Electronic control apparatus for vehicle

Abstract

To provide a control device for a vehicle improved in drivability during traveling on a rocky road.SOLUTION: A control device for a vehicle including a motor as a traveling power source comprises: a determination unit configured to determine whether or not a rocky road mode is selected as a traveling mode and vehicle speed is equal to or less than a threshold value; and a control unit configured to control the motor such that acceleration of the vehicle is more limited when a determination result of the determination unit is a positive determination than when the determination result of the determination unit is a negative determination.SELECTED DRAWING: Figure 2

Description

[Technical field]

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

[0002] There is a technique for making it easier to travel on rocky roads by increasing the driving force generated in a vehicle by an amount corresponding to the road surface gradient (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2015-030314 A Summary of the Invention [Problem to be solved by the invention]

[0004] When driving over rocks, vehicle speed and acceleration can fluctuate significantly, which can reduce drivability.

[0005] SUMMARY OF THE PRESENT DISCLOSURE An object of the present invention is to provide a vehicle control device that improves drivability when traveling on rocky roads. [Means for solving the problem]

[0006] The above object can be achieved by a control device for a vehicle equipped with a motor as a driving power source, comprising: a judgment unit that judges whether or not the rocky road mode is selected as the driving mode and the vehicle speed is below a threshold value; and a control unit that controls the motor so that the acceleration of the vehicle is more limited when the judgment result of the judgment unit is a positive judgment than when the judgment result of the judgment unit is a negative judgment. Effect of the Invention

[0007] According to the present invention, it is possible to provide a control device for a vehicle that improves drivability when traveling on rocky roads. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1A is a schematic configuration diagram of a hybrid vehicle, and FIG. 1B is a flowchart illustrating an example of acceleration limiting control executed by an ECU. [Diagram 2] FIG. 2A is a timing chart illustrating an example of traveling on a rocky road in the comparative example, and FIG. 2B is a timing chart illustrating an example of traveling on a rocky road in the present embodiment. [Diagram 3] FIG. 3A is an explanatory diagram of the acceleration when the hybrid vehicle climbs a rock, FIG. 3B is an explanatory diagram of the acceleration when the hybrid vehicle descends a rock, and FIG. 3C is a flowchart illustrating the acceleration selection control executed by the ECU. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] [General configuration of hybrid vehicle] 1A is a schematic diagram of a hybrid vehicle 1. The hybrid vehicle 1 is equipped with an engine 10 and motors M0 to M4 as a driving power source. The engine 10 is a gasoline engine having multiple cylinders, but may be a diesel engine. On a power transmission path from the engine 10 to the drive wheels 30, the engine 10 is provided with a motor M1, a clutch C1, a motor M2, a clutch C2, a torque converter 20, a transmission 22, a motor M3, and a motor M4 in this order. The motors M0 to M4 are supplied with electric power from a battery (not shown).

[0010] The motors M0 and M1 crank the engine 10 when the engine 10 is started, and assist the driving of the engine 10. The motor M0 is linked to the crankshaft of the engine 10 via a belt B. It is to be noted that only one of the motors M0 and M1 may be provided.

[0011] The motors M2 to M4 function as motors that generate driving force for the vehicle in response to power supply from the battery. The motors M2 to M4 also function as generators that generate electric power to charge the battery in response to power transmission from the engine 10 and the drive wheels 30. The motors M4 are in-wheel motors, and are provided on the drive wheels 30. Any one of the motors M2 to M4 may be provided.

[0012] The clutch C1 connects or disconnects the power transmission between the engine 10, the motor M0, or the motor M1 and the drive wheels 30 in response to the supply of hydraulic pressure. The clutch C2 connects or disconnects the power transmission between the engine 10, the motor M2, or the drive wheels 30 in response to the supply of hydraulic pressure. The torque converter 20 is a fluid coupling having a torque amplifying function. The transmission 22 is a stepped transmission that switches the gear ratio in multiple stages.

[0013] The hybrid vehicle 1 is provided with an ECU (Electronic Control Unit) 50 as a control device for the vehicle. The ECU 50 is an electronic control unit including a calculation processing circuit that performs various calculation processes related to the vehicle driving control, and a memory that stores control programs and data. The ECU 50 is an example of a control device for the vehicle, and functionally realizes a determination unit and a control unit, which will be described in detail later.

[0014] The ECU 50 is connected to a power switch S1, a driving mode selection switch S2, a vehicle speed sensor S3, a G sensor S4, a brake opening sensor S5, and an accelerator opening sensor S6. The power switch S1 is switched between a ready-off state and a ready-on state by being operated by the driver. The driving mode selection switch S2 is operated by the driver to select a driving mode suitable for the road surface conditions. Examples of driving modes suitable for the road surface conditions include a sandy road mode, a muddy road mode, and a rocky road mode. The vehicle speed sensor S3 detects the vehicle speed of the hybrid vehicle 1. The G sensor S4 detects the acceleration of the hybrid vehicle. The brake opening sensor S5 detects the opening of the brake pedal BP. The accelerator opening sensor S6 detects the opening of the accelerator pedal AP.

[0015] The ECU 50 controls the operation of the engine 10 and the motors M0 to M4. Specifically, the ECU 50 controls the operation of the engine 10 by adjusting the fuel injection amount and the intake air amount. The ECU 50 also controls the operation of the motors M0 to M4 by adjusting the amount of electric power exchanged between the motors M0 to M4 and the battery.

[0016] The ECU 50 runs the hybrid vehicle 1 in either motor running or hybrid running. In motor running, the ECU 50 releases the clutch C1 to rotate the drive wheels 30 with the power of at least one of the motors M2 to M4. In hybrid running, the ECU 50 engages the clutch C1 to rotate the drive wheels 30 with the power of at least the engine 10. For example, when the required driving force for the hybrid vehicle 1 reaches or exceeds a predetermined value, the drive mode is switched from motor running to hybrid running. Also, when the charge level of the battery falls below a predetermined value, the drive mode is switched from motor running to hybrid running.

[0017] [Acceleration Limit Control] Next, the acceleration limit control executed by the ECU 50 will be described. FIG. 1B is a flowchart illustrating the acceleration limit control executed by the ECU 50. First, the ECU 50 judges whether or not the rocky road mode is selected as the driving mode and the vehicle speed is equal to or lower than a threshold value (step S1). This process is an example of a process executed by a judgment unit. If the answer is No in step S1, this control ends. For example, if the rocky road mode is selected as the driving mode but the vehicle speed is higher than the threshold value, or if the vehicle speed is equal to or lower than the threshold value but a driving mode other than the rocky road mode is selected, the answer is No in step S1.

[0018] If the answer is Yes in step S1, the ECU 50 limits the acceleration of the hybrid vehicle 1 (step S2). The limit on the acceleration is realized by controlling the motors M0 to M4 so that the acceleration of the hybrid vehicle 1 is between an upper limit value and a lower limit value. The upper limit value is the maximum value when the hybrid vehicle 1 accelerates in the traveling direction. The lower limit value is the maximum value when the hybrid vehicle 1 decelerates in the traveling direction. Therefore, the upper limit value is a positive value and the lower limit value is a negative value. The above-mentioned threshold value is set to a vehicle speed that does not make the driver feel uncomfortable even if the acceleration is limited. This process is an example of a process executed by the control unit.

[0019] Next, traveling on a rocky road will be described. First, a comparative example will be described. FIG. 2A is a timing chart illustrating traveling on a rocky road in the comparative example. FIG. 2A shows the transitions of vehicle speed, acceleration, driving force, accelerator opening, and brake opening. When the accelerator pedal is depressed from a state in which the wheels hit a rock and the vehicle is stopped (time t1), the driving force increases, the acceleration increases, the wheels climb the rock, and the vehicle speed also increases. When the accelerator pedal is released and the brake pedal is depressed (time t2x) to stop the sudden acceleration, the driving force decreases and the acceleration and vehicle speed temporarily decrease, but the wheels start to descend the rock, so the acceleration and vehicle speed increase again. When the wheels descend the rock and the acceleration and vehicle speed decrease, the brake pedal is released (time t3x). In this way, the acceleration fluctuates greatly, and drivability decreases.

[0020] FIG. 2B is a timing chart illustrating the driving on a rocky road in this embodiment. FIG. 2B corresponds to FIG. 2A. In this embodiment, the above-mentioned acceleration limiting control is executed. When the accelerator pedal is depressed (time t1), the acceleration increases, but since it is more limited than in the comparative example, the driving force and the vehicle speed increase more slowly. Since the vehicle speed increases more slowly, the timing when the accelerator pedal is released and the brake pedal is depressed is later than in the comparative example (time t2). Also, since the vehicle speed is slower than in the comparative example, the brake opening is also smaller than in the comparative example. Even when the wheels go down the rock, the acceleration is limited, so the vehicle speed does not change much. Also, since the acceleration is limited even after the wheels go down the rock, the vehicle speed is maintained approximately constant even when the brake pedal is released (time t3). In this way, the fluctuation in acceleration is suppressed, and the drivability when driving on a rocky road is improved.

[0021] Incidentally, the acceleration limiting control may be performed during motor driving or hybrid driving. During motor driving, the ECU 50 limits the acceleration of the hybrid vehicle 1 by controlling at least one of the motors M2 to M4. During hybrid driving, the ECU 50 limits the acceleration of the hybrid vehicle 1 by performing regenerative operation on at least one of the motors M0 to M4 so as to become a load on the rotation of the engine 10. The acceleration limiting control may also be performed on an electric vehicle equipped with only a motor as a driving power source.

[0022] [Acceleration selection control] Furthermore, the ECU 50 executes acceleration selection control to select the acceleration when traveling on a rocky road. FIG. 3A is an explanatory diagram of the acceleration when the hybrid vehicle 1 climbs a rock. FIG. 3B is an explanatory diagram of the acceleration when the hybrid vehicle 1 descends a rock. The G-sensor 4 detects acceleration in the horizontal direction. Therefore, when the traveling direction of the hybrid vehicle 1 is inclined with respect to the horizontal direction, the magnitude of the acceleration in the traveling direction is greater than the magnitude of the acceleration in the horizontal direction. For example, when the hybrid vehicle 1 climbs a rock, the acceleration GA detected by the G-sensor 4 is +4 [m / s 2], the acceleration experienced by the driver will be greater than this value, for example +5[m / s 2 ]. In addition, the hybrid vehicle 1 decelerates when descending the rock, so the acceleration GA is -4 [m / s 2 ], the perceived acceleration is smaller than this value, for example, -5[m / s 2 Therefore, if the acceleration GA is used as the limiting target in the acceleration limiting control, the fluctuation of the perceived acceleration cannot be sufficiently suppressed, and drivability may deteriorate. Therefore, the ECU 50 executes the acceleration selection control to select one acceleration from among a plurality of accelerations as follows.

[0023] 3C is a flowchart illustrating the acceleration selection control executed by the ECU 50. The acceleration selection control is executed together with the acceleration limiting control. The ECU 50 calculates the accelerations MA and EA (step S11).

[0024] The acceleration MA is calculated based on the fluctuation of the rotation speed of the motor M4. The acceleration MA corresponds to the acceleration felt by the driver as described above. The acceleration MA is calculated as follows. Vehicle speed [km / h] = Motor M4 rotation speed [rpm] x tire circumference x 60 / 1000 The above vehicle speed [km / h] is converted to vehicle speed [m / s]. Next, the acceleration MA [m / s] is calculated by differentiating the vehicle speed [m / s] with respect to unit time. 2 The acceleration MA may be calculated based on the fluctuation in the rotation speed of the motor M2 or M3. However, from the viewpoint of calculation accuracy, it is preferable to calculate the acceleration MA based on the fluctuation in the rotation speed of the motor M4 that is closest to the drive wheels 30.

[0025] The acceleration EA is an internal value of the ECU 50 and is calculated by the ECU 50. The acceleration EA is calculated by the following formula. EA = (driving force - running resistance force) / vehicle weight The vehicle weight is pre-stored in the ROM of the ECU 50. The running resistance is calculated from the specifications of the hybrid vehicle 1. The driving force is, for example, a target driving force calculated according to the operating state of the hybrid vehicle 1. The acceleration EA is calculated as the acceleration in the horizontal direction.

[0026] Next, the ECU 50 determines whether the acceleration MA and the acceleration GA are substantially the same (step S12). Here, the acceleration MA and the acceleration GA do not need to exactly match. Even if there is a difference by a predetermined margin, the acceleration MA and the acceleration GA are determined to be the same. If Yes in step S12, the attitude of the hybrid vehicle 1 is regarded as being in a horizontal state, and the ECU 50 selects the acceleration MA or GA as the acceleration to be used for acceleration limit control (step S13).

[0027] If No in step S12, the ECU 50 determines whether the acceleration MA is greater than the acceleration GA (step S14). If Yes in step S14, the ECU 50 determines whether the acceleration MA is greater than the acceleration EA (step S15). If Yes in steps S14 and S15, the hybrid vehicle 1 is regarded as being in the process of climbing a rock, and the ECU 50 selects the acceleration MA as the acceleration to be used for acceleration limit control (step S16).

[0028] If No in step S14 or S15, the ECU 50 determines whether the acceleration MA is less than the acceleration EA (step S17). Here, for example, if No in step S14 and Yes in step S17, MA < GA and MA < EA are satisfied. In this case, the hybrid vehicle 1 is regarded as being in the process of descending a rock, and the ECU 50 selects the acceleration MA as the acceleration to be used for acceleration limit control (step S16). If Yes in step S14, No in step S15, and Yes in step S17, MA > GA and MA < EA are satisfied, and there is a possibility that the acceleration GA is an abnormal value. In this case, the hybrid vehicle 1 is regarded as being in the process of descending a rock, and the ECU 50 selects the acceleration MA as the acceleration to be used for acceleration limit control (step S16).

[0029] If the answer is No in steps S14 and S17, MA < GA and MA > EA hold, and there is a possibility that the acceleration MA is an abnormal value. In this case, the ECU 50 selects the acceleration GA instead of the acceleration MA as the acceleration to be used for the acceleration limit control (step S18). As described above, the acceleration suitable for the object to be limited in the acceleration limit control is selected. This further improves the drivability during driving on a rocky road.

[0030] As described above, the embodiments of the present invention have been described in detail. However, the present invention is not limited to such specific embodiments, and various modifications and changes are possible within the scope of the gist of the present invention described in the claims. [Explanation of Reference Numerals]

[0031] 1 Hybrid vehicle M0 to M4 Motors 50 ECU (Control device, determination unit, control unit)

Claims

[Claim 1] A control device for a vehicle equipped with a motor as a driving power source, a determination unit that determines whether or not a rocky road mode is selected as a driving mode and the vehicle speed is equal to or lower than a threshold; A control device for a vehicle comprising: a control unit that controls the motor so that the acceleration of the vehicle is more limited when the judgment result of the judgment unit is a positive judgment than when the judgment result of the judgment unit is a negative judgment.

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