JP2013107446A - Control device of hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device of a hybrid vehicle which generates a proper deceleration speed at a down-shift even if a brake operation and a manual down-shift are superposed on each other, and can avoid the deterioration of the durability of a battery.SOLUTION: In the control device of the hybrid vehicle comprising a manual shift means which changes speeds between and among a plurality of speed change ratios on the basis of a manual shift operation, and a brake means which controls a brake force of the vehicle by the regeneration torque of an electric motor and the friction brake torque of a friction brake on the basis of the brake operation, there is arranged a regeneration torque limit means (steps S2, S3) which limits the regeneration torque at a normal-time regeneration limit value for preventing the excessive charge of a power accumulator, and limits the regeneration torque at a regeneration limit value lower than the normal-time regeneration limit value prior to the execution of the down-shift by the manual shift when the manual shift operation is executable.

Description

  The present invention relates to a control apparatus for a hybrid vehicle including an internal combustion engine and an electric motor having a power generation function as a driving force source for traveling, and in particular, manual shift that allows selective shifting by a driver's operation is possible. The present invention relates to a control device for a hybrid vehicle.

  A hybrid vehicle is a vehicle equipped with an internal combustion engine such as a gasoline engine or a diesel engine as a driving force source, and an electric motor having a power generation function such as a motor / generator. By utilizing the characteristics of the internal combustion engine and the electric motor, The fuel consumption can be improved, and the exhaust gas can be reduced. For example, the internal combustion engine can be operated at an operating point with good combustion efficiency, and the driving torque required for the vehicle can be applied by an electric motor. Furthermore, it is possible to regenerate energy during deceleration and use the electric power generated at that time for traveling. Therefore, it is possible to improve the fuel efficiency and reduce the exhaust gas while satisfying the demand for traveling. An example of an invention relating to such a hybrid vehicle is described in Patent Document 1.

  The invention described in Patent Document 1 sets the required deceleration torque based on the shift position when the driver is traveling with the accelerator off for the purpose of improving shift feeling in a hybrid vehicle capable of manual shifting. When the shift position is not changed by the driver, the motor is controlled so that the vehicle decelerates with the requested deceleration torque set with the accelerator off, and the shift position is changed by the driver. At the time of the change, the electric motor is controlled so that the vehicle travels at a reduced speed by the deceleration torque obtained by adding the torque fluctuation for changing the shift position to the required deceleration torque set when the accelerator is off. Further, in Patent Document 1, when the shift position is changed to the downshift side, the torque fluctuation for changing the shift position tends to increase as the shift position changed to the downshift side becomes smaller as the shift stage. It is described that the control is performed so that the regenerative braking torque by the electric motor becomes larger as the shift stage is smaller.

  Patent Document 2 describes an invention relating to a vehicle and a control device therefor that are intended to suppress a shock that tends to occur when a regenerative braking force by an electric motor is reduced during a braking operation in a hybrid vehicle. In the invention described in Patent Document 2, the required regenerative braking force for the motor and the required friction braking force for the friction braking means are set based on the required braking force according to the brake operation by the driver and a predetermined distribution constraint. And the required regenerative braking force when the accelerator is off and the above described regenerative braking force when the brake is being operated in the accelerator off state. The target driving force is set based on the temporary target driving force that is the sum of the required driving force when the accelerator is off. When at least the power output to the axle is within a predetermined range including 0, the target driving force is set to change gently based on the temporary target driving force, and the brake operation is performed in the accelerator-off state. In this case, the electric motor is controlled so as to output the power based on the target driving force to the axle, and the friction braking means is controlled so as to obtain the required friction braking force. Patent Document 2 describes that the upper limit of the regenerative braking force by the electric motor is set based on the battery input / output limit, the rated torque of the electric motor, and the like.

  Patent Document 3 discloses a vehicle that aims to improve drivability by adjusting the coast deceleration according to the strength of the driver's coast deceleration request when coasting with an accelerator opening operation. An invention relating to a coasting deceleration control device is described. In Patent Document 3, it is determined that the driver intends to increase the coast deceleration if the required time from the accelerator release to the depression of the brake is within the set time. The shorter the required time, the shorter the coast target driving force. Is described, that is, the regenerative braking torque by the motor / generator is increased. It also describes that a brake pedal force equivalent value when the brake is depressed is detected, and that the coast target drive force is increased as the brake pedal force equivalent value is increased, that is, the regenerative braking torque by the motor / generator is increased.

  Patent Document 4 describes an invention related to a regenerative cooperative control device for the purpose of preventing a sudden brake disengagement feeling in a vehicle that is driven by an electric motor. In Patent Document 4, when the limit of regenerative power by the electric motor is expected based on the remaining battery capacity data, the ratio of regenerative braking by the electric motor is reduced in advance, and the friction between the brake disk and the brake pad is reduced. The point which keeps the ratio of braking high is indicated.

JP 2006-160238 A JP 2008-236825 A JP 2007-168565 A JP 2010-200557 A

  As described above, the invention described in Patent Document 1 improves the shift feeling in a hybrid vehicle capable of manual shift, for example, a general vehicle equipped with a stepped automatic transmission using an engine as a driving force source, The purpose is to realize the same shift feeling. And it is comprised so that an appropriate deceleration can be generated especially at the time of downshift by manual shift. Even in a hybrid vehicle that does not have a stepped mechanical speed change mechanism, a reduction torque (regenerative torque or The braking torque can be applied to the drive wheels to generate the deceleration expected by the driver. That is, at the time of downshift by manual shift, by increasing the regenerative torque by the electric motor, it is possible to realize the same shift feeling as when the engine brake is applied to the vehicle.

  On the other hand, conventional hybrid vehicles including those described in Patent Document 1 described above have a regenerative braking force generated by a regenerative torque generated by an electric motor and a braking device (friction such as a disc brake or a drum brake mounted on a wheel). The braking force can be obtained in two ways, that is, the friction braking force by the brake). Normally, the braking force is determined based on the distribution of the regenerative braking force and the friction braking force set in advance according to the driver's braking operation. For example, as described in Patent Document 2, in the conventional hybrid vehicle, in order to protect the electric motor and the battery, the upper limit of the regenerative torque (regenerative limit value) generated by the electric motor based on the rating of the electric motor and the battery. Is set. In the hybrid vehicle, the distribution of the regenerative braking force and the friction braking force is basically given priority to the regenerative braking force. However, when the regenerative torque reaches the upper limit, the vehicle is mainly controlled by the friction braking force. It is set to generate power.

  Therefore, in a hybrid vehicle capable of performing manual shift as described in Patent Document 1 described above, when the vehicle is braked by a driver's brake operation, the manual operation is performed with the regenerative torque reaching the upper limit. When the downshift by the shift is executed, the regenerative torque cannot be increased by the electric motor, and the deceleration expected by the driver may not be realized by the downshift.

  For example, as shown in the time chart of FIG. 10, when a brake operation by the driver such as a foot brake operation is performed at time ta, the regenerative torque by the electric motor and the braking torque by the friction brake are controlled to increase, thereby Vehicle deceleration increases. Then, when the increased regenerative torque reaches the regenerative limit value L as shown in FIGS. 10 and 11 (time tb), after that, the desired deceleration is obtained mainly by the braking torque by the friction brake. In addition, the electric motor and the friction brake are controlled. In this state, when a downshift by manual shift as shown at times tc and td is executed, the regenerative torque by the motor has already reached the upper limit, so an increase in deceleration due to the regenerative torque cannot be expected. That is, the regenerative torque by the electric motor is used up by the brake operation by the driver, and there is no room for generating the regenerative torque at the time of downshift. Therefore, the deceleration of the vehicle changes only slightly due to the change in the friction torque caused by the change in the engine speed, and an increase in the deceleration accompanying the downshift can hardly be expected.

  In response to this, in order to realize the deceleration expected at the time of downshift, the upper limit of the regenerative torque by the motor is canceled or the upper limit is expanded, so that the deceleration is increased by the regenerative torque at the time of downshift Can be made. However, in that case, the battery will be overcharged, thereby reducing the durability of the battery.

  In this way, in a conventional hybrid vehicle that is configured so that manual shift can be performed, if the brake operation and the downshift by manual shift are performed in parallel following the driver's brake operation, the downshift is performed. There is still room for improvement in order to achieve both a desired appropriate deceleration and avoiding a decrease in battery durability.

  The present invention has been made paying attention to the above technical problem, and even when the driver's brake operation and the downshift by manual shift are executed in a superimposed manner, Therefore, it is an object of the present invention to provide a control device for a hybrid vehicle that can generate an appropriate deceleration expected by the driver or intended by the driver and avoid a decrease in battery durability.

  In order to achieve the above object, an invention according to claim 1 is a hybrid vehicle having an internal combustion engine and an electric motor as driving force sources, and is driven by shifting output torque from the driving force source to a plurality of gear ratios. Transmission means for transmitting to the wheel; manual shift means for executing the shift based on a manual shift operation by the driver; brake operation detection means for detecting presence or absence of a brake operation by the driver and a brake operation amount; and the brake A hybrid having a braking means for controlling a braking force of the hybrid vehicle by a regenerative torque generated by regenerative control of the electric motor based on an operation and a friction braking torque generated by controlling an operation of the friction braking device In the vehicle control device, whether or not the manual shift operation can be executed The manual shift determining means for determining and defining the upper limit of the regenerative torque with a normal-time regenerative limit value set based on the charge / discharge capacity of the power storage device that transfers power between the motor and the manual shift When it is determined that the operation can be performed, the upper limit of the regenerative torque is defined by a regenerative limit value that is lower than the normal-time regenerative limit value prior to execution of the downshift by the manual shift. And a regenerative torque limiting means.

  The invention according to claim 2 is the invention according to claim 1, wherein the regenerative torque limiting means is configured such that the required braking torque set according to the brake operation amount does not exceed the normal-time regenerative limit value. The upper limit of the regenerative torque is defined by a normal-time regenerative limit value, and when the required braking torque exceeds the normal-time regenerative limit value, the value is set to be lower as the brake operation amount is larger. A control device comprising means for defining an upper limit of the regenerative torque by a regenerative limit value.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the regenerative torque limiting means includes means for setting the regenerative limit value for each of the plurality of speed ratios set by the manual shift operation. It is a control device characterized by including.

  According to the first aspect of the present invention, in the hybrid vehicle capable of braking by the regenerative torque of the electric motor and braking by the friction braking torque of the friction braking device and capable of manual shift operation, the manual shift operation by the driver is executed. When it is determined that the condition is possible, the upper limit of the regenerative torque is limited by a regenerative limit value that is lower than the normal-time regenerative limit value set to protect the power storage device. That is, when the manual shift operation can be executed, the upper limit value of the regenerative torque is changed to a value lower than the normal time regenerative limit value. Therefore, when braking by the regenerative torque is executed by the driver's brake operation, a downshift by manual shift is further executed, and it is necessary to generate a braking force corresponding to the downshift by the regenerative torque. In this case, the regenerative torque can be increased within a range not exceeding the normal-time regenerative limit value. That is, as described above, in order to increase the regenerative torque when the downshift is executed by setting the regenerative limit value lower than the normal time regenerative limit value prior to the downshift by the manual shift. You can leave an allowance. Therefore, even when the driver's brake operation and the downshift by manual shift are executed in a superimposed manner, an appropriate braking force expected or intended by the driver is generated during the downshift. be able to. And even in that case, since the regenerative torque does not exceed the normal-time regenerative limit value, it is possible to reliably avoid a decrease in durability of the power storage device.

According to the invention of claim 2, when the manual shift operation can be executed, the regeneration limit value set to a value lower than the normal-time regeneration limit value is further set based on the brake operation amount of the driver. Is done. Specifically, in the range where the required braking torque determined according to the amount of brake operation does not exceed the normal regeneration limit value, the upper limit of the regenerative torque is defined by the normal regeneration limit value, and the required braking torque is the normal regeneration limit value. In the range exceeding the regeneration limit value, the regeneration limit value is set so that the upper limit of the regeneration torque becomes lower as the brake operation amount becomes larger. Therefore, when the brake operation amount is relatively small, the upper limit of the regenerative torque is defined by the normal regenerative limit value. That is, the upper limit value of the regenerative torque is set as high as possible. For this reason, when the brake operation amount is relatively small, for example, a regenerative power as large as possible can be generated during a slow or normal brake operation with a high execution frequency, and a charging power amount for the power storage device is ensured. be able to. When the brake operation amount is relatively large, the upper limit of the regenerative torque is defined by the regenerative limit value set so that the value decreases as the brake operation amount increases. For this reason, when the brake operation amount is relatively large, for example, during a sudden brake operation that is less frequent than in a normal brake operation, it is possible to leave a margin that can be further increased in the regenerative torque by the electric motor. When a downshift by manual shift is executed following the driver's braking operation, the regenerative torque can be increased to generate the braking force expected by the driver.

  According to the invention of claim 3, as described above, the regeneration limit value set to a value lower than the normal-time regeneration limit value when the manual shift operation is executable is changed by the manual shift operation. It is appropriately set for each of a plurality of gear ratios. For this reason, the control for setting the upper limit of the regenerative torque corresponding to the case where the brake operation as described above and the downshift by manual shift are executed in a superimposed manner is more appropriately performed in accordance with the shift state of the hybrid vehicle. Can be executed

1 is a schematic diagram illustrating an example of a configuration and a control system of a hybrid vehicle to be controlled in the present invention. It is a flowchart for demonstrating an example of control by the control apparatus of this invention. It is a schematic diagram for demonstrating the regeneration limit value set by control by the control apparatus of this invention shown in FIG. FIG. 3 is a schematic diagram for explaining a regeneration limit value for each gear position set by control by the control device of the present invention shown in FIG. 2. FIG. 3 is a time chart for explaining the behavior of a hybrid vehicle when control by the control device of the present invention shown in FIG. 2 is executed. FIG. It is a flowchart for demonstrating the other example of control by the control apparatus of this invention. It is a schematic diagram for demonstrating the regeneration limit value set by control by the control apparatus of this invention shown in FIG. It is a schematic diagram for demonstrating the regeneration limit value for every gear stage set by control by the control apparatus of this invention shown in FIG. It is a time chart for demonstrating the behavior of the hybrid vehicle at the time of performing control by the control apparatus of this invention shown in FIG. It is a time chart for demonstrating the example of the conventional control in a hybrid vehicle. It is a schematic diagram for demonstrating the normal time regeneration limit value set by the conventional control shown in FIG.

  Next, the present invention will be specifically described with reference to the drawings. FIG. 1 shows the configuration and control system of a hybrid vehicle to be controlled in the present invention. That is, the hybrid vehicle Ve shown in FIG. 1 is a so-called two-motor type hybrid vehicle, and includes the internal combustion engine 1 and the two electric motors 2 and 3 as a driving force source, and the electric power of the internal combustion engine 1 is supplied to the electric motor 2. And the output shaft 4.

  The internal combustion engine 1 is a power engine that outputs power by burning fuel such as a gasoline engine, a diesel engine, or a natural gas engine. The example shown in FIG. 1 includes an electronically controlled throttle valve and an electronically controlled fuel injection device that can electrically control a load such as a throttle opening and a fuel injection amount. It is equipped with a gasoline engine that can set the optimum operating point with the best fuel efficiency by electrically controlling the rotational speed with respect to the load. In the following description, the internal combustion engine 1 is referred to as the engine 1.

  Each of the electric motors 2 and 3 is an electric motor having a function of either one or both of a motor and a generator. In the example shown in FIG. 1, a motor that has both a function as a motor and a function as a generator. A generator is installed. Hereinafter, in the description of this embodiment, the electric motors 2 and 3 are referred to as a first motor / generator (MG1) 2 and a second motor / generator (MG2) 3.

  A planetary gear mechanism 5 having a differential action is provided as a power split mechanism for splitting the power of the engine 1 into the first motor / generator 2 and the output shaft 4. In the example shown in FIG. 1, a single pinion type planetary gear mechanism is employed in which a pinion gear disposed between a sun gear 5s and a ring gear 5r is held by a carrier 5c so as to be able to rotate and revolve. The engine 1 is connected to the carrier 5c of the planetary gear mechanism 5, the first motor / generator 2 is connected to the sun gear 5s, and the output shaft 4 is connected to the ring gear 5r. When the planetary gear mechanism 5 performs a differential action, the rotational speed of the engine 1 changes according to the rotational speed of the first motor / generator 2. Therefore, the first motor / generator 2 can control the engine speed of the engine 1. Drive wheels 8 are connected to the output shaft 4 through a gear transmission mechanism 6 and a differential 7 so that power can be transmitted. The driving wheel 8 and other wheels (driven wheels) (not shown) are equipped with a friction brake 9 that generates a so-called friction braking force by the action of a friction force such as a disc brake or a drum brake.

  On the other hand, the second motor / generator 3 is connected to the output shaft 4 via the planetary gear mechanism 10. In the example shown in FIG. 1, the planetary gear mechanism 6 employs a single pinion type planetary gear mechanism in which a pinion gear disposed between the sun gear 10s and the ring gear 10r is held by a carrier 10c so as to be able to rotate and revolve. The second motor / generator 3 is connected to the sun gear 10s of the planetary gear mechanism 10, and the output shaft 4 is connected to the ring gear 10r. The carrier 10c is fixed so as not to rotate. Accordingly, the planetary gear mechanism 10 functions as a speed reduction mechanism that decelerates the output torque of the second motor / generator 3 and transmits it to the output shaft 4.

  As described above, each of the first motor / generator 2 and the second motor / generator 3 is configured by a known synchronous motor having both functions of an electric motor and a generator. The first motor / generator 2 and the second motor / generator 3 are connected to a power storage device 13 via inverters 11 and 12, respectively. That is, the inverter 11 controls the power generation amount of the first motor / generator 2 and the torque or rotation speed when the first motor / generator 2 functions as an electric motor. The inverter 12 controls the power generation amount of the second motor / generator 3. The second motor / generator 3 is configured to control the torque or the number of rotations when it functions as an electric motor.

  The first motor / generator 2 and the second motor / generator 3 are configured to be able to mutually supply electric power between them via the inverters 11 and 12. That is, the electric power generated by one of the first motor / generator 2 and the second motor / generator 3 can be consumed by the other motor / generator. For example, when the first motor / generator 2 is driven by the output of the engine 1 to function as a generator, the electric power generated by the first motor / generator 2 is supplied to the second motor / generator 3, The two-motor generator 3 can function as an electric motor. Accordingly, part of the power output from the engine 1 is once converted into electric power by the first motor / generator 2, then converted again into power by the second motor / generator 3, and the power is transmitted to the output shaft 4. It is configured to be able to.

  An electronic control unit (ECU) 14 for controlling the operating state of the engine 1 and the motor generators 2 and 3 is provided. The electronic control unit 14 includes, for example, a vehicle speed sensor 15 that detects the vehicle speed of the vehicle Ve, for example, an accelerator opening sensor 16 that detects a driver's accelerator operation by an accelerator pedal or an accelerator lever, for example, a driver's brake by a brake pedal. A brake sensor (or brake switch) 17 for detecting an operation, for example, a shift position sensor 18 for detecting a manual shift operation of a driver by a shift lever or a shift switch, or an engine rotation for detecting a rotation speed of an output shaft of the engine 1 Detection signals from various sensor devices such as a number sensor (not shown) and a resolver (not shown) for detecting the rotational speed of the rotation shafts of the motor generators 2 and 3 are input. On the other hand, the electronic control device 14 outputs a signal for controlling the engine 1, a signal for controlling the motor / generators 2 and 3 (that is, controlling the inverters 11 and 12 and the power storage device 13), and the like. It is configured as follows.

  In the hybrid vehicle Ve to be controlled in the present invention, the driver operates a shift lever, a shift switch, a shift paddle, or the like to change the speed to any of a plurality of gear stages or gear ratios intended by the driver. That is, it is configured such that a manual shift that selectively performs a shift by a driver's operation can be executed. For example, when the D (drive) position is selected as the shift position, the hybrid vehicle travels under automatic shift control. When the M (manual) position or the S (sport) position is selected, operations such as a shift switch and a shift paddle are enabled, and a manual shift by the driver can be performed. In addition, even when switching from the D position to the B (engine brake) position is set to be effective, it is possible to realize a downshift by manual shift or a deceleration state corresponding to the downshift by switching to the B position. It becomes.

  Furthermore, the hybrid vehicle Ve to be controlled in the present invention is configured to generate an appropriate braking force corresponding to an engine brake of a general engine-driven vehicle when downshifting by manual shift. ing. The hybrid vehicle Ve has a configuration that does not have a stepped transmission mechanism that is mounted on a general engine-driven vehicle. However, when the second motor / generator 3 is regeneratively controlled, the hybrid vehicle Ve can perform a downshift. The braking torque (regenerative torque) equivalent to the engine brake in the engine-driven vehicle can be applied to the drive wheels 8 to generate the deceleration expected by the driver in the hybrid vehicle Ve.

  In addition, the hybrid vehicle Ve according to the present invention has a so-called regenerative braking force generated by a regenerative torque generated by an electric motor (in this example, the second motor / generator 3) and a friction mounted on a wheel, as in a conventional hybrid vehicle. Two types of braking force, that is, so-called friction braking force by the brake 9 can be obtained. The distribution between the regenerative braking force and the friction braking force is set based on a preset distribution ratio, a driver's brake operation amount, and the like. Further, the regenerative braking force is generated with priority over the friction braking force. Specifically, the regenerative torque generated and increased by the second motor / generator 3 prevents the power storage device 13 from being overcharged and avoids a decrease in durability due to the power storage device 13 being overcharged. Therefore, the hybrid vehicle Ve is braked preferentially by the regenerative braking force until the normal-time regenerative limit value L is set. After the increased regenerative torque reaches the normal regeneration limit value L, further increase of the regenerative torque is prohibited, and the braking of the hybrid vehicle Ve is mainly performed by the friction braking force by the friction brake 9. Is configured to be performed.

  As described above, the hybrid vehicle Ve that is the subject of the present invention has a configuration capable of performing a manual shift by the driver. When the downshift by the manual shift is performed, the hybrid vehicle Ve is driven by the second motor / generator 3. The regenerative torque is increased to control the braking force to act on the hybrid vehicle Ve. In the hybrid vehicle Ve having such a configuration, as described above, when the hybrid vehicle Ve is braked by the driver's brake operation, the regenerative torque by the second motor / generator 3 becomes the normal-time regenerative limit value L. If the downshift by the manual shift is executed in the reached state, the regenerative torque by the second motor / generator 3 cannot be further increased. That is, when the normal regeneration limit value L is set uniformly as in the prior art, there is a possibility that the deceleration and braking force expected by the driver cannot be obtained during downshift by manual shift. there were.

  Therefore, in the control device for the hybrid vehicle Ve according to the present invention, the durability of the power storage device 13 is maintained even when the brake operation and the downshift by the manual shift are executed after the driver's brake operation. The following control is performed so that an appropriate deceleration can be applied during downshifting without causing a decrease in performance. An example of the control is shown in the flowchart of FIG. The routine shown in this flowchart is repeatedly executed every predetermined short time. In FIG. 2, first, it is determined whether or not the current state of the hybrid vehicle Ve is under a condition that allows manual shift (step S1). The conditions that allow manual shift are, for example, that the shift position is set to the M position or S position, and that the operation of a shift lever or shift switch for executing manual shift is set to an effective state. This is a state in which the gear stage or the gear ratio can be selectively changed according to the driver's intention.

  Therefore, for example, when the D position, R (reverse) position, or N (neutral) position is selected as the shift position, or when switching from the D position to the B position is disabled, Since manual shift is not executed, a negative determination is made in step S1. And this routine is once complete | finished, without performing subsequent control.

  On the other hand, if the M position or S position is selected as the shift position, or if switching from the D position to the B position is set to be effective, the conditions for executing manual shift are satisfied. It can be determined that Accordingly, in this case, an affirmative determination is made in step S1, and the process proceeds to step S2, where the regeneration limit value La corresponding to the manual shift is previously set lower than the normal state prior to execution of the downshift by the manual shift. Is set. That is, as shown in FIG. 3, the limit value that defines the upper limit of the regenerative torque by the second motor / generator 3 under the condition that the manual shift can be performed satisfies the above-described condition for executing the manual shift. It is lowered to a value smaller (close to 0) than the normal-time regenerative limit value L set at normal time, and set again as the regenerative limit value La corresponding to manual shift. In addition, since the ratio of the friction braking torque generated by the friction brake 9 is increased by the amount that the upper limit of the regenerative torque by the second motor / generator 3 is reduced by the regenerative limit value La, the upper limit of the regenerative torque is reduced. Even in such a case, the required braking force set based on the brake operation amount of the driver can be generated without excess or deficiency by the regenerative torque by the second motor / generator 3 and the friction braking torque by the friction brake 9. Can do.

  In this way, the regeneration limit value La corresponding to the manual shift is smaller than the normal-time regeneration limit value L set at the normal time, that is, the normal-time regeneration limit value L, prior to the downshift by the manual shift. When the downshift by the manual shift of the driver is executed in a state where the second motor / generator 3 outputs a predetermined regenerative torque by the driver's brake operation by being set in advance to a value close to 0 In addition, it is possible to avoid a situation in which the regenerative torque output by the second motor / generator 3 has already reached the upper limit and cannot cope with the increase in the regenerative torque accompanying the downshift. That is, by setting the regeneration limit value La lower than the normal-time regeneration limit value L as described above, the brake operation and the downshift by the manual shift are superimposed and executed following the driver's brake operation. Even in such a case, it is possible to leave a margin that can be output to the regenerative torque by the second motor / generator 3 and to apply an appropriate braking force corresponding to the downshift by the regenerative torque of the second motor / generator 3. Can be generated.

  Further, as described above, the regenerative limit value La is set to a value smaller than the normal-time regenerative limit value L set for protection of the power storage device 13, so that the regenerative torque of the second motor / generator 3 When the braking force corresponding to the downshift is generated, the regenerative torque does not exceed the normal regeneration limit value L. Therefore, even when the second motor / generator 3 is regeneratively controlled to increase the regenerative torque at the time of downshift, it is reliably avoided that the power storage device 13 is overcharged by the regenerative power at that time. The durability of the power storage device 13 can be prevented from being lowered.

  As described above, when the regenerative limit value La is set in step S2, the regenerative limit value Lan for each gear position is set for the regenerative limit value La (step S3). The regenerative limit value Lan is the upper limit value of the regenerative torque that is applied when the shift stage of the hybrid vehicle Ve set when the driver's brake operation is executed is downshifted in the nth speed. It is. Therefore, if the hybrid vehicle Ve in this embodiment has a configuration capable of setting six speeds or gear ratios from the first speed to the sixth speed, in this step S3, as shown in FIG. As the regeneration limit value Lan for each gear position, six values of regeneration limit values La6 to La1 are set.

  Specifically, each regenerative limit value La6, to La1 is based on the regenerative limit value La set in step S2, and the regenerative limit value La6 applied at the sixth speed, which is the highest speed stage, is the smallest value. The regenerative limit value La1 applied at the first speed, which is the lowest speed stage, is set to the largest value within a range not exceeding the normal-time regenerative limit value L so that the smaller the applied gear stage, the larger the value. Is set. As described above, in the present invention, the braking force generated in the hybrid vehicle Ve by increasing the regenerative torque of the second motor / generator 3 during the downshift simulates engine braking in a general engine-driven vehicle. It is. Therefore, the downshift when the gear position is small (that is, the gear ratio is large) requires a braking force corresponding to a large engine brake. For this reason, the regenerative limit values La6 to La1 are set so that the regenerative limit values La6 to La1 become larger as the applied gear is smaller, that is, a larger regenerative torque can be generated. In the configuration of the hybrid vehicle Ve shown in this embodiment, the downshift from the first speed is not further performed. Therefore, the regeneration limit value La1 applied at the first speed is the same as the normal time regeneration limit value L. Is set to a value.

  In this way, in addition to the regeneration limit value La set in step S2, the regeneration limit values La6 to La1 corresponding to the respective speeds are set in step S3, so that more precise control is performed. When a downshift by a manual shift is executed following a brake operation, a more appropriate braking force corresponding to the engine brake can be generated. Note that step S3 can be omitted to simplify the control.

  As described above, when the regenerative limit value La and the regenerative limit values La6 to La1 are set in steps S2 and S3, the process proceeds to step S4, and whether or not the manual shift executable condition is continuously satisfied. Is determined. If it is determined affirmative in step S4 because the manual shift executable condition is continuously established, the process returns to the above-described step S2 and the previous control is executed in the same manner. That is, while the execution condition for manual shift continues, the regenerative limit value La and the regenerative limit values La6 to La1 set in steps S2 and S3 are held, and a downshift due to manual shift is performed. It corresponds to the case where it is executed.

  On the other hand, if it is determined negative in step S4 because the condition for enabling manual shift has not been established, this routine does not need to be executed, so this routine is temporarily terminated.

  The behavior of the hybrid vehicle Ve when the control shown in the flowchart of FIG. 2 is executed as described above is shown in the time chart of FIG. When the hybrid vehicle Ve is traveling at the fifth speed and a brake operation by the driver such as a foot brake operation is performed at time t1, first, control is performed so that the regenerative torque by the second motor / generator 3 increases. As a result, the deceleration of the hybrid vehicle Ve increases. Since the hybrid vehicle Ve is traveling at the fifth speed at this time, the regeneration limit value La5 is set in advance as the upper limit of the regeneration torque.

  When the increased regenerative torque reaches the regenerative limit value La5 at time t2, the subsequent increase of the regenerative torque by the second motor / generator 3 is stopped. That is, the value of the regenerative torque by the second motor / generator 3 is held at the regenerative limit value La5. After time t2, the second motor / generator 3 and the friction brake 9 are controlled so that a desired deceleration can be obtained mainly by the braking torque of the friction brake 9. That is, the distribution of the friction braking force by the friction brake 9 is set to 0 until the regenerative torque by the second motor / generator 3 reaches the regenerative limit value La5. Then, after the regenerative torque reaches the regenerative limit value La5 and is limited, the regenerative braking force by the regenerative torque and the friction braking force by the friction brake 9 are appropriately distributed, and the desired values are determined by the regenerative braking force and the friction braking force. The deceleration to be obtained can be obtained.

  As described above, when the regenerative torque by the second motor / generator 3 is limited by the regenerative limit value La5, a downshift by a manual shift from the fifth speed to the fourth speed is executed at time t3. Prior to execution of the downshift, the upper limit of the regenerative torque is changed to the regeneration limit value La4 for the fourth speed. The regenerative torque by the second motor / generator 3 is increased with the regenerative limit value La4 as the upper limit. That is, the regenerative torque by the second motor / generator 3 is increased until the value of the regenerative torque reaches the regenerative limit value La4 at time t4. Similarly, when a downshift by manual shift from the fourth speed to the third speed is executed at time t5, similarly, prior to the execution of the downshift, the upper limit of the regenerative torque is the regeneration limit value of the third speed. The regeneration torque by the second motor / generator 3 is increased with the regeneration limit value La3 as the upper limit.

  Therefore, even if the downshift by the manual shift is executed in a state where the increase in the regenerative torque by the second motor / generator 3 is restricted as described above, the upper limit of the regenerative torque is changed to the increase side. Accordingly, the regenerative torque by the second motor / generator 3 can be increased and output as described above. In other words, during the downshift, the braking force can be generated in the hybrid vehicle Ve by the regenerative torque by the second motor / generator 3.

  The flowchart of FIG. 6 shows another control example of the present invention. In the example shown in FIG. 6, the control of steps S2 'and S3' is executed instead of the control of steps S2 and S3 in the flowchart of FIG. That is, in the example shown in FIG. 2 described above, when it is determined that a manual shift operation by the driver is possible, the regeneration torque regeneration limit value La is set to protect the power storage device 13. In contrast to the control that is preset to a value lower than the normal regeneration limit value L, the example shown in FIG. 6 shows that the regeneration torque regeneration limit value Lb is set in advance from the regeneration limit value L. Is an example of control in which the value is set to a low value and set according to the amount of brake operation by the driver.

  In the flowchart of FIG. 6, since the execution condition for manual shift is satisfied, an affirmative determination is made in step S1, and when the process proceeds to step S2 ′, the manual shift is executed in advance prior to the downshift by manual shift. A regeneration limit value Lb corresponding to the shift is set. This regenerative limit value Lb is a value set lower than the normal time regenerative limit value L that is set at the normal time when the execution condition for manual shift is not satisfied, similar to the above-described regenerative limit value La, It is set based on the brake operation amount of the driver.

  Specifically, as shown in FIG. 7, a regenerative limit value Lb that defines the upper limit of the regenerative torque by the second motor / generator 3 under conditions where manual shift can be performed is a normal-time regenerative limit that is set during normal times. It is set within a range not exceeding the value L. More specifically, when the brake operation amount is relatively small, the regeneration limit value Lb is set so that the upper limit of the regenerative torque is higher (away from 0) as the brake operation amount is larger. When the brake operation amount after the point at which the regenerative limit value Lb reaches the normal regeneration limit value L (the point of the brake operation amount α in FIG. 7) is relatively large, the regenerative torque increases as the brake operation amount increases. The regenerative limit value Lb is set so that the upper limit of becomes lower (closer to 0).

  Therefore, when the brake operation amount is relatively small and the required braking torque set in accordance with the brake operation amount is less than the normal regeneration limit value L, the regenerative torque by the second motor / generator 3 is the normal regeneration limit. Until the value L is reached, the hybrid vehicle Ve is braked so that the required braking torque is realized by the regenerative torque. When the brake operation amount is relatively large and the required braking torque exceeds the normal regeneration limit value L, the brake operation amount is requested by the regeneration torque whose upper limit is limited by the regeneration limit value Lb and the friction braking torque by the friction brake 9. The hybrid vehicle Ve is braked so that the braking torque is realized.

  As described above, the regeneration limit value Lb corresponding to the manual shift is smaller than the normal-time regeneration limit value L set in the normal time in advance before the downshift by the manual shift, that is, the normal-time regeneration limit value. By setting the value closer to 0 than L, the second motor generator can be used even when the brake operation of the driver is followed by the downshift by manual shift, following the driver's brake operation. 3 can be left in the regenerative torque, and an appropriate braking force corresponding to the downshift can be generated by the regenerative torque of the second motor / generator 3.

  Further, as described above, the regenerative limit value Lb is set to a value smaller than the normal-time regenerative limit value L set for protection of the power storage device 13, so that the regenerative torque of the second motor / generator 3 When the braking force corresponding to the downshift is generated, the regenerative torque does not exceed the normal regeneration limit value L. Therefore, even when the second motor / generator 3 is regeneratively controlled to increase the regenerative torque at the time of downshift, it is reliably avoided that the power storage device 13 is overcharged by the regenerative power at that time. The durability of the power storage device 13 can be prevented from being lowered.

  Furthermore, when the regeneration limit value Lb corresponding to the manual shift is set according to the driver's brake operation amount as described above, for example, at the time of a sudden brake operation that is less frequent than the normal brake operation. That is, when the brake operation amount is relatively large, it is possible to leave a margin that can be output to the regenerative torque by the second motor / generator 3. Therefore, the regenerative torque can be increased when the downshift by manual shift is executed following the driver's brake operation, and the deceleration expected by the driver can be realized. When the brake operation is performed frequently or at a moderate or normal braking operation, that is, when the brake operation amount is relatively small, the normal regeneration limit value L or the relatively large regeneration limit value L close to the normal regeneration limit value L is used. The upper limit of regenerative torque is regulated by the limit value Lb. Therefore, as much regenerative power as possible can be generated during normal frequent brake operation, and the amount of charge power for the power storage device 13 can be secured.

  As described above, when the regeneration limit value Lb is set in step S2 ', the regeneration limit value Lbn for each gear position is set for the regeneration limit value Lb (step S3'). The regenerative limit value Lbn is downshifted in a state where the gear position of the hybrid vehicle Ve set when the driver's brake operation is executed is the nth speed, similarly to the above-described regenerative limit value Lan. This is the upper limit value of the regenerative torque applied in this case. Therefore, if the hybrid vehicle Ve in this embodiment has a configuration capable of setting six speeds or gear ratios from the first speed to the sixth speed, in this step S3 ′, as shown in FIG. In addition, six values of regeneration limit values Lb6 to Lb1 are set as the regeneration limit value Lbn for each gear position.

  Specifically, each regenerative limit value Lb6, -Lb1 is the smallest regenerative limit value Lb6 applied at the sixth speed, which is the highest speed stage, based on the regenerative limit value Lb set in step S2 '. The regenerative limit value Lb1 applied at the first speed, which is the lowest speed stage, is the largest value within a range not exceeding the normal time regenerative limit value L, and the smaller the applied gear stage, the larger the value. In addition, the value is set to be smaller as the brake operation amount of the driver increases. In this embodiment, since there is no further downshift from the first speed, the regeneration limit value Lb1 applied at the first speed is set to the same value as the normal-time regeneration limit value L.

  In this way, in addition to the regeneration limit value Lb set in step S2 ′, the regeneration limit values Lb6 and Lb1 corresponding to the respective shift speeds are set in step S3 ′, so that a more precise value is obtained. Control can be executed, and when a downshift by a manual shift is executed following a brake operation, a more appropriate braking force corresponding to the engine brake can be generated. Note that this step S3 'can be omitted to simplify the control.

  When the regenerative limit value Lb and the regenerative limit values Lb6 to Lb1 are set in steps S2 ′ and S3 ′ as described above, the process proceeds to step S4, and the same control as in the flowchart of FIG. Is done.

  The behavior of the hybrid vehicle Ve when the control shown in the flowchart of FIG. 6 is executed is shown in the time chart of FIG. When the hybrid vehicle Ve is traveling at the fifth speed and a brake operation by the driver such as a foot brake operation is performed at time t11, first, control is performed so that the regenerative torque by the second motor / generator 3 increases. As a result, the deceleration of the hybrid vehicle Ve increases. Since the hybrid vehicle Ve is traveling at the fifth speed at this time, the regeneration limit value Lb5 is set in advance as the upper limit of the regeneration torque.

  When the increased regenerative torque reaches the regenerative limit value L at time t12 in the initial stage of braking where the brake operation amount is still small, the upper limit of the regenerative torque by the second motor / generator 3 thereafter depends on the brake operation amount. It is regulated by the regeneration limit value Lb5 that is set. At this time, the amount of brake operation gradually increases. Therefore, after this time t12, the regenerative torque by the second motor / generator 3 is gradually decreased in accordance with the increase of the amount of brake operation. Then, as the increase in the brake operation amount ends at time t13, the decrease in the regenerative torque is also stopped. That is, the value of the regenerative torque by the second motor / generator 3 is held at the regenerative limit value Lb5. Further, after time t12, the second motor / generator 3 and the friction brake 9 are controlled so that a desired deceleration can be obtained mainly by the braking torque of the friction brake 9. That is, also in this case, the distribution of the friction braking force by the friction brake 9 is set to zero until the regenerative torque by the second motor / generator 3 reaches the regenerative limit value La5. Then, after the regenerative torque reaches the regenerative limit value La5, the regenerative braking force by the regenerative torque and the friction braking force by the friction brake 9 are appropriately distributed, and a desired deceleration is generated by the regenerative braking force and the friction braking force. Can be obtained.

  As described above, when the regenerative torque by the second motor / generator 3 is limited by the regenerative limit value Lb5, when a downshift by manual shift from the fifth speed to the fourth speed is executed at time t14, the regeneration is performed. The upper limit of the torque is changed to the regeneration limit value Lb4 for the fourth speed. The regenerative torque by the second motor / generator 3 is increased with the regenerative limit value Lb4 as the upper limit. That is, the regenerative torque by the second motor / generator 3 is increased until the value of the regenerative torque reaches the regenerative limit value Lb4 at time t15. Similarly, when downshift by manual shift from the fourth speed to the third speed is executed at time t16, the upper limit of the regenerative torque is similarly changed to the regenerative limit value Lb3 for the third speed, and the regenerative limit is set. With the value Lb3 as the upper limit, the regenerative torque by the second motor / generator 3 is increased. Note that the regeneration limit values Lb4 and Lb3 in this case are set to a constant value according to the value of the brake operation amount because the corresponding brake operation amount is a constant value without increasing or decreasing. Yes.

  Therefore, even if the downshift by the manual shift is executed in a state where the increase in the regenerative torque by the second motor / generator 3 is restricted as described above, the upper limit of the regenerative torque is changed to the increase side. Accordingly, the regenerative torque by the second motor / generator 3 can be increased and output as described above. In other words, during the downshift, the braking force can be generated in the hybrid vehicle Ve by the regenerative torque by the second motor / generator 3.

  As described above, the hybrid vehicle control device according to the present invention is set to protect the power storage device 13 when it is determined that the manual shift operation by the driver can be performed. The upper limit of the regenerative torque by the second motor / generator 3 is limited by the regenerative limit values La and Lb that are lower than the normal-time regenerative limit value L. That is, when the manual shift operation can be performed, the upper limit value of the regenerative torque by the second motor / generator 3 is changed to a value lower than the normal-time regenerative limit value L. Therefore, when braking by the regenerative torque is executed by the driver's brake operation, a downshift by manual shift is further executed, and it is necessary to generate a braking force corresponding to the downshift by the regenerative torque. In this case, the regenerative torque can be increased in a range not exceeding the normal time regenerative limit value L.

  That is, before the downshift by the manual shift as described above, the regeneration limit values La and Lb having values lower than the normal regeneration limit value L are set, so that the regenerative torque is reduced when the downshift is executed. It is possible to leave a margin for increase. Therefore, even when the driver's braking operation and the downshift by manual shift are executed in a superimposed manner, the braking force expected by the driver or the appropriate braking force intended by the driver during the downshift is applied. Can be generated. And even in that case, since the regenerative torque does not exceed the normal-time regenerative limit value L, it is possible to reliably avoid a decrease in durability of the power storage device 13 due to overcharge.

  Here, the relationship between the above-described specific example and the present invention will be briefly described. The functional means for executing step S1 corresponds to the “manual shift determining means” in the present invention, and steps S2, S3 and S2 ′. , S3 ′ corresponds to the “regenerative torque limiting means” in the present invention.

  In the specific example described above, the hybrid vehicle that is the target of driving force control according to the present invention includes the engine 1 as an internal combustion engine, and the first motor / generator 2 and the second motor / generator 3 as electric motors. The configuration of the two-motor type hybrid vehicle has been described as an example. However, for example, a hybrid vehicle including an engine and one motor / generator may be used. In short, a hybrid vehicle having at least an internal combustion engine such as a gasoline engine or a diesel engine and an electric motor such as a motor or a motor / generator as a driving force source for generating the driving force of the vehicle, a so-called manual A hybrid vehicle configured to be able to perform a shift can be an object of control in the present invention.

  DESCRIPTION OF SYMBOLS 1 ... Engine (internal combustion engine; E / G), 2 ... 1st motor generator (electric motor; MG1), 3 ... 2nd motor generator (electric motor; MG2), 8 ... Drive wheel, 9 ... Friction brake (friction braking) Device), 14 ... an electronic control unit (ECU), 15 ... a vehicle speed sensor, 16 ... an accelerator opening sensor, 17 ... a brake sensor (brake switch), 18 ... a shift position sensor, Ve ... a hybrid vehicle.

Claims (3)

A hybrid vehicle using an internal combustion engine and an electric motor as a driving force source, based on shifting means for shifting output torque from the driving force source to a plurality of gear ratios and transmitting it to driving wheels, and a manual shift operation by a driver Manual shift means for executing the shift, brake operation detecting means for detecting the presence or absence of the brake operation by the driver and the amount of brake operation, and regenerative power generated by regenerative control of the electric motor based on the brake operation. A control device for a hybrid vehicle, comprising: braking means for controlling the braking force of the hybrid vehicle by a friction braking torque generated by controlling the torque and the operation of the friction braking device;
Manual shift determining means for determining whether the manual shift operation is possible or not;
The upper limit of the regenerative torque is defined by a normal-time regenerative limit value that is set based on the charge / discharge capacity of the power storage device that transfers power to and from the motor, and under the conditions under which the manual shift operation can be performed. Regenerative torque limiting means for prescribing an upper limit of the regenerative torque with a regenerative limit value lower than the normal-time regenerative limit value prior to execution of the downshift by the manual shift when determined to be present A hybrid vehicle control device.
The regenerative torque limiting means regulates the upper limit of the regenerative torque with the normal-time regenerative limit value when the required braking torque set according to the brake operation amount does not exceed the normal-time regenerative limit value, Means for defining an upper limit of the regenerative torque with the regenerative limit value set so that the larger the brake operation amount, the lower the value when the required braking torque exceeds the normal-time regenerative limit value; The control apparatus of the hybrid vehicle of Claim 1 characterized by these.
  3. The control apparatus for a hybrid vehicle according to claim 1, wherein the regenerative torque limiting means includes means for setting the regenerative limit value for each of the gear ratios set by the manual shift operation.

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