Vehicle control device

Abstract

The objective of this invention is to simultaneously suppress wheel vibration and improve the lag in driving force during ABS activation. The vehicle control device includes: a vehicle drive source; a transmission that transmits driving force from the vehicle drive source to the wheels; a clutch located between the vehicle drive source and the transmission; and an anti-lock braking system (ABS) capable of braking the wheels. When the ABS is activated and the acceleration request is below a first threshold, clutch slip control is initiated; when the ABS is not activated and the acceleration request is above a second threshold, clutch slip control is terminated.

Description

Technical Field

[0001] The present invention relates to a vehicle control device that controls the operation of a clutch in a vehicle, the vehicle having a transmission that transmits driving force from a vehicle drive source to the wheels, a clutch between the vehicle drive source and the transmission, and an anti-lock braking system (hereinafter referred to as ABS) capable of braking the wheels individually. Background Technology

[0002] ABS is used in various vehicles. When a wheel's rotation is lower than the value estimated based on the driving speed during braking, ABS determines that the wheel is locked and the vehicle is coasting. It then reduces the hydraulic pressure on the wheel brakes. If the wheel starts to rotate again, the hydraulic pressure is applied again to activate the brakes. By automatically repeating the above actions, it prevents wheel lock-up and aims to maximize braking force.

[0003] In this context, vehicles equipped with drive motors that have significant inertia, such as electric vehicles or hybrid vehicles, sometimes experience wheel vibrations when the ABS is activated, triggered by the braking force control. To suppress these wheel vibrations, a clutch slip control technology that disengages or slips the clutch has been proposed (see Patent Document 1).

[0004] Patent Document 1: Japanese Patent Application Publication No. 2022-106556 Summary of the Invention

[0005] Here, if the clutch disengages or slips, the clutch plates move, and therefore re-engagement of the clutch requires a certain amount of time. This results in a delay in the acceleration response to throttle input before re-engagement, which the driver may sometimes perceive as sluggishness. Furthermore, if the clutch slips, the driving force transmitted to the transmission differs from when it is engaged. Therefore, in this case, a sluggish response to throttle input may also be felt.

[0006] The present invention relates to a vehicle control device comprising: a vehicle drive source; a transmission that transmits driving force from the vehicle drive source to the wheels; a clutch located between the vehicle drive source and the transmission; and an anti-lock braking system capable of braking the wheels. When the anti-lock braking system is activated, if the acceleration request is below a first threshold, slip control of the clutch is initiated; when the anti-lock braking system is not activated and the acceleration request is greater than a second threshold, slip control of the clutch is terminated.

[0007] Furthermore, the acceleration request amount can be the amount of operation of the accelerator pedal.

[0008] Invention Effects

[0009] It can both suppress wheel vibration when ABS is activated and improve the sluggishness of driving force. Attached Figure Description

[0010] Figure 1 This is a diagram showing the main structural components of vehicle 100.

[0011] Figure 2 This is a flowchart showing the start and end actions of the slip control in Implementation Method 1.

[0012] Figure 3 This is a flowchart showing the start and end actions of the slip control in Implementation Method 2.

[0013] Figure 4 This is a flowchart showing the start and end actions of the slip control in Implementation Method 3.

[0014] Figure 5 This is a flowchart showing the start and end actions of the slip control in Implementation Method 4.

[0015] Figure 6 This is a flowchart illustrating the start and end actions of the slip control in Implementation 5.

[0016] Figure 7 This is a flowchart showing the start and end actions of the slip control in Implementation 6. Detailed Implementation

[0017] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Furthermore, the following embodiments do not limit the present invention, and structures selectively combined from multiple examples are also included in the present invention.

[0018] "Overall structure"

[0019] Figure 1 This diagram shows the main structural components of vehicle 100. Vehicle drive source 10 is a device that generates driving force for the movement of vehicle 100. In the case of an electric vehicle, it is a drive motor; in the case of a hybrid vehicle, it includes both a motor generator and an engine.

[0020] A clutch 12 is connected to the output shaft of the vehicle drive source 10. The clutch 12 can completely cut off the transmission of the input drive force, and can also slip in a way that transmits a certain amount of drive force.

[0021] The output shaft of clutch 12 is connected to transmission 14. Transmission 14 can, for example, switch the transmission gear ratio and change the speed of the output side relative to the input side. Alternatively, the transmission can be a continuously variable transmission (CVT) or may not include a torque converter.

[0022] Wheels 16 are connected to the transmission 14. The wheels 16 rotate by the driving force output from the transmission 14, thereby driving the vehicle 100. The wheels 16 have four wheels: right front wheel FR, left front wheel FL, right rear wheel RR, and left rear wheel RL. In this example, it is a two-wheel drive system, which can transmit the driving force from the transmission 14 to the left and right wheels 16.

[0023] Each wheel 16 is equipped with a brake 18, which brakes each wheel 16 individually. In addition, each wheel 16 is equipped with a wheel speed sensor 20, which can detect the rotational speed (wheel speed) of each wheel 16 individually.

[0024] In addition, the vehicle drive source 10, clutch 12, and transmission 14 are referred to as powertrain 22, and the output torque of transmission 14 is referred to as powertrain drive torque.

[0025] The control unit 30 controls the vehicle's movement. The control unit 30 receives various signals containing vehicle status parameters and performs various controls based on these input signals. In this example, the outputs of the accelerator pedal operation sensor, throttle opening sensor, powertrain drive torque sensor, brake pedal operation sensor, and wheel speed sensor 20 are input to the control unit 30. Furthermore, the throttle opening sensor detects the output from the engine when it is powered, and the powertrain drive torque is obtained by detecting the output torque of the transmission 14.

[0026] The control unit 30 controls the output of the vehicle drive source 10, the engagement / disengagement of the clutch 12, and the gear ratio of the transmission based on input signals. Furthermore, a brake actuator 32 is connected to the control unit 30. The brake actuator 32 individually drives the four brakes 18. The control unit 30 also includes an ABS control unit 34. The ABS control unit 34 actively controls the operation of the brake actuator 32 according to the vehicle's condition. That is, when it is determined that the wheels 16 are locked and slipping, the braking force of the brakes 18 is temporarily reduced, and braking is resumed when the wheels 16 begin to rotate again. For example, the necessity is determined based on the detection values ​​of the wheel speed sensors 20 installed on each wheel 16 and the operating amount of each brake 18 based on the brake actuator 32, and the braking of each wheel 16 is controlled individually.

[0027] Furthermore, the control unit 30 includes a powertrain control unit 36, which controls the disengagement of the clutch 12 and the gear ratio of the transmission 14 according to the vehicle status. The ABS control unit 34 and the powertrain control unit 36 ​​are part of the functions of the control unit 30, but they can also be configured as separate, independent computers.

[0028] In addition, ABS includes ABS control unit 34, brake actuator 32, and brake 18. However, brake actuator 32 and brake 18 are originally components of the vehicle, so ABS control unit 34 can also correspond to ABS.

[0029] In such vehicles, vibrations sometimes occur due to the braking force control when the ABS is engaged. In the control unit 30, upon detecting this vibration, slip control is executed to disengage or slip the clutch 12, thereby suppressing the vibration. By executing slip control, the power transmission between the vehicle drive source 10 and the transmission 14 is limited, thus mitigating vibrations based on the mismatch in torque transmission between the vehicle drive source 10 and the wheels 16.

[0030] “Implementation Method 1”

[0031] Figure 2 This is a flowchart showing the start and end actions of the slip control in Implementation Method 1.

[0032] First, when the control unit 30 (ABS control unit 34) detects slippage caused by the locking of the wheel 16 during braking, it starts to perform ABS control (=activate ABS) as described above, and if the specified conditions are met, it ends ABS control (=activate ABS).

[0033] That is, the control unit 30 determines whether to perform ABS control, and controls the powertrain 22 and brake actuator 32 based on the result of the determination. This control is repeated at certain intervals during vehicle operation.

[0034] Then, in parallel with this ABS control, a system based on... Figure 2 The start / end processing of the slip control of clutch 12.

[0035] First, determine whether either of the left or right drive wheels is under ABS control and whether the accelerator pedal operation amount is below threshold A (S11).

[0036] Typically, ABS control is initiated when the brake pedal is depressed, at which point the accelerator pedal is usually not depressed. Therefore, it is assumed that the S11 judgment will be "yes" more often when ABS control is initiated.

[0037] If the determination in S11 is "yes", the slip control of clutch 12 is activated (slip control) (S12). This slip control also includes the case where clutch 12 is completely disengaged. Furthermore, if no vibration occurs, clutch 12 remains engaged, and normally clutch 12 is not disengaged. That is, activating slip control means that the determination to perform slip control is valid.

[0038] This prevents vibrations caused by implementing ABS control.

[0039] Then, if the driver presses the accelerator pedal and the amount of operation is greater than the threshold A, then the determination in S11 is negative.

[0040] If the decision in S11 is "No", then it is determined whether either of the following conditions is met: the left and right drive wheels are not under ABS control or the throttle operation amount is greater than the threshold A' (S13). If either condition is met, the slip control of the clutch 12 is terminated (S14). In addition, the throttle operation amount is one of the acceleration request amounts.

[0041] In other words, if ABS control is not in effect, acceleration corresponding to the amount of accelerator pedal input is preferred. If the amount of accelerator pedal input (pressing) is relatively large, it is assumed that the driver desires acceleration, and acceleration is preferred in this case as well. Therefore, slip control is terminated, and acceleration control corresponding to the amount of accelerator pedal input is implemented.

[0042] If the result of S13 is "No", it is considered that the slip control of clutch 12 can continue and the process ends directly. In addition, if the S13 judgment is made without ABS control or clutch 12 slip control, it simply means that the slip control is not performed in S14, which is not a problem.

[0043] Thus, according to Figure 2 The clutch slip control process only initiates when either the left or right drive wheel is under ABS control and the accelerator pedal operation amount is below a threshold A. Then, when executing clutch 12 slip control, the slip control ends when the ABS control of the drive wheel ends or the accelerator pedal operation amount exceeds a certain threshold A'. Therefore, slip control does not initiate when the driver depresses the accelerator pedal beyond a certain amount. Furthermore, slip control ends when ABS control is not in effect and the driver depresses the accelerator pedal beyond a certain amount. A is the threshold value for the accelerator pedal operation amount when clutch slip control is initiated, and A' is the threshold value when it ends. A and A' can be the same value or different values. For example, an arbitrary offset can be set to avoid jitter in the ON / OFF decision of the control.

[0044] This control allows the slip control of clutch 12 to be terminated when the driver wants to accelerate, thereby reducing the lag in vehicle acceleration.

[0045] “Implementation Method 2”

[0046] Figure 3 This is a flowchart showing the start and end actions of the slip control in Implementation Method 2.

[0047] Determine whether either of the left or right drive wheels is under ABS control, whether the accelerator pedal operation amount is below threshold A, and whether the rate of change of the accelerator pedal operation amount is below threshold B (S21).

[0048] If the determination in S21 is "yes", the slip control of clutch 12 is activated (S22).

[0049] If the determination in S21 is "No", determine whether any of the following conditions are met: the left and right drive wheels are not under ABS control, the throttle operation amount is greater than threshold A', or the throttle pedal operation amount change rate is greater than threshold B' (S23). If any of the conditions are met, end the slip control of clutch 12 (S24).

[0050] Thus, in Figure 3 In the example, the rate of change of accelerator pedal operation is added to the judgment criteria of S21 and S23. When the rate of change of accelerator pedal operation is lower than the threshold B, the clutch slip control is also initiated. When executing the slip control of clutch 12, the slip control of clutch 12 is terminated when the accelerator pedal operation exceeds the threshold B'. In addition, A and A', B and B' can be the same value, or they can be set differently.

[0051] Therefore, even with small accelerator pedal inputs, slip control will not initiate as long as the rate of change in input is large, and slip control will terminate even with small accelerator pedal inputs as long as the rate of change in input is large. This results in vehicle behavior that better matches the driver's feel.

[0052] “Implementation Method 3”

[0053] Figure 4 This is a flowchart showing the start and end actions of the slip control in Implementation Method 3.

[0054] Determine whether either the left or right drive wheel is under ABS control, and that the rate of change of the accelerator pedal operation amount + K × accelerator pedal operation amount is less than or equal to the threshold C (S31). That is, replace... Figure 2 In the example where the throttle input is ≤ A, a judgment criterion is set where the throttle pedal input + K × throttle pedal input change rate is ≤ threshold C. Here, K is a defined constant, and the weights of the throttle pedal input and the throttle pedal input change according to the magnitude of K.

[0055] If the determination in S31 is "yes", the slip control of clutch 12 is activated (S32).

[0056] If the determination in S31 is "No", it is determined that the left and right drive wheels are not under ABS control, or the accelerator pedal operation amount + K' × accelerator pedal operation amount change rate is less than or equal to the threshold C' (S33). If either condition is met, the slip control of clutch 12 is terminated (S24).

[0057] Thus, in Figure 3 In the example, the judgment criteria for S21 and S23 use "accelerator pedal operation amount + K × accelerator pedal operation amount change rate ≤ threshold C" and "operation amount + K × accelerator pedal operation amount change rate ≤ threshold C'". This establishes a correlation between the two judgment criteria for judgment, rather than judging them separately. In addition, K and K', C and C' can be the same value, or they can be set to have differences.

[0058] “Implementation Method 4”

[0059] Figure 5 This is a flowchart showing the start and end actions of the slip control in Implementation Method 4.

[0060] Determine whether either the left or right drive wheel is under ABS control and whether the throttle opening is ≤ threshold D (S41). That is, replace Figure 2 In Implementation Method 1, the throttle operation amount is ≤A, and a judgment criterion is set for the throttle opening degree being ≤Threshold D. When using an internal combustion engine as the vehicle drive source 10, the throttle opening degree can be used instead of the throttle pedal operation amount. Figure 3 , Figure 4 In implementation methods 2 and 3, the throttle opening can also be used instead of the throttle operation amount.

[0061] If the determination in S41 is "yes", the slip control of clutch 12 is activated (S42).

[0062] If the determination in S41 is "No", it is determined that the left and right drive wheels are not under ABS control or the throttle opening is less than or equal to the threshold D' (S43). If either condition is met, the slip control of the clutch 12 is terminated (S44).

[0063] Thus, in Figure 5 In the example, the judgment criteria for S21 and S23 use whether the throttle opening is below a specified value. When the vehicle drive source 10 is an internal combustion engine, it is possible to perform more appropriate control than the throttle opening. In addition, D and D' can be the same value or they can be set differently.

[0064] “Implementation Method 5”

[0065] Figure 6 This is a flowchart illustrating the start and end of the sliding control actions in Implementation 5.

[0066] Determine whether either the left or right drive wheel is under ABS control and whether the powertrain drive torque is ≤ threshold E (S51). That is, instead of Figure 2 In the example, the throttle input is ≤A, and a judgment criterion is set for the powertrain drive torque being ≤ threshold E. The powertrain drive torque is a torque close to the actual torque transmitted to the wheels, thus enabling appropriate control.

[0067] If the determination in S51 is "yes", the slip control of clutch 12 is activated (S52).

[0068] If the determination in S51 is "No", it is determined that the left and right drive wheels are not under ABS control or the powertrain drive torque is less than or equal to the threshold E' (S53). If either condition is met, the slip control of clutch 12 is terminated (S54).

[0069] Thus, in Figure 6 In the example, the judgment criteria for S21 and S23 use whether the powertrain drive torque is below a specified value. Furthermore, E and E' can be the same value or different. And, in Figure 3 , Figure 4 In implementation methods 2 and 3, the powertrain drive torque can also be used instead of the throttle input.

[0070] “Implementation Method 6”

[0071] Figure 7 This is a flowchart showing the start and end actions of the slip control in Implementation 6.

[0072] In this example, the four-wheel drive vehicle in Implementation 4 is taken as the object. Therefore, instead of the judgment of "whether either of the left or right drive wheels is under ABS control" in S51, the judgment of "whether at least one of the wheels is under ABS control" is adopted, and instead of "neither of the left or right drive wheels is under ABS control" in S53, the judgment of "neither of the wheels is under ABS control" is adopted.

[0073] Furthermore, the same method can be applied in embodiments 1-3 and 5. Figure 7 The judgment.

[0074] In the above embodiments, the throttle operation amount, the rate of change of throttle pedal operation amount, the throttle opening, the powertrain drive torque and the acceleration request amount correspond, the thresholds A, B, C, D, and E correspond to the first threshold, and the thresholds A', B', C', D', and E' correspond to the second threshold.

[0075] Symbol Explanation

[0076] 10-Vehicle drive source, 12-Clutch, 14-Transmission, 16-Wheel, 18-Brake, 20-Wheel speed sensor, 21-Clutch, 22-Powertrain, 30-Control unit, 32-Brake actuator, 34-ABS control unit, 36-Powertrain control unit, 100-Vehicle.

Claims

1. A vehicle control device, characterized in that, It includes: a vehicle drive source; a transmission that transmits driving force from the vehicle drive source to the wheels; a clutch located between the vehicle drive source and the transmission; and an anti-lock braking system capable of braking the wheels. When the anti-lock braking system is activated, if the acceleration request is below a first threshold, the clutch slip control is engaged. If the anti-lock braking system is not in operation and the acceleration request is greater than the second threshold, the clutch slip control is terminated.

2. The vehicle control device according to claim 1, characterized in that, The acceleration request quantity is the amount of operation of the accelerator pedal.

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