JPS5852352Y2 - Internal combustion engine exhaust gas recirculation device - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement of an exhaust gas recirculation device for an internal combustion engine.

The exhaust gas recirculation device recirculates part of the exhaust gas to the intake system depending on the operating conditions of the engine, thereby suppressing the maximum combustion temperature and reducing the amount of NOx generated.

Conventionally, this exhaust gas recirculation device has been designed to simplify the passage configuration by forming an exhaust gas recirculation passage in the cylinder head and the intake pipe, and to preheat the intake air using the heat of the recirculated exhaust gas. There are known things that have made it possible.

As this type of prior art, for example,
Examples include those described in Japanese Patent No. 128.

However, in the prior art described above, the exhaust gas recirculation passage has a single passage configuration in which it passes from the exhaust port of one cylinder through the cylinder head, through one branch pipe of the intake manifold, and into the intake system. The intake preheating effect performed using the heat of the recirculated exhaust gas is not only limited to preheating the air-fuel mixture supplied to some cylinders, but also for EGR.
When the pulp closes and the exhaust gas recirculation is stopped, the exhaust gas does not flow through the recirculation passage, so the intake prevention heat effect cannot be obtained when the exhaust gas recirculation is stopped.

In view of the above-mentioned points, the present invention improves the passage configuration of the recirculation passage to have an intake air preheating effect not only during exhaust gas recirculation but also when recirculation is stopped, and moreover, to preheat the intake air of the air-fuel mixture to all cylinders. It is an object of the present invention to provide an improved exhaust gas recirculation device that can perform the following functions.

For this purpose, the present invention focuses on the fact that in the case of a horizontally opposed internal combustion engine, the intake pipe is arranged in a sheath-like manner above the engine body, spanning the left and right opposing cylinders. An exhaust gas recirculation passage is formed in each cylinder head of the cylinder, one end of which communicates with the respective exhaust port, and these left and right exhaust gas recirculation passages are connected within the pipe wall along the entire length of the suction pipe, such as at the suction pipe attachment part. The exhaust gas recirculation passages are configured to communicate with each other through the provided exhaust gas recirculation passages, and the exhaust gas recirculation passages are communicated with the suction passage in the suction pipe through a recirculation control valve disposed in the center of the suction pipe. The exhaust gas is characterized in that the exhaust gas flows through the exhaust gas recirculation passage formed in the pipe wall over the entire length of the suction pipe, not only when the exhaust gas is recirculated, but also when the recirculation is stopped.

This will be explained below with reference to the drawings.

The button 1 in the figure is a horizontally opposed engine, with two cylinders formed on each side, and in the cylinder heads 2 and 3, the intake port 4 and exhaust port 5 of each of the two cylinders are reduced to one, and a common opening is formed. is forming.

A suction pipe 7 is connected to a common opening 6 of the suction port 4 .

Above the engine, the suction pipe 7 is comprised of a branch passage 8 and a common passage 9 which are symmetrically shaped, and further has a carburetor 10 above the center thereof.

Exhaust gas recirculation passages 11 are opened in the exhaust ports 5 of each pair of left and right cylinders, and these left and right exhaust gas recirculation passages 11
passes through the respective cylinder heads 2 and 3 to the suction pipe attachment portion, where it communicates with an exhaust gas recirculation passage 12 provided in the pipe wall in the lower half of the suction pipe 7.

The passage 12 penetrates the inside of the pipe wall over the entire length of the suction pipe I, and the exhaust gas recirculation passages 11.11 formed in the left and right cylinder heads 2 and 3 extend inside the pipe wall of the suction pipe T. They communicate with each other via an exhaust gas recirculation passage 12 provided.

The exhaust gas recirculation passage 12 is located at the center of the suction pipe 7.
J, - communicates with a reflux control valve 13 provided in the common path 9.

The control valve 13 is for introducing and stopping exhaust gas into the suction pipe T, and the diaphragm 1 operates the valve body 14.
5 and a negative pressure chamber 16, the negative pressure chamber 16 communicating with the throttle valve 11 immediately upstream of the idle position through a conduit 18.

Therefore, when the throttle valve 17 opens and the negative pressure in the carburetor suction passage becomes high, the diaphragm 15 is deflected, the gas 14 is drawn in, the control valve 13 is opened, and part of the exhaust gas is transferred to the recirculation passage 11.12. When the exhaust gas is recirculated in this way, it flows close to the suction passage in the suction pipe T, so the amount of the recirculated exhaust gas is Heat can be used to preheat the intake air.

This preheating of the intake air promotes fuel atomization, completes combustion, and helps purify exhaust gas.

At high speeds, high loads, or idle speeds when the negative pressure in the carburetor suction passage becomes small, the control valve 13 closes and the recirculation of exhaust gas is stopped. In this case, the exhaust ports 5 of the left and right cylinders Since the exhaust gas recirculation passages ii and i1 are in communication with each other via the exhaust gas recirculation passage 12 provided on the wall of the suction pipe 7, the exhaust gas pulsation causes the exhaust gas recirculation to stop when the recirculation is stopped. However, a portion 75 of the exhaust gas discharged from the exhaust port 5 of the cylinder on one side alternately flows toward the cylinder on the other side via the exhaust gas recirculation passage 11.12. Even when the reflux is stopped, the above-mentioned intake preheated young fruit can be obtained due to the heat of the exhaust gas.

Furthermore, the exhaust gas recirculation passage 12 penetrates the inside of the pipe wall over the entire length of the suction pipe 7, and the air-fuel mixture is passed from the central carburetor 10 to the left and right cylinders via the suction pipe 7 that extends horizontally symmetrically. Since it is supplied to the intake port 4, the air-fuel mixture supplied to all cylinders can be preheated.

In this way, in addition to the reduction in NOx due to exhaust gas recirculation, combustion is improved by intake air preheating, making it possible to comprehensively reduce harmful components in the exhaust gas.

As is clear from the above, according to the present invention, the exhaust gas recirculation passage passes through the cylinder head from the exhaust port of the left and right cylinders, passes through the pipe wall of the suction pipe, reaches the control valve, and connects the suction pipe. Since the exhaust gas recirculation passage is provided so as to communicate with the exhaust gas recirculation passage, all of the exhaust gas recirculation passage is housed within the cylinder head and the intake pipe, and does not protrude to the outside.

Therefore, special piping parts for configuring the exhaust gas recirculation passage can be eliminated, and since the piping for configuring the passage is not exposed to the outside, space can be saved, and the size is small and maintainability is improved.

Furthermore, since the exhaust gas is configured to flow through the exhaust gas recirculation passage not only during recirculation but also when recirculation is stopped, the heat of the exhaust gas preheats the intake air in all operating ranges and promotes the vaporization of the fuel. The exhaust gas purification effect can be enhanced.

[Brief Description of the Drawings] Fig. 1 is a front view showing an embodiment of the present invention, Fig. 2 is a plan view of the same, Fig. 3 is a sectional view taken along the line ■-■ of Fig. 2, and Fig. 4 is an exhaust port. FIG. 1... Engine, 2, 3... Cylinder head, 4... Intake port, 5... Exhaust port, 6... Opening, 7... Suction pipe, 8... Branch path, 9... Common path, 10
...... Vaporizer, 11. 12... Exhaust gas recirculation passage, 13... Control valve, 14...
・Valve body, 15...Diaphragm, 16...
... Negative pressure chamber, valve, 18... conduit. 17...Slot

Claims (1)

[Scope of utility model registration request] A horizontally opposed engine in which the cylinders are arranged horizontally facing each other, and the intake pipe is arranged in a ring shape above the engine body, spanning the left and right cylinders and extending symmetrically horizontally, with the central part communicating with the carburetor. Then, by connecting both ends of the suction pipe to the intake ports of the left and right cylinders, an exhaust gas recirculation passage is formed in each cylinder head of the left and right cylinders, with one end communicating with the exhaust port. , the left and right exhaust gas recirculation passages are communicated with each other via an exhaust gas recirculation passage provided in the pipe wall from the suction pipe attachment part over the entire length of the suction pipe; An exhaust gas recirculation device for an internal combustion engine, characterized in that the exhaust gas recirculation device for an internal combustion engine is connected to an intake passage in an intake pipe via a recirculation control valve disposed in the center of the pipe.