JP3900134B2 - Mode change control device for hybrid transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To surely restrict a shock when changing mode with torque assist by a motor/generator when changing mode between two kinds of continuous shifting ratio modes. <P>SOLUTION: At a moment t1 when the number of revolution N2 of a second motor/generator MG 2 is lowered to N2cl, namely, at a shifting ratio lower than the synchronous point wherein power passing through the motor/generator in both modes become zero, high-clutch is started to be connected by raising a target oil pressure Pcl*. Connection of the high-clutch generates lowering (d) of the output torque To like a solid line shows, and in order to prevent the lowering, the assist torque T1assist* and T2assist* corresponding to Pcl* and the engine torque are commanded to both the motor/generator since t1 to the moment t2 when N2 is lowered to the N2brk to start to release low brake with lowering of the target oil pressure Pbrk*, and the assist torque T1assist * and T2assist* corresponding to Pcl*, Pbrk* and the engine torque are commanded to both the motor/generator since the moment t2 to a mode selection completing time t3 when N2 becomes N2*, and drop of the output torque To can be thereby restricted. <P>COPYRIGHT: (C)2005,JPO&amp;NCIPI

Description

  The present invention relates to a mode switching control device for a hybrid transmission, and more particularly to a mode switching control device for appropriately performing mode switching between two types of continuously variable transmission ratio modes.

Conventionally, a hybrid transmission having two types of shift modes has an engine and two motors / generators as described in, for example, Patent Document 1, and two modes are realized by switching between fastening and release of fastening elements. A two-mode composite split type electromechanical transmission has been proposed.
JP 2000-062483 A

In such a two-mode composite split type electromechanical transmission, when the mode is switched between the two modes, the driving force changes due to the interaction with the motor / generator having a large inertia when the fastening element is fastened or released. Occurs and the mode switching shock tends to increase.
However, Patent Document 1 does not propose a countermeasure technique for reducing the driving force change (mode switching shock) that occurs at the time of the mode switching, and cannot completely eliminate the concern that this shock may be uncomfortable.

On the other hand, the applicant of the present application is developing and proposing the following as a hybrid transmission having two types of modes.
This hybrid transmission
Comprising first, second, and third differentials that determine the rotational state of the two elements and determine the rotational state of the other elements;
One element of the first and second differential devices is coupled to each other, and one element of the first and second differential devices excluding these elements is connected to each other by a third differential device;
The engine, output shaft, and two motors / generators are coupled to the components of the first and second differential units including the above elements, and the correlation between these engines, the output shaft, and the two motors / generators is correlated. Let
The direction in which the rotational speeds of the elements of the first and second differential units connected to each other by the third differential unit approach or move away from each other, obtained by fastening a brake that fixes one element of the third differential unit The first and second differential gears connected to each other by the third differential gear, which are obtained by engaging the first shift mode that can be changed to and the clutch that mutually couples the two elements of the third differential gear. The above-described elements have two types of continuously variable transmission ratio modes including a second transmission mode in which the elements can rotate integrally.

Also in such a hybrid transmission, since the mode switching between the two types of continuously variable transmission ratio modes is performed by switching between the brake and the clutch, the mode is controlled by the interaction with the motor / generator, engine, and output shaft having a large inertia. A shock due to a change in driving force occurs during switching.
Therefore, the hybrid transmission under development proposed by the applicant of the present application is also required to take a mode switching shock mitigation measure. However, as described above, there has been no technology for mitigating the shock associated with mode switching as described above. There was no way to reduce the mode change shock of the hybrid transmission.

  In the hybrid transmission under development proposed by the applicant of the present invention, the torque sharing of one motor / generator is reduced at the time of mode switching. From the standpoint that mode switching shock can be reduced by torque assist by a motor / generator, it is an object to propose a mode switching control device for a hybrid transmission that embodies this idea and solves the above-mentioned problems related to mode switching shock. To do.

For this purpose, the mode switching control device according to the present invention is as described in claim 1,
Based on the gist configuration as a basic premise of the above hybrid transmission under development proposed by the applicant of the present application,
The driving force change caused by the engagement of the brake or the clutch when the mode is switched between the first speed change mode and the second speed change mode is reduced by increasing the output torque of the motor / generator.

  According to the mode switching control device of the present invention, the change in driving force at the time of the mode switching is reduced by increasing the output torque of the motor / generator, so that the mode switching shock can be reduced.

  Moreover, since the reduction of the shock is achieved by increasing the torque of the motor / generator, the above-described effects can be achieved at low cost without the difficulty of control as in the case of engine control.

  Further, in the above hybrid transmission, one motor / generator is reduced in torque sharing at the time of mode switching, and it is possible to reliably realize an increase in torque of the motor / generator for mode switching shock reduction, and to achieve the above-described effects. It can be made more reliable.

Hereinafter, embodiments of the present invention will be described in detail based on examples shown in the drawings.
FIG. 1 shows a hybrid transmission having a mode switching control device according to an embodiment of the present invention, which is useful in this embodiment as a transmission for a rear wheel drive vehicle (FR vehicle). The configuration is as follows.

  In the figure, reference numeral 1 denotes a transmission case. Three simple planetary gear sets on the right side (the rear end far from the engine ENG) in the axial direction (left-right direction in the figure) of the transmission case 1, that is, the front side close to the engine ENG. A planetary gear set GF, a central planetary gear set GC, and a rear planetary gear set GR are arranged coaxially and built in, and a composite current two-layer motor 2 can be provided on the left side of the figure (front side close to the engine ENG), for example. The motor / generator set is arranged coaxially with respect to the planetary gear set.

The front planetary gear set GF constitutes the first differential gear G1 in the present invention, the central planetary gear set GC constitutes the third differential gear G3 in the present invention, and the rear planetary gear set GR in the present invention. This constitutes the second differential device G2.
Each of the front planetary gear set GF, the central planetary gear set GC, and the rear planetary gear set GR includes three elements: a sun gear Sf, Sc, Sr, a ring gear Rf, Rc, Rr, and a carrier Cf, Cc, Cr. A differential device having two degrees of freedom is provided.
The carrier Cf and the ring gear Rr are connected to the input shaft 3 coaxially arranged on the input shaft 3 (shown as input In in the collinear diagram described later) to which the rotation of the engine ENG is input via the dry clutch (engine clutch) Cin. The carrier Cr is coupled to the output shaft 4 (shown as output Out in the collinear diagram described later).

The composite current two-layer motor 2 includes an inner rotor 2ri and an annular outer rotor 2ro that surrounds the inner rotor 2ri so as to be coaxially and rotatably supported in the transmission case 1, and between the inner rotor 2ri and the outer rotor 2ro. An annular stator 2s disposed coaxially in the annular space is fixed to the transmission case 1.
The annular stator 2s and the outer rotor 2ro constitute a first motor / generator MG1 that is an outer motor / generator, and the annular stator 2s and the inner rotor 2ri constitute a second motor / generator MG2 that is an inner motor / generator. Configure.
Here, each of the motor / generators MG1 and MG2 functions as a motor that outputs the rotation of each direction and speed (including stop) according to the supplied current when the combined current is supplied as a load on the motor side. When the generator side is applied as a load, it functions as a generator that generates electric power according to rotation by an external force.

First motor / generator MG1 (outer rotor 2ro) is coupled to ring gear Rf, and second motor / generator MG2 (inner rotor 2ri) is coupled to mutually coupled sun gears Sf and Sc.
The ring gear Rc and sun gear Sr coupled to each other, these conjugates to allow binding to the carrier Cc by high clutch Chi, enabling fixing the carrier Cc by low brake B _LO.
Ring gear Rf can be fixed by low and high mode brake B _LH .

When the hybrid transmission configured as described above is represented by a collinear diagram, the low mode used in the low gear ratio region (the first gear mode in the present invention) is similar to FIG. 2, and the high mode used in the high gear ratio region. The mode (second shift mode in the present invention) is as shown in FIG.
As clearly shown in FIG. 2, the rotational order of the elements in the front planetary gear set GF constituting the first differential gear G1 is the ring gear Rf, the carrier Cf, and the sun gear Sf, and constitutes the second differential gear G2. The order of rotation speed of the elements in the rear planetary gear set GR is the ring gear Rr, the carrier Cr, and the sun gear Sr.
The carrier Cf with the middle rotational speed in the front planetary gear set GF and the ring gear Rr with the first rotational speed order in the rear planetary gear set GR are mutually coupled, and the rotational speed in the rear planetary gear set GR The ring gear Rc and the sun gear Sc in the central planetary gear set GC constituting the third differential device G3 are respectively the sun gear Sr with the third order and the sun gear Sf with the third order of the rotational speed in the front planetary gear set GF. Join.

Further, provided the high clutch Chi to couple the carrier Cc and ring gear Rc of planetary gear group GC mutually provided with the low brake B _LO for fixing the carrier Cc of the planetary gear group GC,
The motor / generator MG1 is connected to the ring gear Rf of the front planetary gear set GF, the input In from the engine ENG is connected to the carrier Cf of the front planetary gear set GF, and the wheels are driven to the carrier Cr of the rear planetary gear set GR. The output Out to the system is coupled, and the motor / generator MG2 is coupled to the sun gear Sf of the front planetary gear set GF.

2 and 3, the horizontal axis indicates the distance ratio between the rotating elements determined by the gear ratio of the planetary gear sets GF and GR, that is, the carrier Cf (ring gear Rr) when the distance between the ring gear Rr and the carrier Cr is 1. The ratio of the distance between the ring gear Rf and the ring gear Rf is indicated by α, the ratio of the distance between the carrier Cr and the sun gear Sr (sun gear Sf) is indicated by β,
Further, the ratio of the distance between the carrier Cc and the ring gear Rc when the distance between the sun gear Sc and the carrier Cc is 1 is denoted by δ.

To be described below the shift in the low mode, represented by the diagram of FIG. 2 (first shift mode), in this mode, to secure the carrier Cc by the operation of low brake B _LO.
In the low mode (first shift mode) with the low brake B _LO activated in this way, the lever (shown by the same symbol GC) of FIG. 2 relating to the planetary gear set GC is similar to the illustrated example, and the sun gear. The rotation of the sun gear Sr with respect to Sf and Sc is the reverse rotation determined by the gear ratio between the ring gear Rc and the sun gear Sc.
Therefore, the lever of FIG. 2 related to the planetary gear set GF (indicated by the same symbol GF) and the lever of FIG. 2 related to the planetary gear set GR (indicated by the same symbol GR) are similar to the example shown in FIG. As is apparent from FIG. 2, the rotation speed of the output Out thus made is lower than the rotation speed of the input In. Therefore, the low mode (first transmission mode) is used in the region of the low gear ratio.

  Assuming that the rotation of the input In is constant, the reverse rotation of the sun gear Sr coupled to the ring gear Rc is increased by increasing the reverse rotation of the ring gear Rc by increasing the positive rotation of the sun gear Sf by the motor / generator MG2. As a result, the rotation of the output Out decreases, the gear ratio can be shifted to the low side, and further, the gear ratio can be shifted from the low side infinite (stopped) gear ratio to the reverse gear ratio.

Next, the shift in the high mode (second shift mode) represented by the collinear diagram of FIG. 3 will be described. In this high mode (second shift mode), the planetary gear set GC of the planetary gear set GC is engaged by the engagement of the high clutch Chi. The carrier Cc and the ring gear Rc are coupled.
In this case, since all the rotating elements of the planetary gear set GC are rotated integrally, the sun gear Sr coincides with the sun gears Sf and Sc as shown in the alignment chart of FIG.
At this time, the lever GR (G2) rides on the lever GF (G1), and the gear train composed of the planetary gear sets GF and GR is a straight line of four elements and two degrees of freedom exemplified by the lever GF (G1) in FIG. The motor / generator MG1, the input In from the engine ENG, the output Out to the wheel drive system, and the motor / generator MG2 are arranged in the order of the rotational speeds of the rotating elements.

  Therefore, the lever of FIG. 3 related to the planetary gear set GF (indicated by the same symbol GF) and the lever of FIG. 3 related to the planetary gear set GR (indicated by the same symbol GR) are similar to the illustrated example, and are coupled to the carrier Cr. As is apparent from FIG. 3, the rotation speed of the output Out thus set is lower than the rotation speed of the input In. Therefore, the high mode (second transmission mode) is used in the high gear ratio region.

In the high mode (second shift mode) with the high clutch Chi engaged as described above, when the second motor / generator MG2 is in the reverse (reverse) rotation state, the motor / generator MG2 generates power while generating power. When the first motor / generator MG1 is driven, and when the second motor / generator MG2 is in the forward (forward) rotation state, the first motor / generator MG1 generates power and the second motor / generator MG2 drives the motor. Thus, the vehicle can be driven in a so-called direct power distribution state in which the balance of electricity is balanced.
Furthermore, from this direct power distribution state, by increasing the motor / generator output on the side driven by the motor and reducing the motor / generator generated power on the power generation side, it becomes possible to take out the output exceeding the engine power.
Conversely, from the direct power distribution state, the motor / generator output on the side driven by the motor is reduced, and the motor / generator generated power on the power generation side is increased, so that a chargeable state can be achieved.

FIG. 4 shows the operating characteristics of the above-described hybrid transmission, and FIG. 4 shows the case where the ratios α, β, and δ are α = 1.9, β = 1.8, and δ = 0.42, respectively.
The motor / generator MG1, MG2 rotation speed Nmg1, Nmg2 and torque Tmg1, Tmg2, and the passing power Power when the power balance is balanced in the second shift (high) mode with the high clutch Chi engaged,
Motor / generator MG1, MG2 rotation speeds Nmg1 ', Nmg2' and torques Tmg1 ', Tmg2', and passing electric power in the first shift (low) mode with low brake B _LO engaged '
It is normalized by the rotational speed, torque, and power in the input section, and is shown as a function of the speed ratio of the output rotational speed to the input rotational speed of the transmission (the reciprocal of the speed ratio).

  In the present embodiment, the passing power Power of the motor / generators MG1 and MG2 in the second shift (high) mode and the passing power Power ′ of the motor / generators MG1 and MG2 in the first shift (low) mode are both The first gear (low) mode is selected in the low gear ratio region including the reverse gear ratio, and the second gear (high) is selected in the high gear ratio region. ) Select and use the mode.

In any mode, there are two speed ratios at which the rotation speed of the first motor / generator MG1 or the second motor / generator MG2 is 0. At this point, the vehicle can be driven only by the engine ENG without electrically transmitting power. You can drive.
Also, with the gear ratio between these two points, the transmission power ratio of electrical power transmission, which is less efficient than mechanical transmission, can be reduced with respect to the power transmitted as a transmission. Can be improved.

  Furthermore, the engine output is set to 0 and the motors of the two motor / generators MG1 and MG2 can be driven to drive the vehicle by electric power only (EV). During this time, the dry clutch Cin is disconnected and the engine ENG is turned off. If it is separated from the transmission, it is possible to achieve efficient EV traveling without causing drag of the engine.

In any mode, if the ring gear Rf is fixed by operating the low & high mode brake B _LH , the alignment chart of FIG. 2 and FIG. At this time, driving force assist and energy regeneration can be performed by the motor / generator MG2, and fuel consumption can be reduced.

When the above-described hybrid transmission is switched between the first shift (low) mode and the second shift (high) mode, in the present embodiment, this is performed as follows.
First, switching from the first shift (low) mode to the second shift (high) mode, that is, mode switching at the time of upshift will be described.
As described above, this mode switching is performed by releasing the low brake _BLO from the engaged state and engaging the high clutch Chi from the released state, but the switching is started at a speed ratio on the low side with respect to the synchronization point in FIG. .

Specifically, as shown in FIG. 5, first, in step S1, it is determined whether or not mode switching should be performed by executing a system control program.
In step S2, it is checked whether or not it is determined in step S1 that the upshift mode switching from the first shift (low) mode to the second shift (high) mode should be performed, and the upshift mode switching command is issued. If not, control is returned to step S1 and the system control program here is continued.

  When it is determined in step S2 that there is an upshift mode switching command, in step S3, mode switching related to the rotational speed N2 of the motor / generator MG2 is determined from the mode switching time Δt required for upshift mode switching and the engine torque Te. The end determination rotation speed N2 *, the low brake release start determination rotation speed N2brk, and the high clutch engagement start determination rotation speed N2cl are determined.

Here, as shown in FIG. 8B, N2cl>N2brk> between the mode switching end determination rotation speed N2 *, the low brake release start determination rotation speed N2brk, and the high clutch engagement start determination rotation speed N2cl>. N2 * of to have a relationship, N2cl rather than synchronization point in FIG. 4 in correspondence to the speed ratio of the low side, N2brk is made to correspond to release the start of the low brake B _LO, N2 * is made to correspond to the mode switching completion.
In FIG. 8B, together with FIGS. 8A, 8C, and 8D, the time when the rotational speed N2 of the motor / generator MG2 is reduced to the high clutch engagement start determination rotational speed N2cl is t1, The time when the low brake release start determination rotational speed N2brk is decreased is indicated by t2, and the time when the mode switch end determination rotational speed N2 * is further decreased is indicated by t3.

In the next step S4 in FIG. 5, it is determined whether or not the rotation speed N2 of the motor / generator MG2 has decreased to the mode switching end determination rotation speed N2 *, that is, whether or not the moment t3 in FIG. 8 has been reached.
If not yet, that is, if the mode is being switched, the control proceeds to step S5, where the rotational speed N2 of the motor / generator MG2 is less than the high clutch engagement start rotational speed N2cl and the low brake release start is started. It is determined whether or not it is less than the determined rotational speed N2brk, that is, whether it is the instant t2-t3 period or the instant t1-t2 period in FIG.

When it is determined in step S5 that the period is from the instant t1 to t2, in step S6, the engagement of the high clutch Chi and the assist by the motor / generators MG1 and MG2 are performed by the first-term mode switching control.
This first-term mode switching control is as shown in FIG. 6. First, in step S11, a deviation ΔN2 (= N2 * −N2) between the rotational speed N2 of the motor / generator MG2 and the rotational speed N2 * of the mode switching end determination. Is calculated.
In the next step S12, the target high clutch hydraulic pressure Pcl * is determined from the motor / generator rotation deviation ΔN2, the engine torque Te, and the mode switching time Δt based on the target hydraulic pressure map mapPcl related to the high clutch hydraulic pressure Pcl. Obtained as shown in (a).

In step S13, from the target high clutch hydraulic pressure Pcl *, the motor / generator MG1, MG1, MG1, MG1, MG1, MG1, MG2, MG1, MG2 corresponding to the target high clutch hydraulic pressure Pcl * based on the maps mapF1cl, mapF2cl related to the assist torque for preventing the mode switching shock of the motor / generator MG1, MG2. MG2 mode switching shock prevention assist torque T1assist and T2assist are determined respectively.
In step S14, the mode switching shock prevention motor / generator assist torques T1assist, T2assist according to the target high clutch hydraulic pressure Pcl * are multiplied by the coefficients k1 (Te), k2 (Te) according to the engine torque Te. Target assist torque T1assist * = k1 (Te) × T1assist, T2assist * = k2 (Te) × T2assist for motor / generator MG1, MG2 is obtained as shown at instants t1 to t2 in FIG.

In step S5 of FIG. 5, when it is determined that the instant t2 to t3 period has entered after the lapse of the instant t1 to t2 period shown in FIG. 8, in step S7, the continuous engagement of the high clutch Chi and the late mode switching control are performed. The motor / generators MG1 and MG2 are continuously assisted and the low brake _BLO is released.
This late mode switching control is as shown in FIG. 7. First, in step S21, a deviation ΔN2 (= N2 * −N2) between the rotational speed N2 of the motor / generator MG2 and the rotational speed N2 * of the mode switching end determination. Is calculated.

In the next step S22, the target high clutch hydraulic pressure Pcl * is determined from the motor / generator rotation deviation ΔN2, the engine torque Te, and the mode switching time Δt based on the target hydraulic pressure map mapPcl related to the high clutch hydraulic pressure Pcl. Continue to seek as shown in (a),
Similarly, the target low brake oil pressure Pbrk * is shown in FIG. 8A based on the target oil pressure map mapPbrk related to the low brake oil pressure Pbrk from the motor / generator rotation deviation ΔN2, the engine torque Te, and the mode switching time Δt. Ask.

In step S23, from the target high clutch hydraulic pressure Pcl * and the target low brake hydraulic pressure Pbrk *, the target high clutch hydraulic pressure Pcl * and the mapF1cl and mapF2cl regarding the assist torque for preventing the mode switching shock of the motor / generators MG1 and MG2 are determined. Assist torques T1assist and T2assist for mode switching shock prevention of motor / generators MG1 and MG2 corresponding to the target low brake hydraulic pressure Pbrk * are determined.
In step S24, the mode switching shock prevention motor / generator assist torques T1assist, T2assist according to the target high clutch hydraulic pressure Pcl * and the target low brake hydraulic pressure Pbrk *, and coefficients k1 (Te), k2 ( The target assist torque T1assist * = k1 (Te) × T1assist, T2assist * = k2 (Te) × T2assist for motor / generator MG1, MG2 shock prevention by multiplication with Te) is instant t2 in FIG. As in ~ t3.

  When the above-described process in step S6 shown in FIG. 5 is completed and then the above-described process in step S7 is completed, it is recognized that step S4 has reached the instant t3 in FIG. 8 by the determination of N2 <N2 *. The control proceeds to step S8, where the mode switching is terminated.

The above-described upshift mode switching control is supplemented by FIG. 8. When an upshift mode switching command is issued, the motor / generator MG2 rotation speed N2 decreases to the instant t1 when the high clutch engagement start determination rotation speed N2cl is reduced, that is, The target high clutch hydraulic pressure Pcl * rises at a speed ratio on the low side of the synchronization point in FIG. 4 and the engagement of the high clutch Chi starts.
When the engagement of the high clutch Chi is started, the rotational speeds of the sun gear Sf (Sc) and the sun gear Sr approach each other as indicated by arrows a1 and a2 from the low mode state of FIG. 9, and as a result, the sun gear Sf (Sc ) Is reduced as indicated by a3.

At this time, torque is generated to raise the rotational speed of motor / generator MG1 having a large inertia as shown by an arrow a4 and to move toward the lever state shown by a one-dot chain line, and the engine ENG is also lowered as shown by an arrow a5. Therefore, torque is generated in a direction that reduces the rotational speed of the output shaft Out.
For this reason, as apparent from the time series change of the output torque To during the instants t1 to t3 (during the mode switching period Δt) in FIG.

  By the way, in this embodiment, when the engagement of the high clutch is started at the instant t1, the assist torque T1assist * and T2assist * corresponding to the target high clutch hydraulic pressure Pcl * and the engine torque Te are supplied to the motor / generator until the instant t2. MG1 and MG2 are commanded, and during the instant t2 to t3, the target high clutch hydraulic pressure Pcl * and target low brake hydraulic pressure Pbrk * and assist torques T1assist * and T2assist * corresponding to the engine torque Te are given to the motor / generator MG1 and MG2. Since the command is issued, as shown in FIG. 8D, the output torque To can be raised to reduce the pull-in change of the driving force as shown by hatching.

Here, as shown in FIG. 8C, the assist torque T1assist * of the motor / generator MG1 is an assist torque in the direction of increasing torque in order to reduce the pull-in of the torque due to the inertia of the motor / generator MG1,
Further, as shown in FIG. 8 (c), the assist torque T2assist of the motor / generator MG2 decreases the motor / generator torque in order to balance the lever of the collinear chart with the high clutch engagement force and the torque of the motor / generator MG2. Direction assist torque.

As is clear from FIG. 4, since the torque sharing Tmg1, Tmg1 'of the motor / generator MG1 near the synchronization point is close to 0 and smaller than the torque sharing Tmg2, Tmg2' of the motor / generator MG2, the motor / generator MG1 can easily generate assist torque T1assist *.
On the other hand, since the motor / generator MG2 having a large torque share is reduced in torque by the assist torque T2assist *, this can also be realized easily, and fluctuations in driving force can be suppressed and mode switching can be facilitated.

The progressive engagement of the high clutch, the rotational speed N2 of the motor / generator MG2 reaches time t2 in FIG. 8 drops to a low brake release determination rotational speed N2brk, reduced low brake B _LO is the target low brake hydraulic Pbrk * The release is started by this, but from this time, the rate of decrease in the rotational speed N2 of the motor / generator MG2 decreases.
Here, the assist torque T2assist * of the motor / generator MG2 is the torque of the motor / generator MG2 so that the lever of the collinear diagram is balanced by the low brake engagement force, the high clutch engagement force, and the motor / generator MG2 torque. Occurs in the direction of decreasing.
Thereafter, by continuing the engagement of the high clutch and releasing the low brake, the rotation speed N2 of the motor / generator MG2 is reduced to the mode switching end determination rotation speed N2 * until the instant t3 in FIG. 8, where the mode switching is performed. finish.

By the way, in the upshift mode switching of the present embodiment, the torque assist by the motor / generators MG1 and MG2 as described above is performed between t1 and t3 of the output torque To shown by the solid line in FIG. 8D (during the mode switching time Δt). ) Can be eliminated as shown by hatching to reduce the mode switching shock,
Since the mode switching control including the torque assist by the motor / generators MG1 and MG2 is started on the low side from the synchronization point, the speed ratio (speed ratio) is continuously changed, and the mode switching is less uncomfortable.

In the upshift mode switching of this embodiment, while monitoring the rotational speed N2 of the motor / generator MG2, the high clutch is engaged when the monitored rotational speed N2 becomes the mode switching start rotational speed (first rotational speed) N2cl. After that, when the monitor rotation speed N2 becomes the low brake release determination rotation speed (second rotation speed) N2brk, the low brake release is started and the low mode (first shift mode) is changed to the high mode (second shift mode). (Upshift mode) to the shift mode)
The mode switching start determination rotation speed (first rotation speed) N2cl and the low brake release determination rotation speed (second rotation speed) N2brk are determined according to the mode switching time Δt required for the mode switching and the engine torque Te, respectively. Because
Mode switching with little change in driving force can be realized with certainty.

In addition, the engaging force (target hydraulic pressure Pcl *, Pbrk *) of the high clutch and the low brake is determined based on the rotational speed N2 of the motor / generator MG2 and the engine torque Te, and the engaging force of the clutch and the brake (target) In order to determine the output torque increase amount of the motor / generator according to the hydraulic pressure Pcl *, Pbrk *)
The assist force of the motor / generator MG1, MG2 can be set by the engagement reaction force of the high clutch and the low brake, and the torque of the motor / generator MG2 can be continuously switched.

Next, conversely to the above description, mode switching from the second speed change (high) mode to the first speed change (low) mode, that is, during downshift will be described.
As described above, this downshift mode switching is performed by releasing the high clutch Chi from the engaged state and engaging the low brake _BLO from the released state, but the switching is performed at a speed ratio higher than the synchronization point in FIG. Let it begin.

Specifically, as shown in FIG. 10, first, in step S31, it is determined whether or not mode switching should be performed by executing a system control program.
In step S32, it is checked whether or not it is determined in step S1 that the downshift mode switching from the second shift (high) mode to the first shift (low) mode should be performed, and the downshift mode switching command is issued. If not, control returns to step S31 and the system control program here is continued.

  When it is determined in step S32 that there is a downshift mode switching command, in step S33, the mode switching time Δt required for the downshift mode switching (denoted by the same sign as the upshift mode switching time for convenience), and the engine From the torque Te, the mode change end determination speed N2 * (represented by the same sign as the mode change end determination speed at the time of the upshift mode switching) and the low brake engagement regarding the rotation speed N2 of the motor / generator MG2. Start determination rotation speed N2brk (for the sake of convenience, indicated by the same sign as the low brake release start determination rotation speed N2brk at the time of upshift mode switching) and high clutch release start determination rotation speed N2cl (for the sake of convenience, at the time of the upshift mode switching) With the same sign as the high clutch engagement start speed To determine the) and.

Here, as shown in FIG. 13B, N2brk>N2cl> between the mode switching end determination rotation speed N2 *, the low brake engagement start determination rotation speed N2brk, and the high clutch release start determination rotation speed N2cl. With N2 * relationship, N2brk corresponds to the speed ratio higher than the synchronization point in FIG. 4, N2cl corresponds to the start of releasing the high clutch Chi, and N2 * corresponds to the end of mode switching.
In FIG. 13 (b), together with FIGS. 13 (a), (c) and (d), the time when the rotational speed N2 of the motor / generator MG2 decreases to the low brake engagement start determination rotational speed N2brk is t1, The time when the high clutch release start determination rotational speed N2cl is decreased is indicated by t2, and the time when it is further decreased by the mode switching end determination rotational speed N2 * is indicated by t3.

In the next step S34 in FIG. 10, it is determined whether or not the rotation speed N2 of the motor / generator MG2 has decreased to the mode switching end determination rotation speed N2 *, that is, whether or not the moment t3 in FIG. 13 has been reached.
If not yet, that is, if the mode is being switched, the control proceeds to step S35, where the rotational speed N2 of the motor / generator MG2 is less than the high clutch disengagement start determination rotational speed N2cl and the low brake engagement start is started. It is determined whether or not it is less than the determined rotational speed N2brk, that is, whether it is the instant t2 to t3 period or the instant t1 to t2 period in FIG.

When it is determined in step S35 that the period is the instant t1 to t2, in step S36, the low brake _BLO is engaged and the motor / generators MG1 and MG2 are assisted by the first-term mode switching control.
This first-term mode switching control is as shown in FIG. 11. First, in step S41, the deviation ΔN2 (= N2 * −N2) between the rotational speed N2 of the motor / generator MG2 and the rotational speed N2 * for determining the mode switching end. Is calculated.
In the next step S42, the target low brake oil pressure Pbrk * is calculated based on the target oil pressure map mapPbrk1 related to the low brake oil pressure Pbrk based on the motor / generator rotation deviation ΔN2, the engine torque Te, and the mode switching time Δt. Obtained as shown in (a).

In step S43, the motor / generator MG1, corresponding to the target low brake hydraulic pressure Pbrk * is calculated from the target low brake hydraulic pressure Pbrk * based on the maps mapF1brk, mapF2brk regarding the assist torque for preventing the mode switching shock of the motor / generator MG1, MG2. MG2 mode switching shock prevention assist torques T1assist and T2assist (denoted by the same symbol as the mode switching shock prevention assist torque at the time of upshift mode switching) are respectively determined.
In step S44, the mode switching shock prevention motor / generator assist torques T1assist, T2assist according to the target low brake hydraulic pressure Pbrk * are multiplied by the coefficients k1 (Te), k2 (Te) according to the engine torque Te. Target assist torque T1assist * = k1 (Te) × T1assist, T2assist * = k2 (Te) × T2assist for motor / generator MG1 and MG2 is obtained as shown at instants t1 to t2 in FIG.
For convenience, the mode switching shock prevention target assist torques T1assist * and T2assist * are also denoted by the same reference numerals as the mode switching shock prevention assist torque at the time of the upshift mode switching.

In step S35 of FIG. 10, when it is determined that the instant t2 to t3 period has entered after the lapse of the instant t1 to t2 period shown in FIG. 13, in step S37, the low brake _BLO is continuously _engaged by the late mode switching control. The motor / generators MG1 and MG2 are continuously assisted, and the high clutch Chi is released.
This late mode switching control is as shown in FIG. 12. First, in step S51, the deviation ΔN2 (= N2 * −N2) between the rotational speed N2 of the motor / generator MG2 and the rotational speed N2 * for determining the mode switching end. Is calculated.

In the next step S52, the target low brake hydraulic pressure Pbrk * is calculated from the motor / generator rotation deviation ΔN2, the engine torque Te, and the mode switching time Δt based on the target hydraulic pressure map mapPbrk2 relating to the low brake hydraulic pressure Pbrk. Continue to seek as shown in (a),
Similarly, from the motor / generator rotation deviation ΔN2, engine torque Te, and mode switching time Δt, the target high clutch oil pressure Pcl * is shown in FIG. 13A based on the target oil pressure map mapPcl2 related to the high clutch oil pressure Pcl. Ask.

In step S53, from the target high clutch hydraulic pressure Pcl * and the target low brake hydraulic pressure Pbrk *, the target high clutch hydraulic pressure Pcl * and the target high clutch hydraulic pressure Pcl * and the mapF1, mapF2 relating to the assist torque for preventing the mode switching shock of the motor / generators MG1, MG2. Assist torques T1assist and T2assist for mode switching shock prevention of motor / generators MG1 and MG2 corresponding to the target low brake hydraulic pressure Pbrk * are determined.
In step S54, motor / generator assist torque T1assist, T2assist for mode switching shock prevention corresponding to the target high clutch hydraulic pressure Pcl * and target low brake hydraulic pressure Pbrk *, and coefficients k1 (Te), k2 ( The target assist torque T1assist * = k1 (Te) × T1assist, T2assist * = k2 (Te) × T2assist for motor / generator MG1 and MG2 is prevented by multiplication with Te) at the instant t2 in FIG. As in ~ t3.

  When the above-described processing in step S36 shown in FIG. 10 is finished and then the above-described processing in step S37 is finished, step S34 recognizes that the moment t3 in FIG. 13 has been reached by the determination of N2 <N2 *. The control proceeds to step S8, where the mode switching is terminated.

To add the downshift mode switching control described above with reference to FIG. 13, when the downshift mode switching command is issued, at the instant t1 when the rotational speed N2 of the motor / generator MG2 is reduced to the low brake engagement start determination rotational speed N2brk, that is, rising the target low brake hydraulic Pbrk * at the high side speed ratio than the synchronization point in FIG. 4, the engagement of low brake B _LO begins.
When the engagement of the low brake _BLO is started, the rotational speeds of the sun gear Sf (Sc) and the sun gear Sr decrease from the high mode state shown in FIG. 14 as indicated by an arrow b1, and as a result, are coupled to the sun gear Sf (Sc). The number of rotations of the motor / generator MG2 is reduced.

At this time, torque is generated to raise the rotational speed of motor / generator MG1 having a large inertia upward as indicated by arrow b2 and to move toward the lever state indicated by the alternate long and short dash line, and the engine rotational speed is decreased as indicated by arrow b3. Therefore, a torque in the decreasing direction is generated on the output shaft Out.
For this reason, as apparent from the time-series change of the output torque To during the instants t1 to t3 (during the mode switching period Δt) in FIG.

  By the way, in this embodiment, when the low brake engagement is started at the instant t1, the assist torques T1assist * and T2assist * corresponding to the target low brake hydraulic pressure Pbrk * and the engine torque Te are supplied to the motor / generator until the instant t2. MG1 and MG2 are commanded, and between the instants t2 and t3, the target low brake hydraulic pressure Pbrk *, the target high clutch hydraulic pressure Pcl * and the assist torques T1assist * and T2assist * corresponding to the engine torque Te are given to the motor / generator MG1 and MG2. Since the command is issued, it is possible to raise the output torque To and reduce the pull-in change of the driving force as shown by hatching in FIG.

Here, as shown in FIG. 13C, the assist torque T1assist * of the motor / generator MG1 is an assist torque in the direction of increasing torque in order to reduce the torque pull-in due to the inertia of the motor / generator MG1.
Further, as shown in FIG. 13C, the assist torque T2assist of the motor / generator MG2 decreases the motor / generator torque in order to balance the lever of the collinear chart with the high clutch engagement force and the torque of the motor / generator MG2. Direction assist torque.

As is clear from FIG. 4, since the torque sharing Tmg1, Tmg1 'of the motor / generator MG1 near the synchronization point is close to 0 and smaller than the torque sharing Tmg2, Tmg2' of the motor / generator MG2, the motor / generator MG1 can easily generate assist torque T1assist *.
On the other hand, since the motor / generator MG2 having a large torque share is reduced in torque by the assist torque T2assist *, this can also be realized easily, and fluctuations in driving force can be suppressed and mode switching can be facilitated.

When the low brake is engaged, the motor / generator MG2 rotational speed N2 decreases to the high clutch disengagement determination rotational speed N2cl and reaches the instant t2 in FIG. 13, and the high clutch Chi decreases due to a decrease in the target high clutch hydraulic pressure Pcl *. Release starts, but at this time, the rate of decrease in the rotational speed N2 of the motor / generator MG2 decreases.
Here, the assist torque T2assist * of the motor / generator MG2 is the torque of the motor / generator MG2 so that the lever of the collinear diagram is balanced by the low brake engagement force, the high clutch engagement force, and the motor / generator MG2 torque. Occurs in the direction of decreasing.
After that, by continuing the engagement of the low brake and the release of the high clutch, the motor / generator MG2 reaches the instant t3 in FIG. 13 when the rotational speed N2 of the motor / generator MG2 decreases to the mode switching end rotational speed N2 *. finish.

By the way, at the time of the downshift mode switching, similarly to the above-described upshift mode switching, the torque assist by the motor / generators MG1 and MG2 as described above is performed, so that t1 of the output torque To shown by the solid line in FIG. The mode switching shock can be reduced by eliminating the drop in the period between t3 (during the mode switching time Δt) as indicated by hatching,
Since the mode switching control including the torque assist by the motor / generators MG1 and MG2 is started at a higher side than the synchronization point, the speed ratio (speed ratio) is continuously changed, so that the mode switching is less uncomfortable.

At this time, while monitoring the rotational speed N2 of the motor / generator MG2, when the monitored rotational speed N2 becomes the mode switching start determination rotational speed (first rotational speed) N2brk, the low brake engagement is started, and then the monitor When the rotation speed N2 becomes the high clutch release determination rotation speed (second rotation speed) N2cl, the high clutch release is started and the downshift from the high mode (second shift mode) to the low mode (first shift mode) is started. Configure to control the progress of mode switching,
The mode switching start determination rotation speed (first rotation speed) N2brk and the high clutch release determination rotation speed (second rotation speed) N2cl are determined according to the mode switching time Δt required for the mode switching and the engine torque Te, respectively. Because
Mode switching with little change in driving force can be realized with certainty.

In addition, the engaging force of the low brake and the high clutch (target hydraulic pressures Pbrk * and Pcl *) is determined based on the rotational speed N2 of the motor / generator MG2 and the engine torque Te, and the engaging force of the brake and clutch (target) In order to determine the output torque increase amount of the motor / generator according to the hydraulic pressure (Pbrk *, Pcl *)
The assist force of the motor / generator MG1, MG2 can be set by the engagement reaction force of the low brake and the high clutch, and the torque of the motor / generator MG2 can be continuously switched.

  Note that the mode switching control device according to the present invention is not limited to the hybrid transmission as shown in FIG. 1, but has two types of continuously variable transmission ratio modes and performs mode switching between both modes. It can be applied to all hybrid transmissions.

It is a vertical side view of the hybrid transmission provided with the mode switching control apparatus which becomes one Example of this invention. FIG. 3 is an alignment chart in a low mode of the hybrid transmission shown in FIG. 2. It is a collinear diagram in the high mode of the hybrid transmission. FIG. 5 is an operation characteristic diagram showing the relationship between the speed ratio of the hybrid transmission, the rotational speed and torque of both motors / generators, and the passing power for each selected mode. It is a flowchart which shows the control program at the time of mode switching from the low mode to the high mode of the hybrid transmission. It is a flowchart which shows the program regarding the first period mode switching control of the upshift mode switching. It is a flowchart which shows the program regarding the latter period mode switching control of the upshift mode switching. FIG. 6 is an operation time chart of the upshift mode switching control, wherein (a) is a time chart showing a time-series change in target hydraulic pressure, (b) is a time chart showing a time-series change in motor / generator rotation speed, and (c). (A) is a time chart which shows the time series change regarding the assist torque of a motor / generator, (d) is a time chart which shows the time series change of output torque. FIG. 3 is a collinear diagram related to the hybrid transmission of FIG. 2 during the upshift mode switching control. 3 is a flowchart showing a control program when the hybrid transmission of FIG. 2 is switched from a high mode to a low mode. It is a flowchart which shows the program regarding the first period mode switching control of the downshift mode switching. It is a flowchart which shows the program regarding the latter period mode switching control of the downshift mode switching. FIG. 5 is an operation time chart of the downshift mode switching control, wherein (a) is a time chart showing a time series change of a target hydraulic pressure, (b) is a time chart showing a time series change of a motor / generator rotation speed, and (c). (A) is a time chart which shows the time series change regarding the assist torque of a motor / generator, (d) is a time chart which shows the time series change of output torque. FIG. 3 is a collinear diagram related to the hybrid transmission of FIG. 2 during the downshift mode switching control.

Explanation of symbols

1 Transmission case
ENG engine (motor)
2 Composite current 2-layer motor
MG1 1st motor / generator
MG2 2nd motor / generator 3 Input shaft 4 Output shaft
G1 first differential
G2 Second differential
G3 Third differential
GF Front planetary gear set
GC middle planetary gear set
GR Rear planetary gear set
Sf, Sc, Sr Sun gear
Rf, Rc, Rr Ring gear
Cf, Cc, Cr carrier
Cin dry clutch
Chi high clutch
B _LO low brake
B _LH Low & High mode brake

Claims (8)

Comprising first, second, and third differentials that determine the rotational state of the two elements and determine the rotational state of the other elements;
One element of the first and second differential devices is coupled to each other, and one element of the first and second differential devices excluding these elements is connected to each other by a third differential device;
The engine, the output shaft, and the two motor / generators are coupled to the components of the first and second differential units including the above elements, and the engine, the output shaft, and the two motor / generators are correlated. ,
Direction in which the rotational speeds of the elements of the first and second differential units connected to each other by the third differential unit approach or move away from each other, obtained by fastening a brake that fixes one element of the third differential unit The first and second differential gears connected to each other by the third differential gear, which are obtained by engaging the first shift mode that can be changed to and the clutch that mutually couples the two elements of the third differential gear. In the hybrid transmission having two types of continuously variable transmission ratio modes with the second transmission mode in which the above-mentioned elements can rotate integrally,
A mode switching control device for a hybrid transmission configured to reduce a driving force change caused by engagement of the brake or clutch when the mode is switched between the transmission modes by increasing an output torque of the motor / generator. . In the mode switching control device according to claim 1,
The mode switching control of the hybrid transmission, wherein the motor / generator for increasing the output torque is a motor / generator having a lower torque sharing at the time of the mode switching among the two motors / generators. apparatus. 3. The mode switching control device according to claim 1, wherein the first shift mode is responsible for a shift on the low side, and the second shift mode is responsible for a shift on the high side.
When switching from the first speed change mode to the second speed change mode, the mode change is configured to start on the low side of the synchronization point where the motor / generator passing power in both speed change modes is the same. A mode change control device for a hybrid transmission. In the mode switching control device according to claim 3,
While monitoring the rotation speed of the motor / generator related to the elements of the first and second differential gears connected to each other by the third differential gear, when the monitor rotation speed becomes the first rotation speed, The engagement is started, and then the release of the brake is started when the monitor rotation speed becomes the second rotation speed, and the mode switching from the first shift mode to the second shift mode is controlled to progress,
The hybrid transmission characterized in that the first rotation speed and the second rotation speed are determined in accordance with a mode switching time required for mode switching from the first shift mode to the second shift mode and an engine torque, respectively. Mode switching control device. In the mode switching control device according to claim 4,
Determining the fastening force of the clutch and the brake based on the rotational speed of the motor / generator and the engine torque related to the elements of the first and second differentials mutually connected by the third differential; A mode change control device for a hybrid transmission, wherein an increase amount of output torque of the motor / generator is determined in accordance with an engagement force of the clutch and brake. 3. The mode switching control device according to claim 1, wherein the first shift mode is responsible for a shift on the low side, and the second shift mode is responsible for a shift on the high side.
When switching from the second speed change mode to the first speed change mode, the mode change is configured to start at a higher side than the synchronization point at which the motor / generator passing power is the same in both speed change modes. A mode change control device for a hybrid transmission. In the mode switching control device according to claim 6,
While monitoring the rotation speed of the motor / generator related to the elements of the first and second differential gears connected to each other by the third differential gear, when the monitor rotation speed becomes the first rotation speed, The engagement is started, and then the release of the clutch is started when the monitor rotational speed reaches the second rotational speed, and the mode switching from the second speed change mode to the first speed change mode is controlled to progress.
The hybrid transmission characterized in that the first rotation speed and the second rotation speed are determined in accordance with a mode switching time required for mode switching from the second shift mode to the first shift mode and an engine torque, respectively. Mode switching control device. In the mode switching control device according to claim 7,
Determining the fastening force of the brake and the clutch based on the rotational speed of the motor / generator and the engine torque related to the elements of the first and second differentials mutually connected by the third differential; A mode change control device for a hybrid transmission, wherein an increase amount of output torque of the motor / generator is determined in accordance with an engaging force of the brake and clutch.

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