JP4271152B2 - Engine vibration removal device - Google Patents

Description

The present invention changes the piston stroke characteristics according to the operating state of the engine to change the compression ratio of the engine between a high compression ratio state where the top dead center position of the piston is the highest and a low compression ratio state where the piston is at the lowest. a stroke characteristic variable mechanism for changing between relates to a vibration removal equipment of an engine and a secondary balancer apparatus for reducing secondary vibration of the engine caused by the reciprocating motion of the piston.

A lower link is pivotally supported on the crankpin of the crankshaft, and the lower link is connected to the piston via the upper link, and the lower link is connected to the control shaft supported by the engine block via the control link. Patent Documents 1 and 2 listed below disclose a multi-link engine that changes the compression ratio by changing the position of one end of a control link by rotating the shaft with an actuator.
JP 2002-188455 A JP 2002-174131 A

  By the way, in the multi-link type engine having links other than the connecting rod, since these links are arranged asymmetrically with respect to the cylinder axis, the direction of the secondary vibration generated by the reciprocation of the piston is the cylinder axis. It will be inclined with respect to the direction. Moreover, when the control shaft is rotated to change the compression ratio, the arrangement relationship of the plurality of links is shifted, and the vibration characteristics, particularly the direction of the secondary vibration, change.

  Therefore, even if a secondary balancer device is attached to such an engine to reduce the secondary vibration, the secondary vibration when the engine is in the high compression ratio state and the secondary vibration when the engine is in the low compression ratio state are reduced. There is a problem that it is difficult to reduce both.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to effectively remove vibrations of an engine capable of switching a plurality of operating states having different piston stroke characteristics.

In order to achieve the above object, according to the first aspect of the present invention, the piston stroke characteristic is changed according to the operating state of the engine to change the compression ratio of the engine, and the top dead center position of the piston is the highest. An engine having a variable stroke characteristic mechanism that changes between a high compression ratio state that becomes the lowest and a low compression ratio state that is the lowest, and a secondary balancer device that reduces secondary vibrations of the engine due to the reciprocation of the piston The crankshaft of the engine is arranged such that the axis of the engine is biased to one side with respect to the cylinder axis, and the variable stroke characteristic mechanism includes an upper link connected to a piston, the upper link and the Lower link connected to the crankshaft, one end connected to the lower link and the other end connected to the engine block via the control shaft Movably supported control link to click, and with which an actuator for driving the control shaft, and between the control shaft and the control link are disposed on the one side with respect to the cylinder axis, wherein The direction of the excitation force generated by the secondary balancer device is such that the downward excitation force is directed to the one side with respect to the cylinder axis, and the upward excitation force is directed to the other side with respect to the cylinder axis. and it is inclined with respect to the cylinder axis, and the direction of the exciting force the secondary balancer device occurs, the direction of vibration force said that give suppressing secondary vibration in the high compression ratio state, vibration removing device proposed of the engine, wherein the set in the middle direction between the direction of the secondary vibration that obtained by the suppression exciting force at a low compression ratio state That.

According to the invention described in claim 2, in addition to the first aspect, the direction of the exciting force the secondary balancer device generates the amplitude of the secondary vibration in a high compression ratio state , the vibration removing device of the engine, characterized in that the amplitude of the secondary vibration in the low compression ratio state is set to be substantially equal Ru been proposed.

According to the configuration of the first aspect, the piston stroke characteristic is changed in accordance with the operating state of the engine, so that the engine compression ratio becomes the lowest in the high compression ratio state where the top dead center position of the piston is the highest. In an engine vibration elimination apparatus comprising a stroke characteristic variable mechanism that changes between a low compression ratio state and a secondary balancer device that reduces secondary vibration of the engine due to reciprocation of a piston, the engine crankshaft is The stroke characteristic variable mechanism is arranged such that the shaft axis is biased to one side with respect to the cylinder axis. A controller with one end connected to the link and the other end movably supported on the engine block via the control shaft A vibration source generated by the secondary balancer device, having a link and an actuator for driving the control shaft, wherein the control shaft and the control link are disposed on the one side with respect to the cylinder axis. The direction of the force is inclined with respect to the cylinder axis so that the downward excitation force is directed to the one side with respect to the cylinder axis and the upward excitation force is directed to the other side with respect to the cylinder axis. And the direction of the exciting force generated by the secondary balancer device is the direction of the exciting force capable of suppressing the secondary vibration in the high compression ratio state and the secondary force in the low compression ratio state. because it is set in the middle direction between the direction of the excitation force capable of suppressing vibration, the direction of the secondary vibration generated with the reciprocating motion of the piston and a high compression ratio state and a low compression ratio state Be different, it is possible to effectively suppress both secondary vibration in a high compression ratio condition and a low compression ratio state.

According to the second aspect, the direction of the excitation force secondary balancer device generates, the amplitude of the secondary vibration in a high compression ratio condition and a low compression ratio state is set to be substantially equal, high Both secondary vibrations in the compression ratio state and the low compression ratio state can be more effectively suppressed.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on examples of the present invention shown in the accompanying drawings.

  1 to 8 show an embodiment of the present invention. FIG. 1 is a longitudinal sectional view of a variable compression ratio engine (high compression ratio state), and FIG. 2 is a view taken along the line 2-2 in FIG. 3 is a view taken along line 3-3 in FIG. 1, FIG. 4 is a view taken in the direction of arrow 4 in FIG. 1, FIG. 5 is a longitudinal sectional view of a variable compression ratio engine (low compression ratio state), and FIG. FIG. 7 is a graph showing the direction of the secondary vibration of the engine, and FIG. 8 is a graph showing the effect of the secondary balancer device.

  As shown in FIGS. 1 to 4, the variable compression ratio engine E, which is an example of a variable stroke characteristic engine that can change the position to the top dead center or the bottom dead center of the piston by providing a plurality of links, And an engine block 13 coupled to the crankcase 12. A cylinder head 14 and a head cover 15 are coupled to the upper part of the cylinder block 11, and an oil pan 16 is coupled to the lower part of the crankcase 12. A main journal 17a of the crankshaft 17 is rotatably supported on the split surfaces of the cylinder block 11 and the crankcase 12, and an intermediate portion of a substantially triangular lower link 18 is swingable on a pin journal 17b eccentric from the main journal 17a. It is supported by.

  A piston 21 is slidably fitted to a cylinder sleeve 20 provided in the cylinder block 11, and the upper end of an upper link 22 (connecting rod) is pivotally supported by the piston 21 via a piston pin 23. The lower end of 22 is pivotally supported on one end of the lower link 18 via the first pin 24.

  A main journal 25a of a crank-shaped control shaft 25 is pivoted on a lower surface of the crankcase 12 that is offset laterally from the position of the crankshaft 17 by a cap 27 fastened to the crankcase 12 by bolts 26 and 26. Be supported. The control link 28 includes a main body portion 28a and a cap portion 28b fastened to the lower end of the main body portion 28a with bolts 29, 29. The upper end of the main body portion 28a is connected to the other end portion of the lower link 18 via the second pin 30. The pin journal 25b of the control shaft 25 is pivotally supported between the lower end of the main body portion 28a and the cap portion 28b. The control shaft 25 swings within a predetermined angle range by a hydraulic actuator 31 provided at one end thereof.

  An intake port 32 and an exhaust port 33 are opened in a combustion chamber 14a formed on the lower surface of the cylinder head 14, and an intake valve 34 that opens and closes the intake port 32 and an exhaust valve 35 that opens and closes the exhaust port 33 are provided. Is provided. The intake valve 34 is driven to open / close by an intake camshaft 36 via an intake rocker arm 37, and the exhaust valve 35 is driven to open / close by an exhaust camshaft 38 via an exhaust rocker arm 39.

  A secondary balancer device 43 is accommodated between an upper balancer housing 40 fixed to the crankcase 12 below the crankshaft 17 and a lower balancer housing 42 coupled to the lower surface thereof by bolts 41. The secondary balancer device 43 includes a first balancer shaft 44 integrally including a first balancer weight 44a and a second balancer shaft 45 integrally including a second balancer weight 45a. The first balancer shaft 44 is a crank. Driven by a second gear 47 that meshes with a first gear 46 provided on the shaft 17, the second balancer shaft 45 is driven by a fourth gear 49 that meshes with a third gear 48 provided on the first balancer shaft 44. Since the number of teeth of the first gear 46 is set to twice the number of teeth of the second gear 47 and the number of teeth of the third gear 48 and the fourth gear 49 are set to be the same, the first and second balancer shafts 44 and 45 rotate in opposite directions at twice the number of rotations of the crankshaft 17 to suppress secondary vibration of the engine E.

  The secondary balancer device 43 may transmit a driving force from the crankshaft 17 to the first and second balancer shafts 44 and 45 using a chain or a timing belt.

  Next, the operation of the embodiment of the present invention having the above configuration will be described.

  The actuator 31 is driven according to the operating state of the engine E, and the control shaft 25 connected to the actuator 31 rotates to an arbitrary position between the position shown in FIG. 1 and the position shown in FIG. In the position shown in FIG. 1, the pin journal 25 b is positioned below the main journal 25 a of the control shaft 25, so that the control link 28 is pulled down and the lower link 18 is clockwise around the pin journal 17 b of the crankshaft 17. And the upper link 22 is pushed up to raise the position of the piston 21, so that the engine E enters a high compression ratio state.

  On the contrary, in the position shown in FIG. 5, the pin journal 25 b is positioned above the main journal 25 a of the control shaft 25, so that the control link 28 is pushed up and the lower link 18 is centered on the pin journal 17 b of the crankshaft 17. When the upper link 22 is pulled down and the position of the piston 21 is lowered, the engine E is in a low compression ratio state.

  As described above, the control link 28 moves up and down by the swinging of the control shaft 25, the motion constraint condition of the lower link 18 changes, and the stroke characteristics including the top dead center position of the piston 21 change. The compression ratio is arbitrarily controlled.

  FIG. 7 shows waveforms of the secondary vibrations FX and FZ in the XZ plane (a plane orthogonal to the crankshaft 17). The secondary vibration FX in the Z direction and the secondary vibration FX in the X direction are generated simultaneously. It can be seen that the direction of the main secondary vibration is inclined by the angles θ1 and θ2 in the X direction with respect to the Z direction. The direction θ2 of the secondary vibration at the high compression ratio indicated by the solid line and the direction θ2 of the secondary vibration at the low compression ratio indicated by the broken line are shifted by an angle α.

  As shown in FIG. 6, in order to effectively cancel the secondary vibration inclined with respect to the Z direction, the direction of the exciting force generated by the secondary balancer device 43 is inclined by the angle θ with respect to the cylinder axis L1. Just do it. That is, when the phases of the first and second balancer weights 44a and 45a rotating in opposite directions are aligned, the maximum excitation force is generated in the direction of the first and second balancer weights 44a and 45a. By deviating the phase of the first and second lancer weights 44a and 45a by θ with respect to the cylinder axis L1, the direction in which the maximum excitation force is generated is inclined by θ with respect to the cylinder axis L1. . Therefore, the direction of the exciting force generated by the secondary balancer device 43 can be arbitrarily set by simply changing the value of θ.

  However, the angle θ1 at the time of the high compression ratio and the angle θ2 at the time of the low compression ratio are inconsistent. If the angle θ1 that effectively suppresses the secondary vibration at the high compression ratio is adopted, the secondary vibration at the low compression ratio is effective. If the angle θ2 that effectively suppresses the secondary vibration at the low compression ratio is adopted, the secondary vibration at the high compression ratio cannot be effectively suppressed. Therefore, in the present embodiment, the direction in which the first and second balancer weights 44a and 45a generate the maximum excitation force is defined as the direction of the secondary vibration at the high compression ratio θ1 and the direction of the secondary vibration at the low compression ratio. The direction θ is set in the middle of θ2. Specifically, the first and second balancer weights 44a and 45a have the maximum excitation force so that the amplitude of the secondary vibration at the high compression ratio and the amplitude of the secondary vibration at the low compression ratio substantially coincide. The direction θ in which the occurrence occurs is set. Thereby, both the secondary vibration at the time of the high compression ratio and the low compression ratio can be effectively reduced.

  Even if the compression ratio of the engine E is changed, the change in the direction of the secondary vibration of the engine E is suppressed to be extremely small by the secondary balancer device 43, so that the occupant rarely feels uncomfortable due to the change in the operating state of the engine E. I'll do it.

  A thin solid line and a thin broken line in FIG. 8 are waveforms of the secondary vibration FZ when the engine E without the secondary balancer device 43 is at a high compression ratio and a low compression ratio, and a thick solid line and a thick broken line are secondary balancers. It is a waveform of the secondary vibration FZ when the engine E having the device 43 is at a high compression ratio and a low compression ratio. In any case, the secondary vibration FZ is significantly reduced by providing the secondary balancer device 43.

  8A to 8C differ in the direction in which the first and second balancer weights 44a and 45a generate the maximum excitation force. FIG. 8 (A) is set so as to most effectively suppress the secondary vibration at the time of high compression ratio (thick solid line), and the secondary vibration at the time of high compression ratio is sufficiently reduced but low. A considerable amount of secondary vibration (thick broken line) remains at the compression ratio. FIG. 8 (B) is set so as to most effectively suppress the secondary vibration (thick broken line) at the time of the low compression ratio. The secondary vibration at the time of the low compression ratio is sufficiently reduced, but is high. A considerable amount of secondary vibration (thick solid line) remains at the compression ratio. FIG. 8C shows an intermediate setting between the high compression ratio and the low compression ratio (setting of this embodiment). The amplitude of the secondary vibration (thick solid line) at the high compression ratio and the two at the low compression ratio. The amplitude of the next vibration (thick broken line) is reduced to the same magnitude.

Having described the embodiments of the present invention, the present invention is Ru can der to perform various design changes without departing from the spirit and scope thereof.

Vertical section of variable compression ratio engine (high compression ratio state) 2-2 line view of FIG. 3-3 line view of FIG. 4 direction view of FIG. Vertical section of variable compression ratio engine (low compression ratio state) Diagram showing the relationship between the balancer weight phase and the direction of the excitation force Graph showing the direction of secondary vibration of the engine Graph showing the effect of secondary balancer device

Explanation of symbols

14 Engine block
17 Crankshaft
18 Lower link 21 Piston
22 Upper link
25 Control shaft
28 Control link
31 the actuator 43 secondary balancer equipment E engine
L1 Cylinder axis

Claims (2)

The compression ratio of the change the stroke characteristic of the piston (21) in accordance with the operating condition of the engine (E) engine (E), a high compression ratio state the top dead center position of the piston (21) is the top-level A variable stroke characteristic mechanism that changes between the lowest compression ratio state and a secondary balancer device (43) that reduces secondary vibrations of the engine (E) accompanying the reciprocating motion of the piston (21). In the engine vibration elimination device,
The crankshaft (17) of the engine (E) is arranged with the axis of the shaft biased to one side with respect to the cylinder axis (L1),
The variable stroke characteristic mechanism includes an upper link (22) connected to the piston (21), a lower link (18) connected to the upper link (22) and the crankshaft (17), and a lower link (18). A control link (28) having one end connected to the engine block and the other end movably supported by the engine block (14) via the control shaft (25), and an actuator (31) for driving the control shaft (25). And the control shaft (25) and the control link (28) are disposed on the one side with respect to the cylinder axis (L1), so that the secondary balancer device (43) is generated. the direction of force, the downward pressing force is relative to the cylinder axis (L1) directed to one side, upwards Of the excitation force generated by the secondary balancer device (43) is inclined with respect to the cylinder axis (L1) so that the excitation force of direction, midway between the secondary vibration and the direction of the excitation force that obtained by the suppression, the direction of vibrating force said that give suppressing secondary vibration of the low-compression ratio state in the high compression ratio state An engine vibration eliminating device characterized by being set in the direction of. The direction of the excitation force before Symbol secondary balancer device (43) is generated, and the amplitude of the secondary vibration in a high compression ratio state, the amplitude of the secondary vibration in the low compression ratio state becomes substantially equal The engine vibration eliminating device according to claim 1 , wherein the vibration eliminating device is set as described above.

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