Vehicle control device

Abstract

To provide a vehicle control device capable of appropriately exerting performance of a vehicle while protecting a power transmission mechanism.SOLUTION: A vehicle control device includes a driving power source and a power transmission mechanism transmitting power of the driving power source between the driving power source and driving wheels, can selectively set an automatic operation travel travelling on a prescribed travel route without performing a drive operation by a driver, and is provided with a controller controlling the drive power source. The controller is configured so as to perform output limit control controlling output of the drive power source so that an input torque becomes smaller than a first limit torque when it is predicted that the input torque to the power transmission mechanism becomes larger than the predetermined first limit torque (step S2). When the automatic drive travel is set (YES in step S1), the output limit control is executed on the basis of a second limit torque calculated based on a vehicle travel condition predicted from the travel route (step S3).SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a vehicle control device that can selectively set automatic driving. [Background technology]

[0002] Patent Document 1 discloses a control device for a hybrid vehicle that aims to suppress deterioration of durability of parts due to over-revving of the engine during power-on downshifting of the automatic transmission. The hybrid vehicle of Patent Document 1 includes a power source for driving including an engine and a second rotating machine, a battery capable of exchanging electric power with the second rotating machine, and an automatic transmission capable of setting a plurality of gear stages between the power source and the drive wheels. In the control device of Patent Document 1, when the input rotation speed of the automatic transmission increases faster than the target, the input torque to the automatic transmission is reduced by reducing the torque of the second rotating machine below the command value of the second rotating machine, and the input rotation speed to the automatic transmission is controlled to be the target value. On the other hand, when the torque of the second rotating machine cannot be sufficiently reduced due to restrictions on charging the battery, power corresponding to the torque that could not be reduced by increasing the engine rotation speed is consumed. At this time, in the device of Patent Document 1, when it is predicted that the engine rotation speed will exceed a predetermined rotation speed, the engine power (engine torque) is limited in advance to be equal to or less than a predetermined power (predetermined torque). Patent Document 1 claims that such a configuration makes it possible to execute a power-on downshift without over-revving the engine. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-099946 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the device of Patent Document 1, the predetermined power that is the reference for limiting the engine power is the upper limit of the engine power allowed during power-on downshift of the automatic transmission. Such an upper limit of the engine power is set so as to protect the gears, clutches, etc. that constitute the automatic transmission. In particular, in manual driving, it is difficult to predict what kind of driving operation will be performed by the driver. Therefore, in order to reliably prevent the input torque to the hardware such as the gears and clutches from becoming excessive and reducing the durability, the upper limit or limit value of the torque input to the hardware is set relatively low. In other words, the limit value of the input torque to the hardware is set assuming a driving operation that always has the worst effect on the hardware. Therefore, even if the driver performs a sudden driving operation, the gears and clutches can be reliably protected. On the other hand, even if a torque larger than the limit value is actually input to the hardware, the hardware can be protected, but the output of the power source may be limited. In other words, because the upper limit value of the input torque to the hardware is set in this way, the output of the power source may be excessively suppressed, and the acceleration and speed intended by the driver may not be obtained.

[0005] Furthermore, in a vehicle capable of autonomous driving, the vehicle travels along a predetermined route during autonomous driving, so the possibility of a sudden increase in the required driving force as described above is low compared to manual driving. Even if such a sudden increase in the required driving force does occur, it is possible to control the magnitude of the output of the power source by taking into account hardware constraints using a control device or the like. However, as described above, since the output of the power source is set, the result is that the output of the power source is excessively restricted. This could lead to inconveniences such as not being able to fully utilize the performance of the vehicle.

[0006] The present invention has been made in light of the above technical problems, and aims to provide a vehicle control device that is capable of properly demonstrating the performance of the vehicle while protecting the power transmission mechanism. [Means for solving the problem]

[0007] In order to achieve the above-mentioned object, the present invention provides a control device for a vehicle that has a driving force source and a power transmission mechanism that transmits the power of the driving force source between the driving force source and driving wheels, and is capable of selectively setting automatic driving travel along a predetermined driving route without driving operation by the driver, and is provided with a controller that controls the driving force source, and the controller is configured to perform output limiting control that controls the output of the driving force source so that the input torque is smaller than the first limit torque when it is predicted that the input torque to the power transmission mechanism will exceed a predetermined first limit torque, and when the automatic driving travel is set, the controller performs the output limiting control based on a second limit torque calculated based on the driving state of the vehicle predicted from the driving route. Effect of the Invention

[0008] According to the vehicle control device of the present invention, when it is predicted that the input torque to the power transmission mechanism will exceed a predetermined first limit torque, output limit control is executed to control the output of the driving force source so that the torque does not exceed the first limit torque. Therefore, it is possible to suppress a decrease in durability of the gears, clutches, and the like that constitute the power transmission mechanism. In addition, when an automatic driving mode is set in which the vehicle is driven based on a predetermined driving route, the output limit control is executed based on a second limit torque calculated based on the vehicle's driving state predicted from the driving route. In other words, when the automatic driving mode is set, the limit value of the input torque to the power transmission mechanism can be changed according to the driving route and the vehicle state. For example, the limit value of the input torque can be relaxed or the limit value of the torque can be temporarily eliminated. Therefore, since the limit of the output to the driving force source can be relaxed, the performance of the vehicle can be effectively utilized, and thus the fuel efficiency of the vehicle and the responsiveness of the vehicle can be improved. [Brief description of the drawings]

[0009] [Figure 1] 1 is a diagram illustrating an example of a vehicle equipped with a control device according to an embodiment of the present invention. [Diagram 2] FIG. 4 is an explanatory diagram for explaining an example of data input to a controller. [Diagram 3] 4 is a flowchart showing an example of control executed by a control device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The present invention will be described below based on the embodiments shown in the drawings. Note that the embodiments described below are merely examples of the present invention and are not intended to limit the present invention.

[0011] FIG. 1 shows an example of the configuration of a vehicle Ve equipped with a control device according to an embodiment of the present invention. The vehicle Ve shown in FIG. 1 is a vehicle capable of manual driving, in which the vehicle is driven by a driver's driving operation, and automatic driving, in which the vehicle is driven without the driver's driving operation. In automatic driving, the driving force, braking force, steering amount, etc. are controlled without the driver's driving operation by recognizing the driving environment and monitoring the surrounding situation based on peripheral information acquired from the outside of the vehicle. For example, the vehicle Ve traces data related to the estimated or measured position of the vehicle Ve, and calculates control amounts such as the driving force, braking force, steering amount, etc., to control the vehicle Ve so that the vehicle Ve can run along a predetermined target trajectory based on the data related to the position of the vehicle Ve and map data, thereby executing automatic driving.

[0012] The vehicle Ve is a hybrid vehicle having an engine (Eng) 1 and a motor generator (MG) 2 as a driving force source that outputs a driving force for traveling, and a power transmission mechanism for transmitting the torque of the driving force source to the driving wheels. As shown in FIG. 1, the vehicle Ve has a K0 clutch 4, a lock-up clutch 5, a torque converter 6, and a transmission (Gear Train) 7 as a power transmission mechanism 3, and also has a case 8 that houses these mechanisms. The vehicle Ve also has an electric oil pump (EOP) 9, a mechanical oil pump 10, and a valve body 11 (V / B) for supplying oil to the engine 1, the motor, and the power transmission mechanism 3 as needed. The vehicle Ve also has a detection unit 12 and a controller (ECU) 13. The motor 2, the K0 clutch 4, and the torque converter 6 may be collectively referred to as a front module.

[0013] The engine 1 can be configured in the same manner as a conventional gasoline engine or diesel engine. The engine 1 is equipped with an output torque variable mechanism, such as a variable valve system or an electronically controlled throttle. The engine 1 is configured to output a driving torque by burning a mixture of fuel and air supplied thereto, and to output a braking torque according to friction torque, pumping loss, and the like by stopping the combustion of the mixture. The engine 1 is configured such that the fuel injection amount, ignition timing, throttle opening, and the like are controlled according to the operating state and running state, and the output torque is appropriately increased or decreased. The engine 1 is cranked by a starter motor, a clutch start, a motor 2, or the like.

[0014] The output shaft 1a of the engine 1 is provided with a K0 clutch 4, which is a friction-type engagement mechanism and is engaged or released by hydraulic pressure. The K0 clutch 4 is a clutch provided between the output shaft 1a of the engine 1 and the connecting shaft 2a of the motor 2 in the power transmission path between the engine 1 and the drive wheels. When the K0 clutch 4 is engaged, the engine 1 is in a state in which it can transmit torque to the power transmission mechanism 3. Conversely, when the K0 clutch 4 is released, the engine 1 is separated from the power transmission mechanism 3 and is in a state in which it cannot transmit torque. For example, when the motor 2 outputs torque in this state, the vehicle Ve can be driven only by the torque of the motor 2, which is called EV driving. In addition, the K0 clutch 4 is configured to be slip-controlled so that the engine speed can be increased (cranked) when the engine 1 is started. The K0 clutch 4 may be either a wet type or a dry type.

[0015] The motor 2 generator (hereinafter referred to as the motor 2) 2 is, for example, a three-phase AC synchronous motor in which a rotor 2c with a permanent magnet is disposed inside a stator 2b having magnetic poles. The motor 2 is electrically connected to a battery (not shown) and outputs a drive torque for running the vehicle Ve according to the power supplied from the battery. In addition, the motor 2 is configured to be capable of generating power to charge the battery when it is rotated.

[0016] A torque converter 6 is connected to the connecting shaft 2a of the motor 2 on the side opposite to the K0 clutch 4. This torque converter 6 is configured similarly to a conventional torque converter. That is, the torque converter 6 is configured by a pump impeller 6a connected to the connecting shaft 2a of the motor 2, a turbine runner 6b arranged opposite to the pump impeller 6a, and a stator 6c arranged between the pump impeller 6a and the turbine runner 6b and connected to the case 8.

[0017] The torque converter 6 is also provided with a lock-up clutch 5 for transmitting the input torque to the transmission 7 without amplifying it through the torque converter 6. The lock-up clutch 5 is configured to be able to engage the connecting shaft 2a of the motor 2 with the turbine runner 6b. This lock-up clutch 5 can be configured in the same manner as a conventional lock-up clutch 5. In other words, the lock-up clutch 5 is configured to be able to appropriately change the rotation speed difference between the connecting shaft 2a of the motor 2 (or the output shaft 1a of the engine 1) and the turbine runner 6b through slip control.

[0018] Further, a mechanical oil pump 10 is connected to the pump impeller 6a of the torque converter 6. The mechanical oil pump 10 is driven by the engine 1 or the motor 2 to discharge oil used in the power transmission mechanism 3.

[0019] The output shaft 6d of the torque converter 6 is connected to the transmission 7. The transmission 7 is a device capable of appropriately changing the gear ratio, and changes the gear ratio or the gear stage by combining the meshing of gears (not shown) and the engagement and disengagement of a clutch 7a or the like. The gears and the clutch 7a can be selectively engaged by controlling the hydraulic pressure, or when the clutch 7a is a friction clutch, the transmission torque capacity can be changed continuously. The torque output from the transmission 7 is transmitted to the drive wheels from the output shaft of the transmission 7 via a propeller shaft, a differential gear, a drive shaft (none of which are shown), and the like. The transmission 7 may be a stepless or stepped automatic transmission, or may be a manual transmission.

[0020] The electric oil pump 9 is driven by torque output from a pump motor (not shown) to discharge oil. The oil pump draws up oil that has accumulated in an oil pan (not shown) disposed, for example, below the case 8, and supplies the oil to the power transmission mechanism 3 and the like.

[0021] The valve body 11 is a hydraulic control device, and is supplied with oil discharged from the mechanical oil pump 10 or the electric oil pump 9. The valve body 11 adjusts pressure based on the oil pressure discharged from the electric oil pump 9 or the mechanical oil pump 10, and supplies engagement pressure to the above-mentioned K0 clutch 4, lock-up clutch 5, transmission 7, etc. In addition, oil for cooling and lubrication of the engine 1, motor 2, power transmission mechanism 3, etc. is supplied from the valve body 11.

[0022] The detection unit 12 is a device or apparatus for acquiring various data and information required for controlling the vehicle Ve, and includes, for example, a power supply unit, a microcomputer, a sensor, an input / output interface, etc. The detection unit 12 is electrically connected to the controller 13, and is configured to output, as detection data, electric signals and the like corresponding to detected values ​​or calculated values ​​of the above-mentioned various sensors, devices, and the like to the controller 13. Although not shown in the figures, examples of sensors included in the detection unit 12 include an engine rotation speed sensor, a turbine rotation speed sensor, a motor rotation speed sensor, an engine torque sensor, and an accelerator opening sensor.

[0023] The controller 13 is an electronic control device mainly composed of, for example, a microcomputer. Various data detected or calculated by the above-mentioned detection unit 12 are input to the controller 13. The controller 13 performs calculations using the input various data and pre-stored data, calculation formulas, etc. Then, the controller 13 is configured to output the calculation result as a control command signal and control the vehicle Ve as described above. The controller 13 is also configured to obtain driving route information for performing automatic driving. The driving route information includes position information of the vehicle Ve, map information, traffic information including congestion information, etc. The controller 13 controls the output of the engine 1 and the motor 2, the gear ratio of the transmission 7, etc. based on the information.

[0024] The detection unit 12, the controller 13, and the actuators and sensors for driving the vehicle Ve are electrically connected to each other by, for example, a CAN or a wire harness, and output an electric signal corresponding to the acquired detected value or calculated value as detection data to the controller 13. Although an example in which one controller 13 is provided is shown in Fig. 1, a plurality of controllers 13 may be provided for each device or equipment to be controlled, or for each control content.

[0025] 2 shows an example of data input from the detection unit 12 to the controller 13. Specifically, as data of the vehicle Ve, data such as vehicle speed, accelerator opening, rotation speed of the output shaft 1a of the engine 1 (engine rotation speed), rotation speed of the output shaft of the motor 2 (motor rotation speed), output torque of the engine 1, output torque of the motor 2, rotation speed of the turbine runner 6b (i.e., input rotation speed of the transmission 7), output rotation speed of the transmission 7, and gear ratio (shift range) of the transmission 7 are input to the controller 13. These values ​​are detected by the detection unit 12 or calculated based on the detected values. Based on the input data, the controller 13 controls the output of the engine 1 and the motor 2, engagement or release of the gears and clutch 7a constituting the transmission 7, the amount of oil and hydraulic pressure supplied from the valve body 11 to parts requiring oil, and the like.

[0026] Various controls are executed by the controller 13 configured in this manner. One example is the start control of the engine 1, which cranks the stopped engine 1 to start it. For the start control of the engine 1, a TDC start control that uses a compression stroke stopped cylinder of the engine 1 to increase the engine speed by self-rotation of the engine 1, or a PUSH start control that engages the K0 clutch 4 to increase the engine speed by the motor 2, as is conventionally known, may be used. In this manner, the controller 13 is configured to perform start control or stop control of the vehicle Ve by controlling the engine 1, the motor 2, and the K0 clutch 4 in a coordinated manner. The controller 13 may also be configured to perform a coordinated manner with the lock-up clutch 5 and the transmission 7.

[0027] In addition to these controls, the controls by the controller 13 include lock-up control for controlling the hydraulic pressure to slip the lock-up clutch 5, slip control for controlling the engagement pressure to slip the friction clutch constituting the transmission 7 to engage or disengage, shift judgment control for executing a shift in the transmission 7 based on a pre-stored shift map, throttle control for controlling the throttle valve of the engine 1, start control for controlling the driving force source and the power transmission mechanism 3 when the vehicle Ve starts, K0 clutch control for controlling the engagement state and transmission torque capacity of the K0 clutch 4, motor control for controlling the output of the motor 2, battery control for controlling the battery based on the remaining charge and temperature, etc. The controller 13 executes these controls as necessary or required to appropriately control the running of the vehicle Ve.

[0028] The control executed by the controller 13 also includes an output limit control that controls the output of the driving force source to limit the torque input to the transmission 7 so as to suppress a decrease in durability of hardware such as the gears and the clutch 7a in the transmission 7 while the vehicle Ve is traveling. In manual driving where the vehicle Ve travels by the driver's driving operation, it is difficult to predict the driving route of the vehicle Ve, the road surface condition, or the driver's operation. Therefore, a limit value or upper limit value of the torque input to the transmission 7 is set assuming a case where the hardest load is applied. For example, assuming a case where the accelerator is operated most suddenly from the current driving state of the vehicle Ve, a first limit torque that is a limit value or upper limit value of the torque that can reliably protect the components constituting the transmission 7 even in such a case is determined in advance. In the output limit control, the output torque of the driving force source is controlled based on the first limit torque. Therefore, even if the driver performs a sudden accelerator operation, a decrease in durability in the transmission 7 and the power transmission mechanism 3 can be suppressed.

[0029] On the other hand, such a limitation of the output torque of the driving force source may result in failure to obtain the acceleration or vehicle speed intended by the driver. In addition, when the vehicle Ve travels by automatic driving, a travel route is determined in advance, and the vehicle Ve basically travels along that route. Therefore, the behavior of the vehicle Ve while traveling can be predicted based on the planned travel route, and the sudden increase in the required acceleration as described above is unlikely to occur. Even if such a situation does occur, it is possible to control the output of the driving force source while recognizing the hardware constraints. Therefore, when the input torque to the transmission 7 is limited during automatic driving, as in the case of manual driving, the output of the driving force source may be excessively limited, and the performance of the vehicle Ve may not be effectively utilized.

[0030] Therefore, the control device in the embodiment of the present invention is configured to change the limit value of the input torque to the transmission 7 according to the driving mode of the vehicle Ve, thereby making it possible to drive the vehicle Ve while making the most of its performance. Fig. 3 shows a flowchart for explaining an example of such control.

[0031] In the flowchart shown in Fig. 3, first, in step S1, it is determined whether or not autonomous driving has been selected. Autonomous driving is started, for example, by pressing a dedicated switch provided in the vehicle Ve, or by remote control by an external operator. If autonomous driving has been selected in the vehicle Ve and the determination is YES in step S1, the process proceeds to step S2.

[0032] In step S2, a second limit torque is set as a limit value of the torque input to the transmission 7. When the process proceeds to step S2, the vehicle Ve is in autonomous driving mode, and as described above, the driving route and the like are set in advance, and the behavior of the vehicle Ve can be predicted based on information about the driving route. Therefore, requests that deviate from hardware constraints are unlikely to be made of the engine 1 and the motor 2. Therefore, in step S2, a second limit torque that is a relaxation of the first limit torque of the transmission 7 that is set in advance is set.

[0033] Specifically, in the case of autonomous driving, a driving pattern is set based on a set planned driving route. That is, based on information on the planned driving route, for example, information on the curvature of intersections and roads, the presence or absence of traffic jams and road surface inclination, the presence of obstacles and other vehicles, and the like, on the route on which the vehicle Ve is scheduled to travel, driving control of the vehicle Ve is executed. Therefore, during autonomous driving, the timing of acceleration and braking, or the gear ratio and engine speed of the transmission 7, can be predicted based on the current position of the vehicle Ve and the planned driving route. The second limit torque is set by being appropriately calculated based on the predicted driving state of the vehicle Ve, taking into consideration the amount of change in the engine speed, the output speed, or the vehicle speed. That is, the second limit torque is set to a value that can adequately bring out the performance of the driving force source and the like and protect the transmission 7 according to the driving state of the vehicle Ve. Alternatively, it is set to a torque that essentially releases the restriction on the input torque to the transmission 7 temporarily. In this way, the second limit torque, which is reduced from the first limit torque, is set for the input torque to the transmission 7, and this flow chart is temporarily terminated.

[0034] On the other hand, if the result of step S1 is NO because manual driving has been selected in the vehicle Ve, the process proceeds to step S3. In step S3, the first limit torque, which is the limit value of the input torque to the transmission 7, is maintained. The first limit torque is an input torque that can protect the gears and clutch 7a of the transmission 7 even when a driving operation that places the greatest load on the power transmission mechanism 3 and the like is performed. When the process proceeds to step S3, the vehicle Ve is traveling by manual driving by the driver, so it is difficult to predict the travel route and what driving operation will be performed on the vehicle Ve. Therefore, the first limit torque is set for the input torque of the transmission, and this flowchart is temporarily terminated.

[0035] According to the control device in the embodiment of the present invention, in order to protect hardware such as the gears and clutch 7a of the transmission 7, a first limit torque, which is a limit value of the torque input to the transmission 7, is set. During the traveling of the vehicle Ve, output limit control is executed to control the output of the engine 1 and the motor 2 so as not to exceed the first limit torque. Therefore, it is possible to suppress a decrease in durability of the gears and clutch 7a constituting the transmission 7. In addition, when automatic driving traveling is set in the vehicle Ve, the limit value of the input torque to the transmission 7 is set to a second limit torque calculated based on the traveling state of the vehicle Ve predicted from the planned traveling route. Then, the above-mentioned output limit control is executed based on the second limit torque. Therefore, for example, the limit value of the input torque to the transmission 7 can be relaxed, or the limit value of the input torque can be temporarily set to be substantially eliminated. Therefore, since the limit of the output to the driving force source can be relaxed, the performance of the vehicle Ve can be brought out, and thus the fuel efficiency of the vehicle Ve and the responsiveness of the vehicle Ve can be improved.

[0036] Although the embodiment of the present invention has been described above, the present invention is not limited to the above-mentioned examples, and may be modified as appropriate within the scope of achieving the object of the present invention. For example, when the vehicle Ve is driven in a specific environment, such as a circuit, the input torque to the transmission 7 may be limited to the second limit torque even in manual driving. [Explanation of symbols]

[0037] 1 Engine 2 Motors 3 Power transmission mechanism 4 K0 clutch 5 Lock-up clutch 6. Torque converter 7. Transmission 8 Cases 9. Electric oil pump 10 Mechanical oil pump 11 Valve body 12 Detection section 13 Controller Vehicle

Claims

[Claim 1] A driving force source; a power transmission mechanism that transmits power of the driving power source between the driving power source and a driving wheel, A control device for a vehicle that can selectively set automatic driving driving in which the vehicle travels along a predetermined driving route without a driver performing a driving operation, A controller for controlling the driving force source, The controller: when it is predicted that an input torque to the power transmission mechanism will exceed a predetermined first limit torque, an output limiting control is performed to control an output of the driving force source so that the input torque becomes smaller than the first limit torque, When the automatic driving is set, the output limit control is executed based on a second limit torque calculated based on a driving state of the vehicle predicted from the driving route. A vehicle control device comprising:

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