Vehicle control device

Abstract

To suppress slowness of acceleration of a hybrid vehicle under a low atmospheric pressure environment.SOLUTION: An electronic control unit 30 controls a throttle opening of an engine 11 upon completion of coupling a system clutch 15, according to atmospheric pressure, so that a constant intake air quantity can be obtained regardless of whether the atmospheric pressure is high or low, in switching from electrically-driven traveling of traveling in a state that the system clutch 15 is disconnected and the engine 11 is stopped, to hybrid traveling of traveling in a state that the system clutch 15 is coupled and the engine 11 is operated.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a vehicle control device that controls a hybrid vehicle.

Background Art

[0002] As a hybrid vehicle, there is a vehicle equipped with a hybrid system in which an engine and a power generation motor are connected via a clutch, and the rotating shaft of the power generation motor is used as a power take-out shaft. The driving modes of a hybrid vehicle equipped with such a hybrid system include the following two modes. One is an electric driving mode in which the engine is stopped and the clutch is disengaged, and the vehicle runs by the power of the power generation motor. The other is a hybrid driving mode in which the vehicle runs with the clutch engaged. In such a hybrid vehicle, the electric driving mode is used when the vehicle is stopped or running at low speed. When the driver steps on the accelerator pedal to request vehicle acceleration, the driving mode is switched from the electric driving mode to the hybrid driving mode.

[0003] As a vehicle control device for controlling such a hybrid vehicle, the device described in Patent Document 1 is known. The vehicle control device of this document switches the driving mode from the electric driving mode to the hybrid driving mode in the following procedure. First, while the vehicle is running in the electric driving mode, the engine is started while rotating the engine with the power of the power generation motor with the clutch in a slip state. Next, when the engine becomes capable of self-rotation, the engagement force of the clutch is temporarily reduced. Then, when the engine speed has increased until the power generation motor and the engine rotate synchronously, the clutch is reconnected to complete the switch to the hybrid driving mode.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] When the clutch is re - engaged, in order to suppress the torque step, it is desirable to throttle the throttle opening to keep the engine torque near "0". And after the clutch is re - engaged, it is desired to rapidly increase the engine torque for vehicle acceleration.

[0006] By the way, in highlands where the atmospheric pressure is low, the intake air volume of the engine obtained at the same throttle opening is less than that in lowlands. Therefore, in an environment of low atmospheric pressure such as highlands, the increase in engine torque after clutch re - engagement is delayed. As a result, there is a risk that the vehicle occupants will feel poor acceleration.

Means for Solving the Problems

[0007] The vehicle control device for solving the above problems is a device for controlling a hybrid vehicle having a hybrid system including an engine and a power - generating motor as a power source. The hybrid system has a clutch interposed between the output shaft of the engine and the rotating shaft of the power - generating motor, and is a system having the rotating shaft of the power - generating motor as a power take - out shaft. Also, the hybrid vehicle has an electric driving mode in which the engine is stopped and the clutch is disengaged, and a hybrid driving mode in which the clutch is engaged. And the vehicle control device controls the throttle opening of the engine when the connection of the clutch is completed at the time of switching from the electric driving mode to the hybrid driving mode according to the atmospheric pressure so that the opening is larger when the atmospheric pressure is low than when the atmospheric pressure is high.

[0008] In the above hybrid vehicle, when acceleration exceeding the capacity of the power generation motor is required, the driving mode is switched to the hybrid driving mode, and after the clutch is fully engaged, the engine torque is increased to meet the acceleration requirement. When the intake air volume of the engine at the time of complete clutch engagement is small, the subsequent increase in engine torque is delayed compared to when the intake air volume is large. On the other hand, when the atmospheric pressure is low, the intake air volume of the engine obtained at the same throttle opening is less than when the atmospheric pressure is high. Therefore, if the throttle opening at the time of complete clutch engagement is constant, the intake air volume of the engine at the start of acceleration is less when the atmospheric pressure is low than when the atmospheric pressure is high. As a result, the increase in engine torque is delayed and the acceleration of the hybrid vehicle becomes sluggish.

[0009] In that regard, in the above vehicle control device, when the atmospheric pressure is low, the throttle opening at the time of complete clutch engagement is made larger than when the atmospheric pressure is high. Therefore, the intake air volume of the engine when the engine torque increases, that is, the engine torque at the start of acceleration, is less likely to change depending on the high or low atmospheric pressure. Accordingly, the above vehicle control device makes it less likely for the acceleration of the hybrid vehicle to become sluggish under low atmospheric pressure.

[0010] It is desirable that the above vehicle control device be configured to set the throttle opening when the clutch engagement is completed to an opening at which the intake air volume of the engine is a constant amount with respect to the atmospheric pressure. In such a case, the intake air volume of the engine when starting to increase the engine torque after the clutch engagement is completed becomes a constant amount regardless of the atmospheric pressure. Therefore, the acceleration performance of the hybrid vehicle is less likely to change depending on the high or low atmospheric pressure.

[0011] Furthermore, when switching from the electric driving mode to the hybrid driving mode, it is desirable that the above vehicle control device control the torque of the power generation motor so that the torque output by the hybrid system increases at a constant gradient during the period from the restart of the engine to the command to increase the torque of the engine in response to the driving requirement of the hybrid vehicle.

[0012] By controlling the torque of the power generation motor as described above, it becomes possible to smoothly increase the output torque of the hybrid vehicle until the start of the increase in the engine torque according to the driving request. When the engine torque changes due to the atmospheric pressure, it becomes difficult to realize such an increase in the output torque. If the increase gradient of the torque is set within a feasible range even when the atmospheric pressure is low, the increase in the output torque will be delayed and the acceleration performance of the hybrid vehicle will be restricted. In this regard, in the above vehicle control device, since the engine torque can be ensured regardless of the high or low atmospheric pressure, such problems are less likely to occur.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Best Mode for Carrying Out the Invention

[0014] Hereinafter, an embodiment of the vehicle control device will be described in detail with reference to FIGS. 1 to 7. <Configuration of Drive System of Hybrid Vehicle> First, with reference to FIG. 1, the configuration of the drive system of the hybrid vehicle controlled by the vehicle control device of the present embodiment will be described. The hybrid vehicle includes a hybrid system 10 as a power source. The hybrid system 10 includes an engine 11, a power generation motor 12, and a system clutch 15. The hybrid system 10 includes the rotation shaft of the power generation motor 12 as the power take-out shaft of the hybrid system 10. The system clutch 15 is interposed between the crankshaft 13, which is the output shaft of the engine 11, and the system output shaft 14. And the system clutch 15 disconnects and connects the crankshaft 13 and the system output shaft 14. Further, the hybrid system 10 includes an inverter 16 and a battery 17. The inverter 16 controls the amount of power transmitted between the power generation motor 12 and the battery 17.

[0015] In addition, a transmission 20 is provided in the hybrid vehicle. The transmission 20 includes a torque converter 21 and a transmission mechanism 22. The system output shaft 14 of the hybrid system 10 is connected to the transmission input shaft 23, which is the input shaft of the transmission mechanism 22, via the torque converter 21. The transmission mechanism 22 changes the rotation of the transmission input shaft 23 and transmits it to the wheels of the hybrid vehicle. Further, the transmission 20 is provided with a lock-up clutch 24 that can directly connect the system output shaft 14 and the transmission input shaft 23 without passing through the torque converter 21.

[0016] <Configuration of Vehicle Control Device> Subsequently, with reference to FIG. 2, the configuration of the vehicle control device of the present embodiment will be described. The vehicle control device includes an electronic control unit 30. The electronic control unit 30 has an arithmetic processing unit 31 that executes various processes for vehicle control, and a storage device 32 that stores control programs and data.

[0017] The electronic control unit 30 receives detection signals from various sensors provided in each part of the hybrid vehicle. Such sensors include an air flow meter 33, an atmospheric pressure sensor 34, an intake pressure sensor 35, a crank angle sensor 36, an accelerator pedal sensor 37, and a vehicle speed sensor 38. The air flow meter 33 is a sensor that detects the intake air flow rate GA of the engine 11. The atmospheric pressure sensor 34 is a sensor that detects the atmospheric pressure PA. The intake pressure sensor 35 is a sensor that detects the intake pressure PM of the engine 11. The crank angle sensor 36 is a sensor that detects the crank angle CRNK, which is the rotational phase of the crankshaft 13 of the engine 11. The accelerator pedal sensor 37 is a sensor that detects the accelerator pedal operation amount ACC of the driver of the hybrid vehicle. The vehicle speed sensor 38 is a sensor that detects the vehicle speed V of the hybrid vehicle. Note that the electronic control unit 30 calculates the engine speed, which is the rotational speed of the crankshaft 13 of the engine 11, from the detection result of the crank angle sensor 36.

[0018] Then, the electronic control unit 30 controls the hybrid system 10 based on the detection results of those sensors. For example, the electronic control unit 30 controls the operating state of the engine 11 by operating actuators provided in the engine 11, such as the throttle valve 39, the injector 40, and the ignition device 41. Also, the electronic control unit 30 performs torque control of the power generation motor 12 through the control of the inverter 16. Furthermore, the electronic control unit 30 controls the system clutch 15. In the following description, the opening degree of the throttle valve 39 is referred to as the throttle opening TA.

[0019] <Driving Modes of Hybrid Vehicle> The hybrid vehicle has two driving modes: an electric driving mode and a hybrid driving mode. The electric driving mode is a driving mode in which the engine 11 is stopped and the system clutch 15 is disengaged. The hybrid driving mode is a driving mode in which the engine 11 is operating and the system clutch 15 is engaged. In the following description, the driving of the hybrid vehicle in the electric driving mode is referred to as electric driving. Also, the driving of the hybrid vehicle in the hybrid driving mode is referred to as hybrid driving.

[0020] During electric driving, the electronic control unit 30 calculates a required driving torque based on the accelerator pedal operation amount ACC, vehicle speed V, etc. The required driving torque represents the required value of the system shaft torque necessary for the driving of the hybrid vehicle. Also, the system shaft torque represents the torque transmitted from the system output shaft 14 of the hybrid system 10 to the transmission 20. Then, the electronic control unit 30 controls the inverter 16 so as to supply the power necessary for generating the torque corresponding to the required driving torque from the battery 17 to the generator motor 12.

[0021] On the other hand, during hybrid driving, the electronic control unit 30 calculates the required driving torque in the same manner as during electric driving. Further, during hybrid driving, the electronic control unit 30 calculates a battery required torque based on the charge amount of the battery 17. The electronic control unit 30 controls the charge and discharge amount of the battery 17 so as to maintain the charge amount of the battery 17 within a predetermined range. The battery required torque represents the required value of the torque to be generated in the generator motor 12 for the control of such charge and discharge amount. Next, the electronic control unit 30 calculates the difference obtained by subtracting the battery required torque from the required driving torque as the value of the required engine torque, which is the required value of the engine torque. Then, the electronic control unit 30 controls the opening degree of the throttle valve 39 of the engine 11 so as to obtain the intake air amount necessary for generating the torque corresponding to the required engine torque. Also, the electronic control unit 30 controls the inverter 16 so that the generator motor 12 generates the torque corresponding to the battery required torque.

[0022] <Control for Switching from Electric Driving to Hybrid Driving> Based on the vehicle speed V, accelerator pedal operation amount ACC, charge amount of the battery 17, etc., the electronic control unit 30 switches the driving mode. Here, the details of the control for switching from electric driving to hybrid driving will be described. During electric driving, when the required driving torque increases to near the maximum MG torque, the electronic control unit 30 interrupts the electric driving and starts hybrid driving. The maximum MG torque represents the maximum value of the torque that the motor generator 12 can generate. The maximum MG torque is a value determined by the charge amount of the battery 17 and the MG rotation speed. The MG rotation speed represents the rotation speed of the motor generator 12, that is, the rotation speed of the system output shaft 14. The maximum MG torque decreases as the charge amount of the battery 17 decreases. Also, the maximum MG torque decreases as the MG rotation speed increases. Further, when the charge amount of the battery 17 falls below a certain value during electric driving, the electronic control unit 30 also interrupts the electric driving and starts hybrid driving.

[0023] Next, the details of the control for switching from electric driving to hybrid driving will be described. As described above, during electric driving, the hybrid system 10 has the engine 11 stopped and the system clutch 15 disengaged. When a switch from electric driving to hybrid driving is requested, the electronic control unit 30 first starts connecting the system clutch 15. When the connection of the system clutch 15 is started, the connecting force between the crankshaft 13 and the system output shaft 14 by the system clutch 15 gradually increases. Then, the engine 11 enters a cranking state where the crankshaft 13 is rotated by the torque of the motor generator 12. When the engine rotation speed rises above a certain value due to cranking, the electronic control unit 30 starts fuel injection and ignition to restart the engine 11. The electronic control unit 30 restarts the engine 11 with the throttle opening TA set to the default starting opening. After the restart of the engine 11 and the connection of the system clutch 15 are completed, the electronic control unit 30 starts hybrid driving.

[0024] The switch from electric driving to hybrid driving is often carried out when the hybrid vehicle starts or accelerates. Therefore, when switching to hybrid driving, it is required to quickly increase the system shaft torque to ensure the acceleration performance of the hybrid vehicle.

[0025] Here, referring to FIG. 3, consider the control design of the hybrid system 10 to reduce the jerk during acceleration when switching from electric driving to hybrid driving. FIG. 3(a) shows the transition of the engine speed and the MG speed when switching from electric driving to hybrid driving. FIG. 3(b) shows the transition of the commanded value and the actual value of the engine torque at the time of the same switch. Further, FIG. 3(c) shows the transition of the commanded value and the maximum value of the system shaft torque at the time of the same switch. In FIG. 3(c), the transition of the maximum MG torque when the switch from electric driving to hybrid driving is required in a state where the charge amount of the battery 17 has reached the minimum amount that permits electric driving is also shown. Note that the transitions of the respective parameters shown in FIG. 3 are those of a comparative example for comparison with the vehicle control device of the present embodiment.

[0026] In the case of FIG. 3, the connection of the system clutch 15 is started at time t0. Then, from time t1 thereafter, the increase in the engine speed by cranking is started. At time t2, the engine 11 is restarted. Further, at time t3 thereafter, the synchronous rotation of the engine 11 and the generator motor 12 is started and the connection of the system clutch 15 is completed.

[0027] When the engine 11 generates torque at the time of connecting the system clutch 15, a torque step occurs. Therefore, after the restart of the engine 11, until time t3 when the connection of the system clutch 15 is completed, it is necessary to maintain the engine torque near "0" by retarding the ignition timing or the like. The state where the engine torque is "0" is a state where the engine 11 generates the minimum necessary torque for self-sustained operation.

[0028] Also, when the engine 11 is restarted, the catalyst for exhaust purification is in an inactive state. And it takes a certain amount of time to activate the catalyst. Therefore, in order to ensure the emissions of the engine 11 until a certain amount of time has passed after the restart, an increase in engine torque in response to the driving requirements of the hybrid vehicle cannot be permitted. In the case of FIG. 3, the activation of the catalyst is completed at time t5. The electronic control unit 30 commands an increase in engine torque in response to the driving requirements from that time t5. Note that there is a delay in the increase in engine torque. Therefore, in the case of FIG. 3, the increase in engine torque in response to the command at time t5 starts from time t6.

[0029] The maximum value of the system shaft torque achievable by the hybrid system 10 is the value obtained by subtracting the cranking torque from the maximum MG torque during the period until the time t3 when the connection of the system clutch 15 is completed. The cranking torque represents the torque of the power generation motor 12 consumed for the rotation of the engine 11. After the restart of the engine 11, the cranking torque decreases as the engine torque increases. On the other hand, after time t3, the value obtained by adding the engine torque to the maximum MG torque becomes the maximum value of the system shaft torque achievable by the hybrid system 10.

[0030] In Fig. 3(c), the range of the impossible system shaft torque is shown by hatching. Until time t2, in order to ensure the cranking torque, the system shaft torque can hardly be increased. On the other hand, after time t6, the system shaft torque can be increased by the engine torque. Therefore, if the system shaft torque is increased along the line segment A - B in Fig. 3(c) during the period from time t2 to time t6, smooth and rapid acceleration becomes possible. That is, the command value of the system shaft torque at time t2 when the engine 11 starts to generate torque is set to a value T1 slightly smaller than the value obtained by subtracting the maximum value of the cranking torque from the maximum MG torque at that time. Also, the command value of the system shaft torque at time t6 when the increase in the engine torque starts is set to a value T2 slightly smaller than the maximum MG torque at that time. Then, during the period from time t2 to time t6, the command value of the system shaft torque is set to a value that increases at a constant gradient from the value T1 at time t2 to the value T2 at time t6. The electronic control unit 30 controls the torque of the power generation motor 12 so that the system shaft torque corresponding to the command value can be obtained.

[0031] By setting the command value of the system shaft torque as described above when switching from electric driving to hybrid driving, the hybrid vehicle can be accelerated smoothly and rapidly. However, during highland driving, there is a risk that the system shaft torque is insufficient and the acceleration of the hybrid vehicle becomes sluggish.

[0032] FIG. 4(a) shows the transition of the commanded value of the engine torque, and the actual values of the engine torque in the lowland and highland, during the period after time t3 in FIG. 3. FIG. 4(b) shows the transition of the commanded value of the system shaft torque, the maximum value of the achievable system shaft torque in each of the lowland and highland, and the actual value of the system shaft torque in the highland, during the same period. Further, FIG. 4(b) also shows the transition of the maximum MG torque. Since the atmospheric pressure PA is low in the highland, even if the throttle opening TA is the same, the intake air amount of the engine 11 is less than that in the lowland. Therefore, in the highland, the engine torque around time t5 is smaller than that in the lowland. As a result, in the highland, the system shaft torque around time t5 may fall below the commanded value. Here, the highland and lowland represent the high and low atmospheric pressure PA of the environment in which the hybrid vehicle is traveling, and do not necessarily coincide with the high and low altitude. Here, the lowland represents a place where the atmospheric pressure PA is the standard atmospheric pressure, and the highland represents a place where the atmospheric pressure PA is lower than the standard atmospheric pressure.

[0033] <Throttle Opening Control at Restart> The electronic control unit 30 performs throttle opening control at restart to suppress the jerk during acceleration in such a highland. The details of such throttle opening control at restart will be described below.

[0034] FIG. 5 shows a flowchart of the throttle opening control at restart. The electronic control unit 30 controls the throttle opening TA in the procedure shown in FIG. 5 during the period from when the restart of the engine 11 for switching from electric driving to hybrid driving is requested until the start of normal throttle opening control. Here, the normal throttle opening control is the control of the throttle opening TA according to the driving request, which is performed after the activation of the catalyst is completed.

[0035] When the electronic control unit 30 requests a restart of the engine 11, it sets the throttle opening TA to the starting opening as shown in step S100. After that, the electronic control unit 30 holds the throttle opening TA at the starting opening until the catalyst becomes in a partially active state (S110: YES). The state where the catalyst is partially active means that the catalyst is activated to such an extent that it can purify a small amount of exhaust gas. Note that the electronic control unit 30 determines that the catalyst is partially active when the elapsed time from the restart of the engine 11 reaches a predetermined partial activity determination value. A time shorter than the predicted value of the time required from the restart of the engine 11 until the connection of the system clutch 15 is completed is set as the partial activity determination value.

[0036] When the catalyst becomes in a partially active state, the electronic control unit 30 calculates a fixed intake air amount opening TACON based on the atmospheric pressure PA in step S120. The fixed intake air amount opening TACON represents the throttle opening TA required to make the intake air amount of the engine 11 a fixed amount. A value that satisfies both of the following requirement 1 and requirement 2 is set as the intake air amount to be the fixed amount. Requirement 1 is that the exhaust gas amount when the engine 11 is operated at that intake air amount is an amount that the catalyst in the partially active state can purify. Requirement 2 is that when the system clutch 15 is connected in the state where the engine 11 is operated at that intake air amount, the torque shock generated by the connection is within an allowable range. Then, the electronic control unit 30 sets the calculated fixed intake air amount opening TACON to the throttle opening TA in step S130.

[0037] Fig. 6 shows the relationship between the atmospheric pressure PA and the fixed intake air amount opening TACON. As shown in Fig. 6, the fixed intake air amount opening TACON is set to be a larger opening when the atmospheric pressure PA is low than when the atmospheric pressure PA is high.

[0038] Thereafter, the electronic control unit 30 holds the throttle opening TA at the fixed intake air opening TACON until the activation of the catalyst is completed (S140: YES). Then, when the activation of the catalyst is completed, the electronic control unit 30 ends the throttle opening control at the time of restart and starts the normal throttle opening control. Note that the electronic control unit 30 determines that the activation of the catalyst is completed when the elapsed time after the restart of the engine 11 reaches the predetermined activation completion determination value. A time longer than the predicted value of the time required from the restart of the engine 11 until the connection of the system clutch 15 is completed is set as the activation completion determination value. Therefore, the throttle opening TA at the time of the completion of the connection of the system clutch 15 is set to the fixed intake air opening TACON.

[0039] <Operational effects of the embodiment> The operation and effects of this embodiment will be described. FIG. 7(a) shows the transition of the engine speed and the MG speed at the time of switching from electric running to hybrid running in this embodiment. FIG. 7(b) shows the transition of the command value and the actual value of the engine torque at the time of the same switching in this embodiment. Further, FIG. 7(c) shows the transition of the command value and the maximum value of the system shaft torque at the time of the same switching in this embodiment. Note that the transition of the maximum MG torque is also shown in FIG. 7(c). Also in the case of FIG. 4, similar to the case of FIG. 3, the connection of the system clutch 15 starts at time t0, and the increase in the engine speed due to cranking starts at time t1. Further, the engine 11 is restarted at time t2, and the connection of the system clutch 15 is completed at time t3. Furthermore, in the case of FIG. 4, the activation of the catalyst is completed at time t4, and the electronic control unit 30 commands an increase in the engine torque according to the running request at that time t4. Note that the actual engine torque increases according to the command at time t4 from the subsequent time t5.

[0040] When the time t23 is earlier than the time t3 when the connection of the system clutch 15 is completed, the electronic control unit 30 changes the throttle opening TA of the engine 11 from the starting opening to the constant intake air amount opening TACON when the catalyst is in a partially warmed-up state. As described above, the constant intake air amount opening TACON is calculated based on the atmospheric pressure PA as the throttle opening TA at which the intake air amount of the engine 11 becomes a predetermined amount X. Therefore, the intake air amount of the engine 11 at the time t4 when increasing the engine torque according to the driving request becomes a constant amount regardless of the level of the atmospheric pressure PA. That is, regardless of the level of the atmospheric pressure PA, the engine torque at the time t4 becomes constant. Therefore, even on highlands where the atmospheric pressure PA is low, the system shaft torque does not fall below the command value around the time t5.

[0041] According to the above-described embodiment, the following effects can be obtained. (1) When switching from electric driving to hybrid driving, the electronic control unit 30 controls the throttle opening TA at the completion of the connection of the system clutch 15 to be larger when the atmospheric pressure PA is low than when the atmospheric pressure PA is high. Therefore, it becomes difficult for the intake air amount of the engine 11 when commanding an increase in the engine torque according to the driving request to change due to the level of the atmospheric pressure PA. Therefore, the sluggishness of the acceleration of the hybrid vehicle in a low atmospheric pressure environment can be suppressed.

[0042] (2) The electronic control unit 30 calculates a constant intake air amount opening TACON at which the intake air amount of the engine 11 becomes a predetermined amount based on the atmospheric pressure PA. Then, the electronic control unit 30 controls the throttle opening TA so that the constant intake air amount opening TACON becomes the opening at the completion of the connection of the system clutch 15. Therefore, regardless of the atmospheric pressure PA, the intake air amount of the engine 11 when commanding an increase in the engine torque according to the driving request becomes constant. Therefore, it is easy to keep the acceleration performance of the hybrid vehicle constant regardless of the level of the atmospheric pressure PA.

[0043] (3) The electronic control unit 30 sets the fixed intake throttle opening TACON as the opening at which the following intake air amount is obtained. That is, the exhaust gas amount is an amount that can be purified even by a catalyst in a partially active state, and the intake air amount is such that the torque shock at the time of connecting the system clutch 15 is within an allowable range. Therefore, deterioration of the emissions and drivability of the engine 11 can be suppressed.

[0044] (4) In the present embodiment, when switching from electric driving to the hybrid driving mode, the torque of the power generation motor 12 is controlled as follows. That is, during the period from the restart of the engine 11 until a command to increase the engine torque according to the driving requirement of the hybrid vehicle is given, the torque of the power generation motor 12 is controlled so that the system shaft torque increases at a constant gradient. In order to ensure the acceleration performance of the hybrid vehicle, it is desirable to increase the system shaft torque as much as possible by the start of the increase in the engine torque according to the driving requirement. By controlling the torque of the power generation motor 12 as described above, the increase in the system shaft torque during the above period can be smoothly performed. On the other hand, when the engine torque changes due to the atmospheric pressure PA, it becomes difficult to realize the increase in the system shaft torque. Also, if the increase gradient of the system shaft torque is set within a realizable range even when the atmospheric pressure PA is low, the increase in the system shaft torque becomes slow and the acceleration performance of the hybrid vehicle is restricted. In that regard, in the present embodiment, since the engine torque can be ensured regardless of the level of the atmospheric pressure PA, such problems are less likely to occur.

[0045] The present embodiment can be implemented with the following modifications. The present embodiment and the following modification examples can be implemented in combination with each other within a technically non - conflicting range. · In the above embodiment, the fixed intake throttle opening TACON was set as the opening at which the intake air amount of the engine 11 becomes a certain amount regardless of the level of the atmospheric pressure PA. If the fixed intake throttle opening TACON is set so that when the intake air amount changes slightly due to the atmospheric pressure PA, the opening is larger when the atmospheric pressure PA is low than when the atmospheric pressure PA is high, the jerks during acceleration on high ground can be suppressed.

[0046] ·In the above embodiment, the partial activation of the catalyst and the determination of the completion of activation were determined based on the elapsed time since the restart of the engine 11. These determinations may be made by other methods, for example, based on the catalyst bed temperature.

[0047] ·In the above embodiment, the change in the throttle opening TA from the starting opening to the fixed intake air opening TACON was performed when the catalyst became in a partially activated state. If it is before the completion of the connection of the system clutch 15, the throttle opening TA may be changed from the starting opening to the fixed intake air opening TACON at other times.

Explanation of Signs

[0048] 10…Hybrid system 11…Engine 12…Power generation motor 13…Crankshaft 14…System output shaft 15…System clutch 16…Inverter 17…Battery 20…Transmission 21…Torque converter 22…Transmission mechanism 23…Transmission input shaft 24…Lock-up clutch 30…Electronic control unit 31…Arithmetic processing unit 32…Storage device 33…Air flow meter 34…Atmospheric pressure sensor 35…Intake pressure sensor 36…Crank angle sensor 37…Accelerator pedal sensor 38…Vehicle speed sensor 39…Throttle valve 40…Injector 41…Ignition device

Claims

1. A vehicle control device for controlling a hybrid vehicle having a hybrid system including an engine, a power generation motor, and a catalyst for exhaust purification as a power source, wherein the hybrid system has a clutch interposed between an output shaft of the engine and a rotating shaft of the power generation motor, and is a system having the rotating shaft of the power generation motor as a power take-out shaft, the hybrid vehicle has an electric driving mode in which the engine is stopped and the clutch is disengaged, and a hybrid driving mode in which the clutch is engaged, and when switching from the electric driving mode to the hybrid driving mode, the throttle opening of the engine is set to a partial activation determination value that is set to be shorter than a predicted value of the time required for the clutch connection to be completed from the restart of the engine until the elapsed time from the restart of the engine reaches the partial activation determination value, until it becomes the partial activation determination value, thereafter, the throttle opening is set so that the intake air amount of the engine becomes a constant amount with respect to atmospheric pressure until the elapsed time from the restart of the engine reaches an activation completion determination value that is set to be longer than the predicted value, so that when the clutch connection is completed when switching from the electric driving mode to the hybrid driving mode, the throttle opening of the engine is controlled according to the atmospheric pressure so as to be larger when the atmospheric pressure is low than when the atmospheric pressure is high, wherein the constant amount is determined as the intake air amount when the exhaust amount that can be purified in the state of the catalyst during the period from the partial activation determination value to the activation completion determination value of the elapsed time from the restart of the engine, a vehicle control device.

2. The vehicle control device according to claim 1, wherein when switching from the electric driving mode to the hybrid driving mode, the torque of the power generation motor is controlled so that the torque output by the hybrid system increases at a constant gradient during a period from the restart of the engine until a command to increase the torque of the engine corresponding to the driving request of the hybrid vehicle is issued.

Images