Hybrid vehicle control device

Abstract

To suppress delay of control of a motor generator in torque compensation control when a stop cylinder is switched through rotation control.SOLUTION: A control device 500 includes an engine control unit 110 and a motor control unit 130. The engine control unit 110 executes: stop control for stopping fuel supply to some cylinder of a plurality of cylinders of an engine 11 and supplying fuel to cylinders other than the some cylinder; and rotation control for switching a stop cylinder to which fuel supply is stopped. During the stop control, the motor control unit 130 executes torque compensation control. When switching the stop cylinder, if engine speed is a threshold value or lower, the engine control unit 110 executes interruption control for burning fuel in all cylinders and then, switches the stop cylinder to resume the stop control.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a control device for a hybrid vehicle. [Background technology]

[0002] Patent Document 1 discloses a control device for a hybrid vehicle that performs stop control to raise the temperature of an exhaust gas purification device while the engine is running. In this stop control, the control device stops fuel supply to some of the cylinders of the engine and supplies fuel to the cylinders other than the some of the cylinders. The control device also performs torque compensation control using a motor generator to suppress torque fluctuations caused by including cylinders to which fuel supply is stopped.

[0003] If fuel supply to a particular cylinder is stopped for a long period of time due to the stop control, the cylinder block may be distorted due to thermal imbalance, and the temperature distribution in the exhaust purification device exposed to the exhaust gas discharged from each cylinder may become uneven, and control based on the air-fuel ratio detected by the air-fuel ratio sensor may become unstable.

[0004] Therefore, in the above-described control device, rotation control is performed to switch the cylinders to which fuel supply is stopped during stop control so that the stop of fuel supply to a particular cylinder does not continue for too long.

[0005] The hybrid vehicle includes an engine control unit that controls the engine, and a motor control unit that controls the motor generator. The hybrid vehicle also includes a vehicle control unit as a control device that outputs control commands to the engine control unit and the motor control unit. These control units are connected to each other by communication lines and exchange information via CAN communication.

[0006] The stop control is performed by an engine control unit that controls the engine, and the torque compensation control is performed by a motor control unit that controls the motor. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent Publication No. 2021-60026 Summary of the Invention [Problem to be solved by the invention]

[0008] In the torque compensation control, the motor control unit receives information from the engine control unit indicating which cylinders are stopped, and based on that information, the motor control unit controls the motor generator in accordance with the torque fluctuations of the engine.

[0009] When switching between stopped cylinders using rotation control, if the ignition timing of the next stopped cylinder is close to the ignition timing of the current stopped cylinder, it may not be possible to control the motor generator in time even if information about the stopped cylinder is acquired and then controlled based on that information. As a result, the motor generator cannot be controlled at the appropriate timing, which may actually increase torque fluctuations. [Means for solving the problem]

[0010] The means for solving the above problems and their effects will be described below. A control device for a hybrid vehicle to solve the above problems includes an engine control unit that controls an engine, and a motor control unit that controls a motor generator. In this control device, the engine control unit executes a stop control that stops fuel supply to some of the cylinders of the engine and executes fuel supply to the cylinders other than the some of the cylinders, and a rotation control that switches the stopped cylinders to which fuel supply is stopped during the stop control. In addition, in this control device, the motor control unit executes a torque compensation control that compensates for a torque shortage caused by the inclusion of a stopped cylinder by the motor generator, based on information about the stopped cylinders acquired from the engine control unit through CAN communication, during the stop control.

[0011] In addition, in this control device, when the engine control unit changes the stopped cylinders by the rotation control, if the engine speed is equal to or lower than a threshold value, the engine control unit interrupts the stop control and executes interruption control in which fuel is burned in all cylinders, then changes the stopped cylinders and resumes the stop control, whereas if the engine speed is higher than the threshold value, the engine control unit changes the stopped cylinders while continuing the stop control without executing the interruption control.

[0012] According to the above configuration, when the engine rotation speed is equal to or lower than the threshold value and stop control is being performed while executing torque compensation control, when switching the stopped cylinders by rotation control, interruption control is performed and combustion is performed in all cylinders once. Then, from a state in which combustion is performed in all cylinders, stop control is resumed by switching the stopped cylinders. By inserting the interruption control in this way, a period is created in which it is not necessary to execute the torque compensation control. Therefore, the control of the motor generator in the torque compensation control can be executed in conjunction with the resumption of stop control by switching the stopped cylinders. In other words, according to the above configuration, when the stopped cylinders are switched by rotation control, it is possible to prevent the control of the motor generator in the torque compensation control from being delayed in time. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a schematic diagram showing the relationship between a control device for a hybrid vehicle and the hybrid vehicle controlled by the control device. [Diagram 2] FIG. 2 is a flowchart showing the flow of a series of processes in a routine related to the execution of stop control. [Diagram 3] FIG. 3 is a flowchart showing a series of processing steps in a routine for executing the torque compensation control. [Figure 4] FIG. 4 is a flowchart showing the flow of a series of processes in a routine related to rotation control. [Diagram 5] 5A and 5B are time charts showing switching of cylinders to be stopped when the engine speed is high, where Fig. 5(a) shows the transition of the cylinder stop flag, and Fig. 5(b) shows the transition of the cycle counter. [Figure 6] 6A and 6B are time charts showing switching of cylinders to be stopped when the engine speed is low, in which (a) shows the transition of the cylinder stop flag, and (b) shows the transition of the cycle counter. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, a control device 500, which is a control device for a hybrid vehicle according to one embodiment, will be described with reference to FIGS. <Vehicle 10 Configuration> First, the configuration of a vehicle 10 equipped with a control device 500 will be described with reference to Fig. 1. As shown in Fig. 1, the vehicle 10 includes an engine 11 and a second motor generator 32 as power sources. In other words, the vehicle 10 is a hybrid vehicle.

[0015] The engine 11 includes an intake passage 12 and an exhaust passage 21. In the example shown in FIG. 1, the engine 11 includes four cylinders. The intake passage 12 includes a throttle valve 13 for adjusting the flow rate of intake air flowing through the intake passage 12. The engine 11 includes a plurality of injectors 14 for injecting fuel during intake, one for each cylinder. The plurality of injectors 14 may be provided for each cylinder, or the number of injectors provided for each cylinder may differ. The engine 11 includes a plurality of spark plugs 15 for igniting a mixture of fuel and intake air by spark discharge, one for each cylinder. The plurality of spark plugs 15 may be provided for each cylinder, or the number of injectors provided for each cylinder may differ.

[0016] An upstream exhaust purification device 22 and a downstream exhaust purification device 23 are installed in an exhaust passage 21 of the engine 11. The downstream exhaust purification device 23 is provided downstream of the upstream exhaust purification device 22 in the exhaust passage 21. The upstream exhaust purification device 22 is a NOx storage type three-way catalyst. The downstream exhaust purification device 23 is a particulate filter that collects particulate matter in the exhaust gas and supports the three-way catalyst.

[0017] The second motor generator 32 is connected to a battery 50 via a power control unit 35. The second motor generator 32 is linked to driving wheels 40 via a reduction mechanism .

[0018] The engine 11 is also connected to drive wheels 40 via a power split mechanism 30 and a reduction gear mechanism 34. A first motor generator 31 is also connected to the power split mechanism 30. The first motor generator 31 is, for example, a three-phase AC motor generator. The power split mechanism 30 is a planetary gear mechanism, and can split the driving force of the engine 11 between the first motor generator 31 and the drive wheels 40.

[0019] The first motor generator 31 generates electricity by receiving driving force from the engine 11 and driving force from the drive wheels 40. The first motor generator 31 also serves as a starter that drives the crankshaft, which is the output shaft of the engine 11, when starting the engine 11. At that time, the first motor generator 31 functions as a motor that generates driving force in response to the supply of electric power from the battery 50.

[0020] The first motor generator 31 and the second motor generator 32 are connected to a battery 50 via a power control unit 35. AC power generated by the first motor generator 31 is converted to DC power by the power control unit 35 and charged into the battery 50. In other words, the power control unit 35 functions as an inverter.

[0021] Moreover, the DC power of the battery 50 is converted to AC by the power control unit 35 and supplied to the second motor generator 32. When the vehicle 10 is decelerated, the second motor generator 32 generates power by utilizing the driving force from the drive wheels 40. The generated power is then charged to the battery 50. That is, the vehicle 10 performs regenerative charging. At this time, the second motor generator 32 functions as a generator. The AC power generated by the second motor generator 32 is converted to DC by the power control unit 35 and charged to the battery 50.

[0022] When the first motor generator 31 is caused to function as a starter, the power control unit 35 converts the DC power of the battery 50 into AC power and supplies it to the first motor generator 31.

[0023] <Regarding the control device 500> The control device 500 controls the engine 11, the first motor generator 31, and the second motor generator 32. The control device 500 includes an engine control unit 110 that controls the engine 11. The control device 500 also includes a motor control unit 130 that controls the power control unit 35 to control the first motor generator 31 and the second motor generator 32. The control device 500 also includes a vehicle control unit 100 that is connected to the engine control unit 110 and the motor control unit 130 and supervises control of the vehicle 10. These control units are configured with a processing circuit and a memory that stores programs executed by the processing circuit, etc.

[0024] The control device 500 controls the engine 11, the first motor generator 31, and the second motor generator 32. In other words, the control device 500 controls the power train of the vehicle 10. Detection signals from sensors provided in various parts of the vehicle 10 are input to the control device 500.

[0025] Specifically, an accelerator position sensor 101, a brake sensor 102, and a vehicle speed sensor 103 are connected to the vehicle control unit 100. The accelerator position sensor 101 detects the accelerator opening. The brake sensor 102 detects the amount of brake operation. The vehicle speed sensor 103 detects the vehicle speed, which is the speed of the vehicle 10.

[0026] A crank position sensor 111 and a water temperature sensor 112 are connected to the engine control unit 110. The crank position sensor 111 outputs a crank angle signal each time the crankshaft rotates a certain angle. The engine control unit 110 calculates the rotation phase of the crankshaft and the engine rotation speed NE, which is the rotation speed of the crankshaft, based on the crank angle signal. The water temperature sensor 112 detects the engine cooling water temperature, which is the temperature of the cooling water for the engine 11.

[0027] An upstream air-fuel ratio sensor 113 is provided upstream of the upstream exhaust purification device 22 in the exhaust passage 21. The upstream air-fuel ratio sensor 113 is connected to the engine control unit 110. The upstream air-fuel ratio sensor 113 detects the air-fuel ratio of the exhaust gas introduced into the upstream exhaust purification device 22.

[0028] A downstream air-fuel ratio sensor 114 is disposed in a portion of the exhaust passage 21 that is downstream of the upstream exhaust purification device 22 and upstream of the downstream exhaust purification device 23. The downstream air-fuel ratio sensor 114 is also connected to the engine control unit 110. The downstream air-fuel ratio sensor 114 detects the air-fuel ratio of the exhaust gas that has passed through the upstream exhaust purification device 22.

[0029] The engine control unit 110 is also connected to a differential pressure sensor 115 which detects the differential pressure between the exhaust pressure in the portion of the exhaust passage 21 between the upstream exhaust purification device 22 and the downstream exhaust purification device 23, and the exhaust pressure in the portion downstream of the downstream exhaust purification device 23.

[0030] In addition, an upstream temperature sensor 116 that detects the temperature of the upstream exhaust purification device 22 and a downstream temperature sensor 117 that detects the temperature of the downstream exhaust purification device 23 are also connected to the engine control unit 110.

[0031] In addition, the current, voltage, and temperature of the battery 50 are input to the motor control unit 130 via the power control unit 35. The motor control unit 130 calculates a state of charge index value SOC, which is the ratio of the remaining charge to the charge capacity of the battery 50, based on the current, voltage, and temperature.

[0032] The engine control unit 110 and the motor control unit 130 are each connected to the vehicle control unit 100 via a communication line. The vehicle control unit 100, the motor control unit 130, and the engine control unit 110 mutually exchange and share information based on detection signals input from sensors via CAN communication and calculated information.

[0033] <Regarding control of vehicle 10> The vehicle 10 configured as described above can perform motor running in which the drive wheels 40 are driven using only the second motor generator 32 by using the power stored in the battery 50 to drive the second motor generator 32. In addition, the vehicle 10 can also perform hybrid running in which the drive wheels 40 are driven using both the engine 11 and the second motor generator 32.

[0034] The vehicle control unit 100 outputs the required power and required engine speed of the engine 11 to the engine control unit 110 based on the accelerator opening, the brake operation amount, the vehicle speed, and the state of charge index value SOC. It also outputs the required torque and target rotation speed for the first motor generator 31 and the second motor generator 32 to the motor control unit 130.

[0035] The engine control unit 110 controls the engine 11 to achieve the required power and required engine speed. The engine control unit 110 basically executes fuel injection control so that the air-fuel ratio in each cylinder of the engine 11 becomes the theoretical air-fuel ratio. The fuel injection and ignition in the engine 11 are executed in the following order: No. 1 cylinder #1, No. 3 cylinder #3, No. 4 cylinder #4, and No. 2 cylinder #2.

[0036] The motor control unit 130 controls the first motor generator 31 and the second motor generator 32 so as to realize the required torque and the target rotation speed. <About particulate filter regeneration> The vehicle 10 is equipped with a downstream exhaust purification device 23 in which a three-way catalyst is supported on a particulate filter. The amount Dpm of particulate matter deposited on the particulate filter increases with an increase in the driving process of the vehicle 10. The amount Dpm of deposition is more likely to increase as the environmental temperature decreases. Therefore, in the vehicle 10, when the amount Dpm of particulate matter deposited on the particulate filter increases to a certain level, it is necessary to burn the deposited particulate matter and regenerate the particulate filter. In this vehicle 10, the particulate filter is heated sufficiently, and oxygen is fed to the particulate filter to burn the particulate matter deposited on the particulate filter.

[0037] <About stop control> Hereinafter, the control for increasing the temperature of the particulate filter of the downstream side exhaust purification device 23 and burning the accumulated particulate matter to regenerate the particulate filter is referred to as stop control. In the stop control, the fuel supply to one of the four cylinders of the engine 11 is stopped, and the crankshaft is rotated by the torque generated by the combustion in the other cylinders. Then, air is sent into the exhaust passage 21 from the stopped cylinder to which the fuel supply is stopped.

[0038] Next, a routine for this stop control will be described with reference to Fig. 2. This routine shown in Fig. 2 is repeatedly executed by the engine control unit 110 at a predetermined control period while the engine 11 is operating.

[0039] As shown in FIG. 2, when this routine starts, the engine control unit 110 first acquires information such as the temperature of the downstream exhaust purification device 23 and the differential pressure detected by the differential pressure sensor 115 in the process of step S100.

[0040] Then, in the process of the next step S110, the engine control unit 110 calculates the amount of deposition Dpm of particulate matter in the particulate filter. Specifically, the engine control unit 110 calculates the amount of deposition Dpm based on the differential pressure detected by the differential pressure sensor 115. The more particulate matter is deposited in the particulate filter, the larger the differential pressure becomes. Therefore, the engine control unit 110 calculates a larger value as the amount of deposition Dpm as the differential pressure increases. Note that the amount of deposition Dpm may be calculated by estimating the amount of generation or amount of combustion of particulate matter based on information such as the amount of fuel injection, the air-fuel ratio, and the engine rotation speed NE.

[0041] After calculating the deposition amount Dpm in this way, the engine control unit 110 advances the process to step S120. In the process of step S120, the engine control unit 110 determines whether or not the cylinder stop flag F_fc is "0". The cylinder stop flag F_fc is a flag that indicates that stop control is being executed by being "1". The cylinder stop flag F_fc is "0" in the initial state.

[0042] When it is determined in the process of step S120 that the cylinder stop flag F_fc is "0" (step S120: YES), the engine control unit 110 advances the process to step S130. That is, when the stop control is not being executed, the engine control unit 110 determines whether or not the deposition amount Dpm is equal to or greater than a threshold value D1 in the process of step S130. The threshold value D1 is a threshold value for determining that regeneration of the particulate filter is necessary based on the deposition amount Dpm being equal to or greater than the threshold value D1. The magnitude of the threshold value D1 is set so that such a determination can be made based on the results of experiments or the like conducted in advance.

[0043] When it is determined in the process of step S130 that the deposition amount Dpm is equal to or greater than the threshold value D1 (step S130: YES), the engine control unit 110 advances the process to step S140. In the process of step S140, the engine control unit 110 determines whether or not the temperature Tpf of the particulate filter is less than the threshold value Tx. The engine control unit 110 performs the process of step S140 by regarding the temperature of the downstream side exhaust purification device 23 detected by the downstream side temperature sensor 117 as the temperature Tpf of the particulate filter. The threshold value Tx is set based on the temperature required for burning particulate matter, and is a threshold value for determining that it is necessary to execute stop control based on the temperature Tpf being less than the threshold value Tx. The magnitude of the threshold value Tx is set so that such a determination can be made based on the results of experiments or the like performed in advance.

[0044] When it is determined in the process of step S140 that the temperature Tpf of the particulate filter is lower than the threshold value Tx (step S140: YES), the engine control unit 110 advances the process to step S150.

[0045] In the process of step S150, the engine control unit 110 updates the cylinder stop flag F_fc to 1. Then, in the process of the next step S160, the engine control unit 110 starts stop control.

[0046] In the stop control, the engine control unit 110 sets the fuel injection amount of one cylinder to "0" to stop the fuel supply. Hereinafter, in the stop control, the cylinder to which the fuel supply is stopped is referred to as a stopped cylinder. Then, the engine control unit 110 allocates the amount of fuel that was supposed to be supplied to the stopped cylinder to the fuel injection amount of the cylinders other than the stopped cylinder. As a result, the fuel injection amount of the cylinders other than the stopped cylinder is increased.

[0047] After setting the fuel injection amount for each cylinder in this way, the engine control unit 110 executes fuel injection at the fuel injection timing for each cylinder. Note that in the stopped cylinders, fuel injection is not executed because the fuel injection amount is "0". The fuel injection amount for each cylinder is set in this way every time one cycle of fuel injection is completed. In other words, the fuel injection amount is updated every cycle according to the operating state at that time.

[0048] In the stop control, the engine control unit 110 stops the fuel supply to one cylinder in this way, and rotates the crankshaft with the torque generated by combustion in the cylinders other than the stopped cylinder.

[0049] As a result, air that has passed through the stopped cylinder and excess fuel supplied to the cylinders other than the stopped cylinder are introduced into the upstream side exhaust purification device 22 and the downstream side exhaust purification device 23. As a result, the fuel is oxidized by the action of the three-way catalyst in the upstream side exhaust purification device 22. Then, exhaust gas warmed by this reaction heat is introduced into the downstream side exhaust purification device 23, and the temperature Tpf of the particulate filter increases.

[0050] When the stop control is continued, if the temperature Tpf of the particulate filter becomes equal to or higher than the threshold value Ty, the engine control unit 110 reduces the fuel injection amount of the cylinders other than the stopped cylinder. The threshold value Ty is set to a temperature higher than the threshold value Tx. In this way, the engine control unit 110 continues to introduce air into the exhaust passage 21 while suppressing an excessive rise in the temperature Tpf. As a result, the particulate matter accumulated in the particulate filter is burned through the stop control, and the regeneration of the particulate filter progresses.

[0051] However, when it is determined in the process of step S130 that the deposition amount Dpm is less than the threshold value D1 (step S130: NO), the routine is terminated as it is. That is, in this case, it is not necessary to execute the stop control yet. Therefore, the engine control unit 110 terminates the routine as it is without executing the processes of steps S140 to S160.

[0052] Also, in the process of step S140, when it is determined that the temperature Tpf of the particulate filter is equal to or higher than the threshold value Tx (step S140: NO), the engine control unit 110 also ends this routine once. That is, in this case, the temperature Tpf is sufficiently high and there is no need to execute the stop control. Therefore, the engine control unit 110 ends this routine once without executing the processes of steps S150 and S160.

[0053] Once the stop control is started through the process of step S160, the engine control unit 110 basically continues to execute the stop control until the stop control is ended through the process of step S190, as described below. Note that the stop control also ends when the operation of the engine 11 is stopped.

[0054] While the stop control is being executed, the cylinder stop flag F_fc is set to 1. Therefore, in the process of step S120, it is determined that the cylinder stop flag F_fc is not 0 (step S120: NO).

[0055] If it is determined in the process of step S120 that the cylinder stop flag F_fc is not "0" (step S120: NO), the engine control unit 110 advances the process to step S170.

[0056] In the process of step S170, the engine control unit 110 judges whether the deposition amount Dpm is equal to or less than a threshold value D0. The threshold value D0 is a value smaller than the threshold value D1. The threshold value D0 is a threshold value for judging that the regeneration of the particulate filter has been sufficiently performed based on the deposition amount Dpm being equal to or less than the threshold value D0. The magnitude of the threshold value D0 is set so that such a judgment can be made based on the results of experiments or the like performed in advance.

[0057] In the process of step S170, when it is determined that the deposition amount Dpm is equal to or less than the threshold value D0 (step S170: YES), the engine control unit 110 advances the process to step S180. Then, in the process of step S180, the engine control unit 110 resets the cylinder stop flag F_fc to "0". Then, in the process of the next step S190, the engine control unit 110 ends the stop control. When the stop control is thus ended, the engine control unit 110 temporarily ends this series of routines.

[0058] On the other hand, when it is determined in the process of step S170 that the deposition amount Dpm is greater than the threshold value D0 (step S170: NO), the engine control unit 110 ends this routine as it is. That is, in this case, the engine control unit 110 continues the stop control without executing the processes of steps S180 and S190. Then, the engine control unit 110 ends this series of routines for the time being.

[0059] That is, when the engine control unit 110 starts the stop control, it continues the stop control until the deposition amount Dpm becomes equal to or less than the threshold value D0. Then, when the deposition amount Dpm becomes equal to or less than the threshold value D0, it ends the stop control and ends the regeneration of the particulate filter. As a result, fuel is supplied to all cylinders.

[0060] <Torque compensation control> Next, a routine related to the torque compensation control will be described with reference to Fig. 3. This routine is repeatedly executed at a predetermined control period by the motor control unit 130 while the control device 500 of the vehicle 10 is operating.

[0061] When this routine starts, the motor control unit 130 first determines in the process of step S200 whether or not the cylinder stop flag F_fc is 1. That is, in the process of step S200, the motor control unit 130 determines whether or not the stop control is being executed.

[0062] If it is determined in the process of step S200 that the cylinder stop flag F_fc is "1" (step S200: YES), the motor control unit 130 proceeds to the process of step S210. Then, in the process of step S210, the motor control unit 130 determines whether the engine speed NE is equal to or lower than the threshold value N1. Then, the motor control unit 130 proceeds to the process of step S220, and executes the torque compensation control in step S220.

[0063] When stop control is being executed, no energy is generated by combustion in the stopped cylinders, so that periodic fluctuations occur in the output torque of the engine 11. When the engine speed NE is high, the intervals between combustions in each cylinder are short, so that there is no effect from this torque fluctuation. However, when the engine speed NE is low, this torque fluctuation causes vibrations in the vehicle 10. In order to suppress such vibrations during stop control, the vehicle 10 executes torque compensation control that drives the second motor generator 32 to compensate for the torque shortage due to the stopped cylinders.

[0064] The threshold value N1 in step S210 is a threshold value for determining whether or not it is necessary to execute the torque compensation control. That is, the threshold value N1 is a threshold value for determining whether or not it is necessary to execute the torque compensation control to suppress vibrations based on the fact that the engine rotation speed NE is equal to or lower than the threshold value N1. The magnitude of the threshold value N1 is set so that such a determination can be made based on the results of experiments or the like conducted in advance.

[0065] In the torque compensation control process in step S220, the motor control unit 130 acquires information indicating which cylinders are to be stopped in the stop control through CAN communication. The motor control unit 130 also acquires information on the fuel injection amount, engine speed NE, and crank angle for each cylinder.

[0066] Based on this information, the motor control unit 130 sets the magnitude of the torque to be generated by the second motor generator 32 and the timing at which the torque is generated during torque compensation control. Then, the motor control unit 130 drives the second motor generator 32 in synchronization with the rotation of the crankshaft based on the crank angle signal.

[0067] Incidentally, when the deposition amount Dpm is large, the stop control is executed for a relatively long time. If fuel supply to a particular cylinder is stopped for a long time, the cylinder block of the engine 11 may be distorted due to thermal imbalance. Also, the temperature distribution in the upstream exhaust purification device 22 exposed to the exhaust gas discharged from each cylinder may become uneven. In addition, the air-fuel ratio detected by the upstream air-fuel ratio sensor 113 may vary, causing deviations in the control performed based on this air-fuel ratio.

[0068] Therefore, the control device 500 of the vehicle 10 executes a rotation control for switching the stopped cylinders so that the fuel supply to a particular cylinder is not stopped for too long. <About rotation control> A routine related to the rotation control will be described with reference to Fig. 4. This routine is repeatedly executed at a predetermined control period by the engine control unit 110 while the stop control is being executed.

[0069] When this routine is started, the engine control unit 110 first acquires the engine rotation speed NE in the process of step S300. Then, in the process of the next step S310, the engine control unit 110 increments the cycle counter Cc and the cumulative number counter Cn. The cycle counter Cc is a counter that indicates the number of driving cycles in a state in which fuel supply to any cylinder is stopped. The cycle counter Cc is reset to "0" when the stop control is completed. And, the cumulative number counter Cn is provided for each of the multiple cylinders of the engine 11. The cumulative number counter Cn is a counter that indicates the number of times that the corresponding cylinder has been stopped as a stopped cylinder and fuel supply has been stopped, that is, the cumulative number of times that fuel supply has been stopped.

[0070] In the process of step S310, the engine control unit 110 increments the cycle counter Cc and the cumulative number counter Cn corresponding to the stopped cylinder by one each time one cycle is completed.

[0071] Next, in the process of step S320, the engine control unit 110 judges whether the cycle counter Cc is equal to or greater than a threshold value Cc1. The threshold value Cc1 is a threshold value for determining whether or not to change the stopped cylinder. When the cycle counter Cc is equal to or greater than the threshold value Cc1, the engine control unit 110 changes the stopped cylinder. For example, the value is set to 50 cycles, or 100 revolutions of the crankshaft.

[0072] In the process of step S320, when it is determined that the cycle counter Cc is less than the threshold value Cc1 (step S320: NO), the engine control unit 110 does not change the stopped cylinder and ends this routine once.

[0073] On the other hand, if it is determined in the process of step S320 that the cycle counter Cc is equal to or greater than the threshold value Cc1 (step S320: YES), the engine control unit 110 proceeds to the process of step S330. Then, in the process of step S330, the engine control unit 110 determines the next cylinder to be stopped. Specifically, in the process of step S330, the engine control unit 110 determines the cylinder with the smallest value of the cumulative number counter Cn as the next cylinder to be stopped.

[0074] In the next step S340, the engine control unit 110 determines whether the engine speed NE is equal to or lower than a threshold value N1. The step S340 is a step of determining whether the torque compensation control is being executed based on the engine speed NE.

[0075] When it is determined in the process of step S340 that the engine rotation speed NE is higher than the threshold value N1 (step S340: NO), the engine control unit 110 resets the cycle counter Cc to "0" in the process of step S380. Then, the engine control unit 110 advances the process to step S370. In the process of step S370, the engine control unit 110 changes the stopped cylinder to the next stopped cylinder determined in step S330, and temporarily ends this series of processes. That is, when the torque compensation control is not being executed, the engine control unit 110 resets the cycle counter Cc and immediately switches the stopped cylinder. After switching the stopped cylinder in this way, the engine control unit 110 temporarily ends this routine.

[0076] On the other hand, when it is determined in the process of step S340 that the engine rotation speed NE is equal to or lower than the threshold value N1 (step S340: YES), the engine control unit 110 resets the cycle counter Cc to 0 in the process of step S350. Next, the engine control unit 110 proceeds to the process of step S360 and executes the interruption control.

[0077] The interruption control is a control for temporarily interrupting the stop control for stopping the fuel supply to the stopped cylinder. When the engine control unit 110 starts the interruption control, it sets the cylinder stop flag F_fc to "0". As a result, the engine control unit 110 interrupts the stop of the fuel supply to the stopped cylinder and the increase in the fuel injection amount by distributing the fuel injection amount to the cylinders other than the stopped cylinder, and performs normal operation in which combustion is performed in all cylinders. The engine control unit 110 continues the interruption control until at least one combustion is performed in all cylinders. Note that the control device 500 executes the interruption control for a predetermined number of cycles. For example, the engine control unit 110 executes the interruption control for two cycles, that is, until the crankshaft rotates four times, and then ends the interruption control. When ending the interruption control, the engine control unit 110 returns the cylinder stop flag F_fc to "1". When the interruption control ends, the engine control unit 110 advances the process to step S370.

[0078] Then, in the process of step S370, the engine control unit 110 changes the stopped cylinder to the next stopped cylinder determined in step S330, resumes the stop control, and temporarily ends this series of processes. That is, when the torque compensation control is being executed, the engine control unit 110 resets the cycle counter Cc, executes the interruption control, and then switches the stopped cylinder. Then, the engine control unit 110 temporarily ends this routine.

[0079] <Action of this embodiment> Next, the operation of the control device 500 will be described with reference to Fig. 5 and Fig. 6. Fig. 5 and Fig. 6 are time charts showing the transition of the cylinder stop flag F_fc and the cycle counter Cc when the stopped cylinder is changed. Fig. 5 is a time chart when the engine speed NE is higher than the threshold value N1 and the torque compensation control is not executed during the stop control. On the other hand, Fig. 6 is a time chart when the engine speed NE is equal to or lower than the threshold value N1 and the torque compensation control is executed together with the stop control.

[0080] First, an example of a case where the torque compensation control is not executed during the stop control will be described with reference to FIG. As shown in Fig. 5(a), when the cylinder stop flag F_fc is changed to "1" at time t1 (step S150), the stop control is started (step S160). As a result, the routine described with reference to Fig. 4 is started from time t1, and as shown in Fig. 5(b), the increment of the cycle counter Cc is started (step S310).

[0081] As shown in FIG. 5(b), when the cycle counter Cc becomes equal to or greater than the threshold value Cc1 at time t2 (step S320: YES), the cylinder with the smallest cumulative number counter Cn is determined to be the next cylinder to be stopped (step S330). In this case, the engine speed NE is higher than the threshold value N1 (step S340: NO), and torque compensation control is not being executed. Therefore, when the cycle counter Cc is reset to "0" (step S380), the stopped cylinder is immediately changed (step S370). That is, in this case, the interruption control is not executed, and the stopped cylinder is changed while the stop control is continued. Therefore, as shown in FIG. 5(a), the cylinder stop flag F_fc remains at "1".

[0082] At time t4, when the deposition amount Dpm becomes equal to or less than the threshold value D0 (step S170: YES), the cylinder stop flag F_fc is reset to "0" (step S180) as shown in Fig. 5(a), and the stop control ends (step S190). Accordingly, the cycle counter Cc is also reset to "0" as shown in Fig. 5(b).

[0083] In this manner, when the engine speed NE is higher than the threshold value N1, the engine control unit 110 does not execute the interruption control, but changes the stopped cylinder while continuing the stop control. Next, an example in which torque compensation control is executed together with stop control will be described with reference to FIG.

[0084] As shown in Fig. 6(a), when the cylinder stop flag F_fc is changed to "1" at time t11 (step S150), the stop control is started (step S160). As a result, the routine described with reference to Fig. 4 is started from time t11, and as shown in Fig. 6(b), the cycle counter Cc starts to be incremented (step S310).

[0085] As shown in FIG. 6(b), when the cycle counter Cc becomes equal to or greater than the threshold value Cc1 at time t12 (step S320: YES), the cylinder with the smallest cumulative number counter Cn is determined to be the next cylinder to be stopped (step S330). In this case, the engine speed NE is equal to or less than the threshold value N1 (step S340: YES), and torque compensation control is being executed. Therefore, when the cycle counter Cc is reset to "0" (step S350), interruption control is executed (step S360). As a result, as shown in FIG. 6(a), the cylinder stop flag F_fc is reset to "0", and the stop control is interrupted.

[0086] When the interruption process ends at time t13, the cylinder stop flag F_fc is updated to "1" as shown in Fig. 6(a), the stopped cylinder is changed, and the stop control is resumed (step S370). As a result, the increment of the cycle counter Cc is also resumed as shown in Fig. 6(b).

[0087] At time t14, when the deposition amount Dpm becomes equal to or less than the threshold value D0 (step S170: YES), the cylinder stop flag F_fc is reset to "0" (step S180) as shown in Fig. 6(a), and the stop control ends (step S190). Accordingly, the cycle counter Cc is also reset to "0" as shown in Fig. 6(b).

[0088] In this way, when the engine control unit 110 is executing the torque compensation control, it interrupts the stop control and executes the interruption control in which fuel is burned in all cylinders. After executing the interruption control, it changes the stopped cylinders and resumes the stop control.

[0089] In the torque compensation control, the motor control unit 130 receives information indicating which cylinder is stopped from the engine control unit 110 via CAN communication. Then, the motor control unit 130 controls the second motor generator 32 in accordance with the torque fluctuation of the engine 11 based on the information.

[0090] When switching the cylinders to be stopped by rotation control, it may not be possible to control the second motor generator 32 based on information about the stopped cylinders after obtaining the information, in time. For example, when the first cylinder #1 is set as the stopped cylinder and stop control is being performed, the third cylinder #3 may be determined as the next cylinder to be stopped. The third cylinder #3 is the cylinder that is ignited after the first cylinder #1. In this case, the ignition timing of the next stopped cylinder and the ignition timing of the current stopped cylinder are very close. Therefore, it may not be possible to control the second motor generator 32 based on the information about the stopped cylinders after the cylinders to be stopped are determined in time. As a result, it may not be possible to control the second motor generator 32 at the appropriate timing, which may actually promote torque fluctuation.

[0091] In contrast, according to the above-described control device 500, when the stop control is being performed while the torque compensation control is being performed, the interruption control is performed when switching the stopped cylinders by the rotation control, and combustion is performed in all cylinders once. Then, from the state in which combustion is performed in all cylinders, the stop control is resumed by switching the stopped cylinders. By inserting the interruption control in this way, a period occurs after the next stopped cylinder is determined during which it is not necessary to perform the torque compensation control. Therefore, before the stop control is resumed, information on the next stopped cylinder is obtained, and the control of the second motor generator 32 in the torque compensation control can be performed in accordance with the resumption of the stop control by switching the stopped cylinders.

[0092] <Effects of this embodiment> (1) The control of the second motor-generator 32 in the torque compensation control can be executed in accordance with the resumption of the stop control by switching the stopped cylinders. That is, the control device 500 can prevent the control of the second motor-generator 32 in the torque compensation control from being delayed when the stopped cylinders are switched by the rotation control.

[0093] (2) Since the stopped cylinders are switched by the rotation control, it is possible to suppress the occurrence of distortion due to thermal imbalance in the cylinder block. In addition, it is possible to suppress the occurrence of uneven temperature distribution in the upstream exhaust purification device 22 exposed to the exhaust gas discharged from each cylinder. It is possible to suppress the occurrence of deviations in the control based on the air-fuel ratio detected by the upstream air-fuel ratio sensor 113.

[0094] <Example of change> This embodiment can be modified as follows: This embodiment and the following modifications can be combined with each other to the extent that there is no technical contradiction.

[0095] In the above example, the cylinder with the smallest cumulative number of times counter Cn is selected as the next cylinder to be stopped. However, in the rotation control, the cylinder with the shortest cumulative stopped time, which is the accumulated time during which fuel supply is stopped as a stopped cylinder, may be selected as the next cylinder to be stopped.

[0096] In the above example, the number of cycles during which stop control is being executed is counted by the cycle counter Cc, and the stopped cylinders are changed or interruption control is executed when the cycle counter Cc becomes equal to or greater than a threshold value Cc1. However, instead of counting the number of cycles, the time during which stop control is being executed may be measured, and when a certain time is reached, the stopped cylinders may be changed or interruption control may be executed.

[0097] Although the engine 11 of the vehicle 10 is an in-line four-cylinder engine having four cylinders, the present invention is not limited to this. In other words, the engine 11 is not limited to a four-cylinder engine. The engine 11 may also be a V-type engine, a horizontally opposed engine, or a W-type engine in which an exhaust purification device is provided for each bank. In this case, the stop control is preferably configured so that fuel supply to at least one cylinder in each bank is stopped during one cycle. This makes it possible to feed sufficient oxygen to the exhaust purification device of each bank of a V-type engine, etc.

[0098] An example has been shown in which the upstream side exhaust purification device 22 and the downstream side exhaust purification device 23 are provided, and the downstream side exhaust purification device 23 is a particulate filter. The configuration of the exhaust purification system is not limited to this configuration. A configuration similar to that of the above embodiment can be applied to any control device that controls a vehicle equipped with at least an engine equipped with a particulate filter.

[0099] The configuration of the powertrain in the vehicle 10 is not limited to the configuration illustrated in Fig. 1. As long as the control device controls the vehicle and is capable of executing torque compensation control by the motor, the same configuration as in the above embodiment can be applied.

[0100] The control device 500 includes an engine control unit 110, a motor control unit 130, and a vehicle control unit 100. These control units may be configured as one or more processors that execute various processes according to a computer program (software). These control units may also be configured as one or more dedicated hardware circuits, such as an application specific integrated circuit (ASIC), that executes at least a part of the various processes. These control units may also be configured as a circuit including a combination of these. The processor includes a CPU and memory, such as a RAM and a ROM, and the memory stores program code or instructions configured to cause the CPU to execute processes. The memory, i.e., computer-readable medium, includes any available medium that can be accessed by a general-purpose or special-purpose computer. [Explanation of symbols]

[0101] 10. Vehicle 11…Engine 12…Intake passage 13...Throttle valve 14…Injector 15…Spark plug 21...Exhaust passage 22...Upstream exhaust purification device 23...Downstream exhaust purification device 30…Power splitting mechanism 31…First motor generator 32…Second motor generator 35...Power control unit 40…Drive wheel 50…Battery 100...Vehicle control unit 110…Engine control unit 130...Motor control unit 500...Control device

Claims

[Claim 1] The vehicle includes an engine control unit that controls an engine, and a motor control unit that controls a motor generator. the engine control unit executes a stop control for stopping fuel supply to some of the cylinders among a plurality of cylinders of the engine and executing fuel supply to the cylinders other than the some of the cylinders, and a rotation control for switching the stopped cylinders to which fuel supply is stopped in the stop control, a control device for a hybrid vehicle, the control device executing a torque compensation control, during the stop control, for compensating for a torque shortage caused by the inclusion of a stopped cylinder, by the motor generator, based on information about the stopped cylinder obtained from the engine control unit through CAN communication; A control device for a hybrid vehicle, in which, when the engine control unit changes the stopped cylinders through the rotation control, if the engine rotation speed is below a threshold value, the engine control unit interrupts the stop control and executes interruption control in which fuel is burned in all cylinders, then changes the stopped cylinders and resumes the stop control, and if the engine rotation speed is higher than the threshold value, the control unit changes the stopped cylinders while continuing the stop control without executing the interruption control.

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