JP2006283603A - Piston cooling device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To jet cooling oil on a piston only in a low and middle rotation speed zone by a simple structure. <P>SOLUTION: Cooling oil reaches a nozzle 2 from an oil gallery G formed in a cylinder block S via a valve device 1. The valve device 1 is provided with a main body 3, a valve element 4 of ball type or the like movably arranged in the main body 1, and a spring 9 pressing the valve element 4 toward a flow in side valve seat 7. A discharge side valve seat 8 on which the valve element 4 abuts to close the passage when oil pressure rises up to a predetermined value is provided in the main body 3. Consequently, jet of oil is stopped to prevent over cooling of a piston P when an engine reaches high sped zone. Since the valve device has a simple structure, operation is sure and durability and reliability are high. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a piston cooling device for an internal combustion engine (hereinafter referred to as “engine”).

  In an automobile engine, in order to prevent the piston from being heated and causing adverse effects such as knocking and seizure, a nozzle N communicating with the oil gallery G is provided in the cylinder block S as shown in FIG. Is sprayed onto the piston P from the opposite side to the combustion chamber B to cool the piston P. As the cooling oil, lubricating oil stored in an oil pan is used together, and a part of the oil pumped from the oil pump is used for cooling the piston P.

  The simplest example of a structure in which oil is blown to the piston by starting the engine is to insert a check valve in the oil passage, but in this structure, the oil is always ejected during operation of the engine, and The amount of oil ejection increases in proportion to the engine speed.

  However, in the high-speed rotation range, the effect of suppressing knocking due to cooling of the piston is small, and there is also a problem that the output loss of the engine occurs due to an increase in driving energy of the oil pump. That is, in the engine, it is preferable to cool the piston in the low and medium speed rotation range, but there is no need for cold air in the high speed rotation range.

Therefore, in Patent Document 1 and Patent Document 2, a control valve that is remotely controlled is provided in an oil passage for spraying on the piston, and the control valve is automatically closed when the engine speed increases to a set value. It is described to operate.
Japanese Utility Model Sho 61-65233 microfilm Japanese Utility Model Sho 63-125130 microfilm

  According to Patent Documents 1 and 2, it is possible to prevent piston overcooling and engine output loss, but it is necessary to use a remote control device such as a solenoid valve, and a dedicated control circuit is required. There is a problem that the whole structure is remarkably complicated and cost increases. Further, since a control valve such as a solenoid valve has a precise structure, there is a high possibility that foreign matter mixed in the oil is clogged inside and becomes inoperable.

  The present invention has been made in view of such a current situation, and an object of the present invention is to provide a piston cooling device having a simple structure and excellent reliability and reliability of operation.

  In order to solve the above problems, the present invention relates to an internal combustion engine configured to cool a piston by spraying oil pumped from an oil pump driven by the engine to the piston from a side opposite to the combustion chamber. In the oil passage where oil flows toward the nozzle, a valve device is provided that opens and closes the passage when the valve body moves against the spring, and this valve device is installed in one direction against the spring. The passage is open until the valve body moves to a predetermined position in the movement, and when the valve body moves beyond the predetermined position, the passage is completely or partially closed. When the pressure exceeds a predetermined value, the amount of oil sprayed onto the piston is set to be reduced or reduced.

  Since the oil pump is driven by the engine, the oil pressure increases as the engine speed increases, and when the oil pressure rises to a predetermined value, the oil passage is completely or partially closed by the valve body, The spraying of oil on the piston is stopped or suppressed. As a result, piston overcooling and engine output loss can be prevented.

  Since the valve device of the present invention is automatically operated by the pressure of oil, a control circuit is unnecessary, and the valve body has a simple structure that moves in one direction against the spring. For this reason, the cost of a cooling device becomes remarkably low compared with patent document 1. FIG. In addition, since the structure is simple, the operation and responsiveness are reliable and the reliability is high.

  Next, an embodiment of the present invention will be described with reference to the drawings.

(1). First embodiment (FIGS. 1 to 3)
1 and 2 show the structure of the first embodiment. The oil blowing mechanism in the present embodiment is basically the same as the conventional one. The valve device 1 communicating with the oil gallery G formed in the cylinder block S is attached to the inner bottom portion of the cylinder block S. Oil is sprayed onto the piston P from the opposite side of the combustion chamber by the nozzle 2 that extends.

  The valve device 1 according to the present embodiment includes a substantially cylindrical main body 3 fixed to the cylinder block S by screwing, a ball-type valve body 4 disposed inside the main body 3 so as to be movable in the axial direction thereof, A cover plate 5 fitted into the opening of the main body 3 and a cap 6 screwed into the main body 3 so as to prevent the cover plate 5 from falling off are provided. An inflow side valve seat 7 to which the ball type valve element 3 hits is formed in an upstream portion of the inside of the main body 3, and a cylindrical discharge side extending toward the ball type valve element 4 is formed on the cover plate 5. The valve seat 8 is fixed (may be integrally molded).

  Further, a spring (coil spring) 9 that pushes the ball type valve element 4 toward the inflow side valve seat 7 is fitted to the discharge side valve seat 8. In the present embodiment, the discharge-side valve seat 8 and the nozzle 2 are constituted by a single pipe and both extend in series, but they may be composed of different members. The lid plate 5 and the cap 6 may be integrated, or the lid plate 5 may be eliminated and the discharge side valve seat 8 and the nozzle 2 may be provided on the cap 6. The cap 6 is not limited to the screw-in type, and may be a forced fitting type.

  In the above configuration, FIGS. 1 and 2 (A) show the engine stop state. In this state, the ball type valve element 4 contacts the inflow side valve seat 7 of the main body 3 and the passage is closed. When oil flows into the valve device 1, the ball type valve element 4 moves toward the discharge side valve seat 8 against the spring 9 by the pressure of the oil, as shown in FIG.

  Until the pressure of the oil reaches a certain level, gaps are opened between the ball type valve element 4 and the inflow side valve seat 7 and between the ball type valve element 4 and the discharge side valve seat 8. Therefore, the passage is open and oil is ejected from the nozzle 2 toward the piston P. When the engine speed further increases and the oil pressure reaches a predetermined value, the ball-type valve body 4 abuts against the end face of the discharge-side valve seat 8 to close the hole, so that the oil passage is closed and the piston P The oil squirting into is stopped.

  The graph of FIG. 3 shows the relationship between the amount of oil jetted per unit time and the engine speed. As shown in this graph, the engine enters the high speed range and the oil pressure reaches a predetermined level. In this case, by setting the strength of the spring 9 so that the discharge side valve seat 8 is closed by the ball-type valve body 4, it is possible to automatically control so that oil is ejected only in the low and middle rotation regions.

  Since the valve device 1 has a simple structure in which the ball-type valve body 4 is elastically supported by the spring 9, there is no malfunction such as malfunction or clogging, and high reliability can be ensured with a low cost product.

  In this embodiment, when the ball-type valve body 4 approaches the discharge side valve seat 8, the gap between the two gradually decreases, so that the amount of oil ejection does not suddenly become zero at a certain pressure boundary. It decreases gradually with increasing pressure and eventually becomes zero.

(2). Second Embodiment (FIG. 4) / Others FIG. 4 shows a second embodiment. This embodiment is basically the same as the first embodiment. The difference is that a needle type valve element 10 is used instead of the ball type valve element 4 and the inflow side valve seat 7 is flat. It is a point that is formed.

  In this embodiment, the degree to which the needle type valve body 10 blocks the discharge side valve seat 8 is more gradual than in the case of the ball type valve body 4, so that the oil has a higher pressure as shown by the dashed line in FIG. As a result, the ejection amount decreases more gently than in the case of the first embodiment. In this embodiment, only the portion that fits into the discharge side valve seat 8 is formed in a needle shape, but the portion that contacts the inflow side valve seat 7 may also be formed in a needle shape.

  Specific examples of the present invention are not limited to the above-described embodiment, and various other modes can be adopted. For example, by arranging two coil springs having different lengths and outer shapes concentrically and setting the resistance to the valve body to be the sum of the two springs when the oil pressure becomes a certain strength, It is also possible to make it easier for oil to be ejected in the low-speed rotation range. Moreover, the shape of a valve body and a main body can be designed variously as needed.

It is the schematic of 1st Embodiment. It is a figure which shows the effect | action of 1st Embodiment. It is a graph which shows the relationship between the ejection amount of oil, and the rotation speed of an engine. It is a figure which shows 2nd Embodiment. It is a figure which shows a prior art.

Explanation of symbols

S cylinder block P piston G oil gallery 1 valve device 2 nozzle 3 body 4 ball type valve element 7 inflow side valve seat 8 discharge side valve seat 9 spring 10 needle type valve seat

Claims (1)

In the internal combustion engine designed to cool the piston by spraying oil pumped from the oil pump driven by the engine onto the piston from the side opposite to the combustion chamber,
In the oil passage where oil flows toward the nozzle, a valve device is provided that opens and closes the passage when the valve body moves against the spring, and this valve device is installed in one direction against the spring. The passage is open until the valve body moves to a predetermined position in the movement, and when the valve body moves beyond the predetermined position, the passage is completely or partially closed. It is set so that when the pressure exceeds a predetermined value, the amount of oil sprayed onto the piston disappears or decreases,
Piston cooling device for internal combustion engine.

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