JP5458638B2 - Vehicle shift control device - Google Patents

Description

  The present invention relates to a transmission control device for a vehicle.

  In a conventional shift control device, a target deceleration is set according to the radius of curvature of the corner in front of the vehicle, and when the distance between the vehicle and the corner falls below a predetermined threshold, the automatic transmission is downshifted to engine brake. The torque is increased to assist the driver in decelerating when entering the corner. An example of a technique related to this description is disclosed in Patent Document 1.

Japanese Patent Laid-Open No. 2004-10072

However, in the above prior art, since the distance threshold for determining the start timing of the downshift is constant, when the vehicle speed immediately before the downshift is high, the driver feels a sense of incongruity such as a strong feeling of deceleration or a feeling of delay in starting deceleration. There was a problem of giving.
SUMMARY OF THE INVENTION An object of the present invention is to provide a vehicle shift control device that can obtain an appropriate deceleration feeling regardless of the vehicle speed immediately before the downshift, and can reduce the uncomfortable feeling given to the driver.

  In the vehicle transmission control apparatus according to the present invention, the distance threshold for starting the downshift is increased as the target deceleration is higher.

  Therefore, in the present invention, an appropriate deceleration feeling can be obtained regardless of the vehicle speed immediately before the downshift, and the uncomfortable feeling given to the driver can be reduced.

It is the schematic which shows the power train of the front engine front drive vehicle provided with the transmission control apparatus of Example 1 with a deceleration control system. 3 is a flowchart illustrating a flow of deceleration control processing according to the first embodiment. It is an example of the target passing speed calculation map according to the curvature radius (R) of the corner of Example 1. It is an example of the target passing speed calculation map according to the distance to the toll booth of Example 1. It is an example of the target passing speed calculation map according to the distance to the intersection of Example 1. It is an example of the distance threshold value calculation map according to the target deceleration of Example 1. It is an example of the distance threshold value correction coefficient calculation map according to the driving | running tendency and road surface gradient of Example 1. FIG. It is an example of the deceleration correction coefficient calculation map according to the driving | running tendency and road surface gradient of Example 1. FIG. It is an example of the target input rotation speed setting map according to the correction | amendment target deceleration and vehicle speed of Example 1. FIG. It is an example of the target passing lateral acceleration calculation map according to the curvature radius (R) of the corner of another Example.

First, the configuration will be described.
FIG. 1 is a schematic diagram showing a power train of a front engine / front drive vehicle equipped with a speed change control apparatus according to a first embodiment together with a deceleration control system.
The power train of the vehicle of the first embodiment includes an engine 1, a belt type continuously variable transmission (automatic transmission, hereinafter referred to as CVT) 2, a differential 3, left and right drive shafts 4a and 4b, and left and right front wheels 5a and 5b. ing. The output of the engine 1 is decelerated by the CVT 2 and then distributed to the left and right drive shafts 4a and 4b by the differential 3 and transmitted to the left and right front wheels 5a and 5b.

The CVT 2 spans a belt between the primary pulley on the input side and the secondary pulley on the output side, determines the desired pulley width by hydraulically controlling each pulley pressure, and realizes a stepless gear ratio.
The CVT controller (deceleration control means) 6 includes an accelerator opening sensor 7, a brake stroke sensor 8, a primary rotational speed sensor 9, a secondary rotational speed sensor 10, wheel speed sensors 11 a, 11 b, 11 c, 11 d, and an acceleration sensor 12. Input each signal. Further, the road information from the navigation system (deceleration target detecting means) 13 and the ON / OFF signal of the winker switch 14 are input.

The accelerator opening sensor 7 detects the depression amount of the accelerator pedal 15 by the driver in nine stages (0/8, 1/8,..., 8/8).
The brake stroke sensor 8 detects the depression amount of the brake pedal 16 by the driver.
The primary rotational speed sensor 9 detects the rotational speed (input rotational speed) of the primary pulley of the CVT 2. Here, since the input rotational speed is a value obtained by multiplying the engine rotational speed by the speed ratio of the torque converter, the input rotational speed can be regarded as the engine rotational speed.

  The secondary rotational speed sensor 10 detects the rotational speed (output rotational speed) of the secondary pulley of the CVT 2. Here, since the rotational speeds of the left and right front wheels 5a and 5b are values obtained by multiplying the output rotational speed by the gear ratio of the differential 3, the output rotational speed can be regarded as the vehicle speed.

The left front wheel speed sensor 11a detects the rotational speed of the left front wheel 5a. The right front wheel speed sensor 11b detects the rotational speed of the right front wheel 5b. The left rear wheel speed sensor 11c detects the rotational speed of the left rear wheel 5c. The right rear wheel speed sensor 11d detects the rotational speed of the right rear wheel 5d.
The acceleration sensor 12 detects longitudinal acceleration and lateral acceleration acting on the vehicle.
The navigation system 13 provides the vehicle position, road shape, and surrounding information. The turn signal switch 14 is turned on when the driver turns right or left to blink the direction indicator.

The CVT controller 6 sets a target gear ratio based on the accelerator opening from the accelerator opening sensor 7, the input rotation speed from the primary rotation speed sensor 9, and the output rotation speed from the secondary rotation speed sensor 10. A shift actuator drive command corresponding to the target gear ratio is output to the CVT 2. The CVT controller 6 sets the target gear ratio with reference to a shift map in which the horizontal axis represents the vehicle speed, the vertical axis represents the input rotational speed, and the input rotational speed corresponding to the vehicle speed is determined for each accelerator opening.
In addition, when there is a deceleration target (corner, toll road toll gate, intersection, etc.) ahead of the host vehicle from the road information of the navigation system 13, the CVT controller 6 sets a target passing speed suitable for the deceleration target. The target deceleration is calculated according to the current vehicle speed and the distance between the vehicle and the object to be decelerated. When the distance between the vehicle and the object to be decelerated is less than the distance threshold, the CVT2 shift is performed according to the target deceleration. Deceleration control is performed to change the ratio to the downshift side.
In the first embodiment, the following deceleration control is performed with the aim of suppressing the fluctuation of the deceleration due to the difference in vehicle speed immediately before the downshift and reducing the uncomfortable feeling given to the driver.

[Deceleration control processing]
FIG. 2 is a flowchart illustrating the flow of the deceleration control process according to the first embodiment. Each step will be described below. This process is repeatedly executed at a predetermined calculation cycle while the vehicle is traveling.
In step S1, it is determined from the road information of the navigation system 13 whether there is a corner in a predetermined area in front of the vehicle. If YES, the process proceeds to step S2, and if NO, the process proceeds to step S3.

In step S2, the target passing speed Vt corresponding to the corner is calculated, and the process proceeds to step S7. The target passing speed Vt is obtained with reference to the target passing speed calculation map shown in FIG. 3 based on the radius of curvature of the corner R1 selected in step S3. FIG. 3 is an example of a target passing speed calculation map corresponding to the radius of curvature (R) of the corner, and the target passing speed Vt is set so as to increase as the radius of curvature R of the corner increases. Note that a lower limit and an upper limit are set for the target passage speed Vt to prevent the target passage speed Vt from being set too low or too high. The target passing speed Vt is set so that the lateral acceleration when passing the corner is moderate.
Further, the target passing speed Vt is corrected according to the road type of the corner (corresponding to the target passing speed correcting means). For example, when the road type is a road wider than a general road such as an expressway, the target passing speed Vt is set higher than that of the general road. When the number of traveling lanes is large, the target passing speed Vt is set higher than when the number of traveling lanes is small.

In step S3, it is determined from the road information of the navigation system 13 whether there is a toll gate for a toll road such as a highway in a predetermined area in front of the vehicle. If YES, the process proceeds to step S4. If NO, the process proceeds to step S5.
In step S4, a target passing speed Vt corresponding to the toll gate is calculated, and the process proceeds to step S7. The target passage speed Vt is obtained with reference to the target passage speed calculation map shown in FIG. FIG. 4 is an example of a target passing speed calculation map corresponding to the distance to the toll booth, and the target passing speed Vt is set to be higher as the distance to the toll booth becomes longer. Note that a lower limit and an upper limit are set for the target passage speed Vt to prevent the target passage speed Vt from being set too low or too high. The target passing speed Vt is set to a value at which the vehicle speed when passing through the toll gate is moderate. For example, in the case of a manned toll gate, the target passing speed Vt is set to zero [km / h]. In the case of an unmanned toll gate, the target passing speed Vt is set to a predetermined speed that is equal to or less than a predetermined limit speed.

In step S5, it is determined from the road information of the navigation system 13 and the signal of the turn signal switch 14 whether there is an intersection within a predetermined area in front of the vehicle and the driver is willing to turn right or left. If YES, the process proceeds to step S6. If NO, the process proceeds to return.
In step S6, a target passing speed Vt corresponding to the intersection is calculated, and the process proceeds to step S7. The target passage speed Vt is obtained with reference to the target passage speed calculation map shown in FIG. FIG. 5 is an example of a target passing speed calculation map corresponding to the distance to the intersection, and the target passing speed Vt is set to be higher as the distance to the intersection becomes longer. Note that a lower limit and an upper limit are set for the target passage speed Vt to prevent the target passage speed Vt from being set too low or too high. The target passing speed Vt is set to a speed at which the vehicle speed when turning right or left at the intersection is moderate.

In step S7, the target deceleration Gt for the deceleration target (corner, toll booth, intersection) is calculated, and the process proceeds to step S8. The target deceleration Gt is a distance Ln from the host vehicle to the deceleration target calculated from the current vehicle speed V0 calculated from the output rotational speed detected by the secondary rotational speed sensor 10, the target passing speed Vt, and the road information of the navigation system 13. Based on the above, the following formula (1) is used.
Gt = (V0 ² −Vt ² ) / (2 × Ln) (1)
In step S8 (distance threshold setting means), a distance threshold Lt corresponding to the target deceleration Gt is calculated, and the process proceeds to step S9. The distance threshold Lt is obtained with reference to the distance threshold calculation map shown in FIG. FIG. 6 is an example of a distance threshold calculation map corresponding to the target deceleration, and the distance threshold Lt is set to be longer as the target deceleration Gt is larger.

In step S9 (distance threshold correction means, target deceleration correction means), a corrected distance threshold Lc and a corrected target deceleration Gc are calculated by correcting the distance threshold Lt and the target deceleration Gt according to the driving tendency and road gradient of the driver. Then, the process proceeds to step S10.
First, the driving tendency of the driver will be explained. The driving tendency is determined based on the past driving operation (brake, accelerator, steering wheel) of the driver and changes in vehicle behavior (acceleration / deceleration change in the vehicle longitudinal direction, acceleration / deceleration change in the vehicle lateral direction), The driving tendency of the driver is determined in advance as the degree of sports driving (eco driving). The sport running is a driving tendency such that the vehicle speed immediately before the downshift with respect to the deceleration target is increased. For example, when the deceleration control of the first embodiment is not performed, the higher the approach speed to the corner and the passing speed of the corner, or the greater the acceleration / deceleration change of the vehicle when traveling a certain distance, the greater the degree of sport driving The driving tendency is high (low degree of eco-driving). Conversely, the lower the approach speed to the corner and the passing speed of the corner, or the smaller the acceleration / deceleration change of the vehicle when traveling a certain distance, the lower the degree of sport driving (the higher the degree of eco-driving). To do.

In this step S9, the road surface gradient θ is estimated with reference to the following equation (2) based on the vehicle longitudinal acceleration A from the acceleration sensor 12 and the temporal variation (differential value) A ′ of the wheel speed. The wheel speed is an average value of the left rear wheel rotational speed from the left rear wheel speed sensor 11c and the right rear wheel rotational speed from the right rear wheel speed sensor 11d.
θ ＝ sin ^-1 {(A-A ') / g} (2)
Here, g is a gravitational acceleration.
In addition, the estimation method of a road surface gradient is not restricted to the said method, Arbitrary methods can be used.

Next, a distance threshold correction coefficient Kl is calculated. The distance threshold correction coefficient Kl is obtained with reference to the distance threshold correction coefficient calculation map shown in FIG. FIG. 7 is an example of a distance threshold correction coefficient calculation map according to the driving tendency and the road surface gradient θ, and the distance threshold correction coefficient Kl increases as the degree of sport driving increases (the degree decreases as the degree of eco driving increases). To do). Further, the distance threshold correction coefficient Kl is set to a larger value as the road surface gradient θ is larger in the case of a downhill road, and to a smaller value as the road surface gradient θ is larger in the case of an uphill road.
The distance threshold value Lc is calculated by multiplying the distance threshold value correction coefficient Kl by the distance threshold value Lt.

Next, a deceleration correction coefficient Kd is calculated. The deceleration correction coefficient Kd is obtained with reference to the deceleration correction coefficient calculation map shown in FIG. FIG. 8 is an example of a deceleration correction coefficient calculation map according to the driving tendency and the road surface gradient θ, and the deceleration correction coefficient Kd is increased as the degree of the sport running is higher. In other words, the higher the degree of eco-driving, the smaller. Further, the deceleration correction coefficient Kd is set to a larger value as the road surface gradient θ is larger in the case of a downhill road, and is set to a smaller value in the case of an uphill road as the road surface gradient θ is larger.
A correction target deceleration Gc is calculated by multiplying the target deceleration Gt by the deceleration correction coefficient Kd.

In step S10, it is determined whether or not the correction distance threshold Lc is greater than zero. If YES, the process proceeds to step S11. If NO, the process proceeds to return. Here, the reason for terminating the present control process when NO (negative determination) is that when the correction distance threshold Lc is equal to or less than zero, the correction target deceleration Gc is very small and it is not necessary to increase the engine brake torque. .
In step S11, it is determined whether or not the distance Ln to the deceleration target is equal to or less than the correction distance threshold Lc. If YES, the process proceeds to step S12. If NO, the process proceeds to step S1.
In step S12, it is determined whether or not the accelerator is in a coasting (inertia running) state based on whether or not the accelerator opening detected by the accelerator opening sensor 7 is 0/8. If YES, the process proceeds to step S13. If NO, the process proceeds to step S1.

  In step S13, the target input rotational speed Net is calculated from the corrected target deceleration Gc and the current vehicle speed V1, and the process proceeds to step S14. The target input rotational speed Net is obtained with reference to a target input rotational speed setting map as shown in FIG. FIG. 9 is an example of a target input speed setting map corresponding to the corrected target deceleration and the vehicle speed. The target input speed Net is increased as the vehicle speed V1 is higher or the corrected target deceleration Gc is higher. The target input rotational speed Net is set with a rotational speed upper limiter (upper limit value) corresponding to the vehicle speed to suppress an excessive increase in engine speed. This is to prevent the driver from feeling uncomfortable or annoying such as sound and vibration.

In step S14, it is determined whether or not the target input rotational speed Net is higher than the current input rotational speed Nen. If YES, the process proceeds to step S15. If NO, the process proceeds to return.
In step S15, the target speed ratio Rt is calculated from the target input rotational speed Net and the current vehicle speed Vn, and CVT2 speed change control (downshift) is executed so as to achieve the target speed ratio Rt, and the process proceeds to step S16.
In step S16, it is determined whether or not the current input rotational speed Nen matches the target input rotational speed Net. If YES, the process proceeds to return, and if NO, the process proceeds to step S13.

Next, the operation will be described.
In the conventional speed change control device, based on the road information from the navigation system, the target passing speed is set according to the radius of curvature of the corner ahead of the vehicle, the intersection, and the distance to the toll gate on the toll road, and the current vehicle speed and target The target deceleration is calculated from the difference from the passing speed, and the necessity of deceleration control for the deceleration target is determined according to the target deceleration. Here, when it is determined that deceleration control is necessary, the shift stage of the automatic transmission is shifted to the downshift side when the distance between the deceleration target and the host vehicle reaches a predetermined distance threshold. This increases the engine brake torque and assists the driver in decelerating the deceleration target.

At this time, in the conventional speed change control device, the distance threshold value for starting the downshift with respect to the object to be decelerated is set to a constant value. Therefore, when the vehicle speed immediately before the downshift is high, the deceleration of the vehicle increases and the driver Give a sense of incongruity such as a strong feeling of deceleration and a delay in starting deceleration.
Even when the target deceleration is constant for the deceleration target, the deceleration amount deviates from an appropriate value depending on the road condition (road slope θ, road type) and the driving tendency of the driver. In particular, in a vehicle equipped with a continuously variable transmission capable of continuously selecting a gear ratio as an automatic transmission, if a constant target deceleration is always set for a deceleration target, the driver feels uncomfortable.

[Distance threshold setting action according to target deceleration]
On the other hand, in the deceleration control of the first embodiment, in step S7, the target deceleration Gt based on the target passing speed Vt corresponding to the deceleration target, the current vehicle speed V0, and the distance Ln between the host vehicle and the deceleration target. In step S9, the distance threshold Lt is increased as the target deceleration Gt is higher. For this reason, the higher the target deceleration Gt, the longer the distance Ln between the vehicle that starts the downshift and the deceleration target. That is, the higher the target deceleration Gt, the earlier the downshift start timing.
For example, when executing deceleration control with an intersection as an object of deceleration, the target deceleration Gt is larger when the vehicle speed is high than when the vehicle speed is low. That is, since the demand for deceleration is high, it is necessary to start downshift earlier in order not to give the driver a strong sense of deceleration. Therefore, by increasing the distance threshold Lt as the target deceleration Gt increases, it is possible to execute a downshift at an optimal timing in response to a deceleration request, so a moderate deceleration feeling is provided regardless of the vehicle speed immediately before the downshift. It can be obtained and the uncomfortable feeling given to the driver can be reduced.

[Distance threshold correction according to driving tendency]
In step S9, the distance threshold correction coefficient Kl is calculated according to the driving tendency determined from the driving operation of the driver, and the distance threshold correction coefficient Kl is multiplied by the distance threshold Lt to calculate the correction distance threshold Lc. Then, when the distance Ln to the deceleration target is equal to or less than the correction distance threshold Lc, the accelerator OFF determination is made in step S12, and when the current input rotational speed Nen is determined to be smaller than the target input rotational speed Net in step S14, Proceeding to step S15, downshift is started.
For example, even when the vehicle passes through the same corner at the same vehicle speed, the vehicle speed before entering the corner is high when the driving tendency is sports driving, and therefore downshifting earlier is suitable for sports driving. Therefore, it is possible to decelerate the vehicle at a timing suitable for sports driving by applying a correction according to the driving tendency of the driver to the distance threshold Lt which is a threshold for permitting downshift, and allowing downshift earlier. it can.
On the other hand, if you downshift at the same position (same timing) as during sports driving when driving slowly, such as eco-friendly driving, the downshift timing will be too early and the vehicle will decelerate excessively, making the driver uncomfortable. I will give it. Therefore, by permitting a downshift later during eco-driving, the vehicle can be decelerated at a timing suitable for eco-driving.

[Distance threshold correction according to road slope]
The distance threshold correction coefficient Kl is set to a larger value when the road surface gradient θ is larger in the case of a downhill road, and is set to a smaller value as the road surface gradient θ is larger in a case of an uphill road.
For example, even when passing the same corner at the same vehicle speed, the slope resistance is greater on an uphill road than on a flat road. Too early to give the driver a sense of incompatibility Therefore, on the uphill road, the vehicle can be decelerated at a timing suitable for the uphill road by permitting the downshift later than the flat road.
Conversely, in the case of a downhill road, the vehicle is in a direction to accelerate, so it is better to start deceleration earlier. Therefore, on downhill roads, by allowing downshifts earlier than flat roads, the vehicle can be decelerated at a timing suitable for downhill roads.

[Target deceleration correction action according to driving tendency]
In step S9, the deceleration correction coefficient Kd is calculated according to the driving tendency determined from the driving operation of the driver, etc., and the target deceleration Gt is calculated by multiplying the deceleration correction coefficient Kd by the target deceleration Gt, and corrected. Based on the target deceleration Gc, the target input rotational speed Net of CVT2 is calculated.
For example, even if the vehicle passes through the same corner at the same vehicle speed, the required deceleration amount is large because the vehicle speed before entering the corner is high when the driving operation is sport running. Therefore, by correcting the target deceleration Gt so as to increase the deceleration amount during sports running, it is possible to secure an engine brake torque suitable for sports running.
On the other hand, if the engine brake torque is the same as that during sports driving when driving slowly, such as eco-driving, the engine brake will be too effective or the engine speed will increase too much, giving the driver a sense of discomfort. . Therefore, by correcting the target deceleration Gt so that the deceleration amount becomes smaller during eco-driving, engine brake torque suitable for eco-driving can be secured.
Incidentally, in the first embodiment, since a continuously variable transmission is adopted as an automatic transmission, the amount of deceleration can be freely selected. However, in the case of a stepped transmission in which the gear ratio is limited, it is reduced during sports driving. By making it easy to shift and making it difficult to downshift during slow driving such as eco-driving, the same effects as in the case of a continuously variable transmission can be obtained.

[Target deceleration correction action according to road slope]
The deceleration correction coefficient Kd is set to a larger value as the road surface gradient θ is larger in the case of a downhill road, and to a smaller value as the road surface gradient θ is larger in the case of an uphill road.
For example, even if the vehicle passes through the same corner at the same vehicle speed, the slope resistance is larger on an uphill road than on a flat road, so that a deceleration force is not so necessary. Therefore, in the case of an uphill road, by making the deceleration amount small so that it is difficult to decelerate, it is possible to avoid giving the driver a sense of incongruity due to excessive braking.
Conversely, in the case of a downhill road, the vehicle is in a direction to accelerate, so it is better that the deceleration force is strong. Therefore, in the case of a downhill road, a deceleration suitable for the driving operation of the driver can be obtained by increasing the deceleration amount to facilitate the deceleration.
By the way, when a stepped transmission is adopted as an automatic transmission, it is easy to downshift when traveling downhill, and difficult to downshift when traveling uphill, so the same effect as in the case of a continuously variable transmission is achieved. Can be obtained.

[Target speed correction function according to road type]
In step S2, the target passing speed Vt passing through the corner is corrected according to the road type.
For example, even if the curvature radius is the same, the vehicle speeds that can be passed are different between a wide road and a narrow road. Moreover, since the vehicle speed zones are different between the highway and the general road, it is necessary to vary the target passing speed even at the same corner depending on the type of the traveling road. Therefore, by changing the target passage speed Vt according to the road type, it is possible to set the target passage speed Vt suitable for the road width and the vehicle speed zone.

[Target speed ratio setting action according to target deceleration]
In step S13, the target input speed Net is set according to the target deceleration Gt. In step S15, the target speed ratio Rt of the CVT 2 is calculated according to the current vehicle speed Vn and the target input speed Net. And appropriate deceleration according to the target deceleration Gt can be secured. At this time, since the upper limit value of the target input rotational speed Net is limited by the rotational speed upper limiter, it is possible to prevent the engine rotational speed from rising and to ensure an appropriate deceleration force. When the target deceleration Gt is high, if the required deceleration is achieved only by the CVT 2 shift, the engine speed becomes too high, which gives the driver an uncomfortable feeling. This can be avoided by setting a rotation speed upper limiter.

[Action to avoid downshift when going straight at intersection]
In step S5, only when the driver indicates an intention to make a right or left turn at the intersection, the process proceeds to step S6 to calculate a target passing speed Vt, and when the driver does not indicate an intention to make a right or left turn, the control is terminated. Do not downshift. If you downshift when going straight at the intersection, the driver will feel uncomfortable, so avoid this.

Hereinafter, other operations will be described.
In step S11, when the distance Ln to the deceleration target is larger than the correction distance threshold Lc, the process returns to step S1 without downshifting, and the correction distance threshold Lc and the correction target deceleration Gc are updated (reset). The reason is that if the corrected distance threshold Lc and the corrected target deceleration Gc are not updated until Ln ≦ Lc is satisfied, the distance Ln to the controlled object will be shortened, and the vehicle speed V0 will change with the driver's acceleration / deceleration operation This is because the correction distance threshold Lc and the correction target deceleration Gc set this time deviate from appropriate values. Therefore, when Ln> Lc, the target speed ratio Rt that matches the vehicle speed V0 and the distance Ln to the control target can be set by updating the correction distance threshold Lc and the correction target deceleration Gc.
In step S12, the coasting state in which the accelerator is OFF is determined. If the accelerator is ON, the downshift is not performed. If a downshift is performed while the driver is performing an accelerator operation, the driver will feel uncomfortable due to unexpected driver deceleration.

Next, the effect will be described.
The speed change control device for a vehicle according to the first embodiment has the following effects.
(1) Calculate the target deceleration Gt corresponding to the detected deceleration object, the navigation system 13 for detecting the deceleration object in front of the vehicle, the CVT 2 interposed between the engine 1 and the left and right front wheels 5a and 5b, When the distance Ln between the host vehicle and the object to be decelerated is less than the distance threshold Lt, the CVT controller 6 changes the gear ratio of the CVT 2 to the downshift side according to the target deceleration Gt, and the higher the target deceleration Gt, the greater the distance Distance threshold setting means (step S8) for increasing the threshold Lt. Thereby, it is possible to obtain an appropriate deceleration feeling regardless of the vehicle speed immediately before the downshift, and to reduce the uncomfortable feeling given to the driver.

  (2) Since there is a distance threshold correction means (step S9) for determining a driving tendency (sport driving, eco driving) based on the driving operation of the driver and correcting the distance threshold Lt according to the determined driving tendency, The vehicle can be decelerated at a timing suitable for the driving tendency.

  (3) On the uphill road, the distance threshold Lt is decreased as the road surface gradient θ is larger. On the downhill road, the road surface gradient θ is provided with distance threshold correction means (step S9) that increases the road surface gradient θ as the road surface gradient θ is larger. The vehicle can be decelerated at a suitable timing.

  (4) Since it has a target deceleration correction means (step S9) that determines the driving tendency based on the driving operation of the driver and corrects the target deceleration Gt according to the determined driving tendency, it is suitable for the driving tendency of the driver Engine brake torque can be secured.

  (5) The road surface is provided with a target deceleration correction means (step S9) that decreases the target deceleration Gt as the road surface gradient θ increases on an uphill road and increases the target deceleration Gt as the road surface gradient θ increases on a downhill road. An engine brake torque suitable for the gradient θ can be secured.

  (6) When the object to be decelerated is a corner, it has target passage speed correction means (step S2) that corrects the target passage speed Vt based on the road type of the corner. Speed Vt can be set.

  (7) Since the CVT controller 6 changes the gear ratio of the CVT 2 so that the target input speed Net according to the vehicle speed Vn and the target deceleration Gt is obtained, an appropriate deceleration according to the vehicle speed Vn and the target deceleration Gt is achieved. Can be secured.

  (8) Since the CVT controller 6 limits the target input rotational speed Net with a predetermined rotational speed upper limiter, it can prevent the engine rotational speed from rising and ensure an appropriate deceleration force.

  (9) When the deceleration target is an intersection, the CVT controller 6 changes the gear ratio of the CVT 2 according to the target deceleration Gt only when the driver's intention to turn left or right is detected by the ON signal from the turn signal switch 14 . That is, when the driver intends to go straight through the intersection, the downshift is not performed, so that the driver can be prevented from feeling uncomfortable by decelerating the vehicle when going straight through the intersection.

(Other examples)
The best mode for carrying out the present invention has been described above based on the embodiments. However, the specific configuration of the present invention is not limited to the embodiments and is within the scope of the invention. Any design changes are included in the present invention.
For example, in the embodiment, an example is shown in which the target passing speed is set according to the size of the corner in front of the vehicle. However, as shown in FIG. 10, the target lateral acceleration may be used instead of the target passing speed. . In this case, the lateral acceleration estimated value generated at the time of passing is calculated from the current vehicle speed and the radius of curvature of the front corner, and based on the difference between the target lateral acceleration and the lateral acceleration estimated value and the distance between the vehicle and the corner. To calculate the target deceleration.
In the first embodiment, a continuously variable transmission is shown as an example of an automatic transmission. However, the present invention can also be applied to a vehicle equipped with a stepped transmission, and the same effects as those of the first embodiment can be obtained. .

1 Engine 2 CVT (automatic transmission)
5a, 5b Front left and right wheels (drive wheels)
6 CVT controller (deceleration control means)
10 Navigation system (deceleration target detection means)

Claims (8)

A deceleration target detecting means for detecting a deceleration target in front of the vehicle;
An automatic transmission interposed between the engine and the drive wheel;
A target deceleration corresponding to the detected deceleration target is calculated, and when the distance between the host vehicle and the deceleration target is equal to or less than a distance threshold, the automatic transmission is configured so that the target transmission ratio is obtained to obtain the target deceleration. Deceleration control means for changing the gear ratio to the downshift side;
Distance threshold setting means for increasing the distance threshold as the target deceleration is higher;
Driving tendency to determine that the higher the approach speed to the object to be decelerated or the greater the acceleration / deceleration change of the vehicle when traveling a certain distance is, the higher the driver's driving tendency is sport driving and the lower the eco driving condition. A determination means;
Target deceleration correction means for increasing and correcting the target deceleration as the degree of driving tendency is sport driving, and decreasing and correcting the target deceleration as the degree of driving tendency is eco driving; and
A shift control apparatus for a vehicle, comprising:

The vehicle shift control device according to claim 1,
A shift control apparatus for a vehicle, comprising: a distance threshold correction unit that determines a driving tendency based on a driving operation of a driver and corrects the distance threshold according to the determined driving tendency. The vehicle shift control device according to claim 1 or 2,
A speed change control device for a vehicle, comprising: a distance threshold correction unit that decreases the distance threshold as the road gradient increases on an uphill road, and increases the distance threshold as the road gradient increases on a downhill road. The vehicle shift control device according to any one of claims 1 to 3,
A vehicle shift control device comprising target deceleration correction means for decreasing the target deceleration as the road gradient increases on an uphill road and increasing the target deceleration as the road gradient increases on a downhill road. The shift control apparatus for a vehicle according to any one of claims 1 to 4,
The deceleration control means calculates the target deceleration based on the target passing speed according to the deceleration target, the current vehicle speed, and the distance between the host vehicle and the deceleration target,
When the object to be decelerated is a corner, the vehicle transmission control apparatus includes target passing speed correcting means for correcting the target passing speed based on a road type of the corner. The vehicle shift control device according to any one of claims 1 to 5,
The automatic transmission is a continuously variable transmission,
The speed change control device for a vehicle, wherein the speed reduction control means changes a gear ratio of the automatic transmission so that a target input rotational speed corresponding to a vehicle speed and a target deceleration is obtained. The shift control apparatus for a vehicle according to claim 6 ,
The speed reduction control means limits the target input rotation speed by a predetermined upper limit value, and a gear shift control device for a vehicle. The vehicle shift control device according to any one of claims 1 to 7 ,
When the deceleration target is an intersection, the deceleration control means changes the gear ratio of the automatic transmission to the downshift side according to the target deceleration only when the driver's intention to turn left or right is detected. A speed change control device for a vehicle.

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