JPH0612746U - Combustion chamber of a sub-chamber internal combustion engine - Google Patents

Abstract

(57) [Summary] [Object] The object of the present invention is to uniformly and efficiently cool the outer peripheral surface of the sub-chamber mouthpiece 8 and to reduce the temperature of the combustion gas in the sub-chamber 2, and still in the main chamber 1. An object of the present invention is to provide a combustion chamber of a sub-chamber type internal combustion engine that can suppress a rapid rise in the combustion gas temperature and can reduce the generation of NOx. A combustion chamber of a sub-chamber internal combustion engine according to the present invention is an internal combustion engine in which a sub-chamber 2 is formed in a sub-chamber mouthpiece 8 mounted on a cylinder head 4, and the sub-chamber 2 is formed on the outer peripheral surface of the sub-chamber mouthpiece. Is formed with a trapezoidal screw portion 204 having a lead in the axial direction, and a sub-room cooling water chamber 200 having a spiral cooling water flow path is formed between the sub-chamber mounting hole of the cylinder head 4 and the sub-chamber cooling water. In order to circulate the cooling water in the chamber, a cooling water supply channel 201 is bored in the sub chamber mouthpiece, and a cooling water return channel 202 is bored in the cylinder head 4 to form a cooling chamber type sub chamber with cooling water. It is characterized by being configured.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a combustion chamber of a sub-chamber internal combustion engine.

[0002]

[Prior art]

 FIG. 2 shows a vertical cross-sectional view of a combustion chamber of a conventional sub-chamber (cooling structure) internal combustion engine. Next, the configuration will be described with reference to FIG. The sub-combustion chamber 2 is arranged in the cylinder head 4, and its shape is basically a columnar shape with the center line BB. The fuel injection valve 5 is mounted from the upper part to assist the cold start of the engine. Therefore, a glow plug (not shown) that preheats the sub combustion chamber 2 is installed if necessary. The sub-combustion chamber 2 communicates with the main combustion chamber 1 through sub-chamber injection holes 3 formed in the tip of the sub-chamber mouthpiece 8 at equal intervals. Further, a cutout groove is provided in the outer peripheral portion of the sub-chamber mouthpiece 8 to form a sub-chamber cooling water chamber 200 between the sub-chamber mouthpiece mounting hole of the cylinder head 4 and the sub-chamber mouthpiece 8 in the cooling water chamber. A cooling water supply channel 201 and a cooling water return channel 202 communicate with each other from above. In addition, in order to seal the leakage of the cooling water, the sub-chamber base 8 is attached to the cylinder head 4 by inserting O-rings 203 at the upper end and the lower end.

Next, the operation of the above-mentioned conventional example will be described. (Hereinafter, the main combustion chamber is abbreviated as the main chamber, and the sub combustion chamber is abbreviated as the sub chamber.) During the compression stroke, the air in the main chamber 1 is compressed by the rise of the piston 6 and enters the sub chamber 2 through the sub chamber injection port 3. Inflow. Fuel is injected from the fuel injection valve 5 into the sub-chamber 2 to burn a part of the fuel, and the rise in temperature and pressure accompanying this is used to spray unburned fuel with the burned gas from the sub-chamber injection port 3. It is jetted into the main chamber 1 to burn all the fuel. At this time, the temperature of the gas on the inner wall surface and the outer peripheral surface of the sub-chamber mouthpiece 8 also rises due to the rise in the gas temperature accompanying the combustion in the sub-chamber 2. For this reason, the cooling water whose temperature and flow rate have been adjusted in advance is supplied from the water supply passage 201 to the sub-chamber cooling water chamber 200 and recirculated through the return water passage 202 to cool the outer peripheral surface of the sub-chamber base 8. The heat in the sub-chamber 2 is returned to the cooling water through the wall surface of the sub-chamber mouthpiece 8, and a rapid increase in the gas temperature in the sub-chamber 2 is suppressed.

[0004]

[Problems to be solved by the device]

 However, the above-mentioned conventional combustion chamber of the sub-chamber internal combustion engine has the following problems. That is, as shown in FIG. 2, since the structure of the sub-chamber cooling water chamber 200 is cylindrical and the cooling water supply passage 201 and the return water passage 202 are adjacent to each other, the supplied cooling water is the sub-chamber cooling water. In the upper part of the chamber 200, since it circulates around the return water inlet part from the water supply outlet part of the water supply channel 201 to the return water channel 202, it is difficult to reach the lower part of the sub chamber cooling water chamber 200. It was not possible to evenly and efficiently cool the outer peripheral surface of the. For this reason, it becomes difficult to efficiently lower the combustion gas temperature in the sub chamber 2 by the heat flow through the wall surface of the sub chamber mouthpiece 8, and it has been impossible to reduce the generation of NOx.

The object of the present invention is to solve the above problems, to lower the temperature of the combustion gas in the sub-chamber 2, and to prevent the combustion gas temperature in the main chamber 1 from rising sharply. The purpose of the present invention is to provide a combustion chamber of an internal combustion engine of a sub-chamber type, which can suppress NOx generation in the main chamber 1 and the sub-chamber 2.

[0006]

[Means for Solving the Problems]

 The combustion chamber of the sub-chamber internal combustion engine according to the present invention is an internal combustion engine in which the sub-combustion chamber 2 is formed inside the sub-chamber mouthpiece 8 mounted on the cylinder head 4, and the sub-chamber portion of the sub-chamber mouthpiece has an outer peripheral surface. A trapezoidal screw portion 204 having a lead in the axial direction of the sub-chamber base is provided, and a sub-chamber cooling water chamber 200 is formed between the trapezoidal screw portion and a lower portion of the mounting hole of the sub-chamber base provided in the cylinder head 4. In order to circulate the cooling water in the sub-chamber cooling water chamber, a cooling water supply passage 201 penetrating from the upper surface of the sub-chamber base to the upper portion of the sub-chamber cooling water chamber is bored in the sub-chamber base, and The cylinder head 4 is provided with a cooling water return passage 202 penetrating from the bottom of the sub-chamber cooling water chamber to the upper surface of the cylinder head to form a sub-combustion chamber 2 of a cooling structure for cooling the outside with water. It is characterized by that.

[0007]

[Action]

 Since the present invention has the above-mentioned configuration, it operates as follows. Since the trapezoidal screw portion 204 is provided on the outer peripheral surface of the sub-chamber portion of the sub-chamber base 8, the cooling specific surface area is large, and water is supplied into the sub-chamber cooling water chamber 200 via the cooling water supply passage 201. The cooling water spirally swirls in the sub-chamber cooling water chamber using the thread groove of the trapezoidal screw portion 204 on the outer peripheral surface of the sub-chamber base 8 as a flow path, and reaches the lower equivalent portion of the sub-chamber 2. To the bottom of the cooling water chamber, flows upward in the cooling water return water passage 202 and returns to the outside, and circulates and cools the outer peripheral surface of the sub chamber of the sub chamber mouthpiece. The heat generated by the combustion in the sub-chamber 2 due to the circulation of the cooling water efficiently passes through the wall surface of the sub-chamber mouthpiece 8 to the cooling water, so that the combustion gas temperature in the sub-chamber 2 should be lowered efficiently. In addition, a rapid rise in the combustion gas temperature in the main chamber 1 is suppressed, and the generation of NOx in the main chamber 1 and the sub chamber 2 can be reduced.

[0008]

【Example】

 An embodiment of the present invention will be described with reference to FIG. The figure shows a vertical sectional view of a combustion chamber of a sub-chamber diesel engine of the present invention. 1 is a main (combustion) chamber, 2 is a sub (combustion) chamber, 3 is a sub chamber injection port, 4 is a cylinder head, 5 is a fuel injection valve, 6 is a piston, 7 is a cylinder liner, 8 is a sub chamber mouthpiece, and 200 is Sub-chamber cooling water chamber, 201 cooling water supply channel, 202 cooling water return channel, 203 O-ring, 204 trapezoidal screw part, AA is cylinder center line, BB is sub chamber center line. . The structure of the combustion chamber composed of the main chamber 1 and the auxiliary chamber 2 of the pre-combustion chamber type, and the positions and mounting relations of the cylinder head 4, the cylinder liner 7, the piston 6, the fuel injection valve 5 and the like are the same as in the conventional example. In the present invention, a trapezoidal screw portion 204 having a lead in the direction of the center line BB of the sub chamber base is provided on the outer peripheral surface of the sub chamber base of the sub chamber base 8, and the center line B of the sub chamber base from the upper surface of the cylinder head 4 is provided. -Fix by screwing into the sub chamber mouthpiece mounting hole that is bored with B as the axis. As a result, a sub-chamber cooling water chamber 200 is formed between the trapezoidal screw portion at the lower portion of the sub-chamber mouthpiece 8 and the portion below the mouthpiece mounting screw portion of the sub-chamber mouthpiece mounting hole. In order to circulate the cooling water in the sub-chamber cooling water chamber, the sub-chamber base 8 is provided with a cooling water supply passage 201 penetrating from the upper surface to the upper portion of the sub-chamber cooling water chamber, and Has a cooling water return water passage 202 penetrating from the bottom of the cooling water chamber to the upper surface of the cylinder head. An O-ring 203 is fitted to the upper end and the lower end of the sub-chamber base 8 in order to seal the leakage of the cooling water.

Next, the operation of the above configuration will be described. The cooling water supplied into the sub-chamber cooling water chamber 200 through the cooling-water supply passage 201 spirals in the sub-chamber cooling water chamber with the thread groove of the trapezoidal screw portion 204 on the outer peripheral surface of the sub-chamber base 8 as a flow path. Flowing in a swirling manner, reaching the lower equivalent part of the sub-chamber 2 and then reversing the direction of the flow at the bottom of the cooling water chamber, and upward in the cooling water return water channel 202 communicating with the bottom of the cooling water chamber. It flows back to the outside, and the outer peripheral surface of the sub-chamber part of the sub-chamber mouth becomes a circulating flow to efficiently and evenly cool. By providing the trapezoidal screw portion 204, the cooling specific surface area of the sub-chamber base 8 is increased, so that the cooling effect is also improved. Due to the circulation flow of the cooling water passing through the sub-chamber cooling water chamber 200, the combustion heat generated in the sub-chamber 2 passes through the wall surface of the sub-chamber mouthpiece 8 and efficiently penetrates into the cooling water. It is possible to efficiently reduce the combustion gas temperature in the main chamber 1, and as a result, the rapid increase in the combustion gas temperature in the main chamber 1 is suppressed, and the combustion chamber temperature in the main chamber 1 and the sub chamber 2 is reduced. Generation of NOx can be reduced.

[0010]

[Effect of device]

 Since the present invention is constructed as described above, the following effects can be obtained. The outer peripheral surface of the sub chamber portion of the sub chamber mouth 8 is evenly and efficiently cooled, and the heat and heat of heat generated in the sub chamber 2 is passed through the wall surface of the sub chamber mouth 8 to the circulating cooling water. Therefore, the combustion gas temperature in the sub-chamber 2 can be efficiently lowered, and the combustion gas temperature ejected from the sub-chamber 2 to the main chamber 1 is suppressed to a low level, so that the combustion in the main chamber 1 is suppressed. It is also possible to suppress a sharp rise in gas temperature. Therefore, the generation of NOx in the main chamber 1 and the sub chamber 2 can be reduced.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of a combustion chamber of a sub-chamber internal combustion engine according to an embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view of a combustion chamber of a subchamber internal combustion engine according to the related art.

[Explanation of symbols]

1 ... Main (combustion) chamber, 2 ... Sub (combustion) chamber, 3 ... Sub chamber injection port,
4 ... Cylinder head, 5 ... Fuel injection valve, 6 ... Piston,
7 ... Cylinder liner, 8 ... Sub chamber mouthpiece, 200 ... Sub chamber cooling water chamber, 201 ... Cooling water supply channel, 202 ... Cooling water return channel,
203 ... O-ring, 204 ... Trapezoidal screw portion, AA ... Cylinder center line, BB ... Sub chamber center line.

Claims (1)

[Scope of utility model registration request] 1. In an internal combustion engine in which a sub-combustion chamber (2) is formed inside a sub-chamber mouthpiece (8) mounted on a cylinder head (4), the sub-chamber mouthpiece is formed on the outer peripheral surface of the sub-chamber mouthpiece. A trapezoidal screw part (204) having a lead in the axial direction is provided,
The sub chamber cooling water chamber (200) is provided between the trapezoidal screw portion and the lower portion of the mounting hole of the sub chamber mouthpiece provided in the cylinder head (4).
And a cooling water supply passage (201) is formed in the sub-chamber cap so as to circulate the cooling water in the sub-chamber cooling water chamber from the upper surface of the sub-chamber base to the upper portion of the sub-chamber cooling water chamber. In the cylinder head (4), the cooling water return passage (2) that penetrates from the bottom of the sub chamber cooling water chamber to the upper surface of the cylinder head is provided.
02) is provided to form a sub-combustion chamber (2) of a cooling structure in which the outside is cooled with water, and the combustion chamber of the sub-chamber internal combustion engine.