JP7600828B2 - Vehicle control device - Google Patents

Description

The present invention relates to a control device for a vehicle that has an engine and an electric motor as driving power sources.

Vehicle control devices equipped with a driving force source including an engine and an electric motor, and a power transmission device that transmits the output torque of the driving force source to the drive wheels are well known. For example, there is a motor control device for a hybrid vehicle described in Patent Document 1. Patent Document 1 discloses that when changing the driving torque from negative to positive, in order to suppress the so-called tip-in shock, which is a backlash-reducing shock that occurs due to teeth striking caused by the direction in which backlash between rotating members in the power transmission device, such as gear backlash, is eliminated, being reversed, the driving torque is changed from negative to positive by a backlash-reducing torque generated by the output torque of the electric motor.

JP 2015-89735 A

The technology described in Patent Document 1 is for controlling backlash-reducing torque when the engine is stopped, and it is assumed that backlash-reducing torque is realized by the engine output torque and the electric motor output torque while the engine is running. Also, to achieve backlash-reducing torque that suppresses tip-in shock, highly accurate torque control is required. However, when trying to achieve the target torque for suppressing tip-in shock by combining the engine output torque and the electric motor output torque, there is a risk that the torque control during backlash-reducing cannot be performed with high accuracy due to deviations in command torque caused by differences in communication delays between the two and differences in torque accuracy caused by differences in response delays between the actuators.

The present invention was made against the background of the above circumstances, and its purpose is to provide a vehicle control device that can appropriately suppress tip-in shock when two driving power sources, an engine and an electric motor, are available.

The gist of a first invention is (a) a control device for a vehicle including a driving force source including an engine and an electric motor, and a power transmission device that transmits an output torque of the driving force source to driving wheels, (b) including a driving force source control unit that controls the engine and the electric motor so that, within a predetermined torque range of the output torque of the driving force source where a backlash-eliminating direction in the power transmission device is reversed when the driving torque is changed from negative torque to positive torque, the output torque of the driving force source becomes a slowly changing torque having a smaller increasing gradient than outside the predetermined torque range, (c) the driving force source control unit controls the output torque of the engine while keeping the output torque of the electric motor fixed so as to realize the slowly changing torque , and (d) the driving force source control unit controls the output torque of the engine while keeping the output torque of the electric motor fixed so as to realize the slowly changing torque, The driving force source control unit, during execution of slow-change control to realize the slow-change torque, sets an intake required torque, which is a required value of the output torque of the engine controlled by adjusting the intake air amount of the engine, which is higher by a predetermined torque than the slow-change torque, and controls the output torque of the engine by setting a post-retard required torque, which is a required value of the output torque of the engine after the intake required torque is reduced by ignition retard control, to the slow-change torque, and fixes the output torque of the electric motor by setting a required electric motor torque, which is a required value of the output torque of the electric motor, to zero, (e) the predetermined torque amount is a predetermined torque amount that enables the slow-change torque to be formed by the ignition retard control .

In addition, a second invention is a vehicle control device described in the first invention, in which, when the post-retard required torque exceeds an upper limit torque of the specified torque region, the driving force source control unit gradually reduces the amount of torque reduction due to the ignition retard control in the post-retard required torque, and prepares to end the ignition retard control .

Further, a third invention is a control device for a vehicle described in the first or second invention, when there is a request to charge a power storage device that charges with electricity from the electric motor generated by the power of the engine, during execution of the slow-change control, the driving force source control unit sets the intake required torque to be higher by a predetermined torque than a torque value obtained by adding a charging required torque, which is a required value of the output torque of the engine that realizes the charging request, to the slow-change torque, and controls the output torque of the engine by setting the post-retard required torque to a torque value obtained by adding the charging required torque to the slow-change torque, and keeps the output torque of the electric motor fixed by setting the required electric motor torque to the charging required torque instead of setting it to zero .

The fourth invention is a vehicle control device according to the third invention, in which the driving force source control unit maintains the charging torque requirement at the value at the start of the slow-change control while the slow-change control is being executed.

Further, a fifth invention is a vehicle control device as described in the first or second invention, wherein when the post-retard required torque cannot be realized in the ignition retard control, instead of keeping the output torque of the electric motor in a fixed state, the driving force source control unit controls the output torque of the electric motor so as to compensate for the torque difference between the post-retard required torque and the output torque of the engine after the ignition retard control.

According to the first invention, within a predetermined torque range of the output torque of the driving force source where the direction of backlash elimination in the power transmission device is reversed when the driving torque is changed from negative torque to positive torque, the engine and the electric motor are controlled so that the output torque of the driving force source is a slowly changing torque with a smaller rising gradient than outside the predetermined torque range, making it easier to suppress tip-in shock when the vehicle is switched from a driven state to a driving state. Furthermore, since the output torque of the engine is controlled with the output torque of the electric motor fixed so as to realize a slowly changing torque within the predetermined torque range, within the predetermined torque range, the output torque of the driving force source is precisely controlled to a slowly changing torque solely by changes in the output torque of the engine. Therefore, when two driving force sources, the engine and the electric motor, can be used, tip-in shock can be appropriately suppressed.

In addition, according to the first invention, during execution of slow-change control to realize a slow-change torque, an intake required torque is set that is higher than the slow-change torque by a predetermined torque, and the post-retard required torque after being reduced by ignition retard control is set to the slow-change torque, thereby controlling the output torque of the engine, and the required motor torque is set to zero, thereby fixing the output torque of the motor.Therefore, within the predetermined torque region, the output torque of the driving force source is appropriately and accurately controlled to the slow-change torque solely by changes in the output torque of the engine.

In addition, according to the third invention, when there is a request to charge the power storage device, during execution of the slow-change control, an intake request torque is set that is higher by a predetermined torque than the torque value obtained by adding the charging request torque to the slow-change torque, and the post-retard request torque is set to a torque value obtained by adding the charging request torque to the slow-change torque, thereby controlling the output torque of the engine, and the required motor torque is set to the charging request torque, thereby fixing the output torque of the motor. Therefore, while the charging request for the power storage device is realized, within the predetermined torque range, the output torque of the driving force source is precisely controlled to the slow-change torque mainly by changes in the engine output torque.

In addition, according to the fourth invention, while the slow-change control is being executed, the charging request torque is held at the value at the start of the slow-change control, so that even if the charging request of the storage device fluctuates while the slow-change control is being executed, the output torque of the driving force source is accurately controlled to the slow-change torque.

In addition, according to the fifth invention, when the post-retard required torque cannot be realized in the ignition retard control, the output torque of the electric motor is controlled to compensate for the torque difference between the post-retard required torque and the engine output torque after the ignition retard control, so that the output torque of the driving force source is more accurately controlled to a slowly changing torque within a specified torque range.

1 is a diagram illustrating a schematic configuration of a vehicle to which the present invention is applied, and is also a diagram illustrating main parts of control functions and a control system for various controls in the vehicle. 11A and 11B are diagrams illustrating how gentle-change control is performed with high accuracy. 10A and 10B are diagrams for explaining how gentle-change control is accurately executed when there is a request to charge the battery. 1 is a flowchart illustrating the main control operations of an electronic control device, and is a flowchart illustrating the control operations for appropriately suppressing tip-in shock when two driving power sources, an engine and an electric motor, are available.

The following describes in detail an embodiment of the present invention with reference to the drawings.

Figure 1 is a diagram illustrating the general configuration of a vehicle 10 to which the present invention is applied, as well as a diagram illustrating the main parts of the control functions and control system for various controls in the vehicle 10. In Figure 1, the vehicle 10 is a hybrid vehicle equipped with an engine 12 and an electric motor MG, which are a driving force source SP for running. The vehicle 10 also has driving wheels 14 and a power transmission device 16 provided in the power transmission path between the engine 12 and the driving wheels 14.

The engine 12 is a known internal combustion engine such as a gasoline engine or a diesel engine. The engine 12 has an engine control device 50, which includes a throttle actuator, a fuel injection device, an ignition device, and the like, provided on the vehicle 10, controlled by an electronic control device 90 (described later), thereby controlling the engine torque Te, which is the output torque of the engine 12.

The electric motor MG is a rotating electric machine that functions as a motor to generate mechanical power from electric power and as a generator to generate electric power from mechanical power, and is a so-called motor generator. The electric motor MG is connected to a battery 54 provided in the vehicle 10 via an inverter 52 provided in the vehicle 10. The battery 54 is an electricity storage device that supplies and receives electric power to the electric motor MG. The electric motor MG controls the MG torque Tm, which is the output torque of the electric motor MG, by controlling the inverter 52 by an electronic control device 90 described later. For example, when the rotation direction of the electric motor MG is the same as that of the engine 12 during operation, the MG torque Tm is a power torque at the positive torque on the acceleration side, and a regenerative torque at the negative torque on the deceleration side. The electric motor MG generates electric power, for example, by the power of the engine 12, and the battery 54 charges the electric power from the electric motor MG. The electric power also means electric energy when there is no particular distinction. The above power also refers to torque and force unless otherwise specified.

The power transmission device 16 includes a K0 clutch 20, a torque converter 22, an automatic transmission 24, and the like, in a case 18, which is a non-rotating member attached to the vehicle body. The K0 clutch 20 is a clutch provided between the engine 12 and the electric motor MG in the power transmission path between the engine 12 and the drive wheels 14. The torque converter 22 is connected to the engine 12 via the K0 clutch 20. The automatic transmission 24 is connected to the torque converter 22 and is interposed in the power transmission path between the torque converter 22 and the drive wheels 14. The power transmission device 16 also includes a propeller shaft 28 connected to a transmission output shaft 26, which is an output rotating member of the automatic transmission 24, a differential gear 30 connected to the propeller shaft 28, a pair of drive shafts 32 connected to the differential gear 30, and the like. The power transmission device 16 also includes an engine connecting shaft 34 that connects the engine 12 and the K0 clutch 20, and an electric motor connecting shaft 36 that connects the K0 clutch 20 and the torque converter 22.

The electric motor MG is connected to the electric motor connecting shaft 36 inside the case 18 so that the power can be transmitted. In other words, the electric motor MG is connected to the power transmission path between the K0 clutch 20 and the torque converter 22 so that the power can be transmitted. In other words, the electric motor MG is connected to the torque converter 22 and the automatic transmission 24 so that the power can be transmitted without going through the K0 clutch 20.

The torque converter 22 includes a pump wheel 22a connected to the motor connecting shaft 36, and a turbine wheel 22b connected to the transmission input shaft 38, which is an input rotating member of the automatic transmission 24. The torque converter 22 is a fluid-type power transmission device that transmits driving force from the driving force source SP from the motor connecting shaft 36 to the transmission input shaft 38 via fluid. The torque converter 22 includes an LU clutch 40 as a direct-coupled clutch that connects the pump wheel 22a and the turbine wheel 22b, that is, that connects the motor connecting shaft 36 and the transmission input shaft 38. The LU clutch 40 is a known lock-up clutch.

The automatic transmission 24 is a known planetary gear type automatic transmission that includes, for example, one or more planetary gear devices (not shown) and multiple engagement devices CB. The engagement devices CB are, for example, known hydraulic friction engagement devices. The engagement devices CB have their respective torque capacities, or CB torque Tcb, changed by the CB hydraulic pressure PRcb, which is a regulated hydraulic pressure supplied from the hydraulic control circuit 56, thereby switching between operating states, or control states, such as an engaged state or a disengaged state.

The automatic transmission 24 is a stepped transmission in which one of a plurality of gear stages (also called gear stages) with different speed ratios (also called gear ratios) γat (=AT input rotation speed Ni/AT output rotation speed No) is formed by engaging one of the engagement devices CB. The automatic transmission 24 switches between gear stages formed according to the driver's accelerator operation, vehicle speed V, etc. by an electronic control device 90 described later. The AT input rotation speed Ni is the rotation speed of the transmission input shaft 38, and is the input rotation speed of the automatic transmission 24. The AT input rotation speed Ni is the same value as the turbine rotation speed Nt, which is the output rotation speed of the torque converter 22. The AT input rotation speed Ni can be expressed as the turbine rotation speed Nt. The AT output rotation speed No is the rotation speed of the transmission output shaft 26, and is the output rotation speed of the automatic transmission 24.

The K0 clutch 20 is a hydraulic friction engagement device that is composed of, for example, a multi-plate or single-plate clutch. The K0 clutch 20 switches between control states such as an engaged state and a released state by changing the torque capacity of the K0 clutch 20, K0 torque Tk0, using the regulated hydraulic pressure, K0 hydraulic pressure PRk0, supplied from the hydraulic control circuit 56.

In the vehicle 10, when the K0 clutch 20 is engaged, the engine 12 and the torque converter 22 are connected so that power can be transmitted. On the other hand, when the K0 clutch 20 is disengaged, power transmission between the engine 12 and the torque converter 22 is interrupted. Since the electric motor MG is connected to the torque converter 22, the K0 clutch 20 functions as a clutch that connects and disconnects the engine 12 from the electric motor MG.

In the power transmission device 16, when the K0 clutch 20 is engaged, the power output from the engine 12 is transmitted from the engine connecting shaft 34 to the drive wheels 14 via the K0 clutch 20, the electric motor connecting shaft 36, the torque converter 22, the automatic transmission 24, the propeller shaft 28, the differential gear 30, the drive shaft 32, etc. in that order. In addition, regardless of the control state of the K0 clutch 20, the power output from the electric motor MG is transmitted from the electric motor connecting shaft 36 to the drive wheels 14 via the torque converter 22, the automatic transmission 24, the propeller shaft 28, the differential gear 30, the drive shaft 32, etc. in that order. In this way, the power transmission device 16 transmits the drive source torque Tsp, which is the output torque of the drive source SP, to the drive wheels 14. The drive source torque Tsp is the total torque of the engine torque Te and the MG torque Tm.

The vehicle 10 is equipped with a MOP 58, which is a mechanical oil pump, an EOP 60, which is an electric oil pump, a pump motor 62, and the like. The MOP 58 is connected to the pump impeller 22a, and is rotated and driven by a driving force source SP to discharge hydraulic oil OIL used in the power transmission device 16. The pump motor 62 is a motor dedicated to the EOP 60 for rotating and driving the EOP 60. The EOP 60 is rotated and driven by the pump motor 62 to discharge hydraulic oil OIL. The hydraulic oil OIL discharged by the MOP 58 and EOP 60 is supplied to the hydraulic control circuit 56. The hydraulic control circuit 56 supplies the CB hydraulic pressure PRcb, the K0 hydraulic pressure PRk0, and the like, which are adjusted based on the hydraulic oil OIL discharged by the MOP 58 and/or the EOP 60.

The vehicle 10 further includes an electronic control device 90 that includes a control device for the vehicle 10. The electronic control device 90 includes a so-called microcomputer that includes, for example, a CPU, RAM, ROM, an input/output interface, and the like, and the CPU executes various controls of 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. The electronic control device 90 includes computers for engine control, electric motor control, hydraulic control, etc., as necessary.

The electronic control device 90 receives various signals based on detection values from various sensors provided in the vehicle 10 (e.g., engine rotation speed sensor 70, turbine rotation speed sensor 72, output rotation speed sensor 74, MG rotation speed sensor 76, accelerator opening sensor 78, throttle valve opening sensor 80, air flow meter 82, brake switch 84, battery sensor 86, oil temperature sensor 88, etc.) (e.g., engine rotation speed Ne, which is the rotation speed of the engine 12, turbine rotation speed Nt, which is the same value as AT input rotation speed Ni, AT output rotation speed No, which corresponds to the vehicle speed V, rotation speed of the electric motor MG, etc.). The following signals are supplied: MG rotation speed Nm, which is the rotation speed; accelerator opening θacc, which is the amount of accelerator operation by the driver that indicates the magnitude of the driver's acceleration operation; throttle valve opening θth, which is the opening of the electronic throttle valve; intake air amount Qair of the engine 12; brake-on signal Bon, which is a signal indicating that the brake pedal for operating the wheel brakes is being operated by the driver; battery temperature THbat, battery charge/discharge current Ibat, battery voltage Vbat of the battery 54; hydraulic oil temperature THoil, which is the temperature of the hydraulic oil OIL in the hydraulic control circuit 56, etc.

The electronic control device 90 outputs various command signals (e.g., engine control command signal Se for controlling the engine 12, MG control command signal Sm for controlling the electric motor MG, CB hydraulic control command signal Scb for controlling the engagement device CB, K0 hydraulic control command signal Sk0 for controlling the K0 clutch 20, LU hydraulic control command signal Slu for controlling the LU clutch 40, EOP control command signal Seop for controlling the EOP 60, etc.) to each device (e.g., engine control device 50, inverter 52, hydraulic control circuit 56, pump motor 62, etc.) provided in the vehicle 10.

The electronic control device 90 is equipped with a driving force source control means, i.e., a driving force source control unit 92, and a gear shift control means, i.e., a gear shift control unit 94, in order to realize various controls in the vehicle 10.

The drive power source control unit 92 includes a function as an engine control means, i.e., an engine control unit 92a, that controls the operation of the engine 12, and a function as an electric motor control means, i.e., an electric motor control unit 92b, that controls the operation of the electric motor MG via the inverter 52, and is a hybrid control means, i.e., a hybrid control unit, that performs hybrid drive control by the engine 12 and the electric motor MG through these control functions.

The driving force source control unit 92 calculates the driving demand amount of the vehicle 10 by the driver, for example, by applying the accelerator opening θacc and the vehicle speed V to a driving demand amount map. The driving demand amount map is a relationship that is experimentally or design-wise determined and stored in advance, i.e., a predetermined relationship. The driving demand amount is, for example, the required driving torque Trdem at the driving wheels 14. In other words, the required driving torque Trdem [Nm] is the required driving power Prdem [W] at the vehicle speed V at that time. The driving demand amount can also be the required driving force Frdem [N] at the driving wheels 14, the required AT output torque at the transmission output shaft 26, etc. In calculating the driving demand amount, the AT output rotation speed No, etc. may be used instead of the vehicle speed V.

The driving force source control unit 92 outputs an engine control command signal Se for controlling the engine 12 and an MG control command signal Sm for controlling the electric motor MG so as to realize the required driving power Prdem, taking into consideration the transmission loss, the auxiliary load, the gear ratio γat of the automatic transmission 24, the chargeable power Win and dischargeable power Wout of the battery 54, etc. The engine control command signal Se is, for example, a command value for the engine power Pe, which is the power of the engine 12 that outputs the engine torque Te at the current engine rotation speed Ne. The MG control command signal Sm is, for example, a command value for the power consumption Wm of the electric motor MG that outputs the MG torque Tm at the current MG rotation speed Nm.

The chargeable power Win of the battery 54 is the maximum power that can be input, which specifies the limit on the input power of the battery 54, and indicates the input limit of the battery 54. The dischargeable power Wout of the battery 54 is the maximum power that can be output, which specifies the limit on the output power of the battery 54, and indicates the output limit of the battery 54. The chargeable power Win and dischargeable power Wout of the battery 54 are calculated by the electronic control unit 90, for example, based on the battery temperature THbat and the battery charge amount SOC. The battery charge amount SOC is the charge state value [%] of the battery 54 that indicates the charge state corresponding to the charge amount of the battery 54, and is calculated by the electronic control unit 90, for example, based on the battery charge/discharge current Ibat and the battery voltage Vbat.

When the required drive torque Trdem can be met only by the output of the electric motor MG, the drive power source control unit 92 sets the drive mode to motor drive (=EV drive) mode. In the EV drive mode, the drive power source control unit 92 performs EV drive by outputting drive force only from the electric motor MG of the drive power source SP when the K0 clutch 20 is in the disengaged state. On the other hand, when the required drive torque Trdem cannot be met without using at least the output of the engine 12, the drive power source control unit 92 sets the drive mode to engine drive mode, i.e., hybrid drive (=HV drive) mode. In the HV drive mode, the drive power source control unit 92 performs engine drive, i.e., HV drive by outputting drive force from at least the engine 12 of the drive power source SP when the K0 clutch 20 is in the engaged state. On the other hand, even if the required driving torque Trdem can be satisfied only by the output of the electric motor MG, the driving force source control unit 92 establishes the HV driving mode when the battery charge amount SOC is less than the engine start threshold SOCest or when the engine 12 or the like needs to be warmed up. The engine start threshold SOCest is a predetermined threshold for determining that the battery charge amount SOC is at a level at which the engine 12 needs to be forcibly started to charge the battery 54.

The shift control unit 94 uses, for example, a shift map, which is a predetermined relationship, to determine whether to shift the automatic transmission 24, and outputs a CB hydraulic control command signal Scb to the hydraulic control circuit 56 to execute shift control of the automatic transmission 24 as necessary. The shift map is a predetermined relationship having a shift line for determining whether to shift the automatic transmission 24 on a two-dimensional coordinate system with, for example, vehicle speed V and required driving torque Trdem as variables. In the shift map, the AT output rotation speed No may be used instead of the vehicle speed V, and the required driving force Frdem, accelerator opening θacc, throttle valve opening θth, etc. may be used instead of the required driving torque Trdem.

Here, when the required driving torque Trdem is increased, the driving torque Tr may be switched from a negative torque that puts the vehicle 10 in a driven state to a positive torque that puts the vehicle 10 in a driving state. In this case, the direction in which the backlash between the components constituting the power transmission device 16 is eliminated is reversed, and if the backlash is eliminated suddenly, a tip-in shock due to the backlash may occur. The driving state of the vehicle 10 is a state in which the driving wheels 14 are rotated by the torque output from the driving force source SP. The driven state of the vehicle 10 is a state in which the rotating members of the power transmission device 16 are rotated by the torque input from the driving wheels 14. The driving force source control unit 92 has a control function that suppresses the tip-in shock by suppressing the sudden backlash elimination when the direction in which the backlash is eliminated is reversed.

Specifically, when the required driving torque Trdem is increased from negative torque to positive torque, the driving force source control unit 92 controls the engine 12 and the electric motor MG so that within the clearance elimination torque region SPsl, the driving force source torque Tsp is set to a slowly changing torque Tspsl having a smaller rising gradient than that outside the clearance elimination torque region SPsl. The clearance elimination torque region SPsl is a predetermined torque region of the driving force source torque Tsp in which the clearance elimination direction in the power transmission device 16 is reversed when the driving torque Tr is changed from negative torque to positive torque. In other words, the clearance elimination torque region SPsl is a predetermined torque region of the driving force source torque Tsp that realizes a clearance point where the actual driving torque Tr becomes zero and a region of the driving torque Tr near the clearance point. In this embodiment, the torque region in which the clearance elimination direction in the power transmission device 16 is reversed is set by the driving force source torque Tsp rather than the driving torque Tr. The driving force source torque Tsp is the torque on the motor connecting shaft 36 or the transmission input shaft 38 for realizing the driving torque Tr. The slowly changing torque Tspsl is a predetermined increasing gradient of the driving force source torque Tsp for suppressing abrupt backlash elimination when the direction in which backlash is eliminated is reversed. The increasing gradient of the driving force source torque Tsp outside the backlash elimination torque region SPsl is set by a predetermined upper limit value, for example, when rising toward the driving force source torque Tsp for realizing the final torque of the required driving torque Trdem or when approaching the driving force source torque Tsp for realizing the final torque.

In order to achieve backlash elimination with suppressed tip-in shock, it is necessary to control the slow-changing torque Tspsl with high accuracy within the backlash elimination torque region SPsl. However, when trying to achieve the target slow-changing torque Tspsl by combining the engine torque Te and the MG torque Tm as the driving force source torque Tsp, there is a risk that the slow-changing torque Tspsl cannot be controlled with high accuracy due to differences in communication delays between the engine control command signal Se and the MG control command signal Sm and differences in response delays between the engine control device 50 and the inverter 52. For example, during the rising transition of the engine torque Te, the estimation accuracy of the engine torque Te is poor due to the response delay, and the estimated value of the engine torque Te is set higher than the actual value of the engine torque Te, while the required value of the MG torque Tm has a relatively high realization accuracy. Therefore, if the required value of the MG torque Tm is set based on the target value of the driving force source torque Tsp and the estimated value of the engine torque Te, the required value of the MG torque Tm becomes a negative torque, and the actual driving force source torque Tsp may fluctuate toward the negative torque side.

Therefore, the driving force source control unit 92 controls the engine torque Te while keeping the MG torque Tm fixed so as to realize the slowly changing torque Tspsl.

Figure 2 is a diagram explaining the accurate execution of the slow-change control CTspsl that realizes the slow-change torque Tspsl. In Figure 2, time t1a indicates the time when the static target driving force source torque Tspts shown by the two-dot chain line Aa is changed from negative torque to positive torque by the accelerator operation by the driver when the vehicle 10 is in a driven state. The static target driving force source torque Tspts is set as a target value of the driving force source torque Tsp to realize the final reaching torque of the requested driving torque Trdem by the driver. In addition, a dynamic target driving force source torque Tsptd shown by the thick solid line Ba is set for the static target driving force source torque Tspts. The dynamic target driving force source torque Tsptd is a target value of the driving force source torque Tsp that is set, for example, by a first-order delay function in the step response to the static target driving force source torque Tspts. However, the dynamic target driving force source torque Tsptd is set to a slowly changing torque Tspsl within the backlash eliminating torque region SPsl, which is indicated by the region between the lower limit torque Tllim and the upper limit torque Tulim (see time t2a-time t3a). The period during which the slowly changing torque Tspsl is set is the net backlash eliminating period during which the backlash eliminating direction in the power transmission device 16 is reversed. This net backlash eliminating period is the time during which the dynamic target driving force source torque Tsptd stays in the backlash eliminating torque region SPsl. Note that, since torque transmission in the power transmission device 16 requires a torque sufficient to overcome the loss and friction of each gear, the backlash eliminating torque region SPsl is set on the positive side of the zero point.

In Figure 2, the intake demand torque Tebs shown by the solid line Ca is set to realize the dynamic target driving force source torque Tsptd by, for example, the engine torque Te by controlling the throttle valve opening θth. The intake demand torque Tebs is a demand value of the engine torque Te controlled, for example, by adjusting the intake air amount Qair of the engine 12, and it is sufficient to set a rough torque for forming the slow-changing torque Tspsl. Specifically, if the intake required torque Tebs is too large, the number of situations where the slow-changing torque Tspsl cannot be formed by the ignition retard control CTsd of the engine 12 increases, while if the intake required torque Tebs is too small, there is a risk that the slow-changing torque Tspsl cannot be formed. Therefore, the intake required torque Tebs is set to a target torque higher than the slow-changing torque Tspsl by a predetermined torque Tspf, and is set to a value such that the actual engine torque Teact, which is the actual engine torque Te when the ignition retard control CTsd shown by the solid line Da is not performed, does not deviate significantly from the dynamic target driving force source torque Tsptd in the backlash-eliminating torque region SPsl. The predetermined torque Tspf is a torque value that is determined in advance so that the slow-changing torque Tspsl can be formed by the ignition retard control CTsd, for example. The ignition retard control CTsd of the engine 12 is one of the torque-down controls that reduces the engine torque Te by retarding the ignition timing of the engine 12. The initial response variation of the engine torque Te, which is controlled by adjusting the intake air volume Qair of the engine 12 due to the intake demand torque Tebs, can be suppressed, for example, by ensuring a sufficient net backlash elimination period.

In FIG. 2, the post-retard required torque Tesd shown by the thick dashed line Ea is set as the required value of the engine torque Te after reduction by the ignition retard control CTsd with respect to the intake required torque Tebs. The ignition retard control CTsd is started, for example, when the vehicle 10 is in a driven state with the accelerator off and the static target driving force source torque Tspts reaches the clearance torque region SPsl from the negative side due to the driver turning on the accelerator (see time t1a). At this time, if the dynamic target driving force source torque Tsptd is used to determine the start of the ignition retard control CTsd, a sudden change in the engine torque Te cannot be suppressed if the timing with the accelerator on is shifted or the actual engine torque Teact rises earlier than the dynamic target driving force source torque Tsptd, so the static target driving force source torque Tspts is used to determine the start of the ignition retard control CTsd. The post-retard demand torque Tesd is set to the lower limit torque Tllim of the backlash-reducing torque region SPsl during the period from when the ignition retard control CTsd is started until when the dynamic target driving force source torque Tsptd reaches the backlash-reducing torque region SPsl (see time t1a-t2a). This is to prevent the actual engine torque Teact from exceeding the lower limit torque Tllim of the backlash-reducing torque region SPsl by using the ignition retard control CTsd even if the actual engine torque Teact rises rapidly. Moreover, the post-retard demand torque Tesd is set to the dynamic target driving force source torque Tsptd, i.e., the slowly changing torque Tspsl, during the period from when the dynamic target driving force source torque Tsptd exceeds the lower limit torque Tllim of the backlash-reducing torque region SPsl until when it exceeds the upper limit torque Tulim of the backlash-reducing torque region SPsl (see time t2a-t3a). The ignition retard control CTsd is executed so that the actual engine torque Teact after the ignition retard control CTsd is executed becomes the slowly changing torque Tspsl. As a result, during execution of the slowly changing control CTspsl, the driving force source torque Tsp is precisely controlled to the slowly changing torque Tspsl mainly by the change in the engine torque Te. Therefore, during execution of the slowly changing control CTspsl, the MG torque Tm is not required, and the required motor torque, which is the required value of the MG torque Tm, that is, the required MG torque Tmdem, is basically set to zero. In addition, when the dynamic target driving force source torque Tsptd exceeds the upper limit torque Tulim of the backlash eliminating torque region SPsl, the post-retard required torque Tesd is gradually reduced by the torque reduction amount by the ignition retard control CTsd, and preparations for ending the ignition retard control CTsd are executed (see time t3a-t4a). As a result, during preparation for the end of the ignition retard control CTsd, deterioration of drivability due to a sudden change in torque is suppressed. In addition, the ignition retard control CTsd is completely terminated when the post-retard required torque Tesd exceeds the actual engine torque Teact, taking into account the continuity of the actual engine torque Teact (see time t4a). The post-retard required torque Tesd may be guarded by the engine lower limit torque at which the engine torque Te can be realized, so that the retard request is not made to an area where the engine torque Te cannot be realized. In addition, in order to prevent the ignition retard control CTsd from not ending because the dynamic target driving force source torque Tsptd does not exceed the upper limit torque Tulim of the backlash-eliminating torque area SPsl, the ignition retard control CTsd may be terminated if it continues for a predetermined retard time or more. This predetermined retard time is, for example, a predetermined backup timer for forcibly terminating the ignition retard control CTsd.

In this way, while the slow-change control CTspsl is being executed, the driving force source control unit 92 sets the intake required torque Tebs that is higher than the slow-change torque Tspsl by a predetermined torque Tspf, and controls the engine torque Te by setting the post-retard required torque Tesd to the slow-change torque Tspsl, and fixes the MG torque Tm by setting the required MG torque Tmdem to zero.

If the torque reduction amount by the ignition retard control CTsd deviates from the target due to some malfunction of the engine 12, etc., the post-retard required torque Tesd cannot be realized. In this case, the torque difference between the post-retard required torque Tesd and the engine torque Te after the ignition retard control CTsd may be compensated for by powering or generating the electric motor MG. For example, if the torque reduction amount by the ignition retard control CTsd is less than the target, the torque reduction amount that could not be realized is recovered by charging the battery 54 by generating electricity by the electric motor MG. In this way, when the post-retard required torque Tesd cannot be realized in the ignition retard control CTsd, the driving force source control unit 92 controls the MG torque Tm to compensate for the torque difference between the post-retard required torque Tesd and the engine torque Te after the ignition retard control CTsd. For example, the driving force source control unit 92 controls the MG torque Tm based on the actual retard amount in the ignition retard control CTsd. The compensation amount by the electric motor MG that becomes the required MG torque Tmdem is only the torque reduction amount that could not be realized by the ignition retard control CTsd, so even if the MG torque Tm is limited by the chargeable power Win or dischargeable power Wout of the battery 54, or the MG rotation speed Nm, the slow-changing torque Tspsl is easily realized solely by controlling the engine torque Te.

Figure 3 is a diagram for explaining the accurate execution of the gradual change control CTspsl when there is a request to charge the battery 54. The gradual change control CTspsl in Figure 3 differs from the gradual change control CTspsl in Figure 2 mainly in that it is executed when there is a request to charge the battery 54. This difference will be mainly explained. In Figure 3, time t1b indicates the time when the static target driving force source torque Tspts shown by the two-dot chain line Ab is changed from negative torque to positive torque by the driver's accelerator operation when the vehicle 10 is in a driven state. A dynamic target driving force source torque Tsptd shown by the thick solid line Bb is set with respect to the static target driving force source torque Tspts.

In Figure 3, a request to charge the battery 54, which is charged with power from the electric motor MG, has been made before time t1b. Therefore, the intake demand torque Tebs shown by the solid line Cb takes into account the charging demand torque Techg, which is the required value of the engine torque Te that realizes the charging demand of the battery 54 (see arrow Fa). In other words, the intake demand torque Tebs shown by the solid line Cb is set on the positive side by the charging demand torque Techg compared to the intake demand torque Tebs shown by the solid line Ca in Figure 2. Specifically, during the net backlash elimination period, the intake demand torque Tebs in FIG. 3 is set to a torque that is higher by a predetermined torque Tspf than the torque obtained by adding the charging demand torque Techg to the slow-changing torque Tspsl. For example, when the actual engine torque Teact shown by the solid line Db, which is not subjected to the ignition retard control CTsd and which includes the charging demand torque Techg, is reduced by the charging demand torque Techg, the actual engine torque Teact is set to a value that does not deviate significantly from the dynamic target driving force source torque Tsptd in the backlash elimination torque region SPsl. The charging demand for the battery 54 is made, for example, when the battery charge amount SOC becomes less than the engine start threshold SOCest, and is set as the charging demand torque Techg for the engine 12. Therefore, the input power of the battery 54 at the time of the charging demand, i.e., the charging power [W], is set to a power based on the engine rotation speed Ne and the charging demand torque Techg at that time.

3, the ignition retard control CTsd is started when the driver turns on the accelerator when the vehicle 10 is in a driven state with the accelerator off, causing the static target driving force source torque Tspts to reach the backlash-removing torque region SPsl from the negative side (see time t1b), and the ignition retard control CTsd sets the post-retard required torque Tesd shown by the thick dashed line Eb. During the period from the start of the ignition retard control CTsd until the dynamic target driving force source torque Tsptd reaches the backlash-removing torque region SPsl, the post-retard required torque Tesd is set to a torque value obtained by adding the charging required torque Techg (see arrow Fb) to the lower limit torque Tllim of the backlash-removing torque region SPsl (see time t1b-t2b). Furthermore, the post-retard required torque Tesd is set to a torque value obtained by adding the charging required torque Techg (see arrows Fb, Fc, and Fd) to the slow-changing torque Tspsl during the period from when the dynamic target driving force source torque Tsptd exceeds the lower limit torque Tllim of the backlash-reducing torque region SPsl until when it exceeds the upper limit torque Tulim of the backlash-reducing torque region SPsl (see time t2b to time t3b). The ignition retard control CTsd is executed so that the actual engine torque Teact after the ignition retard control CTsd is executed is a torque obtained by adding the charging required torque Techg to the slow-changing torque Tspsl. The charging required torque Techg is maintained at the charging required torque Techg at the start of the ignition retard control CTsd during the period from when the ignition retard control CTsd is started until when the dynamic target driving force source torque Tsptd exceeds the upper limit torque Tulim (see arrows Fa, Fb, Fc, and Fd). Therefore, while the slow-change control CTspsl is being executed, the charging required torque Techg is held at the charging required torque Techg at the start of the slow-change control CTspsl. While the slow-change control CTspsl is being executed, the MG torque Tm only needs to be set to a torque value at which the electric motor MG recovers the charging required torque Techg by generating electricity, so the required MG torque Tmdem shown by the shaded area G is basically set to the charging required torque Techg, that is, the differential torque between the dynamic target driving force source torque Tsptd (=slow-change torque Tspsl) and the post-retard required torque Tesd. As a result, while the slow-change control CTspsl is being executed, the driving force source torque Tsp is precisely controlled to the slow-change torque Tspsl solely by changes in the engine torque Te. When the dynamic target driving force source torque Tsptd exceeds the upper limit torque Tulim of the backlash-eliminating torque region SPsl, the torque reduction amount by the ignition retard control CTsd is gradually decreased (see time t3b-t4b). When the post-retard demand torque Tesd exceeds the dynamic engine torque Tebsd and the actual engine torque Teat, the ignition retard control CTsd is completely terminated (see time t4b) in consideration of the continuity of the MG torque Tm and the continuity of the actual engine torque Teat. The dynamic engine torque Tebsd is, for example, a torque value set by a first-order delay function in the step response to the intake demand torque Tebs (see dashed line H). In FIG. 3, the torque reduction amount by the ignition retard control CTsd is, for example, the difference torque between the post-retard demand torque Tesd and the dynamic engine torque Tebsd (see shaded area I). In this case, the post-retard required torque Tesd is set to a required value of the engine torque Te after it has been reduced by the ignition retard control CTsd with respect to the dynamic engine torque Tebsd. The required MG torque Tmdem indicated by the shaded area G is set to the differential torque between the dynamic target driving force source torque Tsptd and the post-retard required torque Tesd during the period in which the torque reduction amount by the ignition retard control CTsd is gradually reduced (see time t3b-t4b). After the ignition retard control CTsd ends, the required MG torque Tmdem indicated by the shaded area G is set to the differential torque between the dynamic target driving force source torque Tsptd and the dynamic engine torque Tebsd (see time t4b and after). In addition, considering the continuity with the required MG torque Tmdem before the ignition retard control CTsd is executed, the required MG torque Tmdem during the execution of the ignition retard control CTsd is set to the torque difference (= Tsptd - MIN (Tesd, Tebsd)) between the dynamic target driving force source torque Tsptd and the smaller torque value of the post-retard required torque Tesd and the dynamic engine torque Tebsd. This ensures the continuity of the required MG torque Tmdem both at the start and end of the ignition retard control CTsd.

In this way, when there is a request to charge the battery 54, the driving force source control unit 92 sets the intake request torque Tebs that is higher by a predetermined torque Tspf than the torque value obtained by adding the charging request torque Techg to the slow-change torque Tspsl while the slow-change control CTspsl is being executed, and controls the engine torque Te by setting the post-retard request torque Tesd to the torque value obtained by adding the charging request torque Techg to the slow-change torque Tspsl, and fixes the MG torque Tm by setting the request MG torque Tmdem to the charging request torque Techg. Also, the driving force source control unit 92 holds the charging request torque Techg at the value at the start of the slow-change control CTspsl while the slow-change control CTspsl is being executed.

More specifically, the driving force source control unit 92 determines whether the driving mode is the HV driving mode. If the driving force source control unit 92 determines that the driving mode is the HV driving mode, it sets the static target driving force source torque Tspts, the dynamic target driving force source torque Tsptd, the intake request torque Tebs, the dynamic engine torque Tebsd, the request MG torque Tmdem, etc., and controls the engine 12 and the electric motor MG. At this time, if there is a request to charge the battery 54, the driving force source control unit 92 takes into account the charging request torque Techg.

The driving force source control unit 92 determines whether the static target driving force source torque Tspts has reached the backlash-eliminating torque region SPsl from the negative side due to the driver's accelerator depression. If the driving force source control unit 92 determines that the static target driving force source torque Tspts has reached the backlash-eliminating torque region SPsl from the negative side, it sets the post-retard required torque Tesd, executes the ignition retard control CTsd, and executes the gradual change control CTspsl.

Figure 4 is a flowchart that explains the main control operations of the electronic control device 90, and is a flowchart that explains the control operations for appropriately suppressing tip-in shock when two driving power sources SP, the engine 12 and the electric motor MG, are available, and is executed, for example, repeatedly.

4, each step of the flow chart corresponds to a function of the driving force source control unit 92. In step (hereinafter, step will be omitted) S10, it is determined whether the driving mode is the HV driving mode. If the determination in S10 is negative, this routine is terminated. If the determination in S10 is positive, in S20, the static target driving force source torque Tspts, the dynamic target driving force source torque Tsptd, the intake demand torque Tebs, the dynamic engine torque Tebsd, the demand MG torque Tmdem, etc. are set, and the engine 12 and the electric motor MG are controlled. At this time, if there is a demand for charging the battery 54, the demand charging torque Techg is taken into account. Next, in S30, it is determined whether the static target driving force source torque Tspts has reached the backlash elimination torque region SPsl from the negative side due to the driver turning on the accelerator. If the determination in S30 is negative, this routine is terminated. If the determination in S30 is positive, then in S40, the post-retard required torque Tesd is set, the ignition retard control CTsd is executed, and the slow change control CTspsl is executed.

As described above, according to this embodiment, in the backlash-eliminating torque region SPsl, the engine 12 and the electric motor MG are controlled so that the driving force source torque Tsp is a slowly changing torque Tspsl with a smaller rising gradient than outside the backlash-eliminating torque region SPsl, making it easier to suppress tip-in shock when the vehicle 10 is switched from a driven state to a driving state. Furthermore, in order to realize the slowly changing torque Tspsl in the backlash-eliminating torque region SPsl, the engine torque Te is controlled with the MG torque Tm fixed, so that in the backlash-eliminating torque region SPsl, the driving force source torque Tsp is precisely controlled to the slowly changing torque Tspsl solely by the change in the engine torque Te. Therefore, when two driving force sources SP, the engine 12 and the electric motor MG, can be used, the tip-in shock can be appropriately suppressed.

In addition, according to this embodiment, during execution of the slow-change control CTspsl, the intake required torque Tebs is set to a predetermined torque Tspf higher than the slow-change torque Tspsl, and the post-retard required torque Tesd is set to the slow-change torque Tspsl to control the engine torque Te, and the required MG torque Tmdem is set to zero to fix the MG torque Tm. Therefore, within the backlash-eliminating torque region SPsl, the driving force source torque Tsp is appropriately and precisely controlled to the slow-change torque Tspsl solely by changes in the engine torque Te.

In addition, according to this embodiment, when there is a charge request for the battery 54, during execution of the slow-change control CTspsl, the intake request torque Tebs is set to a torque value obtained by adding the charging request torque Techg to the slow-change torque Tspsl by a predetermined torque Tspf, and the post-retard request torque Tesd is set to a torque value obtained by adding the charging request torque Techg to the slow-change torque Tspsl, thereby controlling the engine torque Te, and the required MG torque Tmdem is set to the charging request torque Techg, thereby fixing the MG torque Tm. Therefore, while the charge request for the battery 54 is realized, within the backlash-eliminating torque region SPsl, the driving force source torque Tsp is precisely controlled to the slow-change torque Tspsl mainly by changes in the engine torque Te.

In addition, according to this embodiment, while the slow-change control CTspsl is being executed, the charging request torque Techg is held at the value at the start of the slow-change control CTspsl, so that even if the charging request for the battery 54 fluctuates while the slow-change control CTspsl is being executed, the driving force source torque Tsp is accurately controlled to the slow-change torque Tspsl.

In addition, according to this embodiment, when the post-retard required torque Tesd cannot be realized in the ignition retard control CTsd, the MG torque Tm is controlled to compensate for the torque difference between the post-retard required torque Tesd and the engine torque Te after the ignition retard control CTsd, so that the driving force source torque Tsp is more accurately controlled to the slowly changing torque Tspsl within the backlash-eliminating torque region SPsl.

The above describes in detail an embodiment of the present invention based on the drawings, but the present invention can also be applied in other aspects.

For example, in the above-mentioned embodiment, if the tip-in shock is greater during lockup when the LU clutch 40 is fully engaged than during non-lockup times, then executing the gentle change control CTspsl with precision is a useful control during lockup of the LU clutch 40.

In the above embodiment, a planetary gear type automatic transmission was used as the automatic transmission 24, but the present invention is not limited to this. The automatic transmission 24 may be a synchronous mesh type parallel two-shaft automatic transmission including a known DCT (Dual Clutch Transmission), a known belt type continuously variable transmission, or the like. Alternatively, the automatic transmission 24 does not necessarily have to be provided. The engine 12 may be an engine with a supercharger, or the like. In short, the present invention can be applied to any vehicle that is equipped with a driving force source including an engine and an electric motor, and a power transmission device that transmits the output torque of the driving force source to the drive wheels.

In addition, in the above-mentioned embodiment, the torque converter 22 is used as the fluid transmission device, but this is not limited to the embodiment. For example, instead of the torque converter 22, other fluid transmission devices such as a fluid coupling that does not have a torque amplifying effect may be used as the fluid transmission device. Alternatively, the fluid transmission device does not necessarily have to be provided, and may be replaced with, for example, a starting clutch.

The above is merely one embodiment, and the present invention can be implemented in various forms with various modifications and improvements based on the knowledge of those skilled in the art.

10: vehicle 12: engine 14: drive wheels 16: power transmission device 54: battery (electricity storage device)
90: Electronic control device (control device)
92: Driving force source control unit MG: Electric motor SP: Driving force source

Claims (5)

A control device for a vehicle including a driving force source including an engine and an electric motor, and a power transmission device that transmits an output torque of the driving force source to a driving wheel,
a driving force source control unit that controls the engine and the electric motor so that within a predetermined torque range of the output torque of the driving force source, where a direction of removing backlash in the power transmission device is reversed when the driving torque is changed from negative torque to positive torque, the output torque of the driving force source is made a slowly changing torque having a smaller increasing gradient than that outside the predetermined torque range,
the driving force source control unit controls an output torque of the engine while keeping an output torque of the electric motor fixed so as to realize the slowly changing torque,
the driving force source control unit, during execution of the slow-changing control for realizing the slow-changing torque, sets an intake required torque which is a required value of the output torque of the engine controlled by adjusting the amount of intake air of the engine, which is higher than the slow-changing torque by a predetermined torque, and controls the output torque of the engine by setting a post-retard required torque which is a required value of the output torque of the engine after the intake required torque has been reduced by ignition retard control to the slow-changing torque, and sets a required electric motor torque which is a required value of the output torque of the electric motor to zero, thereby fixing the output torque of the electric motor;
A control device for a vehicle , wherein the predetermined torque amount is a torque amount that is determined in advance so that the slowly changing torque can be formed by the ignition retard control . 2. The vehicle control device according to claim 1, wherein, when the post-retard required torque exceeds an upper limit torque of the predetermined torque region, the driving force source control unit gradually reduces the torque reduction amount due to the ignition retard control in the post-retard required torque, thereby preparing to end the ignition retard control . 3. The control device for a vehicle according to claim 1 or 2, wherein, when there is a request to charge a power storage device that charges with electric power from the electric motor generated by motive power of the engine, during execution of the slow-change control, the driving force source control unit sets the intake required torque that is higher by the predetermined torque than a torque value obtained by adding a charging required torque, which is a required value of an output torque of the engine that realizes the charging request, to the slow-change torque, and controls the output torque of the engine by setting the post-retard required torque to a torque value obtained by adding the charging required torque to the slow-change torque, and keeps the output torque of the electric motor fixed by setting the required electric motor torque to the charging required torque instead of setting it to zero. The vehicle control device according to claim 3, characterized in that the driving force source control unit maintains the charging request torque at a value at the start of the slow change control while the slow change control is being executed. 3. The vehicle control device according to claim 1, wherein, when the post-retard required torque cannot be realized in the ignition retard control, instead of keeping the output torque of the electric motor in a fixed state, the driving force source control unit controls the output torque of the electric motor so as to compensate for a torque difference between the post-retard required torque and the output torque of the engine after the ignition retard control.

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