JP7768049B2 - Hybrid vehicle control device - Google Patents

Description

The present invention relates to a control device for a hybrid vehicle.

Patent Document 1 describes a hybrid vehicle equipped with an internal combustion engine and an electric motor as power sources. In this hybrid vehicle, torque control of the electric motor is performed in accordance with the calculated estimated torque of the internal combustion engine. Here, in this hybrid vehicle, an smoothing process using an smoothing time constant is performed when calculating the estimated torque. Furthermore, different values of the smoothing time constant are set for the supercharging region and the non-supercharging region.

Japanese Patent Application Laid-Open No. 2020-152250

In hybrid vehicles, a stop process may be performed to stop combustion in some of the multiple cylinders in the internal combustion engine. When the stop process is performed, the engine torque in the cylinders where combustion has stopped decreases, causing the engine torque output from the internal combustion engine to oscillate. As a result, these oscillation components are reflected in the estimated torque of the internal combustion engine, causing the estimated torque to oscillate as well. When the estimated torque oscillates, the torque of the electric motor, which is adjusted according to the estimated torque, also oscillates, which could result in increased vehicle vibration.

A hybrid vehicle control device that solves the above problem is applied to a hybrid vehicle in which the rotating shaft of a rotating electric machine is connected to the crankshaft of an internal combustion engine with multiple cylinders. This control device executes a stop process that stops combustion in some of the cylinders of the internal combustion engine, a process that calculates an estimated torque of the internal combustion engine that has been smoothed using an smoothing time constant, a process that adjusts the torque output from the rotating electric machine in accordance with the estimated torque, and a process that sets the smoothing time constant to a larger value while the stop process is being executed than when the stop process is not being executed.

With this configuration, when the above-mentioned stop processing is performed, the smoothing time constant used to calculate the estimated torque is increased. This reduces vibrations in the estimated torque while the stop processing is being performed. This also reduces vibrations in the torque of the rotating electrical machine, which is adjusted according to the estimated torque, thereby suppressing vehicle vibrations.

1 is a diagram showing the configuration of a drive system and a control device for a vehicle according to an embodiment; 4 is a flowchart showing a procedure of a process executed by the control device according to the embodiment. 4 is a flowchart showing a procedure of a process executed by the control device according to the embodiment. 4 is a flowchart showing a procedure of a process executed by the control device according to the embodiment.

Hereinafter, a specific embodiment of a control device for a hybrid vehicle will be described.
<Configuration of vehicle drive system and control device>
As shown in FIG. 1, an internal combustion engine 10 mounted on a vehicle VC has, for example, four cylinders #1 to #4.

A throttle valve 14 is provided in the intake passage 12 of the internal combustion engine 10. A port injection valve 16 that injects fuel into the intake port 12a is provided in the downstream portion of the intake passage 12.

Air drawn into the intake passage 12 and fuel injected from the port injection valve 16 flow into the combustion chamber 20 when the intake valve 18 opens. Fuel is injected into the combustion chamber 20 from the in-cylinder injection valve 22. The air-fuel mixture in the combustion chamber 20 is then combusted by the spark discharge of the ignition device 24. The combustion energy generated at this time is converted into rotational energy of the crankshaft 26.

When the exhaust valve 28 opens, the air-fuel mixture burned in the combustion chamber 20 is discharged as exhaust gas into the exhaust passage 30. The exhaust passage 30 is equipped with a three-way catalyst 32 with oxygen storage capacity and a gasoline particulate filter (GPF 34). The GPF 34 is a filter that traps PM and supports a three-way catalyst.

The crankshaft 26 is mechanically connected to the carrier C of the planetary gear mechanism 50, which constitutes the power split device. The sun gear S of the planetary gear mechanism 50 is mechanically connected to the rotating shaft 52a of the first motor-generator 52, which is a rotating electric machine. The ring gear R of the planetary gear mechanism 50 is mechanically connected to the rotating shaft 54a of the second motor-generator 54, which is also a rotating electric machine, and the drive wheels 60. A hydraulic transmission 100 is provided on the power transmission path between the rotating shaft 54a of the second motor-generator 54 and the drive wheels 60.

An AC voltage is applied to the terminals of the first motor generator 52 by a first inverter 56. An AC voltage is applied to the terminals of the second motor generator 54 by a second inverter 58. Both the first inverter 56 and the second inverter 58 are power conversion circuits that convert the terminal voltage of a battery 59, which serves as a DC voltage source, into an AC voltage and output it.

The control device 70 operates the operating parts of the internal combustion engine 10, such as the throttle valve 14, port injection valve 16, in-cylinder injection valve 22, and ignition device 24, to control the torque, exhaust gas component ratio, and other control variables of the internal combustion engine 10 as the control target.

The control device 70 also operates the first inverter 56 to control the torque, which is the control variable of the first motor generator 52, which is the control object. The control device 70 also operates the second inverter 58 to control the torque, which is the control variable of the second motor generator 54, which is the control object. The control device 70 also operates the hydraulic mechanism of the transmission 100 to control the gear ratio of the transmission 100, which is the control object.

Figure 1 shows the operation signals MS1 to MS7 for the throttle valve 14, port injection valve 16, in-cylinder injection valve 22, ignition device 24, first inverter 56, second inverter 58, and transmission 100.

To control the control variables of the internal combustion engine 10, the control device 70 references the intake air volume Ga detected by the air flow meter 80 and the output signal Scr of the crank angle sensor 82. The control device 70 also references the water temperature THW detected by the water temperature sensor 84 and the output signal Sp of the output rotation angle sensor 86, which detects the rotation angle of the ring gear R. The control device 70 also references the temperature Tb of the battery 59 detected by the temperature sensor 87, the charge/discharge current I of the battery 59 detected by the current sensor 88, and the terminal voltage Vb of the battery 59 detected by the voltage sensor 89. To control the control variables of the first motor-generator 52, the control device 70 references the output signal Sm1 of the first rotation angle sensor 90, which detects the rotation angle of the first motor-generator 52. The control device 70 calculates a first rotation speed Nmg1, which is the rotation speed of the rotating shaft 52a of the first motor-generator 52, based on the output signal Sm1. In addition, to control the control amount of the second motor-generator 54, the control device 70 references the output signal Sm2 of the second rotation angle sensor 92, which detects the rotation angle of the second motor-generator 54. The control device 70 calculates the second rotation speed Nmg2, which is the rotation speed of the rotating shaft 54a of the second motor-generator 54, based on the output signal Sm2. The control device 70 also references the accelerator operation amount ACCP, which is the amount of depression of the accelerator pedal, detected by the accelerator sensor 94.

The control device 70 includes a CPU 72, ROM 74, peripheral circuits 76, and communication lines 78. The CPU 72, ROM 74, and peripheral circuits 76 are capable of communicating with each other via the communication lines 78. The peripheral circuits 76 include circuits that generate clock signals that regulate internal operation, power supply circuits, reset circuits, and the like. The control device 70 controls the control variables by having the CPU 72 execute programs stored in the ROM 74.

The following describes the processes executed by the control system shown in Figure 1, including the regeneration process of the GPF 34, the processes related to the operation of the motor generator and internal combustion engine, and the process for prohibiting the regeneration process.

<Recycling of GPF>
The playback process is shown in Fig. 2. The process shown in Fig. 2 is realized by the CPU 72 repeatedly executing a program stored in the ROM 74, for example, at a predetermined interval. In the following description, the step number of each process is represented by a number preceded by "S."

In the series of processes shown in FIG. 2, the CPU 72 first acquires the engine speed NE, charging efficiency η, and water temperature THW (S10). The engine speed NE is calculated by the CPU 72 based on the output signal Scr. The charging efficiency η is calculated by the CPU 72 based on the engine speed NE and the intake air amount Ga.

Next, the CPU 72 calculates an update amount ΔDPM for the accumulation amount DPM based on the engine speed NE, charging efficiency η, and water temperature THW (S12). Here, the accumulation amount DPM is the amount of PM trapped in the GPF 34. Specifically, the CPU 72 calculates the amount of PM in the exhaust gas discharged into the exhaust passage 30 based on the engine speed NE, charging efficiency η, and water temperature THW. The CPU 72 also calculates the temperature of the GPF 34 based on the engine speed NE and charging efficiency η. The CPU 72 then calculates the update amount ΔDPM based on the amount of PM in the exhaust gas and the temperature of the GPF 34. Note that when performing the processing of S20 described below, the temperature of the GPF 34 and the update amount ΔDPM can be calculated based on the increase coefficient K.

Next, the CPU 72 updates the accumulation amount DPM in accordance with the update amount ΔDPM (S14).
Next, the CPU 72 determines whether or not the execution flag Fc is 1 (S16). When the execution flag Fc is 1, this indicates that the regeneration process for burning and removing PM from the GPF 34 is being executed, and when the execution flag Fc is 0, this indicates that the regeneration process is not being executed.

If the CPU 72 determines that the execution flag Fc is "0" (S16: NO), it determines whether the accumulation amount DPM is equal to or greater than the regeneration execution value DPMH (S18). The regeneration execution value DPMH is set to a value at which the amount of PM trapped by the GPF 34 is large and it is desirable to remove the PM.

If the CPU 72 determines that the accumulation amount DPM is equal to or greater than the regeneration execution value DPMH (S18: YES), it executes the regeneration process and sets the execution flag Fc to "1" (S20).

In this embodiment, the CPU 72 executes a regeneration process to stop combustion in some cylinders of the internal combustion engine 10 by stopping fuel injection from the port injection valve 16 and the in-cylinder injection valve 22 of cylinder #1. In addition, in conjunction with this process, the CPU 72 executes a process to make the air-fuel ratio of the mixture in the combustion chamber 20 of cylinders #2, #3, and #4 richer than the stoichiometric air-fuel ratio. These processes are, first, a process to raise the temperature of the three-way catalyst 32. That is, by discharging oxygen and unburned fuel into the exhaust passage 30, the unburned fuel is oxidized in the three-way catalyst 32, thereby raising the temperature of the three-way catalyst 32. Second, they are a process to raise the temperature of the GPF 34 and supply oxygen to the heated GPF 34 to oxidize and remove the PM trapped by the GPF 34. That is, when the temperature of the three-way catalyst 32 becomes high, the high-temperature exhaust gas flows into the GPF 34, raising the temperature of the GPF 34. Then, oxygen flows into the heated GPF 34, oxidizing and removing the PM trapped by the GPF 34.

Specifically, the CPU 72 assigns "0" to the required injection amount Qd for the port injection valve 16 and in-cylinder injection valve 22 of cylinder #1. Meanwhile, the CPU 72 assigns the value obtained by multiplying the base injection amount Qb by the increase coefficient K to the required injection amount Qd for cylinders #2, #3, and #4. The base injection amount Qb is the injection amount required to make the air-fuel ratio of the mixture the stoichiometric air-fuel ratio. The CPU 72 calculates the base injection amount Qb by multiplying the charging efficiency η by a predetermined coefficient.

The CPU 72 sets the increase coefficient K so that the amount of unburned fuel in the exhaust gas discharged into the exhaust passage 30 from cylinders #2, #3, and #4 is equal to or less than the amount that reacts just right with the oxygen discharged from cylinder #1. Specifically, in the early stages of the regeneration process of the GPF 34, the CPU 72 sets the air-fuel ratio of the mixture in cylinders #2, #3, and #4 to a value as close as possible to the amount that reacts just right, in order to quickly raise the temperature of the three-way catalyst 32.

On the other hand, if the CPU 72 determines in the processing of S16 that the execution flag Fc is "1" (S16: YES), it determines whether the accumulation amount DPM is equal to or less than the stop threshold DPML (S22). The stop threshold DPML is set to a value at which the amount of PM trapped in the GPF 34 becomes small enough to allow the regeneration process to be stopped.

When the CPU 72 determines that the accumulation amount DPM is greater than the stop threshold value DPML (S22: NO), the CPU 72 continues the process of S20, that is, the regeneration process.
On the other hand, when it is determined that the accumulation amount DPM is equal to or less than the stop threshold value DPML (S22: YES), the CPU 72 stops the process of S20 and sets the execution flag Fc to "0" (S28).

When the CPU 72 has completed the process of S20 or S28, or when a negative determination is made in the process of S18, the CPU 72 temporarily ends the series of processes shown in FIG.
<Processing related to operation of the motor generator and the internal combustion engine>
The procedure for the process relating to the operation of the motor generator and the internal combustion engine is shown in Fig. 3. The process shown in Fig. 3 is realized by the CPU 72 repeatedly executing a program stored in the ROM 74, for example, at a predetermined interval.

In the series of processes shown in FIG. 3, the CPU 72 first acquires the accelerator operation amount ACCP and the output side rotation speed Np (S40). The output side rotation speed Np is the rotation speed of the ring gear R. In other words, it is a variable that indicates the vehicle speed. The output side rotation speed Np is calculated by the CPU 72 based on the output signal Sp.

The CPU 72 calculates a required drive torque Tp*, which is the torque required for the drive wheels 60, based on the accelerator operation amount ACCP and the output side rotation speed Np (S42).
Next, the CPU 72 substitutes the product of the required drive torque Tp* and the output side rotation speed Np into the running power Pp* (S44).

Next, the CPU 72 calculates the required charge/discharge power Pbatt* of the battery 59 based on the charging rate SOC of the battery 59 (S46). The required charge/discharge power Pbatt* is positive when discharging. More specifically, when the charging rate SOC is below a predetermined value, the CPU 72 sets the required charge/discharge power Pbatt* to a negative value in order to charge the battery 59. The charging rate SOC is calculated by the CPU 72 based on the charging/discharging current I and the terminal voltage Vb.

Next, the CPU 72 subtracts the product of the required charge/discharge power Pbatt* and the conversion efficiency Kef from the running power Pp*, and assigns the result to the required engine power Pe* (S48).
Next, the CPU 72 calculates the target engine rotation speed NE* and the required engine torque Te* (S50).

The target engine speed NE* is a target value for the engine speed NE. The CPU 72 first calculates the target engine speed NE*, for example, that allows the internal combustion engine 10 to operate efficiently, based on the required engine power Pe*. This can be achieved by having the CPU 72 perform map calculations to determine the target engine speed NE*, with map data pre-stored in the ROM 74. Here, the map data is data in which the required engine power Pe* is an input variable and the target engine speed NE* is an output variable. Incidentally, map data is a set of data consisting of discrete values of input variables and values of output variables corresponding to each of the input variable values. Furthermore, map calculations may be performed by processing in which, if the value of an input variable matches one of the input variable values in the map data, the value of the output variable in the corresponding map data is used as the calculation result. Furthermore, if the value of an input variable does not match any of the input variable values in the map data, map calculations may be performed by processing in which the value obtained by interpolating the values of multiple output variables included in the map data is used as the calculation result.

The CPU 72 then divides the required engine output Pe* by the target engine speed NE* and assigns the result to the required engine torque Te*. The CPU 72 then controls the opening of the throttle valve 14 to set the torque of the internal combustion engine 10 to the required engine torque Te*.

Next, the CPU 72 calculates the target first rotation speed Nmg1* (S52). The target first rotation speed Nmg1* is a target value for the first rotation speed Nmg1, which is the rotation speed of the rotating shaft 52a of the first motor-generator 52. More specifically, the target first rotation speed Nmg1* is the first rotation speed Nmg1 when the engine rotation speed NE becomes the target engine rotation speed NE*. The CPU 72 calculates the target first rotation speed Nmg1* based on the target engine rotation speed NE* and the output side rotation speed Np using the following equation (1):

Nmg1*=[{1/(1+ρ)}・Np-NE*]/{ρ/(1+ρ)}...(1)
However, the planetary gear ratio ρ in the above formula is a value obtained by dividing the number of teeth of the sun gear S by the number of teeth of the ring gear R.

Next, the CPU 72 calculates the required first torque Tmg1* (S54). The required first torque Tmg1* is the torque required for the first motor-generator 52. More specifically, the required first torque Tmg1* is the torque of the first motor-generator 52 required to set the first rotation speed Nmg1 to the target first rotation speed Nmg1*.

The CPU 72 calculates the required first torque Tmg1* as the sum of an open-loop term and a feedback term. Here, the open-loop term is a value obtained by "{-ρ/(1+ρ)}·Te*." Note that "-ρ/(1+ρ)" is a coefficient that converts the torque of the carrier C to the torque of the sun gear S. Meanwhile, the feedback term is a manipulated variable for feedback control of the first rotational speed Nmg1. The feedback term is the sum of the output value of the proportional element and the output value of the integral element. The output value of the proportional element is calculated by multiplying the error err1, which is the value obtained by subtracting the first rotational speed Nmg1 from the target first rotational speed Nmg1*, by the proportional gain Kp. The output value of the integral element is the integrated value of the error err1 multiplied by the integral gain Ki. The CPU 72 controls the drive of the first motor-generator 52 so as to obtain the required first torque Tmg1*.

Next, the CPU 72 calculates the required second torque base value Tmg2b* (S56). This required second torque base value Tmg2b* is calculated as follows: First, the CPU 72 multiplies "1/(1 + ρ)" by the estimated torque Tee and assigns the result to the direct torque Ted. Here, "1/(1 + ρ)" is a coefficient used to convert the torque of the carrier C into the torque of the ring gear R.

The estimated torque Tee is an estimate of the torque output by the internal combustion engine 10, and is calculated by the CPU 72 at predetermined intervals in a process separate from this process. This estimated torque Tee is a value obtained by smoothing the estimated torque base value Tee, calculated using the following equation (2), with an smoothing time constant N. In this smoothing process, the larger the value of the smoothing time constant N, the smaller the amount of change in the estimated torque Tee relative to the amount of change in the estimated torque base value Tee. In other words, the larger the value of the smoothing time constant N, the more gradual the responsiveness of the estimated torque Tee to changes in the estimated torque base value Tee. The smoothing time constant N is variably set in the process shown in Figure 4, which will be described later.

The direct torque Ted is the torque applied from the internal combustion engine 10 to the ring gear R. The CPU 72 then calculates the required second torque base value Tmg2b* by subtracting the direct torque Ted from the required drive torque Tp*. Here, the value obtained by subtracting the direct torque Ted from the required drive torque Tp* represents the shortfall in the output of the ring gear R when the torque of the drive wheels 60 is set to the required drive torque Tp*.

Next, the CPU 72 determines whether the regeneration process execution flag Fc is "1" (S58).
When it is determined that the execution flag Fc is "1" (S58: YES), the CPU 72 calculates the second superimposed torque ΔTmg2* (S38). The second superimposed torque ΔTmg2* is a torque for suppressing rotation fluctuations of the crankshaft 26 that accompany the regeneration process. The CPU 72 variably sets the second superimposed torque ΔTmg2* based on the engine rotation speed NE, the required engine torque Te*, and the second rotation speed Nmg2. The parameters that are variably set here are the phase, magnitude, and waveform of the second superimposed torque ΔTmg2*.

Next, the CPU 72 adds the second superimposed torque ΔTmg2* to the required second torque base value Tmg2b* and assigns the result to the required second torque Tmg2* (S62). The CPU 72 then controls the drive of the second motor-generator 54 so that the required second torque Tmg2* is obtained. The processes of S58, S60, and S62 are compensation processes in which, when stop processing is executed, the second motor-generator 54 generates torque to compensate for fluctuations in the rotation of the crankshaft 26 due to a decrease in torque of the internal combustion engine 10 caused by the cessation of combustion in some cylinders.

If it is determined in the processing of S58 above that the execution flag Fc is not "1" (S58: Y/N), the CPU 72 assigns the required second torque base value Tmg2b* to the required second torque Tmg2* (S64). The CPU 72 then controls the drive of the second motor-generator 54 so as to obtain the required second torque Tmg2*.

When the CPU 72 completes the processing of S62 or S64, it temporarily ends the series of processing steps shown in FIG.
<Setting process of the smoothing time constant>
When the stop process is executed as a result of the execution of the regeneration process, the engine torque output from the internal combustion engine 10 begins to oscillate at a high frequency. Here, the values used to calculate the estimated torque base value Teeb contain errors. Furthermore, communication delays occur between the sensor and the control device 70, making it difficult to accurately estimate the engine torque that oscillates at a high frequency.

Furthermore, when engine torque oscillates at a high frequency, the estimated engine torque also becomes a high frequency. When the estimated engine torque becomes a high frequency, the required second torque Tmg2* calculated based on the estimated engine torque also becomes a high frequency command value. However, it is difficult from a hardware perspective to actually output torque corresponding to such a high frequency command value from the second motor generator 54.

For these reasons, when the stop process is being executed, it becomes difficult to ensure an accurate driving force corresponding to the engine torque, which vibrates at high frequency, and there is a risk that vehicle vibration will occur.
Therefore, in this embodiment, the above-mentioned smoothing time constant N is appropriately set to suppress the vibration of the estimated torque Tee, thereby suppressing the occurrence of vehicle vibration.

Figure 4 shows the procedure for setting the smoothing time constant N. The process shown in Figure 4 is realized by the CPU 72 repeatedly executing a program stored in ROM 74 at predetermined intervals.

In the series of processes shown in FIG. 4, the CPU 72 first determines whether the regeneration process execution flag Fc is "1" (S100).
When the execution flag Fc is determined to be "1" (S100: YES), the CPU 72 assigns a second constant N2 to the smoothing time constant N (S120). In this embodiment, a first constant N1 and a second constant N2 are preset as values to be assigned to the smoothing time constant N. The second constant N2 is set to a value greater than the first constant N1. When the execution flag Fc is determined to be "1" in this way, that is, when the stop process is being executed, the smoothing time constant N is set to the value of the second constant N2, which is greater than the first constant N1. As a result, even when the torque of the internal combustion engine 10 oscillates at a high frequency, the change in the estimated torque Tee is gradual, and fluctuations are suppressed.

If, in the processing of S100, it is determined that the execution flag Fc is not "1" (S100: YNO), the CPU 72 determines whether the current state is a transient state in which the torque of the internal combustion engine 10 is changing significantly (S110). In the processing of S100, the CPU 72 determines that the current state is a transient state if, for example, any of the following conditions (A) to (C) is met:

Condition (A): The vehicle is accelerating or decelerating.
Condition (B): A predetermined time has elapsed since the fuel cut process was initiated for the internal combustion engine 10. The fuel cut process is a process for stopping fuel injection in all cylinders of the internal combustion engine 10 when a predetermined condition is met.

Condition (C): A predetermined time has passed since the start of the fuel cut recovery process. The fuel cut recovery process is a process that stops the fuel cut process and resumes fuel injection in all cylinders of the internal combustion engine 10 when a predetermined condition is met.

If the processing of S110 determines that the engine is in a transient state (S110: YES), the CPU 72 assigns the first constant N1 to the smoothing time constant N (S130). When it is determined that the engine is in a transient state, the smoothing time constant N is set to the first constant N1, which is smaller than the second constant N2. This improves the responsiveness of the estimated torque Tee when the torque of the internal combustion engine 10 changes significantly.

On the other hand, if it is determined in the process of S110 that the current state is not a transient state (S110: NO), the CPU 72 assigns the second constant N2 to the smoothing time constant N (S140).
Then, when the CPU 72 has completed any one of the processes of S120, S130, and S140, it temporarily ends this process.

<Action and effect>
The operation and effects of this embodiment will be described.
When the above-described stop processing is executed, the smoothing time constant N used to calculate the estimated torque Tee is set to a large value through the processing of S100 and S120 shown in FIG. 4. This reduces fluctuations in the estimated torque Tee during execution of the stop processing, thereby reducing vibrations in the estimated torque Tee. This reduces vibrations in the required second torque base value Tmg2b* calculated in accordance with the estimated torque Tee. This reduces vibrations in the torque of the second motor-generator 54, which is adjusted in accordance with the estimated torque Tee, thereby suppressing vehicle vibrations.

<Example of change>
This embodiment can be modified as follows: This embodiment and the following modifications can be combined and implemented within the scope of technical compatibility.

- In the processing of S120 and S140 shown in FIG. 4, the value assigned to the smoothing time constant N was the same, the second constant N2. Alternatively, the value assigned to the smoothing time constant N in the processing of S120 and S140 may be different. For example, the value assigned to the smoothing time constant N in the processing of S120 may be a value greater than the second constant N2. Also, for example, the value assigned to the smoothing time constant N in the processing of S120 may be a value greater than the first constant N1 and less than the second constant N2.

- In the process of S110 shown in Figure 4, it is determined whether or not the system is in a transient state. In addition, in the process of S110, it may be determined based on other conditions whether to assign a small value or a large value to the smoothing time constant N.

- When calculating the required first torque Tmg1*, the required engine torque Te* is referenced. Alternatively, the estimated torque Tee may be referenced instead of the required engine torque Te*.

- The second superimposed torque ΔTmg2* is variably set based on the engine rotation speed NE, the required engine torque Te*, and the second rotation speed Nmg2. Alternatively, the second superimposed torque ΔTmg2* may be set to a predetermined fixed value.

- The compensation process described above is a process in which the second motor-generator 54 generates a compensation torque to compensate for fluctuations in the rotation of the crankshaft 26 caused by a decrease in the torque of the internal combustion engine 10 due to the cessation of combustion in some cylinders. Alternatively, the compensation torque may be generated by increasing the torque of the cylinders in which combustion occurs even while the stop process is being executed.

The target cylinder for stopping combustion in the stop process may be a cylinder other than cylinder #1.
The number of cylinders for which combustion is to be stopped is not limited to one.
The cylinders in which combustion is stopped may be switched periodically.

- The stop process is not limited to regeneration process. For example, when the oxygen storage amount of the three-way catalyst 32 falls below a specified value, the process may stop combustion in only some cylinders to supply oxygen to the three-way catalyst 32, and control the air-fuel ratio of the mixture in the remaining cylinders to the stoichiometric air-fuel ratio.

The GPF 34 is not limited to being provided downstream of the three-way catalyst 32 in the exhaust passage 30. Furthermore, it is not essential that the aftertreatment device be equipped with a GPF 34. The GPF 34 is not limited to being a filter carrying a three-way catalyst. For example, if a three-way catalyst is provided upstream, it may be a filter alone. Furthermore, for example, it may be a process for stopping combustion in some cylinders in order to adjust the output of the internal combustion engine 10.

- The control device is not limited to one equipped with a CPU 72 and ROM 74 and executing software processing. For example, it may be equipped with a dedicated hardware circuit such as an ASIC that performs hardware processing on at least a portion of what was software processed in the above embodiments. That is, the control device may have any of the following configurations (a) to (c): (a) A processing device that executes all of the above processing in accordance with a program, and a program storage device such as ROM that stores the program. (b) A processing device and program storage device that executes part of the above processing in accordance with a program, and a dedicated hardware circuit that executes the remaining processing. (c) A dedicated hardware circuit that executes all of the above processing. Here, there may be one or any number of software execution devices equipped with a processing device and program storage device, and dedicated hardware circuits.

Instead of directly connecting the ring gear R and the second motor generator 54, a reduction gear may be interposed therebetween.
The hybrid vehicle is not limited to a series-parallel hybrid vehicle. For example, it may be a parallel hybrid vehicle.

10... internal combustion engine 16... port injection valve 20... combustion chamber 22... in-cylinder injection valve 26... crankshaft 32... three-way catalyst 34... GPF
50... Planetary gear mechanism 52... First motor generator 52a... Rotating shaft 54... Second motor generator 54a... Rotating shaft 56... First inverter 58... Second inverter 59... Battery 60... Drive wheels 70... Control device 80... Air flow meter 82... Crank angle sensor 86... Output side rotation angle sensor 88... Current sensor 89... Voltage sensor 90... First rotation angle sensor 92... Second rotation angle sensor 94... Accelerator sensor 100... Transmission

Claims (1)

The present invention is applied to a hybrid vehicle in which a rotating shaft of a rotating electric machine is connected to a crankshaft of an internal combustion engine having a plurality of cylinders,
a stop process for stopping combustion in some cylinders of the internal combustion engine;
a process of calculating an estimated torque base value based on a torque required for the rotary electric machine and an angular acceleration of the rotary electric machine, and performing an smoothing process on the estimated torque base value using an smoothing time constant to calculate an estimated torque that is an estimated value of a torque output from the internal combustion engine;
a process of adjusting a torque output from the rotating electrical machine in accordance with the estimated torque;
and executing a process of setting the smoothing time constant to a larger value while the stop process is being executed than while the stop process is not being executed.