JP4103731B2 - Variable compression ratio internal combustion engine - Google Patents

Description

  The present invention relates to a variable compression ratio internal combustion engine in which a compression ratio is variable by changing a combustion chamber volume.

  In recent years, a technique for changing the compression ratio of an internal combustion engine has been proposed for the purpose of improving the fuel efficiency performance and output performance of the internal combustion engine. In these techniques, by utilizing the pressure of lubricating oil, so-called hydraulic pressure, an engine element constituting a combustion chamber of an internal combustion engine, or an element connected to the engine element (hereinafter simply referred to as “engine element of an internal combustion engine”). And the compression ratio of the internal combustion engine is changed.

  For example, when changing the compression ratio of an internal combustion engine using oil pressure, a technique for providing a valve that opens a drain passage of a hydraulic passage of the mechanism to the atmosphere side is disclosed (for example, see Patent Document 1). ). In addition, an eccentric bearing is provided between the connecting rod and the crank pin, and the friction between the connecting rod and the eccentric bearing is controlled when the compression ratio of the internal combustion engine is changed by rotating the eccentric bearing with respect to the crank pin. In order to do this, a technique using hydraulic pressure is disclosed (for example, see Patent Document 2).

Further, as a technique for changing the compression ratio of an internal combustion engine without using hydraulic pressure, a control shaft coupled to the engine element of the internal combustion engine is rotationally driven by an electric motor so that those engine elements, for example, a crankcase and a cylinder block Has been disclosed to change the compression ratio of the internal combustion engine (see, for example, Patent Document 3).
Japanese Utility Model Publication No. 63-83440 JP 2000-64866 A JP 2003-206871 A Japanese Utility Model Publication No. 63-164534 Japanese Patent Laid-Open No. 11-62648 JP-A-4-301148

  Here, when the engine element of the internal combustion engine is driven by the rotationally driven control shaft to change the compression ratio of the internal combustion engine, the sliding portion is brought into contact with the control shaft, particularly the bearing portion of the control shaft. The site exists. Therefore, it is necessary to supply lubricating oil to the sliding portion in order to suppress wear of the control shaft or the bearing portion.

However, if lubricating oil is constantly supplied to the sliding portion, wear on the control shaft or the bearing portion can be suppressed, but an internal combustion engine that supplies lubricating oil, for example, an internal combustion engine that supplies a lubricating oil to drive a pump. There is a risk that the load on the engine will increase. In addition, when the supply of lubricating oil is insufficient, the lubricating oil interposed between the control shaft and the bearing portion that is the contact element is not sufficiently secured, so the control shaft, the bearing portion, etc. There is a concern that the compression ratio of the internal combustion engine may not be changed satisfactorily due to intense wear or seizure.

  In the present invention, in view of the above-described problems, in an internal combustion engine in which an engine element of an internal combustion engine is driven by a rotationally driven control shaft and the compression ratio is changed, lubricating oil is appropriately supplied to the control shaft and its contact portion. Accordingly, it is an object of the present invention to suppress wear on the contact portion such as the control shaft and its bearing portion and reduce the load on the internal combustion engine due to the supply of lubricating oil.

  In order to solve the above-described problems, the present invention provides a control shaft for driving an engine element of an internal combustion engine and a contact portion thereof immediately before or at the start of the change of the compression ratio of the internal combustion engine by the compression ratio control means. We focused on supplying lubricant to a bearing. As a result, the static frictional force at the start of the rotational drive of the control shaft is reduced, and after the rotational drive, the control shaft is brought into a hydrodynamic bearing state so that the lubricating oil can be supplied to the control shaft and the bearing portion as much as possible. This is because it is possible to reduce the weight.

  Therefore, the present invention provides a variable compression ratio internal combustion engine in which the compression ratio is variable, by driving a control shaft that is supported by a bearing and connected to an engine element of the internal combustion engine, thereby reducing the compression ratio of the internal combustion engine. The compression ratio control means to be changed, the lubricating oil supply means for supplying lubricating oil to the control shaft or the bearing portion, and a predetermined period immediately before starting the change of the compression ratio of the internal combustion engine or at the start of the change, Lubricating oil supply control means for increasing the amount of lubricating oil supplied to the control shaft or the bearing by the lubricating oil supply means from the amount of lubricating oil supplied when the control shaft is stopped.

  In the above variable compression ratio internal combustion engine, the volume of the combustion chamber or the engine element constituting the combustion chamber of the internal combustion engine or the engine element of the internal combustion engine that is connected to the engine element is driven by driving the control shaft. By changing the stroke volume by the piston, the compression ratio of the internal combustion engine is changed.

  For example, by rotating and driving a control shaft supported by the bearing portion and connected to the cylinder block and the crankcase, the cylinder block and the crankcase are moved relative to each other to change the volume of the combustion chamber, thereby Change the compression ratio of the internal combustion engine. Also, the stroke volume by the piston is changed by driving an eccentric control shaft connected to the crank pin or the piston pin, thereby changing the compression ratio of the internal combustion engine.

  Therefore, the change of the compression ratio of the internal combustion engine, for example, the change of the compression ratio by the relative movement of the cylinder block and the crankcase is performed by rotationally driving the control shaft, and the control shaft, the bearing portion and other contact portions ( Hereinafter, there will be a sliding portion between the control shaft and the like. Therefore, by supplying lubricating oil to the sliding portion by the lubricating oil supply means, it is possible to suppress wear of the control shaft and the like at the sliding portion.

  Here, when the control shaft is rotationally driven to change the compression ratio of the internal combustion engine, lubricating oil is supplied to the control shaft and the like, but particularly immediately before the control shaft is rotationally driven or at the start of the rotational drive. Increases the amount of lubricating oil supplied to the control shaft or the like compared to when the control shaft is not rotationally driven. Then, by increasing the supply amount of the lubricating oil in the predetermined period, sufficient lubricating oil is supplied to the control shaft and the like, and the static friction force on the control shaft and the like is reduced.

Further, when the control shaft is driven to rotate after the predetermined period has elapsed, since the control shaft is in a hydrodynamic bearing state, lubricating oil is interposed between the contact portion of the control shaft and the like, and the control shaft is controlled. Wear of the shaft and the like is ensured more reliably. In addition, it becomes possible to reduce the load of the internal combustion engine due to the supply of the lubricating oil by limiting the time during which the lubricating oil is supplied in an increased amount to the predetermined period. Further, in order to reduce the load on the internal combustion engine, when the control shaft is not rotationally driven, that is, when the compression ratio of the internal combustion engine is constant, the supply amount of lubricating oil to the control shaft or the like is made as small as possible. Is preferred.

  When the control shaft is still rotationally driven after the predetermined period has elapsed, that is, when the compression ratio of the internal combustion engine is being changed, the amount of lubricating oil supplied by the lubricating oil supply means is reduced. You may make it lose weight. As described above, when the control shaft is rotationally driven after the lapse of the predetermined period, the control shaft is in a hydrodynamic bearing state, so even if the amount of supplied lubricating oil is reduced, the control shaft or the like is worn. Is less likely to become noticeable. On the other hand, it is possible to reduce the load on the variable compression ratio internal combustion engine for supplying the lubricating oil by the lubricating oil supply means. It should be noted that the amount of lubricating oil supplied to the control shaft or the like is preferably reduced to an amount close to the amount of lubricating oil supplied when the control shaft is stopped as long as the control shaft or the like is not significantly worn. In addition, about the reduction | decrease in the amount of lubricating oil supplied, you may make it reduce the amount of lubricating oil gradually or in steps.

  Further, in the above-described variable compression ratio internal combustion engine, a lubricating oil pressure detection for detecting a pressure of the lubricating oil in the lubricating oil supply means or a lubricating oil pressure in a lubricating oil supply passage connected to the lubricating oil supply means. Means are further provided. When the pressure detected by the lubricating oil pressure detecting means is lower than a predetermined pressure, the compression ratio control means prohibits the change of the compression ratio of the internal combustion engine.

  The factor that lowers the pressure of the lubricating oil, that is, the hydraulic pressure in the above-mentioned part is that a sufficient amount of lubricating oil is not ensured. Accordingly, it becomes difficult to reliably supply the lubricating oil to the control shaft and the like, in particular, to increase the amount of the lubricating oil immediately before the rotational driving of the control shaft described above or in a predetermined period from the start of the rotational driving. In such a case, if the control shaft is driven to rotate to change the compression ratio of the internal combustion engine, wear of the control shaft or the like may become remarkable, or seizure may occur. Therefore, in such a case, it is prohibited to rotate the control shaft to change the compression ratio of the internal combustion engine.

  Here, in the internal combustion engine, there is a case where the lubricating oil having the same part of the supply path as the above-described lubricating oil is used for purposes other than the supply to the control shaft or the like. However, since there is an upper limit on the total amount of lubricating oil, it may be difficult to secure a sufficient amount of lubricating oil when supplying the lubricating oil to the control shaft. Therefore, in the above-described variable compression ratio internal combustion engine, the lubricating oil supplied to the control shaft or the bearing portion by the lubricating oil supply means is supplied with lubricating oil having the same part of the supply path. When the engine element is further provided, based on the operating state of the internal combustion engine, supply of the lubricant oil to the control shaft or the bearing portion by the lubricant oil supply means, and supply of the lubricant oil to the engine element of the internal combustion engine Which of these is prioritized is determined.

  Accordingly, when it is determined that priority should be given to changing the compression ratio of the internal combustion engine based on the operating state of the internal combustion engine, for example, it is necessary to immediately improve the emission from the internal combustion engine by changing the compression ratio. If it is determined that there is, first, the lubricating oil is preferentially supplied to the control shaft or the like. On the other hand, when it is judged that the engine element of the internal combustion engine to which the lubricating oil is supplied and the operation of the engine element should be prioritized over the change of the compression ratio of the internal combustion engine, the lubricating oil to the control shaft etc. The lubricating oil is supplied to the engine element. In this case, in order to prevent wear of the control shaft or the like, the change of the compression ratio of the internal combustion engine is set in a standby state, and after the supply of the lubricating oil to the engine element is finished, the supply of the lubricating oil to the control shaft or the like is not performed. It is preferable to start and change the compression ratio of the internal combustion engine.

  By doing in this way, it becomes possible to supply lubricating oil to the elements more suitable among the engine elements including the control shaft etc. in the operating state of the internal combustion engine at that time, and the operating state of the internal combustion engine can be reduced. It becomes possible to keep the state as good as possible.

  In particular, when the engine element of the internal combustion engine is intake / exhaust valve control means for changing the opening / closing characteristics of at least one of the intake valve or the exhaust valve of the internal combustion engine by the supplied lubricating oil, that is, so-called variable motion. In the case of the valve mechanism, the supply of the lubricating oil to the intake / exhaust valve control means has priority over the supply of the lubricating oil to the control shaft or the bearing portion by the lubricating oil supply means based on the operating state of the internal combustion engine. It is preferable to do so.

  When the opening / closing characteristics of the intake valve or the exhaust valve are changed by the intake / exhaust valve control means, the influence on the combustion state in the internal combustion engine, in particular, on the stability of the combustion is large. In other words, when lubricating oil is supplied to the intake / exhaust valve control means and the means operates, it can be said that there is a high need to bring the combustion state of the internal combustion engine to the target state. Therefore, in such a case, the supply of lubricating oil to the intake / exhaust valve control means is given priority over the supply of lubricating oil to the control shaft, etc., so that the combustion stability of the internal combustion engine can be ensured more reliably. It becomes possible to do.

  In an internal combustion engine in which the compression ratio is changed by being driven by a rotationally driven control shaft, the engine element of the internal combustion engine is appropriately supplied with lubricating oil to the control shaft and the contact portion thereof. It is possible to suppress wear on the sliding portion and reduce the load on the internal combustion engine due to the supply of lubricating oil.

  Here, an embodiment of a variable compression ratio internal combustion engine according to the present invention will be described based on the drawings.

  FIG. 1 is a diagram illustrating a configuration of a mechanism that allows a compression ratio to be changed in a variable compression ratio internal combustion engine 1 in which the compression ratio can be changed, and FIG. 2 illustrates a change in the compression ratio in the variable compression ratio internal combustion engine 1. It is a figure which shows roughly the transition performed. The variable compression ratio internal combustion engine 1 changes the compression ratio by moving a cylinder block 3 having a cylinder 2 in the axial direction of the cylinder 2 with respect to a crankcase 4 to which a piston 15 shown in FIG. Is an institution.

  As shown in FIG. 1, a plurality of raised portions are formed at lower portions on both sides of the cylinder block 3, and a cam storage hole 5 is formed in each raised portion. The cam storage hole 5 has a circular shape and is formed so as to be perpendicular to the axial direction of the cylinder 2 and parallel to the arrangement direction of the plurality of cylinders 2. The plurality of cam housing holes 5 on one side are all located on the same axis. The pair of axes of the cam storage holes 5 on both sides of the cylinder block 3 are parallel.

  The crankcase 4 is formed with a standing wall portion so as to be positioned between the plurality of raised portions in which the cam housing holes 5 described above are formed. A semicircular recess is formed on the surface of each standing wall portion facing the outside of the crankcase 4. Moreover, the cap 7 attached with the volt | bolt 6 is prepared for each standing wall part, and the cap 7 also has a semicircle recessed part. Moreover, when the cap 7 is attached to each standing wall portion, a circular bearing housing hole 8 is formed. The shape of the bearing storage hole 8 is the same as that of the cam storage hole 5 described above.

  Similar to the cam housing hole 5, the plurality of bearing housing holes 8 are perpendicular to the axial direction of the cylinder 2 when the cylinder block 3 is attached to the crankcase 4 and parallel to the arrangement direction of the plurality of cylinders 2. Each is formed to be. The plurality of bearing housing holes 8 are also formed on both sides of the cylinder block 3, and the plurality of bearing housing holes 8 on one side are all located on the same axis. The pair of axes of the bearing housing holes 8 on both sides of the cylinder block 3 are parallel. Further, the distance between the cam housing holes 5 on both sides and the distance between the bearing housing holes 8 on both sides are the same.

  Control shafts 9 are inserted through the two rows of cam storage holes 5 and bearing storage holes 8 that are alternately arranged. As shown in FIG. 1, the control shaft 9 includes a shaft portion 9a and a cam portion 9b having a right circular cam profile fixed to the shaft portion 9a while being eccentric with respect to the central axis of the shaft portion 9a. The movable bearing portions 9c having the same outer shape as the cam portions 9b and rotatably attached to the shaft portions 9a are alternately arranged. The movable bearing portion 9c is provided with a shaft housing hole 9e, and the movable bearing portion 9c rotates with respect to the shaft portion 9a by adopting a configuration in which the shaft portion 9a of the control shaft 9 is inserted. It is possible to move. The pair of control shafts 9 have a mirror image relationship. Further, an attachment portion 9d for a worm wheel 10 to be described later is formed at the end of the control shaft 9. The center axis of the shaft portion 9a and the center of the attachment portion 9d are eccentric, and the center of the cam portion 9b and the center of the attachment portion 9d coincide.

  The movable bearing portion 9c is also eccentric with respect to the shaft portion 9a, and the amount of eccentricity is the same as that of the cam portion 9b. In each control shaft 9, the eccentric directions of the plurality of cam portions 9b are the same. Further, since the outer shape of the movable bearing portion 9c is the same circle as the cam portion 9b, the outer surface of the plurality of cam portions 9b and the outer surface of the plurality of movable bearing portions 9c are rotated by rotating the movable bearing portion 9c. Can be matched.

  A worm wheel 10 is attached to one end of the shaft portion 9 a of each control shaft 9. Worm gears 11a and 11b are engaged with the pair of worm wheels 10 fixed to the ends of the pair of control shafts 9, respectively. The worm gears 11 a and 11 b are attached to one output shaft of the motor 12. The worm gears 11a and 11b have spiral grooves that rotate in opposite directions. For this reason, when the motor 12 is rotated, the pair of control shafts 9 rotate in the reverse direction via the worm wheel 10. The motor 12 is fixed to the cylinder block 3 and moves integrally with the cylinder block 3.

  Next, a method for controlling the compression ratio in the variable compression ratio internal combustion engine 1 having the above-described configuration will be described in detail. 2 (a) to 2 (c) are sectional views showing the relationship between the cylinder block 3, the crankcase 4, and the control shaft 9 constructed between them. 2A to 2C, the central axis of the shaft portion 9a is indicated by a, the center of the cam portion 9b is indicated by b, and the center of the movable bearing portion 9c is indicated by c. FIG. 2A shows a state in which the outer peripheries of all the cam portions 9b and the movable bearing portion 9c coincide with each other when viewed from the extension line of the shaft portion 9a. At this time, the pair of shaft portions 9 a are located outside the cam housing hole 5 and the bearing housing hole 8 here.

  When the motor 12 is driven from the state of FIG. 2A and rotated in the direction of the arrow of the shaft portion 9a, the state of FIG. 2B is obtained. At this time, since the cam portion 9b and the movable bearing portion 9c are displaced in the eccentric direction with respect to the shaft portion 9a, the cylinder block 3 can be slid to the top dead center side with respect to the crankcase 4. The sliding amount is maximized when the control shaft 9 is rotated until the state shown in FIG. 2C is reached, and is twice the eccentric amount of the cam portion 9b and the movable bearing portion 9c. The cam portion 9b and the movable bearing portion 9c rotate inside the cam housing hole 5 and the bearing housing hole 8, respectively, and allow the position of the shaft portion 9a to move inside the cam housing hole 5 and the bearing housing hole 8, respectively. is doing.

  By using the mechanism as described above, the cylinder block 3 can be moved relative to the crankcase 4 in the axial direction of the cylinder 2. As a result, the cylinder block 3 and the cylinder head 13 shown in FIG. The relative position is changed so that the compression ratio can be variably controlled.

FIG. 3 shows a schematic configuration of the variable compression ratio internal combustion engine 1 including the mechanism for changing the compression ratio shown in FIG. An intake pipe 18 is connected to the cylinder 2, and intake air is sent into the cylinder 2 via the intake port. The intake air flows into the cylinder 2 by opening and closing the intake valve 16. An exhaust pipe 19 is connected to the variable compression ratio internal combustion engine 1, and exhaust in the cylinder 2 is discharged via an exhaust port. Exhaust of the exhaust to the outside of the cylinder 2 is performed by opening and closing the exhaust valve 17. Further, a fuel injection valve 38 is provided at the intake port, and a spark plug 37 is provided at the top of the cylinder 2.

  In addition, variable valve mechanisms that change the open / close characteristics of the intake valve 16 and the exhaust valve 17 are provided as an intake side variable valve mechanism 14a and an exhaust side variable valve mechanism 14b, respectively. Each variable valve mechanism is supplied with lubricating oil, so that the phase of the cam that determines the opening / closing characteristics of the intake valve 16 and the exhaust valve 17 with respect to the crankshaft of the variable compression ratio internal combustion engine 1 is changed. The opening / closing characteristics of the valve 16 and the exhaust valve 17 are changed.

  Here, the lubricating oil supply path in the variable compression ratio internal combustion engine 1 will be described. Lubricating oil 21 is stored in an oil pan 20 provided at the lower portion of the crankcase 4. The stored lubricating oil 21 is pumped to each part of the variable compression ratio internal combustion engine 1 by a pump 23. The pump 23 is connected to the crankshaft of the variable compression ratio internal combustion engine 1 and is a pump that pumps lubricating oil using the engine output of the variable compression ratio internal combustion engine 1 as a power source.

  The lubricating oil pumped by the pump 23 is first sent to the filter 24 through the lubricating oil supply pipe 26, and is then sent to the lubricating oil supply main pipe 30 after removing impurities contained in the lubricating oil. An oil hole supply branch pipe 27 is connected to the lubricating oil supply main pipe 30, and part of the lubricating oil pressure-fed to the lubricating oil supply main pipe 30 is sent to the oil hole 32, from the oil hole 32. It is supplied to a sliding part such as a bearing portion of the crankshaft.

Further, the lubricating oil supply main pipe 30, the shaft portion 9a constituting the control shaft 9 previously described, the cam portion 9b, the movable bearing portions 9c, and the cam housing holes 5 and the movable shaft receiving portion 9c which houses the cam portion 9b A variable compression ratio mechanism supply branch pipe 28 for supplying lubricating oil is connected to the bearing housing hole 8 (hereinafter referred to as “variable compression ratio mechanism related part”) to be stored, and the lubricating oil is supplied to each part. Further, the supply amount of the lubricating oil through the variable compression ratio mechanism supply branch pipe 28 is controlled by the opening degree of the flow rate adjustment valve 33. Further, a bypass branch pipe 34 that is provided in parallel to the flow rate adjustment valve 33 and that bypasses the flow rate adjustment valve 33 and supplies lubricating oil is provided. Therefore, at least the lubricating oil that has passed through the bypass branch pipe 34 is supplied to the variable compression ratio mechanism related part regardless of the opening degree of the flow rate adjustment valve 33. In FIG. 3, only the lubricating oil supply path to the variable compression ratio mechanism-related part on one side is shown, and the description of the lubricating oil supply path to the remaining variable compression ratio mechanism-related part (worm gear 11a side) is omitted. To do.

  Further, the supply branch pipe 29 for variable valve mechanism for supplying lubricant to the intake side variable valve mechanism 14a and the exhaust side variable valve mechanism 14b described above is connected to the lubricant supply main pipe 30. Lubricating oil is supplied to the variable valve mechanism, and the opening / closing characteristics of the intake valve 16 and the exhaust valve 17 are changed. The supply amount of the lubricating oil through the variable valve mechanism supply branch pipe 29 is controlled by the opening degree of the flow rate adjustment valve 35.

  The variable compression ratio internal combustion engine 1 is also provided with an electronic control unit (hereinafter referred to as “ECU”) 31 for controlling the variable compression ratio internal combustion engine 1. The ECU 31 includes a CPU, a ROM, a RAM, and the like for storing various programs and maps to be described later, and the variable compression ratio internal combustion engine 1 according to the operating conditions of the variable compression ratio internal combustion engine 1 and the driver's request. It is a unit that controls the operating state of the.

The ECU 31 includes various sensors for detecting the operating state of the variable compression ratio internal combustion engine 1 such as a crank position sensor 22 and an accelerator opening sensor 36, and a hydraulic pressure for detecting the hydraulic pressure by the lubricating oil flowing through the oil hole supply branch pipe 27. Sensors 25 are connected via electrical wiring, and their output signals are input to the ECU 31. On the other hand, the motor 12 according to the present embodiment is connected to the ECU 31 via an electrical wiring, and the motor 12 is rotated by a command from the ECU 31 to change the compression ratio of the variable compression ratio internal combustion engine 1. . Further, the flow rate adjusting valve 33 and the flow rate adjusting valve 35 are connected via an electric wiring, and the opening degree thereof is adjusted by a command from the ECU 31, so that the variable compression ratio mechanism supply branch pipe 28 and the variable valve mechanism supply The amount of lubricating oil flowing through the branch pipe 29 is adjusted.

  In the variable compression ratio internal combustion engine 1 configured as described above, when the control shaft 9 is rotationally driven by the motor 12 and the compression ratio is changed, the elements are in a sliding state in the variable compression ratio mechanism related part. Therefore, it is indispensable to supply lubricating oil when the control shaft 9 is rotationally driven in order to suppress wear and seizure of the elements. On the other hand, when the supply amount of the lubricating oil increases, the work amount of the pump 23 increases, and as a result, the load of the variable compression ratio internal combustion engine 1 increases. Accordingly, in the variable compression ratio internal combustion engine 1, an appropriate lubricating oil is supplied for suppressing wear and seizure of the variable compression ratio mechanism-related part when changing the compression ratio, and the engine of the variable compression ratio internal combustion engine 1. Lubricating oil supply control for suppressing the increase in load as much as possible will be described based on the flowchart shown in FIG.

  First, in S101, it is determined whether or not the operating state of the variable compression ratio internal combustion engine 1 is a state where a change in the compression ratio is required. Specifically, from the fluctuation of the engine speed calculated from the detection signal from the crank position sensor 22 and the engine load calculated from the detection signal from the accelerator opening sensor 36, the fuel in the variable compression ratio internal combustion engine 1 is determined. In order to make the combustion condition more appropriate, it is determined whether or not the compression ratio needs to be changed. If it is determined in S101 that the operating state of the variable compression ratio internal combustion engine 1 is a state in which a change in the compression ratio is required, the process proceeds to S102. When it is determined that the operating state of the variable compression ratio internal combustion engine 1 is not a state where a change in the compression ratio is required, the present control is terminated.

  In S102, whether or not the intake side variable valve mechanism 14a and the exhaust side variable valve mechanism 14b are operating, that is, the flow rate adjustment valve 35 is opened, and lubricating oil is supplied to each variable valve mechanism. It is determined whether or not it is supplied. If it is determined that both variable valve mechanisms are not operating, the process proceeds to S103, and if both variable valve mechanisms are operating, the process of S102 is repeated until the operations of both variable valve mechanisms are stopped. It is.

  In S103, the opening amount of the flow rate adjustment valve 33 is set to the maximum opening amount in the closed state, and the amount of lubricating oil supplied to the variable compression ratio mechanism related part is changed to the amount of lubricating oil supplied when the control shaft 9 is stopped, that is, the flow rate adjustment. Increase the amount of lubricant supplied when the valve 33 is closed. When the process of S103 ends, the process proceeds to S104.

  In S104, the timer Tr is started. When the process of S104 ends, the process proceeds to S105. In S105, it is determined whether or not the timer Tr has passed a predetermined time T0. If it is determined that the timer Tr has passed the predetermined time T0, the process proceeds to S106. If the timer Tr has not passed the predetermined time T0, the process of S105 is repeated until the predetermined time T0 has passed.

  In S106, by driving the motor 12, the control shaft 9 is rotationally driven, and the change of the compression ratio of the variable compression ratio internal combustion engine 1 is started. When the process of S106 ends, the process proceeds to S107.

In S107, the opening degree of the flow rate adjustment valve 33 that is in the maximum opening state in S103 is reduced, and the amount of lubricating oil supplied to the variable compression ratio mechanism related part is reduced. When the process of S107 ends, the process proceeds to S108.

  In S108, in order to change the compression ratio of the variable compression ratio internal combustion engine 1 to the target compression ratio, it is determined whether or not the rotational movement of the control shaft 9 to the predetermined position where the control shaft 9 should be rotationally moved is completed. Is done. If it is determined that the rotational movement of the control shaft 9 has been completed, the process proceeds to S109. If it is determined that the rotational movement of the control shaft 9 has not been completed, the processing from S106 is repeated again.

  In S109, the opening degree of the flow rate adjustment valve 33 is closed, and this control is finished. Therefore, when the rotational drive of the control shaft 9 is completed, the lubricating oil supplied to the variable compression ratio related mechanism part is only the lubricating oil flowing through the bypass branch pipe 34.

  According to this control, in order to change the compression ratio of the variable compression ratio internal combustion engine 1 by the processing from S103 to S106, before the control shaft 9 is rotationally driven by the motor 12, the flow rate adjustment valve 33 is switched during the period T0. The opening degree becomes the maximum opening degree, and the amount of lubricating oil supplied to the variable compression ratio mechanism related part becomes the maximum amount. After the control shaft 9 is driven to rotate, the amount of lubricating oil supplied to the variable compression ratio mechanism-related part is reduced by the process of S107.

  Therefore, when the control shaft 9 starts to rotate, a sufficient amount of lubricating oil is supplied to the variable compression ratio mechanism-related part, so that the static friction force is reduced and the variable compression ratio mechanism-related part wears. It is suppressed. Further, when the rotation of the control shaft 9 is started, the control shaft 9 is in a hydrodynamic bearing state. Therefore, even if the amount of lubricating oil supplied to the variable compression ratio mechanism related part is reduced, variable compression is performed. Wear in specific mechanism related parts is not likely to be significant. Therefore, during the period T0, the amount of lubricating oil is supplied to such an extent that the static friction at the variable compression ratio mechanism-related part at the start of the rotational drive of the control shaft 9 is reduced, and that the control shaft 9 is in a state of being hydrodynamically bearing. It is a period to get.

  As a result, the amount of lubricating oil to be supplied to the variable compression ratio mechanism-related part is reduced as much as possible while suppressing the wear of the variable compression ratio mechanism-related part. Thus, the engine load of the variable compression ratio internal combustion engine 1 can be reduced. In addition, as a mode of reducing the amount of lubricating oil supplied to the variable compression ratio mechanism-related part performed in S107, the fluid pressure bearing state is achieved by gradually reducing the amount of lubricating oil with the elapsed time or by gradually reducing the amount. A mode in which the amount of the control shaft 9 or the like that is worn is reduced to an amount that does not become noticeable is given. Further, in the range where the wear of the control shaft 9 and the like in the hydrodynamic bearing state is not significant, the flow rate adjustment valve 33 is completely closed and supplied after the rotation of the control shaft 9 as in the process of S109. The lubricating oil may be only the lubricating oil flowing through the bypass branch pipe 34. In other words, it is only necessary to determine how to reduce the amount of the supplied lubricating oil in consideration of the wear of the variable compression ratio mechanism related part.

  Even when there is a request to change the compression ratio of the variable compression ratio internal combustion engine 1, if the intake side variable valve mechanism 14a and the exhaust side variable valve mechanism 14b are in operation, the variable valve ratio is controlled. The rotation of the control shaft 9 is not performed until the operation of the mechanism is stopped. That is, a change in the opening / closing characteristics of the intake / exhaust valve due to the operation of the variable valve mechanism greatly affects the engine output and emission of the variable compression ratio internal combustion engine 1. Therefore, when the variable valve mechanism is in operation, Prioritizing the change in the open / close characteristics of the exhaust valve, the change in the compression ratio of the variable compression ratio internal combustion engine 1 enters a standby state, and the compression ratio is changed after the operation of the variable valve mechanism is stopped. By doing so, the limited amount of lubricating oil is efficiently used, the deterioration of engine output and emission of the variable compression ratio internal combustion engine 1 is suppressed as much as possible, and the compression ratio is changed. Is possible. That is, it is possible to keep the operating state of the variable compression ratio internal combustion engine 1 better by changing the part that preferentially supplies the lubricating oil based on the operating state of the variable compression ratio internal combustion engine 1.

In this control, the control shaft 9 is driven to rotate after the period T0 of increase in the amount of lubricating oil supplied to the variable compression ratio mechanism-related part. Rotational driving may be performed. By doing so, the amount of lubricating oil supplied to the control shaft 9 at the start of rotational driving of the control shaft 9 is smaller than that during execution of this control, but the compression ratio of the variable compression ratio internal combustion engine 1 is reduced. Can be changed as soon as possible.

  Further, this control corresponds to supply of lubricating oil in the variable compression ratio internal combustion engine 1 in which the compression ratio is changed by the relative movement of the cylinder block 3 and the crankcase 4 by the rotational drive of the control shaft 9. However, in the internal combustion engine in which the compression volume is changed by moving the piston pin or the crank pin connected to the piston 15 by driving the control shaft to change the stroke volume by the piston 15, lubrication to the control shaft is performed. It is possible to cope with oil supply.

  Here, the design of the lubricating oil supply path in the variable compression ratio internal combustion engine 1 preferably has a more appropriate structure depending on the amount of lubricating oil supplied by the supply destination. An arrangement of the flow rate adjusting valve 33 and the bypass branch pipe 34 for controlling the lubricating oil to the variable compression ratio mechanism related part will be described with reference to FIGS. 5, 6, and 7. FIG. 5 is a diagram schematically showing a lubricating oil supply path in the case where the flow rate adjusting valve 33 is provided in the supply branch pipe 28 for the variable compression ratio mechanism. FIG. 6 is a diagram schematically showing a lubricating oil supply path in the case where the flow adjusting valve 33 is provided in the oil hole supply branch pipe 27. FIG. 7 is a view schematically showing a lubricating oil supply path when the flow rate adjusting valve 33 is provided in the lubricating oil supply main pipe 30. The elements shown in FIGS. 5, 6, and 7 are extracted and changed from a part of the configuration of the variable compression ratio internal combustion engine 1 shown in FIG. 3, and the same reference numerals are used for the same elements. It is attached.

  The mode of the lubricating oil supply path shown in FIG. 5A is the same as the mode of the lubricating oil supply path of the variable compression ratio internal combustion engine 1 shown in FIG. That is, the flow regulating valve 33 and the bypass branch pipe 34 are provided in the variable compression ratio mechanism supply branch pipe 28, and the connecting portion between the variable compression ratio mechanism supply branch pipe 28 and the lubricating oil supply main pipe 30 is an oil hole. It is located on the downstream side of the connecting portion between the supply branch pipe 27 and the lubricating oil supply main pipe 30. In this aspect of the lubricating oil supply path, the amount of lubricating oil supplied to the crankshaft and the like of the variable compression ratio internal combustion engine 1 via the oil hole 32 can be more reliably ensured.

  5B, the flow rate adjustment valve 33 and the bypass branch pipe 34 are provided in the variable compression ratio mechanism supply branch pipe 28, and the variable compression ratio mechanism supply branch pipe 28 The connecting portion with the lubricating oil supply main pipe 30 is located upstream of the connecting portion between the oil hole supply branch pipe 27 and the lubricating oil supply main pipe 30. In this aspect of the lubricating oil supply path, the amount of lubricating oil supplied to the variable compression ratio mechanism-related portion can be more reliably ensured. 5 (a) and 5 (b), when increasing the amount of lubricating oil supplied to the variable compression ratio mechanism-related part, the opening degree of the flow rate adjusting valve 33 is set. Just make it bigger.

  6A, the flow rate adjusting valve 33 and the bypass branch pipe 34 are provided in the oil hole supply branch pipe 27, and the variable compression ratio mechanism supply branch pipe 28 and the lubricating oil are provided. The connecting portion with the supply main pipe 30 is located downstream of the connecting portion between the oil hole supply branch pipe 27 and the lubricating oil supply main pipe 30. In this aspect of the lubricating oil supply path, the amount of lubricating oil supplied to the crankshaft and the like of the variable compression ratio internal combustion engine 1 via the oil hole 32 can be more reliably ensured.

6 (b), the flow rate adjusting valve 33 and the bypass branch pipe 34 are provided in the oil hole supply branch pipe 27, and the variable compression ratio mechanism supply branch pipe 28 and the lubricant oil. A connecting portion with the supply main pipe 30 is located upstream of a connecting portion between the oil hole supply branch pipe 27 and the lubricating oil supply main pipe 30. In this aspect of the lubricating oil supply path, the amount of lubricating oil supplied to the variable compression ratio mechanism-related portion can be more reliably ensured. Note that FIG.
In the aspect of the lubricating oil supply path shown in (a) and (b), when increasing the amount of lubricating oil supplied to the variable compression ratio mechanism-related part, the opening degree of the flow regulating valve 33 can be made smaller. Good.

  7A, the flow rate adjusting valve 33 and the bypass branch pipe 34 are provided in the lubricating oil supply main pipe 30, and the variable compression ratio mechanism supply branch pipe 28 and the lubricating oil supply are provided. The connection part with the main pipe 30 is located on the downstream side of the connection part between the oil hole supply branch pipe 27 and the lubricating oil supply main pipe 30, and each connection part is located on the upstream side of the flow rate adjusting valve 33. . In this aspect of the lubricating oil supply path, the amount of lubricating oil supplied to the crankshaft and the like of the variable compression ratio internal combustion engine 1 via the oil hole 32 can be more reliably ensured.

The mode of the lubricating oil supply path shown in FIG. 7B is that the flow regulating valve 33 and the bypass branch pipe 34 are provided in the lubricating oil supply main pipe 30, and the variable compression ratio mechanism supply branch pipe 28 and the lubricating oil supply are provided. The connecting part with the main pipe 30 is located on the upstream side of the flow rate adjusting valve 33, and the connecting part between the oil hole supply branch pipe 27 and the lubricating oil supply main pipe 30 is located on the downstream side of the flow rate adjusting valve 33. In this aspect of the lubricating oil supply path, the amount of lubricating oil supplied to the variable compression ratio mechanism-related part can be more reliably secured, and the lubricating oil flowing through the oil hole supply branch pipe 27 can be secured. The amount of oil greatly varies depending on the opening degree of the flow rate adjustment valve 33. That is, in accordance with the opening degree of the flow rate control valve 33 is increased, the amount of lubricating oil flowing through the variable compression ratio mechanism for subjected Kyuedakan 28 while decreasing, amount of lubricating oil flowing through the oil hole for supplying branch pipe 27 is increased .

  7 (c), the flow control valve 33 and the bypass branch pipe 34 are provided in the lubricating oil supply main pipe 30, and the variable compression ratio mechanism supply branch pipe 28 and the lubricating oil supply are provided. The connection part with the main pipe 30 is located upstream of the connection part between the oil hole supply branch pipe 27 and the lubricating oil supply main pipe 30, and each connection part is located upstream of the flow rate adjusting valve 33. . In this aspect of the lubricating oil supply path, the amount of lubricating oil supplied to the variable compression ratio mechanism-related portion can be more reliably ensured. 7A, 7B, and 7C, the flow rate adjusting valve 33 is used to increase the amount of lubricating oil supplied to the variable compression ratio mechanism-related portion. What is necessary is just to make the opening degree of smaller.

  In the variable compression ratio internal combustion engine 1, a second embodiment of the lubricating oil supply control for supplying the lubricating oil to the variable compression ratio mechanism related part will be described based on the flowchart shown in FIG. The hardware configuration of the variable compression ratio internal combustion engine 1 is as described above, and the description thereof is omitted. Further, in the flow chart of the lubricating oil supply control shown in FIG. 8, the same processing as that in the lubricating oil supply control shown in FIG.

In this control, when it is determined in S101 that the operating state of the variable compression ratio internal combustion engine 1 is a state where a change in the compression ratio is required, the process proceeds to S201. In S201, it is detected by the oil pressure sensor 25, the hydraulic pressure of the lubricating oil flowing through the Oiruho Le for subjected Kyuedakan 27 whether larger than a predetermined hydraulic pressure P0 is determined. Not Here, if a predetermined pressure P0 is a Oiruho Le for subjected Kyuedakan 27 and the lubricating oil supply main pipe 30, a degree sufficient amount of lubricating oil can be supplied to the variable compression ratio mechanism associated sites is ensured This is a threshold value for determining whether or not.

Accordingly, means that the oil pressure of the lubricating oil flowing through the Oiruho Le for subjected Kyuedakan 27 when it is determined that greater than a predetermined hydraulic pressure P0, and a sufficient amount of lubricating oil is reserved, subsequent S103 variable compression Lubricating oil is supplied to the specific mechanism-related parts. On the other hand, when the hydraulic pressure of the lubricating oil flowing through the Oiruho Le for subjected Kyuedakan 27 is determined to be a predetermined pressure P0 below, it means that a sufficient amount of lubricating oil is not ensured, S103 subsequent This control is terminated without supplying the lubricating oil to the variable compression ratio mechanism related part. Therefore, in this case, the compression ratio of the variable compression ratio internal combustion engine 1 is not changed.

  According to this control, as in the case of the lubricant supply control shown in FIG. 4, the amount of lubricant to be supplied to the variable compression ratio mechanism-related part is reduced as much as possible while suppressing wear of the variable compression ratio mechanism-related part. Therefore, the work amount of the pump 23 can be reduced, and the engine load of the variable compression ratio internal combustion engine 1 can be reduced. Further, when the amount of lubricating oil supplied to the variable compression ratio related part is not sufficiently secured, the compression ratio of the variable compression ratio internal combustion engine 1 is not changed, and thus the variable compression ratio related part is worn or seized. It becomes possible to suppress more reliably.

  In the variable compression ratio internal combustion engine 1, a third embodiment of the lubricating oil supply control for supplying the lubricating oil to the variable compression ratio mechanism related part will be described based on the flowchart shown in FIG. The hardware configuration of the variable compression ratio internal combustion engine 1 is as described above, and the description thereof is omitted. Further, in the flow chart of the lubricating oil supply control shown in FIG. 9, the same processes as those in the lubricating oil supply control shown in FIG.

  In this control, if it is determined in S101 that the operating state of the variable compression ratio internal combustion engine 1 is a state where a change in the compression ratio is required, the process proceeds to S301. In S301, it is determined whether the request for changing the compression ratio is a request for setting the compression ratio of the variable compression ratio internal combustion engine 1 to a lower compression ratio. That is, by setting the compression ratio of the variable compression ratio internal combustion engine 1 to a lower compression ratio, it is determined whether it is necessary to avoid knocking in the variable compression ratio internal combustion engine 1. If the request to change the compression ratio is a request to set the compression ratio of the variable compression ratio internal combustion engine 1 to a lower compression ratio, the process proceeds to S302. When the request to change the compression ratio is not a request to set the compression ratio of the variable compression ratio internal combustion engine 1 to a lower compression ratio, the process proceeds to S304.

  In S302, whether or not the intake side variable valve mechanism 14a and the exhaust side variable valve mechanism 14b are operating, that is, the flow rate adjustment valve 35 is opened, and the lubricating oil is supplied to each variable valve mechanism. It is determined whether or not it is supplied. If it is determined that both variable valve mechanisms are not operating, the process proceeds to S103, and if both variable valve mechanisms are operated, the process proceeds to S303. In S303, the flow rate adjustment valve 35 is closed to temporarily stop the supply of lubricating oil to both variable valve mechanisms, and the operations of both variable valve mechanisms are temporarily stopped. When the process of S303 ends, the process proceeds to S103.

  In S304, it is determined whether the intake side variable valve mechanism 14a and the exhaust side variable valve mechanism 14b are operating. If it is determined that both variable valve mechanisms are not operating, the process proceeds to S103. If both variable valve mechanisms are operating, the process of S304 is repeated until the operations of both variable valve mechanisms are stopped. It is.

  About the process from S103 to S109, the process same as the process in the flowchart of the lubricating oil supply control shown in FIG. 4 is performed. When the process of S109 ends, the process proceeds to S304. In S304, whether or not the intake-side variable valve mechanism 14a and the exhaust-side variable valve mechanism 14b are temporarily stopped, that is, the intake-side variable valve mechanism 14a and the exhaust-side variable valve mechanism 14b are temporarily set by the processing of S303. It is determined whether or not it is stopped. If it is determined that both variable valve mechanisms are in a temporarily stopped state, the process proceeds to S305, in which both variable valve mechanisms in the temporarily stopped state are restarted, and the opening / closing characteristics targeted by the intake valve 16 and the exhaust valve 17 Is in a state indicating. When the process of S305 ends, this control ends. In S304, when it is determined that both variable valve mechanisms are not in the temporarily stopped state, this control is terminated.

According to this control, as in the case of the lubricant supply control shown in FIG. 4, the amount of lubricant to be supplied to the variable compression ratio mechanism-related part is reduced as much as possible while suppressing wear of the variable compression ratio mechanism-related part. Therefore, the work amount of the pump 23 can be reduced, and the engine load of the variable compression ratio internal combustion engine 1 can be reduced.

  Further, even when there is a request to change the compression ratio of the variable compression ratio internal combustion engine 1, if the request is a request to lower the compression ratio, the change in the compression ratio of the variable compression ratio internal combustion engine 1 is absorbed. If the request is made in preference to the change in the opening / closing characteristics of the exhaust valve and the request is to increase the compression ratio, the change in the opening / closing characteristics of the intake / exhaust valve has priority over the change in the compression ratio of the variable compression ratio internal combustion engine 1. Will be done.

  Thereby, the change in the compression ratio is given priority over the change in the opening / closing characteristics of the intake / exhaust valves, so that knocking in the variable compression ratio internal combustion engine 1 can be avoided more reliably. In addition, since the change in the open / close characteristics of the intake / exhaust valve has priority over the change in the compression ratio, the limited amount of lubricating oil can be used efficiently, and the engine output and emission of the variable compression ratio internal combustion engine 1 can be reduced. While suppressing as much as possible, it becomes possible to change the compression ratio. That is, it is possible to keep the operating state of the variable compression ratio internal combustion engine 1 better by changing the portion that preferentially supplies the lubricating oil based on the operating state of the variable compression ratio internal combustion engine 1.

It is a figure which shows the structure of the mechanism which can change a compression ratio in the variable compression ratio internal combustion engine which can change the compression ratio which concerns on embodiment of this invention. It is a figure which shows roughly the transition in which the compression ratio is changed in the variable compression ratio internal combustion engine which concerns on embodiment of this invention. 1 is a diagram showing a schematic configuration of a variable compression ratio internal combustion engine according to an embodiment of the present invention. 4 is a control flowchart showing a lubricant supply control for supplying a lubricant to a mechanism capable of changing a compression ratio in the variable compression ratio internal combustion engine according to the embodiment of the present invention. FIGS. 5 (a) and 5 (b) are diagrams schematically showing a lubricating oil supply path in the variable compression ratio internal combustion engine according to the embodiment of the present invention. 6 (a) and 6 (b) are second diagrams schematically showing a lubricating oil supply path in the variable compression ratio internal combustion engine according to the embodiment of the present invention. FIGS. 7A, 7B, and 7C are third diagrams schematically showing a lubricating oil supply path in the variable compression ratio internal combustion engine according to the embodiment of the present invention. FIG. 6 is a second control flowchart showing a lubricant supply control for supplying the lubricant to a mechanism capable of changing the compression ratio in the variable compression ratio internal combustion engine according to the embodiment of the present invention. FIG. 9 is a third control flowchart showing a lubricant supply control for supplying a lubricant to a mechanism capable of changing the compression ratio in the variable compression ratio internal combustion engine according to the embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Variable compression ratio internal combustion engine 2 ... Cylinder 3 ... Cylinder block 4 ... Crankcase 5 ... Cam accommodation hole 8 ... Bearing accommodation hole 9 ... · Control shaft 9a ··· Shaft portion 9b ··· Cam portion 9c ··· Movable bearing portion 14a · · · Intake side variable valve mechanism 14b · · · Exhaust side variable valve mechanism 16 ··・ ・ Intake valve 17 ・ ・ ・ ・ Exhaust valve 23 ・ ・ ・ ・ Pump 25 ・ ・ ・ ・ Hydraulic sensor 27 ・ ・ ・ ・ Supply branch pipe for oil hole 28 ・ ・ ・ ・ Supply branch pipe for variable compression ratio mechanism 29 ・... Supply branch pipe for variable valve mechanism 30 ... Lubricant supply main pipe 31 ... ECU
32 ... Oil hole 33 ... Flow control valve 34 ... Bypass branch 35 ... Flow control valve

Claims (6)

Compression ratio control means for changing the compression ratio of the internal combustion engine by driving a control shaft supported by the bearing portion and connected to the engine element of the internal combustion engine;
Lubricating oil supply means for supplying lubricating oil to the control shaft or the bearing portion;
Immediately before starting the change of the compression ratio of the internal combustion engine or during a predetermined period from the start of the change, the amount of lubricating oil supplied to the control shaft or the bearing portion by the lubricating oil supply means is determined when the control shaft is stopped. And a lubricating oil supply control means for increasing the lubricating oil supply amount of the variable compression ratio internal combustion engine. The compression ratio control means rotates the control shaft supported by the bearing portion and connected to the cylinder block and the crankcase, thereby moving the cylinder block and the crankcase relative to each other to compress the compression ratio of the internal combustion engine. The variable compression ratio internal combustion engine according to claim 1, wherein: The lubricating oil supply control means is further configured to supply the lubricating oil supplied to the control shaft or the bearing portion by the lubricating oil supply means when the control shaft is driven to rotate after the elapse of the predetermined period. 3. The variable compression ratio internal combustion engine according to claim 1, wherein the amount is reduced. Lubricating oil pressure detection means for detecting the pressure of the lubricating oil in the lubricating oil supply means or the pressure of the lubricating oil in the lubricating oil supply passage connected to the lubricating oil supply means,
4. The change in the compression ratio of the internal combustion engine by the compression ratio control means is prohibited when the pressure detected by the lubricating oil pressure detection means is lower than a predetermined pressure. The variable compression ratio internal combustion engine according to any one of the above. An engine element of the internal combustion engine that is supplied with lubricating oil having the same part of the supply path as the lubricating oil supplied to the control shaft or the bearing portion by the lubricating oil supply means;
Based on the operating state of the internal combustion engine, it is determined whether to give priority to the supply of lubricant to the control shaft or the bearing portion by the lubricant supply means or the supply of lubricant to the engine element of the internal combustion engine. The variable compression ratio internal combustion engine according to any one of claims 1 to 3, wherein the variable compression ratio internal combustion engine is provided. The engine element of the internal combustion engine is an intake / exhaust valve control means for changing an opening / closing characteristic of at least one of an intake valve or an exhaust valve of the internal combustion engine by supplied lubricating oil,
The supply of the lubricating oil to the intake / exhaust valve control means is performed with priority over the supply of the lubricating oil to the control shaft or the bearing portion by the lubricating oil supply means based on the operating state of the internal combustion engine. The variable compression ratio internal combustion engine according to claim 5.

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