vehicle

Abstract

To prevent a rotational speed of an internal combustion engine from largely changing during slip control of a start clutch when an input / output torque of a rotary electric machine is restricted in a vehicle including the internal combustion engine and the rotary electric machine as the power source.SOLUTION: In a vehicle 1 having a power source including an internal combustion engine 10 and a MG 30, an HV-ECU 100 performs control such that the change rate of an output torque of the power source and the change rate of a transmission torque capacity of the start clutch 40 become small when the input / output torque of the MG 30 is restricted during the slip control of the start clutch 40.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a vehicle, and more particularly to a vehicle equipped with an internal combustion engine and a rotating electric machine as power sources. [Background technology]

[0002] There is known a vehicle equipped with a starting clutch that can switch between transmitting and cutting off the power in a power transmission path that transmits the power of a power source to a driving wheel.For example, Japanese Patent Application Laid-Open Publication No. 2011-94756 (Patent Document 1) discloses that, in order to achieve good responsiveness and reduced shock, the torque capacity (transmission torque capacity) and input torque of the starting clutch are controlled so that the input shaft rotation speed of the starting clutch becomes a target input shaft rotation speed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-94756 A Summary of the Invention [Problem to be solved by the invention]

[0004] In Patent Document 1, the torque capacity and input torque of the starting clutch are controlled so that the input shaft rotation speed of the starting clutch becomes the target input shaft rotation speed. When the starting clutch is in a slipping state (half-engaged state), the driving force of the vehicle depends on the torque capacity of the starting clutch, so there is a concern that the driving force will change due to a change in the torque capacity, and drivability will deteriorate. Therefore, when the starting clutch is in a slipping state, it is desirable to control the output torque of the power source in order to maintain the input shaft rotation speed of the starting clutch at a predetermined value.

[0005] Patent Document 1 describes that a power source provided with a motor in addition to an internal combustion engine may be used as the power source. In a so-called hybrid vehicle equipped with an internal combustion engine and a motor as a power source, the input / output torque (motor torque) of the motor is input to the starting clutch in addition to the output torque (engine torque) of the internal combustion engine. In a hybrid vehicle, the motor torque may be limited depending on the state of the battery that supplies power to the motor. When the motor torque is limited, the output torque of the power source is controlled mainly by the engine torque.

[0006] The responsiveness of the output torque of the power source and the transfer torque capacity of the starting clutch are different. For example, when the starting clutch is a hydraulic clutch (hydraulic friction engagement device), the responsiveness of the transfer torque capacity changes depending on the hydraulic oil temperature of the hydraulic clutch, and the responsiveness decreases when the hydraulic oil temperature decreases. When the starting clutch is in a slipping state, in order to maintain the input shaft rotation speed of the starting clutch at a predetermined value, it is desirable to control the output torque of the power source and the transfer torque capacity of the starting clutch so that they match. When a deviation occurs between the output torque of the power source and the transfer torque capacity of the starting clutch due to a difference in the responsiveness between the output torque of the power source and the transfer torque capacity of the starting clutch, the output torque of the power source and the transfer torque capacity of the starting clutch can be matched by controlling the motor torque, which has a relatively high responsiveness. However, when the motor torque is limited, it becomes difficult to match the output torque of the power source and the transfer torque capacity of the starting clutch using the motor torque. As a result, the discrepancy between the output torque of the power source and the transmission torque capacity of the starting clutch will become larger, and the rotational speed of the internal combustion engine (the input shaft rotational speed of the starting clutch) will decrease, causing the engine to stall, or the rotational speed of the internal combustion engine will increase, causing excessive slippage and reducing the durability of the starting clutch.

[0007] The object of the present disclosure is to prevent large changes in the rotational speed of the internal combustion engine during slip control of the starting clutch in a vehicle equipped with an internal combustion engine and a rotating electric machine as power sources when the input / output torque of the rotating electric machine is limited. [Means for solving the problem]

[0008] The vehicle disclosed herein includes a power source including an internal combustion engine and a rotating electric machine, a starting clutch provided in a power transmission path between the power source and drive wheels, and a control device that controls the power source and the starting clutch. When the input / output torque of the rotating electric machine is limited during slip control that controls the starting clutch to a half-engaged state, the control device controls the rate of change of the output torque of the power source and the rate of change of the transmission torque capacity of the starting clutch to be smaller than when the input / output torque of the rotating electric machine is not limited.

[0009] According to this configuration, when the input / output torque of the rotating electric machine is limited and the output torque of the power source cannot be controlled using the input / output torque of the rotating electric machine, which has a relatively high response, during slip control in which the starting clutch is controlled to a semi-engaged state, the rate of change of the output torque of the power source and the rate of change of the transfer torque capacity of the starting clutch are controlled to be smaller than when the input / output torque of the rotating electric machine is not limited. Because the rate of change of the output torque of the power source and the rate of change of the transfer torque capacity of the starting clutch are reduced, the deviation between the output torque of the power source and the transfer torque capacity of the starting clutch can be reduced, and large changes in the rotation speed of the internal combustion engine can be suppressed.

[0010] Preferably, the control device may control the rate of change of the output torque of the power source and the rate of change of the transmission torque capacity of the starting clutch to be small when the input / output torque of the rotating electric machine is limited and the responsiveness of the starting clutch is low.

[0011] For example, when the hydraulic pressure of the starting clutch is reduced to the extent that the stroke of the starting clutch is required before the starting clutch is engaged, and when the responsiveness of the starting clutch is low, the difference between the responsiveness of the output torque of the power source and the transfer torque capacity of the starting clutch becomes large, and there is a high possibility that the deviation between the output torque of the power source and the transfer torque capacity of the starting clutch becomes large. According to this configuration, when the input / output torque of the rotating electric machine is limited and the responsiveness of the starting clutch is low, the rate of change of the output torque of the power source and the rate of change of the transfer torque capacity of the starting clutch are controlled to be small. Therefore, when the difference between the responsiveness of the output torque of the power source and the transfer torque capacity of the starting clutch is large and there is a possibility that the deviation between the output torque of the power source and the transfer torque capacity of the starting clutch becomes large, the rate of change of the output torque of the power source and the rate of change of the transfer torque capacity of the starting clutch are reduced, so that the deviation between the output torque of the power source and the transfer torque capacity of the starting clutch can be reduced, and a large change in the rotation speed of the internal combustion engine can be suppressed. If the responsiveness of the starting clutch is not low, the rate of change of the output torque of the power source and the rate of change of the transmission torque capacity of the starting clutch are not controlled to be small, so that deterioration of drivability can be suppressed. Effect of the Invention

[0012] According to the present disclosure, in a vehicle equipped with an internal combustion engine and a rotating electric machine as power sources, when the input / output torque of the rotating electric machine is limited, it is possible to prevent the rotational speed of the internal combustion engine from changing significantly during slip control of the starting clutch. [Brief description of the drawings]

[0013] [Figure 1] 1 is a diagram showing an overall configuration of a vehicle 1 according to an embodiment of the present invention. [Diagram 2] 4 is a time chart at the time of starting. [Diagram 3] 3 is a flowchart showing an outline of processing executed by an HV-ECU 100 in the present embodiment. [Figure 4] 4 is a time chart at the time of starting in the present embodiment. [Diagram 5] 10 is a flowchart showing an outline of a process executed by an HV-ECU 100 in a modified example. [Figure 6] FIG. 13 is a diagram showing an example of a calculation map for a target torque upper limit change rate ΔTtu. [Figure 7] FIG. 13 is a diagram showing another example of a calculation map for a target torque upper limit change rate ΔTtu. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference characters and their description will not be repeated.

[0015] 1 is a diagram showing an overall configuration of a vehicle 1 according to this embodiment. The vehicle 1 is a hybrid vehicle equipped with an internal combustion engine 10 and a motor generator (hereinafter referred to as "MG") 30 as a power source.

[0016] The internal combustion engine 10 is, for example, a spark ignition internal combustion engine (gasoline engine). The internal combustion engine 10 may be a compression ignition internal combustion engine (diesel engine). The MG 30 is a rotating electric machine, for example, an interior permanent magnet (IPM) synchronous motor with a permanent magnet embedded in the rotor. The rotor shaft of the MG 30 is connected to the crankshaft (output shaft) of the internal combustion engine 10 via a K0 clutch 20. The rotor shaft of the MG 30 is also connected to the input shaft of an automatic transmission 50 via a starting clutch 40. The MG 30 operates as an electric motor (motor) and also as a generator.

[0017] The K0 clutch 20 is a hydraulic friction engagement device (hydraulic clutch) that interrupts or transmits power between the crankshaft of the internal combustion engine 10 and the rotor shaft of the MG 30. When the K0 clutch 20 is engaged, power transmission is possible between the crankshaft of the internal combustion engine 10 and the rotor shaft of the MG 30. When the K0 clutch 20 is released, power transmission between the crankshaft of the internal combustion engine 10 and the rotor shaft of the MG 30 is interrupted.

[0018] When the K0 clutch 20 is engaged and the MG 30 operates as an electric motor, the output torque of the MG 30 is input to the input shaft of the starting clutch 40 in addition to the output torque of the internal combustion engine 10, and the output torque of the MG 30 is added to the output torque of the internal combustion engine 10, making it possible to drive the drive wheels 70. When the K0 clutch 20 is engaged, the MG 30 operates as a generator by driving the MG 30 via the crankshaft of the internal combustion engine 10. The MG 30 can also perform regenerative power generation by the driven force (braking force) input from the drive wheels 70. When the internal combustion engine 10 is stopped, the internal combustion engine 10 can be cranked by the output torque of the MG 30 via the K0 clutch 20 to start the internal combustion engine 10. It is also possible to run the vehicle 1 only by the output torque of the MG 30 with the K0 clutch 20 released.

[0019] The starting clutch 40 is a hydraulic friction engagement device (hydraulic clutch) and interrupts or transmits power between the rotor shaft of the MG 30 and the input shaft of the automatic transmission 50. When the starting clutch 40 is engaged, power can be transmitted between the rotor shaft of the MG 30 and the input shaft of the automatic transmission 50. When the starting clutch 40 is released, power transmission between the rotor shaft of the MG 30 and the input shaft of the automatic transmission 50 is interrupted. By controlling the hydraulic pressure of the starting clutch 40, the starting clutch 40 can be put into a semi-engaged state and put into a slip state. In addition, by controlling the hydraulic pressure of the starting clutch 40, the transmission torque capacity of the starting clutch 40 can be controlled.

[0020] The automatic transmission 50 is a planetary gear type multi-speed automatic transmission, and each gear is achieved by controlling a combination of engagement and release of a plurality of friction engagement elements. The output shaft of the automatic transmission 50 is connected to a differential gear 60 via a propeller shaft. The differential gear 60 is connected to driving wheels 70 via a drive shaft.

[0021] A PCU (Power Control Unit) 80 converts DC power received from the power storage device 90 into AC power for driving the MG 30. The PCU 80 also converts AC power generated (regenerated) by the MG 30 into DC power for charging the power storage device 90. The PCU 80 is configured to include, for example, an inverter and a converter that boosts a DC voltage supplied to the inverter to a voltage equal to or higher than that of the power storage device 90.

[0022] The power storage device 90 is a rechargeable DC power source, and includes a secondary battery such as a lithium ion battery or a nickel metal hydride battery. The power storage device 90 is charged by receiving electric power generated by the MG 30. The power storage device 90 then supplies the stored electric power to the PCU 80, which drives the MG 30.

[0023] The power storage device 90 is provided with a monitoring unit 91. The monitoring unit 91 includes a voltage sensor, a current sensor, and a temperature sensor (none of which are shown) that respectively detect the voltage, input / output current, and temperature of the power storage device 90. The monitoring unit 91 outputs the detection values ​​of each sensor (the voltage, input / output current, and temperature of the power storage device 90) to a BAT-ECU (Electronic Control Unit) 110.

[0024] The vehicle 1 includes an HV-ECU 100, a BAT-ECU 110, and an E / G-ECU 120. Each ECU includes a CPU (Central Processing Unit), a memory, and an input / output buffer (not shown), and receives input of signals from various sensors, outputs control signals to each device, and controls each device.

[0025] The HV-ECU 100 outputs a command for controlling the internal combustion engine 10 to the E / G-ECU 120, and outputs a command for controlling the MG 30 to the PCU 80. The HV-ECU 100 also controls the K0 clutch 20, the starting clutch 40, and the automatic transmission 50.

[0026] The BAT-ECU 110 calculates the SOC (State Of Charge) of the power storage device 90 based on the detection values ​​of the sensors output from the monitoring unit 91, and outputs the SOC to the HV-ECU 100.

[0027] The E / G-ECU 120 controls the output of the internal combustion engine 10 based on commands from the HV-ECU 100. Note that the E / G-ECU 120 may control the K0 clutch 20, the starting clutch 40, and the automatic transmission 50 based on commands from the HV-ECU 100, or a new ECU (drive ECU) may be provided to control the K0 clutch 20, the starting clutch 40, and the automatic transmission 50. Each of these ECUs corresponds to the "control device" of the present disclosure.

[0028] The accelerator opening sensor 101 detects an accelerator opening AP, which is the amount of depression of the accelerator pedal. Note that instead of the accelerator opening sensor 101, a throttle opening sensor that detects a throttle opening of the internal combustion engine 10 may be used. The engine speed sensor 102 detects the rotation speed NE of the internal combustion engine. The oil temperature sensor 103 detects a hydraulic oil temperature To, which is the temperature of the hydraulic oil in the starting clutch 40.

[0029] In the vehicle 1, for example, when the K0 clutch 20 is engaged and the output torque (engine torque) of the internal combustion engine 10 and the input / output torque (motor torque) of the MG 30 are used to start the vehicle, slip control of the starting clutch 40 is performed. FIG. 2 is a time chart at the time of starting the vehicle. When the K0 clutch 20 is engaged and the internal combustion engine 10 is idling and the vehicle 1 is stopped, the starting clutch 40 is released. In this state, when the accelerator pedal is depressed at time t1, a required driving force Fdt is set according to the magnitude of the accelerator opening AP. When the required driving force Fdt is set, a target torque Tt is calculated by multiplying a value obtained by dividing the required driving force Fdt by the gear ratio of the automatic transmission 50 and the reduction ratio of the differential gear 60, by the radius of the drive wheels 70. The target engine torque Tet is calculated by subtracting a target motor torque Tmt (a positive value when discharging from the power storage device 90) based on the SOC of the power storage device 90 from the target torque Tt. The target output torque Tdt (=Tet+Tmt) of the internal combustion engine 10 and MG 30 as the power source becomes the target torque Tt. During slip control of the starting clutch 40, the target transmission torque capacity Tct of the starting clutch 40 is set to the target torque Tt.

[0030] When the accelerator pedal is depressed at time t1 with the K0 clutch 20 engaged, the internal combustion engine 10 idling, and the starting clutch 40 disengaged, the target torque Tt rises as shown in the middle of FIG. 2. Then, the engine torque Te is controlled to the target engine torque Tet and the motor torque Tm is controlled to the target motor torque Tmt so that the output torque Td of the power source becomes the target torque Tt (=target output torque Tdt). In addition, the transmission torque capacity Tc of the starting clutch 40 is controlled to match the target torque Tt. As a result, the starting clutch 40 is in a half-engaged slip state, and the input shaft rotation speed Ni of the automatic transmission 50 (output shaft rotation speed of the starting clutch 40) increases as shown in the lower part of FIG. 2.

[0031] The responsiveness of the output torque Td of the power source (the sum of the engine torque Te and the motor torque Tm) differs from the responsiveness of the transmission torque capacity Tc of the starting clutch 40. In the example shown in FIG. 2, the responsiveness of the transmission torque capacity Tc is lower than the responsiveness of the output torque Td. For this reason, the transmission torque capacity Tc rises later than the output torque Td (= Te + Tm) shown by the dashed line. In FIG. 2, the transmission torque capacity Tc shows the change in the transmission torque capacity Tc in cold regions. The transmission torque capacity Tc shown by the two-dot chain line shows the case where the hydraulic oil temperature of the starting clutch 40 is low, and the one-dot chain line shows the transmission torque capacity Tc when the hydraulic oil temperature rises after warm-up is complete.

[0032] The output torque Td of the power source and the transmission torque capacity Tc of the starting clutch 40 are controlled to match the target torque Tt. However, because the responsiveness of the output torque Td and the transmission torque capacity Tc differs, a difference occurs between the output torque Td and the transmission torque capacity Tc as shown in the shaded area in FIG. 2. In this embodiment, in order to eliminate the difference shown in the shaded area in FIG. 2, the motor torque Tm is controlled (increased or decreased) so that the output torque Td and the transmission torque capacity Tc match. In the example shown in FIG. 2, the target motor torque Tmt is corrected in the negative direction by the torque amount of the shaded area, so that the output torque Td matches the transmission torque capacity Tc. For example, the motor torque Tm is feedback-controlled so that the change amount ΔNE of the engine rotation speed NE becomes zero, thereby controlling the output torque Td to match the transmission torque capacity Tc. (In the case of FIG. 2, MG 30 is controlled so as to generate a negative torque corresponding to the shaded area.) As a result, engine speed NE is maintained at a predetermined value (amount of change ΔNE in engine speed NE is maintained at approximately zero) as shown by a solid line in the lower part of FIG. 2. Input shaft rotation speed Ni of automatic transmission 50 (output shaft rotation speed of starting clutch 40) increases (vehicle speed of vehicle 1 increases), the amount of slip of starting clutch 40 (difference between engine rotation speed NE and input shaft rotation speed Ni) decreases, and at time t2, when engine rotation speed NE and input shaft rotation speed Ni match, slip control of starting clutch 40 ends and starting clutch 40 is fully engaged.

[0033] For example, when the temperature of the power storage device 90 is high, the charge / discharge power (charge / discharge current) of the power storage device 90 may be limited in order to protect the power storage device 90 from deterioration. When the charge / discharge power of the power storage device 90 is limited, the motor torque Tm is also limited, making it difficult to control the output torque Td to match the transmission torque capacity Tc using feedback control of the motor torque Tm, and the engine rotation speed NE changes. In particular, when the difference between the output torque Td and the transmission torque capacity Tc is large, the change amount ΔNE of the engine rotation speed NE becomes large. For example, as shown by the dashed line in the middle part of FIG. 2, when the operating oil temperature rises and the responsiveness of the transmission torque capacity Tc is relatively high, the difference between the output torque Td and the transmission torque capacity Tc is relatively small as shown by the left diagonal line, and therefore the increase amount (change amount ΔNE) of the engine rotation speed NE is small as shown by the dashed line in the lower part. However, when the hydraulic oil temperature is low, as shown by the two-dot chain line in the middle of Figure 2, the deviation between the output torque Td and the transmission torque capacity Tc becomes larger as the right-hand shaded area is added to the left-hand shaded area, and the amount of increase in the engine rotation speed NE (amount of change ΔNE) becomes larger, as shown by the two-dot chain line in the lower part.

[0034] If the engine speed NE increases significantly, the amount of slip in the starting clutch 40 becomes excessive, which may reduce the durability of the starting clutch 40. If the responsiveness of the transmission torque capacity Tc is higher (faster) than the responsiveness of the output torque Td, the engine speed NE decreases significantly, which may cause the engine to stall.

[0035] In this embodiment, when the motor torque Tm is limited and the input / output torque of MG30 is limited, the rate of change of the output torque Td and the transmission torque capacity Tc is reduced to prevent the engine rotation speed NE from changing significantly.

[0036] 3 is a flowchart showing an outline of the process executed by the HV-ECU 100 in this embodiment. This flowchart is repeatedly processed at predetermined intervals while the vehicle 1 is traveling (from system ON (ignition ON) to system OFF (ignition OFF) of the vehicle 1). In step (hereinafter, step is abbreviated as "S") 10, it is determined whether or not slip control of the starting clutch 40 is in progress. For example, when the K0 clutch 20 is in an engaged state and the vehicle speed is equal to or lower than a predetermined value, it is determined that slip control is in progress. If a negative determination is made in S10 that the starting clutch 40 is not in slip control, the current routine is terminated. If a positive determination is made in S10, the routine proceeds to S11.

[0037] In S11, it is determined whether the charging power Win or the discharging power Wout of the power storage device 90 is restricted. For example, it is determined that the charging power Win or the discharging power Wout is restricted when the temperature of the power storage device 90 detected by the monitoring unit 91 is higher than a first predetermined temperature and the charging power Win and the discharging power Wout are limited from the viewpoint of protecting the power storage device 90, when the temperature of the power storage device 90 is lower than a second predetermined temperature and the discharging power Wout from the power storage device 90 is restricted, etc. If a positive determination is made in S11, the process proceeds to S12. If a negative determination is made in S11, the current routine is terminated.

[0038] When the charging power Win is restricted, the power generated by MG 30 is limited, and therefore the negative torque (input torque) of MG 30 is limited. When the discharging power Wout is restricted, the power supplied to MG 30 is limited, and therefore the positive torque (output torque) of MG 30 is limited. Therefore, when the input / output torque (motor torque Tm) of MG 30 is limited, a positive determination is made in S11.

[0039] In S12, it is determined whether the hydraulic oil temperature To, which is the temperature of the hydraulic oil of the starting clutch 40 detected by the oil temperature sensor 103, is equal to or lower than a predetermined value α. The predetermined value α is set in advance by experiment or the like. The predetermined value α is the temperature of the hydraulic oil at which the viscosity of the hydraulic oil is high, the responsiveness of the starting clutch 40 decreases, and the difference between the responsiveness of the output torque Td and the transmission torque capacity Tc becomes large, so that when the motor torque Tm is limited, the change amount ΔNE of the engine rotation speed NE becomes unacceptable even when feedback control of the motor torque Tm is used. If the hydraulic oil temperature To exceeds the predetermined value α, a negative determination is made in S12, and the current routine is terminated. If the hydraulic oil temperature To is equal to or lower than the predetermined value α, a positive determination is made in S12, and the routine proceeds to S13.

[0040] In S13, a driving force upper limit change rate ΔFdL, which is an upper limit value of the rate of change of the driving force Fd of the vehicle 1, is calculated based on the hydraulic oil temperature To. A calculation map for the driving force upper limit change rate ΔFdL using the hydraulic oil temperature To as a parameter is stored in memory, and the driving force upper limit change rate ΔFdL is calculated based on the hydraulic oil temperature To by searching the map. The driving force upper limit change rate ΔFdL is a value at which the change amount ΔNE of the engine rotation speed NE becomes equal to or less than a predetermined value even without feedback control of the motor torque Tm, and is determined in advance by experiments or the like, and is set to a smaller value as the hydraulic oil temperature To is lower.

[0041] In the next S14, an allowable change amount ΔNEa in the engine speed NE is calculated based on the accelerator opening AP detected by the accelerator opening sensor 101. When the driver intends to accelerate, if the amount of slip is within a range that does not deteriorate the durability of the starting clutch 40, the change amount ΔNE becomes large, and even if the engine speed NE increases, the driver does not feel uncomfortable and drivability is improved. Therefore, when the accelerator opening AP is large, an increase in the engine speed NE is allowed and the allowable change amount ΔNEa is calculated based on the accelerator opening AP to improve drivability. The allowable change amount ΔNEa is obtained in advance by experiment or the like, and is set to a larger value as the accelerator opening AP increases.

[0042] In the next S15, the driving force upper limit change rate ΔFdL calculated in S13 is corrected using the allowable change amount ΔNEa calculated in S14 to calculate the target driving force upper limit change rate ΔFdT. For example, if the change amount ΔNE due to the driving force upper limit change rate ΔFdL is smaller than the allowable change amount ΔNEa, the driving force upper limit change rate ΔFdL is increased to obtain the target driving force upper limit change rate ΔFdT. If the change amount ΔNE due to the driving force upper limit change rate ΔFdL is larger than the allowable change amount ΔNEa, the driving force upper limit change rate ΔFdL is set as the target driving force upper limit change rate ΔFdT.

[0043] In S16, an upper limit value Ttu of the target torque Tt is set based on the target driving force upper limit change rate ΔFdT. The upper limit value Ttu is a value that guards the upper limit of the target torque Tt so that the change rate of the driving force Fd of the vehicle 1 does not exceed the target upper limit change rate ΔFdt. The target torque Tt is calculated based on the required driving force Fdt according to the accelerator opening AP, but by guarding the upper limit of the target torque Tt with the upper limit value Ttu, the change rate of the driving force Fd of the vehicle 1 does not exceed the target upper limit change rate ΔFdt, and the engine rotation speed NE is prevented from changing significantly. For example, the upper limit value Ttu can be set to a value obtained by adding the change rate of the target torque Tt corresponding to the target upper limit change rate ΔFd (target torque change rate ΔTt) to the target torque Tt (previous value) calculated in the previous routine. (Upper limit value Ttu=target torque Tt (previous value)+target torque change rate ΔTt) In S17, the target torque Tt is guarded against by the upper limit value Ttu set in S16. If the target torque Tt calculated based on the required driving force Fdt according to the accelerator opening AP exceeds the upper limit value Ttu, the target torque Tt is rewritten to the upper limit value Ttu (Tt=Ttu). If the target torque Tt is equal to or less than the upper limit value Ttu, the target torque Tt is not rewritten. In addition, the currently calculated target torque Tt is stored in memory as the target torque Tt (previous value), and the current routine is then terminated.

[0044] FIG. 4 is a time chart at the time of starting in this embodiment. When the K0 clutch 20 is engaged, the internal combustion engine 10 is idling, the vehicle 1 is stopped, and the starting clutch 40 is released, and the accelerator pedal is depressed at time t1, the target torque Tt increases. As the target torque Tt increases, the engine torque Te is controlled to the target engine torque Tet and the motor torque Tm is controlled to the target motor torque Tmt so that the output torque Td of the power source becomes the target torque Tt. In addition, the transmission torque capacity Tc of the starting clutch 40 is controlled to match the target torque Tt. As a result, the starting clutch 40 is in a half-engaged slip state, and the input shaft rotation speed Ni of the automatic transmission 50 (the output shaft rotation speed of the starting clutch 40) increases as shown in the lower part of FIG.

[0045] When the input / output torque (motor torque Tm) of the MG 30 is limited (positive determination in S11) and the responsiveness of the starting clutch 40 is low (positive determination in S12), an upper limit value Ttu of the target torque Tt is set (S13 to S16), the target torque Tt is guarded by the upper limit value Ttu, and the rate of change of the target torque Tt is limited. Therefore, as shown in the middle part of FIG. 4, the increase gradient of the target torque Tt becomes small. Therefore, the rate of change of the output torque Td and the transmission torque capacity Tc becomes small, and the increase gradient of the output torque Td and the transmission torque capacity Tc becomes small. As a result, even if the responsiveness of the starting clutch 40 is low, the deviation between the output torque Td and the transmission torque capacity Tc becomes small, and the increase gradient of the output torque Td becomes small, so that the increase amount of the engine rotation speed NE (amount of change ΔNE) can be reduced, as shown in the lower part of FIG. 4. In addition, the driving force upper limit change rate ΔFdL is corrected in accordance with the driver's intention to accelerate by using the allowable change amount ΔNEa, which is set to a larger value as the accelerator opening degree AP increases, and the upper limit value Ttu is set. This allows an amount of slip within a range that does not deteriorate the durability of the starting clutch 40 and allows an increase in the engine rotation speed NE, thereby improving acceleration performance and drivability.

[0046] In this embodiment, in S12, it is determined that the responsiveness of the starting clutch 40 is low based on the hydraulic oil temperature To. However, instead of or in addition to this determination, it may be determined from the hydraulic oil pressure that the hydraulic oil pressure of the starting clutch 40 has been reduced to such an extent that a stroke of the starting clutch 40 is required before the starting clutch 40 begins to engage. Also, S12 may be eliminated, and the process may proceed to S13 if a positive determination is made in S11.

[0047] In this embodiment, in S14, the allowable change amount ΔNEa of the engine rotation speed NE is calculated based on the accelerator opening AP. However, the allowable change amount ΔNEa may be calculated based on the change amount (change rate) of the accelerator opening AP. In this case, the allowable change amount ΔNEa is set to a larger value as the change amount of the accelerator opening AP increases. Also, S14 and S15 may be eliminated, and the upper limit value Ttu may be obtained without calculating the target driving force upper limit change rate ΔFdT. In this case, the upper limit value Ttu may be calculated based on the driving force upper limit change rate ΔFdL.

[0048] (Modification) In the above embodiment, in steps S13 to S17, the upper limit value Ttu of the target torque Tt is set based on the driving force upper limit change rate ΔFdL calculated using the hydraulic oil temperature To as a parameter, thereby controlling the rate of change of the output torque Td and the rate of change of the transmission torque capacity Tc to be small. However, the rate of change of the target torque Tt may be limited without calculating the driving force upper limit change rate ΔFdL and the upper limit value Ttu, thereby controlling the rate of change of the output torque Td and the rate of change of the transmission torque capacity Tc to be small.

[0049] Fig. 5 is a flowchart showing an outline of the process executed by HV-ECU 100 in the modified example. In this flowchart, S13 to S17 in the flowchart of Fig. 3 are replaced with S30, and if a positive determination is made in S12, the process of S30 is executed.

[0050] In S30, the hydraulic oil temperature To and the accelerator opening AP are used to search the map to calculate the upper limit of the change rate of the target torque Tt. FIG. 6 is a diagram showing an example of a calculation map for the target torque upper limit change rate ΔTtu. In this map, the change rate of the target torque Tt that "contains the change amount ΔNE of the engine rotation speed NE within an allowable range and satisfies drivability (acceleration feeling)" during slip control of the starting clutch 40 in a state where the motor torque Tm is limited is obtained by experiment or the like using the hydraulic oil temperature To and the accelerator opening AP as parameters, and the obtained change rate of the target torque Tt is set as the target torque upper limit change rate ΔTtu. The lower the hydraulic oil temperature To, the lower the responsiveness of the transmission torque capacity Tc is, and the larger the accelerator opening AP, the higher the acceleration feeling is to improve the drivability, so the lower the hydraulic oil temperature To and the smaller the accelerator opening AP, the smaller the target torque upper limit change rate ΔTtu tends to be set.

[0051] In the next step S31, the target torque change rate ΔTt, which is the change amount (slope) of the target torque Tt, is limited by the target torque upper limit change rate ΔTtu. The target torque change rate ΔTt is calculated from the deviation between the previous target torque Tt and the current target torque Tt, and if the target torque change rate ΔTu exceeds the target torque upper limit change rate ΔTtu, the current target torque Tt is corrected by decreasing it so that the target torque change rate ΔTu falls within the target torque upper limit change rate ΔTtu.

[0052] Even in this modified example, the input / output torque (motor torque Tm) of MG30 is limited, and when the responsiveness of the starting clutch 40 is low, the rate of change of the target torque Tt (target torque change rate ΔTt) is limited and the rates of change of the output torque Td and the transmission torque capacity Tc become small, thereby making it possible to reduce the amount of increase in the engine rotation speed NE.

[0053] In the above embodiment, an example in which the responsiveness of the transmission torque capacity Tc is slower (lower) than the responsiveness of the output torque Td has been described. However, the present disclosure can be applied even when the responsiveness of the transmission torque capacity Tc is faster (higher) than the responsiveness of the output torque Td. For example, when the hydraulic oil temperature To of the starting clutch 40 is low, the responsiveness of the transmission torque capacity Tc is lower than the responsiveness of the output torque Td, but when the hydraulic oil temperature To rises to a predetermined temperature β, the responsiveness of the transmission torque capacity Tc and the output torque Td become almost equal, and when the hydraulic oil temperature To further rises and the viscosity decreases, the responsiveness of the transmission capacity Tc becomes higher than the responsiveness of the output torque Td. FIG. 7 is a diagram showing an example of a calculation map of the target torque upper limit change rate ΔTtu in such a vehicle in a modified example. At the predetermined temperature β at which the responsiveness of the transmission torque capacity Tc and the output torque Td becomes almost equal, the present disclosure can be applied to a vehicle in which the responsiveness of the transmission torque capacity Tc is lower than the responsiveness of the output torque Td. The target upper limit change rate ΔTtu becomes smaller as the hydraulic oil temperature To decreases from the predetermined temperature β or increases from the predetermined temperature β. In a region where the hydraulic oil temperature To is higher than the predetermined temperature β, when the input / output torque of the MG 30 is limited during slip control of the starting clutch 40, the change rate of the output torque Td and the change rate of the transmission torque capacity Tc are controlled to be smaller than when the input / output torque of the MG 30 is not limited, thereby making it possible to suppress the occurrence of engine stall.

[0054] The following are examples of embodiments of the present disclosure. 1) A vehicle including a power source (10, 30) including an internal combustion engine (10) and a rotating electric machine (30), a cut-off clutch (20) that cuts off power transmission between the internal combustion engine (10) and the rotating electric machine (30), a starting clutch (40) provided in a power transmission path between the power source (10, 30) and a drive wheel (70), and a control device (100) that controls the power source (10, 30), the cut-off clutch (20), and the starting clutch (40), wherein, when the cut-off clutch (20) is connected and during slip control that controls the starting clutch (40) to a semi-engaged state, when the input / output torque of the rotating electric machine (30) is limited, the control device (100) controls the rate of change of the output torque of the power source (20, 30) and the rate of change of the transmission torque capacity of the starting clutch (40) so as to be smaller compared to when the input / output torque of the rotating electric machine (30) is not limited.

[0055] 2) In 1, the system further includes an electricity storage device (90) that supplies and receives electric power to and from the rotating electric machine (30), and the control device (100) determines that when the input power and output power of the electricity storage device (90) are limited, the input / output torque of the rotating electric machine (30) is limited.

[0056] 3) In 1 or 2, the control device (100) calculates a target torque based on the accelerator opening degree, and controls the output torque of the power source (20, 30) and the transmission torque capacity of the starting clutch (40) to become the target torque. When the input power and output power of the power storage device (90) are limited and the difference between the magnitude of the output torque of the power source (20, 30) and the transmission torque capacity of the starting clutch (30) is equal to or greater than a predetermined value, the control device (100) controls the rate of change of the output torque of the power source (20, 30) and the rate of change of the transmission torque capacity of the starting clutch (30) to become smaller.

[0057] In 4)3, the starting clutch (40) is a hydraulic clutch, and when the hydraulic oil temperature of the starting clutch (40) is equal to or lower than a predetermined value, the control device (100) determines that the difference between the output torque of the power source (20, 30) and the transmission torque capacity of the starting clutch (30) is equal to or greater than a predetermined value.

[0058] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, not by the description of the embodiments described above, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0059] 1 vehicle, 10 internal combustion engine, 20 K0 clutch, 30 motor generator (MG), 40 starting clutch, 50 automatic transmission, 60 differential gear, 70 drive wheels, 80 PCU, 90 power storage device, 91 monitoring unit, 100 HV-ECU, 101 accelerator opening sensor, 102 engine speed sensor, 103 oil temperature sensor, 110 BAT-ECU, 120 E / G-ECU.

Claims

1. A power source including an internal combustion engine and a rotating electric machine; a starting clutch provided in a power transmission path between the power source and a drive wheel; A vehicle including the power source and a control device that controls the starting clutch, the control device calculates a target torque based on an accelerator operation amount, and controls the output torque of the power source and the transfer torque capacity of the starting clutch to become the target torque; the control device controls an input / output torque of the rotary electric machine so that the output torque of the power source coincides with the transmission torque capacity of the starting clutch during slip control for controlling the starting clutch to a half-engaged state, A vehicle in which, when the input / output torque of the rotating electric machine is limited during the slip control that controls the starting clutch to a semi-engaged state, the control device controls the rate of change of the output torque of the power source and the rate of change of the transmission torque capacity of the starting clutch to be smaller compared to when the input / output torque of the rotating electric machine is not limited.

2. 2. The vehicle according to claim 1, wherein the control device controls the rate of change of the output torque of the power source and the rate of change of the transmission torque capacity of the starting clutch to be small when the input / output torque of the rotating electric machine is limited and the responsiveness of the starting clutch is low.

3. 3. The vehicle according to claim 1, wherein the control device sets an upper limit value for a rate of change of the driving force of the vehicle in accordance with the responsiveness of the starting clutch, and controls a rate of change of the output torque of the power source and a rate of change of the transmission torque capacity of the starting clutch based on the upper limit value of the rate of change of the driving force.

4. 4. The vehicle according to claim 3, wherein the control device calculates a target torque based on an accelerator operation amount, controls the output torque of the power source and the transmission torque capacity of the starting clutch to become the target torque, and controls the rate of change of the output torque of the power source and the rate of change of the transmission torque capacity of the starting clutch by setting an upper limit value of the target torque based on an upper limit value of the rate of change of the driving force.

5. 5. The vehicle according to claim 4, wherein the control device calculates a corrected upper limit value by correcting an upper limit value of the rate of change of the driving force based on the accelerator operation amount, and sets an upper limit value of the target torque based on the corrected upper limit value.

6. The starting clutch is a hydraulic friction engagement device, 3. The vehicle according to claim 2, wherein the control device calculates a target torque based on an accelerator operation amount, controls the output torque of the power source and the transmission torque capacity of the starting clutch to become the target torque, and controls the rate of change of the output torque of the power source and the rate of change of the transmission torque capacity of the starting clutch by setting an upper limit value of a rate of change of the target torque based on a hydraulic oil temperature, which is the temperature of the hydraulic oil in the starting clutch, and the accelerator operation amount.

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