Control device for a vehicle

Abstract

The present application provides a control device of a vehicle, which appropriately maintains follow-up running while suppressing a temperature rise of working oil caused by a decrease in cooling performance of a heat exchanger. Oil temperature suppression control is executed during execution of follow-up running in which automatic running is performed at a prescribed inter-vehicle distance from a preceding vehicle, in which the control state of a lock-up clutch is changed so as to suppress a temperature rise of working oil that circulates within a fluid-type power transmission device and that is used in switching of the control state of the lock-up clutch, and thus a heat generation amount from the fluid-type power transmission device including the lock-up clutch can be reduced without changing an actual inter-vehicle distance with respect to the prescribed inter-vehicle distance in follow-up running. Therefore, the temperature rise of the working oil caused by the decrease in the cooling performance of the heat exchanger can be suppressed while appropriately maintaining the follow-up running.

Description

TECHNICAL FIELD

[0001] The present application relates to a control device of a vehicle that controls follow-up running. BACKGROUND

[0002] A control device of a vehicle that automatically runs at a prescribed inter-vehicle distance from a preceding vehicle is well known. For example, a vehicle running control device described in Patent Literature 1 is such a control device. In this Patent Literature 1, it is disclosed that when the inflow air flow rate into the vehicle is less than the necessary air flow rate, the inflow air flow rate is increased by causing at least a portion of the portion that introduces air into the vehicle to separate from a separation region in which the air flow rate is reduced from behind the preceding vehicle.

[0003] PRIOR ART DOCUMENTS

[0004] PATENT LITERATURE

[0005] Patent Literature 1: Japanese Patent Application Publication No. 2012-201133 SUMMARY

[0006] PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] In follow-up running, the preceding vehicle becomes a windshield, and the air flow rate that collides with the following vehicle is reduced, and thus the running resistance is reduced. On the other hand, the cooling performance of an air-to-air heat exchanger is reduced. The reduction in cooling performance can, for example, cause an increase in the temperature of an object that is cooled by the heat exchanger. The object is, for example, working oil that circulates in a fluid-type transmission that is provided in a power transmission path between a power source and a drive wheel and has a lock-up clutch, and that is used for switching the control state of the lock-up clutch. The increase in the temperature of the working oil can, for example, cause deterioration of the working oil. As disclosed in Patent Literature 1, if the reduction in the inflow air flow rate is suppressed by changing the state of follow-up running, such as by lengthening the inter-vehicle distance from the prescribed inter-vehicle distance, the reduction in the cooling performance of the heat exchanger is suppressed, but the running resistance is increased.

[0008] The present application is made in view of the above situation, and aims to provide a control device of a vehicle that can suppress an increase in the temperature of working oil caused by a reduction in the cooling performance of a heat exchanger while appropriately maintaining follow-up running.

[0009] MEANS FOR SOLVING THE PROBLEMS

[0010] The gist of the first aspect is that (a) a control device of a vehicle that has a power source and a fluid-type transmission device provided in a power transmission path between the power source and a drive wheel and having a lock-up clutch, (b) the control device of the vehicle includes a follow-up travel control section that controls follow-up travel in which the vehicle is automatically traveled at a prescribed inter-vehicle distance from a preceding vehicle, and (c) a lock-up clutch control section that controls the lock-up clutch to any one of a release state, a slip state, and an engagement state, (d) the lock-up clutch control section executes oil temperature suppression control in which the control state of the lock-up clutch is changed so as to suppress a temperature rise of working oil that circulates in the fluid-type transmission device and is used in switching of the control state of the lock-up clutch during execution of the follow-up travel.

[0011] Further, in the control device of the vehicle according to the first aspect, in the second aspect, the oil temperature suppression control is control that switches the lock-up clutch that is controlled to the release state or the slip state based on a predetermined relationship to the engagement state.

[0012] Further, in the control device of the vehicle according to the first aspect, in the third aspect, the oil temperature suppression control is control that switches the lock-up clutch that is controlled to the release state based on a predetermined relationship to the engagement state and switches the lock-up clutch that is controlled to the slip state based on the relationship to the release state.

[0013] Further, in the control device of the vehicle according to any one of the first aspect to the third aspect, in the fourth aspect, the lower the temperature rise of the working oil, the lower the prescribed oil temperature that the lock-up clutch control section sets, and the oil temperature suppression control is executed to reduce the amount of heat generated from the fluid-type transmission device in a case where it is determined that the temperature of the working oil is the prescribed oil temperature or higher.

[0014] Further, in the control device of the vehicle according to the fourth aspect, in the fifth aspect, the temperature rise of the working oil varies according to an environment of a travel route that is expected in future travel, and the lock-up clutch control section sets the prescribed oil temperature based on environment information of the travel route.

[0015] Further, in the vehicle control device according to the fifth aspect, in a sixth aspect, the lock-up clutch control section calculates a vehicle load expected in future travel based on environmental information of the travel route, and sets the prescribed oil temperature to a lower value as the vehicle load is greater.

[0016] Further, in the vehicle control device according to the fourth aspect, in a seventh aspect, the ease of temperature increase of the working oil varies according to an inter-vehicle distance with respect to the preceding vehicle, and the lock-up clutch control section sets the prescribed oil temperature to a lower value as the inter-vehicle distance is shorter.

[0017] Further, in the vehicle control device according to the fourth aspect, in an eighth aspect, the ease of temperature increase of the working oil varies according to a projected area of the preceding vehicle, and the lock-up clutch control section sets the prescribed oil temperature to a lower value as the projected area when viewed from behind the preceding vehicle is greater.

[0018] Further, in the vehicle control device according to the fourth aspect, in a ninth aspect, the ease of temperature increase of the working oil varies according to a vehicle dimension in a direction orthogonal to a travel direction of the preceding vehicle, i.e., a width of the preceding vehicle, and the lock-up clutch control section sets the prescribed oil temperature to a lower value as the width of the preceding vehicle is greater.

[0019] Further, in the vehicle control device according to the fourth aspect, in a tenth aspect, the lock-up clutch control section sets a control end threshold value used in the end determination of the oil temperature suppression control to a value lower than the prescribed oil temperature used in the start determination of the oil temperature suppression control, and ends the oil temperature suppression control when it is determined that the temperature of the working oil is equal to or lower than the control end threshold value during execution of the oil temperature suppression control.

[0020] Further, in the vehicle control device according to any one of the first through third aspects, in an eleventh aspect, the follow-up travel control section suspends the follow-up travel when it is determined that execution of the follow-up travel becomes difficult due to a change in travel performance caused by the oil temperature suppression control.

[0021] Further, in the vehicle control device according to the eleventh aspect, in a twelfth aspect, the follow-up travel control section suspends the follow-up travel after there is a driver's instruction or permission when it is determined that execution of the follow-up travel becomes difficult.

[0022] Further, in the vehicle control device according to any one of the first to third aspects, in a thirteenth aspect, in a case where a failure of any one of the fluid-type transmission including the lock-up clutch and a device associated with control of the fluid-type transmission is detected, the lock-up clutch control section prohibits the oil temperature suppression control.

[0023] Further, in the vehicle control device according to any one of the first to third aspects, in a fourteenth aspect, in a case where the follow-up travel is ended during execution of the oil temperature suppression control, the lock-up clutch control section ends the oil temperature suppression control.

[0024] Effects of Invention

[0025] According to the first aspect, the oil temperature suppression control is executed during execution of the follow-up travel in which the vehicle is automatically traveling at a prescribed inter-vehicle distance with respect to the preceding vehicle, in which the control state of the lock-up clutch is changed so as to suppress a temperature rise of working oil that circulates within the fluid-type transmission and that is used in switching of the control state of the lock-up clutch, and thus, without changing the actual inter-vehicle distance with respect to the prescribed inter-vehicle distance in the follow-up travel, it is possible to reduce the heat generation amount from the fluid-type transmission including the lock-up clutch. Therefore, it is possible to appropriately maintain the follow-up travel while suppressing a temperature rise of the working oil due to a decrease in cooling performance of the heat exchanger.

[0026] Further, according to the second aspect, since the oil temperature suppression control is control that switches the lock-up clutch that is controlled to the released state or the slipping state based on a predetermined relationship to the engaged state, it is possible to appropriately reduce the heat generation amount from the fluid-type transmission including the lock-up clutch.

[0027] Further, according to the third aspect, since the oil temperature suppression control is control that switches the lock-up clutch that is controlled to the released state based on a predetermined relationship to the engaged state and switches the lock-up clutch that is controlled to the slipping state based on a predetermined relationship to the released state, it is possible to appropriately reduce the heat generation amount from the fluid-type transmission including the lock-up clutch.

[0028] Further, according to the fourth aspect, the lower the temperature of the working oil is likely to rise, the lower the prescribed oil temperature is set, and in a case where it is determined that the temperature of the working oil is the prescribed oil temperature or higher, the oil temperature suppression control is executed to reduce the heat generation amount from the fluid-type transmission, and thus, when the working oil is in a state in which the temperature is likely to rise, it is possible to execute the oil temperature suppression control in advance, and it is possible to suppress a temperature rise of the working oil.

[0029] In addition, according to the fifth aspect, the easiness of the temperature increase of the working oil varies depending on the environment of the travel route expected in future travel, and the prescribed oil temperature is set based on the environment information of the travel route, so the oil temperature suppression control can be executed in advance when the temperature of the working oil easily increases due to the environment of the travel route.

[0030] In addition, according to the sixth aspect, the vehicle load expected in future travel is calculated based on the environment information of the travel route, and the prescribed oil temperature is set to a lower value as the vehicle load is greater, so the oil temperature suppression control can be executed in advance when the temperature of the working oil easily increases due to the greater vehicle load.

[0031] In addition, according to the seventh aspect, the easiness of the temperature increase of the working oil varies depending on the inter-vehicle distance with respect to the preceding vehicle, and the prescribed oil temperature is set to a lower value as the inter-vehicle distance is shorter, so the oil temperature suppression control can be executed in advance when the temperature of the working oil easily increases due to the shorter inter-vehicle distance.

[0032] In addition, according to the eighth aspect, the easiness of the temperature increase of the working oil varies depending on the projected area of the preceding vehicle, and the prescribed oil temperature is set to a lower value as the projected area when viewed from behind the preceding vehicle is greater, so the oil temperature suppression control can be executed in advance when the temperature of the working oil easily increases due to the greater projected area.

[0033] In addition, according to the ninth aspect, the easiness of the temperature increase of the working oil varies depending on the width of the preceding vehicle, and the prescribed oil temperature is set to a lower value as the width of the preceding vehicle is greater, so the oil temperature suppression control can be executed in advance when the temperature of the working oil easily increases due to the greater width of the preceding vehicle.

[0034] In addition, according to the tenth aspect, during execution of the oil temperature suppression control, the oil temperature suppression control is ended when it is determined that the temperature of the working oil is below a control end threshold value that is set to a lower value than the prescribed oil temperature used in the start determination of the oil temperature suppression control, so hunting in which the start and end of the oil temperature suppression control are repeated in a short time can be avoided, and the oil temperature suppression control can be ended after the temperature increase of the working oil is sufficiently suppressed.

[0035] In addition, according to the eleventh aspect, the following travel is suspended when it is determined that the execution of the following travel becomes difficult due to a change in travel performance caused by the oil temperature suppression control, so the temperature increase of the working oil caused by the following travel can be avoided.

[0036] In addition, according to the twelfth aspect, when it is determined that execution of the follow-up travel becomes difficult, the follow-up travel is suspended after the presence of an instruction by the driver or permission is obtained, and thus it is possible to appropriately shift from the follow-up travel of the automatic travel to travel based on the operation of the driver.

[0037] In addition, according to the thirteenth aspect, in a case where a failure of any one of the fluid-type transmission including the lock-up clutch and the device associated with the control of the fluid-type transmission is detected, the oil temperature suppression control is prohibited, and thus the oil temperature suppression control is not performed when it is possible that the control state of the lock-up clutch cannot be appropriately changed.

[0038] In addition, according to the fourteenth aspect, during execution of the oil temperature suppression control, when the follow-up travel is ended, the oil temperature suppression control is ended, and thus the oil temperature suppression control is not performed when the follow-up travel is not performed, and it is possible to simplify the control of the entire vehicle. In addition, when the follow-up travel is not performed, the control state of the lock-up clutch is not limited with respect to the temperature increase of the working oil. BRIEF DESCRIPTION OF DRAWINGS

[0039] Figure 1 is a diagram that explains the outline structure of a vehicle to which the present application is applied, and is a diagram that explains the main part of the control function and the control system for various controls in the vehicle.

[0040] Figure 2 is a diagram that explains the outline structure of a cooling system that cools oil.

[0041] Figure 3 is a diagram that shows an example of a lock-up region line map used in the control of the lock-up clutch.

[0042] Figure 4 is a diagram that shows an example of a preset relationship for setting the oil temperature threshold value based on the inter-vehicle distance.

[0043] Figure 5 is a diagram that shows an example of a preset relationship for setting the oil temperature threshold value based on the projected area of the preceding vehicle.

[0044] Figure 6 is a diagram that shows an example of a preset relationship for setting the oil temperature threshold value based on the preceding vehicle width.

[0045] Figure 7 is a diagram that shows an example of a preset relationship for setting the oil temperature threshold value based on the expected load.

[0046] Figure 8is a flowchart illustrating a main part of the control work of the electronic control device, and is a flowchart illustrating the control work for appropriately maintaining follow-up running while suppressing an increase in the oil temperature caused by a decrease in the cooling performance of the heat exchanger.

[0047] Figure 9 is a flowchart illustrating a main part of the control work of the electronic control device, and is a flowchart illustrating the control work for appropriately maintaining follow-up running while suppressing an increase in the oil temperature caused by a decrease in the cooling performance of the heat exchanger, and is an embodiment different from that of Figure 8 .

[0048] Figure 10 is an example of a timing chart in a case where the control work illustrated in the flowchart of Figure 9 is executed.

[0049] Figure 11 is a flowchart illustrating a main part of the control work of the electronic control device, and is a flowchart illustrating the control work for appropriately maintaining follow-up running while suppressing an increase in the oil temperature caused by a decrease in the cooling performance of the heat exchanger, and is an embodiment different from that of Figure 8 .

[0050] Figure 12 is a flowchart illustrating a main part of the control work of the electronic control device, and is a flowchart illustrating the control work for appropriately maintaining follow-up running while suppressing an increase in the oil temperature caused by a decrease in the cooling performance of the heat exchanger, and is an embodiment different from that of Figure 8 .

[0051] Figure 13 is a flowchart illustrating a main part of the control work of the electronic control device, and is a flowchart illustrating the control work for appropriately maintaining follow-up running while suppressing an increase in the oil temperature caused by a decrease in the cooling performance of the heat exchanger, and is an embodiment different from that of Figure 8 .

[0052] BRIEF DESCRIPTION OF DRAWINGS

[0053] 10: vehicle

[0054] 12: engine (power source)

[0055] 14: drive wheel

[0056] 20: torque converter (fluid-type power transmission device)

[0057] 36: LU clutch (lock-up clutch)

[0058] 90: electronic control device (control device)

[0059] 96: LU clutch control section (lock-up clutch control section)

[0060] 98: follow-up travel control section

[0061] FLD: oil (working oil)

[0062] MG: rotating machine (power source)

[0063] SP: power source. DETAILED DESCRIPTION

[0064] In the embodiment of the application, the vehicle capable of the follow-up travel is, for example, a vehicle of the engine drive type, an electric automobile, or a hybrid electric vehicle provided with an engine and a rotating machine as a power source, and the like, which has been used conventionally. The engine is, for example, an internal combustion engine such as a gasoline engine or a diesel engine. The rotating machine is, for example, a motor generator capable of being selectively used as a motor and a generator. The motor generator functions as a power source by being used as a motor and is capable of imparting regenerative braking by being used as a generator. The rotating machine can also be, for example, a motor incapable of obtaining the function of a generator.

[0065] In addition, an automatic transmission can be provided in the power transmission path between the fluid type transmission device and the drive wheels. The automatic transmission is, for example, a stepped transmission such as a planetary gear type, a synchronous engagement type parallel double shaft type, or the like, a continuously variable transmission such as a belt type, or the like. The transmission ratio in the automatic transmission is "the rotational speed of the input rotary member / the rotational speed of the output rotary member". The high speed side transmission ratio of the automatic transmission is the side where the transmission ratio becomes smaller, that is, the high vehicle speed side transmission ratio. The low speed side transmission ratio of the automatic transmission is the side where the transmission ratio becomes larger, that is, the low vehicle speed side transmission ratio. For example, the lowest speed side transmission ratio is the lowest vehicle speed side transmission ratio where the transmission ratio becomes the minimum value, and is the maximum transmission ratio where the transmission ratio becomes the maximum value.

[0066] In the case where the automatic transmission is provided in the vehicle, the working oil is a transmission oil (=gearbox oil) used in the automatic transmission. For example, the working oil is an ATF (=Automatic Transmission Fluid) used in a stepped transmission such as a planetary gear type, a CVTF used in a continuously variable transmission such as a belt type, or the like.

[0067] In addition, the follow-up travel can be, for example, a manned travel in which a driver is on board, or an unmanned travel in which the driver is not on board by using an automatic steering system capable of traveling along a pre-set travel route, or the like.

[0068] Further, the control device calculates a drive request amount required for follow-up travel in order to maintain the inter-vehicle distance between the host vehicle and the preceding vehicle as a target inter-vehicle distance set in advance as a prescribed inter-vehicle distance, for example, in follow-up travel, and controls the output of the power source so as to be able to obtain the drive request amount, thereby executing follow-up travel control that follows up with the target inter-vehicle distance. For the output control of the power source in the follow-up travel control, it is desirable to control including negative torque generated by engine braking, regeneration control of the rotary machine, and the like, and it is also possible to perform brake force control via an automatic brake system.

[0069] Further, the vehicle capable of follow-up travel can also be a following vehicle in platooning. The platooning is, for example, travel performed by the platooning participating vehicles that are connected and controlled via wireless communication, including a lead vehicle and following vehicles that are spaced apart at prescribed inter-vehicle distances from the lead vehicle and automatically follow up with the lead vehicle in a column.

[0070] Hereinafter, an embodiment of the present application will be described in detail with reference to the accompanying drawings.

[0071] Embodiment 1

[0072] Figure 1 is a diagram that explains the outline structure of the vehicle 10 to which the present application is applied, and is a diagram that explains the main part of the control function and control system for various controls in the vehicle 10. In Figure 1 In the vehicle 10, the engine 12 and the rotary machine MG that function as a power source SP are provided. Further, the vehicle 10 is provided with the drive wheels 14 and the power transmission device 16 that is provided in the power transmission path between the engine 12 and the drive wheels 14.

[0073] The engine 12 is a known internal combustion engine such as a gasoline engine or a diesel engine. The engine 12 is controlled by controlling the engine control device 50 including a throttle valve actuator, a fuel injection device, an ignition device, and the like, which are equipped in the vehicle 10, by the electronic control device 90 described later, thereby controlling the output torque of the engine 12, that is, the engine torque Te.

[0074] The rotary electric machine MG is a rotary electric machine having a function as a motor that generates mechanical power from electric power and a function as a generator that generates electric power from mechanical power, and is a so-called motor generator. The rotary electric machine MG is connected to a storage battery 54 provided in the vehicle 10 via an inverter 52 provided in the vehicle 10. The storage battery 54 is an electric power storage device that receives and supplies electric power with respect to the rotary electric machine MG. The rotary electric machine MG controls an output torque, that is, an MG torque Tm, by controlling the inverter 52 using an electronic control device 90 described later. For example, in a case where a rotation direction of the rotary electric machine MG is a forward rotation direction that is the same as a rotation direction of the engine 12 at the time of operation of the engine 12, the MG torque Tm is a traction torque in a case where the MG torque Tm is a positive torque on the acceleration side, and is a regenerative torque in a case where the MG torque Tm is a negative torque on the deceleration side. In a case where no particular distinction is made, the electric power has the same meaning as electric energy. In a case where no particular distinction is made, the mechanical power has the same meaning as driving force, torque, and force.

[0075] The power transmission device 16 includes a torque converter 20, an automatic transmission 22, and the like in a non-rotating member, that is, a housing 18, which is mounted to a vehicle body. The torque converter 20 is coupled to the engine 12. The automatic transmission 22 is coupled to the torque converter 20 and is provided in a power transmission path between the torque converter 20 and the drive wheels 14. In addition, the power transmission device 16 includes a propeller shaft 26 coupled to an output rotating member, that is, a transmission output shaft 24, of the automatic transmission 22, a differential gear 28 coupled to the propeller shaft 26, a pair of drive shafts 30 coupled to the differential gear 28, and the like. In addition, the power transmission device 16 includes a rotary electric machine coupling shaft 32 and the like that couples the engine 12 and the torque converter 20.

[0076] The rotary electric machine MG is coupled to the rotary electric machine coupling shaft 32 in the housing 18 so as to be able to transmit power. That is, the rotary electric machine MG is coupled to the power transmission path between the engine 12 and the drive wheels 14 so as to be able to transmit power, and in particular, is coupled to the power transmission path between the engine 12 and the torque converter 20 so as to be able to transmit power. In other words, the rotary electric machine MG is coupled to the torque converter 20 and the automatic transmission 22 so as to be able to transmit power.

[0077] The torque converter 20 has a pump impeller 20a coupled to the rotating machine coupling shaft 32 and a turbine impeller 20b coupled to an input rotating member, i.e., a transmission input shaft 34, of the automatic transmission 22. The pump impeller 20a is an input member of the torque converter 20, and the turbine impeller 20b is an output member of the torque converter 20. The rotating machine coupling shaft 32 is also an input rotating member of the torque converter 20. The transmission input shaft 34 is also an output rotating member of the torque converter 20 formed integrally with a turbine shaft that is rotationally driven by the turbine impeller 20b. The torque converter 20 is a fluid-type power transmission device provided in a power transmission path between the power source SP and the drive wheels 14 and transmits power from the rotating machine coupling shaft 32 to the transmission input shaft 34 via fluid from the power source SP. Fluid circulating within the torque converter 20 is also working oil used in switching of a control state of the LU clutch 36 described later. This working oil is also transmission oil used in a shift operation and the like of the automatic transmission 22. In the present embodiment, this transmission oil is referred to as oil FLD.

[0078] The torque converter 20 has the LU clutch 36 that couples the pump impeller 20a and the turbine impeller 20b, i.e., couples the rotating machine coupling shaft 32 and the transmission input shaft 34. The LU clutch 36 is a direct coupling clutch, i.e., a well-known lock-up clutch, that couples the input and output rotating members of the torque converter 20.

[0079] The LU clutch 36 is, for example, a hydraulic friction engagement device composed of a multiple-plate or single-plate clutch. The LU clutch 36 switches a working state, i.e., a control state, by changing a torque capacity, i.e., an LU torque Tlu, of the LU clutch 36 using a pressurized hydraulic pressure, i.e., an LU hydraulic pressure PRlu, supplied from a hydraulic control circuit 56 provided in the vehicle 10.

[0080] As the control state of the LU clutch 36, there are a state in which the LU clutch 36 is released, i.e., a released state (also referred to as a fully released state), a state in which the LU clutch 36 is engaged with slip, i.e., a slip state, and a state in which the LU clutch 36 is engaged, i.e., an engaged state (also referred to as a fully engaged state). By making the LU clutch 36 into the released state, the torque converter 20 can be made into a torque conversion state in which a torque amplification effect can be obtained. In addition, by making the LU clutch 36 into the engaged state, i.e., lock-up on, the torque converter 20 can be made into a lock-up state in which the pump impeller 20a and the turbine impeller 20b rotate integrally.

[0081] The automatic transmission 22 is, for example, a publicly known planetary gear type automatic transmission provided with the engagement device CB and one or more sets of planetary gear devices not shown. The engagement device CB includes, for example, a plurality of publicly known hydraulic friction engagement devices. The engagement device CB switches the control states of the engaged state, the slipping state, the released state, and the like by changing the respective torque capacities Tcb of the engagement devices CB by using the pressurized hydraulic pressures PRcb supplied from the hydraulic control circuit 56.

[0082] The automatic transmission 22 is a stepped transmission that forms any one of a plurality of shift ranges (also referred to as gear stages) having different gear ratios γ (= AT input rotational speed Ni / AT output rotational speed No) by engagement of any one of the engagement devices CB. The automatic transmission 22 switches the gear stage formed in correspondence with the driver's ( = driver's) accelerator operation, vehicle speed V, and the like by using the electronic control device 90 described later. The AT input rotational speed Ni is the rotational speed of the transmission input shaft 34 and is the input rotational speed of the automatic transmission 22. The AT input rotational speed Ni is the same value as the output rotational speed of the torque converter 20, i.e., the turbine rotational speed Nt. The AT input rotational speed Ni can be expressed by the turbine rotational speed Nt. The AT output rotational speed No is the rotational speed of the transmission output shaft 24 and is the output rotational speed of the automatic transmission 22.

[0083] In the power transmitting device 16, the power output from the power source SP is transmitted to the drive wheels 14 from the rotary mechanical connection shaft 32 via the torque converter 20, the automatic transmission 22, the propeller shaft 26, the differential gear 28, the drive shaft 30, and the like in this order.

[0084] The vehicle 10 is provided with a mechanical oil pump, i.e., MOP 38. The MOP 38 is coupled to the pump impeller 20a and is rotationally driven by the power source SP to discharge the working oil, i.e., oil FLD, used in the power transmitting device 16. The oil FLD discharged from the MOP 38 is supplied to the hydraulic control circuit 56. The hydraulic control circuit 56 supplies the CB hydraulic pressure PRcb, the LU hydraulic pressure PRlu, and the like, each of which is pressurized based on the oil FLD discharged from the MOP 38.

[0085] The vehicle 10 is provided with a wheel brake device 58. The wheel brake device 58 is provided with a master cylinder and a cylinder actuator, which generate brake hydraulic pressure, and the like, which are not shown. Wheels including the drive wheels 14 and a non-illustrated driven wheel are each provided with a wheel brake 59. In addition, if the vehicle 10 is a four-wheel drive vehicle, the driven wheel is a drive wheel. The wheel brake device 58 is a brake device that imparts a wheel brake torque, which is a brake torque generated by the wheel brake 59, to the wheels in accordance with an instruction from an electronic control device 90 described later. The wheel brake device 58 supplies brake hydraulic pressure to non-illustrated wheel cylinders provided to the wheel brakes 59 in accordance with, for example, a depression operation of a brake pedal and the like performed by the driver. In the wheel brake device 58, a master cylinder hydraulic pressure of a size corresponding to a brake operation amount Bra is supplied to the wheel cylinders as brake hydraulic pressure from the master cylinder at normal times. On the other hand, in the wheel brake device 58, for example, at times when an ABS function is operating, at times when side slip suppression control is being performed, at times when automatic vehicle speed control is being performed, at times when automatic driving control is being performed, at times when an automatic brake function is operating, at times when regenerative control is being performed, and the like, brake hydraulic pressure of a size corresponding to a wheel brake torque required in each control is supplied to the wheel cylinders in order to generate the wheel brake torque. The brake operation amount Bra is a signal indicating a size of a depression operation of the brake pedal, which is a size of a depression force of the brake pedal, performed by the driver.

[0086] Figure 2 is a diagram that illustrates an outline configuration of a cooling system 60 that cools the oil FLD mounted on the vehicle 10. In Figure 2 , the cooling system 60 is provided with, for example, a radiator 62, a water pump 64, and a heat exchanger 66. In addition, Figure 2 the solid arrow in indicates a flow of the cooling water CLT, and the broken arrow indicates a flow of the oil FLD.

[0087] The radiator 62 receives the cooling water CLT that flows out from the water jacket of the engine 12, cools the cooling water CLT by heat exchange with outside air, and causes the cooled cooling water CLT to flow out to the water pump 64. The water pump 64 is provided to the engine 12, for example, sucks in the cooling water CLT that flows out from the radiator 62, a bypass passage 68 of the water jacket of the engine 12, and the heat exchanger 66, and supplies the cooling water CLT to the water jacket of the engine 12, causing the cooling water CLT to circulate to each portion.

[0088] The heat exchanger 66 receives the cooling water CLT flowing out from the water jacket of the engine 12, and after circulating the cooling water CLT inside itself, causes it to flow out to the water pump 64. Also, the heat exchanger 66 receives the oil FLD flowing out from the hydraulic control circuit 56, torque converter 20, etc., and after circulating the oil FLD inside itself, causes it to flow out to the hydraulic control circuit 56. Thus, in the heat exchanger 66, heat exchange is performed between the oil FLD and the cooling water CLT. In the heat exchanger 66, for example at the time of cold start (during warm-up), heat is transferred from the cooling water CLT heated by the engine 12 to the oil FLD, and the oil FLD is warmed up in advance. On the other hand, after warm-up, heat is transferred from the oil FLD heated by the torque converter 20, etc. to the cooling water CLT, and the oil FLD is cooled. In this way, the heat exchanger 66 is a heat exchanger for oil that performs heat exchange between the oil FLD and the cooling water CLT, and is, for example, an oil cooler.

[0089] Returning to Figure 1 , the vehicle 10 is also provided with an electronic control device 90 that includes a control device of the vehicle 10. The electronic control device 90 is configured to include, for example, a so-called microcomputer that includes a CPU, a RAM, a ROM, an input / output interface, etc., and the CPU performs various controls of the vehicle 10 by performing signal processing using the temporary storage function of the RAM and in accordance with a program stored in advance in the ROM. The electronic control device 90 is configured to include, as needed, an engine control computer, a motor control computer, a clutch control computer, a transmission control computer, etc.

[0090] Various signals and the like based on detection values of various sensors and the like (for example, an engine speed sensor 70, a turbine speed sensor 71, an output speed sensor 72, an MG speed sensor 73, an accelerator opening degree sensor 74, a throttle opening degree sensor 75, a brake sensor 76, a battery sensor 77, an oil temperature sensor 78, a gear position sensor 79, a vehicle surrounding information sensor 80, a navigation system 81, an automatic cruise setting device 82, and the like) equipped in the vehicle 10 are supplied to the electronic control device 90, respectively (for example, a speed of the engine 12, that is, an engine speed Ne, a turbine speed Nt which is the same value as an AT input speed Ni, an AT output speed No which corresponds to a vehicle speed V, a speed of a rotary machine MG, that is, an MG speed Nm, an accelerator operation amount of a driver, that is, an accelerator opening degree θacc which indicates a magnitude of an acceleration operation of the driver, an opening degree of an electronic throttle, that is, a throttle opening degree θth, a signal which indicates a state in which a brake pedal for operating the wheel brake 59 is operated by the driver, that is, a brake on signal Bon, a brake operation amount Bra, a temperature of the battery 54, that is, a battery temperature THbat, a charge / discharge current of the battery 54, that is, a battery charge / discharge current Ibat, a voltage of the battery 54, that is, a battery voltage Vbat, a temperature of the oil FLD in the hydraulic control circuit 56, that is, an oil temperature THoil, an operation position which indicates a position in which the shift lever is operated (= an operation position) POSop, vehicle surrounding information Iard, navigation information Inavi, automatic cruise setting information Icru, and the like).

[0091] The vehicle surrounding information sensor 80 directly acquires information related to a road on which the vehicle 10 is traveling and information related to an object existing in a periphery of the vehicle, for example, by including at least one of an optical radar, a radar, and a vehicle-mounted camera. The vehicle surrounding information sensor 80 detects an object in front of the vehicle 10, an object on a side of the vehicle 10, an object behind the vehicle 10, and the like, respectively, for example, and outputs object information related to the detected object as the vehicle surrounding information Iard. The object information includes a distance and a direction of the detected object from the vehicle 10. The vehicle surrounding information Iard includes, for example, an inter-vehicle distance Dis with respect to a preceding vehicle which is a vehicle traveling directly in front of the vehicle 10, a projected area Area when viewed from behind the preceding vehicle, a width of the preceding vehicle, that is, a preceding vehicle width Wid, which is a vehicle dimension in a direction orthogonal to a traveling direction of the preceding vehicle, and the like.

[0092] The navigation system 81 is a publicly known navigation system having a display, a speaker, and the like. The navigation system 81 determines a current vehicle position on map data stored in advance, for example, based on position information based on a GPS (Global Positioning System) signal (orbit signal) or the like emitted from a GPS satellite. Upon input of a destination, the navigation system 81 calculates a travel route from a departure point to the destination, and gives an instruction of the travel route or the like to the driver through the display, the speaker, or the like. The navigation information Inavi includes, for example, map information such as road information, facility information, and the like based on map data stored in advance in the navigation system 81. In addition, the navigation information Inavi includes, for example, weather information, traffic information, and the like acquired through communication or the like.

[0093] The automatic cruise setting device 82 is a device that selects automatic cruise travel of constant speed travel and follow-up travel as an automatic travel in which the power source SP is automatically controlled so as to travel at a target travel state set in advance without speed-up or speed-down operation by the driver. That is, the vehicle 10 is capable of automatic cruise travel in which the power source SP is automatically controlled in accordance with the target vehicle speed Vt or the like in addition to manual travel in which the power source SP is controlled in accordance with speed-up or speed-down operation by the driver based on an accelerator pedal or the like. The automatic cruise setting device 82 is a device that sets the target vehicle speed Vt, increases or decreases the target vehicle speed Vt, sets the target inter-vehicle distance Dt at the time of follow-up travel of a preceding vehicle, and the like in addition to selection of automatic cruise travel, and is provided, for example, at a steering wheel or the like, and the target vehicle speed Vt, the target inter-vehicle distance Dt, and the like are input by the driver as automatic cruise setting information Icru.

[0094] Various command signals (for example, an engine control command signal Se for controlling the engine 12, an MG control command signal Sm for controlling the rotary machine MG, a CB hydraulic control command signal Scb for controlling the engagement device CB, an LU hydraulic control command signal Slu for controlling the LU clutch 36, a brake control command signal Sbra for controlling the wheel brake torque, and the like) are output from the electronic control device 90 to each device (for example, the engine control device 50, the inverter 52, the hydraulic control circuit 56, the wheel brake device 58, and the like) provided in the vehicle 10.

[0095] In order to realize various controls in the vehicle 10, the electronic control device 90 functionally includes a power source control section, that is, a power source control 92, a transmission control section, that is, a transmission control 94, an LU clutch control section, that is, an LU clutch control 96, and a follow-up travel control section, that is, a follow-up travel control 98.

[0096] The power source control portion 92 is a hybrid control portion that performs hybrid control such as hybrid drive control for causing the engine 12 and the rotating electric machine MG to operate in coordination. The power source control portion 92 calculates a drive request amount of the vehicle 10 by applying, for example, the accelerator opening degree θacc and the vehicle speed V to a drive request amount map, for example. The drive request amount map is a relationship that is obtained in advance through experiments or design and is stored, that is, a relationship that is set in advance. The drive request amount is a required value of a drive amount that is output from the vehicle 10. The drive amount is, for example, a drive force Fr, a drive torque Tr, or the like in the drive wheels 14, and the drive request amount is, for example, a required drive force Frdem, a required drive torque Trdem, or the like in the drive wheels 14. The power source control portion 92 outputs an engine control command signal Se for controlling the engine 12 and an MG control command signal Sm for controlling the rotating electric machine MG so that a torque of the power source SP required for achieving the required drive torque Trdem can be obtained, for example, taking into account a transmission loss, an auxiliary machine load, a gear ratio γ of the automatic transmission 22, and the like.

[0097] The power transmission device 16 can also include, for example, a clutch for engine disconnection / connection that disconnects power transmission between the engine 12 and the rotating electric machine MG in a power transmission path between the engine 12 and the drive wheels 14. In the case where the clutch for engine disconnection / connection is provided, the power source control portion 92 can perform motor travel, that is, BEV (Battery Electric Vehicle) travel in which only the rotating electric machine MG is used as the power source SP to travel with the clutch for engine disconnection / connection in a released state and the engine 12 in a stopped state. For example, in a case where the required drive torque Trdem can be satisfied by only the output of the rotating electric machine MG, the power source control portion 92 establishes a BEV drive mode as a drive mode. The BEV drive mode is an electric drive mode in which BEV travel (= electric travel) can be performed. On the other hand, in a case where the required drive torque Trdem cannot be satisfied at least without using the output of the engine 12, the power source control portion 92 establishes an engine drive mode, that is, an HEV drive mode as a drive mode. The HEV drive mode is a hybrid drive mode in which engine travel, that is, hybrid travel (= HEV travel) in which at least the engine 12 is used as the power source SP to travel with the clutch for engine disconnection / connection in an engaged state can be performed. On the other hand, even in a case where the required drive torque Trdem can be satisfied by only the output of the rotating electric machine MG, in a case where charging of the battery 54 is required, preheating of the engine 12 or the like is required, or the like, the power source control portion 92 establishes the HEV drive mode as a drive mode.

[0098] The transmission control portion 94 performs a shift determination of the automatic transmission 22 using a predetermined relationship, i.e., a shift map, for example, and outputs a CB hydraulic control command signal Scb for performing a shift control of the automatic transmission 22 to the hydraulic control circuit 56 as needed, i.e., according to a result of the shift determination. The shift map is a predetermined relationship having a shift line for determining a shift of the automatic transmission 22 on a two-dimensional coordinate with a vehicle speed V and a required drive torque Trdem as variables, for example. In the shift map, the AT output speed No or the like can be used instead of the vehicle speed V, and the required drive force Fredem, the accelerator opening degree θacc, the throttle opening degree θth, or the like can be used instead of the required drive torque Trdem.

[0099] The LU clutch control portion 96 is a lock-up clutch control member, i.e., a lock-up clutch control portion, which controls the LU clutch 36, i.e., controls a control state of the LU clutch 36, so as to become any one of a released state, a slipping state, and an engaged state. Specifically, the LU clutch control portion 96 performs a control region determination using a predetermined relationship, i.e., a lock-up region map, for example, and outputs an LU hydraulic control command signal Slu to the hydraulic control circuit 56, the LU hydraulic control command signal Slu being a signal for supplying the LU clutch 36 with an LU hydraulic pressure PRlu that achieves a control state corresponding to the determined control region.

[0100] Figure 3 FIG. 6 is a view showing an example of the lock-up region map used in the control of the LU clutch 36. In the example of the lock-up region map shown in FIG. 6, the lock-up region map is a predetermined relationship having a released region corresponding to the released state, a slipping region corresponding to the slipping state, and a lock-up region corresponding to the engaged state on a two-dimensional coordinate with a vehicle speed V and an accelerator opening degree θacc as variables, for example. Figure 3 In the example of the lock-up region map shown in FIG. 6, the lock-up region map is a predetermined relationship having a released region corresponding to the released state, a slipping region corresponding to the slipping state, and a lock-up region corresponding to the engaged state on a two-dimensional coordinate with a vehicle speed V and an accelerator opening degree θacc as variables, for example. Figure 3 In the lock-up region map, the AT output speed No or the like can be used instead of the vehicle speed V, and the required drive torque Trdem or the like can be used instead of the accelerator opening degree θacc.

[0101] In a case where it is determined that the control region is the lock-up region, the LU clutch control portion 96 sets the LU hydraulic pressure PRlu for obtaining an LU torque Tlu capable of transmitting an input torque Tinlu to the LU clutch 36, and performs a lock-up control of the LU clutch 36 that sets the LU clutch 36 to the fully engaged state. The input torque Tinlu to the LU clutch 36 is a torque of the power source SP, for example. The LU torque Tlu capable of transmitting the input torque Tinlu is a torque value obtained by multiplying the input torque Tinlu by a safety factor (>1), for example.

[0102] When the LU torque Tlu is smaller than the LU input torque Tinlu, slip occurs in the LU clutch 36. In a case where it is determined that the control region is the slip region, the LU clutch control section 96 sets the LU hydraulic pressure PRlu for achieving a target LU slip amount Nslplut that is a target value of the slip amount of the LU clutch 36, that is, the LU slip amount Nslplu, with respect to the LU input torque Tinlu, and performs slip control of the LU clutch 36, that is, LU slip control, which sets the LU clutch 36 to a target slip state. The target slip state of the LU clutch 36 is a target slip state that achieves the target LU slip amount Nslplut. That is, the LU clutch control section 96 sets the LU clutch command pressure Splu that achieves the target LU slip amount Nslplut, and performs the LU slip control that controls the LU clutch 36 in such a manner as to become a slip state. The LU slip amount Nslplu is a speed difference (=Ne-Nt) between the LU input speed (=engine speed Ne) and the LU output speed (=turbine speed Nt). In the LU slip control, the LU clutch 36 is controlled in such a manner as to become a slip state, and the LU slip amount Nslplu is controlled to the target LU slip amount Nslplut. The LU slip control is performed in the slip region of the lockup region line map. Figure 3 The slip region is set in a low vehicle speed region, for example, compared with the lockup region, is a region in which it is difficult to perform lockup control, and is a region for achieving improvement in energy efficiency, improvement in drivability, and the like by being set to a slip state. In addition, the slip region is also a region that is set in consideration of drivability, roar, and the like (for example, NV (noise, vibration) performance).

[0103] As the automatic driving, the follow-up travel control section 98 executes follow-up travel. In the follow-up travel, autonomous travel is performed without the acceleration / deceleration operation of the driver, and follow-up travel control is executed in which follow-up travel is performed while maintaining the target inter-vehicle distance Dt set by the automatic cruise setting device 82. In the follow-up travel control, the follow-up travel control section 98 controls follow-up travel in which the vehicle is automatically driven at a distance of the target inter-vehicle distance Dt from the preceding vehicle. That is, in the follow-up travel control, the follow-up travel control section 98 performs follow-up travel while maintaining the target inter-vehicle distance Dt from the preceding vehicle. In the follow-up travel control, the follow-up travel control section 98 calculates a required drive torque Trdem required for follow-up travel in a state in which the inter-vehicle distance Dis is the target inter-vehicle distance Dt, and controls the torque of the power source SP so as to be able to obtain the required drive torque Trdem. The target inter-vehicle distance Dt is set variably, for example, in accordance with the vehicle speed V and the like. The required drive torque Trdem is calculated, for example, on the basis of feedback control, feedforward control, and the like of the difference between the target inter-vehicle distance Dt and the actual inter-vehicle distance Dis. In addition, in a case where the required drive torque Trdem is negative (minus sign) at the time of deceleration of the preceding vehicle and the like, the follow-up travel control section 98 generates engine braking, regenerative braking by the rotary machine MG, or, if necessary, braking force of the wheel brake 59 controlled by the wheel brake device 58, so as to be able to obtain the negative required drive torque Trdem. Furthermore, in this follow-up travel, the transmission control section 94 also executes shift control of switching the gear stage of the automatic transmission 22 in accordance with the shift map and the like.

[0104] In the above-described follow-up travel, the preceding vehicle becomes a wind shield, and the air flow to the vehicle 10 is reduced by collision. Therefore, the travel resistance in the vehicle 10 is reduced, and on the other hand, the cooling performance of the radiator 62 in the cooling system 60 is reduced, and further, the cooling performance of the heat exchanger 66 is reduced. In this way, the oil temperature THoil easily rises, and it is possible that the oil temperature THoil becomes excessively high and causes deterioration of the oil FLD. When the oil temperature THoil becomes high during the follow-up travel, it is desirable that the follow-up travel is not aborted or the oil temperature THoil is suppressed from rising without lengthening the inter-vehicle distance Dis while maintaining the target inter-vehicle distance Dt.

[0105] Therefore, during execution of the follow-up travel based on the follow-up travel control of the follow-up travel control section 98, the LU clutch control section 96 executes the oil temperature suppression control CTtho in which the control state of the LU clutch 36 is changed so as to suppress the rise of the oil temperature THoil.

[0106] In the control state of the LU clutch 36, in the engaged state where the LU slip amount Nslplu is zero, the amount of heat from the torque converter 20 is the least. Therefore, when the LU clutch 36 is controlled to the released state or the slipping state during execution of the follow-up running, the LU clutch control portion 96 switches the LU clutch 36 to the engaged state. When the LU clutch 36 is controlled to the engaged state during execution of the follow-up running, the LU clutch control portion 96 maintains the engaged state. That is, the oil temperature suppression control CTtho is control to directly maintain the LU clutch 36 controlled to the engaged state based on the lock-up region map (refer to FIG. 6), and is control to switch the LU clutch 36 controlled to the released state or the slipping state based on the lock-up region map to the engaged state, that is, lock-up on. Figure 3 ) to the engaged state, and is control to switch the LU clutch 36 controlled to the released state or the slipping state based on the lock-up region map to the engaged state, that is, lock-up on.

[0107] Specifically, the follow-up running control portion 98 determines whether or not it is during execution of the follow-up running. When it is determined by the follow-up running control portion 98 that it is not during execution of the follow-up running, the LU clutch control portion 96 does not execute the oil temperature suppression control CTtho. Therefore, when it is during execution of the oil temperature suppression control CTtho and it is determined by the follow-up running control portion 98 that it is not during execution of the follow-up running based on the follow-up running control portion 98, the LU clutch control portion 96 ends the oil temperature suppression control CTtho and does not execute the oil temperature suppression control CTtho.

[0108] When it is determined by the follow-up running control portion 98 that it is during execution of the follow-up running, the LU clutch control portion 96 sets a threshold value for determining whether or not to execute the oil temperature suppression control CTtho, that is, an oil temperature threshold value THf as a prescribed oil temperature. Then, the LU clutch control portion 96 determines whether or not the oil temperature THoil is equal to or higher than the oil temperature threshold value THf.

[0109] The LU clutch control portion 96 executes the oil temperature suppression control CTtho to reduce the amount of heat from the torque converter 20 when it is determined that the oil temperature THoil is equal to or higher than the oil temperature threshold value THf. On the other hand, the LU clutch control portion 96 does not execute the oil temperature suppression control CTtho when it is determined that the oil temperature THoil is lower than the oil temperature threshold value THf. In addition, the LU clutch control portion 96 ends the oil temperature suppression control CTtho and does not execute the oil temperature suppression control CTtho when it is determined that the oil temperature THoil is lower than the oil temperature threshold value THf during execution of the oil temperature suppression control CTtho.

[0110] If the vehicle state is such that the oil temperature THoil is likely to rise, it is preferable to execute the oil temperature suppression control CTtho in advance. The lower the oil temperature THoil is likely to rise, the lower the oil temperature threshold value THf set by the LU clutch control portion 96.

[0111] The longer the inter-vehicle distance Dis with respect to the preceding vehicle, the greater the air flow colliding with the vehicle 10, the greater the cooling performance in the oil cooling system 60 based on air, and the more difficult the oil temperature THoil rises. In other words, the shorter the inter-vehicle distance Dis, the less the air flow colliding with the vehicle 10, the lower the cooling performance in the cooling system 60, and the easier the oil temperature THoil rises. In this way, the easiness of the oil temperature THoil to rise varies depending on the inter-vehicle distance Dis with respect to the preceding vehicle. Therefore, for example, as shown in FIG. 9, the shorter the inter-vehicle distance Dis, the lower value the LU clutch control section 96 sets as the oil temperature threshold THf. Figure 4 Figure 4 FIG. 10 is a diagram showing an example of a preset relationship for setting the oil temperature threshold THf based on the inter-vehicle distance Dis, for example.

[0112] The larger the projected area Area of the preceding vehicle, the less the air flow colliding with the vehicle 10, the lower the cooling performance in the cooling system 60, and the easier the oil temperature THoil rises. In this way, the easiness of the oil temperature THoil to rise varies depending on the projected area Area of the preceding vehicle. Therefore, for example, as shown in FIG. 11, the larger the projected area Area of the preceding vehicle, the lower value the LU clutch control section 96 sets as the oil temperature threshold THf. Figure 5 Figure 5 FIG. 12 is a diagram showing an example of a preset relationship for setting the oil temperature threshold THf based on the projected area Area of the preceding vehicle, for example.

[0113] The wider the preceding vehicle width Wid, the less the air flow colliding with the vehicle 10, the lower the cooling performance in the cooling system 60, and the easier the oil temperature THoil rises. In this way, the easiness of the oil temperature THoil to rise varies depending on the preceding vehicle width Wid. Therefore, for example, as shown in FIG. 13, the wider the preceding vehicle width Wid, the lower value the LU clutch control section 96 sets as the oil temperature threshold THf. Figure 6 Figure 6 FIG. 14 is a diagram showing an example of a preset relationship for setting the oil temperature threshold THf based on the preceding vehicle width Wid, for example.

[0114] ​​​If the environment of the travel route expected in the future, that is, the expected travel route, is different, the easiness of the increase in the oil temperature THoil is different. For example, when the environment of the expected travel route is a travel route in which an uphill road is more, the vehicle load expected in the future, that is, the expected load Loadex, is likely to be large. The larger the expected load Loadex is, the more the required drive torque Tr is likely to increase, and therefore, the frequency of setting the LU clutch 36 to the released state in a manner so as to be able to obtain the torque conversion in the torque converter 20 is increased. When the frequency of setting the LU clutch 36 to the released state is increased, the oil temperature THoil is likely to increase. In this way, the easiness of the increase in the oil temperature THoil varies depending on the expected load Loadex. Therefore, the LU clutch control portion 96 acquires road information in the navigation information Inavi as the environment information of the expected travel route, and calculates the expected load Loadex based on the road information of the expected travel route. Then, for example, as shown in FIG. 8, the larger the expected load Loadex is, the lower the oil temperature threshold THf is set by the LU clutch control portion 96. Figure 7 Figure 7 is a view showing an example of a preset relationship for setting the oil temperature threshold THf based on the expected load Loadex.

[0115] Alternatively, in the expected travel route, for example, when the outside air temperature is high, the oil temperature THoil is likely to increase. The LU clutch control portion 96 acquires climate information in the navigation information Inavi as the environment information of the expected travel route, and the higher the outside air temperature on the expected travel route is, the lower the oil temperature threshold THf is set.

[0116] Alternatively, in the expected travel route, for example, when there is congestion, the oil temperature THoil is likely to increase. The LU clutch control portion 96 acquires traffic information in the navigation information Inavi as the environment information of the expected travel route, and the higher the degree of congestion on the expected travel route is, the lower the oil temperature threshold THf is set.

[0117] In this way, the easiness of the increase in the oil temperature THoil varies depending on the environment of the expected travel route. The LU clutch control portion 96 sets the oil temperature threshold THf based on the environment information of the expected travel route.

[0118] ​In a case where it is determined by the follow-up travel control section 98 that it is in the execution period of follow-up travel, the LU clutch control section 96 acquires, as the vehicle surrounding information Iard, the inter-vehicle distance Dis with respect to the preceding vehicle, the projected area Area of the preceding vehicle, the preceding vehicle width Wid, and the like. In addition, in a case where it is determined by the follow-up travel control section 98 that it is in the execution period of follow-up travel, the LU clutch control section 96 acquires the expected travel route of the vehicle 10 based on the navigation information Inavi, and acquires the environmental information of the expected travel route.

[0119] The LU clutch control section 96 sets the oil temperature threshold value THf based on the vehicle surrounding information Iard and the environmental information of the expected travel route. For example, the LU clutch control section 96 sets the lowest oil temperature threshold value THf among the oil temperature threshold values THf respectively calculated based on the vehicle surrounding information Iard and the environmental information of the expected travel route as the oil temperature threshold value THf for determining whether to execute the oil temperature suppression control CTtho.

[0120] In the oil temperature suppression control CTtho, for example, in a case where the LU clutch 36 controlled to the release state based on the lock-up region line map is switched to the lock-up on, the torque amplification effect cannot be obtained in the torque converter 20. In this way, it is possible that the follow-up travel control section 98 is unable to achieve the required drive torque Trdem required for follow-up travel, and it is possible that follow-up travel is unable to be appropriately continued. The follow-up travel control section 98 determines whether the execution of follow-up travel becomes difficult due to a change in travel performance caused by the oil temperature suppression control CTtho. In a case where it is determined that the execution of follow-up travel becomes difficult, the follow-up travel control section 98 suspends follow-up travel, and ends follow-up travel.

[0121] Figure 8 is a flowchart that explains the main part of the control work of the electronic control device 90, and is a flowchart that explains the control work for suppressing the rise in the oil temperature THoil caused by the decrease in the cooling performance of the heat exchanger 66 while appropriately maintaining follow-up travel, for example, is repeatedly executed.

[0122] In Figure 8In this case, first, in a step (hereinafter, "step" is omitted) S10 corresponding to the function of the follow-up travel control section 98, it is determined whether or not it is during execution of the follow-up travel. In the affirmative case of this S10, in an S20 corresponding to the function of the LU clutch control section 96, as the vehicle surrounding information Iard, the inter-vehicle distance Dis with respect to the preceding vehicle, the projected area Area of the preceding vehicle, the preceding vehicle width Wid, and the like are acquired. Next, in an S30 corresponding to the function of the LU clutch control section 96, as the environmental information of the expected travel route, the road information, the weather information, the traffic information, and the like are acquired. Next, in an S40 corresponding to the function of the LU clutch control section 96, the oil temperature threshold THf is set based on the vehicle surrounding information Iard and the environmental information of the expected travel route. Next, in an S50 corresponding to the function of the LU clutch control section 96, it is determined whether or not the oil temperature THoil is equal to or higher than the oil temperature threshold THf. In the affirmative case of this S50, in an S60 corresponding to the function of the LU clutch control section 96, it is determined whether or not the control state of the LU clutch 36 is the release state. In the negative case of this S60, in an S70 corresponding to the function of the LU clutch control section 96, it is determined whether or not the control state of the LU clutch 36 is the slip state. In the negative case of this S70, the present routine ends. In the affirmative case of the above S60, or in the affirmative case of the above S70, in an S80 corresponding to the function of the LU clutch control section 96, the control state of the LU clutch 36 is switched to the lock-up ON. Next, in an S90 corresponding to the function of the follow-up travel control section 98, it is determined whether or not execution of the follow-up travel is difficult, and in particular, whether or not it is impossible to execute the follow-up travel. In the negative case of this S90, the present routine ends. In the affirmative case of this S90, in an S100 corresponding to the function of the follow-up travel control section 98, the follow-up travel is ended. In the negative case of the above S10, or in the negative case of the above S50, in an S110 corresponding to the function of the LU clutch control section 96, the oil temperature suppression control CTtho is not executed.

[0123] As described above, according to the present embodiment, since the oil temperature suppression control CTtho is executed during execution of the follow-up travel, in which the control state of the LU clutch 36 is changed so as to suppress the rise of the oil temperature THoil, it is possible to reduce the heat generation amount from the torque converter 20 including the LU clutch 36 without changing the actual inter-vehicle distance Dis with respect to the target inter-vehicle distance Dt in the follow-up travel. Therefore, it is possible to suppress the rise of the oil temperature THoil due to the reduction of the cooling performance of the heat exchanger 66 while appropriately maintaining the follow-up travel.

[0124] In addition, according to the present embodiment, since the oil temperature suppression control CTtho is control to switch the LU clutch 36 controlled to the released state or the slipping state based on the lock-up region map to the engaged state, the heat amount from the torque converter 20 can be appropriately reduced.

[0125] In addition, according to the present embodiment, the lower the easiness of the oil temperature THoil to rise, the lower the oil temperature threshold THf is set, and in a case where it is determined that the oil temperature THoil is equal to or higher than the oil temperature threshold THf, the oil temperature suppression control CTtho is executed to reduce the heat amount from the torque converter 20, so the oil temperature suppression control CTtho can be executed in advance when in a state where the oil temperature THoil is easy to rise, and the rise of the oil temperature THoil can be suppressed.

[0126] In addition, according to the present embodiment, the easiness of the oil temperature THoil to rise varies according to the environment of the expected travel route, and the oil temperature threshold THf is set based on the environment information of the expected travel route, so the oil temperature suppression control CTtho can be executed in advance when in a state where the oil temperature THoil is easy to rise due to the environment of the expected travel route.

[0127] In addition, according to the present embodiment, the expected load Loadex is calculated based on the environment information of the expected travel route, and the larger the expected load Loadex, the lower the oil temperature threshold THf is set, so the oil temperature suppression control CTtho can be executed in advance when in a state where the oil temperature THoil is easy to rise due to the expected load Loadex being large.

[0128] In addition, according to the present embodiment, the easiness of the oil temperature THoil to rise varies according to the inter-vehicle distance Dis with respect to the preceding vehicle, and the shorter the inter-vehicle distance Dis, the lower the oil temperature threshold THf is set, so the oil temperature suppression control CTtho can be executed in advance when in a state where the cooling performance based on air is reduced due to the inter-vehicle distance Dis being short.

[0129] In addition, according to the present embodiment, the easiness of the oil temperature THoil to rise varies according to the projected area Area of the preceding vehicle, and the larger the projected area Area of the preceding vehicle, the lower the oil temperature threshold THf is set, so the oil temperature suppression control CTtho can be executed in advance when in a state where the cooling performance based on air is reduced due to the projected area Area being large.

[0130] In addition, according to the present embodiment, the easiness of the increase in the oil temperature THoil varies depending on the preceding vehicle width Wid, and the wider the preceding vehicle width Wid, the lower the value of the oil temperature threshold THf is set to, and thus, when the state in which the cooling performance based on air is reduced due to the wide preceding vehicle width Wid, the oil temperature suppression control CTtho can be executed in advance.

[0131] In addition, according to the present embodiment, in a case where it is determined that the execution of the follow driving becomes difficult due to the change in the running performance caused by the oil temperature suppression control CTtho, the follow driving is suspended, and thus, the increase in the oil temperature THoil caused by the follow driving can be avoided.

[0132] In addition, according to the present embodiment, when the follow driving ends during the execution of the oil temperature suppression control CTtho, the oil temperature suppression control CTtho is ended, and thus, the oil temperature suppression control CTtho is not executed when the follow driving is not executed, and the control of the vehicle 10 as a whole can be simplified. In addition, when the follow driving is not executed, the control state of the LU clutch 36 is not restricted with respect to the increase in the oil temperature THoil.

[0133] Next, other embodiments of the present application will be described. Furthermore, in the following description, the same reference numerals are attached to the portions commonly used in the embodiments, and the description will be omitted.

[0134] Embodiment 2

[0135] In the above-described embodiment 1, the same oil temperature threshold THf is used in the start determination and the end determination of the oil temperature suppression control CTtho. In the present embodiment, different oil temperature thresholds THf are used in the start determination and the end determination of the oil temperature suppression control CTtho.

[0136] The LU clutch control section 96 sets the control end threshold THfoff used in the end determination of the oil temperature suppression control CTtho to a value lower than the control start threshold THfon used in the start determination of the oil temperature suppression control CTtho. As the control start threshold THfon, the LU clutch control section 96 sets, for example, the oil temperature threshold THf set in the above-described embodiment 1. In addition, as the control end threshold THfoff, the LU clutch control section 96 sets, for example, a value lower than the control start threshold THfon by a hunting suppression value set in advance.

[0137] In a case where it is determined by the follow-up travel control section 98 that it is during execution of follow-up travel, the LU clutch control section 96 sets the control start threshold THfon and the control end threshold THfoff. Then, the LU clutch control section 96 determines whether the oil temperature THoil is equal to or higher than the control start threshold THfon. In a case where it is determined that the oil temperature THoil is equal to or higher than the control start threshold THfon, the LU clutch control section 96 executes the oil temperature suppression control CTtho. In addition, the LU clutch control section 96 determines whether the oil temperature THoil is equal to or lower than the control end threshold THfoff during execution of the oil temperature suppression control CTtho. In a case where it is determined that the oil temperature THoil is equal to or lower than the control end threshold THfoff, the LU clutch control section 96 ends the oil temperature suppression control CTtho.

[0138] Figure 9 is a flowchart that explains the main part of the control operation of the electronic control device 90, and is a flowchart that explains the control operation for suppressing the rise in the oil temperature THoil caused by the decrease in the cooling performance of the heat exchanger 66 while appropriately maintaining follow-up travel, for example, is repeatedly executed. Figure 9 is an embodiment that is different from Figure 8 the flowchart. Figure 9 In Figure 8 , the points different from Figure 10 is an example of a timing chart in a case where the control operation shown in the flowchart of Figure 9 is executed.

[0139] In Figure 9 , instead of the S40, in the S40B corresponding to the function of the LU clutch control section 96, the control start threshold THfon and the control end threshold THfoff are set. Next, instead of the S50, in the S50B corresponding to the function of the LU clutch control section 96, it is determined whether the oil temperature THoil is equal to or higher than the control start threshold THfon. In a case where the determination of the S50B is negative, in the S55 corresponding to the function of the LU clutch control section 96, it is determined whether it is during execution of the oil temperature suppression control CTtho. In a case where the determination of the S55 is affirmative, in the S58 corresponding to the function of the LU clutch control section 96, it is determined whether the oil temperature THoil is equal to or lower than the control end threshold THfoff. In a case where the determination of the S55 is negative, or in a case where the determination of the S58 is affirmative, the S110 is executed. In a case where the determination of the S50B is affirmative, or in a case where the determination of the S58 is negative, the S60 is executed.

[0140] Figure 10An example of a change in the oil temperature THoil during execution of the follow-up running, i.e., when the follow-up running is executed, is shown. In Figure 10 , the t1 point of time shows a point of time at which the oil temperature THoil becomes equal to or higher than the control start threshold THfon during execution of the follow-up running. Along with this, the oil temperature suppression control CTtho becomes the ON state, i.e., is executed, and the control state of the LU clutch 36 is switched from the released state to the lock-up ON (refer to the t1 point of time to the t2 point of time). When the oil temperature THoil is lowered by execution of the oil temperature suppression control CTtho and the oil temperature THoil becomes lower than the control end threshold THfoff, the oil temperature suppression control CTtho is made the OFF state, i.e., the oil temperature suppression control CTtho is ended, and the control state of the LU clutch 36 is switched to the released state (refer to the point of time after the t2 point of time). In Figure 10 , the control state of the LU clutch 36 is switched to the released state along with the end of the oil temperature suppression control CTtho, but after the oil temperature suppression control CTtho is ended, it is sufficient to return the control state of the LU clutch 36 to the normal control based on the lock-up region map (refer to Figure 3 ), and it is not necessarily required to be set to the released state.

[0141] As described above, according to the present embodiment, during execution of the oil temperature suppression control CTtho, in a case where it is determined that the oil temperature THoil is lower than the control end threshold THfoff which is set to a value lower than the control start threshold THfon, the oil temperature suppression control CTtho is ended, and thus, hunting in which the start and end of the oil temperature suppression control CTtho are repeated in a short time can be avoided, and the oil temperature suppression control CTtho can be ended after the rise in the oil temperature THoil is sufficiently suppressed.

[0142] Embodiment 3

[0143] In the above-described embodiment 1, the oil temperature suppression control CTtho is control for switching the LU clutch 36 which is controlled to the released state or the slipping state based on the lock-up region map (refer to Figure 3 ) to the engaged state. The amount of heat generation from the torque converter 20 is largest in the slipping state, and in the case of the released state and the engaged state, sometimes there is little difference. In such a case, it is also possible to set the LU clutch 36 which is controlled to the slipping state to the released state in which the torque amplification effect can be obtained in the torque converter 20.

[0144] In the present embodiment, when the LU clutch 36 is controlled to the slip state during execution of the follow-up running, the LU clutch control section 96 switches the LU clutch 36 to the released state. That is, the oil temperature suppression control CTtho is control that switches the LU clutch 36 controlled to the released state based on the lock-up region map to the engaged state and switches the LU clutch 36 controlled to the slip state based on the lock-up region map to the released state.

[0145] Figure 11 is a flowchart that explains the main part of the control operation of the electronic control device 90, and is a flowchart that explains the control operation for suppressing the rise in the oil temperature THoil caused by the decrease in the cooling performance of the heat exchanger 66 while appropriately maintaining the follow-up running, for example, is repeatedly executed. Figure 11 is a flowchart different from Figure 8 of the flowchart. In Figure 11 , the points different from Figure 8 are mainly described.

[0146] In Figure 11 , in the case where the determination of the S60 is negative, the S70 is executed. In the case where the determination of the S70 is affirmative, in the S75 corresponding to the function of the LU clutch control section 96, the control state of the LU clutch 36 is switched to the released state. In the case where the determination of the S60 is affirmative, the S80 is executed. After the above S75 or the S80, the S90 is executed.

[0147] As described above, according to the present embodiment, since the oil temperature suppression control CTtho is control that switches the LU clutch 36 controlled to the released state based on the lock-up region map to the engaged state and switches the LU clutch 36 controlled to the slip state based on the lock-up region map to the released state, it is possible to appropriately reduce the heat generation amount from the torque converter 20.

[0148] Embodiment 4

[0149] In the above-described embodiment 1, in the case where it is determined that the execution of the follow-up running becomes difficult, the follow-up running is discontinued. At this time, since the follow-up running is discontinued, the operation of acceleration and deceleration and the like by the driver is required, and therefore, in order to smoothly shift to the operation by the driver, it can also be required that the driver performs the confirmation of the discontinuation of the follow-up running.

[0150] When it is determined that execution of the follow-up travel becomes difficult, the follow-up travel control section 98 suspends the follow-up travel after there is an instruction or an approval of the driver, and ends the follow-up travel. For example, when it is determined that execution of the follow-up travel becomes difficult, the follow-up travel control section 98 displays a situation in which it is not possible to continue the follow-up travel on a monitor or the like in the vehicle, and thereby notifies the driver. The follow-up travel control section 98 determines whether or not the driver has instructed or approved the end of the follow-up travel, for example, based on a driver operation on the monitor or the like in the vehicle. In a case where it is determined that the driver has instructed or approved the end of the follow-up travel, the follow-up travel control section 98 suspends the follow-up travel, and ends the follow-up travel.

[0151] Figure 12 is a flowchart that explains the main part of the control operation of the electronic control device 90, and is a flowchart that explains the control operation for suppressing an increase in the oil temperature THoil caused by a decrease in the cooling performance of the heat exchanger 66 while appropriately maintaining the follow-up travel, and is repeatedly executed, for example. Figure 12 is a flowchart different from Figure 8 . In Figure 12 , mainly the difference from Figure 8 is described.

[0152] In Figure 12 , in a case where the determination of the S90 is affirmative, in the S95 corresponding to the function of the follow-up travel control section 98, the driver is notified that it is not possible to execute the follow-up travel. Next, in the S98 corresponding to the function of the follow-up travel control section 98, it is determined whether or not the driver has instructed or approved the end of the follow-up travel. In a case where the determination of the S98 is negative, the S98 is repeatedly executed. In a case where the determination of the above S98 is affirmative, the S100 is executed.

[0153] As described above, according to the present embodiment, when it is determined that execution of the follow-up travel becomes difficult, the follow-up travel is suspended after there is an instruction or an approval of the driver, and thus it is possible to appropriately shift from the follow-up travel of the automatic travel to the travel based on the driver operation.

[0154] Embodiment 5

[0155] In a case where a failure occurs in the torque converter 20 including the LU clutch 36 and a device or the like associated with the control of the torque converter 20, it can be impossible to appropriately control the LU clutch 36 and to appropriately control the oil temperature suppression control CTtho. The device associated with the control of the torque converter 20 is, for example, the hydraulic control circuit 56, the electronic control device 90.

[0156] In a case where a failure of any one of the torque converter 20 and the devices associated with the control of the torque converter 20 is detected, the LU clutch control section 96 prohibits the oil temperature suppression control CTtho. In addition, in a case where a failure of any one of the torque converter 20 and the devices associated with the control of the torque converter 20 is detected, the LU clutch control section 96 can also set the LU clutch 36 to the released state.

[0157] Figure 13 is a flowchart that explains the main part of the control operation of the electronic control device 90, and is a flowchart that explains the control operation for suppressing the rise in the oil temperature THoil caused by the decrease in the cooling performance of the heat exchanger 66 while appropriately maintaining follow-up running, for example, is repeatedly executed. Figure 13 is a flowchart different from Figure 8 of the flowchart of Figure 13 , the difference from Figure 8 is mainly described.

[0158] In Figure 13 , in S5 corresponding to the function of the LU clutch control section 96, it is determined whether a failure of any one of the torque converter 20 and the devices associated with the control of the torque converter 20 is detected. In a case where the determination of this S5 is affirmative, in S8 corresponding to the function of the LU clutch control section 96, the oil temperature suppression control CTtho is prohibited, and the LU clutch 36 is set to the released state. In a case where the determination of the above S5 is negative, the above S10 is executed.

[0159] As described above, according to the present embodiment, in a case where a failure of any one of the torque converter 20 and the devices associated with the control of the torque converter 20 is detected, the oil temperature suppression control CTtho is prohibited, and thus, when it is possible that the control state of the LU clutch 36 cannot be appropriately changed, the oil temperature suppression control CTtho is not executed.

[0160] The above-described embodiments of the present application have been described in detail based on the drawings, but the present application can also be applied in other forms.

[0161] For example, two or more of the above-described Embodiments 2 to 5 can be combined with the above-described Embodiment 1 and executed.

[0162] In addition, in the above-described embodiments, the oil temperature threshold THf can not necessarily need to be set based on the vehicle surrounding information Iard and the environmental information of the expected travel route, and can be a value that can suppress the rise in the oil temperature THoil, which is set in advance. In addition, the oil temperature threshold THf can be set based on one of the vehicle surrounding information Iard or one of the environmental information of the expected travel route.

[0163] In addition, in the above-described embodiment, the heat exchanger 66 can not be provided Figure 8 S90, S100, and the like in the flowchart, can be appropriately changed Figure 8 the flowchart.

[0164] In addition, in the above-described embodiment, the heat exchanger 66 can be, for example, an oil cooler in which a radiator for air direct collision is built in.

[0165] Furthermore, the above-described content is merely one embodiment, and the present application can be implemented in various forms to which various changes and modifications based on the knowledge of those skilled in the art are applied.

Claims

1. A control device (90) of a vehicle (10) that is provided with a power source (12, MG, SP) and a fluid-type transmission (20) provided in a power transmission path between the power source (12, MG, SP) and a drive wheel (14) and having a lock-up clutch (36), characterized by, the control device (90) of the vehicle (10) comprising: a following travel control section (98) that controls following travel in which the vehicle (10) is automatically traveled at a prescribed inter-vehicle distance from a preceding vehicle; and a lock-up clutch control section (96) that controls the lock-up clutch (36) to any one of a release state, a slip state, and an engagement state, the lock-up clutch control section (96) executing oil temperature suppression control in which the control state of the lock-up clutch (36) is changed so as to suppress a temperature rise of working oil (FLD) that circulates within the fluid-type transmission (20) and is used in switching of the control state of the lock-up clutch (36) during execution of the following travel, the lock-up clutch control section (96) setting a lower prescribed oil temperature as the temperature of the working oil (FLD) is more likely to rise, the oil temperature suppression control being executed so as to cause a heat generation amount from the fluid-type transmission (20) to decrease in a case where it is determined that the temperature of the working oil (FLD) is the prescribed oil temperature or more, the temperature rise likelihood of the working oil (FLD) varying in accordance with the inter-vehicle distance from the preceding vehicle, and the lock-up clutch control section (96) setting the prescribed oil temperature to a lower value as the inter-vehicle distance is shorter.

2. The control device (90) of the vehicle (10) according to claim 1, characterized in that, the oil temperature suppression control is control that switches the lock-up clutch (36) that is controlled to the release state or the slip state based on a preset relationship to the engagement state.

3. A control device (90) of a vehicle (10) that is provided with a power source (12, MG, SP) and a fluid-type transmission (20) provided in a power transmission path between the power source (12, MG, SP) and a drive wheel (14) and having a lock-up clutch (36), characterized by, the control device (90) of the vehicle (10) comprising: a following travel control section (98) that controls following travel in which the vehicle (10) is automatically traveled at a prescribed inter-vehicle distance from a preceding vehicle; and a lock-up clutch control section (96) that controls the lock-up clutch (36) to any one of a release state, a slip state, and an engagement state, ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The lock-up clutch control section (96) executes oil temperature suppression control in which the control state of the lock-up clutch (36) is changed so as to suppress a temperature rise of working oil (FLD) circulating within the fluid-type transmission (20) and used in switching of the control state of the lock-up clutch (36) during execution of the follow-up running, The oil temperature suppression control is control that switches the lock-up clutch (36) controlled to the release state based on a predetermined relationship to the engaged state and switches the lock-up clutch (36) controlled to the slip state based on the relationship to the release state.

4. The control device (90) of the vehicle (10) according to claim 3, characterized in that The lower the temperature rise of the working oil (FLD), the lower the prescribed oil temperature set by the lock-up clutch control section (96), and in a case where it is determined that the temperature of the working oil (FLD) is the prescribed oil temperature or higher, the oil temperature suppression control is executed so as to reduce the amount of heat generated from the fluid-type transmission (20).

5. The control device (90) of the vehicle (10) according to claim 4, characterized in that The temperature rise of the working oil (FLD) varies according to an environment of a travel route anticipated in future travel, The lock-up clutch control section (96) sets the prescribed oil temperature based on environment information of the travel route.

6. The control device (90) of the vehicle (10) according to claim 5, characterized in that The lock-up clutch control section (96) calculates a vehicle load anticipated in future travel based on the environment information of the travel route, and the greater the vehicle load, the lower the value set as the prescribed oil temperature.

7. The control device (90) of the vehicle (10) according to claim 4, characterized in that The temperature rise of the working oil (FLD) varies according to an inter-vehicle distance with respect to the preceding vehicle, The shorter the inter-vehicle distance, the lower the value set as the prescribed oil temperature by the lock-up clutch control section (96).

8. The control device (90) of the vehicle (10) according to claim 4, characterized in that The temperature rise of the working oil (FLD) varies according to a projected area of the preceding vehicle, The greater the projected area when viewed from behind the preceding vehicle, the lower the value set as the prescribed oil temperature by the lock-up clutch control section (96).

9. The control device (90) of the vehicle (10) according to claim 4, characterized in that The temperature rise of the working oil (FLD) varies according to a vehicle dimension in a direction orthogonal to the advancing direction of the preceding vehicle, that is, a width of the preceding vehicle, The wider the width of the preceding vehicle, the lower the value set as the prescribed oil temperature by the lock-up clutch control section (96).

10. The control device (90) of the vehicle (10) according to claim 4, characterized in that The lock-up clutch control section (96) sets a control end threshold value used in the end determination of the oil temperature suppression control to a value lower than the prescribed oil temperature used in the start determination of the oil temperature suppression control, and ends the oil temperature suppression control in a case where it is determined that the temperature of the working oil (FLD) is lower than or equal to the control end threshold value during execution of the oil temperature suppression control.

11. The control device (90) of the vehicle (10) according to claim 3, characterized in that, The follow-up travel control section (98) suspends the follow-up travel in a case where it is determined that execution of the follow-up travel becomes difficult due to a change in travel performance caused by the oil temperature suppression control.

12. The control device (90) of the vehicle (10) according to claim 11, characterized in that, The follow-up travel control section (98) suspends the follow-up travel upon the presence of an instruction or permission of the driver in a case where it is determined that execution of the follow-up travel becomes difficult.

13. The control device (90) of the vehicle (10) according to claim 3, characterized in that, The lock-up clutch control section (96) prohibits the oil temperature suppression control in a case where a failure of any one of the fluid-type power transmission device (20) including the lock-up clutch (36) and a device associated with control of the fluid-type power transmission device (20) is detected.

14. The control device (90) of the vehicle (10) according to claim 3, characterized in that, The lock-up clutch control section (96) ends the oil temperature suppression control in a case where the follow-up travel is ended during execution of the oil temperature suppression control.

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