OIL JET FOR INTERNAL COMBUSTION ENGINE AND PISTON COOLING DEVICE FOR INTERNAL COMBUSTION ENGINE
An oil jet (23) has an injection nozzle (32) that injects engine oil supplied from an oil supply passage of the internal combustion engine toward a piston. The injection nozzle (32) has a first pipe (36) having a supply port (35) communicating with an oil supply passage side and a second pipe (38) having an injection orifice (37) that injects the engine oil. The first pipe (36) and second pipe (38) are joined together with their axes forming a predetermined angle. The injection orifice (37) is formed such that a cross section of the injection orifice (37) is greater than a minimum radial direction cross section of the first pipe (36).
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The present invention relates to an improvement in an oil jet for an internal combustion engine and a piston cooling device for the internal combustion engine.
BACKGROUND ARTAs is known, an oil jet of an internal combustion engine is an oil jet that reduces a temperature of a piston by jetting or spraying engine oil to a back surface side of the piston, increases strength of the piston, ensures reliability of the piston and reduces an engine knocking.
In order to contribute to recent improvement in fuel efficiency of the internal combustion engine, reduction in size and increase in energy efficiency of an oil pump that produces pressure of the engine oil and reduction in supply amount of the engine oil to the oil jet are desired, and there is a need to perform efficient heat exchange with a small amount of oil. Here, a general conventional oil jet is configured to linearly inject or spray the oil with an oil flow velocity increased by a structure in which a tip end of an injection orifice side is narrowed or squeezed. Because of this, jet (injection flow) of the oil has a high linearity, and a jet diameter (an injection flow diameter) of the oil is about a diameter of a nozzle tip end, then cooling is locally performed. It is therefore impossible to efficiently cool the entire piston.
Thus, Patent Document 1 has disclosed various shapes of a tip end portion of the oil jet and a technique of controlling a shape of the jetted oil (the injected oil). Further, Patent Document 2 has proposed a structure in which a spiral groove is formed on a pipe inner surface of the oil jet.
CITATION LIST Patent Document
- Patent Document 1: Japanese Unexamined Utility Model Application Publication No. JIKKAIHEI 4-105935 (JPH04-105935U)
- Patent Document 2: Japanese Unexamined Utility Model Application Publication No. JIKKAISHO 50-52341 (JPU11975-052341)
In Patent Document 1, however, forming the various shapes of a nozzle tip end of the oil jet causes increase in manufacturing man-hours and manufacturing cost. In Patent Document 2, it is extremely technically difficult to form the spiral groove on a curved pipe inner surface of the oil jet, and this also increases manufacturing man-hours and manufacturing cost.
An object of the present invention is therefore to provide a new oil jet for an internal combustion engine and a new piston cooling device for the internal combustion engine, which can be formed by easy manufacturing and process and is capable of widely injecting or spraying the engine oil with a high cooling effect.
Solution to ProblemThe present invention relates to an oil jet for an internal combustion engine as a cooling device that is provided inside the internal combustion engine and injects or sprays the oil toward a back surface side of a piston. The oil jet comprises an injection nozzle that injects the oil supplied from an oil supply passage of the internal combustion engine toward the piston. The injection nozzle has a first pipe communicating with the oil supply passage and a second pipe having an injection orifice that injects the oil. The first and second pipes being joined together with axes of the first and second pipes forming a predetermined angle. The injection orifice is formed such that a cross section of the injection orifice is greater than a minimum radial direction cross section of the first pipe.
Effects of InventionAccording to the present invention, it is possible to widely inject or spray the engine oil and greatly increase cooling efficiency although the manufacturing and process are easy.
In the following description, an oil jet for an internal combustion engine and a piston cooling device for the internal combustion engine according to the present invention will be explained with reference to drawings.
As shown in
As shown in
The cylinder block 10 is provided with an oil jet 23 as a cooling device of the internal combustion engine. This oil jet 23 has the function of cooling the piston 12 by injecting or spraying and supplying the engine oil toward a back surface side of the piston 12. The oil jet 23 is connected and secured to a mounting surface 24 at a lower end of the cylinder liner 11 with a fixing bolt 25 so as not to interfere with the connecting rod 20 and the crankshaft.
The cylinder block 10 is further provided with an oil supply passage 26 to supply the engine oil to an oil supply portion including the oil jet 23. The engine oil stored in an oil pan disposed at a lower side of the internal combustion engine is pressurized by an oil pump, and supplied to the oil jet 23, lubrication parts and hydraulic devices and so on through the oil supply passage 26, although these are not illustrated in the drawings.
As a representative structure of the oil jet 23, a die-cast type as shown in
As is known, the check ball is forced in a direction that closes the oil supply passage 26 by a spring, which is not illustrated in the drawings, and by the fact that pressure of the engine oil in the oil supply passage 26 (in a main gallery) exceeds a set load of the spring, the engine oil is supplied to the oil jet 23. That is, when the pressure of the engine oil supplied to the oil supply passage 26 of the internal combustion engine is equal to or greater than a predetermined value, the engine oil spontaneously jets. As described later, the engine oil flowing into the oil jet 23 is injected or sprayed and supplied to the back surface side of the piston crown surface 15 through an inner pipe of the oil jet 23.
The injection nozzle 32 has a first pipe 36 having a supply port 35 communicating with the cylindrical passage 34 side (the oil supply passage 26 side) and a second pipe 38 having an injection orifice 37 located at an outlet side and injecting or spraying the engine oil. These first pipe 36 and second pipe 38 are connected or joined together with their axes forming a predetermined angle (in this embodiment, a substantially 90 degrees).
The first pipe 36 is shaped into a linear shape having the same radial direction cross section (a passage cross section) including the supply port 35. The second pipe 38 is shaped into a linear shape having the same radial direction cross section including the injection orifice 37, and is formed so as to be sufficiently greater than the supply port 35 and a minimum radial direction cross section of the first pipe 36. More specifically, the second pipe 38 is formed such that a minimum radial direction cross section of the second pipe 38 is four times the minimum radial direction cross section of the first pipe 36 or more.
Further, as shown in
In contrast to this, as shown in
Next, an oil jet 23B of a second embodiment of the present invention will be explained with reference to
At this time, in the second embodiment, since the axis 36A of the first pipe 36 is offset from the axis 38A of the second pipe 38 to a lower side in
In this manner, in the second embodiment, since the injection of the engine oil is performed while maintaining the turning flow Y1 in the second pipe 38, as shown in
If the offset amount e is too large, the turning flow Y1 is too strong, then linearity of spray is degraded. It is therefore preferable to set the offset amount e to within a certain limited range. To check the linearity with respect to the offset amount, as shown in
Further, a supply pipe 45 to which the injection pipe 43 is connected is formed integrally with the oil jet body 30. This supply pipe 45 has a radial direction cross section that is set to be smaller than that of an inside of the injection pipe 43.
Therefore, in a case of a configuration of the fifth embodiment, a section of the injection pipe 43 at an injection orifice 37 side with respect to the curved portion 44 forms the second pipe 38. A section of the injection pipe 43 at a side opposite to the injection orifice 37 with respect to the curved portion 44 and the supply pipe 45 provided with the supply port 35 form the first pipe 36. Then, the radial direction cross section of the second pipe 38 (the injection pipe 43) including the injection orifice 37 is set to be greater than the radial direction cross section of an inside of the supply pipe 45 which is a minimum cross section of the first pipe 36.
As described above, also in the fifth embodiment, in the same way as the first embodiment, since the passage cross section of the second pipe 38 is set to be greater than that of the first pipe 36, it is possible to increase the cooling efficiency.
As a modified example of the fifth embodiment, as shown in
Next, distinctive structure and effect of the above embodiments will be described.
[1] As shown in
Therefore, the injected engine oil is mixed with air, and the flow of the engine oil becomes spray of particulate droplets. As a result, the injection range (the injection area) of the engine oil is broadened, and the engine oil widely contacts or adheres to the back surface side of the piston crown surface 15. A piston temperature reduction effect is therefore greatly increased. By the reduction in piston temperature, degradation of strength of the piston itself at a high temperature can be suppressed, thereby improving reliability. Further, since a temperature of the piston crown surface 15 is decreased, an engine knocking is also suppressed.
[2] Further, the injection nozzle 32 is formed such that the minimum radial direction cross section of the second pipe 38 is greater than the minimum radial direction cross section of the first pipe 36. Therefore, as shown in
[3] Moreover, the oil jet 23 for the internal combustion engine is configured such that when the pressure of the engine oil supplied to the oil supply passage 26 of the internal combustion engine is equal to or greater than a predetermined value, the engine oil spontaneously jets.
Since the engine oil spontaneously jets by the oil pressure in this manner, a structure of the oil jet can be simplified without requiring an electromagnetic valve. In a case of such a hydraulically actuated oil jet, the engine oil is injected also at an engine start at which the oil pressure is high. Here, as shown in the reference example of
[4] As shown in
[5] Likewise, the first pipe 36 is also formed linearly. Therefore, inertia force in the axial direction of the engine oil flowing in the first pipe 36 is strengthen, and this promotes generation of the particulate droplet when the engine oil collides with the inner wall surface of the second pipe 38. In addition, the first pipe 36 can be readily formed, for instance, by drilling.
[6] Preferably, the first pipe 36 and the second pipe 38 are connected or joined together with their axes forming 30 degrees or more. This structure promotes generation of the particulate droplet when the engine oil having flown in the first pipe 36 collides with the inner wall surface of the second pipe 38.
[7] As shown in
[8] Furthermore, in the second embodiment shown in
[9] If the offset amount e of the axis 36A of the first pipe 36 from the axis 38A of the second pipe 38 is too large, the turning flow of the injected engine oil is too strong, then linearity of spray becomes weak. As a consequence, there is a risk that the flow of the injected engine oil cannot reach the back surface side of the piston crown surface 15. Therefore, as shown in
As the oil jet for the internal combustion engine based on the embodiments explained above, for instance, the followings are raised.
As one aspect of the present invention, an oil jet for an internal combustion engine, which is provided inside the internal combustion engine and injects engine oil toward a back surface side of a piston, the oil jet comprises: an injection nozzle that injects the engine oil supplied from an oil supply passage of the internal combustion engine toward the piston, and the injection nozzle has a first pipe communicating with an oil supply passage side and a second pipe having an injection orifice that injects the engine oil, and the first and second pipes are joined together with axes of the first and second pipes forming a predetermined angle, and the injection orifice is formed such that a cross section of the injection orifice is greater than a minimum radial direction cross section of the first pipe.
As a preferable aspect of the present invention, the second pipe is formed such that a minimum radial direction cross section of the second pipe is greater than the minimum radial direction cross section of the first pipe.
As another preferable aspect of the present invention, the oil jet for the internal combustion engine is configured such that when a pressure of the engine oil supplied to the oil supply passage of the internal combustion engine is equal to or greater than a predetermined value, the engine oil is injected.
As a preferable aspect of the present invention, the second pipe is formed linearly.
As a preferable aspect of the present invention, the first pipe is formed linearly.
The first and second pipes are joined together with the axes of the first and second pipes forming, for instance, 30 degrees or more.
As a preferable aspect of the present invention, the second pipe is formed such that the minimum radial direction cross section of the second pipe is four times the minimum radial direction cross section of the first pipe or more.
As another preferable aspect of the present invention, an axis of the first pipe is offset from an axis of the second pipe.
As another preferable aspect of the present invention, an offset amount of the axis of the first pipe from the axis of the second pipe is set to be equal to or less than 15% with respect to a diameter of the second pipe.
As another preferable aspect of the present invention, the second pipe is molded into a long hole shape by a plurality of drilling processes.
As a further preferable aspect of the present invention, the second pipe is formed into a cone shape whose radial direction cross section is gradually increased toward the injection orifice.
From another viewpoint, a piston cooling device for an internal combustion engine, which is provided inside the internal combustion engine and injects engine oil toward a back surface side of a piston, the piston cooling device comprises: a supply pipe supplied with the engine oil from the internal combustion engine; and an injection pipe communicating with the supply pipe and having an injection orifice injecting the engine oil toward the piston, and the injection orifice is formed such that a cross section of the injection orifice is greater than a minimum radial direction cross section of the supply pipe.
As a preferable aspect of the present invention, the supply pipe has a part whose radial direction cross section is squeezed so as to have an orifice shape.
As another preferable aspect of the present invention, the supply pipe is formed such that a radial direction cross section of a connecting portion with the injection pipe is small.
From another viewpoint, an oil jet for an internal combustion engine, which is provided inside the internal combustion engine and injects oil toward a back surface side of a piston, the oil jet comprises: an injection nozzle that injects the oil supplied from an oil supply passage of the internal combustion engine toward the piston, and the injection nozzle has a first pipe communicating with the oil supply passage and a second pipe having an injection orifice that injects the oil, and the first and second pipes are joined together with axes of the first and second pipes forming a predetermined angle, and
an axis of the second pipe is offset from an axis of the first pipe.
Claims
1. An oil jet for an internal combustion engine, which is provided inside the internal combustion engine and injects engine oil toward a back surface side of a piston, the oil jet comprising:
- an injection nozzle that injects the engine oil supplied from an oil supply passage of the internal combustion engine toward the piston, and
- the injection nozzle having a first pipe communicating with an oil supply passage side and a second pipe having an injection orifice that injects the engine oil, and the first and second pipes being joined together with axes of the first and second pipes forming a predetermined angle, and
- the injection orifice being formed such that across section of the injection orifice is greater than a minimum radial direction cross section of the first pipe.
2. The oil jet for the internal combustion engine as claimed in claim 1, wherein:
- the second pipe is formed such that a minimum radial direction cross section of the second pipe is greater than the minimum radial direction cross section of the first pipe.
3. The oil jet for the internal combustion engine as claimed in claim 2, wherein:
- the oil jet for the internal combustion engine is configured such that when a pressure of the engine oil supplied to the oil supply passage of the internal combustion engine is equal to or greater than a predetermined value, the engine oil is injected.
4. The oil jet for the internal combustion engine as claimed in claim 2, wherein:
- the second pipe is formed linearly.
5. The oil jet for the internal combustion engine as claimed in claim 4, wherein:
- the first pipe is formed linearly.
6. The oil jet for the internal combustion engine as claimed in claim 5, wherein:
- the first and second pipes are joined together with the axes of the first and second pipes forming 30 degrees or more.
7. The oil jet for the internal combustion engine as claimed in claim 2, wherein:
- the second pipe is formed such that the minimum radial direction cross section of the second pipe is four times the minimum radial direction cross section of the first pipe or more.
8. The oil jet for the internal combustion engine as claimed in claim 5, wherein:
- an axis of the first pipe is offset from an axis of the second pipe.
9. The oil jet for the internal combustion engine as claimed in claim 8, wherein:
- an offset amount of the axis of the first pipe from the axis of the second pipe is set to be equal to or less than 15% with respect to a diameter of the second pipe.
10. The oil jet for the internal combustion engine as claimed in claim 2, wherein:
- the second pipe is molded into a long hole shape by a plurality of drilling processes.
11. The oil jet for the internal combustion engine as claimed in claim 2, wherein:
- the second pipe is formed into a cone shape whose radial direction cross section is gradually increased toward the injection orifice.
12. A piston cooling device for an internal combustion engine, which is provided inside the internal combustion engine and injects engine oil toward a back surface side of a piston, the piston cooling device comprising:
- a supply pipe supplied with the engine oil from the internal combustion engine; and
- an injection pipe communicating with the supply pipe and having an injection orifice injecting the engine oil toward the piston, and
- the injection orifice being formed such that across section of the injection orifice is greater than a minimum radial direction cross section of the supply pipe.
13. The piston cooling device for the internal combustion engine as claimed in claim 12, wherein:
- the supply pipe has a part whose radial direction cross section is squeezed so as to have an orifice shape.
14. The piston cooling device for the internal combustion engine as claimed in claim 13, wherein:
- the supply pipe is formed such that a radial direction cross section of a connecting portion with the injection pipe is small.
15. An oil jet for an internal combustion engine, which is provided inside the internal combustion engine and injects oil toward a back surface side of a piston, the oil jet comprising:
- an injection nozzle that injects the oil supplied from an oil supply passage of the internal combustion engine toward the piston, and
- the injection nozzle having a first pipe communicating with the oil supply passage and a second pipe having an injection orifice that injects the oil, and the first and second pipes being joined together with axes of the first and second pipes forming a predetermined angle, and an axis of the second pipe being offset from an axis of the first pipe.
Type: Application
Filed: Mar 29, 2016
Publication Date: Oct 25, 2018
Applicant: HITACHI AUTOMOTIVE SYSTEMS, LTD. (Hitachinaka-shi, Ibaraki)
Inventor: Keitarou SHISHIDO (Atsugi-shi, Kanagawa)
Application Number: 15/569,910