JP4387562B2 - Vehicle constant speed travel control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a driver from having a sense of discomfort or a sense of incongruity due to the occurrence of a downshift on a downhill or the like in a constant speed travel control device for a vehicle provided with an automatic transmission. SOLUTION: When a vehicle is in an accelerating state and a driver seems to have no intention of accelerating in the case the deviation VCCerr between vehicle speed V and target vehicle speed VCCtgt exceeds brake start determination vehicle speed deviation VBKS, a brake actuator is put in action to reduce speed before executing the downshift.

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vehicle constant speed travel control device.
[0002]
[Prior art]
A technology for setting a target vehicle speed according to a driver's instruction input through a set switch, etc., and operating the brake actuator and the throttle actuator so that the detected vehicle speed becomes the target vehicle speed, and driving the vehicle at a constant speed, Well known.
[0003]
Also, when the vehicle is equipped with an automatic transmission, as is well known, a gear ratio (gear) is retrieved from the vehicle speed and throttle opening detected from a preset gear shift scheduling map, and the shift is performed to obtain the retrieved gear ratio. Shift control such as down is performed.
[0004]
[Problems to be solved by the invention]
Therefore, when the above-described constant speed traveling control is performed in a vehicle equipped with an automatic transmission, the automatic transmission control device determines that the target vehicle speed cannot be maintained by engine braking with the current gear ratio on a downhill road or the like. The engine is controlled to shift down to increase the engine braking force and to maintain the target vehicle speed.
[0005]
However, when the gear is shifted down with the throttle fully closed, the acceleration changes abruptly. Therefore, a shift shock may be caused when the gear is downshifted, which may cause driver discomfort. In addition, the driver often feels uncomfortable when downshifting downhill, which does not occur in manual driving.
[0006]
Accordingly, an object of the present invention is to eliminate the above-mentioned inconveniences, and in the constant speed traveling control of a vehicle equipped with an automatic transmission, even when traveling on a downhill road or the like, the vehicle speed is appropriately controlled and the driver is controlled. An object of the present invention is to provide a constant speed travel control device for a vehicle that does not give a sense of discomfort or discomfort to the vehicle.
[0007]
[Means for Solving the Problems]
In order to achieve the above-described object, according to claim 1, in a constant speed traveling control device for a vehicle provided with an automatic transmission, vehicle speed detecting means for detecting a vehicle speed of the vehicle, connected to a brake of the vehicle A target vehicle speed is set according to a driver's instruction input through a brake actuator and a switch for operating the brake, and at least the brake actuator is operated so that the detected vehicle speed becomes the set target vehicle speed. Vehicle speed control means for controlling the vehicle speed of the vehicle, and shift down control means for shifting down the automatic transmission based on at least the detected vehicle speed, the vehicle speed control means has at least the detected vehicle speed. When the target speed exceeds a predetermined value or more, the brake actuator is operated, and the brake Acceleration of the vehicle by the operation of the actuator is Negative value Became When When judging, the downshift control means is configured to permit downshift.
[0008]
When at least the detected vehicle speed exceeds the target speed, the brake actuator is operated and the vehicle acceleration Negative value Became When When judging, the shift down is permitted, in other words, the acceleration is a negative value, that is, the shift down is executed when the deceleration occurs, so that the vehicle speed can be properly controlled and the shift shock is prevented. This can be effectively reduced, and therefore the driver does not feel uncomfortable or uncomfortable.
[0009]
In addition, since the vehicle speed is maintained by the engine braking force after the downshift, the brake is not operated for a long time, and further, the vehicle speed hunting does not occur, so that a good constant speed traveling can be realized.
[0010]
According to a second aspect of the present invention, the vehicle speed control means includes brake oil pressure detection means for detecting oil pressure supplied to the brake, and at least when the detected vehicle speed exceeds the target speed by a predetermined value or more, The brake actuator is operated and the detected brake hydraulic pressure is It is determined that the acceleration of the vehicle has become a negative value Over the specified hydraulic pressure And Ki ,in front The shift-down control means is configured to allow down-shifting.
[0011]
When at least the detected vehicle speed exceeds the target speed by more than a predetermined value, the brake actuator is operated and the detected brake hydraulic pressure It is determined that the vehicle acceleration has become negative Over the specified hydraulic pressure And Ki , Since the configuration is such that the downshift is permitted, the deceleration state of the vehicle can be detected with high accuracy, and the shift shock can be more effectively reduced. In addition, this makes it possible to prevent the brake control from continuing for a long time by shifting down even when the vehicle does not reach a predetermined deceleration when traveling down a steep slope (for example, 10% or more).
[0012]
In the present invention, the vehicle speed control means is based on the target vehicle speed and the detected vehicle speed. The target should be the brake control that controls the operation of the brake actuator Brake target vehicle speed determining means for determining a brake target vehicle speed is provided, and the determined brake Should be targeted in control The brake actuator is configured to operate based on the target vehicle speed.
[0013]
Based on target vehicle speed and detected vehicle speed The target should be the brake control that controls the operation of the brake actuator Since the target vehicle speed is determined and the brake actuator is operated based on the target vehicle speed, sudden braking can be prevented, and the driver does not feel uncomfortable.
[0014]
According to a fourth aspect of the present invention, the brake target vehicle speed determining means is configured to determine the brake based on the detected vehicle speed. Should be targeted in control The initial value of the target vehicle speed is determined.
[0015]
The brake is based on the detected vehicle speed, more specifically, the current vehicle speed at the start of the brake control. Should be targeted in control Since the initial value of the target vehicle speed is determined, the sudden braking can be more effectively prevented.
[0016]
According to a fifth aspect of the present invention, the brake target vehicle speed determining means includes the brake Should be targeted in control Target vehicle speed The above default value From It constituted so that it may decrease in steps.
[0017]
brake Should be targeted in control Target vehicle speed The default value From Since it is configured to decrease stepwise, it is possible to give the driver a smooth braking feeling even after starting the brake control.
[0018]
According to a sixth aspect of the present invention, the brake target vehicle speed determining means is configured to change the brake after the shift down control means is permitted to shift down and shift down. Should be targeted in control The target vehicle speed is increased step by step.
[0019]
Brake down after downshift Should be targeted in control Since the target vehicle speed is increased stepwise, the brake is not operated for a long time after the downshift and the brake can be released smoothly.
[0020]
According to a seventh aspect of the present invention, the vehicle speed control means is configured so that the detected vehicle speed is the brake. Should be targeted in control When the vehicle speed is lower than the target vehicle speed, the operation of the brake actuator is terminated.
[0021]
The detected vehicle speed is the brake Should be targeted in control Since the operation of the brake actuator is terminated when the vehicle speed becomes lower than the target vehicle speed, the brake can be released at an optimal timing after the downshift.
[0022]
According to an eighth aspect of the present invention, the vehicle speed control means includes throttle opening degree detection means for detecting an opening degree of a throttle valve of an internal combustion engine mounted on the vehicle, and the detected throttle valve is in a fully closed position. If not, the operation of the brake actuator is terminated.
[0023]
When the detected throttle valve is not in the fully closed position, the brake actuator operation is terminated. Therefore, the brake can be released at the optimum timing after downshifting, and the driver's acceleration will be given priority. And will not interfere with the driver's operation.
[0024]
According to a ninth aspect of the present invention, the vehicle speed control means includes an accelerator pedal operation detection means for detecting an accelerator pedal operation of the vehicle by a driver, and the operation of the brake actuator is detected when the accelerator pedal operation is detected. Is configured to end the process.
[0025]
As a result, the brake can be released at an optimal timing after the downshift, and the driver's intention to accelerate can be prioritized, and the driver's operation is not interfered with.
[0026]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a constant speed travel control device for a vehicle according to an embodiment of the present invention will be described with reference to the accompanying drawings.
[0027]
FIG. 1 is a schematic diagram showing the constant speed traveling control apparatus for the vehicle as a whole.
[0028]
In FIG. 1, reference numeral 10 denotes a vehicle, and an internal combustion engine (shown as “ENG” in the figure, hereinafter referred to as “engine”) 12 is mounted on the front part thereof. The engine 12 is a spark ignition type multi-cylinder (for example, four cylinder) gasoline engine.
[0029]
The engine 12 includes an intake pipe 14, and the intake air flows in the vicinity of an intake valve (not shown) while the flow rate is adjusted by a throttle valve 16, and is mixed with gasoline fuel injected by an injector (not shown). It flows into each cylinder combustion chamber (not shown). The inflowing air-fuel mixture is ignited and burned to drive a piston (not shown).
[0030]
The engine output (torque) generated by the driving force of the piston is input to an automatic transmission 20 (shown as “AT” in the figure, hereinafter referred to as “AT”). The AT 20 is composed of, for example, a stepped transmission of 4 speeds forward and 1 speed reverse, shifts the input engine output (torque), wheels W through a differential mechanism and a drive shaft (both not shown), That is, the left and right front wheels WFL and WFR are driven, and the left and right rear wheels (driven wheels) WRL and WRR are driven to drive the vehicle 10.
[0031]
A caliper type disc brake B is attached to each wheel W. The disc brake B includes a brake caliper BF or BR, that is, a brake caliper BFL, BFR, BRL, and BRR disposed on each wheel W, and presses the brake disc with these brake pads to brake each wheel W. .
[0032]
The disc brake B disposed on each wheel W is connected to the brake actuator 22. As will be described later, the brake actuator 22 automatically activates the disc brake B to brake the vehicle 10 independently of the operation of the driver.
[0033]
FIG. 2 is a schematic view showing details of the brake actuator 22.
[0034]
As illustrated, the brake actuator 22 includes a master cylinder 24. The master cylinder 24 is connected to a master back 30 connected to a brake pedal 26 disposed on the driver's seat floor of the vehicle 10, and braking according to a stepping force boosted from a reservoir (not shown) therein. The brake oil (oil) adjusted to the pressure is sent to the hydraulic mechanism.
[0035]
As shown in the figure, the hydraulic mechanism includes switching valves 32, 34, and 36, and one chamber 24 a of the master cylinder 24 is connected to an input port of the switching valve 32 through an oil passage 40.
[0036]
During normal brake operation, the solenoids 32 a, 34 a, 36 a of the three switching valves 32, 34, 36 are turned off and are in the positions shown in the figure, and the oil passage 40 is connected to the oil passages 42, 44. Pressure oil is sent to the brake caliper BFL of the left front wheel and the brake caliper BRR of the right rear wheel via the oil passages 40, 42, 44, and brakes the left front wheel WFL and the right rear wheel WRR. Thus, when the driver depresses the brake pedal 26, a braking force (braking force) corresponding to the amount of depression is applied to each wheel W.
[0037]
The other chamber 24b of the master cylinder 24 is sent to the brake calipers BFR and BRL for the right front wheel WFR and the left rear wheel WRL via the oil passage 46 and the oil passage mechanism having the same structure. Is omitted.
[0038]
Although explanation is omitted, by turning on the solenoid 32a of the switching valve 32, turning off only the switching valve for the brake caliper of the wheel to which the braking force should be applied, and turning on the remaining switching valve, Only braking force can be given. In other words, the braking force can be released only from any wheel.
[0039]
On the other hand, when the solenoid 32a of the switching valve 32 is turned on and the solenoids 34a and 36a of the switching valves 34 and 36 are turned off, both the wheels WFL and WRR are braked. When the same processing is performed on the other right front wheel WFR and left rear wheel WRL via a hydraulic mechanism (not shown), all the wheels are braked and the vehicle 10 is automatically braked.
[0040]
Solenoids 32a, 34a, 36a of the switching valves 32, 34, 36 are connected to an ECU (electronic control unit) 54 composed of a microcomputer, and are turned on / off via a drive circuit (not shown).
[0041]
More specifically, these solenoids are duty controlled by the ECU 54, and each brake caliper is pressurized by switching between a state communicating with the master back 30 and the hydraulic pump 48 as a pressure oil source and a state communicating with the reservoir. Alternatively, decompression can be performed, thereby applying an arbitrary braking force to an arbitrary wheel. As described above, the brake actuator 22 is configured as an actuator having an ABS (anti-lock brake system) function.
[0042]
A brake switch 56 is provided at an appropriate position such as in the vicinity of the brake pedal 26. When a brake operation is performed by the driver, an ON signal is output, and oil pressure sensors 58 and 58 are provided in the oil passages 40 and 46, respectively. And a signal corresponding to the brake hydraulic pressure PRbk supplied to the disc brake B (more specifically, the brake caliper BF or BR) is output. The outputs of the brake switch 56 and the hydraulic pressure sensors 58 and 58 are also sent to the ECU 54.
[0043]
The throttle valve 16 is connected to an accelerator pedal 60 disposed on the driver's seat floor of the vehicle 10 via a link mechanism, and opens and closes according to the driver's accelerator pedal operation, and a throttle actuator ("M" in the figure). And 64) and is driven independently of the operation of the accelerator pedal 60.
[0044]
3 and 4 are explanatory views showing details of the throttle actuator 64. FIG.
[0045]
As illustrated, the throttle actuator 64 includes a DC motor (electric motor) 64a, and the DC motor 64a is connected to the output drum 64d via a reduction gear 64b and an electromagnetic clutch 64c. The output drum 64d is connected to an actuator drum 64e fixed to the valve shaft 16a of the throttle valve 16 via an actuator wire 64f.
[0046]
An accelerator drum 64h is fixed to the valve shaft 16a of the throttle valve 16 adjacent to the actuator drum 64e. The accelerator drum 64h is connected to an accelerator pedal 60 (not shown) via an accelerator pedal wire 64i. Further, a throttle arm 64j is attached to the valve shaft 16a of the throttle valve 16.
[0047]
In the above configuration, the rotation of the DC motor 64a is transmitted to the output drum 64d via the reduction gear 64b and the electromagnetic clutch 64c, and the output drum 64d is rotated to wind up the actuator wire 64e and rotate the actuator drum 64e. On the other hand, the driver's accelerator pedal operation winds up the accelerator pedal wire 64i and rotates the accelerator drum 64h.
[0048]
The actuator drum 64e and the accelerator drum 64h operate (rotate) independently, and the one with the larger rotation angle is pushed and released by the throttle arm 64j. The throttle valve 16 is biased to a fully closed position via a return spring (not shown), and returns to the fully closed position when there is no pressing force of the throttle arm 64j.
[0049]
As shown in FIG. 4, in order to ensure the fully closed state of the throttle valve 16, when the throttle actuator 64 and the accelerator pedal 60 are not operated, the throttle arm 64j and the actuator drum 64e (and the accelerator drum 64h) have a throttle. When the valve 16 is in the fully closed position, it is configured to have play (indicated by reference numeral 64p).
[0050]
A throttle opening sensor 66 is provided in the vicinity of the throttle valve 16 and outputs a signal corresponding to the throttle opening, and an accelerator pedal switch 68 is provided in the vicinity of the accelerator pedal 60 so that the driver can operate the accelerator pedal. When not performed, an off signal is output, and when an accelerator pedal operation is performed, an on signal is output. Note that the accelerator pedal switch 68 outputs an ON signal when the accelerator pedal 60 is driven even if it is within the range of play of the accelerator pedal 60. The outputs of these sensors 66 and 68 are also sent to the ECU 54.
[0051]
Further, a shift position switch 70 is disposed at an appropriate position of the AT 20 and outputs a signal corresponding to a range (P, N, D, etc.) selected by the operation of the driver's selector lever (not shown). A vehicle speed sensor 74 is provided at an appropriate position of each wheel W and outputs a signal corresponding to the traveling speed (vehicle speed V) of the vehicle 10. These outputs are also sent to the ECU 54.
[0052]
Further, in the vicinity of the driver's seat, a main switch (indicated as “MAIN” in the figure) 76 for inputting a constant speed traveling command, a set switch (indicated in the figure as “SET”) 78 for inputting an instruction vehicle speed, Resume switch (represented as “RESUME” in the figure) 80 for returning after canceling the constant speed travel command by a brake operation or the like, and a cancel switch for inputting the cancel command for the constant speed travel command (“CANCEL” in the figure) ) 82 is arranged.
[0053]
The outputs of these switch groups are also input to the ECU 54. The ECU 54 determines the input state of these switch groups and displays it through a display 84 (shown as “DISPLAY” in the figure).
[0054]
The ECU 54 sets the target vehicle speed according to the driver's instruction input through the set switch 78, and operates the brake actuator 22 and the throttle actuator 64 so that the detected vehicle speed becomes the target vehicle speed. A gear ratio scheduling (gear) is searched from the detected vehicle speed and throttle opening in a gear shift scheduling map set in advance, and shift control such as downshifting is performed via the shift solenoid 86 so that the searched gear ratio is obtained. I do.
[0055]
Furthermore, the vehicle constant speed traveling control apparatus according to this embodiment includes a following traveling function. That is, a laser radar 90 is provided in the vicinity of the front bumper (not shown) of the vehicle 10 to irradiate the laser beam in the traveling direction and receive the reflected light. The output of the laser radar 90 is sent to a processing ECU (not shown), where the azimuth and distance of an object such as a preceding vehicle located in the traveling direction is detected. The output of the processing ECU is sent to the ECU 54.
[0056]
In addition, a yaw rate sensor 92 is disposed near the center of gravity of the center of the vehicle 10, and a signal corresponding to the yaw rate (angular velocity around the vertical axis) acting on the vehicle 10 is provided, and the inter-vehicle distance setting is set to a time value near the driver's seat. Is set as an inter-vehicle distance setting switch 94.
[0057]
These outputs are also input to the ECU 54, and the ECU 54 performs a follow-up running process in which the vehicle runs following the preceding vehicle while maintaining the distance instructed through the distance setting switch 94 as necessary.
[0058]
The vehicle constant speed traveling control apparatus according to this embodiment relates to constant speed traveling control on a downhill road or the like, and the operation of this control apparatus will be described below with a focus on that point.
[0059]
FIG. 5 is a main flow chart showing the operation. The illustrated program is looped every 100 msec.
[0060]
In the following, it is determined in S10 whether CC is not being controlled, that is, whether constant speed traveling control is not being executed. This is determined by referring to an appropriate flag. When the result in S10 is affirmative, the program proceeds to S12, where the timer (up counter) value tMskBK is reset to zero and the program is terminated.
[0061]
When the result in S10 in the subsequent program loop is negative, the program proceeds to S14, in which it is determined whether the brake is being controlled. Brake control means control via the brake actuator 22, and is usually denied in the first program loop and proceeds to S16 to determine whether initial output is being performed.
[0062]
As described above, when the constant speed running control is started in the throttle actuator 64, the initial process for driving the throttle actuator 64 to the throttle opening degree opened by the accelerator pedal operation is performed. In this step, the initial process is performed. Therefore, it is determined whether or not the DC motor 64a of the throttle actuator 64 is energized.
[0063]
In the first program loop, the determination in S16 is generally denied and the process proceeds to S18 to determine whether VCCtgt has changed. VCCtgt means the target vehicle speed for constant speed running. When the driver changes the indicated vehicle speed via the cancel switch 82 or the like, this determination is affirmed, but usually the determination is negative and the routine proceeds to S20, where it is determined whether or not an accelerator pedal operation has been performed. This is done by determining whether the output of the accelerator pedal switch 68 has changed from off to on.
[0064]
When the result in S20 is affirmative, the process proceeds to S12 in order to prioritize the driver's intention to accelerate. When the result is negative, the process proceeds to S22, in which it is determined whether the timer value tMskBK has exceeded a predetermined value (predetermined time) TOMB. If NO, the process proceeds to S24, and this timer value is incremented. That is, the elapsed time after all the conditions shown in S10 to S20 are satisfied is measured.
[0065]
This is because, for example, when the result is once affirmed in S14 and then denied, the braking force remains for a predetermined time, so that the influence is removed. The same applies to S20 and the like.
[0066]
On the other hand, when the result in S22 is affirmative, the program proceeds to S26, in which it is determined whether VCCerr exceeds a predetermined value VBKS, the acceleration of the vehicle 10 exceeds zero, and the opening of the throttle valve 16 is in the fully closed position. In the above, VCCerr represents a vehicle speed deviation (detected vehicle speed V-target vehicle speed VCCtgt), and VBKS represents a brake start determination vehicle speed deviation. The acceleration is detected by calculating a difference value of the detected vehicle speed V.
[0067]
When the result in S26 is affirmative, the program proceeds to S28, in which the detected vehicle speed V is set to VBKtgt, Go to 30 Perform brake control. VBKtgt means a brake target vehicle speed that should be a target in the brake control.
[0068]
Referring to FIG. 6, this embodiment will be outlined. In this embodiment, the vehicle speed V is controlled in spite of the throttle valve 16 being controlled to the fully closed position, particularly when the road gradient is downhill. When the target vehicle speed VCCtgt is increased to a predetermined value VBKS or higher and the vehicle is accelerating, it is determined that the target vehicle speed VCCtgt cannot be maintained only by the throttle control, and the brake control is started.
[0069]
However, since there is a difference (VBKS) as described above between the detected vehicle speed V and the target vehicle speed VCCtgt at the start of the brake control, if the brake actuator 22 is operated immediately, sudden braking occurs and the driver feels uncomfortable. The current vehicle speed V is set as an initial value of the brake target vehicle speed VBKtgt, and the brake target vehicle speed VBKtgt is decreased stepwise as described later so as not to cause sudden braking.
[0070]
FIG. 7 is a subroutine flowchart of the brake control.
[0071]
In the following description, it is determined whether or not the brake control is being performed in S100. When the result is negative, the subsequent processing is skipped. When the result is affirmative, the process proceeds to S102 to determine whether or not the downshift has been executed.
[0072]
In the first program loop, the determination in S102 is usually denied and the process proceeds to S104, where it is determined whether the brake target vehicle speed VBKtgt exceeds the sum of the target vehicle speed VCCtgt for constant speed running and the brake target vehicle speed lower limit VBKLIM. If YES in step S106, the flow advances to step S106, and the brake target vehicle speed VBKtgt is decreased by subtracting a predetermined value VBKDN (reduced brake target vehicle speed) from the brake target vehicle speed VBKtgt.
[0073]
Next, the routine proceeds to S108, where it is determined whether VBKerr is less than zero, whether the throttle valve 16 is not in the fully closed position, and whether the driver is operating the accelerator pedal.
[0074]
In the above, VBKerr means a vehicle speed deviation at the time of brake control (detected vehicle speed V−brake target vehicle speed VBKtgt). Therefore, the first judgment of S108 means judging whether or not the detected vehicle speed V is less than the brake target vehicle speed VBKtgt.
[0075]
When all three conditions described in S108 are negative, the process proceeds to S110, where the brake output is determined and the brake control is performed.
[0076]
Specifically, the brake control is performed by determining the brake output so that the brake actuator 22 shown in FIG.
[0077]
More specifically, the brake output is determined so that the solenoid 32a of the switching valve 32 is turned on, the solenoids 34a and 36a of the switching valves 34 and 36 are both turned off, and all the wheels W are braked.
[0078]
The brake output is determined by multiplying the deviation by a proportional gain and an integral gain so that the deviation between the detected vehicle speed V and the brake target vehicle speed VBKtgt is reduced.
[0079]
On the other hand, when any one of the three conditions described in S108 is affirmed, the process proceeds to S112 and the brake control is terminated.
[0080]
Further, when the result in S102 is affirmative, the process proceeds to S114, and it is determined whether or not a predetermined time has elapsed since the downshift. When the result is negative, the process proceeds to S108, and when the result is affirmed, the process proceeds to S116 and the brake target vehicle speed VBKtgt is set. The brake target vehicle speed VBKtgt is increased by adding a predetermined value VBKUP (an increase in the brake target vehicle speed).
[0081]
Referring to FIG. 8, as described above, since there is a difference (VBKS) between the detected vehicle speed V at the start of brake control and the target vehicle speed VCCtgt for constant speed travel, if the brake actuator 22 is operated immediately, sudden braking is performed. Therefore, the current vehicle speed V is set to the initial value of the brake target vehicle speed VBKtgt and is gradually reduced to a certain value VCCtgt + VBKLIM.
[0082]
Thereby, the shift shock at the time of downshifting can be reduced more reliably. Further, the vehicle speed deviation at the start of the brake control is not constant, but can be made constant by this configuration, and similarly, the effect of reducing the shift shock at the time of downshifting can be reliably achieved.
[0083]
Further, after a predetermined time has elapsed from the downshift, the brake target vehicle speed VBKtgt is increased stepwise (gradually) by adding the predetermined value VBKUP to the brake target vehicle speed VBKtgt, and the brake control vehicle speed deviation VBKerr becomes less than zero. When (S108), the brake control is terminated (S112).
[0084]
Thereby, the brake is not operated for a long time after the downshift, and the brake can be released smoothly. Further, the driver's intention to accelerate can be prioritized by ending the brake control even when the throttle valve 16 is not in the fully closed position or when the driver is operating the accelerator pedal.
[0085]
As shown in FIG. 9, when the downshift is executed while the brake target vehicle speed VBKtgt is reduced, the shift is performed anyway, so the update of the brake target vehicle speed VBKtgt is stopped.
[0086]
Next, the downshift determination process will be described with reference to FIG. The illustrated program is executed by the ECU 54 at the same interval in parallel with the program shown in the flowchart of FIG.
[0087]
Explained below, in S200, it is determined whether CC control is being executed, that is, whether constant speed running control is being executed and brake control is also being executed, with reference to an appropriate flag. Skip the process.
[0088]
On the other hand, when the result is affirmative in S200, the process proceeds to S202, where it is determined whether or not the detected brake hydraulic pressure PRbk has exceeded a predetermined hydraulic pressure PSFTD (shown in FIG. 6). To do. Thereby, in the shift control performed by the ECU 54, if a downshift condition such as a vehicle speed is satisfied, the downshift is executed even if the downshift condition defined by the gear shift scheduling map is not satisfied.
[0089]
When the result in S202 is negative, the program proceeds to S206, in which it is determined whether the acceleration is less than a predetermined value ALSFTD (for example, zero), more specifically, whether the vehicle 10 is decelerating. If not, the program ends.
[0090]
When the detected brake oil pressure PRbk exceeds the predetermined oil pressure PSFTD, since the acceleration is equivalent to less than the predetermined value ALSFTD (the vehicle 10 is decelerating), when the result in S202 is affirmative, the process does not proceed to S206. Allowed downshift.
[0091]
In this embodiment, as described above, when the detected vehicle speed exceeds the target speed by a predetermined value or more, the brake actuator is operated and the acceleration of the vehicle becomes a predetermined value or less. When When judging, the shift-down is permitted. In other words, the shift-down is executed when the acceleration is a negative value, that is, when deceleration occurs. In other words, the vehicle speed increase is suppressed by the brake control, and the downshift is executed when the deceleration occurs, so that the vehicle can be properly controlled, and the driver feels uncomfortable or uncomfortable. Never give.
[0092]
In addition, since the vehicle speed is maintained by the engine braking force after the downshift, the brake is not operated for a long time, and further, the vehicle speed hunting does not occur, so that a good constant speed traveling can be realized.
[0093]
Furthermore, since the brake target vehicle speed is determined and brake control is performed, sudden braking does not occur and the driver does not feel uncomfortable. In addition, the current vehicle speed V is set to the initial value of the brake target vehicle speed, and the shift shock at the time of downshifting can be more reliably reduced by decreasing stepwise (gradually).
[0094]
Further, after a predetermined time has elapsed from the downshift, the brake target vehicle speed is increased stepwise (gradually), and when the brake control vehicle speed deviation VBKerr is less than zero, the brake control is terminated, thereby downshifting. The brake is not operated later for a long time, and the brake can be released smoothly.
[0095]
Moreover, the driver's intention to accelerate can be given priority by terminating the brake control even when the throttle valve 16 is not in the fully closed position or when the driver is operating the accelerator pedal. There is no interference with driving.
[0096]
In the first and second embodiments, as described above, in the constant speed traveling control device for the vehicle 10 equipped with the automatic transmission (AT20), vehicle speed detecting means (vehicle speed sensor 74, ECU 54) is connected to the brake B of the vehicle and sets the target vehicle speed VCCtgt according to the driver's instruction input through the brake actuator 22 and the switch (set switch 78) for operating the brake, and the detected vehicle speed. Vehicle speed control means (ECU 54) for controlling the vehicle speed of the vehicle by operating at least the brake actuator 22 so that V becomes the set target vehicle speed VCCtgt, and at least the automatic transmission based on the detected vehicle speed V. Downshift control means (ECU 54) for downshifting, and The speed control means operates the brake actuator 22 (S26, S30) when at least the detected vehicle speed V exceeds the target speed VCCtgt by a predetermined value VBKS (brake start determination vehicle speed deviation) or more. The acceleration of the vehicle Negative value ( ALSFTD Less than) Became When When judging, the downshift control means is configured to permit downshift (S206, 204).
[0097]
The vehicle speed control means includes brake oil pressure detection means (hydraulic sensor 58) for detecting the oil pressure PRbk supplied to the brake B, and at least the detected vehicle speed V sets the target speed VCCtgt to a predetermined value VBKS (brake When exceeding the start determination vehicle speed deviation), the brake actuator is operated (S26, S30), and the detected brake hydraulic pressure is It is determined that the acceleration of the vehicle has become a negative value Predetermined hydraulic pressure P It becomes more than SFTD And Ki ,in front The shift-down control means is configured to permit down-shifting (S202, S204).
[0098]
The vehicle speed control means is based on the target vehicle speed VCCtgt and the detected vehicle speed. The target should be the brake control that controls the operation of the brake actuator Brake target vehicle speed determining means (ECU 54, S28, S104, S106, S114, S116) for determining the target vehicle speed VBKtgt is provided, and the determined brake Should be targeted in control The brake actuator 22 is operated based on the target vehicle speed VBKtgt (S108, S110).
[0099]
Further, the brake target vehicle speed determining means is configured to perform the brake based on the detected vehicle speed V. Should be targeted in control The initial value of the target vehicle speed VBKtgt is determined (S28).
[0100]
Further, the brake target vehicle speed determining means includes the brake Should be targeted in control Target vehicle speed VBKtgt The above default value From It is configured so as to decrease stepwise (S104, S106).
[0101]
In addition, the brake target vehicle speed determining means may be configured such that after the shift down control means is permitted to shift down and shift down, the brake target vehicle speed determining means Should be targeted in control The target vehicle speed VBKtgt is increased stepwise (S114, S116).
[0102]
Further, the vehicle speed control means is arranged such that the detected vehicle speed V is the brake Should be targeted in control When the vehicle speed is lower than the target vehicle speed VBKtgt, the operation of the brake actuator 22 is terminated (S108, S112).
[0103]
Further, the vehicle speed control means includes throttle opening detection means (throttle opening sensor 66, ECU 54) for detecting the opening of the throttle valve 16 of the internal combustion engine mounted on the vehicle, and the detected throttle valve When not in the fully closed position, the operation of the brake actuator 22 is terminated (S108, S112).
[0104]
The vehicle speed control means includes an accelerator pedal operation detecting means (accelerator pedal switch 68) for detecting an accelerator pedal operation of the vehicle by a driver, and when the accelerator pedal operation is detected, the operation of the brake actuator is controlled. It is configured to finish (S108, S112).
[0105]
In addition, as shown in parentheses in the processing of S26 in the flowchart of FIG. 5 above, a determination is made as to whether or not the current gear is in the Top gear (maximum gear ratio), and all four conditions including that are included. When is established, the control may proceed to S30 via S28 to perform brake control. That is, when the gear ratio is maximum, downshifting is likely to occur, and thus the above-described disadvantages are likely to occur.
[0106]
In S20 of the flow chart of FIG. 5, the driver's intention to accelerate is determined from the accelerator pedal operation. Instead, the driver's intention to accelerate is determined by determining whether the throttle valve 16 is in the fully closed position. May be.
[0107]
In the flow chart of FIG. 5, the elapsed time after all the conditions shown in S10 to S20 are satisfied is measured. Instead, the elapsed time is individually measured every time the conditions of some steps are satisfied. May be measured.
[0108]
【The invention's effect】
According to claim 1, when at least the detected vehicle speed exceeds the target speed by a predetermined value or more, the brake actuator is operated, and the acceleration of the vehicle is increased. Negative value Became When When judging, the shift down is permitted, in other words, the acceleration is a negative value, that is, the shift down is executed when the deceleration occurs, so that the vehicle speed can be properly controlled and the shift shock is prevented. This can be effectively reduced, and therefore the driver does not feel uncomfortable or uncomfortable.
[0109]
In addition, since the vehicle speed is maintained by the engine braking force after the downshift, the brake is not operated for a long time, and further, the vehicle speed hunting does not occur, so that a good constant speed traveling can be realized.
[0110]
In claim 2, when at least the detected vehicle speed exceeds the target speed by a predetermined value or more, the brake actuator is operated, and the detected brake hydraulic pressure is It is determined that the vehicle acceleration has become negative Over the specified hydraulic pressure And Ki , Since the configuration is such that the downshift is permitted, the deceleration state of the vehicle can be detected with high accuracy, and the shift shock can be more effectively reduced. In addition, this makes it possible to prevent the brake control from continuing for a long time by shifting down even when the vehicle does not reach a predetermined deceleration when traveling down a steep slope (for example, 10% or more).
[0111]
According to claim 3, the brake is applied based on the target vehicle speed and the detected vehicle speed. Should be targeted in control Since the target vehicle speed is determined and the brake actuator is operated based on the target vehicle speed, sudden braking can be prevented, and the driver does not feel uncomfortable.
[0112]
According to the fourth aspect of the present invention, the brake is based on the detected vehicle speed, more specifically, the current vehicle speed at the start of the brake control. Should be targeted in control Since the initial value of the target vehicle speed is determined, the sudden braking can be more effectively prevented.
[0113]
In claim 5, the brake Should be targeted in control Target vehicle speed The default value From Since it is configured to decrease stepwise, it is possible to give the driver a smooth braking feeling even after starting the brake control.
[0114]
In claim 6, after downshifting, the brake Should be targeted in control Since the target vehicle speed is increased stepwise, the brake is not operated for a long time after the downshift and the brake can be released smoothly.
[0115]
In the seventh aspect, the detected vehicle speed is determined by the brake. Should be targeted in control Since the operation of the brake actuator is terminated when the vehicle speed becomes lower than the target vehicle speed, the brake can be released at an optimal timing after the downshift.
[0116]
In claim 8, when the detected throttle valve is not in the fully closed position, the operation of the brake actuator is terminated, so that the brake can be released at an optimal timing after the downshift, and The driver's intention to accelerate can be prioritized and does not interfere with the driver's operation.
[0117]
According to the ninth aspect, similarly, the brake can be released at an optimal timing after the downshift, and the driver's intention to accelerate can be prioritized, and the driver's operation is not interfered with.
[Brief description of the drawings]
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a schematic diagram showing an entire vehicle constant speed traveling control apparatus according to an embodiment of the present invention.
2 is a schematic diagram showing details of a brake actuator in the apparatus of FIG. 1. FIG.
3 is a schematic diagram showing details of a throttle actuator in the apparatus of FIG. 1. FIG.
4 is a schematic diagram showing details of the throttle actuator in the apparatus of FIG. 1 as well. FIG.
FIG. 5 is a main flow chart showing the operation in the apparatus of FIG. 1;
6 is a time chart showing processing of the flow chart of FIG.
FIG. 7 is a subroutine flowchart of brake control in the flowchart of FIG. 5;
FIG. 8 is a time chart showing processing of the flowchart of FIG. 7;
9 is a time chart that similarly shows the processing of the flowchart of FIG. 7;
FIG. 10 is a subroutine flow chart showing a shift down determination process performed in parallel with the flow chart of FIG. 5;
[Explanation of symbols]
10 Vehicle
12 Internal combustion engine
16 Throttle valve
20 Automatic transmission (AT)
22 Brake actuator
54 Electronic Control Unit (ECU)
58 Hydraulic sensor
64 Throttle actuator
66 Throttle opening sensor (throttle opening detecting means)
68 Accelerator pedal switch (Accelerator pedal operation detection means)
74 Vehicle speed sensor (vehicle speed detection means)
76 Main switch
78 Set switch
80 Resume switch
82 Cancel switch
B brake
W wheel

Claims (9)

In a constant speed travel control device for a vehicle equipped with an automatic transmission,
a. Vehicle speed detecting means for detecting the vehicle speed of the vehicle;
b. A brake actuator connected to the brake of the vehicle and operating the brake;
c. Vehicle speed control means for setting a target vehicle speed according to a driver's instruction input through a switch, and operating at least the brake actuator so that the detected vehicle speed becomes the set target vehicle speed to control the vehicle speed of the vehicle ,
And d. Downshift control means for downshifting the automatic transmission based on at least the detected vehicle speed;
The vehicle speed control means operates the brake actuator when at least the detected vehicle speed exceeds the target speed by a predetermined value or more, and the acceleration of the vehicle becomes a negative value by the operation of the brake actuator. When it is determined that the vehicle has traveled, the downshift control means permits the downshift to be performed. The vehicle speed control means includes
e. Brake oil pressure detecting means for detecting the oil pressure supplied to the brake;
And at least when the detected vehicle speed exceeds the target speed by a predetermined value or more, the brake actuator is operated, and the detected hydraulic pressure is determined to be a negative value of the vehicle acceleration. above and became a yellow, cruise control apparatus for a vehicle according to claim 1, wherein said allowing downshift before Symbol downshift control means. The vehicle speed control means includes
f. Brake target vehicle speed determining means for determining a target vehicle speed to be targeted by brake control for controlling the operation of the brake actuator based on the target vehicle speed and the detected vehicle speed;
The vehicle constant speed travel control device according to claim 1, wherein the brake actuator is operated based on a target vehicle speed to be a target in the determined brake control.  4. The constant speed travel control device for a vehicle according to claim 3, wherein the brake target vehicle speed determining means determines an initial value of a target vehicle speed to be targeted by the brake control based on the detected vehicle speed. .  5. The constant speed travel control device for a vehicle according to claim 4, wherein the brake target vehicle speed determining means decreases the target vehicle speed to be targeted in the brake control stepwise from the initial value.  4. The brake target vehicle speed determining means increases the target vehicle speed to be targeted in the brake control stepwise after the shift down control means is permitted to shift down and downshift. The constant speed travel control device for a vehicle according to any one of claims 1 to 5.  The vehicle speed control means terminates the operation of the brake actuator when the detected vehicle speed becomes less than a target vehicle speed to be targeted in the brake control. A constant speed travel control device for a vehicle according to claim 1. The vehicle speed control means includes
g. Throttle opening detection means for detecting the opening of a throttle valve of an internal combustion engine mounted on the vehicle;
The vehicle constant speed travel control device according to any one of claims 1 to 6, wherein when the detected throttle valve is not in a fully closed position, the operation of the brake actuator is terminated. . The vehicle speed control means includes
h. An accelerator pedal operation detecting means for detecting an accelerator pedal operation of the vehicle by a driver;
The vehicle constant speed travel control device according to any one of claims 1 to 6, wherein the operation of the brake actuator is terminated when the accelerator pedal operation is detected.

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