Regenerative control device for hybrid vehicles

Abstract

To provide a hybrid vehicle capable of avoiding shift shock as much as possible while maintaining a regeneration amount when downshifting during regenerative traveling.SOLUTION: A gear-shifting regeneration amount control unit 110 is configured to: make, during downshifting of an automatic transmission 24, a regeneration amount GP regenerated by the electric motor MG smaller than a value GP1 of when other than during downshifting, and equal to or greater than a predetermined required power generation amount GP2; and, in addition, make the regeneration amount GP regenerated by the electric motor MG equal to or less than a predetermined allowable regeneration amount GP3 that does not cause a shock during downshifting. Thereby, a regenerative control device of a hybrid vehicle according to the invention can inhibit deceleration of a vehicle 10 during downshifting from becoming excessively great while maintaining the regeneration amount GP so as to avoid gear-shift shock.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a regeneration control device for a hybrid vehicle that performs regeneration during gear shifting. [Background technology]

[0002] In a hybrid vehicle equipped with an engine and electric motor as a power source for driving, a torque converter and automatic transmission provided between the power source and the drive wheels, and a battery, if the automatic transmission downshifts during regenerative driving in which the battery is being charged with generated power regenerated from the electric motor, it has been proposed to stop power generation by the electric motor and supply the electric power required for driving from the battery to the electric motor, in order to avoid the dragging feeling caused by the downshift, in order to improve drivability.

[0003] However, in a situation where there is a risk of power loss if the electric motor does not generate power during the downshift period, it is necessary to continue generating power by the electric motor. However, in order to prevent negative torque from appearing in the vehicle behavior when the electric motor generates power, it is possible to continue regenerating power by the electric motor only for the necessary amount of power. However, in this case, if regeneration by the electric motor is performed during a downshift, the deceleration due to the regeneration of the electric motor increases, which causes a problem of impaired drivability.

[0004] In response to this, it has been proposed to suppress the loss of deceleration during regenerative running by estimating the transfer torque capacity of the lock-up clutch of the torque converter that is engaged for regeneration of the electric motor so as to obtain the necessary regenerative power while suppressing the deceleration due to regeneration, and increasing the regenerative torque of the electric motor up to a value obtained by adding a margin to the transfer torque capacity, as an upper limit. For example, a hybrid vehicle described in Patent Document 1 is such a system. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2021-109609 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the hybrid vehicle of Patent Document 1, the amount of regeneration of the electric motor is not adjusted in relation to downshifting during regenerative driving, so when downshifting during regeneration, it is difficult to avoid shift shock as much as possible while continuing regeneration.

[0007] The present invention has been made against the background of the above circumstances, and its purpose is to provide a hybrid vehicle that can maintain the amount of regeneration while avoiding shift shock as much as possible when downshifting during regenerative driving. [Means for solving the problem]

[0008] The gist of a first invention is a control device for a hybrid vehicle including (a) an engine and an electric motor as a power source for running, a torque converter and an automatic transmission provided between the power source and drive wheels, and a battery, and (b) a regeneration amount control unit during gear shifting that reduces the amount of regeneration by the electric motor during a downshift of the automatic transmission compared to when the downshift is not being performed. (c) the regeneration amount control unit during gear shifting controls the amount of regeneration by the electric motor during the downshifting to be equal to or less than a predetermined allowable regeneration amount that does not cause a shock during the downshifting and equal to or more than a predetermined required power generation amount that is continued during the gear shifting. The reason is that... [Effects of the Invention]

[0011] According to the control device for a hybrid vehicle of the first invention, the regeneration amount during gear shifting control unit reduces the amount of regeneration by the electric motor during a downshift of the automatic transmission compared to when the downshift is not in progress, thereby maintaining the amount of regeneration and preventing the deceleration of the hybrid vehicle during a downshift from becoming excessively large. Furthermore, the amount of regeneration by the electric motor is set to a predetermined allowable regeneration amount or less that does not cause shock during the downshift. Because reducing the amount of regeneration can change engine friction input to the torque converter and cause shift shock, by setting the amount of regeneration by the electric motor to a predetermined allowable regeneration amount or less, shift shock is avoided. Furthermore, because the amount of regeneration by the electric motor during the downshift is set to a predetermined required amount of power generation that continues during the shift, the required amount of power generation is ensured during the downshift. [Brief explanation of the drawings]

[0014] [Figure 1]1 is a schematic diagram of a hybrid vehicle equipped with an electronic control device as a control device according to an embodiment of the present invention; [Figure 2] 4 is a time chart illustrating the regeneration amount control during a downshift that is functionally included in the electronic control device of FIG. 1. [Figure 3] 3 is a flowchart illustrating the regeneration amount control during a downshift, which is functionally provided in the electronic control device of FIG. 1. [Figure 4] 10 is a time chart illustrating regeneration amount control during a downshift, which is functionally provided in an electronic control device according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0015] The present invention is preferably applied to a hybrid vehicle in which, for example, an electric motor is provided next to an engine and the engine is connected to an automatic transmission via a torque converter, but it can also be applied to a hybrid vehicle in which an electric motor is arranged in series between the engine and the torque converter and an on / off clutch is arranged between the engine and the electric motor. [Example]

[0016] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic diagram of the drive system of a hybrid vehicle 10 (hereinafter simply referred to as vehicle 10) equipped with an electronic control device 100 as a control device that is one embodiment of the present invention, and also shows the control functions for various controls related to vehicle 10 and the main parts of the control system.

[0017] The vehicle 10 is a parallel hybrid vehicle equipped with an engine 12 and an electric motor MG as power sources for running. The engine 12 is an internal combustion engine such as a gasoline engine or a diesel engine, and an engine control device 50 including a throttle actuator, a fuel injection device, an ignition device, etc. is controlled by an electronic control device 100 to control the engine torque Te.

[0018] The electric motor MG is disposed in parallel with the engine 12 and is operatively connected to the crankshaft of the engine 12 via a belt 20. The electric motor MG is a motor generator that functions as both an electric motor and a generator, and is connected to a battery (secondary battery) 54 via an inverter 52. The inverter 52 is controlled by the electronic control device 100, whereby the MG torque Tmg and the MG rotation speed Nmg of the electric motor MG are controlled.

[0019] Battery 54 is a power storage device that supplies power to and receives power from electric motor MG, and is a high-voltage battery that stores electricity at a voltage of several hundred volts. Low-voltage battery 58 is connected to battery 54 via a voltage converter (DC / DC converter) 56. Low-voltage battery 58 is an auxiliary power source for air conditioners, control devices, lighting devices, etc., and stores electricity at a voltage of, for example, 12 V.

[0020] The vehicle 10 includes a power transmission device 16 provided in a power transmission path between an engine 12 and drive wheels 14. The power transmission device 16 includes, in series from the engine 12 side, a torque converter 22 with a lock-up clutch 40 and an automatic transmission 24 within a case 18 attached to the vehicle body. The torque converter 22 is a fluid-type power transmission that transmits power via fluid and is connected to the engine 12. The torque converter 22 includes the lock-up clutch 40 that directly connects input and output rotary members of the torque converter 22. The automatic transmission 24 is, for example, a planetary gear-type stepped transmission with multiple hydraulic engagement devices CB. The power transmission device 16 includes a propeller shaft 28, a differential gear 30, a pair of drive shafts 32, etc.

[0021] The vehicle 10 is equipped with an electronic control unit 100 as a control device that executes various types of control. The electronic control unit 100 is configured to include a so-called microcomputer equipped with, for example, a CPU, RAM, ROM, an input / output interface, etc. The CPU executes various types of control of the vehicle 10 by processing input signals according to programs stored in the ROM in advance while utilizing the temporary storage function of the RAM.

[0022] The electronic control device 100 is supplied with the battery temperature THbat (°C), battery charge / discharge current Ibat (A), and battery voltage Vbat (V) of the battery 54, the engine coolant temperature THwe (°C), and the engine oil temperature THoe (°C) from a battery sensor 84, an engine water temperature sensor 86, and an engine oil temperature sensor 88. The electronic control device 100 is also supplied with various information required for various controls from sensors (not shown), such as the engine rotation speed Ne (rpm), which is the rotation speed of the engine 12, the turbine rotation speed Nt (rpm), which is the same value as the transmission input rotation speed Ni (rpm), the transmission output rotation speed No (rpm) corresponding to the vehicle speed V, the MG rotation speed Nmg (rpm), which is the rotation speed of the electric motor MG, the accelerator opening θacc (%), which is the amount of operation of an accelerator operating member such as an accelerator pedal and indicates the amount of acceleration required by the driver, and the throttle valve opening θth (%), which is the opening of the electronic throttle valve.

[0023] The electronic control unit 100 functionally comprises a power source control unit 102, a driving mode switching control unit 104, a gear change control unit 106, a regeneration control unit 108, etc., in relation to the control of the engine 12 and the electric motor MG.

[0024] The power source control unit 102 calculates a driving demand for the vehicle 10 from the driver, for example, by applying the accelerator opening θacc and the vehicle speed V to a driving demand map. The driving demand is, for example, a required driving torque Trdem at the drive wheels 14. The power source control unit 102 calculates a required input torque Tindem, which is the input torque of the torque converter 22 required to realize the required driving torque Trdem, and controls the engine 12 and the electric motor MG so as to obtain the required input torque Tindem. When the required input torque Tindem is met using at least the output of the engine 12, the power source control unit 102 sets the vehicle to an HEV (Hybrid Electric Vehicle) driving mode. In the HEV driving mode, the vehicle travels using only the engine 12 as a power source, or performs HEV driving using the engine 12 and the electric motor MG as power sources. In this HEV driving mode, the engine torque Te is controlled to realize all or part of the required input torque Tindem, and the MG torque Tmg is controlled to compensate for the torque that is insufficient with the engine torque Te for the required input torque Tindem.

[0025] The driving mode switching control unit 104 controls switching between the BEV driving mode and the HEV driving mode, and basically drives the vehicle in the BEV driving mode. For example, the vehicle drives in the BEV driving mode until the state of charge (SOC) of the battery 54 reaches a predetermined lower limit SOCmin, at which point the vehicle switches to the HEV driving mode. The HEV driving mode is also used under certain conditions, such as in a high-load driving area on a highway. The state of charge (SOC) is a value indicating the state of charge of the battery 54, and is calculated based on, for example, the battery charge / discharge current Ibat and the battery voltage Vbat.

[0026] The shift control unit 106 determines a target gear position of the automatic transmission 24 based on the actual accelerator opening θacc and the vehicle speed V from a pre-stored shift map, and selectively engages the multiple hydraulic engagement devices CB of the automatic transmission 24 so that the actual gear position becomes the target gear position. During coasting, downshifts are performed as the vehicle speed decreases.

[0027] When the vehicle 10 is coasting with the accelerator opening θacc at zero (%) and the battery 54 is ready to accept charge, such as when the remaining charge SOC falls below a predetermined upper limit value SOCmax, the regeneration control unit 108 engages the lock-up clutch 40 to rotate the electric motor MG connected to the drive wheels 14, thereby charging the battery 54 with the power generation amount GP (W) obtained by regeneration of the electric motor MG.

[0028] 2, during a downshift of the automatic transmission 24, the regeneration control unit 108 controls the regeneration amount GP, as indicated by the solid line, to be different from the regeneration amount when no shift is in progress. Prior to the start of the downshift section (inertia phase) of the automatic transmission 24, the in-shift regeneration amount control unit 110 provided in the regeneration control unit 108 reduces the regeneration amount (power generation amount) GP from the regeneration amount GP1 when no shift is in progress at a gentler slope than before, as indicated by the dashed line. When the regeneration amount GP reaches a predetermined required power generation amount GP2 in the latter half of the downshift section, the regeneration amount GP is maintained at the required power generation amount GP2. When the downshift section ends, the regeneration amount GP is returned to the regeneration amount GP1 when no shift is in progress, as indicated by the dashed line. The required power generation amount GP2 is, for example, the expected power consumption of the 12V system of the auxiliary equipment during the downshift.

[0029] In addition, the regeneration amount control unit 110 during gear shifting reduces the regeneration amount GP by the electric motor MG during downshifting of the automatic transmission 24 compared to the value GP1 when downshifting is not in progress, and sets the regeneration amount GP by the electric motor Mg to be equal to or greater than a predetermined required power generation amount GP2 that is to be continued during downshifting.

[0030] 3 is a flowchart illustrating the main control functions of the electronic control unit 100, which is executed during regenerative driving and is initiated when a downshift is requested during regenerative driving. In step S1 (hereinafter, "step" will be omitted) in FIG. 3, the required power generation amount P2 and the timing for reducing the power generation amount GP, which are scheduled for regeneration during the downshift, are calculated, and the reduction of the power generation amount GP is suspended until the calculated target start timing for the reduction. The reduction timing of the power generation amount GP is calculated, for example, based on a delay time experimentally determined in advance from the downshift command.

[0031] When the timing for reducing the power generation amount GP arrives, in S2, prior to the start of the downshift period (inertia phase), the regeneration amount GP begins to decrease at a gentler slope than in the past, as shown by the dashed line in Figure 2. Next, in S3, it is determined whether the decreasing regeneration amount GP has reached a preset required power generation amount P2. If the determination in S3 is negative, S2 and subsequent steps are repeatedly executed.

[0032] If the determination in S3 is affirmative, then in S4, the regeneration amount GP is maintained at the required power generation amount P2 or a value close to it (P2 + α). Next, in S5, it is determined whether the downshift is complete. If the determination in S5 is negative, S4 and subsequent steps are repeatedly executed, and the regeneration amount GP is maintained at the required power generation amount P2 or a value close to it (P2 + α). However, if the determination in S5 is affirmative, then in S6, the regeneration amount GP is increased at a gradient similar to that of the conventional system, as shown by the dashed line in FIG. 2.

[0033] Then, in S7, when the regeneration amount GP reaches the value GP1 when no gear shift is performed, the regeneration amount GP is maintained at the value GP1 when no gear shift is performed.

[0034] As described above, according to the electronic control device 100 of the vehicle 10 of this embodiment, the regeneration amount during shifting control unit 110 reduces the regeneration amount GP by the electric motor MG during downshifting of the automatic transmission 24 compared to the value GP1 when downshifting is not in progress, thereby maintaining the regeneration amount GP and preventing the deceleration of the vehicle 10 during downshifting from becoming excessively large.

[0035] Furthermore, according to the electronic control device 100 of the vehicle 10 of this embodiment, the in-shift regeneration amount control unit 110 sets the regeneration amount GP by the electric motor MG to be equal to or greater than a predetermined required power generation amount GP2 that is to be continued during a downshift of the automatic transmission 24. This ensures the required power generation amount during a downshift.

[0036] Furthermore, according to the electronic control device 100 of the vehicle 10 of this embodiment, the regeneration amount control unit 110 during gear shifting reduces the regeneration amount (power generation amount) GP from the regeneration amount GP1 during non-gear shifting at a gentler slope than conventionally shown by the dashed line prior to the start of the downshifting section (inertia phase) of the automatic transmission 24, and when the power generation amount GP reaches near the predetermined required power generation amount GP2 in the latter half of the downshifting section, the power generation amount GP is maintained in line with the required power generation amount GP2, so that, as shown in Figure 2, the change range ΔNG of the deceleration NG is smaller than the change range ΔNGf of the deceleration NG shown by the conventional dashed line, thereby mitigating gear shift shock. [Example]

[0037] Next, another embodiment of the present invention will be described. In the following description, parts common to the above embodiment will be designated by the same reference numerals and description thereof will be omitted.

[0038] Fig. 4 is a time chart showing another example of the control operation by the during-shift regeneration amount control unit 110. Fig. 4 is basically the same as Fig. 2, but differs in that the allowable power generation amount (regeneration amount) GP3 allowed during a downshift is displayed between the power generation amount GP1 when no shifting is performed and the required power generation amount GP2.

[0039] According to the electronic control device 100 of the vehicle 10 of this embodiment, the in-shift regeneration amount control unit 110 reduces the regeneration amount GP by the electric motor MG compared to the value GP1 when a downshift is not being performed and sets it to equal to or greater than a predetermined required power generation amount GP2, as in the first embodiment, and also sets the regeneration amount GP by the electric motor MG to equal to or less than a predetermined allowable regeneration amount GP3 ​​that does not cause shock during a downshift of the automatic transmission 24. Reducing the regeneration amount can change the engine friction input to the torque converter 22, which can cause a shift shock, so by setting the regeneration amount GP by the electric motor MG to equal to or less than the predetermined allowable regeneration amount GP3, the shift shock can be avoided. [Example]

[0040] In the second embodiment, if the allowable power generation (regeneration) amount GP3 ​​allowed during a downshift is smaller than the power generation amount GP2 required while traveling, allowing the shock could prevent power generation (regeneration) from continuing, which could lead to over-discharge of the battery 54. Therefore, in this embodiment, the allowable power generation (regeneration) amount GP3 ​​allowed during a downshift is compared with the power generation amount GP2 required while traveling, and if the required power generation amount GP2 is greater, deceleration regeneration is stopped and the lock-up clutch 40 of the torque converter 22 is disengaged, thereby ensuring the required power generation amount GP2 while controlling the regeneration (power generation) amount of the electric motor MG so that the negative torque does not cause a shock.

[0041] Although the embodiment of the present invention has been described in detail above with reference to the drawings, this is merely one embodiment, and the present invention can be embodied in various modified and improved forms. [Explanation of symbols]

[0042] 10: Hybrid vehicle 12: Engine 22: Torque converter 24: Automatic transmission 40: Lock-up clutch 54: Battery 100: Electronic control unit (regenerative control unit) 110: Regenerative amount control unit during gear shifting MG: Electric motor

Claims

[Claim 1] A regeneration control device for a hybrid vehicle including an engine and an electric motor as a power source for running, a torque converter and an automatic transmission provided between the power source and drive wheels, and a battery, a regeneration amount control unit during gear shifting that reduces the amount of regeneration by the electric motor during a downshift of the automatic transmission compared to when the downshift is not being performed, The regeneration amount control unit during gear shifting sets the amount of regeneration by the electric motor during the downshift to be equal to or less than a predetermined allowable regeneration amount that does not cause a shock during the downshift and equal to or more than a predetermined required power generation amount that is continued during the gear shift. A regenerative control device for a hybrid vehicle.

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