JPH10274103A - Intake device for engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an intake device for an engine having an EGR device to sufficiently provide the damping function of an intake system and besides favorable in terms of a cost and weight, in the intake device structure of a multicylinder engine. SOLUTION: An intake device for an engine is formed in such a way that intake pipes 6, 7, 8, and 9 being independent from each other are integrally intercoupled by an EGR pipe 13 situated upper stream from an EGR valve 16, and parts of EGR pipes 13 and 17 are integrally arranged along the wall surface of the independent intake pipe 6 positioned nearest the support part of a throttle body 14. This constitution forms a format to reinforce the throttle body support structure of a surge tank and improves the damping strength of the periphery of an intake manifold 2 containing an intake system, especially a throttle body 4, without needing special reinforcing structure and thus by a method being favorable in terms of weight and a cost.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake system for a multi-cylinder engine, and more particularly to an intake system for an engine having an EGR mechanism and having a plurality of independent intake pipes branching from a common space and communicating with respective cylinders. About.

[0002]

2. Description of the Related Art A strong vibrating force is applied to an engine of a vehicle by the vibration of the vehicle while the vehicle is running or by the operation of the engine itself. Accordingly, the intake system and the exhaust system around the engine are also exposed to severe vibration conditions. From the viewpoint of vehicle durability, noise, and the like, the structure for suppressing the vibration of the peripheral devices and devices of such an engine must be sufficiently considered in terms of weight, cost, layout, and the like. In particular, in the intake system of a multi-cylinder engine, since a heavy throttle body is disposed in front of the surge tank, the support strength of the throttle body also becomes a problem.

Further, a multi-cylinder engine equipped with an EGR device is well known. In such a multi-cylinder engine with an EGR device, how to incorporate the EGR device into an engine intake system under severe layout conditions is a problem. Becomes In this case, for example, as disclosed in Japanese Patent Application Laid-Open No. 6-108928, EGs are respectively connected to independent intake pipes communicating with the cylinders.
In the method in which the R inlet is provided, good distribution of the EGR gas can be ensured, but there is a problem that the structure of the EGR device is complicated. Therefore, a relatively simple EGR
In order to maintain the device structure and good distribution, it is desirable to provide an EGR inlet in the surge tank upstream of the independent intake pipe. However, as described above, not only the layout conditions are extremely strict around the engine, but also as described above, while fully exhibiting the vibration damping function of heavy objects,
There are various problems in providing an EGR device that performs a desired function in an intake system of a multi-cylinder engine.

[0004]

SUMMARY OF THE INVENTION The present invention has been developed from the above-mentioned viewpoints, and has been developed for an intake system to which a heavy object such as a throttle body is attached in an intake system structure of a multi-cylinder engine having an independent intake pipe. It is an object of the present invention to provide an intake device for an engine having an EGR device that can sufficiently exhibit a vibration damping function and is advantageous in terms of cost and weight.

[0005]

To achieve the above object, the present invention has the following features. An intake system for an engine according to the present invention includes: a plurality of independent intake pipes extending substantially in parallel with each other and communicating with respective intake ports formed in a plurality of cylinders arranged side by side; A common space portion common to the cylinders having an internal space extending in the cylinder row direction, wherein the upstream ends of the tubes are gathered, and an EGR tube formed with an EGR passage for introducing EGR gas into the common space portion is provided. In the intake system of the engine,
The EGR pipe is connected to the plurality of independent intake pipes and extends substantially parallel to the cylinder row direction, and is formed integrally with the independent intake pipes.

In a preferred aspect, the portion of the EGR pipe connecting the independent intake pipe is an EGR pipe upstream of the EGR valve which constitutes an EGR passage between the EGR valve and an EGR gas extracting portion from the exhaust system. . In addition, the EGR
It is preferable that a part of the pipe extends along an upstream independent intake pipe connected to the most upstream side of the common space and is formed integrally with the independent intake pipe. Further preferably, when the engine is mounted, the EGR valve upstream EGR pipe and the independent intake pipe are integrally formed so that the EGR passage is located below the independent intake pipe. In another preferred aspect, a connecting member that connects the common space portion and a connection end of the independent intake pipe to the cylinder head is provided at least with the upstream independent intake pipe connected to the most upstream side of the common space portion. It is provided between the space part.

In the above case, it is preferable that the EGR valve mounting boss is provided at a portion of the EGR pipe extending along the upstream independent intake pipe connected to the most upstream side of the common space. When the engine is mounted, each of the independent intake pipes branched from the common space portion extends downward while being curved, and then extends substantially horizontally to be connected to a cylinder head of the engine. The pipe preferably extends near the lowest point of the curved independent intake pipe by connecting the independent intake pipes along the cylinder row direction. In this case, the independent intake pipe branches downward from the common space, extends downward while bending, and then extends substantially horizontally, slightly upward while maintaining the curved state, and is then connected to the cylinder head of the engine. Preferably, the EGR pipe is integrally formed by connecting the lower sides of the independent intake pipes at a position slightly raised from the lowest point of the independent intake pipe.

According to another feature of the present invention, a plurality of the common spaces are provided, that is, at least another common space is provided, and these common spaces are connected to the operating state of the engine. , So that the output torque performance curve of the engine is as high as possible and the torque fluctuation accompanying the change in the engine speed does not become unduly large. In this case, at least a part of the communication path connecting the plurality of common space portions is
It is formed integrally with the EGR. Rigidity is achieved while suppressing weight increase. Preferably, on at least one side with respect to the longitudinal direction of the common space portion, the communication passage is formed to protrude from the common space portion. In this case, an EGR valve is disposed on the other side of the common space where the communication passage does not protrude in the longitudinal direction.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The engine to which the present invention is applied is as follows.
A multi-cylinder engine in which a plurality of cylinders are arranged side by side,
Independent intake pipes are respectively provided for a plurality of cylinders of the engine. The upstream side of the intake system is one common to each cylinder.
A surge tank having a constant volume, that is, a common space portion is provided at a downstream end of the common intake passage, and an independent intake pipe is formed by branching downstream of the surge tank. And the independent intake pipe constitute an intake manifold. The independent intake pipes are separated from each other and connected to the intake ports of each cylinder. On the other hand, a relatively heavy throttle body is mounted upstream of the surge tank. The engine to which the present invention is suitably applied is EG
An in-line multi-cylinder engine has a structure in which a heavy throttle body is attached to an upstream end of a surge tank of an intake manifold of an in-line multi-cylinder engine. In such a configuration, the support structure of the throttle body is provided by the intake pipe. However, since the independent intake pipes are respectively attached to the engine in a separated state, the throttle pipe is used for engine vibration or other vibration. The problem is the strength of the support of the body.

In particular, since the throttle body is attached to the upstream end of a surge tank extending in the direction of the cylinders in an offset state from the center of the engine, an intake based on the vibration of the throttle body relative to a portion where the intake manifold and the engine are attached. The torsional rigidity of the manifold becomes a problem. According to the present invention, in order to cope with such a problem of rigidity of the intake manifold, an EGR pipe is formed by connecting the plurality of independent intake pipes substantially parallel to the cylinder row direction and extending and integrally formed with the independent intake pipe. It is. As described above, in general, the independent intake pipes of the intake manifold connected to the cylinder in the separated state are connected to each other by the EGR pipe, so that the strength of the intake manifold is improved. The vibration can be effectively suppressed to within an allowable range without taking reinforcement measures such as providing ribs. That is, the EGR pipe integrated with the independent intake pipe of the present invention provides a reinforced structure for supporting the throttle body.

As described above, in a preferred embodiment, the portion of the EGR pipe connecting the independent intake pipe is provided between the EGR valve and the EGR gas take-out portion from the exhaust system.
Since it is the EGR pipe upstream of the EGR valve that constitutes the R passage, the length from the EGR take-out portion to the EGR introduction portion can be set relatively long, and an EGR cooling effect can be provided. In addition, a part of the EGR pipe extends along the independent intake pipe closest to the common space and is formed integrally with the independent intake pipe, whereby the structure near the throttle body can be further strengthened. In this case, in the present invention, since the EGR device is a necessary device from the beginning, it does not cause an increase in parts and an increase in weight. If necessary, a connecting member may be provided to connect the common space portion and a connection end of the independent intake pipe to the cylinder head to secure vibration damping strength.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. A first embodiment of the present invention will be described with reference to FIGS. Referring to FIGS. 1 to 4 as appropriate, the engine to which the present invention is applied is an in-line four-cylinder engine 1, which includes an intake system having an intake manifold 2 and an exhaust pipe 3. At the upstream end of the intake manifold 2, a throttle valve (not shown)
The installed throttle body is attached. The space on the downstream side of the portion where the throttle body 4 of the intake manifold 2 is attached is a common space, that is, a surge tank 5 extending in the cylinder row direction, and the cylinders extend from the surge tank in a direction perpendicular to the extending direction. , Four independent intake pipes 6, 7, 8, 9 are branched. The independent intake pipes 6, 7, 8, and 9 extend from the surge tank 5 while bending downward, extend slightly upward from the lowermost end, and further extend substantially in the horizontal direction.
Is connected to the intake port of each cylinder. Above the engine, attached devices and devices such as a fuel injection device 11 and an ignition device 12 are attached. An EGR pipe 13 for guiding EGR gas from the exhaust system to the intake system extends from the exhaust pipe. The EGR pipe 13 is connected to a mounting flange 14 formed at a lower end of an independent intake pipe at one end of the engine. The EGR pipe then extends across the lowermost end of the independent intake pipe in the cylinder row direction and extends below the independent intake pipe at the other end of the engine. in this case,
The independent intake pipe and the EGR pipe of the intake manifold are integrated with each other. Therefore, the EGR pipe 13 not only constitutes a part of an EGR passage for introducing EGR gas from the exhaust system into the intake system, but also forms an intake passage. It serves as a connecting member or reinforcing rib for integrally connecting the independent intake pipes 6, 7, 8, 9 of the manifold 2 to each other.

The EGR pipe 13 is bent downward in a direction away from the cylinder head 10 of the engine 1, that is, outwardly, at a lower portion of the independent intake pipe 6, which is the most upstream of the surge tank 5. Along with it. Another flange 15 is attached to the end of the EGR pipe 13, and an EGR valve 16 for controlling the introduction of EGR gas into the intake system is attached to this flange. E downstream from the EGR valve
The GR pipe 17 further extends integrally and obliquely upward along the wall surface of the independent intake pipe located on the most upstream side of the surge tank, and then extends almost straight upward, and then extends almost straight upward, so that the surge tank 5 immediately downstream of the throttle valve is provided. The EGR gas is introduced into the intake system from the inlet 18. As described above, in the configuration of the present example, each of the independent intake pipes 6, 7, 8, 9 is
The EGR pipe 13 upstream of the valve 16 is integrally connected to each other, and the EG extends along the wall surface of the independent intake pipe 6 closest to the throttle body 14 support portion.
Since a part of the R tubes 13 and 17 are provided integrally,
It is designed to reinforce the throttle body support structure of the surge tank, so that no special reinforcement structure is required, and therefore, the throttle body 4 of the intake system, particularly the throttle body 4, is advantageous in terms of weight and cost. The vibration damping strength of the intake structure around the intake manifold 2 can be increased.

Further, in the present invention, the independent intake pipes 6, 7,
Two connection members 19 are provided in the direction in which the surge tank 5 extends in the direction in which the surge tank 5 extends, in the vicinity of the connection portions 8 and 9 to the cylinder head and the surge tank. Thereby, the rigidity of the intake manifold itself can be further improved. Next, a second embodiment of the present invention will be described with reference to FIGS. The same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. The engine 1 of the present embodiment differs from the previous example in that the engine 1 includes an intake system having a resonance chamber and capable of performing variable intake control. That is, the common space of the surge tank 5 of the engine of the present embodiment is divided into two, a low-rotation resonance chamber 51 and a high-rotation resonance chamber 52, and each of the common spaces has a separate one of the independent intake pipes 6 to 9. The intake passages 61 and 62 (only one is shown) communicate with each other. Further, the intake manifold of this example is divided into two parts, a surge tank side and an independent intake pipe side, and is molded. Both parts are assembled by being bolted together.

As shown in FIGS. 10 and 11, the common spaces 51 and 52 are communicated by a communication passage 20 having a predetermined length. The length, size, and the like of the communication path 20 are determined by how the output characteristics of the engine are set. When performing variable intake control,
It is determined so as to have a predetermined output characteristic. In addition, a shutter valve for functioning a high rotation resonance chamber for obtaining a resonance effect at a high rotation position in the case of supercharging resonance is provided with a high rotation rotation chamber as shown in FIGS. In the passages 62 to 92 communicating with the resonance chamber, shutter valves 22, 23, 24 having a common operating shaft 21 for opening and closing the passages are provided.
25 are provided. In the present example, the EGR pipe 13,
Numeral 17 is disposed inside the curved portions of the independent intake pipes 6 to 9 of the intake manifold 2 and extends across the inside of the curved sections of the independent intake pipes 6 to 9 to connect the independent intake pipes 6 to 9 to each other. I have.

Further, as shown in FIGS. 11 and 12, there is provided a communication passage 26 which communicates the resonance chambers for high rotation with each other and finally communicates with the communication passage 20. The first cylinder extends to the outside of the tank and extends in the cylinder row direction, and communicates the first cylinder and the high-speed resonance chamber 52 of the third cylinder.
Further, in the structure of this example, the throttle body 4 and the actuator 27 of the shutter valves 22 to 25 are arranged on the upstream end side of the surge tank in the cylinder row direction.
An EGR valve 16 is arranged on the other end side.
That is, unlike the previous example, the EGR valve 16 is disposed upstream of the EGR pipe connecting the independent intake pipe with respect to the EGR passage. The layout is designed to avoid interference between the EGR valve 16 and the shutter valve actuator 27. Further, in this example, the intake negative pressure is used to operate the shutter valve actuator 27. However, this negative pressure chamber 28 is used by utilizing the space surrounded by the curved portions of the independent intake pipes 6 to 9. Make up. As shown in FIGS. 8 and 14, in this example, a negative pressure chamber is formed by utilizing a space between the independent intake pipes of the second and third cylinders from the surge tank upstream in the cylinder arrangement direction. An EGR pipe is located above the negative pressure chamber. Therefore, the use of these independent intake pipes and EGR pipes as part of the wall of the negative pressure chamber 28 can save material by connecting them, and can promote integration of the intake manifold and increase rigidity. Can be enhanced.

It is needless to say that a plurality of negative pressure chambers can be provided. In this case, the rigidity of the intake manifold can be further increased, and the vibration damping strength around the engine can be improved.

[0018]

As described above, since the intake manifold is connected by using the EGR pipe, a special material is used around the engine, which is a heavy object attached especially to the upstream side of the intake manifold. The support rigidity of a certain throttle body can be increased, and the vibration damping effect can be effectively improved. According to this configuration of the present invention, the weight is not increased, and the number of parts and the number of steps are not increased, which is advantageous in cost.

[Brief description of the drawings]

FIG. 1 is an external view of an area around an intake manifold of a multi-cylinder engine according to an embodiment of the present invention;

FIG. 2 is a side view of a multi-cylinder engine according to one embodiment of the present invention;

FIG. 3 is a side view of the intake manifold of FIG. 1;

FIG. 4 is a plan view of the intake manifold of FIG. 1;

FIG. 5 is a view similar to that of the first embodiment, showing an intake manifold of a multi-cylinder engine according to a second embodiment of the present invention;

FIG. 6 is a view similar to FIG. 2 according to a second embodiment of the present invention,

FIG. 7 is a cross-sectional view of the independent intake pipe section of the intake manifold according to the second embodiment of the present invention, taken along the line AA in FIG. 8;

8 is a plan view of an independent intake pipe portion of the intake manifold shown in FIG. 7,

FIG. 9 is a view showing a shutter valve arranged in an independent intake pipe;

FIG. 10 is a front view showing a surge tank portion of the intake manifold;

FIG. 11 is a plan view of a surge tank portion of the intake manifold;

FIG. 12 is a plan view of an independent intake pipe unit combined with the surge tank unit of FIGS. 10 and 11;

FIG. 13 is a side view showing a projecting portion of the independent intake pipe portion of FIG. 12 from a mating surface;

FIG. 14 is a side view of an independent intake pipe portion of the intake manifold shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine 2 Intake manifold 3 Exhaust pipe 4 Throttle body 5 Surge tank 6, 7, 8, 9 Independent intake pipe 10 Cylinder head 13 EGR pipe 16 EGR valve 17 EGR pipe 19 Connecting member 20 Communication path 21 Operating member 22, 23, 24 , 25 shutter valve 26 communication path 27 actuator.

Claims (10)

[Claims] A plurality of independent intake pipes extending substantially in parallel with each other and communicating with respective intake ports formed in a plurality of cylinders arranged side by side, and an upstream end of each of the plurality of independent intake pipes. An intake system for an engine, comprising: a common space portion common to the cylinders having an internal space extending in the cylinder row direction and being assembled together; and an EGR pipe having an EGR passage for introducing EGR gas into the common space portion. An intake device for an engine, wherein the EGR pipe extends by connecting the plurality of independent intake pipes substantially in parallel with the cylinder row direction and is formed integrally with the independent intake pipe. 2. A part of the EGR pipe connecting the independent intake pipe is an EGR valve upstream EGR pipe constituting an EGR passage between an EGR valve and an EGR gas take-out part from an exhaust system. The intake device for an engine according to claim 1, wherein 3. A part of the EGR pipe extends along an upstream independent intake pipe connected to the most upstream side of the common space and is integrally formed with the independent intake pipe. The intake device for an engine according to claim 2. 4. The EGR valve upstream EGR pipe and the independent intake pipe are integrally formed such that the EGR passage is located below the independent intake pipe when the engine is mounted. Engine intake system. 5. A connecting member for connecting the common space portion and a connection end of the independent intake pipe to a cylinder head, wherein at least an upstream independent intake pipe connected to the most upstream side of the common space portion and the common space. The intake device for an engine according to any one of the preceding claims, wherein the intake device is provided between the first and second parts. 6. The EGR valve mounting boss portion is provided on a portion of the EGR pipe extending along an upstream independent intake pipe connected to the most upstream side of the common space. Engine intake system. 7. In an engine mounted state, each independent intake pipe branched from the common space portion extends downward while being curved, and then extends substantially horizontally to be connected to a cylinder head of the engine. 5. The engine according to claim 4, wherein the EGR pipe extends near the lowest point of the curved independent intake pipe by connecting the independent intake pipes along the cylinder row direction. Intake device. 8. A method according to claim 1, wherein a plurality of said common spaces are provided, and a communication passage communicating said plurality of common spaces is formed, and at least a part of said communication passage is formed integrally with said EGR. The intake device for an engine according to claim 1, wherein: 9. The intake device for an engine according to claim 9, wherein the communication passage is formed so as to protrude from the common space portion on at least one side in a longitudinal direction of the common space portion. 10. An intake system for an engine according to claim 9, wherein an EGR valve is disposed on the other side of the common space portion where the communication passage does not protrude in the longitudinal direction.