JP2005076607A - Valve operation system for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the loss of power, and to improve durability in a structure for controlling valve lift quantity when opening an intake valve 3 or an exhaust valve of an internal combustion engine during operation of the internal combustion engine. <P>SOLUTION: The valve operation system is formed of a cam 5 to be rotated with a crank shaft and a swing member 9. A fulcrum member 13 is made to abut on a part of the swing member between one end and the other end thereof so that the swing member swings around the fulcrum member as the center of rotation. The swing member is structured to swing around the fulcrum member with rotation of the cam. The other end of the swing member is provided with a cam surface 18 for opening the intake valve 3 or the exhaust valve with swing of the the swing member, resisting a spring. Furthermore, the fulcrum member is moved toward one end side or the other end side in response to operating condition of the internal combustion engine. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a valve mechanism for opening at least one of the intake valve and the exhaust valve in a valve mechanism that opens and closes at least one of an intake valve and an exhaust valve in an internal combustion engine in conjunction with rotation of a crankshaft. The present invention relates to a valve mechanism that controls a lift amount and a working angle in accordance with the operating state of an internal combustion engine.

  In recent internal combustion engines, in order to improve fuel consumption and output, etc., the valve lift amount when opening the intake valve is small in the low load region of the internal combustion engine according to the operating state of the internal combustion engine. Control is performed so as to increase in a high load range.

With regard to this type of valve lift variable valve mechanism, Patent Document 1 as a prior art includes a valve cam that rotates in conjunction with a crankshaft in FIGS. The swinging member is brought into contact with the substantially intermediate portion between the one end and the other end so that the swinging member swings with the one end as a fulcrum of the rotation center by rotation of the cam. The cam surface formed on the upper part of the intake valve is brought into contact with the rocker arm with respect to the upper end of the intake valve so that the intake valve is opened against the spring by the swing of the swing member. According to the operating state of the internal combustion engine, the swinging angle by the cam of the swinging member is decreased in a low load range or a low rotation range, and is increased so as to increase in a high load range or a high rotation range. The amount of valve lift in the intake valve Small load region, it is proposed to control so as to increase in the high load region.
JP-A-7-63023

  However, the valve mechanism in this prior art uses the cam surface of the other end portion of the swing member as an operating point for the intake valve, while the swing member has a substantially intermediate portion between the one end portion and the other end portion. Is used as a force point for contact with the cam, and the swinging member is swung by rotation of the cam with one end portion being a fulcrum of the rotation center to open the intake valve against the spring. Therefore, in the swing member, the action length from the fulcrum at one end to the action point on the intake valve is much larger than the force point from the fulcrum at one end to the force point where the cam contacts. It is structured to be very long.

  In other words, the operation length from the fulcrum to the action point is significantly longer than the force point length from the fulcrum to the force point. It is necessary to apply a much larger operating force at the cam according to the ratio of the force point length to the action length than the spring force that keeps the intake valve closed with respect to the force point, Since a large amount of power is required to rotate the cam, there is a problem that not only the power loss is quite large but also the durability is very low.

  This invention makes it a technical subject to eliminate these problems.

In order to achieve this technical problem, claim 1 of the present invention provides:
“It is composed of a cam that rotates in conjunction with a crankshaft and a swinging member, and a fulcrum member is brought into contact with a portion between one end and the other end of the swinging member, and the swinging member The fulcrum member contact portion is configured to oscillate as a fulcrum of rotation center, and one end portion of the oscillating member is related to the cam so that the oscillating member is oscillated by rotation of the cam, The other end portion of the swing member is provided with a cam surface that opens and operates at least one of the intake valve and the exhaust valve against the spring by swinging the swing member. The contact portion of the member with respect to the swing member is configured to move to the one end side or the other end side in accordance with the operating state of the internal combustion engine.
It is characterized by that.

Further, according to claim 2 of the present invention, “in the cam surface of the swing member according to claim 1, the swing start portion of the swing member is not affected by the swing of the swing member. A non-moving section in which at least one of the intake valve and the exhaust valve is not opened or hardly opened is partially provided.
It is characterized by that.

  In the configuration described in claim 1, the swing member swings with the contact portion of the fulcrum member as the fulcrum of the rotation center by the rotation of the cam associated with the one end thereof. At the cam surface at the end, the intake valve or the exhaust valve opens and operates against the spring.

  Since the abutting portion of the fulcrum member, which is the fulcrum of the center of rotation of the oscillating member, is moved toward one end of the oscillating member, the oscillating angle of the oscillating member is increased. The valve lift amount when the valve or the exhaust valve opens increases.

  Further, by moving the contact portion of the fulcrum member with respect to the swing member toward the other end portion of the swing member, the swing angle of the swing member becomes small. The valve lift amount can be controlled during the operation of the internal combustion engine by the movement of the fulcrum member so that the valve lift amount when opening is small.

  The swinging member is a force point with which the cam at one end abuts, and the other end is an action point for the intake valve or the exhaust valve, and the fulcrum member abuts between these force points. The portion is a fulcrum of the center of rotation in the swinging member, and the force point length from the force point to the fulcrum can be brought close to the action length from the action point to the fulcrum, so that the force point length is the same as in the prior art. Can be prevented from being significantly longer than the working length.

  As a result, the operating force by the cam, and hence the power required to rotate the cam, can be reliably reduced, so that power loss can be reduced and durability can be greatly improved.

  Further, according to the configuration described in claim 2, as will be described in detail in the following embodiment, under a state where the maximum opening timing of the intake valve or the exhaust valve can be aligned with a substantially constant crank angle, Both the lift amount of the intake valve or the exhaust valve and the crank angle at which the intake valve or the exhaust valve is open, that is, the operating angle, can be controlled during operation of the internal combustion engine.

  In particular, in the case of claim 2, the fulcrum member is applied only to the intake valve, and the fulcrum member is arranged at one end side of the swing member in a high load or high rotation range according to the operation state in the internal combustion engine. By adopting a configuration that automatically moves to the other end side of the oscillating member in the low load or low rotation range, in addition to increasing the valve lift amount in the high load or high rotation range, the intake air Since the opening timing of the valve is early and the closing timing is delayed, the charging efficiency of intake air is improved and sufficient output can be ensured. On the other hand, in the low load or low rotation range, the valve lift amount becomes small. Since the opening timing of the intake valve is delayed and the overlap with the exhaust valve is reduced, fuel consumption is improved and stable rotation of the internal combustion engine is obtained. You can either also possible to control the intake air amount without intake throttle valve, it is also possible to improve fuel economy by reducing the pumping loss in Teiben lift range.

  Further, in the case of claim 2, it is applied only to the exhaust valve, and the fulcrum member is arranged on one end side of the swing member in a high load or high rotation range according to the operation state in the internal combustion engine. By adopting a configuration that automatically moves to the other end side of the swing member in the low load or low rotation range, the ratio of exhaust gas remaining in the cylinder and the internal EGR in the low load or low rotation range are set. In addition, since it is small in the high load or high rotation range and can be increased in the other operation range, the exhaust gas can be cleaned in the operation range other than the high load or high rotation range.

  1 to 4 showing the case where the embodiment of the present invention is applied to an intake valve will be described below.

  In this figure, reference numeral 1 denotes a cylinder head in an internal combustion engine. The cylinder head 1 is provided with an intake port 2 into a cylinder (not shown), and an opening of the intake port 2 into the cylinder includes An intake valve 3 that is normally closed by a spring 4 is provided.

  A cam shaft 6 having a cam 5 that opens and closes the intake valve 3 is pivotally supported on the cylinder head 1 so as to rotate in conjunction with a crankshaft in the internal combustion engine.

  The upper end of the intake valve 3 is in contact with the distal end of a rocker arm 8 whose base end is pivotally attached to a bolt 7 screwed to the cylinder head 1 side.

  Reference numeral 9 denotes a swing member. The swing member 9 is disposed between the cam 5 and the rocker arm 8, and an upper end portion of the swing member 9 contacts the cam 5. A roller 10 is rotatably provided by a pin shaft 11, and the upper end of the roller 10 is slidable in a guide groove 12 a in a pair of bracket bodies 12 in which the pin shaft 11 is provided integrally with the cylinder head 1. By being fitted, the cam 5 is supported so as to reciprocate in the radial direction.

  The upper end portion of the swing member 9 is positioned between the pair of bracket bodies 12 as shown in FIG. 2, and is configured to prevent movement in a direction perpendicular to the paper surface in FIG. doing.

  On the other hand, on the cylinder head 1 side, a base end of a fulcrum member 13 is rotatably supported by a pin shaft 14, and a roller 15 provided rotatably at the distal end of the fulcrum member 13 is attached to the swing member. 9 is in contact with the side surface of the portion between the upper end portion and the lower end portion thereof so as to be movable in the longitudinal direction of the swing member 9, while the roller 10 at the upper end portion of the swing member 9 is By pressing and urging the cam 5 with a return spring 16 provided between the lower end portion of the member 9 and the cylinder head 1, the swing member 9 is moved to the fulcrum by the rotation of the cam 5. The member 13 is configured to swing around a point where the roller 15 contacts the tip of the member 13 as a fulcrum of the rotation center.

  By providing a cam surface 18 in contact with a roller 17 rotatably provided on the rocker arm 8 at the lower end portion of the rocking member 9, the rocking member 9 can be swung through the rocker arm 8 by rocking. The intake valve 3 is configured to open and act against the spring 4.

  In addition to the above-described configuration, the fulcrum member 13 is moved by the actuator 19 that operates in accordance with the load in the internal combustion engine. The roller 15 at the tip is moved from the middle load region indicated by the solid line to the upper end side of the swinging member 9 when the load is high.

  In this case, the portion of the side surface of the swing member 9 that the roller 15 of the fulcrum member 14 contacts is formed on an arcuate surface 9a having a radius R centered on the rotation center of the fulcrum member 13, and The radius R in the circular arc surface 9a is made equal to the distance from the straight line 9b connecting the center of the pin shaft 11 at the upper end of the swing member 9 and the center of the roller 17 in the rocker arm 8 to the rotation center of the fulcrum member 13. Thus, the oscillating member 9 is moved in the lateral direction between the state where the fulcrum member 13 is moved to the upper end side of the oscillating member 9 and the state where the fulcrum member 13 is moved to the lower end side of the oscillating member 9. It is configured so that there is little displacement.

  The portion of the side surface of the rocking member 9 where the roller 15 of the fulcrum member 14 abuts is a parallel plane of the straight line 9b instead of the circular arc surface 9a as described above. By configuring the fulcrum member 13 to move in a direction parallel to the straight line 9b, the oscillating member 9 may be less displaced and displaced in the lateral direction.

  Further, the guide groove 12 with respect to the upper end of the swing member 9 extends in a direction perpendicular to the straight line 9 b of the swing member 9.

  In this configuration, the swinging member 9 swings with the rotation of the cam 5 with which the roller 10 abuts at the upper end of the swinging member 9 as the fulcrum of the rotation center at the location where the roller 15 abuts at the tip of the fulcrum member 13 At the cam surface 18 at the lower end of the swing member 9, the intake valve 3 is pushed downward against the spring via the rocker arm 8 to open.

  When the load in the internal combustion engine increases to a high load region, the roller 15 at the tip of the fulcrum member 13 moves to the upper end side of the swing member 9 rather than in the middle load region indicated by the solid line, thereby swinging. The force point length from the force point F at which the roller 10 at the upper end of the member 9 contacts the cam 5 to the fulcrum S at which the roller 15 at the tip of the fulcrum member 13 contacts the swing member 9 is in the middle load range. While the force point length is reduced from X0 to X1, the action point length from the action point W where the cam surface 18 at the lower end of the rocking member 9 contacts the roller 17 in the rocker arm 8 to the fulcrum S is the medium load. Since the operating point length Y0 in the region increases from Y1 to Y1, the swinging angle of the swinging member 9 with respect to the crank angle θ of the intake valve opening set in the cam 6 increases, and as shown in FIG. The relative movement distance is long in the L1 against roller 17 of the rocker arm 8 in the cam surface 18 of its lower end, performing the opening operation of the intake valves 3 during this long movement distance L1.

  When the load in the internal combustion engine falls to a low load range, the roller 15 at the tip of the fulcrum member 13 moves to the lower end side of the swinging member 9 from the middle load range shown by the solid line, so that the power point length is increased. Is longer from the power point length X0 to X2 in the middle load region, while the action point length is shorter from the action point length Y0 to Y2 in the middle load region. The swinging angle of the swinging member 9 with respect to the crank angle θ is reduced. As a result, as shown in FIG. 3, the relative movement distance of the rocker arm 8 with respect to the roller 17 on the cam surface 18 at its lower end is shortened to L2. Thus, the opening operation of the intake valve 3 is performed during this short movement distance L2.

  That is, in the high load range, the swing angle of the swing member 9 and, consequently, the moving distance L1 on the cam surface 18 become large, so that the intake valve 3 has a profile as shown by a solid line A1 in FIG. Therefore, the maximum valve lift amount H1 is higher than the maximum valve lift amount H0 in the middle load range.

  On the other hand, in the low load range, the swinging angle of the swinging member 9 and, consequently, the moving distance L2 on the cam surface 18 are reduced, so that the intake valve 3 is shown by a two-dot chain line A2 in FIG. Therefore, the maximum valve lift amount H2 is lower than the maximum valve lift amount H0 in the middle load region.

  Thereby, the valve lift amount when the intake valve 3 is opened and operated can be automatically controlled to be large at high load and small at low load according to the load of the internal combustion engine.

  Next, FIGS. 5 and 6 show a second embodiment.

  In the second embodiment, even if the swing member 9 swings on the swing start portion of the swing member 9 in the cam surface 18 at the lower end of the swing member 9, the intake valve 3 is provided with a non-moving section L0 in which the opening operation is not performed or the opening operation is hardly performed.

  As a result, the opening operation of the intake valve 3 is performed in the section of L1-L0 = L1 ′ obtained by subtracting the non-moving section L0 from the moving distance L1 in the high load area, and in the low load area. This is performed in a section of L2−L0 = L2 ′ obtained by subtracting the non-moving section L0.

  That is, in the high load region, the swinging angle of the swinging member 9 and the movement distance on the cam surface 18 are as large as L1−L0 = L1 ′, so that the intake valve 3 is shown by a solid line A1 ′ in FIG. Therefore, the maximum valve lift amount H1 ′ is higher than the maximum valve lift amount H0 ′ in the middle load region, and the crank angle when the intake valve 3 is open is shown in FIG. That is, the operating angle θ1 for opening the intake valve 3 is also larger than the operating angle θ0 in the middle load range.

  On the other hand, in the low load region, the swinging angle of the swinging member 9, and hence the moving distance on the cam surface 18, is reduced to L2−L0 = L2 ′. Since the opening operation is performed with a profile as indicated by a chain line A2 ′, the maximum valve lift amount H2 ′ is lower than the maximum valve lift amount H0 ′ in the middle load region, and the intake valve 3 is open. The crank angle, that is, the operating angle θ2 for opening the intake valve 3 is also smaller than the operating angle θ0 in the middle load region.

  Thereby, the valve lift amount and the operating angle when the intake valve 3 is opened and operated can be controlled to be large at high load and small at low load according to the load of the internal combustion engine.

  In addition, a non-moving section L0 in which the intake valve 3 is not opened and operated even when the swinging member 9 swings is provided in the swing start portion of the swinging member 9 in the cam surface 18. Accordingly, the opening operation of the intake valve 3 starts after the non-moving section L0 from the start of swinging of the swinging member 9.

  In this case, since the non-moving section L0 is always constant in the high load region and the low load region, the non-moving section L0 corresponds to the movement distances L1 and L2, and consequently the swing angle of the swing member 9. The ratio is small in the high load region and large in the low load region.

  Thereby, in the low load range, the timing D2 at which the intake valve 3 starts to open in synchronization with the rotation of the crankshaft is delayed by Δθ1 in the crank angle from the timing D1 at which the intake valve 3 starts to open in the high load range. The timing E2 when the intake valve 3 is closed is earlier by Δθ2 in crank angle than the timing E1 when the intake valve 3 is in a high load range. As a result, the time when the intake valve 3 is opened to the maximum in the low load region, that is, the time when the intake valve 3 is opened to the maximum can be substantially aligned with the time when the intake valve 3 is opened in the high load region.

  In the above embodiment, the control is performed according to the load. However, the present invention is not limited to this, and the control is performed according to the rotational speed, or the control is performed according to the load and the rotational speed. Needless to say, it's okay.

It is a figure which shows 1st Embodiment in this invention. FIG. 2 is a sectional view taken along line II-II in FIG. 1. It is an enlarged view which shows the principal part of FIG. It is a figure which shows the profile of the intake valve in the said 1st Embodiment. It is an enlarged view which shows the principal part in 2nd Embodiment. It is a figure which shows the profile of the intake valve in the said 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cylinder head 2 Intake port 3 Intake valve 4 Intake valve spring 5 Cam 6 Cam shaft 8 Rocker arm 9 Oscillating member 10 Roller 11 Pin shaft 12 Guide groove 13 Supporting member 14 Pin shaft of supporting member 15 Roller 16 Returning spring 17 Roller 18 Cam surface

Claims (2)

  The oscillating member comprises a cam that rotates in conjunction with a crankshaft and a oscillating member. A fulcrum member is contacted to a portion between one end and the other end of the oscillating member, and the oscillating member is supported by the fulcrum. The contact portion of the member is configured to swing as a fulcrum of rotation center, and one end of the swing member is related to the cam, and the swing member is swung by rotation of the cam, A cam surface is provided at the other end of the swing member so that at least one of the intake valve and the exhaust valve is opened against the spring by swinging the swing member, and the fulcrum member is further provided. A valve operating mechanism in an internal combustion engine, wherein a contact portion with respect to the rocking member is moved to the one end side or the other end side in accordance with an operating state of the internal combustion engine.   In the first aspect of the present invention, at least one of the intake valve and the exhaust valve is opened at a swing start portion of the swing member on the cam surface of the swing member regardless of the swing of the swing member. A valve operating mechanism in an internal combustion engine, characterized in that a non-moving section that does not operate or hardly opens is partially provided.

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