JP2017180240A - Control device for variable displacement oil pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve controllability of feedback control in a hydraulic system provided with a variable displacement oil pump.SOLUTION: A control device of an oil pump includes a control part (controller 100) configured so as to control the oil pump while changing capacity of an oil pump 36 such that a hydraulic pressure of a hydraulic passage gets to a target hydraulic pressure. The control part has a linear solenoid valve 49 and changes the capacity of the oil pump by changing a duty ratio of a control signal supplied to the solenoid valve. The linear solenoid valve has such characteristics that a passage flow rate performs a prescribed change with respect to the change of the duty ratio in a prescribed use duty range and the control part supplies the control signal in the use duty range on the basis of a characteristic table of the linear solenoid valve. The control part performs such a learning correction as to offset the characteristic table of the linear solenoid valve on the basis of a pressure change of a hydraulic passage detected by an oil pressure sensor 70.SELECTED DRAWING: Figure 2

Description

  The technology disclosed herein relates to a control device for a variable displacement oil pump.

  Patent Document 1 discloses a configuration in which oil is supplied via a hydraulic path to an oil hydraulic unit of an engine such as a variable valve timing mechanism or a lubricating portion such as an engine crankshaft by a variable displacement oil pump. Has been. By configuring the oil pump as a variable displacement type, it is possible to avoid unnecessary driving of the oil pump and improve fuel consumption.

  Specifically, the variable displacement oil pump described in Patent Document 1 has a pressure chamber to which oil is supplied, and is configured such that the capacity changes by adjusting the hydraulic pressure supplied to the pressure chamber. Yes. The hydraulic pressure supplied to the pressure chamber is adjusted by controlling the flow rate that branches from the middle of the hydraulic path and passes through a linear solenoid valve that is connected to the oil passage connected to the pressure chamber of the variable displacement oil pump. Is done. The controller changes the passage flow rate by changing the duty ratio of the control signal supplied to the linear solenoid valve based on the hydraulic pressure of the hydraulic path detected by the hydraulic sensor. The controller performs feedback control so that the hydraulic pressure in the hydraulic path becomes the target hydraulic pressure.

JP 2015-45288 A

  By the way, in the linear solenoid valve, in the predetermined duty range on the center side, the passing flow rate changes relatively slowly with respect to the change of the duty ratio (that is, the flow rate with the horizontal axis being the duty ratio and the vertical axis being the passing flow rate. On the other hand, when the duty ratio is lower than the predetermined duty range and when the duty ratio is higher than the predetermined duty range, the passage flow rate is predetermined with respect to the change of the duty ratio. In some cases, the flow rate does not change (for example, even if the duty ratio is changed, the passing flow rate hardly changes and the gradient is almost zero in the flow rate characteristic line).

  When hydraulic feedback control is performed using a linear solenoid valve having such characteristics, a characteristic table indicating the characteristics of the linear solenoid valve is prepared in advance, and the linear solenoid valve is controlled within a predetermined duty range based on the characteristic table. It is conceivable to supply a signal. As a result, the flow rate of the linear solenoid valve can be adjusted with relatively high accuracy, and the controllability of the hydraulic feedback control is enhanced.

  However, if the characteristics of the linear solenoid valve differ greatly due to individual differences of the linear solenoid valve, even if the linear solenoid valve is controlled within a predetermined duty range, the flow rate of the linear solenoid valve deviates from the target flow rate. There is a case. As a result, the controllability of the hydraulic feedback control may deteriorate (for example, the responsiveness may decrease).

  The technology disclosed herein has been made in view of such a point, and an object thereof is to improve the controllability of feedback control in a hydraulic system including a variable displacement oil pump.

  The inventor of the present application paid attention to the fact that the change characteristic of the passage flow rate greatly changes with the change of the duty ratio in the vicinity of the lower limit and the upper limit of the linear solenoid valve in the predetermined duty range. In other words, if a linear solenoid valve is controlled within a predetermined duty range based on a predetermined characteristic table, if the difference between the actual characteristic of the linear solenoid valve and the characteristic table is small, it will pass with respect to the change in duty ratio. The change characteristics of the flow rate do not change significantly. However, when there is a large difference between the actual characteristics of the linear solenoid valve and the characteristic table, when the linear solenoid valve is controlled within a predetermined duty range, the change characteristic of the passing flow rate with respect to the change of the duty ratio is Major changes can occur.

  When the change characteristic of the passage flow rate of the linear solenoid valve changes greatly, the hydraulic pressure of the hydraulic path through which the hydraulic pressure is supplied from the variable displacement oil pump also varies greatly.

  In view of this, the inventors of the present application performed learning correction for offsetting the characteristic table so that the difference between the actual characteristic of the linear solenoid valve and the characteristic table becomes small based on the pressure change in the hydraulic path.

  Specifically, the technology disclosed herein detects an oil pump having a variable capacity, a hydraulic actuator connected to the oil pump via a hydraulic path, and a hydraulic pressure of the hydraulic path. And a control unit configured to control the oil pump while changing the capacity of the oil pump so that the hydraulic pressure in the hydraulic path becomes a target hydraulic pressure.

  The control unit has a linear solenoid valve that controls the hydraulic pressure supplied to the pressure chamber of the oil pump, and changes the duty ratio of the control signal supplied to the linear solenoid valve, thereby changing the pressure of the oil pump. The oil pressure supplied to the chamber is changed to change the capacity of the oil pump, and the linear solenoid valve has a predetermined flow rate change with respect to a change of the duty ratio in a predetermined duty range. When the duty ratio is lower than the use duty range, and when the duty ratio is higher than the use duty range, the flow rate does not change with respect to the change of the duty ratio, The control unit also controls the characteristics of the linear solenoid valve. The control unit is configured to supply a control signal to the linear solenoid valve in the duty cycle range based on a table, and the control unit further includes the linear solenoid based on a pressure change of the hydraulic path detected by the hydraulic sensor. The learning correction is performed to offset the valve characteristic table.

  According to this configuration, the control unit adjusts the flow rate of the linear solenoid valve to change the capacity of the oil pump by changing the duty ratio of the control signal supplied to the linear solenoid valve. The control unit performs feedback control based on the hydraulic pressure detected by the hydraulic sensor so that the hydraulic pressure in the hydraulic path becomes the target hydraulic pressure by controlling the oil pump while changing the capacity of the oil pump.

  The linear solenoid valve has such a characteristic that the passage flow rate changes with respect to the change of the duty ratio within a predetermined duty range in the center, and the control unit is based on a characteristic table representing the characteristic. The control signal is supplied to the linear solenoid valve.

  Here, due to individual differences of the linear solenoid valves, if the actual characteristics in the operating duty range are different from the characteristic table, the actual passing flow rate of the linear solenoid valve is different from the passing flow rate in the characteristic table. Therefore, the hydraulic pressure of the hydraulic path is also different from the target hydraulic pressure. Specifically, by changing the duty ratio, the hydraulic pressure in the hydraulic path should increase or decrease, but the hydraulic pressure does not change or the hydraulic pressure in the hydraulic path should not change significantly. It will change greatly.

  The control unit determines whether or not the actual characteristics of the linear solenoid valve are different from the characteristic table used for controlling the linear solenoid valve based on the pressure change of the hydraulic path based on the detection of the hydraulic sensor. If they are different, learning correction for offsetting the characteristic table of the linear solenoid valve is performed. By doing so, the difference between the actual characteristic of the linear solenoid valve and the characteristic table used for the control of the linear solenoid valve is reduced or eliminated, so that the controllability of the feedback control is improved.

  Further, by using a hydraulic sensor used for feedback control, separate hardware for performing learning correction becomes unnecessary.

  The control unit may perform the learning correction when a hydraulic pressure detected by the hydraulic pressure sensor is deviated from a target hydraulic pressure when a condition for executing the learning correction is satisfied.

  By performing learning correction based on the deviation between the detected hydraulic pressure and the target hydraulic pressure when a condition for executing preset learning correction is established, it is possible to perform highly accurate learning control.

  The control unit may perform the learning correction when the oil temperature is in a predetermined range.

  If the oil temperature is too low or too high, the kinematic viscosity of the oil may be too high or too low, and the change in oil pressure detected by the oil pressure sensor may become unstable. Therefore, it is preferable to perform learning correction when the oil temperature is within a predetermined range that is neither too low nor too high so that the accuracy of learning correction based on detection by the hydraulic sensor does not decrease.

  The control unit may perform the learning correction when a duty ratio of a control signal supplied to the linear solenoid valve is within a predetermined learning range.

  As described above, when the duty ratio is low or the duty ratio is high, the linear solenoid valve has a characteristic that the passing flow rate does not change with respect to the change of the duty ratio. In this case, it is impossible to accurately grasp the actual characteristics of the linear solenoid valve. Therefore, by performing the learning correction when the duty ratio of the control signal is within a predetermined learning range, the accuracy of the learning correction is increased. The predetermined learning range may be the same as the use duty range described above, or may be a range narrower than the use duty range.

  The control unit may prohibit the learning correction when a shift in hydraulic pressure detected by the hydraulic sensor exceeds a preset upper limit value and lower limit value.

  A hydraulic actuator is connected to the hydraulic path, and the hydraulic pressure in the hydraulic path can vary greatly depending on the operating state (including non-operation) of the hydraulic actuator. Depending on the operating state of the hydraulic actuator, the hydraulic pressure detected by the hydraulic sensor may temporarily fluctuate greatly. In this case, if the learning correction of the characteristic table is performed based on the temporary increase in the deviation, the accuracy of the learning correction is reduced. Therefore, when the deviation of the hydraulic pressure detected by the hydraulic sensor exceeds a preset upper limit value and lower limit value, it is possible to increase the accuracy of learning correction by prohibiting learning correction.

  Here, the upper limit value and the lower limit value may be set based on, for example, the upper limit standard and the lower limit standard of the linear solenoid valve. That is, the learning correction may not be performed when a hydraulic pressure deviation that exceeds the individual difference of the linear solenoid valves occurs.

  The oil pump may be driven by an engine mounted on an automobile, and the control unit may prohibit the learning correction when a change in rotation of the engine is equal to or greater than a predetermined value.

  The oil pump driven by the engine changes the discharge amount according to the engine rotation. The control unit controls to suppress the change in hydraulic pressure at that time, but after the change in rotation is detected, the duty ratio is controlled and the flow rate of the linear solenoid valve is adjusted to suppress the change in hydraulic pressure. When the engine changes suddenly due to acceleration or shift change that greatly depresses, the oil pressure tends to change. If learning correction is performed at this time, the accuracy of learning correction is reduced as described above. Therefore, the accuracy of learning correction can be improved by prohibiting the learning correction when the engine rotation change is greater than or equal to a predetermined value.

  The oil pump is driven by an engine mounted on an automobile, and the hydraulic operation device operates at least one of an intake valve and an exhaust valve so as to deactivate a part of a plurality of cylinders of the engine. A valve stop device configured to stop the operation may be included.

  Since the valve stop device switches between the operation and stop of the intake valve and / or the exhaust valve according to the operating state of the engine, high responsiveness is required. During operation of the valve stop device, the hydraulic pressure in the hydraulic path must also be changed with high responsiveness. As described above, by learning and correcting the characteristic table of the linear solenoid valve, the linear solenoid valve can be controlled based on actual characteristics or characteristics close to actual characteristics. Controllability, that is, control responsiveness can be improved, and high responsiveness required for the hydraulic system can be satisfied.

  As described above, according to the control device for the variable displacement oil pump, the actual characteristics of the linear solenoid valve and the control of the linear solenoid valve are used based on the pressure change of the hydraulic path detected by the hydraulic sensor. When it is determined that the characteristic table is different, the learning control for offsetting the characteristic table of the linear solenoid valve is performed to improve the controllability of the feedback control.

FIG. 1 is a cross-sectional view showing a schematic configuration of a multi-cylinder engine to which a control device for a variable displacement oil pump is applied. FIG. 2 is a diagram showing a schematic configuration of the hydraulic system. FIG. 3 is a diagram showing the characteristics of the variable displacement oil pump. The upper diagram of FIG. 4 illustrates a characteristic line (characteristic table) illustrating the change of the flow rate of the linear solenoid valve with respect to the change of the duty ratio, and the lower diagram of FIG. 4 illustrates the change of the oil pressure of the oil supply passage with respect to the change of the duty ratio. It is a figure to do. FIG. 5 is a diagram illustrating individual differences in characteristic lines of the linear solenoid valve. FIG. 6 is a flowchart showing a learning procedure of the characteristic table of the linear solenoid valve.

  Hereinafter, the control apparatus for the variable displacement oil pump disclosed herein will be described in detail with reference to the drawings. In addition, the following description is an illustration. FIG. 1 shows a multi-cylinder engine 2 (hereinafter simply referred to as an engine 2) to which a control device for a variable displacement oil pump is applied. The engine 2 is an in-line four-cylinder gasoline engine in which first to fourth cylinders are sequentially arranged in series in a direction perpendicular to the plane of FIG. 1 and is mounted on a vehicle such as a four-wheeled vehicle. In the engine 2, a cam cap 3, a cylinder head 4, a cylinder block 5, a crankcase (not shown), and an oil pan 6 (see FIG. 2) are connected to each other in the four cylinder bores 7 formed in the cylinder block 5. Are connected to each other by a connecting rod 10, and a combustion chamber 11 is connected by a cylinder bore 7, a piston 8, and a cylinder head 4 of the cylinder block 5. Is formed for each cylinder.

  The cylinder head 4 is provided with an intake port 12 and an exhaust port 13 that open to the combustion chamber 11, and an intake valve 14 and an exhaust valve 15 that open and close the intake port 12 and the exhaust port 13, respectively. Equipped. The intake valve 14 and the exhaust valve 15 are urged in the closing direction (upward in FIG. 1) by return springs 16 and 17, respectively, and cam portions 18a and 19a provided on the outer periphery of the rotating camshafts 18 and 19, respectively. Cam followers 20a and 21a provided rotatably at substantially central portions of the swing arms 20 and 21 are pushed downward, and the swing arm is supported with the top of the pivot mechanism provided on one end side of the swing arms 20 and 21 as a fulcrum. 20 and 21 are configured such that the intake valve 14 and the exhaust valve 15 are pushed downward to open against the urging force of the return springs 16 and 17 at the other end of the swing arms 20 and 21 by swinging. Has been.

  As a pivot mechanism of the swing arms 20 and 21 of the second and third cylinders located in the center of the engine 2 in the cylinder row direction (same configuration as the pivot mechanism of the HLA 25 described later), the valve clearance is automatically zeroed by hydraulic pressure. A known hydraulic lash adjuster 24 (hereinafter referred to as an HLA 24 using an abbreviation of “Hydraulic Lash Adjuster”) is provided. The HLA 24 is shown only in FIG.

  Moreover, HLA25 with a valve stop mechanism provided with a pivot mechanism is provided with respect to the swing arms 20 and 21 of the first and fourth cylinders located at both ends of the engine 2 in the cylinder row direction. Although the detailed illustration is omitted, the HLA 25 with a valve stop mechanism is a part of all cylinders in the engine 2 in addition to the pivot mechanism configured to be able to automatically adjust the valve clearance to zero like the HLA 24. During the reduced-cylinder operation in which the operation of certain first and fourth cylinders (corresponding to specific cylinders) is stopped, the intake and exhaust valves 14 and 15 of the first and fourth cylinders are stopped (open / close operation is stopped), while all cylinders When all cylinders are operated to operate (four cylinders), a valve stop mechanism that operates (opens and closes) the intake and exhaust valves 14 and 15 of the first and fourth cylinders is provided. The intake and exhaust valves 14 and 15 of the second and third cylinders are operated during both the reduced cylinder operation and the all cylinder operation. Therefore, during the reduced cylinder operation, the intake and exhaust valves 14 and 15 of only the first and fourth cylinders of all the cylinders of the engine 2 are deactivated. During the full cylinder operation, the intake and exhaust valves 14 and 15 of all the cylinders are activated. Will do. Note that the reduced cylinder operation and the all cylinder operation are switched according to the operating state of the engine 2 as described later. Each of the HLAs 24 and 25 is included in a hydraulic actuator.

  Mounting holes 26 and 27 for inserting and mounting the lower end portion of the HLA 25 with a valve stop mechanism are provided in portions on the intake side and exhaust side corresponding to the first and fourth cylinders in the cylinder head 4, respectively. Yes. In addition, mounting holes similar to the mounting holes 26 and 27 for inserting and mounting the lower end portion of the HLA 24 are provided in portions on the intake side and the exhaust side corresponding to the second and third cylinders in the cylinder head 4. Is provided. Further, the cylinder head 4 is provided with two oil passages 61, 63; 62, 64 communicating with the mounting holes 26, 27 for the HLA 25 with a valve stop mechanism, respectively. The oil passages 61 and 62 supply hydraulic pressure (operating pressure) for operating the valve stop mechanism in the HLA 25 with a valve stop mechanism, and the oil passages 63 and 64 have a valve stop mechanism. The pivot mechanism of the HLA 25 is configured to supply a hydraulic pressure for automatically adjusting the valve clearance to zero. Note that only the oil passages 63 and 64 communicate with the mounting holes for the HLA 24. The oil passages 61 to 64 will be described in detail later with reference to FIG.

  The cylinder block 5 is provided with a main gallery 54 that extends in the cylinder row direction in the side wall on the exhaust side of the cylinder bore 7. An oil jet 28 (oil injection valve) for cooling the piston communicating with the main gallery 54 is provided for each piston 8 in the vicinity of the lower side of the main gallery 54. The oil jet 28 has a nozzle portion 28a disposed on the lower side of the piston 8 and injects engine oil (hereinafter simply referred to as oil) from the nozzle portion 28a toward the back surface of the top portion of the piston 8. It is configured as follows.

  Above each camshaft 18, 19, oil showers 29, 30 formed of pipes are provided, and oil for lubrication from the oil showers 29, 30 is placed below the camshafts 18, 19. The cam portions 18a and 19a, and the contact portions between the swing arms 20 and 21 and the cam followers 20a and 21a, which are located further below, are configured to drop.

  Although not shown in FIG. 1, a hydraulically operated valve characteristic that changes the valve characteristic of at least one of the intake valve 14 and the exhaust valve 15 (both in the present embodiment) by hydraulic operation in all cylinders of the engine 2. Variable valve timing mechanisms 32 and 33 (hereinafter simply referred to as VVT) as change devices are provided (see FIG. 2). VVT32 is an intake-side VVT, and VVT33 is an exhaust-side VVT. Similarly to the HLA 24 and 25, the VVTs 32 and 33 are hydraulic actuators, and since the configuration thereof is known, the description thereof is omitted. However, the VVTs 32 and 33 are respectively advanced hydraulic chambers 326 and 336 and retarded hydraulic chambers. By supplying and discharging hydraulic pressure to and from 325 and 335, the rotational phase of the camshafts 18 and 19 is shifted with respect to the rotational phase of the crankshaft 9, and the valve opening phases of the intake valve 14 and the exhaust valve 15 are made to advance and retard. Change to the angular direction.

  Next, the hydraulic system 1 for supplying oil to the engine 2 will be described in detail with reference to FIG. As shown in the figure, the hydraulic system 1 is connected to the variable displacement oil pump 36 (hereinafter referred to as an oil pump 36) driven by the rotation of the crankshaft 9 and is boosted by the oil pump 36. An oil supply path 50 (hydraulic path) for guiding oil to the lubrication part of the engine 2 and the hydraulic actuator is provided. The oil pump 36 is an auxiliary machine that is driven by the engine 2.

  The oil supply passage 50 includes a passage formed in a pipe, the cylinder head 4, the cylinder block 5, or the like. The oil supply passage 50 communicates with the oil pump 36, and a first communication path 51 extending from the oil pump 36 (details will be described later as a discharge port 361 b) to a branch point 54 a in the cylinder block 5, and a cylinder in the cylinder block 5. The main gallery 54 extending in the column direction, the second communication path 52 extending from the branch point 54b on the main gallery 54 to the cylinder head 4, and the space between the intake side and the exhaust side in the cylinder head 4 are substantially horizontal. A third communication passage 53 that extends and a plurality of oil passages 61 to 69 that branch from the third communication passage 53 in the cylinder head 4 are provided.

  The oil pump 36 is a known variable displacement oil pump that changes the capacity of the oil pump 36 to vary the oil discharge amount of the oil pump 36, and is formed so that one end side is open and the inside is a cross section. A housing 361 comprising a pump body having a pump housing chamber formed of a circular space, and a cover member for closing the one end opening of the pump body; and a substantially center of the pump housing chamber supported rotatably by the housing 361 A drive shaft 362 that passes through the shaft and is rotationally driven by the crankshaft 9, a rotor 363 that is rotatably accommodated in the pump housing chamber and has a central portion coupled to the drive shaft 362, and a radially outer portion of the rotor 363. A pump element comprising a vane 364, which is housed in a plurality of slits formed in a notch in each of the slits. A cam ring 366 that is arranged eccentrically with respect to the rotation center of the rotor 363 and defines a pump chamber 365 that is a plurality of hydraulic oil chambers together with the rotor 363 and the adjacent vanes 364, and the pump body. A spring 367 that is a biasing member that constantly biases the cam ring 366 toward the side where the eccentric amount of the cam ring 366 relative to the rotation center of the rotor 363 increases, and is slidably disposed on both sides on the inner peripheral side of the rotor 363. And a pair of ring members 368 having a smaller diameter than the rotor 363. The housing 361 includes a suction port 361 a that supplies oil to the internal pump chamber 365 and a discharge port 361 b that discharges oil from the pump chamber 365. A pressure chamber 369 defined by the inner peripheral surface of the housing 361 and the outer peripheral surface of the cam ring 366 is formed in the housing 361, and an introduction hole 369 a that opens to the pressure chamber 369 is provided. The oil pump 36 introduces oil into the pressure chamber 369 from the introduction hole 369a, so that the cam ring 366 swings with respect to the fulcrum 361c, and the rotor 363 is eccentric relative to the cam ring 366. The discharge capacity is changed.

  An oil strainer 39 facing the oil pan 6 is connected to the suction port 361 a of the oil pump 36. In the first communication path 51 communicating with the discharge port 361b of the oil pump 36, an oil filter 37 and an oil cooler 38 are arranged in order from the upstream side to the downstream side, and the oil stored in the oil pan 6 is After being pumped up by an oil pump 36 through an oil strainer 39, it is filtered by an oil filter 37 and cooled by an oil cooler 38 before being introduced into a main gallery 54 in the cylinder block 5.

  The main gallery 54 supplies oil to metal bearings disposed in the oil jet 28 for injecting cooling oil to the back side of the four pistons 8 and five main journals for rotatably supporting the crankshaft 9. Is connected to the oil supply part 42 of the metal bearing disposed on the crank pin of the crankshaft 9 that rotatably connects the four connecting rods, and oil is constantly supplied to the main gallery 54. The

  On the downstream side of the branch point 54 c on the main gallery 54, oil is supplied from the introduction hole 369 a to the oil supply portion 43 that supplies oil to the hydraulic chain tensioner and the pressure chamber 369 of the oil pump 36 via the linear solenoid valve 49. An oil passage 40 to be supplied is connected.

  The oil passage 68 branched from the branch point 53a of the third communication passage 53 is connected to the advance hydraulic chamber 336 of the exhaust side VVT 33 for changing the opening / closing timing of the exhaust valve 15 via the exhaust side first direction switching valve 35, and It is connected to the retarded hydraulic chamber 335 and is configured to supply oil by controlling the first direction switching valve 35. The oil passage 64 branched from the branch point 53a includes a metal bearing oil supply unit 45 (see the white triangle in FIG. 2) disposed in the cam journal of the exhaust camshaft 19 and the HLA 24 (see FIG. 2). 2) and an HLA 25 with a valve stop mechanism (see the white oval in FIG. 2). The oil passage 64 is always supplied with oil. Further, the oil passage 66 that branches from the branch point 64a of the oil passage 64 is connected to an oil shower 30 that supplies lubricating oil to the swing arm 21 on the exhaust side, and oil is constantly supplied to the oil passage 66. The

  The intake side is the same as the exhaust side, and the oil passage 67 branched from the branch point 53c of the third communication passage 53 changes the opening / closing timing of the intake valve 14 via the intake side first direction switching valve 34. The VVT 32 is connected to the advance hydraulic chamber 326 and the retard hydraulic chamber 325. Further, the oil passage 63 branched from the branch point 53d includes a metal bearing oil supply unit 44 (see the white triangle in FIG. 2) disposed in the cam journal of the intake side camshaft 18 and the HLA 24 (see FIG. 2). And a HLA 25 with a valve stop mechanism (see a white oval in FIG. 2). Further, the oil passage 65 branched from the branch point 63a of the oil passage 63 is connected to an oil shower 29 that supplies lubricating oil to the swing arm 20 on the intake side.

  Further, the oil passage 69 branched from the branch point 53c of the third communication passage 53 has a check valve 48 that restricts the direction of oil flow to only one direction from the upstream side to the downstream side, and the check valve 48 branches off. An oil pressure sensor 70 is disposed between the point 53c and detects the oil pressure in the oil supply passage 50 (upstream of the check valve 48 in the oil passage 69). The oil pressure sensor 70 detects the oil pressure in the oil pressure path (oil supply path 50) for supplying oil to the lubrication part of the engine 2 and the hydraulic actuator by the oil pump 36.

  The oil passage 69 branches at the branch point 69a downstream of the check valve 48 into the two oil passages 61 and 62 communicating with the mounting holes 26 and 27 for the HLA 25 with a valve stop mechanism. The oil passages 61 and 62 are connected to the valve stop mechanism of the HLA 25 with the valve stop mechanism on the intake side and the exhaust side via the second direction switching valves 46 and 47 on the intake side and the exhaust side, respectively. By controlling the direction switching valves 46 and 47, oil is supplied to each valve stop mechanism.

  The check valve 48 is energized by a spring so as to open when the hydraulic pressure in the third communication passage 53 exceeds the required hydraulic pressure of the valve stop mechanism of the HLA 25, and the oil flows only in one direction from the upstream side to the downstream side. To regulate. The check valve 48 opens with a hydraulic pressure larger than the required hydraulic pressure of the VVTs 32 and 33. If the VVTs 32 and 33 are operated during the reduced cylinder operation for operating the valve stop mechanism, the oil pressure in the third communication passage 53 (and the oil pressure detected by the oil pressure sensor 70) may decrease. Since the check valve 48 provided shields the flow of oil from the valve stop mechanism to the third communication passage 53 upstream of the check valve 48, the valve stop mechanism downstream of the check valve 48 is provided. The required oil pressure at is secured.

  The metal bearing for rotatably supporting the crankshaft 9 and the camshafts 18 and 19 and the lubricating and cooling oil supplied to the piston 8 and the camshafts 18 and 19 are shown after being cooled and lubricated. The oil is dropped into the oil pan 6 through the drain oil passage and is recirculated by the oil pump 36.

  The operation of the engine 2 is controlled by the controller 100. Detection information from various sensors that detect the operating state of the engine 2 is input to the controller 100. For example, the controller 100 detects the rotation angle of the crankshaft 9 by the crank angle sensor 71 and detects the engine rotation speed based on this detection signal. Further, the air flow sensor 72 detects the amount of air taken in by the engine 2 and detects the engine load based on this. Further, the oil temperature sensor 73 and the oil pressure sensor 70 detect the temperature and pressure of the oil in the oil pressure path, respectively. The oil temperature sensor 73 is disposed in the hydraulic path (in the present embodiment, the third communication path 53 of the oil supply path 50). Further, a cam angle sensor 74 provided in the vicinity of the camshafts 18 and 19 detects the rotational phase of the camshafts 18 and 19 and detects the operating angles of the VVTs 32 and 33 based on the cam angles. Further, the water temperature sensor 75 detects the temperature of cooling water that cools the engine 2 (hereinafter referred to as water temperature).

  The controller 100 is a control device based on a well-known microcomputer, and includes various sensors (hydraulic sensor 70, crank angle sensor 71, air flow sensor 72, oil temperature sensor 73, cam angle sensor 74, water temperature sensor 75, etc.). A signal input unit for inputting the detection signal, a calculation unit for performing calculation processing related to control, and devices to be controlled (first direction switching valves 34 and 35, second direction switching valves 46 and 47, linear solenoid valve 49). Etc.) and a storage unit for storing programs and data (such as a hydraulic control map and characteristic table described later) necessary for control.

  The linear solenoid valve 49 is a flow rate (discharge amount) control valve for controlling the discharge amount from the oil pump 36 in accordance with the operating state of the engine 2. The oil is supplied to the pressure chamber 369 of the oil pump 36 when the linear solenoid valve 49 is opened. However, the configuration of the linear solenoid valve 49 itself is well known, and a description thereof will be omitted.

  The controller 100 controls the hydraulic pressure supplied to the pressure chamber 369 of the oil pump 36 by supplying a duty ratio control signal to the linear solenoid valve 49 and adjusting the flow rate through the linear solenoid valve 49. The flow rate (discharge amount) of the oil pump 36 is controlled by controlling the amount of eccentricity of the cam ring 366 and the amount of change in the internal volume of the pump chamber 365 by the hydraulic pressure of the pressure chamber 369. That is, the capacity of the oil pump 36 is controlled by the duty ratio. Here, since the oil pump 36 is driven by the crankshaft 9 of the engine 2, the flow rate (discharge amount) of the oil pump 36 is proportional to the engine speed, as shown in FIG. When the duty ratio represents the ratio of the energization time to the linear solenoid valve 49 with respect to the time of one cycle, as shown in the figure, the hydraulic pressure to the pressure chamber 369 of the oil pump 36 increases as the duty ratio increases. The gradient of the flow rate of the oil pump 36 with respect to the rotation speed is reduced. As the discharge amount of the oil pump 36 increases, the driving load of the oil pump 36 driven by the engine 2 increases. The control of the discharge amount of the oil pump 36 is also the control of the driving load of the oil pump 36.

  As described above, the controller 100 configures a control unit that controls the discharge amount of the oil pump 36 by changing the capacity of the oil pump 36.

  In the hydraulic system 1, oil is supplied to a plurality of hydraulic actuators by a single oil pump 36, and the required hydraulic pressure required by each hydraulic actuator changes according to the operating state of the engine 2. Therefore, in order to obtain a hydraulic pressure that is required for all hydraulic operating devices in all operating states of the engine 2, the oil pump 36 has the highest required hydraulic pressure of each hydraulic operating device for each operating state of the engine 2. It is necessary to set a hydraulic pressure higher than the required hydraulic pressure to a target hydraulic pressure corresponding to the operating state of the engine 2. For this purpose, in this embodiment, the required hydraulic pressure of the valve stop mechanism, the oil jet 28, the journal of the crankshaft 9 and the VVTs 32 and 33 are relatively high among all hydraulic actuators. The target hydraulic pressure may be set as follows. This is because, if the target oil pressure is set in this way, other hydraulic actuators having a relatively low required oil pressure naturally satisfy the required oil pressure.

  In the present embodiment, for each operating state of the engine 2, a hydraulic target pressure in which a temporary target hydraulic pressure in the operating state is preset based on the highest required hydraulic pressure among the required hydraulic pressures of the VVTs 32 and 33, the metal bearings, and the oil jet 28. A control map is stored in the storage unit of the controller 100. The controller 100 reads the temporary target oil pressure corresponding to the operating state of the engine 2 from the oil pressure control map, and uses the higher one of the read temporary target oil pressure and the required oil pressure of the valve stop mechanism of the HLA 25 as the target oil pressure. Set to. Then, the controller 100 executes hydraulic feedback control for controlling the discharge amount of the oil pump 36 so that the hydraulic pressure (actual hydraulic pressure) detected by the hydraulic sensor 70 becomes the target hydraulic pressure.

  Next, the characteristics of the linear solenoid valve 49 will be described with reference to FIGS. The upper diagram in FIG. 4 exemplifies a flow rate characteristic line indicating a change in the flow rate of the linear solenoid valve 49 with respect to the duty ratio of the control signal supplied to the linear solenoid valve 49 by the controller 100. When the linear solenoid valve 49 has a duty ratio lower than the predetermined duty ratio D1, the flow rate of the passage hardly changes with respect to the change of the duty ratio, and the change of the duty ratio is near the predetermined duty ratio D1. On the other hand, it has a characteristic that the passing flow rate changes rapidly. Further, the linear solenoid valve 49 has such a characteristic that when the duty is higher than the predetermined duty ratio D2, the passing flow rate hardly changes with respect to the change of the duty ratio. As described above, the controller 100 changes the duty ratio of the control signal supplied to the linear solenoid valve 49 in order to execute the hydraulic feedback control. However, when the controllability is taken into consideration, the passage flow rate is changed with respect to the change of the duty ratio. It is advantageous to control the linear solenoid valve 49 within a predetermined duty range (D1 to D2) that changes gradually.

  Therefore, the controller 100 stores a characteristic table showing the flow characteristics of the linear solenoid valve 49 as shown in the upper diagram of FIG. 4 in the storage unit, and the duty cycle range (set based on the characteristic table) ( In the example of FIG. 4, in D1 to D2), a control signal is supplied to the linear solenoid valve 49, and hydraulic feedback control for controlling the discharge amount of the oil pump 36 is executed. As a result of supplying the control signal to the linear solenoid valve 49 within the duty cycle range, as shown in the lower diagram of FIG. 4, the oil pressure in the oil supply passage 50 changes (however, the engine speed is fixed).

  However, the flow characteristics of the linear solenoid valve 49 may differ depending on individual differences of the linear solenoid valve 49. For example, as illustrated by a one-dot chain line in FIG. As a result, the passing flow rate may be low. In addition, the broken line of FIG. 5 has illustrated the upper limit specification and the lower limit specification of the linear solenoid valve 49, respectively. Within this range, it is assumed that the flow characteristics of the linear solenoid valve 49 are different.

  Even if the controller 100 supplies a control signal to the linear solenoid valve 49 in the duty cycle range based on the characteristic table stored in advance, the passage flow rate of the linear solenoid valve 49 varies depending on individual differences of the linear solenoid valve 49. become. As a result, the controllability of the hydraulic feedback control is deteriorated. Specifically, when switching the supply and discharge of the hydraulic pressure to the valve stop mechanism for switching between the reduced cylinder operation and the all cylinder operation, or when the hydraulic pressure to the VVTs 32 and 33 is changed. The responsiveness when the target hydraulic pressure is changed is deteriorated along with the change in the operating state of the engine 2 such as when supplying and discharging.

  Therefore, the hydraulic system 1 is configured such that the controller 100 performs learning correction of the characteristic table of the linear solenoid valve 49. FIG. 6 shows a flowchart relating to learning correction of the characteristic table, which is executed by the controller 100. In this learning correction, a nominal characteristic table based on the upper limit standard and the lower limit standard of the linear solenoid valve 49 is stored in advance, and the detected value of the hydraulic sensor 70 and the target are set in a state where a predetermined learning execution condition is satisfied. The correction is performed by repeatedly correcting the characteristic table by a predetermined amount based on the deviation from the hydraulic pressure.

  The flow in FIG. 6 starts by turning on the ignition switch. In the first step S1, it is determined whether or not the learned value can be reflected. As will be described later, this learning value corresponds to a correction value for correcting the characteristic table by learning already performed. When the learning value can be reflected, the process proceeds to step S2, and when the learning value cannot be reflected, the process proceeds to step S3. Here, it is assumed that learning has not yet been performed and that the learning value cannot be reflected, and the process proceeds to step S3.

  In step S3, hydraulic feedback control is executed based on a nominal characteristic table stored in the controller 100. In a succeeding step S4, it is determined whether or not a learning execution condition is satisfied.

  The learning execution condition in step S4 includes whether or not the oil temperature is within a predetermined range. The oil temperature is detected by the oil temperature sensor 73 described above. When the oil temperature is too low or too high, the kinematic viscosity of the oil may be too high or too low, so that detection of the oil pressure by the oil pressure sensor 70 may become unstable, and learning accuracy will be reduced. . Therefore, one of the learning execution conditions is that the oil temperature is within a predetermined range so that the detection of the oil pressure by the oil pressure sensor 70 is stabilized.

  In addition, the learning execution condition of step S4 includes whether or not the duty ratio of the control signal supplied to the linear solenoid valve 49 is within a predetermined learning range. This learning range may be the same as the use duty range described above, or may be narrower toward the center than the use duty range. As described above, when the duty ratio is low (near D1) or when the duty ratio is high (near D2), the change in the flow rate of the linear solenoid valve 49 may greatly change with respect to the change in the duty ratio. For this reason, the learning accuracy decreases. Therefore, one of the learning execution conditions is that the duty ratio of the control signal within which the passing flow rate changes stably with respect to the change of the duty ratio is within a predetermined learning range.

  When the determination in step S4 is YES, the process proceeds to step S5, and when the determination is NO, the process proceeds to step S8.

  In step S5, based on the detection value of the hydraulic pressure sensor 70, it is determined whether or not a change in actual hydraulic pressure (deviation of the actual hydraulic pressure with respect to the target hydraulic pressure) has been detected. When a deviation is detected, the process proceeds from step S5 to step S6. When no deviation is detected, the process proceeds to step S8.

  In step S6, it is determined whether the characteristic table can be corrected based on the deviation detected in step S5. That is, for example, when the target hydraulic pressure is changed due to a change in the operating state of the engine 2, the change in the detection value of the hydraulic sensor 70 may become large, and as a result, a deviation in the actual hydraulic pressure is detected. May end up. In this case, if the characteristic table is corrected, the learning accuracy decreases. Therefore, an upper limit value and a lower limit value of the deviation may be set in advance, and when the detected deviation exceeds the upper limit value and the lower limit value, it may be determined that learning is impossible. The upper limit value and the lower limit value may be set based on the upper limit standard and the lower limit standard of the linear solenoid valve 49, for example. Further, the discharge amount of the oil pump 36 changes with engine rotation. When there is a large rotational change such that the rotational change of the engine 2 exceeds a predetermined value, the control operates so as to suppress the hydraulic pressure change, but after detecting the rotational change, the duty ratio is controlled to control the linear solenoid valve 49. Since this control is a follow-up control that suppresses the change in hydraulic pressure by adjusting the flow rate, there is a case where the hydraulic pressure is inevitably changed due to a sudden change in engine rotation due to acceleration or shift change that greatly depresses the accelerator. In this case, the learning accuracy is reduced. Therefore, it may be determined that learning is not possible when the engine rotation change is greater than or equal to a predetermined value. That is, when it is considered that the deviation due to the individual difference of the linear solenoid valve 49 is exceeded or a factor other than the individual difference is included, the learning correction of the characteristic table may not be performed. When the determination in step S6 is YES, the process proceeds to step S7. On the other hand, when the determination in step S6 is NO, the process proceeds to step S8.

  In step S7, the characteristic table is corrected. Specifically, the current characteristic table is offset by a predetermined offset amount based on the direction of deviation, such as whether the actual hydraulic pressure is higher or lower than the target hydraulic pressure detected in step S5 (arrow in FIG. 5). reference). In step S8, which will be described later, steps S1 to S7 are repeated until the engine is stopped. Therefore, if the current characteristic table is a nominal characteristic table, the nominal characteristic table is offset, and the characteristic already exists. If the table is corrected, in step S7, the corrected characteristic table is further offset. In this way, learning correction is performed so that the characteristic table of the linear solenoid valve 49 approaches the actual characteristics.

  In step S8, it is determined whether or not the ignition switch is turned off. If the ignition switch is turned on, the process returns to step S1. As described above, steps S1 to S7 are repeated. As a result, offset correction of the characteristic table may be repeated, but it is preferable to set a limit value for offset correction in advance. This limit value may be set based on the upper limit standard and the lower limit standard of the linear solenoid valve 49 described above, for example.

  On the other hand, if the ignition switch is turned off in step S8, the process proceeds to step S9. In step S9, the learning value is backed up and the flow ends. Next time when the ignition switch is turned on and this flow starts, the determination in step S1 is YES, and hydraulic feedback control is executed based on the characteristic table corrected by the learning value backed up in step S9 ( Step S2).

  As described above, in the hydraulic system 1, the oil discharge amount of the variable displacement oil pump 36 is controlled using the linear solenoid valve 49 having the characteristics shown in the upper diagram of FIG. 4 with respect to the duty ratio. Thus, when controlling the oil pressure of the oil supply passage 50, the actual characteristics of the linear solenoid valve 49 and the control of the linear solenoid valve 49 are used based on the pressure change of the oil supply passage 50 detected by the oil pressure sensor 70. It is determined whether or not the characteristic table (upper figure in FIG. 4) is different, and if so, learning correction is performed to offset the characteristic table of the linear solenoid valve 49, thereby The difference between the actual characteristic and the characteristic table used for the control of the linear solenoid valve 49 is reduced or eliminated.

  Further, when a preset condition for executing learning correction is satisfied, if the hydraulic pressure detected by the hydraulic pressure sensor 70 deviates from the target hydraulic pressure, the learning correction is performed to perform accurate learning control. Is possible.

  That is, by performing learning correction when the oil temperature is within a predetermined range, learning correction is avoided when the change in oil pressure detected by the oil pressure sensor 70 becomes unstable due to the kinematic viscosity of the oil. It is possible to prevent the accuracy of the deterioration.

  In addition, by performing learning correction when the duty ratio of the control signal supplied to the linear solenoid valve 49 is within a predetermined learning range, learning is performed in a state in which the passing flow rate changes in a predetermined manner with respect to the change in the duty ratio. Correction is performed, and the accuracy of learning correction can be increased.

  Further, when the deviation of the hydraulic pressure detected by the hydraulic sensor 70 exceeds a preset upper limit value and lower limit value, the hydraulic correction devices such as the HLA 25 with a valve stop mechanism and the VVTs 32 and 33 are operated by prohibiting learning correction. In some cases, the accuracy of learning correction is increased by not performing learning correction.

  In this way, by learning and correcting the characteristic table of the linear solenoid valve 49, the linear solenoid valve 49 can be controlled based on actual characteristics or characteristics close to actual characteristics. Controllability of feedback control, that is, control responsiveness can be improved, and high responsiveness required for the hydraulic system 1 can be satisfied.

  In the above configuration, the example in which the HLA 25 is provided with the valve stop mechanism for switching between the reduced cylinder operation and the all cylinder operation is shown, but the valve stop mechanism is not limited to this configuration. For example, the opening and closing of the intake valve and / or the exhaust valve itself is performed by a hydraulically driven variable valve opening / closing mechanism configured to be performed via hydraulic pressure, and a valve stop mechanism is provided in the hydraulically driven variable valve opening / closing mechanism. May be.

  The engine 2 is not limited to an inline 4-cylinder gasoline engine, and may be any engine. For example, a diesel engine may be used.

14 Intake valve 15 Exhaust valve 100 Controller (control unit)
2 Engine 25 HLA with valve stop mechanism (hydraulic actuator, valve stop device)
32 VVT (hydraulic actuator)
33 VVT (hydraulic actuator)
36 Oil pump 369 Pressure chamber 49 Linear solenoid valve 50 Oil supply path (hydraulic path)
70 Hydraulic sensor

Claims (7)

An oil pump with variable capacity,
A hydraulic actuator connected to the oil pump via a hydraulic path;
A hydraulic sensor configured to detect the hydraulic pressure of the hydraulic path;
A control unit configured to control the oil pump while changing the capacity of the oil pump so that the hydraulic pressure of the hydraulic path becomes a target hydraulic pressure,
The control unit includes a linear solenoid valve that controls a hydraulic pressure supplied to the pressure chamber of the oil pump, and changes a duty ratio of a control signal supplied to the linear solenoid valve to thereby change the pressure chamber of the oil pump. The hydraulic pressure to be supplied is changed, and the capacity of the oil pump is changed,
The linear solenoid valve has a predetermined change in passing flow rate with respect to a change in duty ratio in a predetermined use duty range, while the duty ratio is lower than the use duty range and lower than the use duty range. When the duty ratio is high, it has a characteristic that the passage flow rate does not change with respect to the change of the duty ratio,
The controller is also configured to supply a control signal to the linear solenoid valve in the duty cycle range based on a table indicating the characteristics of the linear solenoid valve.
The control unit further comprises a control device for a variable displacement oil pump configured to perform learning correction for offsetting a characteristic table of the linear solenoid valve based on a change in pressure of the hydraulic path detected by the hydraulic sensor. In the control apparatus of the variable displacement oil pump according to claim 1,
The control unit is a control device for a variable displacement oil pump that performs the learning correction when a hydraulic pressure detected by the hydraulic pressure sensor is deviated from a target hydraulic pressure when a condition for executing the learning correction is satisfied. In the control apparatus of the variable displacement oil pump according to claim 2,
The control unit is a control device of a variable displacement oil pump that performs the learning correction when the oil temperature is in a predetermined range. In the control apparatus of the variable displacement type oil pump according to claim 2 or 3,
The control unit is a control device for a variable displacement oil pump that performs the learning correction when a duty ratio of a control signal supplied to the linear solenoid valve is within a predetermined learning range. In the control apparatus of the variable displacement type oil pump according to any one of claims 2 to 4,
The control unit is a control device for a variable displacement oil pump that prohibits the learning correction when a deviation in hydraulic pressure detected by the hydraulic sensor exceeds a preset upper limit value and lower limit value. In the control apparatus of the variable displacement type oil pump according to any one of claims 2 to 5,
The oil pump is driven by an engine mounted on an automobile,
The control unit is a control device for a variable displacement oil pump that prohibits the learning correction when a change in rotation of the engine is equal to or greater than a predetermined value. In the control apparatus of the variable displacement oil pump according to any one of claims 1 to 6,
The oil pump is driven by an engine mounted on an automobile,
The hydraulic actuator includes a variable capacity including a valve stop device configured to stop the operation of at least one of an intake valve and an exhaust valve so as to stop a part of a plurality of cylinders of the engine. Type oil pump control device.

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