JPH09169225A - Running control device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the sudden change of acceleration or deceleration due to the change of control mode by shifting a distance-between-vehicles mode to a constant speed mode via an acceleration/deceleration control mode. SOLUTION: An ECU 11 to which switches and sensors for detecting input driving state has a distance-between-vehicles mode which keeps the distance a vehicle and the one ahead at an aiming distance and a constant speed mode which keeps a vehicle speed at an aiming vehicle speed. The distance-between- vehicles control mode is shifted to the constant speed mode via an acceleration/ deceleration control mode: an aiming acceleration or deceleration is determined by product of a vehicle acceleration or deceleration and the rate of change of an aiming acceleration and the aiming acceleration or deceleration is corrected based on the deviation of an actual vehicle speed from a control speed calculated from the integral of the aiming acceleration or deceleration. When the deviation of the absolute value between the actual acceleration or deceleration and the corrected aiming acceleration or deceleration is less than a specified value, the mode is shifted to the constant speed mode.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention performs vehicle speed auto-cruise control for maintaining a host vehicle speed at a set vehicle speed designated by input of an auto-cruise set signal and inter-vehicle auto-cruise control for maintaining an appropriate inter-vehicle distance from a preceding vehicle. The present invention relates to a vehicle travel control device.

[0002]

2. Description of the Related Art A constant speed control mode (vehicle speed auto cruise control) for performing feedback control so as to keep the vehicle speed of a host vehicle at a set vehicle speed, and an inter-vehicle control mode for performing feedback control so as to maintain an appropriate inter-vehicle distance with respect to a vehicle ahead. As a conventional example of a vehicle traveling control device capable of switching (inter-vehicle automatic cruise control), for example, Japanese Patent Laid-Open No. 6-320987 is known. In such a conventional vehicle travel control device, the target vehicle loses sight due to a lane change or the like of the target vehicle while traveling in the inter-vehicle control mode in which the inter-vehicle distance from the preceding target vehicle is kept constant. There are cases.
Therefore, when the preceding vehicle is lost while traveling in the inter-vehicle distance control mode, it is set to shift to the constant speed control mode.

[0003]

It is conceivable to set the vehicle speed immediately before the driver loses sight of the traveling vehicle as the target vehicle speed in the constant speed control mode when shifting from the following distance control mode to the constant speed control mode. When the above-described transition control is executed, there is a problem that the acceleration / deceleration state of the vehicle changes, and the influence of the change control causes the passenger to feel uncomfortable. That is, as shown in FIG. 6, while traveling in the inter-vehicle distance control mode, the vehicle speed increases following the preceding vehicle as shown by the solid line, and the vehicle speed V increases at time t0.
If the preceding vehicle is lost at 1, the vehicle speed increasing / decreasing means of the vehicle immediately operates to maintain the vehicle speed V1. However, if the vehicle suddenly switches to the constant speed control mode during acceleration in the inter-vehicle distance control mode as described above, the vehicle speed may overshoot due to the response delay of the control system, and the acceleration / deceleration may change sharply, causing the driver to feel uncomfortable. was there. Even when the vehicle speed decelerates following the preceding vehicle as shown by the broken line, the acceleration / deceleration may also change sharply, which may give the driver discomfort.

Therefore, it is desired to eliminate a sudden change in the acceleration / deceleration at the time of switching the control mode in the vehicle travel control device capable of switching the traveling in the constant speed control mode or the inter-vehicle distance control mode. An object of the present invention is to provide a vehicle traveling control device capable of preventing a rapid change in acceleration / deceleration due to switching from vehicle-to-vehicle auto cruise to vehicle speed auto cruise.

[0005]

In order to achieve the above object, the present invention provides a vehicle-interval control mode for maintaining a vehicle-to-vehicle distance to a preceding vehicle at a target distance and a constant speed control mode for maintaining a vehicle speed at a target vehicle speed. In the vehicle travel control device capable of switching between and, the acceleration / deceleration control mode is passed through when the vehicle-to-vehicle distance control mode is switched to the constant speed control mode, and the vehicle acceleration / deceleration when the vehicle-to-vehicle distance control mode is canceled in the acceleration / deceleration control mode. The target acceleration / deceleration is sequentially set in accordance with the elapsed time after the suspension and the vehicle is configured to travel at the target acceleration / deceleration.

According to a second aspect of the present invention, in the vehicle travel control device according to the first aspect, the target acceleration / deceleration is set so that the vehicle speed converges to the target vehicle speed with the passage of time.

According to a third aspect of the present invention, in the vehicle running control device according to the first aspect, the target acceleration / deceleration is set so as to converge with the vehicle acceleration / deceleration when the inter-vehicle control mode is stopped and the elapsed time after the increase. It is characterized by being determined by the product of the target acceleration change rate.

According to a fourth aspect of the present invention, in the vehicle running control device according to the first aspect, in the acceleration / deceleration control mode,
The target acceleration / deceleration is corrected based on a deviation between the actual vehicle speed and the control speed calculated from the vehicle speed when the inter-vehicle control mode is stopped and the integrated value of the target acceleration / deceleration.

According to a fifth aspect of the present invention, in the vehicle running control device according to the first aspect, when the absolute value of the target acceleration / deceleration and the absolute value of the actual acceleration / deceleration are equal to or less than a predetermined value for a predetermined time or more, It is characterized in that the acceleration / deceleration control mode is shifted to the constant speed control mode.

According to a sixth aspect of the present invention, in the vehicle traveling control device according to the first aspect, when the preceding vehicle cannot be recognized while traveling in the inter-vehicle distance control mode, the constant control is performed via the acceleration / deceleration control mode. The present invention is characterized in that the speed is changed to the speed control mode, and the vehicle speed when the inter-vehicle distance control mode is stopped is set as the target vehicle speed.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a vehicular travel control device as an embodiment of the present invention. This vehicle running control device is attached to a diesel engine (hereinafter simply referred to as an engine) 1 of a vehicle and its power transmission system. In this engine 1, a clutch 2 and a transmission 3 are integrally and sequentially connected to a main body of the engine 1, and an output shaft of the transmission 3 is a drive wheel 6 via a peller shaft 4 and a differential 5.
Linked to In particular, a retarder 9 whose operation is controlled via an electromagnetic clutch is connected to the propeller shaft 4. A fuel injection pump 10 is provided on the side wall of the main body of the engine 1.
Is attached.

The fuel injection pump 10 is a well-known in-line injection pump, and a rack (not shown) is slid by an electronic governor 12 which receives a lever opening output corresponding to the fuel supply amount from the engine controller 11 to adjust the fuel injection amount. it can.
The exhaust system of the engine 1 is equipped with engine brake assisting means. The engine brake assisting means drives the shutter valve 26 provided in the exhaust passage R in the closing direction during engine braking to increase the exhaust pressure to increase the intake / exhaust work of the engine 1 and generate the absorb work. 16, the compression work is increased in the compression stroke of the engine, and the exhaust valve 27 described later is temporarily opened immediately after the compression stroke,
The compression opening type engine brake device 28 that releases the pressure in the cylinder to reduce the expansion work in the expansion stroke and sufficiently generate the absorption work in the compression / expansion stroke, and receives the rotational energy from the drive wheel 6 side to change this. It is composed of a retarder 9 that absorbs.

In place of the compression opening type engine braking device 28, a third valve (not shown) is temporarily opened immediately after the compression stroke to release the pressure in the cylinder and reduce the expansion work in the expansion stroke. It is also possible to use a third valve type compression opening type engine braking device that sufficiently generates absorption work in the compression / expansion stroke. Exhaust brake device 16
On the exhaust pipe 271 following the exhaust manifold 27 of the engine 1, a shutter valve 26, an actuator (not shown) for switching and driving the shutter valve to an open / close position, and an actuator switch for receiving a drive output for opening / closing operation from the drive circuit 116. The electromagnetic valve 17 for the engine and the engine controller 11 having the drive circuit 116 built therein.

In the exhaust brake device 16, the drive circuit 11 is operated when the engine controller 11 receives the exhaust switch signal EB and the accelerator switch signal AC and the exhaust switch 50 is ON and the accelerator switch 51 is OFF.
6. The normally open shutter valve 26 is closed via the solenoid valve 17, thereby causing a large amount of absorption work (negative work) over the intake stroke rather than the exhaust stroke. As shown in FIG. 3, the compression opening type engine braking device 28 is attached to an OHV type valve operating system. The engine 1 has an exhaust valve 43 in the combustion chamber 29.
(Two valves here) and an intake valve (not shown) are arranged, and a pair of exhaust valves 43 are opened and closed by the exhaust rocker arm 31 via the valve bridge 30. The other end of the exhaust rocker arm 31 is driven by an exhaust cam (not shown) via an exhaust side push rod (not shown).

The valve bridge 30 abuts on the upper end of the valve stem of one of the pair of exhaust valves 27, but here, the valve bridge 30 is slidably fitted in the through hole of the valve bridge 30. It abuts via the valve pin 32. The engine 1 has an oil passage forming body 3 on the cylinder head 33.
4 is integrally mounted, and a rocker cover (not shown) is mounted thereon. This oil passage forming body 34 is provided in each cylinder (1 in FIG. 3).
A master piston 37 that includes a slave piston 35 that faces the valve type pin 32 (only the cylinder is shown), and that drives the piston via a hydraulic fluid passage 36 of a closed circuit system;
A solenoid valve 39 and a control valve 40 for supplying a hydraulic pressure from a hydraulic pressure source P at a predetermined time via a distribution passage 38 are accommodated in the hydraulic oil passage 36.

Here, the slave piston 35 of one cylinder
The master piston 37 that drives the piston via the hydraulic oil passage 36 is arranged so as to face the intake rocker arm 31 ′ of another cylinder. In this case, the intake rocker arm 31 ′ of the other cylinder drives the slave piston 35 of the cylinder of 1 near the end of the compression stroke, and the exhaust valve 2 via the valve pin 32.
Open 7 Then, the master piston 37 is arranged at the end of the rocker arm 31 ′ facing the push rod 41, and the master piston 37 and the slave piston 35 of the first cylinder are communicated with each other through the hydraulic oil passage 36.

In this case, the solenoid valve 3 is not activated.
9 is turned off, the hydraulic pressure in the distribution passage 38 is removed to the drain side D, the control valve 40 descends, the hydraulic fluid passage 10 is opened, and the slave piston 35 is deactivated. On the other hand, at the time of driving, the solenoid valve 39 is turned on to communicate the hydraulic pressure source with the distribution passage 38, raise the control valve 40, and close the hydraulic fluid passage 36. Accordingly, when the master piston 37 is driven, the slave piston 35 is driven, and the valve pin 32 and the exhaust valve 27 operate in the valve opening direction. As a result, when the compression release type engine auxiliary braking device is driven, the high pressure gas in the cylinders is discharged near the end of the compression stroke of each cylinder to absorb the compression work,
The kinetic energy of the vehicle can be absorbed.

As shown in FIG. 1, the retarder 9 is connected to the propeller shaft 4 via an electromagnetic clutch (not shown). This electromagnetic clutch is a normally open clutch, and the drive circuit 11
When the clutch contact output from 7 is received, the rotation of the propeller shaft 4 is transmitted to the retarder 9, and this retarder 9 converts the rotational energy from the drive wheel 6 side into heat energy and absorbs it. Here, the engine controller 11 is mainly composed of a microcomputer, and includes a control circuit 111, a memory circuit 112, an input / output circuit 113, and four drive circuits 114-1.
17 and a power supply circuit 118.

The control circuit 111 receives various input information in accordance with the automatic cruise control routine shown in FIG. 5, and issues a control signal corresponding to the input information. The memory circuit 112 has a predetermined set value, an auto cruise control program shown in FIG. 2, an acceleration change rate map M-1 in FIG. 2, a corrected acceleration map M-2 for calculating a corrected acceleration A2 corresponding to the vehicle speed deviation ε, and others. The arithmetic expression and the like are stored. The acceleration change rate map M-1 in FIG. 2 is t (=
0) Each vehicle acceleration / deceleration _AF is the elapsed time t after the stop.
The target acceleration change rate A1 corresponding to each vehicle acceleration / deceleration _AF is a constant (0 to 0).
(Values within 1.0) are set as time-dependent change sequences.

That is, the target acceleration change rate A1 here is 1.0 at the time t (= 0) when the inter-vehicle distance control mode is stopped, and the larger the vehicle acceleration / deceleration _AF at that time is, the more the target acceleration change rate A becomes.
The convergence rate of the value of 1 is set low (convergence time is delayed). The corrected acceleration map M-2 in FIG. 2 sets the corrected acceleration A2 according to the vehicle speed deviation ε which is a value obtained by subtracting the actual vehicle speed V from the vehicle speed V _F at the time t (= 0) when the inter-vehicle distance control mode is stopped. The correction acceleration A2 is set so as to rapidly increase or decrease in a quadratic curve with respect to the vehicle speed deviation ε2.

The input / output circuit 113 receives various input information to be input and outputs various control signals in accordance with commands from the control circuit 111. This input / output circuit 113 is provided with an auto cruise set signal (hereinafter simply referred to as a set signal) C
A set switch 18 for outputting S, a resume switch 19 for issuing an acceleration command signal CR for returning the vehicle speed to the original auto cruise set speed after the setting is released and for starting a constant speed traveling, and a vehicle speed sensor 23 for outputting a vehicle speed signal V. , An inter-vehicle sensor 2 which outputs an inter-vehicle distance signal S _L between the preceding vehicle
4. An auto-cruise main switch 25 that outputs an auto-cruise ON signal SM and a plurality of release switches that respectively output a release signal for releasing the auto-cruise set are connected. The release switch here includes a stop lamp switch 20 that outputs a brake signal B, a clutch switch 21 that outputs a clutch engagement signal Sc, and a neutral signal S _{N of the} transmission 3.
The neutral switch 22 that outputs is used.

Further, the input / output circuit 113 has an auxiliary brake switch 42 mounted near the steering wheel.
Thus, the first and second auxiliary brake drive signals B1 and B2 are input. This auxiliary brake switch is a toggle switch, and outputs the first auxiliary brake drive signal B1 reaching the S1 position from the OFF position and the second auxiliary brake drive signal B2 reaching the S2 position, respectively. The power supply circuit 118 is a constant voltage circuit, and the main switch 13 is connected to the power supply 14 of the vehicle.
Connected through.

The first drive circuit 114 supplies a drive current to the electronic governor 12 according to the fuel injection amount signal from the input / output circuit 113.
To supply. The second drive circuit 115 outputs an ON output to the solenoid valve 39 in response to the compression release engine brake drive signal from the input / output circuit 113. Third drive circuit 11
Reference numeral 6 outputs an ON output to the solenoid valve 17 in response to the exhaust brake drive signal from the input / output circuit 113. Fourth drive circuit 11
Reference numeral 7 supplies clutch engagement output to the electromagnetic clutch 8 of the retarder 9 in response to the retarder brake drive signal from the input / output circuit 113. The engine controller 11 executes well-known engine control on the side of a main routine (not shown), and at the same time, executes control processing according to the auto cruise control routine shown in FIG.

The engine controller 11 has an inter-vehicle distance control mode for maintaining the inter-vehicle distance with the preceding vehicle at a target distance,
It has a function of executing a constant speed control mode for maintaining the vehicle speed at the target vehicle speed. In particular, during the transition from the headway distance control mode to the constant speed control mode, the vehicle goes through the acceleration / deceleration control mode, and in this acceleration / deceleration control mode, the target is set according to the vehicle acceleration / deceleration _AF when the headway distance control mode is stopped and the elapsed time after the stop. Acceleration / deceleration Aref is sequentially set and the vehicle is run at the same target acceleration / deceleration.

The engine controller 11 has the following functions. That is, to determine the target acceleration Aref by the product of the target jerk A ₁ that is configured to converge with increasing vehicle acceleration or deceleration A _F canceled after time in the distance control mode canceled. In the acceleration / deceleration control mode, a deviation ε between the control speed V ₁ and the actual vehicle speed V calculated from the vehicle speed V _F when the inter-vehicle distance control mode is stopped and the integrated value of the target acceleration / deceleration Aref.
Based on the above, the target acceleration / deceleration Aref is corrected. In this case, the absolute value of the corrected target acceleration / deceleration Aref 'and the actual acceleration / deceleration An
When the state in which the absolute value of is less than or equal to the predetermined value ΔVr continues for a predetermined time α or more, the acceleration / deceleration control mode is shifted to the constant speed control mode. Further, when the preceding vehicle cannot be recognized while traveling in the inter-vehicle distance control mode, the vehicle moves to the constant speed control mode via the acceleration / deceleration control mode, and the vehicle speed V _F when the inter-vehicle distance control mode is stopped is set as the target vehicle speed.

The operation of such a vehicle running control device is shown in FIG.
The automatic cruise control routine will be described. When the main switch 13 is turned on, the engine controller 1
1 executes a predetermined engine control main routine to continue traveling. During this period, when a signal indicating that the exhaust switch 50 is ON and the accelerator switch 51 is OFF is input, the engine controller 11 causes the exhaust brake device 16 to operate.
To the exhaust valve R by the shutter valve 26.
To increase the exhaust pressure to increase the negative work of the engine 1 and increase the action of the engine brake.

Further, when the auxiliary brake switch 42 is switched to the S1 position and the accelerator switch 51 is turned OFF while the first auxiliary brake drive signal B1 is input, the engine controller 11 causes the compression release type engine brake. It provides an output to solenoid valve 39 of device 28. As a result, the exhaust valve 43 immediately after the compression stroke is temporarily opened to absorb the compression work, and further the pressure in the cylinder is released to reduce the expansion work in the expansion stroke and sufficiently generate the absorption work in the compression / expansion stroke. Let Further, when the auxiliary brake switch 42 is switched to the S2 position and the signal of the accelerator switch 51 is input in the state where the second auxiliary brake drive signal B2 is input, the engine controller 11 causes the compression release type engine brake device 28 to operate. At the same time when the brake is operated, the clutch contact output is issued to the electromagnetic clutch (not shown) of the retarder 9. As a result, the drive wheels 6
Is transmitted to the retarder 9 via the propeller shaft 4 and the electromagnetic clutch, and the retarder 9 converts the rotational energy from the drive wheels 6 into heat energy and absorbs it.

Next, while the vehicle is traveling, the main switch 25 for automatic cruise sends an ON signal to the engine controller 11.
Inputting to starts an interrupt to the auto cruise control routine. In step s1, while the input signal CS of the cruise set switch 18 is not present, the process directly returns to the main routine, and when the input signal CS is input, Ye is first input.
If the process proceeds to the s side, the initial control is performed only in that case. That is, the set vehicle speed is stored and the vehicle speed control mode (constant speed control mode) is stored.
In order to keep the current vehicle speed V as it is,
The rack position corresponding to the injection amount according to the current vehicle speed V is calculated, and the electronic governor 12 is driven to maintain the initial rack position. This initial control is not performed in the next control cycle, and the process directly proceeds to step s2. Here, it is determined whether or not the vehicle speed control mode is in progress, and the process proceeds to step s3. Here, in the vehicle speed control mode, vehicle speed control is performed to eliminate the deviation between the current vehicle speed and the specified set vehicle speed V _S, and the process proceeds to step s4.

In this vehicle speed control mode, when the current vehicle speed falls below the set vehicle speed V _S , the fuel quantity signal output to the electronic governor 12 is increased and corrected, and when the current vehicle speed exceeds the set vehicle speed V _S , the fuel output to the electronic governor 12 is corrected. Correct the volume signal
Output each. Moreover, if the amount by which the current vehicle speed exceeds the set vehicle speed V _S exceeds the first set value, the exhaust brake device 16
The electromagnetic brake 17 to increase the effect of engine braking, and when the second set value is exceeded, the exhaust brake device 16
And the output to the solenoid valve 39 of the compression opening type engine braking device 28 to strengthen the braking force, and when the third set value is exceeded, the exhaust braking device 16 and the compression opening type engine braking device 28 are operated. At the same time, a clutch contact output is issued to an electromagnetic clutch (not shown) of the retarder 9 to further strengthen the braking force.

The control of the exhaust brake, the compression opening type engine brake, and the retarder when the cruise switch is turned on is automatically performed in addition to the control linked to the switch operation described above.

In step s4, the vehicle ahead is caught by the inter-vehicle distance sensor 24 during this vehicle speed control mode, and it is determined whether the inter-vehicle distance at that time is within the inter-vehicle automatic cruise range. If it is not, the control process in this control cycle is terminated and the process returns to the main routine or the like. Next, in step s2, it is determined that the vehicle speed control mode is not set, and when step s5 is reached, it is determined here whether or not the vehicle headway distance control mode is in effect. If the vehicle headway distance control is in progress, step s6 otherwise proceeds to step s11. When step s6 is reached during the inter-vehicle distance control mode, it is determined here whether the preceding vehicle is in the inter-vehicle automatic cruise range, that is, whether or not the preceding vehicle is being captured, and if so, the process proceeds to step s7, where the inter-vehicle distance is the set inter-vehicle distance. Control is performed in the inter-vehicle distance control mode so as to match the distance, and the process returns.

In this vehicle-to-vehicle distance control mode, the fuel amount signal output to the electronic governor 12 is increased and corrected when the captured vehicle interval is widened, and the fuel amount signal output to the electronic governor 12 is reduced and output when the captured vehicle interval is narrowed and output. . Moreover, under certain conditions when the amount of narrowing between the captured vehicles exceeds the first set value, an output is output to the electromagnetic valve 17 of the exhaust brake device 16 to increase the action of the engine brake, and when the second set value is exceeded, the exhaust brake device 16 is output. Output to the solenoid valve 39 of the compression opening type engine braking device 28 to strengthen the braking force, and when the third setting value is exceeded, outputs are output to the exhaust braking device 16 and the compression opening type engine braking device 28, respectively. At the same time, the clutch contact output is issued to the electromagnetic clutch of the retarder 9 to further enhance the braking force.

The control of these various auxiliary brakes is automatically performed separately from the switch operation, as in the case of the vehicle speed control described above.

Step s6 is reached during the headway distance control mode,
Here, if the preceding vehicle that is being captured loses sight of the preceding vehicle due to a lane change or the like, the process returns to the main routine through steps s8 to s10. Here, the vehicle-to-vehicle speed control transition flag is set, and then the vehicle acceleration / deceleration A _F immediately before the preceding vehicle is lost, that is, when the vehicle-interval control mode is stopped.
Is read as an initial value, and further, the vehicle speed V _F at the time of stopping the inter-vehicle distance control mode is read as an initial value. Step s5
If it is determined that the vehicle-to-vehicle speed control transition flag is set in the vehicle-interval control mode and the vehicle-interval control mode is not in progress, the process proceeds to steps s11 to s13 to execute the acceleration / deceleration control mode before transitioning to the vehicle speed control mode. .

In steps s11 and s12, the acceleration change rate map M-1 is used to set the target acceleration change rate A ₁ to converge with the increase of the elapsed time t after the inter-vehicle distance control mode is stopped. Here, to calculate a target acceleration Aref by the product of the target jerk A ₁ and the headway distance control mode canceled when the vehicle acceleration or deceleration A _F. Further, here, the control speed V ₁ calculated from the vehicle speed V _F when the inter-vehicle distance control mode is stopped and the integrated value of the target acceleration / deceleration Aref is obtained by the following equation.

[0036]

[Equation 1]

Further, the deviation ε between the control speed V ₁ and the actual vehicle speed V
The corrected acceleration / deceleration A ₂ corresponding to the calculated acceleration / deceleration A ₂ is calculated along the corrected acceleration map M-2, and the corrected acceleration / deceleration A ₂ is used to calculate the target acceleration / deceleration Aref.
Is corrected, and the electronic governor 12, which is the acceleration / deceleration means, is driven so as to obtain the corrected target acceleration / deceleration Aref ′. That is, as shown in FIG. 4, the target acceleration / deceleration Aref ′ is always set so that its absolute value is smaller than the absolute value of the acceleration A _F when the inter-vehicle distance mode is stopped, and a convergence characteristic is given. in this case,
In the control range where the target acceleration / deceleration Aref 'is positive (+), the fuel amount signal output to the electronic governor 12 is increased and corrected to negative (-).
The fuel amount signal is reduced and corrected in the control range of. When the target acceleration / deceleration Aref ′ is negative (−) in the control range and the target acceleration / deceleration Aref ′ is excessively large, the exhaust brake device 16, the compression opening type engine brake device 28, and the retarder 9 that are deceleration means are used. It may be driven to increase the effect of engine braking.

In step s13, it is determined whether or not the absolute value of the actual acceleration / deceleration An is equal to or less than the predetermined value ΔVr for a predetermined time α or more. If No, the process returns without changing, and if Yes, the target acceleration / deceleration Aref. 'Is determined to have converged to almost zero side. Here, the process proceeds to step s14 to execute the vehicle speed control mode, shifts from the acceleration / deceleration control mode to the vehicle speed control mode, and the vehicle speed V _F when the inter-vehicle distance control mode is stopped
Is set as the target vehicle speed. Further, in step s15, the vehicle-to-vehicle speed control shift flag is reset, and the process returns to the main routine. As described above, the above-described vehicle travel control device sequentially shifts from the inter-vehicle distance control mode to the vehicle speed control mode for maintaining the vehicle speed at the target vehicle speed in accordance with the vehicle acceleration / deceleration when the inter-vehicle distance control mode is stopped and the elapsed time after the stop. Since the acceleration / deceleration control mode (steps s11 to s13) in which the vehicle travels at the set target acceleration is used, the acceleration of the vehicle can be set so as not to suddenly change, and a smooth transition can be realized.

In particular, when setting the target acceleration / deceleration Aref so that the vehicle speed converges to the target vehicle speed over time (using the acceleration change rate map M-1), the acceleration / deceleration control mode is changed to the vehicle speed control mode. The transition can be done more smoothly. In particular, the target acceleration / deceleration may be determined by the product of the vehicle acceleration / deceleration A _F when the inter-vehicle distance control mode is stopped and the target acceleration change rate A _{1 which} is set so as to converge with an increase in the elapsed time after the stop. In this case, since the acceleration change converges with the elapsed time after the inter-vehicle control mode is stopped, the transition to the vehicle speed control mode becomes smoother,
Excellent feeling.

In particular, in the acceleration / deceleration control mode, the target acceleration / deceleration Aref is set on the basis of the vehicle speed deviation ε between the control speed V ₁ and the actual vehicle speed V calculated from the vehicle speed when the inter-vehicle distance control mode is stopped and the integrated value of the target acceleration / deceleration. You may correct it. In this case, control accuracy can be ensured even when the ability to follow the target acceleration / deceleration is low. In particular, when the absolute value of the target acceleration / deceleration Aref 'and the absolute value of the actual acceleration / deceleration An remain below the predetermined value for a predetermined time α or more, the acceleration / deceleration control mode is switched to the vehicle speed control mode. The shock of time is eliminated and the transition becomes smooth.

In particular, when the preceding vehicle cannot be recognized while traveling in the inter-vehicle distance control mode, the vehicle speed control mode is entered via the acceleration / deceleration control mode, and the vehicle speed V _F when the inter-vehicle distance control mode is stopped is set as the target vehicle speed. You may. In this case, if the preceding vehicle cannot be recognized, the vehicle automatically shifts to the constant speed control mode, so that safe easy drive can be realized, and the change in vehicle speed due to mode switching is small, so that there is no discomfort.

[0042]

As described above, according to the first aspect of the invention, the inter-vehicle distance control mode for maintaining the inter-vehicle distance with the preceding vehicle at the target distance is shifted to the constant speed control mode for maintaining the vehicle speed at the target vehicle speed. At this time, the acceleration / deceleration control mode in which the vehicle travels at a target acceleration that is sequentially set according to the vehicle acceleration / deceleration when the inter-vehicle control mode is stopped and the elapsed time after the stop is used. Therefore, it is possible to set so that the acceleration of the vehicle does not suddenly change when the inter-vehicle control mode is switched to the constant speed control mode, and it is possible to realize a smooth transition from the inter-vehicle auto cruise to the vehicle speed auto cruise.

[Brief description of the drawings]

FIG. 1 is a schematic overall configuration diagram of a vehicle travel control device as an embodiment of the present invention.

FIG. 2 is a functional block diagram of an engine controller used in the vehicle travel control device of FIG.

3 is a schematic configuration diagram of a compression release type engine braking device used by the vehicle travel control device of FIG. 1. FIG.

4A and 4B are diagrams illustrating control characteristics of an engine controller in the vehicle travel control apparatus of FIG. 1, in which FIG. 4A is a diagram showing a change in acceleration and FIG. 4B is a diagram showing a change in vehicle speed.

5 is a flowchart of a vehicle traveling control program executed by a controller in the vehicle traveling control device of FIG.

FIG. 6 is a vehicle speed characteristic diagram in vehicle travel control executed by a controller of a conventional device.

[Explanation of symbols]

1 Engine 11 Engine Controller 17 Solenoid Valve 18 Set Switch 20 Stop Lamp Switch 21 Clutch Switch 23 Vehicle Speed Sensor 24 Inter-Vehicle Sensor 26 Shutter Valve 28 Compression Open Engine Brake Device 39 Solenoid Valve 42 Auxiliary Brake Switch 50 Exhaust Switch 51 Accelerator Switch A1 Target Acceleration change rate A2 Corrected acceleration equivalent to vehicle speed deviation _AF Acceleration / deceleration of vehicle during inter-vehicle distance control mode AC Accelerator switch signal An Actual acceleration B Brake signal B1 1st auxiliary brake drive signal B2 2nd auxiliary brake drive signal CS set signal CR acceleration command signal EB equi shake switch signal M-1 jerk map M-2 corrected acceleration map oN auto cruise oN signal Sc clutch contact signal S _L vehicle distance signal V vehicle speed Issue ε vehicle speed deviation

Claims (6)

[Claims] 1. A vehicle travel control device capable of switching between an inter-vehicle distance control mode for maintaining a vehicle-to-vehicle distance to a preceding vehicle at a target distance and a constant speed control mode for maintaining a vehicle speed at a target vehicle speed. When shifting to the constant speed control mode, it goes through the acceleration / deceleration control mode.In the acceleration / deceleration control mode, the target acceleration / deceleration is sequentially set according to the vehicle acceleration / deceleration when the inter-vehicle distance control mode is stopped and the elapsed time after the stop. A vehicle travel control device configured to drive a vehicle at a target acceleration / deceleration. 2. The vehicle travel control device according to claim 1, wherein the target acceleration / deceleration is set so that the vehicle speed converges to the target vehicle speed over time. 3. The vehicle running control device according to claim 1, wherein the target acceleration / deceleration is set so that the target acceleration / deceleration is set to converge with the vehicle acceleration / deceleration when the inter-vehicle distance control mode is stopped and the elapsed time after the increase. A vehicle travel control device characterized by being determined by the product of 4. The vehicle running control device according to claim 1, wherein, in the acceleration / deceleration control mode, a control speed and an actual vehicle speed calculated from a vehicle speed when the inter-vehicle distance control mode is stopped and an integrated value of the target acceleration / deceleration. A travel control device for a vehicle, wherein the target acceleration / deceleration is corrected on the basis of the deviation. 5. The vehicle running control device according to claim 1, wherein when the absolute value of the target acceleration / deceleration and the absolute value of the actual acceleration / deceleration are below a predetermined value for a predetermined time or more, the acceleration / deceleration control mode is set. To a constant speed control mode described above. 6. The vehicle traveling control device according to claim 1, wherein when the preceding vehicle cannot be recognized while traveling in the inter-vehicle distance control mode, the vehicle moves to the constant speed control mode via the acceleration / deceleration control mode. However, the vehicle traveling control device is characterized in that the vehicle speed when the inter-vehicle distance control mode is stopped is set as the target vehicle speed.