JPH056126U - Internal combustion engine cylinder head - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a cylinder head of an internal combustion engine having a simple structure and capable of reducing the amount of hydrocarbons in exhaust gas. [Structure] A cylinder head of an internal combustion engine is a combustion chamber
8, an intake port 20 and an exhaust port 22 opening to the combustion chamber 18, and a head bottom surface 1 of the cylinder head.
6 and a groove 32 formed in a region of the squish surface 30 on the intake port 20 side close to the intake port 20.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an internal combustion engine for an automobile, and more particularly to a cylinder head for an internal combustion engine.

[0002]

[Prior Art]

 In recent years, in order to improve its output performance, internal combustion engines for automobiles are mainly equipped with two intake / exhaust valves per cylinder and a high compression ratio of the air-fuel mixture. .. In order to increase the compression ratio of the mixing ratio, it is necessary to project the top surface of the piston or reduce the size of the combustion chamber itself, but generally, a large squish area is secured and the combustion chamber itself is made small. The internal combustion engine is often used.

[0003]

[Problems to be solved by the device]

 By the way, as mentioned above, when the squish area becomes large, it becomes difficult for the flame to enter deep inside the squish area in the explosion stroke or combustion stroke of the internal combustion engine, and as a result, unburned gas is generated and carbonization occurs in the exhaust gas. There is a problem that the amount of hydrogen increases.

Such a problem becomes particularly noticeable when the internal combustion engine is in a cold state and the amount of fuel flowing from the intake port to the squish area along the wall surface of the combustion chamber increases. The present invention has been made based on the above-mentioned circumstances, and an object thereof is to provide a cylinder head of an internal combustion engine capable of reducing the amount of hydrocarbons in exhaust gas.

[0005]

[Means for Solving the Problems]

 The cylinder head of an internal combustion engine of the present invention comprises a cylinder head body, a combustion chamber formed on the cylinder block side head bottom surface of the cylinder head body, and an intake air chamber formed in the cylinder head body and opening in the combustion chamber. A squish surface that is provided around the combustion chamber opening edge on the bottom surface of the head and the exhaust port and defines the squish area between the piston and the top surface of the piston when the piston is at top dead center. A groove formed near the intake port is provided in a region of the surface on the intake port side.

[0006]

[Action]

 According to the cylinder head of the internal combustion engine described above, particularly when the internal combustion engine is in a cold state, the fuel that tries to enter the squish area from the intake port through the wall surface of the combustion chamber is guided by the groove formed on the squish surface. However, the inflow route is blocked, and the fuel does not enter deep inside the squish area.

[0007]

【Example】

 Referring to FIG. 1, an internal combustion engine for a motor vehicle is schematically shown. The internal combustion engine includes a cylinder block 2, and a cylinder bore 2 is formed in the cylinder block 2. A piston 8 is slidably fitted in the cylinder bore 4 via a liner 6. Although not shown, the piston 8 is connected to the crankshaft via a connecting rod.

A cylinder head 12 is coupled to the cylinder block 2 via a gasket 10. The cylinder head 12 includes a cylinder head body 14, and a combustion chamber 18 is formed on a bottom surface 16 of the cylinder head body 14 on the cylinder block 2 side. As shown in FIG. 2, the combustion chamber 18 has two intake ports 20 and two exhaust ports 22. When the combustion chamber 18 is divided by the plane P including the axis of the cylinder bore 4, the intake port 20 and the exhaust port 22 are located in the regions on one side, respectively.

The intake port 20 and the exhaust port 22 can be opened and closed by an intake valve 24 and an exhaust valve 26, respectively, and a spark plug 28 is attached to the top of the combustion chamber 18. The opening edge of the combustion chamber 18 is much smaller than the top surface of the piston 8 and thus when the pistunt 8 is at top dead center, as shown in FIG. A squish area SA is provided between and.

A groove 32 is formed on the intake port 20 side on a portion of the head bottom surface 16 that defines the squish area SA, that is, on the squish surface 30 around the opening edge of the combustion chamber 18. There is. As is apparent from FIG. 2, the groove 32 extends from one intake port 20 to the other intake port 20 along the above-mentioned plane P, and the edge of the groove 32 on the combustion chamber 18 side is , Fuel cut edge 34.

When the squish surface 30 has a margin, the groove 32 may be formed so as to surround two intake ports, as shown by the broken line in FIG. If the above-described groove 32 is formed in the squish surface 30, even if liquid fuel is guided from the intake port 20 to the squish surface 30 along the wall surface of the combustion chamber 18, the fuel inflow path is Since it is blocked by the cutting edge 34, the fuel does not flow into the deep part of the squish area SA. Therefore, in the combustion process of the internal combustion engine, even if the flame does not enter the squish area SA well, the fuel does not enter the squish area SA beyond the groove 32, so the combustion of the fuel is reliable. As a result, the generation of unburned gas can be suppressed and the amount of hydrocarbons in the exhaust gas can be greatly reduced. Such an effect of reducing the amount of hydrocarbon becomes particularly remarkable when the internal combustion engine is in a cold state in which the fuel dripping from the intake port 20 is difficult to vaporize.

The effect of reducing the amount of hydrocarbons due to the presence of the groove 32 is also shown in FIG. In FIG. 3, the solid line shows the case of the internal combustion engine having the groove 32, that is, the case of the cylinder head, and the broken line shows the case of the conventional cylinder head having no groove 32. At the time t1, the internal combustion engine is changed from the cranking state. It shows the time when the ignition is started. As is apparent from FIG. 3, in the case of the internal combustion engine equipped with the cylinder head with the groove 32, the amount of hydrocarbons in the exhaust gas is reduced as compared with the conventional internal combustion engine. Figure 3 shows the experimental results at room temperature of 25 ° C, but the effect becomes more remarkable when the temperature is lower.

The present invention is not limited to the above-described embodiment, and various modifications can be made. For example, in one embodiment, the cylinder head is provided with two intake ports and two exhaust ports, but the number of these intake ports and exhaust ports is not limited to that of the one embodiment, and is not limited. Need only have a groove on the squish surface on the intake port side close to the intake port. Therefore, in one embodiment, one common groove 32 is formed for two intake ports, but this groove 32 may be separated for each intake port.

[0014]

[Effect of the device]

 As described above, according to the cylinder head of the internal combustion engine of the present invention, it is easy to provide a groove that forms a pair with the intake port on the squish surface of the cylinder head that defines the squish area, close to the intake port. With this structure, the liquid fuel that is trying to enter the squish area from the intake port through the wall of the combustion chamber is blocked by the groove in the inflow path, and as a result, reaches the inner part of the squish area. Liquid fuel does not flow in. Therefore, it has an excellent effect of suppressing the generation of unburned gas and reducing the amount of hydrocarbons in the exhaust gas.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of an internal combustion engine including a cylinder head according to an embodiment.

FIG. 2 is a bottom view showing a part of the cylinder head of FIG.

FIG. 3 is a graph showing the amount of hydrocarbons in exhaust gas when the internal combustion engine is started.

[Explanation of symbols]

 8 Piston 14 Cylinder Head Body 18 Combustion Chamber 20 Intake Port 22 Exhaust Port 30 Squish Surface 32 Groove

Claims (1)

[Claims for utility model registration] 1. A cylinder head main body, a combustion chamber formed on the bottom surface of the cylinder head main body on the cylinder block side, and a cylinder head main body formed in the combustion chamber, each opening in the combustion chamber. A squish surface that is provided around the intake port and exhaust port, and around the edge of the combustion chamber opening on the bottom surface of the head, and that defines the squish area between the piston and the top surface when the piston is at top dead center. A cylinder head for an internal combustion engine, comprising: a groove formed in the region of the surface on the intake port side in the vicinity of the intake port.