JP3562758B2 - Downshift indicator for automatic transmission - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a shift-down instruction device for instructing a shift-down of an automatic transmission in accordance with a traveling situation ahead of a vehicle, and more particularly to a shift-down execution determination performed in a situation where deceleration is required.
[0002]
[Prior art]
A technique has been proposed in which a traveling situation ahead of a vehicle is grasped based on navigation information and preview information obtained from a preview sensor, and deceleration is performed by downshifting as necessary. For example, Japanese Unexamined Patent Publication Nos. Hei 8-2021989 and Hei 8-194886 disclose that when a road ahead of the vehicle is curved, the vehicle speed when entering the curved road is too high, that is, overspeed. If it is determined that the vehicle is going down a curve, a technique for executing a downshift is disclosed. In this way, by decelerating in advance just before entering a curve, it is possible to realize a good curve traveling property without giving a feeling of strangeness to the driver.
[0003]
[Problems to be solved by the invention]
However, even if the downshift is performed for the purpose of deceleration, the own vehicle may accelerate depending on the state of the vehicle at that time. FIG. 10 is a diagram showing, as an example, a characteristic line that can be decelerated by downshifting from fourth speed to third speed in the relationship between vehicle speed υ and throttle opening θ. While the vehicle is traveling on a flat road, if the downshift is performed in a region (vehicle speed υ, throttle opening θ) below the illustrated characteristic line, the vehicle decelerates (deceleration shift down). However, if the downshift is performed in a region above the characteristic line, the vehicle accelerates (accelerated downshift). When downshifting is performed for deceleration in preparation for entering a curve, if the acceleration downshift is performed, the original purpose of deceleration cannot be achieved. Further, when a preceding vehicle exists in front of the own vehicle, there is a possibility that the inter-vehicle distance from the preceding vehicle may be sharply reduced due to the acceleration shift down, and thus there is a safety problem.
[0004]
The present invention has been made in view of such a problem, and an object of the present invention is to further improve the safety and reliability of a device that controls the behavior of a vehicle according to monitoring outside the vehicle.
[0005]
[Means for Solving the Problems]
In order to solve such a problem, the present invention provides a downshift instruction device for an automatic transmission, a recognition unit for recognizing a running situation ahead of the vehicle based on preview information, and a deceleration based on a recognition result of the recognition unit. Instruction means for instructing a downshift when it is determined that the situation should be reached. Here, the instructing means is configured not to instruct the downshift when it is determined that the vehicle accelerates due to the downshift even in a situation where the vehicle should be decelerated.
[0006]
Here, when it is determined that the own vehicle is accelerated by the downshift, it is preferable that the instruction unit suspends the downshift instruction until it determines that the own vehicle does not accelerate by the downshift.
[0007]
Further, it is preferable that the instructing means determines whether or not it is a situation to decelerate, based on a curve existing ahead of the vehicle and the vehicle speed of the vehicle.
[0008]
Further, it is desirable that the instructing means determines whether or not it is in a situation to decelerate based on a positional relationship between the own vehicle and a preceding vehicle existing in front of the own vehicle.
[0009]
On the other hand, the instruction means may determine whether or not the own vehicle accelerates after the downshift based on the vehicle speed, the throttle opening, and the gear ratio after the downshift. At this time, a running resistance calculating means for calculating the running resistance of the own vehicle is further provided, and it is determined whether or not the own vehicle accelerates after downshifting, taking into account the running resistance calculated by the running resistance calculating means. Is preferred. Further, a road gradient calculating means for calculating a road gradient at the position of the vehicle is further provided, and it is determined whether or not the vehicle accelerates after downshifting in consideration of the road gradient calculated by the road gradient calculating means. desirable.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a block diagram showing the overall configuration of a transmission system using the downshift instruction device according to the present embodiment. The microcomputer 1 serving as the shift-down instruction device includes vehicle state signals (vehicle speed υ, engine speed NE, throttle opening θ, etc.) obtained from the sensors 2 to 5, navigation information obtained from the navigation unit 6, and A shift signal P indicating the current set shift speed, which is information output from the transmission control unit (TCU) 7, is input. The microcomputer 1 recognizes the running condition ahead of the vehicle based on the input information, and outputs instruction signals DOWN and TRGT to the TCU 7 to decelerate according to the recognition result. When a downshift is instructed by these instruction signals DOWN and TRGT, the TCU 7 temporarily suspends the shift control in the normal mode, and performs the shift control according to the instruction (shift down mode).
[0011]
FIG. 6 is a flowchart showing a shift control procedure performed in the TCU 7. First, in step 51, the TCU 7 reads the downshift instruction signal DOWN and determines whether or not this instruction signal DOWN is at the "1" level, that is, whether or not execution of downshift is instructed. In a normal traveling state, the downshift instruction signal DOWN is set to the “0” level. Therefore, as long as the downshift instruction signal DOWN is “0”, the shift control in the normal mode in step 52, that is, the shift is performed based on the shift map based on the vehicle speed υ and the throttle opening θ as shown in FIG. The stage GR is set. Then, the TCU 7 outputs an engagement control signal for setting the gear position of the automatic transmission 9 (hereinafter, referred to as AT) to the gear position GR to the hydraulic control circuit 8 (Step 54). The hydraulic control circuit 8 operates each solenoid constituting the hydraulic control mechanism 9a in the AT 9 according to an instruction by the engagement control signal. As a result, each friction engagement element (clutch or brake) constituting the friction engagement mechanism 9b in the AT 9 is engaged / disengaged, and the AT 9 shifts to the shift speed (for example, four forward speeds, one reverse speed) specified by the TCU 7. Is set.
[0012]
On the other hand, if the downshift instruction signal DOWN is at the "1" level, that is, if downshift execution is instructed (step 51), the shift setting in the downshift mode is performed (step 53). In this mode, the shift stage GR is forcibly set (that is, without reference to the shift map shown in FIG. 9) to the target shift stage TRGT (specified by the instruction signal TRGT from the microcomputer 1). Then, the TCU 7 outputs an engagement control signal for setting the shift speed of the AT 9 to the shift speed GR, that is, the target shift speed TRGT, to the hydraulic control circuit 8 (step 54).
[0013]
The vehicle speed sensor 2, the engine speed sensor 3, and the throttle opening sensor 4 are well-known sensors used for calculating the vehicle speed υ, the engine speed NE, and the throttle opening θ, respectively. Further, the preview sensor 5 is a sensor that outputs a running situation ahead of the vehicle as preview sensor information. In this embodiment, a well-known stereo image processing apparatus including a pair of CCD cameras and an image processing system is used as the preview sensor 5. Based on a pair of captured images obtained from each CCD camera, it is possible to obtain three-dimensional position information including the distance to an object (preceding vehicle or road shape) existing ahead. In addition, as the preview sensor 5, a monocular camera, a sensor using a millimeter wave or a laser wave, or a sensor using them in combination may be used in addition to the stereo image processing device.
[0014]
The navigation unit 6 outputs the navigation information including the position, the traveling direction, the road shape, and the like of the vehicle using the GPS technology and the road map information stored in a storage medium such as a CD-ROM or a DVD. The microcomputer 1 matches the preview sensor information from the preview sensor 5 with the navigation information from the navigation unit 6 and uses the matched information as “preview information” (that is, for recognizing the running situation ahead of the vehicle). The information used directly for the vehicle) ensures the reliability of recognition of the running situation ahead of the vehicle.
[0015]
FIG. 2 is a flowchart illustrating a main routine of a deceleration instruction according to the present embodiment. The microcomputer 1 repeatedly executes a series of procedures shown in the flowchart at predetermined intervals. First, in step 1, preview information and various sensor information υ, NE, θ, etc. are read.
[0016]
Next, the traveling state ahead of the vehicle is recognized based on the preview information and the navigation information (step 2). Specifically, the three-dimensional road shape, the presence or absence of a preceding vehicle, the distance between the host vehicle and the preceding vehicle (inter-vehicle distance), and the like are recognized. An important matter to be recognized in relation to the present embodiment is detection of a curve existing ahead. As a pattern forming one curve, there are a case where the curve is formed by a single node as shown in FIG. 11 and a case where the curve is formed by a plurality of nodes as shown in FIG. The information on these nodes can be obtained from the navigation information, and includes the coordinate information of discrete points on the road with respect to the own vehicle. The road shape is expressed as a polygonal line by a line connecting adjacent nodes.
[0017]
The nodes Pj-1 (coordinates (x [j-1], y [j-1])) and Pj (coordinates (x [j], y [j])) adjacent to each other are basically the following two. If the conditions are satisfied, it is determined that the nodes Pj−1 and Pj belong to the same curve.
[0018]
(Same curve condition)
1. Distance L [j] between adjacent nodes Pj-1 and Pj is smaller than a predetermined value
2. The signs of the node angles t [j-1] and t [j] of the adjacent nodes Pj-1 and Pj are the same
[0019]
Here, the distance L [j] between the nodes Pj is calculated by the following equation.
(Equation 1)
L [j] = ｛(x [j] −x [j−1])²+ (Y [j] -y [j-1])²｝^1/2
The node angle t [j] of the node Pj is calculated by the following equation.
(Equation 2)
t [j] = sin^-1[｛(X [j-1] -x [j]) (y [j] -y [j + 1])-(x [j] -x [j + 1]) (y [j-1] -y [j] )｝ / (L [j] L [j + 1])]
[0020]
From the same curve conditions, it is determined that the nodes P1, Pj-1, Pj, and Pj + 1 shown in FIG. 11 form separate curves. Further, it is determined that the node groups Pj-1 to Pj + 2 shown in FIG. 12 form one curve.
[0021]
In step 3 following step 2, the determination speed Vth according to the forward curve shape is calculated. The determination speed Vth indicates the upper limit value of the vehicle speed allowed at the current position of the vehicle in relation to the shape of the curve ahead, and is used for the determination when performing the deceleration determination (possibility of downshifting) in step 5. Used as a threshold. FIG. 3 is a flowchart showing a detailed calculation procedure of the determination speed Vth in step 3.
[0022]
First, a road surface friction coefficient μ (hereinafter referred to as a road surface μ) of a road and a road gradient SL are estimated (step 11). The road surface μ can be estimated based on the yaw rate, the steering angle, the lateral acceleration, and the vehicle speed, for example, as disclosed in JP-A-8-2274. The method for calculating the road gradient SL will be described later.
[0023]
In step 12 following step 11, the maximum value of the deceleration that does not cause a slip on a certain road surface μ, that is, the allowable deceleration β is calculated. The allowable deceleration β can be obtained by correcting the value specified using the road surface μ calculated in step 11 as a basic parameter using the road gradient SL calculated in step 11 as well. It should be noted that a specific calculation method of the allowable deceleration β is disclosed in Japanese Patent Application Laid-Open No. H11-83501, and therefore, should be referred to if necessary.
[0024]
Then, the target node Ptrgt and the allowable approach speed Vap of the target node Ptrgt are calculated for the forward curve specified in step 2 described above (step 13). Here, the “target node Ptrgt” refers to a node having the smallest curve curvature radius in one curve. The vehicle speed that can be allowed when entering a certain curve existing ahead of the vehicle may be set based on a node that should decelerate and pass the most because the radius of curvature is minimum. Therefore, in the road shape shown in FIG. 11, each node P1, Pj-1, Pj, Pj + 1 forming a separate curve is a target node Ptrgt. In the road shape shown in FIG. 12, among the node groups Pj-1 to Pj + 2 forming one curve, the node Pj-1 having the smallest radius of curvature is the target node Ptrgt in the curve. The curve radius of curvature r [j] at a certain node Pj can be calculated based on three points including the preceding and following nodes Pj−1 and Pj + 1.
[0025]
Based on the specified radius of curvature of the target node Ptrgt, the approach speed Vap allowed to pass through the target node Ptrgt is calculated by the following method. First, prior to calculating the allowable approach speed Vap, the allowable lateral acceleration gv is calculated. When passing through a curve, the limit value of the lateral acceleration becomes smaller as the road surface μ becomes smaller. Also, even at the same vehicle speed, the lateral acceleration increases as the radius of curvature of the curve decreases. Based on such knowledge, the lateral acceleration can be calculated using the road surface μ and the curve radius of curvature of the target node Ptrgt as basic input variables. Then, the allowable lateral acceleration gv is calculated by correcting the calculated lateral acceleration with the road gradient SL. Note that a detailed calculation method of the allowable lateral acceleration gv is disclosed in Japanese Patent Application Laid-Open No. H11-83501.
[0026]
The allowable approach speed Vap can be calculated from the allowable lateral acceleration gv and the curve radius of curvature rtrgt of the target node Ptrgt by the following equation. As can be seen from the equation, the smaller the allowable lateral acceleration or the smaller the radius of curvature of the curve, the smaller the speed allowed when entering the curve.
(Equation 3)
Vap = (gv × rtrgt)^1/2
[0027]
This value may be corrected according to the depth of the curve or the road width, and the corrected value may be used as the allowable approach speed Vap. In this case, the allowable approach speed Vap is set to decrease as the curve depth increases or the road width decreases.
[0028]
In step 14 following step 13, a determination speed Vth indicating the upper limit of the vehicle speed at the current position of the vehicle is calculated from the allowable approach speed Vap at the target node Ptrgt. When the distance from the current position to the target node Ptrgt (the distance is L) is reduced by K% (for example, 50%) of the allowable deceleration β, the determination speed Vth reaches the target node Ptrgt. Sometimes, the vehicle speed is equal to the allowable approach speed Vap. As an example, the determination speed Vth can be obtained by the following equation.
(Equation 4)
Vth = (Vap²) + 2 × (K × β) L)^1/2
[0029]
As described above, if the allowable approach speed Vap for the curve ahead, the distance L to the target node Ptrgt, and the allowable deceleration β can be specified, the upper limit value (determination speed Vth) of the vehicle that the own vehicle can take at the current position is determined. Back calculation is possible. Then, in a later step 5, by comparing the vehicle speed に お け る at the current position with the determination speed Vth, it is determined whether or not the vehicle speed 過 is excessive relative to the entry of the curve, that is, the necessity of deceleration is determined.
[0030]
In step 4 following step 3, it is determined whether or not the deceleration execution flag FDS is "1". The deceleration execution flag FDS is initially set to "0". Therefore, the process proceeds from step 4 to step 5 when the flag FDS is "0".
[0031]
In step 5, it is determined whether it is a situation to be decelerated. Specifically, the determination speed Vth calculated in step 3 is compared with the current vehicle speed 算出 calculated by the vehicle speed sensor 2. If the vehicle speed で is equal to or lower than the determination speed Vth, it is determined that it is possible to enter a forward curve at the current vehicle speed と も without decelerating. Therefore, in this case, the process proceeds from the negative determination in Step 5 to Steps 9 and 11, and the “0” level downshift instruction signal DOWN is output to the TCU 7. The shift-down instruction signal DOWN is normally set to the “0” level (instructing a shift control in the normal mode) unless there is a special driving situation in which deceleration must be performed automatically. Upon receiving the downshift instruction signal DOWN at the “0” level, the TCU 7 performs shift control in the normal mode (step 52).
[0032]
On the other hand, if an affirmative determination is made in step 5, that is, if the vehicle speed 大 き い is greater than the determination speed Vth, it is determined that the current vehicle speed υ is excessively large in order to safely enter a forward curve. In this case, it is determined that deceleration is necessary, and the routine proceeds to step 6, where it is determined whether or not downshifting is performed in order to perform deceleration before entering the curve.
[0033]
FIG. 4 is a flowchart showing a detailed procedure of the shift down determination in step 6. First, in step 21, the target shift speed TRGT after downshift is set. As the target shift speed TRGT, in all ranges including the D range, a shift speed is set as one paragraph from the current shift speed (for example, if the current shift speed is 4th, 3rd speed). Further, in the case of the D range and the current shift speed is the fourth speed (or third speed), the third speed (or second speed) may be set as the target shift speed TRGT. Further, the target shift speed TRGT may be set to one or two shift stages from the current shift speed according to the required degree of deceleration. Further, a method of changing the shift mode itself is also possible. For example, if the current shift mode is the D range, it may be reduced to three ranges.
[0034]
Steps 22 to 26 are procedures for estimating the acceleration α (predicted acceleration) that would occur when downshifting to the target gear position TRGT. First, in step 22, based on the current engine speed NE calculated from the sensor 3 and the current throttle opening θ calculated from the sensor 4, referring to the engine torque calculation map shown in FIG. The current output torque Tq is calculated. In step 23 following step 22, the predicted driving force F of the engine after the downshift is calculated from the current output torque Tq and the gear ratio Rtrgt of the target shift speed TRGT based on the following equation. Here, Rfinal is a final gear ratio (constant), and C is a tire radius (constant).
(Equation 5)
F = Tq × Rtrgt × Rfinal / C
[0035]
In step 24 following step 23, the running resistance r, that is, the resistance received when the vehicle travels back in the air, is calculated from the current vehicle speed υ calculated from the sensor 2 by the following equation. Here, the constant A is the entire projected area, the constant Cd is the air resistance coefficient, and the constant ρ is the air density.
(Equation 6)
r = A × Cd × 1 / 2ρ × υ²
[0036]
Then, in step 25, the road gradient SL is calculated based on the current vehicle speed υ and the current generated driving force F (note that this is the driving force at the shift speed before downshifting). FIG. 5 is a flowchart showing a detailed procedure for estimating the road gradient. First, in step 41, the generated driving force F at the current gear P is calculated from the current output torque Tq calculated in step 22 and the gear ratio R of the current gear P in the same manner as in the above-described formula 5. It is determined by the formula.
[0037]
Next, in step 42, the road gradient SL is calculated from the current vehicle speed υ and the current generated driving force F calculated in step 41 with reference to the road gradient estimation map shown in FIG. The road gradient estimation map shows a change in the generated driving force F with respect to the vehicle speed に for each road gradient. Therefore, if the current vehicle speed υ and the generated driving force F are specified, the road gradient SL at that time can be estimated.
[0038]
In step 26 following step 25, the target drive speed TRGT is determined based on the predicted drive force F [N] (the drive force at the target shift speed TRGT after downshifting), the running resistance r [N], and the road gradient SL [degree]. The acceleration α (predicted acceleration after downshift) is calculated by the following equation. Note that the constant g in the equation is a gravitational acceleration.
(Equation 7)
α = F / W- (r / W-g × sinSL)
[0039]
Then, in step 27, it is determined whether or not the predicted acceleration α after downshift is positive. That the acceleration α> 0 means that if the downshift is executed in the current vehicle state, the vehicle will accelerate against the original intention of deceleration. Therefore, in this case, the process proceeds from step 27 to step 28, and the downshift instruction signal DOWN is maintained at the "0" level (downshift execution is not possible). Upon receiving the downshift instruction signal DOWN at the “0” level, the TCU 7 continues the shift control in the normal mode without shifting to the downshift mode (step 52). In other words, even if the traveling state requires deceleration, downshifting is not performed because the vehicle is accelerated by downshifting in the current vehicle state.
[0040]
On the other hand, the fact that the acceleration α ≦ 0 indicates that the vehicle does not accelerate even if the downshift is performed. Therefore, in this case, the process proceeds from step 27 to step 29, in which a downshift instruction signal DOWN at the "1" level (shift down execution permission) is output to TCU7. Then, the deceleration execution flag FDS is set to "1" (step 30). Upon receiving the downshift instruction signal DOWN at the "1" level, the TCU 7 temporarily suspends the normal mode and shifts to the downshift mode (step 53). Thus, downshifting to the target gear position TRGT is performed.
[0041]
Next, a procedure for releasing the deceleration instruction will be schematically described. When a shift down instruction is given in a certain cycle, the deceleration execution flag FDS is set to "1" in step 30 in that cycle. Therefore, in the next cycle, the procedure from step 4 to step 7 is executed. First, in step 7, it is determined whether or not the situation to decelerate is gone. This determination is made based on the passage of a curve including the target node Ptrgt, the running state of the own vehicle, and the like. If a negative determination is made in step 7 (for example, if the vehicle has not yet passed through the curve), the process proceeds to steps 10 and 11, and a "1" level downshift instruction signal DOWN is output to the TCU 7. Therefore, the shift-down mode is not released, so that the shift speed of AT9 is maintained at the target shift speed TRGT (that is, the downshift state is maintained). Until the situation where deceleration is not required, the downshift instruction signal DOWN is maintained at the "1" level, so that the mode does not return to the normal mode.
[0042]
On the other hand, when it is no longer necessary to decelerate, the process proceeds from step 7 to step 8 in that cycle, and an instruction to release the downshift is issued. That is, the downshift instruction signal DOWN switches from the “1” level to the “0” level, and the deceleration execution flag FDS is reset to “0” (steps 8 and 11). As a result, the mode is returned from the downshift mode to the normal mode, and normal shift control is resumed (step 52 in FIG. 6).
[0043]
As can be understood from the above description, in a driving situation where there is no need to decelerate, a series of steps 1 to 5, 9, and 11 is executed, and thus a downshift instruction is not output (step 6 is skipped). . On the other hand, when the driving situation requires deceleration, a series of steps 1 to 5, 6, and 11 is executed, and therefore, it is determined whether the downshift is performed. In this case, as shown in the flowchart of FIG. 4, the downshift is not performed in the vehicle state where the acceleration downshift occurs, and the downshift is suspended until the vehicle state changes to the state where the acceleration downshift does not occur. . That is, in a driving situation where deceleration is required, it is determined whether or not an acceleration downshift occurs, and the downshift is executed only when it is determined that the vehicle does not accelerate.
[0044]
As described above, in the present embodiment, it is possible to avoid the occurrence of the acceleration downshift immediately before the curve, which is a problem in the conventional downshift instruction device. Therefore, there is no fear of giving the driver a feeling of anxiety. Further, by preventing the acceleration shift down, it is possible to prevent the inter-vehicle distance from the preceding vehicle from being sharply reduced in a situation where the preceding vehicle exists in front of the own vehicle. For these reasons, there is an effect that the safety and reliability of the vehicle behavior control according to the monitoring outside the vehicle can be further improved.
[0045]
In the above-described embodiment, the deceleration control in a situation where a curve is present in front of the own vehicle has been described. However, it is preferable that the deceleration control is performed in combination with the alarm control (to alert the driver). . For example, if the current vehicle speed に 対 し て is excessive with respect to a curve ahead, an alarm is first sounded to prompt the driver to decelerate. Then, when the driver does not perform deceleration by the brake operation or when the deceleration is insufficient, deceleration control by downshifting may be performed.
[0046]
In the above-described embodiment, the deceleration control caused by the curve ahead of the vehicle has been described. However, the present invention is not limited to this, and can be widely applied to various driving situations where deceleration control can be performed. For example, the present invention may be applied to deceleration control in which a downshift is performed in accordance with the inter-vehicle distance from a preceding vehicle. In this case, instead of calculating the determination speed Vth in step 3 of FIG. 2, the determination inter-vehicle distance Dth is calculated according to the following equation.
(Equation 8)
Dth = (current vehicle speedυ [m / s] × idle running time A [sec] + margin B [m]) × (− (relative speed [m / s] × coefficient C + margin D)
[0047]
Here, the relative speed can be calculated from the preview sensor information obtained from the preview sensor 5 based on a change in the inter-vehicle distance from the preceding vehicle per unit time. When the current inter-vehicle distance becomes smaller than the determined inter-vehicle distance Dth, it is determined that the vehicle should be decelerated, and deceleration is performed by downshifting as described in the above-described embodiment.
[0048]
【The invention's effect】
As described above, according to the present invention, it is possible to avoid a situation in which the vehicle is accelerated by downshifting in a traveling situation in which a preceding vehicle exists in front of the own vehicle. Therefore, the safety and reliability of the device that controls the behavior of the vehicle according to the monitoring outside the vehicle can be further improved.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an overall configuration of a transmission system using a downshift instruction device according to an embodiment;
FIG. 2 is a flowchart showing a main routine of a deceleration instruction according to the embodiment;
FIG. 3 is a flowchart showing a procedure for calculating a determination speed.
FIG. 4 is a flowchart showing a procedure for determining whether downshifting is possible or not.
FIG. 5 is a flowchart showing a procedure for estimating a road gradient;
FIG. 6 is a flowchart showing a shift control procedure.
FIG. 7 shows an example of an engine torque calculation map.
FIG. 8 shows an example of a road gradient estimation map.
FIG. 9 shows an example of a shift map.
FIG. 10 is an example of a characteristic diagram showing an upper limit of a throttle opening that can be decelerated and shifted down with respect to a vehicle speed;
FIG. 11 is an explanatory diagram of one curve constituted by a single node;
FIG. 12 is an explanatory diagram of one curve composed of a plurality of nodes;
[Explanation of symbols]
1 shift-down indicating device (microcomputer),
2 vehicle speed sensor, 3 engine speed sensor,
4 Throttle opening sensor, 5 Preview sensor,
6 Navigation unit,
7 Transmission control unit (TCU),
8 hydraulic control circuit, 9 automatic transmission (AT),
9a hydraulic control mechanism, 9b friction engagement mechanism

Claims (8)

In a shift down instruction device of an automatic transmission,
Recognition means for recognizing a running situation ahead of the vehicle based on preview information obtained by matching preview sensor information from the preview sensor with navigation information from the navigation unit;
If it is determined that it is a situation to be decelerated based on the recognition result in the recognition means, the instructing means to determine whether to instruct the execution of downshift,
The instruction means,
If it is determined that the vehicle is decelerating downshifting when the downshifting is performed in the situation where deceleration is to be performed, an instruction is given to execute the downshifting,
A shift-down instruction device for an automatic transmission, wherein if the shift-down is executed in the situation where the vehicle is to be decelerated, the shift-down instruction device does not give an instruction to execute the shift-down when the vehicle is accelerated. In a shift down instruction device of an automatic transmission,
Recognition means for recognizing a running situation in front of the vehicle;
If it is determined that it is a situation to be decelerated based on the recognition result in the recognition means, the instructing means to determine whether to instruct the execution of downshift,
The instruction means,
If it is determined that the vehicle is decelerating downshifting when the downshifting is performed in the situation where deceleration is to be performed, an instruction is given to execute the downshifting,
A shift-down instruction device for an automatic transmission, wherein if the shift-down is executed in the situation where the vehicle is to be decelerated, the shift-down instruction device does not give an instruction to execute the shift-down when the vehicle is accelerated. 3. The method according to claim 1, wherein the instruction unit suspends the instruction to perform the downshift until it determines that the vehicle does not accelerate due to the downshift when the downshift is determined to be the acceleration downshift. 4. Downshift instruction device for automatic transmission. 4. The vehicle according to claim 1, wherein the instruction unit determines whether the vehicle should be decelerated based on a curve existing ahead of the vehicle and a vehicle speed of the vehicle. 5. Downshift indicating device of automatic transmission. 4. The method according to claim 1, wherein the instructing unit determines whether or not the vehicle should be decelerated based on a positional relationship between the vehicle and a preceding vehicle located ahead of the vehicle. 5. A shift-down instruction device for an automatic transmission according to claim 1. 3. The method according to claim 1, wherein the instructing unit determines whether or not the acceleration downshift is performed, based on a vehicle speed, a throttle opening, and a speed ratio after downshifting. 4. Downshift instruction device for automatic transmission. The vehicle further includes running resistance calculation means for calculating running resistance of the vehicle,
The shift of the automatic transmission according to claim 6, wherein the instructing unit determines whether or not the acceleration shift down is performed in consideration of the running resistance calculated by the running resistance calculating unit. Down indication device. A road gradient calculating means for calculating a road gradient at the own vehicle position,
8. The automatic transmission according to claim 6, wherein the instructing unit determines whether or not the acceleration shift down is performed in consideration of the road gradient calculated by the road gradient calculating unit. 9. Downshift indicating device.

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