JP2015075053A - Internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an internal combustion engine which can suitably perform engine control according to the switching of use cams which is performed by a prescribed variable valve gear mechanism.SOLUTION: An internal combustion engine 50A comprises hydraulic connecting mechanisms 631, 632 which perform the connection and the release of the connection of two oscillating parts out of oscillating parts 63a, 63b and 63c by using a pin Pn11 and a pin Pn22, and also comprises a cam switch type variable valve gear mechanism 60A which selects a use cam for use in the drive of an intake valve 54, and an ECU 70A as a determination part for determining a switch state of the use cam on the basis of a change aspect of hydraulic pressure which changes according to the switch of the use cam. The ECU 70A determines the switch state of the use cam on the basis of, for example, a value of objective hydraulic pressure and a change width max-min. Actually, the value of the objective hydraulic pressure can be set at a maximum value max or a minimum value min.

Description

  The present invention relates to an internal combustion engine.

  A technique for determining a switching state of a cam used by a variable valve mechanism of a cam switching type is known. Patent Document 1 discloses a variable valve operating apparatus for an internal combustion engine that includes an operation determination unit that detects an operating oil pressure and determines an operation state of a variable valve lift mechanism based on the detected oil pressure. Japanese Patent Application Laid-Open No. H10-228561 discloses that the operating oil pressure is compared with a predetermined value to determine when the low-speed cam is used and when the high-speed cam is used.

JP-A-8-74537

  In recent years, a technique for determining the switching timing of a cam used by a variable valve mechanism with higher accuracy has been desired. However, for example, by comparing the hydraulic pressure with a predetermined value as in the technique disclosed in Patent Document 1, there is a possibility that the switching timing of the cam used cannot be determined with high accuracy. As a result, for example, there is a possibility that an abnormality in switching timing due to a sliding failure of the lock member cannot be grasped. Alternatively, comparing the operating oil pressure with a predetermined value requires a large number of oil pressure sensors in an internal combustion engine having a plurality of cylinders, which may be disadvantageous in terms of cost and mountability.

  In view of the above problems, an object of the present invention is to provide an internal combustion engine that can suitably determine a switching state of a use cam by a predetermined variable valve mechanism.

  The present invention relates to a plurality of cams used for driving a valve and a power transmitted to the valve from a camshaft provided with the plurality of cams while individually swinging according to a cam profile of the plurality of cams. A plurality of rocker arms configured to have a plurality of oscillating parts that mediate, and a plurality of hydraulic types that perform connection and disconnection of two oscillating parts among the plurality of oscillating parts by a lock member A switching mechanism, a variable valve mechanism of a cam switching type that selects a use cam that is a cam used for driving the valve from the plurality of cams, and a hydraulic pressure that changes according to the switching of the use cam. An internal combustion engine comprising: a determination unit that determines at least one of a state of the lock member and a switching state of the use cam according to the state of the lock member based on a change mode.

  The present invention provides the hydraulic pressure that changes according to the movement of the lock member in a connection mechanism in which the determination unit is connected or released when the use cam is switched among the plurality of connection mechanisms, and the valve is lifted. A configuration for determining completion of the operation of the locking member in a coupling mechanism that performs coupling or decoupling when the used cam is switched among the plurality of coupling mechanisms, based on the value and change range of the hydraulic pressure detected and stored during the period can do.

  In the present invention, the variable valve mechanism is provided with an oil passage that penetrates the plurality of swinging portions in a state where the valve is not lifted, and the determination portion reduces the hydraulic pressure transmitted by the oil passage. It can be set as the structure which determines the said use cam based on the fall aspect containing presence or absence.

  In the present invention, the variable valve mechanism is provided on at least one of the intake side and the exhaust side, and the rocker arm portion is provided for each cylinder of a plurality of cylinders, and at least one of the intake side and the exhaust side The rocker arm portion shares the oil passage between the plurality of cylinders, or the rocker arm portion shares the oil passage between the plurality of cylinders on the intake side and the exhaust side, and The variable valve mechanism may be configured to share the oil passage between the intake side and the exhaust side.

  In the present invention, the oil passage can also serve as a lubricating oil passage that supplies oil for lubrication.

  The present invention may be configured such that the oil passage is a different oil passage from an oil passage that supplies hydraulic pressure to the plurality of coupling mechanisms.

  According to the present invention, it is possible to suitably determine the use cam switching state by a predetermined variable valve mechanism.

1 is an overall configuration diagram of an internal combustion engine and its surroundings. It is a schematic block diagram of an internal combustion engine. It is a schematic block diagram of a variable valve mechanism. It is explanatory drawing of a connection mechanism. It is explanatory drawing of a cam switching state. It is explanatory drawing about determination. It is a figure which shows an example of 1st control with a flowchart. It is a figure which shows the unit of the variable valve mechanism of Example 2. FIG. It is explanatory drawing of the determination method of Example 2. FIG. It is a figure which shows an example of 2nd control with a flowchart. It is a 1st figure which shows the principal part of the other example of a variable valve mechanism. It is a 2nd figure which shows the principal part of the other example of a variable valve mechanism. It is a figure which shows the cam shaft of another example. It is explanatory drawing of the usage pattern of the usage cam of another example. It is explanatory drawing of the determination method in another example.

  Embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is an overall configuration diagram of the internal combustion engine 50A and its surroundings. FIG. 2 is a schematic configuration diagram of the internal combustion engine 50A. FIG. 3 is a schematic configuration diagram of the variable valve mechanism 60A. In FIG. 3, the variable valve mechanism 60A is shown together with the camshaft 65. The internal combustion engine 50A is a compression ignition type internal combustion engine, and has a plurality (four in this case) of cylinders 51a. The internal combustion engine 50A is mounted on a vehicle (not shown) together with the intake system 10, the exhaust system 20, and the exhaust gas recirculation system 40. The internal combustion engine 50A may be a spark ignition type internal combustion engine.

  The intake system 10 includes an air flow meter 11, an intercooler 12, and an intake manifold 13. The air flow meter 11 measures the amount of intake air. The intercooler 12 cools the intake air. The intake manifold 13 distributes intake air to each cylinder 51a of the internal combustion engine 50A.

  The exhaust system 20 includes an exhaust manifold 21 and a catalyst 22. The exhaust manifold 21 joins the exhaust from each cylinder 51a. The catalyst 22 purifies the exhaust. A supercharger 30 is provided in the intake system 10 and the exhaust system 20. The supercharger 30 supercharges intake air into the internal combustion engine 50A.

  The exhaust gas recirculation system 40 includes an EGR pipe 41, an EGR cooler 42, and an EGR valve 43. The EGR pipe 41 communicates the intake system 10 and the exhaust system 20. Specifically, the EGR pipe 41 communicates the passage assembly portion of the intake manifold 13 and the passage assembly portion of the exhaust manifold 21. The EGR cooler 42 cools the recirculated exhaust gas. The EGR valve 43 adjusts the amount of exhaust gas recirculated.

  The internal combustion engine 50A includes an ECU 70A, a cylinder block 51, a cylinder head 52, a piston 53, an intake valve 54, an exhaust valve 55, a fuel injection valve 56, a variable valve mechanism 60A, and a camshaft 65. I have. The piston 53, the intake valve 54, the exhaust valve 55, and the fuel injection valve 56 are provided for each cylinder 51a. A cylinder 51 a is formed in the cylinder block 51. A piston 53 is accommodated in the cylinder 51a. A cylinder head 52 is fixed to the upper surface of the cylinder block 51. The combustion chamber E is formed as a space surrounded by the cylinder block 51, the cylinder head 52 and the piston 53. The piston 53 is adjacent to the combustion chamber E.

  The cylinder head 52 is formed with an intake port 52 a that guides intake air to the combustion chamber E and an exhaust port 52 b that exhausts gas from the combustion chamber E. An intake valve 54 for opening and closing the intake port 52a and an exhaust valve 55 for opening and closing the exhaust port 52b are provided. Specifically, a plurality (two in this case) of the intake valves 54 and the exhaust valves 55 are provided for each cylinder 51a. The fuel injection valve 56 is provided in the cylinder head 52 and injects fuel into the combustion chamber E.

  The variable valve mechanism 60 </ b> A is provided in the cylinder head 52. The variable valve mechanism 60A is a cam-switching variable valve mechanism, and the intake valve 54 is selected from the cam Ca that is the first cam, the cam Cb that is the second cam, and the cam Cc that is the third cam. Select the cam to be used for driving. The cams Ca, Cb, and Cc are provided on the camshaft 65 and constitute a plurality (here, three) of cams that are used to drive the intake valve 54. The plurality of cams can be three or more cams.

  Specifically, the cams Ca, Cb, and Cc are provided corresponding to each of the plurality of cylinders 51a. Therefore, the cams Ca, Cb and Cc are specifically used for driving the intake valve 54 in each of the plurality of cylinders 51a. Specifically, the variable valve mechanism 60A selects the cam to be used for driving the intake valve 54 from the cams Ca, Cb and Cc in each of the plurality of cylinders 51a.

  The variable valve mechanism 60A includes a cam contact portion 61, a valve drive portion 62, a rocker arm portion 63, and a rocker arm shaft 64. The cam contact portion 61, the valve drive portion 62, and the rocker arm portion 63 are provided for each cylinder 51a and constitute a unit U.

  The cam contact portion 61 is a cam follower, and a plurality (three in this case) are provided in accordance with the cams Ca, Cb, and Cc. The cam contact portion 61 a indicates a cam contact portion that contacts the cam Ca among the plurality of cam contact portions 61. The cam contact portion 61b indicates the cam Cb, and the cam contact portion 61c indicates the cam contact portion that contacts the cam Cc. Each of the plurality of cam contact portions 61 is provided on the rocker arm portion 63.

  The valve drive unit 62 is provided on the rocker arm unit 63. A plurality of valve drive units 62 are provided in accordance with the number (here, two) of intake valves 54 provided for each cylinder 51 a, and transmit power to the intake valves 54. Specifically, for example, a screw tappet can be applied to the valve driving unit 62. The valve driving unit 62 may be a part of the rocker arm unit 63.

  The rocker arm portion 63 is a power mediation portion, and mediates the power transmitted from the camshaft 65 to the intake valve 54 together with the cam contact portion 61 and the valve drive portion 62. A rocker arm shaft 64 is inserted into the rocker arm portion 63. The rocker arm shaft 64 supports the rocker arm portion 63 so as to be swingable. The rocker arm shaft 64 is a common shaft for each unit U provided for each cylinder 51a. The rocker arm shaft 64 is provided along the extending direction of the camshaft 65.

  Specifically, the rocker arm portion 63 includes swinging portions 63a, 63b, and 63c that are a plurality of swinging portions. The swinging parts 63a, 63b, and 63c are arranged in the order of the swinging parts 63b, 63a, and 63c along the extending direction of the camshaft 65. The swing parts 63a, 63b and 63c individually swing according to the cam profiles of the cams Ca, Cb and Cc, and mediate the power transmitted from the cam shaft 65 to the intake valve 54.

  A cam contact portion 61a is provided on the swing portion 63a which is the first swing portion. For this reason, the swing part 63a swings according to the cam Ca. A cam contact portion 61b is provided on the swing portion 63b, which is the second swing portion, and a cam contact portion 61c is provided on the swing portion 63c, which is the third swing portion. For this reason, the swing part 63b swings according to the cam Cb, and the swing part 63c swings according to the cam Cc.

  The valve drive part 62 is provided in the swing part 63b and the swing part 63c. Therefore, in the rocker arm portion 63, specifically, the swinging portions 63b and 63c among the swinging portions 63a, 63b and 63c drive the intake valve 54. Each of the swinging parts 63a, 63b and 63c is supported by a rocker arm shaft 64 so as to be swingable individually.

  The rocker arm part 63 further includes connection mechanisms 631 and 632 which are a plurality of connection mechanisms. The connection mechanisms 631 and 632 are both hydraulic, and connect and release the two swinging parts among the swinging parts 63a, 63b, and 63c. Specifically, the connection mechanism 631 that is the first connection mechanism connects and disconnects the swing parts 63b and 63c, and the connection mechanism 632 that is the second connection mechanism connects the swing parts 63a and 63c. And disconnect. The connection mechanism 632 further connects and disconnects the swinging parts 63a and 63b.

  The swinging portion 63a is provided with a biasing member (for example, a return spring) that biases the cam contact portion 61a toward the cam Ca within a range in which the cam Ca can drive the intake valve 54. ing. For this reason, the cam contact portion 61a comes into contact with the cam Ca in the state where the swinging portion 63a is disconnected.

  FIG. 4 is an explanatory diagram of the coupling mechanisms 631 and 632. Specifically, the coupling mechanism 631 includes holding portions H11 and H12, pins Pn11 and Pn12, and a spring Sp1. The holding part H11 is provided in the swing part 63b, and the holding part H12 is provided in the swing part 63c. Each of the holding portions H11 and H12 is provided so as to be aligned along the extending direction of the camshaft 65 when the intake valve 54 is not lifted. Each of the holding portions H11 and H12 has a bottomed cylindrical shape and has the same inner diameter. The same thing includes a case where they are different from each other within a range of manufacturing error. The same applies to the following.

  The pin Pn11 is held by at least the holding part H11 among the holding parts H11 and H12. The pin Pn12 is held by the holding unit H12 among the holding units H11 and H12. Each of the pins Pn11 and Pn12 has a cylindrical shape, and has the same outer diameter. The outer diameter of each of the pins Pn11 and Pn12 is set smaller than the inner diameter of each of the holding portions H11 and H12 by the sliding clearance.

  A spring chamber G11 is formed between the bottom of the holding portion H11 and the pin Pn11. The spring chamber G11 is simultaneously a hydraulic chamber. A hydraulic chamber G12 is formed between the bottom of the holding portion H12 and the pin Pn12. The spring Sp1 is provided in the spring chamber G11. The spring Sp1 biases the pin Pn11.

An OCV (oil control valve) 81 is connected to the coupling mechanism 631. The OCV 81 is connected to the spring chamber G11 through the oil passage R11 and is connected to the hydraulic chamber G12 through the oil passage R12. OCV81 at the same time releasing the hydraulic pressure from the hydraulic chamber G12 when it is OFF, the convey hydraulic _{P in} the spring chamber G11. OCV81 at the same time to transmit the hydraulic pressure _{P in} the hydraulic chamber G12 if it is ON, the open hydraulic from the spring chamber G11. Hydraulic _{P in} is the oil pressure supplied to the common connection mechanism 631 and 632 on the connecting mechanism 631, 632 is transmitted to the connecting mechanism 631 and 632 via the OCV81,82. Hydraulic pressure P _in may be a hydraulic pressure in the main gallery.

When the OCV 81 is OFF, the connecting mechanism 631 connects the swinging parts 63b and 63c. In this case, specifically, in a state where the intake valve 54 is not lifted, the hydraulic pressure _{P in,} which is transmitted to the spring chamber G11 via a spring Sp1, and OCV81 is released from the hydraulic chamber G12 through OCV81 Accordingly, the pins Pn11 and Pn12 are moved together. As a result, the pin Pn11 is held by the holding portions H11 and H12, thereby connecting the swinging portions 63b and 63c. When OCV81 is OFF, the coupling mechanism 631 even when the hydraulic pressure _{P in} is not generated, by both moving the pin PN11, PN12 a spring Sp1, it is possible to perform the swinging portion 63 b, the coupling between 63c.

The connection mechanism 631 releases the connection between the swinging parts 63b and 63c when the OCV 81 is ON. Specifically in this case, in a state where the intake valve 54 is not lifted, is released from the spring chamber G11 hydraulic pressure _{P in} the transmitted to the hydraulic chamber G12 via a biasing force and OCV81 spring Sp1 through OCV81 The pins Pn11 and Pn12 are moved together against the hydraulic pressure. As a result, the pin Pn11 is held by the holding portion H11, so that the connection between the swinging portions 63b and 63c is released.

  Specifically, the coupling mechanism 632 includes holding portions H21, H22, and H23, pins Pn21, Pn22, and Pn23, and a spring Sp2. The holding part H21 is provided in the swinging part 63b, the holding part H22 is provided in the swinging part 63a, and the holding part H23 is provided in the swinging part 63c. Each of the holding portions H21, H22, and H23 is provided so as to be aligned along the extending direction of the camshaft 65 when the intake valve 54 is not lifted. The holding parts H21 and H23 have a bottomed cylindrical shape, and the holding part H22 has a cylindrical shape. The holding portions H21, H22, and H23 have the same inner diameter.

  The pin Pn21 is held by at least the holding part H21 among the holding parts H21 and H22. The pin Pn22 is held by at least the holding part H22 among the holding parts H22 and H23. The pin Pn23 is held by the holding unit H23. Each of the pins Pn21, Pn22, Pn23 has a cylindrical shape and has the same outer diameter. The outer diameters of the pins Pn21, Pn22, and Pn23 are set smaller than the inner diameters of the holding portions H21, H22, and H23 by the sliding clearance.

A hydraulic chamber G21 is formed between the bottom of the holding portion H21 and the pin Pn21. A spring chamber G22 is formed between the bottom of the holding portion H23 and the pin Pn23. The spring Sp2 is provided in the spring chamber G22. The spring Sp2 biases the pin Pn23. An OCV 82 is connected to the coupling mechanism 632. The OCV 82 is connected to the hydraulic chamber G21 via the oil passage R2. OCV82 the hydraulic _{P in} transmitted to the hydraulic chamber G21 if it is ON, the open hydraulic from hydraulic chamber G21 when is OFF.

The connection mechanism 632 performs connection between the swinging parts 63a and 63c when the OCV 82 is ON. In this case in particular, in a state where the intake valves 54 are not lifted, both pins PN21, PN22, PN23 pressure _{P in,} which is transmitted to the hydraulic chamber G21 through OCV82 is against the urging force of the spring Sp2 Move. As a result, the pin Pn22 is held by the holding portion H22 and the holding portion H23, thereby connecting the swinging portions 63a and 63c. The connection mechanism 632 also connects the swinging parts 63a and 63b when the OCV 82 is ON. The connection between the swinging parts 63a and 63b is performed by the pin Pn21 being held by the holding part H21 and the holding part H22.

  The connection mechanism 632 releases the connection between the swinging parts 63a and 63c when the OCV 82 is OFF. Specifically, in this case, when the intake valve 54 is not lifted, the spring Sp2 moves the pins Pn21, Pn22, and Pn23 against the hydraulic pressure released from the hydraulic chamber G21 via the OCV 82. As a result, the pin Pn21 is held by the holding portion H21 and the pin Pn22 is held by the holding portion H22, so that the connection between the swinging portions 63a and 63c is released. The connection mechanism 632 also releases the connection between the swinging parts 63a and 63b when the OCV 82 is OFF. The connection between the swinging parts 63a and 63b is released by the pin Pn21 being held by the holding part H21.

  In this way, specifically in the connection mechanism 631, the pin Pn11 connects and disconnects the swinging parts 63b and 63c. Further, in the connection mechanism 632, the pin Pn22 performs connection and release of the swinging parts 63a and 63c. Both pins Pn11 and Pn22 correspond to lock members. The pin Pn11 can be a first lock member, and the pin Pn22 can be a second lock member. In the connection mechanism 632, the pin Pn21 that connects and disconnects the swinging portions 63a and 63b may be used as a lock member instead of the pin Pn22. In the coupling mechanism 632, at least one of the pins Pn21 and Pn22 can be a lock member. Each of the oil passages R11, R12, R2 can be provided so as to be connected to a corresponding coupling mechanism among the coupling mechanisms 631, 632 via the rocker arm shaft 64.

  FIG. 5A to FIG. 5C are explanatory diagrams of the cam switching state. FIG. 5A shows a case where the cam Cb is used. FIG. 5B shows a case where the cams Cb and Cc are used cams. FIG.5 (c) shows the case where the cam Ca is used. 5A to 5C show the camshaft 65 and the lift curves La, Lb, and Lc together with the unit U. FIG. The lift curve La is a lift curve obtained when the intake valve 54 is driven according to the cam profile of the cam Ca. The lift curve Lb is a lift curve obtained when the intake valve 54 is driven according to the cam profile of the cam Cb, and the lift curve Lc is a lift curve obtained when the intake valve 54 is driven according to the cam profile of the cam Cc.

  As shown in FIG. 5A, in the variable valve mechanism 60A, the connecting mechanism 631 connects the swinging parts 63b and 63c, and the connecting mechanism 632 releases the connection between the swinging parts 63a and 63c, and the swinging part. The cam Cb can be used as a use cam in a state in which the connection of 63a and 63b is released. Further, as shown in FIG. 5B, the connection mechanism 631 releases the connection of the swing parts 63b and 63c, and the connection mechanism 632 releases the connection of the swing parts 63a and 63c, and the swing parts 63a and 63b. The cams Cb and Cc can be used cams in a state where the connection is released. Further, as shown in FIG. 5C, the connecting mechanism 631 connects the swing parts 63b and 63c, and the connection mechanism 632 connects the swing parts 63a and 63c and the swing parts 63a and 63b. In this state, the cam Ca can be used as a use cam.

  The cams Ca, Cb, Cc are arranged in the order of the cams Cb, Ca, Cc along the extending direction of the camshaft 65. Cams Ca, Cb and Cc have different cam profiles. As indicated by the lift curves La, Lb, and Lc, the cam profiles of the cams Ca, Cb, and Cc are such that the cam Ca has a larger lift amount than the cam Cb, and the cam Cb has a larger lift amount than the cam Cc. Is set. In other words, the cam profiles of the cams Ca, Cb, and Cc are set so that the lift curve Lb is included in the lift curve La and the lift curve Lc is included in the lift curve Lb.

  The variable valve mechanism 60A has a plurality of modes as cam switching modes. The cam switching mode is distinguished for each use cam switching mode. The usage cam switching mode can be specified by switching from one usage pattern to the other usage pattern between any two usage patterns among a plurality of usage patterns of usage cams. Specifically, the usage pattern of the usage cam includes a first pattern in which the usage cam is the cam Cb, a second pattern in which the usage cam is the cams Cb and Cc, and a third pattern in which the usage cam is the cam Ca. There are a total of three patterns.

  Specifically, the cam switching mode includes the following first to third modes. The first mode is a case where the use cam is switched from the cam Cb to the cams Cb and Cc. The second mode is a case where the use cam is switched from the cam Cb to the cam Ca. The third mode is a case where the use cam is switched from the cams Cb and Cc to the cam Ca. Specifically, the plurality of modes that the variable valve mechanism 60A has as the cam switching mode are here the first to third modes, and the switching mode of the cam used is the reverse of the first to third modes. There are six modes in total, each of the fourth to sixth modes.

  The ECU 70A shown in FIG. 1 and the like is an electronic control device, and an EGR valve 43, a fuel injection valve 56, and OCVs 81 and 82 are electrically connected as control objects to the ECU 70A. The air flow meter 11, the crank angle sensor 91 for detecting the crank angle θ, the accelerator opening sensor 92 for making an acceleration request to the internal combustion engine 50A, and the hydraulic sensors 93 and 94 for detecting the hydraulic pressures P1 and P2 are sensors. -Electrically connected as switches. The hydraulic pressure P1 is the hydraulic pressure in the spring chamber G11, and the hydraulic pressure P2 is the hydraulic pressure in the hydraulic chamber G21. The oil pressure P1 can be detected from the spring chamber G11, and the oil pressure P2 can be detected from the oil pressure chamber G21 via an oil passage for detecting oil pressure. Based on the output of the crank angle sensor 91, the ECU 70A detects the engine speed NE, which is the engine speed.

  In the ECU 70A, for example, the following determination unit and determination unit are realized by executing processing while using the temporary storage area of the RAM as necessary based on a program stored in the ROM. These configurations may be realized in, for example, a plurality of electronic control devices.

  The determination unit determines the state of a pin (specifically, at least one of the pins Pn11 and Pn22 here) as a lock member based on the change of the hydraulic pressure that changes according to the switching of the use cam. Specifically, the determination unit changes according to the movement of the pin as the lock member while the intake valve 54 is not lifted in the connection mechanism 631, 632 that connects or releases the connection when the use cam is switched. The state of the pin as the lock member is determined based on the hydraulic pressure to be applied (hereinafter referred to as the target hydraulic pressure). The target hydraulic pressure is a hydraulic pressure used for determination, and specifically, here is at least one of the hydraulic pressures P1 and P2.

  The determining unit determines the target hydraulic pressure for at least one of the hydraulic pressures P1 and P2 based on the cam switching mode. The target hydraulic pressure can be specified in advance as at least one of the hydraulic pressures P1 and P2 according to the cam switching mode. The target hydraulic pressure is the hydraulic pressure detected along with the time factor. Specifically, the target hydraulic pressure can be, for example, a hydraulic pressure obtained according to the crank angle θ.

  Specifically, the determination unit determines the state of the pin Pn11 based on the hydraulic pressure P1 when the target hydraulic pressure is the hydraulic pressure P1. Further, when the target hydraulic pressure is the hydraulic pressure P2, the state of the pin Pn22 is determined based on the hydraulic pressure P2. Further, when the target hydraulic pressure is the hydraulic pressure P1 or P2, the state of the pins Pn11 and Pn21 is determined.

  Specifically, the determination unit performs a first determination to determine whether or not the target pin has operated (more specifically, whether or not the operation has started). The target pin is a pin as a lock member in the coupling mechanism that performs coupling or decoupling when the use cam is switched among the coupling mechanisms 631 and 632, and specifically, is at least one of the pins Pn11 and Pn22. Further, the determination unit performs a second determination for determining whether or not the switching of the use cam is completed. In performing the second determination, the determination unit specifically determines the completion of the operation of the target pin based on the value and change range of the target hydraulic pressure detected and stored while the intake valve 54 is not lifted.

  FIG. 6 is an explanatory diagram of determination. FIG. 6 shows an example of the change in the target hydraulic pressure when the use cam is switched, together with the lift amount of the intake valve 54 and ON / OFF of the OCV 81. In FIG. 6, the target hydraulic pressure and the ON / OFF of the OCV 81 are indicated by a solid line, and the lift amount of the intake valve 54 is indicated by a broken line. FIG. 6 shows a case where the cam switching mode is the fourth mode (that is, the usage cam switching mode is switching from the cams Cb and Cc to the cam Cb) and the target hydraulic pressure is the hydraulic pressure P1. FIG. 6 also shows a hydraulic pressure P1 ′ that is the hydraulic pressure of the hydraulic chamber G12. The predetermined value α1 is a value for detecting the start of change in the target hydraulic pressure in accordance with the switching of the use cam.

  Regarding the first determination, in this example, the determination unit specifically has the difference between the initial value ini and the minimum value min in the target hydraulic pressure detected and stored while the intake valve 54 is not lifted. When the target value is larger than the predetermined value α3, it is determined that the target pin is activated. Specifically, the period when the intake valve 54 is not lifted is a base circle section, and the base circle section is a section where the base circle portion of the use cam determines the lift amount of the intake valve 54. The predetermined value α3 is a value for detecting a pressure change (specifically, a pressure drop in this example) generated by the start of movement of the target pin.

  Thus, the determination part which performs 1st determination is a change mode of the oil pressure which changes according to switching of a use cam, Comprising: Whether the object pin act | operated based on the change aspect at the time of the action | operation start of an object pin Determine. The determination unit further determines whether or not the target pin is locked by determining whether or not the target pin has been operated until a predetermined time elapses. The predetermined time may be, for example, a use cam switching completion allowable time in a normal state.

  Regarding the second determination, in this example, the determination unit specifically operates the operation of the target pin based on the minimum value min and the change width max-min of the target hydraulic pressure detected and stored while the intake valve 54 is not lifted. It is determined whether or not is completed. Then, when the minimum value min is larger than the predetermined value α2 and the change width max-min is smaller than the predetermined value β, it is determined that the operation of the target pin is completed.

  The change width max-min is the magnitude of the difference between the maximum value max and the minimum value min of the target hydraulic pressure. The predetermined value β is a value for determining whether or not the fluctuation of the target hydraulic pressure has converged. The predetermined value α2 is set to a value at which the target hydraulic pressure does not pass after the operation of the target pin is completed. Thus, the determination part which performs 2nd determination determines completion | finish of operation | movement of an object pin based on the convergence aspect of the hydraulic pressure which changes according to switching of a use cam. In performing the second determination, the target hydraulic pressure can be stored for each base circle section.

Specific values of the predetermined values α1, α2, α3, and β may be different from each other, for example, when the target hydraulic pressure is the hydraulic pressure P1 and when the target hydraulic pressure P is the hydraulic pressure P2. The predetermined value [alpha] 1, [alpha] 2, .alpha.3, specific values of β may be changed according to the hydraulic pressure P _in, for example.

  The target hydraulic pressure may be the hydraulic pressure P1 ′ that is the back pressure in this example instead of the hydraulic pressure P1 that is the supply pressure in this example. In this case, for example, when the cam switching mode is the fourth mode, the determination unit sets the initial value ini and the maximum value max in the hydraulic pressure P1 ′ detected and stored while the intake valve 54 is not lifted. When the magnitude of the difference is larger than the predetermined value α3 ′, it can be determined that the target pin has been activated. Further, when the maximum value max is smaller than the predetermined value α2 ′ and the change width max-min is smaller than the predetermined value β ′, it can be determined that the operation of the target pin is completed.

  The predetermined values α1 ′, α2 ′, α3 ′, and β ′ can be set in the same manner as the predetermined values α1, α2, α3 ′, and β. The maximum value max corresponds to the value of the target hydraulic pressure when the hydraulic pressure P1 ′ is the target hydraulic pressure. Therefore, specifically, the value of the target hydraulic pressure can be a minimum value min when the target hydraulic pressure is a supply pressure, and a maximum value max when the target hydraulic pressure is a back pressure. The determination unit can determine the state of the pin as the lock member when there is a request to switch the use cam.

  Next, an example of first control that is control performed by the ECU 70A will be described with reference to a flowchart shown in FIG. FIG. 7 shows a case where the switching of the use cam is started in the fourth mode. This flowchart can be started when there is a use cam switching request. The ECU 70A detects the hydraulic pressure P1 (step S1), and determines whether or not the detected hydraulic pressure P1 exceeds a predetermined value α1 (step S2).

  If a negative determination is made in step S2, the ECU 70A turns on the timer (step S3) and determines whether or not a predetermined time has elapsed (step S4). And if it is negative determination, it will return to step S1, and if it is affirmation determination, it will determine with OCV81 having abnormality (step S5). After step S5, the process returns to step S1. After step S5, this flowchart may be terminated.

  If an affirmative determination is made in step S2, ECU 70A determines whether or not it is a base circle section (step S11). If an affirmative determination is made in step S11, the ECU 70A stores the hydraulic pressure P1 [i] (step S12). The oil pressure P1 [i] indicates the oil pressure P1 in the i-th base circle section. The number i is a number updated every time the base circle section becomes a new base circle section, and the initial value is 1. After step S12, the process returns to step S1. In this case, in the subsequent routine, the hydraulic pressure P1 [i] is stored in step S12 until a negative determination is made in step S11.

  If a negative determination is made in step S11, the ECU 70A determines whether or not the flag F is OFF (step S21). The flag F is a flag indicating that it is determined that the target pin has been activated. If the determination is affirmative, the ECU 70A determines whether or not the magnitude of the difference between the initial value ini and the minimum value min is greater than a predetermined value α3 in the stored hydraulic pressure P1 [i] (step S22). If the determination is affirmative, the ECU 70A determines that the target pin has been operated, and turns on the flag F (step S23). After step S23, the stored hydraulic pressure P1 [i] is cleared (step S29), and the process returns to step S1.

  If a negative determination is made in step 22, the ECU 70A determines whether or not a predetermined time has elapsed (step S24). Whether or not the predetermined time has elapsed can be determined by whether or not the number i is larger than a predetermined number, for example. The predetermined number may be set according to the engine operating state, for example. If an affirmative determination is made in step S24, the ECU 70A determines that the target pin is locked (step S25). After step S25, the process returns to step S1. This flowchart may be terminated after step S25. If a negative determination is made in step S24, the process proceeds to step S29.

  If a negative determination is made in step S21, the ECU 70A determines whether or not the change width max-min is smaller than the predetermined value β at the stored hydraulic pressure P1 [i] (step S26). Further, following the affirmative determination in step S21, it is determined whether or not the minimum value min is larger than the predetermined value α2 at the stored hydraulic pressure P1 [i] (step S27). If a negative determination is made in step S26 or S27, the process proceeds to step S29.

  If an affirmative determination is made in steps S26 and S27, ECU 70A determines that the operation of the target pin has been completed (step S28). After step S28, the process returns to step S1. This flowchart may be terminated after step S28.

  Next, main effects of the internal combustion engine 50A will be described. The internal combustion engine 50A determines the state of the pin as the lock member based on the change of the hydraulic pressure that changes in accordance with the switching of the use cam, thereby determining the switching state of the use cam by the variable valve mechanism 60A. Can be suitably determined. Specifically, the internal combustion engine 50A determines whether the operation of the target pin is completed based on the value of the target hydraulic pressure detected and stored while the intake valve 54 is not lifted and the change width max-min. Can be suitably determined in terms of timing.

  The internal combustion engine 50A is a change mode of the hydraulic pressure that changes according to the switching of the use cam, and based on the change mode at the start of the operation of the target pin, it is determined whether or not the target pin has been operated. The operation start timing can also be determined. Further, it can be determined whether or not the target pin is locked by determining whether or not the target pin has been operated before the predetermined time elapses.

  Specifically, in the internal combustion engine 50A, in the target hydraulic pressure detected and stored while the intake valve 54 is not lifted, the difference between the initial value ini and the minimum value min when the target hydraulic pressure is the supply pressure. Is larger than the predetermined value α3, and if the target hydraulic pressure is a back pressure, the target pin is actuated when the difference between the initial value ini and the maximum value max is larger than the predetermined value α3 ′. By determining, it can be determined whether or not the target pin is activated.

  The internal combustion engine according to the present embodiment is substantially the same as the internal combustion engine 50A shown in FIG. 2 except for the following points. The internal combustion engine according to the second embodiment has another variable valve mechanism in place of the variable valve mechanism 60A in FIG. 2 (hereinafter referred to as a variable valve mechanism 60B), and another ECU is used instead of the ECU 70A. (Hereinafter referred to as ECU 70B). Further, the internal combustion engine according to the second embodiment has another hydraulic sensor (hereinafter referred to as a hydraulic sensor 95) instead of the hydraulic sensors 93 and 94 shown in FIG. Hereinafter, the internal combustion engine of the second embodiment configured as described above is referred to as an internal combustion engine 50B.

  The variable valve mechanism 60B is substantially the same as the variable valve mechanism 60A except that a unit U ′ described later is provided instead of the unit U. In the ECU 70B, a determination unit to be described later is realized instead of the determination unit described in the first embodiment, a determination unit is not realized, and a hydraulic sensor 95 is used as a sensor switch instead of the hydraulic sensors 93 and 94. The ECU 70A is substantially the same as the ECU 70A except that it is connected. It should be noted that by further modifying the internal combustion engine 50A, it is possible to further add the constituent requirements of the internal combustion engine 50B to the internal combustion engine 50A.

  FIG. 8 is a diagram showing the unit U ′. The unit U ′ is substantially the same as the unit U except that an oil passage R3 which is an oil passage different from the oil passages R11, R12 and R2 for supplying hydraulic pressure to the coupling mechanisms 631 and 632 is further provided. Here, the difference in the rocker arm portion 63 depending on the presence or absence of the oil passage R3 is not particularly distinguished by a symbol. In FIG. 8, the oil passages R11, R12 and R2 are not shown. The oil passage R3 is provided so as to penetrate the swinging parts 63a, 63b, 63c in a state where the intake valve 54 is not lifted. The oil passage R3 is shared by the rocker arm portion 63 among the plurality of cylinders 51 on the intake side. The oil passage R3 also serves as a lubricating oil passage that supplies oil for lubrication. Specifically, the lubricating oil passage is an oil passage for supplying oil to the lash adjuster, and in the variable valve mechanism 60B, the valve drive unit 62 is specifically a lash adjuster.

  A hydraulic pressure sensor 95 is provided in the oil passage R3. Specifically, the hydraulic sensor 95 is provided in a portion of the oil passage R3 on the downstream side of the plurality of swinging portions 63a, 63b, and 63c. For this reason, the hydraulic sensor 95 detects the hydraulic pressure P3 transmitted by the oil passage R3. Specifically, the hydraulic pressure P3 is a hydraulic pressure transmitted from the plurality of swinging parts 63a, 63b and 63c through the oil passage R3. The ECU 70B implements a determination unit that determines the switching state of the use cam based on the hydraulic pressure P3.

  FIG. 9A to FIG. 9D are explanatory diagrams of a determination method based on the hydraulic pressure P3. FIG. 9A shows a change in the hydraulic pressure P3 when the cam used is the cam Ca. FIG. 9B shows a change in the hydraulic pressure P3 when the cam used is the cam Cb. FIG. 9C shows the change in the hydraulic pressure P3 when the cams used are cams Cb and Cc. FIG. 9D shows lift curves La, Lb, and Lc. 9 (a) to 9 (d), the horizontal axis has a common crank angle.

  When the cam used is the cam Ca, the connecting mechanism 631 connects the swinging parts 63b and 63c with the pin Pn11, and the connecting mechanism 632 connects the swinging parts 63a and 63c with the pin Pn22. For this reason, in this case, the swinging parts 63a, 63b, and 63c integrally swing according to the cam Ca. As a result, the hydraulic pressure P3 does not change as shown in FIG.

  When the cam used is the cam Cb, the connecting mechanism 631 connects the swinging parts 63b and 63c with the pin Pn11, and the connecting mechanism 632 disconnects the swinging parts 63a and 63c with the pin Pn22. For this reason, in this case, the swinging parts 63b and 63c integrally swing according to the cam Cb, while the swinging part 63a swings according to the cam Ca. In this case, the oil passage R3 is blocked by the occurrence of a shift between the swinging part 63a and the swinging parts 63b and 63c in the swinging direction. As a result, as shown in FIG. 9B, the hydraulic pressure P3 decreases while a deviation occurs between the swinging part 63a and the swinging parts 63b and 63c in the swinging direction.

  When the cams used are cams Cb and Cc, the connecting mechanism 631 uses the pin Pn11 to disconnect the swinging parts 63b and 63c, and the connecting mechanism 632 uses the pin Pn22 to disconnect the swinging parts 63a and 63c. . Therefore, in this case, the swinging part 63a swings in response to the cam Ca, the swinging part 63b swings in response to the cam Cb, and the swinging part 63c swings in response to the cam Cc. In this case, the oil path R3 is blocked due to a deviation between the rocking parts 63a and 63b in the rocking direction, and the oil path R3 is blocked due to a deviation between the rocking parts 63a and 63c. The As a result, as shown in FIG. 9C, the hydraulic pressure P3 is lowered while there is a deviation between the swinging parts 63a and 63b and between the swinging parts 63a and 63c.

  For this reason, the determination part determines the switching state of the use cam according to the state of the pin as a locking member specifically based on the fall aspect including the presence or absence of fall of the hydraulic pressure P3. The decrease mode is, for example, a decrease period. For example, the decrease mode may be at least one of a decrease period, a decrease timing, and a recovery timing of the hydraulic pressure P3. In determining the use cam switching state in this manner, the determination unit specifically determines which of the cams Ca, Cb, and Cc is the use cam. Specifically, the determination unit determines the use cam as the use cam switching state.

  Next, an example of the second control, which is the control performed by the ECU 70B, will be described using the flowchart shown in FIG. The ECU 70B detects the hydraulic pressure P3 (step S21) and determines whether or not the detected hydraulic pressure P3 has decreased (step S22). If it is affirmation determination, ECU70B will start the measurement of the fall period of the hydraulic pressure P3 (step S23). Subsequently, the ECU 70B determines whether or not the hydraulic pressure P3 has been recovered (step S24). If a negative determination is made, the process returns to step S24.

  If the determination in step S24 is affirmative, the ECU 70B ends the measurement of the decrease period of the hydraulic pressure P3 (step S25), and the decrease period of the hydraulic pressure P3 is a predetermined period (here, the decrease in the hydraulic pressure P3 when the cam used is the cam Cb). Period) is determined (step S26). If the determination is affirmative, the ECU 70B determines that the cam used is the cam Cb (step S28). If the determination is negative, the ECU 70B determines that the cams used are the cams Cb and Cc (step S29). After steps S28 and S29, the process returns to step S21.

  If a negative determination is made in step S22, the ECU 70B determines whether or not there is no decrease in the hydraulic pressure P3 during one combustion cycle (step S27). If a negative determination is made, the process returns to step S21. If the determination is affirmative, the ECU 70B determines that the use cam is the cam Ca (step S30). After step S30, the process returns to step S21.

  Next, main effects of the internal combustion engine 50B will be described. The internal combustion engine 50B determines the use cam as the use cam switching state based on a reduction mode including the presence or absence of a decrease in the hydraulic pressure P3. In this case, the internal combustion engine 50B can determine the use cam switching state by providing the oil pressure sensor 95 in the oil passage R3. For this reason, the internal combustion engine 50B can suitably determine the switching state of the use cam in terms of cost and mountability.

  Specifically, the internal combustion engine 50B has a configuration in which the rocker arm portion 63 shares the oil path R3 among the plurality of cylinders 51 on the intake side, so that one hydraulic sensor 95 can determine the cam used for each cylinder 51. In other words, the internal combustion engine 50B can be specifically configured to determine the switching state of the use cam in terms of cost and mountability.

  The internal combustion engine 50B has a configuration in which the oil passage R3 also serves as a lubrication system oil passage for supplying oil for lubrication, so that an increase in size of the rocker arm portion 63 for securing the oil passage can be prevented or suppressed. If the oil passage R3 also serves as a lubricating oil passage, if the oil passage is a lubricating oil passage, the oil supply is intermittently supplied by shutting off the oil passage R3 according to the swinging of the swinging portions 63a to 63c. Is also suitable in that there is no particular hindrance.

  Although the embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and changes can be made within the scope of the gist of the present invention described in the claims. It can be changed.

  For example, in the above-described embodiment, the case where the valve is the intake valve 54 has been described. However, the present invention is not necessarily limited to this, and the valve may be, for example, an exhaust valve. Further, the variable valve mechanism may be provided on each of the intake side and the exhaust side, for example. In this case, the rocker arm portion shares an oil passage corresponding to the oil passage R3 among the plurality of cylinders on the intake side and the exhaust side, and the variable valve mechanism is an oil passage equivalent to the oil passage R3 between the intake side and the exhaust side. By sharing this, it is possible to share the hydraulic pressure sensor between the intake side and the exhaust side. As a result, it can also be set as the structure advantageous in terms of cost. The variable valve mechanism when the valve is an exhaust valve is, for example, as follows.

  FIG. 11 is a first view showing a main part of a variable valve mechanism 60 ′ which is another example of the variable valve mechanism. FIG. 12 is a second view showing the main part of the variable valve mechanism 60 ′. FIGS. 13A and 13B are views showing the camshaft 65 ′. FIG. 13A is an overall view of the camshaft 65 ′, and FIG. 13B is a view of the cams Ca ′, Cb ′, and Cc ′ in the AA cross section shown in FIG. FIG. 11 shows the variable valve mechanism 60 ′ together with the camshaft 65 ′. FIG. 12 shows a variable valve mechanism 60 ′ together with OCVs 81 ′ and 82 ′.

  The variable valve mechanism 60 ′ selects a cam to be used for driving the exhaust valve 55 from among the cam Ca ′, the cam Cb ′, and the cam Cc ′. Cams Ca ′, Cb ′ and Cc ′ are provided on the camshaft 65 ′. The cams Ca ′, Cb ′ and Cc ′ constitute a plurality of (three in this case) cams used for driving the exhaust valve 55. Cams Ca ′, Cb ′ and Cc ′ are arranged in this order.

  The cams Ca ′, Cb ′ and Cc ′ have different cam profiles. Each of the cam profiles of the cams Ca ′ and Cb ′ is set to drive the exhaust valve 55 in at least the exhaust stroke (exhaust stroke here) of the exhaust stroke and the intake stroke. Specifically, the cam profiles of the cams Ca ′ and Cb ′ include the valve opening period of the exhaust valve 55 corresponding to the cam Cb ′ within the valve opening period of the exhaust valve 55 corresponding to the cam Ca ′, and the cam Ca ′. This is set so that the lift amount of the exhaust valve 55 is larger than that of the cam Cb ′.

  The cam profile of the cam Cc ′ is set to drive the exhaust valve 55 at a timing different from that of the cam Ca ′ or the cam Cb ′. Specifically, the cam profile of the cam Cc ′ is set so that the exhaust valve 55 opens during the opening period of the intake valve 54. The cam Cc ′ is a cam used together with the cam Cb ′. The cam Cc ′ is a cam that can be used together with the cam Ca ′.

  The variable valve mechanism 60 ′ includes a rocker arm 63 ′ and hydraulic coupling mechanisms 631 ′ and 632 ′. The rocker arm 63 'swings individually according to the cam profiles of the cams Ca', Cb 'and Cc', and swings 63a 'and 63b that mediate the power transmitted from the camshaft 65' to the exhaust valve 55. 'And 63c'.

  The swing part 63a ′ is provided with a cam contact part 61a ′, the swing part 63b ′ is provided with a cam contact part 61b ′, and the swing part 63c ′ is provided with a cam contact part 61c ′. Cam contact part 61a 'shows the cam contact part contact | abutted to cam Ca' among several cam contact parts 61 '. The cam contact portion 61b 'indicates the cam Cb', and the cam contact portion 61c 'indicates the cam contact portion that contacts the cam Cc'.

The connection mechanisms 631 ′ and 632 ′ perform connection and disconnection by the same mechanism as the connection mechanisms 631 and 632. For this reason, description is abbreviate | omitted about the specific structure of connection mechanism 631 ', 632'. An OCV 81 ′ is connected to the coupling mechanism 631 ′, and an OCV 82 ′ is connected to the coupling mechanism 632 ′. OCV81' the hydraulic _{P in} is transmitted to the coupling mechanism 631' If it is ON, the open hydraulic from coupling mechanism 631' when is OFF. OCV82' the hydraulic _{P in} is transmitted to the coupling mechanism 632' If it is ON, the open hydraulic from coupling mechanism 632' when is OFF.

When the OCV 81 ′ is ON, the connection mechanism 631 ′ connects the swinging parts 63a ′ and 63b ′. In this case, specifically, in a state where the exhaust valve 55 does not lift pins Pn11', to both move the Pn12' pressure _{P in} transmitted through the OCV81' against the biasing force of the spring Sp1' . As a result, the pin Pn11 ′ is held by the holding portion H11 ′ and the holding portion H12 ′, thereby connecting the swinging portions 63a ′ and 63b ′.

  When the OCV 81 ′ is OFF, the connection mechanism 631 ′ releases the connection between the swinging parts 63a ′ and 63b ′. Specifically, in this case, in a state where the exhaust valve 55 is not lifted, the springs Sp1 ′ move both the pins Pn11 ′ and Pn12 ′ against the hydraulic pressure released via the OCV 81 ′. As a result, the pin Pn11 ′ is held by the holding portion H11 ′, so that the connection between the swinging portions 63a ′ and 63b ′ is released. For this reason, the connection mechanism 631 ′ performs connection and release of the swinging parts 63a ′ and 63b ′ by the pin Pn11 ′.

  Similarly to the connection mechanism 631 ′, the connection mechanism 632 ′ performs connection and release of the swinging parts 63b ′ and 63c ′ by the pin Pn21 ′. For this reason, the connecting mechanisms 631 ′ and 632 ′ perform connection and release of connection between the two swinging parts among the swinging parts 63a ′, 63b ′, and 63c ′ by the pin Pn11 ′ and the pin Pn21 ′.

  In the variable valve mechanism 60 ′, each valve drive unit 62 ′ is provided on the swinging unit 63b ′. Therefore, in the variable valve mechanism 60 ′, the swinging portion 63b ′ of the swinging portions 63a ′, 63b ′, and 63c ′ drives the exhaust valve 55. The usage pattern of the usage cam realized by the variable valve mechanism 60 ′ is as follows.

  FIG. 14A to FIG. 14C are explanatory diagrams of usage patterns of usage cams. 14A shows the first pattern, FIG. 14B shows the second pattern, and FIG. 14C shows the third pattern. The oscillating part 63a ′ and the oscillating part 63c ′ indicated by broken lines indicate that the connection is released.

  The first pattern is when the cam used is the cam Ca ′. In this case, the connecting mechanism 631 ′ connects the swinging parts 63a ′ and 63b ′, and the connecting mechanism 632 ′ releases the connection between the swinging parts 63b ′ and 63c ′. In this case, the exhaust valve 55 can be driven according to the cams Ca ′ and Cb ′ in terms of the connection mode. On the other hand, as described above, the cam profiles of the cams Ca ′ and Cb ′ are set such that the lift amount of the exhaust valve 55 is larger in the cam Ca ′ than in the cam Cb ′ in each phase. Therefore, in this case, the exhaust valve 55 is driven according to the cam Ca ′.

  The second pattern is a case where the cam used is the cam Cb ′. In this case, the connection mechanism 631 ′ releases the connection between the swinging parts 63a ′ and 63b ′, and the connection mechanism 632 ′ releases the connection between the swinging parts 63b ′ and 63c ′. In this case, power is not transmitted from the swing part 63a ′ to the swing part 63b ′. Similarly, no power is transmitted from the swinging part 63c ′ to the swinging part 63b ′. Therefore, in this case, the exhaust valve 55 is driven according to the cam Cb ′.

  The third pattern is a case where the cams used are cams Cb ′ and Cc ′. In this case, the connection mechanism 631 ′ releases the connection between the swinging parts 63a ′ and 63b ′, and the connection mechanism 632 ′ performs the connection between the swinging parts 63b ′ and 63c ′. As a result, the exhaust valve 55 is driven according to the cams Cb ′ and Cc ′.

  FIG. 15 is an explanatory diagram of a determination method based on the hydraulic pressure P3 in the variable valve mechanism 60 ′. FIG. 15A shows a change in the hydraulic pressure P3 when the cam used is the cam Ca ′. FIG. 15B shows a change in the hydraulic pressure P3 when the cam used is the cam Cb ′. FIG. 15C shows changes in the hydraulic pressure P3 when the cams used are cams Cb ′ and Cc ′. FIG. 15D shows lift curves La ′, Lb ′, and Lc ′ of the intake valve 54 corresponding to the cams Ca ′, Cb ′, and Cc ′. In FIG. 15 (a) to FIG. 15 (d), the crank angle on the horizontal axis is common.

  Here, in the variable valve mechanism 60 ′, the oil passage R3 is provided as follows from the viewpoint of improving the determination accuracy. That is, the hydraulic pressure P3 is provided between the swinging portions 63b ′ and 63c ′ so as to decrease with a larger shift than between the swinging portions 63a ′ and 63b ′. For this reason, when the deviation occurs between the swinging parts 63a ′ and 63b ′, the decrease period of the hydraulic pressure P3 is longer than when the deviation occurs between the swinging parts 63b ′ and 63c ′.

  When the cam used is the cam Ca ′, the connecting mechanism 631 ′ connects the swinging parts 63a ′ and 63b ′, and the connecting mechanism 632 ′ disconnects the swinging parts 63b ′ and 63c ′. Therefore, in this case, the swinging parts 63a ′ and 63b ′ are integrally swung according to the cam Ca ′, while the swinging part 63c ′ is swung according to the cam Cc ′. In this case, the oil passage R3 is blocked by the occurrence of a shift between the swinging parts 63a ′ and 63b ′ and the swinging part 63c ′ in the swinging direction. As a result, as shown in FIG. 15 (a), the hydraulic pressure P3 decreases while there is a deviation between the swinging parts 63b ′ and 63c ′ in the swinging direction.

  When the cam used is the cam Cb ′, the connecting mechanism 631 ′ disconnects the swinging parts 63a ′ and 63b ′, and the connecting mechanism 632 ′ disconnects the swinging parts 63b ′ and 63c ′. Therefore, in this case, the swinging part 63a ′ swings according to the cam Ca ′, the swinging part 63b ′ swings according to the cam Cb ′, and the swinging part 63c ′ swings according to the cam Cc ′. In this case, the oil path R3 is blocked by a deviation between the rocking parts 63a ′ and 63b ′ in the rocking direction, and the oil path R3 is caused by a deviation between the rocking parts 63b ′ and 63c ′. Blocked. As a result, as shown in FIG. 15 (b), the hydraulic pressure P3 is lowered while there is a deviation between the swinging parts 63a ′ and 63b ′ and between the swinging parts 63b ′ and 63c ′.

  When the cams used are cams Cb ′ and Cc ′, the connecting mechanism 631 ′ disconnects the swinging parts 63a ′ and 63b ′, and the connecting mechanism 632 ′ connects the swinging parts 63b ′ and 63c ′. . Therefore, in this case, the swinging part 63a ′ swings according to the cam Ca ′, while the swinging parts 63b ′ and 63c ′ swing as a unit according to the cams Cb ′ and Cc ′. In this case, the oil passage R3 is blocked due to a shift between the swinging parts 63a ′ and 63b ′ in the swinging direction. As a result, as shown in FIG. 15 (c), the hydraulic pressure P3 decreases while the displacement between the swinging parts 63a ′ and 63b ′ occurs.

  As shown in FIG. 15 (a) to FIG. 15 (c), the reduction mode of the hydraulic pressure P3 varies depending on the cam used even in this case. For this reason, even in this case, the determination unit can determine the switching state of the use cam (specifically, the use cam) based on the decrease mode of the hydraulic pressure P3. Here, the case where the cams used are cams Ca ′ and Cc ′ is excluded from the usage pattern of the cams used. However, in this case, the cams used are cam Ca ′ because the hydraulic pressure P3 does not decrease. , Cc ′.

Internal combustion engine 50A, 50B
Intake valve 54
Variable valve mechanism 60A, 60B, 60 '
Connecting mechanism (first connecting mechanism) 631, 631 ′
Connection mechanism (second connection mechanism) 632, 632 ′
Camshaft 65, 65 '
ECU 70A, 70B

Claims (6)

Multiple cams used to drive the valve;
The plurality of cams individually swing according to the cam profiles of the plurality of cams, and have a plurality of swinging portions that mediate power transmitted from the camshafts provided with the plurality of cams to the valves. A rocker arm portion, and a plurality of hydraulic coupling mechanisms that use a lock member to connect and release the two oscillating portions among the plurality of oscillating portions. A variable valve mechanism of a cam switching type that selects a use cam that is a cam used to drive
A determination unit that determines at least one of a state of the locking member and a switching state of the use cam according to the state of the lock member based on a change mode of hydraulic pressure that changes according to the change of the use cam; An internal combustion engine. The internal combustion engine according to claim 1,
The determination unit is a hydraulic pressure that changes according to the movement of the lock member in a connection mechanism that performs connection or disconnection when the use cam is switched among the plurality of connection mechanisms, and the valve is not lifted. An internal combustion engine that determines completion of operation of the lock member in a connection mechanism that performs connection or disconnection at the time of switching of the use cam among the plurality of connection mechanisms, based on a detected and stored hydraulic pressure value and change width. The internal combustion engine according to claim 1 or 2,
The variable valve mechanism is provided with an oil passage that penetrates the plurality of swinging portions in a state where the valve is not lifted,
An internal combustion engine in which the determination unit determines the use cam based on a reduction mode including whether or not the hydraulic pressure transmitted by the oil passage is reduced. An internal combustion engine according to claim 3,
The variable valve mechanism is provided on at least one of the intake side and the exhaust side, and the rocker arm portion is provided for each cylinder of a plurality of cylinders,
The rocker arm portion shares the oil path between the plurality of cylinders on at least one of the intake side and the exhaust side, or the rocker arm portion is the plurality of cylinders on the intake side and the exhaust side An internal combustion engine that shares the oil passage between the intake side and the exhaust side while the variable valve mechanism shares the oil passage. The internal combustion engine according to claim 3 or 4,
An internal combustion engine in which the oil passage also serves as a lubricating oil passage for supplying oil for lubrication. An internal combustion engine according to any one of claims 3 to 5,
An internal combustion engine in which the oil passage is an oil passage different from an oil passage that supplies hydraulic pressure to the plurality of coupling mechanisms.

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