JPH10329585A - Driving force control device of vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To further secure the transient driving force control by performing the transient control of a driving force according to a change in a stationary target value of driving force. SOLUTION: A variation in stationary target value of driving force is obtained (S12) and, based on the value thus obtained, the time series waveform of the transient target value of driving force is determined (S13). From the waveform, the time series data of the incremental amount of target driving force is obtained (S14). Also a sum time series data is obtained by adding the time series data to the existing data (S15) and, based on the sum time series data, this incremental amount of target driving force is obtained (S16). In addition, this incremental amount of target driving force is added to the previous target driving force so as to obtain this transient target value of driving force (S26). If it is judged that this incremental amount of target driving force exceeds a specified limit (S17, S18), the exceed amount is brought over to the next control cycle. If it is judged that this transient target value of driving force exceeds the specified limit (S19, S21), the exceeded amount is brought over to the next control cycle (S26, S28).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for suitably controlling driving force such as wheel driving force in a vehicle driving system.

[0002]

2. Description of the Related Art As a control device for a vehicle drive system, a control device described in, for example, Japanese Patent Application Laid-Open No. Sho 62-110535 is known. This device obtains a target input rotation of the continuously variable transmission based on a target horsepower obtained from a driver's accelerator operation, and controls the speed of the continuously variable transmission so that the input rotation becomes the target value. The engine torque is controlled so that the target engine torque is obtained from the target horsepower and the transmission input rotation.

[0003]

However, in such a driving force control device, when the steady target driving force changes stepwise due to a change in the driving state such as a large operation of the accelerator pedal, a transient state is generated. It didn't even control it. Therefore, it is extremely rare that the transient response to the steady target driving force changed in a step-like manner is suitable for the driver and the occupant, and appropriate control is also desired for the transient response to the new target driving force. It is rare.

However, in order to realize a steady-state target driving force that changes stepwise with a required transient characteristic, even if an attempt is made to detect a steady-state change in the target driving force in a steady state, the steady-state target driving force is detected. Since the force constantly changes and does not become completely constant, it is not possible to determine the start time of the control for realizing the required transient characteristics. Problem.

[0005] Even if a steady-state change in the target driving force can be detected and the transient control of the target driving force can be performed, the steady-state control and the transient control are switched as described above. In this case, the problem that fine control cannot be performed at the expense of intermediate control between the two cannot be completely eliminated.

According to the first aspect of the present invention, the transient change of the target driving force can be performed in a step-like manner so that the transient control of the target driving force can be performed at any change of the steady target driving force. By eliminating the need to detect whether or not the target driving force is satisfied, it is also possible to perform intermediate control between the steady control and the transient control, thereby simultaneously solving the above two problems and simultaneously reducing the target driving force. An object of the present invention is to make transient control feasible.

A second object of the present invention is to make it possible to most easily obtain a time series waveform of a transient target driving force used in calculating a transient target driving force.

[0008] A third aspect of the present invention is to enable the aim of the first aspect of the present invention to be realized even when a steady-state stepwise change of the target driving force occurs continuously. .

A fourth object of the present invention is to propose a most effective method for calculating a transient target driving force.

A fifth invention according to claim 5 and a sixth invention according to claim 6 aim to propose an effective countermeasure technique when a control amount relating to a target driving force exceeds a limit. And

[0011]

To achieve these objects, a vehicle driving force control apparatus according to a first aspect of the present invention includes an engine capable of arbitrarily changing an output torque in response to a driver's accelerator operation and an automatic transmission. In the driving drive system of the vehicle to be combined, the time series waveform of the transient target driving force in the current control cycle is determined based on the steady state change of the target driving force in the driving drive system obtained from the vehicle driving state. And calculating a transient target driving force of the vehicle driving system based on the time-series waveform, and controlling the vehicle driving system so as to obtain the target driving force. It is.

[0012] A vehicle driving force control apparatus according to a second aspect of the present invention includes:
In the first invention, a time-series waveform of the transient target driving force in a current control cycle is determined from a variation width of the steady target driving force between a previous control cycle and a current control cycle. It is assumed that.

According to a third aspect of the present invention, there is provided a driving force control apparatus for a vehicle.
In the first invention or the second invention, a time series waveform of the transient target driving force in the current control cycle and a time series waveform of the transient target driving force in the control cycle up to the previous time are based on a composite waveform. In addition, the present invention is characterized in that a transient target driving force of the vehicle drive system is calculated.

According to a fourth aspect of the present invention, there is provided a driving force control apparatus for a vehicle.
In any one of the first to third inventions described above, the time series data of the target driving force increase / decrease between adjacent control cycles is obtained from the time series waveform of the transient target driving force in the current control cycle or the composite waveform. The current target driving force increase / decrease is obtained based on data obtained by adding this time series data to the time series data of the total sum of the target driving force increase / decrease so far. Is added to the previous transient target driving force to calculate the current transient target driving force.

A vehicle driving force control apparatus according to a fifth aspect of the present invention
In the fourth aspect, when the current target driving force increase / decrease is out of the limit range, the current target drive force increase / decrease is limited to the limit value of the limit range, and the difference between the current target drive force increase / decrease amount and the limit value is determined. Only the next increase / decrease in the target driving force is corrected, and the difference is carried over to the next control.

A vehicle driving force control apparatus according to a sixth aspect of the present invention
In the fourth or fifth aspect of the present invention, when the present transient target driving force is out of the limit range, the present transient target drive force is limited to the limit value of the limit range, and the present transient target drive force is limited. The present invention is characterized in that the next target driving force increase / decrease is corrected by the difference between the limit values for the driving force and the difference is carried over to the next control.

[0017]

The driving force control apparatus according to the first aspect of the present invention provides a driving drive system for a vehicle which is a combination of an engine capable of arbitrarily changing the output torque in response to a driver's accelerator operation and an automatic transmission as follows. To control the driving force. That is, a steady-state target driving force of the traveling drive system is obtained from the vehicle driving state, and a time-series waveform of the transient target driving force in the current control cycle is determined based on the degree of change of the steady target driving force. . Then, based on the time series waveform of the transient target driving force, a transient target driving force of the vehicle drive system is calculated,
The vehicle drive system is controlled so as to obtain the target drive force.

According to the structure of the first aspect of the present invention for controlling the driving force of the vehicle as described above, the transient control of the target driving force can be performed at any change of the steady target driving force. It is not necessary to detect whether the change in the target driving force is step-shaped, and it is also possible to perform intermediate control between the steady control and the transient control. It is possible to eliminate the problem that the transient control of the target driving force could not be performed due to the difficulty in detecting the target driving force, and to perform the fine-grained transient control because the intermediate control between the steady control and the transient control could not be performed. The problem that control cannot be performed can be solved.

In the second invention, the time series waveform of the transient target driving force in the current control cycle is determined from the steady-state change width of the target driving force between the previous control cycle and the current control cycle. A time-series waveform of a transient target driving force used in calculating a typical target driving force can be obtained most easily, which is extremely advantageous in cost.

In the third invention, a time series waveform of the transient target driving force in the current control cycle and a time series waveform of the transient target driving force in the control cycle up to the previous time are obtained. Since the transient target driving force of the vehicle drive system is calculated, even if the steady-state stepwise change of the target driving force occurs continuously, the operation and effect of the first aspect of the present invention can be reliably achieved. be able to.

In the fourth invention, the time series data of the increase / decrease of the target driving force between adjacent control cycles is obtained from the time series waveform of the transient target driving force in the current control cycle or the above-mentioned combined waveform. The current target driving force increase / decrease is obtained based on data obtained by adding the time series data to the time series data of the total sum of the target driving force increase / decrease so far. Since this transitional target driving force is calculated by adding the

In the fifth invention, when the current target drive force increase / decrease is out of the limit range, the current target drive force increase / decrease is limited to the limit value of the limit range, and the current target drive force increase / decrease is not limited. Since the next target drive force increase / decrease is corrected by the value difference and the above difference is carried over to the next control, even when the target drive force increase / decrease exceeds the limit, the excess is carried over to the next control. , Control accuracy can be improved.

In the sixth invention, when the current transient target driving force is out of the limit range, the current transient target driving force is limited to the limit value of the limit range and the current transient target drive force is limited. Since the next target drive force increase / decrease is corrected by the difference of the limit value with respect to the force and the difference is carried forward to the next control, even when the target drive force exceeds the limit, the carryover to the next control for the excess is performed. Thus, control accuracy can be improved.

[0024]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a flowchart of a control program executed by the vehicle driving force control device according to one embodiment of the present invention. In the present embodiment, an engine as an engine mounted on a vehicle has a throttle valve for changing its output torque that is not mechanically connected to an accelerator pedal operated by a driver. Separately, the opening degree is controlled electronically so that the engine torque can be arbitrarily changed.

The automatic transmission which forms a vehicle drive system in combination with the engine is preferably a continuously variable transmission such as a V-belt type continuously variable transmission whose transmission ratio is continuously changed or a toroidal type continuously variable transmission. The use of a stepped transmission is convenient for control.

The processing of FIG. 1 will be described below. In step 11, the required output of the axle is calculated from the accelerator pedal depression amount, the vehicle speed, and road information such as road gradient, and this is calculated as the steady driving force target. Value (Driving force steady target value)
And Next, in step 12, the previous driving force steady-state target value is subtracted from the current driving force steady-state target value,
The amount of change (the amount of change in the steady-state driving force target value) of the steady-state driving force value during one control cycle is determined.

Next, in step 13, a time series waveform (transient characteristic time series waveform) of a transient driving force target value (driving force transient target value) is calculated from the driving force steady target value change amount.
It is determined using a predetermined logic. Here, the transient characteristic time series waveform is a time series waveform of the driving force steady-state target value shown in FIG.
In the following, a description will be given of a case as shown by a dashed line a.
The response waveform is set so that the driving force falls within the current driving force steady-state target value as quickly as possible within a range in which the transient control of the driving force does not become oscillatory.

In step 14, the transient characteristic time series
From the waveform b, adjacent control cycles indicated by arrows in FIG.
As shown in FIG.
Create such time series data. In the next step 15,
The time series data of the increase / decrease of the target driving force is
Increase in target driving force in addition to total time series data
Update the decremented sum time series data. Update like this
The time series data of the target driving force increase / decrease this time is shown in FIG.
(A) shows a broken line a₁, A_TwoDriving force steady target value
Two times approach each other and step up
Explaining this, the first rise of the driving force steady-state target value a ₁
Time series waveform b of the driving force transient target value corresponding to₁And the drive
The second rise of the force steady-state target value a_TwoDriving force transient corresponding to
Time series waveform of target value b_TwoFigure 3 (a)
Solid line b_ThreeThe solid waveform shown in FIG.
It is very much needed.

In step 16, the updated target drive
Power increase / decrease total time series data b (b _Three) From this eye
The target drive force increase / decrease is extracted, and in steps 17 and 18,
The target drive force increase / decrease that is extracted this time is the maximum target drive force.
Is greater than the amount of change (maximum target drive force increase), or
Is smaller than the target driving force minimum change amount (target driving force maximum reduction amount).
Is too small or the maximum change in these target driving forces?
And the value between the target driving force minimum change amount
Check if

If the current target driving force increase / decrease is greater than the maximum target driving force change (the maximum target driving force increase),
In step 19, the next target drive force increase / decrease is increased and corrected by the current target drive force increase / decrease relative to the target drive maximum increase amount, and the excess is carried over to the next control cycle. Fig. 4
As described above, the transient characteristic time-series waveform of the driving force steady-state target value shown by the broken line a in FIG. As shown in FIG. 4B, the next target drive power increase / decrease is represented by α ′ by the excess amount α of the current target drive power increase / decrease with respect to the target drive power maximum increase amount as shown in FIG. from being raised so as, in the next control cycle so that the target driving force increment or decrement is determined based on the transient characteristic time-series waveform shown by the solid line b ₄ in the diagram (a).
In step 20, the current target driving force increase / decrease is limited to the target driving force maximum increase amount, and the excessive amount α in FIG. 4B is excluded, and this excessive amount α is used in the next control cycle as described above. carry forward.

When the current target drive force increase / decrease is smaller than the target drive force minimum change amount (target drive force maximum decrease amount),
In step 21, the next target drive force increase / decrease is increased and corrected by the current target drive force increase / decrease relative to the target drive force minimum change amount, and the underestimate is carried over to the next control cycle. In step 22, the current target driving force increase / decrease is limited to the target driving force minimum change amount.

If the current target driving force increase / decrease falls within the value between the target driving force maximum change amount and the target driving force minimum change amount, steps 19 to 22 are skipped and the current target drive force increase / decrease amount is calculated. It is used as it is without any restriction, and of course, the carryover to the next control cycle is not performed.

In step 23, the current target drive force increase / decrease determined as described above is added to the previous target drive force to obtain the current drive force transient target value. The driving force transient target value is in an excessive state exceeding the maximum value of the target driving force, in an excessively small state less than the minimum value of the target driving force, or within a value between the maximum value of the target driving force and the minimum value of the target driving force. Check if you are.

If the current driving force transient target value is larger than the target driving force maximum value, in step 26, the next target driving force increase / decrease amount is increased by the current driving force transient target value with respect to the target driving force maximum value. Is raised, and the excess is carried over to the next control cycle. This carry-over will be described with reference to FIG. 5. The transient characteristic time-series waveform is different from the time-series waveform of the driving force steady-state target value indicated by the broken line a in FIG. ), The next target driving force as shown by β ′ in FIG. 7B is the excess β of the current driving force transient target value with respect to the target driving force maximum value. since the force increment or decrement is raised, in the next control cycle so that the target driving force increment or decrement is determined based on the transient characteristic time-series waveform shown by the solid line b ₅ in the diagram (a). In step 27, the current driving force transient target value is limited to the maximum target driving force as shown by the solid line in FIG. 5A, and the excess β in FIG. Is carried over to the next control cycle.

If the current driving force transient target value is smaller than the target driving force minimum value, in step 28, the next target driving force increase / decrease amount is reduced by the current driving force transient target value with respect to the target driving force minimum value. Is raised and corrected to carry over the underestimation to the next control cycle, and then in step 29, the current driving force transient target value is limited to the target driving force minimum value.

When the current driving force transient target value falls within a value between the target driving force maximum value and the target driving force minimum value,
Steps 26 to 29 are skipped, the current drive force transient target value is used without any limitation, and the above-described carryover to the next control cycle is not performed.

Although not shown in the drawings, the torque control via the throttle opening of the engine and the engine speed via the shift control of the automatic transmission are performed so that the current drive force transient target value obtained above is achieved. The control is performed to set the driving force of the vehicle traveling system to the above-mentioned transient target value.

Finally, in step 30 of FIG. 1, the current target drive force increase / decrease is deleted from the target drive force increase / decrease total time-series data, the control cycle is advanced only once, and the above cycle is repeated.

According to the above driving force control, a steady target driving force of the traveling drive system is obtained from the vehicle driving state (step 11), and the amount of change of the steady target driving force during the control cycle (step 12). ), A time series waveform of the transient target driving force in the current control cycle (see FIG. 2) or a composite waveform of these time series waveforms (see FIG. 3) is determined (step 13). The time series data for the increase or decrease in the target driving force during the control cycle is obtained (step 14), and the time series data is added to the time series data of the total sum of the increase or decrease in the target driving force so far (step 14). 15), the current target drive force increase / decrease is obtained (step 16), and the current target drive force increase / decrease is added to the previous transient target drive force to obtain the current transient target drive force. From the fact that out (step 23),
The transient control of the target driving force can be performed at any time of the steady change of the target driving force.Therefore, it is not necessary to detect whether or not the steady change of the target driving force is step-like. Intermediate control of transient control is also possible, and the problem that transient control of target driving force could not be performed because it was difficult to detect whether or not the change in the target driving force in a steady state was step-like. It is also possible to solve the problem that fine transient control cannot be performed due to the inability to perform intermediate control between the steady control and the transient control.

In particular, in order to determine the time series waveform of the transient target driving force in the current control cycle from the steady-state change amount of the target driving force between the previous control cycle and the current control cycle, The time series waveform of the transient target driving force used in calculating the driving force can be obtained most easily, which is very advantageous in cost.

Further, based on a composite waveform of the time series waveform of the transient target driving force in the current control cycle and the time series waveform of the transient target driving force in the previous control cycle, the vehicle drive system In order to calculate the transient target driving force, the above-described operation and effect can be reliably achieved even when the stepwise change of the steady target driving force occurs continuously.

In addition, if it is determined in steps 17 and 18 that the current target drive force increase / decrease is out of the limit range, the current target drive force increase / decrease is limited to the limit value of the limit range as described above with reference to FIG. (Steps 20 and 22), the next target drive power increase / decrease is corrected (α ') by the difference α between the limit value and the current target drive power increase / decrease, and the difference is carried over to the next control (step 19). Therefore, even when the target driving force increase / decrease exceeds the limit, the control accuracy can be improved by carrying over to the next control corresponding to the excess.

Further, when it is determined in steps 24 and 25 that the current transient target driving force is out of the limit range, the current transient target driving force is set to the limit value of the limit range as described above with reference to FIG. (Steps 27 and 29) and the difference β between the limit value and the current transient target driving force.
Only the next increase / decrease in the target driving force is corrected (β ′), and the difference is carried over to the next control (steps 26 and 28). Therefore, even when the target driving force exceeds the limit, the next Carrying over the control can increase the precision of the control.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a control program executed by a vehicle driving force control device according to an embodiment of the present invention.

FIG. 2A is a time chart illustrating a time-series waveform of a driving force transient target value determined in the embodiment together with a time-series waveform of a driving force steady-state target value, and FIG. It is a time chart which shows the time series data of the drive power increase / decrease calculated | required from the time series waveform of the transient target value.

FIG. 3A is a time chart showing a time-series waveform of a driving force transient target value determined in the embodiment, in a case where the driving force steady target values approach each other and rise twice in a step-like manner. (B) is a time chart showing time-series data of the increase and decrease of the driving force obtained from the time-series waveform of the driving force transient target value.

FIG. 4A is a time chart showing a time-series waveform of a driving force transient target value determined in the embodiment, when a driving force increase / decrease exceeds a maximum increase amount, and FIG.
5 is a time chart showing time-series data of an increase / decrease in driving force obtained from a time-series waveform of the driving force transient target value.

FIG. 5A is a time chart showing a time-series waveform of a driving force transient target value determined in the embodiment, when the driving force transient target value exceeds a maximum value, and FIG.
5 is a time chart showing time-series data of an increase / decrease in driving force obtained from a time-series waveform of the driving force transient target value.

[Explanation of symbols]

a Time series waveform of steady driving force target value a ₁ Time series waveform of steady driving force target value a ₂ Time series waveform of steady driving force target value b Time series waveform of driving force transient target value b ₁ Time series waveform of driving force transient target value time-series waveform b ₅ driving force of the driving force transitional target value in the case of composite waveform b ₄ driving force increment or decrement of the time-series waveform b ₃ driving force transitional target value of the time-series waveform b ₂ driving force transitional target value exceeds the limit Time series waveform of the driving force transient target value when the transient target value exceeds the limit

Claims (6)

[Claims] 1. A traveling drive system for a vehicle, which is a combination of an engine capable of arbitrarily changing an output torque in response to a driver's accelerator operation and an automatic transmission, comprising: The time series waveform of the transient target driving force in the current control cycle is determined based on the degree of change of the target driving force, and the transient target driving force of the vehicle drive system is determined based on the time series waveform. A driving force control device for a vehicle, wherein the driving force is calculated and the vehicle driving system is controlled so as to obtain the target driving force. 2. The system according to claim 1, wherein a time-series waveform of the transient target driving force in a current control cycle is determined from a change width of the steady target driving force between a previous control cycle and a current control cycle. A driving force control device for a vehicle, comprising: 3. A composite waveform of a time series waveform of a transient target driving force in a current control cycle and a time series waveform of a transient target driving force in a control cycle up to the previous time. A driving force control device for a vehicle, characterized in that it is configured to calculate a transient target driving force of a vehicle driving system. 4. A method according to claim 1, wherein a time series waveform of the transient target driving force in the current control cycle or the combined waveform is used to increase or decrease the target driving force between adjacent control cycles. Of the current target driving force is obtained based on data obtained by adding the time series data to the time series data of the total sum of the target driving force fluctuations up to now, and the current target driving force fluctuation is obtained. A driving force control device for a vehicle, wherein a driving force increase / decrease amount is added to a previous transient target driving force to calculate a current transient target driving force. 5. The method according to claim 4, wherein when the current target driving force increase / decrease is out of the limit range, the current target driving force increase / decrease is limited to a limit value of the limit range, and the current target driving force increase / decrease is not limited. A driving force control apparatus for a vehicle, wherein the difference in the next target driving force is corrected by the difference between the limit values, and the difference is carried over to the next control. 6. The method according to claim 4, wherein when the current transient target driving force is out of the limit range, the current transient target driving force is limited to a limit value of the limit range.
A driving force control device for a vehicle, wherein the next target driving force increase / decrease is corrected by a difference between a limit value and a current transient target driving force, and the difference is carried over to the next control.