JP2007255299A - Valve system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a valve system improving sealing force when closing a valve. <P>SOLUTION: In this valve system 1 opening/closing an exhaust gas bypass passage 822 for delivering exhaust gas on the upstream side of a turbine 820 to the downstream side thereof so as to bypass the turbine 820 provided in the exhaust passage of an engine with a supercharger, a cylinder device 5 for extending a driving shaft 3 longer than the normal length is provided on the driving shaft 3, and a pressure adjusting means 6 for adjusting internal pressure is connected to the cylinder device 5. The valve system is composed to be switchable to a valve operating mode in which the driving shaft 3 is held to have the normal length by the pressure adjusting means 6 and the opening/closing of a valve body 4 by an actuator 2 is allowed, and a valve closing mode in which the driving shaft 3 is extended longer than the normal length by the pressure adjusting means 6 and the valve body 4 keeps closing while keeping reaction force on the side of the actuator 2. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a valve device that reciprocates a drive shaft of an actuator to open and close a valve body connected to the drive shaft.

  Conventionally, as a two-stage turbo system, a relatively small turbo is arranged upstream of the engine exhaust pipe and used as a high-pressure turbo, and a relatively large turbo is arranged downstream of the high-pressure turbo as a low-pressure turbo. Is known.

  As shown in FIG. 8, in the two-stage turbo system 81, an exhaust manifold 85 and an exhaust pipe 86 are connected to the engine 84. The exhaust pipe 86 is provided with a turbine 820 of the high-pressure stage turbo 82 and a turbine 830 of the low-pressure stage turbo 83 in order from the upstream side, and the exhaust pipe 86 connecting the high-pressure stage turbine 820 and the low-pressure stage turbine 830. The exhaust switching valve device 87 for communicating the exhaust pipe 86 with the exhaust manifold 85 is provided. Further, the high-pressure stage and low-pressure stage turbos 82 and 83 are respectively provided with waste gate valve devices 823 and 833 for communicating the upstream side and the downstream side of each turbine (see, for example, Patent Documents 1 to 3).

  Switching of the operation between the high-pressure stage turbo 82 and the low-pressure stage turbo 83 is performed by the waste gate valve devices 823 and 833 and the exhaust gas switching valve device 87 as shown in FIG.

  When the exhaust gas switching valve device 87 is opened, the high-pressure stage turbo 82 does not operate because the pressure difference between the inlet and outlet of the turbine 820 disappears, and only the low-pressure stage turbo 83 operates.

  When the exhaust switching valve device 87 and the wastegate valve device 823 of the high-pressure stage turbo 82 are fully closed and the wastegate valve device 833 of the low-pressure stage turbo 83 is fully opened, the exhaust gas discharged from the exhaust manifold 85 is All flows to the high-pressure turbine 820 and the high-pressure turbo 82 operates. On the other hand, the low-pressure stage turbo 83 does not operate because the exhaust gas bypasses the turbine 830 by the wastegate valve device 833.

  Further, when the exhaust gas switching valve device 87 is slightly opened and the waste gate valve device 833 of the low-pressure stage turbo 83 is fully closed, the high-pressure stage turbo 82 and the low-pressure stage turbo 83 operate simultaneously.

  As described above, the operation / non-operation of the high-pressure stage turbo 82 and the low-pressure stage turbo 83 can be easily switched by switching between opening and closing of the waste gate valve devices 823 and 833 and the exhaust gas switching valve device 87. .

  On the intake side, the low-pressure stage turbo 83 operates so that the intake switching valve device 100 provided in the intake pipe 89 closes the route (flow path) on the low-pressure stage side when the high-pressure stage turbo 82 operates. When doing so, the route on the high-pressure stage side is closed.

  Here, the waste gate valve devices 823 and 833 installed in the high-pressure stage and the low-pressure stage normally have a structure in which the actuator is operated by the supercharging pressure in the intake pipe 89 in order to prevent turbo overrun. ing.

  As shown in FIG. 10, an exhaust gas bypass passage 822 that communicates the upstream and downstream of the turbine 820 is provided in the turbine casing 91 that houses the turbine 820 of the supercharger 82. The wastegate valve device 823 includes a wastegate valve body 93 provided in the turbine casing 91 for opening and closing the exhaust gas bypass passage 822, a drive shaft 95 connected to the wastegate valve body 93 via a link 94, and a drive thereof. And an actuator 96 that opens and closes the wastegate valve body 93 by reciprocating a shaft 95. In the actuator 96, a diaphragm 97 to which a drive shaft 95 is fixed is provided so as to be movable in the vertical direction. The diaphragm 97 is urged downward by a spring 98. Further, when the pressurized intake of the supercharger 82 is introduced into the actuator 96 so as to urge the diaphragm 97 upward, and the supercharging pressure of the intake exceeds the set force of the spring 98, the wastegate valve body 93 Is now open.

  Further, in the exhaust gas switching valve device 87 (see FIG. 8), an exhaust gas switching valve body is connected to an actuator using air pressure (or vacuum pressure) via a link, and the exhaust gas switching valve is opened and closed by air pressure (not shown). )

JP 59-29726 A Japanese Utility Model Publication No. 5-030431 JP 2004-116432 A

  However, since the exhaust pressure is high in the two-stage turbo system 81, the above-described waste gate valve device 823 has a problem that the sealing force of the waste gate valve body 93 by the spring 98 is insufficient and the exhaust gas leaks. was there.

  Hereinafter, this point will be described in detail.

  In the two-stage turbo system 81, as described above, the high-pressure stage turbo 82 is small and the piping of the two-stage system is complicated. Therefore, if the engine load increases when the high-pressure stage turbo 82 is used, The inlet pressure (exhaust pressure) in the turbine 820 is very high compared to the single stage turbo system.

  The work of the turbine 820 is determined by the pressure ratio at the inlet / outlet of the turbine 820. Even if the pressure ratio is constant, if the back pressure at the turbine outlet increases, the pressure difference at the turbine inlet / outlet increases.

  As described above, the two-stage turbo system 81 has a problem that the pressure loss of the gas passage such as the exhaust pipe 86 is large due to complicated piping, and the pressure difference at the turbine inlet / outlet becomes large when the high-pressure turbo 82 is used.

  When the high exhaust pressure acts on the high-pressure stage wastegate valve main body 93 and the exhaust gas switching valve main body, there arises a problem that the valve main bodies 93 are easily opened due to the pressure difference between the front and rear.

  For example, in the wastegate valve device 823 that drives the actuator 96 using the spring 98 and the supercharging pressure as shown in FIG. 10, the wastegate valve body 93 does not open against high exhaust pressure. It is important to increase the setting force of the spring 98 that fully closes the wastegate valve main body 93. For this reason, the actuator 96 is increased in size and becomes the largest neck for vehicle mounting.

  When the valve main body is driven using an electric actuator, since the motor is installed near the exhaust pipe 86, the durability of the motor is significantly reduced due to heat damage.

  Furthermore, the difference in thermal expansion between the drive shaft 95 installed outside and the exhaust manifold 85 or the turbine casing 91 that is a passage of high-temperature exhaust gas acts in a direction that weakens the biasing force of the spring 98 in the actuator 96.

  As described above, when the waste gate valve body 93 is opened by high exhaust pressure due to insufficient sealing force of the waste gate valve body 93, the exhaust leaks and the rotational speed of the turbine 820 decreases. As a result, the supercharging pressure is reduced, and soot in the exhaust gas is increased and engine fuel consumption is deteriorated.

  Therefore, an object of the present invention is to provide a valve device that can solve the above-described problems and improve the sealing force when the valve is closed.

  In order to achieve the above object, the present invention opens and closes an exhaust gas bypass passage for exhausting exhaust gas upstream of the turbine downstream to bypass the turbine provided in the exhaust passage of the engine with a supercharger. A valve body that opens and closes the exhaust gas bypass passage, an actuator that drives the valve body via a drive shaft, and the drive shaft for extending the drive shaft beyond a normal length. An incompressible fluid pressure cylinder device is provided, and pressure adjusting means for adjusting the internal pressure is connected to the incompressible fluid pressure cylinder device, and the drive shaft is held at the normal length by the pressure adjusting means. A valve operating mode that allows the actuator to open and close the valve body, and the pressure adjusting means extends the drive shaft beyond the normal length. The actuator can be switched to a valve closing mode in which the valve body is held in a closed state while taking a reaction force on the actuator side, and a supercharging pressure detecting means for detecting the supercharging pressure of the supercharger is provided. The control means for controlling the pressure adjusting means based on the supercharging pressure of the supercharging pressure detecting means is provided, and the control means is configured such that the supercharging pressure detected by the supercharging pressure detecting means is less than a predetermined pressure. At this time, the pressure adjusting means is instructed to switch to the valve closing mode, and the pressure adjusting means is instructed to switch to the valve operating mode when the pressure is higher than the predetermined pressure.

  In order to achieve the above object, the present invention relates to a valve device in which a drive shaft is reciprocated by an actuator to open and close a valve body connected to the drive shaft. An incompressible fluid pressure cylinder device for extending the length is provided, and a pressure adjusting means for adjusting the internal pressure is connected to the incompressible fluid pressure cylinder device, and the drive shaft is connected to the pressure adjusting means. The valve operating mode is maintained at the normal length and allows the valve body to be opened and closed by the actuator, and the drive shaft is extended beyond the normal length by the pressure adjusting means, and a reaction force is applied on the actuator side. On the other hand, the valve body can be switched to a valve closing mode for holding the valve body in a closed state.

  Preferably, the pressure adjusting means holds the internal pressure of the incompressible fluid pressure cylinder device at a normal pressure and holds the drive shaft at the normal length during the valve operation mode, and holds the drive shaft at the normal length. The pressure adjusting means applies a pressure higher than normal pressure to the incompressible fluid pressure cylinder device to hold the valve body in a closed state.

  Preferably, the pressure adjusting means opens and closes a pump that supplies the incompressible fluid to the incompressible fluid pressure cylinder device and a discharge path that discharges the incompressible fluid from the incompressible fluid pressure cylinder device. And a pressure regulating valve that is provided in the discharge passage and that maintains the internal pressure of the incompressible fluid pressure cylinder device at normal pressure when the discharge valve is opened.

  Preferably, the actuator includes a diaphragm to which the drive shaft is coupled, an actuator housing that movably accommodates the diaphragm, and a partition formed in the actuator housing to bias the diaphragm in a valve opening direction of the valve body. A pressure chamber into which the pressurized gas is introduced, and an elastic member that urges the diaphragm in the valve closing direction of the valve body.

  Preferably, a control means for controlling the pressure adjusting means is provided, and the valve body is disposed in an exhaust gas bypass passage communicating with an upstream side and a downstream side of a turbine provided in an exhaust passage of an engine with a supercharger. The intake air pressurized by the supercharger is introduced into the pressure chamber of the actuator, and the control means is connected to a supercharging pressure detecting means for detecting the supercharging pressure of the supercharger. When the supercharging pressure detected by the supercharging pressure detecting means is less than a predetermined pressure, the pressure adjusting means is instructed to switch to the valve closing mode, and when the supercharging pressure is higher than the predetermined pressure, the pressure adjusting means operates the valve. Instructs switching to the mode.

  According to this invention, the outstanding effect that the sealing force at the time of valve closing can be improved is exhibited.

  Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

  The valve device according to the present embodiment is applied to, for example, a wastegate valve device of a supercharged vehicle engine equipped with a two-stage turbo system or the like.

  First, the two-stage turbo system of this embodiment will be described based on FIG.

  As shown in FIG. 8, in the two-stage turbo system 81, a small high-pressure stage turbo 82 and a large low-pressure stage turbo 83 are arranged in series.

  An exhaust manifold 85 and an exhaust pipe 86 forming an exhaust passage are connected to the supercharged engine 84. In the exhaust pipe 86, a turbine 820 of the high-pressure stage turbo 82, an exhaust gas switching valve device 87, and a turbine 830 of the low-pressure stage turbo 83 are arranged in this order from the engine 84 side (upstream side). The exhaust gas switching valve device 87 is communicated with the exhaust manifold 85 by an exhaust gas switching valve pipe 88.

  In the intake pipe 89, a compressor 831 of the low-pressure stage turbo 83, a compressor 821 of the high-pressure stage turbo 82, and the intake air switching valve device 100 are arranged in this order from the upstream side. It is communicated with an intake pipe 89 between both compressors 821, 831.

  Further, an exhaust gas recirculation pipe (EGR pipe) 102 for circulating a part of the exhaust gas to the intake system is connected to the exhaust manifold 85, and an EGR cooler 103 is provided in the exhaust gas recirculation pipe 102.

  Here, the high-pressure stage turbo 82 and the low-pressure stage turbo 83 provided in the engine 84 are for exhausting exhaust gas upstream of the turbines 820 and 830 to the downstream side in order to bypass the turbines 820 and 830. Exhaust gas bypass passages 822 and 832 and waste gate valve devices 1 and 833 that open and close the exhaust gas bypass passages 822 and 832 are provided.

  As the wastegate valve device 1 of the high-pressure stage turbo 82, the valve device of this embodiment is used.

  Next, the valve device 1 of the present embodiment will be described with reference to FIGS.

  As shown in FIGS. 1 and 2, the valve device 1 according to the present embodiment is configured such that a drive shaft 3 is reciprocated by an actuator 2 to open and close a valve body 4 connected to the drive shaft 3. The drive shaft 3 is provided with an incompressible fluid pressure cylinder device (hereinafter referred to as a cylinder device) 5 for extending the drive shaft 3 beyond its normal length, and the cylinder device 5 is adjusted to adjust the internal pressure. The pressure adjusting means 6 is connected, the pressure adjusting means 6 holds the drive shaft 3 at the normal length, and allows the actuator 2 to open and close the valve body 4, and the pressure adjusting means. The drive shaft 3 is extended beyond the normal length by means 6 and can be switched to a valve closing mode in which the valve body 4 is held in a closed state while taking a reaction force on the actuator 2 side. It is.

  As will be described in detail later, the pressure adjusting means 6 maintains the internal pressure of the cylinder device 5 at the normal pressure during the valve operation mode to maintain the drive shaft 3 at the normal length, and the cylinder during the valve closing mode. A pressure higher than normal pressure is applied to the device 5 to keep the valve body 4 in a closed state.

  The actuator 2 of the present embodiment includes a diaphragm 21 to which the drive shaft 3 (actuator-side drive shaft 31 described later) is coupled, an actuator housing 22 that accommodates the diaphragm 21 so as to be movable in the vertical direction, and the actuator housing 22 And a pressure chamber 23 into which a pressurized gas is introduced to urge the diaphragm 21 in the valve opening direction (upward) of the valve body 4 and the diaphragm 21 in the valve closing direction (downward) of the valve body 4. And an elastic member 24 (a spring in the illustrated example).

  The spring 24 is formed in an annular shape and extends from the ceiling surface of the actuator housing 22 to the upper surface of the diaphragm 21.

  A stopper 211 is provided on the upper surface of the diaphragm 21, and the stopper 211 contacts the ceiling surface of the actuator housing 22 when the spring 24 is compressed. The stopper 211 of the present embodiment is set slightly higher (longer) than the close contact height (minimum compression length) of the spring 24. As will be described in detail later, in the valve closing mode, a high pressure is applied to the cylinder device 5 and the drive shaft 3 extends, but the maximum extension length of the drive shaft 3 is defined by the stopper 211, and the length of the drive shaft 3. Is kept constant.

  The actuator housing 22 is attached to the engine 84, and the pressure chamber 23 is defined by the surface of the engine 84, the inner surface of the actuator housing 22, and the lower surface of the diaphragm 21.

  The pressure chamber 23 is provided with an introduction path 231 for introducing intake air (pressurized gas) pressurized by a high-pressure stage turbo 82 (supercharger). The introduction path 231 communicates with an intake pipe 89 (see FIG. 8) on the downstream side of the compressor 821 of the high-pressure turbo 82, for example.

  In the valve operation mode, the actuator 2 basically urges the diaphragm 21 downward by the spring 24 to close the valve body 4, and the pressure of the intake air from the introduction path 231 is the urging force (setting force) of the spring 24. ), The diaphragm 21 is moved upward to raise the drive shaft 3 and open the valve body 4.

  The valve body 4 is disposed in an exhaust gas bypass passage 822 that communicates the upstream and downstream of the turbine 820 provided in the exhaust passage 86 of the supercharged engine 84.

  More specifically, the turbine 820 is accommodated in a turbine casing 824, and an exhaust gas introduction path 825 for introducing exhaust gas to the turbine 820 and an exhaust gas discharge path 826 for discharging exhaust gas are respectively provided in the turbine casing 824. It is formed.

  Further, an exhaust gas bypass passage 822 that bypasses the turbine 820 is formed in the turbine casing 824, and an inlet (bypass inlet) 827 of the exhaust gas bypass passage 822 is connected to the exhaust gas introduction passage 825, and an outlet (bypass outlet). 828 is connected to the exhaust gas discharge path 826. The valve body 4 is disposed at the bypass inlet 827.

  The valve body 4 is provided in the exhaust gas bypass passage 822 and is seated on the wall surface (seat surface) of the exhaust gas bypass passage 822 to close the bypass inlet 827 or rotate inwardly in the exhaust gas bypass passage 822. The bypass inlet 827 is opened. The valve body 4 is rotatably supported by an L-shaped link 41, and is connected to the drive shaft 3 (valve-side drive shaft 32) via the L-shaped link 41.

  The drive shaft 3 of this embodiment is formed to be extendable so that it can be set to a normal length in the valve operation mode and to a length exceeding the normal length in the valve closing mode.

  Here, the normal length means that the valve body 4 closes the exhaust gas bypass passage 822 when the actuator 2 is not operated (when the spring 24 is not compressed), and the valve body when the actuator 2 is operated (when the spring 24 is compressed). 4 is a length that opens the exhaust gas bypass passage 822.

  Specifically, the drive shaft 3 includes a valve-side drive shaft 32 connected to the valve body 4 via an L-shaped link 41, an actuator-side drive shaft 31 connected to the diaphragm 21 of the actuator 2, and the valve side It is comprised with the cylinder apparatus 5 which connects the drive shaft 32 and the actuator side drive shaft 31. FIG.

  As shown in FIG. 3, the cylinder device 5 is movable in an axial direction (vertical direction in FIG. 3) in a case 51 in which an incompressible fluid (lubricating oil in the illustrated example) is enclosed. And a piston 52 housed in the housing. The actuator side drive shaft 31 is fixed to the case 51 (screwed in the illustrated example), and the valve side drive shaft 32 is fixed to the piston 52.

  A screw hole 511 for screwing a screw portion 311 formed at one end of the actuator side drive shaft 31 is formed in the upper portion of the case 51. Further, a drive shaft length adjusting lock nut 53 is disposed above the case 51, and the actuator side drive shaft 31 is screwed into the screw hole 511 of the case 51 through the drive shaft length adjusting lock nut 53. Match. The protrusion length of the actuator side drive shaft 31 with respect to the case 51 is adjusted by the drive shaft length adjusting lock nut 53.

  An oil chamber 54 filled with oil is formed in the case 51 below the screw hole 511.

  Specifically, a hole 512 extending upward from the lower surface is formed in the lower portion of the case 51, and the hole 512 is fixed to the lower surface of the case 51 with a fixing screw (not shown). It is blocked by 513. A piston 52 is provided in the hole 512 so as to be slidable in the vertical direction, and the oil chamber 54 is defined by the upper surface of the piston 52 and the inner surface of the hole 512.

  An O-ring 521 for preventing oil leakage from the oil chamber 54 is attached to the outer periphery of the piston 52. The O-ring 521 of the present embodiment is provided at each of the upper end portion and the lower end portion of the piston 52. A valve-side drive shaft 32 is fixed to the lower surface of the piston 52, and the valve-side drive shaft 32 extends downward through the case lid 513.

  In addition, an oil passage 514 for supplying and discharging oil to and from the oil chamber 54 is formed in the case 51, and the pressure adjusting means 6 is connected to the oil passage 514.

  The pressure adjusting means 6 includes a pump 61 for supplying oil to the cylinder device 5, and discharges for opening and closing the discharge passages (hereinafter referred to as oil discharge passages) 514, 611 and 631 for discharging oil from the cylinder device 5. A solenoid valve 62 that forms a valve, and a pressure regulating valve 63 that is provided in an oil discharge passage 631 downstream from the solenoid valve 62 and holds the internal pressure of the cylinder device 5 at normal pressure when the solenoid valve 62 is opened. .

  The pump 61 has a discharge port connected to an oil passage 514 of the cylinder device 5 via a pump discharge pipe 611, and a suction port connected to a supply source such as an oil tank (not shown) via a pump suction pipe 612. The pump discharge pipe 611 is made of, for example, a high-pressure flexible hose so that the vertical movement of the cylinder device 5 can be followed when the valve device 1 is operated.

  A pressure regulating pipe 631 (upstream end) for discharging oil from the cylinder device 5 and reducing the hydraulic pressure is connected to the pump discharge pipe 611. The downstream end of the pressure regulating pipe 631 is connected to the pump suction pipe 612. The pressure adjusting pipe 631, the pump discharge pipe 611, and the oil passage 514 of the cylinder device 5 constitute the oil discharge passage.

An electromagnetic valve 62 and a pressure regulating valve 63 are arranged in the pressure regulating pipe 631 in order from the upstream side. The electromagnetic valve 62 is controlled to be opened and closed by the control means 7 described later. The pressure regulating valve 63 opens when the hydraulic pressure of the pressure regulating pipe 631 is equal to or higher than a predetermined set pressure, and closes when the pressure is less than the set pressure. In the present embodiment, the set pressure of the pressure regulating valve 63 is set to about 0.1 kg / cm ² . Therefore, when the electromagnetic valve 62 is opened, the oil chamber 54 of the cylinder device 5 is maintained at about 0.1 kg / cm ² . That is, the normal pressure in this embodiment refers to a pressure of about 0.1 kg / cm ² (approximately 0).

  The pressure adjusting means 6 is disposed in a safety pipe 641 that connects the pump discharge pipe 611 and the pump suction pipe 612, and is opened when the hydraulic pressure of the safety pipe 641 (oil chamber 54) exceeds a predetermined upper limit pressure. A safety valve (pressure regulating valve for preventing excessive hydraulic pressure) 64 is provided. In the present embodiment, the set pressure (predetermined upper limit pressure) of the safety valve 64 is set higher than the set pressure of the pressure regulating valve 63.

  In the present embodiment, a microcomputer 7 serving as a control means for controlling the pump 61 and the electromagnetic valve 62 of the pressure adjusting means 6 is provided. The microcomputer 7 is connected to the pump 61 and the electromagnetic valve 62 in order to communicate control signals (in the example shown in the figure, a pump ON-OFF signal and a solenoid valve ON-OFF signal). Further, the microcomputer 7 is connected to a supercharging pressure detection means for detecting the supercharging pressure of the high-pressure stage turbo (supercharger) 82. The supercharging pressure detection means is constituted by, for example, a supercharging pressure sensor 71 arranged in an intake pipe 89 downstream of the compressor 821 of the high-pressure turbo 82, and a supercharging pressure signal is output from the supercharging pressure sensor 71. Input to the microcomputer 7.

  When the supercharging pressure detected by the supercharging pressure sensor 71 is less than a predetermined wastegate valve opening set pressure (predetermined pressure), the microcomputer 7 instructs the pressure adjusting means 6 to switch to the valve closing mode. When the supercharging pressure is equal to or higher than the wastegate valve opening set pressure, the pressure adjusting means 6 is instructed to switch to the valve operating mode. The wastegate valve opening set pressure is set, for example, to a pressure at which the actuator 2 starts to operate (a pressure corresponding to a set force of the spring 24 (hereinafter referred to as a set pressure)).

  Next, the operation of the valve device 1 according to the present embodiment will be described with reference to FIGS.

  First, the assembly of the valve device 1 will be described with reference to FIG.

  As shown in FIG. 5, when the valve device 1 is assembled, first, the oil pump 61 is operated to apply hydraulic pressure to the oil chamber 54 of the cylinder device 5 to extend the drive shaft 3 (cylinder device 5). At this time, the hydraulic pressure is higher than the set pressure of the spring 24 of the actuator 2.

  Due to the hydraulic pressure, the actuator side drive shaft 31 screwed into the case 51 moves upward while contracting the spring 24 of the actuator 2, and stops when the stopper 211 hits the ceiling surface of the actuator housing 22. On the other hand, the valve-side drive shaft 32 fixed to the piston 52 in the case 51 moves while being pressed downward, and stops when the valve body 4 hits the seating surface of the bypass inlet 827.

  With the valve body 4 thus blocking the bypass inlet 827 and the extension of the cylinder device 5 being restricted by the stopper 211, the actuator side drive shaft 31 is fixed by the drive shaft length adjusting lock nut 53, The length of the drive shaft 3 in the valve closing mode (hereinafter referred to as the closing length) is determined.

  Next, the valve operation mode and the valve closing mode will be described with reference to FIGS.

  As shown in FIG. 5, in the valve closing mode, a hydraulic pressure higher than normal pressure (hereinafter referred to as a closing pressure) is applied to the oil chamber 54 of the cylinder device 5. The closing pressure is set higher than the set pressure of the spring 24 of the actuator 2 as in the above-described assembly.

  The drive shaft 3 is extended to the closing length determined at the time of assembly by the closing pressure. Specifically, the actuator side drive shaft 31 is regulated by the stopper 211, and the valve side drive shaft 32 is pressed downward by the cylinder device 5 to which a reaction force is applied by the stopper 211. By the cylinder device 5, the valve body 4 is pressed against the seating surface of the bypass inlet 827 and is held in the closed state.

  In the valve closing state, the hydraulic pressure (closing pressure) of the cylinder device 5 is set higher than the set pressure of the spring 24, so that the valve body 4 is sealed with a stronger sealing force than the spring 24.

  As shown in FIG. 6, in the valve operation mode, the valve side drive shaft 32 is inserted into the case 51, and the drive shaft 3 has a normal length. In the actuator 2, the spring 24 is restored to its original length. Furthermore, the hydraulic pressure in the oil chamber 54 is maintained at normal pressure, the expansion and contraction of the cylinder device 5 is restricted, and the drive shaft 3 is maintained at the normal length.

  As shown in FIG. 7, in this valve operation mode, the valve device 1 works in the same manner as a normal wastegate valve device that operates at a supercharging pressure, and the valve body 4 is balanced by the spring 24 and the supercharging pressure. Opened and closed.

  Next, an example of the action | operation of the valve apparatus 1 of this embodiment is demonstrated based on the flowchart of FIG. This flowchart is executed by the microcomputer 7 after the engine 84 is started.

  When the key switch is turned on in step S1, the engine 84 is started, and then predetermined initialization (initial processing) is performed in step S2.

  Next, in step S3, the microcomputer 7 drives and rotates the pump 61. Next, in step S4, the microcomputer 7 closes the electromagnetic valve 62. At this time, the solenoid valve 62 is closed with a delay of 0.1 to 0.2 seconds after the pump 61 starts operating.

  By this step S3 and step S4, the cylinder device 5 is in a state where hydraulic pressure is applied, and the actuator side drive shaft 31 is pressed upward and the valve side drive shaft 32 is pressed downward until the assembly state. Since the oil inside the cylinder device 5 is incompressible, the bypass inlet 827 is completely sealed by the valve body 4 even if excessive exhaust pressure acts on the valve body 4 in the valve opening direction.

  Furthermore, even if a difference in thermal expansion occurs between the engine exhaust system and the drive shaft 3 and the link 41 provided outside, the length of the drive shaft 3 is adjusted by the hydraulic pressure of the cylinder device 5, so that the sealing force is It does not decline.

  Next, in step S <b> 5, the supercharging pressure Pe is measured by the supercharging pressure sensor 71, and the measured supercharging pressure Pe is input to the microcomputer 7. In step S6, the microcomputer 7 determines whether or not the boost pressure Pe of the boost pressure sensor 71 is equal to or higher than the waste gate valve opening set pressure P0.

  When it is determined in step S6 that the supercharging pressure Pe is equal to or higher than the waste gate valve opening set pressure P0 (Pe> = P0), the microcomputer 7 switches the valve device 1 to the valve operation mode in steps S7 and S8.

  That is, the microcomputer 7 opens the electromagnetic valve 62 for a short time (0.1 to 0.2 seconds) in step S7, and stops the pump 61 in step S8.

  The valve opening time of the electromagnetic valve 62 is set by experimentally determining the time during which the actuator-side drive shaft 31 moves with the restoring force of the spring 24 (the time during which the spring 24 is restored to its original length).

  By this step S7 and step S8, the oil passage 514 is opened and the hydraulic pressure in the oil chamber 54 is lowered.

  As the hydraulic pressure decreases, the actuator-side drive shaft 31 moves downward by the restoring force of the spring 24. Further, the piston 52 moves upward and the valve side drive shaft 32 is inserted into the case 51.

  As a result, the drive shaft 3 contracts to the normal length described above.

  Further, the hydraulic pressure in the oil chamber 54 is adjusted to normal pressure (approximately 0 (positive pressure)) by the pressure regulating valve 63 provided downstream of the electromagnetic valve 62. When the solenoid valve 62 is closed in the normal pressure state, the oil is sealed in the oil chamber 54 and the oil passage 514, and even if an upward force is applied to the valve side drive shaft 32, the oil is out of the system. Access to and from is blocked. Of course, the pump 61 is provided with a check valve.

  Since the oil sealed in the oil chamber 54 and the oil passage 514 has incompressibility, the length of the drive shaft 3 does not change if the hydraulic pressure remains even a little. That is, as long as the oil in the oil chamber 54 and the oil passage 514 is not replaced with a compressible gas (air, gas, etc.), the drive shaft 3 maintains the length at Pe = P0 (normal length) and extends or There is no shrinkage.

  As a result, in step S9, the valve device 1 operates as a normal wastegate valve device. That is, since the drive shaft length (that is, the normal length) determined in step S7 and step S8 is maintained, the valve device 1 functions as a normal wastegate valve device.

  For example, when the supercharging pressure in the pressure chamber 23 exceeds the set pressure (set force) of the spring 24, the valve body 4 opens, and the exhaust gas leaks (discharges) from the upstream of the turbine 820 to the exhaust gas bypass passage 822. Thus, the rotational speed of the turbine 820 (and the compressor 821) is suppressed. Thus, the supercharging pressure is kept constant by the valve device 1 operating as a wastegate valve device.

  After step S9, the process returns to step S5 again and the supercharging pressure Pe is measured.

  Thereafter, when the supercharging pressure decreases and it is determined in step S6 that the supercharging pressure Pe is less than the waste gate valve opening set pressure P0 (Pe <P0), the process returns to step S3, and the microcomputer 7 drives the pump 61 drive signal. The valve closing signal of the electromagnetic valve 62 is transmitted respectively (step S3 and step S4), and the valve device 1 is switched to the valve closing mode.

  Thus, in this embodiment, the sealing force at the time of valve closing can be improved by hold | maintaining the valve main body 4 in a valve closing state with the pressure (hydraulic pressure) of an incompressible fluid.

  That is, a valve that seals high exhaust pressure by providing a cylinder device 5 that presses the drive shaft 3 in one direction (opposite to the exhaust pressure) via an incompressible fluid at an intermediate portion of the drive shaft 3 of the actuator 2 A mechanism can be realized.

  Further, in the valve operation mode, the length of the drive shaft 3 is maintained at the normal length, so that the function as the spring type actuator 2 is not impaired.

  In the present embodiment, since the sealing force is improved by the cylinder device 5, a high exhaust pressure can be sealed without increasing the size of the spring 24 of the actuator 2, and a strong sealing force can be obtained even with the small actuator 2. Obtainable.

  As a result, the vehicle mountability of the valve device can be improved.

  In the engine 84 in which the piping is complicated and the turbine outlet pressure is high, such as the two-stage turbo system 81 of this embodiment, or in the engine that is used in a state where the turbine outlet pressure is high by installing the post-processing device, even the small actuator 2 can achieve perfect exhaust System (waist gate valve device) can be sealed, and low emission and low fuel consumption can be realized.

  In addition, this invention is not limited to the above-mentioned embodiment, Various modifications and application examples can be considered.

  For example, the valve device of the present invention may be applied to the exhaust gas switching valve device 87 of FIG.

  Further, the incompressible fluid is not limited to lubricating oil.

  Further, the spring of the actuator may be used as a stopper. That is, in the valve closing mode, the extension of the drive shaft may be defined by compressing the spring until it fully contacts (to the limit).

FIG. 1 is a front view of a valve device according to an embodiment of the present invention. FIG. 2 is a view in the direction of the arrow II in FIG. FIG. 3 is an enlarged view of part III in FIG. FIG. 4 is a flowchart for explaining the operation of the valve device of the present embodiment. FIG. 5 is a diagram of the valve device of the present embodiment, showing a valve closing mode. FIG. 6 is a diagram of the valve device of the present embodiment and shows a valve operation mode. FIG. 7 is a diagram of the valve device of the present embodiment, showing the valve operation mode. FIG. 8 is a schematic model diagram of a 2-turbo system. FIG. 9 is a diagram for explaining the operation of the two-turbo system. FIG. 10 is a front view of a conventional valve device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Valve apparatus 2 Actuator 3 Drive shaft 4 Valve body 5 Incompressible fluid pressure cylinder apparatus 6 Pressure adjusting means

Claims (6)

In a valve device for opening and closing an exhaust gas bypass passage for discharging exhaust gas upstream of the turbine to the downstream side in order to bypass the turbine provided in the exhaust passage of the engine with a supercharger,
An incompressible fluid pressure for providing a valve body for opening and closing the exhaust gas bypass passage, an actuator for driving the valve body via a drive shaft, and extending the drive shaft beyond a normal length on the drive shaft. A cylinder device is provided, and pressure adjusting means for adjusting the internal pressure is connected to the incompressible fluid pressure cylinder device,
The drive shaft is held at the normal length by the pressure adjusting means, the valve operating mode is allowed to open and close the valve body by the actuator, and the drive shaft is extended from the normal length by the pressure adjusting means. And configured to be switchable to a valve closing mode for holding the valve body in a closed state while taking a reaction force on the actuator side,
A supercharging pressure detecting means for detecting the supercharging pressure of the supercharger is provided, and a control means for controlling the pressure adjusting means based on the supercharging pressure of the supercharging pressure detecting means is provided. When the supercharging pressure detected by the supercharging pressure detecting means is less than a predetermined pressure, the pressure adjusting means is instructed to switch to the valve closing mode, and when the supercharging pressure is higher than the predetermined pressure, the pressure adjusting means is operated by the valve. A valve device characterized by instructing switching to a mode. In a valve device in which a drive shaft is reciprocated by an actuator to open and close a valve body connected to the drive shaft,
The drive shaft is provided with an incompressible fluid pressure cylinder device for extending the drive shaft from the normal length, and a pressure adjusting means for adjusting the internal pressure is connected to the incompressible fluid pressure cylinder device,
The drive shaft is held at the normal length by the pressure adjusting means, the valve operating mode is allowed to open and close the valve body by the actuator, and the drive shaft is extended from the normal length by the pressure adjusting means. And a valve device configured to be switchable to a valve closing mode in which the valve body is held in a closed state while taking a reaction force on the actuator side.   The pressure adjusting means maintains the internal pressure of the incompressible fluid pressure cylinder device at a normal pressure during the valve operation mode, maintains the drive shaft at the normal length, and performs the pressure adjustment during the valve closing mode. The valve device according to claim 2, wherein the adjusting means applies a pressure higher than normal pressure to the incompressible fluid pressure cylinder device to hold the valve body in a closed state.   The pressure adjusting means includes a pump for supplying an incompressible fluid to the incompressible fluid pressure cylinder device, and a discharge valve for opening and closing a discharge path for discharging the incompressible fluid from the incompressible fluid pressure cylinder device. 4. The valve device according to claim 2, further comprising: a pressure regulating valve provided in the discharge passage and configured to maintain an internal pressure of the incompressible fluid pressure cylinder device at a normal pressure when the discharge valve is opened.   The actuator includes a diaphragm to which the drive shaft is coupled, an actuator housing that movably accommodates the diaphragm, and a pressurization that is formed in the actuator housing and biases the diaphragm in the valve opening direction of the valve body. 5. The valve device according to claim 2, further comprising: a pressure chamber into which gas is introduced; and an elastic member that urges the diaphragm in a valve closing direction of the valve body. Control means for controlling the pressure adjusting means is provided,
The valve body is disposed in an exhaust gas bypass passage communicating with an upstream and a downstream of a turbine provided in an exhaust passage of an engine with a supercharger,
The intake air pressurized by the supercharger is introduced into the pressure chamber of the actuator,
The control means is connected to a supercharging pressure detecting means for detecting a supercharging pressure of the supercharger, and the pressure adjustment is performed when the supercharging pressure detected by the supercharging pressure detecting means is less than a predetermined pressure. 6. The valve device according to claim 5, wherein a switching device is instructed to switch to the valve closing mode, and the pressure adjusting device is instructed to switch to the valve operating mode when the pressure is equal to or higher than the predetermined pressure.

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