JP2008280933A - Internal combustion engine control device and internal combustion engine control system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an internal combustion engine control device compatibly establishing both of reduction of a sense of incongruity given to an operator who did off-operation for commanding stop of the internal combustion engine, and increase of assuredness of locking a rotor after the off-operation. <P>SOLUTION: An engine ECU as an advancing and retarding angle position control means executes lock control (step S50) controlling hydraulic control valve to relatively rotate the rotor toward a lock position (most retarded position) from a point of time when the vehicle driver does IG off-operation. The engine ECU as an engine control means gradually reduces target rotation speed (step S60) while prohibiting fuel injection cut to the engine from a point of time when the vehicle driver does IG off-operation. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an internal combustion engine control device that controls driving of an internal combustion engine, and an internal combustion engine control system including the device.

  A conventional valve timing adjustment mechanism that adjusts the opening / closing timing of at least one of an intake valve and an exhaust valve includes a drive-side rotating body that rotates with a crankshaft (drive shaft) of an internal combustion engine, and a driven that rotates with a camshaft (driven shaft). The hydraulic oil is supplied from the hydraulic pump so as to rotate the driven-side rotator relative to the drive-side rotator. Then, the direction of relative rotation of the driven-side rotator is controlled by switching the supply destination of the hydraulic oil with a control valve.

  Here, due to receiving a force from the valve spring, the cam shaft receives torque in a direction that prevents rotation during valve opening operation, and receives torque in a direction that promotes rotation during valve closing operation. In other words, the camshaft receives periodically varying torque (hereinafter referred to as fluctuating torque), and this fluctuating torque is transmitted to the driven side rotating body via the camshaft. At the start of the internal combustion engine, the hydraulic pressure of the hydraulic oil supplied to one of the rotating bodies is still low, so that the driven rotating body swings with respect to the driving rotating body due to the varying torque. Then, there arises a problem that a hitting sound is generated by colliding with the driving side rotating body, and a problem that a time required for relatively rotating one rotating body to the target position is increased.

  Conventionally, as a countermeasure against these problems, a lock mechanism that locks one of the rotating bodies at the most retarded angle position or the most advanced angle position so as not to be relatively rotatable is provided. Then, when an off operation (hereinafter referred to as an IG off operation) of an ignition switch for commanding the stop of the internal combustion engine is detected, the control valve is set so that one of the rotating bodies is relatively rotated toward the lock position. The lock control to be controlled is executed. According to this, when the ignition switch is turned on next time to start the internal combustion engine, the driven-side rotator is locked by the lock mechanism, so that the drive-side rotator is swayed even if it receives a varying torque. It wo n’t happen. Therefore, it is possible to reduce the generation of the hitting sound and the relative rotation time.

  However, since the hydraulic pump uses an internal combustion engine as a drive source, the hydraulic pressure decreases after the IG OFF operation. Then, depending on the temperature of the hydraulic oil and other various conditions, even if the lock control is performed, one of the rotating bodies may not reach the lock position.

Therefore, in the internal combustion engine control apparatus described in Patent Document 1, the decrease in hydraulic pressure after the IG off operation is delayed by delaying the timing of cutting the fuel injection to the internal combustion engine after the IG off operation.
JP 2002-357136 A

  However, in delaying the fuel injection cut after the IG off operation, the ignition switch operator does not immediately decrease the crankshaft rotation speed despite the IG off operation, so the delay time is long. If it is too much, the operator will feel uncomfortable.

  As a countermeasure against this, in the internal combustion engine control device described in Patent Document 1, the fuel injection cut is forcibly executed when a predetermined time (time exemplified by reference symbol T1 in FIG. 8) elapses from the IG OFF operation time point. For this reason, even if the lock control is performed after the IG-off operation, there is still a case where one of the rotating bodies cannot reach the locked position. The problem of long time has not been solved sufficiently.

  The present invention has been made to solve the above-described problems, and has as its object to alleviate the uncomfortable feeling given to an operator who has performed an off operation for instructing the stop of the internal combustion engine, and a rotating body after the off operation. It is an object to provide an internal combustion engine control device that is compatible with improving the certainty of locking the engine.

  Hereinafter, means for solving the above-described problems and the operation and effects thereof will be described.

  The invention according to claim 1 is applied to an internal combustion engine equipped with a valve timing adjustment mechanism for adjusting an opening / closing timing of at least one of an intake valve and an exhaust valve, and the rotational speed of the drive shaft of the internal combustion engine is set to a target rotational speed. An internal combustion engine control apparatus comprising engine control means for controlling the drive of the internal combustion engine so as to approach the valve, wherein the valve timing adjusting mechanism transmits a driving force from the drive shaft to a driven shaft that opens and closes the valve. A driving-side rotating body that rotates with the driving shaft, a driven-side rotating body that rotates with the driven shaft, and the internal combustion engine as a driving source, and one of the rotating bodies is the other. A hydraulic pump that supplies hydraulic oil so as to rotate relative thereto, and controls the relative rotational position of the one rotating body by controlling the supply state of the hydraulic oil. An advance / retard angle position control means, and a lock mechanism that locks the one rotating body at the most retarded angle position or the most advanced angle position so as not to rotate relative to each other. When an off operation for instructing to stop the internal combustion engine is detected, lock control is performed to relatively rotate the one rotating body toward the lock position, and the engine control means detects the off operation. In this case, the target rotational speed is gradually decreased while prohibiting fuel injection cut to the internal combustion engine.

According to this, when the off operation is detected, the target rotational speed is gradually decreased while prohibiting the fuel injection cut. Therefore, when the off operation is performed, the rotational speed of the drive shaft starts to decrease. Therefore, even if the period during which the fuel injection cut is prohibited to increase the certainty of locking the rotating body is longer than the predetermined time (T1) in Patent Document 1, the uncomfortable feeling given to the off-operated operator can be reduced.
Therefore, it is possible to reduce both the uncomfortable feeling given to the operator who has turned off the ignition switch and to increase the certainty of locking the rotating body after the turning-off operation.

  In addition, the above “gradual decrease” means a step-like decrease as exemplified by a one-dot chain line, in addition to the case of decreasing linearly with the passage of time as exemplified by the solid line in FIG. This also includes the case where

  According to a second aspect of the present invention, when the engine control unit detects the off operation, the engine control unit sets the target rotation speed toward a predetermined rotation speed that can secure a hydraulic pressure necessary to relatively rotate the one rotating body. It is characterized by being gradually lowered. According to this, when the engine control means performs the drive control of the internal combustion engine in consideration of the balance between reducing the sense of incongruity given to the operator and increasing the locking reliability of the rotating body, the rate of decrease when the engine control means gradually decreases is controlled. Therefore, the engine control means can easily perform drive control of the internal combustion engine in consideration of the balance.

  According to a third aspect of the present invention, the engine control means is configured to reduce the time required for the rotation to decrease until the actual rotational speed of the drive shaft decreases and reaches the predetermined rotational speed based on the amount of change in the actual rotational speed of the drive shaft. First estimation means for estimating the first rotation means, and second estimation means for estimating the time required for the lock to reach the lock position based on the actual relative rotation position of the one rotation body. In addition, a reduction rate when the target rotational speed is gradually reduced is determined according to the estimated both required times. According to this, it is possible to control with high accuracy in performing control so that the actual rotation reduction required time is a time in consideration of the aforementioned balance.

  According to a fourth aspect of the present invention, when the estimated time required for the lock is longer than the time required for rotation reduction, the engine control means is configured to gradually decrease the target rotational speed as the difference between the two required times increases. It is characterized in that the rate of decrease of is reduced. Therefore, the certainty of locking the rotating body after the off operation can be further enhanced.

  According to a fifth aspect of the present invention, the engine control means is configured so that the one rotary body reaches the lock position before the actual rotational speed of the drive shaft decreases and reaches the predetermined rotational speed. The reduction rate when gradually reducing the target rotational speed is determined. Therefore, the rotating body can be reliably locked after the off operation.

  According to a sixth aspect of the present invention, the engine control means determines whether the one rotating body has reached the lock position when the actual rotational speed of the drive shaft decreases and reaches the predetermined rotational speed. Nevertheless, the fuel injection cut to the internal combustion engine is executed. Therefore, the uncomfortable feeling given to the operator who has turned off the ignition switch can be further reduced.

  According to a seventh aspect of the present invention, when the one rotational body reaches the position of the lock, the engine control means, when the actual rotational speed of the drive shaft does not reach the predetermined rotational speed, A fuel injection cut to the internal combustion engine is executed. According to this, as compared with the case where the fuel injection cut is prohibited despite reaching the lock position, it is possible to avoid useless fuel injection and to reduce the uncomfortable feeling given to the operator who has performed the off operation.

  According to an eighth aspect of the present invention, the engine control means is configured so that the actual relative rotational position of the one rotating body, the actual rotational speed of the drive shaft, the temperature of the hydraulic oil, and the drive shaft at the time of the off operation. The reduction rate when the target rotational speed is gradually reduced is determined using at least one of the shift positions of the transmission for switching the reduction ratio as a parameter.

  These parameters affect at least one of the time required for rotation reduction until the actual rotational speed of the drive shaft decreases and reaches a predetermined rotational speed, and the time required for locking until the rotating body reaches the lock position. Therefore, since the reduction rate is determined as a parameter that affects the required time, the engine control means can easily perform drive control of the internal combustion engine in consideration of the balance.

  Incidentally, the required lock time becomes longer as the actual relative rotational position at the time of the off operation is farther from the lock position. In addition, the faster the actual rotation speed of the drive shaft at the time of the off operation, the longer the time required for rotation reduction. Further, the lower the temperature of the hydraulic oil, the higher the viscosity of the hydraulic oil and the lower the hydraulic pressure, so that the required lock time becomes longer. Further, since the mechanical friction loss in the transmission or the like varies depending on the shift position, the time required for rotation reduction varies. For example, when the shift position is in the travel range (D range), the mechanical friction loss is larger than that in the neutral range (N range), so the time required for rotation reduction is shortened.

  A ninth aspect of the invention includes the internal combustion engine control device according to any one of the first to eighth aspects, and a valve timing adjusting mechanism that adjusts an opening / closing timing of at least one of the intake valve and the exhaust valve. An internal combustion engine control system. According to this internal combustion engine control system, the various effects described above can be exhibited in the same manner.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of the invention will be described with reference to the drawings.

  As shown in FIG. 1, a gasoline engine 11 is applied to an internal combustion engine mounted on a vehicle and serving as a travel drive source, and the engine 11 is a double overhead cam type. The power from the crankshaft 12 (drive shaft) is transmitted to the intake side camshaft 16 (driven shaft) and the exhaust side camshaft 17 via the sprockets 14 and 15 by the timing chain 13. . However, the intake side camshaft 16 is provided with a valve timing adjusting device 18 that adjusts the advance amount of the intake side camshaft 16 with respect to the crankshaft 12. A cam angle sensor 19 for detecting the cam angle is installed on the outer peripheral side of the intake side cam shaft 16, while a crank angle sensor 20 for detecting the crank angle is installed on the outer peripheral side of the crank shaft 12. Yes.

  Output signals from the crank angle sensor 20 and the cam angle sensor 19 are input to an engine ECU 21 as engine control means. Then, the actual valve timing of an intake valve (not shown) is calculated by the engine ECU 21 and the engine rotation speed is calculated from the frequency of the output pulse of the crank angle sensor 20. Further, output signals from various sensors (intake pressure sensor 22, water temperature sensor 23, throttle sensor 24, etc.) for detecting the engine operating state and output signals from the ignition switch 25 are input to the engine ECU 21. Note that when the ignition switch 25 is turned off by the vehicle driver, a stop command signal for stopping the engine 11 is input to the engine ECU 21.

  The engine ECU 21 performs fuel injection control and ignition control based on these various input signals, and also performs variable valve timing control, which will be described later, and actual valve timing of the intake valve (actual advance angle amount of the intake camshaft 16). The valve timing of the valve timing adjusting device 18 is feedback-controlled so as to match the target valve timing (target advance amount).

  Oil in the oil pan 27 is supplied to the hydraulic circuit of the valve timing adjusting device 18 as hydraulic oil by a hydraulic pump 28. The hydraulic pump 28 uses the engine 11 as a drive source, and power from the crankshaft 12 is transmitted by a timing chain.

  Then, by switching the hydraulic oil supply destination by the hydraulic pump 28 with the hydraulic control valve 29, it is controlled whether the valve timing is changed to the advance side or the retard side. Further, by controlling the amount of hydraulic oil supplied by the hydraulic control valve 29, the actual advance angle amount (actual valve timing) of the intake camshaft 16 is controlled.

  The positive terminal side of the battery 73 is connected to the power supply terminal of the engine ECU 21 via the switch 72 of the main relay 71. When an on signal is input from the ignition switch 25, the engine ECU 21 energizes the relay drive coil 74 of the main relay 71 to turn on the switch 72 of the main relay 71 and receives supply of power from the battery 73. The power supplied through the main relay 71 is supplied to the entire control system such as the hydraulic control valve 29 in addition to the engine ECU 21. The main relay 71 is continuously kept on for a predetermined time after the ignition switch 25 is turned off, and the lock control described later can be executed during that period.

  Next, the configuration of the valve timing adjusting device 18 will be described with reference to FIGS.

  A housing 31 (drive side rotator (the other rotator)) of the valve timing adjusting device 18 is fastened and fixed by bolts 32 to a sprocket 14 that is rotatably supported on the outer periphery of the intake side camshaft 16. Thereby, the rotation of the crankshaft 12 is transmitted to the sprocket 14 and the housing 31 through the timing chain 13, and the sprocket 14 and the housing 31 rotate in synchronization with the crankshaft 12.

  On the other hand, the intake side camshaft 16 is rotatably supported by a cylinder head 33 and a bearing cap 34, and a rotor 35 (driven side rotary body (one rotary body)) is a stopper at one end of the intake side camshaft 16. It is fastened and fixed with bolts 37 through 36. The rotor 35 is accommodated in the housing 31 so as to be relatively rotatable.

  As shown in FIGS. 3 and 4, a plurality of hydraulic chambers 40 are formed inside the housing 31, and each hydraulic chamber 40 is delayed from the advance chamber 42 by a vane 41 formed on the outer peripheral portion of the rotor 35. It is partitioned into a corner chamber 43. Seal members 44 are attached to the outer periphery of the rotor 35 and the outer periphery of the vane 41, and each seal member 44 is urged in the outer peripheral direction by a leaf spring 45 (see FIG. 2). Thus, the gap between the outer peripheral surface of the rotor 35 and the inner peripheral surface of the housing 31 and the gap between the outer peripheral surface of the vane 41 and the inner peripheral surface of the hydraulic chamber 40 are sealed by the seal member 44.

  As shown in FIG. 2, an annular advance groove 46 and a retard groove 47 formed in the outer peripheral portion of the intake side camshaft 16 are connected to predetermined ports of the hydraulic control valve 29, respectively. By driving the pump 28, oil (operating oil) pumped from the oil pan 27 is supplied to the advance groove 46 and the retard groove 47 via the hydraulic control valve 29. The advance oil passage 48 connected to the advance groove 46 is formed so as to penetrate the inside of the intake side camshaft 16 and communicate with an arcuate advance oil passage 49 (see FIG. 3) formed in the rotor 35. The arcuate advance oil passage 49 communicates with each advance chamber 42. On the other hand, the retard oil passage 50 connected to the retard groove 47 passes through the inside of the intake camshaft 16 and communicates with an arc retard oil passage 51 (see FIG. 4) formed in the rotor 35. The arc-shaped retarded oil passage 51 communicates with each retarded angle chamber 43.

  The hydraulic control valve 29 is a four-port three-position switching valve that drives the valve element with a solenoid 53 and a spring 54. The position of the valve element is an advance angle supply position for supplying hydraulic oil to the advance angle chamber 42, and a retard angle. It is switched between a retard supply position for supplying hydraulic oil to the chamber 43 and a holding position for not supplying hydraulic oil to any of the advance chamber 42 and the retard chamber 43. When the energization of the solenoid 53 is stopped, the valve element is automatically switched to the position where the hydraulic oil is supplied to the advance chamber 42 by the spring 54, so that the hydraulic pressure acts in the direction in which the camshaft phase is advanced. The hydraulic control valve 29 shown in FIGS. 1 and 2 shows an operating state when the solenoid 53 is energized.

  In a state where the hydraulic pressure higher than a predetermined pressure is supplied to the advance chamber 42 and the retard chamber 43, the vane 41 is fixed by the hydraulic pressure of the advance chamber 42 and the retard chamber 43, and the housing 31 is rotated by the rotation of the crankshaft 12. The rotation is transmitted to the vane 41 via the hydraulic oil. Thereby, the crankshaft 12 and the intake side camshaft 16 rotate integrally in a state where the fluctuation of the rotor 35 described above is suppressed from swinging with respect to the housing 31.

  During engine operation, the hydraulic pressure in the advance chamber 42 and the retard chamber 43 is controlled by the hydraulic control valve 29 to rotate the rotor 35 relative to the housing 31, thereby rotating the intake side camshaft 16 relative to the crankshaft 12. The valve timing of the intake valve is varied by controlling the phase (cam shaft phase). Specifically, the hydraulic control valve 29 is operated to the above-described advance angle supply position or retard angle supply position to rotate the rotor 35 relatively, and when the target relative rotation position is reached, the hydraulic control valve 29 is operated to the holding position. Thus, the relative rotational position of the rotor 35 is held.

  Here, when the intake side camshaft 16 drives the intake valve, the intake side camshaft 16 receives fluctuating torque that fluctuates positively and negatively from a valve spring that urges the intake valve in the valve closing direction. The fluctuation torque in the positive direction represents torque in a direction in which the rotor 35 is relatively rotated toward the retard side, and the fluctuation torque in the negative direction represents torque in a direction in which the rotor 35 is relatively rotated toward the advance side. The average of the fluctuation torque works in the positive direction, that is, in the retard direction. Therefore, when the rotor 35 is relatively rotated to the advance side, the hydraulic pressure to be relatively rotated in the advance direction in order to avoid deterioration of the response of the relative rotation as compared to the case of relative rotation to the retard side. Is provided with a coil spring 55 (see FIG. 2) as a spring member that assists with the spring force. The coil spring 55 is accommodated in the sprocket 14.

  As shown in FIGS. 3 and 4, a lock pin 58 (for locking the rotor 35 relative to the housing 31 so as not to rotate relative to the housing 31) is formed in the lock pin accommodation hole 57 formed in any one vane 41. The lock pin 58 is housed in a retractable manner, and the lock pin 58 is fitted into the lock hole 59 (lock mechanism) shown in FIG. Locked at the position (lock position).

  As shown in FIGS. 5 and 6, the lock pin 58 is slidably inserted into the cylindrical member 61 fitted to the inner periphery of the lock pin accommodation hole 57, and is locked in the locking direction (protruding direction) by the spring 62. It is energized. In addition, a gap between the cylindrical member 61 and the lock pin 58 is divided into a lock hydraulic chamber 64 and a release holding hydraulic chamber 65 for unlocking and holding by a valve portion 63 formed at the center outer peripheral portion of the lock pin 58. Yes. In order to supply hydraulic oil from the advance chamber 42 to the lock hydraulic chamber 64 and the release holding hydraulic chamber 65, the vane 41 has a lock oil passage 66 communicating with the advance chamber 42 and an oil passage for unlocking and holding. 67 is formed. The housing 31 is formed with an unlocking oil passage 68 that communicates the lock hole 59 and the retard chamber 43.

  As shown in FIG. 5, when the lock pin 58 is locked, the valve portion 63 of the lock pin 58 blocks the lock release holding oil passage 67, and the lock oil passage 66 communicates with the lock hydraulic chamber 64. . As a result, hydraulic pressure is supplied from the advance chamber 42 to the lock hydraulic chamber 64, and the lock pin 58 is held in the lock hole 59 by the hydraulic pressure and the spring 62, and the camshaft phase is at the most retarded position. Locked.

  While the engine is stopped, the hydraulic pressure in the lock hydraulic chamber 64 (the hydraulic pressure in the advance chamber 42) decreases, but the lock pin 58 is held in the locked position by the spring 62. Therefore, the engine is started in a state where the lock pin 58 is held at the locked position (most retarded position), and when the hydraulic pressure in the lock hole 59 (hydraulic pressure in the retarded chamber 43) becomes high after the engine is started, the hydraulic pressure is increased. Thus, the lock pin 58 is unlocked as follows. After the engine is started, the hydraulic pressure (force in the unlocking direction) supplied from the retard chamber 43 through the unlocking oil passage 68 to the lock hole 59 is the hydraulic pressure in the lock hydraulic chamber 64 (hydraulic pressure in the advance chamber 42) and the spring 62. When the resultant force becomes larger than the resultant force of the spring force (force in the locking direction), the lock pin 58 is pushed out of the lock hole 59 by the hydraulic pressure of the lock hole 59 and moves to the unlock position shown in FIG. Is done.

  In this unlocked state, as shown in FIG. 6, the valve portion 63 of the lock pin 58 closes the lock oil passage 66, and the lock release holding oil passage 67 communicates with the release holding hydraulic chamber 65. . As a result, the hydraulic pressure is supplied from the advance chamber 42 to the release holding hydraulic chamber 65, and the hydraulic pressure in the release holding hydraulic chamber 65 (hydraulic pressure in the advance chamber 42) and the hydraulic pressure in the lock hole 59 (hydraulic pressure in the retard chamber 43) As a result, the lock pin 58 is held in the unlocked position against the spring 62. During engine operation, the hydraulic pressure of either the advance chamber 42 or the retard chamber 43 is high, so that the lock pin 58 is held at the unlocked position by the hydraulic pressure, and the rotor 35 is relatively rotatable. (In other words, the valve timing control is possible).

  The engine ECU 21 also functions as an advance / retard angle position control means for controlling the operation of the hydraulic control valve 29 by controlling the operation of the solenoid 53, and the intake valve based on the output signals of the crank angle sensor 20 and the cam angle sensor 19. The actual valve timing (actual advance angle amount of the intake camshaft 16) is calculated, and the target valve timing of the intake valve is based on the outputs of various sensors that detect the engine operating state such as the intake pressure sensor 22 and the water temperature sensor 23. (Target advance amount of intake camshaft 16) is calculated. Then, the hydraulic control valve 29 of the valve timing adjusting device 18 is feedback-controlled so that the actual valve timing of the intake valve coincides with the target valve timing.

  In other words, the engine ECU 21 controls the hydraulic pressure in the advance chamber 42 and the retard chamber 43 to set the actual relative rotation position (corresponding to the actual advance amount) of the rotor 35 with respect to the housing 31 to the target relative rotation position (target advance position). The camshaft phase is changed so that the actual valve timing of the intake valve matches the target valve timing.

  Thereafter, when the engine 11 is stopped, when the engine rotation speed is decreased, the discharge pressure of the hydraulic pump 28 is decreased, so that the hydraulic pressure in the advance chamber 42 and the retard chamber 43 is decreased. As a result, the hydraulic pressure of the release holding hydraulic chamber 65 (hydraulic pressure of the advance chamber 42) and the hydraulic pressure of the lock hole 59 (hydraulic pressure of the retard chamber 43) are reduced, so that the spring force of the spring 62 overcomes these hydraulic pressures. Then, the lock pin 58 protrudes and fits into the lock hole 59 by the spring force of the spring 62. However, in order for the lock pin 58 to be fitted into the lock hole 59, it is a condition that the positions of the two coincide with each other, that is, the rotor 35 coincides with the most retarded position.

  Next, the lock control program shown in FIG. 7 executed by the microcomputer of the engine ECU 21 as the engine control means and the advance / retard position control means will be described.

  This lock control program is periodically executed during the operation of the engine ECU 21. When this program is started, first, in step S10, it is determined whether or not the ignition switch 25 is turned off by the vehicle driver and the ignition switch 25 is switched from the on state to the off state. As described above, since the main relay 71 is kept on for a predetermined time after the ignition switch 25 is turned off, the lock control described below can be executed during that period.

  If it is determined that the ignition switch 25 has been switched from the on state to the off state (S10: YES), the following detected values at the time when the ignition switch 25 is switched to the off state (off operation point) are read. That is, the actual advance angle (CA), the actual engine speed (rpm), the operating oil temperature (° C.), and the shift position of the transmission are read. Then, a subtraction amount ΔNE (a decrease amount) of the target engine speed is calculated using these detected values as parameters.

  Specifically, the subtraction amount ΔNE is decreased as the actual relative rotational position at the time of the off operation is located on the advance side away from the lock position (most retarded position). Further, the subtraction amount ΔNE is increased as the actual engine speed at the time of the off operation is higher. Further, the lower the hydraulic oil temperature at the time of the off operation, the smaller the subtraction amount ΔNE. Further, when the shift position is a preset high friction loss range (for example, D range), the subtraction amount ΔNE is made smaller than when the shift position is a preset low friction loss range (for example, N range).

  Incidentally, before the IG is turned off, the target engine speed (rpm) is a target value used when the actual engine speed is controlled to the idle speed, and in step S20, the target engine speed at the time of the off operation. Read the speed.

  When it is determined that it is not the on-operation time (S10: NO), the process proceeds to step S30. If it is determined in step S30 that the ignition switch 25 is in the off state (IG off state) (S30: YES), the process proceeds to step S40 without executing the subtraction amount ΔNE calculation process in step S20. On the other hand, if it is determined that the IG is not off (S30: NO), the process is terminated.

  In step S40, it is determined whether or not the actual advance amount is greater than zero, that is, whether or not the rotor 35 is not at the most retarded position. If it is determined that the actual advance amount is greater than zero (not the most retarded angle position) (S40: YES), the process proceeds to step S50, and the hydraulic control valve 29 is operated so that the actual phase becomes the most retarded angle phase. Control. Specifically, in step S50, energization of the solenoid 53 is turned on to operate the hydraulic control valve 29 to the state shown in FIG. Thus, the lock control is performed in which the rotor 35 is relatively rotated toward the lock position (most retarded angle position) and the lock pin 58 is fitted into the lock hole 59.

  When it is determined that the actual advance amount is zero (at the most retarded angle position) (S40: NO), it is assumed that the lock pin 58 is already fitted in the lock hole 59, and the above-described The process proceeds to step S130 without performing lock control, and engine stop control described later is executed.

  In the subsequent step S60, the target engine rotation speed is reduced by subtracting the subtraction amount ΔNE calculated in step S20 from the target engine rotation speed at the time of IG off operation read in step s20. In the subsequent step S70, the throttle opening is controlled so that the actual engine speed approaches the target engine speed reduced in step S60. Incidentally, the amount of fuel injected from the injector is also controlled in conjunction with the throttle opening.

  Next, in step S80 as the second estimating means, the lock required time A until the rotor 35 reaches the lock position (most retarded angle position) is calculated based on the actual advance angle amount (actual relative rotation position) and the rate of change thereof. presume. Further, in step S90 as the first estimating means, based on the actual engine rotation speed and the rate of change thereof, the rotation reduction required time B until the actual engine rotation speed decreases and reaches a predetermined value (predetermined rotation speed) is estimated. .

  The predetermined value is set so as to be a minimum engine rotation speed at which the hydraulic pressure necessary to relatively rotate the rotor 35 can be secured, and is a value lower than the idle rotation speed when the engine 11 is idling. Is set to Incidentally, the idle rotation speed is variably set according to the engine coolant temperature detected by the water temperature sensor 23 and the operating state of the auxiliary equipment such as the compressor of the air conditioner.

  Then, in step S100, the rotation reduction required time B and the lock required time A are compared, and if it is determined that the lock required time A <the rotation decrease required time B is not satisfied (S100: NO), the process proceeds to step S110. In step S110, the subtraction amount ΔNE is corrected so as to reduce the subtraction amount ΔNE calculated in step S20.

  After the process of step S110, or when it is determined that the lock required time A <the rotation reduction required time B (S100: YES), the process proceeds to step S120. In step S120, it is determined whether or not the actual engine rotation speed is smaller than the predetermined value (idle rotation speed). If it is determined that the actual engine rotation speed is smaller than the predetermined value (S120: YES), the actual advance angle is determined. Regardless of whether or not the amount is zero (regardless of whether or not the most retarded position has been reached), in step S130, the fuel injection to the engine 11 is cut and the operation of the ignition device is stopped. Execute cut control. As a result, the actual engine speed is quickly reduced to zero.

  On the other hand, even if it is determined that the actual engine speed ≧ predetermined value (S120: NO), it is determined in step S140 that the actual advance amount is zero (has reached the most retarded position) (S140). : YES), the process proceeds to step S130, and the above-described fuel injection cut and ignition stop are executed. Further, when it is determined that the actual engine speed ≧ predetermined value (S120: NO), when the actual advance amount is not determined to be zero (the position has reached the most retarded angle position) (S140: NO), the processing is performed. Exit.

  Next, changes with time in the actual engine speed, the actual advance amount, and the like according to the above-described lock control program will be described with reference to the timing chart of FIG.

  In addition, the dotted line in FIG. 8 shows the various changes by the conventional control described in Patent Document 1, and the solid line in FIG. 8 shows the various changes by the lock control according to the present embodiment. 8A shows the on / off state of the ignition switch 25, FIG. 8B shows the shift position of the transmission, FIG. 8C shows the hydraulic oil temperature, and FIG. 8D shows the actual engine. The rotation speed is indicated, the (e) column indicates the target engine rotation speed, the (f) column indicates the throttle opening, and the (g) column indicates the actual advance amount.

  First, when the ignition switch 25 is turned on at the time indicated by t1 in FIG. 8 and the engine 11 is started, the hydraulic oil temperature rises, the actual engine speed increases, and the throttle is opened in accordance with the accelerator operation of the vehicle driver. The degree changes. Since the lock pin 58 is fitted in the lock hole 59 when the engine is started, the rotor 35 is in the lock position (most retarded position), and the actual advance amount is zero.

  Here, it is desirable to reduce the overlap period between the valve opening period of the intake valve and the valve opening period of the exhaust valve during low speed operation such as when starting the engine, and it is desirable to increase the overlap period during high speed operation. . This is because, during high-speed operation, even if the overlap period is increased, the intake air flows into the combustion chamber so that it is pulled by the exhaust gas, so that the intake air amount can be increased and thus the engine output can be improved. On the other hand, if the overlap period is increased during low-speed operation, the burned gas cannot be discharged from the combustion chamber and stays there, and combustion becomes unstable.

  For these reasons, the rotor 35 is controlled to the most retarded position when the engine is started. However, in order to improve the engine output as the actual engine speed increases, the rotor 35 is advanced by increasing the actual advance amount. It is rotating relative to the side.

  Next, when the ignition switch 25 is turned off at time t2 in FIG. 8, as shown in the column (e) of FIG. 8, the target engine speed is gradually reduced by the control in step S60. As a result, the throttle opening is controlled to be gradually reduced, and the actual engine speed is gradually reduced. Further, at time t2 when the IG-off operation is performed, the lock control in step S50 is executed, the rotor 35 relatively rotates toward the most retarded angle position, the actual advance amount decreases, and the lock position is reached at time t3. Reach (most retarded position).

  At time t3, the fuel injection cut control according to step S130 is executed, and the target engine speed becomes zero. As a result, the throttle opening becomes zero, the actual engine speed decreases faster than the period from t2 to t3, and the actual engine speed becomes zero at time t4. Incidentally, the solid line in the column of FIG. 8B indicates the N range or the P range, and the alternate long and short dash line indicates the D range.

  Next, as a comparison with the present embodiment, a timing chart based on conventional control indicated by a dotted line in FIG. 8 will be described.

  According to the conventional control, the lock control is executed while maintaining the target engine rotational speed until a predetermined time T1 elapses from the time point t2 of the IG off operation. Then, at a time t30 when the predetermined time T1 has elapsed from the time t2, the fuel injection cut control is executed with the target engine speed set to zero in order to avoid a sense of incongruity for the driver who has performed the IG off operation. Therefore, as shown by the dotted line in FIG. 8 (g), when the actual engine speed reaches a predetermined value, the rotor 35 cannot be rotated relatively, and the actual advance amount does not become zero (the lock position is reached). Without) the actual rotation speed becomes zero, and the engine 11 stops.

  As described above, in the conventional control, the lock control is executed while maintaining the target engine speed from the time point t2 of the IG off operation to the time point t30 when the predetermined time T1 elapses. The actual engine speed at T1) remains at the IG-off operation time point t2. Therefore, the discomfort given to the driver who performed the IG off operation is large. On the other hand, according to the control of the present embodiment, since the target engine speed is gradually decreased from the time point t2 of the IG off operation, the actual engine speed is gradually decreased from the time point t2 of the IG off operation. Therefore, the uncomfortable feeling given to the driver can be reduced.

  In other words, since the target engine speed is gradually decreased from the time point t2 when the IG off operation is performed, the actual engine speed starts to decrease as soon as the IG off operation is performed. Therefore, even if the period during which fuel injection cut is prohibited (the period from t2 to t3) is longer than the predetermined time T1 in the conventional control in order to increase the certainty that the rotor 35 is relatively rotated to reach the lock position, the IG OFF operation is performed. Can reduce the sense of discomfort given to the driver. Therefore, it is possible to achieve both of reducing the uncomfortable feeling given to the driver and enhancing the certainty that the rotor 35 reaches the lock position after the IG-off operation.

  Further, according to the present embodiment, the required rotation time B and the required lock time A are estimated (S80, S90), and if the required lock time A <the required rotation time B is not satisfied (S100: NO), the target engine The subtraction amount ΔNE for subtracting the rotation speed is reduced (S110). Therefore, the certainty of locking the rotor 35 after the IG off operation can be enhanced. Further, in step S110, if the subtraction amount ΔNE is decreased as the difference between the two required times A and B is larger, the certainty of locking the rotor 35 after the IG-off operation can be further increased.

  Further, according to the present embodiment, when it is determined that the actual engine speed <the predetermined value (S120: YES), the fuel injection cut control is executed regardless of whether the actual advance amount is zero or not. . Therefore, it is possible to reduce a sense of incongruity given to the driver who has performed the IG-off operation, as compared with a case where control is performed such that the actual engine rotation speed is maintained at the idle rotation speed to lock the rotor 35.

  Further, according to the present embodiment, the target engine rotational speed subtraction amount ΔNE is calculated using the actual advance angle amount, the actual engine rotational speed, the hydraulic oil temperature, and the transmission shift position at the IG-off operation time point t2 as parameters. (S20). These parameters affect the rotation reduction required time B and the lock required time A. Therefore, since the subtraction amount ΔNE is calculated as a parameter that affects these required times A and B, the subtraction amount ΔNE is set in consideration of the balance between reducing the uncomfortable feeling given to the driver and increasing the locking reliability of the rotor 35. The engine ECU 21 can easily do this.

  Further, according to the present embodiment, even when it is determined that the actual engine speed ≧ predetermined value (S120: NO), the actual advance amount is zero (has reached the most retarded position) in step S140. Is determined (S140: YES), fuel injection cut control is executed in step S130. According to this, as compared with the case where the fuel injection cut is prohibited despite reaching the lock position, it is possible to avoid useless fuel injection and reduce the uncomfortable feeling given to the driver who has performed the IG-off operation.

(Other embodiments)
The present invention is not limited to the description of the above embodiment, and may be modified as follows. Note that the characteristic structures of the embodiments may be arbitrarily combined.

  In the above embodiment, when calculating the subtraction amount ΔNE in step S20, the calculation is performed irrespective of the lock required time A and the rotation reduction required time B, but the lock required time A <the rotation reduction required time B. In this way, the subtraction amount ΔNE may be determined. According to this, the rotor 35 can be reliably locked after the IG off operation.

  In the above embodiment, the valve timing adjusting device 18 provided in the driving force transmission system of the intake side camshaft 16 is controlled, but the valve timing adjusting device provided in the driving force transmission system of the exhaust side camshaft 17 18 may be a control target. In this case, in order to reduce the overlap period between the intake valve opening period and the exhaust valve opening period during low speed operation such as when starting the engine, the lock position is locked so as to be the most advanced angle position. A lock mechanism such as the pin 58 is configured.

  In the above embodiment, the gasoline engine 11 is a control target, but a diesel engine may be the control target.

  In the above embodiment, the rotor 35 (one rotating body) that rotates in synchronization with the intake camshaft 16 (driven shaft) is rotated by the housing 31 (the other rotation) that rotates in synchronization with the crankshaft 12 (drive shaft). However, the housing 31 may be configured as one rotating body, and the housing 31 may be rotated relative to the rotor 35 serving as one rotating body.

  In the above embodiment, the target engine speed is linearly decreased with time from the time point t2 of the IG off operation, but the actual engine speed is a predetermined value as shown by the dashed line in FIG. It may be reduced in steps within a range not lower than (predetermined rotational speed).

1 is a schematic configuration diagram illustrating an entire control system according to an embodiment of the present invention. The longitudinal cross-sectional view which shows the valve timing adjustment apparatus of FIG. II sectional drawing of FIG. II-II sectional drawing of FIG. Sectional drawing which shows the locked state by the locking mechanism of FIG. Sectional drawing which shows the lock release state by the locking mechanism of FIG. The flowchart which shows the control content by engine ECU of FIG. FIG. 8 is a timing chart showing temporal changes in the actual engine rotation speed, the actual advance angle amount, and the like under the control of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Gasoline engine (internal combustion engine), 12 ... Crankshaft (drive shaft), 18 ... Valve timing adjusting device (valve timing adjusting mechanism), 21 ... Engine ECU (engine control means, advance / retard angle position control means), 28 ... Hydraulic pump (valve timing adjustment mechanism), 29 ... hydraulic control valve, 31 ... housing, 35 ... rotor, 58 ... lock pin (lock mechanism), 59 ... lock hole (lock mechanism).

Claims (9)

Applied to an internal combustion engine equipped with a valve timing adjustment mechanism for adjusting the opening / closing timing of at least one of an intake valve and an exhaust valve, and driving the internal combustion engine so that the rotational speed of the drive shaft of the internal combustion engine approaches a target rotational speed An internal combustion engine control device comprising engine control means for controlling
The valve timing adjusting mechanism is provided in a driving force transmission system that transmits a driving force from the driving shaft to a driven shaft that drives the valve to open and close, and a driving side rotating body that rotates together with the driving shaft, the driven shaft A driven-side rotating body that rotates together with the internal combustion engine, a hydraulic pump that supplies hydraulic oil to rotate one of the rotating bodies relative to the other, and the supply state of the hydraulic oil is controlled. Advancing / retarding position control means for controlling the relative rotational position of the one rotating body, and a locking mechanism for locking the one rotating body at the most retarded angle position or the most advanced angle position so as not to be relatively rotatable. ,
The advance / retard angle position control means executes lock control to relatively rotate the one rotating body toward the lock position when detecting an off operation for commanding the stop of the internal combustion engine,
The internal combustion engine control device according to claim 1, wherein the engine control means gradually reduces the target rotational speed while prohibiting fuel injection cut to the internal combustion engine when the off operation is detected.   The engine control means, when detecting the off operation, gradually reduces the target rotation speed toward a predetermined rotation speed capable of securing a hydraulic pressure necessary to relatively rotate the one rotating body. The internal combustion engine control apparatus according to claim 1. The engine control means includes
First estimating means for estimating a time required for rotation reduction until the actual rotational speed of the drive shaft decreases and reaches the predetermined rotational speed based on a change amount of the actual rotational speed of the drive shaft;
Second estimation means for estimating a lock required time until the one rotary body reaches the lock position based on the actual relative rotational position of the one rotary body;
And having
The internal combustion engine control device according to claim 2, wherein a rate of decrease when the target rotational speed is gradually decreased is determined according to the estimated required time.   When the estimated required lock time is longer than the required rotation decrease time, the engine control means reduces the decrease rate when the target rotation speed is gradually decreased as the difference between the required time is larger. The internal combustion engine controller according to claim 3, wherein   The engine control means gradually increases the target rotation speed so that the one rotating body reaches the lock position before the actual rotation speed of the drive shaft decreases and reaches the predetermined rotation speed. The internal combustion engine control device according to claim 3 or 4, wherein a reduction rate at the time of reduction is determined.   When the actual rotational speed of the drive shaft decreases and reaches the predetermined rotational speed, the engine control means transfers the internal combustion engine to the internal combustion engine regardless of whether the one rotating body has reached the lock position or not. 6. The internal combustion engine control device according to claim 2, wherein the fuel injection cut is executed.   The engine control means cuts off fuel injection to the internal combustion engine when the actual rotational speed of the drive shaft does not reach the predetermined rotational speed when the one rotating body reaches the lock position. The internal combustion engine control device according to any one of claims 2 to 5, wherein   The engine control means is a transmission that switches an actual relative rotational position of the one rotating body, an actual rotational speed of the drive shaft, a temperature of the hydraulic oil, and a reduction ratio of the drive shaft at the time of the off operation. 8. The internal combustion engine control device according to claim 1, wherein a reduction rate when the target rotational speed is gradually reduced is determined using at least one of the shift positions as a parameter. An internal combustion engine control device according to any one of claims 1 to 8,
A valve timing adjustment mechanism for adjusting the opening / closing timing of at least one of the intake valve and the exhaust valve;
An internal combustion engine control system comprising:

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