JP5212166B2 - Variable valve operating device for internal combustion engine - Google Patents

Description

  The present invention relates to a variable valve operating apparatus for an internal combustion engine.

  For example, Patent Document 1 discloses a variable valve gear that can control two engine valves provided per cylinder to different lift amounts.

  In Patent Document 1, it is possible to variably control one engine valve after a pair of engine valves of the same cylinder from a valve stop state to a maximum lift substantially equal to the other engine valve.

JP 2000-38910 A

  However, in Patent Document 1, although a pair of engine valves of the same cylinder can be set to substantially the same maximum lift amount, a pair of engine valves of the same cylinder can be set to a maximum lift amount together with a pair of engine valves of the same cylinder. There is a problem that the valve opening characteristics from the opening timing of the engine valve to the maximum lift, that is, the opening characteristics of the pair of engine valves cannot be made close to the crank angle.

  That is, when there is an operating condition in which a pair of engine valves of the same cylinder have different lift amounts during partial load, and an operating condition in which a pair of engine valves of the same cylinder have the same lift amount at high loads, However, when the pair of engine valves is set to the maximum lift amount, there is a problem that the opening characteristics of the pair of engine valves cannot be made close to the crank angle.

  Therefore, a variable valve operating apparatus for an internal combustion engine according to the present invention includes a drive shaft, a crank-shaped control shaft having a main shaft portion and an eccentric cam portion eccentric to the main shaft portion, and a pair of cylinders provided in the same cylinder. A first swing cam that opens and closes one of the intake valves, a second swing cam that opens and closes the other of a pair of intake valves provided in the same cylinder, and the first swing cam as the drive shaft rotates. A first drive force transmission mechanism that swings one swing cam; and a second drive force transmission mechanism that swings the second swing cam as the drive shaft rotates, and the eccentric cam portion Is composed of a first eccentric cam portion and a second eccentric cam portion having a larger amount of eccentricity with respect to the main shaft portion than the first eccentric cam portion, and the first eccentric cam portion is moved along with the rotation of the main shaft portion. And changing the attitude of the first driving force transmission mechanism through the opening / closing period and lift amount of the one intake valve Continuously variable, and with the rotation of the main shaft portion, the posture of the second driving force transmission mechanism is changed via the second eccentric cam portion, and the open / close period of the other intake valve is changed. In a region where the lift amount can be continuously varied and the valve lift characteristic of the intake valve is set to a small lift and small operating angle, the rotation of the main shaft portion of the control shaft is the first power transmission mechanism and the second power transmission. In the region where the transmission is transmitted to both mechanisms and the valve lift characteristic of the intake valve is set to a large lift and large operating angle, the rotation of the main shaft portion of the control shaft is transmitted only to the first power transmission mechanism. Since the first eccentric cam portion has a smaller amount of eccentricity with respect to the main shaft portion than the second eccentric cam portion, the rotation angle around the main shaft portion of the first eccentric cam portion accompanying the rotation of the main shaft portion, and the main shaft When the rotation angle around the main shaft portion of the second eccentric cam portion accompanying the rotation of the portion is equal, the lift amount of the intake valve opened and closed by the first driving force transmission mechanism is the second driving force transmission mechanism It becomes smaller than the lift amount of the intake valve that is opened and closed by.

  According to the present invention, in the partial load region where the valve lift characteristic of the intake valve is a small lift and small operating angle, the lift amount of one intake valve that is opened and closed by the first swing cam and the second swing cam that opens and closes Thus, the lift amount of the other intake valve can be made different from each other, and the gas flow in the cylinder can be strengthened.

  Further, in a high load range where the valve lift characteristic of the intake valve is a large lift and a large operating angle, the rotation angle around the main shaft portion of the first eccentric cam portion is larger than the rotation angle around the main shaft portion of the second eccentric cam portion. Therefore, it is possible to change only the valve lift characteristic of one intake valve opened and closed by the first swing cam with respect to the other intake valve opened and closed by the second swing cam. The valve lift characteristics of the two intake valves can be brought close to each other, and the output characteristics can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS Explanatory drawing which showed typically the variable valve apparatus of the internal combustion engine which concerns on this invention. BRIEF DESCRIPTION OF THE DRAWINGS Explanatory drawing which showed typically the principal part of the variable valve operating apparatus of the internal combustion engine which concerns on this invention. Explanatory drawing which showed the connection mechanism typically. Explanatory drawing which showed the connection mechanism typically. The variable valve operating apparatus of the internal combustion engine which concerns on this invention WHEREIN: Explanatory drawing which shows the valve lift characteristic when an intake valve is a small lift small operating angle. In the variable valve operating apparatus of the internal combustion engine which concerns on this invention, explanatory drawing which shows the valve lift characteristic when an intake valve is a large lift large operating angle. Explanatory drawing which shows the valve lift characteristic when an intake valve is a large lift large operating angle in a comparative example.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is an explanatory view schematically showing a variable valve operating apparatus 10 for an internal combustion engine according to the present invention.

  The variable valve operating apparatus 10 of this embodiment includes two intake valves (not shown) per cylinder, and can change the lift amount of a pair of intake valves of the same cylinder according to the operating state of the internal combustion engine. It is.

  More specifically, the variable valve apparatus 10 of the present embodiment has a lower lift amount and a lift operating angle of the intake valve, that is, an intake air, in the low speed and low load range, which is a partial load range, compared to the high speed and high load range. The valve opening period can be changed so that the lift amount becomes larger in the high speed and high load range than in the low speed and low load range, and the lift operating angle of the intake valve, that is, the intake valve open period It can be changed to be larger. That is, in the variable valve operating apparatus 10, when the lift amount of the intake valve increases, the lift operation angle of the intake valve also increases, and when the lift amount of the intake valve decreases, the lift operation angle of the intake valve also decreases.

  The variable valve gear 10 is rotatably supported on the cylinder head along the longitudinal direction of the engine (cylinder row direction), and is provided on the outer periphery of the drive shaft 11. The drive shaft 11 rotates in synchronization with the rotation of the internal combustion engine. A crank-shaped control shaft having two drive cams 112a and 112b per cylinder and a main shaft portion 131 and an eccentric cam portion 132 that is eccentric with respect to the main shaft portion 131. 13, a first swing cam 16a that opens and closes one of a pair of intake valves provided in the same cylinder, and a second swing cam that opens and closes the other of the pair of intake valves provided in the same cylinder 16b, a first drive force transmission mechanism 18a interposed between the first drive cam 112a and the first swing cam 16a and swinging the first swing cam 16a as the drive shaft 11 rotates, Second drive cam 112b and second It is interposed between the movement cam 16b, and is largely constituted by a second driving force transmission mechanism 18b for swinging the second swing cam 16b with the rotation of the drive shaft 11. The drive shaft 11 and the control shaft 13 are rotatably supported by a bearing (not shown). Although FIG. 1 shows only one cylinder, the drive shaft 11 and the control shaft 13 are actually common to a plurality of cylinders and extend along the longitudinal direction of the engine.

  The drive shaft 11 is rotated by torque transmitted from a crankshaft (not shown) of the internal combustion engine, and includes a cylindrical drive shaft main body 111 and drive cams 112a and 112b. The drive cams 112 a and 112 b are eccentric rotating cams that are offset from the axis of the drive shaft main body 111, and are fixed to the drive shaft main body 111 by connecting pins (not shown), respectively. Rotate. The shaft centers of the drive cams 112a and 112b are set to be offset from the shaft center of the drive shaft main body 111 by a predetermined amount in the radial direction.

  The first driving force transmission mechanism 18a is provided in a first eccentric cam portion 132a (described later) of the control shaft 13, and when the control shaft 13 rotates, its posture is changed via the first eccentric cam portion 132a, The opening / closing period and the lift amount of one of the pair of intake valves of the same cylinder are continuously varied.

  The second driving force transmission mechanism 18b is provided in a second eccentric cam portion 132b (described later) of the control shaft 13, and when the control shaft 13 rotates, its posture is changed via the second eccentric cam portion 132b. The open / close period and lift amount of the other intake valve of the pair of intake valves of the same cylinder are continuously varied.

  The first driving force transmission mechanism 18a is rotatably attached to the first link arm 12a fitted to the outer periphery of the driving cam 112a so as to be relatively rotatable, and the first eccentric cam portion 132a of the control shaft 13, and is connected to the first link. The first swing arm 14a is swung by the arm 12a, and the first link rod 15a is connected to the first swing arm 14a and the first swing cam 16a.

  The second driving force transmission mechanism 18b is rotatably attached to the second link arm 12b fitted to the outer periphery of the driving cam 112b so as to be relatively rotatable, and the second eccentric cam portion 132b of the control shaft 13, and the second link. It is generally composed of a second swing arm 14b that is swung by the arm 12b, and a second link rod 15b that connects the second swing arm 14b and the second swing cam 16b.

  The first swing arm 14a is roughly configured by a cap 141a and an arm body 142a having a cylindrical pin portion 21a linked to the first link arm 12a, and is closer to the drive shaft 11 than the cap 141a and the cap 141a. The first eccentric cam portion 132a is sandwiched between the arm body 142a positioned at the position and is rotatably supported. The cap 141a and the arm body 142a are coupled by a bolt 38a.

  One end of the first link rod 15a is connected to the arm body 142a of the first swing arm 14a via a pin 22a, and the other end is connected to the first swing cam 16a via a pin 23a as a rotation fulcrum. Yes. Here, the pin 22a is further away from the axis of the first eccentric cam portion 132a than the pin portion 21a.

  The first swing cam 16a is swingably supported by the drive shaft 11, and is not included in a pair of intake valves of the same cylinder by a valve rocker arm (not shown) pressed by the swing of the first swing cam 16a. One intake valve opens and closes.

  The second swing arm 14b is generally configured by a cap 141b and an arm body 142b having a columnar pin portion 21b linked to the second link arm 12b, and is closer to the drive shaft 11 than the cap 141b and the cap 141b. The second eccentric cam portion 132b is sandwiched between the arm body 142b positioned at the position and is rotatably supported. The cap 141b and the arm body 142b are coupled by a bolt 38b.

  One end of the second link rod 15b is connected to the arm body 142b of the second swing arm 14b via a pin 22b, and the other end is connected to the second swing cam 16b via a pin 23b as a rotation fulcrum. Yes. Here, the pin 22b is farther from the axis of the second eccentric cam portion 132b than the pin portion 21b.

  The second rocking cam 16b is supported by the drive shaft 11 so as to be rockable, and the valve rocker arm (not shown) pressed by the rocking of the second rocking cam 16b is used as a pair of intake valves of the same cylinder. The other intake valve opens and closes.

  The control shaft 13 has a crank shape in which the shaft center of the eccentric cam portion 132 is offset with respect to the shaft center of the main shaft portion 131, and both ends of the eccentric cam portion 132 are connected to the web plate 133. The eccentric cam portion 132 includes a first eccentric cam portion 132a and a second eccentric cam portion 132b having a larger amount of eccentricity with respect to the main shaft portion 131 than the first eccentric cam portion 132a.

  2 to 4, the first eccentric cam portion 132a is connected and fixed to the main shaft portion 131 via the web plate 133a. More specifically, the first eccentric cam portion 132 a is fixed to the main shaft portion 131 and is configured to always swing as the main shaft portion 131 rotates. On the other hand, the second eccentric cam portion 132b is supported so as to be swingable with respect to the main shaft portion 131 via the web plate 133b. That is, the second eccentric cam portion 132b and the web plate 133b are not fixed to the main shaft portion 131, and the second eccentric cam portion 132b is connected and fixed to the first eccentric cam portion 132a via the connection mechanism 31. It has a possible configuration. More specifically, the second eccentric cam portion 132b and the web plate 133b do not necessarily oscillate as the main shaft portion 131 rotates, and the second eccentric cam portion 132b is connected to the first eccentric cam portion 132a by the connecting mechanism 31. In this state, the rotation of the main shaft portion 131 is transmitted to the second eccentric cam portion 132b and the web plate 133b.

  As shown in FIGS. 3 and 4, the coupling mechanism 31 can connect and release the first eccentric cam portion 132 a and the second eccentric cam portion 132 b with a pin member 32, and has a step. A cylindrical pin member 32, a spring member 33 that constantly urges the pin member 32 toward the second eccentric cam portion 132b, and a second eccentric cam portion 132b that contacts the one end surface 34 of the first eccentric cam portion 132a. An arc-shaped groove portion 36 formed in the end face 35 and an engagement hole portion 37 formed on one end side of the groove portion 36 are provided.

  The engagement hole portion 37 is formed in a size that can accommodate the tip of the pin member 32 and can supply hydraulic oil. In a state where the tip of the pin member 32 is accommodated in the engagement hole 37 and the second eccentric cam portion 132b is connected to the first eccentric cam portion 132a, hydraulic oil is supplied to the engagement hole 37 from the oil passage 38. Then, the pin member 32 is retracted against the urging force of the spring member 33 due to the hydraulic pressure, and the pin member 32 comes out of the engagement hole portion 37, so that the first eccentric cam portion 132a and the second eccentric cam portion 132b The connection is released. At this time, when the control shaft 13 rotates in the direction of increasing the lift amount and lift operating angle of the intake valve, the rotation of the main shaft portion 131 is transmitted to the first eccentric cam portion 132a, and the main shaft portion is transmitted to the second eccentric cam. The rotation of 131 is not transmitted. More specifically, when the connection between the first eccentric cam portion 132a and the second eccentric cam portion 132b is released, the main shaft portion 131 of the control shaft 13 makes the valve lift characteristic of the intake valve a large lift large operating angle. 4, only the first eccentric cam portion 132 a rotates around the main shaft portion 131 in the counterclockwise direction in FIG. 4 as the main shaft portion 131 of the control shaft 13 rotates. At this time, the tip of the pin member 32 moves in the groove 36 in the direction indicated by the arrow A in FIG. In the present embodiment, the first eccentric cam portion 132a and the second eccentric cam portion 132b are set to be disconnected during a high load operation.

  Here, the control shaft 13 is controlled by the actuator 39 so as to rotate within a predetermined rotation angle range. The actuator 39 controls the rotation of the control shaft 13 based on the current operating state of the internal combustion engine detected from detection signals from various sensors such as a crank angle sensor, an air flow meter, and a water temperature sensor.

  As described above, in the present embodiment, since the first eccentric cam portion 132a has a smaller amount of eccentricity with respect to the main shaft portion 131 than the second eccentric cam portion 132b, the first eccentric cam portion 132a has the second eccentric cam portion. In the low load region where 132b is connected, both the first eccentric cam portion 132a and the second eccentric cam portion 132b swing as the main shaft portion 131 of the control shaft 13 rotates, as shown in FIG. The lift amount of one intake valve of the pair of intake valves opened and closed by the first swing cam 16a is larger than the lift amount of the other intake valve of the pair of intake valves opened and closed by the second swing cam 16b. It is getting smaller. In other words, since the first eccentric cam portion 132a has a smaller amount of eccentricity with respect to the main shaft portion 131 than the second eccentric cam portion 132b, the first eccentric cam portion 132a is rotated around the main shaft portion of the first eccentric cam portion 132a as the main shaft portion 131 rotates. And the rotation angle around the main shaft portion of the second eccentric cam portion 132b associated with the rotation of the main shaft portion 131 of the control shaft 13 are equal to each other through the first eccentric cam portion 132a. The lift amount of one intake valve that is opened and closed by the driving force transmission mechanism 18a is larger than the lift amount of the other intake valve that is opened and closed by the second driving force transmission mechanism 18b that changes its posture via the second eccentric cam portion 132b. Get smaller.

  Therefore, in a low load range where the valve lift characteristic of the intake valve is a small lift and a small operating angle, the second swing cam portion 132b is connected to the first swing cam portion 132a. The lift amount of one intake valve that is opened and the lift amount of the other intake valve that is opened and closed by the second swing cam 16b can be made different from each other, and the gas flow in the cylinder is strengthened. Can do.

  On the other hand, in the high load region in which the connection between the first eccentric cam portion 132a and the second eccentric cam portion 132b is released, only the first eccentric cam portion 132a swings as the main shaft portion 131 of the control shaft 13 rotates. Therefore, only the valve lift characteristic of one of the pair of intake valves can be changed, and the valve lift characteristics of the pair of intake valves of the same cylinder can be matched as shown in FIG.

  In other words, in a high load range where the valve lift characteristic of the intake valve is a large lift and large operating angle, the rotation angle around the main shaft portion of the first eccentric cam portion 132a is the rotation angle around the main shaft portion of the second eccentric cam portion 132b. It is possible to change only the valve lift characteristic of one intake valve that is opened and closed by the first driving force transmission mechanism 18a with respect to the other intake valve that is opened and closed by the second driving force transmission mechanism 18b. Therefore, the valve lift characteristics of the two intake valves of the same cylinder can be matched, and the output characteristics can be improved.

  By changing the cam profiles of the first rocking cam 16a and the second rocking cam 16b, the lift amount of the pair of intake valves of the same cylinder is set to be different from each other in the low load range. When the lift amount of a pair of intake valves of the same cylinder is set to be the same in the high load region, as shown in FIG. 7, the valve of the intake valve S that has a relatively small lift in the low load region. The so-called skirt portion of the lift characteristic is thinner than the skirt portion of the valve lift characteristic of the intake valve L, which has a relatively large lift in the low load range, and accordingly, the output is reduced accordingly. .

  The technical ideas of the present invention that can be grasped from the above-described embodiments will be listed together with their effects.

  (1) A variable valve operating apparatus for an internal combustion engine is provided so as to be rotatable in parallel with the drive shaft, a drive cam provided on the outer periphery of the drive shaft, and a drive shaft that rotates in synchronization with the rotation of the internal combustion engine. A crank-shaped control shaft having a main shaft portion and an eccentric cam portion eccentric to the main shaft portion, and a first swing cam that opens and closes one of a pair of intake valves provided in the same cylinder A second rocking cam that opens and closes the other of the pair of intake valves provided in the cylinder, and is interposed between the drive cam and the first rocking cam, and with the rotation of the drive shaft, A first drive force transmission mechanism for swinging the first swing cam, and interposed between the drive cam and the second swing cam, and with the rotation of the drive shaft, A second driving force transmission mechanism that swings, wherein the eccentric cam portion includes a first eccentric cam portion and the first eccentric cam portion. A second eccentric cam portion having a larger amount of eccentricity with respect to the main shaft portion than the main portion, and the first driving force transmission mechanism via the first eccentric cam portion as the main shaft portion of the control shaft rotates. The opening / closing period and the lift amount of the one intake valve can be continuously changed, and the rotation of the main shaft portion of the control shaft can be changed via the second eccentric cam portion. In the region where the attitude of the second driving force transmission mechanism is changed, the open / close period of the other intake valve and the lift amount are continuously variable, and the valve lift characteristic of the intake valve is a small lift and small operating angle In the region where the rotation of the main shaft portion of the control shaft is transmitted to both the first power transmission mechanism and the second power transmission mechanism and the valve lift characteristic of the intake valve is a large lift large operating angle, the control shaft The rotation of the main shaft of the first power transmission mechanism Only communicate. Since the first eccentric cam portion has a smaller amount of eccentricity with respect to the main shaft portion than the second eccentric cam portion, the rotation angle around the main shaft portion of the first eccentric cam portion accompanying the rotation of the main shaft portion of the control shaft, and the main shaft of the control shaft When the rotation angle around the main shaft portion of the second eccentric cam portion associated with the rotation of the portion is equal, one intake valve that is opened and closed by the first driving force transmission mechanism that changes its posture via the first eccentric cam portion The lift amount is smaller than the lift amount of the other intake valve that is opened and closed by the second driving force transmission mechanism whose posture changes via the second eccentric cam portion.

  Thus, in the partial load region where the valve lift characteristic of the intake valve is a small lift and small operating angle, the lift amount of one intake valve opened and closed by the first swing cam and the other opened and closed by the second swing cam The lift amount of the intake valve can be different from each other, and the gas flow in the cylinder can be enhanced.

  Further, in a high load range where the valve lift characteristic of the intake valve is a large lift and a large operating angle, the rotation angle around the main shaft portion of the first eccentric cam portion is larger than the rotation angle around the main shaft portion of the second eccentric cam portion. Therefore, it is possible to change only the valve lift characteristic of one intake valve opened and closed by the first swing cam with respect to the other intake valve opened and closed by the second swing cam. The valve lift characteristics of the two intake valves can be brought close to each other, and the output characteristics can be improved.

  (2) In the valve operating apparatus for an internal combustion engine according to (1), the first eccentric cam portion is fixed to the main shaft portion, and always rotates with the rotation of the main shaft portion, and the second The eccentric cam portion is rotatably supported with respect to the main shaft portion and can be connected to the first eccentric cam portion via a connection mechanism, and the connection mechanism is configured to be a first eccentric cam in a low load region. And the second eccentric cam portion are connected, and in the high load region, the connection between the first eccentric cam portion and the second eccentric cam portion is released.

DESCRIPTION OF SYMBOLS 10 ... Variable valve apparatus 11 ... Drive shaft 13 ... Control shaft 131 ... Main shaft part 132a ... 1st eccentric cam part 132b ... 2nd eccentric cam part 16a ... 1st rocking cam 16b ... 2nd rocking cam 18a ... 1st Driving force transmission mechanism 18b ... second driving force transmission mechanism 31 ... connection mechanism 32 ... pin member 33 ... spring member 36 ... groove 37 ... engagement hole

Claims (2)

A drive shaft that rotates in synchronization with the rotation of the internal combustion engine;
A drive cam provided on the outer periphery of the drive shaft;
A crank-shaped control shaft provided rotatably in parallel with the drive shaft and having a main shaft portion and an eccentric cam portion eccentric with respect to the main shaft portion;
A first rocking cam that opens and closes one of a pair of intake valves provided in the same cylinder;
A second swing cam that opens and closes the other of the pair of intake valves provided in the same cylinder;
A first driving force transmission mechanism interposed between the drive cam and the first swing cam and swinging the first swing cam as the drive shaft rotates;
A second driving force transmission mechanism interposed between the drive cam and the second swing cam and swinging the second swing cam as the drive shaft rotates,
The eccentric cam portion includes a first eccentric cam portion and a second eccentric cam portion having a larger amount of eccentricity with respect to the main shaft portion than the first eccentric cam portion,
As the main shaft portion of the control shaft rotates, the posture of the first driving force transmission mechanism is changed via the first eccentric cam portion, and the open / close period and lift amount of the one intake valve are continuously changed. And the posture of the second driving force transmission mechanism is changed via the second eccentric cam portion with the rotation of the main shaft portion of the control shaft, and the opening and closing period of the other intake valve And the lift amount can be changed continuously,
In a region where the valve lift characteristic of the intake valve is a small lift and small operating angle, the rotation of the main shaft portion of the control shaft is transmitted to both the first power transmission mechanism and the second power transmission mechanism,
The variable valve operating apparatus for an internal combustion engine, wherein the rotation of the main shaft portion of the control shaft is transmitted only to the first power transmission mechanism in a region where the valve lift characteristic of the intake valve is a large lift and large operating angle. The first eccentric cam portion is fixed to the main shaft portion, and always rotates with the rotation of the main shaft portion,
The second eccentric cam portion is rotatably supported with respect to the main shaft portion, and can be connected to the first eccentric cam portion via a connection mechanism,
The connecting mechanism connects the first eccentric cam portion and the second eccentric cam portion in a low load region, and releases the connection between the first eccentric cam portion and the second eccentric cam portion in a high load region. The variable valve operating apparatus for an internal combustion engine according to claim 1.

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