JP2020122436A - Internal combustion engine - Google Patents

Abstract

To reduce friction at a change of a compression ratio immediately after warmup.SOLUTION: A housing 28 has a first space 61 in which a reduction gear 35 is accommodated, a second space 62 penetrated with a second control shaft 24, and a bulkhead 63 located between the first space 61 and the second space 62, and partitioning both the spaces. A first discharge hole 67 and a second discharge hole 68 for discharging a lubricant in the first space 61 to the second space 62 are formed at the bulkhead 63 so as to penetrate it. The first discharge hole 67 is located at a lower part lower than the second discharge hole 68, and formed so as to be increased in passage resistance more than that of the second discharge hole 68. An internal combustion engine supplies a larger quantity of the lubricant larger than that immediately after a start to the first space 61 during warmup for holding a compression ratio at a prescribed intermediate compression ratio. The internal combustion engine adjusts a height of an oil level in the first space 61 by the first discharge hole 67 immediately after the start, and adjusts the height by the second discharge hole 68 during the warmup.SELECTED DRAWING: Figure 3

Description

The present invention relates to an internal combustion engine equipped with a variable compression ratio mechanism.

BACKGROUND ART A variable compression ratio internal combustion engine capable of changing the compression ratio of the internal combustion engine by utilizing a multi-link type piston crank mechanism has been conventionally known.

For example, in Patent Document 1, a variable compression ratio mechanism that can change the compression ratio of an internal combustion engine according to the rotational position of a control shaft, an actuator that changes and holds the rotational position of the control shaft, and a parallel arrangement with the control shaft are provided. And an auxiliary shaft to which the rotation of the actuator is transmitted through the reduction gear, and a lever connecting the control shaft and the auxiliary shaft, and the lever reciprocates according to the rotation of the auxiliary shaft to move the lever. A variable compression ratio internal combustion engine in which a control shaft rotates in response to the above is disclosed.

In Patent Document 1, a variable compression ratio internal combustion engine has a housing for mounting a speed reducer and an actuator on an engine body. Then, in this housing, a reduction gear accommodating chamber in which a lubrication part of the reduction gear is arranged is formed. Lubricating oil is supplied to the speed reducer accommodating chamber through an oil passage formed in the oil passage forming body.
Then, in the large diameter part of the auxiliary shaft that forms a part of the wall surface of the reduction gear accommodating chamber, the position is higher at the low compression ratio than at the high compression ratio, and the oil level in the reduction gear accommodating chamber at the low compression ratio The oil hole is formed so that the height is higher than the oil level in the reduction gear housing chamber when the compression ratio is high.

Japanese Patent No. 5614505

However, Patent Document 1 does not adjust the amount of lubricating oil supplied to the speed reducer accommodating chamber according to the temperature state of the internal combustion engine. Therefore, in Patent Document 1, the amount of the lubricating oil supplied to the reduction gear accommodating chamber is reduced due to the increase in the viscosity of the lubricating oil at the time of extremely low temperature starting when the viscosity of the lubricating oil increases. There is a possibility that the temperature rising rate of the oil temperature of the lubricating oil in the speed reducer accommodating chamber becomes slow.

In the variable compression ratio internal combustion engine, when the temperature increase rate of the oil temperature in the speed reducer housing chamber becomes slow, the oil temperature of the lubricating oil in the speed reducer housing chamber immediately after the completion of warm-up operation becomes low, and the friction of the speed reducer deteriorates. , The responsiveness when changing the compression ratio deteriorates.

That is, in an internal combustion engine having a variable compression ratio mechanism that can change the compression ratio of the internal combustion engine according to the rotational position of the control shaft, and an actuator that changes and holds the rotational position of the control shaft via a speed reducer, There is room for further improvement in increasing the oil temperature of the lubricating oil in the speed reducer housing chamber immediately after the completion of warm-up operation to reduce the friction of the speed reducer immediately after completion of the warm-up operation.

An internal combustion engine of the present invention accommodates a variable compression ratio mechanism that changes a compression ratio according to a rotational position of a control shaft, an actuator that rotationally drives the control shaft via a speed reducer, the speed reducer and the control shaft. And a housing for

The housing has a first space that accommodates the speed reducer, a second space through which the control shaft penetrates, and a partition wall that separates the first space and the second space.

A first discharge hole and a second discharge hole for discharging the lubricating oil in the first space to the second space are formed through the partition wall.

The first discharge hole is located below the second discharge hole and has a passage resistance larger than that of the second discharge hole.

Immediately after the start of the internal combustion engine, the oil level height in the first space is adjusted by the first discharge hole, and when the engine is in a cold state in which the compression ratio is maintained at a predetermined compression ratio, more lubrication than immediately after the start is performed. Oil is supplied to the first space, and the height of the oil surface in the first space is adjusted by the second discharge hole.

In the internal combustion engine of the present invention, the amount of heat supplied to the first space during cooling is increased by increasing the amount of lubricating oil supplied to the first space during cooling. That is, the oil temperature of the lubricating oil in the first space can be rapidly raised during the cold period. Therefore, the internal combustion engine of the present invention can reduce the friction of the reduction gear when the compression ratio is changed immediately after warming up.

FIG. 3 is an explanatory view schematically showing a schematic configuration of a variable compression ratio mechanism applied to the internal combustion engine according to the present invention. Explanatory drawing which showed typically the connection mechanism of a 1st control axis and a 2nd control axis. The explanatory view showing typically the section of the actuator unit which is the important section of the internal-combustion engine concerning the present invention. It is explanatory drawing which showed typically the positional relationship of the housing side oil passage opening and the one end side opening of a 2nd control-shaft side oil passage, Comprising: (a) Low compression whose compression ratio is lower than an intermediate compression ratio. The compression ratio is in the intermediate compression ratio state, and the compression ratio is in the high compression ratio higher than the intermediate compression ratio. 3 is a timing chart showing changes in various state quantities at the time of cold start of the internal combustion engine according to the present invention.

An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is an explanatory view schematically showing a schematic configuration of a variable compression ratio mechanism 1 applied to an internal combustion engine according to the present invention.

An internal combustion engine (variable compression ratio internal combustion engine) having the variable compression ratio mechanism 1 is mounted, for example, in a vehicle such as an automobile as a drive source of the vehicle.

The variable compression ratio mechanism 1 is roughly composed of a piston 2, an upper link 4 as a first link, a lower link 7 as a second link, and a control link 9 as a third link. The variable compression ratio mechanism 1 is a multi-link type piston crank mechanism in which the piston 2 and the crank pin 6a of the crank shaft 6 are linked by a plurality of links.

The piston 2 is rotatably connected to one end of an upper link 4 via a piston pin 3.

The other end of the upper link 4 is rotatably connected to one end of the lower link 7 via an upper pin 5 as a first link connecting pin.

The crankshaft 6 includes a plurality of journal portions 6b and a crank pin 6a, and the journal portion 6b is rotatably supported by a main bearing (not shown) of a cylinder block (not shown). The crank pin 6a is eccentric from the journal portion 6b by a predetermined amount.

The lower link 7 is rotatably connected to the crank pin 6 a of the crank shaft 6.

One end of the control link 9 is rotatably connected to the other end side of the lower link 7 via a control pin 8 as a third link connecting pin.

The other end of the control link 9 is rotatably connected to the eccentric shaft portion 10a of the first control shaft 10 supported on the engine body side.

The first control shaft 10 made of metal is arranged parallel to the crankshaft 6 and is rotatably supported by the cylinder block, for example.

That is, the other end of the control link 9 rotatably connected to the metal eccentric shaft portion 10a is swingably supported on the engine body side.

The center axis of the eccentric shaft portion 10a is eccentric by a predetermined amount with respect to the rotation center of the first control shaft 10.

The variable compression ratio mechanism 1 changes the position of the piston 2 at the top dead center by rotating the first control shaft 10 and changing the position of the eccentric shaft portion 10a, thereby changing the mechanical compression ratio of the internal combustion engine. can do.

The first control shaft 10 regulates the degree of freedom of the lower link 7, and its rotational position is changed and held by an actuator unit 21 described later. That is, the internal combustion engine to which the present invention is applied has the actuator unit 21 that can change and hold the rotational position of the first control shaft 10.

FIG. 2 is an explanatory view schematically showing a connecting mechanism between the first control shaft 10 and the second control shaft 24 of the actuator unit 21.

Note that, in FIG. 2, for convenience of description, the configuration of a part of the second control shaft 24 and the bottom wall 64 of the housing 28, which will be described later, is omitted or simplified.

The first control shaft 10 has a metal-made bifurcated first arm portion 22, and rotates inside an internal combustion engine body including the cylinder block and an oil pan upper 23 fixed to a lower side (lower portion) thereof. Supported as possible. The first arm portion 22 extends outward in the radial direction of the first control shaft 10. That is, the first arm portion 22 projects from the first control shaft 10.

The first control shaft 10 is arranged in the internal combustion engine body in which lubricating oil (lubricating oil) is scattered.

The second control shaft 24 made of metal as a control shaft is arranged in parallel with the first control shaft 10 and extends along the oil pan upper side wall 27 in the front-rear direction of the engine. In other words, the second control shaft 24 is arranged outside the internal combustion engine body along the cylinder row direction of the internal combustion engine body.

That is, the second control shaft 24 is arranged outside the internal combustion engine body so that the axial direction of the second control shaft 24 coincides with the cylinder row direction of the internal combustion engine body. Therefore, in the present specification, the cylinder row direction and the second control shaft 24 axis direction coincide with each other.

The second control shaft 24 has a metal-made bifurcated second arm portion 26. The second arm portion 26 extends outward in the radial direction of the second control shaft 24. That is, the second arm portion 26 projects from the second control shaft 24.

The second arm portion 26 is, for example, a component press-fitted into the second control shaft 24, and is fixed to the second control shaft 24 by press-fitting.

The first arm portion 22 and the second arm portion 26 are linked (connected) by a link member 30 of the actuator unit 21. The link member 30 is an elongated metal member that is orthogonal to the first control shaft 10 and the second control shaft 24.

That is, the first control shaft 10 and the second control shaft 24 are mechanically connected by the link member 30 penetrating the oil pan upper side wall 27.

One end of the link member 30 is sandwiched at the tip of the first arm portion 22. The first arm portion 22 and the link member 30 are rotatably connected via a metal-made cylindrical first connecting pin 31. The first connecting pin 31 penetrates the tip end of the first arm portion 22 and one end of the link member 30 in a state parallel to the first control shaft 10.

The connecting portion between the first arm portion 22 and the link member 30 that is connected via the first connecting pin 31 is, for example, lubricating oil that scatters in the internal combustion engine body, or lubrication that accumulates at the bottom of the internal combustion engine body. Lubricated by oil.

The other end of the link member 30 is sandwiched at the tip of the second arm portion 26. That is, the second arm portion 26 is formed in a bifurcated shape so that the other end thereof can sandwich the other end of the link member 30. The second arm portion 26 and the link member 30 are rotatably connected via a second cylindrical connecting pin 32 made of metal. The second connecting pin 32 penetrates the tip of the second arm portion 26 and the other end of the link member 30 in a state parallel to the second control shaft 24.

The second connecting pin 32 is in a state of being relatively rotatable with respect to both the second arm portion 26 and the link member 30.

The connecting portion between the second arm portion 26 and the link member 30 that are connected via the second connecting pin 32 is lubricated by the lubricating oil supplied into the housing 28 of the actuator unit 21, for example. The lubricating oil supplied into the housing 28 is returned to the inside of the internal combustion engine main body, for example, through the link member opening (not shown) of the oil pan upper side wall 27 through which the link member 30 penetrates.

The housing 28 is fixed to the oil pan upper side wall 27. That is, the actuator unit 21 is fixed to the oil pan upper side wall 27.

When the second control shaft 24 rotates, the link member 30 reciprocates along a plane orthogonal to the first control shaft 10 due to the swing of the second arm portion 26 accompanying the rotation of the second control shaft 24. Then, the first control shaft 10 rotates as the first arm portion 22 swings as the link member 30 reciprocates. That is, the first control shaft 10 rotates as the second control shaft 24 rotates. In other words, the compression ratio of the variable compression ratio mechanism 1 is changed according to the rotational position of the second control shaft 24.

Note that the reference numeral 36 in FIG. 2 is an electric motor 36 that rotationally drives the second control shaft 24. The electric motor 36 is fixed to the housing 28.

The structure of the actuator unit 21, which is a main part of the present invention, will be described with reference to FIG. FIG. 3 is an explanatory view schematically showing a cross section of an actuator unit which is a main part of the internal combustion engine according to the present invention. In FIG. 3, the flow of the lubricating oil from the housing side oil passage 75 (described later) to the first space 61 (described later) is indicated by an arrow D1, and the first space 61 (described later) to the second space 62 (described later). The flow of lubricating oil to and from is indicated by arrow D2.

The actuator unit 21 includes a second control shaft 24, a speed reducer 35 connected to the second control shaft 24, an electric motor 36 as an actuator that rotationally drives the second control shaft 24 via the speed reducer 35, and It has a link member 30 that transmits the rotation of the second control shaft 24 to the first control shaft 10, and a housing 28 that houses a part of the link member 30, the second control shaft 24, and the speed reducer 35. ..

More specifically, the actuator unit 21 has a configuration in which the electric motor 36, the speed reducer 35, and the second control shaft 24 are arranged in series in this order from one end side (the arrow A direction side in FIG. 3) in the cylinder row direction.

The second control shaft 24 has a substantially stepped cylindrical shape, and has a flange portion 38 formed in a flange shape at one end side (the arrow A direction side in FIG. 3) in the cylinder row direction (the second control shaft 24 axial direction). Have More specifically, the second control shaft 24 serving as a control shaft is a first flange portion 38 located at one end side (the arrow A direction side in FIG. 3) in the cylinder row direction (the second control shaft 24 axial direction). The shaft portion 24a, the second shaft portion 24b as one end side shaft portion supported by the first bearing portion 66a (described later) of the housing 28, and the other end side in the cylinder row direction (second control shaft 24 axial direction) ( The third shaft portion 24c, which is located on the arrow B direction side in FIG. 3) and is supported by the second bearing portion 66b (described later) of the housing 28, serves as the other end side shaft portion.

One end side (the arrow A direction side in FIG. 3) of the second shaft portion 24b is supported by the first bearing portion 66a (described later), and the second arm portion 26 is provided on the other end side (the arrow B direction side in FIG. 3). Press-fitted and fixed.

An annular oil groove 39 that is continuous over the entire circumference is formed on the outer peripheral surface of the third shaft portion 24c that faces the second bearing portion 66b (described later).

The first shaft portion 24a has a larger diameter than the second shaft portion 24b. The second shaft portion 24b has a larger diameter than the third shaft portion 24c. That is, the second control shaft 24 has a first shaft portion 24a that is a large diameter portion, and a second shaft portion 24b and a third shaft portion 24c that are small diameter portions with respect to the first shaft portion 24a.

The first shaft portion 24a is housed in a first space 61 (described later) of the housing 28.

The other end side (the arrow B direction side in FIG. 3) of the second shaft portion 24b and the second arm portion 26 are housed in a second space 62 (described later) of the housing 28.

A second control shaft side oil passage 40 for supplying lubricating oil to a first space 61 (described later) is formed in the second control shaft 24 as a control shaft. The second control shaft side oil passage 40 has one end opening to the outer peripheral surface of the second control shaft 24 and the other end opening to the end surface of the second control shaft 24 on one end side (direction of arrow A in FIG. 3 ). There is.

The second control shaft side oil passage 40 includes a second control shaft side first oil passage 41 as an axial oil passage, a second control shaft side second oil passage 42 as one end side passage portion, and another end side passage. And a third oil passage 43 on the second control shaft side as a part.

The second control shaft-side first oil passage 41 is formed along the axial direction of the second control shaft 24, and one end thereof opens to the end face of the second control shaft 24 on one end side (arrow A direction side in FIG. 3 ). ing. That is, the one end side opening portion 41a of the second control shaft side first oil passage 41 is open to the end surface of the first shaft portion 24a on the one end side (direction of arrow A in FIG. 3). The one end side opening 41 a of the second control shaft side first oil passage 41 corresponds to the other end side opening 40 b of the second control shaft side oil passage 40.

The second control shaft-side second oil passage 42 is formed along the radial direction of the second control shaft 24, and has one end opened to the outer peripheral surface of the second shaft portion 24b facing the first bearing portion 66a (described later). , The other end is connected to the second control shaft side first oil passage 41. That is, the one end side opening 42a of the second control shaft side second oil passage 42 is open to the outer peripheral surface of the second shaft portion 24b. The one end side opening portion 42a of the second control shaft side second oil passage 42 corresponds to the one end side opening portion 40a of the second control shaft side oil passage 40.

The second control shaft-side third oil passage 43 is formed along the radial direction of the second control shaft 24, and has one end opened to the outer peripheral surface of the third shaft portion 24c facing the second bearing portion 66b (described later). , The other end is connected to the second control shaft side first oil passage 41. More specifically, the one end side opening 43a of the second control shaft side third oil passage 43 is opened to the bottom surface of the oil groove 39. The one end side opening portion 43 a of the second control shaft side third oil passage 43 corresponds to the one end side opening portion 40 a of the second control shaft side oil passage 40.

The reduction gear 35 is a so-called wave gear reduction gear, and reduces the rotation of the output shaft 36 a of the electric motor 36 and transmits the rotation to the second control shaft 24. The rotation of the output shaft 36a of the electric motor 36 may be decelerated and transmitted by using a reduction mechanism other than the wave gear reducer.

The speed reducer 35 includes an internal gear member 50, an external gear member 51 arranged concentrically inside the internal gear member 50, and an elliptical contour input side member 52 connected to an output shaft 36a of the electric motor 36. , And an output side member 53 connected to the second control shaft 24.

The internal gear member 50 is fixed to the housing 28, has an annular shape, and has a fixed gear portion 54 formed on the inner peripheral side.

The outer gear member 51 has an annular shape, and on the outer peripheral side thereof, a first gear portion 55 that meshes with the fixed gear portion 54 of the inner gear member 50 and a second gear portion 56 that meshes with the output side gear portion 58 of the output side member 53. And are formed side by side. The external gear member 51 is elastically deformed in the radial direction according to the elliptical shape of the input side member 52 inserted inside, and the internal gear member 50 and the output side member 53 are formed at two positions in the major axis direction of the elliptical shape. They are in mesh with each other.

The input side member 52 is a so-called wave generator, and its central portion is fixed to the output shaft 36 a of the electric motor 36. A bearing 57 (for example, a ball bearing) is arranged between the input side member 52 and the external gear member 51, and the external gear member 51 is rotatable relative to the input side member 52. ..

The output side member 53 has an annular shape, and the output side gear portion 58 is formed on the inner peripheral side. The output side member 53 is fixed to the flange portion 38 of the second control shaft 24 by a plurality of bolts (not shown).

Here, in the reduction gear 35, for example, the number of teeth of the first gear portion 55 of the external gear member 51 and the number of teeth of the fixed gear portion 54 of the internal gear member 50 are set to be different, and the input side member 52 is provided. Is rotated once, the outer gear member 51 and the inner gear member 50 relatively rotate by the difference in the number of teeth.

Further, the number of teeth of the second gear portion 56 of the external gear member 51 and the number of teeth of the output side gear portion 58 of the output side member 53 are set to be different, and when the input side member 52 makes one rotation, a difference in the number of teeth is obtained. The external gear member 51 and the output side member 53 rotate relative to each other.

Further, in the speed reducer 35, the ratio of the number of teeth of the fixed gear 54 to the number of teeth of the first gear 55 is smaller than the ratio of the number of teeth of the output gear 58 to the number of teeth of the second gear 56. Is set. That is, the number of teeth of the output side gear portion 58 of the output side member 53 is set to be smaller than the number of teeth of the fixed gear portion 54 of the internal gear member 50.

Therefore, the speed reducer 35 calculates the difference in rotation speed between the rotation of the external gear member 51 due to the rotation of the input side member 52 and the rotation of the output side member 53 due to the rotation of the input side member 52 with respect to the second control shaft 24. Can be output. That is, the reduction gear 35 can realize a large reduction ratio between the output shaft 36 a of the electric motor 36 and the second control shaft 24.

The electric motor 36 is fixed to an end surface of the housing 28 on one end side (direction of arrow A in FIG. 3) by a bolt or the like not shown. The output shaft 36a of the electric motor 36 projects into a first space 61 described later.

The housing 28 of the actuator unit 21 includes a first space 61, a second space 62, a partition wall 63 located between the first space 61 and the second space 62, and a partition wall 63 separating the two. And a bottom wall 64 forming two spaces. That is, in the housing 28, the first space 61, the partition wall 63, the second space 62, and the bottom wall 64 are arranged in series in this order from the one end side in the cylinder column direction (the arrow A direction side in FIG. 3). There is.

The speed reducer 35 and the flange portion 38 (first shaft portion 24a) are housed in the first space 61. Lubricating oil is supplied to the first space 61 via a second control shaft side oil passage 40 formed in the second control shaft 24.

The second space 62 accommodates the second arm portion 26, a part of the second shaft portion 24b, and the other end side of the link member 30. The second space is continuous with the link member opening (not shown) of the oil pan upper side wall 27, and the internal lubricating oil can be returned to the oil pan.

The partition wall 63 has a first bearing portion 66a as a bearing portion 66 that rotatably supports the second control shaft 24. The first bearing portion 66a corresponds to the one end side bearing portion.

A first discharge hole 67 and a second discharge hole 68 for discharging the lubricating oil in the first space 61 to the second space 62 are formed through the partition wall 63.

The first discharge hole 67 is formed near the lower end of the partition wall 63 when the vehicle is on the level ground. The first discharge hole 67 is located below the second discharge hole 68. More specifically, the first discharge hole 67 is formed in the vicinity of the lower end of the partition wall 63 in the vertical direction when the vehicle is on the flat ground. The first discharge hole 67 is formed so as to be located below the second discharge hole 68 in the vertical direction.

The first discharge hole 67 is formed so that the passage resistance is larger than that of the second discharge hole 68. In this embodiment, the diameter of the first discharge hole 67 is set smaller than the diameter of the second discharge hole 68.

A filter 69 is installed at the end of the first discharge hole 67 on the second space 62 side. The filter 69 flows into the second space 62 from the inside of the oil pan through the link member opening (not shown) of the oil pan upper side wall 27 when the vehicle equipped with the internal combustion engine is tilted, for example, on a sloped road. It is installed to prevent foreign matter (contamination) in the lubricating oil from flowing into the first space 61.

The passage resistance of the first discharge hole 67 is set so that the lubricating oil can be discharged when the oil temperature (temperature) of the lubricating oil is equal to or higher than the oil temperature after completion of warm-up.

That is, the passage resistance of the first discharge hole 67 is set so that the lubricating oil can be discharged when the oil temperature (temperature) of the lubricating oil in the first space 61 is equal to or higher than the predetermined temperature Tr.

In other words, the passage resistance of the first discharge hole 67 is such that the lubricating oil in the first space 61 can be discharged when the viscosity of the lubricating oil in the first space 61 is less than or equal to the viscosity of the lubricating oil after completion of warming up. Is set to. Further speaking, the passage resistance of the first discharge hole 67 is the first if the oil temperature of the lubricating oil in the first space 61 is the oil temperature of the lubricating oil during cooling (the oil temperature below the predetermined temperature Tr). It is set so that the lubricating oil in the space 61 is not discharged. The passage resistance of the first discharge hole 67 is such that if the oil temperature of the lubricating oil in the first space 61 is the oil temperature of the lubricating oil during cooling (the oil temperature below the predetermined temperature Tr). It may be set so that it is difficult to discharge the lubricating oil inside.

Here, the predetermined temperature Tr is, for example, the oil temperature (temperature) of the lubricating oil in the main gallery (not shown) after completion of warming up of the internal combustion engine, and at least the first temperature after completion of warming up of the internal combustion engine. It is not the oil temperature (temperature) of the lubricating oil in the space 61. The oil temperature of the lubricating oil is detected by, for example, an oil temperature sensor (not shown).

The second discharge hole 68 is formed so as to be located below the first bearing portion 66a in the vertical direction when the vehicle is on a level ground.

The passage resistance of the second discharge hole 68 is set so that the lubricating oil in the first space 61 can be discharged even if the oil temperature of the lubricating oil is the oil temperature during cooling. That is, the passage resistance of the second discharge hole 68 is set so that the lubricating oil can be discharged even when the oil temperature (temperature) of the lubricating oil in the first space 61 is lower than the predetermined temperature Tr.

In other words, the passage resistance of the second discharge hole 68 can discharge the lubricating oil in the first space 61 even if the viscosity of the lubricating oil in the first space 61 is higher than the viscosity of the lubricating oil after completion of warming up. Is set. That is, the passage resistance of the second discharge hole 68 is such that even if the oil temperature of the lubricating oil in the first space 61 is the oil temperature of the lubricating oil during cooling (the oil temperature below the predetermined temperature Tr). It is set so that the internal lubricating oil can be discharged. Further speaking, the passage resistance of the second discharge hole 68 is such that even if the outside air temperature becomes extremely low and the oil temperature of the lubricating oil in the first space 61 becomes extremely low (for example, -30° C.), It is set to discharge the lubricating oil of.

The passage resistance of the first discharge hole 67 and the second discharge hole 68 is set by appropriately setting the hole diameter, the hole length, and the like. The passage resistance of the first discharge hole 67 can be adjusted by the filter 69 described above.

The internal combustion engine can discharge the lubricating oil from the first discharge hole 67 into the first space 61 when the engine is stopped, and the amount of the lubricating oil in the first space 61 at the next low temperature start (oil level height). ) Can be adjusted (lowered). Therefore, the internal combustion engine can improve the responsiveness at the next cold start.

When the low-temperature lubricating oil is supplied to the first space 61, the internal combustion engine can adjust the oil amount (oil level) of the lubricating oil in the first space 61 by the second discharge holes 68. Therefore, the internal combustion engine can improve the responsiveness at the time of cold start.

The lubricating oil supplied to the first space 61 lubricates each part of the speed reducer 35 and is discharged to the second space 62 via the first discharge holes 67 and the second discharge holes 68 formed in the partition wall 63. It The lubricating oil discharged from the first space 61 to the second space 62 is returned to the oil pan via the link member opening (not shown) of the oil pan upper side wall 27.

The bottom wall 64 has a second bearing portion 66b as a bearing portion 66 that rotatably supports the second control shaft 24. The second bearing portion 66b corresponds to the other bearing portion.

Further, in the housing 28, a housing-side first oil passage 76 as a housing-side oil passage 75 for supplying lubricating oil to the first bearing portion 66a through the partition wall 63, and a second bearing portion 66b through the bottom wall 64. And a housing-side second oil passage 77 as a housing-side oil passage 75 for supplying lubricating oil to the.

Lubricating oil is supplied to the housing-side first oil passage 76 and the housing-side second oil passage 77 from an oil pump (not shown).

In the housing-side first oil passage 76, a housing-side first oil passage opening 79, which is an opening on one end side, opens on the inner peripheral surface of the first bearing portion 66a, and the other end side communicates with an oil pump (see FIG. Connected (not shown). The housing-side first oil passage opening 79 is an opening on one end side of the housing-side oil passage 75, and corresponds to the housing-side oil passage opening 78 that opens to the inner peripheral surface of the bearing portion 66.

The lubricating oil supplied to the first bearing portion 66a by the housing-side first oil passage 76 lubricates between the second shaft portion 24b and the first bearing portion 66a, and at the same time, the second control shaft-side second oil passage 42 is provided. And is supplied to the first space 61 via the first oil passage 41 on the second control shaft side.

The housing-side first oil passage opening 79 and the one end-side opening 42a of the second control shaft-side second oil passage 42 are formed at positions where they overlap each other in the axial direction of the second control shaft 24.

The housing-side first oil passage opening 79 and the one end-side opening portion 42a of the second control shaft-side second oil passage 42 are defined by the second control shaft 24 when the second control shaft 24 has a predetermined rotation angle. The positions along the circumferential direction of are overlapped with each other.

Therefore, the housing-side first oil passage opening 79 and the one-end opening 42a of the second control shaft-side second oil passage 42 are entirely overlapped when the second control shaft 24 is at a predetermined rotation angle.

In the housing-side second oil passage 77, a housing-side second oil passage opening 80, which is an opening on one end side, opens on the inner peripheral surface of the second bearing portion 66b, and the other end side communicates with an oil pump (see FIG. Connected (not shown). The housing-side second oil passage opening 80 is an opening on one end side of the housing-side oil passage 75, and corresponds to the housing-side oil passage opening 78 that opens to the inner peripheral surface of the bearing portion 66.

The lubricating oil supplied to the second bearing portion 66b by the housing-side second oil passage 77 lubricates the space between the third shaft portion 24c and the second bearing portion 66b, and also the second control shaft-side third oil passage 43. And is supplied to the first space 61 via the first oil passage 41 on the second control shaft side.

The housing-side second oil passage opening 80 and the one end side opening 43a of the second control shaft-side third oil passage 43 are formed at positions where they overlap each other in the axial direction of the second control shaft 24.

The housing-side second oil passage opening 80 and the one end-side opening 43a of the second control shaft-side third oil passage 43 are used for the second control shaft 24 when the second control shaft 24 has a predetermined rotation angle. The positions along the circumferential direction of are overlapped with each other.

Therefore, the housing-side second oil passage opening 80 and the one end side opening 43a of the second control shaft-side third oil passage 43 are entirely overlapped when the second control shaft 24 is at a predetermined rotation angle.

That is, in the housing-side oil passage 75, the housing-side oil passage opening 78, which is an opening on one end side, opens on the inner peripheral surface of the bearing portion 66, and the other end side is an oil passage (not shown) leading to the oil pump. It is connected. The lubricating oil supplied to the bearing portion 66 by the housing-side oil passage 75 lubricates the space between the second control shaft 24 and the bearing portion 66, and enters the first space 61 via the second control shaft-side oil passage 40. Supplied.

The housing side oil passage opening 78 and the one end side opening 40a of the second control shaft side oil passage 40 that opens to the outer peripheral surface of the second control shaft 24 are positioned so as to overlap each other in the axial direction of the second control shaft 24. Has been formed. The housing side oil passage opening 78 and the one end side opening 40a of the second control shaft side oil passage 40 are arranged in the circumferential direction of the second control shaft 24 when the second control shaft 24 has a predetermined rotation angle. The positions are set to overlap each other.

Therefore, the housing side oil passage opening 78 and the one end side opening 43a of the second control shaft side oil passage 40 are entirely overlapped when the second control shaft 24 is at a predetermined rotation angle.

In this embodiment, when the compression ratio of the internal combustion engine is a predetermined intermediate compression ratio (for example, a compression ratio of 9.5), the housing-side oil passage opening 78 and one end-side opening 40a of the second control shaft-side oil passage 40 are formed. And are set to overlap as a whole.

More specifically, referring to FIG. 4, the housing-side oil passage opening 78 of the housing-side oil passage 75 and the one end-side opening 40a of the second control shaft-side oil passage 40 correspond to the rotation angle of the second control shaft 24. Thus, the distance on the sliding surface between the bearing 66 and the second control shaft 24 changes.

FIG. 4 is an explanatory diagram schematically showing the positional relationship between the housing side oil passage opening 78 and the one end side opening 40a for each compression ratio. In FIG. 4, the flow of the lubricating oil from the housing side oil passage 75 to the second control shaft side oil passage 40 is indicated by an arrow D3.

FIG. 4A shows a state where the compression ratio is lower than the intermediate compression ratio (for example, compression ratio 8). In the internal combustion engine, when the compression ratio is lower than a predetermined intermediate compression ratio (for example, 9.5), as shown in FIG. 4A, the housing side oil passage opening 78 and the one end side opening 40a. And are set so as not to overlap each other.

FIG. 4B shows a state where the compression ratio is the intermediate compression ratio (for example, 9.5). In the internal combustion engine, when the compression ratio is a predetermined intermediate compression ratio, as shown in (b) of FIG. 4, the housing side oil passage opening 78 and the one end side opening 40a of the second control shaft side oil passage 40 are separated from each other. It is set to overlap as a whole. That is, in the internal combustion engine, when the compression ratio is the predetermined intermediate compression ratio, the housing-side oil passage opening 78 and the one end-side opening 40a of the second control shaft-side oil passage 40 form the bearing 66 and the second control shaft. It is set so as to be located at the same position on the sliding surface with 24.

FIG. 4C shows a state of a high compression ratio (for example, compression ratio 14) in which the compression ratio is higher than the intermediate compression ratio. In the internal combustion engine, when the compression ratio is higher than the intermediate compression ratio, as shown in (c) of FIG. 4, the housing side oil passage opening 78 and the one end side opening of the second control shaft side oil passage 40 are opened. The parts 40a are set so as not to overlap each other.

In this embodiment, when the second control shaft 24 rotates clockwise in FIG. 4, the compression ratio becomes relatively high, and when the second control shaft 24 rotates counterclockwise in FIG. 4, the compression ratio becomes relatively high. It is low. Therefore, the one end side opening 40a of the second control shaft side oil passage 40 shifts counterclockwise with respect to the housing side oil passage opening 78 as the compression ratio becomes lower than the intermediate compression ratio. Further, the one end side opening 40a of the second control shaft side oil passage 40 is displaced clockwise with respect to the housing side oil passage opening 78 as the compression ratio becomes higher than the intermediate compression ratio.

Therefore, the passage resistance of the lubricating oil supply passage for the first space for supplying the lubricating oil from the housing side oil passage 75 to the first space 61 via the second control shaft side oil passage 40 is equal to the rotation angle of the second control shaft 24. The smaller the distance between the housing side oil passage opening 78 and the one end side opening 40a of the second control shaft side oil passage 40 on the sliding surface between the bearing 66 and the second control shaft 24, the smaller the distance. Become.

In other words, the passage resistance of the lubricating oil supply passage for the first space becomes minimum when the housing-side oil passage opening 78 and the one end-side opening 40a of the second control shaft-side oil passage 40 overlap each other, and the housing-side oil passage. The larger the opening 78 and the one end side opening 40a of the second control shaft side oil passage 40 are on the sliding surface between the bearing 66 and the second control shaft 24, the larger the opening 78.

Therefore, the amount of lubricating oil supplied to the first space 61 increases as the passage resistance of the first space lubricating oil supply passage decreases.

That is, the passage resistance of the lubricating oil supply passage for the first space is set to be minimum when the compression ratio is the intermediate compression ratio, and becomes larger as the compression ratio deviates (shifts) from the intermediate compression ratio.

The housing side oil passage opening 78 and the one end side opening 40a of the second control shaft side oil passage 40 may be formed at positions that do not overlap each other in the axial direction of the second control shaft 24. Is. In this case, the housing side oil passage opening 78 and the one end side opening 40a of the second control shaft side oil passage 40 do not overlap each other at the intermediate compression ratio, but the bearing portion 66 and the second control shaft 24 are not overlapped with each other. The shortest distance on the sliding surface between and.

In the internal combustion engine of such an embodiment, the oil level height in the first space 61 at the time of starting can be lowered in advance by the first discharge hole 67. That is, the internal combustion engine can adjust the oil level of the lubricating oil in the first space 61 immediately after the start by the first discharge hole 67.

Then, the internal combustion engine supplies more lubricating oil to the first space 61 during warm-up (when cold) in which the compression ratio is maintained at the intermediate compression ratio than when it is started.

Further, the internal combustion engine can adjust the oil level of the lubricating oil in the first space 61 by the second discharge hole 68. As a result, the internal combustion engine can increase the oil level of the lubricating oil in the first space 61 during warm-up (when cold) in which the compression ratio is maintained at the intermediate compression ratio as compared to immediately after starting.

The internal combustion engine is supplied to the first space 61 at this time by increasing the supply amount of the lubricating oil to the first space 61 during warm-up (when cold) to maintain the compression ratio at the intermediate compression ratio. The amount of heat can be increased. That is, the oil temperature of the lubricating oil in the first space 61 can be rapidly increased during warm-up (when cold) in which the compression ratio is maintained at the intermediate compression ratio, and immediately after warm-up, that is, warm-up is completed. The deviation of the oil temperature of the lubricating oil in the first space 61 from the oil temperature of the lubricating oil (oil) in the main gallery immediately after (end) can be reduced.

Therefore, the internal combustion engine can reduce the friction of the reduction gear 35 when the compression ratio is changed immediately after warming up. As a result, the internal combustion engine has improved followability (responsiveness) of the compression ratio to the target compression ratio, and can improve fuel efficiency and power performance.

The internal combustion engine can reduce the heat capacity in the first space 61 at the time of starting by lowering the oil level height in the first space 61 in advance at the time of starting. Therefore, in the internal combustion engine, when the warmed lubricating oil is supplied to the first space 61 during warm-up (when cooling) in which the compression ratio is maintained at the intermediate compression ratio, the oil of the lubricating oil in the first space 61 is The rate of temperature rise can be increased.

In addition, the internal combustion engine increases the oil level in the first space 61 during warm-up (when cold) to maintain the compression ratio at the intermediate compression ratio, and the oil of the lubricating oil retained in the first space 61. By increasing the amount, heat transfer to the speed reducer 35 and the wall around the speed reducer 35 (the wall of the housing 28 such as the partition wall 63 forming the first space 61) can be promoted. Therefore, the internal combustion engine can rapidly increase the temperature in the first space 61 during warm-up (when cold) in which the compression ratio is maintained at the intermediate compression ratio, and immediately after warm-up, that is, warm-up is completed. The deviation of the oil temperature of the lubricating oil in the first space 61 from the oil temperature of the lubricating oil (oil) in the main gallery immediately after (end) can be reduced.

Since the internal combustion engine has a low oil level in the first space 61 at the time of starting, if the oil level in the first space 61 rises after starting, the temperature of the lubricating oil in the first space 61 rises quickly. Can be made.

Therefore, the internal combustion engine can reduce the friction of the reduction gear 35 when the compression ratio is changed immediately after warming up. Thereby, in the internal combustion engine, the followability (responsiveness) of the compression ratio to the target compression ratio is improved, and the fuel efficiency and power performance can be improved.

Immediately after warming up, the internal combustion engine can make the oil level in the first space higher than that at the time of starting because of lubrication of the speed reducer 35.

In the internal combustion engine, it is necessary to raise the compression temperature in consideration of the combustion stability when the engine is stopped and immediately after the engine is started. Further, during warm-up (when cold) after the start of the internal combustion engine, it is necessary to suppress activation of the catalyst (exhaust gas purification catalyst) by increasing exhaust gas temperature and suppress deterioration of exhaust performance. Then, in the internal combustion engine, the viscosity of the lubricating oil becomes high at a very low temperature (for example, -30° C.) and the compression ratio variable responsiveness deteriorates. It is necessary to reduce the amount of change.

Therefore, in order to raise the compression temperature (the temperature when the air-fuel mixture in the combustion chamber is compressed), the internal combustion engine when the engine is stopped takes into consideration the combustion stability immediately after the engine is started. The compression ratio for starting (for example, the compression ratio of 10.5) is set. That is, the starting compression ratio is a compression ratio set when the internal combustion engine is stopped. Then, the internal combustion engine, which is warming up after the start, is set to the intermediate compression ratio in order to raise the exhaust gas temperature.

Therefore, in the internal combustion engine, the amount of the lubricating oil that lubricates the space between the second control shaft 24 and the bearing portion 66 of the housing 28 immediately after starting is warmed up while the compression ratio is maintained at the intermediate compression ratio (when cold). In addition, the amount of the lubricating oil that lubricates between the second control shaft 24 and the bearing portion 66 of the housing 28 is larger than that of the second control shaft 24.

More specifically, in the internal combustion engine, the amount of lubricating oil that lubricates between the first bearing portion 66a and the second shaft portion 24b immediately after starting is warming up while maintaining the compression ratio at the intermediate compression ratio. The amount of lubricating oil that lubricates the space between the first bearing portion 66a and the second shaft portion 24b (when the engine is cold) is larger than the amount of lubricating oil that lubricates the space between the second bearing portion 66b and the third shaft portion 24c immediately after starting. The amount of lubricating oil used is greater than the amount of lubricating oil that lubricates between the second bearing portion 66b and the third shaft portion 24c during warm-up (when cooling) that maintains the compression ratio at the intermediate compression ratio. It is increasing.

In the internal combustion engine, since the compression ratio immediately after starting is not the intermediate compression ratio, the housing side oil passage opening 78 and the one end side opening 40a of the second control shaft side oil passage 40 do not overlap each other, and The amount of lubricating oil that lubricates between the control shaft 24 and the bearing portion 66 of the housing 28 relatively increases. That is, the internal combustion engine can secure a sufficient amount of lubricating oil that lubricates the space between the second control shaft 24 and the bearing portion 66 of the housing 28 immediately after starting.

If the internal combustion engine is left in an engine stopped state for a long period of time, it will be warmed up immediately after startup unless a sufficient amount of lubricating oil is supplied between the second control shaft 24 and the bearing portion 66 of the housing 28 immediately after startup. The oil film of the second control shaft 24 may run short during the machine (when it is cold).

Further, when the internal combustion engine does not supply a sufficient amount of lubricating oil between the second control shaft 24 and the bearing portion 66 of the housing 28 immediately after starting, the lubricating oil to the first space 61 is not supplied to the first space 61 during warm-up operation. If the supply is prioritized, a sufficient amount of lubricating oil may not be supplied between the second control shaft 24 and the bearing portion 66 of the housing 28 until the warm-up is completed.

The internal combustion engine may be disadvantageous in wear resistance when a high load is applied to the bearing portion 66 of the housing 28 due to the operating condition of the driver during warm-up (when cold) in which the compression ratio is maintained at a predetermined compression ratio. There is.

Therefore, it is desirable that the internal combustion engine refuels each sliding portion at the earliest possible timing after starting.

Then, the internal combustion engine retains the compression ratio at the intermediate compression ratio during warm-up (when cooling) after starting of the internal combustion engine, and the housing-side oil passage opening 78 and one end side of the second control shaft-side oil passage 40. Since the openings 40a are entirely overlapped with each other, the amount of lubricating oil supplied to the first space 61 is relatively increased, and the speed reducer 35 can be quickly heated.

In this embodiment, the housing-side second oil passage opening 80 and the housing-side second oil passage opening 80 are arranged at the timing when the housing-side first oil passage opening 79 and the one end-side opening 42a of the second control shaft-side second oil passage 42 overlap each other. The one end side opening 43a of the second control shaft side third oil passage 43 overlaps.

Further, the internal combustion engine has a sliding surface between the bearing portion 66 of the housing 28 and the shaft portion of the second control shaft 24 during warm-up (when cold) after the internal combustion engine that maintains the compression ratio at the intermediate compression ratio is started. Above, the housing side oil passage opening 78 and the one end side opening 40a of the second control shaft side oil passage 40 are set to overlap each other.

More specifically, in the internal combustion engine, the sliding surface between the first bearing portion 66a and the second shaft portion 24b during warm-up (when cold) after the internal combustion engine that maintains the compression ratio at the intermediate compression ratio is started. The housing-side first oil passage opening 79 and the one end-side opening 42a of the second control shaft-side second oil passage 42 overlap with each other on the sliding surface between the second bearing portion 66b and the third shaft portion 24c. The housing-side second oil passage opening 80 and the one end-side opening 43a of the second control shaft-side third oil passage 43 are set to overlap each other.

As a result, in the internal combustion engine, the passage resistance of the lubricating oil supply passage for the first space is reduced during warm-up (when cooling) after starting the internal combustion engine that maintains the compression ratio at the intermediate compression ratio. The amount of lubricating oil supplied to the space 61 increases.

The first space lubricating oil supply passage can reduce passage resistance because the housing side oil passage opening 78 and the one end side opening 40a of the second control shaft side oil passage 40 face each other.

The internal combustion engine increases the amount of lubricating oil supplied to the first space 61 during warm-up (when it is cold) after starting the internal combustion engine that maintains the compression ratio at the intermediate compression ratio, so that It is possible to increase the oil temperature of the lubricating oil, improve the efficiency of the speed reducer 35, and avoid deterioration of fuel efficiency and power performance.

The supply amount of the lubricating oil to the first space 61 is determined according to the passage resistance of the lubricating oil supply passage for the first space that supplies the lubricating oil to the first space 61, and thus the lubricating oil supply passage for the first space is provided. It can be changed (adjusted) by changing the passage resistance of.

The passage resistance of the lubricating oil supply passage for the first space can be changed according to the rotation angle of the second control shaft 24, as described above. In the internal combustion engine, if the housing side oil passage opening 78 and the one end side opening 40a of the second control shaft side oil passage 40 face each other, the bearing portion 66 of the housing 28 and the shaft portion of the second control shaft 24 are It is possible to directly supply the lubricating oil from the housing-side oil passage 75 to the second control shaft-side oil passage 40 without passing through the sliding surface of No. 2, and to increase the amount of lubricating oil supplied to the first space 61.

In the internal combustion engine, when the compression ratio is the starting compression ratio, the housing side oil passage opening 78 and the second control are formed on the sliding surface between the bearing portion 66 of the housing 28 and the shaft portion of the second control shaft 24. The shaft side oil passage 40 is set so as not to overlap the one end side opening 40a.

More specifically, in the internal combustion engine, when the compression ratio is the above-mentioned compression ratio for starting, the housing-side first oil passage opening 79 is formed on the sliding surface between the first bearing portion 66a and the second shaft portion 24b. The housing-side second oil passage opening portion 80 does not overlap the one end side opening portion 42a of the second control shaft side second oil passage 42 and is on the sliding surface of the second bearing portion 66b and the third shaft portion 24c. And the one end side opening 43a of the second control shaft side third oil passage 43 are set so as not to overlap with each other.

As a result, a sufficient amount of lubricating oil supplied to the sliding surface between the bearing portion 66 of the housing 28 and the shaft portion of the second control shaft 24 can be secured.

Further, when the vehicle equipped with the internal combustion engine of the above-described embodiment is a hybrid vehicle having an electric motor that serves as a drive source, the compression ratio set immediately after the internal combustion engine is started is set during warm-up (cooling Hour)) and the intermediate compression ratio is set to be equal to or lower than the intermediate compression ratio. That is, when the internal combustion engine of the above-described embodiment is mounted on a series hybrid vehicle or a parallel hybrid vehicle, the compression ratio for startup, which is the compression ratio set immediately after the internal combustion engine is started, is during warming up after the internal combustion engine is started. It is set so as to be equal to or lower than the above-mentioned intermediate compression ratio set to (when cold).

In the case of an internal combustion engine mounted on a hybrid vehicle, engine torque is not generated at the moment of starting the internal combustion engine, and therefore it is necessary to generate a marginal driving force by motor torque. In a hybrid vehicle, when the engine friction torque at the time of starting is large, it is necessary to increase the required torque of the motor that starts the internal combustion engine. The engine friction torque at the time of starting increases as the compression ratio increases.

Therefore, in the case of an internal combustion engine mounted on a hybrid vehicle, it is desirable to reduce the compression ratio when starting the internal combustion engine (compression ratio for starting) as much as possible.

Therefore, in the case of an internal combustion engine mounted on a hybrid vehicle, the compression ratio (starting compression ratio) set immediately after the internal combustion engine is started is set to be equal to or lower than the intermediate compression ratio. As a result, the internal combustion engine can reduce the required torque of the motor because the starting compression ratio decreases.

When the vehicle equipped with the internal combustion engine of the above-described embodiment is a vehicle that uses only the internal combustion engine as a drive source, the starting compression ratio, which is the compression ratio set immediately after the internal combustion engine is started, is It is set to be higher than the intermediate compression ratio set during warm-up (when cold) after starting.

In the case of an internal combustion engine mounted on a vehicle in which the drive source is only the internal combustion engine, a somewhat high compression ratio is required at the time of starting to ensure combustion stability. On the other hand, when the engine is cold, it is desirable to reduce the compression ratio in order to activate the catalyst due to an early temperature rise.

Therefore, in the case of an internal combustion engine mounted on a vehicle whose drive source is only the internal combustion engine, the compression ratio set immediately after the internal combustion engine is started (compression ratio for startup) is set to be higher than the intermediate compression ratio. To do. As a result, the internal combustion engine can increase the compression ratio at the time of starting to ensure combustion stability, and can reduce the compression ratio during warm-up (when cold) to achieve early temperature rise.

In the internal combustion engine, the compression ratio set (maintained) during warm-up (when cold) after starting the internal combustion engine is the intermediate compression ratio, and when the intermediate compression ratio is reached, the lubricating oil supplied to the first space 61 is The oil amount is larger than the oil amount of the lubricating oil supplied to the first space 61 when the compression ratio is higher than the intermediate compression ratio.

In other words, in the internal combustion engine, the compression ratio set (maintained) during warm-up (when cold) after starting the internal combustion engine is the intermediate compression ratio, and the oil level of the lubricating oil in the first space 61 is When the compression ratio is higher than the intermediate compression ratio, it becomes lower than when the intermediate compression ratio is high.

In the internal combustion engine, the amount of lubricating oil supplied to the first space 61 increases during warm-up (when it is cold) after the internal combustion engine is started, and the oil temperature of the lubricating oil in the first space 61 rises. It is possible to improve the efficiency of the speed reducer 35 during warm-up (when cold) after starting the engine and immediately after warm-up.

Further, in the internal combustion engine, when the compression ratio is the intermediate compression ratio, the supply amount of the lubricating oil to the first space 61 increases, so that even in the extremely low temperature (for example, −30° C.), the internal space of the first space 61 is reduced. The oil temperature of the lubricating oil can be raised rapidly.

In the internal combustion engine, since the amount of lubricating oil supplied to the first space 61 is reduced in the normal range where the compression ratio is high, the load of the oil pump in the normal range is reduced, and the fuel consumption is improved in the normal range. Can be planned.

Further, in the internal combustion engine, the load torque acting on the speed reducer 35 is maximized when the compression ratio is the intermediate compression ratio, so that the lubricating oil that is supplied to the first space 61 when the compression ratio is the intermediate compression ratio. By increasing the amount of the oil, the tooth surface wear of the speed reducer 35 can be suppressed.

In the internal combustion engine, the compression ratio set (maintained) during warm-up (when cold) is the intermediate compression ratio, and when the intermediate compression ratio is the intermediate compression ratio, the amount of lubricating oil supplied to the first space 61 is the intermediate level. When the compression ratio is lower than the compression ratio, it is larger than the amount of lubricating oil supplied to the first space 61. In other words, in the internal combustion engine, the compression ratio set (maintained) during warm-up (when cold) is the intermediate compression ratio, and the oil level of the lubricating oil in the first space 61 has the intermediate compression ratio of the intermediate compression ratio. When the compression ratio is lower than the ratio, it becomes lower than when the intermediate compression ratio.

In the internal combustion engine, since the amount of lubricating oil supplied to the first space 61 decreases when the compression ratio is a low compression ratio lower than the intermediate compression ratio, the second control shaft 24 and the housing 28 are supplied when the compression ratio is low. The amount of lubricating oil that lubricates the bearing 66 is relatively increased.

Since a high load is input to the internal combustion engine when the compression ratio is low, the internal combustion engine reduces the amount of lubricating oil supplied to the first space 61 when the compression ratio is low. It is possible to increase the amount of lubricating oil that lubricates between the 2 control shaft 24 and the bearing portion 66 of the housing 28, and improve the wear resistance of the bearing portion 66 of the housing 28.

Further, when the internal combustion engine is mounted on a hybrid vehicle, it is desirable that the internal combustion engine change the compression ratio from a low compression ratio to a high compression ratio with high thermal efficiency after starting. When the internal combustion engine changes the compression ratio, if the oil level of the lubricating oil in the first space 61 is low, the friction of the speed reducer 35 is low, and the compression ratio can be changed with high response and low power consumption. Become.

In the internal combustion engine, the oil level of the lubricating oil in the first space 61 has a predetermined prescribed oil level height H2 during warm-up (when it is cold) after the internal-combustion engine is started in which the compression ratio is maintained at the intermediate compression ratio. Is set to reach. In the present embodiment, the prescribed oil surface height H2 is the position where the second discharge hole 68 is formed.

In the present embodiment, the oil level height H1 at stop, which is the oil level of the lubricating oil in the first space 61 when the engine is stopped, is the position where the first discharge hole 67 is formed.

The internal combustion engine quickly raises the temperature of the lubricating oil in the first space 61 by raising the oil level of the lubricating oil in the first space 61 during the warm-up operation, and at the same time after the warm-up is completed. Since the required oil level height (sufficient oil level height) is secured at the start of the variable compression ratio, good lubricity of the speed reducer 35 can be reliably secured.

FIG. 5 is a timing chart showing changes in various state quantities at the time of cold start of the internal combustion engine of the above-described embodiment. More specifically, FIG. 5 is a timing chart showing changes in various state quantities at the time of starting the internal combustion engine of the above-described embodiment from an extremely low temperature state (the temperature of lubricating oil or cooling water is −30° C.).

Time t1 is the timing when cranking of the internal combustion engine is started.

Time t2 is a timing at which the lubricating oil starts to be supplied to the first space 61 due to cranking. The timing at which the lubricating oil starts to be supplied to the first space 61 is the timing at time t2, which is later than the timing for starting cranking due to the delay in the rise of the hydraulic pressure.

A characteristic line L1 shown by a solid line in FIG. 5 shows a change in the amount of lubricating oil supplied from the lubricating oil supply passage for the first space to the first space 61. A characteristic line L2 indicated by a broken line in FIG. 5 shows a change in the amount of lubricating oil discharged from the first space 61. A characteristic line L3 shown by a solid line in FIG. 5 shows a change in the oil level of the lubricating oil in the first space 61.

Time t3 is the timing when the cranking is completed, and is the timing when the target compression ratio is changed to the intermediate compression ratio.

A characteristic line L4 indicated by a broken line in FIG. 5 shows a change in the target compression ratio of the internal combustion engine. A characteristic line L5 shown by a solid line in FIG. 5 shows changes in the actual compression ratio (actual compression ratio) of the internal combustion engine.

Time t4 is the timing when the actual compression ratio reaches the intermediate compression ratio. The period from time t3 to time t4 is a period corresponding to immediately after the start of the internal combustion engine, and the lubricating oil to the first space 61 is higher than that during warming up (when cooling) in which the compression ratio is maintained at the intermediate compression ratio. Supply is low. Further, during the period from time t3 to time t4, the oil level of the lubricating oil in the first space 61 is low.

Time t5 is the timing when the oil level of the lubricating oil in the first space 61 reaches the specified oil level height H2.

Time t6 is a timing at which the cooling water temperature reaches a predetermined warm-up completion determination temperature Tc (for example, 60° C.), and is a timing at which the target compression ratio is set according to the rotational load. In this example, the target compression ratio is changed to a high compression ratio (for example, compression ratio 14) which is a compression ratio for idle operation at the timing of time t6.

A characteristic line L6 shown by a one-dot chain line in FIG. 5 shows a change in the cooling water temperature of the internal combustion engine. A characteristic line L7 indicated by a broken line in FIG. 5 shows a change in the temperature of the lubricating oil (M/G oil temperature) in the main gallery. A characteristic line L8 shown by a solid line in FIG. 5 shows a change in the lubricating oil temperature in the first space 61.

The period from time t4 to time t6 is a period during warm-up (when cold) in which the compression ratio is maintained at the intermediate compression ratio, and the supply of lubricating oil to the first space 61 is greater than immediately after the start of the internal combustion engine. The amount is increasing. In the period from time t4 to time t6, the oil level of the lubricating oil in the first space 61 is higher than immediately after the internal combustion engine is started.

Further, at the timing of time t6, the temperature of the cooling water of the internal combustion engine, the temperature of the lubricating oil in the main gallery, and the temperature of the lubricating oil in the first space 61 differ from each other due to the difference in temperature rising speed. Has occurred. At the time of starting the cold engine, as shown in FIG. 5, the rising speed of the cooling water temperature of the internal combustion engine is the fastest, and the rising speed of the lubricating oil temperature in the first space 61 is the slowest. Therefore, at the timing of time t6, the temperature increases in the order of the cooling water temperature of the internal combustion engine, the temperature of the lubricating oil in the main gallery, and the lubricating oil temperature in the first space 61.

Time t7 is the timing when the actual compression ratio reaches the target compression ratio.

Time t8 is a timing when the cooling water temperature reaches a predetermined warm-up completion temperature Th (for example, 80° C.), and is a timing when the lubricating oil in the first space 61 starts to be discharged from the first discharge hole 67.

At time t9, the M/G oil temperature (the temperature of the lubricating oil in the main gallery) indicated by the broken line in FIG. 5 coincides with the cooling water temperature at which the predetermined warm-up completion temperature Th (for example, 80° C.) is reached. is there.

Time t10 is a timing at which the lubricating oil temperature in the first space 61 shown by the solid line in FIG. 5 coincides with the cooling water temperature and the M/G oil temperature at which a predetermined warm-up completion temperature Th (for example, 80° C.) is reached. is there.

Time t11 is the timing when the ignition is turned off. The target compression ratio is changed to the starting compression ratio at the timing of time t11. In addition, the oil surface height of the lubricating oil in the first space 61 is in a state of being balanced at the above-described prescribed oil surface height H2 during the period from time t5 to time t11.

Time t12 is the timing when the actual compression ratio reaches the target compression ratio. The period from time t11 to time 12 is a period in which the actual compression ratio is changed to the starting compression ratio which is the target compression ratio changed by the ignition off.

Time t13 is a timing at which the oil level of the lubricating oil in the first space 61 reaches the oil level height H1 at the time of stop after the internal combustion engine is stopped.

Although the present invention has been described based on the specific embodiments as described above, the present invention is not limited to the above embodiments, and various modifications and alterations are included without departing from the spirit of the present invention. .. For example, in the above embodiment, the first control shaft 10 and the second control shaft 24 are connected via the link member 30, but the link member 30 and the second control shaft 24 are omitted, and the first control shaft 24 is omitted. The control shaft 10 is also applicable to an internal combustion engine having a structure in which the control shaft 10 is connected to an electric motor 36 via a speed reducer 35. In this case, the control shaft side oil passage is formed in the first control shaft 10, and the second space is penetrated by the first control shaft 10.

DESCRIPTION OF SYMBOLS 1... Variable compression ratio mechanism 21... Actuator unit 24... 2nd control shaft 24a... 1st shaft part 24b... 2nd shaft part 24c... 3rd shaft part 26... 2nd arm part 28... Housing 30... Link member 35... Speed reduction Machine 36... Electric motor 40... Second control shaft side oil passage 40a... One end side opening 40b... Other end side opening 41... Second control shaft side first oil passage 41a... One end side opening 42... Second control shaft Side second oil passage 42a... One end side opening 43... Second control shaft side third oil passage 43a... One end side opening 61... First space 62... Second space 63... Partition wall 64... Bottom wall 66... Bearing portion 66a ... 1st bearing part 66b... 2nd bearing part 67... 1st discharge hole 68... 2nd discharge hole 69... Filter 75... Housing side oil passage 76... Housing side 1st oil passage 77... Housing side 2nd oil passage 78... Housing-side oil passage opening 79... Housing-side first oil passage opening 80... Housing-side second oil passage opening

Claims (17)

A variable compression ratio mechanism that changes the compression ratio according to the rotational position of the control shaft,
An actuator that rotationally drives the control shaft via a speed reducer,
A housing that houses the speed reducer and the control shaft,
The housing has a first space for accommodating the speed reducer, a second space through which the control shaft penetrates, and a partition wall separating the first space and the second space,
The partition wall is formed with a first discharge hole and a second discharge hole for discharging the lubricating oil in the first space to the second space,
The first discharge hole is located below the second discharge hole, and is formed to have a passage resistance higher than that of the second discharge hole.
Immediately after starting the internal combustion engine, the oil level height in the first space is adjusted by the first discharge hole,
At the time of a cold machine in which the compression ratio is maintained at a predetermined compression ratio, more lubricating oil is supplied to the first space than immediately after starting, and the oil level in the first space is adjusted by the second discharge hole. Internal combustion engine characterized by. A variable compression ratio mechanism that changes the compression ratio according to the rotational position of the control shaft,
An actuator that rotationally drives the control shaft via a speed reducer,
A housing that houses the speed reducer and the control shaft,
The housing has a first space for accommodating the speed reducer, a second space through which the control shaft penetrates, and a partition wall separating the first space and the second space,
The partition wall is formed with a first discharge hole and a second discharge hole for discharging the lubricating oil in the first space to the second space,
The first discharge hole is located below the second discharge hole, and is formed to have a passage resistance higher than that of the second discharge hole.
Immediately after starting the internal combustion engine, the oil level height in the first space is adjusted by the first discharge hole,
When the compression ratio is kept at a predetermined compression ratio, the oil level height in the first space is adjusted by the second discharge hole so that the oil level height in the first space is higher than that immediately after starting. Internal combustion engine characterized by adjustment. The lubricating oil supplied to the first space is the lubricating oil supplied from the housing side to the bearing portion of the housing that rotatably supports the control shaft, via the control shaft side oil passage formed inside the control shaft. Supplied by
Immediately after starting, the amount of lubricating oil that lubricates the control shaft and the bearing portion of the housing is determined by the amount of the lubricating oil between the control shaft and the bearing portion of the housing during cooling to maintain the compression ratio at a predetermined compression ratio. The internal combustion engine according to claim 1 or 2, wherein the amount of lubricating oil to be lubricated is larger than that of the lubricating oil. The partition wall has one end side bearing portion that rotatably supports one end side shaft portion located on one end side of the control shaft,
The housing includes another end side bearing portion that rotatably supports the other end side shaft portion located on the other end side of the control shaft, and a housing side first oil passage that supplies lubricating oil to the one end side bearing portion. A housing-side second oil passage that supplies lubricating oil to the other end-side bearing portion,
Immediately after starting, the amount of lubricating oil that lubricates between the one end side shaft part and the one end side bearing part is the one end side shaft part and the one end side bearing part at the time of cooling when the compression ratio is maintained at a predetermined compression ratio. More than the amount of lubricating oil that lubricates between
Immediately after starting, the amount of lubricating oil that lubricates between the other end side shaft portion and the other end side bearing portion is such that the other end side shaft portion and the other portions during cooling in which the compression ratio is maintained at a predetermined compression ratio. The internal combustion engine according to claim 3, wherein the amount of lubricating oil that lubricates the space between the end side bearing portions is larger than that of the lubricating oil. The housing has a housing-side oil passage that supplies lubricating oil to a bearing portion of the housing,
The control shaft side oil passage is formed so as to open to the shaft portion of the control shaft supported by the bearing portion of the housing,
At the time of cooling in which the compression ratio is maintained at a predetermined compression ratio, the housing side oil passage opening and the control shaft side oil passage opening are formed on the sliding surface between the bearing portion of the housing and the shaft portion of the control shaft. The internal combustion engine according to claim 3, wherein the two are overlapped with each other. The control shaft side oil passage is opened to the one end side passage portion which is supported by the one end side bearing portion and which is opened to the one end side shaft portion, and the other end side shaft portion which is supported by the other end side bearing portion. The other end side passage portion,
When the compression ratio is maintained at a predetermined compression ratio, the opening of the housing-side first oil passage and the opening of the one-end side passage part are formed on the sliding surface between the one-end side bearing part and the one-end side shaft part. The opening of the housing-side second oil passage and the opening of the other-end-side passage portion overlap with each other on the sliding surface of the other-end-side bearing portion and the other-end-side shaft portion. Internal combustion engine according to item 4. The housing has a housing-side oil passage that supplies lubricating oil to a bearing portion of the housing,
The control shaft side oil passage is formed so as to open to the shaft portion of the control shaft supported by the bearing portion of the housing,
When the compression ratio is set when the internal combustion engine is stopped, the opening of the housing-side oil passage and the opening of the control-shaft-side oil passage are formed on the sliding surface between the bearing portion of the housing and the shaft portion of the control shaft. The internal combustion engine according to claim 3 or 5, characterized in that and do not overlap. The housing includes a housing-side first oil passage that supplies lubricating oil to one end-side bearing portion that rotatably supports one end-side shaft portion that is located on one end side of the control shaft, and is located on the other end side of the control shaft. And a housing-side second oil passage that supplies lubricating oil to the other end side bearing portion that rotatably supports the other end side shaft portion,
The control shaft side oil passage has one end side passage portion opened to the one end side shaft portion supported by the one end side bearing portion and the other end opened to the other end side shaft portion supported by the other end side bearing portion. And a side passage portion,
At the compression ratio set when the internal combustion engine is stopped, the opening of the housing-side first oil passage and the opening of the one-end side passage portion are formed on the sliding surface between the one-end side bearing portion and the one-end side shaft portion. Does not overlap, and the opening of the housing-side second oil passage and the opening of the other-end side passage portion do not overlap on the sliding surface between the other-end side bearing portion and the other-end side shaft portion. The internal combustion engine according to claim 3 or 5, which is characterized. A hybrid vehicle having an electric motor as a drive source for a vehicle equipped with an internal combustion engine,
9. The internal combustion engine according to claim 1, wherein the compression ratio set immediately after the start of the internal combustion engine is set to be equal to or lower than the compression ratio set when the engine is cold. A vehicle whose drive source is only an internal combustion engine,
The internal combustion engine according to claim 1, wherein the compression ratio set immediately after the internal combustion engine is started is set to be higher than the compression ratio set when the engine is cold. The compression ratio at the time of cooling becomes a predetermined intermediate compression ratio,
The amount of lubricating oil supplied to the first space at the intermediate compression ratio is greater than the amount of lubricating oil supplied to the first space when the compression ratio is a high compression ratio higher than the intermediate compression ratio. The internal combustion engine according to any one of claims 1 to 10, wherein the number also increases. The compression ratio at the time of cooling becomes a predetermined intermediate compression ratio,
The amount of lubricating oil supplied to the first space at the intermediate compression ratio is greater than the amount of lubricating oil supplied to the first space when the compression ratio is a low compression ratio lower than the intermediate compression ratio. The internal combustion engine according to any one of claims 1 to 11, wherein the number also increases. 13. The oil surface of the lubricating oil in the first space reaches a predetermined prescribed oil surface height during a cold state in which the compression ratio is maintained at a predetermined compression ratio. Internal combustion engine according to. The compression ratio at the time of cooling becomes a predetermined intermediate compression ratio,
The oil level of the lubricating oil in the first space becomes lower than the intermediate compression ratio when the compression ratio is a high compression ratio higher than the intermediate compression ratio. Internal combustion engine according to. The compression ratio at the time of cooling becomes a predetermined intermediate compression ratio,
The oil level of the lubricating oil in the first space is lower than the intermediate compression ratio when the compression ratio is a low compression ratio lower than the intermediate compression ratio. Internal combustion engine according to. 16. The passage resistance of the first discharge hole is set so as to be discharged when the oil temperature of the lubricating oil is the oil temperature after completion of warming up. Internal combustion engine. The passage resistance of the second discharge hole is set such that the lubricating oil is discharged even if the oil temperature of the lubricating oil is the oil temperature during cooling. Internal combustion engine.

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