JP6730655B2 - Control device for hybrid vehicle - Google Patents

Description

The present invention relates to a technique for estimating a diluted fuel amount in lubricating oil of an internal combustion engine mounted on a hybrid vehicle.

BACKGROUND ART Conventionally, a technique has been developed in which fuel vaporized gas mixed in lubricating oil of an internal combustion engine is recirculated to an intake system to suppress dilution of the lubricating oil.
For example, in Patent Document 1, when the diluted fuel amount of the lubricating oil is increased, the internal combustion engine is operated to raise the temperature of the lubricating oil to evaporate the fuel from the lubricating oil in the oil pan and generate the fuel evaporative emission gas. Is recirculated to the intake passage via the return passage.

Japanese Patent No. 5381422

However, in the internal combustion engine configured to recirculate the fuel mixed in the lubricating oil into the intake system as in the above-mentioned Patent Document 1, by recirculating the fuel evaporative gas to the intake system, the inflow amount of the fuel into the cylinder is reduced. However, there is a problem in that the accuracy of the air-fuel ratio control of the internal combustion engine deteriorates due to the change.
Therefore, it is conceivable to estimate the temperature of the lubricating oil or the diluted fuel amount, which is the amount of fuel contained in the lubricating oil, calculate the recirculation amount of the fuel evaporative gas, and correct the air-fuel ratio control.

However, in a hybrid vehicle or a plug-in hybrid vehicle, in a vehicle capable of running in the EV mode without operating the internal combustion engine, the operating frequency of the internal combustion engine is low, and the temperature of the internal combustion engine becomes 0 when the diluted fuel amount of the lubricating oil becomes zero. It is highly possible that the case of not rising to a certain degree can be repeated. Therefore, the estimation error of the diluted fuel amount in the lubricating oil is accumulated, the estimation accuracy is reduced, and it becomes difficult to accurately correct the air-fuel ratio control.

The present invention has been made to solve such a problem, and an object thereof is to improve the estimation accuracy of the diluted fuel amount in the lubricating oil of an internal combustion engine in a hybrid vehicle or a plug-in hybrid vehicle. The purpose of the present invention is to provide a control device for a hybrid vehicle.

In order to achieve the above-mentioned object, a control device for a hybrid vehicle according to claim 1 of the present invention includes a first traveling mode in which the internal combustion engine mounted in the vehicle is driven while traveling, and the internal combustion engine is stopped. A second control mode for a hybrid vehicle that selects and executes a second traveling mode in which the vehicle is driven and driven by a first rotary electric motor mounted on the vehicle, the vehicle generating power by driving the internal combustion engine. And a power generation control unit that controls the power generated by the second rotary motor, and the control device for the hybrid vehicle controls the diluted fuel amount that is the fuel amount mixed in the lubricating oil of the internal combustion engine. A presumed diluted fuel amount estimation unit, a warm-up determination unit that determines whether or not a warm-up completion condition including that the engine temperature of the internal combustion engine is equal to or higher than a predetermined temperature is satisfied, and the warm-up completion condition is A warm-up incomplete cumulative time detection unit that detects the cumulative operating time of the internal combustion engine in the unestablished state, the cumulative operating time is equal to or longer than a first predetermined time, and the second traveling mode is selected. While operating, the internal combustion engine is operated and operated until the warm-up completion condition of the internal combustion engine is satisfied, and the current estimated value of the diluted fuel amount by the diluted fuel amount estimation unit is set to 0 , The power generation control unit is configured to increase the power generated by the second rotary motor during the operation of the internal combustion engine when the cumulative operating time is equal to or longer than a second predetermined time that is greater than the first predetermined time. And an operation control unit for controlling the.

Further, preferably, the vehicle includes a battery that charges electric power generated by the second rotary motor to supply power to the first rotary motor, and a charge amount detection unit that detects a charge amount of the battery. The second rotary electric motor drives the internal combustion engine with the electric power supplied from the battery, and the operation control unit controls the accumulated operation time to be equal to or more than the second predetermined time, and the charge amount. Is greater than or equal to a predetermined charge amount, it is preferable to execute motoring forcibly driving the internal combustion engine by the second rotary electric motor with the fuel supply to the internal combustion engine stopped.

Further, preferably, the vehicle includes a battery that charges electric power generated by the second rotary motor to supply power to the first rotary motor, and a charge amount detection unit that detects a charge amount of the battery. The operation control unit may not perform the operation of the internal combustion engine when the accumulated operation time is less than the second predetermined time and the charge amount is equal to or more than the predetermined charge amount. ..

According to the present invention, when the accumulated operation time in the state where the warm-up completion condition of the internal combustion engine is not satisfied becomes the first predetermined time or more, an error is accumulated in the estimated value of the diluted fuel amount by the diluted fuel amount estimation unit. Although it may increase, the actual diluted fuel amount can be set to 0 because the internal combustion engine is operated and the internal combustion engine is operated until the warm-up completion condition is satisfied even if the second traveling mode is selected. it can. Since the estimated value of the diluted fuel amount is set to 0, it is possible to eliminate the error between the actual diluted fuel amount and the estimated value. Thus, in a hybrid vehicle that frequently shifts from the first traveling mode to the second traveling mode before the internal combustion engine is completely warmed up, it is possible to prevent the error in the estimated value of the diluted fuel amount from continuing to accumulate. Therefore, the accuracy of the estimated value of the diluted fuel amount can be improved.
Further, when the accumulated operation time in the state where the warm-up completion condition is not satisfied is the second predetermined time which is larger than the first predetermined time or more, the power generated by the second rotary motor is reduced when the internal combustion engine is operating. Since it is increased, the load of the internal combustion engine is increased, the engine temperature is quickly raised, and the error in the estimated value of the diluted fuel amount can be quickly eliminated.

1 is a schematic configuration diagram of a plug-in hybrid vehicle according to an embodiment of the present invention. It is a block diagram of an engine and a control system according to the present embodiment. It is a table for calculation of an estimated oil temperature. It is a table for calculation of the amount of dilution fuel increase. It is a table for calculation of the amount of dilution fuel reduction. It is a flow chart which shows the warm-up completion judgment control point. It is a flowchart which shows the calculation point of the warm-up incomplete accumulated time. It is a flow chart which shows the selection control point of the operating mode of the engine. It is a flowchart which shows the control point at the time of operating mode selection. 6 is a time chart showing an example of changes in estimated oil temperature, warm-up completion determination, and warm-up incomplete cumulative time. It is a map showing the selection result of the operating mode of the engine. It is a time chart which shows an example of changes of the estimated diluted fuel amount, the actual diluted fuel amount, and the estimated oil temperature when the EV mode and the series mode or the parallel mode are repeated.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a schematic configuration diagram of a plug-in hybrid vehicle (hereinafter referred to as vehicle 1) according to an embodiment of the present invention.
The vehicle 1 of the present embodiment, which employs the control device for an internal combustion engine of the present invention, can drive the front wheels 3 by the output of the engine 2 (internal combustion engine) to run, and also has an electric front motor 4 that drives the front wheels 3. The four-wheel drive vehicle includes a (first rotary electric motor) and an electric rear motor 6 (first rotary electric motor) that drives the rear wheels 5.

The engine 2 can drive the drive shaft 8 of the front wheels 3 via the front transaxle 7, and can also drive the motor generator 9 (second rotary electric motor) via the front transaxle 7 to generate electric power. Has become. Further, the engine 2 and the front wheels 3 are connected via a clutch 16 arranged inside the front transaxle 7.
The front motor 4 is driven by being supplied with high-voltage electric power from the drive battery 11 and the motor generator 9 mounted on the vehicle 1 via the front control unit 10 (power generation control unit), and via the front transaxle 7. Drive the drive shaft 8 of the front wheel 3.

The rear motor 6 is driven by being supplied with high-voltage electric power from the drive battery 11 via the rear control unit 12, and drives the drive shaft 14 of the rear wheel 5 via the rear transaxle 13.
The electric power generated by the motor generator 9 can charge the drive battery 11 via the front control unit 10 and can also supply electric power to the front motor 4 and the rear motor 6.

The drive battery 11 is composed of a secondary battery such as a lithium-ion battery and has a battery module (not shown) composed of a plurality of battery cells. Further, the driving battery 11 includes a charging rate detecting unit 11a (charging amount detecting unit) that detects a charging rate SOC (corresponding to the charging amount of the present invention) of the driving battery 11.
The front control unit 10 has a function of controlling an output of the front motor 4 and a power generation amount and an output of the motor generator 9 based on a control signal from the hybrid control unit 20 mounted on the vehicle.

The rear control unit 12 has a function of controlling the output of the rear motor 6 based on a control signal from the hybrid control unit 20.
The engine control unit 22 is a control device of the engine 2 and includes an input/output device, a storage device (ROM, RAM, non-volatile RAM, etc.), a central processing unit (CPU), a timer, and the like. The engine control unit 22 controls the fuel injection amount, the fuel injection timing, the intake air amount, etc. in the engine 2 based on the control signal (request output) from the hybrid control unit 20 to control the drive of the engine 2.

Further, the vehicle 1 is provided with a fuel tank 17 that stores fuel for supplying fuel to the engine 2 and a charger (not shown) that charges the drive battery 11 with an external power source.
The hybrid control unit 20 is a control device for performing comprehensive control of the vehicle 1, and includes an input/output device, a storage device (ROM, RAM, nonvolatile RAM, etc.), a central processing unit (CPU), a timer, and the like. It is configured to include.

The front control unit 10, the rear control unit 12, and the engine control unit 22 are connected to the input side of the hybrid control unit 20, and detection and operation information from these devices is input.
On the other hand, on the output side of the hybrid control unit 20, the front control unit 10, the rear control unit 12, the engine control unit 22, and the clutch 16 of the front transaxle 7 are connected.

Then, the hybrid control unit 20 calculates a vehicle required output required for driving the vehicle 1 on the basis of various detected amounts such as the accelerator operation information degree of the vehicle 1 and various operation information, and the engine control unit 22, the front Control signals are transmitted to the control unit 10 and the rear control unit 12 to switch between running modes (EV mode, series mode, parallel mode), outputs of the engine 2, the front motor 4, and the rear motor 6, power generated by the motor generator 9, and The output and connection/disconnection of the clutch 16 in the front transaxle 7 are controlled.

In the EV mode (second running mode), the engine 2 is stopped and the front motor 4 and the rear motor 6 are driven by the electric power supplied from the drive battery 11 to run.
In the series mode (first traveling mode), the clutch 16 of the front transaxle 7 is disengaged, and the engine 2 operates the motor generator 9. Then, the front motor 4 and the rear motor 6 are driven by the electric power generated by the motor generator 9 and the electric power supplied from the drive battery 11 to drive the vehicle. Further, in the series mode, the rotation speed of the engine 2 is set to an efficient value, and the power generated by the surplus output is supplied to the drive battery 11 to charge the drive battery 11.

In the parallel mode (first running mode), the clutch 16 of the front transaxle 7 is connected, and mechanical power is transmitted from the engine 2 via the front transaxle 7 to drive the front wheels 3. Further, the front motor 4 and the rear motor 6 are driven by the electric power generated by operating the motor generator 9 by the engine 2 and the electric power supplied from the driving battery 11 to drive the vehicle.

The hybrid control unit 20 sets the traveling mode to the parallel mode in an efficient region of the engine 2, such as a high speed region. In the region excluding the parallel mode, that is, in the medium-low speed region, the EV mode and the series mode are switched based on the state of charge SOC (charge amount) of the drive battery 11.
FIG. 2 is a configuration diagram of the engine 2 and the control system according to the present embodiment.

The engine 2 according to the present embodiment is, for example, a gasoline engine including a plurality of cylinders, and FIG. 2 shows one of the plurality of cylinders.
As shown in FIG. 2, the engine 2 is provided with a positive crankcase ventilation system 31. The positive crankcase ventilation system 31 includes a recirculation passage 35 that communicates the space 32 in the crankcase of the engine 2 and the space 33 in the rocker cover with the intake passage 34, and a crankcase ventilation valve that opens and closes the recirculation passage 35. And 36. The return passage 35 connects the intake passage 34 on the downstream side of the throttle valve 37 and the space 33 in the rocker cover. The space 33 in the rocker cover and the space 32 in the crankcase communicate with each other through a communication passage 39 around the cylinder 38. The crankcase ventilation valve 36 can adjust the flow rate of the fuel evaporative gas passing through the recirculation passage 35 in accordance with the pressure inside the intake passage 34. The unburned fuel mixed with the lubricating oil and passing between the cylinder 38 and the piston 40 is stored on the oil pan 41 together with the lubricating oil. The unburned fuel evaporated from the lubricating oil on the oil pan 41 is returned as blow-by gas from the space 32 in the crankcase to the intake passage 34 via the communication passage 39, the space 33 in the rocker cover, and the return passage 35, and again. It is made to flow into the cylinder and burned.

As shown in FIG. 2, on the input side of the engine control unit 22, an air flow sensor 42 that detects the intake air flow rate Vai of the engine 2, a rotation speed sensor 43 (crank angle sensor) that detects the actual rotation speed of the engine 2, A water temperature sensor 44 that detects an engine water temperature Tw, which is the temperature of the cooling water of the engine 2, is connected and inputs various detection signals. Further, the engine control unit 22 inputs the accelerator operation amount of the vehicle, the vehicle speed, the charging rate SOC of the drive battery 11, and the traveling mode via the hybrid control unit 20.

On the other hand, the output side of the engine control unit 22 is connected with a throttle valve 37, a fuel injection valve 45, an ignition device (ignition coil, ignition plug) 46, a warning light 47 and the like. Further, the engine control unit 22 outputs various signals to the hybrid control unit 20 for forced engine drive, power generation control, and motoring execution.
The engine control unit 22 controls the opening of the throttle valve 37, the fuel injection amount by the fuel injection valve 45, and the fuel injection timing so that the target output torque of the engine 2 calculated based on various signals such as the accelerator operation amount is obtained. , And controls the ignition timing of the ignition device 46.

The vehicle 1 of this embodiment is capable of motoring. The motoring cuts off the fuel supply to the engine 2 and supplies electric power from the driving battery 11 to the motor generator 9 to operate the motor generator 9, thereby forcibly driving the engine 2. Due to the motoring, the engine 2 is driven without fuel consumption, and the oil temperature (lubricating oil temperature) rises slightly. The charging rate of the driving battery 11 is reduced by this motoring.

Further, the engine control unit 22 of the present embodiment includes a diluted fuel amount estimation unit 50, a warm-up incomplete cumulative time detection unit 51, and an operation control unit 52.
The diluted fuel amount estimation unit 50 estimates the diluted fuel amount which is the fuel amount mixed in the lubricating oil stored in the oil pan 41 of the engine 2.
3 shows an example of a table for calculating the estimated oil temperature To, FIG. 4 shows an example of a table for calculating the amount Vfu of diluted fuel increase, and FIG. 5 shows an example of a table for calculation of the amount Vfd of diluted fuel decrease.

The diluted fuel amount estimation unit 50 of the engine control unit 22 stores the tables shown in FIGS. 3 to 5 in advance, and inputs the intake air flow rate Vai and the engine water temperature Tw at every predetermined time (for example, several msec) when the engine 2 is operating. Then, the diluted fuel amount increase amount Vfu and the diluted fuel amount decrease amount Vfd are calculated and integrated from 0 to estimate the current diluted fuel amount (estimated diluted fuel amount Vfe).

Specifically, the diluted fuel amount estimation unit 50 first calculates the estimated oil temperature To (engine temperature) based on the intake air flow rate Vai using the table shown in FIG. As shown in FIG. 3, the estimated oil temperature To increases primarily as the intake air flow rate Vai increases.
Further, the diluted fuel amount estimation unit 50 uses the table shown in FIG. 4 to calculate the diluted fuel amount increase amount Vfu based on the engine water temperature Tw. As shown in FIG. 4, the diluted fuel amount increase amount Vfu becomes 0 when the engine water temperature Tw is high. As the engine water temperature Tw decreases, the diluted fuel amount increase amount Vfu rapidly increases.

Further, the diluted fuel amount estimation unit 50 uses the table shown in FIG. 5 to calculate the diluted fuel amount reduction amount Vfd based on the estimated oil temperature To obtained using FIG. As shown in FIG. 5, the diluted fuel amount decrease amount Vfd is 0 when the estimated oil temperature To is low and is higher than 0 when the estimated oil temperature To is medium and high. As the estimated oil temperature To rises, the diluted fuel amount decrease amount Vfd sharply increases.
Then, the diluted fuel amount estimation unit 50 adds the diluted fuel amount increase amount Vfu to the previous estimated diluted fuel amount Vfe(n-1) stored in the memory, as shown in the following equation (1). At the same time, the diluted fuel amount decrease amount Vfd is subtracted to calculate the current estimated diluted fuel amount Vfe(n). The calculated current estimated diluted fuel amount Vfe(n) is rewritten in the memory and used for the next calculation of the diluted fuel amount Vf(n+1).

Vfe(n)=Vfe(n-1)+Vfu-Vfd (1)
The warm-up incomplete cumulative time detection unit 51 is the cumulative operation time of the engine 2 in the warm-up incomplete state such as when the series mode, the parallel mode, and the EV mode are repeatedly switched over in a short time. The warm-up incomplete cumulative time ta is detected.
FIG. 6 is a flowchart showing the procedure of the warm-up completion determination control. FIG. 7 is a flowchart showing the procedure for calculating the warm-up incomplete cumulative time ta.

The warm-up incomplete cumulative time detection unit 51 calculates the warm-up completion determination control shown in FIG. 6 and the warm-up incomplete cumulative time ta shown in FIG. 7 for a predetermined time (for example, several msec to several sec) when the vehicle power is turned on. Repeat each time.
As shown in FIG. 6, first in step S10, the warm-up incomplete cumulative time detection unit 51 determines that the estimated oil temperature To estimated by the diluted fuel amount estimation unit 50 is equal to or higher than the first predetermined temperature T1 (predetermined temperature). It is determined whether or not there is. The first predetermined temperature T1 may be set to a temperature at which the fuel in the lubricating oil on the oil pan 41 evaporates after warming up is completed. When the estimated oil temperature To is equal to or higher than the first predetermined temperature T1, the process proceeds to step S20. If the estimated oil temperature To is lower than the first predetermined temperature T1, the process proceeds to step S60.

In step S20, the warm-up determination oil temperature condition is set to ON. Then, the process proceeds to step S30.
In step S30, it is determined whether or not the warm-up determination oil temperature condition has been turned ON and the third predetermined time t3 or more has continued. The third predetermined time t3 may be set to a time required for the estimated oil temperature To to become equal to or higher than the first predetermined temperature T1 and to completely evaporate the fuel in the lubricating oil on the oil pan 41. When the warm-up determination oil temperature condition is ON and the third predetermined time t3 or more continues, the process proceeds to step S40. If the time during which the warm-up determination oil temperature condition is ON has not continued (is less than) for the third predetermined time t3 or more, the process proceeds to step S50.

In step S40, the warm-up completion determination is turned on. Then, this routine ends.
In step S50, the warm-up completion determination is turned off. Then, this routine ends.
In step S60, the warm-up determination oil temperature condition is set to OFF. Then, the process proceeds to step S70.
In step S70, the warm-up completion determination is turned off. Then, this routine ends.

The control from step S10 to step S70 in the warm-up incomplete cumulative time detection unit 51 corresponds to the warm-up determination unit of the present invention.
Further, as shown in FIG. 7, the warm-up incomplete cumulative time detecting unit 51 first determines in step S100 whether or not the warm-up completion determination is OFF. If the warm-up completion determination is OFF, the process proceeds to step S110. If the warm-up completion determination is not OFF (ON), the process proceeds to step S130.

In step S110, it is determined whether the engine 2 is operating. When the engine 2 is operating, the process proceeds to step S120. If the engine 2 is not in operation, this routine ends.
In step S120, the warm-up incomplete cumulative time ta is incremented. The warm-up incomplete cumulative time ta is stored in the memory, and the warm-up incomplete cumulative time detecting unit 51 repeats this routine for the stored warm-up incomplete cumulative time ta. Increase the given time. Then, this routine ends.

In step S130, the warm-up incomplete cumulative time ta stored in the memory is reset to zero.
The control from step S100 to step S130 in the warm-up incomplete cumulative time detection unit 51 corresponds to the warm-up incomplete cumulative time detection unit of the present invention.
The operation control unit 52 selects the operation mode of the engine 2 based on the warm-up incomplete cumulative time ta calculated by the warm-up incomplete cumulative time detecting unit 51 and the charging rate SOC of the drive battery 11.

FIG. 8 is a flowchart showing the procedure for selecting and controlling the operation mode of the engine 2. FIG. 9 is a flowchart showing a control procedure when the operation mode is selected.
When the vehicle power is turned on, the operation control unit 52 repeatedly executes the operation mode selection control shown in FIG. 8 and the operation mode selection control shown in FIG. 9 every predetermined time (for example, several msec to several sec).

As shown in FIG. 8, the operation control unit 52 first determines in step S200 whether or not the warm-up completion determination is ON. If the warm-up completion determination is ON, the process proceeds to step S260. If the warm-up completion determination is not ON (OFF), the process proceeds to step S210.
In step S210, it is determined whether or not the warm-up incomplete cumulative time ta is equal to or longer than the second predetermined time t2. The second predetermined time t2 may be set to a time such that the error between the estimated diluted fuel amount Vfe and the actual diluted fuel amount Vft is near the upper limit value within the allowable range. If the warm-up incomplete cumulative time ta is equal to or longer than the second predetermined time t2, the process proceeds to step S250. If the warm-up incomplete cumulative time ta is less than the second predetermined time t2, the process proceeds to step S220.

In step S220, it is determined whether or not the warm-up incomplete cumulative time ta is equal to or longer than the first predetermined time t1. The first predetermined time t1 is a value smaller than the second predetermined time t2, and may be set to a time required to eliminate the error between the estimated diluted fuel amount Vfe and the actual diluted fuel amount Vft. If the warm-up incomplete cumulative time ta is equal to or longer than the first predetermined time t1, the process proceeds to step S240. If the warm-up incomplete cumulative time ta is less than the first predetermined time t1, the process proceeds to step S230.

In step S230, the operation mode of the engine 2 is set to the normal mode. The normal mode here is a mode in which there is little error between the estimated diluted fuel amount Vfe and the actual diluted fuel amount Vft, and it is not necessary to reset the estimated diluted fuel amount Vfe to zero. Then, this routine ends.
In step S240, the first forced mode is set. The first forced mode is a mode in which the engine 2 is forcibly operated to reset the estimated diluted fuel amount Vfe to 0, but it is a mode in which it is not necessary to immediately reduce the actual diluted fuel amount Vft. Then, this routine ends.

In step S250, the second forced mode is set. The second forced mode is a mode in which the engine 2 is forcibly operated in order to reset the estimated diluted fuel amount Vfe to 0, and further, the actual diluted fuel amount Vft needs to be rapidly reduced. Then, this routine ends.
In step S260, the operating mode of the engine 2 is set to the normal mode. Further, the estimated diluted fuel amount Vfe is reset to 0. Then, this routine ends.

As shown in FIG. 9, the operation control unit 52 first determines in step S300 whether or not the operation control unit 52 is in the second forced mode first. If it is the second forced mode, the process proceeds to step S310. If it is not the second forced mode, the process proceeds to step S350.
In step S310, the current charging rate SOC of the driving battery 11 is input, and it is determined whether or not the charging rate SOC is equal to or higher than a predetermined charging rate SOC1. The predetermined charge rate SOC1 may be set to a value close to full charge, which is not chargeable. The predetermined charging rate SOC1 has a hysteresis, and when the charging rate SOC decreases, it is preferable to set the predetermined charging rate SOC1 to a lower value than when it rises. As a result, even if the state of charge SOC varies near the predetermined state of charge SOC1, the switching frequency in this step is reduced. If the state of charge SOC is equal to or higher than the predetermined state of charge SOC1, the process proceeds to step S320. If the state of charge SOC is less than the predetermined state of charge SOC1, the process proceeds to step S330.

In step S320, the operation mode of the engine 2 is set to the motoring mode in which the motoring is executed. Then, this routine ends.
In step S330, the EV mode is prohibited. That is, the engine 2 is in the operating state. Then, the process proceeds to step S340.
In step S340, a control signal is output to the hybrid control unit 20 so as to increase the amount of power generated by the motor generator 9 as compared with the normal time. Then, this routine ends.

In step S350, it is determined whether the first forced mode is set. If it is the first forced mode, the process proceeds to step S360. If it is not the first forced mode, the process proceeds to step S370.
In step S360, the EV mode is prohibited, that is, the engine 2 is in the operating state. The amount of power generated by the motor generator 9 is in the normal state. Then, this routine ends.

In step S370, the normal mode is set. Then, this routine ends.
Further, the engine control unit 22 corrects the air-fuel ratio control based on the estimated diluted fuel amount Vfe which is the estimated value of the diluted fuel amount and the estimated oil temperature To which is the estimated temperature of the lubricating oil. For example, as the estimated diluted fuel amount Vfe is high and the estimated oil temperature To is high, the amount of blow-by gas that is generated from the lubricating oil and flows into the intake passage 34 through the positive crankcase ventilation system 31 is increased. The fuel injection amount from the injection valve 45 may be reduced. Further, the engine control unit 22 may display the engine operating mode selected when the air-fuel ratio control is corrected or the selected engine operating mode by the warning light 47 to notify the occupant.

FIG. 10 is a time chart showing a transition example of the estimated oil temperature To, the warm-up completion determination, and the warm-up incomplete cumulative time ta.
As a result of the above control, for example, as shown in FIG. 10, when the estimated oil temperature To becomes equal to or higher than the first predetermined temperature T1 (a in FIG. 10) and the third predetermined time t3 continues, the warm-up completion determination is ON. (B in FIG. 10). Further, when the estimated oil temperature To becomes lower than the first predetermined temperature T1, the warm-up completion determination is turned off (c in FIG. 10). When the warm-up completion determination is ON, the warm-up incomplete cumulative time ta becomes zero. When the warm-up completion determination becomes OFF, the warm-up incomplete cumulative time ta increases, and when the warm-up incomplete cumulative time ta becomes the first predetermined time t1 or more, the EV mode is prohibited and the engine forced operation is performed. (Operation of the internal combustion engine) is performed (d in FIG. 10), and the estimated oil temperature To rises. When the estimated oil temperature To becomes equal to or higher than the first predetermined temperature T1 (e in FIG. 10) and continues for the third predetermined time t3, the warm-up completion determination is turned ON, and the engine forced operation ends (FIG. 10). F) inside.

FIG. 11 is a map showing the selection result of the operation mode of the engine 2 shown in FIGS. 6 to 9 described above.
By selecting the operation mode by controlling as shown in FIGS. 6 to 9, the normal mode, the first forced mode, the second forced mode, based on the warm-up incomplete cumulative time ta and the state of charge SOC, The motoring mode is selected and executed.

As shown in FIG. 11, when the warm-up incomplete cumulative time ta is less than the first predetermined time t1, the first forced mode and the second forced mode for forcibly operating the engine 2 are not executed. Mode. When the warm-up incomplete cumulative time ta is not less than the first predetermined time t1 and less than the second predetermined time t2, the EV mode is prohibited and the engine 2 is forcibly operated when the charging rate SOC is less than the predetermined charging rate SOC1. Let However, when the warm-up incomplete cumulative time ta is equal to or longer than the first predetermined time t1 and shorter than the second predetermined time t2, and the charging rate is equal to or higher than the predetermined charging rate SOC1, the normal mode is set.

When the warm-up incomplete cumulative time ta is equal to or longer than the second predetermined time t2, the EV mode is prohibited and the engine 2 is forcibly driven when the charging rate SOC is less than the predetermined charging rate SOC1, and the amount of power generated by the motor generator 9 is increased. When the charging rate SOC is equal to or higher than the predetermined charging rate SOC1, motoring is performed.
FIG. 12 is a time chart showing an example of changes in the estimated diluted fuel amount Vfe, the actual diluted fuel amount Vft, and the estimated oil temperature To when the EV mode and the series mode or the parallel mode are repeated. Note that ∇ in FIG. 12 indicates the engine start timing.

As shown in FIG. 12, when the oil temperature (estimated oil temperature To) is low such as immediately after the engine is started, the diluted fuel amount changes and the actual diluted fuel amount Vft changes when the engine is operating in the series mode or the parallel mode. And the estimated diluted fuel amount Vfe increases. When the execution time of the series mode or the parallel mode is secured for a long time, the oil temperature rises and the actual diluted fuel amount Vft becomes zero.

In the present embodiment, when the warm-up incomplete cumulative time ta becomes equal to or longer than the first predetermined time t1, the EV mode is prohibited and the engine 2 is forcibly operated even if the EV mode execution condition is satisfied, and the oil temperature is increased. Can be increased so that the actual diluted fuel amount Vft is set to 0, and the error of the estimated diluted fuel amount Vfe can be set to 0. Therefore, even when the EV mode and the series mode or the parallel mode are repeated in a short time, the warm-up can be surely completed every time the first predetermined time t1 elapses, and the estimated diluted fuel amount Vfe It is possible to prevent the accumulation of the error of (1) and improve the accuracy of the estimated diluted fuel amount Vfe.

As a result, the accuracy of the air-fuel ratio control can be improved by correcting the air-fuel ratio control based on the estimated diluted fuel amount Vfe and the estimated oil temperature To, and particularly the accuracy of the air-fuel ratio control when the engine temperature is low is enhanced. It is possible to reduce fuel consumption and improve engine operation stability.
Further, when the warm-up incomplete cumulative time ta exceeds the first predetermined time t1 and becomes the second predetermined time t2 or more, it is highly possible that the error of the estimated diluted fuel amount Vfe further increases. Therefore, in this embodiment, not only the engine 2 is operated, but the amount of power generation is increased. As a result, the load of the engine 2 is increased, the oil temperature is quickly raised to reach the first predetermined temperature T1, and the error of the estimated diluted fuel amount Vfe can be quickly eliminated.

Further, when the warm-up incomplete cumulative time ta exceeds the first predetermined time t1 and becomes the second predetermined time t2 or more, the charging rate SOC of the driving battery 11 is the predetermined charging rate SOC1 or more close to full charge. In this case, since the driving battery 11 cannot be charged even if power is generated, the fuel supply to the engine 2 is stopped and the motor generator 9 forcibly drives the engine 2 to perform motoring. .. As a result, the charging rate SOC of the drive battery 11 can be reduced to prevent overcharging, and the oil temperature of the engine 2 can be raised slightly. When the charging rate SOC of the driving battery 11 becomes less than the predetermined charging rate SOC1, the engine 2 is operated as described above to increase the amount of power generation, and the oil temperature is quickly raised, and the error of the estimated diluted fuel amount Vfe is increased. Will be resolved.

Although the description of the embodiment of the invention has been completed, the embodiment of the invention is not limited to this embodiment.
In the present embodiment, the normal mode, the first compulsory mode, the second compulsory mode, and the motoring mode are switched based on the warm-up incomplete cumulative time ta and the state of charge SOC. It suffices that the normal mode and the forced mode (first and second) can be switched based on ta.

Further, in the present embodiment, the engine control unit 22 includes the diluted fuel amount estimation unit 50, the warming-up incomplete cumulative time detection unit 51, and the operation control unit 52, but the hybrid control unit 20 and the like are mounted on the vehicle 1. It may be provided in another control unit.
Further, in the present embodiment, the present invention is applied to the plug-in hybrid vehicle that can switch between the EV mode, the parallel mode, and the series mode. However, at least the parallel mode or the series mode for operating the engine and the EV It is widely applicable to hybrid vehicles that can be switched between modes in which the engine does not operate, such as modes.

1 vehicle 2 engine (internal combustion engine)
4 Front motor (first rotary motor)
6 Rear motor (first rotary motor)
9 Motor generator (second rotary motor)
10 Front control unit (power generation control unit)
11 Drive battery (battery)
11a Charging rate detector (charge amount detector)
20 Hybrid control unit 22 Engine control unit 50 Diluted fuel amount estimation unit 51 Warm-up incomplete cumulative time detection unit (Warm-up determination unit, warm-up incomplete cumulative time detection unit)
52 operation control unit 53 power generation control unit

Claims (3)

A first traveling mode in which the internal combustion engine installed in the vehicle is driven while driving and a second traveling mode in which the internal combustion engine is stopped and the vehicle is driven by the first rotary electric motor installed in the vehicle are selected. A control device for a hybrid vehicle that executes
The vehicle includes a second rotary motor that generates power by driving the internal combustion engine, and a power generation control unit that controls power generated by the second rotary motor.
The control device for the hybrid vehicle is
A diluted fuel amount estimation unit for estimating a diluted fuel amount, which is the amount of fuel mixed in the lubricating oil of the internal combustion engine,
A warm-up determination unit that determines whether or not a warm-up completion condition including that the engine temperature of the internal combustion engine has reached a predetermined temperature or higher,
A warm-up incomplete cumulative time detection unit that detects a cumulative operation time of the internal combustion engine in a state where the warm-up completion condition is not satisfied;
When the cumulative operating time is equal to or longer than a first predetermined time and the second traveling mode is selected, the internal combustion engine is operated to operate until a warm-up completion condition for the internal combustion engine is satisfied. Then, the current estimated value of the diluted fuel amount by the diluted fuel amount estimation unit is set to 0, and when the accumulated operation time is equal to or longer than a second predetermined time period that is greater than the first predetermined time period, An operation control unit that controls the power generation control unit to increase the power generated by the second rotary motor during the operation of the internal combustion engine ;
Hybrid vehicle control apparatus characterized by comprising a. The vehicle includes a battery that charges electric power generated by the second rotary motor and supplies power to the first rotary motor, and a charge amount detection unit that detects a charge amount of the battery,
The second rotary electric motor drives the internal combustion engine with electric power supplied from the battery,
When the operation accumulated time is equal to or more than the second predetermined time and the charge amount is equal to or more than a predetermined charge amount, the operation control unit stops the fuel supply to the internal combustion engine in the second state. The control device for a hybrid vehicle according to claim 1, wherein motoring for forcibly driving the internal combustion engine is executed by the rotary electric motor of No. 2. The vehicle includes a battery that charges electric power generated by the second rotary motor and supplies power to the first rotary motor, and a charge amount detection unit that detects a charge amount of the battery,
The operation control unit does not perform the operation of the internal combustion engine when the operation accumulated time is less than the second predetermined time and the charge amount is equal to or more than a predetermined charge amount. The control device for a hybrid vehicle according to claim 2.

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