plate 41 at the time of high rotation is arranged so that the left end portion of the same figure and the left side wall of the surge tank 20 in the same figure are in contact. In addition, with respect to the respective flow ports 41a to 41d of the first blocking plate 41, the flow port 41a is connected to the connection port 31a, a part of the flow port 41b is connected to the connection port 32a, and the flow port 41c is connected in order from the left in FIG. The port 33a and the circulation port 41d are formed at positions facing the connection port 34a. Here, the flow port 41b has a left end portion in the drawing overlapping the flow port 42b of the second blocking plate 42 and a right end portion overlapping the flow port 42c of the second blocking plate 42. That is, as shown in FIG. 3, in the circulation ports 41a to 41d of the first blocking plate 41 and the circulation ports 42a to 42e of the second blocking plate 42, the circulation port 41a and the circulation port 42a, the circulation port 41b and the circulation port 42b. The distribution port 41b and the distribution port 42c, the distribution port 41c and the distribution port 42d, and the combination of the distribution port 41d and the distribution port 42e are overlapped. The predetermined length of the flow port 41b of the first blocking plate 41 is a length set so as to overlap the flow ports 42b and 42c of the second block plate 42. That is, in the horizontal direction of the figure, the length is set to approximately half the distance from the center of the connection port 32a to the center of the connection port 33a.

  Next, how the intake pulsation propagates during high rotation will be described. In FIG. 2, the state in which intake pulsation flows through the flow ports 41a to 41d of the first blocking plate 41 and the flow ports 42a to 42e of the second block plate 42 is indicated by arrows. As shown in the figure, the intake pulsation propagated from the intake single pipes 31 to 34 mainly flows through the flow ports 41a to 41d of the first blocking plate 41 at positions facing the connection ports 31a to 34a. And it distribute | circulates through each circulation port 42a, 42b, 42d, 42e of the 2nd interruption | blocking board 42, and is each transmitted to the suction port 22a direction. In addition, the intake pulsation is propagated through the flow port 41b of the first blocking plate 41 and the flow port 42c of the second blocking plate 42 which are not opposed to the connection ports 31a to 34a. Here, as described above, the flow port 42c of the second blocking plate 42 is located between the flow port 42b and the flow port 42d of the second block plate 42, and therefore, the flow port 42b and the flow port 42d respectively. The intake pulsation propagates mainly from the intake single pipe 32 and the intake single pipe 33 connected to the opposing positions to the flow port 42c. As a result, the intake pulsation generated from the intake single pipes 31 to 34 is sucked into the intake port 22a through the flow ports 41a to 41d of the first blocking plate 41 and the flow ports 42a to 42e of the second blocking plate 42, respectively. Will be propagated. As a result, along with the positions of the circulation ports 41a to 41d of the first blocking plate 41 and the circulation ports 42a to 42e of the second blocking plate 42, the paths of the pulsations to the suction port 22a are also uneven.

  Next, the state of the combination of the first blocking plate 41 and the second blocking plate 42 at the time of low rotation will be described with reference to FIG. 4 and FIG. 5 with a focus on the difference from the case of high rotation described above. . 4 is a cross-sectional view of the surge tank 20 at the time of low rotation, and FIG. 5 is a view of the first blocking plate 41 and the second block at the time of low rotation as viewed from the upper direction of FIG. The relative positions of the plates 42 are shown. As shown in FIG. 4, the first blocking plate 41 at the time of low rotation is disposed so that the right end in the same figure is in contact with the upstream side wall 26 of the surge tank 20. Further, as described above, since both ends of the second blocking plate 42 are fixed to the side walls in the surge tank 20, the positions of the flow ports 42a to 42e are not changed between the high rotation time and the low rotation time. That is, when the first blocking plate 41 is slid, the way in which the flow ports 41a to 41d of the first blocking plate 41 and the flow ports 42a to 42e of the second blocking plate 42 overlap is from the time of high rotation. It has changed.

  Specifically, as shown in FIG. 5, in the combination of the flow ports 41 a to 41 d of the first blocking plate 41 and the flow ports 42 a to 42 e of the second block plate 42, The distribution port 42a, the distribution port 41b and the distribution port 42b, the distribution ports 41c and 42d, and the distribution port 41d and the distribution port 42e do not overlap each other. Thereby, the flow ports 41a, 41c, 41d of the first blocking plate 41 are closed by the second blocking plate 42, and the flow ports 42a, 42b, 42d, 42e of the second blocking plate 42 are closed by the first blocking plate 41. The However, when switching from high rotation to low rotation, the right end portion of the flow port 41b of the first blocking plate 41 in FIG. 5 is shifted from the opening position of the flow port 42c of the second blocking plate 42 in the right direction of the figure. However, the circulation port 41b itself remains in communication with the circulation port 42c. This is because, as described above, the flow port 41b of the first blocking plate 41 is set to a size that can overlap with the flow port 42b and the flow port 42c of the second blocking plate 42.

  Next, how the intake pulsation propagates during low rotation will be described. During low rotation, due to the above-described configuration, the intake pulsation flows only through the flow port 41b of the first blocking plate 41 and the flow port 42c of the second blocking plate 42 as shown by the arrows in FIG. As described above, the circulation port 42c is formed at an intermediate position between the connection port 32a and the connection port 33a. In other words, it can be said that the distribution port 42c is positioned at an intermediate position between the connection port 31a and the connection port 34a. That is, with respect to the distance from the intake ports 36 to 39 (FIG. 1) of each cylinder to the intake port 22a, the above-mentioned distances through the intake single pipe 32 and the intake single pipe 33 are substantially equal. The distances through the single tubes 34 are substantially equal. Accordingly, the intake pulsations generated from the intake single pipe 32 and the intake single pipe 33 are substantially the same, and the intake pulsations generated from the intake single pipe 31 and the intake single pipe 34 are substantially the same. Further, the difference in the distance through the intake single pipe 31 and the single intake pipe 32 and the difference in the distance through the intake single pipe 33 and the single intake pipe 34 are also smaller than at the time of high rotation. As a result, the path difference of the intake air pulsation between the cylinders up to the intake port 22a is reduced.

According to 1st Embodiment described above, there can exist the following effects.
(1) In the first blocking plate 41 and the second blocking plate 42 formed in the surge tank 20, the first blocking plate 41 is slid along the second blocking plate 42 according to the engine speed, and the first The circulation state of the pulsation that circulates through the circulation ports 41a to 41d formed in the blocking plate 41 and the circulation ports 42a to 42e formed in the second blocking plate 42 is variable. Therefore, it is possible to improve the characteristics of the sound generated by the interference of the intake pulsation by making the deviation of the distances from the connection ports 31a to 34a between the intake single pipes 31 to 34 and the surge tank 20 to the intake port 22a variable. it can.

  (2) When the engine speed is high, the flow ports 41a to 41d of the first blocking plate 41 and the flow ports 42a to 42e of the second blocking plate 42 are overlapped to communicate the intake air. Further, the intake pulsation generated from each intake single pipe 31 to 34 is connected to the distribution ports 41a to 41d and the distribution ports set at positions facing the connection ports 31a to 34a between the intake single pipes 31 to 34 and the surge tank 20. It is assumed that the mouths 42a to 42e are distributed. Therefore, by increasing the deviation of the distance from the connection ports 31a to 34a to the intake port 22a with the surge tank 20, an explosion non-integer order component is generated, and a sporty sound intake sound can be created.

  (3) When the engine speed is low, it is assumed that only the flow port 41b of the first blocking plate and the flow port 42c of the second blocking plate 42 overlap, and the intake pulsations generated from the single intake pipes 31 to 34 are the flow ports. It is assumed that 41b and the distribution port 42c are distributed. Therefore, by reducing the deviation of the distance from each connection port 31a to 34a to the intake port 22a with the surge tank 20, the explosion non-integer order component can be reduced, and a smooth intake sound can be created.

(Second Embodiment)
A second embodiment in which an intake system of a multi-cylinder internal combustion engine according to the present invention is embodied in a surge tank of an in-line four-cylinder engine will be described below with reference to FIGS. 6 and 7. In addition, the description is abbreviate | omitted about the location similar to the structure of the intake system of the multicylinder internal combustion engine concerning the above-mentioned 1st Embodiment.

  FIG. 6 shows a perspective view of the surge tank 120 in the present embodiment. As shown in the figure, the surge tank 120 has an upper tank 120a and a lower tank 120b, which have a rectangular outer cross section perpendicular to the longitudinal direction, respectively. Further, the outer peripheral section perpendicular to the longitudinal direction is square by joining the peripheral edge of the upper tank 120a having an opening in the lower part of FIG. 6 and the peripheral part of the lower tank 120b having an opening in the upper part of the figure. A surge tank 120 having a shape is formed. In addition, a cylindrical suction pipe 122 that sucks intake air is connected to a side wall (a square side wall on the right side in the drawing) of the surge tank 120 that is an upstream portion of the intake flow, substantially perpendicularly to the end face. Has been.

Next, the internal structure of the surge tank 120 in this embodiment will be described in detail with reference to FIG.
FIG. 7 shows a cross-sectional view of the surge tank 120 in the present embodiment. As shown in FIG. 7, intake single tubes 31 to 34 are connected to the side wall 125 extending in the longitudinal direction of the surge tank 120 in parallel at substantially equal intervals, and each of the intake single tubes 31 to 34 is connected to each other. The tips 31b to 34b are disposed so as to protrude into the surge tank 120. Further, it is located on the upstream side wall 126 (right side wall in the figure) of the surge tank 120 and is closest to the connection portion of the surge tank 120 and the intake single pipes 31 to 34 on the side wall 125 of the surge tank 120. In addition, a suction pipe 122 is connected, and a suction port 122 a is formed so that the suction pipe 122 and the surge tank 120 communicate with each other. In other words, the longer the protruding length of the intake single pipes 31 to 34 in the surge tank 120, the longer the distance between the tips 31b to 34b of the intake single pipes 31 to 34 and the intake port 122a becomes the same. A mouth 122a is formed.

  Here, in the surge tank 120 according to the present embodiment, the intake single pipes 31 to 34 are protruded from the surge tank 120 (from the connecting portion between the side wall 125 and each intake single pipe 31 to 34. The lengths of the single tubes 31 to 34 to the tips 31b to 34b) become longer as they approach the suction port 122a. Specifically, the intake single pipes 31 to 34 are connected to the wall surface of the side wall 125 of the surge tank 120 at a predetermined angle. This predetermined angle will be described later.

  Next, how the intake pulsation propagates in this embodiment will be described. The arrows in FIG. 7 indicate the paths through which the intake pulsations generated from the intake single pipes 31 to 34 propagate to the intake port 122a. As shown in the figure, in the intake single pipes 31 to 34, for example, the intake pulsation generated from the intake single pipe 31 having the shortest projecting length in the surge tank 120 (the left end in the figure) After propagating from the tip 31 b of 31 into the surge tank 120, it propagates to the inlet 122 a along the side wall 125 of the surge tank 120. As the protrusion length in the surge tank 120 increases from the intake single pipe 31 to the intake single pipe 34, the generated intake pulsation propagates to a position away from the side wall 125 of the surge tank 120. That is, for example, the intake pulsation generated from the intake single pipe 34 having the longest protrusion length in the surge tank 120 is propagated into the surge tank 120 via the tip 34b of the intake single pipe 34 and then the intake single pipe 34. It propagates along the pipe 34 to the inlet 122a. Here, with respect to each distance from each of the tips 31b to 34b of the intake single pipes 31 to 34 to the intake port 122a, the intake single pipes 31 to 34 are connected vertically to the surge tank without being inclined as in the present embodiment in FIG. In the case where the intake single pipes 31 to 34 are protruded to substantially the center of the surge tank 120 (hereinafter referred to as conventional), the distance of the intake single pipe connected to the position farthest from the intake port is the longest. The above-mentioned distance of the single intake pipe connected to the position closest to the suction port is the shortest. Comparing this conventional case with the present embodiment, the distance of the intake single pipe 31 in the present embodiment is shorter than the conventional distance, and the distance of the intake single pipe 34 is longer than the conventional distance. That is, since the difference between the above-mentioned distances of the intake single pipes 31 to 34 between the cylinders is smaller than in the conventional case, the propagation path difference between the intake single pipes 31 to 34 to the intake port 122a. Becomes smaller. Note that the magnitude of the predetermined angle in the present embodiment is set to a value that minimizes the difference in intake pulsation path between cylinders. This value is an experimental value calculated by experiment.

According to 2nd Embodiment demonstrated above, there can exist the following effects.
(4) While the lengths of the single intake pipes 31 to 34 are maintained to be equal, the protruding length of the single intake pipes 31 to 34 in the surge tank 120 is set to a length according to the connection position with respect to the surge tank 120. Each can be set. Accordingly, it is possible to reduce the difference in the propagation path of the intake pulsation between the cylinders and improve the characteristics of the sound generated by the interference of the intake pulsation.

(Third embodiment)
A third embodiment in which an intake system of a multi-cylinder internal combustion engine according to the present invention is embodied in a surge tank of an in-line four-cylinder engine will be described below with reference to FIGS. In addition, the description is abbreviate | omitted about the location similar to the structure of the intake system of the multicylinder internal combustion engine concerning the above-mentioned 1st, 2nd embodiment.

  FIG. 8 shows a cross-sectional view of the surge tank 220 in the present embodiment. As shown in FIG. 8, intake side pipes 31-34 (the cross section is not shown in the figure) are substantially equally spaced on the side wall 225 (upper side wall in the figure) extending in the longitudinal direction of the surge tank 220. Are connected in parallel with each other, and tips 31b to 34b of the intake single pipes 31 to 34 are disposed so as to protrude into the surge tank 220. Here, the length of protrusion of each intake single pipe 31-34 within the surge tank 220 (the length from the side wall 225 to each tip 31b-34b in the figure) is made equal between cylinders. A suction pipe 222 is connected to the upstream side wall 226 of the surge tank 220 (right side wall in the figure) at a position closest to the connection port between the intake single pipes 31 to 34 and the surge tank 220. In addition, a suction port 222 a is formed so that the suction pipe 222 and the surge tank 220 communicate with each other.

  Here, in this embodiment, in addition to the above-described configuration, the surge tank 220 is further provided with a drive mechanism for adjusting the protruding length. This drive mechanism will be described in detail next.

  As shown in FIG. 8, in the surge tank 220, a partition plate 52 whose one end (the left end in the figure) is rotatably supported on the side wall of the surge tank 220 (a cross section is shown in the figure). Is provided. The partition plate 52 is rotated about the end by a motor 51 that is drivingly connected to the end, and the motor 51 is connected to a control device (not shown) via the drive circuit. Note that a crank angle sensor that detects the rotational phase of the crank angle shaft of the internal combustion engine is connected to the control device in the present embodiment, and according to the engine speed (high rotation, low rotation) detected from the crank angle sensor. The motor 51 is operated to control the rotation angle of the partition plate 52. Further, the partition plate 52 has through-holes 52a to 52d formed at substantially equal intervals in the horizontal direction in FIG. The through-holes 52a to 52d have an elliptical shape that is substantially equal to each other, and the size is set to be larger by a predetermined area than the opening surfaces of the tips 31b to 34b of the intake single tubes 31 to 34. This predetermined area will be described later.

Next, how the partition plate 52 rotates will be specifically described.
First, the case where the engine speed is high will be described with reference to FIG. As shown in FIG. 8, at the time of high rotation, the partition plate 52 is disposed so as to be substantially coincident with and parallel to the opening surfaces of the tips 31b to 34b of the single intake pipes 31 to 34. Further, the leading ends 31 b to 34 b of the intake single pipes 31 to 34 are inserted into the through holes 52 a to 52 d of the partition plate 52. As a combination of the through holes 52a to 52d and the tips 31b to 34b, the tip 31b, the tip 32b, the tip 32b, the tip 32b, the tip 32b, the tip 32b, The leading end 34b is inserted through the through hole 52d.

  Next, how the intake pulsation propagates during high rotation will be described. The intake pulsation generated from each intake single pipe 31 to 34 propagates in the right direction in FIG. 8 along the lower surface of the partition plate 52 in FIG. 8 and reaches the intake port 222a. Specifically, for example, the intake pulsation generated from the intake single pipe 31 (the left end in the figure) propagates into the surge tank 220 via the tip 31b of the intake single pipe 31 and the through-hole 52a of the partition plate 52. Thereafter, the intake pulsation advances in the right direction in the figure along the lower surface of the partition plate 52 in the figure. The intake pulsation reaches the end of the partition plate 52 on the upstream side wall 226 side of the surge tank 220 and then propagates to the suction port 222 a of the surge tank 220. Regarding the intake pulsation path, there is almost no pulsation path difference between the cylinders from the right end of the partition plate 52 to the suction port 222a of the surge tank 220, but from the through holes 52a to 52d of the partition plate 52. This occurs with a difference in distance to the right end. For example, the intake single tube 31 inserted through the through hole 52a formed at the position farthest from the right end of the partition plate 52 has a pulsation path to the intake port 222a in the intake single tubes 31 to 34. Longest. On the other hand, the intake single pipe 34 inserted through the through-hole 52d formed at a position closest to the end of the partition plate 52 has the pulsation path to the intake opening 222a most among the intake single pipes 31 to 34. short. Thus, at the time of high rotation, a pulsation path difference occurs between the cylinders with the length of each pulsation path generated from the intake single pipes 31 to 34.

  Instead, the case where the engine speed is low will be described with reference to FIG. The state in the surge tank 220 at the time of low rotation is such that the partition plate 52 has one end (the left end in FIG. 8) in the direction approaching the side wall 225 of the surge tank 220 from the state at the time of high rotation (FIG. 8). FIG. 9 shows a state rotated by a predetermined angle about the center (FIG. 9). As shown in FIG. 9, each intake single pipe 31 to 34 penetrates through each of the through holes 52 a to 52 d of the partition plate 52, and is partitioned from each tip 31 b to 34 b of the intake single pipe 31 to 34. The distance to the portion in contact with the plate 52 is longer as the single intake pipe closer to the suction port 222a among the single intake pipes 31 to 34. Here, the portion of the intake single pipes 31 to 34 that intersects the partition plate 52 indicates a portion that penetrates the through holes 52 a to 52 d formed in the partition plate 52. For example, in the single intake pipe 31 (the left end in the figure) that is farthest from the intake port 222a, the distance from the tip 31b is the shortest, but the single intake pipe 34 that is closest to the intake port 222a (the same figure). The right distance from the tip 34b is the longest. The predetermined angle in the present embodiment will be described later.

  Next, how the intake pulsation propagates during low rotation will be described. The pulsation at the time of low rotation propagates from the intake single pipes 31 to 34 into the surge tank 220 through the tips 31b to 34b, and then travels substantially straight to the intake port 222a without hitting the partition plate 52. That is, at the time of low rotation, the intake pulsation follows the shortest distance from each tip 31b to 34b of each intake single pipe 31 to 34 to the intake port 222a. Here, each path of the intake pulsation generated from each intake single pipe 31-34 at the time of low rotation (FIG. 9) is shorter than each path at the time of high rotation (FIG. 8). . Further, the farther the formation position of the single intake pipes 31 to 34 in which the pulsation occurs is away from the suction port 222a, the shorter the path of the pulsation that occurs than in the high rotation. In other words, the closer the formation position of the intake single pipes 31 to 34 is to the intake port 222a, the smaller the difference between the generated pulsation path and that at the time of high rotation. Accordingly, the path difference between the cylinders at the time of low rotation is smaller than that at the time of high rotation. Note that, as the predetermined area in the present embodiment, when the partition plate 52 is rotated around one end thereof as described above, the through-hole 52a is provided so that the partition plate 52 and the single intake pipes 31 to 34 do not contact each other. An area of ˜52d is set. In addition, the predetermined angle in the present embodiment is a rotation angle of the partition plate 52 in which the path difference of the intake pulsation generated from the intake single pipes 31 to 34 is expected to be sufficiently smaller than that at the time of high rotation. is there. The predetermined area and the predetermined angle are calculated in advance based on experimental values.

According to the third embodiment described above, the following effects can be obtained.
(5) At the time of high rotation, the partition plate 52 is made parallel to the opening surfaces of the tips 31b to 34b of the intake single pipes 31 to 34, and the tips 31b to 34b are inserted into the through holes 52a to 52d of the partition plate 52. I tried to make it. Therefore, an explosion non-integer order component is obtained by increasing the deviation of the intake flow distance from each of the tips 31b to 34b to the intake port 222a of the surge tank 220 while maintaining the lengths of the intake single pipes 31 to 34 at the same length. This creates a sporty tone.

  (6) At the time of low rotation, the partition plate 52 is rotated around one end thereof, and the length from each tip 31b to 34b of the intake single pipes 31 to 34 in the surge tank 220 to the portion in contact with the partition plate 52 The length is made longer as it gets closer to the suction port 222a. Therefore, while maintaining the lengths of the single intake pipes 31 to 34 to be equal, the deviation of the intake flow distance from the protruding tips 31b to 34b of the single intake pipes 31 to 34 to the intake port 222a of the surge tank 220 is changed. By making it small, the explosion non-integer order component can be reduced and a smooth tone can be created.

In addition, the said embodiment can also be implemented with the following forms which changed this suitably.
In the second embodiment, in the upstream side wall 126 of the surge tank 120, the position closest to the connection portion between the surge tank 120 and the intake single pipes 31 to 34 on the side wall 125 of the surge tank 120, In other words, the suction port 122a is formed at a position where the distance between each tip of the suction single tubes 31 to 34 and the suction port 122a becomes longer as the protruding length of the suction single tubes 31 to 34 in the surge tank 120 becomes longer. The configuration to adopt was adopted. However, in the upstream side wall of the surge tank, the position that is farthest from the connection portion between the surge tank and the single intake pipe on the side wall, in other words, the longer the protrusion length in the surge tank of the single intake pipe, The configuration may be such that the suction port is formed at a position where the distance between each tip of the single tube and the suction port is short. Specifically, as shown in FIG. 10, the surge tank having this configuration is located on the upstream side wall 326 (right side in the figure) of the surge tank 320 and on the side wall 325 (upper side in the figure). A suction port 322a is provided at a position farthest from the connection portion between 320 and the single intake pipes 31-34. Further, contrary to the second embodiment, each intake single pipe is arranged such that the protrusion of the intake single pipes 31 to 34 closer to the intake port 322a has a shorter protruding length in the surge tank 320. 31-34 are connected to the surge tank 320 in a state inclined at a predetermined angle. In addition, the protrusion length in this form shows the length of each intake single pipe 31-34 from each front-end | tip 31b-34b to the connection part with this surge tank 320 in the side wall 325 of the surge tank 320. FIG. Further, the magnitude of the predetermined angle in this embodiment is set to such a value that the difference in intake pulsation path between cylinders is as small as possible, and an experimental value derived by experiment is adopted as the value. Also in the surge tank 320 having such a configuration, as indicated by an arrow in FIG. 10, the path difference of the intake pulsation generated from each intake single pipe 31 to 34 becomes small between the cylinders. The same effect as the embodiment can be expected.

  In the third embodiment, the partition plate 52 is rotated in the surge tank 220, but may be moved up and down in the surge tank. Specifically, a screw portion that is controlled according to the engine speed is disposed along the side surface of the surge tank, and a gear portion that meshes with the tooth trace of the screw portion is provided at the end of the partition plate. The partition plate may be supported so as to be vertically movable by meshing between the screw portion and the gear portion.

  In the first embodiment, the first blocking plate 41 is placed on the left side wall in FIG. 2 in the surge tank 20 during high rotation, and the first blocking plate 41 is upstream in the surge tank during low rotation. The first side wall and the second side wall are not necessarily in contact with the side wall of the surge tank.

  In the first embodiment, only the first blocking plate 41 is slid along the second blocking plate 42 whose both ends are fixed in the surge tank 20, but the first blocking plate is reversed. Only the second blocking plate may be moved while being fixed, or both the first blocking plate and the second blocking plate may be moved without fixing the second blocking plate.

  -In the said 1st Embodiment, although the connection ports 31a-34a of the one end of each intake single pipe 31-34 were each formed in the side wall 25 of the surge tank 20 so that it might open in this surge tank 20, Each intake single pipe may protrude into the surge tank and be connected to the surge tank.

  In the first embodiment, the first blocking plate 41 has three through holes 41a to 41d each composed of three holes, and the second blocking plate 42 has three holes each. Although the circulation ports 42a-42e were each formed, the number of the holes which comprise each circulation port is not limited. Further, the positions of the flow ports formed in the first blocking plate and the second blocking plate can be appropriately changed according to the mode of intake pulsation.

  In the first embodiment, the flow ports 41a, 41c, 41d of the first blocking plate 41 are circular with approximately the same size, and only the flow port 41b is elliptical, but the shape is not limited. . In short, it is only necessary that the distribution port 41b has a predetermined length in the first embodiment. Similarly, the shape of the flow ports 42a to 42e of the second blocking plate 42 is not limited to a circle.

  In the first embodiment, the two shielding plates, the first shielding plate 41 and the second shielding plate 42, are arranged in the surge tank 20, but a plurality of other shielding plates are arranged. Also good.

  In the first embodiment, the surge tank 20 has a circular outer cross section as shown in FIG. 1, but it is rectangular even if it is square as shown in FIG. There may be.

  In the third embodiment, the partition plate 52 is formed with the circular through holes 52a to 52d, but the shape is not limited. In short, it is sufficient that the partition plate and the single intake pipe do not come into contact with each other when the partition plate rotates according to the engine speed.

  In the first and third embodiments, the operation of the drive mechanism is controlled in accordance with the engine speed detected from the crank angle sensor. For example, the operation amount of the accelerator pedal of the vehicle is detected. You may control according to the detected value of the sensor which detects the driving | running state of other engines, such as an accelerator sensor.

  In the first to third embodiments, the structure of the surge tank employed in the in-line four-cylinder engine is shown. However, the present invention is not limited to the four-cylinder engine, but other in-line multi-cylinder engines and V-type engines. It can also be adopted.

1 is a perspective view showing a first embodiment in which an intake system of a multi-cylinder internal combustion engine according to the present invention is embodied in a surge tank. Sectional drawing of the surge tank concerning the embodiment. The front view which shows the combination structure of the shielding board arrange | positioned in the surge tank concerning the embodiment. Sectional drawing of the surge tank concerning the embodiment. The front view which shows the combination structure of the shielding board arrange | positioned in the surge tank concerning the embodiment. The perspective view which shows 2nd Embodiment which actualized the intake system of the multicylinder internal combustion engine concerning this invention to the surge tank. Sectional drawing of the surge tank concerning the embodiment. Sectional drawing which shows 3rd Embodiment which actualized the intake system of the multicylinder internal combustion engine concerning this invention to the surge tank. Sectional drawing of the surge tank concerning the embodiment. Sectional drawing which shows the modification of the surge tank structure concerning this invention.

Explanation of symbols

  20, 120, 220, 320 ... surge tank, 20a, 120a, 220a, 320a ... upper tank, 20b, 120b, 220b, 320b ... lower tank, 22, 122, 222, 322 ... suction pipe, 22a, 122a, 222a, 322a ... suction port, 25, 125, 225, 325 ... side wall, 26, 126, 226, 326 ... upstream side wall, 31, 32, 33, 34 ... single intake pipe, 31a, 32a, 33a, 34a ... connection port, 31b, 32b, 33b, 34b ... tip, 35 ... intake port plate, 36, 37, 38, 39 ... intake port, 36a, 37a, 38a, 39a ... connection port, 41 ... first blocking plate, 41a, 41b, 41c , 41d ... distribution port, 42 ... second blocking plate, 42a, 42b, 42c, 42d, 42e ... distribution port, 51 ... motor, 52 ... partition plate 52a, 52b, 52c, 52d ... through hole.

Claims (6)

An equal-length intake manifold that communicates each cylinder of the multi-cylinder internal combustion engine and the surge tank is arranged in parallel, and a suction port common to each cylinder that sucks intake air is formed on the side wall of the upstream portion of the surge tank, In the intake system structure of the multi-cylinder internal combustion engine in which the connection ports of the manifold and the surge tank are sequentially arranged on the downstream side,
A plurality of blocking plates arranged in the surge tank and formed with circulation ports through which intake air can be circulated, and each of the connection ports by changing the flow state of the circulation ports by relatively moving the plurality of blocking plates An intake system structure for a multi-cylinder internal combustion engine, comprising: a drive mechanism that varies a deviation in distance from the intake port to the intake port. In claim 1,
In the multi-cylinder internal combustion engine, the plurality of blocking plates are formed to be substantially equal in size and arranged in parallel to each other, and the formation positions of the flow ports in the plurality of blocking plates are different for each blocking plate. Intake system structure. An equal-length intake manifold that communicates each cylinder of the multi-cylinder internal combustion engine and the surge tank is arranged in parallel, and an intake port common to each cylinder that supplies intake air to the upstream side wall of the surge tank is formed, In the intake system structure of the multi-cylinder internal combustion engine in which the connection ports of the manifold and the surge tank are sequentially arranged on the downstream side,
The suction port is formed at a position where the distance between each tip of the manifold and the suction port becomes longer as the protruding length of the manifold in the surge tank becomes longer, and the manifold has the suction port. An intake system structure for a multi-cylinder internal combustion engine, wherein the intake system structure is inclined at a predetermined angle with respect to the wall surface of the surge tank so that the protruding length in the surge tank becomes longer as the distance from the tank increases. An equal-length intake manifold that communicates each cylinder of the multi-cylinder internal combustion engine and the surge tank is arranged in parallel, and an intake port common to each cylinder that supplies intake air to the upstream side wall of the surge tank is formed, In the intake system structure of the multi-cylinder internal combustion engine in which the connection ports of the manifold and the surge tank are sequentially arranged on the downstream side,
The suction port is formed at a position where the distance between each tip of the manifold and the suction port becomes shorter as the protruding length of the manifold in the surge tank becomes longer, and the manifold has the suction port. An intake system structure for a multi-cylinder internal combustion engine characterized by being connected at a predetermined angle with respect to the wall surface of the surge tank so that the protruding length in the surge tank becomes shorter as the distance from An equal-length intake manifold that communicates each cylinder of the multi-cylinder internal combustion engine and the surge tank is arranged in parallel, and an intake port common to each cylinder that supplies intake air to the upstream side wall of the surge tank is formed, In the intake system structure of the multi-cylinder internal combustion engine in which the connection ports of the manifold and the surge tank are sequentially arranged on the downstream side,
The manifold protrudes into the surge tank;
A partition plate for adjusting the protruding length of the manifold in the intake circulation portion in the surge tank, and the protruding length of the manifold is adjusted by moving the partition plate relative to the manifold. An intake system structure for a multi-cylinder internal combustion engine, comprising: a drive mechanism that varies a deviation of an intake flow distance from each tip to the intake port. In claim 5,
The partition plate is pivotally supported in the surge tank so as to be rotatable around one end,
The intake mechanism of the multi-cylinder internal combustion engine, wherein the drive mechanism is adjusted such that each distance from each protruding tip of the manifold to a portion intersecting the partition plate becomes longer as the distance to the intake port increases Construction.

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