JP7222307B2 - vehicle controller - Google Patents

Description

The present invention relates to a vehicle control device that controls a hybrid vehicle.

2. Description of the Related Art Conventionally, as seen in Patent Document 1, a hybrid vehicle is known in which an engine, two generator-motors, a first generator-motor and a second generator-motor, and a wheel shaft are connected via a planetary gear mechanism. In such a hybrid vehicle, one of the three rotating elements of the planetary gear mechanism is the engine, one of the remaining two rotating elements is the first generator-motor, and the last one is the second generator-motor. are connected to the wheel axles.

In such a hybrid vehicle, a driving mode can be selected from a plurality of driving modes including an engine driving mode in which the engine is running and an EV driving mode in which the engine is stopped and powered by the second generator motor. Select and run. Then, during the selection of the engine driving mode, the target engine speed, which is the target value of the engine speed, is set according to the driving conditions and the state of charge of the battery, and the engine speed is maintained at the target engine speed. The torque generated by the first generator motor is feedback-controlled.

Japanese Patent Application Laid-Open No. 2010-110632

In the hybrid vehicle as described above, even when the engine cannot generate sufficient torque, it is possible to continue running in the engine running mode by maintaining the engine speed with the torque of the first generator motor. It is possible. However, in such a state, electric power is consumed to maintain the engine speed, so the distance that the vehicle can continue running is shortened accordingly.

A vehicle control device for solving the above problems includes an engine, two generator motors of a first generator motor and a second generator motor, a planetary gear mechanism having three rotating elements of a sun gear, a ring gear, and a planetary carrier, a battery that stores electric power generated by the first generator-motor and the second generator-motor and supplies the stored electric power to the first generator-motor and the second generator-motor; and one of the three rotating elements. The engine is connected to the first, the first generator-motor is connected to one of the remaining two, and the second generator-motor and the wheel shaft are connected to the last one, respectively. The vehicle control device selects one of a plurality of driving modes including an engine driving mode in which the vehicle is driven with the engine running and an EV driving mode in which the vehicle is driven by the power of the second generator motor with the engine stopped. Driving control of the hybrid vehicle is performed by selecting one of the driving modes. Further, the vehicle control device determines whether or not the engine is in a state in which it cannot generate sufficient torque, and if it determines that it is in a state in which it cannot generate sufficient torque, it prohibits selection of the engine driving mode. It has a travel prohibition control unit.

If the engine cannot generate sufficient torque due to poor combustion or the like while the engine driving mode is selected, the engine speed is maintained by the power of the first generator-motor, and the power of the second generator-motor is used for driving. Driving force must be secured. At this time, if the vehicle is switched to the EV driving mode, the power consumption is reduced because it is not necessary to maintain the engine speed by the power of the first generator-motor. Therefore, according to the vehicle control device described above, it is possible to extend the running duration of the hybrid vehicle when the engine cannot generate sufficient torque.

Even if the engine cannot generate sufficient torque under certain operating conditions, it may be able to generate sufficient torque under other operating conditions. Therefore, it is preferable that the engine running prohibition control unit in the vehicle control device individually performs the above determination and the prohibition of selection of the engine running mode for each of the plurality of operating regions. In such a case, even if sufficient torque cannot be generated in a specific operating range, the selection of the engine drive mode is permitted in the operating range where sufficient torque can be generated, so that the engine can generate sufficient torque. It is possible to further extend the travelable distance of the vehicle after a state in which it cannot occur.

The plurality of operating regions are classified according to at least one of, for example, engine speed, engine load, engine torque, fuel injection method, implementation of exhaust gas recirculation, and implementation of valve overlap. be able to.

In addition, if it is determined that sufficient torque cannot be generated in more than a certain number of the above operating regions, sufficient torque will be generated even in regions where the same judgment is not currently made. It is highly probable that it will not be possible. Therefore, when the number of operating regions in which the selection of the engine running mode is prohibited exceeds a predetermined value, the engine running prohibition control unit in the vehicle control device prohibits the selection of the engine running mode in all of the plurality of operating regions. It may be prohibited.

If combustion failure occurs in the high-load operating region of the engine, exhaust gas containing a large amount of unburned fuel and oxygen may flow into the catalyst, causing the temperature of the catalyst to become too high. The risk of the occurrence of such poor combustion leading to an excessive rise in the catalyst temperature increases in the operating region on the high-load side. Here, the area where the engine load is equal to or higher than the predetermined value is defined as the latent catalyst overheat area. At this time, the vehicle control device divides the plurality of operating regions according to the engine load, and controls the engine run prohibition control unit to detect that sufficient torque cannot be generated in the operating region within the latent catalyst overheat region. is made, the selection of the engine running mode is prohibited in all of the operating region where the same judgment is made and the operating region on the higher load side than the same operating region. In such a case, selection of the engine running mode is prohibited not only in the operating region where the above determination is made, but also in all operating regions where the risk of causing an excessive rise in catalyst temperature in the event of poor combustion is higher than that operating region. Therefore, an excessive rise in catalyst temperature due to poor combustion is less likely to occur.

In an engine, knock control may be performed to advance the ignition timing to the limit where knocking can be suppressed depending on the occurrence of knocking. When the advance amount of the ignition timing in such knock control is small, the engine is in a state where knocking is likely to occur, that is, the temperature of the exhaust gas is likely to rise. Therefore, in such a case, an excessive increase in catalyst temperature due to poor combustion may occur even in an operating range on the lower load side than usual. Therefore, when the advance amount of the ignition timing by knock control is small, it is preferable to expand the operating region, which is the region within the latent catalyst overheat region, to the lower engine load side than when the advance amount is large.

When a misfire occurs in the engine, unburned air-fuel mixture flows into the catalyst as it is, so the temperature of the catalyst tends to rise excessively. Therefore, the engine run prohibition control unit in the vehicle control device prohibits the selection of the engine run mode in all operating regions within the latent catalyst overheat region when it is confirmed that the engine is misfiring. is desirable.

When there is no area in which the battery can be charged in the driving range where the selection of the engine driving mode is not prohibited, even if the engine driving mode is selected in the driving range where the selection is not prohibited, the driving mode is entirely switched to the EV driving mode, the period during which the driving can be continued does not significantly differ. Therefore, when the above state occurs, selection of the engine running mode may be prohibited in all operating regions.

When starting the engine, if the state in which the torque assist of the first generator-motor is required to increase the engine speed to a predetermined value or more continues for a long time, even if the engine can be started after that, sufficient torque is generated. It is highly likely that it will not be possible. Therefore, when the engine running prohibition control unit in the vehicle control device is in a state in which the torque assist of the first generator motor is required to increase the engine speed to a predetermined value or more when the engine is started, the state continues for a predetermined time or longer, It is preferable to stop the engine start and select the EV driving mode.

The engine run prohibition control unit in the vehicle control device compares a target engine torque, which is a target value of engine torque set according to the running state of the hybrid vehicle and the state of charge in the battery, with the actual value of the engine torque. Based on this, it can be configured to determine whether or not the engine is in a state where it is unable to generate sufficient torque. For example, the above determination can be made using the difference obtained by subtracting the actual value of the engine torque from the target engine torque, or the ratio of the actual value of the engine torque to the target engine torque.

Note that when the target engine torque is set to a value close to zero, it becomes difficult to make an accurate determination based on the above comparison result. Therefore, when the target engine torque is equal to or less than a predetermined value, the engine running prohibition control section in the vehicle control device puts the engine in a state in which it cannot generate sufficient torque because the actual value of the engine torque is equal to or less than a predetermined judgment value. It is desirable to be configured to determine that there is. Also, even if the shaft torque of the engine is close to zero, the indicated torque of the engine, which is the sum of the torque loss due to friction and pumping added to the shaft torque, is a large value to some extent. Therefore, if the indicated torque of the engine is used as the actual value of the engine torque, it is possible to appropriately determine whether or not the engine is in a state where it cannot generate sufficient torque even when the target engine torque is set to a small value. Is possible.

Immediately after the engine is cold-started, catalyst warm-up promotion control may be performed to make the combustion lean and promote the temperature rise of the catalyst. The engine under execution of such catalyst temperature increase promotion control is in a state where it is difficult to generate torque. Therefore, the engine running prohibition control unit in the vehicle control device sets the engine torque threshold for determining that the engine is in a state where it cannot generate sufficient torque when catalyst warm-up promotion control is being performed in the engine. It is desirable to set the value to be larger than when the machine promotion control is not implemented.

It should be noted that there are cases where the state in which the engine cannot generate sufficient torque is temporary and then resolves itself. Even in such a case, immediately prohibiting the selection of the engine running mode will unnecessarily shorten the travelable distance of the vehicle. Therefore, the engine running prohibition control section in the vehicle control device may be configured as follows. That is, when it is determined that the engine is in a state in which it cannot generate sufficient torque, first, an attempt is made to recover the engine torque by increasing the intake air amount of the engine. Then, after that, the same determination is made again, and if it is determined that the engine is in a state where it cannot generate sufficient torque even in the second determination, it is preferable to prohibit selection of the engine running mode.

Further, in the engine, feedback control of engine torque may be performed. For example, in idle speed control, feedback control of engine torque is performed by adjusting the throttle opening based on the deviation between the engine speed during idle operation and the target idle speed. That is, in the idle speed control, when the engine speed is lower than the target idle speed, the throttle opening is increased to increase the engine torque, and when the engine speed is higher than the target idle speed, the throttle is opened. Control is performed to reduce the engine torque by reducing the degree of acceleration. During execution of such feedback control of the engine torque, even if the engine torque temporarily drops, the feedback control may restore the engine torque. Therefore, the engine running prohibition control section in the vehicle control device may be configured as follows. That is, when it is determined that the engine is in a state in which it is not possible to generate sufficient torque while feedback control of the engine torque is not performed in the engine, the feedback control is started to try to recover the engine torque. Then, after the feedback control is started, the same determination is performed again, and when it is determined that the engine is in a state where sufficient torque cannot be generated even by the second determination, selection of the engine running mode is prohibited.

1 is a diagram schematically showing the configuration of a drive system of a hybrid vehicle to which the vehicle control device of the first embodiment is applied; FIG. The figure which shows typically the structure of the control system of the hybrid vehicle. 4 is a flowchart of an engine run prohibition control routine executed by the vehicle control device; The figure which shows the setting aspect of the driving range in the same vehicle control apparatus. 4 is a flowchart of a selection prohibited area setting routine executed by the vehicle control device; 4 is a flowchart of a start-up routine executed by the vehicle control device; 4 is a flowchart of a determination value setting routine executed by a modification of the vehicle control device; The figure which shows typically the structure of a planetary gear mechanism. 10 is a flowchart showing part of the processing procedure of a pinion protection control routine executed by a vehicle control device according to a second embodiment; 4 is a flowchart showing the rest of the processing procedure of the pinion protection control routine;

(First embodiment)
A first embodiment of the vehicle control device will be described in detail below with reference to FIGS. 1 to 6. FIG. Here, first, referring to FIG. 1, the configuration of the drive system of a hybrid vehicle to which the vehicle control system of this embodiment is applied will be described.

As shown in FIG. 1, a hybrid vehicle 10 to which the present embodiment is applied is provided with an engine 11 and two generator-motors, a first generator-motor 12 and a second generator-motor 13, as drive sources. there is A battery 14 is mounted on the hybrid vehicle. The first generator-motor 12 and the second generator-motor 13 function as motors that receive power discharged from the battery 14 to generate power, and function as generators that receive external power and generate power to charge the battery 14. It combines the functions of

Also, in the hybrid vehicle 10, a sun gear 15 as an external gear, a ring gear 16 as an internal gear, and a pinion gear 17A interposed between the sun gear 15 and the ring gear 16 are rotatably supported. A planetary gear mechanism 18 with three rotating elements of the planetary carrier 17 is provided. In such a planetary gear mechanism 18, the rotational speed of two of the three rotating elements determines the rotational speed of the remaining one. The first generator motor 12 is connected to the sun gear 15 of the planetary gear mechanism 18 . Also, the engine 11 is connected to the planetary carrier 17 of the planetary gear mechanism 18 . Further, the ring gear 16 of the planetary gear mechanism 18 is integrally provided with a counter drive gear 19 , and a counter driven gear 20 is meshed with the counter drive gear 19 . A second generator motor 13 is connected to a reduction gear 21 meshed with the counter driven gear 20 .

A final drive gear 22 is connected to the counter driven gear 20 so as to rotate integrally therewith, and a final driven gear 23 is meshed with the final drive gear 22 . Wheel shafts 26 of both wheels 25 are connected to the final driven gear 23 via a differential mechanism 24 .

The first generator motor 12 and the second generator motor 13 are electrically connected to the battery 14 via the inverter 27 . The charge/discharge amount of the battery 14 with respect to the first generator motor 12 and the charge/discharge amount of the battery 14 with respect to the second generator motor 13 are adjusted by the inverter 27 .

FIG. 2 shows the configuration of the control system of the hybrid vehicle 10. As shown in FIG. A control system of the hybrid vehicle 10 is provided with four electronic control units (ECUs): a power management ECU 29 , an engine ECU 30 , a motor ECU 31 , and a battery ECU 32 . The power management ECU 29 performs integrated management of electric power and power of the entire hybrid vehicle 10 , and the engine ECU 30 controls the engine 11 . The motor ECU 31 performs torque control of the first generator motor 12 and the second generator motor 13 , and the battery ECU 32 manages the battery 14 . The vehicle control device of this embodiment is composed of these four electronic control units.

The power management ECU 29 includes various parts of the hybrid vehicle 10, such as a vehicle speed sensor 33 that detects the vehicle speed V of the hybrid vehicle 10, and an accelerator pedal sensor 34 that detects the accelerator pedal opening degree ACC, which is the amount of depression of the accelerator pedal by the driver. The detection results of various sensors provided in are input. Further, the power management ECU 29 receives information indicating the operating conditions of the engine 11 such as the engine speed NE and the engine load KL from the engine ECU 30 . Further, the power management ECU 29 receives input from the motor ECU 31 of a first motor rotation speed NM<b>1 that is the rotation speed of the first generator motor 12 and a second motor rotation speed NM<b>2 that is the rotation speed of the second generator motor 13 . . In addition, the state of charge SOC of the battery 14 and the battery temperature TB, which is the temperature of the battery 14 , are input from the battery ECU 32 to the power management ECU 29 . Note that the state of charge SOC represents the ratio of the amount of charge in the battery 14 to that in the fully charged state.

Based on the input information, the power management ECU 29 calculates a target engine speed NE*, which is a target value for the engine speed NE, and a target engine torque TE*, which is a target value for the engine torque TE. Send to Also, based on the similarly input information, the power management ECU 29 outputs an MG1 command torque TM1* that is a command value for the torque of the first generator-motor 12 and an MG2 command that is a command value for the torque of the second generator-motor 13. A torque TM2* is calculated and transmitted to the motor ECU 31 . The engine ECU 30 controls the operating state of the engine 11 according to the target engine speed NE* and the target engine torque TE*, and the motor ECU 31 controls the inverter 27 according to the MG1 command torque TM1* and the MG2 command torque TM2*. Driving force control of the hybrid vehicle 10 is being performed.

Next, details of calculation processing of the target engine speed NE*, the target engine torque TE*, the MG1 command torque TM1*, and the MG2 command torque TM2* by the power management ECU 29 will be described. The power management ECU 29 calculates a required driving force TP*, which is a required value of the driving force of the hybrid vehicle 10, based on the accelerator pedal opening ACC, the vehicle speed V, and the like. Further, the power management ECU 29 selects one of a plurality of driving modes based on the required driving force TP*, the state of charge SOC of the battery 14, and the like. The plurality of running modes include an engine running mode in which the vehicle runs with the engine 11 running, and an EV running mode in which the vehicle runs with the power of the second generator motor 13 with the engine 11 stopped.

When the EV driving mode is selected, the power management ECU 29 sets the torque of the second generator-motor 13 required for generating the driving force of the required driving force TP* by the second generator-motor 13 alone as the MG2 command torque TM2*. calculated as the value of Also, at this time, the power management ECU 29 calculates zero as the values of the target engine speed NE*, the target engine torque TE*, and the MG1 command torque TM1*. Incidentally, the engine ECU 30 at this time keeps the engine 11 in a stopped state.

On the other hand, the power management ECU 29 calculates the target engine speed NE*, the target engine torque TE*, the MG1 command torque TM1*, and the MG2 command torque TM2* in the following manner when the engine running mode is selected.

That is, when the engine running mode is selected, the power management ECU 29 first calculates the required driving force TP* based on the required driving force TP* and the vehicle speed V while setting the torque of the second generator-motor 13 to zero at the current vehicle speed V. is calculated as the value of the driver requested output PDRV*. Further, the power management ECU 29 at this time calculates a charge/discharge request output PB* based on the state of charge SOC of the battery 14 . In the vehicle control system of this embodiment, the charge/discharge amount of the battery 14 is controlled so that the state of charge SOC of the battery 14 is maintained within a predetermined control target range. For example, when the state of charge SOC is greater than the upper limit value of the control target range, the battery 14 is discharged to the second generator-motor 13, that is, the battery 14 receives the discharged power, and the second generator-motor 13 generates torque. is generated to reduce the state of charge SOC. Further, when the state of charge SOC is less than the lower limit value of the control target range, the battery 14 is charged from the second generator motor 13, that is, the second generator motor 13 generates power and sends power to the battery 14. This increases the state of charge SOC. The required charge/discharge output PB* is calculated as a value obtained by converting the driving force generated by the second generator-motor 13 for such control of the charge/discharge amount into an engine output. Note that the required charge/discharge output PB* is a negative value when the second generator motor 13 generates power using part of the engine output.

Subsequently, the power management ECU 29 at this time calculates the difference obtained by subtracting the charging/discharging required output PB* from the driver required output PDRV* as the value of the required engine output PE*. That is, the engine output required to obtain the required driving force TP* while the charge/discharge amount is being controlled is calculated as the required engine output PE*. Then, the power management ECU 29 obtains an operating point of the engine 11 that can efficiently generate an engine output equivalent to the required engine output PE*, and sets the engine speed NE and the engine torque TE at that operating point to the target engine power. It is calculated as the values of the rotational speed NE* and the target engine torque TE*.

Further, the power management ECU 29 at this time calculates the rotation speed of the first generator-motor 12 required to set the engine rotation speed to the target engine rotation speed NE* as the value of the MG1 target rotation speed NM1*. Then, the power management ECU 29 calculates the value of the MG1 command torque TM1* based on the MG1 target rotation speed NM1*. The calculation of the MG1 command torque TM1* here is performed so as to feedback-control the torque of the first generator-motor 12 based on the deviation of the current rotation speed of the first generator-motor 12 from the MG1 target rotation speed NM1*. there is That is, the sum obtained by adding the feedback correction term according to the deviation to the value of the MG1 command torque TM1* calculated in the previous calculation cycle is obtained as the value of the MG1 command torque TM1* in the current calculation cycle. .

Also, at this time, the power management ECU 29 determines the torque transmitted from the engine 11 to the counter driven gear 20 in a state where the first generator motor 12 is generating the torque equivalent to the MG1 command torque TM1* as the direct torque TEQ. calculated as the value of Then, the power management ECU 29 controls the torque of the second generator-motor 13 to obtain the driving force of the required driving force TP* in a state where the torque corresponding to the direct torque TEQ is transmitted from the engine 11 to the counter driven gear 20. is calculated as the value of the MG2 command torque TM2*.

Now, when the above-described engine running mode is selected, combustion failure may occur due to a malfunction of the engine 11, and the engine 11 may be unable to generate the engine torque TE for the value of the target engine torque TE*. When the engine running mode is selected, even in such a state, the torque control of the first generator motor 12 is performed so that the engine speed NE becomes the target engine speed NE*. As long as power supply to electric motor 12 continues, hybrid vehicle 10 can continue to run in the engine running mode. However, in such a case, electric power is used to maintain the engine speed NE, and the state of charge SOC of the battery 14 decreases more quickly, shortening the period during which the vehicle can continue running.

On the other hand, in the vehicle control apparatus of the present embodiment, by performing the following engine run prohibition control, the duration of running of the hybrid vehicle 10 after the engine 11 becomes unable to generate sufficient torque is extended. ing.

FIG. 3 shows a flowchart of an engine running prohibition control routine executed by the power management ECU 29 for engine running prohibition control as described above. The power management ECU 29 repeatedly executes the processing of this routine at regular control cycles while the engine running mode is being selected. In the vehicle control system of this embodiment, the power management ECU 29 that executes such engine run prohibition control is configured to correspond to the engine run prohibition control unit.

When the processing of this routine is started, first, in step S100, it is determined whether or not the target engine torque TE* is a value exceeding the predetermined value A. When the target engine torque TE* exceeds the default value A (YES), the process proceeds to step S110, and when the target engine torque TE* is equal to or less than the default value A (NO). , the process proceeds to step S120.

When the process proceeds to step S110, it is determined in step S110 whether or not the difference obtained by subtracting the actual value of the engine torque from the target engine torque TE* is equal to or greater than a predetermined determination value B. If the difference is greater than or equal to the judgment value B (YES), the process proceeds to step S130, and if the difference is less than the judgment value B (NO), the current routine is terminated. When the actual value of the engine torque falls significantly below the target engine torque TE*, the value of the difference increases. Therefore, in step S110, it is determined that the engine 11 cannot generate sufficient torque because the difference obtained by subtracting the actual value of the engine torque from the target engine torque TE* is equal to or greater than the predetermined determination value B. there is

As described above, in the engine running mode, feedback control of the torque of the first generator-motor 12 is performed to maintain the engine speed NE at the target engine speed NE*. The shaft torque of the engine 11 can be calculated from the value of . Therefore, in the present embodiment, the value of the shaft torque of the engine 11 calculated from the MG1 command torque TM1* is used as the actual value of the engine torque used for determination in step S110 and step S120 below.

On the other hand, when the process proceeds to step S120, it is determined whether or not the actual value of the engine torque is equal to or less than the predetermined determination value C in step S120. If the actual value of the engine torque is less than or equal to the judgment value C (YES), the process proceeds to step S130. Processing of the routine is terminated. When a small torque close to zero is set as the target engine torque TE*, the actual value of the shaft torque of the engine 11 can be calculated from the target engine torque TE* even if the engine 11 cannot generate sufficient torque. may not be a value greater than or equal to the default value A. Therefore, in the present embodiment, when a small torque equal to or less than the default value A is set as the value of the target engine torque TE*, the actual value of the engine torque is equal to or less than the default value C, so that the engine 11 can operate sufficiently. It is determined that it is in a state where torque cannot be generated.

If it is determined in step S110 or step S120 that the engine 11 cannot generate sufficient torque and the process proceeds to step S130, in step S130, the engine ECU 30 is instructed to increase the torque to increase the engine torque. Enforcement of controls is commanded. As the torque raising control, the intake air amount of the engine 11 is increased. Further, the engine ECU 30 executes feedback control of engine torque as part of engine control. For example, in idle speed control, feedback control of engine torque is performed by adjusting the throttle opening based on the deviation between the engine speed NE during idle operation and the target idle speed. That is, in the idle speed control, when the engine speed is lower than the target idle speed, the throttle opening is increased to increase the engine torque, and when the engine speed is higher than the target idle speed, the throttle is opened. Control is performed to reduce the engine torque by reducing the degree of acceleration. In a situation where the feedback control of the engine torque can be executed, if the feedback control is not executed, the execution of the feedback control is commanded as the torque raising control. As described above, in this embodiment, when it is determined that the engine 11 is in a state in which it cannot generate sufficient torque, the torque boost control is performed to attempt to recover the reduced engine torque.

After that, in step S140, it is determined whether or not the engine torque has been recovered by the execution of the torque raising control. Then, if the engine torque has recovered (YES), the processing of this routine ends as it is, and if it has not recovered (NO), the processing proceeds to step S150. The determination of whether or not the engine torque is recovered in step S140 is performed in the same manner as in steps S100 to S120.

When the process proceeds to step S150, a prohibited area setting process is performed in step S150. After the execution, the processing of this routine is terminated. In the prohibited area setting process, a process of determining an operating area in which selection of the engine running mode is prohibited from among a plurality of operating areas divided according to the operating state of the engine 11 is performed.

As shown in FIG. 4, in the vehicle control system of this embodiment, eight operating regions R1 to R8 are set according to the engine speed NE and the engine load KL. After calculating the target engine speed NE* and the target engine torque TE* at the time of selection of the engine running mode, the power management ECU 29 determines that the operating point of the engine 11 indicated by these calculated values is the same as that of the selected engine running mode. If the operating point is within the prohibited operating range, the operation of the engine 11 is stopped and the travel mode is switched to the EV travel mode.

When combustion failure occurs in the engine 11, exhaust containing a large amount of unburned fuel and excess oxygen flows into an exhaust purification catalyst installed in the exhaust passage. Then, the unburned fuel reacts with the surplus oxygen in the catalyst to raise the temperature of the catalyst. In the high-load operating range of the engine 11, the catalyst temperature may rise beyond the allowable maximum temperature due to poor combustion. In the following description, an operating region where the catalyst temperature may become too high due to poor combustion is referred to as a latent catalyst overheating region. In FIG. 4, the extent of the latent catalyst overheating region is indicated by hatching. As shown in the figure, among the eight operating regions, three operating regions R6 to R8 on the high load side are located within the latent catalyst overheat region.

On the other hand, the engine ECU 30 performs knock control as part of engine control. In knock control, the ignition timing is advanced to the limit where knocking can be suppressed based on the occurrence of knocking. More specifically, in the knock control, the KCS retardation amount, which is the ignition timing retardation amount from the optimum ignition timing, which is the ignition timing at which the torque generation efficiency of the engine 11 is maximized, is determined by adjusting the KCS retardation amount without confirming the occurrence of knocking. It gradually decreases at times and increases when the occurrence of knocking is confirmed, thereby advancing the ignition timing to the limit where knocking can be suppressed. When the ignition timing is retarded from the optimum ignition timing, the heat loss of the engine 11 increases and the temperature of the exhaust gas rises. Therefore, when the KCS retardation amount is increased in knock control, the catalyst temperature rises. Therefore, in the present embodiment, when the KCS retardation amount is set to a value larger than the default value, the latent catalyst overheat region is expanded so that the operating region R5 is included in addition to the operating regions R6 to R8. ing. That is, in the present embodiment, when the advance amount of the ignition timing by knock control is small, the operating region, which is the region within the latent catalyst overheat region, is expanded to the lower engine load side than when the ignition timing advance amount is large. ing.

FIG. 5 shows a flowchart of a prohibited area setting routine executed by the power management ECU 29 in the prohibited area setting process. The processing of this routine is executed by the power management ECU 29 as the processing of step S130 of the above-described engine run prohibition control routine.

When the processing of this routine is started, first, in step S200, the selection of the engine running mode in the current operating region is prohibited. In this manner, selection of the engine running mode is prohibited in the operating region during operation when it is determined that the engine 11 cannot generate sufficient torque.

Subsequently, in step S210, it is determined whether a misfire has occurred in the engine 11 or not. When it is determined that a misfire has occurred (YES), the process proceeds to step S220, and when it is determined that a misfire has not occurred (NO), the process proceeds to step S230. be done. The engine ECU 30 determines whether or not a misfire has occurred based on the variation pattern of the engine speed NE, and notifies the power management ECU 29 of the determination result. The determination in step S210 is made based on the determination result of the occurrence of misfire notified by the engine ECU 30 .

If the occurrence of a misfire has been confirmed and the process proceeds to step S220, in step S220, after prohibiting the selection of the engine running mode in all the operating regions R5 to R8 within the latent catalyst overheat region. , the process proceeds to step S250. When it is confirmed that a misfire has occurred in this way, selection of the engine running mode is prohibited in all operating regions within the latent catalyst overheat region in addition to the operating region currently being operated. .

On the other hand, if the occurrence of a misfire has not been confirmed and the process proceeds to step S230, it is determined in step S230 whether or not the current operating region is within the latent catalyst overheating region. be done. If the operating region currently being operated is within the latent catalyst overheat region (YES), in step S240, the engine running mode can be selected in all of the operating regions on the higher load side than the operating region currently being operated. After being prohibited, the process proceeds to step S250. On the other hand, if the current operating region is not within the latent catalyst overheating region (NO), the process proceeds directly to step S250.

When the process proceeds to step S250, it is determined in step S250 whether or not there is an operating range in which the battery 14 can be charged in the operating range in which the selection of the engine running mode is not prohibited. be. Then, if such an operating region exists (YES), the processing of this routine is terminated as it is. After the selection is prohibited, the processing of this routine ends.

Although omitted in the above flow chart, when the number of operating regions in which the selection of the engine running mode is prohibited exceeds a certain number, the selection of the engine running mode is prohibited in all the operating regions R1 to R8. are doing. This is to prevent the engine 11 from operating in such a state because there is a high possibility that some serious problem has occurred in the engine 11 when the torque is reduced in a wide operating range. .

By the way, in the hybrid vehicle 10 , the engine 11 is rotated by the torque of the first generator motor 12 to start the engine 11 . The rotation maintenance of the engine 11 by the torque of the first generator-motor 12 in such a start, that is, the cranking is continued until the engine 11 reaches a state capable of self-sustaining operation. If there is a problem with the intake system, ignition system, fuel system, etc. of the engine 11 and poor combustion occurs, the period of cranking will become longer. In such a case, even if the start-up of the engine 11 is completed, the fuel shortage continues after that, and it is likely to be in a state where sufficient torque cannot be generated. In such a case, the vehicle control device of the present embodiment prohibits selection of the engine running mode by the above-described engine running prohibition control and shifts to the EV running mode. becomes. On the other hand, the power management ECU 29 in the vehicle control system of the present embodiment executes the processing of the following startup routine in order to suppress unnecessary power consumption in such a case.

FIG. 5 shows a flow chart of the startup routine. The power management ECU 29 repeatedly executes the processing of this routine at each predetermined control cycle during the period from the start of the engine 11 to the completion or cancellation thereof.

When the processing of this routine is started, first, in step S400, it is determined whether or not the elapsed time from the start of cranking has reached a predetermined determination value E or more. The judgment value E is set to a value that is slightly longer than the estimated maximum time required for the completion of cranking when the engine 11 is functioning properly. Then, if the elapsed time is less than the judgment value E (NO), the processing of this routine is terminated as it is. On the other hand, if the elapsed time is equal to or greater than the judgment value E (YES), that is, if the starting of the engine 11 is not completed before the elapsed time reaches the judgment value E, the process proceeds to step S310. . Then, in step S310, the starting of the engine 11 is stopped and the running mode is switched to the EV running mode, after which the processing of this routine ends.

The operation of this embodiment will be described.
The hybrid vehicle 10 to which the vehicle control device of the present embodiment is applied has an engine running mode in which the engine 11 is running and an EV running by the power of the second generator motor 13 with the engine 11 stopped. It is possible to run in a running mode. During the operation of the engine 11 in the engine running mode, the engine 11 may be in a state where sufficient torque cannot be generated due to poor combustion caused by malfunctions in the intake system, the ignition system, the fuel system, or the like. In the following description, this state is referred to as a torque reduction state.

In the hybrid vehicle 10 to which the vehicle control device of the present embodiment is applied, the first generator-motor 12 supports the rotation of the engine 11 even when the engine 11 is in a torque reduction state. As long as power supply to the generator motor 12 can be continued, it is possible to continue running in the engine running mode. However, in such a state, electric power is used to cause the second generator-motor 13 to generate the driving force that is insufficient due to a decrease in the torque of the engine 11, and the first generator-motor 12 is used to maintain the rotation of the engine 11. power supply is also required. Therefore, in such a case, it is better to stop the engine 11 and switch to running in the EV running mode than to continue running the engine 11 in the torque reduced state and continue running in the engine running mode. The period during which you can continue running becomes longer.

Therefore, when it is confirmed that the engine 11 is in a torque reduction state, the power management ECU 29 in the vehicle control system of the present embodiment prohibits the selection of the engine running mode in the operating region during operation at that time. As a result, an unnecessary increase in electric power consumption due to the operation of the engine 11 in a state of reduced torque is suppressed.

When combustion failure occurs in the engine 11 , unburned fuel and oxygen flow into a catalyst installed in the exhaust passage of the engine 11 . Then, the inflowing fuel and oxygen react within the catalyst to raise the temperature of the catalyst. In the high-load operating range of the engine 11, if combustion failure occurs, the catalyst temperature may rise beyond the allowable maximum temperature. The higher the engine load, the higher the possibility that the catalyst temperature will rise excessively due to such poor combustion. Further, when a torque reduction state is confirmed in a certain operating region, there is a possibility that some trouble has occurred in the engine 11, and it is conceivable that poor combustion will occur in other operating regions as well.

On the other hand, in the present embodiment, the high-load operating range, in which the catalyst temperature may excessively rise due to poor combustion, is set as the latent catalyst overheat range. Then, when a torque reduction state is confirmed in the operating region within the latent catalyst overheat region, in addition to the confirmed operating region, the engine running mode is selected in all of the higher load side operating regions. is prohibited. Therefore, excessive temperature rise of the catalyst due to poor combustion is less likely to occur.

On the other hand, in the engine 11, feedback control of ignition timing is performed by knock control. When the ignition timing is retarded by such knock control, the temperature of the exhaust gas and, by extension, the temperature of the catalyst increase. On the other hand, in the present embodiment, when the advance amount of the ignition timing by knock control is small, the operating region, which is the region within the latent catalyst overheat region, is shifted to the lower engine load side than when the ignition timing advance amount is large. expanding.

Furthermore, when the combustion state of the engine 11 deteriorates and a misfire occurs, the air-fuel mixture introduced into the combustion chamber flows directly into the catalyst, so the catalyst temperature rises more easily than in the case of poor combustion that does not lead to misfire. . Therefore, in this embodiment, when it is confirmed that a misfire has occurred in the engine 11, selection of the engine running mode is prohibited in all operating regions within the latent catalyst overheat region.

As described above, in this embodiment, the range of the operating region in which the selection of the engine running mode is prohibited when confirming the torque reduction state is determined according to the risk of excessive temperature rise of the catalyst. Therefore, it is possible to effectively suppress the occurrence of excessive temperature rise of the catalyst due to poor combustion.

Note that even when it is confirmed that the engine 11 is in a state of reduced torque, the state may be temporary and then spontaneously resolved. Even in such a case, immediately prohibiting the selection of the engine driving mode unnecessarily shortens the period during which driving can be continued. On the other hand, in this embodiment, when a torque reduction state is confirmed, first, an attempt is made to restore the engine torque by increasing the intake air amount or implementing torque feedback control. And, when the engine torque is not recovered even by the implementation thereof, the selection of the engine running mode is prohibited.

Note that in the present embodiment, when the target engine torque TE* is a value exceeding the default value A, the engine 11 is in a torque reduction state based on the result of comparison between the target engine torque TE* and the actual value of the engine torque. It is determined whether or not there is Further, in the present embodiment, the shaft torque of the engine 11 calculated from the MG1 command torque TM1* or the like is used as the actual value of the engine torque. Even in such a case, if the target engine torque TE* is set to a value larger than a certain value, the difference between the target engine torque TE* and the actual value of the engine torque will increase to some extent when the engine 11 is in a torque reduction state. Since it becomes a large value, it can determine accurately. However, when a small torque near zero is set as the target engine torque TE*, even if the shaft torque of the engine 11 becomes zero due to a misfire, the difference between the target engine torque TE* and the actual value of the engine torque is large. Therefore, it may not be possible to appropriately determine the torque reduction state from the above comparison result. In contrast, in the present embodiment, when a small torque equal to or less than the predetermined value A is set as the target engine torque TE*, determination is made based on whether the actual value of the engine torque is equal to or less than the determination value C. ing. Therefore, even when a small torque close to zero is set as the target engine torque TE*, it can be accurately determined that the engine 11 is in a torque reduction state.

It should be noted that, among the operating regions R1 to R8 of the engine 11, there are regions where the battery 14 can hardly be charged. On the other hand, as a result of the engine running prohibition control, there may be no operating range in which the battery 14 can be charged in the operating range in which the selection of the engine running mode is not prohibited. In such a case, even if the engine 11 is operated in an operating range in which the selection is not prohibited, electric power is only consumed. There is not much difference in the period during which the running can be continued. On the other hand, in the case as described above, there is a high possibility that some problem has occurred in the engine 11, and if the engine 11 continues to operate in such a state, the problem may become worse. Therefore, in the vehicle control device of the present embodiment, when there is no region in which the battery 14 can be charged in the operating regions in which the selection of the engine running mode is not prohibited, the engine running mode is selected in all the operating regions. selection is prohibited, and the vehicle is driven only in the EV driving mode.

(Modified example of the first embodiment)
Immediately after the engine 11 is cold-started, combustion is performed at an air-fuel ratio leaner than the stoichiometric air-fuel ratio to increase the temperature of the exhaust gas, thereby promoting the activation of the catalyst for purifying the exhaust gas. may be executed. When such catalyst temperature increase acceleration control is executed, combustion becomes slower than when combustion is performed at the stoichiometric air-fuel ratio, and engine torque is less likely to be generated. Therefore, even if there is no problem with the engine 11, it may be erroneously determined that the engine 11 is in a torque reduction state during execution of the catalyst temperature increase acceleration control. Such an erroneous determination can be suppressed by changing the determination values B and C of the torque decrease state depending on whether or not the catalyst temperature increase promotion control is executed.

FIG. 7 shows a flow chart of a determination value setting routine for changing the values of the determination values B and C depending on whether or not the catalyst temperature increase promotion control is executed. The processing of this routine is executed by the power management ECU 29 prior to execution of the engine running prohibition control routine shown in FIG. When the processing of this routine is started, first, in step S400, it is determined whether or not the catalyst temperature increase acceleration control is being executed. If the catalyst temperature increase acceleration control is not being executed (NO), the predetermined value B1 is set as the judgment value B, and the predetermined value C1 is set as the judgment value C, in step S410. On the other hand, if the catalyst temperature increase acceleration control is being executed (YES), in step S420, a predetermined value B2 larger than the value B1 is set as the determination value B, and a predetermined value smaller than the value C1 is set. is set as the value of the judgment value C, respectively.

In such a case, the engine torque threshold at which it is determined that the engine 11 is in the low torque state is a smaller value during execution of the catalyst temperature increase promotion control than when it is not executed. Therefore, it is possible to appropriately determine the low torque state of the engine 11 even during the execution of the catalyst temperature increase promotion control in which engine torque is difficult to generate.

Furthermore, this embodiment can be implemented with the following modifications. This embodiment and the following modified examples can be implemented in combination with each other within a technically consistent range.
In the above embodiment, when it is determined that the engine 11 is in a torque reduction state, the torque increase control is performed by increasing the amount of intake air and implementing the torque feedback control, and the torque reduction state is not resolved even after the implementation. In this case, selection of the engine running mode is prohibited. As the torque raising control at this time, control other than increasing the amount of intake air or performing torque feedback control may be employed.

- When it is determined that the engine 11 is in the torque reduction state, the engine running mode may be immediately prohibited without executing the torque increase control.
In the above embodiment, the determination of the torque reduction state when the target engine torque TE* exceeds the predetermined value A is performed based on the difference obtained by subtracting the actual value of the engine torque from the target engine torque TE*. Such determination may be made based on the ratio of the actual value of the engine torque to the target engine torque TE*. The ratio of the actual value of the engine torque to the target engine torque TE* is a value close to 1 when the engine 11 is not in the torque reduction state, and is a positive value smaller than 1 when the engine 11 is in the torque reduction state. Become. Therefore, a positive value smaller than 1 can be set as the determination value, and it can be determined that the engine 11 is in the torque reduction state when the ratio is equal to or less than the determination value. Even in such a case, the torque reduction state is determined based on the result of comparison between the target engine torque TE* and the actual value of the engine torque.

In the above embodiment, when the target engine torque TE* is equal to or less than the predetermined value A, it is determined that the engine 11 is in the torque reduction state because the actual value of the engine torque is equal to or less than the determination value C. Even when the target engine torque TE* is equal to or less than the default value A, similarly to when the target engine torque TE* exceeds the default value A, the torque reduction state is determined based on the result of comparison between the target engine torque TE* and the actual value of the engine torque. You may do so.

- In the above embodiment, the shaft torque of the engine 11 calculated from the MG1 command torque TM1* or the like is used as the actual value of the engine torque when determining the torque reduction state. An indicated torque obtained by adding the torque loss inside the engine 11 due to pumping or friction to the shaft torque may be obtained, and the obtained value may be used as the actual value of the engine torque to determine the torque decrease state. Even when the shaft torque of the engine 11 has a value close to zero, the indicated torque has a relatively large value. Therefore, in such a case, even when a small torque in the vicinity of zero is set as the target engine torque TE*, the torque reduction state is determined based on the result of comparison between the target engine torque TE* and the actual value of the engine torque. be able to do it accurately.

- The processing of the startup routine may be omitted.
In the above embodiment, when there is no battery chargeable region in the operating regions where the selection of the engine driving mode is not prohibited, the engine driving mode is selected in all the operating regions R1 to R8. was prohibited. As long as there is an operating region in which the selection of the engine running mode is not prohibited without performing such processing, the operation of the engine 11 may be permitted in such a region.

In the above embodiment, when the number of operating regions in which the selection of the engine driving mode is prohibited reaches a certain number, the selection of the engine driving mode is prohibited in all the driving regions R1 to R8. As long as there is an operating region in which the selection of the engine running mode is not prohibited without performing such processing, the operation of the engine 11 may be permitted in such a region.

・In the above embodiment, when it is confirmed that a misfire has occurred, the selection of the engine running mode is prohibited in all operating regions within the latent catalyst overheat region, but such processing may be omitted. good.

In the above-described embodiment, when it is determined that the engine 11 is in a torque reduction state in the operating region within the latent catalyst overheat region, in addition to the operating region in which the same determination is made, a higher load side than the operating region Although the selection of the engine running mode is prohibited in all of the operating regions, such processing may be omitted.

In the above embodiment, the operation regions R1 to R8, which are units for determining the torque reduction state and prohibiting the selection of the engine driving mode, were divided according to the engine speed NE and the engine torque TE. The operating regions may be classified using parameters other than those that indicate the operating state. Such parameters include engine load, fuel injection method, whether exhaust gas recirculation is implemented, and whether valve overlap is implemented.

In the above embodiment, the determination of the torque reduction state and the prohibition of the selection of the engine running mode are performed for each of a plurality of operating regions, but these may be performed collectively for the entire operating region of the engine 11.

The hybrid vehicle 10 to which the vehicle control device of the above embodiment is applied has the first generator motor 12 in the sun gear 15 of the planetary gear mechanism 18, the engine 11 in the planetary carrier 17, and the second generator motor 13 in the ring gear 16. and the wheel axle 26 were respectively connected. The vehicle control device of the embodiment is similarly applicable to a hybrid vehicle in which the combination of the engine 11, the first generator-motor 12, the second generator-motor 13, and the rotating elements of the planetary gear mechanism 18 to which they are connected is different. can do.

(Second embodiment)
Next, a second embodiment of the vehicle control device will be described in detail with reference to FIGS. 8 to 10 as well. In addition, in this embodiment, the same reference numerals are given to the configurations common to those of the above-described embodiment, and detailed description thereof will be omitted.

Conventionally, as seen in Patent Document 1, an engine and two generator-motors, a first generator-motor and a second generator-motor, are provided as drive sources for running, and three rotations of a sun gear, a planetary carrier, and a ring gear are provided. Hybrid vehicles provided with a planetary gear mechanism having elements are known. A planetary carrier in the planetary gear mechanism rotatably supports a pinion gear meshed with both the sun gear and the ring gear. The sun gear of the planetary gear mechanism is connected to the engine, the planetary carrier is connected to the first generator-motor, and the ring gear is connected to the second generator-motor and the wheel shaft.

In the planetary gear mechanism, the rotation speed of the pinion gear is determined by the relationship between the rotation speeds of the three rotating elements. In a hybrid vehicle provided with such a planetary gear mechanism, drive control of the engine and the generator motor is performed so that the rotation speed of the pinion gear does not exceed the allowable maximum rotation speed. However, if an engine malfunction occurs and the engine speed cannot be properly controlled, the pinion gear speed will exceed the allowable maximum speed, and the pinion gear bearings in the planetary carrier will There is a possibility that the durability of the component parts of the planetary gear mechanism, such as a planetary gear mechanism, may deteriorate.

The vehicle control device of the present embodiment performs pinion protection control for protecting the planetary gear mechanism from deterioration in durability due to such excessive rotation of the pinion gear. The configurations of the drive system and control system of the hybrid vehicle 10 to which the vehicle control system of the present embodiment is applied are the same as those in the first embodiment shown in FIGS. 1 and 2. FIG. Further, the vehicle control device of this embodiment controls the driving force of the hybrid vehicle 10 in the same manner as in the first embodiment.

As shown in FIG. 8, in the following description, the rotation speed of the planetary carrier 17 in the planetary gear mechanism 18 is the carrier rotation speed NC, the rotation speed of the ring gear 16 is the ring gear rotation speed NR, and the pinion gear on the planetary carrier 17 is The rotation speed of 17A is described as pinion difference rotation speed NP. The number of gear teeth of the pinion gear 17A is "ZP", and the number of gear teeth of the ring gear 16 is "ZR". At this time, the relationship of formula (1) holds between the carrier rotational speed NC, the pinion differential rotational speed NP, and the ring gear rotational speed NR. In the hybrid vehicle 10, the output shaft of the engine 11 is connected to the planetary carrier 17 so as to rotate together, and the engine speed NE is equal to the carrier speed NC (NE=NC).

ここで、遊星ギア機構１８の構成部品の耐久性により定まるピニオン差回転数ＮＰの許容最大値を許容最大差回転数ＮＰＭＡＸとする。ここで、ピニオンギア１７Ａのギア歯の数ＺＰに対するリングギア１６のギア歯の数ＺＲの比（ＺＰ／ＺＲ）を「γ」とおくと、リングギア回転数ＮＲを任意に変化させたときのピニオン差回転数ＮＰが許容最大差回転数ＮＰＭＡＸ以下となるエンジン回転数ＮＥの範囲の最大値ＭＡＸ及び最小値ＭＩＮは、それぞれ式（２）及び式（３）の関係を満たす値となる。

Here, the allowable maximum value of the pinion differential rotation speed NP determined by the durability of the components of the planetary gear mechanism 18 is defined as the allowable maximum differential rotation speed NPMAX. Here, if the ratio (ZP/ZR) of the number ZR of gear teeth of the ring gear 16 to the number ZP of gear teeth of the pinion gear 17A is "γ", the number of gear teeth when the ring gear rotation speed NR is arbitrarily changed. The maximum value MAX and minimum value MIN of the range of the engine speed NE in which the pinion differential speed NP is equal to or less than the allowable maximum differential speed NPMAX are values that satisfy the relationships of formulas (2) and (3), respectively.

よって、エンジン回転数ＮＥが最小値ＭＩＮから最大値ＭＡＸまでの範囲内に収まっていれば、ピニオン差回転数ＮＰを許容最大差回転数ＮＰＭＡＸ以下とすることができる。なお、リングギア回転数ＮＲは、第２発電電動機１３の回転数である第２モータ回転数ＮＭ２と、カウンタドライブギア１９、カウンタドリブンギア２０、及びリダクションギア２１のそれぞれのギア歯の数から計算して求めることができる。

Therefore, if the engine speed NE is within the range from the minimum value MIN to the maximum value MAX, the pinion difference speed NP can be made equal to or less than the allowable maximum difference speed NPMAX. Note that the ring gear rotation speed NR is calculated from the second motor rotation speed NM2, which is the rotation speed of the second generator motor 13, and the number of gear teeth of each of the counter drive gear 19, the counter driven gear 20, and the reduction gear 21. can be asked for.

As described above, the power management ECU 29 calculates the target engine speed NE* when controlling the driving force of the hybrid vehicle 10 . The calculation of the target engine speed NE* at this time is performed so that the pinion differential speed NP is within the range of the engine speed NE in which the allowable maximum differential speed NPMAX or less. That is, the target engine speed NE* is calculated so as to be lower than the maximum value MAX and higher than the minimum value MIN.

9 and 10 show a flowchart of a pinion protection control routine executed by the power management ECU 29 for pinion protection control. While the engine 11 is running, the power management ECU 29 repeatedly executes the processing of the same routine at each predetermined control cycle. In the vehicle control system of this embodiment, the power management ECU 29 that executes the processing of such a pinion protection control routine corresponds to the pinion protection control section.

When the processing of this routine is started, first, in step S500, the ring gear rotation speed NR is calculated from the second motor rotation speed NM2. Furthermore, in step S500, based on the calculated ring gear rotation speed NR, the maximum value MAX and the minimum value MIN are calculated as values that satisfy the above-described equations (2) and (3).

Subsequently, in step S510, the maximum value MAX is set as the value of the first threshold value NEP1, and the minimum value MIN is set as the value of the third threshold value NEP3. Further, in step S510, the difference obtained by subtracting the default value F from the maximum value MAX is set as the value of the second threshold value NEP2, and the sum of the minimum value MIN plus the default value G is set as the value of the fourth threshold value NEP4.

In subsequent step S520, it is determined whether or not the engine speed NE is greater than or equal to the second threshold value NEP2. Then, if the engine speed NE is equal to or greater than the second threshold value NEP2 (YES), the process proceeds to step S530, and if it is less than the second threshold value NEP2 (NO), the process proceeds to step S600. When the engine speed NE is equal to or greater than the second threshold value NEP2 and the process proceeds to step S530, the engine ECU 30 is commanded to stop the fuel injection of the engine 11 in step S530, and then the process proceeds to step S540. be advanced.

When the process proceeds to step S540, it is determined in step S540 whether or not the engine speed NE is greater than or equal to the first threshold value NEP1. If the engine speed NE is greater than or equal to the first threshold value NEP1 (YES), the process proceeds to step S550, and if it is less than the first threshold value NEP1 (NO), the process proceeds to step S560. When the engine speed NE is equal to or greater than the first threshold value NEP1 and the process proceeds to step S550, after the engine ECU 30 is commanded to stop the ignition of the engine 11 in step S550, the process proceeds to step S560. be done.

The power management ECU 29 sets the target engine speed NE* to be less than the first threshold value NEP1. Therefore, when the engine speed NE is equal to or higher than the first threshold value NEP1, there is a possibility that the engine 11 has a problem such as the throttle valve being stuck open. On the other hand, when the process proceeds to step S600, it is determined whether or not it is confirmed that a problem has occurred in the engine 11 that causes an excessive increase in the engine speed NE and that the problem is not temporary. That is, it is determined whether or not the above problem continues thereafter. Here, if it is determined that the malfunction will not continue (NO), the processing of this routine ends as it is. On the other hand, if it is determined that the problem continues (YES), the current routine processing is terminated after the driving mode is switched to the EV driving mode in step S560. That is, at this time, the operation of the engine 11 is stopped and the restart of the engine 11 is prohibited.

On the other hand, when it is determined in step S520 that the engine speed NE is less than the second threshold value NEP2 and the process proceeds to step S600, it is determined whether the engine 11 is idling in step S600. is determined. If the vehicle is idling (YES), the process proceeds to step S610, and if it is not idling (NO), the processing of this routine ends. During the idle operation of the engine 11, the engine ECU 30 performs idle speed control for feedback-controlling the throttle opening so that the engine speed NE becomes the target idle speed. Note that, during normal idling, the shaft torque zero rotation speed, which is the engine rotation speed NE at which the shaft torque of the engine 11 becomes zero, is set as the target idle rotation speed.

When the engine 11 is idling and the process proceeds to step S610, it is determined in step S610 whether or not the engine speed NE is equal to or lower than the fourth threshold value NEP4. If the engine speed NE is equal to or less than the fourth threshold value NEP4 (YES), the process proceeds to step S620, and if it exceeds the fourth threshold value NEP4 (NO), the process of this routine ends. be done. If the engine speed NE is equal to or less than the fourth threshold value NEP4 and the process proceeds to step S620, in step S620, the value of the zero shaft torque speed or the fourth threshold value NEP4, whichever is greater, is determined. After the other value is set as the target idling speed, the process proceeds to step S630.

When the process proceeds to step S630, it is determined in step S630 whether or not the engine speed NE is equal to or lower than the third threshold value NEP3. If the engine speed NE is equal to or less than the third threshold value NEP3 (YES), the process proceeds to step S640, and if it exceeds the third threshold value NEP3 (NO), the process of this routine ends. be done. When the engine speed NE is equal to or lower than the third threshold value NEP3 and the process proceeds to step S640, it is determined in step S640 whether or not the power running operation of the first generator motor 12 is possible. A situation in which power running operation of the first generator-motor 12 is not possible includes, for example, a case where the state of charge SOC of the battery 14 is lowered and power cannot be supplied to the first generator-motor 12, or a case where the temperature of the first generator-motor 12 is It may be too high.

When the power running operation of the first generator motor 12 is possible (S640: YES), the process proceeds to step S650, and feedback control of the engine speed NE by the first generator motor 12 is performed in step S650. After that, the processing of this routine is terminated. In the feedback control performed at this time, feedback control of the MG1 command torque TM1* is performed so as to increase the engine speed NE to a speed exceeding the third threshold value NEP3.

On the other hand, if the power running operation of the first generator-motor 12 is not possible (S640: NO), the process proceeds to step S660. , the processing of this routine is terminated. The engine ECU 30 normally cuts fuel when the intake air amount of the engine 11 is reduced to the misfire range, but when an instruction to prohibit fuel cut is issued, the engine ECU 30 suspends the fuel cut even in such a case. .

The operation of this embodiment will be described.
As described above, in the vehicle control system of the present embodiment, the target engine speed NE* is set as a value within the range of the engine speed NE in which the pinion differential speed NP is equal to or less than the allowable maximum differential speed NPMAX. Therefore, if the engine 11 is appropriately controlled so that the engine speed NE is maintained at the target engine speed NE*, the pinion differential speed NP will not exceed the allowable maximum differential speed NPMAX. . However, if the engine 11 has a problem such as a stuck open throttle valve that inhibits a decrease in engine torque, the engine speed NE may increase beyond the target engine speed NE*.

In the vehicle control device of the present embodiment, fuel injection of the engine 11 is stopped when the engine speed NE reaches or exceeds the second threshold value NEP2. Note that the ignition of the engine 11 is continued at this point. Therefore, even if the fuel injected just before the fuel injection is stopped remains in the combustion chamber, the remaining fuel will be burned. As described above, the second threshold value NEP2 is set to a rotation speed lower than the maximum value MAX of the range of the engine rotation speed NE at which the pinion differential rotation speed NP is less than the allowable maximum differential rotation speed NPMAX by the predetermined value F. In this embodiment, the default value F is set to a value larger than the assumed maximum value of the amount of increase in the engine speed NE due to the combustion of residual fuel. Therefore, even if the residual fuel in the combustion chamber burns and the engine speed NE rises somewhat, the pinion difference speed NP does not reach the allowable maximum difference speed NPMAX.

Thereafter, when the engine speed NE further increases and reaches the first threshold value NEP1, ignition of the engine 11 is stopped in addition to fuel injection. Therefore, when the engine speed NE reaches the first threshold value NEP1, combustion in the engine 11 is immediately stopped regardless of whether or not unburned fuel remains in the combustion chamber. As described above, the first threshold value NEP1 is set to the maximum value MAX of the range of the engine speed NE in which the pinion differential speed NP is less than the allowable maximum differential speed NPMAX.

As described above, in the present embodiment, when the engine speed NE excessively increases due to a malfunction of the engine 11 or the like, the engine 11 Stops fuel injection while continuing ignition. At this time, the fuel injected immediately before stopping the fuel injection may remain in the combustion chamber, but since the ignition continues, the remaining fuel will be burned. As a result, unburned fuel is directly discharged into the exhaust passage, and the temperature of the exhaust purification catalyst installed in the exhaust passage rises. can be avoided. On the other hand, when the engine speed NE increases until the pinion differential speed NP reaches the allowable maximum differential speed NPMAX, ignition is stopped in addition to fuel injection. combustion is immediately stopped. Therefore, it is possible to suppress an increase in the pinion differential rotation speed NP exceeding the allowable maximum differential rotation speed NPMAX while suppressing discharge of unburned fuel into the exhaust passage.

Note that if a problem such as a stuck open throttle valve occurs in the engine 11 that hinders a decrease in engine torque, even if the engine speed NE is reduced by stopping fuel injection or ignition, combustion will occur after that. is resumed, the engine speed NE will increase. Therefore, when it is confirmed that such a problem of the engine 11 continues thereafter, the driving mode is switched to the EV driving mode so that the engine 11 is not operated.

By the way, as described above, when the engine 11 is under load, feedback control of the torque of the first generator-motor 12 is performed to maintain the engine speed NE at the target engine speed NE*. On the other hand, as described above, the target engine speed NE* is set to be higher than the minimum value MIN of the range of the engine speed NE at which the pinion differential speed NP is equal to or less than the allowable maximum differential speed NPMAX. ing. Therefore, during load operation of the engine 11, even if there is a problem with the engine 11, as long as the feedback control of the torque of the first generator-motor 12 is properly performed, the engine speed NE remains at the minimum value MIN. The pinion differential rotation speed NP does not exceed the allowable maximum differential rotation speed NPMAX. However, during the idle operation of the engine 11, the engine 11 maintains its rotational speed by itself through idle speed control. Therefore, during idling, if there is a problem with the engine 11, the engine speed NE may drop below the minimum value MIN and the pinion differential speed NP may exceed the allowable maximum differential speed NPMAX.

On the other hand, in the vehicle control device of the present embodiment, when the engine speed NE drops below the fourth threshold value NEP4 during idling of the engine 11, the greater one of the zero shaft torque speed and the fourth threshold value NEP4 is set as the target idle speed value, which is the target value of the engine speed for idle speed control. Thus, the engine speed NE is maintained at the fourth threshold value NEP4.

However, if there is a problem with the engine 11, the idle speed control may not be able to maintain the engine speed NE, resulting in a further decrease in the engine speed NE. As described above, the fourth threshold value NEP4 is set to a speed higher than the minimum value MIN of the range of the engine speed NE at which the pinion difference speed NP is equal to or less than the allowable maximum difference speed NPMAX by the predetermined value G. Therefore, at this time, a slight decrease in the engine speed NE is still acceptable.

On the other hand, when the engine speed NE decreases to the third threshold value NEP3 and the pinion difference speed NP reaches the allowable maximum difference speed NPMAX, the first generator motor 12 is operated to increase the engine speed NE to the third threshold value NEP3 or more. Torque feedback control is started. Therefore, even if the engine 11 has a problem and the engine 11 cannot suppress the decrease in the engine speed NE by itself, it is possible to suppress the increase in the pinion differential speed NP exceeding the allowable maximum differential speed NPMAX.

Note that feedback control of the torque of the first generator-motor 12 at this time may not be possible due to a decrease in the state of charge SOC of the battery 14, overheating of the first generator-motor 12, or the like. On the other hand, in the engine 11, during normal operation, when the amount of intake air decreases to an amount at which normal combustion cannot be performed, that is, when the amount of intake air decreases to a misfire range, fuel cut is performed to suppress the discharge of unburned fuel into the exhaust passage. . In the vehicle control device of the present embodiment, when the engine speed NE drops to the third threshold value NEP3 or less and the power running operation of the first generator motor 12 cannot be performed, that is, the feedback control of the torque of the first generator motor 12 Fuel cut is prohibited when the engine speed NE cannot be maintained. As a result, combustion is continued as much as possible even if the intake air amount drops to the misfire range, thereby suppressing the decrease in the engine speed NE as much as possible.

As described above, in the vehicle control system of the present embodiment, when the engine speed NE decreases during idling, the idling is started while the pinion difference speed NP is lower than the allowable maximum difference speed NPMAX. Through speed control, the engine speed NE of the engine 11 is maintained by itself. When the engine speed NE drops until the pinion differential speed NP reaches the allowable maximum differential speed NPMAX, the torque assist of the first generator motor 12 is used to maintain the engine speed NE. As described above, in the present embodiment, the engine 11 is made to suppress the increase in the pinion differential rotation speed NP to the allowable maximum differential rotation speed NPMAX due to the decrease in the engine rotation speed NE without consuming electric power as much as possible. ing. Therefore, it is possible to suppress an increase in power consumption for suppressing an excessive increase in the pinion differential rotation speed NP.

This embodiment can be implemented with the following modifications. This embodiment and the following modified examples can be implemented in combination with each other within a technically consistent range.
In the above embodiment, when the engine speed NE becomes equal to or less than the third threshold value NEP3 during idling and the power running operation of the first generator-motor 12 becomes impossible, the fuel cut of the engine 11 is prohibited. However, processing other than prohibition of fuel cut may be performed.

・In the above embodiment, the driving mode is switched to the EV driving mode when it is confirmed that the failure of the engine 11 that hinders the decrease of the engine torque will continue, but the engine driving mode is continued even in such a case. You may make it

If the engine speed NE does not drop until the pinion differential speed NP reaches the allowable maximum differential speed NPMAX even during idling, the processing after step S600 in the pinion protection control routine is omitted. may

Technical ideas that can be grasped from the above embodiment and modifications will be described.
(b) Three rotations of a sun gear connected to an engine, a ring gear connected to a wheel shaft, and a planetary carrier having a pinion gear meshed with both the sun gear and the ring gear and connected to a generator motor. In a vehicle control device applied to a hybrid vehicle having a planetary gear mechanism having elements, the number of rotations of the pinion gear on the planetary carrier is increased based on the number of rotations of the wheel shaft and the number of rotations of the generator motor. The maximum value of the engine speed range that is equal to or less than a predetermined value is calculated as a first threshold, and the engine speed lower than the first threshold is calculated as a second threshold, and the engine speed is equal to or higher than the second threshold. a pinion protection control unit that stops fuel injection of the engine when the engine speed becomes equal to or higher than the first threshold value, and stops ignition of the engine when the engine speed becomes equal to or greater than the first threshold value.

In the vehicle control device described above, fuel injection is stopped while ignition of the engine is continued while the rotational speed of the pinion gear is lower than the predetermined value. At this time, the fuel injected immediately before the fuel injection is stopped may remain in the combustion chamber of the engine, but the ignition is continued, so the remaining fuel is burned. As a result, unburned fuel is directly discharged into the exhaust passage, and the temperature of the exhaust purification catalyst installed in the exhaust passage rises. can be avoided. On the other hand, when the engine speed increases until the pinion gear speed reaches a predetermined value, ignition is stopped in addition to fuel injection, so engine combustion is immediately stopped regardless of the presence or absence of residual fuel in the combustion chamber. be. Therefore, it is possible to suppress an excessive increase in the rotational speed of the pinion gear while suppressing discharge of unburned fuel into the exhaust passage.

(b) The pinion protection control unit stops the operation of the engine and prohibits restarting of the engine when it is confirmed that the engine continues to have a problem that causes an excessive increase in the engine speed. The vehicle control device according to (b) above.

Even if the engine speed is lowered by stopping fuel injection or ignition, if the problem causing the excessive increase in the engine speed continues, the engine speed will rise again when combustion is restarted. Therefore, in such a case, it is desirable to stop the operation of the engine and prohibit the engine from restarting.

(C) The engine performs idle speed control, which is feedback control of an intake air amount for setting the engine speed to a target idle speed, during idle operation, and the pinion protection control unit controls the wheel Higher than the third threshold, which is the minimum value of the engine speed range at which the pinion gear speed is equal to or less than the predetermined value based on the shaft speed and the generator motor speed. The engine speed is calculated as a fourth threshold, and when the engine speed is equal to or lower than the fourth threshold during idling of the engine, the target idle speed is set to be equal to or higher than the fourth threshold. and performing drive control of the generator motor so that the engine speed exceeds the third threshold when the engine speed falls below the third threshold during idling of the engine, or The vehicle control device according to (b).

In the above vehicle control device, when the engine speed decreases during idling, while the speed of the pinion gear is lower than the predetermined value, the engine speed is controlled by the engine itself through idle speed control. We are trying to maintain Then, when the engine speed decreases until the pinion gear speed reaches a predetermined value, the engine speed is maintained by drive control of the first generator-motor. As described above, in the vehicle control device, the engine itself suppresses an excessive increase in the rotation speed of the pinion gear due to a decrease in the engine rotation speed as much as possible without consuming electric power. Therefore, it is possible to suppress an increase in power consumption for suppressing an excessive increase in the rotational speed of the pinion gear.

(d) prohibiting fuel cut of the engine when the engine speed is equal to or lower than the third threshold value during idling of the engine and power running operation of the generator-motor becomes impossible; Vehicle controller as described.

In the vehicle control device described above, when a decrease in engine speed cannot be suppressed by drive control of the generator motor, engine combustion continues even in a situation in which fuel cut should be performed. decrease in

DESCRIPTION OF SYMBOLS 10... Hybrid vehicle, 11... Engine, 12... 1st generator motor, 13... 2nd generator motor, 14... Battery, 15... Sun gear, 16... Ring gear, 17... Planetary carrier, 17A... Pinion gear, 18... Planetary gear Mechanism, 19... Counter drive gear, 20... Counter driven gear, 21... Reduction gear, 22... Final drive gear, 23... Final driven gear, 24... Differential mechanism, 25... Wheel, 26... Wheel shaft, 27... Inverter, 29...Engine run prohibition control section, power management ECU as a pinion protection control section, 30...Engine ECU as a learning control section, 31...Motor ECU, 32...Battery ECU, 33...Vehicle speed sensor, 34...Accelerator pedal sensor.

Claims (14)

An engine, two generator motors of a first generator motor and a second generator motor, a planetary gear mechanism having three rotating elements of a sun gear, a ring gear, and a planetary carrier, the first generator motor and the second generator a battery that stores electric power generated by the electric motor and supplies the stored electric power to the first generator-motor and the second generator-motor, the engine being one of the three rotating elements; The first generator-motor is connected to one of the two, and the second generator-motor and the wheel shaft are connected to the last one. One of a plurality of driving modes including an engine driving mode in which operation of the engine is stopped and an EV driving mode in which driving is performed by the power of the second generator-motor with the engine stopped, is selected to drive the hybrid vehicle. In a vehicle control device that performs travel control,
It is determined whether or not the engine is in a state in which sufficient torque cannot be generated, and when it is determined that it is in a state in which sufficient torque cannot be generated, an engine running prohibition control unit that prohibits selection of the engine running mode prepared ,
The engine running prohibition control unit individually performs the determination and the prohibition of selection of the engine running mode for each of a plurality of operating regions divided according to the operating state of the engine.
Vehicle controller. The plurality of operating regions are divided according to at least one of engine speed, engine load, engine torque, fuel injection method, whether or not exhaust gas recirculation is performed, and whether or not valve overlap is performed. Item 1. The vehicle control device according to item 1 . The engine running prohibition control unit prohibits selection of the engine running mode in all of the plurality of operating regions when the number of operating regions in which selection of the engine running mode is prohibited exceeds a predetermined value. The vehicle control device according to claim 1 or 2 . When a region in which the engine load is equal to or greater than a predetermined value is defined as the latent catalyst overheat region, the plurality of operating regions are divided according to the engine load, and the engine running prohibition control unit controls operation within the latent catalyst overheat region. When it is determined that sufficient torque cannot be generated in an area, the engine running mode is selected in all of the operating area in which the determination is made and the operating area on the higher load side than the operating area. The vehicle control device according to any one of claims 1 to 3, which is prohibited. In the engine, knock control is performed to advance the ignition timing to the limit where knocking can be suppressed according to the occurrence of knocking. 5. The vehicle control system according to claim 4 , wherein the operating region within the latent catalyst overheating region is expanded to a lower engine load side than when is large. 5. The engine running prohibition control unit prohibits selection of the engine running mode in all operating regions within the latent catalyst overheat region when it is confirmed that a misfire has occurred in the engine. 6. The vehicle control device according to 5 . When there is no region in which the battery can be charged among operating regions in which selection of the engine running mode is not prohibited, selection of the engine running mode is prohibited in all operating regions . The vehicle control device according to claim 6 . The engine running prohibition control unit suspends the engine starting and enters the EV running mode when a state in which the torque assist of the first generator motor is required to maintain rotation of the engine continues for a predetermined time or longer at the time of starting the engine. 8. The vehicle control device according to any one of claims 1 to 7, wherein the vehicle travels by The engine running prohibition control unit performs a comparison between a target engine torque, which is a target value of the engine torque set according to the running condition of the hybrid vehicle and the charging condition of the battery, and the actual value of the engine torque. The vehicle control device according to any one of claims 1 to 8, wherein it is determined whether or not the engine is in a state in which it cannot generate sufficient torque. When the target engine torque is equal to or less than a predetermined value, the engine running prohibition control unit determines that the engine is in a state where sufficient torque cannot be generated because the actual value of the engine torque is equal to or less than a predetermined determination value. The vehicle control device according to claim 9 . 11. A vehicle control system according to claim 9, wherein indicated torque of said engine is used as the actual value of said engine torque. When catalyst warm-up promotion control is being performed in the engine, the engine running prohibition control unit sets a threshold value of engine torque for determining that the engine is in a state in which sufficient torque cannot be generated by the catalyst warm-up promotion control. 12. The vehicle control device according to any one of claims 1 to 11, wherein the value is set to be larger than when it is not implemented. When it is determined that the engine cannot generate sufficient torque, the engine running prohibition control unit increases the intake air amount of the engine and makes the same determination again. 13. The vehicle control device according to any one of claims 1 to 12, wherein selection of the engine running mode is prohibited when it is determined that the engine is in a state where sufficient torque cannot be generated. When it is determined that the engine is in a state in which the engine cannot generate sufficient torque while feedback control of the engine torque is not being performed in the engine, the engine running prohibition control unit starts the feedback control. The same determination is made again in , and if it is determined that the engine is in a state where sufficient torque cannot be generated even in the second determination , selection of the engine running mode is prohibited. Vehicle controller as described.

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