Speed change control device for hybrid vehicle

Abstract

To provide a speed change control device for a hybrid vehicle that is able to prevent occurrence of torque drop during speed change even when motor torque cannot be output.SOLUTION: A speed change control device for a hybrid vehicle includes: an engine 2; a motor 4; a transmission 3 that performs a speed change for rotation of the engine 2 and transmits it to a drive shaft 11; a clutch 31 that releases or connects power transmission between the engine 2 and the drive shaft 11; and a control unit 8 that executes control such that, when the motor 4 is caused to output torque for a non-complete engagement period of the clutch 31 during the speed change of the transmission 3, and a motor torque limit for limiting the torque output from the motor 4 is generated, the speed change of the transmission 3 is started after the motor torque limit is released by delaying the start of the speed change of the transmission 3.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a gear shift control device for a hybrid vehicle. [Background technology]

[0002] Patent Document 1 describes a motor assist control device for a hybrid vehicle that causes the motor to output assist torque during a period in which the clutch is not fully engaged when the automatic transmission is shifting. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-194990 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when the motor torque cannot be output due to the state of the motor, there is a problem that torque loss occurs during gear shifting.

[0005] SUMMARY OF THE PRESENT DISCLOSURE In view of the above, an object of the present invention is to provide a gear shift control device for a hybrid vehicle that can suppress the occurrence of torque loss during gear shifting even when motor torque cannot be output. [Means for solving the problem]

[0006] In order to solve the above problems, the present invention provides a gear shift control device for a hybrid vehicle which includes an engine, a motor, an automatic transmission which changes the rotation of the engine and transmits it to a drive shaft, and a clutch which disconnects or connects the power transmission between the engine and the drive shaft, and which causes the motor to output torque during a period when the clutch is not fully engaged when the automatic transmission is shifting, and which includes a control unit which, when a motor torque limit which limits the torque output from the motor occurs, delays the start of gear shifting of the automatic transmission and controls the automatic transmission to start gear shifting after the motor torque limit is released. Effect of the Invention

[0007] In this way, according to the present invention, even when motor torque cannot be output, it is possible to prevent torque loss during gear shifting. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram of a hybrid vehicle transmission control device according to one embodiment of the present invention. [Diagram 2] FIG. 2 is a flowchart showing a procedure of a shift control process of the shift control device for a hybrid vehicle according to one embodiment of the present invention. [Diagram 3] FIG. 3 is a time chart showing an example of a change in torque during gear shifting when a short-time motor torque limit occurs due to the gear shift control process of the gear shift control device for a hybrid vehicle according to one embodiment of the present invention. [Figure 4] FIG. 4 is a time chart showing an example of a change in torque during gear shifting when a long-term motor torque limit occurs due to the gear shift control process of the gear shift control device for a hybrid vehicle according to one embodiment of the present invention. [Diagram 5] FIG. 5 is a time chart showing an example of a change in torque during a gear shift when a conventional short-term motor torque limit occurs. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] A shift control device for a hybrid vehicle according to one embodiment of the present invention includes an engine, a motor, an automatic transmission that changes the rotation of the engine and transmits it to the drive shaft, and a clutch that disconnects or connects the power transmission between the engine and the drive shaft, and is a shift control device for a hybrid vehicle that causes the motor to output torque during a period when the clutch is not fully engaged when the automatic transmission is shifting, and is configured to include a control unit that, when a motor torque limit that limits the torque output from the motor occurs, delays the start of shifting of the automatic transmission and controls the automatic transmission to start shifting after the motor torque limit is released.

[0010] As a result, the gear shift control device for a hybrid vehicle according to one embodiment of the present invention can suppress the occurrence of torque loss during gear shifting even when motor torque cannot be output. EXAMPLES

[0011] A hybrid vehicle equipped with a gear change control device according to an embodiment of the present invention will be described in detail below with reference to the drawings.

[0012] In FIG. 1, a hybrid vehicle 1 according to one embodiment of the present invention includes an engine 2 as an internal combustion engine, a transmission 3 as an automatic transmission, a motor 4, an inverter 5, a high-voltage battery 6, a low-voltage battery 7, and a control unit 8.

[0013] A plurality of cylinders are formed in the engine 2. In this embodiment, the engine 2 is configured to perform a series of four strokes, which are an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke, for each cylinder.

[0014] A starting device 21 is connected to the engine 2. The starting device 21 is connected to a crankshaft of the engine 2 via a belt (not shown). When power is supplied to the starting device 21, the starting device 21 rotates to rotate the crankshaft, thereby providing the engine 2 with a rotational force at the time of starting.

[0015] The starting device 21 is composed of a starter and an ISG (Integrated Starter Generator). The starting device 21 may include both a starter and an ISG.

[0016] The transmission 3 changes the speed of the rotation output from the engine 2 and drives the drive wheels 10 via a drive shaft 11. The transmission 3 includes a constant mesh type speed change mechanism (not shown) made of a parallel shaft gear mechanism, and an actuator (not shown).

[0017] A dry single-plate clutch 31 is provided between the engine 2 and the transmission 3, and the clutch 31 connects and disconnects the power transmission between the engine 2 and the transmission 3.

[0018] The transmission 3 is configured as a so-called AMT (Automated Manual Transmission), and an actuator (not shown) switches the gears in the transmission mechanism and engages and disengages the clutch 31.

[0019] A differential mechanism 32 is provided between the transmission 3 and the drive wheels 10. The differential mechanism 32 and the drive wheels 10 are connected by a drive shaft 11.

[0020] The motor 4 is connected to the differential mechanism 32 via a reduction gear (not shown) such as a chain. The motor 4 functions as an electric motor. The motor 4 also functions as a generator, generating electricity when the hybrid vehicle 1 runs.

[0021] The motor 4 is provided with a temperature sensor 41 that detects the temperature of the motor 4. The temperature sensor 41 is connected to the control unit 8.

[0022] Under the control of the control unit 8, the inverter 5 converts DC power supplied from a high-voltage battery 6 or the like into three-phase AC power and supplies it to the motor 4.

[0023] The inverter 5 converts the three-phase AC power generated by the motor 4 into DC power under the control of the control unit 8. This DC power charges the high-voltage battery 6, for example.

[0024] The high-voltage battery 6 is, for example, a lithium-ion battery. The high-voltage battery 6 supplies power to the inverter 5.

[0025] The high-voltage battery 6 is provided with a battery state sensor 61. The battery state sensor 61 detects the charge / discharge current, voltage, and battery temperature of the high-voltage battery 6. The battery state sensor 61 is connected to the control unit 8. The control unit 8 is capable of detecting the charge amount of the high-voltage battery 6 from the output of the battery state sensor 61.

[0026] The low-voltage battery 7 is, for example, a lead battery, and supplies electric power to the electric loads of the hybrid vehicle 1, such as the starting device 21.

[0027] In this way, the hybrid vehicle 1 constitutes a parallel hybrid system capable of using the power of both the engine 2 and the motor 4 to drive the vehicle, and is configured to run using the power output by at least one of the engine 2 and the motor 4.

[0028] The control unit 8 is composed of a computer unit equipped with a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory for storing backup data, etc., an input port, and an output port.

[0029] The ROM of this computer unit stores a program for causing the computer unit to function as the control unit 8, together with various constants and various maps.

[0030] That is, the CPU executes the programs stored in the ROM using the RAM as a working area, and these computer units function as the control unit 8 in this embodiment.

[0031] To an input port of the control unit 8, various sensors including the above-mentioned temperature sensor 41 and battery state sensor 61, as well as an accelerator opening sensor 81 and a clutch stroke sensor 82 are connected.

[0032] The accelerator opening sensor 81 detects the amount of operation of an accelerator pedal (not shown) as the accelerator opening. The clutch stroke sensor 82 detects the degree of engagement of the clutch 31.

[0033] On the other hand, an output port of the control unit 8 is connected to various control targets including the above-mentioned starting device 21, the actuator of the transmission 3, the inverter 5, and an injector (not shown).

[0034] In this embodiment, the control unit 8 calculates a driver requested torque based on the accelerator opening degree, etc. The control unit 8 controls the engine 2, the transmission 3, the clutch 31, and the motor 4 so that the driver requested torque is output to the driving wheels 10.

[0035] Furthermore, in the shift control for controlling the switching of the gear stages of the speed change mechanism of the transmission 3, the control unit 8 executes assist torque output control for outputting assist torque from the motor 4 to the drive wheels 10 while the clutch 31 is disengaged during shifting. "While the clutch 31 is disengaged" refers to the period during which the clutch 31 is not fully engaged (hereinafter, this period will be referred to as the "non-engagement period"), and the non-engagement period includes a so-called half-clutch state. The half-clutch state refers to a state in which the friction materials of the clutch 31 are engaged in a slipping state to transmit power.

[0036] In vehicles that have a clutch installed in the power transmission path between the transmission and the engine, when the clutch is not fully engaged during a gear change, torque from the engine is not transmitted to the drive wheels, resulting in a loss of feeling of acceleration / deceleration, or a so-called torque loss. This torque loss creates a feeling of freewheeling.

[0037] The assist torque output control is to prevent the occurrence of a feeling of free running due to torque loss by outputting an assist torque from the motor 4 to the drive wheels 10 while the clutch 31 is not fully engaged during gear shifting.

[0038] When a motor torque limit that limits the torque output from the motor 4 occurs, the control unit 8 delays the start of the gear shift and starts the gear shift after the motor torque limit is released.

[0039] The motor torque restriction includes not only a state in which no motor torque can be output at all, but also a state in which no motor torque equal to or greater than a predetermined value can be output.

[0040] The motor torque limit includes a short-term motor torque limit, in which the torque output from the motor 4 is limited for a short period of time, and a long-term motor torque limit, in which the torque output from the motor 4 is limited for a long period of time.

[0041] The short-term motor torque limitation is, for example, a motor torque limitation that is imposed when it is determined that a motor lock of the motor 4 has occurred.

[0042] Motor lock occurs when the motor 4 outputs torque without rotating, causing the phase current to concentrate at one pole, generating heat and preventing the motor 4 from continuously outputting torque.

[0043] For example, when the hybrid vehicle 1 starts moving, motor torque is output by the assist torque output control, but if the motor rotation speed does not increase due to a slope or a step, the motor lock occurs.

[0044] When the motor torque limit is applied for a short time, the control unit 8 delays the start of the gear shift, and starts the gear shift after the motor torque limit is released.

[0045] When the motor torque restriction has been occurring for a long period of time, the control unit 8 starts the gear shift without delaying the start of the gear shift.

[0046] When the motor torque restriction is released for a long period during a non-complete engagement period of the clutch 31 during gear shifting, the control unit 8 maintains a state in which no torque is output from the motor 4 during this non-complete engagement period.

[0047] The shift control process performed by the shift control device according to this embodiment configured as above will be described with reference to Fig. 2. The shift control process described below starts when the control unit 8 starts operating, and is executed at preset time intervals.

[0048] In step S1, the control unit 8 determines whether or not there is a gear shift request. If it is determined that there is a gear shift request, the control unit 8 executes the process of step S2. If it is determined that there is no gear shift request, the control unit 8 ends the gear shift control process.

[0049] In step S2, the control unit 8 determines whether or not a short-term motor torque limit is occurring.

[0050] If it is determined that the short-term motor torque limit is occurring, the control unit 8 executes the process of step S3. If it is determined that the short-term motor torque limit is not occurring, the control unit 8 executes the process of step S5.

[0051] In step S3, the control unit 8 determines whether or not the short-time motor torque limit has been released.

[0052] If it is determined that the short-term motor torque limit has been released, the control unit 8 executes the process of step S4. If it is determined that the short-term motor torque limit has not been released, the control unit 8 executes the process of step S3.

[0053] In step S4, the control unit 8 performs normal gear shift control accompanied by assist torque output control. After executing the process of step S4, the control unit 8 ends the gear shift control process.

[0054] In step S5, the control unit 8 determines whether or not a long-term motor torque restriction has occurred.

[0055] If it is determined that the long-term motor torque limit has occurred, the control unit 8 executes the process of step S6. If it is determined that the long-term motor torque limit has not occurred, the control unit 8 executes the process of step S7.

[0056] In step S6, the control unit 8 performs gear shift control without outputting motor torque. After executing the process of step S6, the control unit 8 ends the gear shift control process.

[0057] In step S7, the control unit 8 performs normal gear shift control accompanied by assist torque output control. After executing the process of step S7, the control unit 8 ends the gear shift control process.

[0058] The operation of such a gear shift control process will be described with reference to Figures 3 to 5. Figures 3 to 5 show the operation of the hybrid vehicle 1 when it starts moving.

[0059] As shown in FIG. 5, in conventional gear shift control, when hybrid vehicle 1 starts to move and short-time motor torque limitation occurs at time t21, motor torque is not output.

[0060] When a gear shift request occurs at time t22, the clutch 31 begins to release, and if the torque of the motor 4 can be output, the torque of the motor 4 increases to compensate for the torque of the engine 2, as shown by the dotted line. However, because the motor torque is limited for a short period of time, the torque of the motor 4 cannot be output, and a gear shift shock occurs.

[0061] At time t23, the motor torque limit is released for a short time, and if torque is immediately output from the motor 4, a further shock will occur.

[0062] In this embodiment, as shown in FIG. 3, when the hybrid vehicle 1 starts to move, a short-term motor torque limit occurs at time t1, and even if a gear shift request occurs at time t2, the start of the gear shift is delayed until time t3 when the short-term motor torque limit is released.

[0063] The gear shift starts from time t3, the clutch 31 starts to be released, and torque is output from the motor 4 to supplement the torque of the engine 2. When the gear shifting of the speed change mechanism of the transmission 3 is completed, the clutch 31 starts to be engaged and the torque of the motor 4 is reduced in synchronization with the increase in the torque of the engine 2, and the gear shift is completed at time t4.

[0064] In this embodiment, when long-term motor torque limitation occurs, as shown in Figure 4, when the hybrid vehicle 1 begins to move, the long-term motor torque limitation occurs at time t11, and a gear shift request occurs at time t12, no motor torque is output.

[0065] The gear shift starts from time t12, and is carried out without the motor 4 outputting any torque.

[0066] Even if the long-time motor torque limit is released at time t13, the state in which no torque is output from the motor 4 is maintained during the non-complete engagement period of the clutch 31 until time t14, and the gear shift is completed at time t14.

[0067] Thus, in this embodiment, when a motor torque limit that limits the torque output from the motor 4 occurs, the control unit 8 delays the start of gear shifting and starts gear shifting after the motor torque limit is released.

[0068] As a result, when the motor torque limit is occurring, the start of the gear shift is delayed and the gear shift is started after the motor torque limit is released, thereby making it possible to suppress the occurrence of torque loss during the gear shift.

[0069] In addition, when a motor torque limit has occurred for a short period of time, the control unit 8 delays the start of the gear shift and starts the gear shift after the motor torque limit has been released, and when a motor torque limit has occurred for a long period of time, the control unit 8 starts the gear shift without delaying the start of the gear shift.

[0070] As a result, when a short-term motor torque limit is applied, the start of gear shifting is delayed and gear shifting begins after the short-term motor torque limit is released, thereby making it possible to suppress torque loss during gear shifting.

[0071] When the motor torque is limited for a long period of time, the gear shift is performed without delaying the start of the gear shift, so that deterioration of drivability due to a gear shift delay can be suppressed.

[0072] Furthermore, when the motor torque restriction is released for a long period of time during which the clutch 31 is not fully engaged when shifting gears, the control unit 8 maintains a state in which no torque is output from the motor 4 during this period of not fully engaged gears.

[0073] As a result, if the motor torque limit is released for a long period of time during which the clutch 31 is not fully engaged during gear shifting, a state in which no torque is output from the motor 4 is maintained, thereby reducing the occurrence of shock caused by the sudden output of motor torque during gear shifting.

[0074] In this embodiment, an example has been described in which the control unit 8 performs various determinations and calculations based on various sensor information, but this is not limited thereto. The hybrid vehicle 1 may be provided with a communication unit capable of communicating with an external device such as an external server, and various determinations and calculations may be performed by the external device based on the detection information of the various sensors transmitted from the communication unit. The determination results and calculation results may be received by the communication unit, and various controls may be performed using the received determination results and calculation results.

[0075] Although an embodiment of the invention has been disclosed, it will be apparent to one of ordinary skill in the art that modifications may be made thereto without departing from the spirit and scope of the invention, and it is intended that all such modifications and equivalents be included in the following claims. [Explanation of symbols]

[0076] 1 Hybrid vehicles 2 Engine 3 Transmission (automatic transmission) 4 Motor 8. Control Unit 11 Drive shaft 31 Clutch 82 Clutch stroke sensor

Claims

1. A shift control device for a hybrid vehicle including an engine, a motor, an automatic transmission that changes the speed of rotation of the engine and transmits the rotation to a drive shaft, and a clutch that connects or disconnects power transmission between the engine and the drive shaft, the shift control device causing the motor to output torque during a period when the clutch is not fully engaged during a shift of the automatic transmission, A shift control device for a hybrid vehicle that includes a control unit that, when a motor torque limit that limits the torque output from the motor occurs, delays the start of shifting of the automatic transmission so that the automatic transmission starts shifting after the motor torque limit is released.

2. The motor torque limit includes a short-term motor torque limit, which is a time period during which the torque output from the motor is limited, and a long-term motor torque limit, which is a time period during which the torque output from the motor is limited, 2. The shift control device for a hybrid vehicle according to claim 1, wherein, when the short-term motor torque limit has occurred, the control unit controls the automatic transmission to start shifting by delaying the start of shifting and to start shifting after the short-term motor torque limit has been released, and, when the long-term motor torque limit has occurred, the control unit controls the automatic transmission to start shifting without delaying the start of shifting.

3. 3. The shift control device for a hybrid vehicle according to claim 2, wherein the short-term motor torque limit is set when it is determined that a motor lock has occurred in the motor.

4. 4. The shift control device for a hybrid vehicle according to claim 2 or 3, wherein when the long-term motor torque limit is released during a non-complete engagement period of the clutch when the automatic transmission is shifting, the control unit maintains a state in which no torque is output from the motor during the non-complete engagement period.

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