JP7632332B2 - Hybrid vehicle control device - Google Patents

Description

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

For example, the following Patent Document 1 describes an internal combustion engine equipped with a filter in the exhaust passage that captures particulate matter (PM) in the exhaust. A control device that controls this internal combustion engine reduces the opening of the throttle valve if the temperature of the filter becomes high during fuel cut processing. This is intended to reduce the amount of oxygen supplied to the filter and suppress the temperature rise of the filter.

JP 2017-177823 A

However, when fuel cut processing is used to generate vehicle deceleration, the throttle valve opening during fuel cut processing is set to a small value. Therefore, there is a limit to how much the throttle valve opening can be made smaller.

Means for solving the above problems and their effects will be described below.
1. A control device for a hybrid vehicle that is applied to an internal combustion engine and a rotating electric machine, the internal combustion engine having an exhaust passage provided with a filter that collects particulate matter in the exhaust, and configured to execute a first deceleration control process, a second deceleration control process, and a selection process, the first deceleration control process is a process that responds to a deceleration request of the hybrid vehicle by utilizing a fuel cut process, the fuel cut process is a process that stops control of fuel combustion in a cylinder of the internal combustion engine, the second deceleration control process is a process that responds to the deceleration request of the hybrid vehicle without utilizing the fuel cut process, the selection process is a process that selects to execute the second deceleration control process when a PM accumulation amount is equal to or greater than a threshold value, and selects to execute the first deceleration control process when the PM accumulation amount is smaller than the threshold value, and the PM accumulation amount is an amount of particulate matter accumulated in the filter.

When the amount of PM accumulation is large, oxygen flows into the filter, which tends to oxidize a large amount of particulate matter. Therefore, if fuel cut processing is performed when the amount of PM accumulation is large, the filter temperature may become excessively high. Therefore, in the above configuration, when the amount of PM accumulation is equal to or greater than a threshold, a deceleration request is made to the hybrid vehicle without fuel cut processing. This makes it possible to prevent the filter temperature from rising excessively.

2. The control device for a hybrid vehicle described in 1 above, in which the selection process is a process for variably setting the threshold value according to the temperature of the filter, and a process for setting the threshold value when the temperature of the filter is high to be equal to or lower than the threshold value when the temperature of the filter is low.

When the filter temperature is high, the filter temperature is likely to exceed the allowable range when the fuel cut process is performed. Therefore, in the above configuration, by setting a threshold value according to the filter temperature, it is possible to achieve an appropriate compromise between performing the first deceleration control process as much as possible and preventing the filter temperature from becoming excessively high.

3. The hybrid vehicle is a control device for a hybrid vehicle according to 1 or 2, which includes a gear ratio adjustment device and an electric storage device, the crankshaft of the internal combustion engine can be mechanically connected to the drive wheels via the gear ratio adjustment device, the gear ratio adjustment device is a device that adjusts the ratio between the rotation speed of the crankshaft and the rotation speed of the drive wheels, the electric storage device is a device that charges the regenerative power of the rotating electric machine, and the second deceleration control process includes a process of setting the regenerative power and the engine rotation speed according to the charging rate of the electric storage device, and a process of setting the regenerative power when the charging rate of the electric storage device is high to be equal to or lower than the regenerative power when the charging rate is low, and setting the engine rotation speed when the charging rate of the electric storage device is high to be equal to or higher than the engine rotation speed when the charging rate is low.

To maintain the same deceleration force, it is necessary to increase the rotation speed of the internal combustion engine when the regenerative power is small more than when it is large. Therefore, in the above configuration, the engine rotation speed when the regenerative power is small is set to be equal to or higher than the engine rotation speed when the regenerative power is large. This makes it possible to suppress fluctuations in deceleration force due to the magnitude of regenerative power. Furthermore, when the amount of PM accumulation is equal to or greater than a threshold value, by executing the second deceleration control process regardless of the charging rate, it is also possible to suppress fluctuations in deceleration force due to fluctuations in the charging rate.

4. The control device for a hybrid vehicle described in any one of 1 to 3 above is configured to execute a notification process, the notification process being a process of notifying a user that the deceleration will be limited to a smaller value prior to executing the second deceleration control process.

In the above configuration, by executing the notification process, it is possible to make the user aware in advance that the deceleration will be limited to the smaller side.
5. The control device for a hybrid vehicle according to any one of 1 to 4 above, wherein the control device is configured to execute a gradual-change process, the gradual-change process being a process for gradually shifting the deceleration in the first deceleration control process to a deceleration that can be realized by the second deceleration control process prior to switching to the second deceleration control process when the PM accumulation amount becomes equal to or greater than the threshold value during execution of the first deceleration control process.

In the above configuration, the deceleration is gradually changed when switching from the first deceleration control process to the second deceleration control process. This makes it possible to prevent the user from feeling uncomfortable about the behavior of the hybrid vehicle.

6. A control device for a hybrid vehicle as described in any one of 1 to 5 above, configured to execute the second deceleration control process in response to a deceleration request of the hybrid vehicle even if the PM accumulation amount becomes smaller than the threshold value if there is a history of execution of the second deceleration control process within one trip.

In the above configuration, once the second deceleration control process is executed, the second deceleration control process is adopted for that trip even if the amount of PM accumulation falls below the threshold value. This makes it possible to prevent the deceleration of the hybrid vehicle from switching frequently.

FIG. 1 is a diagram showing a configuration of a vehicle according to an embodiment. 4 is a flowchart showing a procedure of a process executed by a control device according to the embodiment. FIG. 4 is a diagram showing a trend of map data according to the embodiment. 4 is a flowchart showing a procedure of a process executed by a control device according to the embodiment. 4 is a flowchart showing a procedure of a process executed by a control device according to the embodiment. 10 is a flowchart showing a procedure of a process executed by a control device according to a second embodiment. 4 is a time chart showing the operation according to the embodiment.

Hereinafter, an embodiment will be described with reference to the drawings.
"Prerequisite configuration"
As shown in Fig. 1, an internal combustion engine 10 has four cylinders #1 to #4. A throttle valve 14 is provided in an intake passage 12 of the internal combustion engine 10. A port injection valve 16 that injects fuel into an intake port 12a, which is a downstream portion of the intake passage 12, is provided. Air taken into the intake passage 12 and fuel injected from the port injection valve 16 flow into a combustion chamber 20 when an intake valve 18 opens. Fuel is injected into the combustion chamber 20 from an in-cylinder injection valve 22. The mixture of air and fuel in the combustion chamber 20 is combusted in response to spark discharge from an ignition device 24. The combustion energy generated at this time is converted into the rotational energy of a crankshaft 26.

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

The crankshaft 26 is mechanically connected to the carrier C of the planetary gear mechanism 50 that constitutes the power split device. The rotating shaft 52a of the first motor generator 52 is mechanically connected to the sun gear S of the planetary gear mechanism 50. The rotating shaft 54a of the second motor generator 54 and the drive wheels 60 are mechanically connected to the ring gear R of the planetary gear mechanism 50. An AC voltage is applied to the terminals of the first motor generator 52 by the first inverter 56. An AC voltage is applied to the terminals of the second motor generator 54 by the second inverter 58. Both the first inverter 56 and the second inverter 58 are power conversion circuits that convert the terminal voltage of the battery 59, which serves as a DC voltage source, into an AC voltage and output it.

The control device 70 controls the internal combustion engine 10. The control device 70 operates the operation parts of the internal combustion engine 10, such as the throttle valve 14, the port injection valve 16, the in-cylinder injection valve 22, and the ignition device 24, in order to control the torque and exhaust component ratio, which are the controlled variables of the controlled variables. The control device 70 also operates the first inverter 56 in order to control the torque, which is the controlled variable of the first motor generator 52 as the controlled variable. The control device 70 also operates the second inverter 58 in order to control the torque, which is the controlled variable of the second motor generator 54 as the controlled variable. FIG. 1 shows the operation signals MS1 to MS6 of the throttle valve 14, the port injection valve 16, the in-cylinder injection valve 22, the ignition device 24, the first inverter 56, and the second inverter 58. The control device 70 refers to the intake air amount Ga detected by the air flow meter 80 and the output signal Scr of the crank angle sensor 82 in order to control the controlled variables of the internal combustion engine 10. The control device 70 also refers to a water temperature THW detected by a water temperature sensor 84 and an output signal Sp of an output side rotation angle sensor 86 that detects the rotation angle of the ring gear R. The control device 70 also refers to a charge/discharge current I of the battery 59 detected by a current sensor 88. The control device 70 also refers to a temperature Tb of the battery 59 detected by a temperature sensor 89. The control device 70 also refers to an output signal Sm1 of a first rotation angle sensor 90 that detects the rotation angle of the first motor generator 52 in order to control the control amount of the first motor generator 52. The control device 70 also refers to an output signal Sm2 of a second rotation angle sensor 92 that detects the rotation angle of the second motor generator 54 in order to control the control amount of the second motor generator 54. The control device 70 also refers to an accelerator operation amount ACCP, which is the amount of depression of the accelerator pedal detected by an accelerator sensor 94, and a shift variable Vsft detected by a shift position sensor 96. The shift variable Vsft is a variable that indicates the shift position, such as D range, B range, P range, or N range.

The control device 70 includes a CPU 72, a ROM 74, and a peripheral circuit 76, which are capable of communicating with each other via a communication line 78. Here, the peripheral circuit 76 includes a circuit that generates a clock signal that regulates the internal operation, a power supply circuit, a reset circuit, and the like. The control device 70 controls the control amount by the CPU 72 executing a program stored in the ROM 74.

"Processing for the protection of GPF34"
Fig. 2 shows the procedure of the process related to protection of the GPF 34. 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, 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, the charging efficiency η, and the 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 intake air amount Ga and the engine speed NE. Next, the CPU 72 calculates the temperature Tgpf of the GPF 34 and the update amount ΔDPM of the PM accumulation amount DPM based on the engine speed NE, the charging efficiency η, and the water temperature THW (S12). Here, the PM accumulation amount DPM is the amount of PM trapped in the GPF 34. In detail, the CPU 72 calculates the amount of PM in the exhaust discharged to the exhaust passage 30 based on the engine speed NE, the charging efficiency η, and the water temperature THW. The CPU 72 also calculates the temperature Tgpf of the GPF 34 based on the engine speed NE and the 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 Tgpf of the GPF 34. Next, the CPU 72 adds the update amount ΔDPM to the PM accumulation amount DPM and assigns the result to the PM accumulation amount DPM (S14).

Next, the CPU 72 inputs the PM accumulation amount DPM and the temperature Tgpf to calculate the FC possible time Tfc, which is the time during which the fuel cut process can be continued (S16). The FC possible time Tfc is the upper limit time during which the temperature Tgpf of the GPF 34 does not become excessively high. This process is realized by the CPU 72 performing map calculations to determine the FC possible time Tfc, with map data stored in advance in the ROM 74, in which the PM accumulation amount DPM and the temperature Tgpf are input variables and the FC possible time Tfc is an output variable.

FIG. 3 shows an example of the map data.
As shown in Fig. 3, the FC possible time Tfc when the PM accumulation amount DPM is large is set to be equal to or shorter than the FC possible time Tfc when the PM accumulation amount DPM is small. This is because the larger the PM accumulation amount DPM is, the greater the amount of PM oxidized per unit time when oxygen flows into the GPF 34. In addition, the FC possible time Tfc when the temperature Tgpf is high is set to be equal to or shorter than the FC possible time Tfc when the temperature Tgpf is low. This is because the higher the temperature Tgpf is, the shorter the time it takes for the temperature Tgpf to reach the upper limit value becomes.

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. The map calculation may be a process in which, when the value of an input variable matches any of the values of the input variables in the map data, the value of the corresponding output variable in the map data is used as the calculation result. The map calculation may be a process in which, when the value of an input variable does not match any of the values of the input variables in the map data, the value obtained by interpolating the values of multiple output variables included in the map data is used as the calculation result. The map calculation may be a process in which, when the value of an input variable does not match any of the values of the input variables in the map data, the value of the output variable in the map data that corresponds to the closest value among the values of multiple output variables included in the map data is used as the calculation result.

Returning to FIG. 2, the CPU 72 determines whether the protection flag F1 is "1" (S18). The protection flag F1 is set to "1" when processing is executed to protect the GPF 34 against overheating. The protection flag F1 is set to "0" when processing is not executed to protect the GPF 34 against overheating.

When the CPU 72 determines that the protection flag F1 is "0" (S18: NO), it determines whether the FC possible time Tfc is equal to or less than the threshold value Tth (S20). This process is for determining whether or not to change the magnitude of the required drive torque Tp* when the accelerator operation amount ACCP is equal to or less than a predetermined value. The threshold value Tth is set according to the average duration during which the required drive torque Tp* is negative. The threshold value Tth may be set to, for example, "5 seconds" or less.

The process of S20 is equivalent to the process of determining whether the PM deposition amount DPM is equal to or greater than a threshold value. However, the threshold value is set according to the temperature Tgpf. That is, FIG. 3 shows the threshold values Dα and Dβ of the PM deposition amount DPM when the temperature Tgpf is temperature Tα and temperature Tβ, respectively. As shown in FIG. 3, the threshold value Dα when the temperature Tgpf is temperature Tα is smaller than the threshold value Dβ when the temperature Tgpf is temperature Tβ, which is lower than temperature Tα.

Returning to FIG. 2, if the CPU 72 determines that the deceleration is equal to or less than the threshold value Tth (S20: YES), the CPU 72 notifies the user that the deceleration will be changed by operating the human interface 98 shown in FIG. 1 (S22). For example, if the human interface 98 is a warning light, this process may be a process of turning the light on. However, the manual for the vehicle VC should state what meaning the light has. However, the human interface 98 is not limited to a device that outputs visual information. For example, it may be a speaker. In that case, audio information such as "Switching to a mode that prioritizes protection of the GPF 34" may be output.

Then, the CPU 72 waits until a predetermined time T1, which has a predetermined length, has elapsed since the execution of the process of S22 (S24: NO). If the CPU 72 determines that the predetermined time T1 has elapsed (S24: YES), it assigns "1" to the protection flag F1 (S26).

On the other hand, when the CPU 72 determines that the protection flag F1 is "1" (S18: YES), it determines whether the trip has ended (S28). Here, a trip refers to a period during which the vehicle's travel permission switch is in the ON state. The travel permission switch may be, for example, a switch that closes a switch that opens and closes the electrical path between the battery 59 and the first inverter 56 and the second inverter 58.

When determining that the trip has ended (S28: YES), the CPU 72 sets the protection flag F1 to "0" (S29).
When the CPU 72 completes the processes of S26 and S29, or when a negative determination is made in the processes of S20 and S28, the CPU 72 temporarily ends the series of processes shown in FIG.

"Processing related to motor generator control"
4 shows a procedure for processing related to control of the outputs of the first motor generator 52 and the second motor generator 54. The processing shown in FIG. 4 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. 4, the CPU 72 acquires the accelerator operation amount ACCP, the output side rotation speed Np, and the shift variable Vsft (S30). Here, the output side rotation speed Np is the rotation speed of the ring gear R of the planetary gear mechanism 50. The output side rotation speed Np is a variable that indicates the rotation speed of the drive wheels 60. 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.

Next, the CPU 72 determines whether the protection flag F1 is "0" (S32). When the CPU 72 determines that the protection flag F1 is "0" (S32: YES), it uses the normal map to calculate the required drive torque Tp*, which is the torque required for the drive wheels 60 (S36). The map data of the normal map is data in which the required drive torque Tp* when the accelerator operation amount ACCP is equal to or less than a predetermined value is set to a value that can be realized when the fuel cut process is executed. Here, the value that can be realized when the fuel cut process is executed means a value that can be realized when the fuel cut process is executed regardless of the charging rate SOC. In other words, it means a value that can be realized without regenerative control of the second motor generator 54. Incidentally, the minimum value of the required drive torque Tp* in the B range may be set according to the output of the internal combustion engine 10 that can be realized when the engine rotation speed NE is set to the maximum rotation speed while executing the fuel cut process.

On the other hand, when the CPU 72 determines that the protection flag F1 is "1" (S32: NO), it uses the protection map to calculate the required drive torque Tp*, which is the torque required for the drive wheels 60 (S34). The protection map data is data in which the required drive torque Tp* when the accelerator operation amount ACCP is equal to or less than a predetermined value is set to a value that can be realized by the load torque of the internal combustion engine 10 without performing a fuel cut process. Here, the value that can be realized by the load torque of the internal combustion engine 10 without performing a fuel cut process means a value that can be realized regardless of the charging rate SOC. In this case, the required drive torque Tp* is set to a value that can be realized by the minimum charging efficiency η that can stabilize the combustion of the internal combustion engine 10 while keeping the engine rotation speed NE as high as possible. Specifically, in the case of the D range, the required drive torque Tp* is set to a value that can be realized by the minimum charging efficiency η that can stabilize the combustion of the internal combustion engine 10 while keeping the engine rotation speed NE at a value that is a certain amount smaller than the maximum value. On the other hand, in the case of the B range, the required drive torque Tp* is set to a value that can be realized by the minimum charging efficiency η that can stabilize the combustion of the internal combustion engine 10 while maximizing the engine speed NE. Incidentally, it is preferable that the CPU 72 controls the air-fuel ratio of the mixture in the combustion chamber 20 to the theoretical air-fuel ratio. This makes it possible to reduce the amount of oxygen flowing into the GPF 34 to almost zero.

When the CPU 72 completes the processing of S34 and S36, it assigns the product of the required drive torque Tp* and the output side rotation speed Np to the traveling power Pp* (S38). 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 and the temperature Tb of the battery 59 (S40). The required charge/discharge power Pbatt* is positive when discharging. In more detail, when the charging rate SOC is equal to or lower than a predetermined value, the CPU 72 sets the required charge/discharge power Pbatt* to negative in order to charge the battery 59. The charging rate SOC is calculated by the CPU 72 based on the charging/discharging current I.

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 system output Ps* (S42).
Next, the CPU 72 calculates a target engine speed NE* and a target first rotation speed Nmg1* (S44). Here, the target engine speed NE* is a target value of the engine speed NE. The target first rotation speed Nmg1* is a target value of the first rotation speed Nmg1, which is the rotation speed of the rotary shaft 52a of the first motor generator 52. More specifically, the process of S44 is as follows.

First, the CPU 72 sets the required engine power Pe* according to the system power Ps*. Here, the CPU 72 may substitute the system power Ps* for the required engine power Pe*. However, instead of this, the CPU 72 may substitute a value obtained by adding an operation amount for controlling the charge/discharge power Pbatt to the required charge/discharge power Pbatt* to the system power Ps* for the required engine power Pe*. Then, the CPU 72 calculates the target engine speed NE* based on the required engine power Pe*. This can be realized by the CPU 72 performing map calculations on the target engine speed NE* in a state where map data is stored in advance 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.

Next, the CPU 72 calculates the target first rotation speed Nmg1* based on the following formula.
NE*={ρ/(1+ρ)}・Nmg1*+{1/(1+ρ)}・Np
Here, the planetary gear ratio ρ in the above formula is the number of teeth of the sun gear S divided by the number of teeth of the ring gear R.

Next, the CPU 72 assigns the value obtained by subtracting the first rotation speed Nmg1 from the target first rotation speed Nmg1* to the error err1 (S46). Note that the first rotation speed Nmg1 is calculated by the CPU 72 based on the output signal Sm1.

Next, the CPU 72 assigns a value obtained by dividing the required engine output Pe* by the target engine rotation speed NE* to an engine torque base value Teb (S48).
Next, the CPU 72 calculates the required first torque Tmg1* (S50). The required first torque Tmg1* is the torque required for the first motor generator 52. The CPU 72 sets the required first torque Tmg1* as the sum of an open loop term and a feedback term. Here, the open loop term is "{-ρ/(1+ρ)}·Teb". Here, "-ρ/(1+ρ)" is a coefficient for converting the torque of the carrier C into the torque of the sun gear S. On the other hand, the feedback term is a manipulated variable for feedback control of the first rotation 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 a value obtained by multiplying the error err1 by the proportional gain Kp. The output value of the integral element is an integrated value obtained by multiplying the error err1 by the integral gain Ki.

Next, the CPU 72 multiplies "(-1)/ρ" by the required first torque Tmg1* and assigns the result to the direct torque Ted (S52). Here, "(-1)/ρ" is a coefficient that converts the torque of the sun gear S into the torque of the ring gear R. The direct torque Ted is a calculated torque that is assumed to be applied to the ring gear R.

Next, the CPU 72 calculates the required second torque Tmg2* by subtracting the direct torque Ted from the required drive torque Tp* (S54). Here, the value obtained by subtracting the direct torque Ted from the required drive torque Tp* is the shortage of the output of the ring gear R when making the torque of the drive wheels 60 the required drive torque Tp*.

Next, the CPU 72 outputs an operation signal MS5 to the first inverter 56 and outputs an operation signal MS6 to the second inverter 58 (S56). That is, the CPU 72 operates the first inverter 56 to control the torque of the first motor generator 52 to the required first torque Tmg1*. The CPU 72 also operates the second inverter 58 to control the torque of the second motor generator 54 to the required second torque Tmg2*.

When the process of S56 is completed, the CPU 72 temporarily ends the series of processes shown in FIG.
"Operation process of throttle valve 14"
Fig. 5 shows a procedure of a process related to the operation of the throttle valve 14. The process shown in Fig. 5 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. 5, the CPU 72 first acquires the required engine power Pe* and the target engine speed NE* (S60). Then, the CPU 72 assigns the value obtained by dividing the required engine power Pe* by the target engine speed NE* to the required engine torque Te* (S62). Next, the CPU 72 calculates the throttle opening command value TA*, which is a command value for the opening degree of the throttle valve 14, based on the required engine torque Te* (S64). The throttle opening command value TA* calculated here is a value for making the torque of the internal combustion engine 10 the required engine torque Te*. Then, the CPU 72 outputs an operation signal MS1 to the throttle valve 14 to control the opening degree of the throttle valve 14 to the throttle opening command value TA* (S66).

When completing the process of S66, the CPU 72 temporarily ends the series of processes shown in FIG.
"Actions and Effects of the Present Embodiment"
The CPU 72 calculates the required drive torque Tp* based on the accelerator operation amount ACCP and the output side rotation speed Np, and operates various operating parts of the internal combustion engine 10, the first inverter 56, and the second inverter 58 based on this. When the accelerator operation amount ACCP is equal to or less than a predetermined amount, the CPU 72 sets the required drive torque Tp* to a negative value. Here, the CPU 72 normally sets the required drive torque Tp* to a value that can be realized by the internal combustion engine 10 executing a fuel cut process.

The CPU 72 also calculates the PM accumulation amount DPM, which is the amount of particulate matter accumulated in the GPF 34, and the temperature Tgpf of the GPF 34. Based on these, the CPU 72 calculates the upper limit time during which the temperature of the GPF 34 does not exceed the allowable range, assuming that the fuel cut process is continued, as the FC possible time Tfc. When the FC possible time Tfc is equal to or less than the threshold value Tth, the CPU 72 changes the map data for calculating the required drive torque Tp* to map data for protecting the GPF 34. The protection map data is set to a value that can be realized based on the load torque of the internal combustion engine 10 when the fuel cut process is not performed. Therefore, even if the required drive torque Tp* cannot be realized by the power generation of the second motor generator 54, the CPU 72 can realize the required drive torque Tp* by the load torque of the internal combustion engine 10 without performing the fuel cut process. That is, the CPU 72 can generate a negative driving force by lowering the charging efficiency η of the internal combustion engine 10 according to the accelerator operation amount ACCP and controlling the engine rotation speed NE by operating the first inverter 56. This can reduce the oxygen concentration in the fluid flowing into the GPF 34, and thus can prevent the temperature of the GPF 34 from rising excessively due to the oxidation of PM in the GPF 34.

According to the present embodiment described above, the following actions and effects can be obtained.
(1) Prior to selecting the protection map data, the CPU 72 notifies the driver of the selection. This makes it possible to prevent the driver from getting the impression that the deceleration in response to the accelerator operation has suddenly changed. This makes it possible to prevent the driver from feeling uncomfortable.

(2) The CPU 72 switches to protective map data when the FC possible time Tfc is equal to or less than the threshold value Tth, regardless of the current charging rate SOC. This makes it possible to maintain a constant deceleration rate in response to accelerator operation, regardless of the charging rate SOC.

(3) When the CPU 72 decelerates the vehicle VC using the protection map, the engine speed NE is set according to the charging rate SOC of the battery 59. That is, according to the processing of S42, the system output Ps* is determined according to the charging rate SOC. That is, the required engine output Pe* is determined according to the charging rate SOC. Then, in the processing of S44, the CPU 72 determines the target engine speed NE* according to the required engine output Pe*. Therefore, when the system output Ps* is a value that decelerates the vehicle VC, the target engine speed NE* when the charging rate SOC is high is equal to or higher than the target engine speed NE* when the charging rate SOC is low. This allows the engine speed NE to be increased when the regenerative power of the second motor generator 54 is low, more than when it is high. This makes it possible to suppress fluctuations in deceleration force depending on the magnitude of the regenerative power.

(4) Regardless of whether fuel cut processing is currently being performed, when the FC possible time Tfc becomes equal to or less than the threshold value Tth, the CPU 72 switches to the protective map data and notifies the driver accordingly. This allows the driver to be reliably notified in advance that the deceleration rate in response to accelerator operation will be changed.

(5) Even in the protective map data, the deceleration in B range is made greater than the deceleration in D range. This allows the driver to feel the difference in deceleration depending on the shift position even after switching to the protective map data.

Second Embodiment
The second embodiment will be described below with reference to the drawings, focusing on the differences from the first embodiment.

In this embodiment, when the protection flag F1 switches from "0" to "1" during deceleration, a process for gradually increasing the driving force is executed.
The procedure for the above process is shown in Fig. 6. The process shown in Fig. 6 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. 6, the CPU 72 determines whether the gradual change flag F2 is "1" (S70). When the gradual change flag F2 is "1", it indicates that the process of gradually increasing the driving force to a value that can be achieved by the protection map is being executed. When the gradual change flag F2 is "0", it indicates that the gradual increase process is not being executed.

When the CPU 72 determines that the gradual change flag F2 is "0" (S70: NO), it determines whether the protection flag F1 has switched from "0" to "1" (S72). When the PU 72 determines that the protection flag F1 has switched (S72: YES), it determines whether the vehicle VC is decelerating (S74). When the CPU 72 determines that the vehicle VC is decelerating (S74: YES), it assigns "1" to the gradual change flag F2 (S76).

When the CPU 72 determines that the gradual change flag F2 is "1" (S70: YES) and when the processing of S76 is completed, the CPU 72 gradually increases the required drive torque Tp* (S78). The CPU 72 then determines whether the gradual increase processing is completed (S80). The CPU 72 determines that the gradual increase processing is completed when the required drive torque Tp* becomes a value that can be achieved using the protection map.

When determining that the gradual increase process is completed (S80: YES), the CPU 72 sets the gradual change flag F2 to "0" (S84).
When the CPU 72 completes the process of S84 or makes a negative determination in the processes of S72, S74, or S80, the CPU 72 temporarily ends the series of processes shown in FIG.

"Actions and Effects of the Second Embodiment"
7 illustrates an example of processing when the protection flag F1 is switched from "0" to "1" during deceleration. In FIG. 7, the threshold value of the PM accumulation amount DPM, which is the PM accumulation amount DPM at which the FC possible time Tfc becomes equal to or less than the threshold value Tth, is indicated by a dashed dotted line.

As shown in FIG. 7, when the FC possible time Tfc becomes equal to or less than the threshold value Tth at time t1, the CPU 72 switches the protection flag F1 from "0" to "1" at time t2, a predetermined time T1 after that. The CPU 72 then gradually increases the required drive torque Tp*, as shown by the solid line in FIG. 7. Then, at time t3, when the required drive torque Tp* becomes a value that can be achieved by the protection map, the CPU 72 switches the map used to calculate the required drive torque Tp* from the normal map to the protection map.

<Correspondence>
In the following, the correspondence is shown for each of the numbers of the means for solving the problem listed in the "Means for solving the problem" column. [1] The rotating electric machine corresponds to the second motor generator 54. The filter corresponds to the GPF 34. The first deceleration control process corresponds to the processes of S36, S38 to S56, and S60 to S66 when the required drive torque Tp* is negative. The second deceleration control process corresponds to the processes of S34, S38 to S56, and S60 to S66 when the required drive torque Tp* is negative. The fuel cut process corresponds to the process enabled by the process of S36. The selection process corresponds to the process shown in FIG. 2. The threshold corresponds to the thresholds Dα and Dβ. [2] It corresponds to the threshold Dα being smaller than the threshold Dβ. [3] The gear ratio adjusting device corresponds to the planetary gear mechanism 50 and the first motor generator 52. The power storage device corresponds to the battery 59. [4] The notification process corresponds to the process of S22. [5] The gradual change process corresponds to the process of S78. [6] In Fig. 2, when the process of S26 is executed, this corresponds to the process of S29 not being executed unless the trip ends.

<Other embodiments>
This embodiment can be modified as follows: This embodiment and the following modifications can be combined with each other to the extent that no technical contradiction occurs.

"First Deceleration Control Process"
The first deceleration control process is not limited to the process of executing the processes of S36, S38 to S56, and S60 to S66. For example, it may be a process of generating a braking force only by a fuel cut process. In other words, it may be a process of responding to a deceleration request only by the load torque of the internal combustion engine 10, without responding to the deceleration request by cooperation between the regenerative control of the rotating electric machine and the load torque by the fuel cut process.

"Second Deceleration Control Process"
The second deceleration control process is not limited to a process that responds to a deceleration request by utilizing rotational speed control of the first motor generator 52. For example, as described in the section "Gear Ratio Adjustment Device" below, if the vehicle is equipped with a stepped transmission, the deceleration request may be responded to by adjusting the gear ratio of the stepped transmission. In this case, when the regenerative power by the second motor generator 54 is small, the gear ratio is manipulated so as to increase the engine rotational speed NE.

The second deceleration control process is not limited to a process that generates a desired braking force in cooperation with the regenerative power of the rotating electric machine. For example, it may be a process that generates a desired braking force using only the power of the internal combustion engine 10. In other words, it may be a process that responds to a deceleration request using only the load torque of the internal combustion engine 10, without responding to the deceleration request through cooperation between the regenerative control of the rotating electric machine and the load torque of the internal combustion engine 10.

It is not essential that the required drive torque Tp* be different between the B range and the D range.
"About selection processing"
The process is not limited to the process of selecting which of the first deceleration control process and the second deceleration control process to adopt depending on whether the FC possible time Tfc is equal to or less than the threshold value Tth. For example, the process may be a process in which the CPU 72 determines whether the PM accumulation amount DPM is equal to or more than a threshold value. Here, the CPU 72 may variably set the threshold value depending on the temperature Tgpf. However, it is not essential to variably set the threshold value.

"Execution Period of First Deceleration Control Process and Second Deceleration Control Process"
In the above embodiment, when the protection flag F1 is set to "1", the protection flag F1 is not set to "0" during the trip, but this is not limited to the above. In other words, when the second deceleration control process is once selected, the first deceleration control process is not selected during the trip, but this is not limited to the above. For example, when the duration of the state in which the FC possible time Tfc is greater than the threshold value Tth is equal to or longer than a specified time, the protection flag F1 may be set to "0".

- In the above embodiment, the protection flag F1 is switched from "0" to "1" during the trip, but this is not limited to the above. For example, the process in FIG. 2 may be executed only at the start and end of the trip. In other words, the process for selecting whether to use the first deceleration control process or the second deceleration control process may be executed only at the start of the trip.

"About the gear ratio adjustment device"
The gear ratio adjustment device is not limited to the device including the planetary gear mechanism 50 and the first motor generator 52. For example, the gear ratio adjustment device may be a gear shift device such as a stepped gear shift device that changes the gear ratio by changing the engagement state of a plurality of gears.

"About Hybrid Vehicles"
The hybrid vehicle is not limited to a series-parallel hybrid vehicle. For example, it may be a parallel hybrid vehicle.

<Additional Notes>
The present invention is applied to a vehicle equipped with an internal combustion engine and a gear ratio adjustment device, the internal combustion engine having an exhaust passage provided with a filter for collecting particulate matter in the exhaust, a crankshaft of the internal combustion engine being mechanically connectable to drive wheels via the gear ratio adjustment device, the gear ratio adjustment device being a device for adjusting the ratio between the rotation speed of the crankshaft and the rotation speed of the drive wheels, and executing a deceleration control process, a prediction process, and a limiting process, the deceleration control process being a process for controlling the deceleration of the vehicle by operating the gear ratio adjustment device when a deceleration request for the vehicle occurs, and at least the limiting process being executed. The deceleration control device for a vehicle in which the deceleration control processing when there is no particulate matter includes a fuel cut processing, which is a processing for stopping the supply of fuel to cylinders of the internal combustion engine, the prediction processing is a processing for predicting whether or not the temperature of the filter will rise beyond an acceptable range when the fuel cut processing is executed in response to the deceleration request based on the amount of particulate matter captured in the filter, and the limitation processing is a processing for limiting the deceleration of the vehicle to a smaller side when a deceleration request for the vehicle is made if the prediction processing predicts that the temperature of the filter will rise beyond an acceptable range.

When fuel cut processing is being performed, the deceleration can be increased as the rotation speed of the crankshaft of the internal combustion engine is increased relative to the rotation speed of the drive wheels. However, fuel cut processing causes a large amount of oxygen to flow into the filter, which can easily lead to an increase in the filter temperature. In particular, when the rotation speed during filter processing is high, the amount of oxygen flowing into the filter per unit time is greater than when the rotation speed is low. Therefore, the filter temperature is likely to become excessively high due to the oxidation heat of the particulate matter captured by the filter. Therefore, in the above configuration, when it is predicted that the filter temperature will rise beyond the allowable range, the deceleration is limited to a small value. This makes it possible to reduce the amount of oxygen flowing into the filter, thereby preventing the filter temperature from rising excessively.

Regarding the deceleration control process in the above supplementary note: It is not essential to use different maps depending on the shift position. For example, a common map may be used for the D range and the B range. In that case, the minimum drive torque obtained while executing the combustion control of the internal combustion engine 10 may be set as the minimum value of the drive torque.

The deceleration control process is not limited to limiting the minimum value of the drive torque in each range to a larger value. In other words, it is not limited to limiting the maximum value of the deceleration torque in each range to a smaller value. For example, it may be a process that prohibits a range where the drive torque is particularly small, such as B range.

The deceleration control process is not limited to a process that applies a negative drive torque to the drive wheels 60 while executing combustion control of the internal combustion engine 10. For example, it may be a process that limits the engine rotation speed NE to a smaller value. This also reduces the amount of oxygen flowing into the GPF 34 per unit time.

Regarding the prediction process in the above appendix: The prediction process is not limited to a process that predicts based on the temperature Tgpf and the PM accumulation amount DPM at each time. For example, as described in the "Notification process" section, if the notification process is executed before the start of the vehicle VC, a process may be performed to determine whether the FC possible time Tfc is equal to or less than the threshold value Tth before the start. In this case, the FC possible time Tfc may be calculated, for example, using only the PM accumulation amount DPM as an input. Alternatively, the PM accumulation amount DPM and the temperature at the start of the internal combustion engine 10 may be calculated as inputs. Furthermore, for example, when the destination of the vehicle VC is set, a variable indicating the route to the destination may be included in the input. In that case, when the route to the destination is entirely in an urban area, it may be determined that the FC possible time Tfc is equal to or less than the threshold value Tth when the PM accumulation amount DPM is larger than when the route includes many downhill sections.

Regarding the notification process in the above appendix: Fig. 3 illustrates an example in which the notification is given to limit the deceleration while the vehicle VC is traveling, but this is not limiting. For example, the notification process may be executed only before the vehicle VC starts moving. Specifically, the notification process may be executed when the system main relay connecting the first inverter 56 and the second inverter 58 to the battery 59 is switched to a closed state.

10: internal combustion engine 26: crankshaft 30: exhaust passage 32: three-way catalyst 34: GPF
50: Planetary gear mechanism 52: First motor generator 54: Second motor generator 56: First inverter 58: Second inverter 59: Battery 60: Drive wheels 70: Control device

Claims (5)

The present invention is applied to a hybrid vehicle equipped with an internal combustion engine and a rotating electric machine,
the internal combustion engine is provided with a filter in an exhaust passage for collecting particulate matter in the exhaust gas;
configured to execute a first deceleration control process, a second deceleration control process, and a selection process;
the first deceleration control process is a process for responding to a deceleration request of the hybrid vehicle by utilizing a fuel cut process,
the fuel cut process is a process for stopping fuel combustion control in a cylinder of the internal combustion engine,
the second deceleration control process is a process for responding to a deceleration request of the hybrid vehicle without using the fuel cut process,
the selection process is a process of selecting to execute the second deceleration control process when the PM accumulation amount is equal to or greater than a threshold, and selecting to execute the first deceleration control process when the PM accumulation amount is smaller than the threshold,
The PM accumulation amount is an amount of particulate matter accumulated in the filter,
configured to perform a gradual change process;
A control device for a hybrid vehicle, wherein the gradual change processing is a processing for gradually transitioning in the first deceleration control processing to a deceleration that can be achieved by the second deceleration control processing prior to switching to the second deceleration control processing when the PM accumulation amount becomes equal to or greater than the threshold value while the first deceleration control processing is being executed . The present invention is applied to a hybrid vehicle equipped with an internal combustion engine and a rotating electric machine,
the internal combustion engine is provided with a filter in an exhaust passage for collecting particulate matter in the exhaust gas;
configured to execute a first deceleration control process, a second deceleration control process, and a selection process;
the first deceleration control process is a process for responding to a deceleration request of the hybrid vehicle by utilizing a fuel cut process,
the fuel cut process is a process for stopping fuel combustion control in a cylinder of the internal combustion engine,
the second deceleration control process is a process for responding to a deceleration request of the hybrid vehicle without using the fuel cut process,
the selection process is a process of selecting to execute the second deceleration control process when the PM accumulation amount is equal to or greater than a threshold, and selecting to execute the first deceleration control process when the PM accumulation amount is smaller than the threshold,
The PM accumulation amount is an amount of particulate matter accumulated in the filter,
A control device for a hybrid vehicle that is configured to execute the second deceleration control process in response to a deceleration request of the hybrid vehicle even if the PM accumulation amount becomes smaller than the threshold value if there is a history of executing the second deceleration control process within a trip . 3. The control device for a hybrid vehicle according to claim 1, wherein the selection process is a process for variably setting the threshold value according to the temperature of the filter, and a process for setting the threshold value when the temperature of the filter is high to be equal to or lower than the threshold value when the temperature of the filter is low. The hybrid vehicle includes a gear ratio adjusting device and a power storage device,
a crankshaft of the internal combustion engine is mechanically connectable to a drive wheel via the speed change ratio adjusting device;
the speed change ratio adjustment device is a device for adjusting a ratio between a rotation speed of the crankshaft and a rotation speed of the drive wheels,
the power storage device is a device that stores regenerative power from the rotating electric machine,
4. The control device for a hybrid vehicle according to claim 1, wherein the second deceleration control process includes a process for setting the regenerative power and the engine rotation speed according to the charging rate of the power storage device, and a process for setting the regenerative power when the charging rate of the power storage device is high to be equal to or lower than the regenerative power when the charging rate is low, and for setting the engine rotation speed when the charging rate of the power storage device is high to be equal to or higher than the engine rotation speed when the charging rate is low. configured to execute a notification process;
5. The control device for a hybrid vehicle according to claim 1 , wherein the notification process notifies a user that the deceleration will be limited to a smaller value prior to execution of the second deceleration control process.

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