JPS62231828A - Constant speed travel control device for automobile - Google Patents

Abstract

PURPOSE:To release a torque shock at the time of returning to a constant speed travel by providing a returned throttle opening restricting means for restricting the controlled variable of a throttle opening when returning from a condition that the feedback control of the throttle opening is removed. CONSTITUTION:A controller 7 has a throttle opening operating means 27 for operating the controlled variable of a throttle opening based on signals from a vehicle speed detecting means 18, a travel resistance estimating means 24, a target driving force operating means 25, and a speed change judging means 26, to carry out the feedback control of a throttle opening with respect to a target vehicle speed. When returning from a condition that the feedback control is removed, the controlled variable of the throttle opening is restricted. Accordingly, since there is no sudden change in throttle opening immediately after returning, the generation of a torque shock at the time of returning can be effectively prevented.

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
91431 discloses an example of such a constant speed traveling device, and this disclosed constant speed traveling device includes means for setting a target vehicle speed, and means for storing the set target vehicle speed. , a means for performing constant speed driving control based on the magnitude of the vehicle speed deviation between the stored target vehicle speed and the actual vehicle speed. In other words, if the vehicle accelerates or decelerates before reaching the target vehicle speed after the constant speed driving setting operation is performed, the target vehicle speed is set to the vehicle speed when the acceleration or deceleration reaches zero. By resetting the vehicle speed, it is possible to prevent hunting when the actual vehicle speed converges to the target vehicle speed.

(Problem to be solved) By the way, constant speed cruise control is normally performed in a steady state of operation where no significant changes in output occur. If this occurs, it will be lifted. In this case, if the constant speed driving control is restarted by setting a new target vehicle speed every time the constant speed driving control is canceled, the operation becomes complicated and the burden on the driver increases.

In view of these circumstances, when the driver operates the accelerator or brake pedal while driving at a constant speed, the constant speed driving control is automatically canceled and when the vehicle returns to steady driving state. 2. Description of the Related Art A constant speed cruise control device including a return switch for automatically returning to constant speed cruise control is conventionally known. However, when returning to constant speed driving from an unsteady driving state, if the deviation between the actual vehicle speed and the target vehicle speed is large, the throttle opening control amount will increase at the time of return, resulting in torque shock. However, a problem arises in that the passenger feels uncomfortable.

(Means for Solving the Problem) The present invention was constructed in view of the above circumstances, and is capable of alleviating as much as possible the torque shock when returning to constant speed running, thus reducing the discomfort caused to the occupants. The purpose of the present invention is to provide a constant-speed traveling device for automobiles that can achieve this.

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;
throttle opening calculation means for calculating the opening of the throttle valve according to the output signal from the deviation detection means; and feedback control means for controlling the throttle opening degree by operating the actuator. Furthermore, the constant speed cruise control device of the present invention includes:
The present invention includes a return throttle opening degree limiting means for limiting the throttle opening degree control amount when returning the feedback control from the state where the feedback control is canceled, that is, when returning to the constant speed running control.

In a preferred embodiment of the present invention, the driver may press the accelerator pedal;
Alternatively, when constant speed driving control is canceled by operating a brake pedal or the like, the actual vehicle speed at the time of cancellation is stored. Then, when constant speed driving control is resumed next time, this stored actual vehicle speed is set as the target vehicle speed, and feedback control of the throttle opening degree is performed with respect to this target vehicle speed. In this case, in the present invention, if the deviation between the target vehicle speed and the actual vehicle speed at the time of return is large, and therefore the throttle opening control amount becomes large, the throttle opening control amount is limited.

In such a case, even after the constant speed cruise control is restored, control is preferably performed such that the actual vehicle speed converges to the target vehicle speed while maintaining the throttle opening control amount at the time of restoration.

(Effects of the Invention) According to the control of the present invention, the conditions for returning the constant speed driving control are set so that the throttle opening control amount does not become unreasonably large, and the sudden change in the throttle opening is prevented immediately after the return. Since the torque shock is controlled so as not to occur, it is possible to effectively prevent the occurrence of torque shock at the time of return.

(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 the intake passage of the 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 microcomputer, 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.

Furthermore, 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. Man-powered.

The control, -rough, includes a switch input circuit 17 that receives signals from the various switches mentioned 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. accelerator position detection means 20 for detecting the degree position, basic throttle opening calculation means 21 for calculating the basic throttle opening based on the signal from the accelerator position detection means, slope detection means 22 for detecting the slope of the road surface, and the above-mentioned switch. a target vehicle speed setting circuit 23 that sets a target vehicle speed based on signals from the input circuit 17 and the vehicle speed detection means 18;
and a running resistance prediction means 24 that predicts the running resistance of the vehicle based on the signal from the slope detection means 22, a target drive that calculates the target driving force of the vehicle based on the signals from the target vehicle speed setting circuit 23, and the vehicle speed detection means 18. Each vehicle includes a force calculation means 25, a vehicle speed detection means 18, a running resistance prediction means 24, and a shift determination means 26 for determining an appropriate gear position of the automatic transmission based on signals from the target vehicle driving force calculation means 25. ing.

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 inputted to the shift actuator 6. 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. The amount of fuel to be injected is manually corrected by the injection correction means 31, and the fuel injection correction means 31 outputs a command signal to the fuel injection means 32 to inject a predetermined amount of fuel. There is.

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.

First, the controller 7 initializes the system and controls 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. It reads signals from and A/D converts these signals. Next, the controller 7 uses the accelerator position detecting means 20 to
/D converted accelerator position signal is calculated by basic throttle opening calculation means 21 to calculate basic throttle opening (TI(OB)
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.

Then, compare the basic throttle opening (THOBJB) and the throttle opening amount for constant speed driving control (THASC), and if the throttle opening amount (THASC) is large,
Throttle control is performed by setting the throttle opening amount (THASC) to the target throttle opening (THOBJ), and when the basic throttle opening (TIIOBJB) is large, the basic throttle opening (T) IOBJB) is set to the target throttle opening. (THOBJ) and perform throttle control.

Next, to explain constant speed driving control, in FIG. It is defined as control that includes functions, that is, constant speed running, acceleration, deceleration, and return.

When the conditions for starting constant speed driving control are met, the controller 7
determines whether the target vehicle speed setting condition is met.

This criterion is based on the acceleration switch 11 or 1. This refers to the time when the deceleration switch 12 is returned after being pressed. Therefore, it is the last operation of the acceleration switch 11 and deceleration switch 12 that satisfies the target vehicle speed setting condition. If the target vehicle speed setting conditions are satisfied, the controller 7
The subroutine shown in FIG. 7 is executed, and the target vehicle speed (V
SOBJ) to perform constant speed driving 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, in the constant speed cruise control device of this example, under some conditions (
For example, when the main switch 14, brake switch 15, or transmission switch 16 is turned off, the actual vehicle speed (VSR) is lower than the target vehicle speed by a certain value (15
There are cases where the deviation is more than Km/h. ) It is possible to return the constant speed running control from the stopped state to the original state.

Next, the controller 7 executes the return subroutine shown in FIG. First, it is determined whether the return switch 13 is pressed, and if it is pressed, the FRIESUME is set to 1.
Set it to start recovery.

(If the return switch 13 is not pressed, it will not return.) When returning to constant speed running control, control is performed to suppress the occurrence of torque shock as much as possible.

In FIG. 11, the controller 7 stores the actual vehicle speed at the time of canceling the constant speed driving control, and when returning to the constant speed driving control, uses this stored vehicle speed (MRVS) and the actual vehicle speed at the time of restoration (V
SR) is added to the actual vehicle speed (VSR), this is set as the initial value of the target vehicle speed (VSOBJ) at the time of recovery, and constant speed driving control is restarted.

Once the constant speed driving control is restarted, the target vehicle speed is increased by a constant value (ORBS), and when the initial target vehicle speed set by the driver is reached, the control by this return subroutine is started. finish.

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). Calculate the deviation (DEFVS) from the target vehicle speed (VSOBJ).

Then, when the vehicle speed deviation (DEFVS) exceeds a predetermined value, in this example, 15 km/h, and the return state flag (
If FRESUME) is not 1 or 2, it is detected whether the return operation is in progress, and if the return operation is not in progress, the constant speed cruise control is stopped and the constant speed cruise control throttle opening amount ( TIIASC), target vehicle speed (
VSOBJ) and integral element parameters (WKINT) are initialized.

If the vehicle speed deviation (DεFVS) is within 15 Km/h, a proportional element (P) for calculating the final target driving force (TRDBJ) is calculated. In this case, the proportional element (P) is obtained by multiplying the vehicle speed deviation (DεFVS) by predetermined proportional data (OP). 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 ff5OBJ), the target driving force ( TROBJ) from the proportional element (P
) to calculate the current target driving force (TROBJ).
Correct.

Next, the controller 7 outputs the final target driving force (TROBJ
) from the integral data (DI) to calculate the integral element (
+) is calculated. Similarly to the above proportional control, when the target vehicle speed (VS[18J) is larger than the actual vehicle speed (VSR), the integral element (1) is added to the integral element parameter (tvKINT), and the actual vehicle speed (VSR) becomes the target vehicle speed. (VS
OBJ) If the twist is also large, the integral element parameter (
The current target driving force (TROBJ) is corrected by subtracting the integral element (1) from the current target driving force (TROBJ).

Next, since the power transmission efficiency changes depending on the oil temperature for the automatic transmission, the controller 7 calculates a correction coefficient of 0 according to the oil temperature, and sets the correction coefficient to 0 as the target driving force (TROBJ). Correct this by multiplying by

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 (GP!?) of the automatic transmission according to the current driving state of the vehicle.

Furthermore, the controller 7 executes the air-fuel ratio control subroutine shown in FIG.
) and the stoichiometric air-fuel ratio, that is, the air-fuel ratio correction ff
1cA, and calculate this air-fuel ratio correction amount CAF.
The air-fuel ratio correction coefficient KAF is calculated based on.

Next, the controller 7 calculates the throttle opening amount for constant speed driving control (THASC) based on the final target driving force (TROBJ), 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 (T). , Using this map, determine the throttle opening amount (T)IAsc) for constant speed driving control at the relevant gear position.
Determine.

In this example, when constant speed driving control is performed, fuel increase based on air-fuel ratio control, that is, power enrichment is not performed. The system uses throttle opening control to compensate for the decreasing tendency of output that occurs because power enrichment is not performed. That is, the controller 7 corrects the throttle opening amount for constant speed cruise control (THASC) using the air-fuel ratio correction coefficient KAF, and finally adjusts the throttle opening amount for constant speed cruise control (THASC) by using the air-fuel ratio correction coefficient KAF.
C) is determined.

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 (TIIOBJ) if the predetermined conditions are satisfied in the main routine of Fig. 2.
The throttle opening control means, that is, the throttle actiniator 6, controls the throttle opening so that the throttle opening converges to the throttle opening amount 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 (V
Based on the SE) and the average throttle opening (TI(AR)), the average driving force (TRACE) between them and the running resistance (RROAD) in a state where there is no gradient are determined.

Next, the controller 7 calculates the average driving force (TRACIE)
The difference between the running resistance (RROAD) and the above running resistance (RROAD) is determined, and this value is set 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
Divide the difference between E) by the gravitational acceleration to calculate the road surface slope (RAM
Find P ).

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 controls the actual vehicle speed (VSR) obtained in FIG. 5 and the road surface slope (RAi) obtained in FIG.
, IP), the predicted running resistance (RL
OAD). Next, the integral element parameter (WK
In addition to setting the initial value of INT), the actual vehicle speed (VSR
) is stored in a predetermined storage location as a memorized vehicle speed (MRVS). Further, the vehicle speed value set by the driver is stored as a 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 the speed change control subroutine 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 that gear position and secure the required driving force. A command signal is sent to the speed change control means, that is, the speed change 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 controls the target driving force (TROBJ) and the actual vehicle speed (VSR).
Based on the value of , the target air-fuel ratio (AFOBJ
).

Then, based on the value of this target air-fuel ratio (AFOBJ), it is determined whether the current operating state satisfies the power enrichment conditions. In this case, the controller 7 determines that the vehicle is in the power enriched region when the target air-fuel ratio (AFOBJ) is equal to or higher than a predetermined value.

When the power enrichment conditions are satisfied, the deviation between the stoichiometric air-fuel ratio and the target vehicle air-fuel ratio, that is, the air-fuel ratio correction amount C
AP is calculated, and an air-fuel ratio correction coefficient KAP for correcting the target air-fuel ratio (AFOBJ) is determined according to the value of the air-fuel ratio correction I CA F using a map. However, in the control of this example, when performing constant speed running control, power enrichment is not performed, so a power enrichment prohibition signal is sent to the fuel injection means. Therefore, in the control of this example, even if the engine is in an enriched region where an output shortage occurs, fuel increase control is not performed on the fuel injection means, and the insufficient output is compensated for by throttle opening control.

Note that if the value of the target air-fuel ratio (AFOBJ) does not satisfy the power enrichment conditions, the controller 7
Set the air-fuel ratio correction coefficient KAF to 1.0.

As described above, in the constant speed driving control of this example, control is performed so that a sudden change in the target vehicle speed does not occur when the constant speed driving control returns, so sudden changes in the throttle opening degree are suppressed. Therefore, the occurrence of torque shock at the time of return can be effectively suppressed. Also,
In this example, instead of simply controlling the throttle opening according to the vehicle speed deviation as in the past, the target driving force is determined according to the driving condition and the throttle opening is controlled according to the magnitude of the target driving force. Therefore, constant speed driving control with good convergence can be performed.

[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. Figure 10 is a flowchart of the air-fuel ratio control subroutine for determining the air-fuel ratio correction coefficient, Figure 10 is a flowchart of the throttle opening control execution routine, and Figure 11 is the return control that performs control when returning to constant speed driving control. It is a flowchart of a subroutine. 1...Vehicle, 2...Engine, 3...
... Automatic transmission 5 ... Drive shaft, 6 ...
・・Throttle actuator 7・・・Controller, 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. Figure 2 Main Routine Figure 4 Figure 5 Figure 6 Subroutine Figure 7 Subroutine Subroutine Figure 9 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 a throttle valve according to 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; and a throttle opening control amount for returning the feedback control from the state where the feedback control has been canceled. A constant speed running control device for a motor vehicle, comprising: return throttle opening limit means for limiting return throttle opening.