JP2022113051A - vehicle controller - Google Patents

Abstract

To provide a vehicle controller capable of suppressing the occurrence of pull-in shock upon starting an engine.SOLUTION: When an engine is started within a prescribed period from a time point when determining that an engine start method has been switched from an early ignition start method to a push start method, a vehicle controller executes the following: (a) calculating, as available output torque, traveling driving torque out of the output torque of a rotary electric machine on the basis of the transmission torque capacity of a clutch when it is assumed that the push start method has been executed; (b) calculating, as demand torque, the amount of traveling driving torque demanded of a traveling driving force source on the basis of the transmission torque capacity of the clutch when it is assumed that the early ignition start method has been executed; and (c) executing the start control of the engine by using the early ignition start method when the available output torque is insufficient for the demand torque.SELECTED DRAWING: Figure 1

Description

The present invention relates to a control device for a vehicle having an engine and a rotating electric machine connected to the engine via a clutch.

BACKGROUND ART A control device for a vehicle is known that includes an engine and a rotating electrical machine as a driving force source for running, and a clutch that connects and disconnects a power transmission path between the engine and the rotating electrical machine. For example, a vehicle control device described in Patent Document 1 is one of them. Patent Literature 1 discloses a method for controlling the start of an engine by engaging a clutch and cranking with a rotating electric machine, injecting fuel into the engine before synchronizing the clutch, igniting the engine, and once the combustion can be continued. An early spark start strategy is disclosed that releases the clutch and then re-engages the clutch.

WO2014/97376

By the way, when a vehicle using a rotating electrical machine as a driving force source for running is running, for example, when the rotational speed of the rotating electrical machine is low, if the engine is started by the early ignition start method, the engine rotational speed will increase 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, causing a start shock exceeding the allowable range. Therefore, if there is a possibility that such a start-up shock may occur, it is desirable 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 speed by a rotating electrical machine, and after the clutch is synchronized, fuel is injected into the engine and ignited to start the engine. Compared to the early ignition starting method, the push starting method reduces the starting shock associated with starting the engine, but requires a larger assist torque for starting the engine. Therefore, for example, if the engine is started unconditionally by the push-start method when the rotation speed of the rotating electric machine is low, the output torque of the rotating electric machine will be insufficient for the necessary drive torque for running and the assist torque for starting the engine. As a result, there is a case where a pull-in shock occurs when the engine is started due to a drop in the drive torque for running.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a vehicle control apparatus capable of suppressing the occurrence of a pull-in shock when the engine is started.

The gist of the present invention is a control device for a vehicle comprising an engine and a rotating electric machine as driving force sources for running, and a clutch for connecting and disconnecting a power transmission path between the engine and the rotating electric machine. When the engine is started within a predetermined period after it is determined that the engine starting method has been switched from the early ignition start method to the push start method, (a) the engine is started by the push start method; Based on the transmission torque capacity of the clutch when it is assumed that the control is executed, the driving torque for running out of the output torque of the rotating electrical machine is calculated as the output possible torque, and (b) the early ignition start method. (c) calculating the amount of drive torque required for the drive power source as the required torque based on the transmission torque capacity of the clutch when it is assumed that the engine start control is executed; The engine start control is executed by the early ignition starting method when the torque is insufficient for the required torque.

According to the vehicle control device of the present invention, when the engine is started within a predetermined period after it is determined that the engine starting method has been switched from the early ignition starting method to the push starting method, (a ) Based on the transmission torque capacity of the clutch when it is assumed that the engine start control is executed by the push-start method, the driving torque for traveling out of the output torque of the rotating electric machine is calculated as the output possible torque. and (b) requesting an amount of driving torque required for driving the driving power source based on the transmission torque capacity of the clutch when it is assumed that the engine is started under the early ignition starting method. (c) when the possible output torque is insufficient with respect to the required torque, the engine starting control is executed by the early ignition starting method. In this way, when the engine is started within a predetermined period after it is determined that the engine starting method has been switched from the early ignition starting method to the push start method, the engine start control is actually performed by the push start method. is executed, the driving torque for running out of the output torque of the rotary electric machine is insufficient for the driving torque required for the driving power source for running, and a pull-in shock occurs when the engine is started. , the engine starting control is executed by the early ignition starting method regardless of the starting method determined to be switched. This suppresses the occurrence of a pull-in shock when the engine is started.

1 is a schematic configuration diagram of a vehicle equipped with an electronic control device according to an embodiment of the present invention, and a functional block diagram showing main parts of control functions for various controls in the vehicle; FIG. FIG. 4 is a diagram showing an example of an EV/EHV area map used for switching between motor driving mode and hybrid driving mode; FIG. 4 is a diagram for explaining the relationship between a starting shock that occurs when an engine is started by an early ignition starting method and the rotational speed of a rotating electric machine; FIG. 2 is an example of a flow chart for explaining the main part of the control operation of the electronic control unit shown in FIG. 1; FIG. FIG. 2 is an example of a time chart for explaining the control operation of the electronic control unit shown in FIG. 1; FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following examples, the drawings are appropriately simplified or modified, and the dimensional ratios, shapes, etc. of each part are not necessarily drawn accurately.

FIG. 1 is a schematic configuration diagram of a vehicle 10 equipped with an electronic control unit 80 according to an embodiment of the present invention, and is a functional block diagram showing essential control functions for various controls in the vehicle 10. As shown in FIG.

The vehicle 10 is a hybrid vehicle that includes an engine 14 that functions as a driving force source for running and a rotating electric machine MG. 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 which is an output rotary shaft of the automatic transmission 18, a differential gear 28 connected to the propeller shaft 26, and a differential gear 28 connected to the differential gear 28. A pair of axles 30 and the like are also provided. The power transmission device 12 configured in this manner is preferably used in, for example, an FR (front engine/rear drive) type vehicle 10 . When the clutch K0 in the power transmission device 12 is engaged (hereinafter, this means complete engagement unless otherwise specified), the power of the engine 14 (hereinafter, torque unless otherwise specified) is applied. and force are synonymous.) is sequentially transmitted from an engine connecting shaft 32 connected to the engine 14 via a clutch K0, a torque converter 16, an automatic transmission 18, a propeller shaft 26, a differential gear 28, a pair of axles 30, and the like. is transmitted to a pair of driving wheels 34. Thus, the power transmission device 12 constitutes a power transmission path from the engine 14 to the drive wheels 34 .

The engine 14 is an internal combustion engine that generates power by burning fuel. The engine 14 can be ignited at a low engine rotation speed Ne [rpm] to rotate by itself.

The torque converter 16 is provided in a power transmission path between the rotary electric machine MG (and the engine 14) and the drive wheels 34. The torque converter 16 is a hydrodynamic transmission device that outputs power from a turbine impeller 16b that is an output-side rotating member by transmitting power input to a pump impeller 16a that is an input-side rotating member via fluid. The pump impeller 16a is coupled to the engine coupling shaft 32 via the clutch K0 and directly coupled to the rotary electric machine MG. The turbine wheel 16 b is directly connected to a transmission input shaft 36 that is an input rotating shaft of the automatic transmission 18 .

The torque converter 16 includes a known lockup clutch 38 that directly connects the pump impeller 16a and the turbine impeller 16b. The lockup clutch 38 can mechanically connect the power transmission path between the engine 14 and the rotary electric machine MG and the drive wheels 34 . An oil pump 22 is connected to the pump impeller 16a. The oil pump 22 is rotationally driven by at least one of the engine 14 and the rotary electric machine MG, and provides working oil pressure for executing shift control of the automatic transmission 18, connection/disconnection control of the clutch K0 (transmission torque capacity control), and the like. It is a mechanical oil pump that generates The lockup clutch 38 is controlled by a hydraulic control circuit 50 provided in the vehicle 10 using hydraulic 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 lockup clutch 38 is disconnected so that the pulsation of the engine 14 is not transmitted to the drive wheels 34 .

The rotary electric machine MG is, for example, a so-called motor generator having a function as a motor that generates mechanical power from electrical energy and a function as a generator that generates electrical energy from mechanical energy. The rotary electric machine MG functions as a driving force source for driving, instead of the engine 14 or together with the engine 14, to generate driving power for driving. The rotary electric machine MG regenerates electric energy from the power generated by the engine 14 and the driven force input from the driving wheels 34, and accumulates the electric energy in the power storage device 54 via the inverter 52. perform the operation. The rotary electric machine MG is connected to the power transmission path between the clutch K0 and the torque converter 16 (that is, the rotor shaft 40 of the rotary electric machine MG is connected to the clutch K0 and the pump impeller 16a). and the pump impeller 16a. Therefore, the rotary electric machine MG is connected to the transmission input shaft 36 of the automatic transmission 18 without interposing the clutch K0 so as to be able to transmit power. The MG torque Tmg, which is the output torque of the rotary electric machine MG, is controlled by an electronic control unit 80, which will be described later.

Clutch K0 is a clutch that connects and disconnects a power transmission path between engine 14 and rotary electric machine MG. The clutch K0 is, for example, a wet multi-plate type hydraulic friction engagement device in which a plurality of friction plates that are superimposed on each other are pressed by a hydraulic actuator. is controlled by In the connection/disconnection control, the transmission torque capacity of the clutch K0 (the engagement force of the clutch K0) Tc [Nm] is changed by adjusting the pressure of a linear solenoid valve or the like in the hydraulic control circuit 50, for example. In the engaged state of the clutch K<b>0 , the pump impeller 16 a and the engine 14 are integrally rotated through the engine connecting shaft 32 . On the other hand, when the clutch K0 is released, power transmission between the engine 14 and the pump impeller 16a is cut off. That is, the engine 14 and the drive wheels 34 are separated by releasing the clutch K0. Since the rotating electrical 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 electrical machine MG, and functions as a clutch that connects and disconnects the power transmission path.

The automatic transmission 18 constitutes a part of a power transmission path between the engine 14 and the rotary electric machine MG and the drive wheels 34, and transmits power from the drive power source (the engine 14 and the rotary electric machine MG) to the drive wheels 34. It is a transmission that transmits to The automatic transmission 18 is, for example, a known planetary gear ratio (gear ratio) γ (=transmission input rotational speed Nin/transmission output rotational speed Nout) that selectively establishes a plurality of shift stages (gear stages) that differ. A gear-type multi-stage transmission, or a known continuously variable transmission in which the gear ratio γ is steplessly and continuously changed. 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 according to the driver's accelerator operation, vehicle speed V, and the like.

The vehicle 10 includes an electronic control device 80 that is a control device of the vehicle 10 . The electronic control unit 80 includes, for example, a so-called microcomputer having a CPU, a RAM, a ROM, and an input/output interface. Various controls of the vehicle 10 are executed by performing signal processing. For example, the electronic control unit 80 performs output control including start control of the engine 14, drive control of the rotary electric machine MG including regeneration control of the rotary electric machine MG, shift control of the automatic transmission 18, connection/disengagement control of the clutch K0, lockup control, It is designed to execute connection/disengagement control of the clutch 38, etc., and is configured separately for engine control, rotary electric machine control, hydraulic pressure control, etc., as required. The electronic control device 80 corresponds to the "control device" in the present invention.

The electronic control unit 80 includes various sensors (for example, an engine rotation speed sensor 56, a turbine rotation speed sensor 58, an output shaft rotation speed sensor 60, an MG rotation speed sensor 62, an accelerator opening sensor 64, a throttle sensor 66, a battery sensor 68, and the like. ) based on detected values (for example, 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; rpm], the transmission output rotation speed Nout [rpm] that is the rotation speed of the transmission output shaft 24 corresponding to the vehicle speed V, the MG rotation speed Nmg [rpm] that is the rotation speed of the rotary electric machine MG, The accelerator opening θacc corresponding to the drive demand amount, the throttle valve opening θth of the electronic throttle valve, the state of charge value of the power storage device 54 (the ratio of the amount of charge actually stored to the charge capacity) SOC [%], etc.) , respectively.

From the electronic control unit 80, 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 rotary electric machine MG, hydraulic pressures of the clutch K0, the lockup clutch 38, and the automatic transmission 18 A hydraulic control signal Sp for operating a solenoid valve included in the hydraulic control circuit 50 to control the actuator, etc., is supplied to an engine control device such as a throttle actuator and a fuel injection device, an inverter 52, and a hydraulic control circuit. 50, etc., respectively.

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

The vehicle 10 determines the actual vehicle speed V and the drive demand amount (accelerator opening degree θacc etc.), the driving mode is switched based on the vehicle state. When the vehicle state is in the EV region, motor running is performed in which the running mode is set to the motor running mode and only the rotary electric machine MG is used as the 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 at least the engine 14 is used as the driving force source for driving.

For example, when the driver further depresses the accelerator pedal to increase the accelerator opening θacc and the vehicle state moves from the EV region to the EHV region, the engine 14 is started and the running mode is changed to the hybrid running mode. The engine starting method of the vehicle 10 includes an early ignition starting method and a push starting method.

In the early ignition starting method, the clutch K0 is engaged and cranking is performed by the rotary electric machine MG, fuel is injected and ignited into the engine 14 before synchronization of the clutch K0, and the clutch K0 is released once when combustion can be continued. and then engage the clutch K0 again. In the early ignition starting method, fuel is injected and ignited near the compression TDC (Top Dead Center) when the engine speed Ne is low, and the engine 14 is started. The push-start method is a method in which the clutch K0 is engaged to increase the engine rotation speed Ne by the rotary electric machine MG, and after the clutch K0 is synchronized, fuel is injected into the engine 14 and ignited 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 the rotary electric machine MG can be reduced, Good responsiveness. The assist torque is a torque transmitted to the engine 14 when the rotary electric machine MG cranks, 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. be. Note that the "starting" of the engine 14 referred to here means not only until the engine 14 fully explodes (starts operation) and becomes capable of self-sustaining operation, but also until the clutch K0 is completely engaged. It is also a series of control operations related to engine start-up.

FIG. 3 is a diagram for explaining the relationship between the starting shock generated when the engine 14 is started by the early ignition starting method and the MG rotation speed Nmg. FIG. 3 is an example of a time chart when it is assumed that the electronic control unit 80 shown in FIG. Three cases with different Nmg are illustrated. Note that the K0 hydraulic pressure shown in FIG. 3 is the hydraulic pressure that controls the connection/disconnection state of the clutch K0, and is the hydraulic pressure that is supplied to the hydraulic actuator of the clutch K0.

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

At the time x0, the start control of the engine 14 by the early ignition starting method is started by increasing the accelerator opening θacc. The increased accelerator opening .theta.acc is maintained constant even after the start control of the engine 14 is started until the start control is completed. The starting control completion time is the time when the clutch K0 once released in the early ignition starting method is re-engaged after that. When the start control of the engine 14 is started, the command pressure of the K0 oil pressure is once set to a high oil pressure for packing to quickly close the pack clearance after the time x0, and then set to the oil pressure to engage the clutch K0. . The actual pressure of the K0 oil pressure increases according to the command pressure of the K0 oil pressure.

Due to the engagement of the clutch K0, the engine 14 is cranked by the rotary electric machine MG from the time x1, fuel is injected into the engine 14 and ignited, and the engine speed Ne increases. At the time x2 when the combustion of the engine 14 can be continued, the command pressure of the K0 oil pressure for disengaging the clutch K0 is output. The indicated pressure of the K0 oil pressure is temporarily set to zero after the time x2, and then set to the oil pressure (>0) for the packed and released state. The actual pressure of the K0 oil pressure decreases according to the command pressure of the K0 oil pressure.

At time x4, the commanded pressure of the K0 oil pressure is gently increased in order to engage the clutch K0 again, and the actual pressure of the K0 oil pressure increases according to the commanded pressure. By increasing the actual pressure of the K0 hydraulic pressure, for example, the clutch K0 is brought into a fully engaged state through a half-engaged state (slip engaged state), so that the engine 14 and the rotary electric machine MG are connected and the engine 14 is started. Control is complete. As a result, the vehicle 10 runs in a hybrid mode in which the engine 14 and the rotary electric machine MG are used as the driving force source for running.

By the way, at the synchronous timing of the clutch K0 at which the engine rotation speed Ne and the MG rotation speed Nmg are the same, if the actual pressure of the K0 oil pressure has not sufficiently decreased (that is, the clutch K0 has not been released), the engine 14 is transmitted to the rotor shaft 40 of the rotary electric machine MG via the clutch K0, the vehicle 10 may experience a starting shock that exceeds a predetermined allowable range. Note that "the clutch K0 is synchronized" means that the engine rotation speed Ne, which is the same value as the rotation speed of the engine connecting shaft 32 on one side of the power transmission path controlled by the clutch K0, and the MG rotation speed Nmg on the other side. , are the same. Synchronous timing is the point in time when the clutch K0 is synchronized.

The transmission torque capacity Tc of the clutch K0 changes as shown in FIG. 3 according to the actual pressure of the K0 oil pressure.

In the case 1 where the MG rotation speed Nmg is the lowest at the start of the start control of the engine 14, the clutch K0 is synchronized at the time x3a. At the synchronous timing, the MG rotation speed Nmg is the rotation speed value Nmg1 [rpm].

In the case 3 where the MG rotational speed Nmg is the highest at the start of the start control of the engine 14, the clutch K0 is synchronized at time x3c. At the synchronous timing, the MG rotation speed Nmg is the rotation speed value Nmg3 [rpm].

In case 2 where the MG rotation speed Nmg at the start of the start control of the engine 14 is between cases 1 and 3, the clutch K0 is synchronized at time x3b (x3a<x3b<x3c). At the synchronous timing, the MG rotation speed Nmg is the rotation speed value Nmg2 [rpm].

The higher the MG rotation speed Nmg at the synchronous timing, the longer the period required for the engine rotation speed Ne to rise to the same rotation speed as the MG rotation speed Nmg, that is, from the start of the start control of the engine 14 until the clutch K0 is synchronized. period becomes longer. Therefore, the higher the MG rotation speed Nmg at the synchronous timing, the lower the actual pressure of the K0 oil pressure that temporarily releases the clutch K0 at the synchronous timing, and the smaller the transmission torque capacity Tc at the synchronous timing. On the other hand, the lower the MG rotation speed Nmg at the synchronous timing, the less likely the actual pressure of the K0 oil pressure for temporarily disengaging the clutch K0 at the synchronous timing will become lower, and the more likely the transmission torque capacity Tc at the synchronous timing will increase.

Due to the synchronization of the clutch K0, the clutch K0 transmits the engine torque Te to the rotor shaft 40 of the rotary electric machine MG as a disturbance. When the transmission torque capacity Tc at the synchronous timing is large, the engine torque Te transmitted by the clutch K0 becomes large and the starting shock tends to fall outside the predetermined allowable range. The torque Te becomes small, and the starting shock tends to fall within a predetermined allowable range.

Here, when the MG rotational speed Nmg at the synchronous timing is the rotational speed value Nmg2 as in Case 2, it is assumed that the transmission torque capacity Tc of the clutch K0 at the synchronous timing is the upper limit value at which the start shock can be tolerated. In case 1, the starting shock associated with starting the engine 14 by the early ignition starting method is outside the predetermined allowable range. Therefore, in case 1, the push start control is suitable for executing start control of the engine 14 . In the case of case 3, the starting shock associated with starting the engine 14 by the early ignition starting method falls within a predetermined allowable range. Therefore, in the case of case 3, the early ignition starting method is suitable for the starting control of the engine 14 . That is, when the MG rotational speed Nmg at the synchronous timing is equal to or higher than the rotational speed value Nmg2, the starting shock caused by starting the engine 14 by the early ignition starting method falls within a predetermined allowable range, and the MG rotational speed Nmg at the synchronous timing is If the rotation speed value is less than Nmg2, the starting shock associated with starting the engine 14 by the early ignition starting method is outside the predetermined allowable range.

Returning to FIG. 1, the electronic control unit 80 includes a starting method setting unit 80a, a starting determining unit 80b, an assist torque determining unit 80c, a possible output torque calculating unit 80d, a required torque calculating unit 80e, a starting method determining unit 80f, and a starting control unit. It functionally includes a portion 80g.

The starting method setting unit 80 a sets the starting method of the engine 14 . Note that the starting method set by the starting method setting unit 80a is not necessarily executed.

For example, based on the current MG rotation speed Nmg, the system shaft torque Tsys, and the turbine rotation speed Nt, the starting method setting unit 80a determines the clutch K0 when it is assumed that the early ignition starting method is executed as the starting control of the engine 14. MG rotation speed Nmg at the synchronous timing is calculated (that is, predicted) as a synchronous vehicle state value. The “current” here means the point in time when the starting method of the engine 14 is set. The system shaft torque Tsys is an amount of driving torque required on the rotor shaft 40 for the driving force source (the engine 14 and the rotary electric machine MG) for driving the vehicle 10, and is an input torque input to the torque converter 16, for example. , which is the target value of the drive torque for traveling output to the drive wheels 34 (torque converter 16) by the engine 14 and the rotary electric machine MG shown in FIG. The system shaft torque Tsys corresponds to the "required torque" in the present invention. For example, the system shaft torque Tsys is obtained by calculating a target value of the output torque of the drive wheels 34 based on the accelerator opening θacc and the vehicle speed V, is obtained by converting the calculated target value into a torque on the rotor shaft 40 in consideration of the state of charge value SOC (in other words, the charge/discharge demand amount of the power storage device 54).

For example, the actual MG rotational speed Nmg, the system shaft torque Tsys, and the turbine rotational speed Nt at the time of setting the current starting method of the engine 14, the MG rotational speed (predicted value) Nmg at the synchronous timing of the clutch K0, MG rotation speed Nmg is calculated. Since the control of the K0 oil pressure from the start of the start control of the engine 14 to the synchronous 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, The MG rotation speed Nmg at the synchronous timing of the clutch K0 can be calculated based on the current MG rotation speed Nmg, the system shaft torque Tsys, and the turbine rotation speed Nt.

For example, the starting method setting unit 80a determines whether or not the MG rotation speed Nmg at the predicted synchronization timing is equal to or greater than a predetermined MG rotation speed determination value Nmg_jdg [rpm]. The predetermined MG rotation speed determination value Nmg_jdg is experimentally or designed in advance to determine that the starting shock is within a predetermined allowable range when the start control of the engine 14 is executed by the early ignition starting method. It is a defined judgment value. For example, it is the rotation speed value Nmg2 in FIG. 3 described above. When it is determined that the MG rotation speed Nmg at the predicted synchronization timing is equal to or higher than the predetermined MG rotation speed determination value Nmg_jdg, the starting method setting unit 80a sets the early ignition starting method as the starting method of the engine 14. When determining 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 setting unit 80a sets the push starting method as the starting method of the engine 14 .

Thus, the starting method setting unit 80a starts the engine 14 based on whether or not the starting shock that occurs when it is assumed that the early ignition starting method is executed as the starting control of the engine 14 is within a predetermined allowable range. The method is set at any time, for example, every predetermined period.

Further, the starting method setting unit 80a determines whether or not the starting method of the engine 14 has been switched from the early ignition starting method to the push starting method. Hereinafter, the time point at which the starting method setting unit 80a determines that the starting method of the engine 14 has been switched from the early ignition starting method to the push-start method will be referred to as a "switching time point".

In a state where the starting method set by the starting method setting unit 80a is the early ignition starting method, an assist for early ignition starting is provided from the MG torque Tmg in preparation for the case where start control of the engine 14 is executed by the early ignition starting method. The torque is secured as the secured torque for early ignition start, and the remainder is distributed as the distributed torque Tr for MG driving (see FIG. 5). The MG travel distribution torque Tr is a torque on the rotor shaft 40 that can be distributed as the travel drive torque portion of the MG torque Tmg, and is a travel torque that can be output to the drive wheels 34 (torque converter 16) by the rotary electric machine MG. is the driving torque for It should be noted that the MG drive distributed torque Tr corresponds to the "possible output torque" in the present invention. In a state where the starting method set by the starting method setting unit 80a is the push start method, an assist for push start is provided from the MG torque Tmg in preparation for the case where start control of the engine 14 is executed by the push start method. The torque is secured as a secured torque for push-starting, and the remainder is distributed as a distribution torque Tr for MG driving (see FIG. 5). By controlling the MG traveling distributed torque Tr to be larger than the system shaft torque Tsys, the driving force required of the vehicle 10 by the driver is satisfied, while the MG traveling distributed torque Tr is controlled to be greater than the system shaft torque Tsys. As the shaft torque Tsys becomes larger, the energy use efficiency (electricity cost) of the rotary electric machine MG deteriorates.

Since the engine torque Te is not used to start the engine 14 in the push-start method, the secure torque for push-start is larger than the secure torque for early ignition start. Therefore, immediately after the starting method set by the starting method setting unit 80a is switched from the early ignition starting method to the push start method, the assist torque is switched from the secured torque for early ignition start to the secured torque for push start. Of the torque Tmg, the distributed torque Tr for MG travel is rapidly reduced. If the start control of the engine 14 is executed by the push-start method at the timing when the MG traveling distributed torque Tr suddenly decreases, the MG traveling distributed torque Tr becomes insufficient with respect to the system shaft torque Tsys, and the engine starts. A pull-in shock may occur.

The start determination unit 80b determines whether or not start control of the engine 14 is to be executed. For example, when the vehicle state moves from the EV area to the EHV area in the EV/EHV area map shown in FIG. Further, when the start determination unit 80b determines to execute the start control of the engine 14, it determines whether or not the determination time is within a predetermined period T from the switching time. The predetermined period T is set so that the MG driving distributed torque Tr of the MG torque Tmg is required to have a required magnitude so that the pull-in shock at the time of starting the engine is within the allowable range even if the push-start is executed. It is a period necessary to increase the MG torque Tmg or change the gear ratio γ of the automatic transmission 18, which is predetermined experimentally or by design in advance. period.

When the start determination unit 80b determines that the start control of the engine 14 is to be executed and determines that the determination time is within the predetermined time period T from the switching time, the assist torque determination unit 80c selects the starting method. It is determined whether or not the assist torque of the clutch K0 has increased due to the switching of the starting method set by the setting section 80a. That is, it is determined whether or not the secured torque for push-starting has increased with respect to the secured torque for early ignition starting due to the switching of the starting method. If the assist torque has not increased, the MG traveling distributed torque Tr of the MG torque Tmg has not decreased.

When the start determination unit 80b determines that the start control of the engine 14 is to be executed and the determination time is within the predetermined period T from the switching time, the possible output torque calculation unit 80d determines that the engine MG travel distribution torque Tr of MG torque Tmg is calculated as output possible torque based on transmission torque capacity Tc of clutch K0 when it is assumed that the push-start method is executed as the start control of No. 14.

When the start determination unit 80b determines that the start control of the engine 14 is to be executed and the determination time is within the predetermined period T from the switching time, the required torque calculation unit 80e determines that the engine 14 The system shaft torque Tsys is calculated as the required torque based on the transmission torque capacity Tc of the clutch K0 when it is assumed that the early ignition start method is executed as the start control of .

The starting method determination unit 80f basically determines one of the early ignition starting method and the push starting method set by the starting method setting unit 80a as a method for executing start control of the engine 14. FIG. However, in the following two cases, the starting method determining unit 80f determines the early ignition starting method as the method for executing the starting control of the engine 14 regardless of the starting method set by the starting method setting unit 80a. In the first case, the assist torque determination unit 80c determines that the assist torque of the clutch K0 has not increased. In the second case, the MG traveling distributed torque Tr calculated by the output possible torque calculating section 80d is smaller than the system shaft torque Tsys calculated by the required torque calculating section 80e, that is, when the MG traveling distributed torque Tr This is the case where the shaft torque Tsys is insufficient. Thus, the determination of the method for executing the starting control of the engine 14 by the starting method determination unit 80f is more effective than the suppression of the occurrence of the starting shock when the engine start control is performed by the early ignition starting method. Emphasis is placed on suppressing the occurrence of a pull-in shock when engine start control is executed by the system. Even if the above two cases are applicable, for example, if the starting control of the engine 14 by the early ignition starting method is not possible due to the requirements of the engine 14 side, the starting method determination unit 80f selects the push starting method. is determined as the method for executing the starting control of the engine 14 .

When the starting method determining unit 80f determines the early ignition starting method as the method for executing the starting control of the engine 14, the starting control unit 80g executes the starting control of the engine 14 by the early ignition starting method. It should be noted that the transmission torque capacity Tc of the clutch K0 when the starting control of the engine 14 is executed by the early ignition starting method regardless of the starting method set by the starting method setting section 80a is that of the early ignition starting method. When the starting method determination unit 80f determines the push start method as the method for executing start control of the engine 14, the start control unit 80g executes the start control of the engine 14 by the push start method.

FIG. 4 is an example of a flow chart for explaining the essential part of the control operation of the electronic control unit 80 shown in FIG. For example, when it is determined that the engine 14 is to be started while the vehicle 10 is running on the motor, the flowchart of FIG. 4 is executed.

In step S10 corresponding to the function of the start determination unit 80b, start control of the engine 14 is executed within a predetermined time period T from the time when it is determined that the start method of the engine 14 has been switched from the early ignition start method to the push start method. It is determined whether or not it has been determined. If the determination in step S10 is affirmative, step S20 is executed. If the determination in step S10 is negative, step S70 is executed.

In step S20 corresponding to the function of the assist torque determining section 80c, it is determined whether or not the assist torque of the clutch K0 has increased due to the switching of the starting method. If the determination in step S20 is affirmative, step S30 is executed. If the determination in step S20 is negative, step S100 is executed.

In step S30 corresponding to the function of the possible output torque calculating unit 80d, the engine 14 is started by the push-start method, based on the transmission torque capacity Tc of the clutch K0. The MG traveling distributed torque Tr is calculated as the output possible torque. Then step S40 is executed.

In step S40 corresponding to the function of the required torque calculation unit 80e, the system shaft torque Tsys is calculated as the required torque based on the transmission torque capacity Tc of the clutch K0 when it is assumed that the early ignition start method is executed as the starting control of the engine 14. calculated as Then step S50 is executed.

At step S50 corresponding to the function of the starting method determination unit 80f, it is determined whether or not the MG driving distributed torque Tr calculated at step S30 is smaller than the system shaft torque Tsys calculated at step S40. If the determination in step S50 is affirmative, step S60 is executed. If the determination in step S50 is negative, step S100 is executed.

In step S60 corresponding to the function of the starting method determination unit 80f, it is determined whether or not the start control of the engine 14 by the early ignition starting method is possible. If the determination in step S60 is affirmative, step S80 is executed. If the determination in step S60 is negative, step S100 is executed.

In step S70 corresponding to the function of the start determination unit 80b, it is determined whether or not it is determined to execute the start control of the engine 14 within the period in which the start method of the engine 14 is the early ignition start method. If the determination in step S70 is affirmative, step S60 is executed. If the determination in step S70 is negative, step S100 is executed.

In step S80 corresponding to the function of the starting method determination unit 80f, the early ignition starting method is determined as the starting method of the engine 14 to be actually executed. Then step S90 is executed.

In step S90 corresponding to the function of the start control section 80g, start control of the engine 14 is executed by the early ignition start method. and return.

In step S100 corresponding to the function of the starting method determination unit 80f, the push starting method is determined as the starting method of the engine 14 to be actually executed. Then step S110 is executed.

In step S110 corresponding to the function of the start control section 80g, start control of the engine 14 is executed by the push start method. and return.

FIG. 5 is an example of a time chart explaining the control operation of the electronic control unit 80 shown in FIG. The horizontal axis of FIG. 5 is time t [sec].

Before time t0, the vehicle 10 is running on the motor, and the running road is an uphill road. For example, as the driver further depresses the accelerator pedal, the accelerator opening degree θacc gradually increases, and the drive demand amount for the vehicle 10 gradually increases. On the other hand, the MG rotation speed Nmg of the rotary electric machine MG, which is the driving force source for running, gradually decreases due to running on the uphill road.

The starting method of the engine 14 is set to either an early ignition starting method or a push starting method at each time. For example, the starting method of the engine 14 is determined based on whether or not the starting shock that occurs when it is assumed that the early ignition starting method is executed as the starting control of the engine 14 is within a predetermined allowable range. At time t0, the starting method of the engine 14 is switched from the early ignition starting method to the push starting method. At time t1 (>t0), it is decided to execute start control of the engine 14 . This time t1 is between time t0 and time t3 after a predetermined period T has elapsed from time t0. At time t1, start control of the engine 14 is started (cranking by the rotary electric machine MG is started), and at time t4, the start control of the engine 14 is completed, and the vehicle 10 is switched to hybrid running. Whether the start control of the engine 14 is executed by the early ignition start method or the push start method will be described later. It should be noted that the initial stages of both the early ignition starting method and the push starting method are common in that the clutch K0 is engaged and cranking is performed by the rotary electric machine MG. Further, since it takes time for the actual pressure of the K0 hydraulic pressure that engages the clutch K0 to rise for this cranking, it takes time from the start of the engine start control until the engine rotation speed Ne starts to rise. requires. The period between the time t1 and the time t4 is the period during which the start control of the engine 14 is executed.

In FIG. 5, the MG driving distributed torque Tr calculated at each time is indicated by a dashed line. The MG travel distributed torque Tr is the remainder of the MG torque Tmg minus the assist torque for starting the engine. Before the time t0, the MG traveling distributed torque Tr secures the assist torque for starting the engine (secure torque for early ignition starting) when it is assumed that the early ignition starting method is executed as the starting control of the engine 14. calculated. That is, the MG driving distributed torque Tr is calculated based on the transmission torque capacity Tc of the clutch K0 when it is assumed that the engine start control is executed by the early ignition start method. After the time t0, the MG traveling distributed torque Tr secures the assist torque for starting the engine (assured torque for pushing start) when it is assumed that the push start method is executed as the start control of the engine 14. calculated. That is, the MG traveling distributed torque Tr is calculated based on the transmission torque capacity Tc of the clutch K0 when it is assumed that the engine start control is executed by the push start method.

In FIG. 5, two cases of the system shaft torque Tsys at each time are indicated by the one-dot chain line and two-dot chain line arrows, respectively. The system shaft torque Tsys after time t1 is a predicted value calculated based on the transmission torque capacity Tc of the clutch K0 when it is assumed that the early ignition starting method is started as the starting control of the engine 14 at time t1. .

When the system shaft torque Tsys changes as indicated by the dashed-dotted arrow, it is predicted that the MG driving distributed torque Tr will be smaller than the system shaft torque Tsys during the execution period of the engine start control. If the control is executed by the push-start method, there is a risk that a pull-in shock will occur when the engine is started. Therefore, in such a case, the start control of the engine 14 is performed by the early ignition start method instead of the push start method. It should be noted that the engine start control to be executed is switched from the push start method to the early ignition start method at time t2, which is delayed by the time required for calculation by the electronic control unit 80 from time t1. This time is earlier than the time at which the pull-in shock occurs when the cliff start method is executed. As a result, an increase in the starting torque (assist torque) is suppressed, the MG driving distributed torque Tr is secured, and the occurrence of a pull-in shock at the time of starting the engine is suppressed.

If the system shaft torque Tsys changes as indicated by the two-dot chain line arrow, it is predicted that the MG driving distributed torque Tr will not become smaller than the system shaft torque Tsys during the execution period of the engine start control. , there is no possibility of occurrence of a pull-in shock when the engine is started even if the start control of the engine 14 is executed by the push start method. Therefore, in such a case, the start control of the engine 14 is performed by the push start method. That is, the engine start control executed from time t1 is executed by the push start method after time t2.

In the case where the engine 14 is started at time t3 after a predetermined period T has elapsed from time t0 immediately after the start method is switched from the early ignition start method to the push start method, the engine 14 is started during the execution period of the engine start control. When the distributed torque Tr is predicted to be smaller than the system shaft torque Tsys, the starting control to be executed is the early ignition starting method before time t3, and the push starting method after time t3, as indicated by the dashed line. It is said that Further, when the engine 14 is started at time t0 immediately after the start method is switched from the early ignition start method to the push start method, the MG driving distributed torque Tr is greater than the system shaft torque Tsys during the execution period of the engine start control. is not predicted to decrease, the starting control to be executed is the early ignition starting method before time t0, and the push starting method after time t0, as indicated by the chain double-dashed line.

According to this embodiment, when the engine 14 is started within a predetermined time period T from the time when it is determined that the starting method of the engine 14 has been switched from the early ignition starting method to the push starting method, (a) pushing Based on the transmission torque capacity Tc of the clutch K0 when it is assumed that the start control of the engine 14 is executed by the starting method, the MG travel distribution torque Tr, which is the travel drive torque portion of the MG torque Tmg, is the torque that can be output. (b) the system shaft torque Tsys is calculated as the required torque based on the transmission torque capacity Tc of the clutch K0 when it is assumed that the start control of the engine 14 is executed by the early ignition start method, and (c) When the possible output torque is insufficient for the required torque, start control of the engine 14 is executed by the early ignition start method. In this way, when the engine 14 is started within a predetermined period T after it is determined that the starting method of the engine 14 has been switched from the early ignition starting method to the push starting method, the engine is actually started using the push starting method. When the start control of 14 is executed, if the MG driving distribution torque Tr is insufficient for the system shaft torque Tsys and a pull-in shock occurs at the time of engine start, an early start regardless of the starting method determined to be switched. Startup control of the engine 14 is executed by the ignition start method. This suppresses the occurrence of a pull-in shock when the engine is started.

Although the embodiments of the present invention have been described in detail above with reference to the drawings, the present invention is also applicable to other aspects.

In the above-described embodiment, the electronic control unit 80 functionally includes the assist torque determination unit 80c, but it does not necessarily have to include the assist torque determination unit 80c. In the control operation of the electronic control unit 80 that does not include the assist torque determining section 80c, for example, step S20 is omitted from the flowchart of FIG.

In the above-described embodiment, the system shaft torque Tsys (required torque) and the MG traveling distributed torque (output possible torque) were calculated as torque on the rotor shaft 40, but the transmission output shaft 24 is not limited to this. Alternatively, it may be calculated as torque on the top or the transmission input shaft 36 . In such a mode, if the possible output torque is insufficient with respect to the required torque, that is, if the possible output torque converted to the same shaft is smaller than the required torque, regardless of the starting method determined to have switched, the early Startup control of the engine 14 is executed by the ignition start method.

In the above-described embodiment, the setting of the starting method of the engine 14 by the starting method setting unit 80a is based on whether the starting shock is within a predetermined allowable range when it is assumed that the early ignition starting method is executed as the starting control of the engine 14. Although it was performed based on whether or not, it is not limited to this aspect. For example, when the state-of-charge value SOC of the power storage device 54 is equal to or greater than a predetermined value, the starting method setting unit 80a sets the push-start method in which the assist torque is relatively large as the starting method of the engine 14. If it is less than a predetermined value, an early ignition starting method in which the assist torque is relatively small may be set as the starting method of the engine 14 .

It should be noted that what has been described above is merely an embodiment of the present invention, and the present invention can be implemented in a mode with various modifications and improvements based on the knowledge of those skilled in the art without departing from the scope of the invention.

10: Vehicle 14: Engine (driving power source for traveling)
80: Electronic control device (control device)
K0: Clutch MG: Rotating electric machine (driving power source for running)
T: Predetermined period Tc: Transmission torque capacity Tmg: MG torque (output torque of rotary electric machine)
Tr: Distributed torque for MG driving (driving torque for driving out of output torque of rotary electric machine, torque that can be output)
Tsys: System shaft torque (required amount of drive torque for travel for the drive power source for travel, required torque)

Claims (1)

A control device for a vehicle comprising an engine and a rotating electrical machine as a driving force source for running, and a clutch for connecting and disconnecting a power transmission path between the engine and the rotating electrical machine,
When starting the engine within a predetermined period after it is determined that the starting method of the engine has been switched from the early ignition starting method to the push starting method,
Based on the transmission torque capacity of the clutch when it is assumed that the start control of the engine is executed by the push-start method, the drive torque for traveling out of the output torque of the rotating electric machine is calculated as the output possible torque. and calculating, as a demanded torque, a required amount of driving torque for running of the driving force source based on the transmission torque capacity of the clutch when it is assumed that the engine start control is executed by the early ignition starting method. 2. A control device for a vehicle, wherein when the possible output torque is insufficient with respect to the required torque, the start control of the engine is executed by the early ignition starting method.

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