JP6683560B2 - Control device for internal combustion engine and control method thereof - Google Patents

Description

  The present invention relates to a control device for an internal combustion engine and a control method thereof.

  In the control of the variable compression ratio mechanism, a compression ratio sensor that detects the compression ratio from the rotation angle of the drive shaft of the multi-link mechanism is used, as described in JP 2006-226133 A (Patent Document 1). There is. The compression ratio sensor is a relative angle sensor that detects the rotation angle of the drive shaft connected to the output shaft of the actuator through the reduction gear, as a relative angle in consideration of the reduction ratio of the reduction gear with respect to the rotation angle of the actuator, And an absolute angle sensor for detecting the absolute angle of the drive shaft. Then, when the internal combustion engine is started, the output value of the absolute angle sensor is obtained as a base point, and then the rotation angle of the drive shaft is obtained from the output value of the relative angle sensor in consideration of the base point.

JP, 2006-226133, A

  By the way, the absolute angle sensor has, for example, tolerance, variation due to thermal expansion, variation due to accuracy of the sensor itself, and variation due to input circuit of the controller. For this reason, in the absolute angle sensor, since a plurality of variations are accumulated, the detection accuracy of the absolute angle may decrease, and the accuracy of the base point may decrease. When the accuracy of the base point decreases, the accuracy of the drive shaft rotation angle obtained from the output value of the relative angle sensor in consideration of the base point also decreases. It will be difficult.

  Therefore, an object of the present invention is to provide a control device for an internal combustion engine and a control method for the same, in which the control accuracy of a controlled device is improved.

  Therefore, the control device of the internal combustion engine uses the rotation angle of the drive shaft connected to the output shaft of the actuator through the speed reducer as a relative angle in consideration of the reduction ratio of the speed reducer with respect to the rotation angle of the actuator. The control target device is controlled based on the output value of the relative angle sensor for detecting and the output value of the absolute angle sensor for detecting the absolute angle of the drive shaft. At this time, the control device of the internal combustion engine obtains the rotation angle of the drive shaft from the output value of the relative angle sensor, with the output value of the absolute angle sensor at the start of the internal combustion engine as a base point. Then, when the rotation angle of the drive shaft is larger than the first predetermined angle, the control device of the internal combustion engine controls the control target device based on the rotation angle of the drive shaft, and the rotation angle of the drive shaft is the first predetermined angle. In the following cases, the controlled device is controlled based on the output value of the absolute angle sensor.

  According to the present invention, it is possible to improve the control accuracy of the control target device.

FIG. 1 is a system diagram showing an example of a vehicle internal combustion engine. It is a partial enlarged view showing an example of a stopper mechanism. It is a flow chart which shows an example of learning processing of a standard position and an operating range. It is a time chart which shows an example of learning processing. It is a diagram which shows an example of the relationship between the rotation angle of a control shaft, and a compression ratio. It is a flow chart which shows an example of absolute angle calculation processing. It is a flow chart which shows an example of relative angle calculation processing. It is a flow chart which shows a 1st embodiment of normal control processing. It is explanatory drawing of the switching process of the control angle by 1st Embodiment. It is explanatory drawing of the correction process of the relative angle by 1st Embodiment. It is a flow chart which shows a 2nd embodiment of normal control processing. It is a flow chart which shows a 2nd embodiment of normal control processing. It is explanatory drawing of the switching process of the control angle by 2nd Embodiment. It is a flow chart which shows the modification of switching processing of a control angle. It is explanatory drawing of the switching process of the control angle by a modification. It is a flowchart which shows the process which avoids interference with a stopper mechanism. It is an explanatory view of switching processing of a control angle by avoidance processing.

Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 shows an example of an internal combustion engine for a vehicle.

  The internal combustion engine 100 includes a cylinder block 110, a piston 120 reciprocally fitted in a cylinder bore 112 of the cylinder block 110, a cylinder head 130 having an intake port 130A and an exhaust port 130B, an intake port 130A and an exhaust port. It has an intake valve 132 and an exhaust valve 134 that open and close the opening end of the port 130B.

  The piston 120 is connected to the crankshaft 140 via a connecting rod (connecting rod) 150 including a lower link 150A and an upper link 150B. A combustion chamber 160 is formed between the crown surface 120A of the piston 120 and the lower surface of the cylinder head 130. A spark plug 170 for igniting a mixture of fuel and air is attached to a substantially central portion of the cylinder head 130 forming the combustion chamber 160.

  Further, the internal combustion engine 100 changes the compression ratio by changing the volume of the variable valve timing (VTC: Valve Timing Control) mechanism 180 that changes the phase with respect to the crankshaft 140 during the opening period of the intake valve 132, and the combustion chamber 160. And a variable compression ratio (VCR) mechanism 190 that makes variable. Here, the VCR mechanism 190 is given as an example of the control target device.

  The VTC mechanism 180 changes the phase of the intake camshaft 200 with respect to the crankshaft 140 by, for example, an actuator such as an electric motor, thereby keeping the operating angle of the intake valve 132 constant and maintaining the center of the operating angle of the intake valve 132. Advance or retard the phase. It should be noted that the VTC mechanism 180 is not limited to the phase of the intake valve 132, and can change the phase of at least one of the intake valve 132 and the exhaust valve 134.

  The VCR mechanism 190 makes the compression ratio of the internal combustion engine 100 variable by changing the volume of the combustion chamber 160 by, for example, a multi-link mechanism disclosed in Japanese Patent Laid-Open No. 2002-276446. Hereinafter, an example of the VCR mechanism 190 will be described.

  The crankshaft 140 has a plurality of journal parts 140A and a crank pin part 140B, and the journal part 140A is rotatably supported by a main bearing (not shown) of the cylinder block 110. The crank pin portion 140B is eccentric from the journal portion 140A, and the lower link 150A is rotatably connected thereto. The lower end of the upper link 150B is rotatably connected to one end of the lower link 150A by a connecting pin 152, and the upper end thereof is rotatably connected to the piston 120 by a piston pin 154. The control link 192 has an upper end side rotatably connected to the other end of the lower link 150A by a connecting pin 194, and a lower end side rotatably connected to a lower portion of the cylinder block 110 via a control shaft 196. More specifically, the control shaft 196 is rotatably supported by the engine body (cylinder block 110) and has an eccentric cam portion 196A that is eccentric from the center of rotation, and the eccentric cam portion 196A has a control link 192. The lower end is rotatably fitted. The rotational position of the control shaft 196 is controlled by the compression ratio control actuator 198 using an electric motor. Here, the control shaft 196 is cited as an example of the drive shaft. Further, the compression ratio control actuator 198 is given as an example of the actuator.

  In the VCR mechanism 190 using such a multiple link mechanism, when the control shaft 196 is rotated by the compression ratio control actuator 198, the center position of the eccentric cam portion 196A, that is, relative to the engine body (cylinder block 110). The position changes. As a result, when the swing support position at the lower end of the control link 192 changes, the position of the piston 120 at the piston top dead center (TDC) increases or decreases, and the volume of the combustion chamber 160 increases or decreases, and the internal combustion engine 100 The compression ratio of is changed. At this time, when the operation of the compression ratio control actuator 198 is stopped, the reciprocating motion of the piston 120 causes the control link 192 to rotate with respect to the eccentric cam portion 196A of the control shaft 196, and the compression ratio shifts to the low compression side. .

  As shown in FIG. 2, the VCR mechanism 190 is provided with a stopper mechanism 210 that restricts the displacement (rotation) of the control shaft 196 when the control shaft 196 rotates beyond the normal control range. The stopper mechanism 210 has a substantially fan-shaped first member 210A in which essential parts are fixed to the control shaft 196, and a plate-shaped second member 210B fixed in the cylinder block 110. The first member 210A rotates integrally with the control shaft 196. The second member 210B defines the central angle of the first member 210A when the control shaft 196 rotates beyond the maximum compression ratio (upper limit) or the minimum compression ratio (lower limit), which is a normal control range. It comes into contact with the side and regulates the displacement of the control shaft 196, which is an example of a mechanical member. Here, since the stopper mechanism 210 functions when the control shaft 196 exceeds the normal control range, the first member 210A and the second member 210B do not come into contact with each other in the normal control. It is possible to suppress the generation of abnormal noise. The stopper mechanism 210 is used not only for restricting the displacement of the control shaft 196, but also for learning the reference position of the control shaft 196 as described later.

  The stopper mechanism 210 only needs to be able to regulate the displacement of at least one of the maximum compression ratio side and the minimum compression ratio side with respect to the rotation of the control shaft 196. Further, the stopper mechanism 210 is not limited to the substantially fan-shaped first member 210A and the plate-shaped second member 210B, and it is sufficient that the displacement of the control shaft 196 is restricted by two or more members having other shapes.

  The VTC mechanism 180 and the VCR mechanism 190 are electronically controlled by a VTC controller 220 and a VCR controller 230, which incorporate a processor such as a microcomputer. The VTC controller 220 and the VCR controller 230 are connected to an engine controller 250 that incorporates a processor such as a microcomputer that electronically controls the internal combustion engine 100 via a CAN (Controller Area Network) 240 that is an example of an in-vehicle network, for example. ing. Therefore, between the VTC controller 220, the VCR controller 230, and the engine controller 250, arbitrary data can be transmitted and received via the CAN 240. The vehicle-mounted network is not limited to the CAN 240, and a known network such as FlexRay (registered trademark) can be used. Here, the VCR controller 230 is mentioned as an example of a control device.

  As an example of the operating state of the internal combustion engine 100, the engine controller 250 receives output signals of a rotational speed sensor 260 that detects a rotational speed Ne of the internal combustion engine 100 and a load sensor 270 that detects a load Q of the internal combustion engine 100. It has been entered. Here, as the load Q of the internal combustion engine 100, for example, a state quantity that is closely related to torque, such as intake negative pressure, intake flow rate, supercharging pressure, accelerator opening, throttle opening, etc., can be used. The engine controller 250 refers to, for example, a map in which target values that match the rotation speed and the load are set, and the target angle of the VTC mechanism 180 and the VCR mechanism 190 according to the rotation speed Ne and the load Q of the internal combustion engine 100. The target compression ratios are calculated respectively. Then, the engine controller 250 transmits the target angle and the target compression ratio to the VTC controller 220 and the VCR controller 230 via the CAN 240, respectively. Note that the engine controller 250 is not limited to the output signals of the rotation speed sensor 260 and the load sensor 270, but also outputs the rotation speed Ne and the load Q of the internal combustion engine 100 from another controller (not shown) connected via the CAN 240. It can also be read.

  The VTC controller 220 that has received the target angle controls the drive current output to the actuator of the VTC mechanism 180 so that the actual angle (real angle) detected by the sensor (not shown) converges to the target angle. Further, the VCR controller 230 that has received the target compression ratio outputs it to the compression ratio control actuator 198 of the VCR mechanism 190 so that the actual compression ratio (actual compression ratio) detected by the sensor described later converges to the target compression ratio. Drive current is controlled. By doing so, the VTC mechanism 180 and the VCR mechanism 190 are controlled to target values according to the operating state of the internal combustion engine 100.

  The compression ratio sensor that detects the actual compression ratio of the internal combustion engine 100 uses the rotation angle of the control shaft 196 connected to the output shaft of the compression ratio control actuator 198 via the speed reducer 198A as the rotation angle of the compression ratio control actuator 198. On the other hand, it includes a relative angle sensor 280 that detects a relative angle in consideration of the reduction ratio of the speed reducer 198A, and an absolute angle sensor 290 that detects an absolute angle of the control shaft 196. Here, the relative angle sensor 280 is composed of, for example, a resolver sensor incorporated in the compression ratio control actuator 198, and detects the rotation angle of its output shaft in the range of 0 to 360 °. The absolute angle sensor 290 is composed of, for example, a resolver sensor attached to the control shaft 196, and detects its rotation angle within a range of 0 to 360 °.

  Then, the VCR controller 230 detects the rotation angle of the control shaft 196, that is, the compression ratio of the internal combustion engine 100, from the output value of the relative angle sensor 280, with the output value of the absolute angle sensor 290 at the time of engine start as a base point. This is because the relative angle sensor 280 has a high resolution, for example, 0 ° and 360 ° of the same phase cannot be distinguished, and the absolute angle sensor 290 can detect the absolute angle of the control shaft 196, but the resolution is high. Is low.

  The relative angle sensor 280 and the absolute angle sensor 290 are examples of the relative angle detection means and the absolute angle detection means, respectively. However, the relative angle detecting means may indirectly detect the relative angle of the control shaft 196 from the operation amount of the compression ratio control actuator 198.

  The VCR controller 230 learns the reference position for control, for example, when the initialization request flag output from the diagnostic tool connected to the CAN 240 changes from LOW to HI in a vehicle assembly plant. That is, the VCR controller 230 changes the compression ratio of the internal combustion engine 100 to the high compression ratio side, and when the control shaft 196 is in a state where the stopper mechanism 210 restricts the displacement to the high compression ratio side, The output value of the absolute angle sensor 290 is set as the reference position. Since this reference position can be referred to in the subsequent control, it is written in a non-volatile memory such as a flash ROM (Read Only Memory).

  FIG. 3 shows an example of the learning process of the reference position and the operating range, which is executed by the processor of the VCR controller 230 according to the control program stored in the nonvolatile memory. Note that this learning process is executed when the initialization request flag of the diagnostic tool changes from LOW to HI, and is executed during self-shutdown, for example, when the vehicle travels for a predetermined time or for a predetermined distance. You can also

  In step 1 (abbreviated as “S1” in the figure. The same applies hereinafter), the processor of the VCR controller 230 outputs a drive signal to the compression ratio control actuator 198 of the VCR mechanism 190, thereby compressing the internal combustion engine 100. The compression ratio control actuator 198 is rotated so that the ratio is changed to the high compression ratio side. At this time, the processor of the VCR controller 230 controls the rotation of the compression ratio control actuator 198 by, for example, speed feedback control (hereinafter the same).

  In step 2, the processor of the VCR controller 230 determines whether or not the compression ratio control actuator 198 is stopped, for example, via whether or not the output value of the relative angle sensor 280 has changed. When the compression ratio control actuator 198 stops, the first member 210A of the stopper mechanism 210 contacts the second member 210B, and the displacement of the control shaft 196 toward the high compression ratio side is restricted. Then, if the processor of the VCR controller 230 determines that the compression ratio control actuator 198 is stopped, the process proceeds to step 3 (Yes), while if it is determined that the compression ratio control actuator 198 is not stopped, the process is performed. Return to 1 (No).

  In step 3, the processor of the VCR controller 230 determines whether or not the first predetermined time has elapsed since the compression ratio control actuator 198 was stopped, for example, using the built-in timing function. Here, the first predetermined time period secures a time period until the displacement of the control shaft 196 toward the high compression ratio side is reliably regulated, and for example, the output of the compression ratio control actuator 198. It can be appropriately set according to the characteristics and the reduction ratio. Then, the processor of the VCR controller 230 advances the processing to step 4 if it determines that the first predetermined time has elapsed (Yes), and waits if it determines that the first predetermined time has not elapsed (No). .

  In step 4, the processor of the VCR controller 230 writes the output value of the absolute angle sensor 290 in the non-volatile memory. That is, in the state where the first member 210A of the stopper mechanism 210 is pressed against the second member 210B, the absolute angle of the control shaft 196 can be uniquely specified, so the output value of the absolute angle sensor 290 in that state is Learn as the reference position (0 °).

  In step 5, the processor of the VCR controller 230 outputs a drive signal to the compression ratio control actuator 198 of the VCR mechanism 190, for example, so that the compression ratio of the internal combustion engine 100 shifts to the low compression ratio side. The control actuator 198 is rotated.

  In step 6, the processor of the VCR controller 230 determines whether or not the compression ratio control actuator 198 has stopped, for example, through whether or not the output value of the relative angle sensor 280 has changed. When the compression ratio control actuator 198 is stopped, the first member 210A of the stopper mechanism 210 contacts the second member 210B, and the displacement of the control shaft 196 toward the low compression ratio side is restricted. Then, if the processor of the VCR controller 230 determines that the compression ratio control actuator 198 is stopped, the process proceeds to step 7 (Yes), while if it is determined that the compression ratio control actuator 198 is not stopped, the process is performed. Return to 5 (No).

  In step 7, the processor of the VCR controller 230 determines whether or not the second predetermined time has elapsed since the compression ratio control actuator 198 was stopped, for example, using the built-in timing function. Here, the second predetermined time period secures a time period until the displacement of the control shaft 196 toward the low compression ratio side is surely restricted, and for example, the output of the compression ratio control actuator 198. It can be appropriately set according to the characteristics and the reduction ratio. The second predetermined time may be the same as the first predetermined time or may be different from the first predetermined time. Then, the processor of the VCR controller 230 advances the process to step 8 if it determines that the second predetermined time has elapsed (Yes), and waits if it determines that the second predetermined time has not elapsed (No). .

  In step 8, the processor of the VCR controller 230 sets the operating range of the control shaft 196 such that the displacement of the compression ratio to the high compression ratio side is restricted and the displacement of the compression ratio to the low compression ratio side is restricted. The range defined by and is set, and this is written in the non-volatile memory. This operating range contributes to, for example, suppressing the control shaft 196 from attempting to rotate beyond the operating range, and reducing the amount of heat generation and power consumption of the compression ratio control actuator 198.

  According to this learning processing, as shown in FIG. 4, when the initialization request flag output from the diagnostic tool changes from LOW to HI, the control shaft 196 of the VCR mechanism 190 rotates toward the high compression ratio side, and the relative angle sensor The output values of the 280 and the absolute angle sensor 290 start to gradually change toward the displacement restriction position on the high compression ratio side. As a result of the control shaft 196 changing toward the restriction position on the high compression ratio side, the first member 210A of the stopper mechanism 210 abuts on the second member 210B, and the displacement to the high compression ratio side is restricted. When the first predetermined time has elapsed, the output value of the absolute angle sensor 290 is learned (stored) as the reference position.

  When the learning of the reference position is completed, the control shaft 196 of the VCR mechanism 190 rotates to the low compression ratio side, and the output values of the relative angle sensor 280 and the absolute angle sensor 290 gradually move toward the displacement restriction position on the low compression ratio side. Begins to change to. As a result of the control shaft 196 changing toward the restriction position on the low compression ratio side, the first member 210A of the stopper mechanism 210 contacts the second member 210B, and the displacement to the low compression ratio side is restricted. When the second predetermined time has elapsed, the operating range of the compression ratio control actuator 198 is set.

Here, the control outline of the VCR mechanism 190 will be described.
The VCR controller 230 obtains the rotation angle of the control shaft 196 from the output value of the relative angle sensor 280 with the output value of the absolute angle sensor 290 at the time of starting the internal combustion engine 100 as a base point. Then, the VCR controller 230 feedback-controls the compression ratio control actuator 198 so that the rotation angle of the control shaft 196 becomes a target angle according to the target compression ratio.

  Since the absolute angle sensor 290 has a low resolution, the base point obtained from the output value thereof includes an error that is offset to the plus side or the minus side with respect to the true value and that corresponds to the resolution. Consider a case where the relationship between the rotation angle of the control shaft 196 and the compression ratio of the internal combustion engine 100 increases non-linearly as the rotation angle of the control shaft 196 decreases, as shown in FIG. If the base point includes an error on the plus side, the rotation angle of the control shaft 196 obtained from this also becomes larger than the true value, and the rotation angle of the control shaft 196 is further increased despite the maximum compression ratio. It is controlled to make it smaller. In this case, depending on the magnitude of the error, the operation of the compression ratio control actuator 198 may be continued even though the displacement of the control shaft 196 is restricted by the stopper mechanism 210.

  Therefore, the VCR controller 230 rotates the control shaft 196 obtained from the output value of the relative angle sensor 280 with the output value of the absolute angle sensor 290 at the start of the internal combustion engine 100 as a base point, as described in detail below. When the angle is larger than the first predetermined angle (predetermined angle), the VCR mechanism 190 is controlled based on this rotation angle. Further, when the rotation angle of the control shaft 196 is equal to or smaller than the first predetermined angle, the VCR controller 230 controls the VCR mechanism 190 based on the output value of the absolute angle sensor 290 instead of this rotation angle.

  FIG. 6 shows an example of an absolute angle calculation process in which the processor of the VCR controller 230 calculates the rotation angle (absolute angle θa) of the control shaft 196 from the output value of the absolute angle sensor 290. The processor of the VCR controller 230 executes the absolute angle calculation process repeatedly every predetermined time t1 or each time the absolute angle θa is referred to.

In step 11, the processor of the VCR controller 230 reads the reference position from the non-volatile memory.
In step 12, the processor of the VCR controller 230 reads the output value of the absolute angle sensor 290.

In step 13, the processor of the VCR controller 230 calculates the absolute angle θa from the output value of the absolute angle sensor 290 in consideration of the reference position.
According to the absolute angle calculation process, the absolute angle θa is obtained from the output value of the absolute angle sensor 290, taking into consideration the learned reference position.

  FIG. 7 shows an example of a relative angle calculation process in which the processor of the VCR controller 230 calculates the rotation angle (relative angle θr) of the control shaft 196 from the output value of the relative angle sensor 280. The processor of the VCR controller 230 executes the relative angle calculation process repeatedly every predetermined time t2 or every time when the relative angle θr is referred to. Here, the predetermined time t2 may be the same as the predetermined time t1 or may be different from the predetermined time t1.

  In step 21, the processor of the VCR controller 230 determines whether or not the absolute angle θa of the control shaft 196 has been calculated. That is, if the absolute angle θa has not been calculated, the relative angle θr based on this point cannot be calculated. Therefore, the processor of the VCR controller 230 calculates the absolute angle θa necessary for calculating the relative angle θr. It is determined whether it has been completed. Then, the processor of the VCR controller 230 advances the process to step 22 if it determines that the absolute angle θa has been calculated (Yes), while ending the process if it determines that the absolute angle θa has not been calculated (Yes). No).

  In step 22, the processor of the VCR controller 230 determines whether or not this is the first process after the activation of the VCR controller 230. Here, whether or not it is the first process can be determined by, for example, a flag indicating that it is the first process. Then, the processor of the VCR controller 230 advances the process to step 23 if it determines that it is the first process (Yes), and advances the process to step 24 if it determines that it is not the first process (process after the second time). And proceed (No).

In step 23, the processor of the VCR controller 230 adopts the absolute angle θa as the relative angle θr of the control shaft 196 (relative angle θr = absolute angle θa).
In step 24, the processor of the VCR controller 230 reads the output value of the relative angle sensor 280.

  In step 25, the processor of the VCR controller 230 subtracts the output value of the relative angle sensor 280 in the previous process from the output value of the relative angle sensor 280 in the current process, for example, to thereby determine the output change amount of the relative angle sensor 280. To calculate.

  In step 26, the processor of the VCR controller 230 calculates the angle change amount by, for example, multiplying the output change amount of the relative angle sensor 280 by the reduction ratio of the speed reducer 198A.

  In step 27, the processor of the VCR controller 230 updates the relative angle θr of the control shaft 196 by adding the angle change amount to the calculated relative angle θr, for example. In short, the processor of the VCR controller 230 adds the angle change amount changed between the previous processing and the current processing to the relative angle θr calculated in the previous processing to obtain the latest relative angle θr. calculate.

  According to the relative angle calculation process, the absolute angle θa is adopted as the relative angle θr of the control shaft 196 in the first process after the activation of the VCR controller 230. That is, in the first process, the absolute angle θa is used as the base point for calculating the relative angle θr. Then, in the subsequent relative angle calculation process, the angle change amount is calculated from the change in the output value of the relative angle sensor 280 in consideration of this base point, and the angle change amount is added to the relative angle θr calculated in the previous process. By adding, the latest relative angle θr is sequentially calculated.

  FIG. 8 shows a first embodiment of the normal control processing of the VCR mechanism 190, which is repeatedly executed by the processor of the VCR controller 230 every predetermined time Δt. As a premise of the first embodiment, it is assumed that the correction flag indicating whether or not the relative angle θr of the control shaft 196 has been corrected is uncorrected (the same applies hereinafter).

  In step 31, the processor of the VCR controller 230 determines whether the relative angle θr of the control shaft 196 is less than or equal to the first predetermined angle θ1. Here, the first predetermined angle θ1 is a threshold value that defines the rotation angle at which the control shaft 196 does not hit the stopper mechanism 210 in the normal control range (see FIG. 2) even if the base point includes the maximum error. Then, for example, it can be appropriately set in consideration of the output error and the margin of the absolute angle sensor 290. Then, if the processor of the VCR controller 230 determines that the relative angle θr is the first predetermined angle θ1 or less, that is, the control shaft 196 may hit the stopper mechanism 210, the process proceeds to step 32 (Yes). . On the other hand, if the processor of the VCR controller 230 determines that the relative angle θr is larger than the first predetermined angle, that is, there is no possibility that the control shaft 196 hits the stopper mechanism 210, the process proceeds to step 33 (No). .

  In step 32, the processor of the VCR controller 230 controls the compression ratio control actuator 198 based on the absolute angle θa of the control shaft 196. Specifically, the processor of the VCR controller 230 feedback-controls the operation amount of the compression ratio control actuator 198 so that the absolute angle θa of the control shaft 196 converges to a target angle according to the target compression ratio.

  In step 33, the processor of the VCR controller 230 controls the compression ratio control actuator 198 based on the relative angle θr of the control shaft 196. Specifically, the processor of the VCR controller 230 feedback-controls the operation amount of the compression ratio control actuator 198 so that the relative angle θr of the control shaft 196 converges to a target angle according to the target compression ratio.

  In step 34, the processor of the VCR controller 230 determines whether or not the absolute angle θa of the control shaft 196 is the lower limit (control lower limit) of the normal control range. Here, the control lower limit is a threshold value for determining whether or not the compression ratio of the internal combustion engine 100 is maximized, and can be appropriately set, for example, according to the operating characteristics of the VCR mechanism 190. Then, the processor of the VCR controller 230 advances the process to step 35 if it determines that the absolute angle θa is the control lower limit (Yes), and ends the process if it determines that the absolute angle θa is larger than the control lower limit (Yes). No).

  In step 35, the processor of the VCR controller 230 determines whether or not the state where the absolute angle θa of the control shaft 196 is the control lower limit continues for a predetermined time. Here, the predetermined time is a threshold value for determining whether or not the control shaft 196 has converged to the target angle, and, for example, in consideration of the operating characteristic of the VCR mechanism 190 and the output characteristic of the absolute angle sensor 290. It can be set appropriately. If the processor of the VCR controller 230 determines that the state where the absolute angle θa is the control lower limit continues for the predetermined time, the process proceeds to step 36 (Yes) while the absolute angle θa is the control lower limit. If it is determined that does not last for the predetermined time, the process is terminated (No).

  In step 36, the processor of the VCR controller 230 determines whether or not the relative angle θr of the control shaft 196 is uncorrected by referring to the correction flag. Then, the processor of the VCR controller 230 advances the process to step 37 if it determines that the relative angle θr has not been corrected (Yes), and ends the process if it determines that the relative angle θr has been corrected (Yes). No).

In step 37, the processor of the VCR controller 230 adopts the absolute angle θa as the relative angle θr of the control shaft 196.
At step 38, the processor of the VCR controller 230 changes the correction flag to corrected.

  According to the first embodiment of the normal control process, as shown in FIG. 9, when the relative angle θr of the control shaft 196 is larger than the first predetermined angle θ1, the control shaft 196 causes the stopper mechanism 210 to fall within the normal control range. Therefore, the compression ratio control actuator 198 is controlled based on the relative angle θr (see the thick line in the figure). On the other hand, if the relative angle θr of the control shaft 196 is equal to or smaller than the first predetermined angle θ1, the control shaft 196 may hit the stopper mechanism 210 in the normal control range. Therefore, instead of the relative angle θr, the absolute angle θa. The compression ratio control actuator 198 is controlled based on the above (see the thick line in the figure).

  Therefore, when the relative angle θr of the control shaft 196 is less than or equal to the first predetermined angle θ1, the absolute angle θa of the control shaft 196 that does not consider the base point including the error is adopted, and thus the detection of the rotation angle of the control shaft 196 is performed. The accuracy can be improved. Further, since the detection accuracy of the rotation angle of the control shaft 196 is improved, the control accuracy of the VCR mechanism 190 is improved and the interference between the intake valve 132 and the exhaust valve 134 and the piston 120 can be suppressed.

  When the absolute angle θa of the control shaft 196 remains at the control lower limit for a predetermined time, the absolute angle θa is reset as the relative angle θr as shown in FIG. 10 only when the relative angle θr is uncorrected. To be done. That is, when the above condition is satisfied, the relative angle θr is corrected by using the absolute angle θa at that time as an initial value, thereby reducing the error of the base point and further improving the detection accuracy of the rotation angle of the control shaft 196. it can. Since the detection accuracy is improved after the relative angle θr is corrected, the compression ratio control actuator 198 may be controlled based on only the relative angle θr.

  By the way, when the relative angle θr of the control shaft 196 gradually decreases and reaches the first predetermined angle θ1, the rotation angle of the control shaft 196 is switched from the relative angle θr to the absolute angle θa. As shown, a step in which the rotation angle of the control shaft 196 is not continuous occurs. Therefore, as described below, when the relative angle θr of the control shaft 196 is larger than the first predetermined angle θ1 and less than the second predetermined angle θ2 which is larger than this, the rotation angle of the control shaft 196 is gradually increased. By changing it, the step difference at the time of switching can be made small.

  11 and 12 show a second embodiment of the normal control process of the VCR mechanism 190, which is repeatedly executed by the processor of the VCR controller 230 every predetermined time Δt. The description of the processing common to the first embodiment will be simplified for the purpose of eliminating duplicate description. If necessary, refer to the description of the first embodiment (same below).

  In step 41, the processor of the VCR controller 230 determines whether the relative angle θr of the control shaft 196 is less than or equal to the first predetermined angle θ1. Then, if the processor of the VCR controller 230 determines that the relative angle θr is equal to or smaller than the first predetermined angle θ1, the process proceeds to step 42 (Yes), while the relative angle θr is larger than the first predetermined angle θ1. If so, the process proceeds to step 48 (No).

  In step 42, the processor of the VCR controller 230 adopts the absolute angle θa of the control shaft 196 as the control angle θ for controlling the compression ratio control actuator 198 (control angle θ = absolute angle θa).

  In step 43, the processor of the VCR controller 230 determines whether the absolute angle θa of the control shaft 196 is the control lower limit. Then, if the processor of the VCR controller 230 determines that the absolute angle θa is the control lower limit, the process proceeds to step 44 (Yes), while if it determines that the absolute angle θa is larger than the control lower limit, the process proceeds to step 51. And proceed (No).

  In step 44, the processor of the VCR controller 230 determines whether or not the state where the absolute angle θa of the control shaft 196 is the control lower limit continues for a predetermined time. If the processor of the VCR controller 230 determines that the state where the absolute angle θa is the control lower limit continues for the predetermined time, the process proceeds to step 45 (Yes), while the absolute angle θa is the control lower limit. If it is determined that does not last for the predetermined time, the process proceeds to step 51 (No).

  At step 45, the processor of the VCR controller 230 determines whether the relative angle θr of the control shaft 196 is uncorrected. Then, if the processor of the VCR controller 230 determines that the relative angle θr is not corrected, the process proceeds to step 46 (Yes), while if it is determined that the relative angle θr is corrected, the process proceeds to step 51. And proceed (No).

At step 46, the processor of the VCR controller 230 adopts the absolute angle θa as the relative angle θr of the control shaft 196.
In step 47, the processor of the VCR controller 230 changes the correction flag to corrected. After that, the processor of the VCR controller 230 advances the process to step 51.

  At step 48, the processor of the VCR controller 230 determines whether the relative angle θr of the control shaft 196 is less than the second predetermined angle θ2. If the processor of the VCR controller 230 determines that the relative angle θr is less than the second predetermined angle θ2, the process proceeds to step 49 (Yes), while the relative angle θr is the second predetermined angle θ2 or more. If so, the process proceeds to step 50 (No).

In step 49, the processor of the VCR controller 230 calculates a control angle θ (intermediate value) that gradually changes the rotation angle of the control shaft 196 according to the relative angle θr of the control shaft 196, for example, from the formula shown below. To do. In the following equation, θr (θ2) represents the relative angle θr when the rotation angle is θ2, and θa (θ1) represents the absolute angle θa when the rotation angle is θ1.
Control angle θ = C1-C2 (θ2-θr)
C1 = θr (θ2)
C2 = {θr (θ2) -θa (θ1)} / (θ2-θ1)

  In step 50, the processor of the VCR controller 230 adopts the relative angle θr of the control shaft 196 as the control angle θ for controlling the compression ratio control actuator 198 (control angle θ = relative angle θr).

  In step 51, the processor of the VCR controller 230 controls the compression ratio control actuator 198 based on the control angle θ of the control shaft 196. Specifically, the processor of the VCR controller 230 feedback-controls the operation amount of the compression ratio control actuator 198 so that the control angle θ of the control shaft 196 converges to the target angle according to the target compression ratio.

  According to the second embodiment of the normal control process, as shown in FIG. 13, when the relative angle θr of the control shaft 196 is larger than the first predetermined angle θ1 and smaller than the second predetermined angle θ2, the compression ratio control is performed. The control angle θ for controlling the actuator 198 gradually changes (see the thick line). Therefore, the step difference when switching from the relative angle θr to the absolute angle θa becomes small, and the controllability of the compression ratio control actuator 198 can be improved. Note that other operations and effects are similar to those of the first embodiment described above, and thus description thereof will be omitted. If necessary, refer to the description of the first embodiment.

  In order to reduce the step difference at the time of switching, instead of the process of FIG. 12, a range in which the relative angle θr of the control shaft 196 is larger than the first predetermined angle θ1 and smaller than the second predetermined angle θ2 is as follows. In, the smaller one of the relative angle θr and the absolute angle θa may be adopted.

FIG. 14 shows an example of a modification in which the step difference at the time of switching is reduced.
At step 48, the processor of the VCR controller 230 determines whether the relative angle θr of the control shaft 196 is less than the second predetermined angle θ2. If the processor of the VCR controller 230 determines that the relative angle θr is less than the second predetermined angle θ2, the process proceeds to step 49 (Yes), while the relative angle θr is the second predetermined angle θ2 or more. If so, the process proceeds to step 50 '(No).

  At step 49, the processor of the VCR controller 230 determines whether the relative angle θr of the control shaft 196 is less than the absolute angle θa. Then, the processor of the VCR controller 230 advances the process to step 50 if it determines that the relative angle θr is less than the absolute angle θa (Yes), and executes the process if it determines that the relative angle θr is equal to or greater than the absolute angle θa. To Step 50 '(No).

  In step 50, the processor of the VCR controller 230 adopts the relative angle θr of the control shaft 196 as the control angle θ for controlling the compression ratio control actuator 198 (control angle θ = relative angle θr).

  In step 50 ', the processor of the VCR controller 230 adopts the absolute angle θa of the control shaft 196 as the control angle θ for controlling the compression ratio control actuator 198 (control angle θ = absolute angle θa).

  According to this modified example, as shown in FIG. 15, when the relative angle θr of the control shaft 196 is larger than the first predetermined angle θ1 and less than the second predetermined angle θ2, of the relative angle θr and the absolute angle θa. The compression ratio control actuator 198 is feedback-controlled based on the small angle (see the bold line). Therefore, it is possible to reduce the step when switching from the relative angle θr to the absolute angle θa while suppressing an increase in control load.

  By the way, if only the control shaft 196 is prevented from hitting the stopper mechanism 210, as shown in FIG. 16, based on the smaller one of the relative angle θr and the absolute angle θa of the control shaft 196 in the entire normal control range. Thus, the compression ratio control actuator 198 may be controlled.

  At step 61, the processor of the VCR controller 230 determines whether the relative angle θr of the control shaft 196 is less than the absolute angle θa. Then, the processor of the VCR controller 230 advances the process to step 62 if it determines that the relative angle θr is less than the absolute angle θa (Yes), and executes the process if it determines that the relative angle θr is equal to or greater than the absolute angle θa. To Step 63 (No).

In step 62, the processor of the VCR controller 230 controls the compression ratio control actuator 198 based on the relative angle θr of the control shaft 196.
In step 63, the processor of the VCR controller 230 controls the compression ratio control actuator 198 based on the absolute angle θa of the control shaft 196.

  By doing so, as shown in FIG. 17, the compression ratio control actuator 198 is controlled at an angle of the relative angle θr and the absolute angle θa of the control shaft 196 that is likely to hit the stopper mechanism 210. Interference between 196 and the stopper mechanism 210 can be avoided. Further, since the control load is smaller than that of the previous embodiment, the VCR controller 230 capable of high-speed processing can be mounted.

  The equipment to be controlled is not limited to the VCR mechanism 190, and the rotation angle of the drive shaft connected to the output shaft of the actuator via the speed reducer and the reduction ratio of the speed reducer to the rotation angle of the actuator are considered. It may be controlled as long as it is controlled based on the output value of the relative angle sensor that detects the relative angle and the output value of the absolute angle sensor that detects the absolute angle of the drive shaft.

Here, the technical idea that can be understood from the above-described embodiment will be described below.
(1) A relative angle sensor that detects a relative angle of a drive shaft connected to an output shaft of an actuator via a speed reducer as a relative angle in consideration of a reduction ratio of the speed reducer with respect to a rotation angle of the actuator. And an output value of an absolute angle sensor that detects an absolute angle of the drive shaft, and a control device for an internal combustion engine that controls a device to be controlled based on the absolute angle sensor when the internal combustion engine is started. When the rotation angle of the drive shaft obtained from the output value of the relative angle sensor is larger than a first predetermined angle with respect to the output value of, the control target device is controlled based on the rotation angle of the drive shaft. When the rotation angle of the drive shaft is less than or equal to the first predetermined angle, the control target device is controlled based on the output value of the absolute angle sensor.

(2) When the rotation angle of the drive shaft is greater than the first predetermined angle and less than a second predetermined angle that is greater than the first predetermined angle, the output of the absolute angle sensor at the first predetermined angle The control target device is controlled based on an intermediate value between the value and the rotation angle of the drive shaft at the second predetermined angle.

(3) The intermediate value is an angle obtained by correcting the rotation angle of the drive shaft according to the rotation angle of the drive shaft and the output value of the absolute angle sensor.
(4) The intermediate value is the smaller of the rotation angle of the drive shaft and the output value of the absolute angle sensor.

(5) When the output value of the absolute angle sensor remains at the control lower limit for a predetermined time, the output value of the absolute angle sensor is reset as a base point.
(6) The base point is reset only once between the time when the internal combustion engine is started and the time when the internal combustion engine is stopped.

(7) After the base point is reset, the control target device is controlled based on the rotation angle of the drive shaft.
(8) The output value of the absolute angle sensor is corrected based on the reference angle learned by contacting the drive shaft with a stopper that restricts the rotation of the drive shaft.
(9) The device to be controlled is a variable compression ratio mechanism that makes the compression ratio of the internal combustion engine variable.

(10) A relative angle sensor for detecting a relative angle of a drive shaft connected to an output shaft of an actuator via a speed reducer as a relative angle in consideration of a reduction ratio of the speed reducer with respect to a rotation angle of the actuator. Output value of the absolute angle sensor for detecting the absolute angle of the drive shaft, and the control device of the internal combustion engine for controlling the device to be controlled based on the output of the absolute angle sensor when the internal combustion engine is started. When the rotation angle of the drive shaft obtained from the output value of the relative angle sensor is larger than a first predetermined angle with a value as a base point, the control target device is controlled based on the rotation angle of the drive shaft, When the rotation angle of the drive shaft is equal to or less than the first predetermined angle, the control target device is controlled based on the output value of the absolute angle sensor.

(11) A relative angle sensor that detects a relative angle of a drive shaft connected to an output shaft of an actuator via a speed reducer as a relative angle in consideration of a reduction ratio of the speed reducer with respect to a rotation angle of the actuator. And an output value of an absolute angle sensor that detects an absolute angle of the drive shaft, and a control device for an internal combustion engine that controls a device to be controlled based on the absolute angle sensor when the internal combustion engine is started. The control target is controlled based on the smaller one of the rotation angle of the drive shaft obtained from the output value of the relative angle sensor and the output value of the absolute angle sensor with the output value of 1 as the base point.

(12) A relative angle sensor that detects a relative angle of a drive shaft connected to an output shaft of an actuator via a speed reducer as a relative angle in consideration of a reduction ratio of the speed reducer with respect to a rotation angle of the actuator. Output value of the absolute angle sensor for detecting the absolute angle of the drive shaft, and the control device of the internal combustion engine for controlling the device to be controlled based on the output of the absolute angle sensor when the internal combustion engine is started. The controlled object is controlled based on a smaller angle of the rotation angle of the drive shaft obtained from the output value of the relative angle sensor and the output value of the absolute angle sensor with the value as a base point.

(13) Relative angle detection for detecting the relative angle of the drive shaft connected to the output shaft of the actuator through the speed reducer as the relative angle in consideration of the reduction ratio of the speed reducer with respect to the rotation angle of the actuator. An output value of the means, an output value of an absolute angle detection means for detecting the absolute angle of the drive shaft, and a control device for an internal combustion engine for controlling a device to be controlled,
When the rotation angle of the drive shaft obtained from the output value of the relative angle detection means is larger than a predetermined angle with the output value of the absolute angle detection means at the time of starting the internal combustion engine as a base point, the rotation angle of the drive shaft Based on the output value of the absolute angle detection means, the control target device is controlled based on the output value of the absolute angle detecting means when the rotation angle of the drive shaft is equal to or less than the predetermined angle.

100 Internal combustion engine 190 VCR mechanism (controlled device)
196 Control shaft (drive shaft)
198 Compression ratio control actuator (actuator)
198A Reducer 230 VCR controller (control device)
280 Relative angle sensor (relative angle detection means)
290 Absolute angle sensor (Absolute angle detection means)

Claims (5)

Output value of a relative angle sensor that detects a rotation angle of a drive shaft connected to an output shaft of an actuator via a speed reducer as a relative angle in consideration of a reduction ratio of the speed reducer with respect to a rotation angle of the actuator. And an output value of an absolute angle sensor that detects an absolute angle of the drive shaft, and a control device for an internal combustion engine that controls a control target device based on the:
When the rotation angle of the drive shaft obtained from the output value of the relative angle sensor is larger than a first predetermined angle with the output value of the absolute angle sensor at the time of starting the internal combustion engine as a base point, the rotation angle of the drive shaft Based on the output value of the absolute angle sensor, when the rotation angle of the drive shaft is less than or equal to the first predetermined angle, the control target device is controlled based on the output value of the absolute angle sensor.
A control device for an internal combustion engine, characterized in that: When the rotation angle of the drive shaft is larger than the first predetermined angle and smaller than a second predetermined angle that is larger than the first predetermined angle, the output value of the absolute angle sensor at the first predetermined angle and the output value Controlling the device to be controlled based on an intermediate value between the rotation angle of the drive shaft and the second predetermined angle;
The control device for an internal combustion engine according to claim 1, wherein: When the state in which the output value of the absolute angle sensor is at the control lower limit lasts for a predetermined time, the output value of the absolute angle sensor is reset as a base point,
The control device for an internal combustion engine according to claim 1 or 2, characterized in that. Output value of a relative angle sensor that detects a rotation angle of a drive shaft connected to an output shaft of an actuator via a speed reducer as a relative angle in consideration of a reduction ratio of the speed reducer with respect to a rotation angle of the actuator. And an output value of an absolute angle sensor that detects the absolute angle of the drive shaft, and a control device for an internal combustion engine that controls a device to be controlled based on the output value,
When the rotation angle of the drive shaft obtained from the output value of the relative angle sensor is larger than a first predetermined angle with the output value of the absolute angle sensor at the time of starting the internal combustion engine as a base point, the rotation angle of the drive shaft Based on the output value of the absolute angle sensor, when the rotation angle of the drive shaft is less than or equal to the first predetermined angle, the control target device is controlled based on the output value of the absolute angle sensor.
A method for controlling an internal combustion engine, comprising: Output of relative angle detecting means for detecting the rotation angle of the drive shaft connected to the output shaft of the actuator via the speed reducer as the relative angle in consideration of the reduction ratio of the speed reducer with respect to the rotation angle of the actuator. A control device for an internal combustion engine that controls a device to be controlled based on a value and an output value of an absolute angle detection means that detects an absolute angle of the drive shaft,
When the rotation angle of the drive shaft obtained from the output value of the relative angle detection means is larger than a predetermined angle, using the output value of the absolute angle detection means at the time of starting the internal combustion engine as a base point, the rotation angle of the drive shaft Controlling the control target device based on, when the rotation angle of the drive shaft is less than or equal to the predetermined angle, to control the control target device based on the output value of the absolute angle detection means,
A control device for an internal combustion engine, characterized in that: