Vehicle control device

Abstract

To suppress torque variation when switching electrical travelling to hybrid travelling.SOLUTION: In restarting an engine 11 accompanying switching from electric travelling to hybrid travelling, an electronic control unit 30, when connection of a system clutch 15 is completed before a start-up period ends, halts stationary ignition control immediately and starts calculation ignition control. The stationary ignition control is control by which an ignition timing of the engine 11 is set to a start-up ignition timing that is an ignition timing for starting the engine. The calculation ignition control is control by which a calculation ignition timing calculated in accordance with a required value of engine torque is set as the ignition timing.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] As shown in Patent Document 1, there is known a hybrid vehicle equipped with a hybrid system that includes an engine, a generator motor, and a clutch interposed therebetween, with the rotating shaft of the generator motor serving as a power takeoff shaft. Such a hybrid vehicle switches between electric driving, in which the vehicle runs with the clutch disengaged and the engine stopped, and hybrid driving, in which the vehicle runs with the clutch engaged and the engine running, depending on the driving conditions. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-152337 Summary of the Invention [Problem to be solved by the invention]

[0004] When switching from electric to hybrid driving, the engine can be restarted using the push start method described below. In a push start, the clutch is first put into a slip state, which transmits part of the torque of the generator motor to the engine. This allows the engine to be restarted at a high engine speed.

[0005] In push-start, the engine may be restarted immediately before or after the clutch is fully engaged and the engine and generator motor are synchronously rotating. In such cases, engine torque is added to the drive torque output by the hybrid system, which can cause a torque step and degrade drivability. [Means for solving the problem]

[0006] A vehicle control device that solves the above problem is applied to a hybrid vehicle that includes a hybrid system having an engine, a generator-motor, and a clutch interposed between the engine and the generator-motor, with the generator-motor's rotating shaft serving as a power takeoff shaft, and that performs electric driving with the engine stopped and the clutch disengaged, and hybrid driving with the engine running and the clutch engaged. The vehicle control device also implements fixed ignition control during the engine startup period, which sets the engine ignition timing to the start-up ignition timing, and calculates ignition control after the startup period ends, which sets the ignition timing to a calculated ignition timing calculated based on the required engine torque. When restarting the engine following a switch from electric driving to hybrid driving, if the clutch is fully engaged before the startup period ends, the vehicle control device interrupts fixed ignition control and starts calculated ignition control.

[0007] If the engine produces too much torque when the clutch is engaged, torque fluctuations may occur, resulting in a deterioration in drivability. On the other hand, calculated ignition control, which calculates ignition timing based on the required engine torque, allows for engine torque adjustment according to the demand. In the vehicle control device described above, when the clutch is fully engaged during fixed ignition control, the calculated ignition control can adjust the engine torque, thereby suppressing torque fluctuations when switching from electric driving to hybrid driving.

[0008] The vehicle control device is preferably configured to implement gradual change control that gradually changes the ignition timing from the start ignition timing to the calculated ignition timing when transitioning from fixed ignition control to calculated ignition control, thereby suppressing a sudden change in engine torque that accompanies the transition from fixed ignition control to calculated ignition timing.

[0009] Furthermore, when implementing the gradual change control, the vehicle control device may be configured to gradually change the ignition timing by the gradual change control only when the ignition timing is advanced, so that the engine torque can be reduced by retarding the ignition timing immediately after the fixed ignition control ends.

[0010] In some situations, ignition by the fixed ignition control is not performed and the fixed ignition control is interrupted when the clutch is fully engaged. In such cases, a step in engine torque does not occur when transitioning from the fixed ignition control to the calculated ignition control. Therefore, it is desirable that the vehicle control device be configured to start the calculated ignition control without performing the gradual-change control when ignition by the fixed ignition control is not performed and the fixed ignition control is interrupted when the clutch is fully engaged.

[0011] When switching from electric driving to hybrid driving, torque substitution control may be performed after clutch engagement is complete. This control gradually increases engine torque and reduces the generator-motor torque by the amount of the increase in engine torque. If gradual change control is performed during torque substitution control, the increase in engine torque may be delayed, which may lengthen the time required to complete the torque substitution control. Therefore, in the case of performing both gradual change control and torque substitution control, if torque substitution control is started during gradual change control, it is desirable for the vehicle control device to increase the gradual change rate of the ignition timing by the gradual change control compared to before the start of the torque substitution control. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a diagram schematically illustrating a configuration of a drive system of a hybrid vehicle equipped with an embodiment of a vehicle control device. [Figure 2] 2 is a diagram schematically illustrating a configuration of a vehicle control device according to the embodiment. FIG. [Figure 3] 3 is a flowchart of the push start ignition timing control executed by the vehicle control device. [Figure 4]4 is a flowchart of a gradual change process performed by the vehicle control device in the push start ignition timing control. [Figure 5] FIG. 10 is a time chart showing, at the time of restarting the engine when the engagement of the system clutch is completed after the fixed ignition control ends, (a) the transition of the engine operation request, (b) the transition of the implementation status of the engine fuel injection, (c) the transition of the engagement state of the system clutch, (d) the transition of the implementation status of the torque switching control, (e) the transition of the number of ignitions after the engine starts, and (f) the transition of the value of the command ignition timing. [Figure 6] FIG. 10 is a time chart showing, at the time of restarting the engine when the system clutch is fully engaged before the fixed ignition control ends, (a) the transition of the engine operation request, (b) the transition of the implementation status of the engine fuel injection, (c) the transition of the engagement state of the system clutch, (d) the transition of the implementation status of the torque switching control, (e) the transition of the number of ignitions after the engine is started, and (f) the transition of the command ignition timing value. [Figure 7] FIG. 10 is a time chart showing, at the time of restarting the engine when the system clutch has completed engagement before the start of fuel injection, (a) the transition of the engine operation request, (b) the transition of the engine fuel injection implementation status, (c) the transition of the engagement state of the system clutch, (d) the transition of the implementation status of torque switching control, (e) the transition of the number of ignitions after engine start, and (f) the transition of the command ignition timing value. DETAILED DESCRIPTION OF THE INVENTION

[0013] An embodiment of a vehicle control device will be described in detail below with reference to FIGS. <Hybrid vehicle drivetrain configuration> First, with reference to FIG. 1, the configuration of the drive system of a hybrid vehicle equipped with a vehicle control device of this embodiment will be described.

[0014] <Hybrid vehicle drivetrain configuration> First, with reference to FIG. 1 , the configuration of a drive system of a hybrid vehicle controlled by a vehicle control device of this embodiment will be described. The hybrid vehicle has a hybrid system 10 as a power source. The hybrid system 10 has an engine 11, a generator motor 12, and a system clutch 15. The hybrid system 10 has a rotating shaft of the generator motor 12 as a power output shaft of the hybrid system 10. The system clutch 15 is interposed between a crankshaft 13, which is the output shaft of the engine 11, and a system output shaft 14. The system clutch 15 connects and disconnects the crankshaft 13 and the system output shaft 14. The hybrid system 10 also has an inverter 16 and a battery 17. The inverter 16 controls the amount of electric power exchanged between the generator motor 12 and the battery 17.

[0015] The hybrid vehicle is also provided with a transmission 20. 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 a 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 speed of rotation of the transmission input shaft 23 and transmits it to the wheels of the hybrid vehicle. Furthermore, 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 going through the torque converter 21.

[0016] <Configuration of vehicle control device> Next, the configuration of the vehicle control device of this embodiment will be described with reference to Fig. 2. The vehicle control device includes an electronic control unit 30. The electronic control unit 30 includes an arithmetic processing device 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 various parts of the hybrid vehicle. These 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 detects the intake air flow rate GA of the engine 11. The atmospheric pressure sensor 34 detects the atmospheric pressure PA. The intake pressure sensor 35 detects the intake pressure PM of the engine 11. The crank angle sensor 36 detects the crank angle CRNK, which is the rotational phase of the crankshaft 13 of the engine 11. The accelerator pedal sensor 37 detects the accelerator pedal depression amount ACC by the driver of the hybrid vehicle. The vehicle speed sensor 38 detects the vehicle speed V of the hybrid vehicle. The electronic control unit 30 calculates the engine speed NE, which is the rotational speed of the crankshaft 13 of the engine 11, from the detection result of the crank angle sensor 36.

[0018] The electronic control unit 30 controls the hybrid system 10 based on the detection results of these 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 a throttle valve 39, an injector 40, and an ignition device 41. The electronic control unit 30 also controls the torque of the generator motor 12 through control of the inverter 16. Furthermore, the electronic control unit 30 controls the system clutch 15. In the following description, the opening of the throttle valve 39 will be referred to as a throttle opening TA.

[0019] <Driving control of hybrid vehicles> The electronic control unit 30 switches between electric driving and hybrid driving depending on the driving conditions of the hybrid vehicle. In the following description, hybrid driving will be referred to as HV driving. During electric driving, the electronic control unit 30 stops the engine 11 and disengages the system clutch 15. During HV driving, the electronic control unit 30 operates the engine 11 and engages the system clutch 15.

[0020] While the hybrid vehicle is traveling, the electronic control unit 30 calculates the required drive torque based on the accelerator pedal depression amount ACC, the vehicle speed V, etc. The required drive torque represents the required value of the system shaft torque required for traveling of the hybrid vehicle. The system shaft torque represents the torque transmitted to the transmission 20 by the system output shaft 14 of the hybrid system 10. During electric travel, the electronic control unit 30 controls the inverter 16 to supply the generator motor 12 with the electric power required to generate the required drive torque from the battery 17. On the other hand, during HV travel, the electronic control unit 30 calculates the battery required torque based on the charge amount of the battery 17. The electronic control unit 30 controls the charge / discharge amount of the battery 17 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 by the generator motor 12 in order to control the charge / discharge amount. Next, the electronic control unit 30 calculates the difference between the required drive torque and the battery required torque as the required engine torque TE*, which is the required value of engine torque.The electronic control unit 30 then controls the engine 11 so as to obtain the intake amount necessary to generate engine torque equal to the required engine torque TE*.The electronic control unit 30 also controls the inverter 16 so that the generator motor 12 generates torque equivalent to the battery required torque.

[0021] When switching from electric driving to HV driving, the electronic control unit 30 restarts the engine 11 and engages the system clutch 15. If the engine 11 is self-startable and a switch from electric driving to HV driving is requested, the electronic control unit 30 first restarts the engine 11 and then engages the system clutch 15. On the other hand, if the engine 11 is not self-startable and a switch from electric driving to HV driving is requested, the electronic control unit 30 restarts the engine 11 by a push start using the power of the generator motor 12. During a push start, the electronic control unit 30 places the system clutch 15 in a slip state and restarts the engine 11 while rotating it with the power of the generator motor 12. The slip state is a state in which torque is transmitted between the engine 11 and the generator motor 12 while allowing differential rotation between the crankshaft 13 and the system output shaft 14.

[0022] After the engine 11 is restarted, the electronic control unit 30 sets the value of the required engine torque TE* to "0" until the engagement of the system clutch 15 is completed, thereby maintaining a state in which the engine 11 does not generate any shaft torque. The state in which the engagement of the system clutch 15 is completed is a state in which the rotation speed of the crankshaft 13 and the rotation speed of the system output shaft 14 are equal, i.e., a state in which the engine 11 and the generator motor 12 rotate synchronously. In the following description, the rotation speed of the system output shaft 14, i.e., the rotation speed of the generator motor 12, is referred to as the MG rotation speed NM.

[0023] Furthermore, after the system clutch 15 is fully engaged, the electronic control unit 30 executes torque switching control to gradually increase the engine torque from "0" while reducing the torque of the generator motor 12 by the amount of the increase in engine torque.

[0024] <Ignition timing control during push start> Next, the ignition timing control of the engine 11 during push start will be described. During push start, the electronic control unit 30 controls the ignition timing by selecting one of three control methods: fixed ignition control, calculated ignition control, and gradual change control. Fixed ignition control is a control that sets the command ignition timing AOP, which is the command value for the ignition timing, to the starting ignition timing AOPS, which is the ignition timing suitable for starting the engine 11. Calculated ignition control is a control that sets the ignition timing to a timing that will obtain an engine torque equal to the requested engine torque TE*, based on the requested engine torque TE*, engine speed NE, and engine load factor KL. Gradual change control is a control that gradually changes the ignition timing when transitioning from fixed ignition control to calculated ignition control.

[0025] During a push start, the engine speed NE and the intake air volume of the engine 11 change each time. The ignition timing suitable for starting also changes depending on the engine speed NE and intake air volume at start. When a push start is performed while driving on a low-μ road, the MG speed NM may suddenly increase after starting. On the other hand, as the MG speed NM increases, the increase in the engine speed NE required for the engine 11 to be able to rotate synchronously with the generator motor 12 after start and for the system clutch 15 to be fully engaged increases. Therefore, if the MG speed NM suddenly increases after starting the engine 11, if the increase in the engine speed NE is delayed, the MG speed NM will increase during that time, significantly delaying the full engagement of the system clutch 15. This results in a sluggish acceleration of the hybrid vehicle.

[0026] In contrast, the electronic control unit 30 calculates the value of the start ignition timing AOPS during a push start based on the MG rotation speed NM, the engine rotation speed NE, and the intake pressure PM of the engine 11. Specifically, when the difference between the MG rotation speed NM and the engine rotation speed NE is not large, the electronic control unit 30 calculates the value of the start ignition timing AOPS to be the ignition timing that improves the startability of the engine 11 for the engine rotation speed NE and the intake pressure PM. When the difference between the MG rotation speed NM and the engine rotation speed NE is large, the electronic control unit 30 calculates the value of the start ignition timing AOPS to be the ignition timing that increases engine torque compared to the above case. Thus, the fixed ignition control here does not necessarily mean control in which the command ignition timing AOP is uniformly fixed. Fixed ignition control differs from calculated ignition control in the following respects. That is, in the calculated ignition control, the ignition timing is controlled so as to obtain an engine torque equal to the required engine torque TE*, whereas in the fixed ignition control, the ignition timing is controlled regardless of the required engine torque TE*.

[0027] Figure 3 shows a flowchart of push start ignition timing control, which is control for setting the value of command ignition timing AOP during push start. When switching from electric driving to EV driving, the electronic control unit 30 repeatedly executes the process shown in the figure at predetermined control intervals from when a restart of the engine 11 is requested until torque switching control is completed. When restarting the engine 11, the electronic control unit 30 starts ignition timing control using fixed ignition control. In other words, when the process of Figure 3 is executed for the first time after a restart request, the ignition timing control is set to fixed ignition control.

[0028] 3 starts, the electronic control unit 30 first determines in step S100 whether or not fixed ignition control was performed in the previous control cycle. If the electronic control unit 30 has performed fixed ignition control (S100: YES), the electronic control unit 30 proceeds to step S110. If the electronic control unit 30 has not performed fixed ignition control (S100: NO), that is, if the electronic control unit 30 has performed gradual-change control or calculated ignition control in the previous control cycle, the electronic control unit 30 proceeds to step S160.

[0029] In step S110, the electronic control unit 30 determines whether the number of ignitions after start is equal to or greater than a predetermined number X. The number of ignitions after start is the number of ignitions performed by the engine 11 after restart. If the number of ignitions after restart is equal to or greater than the predetermined number X (S110: YES), the electronic control unit 30 proceeds to step S150, and if the number of ignitions after restart is less than the predetermined number X (S120: NO), the electronic control unit 30 proceeds to step S120.

[0030] In step S120, the electronic control unit 30 determines whether or not engagement of the system clutch 15 is complete. If engagement of the system clutch 15 is complete (S120: YES), the electronic control unit 30 proceeds to step S130, and if engagement of the system clutch 15 is not complete (S120: NO), the electronic control unit 30 proceeds to step S180.

[0031] In step S130, the electronic control unit 30 determines whether the number of ignitions after starting is 0. If the number of ignitions after starting is 0 (S130: YES), the electronic control unit 30 proceeds to step S140, and if the number of ignitions after starting is not 0 (S130: NO), the electronic control unit 30 proceeds to step S150.

[0032] In step S140, the electronic control unit 30 records that the ignition timing control has been shifted from fixed ignition control to calculated ignition control, and then proceeds to step S160. On the other hand, in step S150, the electronic control unit 30 records that the ignition timing control has been shifted from fixed ignition control to gradual-change control, and then proceeds to step S160.

[0033] In step S160, the electronic control unit 30 calculates the calculated ignition timing SARQ based on the required engine torque TE*, engine speed NE, and engine load factor KL, and then proceeds to step S170. The engine load factor KL represents the intake air filling rate of the cylinders of the engine 11. The electronic control unit 30 calculates, as the value of the calculated ignition timing SARQ, the ignition timing that will provide an engine torque equal to the value of the required engine torque TE* at the current engine speed NE and engine load factor KL.

[0034] In step S170, the electronic control unit 30 determines whether or not the calculation ignition control is in progress. The electronic control unit 30 also determines that the calculation control is in progress if the process proceeds to step S170 in the same control period as the control period in which the transition from fixed ignition control to calculation ignition control was recorded in the previous step S140. If the electronic control unit 30 determines that the calculation ignition control is in progress (S170: YES), the electronic control unit 30 proceeds to step S190. On the other hand, if the electronic control unit 30 determines that the calculation ignition control is not in progress (S170: NO), that is, if the gradual change control is in progress, the electronic control unit 30 performs the gradual change control process shown in FIG.

[0035] In step S180, the electronic control unit 30 sets the ignition timing at start AOPS as the value of the commanded ignition timing AOP. In this embodiment, fixed ignition control is performed by setting the ignition timing at start AOPS as the value of the commanded ignition timing AOP in step S180. After processing step S180, the electronic control unit 30 ends the processing for setting the commanded ignition timing AOP for the current control cycle.

[0036] In step S190, the electronic control unit 30 sets the calculated ignition timing SARQ calculated in the previous step S160 as the value of the commanded ignition timing AOP. In this embodiment, in step S190, the calculated ignition timing SARQ is set as the value of the commanded ignition timing AOP, thereby performing calculated ignition control. After processing step S190, the electronic control unit 30 ends the processing for setting the commanded ignition timing AOP for the current control cycle.

[0037] 4 shows a flowchart of the process for gradual change control that is performed by the electronic control unit 30. The process in this figure is performed when calculation ignition control is not being performed in step S170 of FIG.

[0038] When the gradual change control process starts, the electronic control unit 30 first determines in step S200 whether the above-mentioned torque substitution solution control is being performed. If the torque substitution control is not being performed (S200: NO), the electronic control unit 30 sets a predetermined positive value S1 as the value of the gradual change amount SM in step S210, and then proceeds to step S230. On the other hand, if the torque substitution control is being performed (S200: YES), the electronic control unit 30 sets a predetermined value S2, which is larger than the value S1, as the value of the gradual change amount SM in step S220, and then proceeds to step S230.

[0039] In step S230, the electronic control unit 30 calculates the value of the gradual ignition timing AOPSM by adding the gradual change amount SM to the previous value of the commanded ignition timing AOP. The previous value of the commanded ignition timing AOP is the value of the commanded ignition timing AOP set in the previous control cycle. Next, in step S240, the electronic control unit 30 determines whether the calculated value of the gradual ignition timing AOPSM is equal to or greater than the value of the calculated ignition timing SARQ. If the value of the gradual ignition timing AOPSM is less than the value of the calculated ignition timing SARQ (S240: NO), the electronic control unit 30 sets the value of the gradual ignition timing AOPSM as the value of the commanded ignition timing AOP in step S250. Next, the electronic control unit 30 ends the process for setting the commanded ignition timing AOP in the current control cycle. On the other hand, if the value of the gradual ignition timing AOPSM is equal to or greater than the value of the calculated ignition timing SARQ (S240: YES), the electronic control unit 30 sets the value of the calculated ignition timing SARQ as the value of the command ignition timing AOP in step S260. Then, in step S270, the electronic control unit 30 records that it has transitioned to calculated ignition control, and then ends the process for setting the command ignition timing AOP for the current control cycle.

[0040] <Effects of the embodiment> The operation and effects of this embodiment will be described. When switching from electric driving to HV driving, the electronic control unit 30 engages the system clutch 15 and restarts the engine 11. After the restart, the electronic control unit 30 sets the value of the required engine torque TE* to "0" and maintains the shaft torque of the engine 11 at a value close to "0" until the engagement of the system clutch 15 and the restart of the engine 11 are completed. Then, once the engagement of the system clutch 15 and the restart of the engine 11 are completed, the electronic control unit 30 executes torque switching control to increase the engine torque while suppressing fluctuations in the system shaft torque.

[0041] When switching from electric driving to HV driving, the electronic control unit 30 may restart the engine 11 by a push start using the power of the generator motor 12. When a push start is performed, the electronic control unit 30 starts to engage the system clutch 15 prior to restarting the engine 11. Then, the electronic control unit 30 restarts the engine 11 while rotating the crankshaft 13 with the torque of the generator motor 12 transmitted through the system clutch 15, which is now in a slipping state.

[0042] When a restart of the engine 11 is requested by push start, the electronic control unit 30 starts ignition timing control using fixed ignition control. Note that when a restart is requested, fuel injection into the engine 11 may not have started. Even in this case, the electronic control unit 30 sets the command ignition timing AOP, but does not actually ignite the air-fuel mixture based on that setting until fuel injection starts.

[0043] In the push start ignition timing control, the electronic control unit 30 ends the fixed ignition control when, after a restart request, the number of post-start ignitions reaches a predetermined number X, or when the engagement of the system clutch 15 is completed. After ending the fixed ignition control, the electronic control unit 30 transitions to calculated ignition control via gradual change control. If the number of post-start ignitions is "0" when the engagement of the system clutch 15 is completed, the fixed ignition control ends without actually igniting the air-fuel mixture through the fixed ignition control. In this case, the electronic control unit 30 transitions directly from the fixed ignition control to the calculated ignition control without performing gradual change control.

[0044] Furthermore, during the gradual change control, the electronic control unit 30 updates the commanded ignition timing AOP based on the previous value of the commanded ignition timing AOP and the calculated ignition timing SARQ in the following manner. That is, during the gradual change control, if the calculated ignition timing SARQ is earlier than the previous value of the commanded ignition timing AOP, the electronic control unit 30 advances the commanded ignition timing AOP from the previous value by the value of the gradual change amount SM. On the other hand, if the calculated ignition timing SARQ is the same as or later than the previous value of the commanded ignition timing AOP, the gradual change control ends at that point and transitions to the calculated ignition control. That is, the electronic control unit 30 gradually changes the commanded ignition timing AOP only when the commanded ignition timing AOP advances when transitioning from fixed ignition control to calculated ignition control. Note that, when torque substitution control is initiated during the gradual change control, the electronic control unit 30 increases the gradual change rate of the commanded ignition timing AOP compared to before the torque substitution control was initiated.

[0045] Figure 5 shows an example of the control mode of the electronic control unit 30 when the engagement of the system clutch 15 is completed after the fixed ignition control ends when the engine 11 is restarted by push start. Figure 5(a) shows the transition of the operation request of the engine 11, Figure 5(b) shows the transition of the implementation status of the fuel injection of the engine 11, and Figure 5(c) shows the transition of the engagement state of the system clutch 15. Figure 5(d) shows the transition of the implementation status of the torque switching control, Figure 5(e) shows the transition of the number of ignitions after the start of the engine 11, and Figure 5(f) shows the transition of the value of the command ignition timing AOP.

[0046] 5(a) indicates that the electronic control unit 30 is requesting the engine 11 to be stopped when the request is off, and that the electronic control unit 30 is requesting the engine 11 to be stopped when the request is on. Therefore, in the case of FIG. 5, the electronic control unit 30 requests the engine 11 to be restarted at time t0 when the request for the engine 11 to be stopped switches from off to on.

[0047] Furthermore, the values ​​of the ignition timing at start AOPS and the calculated ignition timing SARQ used to set the commanded ignition timing AOP vary depending on the operating conditions of the engine 11, such as the engine speed NE. For ease of explanation, Fig. 5(f) and Fig. 6(f) and Fig. 7(f) (to be described later) show the transition of the value of the commanded ignition timing AOP when the ignition timing at start AOPS and the calculated ignition timing SARQ are each maintained at a constant value during the period in the figure.

[0048] The electronic control unit 30 starts ignition timing control using fixed ignition control at time t0 when a restart of the engine 11 is requested. Then, the electronic control unit 30 starts fuel injection into the engine 11 at a subsequent time t1. That is, ignition using fixed ignition control starts from time t1. The electronic control unit 30 also starts counting the number of ignitions after start from time t1. In the case of FIG. 5, the number of ignitions after start reaches the predetermined number X at time t2, which is before time t3 when engagement of the system clutch 15 is completed, and the start period ends. At this time, the electronic control unit 30 ends the fixed ignition control and starts gradual-change control at time t2 when the start period ends.

[0049] FIG. 5(f) shows the transition of the commanded ignition timing AOP when the calculated ignition timing SARQ at time t2 is earlier than the starting ignition timing AOPS (solid line). In this case, the electronic control unit 30 gradually advances the commanded ignition timing AOP from the starting ignition timing AOPS to the calculated ignition timing SARQ. Then, when the commanded ignition timing AOP reaches the calculated ignition timing SARQ at time t4, the electronic control unit 30 ends the gradual change control and starts the calculated ignition control. Note that in FIG. 5, torque substitution control begins at time t5, which is after time t4. If the engine were to switch directly from fixed ignition control to calculated ignition control without performing such gradual change control, the ignition timing would be suddenly advanced, causing a sudden increase in engine torque. At this time, if the engine torque were to be transmitted to the system output shaft 14, a torque shock may occur. Therefore, the electronic control unit 30 gradually advances the commanded ignition timing AOP using gradual change control to prevent the occurrence of a torque shock.

[0050] If the engine 11 generates torque when the system clutch 15 is fully engaged, the engine torque may be added to the system shaft torque, resulting in a torque step. Therefore, the electronic control unit 30 sets the value of the required engine torque TE* to "0" until the torque substitution control is started. When the required engine torque TE* is "0," a value that sets the engine torque to "0" is set as the value of the calculated ignition timing SARQ. As a result, at time t2 when the fixed ignition control is ended, the calculated ignition timing SARQ may be set to a timing later than the starting ignition timing AOPS.

[0051] In FIG. 5(f), the dashed line shows the transition of the commanded ignition timing AOP when the calculated ignition timing SARQ at time t2 is earlier than the starting ignition timing AOPS. In this case, the electronic control unit 30 does not actually perform gradual change control, but instead sets the commanded ignition timing AOP to the value of the commanded ignition timing AOP from time t2. That is, when transitioning from fixed ignition control to calculated ignition control, the electronic control unit 30 performs gradual change control only when the value of the commanded ignition timing AOP is changed to increase engine torque. Therefore, when a reduction in engine torque is required, the engine torque can be reduced as the fixed ignition control ends. This prevents a torque step from occurring when the system clutch 15 is engaged.

[0052] Fig. 6 shows an example of the control mode of the electronic control unit 30 when fixed ignition control ends after complete engagement of the system clutch 15 during restart of the engine 11 by push start. Fig. 6(a) shows the transition of the operation request for the engine 11, Fig. 6(b) shows the transition of the implementation status of fuel injection for the engine 11, and Fig. 6(c) shows the transition of the engagement state of the system clutch 15. Fig. 6(d) shows the transition of the implementation status of torque switching control, Fig. 6(e) shows the transition of the number of ignitions after start of the engine 11, and Fig. 6(f) shows the transition of the value of the command ignition timing AOP.

[0053] In the case of Fig. 6, a request to restart the engine 11 is made at time t10, and fuel injection into the engine 11 is started at a subsequent time t11. Then, in the case of Fig. 6, engagement of the system clutch 15 is completed at a subsequent time t12, and at a further subsequent time t13, the number of ignitions after start reaches the predetermined number X, and the start period ends. In this case, the electronic control unit 30 ends the fixed ignition control and starts the gradual change control at the time t12 when engagement of the system clutch 15 is completed.

[0054] As described above, the electronic control unit 30 completes the transition from electric driving to HV driving by performing torque substitution control after the system clutch 15 is fully engaged. If gradual change control continues after the torque substitution control begins, the increase in engine torque will be delayed, which will delay the end of the torque substitution control and ultimately the transition to HV driving. In the example shown in FIG. 6, the torque substitution control begins at time t13, which is earlier than time t14, when the gradual change control ends. The electronic control unit 30 sets the gradual change rate of the commanded ignition timing AOP during the gradual change control from time t13 onward to be higher than during the period before time t13. This allows the electronic control unit 30 to reduce the delay in the increase in engine torque during the torque substitution control due to the gradual change control.

[0055] Fig. 7 shows an example of the control mode of the electronic control unit 30 when the engagement of the system clutch 15 is completed before the start of fuel injection during restart of the engine 11 by push start. Fig. 7(a) shows the transition of the operation request of the engine 11, Fig. 7(b) shows the transition of the implementation status of fuel injection of the engine 11, and Fig. 7(c) shows the transition of the engagement state of the system clutch 15. Fig. 7(d) shows the transition of the implementation status of the torque switching control, Fig. 7(e) shows the transition of the number of ignitions after start of the engine 11, and Fig. 7(f) shows the transition of the value of the command ignition timing AOP.

[0056] In the example shown in FIG. 7, a restart of the engine 11 is requested at time t20, and the system clutch 15 is engaged at a subsequent time t21. Then, fuel injection of the engine 11 is initiated at a subsequent time t22. The electronic control unit 30 starts calculating the commanded ignition timing AOP using the fixed ignition control at time t20, when the restart of the engine 11 is requested. The electronic control unit 30 ends the fixed ignition control at time t21, when the system clutch 15 is engaged. However, in this case, fuel injection of the engine 11 is not initiated until time t22. Therefore, the fixed ignition control ends without actually igniting fuel based on the calculated commanded ignition timing AOP. Therefore, even if the value of the commanded ignition timing AOP changes stepwise from the starting ignition timing AOPS to the calculated ignition timing SARQ, no step in engine torque occurs because the engine 11 has not yet started at that time. Therefore, the electronic control unit 30 at this time starts the calculated ignition control without performing the gradual change control at time t21 when the engagement of the system clutch 15 is completed. In Fig. 7, the torque switching control is started at time t23 after the calculated ignition control is started.

[0057] According to the vehicle control device of the present embodiment described above, the following effects can be achieved. (1) If engine torque is excessive when the system clutch 15 is engaged, torque fluctuations may occur, resulting in poor drivability. In fixed ignition control, the commanded ignition timing AOP is set to an ignition timing suitable for starting the engine 11. Because fixed ignition control does not allow for accurate adjustment of engine torque, torque fluctuations may be unavoidable if the system clutch 15 is engaged while in fixed ignition control. In contrast, calculated ignition control calculates the commanded ignition timing AOP to generate engine torque equal to the requested engine torque TE*. Therefore, if calculated ignition control is performed when the system clutch 15 is fully engaged, engine torque can be controlled to prevent torque fluctuations. When restarting the engine 11 due to a switch from electric driving to hybrid driving, if the system clutch 15 is fully engaged before the end of the starting period, the electronic control unit 30 interrupts fixed ignition control and switches to calculated ignition control. This suppresses torque fluctuations associated with the engagement of the system clutch 15.

[0058] (2) When transitioning from fixed ignition control to calculated ignition control, the electronic control unit 30 gradually changes the command ignition timing AOP from the starting ignition timing AOPS to the calculated ignition timing SARQ, thereby suppressing a sudden change in engine torque that accompanies the transition from fixed ignition control to calculated ignition control.

[0059] (3) In the gradual change control, the electronic control unit 30 gradually changes the commanded ignition timing AOP only when the commanded ignition timing AOP changes to the advance side. In other words, even in the gradual change control, the electronic control unit 30 immediately changes the commanded ignition timing AOP without gradually changing it to the retard side. In this case, if a decrease in engine torque is required, the engine torque can be decreased immediately upon termination of the fixed ignition control.

[0060] (4) If ignition by the fixed ignition control is not performed and the fixed ignition control is interrupted due to the completion of engagement of the system clutch 15, no step occurs in the engine torque even if gradual change control is not performed. In such a case, the electronic control unit 30 starts the calculated ignition control without performing the gradual change control. Therefore, adjustment of the engine torque by the calculated ignition control can be started early.

[0061] (5) When torque substitution control is initiated during gradual change control, the electronic control unit 30 increases the rate of gradual change of the commanded ignition timing AOP by the gradual change control compared to before the torque substitution control was initiated. This reduces the delay in the increase in engine torque during torque substitution control due to the gradual change control. As a result, the end of torque substitution control, and ultimately the completion of the transition to HV driving, is less likely to be delayed.

[0062] <Other embodiments> This embodiment can be modified as follows: This embodiment and the following modifications can be combined and implemented within the scope of technical compatibility.

[0063] In the above embodiment, the gradual change rate of the command ignition timing AOP in the gradual change control is changed before and after the start of the torque substitution control. However, it is also possible not to change the gradual change rate in accordance with the torque substitution control.

[0064] In the above embodiment, if ignition by fixed ignition control is not performed and engagement of the system clutch 15 is completed, calculated ignition control is started without performing gradual change control, but gradual change control may also be performed in such a case.

[0065] In the above embodiment, the gradual change control gradually changes the commanded ignition timing AOP only in response to a change to the advance side, but the gradual change may also be performed in response to a change to the retard side.

[0066] Regardless of the situation, the fixed ignition control may always be directly switched to the calculated ignition control. In the above embodiment, the start period ends when the number of post-start ignitions, which is the number of ignitions after the start of the engine 11, reaches a predetermined number X. If the engagement of the system clutch 15 is not completed before the end of the start period, the fixed ignition control is continued until the end of the start period. The end of the start period may be determined based on a parameter other than the number of post-start ignitions. For example, the start period of the engine 11 may be determined based on the number of consecutive complete combustions of the engine 11 after the start of the engine, the elapsed time, the increase in the engine speed NE, etc. [Explanation of symbols]

[0067] 10...Hybrid system 11...Engine 12...Generator motor 13...Crankshaft 14...System output shaft 15...System clutch 16...Inverter 17...Battery 20...Gearbox 21...Torque converter 22...Transmission mechanism 23...Transmission input shaft 24...Lock-up clutch 30...Electronic control unit 31...Processing device 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. The present invention is applied to a hybrid vehicle that includes a hybrid system having an engine, a generator motor, and a clutch interposed between the engine and the generator motor, with a rotating shaft of the generator motor as a power takeoff shaft, and that performs electric running in which the engine is stopped and the clutch is disengaged, and hybrid running in which the engine is operated and the clutch is engaged, A vehicle control device that performs fixed ignition control for setting an ignition timing of the engine to an ignition timing at a start time during a start period of the engine, and performs calculated ignition control for setting the ignition timing to a calculated ignition timing calculated according to a required value of engine torque after the start period ends, When the engine is restarted in response to the switch from the electric traveling to the hybrid traveling, if the engagement of the clutch is completed before the end of the starting period, the fixed ignition control is interrupted at that point and the control is switched to the calculated ignition control, When transitioning from the fixed ignition control to the calculated ignition control, a gradual change control is performed to gradually change the ignition timing from the starting ignition timing to the calculated ignition timing, The gradual change of the ignition timing by the gradual change control is performed only when the ignition timing changes to the advance side, If ignition is not performed by the fixed ignition control and the fixed ignition control is interrupted due to completion of engagement of the clutch, the calculated ignition control is started without performing the gradual change control. Vehicle control device.

2. The present invention is applied to a hybrid vehicle that includes a hybrid system having an engine, a generator motor, and a clutch interposed between the engine and the generator motor, with a rotating shaft of the generator motor as a power takeoff shaft, and that performs electric running in which the engine is stopped and the clutch is disengaged, and hybrid running in which the engine is operated and the clutch is engaged, A vehicle control device that performs fixed ignition control for setting an ignition timing of the engine to an ignition timing at a start time during a start period of the engine, and performs calculated ignition control for setting the ignition timing to a calculated ignition timing calculated according to a required value of engine torque after the start period ends, When the engine is restarted in response to the switch from the electric traveling to the hybrid traveling, if the engagement of the clutch is completed before the end of the starting period, the fixed ignition control is interrupted at that point and the control is switched to the calculated ignition control, When transitioning from the fixed ignition control to the calculated ignition control, a gradual change control is performed to gradually change the ignition timing from the starting ignition timing to the calculated ignition timing, The gradual change of the ignition timing by the gradual change control is performed only when the ignition timing changes to the advance side, a torque switching control is performed after the clutch is fully engaged, in which the torque of the engine is gradually increased and the torque of the generator motor is reduced by the increase in the torque of the engine; When the torque substitution control is started during the gradual change control, the gradual change speed of the ignition timing by the gradual change control is set to be higher than that before the torque substitution control is started. Vehicle control device.

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