JP3204033B2 - Auto cruise control method - Google Patents

Abstract

PURPOSE: To eliminate an uncomfortable feeling due to a vehicle speed deviation by detecting an accelerating condition of a vehicle after an accelerator pedal is operated and this operation of the accelerator pedal is released and controlling an action of an auxiliary brake on the basis of an auxiliary control mode when a vehicle is accelerated. CONSTITUTION: When a vehicle is accelerated even after an accelerator pedal, which is once actuated, is returned, auxiliary brake control based on a vehicle speed deviation is not carried out, but a present mode for an auxiliary brake 11 is increased by one level by means of an auxiliary control mode, and execution of auxiliary brake control is given priority, and then, the mode for the auxiliary brake 11 is sequently increased until the present vehicle speed lowered below the target vehicle speed. Therefore, no abrupt braking force is generated if a vehicle speed deviation is large. If it is determined that the present vehicle speed lowered below the target vehicle speed (S6), an ACC flag is set to 0 in a step S7 (S7), and auxiliary brake control based on the vehicle speed deviation is carried out on the basis of an auxiliary brake operation controlling mode (S10).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic cruise control method for a vehicle accompanied by an auxiliary brake operation control.

[0002]

2. Description of the Related Art In general, a constant speed traveling device (auto cruise device) for a vehicle adjusts the output of an engine based on a vehicle speed deviation which is a deviation between an actual vehicle speed of the vehicle and a set vehicle speed. Is to maintain. In this auto cruise device, when the accelerator pedal is depressed after the accelerator pedal is depressed once during auto cruise traveling and then the accelerator pedal is released, the vehicle travels in the engine brake state and the vehicle speed is returned to the set vehicle speed.

On the other hand, as disclosed in Japanese Utility Model Laid-Open Publication No. 4-65624, there is known an automatic cruise system which includes an operation control of an auxiliary brake. This is to use control of the fuel supply amount and braking control of an exhaust brake, a retarder, and the like when the vehicle travels at a constant speed. By using an auto cruise system with operation control of the auxiliary brake, it is difficult to control the fuel supply amount at a constant speed.For example, by controlling the operation of the auxiliary brake even on a downhill, the vehicle speed can be increased. It is possible to drive at a constant speed while suppressing it.

[0004]

In a conventional auto-cruise system with operation control of an auxiliary brake, for example, the accelerator pedal is returned after the accelerator pedal is depressed and accelerated for overtaking during downhill traveling during auto-cruising. Then, the auxiliary brake is actuated in accordance with the vehicle speed deviation, and the vehicle travels in a braking state by the auxiliary brake to return the vehicle speed to the set vehicle speed. However, depending on the condition of acceleration or the road condition after acceleration, there is a possibility that the vehicle speed deviation becomes large and a sudden braking force is generated, and there is a possibility that the driving feeling deteriorates and the driver feels strange. Further, since the auxiliary brake is operated in accordance with the vehicle speed deviation, even when the vehicle is in a deceleration state, if the vehicle speed deviation exists, the auxiliary brake is operated, which may give a driver a sense of incongruity. there were.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide an automatic cruise control method for activating an auxiliary brake in a state in which a driver's discomfort is reduced even when a vehicle speed deviation occurs during auto cruise control. Aim.

[0006]

Means for Solving the Problems] auto cruise control method of the present invention for achieving the above object, the eyes of the actual vehicle speed
Use the auxiliary brake to maintain the set speed according to the target speed.
In the vehicle auto cruise control method including a first brake control for adjusting a braking force , the first brake control
A second brake that independently adjusts the braking force of the auxiliary brake
The vehicle is in an acceleration state when it is detected that the operation of the accelerator pedal is released after the accelerator pedal is operated during the auto cruise control.
In this case, the acceleration state is decelerated by the second brake control.
Increase the braking force of the auxiliary brake step by step until the
Until the actual vehicle speed reaches the set vehicle speed.
, The braking by the second brake control is continued,
Both are decelerating and the current vehicle speed exceeds the target vehicle speed
Performing the second brake control if
And the first brake control is released .

[0007] The auxiliary brake is used to determine the actual vehicle speed.
And a vehicle speed deviation which is a difference between the set vehicle speed and the target vehicle speed.
The braking force increases as the vehicle speed deviation increases.
It is characterized in that the braking force is set such that: Also,
The auxiliary brake is set in advance according to the vehicle speed deviation.
It has a plurality of levels of braking force .

[0008]

When the operation of the accelerator pedal is released after the operation of the accelerator pedal and the vehicle is in an accelerating state, the operation control of the auxiliary brake is executed by the second brake control to perform the auto cruise control.

Also, when the vehicle is in an acceleration state and the second brake
When executing the operation control of the auxiliary brake by the key control ,
The braking force generated by the auxiliary brake stepwise strongly. Also,
The operation control of the first brake is executed when the vehicle speed of the vehicle exceeds a set vehicle speed according to the target vehicle speed. Further, the auxiliary brake can provide a plurality of levels of braking force according to the vehicle speed deviation. Preferably, the operation control of the auxiliary brake by the second brake control is executed prior to the operation control of the auxiliary brake by the first brake control.

[0010]

FIG. 1 shows a schematic block diagram of an auto cruise apparatus for implementing an auto cruise control method according to one embodiment of the present invention. FIG. 2 is a flowchart of an automatic cruise control method according to an embodiment of the present invention, and FIG. 3 shows an example of an operation sequence of an auxiliary brake.

Referring to FIG. 1, a schematic configuration of the auto cruise device will be described. An auto cruise main switch 2 is connected to a control unit 1 of a vehicle such as a truck, and a signal for executing auto cruise control is input to the control unit 1 by operating the main switch 2. In addition, a set switch 3 and a resume switch 4 are connected to the control unit 1. The set switch 3 is used to set the auto cruise vehicle speed and decrease the auto cruise vehicle speed, and the resume switch 4 is used to return from the temporary cancellation of the auto cruise and increase the auto cruise vehicle speed.

The control unit 1 is connected to an auto cruise release switch 5. The auto cruise release switch 5 is closed by a clutch operation signal or a transmission neutral signal.

The control unit 1 is connected with an accelerator switch 6 for detecting the operation of the accelerator pedal and a stop lamp switch 7 linked to the operation of the foot brake, and controls the operation signal of the accelerator pedal and the operation signal of the foot brake. Input to unit 1. The control unit 1 includes a vehicle speed sensor 8.
The vehicle speed signal is input from the vehicle and the set vehicle speed is compared with the current vehicle speed.

The control unit 1 turns on a cruise lamp 9 during auto cruise control driving, and sends a signal to an electronic governor 10 of a diesel engine (not shown) to increase or decrease the amount of fuel supplied to the diesel engine.
Control is performed to maintain the vehicle speed at the set vehicle speed. When the vehicle speed exceeds the set vehicle speed while the engine brake is operating, the control unit 1 controls the operation of the auxiliary brake 11 so that the actual vehicle speed approaches the set vehicle speed.

The auxiliary brake 11 includes an exhaust brake 12, a compression-release type engine brake auxiliary device 13 and a first
It comprises a stage retarder 14, a second stage retarder 15 and a third stage retarder 16. The exhaust brake 12 obtains a braking force by the flow resistance of the exhaust according to the restriction of the exhaust pipe, and the compression-pressure releasing engine brake auxiliary device 13 includes, for example, a third engine provided in an appropriate engine cylinder. The braking force is obtained by opening the valve from the compression stroke to the expansion stroke and weakening the downward force of the piston. First
The stage retarder 14, the second stage retarder 15, and the third stage retarder 16, for example, change the blade angle of the stator in the fluid retarder to adjust the flow rate of the retarder and increase the rotational resistance of the propeller shaft to increase the braking force. What you get. In addition, as the retarder, an electric resistance type or the like may be used in addition to the fluid type, and the retarder is not limited to the fluid type.

As shown in FIG. 3, the auxiliary brake 11
As the vehicle speed deviation, which is the deviation between the actual vehicle speed and the set vehicle speed, increases, the exhaust brake 12, the compression-release type engine brake auxiliary device 13, the first-stage retarder 14, the second-stage retarder 15, and the third stage The retarders 16 are additionally operated in sequence to increase the braking force. Conversely, as the deviation between the actual vehicle speed and the set vehicle speed decreases, the respective operations are released in the reverse order to the above, and the braking force decreases. That is, the auxiliary brake 11 can obtain a plurality of levels of braking force according to the vehicle speed deviation. The order of operation and release of the operation of the auxiliary brake 11 is appropriately changed, and the means and number of the auxiliary brake 11 are variously changed.

When the vehicle reaches a desired speed after the main switch 2 is closed while the vehicle is running, the vehicle speed at this time is set as a set vehicle speed (target vehicle speed) by closing the set switch 3. Control is started. When the auto cruise control is started, the output of the diesel engine is adjusted by the control of the electronic governor 10 by the control unit 1, and the current vehicle speed Vh is maintained at the set target vehicle speed Vo. Note that the target vehicle speed Vo is not limited to the vehicle speed when the vehicle reaches the desired speed, that is, the target vehicle speed itself, as long as it is a predetermined value set according to the desired vehicle speed.

For example, if the vehicle runs downhill during execution of the auto cruise control, the vehicle speed increases even when the diesel engine is in the engine braking state. in this case,
First brake control of the control unit 1 (hereinafter referred to as supplementary
The auxiliary brake 11 is operated in the order described above according to the vehicle speed deviation by the auxiliary brake operation control mode, and the braking force is applied to maintain the current vehicle speed Vh at the target vehicle speed Vo (auxiliary brake control). . Further, the control unit 1 performs the second brake control (hereinafter referred to as the second brake control) for performing the auxiliary brake control in a mode different from the auxiliary brake operation control mode.
(Hereinafter referred to as an auxiliary control mode) . The control when the accelerator pedal is depressed for overtaking or the like during execution of the auto cruise control with the auxiliary brake control will be described with reference to FIG.

As shown in FIG. 2, during the auto cruise control, it is determined in step S1 whether or not the accelerator pedal is depressed based on the signal of the accelerator switch 6. If the accelerator pedal is depressed, the operation proceeds to step S2. The flag (ACC flag) is set to 1 and step S3
Then, the auxiliary brake control in the auxiliary brake operation control mode is released. If it is determined in step S1 that the accelerator pedal has not been depressed, the process proceeds to step S4.
It is determined whether the C flag is 1 or not. If the ACC flag is not 1, that is, if the ACC flag is 0 and the state where the accelerator pedal is not depressed continues, the process proceeds to step S10, and the auxiliary brake is performed. The auxiliary brake control is executed in the operation control mode.

If it is determined in step S4 that the ACC flag is 1, that is, if the accelerator pedal once depressed is released, it is determined in step S5 whether the vehicle is in an acceleration state. If it is determined in step S5 that the vehicle is not in an acceleration state, that is, the vehicle is in a deceleration state, the current vehicle speed Vh is compared with the target vehicle speed Vo in step S6. If it is determined in step S6 that the current vehicle speed Vh is higher than the target vehicle speed Vo, the vehicle is in a deceleration state, so that even if the current vehicle speed Vh is higher than the target vehicle speed Vo, in step S3 the auxiliary brake by the auxiliary brake operation control mode is set. Release control.

On the other hand, if it is determined in step S5 that the vehicle is accelerating after the accelerator pedal once depressed is released, for example, the accelerator pedal is depressed for overtaking while the vehicle is traveling downhill. When the downhill continues even after the overtaking is completed, the auxiliary brake control in the auxiliary control mode is executed in step S8. The auxiliary brake control in the auxiliary control mode is to increase the current mode (operation sequence shown in FIG. 3) of the auxiliary brake 11 by one step. For example, the current mode is the auxiliary brake control using only the exhaust brake 12 in the figure. At times, the auxiliary brake control by the exhaust brake 12 in the mode of the auxiliary brake 11 and the compression-pressure releasing type engine brake auxiliary device 13 is executed.

That is, when the vehicle is in an accelerated state after the accelerator pedal once depressed is released, the auxiliary control mode is not executed by the auxiliary control mode without executing the auxiliary brake control (auxiliary brake operation control mode) based on the vehicle speed deviation. The mode of the auxiliary brake 11 is increased by one step, and the auxiliary brake control is executed with priority, and the mode of the auxiliary brake 11 is sequentially increased up to in FIG. 3 until the current vehicle speed Vh falls below the target vehicle speed Vo. Therefore, even when the vehicle speed deviation is large, no sudden braking force is generated.

If it is determined in step S6 that the current vehicle speed Vh has become equal to or less than the target vehicle speed Vo, the ACC flag is set to 0 in step S7, and the process proceeds to step S10. Execute control.

As described above, when the vehicle is accelerating when the accelerator pedal once depressed is released during the auto cruise traveling with the operation of the auxiliary brake 11, the vehicle speed is controlled by the auxiliary brake operation control mode. Auxiliary brake control based on the deviation is not executed, and the current mode of the auxiliary brake 11 is increased by one step depending on the acceleration state, so that the auxiliary brake control is executed. Will not occur. For example,
If the accelerator pedal is depressed for overtaking while the vehicle is traveling on a downhill and the vehicle continues to accelerate downhill after overtaking is completed, the auxiliary brake 11 is operated based on the vehicle speed deviation. In such a case, a sudden braking force acts instantaneously, and the driving feeling deteriorates. However, by executing the auxiliary brake control in the auxiliary control mode, a sudden braking force does not work and smooth braking can be performed. In addition, the auxiliary brake control in the auxiliary control mode can be executed without adding a special device, so that the cost does not increase.

[0025]

Auto cruise control method of the present invention exhibits, when it becomes a situation where the vehicle is accelerating at once depressed the accelerator pedal during the operation of auxiliary brake is returned, the second
Since the operation control of the auxiliary brake is executed by the brake control , the auxiliary brake is not operated when the vehicle is being decelerated even if a vehicle speed deviation occurs, so that useless operation is prevented. Further, in the second brake control , the braking force by the auxiliary brake is stepwise increased, so that even if a large vehicle speed deviation occurs, there is no possibility that a sudden braking force is applied, and smooth braking can be performed. As a result, during auto cruise control with the operation of the auxiliary brake, it is possible to operate the auxiliary brake with less driver discomfort even if a vehicle speed deviation occurs, improving driving feeling and improving safety Is improved.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram of an auto cruise device that implements an auto cruise control method according to one embodiment of the present invention.

FIG. 2 is a flowchart of an auto cruise control method.

FIG. 3 is an explanatory diagram of an operation sequence of an auxiliary brake.

[Explanation of symbols]

 Reference Signs List 1 control unit 2 main switch for auto cruise 3 set switch 4 resume switch 5 auto cruise release switch 6 accelerator switch 7 stop lamp switch 8 vehicle speed sensor 9 cruise lamp 10 electronic governor 11 auxiliary brake 12 exhaust brake 13 compression pressure release type engine brake auxiliary Apparatus 14 First stage retarder 15 Second stage retarder 16 Third stage retarder

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-62-277827 (JP, A) JP-A-62-122830 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B60K 31/00 B60K 41/20 B60T 8/32 F02D 9/06 F02D 13/04

Claims (3)

(57) [Claims] An actual vehicle speed is set according to a target vehicle speed.
The first brake that adjusts the braking force of the auxiliary brake to maintain
In an automatic cruise control method for a vehicle with rake control , the control of the auxiliary brake is performed independently of the first brake control.
A second brake control for adjusting a braking force is provided to detect that the operation of the accelerator pedal is released after the accelerator pedal is operated during the auto cruise control.
When the vehicle is in an accelerating state,
(2) Until the acceleration state changes to the deceleration state by the brake control
Increases the braking force of the auxiliary brake in stages and
Until the current vehicle speed reaches the set vehicle speed, the second
Brake control, the vehicle is in a deceleration state, and the current vehicle speed is lower than the target vehicle speed.
If so, the second brake control is executed.
An automatic cruise control method characterized in that the first brake control is released without performing the control. 2. The vehicle according to claim 1, wherein said auxiliary brake is adapted to control an actual vehicle speed and said vehicle speed.
According to the vehicle speed deviation that is the difference from the set vehicle speed according to the target vehicle speed
So that the braking force increases as the vehicle speed deviation increases.
2. A braking force is set on the vehicle.
Automatic cruise control method of. 3. The vehicle according to claim 2, wherein the auxiliary brake responds to the vehicle speed deviation.
That it has the braking force of multiple stages set in advance
The auto cruise control method according to claim 2, wherein