JP5821475B2 - Control device for hybrid vehicle - Google Patents

Description

  The present invention relates to a control device for a hybrid vehicle that generates electric power from an electric motor with surplus torque of an engine output torque, and more particularly to an improvement for suppressing a decrease in drivability while improving fuel efficiency.

  A hybrid vehicle including an engine that is a main drive source and an electric motor that functions as a drive source is known. For example, an engine, an electric motor connected to a power transmission path between the engine and driving wheels, a transmission provided in a power transmission path between the engine and driving wheels, the engine and the transmission thereof That is, a hybrid vehicle including a torque converter provided in a power transmission path between the input member and the lockup clutch provided between an input member and an output member in the torque converter. In such a hybrid vehicle, there has been proposed a technique for improving fuel efficiency by generating electric power from an electric motor with surplus torque of engine output torque. For example, this is the drive control device for a hybrid vehicle described in Patent Document 1. According to this technology, the electric power is generated by the surplus torque with respect to the required torque (required driving force) in the engine output, and the driving pattern that minimizes the fuel consumption equivalent amount is determined, so that the vehicle is always operated with the best fuel consumption. It can be driven.

JP 2007-269257 A JP 2005-039884 A

  By the way, generally, when the engine output torque is greatly increased, an error between the required torque (target torque) and the actual torque increases. However, in the prior art, since such an error is not taken into account regarding the setting of the engine operating point and the electric power generation amount in the control for generating electric power with the surplus torque of the engine output torque, the driving state of the vehicle In some cases, this error affects the acceleration, which may cause the driver to feel uncomfortable. That is, drivability may be reduced when the electric motor generates power with the surplus torque of the engine output torque. Such a problem has been newly found in the process in which the present inventors and others are diligently researching with the aim of improving drivability and fuel consumption in a hybrid vehicle.

  The present invention has been made against the background of the above circumstances, and the object of the present invention is to reduce drivability while improving fuel efficiency when generating electric power with a surplus torque of engine output torque. It is providing the control apparatus of the hybrid vehicle which suppresses.

To achieve such objectives, it is an the onset Ming gist, engine and, and connected to an electric motor in a power transmission path between the engine and the drive wheels, between the engine and the drive wheels A transmission provided in a power transmission path, a torque converter provided in a power transmission path between the engine and the drive wheel, and a lockup clutch provided between an input member and an output member in the torque converter; In the control of the hybrid vehicle equipped with the above, in the control for charging by the electric motor using the surplus torque of the engine output torque with respect to the required torque, the larger the gear ratio of the transmission, the more the restriction of the charging amount by the electric motor state value is a small value, in and a state where the lock-up clutch is released, that the lock-up clutch is engaged It is characterized in that the charge amount limit by remote said electric motor is a small value.

In this way, in the control of charging by the electric motor using the surplus torque of the engine output torque with respect to the required torque, the limit value of the charging amount by the electric motor is set to a smaller value as the speed ratio of the transmission is larger , In addition, when the lockup clutch is released, the limit value for the amount of charge by the electric motor is smaller than when the lockup clutch is engaged . In a driving state in which an error is likely to affect acceleration and the transmission gear ratio is relatively large, the limit value of the charging amount can be reduced to suppress the occurrence of discomfort, and in a driving state in which the gear ratio is relatively small. Maximum fuel economy can be improved. The error between the required torque and the engine output torque is likely to affect the acceleration. In the drive state in which the lockup clutch is released, the limit value of the charge amount can be reduced to suppress the occurrence of a sense of incongruity, and the lockup clutch In the drive state in which is engaged, the maximum fuel consumption can be improved. That is, it is possible to provide a control device for a hybrid vehicle that suppresses a decrease in drivability while improving fuel efficiency when generating electric power with the surplus torque of the engine output torque.

It is a figure which shows notionally the structure of the drive system which concerns on the hybrid vehicle to which this invention is applied suitably. It is a functional block diagram explaining the principal part of the control function with which the electronic control apparatus of the hybrid vehicle of FIG. 1 was equipped. FIG. 2 is a diagram showing an example of a shift diagram used for shift control of an automatic transmission in the hybrid vehicle of FIG. 1. FIG. 2 is a diagram showing an example of a lockup diagram used for engagement control of a lockup clutch in the hybrid vehicle of FIG. 1. FIG. 2 is a diagram schematically illustrating control for charging by an electric motor using surplus torque of engine output torque in the hybrid vehicle of FIG. 1. FIG. 2 is a diagram showing an example of a fuel consumption map that is experimentally obtained and stored in advance for the engine in the hybrid vehicle of FIG. 1. It is a figure explaining the error of the target engine torque and the actual engine torque in a general engine. It is a figure which shows an example of the charge amount limit value setting map used for the setting of the charge amount limit value in the hybrid vehicle of FIG. It is a figure which shows another example of the charge amount limit value setting map used for the setting of the charge amount limit value in the hybrid vehicle of FIG. It is a figure which shows an example of the relationship for selecting the charge amount limit value setting map used for the setting of the charge amount limit value in the hybrid vehicle of FIG. It is a time chart explaining the charge amount limit value setting control of the present Example by the electronic controller in the hybrid vehicle of FIG. It is a flowchart explaining the principal part of the charge amount limit value setting control of the present Example by the electronic controller in the hybrid vehicle of FIG.

  The present invention is suitably applied to a hybrid vehicle including a clutch that intermittently connects a power transmission path between an engine and an electric motor according to an engaged state. Preferably, the present invention is preferably applied to control in which electric power is generated by the surplus torque of the engine output torque in the travel mode in which the engine is driven in a state where the clutch is engaged. In other words, the control of the present invention is not performed when the clutch is released, and the torque control of the motor is performed exclusively in the travel mode using the motor as a drive source.

  The clutch is preferably a hydraulic friction engagement device whose engagement state is controlled by hydraulic pressure, but an electromagnetic clutch or a magnetic powder clutch whose electromagnetic engagement state is controlled can be used. Good. The present invention is also suitable for a hybrid vehicle in which a plurality of clutches are provided in a power transmission path between the engine and the drive wheels, and the power transmission in the power transmission path is controlled according to the engagement state of each clutch. Applies to

  The transmission is preferably a stepped automatic transmission including a plurality of hydraulic friction engagement devices, but includes a CVT such as a belt-type continuously variable transmission or a toroidal continuously variable transmission. The present invention is also suitably applied to a hybrid vehicle. The present invention may be applied to a hybrid vehicle in which a plurality of electric motors function as electric continuously variable transmissions by electric paths between the plurality of electric motors. As the transmission, a gear-type transmission having a plurality of gear pairs with different gear ratios and a synchromesh mechanism, or a so-called semi-transmission that automatically shifts the gear-type transmission without depressing the clutch pedal. The present invention may be applied to a hybrid vehicle equipped with an automatic transmission.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a diagram conceptually illustrating a configuration of a drive system according to a hybrid vehicle 10 to which the present invention is preferably applied. The hybrid vehicle 10 shown in FIG. 1 includes an engine 12 and an electric motor MG that function as a driving source, and the driving force generated by the engine 12 and the electric motor MG includes a torque converter 16, an automatic transmission 18, and a difference. It is configured to be transmitted to a pair of left and right drive wheels 24 via a moving gear device 20 and a pair of left and right axles 22, respectively. With this configuration, the hybrid vehicle 10 is driven using at least one of the engine 12 and the electric motor MG as a driving source for traveling. That is, in the hybrid vehicle 10, the engine traveling mode exclusively using the engine 12 as a driving source for traveling, the EV traveling (motor traveling) mode exclusively using the electric motor MG as a driving source for traveling, and the engine 12 and Any of the hybrid travel modes using the electric motor MG as a travel drive source is selectively established.

  The engine 12 is, for example, an internal combustion engine such as a direct injection gasoline engine or a diesel engine in which fuel is directly injected into a combustion chamber. In order to control the drive (output torque) of the engine 12, an output control device 14 including a throttle actuator that controls opening and closing of an electronic throttle valve, a fuel injection device that performs fuel injection control, an ignition device that performs ignition timing control, and the like. Is provided. The output control device 14 controls the opening and closing of the electronic throttle valve by the throttle actuator for throttle control in accordance with a command supplied from an electronic control device 60 to be described later, as well as the fuel from the fuel injection device for fuel injection control. The engine 12 is controlled for output by controlling injection and controlling the ignition timing by the ignition device for ignition timing control.

  The electric motor MG is a motor generator having a function as a motor (motor) that generates a driving force and a generator (generator) that generates a reaction force, and a power transmission path between the engine 12 and the electric motor MG. Is provided with a clutch K0 for controlling power transmission in the power transmission path in accordance with the engaged state. That is, the crankshaft 26 that is an output member of the engine 12 is selectively connected to the rotor 30 of the electric motor MG through the clutch K0. The rotor 30 of the electric motor MG is connected to a front cover which is an input member of the torque converter 16. The stator 32 of the electric motor MG is fixed to a housing 28 that is a non-rotating member.

  The clutch K0 is, for example, a multi-plate hydraulic friction engagement device whose engagement is controlled by a hydraulic actuator, and its engagement state is engaged (completely engaged) according to the hydraulic pressure supplied from the hydraulic control circuit 50. ), Slip engagement, or release (fully open). When the clutch K0 is engaged, power transmission in the power transmission path between the crankshaft 26 and the torque converter 16 is performed (connected), while the clutch K0 is released, thereby Power transmission in the power transmission path between the crankshaft 26 and the torque converter 16 is interrupted. When the clutch K0 is slip-engaged, power transmission according to the transmission torque of the clutch K0 is performed in the power transmission path between the crankshaft 26 and the torque converter 16.

  The automatic transmission 18 is, for example, a stepped automatic transmission mechanism in which any one of a plurality of predetermined shift speeds (speed ratios) is selectively established. An engagement element is provided. For example, a plurality of hydraulic friction engagement devices, such as multi-plate clutches and brakes, that are engaged and controlled by hydraulic actuators, are provided, and the plurality of hydraulic friction devices according to the hydraulic pressure supplied from the hydraulic control circuit 50 are provided. By selectively engaging or disengaging the engagement devices, a plurality of (for example, first to sixth speeds) having different transmission gear ratios γ according to combinations of the coupling states of the hydraulic friction engagement devices. Either a forward gear (forward gear, forward travel gear) or a reverse gear (reverse gear, reverse travel gear) is selectively established.

  The torque converter 16 is a lock that is directly connected between a pump impeller 16p as an input member and a turbine impeller 16t as an output member so that the pump impeller 16p and the turbine impeller 16t are rotated together. An up clutch (direct clutch) LU is provided. The lockup clutch LU is controlled to be engaged (completely engaged), slip engaged, or released (completely released) in accordance with the hydraulic pressure supplied from the hydraulic control circuit 50. It has become. The pump impeller 16p is connected to the rotor 30 of the electric motor MG and is connected to the crankshaft 26 of the engine 12 via the clutch K0. The turbine impeller 16t is connected to the input shaft of the automatic transmission 18.

  The electric motor MG is connected to a power storage device 58 such as a battery or a capacitor via an inverter 56, and is supplied to a coil provided in the electric motor MG by controlling the inverter 56 by an electronic control device 60 described later. By adjusting the drive current, the drive of the electric motor MG is controlled. In other words, the output torque of the electric motor MG can be increased or decreased by controlling the inverter 56 by the electronic control unit 60. The output torque from the electric motor MG is output only to the torque converter 16 when the clutch K0 is disengaged (not engaged), but a part of the output torque is applied when the clutch K0 is engaged. Is output to the torque converter 16 and the other part is output to the engine 12.

In the hybrid vehicle 10, for example, when shifting from the EV travel mode using the electric motor MG as a drive source for travel to the engine travel mode using the engine 12 as a drive source or the hybrid travel mode, the clutch K 0 is engaged. Thus, the engine 12 is started. That is, when the clutch K0 is slip-engaged or completely engaged, the engine 12 is rotationally driven by the torque for starting the engine transmitted through the clutch K0, whereby the engine rotational speed _NE is increased. The engine 12 is started (pushed) by controlling engine ignition, fuel supply, and the like while being pulled up. At this time, compensation torque is generated by the electric motor MG, and generation of acceleration (deceleration G) in the vehicle longitudinal direction is suppressed. That is, the starting of the engine 12 is preferably performed by the torque obtained from the explosion energy by ignition and the torque obtained from the engagement energy by the clutch K0, that is, the engine starting torque transmitted through the clutch K0. This is done by rotating the engine 12.

  The hybrid vehicle 10 includes a control system as illustrated in FIG. The electronic control device 60 shown in FIG. 1 includes a so-called microcomputer having a CPU, a RAM, a ROM, an input / output interface, and the like, and the CPU uses a temporary storage function of the RAM in advance in the ROM. By performing signal processing according to the stored program, the drive control of the engine 12, the drive control of the electric motor MG, the shift control of the automatic transmission 18, the engagement force control of the clutch K0, and the lock-up clutch LU In addition to basic control such as engagement control, various controls such as charge amount limit value setting control according to the present embodiment described later are executed.

As shown in FIG. 1, the electronic control device 60 is supplied with various input signals detected by each sensor provided in the hybrid vehicle 10. For example, a signal indicating the accelerator opening degree A _CC detected by the accelerator opening degree sensor 62 corresponding to the depression amount of an accelerator pedal (not shown), the rotation speed of the engine 12 (engine speed) detected by the engine speed sensor 64 ) signal representing the N _E, a turbine rotational speed of the turbine impeller 16t of the rotational speed sensor 66 the torque converter 16 detected by the (signal representative of the turbine speed) N _T, the electric motor detected by the motor rotation speed sensor 68 MG rotational speed signal representing a (motor rotation speed) N _MG, the signal representing the temperature T _MG of the motor MG detected by the motor temperature sensor 70 (or power storage device 58), the vehicle speed V detected by the vehicle speed sensor 72 signals representative signal representing the cooling water temperature T _W of the engine 12 detected by the water temperature sensor 74, the slope Inclination angle theta _ROAD to signals representing the gradient φ of the road surface of the road surface of the vehicle detected by the capacitors 76, and the power storage amount (remaining capacity, charge amount) of the electric storage device 58 detected by the SOC sensor 78 signals representative of the SOC Are input to the electronic control unit 60.

  Various output signals are supplied from the electronic control device 60 to each device provided in the hybrid vehicle 10. For example, a signal supplied to the output control device 14 of the engine 12 for drive control of the engine 12, a signal supplied to the inverter 56 for drive control of the electric motor MG, a shift of the automatic transmission 18 A signal supplied to a plurality of electromagnetic control valves in the hydraulic control circuit 50 for control, a signal supplied to a linear solenoid valve in the hydraulic control circuit 50 for engagement control of the clutch K0, the lock-up clutch A signal supplied to the linear solenoid valve in the hydraulic control circuit 50 for LU engagement control, a signal supplied to the linear solenoid valve in the hydraulic control circuit 50 for line pressure control, etc. It is supplied from the device 60 to each part.

  FIG. 2 is a functional block diagram for explaining a main part of the control function provided in the electronic control device 60. The hybrid drive control unit 80 shown in FIG. 2 executes hybrid drive control in the hybrid vehicle 10. That is, as shown in FIG. 2, the drive of the engine 12 is controlled via the output control device 14, and the drive of the electric motor MG is controlled via the inverter 56. An electric motor drive control unit 84 is provided, and drive control of the hybrid vehicle 10 is performed by the engine 12 and the electric motor MG through the engine drive control unit 82 and the electric motor drive control unit 84. For example, the engine 12 is stopped and the EV traveling mode is exclusively used with the electric motor MG as a driving source for traveling, the engine traveling mode is exclusively performed with the engine 12 as a driving source for traveling, and the engine 12 and the electric motor MG are both traveled. And various driving modes such as a hybrid driving mode in which regeneration (power generation) is performed by the electric motor MG according to the driving state is selectively selected according to the driving state of the hybrid vehicle 10 (vehicle driving state). Established.

  The K0 clutch engagement control unit 86 performs engagement control of the clutch K0. Specifically, the clutch is controlled by controlling the output pressure of an electromagnetic control valve (for example, a linear solenoid valve) provided in the hydraulic control circuit 50 to regulate the hydraulic pressure corresponding to the engagement pressure of the clutch K0. The engagement state of K0 is switched between engagement (complete engagement) and release (complete release). If necessary, the engagement pressure is controlled so that the clutch K0 is slip-engaged. The K0 clutch engagement control unit 86 is, for example, when a drive state in which the hybrid drive control unit 80 drives the engine 12 is established (for example, when switching from the EV travel mode to the hybrid travel mode or the engine travel mode). When the driving state in which the clutch K0 is engaged and the engine 12 is stopped by the hybrid drive control unit 80 is established (for example, when switching from the hybrid travel mode to the engine travel mode to the EV travel mode) ), The clutch K0 is released.

The shift control unit 88 executes shift control of the automatic transmission 18 based on the state of the hybrid vehicle 10 based on a predetermined relationship. For example, from the predetermined shift map as shown in FIG. 3, the automatic shift based on the accelerator opening degree A _CC detected by the accelerator opening degree sensor 62, the vehicle speed V detected by the vehicle speed sensor 72, and the like. The gear stage to be established in the machine 18 is determined, and the hydraulic pressure supplied to the automatic transmission 18 is controlled so that the gear stage is established. Specifically, an electromagnetic control valve (for example, a linear solenoid valve) of the hydraulic control circuit 50 that regulates the hydraulic pressure corresponding to the engagement pressure of each hydraulic friction engagement device in the automatic transmission 18 is provided. By controlling the output pressure, the engagement or release of each hydraulic friction engagement device is switched.

The LU clutch engagement control unit 90 controls the engagement state of the lockup clutch LU provided in the torque converter 16. For example, from the predetermined lock-up diagram as shown in FIG. 4, the opening degree θ _TH of the electronic throttle valve in the output control device 14 (corresponding to the accelerator opening degree A _CC detected by the accelerator opening degree sensor 62) Based on the vehicle speed V detected by the vehicle speed sensor 72, the lockup clutch LU is engaged (completely engaged), released (completely released), or slip-engaged in a certain region. Specifically, by controlling the output pressure of an electromagnetic control valve (for example, a linear solenoid valve) provided in the hydraulic control circuit 50 for regulating the hydraulic pressure corresponding to the engagement pressure of the lockup clutch LU, The engagement state of the lockup clutch LU is controlled. The slip region of FIG. 4 does not necessarily have to be provided, and the LU clutch engagement control unit 90 may control the engagement state of the lockup clutch LU between engagement and release.

The hybrid drive control unit 80 performs drive control of the hybrid vehicle 10 exclusively using the electric motor MG as a travel drive source in the EV travel mode. That is, the required output shaft torque is determined based on the accelerator opening degree A _cc and the vehicle speed V as the driver's required output amount from the driving force map stored in advance, and the required charging shaft value is considered from the required output shaft torque. Thus, the required driving force (required torque) is calculated. Then, the driving (output torque) of the electric motor MG is controlled so that the required driving force can be obtained. In this EV travel mode, the drive of the engine 12 is stopped and the clutch K0 is released (completely released). As a result, the power transmission path between the engine 12 and the electric motor MG is cut off, and no power is transmitted from the engine 12 to the lockup clutch 16 side. Conversely, from the lockup clutch 16 side to the engine 12. Torque transmission is not performed. In this EV travel mode, regeneration of the electric motor MG is performed when a predetermined condition is satisfied, such as when the vehicle is decelerated, and the generated electric energy is stored in the power storage device 58.

The hybrid drive control unit 80 performs drive control of the hybrid vehicle 10 exclusively using the engine 12 as a drive source for travel in the engine travel mode. That is, the target engine output is calculated so as to obtain the required torque obtained as described above, and as shown in FIG. 6 that is experimentally obtained and stored in advance so as to achieve both drivability and fuel efficiency. From the relationship (fuel consumption map), the operating point of the engine 12 is determined so that the fuel efficiency becomes as high as possible, and the engine 12 is set to the engine speed _NE and engine torque corresponding to the operating point. Control the drive. In this engine running mode, the clutch K0 is engaged (completely engaged). The electric motor MG is idled, but may be operated so as to perform regeneration according to the traveling state.

The hybrid drive control unit 80 performs drive control of the hybrid vehicle 10 using both the engine 12 and the electric motor MG as drive sources for traveling in the hybrid travel mode. That is, basically, the target engine output is calculated in consideration of transmission loss, auxiliary machine load, assist torque of the electric motor MG, etc. so as to obtain the required torque obtained as described above, and the drivability and fuel efficiency are calculated. The operating point of the engine 12 is determined so that the fuel efficiency becomes as high as possible from the relationship shown in FIG. The driving of the engine 12 is controlled so that the engine rotational speed _NE and the engine torque corresponding to the point are obtained, and the driving of the electric motor MG is controlled. In this hybrid travel mode, the clutch K0 is engaged (completely engaged).

The hybrid drive control unit 80 controls regeneration (power generation) by the electric motor MG. That is, when the execution of regeneration is determined based on the accelerator opening degree A _cc as the driver's output request amount from a predetermined relationship, the operation is controlled so that regeneration is performed by the electric motor MG. To do. The electric energy generated by the regeneration of the electric motor MG in this way is stored in the power storage device 58 via the inverter 56. When the electric motor MG is used as a driving source, electric energy is supplied from the power storage device 58 to the electric motor MG via the inverter 56 to generate a driving force.

The hybrid drive control unit 80 uses the surplus torque of the engine output torque with respect to the required torque obtained as described above in the travel mode in which the clutch K0 is engaged and the engine 12 is driven. Charge the battery. FIG. 5 is a diagram schematically illustrating the control for charging by the electric motor MG using the surplus torque of the engine output torque with respect to the required torque. As shown in FIG. 5, the hybrid drive control unit 80 causes the engine 12 to output an engine output torque N _E that is larger than the required torque, and a charge negative torque N that is a part of the engine output torque N _E. Electric power is generated by the electric motor MG using _G , and drive control of the engine 12 and regenerative control of the electric motor MG are performed so that the required torque is realized by the remaining torque. For example, the case where not think torque amplification by the torque converter 16, in such a control, part of the engine output torque N _E is used as a charging component negative torque N _G according to the power generation of the motor MG, residual torque N _E -N _G is transmitted to the differential gear unit 20 such as the output shaft torque. Here, by controlling so N _E -N _G becomes a value corresponding to the required torque, it is possible to set the operating point of the engine 12 while maintaining the driving force corresponding to the required torque.

As described above, the engine 12 has an operating point with good fuel efficiency. That is, in the relationship shown in FIG. 6 that is experimentally obtained and stored in advance so as to achieve both drivability and fuel efficiency, there is an operating point with relatively high fuel efficiency, while the fuel efficiency is relatively high. There is also a low operating point. For this reason, there is a case where fuel efficiency is improved when the engine output torque larger than the required torque is output by the engine 12. As described above with reference to FIG. to output the output torque N _E, performs power generation by the motor MG using the charging amount negative torque N _G is a part of the engine output torque N _E, realizing the required torque by residual torque N _E -N _G By doing so, fuel consumption can be improved while maintaining the required driving force.

  FIG. 7 is a diagram for explaining an error between the target engine torque and the actual engine torque. The relationship (target engine torque line) corresponding to the target value of the engine torque is a solid line, and the torque increasing direction from the target value of the engine torque. The upper limit value of the deviation in the direction is indicated by a one-dot chain line, and the upper limit value of the deviation in the torque decreasing direction is indicated by a two-dot chain line. As shown in FIG. 7, generally, as the engine output torque increases, the error between the target engine torque and the actual engine torque increases. This error occurs when the gear ratio γ is relatively large (when the gear ratio is low and low) compared to when the gear ratio γ of the automatic transmission 18 is relatively small (when the gear is high speed and high speed). It tends to appear as an effect on the vehicle acceleration (front-rear G), and the driver may feel uncomfortable due to such an error. The torque converter 16 has a torque amplifying function while the lockup clutch LU is released (including during slip engagement), but also amplifies the error between the target engine torque and the actual engine torque described above. That is, the error tends to appear as an effect on the vehicle acceleration (front-rear G) during release compared to when the lock-up clutch LU is engaged in the torque converter 16. There is a risk of discomfort.

  In order to improve the fuel efficiency while suppressing the driver's uncomfortable feeling caused by the error between the target value of the engine torque and the actual output value, the electronic control unit 60 of the present embodiment sets the charge amount limit value setting shown in FIG. A control unit 92 is provided. The charge amount limit value setting control unit 92 sets a limit value (upper limit value) of the charge amount of the power storage device 58. For example, in the control of charging by the electric motor MG using the surplus torque of the engine output torque with respect to the required torque by the hybrid drive control unit 80, the charge amount of the power storage device 58 is set according to the driving state of the hybrid vehicle 10. Set the limit value.

The charge amount limit value setting control unit 92 performs the charging by the electric motor MG using the surplus torque of the engine output torque with respect to the required torque by the hybrid drive control unit 80, and the gear ratio γ of the automatic transmission 18 The larger the is, the smaller the limit value of the charge amount by the electric motor MG is set. Preferably, in the multi-stage automatic transmission 18, the accelerator opening A detected by the accelerator opening sensor 62 from a predetermined relationship (charge amount limit value setting map) for each shift stage (gear stage). Based on _CC , a limit value for the amount of charge of power storage device 58 is set. FIG. 8 is a diagram showing an example of a charge amount limit value setting map used for setting such a charge amount limit value. The first speed stage “1st” and the third speed stage “3rd” in the automatic transmission 18 are shown. , And the relationship at the sixth speed “6th”. As shown in FIG. 8, each relationship is determined in advance such that the charge amount limit value increases as the accelerator opening degree A _CC increases. The relationship at the third speed has a larger charge amount limit value corresponding to the accelerator opening degree A _CC than the relationship at the first speed, and the relationship at the sixth speed is the same as that at the third speed. The charge amount limit value corresponding to the opening degree A _cc is large, and the charge amount limit value is set to be smaller at a lower speed stage (so that the charge amount limit value is increased at a higher speed stage). Therefore, preferably, the charge amount limit value setting unit 92 of the power storage device 58 is set such that the limit value of the charge amount becomes smaller for each shift stage (gear stage) in the automatic transmission 18 at a lower speed stage. Set the limit value of charge.

The charge amount limit value setting control unit 92 is controlled by the hybrid drive control unit 80 to perform charging by the electric motor MG using the surplus torque of the engine output torque with respect to the required torque. In the state in which is released, the limit value of the charge amount by the electric motor MG is set to a smaller value than in the state in which the lockup clutch LU is engaged. Preferably, the accelerator opening sensor 62 detects the relationship between the state in which the lock-up clutch LU of the torque converter 16 is disengaged and the state in which it is engaged (charge amount limit value setting map). A limit value for the amount of charge of the power storage device 58 is set based on the accelerator opening degree A _CC . FIG. 9 is a diagram showing an example of a charge amount limit value setting map used for setting such a charge amount limit value. The relationship corresponding to the state in which the lockup clutch LU is engaged is shown by a solid line. The relations corresponding to the states are indicated by broken lines. As shown in FIG. 9, each relationship is determined in advance such that the charge amount limit value increases as the accelerator opening degree A _CC increases. The relationship corresponding to the state in which the lockup clutch LU is engaged is such that the charge amount limit value corresponding to the same accelerator opening degree A _CC is larger than the relationship corresponding to the released state. In FIG. 9, the relationship corresponding to the state in which the lock-up clutch LU is slip-engaged is not defined, but preferably the relationship corresponding to the state in which the lock-up clutch LU is released is used. Alternatively, a relationship corresponding to the state in which the lockup clutch LU is engaged may be used, and the state in which the lockup clutch LU is engaged if the transmission torque of the clutch K0 is equal to or greater than a predetermined threshold. If the relationship is less than the threshold, the control may be performed such that the relationship corresponding to the released state of the lockup clutch LU is used. Further, as a relationship corresponding to the state in which the lockup clutch LU is slip-engaged, a relationship different from the relationship shown by the solid line and the broken line in FIG. 9 is determined in advance, and the charge amount restriction is performed based on the relationship. A value may be set.

  Preferably, the charge amount limit value setting control unit 92 performs the charging by the electric motor MG using the surplus torque of the engine output torque with respect to the required torque by the hybrid drive control unit 80. The charge amount limit value by the electric motor MG is set according to the shift speed (speed ratio) of the motor and the engagement state of the lockup clutch LU in the torque converter 16. For example, as shown in FIG. 10, each relationship (charge amount limit value setting map) is determined in advance corresponding to the shift stage of the automatic transmission 18 and the engagement state of the lockup clutch LU in the torque converter 16. It has been. The relationship when map 1-A is the first speed “1st” and the lockup clutch LU is engaged, map 1-B is the first speed “1st” and the lockup clutch LU is released If the map 2-A is the second speed “2nd” and the lockup clutch LU is engaged, the map 2-B is the second speed “2nd” and the lockup clutch The relationship when the LU is open, the relationship when the map 3-A is the third gear “3rd” and the lockup clutch LU is engaged, and the map 3-B is the third gear “3rd” And corresponding to the relationship when the lock-up clutch LU is released, respectively. That is, the relationship between when the lock-up clutch LU is engaged or released is determined individually for each gear position of the automatic transmission 18. Also in such an aspect, each relationship is such that the charge amount limit value becomes smaller at lower speeds, and the charge amount limit value becomes smaller in the state where the lockup clutch LU is released than in the engaged state. It is predetermined.

FIG. 11 is a time chart for explaining the charge amount limit value setting control of the present embodiment by the electronic control unit 60. First, at time t1, an accelerator pedal (not shown) is depressed, and the accelerator opening degree A _CC starts increasing. Next, at time t2, the system shaft required torque starts increasing in accordance with the increase in the accelerator opening degree A _CC , and the control for increasing the engine torque and the actual system shaft torque is started. Here, the torque of the electric motor MG is decreased (negative torque is increased). That is, in the control in which part of the engine torque is used for charging as the negative torque, the negative torque for charging by the electric motor MG is increased, and the charge amount is increased accordingly. Next, at time t3, the system shaft torque reaches a value corresponding to the accelerator opening A _CC after the increase, and the increase in engine torque is stopped. At the same time, the amount of charge reaches the limit value (pre-shift limit value) of the power storage device 58, and the increase in negative torque of the electric motor MG is stopped. Next, at time t4, the upshift (shift from the low speed stage to the high speed stage) of the automatic transmission 18 is started, the engine torque starts to increase, and the negative torque of the electric motor MG starts to increase. The Here, the system shaft torque is maintained, and the increase in engine torque is used to increase the negative torque of electric motor MG. The amount of charge is increased as the negative torque of the electric motor MG increases. Next, at time t5, the charge amount reaches the charge request amount of the power storage device 58, and the negative torque increase of the electric motor MG is stopped. That is, the increase in engine torque is stopped, and the increase in negative torque of the electric motor MG due to the increase is stopped. Next, at time t6, the upshift of the automatic transmission 18 is terminated. At the end of the shift, the charge amount limit value of the power storage device 58 is set to a value larger than the value before the shift, but in the control shown in FIG. 11, the charge request amount has been reached at time t5. The negative torque of the electric motor MG is maintained at the value at the time t5 after the time t5.

  FIG. 12 is a flowchart for explaining a main part of the charge amount limit value setting control of the present embodiment by the electronic control unit 60, and is repeatedly executed at a predetermined cycle.

First, in step (hereinafter, step is omitted) S1, it is determined whether or not the clutch K0 is engaged. If the determination in S1 is negative, in S2, the torque control of the electric motor MG is performed during normal EV traveling, that is, in the traveling mode in which the electric motor MG is used as a driving source by releasing the clutch K0. Although this routine is terminated, if the determination in S1 is affirmative, it is determined in S3 whether or not the first speed "1st" is established in the automatic transmission 18. If the determination in S3 is negative, the processing from S7 is executed. If the determination in S3 is positive, in S4, the lockup clutch LU of the torque converter 16 is engaged. It is determined whether or not there is. If the determination in S4 is affirmative, a predetermined charge amount limit value setting map 1-A is selected in S5, and the power storage device is selected based on the accelerator opening degree A _{CC and the} like from the map 1-A. After the charge amount limit value of 58 is set, this routine is terminated. If the determination in S4 is negative, a predetermined charge amount limit value setting map 1-B is selected in S6. Then, after the charge amount limit value of the power storage device 58 is set from the map 1-B based on the accelerator opening degree A _{CC and the} like, this routine is terminated.

In S <b> 7, it is determined whether or not the second speed “2nd” is established in the automatic transmission 18. If the determination in S7 is negative, the processing from S11 is executed, but if the determination in S7 is positive, the lockup clutch LU of the torque converter 16 is engaged in S8. It is determined whether or not there is. If the determination in S8 is affirmative, a predetermined charge amount limit value setting map 2-A is selected in S9, and the power storage device is selected based on the accelerator opening degree A _{CC and the} like from the map 2-A. After the charge amount limit value of 58 is set, this routine is terminated. If the determination in S8 is negative, a predetermined charge amount limit value setting map 2-B is selected in S10. Then, after the charge amount limit value of the power storage device 58 is set based on the accelerator opening degree A _{CC and the} like from the map 2-B, this routine is terminated.

In S11, it is determined whether or not the third speed "3rd" is established in the automatic transmission 18. If the determination in S11 is negative, the engagement of the lock-up clutch LU is performed or released for each shift speed in the same manner as in S3 to S10, etc., for the high speed speed of the fourth speed "4th" or higher. Is selected, and the charge amount limit value is set based on the map. If the determination in S11 is affirmative, the lockup of the torque converter 16 is performed in S12. It is determined whether or not the clutch LU is engaged. If the determination in S12 is affirmative, a predetermined charge amount limit value setting map 3-A is selected in S13, and the power storage device is selected based on the accelerator opening degree A _{CC and the} like from the map 3-A. After the charge amount limit value of 58 is set, this routine is terminated. If the determination in S12 is negative, a predetermined charge amount limit value setting map 3-B is selected in S14. Then, after the charge amount limit value of the power storage device 58 is set from the map 3-B based on the accelerator opening degree A _{CC and the} like, this routine is terminated. In the above control, S3 to S14 correspond to the operation of the charge amount limit value setting control unit 92.

  Thus, according to the present embodiment, in the control for charging by the electric motor MG using the surplus torque of the engine output torque with respect to the required torque, the charging by the electric motor MG becomes larger as the gear ratio γ of the automatic transmission 18 becomes larger. Since the limit value of the amount is set to a small value, an error between the required torque and the engine output torque is likely to affect the acceleration. In a driving state where the gear ratio γ of the automatic transmission 18 is relatively large, the amount of charge is By reducing the limit value, the target engine torque is reduced, and as a result, the error between the target engine torque and the actual engine torque is reduced, so that the driver's uncomfortable feeling can be suppressed. In a driving state in which the gear ratio γ of the automatic transmission 18 is relatively small, the influence of the engine torque error on the vehicle acceleration is small. Therefore, the maximum fuel consumption can be improved by increasing the charge amount limit value. That is, it is possible to provide the electronic control device 60 of the hybrid vehicle 10 that suppresses a decrease in drivability while improving fuel efficiency when generating electric power from the motor MG with surplus torque of the engine output torque.

  According to this embodiment, in the control for charging by the electric motor MG using the surplus torque of the engine output torque with respect to the required torque, the lock-up clutch LU is engaged when the lock-up clutch LU is released. Since the limit value of the charge amount by the electric motor MG is smaller than that in the state where the lockup clutch LU is released, the error between the required torque and the engine output torque tends to affect the acceleration, and the drive with the lockup clutch LU opened In the state, the target engine torque is reduced by reducing the limit value of the charge amount. As a result, the error between the target engine torque and the actual engine torque is reduced, so that it is possible to suppress the driver from feeling uncomfortable. In the driving state in which the lock-up clutch LU is engaged, the influence of the engine torque error on the vehicle acceleration is small, so that the maximum fuel consumption can be improved by increasing the charge amount limit value. That is, it is possible to provide the electronic control device 60 of the hybrid vehicle 10 that suppresses a decrease in drivability while improving fuel efficiency when generating electric power from the motor MG with surplus torque of the engine output torque.

  The preferred embodiments of the present invention have been described in detail with reference to the drawings. However, the present invention is not limited to these embodiments, and various modifications can be made without departing from the spirit of the present invention. Is.

  10: Hybrid vehicle, 12: Engine, 16: Torque converter, 16p: Pump impeller (input member), 16t: Turbine impeller (output member), 18: Automatic transmission, 24: Drive wheel, 60: Electronic control unit , LU: lock-up clutch, MG: electric motor

Claims (1)

An engine, an electric motor connected to a power transmission path between the engine and the drive wheels, a transmission provided on a power transmission path between the engine and the drive wheels, and between the engine and the drive wheels A control device for a hybrid vehicle, comprising: a torque converter provided in the power transmission path of the motor; and a lock-up clutch provided between an input member and an output member of the torque converter ,
In the control for charging by the electric motor using the surplus torque of the engine output torque with respect to the required torque, the limit value of the charging amount by the electric motor is set to a smaller value as the transmission gear ratio of the transmission is larger , and the lockup clutch is In the released state, the limit value of the charge amount by the electric motor is set to a smaller value than the state in which the lock-up clutch is engaged .

Images