JPS62231825A - Constant speed travel control device for automobile - Google Patents

Abstract

PURPOSE:To maintain a target vehicle speed by providing a speed change control which carries out down shift when throttle opening is below a defined value and an actual vehicle speed becomes above a target value. CONSTITUTION:A controller 7 has a final throttle opening operating means 27 and a speed change control means 29 for operating a throttle opening controlled variable based on signals from a vehicle speed detecting means 18, a target driving force operating means 25, and a speed change judging means 26. In a constant speed travel control, when actual vehicle speed becomes above the target vehicle speed as when traveling down a slope, the speed change control means 29 shifts down an automatic transmission 3. Thereby, since the effect of engine brake is higher in the low speed side speed change stage than in the high speed side speed change stage, the increasing tendency of vehicle speed can be effectively suppressed. Accordingly, the constant speed travel control can be continuously carried out while maintaining the target vehicle speed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a constant speed cruise control device for an automobile that controls the vehicle to travel while maintaining a preset target vehicle speed.

(Prior Art) Vehicles equipped with a constant speed traveling device have been known for a long time. In a vehicle equipped with such a constant speed traveling device, in a predetermined driving state, the vehicle speed set by the driver, that is,
The vehicle is controlled to run at the target vehicle speed. In such a constant speed cruise control device, it is desirable to select an optimal gear position so as to maintain a target vehicle speed regardless of changes in traveling conditions by performing a gear change operation as appropriate. Japanese Patent Publication No. 57-193
Publication No. 17 discloses a constant speed driving control device that includes speed change control for an automatic transmission. In this device, the vehicle speed is adjusted to prevent the vehicle speed from decreasing on an uphill slope in a constant speed driving state with overdrive. Overdrive is released when the target vehicle speed decreases by a predetermined value, and returns to overdrive when the vehicle speed recovers to the target vehicle speed. In the disclosed device, a timer is used to reduce the frequency of shifting gears, thereby reducing the discomfort felt by the driver.

(Problems to be Solved) The constant speed traveling device disclosed in the above-mentioned Japanese Patent Application Laid-open No. 57-19317 solves the problem in driving conditions where the vehicle speed decreases, such as when the vehicle travels uphill. However, it does not take into consideration driving conditions where the vehicle speed increases, such as when the vehicle is traveling downhill, and therefore it cannot be used properly in such cases. It is not possible to perform constant speed driving control.

(Means for Solving the Problems) The present invention was constructed in view of the above circumstances, and particularly performs appropriate gear change control in driving conditions where the vehicle speed tends to increase, such as when driving on a downhill slope. It is an object of the present invention to provide a constant speed traveling device for an automobile that can maintain a target vehicle speed set by the vehicle speed.

The constant speed cruise control device of the present invention includes a throttle valve provided in an intake passage, an actuator that adjusts the opening degree of the throttle valve, a vehicle speed detecting means that detects the actual vehicle speed of the vehicle, and a target vehicle speed that sets the target vehicle speed of the vehicle. a vehicle speed setting means; a deviation detection means for detecting a vehicle speed deviation between the actual vehicle speed and the target vehicle speed;
a throttle opening calculation means for calculating the opening of the throttle valve based on the output signal from the deviation detection means; and a throttle opening calculation means for calculating the opening of the throttle valve based on the output signal from the throttle opening calculation means; The throttle valve is equipped with feedback control means for controlling the throttle opening by operating the throttle valve.

Furthermore, in the present invention, constant speed driving control is performed by throttle opening in combination with automatic transmission speed change control, and in driving conditions where it is difficult to maintain the target vehicle speed only by throttle opening control. The vehicle speed is controlled by appropriately changing the speed of the automatic transmission.

That is, in the constant speed cruise control device of the present invention, when feedback control of the throttle opening degree is performed, that is, when constant speed cruise control is performed, the throttle opening degree is equal to or less than a predetermined value, The vehicle also includes a shift control means for downshifting when the actual vehicle speed exceeds the target vehicle speed.

In a preferred embodiment of the present invention, first, the vehicle speed deviation between the actual vehicle speed and the target vehicle speed is determined, and then the vehicle is adjusted to the target vehicle speed by taking into consideration this deviation and the driving condition of the vehicle, that is, the slope of the road surface, road surface resistance, etc. The driving force required to reach this point is required. Then, the opening degree of the throttle valve is determined according to the magnitude of this driving force, and the opening degree 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 The required driving force value can be obtained. The throttle opening control amount is determined based on the final target driving force obtained by correcting the driving force value obtained from the map in consideration of the driving condition.

(Effects of the Invention) In constant speed driving control, for example, when driving downhill, even if the throttle opening is reduced to suppress the generated output, the actual vehicle speed may exceed the target vehicle speed.

In the present invention, this tendency of increasing vehicle speed cannot be suppressed,
Therefore, with only feedback control of throttle opening,
If it is difficult to converge to the target vehicle speed, the automatic transmission is downshifted. In this way, the engine braking effect is greater in the low speed gear than in the high speed gear, so it is possible to effectively suppress the tendency for the vehicle speed to increase. Conventionally, when the actual vehicle speed deviates significantly from the target vehicle speed under the above-mentioned driving conditions, constant speed driving control was stopped, but as in the present invention, speed change control is performed. As a result, even in the above case, the target vehicle speed can be maintained, and constant speed driving control can be continued. That is, according to the present invention, the range of application of constant speed cruise control can be expanded.

(Description of Examples) Examples of the present invention will be described below with reference to the drawings.

FIG. 1 schematically shows a control system of a constant speed traveling device according to an 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 equipped with a conventional type of intake system, and a throttle valve for controlling the amount of intake air into the combustion chamber is installed in an intake passage of this intake system. A throttle actuator 6 is provided to adjust the opening degree of this throttle valve. The vehicle 1 of this example includes a controller 7 preferably including a micro combi coater, and the actuator 6 is actuated by a command signal from the controller 7. Further, the automatic transmission 3 is equipped with a gear position sensor 8 that detects the gear position in operation, and a signal indicating the detected gear position is manually input to the controller 7.

Further, the transmission 3 is equipped with a shift actuator 9 for selectively operating a predetermined gear stage, and this actuator 9 is adapted to be operated by a signal from the controller 7. In addition, the drive shaft 5
A vehicle speed sensor 10 that generates a pulse signal is attached to the controller 7, and a signal representing the vehicle speed from this vehicle speed sensor 10 is also input to the controller 7. Furthermore, the controller 7 receives signals from various switches given by the driver's operations, namely an acceleration switch 11 for increasing the target vehicle speed, a deceleration switch 12 for decreasing the target vehicle speed, and a return signal for restarting constant speed driving control. switch 13, main switch 14 that is turned on when performing constant speed driving control;
Signals are sent from the brake switch 15 for canceling the constant speed cruise control when a braking operation is performed, and from the transmission switch 16 for canceling the constant speed cruise control when the automatic transmission 3 is in neutral. is input.

The controller 7 includes a switch input circuit 17 that receives signals from the various switches described above, a vehicle speed detection means 18 that calculates the actual speed of the vehicle, and an operation amount when the accelerator pedal 19 is operated, that is, the accelerator opening position. an accelerator position detecting means 20 for detecting the accelerator position, a basic throttle opening calculating means 21 for calculating the basic throttle opening based on the signal from the accelerator position detecting means, a slope detecting means 22 for detecting the slope of the road surface, and the above-mentioned switch input circuit. a target vehicle speed setting circuit 23 that sets a target vehicle speed based on signals from the vehicle speed detection means 17 and the vehicle speed detection means 18; a running resistance that predicts the running resistance of the vehicle based on signals from the target vehicle speed setting circuit 23 and the slope detection means 22; A target driving force calculating means 25 that calculates a target driving force of the vehicle based on signals from the predicting means 24, the target vehicle speed setting circuit 23, and the vehicle speed detecting means 18, the vehicle speed detecting means 18, the running resistance predicting means 24, and the target vehicle. Each of the automatic transmissions includes a shift determination means 26 that determines an appropriate gear stage of the automatic transmission based on a signal from the driving force calculation means 25.

Further, the controller 7 determines the final throttle opening control amount necessary for constant speed driving control based on signals from the vehicle speed detecting means 18, the traveling resistance predicting means 24, the target driving force calculating means 25, and the shift determining means 26. The final throttle opening calculation means 27 is provided, and a signal from the final throttle opening calculation means 27 is outputted to the throttle actuator 6 via the throttle opening control means 28.

Further, the controller 7 includes a shift control means 29 that controls the gear position of the automatic transmission based on the signal from the shift determination means, and the signal from the shift control means 29 is manually inputted to the shift actuator 9. ing.

The controller 7 also includes a target air-fuel ratio calculation means 30 that calculates a target air-fuel ratio based on the signals from the running resistance prediction means 24 and the target driving force calculation means 25. is the fuel injection correction means 31
Under manual control, the fuel injection correction means 31 outputs a command signal to the fuel injection means 32 to inject a predetermined amount of fuel. Further, the signal from the throttle opening control means 28 is also manually input to the slope detection means 22 and the shift determination means 26.

The control of this example will be explained below.

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

The controller 7 first initializes the system and switches the vehicle speed sensor 10, gear position sensor 8, accelerator pedal 19, acceleration switch 11, deceleration switch 12, return switch 13, main switch 14, brake switch 15, transmission switch 16, etc. , and A/D converts these signals. next,
The controller 7 converts the accelerator position signal A/D converted by the accelerator position detection means 20 into a basic throttle opening degree (THOB) using the basic throttle opening calculation means 21.
JB) is calculated.

Next, the controller 7 executes the constant speed cruise control subroutine shown in FIGS. 3 and 4 to calculate the throttle opening degree i (THASC) required for the constant speed cruise control.

Then, the basic throttle opening (THOBJB) and the throttle opening for constant speed cruise control (THASC) are compared, and if the throttle opening 1 (THASC) is large, the throttle opening (THASC) is changed to the target throttle opening. If the basic throttle opening (T)IOBJB) is large, set the basic throttle opening (THOBJB) to the target throttle opening (T)IOBJ), Perform throttle control.

Next 1. To explain the constant speed running control, in FIG. 3, the controller 7 turns on the main switch 14, the brake switch 15 (on when the prekinesis is activated), and the transmission switch 16 when the gear is in any gear other than neutral. ) is turned on and the deceleration switch 12 or the acceleration switch 11 is not being operated, constant speed driving control is performed.

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

Furthermore, when the acceleration switch 11 is operated, the controller 7 increases the target vehicle speed (VSOBJ) by a fixed value each time the acceleration switch 11 is operated, and when the deceleration switch 12 is operated, the controller 7 increases the target vehicle speed (VSOBJ) by a fixed value every time the acceleration switch 11 is operated. decrease only. Furthermore, when the return switch 13 is operated, the memorized vehicle speed (MRVS) stored in a predetermined memory is set to the target vehicle speed (VSOBJ) and constant speed running control is started.

Next, the controller 7 calculates the road surface slope by executing the subroutine shown in FIG. 6 at each timer setting time.

Next, a constant speed running control routine, which will be described below, is executed every predetermined time period. That is, when a predetermined period of time has elapsed, the controller 7 compares the actual vehicle speed (VSR) calculated by the interrupt execution subroutine shown in FIG. 5 with the target vehicle speed (VSOBJ), and then compares the actual vehicle speed (VSR) with the target vehicle speed (VSOBJ). The deviation (t)BFVS) from the target vehicle speed (VSOBJ) is calculated.

Then, the vehicle speed deviation (FVS) is a predetermined value, in this example,
If the speed exceeds 15 km/h, constant speed driving control is stopped and the throttle opening for constant speed driving control is changed! (THA
SC), the target vehicle speed (VSOBJ) and the integral element parameter (WKINT) are initialized.

If the vehicle speed deviation (DIEFVS) is within 15 km/h, a proportional element (P) for calculating the final target driving force (TROBJ) is calculated. In this case the proportional element (P)
is the predetermined proportional data (O
P). Next, when the target vehicle speed (VSOBJ) is greater than the actual vehicle speed (VSR), a proportional element (P) is added to the target driving force (TROBJ), and when the actual vehicle speed (VSR) is greater than the target vehicle speed (VSOBJ), To obtain the current target driving force (TROBJ), the proportional element (P) is subtracted from the target driving force (TROBJ).
BJ) is corrected.

Next, the controller 7 outputs the final target driving force (TROBJ
) from the integral data (DI) to calculate the integral element (
1) Calculate. Similarly to the above proportional control, if the target vehicle speed (VSOBJ) is greater than the actual vehicle speed (VSR), an integral element (+> is added to the integral element parameter (WKINT), and the actual vehicle speed (VSR) is set to the target vehicle speed (VSOBJ).
J), the integral element parameter ((νK
The current target driving force (TROBJ) is corrected by subtracting the integral element (1) from the current target driving force (TROBJ).

Next, the controller 7 uses the road surface slope obtained from the subroutine shown in FIG. 6 and the actual vehicle speed (VSR) obtained from the subroutine shown in FIG. 5 to calculate the predicted vehicle resistance obtained from the interrupt subroutine shown in FIG. (RLOA
D) The target driving force (TROBJ) is further corrected to calculate the final target driving force (TROBJ).

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

Next, the controller 7 sets the constant speed cruise control throttle opening 1 (THASC) based on the final target driving force (TROBJ), actual vehicle speed (VSR), and optimum gear position (GPR) obtained in the above-described procedure. calculate. In this case, the controller 7 controls the final target driving force (TROBJ), the actual vehicle speed (vSR), and the throttle opening degree 1 for constant speed driving control.
(TIIASC) A map is provided for each gear position, and this map is used to determine the throttle opening for constant speed driving control (1(T)IASC) at the relevant gear position.
Determine.

Throttle opening amount for constant speed driving control (THASC) calculated by the constant speed driving control subroutine shown in FIGS.
) is the target throttle opening (THOBJ) if the predetermined conditions are satisfied in the main routine of Figure 2.
The throttle opening control means, that is, the throttle actuator unique 6, controls the throttle opening so that the throttle opening converges to throttle opening 1 for constant speed cruise control (THASC) by executing the interrupt routine shown in FIG. Control takes place.

Next, a procedure for determining variables used in the constant speed cruise control subroutines shown in FIGS. 3 and 4 will be explained.

FIG. 5 shows a flowchart of an interrupt routine for determining the actual vehicle speed (VSR) of the vehicle. In calculating the actual vehicle speed (VSR), the controller 7
The pulse signal from the vehicle speed sensor 10 is read and the vehicle speed pulse period (VST) is measured. 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 slope detection subroutine.

In FIG. 6, the controller 7 calculates the average vehicle speed (VSE) for the past T seconds and the average throttle opening (THAR) for the past T seconds. Next, calculate the average vehicle speed (VS
E) and the average throttle opening (THAR), the average driving force (TRACE) during that time and the running resistance (RROAD) in a state where there is no slope are determined.

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

The controller 7 also controls the vehicle speed change (vS
D) is calculated, and the speed change per unit time, that is, the average acceleration (ACCB) is determined.

Then, virtual acceleration (ACCV) and average acceleration (ACC
E) is divided by the gravitational acceleration to calculate the road surface slope (RAλiP
).

FIG. 7 shows a subroutine for determining the predicted vehicle resistance (RLOAD), target vehicle speed (VSOBJ), and memorized vehicle speed (MRVS).

In FIG. 7, the controller 7 stores the actual vehicle speed (VSR) obtained in FIG. 5 and the road surface gradient (RAM) obtained in FIG.
Based on P), the predicted running resistance (RLOA) is calculated using a map.
Find D). Next, the integral element parameter (WKIN
In addition to setting the initial value of T), the actual vehicle speed (VSR) is stored in a predetermined storage location as a memorized vehicle speed (MRVS). In addition, the vehicle speed value set by the driver is changed to the target vehicle speed (
VSOBJ).

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

In this routine, the controller 7 first detects the current gear position (GPR) based on a signal from the gear position sensor 8. Next, the actual vehicle speed (VSR)
and the target vehicle speed (VSOBJ), and determine the actual vehicle speed (V
SR) exceeds the target vehicle speed (VSOBJ), the throttle opening degree is determined. If the throttle opening is below a predetermined value close to full throttle, the controller 7 outputs a downshift signal to the speed change actuator 9. Furthermore, when the actual vehicle speed (VSR) is smaller than the target vehicle speed (VSOBJ), the controller 7 calculates the relationship between the actual vehicle speed (VSR) and the maximum driving force (TRMAX) that can be exerted at each gear (GPR). The maximum driving force (TRMAX) at the relevant gear stage is determined from the map shown. Then, the maximum driving force (TRMAX
) is smaller than the target driving force (TROBJ), it is impossible to maintain the gear position and secure the required driving force. It sends a command signal to downshift.

Further, when the maximum driving force (TRMAX) of the gear position is larger than the target driving force (TROBJ), the controller 7 calculates the margin driving force (STR) at that gear position, that is, the maximum driving force (TRMAX) and the target drive force. Power (TR
OBJ), 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 speed change actuator 9.

Note that if the extra driving force is not sufficient, the gear position is not changed.

As described above, in the constant speed driving control of this example, even if the throttle opening is controlled to a state close to full open, a downshift is performed in a driving state where the vehicle speed exceeds the target vehicle speed (VSOBJ). There is. This makes it possible to effectively suppress the tendency of the vehicle to accelerate by utilizing the engine braking effect of the low speed gear, which is greater than that of the high speed gear. Stable constant speed driving control can be performed even when the vehicle is running at a constant speed.

In addition, in the above driving state, it is also possible to pay attention to changes in vehicle acceleration and perform downshift control to suppress the vehicle speed.

In this case, for example, a change in vehicle speed is detected every 5QQms, and if the acceleration of the vehicle exceeds a predetermined value and the actual vehicle speed (VSR
) The downshift may be performed when the vehicle speed is higher than the target vehicle speed (VSOBJ).

[Brief explanation of drawings]

FIG. 1 is a control system diagram of a constant speed traveling device according to an embodiment of the present invention, FIG. 2 is a flowchart of a main routine of control using the device shown in FIG. 1, and FIGS. 3 and 4 are A flowchart of a subroutine for performing constant speed driving control according to an embodiment of the present invention, FIG. 5 is a flowchart of an interrupt routine for calculating the actual vehicle speed, and FIG. 6 is a subroutine for calculating the road surface gradient. flow chart,
FIG. 7 is a flowchart of a subroutine for calculating the vehicle's predicted running resistance, target vehicle speed, and memorized vehicle speed. FIG. The figure is a flowchart of the throttle opening control execution routine. 1...Vehicle, 2...Engine, 3...
... Automatic transmission 5 ... MIX dynamic L 6 ...
...Throttle actuator 7...Controller, -...Gear position sensor, 9...Speed change 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. Fig. 2 Main routine Subroutine Subroutine Fig. 6 Subroutine Fig. 7 Subroutine

Claims (1)

[Claims] a throttle valve provided in an intake passage; an actuator for adjusting the opening degree of the throttle valve; a vehicle speed detection means for detecting the actual vehicle speed of the vehicle; a target vehicle speed setting means for setting a target vehicle speed of the vehicle; a deviation detection means for detecting a vehicle speed deviation from a target vehicle speed; a throttle opening calculation means for calculating the opening of the throttle valve based on an output signal from the deviation detection means; and an output signal from the throttle opening calculation means. feedback control means for controlling the throttle opening by operating the actuator so that the actual vehicle speed converges to the target vehicle speed based on the feedback control means; What is claimed is: 1. A constant speed driving control device for a motor vehicle, comprising a shift control means for downshifting when the actual vehicle speed exceeds a target vehicle speed.