JP6493438B2 - Hydraulic control device for engine - Google Patents

Description

  The technology disclosed herein relates to an engine hydraulic control device.

  For example, Patent Document 1 discloses a valve stop mechanism that operates by receiving hydraulic pressure to switch the engine from full cylinder operation to reduced cylinder operation. Further, Patent Document 1 also discloses that the oil discharge amount of the variable displacement oil pump is adjusted so that the hydraulic pressure supplied to the valve stop mechanism becomes a predetermined target hydraulic pressure. Thus, by performing feedback control via the oil discharge amount, it is possible to adjust to the minimum required hydraulic pressure.

JP 2014-199011 A

  As described above, the switching to the reduced cylinder operation is realized by the operation of the valve stop mechanism. In order to operate it, the hydraulic pressure (maintenance hydraulic pressure) normally required for maintaining the reduced cylinder operation is required. It is known that high oil pressure (transient oil pressure) is required.

  However, in order to ensure such a transient oil pressure, when feedback control as in Patent Document 1 is performed, the operation of the valve stop mechanism may be delayed depending on the oil temperature of the oil supplied to the valve stop mechanism. In particular, the inventors of the present application have noticed.

  In other words, for example, when the oil temperature is high, the amount of leakage from the sliding portion or the like increases due to the lower viscosity of the oil, making it difficult to increase the hydraulic pressure. In this case, since the feedback control is repeatedly performed, it takes a long time to reach the transient hydraulic pressure. Considering that the transient hydraulic pressure is relatively high, it is difficult to operate the valve stop mechanism with good response.

  On the other hand, when the oil temperature is low, the amount of leakage is reduced, but the flow resistance increases as the oil viscosity increases.Therefore, depending on the length of the path connecting the oil pump and the valve stop mechanism, Start-up is delayed (hydraulic responsiveness deteriorates). In this case, as in the case where the oil temperature is high, it is difficult to operate the valve stop mechanism with good response.

  Thus, if there is a delay in the operation of the valve stop mechanism, it is inconvenient to quickly switch from full cylinder operation to reduced cylinder operation. This is not preferable for reducing the fuel consumption of the engine.

  The technology disclosed herein has been made in view of such a point, and an object of the technology is to operate a valve stop mechanism in a responsive manner in an engine hydraulic control device, thereby reducing engine fuel consumption. It is in.

  The technology disclosed herein switches between an all-cylinder operation having a plurality of cylinders and operating all of the plurality of cylinders, and a reduced cylinder operation in which some of the plurality of cylinders are deactivated. A hydraulic control device for an engine configured as described above, wherein a valve stop mechanism for switching the engine from the full-cylinder operation to the reduced-cylinder operation by receiving pressurized oil and operating the oil to the valve stop mechanism An oil pump that supplies oil, an oil control valve that adjusts an oil discharge amount of the oil pump, and is connected to the oil control valve and outputs a control signal to the oil control valve, and via the control signal By controlling the hydraulic pressure of oil supplied to the valve stop mechanism, a controller for operating the valve stop mechanism, and a controller connected to the controller and supplied to the valve stop mechanism. Detecting the oil pressure of the oil to be performed, outputting a signal indicating the detection result to the controller, detecting the oil temperature of the oil connected to the controller and supplied to the valve stop mechanism, An oil temperature sensor that outputs a signal indicating the detection result to the controller.

  When the controller operates the valve stop mechanism and the oil temperature detected by the oil temperature sensor is within a predetermined range, the oil pressure detected by the oil pressure sensor is based on the operating state of the engine. While performing feedback control to output a control signal to the oil control valve so that the set target oil pressure is reached, when the oil temperature detected by the oil temperature sensor is outside the predetermined range, the feedback control Instead, maximum discharge control for outputting a control signal to the oil control valve is performed so that the oil discharge amount is set to the maximum amount.

  In other words, this hydraulic control device is provided with a valve stop mechanism that operates in response to oil pressure, and by operating this valve stop mechanism, the engine may be switched from full cylinder operation to reduced cylinder operation. In that case, since it is required to supply pressurized oil to the valve stop mechanism, it is required to increase the hydraulic pressure supplied to the valve stop mechanism, for example, by increasing the oil discharge amount.

  In order to increase the hydraulic pressure, it is conceivable to execute the feedback control as described above. However, depending on the oil temperature, the hydraulic pressure supplied to the valve stop mechanism becomes difficult to rise or the rise of the hydraulic pressure is delayed. As a result, it may be difficult to operate the valve stop mechanism with good response.

  On the other hand, in this hydraulic control device, maximum discharge control is executed instead of feedback control in accordance with the oil temperature of the oil. When maximum discharge control is performed, the oil discharge amount of the oil pump is set to the maximum amount regardless of the target hydraulic pressure of the valve stop mechanism. The hydraulic pressure can be increased as quickly as possible by the amount of oil discharge increased. Therefore, it is possible to operate the valve stop mechanism with good response, and to speed up the switching from the full cylinder operation to the reduced cylinder operation. As a result, the fuel consumption of the engine can be reduced.

  Further, when the maximum discharge control is performed regardless of the oil temperature, for example, when the oil pressure is relatively likely to rise, the oil pressure may be increased more than necessary. In that case, there is a possibility that the drive loss of the oil pump increases or the oil jet is activated by excessive hydraulic pressure. Such a situation is undesirable for reducing fuel consumption.

  On the other hand, in this hydraulic control device, feedback control and maximum discharge control are selectively used based on the oil temperature. For example, when the oil temperature is relatively easy to increase, feedback control suitable for obtaining the minimum required oil pressure is performed, while when the oil temperature is relatively difficult to increase, instead of such feedback control, By performing maximum discharge control suitable for quickly increasing the hydraulic pressure, both the response performance of the valve stop mechanism and the fuel efficiency performance of the engine can be achieved.

  In addition, when operating the valve stop mechanism, the controller performs the feedback control when the oil temperature detected by the oil temperature sensor exceeds a predetermined first threshold value, and on the other hand, when the oil temperature is equal to or lower than the first threshold value, It may be configured to perform discharge control.

  When the oil temperature is lowered, the flow resistance in the hydraulic path is increased by the increase in the viscosity of the oil, and the oil becomes difficult to flow. Therefore, the rise of the hydraulic pressure is delayed according to the length of the path connecting the oil pump and the valve stop mechanism. In this case, it may be difficult to operate the valve stop mechanism with good response.

  On the other hand, in this hydraulic control device, maximum discharge control is performed when the oil temperature is equal to or lower than the first threshold value. As a result, the hydraulic pressure can be increased as quickly as possible, and the valve stop mechanism can be operated with good response. This is advantageous in reducing the fuel consumption of the engine.

  Moreover, since oil viscosity will become low if oil temperature becomes high to some extent, oil becomes easy to flow relatively. As a result, the delay in the rise is eliminated, and the valve stop mechanism may be able to be operated with good response without performing the maximum discharge control.

  Therefore, in this hydraulic control device, when the oil temperature exceeds the first threshold value, feedback control is performed instead of the maximum discharge control. This is advantageous in suppressing an excessive increase in hydraulic pressure and, in turn, reducing fuel consumption of the engine.

  In addition, when operating the valve stop mechanism, the controller performs the maximum discharge control when the oil temperature detected by the oil temperature sensor is equal to or higher than a second threshold set higher than the first threshold. It may be configured.

  As described above, when the oil temperature exceeds the first threshold value, feedback control is performed. When the oil temperature becomes sufficiently higher than the first threshold value, the oil viscosity decreases, so that oil leaks at the sliding portion of the engine. The amount will increase. If the amount of leak increases, the hydraulic pressure is less likely to increase. Therefore, if the feedback control is performed, it may be difficult to operate the valve stop mechanism with good response.

  On the other hand, in this hydraulic control device, when the oil temperature is equal to or higher than the second threshold value, maximum discharge control is performed instead of feedback control. As a result, the hydraulic pressure can be increased as quickly as possible, and the valve stop mechanism can be operated with good response. This is effective in suppressing the fuel consumption of the engine.

  The controller may set the second threshold value higher when the rotational speed of the engine is higher than when the rotational speed is low.

  When the rotational speed of the engine increases, the flow rate of oil discharged from the oil pump per unit time (pump discharge amount) also increases, so the influence of leakage is reduced. Therefore, when the rotational speed is high, the hydraulic pressure is more likely to increase than when the rotational speed is lower. In this case, the maximum discharge control may cause an increase in fuel consumption due to a drive loss of the pump or the like.

  According to the above configuration, the operating range in which feedback control is performed is expanded by setting the second threshold value higher as the engine speed increases. By doing so, it becomes advantageous in suppressing the fuel consumption of the engine.

  As described above, according to the hydraulic control apparatus for an engine, the valve stop mechanism can be operated with good response, and the fuel consumption of the engine can be reduced.

FIG. 1 is a cross-sectional view illustrating the configuration of an engine. 2A and 2B are diagrams for explaining the configuration and operation of the valve stop mechanism, where FIG. 2A shows the locked state, FIG. 2B shows the unlocked state, and FIG. 2C shows the state where the valve operation is stopped. . FIG. 3 is a cross-sectional view illustrating the configuration of the variable valve timing mechanism. FIG. 4 is a system diagram illustrating the configuration of the hydraulic control device. FIG. 5 is a map of the base oil pressure. FIG. 6 is a map of required oil pressure at the time of request for lubrication improvement. FIG. 7 is a map of the required oil pressure of the oil jet. FIG. 8 is a map of the required oil pressure of the exhaust side VVT. FIG. 9 is a block diagram of hydraulic feedback control. FIG. 10 is a diagram illustrating characteristics of the oil pump. FIG. 11 is a diagram showing a reduced cylinder operation region. FIG. 12 is a map showing the maintenance hydraulic pressure and the transient hydraulic pressure of the valve stop mechanism. FIG. 13 is a diagram showing the reduced cylinder operation region divided into an operation region in which feedback control is performed and an operation region in which maximum discharge control is performed. FIG. 14 is a time chart showing the change in hydraulic pressure over time. FIG. 15 is a flowchart illustrating processing relating to branching between feedback control and maximum discharge control and processing relating to feedback control in hydraulic control. FIG. 16 is a flowchart of processing related to maximum discharge control in hydraulic control.

  Hereinafter, exemplary embodiments will be described in detail with reference to the drawings.

<Engine>
FIG. 1 is a schematic sectional view of the engine 100. This engine 100 is an in-line four-cylinder engine mounted on an automobile. That is, in the engine 100, four cylinders are arranged in series in the cylinder row direction (direction perpendicular to the paper surface in FIG. 1). Hereinafter, the four cylinders may be referred to as “first cylinder”, “second cylinder”, “third cylinder”, and “fourth cylinder” in order from the end in the cylinder row direction. In order to reduce fuel consumption, the engine 100 is operated in an operation for operating all of these cylinders (all cylinder operation) and an operation for stopping some cylinders such as half of the cylinders (reduction in cylinder operation). It is comprised so that it may switch according to the driving | running state of 100.

  The engine 100 includes a cylinder head 1, a cylinder block 2 attached to the lower side of the cylinder head 1, and an oil pan 3 attached to the lower side of the cylinder block 2. The cylinder block 2 has an upper block 21 and a lower block 22. The lower block 22 is attached to the lower surface of the upper block 21, and the oil pan 3 is attached to the lower surface of the lower block 22.

  The upper block 21 is formed with four cylindrical cylinder bores 23 constituting each cylinder so as to extend in the vertical direction (only one cylinder bore 23 is shown in FIG. 1). The cylinder head 1 is assembled on the upper block 21 so as to close the upper openings of the cylinder bores 23. A piston 24 is installed inside the cylinder bore 23 so as to be slidable in the vertical direction. The piston 24 is connected to a crankshaft 26 positioned below via a connecting rod 25. Inside the engine 100, a combustion chamber 27 is defined by an inner peripheral wall of the cylinder bore 23, an upper surface of the piston 24, and a lower wall of the cylinder head 1 facing the cylinder bore 23.

  The cylinder head 1 is provided with an intake port 11 and an exhaust port 12 having an opening at the top of the combustion chamber 27. The intake port 11 is provided with an intake valve 13 that opens and closes the opening of the intake port 11, and the exhaust port 12 is provided with an exhaust valve 14 that opens and closes the opening of the exhaust port 12. Each of the intake valve 13 and the exhaust valve 14 is driven by an intake cam portion 41 a provided on the intake cam shaft 41 and an exhaust cam portion 42 a provided on the exhaust cam shaft 42.

  Specifically, the intake valve 13 and the exhaust valve 14 are urged by valve springs 15 and 16 in a direction to close the opening (upward in FIG. 1). Between the intake valve 13 and the intake cam portion 41a, and between the exhaust valve 14 and the exhaust cam portion 42a, an intake swing arm 43 and an exhaust swing arm 44 having cam followers 43a and 44a, respectively, in the substantially central portion are provided. Has been.

  One end portions of the intake swing arm 43 and the exhaust swing arm 44 are supported by hydraulic lash adjusters (HLA) 45 and 46, respectively. When the cam followers 43a, 44a are pushed by the intake cam portion 41a or the exhaust cam portion 42a, the intake swing arm 43 or the exhaust swing arm 44 swings with one end portion supported by the HLA 45, 46 as a fulcrum. Each of the other ends of the swinging intake swing arm 43 or the exhaust swing arm 44 thus swinging pushes down the intake valve 13 or the exhaust valve 14 against the urging force of the valve springs 15, 16. The valve 14 moves in the direction of opening the opening (downward in FIG. 1). The HLA 45 and 46 are automatically adjusted so that the valve clearance becomes zero by hydraulic pressure.

  The HLA 45 and 46 provided in the first cylinder and the fourth cylinder are provided with valve stop mechanisms 45d and 46d for stopping the operations of the intake valve 13 and the exhaust valve 14, respectively (details will be described later). On the other hand, the valve stop mechanisms 45d and 46d are not provided in the HLA 45 and 46 provided in the second cylinder and the third cylinder. Hereinafter, the former may be referred to as high-performance HLA 45a and 46a, and the latter may be referred to as standard HLA 45b and 46b.

  Switching between all-cylinder operation and reduced-cylinder operation is performed by operation of high-function HLA 45a and 46a (details will be described later). That is, oil pressurized to a predetermined transient oil pressure is supplied via an oil supply path (formed in the cylinder head 1) communicating with the high function HLA 45a and 46a, whereby the high function HLA 45a and 46a are hydraulically controlled. Switching from full cylinder operation to reduced cylinder operation is performed.

<Valve stop mechanism>
FIG. 2A to FIG. 2C show a high function HLA 45a. The structure of the high-function HLA 45a is substantially the same as the standard HLA 45b and 46b except for the presence or absence of the valve stop mechanism 45d. Therefore, the high-function HLA 45a will be described below as an example.

  The high function HLA 45a has a pivot mechanism 45c and a valve stop mechanism 45d. The pivot mechanism 45c is a known HLA pivot mechanism, and is configured to automatically adjust the valve clearance to zero by hydraulic pressure. The valve stop mechanism 45d is a mechanism that switches between operation and stop of the corresponding intake valve 13 or exhaust valve 14.

  As shown in FIG. 2A, the valve stop mechanism 45d includes a bottomed cylindrical outer cylinder 45e that accommodates the pivot mechanism 45c in a state in which it can slide and protrude in the axial direction, and a side peripheral surface of the outer cylinder 45e. A pair of lock pins 45g inserted in two through holes 45f formed opposite to each other so as to be able to advance and retreat, a lock spring 45h for urging each lock pin 45g radially outward of the outer cylinder 45e, and an outer cylinder 45e And a lost motion spring 45i that is urged in a direction to project the pivot mechanism 45c.

  The lock pin 45g is disposed at the lower end of the pivot mechanism 45c. The lock pin 45g is operated by hydraulic pressure to switch the valve stop mechanism 45d between a locked state where the pivot mechanism 45c is fixed so as not to be displaced and an unlocked state where the pivot mechanism 45c is slidable in the axial direction.

  FIG. 2A shows the locked state. In the locked state, the pivot mechanism 45c protrudes from the outer cylinder 45e with a relatively large protruding amount, and the movement of the outer cylinder 45e in the axial direction is restricted by fitting the lock pin 45g into the through hole 45f. Yes. In this locked state, the top of the pivot mechanism 45c is in contact with one end of the intake swing arm 43 or the exhaust swing arm 44, and functions as a fulcrum of the swing.

  That is, when the valve stop mechanism 45d is in the locked state, the high function HLA 45a is substantially the same as the standard HLA 45b, 46b, and the corresponding intake valve 13 or exhaust valve 14 operates normally.

  On the other hand, when a predetermined oil pressure is applied to the lock pin 45g by supplying pressurized oil to the high function HLA 45a as indicated by a black arrow in FIG. 2B, the lock pin 45g It moves to the inner side in the radial direction against the urging force, and the fitting with the through hole 45f is released. As a result, the lock pin 45g is switched to the unlocked state in which it is retracted into the outer cylinder 45e until it does not fit into the through hole 45f.

  Since the pivot mechanism 45c is biased by the lost motion spring 45i, the pivot mechanism 45c protrudes from the outer cylinder 45e with a relatively large projecting amount. However, the biasing force of the lost motion spring 45i is the valve springs 15, 16 Is set smaller than the urging force for urging the intake valve 13 and the exhaust valve 14 in the closing direction. Therefore, in the unlocked state, when the cam followers 43a and 44a are respectively pushed by the intake cam portion 41a or the exhaust cam portion 42a, the intake swing arm 43 or the exhaust swing arm 44 supports the top of the intake valve 13 or the exhaust valve 14. The pivot mechanism 45c is displaced to the outside of the outer cylinder 45e against the urging force of the lost motion spring 45i as indicated by the white arrow in FIG.

  That is, when the valve stop mechanism 45d is in the unlocked state, the high function HLA 45a does not function as an HLA, and the corresponding intake valve 13 or exhaust valve 14 stops its operation. As a result, the cylinders provided with the intake valve 13 and the exhaust valve 14 cannot be operated and are in a cylinder deactivation state, and the above-described reduced cylinder operation is performed. During the reduced cylinder operation, the valve stop mechanism 45d is maintained in the unlocked state.

  A cam cap 47 is attached to the upper part of the cylinder head 1. By the cylinder head 1 and the cam cap 47, each of the intake cam shaft 41 and the exhaust cam shaft 42 is rotatably supported.

  An intake side oil shower 48 is provided above the intake cam shaft 41, while an exhaust side oil shower 49 is provided above the exhaust cam shaft 42. In the intake side oil shower 48 and the exhaust side oil shower 49, the oil is dripped at portions where the intake cam portion 41 a and the exhaust cam portion 42 a come into contact with the cam followers 43 a and 44 a of the intake swing arm 43 and the exhaust swing arm 44.

<Variable valve timing mechanism (VVT)>
The engine 100 is provided with a variable valve timing mechanism (hereinafter referred to as “VVT”) that changes the valve characteristics of the intake valve 13 and the exhaust valve 14. In the case of the engine 100, the intake side VVT 17 is electrically driven, and the exhaust side VVT 18 is hydraulically driven.

  FIG. 3 shows the exhaust side VVT 18. The exhaust side VVT 18 includes a substantially annular housing 18a and a rotor 18b accommodated inside the housing 18a. The housing 18a is integrated with a cam pulley 18c that rotates in conjunction with the crankshaft 26. The rotor 18b is integrated with an exhaust camshaft 42 that opens and closes the exhaust valve 14.

  On the outer periphery of the rotor 18b, a plurality of vane bodies 18d projecting radially are formed. A plurality of spaces for accommodating the vane bodies 18d are formed inside the housing 18a, and these spaces are partitioned by the vane bodies 18d, whereby the retarding working chamber 18e and the advance working chamber 18f are formed in the housing 18a. Are formed inside.

  Pressurized oil is supplied to each of the retard working chamber 18e and the advance working chamber 18f in order to change the opening / closing timing of the exhaust valve 14. As a result, when the hydraulic pressure in the retarded working chamber 18e becomes higher than the hydraulic pressure in the advanced working chamber 18f, the rotor 18b rotates in the opposite direction to the rotational direction of the housing 18a. That is, the exhaust camshaft 42 rotates in the opposite direction with respect to the cam pulley 18c, and the phase angle of the exhaust camshaft 42 with respect to the crankshaft changes in the retarded direction. As a result, the opening timing of the exhaust valve 14 is delayed.

  On the other hand, when the hydraulic pressure in the advance working chamber 18f becomes higher than the hydraulic pressure in the retard working chamber 18e, the rotor 18b rotates in the same direction with respect to the rotation direction of the housing 18a. That is, the exhaust cam shaft 42 rotates in the same direction with respect to the cam pulley 18c, and the phase angle of the exhaust cam shaft 42 with respect to the crankshaft changes in the advance direction. As a result, the opening timing of the exhaust valve 14 is advanced.

  Thus, the valve opening period of the intake valve 13 and the valve opening period of the exhaust valve 14 overlap by changing the valve opening timing of the exhaust valve 14 or the intake valve 13 by the exhaust side VVT 18 or the intake side VVT 17. The amount can be increased or decreased, and the fuel efficiency can be improved by increasing the internal EGR amount or reducing the pumping loss. The control for changing the valve opening timing by the exhaust side VVT 18 and the intake side VVT 17 is executed in both the all cylinder operation and the reduced cylinder operation.

<Hydraulic control system>
FIG. 4 shows a system diagram of the hydraulic control device of engine 100.

  The hydraulic control device supplies oil at a predetermined hydraulic pressure to a lubrication site of the engine 100 such as a hydraulic actuator (equipment operated by hydraulic pressure) attached to the engine 100 such as the HLA 45, 46 and the exhaust side VVT 18 or a bearing portion. It is a supply system. The hydraulic control device includes these hydraulic actuators, an oil pump 81, a hydraulic path, various sensors, a controller 60, and the like.

(Oil pump)
The oil pump 81 is a so-called variable displacement oil pump, and the flow rate (oil discharge amount) of oil discharged from the oil pump 81 per unit time can be adjusted by changing the capacity. The oil pump 81 is attached to the lower surface of the lower block 22 and is driven by the crankshaft 26. The oil pump 81 supplies oil to each hydraulic actuator via a hydraulic path when driven.

  Specifically, the oil pump 81 accommodates a drive shaft 81a, a rotor 81b connected to the drive shaft 81a, a plurality of vanes 81c provided so as to advance and retreat in the radial direction from the rotor 81b, and the rotor 81b and the vanes 81c. A cam ring 81d configured to adjust the amount of eccentricity with respect to the rotation center of the rotor 81b, a spring 81e for urging the cam ring 81d in a direction in which the amount of eccentricity with respect to the rotation center of the rotor 81b increases, and inside the rotor 81b. The ring member 81f is disposed, and the housing 81g accommodates the rotor 81b, the vane 81c, the cam ring 81d, the spring 81e, and the ring member 81f.

  Although illustration is omitted, one end of the drive shaft 81a protrudes outward of the housing 81g. A driven sprocket is connected to the one end, and a timing chain wound around the drive sprocket of the crankshaft 26 is wound around the driven sprocket. Thereby, the rotor 81b is rotationally driven by the crankshaft 26.

  When the rotor 81b rotates, each vane 81c slides on the inner peripheral surface of the cam ring 81d. As a result, a plurality of (seven in the example shown in FIG. 4) pump chambers 81i defined by the rotor 81b, the two adjacent vanes 81c, the cam ring 81d, and the housing 81g move in the sliding direction of the vanes 81c. .

  The housing 81g is formed with a suction port 81j for sucking oil into the pump chamber 81i and a discharge port 81k for discharging oil from the pump chamber 81i. An oil strainer 81l (immersed in oil stored in the oil pan 3) is connected to the suction port 81j. When the rotor 81b is driven to rotate, the oil stored in the oil pan 3 passes through the oil strainer 81l. The air is sucked from the suction port 81j into the pump chamber 81i (specifically, one pump chamber 81i located on the side closer to the suction port 81j among the plurality of pump chambers 81i). On the other hand, a hydraulic path is connected to the discharge port 81k, and the oil sucked from the suction port 81j is discharged from the discharge port 81k when the pump chamber 81i that sucked the oil moves to the side close to the discharge port 81k. Discharged into the hydraulic path.

  The cam ring 81d is supported by the housing 81g so as to swing around a predetermined fulcrum. The spring 81e biases the cam ring 81d in one of the swing directions. A pressure chamber 81m to which oil is supplied is defined between the cam ring 81d and the housing 81g, and the oil pressure of the oil in the pressure chamber 81m acts on the cam ring 81d. This hydraulic pressure biases the cam ring 81d to the other side in the swinging direction. Therefore, the cam ring 81d swings according to the balance between the biasing force of the spring 81e and the hydraulic pressure of the pressure chamber 81m, and the amount of eccentricity of the cam ring 81d with respect to the rotation center of the rotor 81b is determined. In accordance with the amount of eccentricity of the cam ring 81d, the capacity of the oil pump 81 changes and the oil discharge amount changes. Although illustration is omitted, for example, when oil is discharged from the pressure chamber 81m and the cam ring 81d is decentered to one end in the swinging direction, the pump chamber 81i located on the side close to the suction port 81j is discharged. The capacity of the pump chamber 81i located on the side close to the outlet 81k is the smallest. In this case, the oil discharge pressure is minimized, and as a result, the oil discharge amount is also minimized. On the other hand, when a sufficient amount of oil is supplied to the pressure chamber 81m and the cam ring 81d is decentered to the other end in the swinging direction, the discharge port with respect to the capacity of the pump chamber 81i located on the side close to the suction port 81j. The capacity of the pump chamber 81i located on the side close to 81k is the largest. In this case, the oil discharge pressure is maximized, and the oil discharge amount is also maximized.

(Hydraulic path)
The hydraulic path is formed by a hydraulic pipe or a flow path drilled in the cylinder block 2 or the like. Specifically, the hydraulic path is a main gallery 50 (see also FIG. 1) that extends in the cylinder row direction in the cylinder block 2, a control pressure path 54 that branches from the main gallery 50, and an oil pump 81 that connects the main gallery 50. From the first communication path 51, the second communication path 52 extending from the main gallery 50 to the cylinder head 1, the third communication path 53 extending in the substantially horizontal direction between the intake side and the exhaust side in the cylinder head 1, and the third communication path 53 It is comprised by the 1st-5th oil supply path 55-59 etc. which branch.

  The first communication path 51 is connected to the discharge port 81k of the oil pump 81 and an intermediate portion of the main gallery 50. In the first communication passage 51, an oil filter 82 and an oil cooler 83 are provided in order from the oil pump 81 side. Thereby, the oil discharged from the oil pump 81 to the first communication passage 51 is filtered by the oil filter 82. The filtered oil flows into the intermediate part of the main gallery 50 after the oil temperature is adjusted by the oil cooler 83.

  An oil jet 71 that injects oil to the back side of the four pistons 24 is connected to the main gallery 50 at intervals in the cylinder row direction (see also FIG. 1). The oil jet 71 has a check valve and a nozzle, and when a hydraulic pressure exceeding a predetermined value is applied, the check valve is opened to inject oil from the nozzle. The cooling of each piston 24 can be promoted by the oil jetted from the oil jet 71.

  Further, branch paths for supplying oil to the five bearing portions 29 that support the crankshaft 26 and the bearing portions 72 of the four connecting rods 25 are also connected to the main gallery 50 at intervals in the cylinder row direction. ing. One end side of the main gallery 50 is a terminal end connected to one branch path, and the other end side of the main gallery 50 is connected to a control pressure path 54, a second communication path 52, and a hydraulic chain tensioner (not shown). A branch path having an oil supply part 73 for supplying oil and an oil jet 74 for injecting oil to the timing chain is connected.

  Oil is always supplied to the main gallery 50. On the other end side of the main gallery 50, a hydraulic pressure sensor 50a that detects the oil pressure of the oil in the main gallery 50 is installed. Based on the detected value of the hydraulic sensor 50a, the hydraulic pressure of the hydraulic path is controlled (details will be described later).

  The control pressure path 54 is connected to the pressure chamber 81 m of the oil pump 81. The control pressure path 54 is provided with an oil supply unit 73, an oil filter 54a, and an oil control valve (discharge amount adjusting device) 84. The oil filtered through the oil pressure filter 54 a through the control pressure path 54 is adjusted by the oil control valve 84 and then flows into the pressure chamber 81 m of the oil pump 81. The oil control valve 84 adjusts the pressure in the pressure chamber 81m, and thus the eccentric amount of the cam ring 81d. As described above, when the eccentric amount of the cam ring 81d is adjusted, the oil discharge amount of the oil pump 81 increases or decreases. That is, the oil control valve 84 is equivalent to adjusting the oil discharge amount of the oil pump 81.

  The oil control valve 84 is a linear solenoid valve. The oil control valve 84 adjusts the flow rate of oil supplied to the pressure chamber 81m according to the duty ratio (= {energization time / (energization time + non-energization time)} × 100%) of the input control signal. The smaller the duty ratio, the smaller the amount of oil supplied to the pressure chamber 81m. Therefore, as shown in FIG. 10, the oil discharge amount (pump flow rate) increases as the duty ratio decreases. When the duty ratio is zero, the oil discharge amount is the maximum amount.

  The second communication path 52 communicates with the third communication path 53, and the oil in the main gallery 50 flows into the third communication path 53 through the second communication path 52. The oil that has flowed into the third communication path 53 passes through the third communication path 53, the first oil supply path 55 located on the intake side of the cylinder head 1, and the second oil supply path 56 and the third oil supply located on the exhaust side. The oil is distributed to the path 57 and the fourth oil supply path 58 and the fifth oil supply path 59 located in the vicinity of the specific cylinder.

  In the first oil supply passage 55, the oil supply portions 91 and 92 of the intake-side camshaft 41, the pivot mechanism 45c of the high-function HLA 45a, the standard HLA 45b, the intake-side oil shower 48, and the intake-side VVT 17 slide. The oil supply part 93 of the part is connected.

  Oil supply portions 94 and 95 of the exhaust camshaft 42, a pivot mechanism 46c of the high-function HLA 46a, a standard HLA 46b, and an oil shower 49 on the exhaust side are connected to the second oil supply path 56.

  An exhaust side VVT 18 (specifically, a retarded working chamber 18e and an advanced working chamber 18f) and an exhaust camshaft are connected to the third oil supply passage 57 via an oil filter 57a and a first direction switching valve 96. The amount of oil supplied to the retarded working chamber 18e and the advanced working chamber 18f can be adjusted by opening and closing the first direction switching valve 96, to which the oil supply section 94 of 42 is connected. . That is, the operation of the exhaust side VVT 18 is controlled by the first direction switching valve 96.

  The fourth oil supply path 58 is connected to the valve stop mechanisms 45d and 46d of the high function HLA 45a and 46a of the first cylinder via the oil filter 58a and the second direction switching valve 97. The amount of oil supplied to the first cylinder valve stop mechanisms 45 d and 46 d is adjusted by the second direction switching valve 97. That is, the operation of the valve stop mechanisms 45d and 46d of the first cylinder is controlled by the second direction switching valve 97.

  The fifth oil supply passage 59 is connected to the valve stop mechanisms 45d and 46d of the high function HLA 45a and 46a of the fourth cylinder via the oil filter 59a and the third direction switching valve 98. The amount of oil supplied to the valve stop mechanisms 45d and 46d of the fourth cylinder is adjusted by the third direction switching valve 98. That is, the operation of the valve stop mechanisms 45d and 46d of the fourth cylinder is controlled by the third direction switching valve 98.

  The oil supplied to each part of the engine 100 is cooled and lubricated, then dropped into the oil pan 3 through a drain oil passage (not shown), and sucked again by the oil pump 81. In this way, the hydraulic control device supplies the oil at a predetermined hydraulic pressure to the hydraulic actuator and the circulating portion of the engine 100 while circulating the oil.

  Note that pressure loss due to frictional resistance or the like occurs in the oil flowing through the hydraulic path, and therefore the downstream hydraulic pressure tends to be lower than the upstream side. And as the path becomes longer, the amount of decrease tends to increase. Also, the longer the path, the worse the responsiveness of the hydraulic pressure. Therefore, even if the discharge amount of the oil pump 81 is changed, it is not always possible to ensure the necessary hydraulic pressure in all hydraulic actuators.

(controller)
The controller 60 is a PCM (Powertrain Control Module) based on a well-known microcomputer, and includes hardware such as a processor and a memory, and software such as a control program and control data. The entire engine 100 is comprehensively controlled. As shown in FIG. 4, various sensors 50 a and 61 to 65 are connected to the controller 60. The sensors 50 a and 61 to 65 output signals indicating the respective detection results to the controller 60.

  For example, in addition to the above-described hydraulic sensor 50a, a crank angle sensor 61 that detects the rotation angle of the crankshaft 26, an airflow sensor 62 that detects the flow rate of air taken in by the engine 100, and an oil that detects the temperature of oil flowing through the hydraulic path. Signals are input to the controller 60 from a temperature sensor 63, a cam angle sensor 64 that detects the rotational phase of each of the intake cam shaft 41 and the exhaust cam shaft 42, a water temperature sensor 65 that detects the temperature of cooling water of the engine 100, and the like. The

  The controller 60 acquires the engine rotation speed based on the signal from the crank angle sensor 61, acquires the engine load based on the signal from the air flow sensor 62, and based on the signal from the cam angle sensor 64, the intake side VVT 17 and The operating angle of the exhaust side VVT 18 is acquired.

  Based on these, the controller 60 determines the operating state of the engine 100, and calculates the control amount of each actuator based on the determined operating state. Then, the controller 60 generates a control signal corresponding to the calculated control amount, and outputs the control signal to the first direction switching valve 96, the second direction switching valve 97, the third direction switching valve 98, and the oil control valve. Output to 84 etc. The controller 60 controls the operation of the engine 100 via these actuators.

  Hereinafter, control related to the above-described hydraulic control device among the controls performed by the controller 60 will be described in detail.

<Hydraulic control>
The controller 60 adjusts the discharge amount (oil discharge amount) of the oil pump 81 by outputting a control signal to the oil control valve 84. The controller 60 controls the hydraulic pressure supplied to each hydraulic actuator such as the valve stop mechanisms 45d and 46d by adjusting the oil discharge amount via the control signal.

  Specifically, the controller 60 generates and outputs a control signal such that the hydraulic pressure detected by the hydraulic pressure sensor 50a becomes a hydraulic pressure (target hydraulic pressure) set according to the operating state of the engine 100, and outputs an oil control valve. The oil discharge amount of the oil pump 81 is adjusted through opening adjustment of 84. Hereinafter, such hydraulic control is referred to as “feedback control”. By controlling the oil pressure in this way, for example, the oil pressure (transient oil pressure) necessary for the operation of the valve stop mechanisms 45d and 46d can be secured, and the engine 100 can be shifted from the full cylinder operation to the reduced cylinder operation.

  First, setting of the target hydraulic pressure will be described.

  In the hydraulic control device, oil is supplied to a plurality of hydraulic actuators by one oil pump 81 to ensure the hydraulic pressure (required hydraulic pressure) required by these hydraulic actuators. Different in hydraulic actuator. For example, in the engine 100, the required oil pressures of the exhaust side VVT 18, the first and fourth cylinder valve stop mechanisms 45d and 46d, and the oil jet 71 are relatively large. Further, the required oil pressure changes according to the operating state of engine 100.

  Therefore, in this engine 100, in order to ensure the required hydraulic pressure of all hydraulic actuators, the target hydraulic pressure is set to the exhaust side VVT 18, the valve stop mechanisms 45d and 46d, and the oil jet 71 for each operating state of the engine 100. It is necessary to set it above the maximum value of each required oil pressure.

  There is also a required oil pressure at the lubrication site of engine 100 such as a bearing portion, and the required oil pressure also changes according to the operating state of engine 100. Since the required hydraulic pressure of the bearing portion 29 that supports the crankshaft 26 is relatively high at the lubrication site of the engine 100, a hydraulic pressure that is slightly higher than the required hydraulic pressure is set as the hydraulic pressure (base hydraulic pressure) required for the lubrication site. Yes.

  In the feedback control described above, the controller 60 sets the target hydraulic pressure so that both the required hydraulic pressure and the base hydraulic pressure of each hydraulic actuator are satisfied with a necessary and sufficient value. Thereby, while supplying oil at an appropriate hydraulic pressure to the hydraulic control system of the engine 100, the drive of the oil pump 81 is minimized and fuel consumption is suppressed.

  The base oil pressure and the required oil pressure change according to the operating state of the engine 100, for example, the load and rotation speed of the engine 100, and the oil temperature. Therefore, the controller 60 stores a map of base oil pressure and required oil pressure corresponding to these in the memory.

  FIG. 5 shows a map of the base oil pressure. The “running state”, “rotation speed”, “load”, and “oil temperature” on the first line of the map represent specifications, and numbers such as “500” on the right side of “oil temperature” A rotational speed (rpm) of 100 is represented. The unit of the numerical value of the base hydraulic pressure is kPa.

  Note that FIG. 5 shows a simplified map for convenience, and a normal map is set in a more detailed manner. Also, in the map, the base hydraulic pressure value is set discretely according to the rotation speed, etc., so the numerical value in the rotation speed that is not set in the map is linearly interpolated with the value set in the map. (The same applies to the following maps).

  As shown in FIG. 5, the base hydraulic pressure is set according to the oil temperature (Ta1> Ta2> Ta3) and the rotational speed of engine 100. Since the lubrication at the bearing portion is required as the rotational speed increases, the base hydraulic pressure is set so as to increase as the rotational speed increases. When the rotation speed is in the middle rotation region, the base oil pressure is set to be a substantially constant value. When the rotation speed is in the low rotation region, the base oil pressure is set to decrease as the oil temperature decreases. Has been.

  FIG. 6 shows a map of required oil pressure at the time of request for lubrication improvement. The demand for lubrication improvement is issued mainly during idle operation. In an idle operation state, the generation of oil mist tends to decrease, and lubrication by the oil mist of the connecting rod 25 and the like may be insufficient. Therefore, the oil pressure is increased by the demand for lubrication improvement to increase the generation of oil mist.

  Specifically, as shown in FIG. 6, a request for improvement in lubrication is issued when “the vehicle speed is S0 or less” and “the accelerator is fully closed”. Therefore, the required oil pressure is set only when the rotational speed of engine 100 is relatively low. The required oil pressure at the time of request for lubrication improvement is set to increase as the oil temperature (Tb1> Tb2> Tb3> Tb4) decreases. This is because as the oil temperature decreases, the viscosity of the oil increases and the generation of oil mist decreases.

  In FIG. 6, the required hydraulic pressure is constant even when the rotational speed is different, but the required hydraulic pressure may be changed according to the rotational speed. For example, the required oil pressure may be set higher as the rotational speed becomes higher.

  FIG. 7 shows a map of the required oil pressure of the oil jet 71. The operation condition of the oil jet 71 is defined according to the rotational speed and load of the engine 100. Since the oil jet 71 injects oil when the check valve is opened, the required oil pressure is constant.

  FIG. 8 shows a map of the required oil pressure of the exhaust side VVT 18. The required oil pressure of the exhaust side VVT 18 is set according to the oil temperature and the rotational speed of the engine 100. The required oil pressure is set to increase as the engine rotational speed increases, and is set to decrease as the oil temperature (Tc1 <Tc2 <Tc3) decreases.

  A map of required oil pressure (maintenance oil pressure, transient oil pressure) of the valve stop mechanisms 45d and 46d is also stored in the memory, which will be described later.

(Specific examples of hydraulic control)
The hydraulic feedback control will be described with reference to FIG. This feedback control is performed by the controller 60 controlling the flow rate (oil discharge amount) of the oil pump 81.

  The controller 60 collates the rotation speed of the engine 100 and the oil temperature with the base oil pressure map to obtain the base oil pressure. In addition, the controller 60 obtains the exhaust side VVT 18, the valve stop mechanisms 45d and 46d, the oil jet 71, and the required hydraulic pressure at the time of request for lubrication improvement by referring to the corresponding map. Then, the controller 60 extracts the maximum value from the base oil pressure and these required oil pressures, and sets the maximum value as the target oil pressure.

  Next, the controller 60 calculates the corrected target hydraulic pressure by increasing the target hydraulic pressure based on the hydraulic pressure reduction allowance when the oil flows from the oil pump 81 to the position of the hydraulic pressure sensor 50a. The oil pressure reduction allowance is stored in advance in the memory. The controller 60 converts the corrected target hydraulic pressure into the flow rate (oil discharge amount) of the oil pump 81, and acquires the target flow rate (target discharge amount).

  Subsequently, the controller 60 corrects the target flow rate based on the consumption flow rate of each hydraulic actuator. Specifically, the controller 60 converts a predicted operation amount of the exhaust side VVT 18 when operating the exhaust side VVT 18 into a flow rate, and obtains a flow rate (consumption flow rate) consumed when the exhaust side VVT 18 is operated. The predicted operation amount of the exhaust side VVT 18 can be obtained from the difference between the current operation angle and the target operation angle, and the rotational speed of the engine 100. Further, the controller 60 converts the predicted operation amount of the valve stop mechanisms 45d and 46d when the valve stop mechanisms 45d and 46d are operated into a flow rate, and obtains the consumed flow rate when the valve stop mechanisms 45d and 46d are operated. Further, the controller 60 obtains a consumption flow rate when the oil jet 71 is operated. As described above, the controller 60 obtains the consumed flow rate corresponding to the hydraulic actuator to be operated, and corrects the target flow rate using the consumed flow rate.

  Further, the controller 60 corrects the target flow rate based on the hydraulic feedback amount. When the oil discharge amount increases or decreases, the oil pressure (actual oil pressure) detected by the oil pressure sensor 50a follows the change in the target oil pressure with a delay due to the response delay of the oil pump 81. Such a change in the actual oil pressure due to a response delay of the oil pressure can be predicted in advance by experiments or the like, and the oil pressure predicted in this manner (predicted oil pressure) is stored in the memory. The controller 60 obtains a value (hydraulic feedback amount) corresponding to the deviation between the predicted oil pressure and the actual oil pressure, and corrects the target flow rate using the oil pressure feedback amount. Thereby, the actual hydraulic pressure can be smoothly matched with the target hydraulic pressure.

  The controller 60 sets the target duty ratio by comparing the target flow rate corrected in this way (corrected target flow rate) and the rotation speed of the engine 100 with the duty ratio map, and the control signal is oil-controlled. Transmit to valve 84. Thereby, the oil pump 81 discharges oil by a predetermined amount, and the hydraulic pressure in the hydraulic path (particularly the main gallery 50) is adjusted so as to become the target hydraulic pressure.

  FIG. 10 shows the characteristics of the oil pump 81. As shown in this figure, when the rotational speed of the engine 100 increases, the oil discharge amount increases even if the duty ratio is the same as the flow rate of oil discharged from the oil pump 81 per unit time increases. Thus, the pump discharge amount is defined according to the rotational speed of the engine 100 and the duty ratio of the control signal. In other words, by obtaining the rotational speed of the engine 100 and the target flow rate of the pump discharge amount, it is possible to set the target duty ratio necessary for realizing the target flow rate.

<Control of the number of cylinders>
In this engine 100, all cylinders (first to fourth cylinders) are operated by operating all cylinders (first to fourth cylinders) according to the operating state, and some cylinders (first and fourth cylinders). Is switched to a reduced-cylinder operation in which combustion is performed in the remaining cylinders (second cylinder and third cylinder).

  Specifically, as shown in FIG. 11, when the operating state of engine 100 is in the reduced cylinder operating region, the reduced cylinder operation is executed. Further, when the operating state of the engine 100 is outside the reduced cylinder operating region, the all cylinder operation is executed.

  For example, when the engine 100 accelerates with a predetermined load (L0 or less) and the rotation speed increases, all cylinder operation is performed when the rotation speed is less than V1, and reduced cylinder operation is performed when the rotation speed becomes V1 or more. Further, for example, when the rotational speed decreases by decelerating at a predetermined engine load (L0 or lower), all cylinder operation is executed when the rotational speed exceeds V2, and reduced cylinder operation is executed when V2 or lower.

  The rotational speeds V1 and V2 and the load L0 that define the boundary between the all-cylinder operation region and the reduced-cylinder operation region are respectively defined based on the performance requirements of the engine 100. For example, the rotational speed V1 that divides the reduced-cylinder operation region from the lower-rotation side operation region is the NVH performance due to the influence of vibration or the like when the reduced-cylinder operation is performed on the lower rotation side than the rotation speed V1. Is defined as a boundary that cannot be sufficiently secured. On the other hand, the rotational speed V2 that divides the reduced-cylinder operation region and the higher-rotation side operation region is the erroneous opening of the exhaust valve 14 when the reduced-cylinder operation is performed on the higher rotation side than the rotation speed V2. Is defined as a boundary in which the reliability of the engine 100 is not sufficiently secured. Further, the load L0 that divides the reduced-cylinder operation region and the operation region on the higher load side than that is sufficient to ensure the fuel efficiency of the engine 100 when the reduced-cylinder operation is performed on the higher load side than the load L0. It is defined as the boundary that will not be done.

  Although illustration is omitted, all-cylinder operation and reduced-cylinder operation can be switched according to the water temperature or the oil temperature. For example, when the engine 100 runs at a predetermined rotational speed and a predetermined load, the engine 100 warms up and the water temperature rises, when the water temperature is lower than the predetermined temperature, the all-cylinder operation is executed and the water temperature is predetermined. When the temperature is higher than the temperature, the reduced cylinder operation is executed. Switching according to the oil temperature will be described later.

  The controller 60 controls the hydraulic pressure by the above-described feedback control at the time of steady operation of all cylinder operation and reduced cylinder operation. On the other hand, at the time of transition from full-cylinder operation to reduced-cylinder operation, the hydraulic pressure can be increased in order to ensure the hydraulic pressure (transient hydraulic pressure) necessary for the operation of the valve stop mechanisms 45d and 46d (pressing of the lock pin 45g). Required. Therefore, in this engine 100, feedback control and maximum discharge control described later are used properly according to the operating state of engine 100. After the transient oil pressure is ensured by any of the controls, the controller 60 outputs the control signal to the second direction switching valve 97 and the third direction switching valve 98 to thereby control the pressurized oil. It supplies to the stop mechanisms 45d and 46d. The valve stop mechanisms 45d and 46d operate by receiving the supplied oil, thereby executing switching from the full cylinder operation to the reduced cylinder operation.

<Hydraulic control during reduced cylinder operation>
By the way, in the reduced cylinder operation, the valve stop mechanisms 45d and 46d are maintained in the unlocked state, that is, the state where the lock pin 45g is pushed into the outer cylinder 45e against the urging force of the lock spring 45h. At this time, the required hydraulic pressure (also referred to as maintenance hydraulic pressure) of the valve stop mechanisms 45d and 46d becomes larger than that during all cylinder operation.

  On the other hand, when there is a request to change the opening / closing timing of the exhaust valve 14 during the reduced-cylinder operation and the exhaust-side VVT 18 operates, pressurized oil is supplied to the advance working chamber 18f and the retard working chamber 18e. Supplied. As a result, the oil consumption increases and the hydraulic pressure temporarily decreases in the hydraulic path (main gallery 50), so there is a possibility that the maintenance hydraulic pressure cannot be secured.

  Therefore, the inventors of the present application focused on the fact that the amount of decrease in hydraulic pressure is proportional to the operating speed of the exhaust side VVT 18. That is, engine 100 is configured to suppress the amount of decrease in hydraulic pressure by limiting the operating speed of exhaust side VVT 18.

  However, if the operating speed of the exhaust side VVT 18 is excessively limited, there is a risk of adversely affecting the driving performance during the reduced cylinder operation. Therefore, the operating speed of the exhaust side VVT 18 is limited within a range that does not affect the driving performance. As long as it is limited within such a range, simply considering the operating speed of the exhaust-side VVT 18 may cause problems in securing the maintenance hydraulic pressure of the valve stop mechanisms 45d and 46d.

  Therefore, in this engine 100, in addition to limiting the operating speed of the exhaust side VVT 18, the target hydraulic pressure is adjusted by adding the amount of decrease in the hydraulic pressure due to the operation of the exhaust side VVT 18.

  However, in this case, in order to stably secure the maintenance hydraulic pressure, the target hydraulic pressure must be set to a high value with a margin, and an increase in fuel consumption is inevitable. Therefore, in this engine 100, in order to suppress an increase in fuel consumption, the setting of the maintenance oil pressure is changed according to the viscosity of the oil.

  That is, the second communication path 52, the oil filter 57a, and the first filter 50 are provided between the main gallery 50, which is used as a reference for hydraulic control such as adjustment of the target hydraulic pressure, and the exhaust side VVT 18 that requires maintenance hydraulic pressure. A direction switching valve 96 or the like is interposed, and the path between them is also long.

  On the other hand, the oil temperature changes according to the operating state of the engine 100, and the viscosity of the oil changes accordingly. As the viscosity of the oil increases, the fluidity becomes worse and the pressure loss increases. For this reason, when the oil viscosity increases, the response of the hydraulic control of the exhaust side VVT 18 decreases. Therefore, if the increase in the hydraulic pressure due to the operation of the exhaust side VVT 18 is set to the minimum necessary, the maintenance hydraulic pressure is temporarily May not be secured.

  Therefore, in this engine 100, a map is introduced in which the required oil pressure (maintenance oil pressure) of the valve stop mechanisms 45d and 46d during the reduced cylinder operation can be set according to the oil temperature. Accordingly, even if the target hydraulic pressure is adjusted by changing the setting of the maintenance hydraulic pressure in accordance with the viscosity of the oil and setting the additional amount of the hydraulic pressure drop due to the operation of the exhaust side VVT 18 to the minimum necessary, the maintenance hydraulic pressure Can be secured stably.

  The map (maintenance hydraulic pressure map) is shown in the upper part of FIG. The horizontal axis represents the oil temperature (oil temperature, unit: ° C.) detected by the oil temperature sensor 63, and the vertical axis represents the required oil pressure (maintenance oil pressure, unit: kpa).

  The viscosity of the oil changes according to the oil temperature, and the viscosity increases as the oil temperature decreases. Therefore, in this maintenance oil pressure map, the maintenance oil pressure corresponding to the oil temperature (viscosity) is set. Specifically, when the oil temperature is lower than the predetermined temperature T0, the maintenance oil pressure is set higher than when the oil temperature is equal to or higher than T0.

  In this maintenance oil pressure map, even if the rotation speed of engine 100 changes, if the oil temperature is the same, the maintenance oil pressure is set to be constant.

<Hydraulic control when switching from full cylinder operation to reduced cylinder operation>
As described above, at the time of transition from the full cylinder operation to the reduced cylinder operation, the hydraulic pressure (transient hydraulic pressure) necessary for the operation of the valve stop mechanisms 45d and 46d (the pushing operation of the lock pin 45g, also called pin lock) is secured. In addition, it is required to increase the hydraulic pressure.

  However, when switching from the full cylinder operation to the reduced cylinder operation, it is necessary to complete the pin lock within a predetermined time according to the operation of the exhaust valve 14. That is, in order to quickly and stably switch from the full cylinder operation to the reduced cylinder operation, it is conceivable to reduce the variation in the response time of the valve stop mechanisms 45d and 46d as much as possible.

  The variation in response time is caused by disturbance such as air mixed in the hydraulic path. In this case, the response time becomes longer according to the time required for air to be crushed by hydraulic pressure. The time required to crush the air increases as the fluidity of the oil decreases (that is, the time increases as the viscosity of the oil increases). In order to shorten this time, it can be considered that the transient oil pressure is set relatively high and the air is crushed as quickly as possible.

  Further, as the rotational speed of engine 100 increases, it is required to complete pin lock more quickly. That is, since the operating speed of the exhaust valve 14 is linked to the rotational speed of the engine 100, when the rotational speed increases, the time allowed for pin locking decreases. Therefore, when the rotational speed of the engine 100 is high, the valve stop mechanisms 45d and 46d are required to have a smaller variation in response time than when the rotational speed is low.

  Therefore, in this engine 100, a map that can set the required oil pressure (transient oil pressure) necessary for the pin lock in accordance with the oil temperature (viscosity) and the rotation speed of the engine 100 is introduced, and variation in response time is made as much as possible. I tried to make it smaller. By doing so, it is possible to quickly and stably switch from the full cylinder operation to the reduced cylinder operation.

  The lower part of FIG. 12 shows the map (transient oil pressure map). The horizontal axis represents the oil temperature (oil temperature, unit: ° C.) detected by the oil temperature sensor 63, and the vertical axis represents the required oil pressure (transient oil pressure, unit: kpa). As shown in this figure, the transient oil pressure is set to be substantially larger than the maintenance oil pressure.

  The viscosity of the oil increases as the oil temperature decreases. The higher the viscosity of the oil, the longer it takes to crush the air. This time can be shortened by setting the transient oil pressure high. Therefore, in this transient oil pressure map, the transient oil pressure is set to increase as the oil temperature decreases.

  Also, in this transient oil pressure map, unlike the maintenance oil pressure map, the transient oil pressure is set to increase as the rotational speed of engine 100 increases.

  However, when the above-described feedback control is used to secure such a transient oil pressure, the responsiveness of the valve stop mechanisms 45d and 46d may be lowered depending on the oil temperature of the oil supplied to the valve stop mechanisms 45d and 46d. The inventors of the present application have noticed.

  That is, for example, when the oil temperature is high, the amount of leakage from the sliding portion and the like increases due to the lower viscosity of the oil, making it difficult to increase the hydraulic pressure. In this case, for example, by repeatedly performing the feedback control, the oil discharge amount is gradually increased, so that the time required to secure the transient hydraulic pressure becomes longer. Considering that the transient hydraulic pressure is relatively high, it is difficult to operate the valve stop mechanisms 45d and 46d with good response.

  On the other hand, when the oil temperature is low, the amount of leakage is suppressed, but the flow resistance increases as the oil viscosity increases, so that the hydraulic response becomes worse depending on the length of the hydraulic path. In this case, since the oil pressure in the vicinity of the valve stop mechanisms 45d and 46d rises with a delay, it is difficult to operate the valve stop mechanisms 45d and 46d with good response as in the case where the oil temperature is high.

  If there is a delay in the operation of the valve stop mechanisms 45d and 46d, it is inconvenient to quickly switch from full cylinder operation to reduced cylinder operation. This is not preferable for reducing the fuel consumption of the engine 100.

  Therefore, in this engine 100, when the transient oil pressure is ensured in order to operate the valve stop mechanisms 45d and 46d, the above-described feedback control and the oil discharge amount are maximized according to the detection result of the oil temperature sensor 63. The maximum discharge control to be set is properly used.

  Specifically, when the controller 60 operates the valve stop mechanisms 45d and 46d, the oil temperature detected by the oil temperature sensor 63 falls within a predetermined range (specifically, the second region B in FIG. 13). In some cases, feedback control is performed, and when it is out of the range, maximum discharge control is performed.

  Here, in the present embodiment, the maximum discharge control is realized by setting the duty ratio of the control signal output to the oil control valve 84 to zero.

  In order to realize proper use of the feedback control and the maximum discharge control, the engine 100 is introduced with a map that allows the control to be performed at the time of operating the valve stop mechanisms 45d and 46d to be selected according to the operating state of the engine 100. Yes. By selecting the control suitable for the operating state, the hydraulic pressure is appropriately controlled, and as a result, both the responsiveness of the valve stop mechanisms 45d and 46d and the fuel efficiency can be achieved.

  FIG. 13 shows the map. The horizontal axis represents the rotational speed (unit: rpm) of the engine 100, and the vertical axis represents the temperature of the oil (oil temperature, unit: ° C.) detected by the oil temperature sensor 63.

  As shown in FIG. 13, when the controller 60 operates the valve stop mechanisms 45d and 46d, when the oil temperature detected by the oil temperature sensor 63 is equal to or lower than a predetermined first threshold L1 (is in the first region A). Time), maximum discharge control (Full discharge) is performed.

  Here, the first threshold value L1 is a temperature that divides the first region A and the second region B, and is set to be a constant temperature T1 regardless of the rotational speed of the engine 100.

  When the oil temperature detected by the oil temperature sensor 63 exceeds the first threshold value L1 and is lower than the second threshold value L2 set higher than the first threshold value L1 (specifically, the engine 100). (When the operating state of the engine 100 is in the second region B), the feedback control is performed, and when the operating state of the engine 100 is in the third region C (specifically, when the operating state of the engine 100 is in the third region C). Performs maximum discharge control.

  Here, the second threshold value L2 is a temperature that separates the second region B and the third region C, and is set to be higher when the rotational speed of the engine 100 is high than when it is low. Specifically, the second threshold L2 is a predetermined temperature T2 (> T1) at the rotation speed V1. Therefore, even when the oil temperature is the same (particularly when the oil temperature is equal to or higher than T2 and lower than T3), when the rotational speed of the engine 100 is relatively low (for example, when the rotational speed is near V1). While maximum ejection control is performed, feedback control may be performed when the rotational speed is higher than that (for example, when the rotational speed is near V2).

  Furthermore, when the controller 60 operates the valve stop mechanisms 45d and 46d, when the oil temperature detected by the oil temperature sensor 63 is equal to or higher than the third threshold L3 set higher than the second threshold L2 (specifically, When the operating state of the engine 100 is in the fourth region D), the switching to the reduced cylinder operation is stopped and the all cylinder operation is performed. At this time, the controller 60 performs normal feedback control.

  Here, the third threshold L3 is a temperature that separates the third region C and the fourth region D, and is set to be higher when the rotational speed of the engine 100 is high than when it is low. Specifically, the third threshold L3 is a predetermined temperature T3 (> T2) at the rotation speed V1. Therefore, even when the oil temperature is the same (particularly when the oil temperature is equal to or higher than T3), all-cylinder operation is performed when the rotation speed of the engine 100 is sufficiently low (for example, when the rotation speed is near V1). When the rotation speed is higher than that (for example, when the rotation speed is near the center value of V1 and V2), switching to the reduced cylinder operation is performed by the maximum discharge control, and the rotation speed is further higher than that. Sometimes (for example, when the rotation speed is near V2), switching to the reduced cylinder operation may be performed by feedback control.

<Specific flow of hydraulic control>
FIG. 14 illustrates a change in hydraulic pressure (actual hydraulic pressure) at the time of switching from full cylinder operation to reduced cylinder operation. FIG. 15 illustrates a flowchart of processing related to the branching between feedback control and maximum discharge control and processing related to feedback control in hydraulic control, and FIG. 16 illustrates a flowchart of processing related to maximum discharge control. Hereinafter, a specific flow of hydraulic control will be described with reference to FIGS.

  The controller 60 starts the hydraulic control with the start of the engine 100 (step S1: YES), and ends the hydraulic control with the stop of the engine 100 (step S1: NO).

  When the hydraulic control is started, the controller 60 reads the load, rotation speed, oil temperature, and water temperature of the engine 100 in order to grasp the operating state of the engine 100 (step S2).

  Next, based on the content read in step S2, whether to continue all cylinder operation, switch from all cylinder operation to reduced cylinder operation, or maintain reduced cylinder operation is executed for engine 100. Determination is made (step S3 to step S8). In particular, when the controller 60 according to the present embodiment determines to perform switching from all-cylinder operation to reduced-cylinder operation, the controller 60 determines whether to perform normal feedback control or to perform maximum discharge control instead of feedback control. A determination process (step S7) is performed.

  First, the controller 60 determines whether or not the first cylinder and the fourth cylinder are in a stopped state, that is, whether or not the reduced cylinder operation is in progress (step S3).

  When it is determined that the reduced cylinder operation is being performed (step S3: YES), the controller 60 determines whether the cylinder stop condition is satisfied (step S4). This determination is made based on the information read in step S2. Here, when the controller 60 determines that the cylinder stop condition is satisfied (step S4: YES), as shown in P1 of FIG. 14, based on the maintenance hydraulic pressure map, the controller 60 continues the reduced cylinder operation. The maintenance oil pressure corresponding to the oil temperature at the time is read (step S5), and the process proceeds to step S9.

  On the other hand, when it is determined that the cylinder stop condition is not satisfied (step S4: NO), the controller 60 performs step S5 to return from the reduced cylinder operation to the all cylinder operation, as indicated by P2 in FIG. Skip to step S9.

  On the other hand, when the controller 60 determines that the first cylinder and the fourth cylinder are not in a stopped state, that is, during the operation of all cylinders (step S3: NO), the controller 60 sets the cylinder stop condition in the same manner as in step S4. It is determined whether or not this is true (step S6). If the controller 60 determines that the cylinder is in a stopped state (step S6: YES), the controller 60 proceeds to step S7 in order to switch from all-cylinder operation to reduced-cylinder operation, as indicated by P3 in FIG. move on.

  In step S <b> 7, the controller 60 determines whether or not maximum discharge control (Full discharge) is necessary based on the operating state of the engine 100. Specifically, the controller 60 determines whether the operating state of the engine 100 is in the first region A to the fourth region D. Here, when it is determined that it is in the second region B, that is, when it is determined that the maximum discharge control is not necessary (step S7: NO), the controller 60 continues switching from the all cylinder operation to the reduced cylinder operation. At the same time, in order to perform normal feedback control, based on the transient oil pressure map, the transient oil pressure corresponding to the oil temperature and rotation speed at that time is read (step S8), and the process proceeds to step S9. On the other hand, when the operating state of the engine 100 is in the fourth region D, the detailed flow is omitted, but the switching from the all-cylinder operation to the reduced-cylinder operation is stopped and the normal feedback control is performed. Proceed from step S6 to step S9. On the other hand, when it is determined that it is in the first region A or the third region C, that is, when it is determined that it is necessary to perform the maximum discharge control instead of the feedback control (step S7: YES), the controller 60 Proceeding to step S22 shown in FIG. 16, the maximum discharge control is started. The flow at this time will be described later.

  On the other hand, when it is determined that the cylinder stop condition is not satisfied (step S6: NO), the controller 60 skips steps S7 to S8 to continue the all-cylinder operation as shown in P4 of FIG. Then, the process proceeds to step S9.

  The processing performed from step S9 to step S21 is processing that constitutes hydraulic pressure feedback control.

  First, the controller 60 determines whether or not the operating conditions of the hydraulic actuators such as the exhaust side VVT 18, the valve stop mechanisms 45d and 46d, and the oil jet 71 and the conditions for requesting the lubrication improvement are satisfied (step). S9).

  If neither the operating condition of each hydraulic operating device nor the condition for requesting lubrication improvement is satisfied (step S9: NO), the controller 60 determines the rotational speed of the engine 100 from the base hydraulic pressure map. A base oil pressure corresponding to the oil temperature is obtained (step S11).

  On the other hand, when the operating condition of each hydraulic actuator or the condition for requesting lubrication improvement is satisfied (step S9: YES), the controller 60 satisfies the conditions before proceeding to step S11. The required oil pressure corresponding to the operating device or the required oil pressure for lubrication improvement is read from the map (step S10).

  Then, the controller 60 compares the base oil pressure, the required oil pressure, the maintenance oil pressure, and the transient oil pressure, and sets the highest oil pressure as the target oil pressure (step S12). Of the requested hydraulic pressure, the maintenance hydraulic pressure, and the transient hydraulic pressure, those that have not been read (when not passing through step S5 or step S8) are excluded from comparison targets. For example, when none of the required oil pressure, the maintenance oil pressure, and the transient oil pressure is read, the controller 60 sets the base oil pressure to the target oil pressure. Further, at the time of reduced cylinder operation or at the time of switching from all cylinder operation to reduced cylinder operation, the maintenance oil pressure and the transient oil pressure become the highest oil pressure, and these are set as the target oil pressure.

  Subsequently, the controller 60 calculates a corrected target oil pressure by adding a hydraulic pressure reduction margin to the target oil pressure (step S13), and converts the corrected target oil pressure into a flow rate to obtain a target flow rate (target discharge amount) (step S14). ). Furthermore, the controller 60 corrects the target flow rate by adding the consumption flow rate of each hydraulic actuator that operates (step S15).

  Then, the controller 60 sets the target duty ratio by comparing the corrected target flow rate with the duty ratio map (step S16). The controller 60 reads the duty ratio of the current control signal (hereinafter referred to as “current duty ratio”), and determines whether or not the current duty ratio matches the target duty ratio (step S17).

  If the current duty ratio does not match the target duty ratio (step S17: NO), the controller 60 changes the duty ratio of the control signal to the target duty ratio and outputs the control signal to the oil control valve 84 (step). S18). Thereafter, the controller 60 proceeds to step S19. On the other hand, when the current duty ratio matches the target duty ratio (step S17: YES), the controller 60 skips step S18 and proceeds to step S19.

  In step S19, the controller 60 reads the hydraulic pressure (actual hydraulic pressure) of the hydraulic pressure sensor 50a. Then, the controller 60 determines whether or not the actual oil pressure matches the target oil pressure set in step S12 (step S20).

  When the actual hydraulic pressure and the target hydraulic pressure do not match (step S20: NO), the controller 60 adjusts the duty ratio of the control signal based on the deviation between the actual hydraulic pressure and the target hydraulic pressure, and the control signal is sent to the oil control valve. (Step S21). Thereafter, the controller 60 returns to step S19. That is, the controller 60 repeats step S19 to step S21 until the actual hydraulic pressure and the target hydraulic pressure match. On the other hand, when the actual hydraulic pressure and the target hydraulic pressure coincide with each other (step S20: YES), the controller 60 returns to the initial stage of the hydraulic pressure control again, and executes the processes described above from step S1.

  On the other hand, when it is determined YES in step S7, that is, when maximum discharge control is performed instead of feedback control, the controller 60 performs the processing related to step S22 to step S24 in FIG.

  Specifically, the controller 60 sets the duty ratio of the control signal to zero (step S22), and outputs the control signal to the oil control valve 84 (step S23). As described above, when the duty ratio is zero, the oil discharge amount becomes the maximum amount.

  Subsequently, in step S24, the controller 60 determines whether or not the first cylinder and the fourth cylinder are in a stopped state. It is determined whether or not the switching from the all cylinder operation to the reduced cylinder operation has been completed. The controller 60 repeats the determination according to step S23 until it is determined that this switching is completed.

  If the controller 60 determines that the switching from the all cylinder operation to the reduced cylinder operation has been completed (step S24: YES), the controller 60 proceeds to step S4 shown in FIG. Thereafter, the controller 60 executes a process related to maintaining the reduced cylinder operation or executes a process for returning from the reduced cylinder operation to the all cylinder operation in accordance with the operating state of the engine 100.

<Summary>
As described above, in this hydraulic control device, when switching from the full cylinder operation to the reduced cylinder operation, as shown in the map of FIG. 13, instead of feedback control, maximum discharge is performed according to the oil temperature. Execute control. When the maximum discharge control is performed, the oil discharge amount of the oil pump 81 is set to the maximum amount regardless of the target oil pressure of the valve stop mechanisms 45d and 46d. Therefore, the oil pressure is increased as much as possible by increasing the oil discharge amount. It can be raised quickly. As a result, the valve stop mechanisms 45d and 46d can be operated with good response, so that the switching from the full-cylinder operation to the reduced-cylinder operation can be speeded up, and consequently the fuel consumption of the engine 100 can be reduced. Become.

  In addition, when the maximum discharge control is performed regardless of the oil temperature, the hydraulic pressure is increased more than necessary when the hydraulic pressure is in an operation range where the hydraulic pressure is relatively likely to rise, as in the second region B of FIG. May end up. In that case, there is a possibility that the drive loss of the oil pump 81 increases or the oil jet 71 is operated by excessive hydraulic pressure. Such a situation is undesirable for reducing fuel consumption.

  On the other hand, in this hydraulic control device, feedback control and maximum discharge control are selectively used based on the oil temperature. For example, in the operation region where the oil pressure is relatively likely to increase as in the second region B, feedback control suitable for obtaining the necessary minimum oil pressure is performed, while in the first region A and the third region C, for example. In the operation region where the hydraulic pressure is relatively difficult to increase, instead of such feedback control, maximum discharge control suitable for quickly increasing the hydraulic pressure is performed. By doing so, the response performance of the valve stop mechanisms 45d and 46d and the fuel efficiency performance of the engine 100 can be compatible.

  For example, when the oil temperature is lowered, the viscosity of the oil is increased, so that the flow resistance in the hydraulic path is increased and the oil is difficult to flow. For this reason, the hydraulic response is deteriorated according to the length of the hydraulic path. In this case, since the hydraulic pressure in the vicinity of the valve stop mechanisms 45d and 46d increases with a delay, it may be difficult to operate the valve stop mechanisms 45d and 46d with good response.

  On the other hand, in the hydraulic control apparatus, as shown in the first region A of FIG. 13, when the oil temperature is equal to or lower than the first threshold value L1, maximum discharge control is performed. As a result, the hydraulic pressure can be quickly raised, and the valve stop mechanisms 45d and 46d can be operated with good response. This is advantageous in reducing the fuel consumption of the engine 100.

  Moreover, since oil viscosity will become low if oil temperature becomes high to some extent, oil becomes easy to flow relatively. As a result, the delay in hydraulic pressure is eliminated, and it may be possible to operate the valve stop mechanisms 45d and 46d with good response without performing maximum discharge control.

  Therefore, in this hydraulic control device, as shown in the second region B of FIG. 13, when the oil temperature is between the first threshold value L1 and the second threshold value L2, feedback control is performed instead of the maximum discharge control. It has become. This is advantageous in suppressing an excessive increase in hydraulic pressure and, in turn, fuel consumption of engine 100.

  Further, as shown in the third region C of FIG. 13, when the oil temperature becomes sufficiently higher than the first threshold value L1, the viscosity of the oil decreases, so that the amount of oil leakage at the sliding portion such as the oil pump 81 is reduced. It will increase. If the amount of leakage increases, the hydraulic pressure is less likely to increase. Therefore, if the feedback control is performed, it may be difficult to operate the valve stop mechanisms 45d and 46d with good response.

  On the other hand, in this hydraulic control device, as shown in FIG. 13, when the oil temperature is equal to or higher than the second threshold value L2, maximum discharge control is performed instead of feedback control. As a result, the hydraulic pressure can be increased as quickly as possible, and the valve stop mechanisms 45d and 46d can be operated with good response. This is effective in suppressing fuel consumption of the engine 100.

  In addition, when the rotational speed of the engine 100 is increased, the flow rate of oil discharged from the oil pump 81 (oil discharge amount) is also increased, so that the influence of leakage is reduced. Therefore, when the rotational speed is high, the hydraulic pressure is more likely to increase than when the rotational speed is lower. In this case, if the maximum discharge control is performed, the fuel consumption may increase due to the drive loss of the oil pump 81 or the like.

  Therefore, as shown in FIG. 13, the second region B in which the feedback control is performed is expanded by setting the second threshold L <b> 2 higher as the rotational speed of the engine 100 becomes higher. By doing so, it becomes advantageous in suppressing the fuel consumption of the engine 100.

  When the oil temperature exceeds the second threshold value L2, the maximum discharge control is performed. When the oil temperature becomes sufficiently higher than the second threshold value L2, the influence of the leak becomes relatively large, so that the maximum discharge control is performed. However, transient oil pressure may not be secured.

  Therefore, in this hydraulic control apparatus, as shown in the fourth region D of FIG. 13, when the oil temperature is equal to or higher than the third threshold value L3, the switching to the reduced cylinder operation is canceled and the normal feedback control is performed without changing all cylinders. Continue driving. Thereby, engine 100 can be controlled appropriately.

100 Engine 45d Valve stop mechanism 46d Valve stop mechanism 81 Oil pump 84 Oil control valve 50a Oil pressure sensor 60 Controller 63 Oil temperature sensor L1 First threshold L2 Second threshold

Claims (4)

Hydraulic control of an engine having a plurality of cylinders and configured to switch between all-cylinder operation in which all of the plurality of cylinders are operated and reduced-cylinder operation in which some of the plurality of cylinders are deactivated A device,
A valve stop mechanism for switching the engine from the all-cylinder operation to the reduced-cylinder operation by receiving and operating pressurized oil;
An oil pump for supplying oil to the valve stop mechanism;
An oil control valve for adjusting an oil discharge amount of the oil pump;
The valve stop mechanism is connected to the oil control valve and outputs a control signal to the oil control valve and controls the oil pressure of oil supplied to the valve stop mechanism via the control signal. A controller to operate;
A hydraulic sensor connected to the controller and detecting a hydraulic pressure of oil supplied to the valve stop mechanism, and outputting a signal indicating the detection result to the controller;
An oil temperature sensor connected to the controller and detecting the oil temperature of the oil supplied to the valve stop mechanism, and outputting a signal indicating the detection result to the controller;
When the controller operates the valve stop mechanism,
When the oil temperature detected by the oil temperature sensor is within a predetermined range, the oil control valve is controlled so that the oil pressure detected by the oil pressure sensor becomes a target oil pressure set based on the operating state of the engine. While performing feedback control that outputs control signals,
When the oil temperature detected by the oil temperature sensor is outside the predetermined range, a control signal is output to the oil control valve so that the oil discharge amount is set to the maximum amount instead of the feedback control. Hydraulic control device for the engine that performs maximum discharge control. The engine hydraulic control device according to claim 1,
The controller, when operating the valve stop mechanism, performs the feedback control when the oil temperature detected by the oil temperature sensor exceeds a predetermined first threshold value, and performs the maximum discharge control when the oil temperature is less than the first threshold value. An engine hydraulic control device configured to perform. The engine hydraulic control device according to claim 2,
The controller is configured to perform the maximum discharge control when the valve stop mechanism is operated and the oil temperature detected by the oil temperature sensor is equal to or higher than a second threshold value set higher than the first threshold value. The hydraulic control device of the engine. The engine hydraulic control apparatus according to claim 3,
The controller controls the hydraulic pressure of the engine so that the second threshold value is set higher when the rotational speed of the engine is higher than when the rotational speed is low.

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