JPH0441224Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention is used to prevent intake air interference in a multi-cylinder engine.

[Conventional technology]

In a multi-cylinder engine, a phenomenon called intake interference occurs.

Let me briefly explain intake interference.

FIG. 6 schematically represents a four-cylinder engine. In FIG. 6, 1, 2, 3, and 4 are the first cylinder, the second cylinder, the third cylinder, and the fourth cylinder, respectively. Also, 11, 12, 13, 14
are the intake manifold connected to the first cylinder 1, the intake manifold connected to the second cylinder 2, and the third cylinder, respectively.
Intake manifold connected to No. 3 cylinder, No. 4 cylinder 4
This is the intake manifold connected to the

5 is a surge tank. Each intake manifold 1
1, 12, 13, and 14 are connected to the surge tank 5. As can be seen from the presence of the surge tank 5, the engine shown in FIG. 6 is a fuel-injected gasoline engine.

There are two types of firing orders for four-cylinder engines.
One of them is the order of the first cylinder, the third cylinder, the fourth cylinder, and the second cylinder. It is assumed that the engine shown in FIG. 6 is ignited in this ignition order.

Then, air intake is also performed in the order of the first cylinder, the third cylinder, the fourth cylinder, and the second cylinder.

Now, let us consider what happens when the flow of intake air switches from the first cylinder to the third cylinder. When intake air is flowing to the No. 1 cylinder, the air flows as shown by arrow A. When intake air flows into the third cylinder as shown by arrow B, the flow of arrow A must change direction to arrow B. However, since the air flow has inertia, the flow of arrow A cannot suddenly change direction to arrow B. Therefore, the amount of air taken into the No. 3 cylinder ends up decreasing. This is the phenomenon called intake interference mentioned above.

The intake interference has been explained only for the 3rd cylinder, but as long as air is taken in in the order of the 1st cylinder → 3rd cylinder → 4th cylinder → 2nd cylinder, intake interference will occur for all cylinders. can occur.

If intake interference occurs, as described above, the amount of intake air to each cylinder decreases, resulting in a decrease in engine output. Therefore, intake interference is not desirable.

Various techniques have been proposed in the past to prevent the occurrence of intake interference. Techniques for preventing the occurrence of intake air interference include, for example, Japanese Patent Application Laid-Open No. 56-115818 and Japanese Utility Model Application Laid-Open No. 60-69327.

Development of technology to prevent conventional intake interference
This will be explained using 60-69327 as an example.

Figure 7 is a reproduction of the drawing in Utility Model Application Publication No. 60-69327.

In FIG. 7, 21 is an engine body, and 22 is an exhaust manifold. Also, 11, 12, 1
3 and 14 are an intake manifold connected to the first cylinder, an intake manifold connected to the second cylinder, an intake manifold connected to the third cylinder, and an intake manifold connected to the fourth cylinder, respectively.

5 is a surge tank. Each intake manifold 1
1, 12, 13, and 14 are connected to the surge tank 5. As can be seen from the presence of the surge tank 5, the engine shown in FIG. 7 is a fuel-injected gasoline engine.

In the engine shown in Fig. 7, the firing order is No. 1 cylinder → No. 3 cylinder → No. 4 cylinder → No. 2 cylinder.
Assume that it is the number cylinder.

In the one shown in FIG. 7, intake manifolds connected to adjacent cylinders in the ignition order are separated by a partition wall 23 inside the surge tank 5 to prevent intake interference.

That is, as can be seen from FIG. 7, the inside of the surge tank 5 is divided into two upper and lower chambers 2 by the partition wall 23.
It is divided into 4 and 25 sections. The intake manifolds 12 and 13 are communicated with the upper chamber 24,
Intake manifolds 11 and 14 communicate with lower chamber 25.

It is easy to understand from the following explanation that this will eliminate intake interference.

That is, let us consider a case where the flow of intake air is switched from the first cylinder to the third cylinder. 1st
When intake air is flowing to the number cylinder, arrow A
There is a flow of air like this. However, when the intake air flows into the third cylinder as shown by arrow B, there is no need to change the direction of the flow from arrow A to arrow B because of the partition wall 23. Therefore, the amount of air taken into the third cylinder does not decrease. Note that when the flow of intake air switches from the 3rd cylinder to the 4th cylinder, time has elapsed since the air flow to the 1st cylinder as shown by arrow A has stopped. The amount of air taken into the cylinder does not decrease. This applies not only to the third and fourth cylinders but also to all other cylinders. In the end, this means that there is no intake interference.

[Problem that the invention attempts to solve]

The one shown in FIG. 7 is certainly successful in eliminating intake interference.

However, apart from that, the second and third cylinders
There was a problem that the amount of intake air to the No. 1 cylinder decreased, and the amount of intake air to the No. 1 and No. 4 cylinders increased (this was because the throttle valve was located close to the partition wall 23). This creates an imbalance in which the output of the 2nd and 3rd cylinders is small and the output of the 1st and 4th cylinders is large, which increases the risk of engine vibration. Ta.

In Figure 7, the amount of air taken into the No. 2 and No. 3 cylinders becomes smaller, and the amount of air taken into the No. 1 and No. 4 cylinders increases for the following reasons. .

That is, in FIG. 8, 31 is a throttle valve;
32 is a rotation axis. Arrow C is the throttle valve 31
represents the direction in which it opens. As can be seen from FIG. 8, normally, the throttle valve 31 has its rotation shaft 32 placed horizontally. Therefore, the throttle valve 3
The flow rate of air flowing above the throttle valve 1 (arrow D) is small, and the flow rate of air flowing below the throttle valve 31 (arrow E) is large. Therefore, if the surge tank 5 is partitioned into upper and lower parts as shown in FIG. 7, the amount of air flowing into the upper chamber 24 will be smaller, and the amount of air flowing into the lower chamber 25 will be larger. For this reason, the amount of intake air to the No. 2 and No. 3 cylinders decreases, and the amount of intake air to the No. 1 and No. 4 cylinders increases. It goes without saying that if the direction in which the valve 31 opens is opposite to the direction of arrow C, the above-mentioned relationship between the amount of intake air and the amount of intake air will be reversed.)

The present invention solves these problems of the conventional technology.

The technical problem of the present invention is to prevent intake air interference without creating an imbalance in the amount of intake air to each cylinder.

Note that if the rotation axis of the throttle valve is made vertical instead of horizontal, the imbalance in the amount of intake air to each cylinder will theoretically be eliminated. However, this cannot actually be done for the following two reasons.

First, if the axis of rotation of the throttle valve is vertical rather than horizontal, the throttle valve becomes difficult. To avoid this, it would be possible to install a thrust bearing, but this would increase costs.

Second, if the rotation axis of the throttle valve is made vertical rather than horizontal, the oil lubricating the rotation shaft will flow down.

For the two reasons mentioned above, the rotation axis of the throttle valve cannot be made vertical.

[Means for solving problems]

By the way, in order to achieve the above-mentioned technical problem, the following measures are taken in the present invention.

That is, in the intake interference prevention device for a multi-cylinder engine according to the present invention, an intake manifold extends from the engine main body for each cylinder, and these intake manifolds are connected to a surge tank. A throttle body is located upstream of the surge tank. A throttle valve is housed inside the throttle body. The inside of the surge tank is divided into upper and lower chambers by a partition wall. The intake manifolds connected to adjacent cylinders in the ignition order are separated by a partition wall inside the surge tank. The partition wall extends to the vicinity of the throttle valve, and the partition wall is twisted approximately 90 degrees in the vicinity of the throttle valve. As a result, the surface of the partition wall is substantially perpendicular to the rotation axis of the throttle valve.

The above are the measures taken in the present invention.

[Function] In this invention, since a partition wall is provided inside the surge tank, for the reason mentioned above,
This will eliminate intake interference.

By the way, the following matters are important in this invention. That is, as mentioned earlier, the flow rate of air flowing above the throttle valve is small, and the flow rate of air flowing below the throttle valve is large. The wall extends close to the throttle valve, but is twisted approximately 90 degrees so that the plane of the partition wall is approximately perpendicular to the axis of rotation of the throttle valve.

Therefore, the amount of air flowing into the upper and lower chambers partitioned by the partition wall in the surge tank becomes equal.

Therefore, the amount of air taken into each cylinder is also equal.

Thus, according to the present invention, it is possible to prevent intake interference without creating an imbalance in the amount of intake air to each cylinder.

The effect of the present invention will be made clearer from the following examples.

〔Example〕

FIG. 1 is a perspective view of an intake air interference prevention device for a multi-cylinder engine according to a first embodiment of the present invention.

In FIG. 1, 21 is an engine body, and 22 is an exhaust manifold. Also, 11, 12, 1
3 and 14 are an intake manifold connected to the first cylinder, an intake manifold connected to the second cylinder, respectively;
The intake manifold is connected to the third cylinder, and the intake manifold is connected to the fourth cylinder.

5 is a surge tank. Each intake manifold 1
1, 12, 13, and 14 are connected to the surge tank 5. As can be seen from the presence of the surge tank 5, the engine in FIG. 1 is a fuel-injected gasoline engine.

In the engine shown in Fig. 1, the ignition order is No. 1 cylinder → No. 3 cylinder → No. 4 cylinder → No. 2 cylinder.
Assume that it is the number cylinder.

In the one shown in FIG. 1, intake manifolds connected to adjacent cylinders in the ignition order are separated by a partition wall 23 inside the surge tank 5 to prevent intake interference.

That is, as can be seen from FIG. 1, the inside of the surge tank 5 is divided into two upper and lower chambers 2 by the partition wall 23.
It is divided into 4 and 25 sections. The intake manifolds 12 and 13 are communicated with the upper chamber 24,
Intake manifolds 11 and 14 communicate with lower chamber 25.

The process up to this point is exactly the same as the conventional method (FIG. 7).

In this embodiment, the partition wall 23 is the surge tank 5.
It extends to the intake passage 41 upstream of the
It is distinctive in that it is twisted 90 degrees.

A throttle body 42 is located upstream of the intake passage 41.
is located. In addition, the throttle body 42
Further upstream, an air flow meter and an air cleaner (both not shown) are present via a duct (not shown).

A throttle valve 31 is arranged inside the throttle body 42. The rotation shaft 32 of the throttle valve 31 is arranged horizontally. This is for the reason stated earlier.

As can be seen from FIG. 1, in this embodiment, the partition wall 23 extends to the vicinity of the throttle valve 31, and the surface of the partition wall 23 is approximately perpendicular to the rotation axis 32 in the vicinity of the throttle valve 31. has been done.

The operation of this embodiment will be explained.

For example, consider when the flow of intake air is switched from the first cylinder to the third cylinder. When intake air is flowing to the No. 1 cylinder, the air flows as shown by arrow A. When intake air can flow into the third cylinder as shown by arrow B, there is no need to change the direction of the flow from arrow A to arrow B because of the partition wall 23. Therefore, the amount of air taken into the third cylinder does not decrease.
Note that when the flow of intake air switches from the 3rd cylinder to the 4th cylinder, time has elapsed since the air flow to the 1st cylinder as shown by arrow A has stopped. There is no reduction in the amount of air taken into the As you will soon see, this applies not only to cylinders 3 and 4, but also to all other cylinders. In the end, according to this embodiment, intake interference is eliminated.

The following matters are important in this embodiment. That is, as mentioned earlier, the flow rate of air flowing above the throttle valve 31 (arrow D) is small, and the flow rate of air flowing below the throttle valve 31 (arrow E) is large; In the example, the partition wall 23 extends to the vicinity of the throttle valve 31, and is twisted by 90 degrees. For this reason, the upper chamber 2 of the surge tank 5
4 and the amount of air entering the lower chamber 25 are to be equal.

Therefore, the amount of intake air into the second cylinder and the third cylinder and the amount of intake air into the first cylinder and the fourth cylinder are equal.

Thus, according to this embodiment, it is possible to prevent intake interference without creating an imbalance in the amount of intake air to each cylinder.

Note that if the interior of the surge tank 5 is divided into left and right sides instead of using the partition wall 23 vertically, the partition wall 23 can be placed near the throttle valve 31.
There is no need to twist it 90 degrees.

However, this is not practical for the following reasons.

That is, in FIGS. 2 and 3, the surge tank 5
The inside of the box is shown divided vertically and horizontally by a partition wall 23. 2 shows the inside of the surge tank 5 divided vertically by a partition wall 23, and FIG. 3 shows the inside of the surge tank 5 divided horizontally by the partition wall 23.

In FIGS. 2 and 3, 21 is the engine body, and 11, 12, 13, and 14 are intake manifolds.

As can be seen from the comparison between Figures 2 and 3, the inside of the surge tank 5 is partitioned into left and right sides (3
Figure 2) has a higher height (H>h) than the surge tank 5 which is partitioned into upper and lower parts (Figure 2).

Therefore, considering the mountability of the engine, it is not practical to partition the interior of the surge tank 5 into left and right sides by the partition wall 23.

FIG. 4 is a perspective view of an intake air interference prevention device for a multi-cylinder engine according to a second embodiment of the present invention.

In the one shown in FIG. 4, a hole 51 is bored in the partition wall 23, and a control valve 52 for opening and closing the hole 51 is provided.

53 is a drive device that drives the control valve 52; 54
is a control device that controls the drive device 53; and 55 is an engine operating state detection sensor that detects the operating state of the engine and inputs its signal to the control device 54.

Examples of the engine operating state detection sensor 55 include an engine rotation speed sensor, an intake air amount sensor, and the like. Hereinafter, a case where the engine operating state detection sensor 55 is an engine rotation speed sensor will be described.

Generally speaking, in engines, "effective intake pipe length"
There is a concept. The effective intake pipe length is the actual length of the intake pipe that causes air column vibration in the intake air.

In the case of the engine shown in FIG. 1, the effective intake pipe length is the sum of the length of the intake manifold and the length of the intake port of the cylinder head (a), the length b from the surge tank 5 to the tip of the partition wall 23, and It is known that the result is (a+b).

However, as shown in Fig. 5, it is known that in a normal engine without a partition wall, the effective intake pipe length is the sum of the length of the intake manifold and the length of the intake port of the cylinder head. It is being In FIG. 5, 21 is an engine body, 22 is an exhaust manifold, 5 is a surge tank, and 11, 12, 13, and 14 are intake manifolds.

On the other hand, there are two facts as follows.

First, when the engine is running at low to medium speeds, the longer the effective intake pipe is, the better the engine output will be, but when the engine is running at high speeds, the shorter the effective intake pipe will be, the better the engine output will be. Therefore, when the engine rotates at low to medium speeds, the structure as shown in FIG. 1 improves the output, but when the engine rotates at high speeds, the structure as shown in FIG. 5 improves the output.

Second, when the engine rotates at low or medium speeds, the intake interference as described above becomes a problem, but when the engine rotates at high speeds, intake interference does not become a problem (almost never occurs). Therefore, the structure shown in FIG. 1 is preferable when the engine rotates at low to medium speeds, but the structure shown in FIG. 5 may be used instead of the structure shown in FIG. 1 when the engine rotates at high speeds.

Therefore, the structure shown in Fig. 4 has a structure substantially similar to that shown in Fig. 1 when the engine rotates at low to medium speeds,
When the engine rotates at high speed, the structure is substantially as shown in FIG. 5 to improve the engine output.

That is, in the second embodiment, as can be seen from FIG. 4, a hole 51 is formed in the partition wall 23, and the hole 51 is opened and closed by a control valve 52 as follows.

If the engine speed is lower than the specified value,
The hole 51 is closed by a control valve 52, and when the engine speed reaches a predetermined value or higher, the hole 51 is opened by the control valve 52. If the hole 51 is closed, the engine in FIG. 4 becomes substantially the same as the engine in FIG. 1, and if the hole 51 is opened, the engine in FIG. This is because it is the same as an engine like this.

Needless to say, these operations are performed by the control device 54 and the drive device 53 based on the signal from the engine operating state detection sensor 55.

Thus, the second embodiment has the advantage that it is possible to fully exhibit the performance of the engine over the entire engine speed range from the low speed rotation range to the high speed rotation range.

Since the other matters in FIG. 4 are exactly the same as those in FIG. 1, the reference numerals in FIG. 4 will only be used and further explanation will be omitted.

[Effect of idea]

As can be seen from the description of the above embodiments, the present invention has the effect that intake air interference can be prevented without creating an imbalance in the amount of intake air to each cylinder.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an intake interference prevention device for a multi-cylinder engine according to a first embodiment of the present invention, and FIG. 2 is an explanatory diagram of an engine in which the inside of a surge tank is divided into upper and lower parts by a partition wall. , FIG. 3 is an explanatory diagram of an engine in which the interior of the surge tank is divided into left and right sides by a partition wall, and FIG. 4 is a perspective view of an intake interference prevention device for a multi-cylinder engine according to a second embodiment of the present invention. , FIG. 5 is a perspective view of a normal multi-cylinder engine without a partition wall, FIG. 6 is an explanatory diagram of the engine to explain intake interference, and FIG. 7 is an intake interference of a conventional multi-cylinder engine. A perspective view of the prevention device, FIG. 8, is a longitudinal sectional view of the throttle valve. 5...Surge tank, 11, 12, 13, 14
...Intake manifold, 21 ...Engine body, 2
3... Partition wall, 24... Upper chamber, 25... Lower chamber,
31...throttle valve, 32...rotation shaft, 42...
...Throttle body.

Claims (1)

[Claim for Utility Model Registration] Intake manifolds extend from the engine body for each cylinder, and these intake manifolds are connected to a surge tank, and a throttle body is disposed upstream of the surge tank. A throttle valve is housed inside the throttle body, and the inside of the surge tank is divided into upper and lower chambers by a partition wall. In the intake air interference prevention device for a multi-cylinder engine partitioned by the partition wall, the partition wall extends to the vicinity of the throttle valve, and the partition wall is twisted approximately 90 degrees in the vicinity of the throttle valve. 2. An intake air interference prevention device for a multi-cylinder engine, characterized in that the partition wall is substantially perpendicular to the rotation axis of the throttle valve.