Control method of vehicle and control device of vehicle

Abstract

If the vehicle speed reaches a first speed threshold value (V1) that varies depending on the deceleration of the vehicle while deceleration running, the control unit (21) disengages the lock-up clutch (3a). In addition, if the vehicle speed reaches a second speed threshold value (V2) that varies depending on the deceleration of the vehicle while deceleration running, the control unit (21) ends the regenerative power generation by the alternator (11). Thus, the vehicle can set the timing of ending the regenerative power generation by the alternator (11) while deceleration running depending on the deceleration of the vehicle, and can take into account both the fuel consumption performance and the operation performance.

Description

Technical Field

[0001] This invention relates to a vehicle control method and a vehicle control device. Background Technology

[0002] For example, Patent Document 1 discloses a technique in which coasting regeneration control is performed to generate regenerative torque from an electric generator during deceleration. In Patent Document 1, if the vehicle speed decreases to the coasting end speed when this coasting regeneration control is executed, the coasting regeneration force is set to "0".

[0003] Sometimes, during deceleration, the lock-up clutch engages to cut off fuel supply while simultaneously generating electricity through regeneration. If the vehicle speed reaches a predetermined speed based on the deceleration, the engaged lock-up clutch disengages. Consequently, the timing of the cessation of regeneration and the disengagement of the lock-up clutch sometimes overlaps due to deceleration, causing the deceleration to disappear abruptly and leading to deterioration in operational performance.

[0004] That is, when regenerative power generation is implemented while driving at reduced speed, there is room for further improvement in terms of balancing operational performance and fuel consumption.

[0005] Patent Document 1: International Publication No. 2018 / 189897 Summary of the Invention

[0006] Regarding the vehicle of the present invention, when decelerating, if the vehicle speed reaches a first vehicle speed set according to the vehicle's deceleration, the lock-up clutch is disengaged; if the vehicle speed reaches a second vehicle speed different from the first vehicle speed, the regenerative power generation using the alternator is terminated.

[0007] According to the present invention, both fuel consumption performance and operational performance can be taken into account. Attached Figure Description

[0008] Figure 1 This is a schematic diagram illustrating a general outline of the system structure of a vehicle to which the present invention is applied.

[0009] Figure 2 This is a comparative timing diagram illustrating an example of the operation when regenerative power generation has ceased.

[0010] Figure 3 This is a timing diagram illustrating an example of the action when a first speed threshold V1 and a second speed threshold V2 are set based on the vehicle's deceleration.

[0011] Figure 4 This is a flowchart illustrating an example of the control process during deceleration. Detailed Implementation

[0012] An embodiment of the present invention will now be described in detail with reference to the accompanying drawings. Figure 1 This is a schematic diagram illustrating a general outline of the system structure of a vehicle to which the present invention is applied.

[0013] The internal combustion engine 1 is, for example, a multi-cylinder spark-ignition gasoline internal combustion engine, installed in vehicles such as automobiles. The internal combustion engine 1 has a fuel injection valve (not shown). The fuel injection quantity, fuel injection timing, and fuel pressure supplied to the fuel injection valve are optimally controlled by the control unit 21, which will be described later.

[0014] The driving force of the internal combustion engine 1 is transmitted to the CVT (continuously variable transmission) 5, which is a transmission, via the torque converter 3 and the feedforward clutch 4. The driving force transmitted to the CVT 5 is transmitted to the vehicle's drive wheels 7 via the final gear 6.

[0015] That is, the internal combustion engine 1 transmits the rotation of a crankshaft (not shown) as driving force to the vehicle's drive wheels 7.

[0016] Additionally, the torque converter 3, which includes a pump impeller and a turbine rotor (not shown), has a mechanical lock-up clutch 3a that engages / disengages the pump impeller and turbine rotor. The engagement / disengagement of the lock-up clutch 3a is controlled based on various operating conditions such as vehicle speed and accelerator pedal opening. For example, the lock-up clutch 3a is disengaged during initial acceleration and engaged during stable driving or deceleration.

[0017] The feedforward clutch 4 is located between the torque converter 3 and the CVT 5, and engages when the drive torque from the internal combustion engine 1 can be transmitted to the drive wheel 7. That is, the feedforward clutch 4 is configured on the power transmission path that transmits the drive force of the internal combustion engine 1 to the drive wheel 7. Furthermore, the engagement / disengagement of the lock-up clutch 3 and the feedforward clutch 4 are performed based on control commands from the control unit 21 described later.

[0018] The CVT5 has a primary pulley 8 on the input side, a secondary pulley 9 on the output side, and a conveyor belt 10 that transmits the rotation of the primary pulley 8 to the secondary pulley 9.

[0019] For example, CVT5 uses hydraulic pressure to change the width of the V-groove (not shown) of the primary pulley 8 and secondary pulley 9 around which the conveyor belt 10 is attached, thereby changing the contact radius between the conveyor belt 10 and the primary pulley 8 and secondary pulley 9, and thus changing the speed ratio steplessly.

[0020] Furthermore, while CVT5 can be used as a transmission, a stepped automatic transmission can also be used instead. In this case, the feedforward clutch 4 is configured to utilize multiple friction engagement elements found in a stepped automatic transmission.

[0021] In addition, the internal combustion engine 1 drives the alternator 11, which generates electricity to charge the vehicle battery (not shown), the compressor 12 of the air conditioner (air conditioner), etc.

[0022] The alternator 11 and compressor 12 are located closer to the internal combustion engine 1 than the torque converter 3, and can be driven by the internal combustion engine 1.

[0023] The rotational force along the aforementioned power transmission path can be transmitted to the alternator 11 and the compressor 12. The rotation from the internal combustion engine 1 and the drive wheel 7 is transmitted to the alternator 11 via the conveyor belt 13. The rotation from the internal combustion engine 1 and the drive wheel 7 is transmitted to the compressor 12 via the conveyor belt 14.

[0024] When there is a drive request for auxiliary equipment such as alternator 11 and compressor 12 and the aforementioned auxiliary equipment is driven, the load of the auxiliary equipment acts on the internal combustion engine 1, and the load of the internal combustion engine 1 increases.

[0025] The control unit 21 receives various sensor signals, including: crankshaft angle sensor 22 (detecting crankshaft angle), accelerator pedal (not shown) depressor position sensor 23 (detecting accelerator pedal depressor position), vehicle speed sensor 24 (detecting vehicle speed), acceleration sensor 25 (detecting vehicle acceleration), brake sensor (brake switch) 26 (detecting brake pedal (not shown) depressor position), air conditioning sensor (air conditioning switch) 27 (detecting air conditioning ON / OFF), and refrigerant pressure sensor 28 (detecting air conditioning refrigerant pressure).

[0026] The control unit 21 is a well-known electronic computer with a CPU, ROM, RAM and input / output interfaces.

[0027] When the vehicle decelerates, the control unit 21 engages the lock-up clutch 3a to generate regenerative power using the alternator 11.

[0028] The crankshaft angle sensor 22 can detect the rotational speed (engine speed) of the internal combustion engine 1. The acceleration sensor 25 can detect the deceleration of the vehicle.

[0029] Figure 2 This is a comparative timing diagram illustrating an example of the operation when regenerative power generation ceases. Figure 2 In the comparative example shown, if the vehicle speed (vehicle speed) is less than or equal to a preset constant value (fixed value), i.e., a specified speed threshold V0, when the vehicle is decelerating, the regenerative power generation using the alternator 11 is stopped.

[0030] exist Figure 2In the comparative example shown, at time t1, the vehicle's speed becomes less than or equal to the speed threshold V0.

[0031] exist Figure 2 In the comparative example shown, the regeneration implementation flag switches from "1" to "0" at time t1. The alternator 11 performs regenerative power generation when the regeneration implementation flag is "1" and does not perform regenerative power generation when the flag is "0". Therefore, the alternator 11 ends regenerative power generation when the regeneration implementation flag switches from "1" to "0" and begins regenerative power generation when the flag switches from "0" to "1".

[0032] exist Figure 2 In the comparative example shown, if the vehicle speed reaches a predetermined speed threshold set according to the vehicle's deceleration, the lock-up clutch 3a disengages. At time t1, the vehicle speed reaches the predetermined speed threshold, causing the lock-up clutch 3a to disengage. The lock-up signal switches from "ON" to "OFF" at time t1. Clutch 4 engages when the lock-up signal is "ON" and disengages when the lock-up signal is "OFF".

[0033] like Figure 2 As shown, if the vehicle speed is less than or equal to a specified constant value, i.e., the speed threshold V0, the regenerative power generation using the alternator 11 will stop. Sometimes the timing of the stop of the regenerative power generation of the alternator 11 and the disengagement of the lock-up clutch 3a overlaps with the deceleration of the vehicle, and the deceleration sensation disappears suddenly, resulting in poor operating performance.

[0034] Therefore, in Figure 2 The comparative examples shown may not be able to balance fuel consumption performance and operational performance.

[0035] Therefore, regarding the control unit 21 of this embodiment, if the vehicle speed becomes less than or equal to the first speed threshold V1 during deceleration, the lock-up clutch 3a is disengaged. Furthermore, regarding the control unit 21, if the vehicle speed becomes less than or equal to a second speed threshold V2 that is different from the first speed threshold V1 during deceleration, regenerative power generation using the alternator 11 is stopped (regardless of conditions, the first speed threshold V1 and the second speed threshold V2 are always different). The first speed threshold V1 corresponds to the first vehicle speed and varies according to the vehicle's deceleration. The second speed threshold V2 corresponds to the second vehicle speed and varies according to the vehicle's deceleration.

[0036] That is, regarding the control unit 21, which is equivalent to the control unit, if the vehicle speed reaches the first speed threshold V1 when decelerating, the lock-up clutch 3a is disengaged; if the vehicle speed reaches the second speed threshold V2 when decelerating, the regenerative power generation using the alternator 11 is terminated.

[0037] Therefore, the vehicle in this embodiment can set the regenerative power generation shutdown time of the alternator 11 when decelerating according to the vehicle's deceleration speed, thus balancing fuel consumption performance and operational performance.

[0038] Furthermore, when the deceleration is small, the second speed threshold V2 can be set lower to improve fuel consumption. When the deceleration is large, the second speed threshold V2 can be set higher than the first speed threshold V1 to prevent engine stalling.

[0039] The greater the vehicle's deceleration, the higher the first speed threshold V1 or the second speed threshold V2 should be set.

[0040] Therefore, when the deceleration is large, the first speed threshold V1 or the second speed threshold V2 can be set higher in order to prevent the engine from stalling.

[0041] Furthermore, the first speed threshold V1 and the second speed threshold V2 can be set in such a way that the greater the vehicle's deceleration, the higher both become.

[0042] Figure 3 This is a timing diagram illustrating an example of the action when a first speed threshold V1 and a second speed threshold V2 are set based on the vehicle's deceleration.

[0043] Figure 3 The first velocity threshold V1, indicated by the dashed line, is set to be the same as... Figure 3 The second speed threshold V2 is represented by a dashed line, indicating different values. That is, when the vehicle deceleration is the same, the first speed threshold V1 and the second speed threshold V2 are set to different values.

[0044] exist Figure 3 In the embodiment shown, Figure 3 If the vehicle speed, indicated by the solid line, is less than or equal to the second speed threshold V2 at time t1, the regeneration implementation flag switches from "1" to "0" at time t1.

[0045] In addition, Figure 3 In the embodiment shown, Figure 3 The vehicle speed, indicated by the solid line, is less than or equal to the first speed threshold V1 at time t2, and the locking signal switches from "ON" to "OFF" at time t2. Furthermore, the threshold value for the locking signal to switch from "OFF" to "ON" is set to be greater than the first speed threshold V1. Therefore, in Figure 3 In this case, the lockout signal remains in the "OFF" state after time t2.

[0046] The control unit 21 can be configured such that the end of regenerative power generation of the alternator 11 occurs before the disengagement of the lock-up clutch 3a. That is, the first speed threshold V1 can be set to be less than the second speed threshold V2.

[0047] In this case, when the vehicle decelerates, the regenerative power generation of the alternator 11 can be stopped before the lock-up clutch 3a is disengaged. The timing of the stop of the regenerative power generation of the alternator 11 and the disengagement of the lock-up clutch 3a will not overlap, thus suppressing the deterioration of operating performance.

[0048] The control unit 21 can be configured such that the lock-up clutch 3a disengages earlier than the end of regenerative power generation of the alternator 11. That is, the first speed threshold V1 can be set to be greater than the second speed threshold V2.

[0049] In this case, when the vehicle deceleration is small (slow deceleration), the second speed threshold V2 that causes the regenerative power generation of the alternator 11 to end can be set lower in order to improve fuel consumption.

[0050] The first speed threshold V1 and the second speed threshold V2 can be set in such a way that the higher the refrigerant pressure of the air conditioner, the higher the load on the internal combustion engine 1.

[0051] This prevents the internal combustion engine 1 from stalling when decelerating.

[0052] The first speed threshold V1 and the second speed threshold V2 can be changed when the brake is engaged and when the brake is disengaged.

[0053] For example, when the brake is engaged, the deceleration is changed according to the operator's wishes, so even if the first speed threshold V1 and the second speed threshold V2 are set to the lower side compared to the case where the brake is disengaged, the operator will not feel any disharmony and the operating performance can be ensured.

[0054] For example, when the brake is off, the first speed threshold V1 and the second speed threshold V2 are set to the higher side compared to when the brake is on, so as to reduce the change in deceleration and ensure operational performance in a way that does not cause disharmony to the operator.

[0055] Figure 4 This is a flowchart illustrating an example of the control process during deceleration.

[0056] In step S1, it is determined whether to engage the lock-up clutch 3a and perform regenerative power generation using the alternator 11. Regenerative power generation by the alternator 11 is performed, for example, when conditions for regenerative power generation are met, such as the accelerator pedal being unpressed or the vehicle battery's state of charge (SOC) being greater than a predetermined battery threshold. If regenerative power generation is performed in step S1, the process proceeds to step S2. If regenerative power generation is not performed in step S1, the process ends.

[0057] In step S2, a first speed threshold V1 and a second speed threshold V2 corresponding to the deceleration are calculated. The first speed threshold V1 and the second speed threshold V2 are calculated, for example, by pre-storing a correspondence map between deceleration and speed thresholds in the control unit 21.

[0058] In step S3, it is determined whether the vehicle speed is less than or equal to the second speed threshold V2. If the vehicle speed is less than or equal to the second speed threshold V2 in step S3, proceed to step S4. If the vehicle speed is not less than or equal to the second speed threshold V2 in step S3, proceed to step S5.

[0059] In step S4, the regenerative power generation of the alternator 11 is terminated.

[0060] In step S5, it is determined whether locking is in progress, i.e., whether the lock-up clutch 3a is engaged. If the lock-up clutch 3a is disengaged in step S5, the process proceeds to step S4. If the lock-up clutch 3a is engaged in step S5, the process proceeds to step S6.

[0061] In step S6, it is determined whether to cut off fuel to the internal combustion engine 1. If fuel cut-off is not performed in step S6, proceed to step S4. If fuel cut-off is performed in step S6, proceed to step S2.

[0062] The specific embodiments of the present invention have been described above, but the present invention is not limited to the above embodiments, and various modifications can be made without departing from its spirit. For example, regarding the regenerative power generation of the alternator, if the vehicle speed reaches a second vehicle speed set according to the vehicle's deceleration, the process does not end, and it is acceptable to end the process by disengaging the lock-up clutch.

[0063] The above embodiments relate to vehicle control methods and vehicle control devices.

Claims

1. A method for controlling a vehicle, the vehicle comprising an internal combustion engine, an automatic transmission, a lock-up clutch directly connecting the internal combustion engine and the automatic transmission, and an alternator, as an auxiliary device of the internal combustion engine, always directly connected to the internal combustion engine and capable of being driven by the internal combustion engine, wherein, The above control methods are implemented as follows: When decelerating, it operates in the first operating mode, in which the lock-up clutch is engaged and the internal combustion engine is directly connected to the automatic transmission, and regenerative power generation is performed using the alternator. In the first operating mode described above, if the vehicle speed reaches a first vehicle speed set according to the vehicle's deceleration, the lock-up clutch is disengaged; and In the operation of the first operating mode, if the vehicle speed reaches a second vehicle speed that is higher than the first vehicle speed, the regenerative power generation using the alternator will end, so that the end of the regenerative power generation using the alternator is earlier than the disengagement of the lock-up clutch.

2. The vehicle control method according to claim 1, wherein, The speed of the second vehicle mentioned above is set based on the vehicle's deceleration.

3. The vehicle control method according to claim 1, wherein, This causes the aforementioned lock-up clutch to disengage earlier than the end of the regenerative power generation of the aforementioned alternator.

4. The vehicle control method according to claim 2 or 3, wherein, The greater the deceleration of the vehicle, the greater the increase in the speed of the first vehicle or the second vehicle mentioned above.

5. The vehicle control method according to claim 2 or 3, wherein, The internal combustion engine drives the air conditioner compressor. The higher the refrigerant pressure in the air conditioner, the higher the speed of the first vehicle or the second vehicle mentioned above.

6. The vehicle control method according to any one of claims 1 to 3, wherein, The speed of the first vehicle or the speed of the second vehicle is changed when the brake is engaged or disengaged.

7. A vehicle control device, wherein, The vehicle's control device has: internal combustion engine; Automatic transmission; A lock-up clutch that directly connects the aforementioned internal combustion engine to the aforementioned automatic transmission; An alternator, which serves as an auxiliary device to the aforementioned internal combustion engine and is always directly connected to and can be driven by the internal combustion engine; and The control unit performs the following actions: When decelerating, it operates in a first operating mode, wherein the lock-up clutch is engaged, and regenerative power generation is performed using the alternator while the internal combustion engine and the automatic transmission are directly connected. In the first operating mode, if the vehicle speed reaches a first vehicle speed set according to the vehicle's deceleration during deceleration, the control unit disengages the lock-up clutch. In the first operating mode, if the vehicle speed reaches a second vehicle speed higher than the first vehicle speed during deceleration, the control unit terminates the regenerative power generation using the alternator, such that the termination of the regenerative power generation by the alternator occurs earlier than the disengagement of the lock-up clutch.

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