JP7622602B2 - Electric vehicle control device - Google Patents

Description

This disclosure relates to a control device for an electric vehicle.

Conventionally, there are known control devices for electric vehicles equipped with an internal combustion engine and a generator capable of driving the internal combustion engine (see, for example, Patent Document 1 and Patent Document 2). The control device for an electric vehicle in Patent Document 1 uses a friction torque learning value corresponding to the coolant temperature of the internal combustion engine in order to stabilize the idle speed after the internal combustion engine is started. In addition, the control device for an electric vehicle in Patent Document 2 detects the friction torque when cranking the internal combustion engine and starts the internal combustion engine by adding a torque equivalent to this friction torque.

JP 2005-155357 A JP 2015-164831 A

The electric vehicle control device of Patent Document 1 cannot correct the torque when starting the internal combustion engine. As a result, there is a risk that the output of the internal combustion engine will decrease immediately after starting the internal combustion engine. On the other hand, in the electric vehicle control device of Patent Document 2, there is a risk that the output of the internal combustion engine will be insufficient at start-up due to changes in oil temperature and water temperature. This may result in poor starting of the internal combustion engine, or even if the internal combustion engine does start, it may take time for the internal combustion engine to reach the target output after starting. In such an electric vehicle control device, it is preferable that the internal combustion engine can quickly achieve the target output after starting so that the generator can generate electricity immediately after starting the internal combustion engine.

The objective of this disclosure is to provide a control device for an electric vehicle that can easily achieve the target output quickly after the internal combustion engine starts.

The control device for an electric vehicle according to the present disclosure is a control device for an electric vehicle having an internal combustion engine including a throttle valve and a first rotating electric machine capable of driving the internal combustion engine. The control device for the electric vehicle executes a first learning control that learns an intake air amount at the start of the internal combustion engine based on a difference between a first output calculated as an output at the start of the internal combustion engine, which is a period until firing for starting the internal combustion engine is executed , which is assumed based on a water temperature of the internal combustion engine , and a second output that is an output of the internal combustion engine driven by the first rotating electric machine at the start of the internal combustion engine, when the first rotating electric machine drives the internal combustion engine to motor it. The control device for the electric vehicle controls the throttle valve to obtain the intake air amount learned by the first learning control , and then executes fuel injection and firing for starting the internal combustion engine .

This control device for an electric vehicle can accurately learn the intake air volume at the start of the internal combustion engine before the internal combustion engine is started by a first learning control based on the difference between a first output calculated based on the water temperature and a second output, which is the output of the first rotating electric machine when the first rotating electric machine actually drives the internal combustion engine. This makes it easier for the internal combustion engine to quickly achieve the target output after it starts.

This disclosure provides a control device for an electric vehicle that can easily achieve the target output quickly after the internal combustion engine starts.

1 is a system diagram of an electric vehicle according to an embodiment of the present disclosure. 1 is a system diagram of an internal combustion engine according to an embodiment of the present disclosure. 4 is a flowchart showing a control procedure of a control device for an electric vehicle according to an embodiment of the present disclosure. 4 is a timing chart showing the output and rotation speed of the internal combustion engine when controlled by the control device for an electric vehicle according to an embodiment of the present disclosure.

Embodiments of the present disclosure will be described below with reference to the drawings. In the following description, the longitudinal direction of the vehicle is indicated as Q in the drawings, and the front is indicated as F. The width direction of the vehicle is indicated as P in the drawings, and the right side as viewed from the rear of the vehicle is indicated as R.

As shown in FIG. 1, the electric vehicle 1 according to this embodiment is a four-wheel drive plug-in hybrid electric vehicle (PHEV). The electric vehicle 1 has an internal combustion engine (ENG) 2, a generator (an example of a first rotating electric machine: GEN) 4, a front motor (an example of a second rotating electric machine: FrM) 6, a rear motor (RM) 8, a drive battery (BT) 10, a control device (HVECU) 20, an accelerator pedal 21, and an external charging device 22. In this embodiment, the electric vehicle 1 is an internal combustion engine transversely mounted electric vehicle 1 in which the crankshaft of the internal combustion engine 2 is arranged to extend in the vehicle width direction.

In the electric vehicle 1 of this embodiment, the front motor 6 drives the front wheel drive shaft 12a of the front wheels 12 via the transaxle 16. The rear motor 8 drives the rear wheel drive shaft 14a of the rear wheels 14 via a reduction gear 8c. The front motor 6 is connected to the drive battery 10 via a front inverter 18, and is supplied with electric power (second electric power) from the drive battery 10.

The front inverter 18 has a front motor control unit (FrMCU) 6a and a generator control unit (GCU) 4a that controls the generator 4. The front motor control unit 6a receives signals from the control unit 20 and controls the regeneration and power running of the front motor 6 so that the front motor 6 is in the desired operating state. The rear motor 8 is similarly connected to the drive battery 10 via the rear inverter 8b and is supplied with power (second power) from the drive battery 10. The rear inverter 8b has a rear motor control unit (RMCU) 8a. The rear motor control unit 8a receives signals from the control unit 20 and controls the regeneration and power running of the rear motor 8 so that the rear motor 8 is in the desired operating state.

As shown in FIG. 2, the internal combustion engine 2 has a throttle valve 2b, an intake port 2c, a fuel injection valve 2d, a water passage 2e, a water temperature sensor (an example of a water temperature detection unit) 2f, an oil pan 2g, and an oil temperature sensor (an example of an oil temperature detection unit) 2h. In this embodiment, the internal combustion engine 2 is a multi-injection type gasoline engine. The internal combustion engine 2 injects fuel using a fuel injection valve 2d arranged in the intake port 2c, and adjusts the intake air amount using the throttle valve 2b to adjust the output. Specifically, the internal combustion engine 2 obtains the atmospheric temperature detected by an air flow sensor (not shown) from the target charging efficiency Ec and calculates the target intake air amount Qt using the engine control device 2a. The engine control device 2a calculates the target throttle flow rate Qth from the target intake air amount Qt. The engine control device 2a calculates the throttle opening ThO by multiplying this target throttle flow rate Qth by a throttle flow rate coefficient Kth. In this way, the engine control device 2a adjusts the throttle opening ThO of the throttle valve 2b, thereby adjusting the amount of intake air supplied to the internal combustion engine 2. The internal combustion engine 2 may be a direct injection gasoline engine. The internal combustion engine 2 may also be a gasoline engine that uses both a multi-injection system and a direct injection system. Furthermore, the control of the throttle valve 2b may be performed by the control device 20.

The water passage 2e is a passage through which the cooling water flows to cool the internal combustion engine 2. After cooling the internal combustion engine 2, the water passage 2e passes through a radiator (not shown) and returns to the internal combustion engine 2. The water temperature sensor 2f is provided on the water passage 2e and detects the temperature of the cooling water flowing through the water passage 2e. In this embodiment, the water temperature sensor 2f is provided in the water passage 2e provided in the cylinder block, but the water temperature sensor 2f may be provided anywhere on the water passage 2e as long as it can detect the temperature of the cooling water (water temperature Wt). The oil pan 2g collects the oil supplied to the internal combustion engine 2. The internal combustion engine 2 is provided with an oil passage (not shown) to lubricate rotating parts such as the crankshaft and cool pistons. The oil temperature sensor 2h detects the temperature of the oil (oil temperature Ot). In this embodiment, the oil temperature sensor 2h is provided in the oil pan 2g, but the oil temperature sensor 2h may be provided anywhere on the oil passage as long as it can measure the temperature of the oil. In this embodiment, the water temperature sensor 2f and the oil temperature sensor 2h are electrically connected to the engine control device 2a. However, the water temperature sensor 2f and the oil temperature sensor 2h may also be electrically connected to the control device 20.

The internal combustion engine 2 drives the generator 4 via the transaxle 16. The internal combustion engine 2 is driven by the combustion of fuel supplied from a fuel tank (FUEL TANK) 23. Various devices and sensors of the internal combustion engine 2 are electrically connected to an engine control device (ENG-ECU) 2a. The engine control device 2a receives signals from the control device 20 and controls the internal combustion engine 2 to be in a desired operating state. The transaxle 16 amplifies the rotation speed of the internal combustion engine 2 and transmits it to the generator 4. The transaxle 16 of this embodiment also has a clutch 16a. The clutch 16a transmits and cuts off power between the internal combustion engine 2 and the front motor 6 and between the internal combustion engine 2 and the front wheel drive shaft 12a. The internal combustion engine 2 is connected to the front wheel drive shaft 12a via the clutch 16a of the transaxle 16 and drives the front wheel drive shaft 12a.

As shown in FIG. 1, the generator 4 is connected to the internal combustion engine 2 and generates electricity by being driven by the internal combustion engine 2. The electric power (first electric power) generated by the generator 4 can charge the drive battery 10 and can be supplied to each motor via the front inverter 18 and the rear inverter 8b. In this embodiment, the generator 4 is a motor generator, and in addition to generating electricity, it can crank or motor the internal combustion engine 2 by rotating and driving the internal combustion engine 2. When the generator 4 is driven by the internal combustion engine 2, it generates electricity by applying a load to the generator 4. On the other hand, the generator 4 is supplied with electric power from the drive battery 10 and drives the internal combustion engine 2 to crank or motor it. The generator 4 is controlled by a generator control device 4a provided in the front inverter 18. The generator control device 4a is electrically connected to the control device 20, receives a signal from the control device 20, and controls the generation and powering so that the generator 4 is in a desired operating state.

The drive battery 10 is composed of secondary batteries such as lithium ion batteries, and has a battery module (not shown) that is composed of multiple battery cells. The drive battery 10 functions as a power source for each motor. The drive battery 10 also has a battery monitoring unit (BMU) 10a. The battery monitoring unit (BMU) 10a calculates the charging rate (State Of Charge, hereinafter referred to as SOC) of the battery module, and detects the deterioration state (State Of Health, hereinafter referred to as SOH) of the battery module, the voltage Bv of the battery module, and the battery temperature Btmp. The battery monitoring unit 10a acquires the voltage Bv, charging rate SOC, deterioration state SOH, and battery temperature Btmp of the drive battery 10, and transmits them to the control device 20.

The control device 20 executes at least the following controls: control for switching between driving modes; power generation control for causing the internal combustion engine 2 to generate electricity in each driving mode; motoring control for driving the internal combustion engine 2 with the generator 4; and control for regenerative cooperative braking of the electric vehicle 1 using regenerative braking and friction braking.

In this embodiment, the control device 20 switches to one of the series mode (series driving mode), parallel mode (parallel driving mode), and EV mode (EV driving mode) by controlling the clutch 16a based on information such as the speed V, the charging rate SOC, and the accelerator opening Th. In the parallel mode, the control device 20 connects the clutch 16a and drives the front wheel drive shaft 12a by both the internal combustion engine 2 and the front motor 6. At this time, the front motor 6 is supplied with either or both of the electric power (second electric power) from the drive battery 10 and the electric power (first electric power) generated by the generator 4. Similarly, the rear motor 8 is supplied with either or both of the electric power (second electric power) from the drive battery 10 and the electric power (first electric power) generated by the generator 4 to drive the rear wheel drive shaft 14a. In EV mode, the control device 20 releases the clutch 16a and supplies power (second power) from the drive battery 10 to each motor, which drives the front wheel drive shaft 12a and the rear wheel drive shaft 14a (hereinafter referred to as each drive shaft in the specification).

In series mode, the control device 20 releases the clutch 16a, drives the generator 4 with the internal combustion engine 2, and supplies the first electric power generated by the generator 4 to each motor. If the first electric power is insufficient to drive each drive shaft, the drive battery 10 also supplies the second electric power to each motor. Note that in parallel mode and series mode, the drive battery 10 may be charged by supplying a portion of the electric power generated by the internal combustion engine 2 to the drive battery 10.

The control device 20 calculates the required power generation amount GEq as the power generation amount to be generated by the generator 4 in each driving mode of the parallel mode, the series mode, and the EV mode. The control device 20 applies a load to the generator 4 so that the required power generation amount GEq can be achieved. The control device 20 also calculates the engine required torque ETq, which is the output (torque) required of the internal combustion engine 2 so that the internal combustion engine 2 can drive the generator 4, and transmits it to the engine control device 2a. The engine control device 2a obtains the engine required torque ETq and controls the internal combustion engine 2 so that the engine required torque ETq can be achieved. The control device 20 is actually composed of a microcomputer including a calculation device, a memory, an input/output buffer, etc. The control device 20 controls each device so that the electric vehicle 1 is in a desired operating state based on signals from each sensor and various devices, as well as maps and programs stored in the memory. In this embodiment, the control device 20 executes torque-based control that calculates the torque to be output by the internal combustion engine 2 and each motor based on the driver required torque DTq described later. Therefore, in the following specification, output has the same meaning as torque.

In addition, in this embodiment, various control devices including the engine control device 2a, generator control device 4a, front motor control device 6a, rear motor control device 8a, and battery monitoring unit 10a are each provided separately from the control device 20. The various control devices are each electrically connected to the control device 20. However, the various control devices may be provided integrally with the control device 20. Like the control device 20, the various control devices are configured by microcomputers including an arithmetic unit, a memory, an input/output buffer, etc.

The accelerator pedal 21 is a pedal that is depressed by the driver of the electric vehicle 1 to control the acceleration and deceleration of the electric vehicle 1. The accelerator pedal 21 is provided with an accelerator position sensor 21a that detects the depression position. The accelerator position sensor 21a is electrically connected to the control device 20 and transmits the accelerator depression position (accelerator opening Th) to the control device 20. The control device 20 calculates the driver required torque (an example of a driver required output) DTq from the accelerator opening Th.

The external charging device 22 is a device that charges the drive battery 10 with power from an external power source of the electric vehicle 1 (hereinafter referred to as external charging in the specification). The external charging device 22 receives a supply of power, for example, from a charging facility external to the electric vehicle 1. The external charging device 22 converts the power supplied from the external power source into power suitable for charging the drive battery 10, and charges the drive battery 10.

Next, the control procedure of the control device 20 of this embodiment will be described using the flowchart of FIG. 3 and the timing chart of FIG. 4. Note that the control procedure described below may be executed by the engine control device 2a as well as the control device 20, but in this embodiment, the case where the control device 20 executes the control procedure will be described. The control device 20 starts the control operation when an ignition switch (not shown) is turned on.

As shown in FIG. 3, in step S1, the control device 20 calculates the engine required torque ETq for operating the internal combustion engine 2 and prepares to start the internal combustion engine 2. The control device 20 starts the internal combustion engine 2 when it is necessary to generate electricity using the generator 4 in the series driving mode or when switching to the parallel driving mode. When the control device 20 calculates the engine required torque ETq, it calculates a torque (an example of the first output, hereinafter referred to as the water temperature estimated torque Tw) that is assumed to be output by the internal combustion engine 2 at the time of starting the internal combustion engine 2 based on the water temperature Wt detected by the water temperature sensor 2f. The start-up of the internal combustion engine 2 refers to a period during which the internal combustion engine 2 is motored (cranked). In other words, the start-up is a period from when the control device 20 executes firing to when the internal combustion engine 2 is started. In this embodiment, the control device 20 prestores a preset oil type (e.g., 0W20) for the internal combustion engine 2, and friction torque, which is the torque for friction resistance and pump loss that is expected to occur in the internal combustion engine 2 at the water temperature Wt when using this preset oil type. The control device 20 calculates the water temperature estimated torque Tw by adding the friction torque that may occur in the internal combustion engine 2 to the engine required torque ETq. The control device 20 calculates the target intake air amount Qt to be drawn into the cylinder of the internal combustion engine 2 and the fuel injection amount from this water temperature estimated torque Tw.

In addition, the control device 20 detects the shaft torque (an example of the second output, hereinafter referred to as actual torque Tr in the specification) of the output shaft of the internal combustion engine 2 driven by the generator 4 when the generator 4 motors (cranks) the internal combustion engine 2. Since the generator 4 drives the internal combustion engine 2 when motoring (cranking), the control device 20 can detect the actual torque Tr from the amount of electricity supplied to the generator 4. Therefore, the shaft torque of the internal combustion engine 2 detected by the generator 4 corresponds to the actual torque of the output shaft of the internal combustion engine 2. Note that since the generator 4 and the internal combustion engine 2 are connected via a shaft, the output and torque of the internal combustion engine 2 can be detected by the generator 4. Therefore, the output and torque of the internal combustion engine 2 can be calculated from the output and torque of the generator 4. In other words, the output and torque of the internal combustion engine 2 can be converted to the output and torque of the generator 4. Therefore, the output and torque of the internal combustion engine 2 may be treated as substantially the same as the output and torque of the generator 4. Specifically, instead of the water temperature estimated torque Tw and actual torque Tr used as the output (torque) of the internal combustion engine 2, the following control may be executed using the corresponding output and torque of the generator 4. As shown from time t0 to time t1 in FIG. 4, in step S1, the control device 20 starts calculating the water temperature estimated torque Tw and detecting the actual torque Tr, but motoring (cranking) of the internal combustion engine 2 has not started at this time. As shown in FIG. 3, when the control device 20 detects the water temperature estimated torque Tw and the actual torque Tr, it proceeds to step S2.

In step S2, the control device 20 motors (cranks) the internal combustion engine 2 using the generator 4. As shown from time t1 to time t2 in FIG. 4, when the internal combustion engine 2 is motored (cranked), the engine speed of the internal combustion engine 2 increases. However, immediately after the internal combustion engine 2 is motored (cranked), both the water temperature estimated torque Tw and the actual torque Tr are not stable.

For this reason, the control device 20 judges whether motoring (cranking) is stable in step S3 as shown in FIG. 3. Here, the stable state of motoring (cranking) may be a state in which the fluctuation of the engine speed or engine output based on motoring (cranking) is within a predetermined range. The control device 20 may determine that the above state has been reached and motoring (cranking) is stable when a predetermined time has elapsed since motoring (cranking) was started. The control device 20 may also detect a change in the actual torque Tr and determine that motoring (cranking) is stable when the change in the actual torque Tr is within a predetermined range. The control device 20 prohibits the execution of the first learning control described later until motoring (cranking) is stable. When the control device 20 judges that motoring (cranking) is stable (step S3 YES), the control device 20 proceeds to step S4. If motoring (cranking) is not stable in step S3 (step S3 NO), the control device 20 returns to step S2 and continues motoring (cranking) of the internal combustion engine 2 until motoring (cranking) is stable.

In step S4, the control device 20 calculates the absolute value of the difference between the actual torque Tr and the water temperature estimated torque Tw, and determines whether the absolute value is equal to or greater than a predetermined torque (an example of a predetermined output) Td. In such an electric vehicle 1, the internal combustion engine 2 is stopped when the vehicle runs in EV mode or when the vehicle decelerates. For this reason, in such an electric vehicle 1, the internal combustion engine 2 is repeatedly started and restarted. As a result, when there is a discrepancy between the actual torque Tr and the water temperature estimated torque Tw, in addition to cases where the oil type is different from the set type, there are also cases where only the water temperature Wt has increased and the oil temperature Ot has not increased. Therefore, in step S4, the control device 20 determines whether there is a discrepancy between the actual torque Tr and the water temperature estimated torque Tw, and uses this for the calculation of the first learning control described later. The control device 20 calculates the absolute value of the difference between the actual torque Tr and the water temperature estimated torque Tw, and if the absolute value is greater than the predetermined torque Td (step S4 YES), the process proceeds to step S5.

In step S5, the control device 20 determines whether the absolute value of the difference between the water temperature Wt and the oil temperature Ot is within a predetermined temperature Dtmp. The oil temperature Ot takes a longer time to rise after the internal combustion engine 2 is started than the water temperature Wt. In particular, in an electric vehicle 1 in which the internal combustion engine 2 is repeatedly restarted, such a deviation between the oil temperature Ot and the water temperature Wt is likely to occur. Therefore, in step S5, the control device 20 determines whether there is a deviation between the oil temperature Ot and the water temperature Wt, and executes control according to the presence or absence of a deviation. If the control device 20 determines that the absolute value of the difference between the water temperature Wt and the oil temperature Ot is greater than the predetermined temperature Dtmp (step S5 NO), the process proceeds to step S6.

In step S6, the control device 20 starts the first learning control. From time t2 to time t3 in FIG. 4, the absolute value of the difference between the actual torque Tr and the water temperature estimated torque Tw during motoring (cranking) is calculated, and a graph is shown showing the values of the actual torque Tr and the water temperature estimated torque Tw when the absolute value is greater than a predetermined torque Td. In the graph in FIG. 4, the water temperature estimated torque Tw is a torque higher than the actual torque Tr. In other words, the graph in FIG. 4 shows a case where the actual friction torque is greater than the friction torque used for the water temperature estimated torque Tw.

When there is a deviation of a predetermined torque Td or more between the actual torque Tr and the water temperature estimated torque Tw, the control device 20 executes a first learning control that records the differential torque between the actual torque Tr and the water temperature estimated torque Tw as a first learning value. The first learning control may record the differential torque between the actual torque Tr and the water temperature estimated torque Tw for a predetermined period (e.g., between time t2 and time t3 in FIG. 4) after motoring (cranking) has stabilized, and calculate the average value of these as the first learning value. Alternatively, the differential torque between the actual torque Tr and the water temperature estimated torque Tw at time t3 or immediately before time t3 may be recorded as the first learning value.

Furthermore, the control device 20 may shorten the time (execution time) for executing the first learning control as the driver required torque DTq during motoring (cranking) is higher. The longer the learning time, the more accurate the learning. However, when the driver required torque DTq is high, it may be better to prioritize drivability over learning. In this way, the control device 20 may control to prioritize either learning accuracy or drivability depending on the driver required torque DTq. In any case, the control device 20 starts the first learning control during motoring (cranking) and records the first learning value. After starting the first learning control, the control device 20 proceeds to step S7.

In step S7, the control device 20 determines whether external charging is occurring. If external charging is not occurring (step S7: NO), the control device 20 proceeds to step S8. In step S8, the control device 20 acquires a first learning value. As described above, the first learning value is the differential torque between the actual torque Tr and the water temperature estimated torque Tw. After acquiring the first learning value, the control device 20 proceeds to step S9.

In step S9, the control device 20 corrects the target intake air amount Qt by reflecting the first learning value. Specifically, the control device 20 calculates a correction amount of the target intake air amount Qt to be supplied to the internal combustion engine 2 based on the differential torque. For example, when the water temperature estimated torque Tw is a torque higher than the actual torque Tr, the friction torque is larger than expected. Therefore, the differential torque is a negative value. Therefore, in order to increase the target intake air amount Qt, the control device 20 executes correction control to increase the throttle opening ThO of the throttle valve 2b. The control device 20 executes control to increase the fuel injection amount in accordance with the increase in the target intake air amount Qt. On the other hand, when the water temperature estimated torque Tw is a torque lower than the actual torque Tr, the friction torque is smaller than expected. Therefore, the control device 20 executes control to reduce the target intake air amount Qt, reduce the throttle opening ThO, and reduce the fuel injection amount. After the control device 20 corrects the target intake air volume Qt to reflect the first learning value and executes correction control of the opening of the throttle valve 2b, it ignites the spark plug 2i in step S10 to start firing.

As shown in FIG. 4 from time t3 to time t4, in this embodiment, firing and fuel injection are performed during this period. Specifically, fuel injection and firing are performed at time t3. In this embodiment, as shown in the change in water temperature estimated torque Tw at time t3 in FIG. 4, when firing is performed at time t3, a combustion torque due to the intake air amount reflecting the first learning value is added. The control device 20 starts calculating the engine estimated torque Tw1 including the combustion torque reflecting the first learning value. Note that, in the period from time t3 to time t4, taking into account the effect of firing, the control device 20 prohibits the execution of the first learning control. When firing is performed, the control device 20 proceeds to step S11.

In step S11, the control device 20 determines that complete explosion has occurred. Complete explosion refers to a state in which the mixture in the cylinder of the internal combustion engine 2 has been ignited. In this embodiment, the control device 20 determines complete explosion by detecting whether the rotation of the internal combustion engine 2 has stabilized. However, the control device 20 may also determine complete explosion by whether the fluctuation of the actual torque Tr has decreased. If complete explosion has occurred, the control device 20 proceeds to step S12.

In step S12, the control device 20 executes a second learning control to learn the intake air amount based on the difference between the engine estimated torque Tw1 (an example of the third output) of the internal combustion engine 2 reflecting the first learning value and the actual torque Tr after the internal combustion engine 2 has completely exploded. At this time, the control device 20 detects the actual torque Tr based on the power generation amount of the generator 4. As shown after time t4 in FIG. 4, the control device 20 stabilizes the operation of the internal combustion engine 2 while maintaining the internal combustion engine 2 at a predetermined rotation speed and a predetermined load after the internal combustion engine 2 has completely exploded. In this embodiment, the control device 20 maintains the engine at a predetermined rotation speed while keeping the engine required torque ETq constant, and applies a predetermined load to the generator 4 to generate electricity. At this time, the oil temperature Ot rises and approaches the water temperature Wt.

As shown after time t4 in FIG. 4, the control device 20 records the second learning value based on the difference between the engine estimated torque Tw1 and the actual torque Tr (see X in FIG. 4). As shown in the graph of the second learning value in FIG. 4, the control device 20 records the second learning value in real time and corrects the target intake air amount Qt and the throttle opening ThO in real time. This corrects the reduction in friction torque that corresponds to the increase in oil temperature Ot. As a result, the actual torque Tr (the exerted output) can be quickly matched to the engine required torque ETq. After executing the second learning control, the control device 20 returns the process to step S1 and performs the same control procedure the next time the internal combustion engine 2 is restarted.

In step S4, the control device 20 calculates the absolute value of the difference between the actual torque Tr and the water temperature estimated torque Tw. If it determines that the absolute value is smaller than the predetermined torque Td (step S4 NO), the process proceeds to step S13, where firing is performed, and the process proceeds to step S11. If the absolute value of the difference between the actual torque Tr and the water temperature estimated torque Tw is smaller than the predetermined torque Td, the effect of the deviation between the water temperature Wt and the oil temperature Ot on the start of the internal combustion engine 2 is small. Therefore, in step S11, the control device 20 does not execute the first learning control, and promptly starts the internal combustion engine 2 by full combustion.

In step S5, if the control device 20 determines that the absolute value of the difference between the water temperature Wt and the oil temperature Ot is smaller than the predetermined temperature (step S5 YES), the control device 20 proceeds to step S14 and determines that an oil type different from the setting has been put into the internal combustion engine 2. If there is no deviation between the water temperature Wt and the oil temperature Ot, the water temperature estimated torque Tw should be close to the actual torque Tr. However, if there is no deviation between the water temperature Wt and the oil temperature Ot but the difference between the actual torque Tr and the water temperature estimated torque Tw is equal to or greater than a predetermined value, it is considered that an oil type with a different viscosity than that used to calculate the water temperature estimated torque Tw has been used. Therefore, the control device 20 executes such a control procedure to quickly determine the difference from the set oil type. In this case, when the control device 20 determines that the oil type is incorrect in step S14, it proceeds to step S15, where it quickly obtains the difference between the actual torque Tr and the water temperature estimated torque Tw, and executes the correction calculation of the target intake air amount Qt and the correction of the throttle opening ThO of the throttle valve 2b. In other words, the control device 20 obtains the difference between the water temperature estimated torque Tw and the actual torque Tr without executing the first learning control. Then, the control device 20 proceeds from step S15 to step S16, executes firing, and proceeds to step S11. This allows the actual torque Tr (the output exerted) to be quickly matched to the engine required torque ETq (the target output). In addition, since the first learning control is not executed, the calculation load of the control device 20 is also reduced.

If the control device 20 determines in step S7 that external charging is occurring (step S7 YES), the process proceeds to step S17 and changes the time of the first learning control. Specifically, the control device 20 lengthens the time of the first learning control. When external charging is occurring, the charging rate SOC of the drive battery 10 is high. This allows for a longer motoring (cranking) time, which in turn makes it easier to lengthen the time of the first learning control accordingly. This makes it easier to improve the accuracy of the first learning value. As a result, it is easier to quickly achieve the target output after the internal combustion engine 2 starts, while suppressing starting failures.

As described above, the present disclosure provides a control device 20 for an electric vehicle 1 that can easily achieve a target output quickly after the internal combustion engine 2 starts.

<Other embodiments>
Although the embodiment of the present disclosure has been described above, the present disclosure is not limited to the above embodiment, and various modifications are possible without departing from the gist of the invention. In particular, the multiple modifications described in this specification can be arbitrarily combined as necessary.

(a) In the above embodiment, a four-wheel drive plug-in hybrid vehicle has been described as an example, but the present disclosure is not limited thereto. The electric vehicle 1 may be a front-wheel drive hybrid vehicle or a plug-in hybrid vehicle. The electric vehicle 1 may also be a four-wheel drive hybrid vehicle.

(b) In the above embodiment, an example has been described in which the control device 20 executes all of the control procedures, but the present disclosure is not limited to this. A part of the control procedures of the control device 20 may be executed by the engine control device 2a.

1: Electric vehicle 2: Internal combustion engine 2b: Throttle valve 2f: Water temperature sensor (an example of a water temperature detection unit)
2h: Oil temperature sensor (an example of an oil temperature detection unit)
4: Generator (first rotating electric machine)
20: Control device 22: External charging device Ot: Oil temperature Wt: Water temperature

Claims (7)

A control device for an electric vehicle having an internal combustion engine including a throttle valve and a first rotating electric machine capable of driving the internal combustion engine,
execute a first learning control for learning an intake air amount at the start of the internal combustion engine based on a difference between a first output calculated as an output at the start of the internal combustion engine, which is a period until firing for starting the internal combustion engine is performed , which is estimated based on a water temperature of the internal combustion engine, and a second output which is an output of the internal combustion engine driven by the first rotating electric machine at the start of the internal combustion engine, when the first rotating electric machine drives the internal combustion engine to motor it;
controlling the throttle valve so as to obtain the intake air amount learned by the first learning control, and then performing fuel injection and firing for starting the internal combustion engine .
A control device for an electric vehicle. After the fluctuation in the engine speed or the engine output based on the motoring falls within a predetermined range, the first learning control is executed.
The control device for an electric vehicle according to claim 1. After the internal combustion engine has completely exploded, a second learning control is executed to learn the intake air amount based on a difference between a third output, in which a first learning value, which is a difference between the first output and the second output , is reflected in the first output, and the second output.
The control device for an electric vehicle according to claim 1 or 2 . The internal combustion engine includes a water temperature detection unit that detects a water temperature of the internal combustion engine, and an oil temperature detection unit that detects an oil temperature of the internal combustion engine,
the control device for the electric vehicle determines that the type of oil input to the internal combustion engine is different from the type of oil used in calculating the first output when the difference between the first output and the second output is equal to or greater than a predetermined output and the difference between the water temperature and the oil temperature is smaller than a predetermined temperature.
The control device for an electric vehicle according to any one of claims 1 to 3 . When it is determined that the oil types are different, the intake air amount is corrected based on a difference between the first output and the second output at the time of the determination.
The control device for an electric vehicle according to claim 4 . the electric vehicle has a drive battery and an external charging device that charges the drive battery from an external power supply of the electric vehicle,
the control device for the electric vehicle extends an execution time of the first learning control when the driving battery is charged from the external power supply.
The control device for an electric vehicle according to any one of claims 1 to 5 . the execution time of the first learning control is shortened as the driver required output required for the electric vehicle when the first rotating electric machine drives the internal combustion engine is higher.
The control device for an electric vehicle according to any one of claims 1 to 6 .