JP5020339B2 - Variable valve operating device for internal combustion engine - Google Patents

Description

  The present invention includes an operating angle changing mechanism that changes the operating angle (size) of the intake valve, and a phase changing mechanism that changes the center phase (valve timing) of the operating angle of the intake valve with respect to the phase of the crankshaft. The present invention relates to a variable valve operating apparatus for an internal combustion engine.

  In the field of internal combustion engines, the intake valve operating angle (and valve lift amount) can be continuously changed in order to highly control the valve lift characteristics of the intake valves according to engine operating conditions and to obtain optimal operating characteristics. There has been proposed a variable valve operating apparatus that uses a combination of an operating angle changing mechanism and a phase changing mechanism capable of continuously changing the center phase of the operating angle.

  When such a variable valve system is used, the operating angle change range by the operating angle changing mechanism and the center by the phase changing mechanism are increased in order to increase the degree of freedom in setting the operating angle and the center phase and to cope with a wide range of operating conditions. I want to keep the phase change range as large as possible. In addition, we want to drive each change mechanism independently.

  However, if the change range is increased in this way, the intake valve and the piston may interfere in the vicinity of the exhaust top dead center. Specifically, when the operating angle of the intake valve is large, the central phase is greatly advanced, or when the central phase is greatly advanced, the operating angle is excessively increased. If the large operating angle and the advanced angle are performed at the same time, the intake valve and the piston may interfere with each other.

  In order to avoid such interference between the intake valve and the piston, practically, a control map or the like is set in advance so that the large operating angle and the advanced angle are not performed at the same time. However, there is still a possibility that the intake valve and the piston come into contact when the control fails. In order to eliminate the possibility of such contact between the intake valve and the piston, if the initial change range by both the change mechanisms is set narrow in advance, the degree of freedom in setting the valve lift characteristics of the intake valve is reduced, and The operating characteristics of the period cannot be obtained.

  The present invention has been made in view of such problems, and completely (mechanically) avoids interference between the intake valve and the piston without narrowing the initial change range of the operating angle changing mechanism and the phase changing mechanism. One purpose is to do.

  The variable valve operating apparatus for an internal combustion engine according to the present invention includes an operating angle changing mechanism for changing an operating angle (and / or valve lift amount) of an intake valve, and a center phase of the operating angle of the intake valve (rotation of a crankshaft). And a phase change mechanism that changes the phase). Each change mechanism is preferably changeable continuously within a preset initial change range. Examples of the phase changing mechanism include a type using a planetary gear or a type using a vane in addition to a type using a helical gear as in the embodiments described later.

  Then, mechanically interlocking with the operation of the phase change mechanism, and when the advancement degree of the center phase is large, an operation angle restricting body that restricts the expansion of the operation angle, and the operation of the operation angle change mechanism And at least one of the phase restricting body for restricting the advance angle of the center phase when the operating angle is large, preferably both.

  By providing such a restricting body, the possibility of interference between the intake valve and the piston can be ensured even during a control failure without setting the initial change range of the operating angle and center phase by each change mechanism in advance. Can be eliminated. Therefore, reliability can be improved without sacrificing the degree of freedom in setting the valve lift characteristics.

  Typically, an operating angle control shaft extending substantially parallel to a drive shaft that rotates in conjunction with the crankshaft, and a phase control slider that can slide along the drive shaft, the operating angle control shaft being The operating angle is changed by turning, and the center phase is changed by sliding the phase control slider.

  The rotation range of the phase restricting body is limited by the operating angle restricting body that slides integrally with the phase control slider, and the phase restricting body that rotates integrally with the operating angle control shaft The slide range of the operating angle restricting body is limited. That is, it is configured to restrict the operations of the two restrictors with a simple structure using the operation of the operation angle control shaft and the phase control slider accompanying the change of the operation angle and phase.

The working angle changing mechanism preferably includes a driving eccentric cam provided eccentrically to the drive shaft, a first link rotatably fitted on the eccentric drive cam, is provided eccentrically to the operating angle control shaft A control cam, a rocker arm that is rotatably fitted to the control cam and has one end connected to the first link, and a swing that is swingably provided on the drive shaft and drives the intake valve. A cam, and a second link connected to the other end of the rocker arm and the swing cam.

  The operating angle changing mechanism configured as described above has a swing cam that presses the intake valve disposed coaxially with the drive shaft, so there is no risk of shaft misalignment between the swing cam and the drive shaft. In addition to being excellent in accuracy, the link elements such as the first and second links and the rocker arm are gathered around the drive shaft, and the mechanism can be made compact. Also, since many of the connecting parts between the members are in surface contact, such as the bearing part of the drive eccentric cam and the first link and the bearing part of the control cam and the rocker arm, it is easy to lubricate and durable. Excellent in reliability and reliability. Furthermore, when applied to a general internal combustion engine using a fixed cam and a camshaft, the swing cam and the drive shaft may be arranged at the positions of the fixed cam and the camshaft, and the layout changes are very much. Since it is less, it can be easily applied to existing internal combustion engines. And since the operating angle and valve lift amount of the intake valve or exhaust valve can be continuously adjusted to any size according to the engine operating state, the degree of freedom of setting is high, fuel consumption, output etc. according to the engine operating situation The driving performance can be improved efficiently.

  The phase change mechanism preferably includes an outer peripheral gear that rotates in synchronization with the crankshaft, an inner peripheral gear that is coaxially disposed inside the outer peripheral gear and rotates integrally with the drive shaft, and the phase. A substantially cylindrical helical gear that is provided on the control slider and meshes with both the outer peripheral gear and the inner peripheral gear.

  Therefore, when the outer peripheral gear rotates in synchronization with the crankshaft, the inner peripheral gear and the drive shaft rotate via the helical gear. In addition, by sliding the phase control slider along the drive shaft according to the engine operating state, the outer peripheral gear and the inner peripheral gear meshing with the helical gear rotate relatively, and the phase of the drive shaft with respect to the crankshaft is changed. As a result, the center phase of the operating angle of the intake valve changes.

  Such a phase change mechanism is a relatively simple structure in which a helical gear or the like is provided at one end of the drive shaft, can be easily applied to an existing engine, and the center phase of the operating angle of the intake valve is set. Since it can be changed continuously, the degree of freedom of setting is also high.

  More specifically, the operating angle restricting body is a stopper that is slidably fitted on the outer periphery of the drive shaft, and the phase restricting body is fixed or integrally formed on the outer periphery of the control shaft. It is a fan-shaped arm, and the stopper and the arm can advance into the mutual movement range. In this case, the movement range of both can be mutually limited with a simple structure mainly composed of a stopper and an arm.

  According to the present invention, it is possible to reliably eliminate the possibility of interference between the intake valve and the piston even at the time of a control failure or the like without setting the initial change range of the operating angle and the center phase by each changing mechanism in advance. it can. Therefore, reliability can be improved without sacrificing the degree of freedom in setting the valve lift characteristics.

1 is a schematic configuration diagram showing a variable valve operating apparatus for an internal combustion engine according to an embodiment of the present invention. The characteristic view showing the opening and closing timing of the intake valve according to engine operating conditions. Action | operation explanatory drawing of the said variable valve apparatus. Similarly explanatory drawing of an effect | action of a variable valve apparatus. The characteristic view which shows the change range of the operating angle and center phase of an intake valve which concerns on this embodiment.

  FIG. 1 is a schematic configuration diagram showing a variable valve operating apparatus for an internal combustion engine according to an embodiment of the present invention. This variable valve operating device mainly cranks the operating angle changing mechanism 10 that continuously changes the operating angle of the intake valve 1 and the amount of valve lift, and the center phase (valve timing) of the operating angle of the intake valve 1. And a phase changing mechanism 20 that changes the phase of the shaft.

  First, the configuration of the operating angle changing mechanism 10 will be described. Above the intake valve 1, a drive shaft 11 and an operating angle control shaft 12 extending in the cylinder row direction parallel to each other are connected to the cylinder head 2 (see FIGS. 3 and 4). It is rotatably supported. The drive shaft 11 is rotationally driven around the shaft by rotational power transmitted from a crankshaft (not shown) via a phase changing mechanism 20 described later. A rocking cam 13 that abuts on and presses the valve lifter 1 a of each intake valve 1 is rotatably fitted to the drive shaft 11, and a drive eccentric cam 14 that is eccentric with respect to the drive shaft 11. Is fixed for each cylinder, and a ring-shaped first link 15 is rotatably fitted around the outer periphery of the drive eccentric cam 14. A control cam 16 is eccentrically fixed to the operating angle control shaft 12 for each cylinder, and a rocker arm 17 is rotatably fitted on the outer periphery of the control cam 16. One end of the rocker arm 17 is connected to the tip of the first link 15, and the other end of the rocker arm 17 is connected to one end of the rod-shaped second link 18. The other end of the second link 18 is connected to the tip of the swing cam 13.

  With this configuration, when the drive shaft 11 rotates in conjunction with the crankshaft, the first link 15 substantially translates via the drive eccentric cam 14, and the rocker arm 17 connected to the first link 15 is controlled by the control cam. The swing cam 13 swings around the second link 18. In response to the swinging motion of the swing cam 13, the valve lifter 1a of the intake valve 1 is pressed, and the intake valve 1 opens and closes.

  Further, when the operating angle control shaft 12 is rotated according to the engine operating state, the position of the control cam 16 serving as the rocking center of the rocker arm 17 is changed, and the postures of the rocker arm 17 and the links 15 and 18 are changed. . As a result, the swing range and phase of the swing cam 13 change, and mainly the size of the operating angle of the intake valve 1 and the valve lift amount change.

  In the operating angle changing mechanism 10 having such a configuration, the swing cam 13 that presses the valve lifter 1 a of the intake valve 1 is disposed coaxially with the drive shaft 11. There is no possibility of misalignment and the like, and the control accuracy is excellent, and the link elements 15, 17, and 18 are gathered around the drive shaft 11, so that the mechanism can be made compact. Also, since many of the connecting portions between the members are in surface contact, such as the bearing portion of the drive eccentric cam 14 and the first link 15 and the bearing portion of the control cam 16 and the rocker arm 17, lubrication is achieved. It is easy to perform and has excellent durability and reliability.

  Further, when applied to a general internal combustion engine using a fixed cam and a camshaft, the swing cam 13 and the drive shaft 11 may be disposed at the positions of the fixed cam and the camshaft, which greatly changes the layout. Therefore, it can be easily applied to existing internal combustion engines.

  And since the operating angle and valve lift amount of the intake valve 1 can be continuously adjusted to an arbitrary magnitude according to the engine operating state, the degree of freedom of setting is high, and the fuel consumption, output, etc. according to the engine operating situation The performance can be improved effectively.

  3A and 4A show a phase change mechanism 20 using a helical gear 21. FIG. The sprocket 22 receives rotational power from a crankshaft via a chain or a timing belt (not shown) and rotates in synchronization with the crankshaft. An outer peripheral gear 23 is integrally formed on the inner peripheral side of the sprocket 22. Is formed. On the other hand, a cylindrical inner peripheral gear 24 is integrally fixed to one end portion of the drive shaft 11. The inner peripheral gear 24 is coaxially disposed inside the outer peripheral gear 23. . The helical gear 21 has a substantially cylindrical shape that meshes with both the outer peripheral gear 23 and the inner peripheral gear 24.

  With such a configuration, when the sprocket 22 rotates in synchronization with the crankshaft, this rotational power is transmitted to the drive shaft 11 via the outer peripheral gear 23, the helical gear 21, and the inner peripheral gear 24. Is driven to rotate.

  A hydraulic chamber 25 faces one end surface of the helical gear 21 in the axial direction. When the hydraulic pressure in the hydraulic chamber 25 exceeds a predetermined value, the helical gear 21 is driven against the urging force of the return spring 26. Slide along the axis 11 in the axial direction. That is, the helical gear 21 slides along the drive shaft 11 by switching and controlling the hydraulic pressure in the hydraulic chamber 25 according to the engine operating state. As a result, the inner peripheral gear 24 and the outer peripheral gear 23 meshing with the helical gear 21 rotate relatively, the phase of the drive shaft 11 with respect to the crankshaft changes, and the center phase of the operating angle of the intake valve 1 changes. .

  Such a phase changing mechanism 20 has a relatively simple structure in which a helical gear or the like is provided between the sprocket 22 and one end portion of the drive shaft 11, can be easily applied to an existing engine, and has an intake air Since the center phase of the operating angle of the valve 1 can be continuously changed, the degree of freedom of setting is also high.

  Referring to FIG. 1 again, one end of the operating angle control shaft 12 is connected to an operating angle actuator 31 that rotates and holds the control shaft 12 within a predetermined control range. The actuator 31 is a hydraulic actuator that operates according to the supplied hydraulic pressure, and the hydraulic pressure supplied to the actuator 31 is switched and adjusted by an operating angle hydraulic device 33 including a hydraulic control valve and the like. On the other hand, the phase changing mechanism 20 has a function as a hydraulic actuator that slides the helical gear 21 (phase control slider) in accordance with the hydraulic pressure supplied to the hydraulic chamber 25. The hydraulic pressure supplied to the hydraulic chamber 25 is It is switched and adjusted by a phase hydraulic device 34 equipped with a hydraulic control valve and the like.

  The ECU (engine control unit) 35 performs general engine control such as fuel injection control based on the valve lift amount, load, engine speed, oil temperature, etc. detected or estimated by various sensors, as well as hydraulic pressure. Control signals are output to the devices 33 and 34 to control the operations of the hydraulic devices 33 and 34.

  FIG. 2 shows a preferable setting example of the specific intake valve opening / closing timing in each operating condition, and φ in the figure represents the center phase of the operating angle of the intake valve. This setting content is stored in advance in the memory of the ECU 35 in the form of a control map, for example.

  In the idle range, IVC (intake valve closing timing) is set near the bottom dead center, the actual compression ratio is increased, combustion is stabilized, and lVC (intake valve opening timing) is delayed from the top dead center. By doing so, the flow velocity of the intake air is increased. As a result, it is possible to remarkably improve the combustion responsibility and combustion stability during idling. Specifically, the center phase φ is set to the (maximum) retardation phase, and the intake operation angle is set to the (maximum) small operation angle.

  In the R / L region (steady travel region), in order to reduce the pumping loss, the central phase φ is advanced to make lVO almost the top dead center, and IVC is advanced to reduce the actual suction stroke. That is, the center phase φ is mainly advanced as compared with the above-described idle region.

  In the acceleration region, the central phase φ is further advanced as compared with the R / L region, and the operating angle is slightly increased, so that the lVO is advanced before the top dead center, and the residual gas is mixed with the air-fuel mixture. In order to further improve fuel efficiency.

  In the fully open range, the setting is slightly different between low speed and high speed.However, the center phase φ is retarded and the operating angle is increased with the increase in the rotational speed, and the maximum output is mainly achieved. We are trying to improve.

  As shown in FIG. 2, in the control content set in advance, for example, in the fully open region, the center phase φ is retarded as the operating angle increases, and the operating angle and the advance amount of the center phase are the same. It doesn't get too big in time. Therefore, as long as the control is performed well, there is no possibility that the intake valve 1 and the piston interfere with each other.

  However, if the operating angle and the advance amount of the center phase become excessively large at the same time, such as during a control failure, there is a possibility that the intake valve 1 and the piston interfere with each other. In order to completely eliminate the possibility of such interference, in the present embodiment, as shown in FIGS. 3 to 5, mechanically interlocked with the operation of the phase changing mechanism 20 and the advance angle of the center phase is predetermined. When it is larger than the phase P3, mechanically interlocking with the operation of the stopper 41 as an operating angle restricting body for mechanically prohibiting and restricting the operating angle from exceeding the predetermined value Q3 and the operation of the operating angle changing mechanism 10 And an arm 42 as a phase restricting body for restricting the advance angle exceeding the predetermined phase P3 of the center phase when the operating angle is larger than the predetermined value Q3.

  The arm 42 is fixed to or integrally formed with the operating angle control shaft 12, and rotates integrally with the operating angle control shaft 12. The arm 42 has a predetermined thickness projecting radially from the outer periphery of the operating angle control shaft 12. It has a fan-like shape.

  The stopper 41 is slidably fitted on the outer periphery of the drive shaft 11 and constitutes a part of the phase control slider 43 that slides along the drive shaft 11 integrally with the helical gear 21 described above. That is, the phase control slider 43 is fixed to one end of the collar 44 with the fixing bolt 45 and the fixing pin 45 to one end of the helical gear 21. A joint 47 fixed at 46, and a connecting pin 49 that is fixed to the other end of the collar 44 by a fixing bolt 48 and that fits into the inner peripheral recess of the stopper 41.

  The stopper 41 is formed with a positioning recess 41 a that can be fitted into the radial positioning projection 3 provided on the cylinder head 2, and a step 41 b that restricts the rotation range of the arm 42. The fixing bolts 45 and 48 and the collar 44 are formed in a hollow shape so as to secure an oil passage to the hydraulic chamber 25. Further, the radial hole 11a of the drive shaft 11 through which the connecting pin 49 is inserted in the radial direction is also extended in the axial direction so as to allow the connecting pin 49 to move in the axial direction. The collar 44 rotates together with the helical gear 21, but the connecting pin 49 is connected to the collar 44 so as to be relatively rotatable.

  Next, with reference to FIGS. 3-5, the effect | action and effect of this embodiment are explained in full detail. When the phase control slider 43 slides to the left in FIGS. 3 and 4A, the center phase of the operating angle of the intake valve 1 is advanced, and the operating angle control shaft 12 and the arm 42 are moved in FIGS. It is set so that the operating angle of the intake valve is increased when it rotates in the clockwise direction B). In the advanced state in which the center phase of the operating angle of the intake valve 1 is advanced from the predetermined phase P3 (see FIG. 5), the step portion 41b of the stopper 41 has the arm 42 as shown in FIG. The stopper 41 limits the rotation range of the arm 42 and the operating angle control shaft 12 to the large operating angle side (clockwise direction). As a result, the range in which the operating angle can be changed by the operating angle changing mechanism 10 is limited from the minimum operating angle Q1 to the predetermined value Q3, and the expansion beyond the predetermined value Q3 is mechanically prohibited or restricted.

  On the other hand, in the retarded state where the center phase is retarded from the predetermined phase P3, as shown in FIG. 4A, the stepped portion 41b of the stopper 41 is moved to the right side of the rotation range of the arm 42. The stopper 41 does not restrict the rotation range of the arm 42. Accordingly, the operating angle changing mechanism 10 can change the operating angle of the intake valve over the entire range from the minimum operating angle Q1 to the maximum operating angle Q2.

  When the operating angle of the intake valve 1 is larger than the predetermined value Q3, a part of the arm 42 enters the sliding range of the stopper 41 as shown in FIG. The sliding movement of the stopper 41 in the direction of increasing the operating angle (the left direction in the figure) is mechanically prohibited or restricted until the end surface of the stopper 41 comes into contact with the arm 42. Therefore, in such a large operating angle state, the slide range of the phase control slider 43 including the stopper 41 is limited by the arm 42, and the changeable range of the center phase is limited from the most retarded phase P1 to the predetermined phase P3. Then, the advance angle of the center phase exceeding the predetermined phase P3 is mechanically prohibited or regulated.

  On the other hand, in a state where the operating angle is a small operating angle smaller than the predetermined value Q3, the arm 42 is retracted to a position outside the sliding range of the stopper 41 as shown in FIG. The sliding range of the stopper 41 is not limited. For this reason, the center phase can be changed by the phase changing mechanism 20 over the entire range from the most retarded phase P1 to the most advanced angle phase P2.

  As described above, according to the present embodiment, a simple structure using the arm 42 and the stopper 41 that are mechanically operated (rotated or slid) in accordance with changes in the operating angle and the center phase, By restricting the movement range to each other, a large operating angle state in which the operating angle is larger than the predetermined value Q3 and an advanced state in which the center phase is advanced from the predetermined phase P3 appear simultaneously, that is, in FIG. The situation of shifting to the area indicated by the oblique line α can be mechanically prohibited. Therefore, even during a control failure, the possibility of interference between the intake valve 1 and the piston can be completely eliminated.

DESCRIPTION OF SYMBOLS 1 ... Intake valve 10 ... Operating angle change mechanism 12 ... Operating angle control shaft 20 ... Phase change mechanism 21 ... Helical gear 41 ... Stopper (operating angle regulating body)
42 ... arm (phase regulator)
43 ... Phase control slider

Claims (2)

In a variable valve operating apparatus for an internal combustion engine, comprising: an operating angle changing mechanism that changes an operating angle of an intake valve; and a phase changing mechanism that changes a center phase of the operating angle of the intake valve.
An arm that operates mechanically in response to the change in the operating angle;
An operating angle restricting body that mechanically interlocks with the operation of the phase changing mechanism and restricts the expansion of the operating angle by restricting the movement range of the arm when the advance angle of the center phase is large;
A variable valve operating apparatus for an internal combustion engine, comprising: In a variable valve operating apparatus for an internal combustion engine, comprising: an operating angle changing mechanism that changes an operating angle of an intake valve; and a phase changing mechanism that changes a center phase of the operating angle of the intake valve.
A stopper that operates mechanically in response to the change in the center phase;
Mechanically interlocking with the operation of the operating angle changing mechanism, and when the operating angle is large, a phase restricting body that restricts the advance angle of the center phase by limiting the movement range of the stopper; and
A variable valve operating apparatus for an internal combustion engine, comprising:

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