PISTON COMBUSTION CHAMBER STRUCTURE OF ENGINE

Abstract

A piston combustion chamber structure of an engine includes two or more independent combustion chambers separated from each other and dented on an upper portion of a piston head in axial and circumferential directions. Each of the two or more independent combustion chambers comprises an outer wall and a bottom surface. Independent combustion chambers adjacent to each other among the two or more independent combustion chambers are partitioned by a partition wall. The partition wall has a slant surface such that a squish flowing in the circumferential direction can be generated.

Claims

1. A piston combustion chamber structure of an engine, comprising: two or more independent combustion chambers separated from each other and dented on an upper portion of a piston head in axial and circumferential directions, wherein each of the two or more independent combustion chambers comprises an outer wall and a bottom surface, wherein independent combustion chambers adjacent to each other among the two or more independent combustion chambers are partitioned by a partition wall, and wherein the partition wall has a slant surface such that a squish flowing in the circumferential direction can be generated.

2. The piston combustion chamber structure of claim 1, wherein each of the outer wall and the bottom surface has a curved surface.

3. The piston combustion chamber structure of claim 2, wherein the curved surface has a cross section of a circular arc shape or an elliptical shape.

4. The piston combustion chamber structure of claim 1, wherein a pip portion in a center of the bottom surface protrudes in a height direction of the piston head.

5. The piston combustion chamber structure of claim 4, wherein a height of the bottom surface gradually decreases from the pip portion toward an outside in a radial direction.

6. The piston combustion chamber structure of claim 1, wherein a height of the partition wall is lower than an upper surface of the piston head.

7. The piston combustion chamber structure of claim 1, wherein a maximum depth from an upper surface of the piston head to the bottom surface is greater than and less than three times a maximum depth from the upper surface of the piston head to the partition wall.

8. The piston combustion chamber structure of claim 1, wherein the partition wall is provided in plural, and wherein a maximum width of each of the two or more independent combustion chambers is less than of a gap between the partition walls.

9. The piston combustion chamber structure of claim 1, wherein the partition wall is provided in plural, and wherein a width of the bottom surface is equal to or less than of a gap between the partition walls.

10. The piston combustion chamber structure of claim 1, wherein an exterior diameter of each of the two or more independent combustion chambers is larger than and smaller than 1.5 times an exterior diameter of the partition wall.

11. The piston combustion chamber structure of claim 1, wherein the partition wall is provided in plural, and wherein an expansion width of each of the two or more independent combustion chambers extending radially outward from an end portion of the partition wall is equal to or less than of a gap between the partition walls.

12. The piston combustion chamber structure of claim 1, wherein the partition wall has a spiral shape.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] FIG. 1 is a perspective view of a piston combustion chamber structure of an engine according to an exemplary embodiment of the present disclosure;

[0026] FIG. 2 is a top plan view of the piston combustion chamber structure of the engine according to the exemplary embodiment of the present disclosure;

[0027] FIG. 3 is a cross-sectional view taken along A-A line of FIG. 2;

[0028] FIG. 4 is a cross-sectional view taken along B-B line of FIG. 2;

[0029] FIG. 5 is a perspective view showing a process of injecting fuel into the piston combustion chamber structure of the engine according to the exemplary embodiment of the present disclosure; and

[0030] FIG. 6 is a perspective view of a piston combustion chamber structure of an engine according to another exemplary embodiment of the present disclosure.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0031] Hereinafter, exemplary embodiments of the present disclosure will be described in detail with reference to accompanying drawings.

[0032] Referring to FIGS. 1 to 4, a piston combustion chamber structure of an engine according to an exemplary embodiment of the present disclosure may include a plurality of independent combustion chambers 10 dented in an axial direction and a circumferential direction on an upper portion of a piston head 1 reciprocating vertically.

[0033] Each independent combustion chamber 10 may include a curved outer wall 12 forming an outer wall of the combustion chamber and a substantially funnel-shaped bottom surface 13 forming the bottom of the combustion chamber 10, respectively, and an upper portion of each independent combustion chamber 10 is configured to be opened.

[0034] The curved outer wall 12 may have a circular arc shape or a cross-section of an elliptical shape. The bottom surface 13 may be a curved surface of a circular arc shape or an elliptical shape.

[0035] A cylinder head (not shown) is fastened to a cylinder block (not shown) above the piston head 1 so that the upper portion of each independent combustion chamber 10 can be closed and sealed by the cylinder head.

[0036] Further, the cylinder head may be equipped with an intake port for flowing outside air into the independent combustion chamber 10 and an exhaust port for exhausting the exhaust gas combusted in the combustion chamber.

[0037] The beginning portion (the center of fuel injection) of the bottom surfaces 13 of each independent combustion chamber 10, that is, a pip portion 14 is formed in a shape having a predetermined height by protruding in the height direction of the piston head 1. The pip portion 14 may have a shape gradually decreasing in height from the bottom surface 13 of the independent combustion chamber 10 toward the outer radial direction.

[0038] That is, the height of the bottom surface 13 of each independent combustion chamber 10 is the highest at the pip portion 14 and gradually decreases toward the outer wall 12 so that the portion adjacent to the outer wall 12 is the lowest.

[0039] A partition wall 15 may protrude in the direction of an upper surface 1a of the piston head 1 in order to separate each independent combustion chamber 10.

[0040] The height of the partition 15 may be lower than the upper surface 1a of the piston head 1.

[0041] Further, the partition 15 may have a slant surface so that a squish flowing in a circumferential direction can be generated. The term squish can be understood by one of ordinary skill in the art as an effect in internal combustion engines which creates sudden turbulence of the fuel/air mixture as the piston approaches top dead centre (TDC).

[0042] Each independent combustion chamber 10 can be separated along the circumferential direction with the partition 15 therebetween.

[0043] In the exemplary embodiment of the present disclosure, although each independent combustion chamber 10 is shown as six, it is only one exemplary embodiment corresponding to the number of fuel injection holes of the injector, and may be formed by two or more numbers.

[0044] The maximum depth h of the bottom surface 13 from the top surface of the piston head 1 may be greater than the maximum depth H of the partition wall 15 from the top surface of the piston head 1 and less than three times the maximum depth H of the partition wall 15.

[0045] That is, the maximum depth h of the bottom surface 13 may be H<h<3H in consideration of the durability of the piston.

[0046] Further, the maximum width W of the independent combustion chamber 10 may be less than of the gap L between the partition walls 15 in consideration of the injection angle of the injector nozzle (W<0.5L).

[0047] Further, the width of the bottom surface 13 may be equal to or less than of the gap L between the partition walls 15.

[0048] An exterior diameter D1 of the independent combustion chamber 10 may be larger than an exterior diameter D of the partition wall 15 and less than 1.5 times of the exterior diameter D of the partition wall 15 in order to minimize the heat loss of the combustion gas (D<D1<1.5D).

[0049] Additionally, the expansion width W1 of the independent combustion chamber 10 extending radially outward from the end portion of the partition wall 15 may be less than of the gap L between the partition walls 15 and the extension width W1 may be determined in consideration of the fuel injection angle of the injector and heat transfer minimization simultaneously.

[0050] In accordance with the combustion chamber structure according to an exemplary embodiment of the present disclosure as described above, as shown in FIG. 5, fuel 30 is injected from the injector into the combustion chamber space formed in each independent combustion chamber 10, and the injected fuel is mixed with air only in each independent combustion chamber 10 and combusted. Fuel 30 injected into each independent combustion chamber 10 is blocked by the partition wall 15 and is not likely to be mixed with each other, so that the combust efficiency can be improved and the incomplete combustion can be prevented.

[0051] As a result, it is possible to eliminate the incomplete combustion caused by the superimposition of the fuel that is reflected after the conventional fuel injection, and to improve the enhancement of fuel efficiency and reduce harmful exhaust gas.

[0052] On the other hand, referring to FIG. 6, when the air flowing into each independent combustion chamber through the intake port of the cylinder head is subjected to a strong swirl flow, partition walls 25 may be formed in a spiral shape.

[0053] While this disclosure has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the disclosure is not limited to the disclosed embodiments. On the contrary, it is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.