JP2014159238A - Control unit of hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control unit of a hybrid vehicle capable of suppressing degradation in drivability occurring when acceleration is requested.SOLUTION: When a running mode of an engine is set to partial cylinder running and a power dividing mechanism is in a non-differential state, if an acceleration request exceeding a predetermined criterion is received, a control unit of the present invention implements all-cylinders running switching control under which the running mode of the engine is switched to all-cylinders running, and differential state switching control under which the power dividing mechanism is switched to a differential state. At an unrestricted time at which a motor torque is not restricted based on an output restriction on a battery, the pieces of control are concurrently implemented in order to control a first motor generator so that an engine speed can rise. Thereafter, an output torque is augmented. At a restricted time at which the motor torque is restricted, after the all-cylinders driving switching control is implemented, the output torque is augmented with the differential mechanism held in the non-differential state. Thereafter, the differential state switching control is implemented in order to augment the output torque.

Description

  The present invention relates to a control device applied to a hybrid vehicle including an engine and a motor / generator as a driving power source.

  A control device applied to a hybrid vehicle having a differential mechanism that distributes engine torque to the first motor / generator and the output unit and capable of locking the first motor / generator coupled to the differential mechanism Is known (Patent Document 1).

JP 2009-222105 A

  In recent years, in order to improve the fuel consumption of an engine, a cylinder deactivation engine capable of deactivating a part of a plurality of cylinders has been developed. Application of such a cylinder deactivation engine as an engine of a hybrid vehicle capable of locking a motor / generator has not been sufficiently studied. When the engine performs partial cylinder operation, the absolute torque of the engine decreases. Therefore, when a high acceleration request is received while the engine is performing partial cylinder operation, it is necessary to stop partial cylinder operation and switch to full cylinder operation. Further, when the first motor / generator is locked and the differential mechanism is switched to the non-differential state, the movement of the engine operating point is limited as compared with the differential state, so that it is difficult to sufficiently draw out the engine power. Therefore, when strong acceleration is required, it is preferable to switch the differential mechanism from the non-differential state to the differential state. If the differential mechanism is switched from the non-differential state to the differential state, the engine speed can be increased by driving the first motor / generator.

  Therefore, when the engine performs partial cylinder operation and the differential mechanism receives a high acceleration request in a non-differential state, the engine operation mode is switched from partial cylinder operation to full cylinder operation, and the differential mechanism It is conceivable that the engine speed is increased by switching the state from the non-differential state to the differential state and driving the first motor / generator. However, output limits are set for the batteries that supply power to the first motor generator and the second motor generator. When the motor torque output from the first motor / generator or the second motor / generator is limited based on the output limit of the battery, the torque of the first motor / generator is insufficient and the engine speed is quickly increased. There is a possibility that the acceleration of the vehicle is delayed without being able to.

  Therefore, an object of the present invention is to provide a control device for a hybrid vehicle that can suppress deterioration in drivability when acceleration is requested even in a situation where the motor torque is limited by the output limit of the battery.

  The control device according to the present invention includes a plurality of cylinders, a partial cylinder operation in which some of the plurality of cylinders are deactivated and the remaining cylinders are operated, and all of the plurality of cylinders are operated. An engine capable of performing cylinder operation, a first motor / generator, an output unit for transmitting torque to drive wheels, and a difference in distributing torque of the engine to the first motor / generator and the output unit; A power mechanism, a second motor / generator coupled to the output unit, a battery capable of supplying power to the first motor / generator and the second motor / generator, and a state of the differential mechanism, And a lock means capable of switching between a differential state in which the torque is distributed to the first motor / generator and the output unit and a non-differential state in which the distribution is stopped In a hybrid vehicle control device that is applied to both and limits the motor torque output from the first motor / generator or the second motor / generator based on the output limit of the battery, the operation mode of the engine is the part In the case of cylinder operation and when the differential mechanism is in the non-differential state, the engine operation mode is changed from the partial cylinder operation to the full cylinder operation when an acceleration request exceeding a predetermined reference is received. And an all-cylinder operation switching control for switching to a differential state switching control for switching the state of the differential mechanism from the non-differential state to the differential state, and increasing the output torque output from the output unit A mode switching control unit, wherein the motor switching torque is not limited by the motor torque limiting unit. In this case, the differential state switching control and the all-cylinder operation switching control are performed, and the output torque is increased after controlling the first motor / generator so as to increase the engine speed. When limited by torque limiting means, after performing the all-cylinder operation switching control, the differential mechanism remains in the non-differential state to increase the output torque, and then performs the differential state switching control. The output torque is increased (claim 1).

  When the motor torque of the first motor / generator is limited based on the output limit of the battery, the motor torque is insufficient, so that the increase in the engine speed by the first motor / generator is delayed. For this reason, if the output torque is increased after waiting for an increase in the engine speed when the motor torque is limited, the rise of the output torque is delayed and the drivability at the time of an acceleration request is deteriorated. According to the control device of the present invention, when the motor torque is limited, the output torque is first increased after switching the engine operation mode from the partial cylinder operation to the full cylinder operation. Therefore, the output torque can be raised earlier than increasing the output torque after waiting for the engine speed to increase as described above. Thereby, even in a situation where the motor torque is limited, it is possible to suppress deterioration in drivability at the time of requesting acceleration.

  As one aspect of the control device of the present invention, the mode switching control unit simultaneously performs the differential state switching control and the all-cylinder operation switching control when the motor torque is not limited by the motor torque limiting unit. The output torque may be increased after the differential state switching control and the all-cylinder operation switching control are performed and the first motor / generator is controlled to increase the engine speed (Claim 2). . According to this aspect, when the motor torque is not limited by the motor torque limiting means, the differential state switching control and the all-cylinder operation switching control are performed at the same time, so that the completion of both controls is accelerated and the engine speed is increased. The time to increase is faster than if not implemented at the same time. For this reason, the rise of the output torque is further accelerated. Note that the simultaneous execution of the differential state switching control and the all cylinder operation switching control includes not only the case where the execution periods of the respective controls coincide with each other, but also the case where the execution periods of the respective controls partially overlap.

  As described above, according to the present invention, when the motor torque is limited, the output torque can be raised earlier than when the output torque is increased after waiting for the engine speed to rise. Thereby, even in a situation where the motor torque is limited, it is possible to suppress deterioration in drivability at the time of requesting acceleration.

The figure which showed the whole structure of the vehicle to which the control apparatus of one form of this invention was applied. The figure which showed the mode which the vehicle of FIG. 1 implements at the time of hybrid mode. The time chart which showed the control result concerning one form of the present invention with the comparative example. 6 is a flowchart illustrating an example of a control routine according to an embodiment of the present invention.

  As shown in FIG. 1, the vehicle 1 is configured as a hybrid vehicle in which a plurality of power sources are combined. The vehicle 1 includes an engine 3 and two motor generators 4 and 5 as driving power sources. The engine 3 is configured as an in-line four-cylinder internal combustion engine including four cylinders 10. The engine 3 can perform partial cylinder operation in which two of the four cylinders 10 are deactivated and the remaining two are operated in addition to the full cylinder operation in which all four cylinders 10 are operated. The engine 3 that performs the partial cylinder operation corresponds to being downsized to a low displacement engine.

  The engine 3 and the first motor / generator 4 are connected to a power split mechanism 6 as a differential mechanism. The first motor / generator 4 has a stator 4a and a rotor 4b. The first motor / generator 4 functions as a generator that generates power by receiving the power of the engine 3 distributed by the power split mechanism 6 and also functions as an electric motor driven by AC power. Similarly, the second motor / generator 5 includes a stator 5a and a rotor 5b, and functions as an electric motor and a generator, respectively. Each motor / generator 4, 5 is connected to a battery 16 via a motor control device 15. The motor control device 15 converts the electric power generated by each motor / generator 4, 5 into direct current and stores it in the battery 16, and converts the electric power of the battery 16 into alternating current and supplies it to each motor / generator 4, 5.

  The power split mechanism 6 is configured as a single pinion type planetary gear mechanism. The power split mechanism 6 is a planetary that holds a sun gear S as an external gear, a ring gear R as an internal gear arranged coaxially with the sun gear S, and a pinion P meshing with these gears S and R so as to be able to rotate and revolve. Carrier C. The engine torque output from the engine 3 is transmitted to the planetary carrier C of the power split mechanism 6. The rotor 4 b of the first motor / generator 4 is connected to the sun gear S of the power split mechanism 6. Torque output from the power split mechanism 6 via the ring gear R is transmitted to the output gear train 20. The output gear train 20 functions as an output unit for transmitting torque to the drive wheels 18. The output gear train 20 includes an output drive gear 21 that rotates integrally with the ring gear R of the power split mechanism 6, and an output driven gear 22 that meshes with the output drive gear 21. A second motor / generator 5 is connected to the output driven gear 22 via a gear 23. That is, the second motor / generator 5 is connected to an output gear train 20 as an output unit via a gear 23. The gear 23 rotates integrally with the rotor 5 b of the second motor / generator 5. Torque output from the output driven gear 22 is distributed to the left and right drive wheels 18 via the differential device 24.

  The power split mechanism 6 is provided with a motor lock mechanism 25 as a lock means. The motor lock mechanism 25 divides the state of the power split mechanism 6 into a differential state in which the torque of the engine 3 is distributed to the first motor / generator 4 and the output gear train 20 and a non-differential state in which the distribution is stopped. You can switch between them. The motor lock mechanism 25 is configured as a wet multi-plate type brake mechanism. The motor lock mechanism 25 is switched between an engaged state in which the rotation of the rotor 4b of the first motor / generator 4 is prevented and a released state in which the rotation of the rotor 4b is allowed. Switching between the engaged state and the released state of the motor lock mechanism 25 is performed by a hydraulic actuator (not shown). When the motor lock mechanism 25 is operated to the engaged state, the rotation of the rotor 4b of the first motor / generator 4 is prevented. Thereby, the rotation of the sun gear S of the power split mechanism 6 is also prevented. For this reason, the distribution of the torque of the engine 2 to the first motor / generator 4 is stopped, and the power split mechanism 6 enters a non-differential state.

  Control of each part of the vehicle 1 is controlled by an electronic control unit (ECU) 30 configured as a computer. The ECU 30 performs various controls on the engine 3, the motor / generators 4 and 5, the motor lock mechanism 25, and the like. Hereinafter, main control performed by the ECU 30 in relation to the present invention will be described. Various information on the vehicle 1 is input to the ECU 30. For example, the rotational speed and torque of each motor / generator 4, 5 are input to the ECU 30 via the motor control device 15. The ECU 30 also includes an output signal of an accelerator opening sensor 32 that outputs a signal corresponding to the amount of depression of the accelerator pedal 31, an output signal of a vehicle speed sensor 33 that outputs a signal corresponding to the vehicle speed of the vehicle 1, and a first signal. An output signal of a temperature sensor 34 that outputs a signal corresponding to the temperature of the motor / generator 4 is input. The ECU 30 calculates the required driving force requested by the driver with reference to the output signal of the accelerator opening sensor 32 and the output signal of the vehicle speed sensor 33, and performs various operations so that the system efficiency for the required driving force is optimized. The vehicle 1 is controlled while switching modes. For example, in the low load region where the thermal efficiency of the engine 3 is reduced, the EV mode in which the combustion of the engine 3 is stopped and the second motor / generator 5 is driven is selected. When the torque is insufficient with only the engine 3, the hybrid mode is selected in which the engine 3 and the second motor / generator 5 are used as a driving source for traveling.

  When the hybrid mode is selected, the ECU 30 sets the state of the power split mechanism 6 to the differential state and uses the power of the split engine 3 to generate power with the first motor / generator 4 and the power The state of the dividing mechanism 6 is switched to the non-differential state by operating the motor lock mechanism 25 to stop the distribution of the power of the engine 3 to the first motor / generator 4 and to output the power of the engine 3 to the output gear train 20. Switch to non-differential operation mode according to the situation. The switching from the differential operation mode to the non-differential operation mode is performed, for example, when the first motor / generator 4 exceeds the allowable limit and becomes high temperature or when the differential operation mode is performed, the first motor / generator 4 is switched. This is carried out when the lock permission condition is satisfied, for example, when so-called power circulation in which the rotation is negative is to be avoided.

  As described above, the engine 3 can perform partial cylinder operation and full cylinder operation. Therefore, as shown in FIG. 2, in the hybrid mode, (1) the differential operation mode in which the engine 3 is operated in all cylinders, (2) the differential operation mode in which the engine 3 is operated in partial cylinders, and (3) the engine 3 Is a non-differential operation mode in which all cylinders are operated, and (4) a non-differential operation mode in which the engine 3 is partially cylinder-operated exists. These modes are switched according to the required driving force. This embodiment is a process of switching from the mode (4) to the mode (1) when an acceleration request exceeding a predetermined reference is received during the non-differential operation mode of the partial cylinder operation (4). There is a feature in the control to be implemented in. The degree of the acceleration request is determined based on whether or not the standard set for the operation physical quantity such as the depression amount and the depression speed of the accelerator pedal 31 is exceeded. The ECU 30 acquires an operation physical quantity for the accelerator pedal 31 based on the output signal of the accelerator opening sensor 33, and determines that an acceleration request exceeding a predetermined reference is made when the operation physical quantity exceeds the reference. In the process of switching from the mode (4) to the mode (1), the ECU 30 makes no difference between the all-cylinder operation switching control for switching the operation mode of the engine 3 from the partial cylinder operation to the all cylinder operation and the state of the power split mechanism 6. Differential state switching control for switching from the dynamic state to the differential state is performed to increase the output torque output from the gear train 20.

  The battery 16 is preset with input restrictions and output restrictions in order to prevent overcharge and overdischarge. The power generation amount is adjusted so that the power generated by the second motor / generator 5 does not exceed the input limit of the battery 16 by the regenerative control. Further, when driving the first motor / generator 4 and the second motor / generator 5, the first motor / generator 4 and the second motor / generator 5 output such that the power consumption does not exceed the output limit of the battery 16. Motor torque to be limited. When the motor torque is limited based on the output limit of the battery 16, the motor torque is insufficient with respect to the torque that should be output. Therefore, the use of the first motor / generator 4 is restricted in the process in which the ECU 30 switches from the mode (4) to the mode (1) to increase the output torque. Therefore, in this embodiment, in the process of switching from the mode (4) to the mode (1), the control content is changed between when the motor torque is limited and when it is not limited based on the output limit of the battery 16. ing.

  FIG. 3 is a time chart showing an example of the control result of this embodiment together with a comparative example. When the motor torque is not limited, when the ECU 30 receives an acceleration request exceeding a predetermined reference, the ECU 30 switches the operation mode of the engine 3 from partial cylinder operation to all cylinder operation at time t0, and power splitting. Differential state switching control for switching the state of the mechanism 6 from the non-differential state to the differential state is performed simultaneously to switch from the mode (4) to the mode (1). Then, the first motor / generator 4 is driven to increase the engine speed to a predetermined level. When the engine speed reaches a predetermined level, the output torque is increased at time t1a. The output torque is increased by increasing the engine torque and the motor torque of the second motor / generator 5. Thereby, the output torque reaches the target value that satisfies the acceleration request at time t2a.

  On the other hand, when the motor torque is limited, the motor torque of the first motor / generator 4 can be increased even if an attempt is made to increase the engine speed after switching from the mode (4) to the mode (1). Is lacking. Therefore, in the comparative example, after the all-cylinder operation switching control and the differential state switching control are performed at time t0, it is necessary to increase the engine speed by the engine 3 itself. Become. Therefore, the time t1b at which the engine speed reaches a predetermined level is delayed and the rise of the output torque is delayed. That is, in the comparative example, after the acceleration request is received, the output torque remains steady for a period from time t0 to time t1b. Thereafter, the output torque increases and reaches the target value at time t2b. In the case of the comparative example, the driver feels that the period during which the output torque is steady as a non-reaction period, and thus drivability deteriorates.

  On the other hand, in the control of the present embodiment, the ECU 30 temporarily switches from the mode (4) to the mode (2) by switching the engine operation mode from partial cylinder operation to full cylinder operation at time t0. Then, the ECU 30 increases the engine torque and increases the output torque in the mode (2) in which the non-differential state is maintained. In the example of FIG. 3, the output torque is increased to a predetermined value that is smaller than the target value of the output torque. Then, the ECU 30 performs the differential state switching control at time t1′c to switch from the mode (2) to the mode (1). Thereafter, the ECU 30 increases the engine speed to a predetermined level while maintaining the output torque. When the engine speed reaches a predetermined level, the output torque is increased by control of the engine 3 and the second motor / generator 5 at time t1c. Thereby, the output torque reaches the target value that satisfies the acceleration request at time t2c. The control of this embodiment can raise the output torque earlier than increasing the output torque after waiting for the engine speed to rise as in the comparative example. Therefore, there is no non-reaction period in which the output torque does not increase and becomes steady. Thereby, even in a situation where the motor torque is limited, it is possible to suppress deterioration in drivability at the time of requesting acceleration.

  Next, an example of a control routine performed by the ECU 30 will be described with reference to FIG. The program of the control routine in FIG. In addition, each time of FIG. 3 is added to the corresponding location of each step of FIG. The control routine of FIG. 4 is repeatedly executed at predetermined intervals in the non-differential operation mode and in the partial cylinder operation, that is, in the mode (4). In step S <b> 1, the ECU 30 acquires operation information of the accelerator pedal 31 based on a signal from the accelerator opening sensor 32. The depression amount and depression speed of the accelerator pedal 31 are acquired as operation information. In step S2, the ECU 30 determines whether there is an acceleration request exceeding a predetermined reference. This determination is performed based on whether or not the operation information acquired in step S1 exceeds a threshold value set for each of the predetermined depression amount and depression speed of the accelerator pedal 31. If there is an acceleration request exceeding a predetermined standard, the process proceeds to step S3. When there is no such acceleration request, the subsequent processing is skipped and the current routine is terminated.

  In step S <b> 3, the ECU 30 determines whether the motor torque output from the first motor / generator 4 or the second motor / generator 5 is limited based on the output limit of the battery 16. If the motor torque is limited, the process proceeds to step S4. If the motor torque is not limited, the process proceeds to step S8.

  In step S4, the ECU 30 performs all cylinder operation switching control for switching the operation mode of the engine 3 from partial cylinder operation to all cylinder operation. In step S5, the ECU 30 increases the engine torque. In step S6, the ECU 30 determines whether or not the engine torque or the output torque is equal to or greater than a predetermined value, and continues to increase the engine torque until the engine torque or the output torque exceeds a predetermined value. In step S7, the ECU 30 performs differential state switching control for switching the state of the power split mechanism 6 from the non-differential state to the differential state.

  On the other hand, if the motor torque is not limited, in step S8, the ECU 30 performs all-cylinder operation switching control and differential state switching control simultaneously. As a result, the completion of both controls is accelerated, and the rise of the output torque is faster than when the outputs are not simultaneously executed. Note that “simultaneous” includes not only the case where the execution periods of these controls coincide, but also the case where the execution periods of each control partially overlap. Moreover, in the process of step S8, instead of performing each control simultaneously, the start timing of each control may be moved back and forth, and the other control may be started after one control is completed.

  In step S9, the ECU 30 increases the engine speed. In step S10, the ECU 30 determines whether or not the engine speed is equal to or higher than a predetermined value, and continues to increase the engine speed until the engine speed becomes equal to or higher than the predetermined value. In step S11, the ECU 30 keeps the engine speed constant and increases the output torque to the target value.

  The ECU 30 thus executes the control routine of FIG. 4 so that the ECU 30 functions as a mode control switching unit according to the present invention. As described above, even when the motor torque is limited, the driver at the time of an acceleration request It is possible to suppress the deterioration of the ability.

  This invention is not limited to the said form, It can implement with a various form within the range of the summary of this invention. In the above embodiment, the first motor / generator 4 is locked by the motor lock mechanism 25 to switch the power split mechanism 6 as the differential mechanism from the differential state to the non-differential state. However, the locking means for switching the differential mechanism from the differential state to the non-differential state is not limited to the case of preventing the rotation of the first motor / generator itself. For example, the power transmission path from the differential mechanism to the first motor / generator is separated by a clutch, and the locking mechanism is implemented in such a manner that the elements on the differential mechanism side are fixed, and the differential mechanism is in a differential state by the locking mechanism. It is also possible to switch from a non-differential state.

1 vehicle 3 engine 4 first motor / generator 5 second motor / generator 6 power split mechanism (differential mechanism)
16 Battery 20 Output gear train (output unit)
25 Motor lock mechanism (locking means)
30 ECU (mode switching control means)

Claims (2)

It has a plurality of cylinders, and can perform partial cylinder operation in which some cylinders of the plurality of cylinders are deactivated and the remaining cylinders are operated, and all cylinder operation in which all cylinders of the plurality of cylinders are operated. Engine,
A first motor generator;
An output for transmitting torque to the drive wheels;
A differential mechanism that distributes the torque of the engine to the first motor / generator and the output unit;
A second motor / generator connected to the output unit;
A battery capable of supplying power to the first motor generator and the second motor generator;
Lock means capable of switching between a differential state in which the torque of the engine is distributed to the first motor / generator and the output unit and a non-differential state in which the distribution is stopped;
Applied to hybrid vehicles with
In the hybrid vehicle control device for limiting the motor torque output from the first motor / generator or the second motor / generator based on the output limit of the battery,
When the engine operation mode is the partial cylinder operation and the differential mechanism is in the non-differential state, when an acceleration request exceeding a predetermined reference is received, the engine operation mode is changed to the engine operation mode. Performing the all cylinder operation switching control for switching from the partial cylinder operation to the all cylinder operation, and the differential state switching control for switching the state of the differential mechanism from the non-differential state to the differential state, and the output unit Comprising mode switching control means for increasing the output torque output from
When the motor torque is not limited by the motor torque limiting unit, the mode switching control unit performs the differential state switching control and the all-cylinder operation switching control so that the engine speed increases. When the output torque is increased after controlling the motor / generator and the motor torque is limited by the motor torque limiting means, the differential mechanism is in the non-differential state after the all-cylinder operation switching control is performed. The control apparatus for a hybrid vehicle, wherein the output torque is increased while the differential state switching control is performed thereafter to increase the output torque.   The mode switching control means performs the differential state switching control and the all cylinder operation switching control simultaneously when the motor torque is not limited by the motor torque limiting means, 2. The control device according to claim 1, wherein the output torque is increased after performing cylinder operation switching control and controlling the first motor / generator so that the engine speed increases.

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