JP2006307810A - Control device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device for an internal combustion engine, which suppresses torque fluctuation when a drive mode of an electric motor is switched and stabilizes output of the internal combustion engine. <P>SOLUTION: This control device is applied to the engine 100 equipped with a valve gear 11A converting rotation of a motor 12 into linear motion by a cam 21 and opening/closing an intake valve 2 of a cylinder 1 by the linear motion; and with a motor control device 40 driving the motor 12 in each of a normal rotation drive mode to continuously rotate the cam 21 in one direction and an oscillation drive mode to switch the rotational direction of the cam 21 during lifting of the intake valve 2. At the time of switching of the oscillation drive mode and the normal rotation drive mode, the motor control device 40 adjusts ignition timing of an ignition plug 4 to suppress torque fluctuation of the engine 100 expected to occur along with the switching of the drive modes. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a control device for an internal combustion engine including a valve operating mechanism that opens and closes an intake valve and an exhaust valve by an electric motor.

A cam for opening and closing the intake valve or the exhaust valve is rotationally driven by an electric motor, and this electric motor normalizes the normal rotation mode in which the cam is continuously rotated in one direction according to the operation state of the internal combustion engine and the rotation direction of the cam. There is known a valve drive system that is controlled by switching to a forward / reverse rotation mode (see Patent Document 1).
JP 2004-183612 A

  The valve lift curve in the forward rotation mode and the valve lift curve in the forward / reverse rotation mode (hereinafter also referred to as the swing mode) are different, so the intake air amount etc. changes intermittently when the drive mode of the motor is switched. However, there is a risk of torque fluctuations in the internal combustion engine.

  Therefore, an object of the present invention is to provide a control device for an internal combustion engine that can suppress torque fluctuation when switching the drive mode of the electric motor and can stabilize the output of the internal combustion engine.

  The control device of the present invention converts a rotary motion of an electric motor into a linear motion by a cam, and a valve mechanism that opens and closes a cylinder valve by the linear motion, and a forward rotation drive that continuously rotates the cam in one direction. A control device applied to an internal combustion engine comprising: a motor control means capable of driving the motor in each of a mode and a swing drive mode for switching a rotation direction of the cam during lift of the valve; The motor control means outputs the output of the internal combustion engine so as to suppress torque fluctuations of the internal combustion engine that are expected to occur in association with switching of the drive mode when switching between the swing drive mode and the forward drive mode. The above-described problem is solved by providing torque fluctuation suppressing means for adjusting the above (claim 1).

  According to the control device of the present invention, torque fluctuation at the time of switching the drive mode is suppressed by the torque fluctuation suppressing means, so that the output of the internal combustion engine at the time of switching the drive mode can be stabilized. The concept of torque fluctuation suppression according to the present invention includes partially canceling the change in torque of the internal combustion engine caused by switching the drive mode by adjusting the output of the internal combustion engine, and at the time of switching the drive mode. This includes both canceling out the change in torque of the engine to substantially zero by adjusting the output of the internal combustion engine, that is, canceling out.

  In one form of the control device of the present invention, the torque fluctuation suppressing means may adjust the output of the internal combustion engine based on the rotational speed of the internal combustion engine when the drive mode is switched (Claim 2). The torque fluctuation that is expected to occur with the switching of the drive mode changes according to the rotational speed of the internal combustion engine. For example, when the rotational speed of the internal combustion engine is high, the number of opening / closing of the valve per unit time is larger than when the rotational speed of the internal combustion engine is low. Therefore, the effect of the change in the lift curve of the valve due to the switching of the drive mode on the torque of the internal combustion engine is also greater when the rotational speed of the internal combustion engine is higher. Thus, by adjusting the output of the internal combustion engine based on the rotational speed of the internal combustion engine in this way, it is possible to appropriately suppress torque fluctuations that are expected to occur in association with the switching of the drive mode.

  In one form of the control device of the present invention, the torque fluctuation suppressing means is based on the number of rotations of the cam that is rotating in the forward rotation drive mode when the drive mode of the cam before switching is the forward rotation drive mode. And adjusting the output of the internal combustion engine, and if the drive mode of the cam before switching is the swing drive mode, based on the number of swings per unit time of the cam that is swinging in the swing drive mode The output of the internal combustion engine may be adjusted (Claim 3). The rotational speed of the cam in the forward rotation drive mode and the number of cam swings per unit time in the swing drive mode are uniquely determined with respect to the rotational speed of the internal combustion engine. For example, in the case of a four-cycle internal combustion engine, if the rotational speed of the internal combustion engine is determined, the rotational speed of the cam or the number of cam swings is set to a value that is half the rotational speed of the internal combustion engine. Therefore, even by adjusting the output of the internal combustion engine based on the rotational speed of the cams and the number of cam swings, it is possible to appropriately suppress the torque fluctuation that is expected to occur with the switching of the drive mode.

  In one form of the control device of the present invention, the torque fluctuation suppressing means may adjust the output of the internal combustion engine based on a change in the intake air amount that changes when the drive mode is switched. Since the lift curve of the valve in the forward drive mode and the lift curve of the valve in the swing drive mode are not the same, the intake air amount changes when the drive mode is switched. This change in the intake air amount changes the combustion state of the internal combustion engine and affects the torque of the internal combustion engine. Therefore, the output of the internal combustion engine is adjusted based on the intake air amount when the drive mode is switched, and torque fluctuations of the internal combustion engine are appropriately suppressed.

  In this embodiment, the torque fluctuation suppressing means does not cause a response delay with respect to the rotational speed of the internal combustion engine, and the intake air amount of the internal combustion engine when the drive mode is switched. Is swung so that the difference from the intake air amount of the internal combustion engine in the forward rotation drive mode is set to the smallest value within a range that can be set in the swing drive mode. The output of the internal combustion engine may be adjusted based on the difference between the intake air amount of the engine and the intake air amount of the internal combustion engine when the cam is driven in the forward drive mode. ). By setting the intake air amount of the internal combustion engine in the oscillating drive mode in this way, the difference in the intake air amount at the time of switching the drive mode is reduced, and the torque fluctuation of the internal combustion engine that occurs when the drive mode is switched is reduced. Can be small.

  In one form of the control device of the present invention, the internal combustion engine includes an ignition plug that ignites a fuel mixture in the cylinder, and the torque fluctuation suppression means changes the ignition timing of the ignition plug to change the internal combustion engine. May be adjusted (claim 6). The torque of the internal combustion engine can be changed by changing the ignition timing. For example, the torque of the internal combustion engine can be reduced by retarding the ignition timing. Therefore, the ignition timing is changed in accordance with the torque fluctuation that is expected to occur with the switching of the drive mode to suppress the torque fluctuation of the internal combustion engine when the drive mode is switched.

  In one form of the control device of the present invention, the torque fluctuation suppressing means may adjust an output of the internal combustion engine by changing a valve operating characteristic of the valve (Claim 7). Since the amount of air introduced into the cylinder can be changed by changing the valve operating characteristics (opening / closing timing, working angle, etc.), the output of the internal combustion engine can also be adjusted. For example, the air once introduced into the cylinder can be discharged from the cylinder by retarding the valve closing timing (closing timing). Also, the amount of air introduced into the cylinder can be adjusted by changing the operating angle of the valve. Therefore, the torque fluctuation suppressing means may adjust the output of the internal combustion engine by changing the valve operating characteristic of the valve.

  One aspect of the control device of the present invention is a motor generator connected to the internal combustion engine and capable of functioning as a generator that generates electric power using the output of the internal combustion engine and an electric motor that assists the output of the internal combustion engine. And the torque fluctuation suppressing means may adjust the output of the internal combustion engine by controlling the operation of the motor generator. When the motor generator functions as a generator, the output of the internal combustion engine can be reduced. On the other hand, when the motor generator functions as an electric motor, the output of the internal combustion engine is assisted. For this reason, the torque fluctuation suppressing means may control the operation of the motor generator to suppress the torque fluctuation generated when the drive mode is switched.

  In one form of the control device of the present invention, the torque fluctuation suppression means is a lift curve of the valve that is opened and closed in the swing drive mode so that torque fluctuation of the internal combustion engine is suppressed when the drive mode is switched. Alternatively, there may be provided a lift curve adjusting means for adjusting a lift curve of at least one of the lift curves of the valves that are driven to open and close in the normal rotation drive mode. Thus, by adjusting the lift curve of the valve, it is possible to further suppress the torque fluctuation of the internal combustion engine when the drive mode is switched.

  In this embodiment, the lift curve adjusting means is driven to open and close in the swing drive mode so that the intake air amount of the internal combustion engine before and after switching of the drive mode is maintained substantially the same when the drive mode is switched. The lift curve of at least one of the lift curve of the valve or the lift curve of the valve that is driven to open and close in the forward rotation drive mode may be adjusted. Thus, by maintaining the intake air amount before and after switching of the drive mode substantially the same, the torque of the internal combustion engine can be maintained substantially the same. Therefore, it is possible to suppress torque fluctuations that are expected to occur with the switching of the drive mode.

  Further, the lift curve adjusting means does not cause a delay in the response of the cam operation to the rotational speed of the internal combustion engine in the swing drive mode, and the intake air amount of the internal combustion engine is in the swing drive mode. The lift of the valve that is driven to open and close in the swing drive mode so that the difference from the intake air amount of the internal combustion engine in the forward drive mode is set to the smallest value within the settable range in FIG. The curve may be adjusted (claim 11). Thus, by adjusting the lift curve of the valve in the swing drive mode, fluctuations in the intake air amount before and after switching of the drive modes can be suppressed, and torque fluctuations in the internal combustion engine can be suppressed.

  In one form of the control device of the present invention, the torque fluctuation suppressing means does not cause a response delay of the cam in the swing drive mode with respect to the rotational speed of the internal combustion engine when the drive mode is switched. The intake air amount of the internal combustion engine is swung so that the difference from the intake air amount of the internal combustion engine in the forward rotation drive mode is set to the smallest value within the range that can be set in the swing drive mode. The output of the internal combustion engine may be adjusted based on the difference between the intake air amount of the internal combustion engine at this time and the intake air amount of the internal combustion engine in the forward rotation drive mode (claim 12). By adjusting the output of the internal combustion engine in this way, it is possible to suppress torque fluctuations of the internal combustion engine that are expected to occur as the drive mode is switched.

  As described above, the output of the internal combustion engine can be adjusted by the ignition timing of the spark plug, the valve operating characteristics, and the motor generator. Therefore, in this embodiment, the internal combustion engine includes an ignition plug that ignites the fuel mixture in the cylinder, and the torque fluctuation suppressing means adjusts the output of the internal combustion engine by changing the ignition timing of the ignition plug. Alternatively, the torque fluctuation suppressing means may adjust the output of the internal combustion engine by changing the valve operating characteristic of the valve (claim 14). The torque fluctuation suppressing means includes a generator that is connected to the internal combustion engine and generates electric power using the output of the internal combustion engine, and a motor generator that can function as an electric motor that assists the output of the internal combustion engine. May control the operation of the motor generator to adjust the output of the internal combustion engine (claim 15).

  As described above, according to the present invention, the ignition timing of the ignition plug, the valve operating characteristics of the valve, or the output of the internal combustion engine is adjusted by the motor generator, so that the occurrence is expected with the switching of the drive mode. Suppresses torque fluctuations in internal combustion engines. Therefore, it is possible to stabilize the output of the internal combustion engine when the drive mode is switched.

[First embodiment]
FIG. 1 shows an embodiment of a four-cycle multi-cylinder reciprocating internal combustion engine (hereinafter also referred to as an engine) in which the control device of the present invention is incorporated. In FIG. 1, one cylinder 1 of the engine 100 is shown enlarged. The engine 100 is mounted on a vehicle as a driving power source, and one cylinder 1 of the engine 100 is provided with two intake valves 2 and two exhaust valves 3 as valves for opening and closing the cylinder 1. Each cylinder 1 is attached with a spark plug 4 with its electrode portion positioned substantially on the center line of each cylinder. The two intake valves 2 are driven by a common valve gear (valve mechanism) 11A, and the exhaust valve 3 is driven to open and close by another valve gear (valve mechanism) 11B. The other cylinders (not shown) are similarly driven to open and close by valve gears 11A and 11B having different intake valves and exhaust valves. The intake-side valve operating device 11A and the exhaust-side valve operating device 11B basically have the same configuration, and the intake-side valve operating device 11A will be described below.

  The intake side valve gear 11A includes an electric motor (hereinafter referred to as a motor) 12 as a drive source, a gear train 13 as a transmission mechanism for transmitting the rotational motion of the motor 12, and the rotation transmitted from the gear train 13. And a cam mechanism 14 for converting the movement into a linear opening / closing movement of the intake valve 2. As the motor 12, a DC brushless motor or the like capable of controlling the rotation speed is used. The motor 12 incorporates a position detection sensor 48 such as a resolver and a rotary encoder for detecting the rotational position. The gear train 13 transmits the rotation of the motor gear 15 attached to the output shaft (not shown) of the motor 12 to the cam drive gear 17 via the intermediate gear 16. The gear train 13 may be configured such that the motor gear 15 and the cam drive gear 17 rotate at equal speeds, or may be configured to increase or decrease the speed of the cam drive gear 17 relative to the motor gear 15. .

  As shown in FIG. 2, the cam mechanism 14 includes a cam shaft 20 that is coaxial with the cam drive gear 17 and is capable of rotating integrally therewith, and two cam shafts 20 that are provided so as to be integrally rotatable with the cam shaft 20. A cam 21 and a pair of rocker arms 23 supported so as to be swingable around a rocker arm shaft 22 corresponding to each cam 21 are provided. The cam 21 is formed as a kind of plate cam in which a nose 21a is formed by inflating a part of an arc-shaped base circle 21b coaxial with the cam shaft 20 radially outward. The profile of the cam 21 is set so that a negative curvature does not occur over the entire circumference, that is, a convex curved surface is drawn outward in the radial direction.

  Each cam 21 faces one end portion 23 a of the rocker arm 23. Each intake valve 2 is urged toward the rocker arm 23 by the compression reaction force of the valve spring 24, and the intake valve 2 is brought into close contact with the valve seat (not shown) of the intake port, thereby closing the intake port. The other end 23 b of the rocker arm 23 is in contact with the adjuster 25. When the adjuster 25 pushes up the other end portion 23 b of the rocker arm 23, the rocker arm 23 is kept in a state where its one end portion 23 a is in contact with the upper end portion of the intake valve 2.

  In the cam mechanism 14 described above, when the rotational movement of the motor 12 is transmitted to the camshaft 20 via the gear train 13, the cam 21 rotates integrally with the camshaft 20, and the nose 21a passes over the rocker arm 23. Further, the rocker arm 23 swings around the rocker arm shaft 22 within a certain range. As a result, the one end portion 23 a of the rocker arm 23 is pushed down, and the intake valve 2 is driven to open and close against the valve spring 24.

  A torque reduction mechanism 30 is provided in the valve mechanism 11A. The torque reduction mechanism 30 is provided to reduce a torque (referred to as a valve spring torque) that acts on the cam mechanism 14 based on a force that the valve spring 24 pushes the intake valve 2 back in the closing direction. The torque reduction mechanism 30 includes an anti-phase cam 31 that can rotate integrally with the cam shaft 20, and a torque applying device 32 that is disposed to face the anti-phase cam 31. The anti-phase cam 31 is formed with a cam surface having a shape based on the valve spring torque. By applying a complementary force in reverse phase to the valve spring torque from the torque adding device 32 to the cam surface, The valve spring torque acting on the mechanism 14 is reduced.

  As shown in FIG. 1, the operation of the motor 12 of the valve gears 11A and 11B is controlled by a motor control device 40 as electric motor control means. The motor control device 40 is a computer unit that includes a microprocessor and peripheral components such as a main memory necessary for its operation. The motor control device 40 controls the operation of each motor 12 according to the valve control program stored in the ROM. Although FIG. 1 shows the valve gears 11A and 11B of one cylinder 1, the motor control device 40 may be shared with the valve gears 11A and 11B of other cylinders 1. A motor control device 40 may be provided for each cylinder 1 or each valve operating device. The motor control device 40 may be provided exclusively for controlling the valve gears 11A and 11B, or may be used in combination with other applications. For example, an engine control unit (ECU) for controlling the fuel injection amount of the internal combustion engine may be used as the motor control device.

  In the motor control device 40, as information input means, an A / F sensor 41 that outputs a signal corresponding to the air-fuel ratio of the exhaust gas, and an opening of a throttle valve 47 that adjusts the intake air amount (hereinafter referred to as throttle amount). A throttle opening sensor 42 that outputs a signal corresponding to the opening of the accelerator pedal, an accelerator opening sensor 43 that outputs a signal corresponding to the opening of the accelerator pedal, an air flow meter 44 that outputs a signal corresponding to the intake air amount, A crank angle sensor 45 that outputs a signal corresponding to the angle of the crankshaft, an intake pressure sensor 46 that outputs a signal corresponding to the intake pressure of the intake manifold (intake manifold), and the like are connected. In addition, for the control of the motor 12, a value obtained from a predetermined function equation or a map may be used instead of the actual measurement values by these sensors. The output signal of the position detection sensor 48 built in the motor 12 is also input to the motor control device 40.

  Next, control of the motor 12 by the motor control device 40 will be described. Hereinafter, the control of the motor 12 for driving the intake valve 2 of one cylinder 1 will be described, but the same applies to the control of the motor 12 for driving the other intake valves 2.

  In the drive mode of the cam 21, the motor 12 is continuously rotated in one direction, and the cam 21 is moved to a position where the lift amount of the intake valve 2 becomes the maximum lift amount as shown in FIG. 3A, that is, the nose 21a of the cam 21. Is continuous in the forward rotation direction (the arrow direction in FIG. 3A) beyond the position (hereinafter, abbreviated as the maximum lift position) where it contacts the counterpart component (the rocker arm 23 in the valve gear 11A). Normal rotation drive mode, and the swing drive for reciprocating the cam 21 as shown in FIG. 3B by switching the rotation direction of the motor 12 during the lift of the intake valve 2 (while opening the cylinder 1). There is a mode. In the swing drive mode, the maximum value of the lift amount of the intake valve 2 can be changed by changing the timing for switching the rotation direction of the cam 21. For example, by switching the rotation direction of the cam 21 before the cam 21 reaches the maximum lift position, the maximum lift amount of the intake valve 2 can be adjusted to be equal to or less than the maximum lift amount. Note that the timing for switching the rotation direction of the cam 21 in the swing drive mode is appropriately set by the motor control device 40 according to the operating state of the engine 100 and the like.

  FIG. 4 shows an example of the correspondence relationship between the crank angle θ, the lift amount y of the intake valve 2, and the rotational speed (sometimes referred to as the rotational speed) Nc of the cam 21 in each of the forward drive mode and the swing drive mode. Is shown. FIG. 4A shows an example of the correspondence relationship in the forward rotation drive mode, and FIG. 4B shows an example of the correspondence relationship in the swing drive mode. The lift amount y indicates that the upper side increases in the opening direction. The cam rotation speed increases in the forward rotation direction toward the upper side of the position of the cam rotation speed Nc = 0. As shown in FIG. 4 (a), in the normal rotation drive mode, the cam 21 has a rotational speed that is half the rotational speed of the crankshaft (hereinafter referred to as the crank rotational speed) (this is referred to as the basic speed). Rotate with Nb. Hereinafter, driving the cam 21 in this way in the normal rotation driving mode is referred to as normal normal rotation driving.

  On the other hand, in the oscillating drive mode, as shown by the solid line in FIG. 4B, the cam 21 is rotated in the normal rotation direction from the state where the cam 21 is stopped (the cam rotation speed Nc is 0), and the lift The rotation speed Nc of the cam 21 is increased so that the cam rotation speed Nc reaches a predetermined speed Na at the start position Ps. Thereafter, the cam 21 is rotated forward at a predetermined speed Na for a while. The predetermined speed Na is appropriately set based on the operating state of the engine 100 so that the intake valve 2 is appropriately opened and closed in accordance with the operating state of the engine 100. When the first switching position Pa is reached, the rotational speed Nc of the cam 21 is decreased, and the rotational speed Nc of the cam 21 is set to 0 at the position Pp where the lift amount y is maximum, and the cam 21 is temporarily stopped. Thereafter, the rotational direction Nc is gradually increased by switching the rotational direction of the cam 21 to the reverse direction. Then, the cam 21 is rotated in the reverse direction at the predetermined speed Na from the second switching position Pb at which the rotational speed of the cam 21 in the reverse direction reaches the predetermined speed Na to the lift end position Pe, and the cam 21 is rotated at the lift end position Pe. Deceleration is started and then the cam 21 is stopped. 4B, the imaginary line of FIG. 4B is driven to swing so that the response of the cam 21 is not delayed with respect to the rotational speed of the engine 100, and the time area of the intake valve 2 can be set in the swing drive mode. 3 shows a correspondence relationship between the crank angle θ, the lift amount y, and the rotational speed Nc of the cam 21 when the maximum time area is set to the maximum value (hereinafter referred to as the maximum time area). At this time, the rotation direction of the cam 21 is switched at the maximum lift position. The time area is an area surrounded by a horizontal axis indicating the crank angle and a curve indicating a change in the lift amount, and is given by integrating the lift amount. Therefore, the time area varies depending on the lift curve and has a correlation with the intake air amount. As shown by the lift amount difference Δy in FIG. 4, even when the cam 21 is swung to the maximum lift position in the swing drive mode, the lift amount at that time (maximum lift amount in the swing drive mode) is the forward rotation drive. It is somewhat smaller than the maximum lift amount of the mode. This is because in the swing drive mode, the cam 21 is decelerated before reaching the position Pp where the lift amount reaches the maximum value. Hereinafter, the case where the intake valve 2 is driven to open and close with a lift curve indicated by a solid line in FIG. 4B is referred to as normal swing drive.

  FIG. 5 shows a control routine executed by the motor control device 40 for operating the cam 21 in the swing drive mode. FIG. 6 shows a control routine executed by the motor control device 40 for operating the cam 21 in the normal rotation drive mode. The control routine to perform is shown. The control routines of FIGS. 5 and 6 are repeatedly executed at predetermined intervals while the engine 100 is operating. 5 and 6 are executed in parallel.

  In the swing drive mode control routine of FIG. 5, the motor control device 40 first determines in step S11 whether the drive mode of the cam 21 is the swing drive mode. If it is not in the swing drive mode, the current control routine is terminated. On the other hand, in the swing drive mode, the process proceeds to step S12, and the motor control device 40 refers to the outputs of the sensors 41 to 46 and may be described as the engine speed (hereinafter referred to as engine speed). ) And the torque of the engine 100 (hereinafter also referred to as engine torque). The engine speed is determined with reference to, for example, the output of the crank angle sensor 45, and the engine torque is estimated based on the throttle opening detected by the throttle opening sensor 42 and the intake air amount detected by the air flow meter 44. .

  In subsequent step S13, the motor control device 40 determines whether or not switching of the drive mode from the swing drive mode to the forward drive mode is requested. The drive mode of the cam 21 is selectively used in association with the engine speed and the engine torque, for example, as shown in FIG. In FIG. 7, the swing drive mode is basically selected in the low rotation range, and the normal rotation drive mode is selected in the high rotation range, but the engine speed at the boundary between the two drive modes decreases as the engine torque increases. It is adjusted to be biased to the side. Whether or not switching of the drive mode of the cam 21 is requested is determined by storing FIG. 7 as a map in the ROM of the motor control device 40 and referring to this map. For example, the drive mode corresponding to the engine speed and the engine torque acquired in step S12 is determined with reference to the map of FIG. 7, and when the determined drive mode is the forward drive mode, that is, the acquired engine speed and engine. When the torque corresponds to the normal rotation drive region in the map of FIG. 7, it is determined that switching of the drive mode of the cam 21 is requested. In the following description, the case where the operating state at point A in FIG. 7 is switched to the operating state at point B, that is, the case where the engine torque is maintained constant before and after switching of the drive mode will be described. In addition, the case where the engine torque changes before and after switching of the drive mode will be described later when the operating state at point A in FIG. 7 is switched to the operating state at point C.

  When it is determined that switching of the drive mode of the cam 21 is not requested, the process proceeds to step S14, and the motor control device 40 operates the cam 21 by the normal swing drive described above. Thereafter, the current control routine is terminated.

  On the other hand, if it is determined that switching of the drive mode of the cam 21 is requested, the process proceeds to step S15, where the throttle opening of the engine 100 is gradually decreased and the time area of the intake valve 2 is gradually increased. As shown in FIG. 4, since the lift characteristics (particularly the maximum lift amount) given to the intake valve 2 are different in each drive mode, the intake air amount changes intermittently when the drive mode of the cam 21 is switched. As a result, the torque of engine 100 may vary. Therefore, as a preparation for switching the drive mode of the cam 21, the motor control device 40 gradually increases the time area of the intake valve 2 in the swing drive mode so as to approach the time area of the normal rotation drive mode. Further, the motor control device 40 reduces the opening of the throttle valve 46 in response to the increase in the time area and suppresses the change in the intake air amount. The time area of the intake valve 2 may be increased, for example, by increasing the maximum lift amount of the intake valve 2 or by widening the operating angle of the intake valve 2. At this time, an increase in the time area of the intake valve 2 and a decrease in the throttle amount are performed so that the intake air amount is maintained constant and torque fluctuation of the engine 100 does not occur. Details will be described later.

  In the next step S16, the motor control device 40 determines whether or not preparation for switching the drive mode is completed. Whether or not the preparation for switching is completed is determined by, for example, the time area of the intake valve 2, and when it is determined that the time area of the increased intake valve 2 has reached the maximum time area, that is, the lift curve of the intake valve 2 When it is determined that the lift curve of the imaginary line in FIG. 4B has been reached, it is determined that the preparation for switching has been completed. If it is determined that the drive mode switching preparation is not completed, the process of step S16 is repeated until the switching preparation is completed. On the other hand, if it is determined that preparation for switching the drive mode is completed, the process proceeds to step S17, and the motor control device 40 switches the drive mode of the cam 21 to the normal rotation drive mode. In addition, the motor control device 40 controls the torque of the engine 100 to be substantially constant so as to suppress the torque fluctuation of the engine 100 that is expected to occur with the switching of the drive mode substantially simultaneously with the switching of the drive mode. The ignition timing of the spark plug 4 is retarded so as to be maintained. As shown in FIG. 4, when switching from the swing drive mode to the normal rotation drive mode, the time area of the intake valve 2 increases and the intake air amount increases, so an increase in torque is expected. Therefore, the ignition timing is retarded so that the output of the engine 100 decreases.

  Torque fluctuations that are expected to occur as the drive mode is switched are affected by the rotational speed of the engine 100 (engine rotational speed) and the load factor of the engine 100 (charging efficiency). For example, since the number of times the intake valve 2 opens and closes per unit time increases as the engine speed increases, the change in the time area of the intake valve 2 has a greater influence on the torque fluctuation of the engine 100 as the engine speed increases. Further, the smaller the load factor of the engine 100, that is, the smaller the charging efficiency of the engine 100, the smaller the intake air amount before switching the drive mode. Therefore, when the load factor is small, the change in the time area of the intake valve 2 has a greater influence on the change in the intake air amount than when the load factor is large, and the torque of the engine 100 varies greatly.

Therefore, a map showing the correspondence relationship between the rotational speed of the engine 100 and the load factor of the engine 100 and the ignition timing of the spark plug 4 is stored in advance in the ROM of the motor control device 40, and the ignition timing is delayed using this map. An angular amount may be set. FIG. 8 shows an example of this map. A line A in FIG. 8 indicates a normal ignition timing when the load factor of the engine 100 is small, and a line B indicates a normal ignition timing when the load factor of the engine 100 is large. The normal ignition timing is an ignition timing set during normal operation of engine 100, and is set as appropriate according to the specifications of engine 100 and the like. Further, line C in FIG. 8 shows an ignition timing that can be set when the load factor of engine 100 is small, and torque fluctuation of engine 100 can be suppressed, and line D is set when load factor of engine 100 is large. The ignition timing which can suppress the torque fluctuation of the engine 100 is shown. 8 on the vertical axis in FIG. 8 indicates top dead center (TDC). Further, the positive on the vertical axis represents the time before the top dead center (BTDC), and the negative on the vertical axis represents the time after the top dead center (ATDC). Therefore, on the vertical axis in FIG. 8, the ignition timing is retarded as the numerical value decreases. A method for setting the ignition timing using the map of FIG. 8 will be described. For example, when the load factor of the engine 100 is small and the engine speed is N, the ignition timing of the spark plug 4 is set to a point P1 on the line C, so that the torque fluctuation of the engine 100 when the drive mode is switched Can be suppressed. Therefore, the motor control device 40 retards the ignition timing of the spark plug 4 by the difference Δθ _I between the point P2 on the line A and the point P1 on the line C when the drive mode is switched. That is, the difference Δθ _I between the point P2 and the point P1 is set as the retard amount of the ignition timing. Note that the influence of the engine speed and the load factor on the torque fluctuation at the time of switching the drive mode varies depending on the engine 100 specifications such as the displacement. Therefore, line C and line D in the map of FIG. 8 are appropriately set so that torque fluctuation does not occur when the drive mode is switched according to the specifications of engine 100 and the like.

  Returning to FIG. 5, the description of the swing drive mode control routine will be continued. In the next step S18, the motor control device 40 determines the throttle amount so that the torque of the engine 100 is maintained at the value before switching the drive mode even in the forward drive mode (hereinafter referred to as the target throttle amount at the forward drive switching). The ignition timing of the spark plug 4 is adjusted so that the torque variation of the engine 100 does not occur by adjusting the throttle amount and the ignition timing is returned to the normal ignition timing. In subsequent step S19, the motor control device 40 determines whether or not the switching of the drive mode is completed. It is determined that the switching of the drive mode is completed when, for example, the throttle amount reaches the target throttle amount during forward rotation switching and the intake manifold pressure is substantially stable. The pressure in the intake manifold is acquired with reference to an output signal of the intake pressure sensor 46, for example. If it is determined that the drive mode has been switched, the current control routine is terminated. On the other hand, if it is determined that the switching has not been completed, the process returns to step S18, and the processes of steps S18 and S19 are repeated.

  FIG. 9 shows the drive mode, the time area of the intake valve 2, the throttle amount, the ignition timing, and the engine torque time when the processing of steps S15 to S19 of the swing drive mode control routine shown in FIG. 5 is executed. An example of the change is shown. When switching of the drive mode is requested at time t0 in FIG. 9, that is, when an affirmative determination is made in step S13 in FIG. 5, the motor control device 40 increases the time area of the intake valve 2 and decreases the throttle amount. The intake air that has passed through the throttle valve 47 reaches the intake valve 2 after a predetermined time (hereinafter referred to as intake delay time) has elapsed. Therefore, as shown in FIG. 9, the intake valve 2 time is reduced with respect to the decrease in the throttle amount in consideration of the intake delay time so that the intake air amount is kept constant and the torque fluctuation of the engine 100 does not occur. Increase the area slowly.

  Thereafter, when the time area of the intake valve 2 reaches the maximum time area, the drive mode of the cam 21 is switched from the swing drive mode to the forward drive mode (time t1 in FIG. 9). At this time, as shown in FIG. 9, the time area of the intake valve 2 is increased by switching the drive mode. Therefore, the ignition timing of the spark plug 4 is suppressed so that an increase in the torque of the engine 100 due to the increase in the time area is suppressed. Is delayed. After switching to the forward rotation drive mode, the throttle amount is adjusted to the target throttle amount at the time of forward rotation switching so that the torque of the engine 100 does not fluctuate due to the adjustment of the throttle amount, and the ignition timing is the normal ignition timing. The ignition timing is adjusted so as to gradually return to. When the throttle amount reaches the target throttle amount during forward rotation switching and the intake manifold pressure is substantially stabilized (time t2 in FIG. 9), the switching of the drive mode is completed.

  Next, the normal rotation drive mode control routine of FIG. 6 will be described. In FIG. 6, the same reference numerals are used for portions common to FIG. 5, and detailed descriptions thereof are omitted.

  In the control routine of FIG. 6, the motor control device 40 first determines in step S21 whether the drive mode of the cam 21 is the normal rotation drive mode. When it is determined that the forward rotation drive mode is not set, the current control routine is terminated. On the other hand, if the forward rotation drive mode is determined, the process proceeds to step S12, and the motor control device 40 acquires the operating state of the engine 100. In subsequent step S22, the motor control device 40 determines whether or not switching of the drive mode from the normal rotation drive mode to the swing drive mode is requested. This switching of the driving mode is determined with reference to the map of FIG. 7, for example, and switching of the driving mode is required when the acquired engine speed and engine torque correspond to the swing drive region of the map of FIG. Judge that it was done. If it is determined that switching of the drive mode is not requested, the process proceeds to step S23, where the motor control device 40 operates the cam 21 by the normal forward rotation described above. Thereafter, the current control routine is terminated.

  On the other hand, if it is determined that switching of the drive mode has been requested, the process proceeds to step S24, where the motor control device 40 gradually retards the ignition timing and prevents the torque of the engine 100 from fluctuating due to this retarded ignition timing. Increase the throttle amount gradually. When switching from the forward drive mode to the swing drive mode, the time area of the intake valve 2 decreases, so the engine torque decreases. Therefore, the ignition timing is retarded in advance so as to suppress the decrease in the engine torque by the advance of the ignition timing. The advance amount to be advanced when the drive mode is switched is obtained with reference to, for example, the map of FIG. The ignition timing is retarded to an ignition timing (hereinafter referred to as a target ignition timing) such that the ignition timing returns to the normal ignition timing when the ignition timing is advanced by the advance amount when the drive mode is switched. . In the next step S25, the motor control device 40 determines whether or not preparation for switching the drive mode is completed. For example, it is determined that the preparation for switching is completed when the ignition timing is retarded to the target ignition timing. If it is determined that the preparation for switching is not completed, the process of step S25 is repeated until the preparation for switching is completed.

  On the other hand, if it is determined that preparation for switching the drive mode is completed, the process proceeds to step S26, and the motor control device 40 switches the drive mode of the cam 21 to the swing drive mode. The motor control device 40 advances the ignition timing of the spark plug 4 substantially simultaneously with the switching of the drive mode so that the torque fluctuation of the engine 100 that is expected to occur with the switching of the drive mode is suppressed. The ignition timing is returned to the normal ignition timing by this advance angle. Note that immediately after the drive mode is switched, the time area of the intake valve 2 driven in the swing drive mode is set to the maximum time area. That is, the intake valve 2 is driven to open and close with a lift curve indicated by an imaginary line in FIG. The intake valve 2 is driven to open and close in this way, and the change in the time area of the intake valve 2 when the normal drive mode is switched to the swing drive mode is minimized.

  In the next step S27, the motor control device 40 determines the throttle amount so that the torque of the engine 100 is maintained at the value before switching the drive mode even in the swing drive mode (hereinafter referred to as the target throttle amount at the swing switch). )), So that the torque of the engine 100 does not fluctuate by adjusting the throttle amount, in other words, the torque of the engine 100 is kept constant, and the time area of the intake valve 2 is normally oscillated. The time area of the intake valve 2 is adjusted so as to gradually shift to the time area at (the time area on the lift curve indicated by the solid line in FIG. 4B). In subsequent step S28, the motor control device 40 determines whether or not the switching of the drive mode has been completed. It is determined that the switching of the drive mode is completed, for example, when the throttle amount reaches the target throttle amount at the swing switching and the intake manifold pressure is substantially stable. If it is determined that the drive mode has been switched, the current control routine is terminated. On the other hand, if it is determined that the switching has not been completed, the process returns to step S27, and the processes of steps S27 and S28 are repeated.

  FIG. 10 shows the change over time of the drive mode, the time area of the intake valve 2, the throttle amount, the ignition timing, and the engine torque when the processes of steps S24 to S28 of the normal rotation drive mode control routine of FIG. 6 are executed. An example is shown. When switching of the drive mode from the forward drive mode to the swing drive mode is requested at time t10 in FIG. 10, that is, when an affirmative determination is made in step S22 in FIG. 6, the motor control device 40 determines the ignition timing of the spark plug 4. And the throttle amount is increased so that the torque of the engine 100 is maintained constant. When the ignition timing is retarded to the target ignition timing, the drive mode of the cam 21 is switched from the normal rotation drive mode to the swing drive mode (time t11 in FIG. 10). At that time, the time area of the intake valve 2 is reduced as shown in FIG. 10, and therefore the ignition timing of the spark plug 4 is advanced so that the torque fluctuation of the engine 100 due to the reduction of the time area is suppressed. Further, the ignition timing is returned to the normal ignition timing by the advance angle at time t11. Note that, as described above, the intake valve 2 immediately after the drive mode is switched is opened and closed by a lift curve indicated by an imaginary line in FIG.

  Thereafter, while gradually increasing the throttle amount to the target throttle amount at the time of swing switching, the time area of the intake valve 2 is the time area in the normal swing drive so that the torque of the engine 100 does not fluctuate due to the increase in the throttle amount. The time area of the intake valve 2 is reduced so as to shift to. Also in this case, taking into account the intake delay time, the time area of the intake valve 2 is gradually reduced as the throttle amount increases. The drive mode switching is completed when the throttle amount reaches the target throttle amount during swing switching and the intake manifold pressure is substantially stabilized (time t12 in FIG. 10).

  As described above, in the control routines of FIGS. 5 and 6, when the drive mode of the cam 21 is switched, the ignition is performed so as to suppress the torque fluctuation of the engine 100 that is expected to occur with the switching of the drive mode. The ignition timing of the plug 4 is adjusted. Therefore, the torque of engine 100 can be maintained substantially constant. The control of the ignition plug 4 and the throttle valve 47 by the motor control device 40 is performed when an instruction relating to the adjustment of the ignition timing and an instruction relating to the adjustment of the throttle amount are issued when there is another computer for controlling the ignition timing and the throttle amount. What is necessary is just to implement | achieve by giving with respect to the computer from the control apparatus 40. FIG.

  The retard amount of the ignition timing retarded when the drive mode is switched may be set according to the number of rotations of the cam 21 in the normal forward drive or the number of swings of the cam 21 per unit time in the normal swing drive. Since the rotational speed of the cam 21 and the number of swings of the cam 21 are respectively set according to the engine rotational speed, the retard amount of the ignition timing can be set based on these. Further, as described above, the torque fluctuation that is expected to occur with the switching of the drive mode is caused by the fluctuation of the intake air amount when the drive mode is switched. Therefore, the retard amount of the ignition timing may be set according to the difference in the intake air amount when the drive mode is switched. When the torque fluctuation that is expected to occur with the switching of the drive mode can be sufficiently suppressed by the retard of the ignition timing, the time area of the intake valve 2 that is driven to open and close in the swing drive mode when switching the drive mode is maximized It is not necessary to set the time area. Thus, the time required for switching the drive mode can be shortened by not setting the time area of the intake valve 2 to the maximum time area.

  The motor control device 40 performs the processing of step S17 in FIG. 5 and step S26 in FIG. 6 to adjust the ignition timing to suppress torque fluctuations that are expected to occur as the drive mode is switched. It functions as torque fluctuation suppressing means of the invention. In addition, the motor control device 40 performs the processing of steps S15 and S16 in FIG. 5 and the processing of steps S24 and S25 in FIG. 6 and adjusts the lift curve so that the torque fluctuation of the engine 100 is suppressed. It functions as a lift curve adjusting means of the present invention.

[Second form]
Next, a second embodiment of the present invention will be described with reference to FIGS. The output of the engine 100 can also be adjusted by changing the valve operating characteristics of the intake valve 2. Therefore, in this embodiment, the motor control device 40 of FIG. 1 executes the control routine of FIG. 11 in place of the swing drive mode control routine of FIG. 5, and changes the closing timing of the intake valve 2 to change the torque of the engine 100. Suppress fluctuations. 11 that are the same as those in FIG. 5 are denoted by the same reference numerals, and detailed descriptions thereof are omitted.

  In the control routine of FIG. 11, the motor control device 40 performs the same process as in FIG. 5 until step S16. When it is determined in step S16 that the preparation for switching the drive mode is completed, the process proceeds to step S31, and the motor control device 40 switches the drive mode of the cam 21 to the normal rotation drive mode. Further, the motor control device 40 retards the closing timing of the intake valve 2 at the same time as the switching of the driving mode so that the torque fluctuation of the engine 100 that is expected to occur in association with the switching of the driving mode is suppressed. When switching from the oscillating drive mode to the forward rotation drive mode, the time area of the intake valve 2 increases, so an increase in torque is expected. Therefore, the closing time of the intake valve 2 is retarded so that the air flows backward from the cylinder 1 to the intake manifold, in other words, the air blows back from the cylinder 1 to the intake manifold, thereby reducing the amount of air in the cylinder 1. Decrease. Since the decrease in the air amount reduces the output of the engine 100, an increase in torque due to an increase in the time area of the intake valve 2 is suppressed, and a torque fluctuation of the engine 100 is suppressed.

As described above, the torque fluctuation that is expected to occur when the drive mode is switched is affected by the rotational speed of the engine 100 and the load factor. Therefore, a map in which the rotational speed of the engine 100, the load factor of the engine 100 and the closing timing of the intake valve 2 are associated with each other is stored in advance in the ROM of the motor control device 40, and the retard amount of the closing timing is utilized using this map. May be set. FIG. 12 shows an example of this map. A line E in FIG. 12 indicates the closing timing of the intake valve 2 when the load factor of the engine 100 is large and the cam 21 is normally driven in the normal rotation drive mode. A line F in FIG. The closing timing of the intake valve 2 when the load factor is small and the cam 21 is normally normally driven in the normal rotation drive mode is shown. Also, the line G in FIG. 12 indicates the closing time when the torque variation of the engine 100 can be suppressed by setting when the load factor of the engine 100 is large, and the line H is set when the load factor of the engine 100 is small. The closing time when the torque fluctuation of the engine 100 can be suppressed is shown. In the vertical axis of FIG. 12, the positive direction indicates an advance angle, and the negative direction indicates a retard angle. A method for setting the closing time when switching the drive mode using the map of FIG. 12 will be described. For example, when the load factor of the engine 100 is large and the engine speed is N, the closing timing of the intake valve 2 is set to a point P3 on the line G, so that the torque fluctuation of the engine 100 when the drive mode is switched Can be suppressed. Therefore, the motor control device 40 retards the valve closing timing of the intake valve 2 by the difference Δθ _V between the point P4 on the line E and the point P3 on the line G when the drive mode is switched. The torque fluctuation that occurs when the drive mode is switched varies depending on the specifications of the engine 100. Therefore, line G and line H in FIG. 12 are appropriately set so that torque fluctuations that are expected to occur in association with switching of the drive mode can be suppressed according to the specifications of engine 100 and the like.

  Returning to FIG. 11, the description of the swing drive mode control routine will be continued. After switching the drive mode to the forward rotation drive mode, in the next step S32, the motor control device 40 gradually decreases the throttle amount to the target throttle amount at the time of forward rotation switching, and the torque of the engine 100 is reduced by this decrease in the throttle amount. The closing timing of the intake valve 2 is advanced so that the fluctuation does not occur and the closing timing of the intake valve 2 shifts to the closing timing in normal normal rotation driving. In subsequent step S19, the motor control device 40 determines whether or not the switching of the drive mode is completed. If it is determined that the drive mode has been switched, the current control routine is terminated. On the other hand, if it is determined that the switching of the drive mode has not been completed, the process returns to step S32, and the processes of steps S32 and S19 are repeated.

  FIG. 13 shows the drive mode, the time area of the intake valve 2, the throttle amount, the intake valve when the processing of steps S15, S16, S31, S32 and S19 of the swing drive mode control routine shown in FIG. 11 is executed. 2 shows an example of the closing timing of 2 and the time variation of the engine torque. When switching of the drive mode is requested at time t20 in FIG. 13, that is, when an affirmative determination is made in step S13 in FIG. 11, the motor control device 40 increases the time area of the intake valve 2 and the torque of the engine 100 is substantially reduced. Decrease the throttle amount to keep it constant. As shown in FIG. 13, the time area of the intake valve 2 is gradually increased with respect to the decrease in the throttle amount in consideration of the intake delay time. The time area of the intake valve 2 is increased by increasing the maximum value of the operating angle and lift amount of the intake valve 2. Therefore, the valve closing timing of the intake valve 2 is gradually retarded from time t20 as the operating angle increases.

  Thereafter, when the time area of the intake valve 2 reaches the maximum time area at time t21, the drive mode of the cam 21 is switched from the swing drive mode to the forward drive mode. At this time, since the time area of the intake valve 2 suddenly increases as shown in FIG. 13, the closing timing of the intake valve 2 is retarded in order to keep the torque of the engine 100 constant. After switching to the forward rotation drive mode, the throttle amount is adjusted to the target throttle amount at the time of forward rotation switching so that the torque of the engine 100 does not fluctuate due to the adjustment of the throttle amount, and the closing timing of the intake valve 2 is normal. The closing timing of the intake valve 2 is adjusted so as to shift to the closing timing in the forward rotation drive. When the throttle amount reaches the target throttle amount during forward rotation switching and the intake manifold pressure is substantially stabilized (time t22 in FIG. 13), the switching of the drive mode is completed.

  As described above, adjusting the closing timing of the intake valve 2 can also suppress the torque fluctuation of the engine 100 that is expected to occur with the switching of the drive mode.

  In the above, switching from the swing drive mode to the forward drive mode has been described as an example. However, when switching from the forward drive mode to the swing drive mode, the reverse control is performed to switch the drive mode. Torque fluctuations in engine 100 that are expected to occur are suppressed. When switching from the forward drive mode to the oscillating drive mode, the time area of the intake valve 2 is abruptly reduced when the drive mode is switched. Adjust the closing time. As such a closing time, for example, a closing time is set such that air does not blow back from the cylinder 1 to the intake manifold and the cylinder 1 is sufficiently filled with air. Since the closing time set in this way increases the output of the engine 100, the torque fluctuation of the engine 100 due to the reduction of the time area can be suppressed. Note that such closing timing of the intake valve 2 is obtained in advance through experiments in various operating states, and stored in the ROM of the motor control device 40 as a map.

  The means for adjusting the air amount in the cylinder 1 is not limited to the closing timing of the intake valve 2. For example, the output of the engine 100 can be adjusted by adjusting the amount of air introduced into the cylinder 1 by retarding the closing timing of the exhaust valve 3. For this reason, the valve operating characteristics of the exhaust valve 3 may be adjusted to suppress torque fluctuations that are expected to occur when the drive mode is switched. Further, the valve operating characteristic that is adjusted to suppress the torque fluctuation is not limited to the closing timing. For example, the operating angle of the intake valve 2 may be adjusted so that air flows back from the cylinder 1 to the intake manifold.

[Third embodiment]
A third embodiment of the present invention will be described with reference to FIGS. FIG. 14 is a diagram showing a configuration of an engine 100 in which a control device according to the third embodiment of the present invention is incorporated. The engine 100 also includes valve gears 11A and 11B as in the first embodiment. As shown in FIG. 14, in this embodiment, a motor generator (hereinafter abbreviated as MG) 200 is connected to engine 100. The MG 200 is connected to the engine 100 so that it can generate electric power using the output of the engine 100 and can output power to the engine 100 to assist the output of the engine 100. Since the connection method between engine 100 and MG 200 may be the same as that used in a well-known hybrid vehicle or the like, detailed description thereof is omitted here. The MG 200 functions as an electric motor and a generator, and switching between these is controlled by the motor control device 40. For example, when the torque of the engine 100 (engine torque) is reduced, the motor control device 40 causes the MG 200 to function as an electric motor and assists the engine 100. On the other hand, when the voltage of the battery 201 connected to the MG 200 is reduced, the battery 201 is charged by causing the MG 200 to function as a generator. In this case, since MG 200 is driven by engine 100, the engine torque can be reduced. Therefore, when MG 200 is connected to engine 100 in this way, torque fluctuations that are expected to occur when the drive mode is switched may be suppressed by MG 200.

  FIG. 15 shows a swing drive mode control routine executed by the motor control device 40 of FIG. 14 at a predetermined cycle while the engine 100 is operating. 15 that are the same as those in FIG. 5 are denoted by the same reference numerals, and detailed descriptions thereof are omitted.

  In the control routine of FIG. 15, the motor control device 40 performs the same process as in FIG. 5 until step S16. When it is determined in step S16 that the preparation for switching the drive mode is completed, the process proceeds to step S41, and the motor control device 40 switches the drive mode from the swing drive mode to the forward drive mode. In addition, motor control device 40 operates MG 200 substantially simultaneously with the switching of the driving mode so that torque fluctuations of engine 100 that are expected to occur in association with the switching of the driving mode are suppressed. When switching from the swing drive mode to the normal rotation drive mode, an increase in engine torque is expected, so the motor control device 40 causes the MG 200 to function as a generator to reduce the engine torque. As described above, the torque fluctuation of engine 100 that is expected to occur when the drive mode is switched is affected by the engine speed and the load factor. Therefore, the engine torque (hereinafter referred to as adjustment torque) to be reduced by the MG 200 when the drive mode is switched is mapped in advance in the ROM of the motor control device 40, for example, the relationship between the adjustment torque and the rotation speed and load factor of the engine 100. And the value of the adjustment torque is set using this map.

  In the next step S42, the motor control device 40 gradually decreases the throttle amount to the target throttle amount at the time of forward rotation switching, so that torque fluctuation of the engine 100 does not occur due to the decrease in the throttle amount, and the torque ( Hereinafter, the MG torque is adjusted so that the value is abbreviated as MG torque) to the value before switching the drive mode. In subsequent step S19, the motor control device 40 determines whether or not the switching of the drive mode is completed. If it is determined that the drive mode has been switched, the current control routine is terminated. On the other hand, if it is determined that the switching has not been completed, the process returns to step S42, and the processes of steps S42 and S19 are repeated.

  FIG. 16 shows the drive mode, the time area of the intake valve 2, the throttle amount, and the MG torque when the processes of steps S15, S16, S41, S42 and S19 of the swing drive mode control routine shown in FIG. 15 are executed. And an example of the time change of the engine torque. When switching of the drive mode is requested at time t30 in FIG. 16, the motor control device 40 starts increasing the time area of the intake valve 2 and adjusts the throttle amount so that the torque of the engine 100 is maintained substantially constant. Decrease.

  Thereafter, when the time area of the intake valve 2 reaches the maximum time area at time t31, the drive mode of the cam 21 is switched from the swing drive mode to the forward drive mode. At this time, the time area of the intake valve 2 suddenly increases and the engine torque increases, but the increase in the engine torque is suppressed, and the MG torque is adjusted so as to keep the engine torque constant. Specifically, MG 200 is caused to function as a generator, and the engine torque is reduced. After switching to the forward rotation drive mode, before adjusting the throttle amount to the target throttle amount at the time of forward rotation switching so that the torque of the engine 100 does not fluctuate due to the adjustment of the throttle amount, and before the MG torque switches the drive mode The output of MG 200 is adjusted so as to return to the value of. When the throttle amount reaches the target throttle amount during forward rotation switching and the intake manifold pressure is substantially stabilized (time t32 in FIG. 16), the drive mode switching is completed.

  As described above, when MG 200 is connected to engine 100, the torque fluctuation of engine 100 that is expected to occur when the drive mode is switched can also be suppressed by adjusting the output of MG 200. In the above description, the case of switching from the swing drive mode to the forward drive mode has been described. However, the torque fluctuation of the engine 100 that is expected to occur with the switch from the forward drive mode to the swing drive mode is also described. It can be suppressed by adjusting the output of MG200. At the time of switching from the forward drive mode to the swing drive mode, the time area of the intake valve 2 decreases, so the torque of the engine 100 decreases. Therefore, in this case, the MG 200 is caused to function as an electric motor, and the torque of the engine 100 is assisted so that the torque of the engine 100 is maintained constant. The control of the MG 200 by the motor control device 40 may be realized by giving an instruction relating to the output adjustment of the MG 200 from the motor control device 40 to the computer when there is another computer that controls the operation of the MG 200.

  The present invention is not limited to the form described above, and may be implemented in various forms. For example, in the first to third embodiments described above, the control in the case where the torque of the engine 100 is constant before and after the switching of the driving mode is shown, but the switching of the driving mode is performed when the output of the engine 100 is changed. That is, it may be performed when the torque is changed. For example, when the engine 100 is accelerated, the engine torque and the engine speed are increased, so there is a possibility that switching from the swing drive mode to the forward drive mode may be required. Further, when the engine 100 is decelerated, the engine torque and the engine speed are decreased, and there is a possibility that switching from the normal rotation drive mode to the swing drive mode may be required. Therefore, an outline of control in the case where the engine torque is increased, for example, when the engine 100 is accelerated, is shown below.

  For example, when the operating state of the engine 100 is shifted from the point A to the point C in FIG. 7, the drive mode is switched from the swing drive mode to the forward drive mode while the engine torque is gradually increased. FIG. 17 shows an example of the drive mode when switching the drive mode of the cam 21 while gradually increasing the torque of the engine 100 in this way, the time area of the intake valve 2, the throttle amount, the ignition timing, and the engine torque over time. Is shown. As a comparative example, FIG. 17 shows an example of changes over time in the throttle amount, ignition timing, and engine torque when the torque is kept constant before and after the drive mode switching.

  When switching of the drive mode from the swing drive mode to the forward drive mode is requested at time t41 in FIG. 17, the motor control device 40 gradually increases the time area of the intake valve 2 and decreases the throttle amount. At this time, the motor control device 40 reduces the throttle amount smaller than that of the comparative example so that the torque of the engine 100 smoothly shifts to the value of the point C in FIG. Thus, the engine torque is gradually increased by reducing the amount of change in the throttle amount.

  Thereafter, when the time area of the intake valve 2 reaches the maximum time area, the drive mode of the cam 21 is switched from the swing drive mode to the forward drive mode (time t41 in FIG. 17). At substantially the same time as the switching of the driving mode, the ignition timing of the spark plug 4 is retarded so that the torque fluctuation of the engine 100 that occurs in association with the switching of the driving mode is suppressed. The retard amount of the ignition timing at this time is set smaller than that in the comparative example so that the torque of the engine 100 smoothly transitions to the torque at point C in FIG. 7 as shown in FIG. Further, the retard amount at this time is set so that the torque of the engine 100 does not increase suddenly at time t41, for example, so that the torque of the engine 100 increases smoothly from point A to point C in FIG. .

  After the drive mode is switched, the retarded ignition timing is gradually returned to the normal ignition timing, and the throttle amount is adjusted so that the torque of the engine 100 does not fluctuate due to the change in the ignition timing. When the ignition timing of the spark plug 4 is returned to the normal ignition timing at time t42 in FIG. 17, the throttle amount is gradually increased so that the torque of the engine 100 smoothly transitions to the torque at point C in FIG. .

  When the drive mode is switched from the normal rotation drive mode to the swing drive mode while reducing the torque of the engine 100, such as when the engine 100 is decelerated, the time area of the intake valve 2 is reduced. The ignition timing of the spark plug 4 is adjusted so that the torque of the spark plug 4 does not drop suddenly. As described above, when switching from the normal rotation drive mode to the swing drive mode, the ignition timing is retarded to the target ignition timing by the time of switching, and the ignition timing is advanced when the drive mode is switched. Torque fluctuations are suppressed. When the engine 100 is decelerated, the retard amount of the ignition timing that is retarded by the time of switching is set smaller than when the engine 100 torque is kept constant in order to smoothly reduce the torque of the engine 100. . After the drive mode is switched, the time area of the intake valve 2 is shifted from the maximum time area to the time area set in the normal swing drive mode. Further, the amount of throttle is increased so that the torque fluctuation of engine 100 due to the reduction of the time area is suppressed, and the torque of engine 100 decreases smoothly.

  As described above, the drive mode can be switched to the cam 21 while smoothly increasing or decreasing the torque of the engine 100 by adjusting the ignition timing and the throttle amount at the time of switching the drive mode as described above. Even when the drive mode is switched while changing the engine torque in this way, in addition to the ignition timing of the spark plug 4, the valve operating characteristics of the intake valve 2 or the operation of the MG 200 is controlled to switch the drive mode. Torque fluctuations that are expected to occur may be suppressed.

  The engine to which the present invention is applied is not limited to the case where the valve gear 11A is provided in each cylinder. For example, the present invention may be applied to an engine in which the valve gear 11A is provided for each cylinder group constituted by a plurality of cylinders whose valve opening periods do not overlap. FIG. 18 shows a cross-sectional view of the main part of such an engine 100. In FIG. 18, parts that are the same as those in FIG. 1 are given the same reference numerals, and descriptions thereof are omitted. The engine 100 of FIG. 18 is a so-called in-line four-cylinder engine in which four cylinders 1 are arranged in a row. As shown in FIG. 18, the cylinders 1 are assigned numbers # 1 to # 4 to distinguish the cylinders 1 from each other. In the engine 100 of FIG. 18, the opening timings of the # 1 cylinder 1 and the # 4 cylinder 1 do not overlap, and the opening periods of the # 2 cylinder 1 and the # 3 cylinder 1 do not overlap. The valve opening time is set. Therefore, the valve gears 11A are provided in the first cylinder group constituted by the cylinders # 1 and # 4 and the second cylinder group constituted by the cylinders # 2 and # 3, respectively.

  As shown in FIG. 18, the valve gear 11A of the first cylinder group includes a motor 12a, a first cam mechanism 14a in which the rotation of the motor 12a is transmitted through the gear train 13a, and a torque reduction mechanism 30a. It has. The gear train 13 a includes a motor gear 15 that rotates integrally with the output shaft of the motor 12 a, and a cam drive gear 17 that is attached to one end of the cam shaft 50 so as to be integrally rotatable and meshes with the motor gear 15. The first cam mechanism 14a includes a cam shaft 50. The cam shaft 50 includes two cams 51 for opening and closing the intake valve 2 of the # 1 cylinder 1 and the intake valve 2 of the cylinder 4 of # 4. Two cams 52 for opening and closing are provided so as to rotate together with the cam shaft 50. The cam 51 and the cam 52 are provided on the cam shaft 50 so that the apexes of the nose are displaced from each other by 180 ° in the circumferential direction. The cam shaft 50 has a connecting structure in which a first shaft portion 50a provided with a cam 51 and a second shaft portion 50b provided with a cam 52 are combined. As shown in FIG. 18, the first shaft portion 50a is integrally and integrally formed with a connecting shaft portion 50c that passes above the # 2 cylinder and the # 3 cylinder and extends to the # 4 cylinder. . The ends of the connecting shaft portion 50c are coaxially fitted to the second shaft portion 50b, whereby the shaft portions 50a and 50b are coaxially connected.

  The valve operating apparatus 11A for the second cylinder group includes a motor 12b, a second cam mechanism 14b in which the rotation of the motor 12b is transmitted via the gear train 13b, and a torque reduction mechanism 30b. The second cam mechanism 14b is provided with a cam shaft 53. The cam shaft 53 has two cams 54 for opening and closing the intake valve 2 of the cylinder # 2 and the intake valve 2 of the cylinder 1 of # 3. Two cams 55 for opening and closing the cam shaft 53 are provided so as to rotate integrally with the cam shaft 53. The cam 54 and the cam 55 are respectively provided on the cam shaft 53 so that the apexes of the nose are shifted from each other by 180 ° in the circumferential direction. As shown in FIG. 18, the cam shaft 53 is formed in a hollow shaft shape having a through hole 53a extending in the axial direction, and a cam 54 and a cam 55 are provided on the outer periphery thereof. A connecting shaft portion 50c of the cam shaft 50 is rotatably inserted into the through hole 53a of the cam shaft 53. Thereby, the cam shaft 53 is coaxially disposed on the outer periphery of the cam shaft 50 in a freely rotatable state. The outer diameter of the cam shaft 53 is the same as the outer diameter of the first shaft portion 50a and the second shaft portion 50b of the cam shaft 50.

  As shown in FIG. 18, a valve lifter 60 is attached to the upper end of the intake valve 2 provided in each cylinder 1 so as to be able to reciprocate integrally with the intake valve 2. Each of the cams 51, 52, 54, and 55 drives the intake valve 2 to open and close by pushing the valve lifter 60 with the nose of each cam.

  In such an engine 100, the cylinder opening periods of the cylinder groups do not overlap with each other. Therefore, even if the valve characteristic of the valve of one cylinder is changed, this change affects the valve characteristic of the valve of the other cylinder. Not give. Therefore, the drive mode of each cam can be switched between the normal rotation drive mode and the swing drive mode. Therefore, the present invention is applied to such an engine 100 to suppress torque fluctuation when switching the cam drive mode.

  In the above-described embodiment, the torque variation of the engine 100 is suppressed by the ignition timing of the spark plug 4, the valve operating characteristics of the intake valve 2, and the MG 200, but these are appropriately combined to suppress the torque variation at the time of switching the drive mode. May be. For example, the torque variation of the engine 100 when the drive mode is switched may be suppressed by changing both the ignition timing of the spark plug 4 and the valve operating characteristics of the intake valve 2.

  In the embodiment described above, the time area of the intake valve 2 in the swing drive mode, that is, the lift curve of the intake valve 2 is changed to reduce the time area difference at the time of switching the drive mode to suppress the torque fluctuation of the engine 100. However, the time area difference at the time of drive mode switching may be reduced by changing the time area (lift curve) of the intake valve 2 in the forward rotation drive mode. For example, the time area of the intake valve 2 can be reduced by increasing the rotational speed of the cam 21 in the normal rotation drive mode only during the period in which the nose 21a is in contact with the counterpart component. Further, both the lift curve of the intake valve 2 in the forward drive mode and the lift curve of the intake valve 2 in the swing drive mode are adjusted, and the time area in each drive mode, that is, the intake air amount, as shown in FIG. May be substantially matched. Thus, by adjusting the lift curve in each drive mode and maintaining the intake air amount at the time of switching the drive mode substantially the same, the torque fluctuation of the engine 100 at the time of drive mode switching can be further suppressed.

  The swing range of the cam 21 in the swing drive mode is an appropriate period so that both sides of the cam 21 sandwiching the apex of the nose 21a (hereinafter abbreviated as the nose apex) are used for driving the intake valve 2. It may be changed every time. For example, the cam surface 21c on one side (see FIG. 3B) sandwiching the nose apex of the cam 21 and the cam surface 21d on the other side (see FIG. 3B) alternately alternate parts, For example, in FIG. 3B, the swing range may be switched at appropriate intervals so as to come into contact with the rocker arm 23. By switching the swing range in this way, the wear of the cam 21 can be made to progress evenly, and the bias of lubrication between the cam 21 and the counterpart component can be suppressed.

  The valve gear to which the present invention is applied is not limited to the valve gear described above. For example, the output shaft of the motor and the cam shaft may be directly connected. The torque reduction mechanism is not necessarily provided in the embodiment of the present invention. When the torque reduction mechanism is provided, the antiphase cam is not necessarily provided on the cam shaft. For example, an antiphase cam may be provided on the intermediate shaft of the gear train. However, the rotational speed of the antiphase cam needs to be set to an integral multiple of the rotational speed of the cam shaft.

The perspective view which shows the principal part of the engine in which the control apparatus of this invention was integrated. The figure which shows the detail of the cam mechanism of FIG. FIGS. 4A and 4B are diagrams showing cam operation in each drive mode, where FIG. 5A shows the cam operation in the forward rotation drive mode, and FIG. FIG. 5 is a diagram showing a correspondence relationship between a crank angle, a lift amount of an intake valve, and a cam rotation speed in each drive mode, where (a) shows a correspondence relationship in a normal rotation drive mode, and (b) shows a correspondence in a swing drive mode. Show the relationship. The flowchart which shows the rocking | fluctuation drive mode control routine which the motor control apparatus of FIG. 1 performs. The flowchart which shows the normal rotation drive mode control routine which the motor control apparatus of FIG. 1 performs. The figure which shows the application area | region of each drive mode of a cam. The figure which shows the correspondence of the rotation speed of an engine, an engine load factor, and the ignition timing of a spark plug. When the drive mode is switched from the swing drive mode to the forward drive mode in the swing drive mode control routine of FIG. 5, the time change of the drive mode, the time area of the intake valve, the throttle amount, the ignition timing, and the engine torque is changed. The figure which shows an example. Changes in the drive mode, the intake valve time area, the throttle amount, the ignition timing, and the engine torque over time when the drive mode is switched from the forward drive mode to the swing drive mode in the forward drive mode control routine of FIG. The figure which shows an example. The flowchart which shows the rocking | fluctuation drive mode control routine which a motor control apparatus performs in a 2nd form. The figure which shows the correspondence of the rotation speed of an engine, an engine load factor, and the closing timing of an intake valve. When the drive mode is switched from the swing drive mode to the forward drive mode in the swing drive mode control routine of FIG. 11, the drive mode, intake valve time area, throttle amount, intake valve closing timing, and engine torque The figure which shows an example of a time change. The figure which shows the structure of the engine in which the control apparatus which concerns on a 3rd form is integrated. The flowchart which shows the rocking | fluctuation drive mode control routine which the motor control apparatus of FIG. 14 performs. When the drive mode is switched from the oscillating drive mode to the normal rotation drive mode in the oscillating drive mode control routine of FIG. 15, the time changes of the drive mode, the intake valve time area, the throttle amount, the MG torque, and the engine torque are changed. The figure which shows an example. An example of drive mode, intake valve time area, throttle amount, spark plug ignition timing, and engine torque time change when switching the drive mode from the swing drive mode to the forward drive mode while increasing the engine torque FIG. Sectional drawing which shows the engine provided with the other valve operating apparatus which can apply this invention. The figure which shows the lift curve of the intake valve in each drive mode when adjusting the lift curve of the intake valve in both drive modes, respectively, and making the time area of the intake valve in both drive modes substantially correspond.

Explanation of symbols

1 Cylinder 2 Intake valve 3 Exhaust valve 4 Spark plug 11A, 11B Valve train (valve mechanism)
12 Motor (electric motor)
21 cam 40 motor control device (motor control means, torque fluctuation suppression means, lift curve adjustment means)
100 engine (internal combustion engine)
200 Motor generator

Claims (15)

A valve operating mechanism that converts the rotational motion of the electric motor into a linear motion by a cam and drives the valve of the cylinder to open and close by the linear motion, a normal rotation driving mode in which the cam is continuously rotated in one direction, and a lift of the valve In the control device applied to the internal combustion engine, the motor control means capable of driving the motor in each of the swing drive modes for switching the rotation direction of the cam.
The motor control means controls the internal combustion engine to suppress torque fluctuations of the internal combustion engine that are expected to occur in association with switching of the drive mode when switching between the swing drive mode and the forward drive mode. A control apparatus for an internal combustion engine, comprising torque fluctuation suppressing means for adjusting an output.   2. The control device for an internal combustion engine according to claim 1, wherein the torque fluctuation suppressing unit adjusts an output of the internal combustion engine based on a rotation speed of the internal combustion engine when the drive mode is switched.   The torque fluctuation suppressing means adjusts the output of the internal combustion engine based on the rotational speed of the cam that is rotating in the normal rotation drive mode when the cam drive mode before switching is the normal rotation drive mode, When the drive mode of the cam before switching is the swing drive mode, the output of the internal combustion engine is adjusted based on the number of swings per unit time of the cam that is swinging in the swing drive mode. The control apparatus for an internal combustion engine according to claim 1, wherein the control apparatus is an internal combustion engine.   2. The control device for an internal combustion engine according to claim 1, wherein the torque fluctuation suppression unit adjusts an output of the internal combustion engine based on a change in an intake air amount that changes when the drive mode is switched.   The torque fluctuation suppressing means does not cause a response delay with respect to the rotational speed of the internal combustion engine and causes the intake air amount of the internal combustion engine to fluctuate when the drive mode is switched. The intake air of the internal combustion engine at this time is swung so that the difference from the intake air amount of the internal combustion engine in the forward rotation drive mode is set to the smallest value within a settable range in the drive mode. 5. The output of the internal combustion engine is adjusted based on a difference between the intake air amount of the internal combustion engine when the cam is driven in the forward rotation drive mode. Control device for internal combustion engine. The internal combustion engine includes a spark plug that ignites a fuel mixture in the cylinder,
The control device for an internal combustion engine according to any one of claims 1 to 5, wherein the torque fluctuation suppressing means adjusts an output of the internal combustion engine by changing an ignition timing of the spark plug.   The control device for an internal combustion engine according to any one of claims 1 to 5, wherein the torque fluctuation suppressing means adjusts an output of the internal combustion engine by changing a valve operating characteristic of the valve. A generator that is connected to the internal combustion engine and generates electric power using the output of the internal combustion engine, and a motor generator capable of functioning as an electric motor that assists the output of the internal combustion engine;
The control device for an internal combustion engine according to any one of claims 1 to 5, wherein the torque fluctuation suppressing unit adjusts an output of the internal combustion engine by controlling an operation of the motor generator.   The torque fluctuation suppression means is opened / closed in the lift curve of the valve driven in the swing drive mode or in the forward drive mode so that torque fluctuation of the internal combustion engine is suppressed when the drive mode is switched. The control apparatus for an internal combustion engine according to claim 1, further comprising lift curve adjusting means for adjusting a lift curve of at least one of the lift curves of the valve to be operated.   The lift curve adjusting means lifts the valve that is opened and closed in the swing drive mode so that the intake air amount of the internal combustion engine before and after the drive mode is switched is maintained substantially the same when the drive mode is switched. The control apparatus for an internal combustion engine according to claim 9, wherein a lift curve of at least one of a curve or a lift curve of the valve that is driven to open and close in the normal rotation drive mode is adjusted.   The lift curve adjusting means does not cause a delay in response of the cam operation with respect to the rotational speed of the internal combustion engine in the swing drive mode, and the intake air amount of the internal combustion engine is set in the swing drive mode. A lift curve of the valve that is driven to open and close in the swinging drive mode is set so that the difference from the intake air amount of the internal combustion engine in the forward rotation drive mode is the smallest within a possible range. The control device for an internal combustion engine according to claim 9, wherein adjustment is performed.   The torque fluctuation suppressing means does not cause a response delay with respect to the rotational speed of the internal combustion engine and causes the intake air amount of the internal combustion engine to fluctuate when the drive mode is switched. The intake air of the internal combustion engine at this time is swung so that the difference from the intake air amount of the internal combustion engine in the forward rotation drive mode is set to the smallest value within a settable range in the drive mode. 10. The control device for an internal combustion engine according to claim 9, wherein the output of the internal combustion engine is adjusted based on a difference between the amount and an intake air amount of the internal combustion engine in the normal rotation drive mode. The internal combustion engine includes a spark plug that ignites a fuel mixture in the cylinder,
The control device for an internal combustion engine according to claim 12, wherein the torque fluctuation suppressing means adjusts an output of the internal combustion engine by changing an ignition timing of the spark plug.   The control device for an internal combustion engine according to claim 12, wherein the torque fluctuation suppressing means adjusts an output of the internal combustion engine by changing a valve operating characteristic of the valve. A generator that is connected to the internal combustion engine and generates electric power using the output of the internal combustion engine, and a motor generator capable of functioning as an electric motor that assists the output of the internal combustion engine;
The control apparatus for an internal combustion engine according to claim 12, wherein the torque fluctuation suppressing means adjusts an output of the internal combustion engine by controlling an operation of the motor generator.

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