JPH08113056A - Constant speed travel device for automobile - Google Patents

Abstract

PURPOSE: To improve the converging accuracy on an objective vehicle speed, by controlling an actuator for opening/closing a throttle valve so that an actual vehicle speed can be kept the objective vehicle speed and also by changing an actuator control period in accordance with travel resistance. CONSTITUTION: In a device equipped with a vehicle speed sensor 1, various input switches 2 for setting the objective vehicle speed for constant-speed traveling or issuing an order to change the object, an operation quantity detecting means 3 of an accelerator pedal, and an opening detecting means 6 of a throttle valve, etc., based on output signals of these, an actuator 4 for controlling a throttle valve 5 is controlled by a control means 7. That is, the actuator 4 is controlled so that an actual vehicle speed may be kept a target vehicle speed during a constant speed traveling control. In this case, traveling resistance is computer using an output shaft torque and a vehicle speed, and a control period or the actuator 4 is changed in accordance with the travel resistance. A control quantity for the actuator 4 is also changed in accordance with a present opening of the throttle valve 5 or the travel resistance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a constant speed control device for an automobile for maintaining and controlling an actual vehicle speed at a predetermined target vehicle speed, and more particularly to a constant speed traveling device with improved accuracy of convergence to the target vehicle speed.

[0002]

2. Description of the Related Art A constant-speed running device for an automobile is a device for carrying out constant-speed running with a vehicle speed selected by a driver as a target vehicle speed, and is equipped with a main switch for operating the device. Further, there is a vehicle equipped with a speed increasing switch and a speed reducing switch for changing the target vehicle speed during traveling at a constant speed. If these switches are kept pressed, an acceleration or deceleration command is generated, the throttle valve opening degree and the like are controlled, and the vehicle speed is continuously increased or decelerated. When the pressing of the switch is stopped, the acceleration and deceleration commands disappear, and the vehicle speed at that time becomes the new target vehicle speed. Further, when the brakes are operated, the constant speed traveling is released to reduce the vehicle speed to the target vehicle speed or less. After that, if you want to return to the previous target vehicle speed,
Just operate the return switch. Further, when the accelerator pedal is depressed while traveling at a constant speed, it is possible to accelerate in conjunction with the accelerator pedal. Many proposals have been made for such a constant speed traveling device, and it is described in, for example, Japanese Utility Model Publication No. 50-43626.

[0003]

However, in the conventional constant-speed traveling device, a deviation between the target vehicle speed and the actual vehicle speed occurs due to traveling resistance to the vehicle during constant-speed traveling. The feeling of acceleration and deceleration depending on the acceleration / deceleration request by operating the speed increasing switch and the decelerating switch differs depending on the traveling situation. When the accelerator pedal is depressed to accelerate the vehicle, the accelerator pedal is released, and then the vehicle is returned to the constant speed running state, it takes time to converge to the target vehicle speed due to a response delay of the vehicle speed. The present invention has been made in view of the above problems, and an object thereof is to provide a constant-speed traveling device that can appropriately change a target vehicle speed and can obtain a feeling of acceleration and deceleration adapted to a driver's feeling. Especially.

[0004]

According to the present invention, the convergence time to the target vehicle speed is shortened by changing the control cycle of the actuator for converging the actual vehicle speed to the target vehicle speed according to the running resistance. Further, by changing the control amount of the actuator according to the current traveling state in response to the acceleration and deceleration requests during constant speed traveling, it is possible to obtain the feeling of acceleration and deceleration as requested by the driver.

Further, the throttle valve opening according to the accelerator pedal operation amount and the throttle valve opening according to the target vehicle speed are compared to perform acceleration / deceleration request for interlocking with the accelerator pedal and switching between constant speed running control, and interlocking with the accelerator pedal. When returning from the control to the constant speed running control, the accelerator pedal interlocks the vehicle until it reaches an opening that is smaller than the throttle valve opening for running at the target vehicle speed. I will provide a. The determination of the idling state of the engine is made by using the operation amount of the accelerator pedal, and the determination of the idling state is invalid during the constant speed traveling control.

[0006]

When the running resistance is within a certain range, there are few factors that cause the deviation between the target vehicle speed and the actual vehicle speed. Therefore, the control cycle is lengthened and the control amount to the actuator is fixed to maintain the target vehicle speed. To do so. On the other hand, when the running resistance changes and its value becomes large or small (uphill road, etc.), a deviation easily occurs between the target vehicle speed and the actual vehicle speed. Therefore, shorten the control cycle to reach the target vehicle speed. Improve the convergence speed of. In addition, if the control amount to the actuator is uniquely set regardless of the traveling state in response to the acceleration or deceleration request during constant speed traveling control, the actual acceleration or deceleration state will differ from the driver's request. come. Therefore, by changing the control amount to the actuator according to the traveling state, it is possible to always provide the acceleration / deceleration feeling as requested by the driver.

The means for comparing the throttle valve opening based on the accelerator pedal operation amount and the throttle valve opening for achieving the target vehicle speed to determine the acceleration request linked with the accelerator pedal and the switching between the constant speed running control are accelerator pedals. When shifting from the linked running state to the constant speed running state, by running the accelerator pedal linked until the throttle valve opening for running at the previously set target vehicle speed becomes smaller than the throttle valve opening, It becomes possible to perform control that takes into account the actual vehicle speed response delay, and it is possible to provide the feeling of deceleration as requested by the driver. By invalidating the determination of the idling state of the engine during the constant speed running control, it is possible to prevent erroneous determination of the idling state when there is no accelerator pedal operation amount and the engine is not in the idling state. .

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of a constant speed traveling device according to the present invention. A vehicle speed sensor as a vehicle speed detecting means 1, various input switches as a means 2 for setting or changing a target vehicle speed for constant speed traveling, and a potentiometer and a throttle valve as an accelerator pedal operation amount detecting means 3. It is provided with a potentiometer as opening degree detection means 6, an actuator 4 for controlling the throttle valve 5, and a control means 7 for controlling the actuator 4 to maintain the vehicle speed at the target vehicle speed. The vehicle speed control means 7 includes a target vehicle speed change control unit, a control cycle change unit, an acceleration / deceleration control amount change unit, a running resistance estimation calculation unit, and the like. These are arithmetic units and are composed of, for example, an AD converter, a microprocessor, a memory, a DA converter, and the like.

The control means 7 outputs a control signal to the actuator 4 and controls the opening of the throttle valve 5 to control the engine output. The accelerator pedal potentiometer generates an analog signal corresponding to the accelerator pedal operation amount, and the control device 7 calculates a control signal of the throttle valve opening according to the signal or determines the idling state of the engine. The throttle valve potentiometer generates an analog signal corresponding to the throttle valve opening. During the constant speed traveling control, the control device 7 feeds back the signal to calculate the throttle valve opening that achieves the target vehicle speed, and outputs the control signal corresponding to the opening to the actuator. The actuator realizes constant speed traveling by controlling the throttle valve based on the control signal.

In a normal fuel control device, if the intake air amount, that is, the throttle valve opening changes, the fuel supply amount is calculated accordingly, and by controlling the throttle valve opening, The engine power can be controlled. The vehicle speed detecting means 1 detects the vehicle speed, for example, by detecting the rotation speed of the output shaft of the transmission with an electromagnetic pickup. The traveling resistance estimation unit estimates and calculates the traveling resistance F _R according to the following formula, for example, based on the output shaft torque T ₀ and the vehicle speed V.

F _R = F _r + F _A + F _θ = f (T ₀ , V, ΔV) where F _r is a rolling resistance of the vehicle and is a constant, and F _A is an air resistance which is proportional to the square of V. , The output torque T ₀ is
For example, it is a term calculated from engine speed, turbine speed, gear ratios, and torque converter characteristics. Further, Fθ is a gradient resistance, and when the output shaft torque is T ₀ , the flat running torque is T _RL , and the acceleration torque is T _a , (T ₀ −T
_This is a term proportional to _RL− T _a ). T _RL is (F _r + F _A )
And T _a is proportional to the acceleration, that is, the difference ΔV of the vehicle speed V, so that the running resistance F _R is eventually the output shaft torque T.
₀ , vehicle speed V, known function f (T ₀ , V, ΔV) of ΔV
Therefore, it can be calculated from the detected values of the output shaft torque and the vehicle speed.

Next, each processing in the control means 7 will be described. FIG. 2 is a flow chart showing an example of calculation in the control means 7. These calculations are repeatedly executed at a predetermined timing. First, the running resistance of the vehicle is calculated and estimated based on each detection information (P1). next,
The control cycle is set based on the estimation result in P1 (P
2). Subsequently, self-diagnosis of the constant speed traveling device and determination of the diagnosis result are performed (P3, P4). If there is no abnormality as a result of the diagnosis, it is judged whether or not there is a request to end constant speed running, a brake switch ON, a cancel request other than the constant speed running vehicle speed range (P5), and if there is a cancel request, the normal speed running is resumed. The process for returning to running (P6) and the flag "CRUISE" indicating the constant speed running state are cleared (P7), and the process ends. If an abnormality is found in the judgment of the diagnosis result in P4, P
The process of P6 and P7 is performed and the process ends.

If there is no cancel request at P5, the input of the constant speed traveling set (request) switch is judged (P
8), if the set switch is ON, sets the vehicle speed at that time as the target vehicle speed V _s (P9), the throttle opening T to the throttle opening degree at that time the target vehicle speed V _s
It is stored as the initial value of _T (P10), the flag "CRUISE" indicating the constant speed running state is set to "1", and the flag "ACCEL" indicating the accelerator interlocking control during constant speed running is cleared to "0". (P11). If the set switch is OFF in P8, it is determined whether or not the vehicle is in the constant speed running state depending on whether the flag "CRUISE" is "1" (P
12) If the vehicle is not in the constant speed traveling state, the process ends. If it is in the constant speed traveling state, it is determined whether or not the accelerator pedal interlocking control is being performed by the flag "ACCEL" (P13).

When the accelerator pedal interlocking control is not being performed, the throttle opening or the throttle opening estimated value T _A which changes in conjunction with the accelerator pedal is compared with the throttle opening T _T for achieving the target vehicle speed V _S at P14. and, (when _{T a>} T T) when towards the throttle opening by depression of the accelerator pedal is large, set to "1" to the flag "ACCEL" to transition to the accelerator pedal interlocking control (P1
5) and ends. Here, the flag “ACCEL” is “1”
During this period, the constant speed traveling control is temporarily canceled, and the vehicle is controlled by the normal throttle valve control linked with the accelerator pedal depression amount. On the other hand, when the throttle opening for achieving the target vehicle speed V _S is larger, it is determined whether or not the control cycle is reached (P18). At this time, the target vehicle speed V _S and the current vehicle speed V _V are compared (P1
9), if the deviation ΔV is zero or within the specified range, P
At 12, the control amount as it is is output to the actuator, and Δ
If V ≠ 0 or outside the specified range, the control amount of the actuator is calculated (P21), the control amount is output to the actuator (P22), and the process ends.

At P13, the flag "ACCEL" is set to "1".
If the accelerator pedal interlock control is in progress, the accelerator pedal
Dynamically changing throttle opening or estimation of throttle opening
Value T _ATo the target vehicle speed_TYo
Smaller by α (T_T-Α) (P16), vehicle speed
Slows down to T_AWhen becomes smaller, the flag "ACCEL"
Is cleared to "0" to return to constant speed running (P17).

As described above, after the accelerator pedal is depressed to increase the speed during the constant speed running control and the accelerator pedal interlocking control is started, the throttle opening is lower than the value originally stored for the constant speed running. compared with the _(T T -α), returns from smaller than the cruise control. As a result, as shown by the thick solid line in FIG. 3, the accelerator pedal interlocking period during deceleration becomes longer than in the conventional method, and the throttle valve opening becomes lower than the target opening during the period of t _A. Therefore, it is possible to control the actuator in consideration of the response delay of the vehicle speed. As a result, the change in the actual vehicle speed changes from the conventional movement shown by the dotted line to the solid line, the convergence time to the target vehicle speed is shortened, and a sense of deceleration adapted to the driver's sense can be provided.

The calculation of the control amount to the actuator in P21 is based on the characteristics shown in FIGS. 4 and 5 if the acceleration or deceleration request is made by the operation of the speed increasing switch or the decelerating switch during the constant speed running control. , P1 is read by reading a value previously stored in the data table as a value corresponding to the running resistance calculated at P1 and the current opening degree of the throttle valve. By changing the control amount according to the running state in this way, it is possible to provide the feeling of acceleration / deceleration as requested by the driver. Each of the characteristics shown in FIGS. 4 and 5 may be a straight line such as a solid line, or may be a curve such as a dashed line. These characteristics are experimentally determined. In addition, if it is normal constant-speed traveling control, P19
Feedback control is performed using the deviation (ΔV) calculated in step 1 to calculate the control amount. At this time, of course, it is also possible to correct the calculated actuator control amount by applying the characteristic shown in FIG.

The control cycle of the actuator at P2 may be set, for example, by reading from a value stored in advance in the data table as a value corresponding to the running resistance calculated at P1, or P1 is used. It may be calculated by calculation. The control cycle may be changed stepwise depending on the magnitude of the running resistance as shown by the solid line in FIG. 6, or may be changed in a curve as shown by the alternate long and short dash line. A state where the traveling resistance is small corresponds to a state where the vehicle is traveling downhill, and a state where the traveling resistance is large corresponds to a state where the vehicle is traveling uphill, for example. When trying to run at a constant speed with a low or high running resistance, the vehicle speed easily changes. According to the present invention, when the traveling resistance is small or large, the control cycle is shortened according to the traveling resistance to frequently correct the control amount to the actuator, so that stable constant speed traveling can be performed. When the flag "CRUISE" is "1", that is, when the vehicle is traveling at a constant speed, idling determination is not performed.

[0019]

According to the present invention, the control cycle of the actuator for converging the actual vehicle speed to the target vehicle speed is changed according to the running resistance, so that the vehicle speed is further stabilized at a certain running resistance. When the running resistance changes, the accuracy of convergence to the target vehicle speed can be improved. Further, by changing the control amount to the actuator according to the current traveling state in response to the acceleration / deceleration request during constant speed traveling, it is possible to obtain the feeling of acceleration / deceleration as requested by the driver. Furthermore, the throttle valve opening based on the accelerator pedal operation amount is compared with the throttle valve opening for achieving the target vehicle speed to switch between the accelerator pedal interlocking acceleration request and the constant speed running control. When returning to the travel control, the throttle opening that should be compared with the opening of the throttle valve according to the operation amount of the accelerator pedal is set to a smaller opening than the throttle opening for achieving the target vehicle speed, thereby improving the controllability of the actuator. It is possible to provide a feeling of deceleration adapted to the driver's feeling.

[Brief description of drawings]

FIG. 1 is a functional block diagram of a constant speed traveling device according to the present invention.

FIG. 2 is a flowchart showing an example of constant speed traveling control.

FIG. 3 is a diagram illustrating a relationship between a throttle valve opening and a vehicle speed.

FIG. 4 is a diagram showing the relationship between running resistance and actuator control amount.

FIG. 5 is a diagram showing a relationship between a current throttle valve opening and an actuator control amount.

FIG. 6 is a diagram showing a relationship between running resistance and a control cycle.

[Description of Reference Signs] 1 ... Vehicle speed detecting means, 2 ... Target vehicle speed change commanding means, 3 ... Accelerator pedal operation amount detecting means, 4 ... Actuator, 5
... Throttle valve, 6 ... Throttle valve opening detection means, 7 ... Vehicle speed control means

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Matsuo Amano 2520 Takaba, Katsuta-shi, Ibaraki Prefecture Hitachi Ltd. Automotive Equipment Division

Claims (4)

[Claims] 1. Vehicle speed detection means for detecting an actual vehicle speed,
Control of a means for setting a target vehicle speed, an actuator for controlling the opening of a throttle valve, a control means for controlling the actuator, a running resistance calculation means for calculating a running resistance of the vehicle, and a control means for controlling the actuator. A control cycle changing means for changing the cycle, the control means controls the actuator so that the actual vehicle speed is maintained at the target vehicle speed, and the control cycle changing means travels calculated by the running resistance calculating means. A constant speed traveling device for an automobile, characterized in that a control cycle is changed according to resistance. 2. A target vehicle speed change command means for instructing a change of a target vehicle speed, a means for detecting an opening of a throttle valve, and an acceleration / deceleration amount change means, wherein the acceleration / deceleration amount change means is a target vehicle speed change. 2. The constant speed traveling device for an automobile according to claim 1, wherein the control amount of the control means based on the instruction of the command means is changed according to the traveling resistance or the current opening degree of the throttle valve. 3. A means for storing a throttle valve opening degree according to a target vehicle speed, a means for obtaining a throttle valve opening degree according to an accelerator pedal operation amount, and a throttle valve opening degree and a target according to an accelerator pedal operation amount. The determination means further includes a determination means for comparing the throttle valve opening according to the vehicle speed to determine whether to perform constant speed traveling control or accelerator pedal interlocking control, the determination means from the accelerator pedal interlocking control to the constant speed traveling control. The throttle opening to be compared with the opening of the throttle valve according to the operation amount of the accelerator pedal when returning to step 3 is set to an opening smaller than the stored opening. High-speed traveling device. 4. An idling judging means for judging an idling state of the engine using an operation amount of an accelerator pedal is further included, and the judgment result by the idling judging means is invalidated when the vehicle is in a constant speed traveling control state. The constant speed traveling device for an automobile according to claim 1, 2, or 3.