JPH059485Y2 - - Google Patents

Description

[Detailed description of the invention] <Industrial application field> This invention relates to an engine exhaust gas recirculation device, and is a technology that improves the combustion efficiency of the engine by effectively utilizing the heat content of the recirculated exhaust gas. be.

<Prior Art> The present invention relates to an exhaust gas recirculation device for an engine whose basic structure is as follows.

For example, as shown in FIG. 1 or FIG. 5, the intake and exhaust ports 7 and 8 of the engine 1 are configured to be opened and closed by a rotary valve 9, and the rotary valve 9 has an intake valve hole 13 in a rotary shaft valve body 12. and an exhaust valve hole 14, so that a part of the exhaust gas discharged from the exhaust port 8 is recirculated from the intake port 7 to the combustion chamber 5 through the recirculation path 15.

Conventionally, in the above-mentioned basic structure, the recirculation passage 15 was provided outside the headblock 40 of the engine 1, as shown in FIG. That is, the intake pipe 41 and the exhaust pipe 42 are connected via a reflux pipe 43, and the reflux passage 15 is formed within the reflux pipe 43.

<Problems to be solved by the invention> In the conventional structure described above, exhaust gas discharged from the exhaust port 8 is recirculated into the intake pipe 41 due to exhaust pressure, but this exhaust gas flows through the exhaust pipe 42 and the recirculation pipe 43. The temperature tends to drop due to heat dissipation while passing through. For this reason, when the reflux gas is refluxed into the intake pipe 41, the amount of heat it holds decreases, and only a part of the amount of heat that this reflux gas originally had is used to heat the mixture (or air). There is a problem in that the amount of heat held in the reflux gas cannot be used effectively in promoting the vaporization of the gas (or increasing the temperature of the air) to improve combustion efficiency.

The present invention aims to improve the combustion efficiency of the engine by preventing the temperature of the reflux gas from decreasing and effectively utilizing its retained heat to heat the air-fuel mixture (or air).

<Means for Solving the Problems> In order to achieve the above object, the present invention, for example, as shown in FIG. The valve opening timing of the exhaust valve hole 14 is set to overlap with the opening timing of the exhaust valve hole 14, and the recirculation path 15 is formed in the rotary shaft valve body 12 by a communication hole that communicates the intake valve hole 13 and the exhaust valve hole 14. It is characterized by the fact that

<Operation> According to the present invention, the intake valve hole 13 and the exhaust valve hole 14
When the valve opening timings of the two overlap, a part of the exhaust gas discharged from the exhaust port 8 is recirculated from the intake port 7 to the combustion chamber 5 through the recirculation path 15 in the rotary shaft valve body 12 due to exhaust pressure. .

Since the rotary shaft valve body 12 is maintained at a high temperature by receiving heat from the combustion chamber 5, the temperature of the exhaust gas decreases little while passing through the recirculation path 15, and the amount of heat held by the recirculation gas hardly decreases. Therefore, almost all of the heat held by the reflux gas is used to heat the mixture (or air), promoting vaporization of the mixture (or increasing the temperature of the air) and improving combustion efficiency.

<Example> Hereinafter, an example of this invention will be described with reference to FIGS. 1 to 4.

1 is a vertical engine, cylinder block 2
A cylinder head 3 is attached to the upper part of the piston 4, and a combustion chamber 5 is formed between the lower surface of the cylinder head 3 and the top surface of the piston 4.

The cylinder head 3 is formed with an intake port 7 and an exhaust port 8 whose axes are vertical and circular in cross section. A rotary valve 9 for opening and closing these intake and exhaust ports 7 and 8 is fitted into the cylinder head 3 in an airtight manner. The rotary valve 9 has a rotary shaft valve body 12 whose axis is horizontally oriented, and an intake valve hole 13 and an exhaust valve hole 14 are provided through the rotary shaft valve body 12 in the radial direction. In the figure, arrow R indicates the rotation direction of the rotary shaft valve body 12.

In the above configuration, a recirculation path 15 that recirculates a portion of the exhaust gas discharged from the exhaust port 8 to the combustion chamber 5 is formed in the rotary shaft valve body 12. The reflux passage 15 has a horizontal axis and a circular cross-sectional view, and allows the intake port 7 and the exhaust port 8 to communicate with each other. When the intake valve hole 13 and the exhaust valve hole 14 overlap (as shown in FIG. 2), a part of the exhaust gas discharged from the exhaust port 8 passes through the recirculation path 15 and the intake port 7 to the combustion chamber. 5.

Further, an exhaust gas recirculation valve 18 that opens and closes the recirculation path 15 is attached to the rotary shaft valve body 12 . In FIG. 3, the state in which the exhaust gas recirculation valve 18 opens the recirculation path 15 is shown by a solid line, and the state in which it is closed is shown by a chain double-dashed line.

That is, a semicircular valve groove 19 is formed in the axial direction midway of the rotary shaft valve body 12 when viewed from the side, and the reflux path 15 is divided in the axial direction by this valve groove 19 .

A rotating ring 20 is rotatably fitted around the outer periphery of the rotating shaft valve body 12 so as to cover the opening of the valve groove 19 . A valve body 21 is provided protruding from the inner circumferential surface of the rotary ring 20 in the axial direction, and this valve body 21 is attached to the valve groove 1.
9 so that it can rotate and slide freely. The above valve body 21
A compression spring 22 is provided between the bottom surface 19a of the valve groove 19 and
is installed (as shown in Fig. 3), and this compression spring 2
2, the rotary shaft valve body 12 and the rotary ring 20 can rotate together.

Then, as shown by the solid line in FIG. 3, the rotation ring 20 is rotated (arrow A) in the opposite direction to the rotation direction (arrow R) of the rotary shaft valve body 12, and the compression spring 22 by the valve body 21 is rotated. When the amount of compression is increased, the reflux path 15 is opened. On the other hand, as shown by the two-dot chain line in FIG.
When the amount of compression is made small, the reflux path 15 is closed.

Next, a means for rotating the above-mentioned rotating ring 20 will be explained.

An operating ring 24 is fitted onto the outer periphery of the rotating ring 20.
The operating ring 24 is connected to the rotating shaft valve body 12 via a linear guide 27 consisting of a guide hole 25 formed in the peripheral wall 24a of the operating ring 24 in the axial direction and a guide pin 26 protruding from the rotating shaft valve body 12. relative sliding is possible only in the axial direction. Further, a rotation guide 29 is provided that rotates the rotation ring 20 when the operation ring 24 is slid in the axial direction. This rotation guide 29 is connected to the peripheral wall 2 of the operation ring 24.
It consists of a guide hole 30 formed to extend diagonally in 4a, and a guide pin 31 that protrudes from the rotation ring 20 and is slidably fitted into the guide hole 30. Note that 32 is a fork for slidingly operating the operating ring 24 in the axial direction.

When the fork 32 is operated to slide the operation ring 24 to the position shown by the solid line in FIGS. 1 and 4 (arrow C in FIG. 4), the rotation ring The rotary shaft 20 is rotated in the opposite direction to the valve body 12 (arrow A in FIGS. 3 and 4). As a result, as described above, the valve body 21 allows the reflux path 1 to
5 will be held.

On the other hand, contrary to the above, when the fork 32 is operated to slide the operation ring 24 to the position shown by the two-dot chain line in FIGS. 1 and 4 (arrow D in FIG. 4), the rotation guide 29, the rotating ring 20 connects to the rotating shaft valve body 12.
(arrow B in Figures 3 and 4). Thereby, as described above, the reflux path 15 is closed by the valve body 21.

<Effects of the invention> Since the present invention is constructed and operates as described above, a part of the exhaust gas is smoothly recirculated to the intake port side by the exhaust pressure, and the temperature of the recirculated exhaust gas is Since the drop is small, almost all of the retained heat is used to heat the air-fuel mixture (or air), promoting vaporization of the air-fuel mixture (or increasing the temperature of the air) and improving combustion efficiency.

[Brief explanation of the drawing]

1 to 4 show examples of this invention,
Figure 1 is a vertical sectional view of the upper part of the engine, Figure 2 is a vertical cross-sectional view of the upper part of the engine.
3 is a sectional view taken along the - line in FIG. 1, FIG. 4 is a sectional view taken along the - line in FIG. 1, and FIG. 5 is a schematic diagram showing a conventional example It is a diagram. DESCRIPTION OF SYMBOLS 1... Engine, 5... Combustion chamber, 7... Intake port, 8... Exhaust port, 9... Rotary valve, 12... Rotating shaft valve body, 13... Intake valve hole, 1
4...Exhaust valve hole, 15...Recirculation path, 18...Exhaust recirculation valve.

Claims (1)

[Claims for Utility Model Registration] 1. The intake and exhaust ports 7 and 8 of the engine 1 are configured to be opened and closed by a rotary valve 9, and the rotary valve 9 has an intake valve hole 13 and an exhaust valve hole 14 in a rotating shaft valve body 12. In an engine exhaust gas recirculation device configured to open a space between the exhaust port 8 and recirculate a part of the exhaust gas discharged from the exhaust port 8 through the recirculation path 15 from the intake port 7 to the combustion chamber 5, The opening timing of the valve hole 13 is set to partially overlap with the opening timing of the exhaust valve hole 14, and the recirculation passage 15 is formed into a communication hole that communicates the intake valve hole 13 and the exhaust valve hole 14. An exhaust gas recirculation device for an engine, characterized in that it is formed within a rotary shaft valve body 12. 2. The exhaust gas recirculation device for an engine according to claim 1, wherein an exhaust gas recirculation valve 18 for opening and closing the recirculation passage 15 is attached to the rotary shaft valve body 12.