JPH04125628U - Combustion chamber of internal combustion engine - Google Patents

Abstract

(57) [Summary] [Purpose] To improve combustion in an internal combustion engine that generates so-called tumble flow in the combustion chamber. [Structure] A squish area 21 that protrudes toward the piston is provided between the intake valves 12 and 13 on the top surface of the combustion chamber, and when the piston rises, the squish is compressed between the piston and the squish area 21 and pushed out to the side. The flow actively stirred the tumble flow to reduce the scale of turbulence.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This invention is a combustion chamber of an intake two-valve engine that forms a tumble flow (vertical swirl). Regarding improvements.

0002

[Conventional technology]

In an internal combustion engine, a rich air-fuel mixture and air are supplied into the combustion chamber in layers to produce combustion. Efforts have been made to improve the firing process. In other words, by igniting a rich mixture, This enables combustion even if the overall air-fuel mixture is lean. This not only improves engine fuel efficiency, but also reduces harmful engine emissions. It can also effectively prevent engine knocking. .

0003 In order to achieve the above combustion, there is a layer of rich mixture and air or lean air in the combustion chamber. The combustion chamber shown in Figure 4 has been considered as a combustion chamber that clearly forms a layer of air-fuel mixture. There is.

0004 In Fig. 4, 1 is the cylinder bore, 2 is the piston therein, and 3 is the cylinder head. The combustion chamber 4 is partitioned by these sections. Combustion chamber of cylinder head 3 Two intake ports 6 and 7 are provided on the slope of one side of the pent roof 5 that forms the top surface of the roof 4. are each opened. The intake ports 6 and 7 have introduction passages 8 and 9 parallel to each other. are connected to each other. Inlet passages 8, 9 Intake manifold not shown It is connected to the. Although not shown in the drawings, the intake ports 6 and 7 have intake valves, respectively. In addition, a fuel injection valve 10 is provided in one of the introduction passages 9. Ru.

[0005] Although not shown, there are exhaust ports and exhaust valves on the other slope of the pent roof 5. is provided. Note that 11 in the figure is a spark plug.

[0006] In the above combustion chamber, the air is introduced from the introduction passages 8 and 9 and the intake ports 6 and 7, respectively. The air and mixture are guided to the inner wall of the cylinder bore 1 and are vertically swirled. It becomes a tumble style (parel swirl style). Therefore, first, check the rich mixture tumbler. By igniting the tumble flow of lean mixture, even the tumble flow of lean mixture can be combusted effectively. This makes stratified combustion possible. In addition, the increase in the flow velocity of the strong tumble flow It also promotes the combustion of aiki. This results in a rich and lean mixture. Stable combustion is possible even if the overall air-fuel ratio is higher than the stoichiometric air-fuel ratio. be.

[0007]

[Problem that the idea aims to solve]

However, even with the above structure, extremely lean operating conditions or lean conditions Under operating conditions with extensive exhaust gas recirculation (EGR), the laminar combustion rate is low. It has been confirmed that combustion stability is impaired by

[0008]

[Means to solve the problem]

In this invention, in order to solve the above problems, we first analyzed combustion in the combustion chamber. Pi When the stone rises and approaches the ignition timing, the tumble flow is crushed and becomes turbulent. However, the characteristics of this disturbance are strong but large-scale (the formation of the disturbance vortex diameter).

[0009] If the laminar combustion rate is not very low, there is no harm caused by large scale. Although it does not appear, this adverse effect becomes noticeable when the laminar combustion velocity decreases significantly.

0010 Therefore, in this invention, we have developed a skid that protrudes on the top surface of the combustion chamber of an internal combustion engine toward the piston. They formed Shueria.

[0011]

[Effect]

In the above combustion chamber, the tumble flow is crushed and turbulent by the rise of the piston. When this occurs, it is compressed between the piston and the squish area and the side, that is, the combustion The squish flow that protrudes toward the center of the baking chamber actively stirs up turbulence and reduces scale. Write down.

0012

【Example】

Figure 1 shows a combustion chamber according to an embodiment of the present invention viewed from diagonally below, and Figure 2 Figure 2 shows a schematic cross-section of the combustion chamber. Pipe forming the top surface of the combustion chamber 4 of the cylinder head 3 Intake ports 6 and 7 are formed on one slope of the engine roof 5, and an intake valve 12 is connected thereto. , 13 are provided, respectively. Intake passages 8 and 9 are connected to intake ports 6 and 7. has been done. Exhaust ports 14 and 15 are formed on the other slope of the pent roof 5. Exhaust valves 16 and 17 are provided there respectively, and exhaust ports 14 and 15 are provided with exhaust valves 16 and 17, respectively. Exhaust passages 18 and 19 are connected. In the figure, 20 is the mounting hole for the spark plug. .

[0013] Between the two intake ports 6 and 7, the pent roof 5 has a downward (piston) A squish area 21 is provided in a raised manner on the front side). squish area 21 may also be provided between the exhaust ports 14 and 15. Squish area 21 is a cylinder It is integrally molded with the head 3.

[0014] In this combustion air structure, as shown in Fig. 3, when the piston 2 rises, , the air-fuel mixture compressed between the piston 2 and the squish area 21 flows into a squish flow. and jumps out to the center side of the combustion chamber, and this squish flow FS causes a tumble flow F. is actively stirred, and the scale of disturbance is reduced. Therefore, the laminar burning rate Under extremely lean conditions or high EGR conditions under lean conditions, combustion becomes stable.

[0015] Combustion improvement is achieved by reducing the scale of turbulence, that is, the mixture swirl. The surface area for the flame propagation of the mixture vortex increases, and the flame propagation area in the mixture vortex increases. The spread of flame will also be accelerated.

[0016]

[Effect of the idea]

According to the combustion chamber according to the present invention, the scale of turbulence in tumble flow is replaced by squish flow. By actively stirring and reducing the size, combustion is improved and lean fuel is produced. It is possible to stabilize the combustion in the state.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a combustion chamber according to an embodiment, viewed diagonally from below.

FIG. 2 is a schematic cross-sectional view of a combustion chamber according to one embodiment.

FIG. 3 is a schematic cross-sectional view illustrating the operation of the embodiment.

FIG. 4 is a schematic perspective view of an example of a combustion chamber that generates a tumble flow.

[Explanation of symbols]

1 Cylinder bore 2 piston 3 Cylinder head 4 Combustion chamber 5 Pent roof 6,7 Intake port 10 Combustion injection valve 11 Spark plug 12,13 Intake valve 21 Scache area

Claims (1)

[Scope of utility model registration request] Claim 1: In a combustion chamber of an internal combustion engine that is configured to generate a swirling flow flowing in the axial direction of a cylinder bore within the combustion chamber, a squish area that is raised toward the piston side is provided on the top surface of the combustion chamber. Characteristic combustion chamber.