JP2009281151A - Electronic control apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic control apparatus capable of specifying a dead band region of each operating condition based on a learned dead band region of a driving hydraulic valve when the dead band region is learned once under any operating condition, even when there is a fluctuation of the operating condition such as a temperature of the dead band region. <P>SOLUTION: The electronic control apparatus 8 is for controlling the driving hydraulic valve 73 of a variable valve mechanism 6 that varies the operation of valves 23, 24 of an internal combustion engine. The electronic control apparatus 8 is equipped with: a storage part for storing a learning value of the dead band region in which responsiveness of the driving hydraulic valve 73 to a control value is remarkably late compared with another region or is hardly responsive, and the operating condition upon learning; and a control part for correcting the stored dead band region based a compared result of the operating condition upon controlling the driving hydraulic valve 73 and the stored operating condition, and controlling the driving hydraulic valve 73 based on the corrected dead band region. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electronic control device that controls a drive hydraulic valve of a variable valve mechanism that varies the operation of an intake valve and / or an exhaust valve of an internal combustion engine.

  In an engine as an internal combustion engine mounted on a recent vehicle or the like, for the purpose of improving fuel efficiency and engine output efficiency, the drive phase of valves such as an intake valve and an exhaust valve, that is, opening / closing timing (hereinafter referred to as a valve) A variable valve mechanism is provided which makes the timing variable).

  The variable valve mechanism advances (advances) or delays (retards) the valve timing based on the drive hydraulic pressure adjusted by the drive hydraulic valve, that is, displaces the valve timing.

  The adjustment of the drive hydraulic pressure with respect to the drive hydraulic valve will be described in detail. The control unit that controls the drive hydraulic valve calculates a control value based on the difference between the target valve timing and the current valve timing. The control unit calculates a control value that eliminates the difference between the target valve timing and the current valve timing, and controls the drive hydraulic valve with the calculated control value. In the drive hydraulic valve, the oil pressure supplied to the advance chamber and the retard chamber provided in the variable valve mechanism is changed by sliding a spool provided in the drive hydraulic valve based on the control value. Adjusted.

  As a result of the adjustment, the control unit calculates the difference based on the changed valve timing, and calculates the control value again based on the calculated difference. That is, the control unit executes feedback control that repeats the calculation of the control value so that the difference between the target valve timing and the current valve timing is eliminated.

  Due to the structure of the drive hydraulic valve, there is a dead zone where the hydraulic pressure supplied to the variable valve mechanism is extremely small when the spool position is within a predetermined range. Therefore, when a control value for positioning the spool in the predetermined range is input to the drive hydraulic valve, the hydraulic pressure supplied to the variable valve mechanism becomes small, and the displacement speed of the valve timing becomes extremely slow. There is a fear.

  In order to solve such a problem, the electronic control device that controls the variable valve mechanism learns the dead zone by operating the variable valve mechanism at the time of starting the vehicle, and thereafter, based on the dead zone calculated by learning. Thus, the process of changing the characteristic of the control value is executed.

  As a method for learning the dead zone region, for example, there are the following methods. In other words, the electronic control unit measures the displacement speed at the valve timing while changing the control value, and calculates the maximum value and the minimum value of the control values determined to be slower than the predetermined value set in advance. Then, a range from the minimum value to the maximum value is determined as a dead zone region.

  For example, Patent Document 1 discloses a variable valve device that varies at least one of valve timing, lift amount, working angle, and the like of an intake valve and / or an exhaust valve of an engine, and a drive hydraulic pressure that controls the drive hydraulic pressure of the variable valve device. A hydraulic control valve as a valve and a control means for outputting a control signal for controlling the hydraulic control valve, and whether the hydraulic control valve is slow in response to changes in the control signal in some control areas Or, it has a nonlinear control characteristic with a control region (dead zone) that hardly responds, and the control means increases the control gain when the control signal is in the dead zone, thereby increasing the response of the controlled object in the dead zone. A control device that can be improved is disclosed.

When the control device disclosed in Patent Document 1 inputs the duty value of the pulse signal as the control value to the linear solenoid of the hydraulic control valve, the duty value passes the upper limit value and the lower limit value of the dead zone. When using the fact that the responsiveness of the valve timing control changes suddenly, the responsiveness of the valve timing control is detected during engine operation, and the dead zone region is learned based on the duty value when the responsiveness changes suddenly. is doing.
JP 2007-107539 A

  By the way, the dead zone region varies depending on the operating condition of the vehicle. For example, as shown in FIG. 1A, the dead zone region becomes narrower as the oil temperature is higher, depending on the oil temperature supplied from the drive hydraulic valve to the variable valve device. Further, as shown in FIG. 1B, the relative position and width of the dead zone region with respect to the control duty value differ depending on the variation of each component used in the drive hydraulic valve or the like.

  For this reason, in a vehicle equipped with a variable valve mechanism, the electronic control unit learns the dead zone area by operating the variable valve mechanism when the engine is started, for example, and thereafter controls the variable valve mechanism based on the learned dead zone area. Until the next learning is executed (for example, at the next vehicle start-up), the dead zone region may change due to an increase in the oil temperature due to the warming up of the engine, which may cause a control error. .

  As an example of control error, in the control device disclosed in Patent Document 1, depending on how the dead zone changes, the process of increasing the control gain is not executed despite the dead zone. There is a risk that the slow displacement speed cannot be resolved. On the other hand, there is a possibility that the process of increasing the control gain is executed in spite of not being the dead zone region, and the valve timing is excessively advanced or retarded with respect to the target valve timing.

  In order to solve such a problem, for example, it is conceivable that the electronic control unit learns the dead zone region for each different temperature range obtained by dividing the temperature range that the oil temperature can take, but performs appropriate control. It is difficult.

  This is because it is difficult to set the oil temperature within a predetermined temperature range at the timing when the electronic control device performs learning of the dead zone region. Further, when the oil temperature falls within a predetermined temperature range, it is not always possible to learn the dead zone by the electronic control device.

  In view of the above-described conventional problems, the object of the present invention is to learn the dead zone area of the drive hydraulic valve once under any operating condition, and thereafter, the fluctuation due to the operating condition of the temperature, parts used, etc. in the dead zone area. Even if there is, the electronic control device is provided that can specify the dead zone for each operation condition based on the learned dead zone and appropriately control the drive hydraulic valve.

  In order to achieve the above object, the electronic controller according to the present invention is characterized in that it is an electronic controller for controlling a drive hydraulic valve of a variable valve mechanism that varies the operation of an intake valve and / or an exhaust valve of an internal combustion engine. A storage unit in which the learning value of the dead zone region in which the driving hydraulic valve is responsive to the control value is significantly slower than the other region or hardly responds and the operating condition at the time of learning are stored, and the driving hydraulic valve And learning value and operation condition at that time are stored in the storage unit, and the comparison result of the operation condition when controlling the drive hydraulic valve and the operation condition stored in the storage unit On the basis of this, there is a control unit that corrects the dead zone region stored in the storage unit and controls the drive hydraulic valve based on the corrected dead zone region.

  According to the above configuration, when the control unit learns the dead zone under a certain operating condition, even if the operating condition changes, the control unit corrects the dead zone based on the difference in operating conditions before and after the change, The drive hydraulic valve is controlled corresponding to the dead zone region.

  As described above, according to the present invention, once the dead zone area of the drive hydraulic valve is learned once under any operating condition, the dead zone area may subsequently vary due to operating conditions such as temperature and parts used. Thus, it is possible to provide an electronic control device that can appropriately control the drive hydraulic valve by specifying the dead zone for each operation condition based on the learned dead zone.

  Hereinafter, an embodiment in which an electronic control device according to the present invention is realized as an electronic control device for controlling an engine of a vehicle will be described.

  In this embodiment, an engine as an internal combustion engine of a vehicle is an engine having one cycle consisting of four strokes, and is composed of four cylinders of # 1, # 2, # 3, and # 4. The cylinders are configured to perform different driving by 1/4 cycle. In addition, the engine 1 of the vehicle shown in FIG. 2, which will be described below, is an extracted one of the four cylinders described above.

  As shown in FIG. 2, the vehicle engine 1 includes an internal combustion unit 2, and an intake unit 3 and an exhaust unit 4 that communicate with the internal combustion unit 2.

  The internal combustion unit 2 includes a piston 22 that reciprocates up and down with a pressure when an air-fuel mixture (a mixture of atomized fuel and air) burns in a combustion chamber 21a inside the cylinder 21, and a combustion chamber 21a. An intake valve 23 that opens and closes the intake port of the air-fuel mixture, an exhaust valve 24 that opens and closes the exhaust port to discharge combustion gas after the air-fuel mixture burns, and a crankshaft 25 that changes the reciprocating motion of the piston 22 into a rotational motion A connecting rod 26 that connects the piston 22 and the crankshaft 25, an ignition plug 27 for igniting the air-fuel mixture sucked into the combustion chamber 21a, and an optimal air-fuel ratio (a mixture ratio of air and fuel in the air-fuel mixture) A crank angle sensor 28 for detecting the angular position (crank angle) of the crankshaft 25 to specify the fuel injection timing, It is configured to include a water temperature sensor 29 for detecting a temperature of the cooling water.

  The crank angle sensor 28 includes a plurality of teeth 281 formed on the outer periphery of a crank rotor provided on the crankshaft 25 and an electromagnetic pickup 282 that reads the plurality of teeth.

  Here, the ignition plug 27 is ignited based on the ignition signal distributed by the distributor 51. The distributor 51 is provided to distribute the high voltage output from the igniter 52 to the spark plugs 27 of the respective cylinders in synchronization with the crank angle detected by the crank angle sensor 28.

  This will be described in detail below. The distributor 51 is connected to an exhaust camshaft 245 (to be described later) connected to an exhaust camshaft 245 which will be described later. Is provided. By detecting the rotational speed of the rotor by the rotational speed sensor, the rotational speed of the crankshaft 25, that is, the rotational speed of the engine is detected.

  Further, the distributor 51 is provided with a cylinder discrimination sensor 58 that detects a crank angle reference position of the crankshaft 25 at a predetermined ratio according to the rotation of the rotor and outputs the reference position signal.

  Then, the distributor 51 determines the spark plug 27 that distributes the high voltage output from the igniter 52 based on the detection values of the rotation speed sensor and the cylinder discrimination sensor 58.

  The intake section 3 is for sending fuel and air necessary for burning fuel to the internal combustion section 2. The intake section 3 serves to inject fuel into the intake pipe 31 serving as the air or fuel passage and the intake valve 23. An injector 32 as a fuel injection valve, an air filter 34 for purifying air sucked from the intake port 33, an air flow meter 35 for detecting the amount of sucked air, and a throttle valve 36 for controlling the amount of air sucked The throttle valve drive mechanism 37 that drives the throttle valve 36 based on the depression amount of the accelerator pedal detected by the accelerator opening sensor, and the throttle opening that detects the opening degree of the throttle valve 36 driven by the throttle valve drive mechanism 37. A degree sensor 38 and the like are provided.

  The exhaust unit 4 is for exhausting the gas burned in the internal combustion unit 2, and an exhaust passage 41 serving as a passage for the exhausted gas, a catalyst 42 for purifying the exhausted gas, and an oxygen concentration in the exhaust And an oxygen sensor 43 for detecting the above.

  Hereinafter, the opening and closing mechanisms of the intake and exhaust ports of the intake valve 23 and the exhaust valve 24 will be described in detail. The intake valve 23 and the exhaust valve 24 include stems 231 and 241 extending upward, and springs 232 and 242, valve lifters 233 and 243, and the like are provided above the stems 231 and 241. Cams 234 and 244 are provided to engage with the valve lifters 233 and 243, respectively.

  The intake camshaft 235 and the exhaust camshaft 245 are rotatably supported by a plurality of bearings on the cylinder head that covers the upper side of the cylinder 21. The cam 234 is integrally formed with the intake camshaft 235 as an axis, and the cam 244 is integrally formed with the exhaust camshaft 245 as an axis.

  The intake valve 23 and the exhaust valve 24 are urged upward, that is, in a direction to close the intake port and the exhaust port, by the urging forces of the springs 232 and 242.

  The power generated by the rotation of the crankshaft 25 during the operation of the engine 1 is transmitted to the timing gears 236 and 246 via the timing belt, and the camshafts 235 and 245 are driven to rotate, whereby the cams 234 and 244 rotate. Further, the valve lifters 233 and 243 are pressed against the urging force of the springs 232 and 242 in accordance with the curved shape of the side surfaces of the rotating cams 234 and 244, so that the intake valve 23 and the exhaust valve 24 move downward to take in the intake air. The mouth and the exhaust are each opened.

  The engine 1 is configured to include a variable valve mechanism 6 at the tip of the intake camshaft 235. The variable valve mechanism 6 can change the opening / closing timing of the intake valve 23 by changing the drive phase of the intake valve 23 relative to the rotation phase of the crankshaft 25, that is, the relative rotation phase of the intake camshaft 235, based on the hydraulic pressure. It is configured.

  As shown in FIGS. 3A and 3B, the variable valve mechanism 6 is fixed to a timing gear 236 connected to the crankshaft 25 via a timing belt 65, and is relative to the intake camshaft 235. A housing 61 that rotates, a vane rotor 62 that is installed inside the housing 61 and rotates together with the intake camshaft 235, a plurality of vanes 63 that are installed on the outer periphery of the vane rotor 62, and an oil pressure that is formed inside the housing 61 is introduced. And an oil chamber 64 to be configured. The housing 61 and the vane rotor 62 are configured to rotate together and rotate relative to each other.

  The oil chamber 64 is partitioned by the vane 63, the vane rotor 62, and the inner peripheral surface of the housing 61, and the retard chamber 64 a formed in the counter-rotating direction of the intake camshaft 235 with respect to the vane 63 and the vane 63. And an advance chamber 64b formed in the rotational direction of the intake camshaft 235.

  The retard chamber 64a and the advance chamber 64b are connected to an oil passage 64c to which oil is supplied by an oil circulation device 7 to be described later, and a retard chamber 64a and an advance angle by a hydraulic control valve 73 as a drive hydraulic valve to be described later. By adjusting the hydraulic pressure acting on the chamber 64b, the relative position of the vane 63 with respect to the oil chamber 64 is rotated, and the phase of the intake camshaft 235 is continuously varied.

  From the above description, the variable valve mechanism 6 is configured to be able to adjust the drive phase of the intake valve 23 relative to the rotational phase of the crankshaft 25 by being hydraulically driven via the hydraulic control valve 73. In other words, the variable valve mechanism 6 is configured to vary the operation of the intake valve 23 of the engine.

  In the present embodiment, as shown in FIG. 2, a timing gear 246 that is connected to the crankshaft 25 via a timing belt and rotates integrally with the exhaust camshaft 245 is provided at the tip of the exhaust camshaft 245. However, the variable valve mechanism 6 is not provided.

  As shown in FIG. 2, an oil circulation device 7 for supplying oil to the variable valve mechanism 6 includes an oil pan 71 for accumulating oil and an oil pump for supplying oil from the oil pan 71 to the variable valve mechanism 6 and the like. 72, a hydraulic control valve 73, and the like, and is configured to lubricate oil in each part of the engine 1 including the variable valve mechanism 6. The oil pressure of the oil supplied to the variable valve mechanism 6 is determined based on the opening degree of the oil pressure control valve 73. The relative rotational phase of the intake camshaft 235 with respect to the rotational phase of the crankshaft 25 changes depending on the magnitude of the hydraulic pressure.

  The oil pump 72 includes a rotating body such as a cam gear connected to the crankshaft 25, and various valves including various bearings, various pistons, and a hydraulic control valve 73 by driving the rotating body in conjunction with the driving of the engine 1. This is a mechanical oil pump that circulates oil stored in the oil pan 71 through devices such as the intake camshaft 235 and the exhaust camshaft 245. The oil pump 72 includes a rotating body such as a cam gear, and may be an electric oil pump that circulates oil by driving the rotating body by power feeding from a vehicle battery.

  Hereinafter, the hydraulic control valve 73 will be described in detail. As shown in FIG. 4A, the hydraulic control valve 73 includes a cylinder 731, a spool 732 that slides inside the cylinder 731, a linear solenoid 733 driven by a control signal from the electronic control device 8, and a linear solenoid And a spring 734 for urging the spool 732 in a direction opposite to that driven by the motor 733.

  An oil supply port 731a communicated with the oil pan 71 and the oil passage 64c through the oil pump 72, an oil discharge port 731b communicated with the oil pan 71 and the oil passage 64c, the retard chamber 64a and the oil passage through the cylinder 731. A hydraulic port 731c communicated by 64c and a hydraulic port 731d communicated by the advance chamber 64b and the oil passage 64c are formed.

  The opening degree of the hydraulic control valve 73 is determined by the current value supplied to the linear solenoid 733. That is, the electronic control unit 8 generates a control signal that is a pulse signal having a duty value that becomes the current value and outputs the control signal to the linear solenoid 733. The linear solenoid 733 sets the spool 732 to the cylinder based on the control signal. Slide in 731.

  4A to 4C show typical states of the hydraulic control valve 74, and FIG. 5 shows the characteristics of the displacement speed of the variable valve mechanism 6 with respect to the duty value of the control signal.

  FIG. 4A shows the state of the hydraulic control valve 73 when the duty value of the control signal is about 100%. In this case, the spool 732 is slid near the left end of the cylinder 731 by the linear solenoid 733. And as shown with a broken line in a figure, oil is supplied to the advance chamber 64b, and oil is discharged | emitted from the retard chamber 64a. As a result, in the variable valve mechanism 6, the relative position of the vane 63 with respect to the oil chamber 64 is displaced to a position that advances the opening / closing timing of the intake valve 23 (hereinafter referred to as valve timing).

  If the duty value is decreased from this state, the spool 732 is slid to the right, and the open areas of the hydraulic ports 731c and 731d are decreased. Therefore, as shown in the range A of FIG. 5, the displacement speed of the variable valve mechanism 6 decreases.

  FIG. 4B shows the state of the hydraulic control valve 73 when the duty value of the control signal is about 0%. In this case, the spool 732 is slid near the right end of the cylinder 731 by the linear solenoid 733. And as shown with the broken line in a figure, oil is supplied to the retardation chamber 64a, and oil is discharged | emitted from the advance chamber 64b. Thereby, in the variable valve mechanism 6, the relative position of the vane 63 with respect to the oil chamber 64 is displaced to a position that delays the valve timing.

  If the duty value is increased from this state, the spool 732 is slid to the left, and the open areas of the hydraulic ports 731c and 731d are reduced. Therefore, as shown in the range B of FIG. 5, the displacement speed of the variable valve mechanism 6 decreases.

  FIG. 4C shows the state of the hydraulic control valve 73 when the duty value of the control signal is about 50%. In this case, the spool 732 is slid by the linear solenoid 733 near the center of the cylinder 731, that is, at a position where the hydraulic ports 731 c and 731 d are closed. Thereby, in the variable valve mechanism 6, the relative position of the vane 63 with respect to the oil chamber 64 is maintained in the current state.

  However, in the hydraulic control valve 73, even if the spool 732 slides to a position where the hydraulic ports 731c and 731d are closed, the hydraulic ports 731c and 731d are not completely closed due to the mechanical structure. Is supplied to or discharged from the oil chamber 64. Therefore, in the range C of FIG. 5 in which the spool 732 is slid to a position where the hydraulic ports 731c and 731d are closed, the variable valve mechanism 6 is displaced to a position where the valve timing is increased or decreased in spite of a minute speed. . That is, this range C is a dead zone region of the hydraulic control valve 73.

  The engine 1 is provided with an electronic control unit 8 for operating the engine 1 by driving and controlling the blocks described above.

  As shown in FIG. 6, the electronic control unit 8 includes a microcomputer 81, an input interface circuit 82 for inputting analog signals and digital signals from various sensors, and an A / D converter 83 for converting the analog signals into digital signals. And an output interface circuit 84 for outputting signals obtained as a result of calculation by the microcomputer 81 based on the input signals to various actuators.

  The microcomputer 81 includes a CPU 811, a ROM 812 and / or EEPROM 814 in which a control program executed by the CPU 811 is stored, a RAM 813 used as a working area, and the like.

  The electronic control device 8 inputs detection values by the crank angle sensor 28, the water temperature sensor 29, the air flow meter 35, the throttle opening sensor 38, the oxygen sensor 43, etc., via the input interface circuit 82, and the CPU 811 From these detection values, digital control signals such as engine speed and throttle opening are calculated and calculated.

  Then, the electronic control unit 8 outputs the digital control signal calculated and calculated by the CPU 811 to the injector 32, the throttle valve drive mechanism 37, the igniter 52, the hydraulic control valve 73, and the like via the output interface circuit 84. Thus, the fuel injection amount and ignition timing of the engine 1 are controlled.

  In addition, the electronic control unit 8 controls the hydraulic control valve 73 based on the control value for adjusting the drive phase of the intake valve 23 to the target phase with respect to the variable valve mechanism 6 described above. A dead zone region where the flow rate of hydraulic oil supplied to the variable valve mechanism 6 is greatly reduced is learned, and a control unit that corrects a control value in the dead zone region and a learned value of the dead zone region learned by the control unit are learned. It is provided with the memory | storage part which memorize | stores the operating conditions at the time.

  In other words, the electronic control device 8 is a device that controls the hydraulic control valve 73 of the variable valve mechanism 6 described above, and the hydraulic control valve 73 is significantly slower or almost responsive to the control value than other regions. A learning unit that stores the learning value of the dead zone region that does not respond and the operating condition for learning, and the dead zone region of the hydraulic control valve 73 are learned, and the learning value and the operating condition at that time are stored in the storage unit. A control unit for controlling the control valve is provided.

  The function of the control unit is realized by the CPU 811 executing a control program, and the storage unit is configured by the RAM 813 or the EEPROM 814 described above.

  The control value is the duty value of the pulse signal described above, that is, the duty value of the pulse signal output to the linear solenoid 733 in order to determine the opening degree of the hydraulic control valve 73. That is, the control value is a duty value for duty-controlling the hydraulic control valve 73, and is calculated by PD control calculation based on the target phase and detection phase of the intake valve 23, as will be described below.

  Hereinafter, control of the hydraulic control valve 73 executed by the control unit will be described. While the engine 1 is operating, the control unit measures a current valve timing (hereinafter referred to as an actual valve timing) VTc, which is a detection phase of the intake valve 23, every predetermined time or every predetermined crank angle. Then, the hydraulic control valve 73 is feedback-controlled so that the actual valve timing matches the target valve timing VTtg that is the target phase of the intake valve 23.

Feedback control will be described. First, based on the difference ΔVT between the target valve timing VTtg calculated based on the driving state of the vehicle such as the current rotational speed of the engine 1 and the actual valve timing VTc measured by the control unit, the control unit obtains the following formula 1. Based on the PD control, the duty correction value Dr is calculated.

  In Equation 1, Kp is a proportional gain, Kd is a differential gain, and dt indicates a detection cycle.

  Next, the control unit adds the duty value Dc for maintaining the current valve timing VTc to the calculated duty correction value Dr to obtain the duty value Dn of the control signal newly output to the hydraulic control valve 73.

  Then, the control unit outputs a control signal having a duty value Dn to the linear solenoid 733 of the hydraulic control valve 73. By repeating the above processing, the hydraulic control valve 73 controls the amount of oil supplied to the advance chamber 64b and the retard chamber 64a so that the actual valve timing coincides with the target valve timing.

  The control unit increases the control gain when the calculated duty value enters the dead zone.

  This will be described in detail below. In the present embodiment, the control gain is the above-described proportional gain Kp and differential gain Kd. When the calculated duty value Dn is within the range of the dead zone, the control unit increases the proportional gain Kp and / or the differential gain Kd to be larger than when the calculated duty value Dn is outside the range of the dead zone. To do. Then, PD control based on Equation 1 is performed with the increased control gain, and the duty value Dn of the control signal newly output to the hydraulic control valve 73 is obtained.

  The ratio when increasing the control gain may be a variable value or a preset fixed value. The variable value is, for example, the calculated duty value Dn and the end of the dead zone. It is set based on the difference. Here, the end portion of the dead zone region refers to the lower end (C1 in FIG. 5) or the upper end (C2 in FIG. 5) of the dead zone.

  According to the above configuration, when the duty value is within the dead zone range, the control unit increases the control gain. Therefore, in the electronic control device 8 according to the present invention, the displacement speed of the variable valve mechanism 6 is set to the control gain. It can be faster than not changing it.

  Further, the control unit may be configured to give an offset so that the duty value is near the end of the dead zone instead of increasing the control gain.

  This will be described in detail below. When the duty value Dn calculated by the control unit is within the range of the dead band region, that is, larger than the lower dead zone region C1 and smaller than the upper dead zone region C2, the control unit will explain the duty value Dn as described below. Give an offset.

  That is, when the process of displacing the drive phase of the intake valve 23 to the advance side is being performed, the control unit adds the offset calculated by the calculation of “C2−Dn” to the control signal, so that the control signal Let C2 be the duty value. Further, when the process of displacing the drive phase of the intake valve 23 to the retard side is being performed, the control unit gives the control signal an offset calculated by the calculation of “C1−Dn”, whereby the control signal Let C1 be the duty value.

  According to the above-described configuration, when the duty value is within the range of the dead zone, the controller immediately changes the duty value to the vicinity of the end of the dead zone by applying an offset. A state in which the hydraulic control valve 73 is controlled within the range can be avoided. Therefore, the displacement speed of the variable valve mechanism 6 can be made faster than when no offset is applied.

  Hereinafter, the learning of the dead zone performed by the control unit will be described. The control unit performs the process described below to calculate the learning value of the dead zone and identify the dead zone.

  Here, the learning value is defined by the control value-displacement speed characteristic in the dead zone region obtained by linearly approximating the characteristic obtained by measuring the displacement speed of the variable valve mechanism 6 when the control value is changed.

  The control unit outputs a control signal to the linear solenoid 733 of the hydraulic control valve 73 while increasing the duty value by a constant value every predetermined time, and the displacement speed of the variable valve mechanism 6 when the control signal is each duty value. taking measurement.

  When the measured absolute value of the displacement speed changes from a state larger than a preset retarded speed threshold to a state less than the retarded speed threshold (in other words, the absolute value of the displaced speed measured before the previous time) Is larger than the retard side speed threshold, but the absolute value of the displacement speed measured this time is equal to or less than the retard side speed threshold), and the duty value at that time is the lower end of the dead zone region (C1 in FIG. 5). Judge.

  The retard side speed threshold is set to 2 to 5% of the maximum value of the displacement speed of the variable valve mechanism 6 to the retard side, for example.

  On the other hand, when the absolute value of the displacement speed changes from a state below the preset advance side speed threshold to a state greater than the advance side speed threshold (in other words, the absolute value of the displacement speed measured before the previous time is the advance angle When the absolute value of the displacement speed measured this time is larger than the advance side speed threshold), the duty value at that time is determined to be the upper end of the dead zone (C2 in FIG. 5). To do.

  The advance side speed threshold is set to 2 to 5% of the maximum value of the displacement speed of the variable valve mechanism 6 to the advance side, for example.

  And a control part prescribes | regulates a learning value with the straight line which connected the intersection P1 of duty value C1 and a retard angle side speed threshold value, and the intersection P2 of duty value C2 and an advance angle side speed threshold value, and the said learning value Is stored in the storage unit in the form of coordinate data of the intersections P1 and P2, for example.

  Note that the control unit may learn the dead zone based on the presence or absence of a sudden change in the measured displacement speed.

  This will be described in detail below. The control unit outputs a control signal to the linear solenoid 733 of the hydraulic control valve 73 while increasing the duty value by a constant value from the retard side initial value (for example, 20%) every predetermined time. The displacement speed of the variable valve mechanism 6 in the case of the value is measured, and the difference between the measured displacement speed and the previously measured displacement speed is calculated. When the displacement speed difference (absolute value) becomes smaller than a predetermined value set in advance, that is, when the displacement speed changes suddenly, the duty value at that time is the lower end of the dead zone (C1 in FIG. 5). to decide.

  Conversely, the control unit outputs a control signal to the linear solenoid 733 of the hydraulic control valve 73 while decreasing the duty value by a constant value from the advance side initial value (for example, 80%) at predetermined time intervals. , The displacement speed of the variable valve mechanism 6 at each duty value is measured, and the difference between the measured displacement speed and the previously measured displacement speed is calculated. When the displacement speed difference (absolute value) becomes smaller than a predetermined value set in advance, that is, when the displacement speed changes suddenly, the duty value at that time is the upper end of the dead zone (C2 in FIG. 5). to decide.

  In addition, the difference in the measured displacement speed changes abruptly when the control signal is output while increasing or decreasing the duty value by a certain value, because it is only twice (for example, C1 and C2 in FIG. 5). When the control signal is output while increasing the duty value by a certain value, the first sudden change may be determined as the lower end (C1 in FIG. 5), and the second sudden change may be determined as the upper end (C2 in FIG. 5). On the other hand, when the control signal is output while decreasing the duty value by a certain value, the first sudden change may be determined as the upper end (C2 in FIG. 5), and the second sudden change may be determined as the lower end (C1 in FIG. 5). . In these determinations, if there is only one sudden change, the determination may be invalidated.

  When the dead zone region is learned based on whether or not the measured displacement speed is suddenly changed, the retard side speed threshold and the advance side speed threshold are not set in advance. Therefore, the displacement speed of the variable valve mechanism 6 corresponding to the lower end (C1 in FIG. 5) of the dead zone determined by the control unit is set as the retard side speed threshold, and the upper end (in FIG. 5) of the dead zone determined by the control unit. The displacement speed of the variable valve mechanism 6 corresponding to C2) is set as the advance side speed threshold value.

  Further, the control unit stores the learning value together with the operation condition for learning when storing the learning value in the storage unit. Here, the operating conditions are defined by oil temperature or water temperature. The oil temperature is the temperature of engine oil that lubricates various bearings, various pistons, various valves, camshafts and the like in the engine 1, and the gear lubrication, the bearing lubrication, and the gear shift in the transmission having a correlation therewith. It may be the temperature of the mission oil that performs the operation or the like. The water temperature is the temperature of the cooling water for the engine 1 detected by the water temperature sensor 29. That is, substantially the same effect can be achieved by using the temperature that has a correlation with the oil temperature in various pistons.

  Further, the control unit outputs a control signal to the linear solenoid 733 of the hydraulic control valve 73 while decreasing the duty value by a constant value every predetermined time, and the displacement of the variable valve mechanism 6 when the control signal has each duty value. Speed may be measured. More specifically, when the displacement speed fluctuates from a state larger than the advance side speed threshold to a state below the advance side speed threshold, it is determined that the duty value at that time is the upper end of the dead zone region, and the displacement speed is When the state changes from a state equal to or less than the retard side speed threshold to a state greater than the retard side speed threshold, the duty value at that time is determined to be the lower end of the dead zone.

  From the above description, the control unit learns the dead zone by using the fact that the displacement speed changes suddenly at the lower limit and the upper limit of the dead zone on the control value-displacement speed characteristic shown in FIG.

  The displacement speed of the variable valve mechanism 6 is measured by the time until the variable valve mechanism 6 is displaced by a preset predetermined phase.

  The measurement of the displacement speed of the variable valve mechanism 6 will be exemplified below. A cam angle sensor for detecting the valve timing of the intake valve 23 is provided in the vicinity of the intake camshaft 235.

  As shown in FIG. 2, the cam angle sensor is connected to an intake camshaft 235 and has a rotor (not shown) having a plurality of teeth formed at equal angles on the outer periphery, and an electromagnetic pickup 237 that reads the teeth of the rotor. It consists of When the electromagnetic pickup 237 reads the teeth formed on the rotor, the angular position of the intake camshaft 235 is detected.

  The phase of the variable valve mechanism 6 is calculated based on the crank angle detected by the crank angle sensor 28 and the angular position of the intake camshaft 235 detected by the cam angle sensor.

  For example, the control unit measures the time from when the angular position of the intake camshaft 235 is input to when a crank angle of a predetermined angle before compression top dead center (BTDC) is input, and the measured time is used as an angle. By converting, the phase of the variable valve mechanism 6 is calculated.

  The control unit calculates two phases of the variable valve mechanism 6 by the above-described method. And the displacement speed of the variable valve mechanism 6 is measured by measuring the time until the variable valve mechanism 6 is displaced from one phase calculated to the other phase.

  The control unit may be configured to perform the above-described learning of the dead zone region when the vehicle is traveling, or may be configured to be performed when the vehicle is not traveling, such as when the engine is started.

  The learning of the dead zone area when the vehicle is traveling is executed as follows, for example. When the drive phase of the intake valve 23 is changed while the vehicle is running, the control unit changes the drive phase to the advance side or the retard side, so that the hydraulic oil supply flow rate set to maintain the drive phase is changed. The holding duty value (for example, about 50%) in the dead zone region where becomes substantially zero is increased when it is changed to the advance side, and is decreased when it is changed to the retard side.

  In this case, the control unit calculates the upper limit value or the lower limit value of the dead zone region by outputting the control signal while gradually increasing or decreasing the duty value as described above.

  Here, when the drive phase is changed to the predetermined phase, the characteristic until the drive phase converges to the predetermined phase is oscillatory. That is, the drive phase converges to the predetermined phase while oscillating in the advance side and the retard side from the predetermined phase.

  Therefore, the control unit calculates the upper end of the dead zone when the drive phase exceeds the predetermined phase and vibrates toward the advance angle side, and when the drive phase exceeds the predetermined phase and vibrates toward the retard side, the dead zone region The lower end of is calculated.

  The learning of the dead zone area when the vehicle is not traveling is executed as follows, for example. The control unit fixes the duty value to the retard side initial value (for example, 20%) and sets the drive phase of the intake valve 23 to the most retarded position. After that, the duty value is fixed to the advance side initial value (for example, 80%), and the drive phase is changed from the most retarded position to the predetermined phase on the advance side to measure the fluctuation speed. That is, the fluctuation speed when the duty value is 80% is measured. Then, it is determined whether or not the measured absolute value of the fluctuation speed is equal to or less than the advance side speed threshold.

  Since the duty value is maintained at 80%, the drive phase reaches the most advanced position. Thereafter, the duty value is fixed to a value (for example, 25%) larger than the initial value on the retard side by a predetermined value, and the drive phase is changed from the most advanced angle position to the predetermined phase on the retard side to measure the fluctuation speed. . That is, the fluctuation speed when the duty value is 25% is measured. Then, it is determined whether or not the measured absolute value of the fluctuation speed is equal to or smaller than the retard side speed threshold.

  Thereafter, measurement of the fluctuation speed while decreasing the duty value by a predetermined value from the advance side initial value and measurement of the fluctuation speed while increasing the duty value by a predetermined value from the retard side initial value are alternately performed. Then, in the former measurement, the duty value when the absolute value of the fluctuation speed is less than or equal to the advance side speed threshold is set as the upper end of the dead zone region, and the absolute value of the fluctuation speed is less than or equal to the retard side speed threshold. Let the duty value be the lower end of the dead zone.

  The control unit is configured to repeat the learning of the dead zone described above for each predetermined number of trips based on one trip from the start to the stop of the vehicle.

  For example, the learning control unit performs learning at a predetermined timing for each predetermined number of trips, such as trips every trip, once every trip, and once every three trips.

  Here, as the predetermined timing, for example, immediately after the start operation of the vehicle, that is, the start of the vehicle in which the starter switch or the start button is turned on, immediately before the stop of the vehicle in which the starter switch or the start button is operated off, There are timings such as when the engine 1 enters the idling state for the first time from the start of operation, when the engine 1 enters the idling state, and when the drive phase of the intake valve 23 is adjusted for the first time after the vehicle travels.

  Hereinafter, control value correction executed by the control unit will be described. When the control unit controls the variable valve mechanism 6 under an operating condition different from the operating condition for learning, the control unit corrects the learning value stored in the storage unit based on the operating condition for the control. The hydraulic control valve 73 is controlled corresponding to the dead zone region.

  That is, the control unit corrects the dead zone area stored in the storage unit based on the comparison result between the operation condition when controlling the hydraulic control valve 73 and the operation condition stored in the storage unit, The hydraulic control valve 73 is controlled based on the dead zone region.

  As an example of correction of the learning value, the control unit changes the slope of the control value-displacement speed characteristic at a ratio set according to the difference between the oil temperature or the water temperature at the time of learning and at the time of control. Correct the area.

  This will be described in detail below. In the following description, it is assumed that the control unit is configured to correct the dead zone based only on the water temperature as the operating condition.

  Map data including each value of the difference in water temperature between learning and control and a ratio set corresponding to each value is stored in the storage unit.

  The ratio is multiplied by the slope of the control value-displacement speed characteristic in the dead zone area during learning stored in the storage unit as the learning value (in other words, the slope of the straight line connecting the intersection point P1 and the intersection point P2 in FIG. 5). This is a variable for calculating a new slope.

  The map data is, for example, a ratio “1” when the difference in water temperature during learning and control is the same, and when the water temperature during control is higher than the water temperature during learning, the difference in water temperature is The ratio is configured to increase as it increases, and when the water temperature during control is lower than the water temperature during learning, the ratio is configured to decrease as the difference in water temperature increases.

  In other words, the slope in the dead zone region of the control value-displacement speed characteristic is smaller as the water temperature at the time of control is lower, based on the case where the water temperature at the time of control is the same as that at the time of learning. As the water temperature at the time of control is changed, it is changed to a larger slope.

  The control unit searches the map data based on the difference in water temperature between learning and control to calculate a ratio, and multiplies the calculated ratio by the slope of the control value-displacement speed characteristic in the dead zone when learning. Then, the control value-displacement speed characteristic in the dead zone at the time of control is calculated.

  FIG. 7 shows an example before and after the change of the slope of the control value-displacement speed characteristic in the dead zone when the water temperature at the time of control is higher than the water temperature at the time of learning. In FIG. 7, the characteristic before change is drawn with a dashed-dotted line. In addition, as a result of correcting the inclination in the dead zone region (region between the lower end C1 and the upper end C2) of the characteristic before the change, the characteristic after the change whose inclination is larger than the characteristic before the change is drawn with a solid line.

  As shown in FIG. 7, the new slope control value-displacement speed characteristic (that is, the characteristic after the change) calculated by multiplying by the ratio is the case of the middle point C3 of the lower end C1 and the upper end C2 of the dead zone. Is drawn as a straight line with zero displacement speed. The corrected characteristics are not limited to a straight line with a displacement speed of zero at the middle point C3, and may be drawn as a straight line with a displacement speed of zero when the duty value is 50%, for example.

  The control unit sets, as a new dead zone, a region where the control value-displacement speed characteristic whose inclination is changed falls within a preset displacement speed range.

  Here, the displacement speed range is a speed range between the advance side speed threshold and the retard side speed threshold shown in FIG.

  That is, as shown in FIG. 7, among the changed characteristics indicated by the solid line, a portion indicated by a thick broken line (range C ′ in the figure) within the displacement speed range is a new dead zone region. That is, the range of the dead zone of the characteristic before the change is the range from the lower end C1 to the upper end C2, whereas the range of the dead zone of the characteristic after the change is corrected from the lower end C1 ′ to the upper end C2 ′. Is done.

  According to the above-described configuration, the learning value can be corrected by a simple calculation that changes the slope in the dead zone of the control value-displacement speed characteristic.

  Further, according to the above configuration, by determining the dead zone region based on the displacement speed range, the region where the variable valve mechanism 6 has a low displacement speed is set as the dead zone region, and the variable valve mechanism 6 has a high displacement rate region. The dead zone area. Since the dead zone region is a region where the displacement speed of the variable valve mechanism 6 becomes slow, the above-described configuration is a suitable method for determining the dead zone region.

  Hereinafter, control of the variable valve mechanism 6 by the control unit will be described based on a flowchart shown in FIG. Note that the following series of processing from step SA1 to step SA10 is repeatedly executed at predetermined time intervals or at predetermined crank angles while the engine 1 is operating.

  The control unit includes a cam angle sensor for measuring the valve timing of the intake valve 23, a crank angle sensor 28, a throttle opening sensor 38, and the like for detecting the operation state of the vehicle such as the current rotational speed of the engine 1. The signals of the various sensors are read (SA1).

  The control unit calculates an actual valve timing VTc based on the detection value of the cam angle sensor (SA2). Further, the target valve timing VTtg is calculated based on the driving state of the vehicle (SA3).

  The control unit calculates a difference ΔVT between the target valve timing VTtg and the actual valve timing VTc (SA4). Then, the control unit calculates the duty correction value Dr by PD control based on the above equation 1, adds the calculated duty correction value Dr to the duty value Dc for holding the current valve timing VTc, and newly A duty value Dn of the control signal output to the hydraulic control valve 73 is calculated (SA5).

  The control unit acquires the learning value by performing learning of the dead zone region by the process of FIG. 9 described later, or corrects the learning value that has already been acquired (SA6).

  The control unit determines whether or not the duty value Dn calculated in step SA5 is within the range of the dead zone acquired or corrected in step SA6 (SA7).

  If it is within the range of the dead zone, the process of calculating a new duty value Dn by increasing the control gain at the next execution of step SA5 (SA8). Alternatively, a process of calculating a new duty value Dn is performed by giving an offset when the next step SA5 is executed (SA8).

  On the other hand, when it is outside the range of the dead zone, the process of calculating the new duty value Dn is performed without increasing the control gain or applying the offset as in step SA8 when the next step SA5 is executed. (SA9).

  Hereinafter, learning and correction of the dead zone region by the control unit will be described based on the flowchart shown in FIG.

  The control unit acquires the current operating condition (for example, the current water temperature and / or oil temperature of the engine 1) from the water temperature sensor 29 or the like (SB1).

  When the learning value of the dead zone is not stored in the storage unit (SB2), the control unit learns the dead zone based on the displacement speed of the variable valve mechanism 6 and stores it in the storage unit together with the operation condition acquired in step SB1. (SB3).

  For example, the control unit learns the dead zone region as follows. That is, a control signal is output to the hydraulic control valve 73 while increasing the duty value by a constant value every predetermined time, and the displacement speed of the variable valve mechanism 6 when the control signal is each duty value is measured. The measured absolute value of the displacement speed changes from a state larger than a preset retard angle side speed threshold value to a state less than or equal to a retard angle side speed threshold value, and less than a preset advance angle side speed threshold value. From this state, a duty value that fluctuates to a state larger than the advance side speed threshold is obtained, and a region between the obtained both duty values is set as a dead zone region.

  On the other hand, when the learning value of the dead zone is stored in the storage unit (SB2), the control unit stores the learning condition stored together with the learning value and the current condition acquired in step SB1 (that is, The dead zone region is corrected by changing the slope of the control value-displacement speed characteristic at a ratio set in accordance with the operating condition (SB4) (SB4).

  As described above, the control method according to the present invention is a control method for the hydraulic control valve 73 of the variable valve mechanism 6 that varies the operation of the intake valve 23 of the engine, and learns the dead zone region of the hydraulic control valve 73. When the hydraulic control valve 73 controls the hydraulic control valve 73 by storing the learning value of the dead zone region in which the response to the control value is significantly slower than the other region or hardly responding to the control value and the learning operation condition. In this method, the stored dead zone is corrected based on the comparison result between the operating condition and the stored operating condition, and the hydraulic control valve 73 is controlled based on the corrected dead zone.

  Hereinafter, another embodiment will be described. In the above-described embodiment, the control unit uses the control value-displacement speed characteristic of the dead zone area, which is a linear approximation of the characteristic obtained by measuring the displacement speed of the variable valve mechanism 6 when the control value is changed. As an example of the prescribed configuration, the following configuration has been described.

  That is, the control unit outputs a control signal to the linear solenoid 733 of the hydraulic control valve 73 while increasing the duty value as a control value by a constant value every predetermined time, and the variable valve when the control signal is each duty value. The displacement speed of the mechanism 6 is measured.

  Then, when the absolute value of the measured displacement speed changes from a state larger than the retard side speed threshold to a state less than or equal to the retard side speed threshold, or from a state less than the retard side speed threshold to the retard side speed threshold. When it changes to a large state, it judges that the duty value at that time is the lower end of the dead zone, and when it changes from a state below the advance side speed threshold to a state greater than the advance side speed threshold, or the advance side The configuration has been described in which, when the state changes from a state larger than the speed threshold to a state below the advance side speed threshold, the duty value at that time is determined to be the upper end of the dead zone.

  However, the control unit may be configured to define the learning value by a method other than the method shown in the above embodiment. Two types of methods will be described below.

  The first method will be described. The control unit outputs four types of duty value control signals to the linear solenoid 733 of the hydraulic control valve 73, and measures the displacement speed of the variable valve mechanism 6 at each duty value. Here, the four types of duty values are two types of duty values in which the absolute value of the displacement speed of the variable valve mechanism 6 is larger than the advance side speed threshold, and the absolute value of the displacement speed of the variable valve mechanism 6 is on the retard side. There are two types of duty values that are greater than the speed threshold. That is, as shown in FIG. 10, points P3 to P6 are calculated.

  Then, it is determined that the duty value corresponding to the intersection P1 between the straight line connecting the points P3 and P4 and the retard side speed threshold is the lower end of the dead zone region (C1 in FIG. 10). Further, it is determined that the duty value corresponding to the intersection P2 between the straight line connecting the points P5 and P6 and the advance side speed threshold is the upper end of the dead zone region (C2 in FIG. 10). And the coordinate data of intersection P1, P2 is memorize | stored in a memory | storage part as a learning value.

  The second method will be described. The control unit outputs six types of duty value control signals to the linear solenoid 733 of the hydraulic control valve 73, and measures the displacement speed of the variable valve mechanism 6 at each duty value. Here, the six kinds of duty values are two kinds of duty values in which the absolute value of the displacement speed of the variable valve mechanism 6 is larger than the advance side speed threshold, and the absolute value of the displacement speed of the variable valve mechanism 6 is on the retard side. There are two types of duty values that are larger than the speed threshold value, and two types of duty values that the absolute value of the displacement speed of the variable valve mechanism 6 is less than the advance side speed threshold value and less than the retard side speed threshold value. That is, as shown in FIG. 11, points P7 to P12 are calculated.

  Then, it is determined that the duty value corresponding to the intersection P1 between the straight line L1 connecting the points P7 and P8 and the straight line L3 connecting the points P11 and P12 is the lower end of the dead zone (C1 in FIG. 11). Further, the duty value corresponding to the intersection P2 between the straight line L2 connecting the points P9 and P10 and the straight line L3 connecting the points P11 and P12 is determined to be the upper end of the dead zone (C2 in FIG. 11). And the coordinate data of intersection P1, P2 is memorize | stored in a memory | storage part as a learning value.

  In the above-described embodiment, the electronic control device 8 includes a control unit, and a storage unit that stores the learning value of the dead zone area learned by the control unit and the operation condition at the time of learning. In the case where the variable valve mechanism 6 is controlled under an operating condition different from the operating condition, the configuration has been described in which the learning value stored in the storage unit is corrected based on the operating condition for the control.

  However, the electronic control unit 8 drives the intake valve 23 with respect to the variable valve mechanism 6 that can adjust the drive phase of the intake valve 23 relative to the rotational phase of the crankshaft 25 by hydraulically driving the hydraulic control valve 73. The hydraulic control valve 73 is controlled based on the control value for adjusting the phase to the target phase, and the dead zone region where the flow rate of the hydraulic oil supplied to the variable valve mechanism 6 is greatly reduced with respect to the control value is learned. A control unit that corrects a control value in the dead zone region is provided, and a storage unit that stores a learned value of the dead zone region learned in the control unit is provided for each learning region that is preliminarily classified based on operating conditions, and is controlled. When the variable valve mechanism 6 is controlled, the unit recognizes the dead zone based on the learning value corresponding to the operation condition from the storage unit, and corrects the control value in the dead zone. It may be.

  This will be described in detail below. The electronic control unit 8 has a total m × n of a plurality of learning areas, for example, m areas TA1 to TAm based on the water temperature of the engine 1 and n areas TB1 to TBn based on the oil temperature of the engine 1. A temperature region composed of regions is set, and the upper and lower ends of the dead zone as learning values for each temperature region are stored in the storage unit of the electronic control device 8. An example of two-dimensional map data for setting a learning value for each temperature region described above is shown in FIG.

  Note that the plurality of learning regions to be set are not limited to the temperature region based on the water temperature and oil temperature of the engine 1, and for example, as illustrated in FIG. 12B, a one-dimensional map based only on the water temperature of the engine 1. It may be a temperature range set as data.

  Further, even when the control unit is configured to learn the dead zone of the hydraulic control valve 73 for each of the plurality of learning zones, the control unit learns the dead zone for the vehicle as in the above-described embodiment. You may comprise so that it may repeat for every predetermined number of trips on the basis of one trip from an operation start to a stop.

  In this case, the configuration may be such that the dead zone region of the hydraulic control valve 73 in the temperature region that cannot be learned in a certain trip is learned in the subsequent trip. Further, the control unit may be configured to learn a dead zone in an unlearned temperature region when the engine 1 is idling.

  As described in the above embodiment, the control unit performs learning of the dead zone, and includes the water temperature and the oil temperature of the engine 1 when learning the values of the upper and lower ends of the dead zone specified by the learning. As a learned value of the temperature region to be stored, it is stored in the storage unit.

  In the case where the water temperature or oil temperature of the engine 1 is the water temperature or oil temperature in the temperature range in which the learning value is already stored in the storage unit, the control of the hydraulic control valve 73 is executed by the control unit. The control unit may be configured to perform learning of the dead zone and overwrite a new learning value in the storage unit, or may be configured to execute only control of the hydraulic control valve 73 without performing learning of the dead zone. There may be.

  According to the above-described configuration, the control unit specifies a different dead zone for each temperature region. Therefore, even if the dead zone varies depending on the temperature as shown in FIG. 1A, the dead zone can be accurately specified. it can.

  When the control unit controls the variable valve mechanism 6 and the learning region corresponding to the operation condition is not learned, the control unit corresponds to the learning region based on the learning value of the already learned region near the learning region. A configuration for estimating the dead zone region may be used.

  The dead zone region is estimated by, for example, the following calculation. As a first example, in FIG. 12A, a temperature region composed of TA1 and TB2 (hereinafter referred to as temperature region A1B2) is a learned region, and a temperature region composed of TA1 and TBn (hereinafter referred to as temperature region A1Bn). (2) is an unlearned region, the dead zone region of the unlearned region is estimated by correcting the already learned region by the method described in the above embodiment.

  Specifically, by changing the slope of the control value-displacement speed characteristic based on the learning value of the temperature region A1B2 at a ratio set according to the difference between the water temperature and the oil temperature of the temperature region A1B2 and the temperature region A1Bn, The dead zone region of the temperature region A1Bn is estimated.

  As a second example, when the temperature region composed of TA1 and TB2 and the temperature region composed of TA3 and TB2 are learned regions, and the temperature region composed of TA2 and TB2 is an unlearned region, learning values of two learned regions Is estimated as the dead zone area of the unlearned area.

  According to the above-described configuration, when the control unit learns the dead zone region in one temperature region, the dead zone region of another temperature region is calculated based on the learned dead zone region. There is no need to learn.

  Hereinafter, learning and correction of the dead zone by the control unit in the case where the electronic control unit 8 is configured to include a storage unit that stores a learning value for each learning region that is preliminarily classified based on the operating conditions is illustrated in FIG. 13. This will be described based on a flowchart.

  The control unit acquires the current operating condition (for example, the current water temperature of the engine 1) from the water temperature sensor 29 or the like (SC1).

  When the learning value is not stored in the storage unit in all learning regions (that is, the temperature region) (SC2), the control unit learns the dead zone region and learns the dead zone region in the same manner as in step SB3 in FIG. Is stored in the storage unit as a learned value of the temperature region corresponding to the water temperature acquired in step SC1, and the learned value is set as a dead zone region used for control of the variable valve mechanism 6 (SC3).

  The dead zone area learned in step SC3 is stored as a learned value corresponding to the temperature area specified according to the procedure shown in FIG.

  On the other hand, when the learning value is stored in the storage unit in any temperature region (SC2), the control unit corresponds to the water temperature acquired in step SC1 (hereinafter referred to as the current temperature region). It is determined whether a learning value is stored in (SC4).

  When the learning value is stored in the temperature region corresponding to the water temperature acquired in step SC1 in step SC4, the control unit sets the learning value as a dead zone region used for control of the variable valve mechanism 6 (SC5).

  On the other hand, when the learning value is not stored in the temperature region corresponding to the water temperature acquired in step SC1 in step SC4, the control unit learns the learning value of another temperature region already stored in the vicinity of the current temperature region. Based on the above, the dead zone region of the current temperature region is estimated, the estimated dead zone region is stored in the storage unit as the learned value of the temperature region corresponding to the water temperature acquired in step SC1, and the learned value is stored in the variable valve mechanism 6 A dead zone region used for the control of the image (SC6).

  Hereinafter, the process which specifies a temperature area | region is demonstrated based on the flowchart shown in FIG. In this description, it is assumed that the set temperature regions are the one-dimensional map data shown in FIG.

  When the dead zone region is learned in step SC3 in FIG. 13 (SD1), the control unit specifies a temperature region in which the learned dead zone region is stored based on the water temperature acquired in step SC1 in FIG.

  That is, when the water temperature is lower than the boundary temperature TE1 shown in FIG. 12B (SD2), the learned dead zone area is stored as the dead zone area of the temperature zone TC1 (SD3), and the water temperature is higher than the boundary temperature TE1 and higher than the boundary temperature TE2. When the temperature is low (SD4), the learned dead zone region is stored as the dead zone of the temperature region TC2 (SD5). When the water temperature is equal to or higher than the boundary temperature TE2 and lower than the boundary temperature TE3 (SD6), the learned dead zone region is stored in the temperature region TC3. Store as a dead zone area (SD7).

  Although not shown, the control unit determines a temperature region in which the learned dead zone region is stored based on a preset boundary temperature (eg, TEm) even when the water temperature is equal to or higher than the boundary temperature TE3. .

  In the above-described embodiment, the configuration in which the engine 1 to which the electronic control device 8 is applied is provided with the variable valve mechanism 6 only on the intake valve 23 side is not limited to such a configuration.

  For example, the engine 1 has a configuration in which the variable valve mechanism 6 is provided on the exhaust valve 24 side instead of the intake valve 23 side, or a configuration in which the variable valve timing mechanism 6 is provided on both sides of the intake valve 23 and the exhaust valve 24. May be.

  Note that the above-described embodiment is merely an example of the present invention, and it is needless to say that the specific configuration of each block can be changed and designed as appropriate within the scope of the effects of the present invention.

(A) is a characteristic diagram of the displacement speed of the variable valve mechanism with respect to the duty value of the control signal in which the dead zone is different depending on the oil temperature, and (b) is the displacement speed of the variable valve mechanism with respect to the duty value of the control signal in which the dead zone is different depending on the part. Characteristics chart Illustration of the engine (A) External view of variable valve mechanism and intake camshaft, (b) External view of variable valve mechanism (A) is an explanatory diagram showing the state of the hydraulic control valve when the duty value is about 100%, (b) is an explanatory diagram showing the state of the hydraulic control valve when the duty value is about 0%, (c) Explanatory drawing showing the state of the hydraulic control valve when the duty value is about 50% Explanatory drawing which shows the displacement speed of the variable valve mechanism with respect to the duty value of a control signal Functional block diagram of an electronic control unit for engine control Explanatory drawing about change in slope of control value-displacement speed characteristics Flowchart for explaining control of variable valve mechanism by control unit Flowchart for explaining learning and correction of dead zone by control unit Explanatory drawing of calculation of dead zone based on control signals of four types of duty values Explanatory diagram of calculation of dead zone based on control signals of six types of duty values (A) is explanatory drawing which shows the two-dimensional map data which divided the learning area | region based on engine water temperature and oil temperature, (b) is explanatory drawing which shows the one-dimensional map data which divided the learning area | region based on engine water temperature Flowchart for explaining learning and estimation of dead zone by control unit in another embodiment Flowchart for explaining processing for specifying a learning area

Explanation of symbols

6: Variable valve mechanism 8: Electronic control unit 23: Valve (intake valve)
25: Crankshaft 73: Drive hydraulic valve (hydraulic control valve)

Claims (5)

An electronic control device for controlling a drive hydraulic valve of a variable valve mechanism that varies the operation of an intake valve and / or an exhaust valve of an internal combustion engine,
A storage unit in which a learning value of a dead zone region in which the driving hydraulic valve is responsive to a control value is significantly slower than the other region or hardly responds and an operation condition at the time of learning are stored;
While learning the dead zone region of the drive hydraulic valve, the learning value and operating conditions at that time are stored in the storage unit,
Based on the comparison result of the operating condition when controlling the drive hydraulic valve and the operating condition stored in the storage unit, the dead zone region stored in the storage unit is corrected, and the corrected dead zone region is used. An electronic control device comprising a control unit for controlling the drive hydraulic valve. The operating value is defined by a control value-displacement speed characteristic of a dead zone region obtained by linear approximation of a characteristic obtained by measuring the displacement speed of the variable valve mechanism when the learning value changes the control value. It is defined by the oil temperature or water temperature when learning,
The control unit corrects the dead zone region by changing the slope of the control value-displacement speed characteristic at a ratio set according to the difference between the oil temperature or the water temperature at the time of learning and at the time of control. The electronic control device according to claim 1, wherein   3. The electronic control device according to claim 2, wherein the control unit sets a new dead zone region in a region where the control value-displacement speed characteristic whose inclination is changed falls within a preset displacement speed range. The control value is a duty value for duty-controlling the drive hydraulic valve, calculated by a PD control calculation based on a target phase and a detection phase of the intake valve and / or the exhaust valve;
The control unit increases the control gain when the calculated duty value enters the dead band region, or gives an offset so that the duty value is near the end of the dead band region. 4. The electronic control device according to any one of 3. A control method for a drive hydraulic valve of a variable valve mechanism that varies the operation of an intake valve and / or an exhaust valve of an internal combustion engine,
Learning the dead zone region of the drive hydraulic valve, the learning value of the dead zone region in which the drive hydraulic valve is significantly slower or less responsive to the control value than other regions, and the operating conditions for learning Remember,
A control method for correcting the stored dead zone based on the comparison result between the operating conditions for controlling the drive hydraulic valve and the stored operating conditions, and controlling the drive hydraulic valve based on the corrected dead zone .