JPS62231827A - Constant speed travel control device for automobile - Google Patents

Abstract

PURPOSE:To secure the stability of constant speed travel control and a good fuel consumption performance by providing a means of increasing fuel quantity in a defined operating area and restricting fuel increasing control when the feedback control of throttle opening is carried out. CONSTITUTION:A controller 7 has a target air-fuel ratio operating means 30 for operating a target air-fuel ratio based on signals from a travel resistance estimating means 24 and a target driving force operating means 25, to carry out both air-fuel ratio control and constant speed travel control. When the constant speed travel control is carried out, a power enriching operation in the air-fuel ratio control is not carried out. Accordingly, in this constant speed travel control, throttle opening control can be carried out without being affected by power enrichment. Thereby, the constant speed travel control can be stabilized while improving fuel consumption.

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. JP-A-57-1
An example of such a constant speed traveling device is disclosed in Japanese Patent No. 91431, and the disclosed constant speed traveling device includes means for setting a target vehicle speed, means for storing the set target vehicle speed, The vehicle is equipped with means for performing constant speed driving control based on the size of the vehicle speed deviation between the stored target vehicle speed and the actual vehicle speed, that is, the actual vehicle speed, and the constant speed driving setting operation is performed. After that, if the vehicle accelerates or decelerates before reaching the target vehicle speed, the target vehicle speed is reset to the vehicle speed when the acceleration or deceleration becomes zero, so that the actual vehicle speed is This prevents hunting when the vehicle speed converges to the target speed.

Furthermore, it has been known to control the air-fuel ratio to near the stoichiometric air-fuel ratio in a predetermined operating range for the purpose of improving fuel efficiency. In such engines, when the engine load increases beyond a predetermined value, so-called power enrichment is performed to increase the amount of fuel and enrich the mixture to prevent the engine from running out of power. .

(Problem to be Solved) However, in a vehicle equipped with both a constant speed traveling device and an air-fuel ratio control device as disclosed in the above-mentioned Japanese Patent Application Laid-open No. 57-191431, constant speed traveling control is not possible. Even if the engine load exceeds the specified value,
Fuel increase correction will be performed by air-fuel ratio control. However, constant-speed driving control attempts to maintain a constant speed by controlling the throttle opening in steady-state operating conditions where no significant increase in output occurs. Increasing the amount of fuel, i.e., performing power enrichment, increases the stability of the constant-speed driving control that controls the throttle opening, since the output change due to the increase in fuel overlaps with the output change due to the throttle opening control. Not only does this impair performance, but it is also disadvantageous in terms of fuel efficiency.

(Means for Solving the Problems) The present invention was constructed in view of the above circumstances, and provides stable constant speed driving control in a vehicle equipped with both a constant speed driving control device and an air-fuel ratio control device. It is an object of the present invention to provide a constant speed cruise control device that can perform the following operations and has good fuel efficiency.

The constant speed cruise control device of the present invention includes: a throttle valve installed in an intake passage, an actuator for adjusting the opening degree of the throttle valve, a fuel supply means for supplying fuel to the engine, and detecting the actual vehicle speed of the vehicle. a vehicle speed detection means for detecting a vehicle speed; 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 between the actual vehicle speed and the target vehicle speed; Throttle opening control amount calculating means for calculating the opening control amount of the valve, and actuating the actuator based on the output signal from the throttle opening control amount calculating means, and adjusting the throttle opening so that the actual vehicle speed becomes the target vehicle speed. and a fuel increase means for increasing the amount of fuel in a predetermined operating range, and is configured such that when the feedback control is performed, the fuel increase control is not performed by the fuel increase means. It is characterized by

In the engine according to the present invention, in a steady operating state where no significant change in output occurs, the actual vehicle speed is configured to converge to the target vehicle speed based on the size of the vehicle speed deviation between the target vehicle speed set by the driver and the actual vehicle speed. Constant-speed running control that controls the throttle opening and air-fuel ratio control that controls the fuel supply amount so that the air-fuel ratio converges to the target air-fuel ratio are performed.

When this constant speed running control is performed, the power enrich operation in the air-fuel ratio control is not performed.

According to a preferred embodiment of the constant speed running control of the present invention, first, the vehicle speed deviation between the actual vehicle speed and the target vehicle speed is determined, and then this deviation and the running condition of the vehicle, that is, the gradient of the road surface, road surface resistance, etc. The driving force required to reach the target vehicle speed is calculated. The opening control amount 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.

In this case, the constant speed cruise control device of the present invention is equipped with a map of the driving force required to converge to the target vehicle speed according to the target vehicle speed and the size of the vehicle speed deviation, and based on this map, the basic necessary The driving force value can be obtained.

The throttle opening control amount is determined based on the R-like target driving force obtained by correcting the driving force value obtained from the map in consideration of the driving condition.

(Effects of the Invention) According to the present invention, power enrichment is not performed when constant speed driving control is performed in an engine that performs both air-fuel ratio control and constant speed driving control. . Therefore, in the constant speed running control according to the present invention, throttle opening control can be performed without being affected by power enrichment in air-fuel ratio control. As a result, constant speed traveling control can be stabilized. Further, by limiting power enrichment as described above, it is possible to improve fuel efficiency.

(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. In order to adjust the opening degree of this throttle valve, a 0.7) l actuator is provided. The vehicle 1 of this example is
A controller 7 preferably including a microcomputer is provided, 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 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 vehicle speed sensor 10, and a signal representing the vehicle speed from the vehicle speed sensor 10 is also input manually 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. Man-powered.

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. A signal from the final throttle opening calculation means 27 is provided 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 6. ing.

The controller 7 also includes a running resistance predicting means 24 and a target air-fuel ratio calculating means 30 that calculates a target air-fuel ratio based on signals from the target driving force calculating means 25. Under the control of the fuel injection correcting means 31, the fuel injection correcting means 31 outputs a command signal to the fuel injection means 32 so as to prohibit power enrichment.

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 amount (THASC) required for the constant speed cruise control.

And 1. Compare the basic throttle opening (T)IOBJB) with the throttle opening for constant speed cruise control (TIIASC), and if the throttle opening (THASC) is large, change the throttle opening (T)IAsc) to the target throttle. If the basic throttle opening (THOBJB) is large, set the basic throttle opening (THOBJB) to the target throttle opening (THOBJ) and perform throttle control. conduct.

Next, to explain constant speed running control, in FIG. constant-speed running control is performed when the switch is on and the deceleration switch 12 or the acceleration switch 11 is not being operated.

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.

Further, when the acceleration switch 11 is operated, the controller 7 sets the target vehicle speed (V・5OBJ) every time the acceleration switch 11 is operated.
is increased by a constant value, and when the deceleration switch 12 is operated, it is decreased by a constant value every time the deceleration switch 12 is operated. 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). Deviation from target vehicle speed (VSOBJ) (0[
EFVS) is calculated.

When the vehicle speed deviation (DEFVS) exceeds a predetermined value (in this example, 15+n/h), the constant speed driving control is stopped and the constant speed driving control throttle 7) opening amount (T
HASC), target vehicle speed (VSOBJ), and integral element parameter (wKINT) are initialized.

If the vehicle speed deviation (DEFVS) 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 obtained by multiplying the vehicle speed deviation (DEFVS) by predetermined proportional data (DP). Next, set the target vehicle speed (V
When the actual vehicle speed (SOBJ) is greater than the actual vehicle speed (VSR), the 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), the target driving force is (TROBJ), then the proportional element (
The current target driving force (TROBJ) is calculated by decreasing P).
> Correct.

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, when the target vehicle speed (VSOBJ) is greater than the actual vehicle speed (VSR), the integral element parameter (WKINT) is set to the integral element (1
) and the actual vehicle speed (VSR) becomes the target vehicle speed (VSOBJ).
If it is larger than the integral element parameter (WKINT
), the current target driving force (TROBJ) is corrected by subtracting the integral element (1).

Next, since the power transmission efficiency changes depending on the oil temperature for the automatic transmission, the controller 7 calculates 0 as a correction coefficient that increases the target driving force (TROBJ) as the oil temperature becomes lower. 0 is the target driving force (TRO
BJ) to correct this.

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 (TPOBJ) is further corrected to calculate the final target driving force (Tll[18J).

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 calculates the throttle opening amount for constant speed driving control (THASC) based on the final target driving force (TRDBJ), actual vehicle speed (VSR), and optimum gear position (GPR) obtained in the above procedure. do. In this case, the controller 7 is equipped with a map for each gear stage that shows the relationship between the final target driving force (TROBJ), the actual vehicle speed (VSR), and the throttle opening amount for constant speed driving control (THASC). Using the map, the constant speed cruise control throttle opening amount (TIIASC) at the relevant gear stage is determined.

Throttle opening amount (T) IAs for constant speed driving control calculated by the constant speed driving control subroutine of FIGS. 3 and 4
c) is the target throttle opening (THOBJ) if the main routine shown in Figure 2 is satisfied and the predetermined conditions are satisfied.
The throttle opening control means, that is, the throttle actuator 6, controls the throttle opening so that the throttle opening converges to the constant speed cruise control throttle opening amount (THASC) by executing the interrupt routine shown in FIG. It will be done.

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, this vehicle speed pulse period (VST) is averaged to obtain the actual vehicle speed (t/SR).
Calculate.

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 (THE) for the past T seconds. Next, the above average vehicle speed (VSE
) and the average throttle opening (T), the average driving force (TRACE) during that period and the running resistance (RROAD) with no gradient are determined.

Next, the controller 7 calculates the average driving force (TRA("ε)
and the running resistance (, RROAD), and set 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 (ACCε) is determined.

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

FIG. 7 shows a subroutine for calculating the predicted vehicle resistance (RLOAD), target vehicle speed (VSOBJ), and stored vehicle speed (!, +RVS).

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 converted 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 controller 7 determines the maximum driving force (TRMAX) at each gear position from a map showing the relationship between the actual vehicle speed (VSR) and the maximum driving force (TRMAX) that can be exerted at each gear position (GPR). If the maximum driving force (TRMAX) of the gear position is smaller than the target driving force (TROBJ), it is impossible to maintain the gear position and secure the required driving force.
A command signal is sent to the shift control means of the transmission 3, that is, the shift actuator 9, 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.

FIG. 9 shows a flowchart of the air-fuel ratio control subroutine. In this routine, the controller 7 uses a map to determine the target air-fuel ratio based on the values of the target driving force (TROBJ) and the actual vehicle speed (VSR). Find (AFOBJ).

Then, based on the value of this target air-fuel ratio (AFσBJ), it is determined whether the current operating state satisfies the power enrichment conditions. In this case, the controller 7 determines that the power enrichment condition is satisfied if the target air-fuel ratio (AFOBJ) is smaller than a predetermined value. but,
In the control of this example, power enrichment is not performed when constant speed driving control is performed, so a power enrichment prohibition signal is sent to the fuel injection means. As described above, in the constant speed running control of this example, the adverse effects of the air-fuel ratio control are eliminated as much as possible, and therefore the control can be stabilized. In this case, power enrichment is controlled to be limited during constant speed driving control, resulting in improved fuel efficiency. Note that in driving conditions where a significant change in output occurs, such as during acceleration, which essentially requires an increase in the amount of fuel, constant speed driving control is not performed, so air-fuel ratio control is not affected.

In the above-mentioned embodiment, when performing shift control, the maximum driving force of the relevant gear stage is compared with the target driving force, but it is also possible to perform shift control using other means. .

For example, FIG. 11 shows a flowchart of a speed change control subroutine when performing speed change control between third speed and fourth speed with focus on throttle opening. In FIG. 11, when performing speed change control, the controller 7
determines the gear position, and if the current gear position is 3rd speed, determines whether the throttle opening is smaller than a predetermined value e2, and if it is smaller than the predetermined value e2, causes the shift control means to shift up. Send a signal. Also, the predetermined value e2
If it is not smaller than that, it is assumed that there is insufficient margin for running in third gear, and the vehicle maintains third gear. When the current gear position is the 4th gear, the throttle opening is set to a predetermined value e1.
If it is larger than the predetermined value e1, it is determined that the driving force is insufficient and a shift down signal is output to the speed change control means.

[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 4, 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 an air-fuel ratio control subroutine for prohibiting power enrichment, FIG. 10 is a flowchart of a throttle opening control execution routine, and FIG. 2 is a flowchart of a speed change control subroutine. 1...Vehicle, 2...Engine, 3...
... Automatic transmission 5 ... Drive shaft, 6 ...
・・Throttle actuator 7・・・Controller, ・・・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, I6... Transmission switch, 19...
...accelerator pedal, 32...fuel injection means. Figure 2 Main routine Figure 4 Subroutine Figure 6 Subroutine Figure 7 Subroutine Figure 9 Subroutine Subroutine diagram Figure 11

Claims (1)

[Claims] A throttle valve provided in an intake passage, an actuator for adjusting the opening degree of the throttle valve, a fuel supply means for supplying fuel to the engine, a vehicle speed detection means for detecting the actual vehicle speed, and a target vehicle speed setting for the vehicle. a target vehicle speed setting means for detecting a vehicle speed, a deviation detecting means for detecting a vehicle speed deviation between the actual vehicle speed and the target vehicle speed, and a throttle opening for calculating an opening control amount of a throttle valve according to an output signal from the deviation detecting means stage. a control amount calculation means; a feedback control means for controlling the throttle opening so that the actual vehicle speed becomes the target vehicle speed by operating the actuator based on the output signal from the throttle opening control amount calculation means; and a predetermined driving range. a constant speed driving control device for a motor vehicle, comprising: a fuel increase means for increasing the amount of fuel; the device is configured such that when the feedback control is performed, the fuel increase control is not performed by the fuel increase means; .