JP2012163007A - Internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an internal combustion engine that includes a variable compression ratio mechanism in which a crankcase and a cylinder block move relatively, and can supply lubricant from the crankcase to the cylinder block.SOLUTION: The internal combustion engine includes: the variable compression ratio mechanism formed to allow the cylinder block 2 to move relative to the crankcase 79; and an oil path connection mechanism 60 connecting an oil path of the crankcase 79 with an oil path of the cylinder block 2. The oil path connection mechanism 60 includes: a block side oil pipe 76 communicating with the oil path of the cylinder block 2; and a crankcase side oil pipe 75 communicating with the oil path of the crankcase 79. The block side oil pipe 76 and the crankcase side oil pipe 75 are formed to oppose each other to fit, and slide each other according to the relative movement of the cylinder block 2 to the crankcase 79.

Description

  The present invention relates to an internal combustion engine.

  In the combustion chamber of the internal combustion engine, the air-fuel mixture is ignited in a compressed state. It is known that the compression ratio when compressing the air-fuel mixture affects the output torque and the fuel consumption. By increasing the compression ratio, the output torque can be increased or the fuel consumption can be reduced. On the other hand, it is known that if the compression ratio is too high, abnormal combustion such as knocking occurs. In the prior art, an internal combustion engine having a variable compression ratio mechanism capable of changing the compression ratio during an operation period is known. Lubricating oil is supplied to a predetermined part of the internal combustion engine.

  Japanese Patent Laid-Open No. 2005-140090 discloses an internal combustion engine having a variable compression ratio that includes a cam mechanism between a cylinder block and a crankcase and changes the compression ratio by relatively moving the crankcase and the cylinder block. It is disclosed. The cam mechanism has an eccentric shaft, and relatively moves the crankcase and the cylinder block by rotating the eccentric shaft. In this internal combustion engine, the lubricating oil supply passage for supplying the lubricating oil stored in the oil pan to the cylinder head includes a crankcase passage portion that passes through the crankcase, a cylinder block passage portion that passes through the cylinder block, and these A cam mechanism passing portion that passes through the cam mechanism between the passing portions. In the cam mechanism passage part, a lubricating oil flow path is provided inside or on the surface of the cam shaft, and the lubricating oil is supplied from the crankcase passage part to the cylinder block passage part by passing through the cam mechanism. Is disclosed.

  Japanese Patent Laid-Open No. 2005-69181 discloses an internal combustion engine having a variable compression ratio that changes a compression ratio of an internal combustion engine by driving a control shaft that is supported by a bearing portion and connected to a mechanical element of the internal combustion engine. Has been. This publication discloses that the amount of lubricating oil supplied to the control shaft or the bearing portion is increased immediately before changing the compression ratio of the internal combustion engine. Further, a lubricating oil supply main pipe to which the lubricating oil stored in the oil pan is pressurized by a pump and the pressurized lubricating oil is sent is disposed outside the engine body of the internal combustion engine. It is disclosed that the lubricating oil sent to the lubricating oil supply main is supplied to the bearing portion of the crankshaft.

JP-A-2005-140090 JP 2005-69181 A JP 2010-185393 A JP 2005-90270 A JP 2009-24656 A JP 2009-62865 A

  In an engine body of an internal combustion engine, lubricating oil is supplied to a support portion of a crankshaft, a support portion of a camshaft, and the like. In an internal combustion engine equipped with a variable compression ratio mechanism in which the relative distance between the crankcase and the cylinder block varies, the lubricating oil stored in the oil pan below the crankcase is supplied to the cylinder block, cylinder head, etc. There is a need to. That is, it is necessary to supply lubricating oil to members whose distances vary.

  In the internal combustion engine disclosed in Japanese Patent Laid-Open No. 2005-140090, an oil passage is formed on a support shaft (cam shaft) of a cylinder block included in a variable compression ratio mechanism, and lubricating oil is supplied from the crankcase to the cylinder block. Supply. This publication discloses a sliding bearing as a bearing for the support shaft. In this internal combustion engine, when the bearing of the support shaft is changed to a rolling bearing, the amount of lubricating oil leaked at the bearing portion increases, and the hydraulic pressure greatly decreases. For this reason, if the bearing portion is changed to a rolling bearing, there is a possibility that the lubricating oil cannot be sufficiently supplied to each part. Or in order to enlarge the discharge flow rate of the pump for supplying lubricating oil, the necessity of attaching a large sized pump arises.

  Furthermore, there is a problem that the holes and grooves formed in the support shaft for supplying the lubricating oil are difficult to increase because they are limited by the diameter of the support shaft and the width of the bearing portion. For this reason, a case where a sufficient amount of lubricating oil cannot be supplied occurs. Alternatively, it is necessary to enlarge the support shaft or enlarge the pump for supplying the lubricating oil.

  As disclosed in the above Japanese Patent Application Laid-Open No. 2005-69181, by providing a lubricating oil supply path outside the engine body, that is, outside the crankcase or cylinder head, without the support shaft of the cylinder block. Lubricating oil can be supplied from the crankcase to the cylinder block and the cylinder head. However, in this internal combustion engine, there is a problem that a space for arranging the piping is separately required in order to arrange the piping for supplying the lubricating oil outside the engine body.

  An object of the present invention is to provide an internal combustion engine having a variable compression ratio mechanism in which a lower structure including a crankcase and a cylinder block move relatively, and capable of supplying lubricating oil from the lower structure to the cylinder block. To do.

  An internal combustion engine of the present invention includes a crankcase, and has a lower structure having an oil passage through which lubricating oil flows therein, an upper passage disposed in the lower structure, and an oil passage through which lubricating oil flows. The cylinder block which has inside. The internal combustion engine is further formed so that the cylinder block moves relative to the lower structure, and the cylinder block moves away from the lower structure, thereby increasing the volume of the combustion chamber and increasing the compression ratio. And a variable compression ratio mechanism, and an oil passage connection mechanism for connecting the oil passage of the lower structure to the oil passage of the cylinder block. The oil passage connection mechanism has an upper connection portion that communicates with the oil passage of the cylinder block and a lower connection portion that communicates with the oil passage of the lower structure. The upper connection portion and the lower connection portion are formed so as to be opposed to each other, slide with each other according to the relative movement of the cylinder block with respect to the lower structure, and the length of the oil passage connection mechanism is variable. Is formed.

  In the above invention, the oil passage connection mechanism is preferably disposed in a region where the lower structure and the cylinder block face each other in a space in which the lubricating oil is enclosed.

  In the above invention, the cylinder head is disposed above the cylinder block and has an oil passage through which lubricating oil flows. The oil passage of the cylinder head is connected to the oil passage of the cylinder block, and the compression ratio variable mechanism Includes a support shaft for supporting the cylinder block with respect to the lower structure, and the oil passage of the cylinder block is lubricated from the oil passage of the lower structure toward the oil passage of the cylinder head without passing through the support shaft of the cylinder block. It is preferable to be configured to supply oil.

  In the above invention, the upper connection portion has a block-side oil pipe fixed to the cylinder block, and the lower connection portion has a crankcase-side oil pipe fixed to the crankcase. The crankcase side oil pipe can be formed so as to fit and slide with each other.

  According to the present invention, it is possible to provide an internal combustion engine including a variable compression ratio mechanism in which a lower structure including a crankcase and a cylinder block move relatively, and capable of supplying lubricating oil from the lower structure to the cylinder block. it can.

1 is a schematic view of an internal combustion engine in an embodiment. 1 is a schematic exploded perspective view of a compression ratio variable mechanism of an internal combustion engine in an embodiment. It is a schematic sectional drawing of the part of a cylinder block and a crankcase when the internal combustion engine in embodiment becomes a high compression ratio. It is a schematic sectional drawing of the part of a cylinder block and a crankcase when the internal combustion engine in embodiment becomes a low compression ratio. It is a schematic sectional drawing of the engine main body explaining the lubricating oil supply apparatus in embodiment. It is a 1st expansion schematic sectional view of the oil passage connection mechanism which connects the oil passage of a crankcase and the oil passage of a cylinder block in an embodiment. It is a 2nd expansion schematic sectional drawing of the oil-path connection mechanism which connects the oil path of a crankcase and the oil path of a cylinder block in embodiment. It is an expansion schematic sectional drawing of the other oil-path connection mechanism which connects the oil path of a crankcase and the oil path of a cylinder block in embodiment.

  The internal combustion engine in the embodiment will be described with reference to FIGS. In the present embodiment, an internal combustion engine disposed in a vehicle will be described as an example.

  FIG. 1 is a schematic view of an internal combustion engine in the present embodiment. The internal combustion engine in the present embodiment is a spark ignition type. The internal combustion engine includes an engine body 1. The engine body 1 includes a cylinder block 2 and a cylinder head 4. A piston 3 is disposed inside the cylinder block 2. The piston 3 reciprocates inside the cylinder block 2.

  The combustion chamber 5 is formed for each cylinder. An engine intake passage and an engine exhaust passage are connected to the combustion chamber 5. The engine intake passage is a passage for supplying air or a mixture of fuel and air to the combustion chamber 5. The engine exhaust passage is a passage for discharging exhaust gas generated by the combustion of fuel from the combustion chamber 5.

  An intake port 7 and an exhaust port 9 are formed in the cylinder head 4. The intake valve 6 is disposed at the end of the intake port 7 and is configured to be able to open and close the engine intake passage communicating with the combustion chamber 5. The exhaust valve 8 is disposed at the end of the exhaust port 9 and is configured to be able to open and close the engine exhaust passage communicating with the combustion chamber 5. A spark plug 10 as an ignition device is fixed to the cylinder head 4. The spark plug 10 is formed to ignite fuel in the combustion chamber 5.

  The internal combustion engine in the present embodiment includes a fuel injection valve 11 for supplying fuel to the combustion chamber 5. The fuel injection valve 11 in the present embodiment is arranged so as to inject fuel into the intake port 7. The fuel injection valve 11 is not limited to this configuration, and may be arranged so that fuel can be supplied to the combustion chamber 5. For example, the fuel injection valve may be arranged to inject fuel directly into the combustion chamber.

  The fuel injection valve 11 is connected to the fuel tank 28 via an electronically controlled fuel pump 29 with variable discharge amount. The fuel stored in the fuel tank 28 is supplied to the fuel injection valve 11 by the fuel pump 29.

  The intake port 7 of each cylinder is connected to a surge tank 14 via a corresponding intake branch pipe 13. The surge tank 14 is connected to an air cleaner (not shown) via an intake duct 15 and an air flow meter 16. An air flow meter 16 that detects the amount of intake air is connected to the intake duct 15. A throttle valve 18 driven by a step motor 17 is disposed inside the intake duct 15. On the other hand, the exhaust port 9 of each cylinder is connected to a corresponding exhaust branch pipe 19. The exhaust branch pipe 19 is connected to the exhaust treatment device 21. The exhaust treatment device 21 in the present embodiment includes an oxidation catalyst 20. The exhaust treatment device 21 is connected to the exhaust pipe 22.

  The internal combustion engine in the present embodiment includes an electronic control unit 31. The electronic control unit 31 in the present embodiment includes a digital computer. The electronic control unit 31 includes a RAM (random access memory) 33, a ROM (read only memory) 34, a CPU (microprocessor) 35, an input port 36 and an output port 37 which are connected to each other via a bidirectional bus 32. .

  The air flow meter 16 generates an output voltage proportional to the amount of intake air taken into the combustion chamber 5. This output voltage is input to the input port 36 via the corresponding AD converter 38. A load sensor 41 is connected to the accelerator pedal 40. The load sensor 41 generates an output voltage proportional to the depression amount of the accelerator pedal 40. This output voltage is input to the input port 36 via the corresponding AD converter 38.

  The crank angle sensor 42 generates an output pulse each time the crankshaft rotates, for example, a predetermined angle, and this output pulse is input to the input port 36. The engine speed can be detected from the output of the crank angle sensor 42. Further, the crank angle can be detected from the output of the crank angle sensor 42. In the engine exhaust passage, a temperature sensor 43 as a temperature detector that detects the temperature of the exhaust treatment device 21 is disposed downstream of the exhaust treatment device 21. The output of the temperature sensor 43 is input to the input port 36 via the corresponding AD converter 38.

  The output port 37 of the electronic control unit 31 is connected to the fuel injection valve 11 and the spark plug 10 via the corresponding drive circuits 39. The electronic control unit 31 in the present embodiment is formed to perform fuel injection control and ignition control. That is, the fuel injection timing and the fuel injection amount are controlled by the electronic control unit 31. Further, the ignition timing of the spark plug 10 is controlled by the electronic control unit 31. The output port 37 is connected to a step motor 17 and a fuel pump 29 that drive the throttle valve 18 via a corresponding drive circuit 39. These devices are controlled by the electronic control unit 31.

  The intake valve 6 is formed to open and close as the intake cam 51 rotates. The exhaust valve 8 is formed to open and close as the exhaust cam 52 rotates. The internal combustion engine in the present embodiment includes a variable valve mechanism. The variable valve mechanism includes a variable valve timing device 53 that changes the opening / closing timing of the intake valve 6. The variable valve timing device 53 in the present embodiment is connected to the rotation shaft of the intake cam 51. The variable valve timing device 53 is controlled by the electronic control unit 31.

  The internal combustion engine in the present embodiment includes a variable compression ratio mechanism. In the present invention, the space in the cylinder surrounded by the crown surface of the piston and the cylinder head when the piston reaches compression top dead center is referred to as a combustion chamber. The compression ratio of the internal combustion engine is determined depending on the volume of the combustion chamber and the like. The variable compression ratio mechanism in the present embodiment is formed to change the compression ratio by changing the volume of the combustion chamber. The compression ratio of the internal combustion engine is expressed by (compression ratio) = (combustion chamber volume + piston stroke volume when the intake valve is closed) / (combustion chamber volume).

  FIG. 2 is an exploded perspective view of the compression ratio variable mechanism of the internal combustion engine in the present embodiment. FIG. 3 is a first schematic cross-sectional view of the combustion chamber portion of the internal combustion engine. FIG. 3 is a schematic diagram when a high compression ratio is obtained by the variable compression ratio mechanism. In the internal combustion engine in the present embodiment, the lower structure including the crankcase and the cylinder block arranged on the upper side of the lower structure move relative to each other. The substructure in the present embodiment supports the cylinder block via a compression ratio variable mechanism. Further, the lower structure in the present embodiment supports the crankshaft.

  2 and 3, a plurality of protrusions 80 are formed below the side walls on both sides of the cylinder block 2. The protrusion 80 is formed with a cam insertion hole 81 having a circular cross section. A plurality of protrusions 82 are formed on the upper wall of the crankcase 79. The protrusion 82 is formed with a cam insertion hole 83 having a circular cross-sectional shape. The protrusion 82 of the crankcase 79 is fitted between the protrusions 80 of the cylinder block 2.

  The variable compression ratio mechanism in the present embodiment includes a pair of camshafts 84 and 85 as support shafts for the cylinder block 2. Each camshaft 84, 85 includes a circular cam 86 that is rotatably inserted into the cam insertion hole 81. These circular cams 86 are arranged coaxially with the rotation shafts of the cam shafts 84 and 85.

  On the other hand, as shown in FIG. 3, eccentric shafts 87 arranged eccentrically with respect to the rotation shafts of the respective cam shafts 84 and 85 extend between the circular cams 86. A circular cam 88 is eccentrically attached to the eccentric shaft 87 so as to be rotatable. The circular cam 88 is disposed between the circular cams 86. These circular cams 88 are rotatably supported in the corresponding cam insertion holes 83.

  The compression ratio variable mechanism includes a motor 89. Two worm gears 91 and 92 having spiral directions opposite to each other are attached to the rotating shaft 90 of the motor 89. Gears 93 and 94 are fixed to the end portions of the camshafts 84 and 85, respectively. The gears 93 and 94 are arranged so as to mesh with the worm gears 91 and 92. When the motor 89 rotates the rotating shaft 90, the camshafts 84 and 85 can be rotated in directions opposite to each other.

  Referring to FIG. 3, when the circular cams 86 arranged on the respective cam shafts 84 and 85 are rotated in opposite directions as indicated by arrows 96, the eccentric shaft 87 moves toward the lower end. The circular cam 88 rotates in the opposite direction to the circular cam 86 as indicated by an arrow 97 in the cam insertion hole 83.

  FIG. 4 shows a second schematic cross-sectional view of the combustion chamber portion of the internal combustion engine in the present embodiment. FIG. 4 is a schematic diagram when a low compression ratio is achieved by the compression ratio variable mechanism. As shown in FIG. 4, when the eccentric shaft 87 moves to the lower end, the central axis of the circular cam 88 moves below the eccentric shaft 87. Referring to FIGS. 3 and 4, the relative position between crankcase 79 and cylinder block 2 is determined by the distance between the central axis of circular cam 86 and the central axis of circular cam 88. The cylinder block 2 moves away from the crankcase 79 as the distance between the central axis of the circular cam 86 and the central axis of the circular cam 88 increases. As the cylinder block 2 moves away from the crankcase 79 as indicated by an arrow 98, the volume of the combustion chamber 5 when the piston 3 reaches the compression top dead center increases.

  In the variable compression ratio mechanism in the present embodiment, the volume of the combustion chamber is variably formed by moving the cylinder block relative to the crankcase. In FIG. 3, the piston 3 has reached the compression top dead center, and the volume of the combustion chamber 5 is reduced. In this state, the compression ratio increases. On the other hand, in FIG. 4, the piston 3 reaches the compression top dead center, and the volume of the combustion chamber 5 is increased. In this state, the compression ratio becomes small. Thus, the internal combustion engine in the present embodiment can change the compression ratio during the operation period. For example, the compression ratio can be changed by a variable compression ratio mechanism according to the operating state of the internal combustion engine.

  The variable compression ratio mechanism according to the present embodiment moves the cylinder block relative to the crankcase by rotating a circular cam whose eccentric shaft is eccentric. However, the present invention is not limited to this configuration. In contrast, any compression ratio variable mechanism that can change the compression ratio by moving the cylinder block can be employed.

  The compression ratio variable mechanism in the present embodiment is covered with a cover member (not shown), and is formed so that the space inside the cylinder bore and the crankcase is sealed. That is, the internal combustion engine is formed so that the lubricating oil is sealed inside the engine body and does not leak outside the engine body.

  An internal combustion engine generally has a lower thermal efficiency as the engine load is lower. Therefore, in order to improve the thermal efficiency during operation of the internal combustion engine, it is preferable to improve the thermal efficiency when the load is low. Thermal efficiency can be improved by increasing the compression ratio with the variable compression ratio mechanism in the present embodiment. In particular, when the compression ratio is increased, the expansion ratio when the piston moves from the top dead center to the bottom dead center is increased, so that the thermal efficiency is improved. However, when the compression ratio is increased by the compression ratio variable mechanism, abnormal combustion such as knocking occurs at a predetermined compression ratio.

  The internal combustion engine in the present embodiment includes a variable valve mechanism, and the opening / closing timing of the intake valve is variably formed. By delaying the timing of closing the intake valve, the amount of air flowing into the combustion chamber can be reduced. That is, by delaying the timing for closing the intake valve, the actual compression ratio at which the air-fuel mixture is compressed in the combustion chamber can be reduced.

  In the internal combustion engine of this embodiment, when the load is low, the mechanical compression ratio is controlled to be high by the variable compression ratio mechanism. That is, control is performed so that the volume of the combustion chamber is reduced when the piston reaches the compression top dead center. On the other hand, the occurrence of knocking or the like can be suppressed by delaying the timing of closing the intake valve by the variable valve mechanism and controlling so that the actual compression ratio does not become too high. Even if the timing for closing the intake valve is delayed, the expansion ratio remains large, so that the thermal efficiency can be improved. As described above, the internal combustion engine in the present embodiment can improve the thermal efficiency by increasing the expansion ratio while maintaining the actual compression ratio in the combustion chamber below the compression ratio at which abnormal combustion occurs.

  FIG. 5 is a schematic cross-sectional view of the engine main body for explaining an oil passage for supplying lubricating oil to each part of the engine main body in the present embodiment. The internal combustion engine in the present embodiment includes a lubricating oil supply device that supplies lubricating oil to each part of the engine body.

  The lower structure in the present embodiment includes an oil pan 66 fixed to the crankcase 79. Lubricating oil is stored at the bottom of the oil pan 66. The piston 3 is supported on the crankshaft 62 via a connecting rod 62. In the space surrounded by the crankcase 79 and the oil pan 66, the crankshaft 62 rotates.

  The lubricating oil supply device in the present embodiment includes an oil pump 64 that sucks up and pressurizes lubricating oil stored in the oil pan 66. In the oil pump 64 in the present embodiment, the rotational force of the crankshaft 62 is transmitted via the drive chain 65. The oil pump 64 pressurizes the lubricating oil by the rotational force transmitted by the drive chain 65. The oil pump is not limited to this form, and any oil pump may be used as long as it can pressurize the lubricating oil.

  The lubricating oil supply device in the present embodiment has an oil strainer 63 and an oil filter 67. The oil strainer 63 removes large foreign matters contained in the lubricating oil. The oil filter 67 removes small foreign matters contained in the lubricating oil.

  When the oil pump 64 is driven, the lubricating oil stored at the bottom of the oil pan 66 flows into the oil pump 64 through the oil strainer 63 as indicated by an arrow 101. The lubricating oil pressurized by the oil pump 64 flows into the oil filter 67 as indicated by the arrow 102.

  An oil path through which lubricating oil flows is formed inside the cylinder block 2. The oil passage of the cylinder block 2 in the present embodiment includes a main oil gallery 71 as a main oil passage. The lubricating oil that has circulated through the oil filter 67 is supplied to the main oil gallery 71 as indicated by an arrow 103.

  In the internal combustion engine of the present embodiment, the lubricating oil is supplied from the main oil gallery 71 to each part of the engine body 1. For example, in a member disposed inside the crankcase 79, as indicated by an arrow 104, lubricating oil is supplied to a crank journal portion that rotatably supports the crankshaft 62. Lubricating oil is supplied to the large end of the connecting rod 62, the drive chain 65 that drives the oil pump 64, and the like.

  Cylinder block 2 in the present embodiment includes an in-block oil passage 72 through which lubricating oil flows. The in-block oil passage 72 is formed inside the cylinder block 2. The in-block oil passage 72 in the present embodiment penetrates from the lower surface of the cylinder block 2 toward the upper surface.

  The internal combustion engine in the present embodiment includes an oil passage connection mechanism 60 that connects an oil passage formed in the crankcase 79 and an oil passage formed in the cylinder block 2. The oil passage connection mechanism 60 in the present embodiment connects a main oil gallery 71 formed in the crankcase 79 and an in-block oil passage 72 formed in the cylinder block 2. The oil passage connection mechanism 60 is disposed in a region where the cylinder block 2 and the crankcase 79 face each other. Referring to FIGS. 2 and 5, oil passage connection mechanism 60 in the present embodiment is arranged at a portion of notch 79 a formed in crankcase 79.

  FIG. 6 shows an enlarged schematic cross-sectional view of the oil passage connection mechanism in the present embodiment. The oil passage connection mechanism 60 includes a crankcase-side oil pipe 75 as a lower connection portion communicating with an oil passage inside the lower structure. The crankcase side oil pipe 75 is fixed to the crankcase 79. The crankcase side oil pipe 75 is disposed so as to communicate with the main oil gallery 71. The crankcase side oil pipe 75 is arranged so as to protrude from the surface of the crankcase 79 toward the cylinder block 2.

  The oil passage connection mechanism 60 includes a block-side oil pipe 76 as an upper communication portion that communicates with an oil passage inside the cylinder block 2. The block side oil pipe 76 is fixed to the cylinder block 2. The block-side oil pipe 76 is disposed so as to communicate with the in-block oil passage 72. The block side oil pipe 76 is arranged so as to protrude from the surface of the cylinder block 2 toward the crankcase 79. The crankcase side oil pipe 75 and the block side oil pipe 76 are arranged coaxially and are engaged with each other. When the cylinder block 2 moves with respect to the crankcase 79 by the variable compression ratio mechanism, for example, as indicated by an arrow 98, the crankcase side oil pipe 75 and the block side oil pipe 76 slide relative to each other. Is formed.

  A sealing member is provided at a contact portion between the crankcase side oil pipe 75 and the block side oil pipe 76 so as to prevent the lubricating oil from leaking. In the present embodiment, an O-ring 77 is disposed at a portion where the crankcase side oil pipe 75 and the block side oil pipe 76 slide relative to each other. The sealing member is not limited to the O-ring, and any member that suppresses the leakage of the lubricating oil from a portion where the upper connection portion and the lower connection portion slide can be employed.

  Referring to FIGS. 5 and 6, the lubricating oil supplied to main oil gallery 71 passes through crankcase side oil pipe 75 and block side oil pipe 76, as shown by arrow 105, and the head of cylinder head 4. It is supplied to the inner oil passage 73.

  FIG. 7 shows an enlarged schematic cross-sectional view of the oil passage connection mechanism when the compression ratio variable mechanism is driven and the cylinder block moves away from the crankcase. As indicated by an arrow 98, when the cylinder block 2 moves away from the crankcase 79, the block-side oil pipe 76 slides relative to the crankcase-side oil pipe 75. Similarly, when the cylinder block 2 moves toward the crankcase 79, the block-side oil pipe 76 slides relative to the crankcase-side oil pipe 75. For this reason, even if the compression ratio variable mechanism is driven, the connection between the main oil gallery 71 and the oil passage 72 in the block can be maintained. Thus, in the internal combustion engine in the present embodiment, the length of the oil passage connection mechanism 60 is variably formed.

  The oil passage connection mechanism in the present embodiment can supply the lubricating oil from the oil passage of the crankcase to the oil passage of the cylinder block even if the cylinder block moves relative to the crankcase and the mutual distance changes. . The oil path connection mechanism in the present embodiment can continuously supply lubricating oil to the cylinder block regardless of the relative position of the cylinder block with respect to the crankcase. For example, the lubricating oil can be supplied even during a period in which the variable compression ratio mechanism is driven and the cylinder block is moving relative to the crankcase.

  Referring to FIG. 5, the internal combustion engine in the present embodiment supplies lubricating oil from the oil passage of crankcase 79 to the oil passage of cylinder block 2 without using cam shafts 84 and 85 as support shafts of the cylinder block. Can be supplied. For this reason, it is possible to avoid a reduction in the cross-sectional area of the oil passage for supplying the lubricating oil, and supply a sufficient amount of lubricating oil from the oil passage of the crankcase 79 toward the oil passage of the cylinder block 2. Can do. Alternatively, a sufficient amount of lubricating oil can be supplied to the oil passage of the cylinder block 2 without requiring a large discharge pressure of the oil pump. In addition, a sufficient amount of lubricating oil can be supplied to the cylinder block 2 without providing piping outside the engine body.

  Alternatively, the in-block oil passage 72 of the cylinder block 2 in the present embodiment is connected to the in-head oil passage 73 formed inside the cylinder head 4. The internal combustion engine in the present embodiment can supply a sufficient amount of lubricating oil from the oil passage of the crankcase 79 to the oil passage of the cylinder head 4. Alternatively, the lubricating oil can be supplied from the crankcase to the cylinder head without requiring a large discharge pressure of the oil pump.

  Or the internal combustion engine in this Embodiment can employ | adopt a rolling bearing as a bearing of the support shaft of a cylinder block. In the case of an internal combustion engine that supplies lubricating oil from the crankcase to the cylinder block through the rolling bearing portion, leakage of the lubricating oil increases at the rolling bearing portion, and the hydraulic pressure is greatly reduced. For this reason, there is a possibility that a sufficient amount of lubricating oil cannot be supplied to each part. By adopting the oil passage connection mechanism of the present embodiment, the lubricating oil can be supplied from the oil passage of the crankcase 79 to the oil passage of the cylinder block 2 without passing through the support shaft of the cylinder block. Even if it employ | adopts, sufficient quantity of lubricating oil can be supplied to each site | part.

  In the internal combustion engine of the present embodiment, the lubricating oil can be supplied to the bearing portion of the support shaft of the cylinder block 2 from at least one of the main oil gallery 71 and the oil passage 72 in the block. Further, by adopting a rolling bearing as the bearing of the cylinder block, the resistance when the compression ratio variable mechanism is driven is reduced, and the responsiveness of the compression ratio variable mechanism is improved. Alternatively, the driving torque for driving the variable compression ratio mechanism can be reduced, and the drive device for the variable compression ratio mechanism can be reduced in size.

  Furthermore, the engine main body in the present embodiment is covered with a covering member so that the lubricating oil does not leak to the outside, and the lubricating oil is enclosed. The oil passage connection mechanism in the present embodiment is arranged in a region where the crankcase and the cylinder head face each other in the space in which the lubricating oil is enclosed. By disposing the oil passage connection mechanism in this region, the oil passage connection mechanism can be blocked from the outside air. On the other hand, it is also possible to arrange the oil passage connection mechanism outside the engine body. That is, it is also possible to arrange an oil passage connection mechanism in the atmosphere. However, in this case, foreign matters such as dust may enter the sliding portion of the oil passage connection mechanism, which may deteriorate the sliding characteristics and cause a large amount of lubricating oil to leak. Since the oil passage connection mechanism according to the present embodiment is disposed in a space that is blocked from outside air, it is possible to avoid contamination of foreign matters in the sliding portion. Furthermore, since the lubricating oil that has passed through the oil strainer and the oil filter is supplied to the oil path connection mechanism, it is possible to prevent foreign matter from entering the sliding portion.

  The lubricating oil supply device in the present embodiment supplies lubricating oil to the head internal oil passage 73 of the cylinder head 4 via the block internal oil passage 72 formed inside the cylinder block 2. The lubricating oil supplied to the in-head oil passage 73 can be supplied to each member disposed in the cylinder head 4. For example, lubricating oil can be supplied to a cam journal portion that supports a camshaft including a cam that drives an intake valve and an exhaust valve, or a variable valve mechanism.

  The in-block oil passage 72 formed in the cylinder block 2 may be formed so as to supply lubricating oil to each member of the engine body. For example, the oil passage 72 in the block is a supply pipe that supplies lubricating oil to the camshafts 84 and 85 serving as support shafts of the cylinder block 2 or an oil jet pipe that injects lubricating oil to a sliding portion between the piston 3 and the cylinder bore. It does not matter if it is connected to.

  In the oil passage connection mechanism in the present embodiment, the upper connection portion arranged in the cylinder block and the lower connection portion arranged in the lower structure are each formed in a tubular shape, but this is not the only form. However, any structure can be adopted as long as the upper connecting portion and the lower connecting portion are fitted to each other and are slid according to the relative movement between the cylinder block and the lower structure. .

  FIG. 8 shows a schematic cross-sectional view of another oil passage connection mechanism in the present embodiment. Another oil passage connection mechanism 60 includes a recess 78 formed in the cylinder block 2. The concave portion 78 functions as an upper connection portion. The crankcase side oil pipe 75 is fixed to the crankcase 79. In another oil path connection mechanism 60, the crankcase side oil pipe 75 is formed long so as to extend to the inside of the cylinder block 2.

  The concave portion 78 of the cylinder block 2 is fitted to face the crankcase side oil pipe 75. Further, as indicated by an arrow 98, when the cylinder block 2 moves relative to the crankcase 79, the concave portion 78 is formed to slide with respect to the crankcase-side oil pipe 75. The length of the oil passage connection mechanism 60 is formed to change. Thus, either one of the upper connection portion and the lower connection portion may include a recess.

  Although the upper connection part in this Embodiment is connected to the oil path in a block which penetrates a cylinder block, it is not restricted to this form, An upper connection part can be connected to the arbitrary oil paths of a cylinder block. Further, the lower connection portion in the present embodiment is connected to the main oil gallery of the crankcase, but is not limited to this form, and the lower connection portion can be connected to an arbitrary oil passage of the lower structure. it can.

  The internal combustion engine in the present embodiment includes a variable valve mechanism that changes the closing timing of the intake valve in addition to the compression ratio variable mechanism that changes the volume of the combustion chamber when the piston reaches compression top dead center. However, the present invention is not limited to this embodiment, and the present invention can be applied to an internal combustion engine that does not include a variable valve mechanism.

  In the respective drawings described above, the same or corresponding parts are denoted by the same reference numerals. In addition, said embodiment is an illustration and does not limit invention. In the embodiment, the change shown in a claim is included.

DESCRIPTION OF SYMBOLS 1 Engine body 2 Cylinder block 3 Piston 4 Cylinder head 5 Combustion chamber 60 Oil path connection mechanism 64 Oil pump 71 Main oil gallery 72 Block oil path 73 Head oil path 75 Crankcase side oil pipe 76 Block side oil pipe 77 O-ring 78 Concavity 79 Crankcase 84, 85 Camshaft 86 Circular cam 87 Eccentric shaft 88 Circular cam 89 Motor

Claims (4)

A lower structure including a crankcase and having an oil passage through which lubricating oil flows;
A cylinder block which is disposed on the upper side of the lower structure and has a hole portion where a piston is disposed and an oil passage through which lubricating oil flows;
The compression ratio is variable so that the cylinder block moves relative to the lower structure, and the cylinder block moves away from the lower structure to increase the combustion chamber volume and reduce the compression ratio. Mechanism,
An oil passage connection mechanism for connecting the oil passage of the substructure to the oil passage of the cylinder block,
The oil passage connection mechanism has an upper connection portion that communicates with the oil passage of the cylinder block, and a lower connection portion that communicates with the oil passage of the lower structure,
The upper connection portion and the lower connection portion are formed so as to be opposed to each other, slide with each other according to the relative movement of the cylinder block with respect to the lower structure, and the length of the oil passage connection mechanism is variable. An internal combustion engine characterized by being formed.   2. The internal combustion engine according to claim 1, wherein the oil passage connection mechanism is disposed in a region in which the lower structure and the cylinder block face each other in a space in which the lubricating oil is enclosed. The cylinder head is disposed on the upper side of the cylinder block and has an oil passage through which lubricating oil flows.
The oil path of the cylinder head is connected to the oil path of the cylinder block,
The variable compression ratio mechanism includes a support shaft that supports the cylinder block with respect to the lower structure,
The oil passage of the cylinder block is formed so as to supply lubricating oil from the oil passage of the lower structure toward the oil passage of the cylinder head without passing through the support shaft of the cylinder block. The internal combustion engine according to 1 or 2.   The upper connection part has a block side oil pipe fixed to the cylinder block, and the lower connection part has a crank case side oil pipe fixed to the crankcase, the block side oil pipe and the crankcase side oil pipe The internal combustion engine according to any one of claims 1 to 3, wherein and are fitted and slid with each other.

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