JP4259293B2 - Vehicle travel control device - Google Patents

Description

  The present invention relates to a vehicular travel control device that controls a transmission gear ratio based on a throttle opening and a travel speed.

For example, for the purpose of suppressing shift hunting of an automatic transmission during climbing and descending, when the travel speed difference between the actual travel speed and the target travel speed is greater than or equal to a first predetermined value, the gear ratio is It is changed so as to increase, that is, the downshift is performed, and the running resistance of the vehicle is estimated. It has been proposed to change the gear ratio so that it becomes smaller when it is smaller than the estimated value of running resistance before downshift by a predetermined value or more, that is, to control the gear ratio so as to upshift (for example, Patent Document 1).
JP-A-10-59014

Incidentally, for example, some inter-vehicle distance control devices that automatically adjust the inter-vehicle distance between the preceding vehicle and the host vehicle control the traveling speed of the host vehicle by adjusting the throttle opening. On the other hand, a general gear ratio control device for an automatic transmission controls a gear ratio using a throttle opening and, for example, a traveling speed. Therefore, for example, when a device that adjusts the throttle opening, such as the inter-vehicle distance control device, adjusts the throttle opening, the gear ratio control device finely controls the gear ratio according to the adjusted throttle opening. As a result, there is a problem that the gear ratio control is hunted.
In order to solve the above-described problems, an object of the present invention is to provide a vehicular travel control apparatus that can suppress and prevent hunting in gear ratio control.

In order to solve the above problems, a vehicle travel control apparatus according to the present invention includes a target travel speed setting unit that sets a target travel speed of the host vehicle, a travel speed detection unit that detects the travel speed of the host vehicle, Target drive torque calculating means for calculating a target drive torque so that the travel speed becomes the target travel speed, throttle opening adjusting means for adjusting the throttle opening according to the target drive torque, and the throttle opening In a vehicle travel control device comprising a gear ratio control means for controlling a gear ratio of a transmission based on the travel speed, a gear ratio detection means for detecting a current gear ratio of the transmission; From the first throttle opening degree estimation means for estimating the first throttle opening degree necessary for obtaining the target drive torque at the gear ratio, the first throttle opening degree and the traveling speed, a first A first speed ratio estimating means for estimating a speed ratio; a second throttle opening degree estimating means for estimating a second throttle opening degree necessary for obtaining the target drive torque at the first speed ratio; Second speed ratio estimating means for estimating a second speed ratio from the throttle opening of 2 and the travel speed, the current speed ratio is different from the first speed ratio, and the current speed ratio Throttle opening restriction means for restricting the throttle opening so that the current transmission ratio is not changed to the first transmission ratio when the second transmission ratio is the same. It is a feature.
Note that limiting the throttle opening so that the current gear ratio is not changed to the first gear ratio means, for example, that the gear ratio has been changed by downshifting or upshifting as a result of adjusting the throttle opening. In this case, the actual throttle opening is limited so as to maintain the current gear ratio so that the gear ratio is not changed again in the reverse direction.

  Thus, according to the vehicle travel control apparatus of the present invention, if the current gear ratio is different from the first gear ratio, and the current gear ratio and the second gear ratio are the same, The throttle opening is limited so that the gear ratio is not changed from the gear ratio to the first gear ratio, so that once the gear ratio is changed, it is prevented from being changed again in the opposite direction to suppress transmission hunting. can do.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a system configuration diagram showing an embodiment of a vehicle with a preceding vehicle follow-up travel control device to which the vehicle travel control device of the present invention is applied. This vehicle is a rear wheel drive vehicle in which the rear wheels 1RL and 1RR are driving wheels and the front wheels 1FL and 1FR are driven wheels, and the driving torque of the engine 2 is transmitted to the rear wheels 1RL and 1RR via the automatic transmission 3. Is done.

  The engine control device 11 can control the rotation state, torque, output, and the like of the engine 2. Specifically, the engine rotation state, torque, output, etc. can be controlled by adjusting the throttle valve opening, idle valve opening, ignition timing, fuel injection amount, fuel injection timing, and the like. In this embodiment, a so-called electronically controlled throttle valve is used in which the throttle valve 5 is not mechanically connected to the accelerator pedal, but the opening degree of the throttle valve 5 is adjusted by the motor 6. That is, by controlling the rotation angle of the motor 6, the opening degree of the throttle valve 5 can be controlled, and the throttle opening degree, that is, the engine rotation state, torque, output, etc. can be controlled separately from the depression amount of the accelerator pedal. I did it.

  The automatic transmission 3 is a stepped automatic transmission having five forward speeds and one reverse speed, and can be controlled by a transmission control device 12. Specifically, by adjusting the working fluid pressure supplied to the clutch and brake in the automatic transmission 3, the selected gear ratio (gear position) is changed to obtain a desired gear ratio (reduction ratio). Can be. In this transmission control device 12, for example, according to the transmission ratio control map shown in FIG. 2, the transmission ratio control is performed based on the opening degree of the throttle valve 5 and the traveling speed. In the figure, a curve with numerals and arrows is a shift line, and the gear ratio is changed when the coordinate point of the throttle opening and the traveling speed exceeds each shift line. That is, for example, when the coordinate point consisting of the throttle opening and the traveling speed shifts from the left area of the 3 → 4 shift line to the right area, the gear ratio corresponding to the third gear is changed to the gear ratio corresponding to the fourth gear. In other words, when the so-called upshift and the coordinate point consisting of the throttle opening and the traveling speed shifts from the right region to the left region of the 4 → 3 shift line, the gear ratio corresponding to 4 gears is changed to 3 gears. The ratio is changed, so-called downshift. Here, as is apparent from the figure, the upshift shift line and the downshift shift line are deviated and so-called hysteresis is provided to prevent frequent change of the gear ratio. It should be noted that the current gear ratio is maintained when the coordinate point formed by the throttle opening and the traveling speed is on the shift line.

  The wheels 1FL to 1RR are provided with wheel cylinders 4FL to 4RR constituting so-called disc brakes. The wheel cylinders 4FL to 4RR apply a braking force to the wheels 1FL to 1RR by the supplied brake fluid pressure. The braking force applied to each of the wheels 1FL to 1RR can be controlled by the braking fluid pressure control device 13. Specifically, for example, each wheel cylinder 4FL˜ is increased by increasing the brake fluid pressure as in the driving force control device (TCS) or decreasing the brake fluid pressure as in the anti-skid control device (ABS). The braking fluid pressure to 4RR can be adjusted and the braking force to each wheel 1FL-1RR can be controlled. The braking fluid pressure regulated in the braking fluid pressure control device 13 is supplied from a master cylinder 22 that is boosted by depressing the brake pedal 21.

Each of these control devices controls the traveling state of the vehicle, and as a result, the traveling state can be controlled by adjusting the acceleration / deceleration of the host vehicle, the front-rear direction speed, that is, the traveling speed.
Of course, these control devices can operate alone, but the overall functions are governed by the automatic travel control device 10 including travel speed control and preceding vehicle following travel control. The automatic travel control device 10 performs various arithmetic processes to control the travel state of the vehicle, thereby performing travel speed control, preceding vehicle following travel control, and the like.

  In addition, the vehicle is equipped with, for example, a CCD camera, a laser radar, or the like, and is in a state in front of the host vehicle, for example, a front lane state, the presence or absence of a preceding vehicle, a distance to the preceding vehicle, or a front state that detects the shape of the preceding vehicle. Detection device 16, wheel speed sensor 17 (running speed detection means) that detects the rotational speed of each wheel 1FL to 1RR, acceleration sensor 18 that detects longitudinal and lateral acceleration generated in the vehicle, and braking fluid that detects braking fluid pressure A pressure sensor 19, an accelerator opening sensor 20 that detects the amount of depression of the accelerator pedal, and a throttle opening sensor 15 that detects the opening of the throttle valve 5 are provided. In addition, this vehicle is provided with a navigation system 7 that detects position information of the vehicle by so-called GPS (Global Positoining System). Further, the vehicle is provided with a display and a speaker 23 for presenting the contents of control by the automatic travel control device 10 to an occupant, particularly a driver.

  Further, this vehicle is provided with a manual switch 9 for adjusting the traveling state of the host vehicle by a driver's manual input. Details of the manual switch 9 are shown in FIG. In the figure, reference numeral 9a is an automatic travel control start switch including travel speed control and preceding vehicle following travel control, 9b is an automatic travel control release switch, 9c is a set inter-vehicle distance switch for inputting a set inter-vehicle distance, and 9d is a set travel. A set / coast switch for inputting a speed or changing a set travel speed in a deceleration direction. 9e is a resume / change switch for re-inputting a previous set travel speed or changing a set travel speed in an acceleration direction after canceling the automatic travel control. Accelerate switch. Of these, the set inter-vehicle distance switch 9c is not used to input a specific set inter-vehicle distance as a numerical value. For example, the set inter-vehicle distance switch 9c is used to increase or decrease the current inter-vehicle distance. When the most standard target inter-vehicle distance with respect to speed is set to “medium”, an input method such as “long” that makes the set inter-vehicle distance larger than that or “short” that makes the set inter-vehicle distance smaller than that is adopted. Yes. However, in the automatic travel control device 10, the set inter-vehicle distance input by the set inter-vehicle distance switch 9c is recognized as the set inter-vehicle distance dc.

  The vehicle travel control apparatus according to the present invention can calculate the travel speed of the host vehicle calculated so that the set inter-vehicle distance and the actual inter-vehicle distance are the same, or the set travel speed set by the manual switch 9d. The travel speed set according to the accelerator opening of the driver is set as the target travel speed, and the acceleration / deceleration of the host vehicle is controlled so that the travel speed of the host vehicle becomes the target travel speed. .

  Next, calculation processing of the inter-vehicle distance control performed in the automatic travel control device 10 will be described with reference to the flowchart of FIG. This calculation process is executed by a timer interrupt every predetermined sampling time ΔT set to, for example, about 10 msec. In this flowchart, no particular communication step is provided, but the results obtained by the arithmetic processing are updated and stored in the storage device as needed, and necessary information and programs are read from the storage device as needed. Further, the above-described engine control device 11, transmission control device 12, and brake fluid pressure control device 13 communicate with each other at any time, and necessary information and commands are exchanged bidirectionally at any time.

In this calculation process, first, in step S1, the longitudinal acceleration Xg and lateral acceleration Yg detected by the acceleration sensor 18, the wheel speed Vw _j (j = FL to RR) detected by the wheel speed sensor 17, and the accelerator opening. The accelerator opening degree Acc detected by the degree sensor 20, the braking fluid pressure Pm detected by the braking fluid pressure sensor 19, the set travel speed Vc set by the manual switch 9, and the self detected by the navigation system 7 The vehicle position information, the inter-vehicle distance d with the preceding vehicle detected by the forward state detection device 16, and the engine drive torque Tw controlled by the engine control device 11 are read.

Next, the process proceeds to step S2, and the traveling speed V of the host vehicle is calculated from the average value of the front left and right wheel speeds Vw _FL and Vw _FR among the wheel speeds Vw _j read in step S1.
Next, the process proceeds to step S3, where the difference value between the current value d _(n) and the previous value d _(n-1) of the inter-vehicle distance read in step S1 is divided by the predetermined sampling time ΔT. Then, the relative speed Vr between the host vehicle and the preceding vehicle is calculated.

  Next, the process proceeds to step S4, and a target inter-vehicle distance dr corresponding to the traveling speed V of the host vehicle calculated in step S2 is calculated. Specifically, the travel speed V of the host vehicle is multiplied by a predetermined control gain, and a predetermined control constant is summed. The control gain and the control constant are set in accordance with the set inter-vehicle distance requested by the driver inputted by the set inter-vehicle distance switch 9c of the manual switch 9.

Next, the process proceeds to step S8, and the target travel speed Vs is calculated according to the following equation (1). That is, first, a value obtained by multiplying the difference value between the actual inter-vehicle distance d read in step S1 and the target inter-vehicle distance dr calculated in step S4 by the inter-vehicle distance feedback proportional control gain Kp is calculated in step S3. A reference target travel speed Vs ₀ is calculated from a value obtained by multiplying the relative speed Vr by the differential control gain Kd and the travel speed V of the host vehicle, and this reference target travel speed Vs ₀ is read in step S1. The smaller of the set travel speeds Vc is set as the target travel speed Vs. Note that min in the equation means minimum value selection.

Next, the process proceeds to step S10, where the target acceleration by, for example, PID (proportional-differential-integral) control is calculated from the difference value between the target traveling speed Vs calculated in step S8 and the traveling speed V of the host vehicle calculated in step S2. Xgs is calculated.
Next, the process proceeds to step S11. For example, when the target acceleration Xgs calculated in step S10 is negative, that is, when deceleration is required, a value obtained by multiplying the target acceleration Xgs by a brake specification coefficient, The larger one of the values obtained by multiplying the braking fluid pressure Pm read in step S1 by the brake specification coefficient is calculated as the target braking fluid pressure Pws _j . The brake specification coefficient is a coefficient determined by, for example, the friction coefficient between the disk rotor pads of each wheel, the wheel cylinder cross-sectional area, the disk rotor effective diameter, the tire rolling radius, and the like.

  Next, the process proceeds to step S12. When the target acceleration Xgs calculated in step S10 is "0" or positive, that is, when acceleration is required, the target acceleration Xgs is multiplied by a drive system specification variable. The larger one of the obtained value and the value obtained by multiplying the accelerator opening Acc read in step S1 by the drive system specification variable is calculated as the target drive torque Tes. The drive system specification variable is a variable determined by, for example, gear inertia, reduction ratio, transmission efficiency, engine characteristics, and the like.

At the next step S13, the step S11 target braking fluid pressure Pws _j and the step S12 the target driving the brake fluid pressure control device a torque Tes 13 and the engine control apparatus 11 calculated in calculated in the transmission control device 12 And output an information presentation signal for target inter-vehicle distance control toward the display and speaker 23, and then return to the main program. For example, when the target distance between the vehicles is changed and controlled, for example, content such as “increase the distance between vehicles” is presented by voice or display before the information is presented by the display and the speaker 23.

According to this calculation process, the target acceleration Xgs is calculated from the difference between the set target travel speed Vs and the travel speed V of the host vehicle, and the target braking fluid pressure Pws _j and target drive for achieving the target acceleration Xgs are calculated. Torque Tes is output to the braking fluid pressure control device 13, the engine control device 11, and the transmission control device 12, and an information presentation signal for target inter-vehicle distance control is output to the display and the speaker 23. Therefore, the engine control device 11 calculates and sets a target throttle opening at which the target drive torque Tes is achieved, and controls the rotation angle of the motor 6 so that the target throttle opening is achieved.

  When the throttle opening is changed in accordance with the inter-vehicle distance control in this way, for example, the value of the throttle opening in the transmission ratio control map shown in FIG. 2 changes, so the transmission ratio is changed even at the same travel speed. Need arises. However, if the gear ratio is controlled in accordance with the throttle opening that is simply changed, the required drive torque cannot be obtained, or the drive torque becomes too large, and the drive torque is corrected. Therefore, if the throttle opening is further changed, the gear ratio must be changed accordingly, and this is repeated to hunt the gear ratio control.

  For example, when the throttle opening is increased in order to increase the drive torque, the coordinates of the throttle opening and the traveling speed exceed the downshift shift line shown in FIG. 2, and as a result, the downshift, that is, the gear ratio is increased. It will change greatly. However, if the gear ratio is increased, the drive torque increases by itself, so that the drive torque becomes excessive with the increase in the throttle opening. In this case, in the inter-vehicle distance control, the throttle opening is reduced to reduce the drive torque. Then, the coordinates of the throttle opening and the traveling speed exceed the upshift shift line shown in FIG. 2, and as a result, the upshift, that is, the gear ratio needs to be changed to be small. If the gear ratio is reduced, the drive torque decreases by itself, so the drive torque becomes too small in accordance with the decrease in the throttle opening in the previous period, and this time the throttle opening is increased. Both gear ratio control and hunting are repeated.

  Therefore, in this embodiment, the throttle opening is limited by the arithmetic processing shown in FIG. 5 so that the gear ratio control is not hunted. The arithmetic processing of FIG. 5 is also executed by timer interruption every predetermined sampling time ΔT set to, for example, about 10 msec. In the automatic travel control device 10 as in the arithmetic processing of FIG. In this flowchart, no particular communication step is provided, but the results obtained by the arithmetic processing are updated and stored in the storage device as needed, and necessary information and programs are read from the storage device as needed. Further, the above-described engine control device 11, transmission control device 12, and brake fluid pressure control device 13 communicate with each other at any time, and necessary information and commands are exchanged bidirectionally at any time.

In this calculation process, first, in step S21, the throttle opening TH detected by the throttle sensor 15 and the traveling speed V calculated in step S2 of the calculation process of FIG. 4 are read.
Next, the process proceeds to step S22, and the engine speed at each gear position (gear position in the figure) is calculated. Specifically, the travel speed V (which may be the driving wheel speed) read in step S21 is divided by the tire circumference (tire rolling radius x 2π), and the gear ratio (reduction ratio) of each gear stage is calculated. Multiply and then multiply the final reduction ratio and torque converter speed ratio as necessary to determine the engine speed.

Next, the process proceeds to step S23, and the engine torque at each gear position (gear position in the figure) is calculated. Specifically, the target drive torque Tes calculated in step S12 of the calculation process of FIG. 4 is multiplied by the gear ratio (reduction ratio) of each gear, and if necessary, the final reduction ratio, torque converter torque ratio, Multiply the gear efficiency and engine gain to find the engine torque.
Next, the process proceeds to step S24, and each speed stage (gear position in the figure) for achieving the engine speed of each speed stage calculated in step S22 and the engine torque of each speed stage calculated in step S23. ) Is calculated from the engine output map of FIG. 6, for example.

Next, the process proceeds to step S25, and a throttle opening limiter (limit) value at each gear position (gear position in the figure) is calculated according to the control table of FIG.
Next, the process proceeds to step S26, and the current gear position (gear position in the figure) is read from the transmission control device 12.
Next, the process proceeds to step S27, in which the throttle opening at each gear position (gear position in the figure) calculated in step S24, the throttle opening limiter value calculated in step S25, and the reading in step S26 are read. However, in accordance with the current gear position (gear position in the figure), a throttle opening limiter process is performed to calculate the throttle opening.
Next, the process proceeds to step S28, the throttle opening calculated in step S27 is output to the transmission control device 12, and then the process returns to the main program.

  Next, the throttle opening limit value setting table of FIG. 7 will be described. The vertical column of this table shows the current gear ratio (gear position in the figure), and the horizontal row shows the throttle opening of the next gear ratio (gear position in the figure). In this embodiment, the throttle opening at each gear ratio (gear position) necessary to obtain the target drive torque is calculated, so the throttle opening when the gear ratio is changed from the current gear ratio is calculated. Can be estimated. For example, the throttle opening when the current gear ratio is 4 and the next gear ratio is 3 is calculated by the calculation process of FIG. 5, and the calculated throttle opening is shown in FIG. It is divided into cases where it is greater than or less than the upshift shift line (3 → 4up line in FIG. 7) from the third stage to the fourth stage (it is considered that the traveling speed does not change).

  For example, when changing from the current four-speed gear ratio to the next three-speed gear ratio, the throttle opening required to obtain the target driving force torque is below the upshift gear line from the third gear to the fourth gear. In this case, if the downshift from the 4th stage to the 3rd stage is allowed, the drive torque increases after the downshift, and the throttle opening is decreased to obtain the target drive torque at the 3rd stage, and the 3rd stage to the 4th stage. Thus, the upshift shift line is crossed, and the upshift is again performed to four stages, and the gear ratio control is hunted. For this reason, in the present embodiment, the downshift shift line from the 5th stage to the 4th stage is set as the accelerator opening limiter value, the downshift from the 4th stage to the 3rd stage is prohibited, and the current 4th speed ratio is set. Like to maintain. In other words, the current gear ratio (fourth gear) and the next gear ratio (three gears) are different, and the throttle opening at the next gear ratio (three gears) crosses the gear line where the current gear ratio is the same. If it is in the position (below the upshift transmission line from the 3rd stage to the 4th stage), it will be upshifted again after the downshift and return to the current transmission ratio, so the current transmission ratio (4th stage) Downshift line (automatic) from 5 to 4 so as not to downshift so that the gear ratio is not changed to the next gear ratio (3 speeds), that is, when the next gear ratio is on the lower gear side than the current gear ratio. The throttle opening is limited with a downshift shift line (which changes the gear ratio of the transmission 3 in the low gear direction) as a limit value. Thus, by setting the downshift shift line from the 5th stage to the 4th stage as the limit value, even if the accelerator opening increases in accordance with the target drive torque, the downshift line from the 4th stage to the 3rd stage. Therefore, the current gear ratio (four steps) is maintained, and hunting of gear ratio control can be suppressed.

  In the present embodiment, in order to maintain the gear ratio of four steps, the limit value of the throttle opening need only be a downshift line from the fourth step to the third step. In short, the limit value of the throttle opening for maintaining the four speed ratio may be any value as long as it is smaller than the downshift line from the fourth speed to the third speed. Also, when the throttle opening required to obtain the target drive torque is larger than the upshift change line from 3 to 4 when the current 4 gear ratio is changed to the next 3 gear ratio. Even when downshifting from 4th to 3rd step, the upshift shift line from 3rd to 4th step is not crossed, so that it is not upshifted to 4th step in a short time. Therefore, in the present embodiment, the accelerator opening limit value is set as a downshift line for shifting from the third speed to the second speed so as to allow the downshift from the fourth speed to the third speed. Here, the accelerator opening limit value is set to a downshift line from 3 to 2 when the current gear ratio is 4 and downshift to the next 3 is allowed. This is to prevent the transmission gear ratio from becoming two steps. That is, the throttle opening is limited using a downshift line from the third speed to the second speed so that the current gear ratio is not downshifted by two speeds or more.

  If the downshift is continuously performed, the gear ratio becomes too large and the throttle opening is excessively decreased, which is not preferable in terms of appropriate inter-vehicle distance control. Therefore, if the throttle opening at the next transmission ratio is larger than the upshift transmission line that returns to the current transmission ratio so that the transmission ratio is not continuously downshifted by two stages or more, the gear ratio is further increased from the next transmission ratio. The downshift line that shifts to the ratio is set as the throttle opening limit value.

  Depending on the accelerator opening at the next gear position estimated in this way, after changing from the current gear ratio to the next gear ratio, the current gear ratio returns to the current gear ratio. After changing to the next gear ratio, if the gear ratio is maintained, and if the gear ratio is changed and returns immediately, the accelerator will not be changed. After limiting the opening and changing the transmission ratio, if the transmission ratio can be maintained, the change in the transmission ratio is allowed, so while suppressing the hunting of the transmission ratio control, Thus, the target drive torque can be obtained, and the travel speed of the host vehicle can be brought close to the target travel speed to perform appropriate inter-vehicle distance control. In addition, when the change of the gear ratio is allowed, the throttle opening is limited so that the gear ratio is not continuously downshifted by two or more stages, so the gear ratio is continuously downshifted by two or more stages. Thus, it is possible to prevent the throttle opening from being excessively reduced and the appropriate inter-vehicle distance control from being performed.

  On the other hand, if the current gear ratio is four steps, the next gear ratio may be five steps. If the gear ratio needs to be upshifted and then the downshift needs to be performed and the gear ratio control is hunting, when performing the inter-vehicle distance control as described above, that is, the preceding vehicle following travel control, It is desirable to upshift the gear ratio and maintain that gear ratio. In the first place, the downshift is necessary because the drive torque needs to be increased. However, if the downshift is not performed, the drive torque is reduced and the traveling speed is reduced. However, in the preceding vehicle following travel control, the throttle opening is increased in order to accelerate the decelerated travel speed, so that the travel speed is maintained as a result (when there is no change in the travel speed). On the other hand, if the upshift is not allowed, the target travel speed cannot be obtained even if the throttle opening is increased, and there is a possibility that appropriate travel speed control cannot be performed. Therefore, in this embodiment, when changing the gear ratio to the high gear (small) side, the downshift gear line from the gear ratio on the high gear (smaller) side to the current gear ratio than the current gear ratio, that is, the gear ratio is changed to the low gear. The shift line to be changed to the (larger) side (downshift shift line from the fifth stage to the fourth stage) is set to the limit value of the throttle opening. As a result, it is possible to reliably prevent the changed gear ratio from being changed again to the downshift side, thereby suppressing the hunting of the gear ratio control, and enabling appropriate inter-vehicle distance control.

  However, since the automatic transmission of this embodiment has five forward speeds, the current gear ratio is five, and the throttle opening when the next gear ratio is four is from four to five. When the speed is equal to or lower than the upshift speed line, that is, when the 5 speed ratio is maintained, the downshift speedline from the 5th speed to the 4th speed is set to the limit value of the throttle opening (the downshift speed line is There is no other way to set the throttle opening limit value).

Further, when the current gear ratio is 1 step and the throttle opening when the next gear ratio is 1 step is larger than the upshift line from 1 step to 2 steps, that is, the 1 step gear ratio is When maintaining, the downshift shift line from the second stage to the first stage is set to the throttle opening limit value (there is no other way to set the downshift shift line to the throttle opening limit value). .
From the above, Steps S21 to S27 of the calculation process of FIG. 5 constitute the throttle opening restriction means of the present invention, and similarly, Step S28 of the calculation process of FIG. 5 constitutes the throttle opening adjustment means. ing.
In the embodiment, each control device is constituted by a microcomputer, but instead of this, an arithmetic processing device may be used as appropriate.

In the above-described embodiment, the stepped automatic transmission with five forward update stages has been described. However, the present invention is not limited to this embodiment, and a stepped automatic transmission or a continuously variable transmission other than the five stages may be used. Good. When a continuously variable transmission is used, a map corresponding to the gear ratio map of the stepped automatic transmission is used to set the gear ratio area and limit value, and the change is made across the set gear ratio area. When the gear ratio returns to the original range again, it is possible to limit the throttle opening so as not to exceed the gear ratio region so as to suppress the hunting of the gear ratio control. .
In the above embodiment, a control device such as a travel speed control device or a preceding vehicle follow-up travel control device is provided as a device that controls the travel state by adjusting the throttle opening, but the travel state is adjusted by adjusting the throttle opening. The device to be controlled is not limited to these.

1 is a system configuration diagram illustrating an example of a vehicle with preceding vehicle follow-up travel control that includes the vehicle travel control device of the present invention. It is explanatory drawing of a gear ratio control map. It is explanatory drawing of the manual switch of FIG. It is a flowchart which shows the arithmetic processing for the inter-vehicle distance control performed with the traveling control apparatus for vehicles of FIG. It is a flowchart which shows the arithmetic processing for throttle opening calculation. 6 is a control map used in the arithmetic processing of FIG. 6 is a control table used in the arithmetic processing of FIG.

Explanation of symbols

1FL to 1RR Wheel 2 Engine 3 Automatic transmission 4FL to 4RR Wheel cylinder 5 Throttle valve 6 Motor 7 Navigation system 9 Manual switch 10 Automatic travel control device 11 Engine control device 12 Transmission control device 13 Brake fluid pressure control device 15 Throttle opening Sensor 16 Forward state detection device 17 Wheel speed sensor 18 Acceleration sensor 19 Brake fluid pressure sensor 20 Accelerator opening sensor 21 Brake pedal 22 Master cylinder 23 Display and speaker

Claims (4)

  Target drive speed setting means for setting the target travel speed of the host vehicle, travel speed detection means for detecting the travel speed of the host vehicle, and target drive torque are calculated so that the travel speed becomes the target travel speed. Target drive torque calculating means, throttle opening adjusting means for adjusting the throttle opening in accordance with the target drive torque, and gear ratio control for controlling the gear ratio of the transmission based on the throttle opening and the travel speed Means for detecting a current gear ratio of the transmission, and a first throttle opening required for obtaining the target drive torque at the current gear ratio. A first throttle opening estimating means for estimating the degree, a first gear ratio estimating means for estimating a first gear ratio from the first throttle opening and the travel speed, and the first gear ratio. The second throttle opening degree estimating means for estimating the second throttle opening degree necessary for obtaining the target drive torque, and the second speed ratio for estimating the second speed ratio from the second throttle opening degree and the traveling speed. 2 speed ratio estimating means, and when the current speed ratio and the first speed ratio are different and the current speed ratio and the second speed ratio are the same, the current speed ratio is A vehicle travel control device comprising throttle opening restriction means for restricting the throttle opening so as not to be changed to the first gear ratio.   The throttle opening restriction means limits the throttle opening so that the transmission does not downshift when the first gear ratio is on the low gear side with respect to the current gear ratio. The vehicle travel control apparatus according to claim 1.   The transmission ratio control means controls the transmission ratio of the transmission based on a transmission line set according to the throttle opening, and the throttle opening restriction means sets the transmission ratio of the transmission on the low gear side. The vehicular travel control apparatus according to claim 1, wherein a downshift shift line that changes in a direction is set as a limit value of the throttle opening.   The throttle opening limiting means limits the throttle opening using the shift line so that when the transmission is stepped, it is not downshifted by two or more stages from the current gear ratio. The vehicle travel control apparatus according to claim 3.

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