JP5781331B2 - Valve operating device for internal combustion engine - Google Patents

Description

  The present invention relates to a valve operating apparatus for an internal combustion engine for driving an intake valve and an exhaust valve of the internal combustion engine, and a valve driving method for the internal combustion engine.

  In order to increase the degree of freedom of control of an internal combustion engine, there is a hydraulic valve drive device that controls an intake valve and an exhaust valve using a hydraulic actuator, a hydraulic servo valve, and the like instead of a cam drive. For example, there has been proposed a valve driving device in which only an opening / closing operation (lift) of a valve is performed by an actuator (Patent Document 1). Further, Patent Document 2 describes a servo valve provided with a nozzle flapper mechanism.

JP 2009-257319 A JP 2010-060128 A

  By the way, although the valve drive device described in Patent Document 1 enables free valve control, it is necessary to increase the reliability in consideration of the failure probability of the hydraulic actuator.

  The present invention solves the above-described problems, and an object thereof is to provide a valve operating device for an internal combustion engine and a valve driving method for the internal combustion engine in which the reliability of the hydraulic actuator is improved.

  In order to achieve the above-described object, a valve operating apparatus for an internal combustion engine according to the present invention operates with a control signal to switch a supply target of hydraulic oil pressure, and an operation switched by the direction switching control valve. A valve drive piston capable of driving at least one of an exhaust valve and an intake valve of an internal combustion engine by reciprocating in a valve drive cylinder according to a supply target of oil pressure; and the valve drive cylinder and the direction switching control valve; And a safety valve for lowering the hydraulic pressure between the two.

  Thereby, even if the intake valve or the exhaust valve is operating at high speed, the safety valve operates and the valve drive piston can be retracted and stored in the valve drive cylinder. For this reason, the spool of the direction switching control valve does not move after the valve drive piston contracts into the valve drive cylinder. As a result, the valve drive piston does not protrude from the valve drive cylinder, and the possibility that the valve drive piston protrudes and collides with the intake valve or the exhaust valve is reduced.

  As a desirable mode of the present invention, it includes valve drive piston displacement detection means for detecting the displacement of the valve drive piston, and a control device for transmitting the control signal, wherein the control device includes the control signal and the displacement detection means. It is preferable to calculate a deviation from the detected piston displacement signal and to operate the safety valve when the deviation exceeds a predetermined threshold value. As a result, regardless of the state of the spool, the valve drive piston does not move after contracting into the valve drive cylinder. For this reason, the valve drive piston can be stored in the valve drive cylinder without considering the time required for the movement of the spool. As a result, the possibility that the valve drive piston protrudes and collides with the intake valve or the exhaust valve to be damaged is reduced.

  A desirable aspect of the present invention includes a spool that changes a supply target of hydraulic oil pressure of the direction switching control valve, a spool displacement detection unit that detects a displacement of the spool, and a control device that transmits the control signal. Preferably, the control device calculates a deviation between the control signal and the spool displacement detected by the spool displacement detection means, and operates the safety valve when the deviation exceeds a predetermined threshold value. Thereby, the valve drive piston can be stored in the valve drive cylinder in consideration of the operation delay of the valve drive piston caused by the spool in advance. As a result, the possibility that the valve drive piston protrudes and collides with the intake valve or the exhaust valve to be damaged is reduced.

  In order to achieve the above object, the valve drive method for an internal combustion engine according to the present invention can drive at least one of an exhaust valve and an intake valve of the internal combustion engine by a valve drive piston that reciprocates with a drive force in a valve drive cylinder. A valve driving method for calculating a deviation between a valve driving control signal and a valve driving piston displacement signal, and when the deviation exceeds a predetermined threshold value, a safety valve operation for contracting the valve driving piston. A signal is transmitted.

  Thereby, even if the intake valve and the exhaust valve are operating at high speed, the safety valve operates and the valve drive piston can be retracted and stored in the valve drive cylinder. For this reason, the spool does not move after the valve drive piston contracts into the valve drive cylinder. As a result, the valve drive piston does not protrude from the valve drive cylinder, and the possibility that the valve drive piston protrudes and collides with the intake valve or the exhaust valve is reduced.

  ADVANTAGE OF THE INVENTION According to this invention, the valve operating apparatus of the internal combustion engine which improved the reliability of the hydraulic actuator, and the valve operating drive method of an internal combustion engine can be provided.

FIG. 1 is a configuration diagram of a valve gear for an internal combustion engine according to the present embodiment. FIG. 2 is a schematic diagram of the valve drive device. FIG. 3 is a configuration diagram of the control device. FIG. 4 is an explanatory diagram illustrating an example of a hydraulic circuit according to the present embodiment. FIG. 5 is an explanatory view showing an example of a nozzle flapper mechanism. FIG. 6 is a flowchart showing the operation of the valve gear according to the present embodiment. FIG. 7 is an explanatory view showing the operation of the valve drive piston according to the present embodiment. FIG. 8 is an explanatory view showing the operation of the valve drive piston according to the present embodiment. FIG. 9 is an explanatory diagram showing a block diagram of the valve gear for the internal combustion engine according to the present embodiment. FIG. 10 is an explanatory diagram showing the operation of the valve drive piston according to the present embodiment.

  DESCRIPTION OF EMBODIMENTS Embodiments (embodiments) for carrying out the present invention will be described in detail with reference to the drawings. The present invention is not limited by the contents described in the following embodiments. The constituent elements described below include those that can be easily assumed by those skilled in the art and those that are substantially the same. Furthermore, the constituent elements described below can be appropriately combined.

  The present embodiment will be described with reference to the drawings. FIG. 1 is a configuration diagram of a valve gear for an internal combustion engine according to the present embodiment. FIG. 2 is a schematic diagram of the valve drive device. FIG. 3 is a configuration diagram of the control device. A valve operating apparatus 100 (hereinafter referred to as a valve operating apparatus) for an internal combustion engine according to the present embodiment includes an exhaust valve 4 a serving as an engine valve and an engine valve as the combustion piston 2 moves up and down in the cylinder block 3. This is a device for driving the intake valve 4b.

  As shown in FIG. 1, the valve operating apparatus 100 includes a valve driving device 10 installed in the internal combustion engine 1 (engine), measuring devices 20 and 21 that measure the state of the internal combustion engine 1, and hydraulic pressure to the valve driving device 10. Is provided with a hydraulic unit 30 for supplying pressure, a control device 80 for controlling the valve driving device 10, signal lines I1, I2, I3, I4, and I5, and hydraulic lines O1 and O2. The dynamo 200 is a power conversion device. The dynamo 200 is not an essential component but an additional element, and is used, for example, when used as a test apparatus.

  As shown in FIG. 2, the valve drive device 10 includes a valve drive cylinder 11, a valve drive piston 12 movably accommodated in the valve drive cylinder 11, and a servo valve 13 for driving the valve drive piston 12. And a valve drive piston displacement meter 15 for measuring the position of the valve drive piston 12. As shown in FIG. 1, the internal combustion engine 1 includes a cylinder block 3, a crankcase 9, a combustion piston 2, a crankshaft 7, and a connecting rod 8. The combustion piston 2 and the crankshaft 7 are connected by a connecting rod 8. With such a structure, the reciprocating motion of the combustion piston is converted into rotational motion by the crankshaft 7. If the valve drive device 10 breaks down and stops with the valve drive piston 12 protruding, the combustion piston 2 continues to reciprocate due to inertia, so that the valve drive piston 2 protrudes and collides with the intake valve or the exhaust valve. There is a risk of damage.

  As shown in FIGS. 1 and 2, the internal combustion engine 1 includes an exhaust valve 4 a and an intake valve 4 b, a valve rod 5, and a valve spring 6. The exhaust valve 4 a and the intake valve 4 b are each fixed to the lower end of the valve rod 5, and force is urged in the valve closing direction by a valve spring 6 provided on the valve rod 5. The valve drive device 10 is mounted on the internal combustion engine 1, and a valve drive piston 12 is connected to the valve rod 5. Alternatively, the valve driving device 10 is disposed with a slight gap when the valve is closed. Thus, when the valve drive piston 12 is driven, the exhaust valve 4 a and the intake valve 4 b are driven according to the valve rod 5. When the valve drive piston 12 is connected to the valve rod 5, the valve spring 6 is not necessary.

  The valve drive piston 12 movably accommodated in the valve drive cylinder 11 shown in FIG. 2 is a hydraulic actuator, and the valve drive piston 12 extends when the hydraulic pressure is supplied to the valve drive cylinder 11 and extends to the exhaust valve 4a or The intake valve 4b is opened. Further, the valve drive piston 12 contracts when the hydraulic pressure is discharged from the valve drive cylinder 11, and closes the exhaust valve 4a or the intake valve 4b. The servo valve 13 is attached to the outer side surface of the valve drive cylinder 11. The servo valve 13 is connected to a later-described hydraulic unit 30 through a hydraulic line O1 that is a hydraulic supply line and a hydraulic line O2 that is a return line. The servo valve 13 controls the supply of hydraulic pressure to the valve drive cylinder 11 or the discharge of hydraulic pressure from the valve drive cylinder 11 based on an instruction of the signal line I2 from the control device 80. For example, the servo valve 13 includes a spool, an oil passage, a nozzle flapper mechanism, and the like, which will be described later. The valve drive piston displacement meter 15 measures the position of the valve drive piston 12 in the valve drive cylinder 11 and outputs the measured position data to the control device 80.

  A measuring device 20 shown in FIG. 1 is an encoder that measures the rotational speed of the internal combustion engine 1. The measuring device 21 is a crank angle sensor that measures the crank angle of the internal combustion engine 1. The rotational speed information and crank angle information of the internal combustion engine 1 measured by the measuring devices 20 and 21 are output to the control device 80. Here, the number of rotations refers to a rotation speed that is an angle change per unit time at each crank angle.

  The control device 80 is a device that controls the valve driving device 10. As shown in FIG. 1, the control device 80 performs control to start or stop the hydraulic unit 30 via the signal line I1. Further, the control device 80 can control the servo valve 13 via the signal line I2. The control device 80 is connected to the valve drive piston displacement meter 15 and the measurement devices 20 and 21 via signal lines I3, I4, and I5. Next, the control device 80 will be described with reference to FIG.

  The control device 80 illustrated in FIG. 3 includes an input processing circuit 81, an input port 82, a processing unit 90, a storage unit 94, an output port 83, and an output processing circuit 84. The processing unit 90 includes, for example, a CPU (Central Processing Unit) 91, a RAM (Random Access Memory) 92, and a ROM (Read Only Memory) 93. The control device 80 may be accompanied by a display device 85 and an input device 86. A display device 85 and an input device 86 can be connected to the control device 80 as necessary. Further, the control device 80 can operate without the display device 85 and the input device 86.

  The processing unit 90, the storage unit 94, and the input port 82 and the output port 83 are connected via a bus 87, a bus 88, and a bus 89. By the bus 87, the bus 88, and the bus 89, the CPU 91 of the processing unit 90 is configured to exchange control data with the storage unit 94, the input port 82, and the output port 83 and to issue commands to one side. The

  An input processing circuit 81 is connected to the input port 82. For example, measurement data is is connected to the input processing circuit 81. The measurement data is is converted into a signal that can be used by the processing unit 90 by a noise filter, an A / D converter, or the like provided in the input processing circuit 81, and then sent to the processing unit 90 via the input port 82. Thereby, the processing unit 90 can acquire necessary information. The measurement data is is, for example, displacement data, crank angle data, and rotation speed data acquired from the valve drive piston displacement meter 15 and the measurement devices 20 and 21 via signal lines I3, I4, and I5.

  An output processing circuit 84 is connected to the output port 83. The output processing circuit 84 is connected to a display device 85 and an external output terminal. The output processing circuit 84 includes a display device control circuit, a control signal circuit such as a valve drive device, a signal amplification circuit, and the like. The output processing circuit 84 outputs the signal data to the servo valve 13 calculated by the processing unit 90 as a display signal to be displayed on the display device 85 or outputs it as an instruction signal id to be transmitted to the servo valve 13. As the display device 85, for example, a liquid crystal display panel, a CRT (Cathode Ray Tube), or the like can be used. The instruction signal id is transmitted to the servo valve 13 via the signal line I2.

  The storage unit 94 stores a computer program including an operation procedure of the valve gear 100. Here, the storage unit 94 can be configured by a volatile memory such as a RAM, a nonvolatile memory such as a flash memory, a hard disk drive, or a combination thereof.

  The computer program may execute the operation procedure of the valve gear 100 in combination with a computer program already recorded in the processing unit 90. Moreover, this control apparatus 80 may perform the operation | movement procedure of the valve operating apparatus 100 using dedicated hardware instead of a computer program.

  The operation procedure of the valve operating apparatus 100 can also be realized by executing a program prepared in advance on a personal computer, a workstation, or a computer system such as a control computer. The program is recorded on a computer-readable recording medium such as a recording device such as a hard disk, a flexible disk (FD), a ROM, a CD-ROM, an MO, a DVD, or a flash memory, and is read from the recording medium by the computer. Can also be implemented. Here, the “computer system” includes an OS and hardware such as peripheral devices.

  In addition, the “computer-readable recording medium” dynamically stores the program for a short time, such as a communication line when the program is transmitted via a network such as the Internet or a communication line network such as a telephone line. What is held, and what holds a program for a certain period of time, such as volatile memory inside a computer system serving as a server or client in that case, are included. Further, the program may be for realizing a part of the above-described functions, and may be capable of realizing the above-described functions in combination with a program already recorded in the computer system. .

  The control device 80 described above acquires crank angle and rotation speed data from the measurement devices 20 and 21. In the present embodiment, it is assumed that the control device 80 stores a target lift waveform to which a lift amount is originally given for each desired crank angle in the storage unit 94 or the RAM 92. For example, in a 4-stroke engine, one cycle is completed by performing four strokes of intake, compression, expansion, and exhaust while the combustion piston reciprocates twice. The control device 80 generates a target lift waveform for one cycle, and sends a control command as a control signal to the servo valve so that the valve drive piston can be driven with the same drive waveform as the target lift waveform.

  Next, the hydraulic circuit according to this embodiment will be described. FIG. 4 is an explanatory diagram illustrating an example of a hydraulic circuit according to the present embodiment. The hydraulic circuit 10A shown in FIG. 4 drives the valve drive cylinder 11 of the valve drive device 10 shown in FIG. 2, the valve drive piston 12 movably accommodated in the valve drive cylinder 11, and the valve drive piston 12. The hydraulic circuit with the servo valve 13 is shown.

  The hydraulic circuit 10A includes a valve drive cylinder 11, a valve drive piston 12, a direction switching control valve mechanism 18 having a spool 17, a nozzle flapper mechanism 60, oil passages 41, 42, 43, 44, 45, 46, 47, 48 and 49, and apertures 68 and 69 are included. The stroke (displacement) of the spool 17 is measured by a non-contact type spool displacement meter 19 such as an LVDT (Linear Variable Differential Transformer). The spool displacement meter 19 is connected to the control device 80 described above through a signal line I6. Similarly, the stroke (displacement) of the valve drive piston 12 is measured by a non-contact type valve drive piston displacement meter 15. The valve drive piston displacement meter 15 is connected to the control device 80 described above through a signal line I3. Moreover, piping 71, 72, 73, 74, 75, 76, 77 is provided as needed. The oil passages 41, 42, 44, 45, 47, 48, 49 and the pipe 77 are connected to the oil ports 51, 52, 53, 54, 55, 56, 57, 58.

  The hydraulic circuit 10A is connected to the piston withdrawal hydraulic circuit 110. The piston retracting hydraulic circuit 110 includes a safety valve 111, a safety valve operating valve mechanism 112, a tank 113, and oil passages 121, 122, 123, 124, and 125. Further, the safety valve operating valve mechanism 112 is connected to the control device 80 described above through a signal line I2 shown in FIG. The oil passage 124 is connected to the oil port 129.

  The direction switching control valve mechanism 18 is a three-way switching control valve that can switch in three directions. The direction switching control valve mechanism 18 can switch the oil passages 45 and 48 connected to the oil passage 46 leading to the valve drive cylinder 11 by the movement of the spool 17. Thereby, the supply target of the hydraulic oil pressure supplied to the oil passage 46 can be switched.

  The nozzle flapper mechanism 60 is a mechanism that changes the pressure by reducing the flow area of the nozzle. As shown in FIG. 4, a nozzle flapper mechanism 60 is interposed in the oil passage 41. The oil passage 41 includes an oil passage 41A on the side of the pipe connection 43a from the nozzle flapper mechanism 60 to the oil passages 42 and 43, and an oil passage 41B on the side of the oil port 51 from the nozzle flapper mechanism 60.

  FIG. 5 is an explanatory view showing an example of a nozzle flapper mechanism. As shown in FIG. 5, the nozzle flapper mechanism 60 is disposed between the oil passage 41A and the oil passage 41B. The nozzle flapper mechanism 60 includes a pipe 41 a of the oil passage 41, a nozzle 63, a flapper 61, and a nozzle flapper driving means 62. The nozzle flapper mechanism 60 is connected to the tank 79 through the oil port 51. A nozzle 63 is provided in the pipe 41 a of the oil passage 41. The flapper 61 is a member that can restrict or open the flow path area of the nozzle 63. The nozzle flapper driving means 62 can be constituted by an electromagnetic coil such as a piezoelectric body or a solenoid. The nozzle flapper driving means 62 is connected to the control device 80 described above via a signal line I2.

  The control device 80 described above transmits a control signal command, and the nozzle flapper driving means 62 shown in FIG. 5 expands and contracts in accordance with the control signal command. Along with the expansion and contraction of the nozzle flapper driving means 62, the pressure of the oil passage 41A can be changed by the flapper 61 restricting or opening the flow passage area of the nozzle.

  The oil passage 42 shown in FIG. 4 is connected to the hydraulic unit 30 via the oil port 52, and a pilot pressure is applied. The restrictor 68 is an orifice and is a pressure restrictor for adjusting the pilot pressure.

  The oil passage 43 is connected to the oil passage 41 </ b> A and the oil passage 42 by a pipe connection 43 a. The oil passage 43 is also a pressing portion that presses the spool 17 of the direction switching control valve mechanism 18. The oil passage 44 is connected to the hydraulic unit 30 via the oil port 53, and a pilot pressure is applied thereto.

  The oil passage 45 is connected to the hydraulic unit 30 via the oil port 54, and the first hydraulic oil pressure of the valve drive piston 12 is applied thereto. The direction switching control valve mechanism 18 switches the connection between the oil passage 45 and the oil passage 46 according to the position of the spool 17.

  The oil passage 46 connects the direction switching control valve mechanism 18 and the valve drive cylinder upper chamber 11 a of the valve drive cylinder 11. The oil passage 49 is connected to the oil passage 46 through a pipe connection 46 a between the direction switching control valve mechanism 18 and the valve drive cylinder upper chamber 11 a of the valve drive cylinder 11. The oil passage 49 is connected to the oil passage 121 of the piston retract hydraulic circuit 110 via the oil port 58. Here, the valve drive cylinder upper chamber 11a is a space in the valve drive cylinder 11, and is a space surrounded by the valve drive piston 12 and the valve drive cylinder 11 on the opposite side of the valve rod 5 shown in FIG. . A pipe 71 is connected to the valve drive cylinder upper chamber 11a, and the pipe 71 acts to vent air as necessary.

  The valve drive cylinder lower chamber 11b is a space surrounded by the valve drive piston 12 and the valve drive cylinder 11 on the valve rod 5 side shown in FIG. The oil passage 47 is connected to the hydraulic unit 30 via the oil port 57, and the second hydraulic oil pressure of the valve drive piston 12 is applied thereto. The oil passage 47 is provided with a throttle 69. The restrictor 69 is an orifice and is a pressure restrictor for adjusting the second hydraulic oil pressure. It is preferable that the second hydraulic oil pressure is set to be smaller than the first hydraulic oil pressure described above by the throttle 69. The oil passage 47 has a pipe connection 47a to which a pipe 72 is connected. The pipe 72 acts to remove air as necessary.

  The oil passage 48 is a return pipeline from the direction switching control valve mechanism 18 and is connected to the oil tank via the oil port 55.

  The pipes 73, 74, 75, 76 and 77 are drain pipes, and moisture is discharged through the oil port 56. The oil ports 51, 52, 53, 54, 55, 56, 57, and 58 are openings that carry oil or moisture that are opened to the servo valve 13.

  The piston retraction hydraulic circuit 110 is a hydraulic circuit for contracting the valve drive piston 12 into the valve cylinder regardless of the operation of the direction switching control valve mechanism 18 in an emergency. The safety valve 111 is a pressure balanced relief valve, and includes a pilot piston 111a and a spring 111b. The safety valve 111 is connected to the oil passage 46 described above via the oil passage 121. The safety valve 111 is connected to the safety valve operating valve mechanism 112 via the oil passage 122. In the safety valve 111, the spring pressure of the spring 111b and the hydraulic pressure from the safety valve operating valve mechanism 112 are set so that the pilot piston 111a closes the oil path even under the maximum pressure from the oil path 121 used during normal driving of the valve gear 100. ing. For example, the interval at which the intake valve or exhaust valve opens and closes is several to several tens of milliseconds, such as 20 milliseconds, so that the pressure set so that the pilot piston 111a closes the oil passage has a response speed of the intake valve or exhaust valve. It is preferable that the pressure and the area of the pilot piston be set so that the valve can be opened at intervals of opening and closing of the valve. The oil path 123 is a return path for returning the hydraulic oil to the tank 113 when the safety valve 111 is operated.

  The safety valve operating valve mechanism 112 is connected to the oil passage 124. The oil passage 124 is connected to the hydraulic unit 30 through an oil port 129, and pilot pressure is applied. The safety valve operating valve mechanism 112 connects the oil passage 124 and the oil passage 122 so as to supply pilot pressure to the safety valve 111 when the valve operating apparatus 100 is normally driven. In an emergency, the safety valve operating valve mechanism 112 receives the control signal of the control device 80 from the signal line I2 and drives the solenoid or the like, or turns off the power of the solenoid and the oil path 122 by the biased spring force or the like. Is a direction switching control valve capable of switching to an oil passage 125 connected to the tank 113.

  When the oil passage 122 is switched to the oil passage 125 connected to the tank 113, the safety valve 111 loses the pilot pressure received by the pilot piston 111 a, loses equilibrium, and performs an operation of connecting the oil passage 121 to the oil passage 123. As a result, hydraulic oil is supplied to the tank 113 through the oil passage 123.

  As described above, the valve operating apparatus for an internal combustion engine according to the present embodiment includes a servo valve having a spool that controls the flow direction and pressure of hydraulic pressure that operates according to a control signal, and valve drive according to the hydraulic pressure controlled by the spool. A valve drive piston capable of driving an exhaust valve or an intake valve of an internal combustion engine that moves in a piston motion in the cylinder, and a safety valve that lowers the hydraulic pressure between the valve drive cylinder and the servo valve.

  Thereby, even if the intake valve and the exhaust valve are operating at high speed, the safety valve operates and the valve drive piston can be retracted and stored in the valve drive cylinder. For this reason, the spool does not move after the valve drive piston contracts into the valve drive cylinder. As a result, the valve drive piston does not protrude from the valve drive cylinder, and the possibility that the valve drive piston protrudes and collides with the intake valve or the exhaust valve is reduced.

  Next, the operation of the valve gear according to the present embodiment will be described with reference to FIGS. FIG. 6 is a flowchart showing the operation of the valve gear according to the present embodiment. 7 and 8 are explanatory views showing the operation of the valve drive piston according to the present embodiment. FIG. 9 is an explanatory diagram showing a block diagram of the valve gear for the internal combustion engine according to the present embodiment. FIG. 10 is an explanatory diagram showing the operation of the valve drive piston according to the present embodiment.

  As shown in FIG. 6, the control device 80 of the valve gear 100 transmits a command of a control signal to the servo valve 13 (step S1). As shown in FIGS. 1 and 2, the control signal command from the control device 80 is transmitted to the servo valve 13 via the signal line I2. In the servo valve 13, the nozzle flapper driving means 62 of the nozzle flapper mechanism 60 shown in FIG. 5 expands and contracts according to the command of the control signal.

  When the nozzle flapper driving means 62 shown in FIG. 5 is driven and the pressure of the oil passage 41A is changed by reducing the flow passage area of the nozzle 63, the pilot pressure is not reduced in the oil passage 42 as shown in FIG. And applied to the oil passage 43. The pressure PPB is applied to the oil passage 43. As described above, the pilot pressure is also applied to the oil passage 44. Here, the pressure applied to the oil passage 44 is defined as a pressure PPA.

  In the present embodiment, the throttle 68 is set so that the pressure PPA is approximately half of the pressure PPB when the nozzle flapper driving means 62 shown in FIG. It is preferable. As a result, when the nozzle flapper driving means 62 shown in FIG. 5 is driven and the flow area of the nozzle 63 is reduced by a predetermined amount or more, the pressure PPB becomes larger than the pressure PPA and the spool 17 moves. When the spool 17 moves, the spool displacement meter 19 reads the displacement of the spool, and the spool displacement meter 19 sends the displacement information of the spool to the control device 80 through the signal line I6.

  As the spool 17 moves, the direction switching control valve mechanism 18 connects the oil passage 45 and the oil passage 46. As a result, the valve drive cylinder upper chamber 11a becomes the first hydraulic oil pressure and becomes larger than the second hydraulic oil pressure of the valve drive cylinder lower chamber 11b, so that the valve drive piston 12 becomes the valve rod 5 shown in FIG. In the direction of arrow Z1 shown in FIG. The displacement of the valve drive piston 12 is measured by the valve drive piston displacement meter 15 shown in FIG. 2, and the valve drive piston displacement meter 15 sends piston displacement information to the control device 80 through the signal line I3.

  When the nozzle flapper driving means 62 shown in FIG. 5 is driven and the pressure of the oil passage 41A is changed by opening the throttle of the passage area of the nozzle 63, the pilot pressure of the oil passage 42 is reduced as shown in FIG. The For this reason, the pressure applied to the oil passage 43 is also reduced. As a result, the PPB applied to the oil passage 43 becomes smaller than the pressure PPA applied to the oil passage 44.

  That is, the pressure PPA is driven by the nozzle flapper driving means 62 shown in FIG. 5, and when the restriction of the flow passage area of the nozzle 63 is opened more than a predetermined amount, the pressure PPA becomes larger than the pressure PPB and the spool 17 moves. When the spool 17 moves, the spool displacement meter 19 reads the displacement of the spool, and the spool displacement meter 19 sends the displacement information of the spool to the control device 80 through the signal line I6.

  As the spool 17 moves, the direction switching control valve mechanism 18 switches the connection between the oil passage 45 and the oil passage 46 to the connection between the oil passage 48 and the oil passage 46. As a result, the valve drive cylinder upper chamber 11a becomes the pressure of the return line, and becomes smaller than the second hydraulic oil pressure in the valve drive cylinder lower chamber 11b, so that the valve drive piston 12 of the valve rod 5 shown in FIG. It moves in the opposite direction, the direction of the arrow Z2 shown in FIG. The displacement of the valve drive piston 12 is measured by the valve drive piston displacement meter 15 shown in FIG. 2, and the valve drive piston displacement meter 15 sends piston displacement information to the control device 80 through the signal line I3.

  As described above, the valve operating apparatus for an internal combustion engine according to the present embodiment operates in response to a control signal, and changes the pressure by reducing the flow area of the nozzle, according to the operation of the nozzle flapper mechanism. A direction switching control valve for switching the supply target of the hydraulic oil pressure, and a reciprocating motion in the valve drive cylinder according to the supply target of the hydraulic oil pressure switched by the direction switching control valve, so that the exhaust valve and the intake valve of the internal combustion engine A valve drive piston capable of driving at least one of the valves, and when the pressure is changed by narrowing the flow area of the nozzle of the nozzle flapper mechanism, the direction switching control valve is switched according to the change in the pressure. The supply target of the hydraulic oil pressure changes, and the valve drive piston protrudes from the valve drive cylinder according to the supply target of the hydraulic oil pressure. Conversely, when the pressure is changed by opening the nozzle flow area of the nozzle flapper mechanism, the supply target of the hydraulic oil pressure is changed by the direction switching control valve, and the supply target of the hydraulic oil pressure is changed. Then, the valve drive piston moves in a direction (contracted direction) in which it is stored in the valve drive cylinder.

  Thereby, when the electric system of the nozzle flapper mechanism 60 fails, the flow path area of the nozzle 63 of the nozzle flapper mechanism 60 is not reduced according to the control signal. Since the pressure PPA cannot be driven by the nozzle flapper driving means 62 shown in FIG. 5, the restriction of the flow path area of the nozzle 63 remains open for a predetermined amount or more. For this reason, as shown in FIG. 8, the pressure PPA remains higher than the pressure PPB, and the direction switching control valve mechanism 18 connects the oil passage 45 and the oil passage 46, and the oil passage 48 and the oil passage 46. Switch to the connection. Once the valve drive piston 12 contracts into the valve drive cylinder 11 according to the movement of the spool 17 (operation in the Z2 direction), the spool 17 does not move thereafter. As a result, the valve drive piston 12 does not protrude from the valve drive cylinder 11 in accordance with the movement of the spool 17, and the possibility that the valve drive piston 12 protrudes and collides with the intake valve 4b or the exhaust valve 4a is reduced. Is done.

  Further, in the valve operating apparatus for an internal combustion engine of the present embodiment, when the valve drive piston 12 moves in the valve drive cylinder 11, the oil pressure of the oil passage 46 increases and decreases. Here, the above-described safety valve 111 connected to the oil passage 46 via the oil passage 121 is in a state in which the pilot piston 111a is closed even if the oil pressure of the oil passage 46 is increased or decreased. In this case, the piston retracting hydraulic circuit 110 does not affect the hydraulic circuit 10A.

  In the valve operating apparatus for the internal combustion engine of the present embodiment, when the control device 80 transmits a command of a control signal to the servo valve 13 (step S1), the control device 80 next calculates a deviation from the piston displacement (step S2). ). Therefore, the CPU 91 feeds back piston displacement data as will be described based on the block diagram shown in FIG.

  The block diagram shown in FIG. 9 has a control device block G1, a spool block G2, and a valve drive piston block G3. The target lift displacement LF based on the control signal command of the control device block G1 and the feedback piston displacement signal PS2 of the piston displacement signal PS1 measured by the valve drive piston displacement meter 15 are added at the addition point Q1, and the CPU 91 receives the control signal. The deviation between the target lift displacement LF and the piston displacement PS2 based on the command is calculated and stored in the storage unit 94 or the RAM 92. The CPU 91 feedback-controls a deviation between the target lift displacement LF and the piston displacement PS1 to the target lift displacement LF based on the control signal command of the control device block G1, and generates a PID-controlled spool displacement control signal FB1.

  The spool displacement control signal FB1 and the feedback spool displacement signal SP2 of the spool displacement signal SP1 measured by the spool displacement meter 19 are added at the addition point Q2, and the CPU 91 calculates the spool displacement based on the spool displacement control signal FB1 and the spool displacement SP2. The deviation is calculated and stored in the storage unit 94 or the RAM 92. The CPU 91 feedback-controls the deviation between the spool displacement based on the spool displacement control signal FB1 and the spool displacement SP2, and generates a PID-controlled spool displacement control signal FB2. The spool block G2 converts the spool displacement control signal FB2 with a predetermined transfer function to obtain a spool displacement signal SP1. The valve drive piston block G3 converts the spool displacement signal SP1 with a predetermined transfer function to obtain a piston displacement signal PS1. When the controller 80 calculates the deviation from the piston displacement (step S2), the process proceeds to the next step.

  Next, the control device 80 determines whether the deviation from the piston displacement exceeds a predetermined threshold value (step S3). This threshold value is stored in advance in the storage unit 94 or the RAM 92. The control device 80 reads a predetermined threshold value into the work area of the RAM 92 and compares it with a deviation from the calculated piston displacement. When the deviation from the piston displacement exceeds a predetermined threshold value (step S3, Yes), the control device 80 proceeds to the safety valve control (step S6) described later. When the deviation from the piston displacement does not exceed the predetermined threshold (No at Step S3), the control device 80 calculates the deviation from the spool displacement described above (Step S4).

  The controller 80 calculates the deviation from the spool displacement described above (step S4) because the valve operating device of the internal combustion engine of the present embodiment determines the moving direction of the valve drive piston 12 in conjunction with the operation of the spool 17. Therefore, it is important to monitor whether the operation of the spool 17 is appropriate. Note that step S4 and step 5 described later may be omitted, and if the deviation from the piston displacement does not exceed a predetermined threshold value, the control signal may be returned to command transmission (step S1).

  Next, the control device 80 determines whether or not the deviation from the spool displacement exceeds a predetermined threshold value (step S5). This threshold value is stored in advance in the storage unit 94 or the RAM 92. The control device 80 reads a predetermined threshold value into the work area of the RAM 92 and compares it with a deviation from the calculated spool displacement. When the deviation from the spool displacement exceeds a predetermined threshold value (step S5, Yes), the control device 80 proceeds to the safety valve control (step S6). When the deviation from the piston displacement does not exceed the predetermined threshold value (No in step S5), the control device 80 returns to the command transmission of the control signal (step S1).

  Next, in the control of the safety valve (step S6), the control device 80 transmits a control signal to the safety valve operating valve mechanism 112 through the signal line I2, and opens the safety valve 111. For example, the solenoid of the safety valve operating valve mechanism 112 shown in FIG. 10 is driven and the oil passage 122 that has supplied the pilot pressure to the safety valve 111 is switched to the connection with the oil passage 125, and the pilot pressure in the oil passage 122 is released. Is done. Alternatively, if the pilot valve is released when the safety valve operating valve mechanism 112 is turned off, the control device 80 performs control to stop the power supply to the safety valve operating valve mechanism 112. If the driving means of the safety valve operating valve mechanism 112 is a piezoelectric body, the voltage application is stopped. If the drive means of the safety valve operating valve mechanism 112 is a solenoid, the current for excitation is stopped. Thereby, for example, the safety valve operating valve mechanism 112 can be operated even during a power failure.

  When the oil passage 122 is switched to the oil passage 125 connected to the tank 113, the safety valve 111 loses the pilot pressure received by the pilot piston 111 a, loses equilibrium, and performs an operation of connecting the oil passage 121 to the oil passage 123. For this reason, the oil passage 46 is decompressed regardless of the operation state of the direction switching control valve mechanism 18. As a result, the valve drive cylinder upper chamber 11a becomes the pressure of the return line and becomes smaller than the second hydraulic oil pressure in the valve drive cylinder lower chamber 11b, so that the valve drive piston 12 is the reverse of the valve rod shown in FIG. Direction, the direction of the arrow Z2 shown in FIG.

  As described above, the valve operating apparatus for an internal combustion engine according to the present embodiment operates with a control signal to switch a hydraulic oil pressure supply target, and the hydraulic oil pressure switched by the direction switching control valve. Between a valve drive piston capable of driving at least one of an exhaust valve and an intake valve of an internal combustion engine, and between the valve drive cylinder and the direction switching control valve. And a safety valve for lowering the hydraulic pressure.

  Thereby, even if the intake valve or the exhaust valve is operating at high speed, the safety valve operates and the valve drive piston can be retracted and stored in the valve drive cylinder. For this reason, the spool does not move after the valve drive piston contracts into the valve drive cylinder. As a result, the valve drive piston does not protrude from the valve drive cylinder, and the possibility that the valve drive piston protrudes and collides with the intake valve or the exhaust valve is reduced.

  Next, the control device 80 controls the nozzle flapper (step S6). The control device 80 opens the nozzle aperture of the nozzle flapper mechanism 60. For example, the nozzle flapper driving means 62 shown in FIG. 5 is driven to change the pressure of the oil passage 41 </ b> A by opening the restriction of the passage area of the nozzle 63. Alternatively, when the nozzle flapper driving means 62 is turned off, the control device 80 performs control to stop the power supply of the nozzle flapper driving means 62 as long as it is a mechanism that opens the restriction of the flow path area of the contraction nozzle 63. If the nozzle flapper driving means 62 is a piezoelectric body, the voltage application is stopped. If the nozzle flapper driving means 62 is a solenoid, the current for excitation is stopped.

  As shown in FIG. 8, the pilot pressure in the oil passage 42 is reduced. For this reason, the pressure applied to the oil passage 43 is also reduced. As a result, the PPB applied to the oil passage 43 becomes smaller than the pressure PPA applied to the oil passage 44. For this reason, the spool 17 moves only in one direction, and the direction switching control valve mechanism 18 switches the connection between the oil passage 45 and the oil passage 46 to the connection between the oil passage 48 and the oil passage 46. Then, the valve drive cylinder upper chamber 11a becomes the pressure of the return pipe, and becomes smaller than the second hydraulic oil pressure in the valve drive cylinder lower chamber 11b. In this state, the valve drive piston 12 coincides with the state in which the valve rod shown in FIG. 2 moves in the reverse direction of the valve rod and in the direction of the arrow Z2 shown in FIG. And valve drive piston operation can be combined.

  The valve operating apparatus 100 for an internal combustion engine of the present embodiment includes a valve drive piston displacement meter 15 that is a valve drive piston displacement detection means for detecting the displacement of the valve drive piston 12 and a control device 80 that transmits a control signal. The control device 80 calculates a deviation between the control signal and the piston displacement signal detected by the valve drive piston displacement meter 15, and the control device 80 operates the safety valve 111 when the deviation exceeds a threshold value. It is preferable.

  As a result, regardless of the state of the spool, the valve drive piston does not move after contracting into the valve drive cylinder. For this reason, the valve drive piston can be stored in the valve drive cylinder without considering the time required for the movement of the spool. As a result, the possibility that the valve drive piston protrudes and collides with the intake valve or the exhaust valve to be damaged is reduced.

  A valve operating apparatus 100 for an internal combustion engine according to the present embodiment includes a spool 17 that changes a supply target of hydraulic oil pressure of a direction switching control valve mechanism 18, and a spool displacement meter 19 that is a spool displacement detection unit that detects a displacement of the spool 17. And a control device 80 for transmitting a control signal. The control device 80 calculates a deviation between the control signal and the spool displacement detected by the spool displacement meter 19, and the deviation exceeds a threshold value. It is preferable that the control device 80 operates the safety valve 111.

  Since the valve drive piston is interlocked with the operation of the spool, the operation delay and operation failure of the valve drive piston due to the spool failure are detected in advance. The valve drive piston can be stored in the valve drive cylinder in consideration of the operation delay of the valve drive piston caused by the spool in advance. As a result, the possibility that the valve drive piston protrudes and collides with the intake valve or the exhaust valve to be damaged is reduced.

  As described above, the valve drive method of the internal combustion engine is a valve drive method that can drive at least one of the exhaust valve and the intake valve of the internal combustion engine by the valve drive piston that reciprocates with the drive force in the valve drive cylinder. And calculating a deviation between the valve drive control signal and the displacement signal of the valve drive piston, and if the deviation exceeds a predetermined threshold value, a safety valve operation signal for contracting the valve drive piston may be transmitted. it can. Thereby, even if the intake valve or the exhaust valve is operating at high speed, the safety valve operates and the valve drive piston can be retracted and stored in the valve drive cylinder. For this reason, the spool does not move after the valve drive piston contracts into the valve drive cylinder. As a result, the valve drive piston does not protrude from the valve drive cylinder, and the possibility that the valve drive piston protrudes and collides with the intake valve or the exhaust valve is reduced.

  In addition, the valve operating apparatus and the valve operating method according to the present embodiment are also suitable for a testing machine that opens and closes an intake valve or an exhaust valve of an internal combustion engine. The internal combustion engine of the present embodiment preferably drives the cylinder block, the combustion piston that moves up and down in the cylinder block, the exhaust valve and the intake valve, and the exhaust valve and the intake valve. Thereby, it is possible to contribute to the reduction of NOx and unburned HC emissions and the reduction of carbon dioxide emissions by clean exhaust and improved fuel efficiency.

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 2 Piston for combustion 3 Cylinder block 4a Exhaust valve 4b Intake valve 5 Valve rod 6 Valve spring 7 Crankshaft 8 Connecting rod 9 Crankcase 10 Valve drive device 11 Valve drive cylinder 11a Valve drive cylinder upper chamber 11b Valve drive cylinder bottom Chamber 12 Valve drive piston 13 Servo valve 15 Valve drive piston displacement meter 17 Spool 18 Direction switching control valve mechanism 19 Spool displacement meter 20, 21 Measuring device 30 Hydraulic unit 41, 42, 43, 44, 45, 46, 47, 48, 49 Oil path 60 Nozzle flapper mechanism 62 Nozzle flapper driving means 63 Nozzle 80 Control device 100 Valve operating device

Claims (2)

A direction switching control valve that operates in response to a control signal and switches a supply target of hydraulic oil pressure;
A valve drive piston capable of driving at least one of an exhaust valve and an intake valve of an internal combustion engine by reciprocating in a valve drive cylinder according to a supply target of hydraulic oil pressure switched by the direction switching control valve;
A safety valve that reduces the hydraulic pressure between the valve drive cylinder and the direction switching control valve;
A spool for changing a supply target of hydraulic oil pressure of the direction switching control valve;
Spool displacement detecting means for detecting the displacement of the spool;
A control device for transmitting the control signal,
The control device calculates a deviation between the control signal and the spool displacement detected by the spool displacement detection means, and when the deviation exceeds a predetermined threshold, operates the safety valve, and the safety valve This is a pressure balanced relief valve, which has a pilot piston, a spring, and a safety valve operating valve mechanism.
The safety valve operates between the spring pressure of the spring and the operation of the safety valve so that the pilot piston closes the oil passage even at the maximum hydraulic pressure used during normal driving between the valve drive cylinder and the direction switching control valve. The pressure at which the hydraulic pressure from the valve mechanism is set and the pilot piston is set to close the oil passage can open the response speed when the safety valve is operated at the interval at which the intake valve or exhaust valve opens or closes that it is set to a valve gear of an internal combustion engine characterized by. Valve drive piston displacement detecting means for detecting the displacement of the valve drive piston;
A control device for transmitting the control signal,
The said control apparatus calculates the deviation of the said control signal and the piston displacement signal which the said displacement detection means detected, and when the said deviation exceeds a predetermined threshold value, the said safety valve is operated. Of the internal combustion engine.

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