JPH05280382A - Compression ratio control device for internal combustion engine - Google Patents

Abstract

PURPOSE:To increase a contact surface of a crank pin with an eccentric sleeve for improving the durability of a bearing, and restrict leak of high pressure oil to the low pressure side by forming a pair of communication grooves formed in an inner circumferential surfaces of the eccentric sleeve along half circles respectively. CONSTITUTION:A compression ratio control device for an internal combustion engine has an eccentric sleeve 16 freely rotatably engaged between a crank pin 12 and a larger end part of a connection rod 13. In the eccentric sleeve 16, a high pressure oil passage 31 and a low pressure oil passage 30 for changing the relative rotation position of the eccentric sleeve to the connection rod 13 are bored. In this case, a high pressure communication groove 29 communicating with the high pressure oil passage 31 is formed along almost half circle of an inner circumferential surface of the eccentric sleeve 16. At 180deg. from the high pressure communication groove 29, a low pressure communication groove 27 communicating with the low pressure oil passage 30 is formed along almost half circle in the inner circumferential surface of the eccentric sleeve 16. A contact surface between the crank pin 12 and the eccentric sleeve 16 can thus be increased to improve the durability of a bearing, and leak of high pressure oil can be restricted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compression ratio control device for an internal combustion engine (hereinafter abbreviated as "engine") in which the compression ratio is switched via pressure oil, and particularly to mechanical durability and reliability of control. It is the one that improved the sex.

[0002]

2. Description of the Related Art In general, an engine with a high compression ratio can improve fuel efficiency and the like due to an increase in thermal efficiency, as compared with a engine with a low compression ratio, but on the other hand There is a drawback that knocking is likely to occur in the rotating region and the high load region. Therefore, the one that can change the compression ratio during the operation of the engine is disclosed in, for example, Japanese Utility Model Laid-Open No. 3-92539 and Japanese Utility Model Laid-Open No. 3-1270.
No. 52, etc., the compression ratio of the engine is lowered so that knocking does not occur in the high engine speed region and high load region of the engine, while the compression ratio of the engine is increased in other operating regions where knocking is difficult to occur. , The fuel efficiency is improved with the increase of thermal efficiency.

FIG. 9 showing a cross-sectional structure in a state of low compression ratio in an example of such a conventional compression ratio control device, X- thereof.
As shown in FIG. 11 in which the stopper pin portion in FIG. 10 and FIG. 9 showing the cross-sectional shape as viewed in the direction of the arrow X is enlarged and extracted, the large ends of the crank pin 102 and the connecting rod 103 formed on the crank shaft 101 of the engine (not shown). An eccentric sleeve 104 whose outer circumferential surface is eccentric with respect to the crankpin 102 is rotatably provided between and.

During operation of the engine, it is necessary to restrain the free rotation of the eccentric sleeve 104 and to fix the eccentric sleeve 104 at a predetermined rotational position.
A stopper pin 105 that can be engaged with two locking recesses 104a, 104b formed separately from each other is provided so as to be capable of reciprocating in a direction parallel to the axis of the crankshaft 101 (left-right direction in FIG. 9). There is.

A piston 105a having a flange shape in the middle portion
Is integrally formed with the crankshaft 1
It is slidably fitted in a through hole formed in the large end of the connecting rod 103 in parallel with the axis of 01. The piston 105a of the stopper pin 105 divides the through hole into two oil chambers 106, 107, and oil passages 108, 109 facing the outer peripheral surface of the eccentric sleeve 104 communicate with the oil chambers 106, 107, respectively. Further, the connecting rod 103 in which these oil passages 108 and 109 are bored
A spring bearing cap 110 having a through hole corresponding to the outer diameter of the stopper pin 105 is fitted to the oil chamber 106 side of the through hole of the, and fixed to the large end of the connecting rod 103 via a bolt or the like not shown. Has been done. A compression coil spring 111 that biases the piston 105a toward the oil chamber 107 is interposed between the spring receiving cap 110 and the piston 105a.

A pair of flanges are formed at both ends of the eccentric sleeve 104 so as to sandwich the large end of the connecting rod 103. In the illustrated example, the large end of the connecting rod 103 has a large eccentric position. Notch-shaped locking recess formed on one of the flanges
104a is formed, and the engagement recess 104b having a notch shape is formed in the other flange portion such that the large end of the connecting rod 103 takes a small eccentric position.

That is, the stopper pin 105 moves to the left from the state shown in FIG.
By engaging with a, the large end of the connecting rod 103 and the eccentric sleeve 104 are fixed at the large eccentric position. On the other hand, the stopper pin 105 moves to the right side and the stopper pin 1
By engaging 05 with the locking recess 104b, the large end of the connecting rod 103 and the eccentric sleeve 104 are fixed at the small eccentric position.

The oil chamber 1 is formed at the large end of the connecting rod 103.
The low pressure oil passage 114 and the high pressure oil passage 115 formed in the eccentric sleeve 104, the crank pin 102, the crank arm 112, and the crank journal 113 of the crankshaft 101 are connected to the oil passages 108 and 109 respectively communicating with the crank journals.
Pressure oil is supplied to the oil chambers 106 and 107 from the 113 side.

Since the eccentric sleeve 104 rotates relative to the large ends of the crank pin 102 and the connecting rod 103, the low pressure oil passage 114 and the high pressure oil passage formed in the crank pin 102 are formed on the inner peripheral surface of the eccentric sleeve 104. A pair of annular grooves 116, 117 that can always communicate with the oil passage 115 are formed in a close state over the entire circumference, and similarly the connecting rod 1 with which the outer peripheral surface of the eccentric sleeve 104 slides.
Also on the inner peripheral surface of the large end of 03, a pair of annular grooves 118, 119 which can be always communicated with the low pressure oil passage 114 and the high pressure oil passage 115 formed in the eccentric sleeve 104 are in close proximity to each other over the entire circumference. Has been formed.

Therefore, when high-pressure oil from an oil pump (not shown) is supplied to the oil chamber 107 through the oil passage 109, the oil chamber 106
Since low-pressure oil is supplied from an oil pump (not shown) into the inside through an oil passage 108, the piston 105a of the stopper pin 105 moves to the right as shown against the spring force of the compression coil spring 111. .. As a result, the stopper pin 105 and the locking recess 104b are engaged with each other, and the large end of the connecting rod 103 is held at the small eccentric position, so that the engine is in a low compression ratio state.

On the contrary, when the low-pressure oil from the oil pump (not shown) is supplied to the oil chamber 107 through the oil passage 109, the low-pressure oil from the oil pump (not shown) enters the oil chamber 106 through the oil passage 108. 11 is supplied at the same time, the piston 105a of the stopper pin 105 is driven by the spring force of the compression coil spring 111 as shown in FIG.
Move to the left from the state shown in. As a result, the stopper pin 105 and the locking recess 104a are engaged with each other, and the large end of the connecting rod 103 is held in the large eccentric position, so that the engine is in the high compression ratio state.

[0012]

In the conventional compression ratio control device for an engine shown in FIGS. 9 to 11, two annular grooves 116 and 117 are formed over the entire circumference of the inner peripheral surface of the eccentric sleeve 104. Therefore, the contact area between the crank pin 102 and the eccentric sleeve 104 is reduced, and the eccentric sleeve as the bearing metal is
It is difficult to keep the durability of 104 high.

Moreover, since these two annular grooves 116, 117 are in close proximity to each other, pressure oil easily leaks from the high pressure side annular groove 117 to the low pressure side annular groove 116, and the high pressure side annular groove 117. When pressure oil is supplied to the stopper pin 105, the switching operation of the stopper pin 105 may be delayed, and it is difficult to perform accurate compression ratio switching control.

[0014]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a compression ratio control device for an engine capable of performing accurate compression ratio switching control without impairing the durability of the eccentric sleeve as the bearing metal. ..

[0015]

In a compression ratio control system for an engine according to a first aspect of the present invention, an eccentric sleeve is rotatably fitted between a crank pin and a large end portion of the connecting rod, and is connected to the connecting rod. In a compression ratio control device for an internal combustion engine in which a high-pressure oil passage and a low-pressure oil passage for switching the relative rotational position of the eccentric sleeve are formed in the eccentric sleeve, the compression ratio control device covers approximately half of the inner peripheral surface of the eccentric sleeve. And a high-pressure communication groove that is formed to communicate with the high-pressure oil passage, and is formed over approximately half of the inner peripheral surface of the eccentric sleeve at a distance of approximately 180 degrees from the high-pressure communication groove and communicates with the low-pressure oil passage. It is equipped with a low-pressure communication groove.

According to a second aspect of the present invention, there is provided an engine compression ratio control device comprising: an eccentric sleeve rotatably fitted between a crankpin and a large end portion of a connecting rod; A stopper pin that engages with one of a pair of engaging portions formed separately from the sleeve to switch the relative rotational position of the connecting rod and the eccentric sleeve, and is drilled from the crank pin to the crank journal. And a first oil passage to which pressure oil is supplied from the crank journal side, and the crank pin is bored so as to communicate with the first oil passage in an intersecting state with the first oil passage, and both ends are the outer peripheral surface of the crank pin. A second oil passage opening to the second oil passage, a communication groove formed over almost the half circumference of the inner peripheral surface of the eccentric sleeve so as to always communicate with the second oil passage, and to connect to this communication groove. To the eccentric A plurality of third oil passages radially formed in the groove, and an arc shape along the circumferential direction of the inner peripheral surface of the large end of the connecting rod so as to always communicate with these third oil passages. For supplying the hydraulic oil which is formed on the connecting groove and the large diameter end portion of the connecting rod which is connected to the connecting groove and which urges the stopper pin toward at least one of the engaging portions. It has a fourth oil passage.

[0017]

In the first aspect of the present invention, the high-pressure communication groove and the low-pressure communication groove are formed only on approximately half of the inner peripheral surface of the eccentric sleeve, and the bearing durability is increased by increasing the contact area between the crankpin and the eccentric sleeve. Is improved. Further, since the high-pressure communication groove and the low-pressure communication groove are formed so as to be separated by about 180 degrees, the high-pressure oil supplied to the high-pressure communication groove is unlikely to leak to the low-pressure communication groove side, and the control response is improved. The compression ratio is switched quickly.

In the second aspect of the present invention, when pressure oil is provided from the crank pin to the crank journal and pressure oil is supplied from the crank journal side to the crank pin from the first oil passage, the pressure oil is discharged. From the both sides of the second oil passage that communicates with the first oil passage in an intersecting state, the outer peripheral surface of the crank pin,
A communication groove formed over almost half of the inner peripheral surface of the eccentric sleeve so as to always communicate with the second oil passage, a plurality of third oil passages radially provided in the eccentric sleeve, and these third oil passages. A communicating groove formed in an arc shape along the circumferential direction of the inner peripheral surface of the large end of the connecting rod so as to always communicate with the three oil passages, and on the large end of the connecting rod so as to connect to this communicating groove. The oil is supplied in the order of the drilled fourth oil passage, whereby the stopper pin is urged toward the one engagement portion side and switched to the predetermined compression ratio side.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 showing a cross-sectional structure in a high compression ratio state in an embodiment of an engine compression ratio control apparatus according to the present invention.
As shown in FIG. 2 which is a sectional view taken along the line II-II and in which the stopper pin portion in FIG. 1 is enlarged and extracted, a crank pin 12 formed on a crank shaft 11 of an engine (not shown)
A large end portion of the connecting rod 13 is rotatably fitted in the connecting rod 13, and a piston 14 capable of reciprocating in a cylinder (not shown) of the engine is pivotally attached to the small end portion of the connecting rod 13 via a piston pin 15. Has been done. An eccentric sleeve 16 having an outer peripheral surface eccentric to the crank pin 12 is rotatably provided between the crank pin 12 and the large end of the connecting rod 13.

During operation of the engine, it is necessary to restrain the free rotation of the eccentric sleeve 16 and fix the eccentric sleeve 16 at a predetermined rotational position.
A stopper pin 17 capable of engaging with two locking recesses 16a, 16b formed separately from each other is provided so as to be reciprocally movable in a direction parallel to the axis of the crankshaft 11 (left-right direction in FIG. 1). There is. The stopper pin 17, which is integrally formed with a flange-shaped piston 17a in the middle portion, is slidably fitted to the large end of the connecting rod 13 in a direction parallel to the axis of the crankshaft 11. There is.

The piston 17a of this stopper pin 17 is
Two oil chambers 18 and 19 formed at the large end of the connecting rod 13.
The oil chambers 18 and 19 are communicated with the lubricating oil passage 20 and the switching oil passage 21 which are formed at the large end of the connecting rod 13 and face the outer peripheral surface of the eccentric sleeve 16. ing. On the oil chamber 19 side of the large end portion of the connecting rod 13, an annular spring receiving cap 22 corresponding to the outer diameter of the stopper pin 17 is fitted, and the large end of the connecting rod 13 is attached via a bolt or the like not shown. It is fixed to the section. A compression coil spring 23 for urging the piston 17a toward the oil chamber 19 is interposed between the spring receiving cap 22 and the piston 17a.

A pair of flanges are formed at both ends of the eccentric sleeve 16 so as to sandwich the large end of the connecting rod 13. In this embodiment, the large end of the connecting rod 13 takes a large eccentric position. The notch-shaped engaging recess 16a is formed in one of the flanges, and the notch-like engaging recess is formed in the other flange so that the large end of the connecting rod 13 takes a small eccentric position. 16b is formed. That is, the stopper pin 17
Moves to the right from the state shown in FIGS. 1 and 3, and the stopper pin 17 and the locking recess 16b engage with each other, so that the large end of the connecting rod 13 and the eccentric sleeve 16 at the small eccentric position. Fixed. On the other hand, the stopper pin 17 moves to the left to move the stopper pin 17 and the locking recess 16a as shown in FIGS.
By engaging with, the large end of the connecting rod 13 and the eccentric sleeve 16 are fixed at the large eccentric position.

Here, when the large end of the connecting rod 13 is in the large eccentric position, the space between the crank pin 12 and the piston pin 15 is apparently extended and a high compression ratio state is realized. Further, when the large end of the connecting rod 13 is in the small eccentric position, the gap between the crank pin 12 and the piston pin 15 is apparently contracted and a low compression ratio state is realized.

4, 5, and 6, respectively showing the IV-IV arrow sectional structure, the VV arrow sectional structure, the VI-VI arrow sectional structure, and the VII-VII arrow sectional structure in FIG. As shown in FIG. 7, on the inner peripheral surface of the large end portion of the connecting rod 13 into which the eccentric sleeve 16 is fitted, a lubricating communication groove 24 connected to the lubricating oil passage 20 is formed.
And a switching communication groove 25 connected to the switching oil passage 21.
Are carved in an arc shape so as not to overlap each other in the circumferential direction of the inner peripheral surface of the large end portion, and in this embodiment, the circumferential length of the lubricating communication groove 24 is switched. It is set shorter than the circumferential length of the communication groove 25.

Further, on the inner peripheral surface of the eccentric sleeve 16,
A communication groove 27 that can always communicate with a lubricating oil supply passage 26 having both ends open to the outer peripheral surface of the crank pin 12, and a switching oil supply passage 28 having both ends open to the outer peripheral surface of the crank pin 12.
A communication groove 29, which can communicate with each other and intersects with the communication groove 27 at a distance from each other, is formed on substantially the half circumference of the inner peripheral surface of the eccentric sleeve 16 at an interval of about 180 degrees from each other. In addition, a plurality of lubricating groove communicating passages 30 connected to one communicating groove 27 are radially formed in the eccentric sleeve 16 so that the lubricating oil passage 20 and the lubricating oil supply passage 26 can always communicate with each other. ing. Similarly, a plurality of switching groove communication passages 31 connected to the other communication groove 29 are radially connected to the eccentric sleeve 16 so that the switching oil passage 21 and the switching oil supply passage 28 can always communicate with each other. Has been formed.

In the lubricating oil supply passage 26 formed in the crank pin 12, a crank arm 32, a first crank journal (hereinafter referred to as a first journal) 3
Lubricating oil passages 36 formed respectively in third and third crank journals (hereinafter, referred to as third journal) 34, fifth crank journals (hereinafter, referred to as fifth journal) 35 are connected, When a high compression ratio is selected, pressure oil (not shown) is supplied to the oil chamber 18 from the first journal 33, the third journal 34, and the fifth journal 35 side.

The switching oil supply passage 28 formed in the crank pin 12 has a crank arm 32, a second crank journal (hereinafter, referred to as a second journal) 37, a fourth crank journal (hereinafter, referred to as a second crank journal). (This is referred to as the fourth journal) 38 is connected to the respective control oil passages 39, and when a low compression ratio is selected, pressure oil (not shown) is fed from the second journal 37 and the fourth journal 38 side to the oil chamber. 19 are supplied.

In this embodiment, lubricating oil is supplied from the first journal 33 and the fifth journal 35 located at both ends of the crankshaft 11 and the third journal 34 located in the center of the crankshaft 11 to the crankpin 12 and the eccentric sleeve. No. 3 journal 34 located in the center of the crankshaft 11 and one located at both ends of the crankshaft 11
Pressure oil is supplied to the oil chamber 19 from the second journal 37 and the fourth journal 38, which are located between the third journal 33, the fifth journal 35, and the fifth journal 35, but is limited to such an oil passage structure. Do not mean.

FIG. 8 showing a hydraulic control circuit in this embodiment.
As shown in, 1st journal 33, 3rd journal 3
The lubricating oil passages 36 formed in the fourth and fifth journals 35 respectively face the main gallery 40 outside the crankshaft 11. Also, the second journal 37 and the fourth journal 38
The control oil passages 39 respectively formed in the
It is externally connected to a hydraulic pressure switching valve 41 described later.

The pressure oil from the oil sump 42 is regulated for a preset lubrication by a lubrication oil pump 44 provided with a lubrication relief valve 43, and is supplied to the main gallery 40 via an oil filter 45. .. Then, pressure oil for lubrication is supplied from the main gallery 40 to the lubricating oil supply passage 2 through the lubricating oil passage 36.
6 to communication groove 27, lubrication groove communication passage 30, lubrication oil passage 2
In addition to being constantly supplied to the oil chamber 18 side via 0, it is distributed and supplied to each part of the engine.

The main gallery 40 and the hydraulic switching valve 41
A switching oil pump 46 for supplying high-pressure pressure oil to the hydraulic pressure switching valve 40 side is interposed between the control oil passage 3 and the control oil passage 3.
The communication state of 9 can be switched to the main gallery 40 side or the switching oil pump 46 side via the hydraulic pressure switching valve 41. Further, the hydraulic pressure switching valve 41 is provided with an electromagnetic control valve 47 for switching the energized state based on the operating state of the engine. By controlling the energized state of the electromagnetic control valve 47 by the control unit 48, The supply / discharge of pilot pressure from the main gallery 40 side is switched with respect to the hydraulic pressure switching valve 41, and the hydraulic pressure switching valve 41 is driven.

That is, when the electromagnetic control valve 47 is held in the non-energized state shown by the control unit 48 based on the operating state of the vehicle, the control oil passage 39 is connected to the main gallery 40 via the hydraulic pressure switching valve 41. The low pressure oil from the control oil passage 39 through the switching oil supply passage 28, the communication groove 29, the switching groove communication passage 31, and the switching oil passage 21.
As a result of being supplied to the side, the stopper pin 17 is engaged with the locking recess 16a of the eccentric sleeve 16 which realizes a high compression ratio state by the spring force of the compression coil spring 22. On the contrary, the control unit 48 controls the electromagnetic control valve 47 based on the driving state of the vehicle.
Is maintained in the energized state, the pilot pressure from the main gallery 40 is urged to the hydraulic pressure switching valve 41, and the high-pressure oil from the switching oil pump 46 is supplied to the oil chamber 19 via the control oil passage 32. As a result, the stopper pin 17 engages with the locking recess 16b of the eccentric sleeve 16 which realizes a low compression ratio state.

The switching of the compression ratio is carried out based on a map preset according to the operating state of the vehicle.
Further, in this embodiment, a switching relief valve 49 is attached in the middle of the control oil passage 39 so that the switching oil pump 46 can control the control oil passage 39.
The oil pressure of the pressure oil supplied to the side is adjusted against the spring force of the compression coil spring 23 so as to switch the stopper pin 17 to the right in FIG. Both the pump 44 and the switching oil pump 46 are driven by the engine.

Thus, in this embodiment, the eccentric sleeve 1
Since the communication groove 27 and the communication groove 29 formed on the inner circumference of 6 are not formed over the entire circumference, the bearing durability of the eccentric sleeve 16 is improved as compared with the conventional one. Further, between the crank pin 12 and the eccentric sleeve 16, and the eccentric sleeve 1
Although bearing metal may be interposed between 6 and the large end of the connecting rod 13, in this case, the bearing metal is integrally fixed to the connecting rod 13 and the eccentric sleeve 16. Is desirable.

[0035]

According to the compression ratio control device for an engine of the present invention, since the pair of communication grooves formed on the inner peripheral surface of the eccentric sleeve are formed on only about half the circumference, the contact area between the crankpin and the eccentric sleeve. The bearing durability can be improved by increasing In addition, the pair of communication grooves are
Since they are formed 0 degrees apart, the high pressure oil supplied to the high pressure side communication groove is unlikely to leak to the low pressure side communication groove, the control response is improved, and the compression ratio can be switched quickly. it can.

Moreover, since the pair of communication grooves and the stopper pin side are always communicated with each other, even if the communication groove is formed only on approximately half of the inner peripheral surface of the eccentric sleeve, the eccentric sleeve and the crank pin are connected. Regardless of the rotation phase, high-pressure oil can be reliably supplied to the stopper pin side, and it is possible to eliminate the problem of delay in control.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a main part in a state in which a high compression ratio is selected in an embodiment of a compression ratio control device for an engine according to the present invention.

FIG. 2 is a sectional view taken along the line II-II.

FIG. 3 is an extracted enlarged cross-sectional view of a stopper pin portion in FIG.

FIG. 4 is a sectional view taken along the line IV-IV in FIG.

5 is a cross-sectional view taken along the line VV in FIG.

6 is a sectional view taken along the line VI-VI in FIG.

FIG. 7 is a sectional view taken along the line VII-VII in FIG.

FIG. 8 is a hydraulic control circuit diagram in the present embodiment.

FIG. 9 is a cross-sectional view of a main portion showing a low compression ratio state in an example of a conventional compression ratio control device for an internal combustion engine.

FIG. 10 is a sectional view taken along line XX.

11 is a cross-sectional view of the stopper pin portion in FIG. 8 extracted in an enlarged state.

[Explanation of symbols]

11 is a crank shaft, 12 is a crank pin, 13 is a connecting rod, 14 is a piston, 15 is a piston pin, 16 is an eccentric sleeve, 16a and 16b are locking recesses, 17 is a stopper pin, 1
7a is a piston, 18 is an oil chamber, 19 is an oil chamber, 20 is a lubricating oil passage, 21 is a switching oil passage, 22 is a spring receiving cap, 23 is a compression coil spring, 24 is a lubricating communicating groove, and 25
Is a communication groove for switching, 26 is a lubricating oil supply passage, 27 is a communication groove,
28 is a switching oil supply passage, 29 is a communication groove, 30 is a lubricating groove communication passage, 31 is a switching groove communication passage, 32 is a crank arm, 33 is a 1st journal, 34 is a 3rd journal, 3
5 is a 5th journal, 36 is a lubricating oil passage, 37 is a 2nd journal, 38 is a 4th journal, 39 is a control oil passage, 40
Is a main gallery, 41 is a hydraulic switching valve, 42 is an oil sump, 43
Is a relief valve for lubrication, 44 is an oil pump for lubrication, 45 is an oil filter, 46 is an oil pump for switching, 47 is an electromagnetic control valve,
Reference numeral 48 is a control unit, and 49 is a switching relief valve.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masahiko Matsuda 5-3-8, Shiba, Minato-ku, Tokyo Mitsubishi Motors Corporation (72) Inventor Takaaki Hirano, No. 1 Uzumasacho, Ukyo-ku, Kyoto Prefecture Mitsubishi Motors Engineering Co., Ltd. Kyoto Office

Claims (2)

[Claims] 1. An eccentric sleeve is rotatably fitted between a crank pin and a large end of a connecting rod, and a high pressure oil passage and a low pressure oil passage for switching a relative rotational position of the eccentric sleeve with respect to the connecting rod. In a compression ratio control device for an internal combustion engine having a hole formed in the eccentric sleeve, a high-pressure communication groove formed over almost half of the inner peripheral surface of the eccentric sleeve and communicating with the high-pressure oil passage, and the high-pressure communication groove. About 18 with a groove
A compression ratio control device for an internal combustion engine, comprising: a low pressure communication groove which is formed over approximately half a circumference of an inner peripheral surface of the eccentric sleeve and is communicated with the low pressure oil passage at an interval of 0 degree. 2. An eccentric sleeve rotatably fitted between a crank pin and a large end portion of the connecting rod, and a pair of engaging portions incorporated in the connecting rod and spaced from the eccentric sleeve. A stopper pin that engages with any of the above to switch the relative rotational position between the connecting rod and the eccentric sleeve,
A first oil passage that is bored from the crank pin across the crank journal and to which pressure oil is supplied from the crank journal side, and the crank pin so as to communicate with the first oil passage in an intersecting state. A second oil passage that is bored and has both ends open to the outer peripheral surface of the crank pin, and is formed over almost half of the inner peripheral surface of the eccentric sleeve so as to always communicate with the second oil passage. Communication groove, a plurality of third oil passages radially formed in the eccentric sleeve so as to be connected to the communication groove, and a large diameter of the connecting rod so as to always communicate with these third oil passages. A communication groove formed in an arc shape along the circumferential direction of the inner peripheral surface of the end portion, and at least one of the stopper pins formed in the large end portion of the connecting rod so as to be connected to the communication groove. Fourth oil for supplying pressure oil for urging to the engaging part side Compression ratio control apparatus for an internal combustion engine equipped with and.