JP7188269B2 - vehicle controller - Google Patents

Description

The present invention relates to a control device for a vehicle equipped with an automatic transmission forming part of a power transmission path between an engine and drive wheels.

2. Description of the Related Art Control devices for vehicles having an engine and an automatic transmission forming part of a power transmission path between the engine and drive wheels are well known. For example, the driving force control device described in Patent Document 1 is one of them. This patent document 1 discloses that a target driving force is determined based on the amount of operation of the accelerator pedal by the driver and the vehicle speed, and a target gear ratio and a target engine torque are set based on the target driving force. ing.

JP 2006-298317 A

By the way, for example, when the actual engine torque is insufficient with respect to the target engine torque for realizing the target driving force due to an external factor such as low atmospheric pressure, the gear ratio of the automatic transmission can be changed to the downshift side. It is conceivable to realize the target driving force. At this time, when the target driving force is calculated based on the amount of operation of the accelerator pedal by the driver using a single driving force map, the target driving force does not change even when the actual engine torque is insufficient due to external factors. do not have. Then, even if the automatic transmission is downshifted to make up for the lack of driving force, the target engine torque is reduced by the change in the gear ratio to match the target driving force. cannot make up for the shortfall of

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and its object is to realize a target driving force when the gear ratio is changed based on a predetermined external factor. An object of the present invention is to provide a control device for a vehicle.

The gist of the first invention is (a) a control device for a vehicle equipped with an engine and an automatic transmission forming part of a power transmission path between the engine and drive wheels, (b) a target driving force calculation unit for calculating a target driving force of the vehicle based on the acceleration operation amount of the driver; and (c) the calculated target driving force and the calculated target driving force (d) the target driving force calculation unit calculates a target value of the output torque of the engine based on the basic gear ratio of the automatic transmission based on the basic gear ratio is changed to the post-change gear ratio based on a predetermined external factor, the post-correction drive force obtained by correcting the calculated target drive force by the value of the ratio of the post-change gear ratio to the basic gear ratio is (e) when the basic gear ratio is changed to the post-change gear ratio, the engine control unit calculates the To calculate a target value of engine output torque .

According to the first aspect of the invention, when the basic gear ratio of the automatic transmission based on the target driving force is changed to the changed gear ratio based on a predetermined external factor, the changed gear ratio is changed to the basic gear ratio. The post-correction drive force is calculated by correcting the target drive force by the value of the ratio to the gear ratio, and the target value of the output torque of the engine is calculated based on the post-correction drive force and the post-change gear ratio. , the target value of the output torque of the engine is calculated based on the target driving force before correction and the gear ratio after change. Target value can be changed. Therefore, when the gear ratio is changed based on a predetermined external factor, the target driving force can be achieved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram for explaining a schematic configuration of a vehicle to which the present invention is applied, and is a diagram for explaining main parts of a control system and control functions for various controls in the vehicle; FIG. 4 is a block diagram illustrating a main part of the control operation of the electronic control unit, that is, the control operation for realizing the target driving force when the target gear ratio is changed based on a predetermined external factor; 4 is a flow chart for explaining a main part of the control operation of the electronic control unit, that is, the control operation for realizing the target driving force when the target gear ratio is changed based on a predetermined external factor; In the control operation for performing engine control and transmission control using the driver driving force directly calculated based on the accelerator opening, when the target gear ratio is changed from the basic gear ratio to the post-change gear ratio FIG. 10 is a block diagram for explaining an example, and is a diagram showing a comparative example of the present embodiment;

In an embodiment of the present invention, the automatic transmission is, for example, a known planetary gear type automatic transmission, a known synchronous mesh parallel twin shaft automatic transmission, or a synchronous mesh parallel twin shaft automatic transmission. Examples include a known DCT (Dual Clutch Transmission) type having two shafts, and a known belt-type or toroidal-type continuously variable transmission.

Further, the belt-type continuously variable transmission includes a primary pulley and a secondary pulley in which a groove width between a fixed sheave and a movable sheave is changed by supplying hydraulic pressure to a hydraulic actuator, and the primary pulley. The continuously variable transmission includes the secondary pulley and a transmission belt wound around the secondary pulley. The vehicle includes a hydraulic control circuit that controls pulley hydraulic pressure as working hydraulic pressure supplied to the hydraulic actuator. The hydraulic control circuit may be configured, for example, to control the flow of hydraulic fluid to the hydraulic actuator, resulting in pulley hydraulic pressure. By controlling each thrust (=pulley hydraulic pressure×pressure receiving area) in the primary pulley and the secondary pulley by such a hydraulic control circuit, a target shift is realized while preventing the transmission belt from slipping. Shift control is executed as follows. In a broad sense, the concept of a belt-type continuously variable transmission includes a chain-type continuously variable transmission.

In addition, the gear ratio in the above-mentioned continuously variable transmission or the like is "the rotational speed of the rotating member on the input side/the rotational speed of the rotating member on the output side". For example, the gear ratio of the continuously variable transmission is "rotational speed of primary pulley/rotational speed of secondary pulley". The high side of the gear ratio is the high vehicle speed side on which the gear ratio becomes smaller. The low side of the gear ratio is the low vehicle speed side on which the gear ratio increases. For example, the lowest gear ratio is the gear ratio on the lowest vehicle speed side, which is the lowest vehicle speed side, and is the maximum gear ratio at which the gear ratio has the largest value.

Further, the engine is, for example, a gasoline engine or a diesel engine that generates power by burning fuel. Also, the vehicle may include a rotating machine or the like in addition to the engine.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a diagram for explaining a schematic configuration of a vehicle 10 to which the present invention is applied, and is a diagram for explaining control functions and main parts of a control system for various controls in the vehicle 10. As shown in FIG. In FIG. 1 , a vehicle 10 includes an engine 12 , drive wheels 14 , and a power transmission device 16 provided in a power transmission path between the engine 12 and the drive wheels 14 .

The power transmission device 16 includes a well-known torque converter 20 as a hydrodynamic transmission device connected to the engine 12, a turbine shaft 22 connected to the torque converter 20, a turbine shaft 22 connected to the torque converter 20, a turbine shaft 22 connected to the torque converter 20, and a turbine shaft 22 connected to the torque converter 20. A forward/reverse switching device 24 connected to the shaft 22, an input shaft 26 connected to the forward/reverse switching device 24, a belt-type continuously variable transmission 28 connected to the input shaft 26, and a continuously variable transmission 28 connected to the It has an output shaft 30, a reduction gear mechanism 32, a differential gear 34, and the like. The power transmission device 16 also includes left and right drive shafts 36 connected to a differential gear 34 and the like. In the power transmission device 16, the power output from the engine 12 is driven through the torque converter 20, the forward/reverse switching device 24, the continuously variable transmission 28, the reduction gear mechanism 32, the differential gear 34, the drive shaft 36, etc. in sequence. transmitted to the wheel 14; The power is also synonymous with torque and force unless otherwise specified.

The engine 12 is a power source for running the vehicle 10, and is a known internal combustion engine such as a gasoline engine or a diesel engine. The engine 12 is controlled by an electronic control unit 80, which will be described later, such as a throttle actuator, a fuel injection device, an ignition device, etc. provided in the vehicle 10, thereby controlling the engine torque Te, which is the output torque of the engine 12. .

The torque converter 20 includes a pump impeller 20 p connected to the engine 12 and a turbine impeller 20 t connected to the turbine shaft 22 . Further, the torque converter 20 is provided with a known lockup clutch LU capable of directly connecting between the pump impeller 20p and the turbine impeller 20t, that is, between the input and output rotating members of the torque converter 20. FIG.

The power transmission device 16 includes a mechanical oil pump 38 connected to the pump impeller 20p. The oil pump 38 is rotationally driven by the engine 12 to control the shift of the continuously variable transmission 28, generate a belt squeezing pressure in the continuously variable transmission 28, and operate a forward clutch C1 and a reverse brake to be described later. Hydraulic oil provided in the vehicle 10 is used to generate the source pressure of the hydraulic pressure for switching the operating states such as the engaged state and the disengaged state of each of B1 and for switching the operating state of the lockup clutch LU. It is supplied to the control circuit 40 .

The forward/reverse switching device 24 includes a double pinion type planetary gear device 24p, a forward clutch C1, and a reverse brake B1. The planetary gear device 24p is a differential mechanism having three rotating elements, a sun gear 24s, a carrier 24c, and a ring gear 24r. The sun gear 24 s is connected to the turbine shaft 22 . Carrier 24 c is connected to input shaft 26 . The ring gear 24r is selectively connected to the case 18 via a reverse brake B1. The carrier 24c and the sun gear 24s are selectively connected via a forward clutch C1. Both the forward clutch C1 and the reverse brake B1 are known hydraulic wet friction engagement devices that are frictionally engaged by respective hydraulic actuators. The operating states of the forward clutch C1 and the reverse brake B1 are switched by supplying the control pressure, which is the operating oil pressure regulated by the hydraulic control circuit 40, to the hydraulic actuator. In the forward/reverse switching device 24, when the forward clutch C1 is engaged and the reverse brake B1 is released, the power transmission device 16 forms a forward power transmission path. When the reverse brake B1 is engaged and the forward clutch C1 is released, the power transmission device 16 forms a reverse power transmission path. Further, when both the forward clutch C1 and the reverse brake B1 are released, the power transmission device 16 is brought into a neutral state in which power transmission is disabled.

The continuously variable transmission 28 is wound around a primary pulley 50 with a variable effective diameter connected to the input shaft 26, a secondary pulley 52 with a variable effective diameter connected to the output shaft 30, and these pulleys 50, 52. and a transmission belt 54 as a transmission element. The continuously variable transmission 28 transmits power via frictional force between the pulleys 50 and 52 and the transmission belt 54, and transmits the power of the engine 12 to the drive wheels 14 side. Thus, the continuously variable transmission 28 is an automatic transmission that forms part of the power transmission path between the engine 12 and the drive wheels 14 . The frictional force is the same as the pinching force, which is the pressure with which the transmission belt 54 is pinched by the pulleys 50 and 52, and is also referred to as the belt pinching force. This belt clamping force is the belt torque capacity Tcvt, which is the torque capacity of the transmission belt 54 in the continuously variable transmission 28 .

The primary pulley 50 includes a fixed sheave 50a connected to the input shaft 26, a movable sheave 50b provided so as to be movable in the axial direction and unable to rotate relative to the fixed sheave 50a about the axis of the input shaft 26, and a hydraulic actuator 50c as an actuator that applies a primary thrust Win to the movable sheave 50b. The primary thrust Win is the thrust of the primary pulley 50 (=primary pressure Pin×pressure receiving area) for changing the V-groove width between the fixed sheave 50a and the movable sheave 50b. That is, the primary thrust Win is the thrust of the primary pulley 50 that clamps the transmission belt 54 and is applied by the hydraulic actuator 50c. The primary pressure Pin is the hydraulic pressure supplied to the hydraulic actuator 50c by the hydraulic control circuit 40, and is the pulley hydraulic pressure that produces the primary thrust Win. The secondary pulley 52 includes a fixed sheave 52a connected to the output shaft 30 and a movable sheave 52b provided so as to be movable in the axial direction and unable to rotate relative to the fixed sheave 52a about the axis of the output shaft 30. and a hydraulic actuator 52c as an actuator for applying a secondary thrust Wout to the movable sheave 52b. The secondary thrust Wout is the thrust of the secondary pulley 52 (=secondary pressure Pout×pressure receiving area) for changing the V-groove width between the fixed sheave 52a and the movable sheave 52b. That is, the secondary thrust Wout is the thrust of the secondary pulley 52 that clamps the transmission belt 54 and is applied by the hydraulic actuator 52c. The secondary pressure Pout is the hydraulic pressure supplied to the hydraulic actuator 52c by the hydraulic control circuit 40, and is the pulley hydraulic pressure that produces the secondary thrust Wout.

In the continuously variable transmission 28, the primary pressure Pin and the secondary pressure Pout are controlled by a hydraulic control circuit 40 driven by an electronic control device 80, which will be described later, so that the primary thrust Win and the secondary thrust Wout are controlled. be. As a result, in the continuously variable transmission 28, the V-groove widths of the pulleys 50 and 52 are changed to change the winding diameter (=effective diameter) of the transmission belt 54, thereby changing the gear ratio γ (= input shaft rotational speed Nin/output The shaft rotation speed Nout) is changed, and the belt squeezing force is controlled so that the transmission belt 54 does not slip. That is, by controlling the primary thrust force Win and the secondary thrust force Wout respectively, belt slip, which is slip between the pulleys 50 and 52 and the transmission belt 54, is prevented while the gear ratio γ of the continuously variable transmission 28 is increased. A target gear ratio γtgt. The input shaft rotation speed Nin is the rotation speed of the input shaft 26 and is the same as the rotation speed of the primary pulley 50 . Also, the output shaft rotation speed Nout is the rotation speed of the output shaft 30 and is the same as the rotation speed of the secondary pulley 52 .

In the continuously variable transmission 28, when the primary pressure Pin is increased, the width of the V groove of the primary pulley 50 is narrowed to reduce the gear ratio γ. Reducing the gear ratio γ means that the continuously variable transmission 28 is upshifted. On the other hand, in the continuously variable transmission 28, when the primary pressure Pin is lowered, the width of the V groove of the primary pulley 50 is widened and the gear ratio γ is increased. Enlarging the gear ratio γ means that the continuously variable transmission 28 is downshifted. In the continuously variable transmission 28, belt slippage is prevented by the primary thrust force Win and the secondary thrust force Wout, and the target gear ratio γtgt is realized by the mutual relationship between the primary thrust force Win and the secondary thrust force Wout. The target speed change cannot be achieved with only one thrust force. The gear ratio of the continuously variable transmission 28 is changed by changing the thrust ratio τ (=Wout/Win), which is the value of the ratio between the primary thrust Win and the secondary thrust Wout, due to the mutual relationship between the primary pressure Pin and the secondary pressure Pout. γ is changed. The thrust ratio τ is the value of the ratio of the secondary thrust Wout to the primary thrust Win. For example, as the thrust ratio τ is increased, the gear ratio γ is increased, that is, the continuously variable transmission 28 is downshifted.

The vehicle 10 includes an electronic control unit 80 as a controller including control units of the vehicle 10 related to control of the engine 12, the continuously variable transmission 28, and the like. 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. The electronic control unit 80 executes output control of the engine 12, speed change control and belt squeezing pressure control of the continuously variable transmission 28, hydraulic control for switching the operation state of each of the engagement devices (C1, B1, LU), and the like. The electronic control unit 80 is configured separately for engine control, hydraulic control, etc., as required.

The electronic control unit 80 includes various sensors provided in the vehicle 10 (for example, an engine rotation speed sensor 60, a turbine rotation speed sensor 62, an input rotation speed sensor 64, an output rotation speed sensor 66, an accelerator opening sensor 68, a throttle valve Various signals based on values detected by the opening sensor 70, etc. (for example, the engine rotation speed Ne, which is the rotation speed of the engine 12, the turbine rotation speed Nt, which is the rotation speed of the turbine shaft 22, the input shaft rotation speed Nin, the vehicle speed V, etc.) Corresponding output shaft rotation speed Nout, accelerator opening pap, throttle valve opening tap which is the opening of the electronic throttle valve, etc.) are supplied respectively. The accelerator opening pap is a driver's acceleration operation amount representing the magnitude of the driver's acceleration operation, and is an operation amount of an accelerator operation member such as an accelerator pedal provided in the vehicle 10, that is, an accelerator operation amount. The accelerator opening pap is also the amount of output demanded by the driver for the vehicle 10 . In addition to the accelerator opening pap, the throttle valve opening tap or the like can also be used as the driver's acceleration operation amount.

Further, from the electronic control unit 80, various command signals (eg, an engine control command signal Se for controlling the engine 12, a continuously variable transmission A CVT hydraulic control command signal Scvt for controlling the shift of the gear 28 and the belt clamping pressure, etc., a CB hydraulic control command signal Scb for controlling the operating states of the forward clutch C1 and the reverse brake B1, and a lockup clutch. LU oil pressure control command signal Slu for controlling the operating state of the LU, etc.) are respectively output.

In order to realize various controls in the vehicle 10, the electronic control unit 80 includes a target drive force calculation means or target drive force calculation section 82, an engine control means or engine control section 84, and a transmission control means or transmission control section 86. It has

The target driving force calculation unit 82 applies the accelerator opening pap and the vehicle speed V to a driving force map, which is a relationship obtained experimentally or by design in advance and stored, that is, a predetermined relationship, for example, to calculate the driver driving force. Calculate the force Fddrv. The driver driving force Fddrv is the required driving force of the vehicle 10 requested by the driver and is also the target driving force of the vehicle 10 . Thus, the target driving force calculation unit 82 calculates the driver driving force Fddrv based on the accelerator opening pap. A method of converting the accelerator opening pap into a required throttle valve opening required by the driver, converting the required throttle valve opening into a required engine torque required by the driver, and converting the required engine torque into driver driving force. However, in the method of directly calculating the driver driving force Fddrv based on the accelerator opening pap, the vehicle controllability can be improved by directly designing the driving force Fd.

The engine control section 84 controls the engine 12 so as to obtain the requested engine torque Te. Specifically, the engine control unit 84 calculates the target engine torque Tetgt, which is the target value of the engine torque Te, based on the driver driving force Fddrv, taking into consideration the gear ratio γ of the continuously variable transmission 28 and the like. The engine control unit 84 outputs to the engine 12 an engine control command signal Se for controlling the engine 12 so as to obtain an engine torque Te that achieves the target engine torque Tetgt.

The transmission control unit 86 adjusts the gear ratio γ of the continuously variable transmission 28 and the belt squeezing pressure so as to achieve the target gear ratio γtgt of the continuously variable transmission 28 while preventing belt slippage of the continuously variable transmission 28 . to control.

Specifically, the transmission control unit 86 calculates the basic target input shaft rotational speed Nintgtb by applying the driver driving force Fddrv and the vehicle speed V to a predetermined relationship, such as a shift map. The transmission control unit 86 calculates a basic gear ratio γb (=Nintgtb/Nout) of the continuously variable transmission 28 based on this basic target input shaft rotational speed Nintgtb. This shift map corresponds to, for example, a shift condition for achieving both power performance and fuel efficiency, and a basic target input shaft rotation speed Nintgtb that makes the engine operating point along the optimum fuel efficiency line of the engine 12 is set. is predetermined as follows. The engine operating point is the operating point of the engine 12 determined by the engine rotation speed Ne and the engine torque Te. The optimal fuel efficiency line is a known relationship that is predetermined so as to achieve both power performance and fuel efficiency within a two-dimensional coordinate system defined by the engine rotation speed Ne and the engine torque Te. The basic transmission gear ratio γb is a basic transmission gear ratio used in basic transmission control that achieves both power performance and fuel efficiency as described above, for example, when the atmospheric pressure is normal pressure and the intake air temperature is normal temperature.

If only the basic gear shift control is used, the basic gear ratio γb is calculated as the target gear ratio γtgt. A gear ratio γtgt is calculated. Each gear ratio calculation control calculates the gear ratio γ based on a predetermined external factor. Therefore, if a gear ratio γ other than the basic gear ratio γb is adopted through arbitration, the target gear ratio γtgt is changed from the basic gear ratio γb. The changed post-change transmission gear ratio γa. The basic gear ratio γb is the gear ratio γ of the continuously variable transmission 28 based on the driver driving force Fddrv at normal pressure and room temperature, and the changed gear ratio γa is the basic gear ratio γb based on a predetermined external factor. It is the gear ratio γ of the continuously variable transmission 28 that has been changed.

The predetermined external factors are external environments such as atmospheric pressure, intake air temperature, and climbing slopes. As the atmospheric pressure is lower than normal pressure or as the intake air temperature is higher than normal temperature, the actual engine torque Te, which is the actual engine torque Te, tends to become insufficient with respect to the target engine torque Tetgt. Further, there are situations where it is desired to increase the driving force Fd on an uphill road, and there are situations where it is desired to increase the deceleration on a downhill road. Therefore, when the atmospheric pressure is lower than the normal pressure, when the intake air temperature is higher than the normal temperature, or when driving on an uphill road, the target gear ratio γtgt is changed from the basic gear ratio γb to the downshift side. preferably The transmission control unit 86 calculates the target input shaft rotation speed Nintgtp based on the atmospheric pressure, calculates the target input shaft rotation speed Nintgtt based on the intake air temperature, and calculates the target input shaft rotation speed Nintgtt based on the road gradient. Each external factor target input shaft rotation speed Nintgte is calculated based on each predetermined external factor such as calculating Nintgts. The transmission control unit 86 selects a target input shaft rotation speed Nintgt that is the maximum value of the basic target input shaft rotation speed Nintgtb and the external factor target input shaft rotation speed Nintgte, and sets the selected target input shaft rotation speed Nintgt to Based on this, the target gear ratio γtgt of the continuously variable transmission 28 is calculated. When the basic target input shaft rotation speed Nintgtb is selected, the target gear ratio γtgt is set to the basic gear ratio γb. When the external factor target input shaft rotation speed Nintgte is selected, the target gear ratio γtgt is set to the post-change gear ratio γa that is changed to the downshift side of the basic gear ratio γb.

The transmission control unit 86 calculates the target primary thrust Wintgt and the target secondary thrust Wouttgt for achieving the target gear ratio γtgt of the continuously variable transmission 28 while preventing belt slippage of the continuously variable transmission 28 . The transmission control unit 86 determines a target primary pressure Pintgt and a target secondary pressure Pouttgt that realize the target primary thrust force Wintgt and the target secondary thrust force Wouttgt, and controls the primary pressure Pintgt and the target secondary pressure Pouttgt to achieve the target primary pressure Pintgt and the target secondary pressure Pouttgt. A CVT hydraulic control command signal Scvt for controlling the secondary pressure Pout is output to the hydraulic control circuit 40 .

FIG. 4 shows the control operation for performing engine control and transmission control using the driver driving force Fddrv directly calculated based on the accelerator opening pap. FIG. 10 is a block diagram illustrating an example of a change to a gear ratio γa, and showing a comparative example of the present embodiment; FIG. In FIG. 4, when the actual engine torque Te is insufficient with respect to the target engine torque Tetgt due to a predetermined external factor, the shortage of the actual engine torque Te is compensated to realize the driver driving force Fddrv which is the target driving force Fd. Therefore, the target gear ratio γtgt is changed to a large post-change gear ratio γa that is on the downshift side of the basic gear ratio γb. However, even when the actual engine torque Te is insufficient due to a predetermined external factor, the driver driving force Fddrv does not change, and the target engine torque Tetgt is determined based on the driver driving force Fddrv, taking into account the post-change gear ratio γa and the like. calculated as Then, even if the continuously variable transmission 28 is downshifted in order to make up for the shortage of the driving force Fd, the increase in the target gear ratio γtgt reduces the target engine torque Tetgt, thereby increasing the driver driving force Fddrv. be aligned. Therefore, the control operation as shown in FIG. 4 cannot make up for the shortage of the driving force Fd. Such a problem becomes conspicuous particularly when the statically designed driver driving force Fddrv is calculated using a single driving force map assuming normal pressure and room temperature. Further, in the continuously variable transmission 28, it is possible to set a plurality of driving force maps for each arbitrary gear ratio γ. It is not appropriate to have multiple driving force maps corresponding to .

To address the above-described problem, the electronic control unit 80 increases the driving force Fd by the change in the target gear ratio γtgt from the basic gear ratio γb to the post-change gear ratio γa. A post-correction driving force Fdcor is calculated using the basic gear ratio γb and the post-change gear ratio γa, and the target engine torque Tetgt is calculated based on the post-correction driving force Fdcor in consideration of the post-change gear ratio γa and the like. calculate. In this embodiment, the change in the target gear ratio γtgt from the basic gear ratio γb to the post-change gear ratio γa is defined as a gear ratio change rate R (=γa/ γb).

FIG. 2 is a block diagram for explaining the essential part of the control operation of the electronic control unit 80, that is, the control operation for realizing the target driving force Fd when the target gear ratio γtgt is changed based on a predetermined external factor. be. In other words, FIG. 2 shows that the target gear ratio γtgt changes from the basic gear ratio γb in the control operation for performing engine control and transmission control using the driver driving force Fddrv directly calculated based on the accelerator opening pap. FIG. 10 is a block diagram illustrating an example of a case where the transmission gear ratio is changed to the post-change gear ratio γa, and is a diagram showing the present embodiment.

In FIG. 2, in block B10 (hereinafter, the block is omitted) corresponding to the function of target driving force calculation section 82, driver driving force Fddrv is calculated based on accelerator opening pap and the like.

At B20 corresponding to the function of the transmission control section 86, the basic gear ratio γb of the continuously variable transmission 28 is calculated based on the driver driving force Fddrv and the like. Further, the post-change gear ratio γa is calculated based on a predetermined external factor, and the target gear ratio γtgt is changed from the basic gear ratio γb to the post-change gear ratio γa.

At B30 corresponding to the function of the target driving force calculation section 82, the driver driving force Fddrv is converted into a correction turbine torque Ttcor. Specifically, the correction turbine torque Ttcor is calculated by applying the driver driving force Fddrv and the basic gear ratio γb to the following equation (1). In the following equation (1), "rw" is the tire effective radius of the drive wheels 14, and "i" is the reduction ratio of the reduction gear mechanism 32, the differential gear 34, etc. in the power transmission path from the output shaft 30 to the drive wheels 14. is. The turbine torque Tt is torque on the turbine shaft 22, and the correction turbine torque Ttcor is the turbine torque Tt used when correcting the driver driving force Fddrv to the corrected driving force Fdcor.

Ttcor=(Fddrv×rw)÷(γb×i) (1)

At B40 corresponding to the function of the target driving force calculation unit 82, the correction turbine torque Ttcor is converted into the post-correction driving force Fdcor. Specifically, the post-correction driving force Fdcor is calculated by applying the correction turbine torque Ttcor and the post-change gear ratio γa to the following equation (2). In the following formula (2), "i" and "rw" are the same as in the above formula (1).

Fdcor=Ttcor×γa×i÷rw (2)

As is clear from the above formulas (1) and (2), the target driving force calculation unit 82 calculates the corrected driving force Fdcor (= Fddrv×R) is calculated. The reason why the post-correction driving force Fdcor is calculated by converting the driver driving force Fddrv into the correction turbine torque Ttcor is to dynamically reflect the gear ratio change rate R in the driver driving force Fddrv. In addition, physical items to be considered such as loss and inertia can be reflected in the formulas (1) and (2).

In B50 corresponding to the function of the engine control unit 84, the corrected driving force Fdcor is converted into the target turbine torque Tttgt, which is the target value of the turbine torque Tt. Specifically, the target turbine torque Tttgt is calculated by applying the post-correction driving force Fdcor and the post-change gear ratio γa to the following equation (3). In the following formula (3), "rw" and "i" are the same as in the above formula (1).

Tttgt=(Fdcor×rw)/(γa×i) (3)

At B60 corresponding to the function of the engine control unit 84, the target turbine torque Tttgt is converted into the target engine torque Tetgt. Specifically, the target engine torque Tetgt is calculated by applying the target turbine torque Tttgt to the following equation (4). In the following equation (4), "t" is the torque ratio of the torque converter 20 (=turbine torque Tt/pump torque Tp (=engine torque Te)). The torque ratio t is a function of the speed ratio e (=turbine rotation speed Nt/pump rotation speed Np (=engine rotation speed Ne)) of the torque converter 20, and is a predetermined relationship between the speed ratio e and the torque ratio t. is calculated by applying the actual speed ratio e to . Thus, the engine control unit 84 calculates the target engine torque Tetgt based on the post-correction driving force Fdcor and the post-change gear ratio γa.

Tetgt=Tttgt/t (4)

FIG. 3 is a flow chart for explaining the main part of the control operation of the electronic control unit 80, that is, the control operation for realizing the target driving force Fd when the target gear ratio γtgt is changed based on a predetermined external factor. , for example, is executed repeatedly.

In FIG. 3, first, in step S10 corresponding to the function of the target driving force calculation unit 82 (hereinafter, step is omitted), the target driving force of the vehicle 10 is set to a static design value based on the accelerator opening pap and the like. A certain driver driving force Fddrv is calculated. Next, in S20 corresponding to the function of the transmission control unit 86, it is determined whether or not the statically designed driving force characteristic requires a dynamic change in the driving force. It is determined whether or not to change from the basic gear ratio γb, which is the basic gear ratio calculated by the control, to the post-change gear ratio γa. If the determination in S20 is affirmative, in S30 corresponding to the function of the target driving force calculation unit 82, the correction turbine torque Ttcor is calculated based on the driver driving force Fddrv and the basic gear ratio γb (the above equation ( 1) see). Next, in S40 corresponding to the function of the target driving force calculation unit 82, the post-correction driving force Fdcor is calculated based on the correction turbine torque Ttcor and the post-change gear ratio γa, which is the current target gear ratio (formula ( 2) See). If the determination in S20 is negative, in S50 corresponding to the function of the target driving force calculation section 82, the processing in S30 is skipped, and the driver driving force Fddrv is used as the corrected driving force Fdcor. Following S40 or S50, in S60 corresponding to the function of the engine control unit 84, the target turbine torque Tttgt is calculated based on the post-correction driving force Fdcor and the post-change gear ratio γa (equation (3 )reference). Next, in S70 corresponding to the function of the engine control section 84, the target engine torque Tetgt is calculated based on the target turbine torque Tttgt (see the above formula (4)).

As described above, according to the present embodiment, the basic gear ratio γb of the continuously variable transmission 28 based on the driver's driving force Fddrv is changed based on a predetermined external factor. A corrected driving force Fdcor (=Fddrv×R) is calculated by correcting the driver driving force Fddrv by a gear ratio change rate R (=γa/γb), which is a value of the ratio to γb. Since the target engine torque Tetgt is calculated based on the gear ratio γa, compared to calculating the target engine torque Tetgt based on the driver driving force Fddrv and the changed gear ratio γa (see FIG. 4), the gear ratio The target engine torque Tetgt can be increased by the rate of change R. Therefore, the target driving force Fd can be achieved when the target gear ratio γtgt is changed based on a predetermined external factor.

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.

For example, in the above-described embodiment, the driver driving force Fddrv is once converted into the correcting turbine torque Ttcor and then converted into the post-correction driving force Fdcor, but this is not limitative. For example, the corrected driving force Fdcor may be directly calculated by multiplying the driver driving force Fddrv by the gear ratio change rate R. In this case, B30 in the block diagram of FIG. 2 and S30 in the flowchart of FIG. 3 are not required. In this case, although the physical items to be considered such as loss and inertia cannot be reflected in the corrected driving force Fdcor, the effect of simplifying the calculation is obtained.

In the above-described embodiment, the corrected driving force Fdcor is converted into the target turbine torque Tttgt, and the target turbine torque Tttgt is converted into the target engine torque Tetgt, but the present invention is not limited to this. For example, the target engine torque Tetgt (=(Fdcor×rw)/(γa×i×t)) may be calculated directly based on the corrected driving force Fdcor. In this case, B50 in the block diagram of FIG. 2 and S60 in the flowchart of FIG. 3 are not necessary.

Further, in the flowchart of FIG. 3 in the above embodiment, in S20, it is determined whether or not the target gear ratio γtgt is actually changed from the basic gear ratio γb to the post-change gear ratio γa. It may be determined whether or not the gear ratio change rate R is required based on the arbitration result of γtgt.

Further, in the above-described embodiment, in the flowchart of FIG. 3, when the determination in S20 is negative, the processing in S30 is not performed in S50, but the present invention is not limited to this aspect. For example, no processing is performed from the viewpoint of computational processing load, but if the determination in S20 is negative, the basic gear ratio γb and the changed gear ratio γa may be set to the same value, and the processing in S30 may be executed. Alternatively, S20 and S50 in the flow chart of FIG. 3 are not necessarily required, and the calculations after S30 may always be executed. In the case of constant calculation, when the target gear ratio γtgt cannot be changed from the basic gear ratio γb, if the basic gear ratio γb and the gear ratio after change γa are calculated as the same value, the driver driving force Fddrv and the corrected driving force are obtained. Equivalent to the force Fdcor.

Moreover, in the above-described embodiment, the continuously variable transmission 28 was illustrated as an automatic transmission to which the present invention is applied, but the present invention is not limited to this aspect. For example, in the control of a stepped transmission, if a driving force map is not set for each gear stage and a single driving force map is used, or if the value in the driving force map set for each gear stage is are the same, the present invention can also be applied to such a stepped transmission. In short, the present invention can be applied to any vehicle provided with an automatic transmission forming part of the power transmission path between the engine and the drive wheels.

It should be noted that what has been described above is just one embodiment, and the present invention can be implemented in aspects with various modifications and improvements based on the knowledge of those skilled in the art.

10: Vehicle 12: Engine 14: Drive wheel 28: Continuously variable transmission (automatic transmission)
80: Electronic control device (control device)
82: Target driving force calculation unit 84: Engine control unit

Claims (1)

A control device for a vehicle including an engine and an automatic transmission forming part of a power transmission path between the engine and driving wheels,
a target driving force calculation unit that calculates a target driving force of the vehicle based on an acceleration operation amount by a driver;
an engine control unit that calculates a target value of output torque of the engine based on the calculated target driving force and a basic gear ratio of the automatic transmission based on the calculated target driving force . ,
When the basic gear ratio is changed to the post-change gear ratio based on a predetermined external factor, the target drive force calculation unit calculates the target driving force by the ratio value of the post-change gear ratio to the basic gear ratio. It calculates the corrected driving force by correcting the target driving force,
When the basic gear ratio is changed to the post-change gear ratio, the engine control unit calculates a target value of output torque of the engine based on the calculated post-correction drive force and the post-change gear ratio. A vehicle control device characterized by:

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