JP5045533B2 - Control device for compression ratio changing mechanism of internal combustion engine - Google Patents

Description

  The present invention relates to a control device for a compression ratio changing mechanism of an internal combustion engine.

  Various compression ratio changing mechanisms that can mechanically change the compression ratio of an internal combustion engine have been proposed. For example, in Patent Document 1, a cylinder block and a crankcase are configured to be relatively movable in the axial direction of a cylinder, and torque of a motor is transmitted to the cylinder block via a cam shaft, and the cylinder block is transmitted by the transmitted driving force. A compression ratio changing mechanism is described in which the compression ratio of the internal combustion engine can be mechanically changed by sliding the cylinder with respect to the crankcase and changing the combustion chamber volume. In this compression ratio changing mechanism, the compression ratio can be changed to the high compression ratio side or the low compression ratio side by bringing the cylinder block and the crankcase close to or away from each other.

As a technique related to the compression ratio changing mechanism, Patent Document 2 describes a technique for reducing the size of the mounted motor by imposing a limit on the target compression ratio in changing the compression ratio toward the high compression ratio side.
JP 2003-206871 A JP 2004-339984 A JP 2007-56837 A JP-A-2005-36944

  In the compression ratio changing mechanism having such a configuration, the in-cylinder pressure of the internal combustion engine acts on the compression ratio changing mechanism as a force for separating the cylinder block and the crankcase. Therefore, when the compression ratio is changed to the high compression ratio side where the cylinder block and the crankcase are brought close to each other, the load applied to the motor increases according to the in-cylinder pressure. In particular, under high-load operation or operating conditions where the in-cylinder pressure becomes very high, such as when the compression ratio is high, the load due to the in-cylinder pressure becomes excessive with respect to the driving force of the motor, and the operation of the compression ratio changing mechanism temporarily May stop.

  When the temporarily stopped compression ratio changing mechanism is operated again and accelerated to a predetermined target operating speed, a very large load is applied to the motor. This is because the static friction force is larger than the dynamic friction force, so that a large driving force is required until the stopped compression ratio changing mechanism starts to operate again, and the operation speed of the compression ratio changing mechanism is slow for a while after starting to operate. For this reason, the main factor is that an oil film is hardly formed on a movable part such as a camshaft and the dynamic frictional force is increased.

  If an excessive load is applied to the driving force of the motor when the compression ratio changing mechanism in the stopped state is put into operation again, there is a possibility that the compression ratio changing mechanism cannot be operated in an appropriate operation state. On the other hand, mounting a large motor is considered as a solution, but in this case, problems such as an increase in energy consumption and an increase in cost occur. It is also conceivable to use a gear with a large reduction ratio so that a large torque can be obtained without increasing the size of the motor. However, in this case, the operation speed of the compression ratio changing mechanism is limited. .

The present invention has been made in view of such circumstances, and a compression ratio changing mechanism capable of suppressing an excessive load applied to a driving source that outputs a driving force for operating a compression ratio changing mechanism of an internal combustion engine. An object is to provide a control device.

In order to achieve the above object, a control device for a compression ratio changing mechanism of an internal combustion engine of the present invention comprises:
A driving source;
The internal combustion engine has at least one movable member that operates by a driving force output from the driving source, and changes a combustion chamber volume and / or a piston stroke by the operation of the movable member by the driving force. A compression ratio changing mechanism capable of changing the compression ratio of
Control means for controlling the operation speed of the movable member to a speed not included in a predetermined prohibition speed range when changing the compression ratio of the internal combustion engine to a predetermined target compression ratio by the compression ratio changing mechanism;
It is characterized by providing.

  When the compression ratio changing mechanism changes the compression ratio of the internal combustion engine to the target compression ratio, the operating conditions of the compression ratio changing mechanism (for example, the target compression ratio, the deviation between the target compression ratio and the current compression ratio, and / or Alternatively, the operating speed of the movable member is determined according to the operating conditions of the internal combustion engine), and output control of the driving force of the driving source is performed so that the movable member operates at the determined operating speed. Here, it has been found that depending on the speed at which the movable member is operated, the load applied to the drive source may become excessive in the process of changing the compression ratio.

  Therefore, in the present invention, when the movable member is operated, the operating speed range in which the load applied to the driving source becomes excessive is defined as the “prohibited speed range”, and the compression ratio is changed by the compression ratio changing mechanism. The operation speed included in this prohibited speed range is not used as the operation speed of the movable member. By doing so, it is possible to suppress an excessive load applied to the drive source. Therefore, problems such as an abnormal operation of the movable member due to a load exceeding the performance of the drive source, an increase in the size of the drive source and an increase in the energy consumption of the drive source to prevent such an operation abnormality are avoided. It becomes possible.

  The “prohibited speed range” is defined as a range of operating speed of the movable member such that the load applied to the drive source exceeds a predetermined reference value when the compression ratio changing mechanism changes the compression ratio of the internal combustion engine to the target compression ratio. May be. Here, the “predetermined reference value” is, for example, an upper limit value that can be permitted as a load applied to the drive source from the viewpoint of the performance of the drive source (upper limit value of output driving force, etc.), energy consumption efficiency of the drive source, etc. Can be determined based on By doing this, a load exceeding the performance of the drive source is applied, causing an abnormal operation of the movable member, or energy (electric power, etc.) consumed by the drive source, although not exceeding the performance of the drive source, increases energy efficiency. It can suppress that it falls.

  In the present invention, as a specific control method for preventing the use of the speed included in the prohibited speed range as the operation speed of the movable member, the control means sets the target speed of the operation speed of the movable member according to the target compression ratio. If the target speed is a speed included in the prohibited speed range, the determined target speed is corrected so that it is not included in the prohibited speed range, and the corrected target speed (“corrected target” Speed ”) can be the final control target value of the operating speed of the movable member.

  On the other hand, if the initial target speed determined in accordance with the target compression ratio is a speed that is not included in the prohibited speed range, the final target control of the operating speed of the movable member is used as it is. It is good as a value.

By doing this, even when the moving member is requested to operate at an operating speed within the prohibited speed range according to the target compression ratio, the actual operating speed is controlled to be a speed outside the prohibited speed range. It can suppress suitably that the load concerning a drive source becomes excessive.

  As described above, when the stopped movable member is operated again, a large load is applied to the drive source. This is due to the reason that the static friction force is large and the reason that the dynamic friction force is large in the low-speed operation state immediately after starting to operate from the stop state. That is, when the compression ratio is changed to the target compression ratio by the compression ratio changing mechanism, the load applied to the drive source is increased by operating the movable member at an operation speed that does not temporarily stop the operation of the movable member. It can suppress becoming excessive.

  Therefore, in the present invention, the upper limit value of the prohibited speed range is determined by the load applied to the drive source when the compression ratio is changed to the target compression ratio by the compression ratio changing mechanism when the movable member is operated at the operating speed. It can be determined based on the upper limit value of the operation speed that satisfies the condition that the operation of the movable member may stop.

  By operating the movable member at an operation speed higher than the speed included in the prohibited speed range thus determined, the movable member is not temporarily stopped in the process of changing the compression ratio. Since the operation is always performed, it is possible to suppress an excessive load applied to the drive source.

  In order to keep the movable member operating against the in-cylinder pressure even under operating conditions where the in-cylinder pressure can be very high, such as in a high-load operation state of an internal combustion engine or a high compression ratio, It is required to output a very large driving force. It is often not practical to mount such a high-output drive source because of the scale and cost of the apparatus. Therefore, when changing the compression ratio under operating conditions that can increase the in-cylinder pressure, the movable member is allowed to temporarily stop, and the movable member is operated intermittently to achieve the target compression ratio. There is a case where a compression ratio changing method of changing the compression ratio is adopted. In this case, as described above, when the movable member is returned from the stopped state to the operating state, it is inevitable that the load applied to the drive source increases.

  By the way, the magnitude of the load applied to the drive source when the movable member in the stopped state is brought into the operating state again varies depending on the acceleration of the movable member. That is, when accelerating a movable member in a stopped state to a higher speed operation state, it is necessary to accelerate the movable member with a larger acceleration, and the load applied to the drive source tends to increase as the acceleration increases. Therefore, when the movable member in the stopped state is operated again, an increase in the load applied to the drive source can be suppressed by suppressing the target speed of the movable member to the low speed.

  Therefore, in the present invention, the lower limit value of the prohibited speed range is determined by the load applied to the drive source when the compression ratio is changed to the target compression ratio by the compression ratio changing mechanism when the movable member is operated at the operating speed. The lower limit of the operation speed that satisfies the condition that the load applied to the drive source may be larger than a predetermined reference value when the operation of the movable member may stop and the movable member in the stopped state is operated again at the operation speed. Can be determined based on the value.

  Even if the movable member may be temporarily stopped in the process of changing the compression ratio by operating the movable member at an operation speed lower than the speed included in the prohibited speed range determined in this way, When the movable member is accelerated from the stopped state to the operating state again, it is possible to suppress an excessive load applied to the drive source.

The “reference value” can be determined based on the maximum value of the driving force that can be output from the driving source. In this case, accelerating the stopped movable member to the operating speed within the prohibited speed range means that the performance of the drive source is difficult. Also, the “reference value” may be determined based on the maximum load value that allows the energy consumption of the drive source to be within an allowable range. in this case,
Although it is not impossible in terms of the performance of the drive source to accelerate the stopped movable member to the operating speed within the prohibited speed range, the energy consumed by the drive source at that time exceeds the allowable limit. It means to become. In this case, the “reference value” is determined based on a request for energy saving performance of the apparatus related to the compression ratio changing mechanism.

  In the present invention, the inertia moment increases and the operation speed of the movable member is accelerated when the condition that the operation speed of the movable member is decelerated is satisfied in the course of the path through which the driving force of the drive source is transmitted to the movable member. If the condition to do this is satisfied, a variable inertia flywheel that reduces the moment of inertia may be provided.

  With such a configuration, when the operation speed of the movable member is reduced by a load or the like applied to the drive source, it is difficult to reduce the operation speed of the movable member. Therefore, it is possible to make it difficult for the movable member to temporarily stop operating without increasing the size of the drive source. This means that the upper limit value of the prohibited speed range can be set to a lower speed. Therefore, the prohibited speed range can be narrowed from the high speed side.

  In addition, when the operation speed of the movable member is accelerated by the driving force of the drive source, the operation speed of the movable member can be easily accelerated. Therefore, for example, when accelerating the movable member in a stopped state to operate again, it is possible to accelerate to a higher operating speed with a smaller driving force. This means that the lower limit value of the prohibited speed range can be set to a higher speed. Therefore, the prohibited speed range can be narrowed from the low speed side.

  Thus, in the present invention, by further providing the above-described configuration, the range of the prohibited speed range can be reduced without increasing the size of the drive source, and the degree of freedom in controlling the operation speed of the movable member can be expanded. .

  In the above configuration, the variable inertia flywheel has a mechanical configuration in which the moment of inertia increases when the operation speed of the movable member decreases, and the moment of inertia decreases when the operation speed of the movable member accelerates. May be. In addition, it has a configuration that can change the moment of inertia by external control, performs control to increase the moment of inertia when the operating speed of the movable member decelerates, and decreases the moment of inertia when the operating speed of the movable member accelerates Control may be performed. When the inertia moment of the variable inertia flywheel can be controlled by control from the outside as in the latter case, it is not the case where the operation speed of the movable member is decelerated in response to the deceleration request for the operation speed of the movable member, The moment of inertia may be increased when the operation speed of the movable member is reduced by an external factor such as a load on the drive source.

  According to the present invention, it is possible to provide a control device for a compression ratio changing mechanism capable of suppressing an excessive load applied to a driving source that outputs a driving force for operating a compression ratio changing mechanism of an internal combustion engine.

  The best mode for carrying out the present invention will be exemplarily described in detail below with reference to the drawings. The dimensions, materials, shapes, relative arrangements, and the like of the components described in the present embodiment are not intended to limit the technical scope of the invention to those unless otherwise specified.

First, the schematic configuration of the engine and the compression ratio changing mechanism of the present embodiment will be described with reference to FIGS. FIG. 1 is a perspective view showing a schematic configuration of the engine. FIG. 2 is a schematic exploded perspective view of the engine and the compression ratio changing mechanism according to the present embodiment. FIG. 3 is a sectional view of the engine and the compression ratio changing mechanism.

  An engine 100 shown in FIG. 1 is a four-cylinder engine having four cylinders 102 in a cylinder block 103. A piston 170 (FIG. 3) is slidably inserted into each cylinder 102, and the piston 170 is connected to the crankshaft 115 via a connecting rod 171 (FIG. 3). The crankshaft 115 is disposed inside the crankcase 104.

  The cylinder block 103 and the crankcase 104 are configured to be relatively slidable in the axial direction of the cylinder 102 (the stroke direction of the piston 170) by the driving force of the servo motor 112. The driving force (torque) output from the servo motor 112 is transmitted to the cylinder block 103 and the crankcase 104 via a power transmission mechanism (described later) including the worms 111a and 111b and the worm wheel 110, and the transmitted drive is transmitted. The cylinder block 103 and the crankcase 104 are relatively slid by the force. The drive force transmission mechanism of the servo motor 112 and the slide movement mechanism of the cylinder block 103 and the crankcase 104 will be described with reference to FIG.

  As shown in FIG. 2, the cylinder block 103 includes a plurality of raised portions 130 at the lower portion of the side surface, and each raised portion 130 has a cam housing hole 105. The cam housing holes 105 have a circular cross section, and are arranged on the same axis line so as to be perpendicular to the axial direction of the cylinders 102 and parallel to the arrangement direction of the plurality of cylinders 102. The arrangement of the raised portion 130 and the cam storage hole 105 having such a configuration is formed at the lower part of both side surfaces of the cylinder block 103. A pair of axes on which the raised portions 130 and the cam housing holes 105 are formed on both sides are parallel to each other.

  In the crankcase 104, a standing wall portion 132 is formed so as to be positioned between the plurality of raised portions 130 in which the cam housing holes 105 are formed. A concave portion having a semicircular cross section is formed on the surface of each standing wall portion 132 facing the outside of the crankcase 104. Each standing wall 132 is provided with a cap 107 to be attached by a bolt 106, and the cap 107 has a concave semicircular recess. When the cap 107 is attached to each standing wall 132, the bearing housing hole 108 having a circular cross section is formed by both members. The shape of the bearing accommodation hole 108 is the same as that of the cam accommodation hole 105 described above.

  Similar to the cam housing hole 105, the plurality of bearing housing holes 108 are perpendicular to the axial direction of the cylinder 102 and parallel to the arrangement direction of the plurality of cylinders 102 when the cylinder block 103 is attached to the crankcase 104. become. The plurality of bearing housing holes 108 are also formed on both sides of the cylinder block 103, and the plurality of bearing housing holes 108 on one side are all located on the same axis. The pair of axes of the bearing housing holes 108 on both sides of the cylinder block 103 are parallel. The distance between the cam housing holes 105 on both sides and the distance between the bearing housing holes 108 on both sides are the same.

Cam shafts 109 are respectively inserted into the two rows of cam storage holes 105 and bearing storage holes 108 that are alternately arranged. As shown in FIG. 2, the cam shaft 109 has a cam portion 109b and a movable bearing portion 109c on a shaft portion 109a. The cam portion 109b is fixed to the shaft portion 109a while being eccentric with respect to the central axis of the shaft portion 109a, and has a regular circular cam profile. The movable bearing portion 109c has the same outer shape as the cam portion 109b and is rotatably attached to the shaft portion 109a. In the present embodiment, the cam portions 109b and the movable bearing portions 109c are alternately arranged. The pair of cam shafts 109 have a mirror image relationship with the cylinder 102 interposed therebetween. A mounting portion 109d of a worm wheel 110, which will be described later, is formed at the end of the cam shaft 109. The center axis of the shaft portion 109a and the center of the mounting portion 109d are eccentric, and the center of all the cam portions 109b and the center of the mounting portion 109d coincide.

  The movable bearing portion 109c is also eccentric with respect to the shaft portion 109a, and the amount of eccentricity is the same as that of the cam portion 109b. In order to actually construct the camshaft 109, the camshaft 109 is manufactured in a state in which one end of the cam portion 109b is integrally connected in advance, and the movable bearing portion 109c, the other cam portion 109b, Are inserted alternately. Only the cam portion 109b is fixed to the shaft portion 109a with a screw or the like as shown. In this case, the cam portion may be fixed by other methods such as press-fitting or welding. The number of cam portions 109b on the shaft portion 109a matches the number of cam housing holes 105 on one side of the cylinder block 103. Further, the thickness of the cam portion 109b also matches the length of each corresponding cam storage hole 105. Similarly, the number of movable bearing portions 109c on the shaft portion 109a matches the number of bearing housing holes 108 formed on one side of the crankcase 104. Further, the thickness of the movable bearing portion 109c also matches the length of the corresponding bearing housing hole 108.

  In each cam shaft 109, the eccentric directions of the plurality of cam portions 109b are the same. In addition, since the outer shape of the movable bearing portion 109c is the same circle as the cam portion 109b, the outer surface of the plurality of cam portions 109b and the outer surface of the plurality of movable bearing portions 109c are rotated by rotating the movable bearing portion 109c. Can be matched. In this state, the cylinder block 103 and the crankcase 104 are combined, and the cam shaft 109 is inserted into a long hole formed by the plurality of cam storage holes 105 and the plurality of bearing storage holes 108 and assembled. Note that the cap 107 may be attached after the camshaft 109 is disposed with respect to the cylinder block 103 and the crankcase 104.

  The cam housing hole 105, the bearing housing hole 108, the cam portion 109b, and the movable bearing portion 109c have the same exact circular shape. The cylinder block 103 is slidable with respect to the crankcase 104, and a member such as a piston ring that secures airtightness between the cylinder inner surface and the piston is arranged on the sliding surface of both the cylinder blocks 103 so as to be airtight. Ensure sex. Note that the sealing may be performed by a method other than the piston ring, for example, a rubber gasket such as an O-ring.

  Each camshaft 109 has a worm wheel 110 at an attachment portion 109d at the end of the shaft portion 109a. The worm wheel 110 is positioned with a key and is bolted to the mounting portion 109d.

  Worms 111a and 111b mesh with each worm wheel 110 corresponding to the pair of cam shafts 109. The worms 111a and 111b are connected to the output shaft of a single servo motor 112 that can rotate forward and backward. The worms 111a and 111b have a butterfly groove that rotates in opposite directions. For this reason, when a rotational driving force is output from the servo motor 112, the pair of cam shafts 109 receives the rotation of the worm wheel 110 and rotates in opposite directions. The servo motor 112 is fixed to the cylinder block 103 or the like and moves integrally with the cylinder block 103.

  FIGS. 3A to 3C are cross-sectional views of the compression ratio changing mechanism including the cylinder block 103, the crankcase 104, and the cam shaft 109 and the like constructed between them. In each figure, the central axis of the shaft portion 109a in the cam shaft 109 is denoted by reference symbol A, the center of the cam portion 109b is denoted by B, and the center of the movable bearing portion 109c is denoted by C.

FIG. 3A shows a state in which the outer circumferences of all the cam portions 109b and the movable bearing portions 109c coincide with each other when viewed from the extension line of the shaft portion 109a. At this time, the pair of left and right shaft portions 109a are located outside the cam housing hole 105 and the bearing housing hole 108 here. The camshaft angle is defined as zero degrees (0 °) when each shaft portion has such a positional relationship.

  In the state of FIG. 3A, the relative distance between the cylinder block 103 and the crankcase 104 and the piston top dead center position is short, so that the combustion chamber volume is small and the compression ratio is high. On the other hand, in the state of FIG. 3C, the distance between the cylinder block 103 and the piston top dead center position becomes long, the combustion chamber volume is large, and the compression ratio is low. That is, when the cylinder block 103 moves from the position of FIG. 3A to the position of FIG. 3C, the relative positional relationship between the cylinder block 103 and the crankcase 104 changes, and the compression ratio of the engine 100 changes. Changes from a high compression ratio to a low compression ratio.

  When the shaft portion 109a (and the cam portion 109b fixed to the shaft portion 109a) rotates in the direction of the arrow X + in the drawing from the state of FIG. 3A, the state of FIG. 3B is obtained. At this time, since the cam portion 109b and the movable bearing portion 109c are displaced in the eccentric direction with respect to the shaft portion 109a, the cylinder block 103 slides toward the top dead center side with respect to the crankcase 104. That is, the crankcase 104 and the cylinder block 103 are relatively moved so as to be separated from each other. The sliding amount is maximum when the camshaft 109 is rotated in the rotation direction of the arrow X + until the state shown in FIG. 3C is reached, which is twice the eccentric amount of the cam portion 109b or the movable bearing portion 109c. Become. The cam portion 109b and the movable bearing portion 109c rotate inside the cam housing hole 105 and the bearing housing hole 108, respectively, and allow the position of the shaft portion 109a to move inside the cam housing hole 105 and the bearing housing hole 108, respectively. is doing.

  Thus, the rotation direction of the servo motor 112 when rotating the cam shaft 109 in the rotation direction of the cam shaft 109 (arrow X + direction in FIG. 3) when changing the compression ratio to the low compression ratio side is the servo motor 112. Is the positive rotation. Further, the positional relationship between the shaft portions shown in FIG. 3C is assumed to be a cam shaft angle + 90 °. Torque output from the servo motor 112 is transmitted as a driving force for sliding the cylinder block 103 away from the crankcase 104 via the cam shaft 109.

  To change the compression ratio of the engine 100 to the high compression ratio side from the state of FIG. 3C to the state of FIG. 3A, the servo motor 112 is rotated in the reverse direction. In this way, the shaft portion 109a, the cam portion 109b, and the movable bearing portion 109c of the cam shaft 109 are driven to rotate in the direction of the arrow X− in the drawing. Thereby, the cylinder block 103 returns to the state of FIG. 3A, and the compression ratio changes from the low compression ratio to the high compression ratio.

  When the compression ratio is changed from the low compression ratio state of FIG. 3C to the high compression ratio state of FIG. 3A, the torque output from the servo motor 112 is transferred to the cylinder via the cam shaft 109. This is transmitted as a driving force for sliding the block 103 in a direction to bring it close to the crankcase 104.

In a state where the cam portion 109b and the movable bearing portion 109c are completely aligned (FIG. 3A), the plurality of movable bearing portions 109c attached to one cam shaft 109 slide the cylinder up and down. There is also a possibility that it will run idle. For this reason, the engine compression ratio changing mechanism of the present embodiment does not cause a state in which the cam portion 109b and the movable bearing portion 109c are completely matched as shown in FIG. For example, when the rotation position of the cam shaft 109 in the state of FIG. 3A is set to 0 ° as a reference (the forward direction is the reverse rotation direction with the pair of cam shafts 109), the rotation position in the state of FIG. Although it is 90 ° in the positive direction along X +, camshaft rotation is realized in the range of 5 ° to 90 ° without using the vicinity of 0 ° (for example, about 5 °) shown in FIG. By doing so, the above-described problems can be solved. Since the actual slide amount of the cylinder block 103 is considered to be several mm, the eccentricity of the cam portion 109b and the movable bearing portion 109c is obtained so that a specified compression ratio range is obtained in the range of 5 ° to 90 °. It is sufficient to determine the amount, and there is no problem in actual design.

  Further, as a configuration of the compression ratio changing mechanism, a configuration in which the cylinder block 103 is slid toward the bottom dead center side with respect to the crankcase 104 can be adopted. In this case, the control range of the cam shaft 109 may be a cam shaft angle of −5 ° to −90 ° (355 ° to 270 °). Further, when the cylinder block 103 is slid to the top dead center side with respect to the crankcase 104, the control range of the cam shaft 109 may be set to 90 ° to 175 ° or the like.

  With the above-described configuration, the cylinder block 103 and the crankcase 104 are slid relative to each other in the axial direction of the cylinder 102 by the driving force output from the servo motor 112, and the combustion chamber volume is changed. A compression ratio changing mechanism capable of changing the ratio mechanically is realized.

  In this embodiment, the compression ratio variable control for changing the compression ratio of the engine 100 to a predetermined target compression ratio is performed by controlling the compression ratio changing mechanism.

  FIG. 4 is a diagram showing a control block diagram for performing the compression ratio variable control of the present embodiment.

  The ECU 160 in FIG. 4 is a computer having a known configuration such as a CPU, ROM, RAM, and input / output interface. The ECU 160 includes a throttle sensor 161, an accelerator opening sensor 162, a crank angle sensor 163, a motor rotation angle sensor 164 that acquires the rotation angle of the servo motor 112, a water temperature sensor 165 that acquires the cooling water temperature of the engine 100, and the combustion of the engine 100 Various sensors such as an in-cylinder pressure sensor 166 that acquires the in-cylinder pressure in the room are connected, and output signals from these various sensors are input to the ECU 160. Various devices such as the servo motor 112 are connected to the ECU 160, and operations of these various devices are controlled by control signals output from the ECU 160.

  The ROM of ECU 160 stores a target compression ratio map in which the target compression ratio is determined according to the engine speed and the engine load, as shown in FIG. The target compression ratio map may be composed of a plurality of maps in which the optimum target compression ratio is determined more finely according to the operating conditions such as the cooling water temperature, the intake air temperature, and the intake pressure in addition to the rotation speed and the load. good. The target compression ratio is determined in advance as a compression ratio that can optimize engine performance such as fuel efficiency, anti-knock performance, emission, drivability, etc. for each rotation speed, load, and other operating conditions, It is mapped.

  ECU 160 acquires the operating conditions of engine 100 and the current actual compression ratio based on detection signals input from various sensors. The current actual compression ratio is obtained by calculating the rotation angle position of the servo motor 112 from the sensor output from the motor rotation angle sensor 164 and calculating the actual compression ratio of the engine 100 based on the calculated rotation angle position. Can be acquired.

  ECU 160 determines the target compression ratio according to the acquired operating condition of engine 100 with reference to the map described above. Further, the target change speed when changing the compression ratio by the compression ratio changing mechanism is obtained according to the deviation between the current compression ratio and the target compression ratio, the target change speed and the slide movement speed of the cylinder block 103, the cam Based on the relationship between the rotation speed of the shaft 109 and the rotation speed of the servo motor 112 and the reduction ratio of the worm wheel 110 and the worm 111, a target value of the rotation speed of the servo motor 112 is calculated. Then, ECU 160 outputs a control signal to servo motor 112 in order to operate servo motor 112 at the calculated target rotational speed.

  Next, the rotational speed control of the servo motor 112 in this embodiment will be described. The rotational speed of the servo motor 112 has a corresponding relationship with the rotational speed of the cam shaft 109 and the sliding movement speed of the cylinder block 103. Therefore, the following discussion is the same when considering the rotation speed of the cam shaft 109 and the slide movement speed of the cylinder block 103 instead of the rotation speed of the servo motor 112. These rotation speeds and slide movement speeds can be conceptually and comprehensively understood as “operation speeds of the compression ratio changing mechanism”, which correspond to “operation speeds of the movable members” in the present invention.

  In the configuration of the compression ratio changing mechanism of the present embodiment, the in-cylinder pressure of the engine 100 acts on the compression ratio changing mechanism as a force in a direction in which the cylinder block 103 and the crankcase 104 are separated. Therefore, when the compression ratio is changed to the high compression ratio side where the cylinder block 103 and the crankcase 104 are brought close to each other, the load applied to the servo motor 112 increases in accordance with the in-cylinder pressure. In particular, under operating conditions where the in-cylinder pressure can be very large, such as during high load operation or when the compression ratio is high, the load due to the in-cylinder pressure is excessive with respect to the driving force of the servo motor 112, and the servo motor 112 operates. It decelerates and sometimes stops temporarily. When the operation of the servo motor 112 is stopped, the rotational movement of the cam shaft 109 and the sliding movement of the cylinder block 103 are also stopped.

  When accelerating the servo motor 112 that has been stopped to the target rotational speed again, a very large load is applied to the servo motor 112. This is because the static frictional force when the movable parts such as the camshaft 109 and the cylinder block 103 transition from the stationary state to the operating state is large, and the operation speed immediately after the movable parts start operating from the stopped state. When it is late, it is difficult to form an oil film for lubrication in the movable part, and this is because the dynamic friction force in the movable part also increases.

  Therefore, in the rotational speed control of the servo motor 112 of the present embodiment, the servo motor 112 is not stopped when the rotational speed of the servo motor 112 is changed to the target compression ratio by the compression ratio changing mechanism. Control the rotation speed. That is, in the process of changing the compression ratio to the target compression ratio, even when the rotation speed of the servo motor 112 is reduced by the load due to the in-cylinder pressure, the rotation speed is high enough that the servo motor 112 does not reach the stop state. Then, the servo motor 112 is operated.

  When the servo motor 112 is operated at the lower limit of such a high rotational speed, that is, at the rotational speed, the load applied to the servo motor 112 when the compression ratio is changed to the target compression ratio by the compression ratio changing mechanism. Hereinafter, the lower limit value of the rotational speed that satisfies the condition that the operation of the servo motor 112 is not stopped by the above will be referred to as “high speed side lower limit speed β”. In this embodiment, the rotational speed of the servo motor 112 is controlled so that the rotational speed of the servo motor 112 does not become slower than the lower limit speed on the high speed side.

  By the way, even under operating conditions where the in-cylinder pressure can be very high, such as when the engine 100 is in a high-load operation state or a high compression ratio, the servo motor 112 continues to rotate against a large load due to the in-cylinder pressure. Therefore, the servo motor 112 is required to output a very large driving force. It is often not practical to mount such a high-power servomotor because of the scale and cost of the apparatus. Therefore, when changing the compression ratio under operating conditions where the in-cylinder pressure can increase, the rotation of the servo motor 112 is temporarily allowed to stop, and the servo motor 112 is operated intermittently. The compression ratio is intermittently changed to reach the target compression ratio. At this time, as described above, it is inevitable that the load applied to the servo motor 112 increases when the servo motor 112 in the stopped state is brought into the operating state again.

  Here, the magnitude of the load applied to the servo motor 112 when the servo motor 112 in the stopped state is set to the operating state again varies depending on the acceleration when the servo motor 112 accelerates from the stopped state to the target rotational speed. That is, when accelerating the stopped servo motor 112 to a higher rotational speed, it is necessary to accelerate the rotation of the servo motor 112 with a larger acceleration. As the acceleration increases, the load applied to the servo motor 112 increases. Tend to be. Therefore, if the target rotational speed of the servo motor 112 when the stopped servo motor 112 is operated again is not excessively high, it is possible to suppress an excessive increase in the load applied to the servo motor 112.

  Therefore, in the rotational speed control of the servo motor 112 of this embodiment, the servo motor 112 is rotated at such a rotational speed that the servo motor 112 may stop in the process of changing the compression ratio to the target compression ratio by the compression ratio changing mechanism. When operating the servo motor 112 in a stopped state, the load applied to the servo motor 112 when accelerating to the rotational speed again is such that the load applied to the servo motor 112 is a predetermined reference value or less. The servo motor 112 is operated.

  Here, the “reference value” is determined based on the maximum value of the driving force that the servo motor 112 can output. The servo motor 112 may be determined on the basis of the maximum load value such that the power consumption of the servo motor 112 is not more than the allowable upper limit.

  When the servo motor 112 is operated at such an upper limit value of the low rotational speed, that is, at the rotational speed, the load applied to the servo motor 112 when the compression ratio is changed to the target compression ratio by the compression ratio changing mechanism. Although the operation of the servo motor 112 may be temporarily stopped due to the above, the load applied to the servo motor 112 when the servo motor 112 in the stopped state is accelerated to the rotational speed again is below a predetermined reference value. Hereinafter, the upper limit value of the rotational speed satisfying the condition is referred to as “low speed side upper limit speed α”. In this embodiment, the rotation speed of the servo motor 112 is controlled so that the rotation speed of the servo motor 112 does not become higher than the lower speed upper limit speed.

  As described above, in the rotational speed control of the servo motor 112 of the present embodiment, control is performed so that the rotational speed N of the servo motor 112 is faster than the low speed side upper limit speed α and not slower than the high speed side lower limit speed β. The range of rotational speed that is faster than the low speed side upper limit speed α and slower than the high speed side lower limit speed β will be referred to as a “forbidden speed range”.

  FIG. 6 shows the rotational speed N of the servo motor 112 and the maximum value T of the load (required torque) applied to the servo motor 112 when the servo motor 112 is operated at the rotational speed to change the compression ratio to the target compression ratio. It is the figure which showed notionally the relationship.

  In a speed range where the rotational speed N of the servo motor 112 is slower than the high speed side lower limit speed β, the operation of the servo motor 112 may temporarily stop when the load due to the in-cylinder pressure increases. In this case, the maximum load T applied to the servo motor 112 when changing the compression ratio to the target compression ratio is the load applied to the servo motor 112 when the servo motor 112 in a stopped state is accelerated to the operating speed N again. .

  As described above, the load applied at the time of reacceleration from the stopped state tends to increase as the acceleration increases and accordingly the operation speed N increases. Therefore, in the speed region slower than the high speed side lower limit speed β, the relationship between the rotational speed N and the maximum load value T has a positive slope as shown by a curve T1 in FIG.

  In this curve T1, the rotational speed corresponding to the point where the maximum load value T coincides with the maximum value Tmax of the driving force that can be output from the servo motor 112 is defined as the low speed side upper limit speed α. In this case, accelerating the stopped servo motor 112 to a rotational speed faster than the low speed side upper limit speed α means that the performance of the servo motor 112 is difficult.

  In the speed region above the high speed side lower limit speed β where the servo motor 112 is not stopped, the increase in friction is small even if the speed is reduced to some extent. Therefore, although the rotation speed of the servo motor 112 is higher than the rotation speed within the prohibited speed range, the maximum value of the load applied to the servo motor 112 is relatively small as indicated by the curve T2.

  In the rotational speed control of the servo motor 112 of the present embodiment, as described above, the target speed of the rotational speed of the servo motor 112 is calculated according to the deviation between the target compression ratio and the current compression ratio, and the calculated target speed is When the speed is included in the prohibited speed range, the target speed is corrected to be accelerated or decelerated to a speed not included in the prohibited speed range, and the corrected speed is used as the final rotational speed control of the servo motor 112. The control target value was determined.

  The execution procedure of the rotational speed control of the servo motor 112 of this embodiment will be described with reference to FIG. FIG. 7 is a flowchart showing a rotation speed control routine of the servo motor 112 of this embodiment. This routine is repeatedly executed at predetermined intervals by the ECU 160 while the engine 100 is operating.

  In step S101, ECU 160 acquires the operating state of engine 100. Specifically, the detection signals input from the various sensors described above are read, the throttle opening, the accelerator opening, the crank angle θ, the rotation angle of the servo motor, the cooling water temperature, the intake air temperature, the intake air pressure, the transmission state, the engine Information such as the rotation speed, the engine required load, and the current compression ratio ε of the engine 100 is calculated and acquired.

In step S102, ECU 160 calculates the target compression ratio epsilon _TRG. That is, the target compression ratio ε _TRG is read from the above-described target compression ratio map according to the engine operating state acquired in step S101.

In step S103, ECU 160 determines whether or not the compression ratio of engine 100 should be changed. That is, it is determined whether or not the target compression ratio ε _TRG calculated in step S102 matches the current compression ratio ε of the engine 100 acquired in step S101. If an affirmative determination is made in this step (determination that the compression ratio should be changed), ECU 160 proceeds to step S104. On the other hand, if a negative determination is made in this step (determination that it is not necessary to change the compression ratio), ECU 160 once exits this routine.

In step S104, the ECU 160 calculates a deviation Δε between the target compression ratio ε _TRG and the current compression ratio ε, and in a subsequent step S105, the ECU 160 calculates a target speed _NTRG of the rotation speed of the servo motor 112 based on the deviation Δε. calculate.

In step S106, ECU 160 determines whether or not the rate at which the target speed _{N TRG} calculated in step S105 is included in the prohibited speed region. In this step, the target speed _{N TRG} is not included in the prohibited speed range _{(N TRG} ≦ alpha, or, β ≦ _{N TRG)} if it is determined that, ECU 160 proceeds to step S107, the rotational speed control of the servo motor 112 The target speed _NTRG is set as the final control target value N _FIN .

On the other hand, in this step, when the target speed _{N TRG} is it is determined inhibited rate is the region of the velocity and _{(α <N TRG <β)} , ECU160 proceeds to step S108, the servo motor 1
As the final control target value N _FIN for the twelve rotational speed control, the low speed side upper limit speed α or the high speed side lower limit speed β is set. Selection of the low-speed side upper limit speed α or the high-speed side lower limit speed β, for example, to select the closer to the current rotational speed of the servo motor 112, selects the closer to the target speed N _TRG, than the reference value a deviation Δε It can be determined by a method such as setting the high speed side lower limit speed β if it is large, and setting the low speed side upper limit speed α if it is small. Other selection methods may be used. Also, it can be set to a speed faster than the high speed side lower limit speed β or a speed slower than the low speed side upper limit speed α.

In step S109, the ECU 160 outputs a control signal corresponding to the final control target value N _FIN set in step S107 or step S108 to the servo motor 112, and once exits this routine.

  By executing the rotational speed control of the servo motor 112 of the present embodiment described above, it is possible to suppress an excessive driving force applied to the servo motor 112, so a large motor is mounted as the servo motor 112. This eliminates the need to reduce the size and cost of the device. Moreover, since it can suppress that the torque demanded to a motor becomes large too much, power consumption can be reduced.

  The prohibited speed range may be a speed range that varies depending on the operating conditions of the engine 100 and the compression ratio change conditions (conditions such as the compression ratio change direction, the target compression ratio, the current compression ratio, etc.). For example, as the engine load becomes higher, the high speed lower limit speed β may be set to a higher speed, and the low speed upper limit speed α may be set to a lower speed. In order to further simplify the control, a certain medium speed rotation speed range may be set as the prohibited speed range regardless of the operating conditions of the engine 100 or the like.

  In addition, there is no prohibited speed range under the operating condition / compression ratio changing condition in which the servo motor 112 does not stop due to a load no matter what rotational speed the servo motor 112 is operated. For example, in the case of changing the compression ratio to the low compression ratio side, the force resulting from the in-cylinder pressure acts to assist the compression ratio change by the compression ratio changing mechanism. It is considered that the operation does not stop. In such a case, since all the rotation speeds possible for the servo motor 112 are speeds equal to or higher than the high speed side lower limit speed β, there is no prohibited speed range.

  Even if the compression ratio is changed to the high compression ratio side, if the in-cylinder pressure does not increase so much, such as in a low-load operation state, the operation of the compression ratio changing mechanism stops even if a load due to the in-cylinder pressure is applied. The case where it does not think is possible. Even in such a case, since all the rotation speeds possible for the servo motor 112 are speeds equal to or higher than the high speed side lower limit speed β, there is no prohibited speed range.

  Even when the compression ratio is changed to the high compression ratio side, and the operation of the compression ratio changing mechanism may stop due to the load due to the in-cylinder pressure, the in-cylinder pressure in the low load operation state or the like Is not so large, there may be a case where the load applied to the servo motor 112 is always equal to or less than the reference value when the compression ratio changing mechanism in the stopped state is operated again. In such a case, since the low speed side upper limit speed α coincides with the high speed side lower limit speed β, there is no prohibited speed range.

Thus, depending on the operating conditions of the engine 100 and the compression ratio changing conditions (conditions such as the compression ratio changing direction, the target compression ratio, the current compression ratio, etc.) by the compression ratio changing mechanism, the prohibited speed range may not exist. When the prohibited speed range does not exist, the target rotational speed _NTRG of the servomotor 112 calculated based on the deviation Δε between the target compression ratio _εTRG and the current compression ratio ε is directly used for the rotational speed control of the servomotor 112. The final control target value N _FIN is used.

  Next, a description will be given of an embodiment in which a mechanical device is added to the compression ratio changing mechanism to suppress an excessive load on the servo motor 112.

  FIG. 8 is an exploded perspective view showing the configuration of the compression ratio changing mechanism of the present embodiment. The same reference numerals and names are used for components that are substantially the same as those in the first embodiment, and detailed description thereof is omitted. As shown in FIG. 8, the compression ratio changing mechanism of the present embodiment includes a variable inertia flywheel 180A that can change the moment of inertia between the servo motor 112 and the worm 111, the worm wheel 110, and the camshaft. 109, a configuration including a variable inertia flywheel 180B capable of changing the moment of inertia, or a configuration including both variable inertia flywheels 180A and 180B.

  These variable inertia flywheels 180A and 180B (hereinafter, when the contents common to both are described, they are simply referred to as “variable inertia flywheel 180”) are servo controlled by the load applied to the servomotor 112. When the condition for reducing the rotational speed of the motor 112 is satisfied, the moment of inertia increases. When the condition for accelerating the rotational speed of the servo motor 112 by the driving force of the servo motor 112 is satisfied, the inertia The moment of inertia changes so that the moment decreases.

  Conditions for reducing the rotational speed of the servo motor 112 due to the load applied to the servo motor 112 include a condition for changing the compression ratio to the high compression ratio side in a high load operation state where the in-cylinder pressure is high and a state where the compression ratio is high, The condition etc. which the rotational speed of the servomotor 112 is low can be illustrated. If the inertia moment of the variable inertia flywheel 180 increases when such a deceleration condition is satisfied, the rotational speed of the servo motor 112 becomes difficult to reduce. That is, the operation of the servo motor 112 is not easily stopped.

  This means that the high speed side lower limit speed β, which is determined based on the lower limit value of the rotational speed at which the servo motor 112 is not stopped by the load applied to the servo motor 112, can be set to a lower speed side. That is, the prohibited speed range can be narrowed from the high speed side.

  As a condition for accelerating the rotation speed of the servo motor 112 by the driving force of the servo motor 112, the servo motor 112 in a stopped state is operated again, or the servo motor 112 immediately after the operation is started is accelerated to a target rotation speed. This is the case. If the inertia moment of the variable inertia flywheel 180 decreases when such an acceleration condition is satisfied, the rotational speed of the servo motor 112 is easily accelerated. That is, it is possible to accelerate to a higher rotational speed with a smaller driving force.

  This means that the low speed side upper limit speed α, which is determined as the upper limit value of the rotational speed so that the load applied to the servo motor 112 does not exceed the reference value when accelerating the stopped servo motor 112 to the rotational speed, This means that it can be set to a higher speed. That is, the prohibited speed range can be narrowed from the low speed side.

  Thus, by providing the variable inertia flywheel 180 according to the present embodiment in the compression ratio changing mechanism, it is possible to more suitably suppress an excessive load applied to the servomotor 112, and to reduce the servo. The range of the forbidden speed range can be reduced without increasing the size of the motor 112, and the degree of freedom in controlling the rotational speed of the servo motor 112 can be expanded.

  In the present embodiment, when the variable inertia flywheel 180A is provided between the servo motor 112 and the worm 111, the torque output from the servo motor 112 can be reduced, so that the servo motor 112 can be reduced in size. Thus, the variable range of the inertia moment of the variable inertia flywheel can be reduced. On the other hand, when the variable inertia flywheel 180B is provided between the worm wheel 110 and the cam shaft 109, the influence of torsion caused by the rigidity of the cam shaft 109 can be reduced. The control accuracy can be improved.

  As the variable inertia flywheel 180 in the present embodiment, those having various known configurations can be used. Preferably, the servo motor 112 and the camshaft 109 have a variable moment of inertia characteristic as described above in both the forward and reverse rotation directions. However, as described above, the variable inertia flywheel 180 of the present embodiment is mainly used. If the servo motor 112 can be hardly decelerated and accelerated in changing the compression ratio to the high compression ratio side, an effect of suppressing the load applied to the servo motor 112 can be achieved. Therefore, at least in the rotation direction of the servo motor 112 and the camshaft 109 when the compression ratio is changed to the high compression ratio side, the inertia moment increases at the time of deceleration and the inertia moment decreases at the time of acceleration. It can be suitably used as the variable inertia flywheel 180 of the present embodiment.

  For example, as shown in FIG. 9, a variable inertia flywheel 180 including a flywheel main body 41 having a constant inertia moment and a variable inertia moment portion 40 having a variable inertia moment can be exemplified. The flywheel body 41 has a disk shape, rotates around the rotation center 46 in the direction of the arrow when changing the compression ratio to the high compression ratio side, and the moment of inertia around the rotation center 46 is constant. is there.

  The variable moment of inertia part 40 is mainly composed of a first moving body 43, a second moving body 44, and a spring 45. Further, the flywheel main body 41 is provided with a groove 42, and in the groove 42, the flywheel main body 41 is arranged so that the distance from the rotation center 46 becomes longer as the flywheel main body 41 is in the rotational direction side. The first moving body 43 and the second moving body 44 are configured to be movable in the groove 42, and the second moving body 44 and the first moving body 43 are arranged along the rotation direction of the flywheel. It is accommodated in the groove 42 in order. A spring 45 is provided between the second moving body 44 and one end opposite to the rotational direction in the groove 42.

  Here, FIG. 9A shows a balance between the weight of the first moving body 43 and the second moving body 44 and the centrifugal force applied to the spring 45 in a state where the flywheel is rotating at a constant speed. It shows the state. Here, when the flywheel performs acceleration, an inertia force in a direction opposite to the rotation direction of the flywheel acts on the first moving body 43 and the second moving body 44. By this inertial force, the first moving body 43 and the second moving body 44 move in the groove 42 in the direction in which the spring 45 is provided against the urging force of the spring 45. The state is shown in FIG.

  As shown in FIG. 9B, when the first moving body 43 and the second moving body 44 move in the groove 42 in the direction in which the spring 45 is provided by acceleration of the flywheel, the moving bodies 43 and 44 are moved. And the rotation center 46 change from L3 to L3 ′ and from L4 to L4 ′, respectively, and become shorter. Therefore, the inertia moment of each moving body 43, 44 around the rotation center 46 is reduced, and as a result, the inertia moment of the flywheel is reduced.

  Conversely, when the flywheel is decelerated in the state of FIG. 9A, inertial force in the same direction as the rotation direction of the flywheel acts on the first moving body 43 and the second moving body 44. Due to this inertial force, the first moving body 43 and the second moving body 44 move in the direction opposite to the direction in which the spring 45 is provided in the groove 42 against the biasing force of the spring 45. The state is shown in FIG.

  As shown in FIG. 9C, when the first moving body 43 and the second moving body 44 move in the groove 42 in the direction opposite to the direction in which the spring 45 is provided by the deceleration of the flywheel, each movement The distances between the bodies 43 and 44 and the rotation center 46 change from L3 to L3 ″ and L4 to L4 ″, respectively, and become longer. Therefore, the inertia moment of each moving body 43, 44 around the rotation center 46 increases, and as a result, the inertia moment of the flywheel increases.

  When the acceleration or deceleration state of the flywheel ends and returns to the rotation state at a constant speed, the state is again balanced with the biasing force of the spring 45 as shown in FIG.

  The variable inertia flywheel 180 of the present embodiment is not limited to the configuration shown in FIG. Such a mechanical configuration does not cause a change in the moment of inertia, but may have a configuration in which the moment of inertia is changed by an external control signal. In that case, when the establishment of the condition that the rotation speed of the servo motor 112 is decelerated by the load is detected, the control for increasing the moment of inertia is performed, and the establishment of the condition for accelerating the rotation speed of the servo motor 112 is detected. In this case, the present invention can be implemented by performing control that reduces the moment of inertia.

  As a variable inertia flywheel having such a configuration, the flywheel is composed of two parts, a main body and a separation part that can be connected to or separated from the main body, and the separation part is normally connected to the main body by a permanent magnet provided in the main body. When the moment of inertia should be reduced, an electromagnet arranged around the separation portion is excited to generate a magnetic force larger than that of the permanent magnet, and the separation portion is attracted to the electromagnet and separated from the main body. . In the variable inertia flywheel having such a configuration, the inertia moment of the variable inertia flywheel can be controlled from the outside by switching energization to the electromagnet. When such a variable inertia flywheel is applied to the present embodiment, for example, when the condition for reducing the rotational speed of the servo motor 112 is satisfied, the electromagnet should be turned off to accelerate the rotational speed of the servo motor 112. When the condition is satisfied, the electromagnet is energized.

It is a perspective view which shows schematic structure of the engine which concerns on an Example. 1 is a schematic exploded perspective view of an engine and a compression ratio changing mechanism according to Embodiment 1. FIG. It is sectional drawing of the engine and compression ratio change mechanism which concern on an Example. It is a control block diagram for performing compression ratio variable control concerning an example. It is a conceptual diagram which shows the target compression ratio map which concerns on an Example. It is the figure which illustrated the relationship between the rotational speed of a servomotor, and the maximum value of the load (required torque) applied to a servomotor when changing a compression ratio to a target compression ratio. It is a flowchart showing the rotation speed control routine of the servomotor which concerns on an Example. 6 is a schematic exploded perspective view of an engine and a compression ratio changing mechanism according to Embodiment 2. FIG. FIG. 6 is a diagram illustrating a schematic configuration of a variable inertia flywheel according to a second embodiment. 9A shows a state where the flywheel is moving at a constant speed, FIG. 9B shows a state where the flywheel is accelerating, and FIG. 9C shows a state where the flywheel is decelerating.

Explanation of symbols

100 Engine 102 Cylinder 103 Cylinder block 104 Crankcase 105 Cam housing hole 106 Bolt 107 Cap 108 Bearing housing hole 109 Cam shaft 109a Shaft portion 109b Cam portion 109c Movable bearing portion 109d Mounting portion 110 Worm wheels 111a, 111b Worm 112 Servo motor 115 Crank Shaft 130 Bump 132 Standing wall 160 ECU
161 Throttle sensor 162 Accelerator opening sensor 163 Crank angle sensor 164 Motor rotation sensor 165 Water temperature sensor 166 In-cylinder pressure sensor 170 Piston 171 Connecting rod 180A, 180B Variable inertia flywheel 181 Shaft 40 Variable inertia moment portion 41 Flywheel main body 42 Groove 43 First 1 moving body 44 2nd moving body 45 Spring 46 Center of rotation

Claims (4)

A driving source;
The internal combustion engine has at least one movable member that operates by a driving force output from the driving source, and changes a combustion chamber volume and / or a piston stroke by the operation of the movable member by the driving force. A compression ratio changing mechanism capable of changing the compression ratio of
Control means for controlling the operation speed of the movable member to a speed not included in a predetermined prohibition speed range when changing the compression ratio of the internal combustion engine to a predetermined target compression ratio by the compression ratio changing mechanism;
Equipped with a,
The prohibited speed range is a condition that when the movable member is operated at the operating speed, the load applied to the drive source exceeds a predetermined reference value when the compression ratio is changed to the target compression ratio by the compression ratio changing mechanism. A range of operating speeds that satisfy
The control means determines a target speed of the operating speed of the movable member according to the target compression ratio, and when the target speed is a speed included in the prohibited speed range, it is included in the prohibited speed range. Calculating a corrected target speed obtained by correcting the target speed so that the corrected target speed is the final control target value of the operating speed of the movable member,
The upper limit value of the prohibited speed range is determined by the load applied to the driving source when the compression ratio is changed to the target compression ratio by the compression ratio changing mechanism when the movable member is operated at the operation speed. A control device for a compression ratio changing mechanism of an internal combustion engine, wherein the control device is determined based on an upper limit value of an operating speed that satisfies a condition that operation of a member may stop. In claim 1 ,
The lower limit value of the prohibited speed range is determined by the load applied to the drive source when the compression ratio is changed to the target compression ratio by the compression ratio changing mechanism when the movable member is operated at the operation speed. An operation speed that satisfies the condition that the load applied to the drive source is larger than a predetermined reference value when the operation of the member may stop and the movable member in the stopped state is operated again at the operation speed. A control device for a compression ratio changing mechanism of an internal combustion engine, characterized in that it is determined based on a lower limit value of the internal combustion engine. In claim 2 ,
The control apparatus for a compression ratio changing mechanism of an internal combustion engine, wherein the reference value is determined based on a maximum value of a driving force that can be output from the driving source. In any one of claims 1 to 3
In the middle of the path through which the driving force of the driving source is transmitted to the movable member,
When the condition that the operating speed of the movable member is decelerated is satisfied, the moment of inertia increases,
A control device for a compression ratio changing mechanism of an internal combustion engine, comprising: a variable inertia flywheel that reduces a moment of inertia when a condition for accelerating an operation speed of the movable member is satisfied.

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