Vehicle control device

Abstract

To provide a vehicle control device capable of selecting a noise vibration (NV) countermeasure suitable for a vehicle state and a user request.SOLUTION: A vehicle control device 15 controls a driving source 11, and a transmission 13 connected to the driving source 11 through a clutch 12, and includes driving force limit control means for executing driving force limit control of limiting the driving force of the driving source, on the basis of rotation speed of the driving source 11. In a state where the driving force limit control is executed by the driving force limit control means, when a request driving force required by a user operating a vehicle is higher than a driving force when being limited by the driving force limit control, the clutch is made in a slip state, and the rotation speed of the driving source 11 is increased.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a vehicle control device.

Background Art

[0002] Patent Document 1 discloses a vehicle control device that executes a control method of putting a clutch between an engine and a transmission in a slip state when the vehicle starts.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When a user drives a vehicle, improvement in drivability and riding comfort is always required, and countermeasures against cabin noise and vibration, that is, NV (Noise Vibration) countermeasures can be said to be an issue for the entire vehicle manufacturer.

[0005] Patent Document 1 discloses a vehicle control device that executes a control method of restricting the driving force of an engine by putting a clutch in a slip state when the vehicle starts. However, a control method of restricting the driving force of an engine in consideration of NV countermeasures may not reach the required driving force required by the user. Therefore, from the viewpoint of NV countermeasures, it can be said that the above control method leads to a decrease in drivability.

[0006] The present invention has been made to solve such problems, and an object thereof is to provide a vehicle control device capable of selecting NV countermeasures suitable for user requirements when accelerating a vehicle in a steady state.

Means for Solving the Problems

[0007] The vehicle control device according to the present invention is a vehicle control device that controls a transmission connected to a drive source via a clutch, and includes a driving force limit control means for performing a driving force limit control that limits the driving force of the drive source based on the rotational speed of the drive source. When the required driving force requested by a user operating the vehicle is higher than the driving force limited by the driving force limit control in a state where the driving force limit control is executed by the driving force limit control means, the clutch is set in a slip state and the rotational speed of the drive source is increased.

Effect of the Invention

[0008] According to the present invention, it is possible to provide a vehicle control device capable of selecting an NV countermeasure suitable for a user request when accelerating a vehicle in a steady state.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Modes for Carrying Out the Invention

[0010] <Embodiment 1> Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows the configuration of a vehicle equipped with the vehicle control device according to the present embodiment. The vehicle 10 according to the present embodiment includes a drive source 11, a clutch 12, a transmission 13, drive wheels 14, and a vehicle control device 15. The drive source 11 is connected to the transmission 13 via the clutch 12.

[0011] The vehicle control device 15 includes a driving force control means that executes driving force limit control for providing a limit to the driving force of the drive source 11 based on the rotational speed of the drive source 11.

[0012] FIG. 2 shows the processing executed by the vehicle control device 15 according to the present embodiment. First, information on the running state of the vehicle and user requests is acquired (S101). Next, a required driving force requested by the user for the vehicle is calculated from the acquired information on the running state of the vehicle and user requests (S102).

[0013] Here, it is determined whether the rotational speed of the engine functioning as the drive source 11 is within the range of a target region (hereinafter referred to as the “NV constraint region”) that requires constraints for NV countermeasures (S103). The NV constraint region is a region set in advance based on the rotational speed and torque of the engine, and details will be described later. Also, when the rotational speed is outside the range of the NV constraint region, driving in the normal control mode is continued.

[0014] Next, when the rotational speed is within the range of the NV constraint region, it is determined whether the required driving force can be achieved taking NV countermeasures into account (S104). Here, when the required driving force can be achieved under the condition that the driving force is limited by the NV countermeasures, driving in the normal control mode is continued.

[0015] And when the required driving force requested by the user cannot be achieved under the condition that the driving force is limited by the NV countermeasures, the clutch 12 is put into a slip state and a transition is made to a high driving force mode for achieving the required driving force (S105).

[0016] In this way, even in a situation where the user requests a driving force greater than the driving force after the limit while the driving force is limited for NV countermeasures, the rotational speed of the engine functioning as the drive source 11 can be increased, so that a desired driving force can be ensured. Therefore, according to the present invention, it is possible to provide a vehicle control device capable of selecting an NV countermeasure suitable for user requests when accelerating a vehicle in a steady state.

[0017] Furthermore, the control by the vehicle control device will be specifically described.

[0018] The vehicle control device 15 shown in FIG. 1 is capable of executing control processes such as output control of the engine functioning as the drive source 11, engagement state control of the clutch 12, and shift control of the transmission 13. Further, as the clutch 12 for transmitting the power from the drive source 11 to the drive wheel 14 side, a wet or dry engagement device is used.

[0019] In step S101 shown in FIG. 2, information on the running state of the vehicle is acquired by detecting the speed, gradient, weight, engine speed, etc. of the vehicle. Information on the user request is acquired by detecting the accelerator opening, etc. determined by the amount of depression of the accelerator pedal when the user operates the vehicle.

[0020] Here, the running state of the vehicle will be described with reference to FIGS. 3(a), (b), and (c). FIGS. 3(a), (b), and (c) are time charts showing the respective characteristics representing the running state of the vehicle according to the present embodiment.

[0021] FIG. 3(a) is a time chart with the accelerator opening on the vertical axis. From the steady state, that is, the state where the vehicle is stopped or running at a constant speed, the user depresses the accelerator pedal according to the degree of accelerating the vehicle. The vehicle control device 15 determines the accelerator opening based on this depression amount.

[0022] FIG. 3(b) is a time chart with the increase amount of the vehicle speed on the vertical axis. It shows that as the accelerator opening increases, the vehicle accelerates from the steady state and the speed increases. The solid line in the figure shows the increase amount of the speed when transitioning to the high driving force mode according to step S105 shown in FIG. 2. The dotted line in the figure shows the increase amount of the speed when continuing to run with the driving force limited according to the NV constraint region, that is, a comparative example. It can be seen that the increase amount of the speed, that is, the acceleration, is lower as the accelerator opening increases compared to the high driving force mode executed in the control according to the present embodiment.

[0023] FIG. 3(c) is a time chart with the vertical axis representing the engine speed of the engine functioning as the drive source 11 and the input speed of the automatic transmission AT (Automatic Transmission) functioning as the transmission 13 that transmits the power from the drive source 11 to the drive wheels 14.

[0024] Similar to FIG. 3(b), the solid line in the figure indicates the speed when transitioning to the high driving force mode, and the dotted line in the figure indicates the speed when the driving force is limited according to the NV constraint region. Also, the dashed-dotted line in the figure represents the critical point of the NV constraint. Therefore, the region with a lower speed below the dashed-dotted line represents the NV constraint region.

[0025] As shown in FIG. 3(c), the AT input speed hardly changes due to the transition to the high driving force mode. On the other hand, it can be seen that the engine speed increases due to the transition to the high driving force mode. This is because by transitioning to the high driving force mode and setting the clutch 12 in a slip state, the engine speed can be increased while maintaining the AT input speed.

[0026] Next, the operation of the engine functioning as the drive source of the vehicle equipped with the vehicle control device according to the present embodiment and the NV constraint region will be specifically described.

[0027] FIG. 4 schematically shows the operation of the vehicle engine, with the engine speed on the horizontal axis and the torque output by the engine on the vertical axis. The solid line in the figure represents the maximum value of the torque that can be generated at the engine speed at which the engine operates most efficiently, i.e., the maximum torque. Also, similar to FIG. 3(c), the dashed-dotted line in the figure represents the critical point of the NV constraint. The NV constraint region is a region set in advance by experiments or the like based on the engine speed and torque.

[0028] In FIG. 4, the region 101 between the solid line and the dashed-dotted line is a region where, although there is no problem in the operation of the engine, there are stuffy noises and vibrations to such an extent that a decrease in drivability is recognized. Therefore, it is a region that is not permitted to be used from the perspective of NV countermeasures.

[0029] The region 102 below the dashed-dotted line is a region where stable driving is possible from the perspective of NV countermeasures. However, as represented by the difference between the required operating point 201 indicating the required driving force demanded by the user for the vehicle and the current operating point 202 indicating the actual driving force, the actual driving force does not reach the required driving force, and particularly, it is a region where the torque required for vehicle acceleration is insufficient.

[0030] In order to ensure high torque while maintaining the engine speed within the range of the NV constraint region, step S105 shown in FIG. 2 is executed. Specifically, the clutch is switched from the engaged state to the slip state, and the engine speed is increased.

[0031] After that, while maintaining the torque and speed within the range of the NV constraint region, when the torque is secured up to the high driving force mode operating point 203 that reaches the maximum torque corresponding to the engine speed (region 103), the clutch is returned from the slip state to the engaged state.

[0032] In this way, even in a situation where the driving force is limited for NV countermeasures and the user demands more driving force, since the engine speed can be increased, it becomes possible to secure the desired driving force. That is, it becomes possible to maintain drivability and ride comfort while satisfying the required driving force.

[0033] Note that the present invention is not limited to the above-described embodiments, and can be appropriately modified without departing from the gist thereof.

Explanation of Reference Numerals

[0034] 10 Vehicle 11 Drive source 12 Clutch 13 Transmission 14 Driving wheel 15 Vehicle control device 101 Area 102 Area 103 Area 201 Required operating point 202 Current operating point 203 High driving force mode operating point

Claims

【Claim 1】 A vehicle control device that controls a transmission connected to a drive source via a clutch, the vehicle control device comprising: driving force limit control means for performing driving force limit control to limit the driving force of the drive source based on the rotational speed of the drive source; The driving force limit control means: acquires information on the running state of the vehicle and the user's request of the user operating the vehicle; calculates a required driving force requested by the user operating the vehicle from the running state and the user request; determines whether the rotational speed of the drive source is within a predetermined range, and if the rotational speed is outside the predetermined range, continues to run in the normal control mode; if the rotational speed is within the predetermined range, sets the driving force limit control to be executed; In this state, if the required driving force is lower than the driving force limited by the driving force limit control, continues to run in the normal control mode; if the required driving force is higher than the driving force limited by the driving force limit control, sets the clutch in a slip state, increases the rotational speed of the drive source, and transitions to a high driving force mode; is configured to return the clutch from the slip state to the engaged state after securing the torque up to the point where the maximum torque corresponding to the rotational speed is reached while maintaining the torque and the rotational speed of the vehicle within the predetermined range; the required driving force is calculated based on the speed, gradient, weight, engine rotational speed of the vehicle, and the accelerator opening determined by the amount of depression of the accelerator pedal when the user operates the vehicle; the predetermined range is a range set in advance based on the drive source and the torque of the vehicle; A vehicle control device.

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