vehicle

Abstract

To properly improve the fuel efficiency of a hybrid vehicle equipped with a torque converter with an LUC (a lock-up clutch).SOLUTION: In a vehicle, a torque converter with an LUC, an automatic transmission and a motor generator are arranged in this order on a power transmission path extending from an engine to a driving wheel. The vehicle is equipped with an oil temperature sensor that senses the temperature of ATF which is hydraulic oil that is used in the automatic transmission, the LUC and the torque converter, and an ECU. The LUC is engaged when the temperature of the ATF is equal to or above a temperature at which lock-up is possible. The ECU, when the temperature of the ATF is less than the temperature at which lock-up is possible, executes ATF warming-up control by which the ATF is warmed up by increasing output of the engine. The ECU determines whether execution of the ATF warming-up control is permitted or not, using a travelling history of the vehicle including an engagement history of the LUC and a fuel-consumption history of the engine.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to a hybrid vehicle in which a torque converter with a lock-up clutch, an automatic transmission, and a motor generator are provided in this order in a power transmission path from an engine to drive wheels. [Background technology]

[0002] JP 2017-197024 A (Patent Document 1) discloses a hybrid vehicle in which a motor generator and an automatic transmission are provided in this order in a power transmission path from the engine to the drive wheels. In this hybrid vehicle, when the engine is cold, the engine output is increased to increase the engine speed to warm up the engine, and the increased engine output is used to generate regenerative power by the motor generator, thereby recovering part of the energy consumed to warm up the engine. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-197024 A Summary of the Invention [Problem to be solved by the invention]

[0004] In order to obtain a sufficient improvement in fuel economy in a hybrid vehicle, it is desirable to properly warm up not only the engine but also other drive components such as an automatic transmission, etc. If the drive components are not warmed up sufficiently, a state in which friction loss in the drive components is large continues, and the intended improvement in fuel economy may not be obtained.

[0005] In a hybrid vehicle equipped with a torque converter and an automatic transmission with a lock-up clutch, if the automatic transmission is not warmed up sufficiently, not only will friction loss in the automatic transmission increase, but the fuel economy improvement effect of the lock-up function may not be obtained. The lock-up function is a function that reduces loss of driving force by engaging the lock-up clutch to mechanically connect the input element and the output element of the torque converter in a steady driving state (for example, a state in which the vehicle is running at a constant high speed) in which torque amplification by the torque converter is not required. In general, the hydraulic oil used for the engagement of the lock-up clutch and the power transmission of the torque converter is the same as the hydraulic oil (ATF: Automatic Transmission Fluid) used for lubrication, cooling, etc. of the automatic transmission. If the temperature of the ATF is below a predetermined lock-up possible temperature, the engagement of the lock-up clutch is not permitted even in a steady driving state. Therefore, if the automatic transmission is not warmed up sufficiently, the temperature of the ATF will continue to be below the lock-up possible temperature, and the lock-up clutch will not be engaged, making it difficult to obtain the fuel economy improvement effect of the lock-up function.

[0006] In particular, in a hybrid vehicle in which a torque converter with a lock-up clutch, an automatic transmission, and a motor generator are provided in this order in the power transmission path from the engine to the drive wheels, the automatic transmission is in a non-power transmission state (neutral state) and is not driven during a motor drive mode in which the engine is stopped and the vehicle runs using the power of the motor generator. Therefore, there is a concern that the automatic transmission is warmed up less frequently, and the ATF is not heated accordingly, resulting in a decrease in the frequency of engagement of the lock-up clutch.

[0007] The present disclosure has been made to solve the above-mentioned problems, and its purpose is to appropriately improve fuel efficiency in a vehicle in which a torque converter with a lock-up clutch, an automatic transmission, and a motor generator are provided in that order in the power transmission path from the engine to the drive wheels, by appropriately increasing the engagement frequency of the lock-up clutch. [Means for solving the problem]

[0008] (1) A vehicle according to the present disclosure is a vehicle in which a torque converter with a lock-up clutch, an automatic transmission, and a motor generator are provided in this order in a power transmission path from an engine to drive wheels. The vehicle includes an oil temperature sensor that detects the temperature of hydraulic oil used in the automatic transmission, the lock-up clutch, and the torque converter, and a control device that executes temperature increase control to increase the temperature of the hydraulic oil by increasing the engine output when the temperature of the hydraulic oil is below a predetermined temperature. The lock-up clutch is engaged when the temperature of the hydraulic oil is equal to or higher than the predetermined temperature. The control device determines whether or not to permit the execution of temperature increase control using the vehicle's driving history, including the engagement history of the lock-up clutch and the fuel consumption history of the engine.

[0009] According to the above configuration, whether or not to permit the execution of temperature rise control accompanied by fuel consumption is determined using the driving history of the vehicle. This driving history includes the engagement history of the lockup clutch and the fuel consumption history of the engine. Therefore, it is possible to determine whether or not to permit the execution of temperature rise control after determining whether or not it is possible to improve fuel economy by engaging the lockup clutch during a release period in which the lockup clutch has not been engaged in the past. As a result, it is possible to appropriately improve fuel economy by appropriately increasing the engagement frequency of the lockup clutch in the power transmission path from the engine to the drive wheels.

[0010] (2) In one aspect, the control device uses the driving history to calculate the amount of reduction in fuel consumption by the engine due to engaging the lockup clutch during a release period when the lockup clutch is not engaged and the amount of increase in fuel consumption by the engine due to executing temperature increase control. The control device allows the execution of temperature increase control when the amount of reduction in fuel consumption is greater than the amount of increase in fuel consumption, and does not allow the execution of temperature increase control when the amount of reduction in fuel consumption is smaller than the amount of increase in fuel consumption.

[0011] According to the above configuration, when it is expected that fuel economy can be improved by engaging the lockup clutch during the past period in which the lockup clutch was released, execution of the temperature increase control is permitted, thereby making it possible to more appropriately improve fuel economy.

[0012] (3) In one aspect, the lock-up clutch is engaged when the vehicle is in a predetermined driving state and the temperature of the hydraulic oil is higher than a predetermined temperature, and the release period is a period during which the lock-up clutch is released because the vehicle is in the predetermined driving state but the temperature of the hydraulic oil is lower than the predetermined temperature.

[0013] According to the above configuration, the release period that is the basis for calculating the reduction in fuel consumption is limited to the period during which the lock-up clutch is released due to the temperature of the hydraulic oil, not the running state of the vehicle, which makes it possible to more appropriately determine whether or not the execution of the temperature increase control will lead to an improvement in fuel efficiency.

[0014] (4) In one aspect, the vehicle driving modes include a motor driving mode in which the automatic transmission is in a non-power-transmitting state and the vehicle is driven by power from the motor generator. When performing temperature increase control during the motor driving mode, the control device rotates the torque converter by operating the engine while maintaining the automatic transmission in a non-power-transmitting state.

[0015] According to the above-described configuration, the temperature increase control during the motor drive mode operates the engine to rotate the torque converter while maintaining the automatic transmission in a non-power transmitting state, thereby making it possible to increase the temperature of the hydraulic oil without transmitting the output of the engine to the drive wheels.

[0016] (5) In one aspect, when the control device executes temperature increase control during motor driving mode and when the vehicle is decelerating, the control device places the automatic transmission in a power transmission state and rotates the automatic transmission using power transmitted from the drive wheels.

[0017] According to the above configuration, in the motor running mode, the automatic transmission is rotated by the deceleration energy of the vehicle, rather than the output of the engine, thereby making it possible to increase the temperature of the hydraulic oil.

[0018] (6) In one aspect, the vehicle driving modes include a hybrid driving mode in which the automatic transmission is in a power transmission state and the vehicle is driven by at least one of the power of the engine and the motor generator. When executing temperature increase control during the hybrid driving mode, the control device increases the rotation speed of the torque converter and the automatic transmission by increasing the output of the engine, and causes the motor generator to generate regenerative electric power equivalent to the increase in the output of the engine.

[0019] According to the above configuration, by performing temperature rise control during hybrid driving mode, the engine output is increased to raise the temperature of the hydraulic oil, while a portion of the energy consumed to raise the temperature of the hydraulic oil can be recovered as regenerative power. Effect of the Invention

[0020] According to the present disclosure, in a vehicle in which a torque converter with a lock-up clutch, an automatic transmission, and a motor generator are provided in that order in the power transmission path from the engine to the drive wheels, fuel efficiency can be appropriately improved by appropriately increasing the engagement frequency of the lock-up clutch. [Brief description of the drawings]

[0021] [Figure 1] FIG. 1 is an overall configuration diagram of a vehicle. [Diagram 2] 5 is a flowchart showing an example of a processing procedure when an ECU controls engagement of a lock-up clutch. [Diagram 3] 4 is a flowchart showing an example of a processing procedure when an ECU performs ATF temperature increase control. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference characters and the description thereof will not be repeated.

[0023] <Overall composition> 1 is an overall configuration diagram of a vehicle 1 according to this embodiment. The vehicle 1 includes an engine 10, a motor generator (hereinafter also referred to as "MG") 20, a PCU (Power Control Unit) 21, a battery 22, a torque converter 30, an automatic transmission 40, a hydraulic circuit 45, an oil temperature sensor 46, drive wheels 50, and an ECU (Electronic Control Unit) 100. The torque converter 30 includes a pump impeller 31, a turbine runner 32, a stator 33, and a lock-up clutch (LUC) 34.

[0024] The vehicle 1 is a hybrid vehicle in which a torque converter 30 with a lock-up clutch 34, an automatic transmission 40, and an MG 20 are provided in this order on a power transmission path from an engine 10 to drive wheels 50.

[0025] The output shaft 12 of the engine 10 is connected to an input shaft 41 of the automatic transmission 40 via the torque converter 30. More specifically, the output shaft 12 of the engine 10 is connected to a pump impeller 31 of the torque converter 30, and the input shaft 41 of the automatic transmission 40 is connected to a turbine runner 32 of the torque converter 30.

[0026] The output shaft 42 of the automatic transmission 40 is connected to the rotating shaft 35. The rotating shaft 35 is connected to driving wheels 50. The rotor of the MG 20 is connected to the rotating shaft 35.

[0027] The engine 10 is an internal combustion engine such as a gasoline engine or a diesel engine. The MG 20 is driven by high-voltage power supplied from a battery 22 via a PCU 21. The MG 20 generates electricity by being rotated by power transmitted from a rotating shaft 35 (power transmitted from the engine 10 or the driving wheels 50). The battery 22 stores power to be supplied to the MG 20, which operates at high voltage. The PCU 21 converts power between the MG 20 and the battery 22.

[0028] The lock-up clutch 34 of the torque converter 30 is controlled to an engaged state (lock-up state) or a released state (non-lock-up state) based on a control signal from the ECU 100. When the lock-up clutch 34 is in a released state, power is transmitted between the pump impeller 31 and the turbine runner 32 by hydraulic oil, which may cause a rotational speed difference (slip of the torque converter 30) between the pump impeller 31 and the turbine runner 32. When the lock-up clutch 34 is in an engaged state, the pump impeller 31 (input element) and the turbine runner 32 (output element) of the torque converter 30 are mechanically connected to each other and rotate integrally. Therefore, by engaging the lock-up clutch 34, the loss of the driving force transmitted by the torque converter 30 can be reduced.

[0029] The automatic transmission 40 is, for example, a stepped automatic transmission capable of selectively forming a plurality of gears with different gear ratios. The automatic transmission 40 is controlled to a power transmitting state or a non-power transmitting state (neutral state) based on a control signal from the ECU 100. When the automatic transmission 40 is in the power transmitting state, power is transmitted between the input shaft 41 and the output shaft 42 of the automatic transmission 40, and the engine 10 is connected to the MG 20 and the drive wheels 50. When the automatic transmission 40 is in the non-power transmitting state, power is not transmitted between the input shaft 41 and the output shaft 42 of the automatic transmission 40, and the engine 10 is disconnected from the MG 20 and the drive wheels 50.

[0030] The interior of the automatic transmission 40 is filled with ATF (Automatic Transmission Fluid), which is a hydraulic oil used for lubricating and cooling the automatic transmission 40 and for controlling the automatic transmission 40 (switching the gear ratio), etc. The ATF is also used to control the lock-up clutch 34 (switching between engagement and release) and to transmit power between the pump impeller 31 and the turbine runner 32 of the torque converter 30.

[0031] The hydraulic circuit 45 uses the ATF hydraulic pressure supplied from a mechanical oil pump or an electric oil pump (not shown) as a base pressure, and adjusts the control hydraulic pressure of the automatic transmission 40 and the control hydraulic pressure of the lock-up clutch 34 according to control signals from the ECU 100. As a result, the automatic transmission 40 and the lock-up clutch 34 are controlled to states according to the control signals from the ECU 100.

[0032] The oil temperature sensor 46 detects the temperature of the ATF and outputs the detection result to the ECU 100. In addition to the oil temperature sensor 46, the vehicle 1 is provided with a plurality of sensors (none of which are shown) for detecting physical quantities necessary for controlling the vehicle 1, such as the accelerator opening, engine rotation speed, MG rotation speed, and vehicle speed. These sensors transmit their detection results to the ECU 100.

[0033] The ECU 100 includes a central processing unit (CPU) and an internal memory (not shown). The ECU 100 executes predetermined calculations based on information from each sensor and information stored in the memory, and controls each device of the vehicle 1 based on the calculation results.

[0034] The driving modes of the vehicle 1 include a motor driving mode and a hybrid driving mode.

[0035] In the motor running mode, the ECU 100 puts the automatic transmission 40 in a non-power transmitting state (neutral state) to disconnect the engine 10 from the rotary shaft 35, and rotates the rotary shaft 35 with the power of the MG 20 to run the vehicle 1.

[0036] During the hybrid driving mode, the ECU 100 connects the engine 10 to the rotary shaft 35 by putting the automatic transmission 40 into a power transmission state, and rotates the rotary shaft 35 using the power of at least one of the engine 10 and the MG 20 to drive the vehicle 1.

[0037] <Lock-up clutch engagement control> 2 is a flowchart showing an example of a processing procedure when the ECU 100 controls engagement of the lock-up clutch (LUC) 34. This flowchart is repeatedly executed every time a predetermined condition is satisfied (for example, at every predetermined interval).

[0038] First, the ECU 100 determines whether or not the lock-up running condition is satisfied (step S10). This determination is made to determine whether or not the running state of the vehicle 1 is a steady running state (e.g., a state in which the vehicle 1 is running at a high constant speed) that is suitable for running with the lock-up clutch 34 engaged. For example, the ECU 100 determines whether or not the vehicle 1 is running steadily based on the accelerator opening and the vehicle speed, and determines that the lock-up running condition is satisfied when the vehicle 1 is running steadily.

[0039] If the lockup driving condition is satisfied (YES in step S10), ECU 100 obtains the ATF temperature from oil temperature sensor 46 and determines whether the ATF temperature is higher than a predetermined LU (lockup) possible temperature (step S12). Considering that a low ATF temperature may cause abnormal noise or a deterioration in ride comfort when lockup clutch 34 is engaged due to high viscosity of the ATF, this determination is made to determine whether the ATF temperature is high enough to prevent such abnormal noise and deterioration in ride comfort.

[0040] If the ATF temperature is higher than the LU possible temperature (YES in step S12), ECU 100 brings lock-up clutch 34 into an engaged state (lock-up state) (step S14).

[0041] On the other hand, when the lock-up driving condition is not satisfied (NO in step S10), or even when the lock-up driving condition is satisfied but the ATF temperature is lower than the lock-up possible temperature (NO in step S12), the ECU 100 releases the lock-up clutch 34 (non-lock-up state) (step S16).

[0042] <ATF Temperature Rise Control> In the vehicle 1 configured as shown in FIG. 1, during the motor driving mode, the automatic transmission 40 is in a non-power transmission state (neutral state), and the automatic transmission 40 is not driven. Therefore, the warm-up frequency of the automatic transmission 40 is low, and accordingly, there is a concern that the state where the ATF does not rise in temperature and is less than the lock-up possible temperature continues, and the engagement frequency of the lock-up clutch 34 decreases.

[0043] Therefore, when the ATF temperature is less than the lock-up possible temperature, the ECU 100 according to the present embodiment executes "ATF temperature rise control" to raise the temperature of the ATF by increasing the output of the engine 10. By raising the ATF temperature higher than the lock-up possible temperature by executing the ATF temperature rise control, it is possible to increase the engagement frequency of the lock-up clutch 34 and improve the fuel efficiency.

[0044] However, since the ATF temperature rise control involves fuel consumption of the engine 10, depending on the driving state of the vehicle 1, even if the ATF temperature is raised higher than the lock-up possible temperature by the ATF temperature rise control, the lock-up clutch 34 may not be engaged, and conversely, the fuel efficiency may deteriorate.

[0045] Therefore, the ECU 100 determines whether or not to allow the execution of the ATF temperature rise control after determining whether or not an improvement in fuel efficiency can be expected by the ATF temperature rise control using the driving history of the vehicle 1 including the engagement history of the lock-up clutch 34 and the fuel consumption history of the engine 10.

[0046] 3 is a flowchart showing an example of a processing procedure when the ATF temperature increase control is performed by the ECU 100. This flowchart is started when the vehicle 1 starts a trip (when the control system of the vehicle 1 is started).

[0047] The ECU 100 uses the driving history of the vehicle 1, including the engagement history of the lock-up clutch 34 and the fuel consumption history of the engine 10, to calculate the percentage P1 of the LU (lock-up) disengagement period during one trip, the fuel consumption amount F1 during one trip, and the fuel consumption rate R1 during one trip (step S20).

[0048] Here, one trip refers to one driving period of the vehicle 1, and typically refers to the period from when the control system of the vehicle 1 is started to when it is next stopped. The LU off period is a period during which the vehicle 1 is in a steady driving state suitable for engaging the lock-up clutch 34, but the lock-up clutch 34 is released because the ATF temperature is below the LU possible temperature. The proportion P1 of the LU off period during one trip is the value obtained by dividing the LU off period during one trip by the duration of one trip.

[0049] The fuel consumption amount F1 during one trip is the fuel consumption amount (unit: g) of the engine 10 during one trip. The fuel consumption rate R1 during one trip is the value (unit: g / kWh) obtained by dividing the fuel consumption amount (unit: g) of the engine 10 during one trip by the driving power (unit: kWh) required during one trip.

[0050] In addition, the percentage P1 of the LU deviation period during one trip, the fuel consumption F1 during one trip, and the fuel consumption rate R1 during one trip may be, for example, the value of the most recent trip or the average value of the most recent multiple trips.

[0051] Next, the ECU 100 calculates the reduction amount ΔFd of fuel consumption of the engine 10 due to engagement of the lock-up clutch 34 during the LU off period in one trip, using the following formula (1) (step S22).

[0052] ΔFd = F1 × P1 × k … (1) In formula (1), "F1" is the fuel consumption (g) during one trip described above, and "P1" is the ratio of the LU off period during one trip described above. "k" is a value equivalent to the ratio of the transmission efficiency of the torque converter 30 when the lock-up clutch 34 is engaged to the transmission efficiency of the torque converter 30 when the lock-up clutch 34 is disengaged. Note that "k" can be a constant because it is roughly determined by the hardware specifications of the torque converter 30.

[0053] Next, the ECU 100 calculates an increase ΔFu in fuel consumption of the engine 10 due to the execution of the ATF temperature increase control, using the following formula (2) (step S24).

[0054] ΔFu = R1 × h … (2) In formula (2), "R1" is the fuel consumption rate (g / kWh) during one trip, and "h" is a value (kWh) equivalent to the amount of heat required for one ATF temperature increase control. Note that "h" is roughly determined by the hardware specifications of the automatic transmission 40, and can therefore be a constant value.

[0055] Next, the ECU 100 determines whether or not the magnitude (absolute value) of the fuel efficiency decrease amount ΔFd calculated in step S22 is greater than the magnitude (absolute value) of the fuel increase amount ΔFu calculated in step S24 (step S26).

[0056] If the magnitude of the fuel efficiency decrease amount ΔFd is smaller than the fuel increase amount ΔFu (NO in step S26), the ATF temperature increase control is not expected to improve fuel efficiency, so ECU 100 does not allow the ATF temperature increase control (step S82).

[0057] On the other hand, if the fuel efficiency decrease amount ΔFd is greater than the fuel increase amount ΔFu (YES in step S26), improvement in fuel efficiency is expected through the ATF temperature increase control, so ECU 100 allows the ATF temperature increase control (step S30).

[0058] When the ATF temperature increase control is permitted, the ECU 100 obtains the ATF temperature from the oil temperature sensor 46 (step S32), and determines whether the ATF temperature is lower than the LU possible temperature (step S34).

[0059] If the ATF temperature is lower than the LU possible temperature (YES in step S34), ECU 100 executes the ATF temperature increase control (step S36).

[0060] When the ECU 100 executes the ATF temperature increase control during the motor driving mode, the ECU 100 operates the engine 10 while maintaining the automatic transmission 40 in a non-power transmitting state, thereby rotating the torque converter 30. This makes it possible to increase the temperature of the ATF without transmitting the output of the engine 10 to the drive wheels 50.

[0061] When the ATF temperature increase control is executed during the motor driving mode and the vehicle 1 is decelerating, the automatic transmission 40 may be put into a power transmission state and rotated by the power transmitted from the drive wheels 50. In this way, during the motor driving mode, the automatic transmission 40 is rotated by the deceleration energy of the vehicle 1, instead of the output of the engine 10, thereby making it possible to increase the temperature of the ATF.

[0062] When the ECU 100 executes the ATF temperature increase control during the hybrid driving mode, it increases the output of the engine 10 to increase the rotation speed of the torque converter 30 and the automatic transmission 40, and causes the MG 20 to generate regenerative power equivalent to the increase in the output of the engine 10. This makes it possible to increase the temperature of the ATF using the output of the engine 10, while recovering a portion of the energy consumed to increase the temperature of the ATF as regenerative power.

[0063] After execution of step S36, the process returns to step S32, and the ATF temperature increase control is continued until the ATF temperature reaches or exceeds the LU possible temperature by the ATF temperature increase control. When the ATF temperature reaches or exceeds the LU possible temperature (NO in step S34), ECU 100 stops the ATF temperature increase control (step S38).

[0064] As described above, ECU 100 according to this embodiment determines whether or not to permit the execution of ATF temperature rise control involving fuel consumption, using the driving history of vehicle 1, including the engagement history of lockup clutch 34 and the fuel consumption history of engine 10. Therefore, it is possible to determine whether or not to permit the execution of ATF temperature rise control after determining whether or not an improvement in fuel economy can be expected by engaging lockup clutch 34 during a release period in which lockup clutch 34 was not engaged in the past. As a result, fuel economy can be appropriately improved by increasing the engagement frequency of lockup clutch 34 through ATF temperature rise control.

[0065] More specifically, the ECU 100 according to this embodiment uses the travel history of the vehicle 1 to calculate a reduction amount ΔFd of fuel consumption of the engine 10 due to engagement of the lock-up clutch 34 during an LU off period in one trip, and an increase amount ΔFu of fuel consumption of the engine 10 due to execution of the ATF temperature rise control. Then, the ECU 100 allows the execution of the ATF temperature rise control when the magnitude of the reduction amount ΔFd is greater than the magnitude of the increase amount ΔFu. Therefore, when it is expected that fuel economy will be improved by engaging the lock-up clutch 34 during a past LU off period, the execution of the ATF temperature rise control is allowed. Therefore, it is possible to more appropriately improve fuel economy.

[0066] Particularly, in this embodiment, the reference period for calculating the reduction amount ΔFd of fuel consumption is not simply the release period of the lockup clutch 34, but is limited to the "LU disengagement period" during which the vehicle 1 is in a steady running state suitable for engagement of the lockup clutch 34 but the lockup clutch 34 is released because the ATF temperature is below the LU possible temperature. This makes it possible to more appropriately determine whether or not improvement in fuel economy can be expected by executing the ATF temperature increase control.

[0067] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present disclosure is defined by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0068] 1 vehicle, 10 engine, 12, 42 output shaft, 20 motor generator, 22 battery, 30 torque converter, 31 pump impeller, 32 turbine runner, 33 stator, 34 lock-up clutch, 35 rotating shaft, 40 automatic transmission, 41 input shaft, 45 hydraulic circuit, 46 oil temperature sensor, 50 drive wheel, 100 ECU.

Claims

1. A vehicle in which a torque converter with a lock-up clutch, an automatic transmission, and a motor generator are provided in this order in a power transmission path from an engine to drive wheels, an oil temperature sensor for detecting the temperature of hydraulic oil used in the automatic transmission, the lock-up clutch, and the torque converter; a control device that executes a temperature increase control to increase the temperature of the hydraulic oil by increasing an output of the engine when the temperature of the hydraulic oil is lower than a predetermined temperature; The lock-up clutch is engaged when the temperature of the hydraulic oil is equal to or higher than the predetermined temperature, the control device determines whether or not to permit execution of the temperature rise control by using a driving history of the vehicle including an engagement history of the lock-up clutch and a fuel consumption history of the engine; The control device includes: Using the driving history, a reduction in fuel consumption of the engine due to engagement of the lock-up clutch during a release period in which the lock-up clutch is not engaged and an increase in fuel consumption of the engine due to execution of the temperature increase control are calculated; When the magnitude of the reduction in the amount of fuel consumption is greater than the magnitude of the increase in the amount of fuel consumption, the execution of the temperature increase control is permitted; The vehicle does not permit the execution of the temperature increase control when the magnitude of the reduction in the fuel consumption is smaller than the magnitude of the increase in the fuel consumption.

2. the lock-up clutch is engaged when the vehicle is in a predetermined running state and the temperature of the hydraulic oil is higher than the predetermined temperature, 2. The vehicle according to claim 1, wherein the release period is a period during which the lock-up clutch is released because the vehicle is in the predetermined running state but the temperature of the hydraulic oil is lower than the predetermined temperature.

3. the vehicle driving modes include a motor driving mode in which the automatic transmission is in a non-power transmitting state and the vehicle is driven by power of the motor generator; 3. The vehicle according to claim 1, wherein when the control device executes the temperature increase control during the motor driving mode, the control device rotates the torque converter by operating the engine while maintaining the automatic transmission in the non-power transmitting state.

4. 4. The vehicle according to claim 3, wherein when the control device executes the temperature increase control during the motor driving mode and when the vehicle is decelerating, the control device puts the automatic transmission into a power transmission state and rotates the automatic transmission with power transmitted from the drive wheels.

5. the driving modes of the vehicle include a hybrid driving mode in which the automatic transmission is in a power transmitting state and the vehicle is driven by power from at least one of the engine and the motor generator; The vehicle according to any one of claims 1 to 4, wherein when the control device executes the temperature rise control during the hybrid driving mode, the control device increases the rotation amount of the torque converter and the automatic transmission by increasing the output of the engine, and generates regenerative power in the motor generator equivalent to the increase in the output of the engine.

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