JP5998911B2 - Control device for hybrid vehicle - Google Patents

Description

  The present invention relates to a control device for a hybrid vehicle including an engine, an electric motor, and a damper interposed in a power transmission path between the engine and the electric motor.

  A hybrid vehicle that includes an engine, an electric motor, and a damper having a hysteresis mechanism interposed in a power transmission path between the engine and the electric motor is well known. For example, the power transmission device described in Patent Document 1 is an example. In Patent Document 1, a large hysteresis torque is generated in the negative twist region of the damper to which torque is transmitted from the drive wheel side, thereby effectively attenuating sudden torque fluctuations that occur when the engine is started and stopped. It is described. In addition, in the positive twist region of the damper to which torque is transmitted from the engine side, a small hysteresis torque is generated within a twist angle within a predetermined value, thereby effectively attenuating torque fluctuations during steady engine operation. It is described.

JP 2006-029363 A JP 2012-166676 A Japanese Patent Laid-Open No. 2007-216796

  In a damper having a hysteresis mechanism such as the above-mentioned Patent Document 1, if torsional vibration occurs due to vibration or resonance on the output side (drive wheel side) of the drive system during running, a large hysteresis torque is generated. It is preferable to quickly reduce this torsional vibration. However, in the damper described in Patent Document 1, for example, there is a region in which a small hysteresis torque is generated in a state where the damper is twisted in the positive direction. Therefore, even if a torsional vibration occurs during traveling, the large hysteresis torque cannot be used. It may be difficult to quickly reduce torsional vibration.

  The present invention has been made against the background of the above circumstances, and an object thereof is a hybrid including an engine, an electric motor, and a damper interposed between the engine and the electric motor. An object of the present invention is to provide a control device for a hybrid vehicle that can be quickly reduced when torsional vibration occurs during traveling in the vehicle.

To achieve the above object, the gist of the first invention is that: (a) an engine, an electric motor, and a damper having a hysteresis mechanism interposed in a power transmission path between the engine and the electric motor; (B) the hysteresis mechanism is driven from the electric motor toward the engine rather than a hysteresis torque generated by a torsion in a positive direction of the damper that transmits a driving force from the engine toward the electric motor. A control device for a hybrid vehicle having a characteristic that a hysteresis torque generated by torsion in the negative direction of the damper transmitting force is larger, and (c) when the damper is twisted in the positive direction, the power transmission and detecting the torsional vibration of the path performs fuel cut of the engine, by outputting a positive torque from the electric motor, the electric motor Characterized by a state of transmitting a driving force to Rasono engine.

In the damper, when the engine is fuel cut and the driving force is transmitted from the electric motor to the engine, the damper is twisted in the negative direction, and a region where a large hysteresis torque can be generated. Become. Here, when the damper is twisted in the positive direction, it becomes a region where a smaller hysteresis torque is generated than when the damper is twisted in the negative direction, but if a torsional vibration occurs in this state, a large hysteresis torque is generated. Therefore, it is difficult to quickly attenuate the torsional vibration. Therefore, if torsional vibration is detected while the damper is twisted in the positive direction, the engine is fuel cut, positive torque is output from the motor, and the driving force is transmitted from the motor to the engine to rotate the engine. The damper can be switched to a region where large hysteresis torque is generated with the damper twisted in the negative direction. Therefore, this large hysteresis torque can be used for torsional vibration, and torsional vibration can be effectively reduced.

  Preferably, the gist of the second invention is that, in the first invention, in addition to the electric motor, a second electric motor connected to the drive wheel so as to be able to transmit power is provided, and the fuel of the engine During the cutting, a torque for applying a driving force to the driving wheels is output from the second electric motor. In this way, during the fuel cut of the engine, the engine torque transmitted to the drive wheels decreases and the driving force decreases, but the decrease in the driving force is compensated by the torque output from the second electric motor. Thus, the driving force change is suppressed and drivability can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram for explaining a vehicular drive device for a hybrid vehicle to which the present invention is applied, and a schematic configuration diagram that also shows a main part of a control system. It is sectional drawing for demonstrating in detail the structure of the damper apparatus shown in FIG. FIG. 3 is a partially cutaway view of the damper device shown in FIG. 2 as viewed from the direction of arrow A. FIG. 4 is a diagram illustrating the second plate, particularly the periphery of the cantilever, in a more simplified manner in the damper device of FIG. 3. It is a figure which shows the torsion characteristic of the damper apparatus of FIG. 2 is a flowchart for explaining a main part of the control operation of the electronic control device of FIG. 1, that is, a control operation that can quickly reduce the torsional vibration when the torsional vibration is detected during traveling. It is another flowchart explaining the principal part of the control action | operation of the electronic controller which is another Example of this invention, ie, the control action | operation which can reduce the torsional vibration rapidly, if torsional vibration is detected during driving | running | working.

  Here, preferably, the positive torsion of the damper that transmits the driving force from the engine to the electric motor is a torsion when the torque of the engine is transmitted to the electric motor side through the damper, and from the electric motor side. The same torsion occurs when torque in a direction to stop the engine, that is, to reduce the engine rotation speed is transmitted through the damper.

  Further, preferably, the negative twist of the damper that transmits the driving force from the electric motor to the engine means that the torque in the direction of rotating the engine from the electric motor, that is, increasing the engine rotation speed is transmitted through the damper. It is a twist when it is.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following embodiments, the drawings are appropriately simplified or modified, and the dimensional ratios, shapes, and the like of the respective parts are not necessarily drawn accurately.

  FIG. 1 is a schematic configuration diagram illustrating a vehicle drive device 10 of a hybrid vehicle 8 (vehicle 8) to which the present invention is applied. The vehicle drive device 10 includes an engine 24, a power transmission device 12, and a later-described damper 38 provided between the engine 24 and the power transmission device 12. In FIG. 1, in the vehicle drive device 10, in the vehicle 8, the torque of the engine 24 that is a main drive source is transmitted to the wheel-side output shaft 14 via a damper 38 and a planetary gear device 26 described later. Torque is transmitted from the output shaft 14 to the pair of left and right drive wheels 18 via the differential gear device 16. Further, the vehicle drive device 10 is provided with a second electric motor MG2 capable of selectively executing power running control for outputting driving force for traveling and regenerative control for recovering energy. The two electric motor MG2 is connected to the wheel side output shaft via the automatic transmission 22. Accordingly, the output torque transmitted from the second electric motor MG2 to the wheel side output shaft is the speed ratio γs set by the automatic transmission 22 (= the rotational speed Nmg2 of the second electric motor MG2 / the rotational speed Nout of the wheel side output shaft). It is designed to increase or decrease depending on.

  The automatic transmission 22 interposed in the power transmission path between the second electric motor MG2 and the drive wheels 18 is configured to be able to establish a plurality of stages with a gear ratio γs larger than “1”. Since the torque can be increased and transmitted to the wheel-side output shaft during powering to output torque from the second electric motor MG2, the second electric motor MG2 is configured to have a lower capacity or a smaller size. Thereby, for example, when the rotational speed Nout of the wheel side output shaft increases with the high vehicle speed, the second gear ratio γs is reduced to maintain the second motor MG2 in a good state. When the rotational speed Nmg2 of the motor MG2 (hereinafter referred to as the second motor rotational speed) Nmg2 is decreased, or when the rotational speed Nout of the wheel side output shaft is decreased, the gear ratio γs is increased to increase the second motor rotational speed Nmg2. Increase.

  The power transmission device 12 includes a first electric motor MG1 and a second electric motor MG2, and transmits the torque of the engine 24 to the drive wheels 18. The engine 24 is a known internal combustion engine that outputs power by burning fuel such as a gasoline engine or a diesel engine, and is an electronic control device 100 (E-ECU) for engine control (not shown) mainly composed of a microcomputer. Thus, the operation state such as the throttle valve opening, the intake air amount, the fuel supply amount, and the ignition timing is electrically controlled. The electronic control unit 100 includes an accelerator operation amount sensor AS for detecting the operation amount of the accelerator pedal, a brake sensor BS for detecting whether or not the brake pedal is operated, and an engine rotational speed Ne corresponding to the 36 crank angle of the crankshaft. Corresponding to the crank angle sensor 43 for detecting the first motor MG1, the first resolver 44 for detecting the first motor speed Nmg1 of the first motor MG1, the second resolver 46 for detecting the second motor speed Nmg2 of the second motor MG2, and the vehicle speed V. A detection signal is supplied from an output shaft rotational speed sensor 48 that detects the rotational speed Nout of the wheel-side output shaft 14.

  The first electric motor MG1 (electric motor) is, for example, a synchronous motor, and is configured to selectively generate a function as a motor for generating a driving torque Tm1 and a function as a generator, and a battery via an inverter 30. Are connected to a power storage device 32 such as a capacitor. The inverter 30 is controlled by an electronic control device 100 (MG-ECU) (not shown) for controlling the motor generator, which is mainly composed of a microcomputer, so that the output torque Tm1 or the regenerative torque Tm1 of the first electric motor MG1 is adjusted or adjusted. It is set up. The first electric motor MG1 corresponds to the electric motor of the present invention.

  The planetary gear device 26 includes three types of a sun gear S0, a ring gear R0 arranged concentrically with the sun gear S0, and a carrier CA0 that supports the sun gear S0 and the pinion gear P0 meshing with the ring gear R0 so as to rotate and revolve freely. It is a single pinion type planetary gear mechanism that is provided as a rotating element and generates a known differential action. The planetary gear device 26 is provided concentrically with the engine 24 and the automatic transmission 22. Since the planetary gear device 26 and the automatic transmission 22 are configured symmetrically with respect to the center line, the lower half of them is omitted in FIG.

  In the present embodiment, the crankshaft 36 of the engine 24 is connected to the carrier CA0 of the planetary gear device 26 via a damper 38 and a power transmission shaft 39. On the other hand, the first electric motor MG1 is connected to the sun gear S0, and the wheel side output shaft is connected to the ring gear R0. The carrier CA0 functions as an input element, the sun gear S0 functions as a reaction force element, and the ring gear R0 functions as an output element.

  In the planetary gear unit 26, when the reaction torque Tm1 generated by the first electric motor MG1 is input to the sun gear S0 with respect to the output torque of the engine 24 input to the carrier CA0, the ring gear R0 serving as an output element Since direct torque appears, the first electric motor MG1 functions as a generator. Further, when the rotational speed of the ring gear R0, that is, the rotational speed (output shaft rotational speed) Nout of the wheel side output shaft 14 is constant, the rotational speed Nmg1 of the first electric motor MG1 is changed up and down to thereby increase the rotational speed of the engine 24. (Engine speed) Ne can be changed continuously (steplessly).

  The automatic transmission 22 of the present embodiment is constituted by a set of Ravigneaux planetary gear mechanisms. That is, the automatic transmission 22 is provided with a first sun gear S1 and a second sun gear S2. The large diameter portion of the stepped pinion P1 meshes with the first sun gear S1, and the small diameter portion of the stepped pinion P1. Meshes with the pinion P2, and the pinion P2 meshes with the ring gear R1 (R2) disposed concentrically with the sun gears S1 and S2. Each of the pinions P1 and P2 is held by a common carrier CA1 (CA2) so as to rotate and revolve. Further, the second sun gear S2 meshes with the pinion P2.

  The second electric motor MG2 (electric motor) is controlled via the inverter 40 by the electronic control device 100 (MG-ECU) for controlling the motor generator, thereby functioning as an electric motor or a generator, and assist output torque. Alternatively, the regenerative torque is adjusted or set. The second sun gear S2 is connected to the second electric motor MG2, and the carrier CA1 is connected to the wheel side output shaft. The first sun gear S1 and the ring gear R1 constitute a mechanism corresponding to a tuple pinion type planetary gear device together with the pinions P1 and P2, and the second sun gear S2 and the ring gear R1 together with the pinion P2 constitute a single pinion type planetary gear device. The mechanism equivalent to is comprised. The second electric motor MG2 corresponds to the second electric motor of the present invention.

  The automatic transmission 22 includes a first brake B1 provided between the first sun gear S1 and the housing 42, which is a non-rotating member, and a ring gear R1 in order to selectively fix the first sun gear S1. A second brake B2 provided between the ring gear R1 and the housing 42 is provided for selective fixing. These brakes B1 and B2 are so-called friction engagement devices that generate a braking force by a frictional force, and a multi-plate type engagement device or a band type engagement device can be adopted. These brakes B1 and B2 are configured such that their torque capacities change continuously according to the engagement pressure generated by the brake B1 hydraulic actuator such as a hydraulic cylinder and the brake B2 hydraulic actuator, respectively. Yes.

  In the automatic transmission 22 configured as described above, when the second sun gear S2 functions as an input element, the carrier CA1 functions as an output element, and the first brake B1 is engaged, the shift is greater than “1”. When the high speed stage H with the ratio γsh is established and the second brake B2 is engaged instead of the first brake B1, the low speed stage L with the speed ratio γsl larger than the speed ratio γsh of the high speed stage H is established. It is configured. That is, the automatic transmission 22 is a two-stage transmission, and the shift between these shift stages H and L is executed based on the running state such as the vehicle speed V and the required driving force (or accelerator operation amount). More specifically, the shift speed region is determined in advance as a map (shift diagram), and control is performed so as to set one of the shift speeds according to the detected driving state.

  FIG. 2 is a cross-sectional view for explaining the configuration of the damper 38 shown in FIG. 1 in detail. The damper 38 is provided between the engine 24 and the planetary gear device 26 so as to be able to transmit power about the rotation axis C. A power transmission shaft 39 shown in FIG. 1 is splined to the inner periphery of the damper 38. The first electric motor MG1 is connected to the damper 38 via the planetary gear unit 26 so as to be able to transmit power, so that the damper 38 is interposed in the power transmission path between the engine 24 and the first electric motor MG1.

  The damper 38 includes a pair of rotatable disk plates 56 around the rotation axis C, a relatively rotatable hub 58 around the rotation axis C of the disk plate 56, and between the disk plate 56 and the hub 58. A coil spring 62 made of spring steel that is inserted and connected between the disk plate 56 and the hub 58 so as to be able to transmit power, a cushion 63 built in the coil spring 62, and the disk plate 56 and the hub 58. A first hysteresis mechanism 64 that generates a small hysteresis torque H1 between them, and a second hysteresis torque H2 that is provided at the outer peripheral end of the hub 58 and generates a hysteresis torque H2 that is greater than the small hysteresis torque H1 between the disk plate 56 and the hub 58. Torque limiter provided on the outer peripheral side of the hysteresis mechanism 65 and the disk plate 56 And a motor mechanism 68 is configured comprise. The first hysteresis mechanism 64 and the second hysteresis mechanism 65 constitute the hysteresis mechanism of the present invention.

  The disk plate 56 includes a pair of left and right disk-shaped first disk plates 70 (hereinafter referred to as first plates 70) and a second disk plate 72 (hereinafter referred to as second plates 72). With the plates 70 and 72 sandwiched in the axial direction, the outer peripheral portions are fastened together by a rivet 66 so that they cannot rotate relative to each other. The rivet 66 also functions as a fastening member for a lining plate 76 that is a component part of a torque limiter mechanism 68 described later. In the first plate 70, a plurality of first opening holes 70a for accommodating the coil springs 62 are formed in the circumferential direction. Also, the second plate 72 is formed with a plurality of second opening holes 72a for accommodating the coil springs 62 in the circumferential direction at positions corresponding to the first opening holes 70a. A plurality of coil springs 62 are accommodated at equiangular intervals in a space formed by the first opening hole 70a and the second opening hole 72a. Thus, when the disk plate 56 rotates around the rotation axis C, the coil spring 62 is similarly revolved around the rotation axis C. A cylindrical cushion 63 is built in each coil spring 62.

  The hub 58 includes a cylindrical portion 58a having inner peripheral teeth on which the power transmission shaft 39 is spline-fitted on the inner peripheral portion, and a disk-shaped flange portion 58b extending radially outward from the outer peripheral surface of the cylindrical portion 58a. , And a plurality of projecting portions 58c projecting radially outward from the flange portion 58b. And the coil spring 62 is inserted in the space formed between each protrusion part 58c in a rotation direction. Thus, when the hub 58 rotates around the rotation axis C, the coil spring 62 is similarly revolved around the rotation axis C. With this configuration, the coil spring 62 transmits power while being elastically deformed according to the amount of relative rotation between the members of the disk plate 56 and the hub 58. For example, when the disk plate 56 rotates, one end of the coil spring 62 is pressed, and the other end of the coil spring 62 presses the protrusion 58c of the hub 58, whereby the hub 58 is rotated. At this time, the coil spring 62 transmits power while being elastically deformed, so that a shock due to torque fluctuation is absorbed by the coil spring 62.

  The first hysteresis mechanism 64 is provided on the inner peripheral side of the coil spring 62 and between the disc plate 56 and the flange portion 58b of the hub 58 in the axial direction. The hysteresis mechanism 64 includes a first member 64a that is interposed between the first plate 70 and the flange portion 58b, and a second member that is interposed between the second plate 72 and the flange portion 58b. 64b and a disc spring 64c that is inserted between the second member 64b and the second plate 72 in a preloaded state and presses the second member 64b toward the flange portion 58b. Note that a part of the first member 64 a is fitted into a notch formed in the first plate 70, thereby preventing relative rotation of the first member 64 a and the first plate 70. Further, a part of the second member 64 b is fitted into a notch formed in the second plate 72, so that the relative rotation of the second member 64 b and the second plate 72 is prevented. In the first hysteresis mechanism 64 configured as described above, when the hub 58 and the disk plate 56 slide, a frictional force is generated between the flange portion 58b and the first plate 70 and the second plate 72. As a result, hysteresis torque is generated. The first hysteresis mechanism 64 is designed such that a relatively small small hysteresis torque H1 (small hiss) is generated in the positive side region and the negative side region of the torsion angle. The small hysteresis torque H1 is advantageous when a torsional vibration having a relatively small amplitude that occurs during idling or steady engine operation is attenuated. However, the small hysteresis torque H1 has a small vibration suppressing effect when, for example, torsional vibration or resonance occurs from the drive wheel side.

  The torque limiter mechanism 68 is provided on the outer peripheral side of the disk plate 56, and has a function of preventing torque transmission exceeding a preset limit torque Tlim. The torque limiter mechanism 68 is fastened with a rivet 66 together with the disk plate 56, and rotates with the disk plate 56, and a support that is arranged on the outer peripheral side and is rotatable around the rotation axis C. A plate 78, a disk-shaped pressure plate 80 disposed on the inner peripheral side of the support plate 78 and rotatable around the rotation axis C, and a first plate interposed between the pressure plate 80 and the lining plate 76; The friction material 81, the second friction material 82 inserted between the lining plate 76 and the support plate 78, and the cone shape inserted between the pressure plate 80 and the support plate 78 in a preloaded state. The disc spring 83 is included.

  The support plate 78 includes a disk-shaped first support plate 78a and a disk-shaped second support plate 78b, and a bolt (not shown) for fixing a flywheel (not shown) and the support plates 78a, 78b to the outer periphery thereof. Fastening bolt holes are respectively formed. A space is formed between the first support plate 78a and the second support plate 78b by bending the inner periphery of the first support plate 78a in the axial direction. In this space, a disc spring 83, a pressure plate 80, a first friction material 81, a lining plate 76, and a second friction material 82 are sequentially accommodated in the axial direction from the first support plate 78a to the second support plate 78b. ing.

  The lining plate 76 is an annular plate member whose inner peripheral portion is fixed together with the first plate 70 and the second plate 72 by a rivet 66. Similarly, the pressure plate 80 is formed in an annular plate shape. A first friction material 81 is interposed between the pressure plate 80 and the lining plate 76. The first friction material 81 is formed in an annular plate shape, for example. Alternatively, they may be formed in an arc shape (piece shape) and arranged side by side at equal angular intervals in the circumferential direction. The first friction material 81 is attached to the lining plate 76 side, but may be attached to the pressure plate 80 side.

  A second friction material 82 is inserted between the inner peripheral portion of the second support plate 78 b and the lining plate 76. Similar to the first friction material 81, the second friction material 82 is formed in, for example, an annular plate shape. Alternatively, they may be formed in an arc shape (piece shape) and arranged side by side at equal angular intervals in the circumferential direction. The second friction material 82 is attached to the lining plate 76 side, but may be attached to the second support plate 78b side.

  A disc spring 83 is inserted between the first support plate 78a and the pressure plate 80 in a preloaded state. The disc spring 83 is formed in a cone shape, and its inner peripheral end abuts on the pressure plate 80 and its outer peripheral end abuts on the first support plate 78a to generate the preload (the disc spring load W). The amount of deflection is changed and inserted. Accordingly, the disc spring 83 presses the pressure plate 80 in the axial direction with the disc spring load W toward the lining plate 76 side. The friction coefficient μ of the friction surface between the pressure plate 80 and the first friction material 81 and the friction surface between the second support plate 78b and the second friction material 82, the working radius r of the friction materials 81 and 82, By adjusting the disc spring load W of the disc spring 83, the limit torque Tlm is set to a target value. When a torque exceeding the limit torque Tlm is input to the torque limiter mechanism 68, the friction surface between the pressure plate 80 and the first friction material 81, and between the second support plate 78b and the second friction material 82 are displayed. Thus, slip occurs on the friction surface, and torque transmission exceeding the limit torque Tlm is prevented.

  The second hysteresis mechanism 65 is provided on the outer periphery of the hub 58 and the disk plate 56, and generates a sliding resistance (friction force) between them, thereby generating a small hysteresis torque H1 generated by the first hysteresis mechanism 64. This is a mechanism for generating a larger hysteresis torque H2. FIG. 3 is a partially cutaway view of the damper 38 of FIG. 2 as viewed from the direction of arrow A. A part of FIG. 3 is shown in a perspective view. As shown in FIGS. 2 and 3, a rectangular (piece-shaped) friction made of, for example, a resin material is provided on the outer peripheral side of the protrusion 58 c of the hub 58 and on both surfaces substantially parallel to the disk plate 56. A plate 90 is fixed by a rivet 92.

  Further, as shown in FIG. 3, the second plate 72 has an L-shape extending from the outer peripheral end portion toward the inner peripheral side and further formed from the inner peripheral portion along the circumferential direction (rotation direction). A notch 94 is formed. By forming the notch 94, the second plate 72 is formed with a fan-shaped cantilever portion 96 parallel to the rotation direction. The cantilever part 96 is formed in the same position as the site | part to which the friction plate 90 of the protrusion part 58c is fixed in radial direction. Further, the cantilever portion 96 is formed in a tapered shape with a predetermined gradient S toward the hub 58 side (the friction plate 90 side) along the rotation direction. Therefore, when the hub 58 and the second plate 72 are rotated relative to each other, the friction plate 90 and the cantilever portion 96 come into contact with each other and start to slide in parallel with the compression of the coil spring 62. Although not shown in FIG. 3, the first plate 70 shown in FIG. 2 is also provided with a cantilever 98 having the same shape as the second plate 72.

  FIG. 4 is a diagram showing the second plate 72 particularly in the vicinity of the cantilever portion 96 in the damper 38 shown in FIG. Note that the second plate 72 actually has a disk shape, but in FIG. 4, the second plate 72 is developed in a straight line. Accordingly, the protruding portion 58c of the hub 58 indicated by a broken line also moves in a straight line (right and left direction in FIG. 4) in FIG. 4 although it actually rotates around the rotation axis C. 4 is a side view of the cantilever part 96 and the protruding part 58c shown below. In FIG. 4, the friction plate 90 fixed to the protruding portion 58c is omitted.

  As can be seen from the side view of FIG. 4, the cantilever portion 96 is inclined at a predetermined gradient S. Therefore, when the protrusion 58c (hub 58) and the second plate 72 are relatively rotated and the protrusion 58c contacts the cantilever 96, the protrusion 58c and the second plate 72 are slid. Specifically, in FIG. 4, when the protrusion 58 c moves relative to the left side with respect to the second plate 72, the protrusion 58 c and the cantilever are related to the fact that the cantilever 96 is formed in a tapered shape. 96 abut on each other, and the hub 58 is slid against each other while pressing the cantilever 96 according to the change of the twist angle θ. 3 and 4 show the cantilever portion 96 of the second plate 72, the cantilever portion 98 of the first plate 70 is also slid in the same manner.

  As described above, when the projecting portion 58c and the cantilever portions 96, 98 are slid, a frictional force is generated between the friction plate 90 fixed to the projecting portion 58c and the cantilever portions 96, 98. Accordingly, a hysteresis torque H2 is generated. That is, the cantilever portions 96 and 98 have both functions of a disc spring and a sliding member in the conventional hysteresis mechanism. This hysteresis torque H2 includes the thickness of the friction plate 90 and the hub 58, the gap between the first plate 70 and the second plate 72, the notch shape formed in the first plate 70 and the second plate 72, and the first plate 70. Further, the target hysteresis torque H2 is set by adjusting the gradient S (taper angle) of the cantilever portions 96 and 98 of the second plate 72 and adjusting the pressing load to the friction plate 90. Further, since the second hysteresis mechanism 65 is disposed on the outer peripheral side in the radial direction with respect to the first hysteresis mechanism 64, the hysteresis torque H2 larger than the small hysteresis torque H1 can be easily generated. In addition, by adjusting the notch shape and the gradient S of the cantilever portions 96 and 98, the torsion angle θ at which the hysteresis torque H2 is generated can be appropriately adjusted.

  Here, in the second hysteresis mechanism 65 of the present embodiment, when torque (driving force) acting in the direction of rotating the engine 24 (in the direction of increasing engine rotation speed) is transmitted from the first electric motor MG1 toward the engine 24. In this state, the damper 38 is twisted in the negative direction (negative side). In this state, the hysteresis torque H2 is set to be generated. That is, the friction plate 90 is set to slide with the cantilever portions 96 and 98 when the torque Tmg1 acting in the direction of rotating the engine 24 is transmitted from the first electric motor MG1. On the other hand, when the damper 38 to which torque (driving force) is transmitted from the engine side is twisted in the positive direction (positive side), the friction plate 90 and the cantilever portions 96 and 98 are set so as not to slide. Yes. That is, the hysteresis torque H2 is set not to be generated when the damper is twisted in the positive direction (positive side).

  For example, in FIG. 3, when the torque that turns the engine 24 is transmitted from the first electric motor MG1 to the engine 24 and the damper 38 is twisted to the negative side, the hub 58 rotates counterclockwise (FIG. 4). In this case, the cantilever 96 and the friction plate 90 are slid in accordance with the change in the twist angle θ. Therefore, in the torsional angle region where the torque (driving force) in the engine rotation direction is transmitted from the first electric motor MG1 to the engine 24 and the damper 38 is twisted to the negative side, the hysteresis torque H2 is generated by the second hysteresis mechanism 65. To do. On the other hand, when torque is transmitted from the engine 24 toward the driving wheel and the damper 38 is twisted to the positive side, the hub 58 rotates clockwise (the protrusion 58c moves to the right in FIG. 4). Then, since the friction plate 90 is separated from the cantilever part 96, the cantilever part 96 and the friction plate 90 do not slide even if the twist angle θ changes. Therefore, in the torsional angle region where the torque (driving force) is transmitted from the engine side to the driving wheel side and the damper 38 is twisted to the positive side, the hysteresis torque H2 by the second hysteresis mechanism 65 is not generated.

  FIG. 5 shows the torsional characteristics of the damper 38 of this embodiment. The horizontal axis represents the twist angle θ (rad) of the damper 38, and the vertical axis represents the torque (Nm). As shown in FIG. 5, the first hysteresis mechanism 64 functions in the torsion angle region where the torsion angle θ is positive (positive side), that is, the region in which torque (driving force) is transmitted from the engine side. H1 is generated. On the other hand, since the second hysteresis mechanism 65 functions together with the first hysteresis mechanism 64 in the torsion angle region where the torsion angle θ is negative, that is, the region where torque is transmitted from the first motor side to the engine side, the small hysteresis torque H1 And a large hysteresis torque (H1 + H2) that is the sum of the hysteresis torque H2 and the hysteresis torque H2. Thus, the small hysteresis torque H1 generated by the torsion in the positive direction (positive side) of the damper 38 that transmits the driving force from the engine 24 toward the first electric motor MG1 is directed toward the engine 24 from the first electric motor MG1. The large hysteresis torque (H1 + H2) generated by the torsion in the negative direction of the damper 38 that transmits the driving force in the direction of rotating the engine 24 is set to be larger.

  Here, in the hybrid vehicle 8 of the present embodiment, when positive torque is output from the first electric motor MG1, the differential action of the planetary gear unit 26 acts in the direction of rotating (driving) the engine 24 toward the engine 24 side. Torque is transmitted. Accordingly, in the damper 38, when a positive torque is output from the first electric motor MG1, the damper 38 is twisted to the negative side. That is, this is a region where large hysteresis torque is generated. On the other hand, when negative torque is output from the first electric motor MG1, torque acting in the direction in which the engine 24 is stopped (rotation decreasing direction) is transmitted to the engine 24 side by the differential action of the planetary gear device 26. Accordingly, in the damper 38, when negative torque is output from the first electric motor MG1, the damper 38 is twisted to the positive side. That is, this is a region where a small hysteresis torque is generated.

  In the hybrid vehicle 8 including the damper 38 configured as described above, a region in which a small hysteresis torque is generated when the damper 38 is twisted to the positive side. In such a traveling state, if a large torsional vibration occurs in the power transmission path between the engine 24 and the driving wheel 18 due to vibration or resonance from the driving wheel 18 side, the large hysteresis torque cannot be used, so that the torsional vibration is promptly reduced. It will be difficult to reduce it. Further, due to this, a load on each component constituting the power transmission device 12 becomes large, and there is a problem that durability of each component is lowered. Therefore, when the electronic control unit 100 detects torsional vibration during traveling with the damper 38 being twisted in the positive direction (positive side), the electronic control unit 100 controls the engine 24 and the first electric motor MG1 so that the damper 38 has a large hysteresis torque. By switching to an available state, control is performed to quickly reduce torsional vibration. Hereinafter, control for reducing torsional vibration by the electronic control unit 100 will be described.

  Returning to FIG. 1, the electronic control unit 100 includes a so-called microcomputer having a CPU, a RAM, a ROM, an input / output interface, and the like, for example. Various controls of the vehicle 8 are executed by performing signal processing according to the stored program. For example, the electronic control unit 100 executes output control of the engine 24, drive control and regenerative control of the first electric motor MG1 and second electric motor MG2, shift control of the automatic transmission 22, and the like. Accordingly, it is configured separately for engine control, motor control, hydraulic control (shift control), and the like. The electronic control device 100 also functions as a torsional vibration detection unit 102 that detects torsional vibrations, a torsional vibration reduction unit 104 that quickly reduces detected torsional vibrations, and a driving force correction unit 106, which are the main parts of the present invention. Is prepared.

  The torsional vibration detection unit 102 is a means for detecting torsional vibration that occurs during traveling. For example, when the vehicle 8 travels on a bad road such as a wavy road and the drive wheel 18 undergoes rotational fluctuation, when a surge occurs during traveling, or when resonance occurs in the drive device 10, Torsional vibration is generated. Therefore, the torsional vibration detection unit 102 sequentially detects the second rotational speed Nmg2 of the second electric motor MG2 by the second resolver 46, and sequentially extracts the rotational fluctuation component ss (variation component ss) of the second rotational speed Nmg2. Note that the extraction of the rotation fluctuation component ss is a well-known technique, and thus the description thereof is omitted. Further, the torsional vibration detection unit 102 sequentially calculates the fluctuation integrated value S by integrating the absolute value of the extracted fluctuation component ss in the predetermined period Ta before the current time point. The predetermined period Ta is set to a time corresponding to one cycle of the fluctuation component ss, for example. Then, the torsional vibration detection unit 102 determines whether or not the sequentially calculated fluctuation integrated value S exceeds a predetermined value α, and if the fluctuation integrated value S exceeds the predetermined value α, the torsional vibration is detected. Is determined to have occurred. The predetermined value α is a value that is adapted experimentally or design in advance, and is a threshold value for determining the occurrence of torsional vibration.

  When the torsional vibration is detected, the torsional vibration reducing unit 104 switches to a region where large hysteresis torque can be generated by switching the damper 38 to the negative side by performing control described below. The torsional vibration reduction unit 104 first performs a so-called fuel cut that stops the fuel supply to the engine 24. As a result, no torque (driving force) is output from the engine 24.

  Further, the torsional vibration reduction unit 104 outputs a positive torque from the first electric motor MG1. As a result, torque acting in the engine rotation direction is transmitted from the first electric motor MG1 to the engine 24 through the planetary gear unit 26, and the engine 24 is rotated (motoring mode). The state is twisted to the negative side, and the region is switched to the region where the large hysteresis torque shown in FIG. Therefore, since a large hysteresis torque is generated with respect to torsional vibration, the amount of vibration energy absorbed by the hysteresis torque increases, and the torsional vibration is quickly reduced (damped). Further, since the torsional vibration is reduced, the load related to the components constituting the drive device 10 is also reduced, and the durability of the components is prevented from being lowered. When switching to a state where the damper 38 is twisted to the negative side, the damper 38 is twisted to the negative side not to the region of the location A shown in FIG. 5 but to the region of about the location B where the large hysteresis torque can be fully utilized. Thus, the torque of the first electric motor MG1 is controlled.

  Here, during the execution of the torsional vibration reduction unit 104, the fuel cut of the engine 24 is executed, so that no torque is output from the engine 24, and the driving force transmitted to the drive wheels 18 is reduced. On the other hand, the driving force correction unit 106 outputs the torque that gives the driving force to the driving wheel 18 from the second electric motor MG2 that is coupled to the driving wheel 18 so that the power can be transmitted, thereby preventing the driving force from decreasing. To do. The driving force correction unit 106 calculates the torque Tmg2 of the second electric motor MG2 that can cover the decrease in driving force due to the fuel cut of the engine 24, and outputs the calculated torque Tmg2 from the second electric motor MG2. When torque is already output from the second electric motor MG2 before execution of the torsional vibration reduction unit 104, in addition to the torque, torque that covers the decrease in the driving force is further output. As a result, the driving force decrease when the torsional vibration reduction unit 104 is executed is corrected by the driving force correction unit 106, and changes in the vehicle behavior due to the driving force reduction in the torsional vibration reduction unit 104 are suppressed.

  FIG. 6 is a flowchart for explaining a main part of the control operation of the electronic control unit 100, that is, a control operation that can quickly reduce the torsional vibration when the torsional vibration is detected during traveling. For example, about several msec to several tens msec. It is repeatedly executed with a very short cycle time.

  First, in step S1 (hereinafter, step is omitted) corresponding to the torsional vibration detection unit 102, the first motor rotation speed Nmg1 (motor rotation speed) of the first motor MG1 is input. Next, in S2 corresponding to the torsional vibration detection unit 102, the fluctuation integrated value S is calculated by integrating the fluctuation component ss sequentially extracted in the predetermined period Ta. Then, in S3 corresponding to the torsional vibration detection unit 102, it is determined whether or not the calculated fluctuation integrated value S exceeds a preset predetermined value α. If S3 is negative, the routine is terminated. On the other hand, when S3 is affirmed, the fuel cut of the engine 24 is executed in S4 corresponding to the torsional vibration reduction unit 104. At the same time, in S5 corresponding to the torsional vibration reduction unit 104, the damper 38 is switched to the motoring mode of the engine 24 that outputs a positive torque acting in the direction of rotating the engine 24 from the first electric motor MG1. Is switched to a negative twisted state. Therefore, the damper 38 becomes an operation region where a large hysteresis torque can be generated, and the torsional vibration can be quickly reduced by the large hysteresis torque. In addition, at S6 corresponding to the driving force correction unit 106, the reduction in driving force due to the fuel cut of the engine 24 is corrected by the torque of the second electric motor MG2, thereby changing the vehicle behavior due to the reduction in driving force. It is suppressed.

  As described above, in the damper 38, when the engine 24 is in a fuel cut state and the driving force is transmitted from the first electric motor MG1 to the engine 24, the damper 38 is twisted in the negative direction. This is a region where large hysteresis torque (H1 + H2) can be generated. Here, when the damper 38 is twisted in the positive direction, it becomes a region where a small hysteresis torque H1 is generated that is smaller than the state in which it is twisted in the negative direction. Since no torque is generated, it is difficult to quickly attenuate the torsional vibration. Therefore, when torsional vibration is detected in a state where the damper 38 is twisted in the forward direction, the fuel cut of the engine 24 is performed, and the driving force is transmitted from the first electric motor MG1 to the engine 24 to rotate the engine. 38 can be switched to a region where a large hysteresis torque is generated in a state twisted in the negative direction. Therefore, a large hysteresis torque can be used for torsional vibration, and torsional vibration can be effectively reduced.

  Further, according to the present embodiment, the second electric motor MG2 that applies driving force to the drive wheels 18 is provided, and the torque Tmg2 is output from the second electric motor MG2 during the fuel cut of the engine 24. In this way, during the fuel cut of the engine 24, the engine torque Te transmitted to the drive wheels 18 decreases and the drive force decreases, but the decrease in the drive force is output from the second electric motor MG2. By supplementing with Tmg2, the driving force change is suppressed and drivability can be improved.

  Next, another embodiment of the present invention will be described. In the following description, parts common to those in the above-described embodiment are denoted by the same reference numerals and description thereof is omitted.

  In the above-described embodiment, the occurrence of torsional vibration is determined by detecting rotational fluctuations that occur when traveling on rough roads such as wavy roads. Torsional vibration is caused by misfire of the cylinders of the engine 24. It also occurs when 24 torque fluctuations occur. Therefore, the torsional vibration detection unit 110 of the present embodiment detects the occurrence of torsional vibration by detecting misfire of the engine 24.

  First, the torsional vibration detection unit 110 sequentially calculates a time required for 30 degrees T30 (hereinafter, time T30) required for the crankshaft 36 of the engine 24 to rotate 30 degrees. The calculation of time T30 is based on the crank angle from the crank angle sensor, and the time at that time is detected every time the crank angle rotates 30 degrees, and the time detected this time and the previous crank angle rotated 30 degrees. It is calculated by taking the difference from the time.

  Next, the torsional vibration detection unit 110 calculates a 720-degree difference Δ720 of the calculated time T30. The 720 degree difference Δ720 of the time T30 is calculated by taking the difference between the current time T30 and the time T30 720 degrees before this time. Further, the torsional vibration detection unit 110 calculates a 360-degree difference Δ360 of the calculated time T30. The 360 degree difference Δ360 of the time T30 is calculated by taking the difference between the current time T30 and the time T30 360 degrees before this time. Further, the torsion time detection unit 110 calculates a 120-degree difference Δ120 of the calculated time T30. This 120-degree difference Δ120 is calculated by taking the difference between the current time T30 and the time T30 120 degrees before this time.

  Then, the torsional vibration detection unit 110 determines whether or not the calculated 720-degree difference Δ720 exceeds a preset threshold A, and whether the calculated 360-degree difference Δ360 exceeds a preset threshold B. Then, it is determined whether or not the calculated 120-degree difference Δ120 exceeds a preset threshold value C. Each of the threshold values A, B, and C is a value that can determine misfire of the engine 24 when the threshold value corresponding to each of the differences Δ720, Δ360, and Δ120 is exceeded, and is a value that is adapted in advance through experiments and design. For example, when at least one of a condition that the 720 degree difference Δ720 does not exceed the threshold A, a condition that the 360 degree difference Δ360 does not exceed the threshold B, and a condition that the 120 degree difference Δ120 does not exceed the threshold C is satisfied. It is determined that no misfire has occurred. On the other hand, if the 720 degree difference Δ720 exceeds the threshold A, the 360 degree difference Δ360 exceeds the threshold B, and the 120 degree difference Δ120 exceeds the threshold C, it is determined that the engine 24 has misfired. The When the torsional vibration detection unit 110 determines that the engine 24 has misfired, the torsional vibration detection unit 110 determines that torsional vibration has occurred due to torque fluctuation due to the misfire.

  FIG. 7 is a flowchart for explaining a main part of the control operation of the electronic control apparatus 100 according to another embodiment of the present invention, that is, a control operation that can quickly reduce the torsional vibration when the torsional vibration is detected during traveling.

  In FIG. 7, in S11 corresponding to the torsional vibration detector 110, a time T30 required for the crankshaft 36 to rotate 30 degrees is input. Next, in S12 corresponding to the torsional vibration detection unit 110, a 720-degree difference Δ720 at time T30, a 360-degree difference Δ360 at time T30, and a 120-degree difference Δ120 at time T30 are calculated. In S13 corresponding to the torsional vibration detection unit 110, whether the calculated 720 degree difference Δ720 exceeds the threshold A, whether the calculated 360 degree difference Δ360 exceeds the threshold B, whether the calculated 120 degrees is 120 degrees. It is determined whether or not the difference Δ120 exceeds the threshold value C. If at least one of these is denied, that is, if any difference does not exceed the threshold value, S13 is denied and the present routine is terminated. On the other hand, if all of these are affirmed, that is, if all the differences exceed the threshold value, the fuel cut of the engine 24 is executed in S4 corresponding to the torsional vibration reduction unit 104. At the same time, in S5 corresponding to the torsional vibration reduction unit 104, the damper 38 is switched to the motoring mode of the engine 24 that outputs a positive torque acting in the direction of driving the engine 24 from the first electric motor MG1. Is switched to a negative twisted state. Therefore, the damper 38 becomes an operation region where a large hysteresis torque can be generated, and the torsional vibration can be quickly reduced by the large hysteresis torque. In addition, at S6 corresponding to the driving force correction unit 106, the reduction in driving force due to the fuel cut of the engine 24 is corrected by the torque of the second electric motor MG2, thereby changing the vehicle behavior due to the reduction in driving force. It is suppressed.

  As described above, the torsional vibration detection unit 110 of the present embodiment can also detect the torsional vibration caused by the misfire of the engine 24, and by executing the torsional vibration reduction unit 104 and the driving force correction unit 106, The same effects as those in the previous embodiment can be obtained.

  As mentioned above, although the Example of this invention was described in detail based on drawing, this invention is applied also in another aspect.

  For example, the first embodiment and the second embodiment described above are not necessarily performed separately, and may be performed in combination.

  In the above-described embodiment, in the hybrid vehicle 8, the first electric motor MG1 is connected to the damper 38 and the engine 24 via the planetary gear unit 26, but the engine 24 and the first electric motor MG1 are connected via a clutch. Or a structure that is directly connected. That is, the present invention can be appropriately applied to any hybrid vehicle having a configuration in which the damper 38 is interposed in the power transmission path between the engine 24 and the first electric motor MG1.

  In the above-described embodiment, the predetermined period Ta for calculating the fluctuation integrated value S is set to one cycle of the fluctuation component ss. However, the present invention is not necessarily limited to this, for example, the second electric motor of the second electric motor MG2. You may change suitably, such as changing according to rotation speed Nmg2.

  In the above-described embodiment, the fluctuation integrated value S may be a value obtained by removing a noise component that deviates from a predetermined frequency from the fluctuation integrated value S using a low-pass filter or a high-pass filter.

  In the above-described embodiment, the fluctuation component is extracted based on the second motor rotation speed Nmg2 of the second electric motor MG2. However, the fluctuation component may be extracted based on the rotation speed Nout of the wheel side output shaft 14. I do not care.

  In the above-described embodiment, steps S4 to S6 in FIGS. 6 and 7 are executed substantially simultaneously, and the control order is not limited to this.

  In the above-described embodiment, the damper 38 includes the first hysteresis mechanism 64 and the second hysteresis mechanism 65 to realize the torsional characteristics as shown in FIG. The structure is not limited to this. That is, the specific mechanism is not particularly limited as long as the damper has the torsional characteristics shown in FIG.

  In the above-described embodiment, a large hysteresis torque is uniformly generated when the damper 38 has a negative torsion angle. For example, even in a structure in which a small hysteresis torque is generated in a small torsion angle region. I do not care.

  In the above-described embodiment, the automatic transmission 22 is provided. However, the specific structure of the transmission is not limited to the automatic transmission 22 alone. For example, a multistage transmission or a belt-type transmission is used. A step transmission or the like can be changed as appropriate. Further, the transmission may be omitted.

  Further, the detection direction of the torsional vibration by the torsional vibration detection units 102 and 110 is an example, and the present invention can be appropriately applied even when the torsional vibration is detected in another direction.

  In the above-described embodiment, the first motor MG1 is connected to the engine 24 via the planetary gear device 26, and when the first motor MG1 outputs a positive torque, the damper 38 is twisted to the negative side, and the first motor MG1. Is output to a negative torque, the damper 38 is twisted to the positive side, but is not necessarily limited thereto. A structure in which the damper is twisted to the positive side when the electric motor outputs a positive torque and the damper is twisted to the negative side when the negative torque is output may be employed.

  The above description is only an embodiment, and the present invention can be implemented in variously modified and improved forms based on the knowledge of those skilled in the art.

8: Hybrid vehicle 18: Drive wheel 24: Engine 38: Damper 64: First hysteresis mechanism (hysteresis mechanism)
65: Second hysteresis mechanism (hysteresis mechanism)
100: Electronic control device (control device)
MG1: First motor (motor)
MG2: second electric motor (second electric motor)

Claims (2)

In a hybrid vehicle comprising an engine, an electric motor, and a damper having a hysteresis mechanism interposed in a power transmission path between the engine and the electric motor,
The hysteresis mechanism is configured such that the hysteresis of the damper that transmits the driving force from the motor to the engine is less than the hysteresis torque that is generated by the twist in the positive direction of the damper that transmits the driving force from the engine to the motor. A control device for a hybrid vehicle having a characteristic that a hysteresis torque generated by twisting in a direction is larger,
When torsional vibration of the power transmission path is detected when the damper is twisted in the positive direction, the engine performs fuel cut and outputs a positive torque from the motor , thereby generating driving force from the motor to the engine. A control device for a hybrid vehicle, characterized by being in a state of transmission. In addition to the electric motor, a second electric motor connected to the drive wheel so as to be able to transmit power is provided.
2. The hybrid vehicle control device according to claim 1, wherein during the fuel cut of the engine, a torque for applying a driving force to the drive wheels is output from the second electric motor.

Images