Vehicle control system and control method

Abstract

By increasing the target acceleration, acceleration responsiveness is improved, while the increased target acceleration is then brought back to the original target acceleration to avoid causing any discomfort to the driver. [Solution] The vehicle control system 10 includes a drive source 1, an accelerator opening sensor 5 for detecting the accelerator opening, and a control device 3 for controlling the drive source 1 based on the accelerator opening. The control device determines a first target acceleration corresponding to the accelerator opening, and also determines a second target acceleration greater than the first target acceleration. The control device controls the torque of the drive source based on the first or second target acceleration. During the control of the torque of the drive source based on the second target acceleration, when the rate of change of the accelerator opening decreases from an increasing state to a state of decreasing by a predetermined value or more, the control device adjusts the second target acceleration based on the first target acceleration and the rate of change of the accelerator opening to gradually converge to the first target acceleration, and controls the torque of the drive source based on the second target acceleration.

Description

Technical Field

[0001] The present invention relates to a vehicle control system and a control method that set a target acceleration and control the torque of a drive source based on the target acceleration.

Background Art

[0002] Conventionally, there has been known a technique of setting a target acceleration based on a driver's accelerator operation or the like and controlling the torque of a drive source such as an engine or a motor so that the target acceleration is achieved. For example, there is known a technique of improving acceleration responsiveness by performing correction to increase a target acceleration corresponding to an accelerator opening when the vehicle is accelerating (Patent Document 1). In particular, Patent Document 1 describes that when the operation speed of an accelerator pedal is a predetermined value or more, a target acceleration is increased by applying a predetermined gain.

[0003] In addition, a technique related to the present invention is described in, for example, Patent Document 2. In Patent Document 2, two target accelerations (a future target acceleration and an immediate target acceleration) are obtained based on an accelerator opening and a change rate of a target acceleration, respectively, and in a case where one of the target accelerations (the smaller one) is adopted, it is described that the target acceleration is smoothly changed to the other target acceleration (the larger one). Thereby, the vehicle is accelerated while suppressing a sense of discomfort given to a passenger.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

[0006] The present invention was made to solve the problems of the prior art described above, and aims to provide a vehicle control system and control method that improves acceleration responsiveness by increasing the target acceleration, and that can converge the increased target acceleration back to the original target acceleration without causing discomfort to the driver. [Means for solving the problem]

[0007] To achieve the above objective, the present invention provides a vehicle control system comprising: a drive source that generates driving force for the vehicle; an accelerator opening sensor that detects the accelerator opening, which is the opening degree of the accelerator pedal of the vehicle; and a control device configured to control the drive source based on the accelerator opening detected by the accelerator opening sensor. The control device is configured to determine at least a first target acceleration to be set according to the accelerator opening, and at least a second target acceleration set to be greater than the first target acceleration, to control the torque of the drive source based on the first target acceleration or the second target acceleration, and, while controlling the torque of the drive source based on the second target acceleration, when the rate of change of the accelerator opening decreases from a state in which it was increasing to a state in which it was decreasing by a predetermined value or more, to adjust the second target acceleration based on the first target acceleration and the rate of change of the accelerator opening so as to gradually converge to the first target acceleration, and to control the torque of the drive source based on the second target acceleration.

[0008] With the present invention configured in this way, acceleration responsiveness can be improved by performing acceleration control based on a second target acceleration that is greater than the first target acceleration. At the same time, when the rate of change of the accelerator opening decreases significantly during this acceleration control, the second target acceleration can be gradually converged to the first target acceleration. This prevents the driver from experiencing acceleration exceeding their expectations by continuing to use the second target acceleration, which would otherwise make subsequent driving operations difficult. In particular, the present invention takes into account the first target acceleration corresponding to the accelerator opening and the rate of change of the accelerator opening when converging the second target acceleration to the first target acceleration, thus preventing the driver from feeling any discomfort during this convergence. Therefore, the present invention makes it possible to improve the overall driving feel during acceleration.

[0009] In the present invention, preferably, the control device is configured to determine a convergence speed for converging the second target acceleration to the first target acceleration based on the rate of change of the first target acceleration and the accelerator opening, and to adjust the second target acceleration based on the said convergence speed. By adjusting the second target acceleration based on this convergence rate, it is possible to effectively prevent discomfort for the driver during the convergence of the second target acceleration.

[0010] In the present invention, preferably, the control device is configured to increase the convergence speed when the rate of change of the accelerator opening is negative compared to when the rate of change of the accelerator opening is 0 or greater. According to the present invention configured in this way, the second target acceleration can be quickly returned to the first target acceleration in accordance with the situation where the rate of change of the accelerator opening is negative, that is, the situation where the accelerator pedal is being released.

[0011] In the present invention, preferably, the control device is configured to increase the convergence speed when the first target acceleration is decreasing compared to when the first target acceleration is increasing. With the present invention configured in this way, the second target acceleration can be quickly returned to the first target acceleration in accordance with the situation where the first target acceleration is decreasing.

[0012] In the present invention, preferably, the control device is configured to increase the convergence speed when the rate of change of the accelerator opening is positive and the first target acceleration is decreasing, compared to when the rate of change of the accelerator opening is approximately 0. According to the present invention configured in this way, when the first target acceleration is decreasing, the first target acceleration is given priority over the rate of change in the accelerator opening, and the second target acceleration can be returned to the first target acceleration more quickly.

[0013] In the present invention, preferably, the control device is configured to reduce the convergence speed when the rate of change of the accelerator opening is positive and the first target acceleration is increasing, compared to when the rate of change of the accelerator opening is approximately 0. According to the present invention configured in this way, when the rate of change of the accelerator opening is positive and the first target acceleration is increasing, that is, when the vehicle has a strong tendency to accelerate, the second target acceleration can be slowly returned to the first target acceleration.

[0014] In a preferred example of the present invention, the control device includes a control map in which convergence speeds are defined in correspondence with the rate of change of a first target acceleration and the accelerator opening, and is configured to determine the convergence speed corresponding to the current rate of change of the first target acceleration and the current accelerator opening from the control map, and to adjust the second target acceleration based on said convergence speed.

[0015] In the present invention, preferably, the control device is configured to terminate the control of the torque of the drive source based on the second target acceleration and to start the control of the torque of the drive source based on the first target acceleration when the adjusted second target acceleration reaches the first target acceleration. According to the present invention configured in this way, after convergence to the second target acceleration, normal acceleration control based on the first target acceleration can be started promptly.

[0016] From another perspective, the present invention is a vehicle control method executed by a control device in a vehicle having a drive source that generates a driving force of the vehicle, an accelerator opening sensor that detects an accelerator opening which is the opening degree of an accelerator pedal of the vehicle, and a control device configured to control the drive source based on the accelerator opening detected by the accelerator opening sensor. The method includes: obtaining a first target acceleration to be set at least according to the accelerator opening, obtaining a second target acceleration set to be at least greater than the first target acceleration, and controlling the torque of the drive source based on the first target acceleration or the second target acceleration; and during the control of the torque of the drive source based on the second target acceleration, when the change rate of the accelerator opening decreases from a state where it was increasing to a state where it is less than or equal to a predetermined value, adjusting the second target acceleration to gradually converge to the first target acceleration based on the first target acceleration and the change rate of the accelerator opening, and controlling the torque of the drive source based on the adjusted second target acceleration.

Advantages of the Invention

[0017] According to the vehicle control system and control method of the present invention, by increasing the target acceleration, the acceleration responsiveness can be improved, and the increased target acceleration can be made to converge to the original target acceleration so as not to give the driver a sense of discomfort.

Brief Description of the Drawings

[0018] [Figure 1] It is a schematic configuration diagram of a vehicle to which a vehicle control system according to an embodiment of the present invention is applied. [Figure 2] It is an explanatory diagram of basic acceleration control using a first target acceleration according to an embodiment of the present invention. [Figure 3] It is an explanatory diagram of acceleration control using a second target acceleration according to an embodiment of the present invention. [Figure 4] It is a flowchart showing acceleration control according to an embodiment of the present invention. [Figure 5] It shows a control map of the convergence speed according to an embodiment of the present invention.

Best Mode for Carrying Out the Invention

[0019] Hereinafter, a vehicle control system and a control method according to an embodiment of the present invention will be described with reference to the accompanying drawings.

[0020] [Overall Configuration] First, referring to FIG. 1, the overall configuration of the vehicle control system according to the present embodiment will be described. FIG. 1 is a schematic configuration diagram of a vehicle to which the vehicle control system according to the present embodiment is applied.

[0021] As shown in FIG. 1, the vehicle 20 includes a drive source 1 that generates a driving force of the vehicle 20 such as an engine (internal combustion engine) or an electric motor, a control device 3 configured to control the drive source 1, an accelerator opening sensor 5 that detects an accelerator opening which is the opening of an accelerator pedal (not shown) of the vehicle 20, a vehicle speed sensor 7 that detects the speed (vehicle speed) of the vehicle 20, and an acceleration sensor 9 that detects the acceleration of the vehicle 20. A vehicle control system 10 having these is mounted on the vehicle 20. In addition to these sensors 5, 7, and 9, the vehicle 20 is provided with various sensors (for example, when the vehicle 20 has a transmission, a gear position sensor that detects the gear position set in this transmission, etc.).

[0022] The control device 3 is composed of a computer including one or more processors 3a (typically a CPU), and a memory 3b such as a ROM and a RAM that stores various programs (including basic control programs such as an OS and application programs that are started on the OS and realize specific functions) and various data interpreted and executed on the processor 3a.

[0023] In the present embodiment, the control device 3 sets a target acceleration that the vehicle should generate based on the accelerator opening detected by the accelerator opening sensor 5, the vehicle speed detected by the vehicle speed sensor 7, etc., and controls the torque of the drive source 1 so that the target acceleration is realized. Details of the control performed by this control device 3 will be described later.

[0024] [Control Method] Next, with reference to Figures 2 and 3, the control method performed by the control device 3 in this embodiment will be described.

[0025] First, the basic acceleration control in this embodiment will be explained with reference to Figure 2. In Figure 2, graph G11 shows the change in accelerator opening over time, and graph G12 shows the change in the basic (base) first target acceleration set according to this accelerator opening over time.

[0026] As shown in Figure 2, at time t11, while the vehicle 20 is in steady-state driving, the driver begins to press the accelerator pedal, increasing the accelerator opening (wherein "steady-state driving" means when the vehicle speed is greater than 0 and there is no acceleration (the same applies hereinafter), and basically the first target acceleration is set to 0). In particular, at time t11, the rate of change in the accelerator opening increases by 1% or more. From this time t11, the control device 3 sets a first target acceleration that increases in accordance with the increase in the accelerator opening, and controls the torque of the drive source 1 so that this first target acceleration is achieved. In this case, the control device 3 sets the first target acceleration according to the vehicle speed and the gear stage of the transmission of the vehicle 20, in addition to the accelerator opening. For example, the first target acceleration may be set by the method described in Patent Document 1 above.

[0027] Incidentally, as mentioned above, when the acceleration of the vehicle 20 begins (when the driver starts pressing the accelerator pedal), if the acceleration of the vehicle 20 is small, the driver cannot perceive the acceleration. More specifically, when the target acceleration is less than a predetermined acceleration Ac1, the driver cannot perceive the acceleration. This predetermined acceleration Ac1 corresponds to the minimum acceleration at which a human can perceive the start of acceleration (minimum perceptible acceleration), for example, 0.27 to 0.3 m / s². 2 This is acceleration within the specified range.

[0028] In this case, if the vehicle 20 is accelerated based on the first target acceleration as shown in graph G12 of Figure 2, the first target acceleration will be less than the predetermined acceleration Ac1 during the period T11 from time t11 to time t12 at the start of acceleration, so the driver will not perceive the acceleration. If this period T11 is long, the driver tends to feel that the acceleration response is poor.

[0029] Therefore, in this embodiment, in order to improve acceleration responsiveness at the start of acceleration, the acceleration of the vehicle 20 is increased rapidly in order to shorten the time during which the acceleration of the vehicle 20 is less than a predetermined acceleration Ac1. For this purpose, in this embodiment, the control device 3 sets a second target acceleration that increases at a larger rate of change (slope) than the first target acceleration at the start of acceleration. In this case, the control device 3 sets the second target acceleration so as to increase the jerk (acceleration rate) of the vehicle 20 within a range that does not cause discomfort to the driver, specifically so as to increase the jerk of the vehicle 20 within a range less than a predetermined jerk.

[0030] Next, with reference to Figure 3, acceleration control using the second target acceleration according to this embodiment will be described. In Figure 3, graph G21 shows the change in accelerator opening over time, graph G22 shows the change in the rate of change of accelerator opening over time, graph G23 shows the change in the first target acceleration over time, graph G24 shows the change in the second target acceleration over time, and graph G25 shows the change in the jerk of the vehicle 20 (corresponding to the target jerk over time).

[0031] As shown in Figure 3, at time t21, during steady-state driving of the vehicle 20 (period T21), the driver begins to press the accelerator pedal, causing the rate of change in accelerator opening to increase by 1% or more (graph G21). From this time t21, the control device 3 sets a second target acceleration that increases at a larger rate of change (slope) than the first target acceleration (graph G24, arrow Ar1) in order to increase the jerk of the vehicle 20 within a range below a predetermined jerk (graph G25), and controls the torque of the drive source 1 based on this second target acceleration. When setting the second target acceleration in this way, the control device 3 also determines the first target acceleration in parallel (graph G23). However, at this point, the control device 3 performs acceleration control based on the second target acceleration (period T22), and does not use the first target acceleration when performing acceleration control.

[0032] More specifically, the control device 3 sets the predetermined jerk based on at least one of the following: the rate of increase in accelerator opening, vehicle speed, gear position of the transmission in the vehicle 20, the rate of change (slope) of the first target acceleration, and the gradient of the road the vehicle 20 travels on. The control device 3 then sets the second target acceleration so as to increase the jerk of the vehicle 20 within a range less than the predetermined jerk. For example, the control device 3 sets the second target acceleration so as to quickly increase the jerk of the vehicle 20 to the predetermined jerk and maintain this predetermined jerk.

[0033] Subsequently, at time t22, the second target acceleration reaches a predetermined acceleration Ac1. The predetermined acceleration Ac1 is set in advance based on the minimum perceived acceleration described above, for example, 0.27 to 0.3 m / s². 2 The acceleration is within this range. From time t22, the control device 3 stops increasing the second target acceleration at a larger rate of change than the first target acceleration, and sets the second target acceleration to change at the same rate of change (slope) as the first target acceleration while maintaining the difference between them, and controls the torque of the drive source 1 based on the second target acceleration.

[0034] Subsequently, at time t23, the rate of change in accelerator opening changes from an increasing state to a state where it decreases by more than a predetermined value; in other words, the rate of change in accelerator opening shifts from increasing to decreasing by more than a predetermined value (Graph G22). From time t23, the control device 3 adjusts the second target acceleration to gradually converge to the first target acceleration (arrow Ar2), and controls the torque of the drive source 1 based on this second target acceleration. By doing so, by converging the second target acceleration to the first target acceleration, the control device 3 prevents the driver from continuing to use the second target acceleration, which would result in acceleration exceeding the driver's expectations and make subsequent driving operations difficult. Specifically, the control device 3 determines the convergence speed to converge the second target acceleration to the first target acceleration based on the first target acceleration and the rate of change in accelerator opening (accelerator pedal operation speed), and adjusts the second target acceleration based on this convergence speed. More specifically, the control device 3 determines the convergence speed by referring to a control map in which the convergence speed is defined in correspondence with the rate of change in the first target acceleration and accelerator opening. This allows the second target acceleration to converge to the first target acceleration, so as not to cause any discomfort to the driver.

[0035] Then, at time t24, when the adjusted second target acceleration reaches the first target acceleration, that is, when the convergence of the second target acceleration to the first target acceleration is completed, the control device 3 terminates the acceleration control based on the second target acceleration and starts acceleration control based on the first target acceleration.

[0036] Furthermore, the control performed from time t21 to time t22 (period T22) corresponds to the "second control" in this invention, and the control performed from time t22 onward corresponds to the "first control" in this invention. The "first control" is basically acceleration control using the first target acceleration, but also includes acceleration control using the second target acceleration which is changed at the same rate of change (slope) as the first target acceleration, while the "second control" is acceleration control using the second target acceleration which is increased at a larger rate of change than the first target acceleration.

[0037] [Control Flow] Next, with reference to Figure 4, a flowchart illustrating acceleration control according to an embodiment of the present invention will be described. This flowchart is repeatedly executed by the control device 3 at a predetermined cycle. Specifically, the processor 3a within the control device 3 reads a program stored in memory 3b and executes the program, thereby realizing the control related to this flowchart.

[0038] First, in step S10, the control device 3 acquires various information, including detected values ​​from at least the accelerator opening sensor 5, the vehicle speed sensor 7, and the acceleration sensor 9. The control device 3 also calculates the average value of the detected value from the accelerator opening sensor 5 over a 30ms period (corresponding to the accelerator opening, hereinafter referred to as "apsfil"), calculates the slope of this apsfil over a 100ms period (corresponding to the change in accelerator opening, hereinafter referred to as "dapsfil"), and calculates the slope of this dapsfil over a 1s period (hereinafter referred to as "ddapsfil").

[0039] Next, in step S11, the control device 3 determines whether the vehicle 20 is in a steady-state driving state. Specifically, the control device 3 determines that the vehicle 20 is in a steady-state driving state if the vehicle speed detected by the vehicle speed sensor 7 is greater than 0 (meaning the vehicle 20 is not stopped) and the acceleration detected by the acceleration sensor 9 (or target acceleration instead of detected acceleration) is 0 (step S11: Yes). In this case, the control device 3 proceeds to step S12.

[0040] In contrast, if the control device 3 does not determine that the vehicle 20 is in a steady-state driving state (step S11: No), for example, if the vehicle 20 is stopped or is already accelerating, it does not proceed to step S12. In particular, in this embodiment, when the vehicle 20 is accelerating from a stopped state, the control device 3 does not perform acceleration control based on the second target acceleration (in this case, it performs acceleration control based on the first target acceleration). This is because if the acceleration is greatly increased from a stopped state by acceleration control based on the second target acceleration, so-called tip-in shocks caused by the backlash of the transmission may occur.

[0041] Next, in step S12, the control device 3 determines whether the dapsfil is equal to or greater than a predetermined value. Here, the control device 3 uses dapsfil to determine whether the rate of change in the accelerator opening has increased by 1% or more. By making this determination, the control device 3 ensures that acceleration control is performed on the vehicle 20 only after confirming to some extent the driver's intention to operate the accelerator pedal. If, as a result of step S12, the control device 3 determines that dapsfil is equal to or greater than a predetermined value (step S12: Yes), it proceeds to step S13. On the other hand, if the control device 3 does not determine that dapsfil is equal to or greater than a predetermined value (step S12: No), that is, if dapsfil is less than a predetermined value, it returns to step S12 and does not proceed to step S13.

[0042] Next, in step S13, the control device 3 determines whether dapsfil has updated its maximum value and whether ddapsfil is below a predetermined value. Here, first, it determines whether the sequentially obtained dapsfil (which fluctuates relatively greatly) has updated its maximum value to confirm the driver's intention to accelerate (acceleration request). Also, by determining whether ddapsfil is below a predetermined value, it confirms whether accelerator operation is being performed due to unintentional foot vibrations caused by impacts such as when the vehicle 20 goes over a bump. In such a situation, a large acceleration should not be generated in the vehicle 20, so acceleration control based on the second target acceleration is not performed (in this case, acceleration control based on the first target acceleration is performed).

[0043] If, as a result of step S13, the control device 3 determines that dapsfil has updated its maximum value and ddapsfil is not below a predetermined value (step S13: No), it proceeds to step S14, sets a first target acceleration, and controls the torque of the drive source 1 so that this first target acceleration is achieved. In this case, the control device 3 sets the first target acceleration according to the accelerator opening, vehicle speed, transmission gear, etc. For example, the control device 3 may set the first target acceleration by the method described in Patent Document 1 above.

[0044] In response to this, if, as a result of step S13, the control device 3 determines that dapsfil has updated its maximum value and ddapsfil is less than a predetermined value (step S13: Yes), it proceeds to step S15, sets a second target acceleration, and controls the torque of the drive source 1 so that this second target acceleration is achieved. Specifically, the control device 3 sets a predetermined jerk based on ddapsfil (corresponding to the rate of increase in accelerator opening), vehicle speed, transmission gear, rate of change (slope) of the first target acceleration, and the gradient of the road the vehicle 20 travels on, and sets a second target acceleration that increases at a larger rate of change than the first target acceleration in order to increase the jerk of the vehicle 20 within a range less than this predetermined jerk (typically, the second target acceleration is set so that the jerk of the vehicle 20 is quickly increased to a predetermined jerk and maintained at this predetermined jerk).

[0045] Here, we will illustrate the specific method for setting the second target acceleration by the control device 3 (in particular, the method for setting the predetermined jerk for setting the second target acceleration). First, when ddapsfil is large, the control device 3 sets a relatively large predetermined jerk in order to significantly increase the second target acceleration. In this case, the control device 3 should use the maximum value of ddapsfil in order to accurately judge the degree of the driver's intention to accelerate. Furthermore, when the vehicle speed is low (around 10-30 km / h) and high (60 km / h or more), the control device 3 sets a relatively small predetermined jerk so as not to widen the difference between the second target acceleration and the first target acceleration. On the other hand, when the vehicle speed is medium (around 30-60 km / h), the control device 3 sets a relatively large predetermined jerk in order to significantly increase the second target acceleration. Also, when the gear is in a low gear (for example, 1st gear), the control device 3 sets a relatively small predetermined jerk in order to suppress shocks. Furthermore, when the rate of change (slope) of the first target acceleration is small, a relatively small predetermined jerk is set. This is because if the rate of change of the second target acceleration is increased when the rate of change of the first target acceleration is small, the rate of change of the second target acceleration will suddenly decrease when the stage of changing the second target acceleration using the rate of change (slope) of the first target acceleration begins (see time t22, period T23 in Figure 3), and the continuity of acceleration will be lost. In addition, when the gradient of the travel path is large, the control device 3 sets a relatively large predetermined jerk in order to increase the second target acceleration.

[0046] As described above, multiple predetermined jerks can be obtained using various parameters. Ultimately, the control device 3 adopts the smallest predetermined jerk among the obtained multiple predetermined jerks and sets the second target acceleration based on this predetermined jerk, for example, setting the second target acceleration that results in the smallest change. This is to suppress discomfort caused to the driver by a large jerk and malfunctions caused by a second target acceleration with a large change or rate of change. Basically, the control device 3 determines the slope of the second target acceleration in particular based on such predetermined jerks.

[0047] Next, after step S15 described above, the control device 3 proceeds to step S16 to determine whether the second target acceleration has reached the predetermined acceleration Ac1. If the control device 3 determines that the second target acceleration has reached the predetermined acceleration Ac1 (step S16: Yes), it proceeds to step S17. If it does not determine that the second target acceleration has reached the predetermined acceleration Ac1 (step S16: No), it returns to step S15. In the latter case, the control device 3 continues acceleration control based on the second target acceleration set in step S15 until the second target acceleration reaches the predetermined acceleration Ac1.

[0048] Next, in step S17, the control device 3 finishes increasing the second target acceleration at a larger rate of change than the first target acceleration, and sets the second target acceleration to change at the same rate of change (slope) as the first target acceleration while maintaining the difference between them, and controls the torque of the drive source 1 based on the second target acceleration. Then, the control device 3 proceeds to step S18.

[0049] Next, in step S18, the control device 3 determines whether the absolute value of the dapsfil decrease rate (%) has become greater than or equal to a predetermined value, that is, whether the rate of change of the accelerator opening has decreased by a predetermined value or more from a state in which it was increasing. As a result, if the control device 3 determines that the absolute value of the dapsfil decrease rate has become greater than or equal to a predetermined value (step S18: Yes), it proceeds to step S19. If it does not determine that the absolute value of the dapsfil decrease rate has become greater than or equal to a predetermined value (step S18: No), it returns to step S17. In the latter case, the control device 3 continues acceleration control based on the second target acceleration set in step S17 until the absolute value of the dapsfil decrease rate becomes greater than or equal to a predetermined value.

[0050] Next, in step S19 and beyond, the control device 3 adjusts the second target acceleration to gradually converge to the first target acceleration, and controls the torque of the drive source 1 based on this second target acceleration. First, in step S19, the control device 3 determines the convergence speed to converge the second target acceleration to the first target acceleration based on the rate of change of the first target acceleration and the accelerator opening (the operating speed of the accelerator pedal). Specifically, the control device 3 refers to a control map in which the convergence speed is defined in correspondence with the rate of change of the first target acceleration and the accelerator opening, and determines the convergence speed corresponding to the current rate of change of the first target acceleration and the current rate of change of the accelerator opening.

[0051] Here, with reference to Figure 5, a control map of the convergence speed according to an embodiment of the present invention will be described. The control map defines the convergence speed in correspondence with the rate of change of accelerator opening (horizontal axis) and the first target acceleration (vertical axis). Specifically, the control map includes four regions R1 to R4 defined by the rate of change of accelerator opening and the first target acceleration, and a convergence speed value (meaning an absolute value) to be applied is set for each of these regions R1 to R4. In this case, one convergence speed value is set for each region R1 to R4. In Figure 5, the rate of change of accelerator opening shown on the horizontal axis is defined to be positive on the right side (indicating that the accelerator pedal is depressed) and negative on the left side (indicating that the accelerator pedal is released), with the center of the horizontal axis (rate of change of 0) as the boundary. The first target acceleration shown on the vertical axis is defined to increase on the upper side and decrease on the lower side, with the center of the vertical axis (where the first target acceleration is constant) as the boundary.

[0052] Region R1 is the region where the rate of change of the accelerator pedal opening is negative (i.e., the region where the accelerator pedal opening is decreasing, or in other words, the region where the accelerator pedal is being released). In this region R1, a relatively large convergence speed is set to quickly return the second target acceleration to the first target acceleration, in accordance with the situation where the accelerator pedal is being released. Region R2 is the region where the rate of change of the accelerator pedal opening is approximately 0 (i.e., the region where the accelerator pedal opening is almost constant, or in other words, the region where the position of the accelerator pedal is almost fixed). In this region R2, a relatively small convergence speed is set to slowly return the second target acceleration to the first target acceleration, in accordance with the situation where the accelerator pedal is hardly being operated. Note that a rate of change of accelerator pedal opening of approximately 0 means that the absolute value of the rate of change is less than a predetermined value close to 0.

[0053] Furthermore, region R3 is a region where the rate of change of the accelerator opening is positive and the first target acceleration is decreasing. In region R3, a relatively large convergence speed is set to quickly return the second target acceleration to the first target acceleration, in accordance with the situation where the first target acceleration is decreasing. In region R4, a relatively small convergence speed is set to slowly return the second target acceleration to the first target acceleration, in accordance with the situation where the first target acceleration is increasing.

[0054] Next, we will explain the relative magnitudes of the convergence speeds set in each region R1 to R4. First, the convergence speed set in region R1 is greater than the convergence speeds set in the other regions R2 to R4. From this, it follows that when the rate of change of the accelerator opening is negative, a larger convergence speed is set than when the rate of change of the accelerator opening is 0 or greater. Also, the convergence speed set in region R3 is greater than the convergence speed set in region R4. Since regions R3 and R4 are divided based on whether the first target acceleration decreases or increases (note that regions R1 and R2 are not defined based on the first target acceleration), from the relationship between regions R3 and R4, it can be said that when the first target acceleration is decreasing, a larger convergence speed is set than when the first target acceleration is increasing.

[0055] Furthermore, the convergence speed set in region R3 is greater than the convergence speed set in region R2. This means that when the rate of change of the accelerator opening is positive and the first target acceleration is decreasing, a greater convergence speed is set than when the rate of change of the accelerator opening is approximately 0. Also, the convergence speed set in region R4 is smaller than the convergence speed set in region R2. This means that when the rate of change of the accelerator opening is positive and the first target acceleration is increasing, a smaller convergence speed is set than when the rate of change of the accelerator opening is approximately 0.

[0056] In the example above, a control map was shown in which one convergence velocity value was set for each region R1 to R4. However, in other examples, multiple convergence velocity values ​​may be set in each region R1 to R4, which change continuously or stepwise depending on the rate of change of the accelerator opening and the magnitude of the first target acceleration. In this case, it is preferable to set a larger convergence velocity as the rate of change of the accelerator opening decreases, and to set a larger convergence velocity as the first target acceleration decreases (in other words, to set a smaller convergence velocity as the first target acceleration increases).

[0057] Returning to Figure 4, after step S19, the control device 3 proceeds to step S20, where it sets a second target acceleration based on the convergence speed determined in step S19, and controls the torque of the drive source 1 based on this second target acceleration. Then, the control device 3 proceeds to step S21, where it determines whether the second target acceleration has reached the first target acceleration, that is, whether the convergence of the second target acceleration to the first target acceleration has been completed. If the control device 3 determines that the second target acceleration has reached the first target acceleration (step S21: Yes), it proceeds to step S22. In this case, the control device 3 terminates the acceleration control based on the second target acceleration and starts acceleration control based on the first target acceleration (step S22). Then, the control device 3 terminates the process shown in the flow chart of Figure 4. On the other hand, if the control device 3 does not determine that the second target acceleration has reached the first target acceleration (step S21: No), it returns to step S19. In this case, the control device 3 determines the convergence speed until the second target acceleration reaches the first target acceleration, and continues acceleration control based on the second target acceleration set from this convergence speed.

[0058] [Mechanism of Action and Effects] Next, the operation and effects of the vehicle control system and control method according to this embodiment will be described.

[0059] In this embodiment, the control device 3 determines a first target acceleration to be set according to the accelerator opening, and a second target acceleration set to be at least greater than the first target acceleration. Based on these first or second target accelerations, the control device 3 controls the torque of the drive source 1. During the control of the torque of the drive source 1 based on the second target acceleration, when the rate of change of the accelerator opening decreases from an increasing state to a state of decreasing by a predetermined value or more, the control device 3 adjusts the second target acceleration to gradually converge to the first target acceleration based on the first target acceleration and the rate of change of the accelerator opening, and controls the torque of the drive source 1 based on the second target acceleration.

[0060] According to this embodiment, acceleration responsiveness can be improved by performing acceleration control based on a second target acceleration that is greater than the first target acceleration. At the same time, when the rate of change of the accelerator opening decreases significantly during this acceleration control, the second target acceleration can be gradually converged to the first target acceleration. This prevents the driver from experiencing acceleration exceeding their expectations by continuing to use the second target acceleration, which would make subsequent driving operations difficult. In particular, in this embodiment, the second target acceleration is converged to the first target acceleration by taking into account the first target acceleration corresponding to the accelerator opening and the rate of change of the accelerator opening, thus preventing any discomfort to the driver during this convergence. As described above, this embodiment makes it possible to improve the overall driving feeling during acceleration.

[0061] Furthermore, in this embodiment, the control device 3 determines a convergence speed to converge the second target acceleration to the first target acceleration based on the rate of change of the first target acceleration and the accelerator opening, and adjusts the second target acceleration based on this convergence speed. By adjusting the second target acceleration based on such a convergence speed, it is possible to effectively prevent the driver from experiencing discomfort during the convergence of the second target acceleration.

[0062] Furthermore, in this embodiment, when the rate of change of the accelerator opening is negative, the control device 3 increases the convergence speed compared to when the rate of change of the accelerator opening is 0 or greater. This allows the second target acceleration to be returned to the first target acceleration more quickly in accordance with the situation where the accelerator pedal is being released.

[0063] Furthermore, in this embodiment, the control device 3 increases the convergence speed when the first target acceleration is decreasing compared to when the first target acceleration is increasing. This allows the second target acceleration to be returned to the first target acceleration more quickly in accordance with the situation where the first target acceleration is decreasing.

[0064] Furthermore, in this embodiment, when the rate of change of the accelerator opening is positive and the first target acceleration is decreasing, the control device 3 increases the convergence speed compared to when the rate of change of the accelerator opening is approximately zero. This allows the control device 3 to prioritize the first target acceleration over the rate of change of the accelerator opening when the first target acceleration is decreasing, and to return the second target acceleration to the first target acceleration more quickly.

[0065] Furthermore, in this embodiment, the control device 3 reduces the convergence speed when the rate of change of the accelerator opening is positive and the first target acceleration is increasing, compared to when the rate of change of the accelerator opening is approximately zero. This allows the second target acceleration to be slowly returned to the first target acceleration when the rate of change of the accelerator opening is positive and the first target acceleration is increasing, that is, when the vehicle 20 has a strong tendency to accelerate.

[0066] Furthermore, in this embodiment, when the adjusted second target acceleration reaches the first target acceleration, the control device 3 terminates the torque control of the drive source 1 based on the second target acceleration and starts the torque control of the drive source 1 based on the first target acceleration. This allows for the rapid commencement of normal acceleration control based on the first target acceleration after the second target acceleration converges.

[0067] [Differentiation] Thus, the embodiments described above are illustrative examples for explaining the present invention, and the present invention is not limited to these embodiments. The present invention can be implemented in various forms without departing from its spirit. [Explanation of symbols]

[0068] 1. Power source 3. Control device 5. Accelerator position sensor 7. Vehicle speed sensor 9. Accelerometer 10. Vehicle control system 20 vehicles

Claims

1. A vehicle control system, A drive source that generates the driving force of the vehicle, An accelerator position sensor that detects the accelerator position, which is the degree of opening of the accelerator pedal of the vehicle, A control device configured to control the drive source based on the accelerator opening detected by the accelerator opening sensor, It has, The control device is Determine a first target acceleration to be set according to the accelerator opening, and determine a second target acceleration set to be at least greater than the first target acceleration, and control the torque of the drive source based on the first target acceleration or the second target acceleration. During the control of the torque of the drive source based on the second target acceleration, when the rate of change of the accelerator opening decreases from an increasing state to a state of decreasing by a predetermined value or more, the second target acceleration is adjusted based on the first target acceleration and the rate of change of the accelerator opening to gradually converge to the first target acceleration, and the torque of the drive source is controlled based on the second target acceleration. A vehicle control system characterized by being configured in such a way.

2. The vehicle control system according to claim 1, wherein the control device is configured to determine a convergence speed for converging the second target acceleration to the first target acceleration based on the rate of change of the first target acceleration and the accelerator opening, and to adjust the second target acceleration based on the convergence speed.

3. The vehicle control system according to claim 2, wherein the control device is configured to increase the convergence speed when the rate of change of the accelerator opening is negative compared to when the rate of change of the accelerator opening is 0 or greater.

4. The vehicle control system according to claim 2, wherein the control device is configured to increase the convergence speed when the first target acceleration is decreasing compared to when the first target acceleration is increasing.

5. The vehicle control system according to claim 2, wherein the control device is configured to increase the convergence speed when the rate of change of the accelerator opening is positive and the first target acceleration is decreasing, compared to when the rate of change of the accelerator opening is approximately zero.

6. The vehicle control system according to claim 2, wherein the control device is configured to reduce the convergence speed when the rate of change of the accelerator opening is positive and the first target acceleration is increasing, compared to when the rate of change of the accelerator opening is approximately zero.

7. The control device is The control map includes a control map in which the convergence speed is defined in correspondence with the first target acceleration and the rate of change of the accelerator opening, The system is configured to determine the convergence speed corresponding to the current rate of change of the first target acceleration and the current accelerator opening from the control map, and to adjust the second target acceleration based on the convergence speed. A vehicle control system according to any one of claims 2 to 6.

8. The vehicle control system according to any one of claims 1 to 6, wherein the control device is configured to terminate the control of the torque of the drive source based on the second target acceleration and to start the control of the torque of the drive source based on the first target acceleration when the adjusted second target acceleration reaches the first target acceleration.

9. A vehicle having a drive source that generates driving force for the vehicle, an accelerator opening sensor that detects the accelerator opening, which is the opening degree of the accelerator pedal of the vehicle, and a control device configured to control the drive source based on the accelerator opening detected by the accelerator opening sensor, wherein a vehicle control method is performed by the control device, A step of determining a first target acceleration to be set according to at least the accelerator opening, and a second target acceleration set to be at least greater than the first target acceleration, and controlling the torque of the drive source based on the first target acceleration or the second target acceleration, During the control of the torque of the drive source based on the second target acceleration, when the rate of change of the accelerator opening decreases from an increasing state to a state of decreasing by a predetermined value or more, the second target acceleration is adjusted based on the first target acceleration and the rate of change of the accelerator opening to gradually converge to the first target acceleration, and the torque of the drive source is controlled based on the second target acceleration. A vehicle control method characterized by having the following:

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