CONTROL UNIT FOR HYBRID VEHICLE

Abstract

Control unit for a hybrid vehicle (1), wherein the hybrid vehicle (1) comprises: an internal combustion engine (2) and a motor (4) as drive sources to transmit power to a drive wheel (5); an automatic transmission (3) that changes the speed of the internal combustion engine (2) and transmits the rotation to the drive wheel (5);a power transmission mechanism (26) which forms a disengagement state to interrupt the power transmission between the internal combustion engine (2) and the drive wheel (5), or forms an engagement state to enable the power transmission between the internal combustion engine (2) and the drive wheel (5), and an energy storage device (33) which supplies electrical power to the motor (4), wherein the motor (4) is configured to deliver torque during an incomplete engagement period of the power transmission mechanism (26) when a gear position is shifted in the automatic transmission (3), wherein the control unit comprises the following; a control section (10) which, during gear shifting, changes the disengagement speed of the power transmission mechanism (26) depending on the amount of current stored in the power storage device (33), wherein, if the amount of current stored in the current storage device (33) is not less than a predetermined amount of stored current and auxiliary torque output control is to be performed, the control section (10) sets the disengagement speed higher than in a case where the amount of stored current is less than the predetermined amount of stored current, and wherein the control section (10) changes the disengagement speed from a first speed at the beginning of the shifting process to a second speed which is higher than the first speed, after a prescribed amount of auxiliary torque has been delivered from the motor (4) to the drive wheel (5).

Description

[Technical field]

[0001] The present invention relates to a control unit for a hybrid vehicle. [Background of the technology]

[0002] In JP 2001-153 218 A, it is disclosed that a technique for limiting the decrease in torque transmitted to the wheels by transmitting torque from an electric motor to the wheels when a clutch is disengaged by a shifting operation to stop the transmission of torque from an internal combustion engine to the wheels controls a time period required for the shifting operation based on a result of determining the torque that can be delivered to the wheels by the electric motor to limit the decrease in torque transmitted to the wheels.

[0003] US Patent 2012 / 0004064A1 discloses a control device for a power transmission device with a regenerative electric motor via a step-shift mechanism. During a gear change, a motor regulates the speed of an input shaft of a transmission mechanism during regeneration to prevent the gear shift shock at the end stage of the gear change. This is achieved by means of hydraulic control prior to the final stage of the gear change, thereby causing the motor to perform a regeneration cycle and preventing a decrease in regeneration efficiency. [Summary of the invention][Technical problem]

[0004] Although the technique described in JP 2001-153 218 A controls the time required for the switching process as the torque delivered by the electric motor to the wheels decreases, controlling the time required for the switching process is not sufficient, and there is still a need for improvement in ensuring the driving performance of a vehicle.

[0005] Under these circumstances, the present invention relates to the provision of a control unit for a hybrid vehicle which is able to ensure the driving performance of a vehicle more effectively. [Solution to the task]

[0006] To solve the problem described above, the present invention provides a control unit for a hybrid vehicle comprising an internal combustion engine and a motor as a drive source, which transmits power to a drive wheel, an automatic transmission that changes the speed of the internal combustion engine and transmits the rotation to the drive wheel, a power transmission mechanism that forms a disengagement state to interrupt the power transmission between the internal combustion engine and the drive wheel, or an engagement state to enable the power transmission between the internal combustion engine and the drive wheel, and an energy storage device that supplies electrical power to the motor, wherein the motor is caused to deliver torque during an incomplete engagement period of the power transmission mechanism when a gear position is shifted in the automatic transmission.The control unit is configured to include a control section that, during gear shifting, changes the disengagement speed of the power transmission mechanism depending on the amount of current stored in the power storage device. If the amount of current stored in the power storage device is not less than a predetermined amount and auxiliary torque output control is required, the control section sets the disengagement speed higher than if the amount of current stored is less than the predetermined amount. Furthermore, after a prescribed amount of auxiliary torque has been delivered from the engine to the drive wheel, the control section changes the disengagement speed from a first speed at the beginning of the shifting process to a second speed that is higher than the first speed. [Advantageous effect of the invention]

[0007] As described above, the present invention enables a more effective guarantee of a vehicle's driving performance. [Brief description of the drawings] [ Fig. 1] Fig. Figure 1 is a schematic representation of the configuration of a hybrid vehicle according to an embodiment of the present invention. [ Fig. 2] Fig. Figure 2 is a diagram showing the outline of a clutch control process by a control unit for the hybrid vehicle according to one embodiment of the present invention. [ Fig. 3] Fig. Figure 3 is a flowchart showing a method for the clutch control process by the control unit for the hybrid vehicle according to one embodiment of the present invention. [ Fig. 4] Fig. Figure 4 is a time diagram showing changes in the disengagement and engagement speeds of a clutch due to the clutch control process by the control unit for the hybrid vehicle according to one embodiment of the present invention in a case where, based on an actuation amount of the accelerator pedal, it is determined that there is a requirement to improve performance. [Figure 5] Fig. Figure 5 is a time diagram showing changes in the disengagement and engagement speed of the clutch due to the clutch control process by the control unit for the hybrid vehicle according to one embodiment of the present invention in a case where, based on the selection of a driving mode by a driver, it is determined that there is a requirement to improve performance. [ Fig. 6] Fig. Figure 6 is a flowchart showing the sequence of a clutch control process by a control unit for a hybrid vehicle according to a first amendment of one embodiment of the present invention. [ Fig. 7] Fig. Figure 7 is a time diagram showing changes in the disengagement and engagement speeds of a clutch due to the clutch control process by the control unit for the hybrid vehicle according to the first amendment of one embodiment of the present invention in a case where, based on an actuation amount of the accelerator pedal, it is determined that there is a requirement to improve performance. [ Fig. 8] Fig. Figure 8 is a flowchart showing the sequence of a clutch control process by a control unit for a hybrid vehicle according to a second amendment of one embodiment of the present invention. [ Fig. 9] Fig. Figure 9 is a time diagram showing changes in the disengagement and engagement speeds of a clutch due to the clutch control process by the control unit for the hybrid vehicle according to the second amendment of one embodiment of the present invention in a case where, based on an actuation amount of the accelerator pedal, it is determined that there is a requirement to improve performance. [Description of an embodiment]

[0008] A control unit for a hybrid vehicle according to an embodiment of the present invention is a control unit for a hybrid vehicle comprising an internal combustion engine and a motor as a drive source, which transmits power to a drive wheel, an automatic transmission that changes the speed of the internal combustion engine and transmits the rotation to the drive wheel, a power transmission mechanism that forms a disengagement state to interrupt the power transmission between the internal combustion engine and the drive wheel, or an engagement state to enable the power transmission between the internal combustion engine and the drive wheel, and an energy storage section that supplies electrical power to the motor, wherein the motor is caused to deliver torque during an incomplete engagement period of the power transmission mechanism when a gear position is shifted in the automatic transmission.The control unit is configured to include a control section that changes the release speed of the power transmission mechanism when the gear position in the automatic transmission is changed, depending on the amount of current stored in the power storage section.

[0009] Thus, according to one embodiment of the present invention, the control unit for the hybrid vehicle is able to ensure the driving performance of a vehicle more effectively. [Version]

[0010] A hybrid vehicle comprising a control unit mounted according to an embodiment of the present invention is described below with reference to the drawings.

[0011] In Fig. 1 is a hybrid vehicle 1 according to an embodiment of the present invention configured to include an internal combustion engine 2, a transmission 3 as an automatic transmission, a motor generator 4 as a motor, a drive wheel 5, an HCU (Hybrid Control Unit) 10 as a control section encompassing the hybrid vehicle 1, an ECM (Engine Control Module) 11 controlling the internal combustion engine 2, a TCM (Transmission Control Module) 12 controlling the transmission 3, an ISGCM (Integrated Starter Generator Control Module) 13, an INVCM (Inverter Control Module) 14, and a BMS (Battery Management System) 16.

[0012] In the internal combustion engine 2, a plurality of cylinders are formed. In the present embodiment, the internal combustion engine 2 is configured such that it goes through a series of four strokes for each cylinder, consisting of the intake stroke, the compression stroke, the expansion stroke, and the exhaust stroke.

[0013] An ISG (Integrated Starter Generator) 20 and a starter 21 are coupled to the internal combustion engine 2. The ISG 20 is coupled to a crankshaft 18 of the internal combustion engine 2 via a belt 22 and the like. The ISG 20 functions as an electric motor that rotates the internal combustion engine 2 by supplying it with electrical power for rotation, and as an electric generator that converts the rotational force supplied by the crankshaft 18 into electrical power.

[0014] In the present embodiment, the ISG 20 operates as an electric motor under the control of the ISGCM 13, thereby restarting the combustion engine 2 from a state stopped by an idle-stop function. The ISG 20 can also assist the hybrid vehicle 1 while driving by functioning as an electric motor.

[0015] The starter 21 is configured to include a motor and a pinion gear (not shown). The starter 21 is designed to rotate the crankshaft 18 by turning the engine and to provide torque to the internal combustion engine 2 during starting. As described above, the internal combustion engine 2 is started by the starter 21 and restarted by the ISG 20 when it is stopped by the idle stop function.

[0016] The transmission 3 is suitable for changing the rotational speed supplied by the internal combustion engine 2 and for driving the drive wheel 5 via a drive shaft 23. The transmission 3 comprises a continuously engaging gearshift mechanism 25, which consists of a parallel-shaft gear mechanism, a clutch 26 as a power transmission mechanism, which consists of a dry clutch of the normally closed type, a differential mechanism 27, and an actuator (not shown).

[0017] The transmission 3 is designed as an AMT (Automated Manual Transmission), whereby the shifting of a gear position in the gearshift mechanism 25 and the engagement and disengagement of the clutch 26 are carried out by the actuator under control by the TCM 12. The differential 27 is capable of transmitting the power delivered by the gearshift mechanism 25 to the drive shaft 23.

[0018] The motor generator 4 is coupled to the differential mechanism 27 via a chain 28. The motor generator 4 functions as an electric motor.

[0019] As described above, the hybrid vehicle 1 represents a parallel hybrid system in which both the power of the combustion engine 2 and that of the motor-generator 4 can be used for vehicle propulsion. The hybrid vehicle 1 is suitable for operation with the power of the combustion engine 2 and / or the motor-generator 4.

[0020] The motor-generator 4 also functions as a power generator and is suitable for generating electricity during the operation of the hybrid vehicle 1. It should be noted that the motor-generator 4 only needs to be coupled at any point in a power transmission path from the combustion engine 2 to the drive wheel 5 in order to transmit power, and does not need to be coupled to the differential mechanism 27.

[0021] The hybrid vehicle 1 comprises a first energy storage device 30, a high-voltage unit 34 which includes a second energy storage device 33 as an energy storage section, a high-voltage cable 35 and a low-voltage cable 36.

[0022] The first energy storage device 30 and the second energy storage device 33 each consist of a rechargeable secondary battery. The first energy storage device 30 consists of a lead-acid battery.

[0023] The first energy storage device 30 is a low-voltage battery in which the number of cells and the like are specified such that an output voltage of approximately 12 V is generated. The HCU 10 manages the state of the first energy storage device 30, including its remaining capacity, temperature, and charging and discharging currents.

[0024] The second energy storage device 33 is a high-voltage battery in which the number of cells and the like are specified such that it generates a voltage higher than that of the first energy storage device 30, for example, producing an output voltage of 100 V. The second energy storage device 33 consists, for example, of a lithium-ion battery. A state encompassing a stored amount of current, a temperature, and the charging and discharging currents of the second energy storage device 33 is managed by the BMS 16.

[0025] A general load 37 is provided as an electrical load in the hybrid vehicle 1. The general load 37 is a different electrical load than the starter 21 and the ISG 20.

[0026] The general load 37 is an electrical load that does not require a stable electrical power supply and is used intermittently. The general load 37 includes, for example, a windshield wiper and an electric cooling fan that supplies cooling air to the internal combustion engine 2 (not shown).

[0027] The first energy storage device 30 is connected via the low-voltage cable 36 to the starter 21, the ISG 20 and the general load 37 as an electrical load in order to be able to supply electrical power in this way.

[0028] As described above, the first power storage device 30 is suitable for supplying electrical power to at least the starter 21 and the ISG 20 as a starting device that starts the internal combustion engine 2.

[0029] The high-voltage generator 34 includes, in addition to the second energy storage device 33, an inverter 45, the INVCM 14, and the BMS 16. The high-voltage generator 34 is connected to the motor-generator 4 via the high-voltage cable 35, enabling it to supply electrical power.

[0030] The inverter 45 is suitable for performing a conversion between the alternating current connected to the high-voltage cable 35 and the direct current connected to the second energy storage device 33, under the control of the INVCM 14. For example, the INVCM 14 converts the direct current discharged by the second energy storage device 33 into alternating current using the inverter 45 and supplies the alternating current to the motor generator 4 to power the motor generator 4 for operation.

[0031] The INVCM 14 converts the alternating current generated by the motor generator 4 into direct current using the inverter 45 and charges the second energy storage device 33 so that the motor generator 4 can regenerate electrical power.

[0032] The HCU 10, the ECM 11, the TCM 12, the ISGCM 13, the INVCM 14 and the BMS 16 each consist of a computer unit comprising a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory in which backup data and the like are stored, an input port and an output port.

[0033] In the ROM of each computer unit, a program is stored that causes the computer unit to function as HCU 10, ECM 11, TCM 12, ISGCM 13, INVCM 14 or BMS 16, along with various types of constants, different types of maps and the like.

[0034] This means that each CPU executes the program stored in ROM, using RAM as its working area. In this configuration, the computing units according to the present embodiment function as HCU 10, ECM 11, TCM 12, ISGCM 13, INVCM 14 and BMS 16.

[0035] In the present embodiment, the ECM 11 is suitable for implementing the idle-stop control. In the idle-stop control, the ECM 11 is suitable for stopping the internal combustion engine 2 when a predefined stop condition is met, and for restarting the internal combustion engine 2 by controlling the ISG 20 via the ISGCM 13 when a predefined restart condition is met. This prevents unnecessary idling of the internal combustion engine 2 and enables an improvement in the fuel consumption of the hybrid vehicle 1.

[0036] The hybrid vehicle 1 is equipped with CAN communication lines 48 and 49 to form an in-vehicle LAN (Local Area Network) that conforms to a standard such as the CAN (Controller Area Network) standard.

[0037] The HCU 10 is connected to the INVCM 14 and the BMS 16 via CAN communication line 48. The HCU 10, the INVCM 14, and the BMS 16 send and receive signals, such as control signals, to and from each other via CAN communication line 48.

[0038] The HCU 10 is connected to the ECM 11, the TCM 12, and the ISGCM 13 via CAN communication line 49. The HCU 10, the ECM 11, the TCM 12, and the ISGCM 13 send and receive signals, such as control signals, to and from each other via CAN communication line 49.

[0039] Various types of sensors, such as a speed sensor 51, an accelerator pedal position sensor 52 and a clutch stroke sensor 53, are connected to the input port of the HCU 10.

[0040] The speed sensor 51 detects the speed of the hybrid vehicle 1 based on the rotational speed of the drive shaft 23 and the like. The accelerator pedal position sensor 52 detects the accelerator pedal position, i.e., the amount by which an accelerator pedal (not shown) is depressed. The clutch stroke sensor 53 detects the degree of engagement of the clutch 26.

[0041] The HCU 10 is capable of implementing an auxiliary torque output control that outputs an auxiliary torque from the motor generator 4 to the drive wheel 5 while the clutch 26 is disengaged at the time of gear shifting. The expression "while the clutch 26 is disengaged" refers to a period (hereinafter referred to as the "incomplete engagement period") during which the clutch 26 is not fully engaged, and the incomplete engagement period includes a period during which the clutch 26 is in a so-called half-engaged state. The half-engaged state refers to a condition in which the friction materials of the clutch 26 are in slipping engagement for the transmission of power.

[0042] In a vehicle where a clutch is used in the power transmission path between a gearshift mechanism and an internal combustion engine, a so-called torque loss can occur because the engine's torque is not transmitted to a drive wheel during an incomplete clutch engagement period at the time of gear shifting. This torque loss manifests as a loss of acceleration sensation and a deceleration. It can also create a feeling of idling.

[0043] The auxiliary torque output control avoids the creation of a feeling of idling due to a loss of torque by outputting an auxiliary torque from the motor generator 4 to the drive wheel 5 during an incomplete engagement period of the clutch 26 at the time of gear shifting.

[0044] The HCU 10 does not perform the auxiliary torque output control if the amount of current stored in the second current storage device 33 is less than a predetermined amount of stored current.

[0045] If the amount of current stored in the second energy storage device 33 is not less than the predetermined amount of stored current and the auxiliary torque output control is to be performed, the HCU 10 sets a higher disengagement speed of the clutch 26 at the time of gear shifting than in a case where the amount of current stored in the second energy storage device 33 is less than the predetermined amount of stored current.

[0046] The HCU 10 sets the disengagement speed of the clutch 26 to a first speed at the beginning of the shifting process. After a predetermined amount of auxiliary torque has been delivered from the motor-generator 4 to the drive wheel 5, the HCU 10 changes the disengagement speed of the clutch 26 to a second speed, which is higher than the first speed. The HCU 10 sets the prescribed amount in accordance with the amount of current stored in the second energy storage device 33 at the beginning of the shifting process. The HCU 10 sets the prescribed amount so that the amount of current stored in the second energy storage device 33 does not become too low.

[0047] The prescribed amount of auxiliary torque can be adjusted, taking into account the temperature of the second energy storage device 33, in addition to the amount of current stored in the second energy storage device 33. The amount of current drawn from the second energy storage device 33 decreases when the temperature is low. In this case, the amount of torque output by the motor-generator 4 also decreases. Therefore, the prescribed amount is adjusted so that the amount of current stored in the second energy storage device 33 does not become too low.

[0048] The HCU 10 assumes an even higher speed than the second speed when a driver requests a performance improvement. For example, if the amount of accelerator pedal depressed from a point a predetermined time before the start of the shift until the start of the shift, or the amount of the increase in accelerator pedal depressed over time, is not less than a predetermined value, the HCU 10 determines that the driver has requested a performance improvement.

[0049] The HCU 10 also determines when a driver has requested a performance enhancement mode, for example, when the driver selects a performance enhancement mode as the current operating mode. A performance enhancement mode is an operating mode in which the vehicle's driving performance is higher than usual. Examples of performance enhancement modes include Sport mode, Performance mode, and Manual Shift mode. These modes are all suitable for sporty driving.

[0050] If the driver requests a performance improvement, the HCU 10 sets a higher clutch engagement speed 26 at the time of the shift than in a case where the driver does not request a performance improvement. It should be noted that the increase in clutch engagement speed 26 can be reversed if the driver withdraws the performance improvement request during the shift.

[0051] The following is an overview of the control of the engagement and disengagement speed of clutch 26. As in Fig. As shown in Figure 2, if the auxiliary torque output control is not to be performed, the clutch 26 is disengaged at the first speed and the clutch 26 is engaged at a third speed after completion of the shifting operation processing, which is represented by a continuous line A.

[0052] When the auxiliary torque output control is to be performed, the clutch 26 is initially disengaged at the first speed, and the disengagement speed of the clutch 26 is changed to the second speed, which is higher than the first speed, at time t0 when the prescribed amount of auxiliary torque is output from the motor generator 4 to the drive wheel 5, as represented by a solid line B. Subsequently, after completion of the shift operation processing, the clutch 26 is engaged at the third speed.

[0053] If the auxiliary torque output control is to be performed and the driver requests improved performance, the disengagement speed of the clutch 26 at time t0 is set even higher than the second speed when the required amount of auxiliary torque is output from the motor generator 4 to the drive wheel 5, as shown by a dashed line. Additionally, the engagement speed of the clutch 26 is set higher than the third speed after completion of the shift operation processing.

[0054] The driving performance of the hybrid vehicle 1 can thus be ensured by shortening the time required for the gear shift. By shortening the shift time, the torque application time of the motor-generator 4 at the time of gear change can be reduced, and power consumption can be lowered. It should be noted that the time required for processing the gear shift is always the same time period Tc.

[0055] The following describes a clutch control process by the control unit according to the present embodiment, which is configured in the manner described above, with reference to Fig. 3 described. It should be noted that the clutch control process described below is started when the HCU 10 starts operating and is executed at predefined time intervals.

[0056] In step S1, the HCU 10 detects the amount of electricity stored in the second electricity storage device 33.

[0057] In step S2, the HCU 10 determines whether a switching operation should be performed. The HCU 10 uses factors such as vehicle speed, combustion engine speed, and similar parameters to determine whether a switching operation should be performed. If it is determined that a switching operation should not be performed, the HCU 10 terminates the process.

[0058] When it is determined that a switching operation is to be performed, the HCU 10 calculates from the stored current of the second current storage device 33 the prescribed amount, i.e. the amount of motor torque that must be added from the motor generator 4 to the drive wheel 5 in step S3.

[0059] In step S4, the HCU 10 begins to release the clutch 26 at the first speed.

[0060] In step S5, the HCU 10 determines whether the motor torque from motor generator 4 has reached the prescribed value. If it is determined that the motor torque from motor generator 4 has not reached the prescribed value, the HCU 10 repeats the process in step S5.

[0061] When it is determined that the motor torque from the motor generator 4 has reached the prescribed amount, the HCU 10 continues with the disengagement of the clutch 26 at the second speed in step S6.

[0062] In step S7, the HCU 10 determines whether the switching operation processing is complete. If it determines that the switching operation processing is not complete, the HCU 10 repeats the process in step S7.

[0063] When it is determined that the shifting process processing is complete, the HCU 10 performs the engagement of the clutch 26 at the third speed in step S8 and ends the process.

[0064] It should be noted that if the driver requests improved performance, the disengagement and engagement speeds can be set even higher than the second and third speeds. The disengagement and engagement speeds can each be increased by an amount higher than the second and third speeds, which increases with the amount or duration of accelerator pedal input. If the current operating mode requires improved performance, the disengagement and engagement speeds can be set by predetermined amounts higher than the second and third speeds.

[0065] The following describes the operation of the clutch control process described above with reference to the Fig. 4 and Fig. 5 described. Fig. Figure 4 shows a case in which, based on an accelerator pedal actuation amount that is not less than the specified value, it is determined that there is a requirement to improve performance.

[0066] At time t1, the accelerator pedal is pressed. At time t2, if the amount of accelerator pedal pressurization does not fall below the predetermined value, it is determined that a performance improvement request exists.

[0067] At time t3, the disengagement of the clutch 26 begins at the first speed. At time t4, when the motor torque from the motor generator 4 reaches the required amount, the disengagement speed of the clutch 26 is increased to a speed represented by a dashed line, which is higher than the second speed represented by a solid line B, in a case where there is no requirement to improve performance.

[0068] After the clutch 26 has fully disengaged and the shift processing is complete, the clutch 26 begins to engage at a speed represented by the dashed line, which is higher than the third speed represented by the solid line B, in cases where there is no requirement to improve performance. At time t5, the clutch 26 has fully engaged, and the motor torque is no longer supplied by the motor generator 4.

[0069] Fig. Figure 5 shows a case in which, based on the driver's selection of the performance enhancement mode as the current operating mode, it is determined that there is a requirement to improve performance.

[0070] At time t11, the accelerator pedal is pressed. If the driver selects the performance enhancement mode, it is determined that there is a request for performance improvement.

[0071] At time t12, the disengagement of the clutch 26 begins at the first speed. At time t13, when the motor torque from the motor generator 4 reaches the required amount, the disengagement speed of the clutch 26 is increased to a speed represented by a dashed line, which is higher than the second speed represented by a solid line B, in a case where there is no requirement to improve performance.

[0072] After the disengagement of clutch 26 is complete and the shift processing is finished, clutch 26 begins to engage at a speed represented by the dashed line, which is higher than the third speed represented by the solid line B, provided there is no requirement to improve performance. At time t14, clutch 26 is fully engaged, and the motor torque is no longer supplied by the motor generator 4.

[0073] As described above, in the present embodiment, if the amount of current stored in the second energy storage device 33 is not less than the predetermined amount of stored current and the auxiliary torque output control is to be carried out, the disengagement speed of the clutch 26 at the time of switching is set higher than in a case where the amount of current stored in the second energy storage device 33 is less than the predetermined amount of stored current.

[0074] The configuration described above enables a reduction in the time required for the switching process and ensures the driving performance of the hybrid vehicle 1. By reducing the switching time, the period of torque application by the motor generator 4 at the time of switching can be shortened and power consumption reduced.

[0075] The disengagement speed of the clutch 26 at the beginning of the shifting process is set to the first speed. After the prescribed amount of auxiliary torque has been delivered from the motor generator 4 to the drive wheel 5, the disengagement speed of the clutch 26 is changed to the second speed, which is higher than the first speed.

[0076] The configuration described above makes it possible to prevent the occurrence of a so-called torque loss, which refers to a temporary decrease in the torque transmitted to the drive wheel 5 during the switching process.

[0077] The prescribed amount of auxiliary torque is set depending on the amount of current stored in the second energy storage device 33. Since the point in time (a clutch position) at which the disengagement speed of the clutch 26 is increased is set depending on the magnitude of the motor torque that can be delivered given the amount of current stored in the second energy storage device 33, the occurrence of a shift shock can be prevented, torque loss during the shifting process can be avoided, and the shifting time can be shortened. It should be noted that the prescribed amount of auxiliary torque can take into account not only the amount of current stored, but also parameters such as the temperatures of the motor generator 4 and the second energy storage device 33.The lower the temperatures of the motor generator 4 and the second energy storage device 33, the smaller the prescribed auxiliary torque amount of the motor generator 4 is set.

[0078] If the driver requests improved performance, a speed higher than the second speed is adopted. The case where the driver requests improved performance requires rapid acceleration of the hybrid vehicle 1. In this case, the desired driving performance can be achieved by increasing the clutch disengagement speed 26. Since the shift time can be shortened, the time required for torque delivery by the motor-generator 4 can be reduced, thus mitigating the reduction in the amount of current in the second energy storage device 33.

[0079] If the driver requests an improvement in performance, the engagement speed of the clutch 26 at the time of the shifting operation can be set higher than in a case where there is no driver request for an improvement in performance.

[0080] The case in which the driver requires improved performance necessitates rapid acceleration of the hybrid vehicle 1. In this case, a driving performance that better meets the driver's wishes can be achieved by increasing the engagement speed of the clutch 26. Since the shift time can be shortened, the time required for torque delivery by the motor-generator 4 can be reduced, and the reduction in the amount of current in the second energy storage device 33 can be mitigated.

[0081] It should be noted that, although a battery is used as the power storage section in the present embodiment, any device capable of storing electricity can be used. For example, the power storage section could be a capacitor.

[0082] Although a case has been described in which a power transmission mechanism is produced with the coupling 26, anything that is capable of interrupting or allowing the power transmission can be used.

[0083] Although a case has been described in which the coupling 26 is a normally closed coupling, the coupling 26 can be a normally open coupling.

[0084] In a first amendment to the present embodiment, the HCU 10 is set in Fig. 1. The HCU 10 sets the disengagement speed of the clutch 26 to a first speed at the beginning of the shifting process if the stored current in the second energy storage device 33 is not less than a predetermined stored current and auxiliary torque output control is to be performed. When the torque transmitted to the drive wheel 5 becomes equal to the prescribed amount according to the aforementioned embodiment, the HCU 10 changes the disengagement speed of the clutch 26 to a second speed that is higher than the first speed and begins outputting the auxiliary torque from the motor generator 4 to the drive wheel 5. The HCU 10 sets the auxiliary torque to a difference between the prescribed amount and the torque delivered by the internal combustion engine 2 via the transmission 3.

[0085] It should be noted that if the auxiliary torque that can be supplied by the motor generator 4 is not less than the drive torque for the drive wheel 5 at the beginning of the switching process, the clutch 26 can be disengaged at the second speed at the beginning of the switching process and the supply of the auxiliary torque from the motor generator 4 to the drive wheel 5 can be started.

[0086] The HCU 10 assumes an even higher speed than the second speed if a driver requests improved performance according to the aforementioned embodiment.

[0087] When the HCU 10 begins to engage the clutch 26 at the time of the shifting process, the HCU 10 reduces the auxiliary torque transmitted from the motor generator 4 to the drive wheel 5. The HCU 10 sets the auxiliary torque to a difference between the prescribed amount and the torque delivered by the internal combustion engine 2 via the transmission 3.

[0088] If the driver requests improved performance according to the aforementioned embodiment, the HCU 10 sets a higher engagement speed for the clutch 26 at the time of the shifting process than in a case where the driver does not request improved performance. It should be noted that if the driver withdraws the request for improved performance during the shifting process, the increased engagement speed of the clutch 26 can be reversed.

[0089] The following describes a clutch control process by a control unit according to the first amendment of the present embodiment, configured in the manner described above, with reference to Fig. 6 described. It should be noted that the clutch control process described below is started when the HCU 10 starts up and is executed at predefined time intervals.

[0090] As in the embodiment described above, the HCU 10 performs the following processing in steps S1 to S4. The HCU 10 detects the amount of current stored in the second energy storage device 33, determines whether a switching operation is to be performed, calculates from the amount of current stored in the second energy storage device 33 the required amount, i.e., the amount of motor torque that must be added from the motor generator 4 to the drive wheel 5 if it is determined that a switching operation is to be performed, and begins to disengage the clutch 26 at the first disengagement speed.

[0091] In step S11, the HCU 10 determines whether the torque transmitted from the internal combustion engine 2 via the transmission 3 to the drive wheel 5 has reached the prescribed value. If it is determined that the torque transmitted from the internal combustion engine 2 via the transmission 3 to the drive wheel 5 does not have the prescribed value, the HCU 10 repeats the process in step S11.

[0092] When it is determined that the torque transmitted from the internal combustion engine 2 via the transmission 3 to the drive wheel 5 has reached the prescribed amount, the HCU 10 performs the following processing in steps S6 to S8, as in the aforementioned embodiment. The HCU 10 continues the disengagement of the clutch 26 at the second speed, determines, based on the completion of the shifting operation in the transmission 3 with the clutch 26 disengaged, whether the shifting operation processing is complete, engages the clutch 26 at a third speed if it is determined that the shifting operation processing is complete, and terminates the process.

[0093] The sequence of the clutch control process described above is explained with reference to Fig. 7 described. Fig. Figure 7 shows a case where, based on an accelerator pedal actuation amount that is not less than a predetermined value, a requirement for performance improvement is determined. It should be noted that a line labeled K in a clutch state in Fig. 7 indicates the clutch status when the torque transmitted from the internal combustion engine 2 via the transmission 3 to the drive wheel 5 reaches the prescribed amount.

[0094] At time t21, the accelerator pedal is pressed. At time t22, if the amount of accelerator pedal pressed does not fall below the preset value, a request for performance improvement is detected.

[0095] At time t23, the clutch 26 begins to disengage at the first speed. At time t24, when the torque transmitted from the internal combustion engine 2 via the transmission 3 to the drive wheel 5 reaches the specified amount, the disengagement speed of the clutch 26 is increased to a speed represented by a dashed line, which is higher than the second speed represented by a solid line C, provided there is no requirement for increased performance. Simultaneously, the auxiliary torque output from the motor-generator 4 to the drive wheel 5 begins. When the clutch 26 is fully disengaged, the specified amount of auxiliary torque is delivered from the motor-generator 4 to the drive wheel 5.

[0096] After the clutch 26 has fully disengaged and the shift processing is complete, and provided there is no requirement to improve performance, the clutch 26 begins to engage at a speed represented by the dashed line, which is higher than the third speed represented by the solid line C. This reduces the auxiliary torque transmitted from the motor-generator 4 to the drive wheel 5. At time t25, when the torque transmitted from the internal combustion engine 2 via the transmission 3 to the drive wheel 5 reaches the required amount, the motor-generator 4 no longer supplies any engine torque. At time t26, the clutch 26 is fully engaged.

[0097] As described above, in the first modification of the present embodiment, when the auxiliary torque output control is to be carried out, the disengagement speed of the clutch 26 is set to the first speed at the beginning of the shifting process. When the torque transmitted to the drive wheel 5 becomes equal to the aforementioned prescribed amount, the disengagement speed of the clutch 26 is changed to the second speed, which is higher than the first speed, and the delivery of the auxiliary torque from the motor generator 4 to the drive wheel 5 begins.

[0098] In the configuration described above, when the torque transmitted from the internal combustion engine 2 via the transmission 3 to the drive wheel 5 equals the prescribed torque quantity, the disengagement speed of the clutch 26 is increased and an auxiliary torque is supplied by the motor-generator 4. This allows the clutch 26 to disengage earlier and reduces the duration of the shifting process. Furthermore, even if the power source for the torque transmitted to the drive wheel 5 is switched from the internal combustion engine 2 to the motor-generator 4, the change in the torque transmitted to the drive wheel 5 can be limited without generating a torque loss at the drive wheel 5.

[0099] If the driver requests improved performance, a speed even higher than the second speed is adopted. Driving performance that better meets the driver's needs can be achieved by increasing the clutch disengagement speed 26 when the driver requests improved performance. Since the shifting time can be shortened, the torque delivery time of the motor-generator 4 can be reduced, and the loss of electrical energy from the second energy storage device 33 can be limited.

[0100] If the driver requests an improvement in performance, the engagement speed of the clutch 26 at the time of the shifting operation is set higher than in a case where there is no driver request for an improvement in performance.

[0101] Driving performance that better meets the driver's requirements can be achieved by increasing the engagement speed of the clutch 26 when the driver requests improved performance. Since the shift time can be shortened, the torque delivery time of the motor-generator 4 can be reduced, and the loss of electrical energy from the second energy storage device 33 can be limited. It should be noted that a determination that the driver requests improved performance can be made when the driver selects the performance-enhancing mode from a variety of operating mode functions, including the performance-enhancing mode, rather than based on the amount of accelerator pedal input.

[0102] In a second modification of the present embodiment, the HCU 10 is presented in Fig. 1. The HCU 10 sets the disengagement speed of the clutch 26 to a first speed at the beginning of the shifting process if the stored current in the second energy storage device 33 is not less than a predetermined stored current and auxiliary torque output control is to be performed. When the torque transmitted to the drive wheel 5 becomes equal to the prescribed amount according to the aforementioned embodiment, the HCU 10 changes the disengagement speed of the clutch 26 to a second speed that is higher than the first speed and begins outputting the auxiliary torque from the motor generator 4 to the drive wheel 5. The HCU 10 sets the auxiliary torque to a difference between the prescribed amount and the torque delivered by the internal combustion engine 2 via the transmission 3.

[0103] At the time of the shifting process, before the torque transmitted from the internal combustion engine 2 via the transmission 3 to the drive wheel 5 becomes equal to the prescribed amount, the HCU 10 sets an engagement speed of the clutch 26 higher than the speed after the torque transmitted from the internal combustion engine 2 via the transmission 3 to the drive wheel 5 does not become less than the prescribed amount.

[0104] For example, assuming that the engagement speed of the clutch 26 before the torque transmitted from the internal combustion engine 2 via the transmission 3 to the drive wheel 5 becomes equal to the prescribed amount is a fourth speed, and that the engagement speed of the clutch 26 after the torque transmitted from the internal combustion engine 2 via the transmission 3 to the drive wheel 5 becomes no less than the prescribed amount is a fifth speed, then the HCU 10 sets the fourth speed higher than the fifth speed.

[0105] When the clutch 26 begins to engage, the HCU 10 reduces the auxiliary torque transmitted from the motor generator 4 to the drive wheel 5. The HCU 10 sets the auxiliary torque to a difference between the prescribed amount and the torque transmitted from the internal combustion engine 2 via the transmission 3 to the drive wheel 5.

[0106] If a driver requests improved performance according to the aforementioned embodiment, the HCU 10 will assume speeds that are even higher than the fourth and fifth speeds.

[0107] The following describes a clutch control process by a control unit according to the second amendment of the present embodiment, configured in the manner described above, with reference to Fig. 8 described. It should be noted that the clutch control process described below is started when the HCU 10 starts up and is executed at predefined time intervals.

[0108] As in the embodiment described above, the HCU 10 performs the following processing in steps S1 to S4. The HCU 10 detects the amount of current stored in the second energy storage device 33, determines whether a switching operation is to be performed, calculates from the amount of current stored in the second energy storage device 33 the required amount, i.e., the amount of motor torque that must be added from the motor generator 4 to the drive wheel 5 if it is determined that a switching operation is to be performed, and begins to disengage the clutch 26 at the first disengagement speed.

[0109] In step S11, the HCU 10 determines whether the torque transmitted from the internal combustion engine 2 via the transmission 3 to the drive wheel 5 has reached the specified value. If it is determined that the torque transmitted from the internal combustion engine 2 via the transmission 3 to the drive wheel 5 has not reached the specified value, the HCU 10 repeats the process in step S11.

[0110] When it is determined that the torque transmitted from the internal combustion engine 2 via the transmission 3 to the drive wheel 5 has reached the prescribed amount, the HCU 10 performs the following processing in steps S6 and S7 as in the aforementioned embodiment. The HCU 10 continues the disengagement of the clutch 26 at the second speed and determines whether the shifting process processing is complete.

[0111] In step S21, the HCU 10 begins engaging the clutch 26 at the fourth engagement speed.

[0112] In step S22, the HCU 10 determines whether the torque transmitted from the internal combustion engine 2 via the transmission 3 to the drive wheel 5 has reached the prescribed value. If it is determined that the torque transmitted from the internal combustion engine 2 via the transmission 3 to the drive wheel 5 has not reached the prescribed value, the HCU 10 repeats the process in step S22.

[0113] When it is determined that the torque transmitted from the internal combustion engine 2 via the transmission 3 to the drive wheel 5 has reached the prescribed amount, the HCU 10 engages the clutch 26 at the fifth speed in step S23 and ends the process.

[0114] The following describes the sequence of the clutch control process described above, with reference to Fig. 9 described. Fig. Figure 9 shows a case where, based on an accelerator pedal actuation amount that is not less than a predetermined value, a requirement for performance improvement is determined. It should be noted that a line labeled K in a clutch state in Fig. 9 represents the clutch state when the torque transmitted from the internal combustion engine 2 via the transmission 3 to the drive wheel 5 reaches the prescribed amount.

[0115] At time t31, the accelerator pedal is pressed. At time t32, if the amount of accelerator pedal pressed does not fall below the predetermined value, a request for performance improvement is detected.

[0116] At time t33, the disengagement of the clutch 26 begins at the first speed. At time t34, when the torque transmitted from the internal combustion engine 2 via the transmission 3 to the drive wheel 5 reaches the specified amount, the disengagement speed of the clutch 26 is increased to a speed represented by a dashed line, which is higher than the second speed represented by a solid line D, provided there is no requirement for increased performance. Simultaneously, the auxiliary torque from the motor-generator 4 begins to be delivered to the drive wheel 5. When the clutch 26 is fully disengaged, the specified amount of auxiliary torque is delivered from the motor-generator 4 to the drive wheel 5.

[0117] After the clutch 26 has fully disengaged and the shift processing is complete, and provided there is no requirement to improve performance, the clutch 26 engages at the fourth speed (represented by the dashed line), which is higher than the third speed (represented by the solid line D). This reduces the auxiliary torque transmitted from the motor-generator 4 to the drive wheel 5. At time t35, when the torque transmitted from the internal combustion engine 2 to the drive wheel 5 via the transmission 3 reaches the required amount, the motor-generator 4 no longer supplies engine torque. The engagement speed of the clutch 26 changes to the fifth speed, which is lower than the fourth speed. At time t36, the engagement of the clutch 26 is complete.

[0118] As described above, in the second amendment of the present embodiment, when the auxiliary torque output control is to be carried out, the engagement speed of the clutch 26 at the time of the shifting operation, before the torque transmitted from the internal combustion engine 2 via the transmission 3 to the drive wheel 5 becomes equal to the prescribed amount, is set higher than the speed after the torque transmitted from the internal combustion engine 2 via the transmission 3 to the drive wheel 5 does not become less than the prescribed amount.

[0119] With the configuration described above, the engagement speed of the clutch 26 is increased before the torque transmitted from the internal combustion engine 2 via the transmission 3 to the drive wheel 5 corresponds to the prescribed torque value. This allows the clutch 26 to engage earlier and reduces the time from clutch disengagement to completion of engagement. It is also possible to shorten the shifting process and limit the power consumption of the second energy storage device 33.

[0120] When the clutch 26 begins to engage, the auxiliary torque transmitted from the motor generator 4 to the drive wheel 5 is reduced, and a difference between the prescribed amount and the torque transmitted from the internal combustion engine 2 via the transmission 3 to the drive wheel 5 is set as the auxiliary torque.

[0121] With the configuration described above, the auxiliary torque of the motor-generator 4 is reduced at the beginning of clutch engagement 26. When the torque transmitted from the internal combustion engine 2 via the transmission 3 to the drive wheel 5 reaches the prescribed value, the auxiliary torque is no longer supplied. In this way, it is possible to shorten the operating time of the motor-generator 4 during the shifting process and to limit the power consumption of the second energy storage device 33.

[0122] If the driver requests improved performance, a speed higher than the second speed is engaged. Driving performance that better meets the driver's needs can be achieved by increasing the clutch disengagement speed 26 when the driver requests improved performance. Since the shifting time can be shortened, the torque delivery time of the motor-generator 4 can be reduced, and the loss of electrical energy from the second energy storage device 33 can be limited.

[0123] If the driver requests an improvement in performance, the engagement speed of the clutch 26 at the time of the shifting operation is set higher than in a case where there is no driver request for an improvement in performance.

[0124] Driving performance that better meets the driver's requirements can be achieved by increasing the engagement speed of the clutch 26, in cases where the driver requests improved performance. Since the shift time can be shortened, the torque delivery time of the motor-generator 4 can be reduced, and the loss of electrical energy from the second energy storage device 33 can be limited. It should be noted that a determination that a driver requests improved performance can be made when a performance-enhancing mode is selected by the driver from a variety of operating mode functions that include the performance-enhancing mode, rather than based on the amount of accelerator pedal input.

[0125] Although the present embodiment describes an example in which the HCU 10, ECM 11, TCM 12, ISGCM 13, INVCM 14, and BMS 16 perform various types of determinations and calculations based on different types of sensor information, the present invention is not limited thereto. The hybrid vehicle 1 can include a communication section capable of communicating with an external device, such as an external server. The external device can perform various types of determinations and calculations based on information acquired by different types of sensors and transmitted by the communication section. The communication section can receive the results of the determinations and calculations, and various types of control can be performed using the received results of the determinations and calculations.

[0126] The embodiment of the present invention has been disclosed. It is obvious to a person skilled in the art that modifications can be made without departing from the scope of the present invention. It is intended that all such modifications and equivalents are covered by the appended claims. [List of reference symbols] 1 hybrid vehicle 2 Internal combustion engine 3 transmissions (automatic transmission) 4 Motor generator (motor) 5 drive wheel 10 HCU (control section) 16 BMS 25-speed shift mechanism 26 Clutch (power transmission mechanism) 33 Second energy storage device (energy storage section) 51 Speed ​​sensor 52 Accelerator pedal position sensor 53 Clutch stroke sensor

Claims

[1] Control unit for a hybrid vehicle (1), wherein the hybrid vehicle (1) comprises: an internal combustion engine (2) and a motor (4) as drive sources to transmit power to a drive wheel (5); an automatic transmission (3) which changes the speed of the internal combustion engine (2) and transmits the rotation to the drive wheel (5);a power transmission mechanism (26) which forms a disengagement state to interrupt the power transmission between the internal combustion engine (2) and the drive wheel (5), or forms an engagement state to enable the power transmission between the internal combustion engine (2) and the drive wheel (5), and an energy storage device (33) which supplies electrical power to the motor (4), wherein the motor (4) is configured to deliver torque during an incomplete engagement period of the power transmission mechanism (26) when a gear position is shifted in the automatic transmission (3), wherein the control unit comprises the following; a control section (10) which, during gear shifting, changes the disengagement speed of the power transmission mechanism (26) depending on the amount of current stored in the power storage device (33), wherein, if the amount of current stored in the current storage device (33) is not less than a predetermined amount of stored current and auxiliary torque output control is to be performed, the control section (10) sets the disengagement speed higher than in a case where the amount of stored current is less than the predetermined amount of stored current, and wherein the control section (10) changes the disengagement speed from a first speed at the beginning of the shifting process to a second speed which is higher than the first speed, after a prescribed amount of auxiliary torque has been delivered from the motor (4) to the drive wheel (5). [2] Control unit for the hybrid vehicle (1) according to claim 1, wherein the control section (10) changes an engagement speed of the power transmission mechanism (26) during gear shifting in accordance with the amount of current stored in the power storage device (33). [3] Control unit for the hybrid vehicle (1) according to claim 1, wherein the control section (10) sets the prescribed amount depending on the amount of electricity stored in the electricity storage device (33). [4] Control unit for the hybrid vehicle (1) according to one of claims 1 to 3, wherein in a case where the amount of the increase of a depressing amount of the accelerator pedal with respect to time is not less than a predetermined value, the control section (10) sets the second speed higher. [5] Control unit for the hybrid vehicle (1) according to one of claims 1 to 4, wherein in a case where the amount of the increase of a depressing amount of the accelerator pedal with respect to time is not less than a predetermined value, the control section (10) sets the engagement speed of the power transmission mechanism (26) higher.

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