JPH0712803B2 - 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 this case, if the target vehicle speed is set too low, the engine speed will decrease and the operating state will become unstable. Also, it will be difficult to precisely control the intake air by the throttle opening, so stable constant speed running control will be possible. There is a problem that you can not do it. For this reason, in an engine equipped with a conventional constant speed traveling control device, a lower limit value that can be set as a target vehicle speed is provided, and if the target vehicle speed is smaller than this lower limit value, constant speed traveling control is not performed. ing. For example, "Cosmo, published in September 1981
The Luce maintenance manual states that the range that can be set as the target vehicle speed is 40 to 100 km / h.

(Problems to be Solved) As described above, in the conventional constant speed traveling control device, the constant speed traveling is uniformly prohibited below the set lower limit value of the target vehicle speed. However, when the engine temperature is low, the vaporization and atomization of the air-fuel mixture are bad even if the target vehicle speed is set to be equal to or higher than the set lower limit value, so that stable constant speed traveling control may not be possible. In addition, if the lower limit of the target vehicle speed that can be set is increased in order to perform stable constant-speed running control without being affected by the engine temperature, the range in which constant-speed running control can be performed will be reduced, resulting in constant-speed running. This will reduce the usefulness of the control.

(Means for Solving the Problem) The present invention is configured in view of the above circumstances, and it is possible to secure as wide a range as possible to perform constant speed traveling control, and further, to a set target vehicle speed. On the other hand, it is an object of the present invention to provide a constant-speed traveling device for an automobile, which can stably converge.

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,
The throttle opening calculation means for calculating the opening of the throttle valve according to the output signal from the deviation detection means, and the actual vehicle speed converges to the target vehicle speed based on the output signal from the throttle opening calculation means. A feedback control means for operating an actuator to control the throttle opening, and a means for changing a lower limit value of a target vehicle speed that can be set as an object of the feedback control according to an engine temperature are provided.

According to the present invention, when the feedback control of the throttle opening is being performed, that is, the target vehicle speed setting range in which the constant speed traveling control can be performed is changed according to the engine temperature. When the constant speed traveling control is performed in the operating state where the temperature is low, the lower limit setting value of the target vehicle speed is set relatively high and set lower as the engine temperature rises.

Further, in a preferred aspect of the present invention, first, a vehicle speed deviation between the actual vehicle speed and the target vehicle speed is obtained, and then the vehicle speed is set to the target vehicle speed in consideration of the deviation and the running state of the vehicle, that is, the road gradient, road surface resistance, and the like. The driving force required to reach Then, the opening of the throttle valve is determined according to the magnitude of the driving force, and the opening of the throttle valve is controlled via the actuator.

In this case, 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 required drive The value of 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.

(Effects of the Invention) As described above, in the constant speed traveling control device of the present invention, the vehicle speed range that the driver can set as the target vehicle speed is changed by the engine temperature. Therefore, the driver can select the target vehicle speed in a wide range when the engine temperature is relatively high. Further, in a state where the engine temperature is low such that the constant speed traveling control becomes unstable, the lower limit value of the target vehicle speed is automatically set to a large value. Travel 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 control 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 vehicle resistance based on signals from the target vehicle speed setting circuit 23 and the vehicle speed detection means 18 for predicting the traveling resistance of the vehicle based on signals from the gradient detection means 22 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 traveling resistance prediction means 24 and the target driving force calculation means 25, and the signal from the target air-fuel ratio calculation means 30 is a fuel. The fuel injection correction means 31 is input to the injection correction means 31 and 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, etc. are read and these signals are A / D converted. Next, the controller 7 causes the basic throttle opening calculation means 21 to calculate the basic throttle opening (THOBJB) from the accelerator position signal A / D converted by the accelerator position detection means 20.

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

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

Next, the constant-speed running control will be described. In FIG. 3, the controller 7 includes a main switch 14, a brake switch 15 (ON when the brake is not operated), and a transmission switch 16 (not in neutral but in any shift stage). The target vehicle speed setting is performed when (ON when the vehicle is on) is on and the operation of the deceleration switch 12 or the acceleration switch 11 is completed. At this time, it is determined whether or not the target vehicle speed set by the driver is within the allowable range of the constant speed traveling control device of this example.

In this case, in this case, the range in which the driver can set the target vehicle speed is changed according to the engine temperature. The controller 7 has a map of the engine cooling water temperature and the target vehicle speed setting lower limit value as shown in FIG. 11, and the target vehicle speed lower limit value increases as the engine temperature decreases. In addition, the target vehicle speed setting upper limit value in this example is set to 105 km / h.

When the target vehicle speed set by the driver is within the above-mentioned allowable range, the controller 7 performs constant speed traveling control in the procedure described below. If the set target vehicle speed is smaller than the lower limit value, the controller 7 sets the target vehicle speed (VSOBJ) to zero. Therefore, in this case, the constant speed traveling control is not performed unless the target vehicle speed is subsequently changed to fall within the allowable range.

On the other hand, when the target vehicle speed (VSOBJ) is higher than the upper limit value, the target vehicle speed (VSOBJ) is set to the upper limit value, that is, 105 Km / h.

After that, the controller 7 executes the subroutine shown in FIG. 7 and adopts the final target vehicle speed (VSOBJ) as the final target vehicle speed (VSOBJ) unless the target vehicle speed (VSOBJ) set above is changed by the memory vehicle speed (MRVS). Speed control is performed.

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

Then, the vehicle speed deviation (DEFVS) is a predetermined value, 15K in this example.
When it exceeds m / h, the constant speed running control is stopped and the throttle opening amount for constant speed running control (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)
To calculate. In this case, the proportional element (P) is the vehicle speed deviation (DEFV
It is obtained by multiplying S) by a predetermined proportional data (DP). Next, the target vehicle speed (VSOBJ) is the actual vehicle speed (VSR)
If it is larger, the proportional element (P) is added to the target driving force (TROBJ). If the actual vehicle speed (VSR) is larger than the target vehicle speed (VSOBJ), the proportional element (P is calculated from the target driving force (TROBJ). P) to reduce the current target driving force (TROB
Correct J).

Next, the controller 7 calculates the integral element (I) from the integral data (DI) in order to calculate the final target driving force (TROBJ). Then, the target vehicle speed (VS
If OBJ) is greater than the actual vehicle speed (VSR), the integral element (I) is added to the integral element parameter (WKINT) 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 integral element (I) from the integral element parameter (WKINT).

Next, since the power transmission efficiency changes depending on the oil temperature for the automatic transmission, the controller 7 calculates a correction coefficient Ko that increases the target driving force (TROBJ) as the oil temperature is lower, and calculates this correction coefficient Ko. This is corrected by multiplying the 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 obtain the predicted vehicle resistance obtained from the interruption subroutine shown in FIG. The target driving force (TROBJ) is further corrected by (RLOAD) to calculate the final target driving force (TROBJ).

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

Next, the controller 7 determines the throttle opening amount (T) for constant speed traveling control based on the final target driving force (TROBJ), the actual vehicle speed (VSR) and the optimum shift speed (6PR) obtained by the above procedure.
HASC) is calculated. 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. Using the map, the throttle opening amount for constant speed running control (THAS
Determine C).

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. (THOBJ), and the throttle opening is controlled by the execution of the interrupt routine shown in Fig. 10 (THASC)
Throttle control is performed via the throttle opening control means, that is, the throttle actuator 6 so as to converge to.

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. In calculating the actual vehicle speed (VSR), the controller 7 reads the pulse signal from the vehicle speed sensor 10 and measures the vehicle speed pulse period (VST). Next, this vehicle speed pulse period (VS
T) 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 that the average vehicle speed (VSE) for the past T seconds and the average throttle opening (T
HE) is calculated. Next, based on the above-mentioned average vehicle speed (VSE) and average throttle opening (THE), the average driving force (TRACE) and running resistance without a gradient (RROAD)
Ask for.

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

Further, the controller 7 changes the vehicle speed in the past T seconds (VS
D) is calculated, and the speed change per unit time, that is, the average acceleration (ACCE) is calculated.

Then, the difference between the virtual acceleration (ACCV) and the average acceleration (ACCE) is divided by the gravitational acceleration to obtain the road surface gradient (RAMP).

Figure 7 shows the predicted resistance of the vehicle (RLOAD), the target vehicle speed (VSO
BJ), 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, while setting the initial value of the integral element parameter (WKINT), the actual vehicle speed (VSR) is stored in the vehicle speed (MRVS).
Is stored in a predetermined storage location. 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 detects the current gear stage (GPR) from the signal from the gear position sensor 8. Next, the controller 7 obtains the maximum driving force (TRMAX) at the gear position from the map showing the relationship between the actual vehicle speed (VSR) and the maximum driving force (TRMAX) that can be exhibited at each gear position (GPR). If the maximum driving force (TRMAX) of the gear is smaller than the target driving force (TROBJ), it is impossible to maintain the gear and maintain a predetermined driving force. A command signal is sent to the shift control means, that is, the shift actuator 9 so as to shift down.

When the maximum driving force (TRMAX) of the gear is larger than the target driving force (TROBJ), the controller 7 determines the margin driving force (STR) in the gear, that is, the maximum driving force (TRMAX) and the target driving force (TRMAX). When the difference from the driving force (TROBJ) is calculated and 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 uses the map based on the values of the target driving force (TROBJ) and the actual vehicle speed (VSR). Ask for (AFOBJ).

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. In this case, the controller 7 determines that the target air-fuel ratio (AFOBJ) is in the power enrichment range when the target air-fuel ratio (AFOBJ) is equal to or greater than a predetermined value. 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 the present example, the target vehicle speed setting lower limit value is changed according to the engine cooling water temperature, so that the range in which the constant speed traveling control is possible can be effectively increased. At the same time, it is possible to always achieve stable constant speed traveling control.

[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, FIG. 10 is a flowchart of a throttle opening control execution routine, and FIG. 11 shows a relationship between engine cooling water temperature and a target vehicle speed setting lower limit value. It is a graph. 1 ... Vehicle, 2 ... Engine, 3 ... Automatic transmission, 5 ...
… Drive axis, 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; a throttle opening calculating means for calculating an opening of a throttle valve in accordance with an output signal from the deviation detecting 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 output signal from the means, and a target that can be set as an object of the feedback control according to the engine temperature. A constant speed running control device for an automobile, comprising: a means for changing a lower limit value of the vehicle speed.