Vehicle control device

Abstract

To reduce an amount of water contained in a lubricant while continuing operation of an internal combustion engine.SOLUTION: A vehicle control device is for a vehicle 90, a control object, which comprises an internal combustion engine 10 and an automatic transmission 85 which can transmit and receive torque to and from the internal combustion engine 10. The vehicle control device executes processes to: calculate an amount of dilution water which is an amount of water contained in a lubricant of the internal combustion engine 10 during operation of the internal combustion engine 10 on the basis of an operation state thereof; and to control the automatic transmission 85 so as to make the torque per unit duration of the internal combustion engine 10 smaller when the amount of the dilution water is large than the torque when the same is small while allowing operation of the internal combustion engine 10 to be continued.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] This invention relates to a control device for a vehicle.

Background Art

[0002] Patent Document 1 discloses a vehicle having an internal combustion engine, a first motor generator that drives the internal combustion engine, and a second motor generator for traveling. The internal combustion engine has a crankcase that houses a crankshaft, an intake passage having a throttle valve, and a blow-by gas recovery passage. The recovery passage communicates the crankcase with a portion of the intake passage downstream of the throttle valve.

[0003] In the above internal combustion engine, a part of the water generated by the combustion of fuel mixes from the cylinder into the crankcase. And this water mixes into the lubricating oil accumulated at the bottom of the crankcase. Therefore, when the amount of water mixed in the lubricating oil increases, the control device of the vehicle stops the combustion of fuel in the internal combustion engine. And the control device rotates the crankshaft by the first motor generator with the throttle valve closed. Along with this, the inside of the recovery passage becomes negative pressure with respect to the atmospheric pressure. This negative pressure promotes the evaporation of the water mixed in the lubricating oil and refluxes the evaporated water to the intake passage.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] When stopping the internal combustion engine to reduce the water mixed in the lubricating oil as in the technology disclosed in Patent Document 1, there are the following problems. That is, in Patent Document 1, while the crankshaft is rotated by the first motor generator, the driving force required for the vehicle is covered only by the second motor generator. However, for example, when the state of charge of the battery is insufficient, there is a possibility that the driving force required for the vehicle cannot be covered only by the second motor generator.

Means for Solving the Problems

[0006] A vehicle control device for solving the above problems controls a vehicle having an internal combustion engine and a torque applying device capable of transmitting and receiving torque between the output shaft of the internal combustion engine. During operation of the internal combustion engine, based on the operating state of the internal combustion engine, a water amount calculation process for calculating the dilution water amount, which is the amount of water contained in the lubricating oil of the internal combustion engine, and when the dilution water amount is large, while continuing the operation of the internal combustion engine, a specific process for controlling the torque applying device so that the torque per unit period in the internal combustion engine becomes smaller than when the dilution water amount is small is executed.

[0007] In the above configuration, when the specific process is executed, as the torque of the internal combustion engine per unit period becomes smaller, the pressure in the cylinder decreases. Therefore, the gas leaking from the cylinder to the crankcase decreases. As a result, the water reaching the crankcase together with this gas and mixing into the lubricating oil decreases. On the other hand, if the internal combustion engine continues to operate, the temperature of the crankcase and thus the lubricating oil is in a considerably high state. Therefore, the amount of water evaporated from the lubricating oil hardly decreases. Thus, in the above configuration, since the amount of water evaporated is almost constant while the amount of water mixed in decreases, the dilution water amount can be decreased while continuing the operation of the internal combustion engine.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

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Figure 8

DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an embodiment of the vehicle control device will be described with reference to the drawings. <Overall Configuration of the Vehicle> As shown in FIG. 1, the vehicle 90 includes an internal combustion engine 10, a drive clutch 81, a motor generator 82, a transmission unit 80, a hydraulic mechanism 86, a differential 71, a plurality of drive wheels 72, an inverter 78, and a battery 79.

[0010] The internal combustion engine 10 is a drive source of the vehicle 90. Details of the internal combustion engine 10 will be described later. The internal combustion engine 10 has a crankshaft 14. The crankshaft 14 is an output shaft of the internal combustion engine 10.

[0011] The motor generator 82 is a drive source of the vehicle 90. The motor generator 82 has both functions of an electric motor and a generator. The motor generator 82 has a stator 82C, a rotor 82B, and a rotating shaft 82A. The rotor 82B is rotatable with respect to the stator 82C. The rotating shaft 82A rotates integrally with the rotor 82B. The motor generator 82 is electrically connected to the battery 79 via the inverter 78. The battery 79 supplies power to the motor generator 82 or receives power from the motor generator 82. The inverter 78 performs DC-AC conversion.

[0012] The drive clutch 81 is interposed between the internal combustion engine 10 and the motor generator 82. The drive clutch 81 assumes a connected state or a disconnected state according to the hydraulic pressure from the hydraulic mechanism 86. In the connected state, the drive clutch 81 connects the crankshaft 14 and the rotary shaft 82A of the motor generator 82. In the disconnected state, the drive clutch 81 disconnects the crankshaft 14 and the rotary shaft 82A of the motor generator 82. Although not shown, the hydraulic mechanism 86 includes a plurality of oil passages, a solenoid valve that switches the flow path of the hydraulic oil, and an electric pump that supplies the hydraulic oil to the oil passage, etc.

[0013] The transmission unit 80 has a torque converter 83 and an automatic transmission 85. The torque converter 83 has a pump impeller 83A, a turbine liner 83B, and a lock-up clutch 84. The torque converter 83 is a fluid coupling having a torque amplification function. The pump impeller 83A rotates integrally with the rotary shaft 82A of the motor generator 82. The turbine liner 83B rotates integrally with the input shaft 85A of the automatic transmission 85. The lock-up clutch 84 directly connects the pump impeller 83A and the turbine liner 83B according to the hydraulic pressure from the hydraulic mechanism 86.

[0014] The automatic transmission 85 is a stepped transmission capable of switching the gear ratio in multiple stages. The automatic transmission 85 has, in addition to the input shaft 85A, an output shaft 85B, a plurality of friction engagement elements 85C, and a plurality of planetary gear mechanisms 85D. In FIG. 1, the plurality of friction engagement elements 85C are represented as a single unit. The same applies to the plurality of planetary gear mechanisms 85D. The plurality of friction engagement elements 85C and the plurality of planetary gear mechanisms 85D are interposed between the input shaft 85A and the output shaft 85B. The plurality of friction engagement elements 85C are composed of a plurality of clutches and a plurality of brakes. That is, the friction engagement element 85C is either a clutch or a brake. Each friction engagement element 85C switches its engaged or disengaged state according to the hydraulic pressure from the hydraulic mechanism 86. And according to the engaged or disengaged state of each friction engagement element 85C, the automatic transmission 85 forms one of a plurality of preset shift stages. The plurality of shift stages are any one of the shift stages for forward travel, the shift stages for reverse travel, and the non-travel shift stages that cut off the power transmission between the input shaft 85A and the output shaft 85B. Further, in the shift stages for forward travel, there are a plurality of shift stages such as "1st speed" to "5th speed". A separate gear ratio is set for each shift stage for forward travel. The larger the shift stage, the smaller the gear ratio. The gear ratio is the value obtained by dividing the rotational speed of the input shaft 85A by the rotational speed of the output shaft 85B.

[0015] The output shaft 85B of the automatic transmission 85 is connected to the left and right drive wheels 72 via the differential 71. The differential 71 allows a difference in rotational speed to occur between the left and right drive wheels 72. The drive clutch 81, the motor generator 82, and the transmission unit 80 are housed in a single case. That is, the drive clutch 81, the motor generator 82, and the transmission unit 80 are configured as an integrated hybrid transaxle.

[0016] In the above series of power transmission systems, when the drive clutch 81 is in the connected state, the crankshaft 14 of the internal combustion engine 10 can apply torque to the motor generator 82, the torque converter 83, and the automatic transmission 85. Also, when the drive clutch 81 is in the connected state, the motor generator 82 can apply torque to the crankshaft 14. These motor generator 82, torque converter 83, and automatic transmission 85 are torque applying devices capable of transmitting torque to and from the crankshaft 14. Being capable of transmitting torque to and from the crankshaft 14 means that at least one of applying torque from the crankshaft 14 and applying torque to the crankshaft 14 is possible. Note that the motor generator 82 can also apply torque to the drive wheels 72 together with the crankshaft 14.

[0017] The vehicle 90 has a shift device 290 for switching the shift range Q of the automatic transmission 85. The shift device 290 has a shift lever operated by the occupant. When "D range" is selected by the shift lever, the automatic transmission 85 forms a gear stage for forward travel. When "R range" is selected by the shift lever, the automatic transmission 85 forms a gear stage for reverse travel. When "N range" or "P range" is selected by the shift lever, the automatic transmission 85 forms a gear stage for non-travel.

[0018] Vehicle 90 includes a shift sensor 56, a battery sensor 57, a vehicle speed sensor 58, an accelerator sensor 59, and a power switch 60. The shift sensor 56 detects the shift range Q selected by the shift device 290. The battery sensor 57 detects battery information B such as the current, voltage, and temperature of the battery 79. The vehicle speed sensor 58 detects the traveling speed of the vehicle 90 as the vehicle speed SP. The accelerator sensor 59 detects the depression amount of the accelerator pedal in the vehicle 90 as the accelerator operation amount ACC. Each of the above sensors repeatedly transmits a signal corresponding to the information it has detected to a control device 100 described later. The power switch 60 is a system startup switch for the vehicle 90. The power switch 60 transmits a signal U corresponding to the driver's operation to the control device 100 described later.

[0019] <Schematic Configuration of Internal Combustion Engine> As shown in FIG. 2, the internal combustion engine 10 includes a cylinder block 26, an oil pan 27, and a crankcase 28. The internal combustion engine 10 also includes a plurality of cylinders 11, a plurality of pistons 12, a plurality of connecting rods 13, and the crankshaft 14. The number of cylinders 11 is four. In FIG. 2, only one of the plurality of cylinders 11 is shown. The same applies to the pistons 12 and the connecting rods 13. The pistons 12 and the connecting rods 13 are provided for each cylinder 11.

[0020] The cylinder 11 is a space partitioned in the cylinder block 26. The cylinder 11 is a space where the mixture of fuel and intake air burns. The piston 12 is located in the cylinder 11. The piston 12 reciprocates. The piston 12 is connected to the crankshaft 14 via the connecting rod 13. The crankshaft 14 rotates according to the reciprocation of the piston 12. The crankshaft 14 is located in the crank chamber 28. The crank chamber 28 is a space partitioned by the lower part in the cylinder block 26 and the oil pan 27. The lower part in the cylinder block 26 may also be referred to as the crankcase. The crank chamber 28 communicates with each cylinder 11. The oil pan 27 is box-shaped. Lubricating oil for lubricating various parts of the internal combustion engine 10 accumulates at the bottom of the oil pan 27.

[0021] The internal combustion engine 10 has a water jacket 25. In FIG. 2, for the sake of convenience, the water jacket 25 is shown by a thick solid line. The water jacket 25 is a passage partitioned in the cylinder block 26 through which cooling water flows. The water jacket 25 is located around a plurality of cylinders 11.

[0022] The internal combustion engine 10 has a plurality of spark plugs 19. In FIG. 2, only one of the plurality of spark plugs 19 is shown. The spark plug 19 is provided for each cylinder 11. The spark plug 19 ignites the mixture of intake air and fuel in the cylinder 11.

[0023] The internal combustion engine 10 has a plurality of fuel injection valves 17. In FIG. 2, only one of the plurality of fuel injection valves 17 is shown. The fuel injection valve 17 is provided for each cylinder 11. The fuel injection valve 17 directly supplies fuel to the cylinder 11 without passing through the intake passage 15 described later. The fuel injection valve 17 injects hydrogen as fuel.

[0024] The internal combustion engine 10 has an intake passage 15, a throttle valve 16, and an exhaust passage 21. The intake passage 15 is connected to each cylinder 11. In the intake passage 15, intake air from the outside flows. The throttle valve 16 is located in the middle of the intake passage 15. The throttle valve 16 adjusts the amount of intake air (hereinafter referred to as the intake air amount) GA. The exhaust passage 21 is connected to each cylinder 11. In the exhaust passage 21, exhaust from each cylinder 11 flows.

[0025] The internal combustion engine 10 has a blow-by gas recirculation mechanism. The blow-by gas recirculation mechanism is a mechanism for recirculating blow-by gas, which is gas that leaks into the crankcase 28 through the gap between the wall surface partitioning the cylinder 11 in the cylinder block 26 and the piston 12, into the intake passage 15. The blow-by gas recirculation mechanism has a first blow-by gas passage 31, a second blow-by gas passage 32, and a PCV valve 33. The first blow-by gas passage 31 communicates the crankcase 28 with the upstream portion of the intake passage 15 with respect to the throttle valve 16. The second blow-by gas passage 32 communicates the crankcase 28 with the downstream portion of the intake passage 15 with respect to the throttle valve 16. The PCV valve 33 is located in the middle of the second blow-by gas passage 32. The PCV valve 33 opens when the pressure in the downstream portion of the intake passage 15 with respect to the throttle valve 16 becomes lower than a specified value during operation of the internal combustion engine 10. At this time, the second blow-by gas passage 32 allows blow-by gas to flow from the crankcase 28 to the intake passage 15. When the blow-by gas flows through the second blow-by gas passage 32, intake air flows from the intake passage 15 to the crankcase 28 in the first blow-by gas passage 31.

[0026] The internal combustion engine 10 has a crank position sensor 40, an air flow meter 41, a water temperature sensor 44, and an oil temperature sensor 45. The crank position sensor 40 detects the rotational position CR of the crankshaft 14. The air flow meter 41 detects the intake air amount GA. The water temperature sensor 44 detects the temperature (hereinafter referred to as the cooling water temperature) W of the cooling water at the outlet of the water jacket 25. The oil temperature sensor 45 detects the temperature L of the lubricating oil accumulated in the oil pan 27. Each of these sensors repeatedly transmits a signal corresponding to the information it has detected to a control device 100 described later.

[0027] <Schematic Configuration of Control Device> As shown in FIG. 1, the vehicle 90 has a control device 100. The control device 100 can be configured as one or more processors that execute various processes according to a computer program (software). Note that the control device 100 may be configured as a circuit (circuitry) including one or more dedicated hardware circuits such as an application specific integrated circuit (ASIC) that executes at least some of the various processes, or a combination thereof. The processor includes a CPU 111 and memories such as a RAM and a ROM 112. The memory stores program codes or instructions configured to cause the CPU 111 to execute processes. The memory, that is, the computer-readable medium, includes any available medium accessible by a general-purpose or dedicated computer. The control device 100 has a real-time clock which is a circuit that generates date and time information. Further, the control device 100 has an electrically rewritable non-volatile memory 113. The control device 100 performs various processes described below by the CPU 111 executing the program stored in the ROM 112.

[0028] The control device 100 receives the signal U from the power switch 60. When the control device 100 receives the signal U corresponding to the power switch 60 being turned on, it electrically connects the battery 79 and the motor generator 82. By doing so, the control device 100 puts the vehicle 90 in a drivable state. Hereinafter, the period from when the power switch 60 is turned on until it is turned off next is referred to as "one trip".

[0029] During one trip, the control device 100 repeatedly receives detection signals from various sensors attached to the vehicle 90. Specifically, the control device 100 receives detection signals regarding the following respective parameters.

[0030] · The rotational position CR of the crankshaft 14 detected by the crank position sensor 40 · The intake air amount GA detected by the air flow meter 41 · The coolant water temperature W detected by the water temperature sensor 44 · The temperature L of the lubricating oil detected by the oil temperature sensor 45 · The shift range Q detected by the shift sensor 56 · The battery information B detected by the battery sensor 57 · The vehicle speed SP detected by the vehicle speed sensor 58 · The accelerator operation amount ACC detected by the accelerator sensor 59 Based on the detection signals received from various sensors, the control device 100 calculates the following parameters at any time. The control device 100 calculates the engine rotation speed NE, which is the rotation speed of the crankshaft 14, based on the rotation position CR of the crankshaft 14. Further, the control device 100 calculates the engine load factor KL based on the engine rotation speed NE and the intake air amount GA. The engine load factor KL is a parameter that determines the amount of air filled in the cylinder 11. Specifically, the engine load factor KL is a value obtained by dividing the amount of air flowing into one cylinder 11 per combustion cycle by the reference air amount. The reference air amount changes according to the engine rotation speed NE. One combustion cycle is a series of periods during which one cylinder 11 experiences an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke once each. The control device 100 calculates the state of charge SOC of the battery 79 based on the battery information B. The state of charge SOC of the battery 79 is a value obtained by dividing the remaining capacity of the battery 79 by the full charge capacity of the battery 79. The full charge capacity of the battery 79 can be calculated based on, for example, the voltage and temperature of the battery 79. The remaining capacity of the battery 79 can be calculated based on, for example, the voltage and current of the battery 79.

[0031] <Regarding the control of the internal combustion engine> The control device 100 controls the internal combustion engine 10. To control the torque of the internal combustion engine 10 (hereinafter referred to as the engine torque) TE and the engine rotation speed NE, the control device 100 operates various devices to be operated, such as the throttle valve 16, the fuel injection valve 17, and the ignition plug 19. By doing so, the control device 100 adjusts the intake air amount GA, the injected fuel amount, the ignition timing, etc. And it is made possible to obtain the required engine torque TE and engine rotation speed NE.

[0032] <Regarding the control of the motor generator> The control device 100 controls the motor generator 82. The control device 100 operates the inverter 78 to control the torque and rotational speed of the motor generator 82. By doing so, the control device 100 causes the motor generator 82 to perform power running or regenerative running, and obtains the required torque and rotational speed of the motor generator 82.

[0033] In controlling the motor generator 82, the control device 100 takes into account the state of charge SOC of the battery 79. For example, during running in the hybrid mode described later, if the state of charge SOC of the battery 79 is lower than a predetermined target state of charge V, the control device 100 causes the motor generator 82 to perform regenerative running to generate electricity in the battery 79. On the other hand, if the state of charge SOC of the battery 79 is higher than the target state of charge V, the control device 100 causes the motor generator 82 to perform power running to discharge the battery 79. For example, the greater the absolute value of the difference between the state of charge SOC of the battery 79 and the target state of charge V, the greater the amount of charge or discharge per unit time. As a result of such control, the state of charge SOC of the battery 79 will be maintained at a value near the target state of charge V while fluctuating up and down across the target state of charge V.

[0034] The control device 100 can use two set values as the above-mentioned target charge rate V. One set value, the first set value V1, is predetermined as the charge rate SOC of the battery 79 to be ensured during normal driving. The other set value, the second set value V2, is a value larger than the first set value V1. Here, driving the vehicle 90 only by the power of the battery 79 without requiring the power of the internal combustion engine 10 is called electric driving. That is, in electric driving, the vehicle 90 is driven only by the torque of the motor generator 82 among the internal combustion engine 10 and the motor generator 82. The above-mentioned second set value V2 is determined as the minimum value of the charge rate SOC of the battery 79 required to drive the vehicle 90 a predetermined specified distance by electric driving. The specified distance is determined as a distance slightly longer than the maximum driving distance during the period when it is expected that the electric driving process will continue in the coping process described later. The first set value V1, the second set value V2, and the specified distance are predetermined by, for example, experiments or simulations. The control device 100 switches the target charge rate V between the first set value V1 and the second set value V2 through the setting process described later.

[0035] Note that the control device 100 may also use the resistance of the motor generator 82 generated by the power generation of the motor generator 82 as a brake. The brake due to the resistance of the motor generator 82 accompanying such power generation is called a regenerative brake. The control device 100 uses such a regenerative brake when the vehicle 90 is decelerating or the like.

[0036] <Regarding the control of the automatic transmission> The control device 100 targets the automatic transmission 85 for control. In order to control the gear ratio of the automatic transmission 85, the control device 100 operates a solenoid valve or the like of the hydraulic mechanism 86. By doing so, the control device 100 switches the connection / disconnection state of the friction engagement element 85C. That is, the control device 100 switches the gear stage and thus the gear ratio of the automatic transmission 85.

[0037] The control device 100 stores a plurality of shift maps in advance as information for switching the gear stage of the automatic transmission 85. The shift map defines the target gear stage, which is the optimal gear stage in the current driving situation. The basic characteristics of the plurality of shift maps are the same. Hereinafter, the characteristics will be described. As shown in FIG. 3, in the shift map, a plurality of shift lines for switching the target gear stage are set in the orthogonal coordinates with the vehicle speed SP on the X-axis and the accelerator operation amount ACC on the Y-axis. Note that FIG. 3 shows only some of the plurality of shift lines. Hereinafter, the characteristics of the shift lines in the shift map will be described with respect to the shift line indicated by the solid line in FIG. 3. Focusing on a specific accelerator operation amount ACC1, the plurality of shift lines are arranged such that a higher gear stage is selected as the vehicle speed SP increases. Also, focusing on a specific vehicle speed SP2, the plurality of shift lines are arranged such that a lower gear stage is selected as the accelerator operation amount ACC increases. When the vehicle speed SP changes so as to cross the shift line from the lower side to the higher side of the vehicle speed SP as viewed from a specific shift line, a determination of upshift is made. For example, when the shift line for switching between "2nd gear" and "3rd gear" is defined as the specific shift line A1, a determination of upshift is made when the vehicle speed SP increases from the first vehicle speed SP1 to the second vehicle speed SP2 across the specific shift line A1. Also, when the accelerator operation amount ACC changes so as to cross the shift line from the higher side to the lower side of the accelerator operation amount ACC as viewed from a specific shift line, a determination of upshift is made. On the other hand, when the vehicle speed SP changes so as to cross the shift line from the higher side to the lower side of the vehicle speed SP as viewed from a specific shift line, a determination of downshift is made. Also, when the accelerator operation amount ACC changes so as to cross the shift line from the lower side to the higher side of the accelerator operation amount ACC as viewed from a specific shift line, a determination of downshift is made. When a determination of upshift or downshift is made, the control device 100 changes the target gear stage. Note that although upshift and downshift are described using the same map in FIG. 3, in actuality, a shift map for upshift and a shift map for downshift are prepared separately. This applies to each of the plurality of types of maps described below.However, since the basic characteristics of the shift map for upshifting and the shift map for downshifting are common, their individual explanations are omitted.

[0038] The shift maps stored in the control device 100 include a normal map, a low-load map, and a high-load map. Among these maps, first, the difference between the normal map and the low-load map will be explained. In FIG. 3, the normal map is shown by a solid line, and the low-load map is shown by a two-dot chain line. There are the following differences for all shift lines between the normal map and the low-load map. That is, focusing on a specific accelerator operation amount ACC1, the shift line of the low-load map shown by the two-dot chain line is shifted to the higher vehicle speed SP side when viewed from the shift line of the normal map shown by the solid line. Due to such differences, different shift stages can be selected between the case of using the normal map and the case of using the low-load map even in the same driving situation. This point will be described in detail using the above-mentioned specific shift line A1 for switching between "second gear" and "third gear" as an example. For example, consider a first driving situation where the vehicle speed SP increases from the first vehicle speed SP1 to the second vehicle speed SP2 across the specific shift line A1 of the normal map when the accelerator operation amount ACC is the first operation amount ACC1. Note that the second vehicle speed SP2 is a value lower than the vehicle speed SP on the specific shift line A2 of the low-load map. In the first driving situation, if the normal map is used, the target shift stage upshifts from "second gear" to "third gear". On the other hand, when the low-load map is used, the shift stage remains "second gear". Thus, in the low-load map, a smaller shift stage can be selected for the same vehicle speed SP and the same accelerator operation amount ACC compared to the normal map. In other words, the low-load map is more likely to select a larger gear ratio compared to the normal map.

[0039] Next, the differences between the normal map and the high-load map will be explained. As shown in FIG. 4, the high-load map has characteristics opposite to those of the low-load map. That is, focusing on a specific accelerator operation amount ACC, the shift line of the high-load map indicated by the two-dot chain line is shifted to the side with a lower vehicle speed SP when viewed from the shift line of the normal map indicated by the solid line. Therefore, when the high-load map is used, a higher gear can be selected for the same vehicle speed SP and the same accelerator operation amount ACC compared to when the normal map is used. In other words, the high-load map makes it easier to select a smaller gear ratio compared to the normal map.

[0040] <Regarding the driving mode of the vehicle> The control device 100 switches the driving mode of the vehicle 90 to the hybrid mode or the electric mode according to the situation. In the electric mode, the control device 100 stops the internal combustion engine 10 while driving the motor generator 82. Then, the control device 100 uses only the motor generator 82 as the driving source of the vehicle 90. Note that the electric mode includes a normal electric mode in which the drive clutch 81 is in the disengaged state and a motor ring mode in which the drive clutch 81 is in the engaged state. The motor ring mode is dedicated to the countermeasure process described later. On the other hand, in the hybrid mode, the control device 100 drives both the internal combustion engine 10 and the motor generator 82 and engages the drive clutch 81. Then, the control device 100 uses both the internal combustion engine 10 and the motor generator 82 as the driving source of the vehicle 90. Note that in the hybrid mode, the control device 100 may also generate electricity in the motor generator 82 by the power of the internal combustion engine 10.

[0041] During a single trip, the control device 100 repeatedly calculates a required driving force, which is the force required as the driving force of the vehicle 90, based on the vehicle speed SP and the accelerator operation amount ACC. Then, based on this required driving force and the latest state of charge SOC of the battery 79, the driving mode of the vehicle 90 is selected. Basically, the control device 100 selects the electric mode when the required driving force is small and the hybrid mode when the required driving force is large. Examples of cases where the required driving force is small include when the vehicle 90 starts and when driving under light load with low forward acceleration. However, when the state of charge SOC of the battery 79 is low, the control device 100 selects the hybrid mode even if the required driving force is small.

[0042] When the control device 100 selects the electric mode, it controls the motor generator 82 so as to obtain the required driving force. The details of the control in the hybrid mode will be described later. <Details of Control in Hybrid Mode> The details of how the internal combustion engine 10, the motor generator 82, and the automatic transmission 85 are controlled when the control device 100 selects the hybrid mode will be described. Here, as processes for performing control in the hybrid mode, there are three types: normal process, specific process, and increase process. The basic contents of these three types of processes are common. Below, the common contents will be described, and then the differences between the processes will be described.

[0043] In each process, the control device 100 determines a target gear stage corresponding to the latest vehicle speed SP and the accelerator operation amount ACC based on any one of a plurality of shift maps. Then, the control device 100 controls the automatic transmission 85 so that the actual gear stage of the automatic transmission 85 matches the target gear stage. Further, the control device 100 calculates a target value of the engine rotational speed NE (hereinafter referred to as the target engine rotational speed), a target value of the engine torque TE (hereinafter referred to as the target engine torque), and a target value of the torque of the motor generator 82 (hereinafter referred to as the target motor torque) based on the latest required driving force and the like. Then, the control device 100 controls the internal combustion engine 10 so that the actual engine torque TE matches the target engine torque and the actual engine rotational speed NE matches the target engine rotational speed. Further, the control device 100 controls the motor generator 82 so that the actual torque of the motor generator 82 matches the target motor torque. The control device 100 repeats the calculation of each target value and the control of the automatic transmission 85, the internal combustion engine 10, and the motor generator 82 based on the target values. Although detailed explanations are omitted, the target engine torque and the target motor torque are values per unit period. The unit period is, for example, one combustion cycle of the internal combustion engine 10.

[0044] The control device 100 calculates the target engine rotational speed, the target engine torque, and the target motor torque as follows. First, the control device 100 calculates a target value of the system output (hereinafter referred to as the target system output), which is the total output required for the running of the vehicle 90, based on the latest required driving force and the like. The system output is a parameter defined as the product of the shaft torque JT and the engine rotational speed NE. The shaft torque JT indicates the sum of the engine torque TE and the torque of the motor generator 82. Incidentally, the engine rotational speed NE is the same as the rotational speed of the motor generator 82. When the control device 100 calculates the target system output, it calculates a combination of the shaft torque JT and the engine rotational speed NE corresponding to this target system output and the latest target gear position. At this time, the control device 100 refers to, for example, the power map shown in FIG. 5. As shown in FIG. 5, the power map shows the operation line D for each gear position in the orthogonal coordinates with the engine rotational speed NE as the X-axis and the shaft torque JT as the Y-axis. The operation line D represents the relationship between the engine rotational speed NE and the shaft torque JT at each gear position. The operation line D for each gear position has the following characteristics. That is, at each gear position, the higher the engine rotational speed NE, the larger the shaft torque JT. Focusing on a certain specific engine rotational speed NE1, the larger the gear position, the larger the shaft torque JT. Also, focusing on a certain specific shaft torque JT1, the smaller the gear position, the higher the engine rotational speed NE. In addition, the power map shows an equal output line F defined by the product of the engine rotational speed NE and the shaft torque JT. As shown by the dashed-dotted line in FIG. 5, the equal output line F is an inverse proportional curve. Focusing on a certain specific system output, at a smaller gear position, compared to a larger gear position, the engine rotational speed NE is higher and the shaft torque JT is smaller. Based on such a power map, the control device 100 calculates a combination of the shaft torque JT and the engine rotational speed NE corresponding to the target system output and the target gear position. In calculating this combination, first, the control device 100 specifies the equal output line F corresponding to the target system output. Also, the control device 100 specifies the operation line D corresponding to the target gear position. Then, the control device 100 sets the engine rotational speed NE1, which is the intersection H of the specified equal output line F and the operation line D, as the target engine rotational speed.Further, the control device 100 sets the shaft torque JT1 at the intersection H as the target value of the shaft torque JT (hereinafter referred to as the target shaft torque). In FIG. 5, the intersection H is shown by taking the case where the target gear stage is "5th gear" as an example. When the control device 100 calculates the target shaft torque, it distributes this target shaft torque to the internal combustion engine 10 and the motor generator 82. At this time, the control device 100 takes into account the state of charge SOC of the battery 79. That is, when there is a charging requirement for the battery 79, the control device 100 sets the target motor torque to a negative value so as to cause the motor generator 82 to perform regenerative operation. On the other hand, when there is a discharging requirement for the battery 79, the control device 100 sets the target motor torque to a positive value so as to cause the motor generator 82 to perform power running operation. When the control device 100 calculates the target motor torque, it sets the value obtained by subtracting the target motor torque from the target shaft torque as the target engine torque. Note that the control device 100 always sets the target motor torque to the same value if the state of charge SOC of the battery 79 is the same. The control device 100 calculates each target value as described above.

[0045] Now, in the normal process, the specific process, and the increase process, the shift maps used for controlling the automatic transmission 85 are different. The control device 100 uses the normal map in the normal process. The control device 100 uses the low-load map in the specific process. The control device 100 uses the high-load map in the increase process. Here, in the low-load map used in the specific process, a lower gear is set under the same vehicle speed SP and the same accelerator operation amount ACC compared to the normal map used in the normal process. That is, in the specific process, a lower gear is set compared to the normal process for the same required driving force and thus the target system output. As described above, when setting a lower gear for the same target system output, the target engine speed becomes higher and the target shaft torque becomes smaller compared to when setting a higher gear. Here, if the state of charge SOC of the battery 79 is the same, the target motor torque is the same. That is, in the specific process, when the specific process is executed, the target engine speed becomes higher and the target engine torque becomes smaller compared to when the normal process is performed under the same conditions where the values of each specified parameter are the same. The specified parameters are the vehicle speed SP, the accelerator operation amount ACC, and the state of charge SOC of the battery 79, and thus the required driving force, the target system output, and the target motor torque determined therefrom. Thus, the control device 100 controls the automatic transmission 85 so that in the specific process, the engine speed NE becomes higher and the engine torque TE per unit period becomes smaller compared to when the normal process is performed under the same conditions where the values of each specified parameter are the same. Conversely, in the increase process using the high-load map, a higher target gear is set compared to the normal process using the normal map. That is, in the increase process, the automatic transmission 85 is controlled so that the engine speed NE becomes lower and the engine torque TE per unit period becomes larger compared to when the normal process is performed under the same conditions where the values of each specified parameter are the same when the increase process is performed. Hereinafter, the condition where the values of each specified parameter are the same will be simply referred to as the same conditions.

[0046] Among the above-described normal process, specific process, and increase process, the specific process and the increase process are dedicated to the countermeasure process described later. That is, when the control device 100 runs the vehicle 90 in the hybrid mode during one trip, basically, the normal process is selected among these normal process, specific process, and increase process. And the control device 100 selects the specific process or the increase process only when the dilution water amount P, which is the amount of water mixed in the lubricating oil, is equal to or more than the determination value PA in relation to the countermeasure process to be described in detail later. In other words, the control device 100 performs the normal process when the dilution water amount P is less than the determination value PA, and performs the specific process or the increase process when the dilution water amount P is equal to or more than the determination value PA. Note that the control device 100 turns on the normal process flag during the execution of the normal process, and turns off the normal process flag during the non-execution of the normal process.

[0047] <Water amount calculation process> The dilution water amount P will be described in detail. Specifically, the dilution water amount P is the amount of water contained per unit volume of the lubricating oil. In the internal combustion engine 10, the blow-by gas leaking from the cylinder 11 to the crank chamber 28 contains moisture accompanying the combustion of the air-fuel mixture. This moisture may liquefy and mix into the lubricating oil. If the situation where water mixes into the lubricating oil continues, the dilution water amount P, which is the amount of water contained in the lubricating oil, will increase. At the same time, the dilution of the lubricating oil by water progresses. On the other hand, when the temperature L of the lubricating oil rises, the water mixed in the lubricating oil vaporizes. At the same time, the dilution water amount P decreases. The vaporized moisture flows into the intake passage 15 through the second blow-by gas passage 32 when the PCV valve 33 is opened according to the operating state of the internal combustion engine 10. The control device 100 is capable of executing a water amount calculation process for calculating the dilution water amount P that increases and decreases in this way.

[0048] The control device 100 repeats the water quantity calculation process during one trip. The control device 100 calculates the dilution water quantity P once for each water quantity calculation process. When calculating the dilution water quantity P, the control device 100 first calculates the new mixing-in quantity P1 and the evaporation water quantity P2. The new mixing-in quantity P1 is the amount of water newly mixed into the lubricating oil from the time when the water quantity calculation process was last executed until the next time the water quantity calculation process is executed. The evaporation water quantity P2 is the amount of water evaporated from the lubricating oil from the time when the water quantity calculation process was last executed until the next time the water quantity calculation process is executed. When the control device 100 calculates the new mixing-in quantity P1 and the evaporation water quantity P2, it calculates the value obtained by subtracting the evaporation water quantity P2 from the new mixing-in quantity P1 as the update value. Then, the control device 100 adds this update value to the previous value of the dilution water quantity P stored in the non-volatile memory 113. The control device 100 calculates the obtained value as the latest dilution water quantity P. When the control device 100 calculates the latest dilution water quantity P, it stores that value in the non-volatile memory 113. Note that the control device 100 stores the dilution water quantity P over time while overwriting old data with new data for a certain period. The control device 100 treats the latest value among the time-series data of this dilution water quantity P as the above-mentioned previous value. Note that the execution interval of the water quantity calculation process is, for example, several seconds.

[0049] The control device 100 stores a new map in advance as information for calculating the new mixing amount P1. The new map represents the relationship among the engine speed NE, the engine load factor KL, and the added water amount. The added water amount is the amount of water newly mixed into the lubricating oil per unit time when the engine speed NE is a specific value and the engine load factor KL is a specific value. This unit time is the same as the execution interval of the water amount calculation process. Basically, the relationship among the engine speed NE, the engine load factor KL, and the added water amount in the new map is as follows. That is, when the engine speed NE is the same, the higher the engine load factor KL, the larger the added water amount. Here, when the engine load factor KL is high, the fuel injection amount increases. Therefore, the amount of water generated with the combustion of the air-fuel mixture increases. In addition to this, when the engine load factor KL is high, the pressure in the cylinder 11 increases. Accordingly, the amount of gas leaking from the cylinder 11 into the crank chamber 28 increases. These factors combined can result in an increase in the amount of water mixed into the crank chamber 28 when the engine load factor KL is high. The new map reflects such causal relationships. The new map is created based on, for example, experiments or simulations. When calculating the new mixing amount P1, the control device 100 calculates the added water amount corresponding to the current engine speed NE and engine load factor KL in the new map as the current new mixing amount P1.

[0050] The control device 100 stores an evaporation map in advance as information for calculating the evaporation water amount P2. The evaporation map represents the relationship between the temperature L of the lubricating oil and the subtracted water amount. The subtracted water amount is the amount of water evaporated from the lubricating oil per unit time when the temperature L of the lubricating oil is a specific value. The unit time is the same as that of the new map, which is the same as the execution interval of the water amount calculation process. In the evaporation map, basically, the higher the temperature L of the lubricating oil, the larger the subtracted water amount. The evaporation map is created based on, for example, experiments or simulations. When calculating the evaporation water amount P2, the control device 100 calculates the subtracted water amount corresponding to the current temperature L of the lubricating oil in the evaporation map as the current evaporation water amount P2.

[0051] Here, the engine speed NE and the engine load factor KL that define the additional water amount in the new map are parameters representing the operating state of the internal combustion engine 10. Also, the temperature L of the lubricating oil that defines the subtracted water amount in the evaporation map is a parameter representing the operating state of the internal combustion engine 10. The control device 100 utilizes these new map and evaporation map when calculating the dilution water amount P. That is, the control device 100 calculates the dilution water amount P based on the operating state of the internal combustion engine 10.

[0052] As described above, the control device 100 repeats the water volume calculation process during one trip. During this one trip, there are times when the vehicle 90 is in hybrid mode and times when it is in electric mode. During the period when the vehicle 90 is in electric mode, the internal combustion engine 10 stops. During the stop of this internal combustion engine 10, the combustion of fuel in the internal combustion engine 10 is stopped. When the combustion of fuel in the internal combustion engine 10 is stopped, the water newly generated along with the combustion of fuel disappears. Therefore, the water newly mixed into the lubricating oil is substantially eliminated. On the other hand, if the warm-up of the internal combustion engine 10 is completed after the start of one trip, basically the temperature L of the lubricating oil is relatively high. When the temperature L of the lubricating oil becomes high, the water mixed in the lubricating oil evaporates. Therefore, during running in electric mode, the dilution water volume P decreases as water evaporates from the lubricating oil without new water mixing into the lubricating oil. The water evaporated from the lubricating oil flows into the intake passage 15 through the second blow-by gas passage 32 when the internal combustion engine 10 restarts. In consideration of the decrease in the dilution water volume P in such a process, in the present embodiment, the water volume calculation process is continued during one trip including the period when the vehicle 90 is in electric mode. On the other hand, when one trip ends, the control device 100 ends the water volume calculation process at that time. Here, the temperature L of the lubricating oil is high at the end of one trip, and water may evaporate from the lubricating oil after the end of one trip. However, the soak period from the end of one trip to the start of the next trip is often relatively long. During this soak period, the PCV valve 33 is closed. Therefore, the water evaporated from the lubricating oil during the soak period does not return to the intake passage 15. And this water re-mixes into the lubricating oil as the engine temperature including the lubricating oil decreases during the soak period. From such a viewpoint, the water volume calculation process is suspended during the soak period. Note that when the soak period is short, the control device 100 considers the amount of water evaporated during the soak period when starting the water volume calculation process in the next trip. That is, when the soak period is shorter than the specified soak period, the control device 100 calculates the amount of water evaporated during the soak period based on the evaporation map when executing the water volume calculation process for the first time in one trip.Then, the control device 100 calculates the latest dilution water amount P by adding the value obtained by subtracting this water amount from the previous value of the dilution water amount P stored in the non-volatile memory 113 and the above update value. The control device 100 stores a prescribed soak period in advance. The prescribed soak period is, for example, determined in advance by experiment or simulation as the length of time from the timing when the combustion of fuel in the internal combustion engine 10 stops until the evaporated water starts to re-mix into the lubricating oil.

[0053] <Setting process> The control device 100 repeats a setting process for setting the target charge rate V of the battery 79 during one trip. In the setting process, the control device 100 switches the target charge rate V between a first set value V1 and a second set value V2 in relation to the above dilution water amount P. Hereinafter, the specific processing procedure of the setting process will be described.

[0054] As shown in FIG. 6, when the control device 100 starts the setting process, it first performs the process of step S110. In step S110, the control device 100 calculates a predicted water volume PY. The predicted water volume PY is a predicted value of the dilution water volume P after a predetermined period from the current time. The predetermined period is, for example, 10 minutes. The control device 100 stores the predetermined period in advance. The predetermined period is the length of time that is expected to be able to achieve the following matters with a certain margin when the vehicle 90 continues to run. The above matters are to increase the charging rate SOC of the battery 79 from the first set value V1 to the second set value V2. The predetermined period is, for example, determined in advance by experiments or simulations. When calculating the predicted water volume PY, the control device 100 calculates a water volume change rate, which is the change amount of the dilution water volume P per unit time. Specifically, the control device 100 refers to the latest dilution water volume P and the dilution water volume P calculated one time before among the time-series data of the dilution water volume P. Then, the control device 100 divides the value obtained by subtracting the dilution water volume P calculated one time before from the latest dilution water volume P by the execution interval of the water volume calculation process. The control device 100 treats the obtained value as the water volume change rate. After that, the control device 100 calculates the product of the water volume change rate and the predetermined period as the predicted water volume PY. Note that the predetermined period is converted into the same unit as the unit time of the water volume change rate. When the control device 100 calculates the predicted water volume PY, it advances the process to step S120.

[0055] In step S120, it is determined whether the predicted water volume PY is equal to or greater than a determination value PA. The control device 100 stores the determination value PA in advance. Here, when the dilution of the lubricating oil progresses, the lubricating function of the lubricating oil deteriorates. The determination value PA is determined in advance by experiments or simulations, for example, as a value at which it can be considered that measures to reduce the dilution water volume P are necessary to avoid such a deterioration of the function. When the predicted water volume PY calculated in step S110 is less than the determination value PA (step S120: NO), the control device 100 advances the process to step S130. In this case, the control device 100 sets the first set value V1 as the target charging rate V. Note that when the control device 100 sets the first set value V1 as the target charging rate V when the process advances to step S130, it maintains that state.

[0056] On the other hand, in step S120, when the predicted water volume PY is equal to or greater than the determination value PA (step S120: YES), the control device 100 proceeds with the process to step S140. In this case, the control device 100 sets the second set value V2 as the target charge rate V. Note that when the control device 100 sets the second set value V2 as the target charge rate V when the process proceeds to step S140, it maintains that state.

[0057] When the control device 100 executes the process of step S130 or step S140, it temporarily ends the series of processes of the setting process. After that, the control device 100 executes the process of step S110 again. The control device 100 repeats the above setting process during one trip.

[0058] <Overview of the countermeasure process> As described above, during traveling in the hybrid mode, the control device 100 basically performs normal processing. That is, after the start of one trip, when the control device 100 first enters a situation of traveling in the hybrid mode, it selects normal processing. After that, as long as the situation is not such that the dilution water volume P is determined to be equal to or greater than the determination value PA in the countermeasure process described later, the control device 100 always selects normal processing in the situation of traveling in the hybrid mode. During the execution of such normal processing, unlike when traveling in the electric mode, there is water newly mixed into the lubricating oil due to the operation of the internal combustion engine 10. Depending on the traveling situation of the vehicle 90, the dilution water volume P may increase due to an increase in the water newly mixed into the lubricating oil. The control device 100 can execute a countermeasure process as a process for coping with such an increase in the dilution water volume P.

[0059] The control device 100 can execute a first determination process as part of the countermeasure process. In the first determination process, the control device 100 determines whether the current dilution water volume P is equal to or greater than the determination value PA. The determination value PA has been described above.

[0060] The control device 100 is capable of executing an oil temperature calculation process as part of the countermeasure process. In the oil temperature calculation process, the control device 100 calculates the current temperature L of the lubricating oil based on the operating state of the internal combustion engine 10. In the present embodiment, the control device 100 calculates the current value of the temperature L of the lubricating oil, which is a parameter representing the operating state of the internal combustion engine 10, based on the detection signal of the oil temperature sensor 45 that detects the temperature L.

[0061] The control device 100 is capable of executing a second determination process as part of the countermeasure process. In the second determination process, the control device 100 determines whether or not the current temperature L of the lubricating oil is equal to or higher than a specified temperature LA. The control device 100 stores the specified temperature LA in advance. Here, assume that the temperature L of the lubricating oil is gradually increased while water is mixed in the lubricating oil. When the temperature L of the lubricating oil reaches a temperature close to the boiling point of water, the evaporation amount of water from the lubricating oil begins to increase rapidly. The specified temperature LA is the temperature at which the evaporation amount of water from the lubricating oil begins to increase rapidly, for example, 70°C. The specified temperature LA is also a temperature at which it can be considered that the warm-up of the internal combustion engine 10 is completed. The specified temperature LA is determined in advance by, for example, experiments or simulations.

[0062] The control device 100 is capable of executing the above specific process as part of the countermeasure process. The control device 100 performs the specific process on the condition that the following three items are satisfied. (CN1) The dilution water amount P is equal to or greater than the determination value PA. (CN2) The state of charge SOC of the battery 79 is less than the above second set value V2. (CN3) The temperature L of the lubricating oil is equal to or higher than the specified temperature LA.

[0063] As described above, the specific process is a type of process for controlling the vehicle 90 in hybrid mode. That is, in the specific process, the control device 100 will deal with the dilution water amount P while continuing the operation of the internal combustion engine 10. At this time, the control device 100 controls the automatic transmission 85 so that the engine torque TE becomes smaller compared to the case of performing the normal process under the same conditions. The control of the automatic transmission 85 in this way is as already described in relation to the use of the low load map in the specific process. During the execution of the normal process, which is the comparison target with the specific process above, the dilution water amount P is in a situation where it is less than the determination value PA. Therefore, it can also be said that in the specific process, the control device 100 controls the automatic transmission 85 so that the engine torque TE becomes smaller compared to the case where the dilution water amount P is less than the determination value PA under the same conditions. That is, when the dilution water amount P is large, the control device 100 controls the automatic transmission 85 so that the engine torque TE becomes smaller compared to the case where the dilution water amount P is small while continuing the operation of the internal combustion engine 10.

[0064] As part of the countermeasure process, the control device 100 is capable of executing the above-described increase process. When (CN1) and (CN2) among the above three items are satisfied but (CN3) is not, the control device 100 performs the increase process instead of the specific process. As described above, the increase process is a type of process for controlling the vehicle 90 in hybrid mode. That is, in the increase process, the control device 100, similar to the specific process, deals with the dilution water amount P while continuing the operation of the internal combustion engine 10. At this time, the control device 100 controls the automatic transmission 85 so that the engine torque TE becomes larger compared to when performing normal processing under the same conditions. The control of the automatic transmission 85 in this way has already been described in relation to the use of the high-load map in the increase process. Incidentally, the increase process can also be described as follows from the same perspective as the above specific process. That is, in the increase process, the control device 100 controls the automatic transmission 85 so that the engine torque TE becomes larger compared to the case where the dilution water amount P is less than the determination value PA under the same conditions. In other words, when the dilution water amount P is large, the control device 100 controls the automatic transmission 85 so that the engine torque TE becomes larger compared to the case where the dilution water amount P is small while continuing the operation of the internal combustion engine 10.

[0065] As part of the countermeasure process, the control device 100 is capable of executing the electric driving process. When (CN1) among the above three items is satisfied but (CN2) is not, regardless of whether item (CN3) is satisfied or not, the control device 100 performs the electric driving process instead of the specific process. The electric driving process is a process of driving the vehicle 90 by the above-described motoring mode which is a type of electric mode. That is, in the electric driving process, the control device 100 drives the vehicle 90 only with the torque of the motor generator 82 in a state where the combustion of fuel in the internal combustion engine 10 is stopped. Also, in the electric driving process, the control device 100 sets the drive clutch 81 to the connected state. By this, the crankshaft 14 rotates together with the rotating shaft 82A of the motor generator 82. That is, the torque of the motor generator 82 is applied to the crankshaft 14.

[0066] Note that hereinafter, the specific process, the increase process, and the electric driving process may be collectively referred to as the water volume reduction process. <Specific processing procedures of the countermeasure process> When the start condition of the countermeasure process is satisfied during one trip, the control device 100 executes the countermeasure process. The start condition is that the vehicle 90 is being driven by normal processing. The control device 100 determines that the start condition is satisfied when the vehicle speed SP is greater than zero and the normal processing flag is on.

[0067] As shown in FIG. 7, when starting the countermeasure process, the control device 100 first executes the process of step S200. In step S200, the control device 100 determines whether the current dilution water volume P is equal to or greater than the determination value PA. When performing the determination in step S200, the control device 100 refers to the latest value in the time-series data of the dilution water volume P. Then, the control device 100 treats this value as the current dilution water volume P. If the dilution water volume P is less than the determination value PA (step S200: NO), the control device 100 temporarily terminates the series of processes of the countermeasure process. In this case, if the start condition is satisfied, the control device 100 executes the process of step S200 again. Note that the process of step S200 is the first determination process.

[0068] On the other hand, in step S200, when the current dilution water volume P is equal to or greater than the determination value PA (step S200: YES), the control device 100 advances the process to step S210. In step S210, the control device 100 determines whether it is possible to switch the driving mode of the vehicle 90 from the hybrid mode to the motor-only mode. Specifically, the control device 100 determines whether the state of charge SOC of the battery 79 is equal to or greater than the second set value V2. When the state of charge SOC of the battery 79 is equal to or greater than the second set value V2 (step S210: YES), the control device 100 advances the process to step S220.

[0069] In step S220, the control device 100 starts the electric driving process. That is, the control device 100 switches the driving mode of the vehicle 90 to the motor driving mode. Then, the control device 100 continues to drive the vehicle 90 in the motor driving mode hereafter. When the control device 100 executes the process of step S220, it proceeds to step S230. Note that the control device 100 does not change the driving mode or the type of water volume reduction process midway until it executes step S240 hereafter. The same applies to step S320 and step S330 described later.

[0070] On the other hand, in step S210, when the state of charge SOC of the battery 79 is less than the second set value V2 (step S210: NO), the control device 100 proceeds to step S310. Then, in step S310, the control device 100 determines whether the current temperature L of the lubricating oil is equal to or higher than the specified temperature LA. When making the determination in step S310, the control device 100 calculates the latest temperature L of the lubricating oil received from the oil temperature sensor 45 as the current temperature L of the lubricating oil. Then, when the current temperature L of the lubricating oil is equal to or higher than the specified temperature LA (step S310: YES), the control device 100 proceeds to step S320. Note that the process of step S310 also serves as an oil temperature calculation process and a second determination process.

[0071] In step S320, the control device 100 switches the process content from the normal process to the specific process while maintaining the hybrid mode. Then, the control device 100 continues to drive the vehicle 90 by the specific process hereafter. When the control device 100 executes the process of step S320, it proceeds to step S230.

[0072] On the one hand, in step S310, when the temperature L of the current lubricating oil is less than the specified temperature LA (step S310: NO), the control device 100 proceeds with the process to step S330. Then, in step S330, the control device 100 switches the processing content from the normal process to the increasing process while maintaining the hybrid mode. And the control device 100 continues to drive the vehicle 90 by the increasing process hereafter. When the control device 100 executes the process of step S330, it proceeds with the process to step S230.

[0073] In step S230, the control device 100 determines whether the current dilution water volume P is less than the end value PB. The control device 100 stores the end value PB in advance. The end value PB is a value determined in advance by, for example, experiments or simulations as a value at which the dilution water volume P becomes sufficiently small and the water volume reduction process can be terminated. When making the determination in step S230, the control device 100 grasps the current dilution water volume P in the same manner as in step S200. And when the current dilution water volume P is greater than or equal to the end value PB (step S230: NO), the control device 100 executes the process of step S230 again. After that, the control device 100 repeats the process of step S230 until the current dilution water volume P becomes less than the end value PB. And when the current dilution water volume P becomes less than the end value PB (step S230: YES), the control device 100 proceeds with the process to step S240.

[0074] In step S240, the control device 100 terminates the water volume reduction process that has been performed so far. And the control device 100 resumes the normal process. That is, hereafter, the control device 100 resumes driving the vehicle 90 in the hybrid mode by the normal process or the normal electric mode. After that, the control device 100 once terminates the series of processes for the countermeasure process. After that, if the start condition for the countermeasure process is satisfied, the control device 100 performs the process of step S200 again.

[0075] The above is the details of the countermeasure process. Note that the period required for the dilution water volume P to decrease to less than the end value PB after starting the water volume reduction process is, for example, about several minutes. It is possible for the vehicle 90 to stop during the execution of these water volume reduction processes. When the vehicle 90 stops during the execution of the water volume reduction process, the control device 100 proceeds to step S240 of the process at that time and ends the countermeasure process. If the vehicle 90 stops, similar to the case described by the transition of the dilution water volume P in the electric mode, the water newly mixed into the lubricating oil will be substantially eliminated.

[0076] <Actions of the Embodiment> (A) Regarding the setting process During one trip, the control device 100 switches the target charge rate V of the battery 79 according to the temporal change trend of the dilution water volume P. Then, when the dilution water volume P is on an increasing trend (step S120: YES), for future countermeasures, the control device 100 switches the target charge rate V from the first set value V1 to the second set value V2 (step S140). Along with this, the charge rate SOC of the battery 79 gradually increases toward the second set value V2. By doing this, when the dilution water volume P reaches the determination value PA in the future, it becomes easier to realize the switching to the motoring mode in step S210 of the countermeasure process.

[0077] (B) Regarding the electric driving process Now, assume that the increasing trend of the dilution water amount P continues and the dilution water amount P reaches the determination value PA (step S200: YES). At this time, assume that the charge rate SOC of the battery 79 has increased to the second set value V2 (step S210: YES). In this case, the control device 100 performs electric driving processing as the water amount reduction processing (step S220). That is, the control device 100 switches the driving mode of the vehicle 90 from the hybrid mode to the motoring mode. Then, the control device 100 stops fuel injection and ignition in the internal combustion engine 10 to stop the combustion of the air-fuel mixture. By this, new water mixing into the crankcase 28 and thus into the lubricating oil is substantially eliminated. Here, since the internal combustion engine 10 has been driven until before the start of the electric driving processing, the temperature L of the lubricating oil at the start of the electric driving processing is basically in a high state. Further, in the electric driving processing, the crankshaft 14 is rotated by the torque of the motor generator 82. This rotation of the crankshaft 14 stirs the lubricating oil. This can promote an increase in the temperature L of the lubricating oil. Therefore, during the execution of the electric driving processing, the temperature L of the lubricating oil is maintained in a high state. And the state where the amount of water evaporated from the lubricating oil is large continues. Since new water mixing into the lubricating oil is substantially eliminated and the evaporation of water from the lubricating oil continues, the dilution water amount P decreases.

[0078] (C) Regarding specific processing When the increasing trend of the dilution water amount P continues and the dilution water amount P reaches the determination value PA (step S200: YES), depending on the situation, the charge rate SOC of the battery 79 may not have reached the second set value V2 (step S210: NO). Suppose that at this time, the temperature L of the lubricating oil is equal to or higher than the specified temperature LA (step S310: YES). In this case, the control device 100 performs a specific process as the water amount reduction process. That is, the control device 100 switches the processing content from the normal process to the specific process while maintaining the hybrid mode (step S320). The situation where the process proceeds to step S320 is as follows. That is, although the temperature L of the lubricating oil is high and the evaporation amount of water from the lubricating oil is large, the amount of water newly mixed into the lubricating oil is large enough to exceed that, resulting in a situation where the dilution water amount P is large. For example, after the warm-up of the internal combustion engine 10 is completed, a situation where the engine torque TE and thus the engine load factor KL continue to be high can be cited. Under such circumstances, the control device 100 will perform a specific process.

[0079] As described above, in the specific process using the low-load map as the shift map, the engine torque TE per unit period becomes small. Along with this, the engine load factor KL and thus the pressure in the cylinder 11 decrease. Then, the gas leaking from the cylinder 11 into the crankcase 28 decreases. At the same time, the water mixed into the lubricating oil reaching the crankcase 28 together with such gas decreases. On the other hand, in the specific process, since the operation of the internal combustion engine 10 continues, the high temperature state of the lubricating oil temperature L is continuously maintained from before the start of the specific process. Moreover, in the specific process, the engine speed NE increases in relation to the shift map used. By this, a further increase in the temperature L of the lubricating oil through the agitation of the lubricating oil by the crankshaft 14 is expected. Therefore, the state where the amount of water evaporated from the lubricating oil is large continues. The amount of water newly mixed into the lubricating oil decreases, and the evaporation of water from the lubricating oil continues, so that the dilution water amount P decreases.

[0080] (D) Regarding the increase process When the dilution water amount P increases to the determination value PA (step S200: YES), the following situation may occur. That is, in addition to the state where the state of charge SOC of the battery 79 has not reached the second set value V2 (step S210: NO), the temperature L of the lubricating oil is further less than the specified temperature LA (step S310: NO). In this case, the control device 100 switches the processing content from the normal processing to the increase processing while maintaining the hybrid mode (step S330). The situation where the process proceeds to step S330 is, for example, a situation where the warm-up of the internal combustion engine 10 is not completed and the temperature L of the lubricating oil is relatively low. In this case, since the temperature L of the lubricating oil is low, the amount of water evaporated from the lubricating oil decreases. And accordingly, the dilution water amount P can become equal to or more than the determination value PA. Under such circumstances, the control device 100 performs the increase processing.

[0081] As described above, in the increase processing using the high load map, the engine torque TE per unit period increases. By this, the engine load factor KL increases, and the temperature L of the lubricating oil rapidly increases together with the temperature of the entire internal combustion engine 10. Then, the amount of water evaporated from the lubricating oil increases. By this, the dilution water amount P decreases.

[0082] <Effects of the Embodiment> (1) As described in (C) above, when performing the specific processing, the amount of water newly mixed into the lubricating oil can be reduced. The control device 100 performs such specific processing when the temperature L of the lubricating oil is high. By performing such specific processing in a situation where the amount of water evaporated from the lubricating oil is large to reduce the amount of water mixed into the lubricating oil, the dilution water amount P can be rapidly decreased.

[0083] (2) As described in (D) above, when performing the increase processing, the temperature L of the lubricating oil can be rapidly increased. Therefore, the control device 100 performs the increase processing when the temperature L of the lubricating oil is low. By performing the increase processing, a situation where water hardly evaporates from the lubricating oil can be eliminated. And the dilution water amount P can be rapidly decreased.

[0084] (3) When the dilution water amount P increases and the state of charge (SOC) of the battery 79 is relatively high, the control device 100 performs electric driving processing. As described in (B) above, when the electric driving processing is performed, in the internal combustion engine 10, newly generated water and thus water newly mixed into the lubricating oil are substantially eliminated. On the other hand, the temperature L of the lubricating oil is maintained at a high level through agitation of the lubricating oil by the crankshaft 14 that rotates together with the motor generator 82. Therefore, the dilution water amount P can be rapidly decreased.

[0085] <Modified Example> Note that the present embodiment can be implemented with the following modifications. The present embodiment and the following modified examples can be implemented in combination with each other within a technically non - conflicting range.

[0086] ·Regarding the setting process, the method for calculating the predicted water volume PY is not limited to the examples of the above embodiments. Any method for calculating the predicted water volume PY may be used as long as the diluted water volume P after a predetermined period can be appropriately calculated. For example, the predicted water volume PY may be calculated using regression analysis. In this case, a regression line of the diluted water volume P is calculated in orthogonal coordinates with time on the X-axis and the diluted water volume P on the Y-axis. Then, the slope of the regression line may be multiplied by a predetermined period. The predicted water volume PY may be calculated without using the history of the diluted water volume P. For example, the predicted water volume PY may be calculated based on the driving state of the vehicle 90. Here, when the acceleration state of the vehicle 90 continues, the engine load factor KL of the internal combustion engine 10 continues to increase, so the diluted water volume P may increase later. Taking such points into account, for example, a map representing the relationship between the duration of the state where the forward acceleration of the vehicle 90 is greater than zero and the diluted water volume P after a predetermined period from the current state may be created. Then, the predicted water volume PY may be calculated based on such a map. The forward acceleration may be, for example, the differential value of the vehicle speed SP, or an acceleration sensor may be provided on the vehicle 90 to detect it. Also, when calculating the predicted water volume PY, information on the driving habits of the occupants may be used. For example, assume that the diluted water volume P tends to increase near a certain predetermined value after a predetermined period after a certain specific operation by the occupant. In this case, on the condition that the operation has occurred, the predicted water volume PY after a predetermined period from the time when the operation occurred may be calculated as a predetermined value. Such a predetermined value may be learned at any time during the driving of the vehicle 90.

[0087] ·The predetermined period for calculating the predicted water volume PY can be changed as appropriate. The predetermined period only needs to consider the following matter. That matter is that it is possible to secure a period required to increase the state of charge SOC of the battery 79 to such an extent that electric driving can be performed.

[0088] · As the threshold value of the predicted water volume PY used in step S120 of the setting process, a value different from the determination value PA used in step S200 of the countermeasure process may be adopted. For example, the above threshold value may be smaller than the determination value PA. In this case, the target charge rate V can be switched to the second set value V2 at an earlier stage to increase the charge rate SOC of the battery 79. The above threshold value only needs to be a value suitable for increasing the charge rate SOC of the battery 79 in advance to cope with the future increase in the predicted water volume PY.

[0089] · The method of determining the second set value V2 is not limited to the one considering the specified distance as in the above embodiment. For example, as in the modification example described later, if the second set value V2 is not used as the threshold value for the determination in step S210 of the countermeasure process, the second set value V2 may be determined regardless of the driving distance by the electric driving process. Even in this case, if the second set value V2 is set as high as possible, it becomes easier to promote the charging of the battery 79. If the charge rate SOC of the battery 79 is high, the opportunity to use the electric driving process as the water volume reduction process increases.

[0090] · Regarding the specific process performed in the countermeasure process, the content of the low load map is not limited to the example of the above embodiment. That is, in the low load map, not all shift lines need to be shifted to the side with a higher vehicle speed SP compared to the normal map. For example, only some of the shift lines among the plurality of shift lines may be shifted to the side with a higher vehicle speed SP compared to the normal map. Also, different low load maps may be prepared for each dilution water volume P. When comparing the low load map and the normal map for the same vehicle speed SP and the same accelerator operation amount ACC, the low load map only needs to have at least a part of the region where a smaller gear shift stage is selected compared to the normal map. With such a low load map, it can be said that the following can be realized in the specific process. That is, the gear ratio set for the automatic transmission 85 can be increased compared to the case of performing the normal process under the same conditions.

[0091] ·Similar to the above modification example, the content of the high-load map is not limited to the example of the above embodiment. That is, when comparing the high-load map with the normal map for the same vehicle speed SP and the same accelerator operation amount ACC, it is sufficient that at least a part of the region where a larger gear stage is selected exists in the high-load map compared to the normal map. With such a high-load map, it can be said that the following can be achieved in the increase process. That is, it can be said that the gear ratio set for the automatic transmission 85 can be made smaller compared to the case of performing normal processing under the same conditions.

[0092] ·The content of the specific processing is not limited to the example of the above embodiment. In the specific processing, other aspects may be adopted instead of or in addition to the aspects of the above embodiment. Even when other aspects are adopted, in the specific processing, it is sufficient that the engine torque TE can be made smaller compared to the case of performing normal processing under the same conditions. As another aspect adopted in the specific processing, for example, one using the motor generator 82 may be adopted. Here, when the motor generator 82 is being driven in power running, the motor generator 82 is configured to apply torque to the crankshaft 14 of the internal combustion engine 10. As another aspect adopted in the specific processing, the target motor torque when the motor generator 82 is being driven in power running may be increased by a certain value compared to the case of performing normal processing under the same conditions. In this case, the ratio of the target engine torque in the target shaft torque becomes smaller. Therefore, in this aspect, the engine torque TE per unit period becomes smaller compared to the case of performing normal processing under the same conditions. By reducing the engine torque TE, similar to the above embodiment, the amount of water newly mixed into the lubricating oil is reduced.

[0093] ·As another aspect to be adopted in the specific process, for example, one using a lock-up clutch 84 may be adopted. Here, the lock-up clutch 84 is a torque applying device to which torque is applied from the crankshaft 14 of the internal combustion engine 10. The connection / disconnection state of this lock-up clutch 84 is switched according to the hydraulic pressure from the hydraulic mechanism 86. In the connected state, the lock-up clutch 84 directly connects the pump impeller 83A and the turbine liner 83B as described in the above embodiment. On the other hand, in the disconnected state, the lock-up clutch 84 disconnects the pump impeller 83A and the turbine liner 83B. Now, when the lock-up clutch 84 is switched from the connected state to the disconnected state under the situation where the required driving force and thus the target system output are the same, the shaft torque JT and thus the engine torque TE decrease, and the engine rotational speed NE increases. Utilizing this characteristic, the following aspect may be adopted. That is, in the normal process, the lock-up clutch 84 is set in the connected state, while in the specific process, the lock-up clutch 84 is set in the disconnected state. By doing so, in the specific process, the engine torque TE can be made smaller compared to the case of performing the normal process under the same conditions.

[0094] ·The content of the increase process is not limited to the examples of the above embodiment. In the increase process, instead of or in addition to the aspects of the above embodiment, other aspects may be adopted. Even when other aspects are adopted, in the increase process, it is sufficient that the engine torque TE can be made larger compared to the case of performing the normal process under the same conditions. For example, as another aspect instead of the aspects of the above embodiment, the target motor torque when the motor generator 82 is operated in the power running mode may be made smaller by a certain value compared to the case of performing the normal process under the same conditions. In this case, the ratio of the target engine torque to the target shaft torque increases. Therefore, in this aspect, the engine torque TE per unit period becomes larger compared to the case of performing the normal process under the same conditions. By increasing the engine torque TE, the temperature L of the lubricating oil can be rapidly increased as in the above embodiment.

[0095] ·The vehicle 90 may sometimes decelerate while in the hybrid mode. As another aspect of the increase process, for example, the regenerative brake during deceleration may be prohibited. Prohibiting the regenerative brake reduces the opportunity to charge the battery 79. As a result, the state of charge (SOC) of the battery 79 tends to be lower, and the chance that the SOC of the battery 79 falls below the target charge rate V also increases. Accordingly, the opportunity to charge the battery 79 by generating electricity with the motor generator 82 using the power of the internal combustion engine 10 increases. When generating electricity with the motor generator 82 using the power of the internal combustion engine 10, the engine torque TE increases by the amount of the generated electricity. Therefore, the mode of prohibiting the regenerative brake is also effective as an increase process. Incidentally, when the vehicle 90 decelerates while in the hybrid mode, the internal combustion engine 10 may perform fuel cut or may be idling. Idling means operating the internal combustion engine 10 at the minimum engine rotational speed NE at which the internal combustion engine 10 can operate independently.

[0096] ·Regarding the motoring mode, it is not essential to stop the combustion of the air-fuel mixture in the internal combustion engine 10. That is, in the motoring mode, the crankshaft 14 may be rotated by the motor generator 82 while the combustion of the air-fuel mixture in the internal combustion engine 10 continues. At this time, the internal combustion engine 10 is driven in a state where the torque output by the internal combustion engine 10 is limited, such as idling.

[0097] ·In the electric driving process, the vehicle 90 may be driven in the normal electric mode instead of the motoring mode. ·The mode of determining whether or not it is possible to switch to the electric mode in step S210 of the countermeasure process is not limited to the example of the above embodiment. For example, the possibility of switching to the electric mode may be determined based on a threshold value different from the second set value V2. The determination in step S210 may be made in consideration of not only the SOC of the battery 79 but also the current required driving force.

[0098] ·Depending on the SOC of the battery 79, the electric driving process may be switched to another water amount reduction process during the execution of the electric driving process. ·The ways to determine the end of the specific process, the increase process, and the electric driving process are not limited to the examples of the above embodiments. For example, the specific process may end when a predetermined period of time has elapsed since the start of the specific process. In this case, the above-mentioned predetermined period may be set to an appropriate value in consideration of the decreasing rate of the dilution water amount P. The same applies to the timing of ending the motoring process and the increase process. The continuation periods until the end may be set to different lengths for the specific process, the increase process, and the electric driving process.

[0099] ·It is not essential to use the electric driving process in the coping process. That is, the processes of step S210 and step S220 in the coping process may be abolished. And when the determination in step S200 is YES, the specific process or the increase process may be performed regardless of the magnitude of the state of charge SOC of the battery 79. If the electric driving process is abolished from the coping process, it is not necessary to switch the target state of charge V to the second set value V2 according to the predicted water amount PY in order to increase the target state of charge V. That is, the setting process may be abolished. In this case, for example, the target state of charge V may be set to the first set value V1 through one trip, or the target state of charge V may be changed from the first set value V1 to another value according to the situation.

[0100] ·It is not essential to use the increase process in the coping process. That is, the processes of step S330 and step S310 in the coping process may be abolished. And regardless of the magnitude of the temperature L of the lubricating oil, when the dilution water amount P is equal to or greater than the determination value PA, the dilution water amount P may be decreased by the specific process. In addition to abolishing the electric driving process from the coping process as in the above modification example, the increase process may be abolished, or only the increase process may be abolished without abolishing the electric driving process.

[0101] · The method of determining the determination value PA can be changed as appropriate. The determination value PA may be any value that can determine the necessity of a measure for reducing the dilution water amount P. The determination value PA does not have to be a fixed value and may be variably set according to the situation. When the dilution water amount P is large, it is sufficient if specific processing can be performed so that the engine torque TE becomes smaller than when the dilution water amount is small.

[0102] · The method of determining the specified temperature LA can be changed as appropriate. The specified temperature LA may be lower than the temperature at which the warm-up of the internal combustion engine 10 is completed. In terms of the relationship between the amount of water evaporated from the lubricating oil and the amount newly mixed into the lubricating oil, it is sufficient if the specified temperature LA is set so that a more appropriate one of the specific processing and the increasing processing can be selected.

[0103] · The calculation method of the dilution water amount P is not limited to the example of the above embodiment. The dilution water amount P may be calculated based on the operating state of the internal combustion engine 10. For example, the cooling water temperature W may be considered when calculating the dilution water amount P. The cooling water temperature W reflects the temperature of the wall surface partitioning the cylinder 11 in the cylinder block 26. And according to the temperature of this wall surface, the ease of condensation on the wall surface and thus the amount of water reaching the crankcase 28 can also change. From this perspective, the cooling water temperature W is also effective as a parameter in calculating the dilution water amount P. When calculating the dilution water amount P, a sensor for detecting the amount of water in the lubricating oil may be used. In this case, such a sensor may be attached to the internal combustion engine 10. The dilution water amount P may be calculated using a mapping pre-learned by machine learning.

[0104] · The calculation method of the temperature L of the lubricating oil is not limited to the example of the above embodiment. The temperature L of the lubricating oil may be calculated based on the operating state of the internal combustion engine 10. Instead of detecting the temperature L of the lubricating oil by a sensor, for example, it may be calculated based on parameters such as the integrated value of the intake air amount GA since the internal combustion engine 10 starts and the cooling water temperature W. When adopting such an aspect, a map representing the relationship between these parameters and the temperature L of the lubricating oil may be created in advance by experiment or simulation.

[0105] · The configuration of the internal combustion engine 10 is not limited to the example of the above embodiment. For example, the number of cylinders 11 may be changed from that of the above embodiment. The fuel injection valve 17 may be changed to a type that supplies fuel to the cylinder 11 via the intake passage 15. The fuel injected by the fuel injection valve 17 is not limited to hydrogen, and may be, for example, gasoline. The configuration of the blow-by gas treatment mechanism may be changed from that of the above embodiment. The blow-by gas treatment mechanism only needs to be able to reflux the blow-by gas from the crankcase 28 to the intake passage 15. In discharging moisture from the crankcase 28, a configuration other than the blow-by gas treatment mechanism may be used. For example, a ventilation passage communicating the crankcase 28 with the outside of the internal combustion engine 10 may be provided. Then, the water evaporated from the lubricating oil may be discharged to the outside through such a ventilation passage.

[0106] · The overall configuration of the vehicle 90 is not limited to the example of the above embodiment. For example, the vehicle 90 may adopt a continuously variable transmission as the automatic transmission. In this case, the contents of the normal map, low-load map, and high-load map may be changed according to the continuously variable transmission. Similar to the case of a stepped automatic transmission, a low-load map may be created so that the gear ratio set for the automatic transmission can be increased compared to performing normal processing under the same conditions. The high-load map may also be created from the same viewpoint as in the above embodiment.

[0107] ·In addition to an internal combustion engine, the vehicle may have two motor generators as drive sources. When adopting such a configuration, the content of the basic control of the vehicle's power transmission system by normal processing, specific processing, and increase processing may be changed according to the vehicle's configuration. When the vehicle has an internal combustion engine and two motor generators as drive sources, for example, it is conceivable to connect these internal combustion engine and two motor generators using a planetary gear mechanism. The planetary gear mechanism has a sun gear of an external gear, a ring gear of an internal gear, a plurality of pinion gears interposed between the sun gear and the ring gear, and a carrier that supports the plurality of pinion gears. The sun gear, the ring gear, and the carrier are rotatable coaxially. The crankshaft of the internal combustion engine is connected to the carrier. The first motor generator, which is one of the two motor generators, is connected to the sun gear. The second motor generator, which is the other of the two motor generators, is connected to the internal combustion engine and the first motor generator via the ring gear. The first motor generator functions as a starter motor for the internal combustion engine. That is, the first motor generator can apply torque to the crankshaft. The second motor generator functions as a driving motor. That is, the second motor generator can apply torque to the drive wheels.

[0108] In the case of the above configuration, for example, as a specific process, the assist torque for running by the second motor generator may be increased compared to the normal process. In this case, the engine torque TE for obtaining the same required driving force can be reduced. Conversely, as an increase process, the assist torque for running by the second motor generator may be reduced compared to the normal process. In this case, the engine torque TE for obtaining the same required driving force can be increased. Such specific processes and increase processes may be adopted. Based on the determination value PA and the specified temperature LA described in the above embodiment, it is possible to determine the necessity of executing each process, and these specific processes and increase processes may be performed as necessary. Those that can change the engine torque TE according to the change of their own control content, such as the second motor generator described above, are included in the torque applying device that transmits and receives torque between the crankshaft of the internal combustion engine. Note that as a specific process, torque may be applied from the first motor generator to the crankshaft.

[0109] · The vehicle may have only an internal combustion engine as a drive source and may not have a motor generator. Even in such a vehicle, if it has a torque applying device such as an automatic transmission that can transmit and receive torque with the internal combustion engine, specific processing or increase processing can be realized when the dilution water amount P increases. For example, consider a vehicle that has only an internal combustion engine as a drive source and has a stepped automatic transmission connected to the internal combustion engine. In this vehicle, similar to the above embodiment, it is assumed that the control device controls the internal combustion engine and the automatic transmission by normal processing, specific processing, and increase processing. Similar to the above embodiment, the control device basically runs the vehicle by normal processing. In such a vehicle, for example, the countermeasure processing shown in FIG. 8 may be applied. In FIG. 8, the same step numbers as those in the above embodiment are assigned to the parts that perform the same processing as in the above embodiment.

[0110] The control device starts the countermeasure process on the condition that the vehicle is running in normal operation. When starting the countermeasure process, the control device first executes the process of step S200. If the current dilution water volume P is less than the determination value PA in step S200, the control device ends the series of processes of the countermeasure process. On the other hand, if the current dilution water volume P is equal to or greater than the determination value PA, the control device advances the process to step S310. Then, when the current lubricating oil temperature L is equal to or higher than the specified temperature LA (step S310: YES), the control device starts the specific process (step S320). That is, the control device controls the automatic transmission 85 using the low-load map as the shift map. On the other hand, when the current lubricating oil temperature L is less than the specified temperature LA (step S310: NO), the control device starts the increase process (step S330). That is, the control device controls the automatic transmission using the high-load map as the shift map. After that, the control device continues the specific process or the increase process until the dilution water volume P becomes less than the end value PB. Then, when the dilution water volume P becomes less than the end value PB (step S230: YES), the control device ends the current water volume reduction process and ends the countermeasure process. The dilution water volume P may be reduced by the countermeasure process as described above. Even in such a mode, the dilution water volume P can be reduced while maintaining the required driving force and thus the output required for the internal combustion engine. When the vehicle is targeted which has only an internal combustion engine as a drive source, the charge rate SOC of the battery 79 and thus the target motor torque may be abolished from the specified parameters.

[0111] · As in the above modification example, when the vehicle has two motor generators as drive sources or the vehicle has only an internal combustion engine as a drive source, the dilution water volume P may be reduced using only the specific process without using the increase process.

[0112] <Supplementary Notes> The above-described embodiments and modification examples include the configurations described below. [Appendix 1] A vehicle having an internal combustion engine and a torque applying device capable of transmitting torque to and from the output shaft of the internal combustion engine is a control target. During operation of the internal combustion engine, based on the operating state of the internal combustion engine, a water quantity calculation process for calculating the diluted water quantity, which is the quantity of water contained in the lubricating oil of the internal combustion engine, and when the diluted water quantity is large, while continuing the operation of the internal combustion engine, a specific process for controlling the torque applying device so that the torque per unit period in the internal combustion engine becomes smaller than when the diluted water quantity is small are executed. A control device for a vehicle.

[0113] [Appendix 2] The torque applying device is an automatic transmission to which torque is applied from the output shaft of the internal combustion engine. In the specific process, the gear ratio of the automatic transmission is increased compared to when the diluted water quantity is small. The control device for a vehicle according to [Appendix 1].

[0114] [Appendix 3] The torque applying device is a motor generator capable of applying torque to the output shaft of the internal combustion engine. In the specific process, the torque applied from the motor generator to the output shaft of the internal combustion engine is increased compared to when the diluted water quantity is small. The control device for a vehicle according to [Appendix 1].

[0115] [Appendix 4] During operation of the internal combustion engine, an oil temperature calculation process for calculating the temperature of the lubricating oil of the internal combustion engine is executed based on the operating state of the internal combustion engine. When the temperature of the lubricating oil is equal to or higher than a predetermined specified temperature, the specific process is executed. The control device for a vehicle according to any one of [Appendix 1] to [Appendix 3].

[0116] [Appendix 5] When the temperature of the lubricating oil is lower than the specified temperature, instead of executing the specific process, an increasing process for controlling the torque applying device so that the torque per unit period of the internal combustion engine becomes larger than when the diluted water quantity is small while continuing the operation of the internal combustion engine when the diluted water quantity is large is executed. The control device for a vehicle according to [Appendix 4].

[0117] [Appendix 6] The vehicle has a motor generator capable of applying torque to the drive wheels of the vehicle, and a battery that supplies power to the motor generator. When the minimum value of the charge rate of the battery required to run the vehicle for a predetermined specified distance using only the torque of the motor generator among the internal combustion engine and the motor generator is set as the set value, if the charge rate of the battery is equal to or higher than the predetermined set value, instead of executing the specific process, an electric driving process of running the vehicle using only the torque of the motor generator is executed. A vehicle control device according to any one of [Appendix 1] to [Appendix 5].

Explanation of Signs

[0118] 10…Internal combustion engine 14…Crankshaft 72…Drive wheels 79…Battery 82…Motor generator 85…Automatic transmission 90…Vehicle 100…Control device

Claims

1. A vehicle having an internal combustion engine and a motor generator capable of applying torque to the output shaft of the internal combustion engine is a control target, During operation of the internal combustion engine, A water quantity calculation process for calculating the dilution water quantity, which is the quantity of water contained in the lubricating oil of the internal combustion engine, based on the operating state of the internal combustion engine; When the dilution water quantity is large, while continuing the operation of the internal combustion engine, a specific process for controlling the motor generator so that the torque per unit period in the internal combustion engine becomes smaller than when the dilution water quantity is small; Execute, In the specific process, the torque applied from the motor generator to the output shaft of the internal combustion engine is increased compared to when the dilution water quantity is small. A control device for a vehicle.

2. A vehicle having an internal combustion engine and a torque application device capable of transmitting torque between the internal combustion engine and the output shaft of the internal combustion engine is a control target, During operation of the internal combustion engine, A water quantity calculation process for calculating the dilution water quantity, which is the quantity of water contained in the lubricating oil of the internal combustion engine, based on the operating state of the internal combustion engine; An oil temperature calculation process for calculating the temperature of the lubricating oil based on the operating state of the internal combustion engine is executed, When the temperature of the lubricating oil is equal to or higher than a predetermined specified temperature, when the dilution water quantity is large, while continuing the operation of the internal combustion engine, a specific process for controlling the torque application device so that the torque per unit period in the internal combustion engine becomes smaller than when the dilution water quantity is small is executed, When the temperature of the lubricating oil is lower than the specified temperature, instead of executing the specific process, when the dilution water quantity is large, while continuing the operation of the internal combustion engine, an increase process for controlling the torque application device so that the torque per unit period in the internal combustion engine becomes larger than when the dilution water quantity is small is executed. A control device for a vehicle.

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