JP5807907B2 - Control device for hybrid vehicle - Google Patents

Description

  The present invention relates to a technical field of a control device for a hybrid vehicle that travels by transmitting power output from at least one of an engine and a motor to drive wheels via a transmission.

  In recent years, attention has been focused on a hybrid vehicle that travels using at least one of an internal combustion engine such as a gasoline engine or a diesel engine and a motor (electric motor) operable with electric power stored in a battery as a power source. The hybrid vehicle regeneratively drives a motor during deceleration to generate electric power, and the obtained electric power is charged in a battery and stored. Then, by driving the electric motor using the charged electric power, the fuel consumption of the internal combustion engine is reduced and the fuel efficiency is improved.

  In a general traveling vehicle including a hybrid vehicle, vehicle posture stabilization control may be performed in order to stabilize the vehicle posture during, for example, turning. The vehicle attitude stabilization control is also referred to as so-called skid prevention control, and is intended to stabilize the vehicle behavior by canceling the yaw moment acting on the vehicle based on the understeer state or oversteer state during turning.

  With the spread of hybrid vehicles in recent years, introduction of this type of vehicle attitude stabilization control has also been attempted in hybrid vehicles. However, since a hybrid vehicle has an engine and a motor as power sources, it is necessary to coordinately control the engine and the motor in order to perform vehicle attitude stability control, and the control is more complicated than that of a conventional vehicle. The problem is that it is easy to convert. In other words, in hybrid vehicles, it is necessary to coordinate the outputs of these engines and motors in response to the ever-changing vehicle behavior, which complicates the control logic and increases costs. ing.

  With respect to such a problem, in Patent Document 1, when performing vehicle posture stability control, the vehicle posture is controlled by controlling only the output from the engine by limiting the output torque of a motor with good controllability to zero. Simplify stable control. Thereby, even in a hybrid vehicle, it is possible to divert the control logic used in a normal vehicle having only an engine as a power source, and the introduction of vehicle attitude stabilization control is facilitated.

JP 2007-331540 A

  In addition to the above-described vehicle attitude stabilization control, when driving wheels fall into a slipping state during acceleration / deceleration, the driving wheels output a predetermined torque from the driving power source as the vehicle behavior stabilization control during driving. There is a slip ratio control that prevents vehicle lock and recovers vehicle behavior. When the slip ratio control is performed in a hybrid vehicle, it is preferable to control the output torque of a motor having excellent controllability among an engine and a motor that are power sources.

  However, the vehicle attitude stabilization control and the slip ratio control are sometimes used in combination to further stabilize the vehicle behavior. However, as in Patent Document 1, a motor is used to simplify the control logic of the vehicle attitude stability control. If the output torque from the motor is set to zero, a dilemma that the slip ratio control performed by the motor output torque control cannot be performed occurs. Therefore, if the conventional control logic is applied to the hybrid vehicle as it is to try to achieve both vehicle attitude stabilization control and slip ratio control, there is a problem that complicated control logic must be introduced.

  The present invention has been made in view of the above problems, and in a hybrid vehicle having an engine and a motor as a driving power source, by using a simple control logic to achieve both vehicle attitude stability control and slip ratio control. An object of the present invention is to provide a control device for a hybrid vehicle that can effectively stabilize vehicle behavior.

In order to solve the above problems, a hybrid vehicle control device according to the present invention is provided with a clutch between an engine and a motor, and travels by transmitting power generated at least one of the engine and the motor to driving wheels. A vehicle control device, wherein when it is determined that the vehicle attitude is in an unstable state, the maximum output torque of the motor is less than or equal to a preset first motor torque in order to stabilize the vehicle attitude. Vehicle posture stability control means for performing vehicle posture stability control for controlling only the output torque of the engine while limiting so as to be, and when the slip ratio of the drive wheels is equal to or higher than a predetermined value, Driving torque or regenerative torque is applied to the motor so that the slip ratio of the drive wheel becomes the target slip ratio, thereby suppressing the slip state of the drive wheel. A slip rate control means for performing a slip rate control that, when it is carried further the slip ratio control during the performance of the previous SL vehicle posture stability control, the slip ratio control means, the maximum output torque of said motor Motor torque control means for relaxing to a second motor torque set larger than the first motor torque .

  According to the present invention, by limiting the output torque of a motor with good controllability to the first motor torque or less during the operation of the vehicle attitude stability control, it becomes possible to perform vehicle attitude stability control mainly using an engine even in a hybrid vehicle. Further, it is possible to simplify the cooperative control of the engine and the motor, and to perform the vehicle posture stability control with a simple control logic. Only when the slip ratio of the drive wheel exceeds a predetermined value and the slip ratio control needs to be performed during the vehicle attitude stabilization control, the motor torque necessary for the slip ratio control can be output. Thus, by relaxing the restriction by the first motor torque to the second motor torque, the slip ratio control can be performed with a simple control logic even during the vehicle attitude stabilization control. As described above, according to the present invention, vehicle behavior can be effectively stabilized by making vehicle posture stabilization control and slip ratio control compatible by using a simple control logic.

  Preferably, the first motor torque is zero torque. According to this, when the vehicle attitude stabilization control is performed, the output torque from the motor is limited to zero, so that only the output from the engine is controlled, thereby further simplifying the vehicle attitude stability control. Can do. Accordingly, even in a hybrid vehicle, vehicle posture stability control can be easily performed by diverting the control logic used in a normal vehicle having only an engine as a power source.

  The second motor torque may be set larger than the first motor torque. According to this, while limiting the first motor torque during the operation of the vehicle attitude stability control, the influence of the output torque from the motor is eliminated, and the vehicle attitude stability control is simplified, while the slip ratio is reduced. By allowing the output of the second motor torque as much as necessary for the slip ratio control when the control needs to be performed, the slip ratio control is appropriately performed even during the vehicle attitude stabilization control. be able to.

  According to the present invention, by limiting the output torque of a motor with good controllability to the first motor torque or less during the operation of the vehicle attitude stability control, it becomes possible to perform vehicle attitude stability control mainly using an engine even in a hybrid vehicle. Further, it is possible to simplify the cooperative control of the engine and the motor, and to perform the vehicle posture stability control with a simple control logic. Only when the slip ratio of the drive wheel exceeds a predetermined value and the slip ratio control needs to be performed during the vehicle attitude stabilization control, the motor torque necessary for the slip ratio control can be output. Thus, by relaxing the restriction by the first motor torque to the second motor torque, the slip ratio control can be performed with a simple control logic even during the vehicle attitude stabilization control. As described above, according to the present invention, vehicle behavior can be effectively stabilized by making vehicle posture stabilization control and slip ratio control compatible by using a simple control logic.

1 is a block diagram conceptually showing an overall configuration of a hybrid vehicle according to an embodiment. It is a schematic diagram which shows operation | movement of the dual clutch transmission at the time of the speed change of the hybrid vehicle which concerns on a present Example. It is a flowchart figure which shows the motor torque control implemented with the hybrid vehicle which concerns on a present Example. It is a graph which shows transition of the slip ratio of a driving wheel and the output torque of a motor in slip ratio control.

  Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention unless otherwise specified, but are merely illustrative examples. Not too much.

  FIG. 1 is a block diagram conceptually showing the overall configuration of the hybrid vehicle 1 according to the present embodiment. The hybrid vehicle 1 is a hybrid electric vehicle having an engine 2 and a motor 3 as driving power sources. The power of the engine 2 and the motor 3 is transmitted to the propeller shaft 5 through the dual clutch transmission 4 at a predetermined gear ratio. The dual clutch transmission 4 has a plurality of clutches, and the power output from the engine 2, the motor 3, or both the engine 2 and the motor 3 is used as a power source by switching the connection state of these clutches. It is configured to transmit to the 5 side. The motive power transmitted to the propeller shaft 5 is driven by the drive wheels 8 via the differential 6 and the drive shaft 7 so that the hybrid vehicle 1 travels.

  The engine 2 is an internal combustion engine that functions as one of the power sources of the hybrid vehicle 1, and may be a gasoline engine or a diesel engine. In the case of a gasoline engine, a so-called direct injection type gasoline engine that directly injects fuel into the combustion chamber may be used.

  The motor 3 is an electric motor including a stator (stator) that generates a predetermined magnetic field and a rotor (rotor) that rotates across the magnetic field generated by the stator, and is incorporated in the dual clutch transmission 4. It is. The motor 3 is driven by power supplied from the battery 10 via the inverter 9 to generate a driving torque, and functions as one of the power sources of the hybrid electric vehicle 1. When the motor 3 is regeneratively driven, it generates electric power by generating regenerative energy and also functions as a regenerative brake by generating braking torque. The electric power generated by the motor 3 is DC converted by the inverter 9 and then charged to the battery 10.

  Here, the operation of the dual clutch transmission 4 will be specifically described with reference to FIG. FIG. 2 is a schematic diagram showing the operation of the dual clutch transmission 4 when the hybrid vehicle 1 according to this embodiment is shifted. 2 (a) and 2 (b), the power transmission path to the propeller shaft 5 is shown thick.

  The dual clutch transmission 4 has a first power transmission system 4a and a second power transmission system 4b as paths for transmitting power to the drive wheel 8 side. FIG. 2A illustrates a case where power is transmitted to the propeller shaft 5 via the first power transmission system 4a. The first power transmission system 4a is a power transmission system capable of transmitting the power of the engine 2 and the motor 3 to the drive wheels 8. The first power transmission system 4a includes a first clutch 11a provided between the engine 2 and the motor 3 and an even gear ( And a transmission gear group 12a in charge of 2nd speed, 4th speed, and 6th speed).

  On the other hand, FIG. 2B illustrates a case where power is transmitted to the propeller shaft 5 via the second power transmission system 4b. The second power transmission system 4b is a power transmission system capable of transmitting the power of the engine 2 to the drive wheels 8, and includes a second clutch 11b for switching the connection state between the engine 2 and the drive wheels 8 and an odd-numbered shift. And a transmission gear group 12b in charge of the stage (first speed, third speed, and fifth speed).

  As shown in FIG. 2A, when the power of the engine 2 and the motor 3 is transmitted to the drive wheel 8 side via the first power transmission system 4a, the first clutch 11a is in a connected state. In addition, the second clutch 11b is in a disconnected state. At this time, in the transmission gear group 12b of the second power transmission system 4b, a gear stage to be shifted at the next timing is selected (pre-shifted) in advance.

  Further, as shown in FIG. 2B, when the power of the engine 2 is transmitted to the drive wheel 8 side through the second power transmission system 4b, the second clutch 11b is in the connected state. The first clutch 11a is in a disconnected state. At this time, in the transmission gear group 12a of the first power transmission system 4a, a gear stage to be shifted at the next timing is selected (preshifted) in advance. Thereby, in the dual clutch transmission 4, the time required for the shift operation can be shortened, and energy loss such as torque loss can be reduced. As described above, the hybrid vehicle 1 switches either the first power transmission system 4a or the second power transmission system 4b by alternately switching the connection state of the first clutch 11a and the second clutch 11b to connection / disconnection. Travel through while selecting the appropriate gear.

  Returning again to FIG. 1, the battery 10 is a storage battery composed of secondary battery cells that store electric power for powering the motor 3. The battery 10 is charged with DC power in advance, and the DC power output at the time of discharging is AC converted by the inverter 9 and consumed for powering driving of the motor 3. On the other hand, when the motor 3 is regeneratively driven, AC power generated by the motor 3 is converted into DC by the inverter 9 and the battery 10 is charged.

  The upper limit charge amount and the lower limit charge amount of the battery 10 are defined in advance according to various conditions such as the type and number of secondary battery cells constituting the battery 10. The amount of charge of the battery is controlled by the electronic device so as to be within the range of the upper limit charge amount to the lower limit charge amount. By preventing the battery 10 from falling into an overcharge / overdischarge state, the life of the battery 10 can be extended. It is illustrated.

  Further, the hybrid vehicle 1 is provided with sensors for detecting parameters necessary for performing various controls by the ECU 14 described later. Specifically, although not shown in FIG. 1, a wheel speed sensor, a yaw rate sensor, a steering sensor, a lateral acceleration sensor, a vehicle speed sensor, and the like are provided. Particularly in this embodiment, the vehicle behavior is stabilized by vehicle attitude stabilization control and slip ratio control by comprehensively judging whether or not the vehicle behavior is disturbed based on the detection values from these sensors. Yes.

  The brake pedal 15 and the accelerator pedal 16 are used to control the power of the engine 2 and the motor 3 and the braking force of the motor 3 and the mechanical brake in accordance with the driver's intention by detecting the degree of depression.

  The ECU 14 performs the entire operation of the hybrid vehicle 1 based on detection values of various sensors provided in the hybrid vehicle 1 and information (depression amount) regarding acceleration / deceleration requests from the driver obtained from the brake pedal 15 and the accelerator pedal 16. An electronic control unit to control. Specifically, it is an electronic control unit comprising a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), etc., and various types described later according to a control program stored in the ROM. It is configured to be able to execute control. For example, the ECU 14 controls the torque to be output from the engine 2 based on the above various information, or controls the inverter 9 to power drive or regenerate the motor 3.

  Next, with reference to FIG. 3, the motor torque control performed in the hybrid vehicle 1 will be described. FIG. 3 is a flowchart illustrating motor torque control performed in the hybrid vehicle 1 according to the present embodiment. As will be described below, in the motor torque control, the ECU 14 functions as an example of the “motor torque control means” of the present invention.

  First, the ECU 14 determines whether or not vehicle posture stability control is being performed while the vehicle is traveling (step S101). The vehicle attitude stabilization control is intended to stabilize the vehicle behavior by canceling the yaw moment acting on the vehicle based on, for example, an understeer state or an oversteer state at the time of turning, and the wheel speed provided in the hybrid vehicle 1 This is performed based on parameters acquired from various sensors such as a sensor, a yaw rate sensor, a steering sensor, a lateral acceleration sensor, and a vehicle speed sensor. The detailed control content of the vehicle attitude stabilization control is well known and will not be described in detail here.

  When the vehicle attitude stabilization control is in operation (step S101: YES), the ECU 14 limits the output torque of the motor 3 to the first motor torque T1 (step S102). As described above, by limiting the output torque of the motor having good controllability to the first motor torque T1 or less during the operation of the vehicle posture stability control, the vehicle posture stability control can be performed mainly in the hybrid vehicle 1 using the engine 2 as a main component. This makes it possible to simplify the cooperative control with the motor 3 and avoid the complexity of the vehicle posture stability control.

  Particularly in the present embodiment, the first motor torque T1 is set to zero torque. According to this, when the vehicle attitude stabilization control is performed, the output torque from the motor 3 is limited to zero, so that only the output from the engine 2 is controlled, thereby further simplifying the vehicle attitude stability control. it can. Thereby, also in the hybrid vehicle 1, since the control logic used for the normal vehicle which has only the engine 2 as a power source can be diverted, vehicle attitude stability control can be implemented easily.

  When the vehicle posture stabilization control is not in operation (step S101: NO), the output torque of the motor 3 is controlled as usual according to the running state (step S105).

  Subsequently, the ECU 14 determines whether or not the slip ratio control is in operation during the operation of the vehicle attitude stabilization control (step S103). Here, FIG. 4 is a graph showing the transition of the slip ratio of the drive wheels 8 and the output torque of the motor 3 in the slip ratio control. The slip rate S shown in FIG. 4A uses a value obtained by converting the wheel speed detected by the wheel speed sensor installed in each drive wheel 8 by the ECU 14. The motor output torque (second motor torque T2) shown in FIG. 4B is an output value controlled by the ECU 14.

  First, when the hybrid vehicle 1 starts decelerating by releasing the accelerator pedal 16 from a state where the driver depresses the accelerator pedal 16 by a certain amount, the road surface approaches the low μ road at time t0, so that the slip ratio S Assuming that the situation has risen. When the slip ratio S increases from time t0 to time t1 and exceeds the predetermined threshold value S1 at time t1, slip ratio control is activated when the hybrid vehicle 1 falls into a slip state. At this time, since the drive wheels 8 of the hybrid vehicle 1 show a locking tendency, the ECU 14 switches the motor 3 to the power running driving or reduces the regenerative driving so as to alleviate the locking tendency. As a result, the slip ratio S decreases, and when it falls below the predetermined threshold value S1 at time t2, the drive control of the motor 3 is returned to the normal regenerative drive. Even after time t2, the slip rate S is greater than the predetermined threshold value S1 at times t3 to t4 and t5 to 6, so that the output torque of the motor 3 is controlled by the ECU 14 as described above. Thus, recovery of the vehicle behavior is achieved.

  When the slip ratio control is in operation during the operation of the vehicle attitude stabilization control (step S103: YES), the limit value of the output torque of the motor 3 set to the first motor torque T1 in step S102 is set as the slip ratio. In order to enable control, the second motor torque T2 shown in FIG. 4B is changed (step S104). Thus, only when the slip ratio control is in operation, the vehicle can be controlled by relaxing the restriction by the first motor torque T1 so that the second motor torque T2 necessary for the slip ratio control can be output. Slip rate control can be performed even when posture stabilization control is performed. As a result, the vehicle attitude stabilization control can be simplified, and can be implemented in combination with the slip ratio control, and the vehicle behavior can be stabilized effectively.

  The second motor torque T2 is set to be larger than the first motor torque T1 (set to zero in this embodiment). As a result, during the operation of the vehicle attitude stability control, by limiting to the first motor torque T1, the influence of the output torque from the motor 3 is eliminated and the vehicle attitude stability control is simplified, while the slip ratio is reduced. By permitting the output of the second motor torque T2 as much as necessary for the slip ratio control when the control is in operation, the slip ratio control is appropriately performed even during the operation of the vehicle attitude stabilization control. be able to. Therefore, the second motor torque T2 is the drive torque or regenerative torque that should be output from the motor 8 in order to recover the drive wheel 8 from the slip state by controlling the slip ratio of the drive wheel 8 to the target slip ratio. It should be set as.

  If the slip ratio control is not operating during the operation of the vehicle attitude stabilization control (step S103: NO), the motor 3 is set to the output torque limit value of the motor 3 set to the first motor torque T1 in step S102. The output torque is limited to end the control.

  As described above, according to the present invention, the engine 2 is controlled even in the hybrid vehicle 1 by limiting the output torque of the motor 3 having good controllability to the first motor torque T1 or less during the operation of the vehicle attitude stabilization control. The vehicle posture stability control can be performed mainly, and the cooperative control with the motor 3 can be simplified to avoid the complicated vehicle posture stability control. The first motor can output the motor torque necessary for the slip ratio control only when the slip ratio control needs to be performed because the slip ratio of the drive wheel 8 is equal to or greater than a predetermined value. By relaxing the restriction by the torque T1 to the second motor torque T2, it is possible to perform the slip ratio control even during the vehicle attitude stabilization control. Accordingly, the vehicle behavior can be effectively stabilized by enabling the vehicle posture stabilization control and the slip ratio control to be implemented while simplifying the vehicle posture stabilization control.

  The present invention relates to a technical field of a control device for a hybrid vehicle that travels by transmitting power output from at least one of an engine and a motor to drive wheels via a transmission.

DESCRIPTION OF SYMBOLS 1 Hybrid vehicle 2 Engine 3 Motor 4 Dual clutch transmission 4a 1st power transmission system 4b 2nd power transmission system 5 Propeller shaft 6 Differential device 7 Drive shaft 8 Drive wheel 9 Inverter 10 Battery 11a 1st clutch 11b 2nd Clutch 12a even speed stage 12b odd speed stage 14 ECU (vehicle behavior stability control means, slip ratio detection means, motor torque control means)
15 Brake pedal 16 Accelerator pedal

Claims (2)

A control device for a hybrid vehicle in which a clutch is provided between the engine and the motor, and the motive power generated by at least one of the engine and the motor is transmitted to the drive wheels to travel.
The engine while limiting the maximum output torque of the motor to be equal to or lower than a preset first motor torque in order to stabilize the vehicle posture when it is determined that the vehicle posture is in an unstable state. Vehicle posture stability control means for performing vehicle posture stability control for controlling only the output torque of
When the slip ratio of the drive wheel becomes equal to or higher than a predetermined value, a drive torque or a regenerative torque is applied to the motor so that the slip ratio of the drive wheel becomes a target slip ratio, and the drive wheel Slip rate control means for performing slip rate control to suppress the slip state of
When it is carried further the slip ratio control during the performance of the previous SL vehicle posture stability control, the slip ratio control means, the second to the maximum output torque of the motor is greater than the first motor torque A control device for a hybrid vehicle, comprising: motor torque control means for relaxing to motor torque.   The hybrid vehicle control device according to claim 1, wherein the first motor torque is zero torque.

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