Travel control device for vehicle, travel control method, and storage medium

Abstract

The present disclosure relates to a travel control device for a vehicle, a travel control method, and a storage medium. A travel control device mounted on a vehicle equipped with an electric motor and an internal combustion engine as a power source is provided. The travel control device includes a first acquisition unit that acquires a destination point of the vehicle, a second acquisition unit that acquires a past travel history from a departure point to the destination point, a third acquisition unit that acquires a target state of charge, an estimation unit that estimates an expected amount of generated energy based on the travel history, the generated energy being energy that can be generated in the vehicle until the vehicle reaches the destination point, a setting unit that sets a first section and a second section based on the expected amount of generated energy and the target state of charge, and a control unit that controls travel of the vehicle based on the first section and the second section.

Description

Technical Field

[0001] This disclosure relates to a driving control device installed on a vehicle, etc. Background Technology

[0002] In hybrid vehicles equipped with both an electric motor and an internal combustion engine, fuel consumption can be improved by effectively using the driving control of both the electric motor and the internal combustion engine.

[0003] Japanese Patent No. 4702086 (JP 4702086 B) discloses a vehicle driving assistance device that, based on the vehicle's location and map information such as necessary stopping or deceleration points at railway crossings and curves, notifies the driver of the braking initiation point when regenerative braking operation needs to be started. In this vehicle driving assistance device, the driver is encouraged to apply regenerative braking at a deceleration level that allows for efficient recovery of regenerative energy, thereby increasing the amount of regenerative energy recovered. Summary of the Invention

[0004] In the technology described in JP 4702086 B, it is possible to predict the locations where renewable energy can be expected to be recovered, but the amount of renewable energy to be recovered cannot be quantitatively predicted. Therefore, if the amount of renewable energy to be recovered can be quantitatively predicted at an early stage, the energy that can be generated in the vehicle, including that renewable energy, can be effectively estimated and used for appropriate driving control.

[0005] This disclosure is made in view of the above-mentioned problems, and the purpose of this disclosure is to provide a driving control device for a vehicle, etc., capable of predicting a quantitative amount of energy, including recovered regenerative energy, that can be generated in the vehicle and using it for driving control.

[0006] To address the aforementioned problems, the disclosed technical solution is a driving control device installed on a vehicle equipped with an electric motor and an internal combustion engine as power sources. The driving control device includes: a first acquisition unit that acquires the vehicle's destination location; a second acquisition unit that acquires past driving history from a departure point to the destination; a third acquisition unit that acquires a target energy storage rate, which is the energy storage rate of the battery installed in the target vehicle at the time the vehicle arrives at the destination; an estimation unit that estimates an expected amount of generated energy based on the driving history, the generated energy being the energy that can be generated in the vehicle until the vehicle arrives at the destination; a setting unit that sets a first interval and a second interval based on the expected amount of generated energy and the target energy storage rate, the first interval being an interval that drives only the electric motor for driving, and the second interval being an interval that drives at least the internal combustion engine for driving; and a control unit that controls the driving of the vehicle based on the first interval and the second interval.

[0007] According to the present disclosure, a driving control device for a vehicle can estimate the expected amount of energy that can be generated in the vehicle based on past vehicle driving history, and achieve appropriate driving control based on the estimated expected amount of energy, taking into account the target energy storage rate of the battery. Attached Figure Description

[0008] The features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will now be described with reference to the accompanying drawings, wherein like reference numerals denote like elements, and wherein:

[0009] Figure 1 This is a functional block diagram of a driving control device and its peripheral components according to embodiments of the present disclosure;

[0010] Figure 2A This is a flowchart illustrating an example of driving control processing performed by the driving control device;

[0011] Figure 2B This is a flowchart illustrating an example of driving control processing performed by the driving control device;

[0012] Figure 3A This is a flowchart illustrating an example of driving scenario generation processing performed by the driving control unit;

[0013] Figure 3B This is a flowchart illustrating an example of driving scenario generation processing performed by the driving control unit;

[0014] Figure 4 This is a flowchart illustrating an example of threshold modification processing performed by the driving control unit;

[0015] Figure 5 This is a graph showing an example of a driving power curve;

[0016] Figure 6 This is a diagram showing the regenerative energy region in the driving power curve;

[0017] Figure 7 This is a graph showing an example of a velocity curve;

[0018] Figure 8 It is a diagram showing the region in the speed curve where electricity can be generated;

[0019] Figure 9 This is a graph illustrating an example of changes in battery capacity (without a target capacity).

[0020] Figure 10 This is a graph showing an example of changes in the battery's charge storage capacity (including the target charge storage capacity);

[0021] Figure 11This is a diagram illustrating an example of a method for determining a threshold (with a limit on the allowed upper limit value); and

[0022] Figure 12 This is a diagram illustrating an example of a method for determining a threshold (with limitations on the allowed lower limit value). Detailed Implementation

[0023] The driving control device according to this embodiment uses a driving power curve and a speed curve to quantitatively estimate the energy that can be generated in the vehicle in an early stage. The driving power curve is a time series of the expected changes in driving power generated by the power source during driving from the starting point to the destination, and the speed curve is a time series of the changes in vehicle speed. This makes it possible to use the results of the estimation to provide appropriate driving control that takes into account the target battery charge rate.

[0024] In the following description, embodiments of the present disclosure will be described with reference to the accompanying drawings.

[0025] Example

[0026] Configuration

[0027] Figure 1 This is a functional block diagram illustrating a driving control device 10 and its peripheral components according to an embodiment of the present disclosure. The driving control device 10 is mounted on a vehicle. Figure 1 As shown, in addition to the driving control unit 10, the vehicle is equipped with a configuration including an internal combustion engine electronic control unit (ECU) 20, an internal combustion engine 21, a transmission 22, an electric motor ECU 30, an electric motor 31, a battery ECU 40, a battery 41, an electric power steering (EPS) ECU 50, an EPS device 51, a braking ECU 60, a braking device 61, a driving control ECU 70, a driver assistance ECU 80, an automatic driving ECU 90, a management ECU 100, a storage unit 110, and a communication unit 120. The driving control unit 10 is connected to these configurations via an in-vehicle network 200, such as a controller area network (CAN) or Ethernet (registered trademark), to enable communication between them.

[0028] In addition to the above configurations, various sensors such as accelerator pedal sensors, brake pedal sensors, cameras and other obstacle sensors, vehicle speed sensors, yaw rate sensors and global positioning system (GPS) sensors, as well as various devices such as navigation systems, can be installed on the vehicle, but are not shown in the accompanying drawings of this disclosure.

[0029] The internal combustion engine 21 and the electric motor 31 are actuators (ACTs) used as power sources to drive the vehicle. The electric motor 31 is also a generator that generates electricity through regenerative braking during vehicle deceleration and downhill driving, as well as a braking device that generates braking force.

[0030] The internal combustion engine ECU 20 is an electronic control unit (ECU) that controls the internal combustion engine 21 and the transmission 22. It performs control by changing the speed between the input and output to generate drive torque and braking torque through engine braking.

[0031] The electric motor ECU 30 is an electronic control unit that controls the electric motor 31 to perform control to generate drive torque and braking torque through regenerative braking.

[0032] Battery 41 is a rechargeable secondary battery (e.g., lithium-ion, nickel-metal hydride, and lead-acid battery) that can supply power to electric motor 31 and other devices by discharging, and can be charged with power obtained through regenerative braking of electric motor 31 (recovered energy) or power obtained through power operation of internal combustion engine 21 (generated energy). Battery ECU 40 is an electronic control unit that controls the charging and discharging of battery 41.

[0033] The electric power steering (EPS) device 51 is an actuator that steers the vehicle by changing the steering angle of the wheels. The EPS ECU 50 is an electronic control unit that controls the EPS device 51.

[0034] The braking device (foot brake) 61 is an actuator that generates braking force through friction on a component that rotates with the wheel. The brake ECU 60 is an electronic control unit that controls the braking device 61.

[0035] The driving control ECU 70 is an electronic control unit that controls the internal combustion engine ECU 20 and the electric motor ECU 30 according to the following driving modes.

[0036] The driver assistance ECU 80 is an electronic control unit that performs various functions such as collision avoidance (PCS), adaptive cruise control (ACC), lane keeping assist (LKA), and lane departure warning (LDW) to assist in driving the vehicle. The driver assistance ECU 80 outputs commands based on vehicle information obtained from various sensors to control vehicle movement such as acceleration / deceleration and steering angle. The functions and number of driver assistance ECUs 80 are unlimited.

[0037] The autonomous driving ECU 90 is an electronic control unit that performs autonomous driving functions. In order to perform autonomous driving functions, the autonomous driving ECU 90 outputs commands based on vehicle information obtained from various sensors to control the vehicle's movement, such as acceleration / deceleration and steering angle.

[0038] The management ECU 100 is an electronic control unit that issues commands to the EPS ECU 50, braking ECU 60, driving control ECU 70, etc. (collectively referred to as "actuator ECUs") based on instructions from the driving assistance ECU 80, automatic driving ECU 90, etc. For example, the management ECU 100 issues commands to the driving control ECU 70 regarding acceleration, to the EPS ECU 50 regarding steering, and to the driving control ECU 70 and braking ECU 60 regarding deceleration.

[0039] When the management ECU 100 receives commands from multiple driver assistance ECUs 80, it performs a process called "mediation" based on predetermined rules to determine which command to use to control the vehicle. Based on the mediation result, the management ECU 100 issues commands to the actuator ECU. Driving operations manually performed by the driver (such as steering wheel, brake pedal, and accelerator pedal operations) can be acquired by the management ECU 100 for mediation, or they can be acquired by the actuator ECU, allowing the actuator ECU to mediate between the driver's manual driving operations and the commands from the management ECU 100.

[0040] Storage unit 110 stores vehicle-related driving history. One aspect of the driving history is the history of past vehicle driving, specifically information about the driving power generated by the power source (internal combustion engine 21 and electric motor 31) at various points in time during the driving period. The driving power consists of the driving power of the internal combustion engine 21, the driving power of the electric motor 31, and the power absorbed by the electric motor 31. Another aspect of the driving history is information about the vehicle's speed (vehicle speed) at various points in time during past vehicle driving. For example, this driving history can be generated by periodically storing driving power and vehicle speed derived and obtained based on various sensors installed on the vehicle, etc., while the vehicle's power system (not shown) is turned on, in storage unit 110. For example, storage unit 110 may be part of a car navigation system (not shown) installed in the vehicle.

[0041] The communication unit 120 can perform wireless communication with a server outside the vehicle and other vehicles (not shown), and can receive driving history other than that of the driver, obtained based on the driving results of other vehicles.

[0042] The driving control device 10 is an electronic control unit (ECU) that controls the driving of the vehicle. The driving control device 10 includes an acquisition unit 11, an estimation unit 12, a setting unit 13, a control unit 14, and a derivation unit 15.

[0043] Acquisition unit 11 acquires information about the vehicle's destination, the driving history from the departure point to the destination, and the target charge level of battery 41 upon arrival at the destination (first acquisition unit, second acquisition unit, and third acquisition unit). Estimation unit 12 estimates the expected amount of generated energy, which can be generated in the vehicle, based on the information acquired by acquisition unit 11. Setting unit 13 sets the driving range using electric motor 31 and the driving range using internal combustion engine 21, based on the expected amount of generated energy estimated by estimation unit 12 and the target charge level. Control unit 14 controls the vehicle's driving based on the ranges set by setting unit 13. Derivation unit 15 derives the deviation between the driving power based on the driving history and the actual driving power.

[0044] Each of the aforementioned ECUs typically consists of a computer with memory, a processor, and interfaces. For example, the processor in each ECU reads and executes programs stored in non-transitory memory to perform its respective function. These ECUs are interconnected via communication lines and can work together by communicating with each other appropriately.

[0045] The configuration of the devices installed on the vehicle and the configuration of the driving control device 10 described above are examples, and can be added, replaced, changed, or omitted as appropriate. The functions of each device can be integrated into a single device or appropriately distributed across multiple devices.

[0046] For example, the driving control device 10 can be set as an independent ECU, or it can be set as part of the management ECU 100, driving control ECU 70, etc., or the functions of the driving control device 10 can be distributed in the management ECU 100, driving control ECU 70, etc.

[0047] Furthermore, for example, the driving control unit 10, the driving control ECU 70, the driving assistance ECU 80, the automatic driving ECU 90, and the management ECU 100 can be configured as a single ECU. Additionally, for example, the automatic driving ECU 90 does not necessarily need to be located in the vehicle.

[0048] Control and processing

[0049] The following will refer to further details. Figure 2A , Figure 2B , Figure 3A , Figure 3B and Figure 4 This section will explain in detail examples of the control and processing performed by the driving control device 10 according to this embodiment.

[0050] Figure 2A and Figure 2B This is a flowchart illustrating an example of driving control performed by the driving control device 10. Figure 2A processing and Figure 2B The processing is connected by the connectors V, W, X, and Y. For example, when the driver or others turn on the vehicle's power system and begin the trip, the driving control begins and continues to execute until the vehicle's power system is turned off and the trip ends.

[0051] Step S201

[0052] Control unit 14 determines whether the current time is the initial set time when the control of the driving mode based on the driving scenario has not yet started. If the current time is the initial set time (S201: Yes), the process proceeds to step S202, and if the current time is not the initial set time (S201: No), the process proceeds to step S213.

[0053] Step S202

[0054] The acquisition unit 11 acquires the destination point. For example, the destination point is given by latitude / longitude information. The destination point is the end point of the vehicle's journey or any intermediate point set along the route to that end point. The acquisition unit 11 can acquire the destination point through manual input by the vehicle's driver or other personnel, or through automatic input via the vehicle's onboard navigation system, remote control from a management center outside the vehicle, or other means. As a method of automatically acquiring the destination point, it can be acquired based on the current location, date, time, day of the week, etc., before the journey begins, or it can be acquired based on the vehicle's direction of travel, etc., after the journey begins. Once the destination point is acquired, the process proceeds to step S203.

[0055] Step S203

[0056] The acquisition unit 11 acquires the driving power curve. The driving power curve is a time series of power information indicating the changes in driving power generated by the power source (internal combustion engine 21 and electric motor 31) at various points in time during the journey from the vehicle's starting point (current position) to its destination. Figure 5 This is a graph showing an example of a driving power curve. Figure 5 In the diagram, the horizontal axis represents the elapsed time since the start of the journey, and the vertical axis represents the driving power. Based on information stored, for example, in storage unit 110 (i.e., past driving history along the same route from the starting point to the destination), a driving power curve acquired by acquisition unit 11 is generated (or extracted).

[0057] The following describes a simple example of the generation process. For instance, when the route from the starting point to the destination is a commuter route traveled along the same route at approximately the same time of day, multiple past driving histories stored for that commuter route are expected to have approximately the same pattern of variation in the driving power generated at the power source. In this case, a driving power curve can be generated based on any one of the multiple past driving histories. Furthermore, when attributes such as the day of the week or time of day when the vehicle was driven are provided in the driving history, a driving power curve can be generated based on the driving history with the highest number of attributes matching the current driving. When a navigation system installed in the vehicle creates a driving route from the starting point to the destination, a driving power curve can be generated based on driving history that is highly similar to that driving route.

[0058] For example, when multiple driving histories exist as candidates for a driving power curve, any one of them can be used as the driving power curve, or the driving power curve can be the average of multiple driving histories. If the driving history is vehicle information (e.g., vehicle speed) rather than a time series of power information indicating changes in the driving power generated by the power source during driving, the driving power curve can be generated based on the vehicle information. The method used to generate the driving power curve is not limited, and the above methods can be appropriately combined. Once the driving power curve is obtained, the process proceeds to step S204.

[0059] Step S204

[0060] Unit 11 acquires the speed curve. The speed curve is a time series of information indicating the expected speed of a vehicle at various points in time during its journey from its starting point (current position) to its destination. Figure 7 This is a graph showing an example of a velocity curve. In Figure 7 In the diagram, the horizontal axis represents the elapsed time since the start of the journey, and the vertical axis represents the vehicle's speed.

[0061] Based on information stored, for example, in storage unit 110, namely past driving history along the same route from the departure point to the destination, a speed curve acquired by acquisition unit 11 is generated (or extracted). In a simple example, if the driver's (vehicle's) only driving pattern is commuting along the same route at the same time of day on a weekday, the pattern of speed changes over time in the driving history is expected to be roughly the same. In this case, acquisition unit 11 can create a speed curve based on one of the past driving histories. Furthermore, storage unit 110 can categorize and store driving histories using corresponding attributes such as day of the week and time of day, and acquisition unit 11 can create a speed curve based on the driving history with the highest number of matches to the current driving day of the week, time of day, and other attributes. Once the speed curve is acquired, the process proceeds to step S205.

[0062] Step S205

[0063] Estimation unit 12 estimates the regenerative energy E_est as the electrical energy obtained through regenerative braking of motor 31 during the vehicle's journey from the starting point to the destination. The estimation of regenerative energy E_est is performed based on the driving power curve. Specifically, the time period in the driving power curve where the driving power is negative (less than zero) is the expected time period for recovering regenerative energy (the recovery time period), and the time integral value of the driving power during this recovery time period (i.e., ...) is calculated. Figure 6 The shaded area in the diagram is used as the estimated regenerative energy E_est. When estimating the regenerative energy E_est, variable factors such as increased vehicle weight due to truck loading and inclement weather can be considered, and the estimate can be corrected. Once the regenerative energy E_est is estimated, the process proceeds to step S206.

[0064] It is conceivable that, due to the storage capacity limitation of storage unit 110, the driving power curve stored in storage unit 110 as the aforementioned past driving history may be approximate data rather than actual data. In this case, in order to improve the accuracy of the estimated regenerative energy E_est, the cumulative negative value of driving power can be stored separately from the driving power curve as driving history.

[0065] Step S206

[0066] Estimation unit 12 estimates the generated energy E_gen as electrical energy obtained through efficient power generation during high-speed vehicle travel from the starting point to the destination. The estimation of generated energy E_gen is performed based on a speed curve. Specifically, the high-speed travel period when the vehicle speed is above a predetermined speed (e.g., 100 km / h) on the speed curve is the period during which the internal combustion engine 21 is expected to be highly efficient (power generation period). During this power generation period (i.e., Figure 8The electrical force that can be generated during the shaded time period (in the diagram) is calculated as the estimated generated energy E_gen. When estimating the generated energy E_gen, variable factors such as increased vehicle weight due to truck loading or inclement weather can be considered, and the estimate can be corrected. Once the generated energy E_gen is estimated, the process proceeds to step S207.

[0067] Step S207

[0068] The setting unit 13 initializes the required power generation energy E_req by setting it to zero "0". The required power generation energy E_req is a variable indicating how much electrical energy (electric force) should be obtained through forced power generation when the vehicle is traveling at high speed, and it is determined in the process of generating the driving scenario described below. Once the required power generation energy E_req is initialized to zero, the process proceeds to step S208.

[0069] Step S208

[0070] The acquisition unit 11 acquires the target battery charge rate SOC_tgt. The target battery charge rate SOC_tgt is the charge rate (SOC) of the battery 41 as a target when the vehicle reaches its destination, and can be the charge rate of the battery 41 desired by the vehicle's driver, system, etc. The acquisition unit 11 can acquire the target battery charge rate SOC_tgt through manual input by the vehicle's driver, etc., or through automatic input through the vehicle's in-vehicle navigation system, remote control from a management center outside the vehicle, etc.

[0071] For example, if the destination is a residence with charging facilities, battery 41 can be charged after returning to the residence, so the target energy storage rate SOC_tgt can be set below the standard value. If a large amount of electricity is planned to be used at the destination (e.g., at a residence), the target energy storage rate SOC_tgt can be set above the standard value. Once the target energy storage rate SOC_tgt is obtained, the process proceeds to step S209.

[0072] Step S209

[0073] The acquisition unit 11 acquires the initial charge rate SOC_stt. The initial charge rate SOC_stt is the charge rate of battery 41 when attempting to generate a driving scene. If it is determined in step S201 that the time is the initial setting time, the initial charge rate SOC_stt is the charge rate of battery 41 when driving begins to generate the driving scene for the first time. If it is determined in step S201 that the time is not the initial setting time, the initial charge rate SOC_stt is the charge rate of battery 41 at the midpoint (intermediate location) of driving when the driving scene is generated again. The acquisition unit 11 can acquire the initial charge rate SOC_stt of battery 41 from the battery ECU 40, etc. Once the initial charge rate SOC_stt is acquired, the process proceeds to step S210.

[0074] Step S210

[0075] The setting unit 13 performs the process of generating a driving scenario (driving scenario generation process). The driving scenario is information with a threshold set according to a time series. This threshold is used to divide the route from the current location to the destination into sections where the vehicle uses only the electric motor 31 (hereinafter referred to as the "first section") and sections where the vehicle uses at least the internal combustion engine 21 (hereinafter referred to as the "second section"). The driving scenario generation process will be described below. Once the driving scenario is generated, the process proceeds to step S211.

[0076] Step S211

[0077] Control unit 14 reads the driving scenario generated by the driving scenario generation process. Once the driving scenario is read, the process proceeds to step S212.

[0078] Step S212

[0079] Control unit 14 controls the vehicle's driving mode based on driving scenarios. More specifically, control unit 14 defines a first interval where the driving power is equal to or less than a threshold of the driving scenario, and a second interval where the driving power exceeds the threshold of the driving scenario. In the first interval, control unit 14 selects "electric motor mode" (driving only the electric motor 31) as the driving mode and notifies driving control ECU 70. In response to this notification, driving control ECU 70 causes electric motor ECU 30 to control the driving of electric motor 31. In the second interval, control unit 14, for example, selects "internal combustion engine mode" (driving only the internal combustion engine 21) as the driving mode and notifies driving control ECU 70. In response to this notification, driving control ECU 70 causes internal combustion engine ECU 20 to control the driving of internal combustion engine 21.

[0080] In electric motor mode, regenerative braking is performed by electric motor 31 to recover the vehicle's kinetic energy as electricity. When the driver depresses the brake pedal significantly or the driver assistance ECU 80 issues a high-priority rapid deceleration command to avoid a collision, requiring a certain degree of deceleration, the management ECU 100 and braking ECU 60 execute control to generate braking force through the braking device 61 in order to produce sufficient braking force.

[0081] The above embodiment describes an example where the driving mode in the second interval of the driving scenario is set to internal combustion engine mode, in which only the internal combustion engine 21 is driven for driving. However, since the charge rate of battery 41 is controlled to be almost constant during hybrid driving, instead of internal combustion engine mode, a "hybrid mode" that drives at least the internal combustion engine 21 for driving can be selected as the driving mode for the second interval.

[0082] Step S213

[0083] The derivation unit 15 derives the absolute difference E_d(t) of the power integral value from the starting point (t=0) to the current point (t=T). The absolute difference E_d(t) of the power integral value is the absolute value of the difference between the integral value ΣP_present(t) of the magnitude of the driving power obtained by the actual driving of the vehicle and the integral value ΣP_past(t) of the magnitude of the driving power calculated based on the driving power curve, as shown in the following equation [1]. The absolute difference E_d(t) of the power integral value is derived, for example, at a fixed period after the vehicle leaves the starting point. Once the absolute difference E_d(t) of the power integral value is derived, the process proceeds to step S214. E_d(t)=|ΣP_past(t)–ΣP_present(t)|...[1]

[0084] Step S214

[0085] Control unit 14 determines whether the absolute difference E_d(t) of the power integral values ​​derived by derivation unit 15 exceeds a standard value C. This determination is made to reconsider whether the driving scenario needs to be modified. Therefore, the standard value C is set to an appropriate predetermined value that allows for determinations that the driving scenario needs to be regenerated due to, for example, a significant deviation of the driving power based on the driving scenario generated at the departure point from the driving power curve set based on past driving history. When the absolute difference E_d(t) of the power integral values ​​exceeds the standard value C (E_d(t)>C) (S214: Yes), the process proceeds to step S209 to regenerate the driving scenario. On the other hand, when the absolute difference E_d(t) of the power integral values ​​does not exceed the standard value C (E_d(t)≤C) (S214: No), the process proceeds to step S212 to continue driving mode control based on the current driving scenario.

[0086] Step S215

[0087] The control unit 14 determines whether the battery 41's charge rate has reached an upper limit. This upper limit may be, for example, the charge rate at which the battery 41 is allowed to be overcharged. When the battery 41's charge rate has reached the upper limit (S215: Yes), the process proceeds to step S220. On the other hand, when the battery 41's charge rate has not yet reached the upper limit (S215: No), the process proceeds to step S216.

[0088] Step S216

[0089] Control unit 14 determines whether the vehicle is in a power generation zone and whether the power generation request flag XF is set to "1". This determination is made to determine whether the vehicle's condition meets the conditions for forced power generation. A power generation zone is an area where the vehicle can travel at a high speed (e.g., 100 km / h or higher) that allows for efficient use of the internal combustion engine 21 and efficient power generation in internal combustion engine mode. The power generation request flag XF is a flag indicating whether it is necessary to intentionally (forcefully) increase the amount of power generation between the departure point and the destination point, and is set to "1" or "0" as needed in the following process of generating driving scenarios. When the vehicle is in a power generation zone and the power generation request flag XF = 1 (S216: Yes), the process proceeds to step S217. On the other hand, when the vehicle is not in a power generation zone or the power generation request flag XF ≠ 1 (S216: No), the process proceeds to step S218.

[0090] Step S217

[0091] Control unit 14 uses electric motor 31 or other generator (not shown) to generate electricity in order to obtain the required power generation energy E_req determined in the process of generating the driving scenario described below. Once power generation is performed to obtain the required power generation energy E_req, the process proceeds to step S220.

[0092] Step S218

[0093] Control unit 14 determines whether the vehicle is traveling within a power generation suppression zone. A power generation suppression zone is an area after which a large amount of electrical energy is expected to be recovered. Examples of power generation suppression zones include a predetermined section on a highway before an exit interchange where renewable energy can be expected to be generated due to deceleration. When the vehicle is traveling within a power generation suppression zone (S218: Yes), the process proceeds to step S219. Conversely, when the vehicle is not traveling within a power generation suppression zone (S218: No), the process proceeds to step S220.

[0094] Step S219

[0095] Control unit 14 performs power generation without considering regeneration (power generation) after the vehicle has traveled through the power generation suppression zone. Typically, in the power generation suppression zone, the battery 41's charge rate is pre-reduced by suppressing power generation while the vehicle is traveling in that zone, allowing for efficient recovery of the electrical energy that can be expected to be obtained later. In this embodiment, power generation is performed without suppressing the normally suppressed power generation while traveling in the power generation suppression zone. This allows for efficient recovery of the electrical energy that can be expected to be obtained after traveling in the power generation suppression zone, as well as the generation of highly efficient electrical energy from the power generation during travel in the power generation suppression zone. Once power generation without considering regeneration after traveling in the power generation suppression zone has been performed, the process proceeds to step S220.

[0096] Step S220

[0097] Control unit 14 determines whether the vehicle has reached its destination. If the vehicle has reached its destination (S220: Yes), the process proceeds to step S201 to generate a driving scenario for the next destination. On the other hand, if the vehicle has not yet reached its destination (S220: No), the process proceeds to step S213 to reconsider whether the current driving scenario needs to be modified.

[0098] Reference Figure 3A and Figure 3B , will explain Figure 2A The driving scene generation process shown in step S210. Figure 3A and Figure 3B This is a flowchart illustrating an example of driving scenario generation processing performed by the driving control device 10. Figure 3A processing and Figure 3B The processing is connected by the connectors M and N.

[0099] Step S301

[0100] The setting unit 13 initializes the power generation request flag XF by setting it to "0". Once the power generation request flag XF is set to "0", the process proceeds to step S302.

[0101] Step S302

[0102] The setting unit 13 derives the target energy consumption E_tgt. The target energy consumption E_tgt is the electrical energy consumed during vehicle operation in order to achieve the target energy storage rate SOC_tgt when the vehicle reaches the destination. Based on the estimated regeneration energy E_est, the estimated generation energy E_gen, the required generation energy E_req, the initial energy storage rate SOC_stt, and the full charge capacity C_f of the battery 41, the target energy consumption E_tgt is derived through the following equation [2]. Once the target energy consumption E_tgt is derived, the process proceeds to step S303.

[0103] E_tgt=E_est+E_gen+E_req+(SOC_stt–SOC_tgt)×C_f...[2]

[0104] Step S303

[0105] The setting unit 13 applies a threshold P_swt to the driving power curve to estimate the expected change in the battery 41's charge rate SOC_clc from the current location to when the vehicle reaches its destination. The threshold P_swt is a value representing the driving power at the moment of switching between a first interval where only the electric motor 31 is used for vehicle driving, as described above, and a second interval where at least the internal combustion engine 21 is used for vehicle driving, and can be a value between zero and the maximum power the vehicle can output. For the threshold P_swt, the initial value for the first interval is preset to the low driving power region where the efficiency of the internal combustion engine 21 decreases, and this initial value is appropriately modified according to the processing content. The current location is the vehicle's departure location in the driving scenario generation process executed within the initially set time. Once the change in the battery 41's charge rate SOC_clc is estimated, the processing proceeds to step S304.

[0106] Figure 9 and Figure 10 An example is shown showing the change in the battery's charge rate SOC_clc based on the driving power estimate. Figure 9 This illustrates an example of the change in the battery 41's charge rate SOC_clc when there is no target charge rate SOC_tgt at the destination. Figure 10 An example is shown of the change in the battery 41's charge capacity SOC_clc when a target charge capacity SOC_tgt is present at the destination.

[0107] like Figure 9 and Figure 10 As shown, in the first interval of the driving power curve where the driving power is equal to or greater than zero and equal to or less than the threshold (the time period without shaded lines in the figure), electricity is consumed by the power operation control of the motor 31, causing the battery 41's SOC_clc to decrease. On the other hand, in the first interval where the driving power is less than zero (the time period with shaded lines in the figure), the motor 31 performs regenerative braking, causing electricity to be charged and the battery 41's SOC_clc to increase. In the second interval where the driving power exceeds the threshold in the driving power curve (the time period with shaded lines in the figure), in principle, the motor 31 does not consume electricity, thus maintaining the battery 41's SOC_clc. However, during the period of high-speed driving, the battery 41's SOC_clc increases due to charging through forced power generation.

[0108] Step S304

[0109] The setting unit 13 determines whether there is an intermediate point in the estimated change of the battery 41's charge rate SOC_clc from the current location to the destination point where the charge rate SOC_clc reaches the upper or lower limit of the battery 41. The upper limit of the battery 41 is, for example, the charge rate when the battery 41 is overcharged, and the lower limit of the battery 41 is, for example, the charge rate when the battery 41 is over-discharged. When there is an intermediate point where the charge rate SOC_clc reaches the upper or lower limit of the allowable value (S304: Yes), the process proceeds to step S305. When there is no intermediate point where the charge rate SOC_clc reaches the upper or lower limit of the allowable value (S304: No), the process proceeds to step S306.

[0110] Step S305

[0111] Setting unit 13 determines the current threshold P_swt as the regular threshold to be applied from the undetermined location to the intermediate location. When the current intermediate location is the first time the battery capacity SOC_clc reaches the upper or lower allowable limit of battery 41, the undetermined location in this step is the current location; and when the current intermediate location is the second or more times the battery capacity SOC_clc reaches the upper or lower allowable limit of battery 41, the undetermined location is the previous intermediate location. The number of intermediate locations is unlimited. Once the threshold from the undetermined location to the intermediate location is determined, the process proceeds to step S306.

[0112] Step S306

[0113] Based on the estimated charge rate SOC_clc of the battery 41, the setting unit 13 calculates an estimate of the electric motor driving energy E_mg consumed by the electric motor 31 from the current location until the vehicle reaches its destination. The electric motor driving energy E_mg is calculated based on the integral value of the driving power in the first interval where the driving power is equal to or greater than zero in the driving power curve with the current threshold P_swt applied. When a threshold determined in step S305 exists, the current threshold P_swt and the determined threshold are applied to each relevant time period to calculate the electric motor driving energy E_mg. Once the electric motor driving energy E_mg is calculated, the process proceeds to step S307.

[0114] Step S307

[0115] Setting unit 13 determines whether the motor driving energy E_mg is equal to the target energy consumption E_tgt (E_mg = E_tgt). This determination is made to determine whether the target energy consumption E_tgt is not being consumed excessively or insufficiently under the current threshold P_swt. When the motor driving energy E_mg is equal to the target energy consumption E_tgt (S307: Yes), the process proceeds to step S309. On the other hand, when the motor driving energy E_mg is not equal to the target energy consumption E_tgt (S307: No), the process proceeds to step S308.

[0116] Step S308

[0117] Setting unit 13 performs a process to modify the current threshold P_swt (threshold modification process). This threshold modification process will be described later. Once the threshold P_swt is modified, the process proceeds to step S303.

[0118] Step S309

[0119] The setting unit 13 determines whether the current threshold P_swt exceeds the predetermined driving power value C_p. The value C_p indicates the driving power required to reduce the efficiency of the internal combustion engine 21, and the current threshold P_swt, which is equal to or lower than this value, indicates that the power generation needs to be increased. When the threshold P_swt exceeds the value C_p (S309: Yes), the process proceeds to step S312. On the other hand, when the threshold P_swt does not exceed the value C_p (S309: No), the process proceeds to step S310.

[0120] Step S310

[0121] The setting unit 13 sets the power generation request flag XF to "1". When the power generation request flag XF is set to "1", the process proceeds to step S311.

[0122] Step S311

[0123] Setting unit 13 increases the required power generation energy E_req. More specifically, setting unit 13 adds a very small amount of energy ΔE to the previously required power generation energy E_req, to ​​increase the required power generation energy E_req (E_req←E_req+ΔE). The very small amount of energy ΔE can be set to any value based on the speed and resolution required by the process. Once the required power generation energy E_req has been increased, the process proceeds to step S302.

[0124] Step S312

[0125] Setting unit 13 determines the current threshold P_swt as the regular threshold to be applied from the undetermined location of the threshold to the destination. When the battery charge SOC_clc changes but never reaches the upper or lower allowable limit of battery 41, the undetermined location of the threshold in this step is the current location. When the battery charge SOC_clc reaches the upper or lower allowable limit of battery 41 at least once, the undetermined location of the threshold in this step is the intermediate location where the upper or lower allowable limit was last reached. Once the threshold from the undetermined location to the destination is determined, the process proceeds to step S313.

[0126] Step S313

[0127] The setting unit 13 generates data that is sequentially connected to one or more thresholds determined in steps S305 and S312, and stores the generated data as a driving scenario to be applied from the current location until the vehicle reaches its destination. Once the driving scenario is stored, the driving scenario generation process is complete.

[0128] Figure 4 It shows Figure 3A The threshold modification process shown in step S308. Figure 4 This is a flowchart of an example of threshold modification processing performed by the driving control device 10.

[0129] Step S401

[0130] Setting unit 13 determines whether the motor driving energy E_mg is greater than the target energy consumption E_tgt (E_mg>E_tgt). This determination is made to decide how to modify the threshold P_swt. When the motor driving energy E_mg is greater than the target energy consumption E_tgt (S401: Yes), the process proceeds to step S402. On the other hand, when the motor driving energy E_mg is not greater than the target energy consumption E_tgt (S401: No), the process proceeds to step S403.

[0131] Step S402

[0132] Setting unit 13 reduces the threshold P_swt because electrical energy is sufficient even when all estimated regenerative energy E_est is consumed. Specifically, setting unit 13 changes the current threshold P_swt to a value that reduces a small amount of power Δp (P_swt ← P_swt – ΔP). The small amount of power ΔP can be set to any value based on the performance of the power source, the difference between the motor's operating energy E_mg and the target energy consumption E_tgt. As a method for reducing the threshold P_swt in step S402, in addition to the method described above of reducing the threshold P_swt by a fixed value of power Δp, a method can also be used that sets the intermediate value between the current threshold P_swt and the lower limit threshold P_swt_min, which is the minimum threshold that can be set, as the modified threshold (P_swt ← (P_swt + P_swt_min) / 2) (binary search method). Once the threshold P_swt is reduced, the threshold modification process is complete.

[0133] Step S403

[0134] Setting unit 13 increases the threshold P_swt because not all of the estimated regenerative energy E_est can be consumed. Specifically, setting unit 13 changes the current threshold P_swt to a value that increases by a small amount of power Δp (P_swt ← P_swt + ΔP). The small amount of power ΔP can be set to any value based on the performance of the power source, the difference between the motor's operating energy E_mg and the target energy consumption E_tgt. Furthermore, as a method for increasing the threshold P_swt in step S403, in addition to the method described above of increasing the threshold P_swt by a fixed amount of power ΔP, a method can also be used that sets the intermediate value between the current threshold P_swt and the upper limit threshold P_swt_max, which is the maximum threshold that can be set, as the modified threshold (P_swt ← (P_swt + P_swt_max) / 2) (binary search method). Once the threshold P_swt is increased, the threshold modification process is completed.

[0135] Note that when generating a driving scenario, based on the acquired driving power curve, speed curve, and initial energy storage rate SOC_stt, there is a possibility that the estimated regenerative energy E_est cannot be completely consumed and the target energy storage rate SOC_tgt upon reaching the destination cannot be achieved. In this case, either the complete consumption of the estimated regenerative energy E_est or the achievement of the target energy storage rate SOC_tgt upon reaching the destination can be prioritized when generating the driving scenario. The fact that the energy storage rate SOC_clc has not reached the upper or lower allowable limit can be given priority when generating the driving scenario.

[0136] Figure 11 and Figure 12 An example of a method for determining the threshold P_swt for a driving scenario is shown. Figure 11 This is a diagram illustrating an example of an intermediate point where the energy storage rate SOC_clc reaches the allowable upper limit of battery 41. Figure 12 This is a diagram illustrating an example of an intermediate point where the energy storage rate SOC_clc reaches the allowable lower limit value of battery 41.

[0137] exist Figure 11 In the process, the threshold (a) used as the initial value of the threshold P_swt is first applied to the driving power curve to estimate the change (a) of the battery's charge rate SOC_clc. However, using this change (a), the target charge rate SOC_tgt cannot be obtained upon reaching the destination, so the threshold P_swt is modified and reduced to the threshold (b1). Even using this threshold (b1), the target charge rate SOC_tgt cannot be obtained, but there is an intermediate point P1 where the charge rate SOC_clc reaches the allowable upper limit, so the threshold from the starting point to the intermediate point P1 is determined as the threshold (b1). Finally, from the intermediate point P1 to the destination, the threshold (c1) that causes the change (c1) is determined, and the target charge rate SOC_tgt can be obtained upon reaching the destination. Using this method, a driving scenario was generated in which driving mode switching control is performed based on a threshold (b1) for the time from the starting point to the intermediate point P1, and driving mode switching control is performed based on a threshold (c1) for the time from the intermediate point P1 to the destination.

[0138] exist Figure 12 In the process, the threshold (a) used as the initial value of the threshold P_swt is first applied to the driving power curve to estimate the change (a) of the battery 41's charge rate SOC_clc. However, using this change (a), the target charge rate SOC_tgt cannot be obtained upon reaching the destination, so the threshold P_swt is modified and increased to the threshold (b2). Even using this threshold (b), the target charge rate SOC_tgt cannot be obtained, but there is an intermediate point P2 where the charge rate SOC_clc reaches the allowable lower limit, so the threshold from the starting point to the intermediate point P2 is determined as the threshold (b2). Finally, from the intermediate point P2 to the destination, the threshold (c2) that causes the change (c2) is determined, and the target charge rate SOC_tgt can be obtained upon reaching the destination. Using this method, a driving scenario was generated in which driving mode switching control is performed based on a threshold (b2) for the time from the starting point to the intermediate point P2, and driving mode switching control is performed based on a threshold (c2) for the time from the intermediate point P2 to the destination.

[0139] Using the above processing, it is possible to estimate the change in power consumption for each journey from the starting point to the destination, as well as the amount of regenerated energy recovered (E_est) and efficiently generated energy (E_gen). Based on these factors, a driving scenario can be generated that improves fuel efficiency while achieving efficient consumption of the target energy (E_tgt), including the complete consumption of the estimated regenerated energy (E_est), and obtaining the target energy storage rate (SOC_tgt) when the vehicle reaches the destination. When the deviation between the estimated value and the value obtained through actual driving increases, the driving scenario is checked to ensure optimal driving control is always achieved.

[0140] Operation and Effect

[0141] As described above, the vehicle driving control device 10 according to this embodiment quantitatively estimates the amount of recovered regenerated energy E_est in the early stages based on past driving history using a driving power curve, which is a time series of the expected change in driving power generated by the power source during vehicle travel from the starting point to the destination. Furthermore, a speed curve is used to estimate the generated energy E_gen obtained through efficient power generation during high-speed driving, which is a time series of the expected vehicle speed during vehicle travel from the starting point to the destination. Therefore, these estimation results can be used to perform appropriate vehicle driving control taking into account the target energy storage rate of the battery 41.

[0142] The driving control unit 10 performs control to enable the internal combustion engine 21 to be driven in the most efficient region possible by using the electric motor 31 for driving under conditions of low engine efficiency. When regenerative energy can be estimated to be large, such as on a downhill slope, the driving control unit 10 performs control to pre-reduce the charge rate of the battery 41 to eliminate or reduce unrecovered energy. Furthermore, the driving control unit 10 performs control to actively generate electricity during high-speed driving with good engine efficiency, thereby increasing the time the vehicle can travel using the electric motor 31, which improves fuel efficiency / electricity efficiency. Moreover, since the driving control unit 10 controls the driving mode by setting a first and a second range, ensuring that the charge rate of the battery 41 does not exceed the upper limit and does not fall below the lower limit, the degradation process of the battery 41 can be suppressed. These controls can appropriately improve fuel efficiency while achieving efficient consumption of the target energy E_tgt (including complete consumption of the estimated regenerative energy E_est) and the acquisition of the target charge rate SOC_tgt when the vehicle reaches its destination.

[0143] Although embodiments of the present disclosure have been described above, the present disclosure can be implemented by appropriate modifications. The present disclosure can be understood not only as a driving control device, but also as a driving control method executed by a driving control device including a processor and a memory, a driving control program, a computer-readable non-transitory storage medium storing a driving control program, a vehicle equipped with a driving control device, etc.

[0144] This disclosure applies to driving control devices installed on vehicles, etc.

Claims

1. A driving control device installed on a vehicle equipped with an electric motor and an internal combustion engine as power sources, the driving control device comprising: The first acquisition unit acquires the destination location of the vehicle; The second acquisition unit acquires the past driving history from the departure point to the destination point; The third acquisition unit acquires the target energy storage rate, which is the energy storage rate of the battery installed in the vehicle as the target at the time when the vehicle arrives at the destination. An estimation unit that estimates the expected amount of generated energy based on the driving history, the generated energy being the energy that can be generated in the vehicle until the vehicle reaches the destination; The setting unit sets a first interval and a second interval based on the expected amount of generated energy and the target energy storage rate, wherein the first interval is an interval in which only the electric motor is driven for driving, and the second interval is an interval in which at least the internal combustion engine is driven for driving. The derivation unit derives the difference between the time integral value of the power generated in the power source based on the driving history to the current location and the time integral value of the power generated in the power source based on the actual driving to the current location, wherein when the absolute value of the difference derived by the derivation unit is equal to or greater than a predetermined standard value, the setting unit resets the first interval and the second interval from the current location to the destination. as well as A control unit that controls the movement of the vehicle based on the first and second intervals.

2. The driving control device according to claim 1, wherein, The driving history includes information indicating a time series of changes in the power generated in the power source when driving from the departure point to the destination point in the past, and information indicating a time series of changes in the vehicle's speed when driving from the departure point to the destination point.

3. The driving control device according to claim 2, wherein, The estimation unit considers the time periods in the driving history during which the power generated in the power source is negative as recovery time periods in which energy can be recovered, and estimates the time integral value of the magnitude of the power generated in the power source during the recovery time period as at least a portion of the expected amount of the generated energy.

4. The driving control device according to claim 2, wherein, The estimation unit considers the time periods during which the vehicle travels at a predetermined speed or above in the driving history as the power generation time periods during which the internal combustion engine can be used to perform efficient power generation, and estimates the energy generated during the power generation time periods as at least a portion of the expected amount of the generated energy.

5. The driving control device according to claim 1, wherein, The setting unit sets the first interval and the second interval such that at the moment when the vehicle arrives at the destination, all of the expected amount of generated energy is consumed.

6. The driving control device according to any one of claims 1 to 5, wherein, The setting unit sets the first interval and the second interval so that the battery's energy storage rate does not exceed the upper limit or is not lower than the lower limit.

7. A driving control method executed by a driving control device installed on a vehicle equipped with an electric motor and an internal combustion engine as power sources, the driving control method comprising: The steps to obtain the destination location of the vehicle; The steps to obtain the past driving history from the departure point to the destination point; The step of obtaining the target energy storage rate is the energy storage rate of the battery installed in the vehicle, which is the target, at the time when the vehicle arrives at the destination. The step of estimating the expected amount of generated energy based on the driving history, wherein the generated energy is the energy that can be generated in the vehicle until the vehicle reaches the destination; The steps of setting a first interval and a second interval based on the expected amount of generated energy and the target energy storage rate, wherein the first interval is the interval in which only the electric motor is driven for driving, and the second interval is the interval in which at least the internal combustion engine is driven for driving; The step of deriving the difference between the time integral value of the power generated in the power source based on the driving history to the current location and the time integral value of the power generated in the power source based on the actual driving to the current location, wherein when the absolute value of the derived difference is equal to or greater than a predetermined standard value, the first interval and the second interval from the current location to the destination are reset. as well as The steps for controlling the vehicle's movement based on the first interval and the second interval.

8. A storage medium storing a driving control program executed by a computer of a driving control device installed in a vehicle equipped with an electric motor and an internal combustion engine as power sources, the driving control program comprising: The steps to obtain the destination location of the vehicle; The steps to obtain the past driving history from the departure point to the destination point; The step of obtaining the target energy storage rate is the energy storage rate of the battery installed in the vehicle, which is the target, at the time when the vehicle arrives at the destination. The step of estimating the expected amount of generated energy based on the driving history, wherein the generated energy is the energy that can be generated in the vehicle until the vehicle reaches the destination; The steps of setting a first interval and a second interval based on the expected amount of generated energy and the target energy storage rate, wherein the first interval is the interval in which only the electric motor is driven for driving, and the second interval is the interval in which at least the internal combustion engine is driven for driving; The step of deriving the difference between the time integral value of the power generated in the power source based on the driving history to the current location and the time integral value of the power generated in the power source based on the actual driving to the current location, wherein when the absolute value of the derived difference is equal to or greater than a predetermined standard value, the first interval and the second interval from the current location to the destination are reset. as well as The steps for controlling the vehicle's movement based on the first interval and the second interval.

Images