JP2649541B2 - Vehicle constant speed traveling device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a constant-speed traveling device for a vehicle,
More specifically, the present invention relates to a constant-speed traveling device for a vehicle that can respond to a change in traffic flow due to a change in road surface gradient with good responsiveness.

2. Description of the Related Art There is known a constant-speed traveling device for a vehicle in which an opening of a throttle valve of an engine is controlled according to a deviation between an actual vehicle speed and a target vehicle speed so that the vehicle travels at a set vehicle speed. And JP-A-59-192114.).

In a constant-speed traveling device for this type of vehicle, when the deviation between the actual vehicle speed and the target vehicle speed is within a predetermined range, the shift up is performed to improve the fuel efficiency, while the deviation between the actual vehicle speed and the target vehicle speed is improved. Is generally controlled to shift down for acceleration or deceleration (for example, Japanese Patent Publication No. 62-3688).
No. 9 publication. ).

However, as described above, when the deviation between the actual vehicle speed and the target vehicle speed is equal to or more than a certain reference deviation value,
When downshifting is performed, there is a case where the flow is contrary to the flow of the vehicle. That is, when the vehicle is traveling on a downhill, the flow of the entire vehicle is generally faster than when traveling on level ground, and thus the actual vehicle speed is necessarily increased. When the deviation between the vehicle speed and the target vehicle speed is equal to or greater than a certain reference deviation value, downshifting is always performed more than necessary when downshifting is performed, resulting in a shift shock and deteriorating the driving feeling. In addition, since it takes time until the throttle valve opens after executing the downshifting, the vehicle speed further decreases during that time, and it may not be possible to follow the flow of the entire vehicle. In addition, when the vehicle is traveling on an uphill, it is always necessary for the driver to shift down immediately so as to keep up with the traffic flow, so that the deviation from the target vehicle speed is not less than the reference deviation value. There is a case where it is too late to wait until the shift down and shift down, so that the vehicle cannot follow the traffic flow of the entire vehicle.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a constant-speed traveling device for a vehicle that enables constant-speed traveling with good responsiveness to a change in traffic flow caused by a change in road surface gradient.

SUMMARY OF THE INVENTION An object of the present invention is to provide a constant-speed traveling device for a vehicle having a shift-down control unit that detects a deviation between an actual vehicle speed and a target vehicle speed and performs a downshift when the deviation is equal to or greater than a reference deviation value. In the above, the present invention is attained by providing a reference deviation value correcting means for detecting a road surface gradient at the time of traveling at a constant speed and outputting a signal for correcting the reference deviation value to the downshift control means in accordance with the detected road surface gradient. .

According to the present invention, detecting the tread gradient at the time of constant speed traveling,
Since the reference deviation value for executing downshifting is corrected according to the detected road surface gradient, unnecessary downshifting is required when traveling at constant speed on a road surface that does not require immediate downshifting. Is performed, and it is possible to prevent deterioration of the ability to follow a change in traffic flow due to a change in road surface gradient due to downshifting. Conversely, on a road surface having a gradient that requires immediate downshifting When the vehicle is traveling at a constant speed, it is possible to shift down quickly and follow changes in traffic flow due to changes in road surface gradient, and unnecessary downshifts are prevented. It is possible to prevent the driving feeling and the durability of the device from being deteriorated due to the shift shock.

According to a preferred embodiment of the present invention, when the reference deviation value correction means detects that the road surface is downgraded, the reference deviation value correction means outputs a signal for largely correcting the reference deviation value to the downshift control means. Be composed. With this configuration, downshifting is not performed until the deviation between the actual vehicle speed and the target vehicle speed becomes larger during traveling at a constant speed on a downhill, and therefore, the traffic flow is fast because of the downhill. Even so, a temporary decrease in vehicle speed caused by downshifting is prevented, so that it is possible to respond to changes in traffic flow with good response.

According to a further preferred aspect of the present invention, when detecting that the road surface has a downward slope, the reference deviation value correction means outputs a signal for largely correcting the reference deviation value to the downshift control means, When it is detected that the road surface has an upward slope, a signal for correcting the reference deviation value to a small value is output to the downshift control means. With this configuration, it is possible to follow a change in traffic flow with good response when traveling at a constant speed on a downhill, and to quickly shift down when traveling on an uphill at a constant speed. By executing the method, the acceleration performance can be enhanced, so that it is possible to follow the traffic flow with good response.

Examples Hereinafter, based on the accompanying drawings, an embodiment of the present invention will be described.
Add a detailed explanation.

FIG. 1 is an overall schematic diagram of an engine provided with a constant-speed traveling device according to an embodiment of the present invention.

In FIG. 1, a throttle valve 3 for adjusting an intake air amount is provided in an intake passage 2 of an engine 1. The throttle valve 3 is opened and closed by a throttle valve actuator 4 such as a DC motor, and its opening is controlled. Is done. Further, the automatic transmission 5 has a plurality of shift solenoids 6a, 6b, 6c and a lock-up solenoid 7,
A hydraulic circuit (not shown) is switched by a combination of ON and OFF of the shift solenoids 6a, 6b, 6c, and a plurality of hydraulic fastening elements (not shown) are selectively fastened. Operated. A lock-up clutch (not shown) in a torque converter (not shown) is engaged or released by turning on and off the lock-up solenoid 7.

Further, a control unit 8 is provided,
A vehicle speed signal Vn from a vehicle speed sensor 9 for detecting a vehicle speed, an accelerator opening signal α from an accelerator sensor 11 for detecting a depression amount of an accelerator pedal 10 in the form of an accelerator opening, a brake from a brake switch 12 for detecting a brake operation. signal
BR, a throttle valve opening signal TH from a throttle valve opening sensor 13 for detecting the opening of the throttle valve 3;
A gear position signal GP from a gear position sensor 14 for detecting a shift position of the automatic transmission 5 and a mode switch
The shift mode signal M is input to the throttle valve actuator 4, the shift solenoids 6 a, 6 b, 6 c and the lock-up solenoid 7 of the automatic transmission 5, respectively. B and the lock-up control signal C are output. The control unit 8 also includes a main switch 16, a set switch 17,
Operation signals from the resume switch 18 and the coast switch 19 are input, respectively.

FIGS. 2 to 7 and FIGS. 9 to 10 are flow charts showing control by the control unit 8 in the vehicle traveling at a constant speed according to the embodiment of the present invention.

FIG. 2 shows the main routine. In FIG. 2, the control unit 8 initializes the system at the start of operation (step
S1), read detection signals from the various sensors and the like,
Based on these, various information necessary for control is input (S2).

Next, the control unit 8 determines whether or not a condition for executing automatic speed control (ASC) including constant speed traveling control is satisfied (S3). When the main switch 16 is turned on, the shift position is in the D range, and the vehicle speed is equal to or higher than a set value, for example, 40 km / h, it is determined that the automatic speed control condition is satisfied. If the condition is not satisfied, it is determined that the automatic speed control condition is not satisfied, and if the brake is actuated, it is determined that the automatic speed control is released even if the above condition is satisfied. .

As a result, when it is determined that the automatic speed control condition is satisfied, the automatic speed control is executed, and the set switch 17,
In response to the operation of the resume switch 18, the coast switch 19, the operation of the accelerator pedal 10, and the operation of the brake, mode setting control such as a vehicle speed feedback control mode and an acceleration mode is performed (S4), and the target throttle valve opening T corresponding to each mode is performed. Set ₀ (S5). In contrast, when the automatic speed control start condition is determined not satisfied, the process proceeds to the normal throttle valve opening control, based on the accelerator pedal operation amount, sets control the throttle valve opening degree T ₀ (S6 ).

Controller 8 thus outputs a throttle valve control signal A to the throttle valve actuator 4 corresponding to the target throttle valve opening degree T ₀ set in step S5 or S6 (S7), the target opening of the throttle valve 3 It operates at the throttle valve opening T ₀ and the vehicle speed Vn, throttle valve opening TH, accelerator opening α
According to the above, the shift solenoid 6a of the automatic transmission 5,
The shift control signal B and the lock-up control signal C are output to 6b, 6c and the lock-up solenoid 7, and shift control is performed (S8). Further, an acceleration timer Tac for performing a later-described delay process is counted up (S9), and the above-described routine is executed at predetermined time intervals.

FIG. 3 shows a mode setting subroutine for automatic speed control in step S4 of the main routine in FIG. 2 when the automatic speed control condition is satisfied. First, it is determined whether or not the set switch 17 is on (S1
1), if it is operated on, it sets the start flag SF (S12), whether or not the reset condition of the acceleration timer Tac, i.e., determine whether the target vehicle speed V ₀ is not set until then (S13). For example, immediately after the main switch 16 is operated, for example, when the automatic shift control is canceled by the braking operation, by turning on the set switch 17, such as when setting the target vehicle speed V _0, the target vehicle speed V ₀ until it Is not set and the acceleration timer Tac is reset, the acceleration timer Tac is reset to zero (S14). In this state, since the operation of the brake is released, the brake release flag BF is reset to zero (S15), the target vehicle speed is updated one after another by the actual vehicle speed Vn (S16), and the set switch 17 is turned off. The target vehicle speed that is updated when operated to the state
V ₀ is set.

In this way, when the target vehicle speed V ₀ is set, depending on whether the start flag SF has been set to determine whether the automatic speed control execution (S17). That is, when the automatic speed control is being executed, the brake and the accelerator pedal are not operated (S18, S19), and none of the set switch 17, the resume switch 18, and the coast switch 19 are operated, the steps S20 to S20 are performed. If the determination in S24 is NO, the mode shifts to vehicle speed feedback control mode III (constant speed traveling control).

Details the routine is omitted in this vehicle speed feedback control mode III, based on such variation of the deviation and the actual vehicle speed Vn between the actual vehicle speed Vn and the target vehicle speed V _0, and the like PI-PD operation, converges to the target vehicle speed V ₀ Calculate the throttle valve opening Tv required to make the target throttle valve opening
Is set to T _0, feedback control is performed. If the brake is operated during the execution of the vehicle speed feedback control, the brake release flag BF is set (S18, S25),
Stop the vehicle speed feedback control (S24), provided at the time of automatic speed control resumes, the target throttle valve opening degree T _0,
The routine shifts to the normal throttle valve opening control mode I by substituting the steady-state opening Tcon described later. Also, in step S10, even when the automatic speed control start condition is not satisfied, each flag is reset (S27), and then the mode shifts to the normal throttle valve opening control mode I.
Wherein in the determination of step S17 is NO, even if the target vehicle speed V ₀ is not set, similarly shifts to the normal throttle valve opening degree control mode I.

Although the detailed routine of the normal throttle valve opening control mode I is omitted, the accelerator pedal opening α is detected, and the shift mode M (economy, normal, power) and a map corresponding to the accelerator pedal depressed state are selected.
Seeking basic throttle valve opening Tb corresponding to the gear position with respect to the accelerator pedal opening alpha, thereto, an accelerator pedal depression speed correction, the vehicle speed correction, by performing various corrections, such as water temperature correction, the target throttle valve opening degree T ₀ Set.

Further, during execution of the cruise control, the accelerator pedal 10
However, when the opening degree α is operated at a predetermined value αo or more, for example, 5% or more (S19), if the brake is not released (S26), the accelerator acceleration flag AF is set (S2).
9) Shift to accelerator acceleration mode II. Basic The accelerator detailed routine of the acceleration mode II is omitted, which inputs the target throttle opening Tv corresponding to the target vehicle speed V ₀ at the vehicle speed feedback control so far, corresponds to the α accelerator pedal opening degree is depressed obtains the throttle valve opening Tb, sets the sum of the two as the target throttle valve opening degree T _0.

Further, during execution of the vehicle speed feedback control, when the set switch 17 is operated (S20), it executes the set switch operation process P _1. Is the detailed routine omitted this set switch operation process P _1, with respect to on operation of the set switch 17, the acceleration timer Tac is the set value, i.e., determines whether or not exceeds the delay time set, beyond If so, it is determined that the driver is requesting acceleration, or a shift flag for downshifting is set, and the mode shifts to the acceleration mode. On the other hand, if the acceleration timer Tac has not exceeded the set value, the shift flag is reset to inhibit downshifting, and the process shifts to the above-described vehicle speed feedback control mode III.

Although the details of the acceleration mode associated with the acceleration operation of the set switch 17 are not shown, the actual vehicle speed Vn is input, and initially the difference between the current target valve opening Tv and the flat ground steady running throttle valve opening Tcon with respect to the actual vehicle speed Vn. From the corresponding load compensation opening Tdis such as a hill running state, and the acceleration of the vehicle at a constant acceleration by the load compensation opening Tdis and the throttle valve opening Tres for acceleration at a constant acceleration on level ground. The target throttle valve opening To
Set.

Also, it performed at the vehicle speed feedback control, when coast switch 19 is turned on for the reduction, the YES determination at step S21, the coast switch operation process P _2. This of more coast switch operation process P ₂ is not shown, with respect to on operation of the coast switch 19,
Update the target vehicle speed V _0, to migrate to the coast mode. Although details of the coast mode are not shown, the target throttle valve opening To
Is set to zero, the throttle valve 3 is fully closed to decelerate, the actual vehicle speed Vn when the coast switch 19 is off is set to the target vehicle speed Vo, and the process returns to the vehicle speed feedback control.

Furthermore, in the vehicle speed feedback control, in a state where the automatic speed control is released with the brake operation,
When the resume switch 18 is turned on to reset the target vehicle speed Vo to the original set value, YES in step S22
Determined by, the process proceeds to resume switch operation P _3, while accelerating to the original target vehicle speed Vo, in the resume flag RF which is set to hold the resume switch operation P _3, holds a YES determination in step S23, to migrate to resume switch operating P _3. This of more resume switch operation P ₃ is not shown, with respect to on operation of the resume switch 18, thereby setting the resume flag RF, or the deviation between the target vehicle speed Vo and the actual vehicle speed Vn is within the predetermined value, i.e., Then, it is determined whether or not the vehicle is in the convergence state. If it is determined that the vehicle is in the convergence state, the resume flag RF is reset, and the process shifts to the vehicle speed feedback control mode III. On the other hand, when it is determined that the vehicle is not in the convergence state, the mode is shifted to the acceleration mode by the set switch 17 described above, and until the target vehicle speed Vo is reached.
The target throttle valve opening To is set so as to accelerate at a constant acceleration.

FIG. 4 shows a shift control subroutine in S8 of the main routine shown in FIG. First, it is determined whether or not automatic speed control is being performed (S30), and if it is determined that automatic speed control is being performed, the determinations in steps S31 to S36 are NO, that is, the accelerator pedal operation is not performed,
If the set switch 17, coast switch 19, and resume switch 18 are not turned on, the brake is not being released, and the accelerator is not accelerating, step S37 is executed.
The vehicle speed feedback shift control is performed, and as will be described in detail later, three times depending on the actual vehicle speed Vn and the throttle valve opening TH.
Upshift or downshift between the fourth speed and the fourth speed is performed. After the accelerator acceleration (S36), when the deviation between the target vehicle speed Vo and the actual vehicle speed Vn falls within a predetermined value, for example, within 2 km / h, the accelerator acceleration flag AF is reset (S38, S39), Perform vehicle speed feedback shift control (S3
7).

On the other hand, when the accelerator pedal is depressed during execution of the automatic speed control (S31), the normal shift control is performed in step S40. In this normal shift control, shift control is performed based on a shift pattern according to the actual vehicle speed Vn and the accelerator opening α. Also, during the execution of the automatic speed control, if the brake is released (S35), if the vehicle speed does not converge after the accelerator is accelerated (S38), or if the automatic shift control is not being executed (S30), the same step is performed. Proceeding to S40, normal shift control is performed.

When the set switch 17 is turned on for acceleration in the state where the vehicle speed feedback shift control is being executed, a determination of YES is made in step S32, the process proceeds to step S41, and the set shift control is performed. The shift stage is shifted down from the fourth speed to the third speed, and the switch flag WF is set to 1.

On the other hand, when the coast switch 19 is turned on for deceleration, a determination of YES is made in step S33,
Proceeding to step S42, coast shift control is performed, and the shift speed is shifted down from fourth speed to third speed, and the switch flag WF
Is set to 3.

Further, when the resume switch 18 is turned on to reset the target vehicle speed after the brake is released,
That is, during the resume operation, a determination of YES is made in step S34, the process proceeds to step S43, and the resume shift control is performed. In the resume shift control, the shift speed is shifted down to the third speed, the vehicle is accelerated, and the switch flag WF is set to 2.

FIG. 5 shows a detailed routine of the vehicle speed feedback shift control in step S37. First, it is determined whether or not the switch flag WF is reset (S5).
0). The switch flag WF is set in each of the set shift control, coast shift control, and resume shift control in steps S41 to S43, and when those shift controls are completed and the process first shifts to vehicle speed feedback shift control, step S51 is executed. And resets the switch flag WF, and shifts up from the third gear down to the fourth gear for acceleration or deceleration in the above-described set shift control, coast shift control, and resume shift control to the fourth gear ( S52).

In step S53, the throttle valve average opening THR is input.
Is a value obtained by adding the detected throttle valve opening THn over a predetermined number of times in the past and averaging it.In the vehicle speed feedback shift control, this average value THR is used, and a hunting phenomenon occurs in the throttle valve opening itself. In this case, the shift hunting is prevented from occurring in response to the hunting of the throttle valve opening.

Subsequently, it is determined from the gear position signal GP whether or not the current speed is the third speed (S54).
First, it is determined whether or not there is a torque margin based on whether or not the throttle valve opening THR exceeds a predetermined value, for example, 80% (S55).
If the throttle valve opening is large and there is no torque margin, downshifting is performed in step S56.

On the other hand, if there is still enough torque, step S5
At 7, it is determined whether the actual vehicle speed Vn is higher than the target vehicle speed Vo (S57). As a result, the actual vehicle speed Vn becomes equal to the target vehicle speed Vo.
When it is determined that the value is larger than the reference value, the control unit 8 determines that the vehicle is traveling on a downhill, and the control unit 8 experimentally determines and stores the reference deviation value Vf when traveling on a flat surface in advance as the reference deviation value. The larger reference deviation value Vd for down traveling is read, and it is determined whether the deviation between the target vehicle speed Vo and the actual vehicle speed Vn is larger than the reference deviation value Vd for down traveling (S58). As the reference deviation value Vd for downhill traveling, for example, a value such as 8 km / h is selected. If the result of determination is YES, that is, if the deviation between the target vehicle speed Vo and the actual vehicle speed Vn is greater than Vd, downshifting is performed (S59). On the other hand, when NO, that is, the target vehicle speed V
When the deviation between o and the actual vehicle speed Vn is not greater than Vu, it is further determined whether the actual vehicle speed change rate ΔVn is larger than the set vehicle speed change rate ΔVs that has been experimentally determined in advance and stored in the control unit 8. Is determined (S60). As a result, when YES, that is, when it is determined that the change rate ΔVn of the actual vehicle speed is larger than the set vehicle speed change rate ΔVs, the vehicle speed is converging, but the actual vehicle speed Vn is rapidly increasing due to the downward slope. Therefore, downshifting is executed (S59), and control is performed so as to apply the engine brake. On the other hand, NO, that is, the change rate ΔVn of the actual vehicle speed
Is not greater than the set vehicle speed change rate ΔVs, the fourth speed is maintained because the vehicle speed is converging and the actual vehicle speed Vn has not increased rapidly (S61).

On the other hand, when it is determined that the actual vehicle speed Vn is not higher than the target vehicle speed Vo, it is determined that the vehicle is traveling on an uphill, and the control unit 8 determines and stores the reference deviation value experimentally in advance. In addition, a reference deviation value Vu for ascending traveling which is smaller than the reference deviation value Vf when traveling on level ground is read, and whether a deviation between the target vehicle speed Vo and the actual vehicle speed Vn is greater than the reference deviation value Vu for ascending traveling is determined. Is determined (S62).
As the reference deviation value Vu for uphill traveling, for example, 5 km / h
Is selected. If the result of determination is YES, that is, if the deviation between the target vehicle speed Vo and the actual vehicle speed Vn is greater than Vu, downshifting is performed (S63). On the other hand, NO
In other words, when the deviation between the target vehicle speed Vo and the actual vehicle speed Vn is not greater than Vu, the change rate ΔVn of the actual vehicle speed is further experimentally determined in advance, and the setting stored in the control unit 8 is used. It is determined whether or not the vehicle speed change rate ΔVs is greater than (S64). As a result, when YES, that is, when it is determined that the change rate ΔVn of the actual vehicle speed is greater than the set vehicle speed change rate ΔVs, the vehicle speed is converging, but the actual vehicle speed Vn is rapidly decreasing due to the upward gradient. Therefore, downshifting is executed (S63), and control is performed so as to apply the engine brake. On the other hand, when NO, that is, when it is determined that the actual vehicle speed change rate ΔVn is not larger than the set vehicle speed change rate ΔVs, the vehicle speed is converged,
In addition, since the actual vehicle speed Vn has not sharply decreased, the fourth speed is maintained (S61).

Next, if the current gear is the third speed and the determination in step S54 is YES, the process proceeds to the shift-up control in steps S65 to S72. First, the throttle valve opening is set to a predetermined value, for example, 80%. It is determined whether or not there is a torque margin based on whether or not it is exceeded (S65). If it is determined that the throttle valve opening is large and there is no torque margin, shifting up to the 4th speed decreases the vehicle speed. The shift speed is maintained at the third speed (S66). On the other hand, if it is determined that the throttle valve opening is small and there is still a torque margin, in step S67, the deviation between the target vehicle speed Vo and the actual vehicle speed Vn is reduced to a predetermined value, for example, a vehicle speed convergence within ± 3 km / h. It is determined whether or not the vehicle is in the vehicle speed state. If it is determined that the vehicle speed is converging, the gear is shifted up to the fourth speed in terms of fuel efficiency (S68). It is determined whether Vn is smaller than a predetermined value, for example, 3 to 5 km / h (S69).

If the actual vehicle speed Vn is low and the vehicle speed is decreasing due to an uphill or the like, in step S70, a larger torque is determined depending on whether the throttle valve opening THR is smaller than a predetermined value, for example, 60%. When it is determined whether or not there is a margin, and when it is determined that the throttle valve opening THR is small and the torque margin is sufficient, the fourth speed is shifted up (S71). On the other hand, when the throttle valve opening THR is small, the torque is reduced. When it is determined that there is not enough room,
Maintain the speed (S72).

FIG. 6 shows another control example in the present embodiment, and shows a modification of the portion indicated by X in the flowchart of FIG.

In FIG. 6, the control unit 8
It is determined whether the traveling zone is an uphill traveling zone, a flatland traveling zone, or a downhill traveling zone (S100). Fig. 7 shows the climbing zone
8 is a flowchart showing a subroutine for determining a driving zone for determining whether the driving zone is a flatland traveling zone or a downhill traveling zone. The control unit 8 is experimentally determined and stored in advance as shown in FIG. The driving zone is determined based on the driving zone determination map. 8th
In the figure, a curve F indicates the relationship between the vehicle speed and the throttle valve opening during steady running on flat ground,
If the throttle valve opening for a certain vehicle speed is larger than during steady-state running on level ground, that is, if the driving state is above this curve F, a larger load is required to obtain the vehicle speed. Therefore, it can be determined that the vehicle is in the uphill traveling state (driving zone II). On the other hand, when the throttle valve opening for a certain vehicle speed is smaller than during steady traveling on flat ground, that is, the driving state is When the vehicle is below the curve F, it indicates that a smaller load is sufficient to obtain the vehicle speed. Therefore, it can be determined that the vehicle is in a downhill traveling state (driving zone 0). By determining whether the driving state is above or below this curve F, it is possible to determine whether the vehicle is traveling uphill or traveling flat (driving zone I). It is theoretically possible to determine slope traveling state. However, when the driving zone is determined only by whether the driving state is above or below the curve F, a determination error is likely to occur.
In the present embodiment, a correction is made so that the driving zone is determined to be in a flatland running state within a certain range above and below a curve F indicating the relationship between the vehicle speed and the throttle valve opening during steady running on the flatland. The value β is determined to prevent hunting of the shift control due to a determination error. Here, the larger the value of β is set, the smaller the slope of the tread becomes, the lower the decision of the driving zone II or the driving zone 0 will be. If the driving zone is determined, the significance of performing the downshift control is small. Conversely, the smaller the setting, the easier it is to determine the operation zone II or the operation zone 0, and the significance of performing the downshift control by determining the operation zone increases. Since the mistakes increase, the value of β should be experimentally determined in consideration of such points.

First, the control unit 8 reads the throttle valve opening Tf and the correction value β in the steady-state operation on the flat ground from the driving zone determination map based on the vehicle speed signal Vn from the vehicle speed sensor 9 (S121). Next, it is determined whether or not the throttle valve opening signal TH from the throttle valve opening sensor 13 satisfies Tf + β> TH (S122).

As a result, when the determination is NO, it is determined that the driving zone is in the uphill traveling zone, that is, the driving zone II (S123). On the other hand, when the determination is YES, the driving zone is not the uphill traveling zone, that is, it is determined to be either the downhill traveling zone or the flatland traveling zone. It is determined whether or not it is (S124).

As a result, if YES, it is determined that the driving zone is in the downhill traveling zone, that is, driving zone 0 (S12).
5) On the other hand, if NO, the driving zone is determined to be a flatland traveling zone, that is, driving zone I (S126).

Thus, after the driving zone is determined, the driving zone 0
It is determined whether or not (S101). As a result, when the result is YES, it can be determined that the vehicle is in the downhill traveling zone. Therefore, the control unit 8 sets the reference deviation value Vd for downhill traveling that is larger than the reference deviation value Vf when traveling on level ground as the reference deviation value.
Is read, and it is determined whether or not the deviation between the target vehicle speed Vo and the actual vehicle speed Vn is larger than the reference deviation value Vd for down traveling (S102). As the reference deviation value Vd for downhill traveling, for example, a value such as 8 km / h is selected. If the result of determination is YES, that is, if the deviation between the target vehicle speed Vo and the actual vehicle speed Vn is greater than Vd, downshifting is performed (S103).
On the other hand, when NO, that is, when the deviation between the target vehicle speed Vo and the actual vehicle speed Vn is not larger than Vu, it is further determined whether or not the actual vehicle speed change rate ΔVn is larger than the set vehicle speed change rate ΔVs. Perform (S104). As a result, when YES, that is, when it is determined that the change rate ΔVn of the actual vehicle speed is larger than the set vehicle speed change rate ΔVs, the vehicle speed is converging, but the actual vehicle speed Vn is rapidly increasing due to the downward slope. Therefore, downshifting is executed (S103), and control is performed so as to apply the engine brake. On the other hand, when NO is determined, that is, when it is determined that the actual vehicle speed change rate ΔVn is not larger than the set vehicle speed change rate ΔVs, the vehicle speed is converging and the actual vehicle speed Vn does not increase rapidly. Then, the fourth speed is maintained (S104).

On the other hand, when it is determined that the operation state is not in the operation zone 0, it is further determined whether or not the operation state is in the operation zone II (S105). As a result, when the result is YES, it can be determined that the vehicle is in the uphill traveling zone. Therefore, the control unit 8 reads out the reference deviation value Vu for ascending traveling smaller than the reference deviation value Vf during traveling on level ground as the reference deviation value. Then, it is determined whether or not the difference between the target vehicle speed Vo and the actual vehicle speed Vn is larger than the reference deviation value Vu for the upward traveling (S106).
As the reference deviation value Vu for traveling uphill, for example, 3 km / h
Is selected. If the result of determination is YES, that is, if the deviation between target vehicle speed Vo and actual vehicle speed Vn is greater than Vu, downshifting is performed (S109). On the other hand, NO
In other words, when the deviation between the target vehicle speed Vo and the actual vehicle speed Vn is not greater than Vu, the change rate ΔVn of the actual vehicle speed is further experimentally determined in advance, and the setting stored in the control unit 8 is used. It is determined whether or not the vehicle speed change rate ΔVs is greater than (S107). As a result, YES,
When it is determined that the actual vehicle speed change rate ΔVn is greater than the set vehicle speed change rate ΔVs, the vehicle speed is converging, but it means that the actual vehicle speed Vn is rapidly decreasing due to the upward slope, and thus shifting is performed. Down is executed (S108), and control is performed so as to apply the engine brake. In contrast, NO,
That is, when it is determined that the change rate ΔVn of the actual vehicle speed is not larger than the set vehicle speed change rate ΔVs, the vehicle speed is converging, and the actual vehicle speed Vn does not decrease rapidly.
Maintain 4th gear without downshifting (S1
09).

On the other hand, when it is determined that the driving state is not in the driving zone II (S105), the control unit 8
As a reference deviation value, a reference deviation value Vf during traveling on level ground is read, and it is determined whether a deviation between the target vehicle speed Vo and the actual vehicle speed Vn is greater than the reference deviation value Vf (S110). For example, a value such as 5 km / h is selected as the reference deviation value Vf for traveling on flat ground. If the result of determination is YES, that is,
If the deviation between the target vehicle speed Vo and the actual vehicle speed Vn is larger than Vf, a downshift is performed (S111). On the other hand, when NO, that is, the deviation between the target vehicle speed Vo and the actual vehicle speed Vn is Vf
If it is not larger, the vehicle speed is converging, so that the fourth speed is maintained (S112).

In the present embodiment, when the vehicle is traveling at a constant speed on a downhill, Vd larger than the reference deviation value Vf for traveling on flat ground is adopted as the reference deviation value for determining whether or not to execute the downshift. If the vehicle is traveling uphill at a constant speed, Vu smaller than the reference deviation value Vf for traveling on level ground is adopted as the reference deviation value for determining whether or not to perform downshifting. During traveling, downshifting is difficult to execute, and a temporary decrease in vehicle speed due to downshifting can be prevented. Therefore, it is possible to quickly follow a change in traffic flow caused by a change in road surface gradient. Also, when traveling uphill, downshifting is quickly performed, and it is possible to quickly follow a change in traffic flow caused by a change in road surface gradient without causing a decrease in vehicle speed. . Further, since unnecessary downshifting is prevented, it is also possible to prevent the driving feeling and the durability of the device from being deteriorated due to the shift shock.

Further, in the present embodiment, the shift-up control in the case where the constant speed traveling control is executed is based on the torque margin based on the throttle valve average opening THR and the deviation between the target vehicle speed Vo and the actual vehicle speed Vn. If the average throttle valve opening THR is greater than the predetermined 80%, it is determined that there is no torque margin, and even if the vehicle speed has converged, no shift up is performed, and the average throttle valve opening THR is not performed. Is given 8
If the actual vehicle speed Vn does not converge to the target vehicle speed Vo even if it is 0% or less, and the throttle valve average opening degree THR is a predetermined 60% or more, it is determined that there is not enough torque margin, and the upshift is performed. It is controlled not to execute. When the actual vehicle speed Vn substantially coincides with the target vehicle speed Vo, and the throttle valve average opening THR has a torque margin of 80% or less, and the actual vehicle speed Vn is slightly small near the target vehicle speed Vo. At the time of sub-vehicle speed convergence, control is performed so that upshifting is executed only when there is a sufficient torque margin of the throttle valve average opening degree THR of 60% or less of a predetermined value. Therefore, even when traveling on a slope, it is possible to perform accurate constant speed traveling control with a small change in vehicle speed with sufficient torque margin, and to prevent the occurrence of shift hunting in which shifting is repeated in a short time. Is done.

The present invention is not limited to the embodiments described above, and various modifications are possible within the scope of the invention described in the claims, which are also included in the scope of the present invention. Needless to say.

For example, in the above-described embodiment, the determination as to whether the driving state is an uphill traveling state, a flatland traveling state, or a downhill traveling state is performed using the driving zone determination map during the steady driving state on the flatland. Is performed by comparing a curve indicating the relationship between the vehicle speed and the throttle valve opening with the driving state at that time.However, the means for detecting or determining the slope of the tread is not particularly limited. Alternatively, the slope of the tread can be detected or determined by a slope sensor that directly detects the slope of the vehicle.

Further, in the above-described embodiment, values such as 80%, 60%, and 20% are used as the set opening of the throttle valve average opening THR for determining the torque allowance. It can be set appropriately according to the output characteristics and the like, and it is needless to say that the present invention is not limited to these.

Effects of the Invention According to the present invention, it is possible to achieve a constant speed running that responds responsively to a change in traffic flow due to a change in road surface gradient, and to prevent a shift shock and a vehicle capable of preventing deterioration of durability of the device. It becomes possible to obtain a high-speed traveling device.

[Brief description of the drawings]

FIG. 1 is an overall schematic diagram of an engine provided with a constant-speed traveling device according to an embodiment of the present invention. 2 to 7 show:
4 is a flowchart illustrating control by a control unit 8 in the constant-speed traveling device for a vehicle according to the embodiment of the present invention. FIG. 8 is an operation zone determination map used in the embodiment of the present invention. 1 ... engine, 2 ... intake passage, 3 ... throttle valve, 4 ... throttle valve actuator, 5 ... automatic transmission, 6a, 6b, 6c ... shift solenoid, 7 ... lock-up solenoid, 8 Control unit, 9 Vehicle speed sensor, 10 Accelerator pedal, 11 Accelerator sensor, 12 Brake switch, 13 Throttle valve opening sensor, 14 Gear position sensor, 15 Mode Switch, 16: Main switch, 17: Set switch, 18: Resume switch, 19: Coast switch

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshihiro Matsuoka 3-1 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Inside Mazda Corporation (56) References JP-A-64-109131 (JP, A) JP-A-64 JP-A-109132 (JP, A) JP-A-62-255250 (JP, A) JP-A-62-168724 (JP, A) JP-A-62-168725 (JP, A) JP-A-62-241734 (JP, A) )

Claims (2)

(57) [Claims] 1. A constant-speed traveling device for a vehicle having a shift-down control means for performing a downshift when a deviation between an actual vehicle speed and a target vehicle speed is detected and the deviation is equal to or greater than a reference deviation value. And a reference deviation correction means for outputting a signal for correcting the reference deviation to the downshift control means in accordance with the detected road gradient. Traveling device. 2. The system according to claim 1, wherein said reference deviation value correcting means outputs a signal for largely correcting said reference deviation value to said downshift control means when detecting that the road surface gradient is down. 2. The constant speed traveling device for a vehicle according to claim 1.