JP6066666B2 - Internal combustion engine - Google Patents

Description

  The present invention relates to an internal combustion engine provided with an oil jet device for cooling a piston.

  In a reciprocating internal combustion engine, it is widely performed to cool oil by jetting oil to the back side of a piston with an oil jet device. As an example, Patent Document 1 discloses that an oil passage through which oil is pumped from an oil pump is provided in a cylinder block, and an oil jet device (nozzle) is provided at an end of the oil passage.

JP 2003-74347 A

  Forming an oil passage for the oil jet in the cylinder block has the advantage of simplifying the structure compared to piping with a hose or pipe, but the oil jet device operates in conjunction with the reciprocating movement of the piston. Pulsation occurred in the flow, and this may cause abnormal noise or cause a malfunction of the knocking sensor.

  The present invention has been made to improve the current situation.

The present invention is directed to an internal combustion engine having a configuration in which an oil passage is connected to an engine body having a cylinder bore in which a piston is slidably fitted, and an oil jet device that ejects oil toward the back side of the piston. I have to.
In the invention of claim 1, a plate for preventing pulsation generated by intermittently ejecting oil from the oil jet device in conjunction with the reciprocation of the piston is provided in the oil passage. The plate is provided with one or more first oil passage holes and one or more second oil passage holes having an opening area different from that of the first oil passage hole. It is the composition that.

According to a second aspect of the present invention , in the first aspect, the first oil passage hole is formed in the center of the plate, and the first oil passage hole has a smaller diameter than the first oil passage hole. A number of second oil passage holes are formed in the circumferential direction.

In the case of claim 2 , the shape of the second oil passage hole can be arbitrarily set. For example, by forming the circumferential interval into a substantially equal rectangle or a horseshoe shape, the second oil passage hole is formed between adjacent second oil passage holes. It is possible to form this part in the taper shape which a space | interval spreads toward the radial direction outer side.

  Oil pulsation is caused by pressure changes caused by repeated stop and restart of the oil flow. When the flow stop and restart timing matches the natural frequency of the engine (cylinder block) or oil pump, the pulsation is caused by resonance. Amplifies and appears. In addition, pulsation is more likely to occur as the flow resistance decreases.

However, in the present invention, a plate having an oil passage hole is used as a pulsation preventing means, and the area of the oil passage is narrowed by this plate, so that the oil pressure change due to ON / OFF of the oil jet device is disturbed. Thus, pulsation can be prevented or significantly suppressed. As a result, it is possible to prevent or significantly suppress the occurrence of abnormal noise in the engine and the malfunction of the knocking sensor.

In particular, in the first aspect, the pulsation preventing means is constituted by a plate, and the first oil passage hole and the second oil passage hole have different opening areas, so that the vibration of the oil passing through the first oil passage hole ( Since the vibrations cancel each other out of phase between the pressure change) and the vibration of the oil passing through the second oil passage hole (pressure change), the occurrence of pulsation can be prevented or suppressed more accurately.

Furthermore, if the structure of Claim 2 is employ | adopted, since the 1st oil passage hole is in the center of a plate and a hole diameter is large, there exists an advantage which can prevent the clogging of a foreign material exactly. Further, in claim 2 , since the second oil passage hole is formed so as to surround the first oil passage hole, the oil passing through the oil passage has a difference in speed between the core layer and the surrounding layers. The effect of canceling vibrations with each other is further ensured. For this reason, the pulsation preventing function is more accurately exhibited.

In the case of this second aspect , it is particularly preferable to keep the arrangement interval (pitch in the circumferential direction) of the second oil passage holes constant so that turbulent flow can be prevented. Looking at the flow rate of the oil flowing through the oil passage, although a portion in contact with the inner surface of the passage flow rate is faster in the axial center portion for the flow velocity is reduced by the resistance, as described above, in Claim 2 If the portion between the adjacent second oil holes is formed in a tapered shape in which the gap is widened outward in the radial direction, the void ratio can be increased toward the center of the plate, so that the flow resistance acting on the plate is reduced. There is an advantage that the durability of the plate can be improved as much as possible.

(A) is a fragmentary sectional view of an internal combustion engine, (B) (C) is a figure showing another example of an oil jet device. (A) is the principal part enlarged view of FIG. 1, (B) is the BB view of (A). It is a figure which shows other embodiment and a reference example .

(1). First Embodiment Next, an embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 1A, the internal combustion engine has a cylinder block 3 having a cylinder bore 2 in which a piston 1 is slidably fitted, and a chain cover 4 fixed to one side surface 3a of the cylinder block 3. The cylinder block 3, the chain cover 4 and a cylinder head (not shown) constitute an engine body. Although a space where the timing chain is arranged is vacant between the chain cover 4 and the cylinder block 3, only a part of the chain cover 4 is displayed in FIG.

  An oil filter 5 is fixed to a lower portion of the side surface of the chain cover 4 and a portion that is displaced in the horizontal direction from a crankshaft (not shown). A first oil passage 6 communicating with the discharge port of the oil filter 5 is formed in the chain cover 4, and a second oil passage 7 communicating with the first oil passage 6 is formed in the cylinder block 3. 2 A jet nozzle 8 as an example of an oil jet device is mounted at the tip of the oil passage 7.

  The first oil passage 6 is formed in a crank shape with a horizontally long upper portion and a lower portion and a vertically long portion connecting them, and the second oil passage 7 is in a horizontal posture. In addition, it is also possible to form a passage by overlapping the cylinder block 3 with the vertically long portion of the first oil passage 6 as a long groove opened toward the one side surface 3 a of the cylinder block 3. FIG. 1A shows the cylinder bore 2 and the oil filter 5 on the same plane, but in reality, the cylinder bore 2 and the oil filter 5 are shifted in a direction perpendicular to the axis of the crankshaft. Therefore, the vertically long portion of the first oil passage 6 is inclined in a side view.

  The jet nozzle 8 in FIG. (A) protrudes inward from the inner surface of the cylinder block 3, but as an aspect of the oil jet device, the nozzle 9 is placed in the thick part of the cylinder block 3 as shown in FIG. As shown in FIG. 1C, the nozzle portion 8 'can be formed by narrowing the outlet portion of the second oil passage 7.

A pulsation prevention plate 9 as pulsation prevention means is disposed at the boundary between the first oil passage 6 and the second oil passage 7. As shown in FIG. 2, the pulsation prevention plate 9 of the embodiment is fitted into a recess 10 formed in the cylinder block 3 via a rubber rim 11 and is pressed and fixed by a chain cover 4 (the recess 10 is fixed). It is also possible to form the chain cover 4 and fit the pulsation prevention plate 9 into the chain cover 4).

  The rim 11 is insert-molded in the pulsation prevention plate 9, and in order to increase the fixing strength, an inward annular portion 11 a that slightly protrudes is provided in the oil passages 6 and 7, and the pulsation prevention plate 9 is wrapped by the rim 11. A large number of engagement holes 12 are formed in a jumped manner along the circumferential direction, and the rim 11 is passed through the engagement holes 12.

The pulsation prevention plate 9 is formed in a circular shape using a metal plate such as a stainless steel plate , a spring steel, or a steel plate as a material, and one first oil passage located at the center is exposed in the oil passages 6 and 7. The hole 13 and a large number of second oil passage holes 14 arranged at equal intervals in the circumferential direction located around the hole 13 are vacant.

  The first oil passage hole 13 has a circular shape (perfect circle), while the second oil passage hole 14 has a substantially trapezoidal shape in which two inner side surfaces 14a extending in the radial direction are parallel and a radially outer side is an arc. Yes. For this reason, the pinching portion 15 located between the adjacent second oil passage holes 14 in the pulsation prevention plate 9 is tapered (or oriented in the axial direction) with a gap extending in the direction from the axial center toward the outside. The taper is a narrower interval.

  Furthermore, the opening area of each second oil passage hole 14 is considerably smaller than the opening area of the first oil passage hole 13 (for example, the opening area of the first oil passage hole 13 is changed to the second oil passage hole 14). The opening area of 1.5 is set to about 2 to 2 times.) Furthermore, the arrangement pitch of the second oil passages 14 is set to be slightly larger than the groove width of the second oil passage holes 14. For this reason, the lateral width of the sandwiching portion 15 is larger than the groove width of the second oil passage holes 14. It is a much smaller dimension (a fraction). The width dimension of the inner peripheral portion 16 between the first oil passage hole 13 and the second oil passage hole 14 is set to be approximately the same as the width dimension of the sandwiching portion 15.

  Although not shown, the lubrication system is provided with control means for ejecting oil from the ejection nozzle 8 in conjunction with the movement of the piston 1. The control means may be provided in the ejection nozzle 8 or may be disposed in the middle of the lubrication passage.

(2) Summary of First Embodiment In the above configuration, since the oil passage is narrowed at the location of the pulsation prevention plate 9, oil flowing from the first oil passage 6 toward the second oil passage 7. Are subjected to flow resistance when passing through the pulsation prevention plate 9. Further, when the oil flow is stopped, a shock wave is radiated toward the side opposite to the ejection nozzle 8 and the shock wave is significantly attenuated by the pulsation prevention plate 9. For this reason, even if the oil flow is intermittently turned ON / OFF in conjunction with the movement of the piston 1, the oil pressure change is not smooth and irregular, and as a result, the occurrence of pulsation is prevented or significantly suppressed. it can. Therefore, abnormal noise caused by pulsation and malfunction of the knocking sensor can be prevented or significantly suppressed.

  Further, when the opening hole of the first oil passage hole 13 is opened larger than the second oil passage hole 14 as in the present embodiment, the first oil passage hole 13 is located at a place where the oil flow rate is the fastest. Therefore, the flow resistance can be suppressed as much as possible, and the foreign matter carried on the fast flow can pass through without any trouble (clogging of the foreign matter can be prevented).

Further, the sandwiching portion 15 between the adjacent second oil passage holes 14 in the pulsation prevention plate 9 is a tapered portion whose width decreases as it approaches the first oil passage hole 13. 9 as a whole, it has a structure that does not obstruct as much as possible the flow of oil flowing through the central part of the oil passages 6, 7, so that a large pressure is applied to the pulsation prevention plate 9 (stress is generated). As a result, the durability of the pulsation prevention plate 9 can be improved.

  Furthermore, since the oil flow velocity differs between the first oil passage hole 13 and the second oil passage hole 14, the phases of vibration (pressure wave / shock wave) caused by ON / OFF of the oil flow are shifted from each other. Thus, vibrations can be canceled and pulsation can be effectively prevented.

  If the oil temperature is low, the viscosity increases and the pressing force acting on the pulsation prevention plate 9 increases. However, the pulsation prevention plate 9 is made of a material and a thickness so that it can withstand even if the oil viscosity is low. Selected. When the pulsation prevention plate 9 is elastically deformed, it may resonate with ON / OFF of the oil flow, but this can be prevented by maintaining the pulsation prevention plate 9 with high rigidity.

When used with rim 11 made of rubber (or a resin) as in the embodiment, with an excellent sealing property, there is an advantage that the pulsation absorbing vibrations can be more accurately prevented. Further, when the pulsation preventing plate 9 is held by the cylinder block 3 and the chain cover 4 as in the embodiment, troublesome processing and fixing means are unnecessary, and therefore there is an advantage that the structure can be simplified and the cost can be suppressed.

(3). Other Embodiments FIG. 3 shows another embodiment of the pulsation prevention plate 9. Of these, in the example shown in (A), the pulsation prevention plate 9 is formed in a lattice shape, and the oil passage hole 17 includes four square holes 17a located in the center and satellite holes 17b arranged around the holes. And the opening areas of the two are different. In the example shown in (B), in the case where four second oil passage holes 14 are provided outside the first oil passage hole 13, the second oil passage holes 14 are formed into arc-shaped elongated holes that are long in the circumferential direction. Yes.

In the reference example shown in (C), the oil passage holes 17 are formed in a sector shape, and are arranged in the circumferential direction. The narrow portion 15 has a straight shape, but can also be formed in a taper shape with a width narrowing toward the center as indicated by a one-dot chain line. In the example shown in (D), when the first oil passage hole 13 and the second oil passage hole 14 are formed, the group of the second oil passage holes 14 is set to be spirally arranged. The narrow portion 15 is formed in a tapered shape whose width becomes narrower toward the first through hole 13.

The present invention can be embodied in various ways other than the above embodiment. For example, when using the pulsating blocking plate as pulsation preventive means, for example, Ru possible der be spaced oil passing hole in polka dot pattern.

  The present invention is actually applicable to an internal combustion engine. Therefore, it can be used industrially.

DESCRIPTION OF SYMBOLS 1 Piston 2 Cylinder bore 3 Cylinder block 4 Chain cover 5 Oil filter 6 1st oil passage 7 2nd oil passage 8 The jet nozzle as an example of an oil-jet apparatus 9 The pulsation prevention plate 10 as an example of a pulsation prevention means 10 Recess 11 Rim 13 first oil passage hole 14 second oil passage hole 15 sandwiching portion between adjacent second oil passage holes

Claims (2)

An engine body having a cylinder bore in which a piston is slidably fitted is provided with an oil passage connected to an oil jet device for injecting oil toward the back side of the piston,
A plate for preventing pulsation caused by intermittently ejecting oil from the oil jet device in conjunction with the reciprocating motion of the piston is disposed in the oil passage so as to block the oil passage. The plate has one or more first oil passage holes and one or more second oil passage holes having different opening areas from the first oil passage holes.
Internal combustion engine. There is one first oil passage hole in the center of the plate, and a second oil passage hole having a smaller diameter than the first oil passage hole jumps in the circumferential direction around the first oil passage hole. A lot of them,
The internal combustion engine according to claim 1.

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