Vehicle control device

Abstract

To provide a vehicle controller capable of improving engine start responsiveness while suppressing start shock occurring as an engine is started.SOLUTION: A vehicle controller executes the following: (a) when selecting the method of the start control of an engine, predicting whether start shock occurring when it is assumed that an early ignition start method has been executed as the start control of the engine, is within a prescribed acceptable range on the basis of the values of the rotational speed of a rotary electric machine, system shaft torque input to a torque converter, and the turbine rotational speed of the torque converter at a time point when selecting the method of the start control of the engine; (b) when predicting that the start shock is within the prescribed acceptable range, selecting the early ignition start method as the start control of the engine; and (c) when predicting that the start shock is outside the prescribed acceptable range, selecting a push start method as the start control of the engine.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a control device for a vehicle that includes an engine, a rotating electric machine connected to the engine via a clutch, and a torque converter connected to the rotating electric machine. [Background technology]

[0002] There is known a control device for a vehicle that includes an engine and a rotating electric machine as a driving force source for driving the vehicle, a clutch that connects and disconnects a power transmission path between the engine and the rotating electric machine, and a torque converter that transmits the power of the driving force source for driving the vehicle to driving wheels. For example, there is a vehicle control device described in Patent Document 1. Patent Document 1 discloses an early ignition start method as a method of engine start control, in which the clutch is engaged and cranked by the rotating electric machine, fuel is injected and ignited into the engine before the clutch is synchronized, and the clutch is released once the combustion can be continued, and then the clutch is re-engaged. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2014 / 97376 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when a vehicle using a rotating electric machine as a driving force source is traveling, for example, if the engine is started by the early ignition start method when the rotation speed of the rotating electric machine is low, the engine rotation speed is changed to the synchronous rotation speed of the clutch before the clutch is released, and the inertia of the engine is transmitted to the rotor shaft of the rotating electric machine via the clutch, which may cause a start shock that exceeds the allowable range. Therefore, when there is a possibility of such a start shock occurring, it is preferable to start the engine by the push start method. The push start method is an engine start control method in which the clutch is engaged to increase the engine rotation speed by the rotating electric machine, and after the clutch is synchronized, fuel is injected into the engine and ignited to start the engine. However, while the push start method reduces the start shock compared to the early ignition start method, it has inferior start response.

[0005] The present invention has been made against the background of the above circumstances, and its object is to provide a vehicle control device that can improve engine start-up responsiveness while suppressing the start-up shock that occurs with engine start-up. [Means for solving the problem]

[0006] The gist of a first aspect of the present invention is a control device for a vehicle including an engine and a rotating electric machine as a driving force source for driving the vehicle, a clutch that connects and disconnects a power transmission path between the engine and the rotating electric machine, and a torque converter that transmits power of the driving force source for driving the vehicle to driving wheels, the control device comprising: (a) an early ignition start method in which the clutch is engaged and cranked by the rotating electric machine, fuel is injected into the engine before the clutch is synchronized, and when the combustion can be continued, the clutch is temporarily released and then the clutch is engaged again; and a push start method in which the clutch is engaged and the engine rotation speed is increased by the rotating electric machine, and after the clutch is synchronized, fuel is injected into the engine, ignited, and the engine is started; When selecting a method of engine start control, a method of engine start control is selected based on values ​​of the rotation speed of the rotating electric machine, the system shaft torque input to the torque converter, and the turbine rotation speed of the torque converter at the time of selecting the method of engine start control. The aboveA method for controlling the engine starting operation of an engine that is not an early ignition start method is provided, comprising: predicting whether a starting shock occurring when an early ignition start method is executed is within a predetermined tolerance range; (b) selecting the early ignition start method as a starting control for the engine when the starting shock is predicted to be within the predetermined tolerance range; and (c) selecting the early ignition start method as a starting control for the engine when the starting shock is predicted to be outside the predetermined tolerance range. The above To select a push start method. Effect of the Invention

[0007] According to the vehicle control device of the present invention, (a) From early ignition starting method and push start starting method, When the engine start control method is selected, it is predicted whether or not a start shock occurring when an early ignition start method is executed as the engine start control is within a predetermined allowable range based on the values ​​of the rotation speed of the rotating electric machine, the system shaft torque input to the torque converter, and the turbine rotation speed of the torque converter at the time when the engine start control method is selected, and (b) when the start shock is predicted to be within the predetermined allowable range, the early ignition start method is selected as the engine start control, and (c) when the start shock is predicted to be outside the predetermined allowable range, the push start method is selected as the engine start control. When the start shock occurring due to the early ignition start method is predicted to be within the predetermined allowable range, the early ignition start method is selected, and when the start shock is predicted to be outside the predetermined allowable range, the push start method is selected. This makes it possible to improve the response of the engine start while suppressing the start shock occurring with the start of the engine.

[0008] According to the vehicle control device of the second aspect of the invention, in the first aspect of the invention, the prediction of whether the starting shock is within the predetermined allowable range is performed by calculating either the rotation speed of the rotating electric machine or the system shaft torque at the synchronization timing of the clutch as a synchronous vehicle state value on the assumption that the early ignition start method is executed as the engine start control, and then comparing the calculated synchronous vehicle state value with a predetermined judgment value. In this way, the rotation speed of the rotating electric machine and the system shaft torque at the synchronization timing of the clutch are calculated, and the calculated rotation speed of the rotating electric machine and the system shaft torque are compared with a judgment value that is predetermined for predicting whether the starting shock is within the predetermined allowable range. By this comparison, it is predicted whether the starting shock generated by engine start is within the predetermined allowable range, and an engine start control method that achieves both suppression of the starting shock and responsiveness of the engine start is selected according to the prediction.

[0009] According to the vehicle control device of the third aspect of the invention, in the second aspect of the invention, when the synchronized vehicle state value is the system shaft torque at the synchronization timing of the clutch, the judgment value is switched according to a predicted value of the transmission torque capacity of the clutch at the synchronization timing of the clutch. The magnitude of the engine torque transmitted by the clutch as a disturbance changes according to the transmission torque capacity of the clutch at the synchronization timing of the clutch. Therefore, by switching the judgment value for predicting whether or not the starting shock is within a predetermined allowable range according to the transmission torque capacity of the clutch, the accuracy of prediction of whether or not the starting shock is within a predetermined allowable range is improved. [Brief description of the drawings]

[0010] [Figure 1] 1 is a schematic configuration diagram of a vehicle equipped with an electronic control device according to a first embodiment of the present invention, and is also a functional block diagram showing essential parts of control functions for various controls in the vehicle. [Diagram 2] FIG. 4 is a diagram showing an example of an EV / EHV region map used for switching between a motor driving mode and a hybrid driving mode. [Diagram 3] 2 is an example of a time chart assuming that engine start control is executed by the electronic control device shown in FIG. 1 using an early ignition start method. [Figure 4] 4 is a diagram illustrating the relationship between a starting shock that occurs when an engine is started using an early ignition start method and the rotation speed of a rotating electrical machine. FIG. [Diagram 5] 2 is an example of a flowchart illustrating a main part of a control operation of the electronic control device shown in FIG. [Figure 6] 11 is an example of a time chart assuming that engine start control is executed by an electronic control device according to a second embodiment of the present invention using an early ignition start method. [Figure 7] 10 is an example of a flowchart illustrating a main part of a control operation of an electronic control device according to a second embodiment of the present invention. [Figure 8] FIG. 11 is a diagram illustrating a control function of an electronic control device according to a third embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, each embodiment of the present invention will be described in detail with reference to the drawings. Note that in each embodiment, the drawings are appropriately simplified or modified, and the dimensional ratios and shapes of each part are not necessarily drawn accurately. EXAMPLES

[0012] Fig. 1 is a schematic configuration diagram of a vehicle 10 equipped with an electronic control device 80 according to a first embodiment of the present invention, and is also a functional block diagram showing the main parts of control functions for various controls in the vehicle 10. Note that the reference characters in parentheses in Fig. 1 refer to embodiments 2 and 3 described later.

[0013] The vehicle 10 is a hybrid vehicle equipped with an engine 14 and a rotating electric machine MG that function as a driving force source for traveling. The power transmission device 12 includes, in order from the engine 14 side, a clutch K0, a torque converter 16, an automatic transmission 18, and the like, in a transmission case 20 as a non-rotating member. The power transmission device 12 also includes a propeller shaft 26 connected to a transmission output shaft 24 that is an output rotating shaft of the automatic transmission 18, a differential gear 28 connected to the propeller shaft 26, a pair of axles 30 connected to the differential gear 28, and the like. The power transmission device 12 configured in this manner is suitably used in, for example, a FR (front engine, rear drive) type vehicle 10. When the clutch K0 in the power transmission device 12 is engaged (hereinafter, unless otherwise specified, this term will mean fully engaged), the power of the engine 14 (hereinafter, unless otherwise specified, this term will also mean torque or force) is transmitted from the engine connecting shaft 32 connected to the engine 14 to a pair of drive wheels 34, successively via the clutch K0, the torque converter 16, the automatic transmission 18, the propeller shaft 26, the differential gear 28, and a pair of axles 30. In this manner, the power transmission device 12 constitutes a power transmission path from the engine 14 to the drive wheels 34.

[0014] The engine 14 is an internal combustion engine that generates power by burning fuel. The engine 14 is capable of igniting and rotating under its own power even when the engine rotation speed Ne [rpm] is low, and is, for example, a direct injection type internal combustion engine that injects fuel directly into the cylinder.

[0015] The torque converter 16 is provided in a power transmission path between the rotating electric machine MG (and the engine 14) and drive wheels 34. The torque converter 16 is a fluid-type power transmission device that transmits power input to a pump wheel 16a, which is an input side rotating member, via fluid, and outputs the power from a turbine wheel 16b, which is an output side rotating member. The pump wheel 16a is connected to the engine connecting shaft 32 via a clutch K0, and is also directly connected to the rotating electric machine MG. The turbine wheel 16b is directly connected to a transmission input shaft 36, which is an input rotating shaft of the automatic transmission 18.

[0016] The torque converter 16 includes a known lock-up clutch 38 that directly connects the pump wheel 16a and the turbine wheel 16b. The lock-up clutch 38 can mechanically connect the power transmission path between the engine 14, the rotating electric machine MG, and the drive wheels 34. The pump wheel 16a is connected to an oil pump 22. The oil pump 22 is a mechanical oil pump that is driven to rotate by at least one of the engine 14 and the rotating electric machine MG to generate hydraulic oil pressure for performing the shift control of the automatic transmission 18 and the connection / disconnection control of the clutch K0 (transmission torque capacity control). The lock-up clutch 38 is controlled to be connected and disconnected by a hydraulic control circuit 50 provided in the vehicle 10 using the oil pressure generated by the oil pump 22 as a source pressure. For example, when the engine rotation speed Ne is low immediately after the start control of the engine 14 is started, the lock-up clutch 38 is disconnected so that the pulsation of the engine 14 is not transmitted to the drive wheels 34.

[0017] The rotating electric machine MG is a so-called motor generator having a function as a motor that generates mechanical power from electric energy and a function as a generator that generates electric energy from mechanical energy. The rotating electric machine MG functions as a driving force source for generating power for traveling, either as a substitute for the engine 14 or together with the engine 14. The rotating electric machine MG generates electric energy by regeneration from the power generated by the engine 14 or the driven force input from the driving wheels 34, and stores the electric energy in the electricity storage device 54 via the inverter 52. The rotating electric machine MG is connected to a power transmission path between the clutch K0 and the torque converter 16 (i.e., the rotor shaft 40 of the rotating electric machine MG is connected to the clutch K0 and the pump impeller 16a), and power is transmitted between the rotating electric machine MG and the pump impeller 16a. Therefore, the rotating electric machine MG is connected to the transmission input shaft 36 of the automatic transmission 18 so as to be capable of transmitting power without passing through the clutch K0.

[0018] The clutch K0 is a clutch that connects and disconnects the power transmission path between the engine 14 and the rotary electric machine MG. The clutch K0 is, for example, a wet-type multi-plate hydraulic friction engagement device in which a plurality of overlapping friction plates are pressed by a hydraulic actuator, and is controlled to be connected and disconnected by a hydraulic control circuit 50 using the hydraulic pressure generated by the oil pump 22 as the source pressure. In the connection and disconnection control, the transmission torque capacity (engagement force of the clutch K0) Tc [Nm] of the clutch K0 is changed by, for example, adjusting the pressure of a linear solenoid valve or the like in the hydraulic control circuit 50. In the engaged state of the clutch K0, the pump impeller 16a and the engine 14 are rotated integrally via the engine connecting shaft 32. On the other hand, in the released state of the clutch K0, the power transmission between the engine 14 and the pump impeller 16a is interrupted. That is, the engine 14 and the drive wheels 34 are separated by releasing the clutch K0. Since the rotating electric machine MG is connected to the pump impeller 16a, the clutch K0 is provided in the power transmission path between the engine 14 and the rotating electric machine MG, and also functions as a clutch that connects and disconnects the power transmission path.

[0019] The automatic transmission 18 constitutes a part of a power transmission path between the engine 14 and the rotating electric machine MG and the drive wheels 34, and is a transmission that transmits power from a driving power source for traveling (the engine 14 and the rotating electric machine MG) to the drive wheels 34. The automatic transmission 18 is, for example, a known planetary gear type multi-stage transmission in which a plurality of gear stages (gear stages) with different gear ratios (gear ratios) γ (= transmission input rotation speed Nin / transmission output rotation speed Nout) are selectively established, or a known continuously variable transmission in which the gear ratio γ is continuously changed without any step. In the automatic transmission 18, for example, a hydraulic actuator is controlled by a hydraulic control circuit 50 to set a predetermined gear ratio γ in response to the accelerator operation by the driver, the vehicle speed V, etc.

[0020] The vehicle 10 includes an electronic control device 80 that is a control device for the vehicle 10. The electronic control device 80 includes a so-called microcomputer that includes, for example, a CPU, a RAM, a ROM, an input / output interface, and the like, and the CPU executes various controls for the vehicle 10 by performing signal processing according to a program previously stored in the ROM while utilizing the temporary storage function of the RAM. For example, the electronic control device 80 executes output control including start control of the engine 14, drive control of the rotating electric machine MG including regenerative control of the rotating electric machine MG, shift control of the automatic transmission 18, connection / disconnection control of the clutch K0, connection / disconnection control of the lock-up clutch 38, and the like, and is configured to be divided into engine control, rotating electric machine control, hydraulic control, and the like as necessary. The electronic control device 80 corresponds to the "control device" in the present invention.

[0021] The electronic control device 80 receives various signals (e.g., engine rotation speed Ne [rpm] which is the rotation speed of the engine 14, turbine rotation speed sensor 58, output shaft rotation speed sensor 60, MG rotation speed sensor 62, accelerator opening sensor 64, throttle sensor 66, battery sensor 68, etc.) based on detection values ​​from various sensors (e.g., engine rotation speed sensor 56, turbine rotation speed sensor 58, output shaft rotation speed sensor 60, MG rotation speed sensor 62, accelerator opening sensor 64, throttle sensor 66, battery sensor 68, etc.) based on detection values ​​from various sensors. The various signals (e.g., engine rotation speed Ne [rpm] which is the rotation speed of the engine 14, turbine rotation speed Nt [rpm], i.e., transmission input rotation speed Nin [rpm] which is the rotation speed of the transmission input shaft 36, transmission output rotation speed Nout [rpm] which is the rotation speed of the transmission output shaft 24 corresponding to the vehicle speed V, MG rotation speed Nmg [rpm] which is the rotation speed of the rotating electric machine MG, accelerator opening θacc which corresponds to the amount of drive required of the vehicle 10 by the driver, throttle valve opening θth of the electronic throttle valve, state of charge value (ratio of the amount of charge actually stored to the charging capacity) SOC [%] of the storage device 54, etc.) are input.

[0022] The electronic control device 80 outputs, for example, an engine control signal Se for controlling the output of the engine 14, an MG control signal Smg for controlling the operation of the rotating electric machine MG, and a hydraulic control signal Sp for operating electromagnetic valves (solenoid valves) included in the hydraulic control circuit 50 to control the clutch K0, the lock-up clutch 38, and the hydraulic actuators of the automatic transmission 18 to engine control devices such as a throttle actuator and a fuel injection device, the inverter 52, the hydraulic control circuit 50, etc.

[0023] FIG. 2 is a diagram showing an example of an EV / EHV region map used for switching between the motor driving mode and the hybrid driving mode.

[0024] The vehicle 10 switches the driving mode based on the vehicle state indicated by the actual vehicle speed V and the drive demand amount (accelerator opening θacc, etc.) from a predetermined relationship (EV / EHV region map) having, for example, a motor driving region (EV region) and a hybrid driving region (EHV region). When the vehicle state is in the EV region, the driving mode is set to the motor driving mode, and motor driving is performed in which the vehicle runs using only the rotating electric machine MG as a driving force source for running. When the vehicle state is in the EHV region, the driving mode is set to the hybrid driving mode, and hybrid driving is performed in which the vehicle runs using at least the engine 14 as a driving force source for running.

[0025] For example, when the driver depresses the accelerator pedal further, the accelerator opening θacc increases and the vehicle state moves from the EV region to the EHV region, the engine 14 is started and the driving mode is set to the hybrid driving mode. There are two types of engine starting methods for the vehicle 10: an early ignition starting method and a push-start starting method.

[0026] In the early ignition start method, the clutch K0 is engaged and cranked by the rotating electric machine MG, fuel is injected and ignited into the engine 14 before the clutch K0 is synchronized, and when the combustion can be continued, the clutch K0 is once released, and then the clutch K0 is engaged again. In the early ignition start method, fuel is injected and ignited near the compression TDC (Top Dead Center) when the engine speed Ne is low, to start the engine 14. In the push start method, the clutch K0 is engaged and the engine speed Ne is increased by the rotating electric machine MG, and after the clutch K0 is synchronized, fuel is injected and ignited into the engine 14 to start the engine. Compared to the push start method, the early ignition start method uses the combustion torque (engine torque Te) of the engine 14 to start the engine 14, so that the assist torque for cranking by the rotating electric machine MG can be reduced, and the start response is good. The assist torque is a torque transmitted to the engine 14 when the rotating electric machine MG is cranked, and has the same magnitude as the transmission torque capacity (engagement force of the clutch K0) Tc of the clutch K0 during start control of the engine 14. Note that the "start" of the engine 14 referred to here not only refers to the period from when the engine 14 completely explodes (starts operation) until it can operate independently, but also refers to a series of control operations related to engine start until the clutch K0 is fully engaged.

[0027] Fig. 3 is an example of a time chart assuming that the start control of the engine 14 is executed by the early ignition start method by the electronic control device 80 shown in Fig. 1. Note that the K0 oil pressure shown in Fig. 3 is the oil pressure that controls the engagement and disengagement state of the clutch K0, and is the oil pressure supplied to the hydraulic actuator of the clutch K0.

[0028] During motor running in which the vehicle 10 runs using only the rotating electric machine MG as a driving force source for running, the accelerator opening θacc may be increased by, for example, the driver depressing the accelerator pedal further, for example, when the accelerator pedal is changed from a state in which it is not depressed (accelerator opening θacc=0) to a state in which it is depressed (accelerator opening θacc>0).

[0029] At time t0, the accelerator opening θacc is increased to initiate start control of the engine 14 using the early ignition start method. The increased accelerator opening θacc is maintained constant even after the start control of the engine 14 has begun until the start control is completed. The start control completion point is the point at which the clutch K0, which was once released in the early ignition start method, is subsequently re-engaged. With the start of the engine 14 start control, the command pressure for the K0 oil pressure is once set to a high oil pressure after time t0 in order to rapidly close the pack clearance, and is then set to an oil pressure that engages the clutch K0. The actual pressure of the K0 oil pressure rises according to the command pressure for the K0 oil pressure.

[0030] By engaging the clutch K0, the engine 14 is cranked by the rotating electric machine MG from time t1, fuel is injected into the engine 14, and ignition occurs, causing the engine rotation speed Ne to increase. At time t2 when combustion in the engine 14 can continue, a command pressure for the K0 oil pressure to release the clutch K0 is output. The command pressure for the K0 oil pressure is temporarily set to zero after time t2, and then set to an oil pressure (>0) that packs and releases the clutch. The actual pressure of the K0 oil pressure drops according to the command pressure for the K0 oil pressure.

[0031] At time t4, the command pressure of the K0 hydraulic pressure is gradually increased to engage the clutch K0 again, and the actual pressure of the K0 hydraulic pressure increases according to the command pressure. As the actual pressure of the K0 hydraulic pressure increases, for example, the clutch K0 passes through a half-engaged state (slip-engaged state) and then is fully engaged, thereby connecting the engine 14 and the rotating electric machine MG and completing the start-up control of the engine 14. This causes the vehicle 10 to enter a hybrid running state in which the engine 14 and the rotating electric machine MG serve as a driving force source for running.

[0032] However, if the actual pressure of the K0 oil pressure has not dropped sufficiently (i.e., the clutch K0 has not been released) at time t3 when the engine rotation speed Ne and the MG rotation speed Nmg become the same, the inertia of the engine 14 may be transmitted to the rotor shaft 40 of the rotating electric machine MG via the clutch K0, causing a starting shock in the vehicle 10 that exceeds a predetermined allowable range.

[0033] FIG. 4 is a diagram for explaining the relationship between the starting shock generated when starting the engine 14 by the early ignition starting method and the MG rotational speed Nmg. In FIG. 4, three cases with different MG rotational speeds Nmg at the start of the starting control of the engine 14 are illustrated.

[0034] The transmission torque capacity Tc of the clutch K0 changes as shown in FIG. 4 according to the actual pressure of the K0 hydraulic pressure. By engaging the clutch K0, the engine 14 is cranked by the rotating electric machine MG from time t1, fuel is injected into the engine 14 and ignited, and the engine rotational speed Ne increases.

[0035] In the case of case 1 where the MG rotational speed Nmg at the start of the starting control of the engine 14 is the lowest, the clutch K0 synchronizes at time t3a. At the timing when the clutch K0 synchronizes (hereinafter referred to as the "synchronization timing"), the MG rotational speed Nmg is the rotational speed value Nmg1 [rpm]. "The clutch K0 synchronizes" means that the engine rotational speed Ne, which is the same as the rotational speed of the engine connecting shaft 32 on one side of the power transmission path controlled by the clutch K0 for disconnection and connection, and the MG rotational speed Nmg on the other side become the same. The synchronization timing of the clutch K0 is the time when the clutch K0 synchronizes.

[0036] In the case of case 3 where the MG rotational speed Nmg at the start of the starting control of the engine 14 is the highest, the clutch K0 synchronizes at time t3c. At the synchronization timing, the MG rotational speed Nmg is the rotational speed value Nmg3 [rpm].

[0037] In the case of case 2 where the MG rotational speed Nmg at the start of the starting control of the engine 14 is between case 1 and case 3, the clutch K0 synchronizes at time t3b (t3a < t3b < t3c). At the synchronization timing, the MG rotational speed Nmg is the rotational speed value Nmg2 [rpm].

[0038] The higher the MG rotation speed Nmg at the synchronization timing, the longer the period required for the engine rotation speed Ne to increase to the same rotation speed as the MG rotation speed Nmg, i.e., the longer the period from the start of the start control of the engine 14 to the synchronization of the clutch K0. Therefore, the higher the MG rotation speed Nmg at the synchronization timing, the more likely it is that the actual pressure of the K0 hydraulic pressure for temporarily releasing the clutch K0 at the synchronization timing will be lower, and the more likely it is that the transmission torque capacity Tc at the synchronization timing will be smaller. On the other hand, the lower the MG rotation speed Nmg at the synchronization timing, the more likely it is that the actual pressure of the K0 hydraulic pressure for temporarily releasing the clutch K0 at the synchronization timing will be lower, and the more likely it is that the transmission torque capacity Tc at the synchronization timing will be larger.

[0039] When the clutch K0 is synchronized, the clutch K0 transmits the engine torque Te as a disturbance to the rotor shaft 40 of the rotating electric machine MG. If the transmission torque capacity Tc at the synchronization timing is large, the engine torque Te transmitted by the clutch K0 becomes large and the starting shock is likely to fall outside the predetermined allowable range, and if the transmission torque capacity Tc at the synchronization timing is small, the engine torque Te transmitted by the clutch K0 becomes small and the starting shock is likely to fall within the predetermined allowable range.

[0040] Here, in the case where the MG rotation speed Nmg at the synchronization timing is the rotation speed value Nmg2 as in case 2, the transmission torque capacity Tc of the clutch K0 at the synchronization timing is the upper limit value at which the starting shock can be tolerated. In the case of case 1, the starting shock accompanying the starting of the engine 14 by the early ignition start method falls outside a predetermined allowable range. Therefore, in the case of case 1, the execution of the starting control of the engine 14 is suitable for the push start control. In the case of case 3, the starting shock accompanying the starting of the engine 14 by the early ignition start method falls within a predetermined allowable range. Therefore, in the case of case 3, the starting control of the engine 14 is suitable for the early ignition start method. That is, when the MG rotation speed Nmg at the synchronization timing is equal to or higher than the rotation speed value Nmg2, the starting shock accompanying the starting of the engine 14 by the early ignition start method falls within a predetermined allowable range, and when the MG rotation speed Nmg at the synchronization timing is less than the rotation speed value Nmg2, the starting shock accompanying the starting of the engine 14 by the early ignition start method falls outside the predetermined allowable range.

[0041] Returning to FIG. 1, the electronic control device 80 functionally comprises a prediction unit 82, a starting method selection unit 84, and a starting control unit 86.

[0042] The prediction unit 82 calculates (i.e. predicts) the MG rotation speed Nmg at the synchronization timing of the clutch K0 as a synchronous vehicle state value on the assumption that the early ignition start method is executed as the start control of the engine 14 based on the current values ​​of the MG rotation speed Nmg, the system shaft torque Tsys, and the turbine rotation speed Nt. In this specification, the "current" refers to the time point when the start control method of the engine 14 is selected. The system shaft torque Tsys is a required amount of driving torque for traveling on the rotor shaft 40 for the entire drive device (including the engine 14, the clutch K0, and the rotating electric machine MG) of the vehicle 10, and corresponds to, for example, a target value of the input torque input to the torque converter 16, and is a target value of the driving torque output to the drive wheels 34 (torque converter 16) by the engine 14, the clutch K0, and the rotating electric machine MG that form a part of the drive device shown in FIG. 1. For example, the system shaft torque Tsys is obtained by calculating a target value of the output torque at the drive wheels 34 based on the accelerator opening θacc and the vehicle speed V, and converting the calculated target value into torque on the rotor shaft 40 while taking into consideration the transmission loss, the auxiliary load, the gear ratio γ of the automatic transmission 18, the state of charge value SOC of the storage device 54 (in other words, the charge / discharge requirement of the storage device 54), etc.

[0043] For example, the MG rotation speed Nmg at the synchronization timing of the clutch K0 is calculated (predicted) by applying the current values ​​of the MG rotation speed Nmg, system shaft torque Tsys, and turbine rotation speed Nt to a map in which the relationship between the current values ​​of the MG rotation speed Nmg, system shaft torque Tsys, and turbine rotation speed Nt, i.e., the values ​​at the time when the starting method of the engine 14 is selected, and the MG rotation speed (predicted value) Nmg at the synchronization timing of the clutch K0 is predetermined by experiment or design. Since the control of the K0 oil pressure from the start of the start control of the engine 14 to the synchronization timing of the clutch K0 is predetermined, the control of the operating state of the clutch K0 (including the state of the transmission torque capacity Tc) is predetermined, and the MG rotation speed Nmg at the synchronization timing of the clutch K0 can be calculated based on the current values ​​of the MG rotation speed Nmg, system shaft torque Tsys, and turbine rotation speed Nt.

[0044] The starting method selection unit 84 judges whether the MG rotation speed Nmg at the synchronous timing predicted by the prediction unit 82 is equal to or greater than a predetermined MG rotation speed judgment value Nmg_jdg [rpm]. The predetermined MG rotation speed judgment value Nmg_jdg is a judgment value that is experimentally or design-wise determined in advance to judge (predict) whether a starting shock occurs within a predetermined allowable range when starting control of the engine 14 is performed by the early ignition starting method. For example, it is the rotation speed value Nmg2 in FIG. 4 described above. If it is determined that the MG rotation speed Nmg at the predicted synchronous timing is equal to or greater than the predetermined MG rotation speed judgment value Nmg_jdg, the starting method selection unit 84 selects the early ignition starting method as the starting control of the engine 14. If it is determined that the MG rotation speed Nmg at the predicted synchronous timing is less than the predetermined MG rotation speed judgment value Nmg_jdg, the starting method selection unit 84 selects the push start method as the starting control of the engine 14.

[0045] When the starting method selection unit 84 selects the early ignition starting method, the starting control unit 86 executes starting control of the engine 14 using the early ignition starting method. When the starting method selection unit 84 selects the push starting method, the starting control unit 86 executes starting control of the engine 14 using the push starting method.

[0046] Fig. 5 is an example of a flowchart illustrating a main part of the control operation of the electronic control device 80 shown in Fig. 1. For example, when it is determined to execute start control of the engine 14 while the vehicle 10 is running on the motor, the flowchart of Fig. 5 is executed.

[0047] In step S10, which corresponds to the function of the prediction unit 82, the MG rotation speed Nmg at the synchronization timing of the clutch K0 on the assumption that the early ignition start method is executed as the start control of the engine 14 is calculated (i.e., predicted) based on the current values ​​of the MG rotation speed Nmg, the system shaft torque Tsys, and the turbine rotation speed Nt. Then, step S20 is executed.

[0048] In step S20, which corresponds to the function of the starting method selection unit 84, it is determined whether the MG rotation speed Nmg predicted in step S10 is equal to or greater than a predetermined MG rotation speed determination value Nmg_jdg. If the determination in step S20 is positive, step S30 is executed. If the determination in step S20 is negative, step S50 is executed.

[0049] In step S30, which corresponds to the function of the starting method selection unit 84, the early ignition starting method is selected as the starting control of the engine 14. Then, step S40 is executed.

[0050] In step S40, which corresponds to the function of the start control section 86, the engine 14 is started using the early ignition start strategy. Then the process returns.

[0051] In step S50, which corresponds to the function of the starting method selection unit 84, the push start method is selected as the starting control of the engine 14. Then, step S60 is executed.

[0052] In step S60, which corresponds to the function of the starting control section 86, the engine 14 is started by the push start method. Then, the process returns.

[0053] According to this embodiment, (a) when a method of starting control of the engine 14 is selected, assuming that an early ignition start method is executed as the starting control of the engine 14 based on the values ​​of the MG rotation speed Nmg, the system shaft torque Tsys input to the torque converter 16, and the turbine rotation speed Nt of the torque converter 16 at the time when the method of starting control of the engine 14 is selected, the MG rotation speed Nmg at the synchronization timing of the clutch K0 is calculated as a synchronous vehicle state value, and then the MG rotation speed Nmg, which is the calculated synchronous vehicle state value, is compared with a predetermined MG rotation speed judgment value Nmg_jdg to predict whether the starting shock is within a predetermined allowable range, (b) if it is predicted that the starting shock is within the predetermined allowable range, the early ignition start method is selected as the starting control of the engine 14, and (c) if it is predicted that the starting shock is outside the predetermined allowable range, the push start method is selected as the starting control of the engine 14. If the start shock caused by starting the engine using the early ignition start method is predicted to be within a predetermined tolerance range, the early ignition start method is selected, and if it is predicted to be outside the predetermined tolerance range, the push start method is selected. This makes it possible to improve the response of engine start while suppressing the start shock caused by starting the engine 14. EXAMPLES

[0054] Now, a second embodiment of the present invention will be described.

[0055] The configuration of a vehicle 110 in this embodiment is substantially the same as the configuration of the vehicle 10 in the above-described first embodiment, except that an electronic control unit 180 is provided instead of the electronic control unit 80 (see FIG. 1).

[0056] Fig. 6 is an example of a time chart assuming that the start control of the engine 14 is executed by the early ignition start method by the electronic control device 180 according to the second embodiment of the present invention. Fig. 6 corresponds to Fig. 3 in the first embodiment described above.

[0057] Fig. 6 is substantially the same as the time chart of Fig. 3 in the first embodiment described above, but differs in that the increased accelerator opening θacc is maintained constant even after the start control of the engine 14 is initiated until the start control is completed in Fig. 3, whereas in Fig. 6 the accelerator opening θacc is set to zero before the start control of the engine 14 is completed. Therefore, the following description will focus on the parts that differ from Fig. 3, and parts that are substantially the same as Fig. 3 will be denoted by the same reference numerals and description thereof will be omitted as appropriate.

[0058] During motor running in which the vehicle 110 runs using only the rotating electric machine MG as a driving force source for running, for example, the accelerator opening θacc is increased by the driver depressing the accelerator pedal further. At time t0, the increase in the accelerator opening θacc initiates start control of the engine 14 using the early ignition start method. The increased accelerator opening θacc is set to zero after being maintained for a predetermined period T1 after the start of the start control of the engine 14. The predetermined period T1 is a period that is preset, for example, when the driver depresses the accelerator pedal further and then releases the accelerator opening θacc to return to zero. A command value for the system shaft torque Tsys is calculated according to the predetermined period T1, and the actual value of the system shaft torque Tsys can be predicted according to this command value.

[0059] Assuming that the specified period T1 is set in advance, the MG rotation speed Nmg at the synchronization timing of the clutch K0 can be calculated by applying the current values ​​of the MG rotation speed Nmg, system shaft torque Tsys, and turbine rotation speed Nt to a map in which the relationship between the current values ​​of the MG rotation speed Nmg, system shaft torque Tsys, and turbine rotation speed Nt, i.e., the values ​​at the time when the starting method of the engine 14 is selected, and the MG rotation speed (predicted value) Nmg at the synchronization timing of the clutch K0 is predetermined experimentally or by design.

[0060] The electronic control device 180 has substantially the same configuration as the electronic control device 80 in the above-described first embodiment, but differs in that a prediction unit 182 is provided instead of the prediction unit 82 (see FIG. 1). Therefore, in this embodiment, the differences from the above-described first embodiment will be mainly described, and descriptions of parts that are substantially common in function to the above-described first embodiment will be omitted as appropriate.

[0061] The prediction unit 182 calculates (i.e., predicts) the MG rotational speed Nmg at the synchronization timing of the clutch K0 as a synchronization vehicle state value based on the current values ​​of the MG rotational speed Nmg, the system shaft torque Tsys, and the turbine rotational speed Nt, assuming that the early ignition start method is executed as the start control of the engine 14, assuming that the predetermined period T1 is set in advance.

[0062] The starting method selection unit 84 determines whether the MG rotation speed Nmg at the synchronization timing predicted by the prediction unit 182 is equal to or greater than a predetermined MG rotation speed determination value Nmg_jdg. If it is determined that the MG rotation speed Nmg at the predicted synchronization timing is equal to or greater than the predetermined MG rotation speed determination value Nmg_jdg, the starting method selection unit 84 selects the early ignition start method as the start control of the engine 14. If it is determined that the MG rotation speed Nmg at the predicted synchronization timing is less than the predetermined MG rotation speed determination value Nmg_jdg, the starting method selection unit 84 selects the push start method as the start control of the engine 14.

[0063] When the starting method selection unit 84 selects the early ignition starting method, the starting control unit 86 executes starting control of the engine 14 using the early ignition starting method. When the starting method selection unit 84 selects the push starting method, the starting control unit 86 executes starting control of the engine 14 using the push starting method.

[0064] Fig. 7 is an example of a flowchart for explaining the main control operations of the electronic control device 180 according to this embodiment. The flowchart in Fig. 7 is substantially the same as the flowchart in Fig. 5 in the above-described first embodiment, except that step S110 is used instead of step S10. Therefore, the same reference numerals are used for the steps in the flowchart in Fig. 5 that are substantially the same in function, and the description thereof will be omitted as appropriate.

[0065] In step S110, which corresponds to the function of the prediction unit 182, the MG rotation speed Nmg at the synchronization timing of the clutch K0 is calculated (i.e., predicted) based on the current values ​​of the MG rotation speed Nmg, the system shaft torque Tsys, and the turbine rotation speed Nt, on the assumption that the accelerator pedal is released after a predetermined period T1 has elapsed since the driver further depresses the accelerator pedal to decide to start the engine 14. Then, step S20 is executed. After step S20, the same contents as those of the steps in the flowchart of FIG. 5 are executed.

[0066] According to this embodiment, even if the start control of the engine 14 is started by an increase in the accelerator opening θacc and the accelerator opening θacc is set to zero after the predetermined period T1 has elapsed since the start of the start control, if it is predicted that the start shock caused by the engine start using the early ignition start method is within a predetermined allowable range, the early ignition start method is selected, and if it is predicted that the start shock caused by the engine start using the early ignition start method is outside the predetermined allowable range, the push start method is selected. This makes it possible to improve the response of the engine start while suppressing the start shock caused by the start of the engine 14. Note that, in reality, there may be cases where the accelerator opening θacc is set to zero after the engine start control using the early ignition start method has been started and before the predetermined period T1 has elapsed. In such a case, the start response is reduced, but the electronic control device 180 can reduce the start shock by changing the K0 hydraulic pressure (release pressure) that releases the clutch K0 so as to be lowered. In addition, it is also possible to make it easier to select the push start method than the early ignition start method by previously setting the predetermined period T1 to a short period, thereby making it difficult to generate the start shock caused by the engine start using the early ignition start method. EXAMPLES

[0067] Hereinafter, a third embodiment of the present invention will be described.

[0068] The configuration of a vehicle 210 in this embodiment is substantially the same as the configuration of the vehicle 10 in the above-described first embodiment, except that an electronic control unit 280 is provided instead of the electronic control unit 80 (see FIG. 1).

[0069] FIG. 8 is a diagram for explaining the control function of an electronic control device 280 according to a third embodiment of the present invention. The electronic control device 280 has substantially the same configuration as the electronic control device 80 in the first embodiment described above, but differs in that, assuming that the early ignition start method is executed as the start control of the engine 14, the system shaft torque Tsys is predicted as the synchronous vehicle state value at the synchronization timing of the clutch K0, instead of the MG rotation speed Nmg, and the predicted system shaft torque Tsys is compared with a predetermined shaft torque judgment value Tsys_jdg to select the start control method of the engine 14. FIG. 8 is not the functional block diagram shown in FIG. 1 in the first embodiment, but is an example of a logic diagram showing the logic procedure when selecting the start control method of the engine 14.

[0070] When selecting a start control method for the engine 14, first, based on the current values ​​of the MG rotation speed Nmg, the system shaft torque Tsys, and the turbine rotation speed Nt, a transmission torque capacity Tc of the clutch K0 at the synchronization timing of the clutch K0 when it is assumed that the early ignition start method is executed as the start control of the engine 14 is calculated (i.e., predicted). Also, based on the current values ​​of the MG rotation speed Nmg, the system shaft torque Tsys, and the turbine rotation speed Nt, a system shaft torque (predicted value) Tsys at the synchronization timing of the clutch K0 when it is assumed that the early ignition start method is executed as the start control of the engine 14 is calculated (i.e., predicted) as a synchronous vehicle state value.

[0071] The larger the transmission torque capacity Tc of the clutch K0 at the synchronization timing, the larger the starting shock is likely to be in the early ignition start method. For example, the electronic control device 280 has a system shaft torque map MAP1 that outputs a predetermined shaft torque judgment value Tsys_jdg when the transmission torque capacity Tc of the clutch K0 at the synchronization timing is equal to or smaller than a predetermined torque capacity, and a system shaft torque map MAP2 that outputs the predetermined shaft torque judgment value Tsys_jdg when the transmission torque capacity Tc of the clutch K0 at the synchronization timing exceeds the predetermined torque capacity. The predetermined torque capacity is a torque value that is determined in advance experimentally or by design, and is determined in order to select whether the map used to output the predetermined shaft torque judgment value Tsys_jdg is the system shaft torque map MAP1 or the system shaft torque map MAP2.

[0072] The predetermined shaft torque judgment value Tsys_jdg is a judgment value that is experimentally or design-predetermined in order to determine (predict) whether the start shock occurring when the engine 14 is started by the early ignition start method is within a predetermined allowable range. The system shaft torque map MAP1 and the system shaft torque map MAP2 are maps in which the relationship between the current values ​​of the MG rotation speed Nmg, the system shaft torque Tsys, and the turbine rotation speed Nt and the predetermined shaft torque judgment value Tsys_jdg is experimentally or design-predetermined in advance. The predetermined shaft torque judgment value Tsys_jdg output by the system shaft torque map MAP2 is set to be larger than the predetermined shaft torque judgment value Tsys_jdg output by the system shaft torque map MAP1. Therefore, when the transmission torque capacity Tc of the clutch K0 at the synchronization timing is large compared to when the transmission torque capacity Tc of the clutch K0 at the synchronization timing is small, the predetermined shaft torque judgment value Tsys_jdg is switched to a large value.

[0073] The system shaft torque Tsys at the synchronization timing is compared with a predetermined shaft torque judgment value Tsys_jdg, which is a judgment value output from either the system shaft torque map MAP1 or the system shaft torque map MAP2, and if the calculated system shaft torque Tsys at the synchronization timing is greater than the predetermined shaft torque judgment value Tsys_jdg, the early ignition start method is selected, that is, the early ignition start method is permitted. On the other hand, if the calculated system shaft torque Tsys at the synchronization timing is smaller than the predetermined shaft torque judgment value Tsys_jdg, the push start method is selected, that is, the early ignition start method is not permitted. The predetermined shaft torque judgment value Tsys_jdg, which is a judgment value output from either the system shaft torque map MAP1 or the system shaft torque map MAP2, is a torque lower limit value of the system shaft torque Tsys that is experimentally or design-predetermined so that the starting shock in the early ignition start method is within a predetermined allowable range. In other words, the system shaft torque map MAP1 and the system shaft torque map MAP2 are maps in which the predetermined shaft torque determination value Tsys_jdg and the transmission torque capacity Tc of the clutch K0 at the synchronization timing are determined in advance experimentally or by design.

[0074] According to this embodiment, (a) when the method of starting control of the engine 14 is selected, the system shaft torque Tsys at the synchronization timing of the clutch K0 is calculated as a synchronous vehicle state value when the early ignition start method is executed as the starting control of the engine 14 based on the current values ​​of the MG rotation speed Nmg, the system shaft torque Tsys input to the torque converter 16, and the turbine rotation speed Nt of the torque converter 16. Then, the system shaft torque Tsys, which is the calculated synchronous vehicle state value, is compared with a predetermined shaft torque judgment value Tsys_jdg to predict whether the starting shock is within a predetermined allowable range. (b) When the starting shock is predicted to be within the predetermined allowable range, the early ignition start method is selected as the starting control of the engine 14. (c) When the starting shock is predicted to be outside the predetermined allowable range, the push start method is selected as the starting control of the engine 14. When the starting shock generated by the early ignition start method is predicted to be within the predetermined allowable range, the early ignition start method is selected, and when it is predicted to be outside the predetermined allowable range, the push start method is selected. This makes it possible to improve the response of the engine start while suppressing the start shock that occurs when the engine 14 is started.

[0075] According to this embodiment, the predetermined shaft torque judgment value Tsys_jdg is switched according to the predicted value of the transmission torque capacity Tc of the clutch K0 at the synchronization timing of the clutch K0. The magnitude of the engine torque Te transmitted by the clutch K0 as a disturbance changes according to the transmission torque capacity Tc of the clutch K0 at the synchronization timing of the clutch K0. Therefore, by switching the judgment value for predicting whether the starting shock is within a predetermined allowable range according to the transmission torque capacity Tc of the clutch K0, the accuracy of prediction as to whether the starting shock is within a predetermined allowable range is improved.

[0076] Although the embodiment of the present invention has been described in detail above with reference to the drawings, the present invention can be applied to other embodiments.

[0077] In the above-described first and second embodiments, when the method of starting control of the engine 14 is selected, the MG rotation speed Nmg at the synchronization timing of the clutch K0 is calculated as the synchronous vehicle state value on the assumption that the early ignition start method is executed as the start control of the engine 14 based on the current values ​​of the MG rotation speed Nmg, the system shaft torque Tsys input to the torque converter 16, and the turbine rotation speed Nt of the torque converter 16. However, this is not limited to the above. For example, as in the above-described third embodiment, when the method of starting control of the engine 14 is selected, the system shaft torque Tsys at the synchronization timing of the clutch K0 may be calculated as the synchronous vehicle state value on the assumption that the early ignition start method is executed as the start control of the engine 14 based on the current values ​​of the MG rotation speed Nmg, the system shaft torque Tsys input to the torque converter 16, and the turbine rotation speed Nt of the torque converter 16. In this case, (a) the system axle torque Tsys, which is the calculated synchronous vehicle state value, is compared with a predetermined predetermined axle torque judgment value Tsys_jdg to predict whether the starting shock is within a predetermined allowable range, (b) if the starting shock is predicted to be within the predetermined allowable range, the early ignition start method is selected as the starting control of the engine 14, and (c) if the starting shock is predicted to be outside the predetermined allowable range, the push start method is selected as the starting control of the engine 14. The predetermined axle torque judgment value Tsys_jdg in this case is a judgment value that is determined in advance experimentally or by design in order to determine whether the starting shock is within the predetermined allowable range when the starting control of the engine 14 is executed by the early ignition start method.

[0078] In the above-described third embodiment, the predetermined shaft torque determination value Tsys_jdg for determining whether or not the starting shock is within a predetermined allowable range is switched in response to a predicted value of the transmission torque capacity Tc of the clutch K0 at the synchronization timing of the clutch K0, but the present invention is not limited to this. For example, in the first and second embodiments, the predetermined MG rotation speed determination value Nmg_jdg for determining whether or not the starting shock is within a predetermined allowable range may be switched in response to a predicted value of the transmission torque capacity Tc of the clutch K0 at the synchronization timing of the clutch K0.

[0079] It should be noted that the above is merely an embodiment of the present invention, and the present invention can be embodied in various forms with various modifications and improvements based on the knowledge of those skilled in the art without departing from the spirit of the present invention. [Explanation of symbols]

[0080] 10, 110, 210: Vehicle 14: Engine (power source for driving) 16: Torque converter 34: Drive wheel 80, 180, 280: Electronic control device (control device) K0: Clutch MG: Rotating motor (power source for running) Nmg: MG rotation speed (rotation speed of the rotating electrical machine) Nt: Turbine rotation speed Tsys: System shaft torque

Claims

[Claim 1] A control device for a vehicle including an engine and a rotating electric machine as a driving force source for running, a clutch that connects and disconnects a power transmission path between the engine and the rotating electric machine, and a torque converter that transmits power of the driving force source for running to a driving wheel, When selecting a start control method for the engine from an early ignition start method in which the clutch is engaged and cranked by the rotating electric machine, fuel is injected into the engine before synchronization of the clutch, and when combustion can continue, the clutch is temporarily released and then the clutch is re-engaged, and a push start method in which the clutch is engaged and the engine rotation speed is increased by the rotating electric machine, and after synchronization of the clutch, fuel is injected into the engine, ignited, and the engine is started, predicting whether or not a start shock that would occur if the early ignition start method were executed as the start control for the engine is within a predetermined allowable range based on values ​​of the rotation speed of the rotating electric machine, the system shaft torque input to the torque converter, and the turbine rotation speed of the torque converter at the time when the start control method for the engine is selected, When the start shock is predicted to be within the predetermined allowable range, the early ignition start method is selected as the start control of the engine; When the starting shock is predicted to be outside the predetermined allowable range, the push start method is selected as the starting control of the engine. A vehicle control device comprising:

Images