JPH01257717A - Exhaust manifold for five cylinder engine - Google Patents

Abstract

PURPOSE:To increase an output by connecting one part of two cylinders ignited in continuation of the three cylinders connected to a 1st collecting pipe by sliding it to the intermediate part of the 1st collecting pipe. CONSTITUTION:One part #1 of two cylinders #1, 3 ignited continuously of the three cylinders #1, 3, 4 connected to a 1st collecting pipe D1 is connected by sliding to the intermediate part A of the 1st collecting pipe D1. Since the single pipes S1, S3 extended from two cylinders #1, 3 easy to generate an exhaust interference are slipped the reduction in the volumetric efficiency due to the exhaust interference is prevented. The output can thus be increased.

Description

Detailed Description of the Invention A0 Object of the Invention (1) Industrial Application Field The present invention relates to an exhaust manifold for collecting exhaust gas from each cylinder of a 5-cylinder engine and guiding it to a nitrogen sheath pipe. The present invention relates to an exhaust manifold for a five-cylinder engine to prevent a decrease in output due to interference.

(2) Conventional technology The cylinder block of a multi-cylinder engine is connected to an exhaust manifold that collects exhaust gas from each cylinder and guides it to the exhaust pipe. Various forms are used accordingly.

An inline 5-cylinder engine has 5 cylinders #1 to #5 from one end.
It has 3 cylinders, and its ignition is #1 → #2 → #
It is set to take place in the order of 4→#5-#3.

5a and 5b show conventional exhaust manipole l"M used in the above-mentioned five-cylinder engine, and the example in FIG. The single pipes 81 to S5 are connected to the flange 2.
Ti (collected in one tree at one position, and this joint flange 2 is connected to an exhaust pipe 4ζ having a muffler 3. In addition, in the example of Fig. 5b, the pipe extending from the cylinder to the joint flange 2 For single pipe S1, #2 to #
This is a combination of single pipes S2-35 extending from five cylinders. These exhaust manifold l”M is 5
Since the single pipes 31 to S5 are assembled into one pipe in front of the joining flange 2, it is called a 5-1 collection type.

The example in FIG. 6a is #], #3. The three single pipes Sl, S3, and 34 extending from the #4 cylinder are combined into the first collecting pipe D1 in the middle, and the #2. Two single tubes S2 extending from the #5 cylinder. S5 are combined into a second collecting pipe D2 in the middle, and these two collecting pipes D1 and D2 are connected to a joining flange 2.
It is connected to. Also, the example in FIG. 6b is #1.
#2゜#5 cylinder single tube SL, S2. S5 are combined into the first collecting pipe D1 in the middle, and #3. Two single tubes S3 extending from the #4 cylinder. S4 are combined into a second collecting pipe D2 in the middle, and these two collecting pipes D1 and D2 are connected to a joining flange 2. These exhaust manifolds M have five single pipes 31 to S5 in the middle and two
Book collection pipe DI.

It is called a 5-2 set type because it is gathered into D2 and then connected to the joining flange 2.

The example in FIG. 7 is #2. Two single tubes S2 extending from the #5 cylinder. S5 is collected into the first collecting pipe Dl in the middle, and #3. The two single pipes 33 and 34 extending from the #4 cylinder were combined into a second collecting pipe D2 in the middle, and these two collecting pipes D1 and D2 and the single pipe S1 extending from the #1 cylinder were connected to the joint flange 2. It is something. This exhaust manifold M has five single pipes 81.
Since ~S5 are grouped into three trees and connected to the joint flange 2, it is called a 5-3 set type.

(3) Problems to be Solved by the Invention In general, in internal combustion engines, considerable pressure fluctuations occur in the exhaust pipe as the exhaust is blown out, so this pressure fluctuation is used to draw air into the cylinder. Measures are being taken to promote this.

Figure 8 shows the exhaust pipe internal pressure Peχ with respect to the crank angle θ°.
This shows the fluctuation of As is clear from the figure, the exhaust pipe internal pressure which reached the maximum immediately after the bottom dead center BDC becomes the minimum near the top dead center TDC, and in this region where the exhaust pipe internal pressure is small, the opening period E of the exhaust valve and the intake valve A so-called valve weight period O is set in which the opening periods I of the valves overlap. During this valve weight period, the low pressure inside the exhaust pipe propagates into the cylinder to promote intake and improve volumetric efficiency.

Figure 9 shows the exhaust pipe internal pressure PPexo during the valve weight period.
As is clear from the figure, it is understood that the smaller the exhaust pipe internal pressure during the valve weight period, the more the volumetric efficiency improves.

By the way, in a multi-cylinder engine, the intake and exhaust action of a certain cylinder may be significantly inhibited by the exhaust blowing of other cylinders. In other words, during the valve weight period of a certain cylinder, the positive pressure wave of the exhaust blowing of another cylinder is It propagates through the manifold, which increases the pressure in the exhaust pipe during the valve weight period when the pressure should be low, reducing volumetric efficiency. Exhaust interference as described above is particularly likely to occur between two cylinders where the ignition order is consecutive and the length of the interconnecting exhaust manifold is short.

As is clear from the above explanation, the conventional 5-1 collective exhaust manifolds shown in Figures 5a and 5b both have the advantage of being simple and lightweight in structure, but This has the disadvantage that exhaust interference occurs.

Furthermore, if the conventional 5-2 exhaust manifold shown in Figures 6a and 6b is used, most exhaust interference between cylinders is prevented, but the ignition order is continuous and the exhaust gases are connected to each other. Two cylinders with short manifold lengths, namely #1 in FIG. 6a. #3 cylinder,
#1 in the 6th b1g. There is a problem that exhaust interference occurs between the #2 cylinders.

Furthermore, the conventional 5-3 exhaust manifold shown in Fig. 7 has the advantage of preventing exhaust interference between all cylinders, but it requires three pipes to be connected to the joint flange. Therefore, there are problems in that the structure is complicated and the weight increases.

The present invention was made in view of the above-mentioned circumstances, and is an exhaust gas that can prevent exhaust interference between all cylinders in a 5-cylinder engine, has a simple structure around the joining flange, and can be lightweight. The purpose is to provide manifolds.

B1 Structure of the Invention (1) Means for Solving the Problems In order to solve the above-mentioned object, the present invention provides a method for solving the problems by using any three cylinders among the five cylinders arranged in one direction in the cylinder block. The three single pipes extending from the cylinder =9= are combined into the first collecting pipe, and the remaining two
The two single pipes extending from the respective cylinders are combined into a second collecting pipe, and these two single pipes extending from the first and second collecting pipes are combined into a second collecting pipe. In an exhaust manifold for a five-cylinder engine in which a second collecting pipe is connected to a joint flange, one of the two single pipes extending from two cylinders that are ignited consecutively among the three cylinders is connected to the second collecting pipe. The first feature is that the connection is shifted to the middle part of one collecting pipe.

In addition to the above features, the present invention also provides the following features: The second collecting pipes are combined into a third collecting pipe in front of the joining flange, and the connecting part of the staggered connected single pipes to the middle part of the first collecting pipe, and the second collecting pipe of the two single pipes. the connection part of the third
The second feature is that they are located at different distances from the collecting pipe.

(2) Effect According to the first feature of the present invention, the three
The firing order of two of the cylinders is consecutive;
Moreover, since the single pipes extending from both cylinders are connected to a common first collecting pipe, exhaust interference is likely to occur, but one of the single pipes extending from these two cylinders is connected to the first collecting pipe. By being connected in a staggered position in the middle of the cylinder, there is attenuation and a time delay when the heavy pressure wave caused by the exhaust air blowing from the cylinder that is fired later propagates to the cylinder that is fired earlier, and the valve weight period of this cylinder is This prevents the pressure inside the exhaust pipe from increasing.

Moreover, according to the second feature, the first. Since the second collecting pipe is combined into the third collecting pipe at a position in front of the joint flange, in addition to the exhaust interference of the two cylinders mentioned above, the cylinder having the single pipe connected in a staggered manner, and this cylinder and continuous ignition A new problem of exhaust interference arises in one of the two related cylinders on the second collecting pipe side. However, the connecting portion of the staggered connected single pipes to the intermediate portion of the first collecting pipe and the connecting portion of the two single pipes to the second collecting pipe are located at different distances from the third collecting pipe. This causes attenuation and a time delay when the positive pressure wave caused by the exhaust air blowing from the cylinder that is ignited later propagates to the cylinder that is ignited first, and prevents the pressure in the exhaust pipe from increasing during the valve weight period of this cylinder. Ru.

(3) Embodiments Hereinafter, embodiments of the exhaust manifold for a five-cylinder engine according to the present invention will be described based on the drawings.

FIG. 1 shows a first embodiment of the present invention, which is an improved version of the conventional 5-2 exhaust manifold shown in FIG. 6a.

As shown in the first episode, among the five cylinders #1 to #5 arranged in series on the cylinder bronck 1, #3. The two single pipes S3 and S4 extending from the #4 cylinder are combined into a first collecting pipe 1) 1 in the middle, and the #2. Two single tubes S2 extending from the #5 cylinder. S5 are combined into a second collecting pipe D2 in the middle, and these two collecting pipes are connected to the joining flange 2. The single pipe S1 extending from the remaining #1 cylinder is connected to the intermediate part of the first collecting pipe D1,
The connection part A is the above-mentioned #3. Two single tubes S3 extending from the #4 cylinder. It is located as far away as possible from the connection part B of S4. The joining flange 2 is connected to a nitrogen seat pipe 4 having a muffler 3 in the middle,
It is designed to guide exhaust gas to the outside.

Next, the operation of the first embodiment of the exhaust manifold for a five-cylinder engine according to the present invention having the above-described configuration will be described.

FIG. 2 is a diagram showing fluctuations in the exhaust pipe internal pressure Pex at point P of the single pipe S3 of the #3 cylinder, which is subject to exhaust interference due to the exhaust air blowing from the #1 cylinder in FIG. The dashed-dotted line A in the same figure indicates the pressure inside the exhaust pipe due to the connection of the single pipe S1 of the conventional #1 cylinder (L=O; that is, the conventional example in Figure 6a), which is also shown by the dashed-dotted line in Figure 1. This shows that there is significant exhaust interference due to the high peak value of the exhaust pipe internal pressure Pexo during the valve weight period.

A solid line B in FIG. 2 indicates that the connecting portion of the #1 cylinder's single pipe S1 to the first collecting pipe D1 is connected by a distance L.
= L This shows the case where the valve is displaced by L, and the peak value of the exhaust pipe internal pressure Pexo during the valve weight period decreases,
Furthermore, it is understood that exhaust interference is reduced due to the delay in the peak position.

Moreover, the broken line C in FIG. 2 shows the case where the distance 1 is set to L2 which is larger than L1, and the peak value of the exhaust pipe internal pressure Pexo during the valve weight period decreases by -14,-.
− The delay in the peak position becomes even more noticeable as the peak position decreases, indicating that an even greater effect was obtained.

FIG. 3 shows a modification of the embodiment shown in FIG. 1. Instead of connecting the single pipe S1 of the #1 cylinder to the middle of the first collecting pipe DI, a single pipe S3 is connected to the #3 cylinder in the first collecting pipe. It is connected to the middle of the pipe D1. Even with this configuration, #1
It is clear that there is no substantial difference in the relative connection relationship between the single pipe S1 of the cylinder and the single pipe S3 of the #3 cylinder, and that the same effect as that in FIG. 1 can be obtained.

FIG. 4 shows a second embodiment of the present invention, which is a further improved modification of the first embodiment of the present invention shown in FIG.
-1 collective type exhaust manifold is shown.

That is, this exhaust manifold M is the first exhaust manifold M in the modification of the previous embodiment. Second collecting pipe D1. D2 are combined into a third collecting pipe D3 at a position in front of the joining flange 2, and the connecting portion between the joining flange 2 and the collecting pipe is simplified. In this 5-2-1 collective exhaust manifold, the above-mentioned #l.

In addition to the exhaust interference of #3 cylinder, #5. #3 cylinder exhaust interference problem occurs. For this reason, in this embodiment, the connecting part A of the single pipe S3 extending from the #3 cylinder to the intermediate part of the first collecting pipe DI, and the connecting part A of the single pipe S3 extending from the #3 cylinder,
2. Single tube S2 extending from #5 cylinder. The connecting portion C of S5 to the second collecting pipe D2 is arranged at a distance H from the starting end of the third collecting pipe D3.

By configuring like this, it will fire late #
Attenuation and time delay occur when the positive pressure wave caused by the exhaust air blowing from the third cylinder propagates to the #5 cylinder, and an increase in the pressure in the exhaust pipe during the valve weight period of the #5 cylinder is prevented.

Although the embodiments of the exhaust manifold for a five-cylinder engine according to the present invention have been described in detail above, the present invention is not limited to the above embodiments, and without departing from the scope of the present invention as set forth in the claims. , it is possible to make various minor design changes.

For example, the method of dividing five cylinders into three cylinders connected to the first collecting pipe and two cylinders connected to the second collecting pipe is not limited to that of the above embodiment, but may be as shown in Fig. 6b. It is also possible. Further, the firing order of the cylinders is not limited to that of the above embodiment, but can be set as appropriate depending on the classification of the cylinders.

Furthermore, the distance in the first embodiment and its modifications,
In the C1 invention, the distance H in the second embodiment is not limited to a predetermined value, but should be appropriately determined by experiment etc. according to the characteristics of various five-cylinder engines to which the present invention is applied. Effects As described above, the exhaust manifold for a five-cylinder engine of the present invention has a predetermined positional relationship on the exhaust manifold for the single pipes extending from two cylinders where the ignition order is consecutive and exhaust interference is likely to occur. Since the valves of the cylinders that were ignited earlier are connected to each other, it is possible to attenuate the positive pressure waves generated by the exhaust air blowing from the cylinders that were ignited later, and to propagate these positive pressure waves with a time delay. The propagation of the positive pressure wave during the weight period and the occurrence of exhaust interference are effectively prevented. Therefore, a decrease in volumetric efficiency due to exhaust interference is prevented, and it is possible to increase engine output.

Also, the number of pipes connected to the joint flange is 1 or 2.
It can be a book, and can contribute to improving space efficiency and reducing weight.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a first embodiment of an exhaust manifold for a five-cylinder engine according to the present invention, FIG. 2 is an explanatory diagram of its operation, and FIG. 3 is a diagram showing a modification of the first embodiment. Fig. 4 shows a second embodiment of the exhaust manifold for a five-cylinder engine according to the present invention, Figs. 5a and 5b show a conventional 5-1 collective exhaust manifold, and Figs. 6a and 6b show a conventional exhaust manifold. Figure 7 is a diagram showing a conventional 5-3 exhaust manifold, Figure 8 is a diagram showing variations in exhaust pipe pressure with respect to crank angle, Figure 9 is a diagram showing a 5-2 exhaust manifold.
The figure is a diagram showing the relationship between volumetric efficiency and exhaust pipe internal pressure during the valve weight period. D1 to D3...collecting pipe, M...exhaust manifold,
S1~S5...Single pipe, #1~#5...Cylinder
・Cylinder block, 2...Joining flange, 3...
Muffler, 4...Nigagest pipe Fig. 5b Fig. 5a

Claims (2)

[Claims] (1) Any three of the five cylinders (#1 to #5) arranged in one direction in the cylinder block (1)
Three single pipes extending from each cylinder are connected to the first collecting pipe (D1
), and the two single pipes extending from the remaining two cylinders are collected into a second collecting pipe (D2), and these first
, in an exhaust manifold for a five-cylinder engine in which the second collecting pipes (D1, D2) are connected to the joining flange (2); An exhaust manifold for a five-cylinder engine, characterized in that either one of the pipes is connected to the middle part of the first collecting pipe (D1) in a shifted manner. (2) The first and second collecting pipes (D1, D2) are combined into the third collecting pipe (D3) in front of the joining flange (2), and
The connection part of the staggered connected single pipes to the middle part of the first collecting pipe (D1) and the connecting part of the two single pipes to the second collecting pipe (D2) are connected to the third collecting pipe (D3). ) The exhaust manifold for a five-cylinder engine according to item (1), characterized in that the exhaust manifold is located at different distances from the exhaust manifold.