JP3133391B2 - Vehicle constant speed traveling device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a constant speed traveling device for a vehicle.

[0002]

2. Description of the Related Art In a constant-speed traveling apparatus which performs control such that the actual vehicle speed of a vehicle, that is, the actual vehicle speed, becomes a predetermined set vehicle speed, in order to set the actual vehicle speed to the set vehicle speed, an intake air amount of an engine, that is, a throttle valve is set. Control is generally performed (see Japanese Utility Model Application Laid-Open No. 62-8126).

[0003]

Incidentally, recent engines have been increasing their output (increased torque) due to the tendency of increasing the displacement. In such a high-output engine, even a slight change in the throttle valve causes a large change in the engine torque. From such a relationship, even a slight change in the throttle opening during constant-speed running causes the actual vehicle speed to fluctuate considerably, and tends to cause problems in terms of convergence near the set vehicle speed, that is, smooth control. Become.
In particular, such a tendency becomes conspicuous at a low vehicle speed where the running resistance is small and the amount of change in torque with respect to the amount of change in the throttle opening is large. SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a constant-speed traveling device for a vehicle capable of performing smooth constant-speed traveling.

[0004]

In order to achieve the above-mentioned object, the present invention has a first configuration as follows. That is, vehicle speed detection means for detecting an actual vehicle speed, intake air amount control means for controlling an intake air amount of an engine such that the actual vehicle speed detected by the vehicle speed detection means becomes a predetermined vehicle speed, and Means for controlling the air-fuel ratio of the air-fuel mixture supplied to the engine such that the actual vehicle speed detected by the means becomes a predetermined set vehicle speed; and the actual vehicle speed detected by the vehicle speed detection means being a predetermined switching vehicle speed. A first control mode in which control is performed only by the air-fuel ratio control means when the vehicle speed is lower than the second speed, and a control is performed only by the intake air amount control means when the actual vehicle speed is higher than the switching vehicle speed. And control mode switching means serving as a control mode.

[0005] With this configuration, at low vehicle speeds, the vehicle is driven at a constant speed by air-fuel ratio control capable of finely adjusting the torque, thereby preventing a large fluctuation in the actual vehicle speed and providing a smooth constant speed. You can drive. Then, at a high vehicle speed at which the running resistance increases, it is possible to reliably converge to the set vehicle speed by the intake air amount control. In order to prevent hunting of switching between the first control mode and the second control mode, it is preferable that the switching has hysteresis.

[0006] Further, the present invention provides, as a second configuration thereof,
It is as follows. That is, vehicle speed detection means for detecting an actual vehicle speed, intake air amount control means for controlling an intake air amount of an engine such that the actual vehicle speed detected by the vehicle speed detection means becomes a predetermined vehicle speed, and Means for controlling the air-fuel ratio of the air-fuel mixture supplied to the engine such that the actual vehicle speed detected by the means becomes a predetermined set vehicle speed;
At a low vehicle speed lower than the switching vehicle speed, a first control mode in which control is performed only by the air-fuel ratio control means, wherein the actual vehicle speed is higher than a second switching vehicle speed set as a vehicle speed higher than the first switching vehicle speed In some cases, a second control mode is executed in which control is performed only by the intake air amount control means. When the actual vehicle speed is in a range between the first switching vehicle speed and the second switching vehicle speed, the intake air amount control means and the air-fuel ratio control are performed. A control mode switching means for performing both controls of the control means and the control means; and in the third control mode, as the actual vehicle speed increases, the control amount of the intake air amount control means increases and the air-fuel ratio increases. Control amount changing means for reducing the control amount of the control means.

With such a configuration, in addition to the effect of the first configuration, the connection between the first control mode and the second control mode can be smoothly performed.

According to another aspect of the present invention, the first
Instead of the air-fuel ratio control in the second configuration or the second configuration, an ignition timing control may be performed. Also in this case, the same effect as in the first configuration or the second configuration can be obtained. Further, according to the present invention, when the actual vehicle speed does not converge around the set vehicle speed, the second control mode, that is, the intake air amount excellent in responsiveness, is preferentially set when the actual vehicle speed does not converge near the set vehicle speed. By adopting the control mode by the control, the actual vehicle speed can be quickly approached to the set vehicle speed.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the accompanying drawings. In FIG. 1, reference numeral 1 denotes an Otto type engine. The output (generated torque) of the engine 1 is transmitted via a torque converter 2, an automatic transmission 3, and a propeller shaft 4 to left and right driving wheels (not shown). Is transmitted to

A throttle valve 6 and a fuel injection valve 7 are disposed in an intake passage 5 of the engine 1. By adjusting the opening of the throttle valve 6, the amount of intake air is adjusted and the output of the engine 1 is adjusted. Further, by adjusting the amount of fuel injected from the fuel injection valve 7, the air-fuel ratio of the air-fuel mixture is adjusted, and the output of the engine 1 is adjusted.

The mixture supplied to the engine 1 is ignited by a spark plug 10 and the ignition timing is adjusted by an igniter 11. Further, an exhaust passage 8 of the engine 1 is provided with an air-fuel ratio sensor 9 for generating a linear output signal according to the oxygen concentration in the exhaust gas.

U1 and U2 are control units each constructed using a microcomputer. The control unit U1 controls the fuel injection valve 7 to control the fuel injection amount, that is, the air-fuel ratio, and controls the igniter 11 to control the ignition timing.

The control unit U2 is for performing constant speed traveling control. Signals from sensors or switches S1 to S3 and 22 to 26 are input to the control unit U2. The sensor S1 is a vehicle speed sensor that detects the actual vehicle speed of the vehicle, that is, the actual vehicle speed. The switch S2 is an accelerator switch that is turned on when the accelerator is fully closed. The switch S3 is a brake switch that is turned on when the brake is depressed. Sensor 22
Is a throttle sensor for detecting the opening of the throttle valve 6.

The switches 23 to 26 are switches operated at a constant speed which are manually operated by the driver. Among them, the switch 23 is a main switch for selecting the constant speed traveling control. The switch 24 is a resume switch for resuming the constant speed traveling control at the set vehicle speed before the suspension from the state where the constant speed traveling is suspended. The switch 25 is a cost switch for reducing the set vehicle speed. The switch 2 is a set switch for starting constant-speed running control and increasing the set vehicle speed.

The output from the control unit U2 is to the actuator 21 and the control unit U1. The actuator 21 drives the throttle valve 6, and is constituted by, for example, a step motor. Control unit U
The output signal from 2 to U1 is for operating the control unit U1 so that a predetermined air-fuel ratio or ignition timing for constant-speed running is obtained.

Next, the control contents of the control unit U2 will be described with reference to the flowcharts shown in FIG.
In the following description, P indicates a step. 2 and 3 show the entire flow of the constant speed traveling control. First, at P1 in FIG. 2, a signal from each sensor and an operation state of each switch are input. At P2, it is determined whether or not the main switch 23 is on. . If the determination in P2 is NO, the constant speed traveling control is unnecessary, so
It returns to P1 as it is.

If YES in P2, it is determined in P3 whether the brake switch S3 is ON, that is, whether the brake is depressed. . If the determination at P3 is YES, the set flag is set to 1 at P4 to return to indicate that the brake has been depressed, and then the operation is returned. If the determination in P3 is NO, it is determined in P5 whether the accelerator is fully closed, that is, whether the accelerator switch S2 is ON. . If the determination in P5 is NO, the vehicle is returned without any change because the vehicle is not traveling at a constant speed.

If YES in P5, it is determined in P6 whether the set switch 26 is ON. If the determination in P6 is YES, in P7,
The actual vehicle speed VSP detected by the vehicle speed sensor S1 is set as a set vehicle speed (target vehicle speed) SETV. Then
At P7, set switch 26 is ON for 0.5 seconds or more
It is determined whether or not the operation is continued. If the determination in P8 is NO, in P9, steady-state control of the constant-speed traveling control is performed so that the set vehicle speed SETV set in P7 is achieved.

If the determination in P8 is YES, in P10, control is performed to increase the actual vehicle speed. As shown in FIG. 9, the control for increasing the actual vehicle speed is performed with the throttle having the vehicle speed set as a parameter as shown in FIG. Throttle valve 6 for opening
This is done by controlling As described above, while the set switch 26 is kept ON, P6, P7, P8, P
After repeating step 10, the actual vehicle speed is gradually increased, and the set switch 26 is turned off to shift from P8 to P9. At P9, the actual vehicle speed VSP at the time of being turned off becomes the set vehicle speed SETV. Is performed.

If the determination in P6 is NO, in P11, it is determined whether or not the cost switch 25 is ON. If the determination in P11 is YES, deceleration control is performed. This deceleration control is performed by fully closing the throttle valve 6, and the actual vehicle speed VS during deceleration.
P is set as the set vehicle speed SETV.

When the determination in P11 is NO, P2 in FIG.
At 1, it is determined whether or not the set flag is 1. If the determination in P21 is YES, in P22, it is determined whether or not the resume switch 24 is ON. If the determination in P22 is YES, in P23, the resume flag is set to 1, and then the flow shifts to P24.

At P24, the actual vehicle speed VSP becomes equal to the set vehicle speed S.
It is determined whether the value is greater than a value obtained by subtracting 2 km / h from the ETV. If the determination in P24 is NO, P25
, The above-described speed increase control is performed. Also, P24
If the determination is YES, the set flag is reset to 0 in P27, the resume flag is reset to 0, and the steady control described later is performed in P28.

If the determination in P22 is NO, in P26, it is determined whether or not the resume flag is 1. If the determination in P26 is YES, the aforementioned P24
To NO, and if NO in the determination of P26, the
Is performed.

FIG. 4 shows the contents of the steady control at P9 and P28 described above, and shows an example in which the air-fuel ratio control is performed at a low vehicle speed. First, in P31 and P32, the actual vehicle speed VSP is 2 k
It is determined whether or not the vehicle speed deviation is within the range of m / h. When the vehicle speed deviation is large, that is, when the determination of P31 or P32 is NO, in order to reduce the large deviation between the actual vehicle speed VSP and the set vehicle speed SETV with good response,
Throttle control described later, that is, intake air amount control is performed. Thereafter, in P39, the throttle flag is set to 1.

When the deviation between the actual vehicle speed VSP and the set vehicle speed SV is small, that is, the determinations of P31 and P32 are both YES.
In the case of, depending on the predetermined switching vehicle speed, it is determined whether to execute the constant speed traveling control by the throttle control in P38 or the constant speed traveling control by the air-fuel ratio control in P35 according to the processing of P33, P34, and P37. Is switched.

More specifically, at P34, it is determined whether or not the actual vehicle speed VSP is lower than 70 km / h.
If the determination in P33 is NO, the throttle control in P38 is performed. If YES in P33, P
At 34, it is determined whether the throttle flag is 1 or not. If the determination at P34 is NO, the air-fuel ratio control is executed at P35, and then the throttle flag is reset to 0 at P36.

If the determination in P34 is YES, the current control state is the throttle control state. At this time, in P37, it is determined whether or not the actual vehicle speed VSP is lower than 60 km / h. If the determination in P37 is NO, the throttle control is continued in P38, and if the determination in P37 is YES, the air-fuel ratio control is performed in P35. As described above, as the switching vehicle speed between the throttle control and the air-fuel ratio control, the upper limit switching vehicle speed (70 km
/ H) and the lower limit switching vehicle speed (60 km / h) (hysteresis setting) to prevent hunting of control mode switching.

FIG. 5 shows the details of the throttle control in the aforementioned P38. First, at P41, the vehicle speed deviation ENV is calculated by subtracting the actual vehicle speed VSP from the set vehicle speed SETV. Thereafter, at P42, based on the PI-PD control equation shown in the drawing, the current control amount T
G is calculated. In this equation, TG1 is the previous control amount, K
I is an integral coefficient, KP1 and KP2 are proportional coefficients, KD is a differential coefficient, ENV1 is a previous vehicle speed deviation, and EVN2 is a vehicle speed deviation two times before.

In P43, each numerical value is updated for the next calculation based on the PI-PD control formula. Next, P44
In, after the TG is set as the target throttle opening TH, the TH is output at P45 (the TH is output to the control unit U1, and the U1 executes the TH).

FIG. 6 shows the contents of the air-fuel ratio control at P35 described above. First, in P51, the difference ENV is calculated by subtracting the actual vehicle speed VSP from the set vehicle speed SETV. Thereafter, at P52, the current control amount AG is calculated based on the PI control formula shown in the figure. In this equation, AG1 is the previous control amount, KI is the integral coefficient, KP is the proportional coefficient, and ENV1 is the previous vehicle speed deviation.

At P53, each numerical value is updated for the next calculation based on the PI control formula. Next, in P54, after AG is set as the target air-fuel ratio AH,
Is output at the control unit U1 (A
H is output and U1 executes AH).

FIGS. 7 and 8 show another embodiment of the present invention, in which a first control mode using only the throttle control at a high vehicle speed and a second control mode using only the air-fuel ratio control at a low vehicle speed. In addition, the third control mode in which both controls are performed at the time of middle vehicle speed is switched.

First, when it is determined in steps P61 and P62 that the actual vehicle speed VSP is not within a range of 2 km / h from the set vehicle speed SETV, the throttle control is performed in step P67 (step P38). Same as control contents). If it is within the vehicle speed deviation of 2 km / h, it is determined in P63 whether or not the actual vehicle speed VSP is at a high vehicle speed greater than 80 km / h. . When the determination in P63 is YES, the throttle control is also performed in P67.

If the determination in P63 is NO, it is determined in P64 whether the actual vehicle speed VSP is lower than 60 km / h. . If the determination in P64 is YES,
In P65, air-fuel ratio control is performed. And P
When the determination in step 64 is NO, the switching control described later is performed in which both the throttle control and the air-fuel ratio control are performed.

FIG. 8 shows the contents of the aforementioned P66. First, a throttle control is performed in P71 and an air-fuel ratio control is performed in P72.
Up to the determination of AH, the operation is performed in exactly the same manner as in the case of FIGS. In P73, a weighting coefficient α for changing the control amount corresponding to the actual vehicle speed is read with reference to the map shown in FIG. This α is 1 when the actual vehicle speed is 60 km / h, 0 when the actual vehicle speed is 80 km / h, and is 60 to 80 km / h.
Is gradually reduced as the actual vehicle speed increases.

In P74, the control amount T determined in P71
H is multiplied by (1−α) to correct the control amount TH, and the control amount AH is corrected by multiplying the control amount AH by α. That is, the control amount TH for throttle control is increased as the actual vehicle speed increases,
The control amount AH for air-fuel ratio control decreases as the actual vehicle speed increases. Then, in P75, TH and AH after the change in P74 are output.

In the above description, the case of the constant speed running by the throttle control and the air-fuel ratio control has been described. However, the ignition timing control may be performed instead of the air-fuel ratio control at P35 or P65 (ignition timing). The setting of the control amount is shown in FIG.
The method may be performed in the same manner as the setting of the air-fuel ratio control amount shown in (1).

[Brief description of the drawings]

FIG. 1 is an overall system diagram showing one embodiment of the present invention.

FIG. 2 is a flowchart showing a first control example of the present invention.
G.

FIG. 3 is a flowchart showing a first control example of the present invention.
G.

FIG. 4 is a flowchart showing a first control example of the present invention.
G.

FIG. 5 is a flowchart showing a first control example of the present invention.
G.

FIG. 6 is a flowchart showing a first control example of the present invention.
G.

FIG. 7 is a flowchart showing a second control example of the present invention.
G.

FIG. 8 is a flowchart showing a second control example of the present invention.
G.

FIG. 9 is a diagram showing a setting of a throttle opening corresponding to a vehicle speed at the time of speed increase control.

FIG. 10 is a diagram showing coefficients for performing a control amount change in a third control mode.

[Explanation of symbols]

 Reference Signs List 1 engine 6 throttle valve 7 fuel injection valve 10 spark plug 11 igniter 23 main switch 24 resume switch 25 cost switch 26 set switch U1, U2 control unit S1 vehicle speed sensor

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B60K 31/04 F02D 29/02 301

Claims (7)

(57) [Claims] A vehicle speed detecting means for detecting an actual vehicle speed; an intake air amount controlling means for controlling an intake air amount of an engine such that the actual vehicle speed detected by the vehicle speed detecting means is a predetermined set vehicle speed; Air-fuel ratio control means for controlling the air-fuel ratio of the air-fuel mixture supplied to the engine such that the actual vehicle speed detected by the vehicle speed detection means becomes a predetermined set vehicle speed; A first control mode in which control is performed only by the air-fuel ratio control means when the vehicle speed is lower than the switching vehicle speed, and control is performed only by the intake air amount control means when the actual vehicle speed is higher than the switching vehicle speed. And a control mode switching means as a second control mode to be performed. 2. The vehicle according to claim 1, wherein a hysteresis is set for switching between the first control mode and the second control mode.
Line device . 3. A vehicle speed detecting means for detecting an actual vehicle speed; an intake air amount controlling means for controlling an intake air amount of an engine such that the actual vehicle speed detected by the vehicle speed detecting device becomes a predetermined vehicle speed; Air-fuel ratio control means for controlling the air-fuel ratio of the air-fuel mixture supplied to the engine such that the actual vehicle speed detected by the vehicle speed detection means becomes a predetermined set vehicle speed; A first control mode in which control is performed only by the air-fuel ratio control means when the vehicle speed is lower than the first switching vehicle speed, and the second vehicle speed is set as a vehicle speed whose actual vehicle speed is higher than the first switching vehicle speed.
At a high vehicle speed higher than the switching vehicle speed, a second control mode in which only the intake air amount control means executes the control, and when the actual vehicle speed is in a range between the first switching vehicle speed and the second switching vehicle speed, the intake air A control mode switching unit that is a third control mode for executing both control of the amount control unit and the air-fuel ratio control unit; and in the third control mode, as the actual vehicle speed increases,
A control amount changing means for increasing a control amount of the intake air amount control means and decreasing a control amount of the air-fuel ratio control means. 4. A vehicle speed detecting means for detecting an actual vehicle speed, an intake air amount controlling means for controlling an intake air amount of an engine so that the actual vehicle speed detected by the vehicle speed detecting device becomes a predetermined vehicle speed, Ignition timing control means for controlling the ignition timing of the engine such that the actual vehicle speed detected by the vehicle speed detection means is a predetermined set vehicle speed; and the actual vehicle speed detected by the vehicle speed detection means is lower than a predetermined switching vehicle speed. A first control mode in which control is performed only by the ignition timing control means when the vehicle speed is low, and a second control mode in which control is performed only by the intake air amount control means when the actual vehicle speed is higher than the switching vehicle speed. A constant-speed traveling device for a vehicle, comprising: a control mode switching unit. 5. The vehicle according to claim 4, wherein hysteresis is set for switching between the first control mode and the second control mode.
Line device . 6. A vehicle speed detecting means for detecting an actual vehicle speed; an intake air amount controlling means for controlling an intake air amount of an engine such that the actual vehicle speed detected by the vehicle speed detecting device becomes a predetermined set vehicle speed; Ignition timing control means for controlling the ignition timing of the engine such that the actual vehicle speed detected by the vehicle speed detection means is a predetermined set vehicle speed; and the actual vehicle speed detected by the vehicle speed detection means is a predetermined first switching vehicle speed. When the vehicle speed is lower than the first switching mode, the control is performed only by the ignition timing control means. When the actual vehicle speed is higher than a second switching vehicle speed set as a vehicle speed higher than the first switching vehicle speed, the first control mode is set. A second control mode for executing control only by the intake air amount control means,
When the actual vehicle speed is in the range between the first switching vehicle speed and the second switching vehicle speed, the control mode switching means is a third control mode for executing both controls of the intake air amount control means and the ignition timing control means. In the third control mode, as the actual vehicle speed increases,
A control amount changing unit that increases a control amount of the intake air amount control unit and decreases a control amount of the ignition timing control unit. 7. The control system according to claim 1, wherein when the actual vehicle speed does not converge around the set vehicle speed, the second control mode is set prior to the control mode switching means. ,
A constant-speed traveling device for a vehicle, comprising: