Control device of vehicle

Abstract

To suppress a driver from feeling strange due to rapid increase of rotation speed by restriction control, in a running state where an accelerator is not operated.SOLUTION: A control device performs charging control of charging a battery with electricity by regenerative braking in a running state where an accelerator is not operated, and restriction control of restricting the charging control in the running state where the accelerator is not operated. When performing the restriction control, the control device increases rotation speed RS of a crank shaft up to first predetermined rotation speed and does not perform the charging by the charging control, when a charging rate SOC reaches an upper limit value UL. When performing the restriction control, the control device increases rotation speed of the crank shaft up to second predetermined rotation speed RS2 and performs charging at amounts of charge per unit time by the charging control that are smaller than when the restriction control is not performed, when the charging rate SOC is equal to a specified rate THR or more and less than the upper limit value UL.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] Patent Document 1 describes a vehicle equipped with an internal combustion engine, a motor generator as a regenerative braking device, and a battery. The vehicle's control device performs charge control to charge the battery by regenerative braking, in which the regenerative braking device applies regenerative braking force to the wheels. When the battery's charge rate reaches an upper limit, the vehicle's control device performs limit control to control charge by increasing the rotational speed of the crankshaft to a predetermined rotational speed, thereby not performing charge control. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-202559 Summary of the Invention [Problem to be solved by the invention]

[0004] In a vehicle such as that described in Patent Document 1, if limit control is performed while the vehicle is running and the accelerator is not being operated, such as during cruise control, the rotational speed of the crankshaft may rise suddenly to a predetermined rotational speed, which may make the driver feel uncomfortable. [Means for solving the problem]

[0005] In order to solve the above problems, the present invention is applied to a vehicle that includes an internal combustion engine, a regenerative braking device that can apply a regenerative braking force to a wheel in accordance with torque transmitted from the wheel, and a battery that is charged with electric power generated by regenerative braking in which the regenerative braking force is applied to the wheel, and includes a charging control that charges the battery by the regenerative braking in a running state in which no accelerator operation is performed, and a braking force is applied to the wheel by rotating a crankshaft of the internal combustion engine by the torque transmitted from the wheel in a running state in which no accelerator operation is performed, and and limiting control that limits charging by the charging control by an amount corresponding to the torque that rotates the crankshaft, wherein, when performing the limiting control, when the charging rate of the battery reaches an upper limit, the rotation speed of the crankshaft is increased to a first predetermined rotation speed, and when the charging rate of the battery is equal to or greater than a specified rate that is smaller than the upper limit and is less than the upper limit without charging by the charging control, the rotation speed of the crankshaft is increased to a second predetermined rotation speed that is smaller than the first predetermined rotation speed, thereby reducing the amount of charge per unit time by the charging control compared to when the limiting control is not performed.

[0006] According to the above configuration, when the vehicle is traveling without accelerator operation and the charging rate is equal to or greater than the specified rate but less than the upper limit, the rotation speed is limited to the second predetermined rotation speed without increasing to the first predetermined rotation speed. This prevents a sudden increase in the rotation speed. This prevents the driver from feeling uncomfortable due to a sudden increase in the rotation speed. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic diagram showing a vehicle. [Figure 2] FIG. 2 is a flowchart showing a series of processes including the limit control. DETAILED DESCRIPTION OF THE INVENTION

[0008] (One embodiment) Hereinafter, an embodiment of a vehicle control device will be described with reference to the drawings. <Vehicle Overview> 1, a vehicle 500 includes an internal combustion engine 10, a power distribution integration mechanism 40 connected to a crankshaft 14 that is an output shaft of the internal combustion engine 10, and a first motor generator 71 and a second motor generator 72 connected to the power distribution integration mechanism 40. The second motor generator 72 is a regenerative braking device that can apply regenerative braking force to the wheels 62 in accordance with the torque transmitted from the wheels 62.

[0009] The power distribution integration mechanism 40 is a planetary gear mechanism and includes a sun gear 41, which is an external gear, and a ring gear 42, which is an internal gear. The sun gear 41 is located at the center of the ring gear 42. The sun gear 41 rotates coaxially with the ring gear 42. A plurality of pinion gears 43 are interposed between the sun gear 41 and the ring gear 42. Each pinion gear 43 meshes with both the sun gear 41 and the ring gear 42. Each pinion gear 43 is supported by a carrier 44 in a state where it can rotate on its own axis and revolve around the sun gear 41. The carrier 44 rotates coaxially with the sun gear 41 as the pinion gear 43 revolves.

[0010] The sun gear 41 is connected to the first motor generator 71. That is, the sun gear 41 is adapted to operate in conjunction with the first motor generator 71. The carrier 44 is connected to the crankshaft 14. That is, the carrier 44 is adapted to operate in conjunction with the crankshaft 14. The ring gear 42 is connected to a ring gear shaft 45. The ring gear shaft 45 is connected to the second motor generator 72 via a reduction gear 50. That is, the ring gear shaft 45, and therefore the ring gear 42, are adapted to operate in conjunction with the second motor generator 72. The ring gear shaft 45 is connected to left and right wheels 62 via a reduction mechanism 60 and a differential 61. That is, the ring gear shaft 45, and therefore the ring gear 42, are adapted to operate in conjunction with the wheels 62.

[0011] The reduction gear 50 is a planetary gear mechanism. That is, the reduction gear 50 includes a ring gear 52 which is an internal gear, a sun gear 51 which is an external gear, and a plurality of pinion gears 53 located between the sun gear 51 and the ring gear 52. Each pinion gear 53 is rotatable on its own axis but is supported in a state where it cannot revolve around the sun gear 51.

[0012] The vehicle 500 is equipped with a first inverter 76, a second inverter 77, and a battery 78. The first inverter 76 and the second inverter 77 convert AC / DC power between each motor generator and the battery 78 and adjust the amount of power exchanged. Therefore, the battery 78 is charged with power generated by regenerative braking, in which regenerative braking force is applied to the wheels 62. The vehicle 500 is equipped with a hydraulic brake 79. The hydraulic brake 79 applies hydraulic pressure to output braking force as torque that suppresses rotation of the wheels 62.

[0013] The vehicle 500 is equipped with an accelerator sensor 91, a vehicle speed sensor 92, a brake temperature sensor 93, a battery sensor 94, and a switch 95. The accelerator sensor 91 detects an accelerator operation amount ACC, which is the amount of depression of the accelerator pedal in the vehicle 500. The vehicle speed sensor 92 detects a vehicle speed SP, which is the traveling speed of the vehicle 500. The brake temperature sensor 93 detects a brake temperature TB, which is the temperature of the brake pads of the hydraulic brakes 79. The battery sensor 94 detects battery information VI, including the amount of current, voltage, etc. of the battery 78. The switch 95 is operated by a user to detect an operation signal SC, which indicates whether cruise control for the vehicle 500 is requested or canceled.

[0014] <Control device> The vehicle 500 is equipped with a control device 100. The control device 100 acquires, from each sensor, a signal indicating an accelerator operation amount ACC, a signal indicating a vehicle speed SP, a signal indicating a brake temperature TB, a signal indicating battery information VI, and an operation signal SC indicating a request for or cancellation of cruise control.

[0015] The control device 100 calculates the vehicle's required driving force, which is a required value of driving force necessary for the vehicle 500 to travel, based on the accelerator operation amount ACC and the vehicle speed SP. The control device 100 determines the torque distribution among the internal combustion engine 10, the first motor generator 71, and the second motor generator 72 based on the vehicle's required driving force. The control device 100 controls the output of the internal combustion engine 10 and the power running and regeneration of the first motor generator 71 and the second motor generator 72 based on the determined torque distribution. The control device 100 also controls the first motor generator 71 via the first inverter 76 by outputting a control signal to the first inverter 76. The control device 100 also controls the second motor generator 72 via the second inverter 77 by outputting a control signal to the second inverter 77.

[0016] Furthermore, when the vehicle 500 is traveling, the control device 100 selects either the EV mode or the HV mode as the traveling mode of the vehicle 500. Here, the EV mode is a traveling mode in which the first motor generator 71 and the second motor generator 72 are driven to travel the vehicle 500 while the internal combustion engine 10 is stopped. Furthermore, the HV mode is a traveling mode in which the internal combustion engine 10 is driven in addition to the first motor generator 71 and the second motor generator 72 to travel the vehicle 500.

[0017] When the control device 100 receives a signal indicating that cruise control has been requested, it controls the vehicle 500 to be in a traveling state with no accelerator operation and to be within a predetermined vehicle speed SP.

[0018] The control device 100 performs charging control to charge the battery 78 by regenerative braking. In particular, the control device 100 applies a regenerative braking force to the wheels 62 in accordance with the torque transmitted from the wheels 62 by controlling the second motor generator 72 while the vehicle is running with no accelerator operation. The control device 100 also charges the battery 78 with electric power generated by the second motor generator 72 by the regenerative braking force. For example, the control device 100 performs charging control when the vehicle 500 is decelerated.

[0019] The control device 100 performs limiting control to limit charging by charge control. Specifically, in a running state where the accelerator is not being operated, the control device 100 controls the first motor generator 71 to rotate the crankshaft 14 by the torque transmitted from the wheels 62, thereby applying a braking force to the wheels 62. In this way, the control device 100 ensures deceleration by using the torque that rotates the crankshaft 14, out of the torque transmitted from the wheels 62.

[0020] 2, the control device 100 repeatedly executes a series of processes including limit control at a predetermined cycle. When the control device 100 starts the series of processes, it first executes the process of step S11.

[0021] In step S11, the control device 100 determines whether or not the vehicle is in a driving state where the accelerator pedal is not being operated. Specifically, the control device 100 determines that the vehicle is in a driving state where the accelerator pedal is not being operated when an operation signal SC indicating a request for cruise control is input and the acquired accelerator operation amount ACC indicates zero. If the vehicle is not in a driving state where the accelerator pedal is not being operated (S11: NO), the control device 100 ends the series of processes. On the other hand, if the vehicle is in a driving state where the accelerator pedal is not being operated (S11: YES), the control device 100 proceeds to step S12.

[0022] In step S12, the control device 100 determines whether the state of charge SOC is equal to or greater than a specified rate THR. Specifically, the control device 100 calculates the state of charge SOC based on the acquired battery information VI. The control device 100 compares the calculated state of charge SOC with the specified rate THR. The specified rate THR is determined in advance through testing, simulation, or the like as a value that is smaller than the upper limit value UL but indicates a sufficiently high state of charge SOC. If the state of charge SOC is less than the specified rate THR (S12: NO), the control device 100 ends the series of processes. On the other hand, if the state of charge SOC is equal to or greater than the specified rate THR (S12: YES), the control device 100 proceeds to step S13.

[0023] In step S13, the control device 100 determines whether the state of charge SOC is less than an upper limit value UL. The upper limit value UL is determined in advance through tests, simulations, etc. as a value that indicates that the state of charge SOC has become so high that the battery 78 cannot be charged. If the state of charge SOC is equal to or greater than the upper limit value UL (S13: NO), the control device 100 proceeds to step S21.

[0024] In step S21, the control device 100 performs limit control. During the limit control in step S21, the control device 100 increases the rotation speed RS of the crankshaft 14 to a first predetermined rotation speed RS1, and does not perform charging through charge control. The first predetermined rotation speed RS1 is determined in advance through testing, simulation, or the like as a speed at which all of the torque transmitted from the wheels 62 can be consumed as torque to rotate the crankshaft 14. Thereafter, the control device 100 ends the series of processes.

[0025] On the other hand, when the state of charge SOC is less than the upper limit value UL (S13: YES), the control device 100 proceeds to step S14. In step S14, the control device 100 determines whether the vehicle 500 will continue traveling with an increasing state of charge SOC. Specifically, the control device 100 determines whether the vehicle 500 is traveling downhill and whether the downhill traveling will continue for a predetermined distance or more, based on the traveling position, traveling history, and map information of the vehicle 500. When the vehicle 500 is required to travel at a constant vehicle speed SP by cruise control and the downhill traveling continues for a predetermined distance or more, there is a high probability that the charging control will continue for a corresponding period of time. Therefore, when the vehicle 500 continues traveling downhill for a predetermined distance or more, the control device 100 determines that the vehicle 500 will continue traveling with an increasing state of charge SOC. When the control device 100 determines that the vehicle 500 will not continue traveling with an increasing state of charge SOC (S14: NO), the control device 100 ends the series of processes. On the other hand, when it is determined that the driving that causes the state of charge SOC to increase will continue (S14: YES), the control device 100 advances the process to step S15.

[0026] In step S15, the control device 100 performs limit control. During the limit control in step S15, the control device 100 increases the rotation speed RS of the crankshaft 14 to a second predetermined rotation speed RS2 and performs charge control. The second predetermined rotation speed RS2 is determined in advance through testing, simulation, or the like as a rotation speed RS lower than the first predetermined rotation speed RS1. When performing charge control, the higher the rotation speed RS of the crankshaft 14 set by the limit control, the greater the power consumed by rotating the crankshaft 14 without charging. Therefore, the limit control in step S15 reduces the power consumed by the limit control compared to when the limit control in step S21 is performed. On the other hand, the limit control in step S15 reduces the amount of charge by the amount of torque that rotates the crankshaft 14 compared to when the limit control is not performed. After that, the control device 100 proceeds to step S16.

[0027] In step S16, the control device 100 determines whether the brake temperature TB is equal to or lower than a specified temperature THT. The specified temperature THT is determined in advance through testing, simulation, or the like as the temperature at which braking force cannot be generated due to the fade phenomenon. If the brake temperature TB is lower than the specified temperature THT (S16: NO), the control device 100 ends the series of processes. On the other hand, if the brake temperature TB is equal to or higher than the specified temperature THT (S16: YES), the control device 100 proceeds to step S17.

[0028] In step S17, the control device 100 controls the hydraulic brake 79 to output a braking force by the hydraulic brake 79 in accordance with the vehicle speed SP. Thereafter, the control device 100 ends the series of processes.

[0029] <Actions and Effects of the Embodiment> According to the above embodiment, when the state of charge SOC is equal to or greater than the specified rate THR and less than the upper limit UL while the accelerator is not being operated, the rotation speed RS is limited to the second predetermined rotation speed RS2 rather than the first predetermined rotation speed RS1. This prevents a sudden increase in the rotation speed RS. Therefore, it is possible to prevent the driver from feeling uncomfortable due to a sudden increase in the rotation speed RS. In particular, when driving in EV mode, the driver is likely to feel uncomfortable due to an increase in the rotation speed RS, so the effect of this control is more likely to be achieved. Furthermore, when the state of charge SOC is less than the upper limit UL, the charge amount per unit time through the charge control is reduced compared to when the limit control is not performed. Therefore, the time until the state of charge SOC reaches the upper limit UL can be longer compared to when the limit control is not performed. As a result, for example, the charge control may be terminated before the state of charge SOC reaches the upper limit UL, for example, due to the end of downhill driving. In this case, it is possible to avoid increasing the rotation speed RS to the first predetermined rotation speed RS1.

[0030] (Other embodiments) In step S14, the control device 100 may determine whether or not the driving that increases the charging rate SOC will continue based on the transition of the charging rate SOC, the amount of power generation, the regenerative braking force, map information, and data on past charging rate SOC.

[0031] In step S16, the control device 100 may determine whether or not to output a braking force from the hydraulic brake 79 based on the braking force output by the hydraulic brake 79 and the time during which the hydraulic brake 79 outputs the braking force, instead of the brake temperature TB.

[0032] In addition to step S15 and step S21, the control device 100 may start control to consume power. For example, the control device 100 may turn on the heater of the vehicle 500 or the air conditioner of the vehicle 500. This can suppress an increase in the state of charge (SOC) due to the consumption of power from the battery 78. [Explanation of symbols]

[0033] 10...internal combustion engine, 14...crankshaft, 62...wheel, 71...first motor generator, 72...second motor generator, 78...battery, 100...control device, 500...vehicle

Claims

[Claim 1] The present invention is applied to a vehicle including an internal combustion engine, a regenerative braking device capable of applying a regenerative braking force to a wheel in accordance with torque transmitted from the wheel, and a battery that is charged with electric power generated by regenerative braking in which the regenerative braking force is applied to the wheel, charging control for charging the battery by the regenerative braking in a running state in which the accelerator pedal is not operated; a limiting control that applies a braking force to the wheels by rotating a crankshaft of the internal combustion engine using torque transmitted from the wheels in a running state in which an accelerator pedal is not operated, and that limits charging by the charging control by an amount of torque that rotates the crankshaft out of the torque transmitted from the wheels, When performing the limit control, When the charging rate of the battery reaches an upper limit, the rotation speed of the crankshaft is increased to a first predetermined rotation speed, and charging is not performed by the charging control. When the charging rate of the battery is equal to or higher than a specified rate that is lower than the upper limit value and is lower than the upper limit value, the rotation speed of the crankshaft is increased to a second predetermined rotation speed that is lower than the first predetermined rotation speed, and the amount of charge per unit time due to the charge control is reduced compared to when the limit control is not performed. Vehicle control device.

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