JPH0712800B2 - Car constant speed running control device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a constant speed running control device for an automobile, which controls a vehicle to run while maintaining a preset target vehicle speed.

(Prior Art) A vehicle provided with a constant speed traveling device has been conventionally known, and in a vehicle provided with such a constant speed traveling device, in a predetermined driving state, a vehicle speed set by a driver, that is,
The vehicle is controlled to run at the target vehicle speed. In such a constant speed traveling control device, it is desirable to perform an appropriate gear shift operation and select an optimum gear stage so that deterioration of fuel efficiency is suppressed as much as possible and a target vehicle speed is maintained regardless of changes in traveling conditions. . JP-A-57-19317 discloses that when the vehicle speed decreases by a predetermined value from the target vehicle speed in order to prevent the vehicle speed from decreasing on an uphill in a constant-speed driving state with overdrive, the overdrive is released and the vehicle speed reaches the target vehicle speed. In a constant-speed traveling device that is restored to overdrive when it recovers, it is reset when the vehicle speed decreases and the vehicle speed is almost equalized for the purpose of reducing the discomfort given to the driver by reducing the frequency of shifting the gears. A constant-speed traveling control device is disclosed in which a timer that is set when the vehicle speed returns to the set vehicle speed is provided, and the vehicle is returned to overdrive after being delayed by the set time of the timer.

(Problems to be Solved) In the constant speed traveling device disclosed in Japanese Patent Laid-Open No. 57-19317, the timer operates once downshifted and the vehicle travels at the low speed regardless of the change in vehicle speed. However, it will continue for the set time of the timer. However, depending on the driving conditions, there are cases where the target vehicle speed is recovered relatively quickly after the downshift. In this case, the actual vehicle speed may already be significantly higher than the target vehicle speed at the time of shifting up. If shifting up in such a state, the shift shock may increase and the shift speed becomes unnecessarily high. The vehicle runs at a low speed, which is not preferable in terms of fuel consumption. Also, if you are traveling on a steep uphill, the target vehicle speed may not be reached even after the timer setting time elapses.In such a case,
Immediately after shifting up, it is necessary to shift down again. That is, there is a problem in that the constant speed traveling control device, which is configured to perform shift control using a timer as disclosed in JP-A-57-19317, cannot perform appropriate shift control.

(Means for Solving the Problem) The present invention provides a constant-speed traveling device for an automobile, which is configured in view of the above circumstances and can perform appropriate shift control in order to maintain a target vehicle speed set. It is intended to be provided.

The constant speed traveling control device of the present invention includes a throttle valve provided in the intake passage, an actuator for adjusting the opening of the throttle valve, a vehicle speed detecting means for detecting the actual vehicle speed of the vehicle, and a target for setting the target vehicle speed of the vehicle. Vehicle speed setting means, deviation detecting means for detecting a vehicle speed deviation between the actual vehicle speed and the target vehicle speed,
Based on the output signal from the deviation detection means and the driving state of the vehicle, the target driving force calculation means for calculating the target driving force required to reach the target vehicle speed, and the signal from the target driving force calculation means Throttle opening calculation means for calculating the opening of the throttle valve and feedback for controlling the throttle opening by operating the actuator so that the actual vehicle speed converges to the target vehicle speed based on the output signal from the throttle opening calculation means. And a control means.

Furthermore, in the constant speed traveling control device of the present invention, when the feedback control of the throttle opening is being performed, that is, when the constant speed traveling control is being performed, the target driving force is the high-speed side shift in use. When the maximum shaft output that can occur at a gear is exceeded, the gear shifts down and the difference between the generated shaft output and the target driving force at the low speed side gear used for traveling after the downshift, that is, margin drive at the travel gear And a shift control means for shifting up when the force exceeds a predetermined value.

In this case, the shaft output during upshift is set smaller than the shaft output during downshift.

According to the present invention, first, the vehicle speed deviation between the actual vehicle speed and the target vehicle speed is obtained, and then the deviation and the traveling state of the vehicle, that is,
The driving force necessary for the vehicle to reach the target vehicle speed is required in consideration of the road surface gradient, road surface resistance, and the like. Then, the opening of the throttle valve is determined according to the magnitude of this driving force, and the opening of the throttle valve is controlled via the actuator so that the actual vehicle speed converges to the target vehicle speed.

In this case, preferably, the constant speed traveling device of the present invention is provided with a map of the driving force required to converge to the target vehicle speed according to the target vehicle speed and the magnitude of the vehicle speed deviation, and based on this map, the basic The value of the required driving force can be obtained. Then, the throttle opening control amount is determined based on the final target driving force obtained by correcting the value of the driving force obtained from the map in consideration of the traveling state.

(Effect of the Invention) According to the present invention, the shift control during the constant speed traveling control is the driving force necessary for the vehicle to maintain the constant speed traveling, that is, the target driving force and the maximum driving force that can be generated at the traveling gear stage. That is, it is performed based on the magnitude of the maximum shaft output. In this case, the shift operation from the high-speed shift stage to the low-speed shift stage in the automatic transmission, that is, the downshift is when the target drive force exceeds the maximum shaft output at the high-speed shift stage used in the constant speed running. To be done.

After shifting down, the shift from the low-speed gear to the high-speed gear, that is, the shift-up, is performed by presetting the difference between the shaft output generated during traveling at the low-speed gear and the target driving force, that is, the margin driving force. It is supposed to be performed when it becomes larger than the value.

As described above, in the constant speed traveling control device of the present invention, the shift control is performed by focusing on the relationship between the target drive force and the shaft output of the vehicle. In this case, the target drive force and the shaft output are The change in the relationship precedes the change in the vehicle speed. As a result,
With the shift control of the present invention, it is possible to predict the vehicle speed change and perform throttle opening control, and compared with the conventional shift control that focuses on the vehicle speed change itself, the influence of changes in running conditions such as road slope and road resistance can be reduced. It can be reduced as much as possible. That is, according to the present invention, appropriate shift control can be performed.

(Description of Embodiments) Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 schematically shows a control system of a constant speed traveling device according to one embodiment of the present invention. The vehicle 1 of this example includes an engine 2 and an automatic transmission 3 connected to the engine 2, and a drive shaft 5 for driving wheels 4 is connected to the automatic transmission 3. The engine 2 is provided with an ordinary type intake system, and a throttle valve for controlling the amount of intake air into the combustion chamber is installed in the intake passage of this intake system. A throttle actuator 6 is provided to adjust the opening of the throttle valve. The vehicle 1 of this example is provided with a controller 7 preferably including a microcomputer, and the actuator 6 is operated by a command signal from the controller 7. Further, the automatic transmission 3 is equipped with a gear position sensor 8 for detecting the gear stage in operation, and a signal indicating the detected gear stage is input to the controller 7.

Further, the transmission 3 is equipped with a gear shift actuator 9 for selectively actuating a predetermined gear stage, and the actuator 9 is actuated by a signal from the controller 7. Also, the drive shaft 5
A vehicle speed sensor 10 for generating a pulse signal is attached to the vehicle, and a signal representing the vehicle speed from the vehicle speed sensor 10 is also input to the controller 7. Further, the controller 7 is provided with signals from various switches provided by the driver's operation, that is, an acceleration switch for increasing the target vehicle speed.
11, a deceleration switch 12 for reducing the target vehicle speed, a return switch 13 for restarting constant speed traveling control, a main switch 14 that is turned on when performing constant speed traveling control, a constant speed when braking operation is performed Signals are input from the brake switch 15 for canceling the traveling control and the transmission switch 16 for canceling the constant speed traveling control when the automatic transmission 3 is in neutral.

The controller 7 operates when a switch input circuit 17 that receives signals from the various switches described above, vehicle speed detection means 18 that calculates the actual vehicle speed of the vehicle, and accelerator pedal 19 are operated.
That operation amount, that is, an accelerator position detecting means 20 for detecting an accelerator opening position, a basic throttle opening calculating means 21 for calculating a basic throttle opening based on a signal from the accelerator position detecting means, and a road surface gradient are detected. Target vehicle speed setting circuit for setting a target vehicle speed based on signals from the slope detecting means 22, the switch input circuit 17 and the vehicle speed detecting means 18.
23, the target vehicle speed setting circuit 23, and a running resistance predicting means 24 for predicting the running resistance of the vehicle based on signals from the gradient detecting means 22, a vehicle based on signals from the target vehicle speed setting circuit 23 and the vehicle speed detecting means 18, The target drive force calculating means 25 for calculating the target drive force of the vehicle, the vehicle speed detecting means 18, the running resistance predicting means 24, and the target vehicle drive force calculating means 25 are used to determine an appropriate shift stage of the automatic transmission. Shift determination means 2
6 are provided respectively.

Further, the controller 7 includes a vehicle speed detecting means 18, a running resistance predicting means 24, a target driving force calculating means 25, and the shift determining means.
Based on the signal from 26, a final throttle opening calculation means 27 for calculating the final throttle opening control amount required for constant speed traveling control is provided, and the signal from this final throttle opening calculation means 27 is Output to the throttle actuator 6 via the throttle opening control means 28.

Further, the controller 7 is provided with shift control means 29 for controlling the shift stage of the automatic transmission based on the signal from the shift determination means, and the signal from this shift control means 29 is inputted to the shift actuator 6. ing.

Further, the controller 7 includes a target air-fuel ratio calculation means 30 for calculating a target air-fuel ratio based on signals from the running resistance prediction means 24 and the target driving force calculation means 25. The signal from the target air-fuel ratio calculation means 30 is provided. Is input to the fuel injection correction means 31, and the fuel injection correction means 31 outputs a command signal to the fuel injection means 32 so as to prohibit the power enrichment. The signal from the throttle opening control means 28 is also input to the slope detection means 22 and the shift determination means 26.

The control of this example will be described below.

FIG. 2 shows a main flowchart of the control of this example.

The controller 7 first initializes the system, and at the same time, the vehicle speed sensor 10, the gear position sensor 8, the accelerator pedal 19, the acceleration switch 11, the deceleration switch 12, and the return switch.
The signals from 13, the main switch 14, the brake switch 15, the transmission switch 16 and the like are read, and these signals are A / D converted. Next, the controller 7
The basic throttle opening degree calculation means 21 calculates the basic throttle opening degree (THOBJB) from the accelerator position signal A / D converted by the accelerator position detection means 20.

Next, the controller 7 executes the constant speed running control subroutine shown in FIG. 3 and FIG. 4 to calculate the throttle opening amount (THASC) required for the constant speed running control.

Then, the basic throttle opening (THOBJB) and the throttle opening amount for constant speed traveling control (THASC) are compared, and when the throttle opening amount (THASC) is large, the throttle opening amount (THASJ
C) is set to the target throttle opening (THOBJ) to perform throttle control.If the basic throttle opening (THOBJB) is large, set the basic throttle opening (THOBJB) to the target throttle opening (THOBJ). Control the throttle.

Next, the constant speed running control will be described. In FIG. 3, the controller 7 is not the main switch 14, the brake switch 15 (ON when the brake is not operated), and the transmission switch 16 Neutral. When the switch is ON, the constant speed traveling control is performed when the deceleration switch 12 or the acceleration switch 11 is not being operated.

When the vehicle satisfies the constant speed travel control start condition, the controller 7 executes the subroutine shown in FIG. 7, sets the target vehicle speed (VSOBJ), and performs the constant speed travel control.

Further, when the acceleration switch 11 is operated, the controller 7 increases the target vehicle speed (VSOBJ) by a constant value for each operation, and when the deceleration switch 12 is operated, it is a constant value for each operation. Only reduce. Further, when the return switch 13 is operated, the storage vehicle speed (MRVS) stored in the predetermined memory is set to the target vehicle speed (VSOBJ) and the constant speed traveling control is started.

Next, the controller 7 executes the subroutine shown in FIG. 6 at every timer setting time to calculate the road surface gradient.

Next, the constant speed traveling control routine described below is executed every time a predetermined time elapses. That is, when a predetermined time has passed, the controller 7 calculates the actual vehicle speed (VSR) calculated by the interrupt subroutine shown in FIG. 5 and the target vehicle speed (VSOB).
J) and then the actual vehicle speed (VSR) and target vehicle speed (VSOBJ)
Calculate the deviation (DEFVS) from and.

Then, the vehicle speed deviation (DEFVS) is a predetermined value, in this example, 15 km /
When h is exceeded, the constant speed traveling control is stopped, and the constant speed traveling control throttle opening amount (THASC), the target vehicle speed (VSOBJ) and the integral element parameter (WKINT) are initialized.

When the vehicle speed deviation (DEFVS) is within 15 km / h, the proportional element (P) for calculating the final target driving force (TROBJ) is calculated. In this case, the proportional element (P) is obtained by multiplying the vehicle speed deviation (DEFVS) by a predetermined proportional data (DP). Next, if the target vehicle speed (VSOBJ) is greater than the actual vehicle speed (VSR), the proportional element (P) is added to the target driving force (TROBJ) to obtain the actual vehicle speed (V
When SR) is larger than the target vehicle speed (VSOBJ), the current target driving force (TROBJ) is corrected by subtracting the proportional element (P) from the target driving force (TROBJ).

Next, the controller 7 calculates the integral element (I) from the integral data (DI) in order to calculate the final target driving force (TROBJ). When the target vehicle speed (VSOBJ) is higher than the actual vehicle speed (VSR) as in the proportional control, the integral element parameter
The actual vehicle speed (VSR) is the target vehicle speed by adding the integral element (I) to (WKINT)
If it is larger than (VSOBJ), the integral element parameter (WKIN
Modify the current target driving force (TROBJ) by subtracting the integral element (I) from T).

Next, since the power transmission efficiency changes depending on the oil temperature for the automatic transmission, the controller 7 calculates a correction coefficient K _O that increases the target driving force (TEOBJ) as the oil temperature is lower, and the correction coefficient K _O is calculated. This is corrected by multiplying the target driving force (TROBJ) by _O.

Next, the controller 7 uses the road surface gradient obtained from the subroutine shown in FIG. 6 and the actual vehicle speed (VSR) obtained from the subroutine shown in FIG. 5 to obtain the predicted vehicle resistance obtained from the interruption subroutine shown in FIG. (RLOAD) further corrects the target driving force (TROBJ) to obtain the final target driving force (TROBJ).
OBJ) Calculate.

Next, the controller 7 executes the shift control subroutine shown in FIG. 8 to determine the optimum gear stage (GPR) of the automatic transmission according to the current traveling state of the vehicle.

Next, the controller 7 determines the final target driving force (TROBJ), the actual vehicle speed (VSR), and the optimum shift speed (GPR) obtained by the above procedure.
The throttle opening amount for constant speed traveling control (THASC) is calculated based on In this case, the controller 7 has a map showing the relationship between the final target driving force (TROBJ), the actual vehicle speed (VSR), and the throttle opening amount for constant speed traveling control (THASC) for each shift speed. The map is used to determine the throttle opening amount (THASC) for constant speed travel control at the gear position.

The throttle opening amount for constant speed traveling control (THASC) calculated by the constant speed traveling control subroutine of FIGS. 3 and 4 is the target throttle opening degree when the predetermined condition is satisfied in the main routine of FIG. Adopted as (THOBJ),
By executing the interrupt routine shown in FIG. 10, the throttle opening is controlled through the throttle opening control means, that is, the throttle actuator 6 so that the throttle opening converges to the throttle opening amount for constant speed traveling control (THASC).

Next, a procedure for obtaining variables used in the constant speed traveling control subroutine of FIGS. 3 and 4 will be described.

FIG. 5 shows a flowchart of an interrupt routine for obtaining the actual vehicle speed (VSR) of the vehicle. When calculating the actual vehicle speed (VSR), the controller 7 reads the pulse signal from the vehicle speed sensor 10 and calculates the vehicle speed pulse period (VS
Measure T). Next, the vehicle speed pulse period (VST) is averaged to calculate the actual vehicle speed (VSR).

FIG. 6 shows a flowchart of the road surface gradient detection subroutine.

In FIG. 6, the controller 7 indicates the average vehicle speed (VSE) for the past T seconds and the average throttle opening (THE) for the past T seconds.
To calculate. Next, based on the average vehicle speed (VSE) and average throttle opening (THE), the average driving force (TRACE) during that period
And the running resistance (RROAD) in the condition that there is no grade.

Next, the controller 7 obtains the difference between the average driving force (TRACE) and the running resistance (RROAD), and calculates this value as the acceleration expected to occur per unit vehicle weight, that is, the virtual acceleration.
Set as (ACCV).

In addition, the controller 7 changes the vehicle speed (VSD) in the past T seconds.
Then, the speed change per unit time, that is,
Calculate the average acceleration (ACCE).

Then, the road gradient (RAMP) is obtained by dividing the difference between the virtual acceleration (ACCV) and the average acceleration (ACCE) by the gravitational acceleration.

Figure 7 shows the predicted resistance of the vehicle (RLOAD) and the target vehicle speed (VSOB
J) and a subroutine for obtaining the memory vehicle speed (MRVS) are shown.

In FIG. 7, the controller 7 obtains a predicted running resistance (RLOAD) using a map based on the actual vehicle speed (VSR) obtained in FIG. 5 and the road surface gradient (RAMP) obtained in FIG. Next, the initial value of the integral element parameter (WKINT) is set, and the actual vehicle speed (VSR) is stored in a predetermined storage location as the storage vehicle speed (MRVS). Further, the vehicle speed value set by the driver is stored as the target vehicle speed (VSOBJ).

Referring to FIG. 8, there is shown a flowchart of a shift control subroutine for setting a shift speed (GPR) of the automatic transmission 3.

In this routine, the controller 7 first uses the signal from the gear position sensor 8 to detect the current gear position.
(GPR) is detected. Next, the controller 7 determines the actual vehicle speed.
(VSR) and the maximum driving force (TRMA
The maximum driving force (TRMAX) at the gear is calculated from the map showing the relationship with (X). When the maximum driving force (TRMAX) of the gear is smaller than the target driving force (TROBJ), it is impossible to maintain the gear and secure the required driving force. A command signal is sent to the shift control means, that is, the shift actuator 9 so as to shift down.

Also, the maximum driving force (TRMAX) of the gear is the target driving force (TRMAX).
OBJ), the controller 7 determines that the marginal driving force (STR) at the shift speed, that is, the maximum driving force (TRMA).
The difference between X) and the target driving force (TROBJ) is calculated, and if the margin driving force exceeds a certain value, it is determined that the margin driving force is sufficient and a shift-up signal is output to the shift actuator 9. If the surplus driving force is not sufficient, the gear position is not changed.

FIG. 9 shows a flow chart of the air-fuel ratio control subroutine. In this routine, the controller 7
Is based on the target driving force (TROBJ) and actual vehicle speed (VSR).
Determine the target air-fuel ratio (AFOBJ) using the map.

Then, based on the value of the target air-fuel ratio (AFOBJ), it is determined whether or not the current operating condition satisfies the power enrichment condition. However, in the control of this example, the power enrichment is not performed when the constant speed traveling control is performed, so the power enrichment prohibition signal is sent to the fuel injection means.

As described above, in the constant speed traveling control of this example, the shift control is performed by focusing on the shaft output of the vehicle, so that the shift control is simply performed according to the vehicle speed as in the conventional case, or As compared with the type using the timer, the influence of the traveling condition is less, and therefore the appropriate shift control can be performed.

[Brief description of drawings]

FIG. 1 is a control system diagram of a constant speed traveling device according to one embodiment of the present invention, FIG. 2 is a flow chart of a main routine of control using the device of FIG. 1, and FIGS. FIG. 5 is a flowchart of a subroutine for performing constant speed traveling control according to the embodiment of the present invention, FIG. 5 is a flowchart of an interrupt routine for calculating an actual vehicle speed, and FIG. 6 is a subroutine for calculating a road gradient. Flow chart of the
FIG. 7 is a flowchart of a subroutine for calculating a predicted running resistance of the vehicle, a target vehicle speed, and a stored vehicle speed, and FIG. 8 is a flowchart of a shift control subroutine for calculating an optimum shift speed according to a running state. FIG. 10 is a flowchart of an air-fuel ratio control subroutine for prohibiting power enrichment, and FIG. 10 is a flowchart of a throttle opening control execution routine. 1 ... Vehicle, 2 ... Engine, 3 ... Automatic transmission 5 ... Drive shaft, 6 ... Throttle actuator 7 ... Controller, 8 ... Gear position sensor, 9 ... Shift actuator, 10 ... Vehicle speed sensor , 11 …… acceleration switch, 12 …… deceleration switch, 13 …… return switch, 14 …… main switch, 15 …… brake switch, 16 …… transmission switch, 19 …… accelerator pedal, 32 …… fuel injection means.

Claims (1)

[Claims] 1. A throttle valve provided in an intake passage, an actuator for adjusting an opening of the throttle valve, a vehicle speed detecting means for detecting an actual vehicle speed of the vehicle, and a target vehicle speed setting means for setting a target vehicle speed of the vehicle. A deviation detecting means for detecting a vehicle speed deviation between the actual vehicle speed and the target vehicle speed; and a target driving force necessary for making the vehicle reach the target vehicle speed based on an output signal from the deviation detecting means and the traveling state of the vehicle. Target driving force calculating means, a throttle opening calculating means for calculating the opening of the throttle valve based on a signal from the target driving force calculating means, and an actual vehicle speed based on an output signal from the throttle opening calculating means. Feedback control means for controlling the throttle opening by operating the actuator so as to converge to the vehicle speed and feedback control of the throttle opening are performed. When the target driving force exceeds the maximum shaft output that can be generated at the high speed side gear stage in use, the gear shifts down and the generated shaft output at the low speed side gear stage used for traveling after the shift down A constant speed running control device for an automobile, comprising: a shift control means for upshifting when a difference from a target driving force exceeds a predetermined value.