JP6447606B2 - Vehicle drive device - Google Patents

Description

  The present invention includes an engine, an automatic transmission that transmits the output rotation of the engine to the wheel side while shifting, a power connection / disconnection clutch that connects and disconnects the output shaft of the engine and the input shaft of the automatic transmission, The present invention relates to a vehicle drive device including a regenerative device linked to an input shaft of an automatic transmission.

  The following Patent Document 1 is known as an example of a vehicle to which the drive device as described above is applied. Specifically, the vehicle drive device disclosed in Patent Document 1 rotationally drives an engine, an automatic transmission, a clutch that connects and disconnects an output shaft of the engine and an input shaft of the automatic transmission, and an input shaft of the automatic transmission. And an electric motor. The motor can also function as a generator that generates power by obtaining driving force from the input shaft of the automatic transmission.

  In the vehicle of Patent Document 1, at the time of a downshift to change the gear stage of the automatic transmission from a high gear stage to a low gear stage, the clutch is released and the motor functions as a generator to generate regenerative power generation. Further, the amount of power generated by the regenerative power generation (regenerative torque) is obtained by a predetermined calculation using as a parameter the hydraulic pressure supplied to the friction engagement elements (first and second friction engagement elements) whose engagement state changes during downshift. It is determined. As a result, it is said that the regenerative power generation amount at the time of downshift can be ensured to the maximum, and the fuel efficiency can be improved.

Japanese Patent Laid-Open No. 2006-132432

  Here, in Patent Document 1, during the downshift operation, the fastening force of the first frictional engagement element is gradually decreased through a plurality of stages, and the second frictional engagement element is subjected to a plurality of stages. It is gradually increased. The reason why the engagement patterns of the frictional engagement elements are switched over over a relatively long time in this manner is to sufficiently secure the regenerative power generation amount during the downshift while suppressing a sudden change (shift shock) of the vehicle acceleration. It is thought that.

  However, when the frictional engagement element is controlled in the manner as described above, the time required to complete the switching of the engagement pattern after the request for the downshift is completed (the time required for the downshift) becomes longer. There is a problem. In addition, since each frictional engagement element slips for a relatively long time, there is a problem that energy loss (slip loss) due to frictional heat or the like caused by the slip increases.

  The present invention has been made in view of the above circumstances, and provides a vehicle drive device capable of realizing a rapid downshift of an automatic transmission while maintaining good energy efficiency. With the goal.

In order to solve the above-described problems, the present invention provides an engine having an output shaft, an input shaft connected to the output shaft of the engine so as to be connectable to and disconnected from the wheel while shifting the rotation of the input shaft. Power that can be switched between an automatic transmission that transmits to the side, a fastening state in which the output shaft of the engine and an input shaft of the automatic transmission rotate together, and a release state in which the connection is released A connection / disconnection clutch, a regenerative mode that is linked to the input shaft of the automatic transmission, converts the rotational force of the input shaft into energy and stores it, and a drive mode that drives the input shaft using the stored energy. A regenerative device capable of switching, a first shift control unit for releasing the power connection / disconnection clutch at the time of downshift to switch the gear of the automatic transmission from a high gear to a low gear, and the power connection / disconnection clutch The release after the switch, the engine control unit to increase toward the synchronous rotational speed corresponding to the rotational speed of the output shaft to the speed reduction ratio after the downshift of the engine, during the release period of the power disengaging clutch, the regeneration device A regenerative control unit that applies a positive torque to the input shaft of the automatic transmission, and the rotational speed of the output shaft of the engine rises to the synchronous rotational speed. And a second shift control unit that engages the power connection / disconnection clutch and switches the friction engagement element to the engagement pattern that achieves the low gear stage. Item 1).

  According to the present invention, the power connection / disconnection clutch is first released at the time of downshift, and the output shaft of the engine is raised toward the synchronous rotation speed in that state, so that it becomes free as the power connection / disconnection clutch is released. The rotation speed of the output shaft of the engine can be increased to the synchronous rotation speed quickly and accurately. Moreover, since the mode of the regenerative device is changed to the drive mode along with the release of the power disconnection clutch, the acceleration of the vehicle is driven by applying positive torque from the regenerative device to the input shaft of the automatic transmission separated from the engine. It is possible to maintain the same acceleration as before the clutch is released. Further, since the power connection / disconnection clutch is engaged after the engine output shaft rotation speed has increased to the synchronous rotation speed, the fully-accelerated engine output shaft rotation is automatically transmitted via the power connection / disconnection clutch. , The rotational speed of the input shaft increases in a short time to the same rotational speed as the output shaft of the engine. For this reason, the operation of switching the engagement pattern of the frictional engagement element of the automatic transmission for changing the gear stage can be performed at a relatively high speed in accordance with the rotational increase speed of the input shaft, and the switching can be completed quickly. Thus, a low gear after downshifting can be achieved. Moreover, such rapid switching of the fastening pattern means that the slip loss of the friction fastening elements, that is, the energy loss due to the frictional heat caused by the relative rotation of the friction plates is reduced. Therefore, according to the present invention, it is possible to shorten the time required for the downshift and to reduce the slip loss and improve the energy efficiency.

  Preferably, the regeneration control unit maintains the mode of the regeneration device in the drive mode until switching of the engagement pattern of the frictional engagement element is completed (Claim 2).

  According to this configuration, since the positive torque is continuously applied from the regenerative device to the input shaft of the automatic transmission until the switching of the fastening pattern is completed, the rotation speed of the input shaft of the automatic transmission is the same as the output shaft of the engine. The time required to rise to the number can be further shortened. As a result, it is possible to further accelerate the downshift and reduce slip loss.

  In the above configuration, more preferably, the regenerative control unit switches the mode of the regenerative device from the drive mode to the regenerative mode when the switching of the engagement pattern of the frictional engagement element is completed, and inputs the automatic transmission. A reverse torque is applied to the shaft (claim 3).

  According to this configuration, reverse torque (brake) is applied to the input shaft of the automatic transmission from the regenerative device that has been switched to the regenerative mode upon completion of the switching of the engagement pattern. Accordingly, it is possible to effectively suppress the occurrence of a shift shock in which the vehicle acceleration suddenly changes. In addition, since the shift shock is suppressed by using the regenerative device, the rotational force of the input shaft can be converted into energy and stored every time the downshift is performed, and the stored energy can be taken out as work at another opportunity. .

In the above configuration, more preferably, the regenerative control unit gradually increases the reverse torque applied to the input shaft from the regenerative device switched to the regenerative mode after the engagement pattern switching of the frictional engagement element is completed. The regenerative device is controlled so as to approach zero (claim 4).

Thus, when such Ru gradually reduce the reverse torque applied to the input shaft after completion of switching of the fastening pattern (close to zero), if, as reduced to zero inverse torque suddenly example Unlike the case, since the sudden change in the rotational speed of the input shaft can be avoided, it is possible to prevent the behavior of the vehicle from becoming unstable due to the sudden change in the rotational speed.

  Preferably, the regenerative device includes a hydraulic pump motor linked to the input shaft, and a pressure accumulator in which oil supplied to and discharged from the hydraulic pump motor is stored, and the hydraulic pump motor is connected to the input shaft. It is possible to switch between a regenerative mode that operates as a pump that is driven by the pressure pump and supplies oil to the pressure accumulator, and a drive mode that operates as a motor that drives the input shaft upon receiving oil supply from the pressure accumulator. Item 5).

  According to this configuration, the rotational force of the input shaft can be converted into hydraulic energy and stored in the accumulator, and the input shaft can be driven using the hydraulic energy stored in the accumulator.

  As described above, according to the vehicle drive device of the present invention, it is possible to realize a rapid downshift of the automatic transmission while maintaining good energy efficiency.

1 is a plan view schematically showing an overall configuration of a vehicle to which a drive device according to an embodiment of the present invention is applied. It is a circuit diagram which shows the circuit structure of a hydraulic pump motor. It is a figure for demonstrating the operating state of a hydraulic pump motor, (a) is the oil flow at the time of the regeneration mode which operate | moves as a pump, (b) is the oil flow at the time of the drive mode which operate | moves as a motor. Each is shown. It is a block diagram which shows the control system of the said drive device. It is a flowchart for demonstrating the control action at the time of the downshift gear shift which makes the gear stage of an automatic transmission low. It is a time chart for demonstrating the control action at the time of the said downshift.

(1) Overall Configuration of Vehicle FIG. 1 is a plan view schematically showing an overall configuration of a vehicle to which a drive device according to an embodiment of the present invention is applied. The vehicle shown in this figure includes an engine 1 composed of a spark ignition gasoline engine provided as a driving power source, and a power interruption provided along a power transmission path for transmitting output rotation of the engine 1 to wheels 7. A contact clutch 2, a regenerative device 3, an automatic transmission 4, a differential device 5, and a drive shaft 6 are provided. Although details will be described later, the regenerative device 3 can generate hydraulic pressure from the rotation input to the automatic transmission 4 and drive the wheels 7 via the automatic transmission 4 by the generated hydraulic pressure. As described above, the vehicle according to the present embodiment includes an additional power source different from the engine 1 and can be said to be a kind of so-called hybrid vehicle. However, since hydraulic pressure is used instead of electricity, it is sometimes called a hydraulic hybrid vehicle.

  The engine 1 includes an engine main body 11 that internally burns supplied fuel (gasoline), and an output shaft 12 that rotates by receiving combustion energy generated in the engine main body 11.

  The automatic transmission 4 includes a stepped transmission mechanism 15 that can achieve a plurality of gear stages having different reduction ratios, and an input shaft 16 that is coaxially connected to the output shaft 12 of the engine 1 via the power connection / disconnection clutch 2. And an output shaft 17 that connects the output gear of the speed change mechanism 15 and the differential 5. The rotation of the input shaft 16 is output to the output shaft 17 after being shifted at a reduction ratio corresponding to the gear stage achieved by the transmission mechanism 15, and the output is input to the differential device 5.

  The power connection / disconnection clutch 2 connects the output shaft 12 of the engine 1 and the input shaft 16 of the automatic transmission 4 so that they can be connected / disconnected, an engine-side friction plate that rotates integrally with the output shaft 12, an input shaft 16 and a transmission-side friction plate that rotates integrally with 16. The power connection / disconnection clutch 2 can be switched between a fastening state in which the two friction plates are pressed against each other and a release state in which the pressure contact between the two friction plates is released. The power connection / disconnection clutch 2 is provided with an actuator (not shown) that drives the friction plates in the press-contact direction, and the driving force of the actuator is automatically increased or decreased according to the traveling state of the vehicle. One of the above-mentioned fastening state and the releasing state is achieved.

  In the engaged state of the power disconnection clutch 2, the torque of the output shaft 12 of the engine 1 is transmitted to the input shaft 16 of the automatic transmission 4 without loss by the two friction plates being pressed against each other with a strong force. And the input shaft 16 rotate together. In the disengaged state of the power disconnection clutch 2, the output shaft 12 and the input shaft 16 are brought into contact with each other by setting the pressure contact force of the friction plates to zero so that torque is not transmitted from the output shaft 12 to the input shaft 16. It is completely divided.

  The differential device 5 is a device for distributing the rotation of the output shaft 17 of the automatic transmission 4 to the left and right wheels 7, and allows the differential rotation of the left and right drive shafts 6 while allowing the output shaft 17 of the automatic transmission 4 to rotate. And a conventionally known differential gear mechanism for interlockingly connecting the drive shafts 6 to each other.

  The regenerative device 3 has a hydraulic pump motor 19 linked to the input shaft 16 of the automatic transmission 4 and a hydraulic circuit 20 for supplying and discharging oil to and from the hydraulic pump motor 19.

  The hydraulic pump motor 19 can be switched between a drive mode that operates as a motor that drives the input shaft 16 and a regenerative mode that operates as a pump driven by the input shaft 16 in accordance with oil supply / discharge control by the hydraulic circuit 20. Has been.

  For example, in the regeneration mode in which the hydraulic pump motor 19 operates as a pump, the hydraulic pump motor 19 is driven by the input shaft 16, and oil is pumped from the pump motor 19 to the hydraulic circuit 20 and stored in a pressure accumulation state. That is, the regenerative device 3 converts the rotational force of the input shaft 16 into hydraulic energy by a hydraulic pump motor 19 that operates as a pump, and stores the converted hydraulic energy in a hydraulic circuit 20 (an accumulator 22 described later).

  On the other hand, in the drive mode in which the hydraulic pump motor 19 operates as a motor, the hydraulic pump motor 19 is driven by the oil supplied from the hydraulic circuit 20, and the input shaft 16 is rotated by the hydraulic pump motor 19. That is, the regenerative device 3 operates the hydraulic pump motor 19 as a motor, and takes out the hydraulic energy stored in the hydraulic circuit 20 as work for rotating the input shaft 16.

  FIG. 2 is a circuit diagram showing details of the hydraulic circuit 20. As shown in the figure, the hydraulic circuit 20 includes an oil pan 21 that stores oil in a low pressure state, an accumulator 22 that stores oil in a pressure accumulation state (corresponding to “accumulator” in the claims), a hydraulic pump motor A suction passage 23 for sending the oil in the oil pan 21 to the hydraulic pump motor 19 when the regenerative mode 19 operates as a pump, and an oil discharged from the hydraulic pump motor 19 to the accumulator 22 when the regenerative mode is also used. A discharge passage 24 for sending, a return passage 25 connecting the discharge passage 24 and the suction passage 23, and for sending oil from the accumulator 22 to the hydraulic pump motor 19 in the drive mode in which the hydraulic pump motor 19 operates as a motor. Oil discharged from the hydraulic pump motor 19 in the supply passage 26 and also in the drive mode. A discharge passage 27 for sending to the oil pan 21, first and second direction switching valves 30, 31 for switching the oil circulation route, a check valve 32 provided in the middle of the discharge passage 24, and a return The first linear solenoid valve 33 provided in the middle of the passage 25 and the second linear solenoid valve 34 provided in the middle of the supply passage 26 are provided.

  The oil pan 21 is the same as an oil pan that stores hydraulic oil that circulates inside the automatic transmission 4. That is, in the automatic transmission 4, the operation used for driving the frictional engagement elements (the high clutch CL1 and the low clutch CL2, which will be described later) and lubricating the sliding portion is always in circulation. For this reason, an oil pan for storing the hydraulic oil is attached to the lower part of the automatic transmission 4. The oil pan 21 of the hydraulic circuit 20 is the same as the oil pan originally provided in the automatic transmission 4. For this reason, it can be said that the oil in the hydraulic circuit 20 is a part of the working oil that circulates in the automatic transmission 4.

  The accumulator 22 is a conventionally known bladder type accumulator, provided in a case for storing oil, a supply / discharge valve for controlling supply / discharge of oil to / from the case, and inside the case, and encloses gas inside. And a diaphragm. Such an accumulator 22 increases the pressure of the oil by compressing the sealed gas with the oil pumped from the hydraulic pump motor 19 into the case, and releases the high-pressure oil to the outside by opening the supply / discharge valve. Is possible.

  The first direction switching valve 30 selectively permits either an oil flow from the suction passage 23 toward the hydraulic pump motor 19 or an oil flow from the supply passage 26 toward the hydraulic pump motor 19. The second direction switching valve 31 selectively permits either an oil flow from the hydraulic pump motor 19 toward the discharge passage 24 or an oil flow from the hydraulic pump motor 19 toward the discharge passage 27. In accordance with the switching of the oil flow by these direction switching valves 30, 31, the hydraulic pump motor 19 is switched between a regeneration mode in which it operates as a pump and a driving mode in which it operates as a motor.

  FIG. 3A shows the flow of oil in the regenerative mode in which the hydraulic pump motor 19 operates as a pump. In the regenerative mode, the first / second directional switching valve 30 is configured so that the flow of oil from the suction passage 23 to the hydraulic pump motor 19 is allowed and the flow from the hydraulic pump motor 19 to the discharge passage 24 is allowed. , 31 are driven. As a result, the low pressure hydraulic pressure stored in the oil pan 21 is sucked into the hydraulic pump motor 19 through the suction passage 23, and the high pressure oil discharged from the hydraulic pump motor 19 is guided to the accumulator 22 through the discharge passage 24. . At this time, the return amount of oil from the discharge passage 24 to the suction passage 23 can be adjusted in accordance with the DUTY ratio of the first linear solenoid valve 33 provided in the return passage 25, and the hydraulic pressure is accordingly increased. It is possible to increase / decrease the work amount of the pump motor 19 as a pump. That is, as the amount of oil returned from the discharge passage 24 to the suction passage 23 is reduced, the amount of oil pumped from the hydraulic pump motor 19 to the accumulator 22 is increased, so that the work of the hydraulic pump motor 19 as a pump ( Load) increases. When the amount of work increases, the torque to be applied to the hydraulic pump motor 19 from the input shaft 16 of the automatic transmission 4 increases, so that a larger brake is applied to the input shaft 16.

  On the other hand, FIG. 3B shows the flow of oil in the drive mode in which the hydraulic pump motor 19 operates as a motor. In this drive mode, the first / second directional control valve 30 is configured so that the flow of oil from the supply passage 26 to the hydraulic pump motor 19 is allowed and the flow from the hydraulic pump motor 19 to the discharge passage 27 is allowed. , 31 are driven. Accordingly, high-pressure oil stored in the accumulator 22 is supplied to the hydraulic pump motor 19 through the supply passage 26, and oil discharged from the hydraulic pump motor 19 is guided to the oil pan 21 through the discharge passage 27. At this time, it is possible to adjust the amount of oil supplied from the accumulator 22 to the hydraulic pump motor 19 according to the DUTY ratio of the second linear solenoid valve 34 provided in the supply passage 26. It is possible to increase / decrease the work amount of the hydraulic pump motor 19 as a motor. That is, as the amount of oil supplied from the accumulator 22 to the hydraulic pump motor 19 increases, the work amount of the hydraulic pump motor 19 as a motor increases. When the work amount increases, the torque applied from the hydraulic pump motor 19 to the input shaft 16 of the automatic transmission 4 increases, so that the rotation of the input shaft 16 is further accelerated.

  As shown in FIG. 1, the transmission mechanism 15 of the automatic transmission 4 includes a transmission case C, a first gear set GS1 and a second gear set GS2 disposed inside the transmission case C, and first and second gear sets. It has a high clutch CL1 and a low clutch CL2 that are engaged or released to switch the power transmission path by the gear sets GS1, GS2.

  Each of the first and second gear sets GS1 and GS2 is a conventionally known planetary gear set, and includes a sun gear, a pinion, and a ring gear that mesh with each other, and a carrier that supports the pinion.

  The high clutch CL1 connects the predetermined rotation element in the first gear set GS1 and the input shaft 16 to each other, and the low clutch CL2 connects the predetermined rotation element in the second gear set GS2 and the input shaft 16 to each other. Yes.

  In the automatic transmission 4 of this embodiment including the transmission mechanism 15 having the above-described structure, a plurality of gear stages having different reduction ratios can be achieved according to the combination of engagement / release of the high clutch CL1 and the low clutch CL2. Has been. For example, when the position of the shift lever (shift position), which will be described later, is in the D range, the automatic transmission 4 is automatically adapted from at least two gears of the first speed and the second speed depending on the traveling state of the vehicle. The gear stage is selected. Specifically, the first speed is achieved by engaging the low clutch CL2 and releasing the high clutch CL1, and decelerating from the first speed by releasing the low clutch CL2 and engaging the high clutch CL1. A second gear with a small ratio is achieved.

  In this embodiment, only the first speed or the second speed is illustrated for simplicity of explanation, but the automatic transmission 4 has an arbitrary gear stage between the highest gear stage of the fourth speed or higher and the first speed. It can be an achievable multi-stage transmission. In this case, the speed change mechanism 15 includes a plurality of gear sets other than the first gear set GS1 and the second gear set GS2, and a plurality of friction engagement elements (clutch or brake) other than the high clutch CL1 and the low clutch CL2. And are included.

(2) Control System FIG. 4 is a block diagram showing a control system of the vehicle drive device of the present embodiment. The PCM 50 shown in the figure is a microprocessor for comprehensively controlling the engine 1, the regenerative device 3, and the automatic transmission 4, and includes a well-known CPU, ROM, RAM, and the like.

  Detection signals from various sensors are input to the PCM 50. For example, the engine 1 is provided with an engine rotation sensor SN1 that detects the rotation speed of the output shaft 12, that is, the engine rotation speed, and detection signals from the engine rotation sensor SN1 are sequentially input to the PCM 50. Further, the automatic transmission 4 is provided with an input shaft rotation sensor SN2 that detects the rotation speed of the input shaft 16, and detection signals from the input shaft rotation sensor SN2 are sequentially input to the PCM 50. Further, the vehicle includes a vehicle speed sensor SN3 that detects a traveling speed (vehicle speed) of the vehicle, and an accelerator sensor SN4 that detects an opening degree (accelerator opening degree) of an accelerator pedal (not shown) operated by a driver driving the vehicle. Similarly, a shift position sensor SN5 for detecting the position (shift position) of the shift lever (not shown) operated by the driver is provided, and detection signals from these vehicle speed sensor SN3, accelerator sensor SN4, and shift position sensor SN5 are also provided. Sequentially input to the PCM 50.

  The PCM 50 performs various determinations and calculations based on signals input from the sensors SN1 to SN5, and controls each control object included in the engine 1, the regenerative device 3, and the automatic transmission 4 for control. Output a signal. As functional elements for realizing such control, the PCM 50 includes an engine control unit 51 and a shift control unit 52 (a “first shift control unit” and a “second shift control unit” in the claims). Equivalent) and a regeneration control unit 53.

  The engine control unit 51 is electrically connected to an unillustrated injector (fuel injection valve), a spark plug, and the like provided in the engine 1, and the output torque of the engine 1 becomes an appropriate value according to a driver's request or the like. Control the injector and spark plug.

  The shift control unit 52 controls a flow of hydraulic oil flowing through the automatic transmission 4 to switch the engagement / release of each friction engagement element (the high clutch CL1 and the low clutch CL2). The solenoid valve is controlled so that an appropriate gear according to the running state of the vehicle can be obtained as the gear of the automatic transmission 4. The shift control unit 52 is electrically connected to an actuator that presses the friction plates of the power connection / disconnection clutch 2 together, and the power connection / disconnection clutch 2 is appropriately disconnected according to the shift position, the running state of the vehicle, and the like. The actuator is controlled so as to come into contact.

  The regenerative control unit 53 is electrically connected to the first and second directional switching valves 30 and 31 and the first and second linear solenoid valves 33 and 34 in the hydraulic circuit 20, and according to the traveling state of the vehicle and the like. The valves 30 to 34 are controlled so that the hydraulic pump motor 19 operates appropriately as a motor or a pump.

(3) Control at the time of downshifting Next, the PCM 50 (the engine control unit 51, the shift control unit 52, and the regeneration control unit 53) at the time of the downshift to switch the gear stage of the automatic transmission 4 from the second speed to the first speed. The control operation to be executed will be described using the flowchart of FIG. 5 and the time chart of FIG.

  When the control shown in FIG. 5 starts, the shift control unit 52 determines whether or not there is a request for a downshift to switch the gear stage of the automatic transmission 4 from the second speed to the first speed (step S1). For example, the speed change control unit 52 detects the engine speed, the vehicle speed, and the engine speed detected by the engine speed sensor SN1, the vehicle speed sensor SN3, and the accelerator sensor SN4 while the vehicle is traveling with the second speed selected as the gear stage. When at least one of the accelerator opening changes, and the condition determined by the combination of these values meets the condition for selecting the first speed, it is determined that a downshift request has been issued.

  In the time chart of FIG. 6, the time point when the request for the downshift is issued is t1. Prior to this time t1, since the second gear is selected as the gear stage, in the automatic transmission 4, the high clutch CL1 is engaged and the low clutch CL2 is released. That is, the high clutch CL1 is supplied with a high hydraulic pressure (line pressure) X for completely fastening it, and the hydraulic pressure supplied to the low clutch CL2 is zero. Further, the power disconnection clutch 2 is maintained in the engaged state before the time point t1. In this state, the driver includes the accelerator pedal relatively large, so that a downshift is requested at time t1.

  When it is determined YES in step S1 and it is confirmed that there is a request for downshift, the shift control unit 52 switches the power connection / disconnection clutch 2 from the engaged state to the released state (step S2). In other words, the shift control unit 52 controls the actuator of the power connection / disconnection clutch 2 so that the pressure contact force between the friction plates of the power connection / disconnection clutch 2 becomes zero, whereby the automatic transmission 4 from the output shaft 12 of the engine 1. The connection between them is released so that torque is not transmitted to the input shaft 16.

  In response to the request for the downshift, the regeneration control unit 53 switches the mode of the hydraulic pump motor 19 to the drive mode and operates the hydraulic pump motor 19 as a motor (step S3). That is, as shown in FIG. 3 (b), the regeneration control unit 53 performs the first and second operations so that the oil flows in the order of accumulator 22 → supply passage 26 → hydraulic pump motor 19 → discharge passage 27 → oil pan 21. By controlling the direction switching valves 30 and 31, the hydraulic pump motor 19 is operated as a motor that is rotated by high-pressure oil supplied from the accumulator 22.

  Further, in response to the request for downshift, the engine control unit 51 controls each part of the engine 1 so that the output torque of the engine 1 increases (step S4). That is, the engine control unit 51 increases the output torque of the engine 1 by performing control such as increasing the amount of fuel injected from the injector (fuel injection valve) into each cylinder of the engine 1.

  In the time chart of FIG. 6, almost simultaneously with the time t1 when the downshift is requested, the power connection / disconnection clutch 2 is released, and control for increasing the output torque of the engine 1 is started. The mode is switched to the drive mode. As the power disconnection clutch 2 is released, the output shaft 12 of the engine 1 becomes free (thus reducing the load on the engine 1), and the torque generated by the engine 1 itself is increased. The rotational speed of the shaft 12 (the solid line waveform in the third graph from the bottom) starts to rise relatively steeply from the time point t1. Further, the shaft torque of the hydraulic pump motor 19, more specifically, the torque applied from the hydraulic pump motor 19 to the input shaft 16 of the automatic transmission 4 rapidly increases positively from a value before time t 1 (here, zero). . Shortly after the time t1, the shaft torque of the hydraulic pump motor 19 increases to + V1, and thereafter is maintained at a constant value for a while. This positive torque (positive torque) indicates that the hydraulic pump motor 19 assists the rotation of the input shaft 16.

  As the power connection / disconnection clutch 2 is released at the time t1, the driving force of the engine 1 is not input to the input shaft 16 of the automatic transmission 4 thereafter. When the positive torque is applied to 16, the input torque to the input shaft 16 is maintained at the same level as before time t 1, and the rotation speed of the input shaft 16 (the one-dot chain line in the third graph from the bottom) Waveform) changes with the same tendency as before time t1. In FIG. 6, the vehicle acceleration is not particularly changed before and after the time point t1. The regenerative control unit 53 predetermines a positive torque (+ V1) to be applied to the input shaft 16 in order to drive the vehicle at the same acceleration as before the power disconnection clutch 2 is released, and the determined positive torque is determined by the hydraulic pump. The second linear solenoid valve 34 is controlled so as to be generated from the motor 19 to adjust the work amount of the hydraulic pump motor 19 as a motor.

  Next, the shift control unit 52 determines whether or not the rotational speed of the output shaft 12 of the engine 1 has increased to the synchronous rotational speed Nx that is the rotational speed corresponding to the reduction ratio of the gear stage (first speed) after the downshift. (Step S5). The synchronous rotation speed Nx can be obtained by calculation based on the reduction ratio obtained when the first gear is achieved and the current vehicle speed detected by the vehicle speed sensor SN3. Based on the comparison between the synchronous rotational speed Nx calculated in this way and the rotational speed of the output shaft 12 detected by the engine rotational sensor SN1, the shift control unit 52 determines that the rotational speed of the output shaft 12 is the synchronous rotational speed. It is determined whether or not Nx has been reached. In the time chart of FIG. 6, the time point when the rotational speed of the output shaft 12 reaches the synchronous rotational speed Nx is t2.

  When it is determined YES in step S5 and it is confirmed that the rotational speed of the output shaft 12 of the engine 1 has increased to the synchronous rotational speed Nx, the shift control unit 52 disengages the power disconnection clutch 2 from the released state to the engaged state. (Step S6). That is, the shift control unit 52 drives the actuator so that the friction plates of the power connection / disconnection clutch 2 are pressed against each other with a sufficient force, whereby the output shaft 12 of the engine 1 and the input shaft 16 of the automatic transmission 4 are The two are connected so that they rotate together.

  When the control of step S6 for engaging the power connection / disconnection clutch 2 is started as described above, the shift control unit 52 switches the high clutch CL1 from the engaged state to the released state almost simultaneously with this, and the low clutch CL2 is switched on. Switching from the released state to the fastened state (step S7). That is, the shift control unit 52 engages the high clutch CL1 by lowering the hydraulic pressure supplied to the high clutch CL1 from the line pressure X to zero and increasing the hydraulic pressure supplied to the low clutch CL2 from zero to the line pressure X. And release the low clutch CL2.

  Next, the shift control unit 52 determines whether or not the engagement of the low clutch CL2 has been completed (step S8). That is, the shift control unit 52 checks whether or not the hydraulic pressure supplied to the low clutch CL2 reaches the line pressure X based on the detection value of the hydraulic sensor built in the automatic transmission 4, and reaches the line pressure X. At this point, it is determined that the engagement of the low clutch CL2 has been completed. In the time chart of FIG. 6, the time point when the engagement of the low clutch CL2 is completed (the time point when the hydraulic pressure reaches the line pressure X) is t3. At almost the same time as t3, the release of the high clutch CL1 is completed (the hydraulic pressure becomes zero), and the engagement of the power disconnection clutch 2 is completed.

  When it is determined YES in step S8 and it is confirmed that the engagement of the low clutch CL2 is completed, the regenerative control unit 53 switches the mode of the hydraulic pump motor 19 from the drive mode to the regenerative mode and switches the hydraulic pump motor 19 on. Operate as a pump (step S9). That is, as shown in FIG. 3A, the regeneration control unit 53 performs the first and second operations so that oil flows in the order of the oil pan 21, the suction passage 23, the hydraulic pump motor 19, the discharge passage 24, and the accumulator 22. By controlling the direction switching valves 30 and 31, the hydraulic pump motor 19 is operated as a pump that sucks up oil from the oil pan 21 and pumps it. As the hydraulic pump motor 19 operates as a pump in this way, oil is pumped from the hydraulic pump motor 19 to the accumulator 22 and the pressure of the accumulator 22 is increased. In other words, the rotational force of the input shaft 16 is converted into hydraulic energy and stored in the accumulator 22 as hydraulic pressure.

  As the mode of the hydraulic pump motor 19 is switched to the regenerative mode as described above, in the time chart of FIG. 6, the shaft torque of the hydraulic pump motor 19 changes from positive to negative, which is the maximum value on the negative side. It has declined immediately. This negative torque (reverse torque) indicates that the hydraulic pump motor 19 is braking the rotation of the input shaft 16. The regenerative control unit 53 determines a reverse torque (−V2) for applying an appropriate brake to the input shaft 16 according to various conditions, and the first linear so that the determined reverse torque is generated from the hydraulic pump motor 19. The work of the hydraulic pump motor 19 as a pump is adjusted by controlling the solenoid valve 33. If the time required for the shaft torque of the hydraulic pump motor 19 to decrease from + V1 to -V2 cannot be ignored, the start of the control in step S9 (switching to the regeneration mode) is advanced by this required time. It is necessary. In this case, for example, the engagement completion timing (time point t3) of the clutch CL2 is predicted based on the rising state of the hydraulic pressure supplied to the low clutch CL2, and the required time (the shaft torque is reduced to −V2) from the predicted timing. The control in step S9 may be started at a timing that is advanced by an amount equivalent to the time required for the decrease.

  Next, the regeneration control unit 53 gradually reduces the work amount of the hydraulic pump motor 19 as a pump so that the reverse torque applied from the hydraulic pump motor 19 to the input shaft 16 gradually decreases (step S10). In the time chart of FIG. 6, the reverse torque that has increased to −V2 immediately after the completion time t3 of engagement of the low clutch CL2 gradually decreases and reaches zero at time t4. Thus, the downshift from the second speed to the first speed is completed.

(4) Operational Effects As described above, in the present embodiment, at the time of a downshift that lowers the gear position of the automatic transmission 4, for example, a downshift from the second speed to the first speed (see FIGS. 5 and 6). The power connection / disconnection clutch 2 that connects the output shaft 12 of the engine 1 and the input shaft 16 of the automatic transmission 4 is released, and the rotation speed of the output shaft 12 of the engine 1 is reduced by the reduction ratio after the downshift (first speed). The engine 1 is controlled so as to increase toward the synchronous rotational speed Nx corresponding to the engine speed, and the mode of the regenerative device 3 (more specifically, its hydraulic pump motor 19) is set to the drive mode so that the input shaft of the automatic transmission 4 A positive torque is applied to 16. Then, as the rotational speed of the output shaft of the engine 1 rises to the synchronous rotational speed Nx, the engagement pattern (high clutch CL1 and low clutch CL2) of the automatic transmission 4 is achieved at the first speed. CL1 release, CL2 engagement), and the power connection / disconnection clutch 2 is switched from the release state to the engagement state. According to such a configuration, there is an advantage that a rapid downshift of the automatic transmission 4 can be realized while maintaining energy efficiency satisfactorily.

  That is, in the above-described embodiment, the power connection / disconnection clutch 2 is first released during the downshift, and the output shaft 12 of the engine 1 is raised toward the synchronous rotation speed Nx in that state. It is possible to quickly and accurately increase the rotational speed of the output shaft 12 of the engine 1 that has become free as the motor is released to the synchronous rotational speed Nx. Further, since the mode of the hydraulic pump motor 19 is changed to the drive mode with the release of the power connection / disconnection clutch 2, a positive torque is applied from the hydraulic pump motor 19 to the input shaft 16 of the automatic transmission 4 disconnected from the engine 1. Thus, the acceleration of the vehicle can be maintained equal to the acceleration before the power disconnection clutch 2 is released. Further, since the power connection / disconnection clutch 2 is engaged after the rotation speed of the output shaft 12 of the engine 1 has increased to the synchronous rotation speed Nx, the rotation of the output shaft 12 of the engine 1 that has been sufficiently accelerated is 2 is transmitted to the input shaft 16 of the automatic transmission 4 via 2, the rotational speed of the input shaft 16 increases to the same rotational speed as the output shaft 12 of the engine 1 in a short time. For this reason, the operation of switching the engagement pattern of the frictional engagement element of the automatic transmission 4 for changing the gear position (that is, the operation of releasing the high clutch CL1 and engaging the low clutch CL2) is changed to the rotation increasing speed of the input shaft 16. It can be performed at a combined relatively fast speed, and the switching can be completed quickly to achieve a low gear position (first speed) after downshifting. In addition, such rapid switching of the engagement pattern reduces the slip loss of the friction engagement elements (the high clutch CL1 and the low clutch CL2), that is, the energy loss due to the frictional heat caused by the relative rotation of the friction plates. Means that. Therefore, according to the above-described embodiment, it is possible to shorten the time required for the downshift, and to reduce the slip loss and improve the energy efficiency.

  Further, in the above-described embodiment, the hydraulic pump motor 19 that has been switched to the drive mode with the release of the power connection / disengagement clutch 2 until the engagement of the low clutch CL2 is completed (that is, the switching of the engagement pattern is completed as shown in FIG. 6). (until t3), since the drive mode is maintained, the rotational speed of the input shaft 16 of the automatic transmission 4 is reduced by the action of the positive torque continuously applied from the hydraulic pump motor 19 to the input shaft 16 of the automatic transmission 4. The time required to increase to the same rotational speed as the output shaft 12 of the engine 1 (time from time t2 to time t3 in FIG. 6) can be further shortened. As a result, it is possible to further accelerate the downshift and reduce slip loss.

  In the above embodiment, since the mode of the hydraulic pump motor 19 is switched from the drive mode to the regenerative mode at the time when the engagement of the low clutch CL2 is completed (time t3 in FIG. 6), the hydraulic pump motor switched to the regenerative mode. By applying reverse torque (brake) from 19 to the input shaft 16 of the automatic transmission 4, it is possible to effectively suppress the occurrence of a shift shock in which the acceleration of the vehicle changes suddenly with an increase in the reduction ratio due to the downshift. it can.

  Further, since the hydraulic pump motor 19 is switched to the regenerative mode (mode that operates as a pump) to suppress shift shock, oil is pumped from the hydraulic pump motor 19 to the accumulator 22, so that every time a downshift is performed. The rotational force of the input shaft 16 can be converted into hydraulic energy and stored in the accumulator 22, and the stored energy can be taken out as work on another occasion. As described above, in the above embodiment, energy is not wasted for countermeasures against shift shocks and is recovered as reusable energy, so that the energy efficiency of the vehicle can be effectively improved. .

  For example, suppression of the shift shock can be achieved by retarding the ignition timing to temporarily reduce the output torque of the engine 1, but in this case, the fuel consumption performance of the engine 1 deteriorates with the ignition retard. There is a problem. On the other hand, when the regenerative brake is used as in the above embodiment, the regenerated energy can be reused and the ignition retard as described above becomes unnecessary. it can.

  In the above embodiment, the hydraulic pump motor 19 is controlled so that the reverse torque applied to the input shaft 16 from the hydraulic pump motor 19 switched to the regeneration mode gradually decreases after the engagement of the low clutch CL2. Therefore, unlike the case where, for example, the reverse torque to the input shaft 16 is suddenly reduced to zero, it is possible to prevent the rotational speed of the input shaft 16 from changing suddenly. Can be prevented from becoming unstable.

(5) Modification In the above embodiment, when a request for downshifting is issued, control for releasing the power disconnection clutch 2, control for switching the mode of the hydraulic pump motor 19 to the drive mode, and output shaft of the engine 1 Although the control to increase the rotational speed of 12 toward the synchronous rotational speed Nx is started almost at the same time, the start timing of each control does not necessarily have to be the same. For example, the switching to the drive mode of the hydraulic pump motor 19 and the increase in the rotational speed of the engine 1 may be started after a predetermined minute time has elapsed from the release of the power connection / disconnection clutch 2.

  In the above embodiment, the mode of the hydraulic pump motor 19 is driven until the switching of the engagement pattern of the friction engagement elements (the high clutch CL1 and the low clutch CL2) of the automatic transmission 4 is completed (until time t3 in FIG. 6). However, the hydraulic pump motor 19 only needs to be set to the drive mode at least during the period when the power connection / disconnection clutch 2 is released. You may cancel 19 drive modes.

  In the above embodiment, the regenerative device 3 including the hydraulic pump motor 19 and the accumulator 22 is provided as means for applying a positive torque or a reverse torque to the input shaft 16 of the automatic transmission 4. Can convert the rotational force of the input shaft into some reusable energy and store it (according to this, give reverse torque to the input shaft), and drive the input shaft using the stored energy ( It is only necessary to be able to apply a positive torque), and is not limited to the hydraulic regeneration device 3 as in the above embodiment. For example, the regenerative device is an electric regenerative device that can be switched between a regenerative mode in which the rotational force of the input shaft is converted into electric energy and stored, and a drive mode in which the input shaft is driven using the stored electric energy. May be. In this case, the regenerative device includes a motor generator that can be switched between a regeneration mode in which driving force is obtained from the input shaft to generate electric power and a driving mode in which the input shaft is driven, a charging mode in which electric power generated by the motor generator is stored, and electric power And a capacitor that can be switched to a discharge mode for supplying to the motor generator.

  Moreover, in the said embodiment, although the engine 1 which consists of a spark ignition type engine was mounted in the vehicle as a power source (main power sources other than the hydraulic pump motor 19) in order to drive a vehicle, it is restricted to such an engine 1. In addition, various engines such as a diesel engine and a rotary engine can be used as a power source.

DESCRIPTION OF SYMBOLS 1 Engine 2 Power connection / disconnection clutch 3 Regenerative device 4 Automatic transmission 7 Wheel 12 (Engine) output shaft 16 (Automatic transmission) input shaft 19 Hydraulic pump motor 22 Accumulator (accumulator)
51 engine control unit 52 shift control unit (first shift control unit, second shift control unit)
53 Regenerative control part CL1 High clutch (friction engagement element)
CL2 Low clutch (friction engagement element)
Nx Synchronous rotation speed

Claims (5)

An engine having an output shaft ;
An automatic transmission that has an input shaft that is connected to the output shaft of the engine in a connectable manner and transmits the rotation of the input shaft to the wheel side while shifting the speed;
A power connection / disconnection clutch that can be switched between an engagement state in which the output shaft of the engine and an input shaft of the automatic transmission are integrally rotated and a release state in which the connection is released;
A regenerative device linked to the input shaft of the automatic transmission and capable of switching between a regenerative mode for converting the rotational force of the input shaft into energy and storing it, and a drive mode for driving the input shaft using the stored energy When,
A first shift control unit for releasing the power connection / disengagement clutch at the time of a downshift to switch the gear of the automatic transmission from a high gear to a low gear;
An engine control unit for increasing the rotational speed of the output shaft of the engine toward a synchronous rotational speed corresponding to a reduction ratio after downshifting after releasing the power disconnection clutch;
A regenerative control unit that applies a positive torque to the input shaft of the automatic transmission with the mode of the regenerative device as the drive mode during the release period of the power disconnection clutch;
In response to the rotation speed of the output shaft of the engine increasing to the synchronous rotation speed, the friction engagement element of the automatic transmission is switched to an engagement pattern in which the low gear stage is achieved, and the power connection / disconnection clutch is A vehicle drive device comprising: a second shift control unit to be fastened. The vehicle drive device according to claim 1,
The regenerative control unit maintains the mode of the regenerative device in the drive mode until the switching of the fastening pattern of the frictional engagement element is completed. The vehicle drive device according to claim 2,
The regenerative control unit switches the mode of the regenerative device from the drive mode to the regenerative mode when the switching of the engagement pattern of the frictional engagement element is completed, and applies reverse torque to the input shaft of the automatic transmission. The vehicle drive device characterized by the above-mentioned. In the vehicle drive device according to claim 3,
The regenerative control unit is configured so that the reverse torque applied to the input shaft from the regenerative device switched to the regenerative mode gradually approaches zero after completion of the engagement pattern switching of the frictional engagement element. The vehicle drive device characterized by controlling. In the vehicle drive device according to any one of claims 1 to 4,
The regenerative device has a hydraulic pump motor linked to the input shaft, and a pressure accumulator in which oil supplied to and discharged from the hydraulic pump motor is stored.
The hydraulic pump motor is driven by the input shaft and operates as a pump that pumps oil to the pressure accumulator, and a drive that operates as a motor that drives the input shaft upon receiving oil supply from the pressure accumulator A vehicle drive device characterized by being switchable between modes.

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