JP3804120B2 - Control device for automatic transmission - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an automatic transmission control device, and more particularly, to an automatic transmission control device improved so that unnecessary downshifts do not frequently occur due to depression of an accelerator pedal during climbing.
[0002]
[Prior art]
In general, a control device for an automatic transmission mounted on a vehicle determines a gear position by applying these two actually measured values to a shift map in which vehicle speed and throttle opening are set as parameters in advance, as well as a clutch, a band brake, etc. The power transmission paths of the plurality of friction elements are automatically switched to realize the above-described shift stage.
[0003]
In this case, as the shift map, firstly, a shift map for traveling on a flat road, which is characterized so that a shift change is performed at an appropriate timing on a flat road, is used. However, as disclosed in, for example, Japanese Patent Application Laid-Open No. 5-71626, this flat road map does not provide appropriate speed change characteristics when traveling uphill or downhill. It is also known to use a shift map for uphill / downhill travel in which the 4-3 shift line is changed to the high vehicle speed side, the 4th speed region is reduced, and the 3rd speed region is expanded, in addition to the flat road map. Yes. According to this, when traveling on an uphill / downhill road, the tendency to shift down from the 4th speed to the 3rd speed increases, and as a result, the driving force increases in the case of uphill, and the engine brake is utilized in the case of downhill. Thus, good speed change characteristics that cannot be obtained with the flat road map are realized.
[0004]
[Problems to be solved by the invention]
However, in such conventional shift control, the following problems occur when the vehicle approaches an uphill road, particularly a gentle uphill road, from a flat road.
[0005]
That is, the flat road map is generally based on a so-called road load line that represents the relationship between the throttle opening and the vehicle speed at which the vehicle can be driven at a constant speed while keeping the vehicle speed constant, and is not intended to be accelerated by the driver, for example. It is created in consideration of a slight operation range such as unconscious operation of the accelerator pedal. That is, as conceptually shown in FIGS. 10 and 11, the shift line c is set to the operation width d after adding the above-described operation width d to the load / load line a when the gradient is 0 °. The position is set so as not to enter. Therefore, assuming that the vehicle is currently traveling on a flat road at a vehicle speed v, the throttle opening is at the position “a”, and even if an unintentional accelerator operation or the like is performed here, the speed change is not performed. Does not happen.
[0006]
On the other hand, let us consider a case where the vehicle enters a long and gentle uphill from a flat road, which is often seen on, for example, a highway. Then, it is assumed that the driver determines that the vehicle can be fully climbed while maintaining the current gear position, and that the accelerator pedal is depressed so as not to decrease the vehicle speed with respect to a gentle uphill inclination. This accelerator operation is not intended to obtain a greater driving force for acceleration, but, as described above, is intended to maintain the same vehicle speed v as that on a flat road on this uphill. The degree rises to the position of symbol a, but does not exceed the shift line c. However, in this state, in other words, when the above-described unintentional accelerator operation or the like is performed on the load / load line b at a gentle slope, the throttle opening may increase beyond the shift line c. As a result, downshifting easily occurs.
[0007]
  And thisDownshiftSince the speed change is not intended by the driver, it is difficult for the driver to run, the drive feeling is hindered, and the passenger feels uncomfortable from the standpoint of quietness.
[0008]
  Furthermore, as indicated by the symbol e in FIG. 11, in the uphill control as disclosed in the above publication, the shift-down shift line is changed to the high vehicle speed side, so the shift-down line e, The throttle opening a, which is stepped on to maintain the same vehicle speed v as that on a flat road, will be closer, and the above problems will occur more frequently, and depending on the setting of the uphill map, Thus, when the downshift line e is changed to the higher vehicle speed side and the throttle opening a exceeds the downshift line e, and therefore the accelerator pedal is depressed to maintain the vehicle speed.DownshiftA shift can occur.
[0009]
  Therefore, the present invention addresses the above-described problems in the conventional automatic transmission control device, and is unnecessary due to the accelerator pedal depressing operation when the vehicle approaches the uphill road from the flat road. NaDownshiftThe challenge is to prevent frequent shiftsAt the same time, it is a challenge to realize shift control that can respond to acceleration requests on uphill roadsAnd
[0010]
[Means for Solving the Problems]
In order to solve the above problems, the present invention is specified as follows.
[0011]
  That is, the invention according to claim 1 (hereinafter referred to as “first invention”) of the present invention is the driving state of the vehicle.And shift mapIs a control device for an automatic transmission that automatically switches the shift speed based onA slope detecting means for detecting the slope of the uphill road sometimes, and when the slope of the uphill road detected by the detecting means is greater than a first predetermined value, the shift map for the downshift in the shift map is from when traveling on a flat road. By using the low speed lineShift down regulation means to make it difficult to shift downWhen the downshift occurs when the slope of the uphill road detected by the detecting means is larger than the second predetermined value that is larger than the first predetermined value, the vehicle travels on a flat road as a shift-up shift line in the shift map. Shift-up regulating means that makes it difficult to shift up by using a shift line on the higher vehicle speed sideAnd is provided with
[0012]
  According to the first aspect of the present invention, when the vehicle is traveling uphill, the slope of the uphill road isWhen greater than the first predetermined value, a shift line on the lower vehicle speed side than when traveling on a flat road is used as a shift line for downshifting in the shift map,Since downshifting is unlikely to occur, even if the driver depresses the accelerator pedal so that the vehicle speed does not decrease with respect to the ascending slope, or if the driver performs the accelerator operation unconsciously, Unnecessary to the driverDownshiftOccurrence of shifting is suppressed, and driving comfort and quietness that meet the needs of the driver can be obtained.
[0013]
  When a downshift occurs when the slope of the uphill road is larger than a second predetermined value that is greater than the first predetermined value, the shift line on the higher vehicle speed side than when traveling on a flat road is used as a shift up shift line in the shift map. Therefore, it is less likely to shift up to a gear position before downshifting than when traveling on a flat road.
[0014]
  In other words, when going uphill, first of all, a downshift regulation is performed to suppress the occurrence of unnecessary downshifts not intended by the driver, but the accelerator pedal depressing operation intended to accelerate beyond this downshift regulation. In this case, the shift-up shift line when the shift-down restriction is not activated, in other words, the shift line on the higher vehicle speed side than the shift-up shift line when traveling on a flat road is used. As a result, the upshift regulation becomes stricter and the upshift is less likely to occur than when traveling on a flat road. This up-shift regulation is the same control as the conventional uphill control. In other words, this first invention is necessary while suppressing the occurrence of unnecessary downshifts not intended by the driver during uphill driving. If so, the control shifts to the same climbing control as before so that a larger driving force is applied. As a result, when the driver is operating the accelerator to such an extent that the vehicle speed is not reduced with respect to the ascending slope, driving with the current gear stage is achieved, and driving and quietness can be obtained. When the accelerator pedal is depressed further in the hope of acceleration, the control shifts to climbing control, and driving at low gears and increase in driving force over a long period of time are achieved, thereby satisfying the driver's needs, and more A more precise two-stage shift control is realized.
[0015]
  next,Claim 2Described in the following (hereinafter “Second invention" ) Above1st inventionIn the shift down regulation means,When it is detected that the slope of the uphill road is larger than the first predetermined value,Shift-down shift line in shift mapTheAs a shift-down shift line by correcting to the low vehicle speed sideFrom running on a flat roadShift line on the low vehicle speed sideThe shift-up restricting means is used for correcting the shift-up by correcting the shift-up shift line in the shift map to the high vehicle speed side when a downshift occurs when the slope of the uphill road is larger than the second predetermined value. Shift lines on the higher vehicle speed side than when traveling on flat roadsIt is characterized by using.
[0016]
  thisSecond inventionAccording toThe shift-down restriction and the shift-up restriction in the first invention are respectively executed by correcting the shift-down shift line to the low vehicle speed side and correcting the shift-up shift line to the high vehicle speed side in the shift map. .
[0017]
  next,Claim 3Described in the following (hereinafter “Third invention" ) Above1st inventionIn the shift down regulation means,When it is detected that the slope of the uphill road is larger than the first predetermined value,Shift mapShift down shift line from shift map for flat roadBy switching to the shift map set on the low vehicle speed side, as a shift down shift lineFrom running on a flat roadShift line on the low vehicle speed sideThe shift-up restricting means is used to set the shift map on the higher vehicle speed side than the shift map for the flat road when the downshift occurs when the slope of the uphill road is larger than the second predetermined value. By switching to the changed shift map, the shift line on the higher vehicle speed side than when traveling on a flat road is used as a shift-up shift line.It is characterized by using.
[0018]
  thisThird inventionAccording toThe downshift regulation and the upshift regulation in the first invention are executed by switching the shift map.
[0032]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0033]
As shown in FIG. 1, in the vehicle in this embodiment, the left and right front wheels 1 and 2 are driven wheels, the left and right rear wheels 3 and 4 are drive wheels, and the output torque of the engine 5 is a torque converter 6 and a transmission gear. The power is transmitted to the left and right rear wheels 3 and 4 via the output shaft 9 of the automatic transmission 8, the differential device 10, and the left and right drive shafts 11 and 12 via the automatic transmission 8 formed in combination with the mechanism 7. It is like that.
[0034]
Further, a throttle valve 13 is provided in the intake system of the engine 5, and when the accelerator pedal 14 is depressed, the opening degree of the throttle valve 13 is adjusted, and the intake air amount is variably controlled to control the engine output. It is like that.
[0035]
The vehicle includes an engine rotation sensor 15 that detects the rotation speed of the output shaft 5 a of the engine 5, a turbine rotation sensor 16 that detects the rotation speed of the turbine shaft 6 a of the torque converter 6, and an output shaft 9 of the automatic transmission 8. 2 and a throttle opening sensor 18 for detecting the opening of the throttle valve 13, and based on various signals input from these sensors, FIG. A control unit 20 is provided that outputs a shift signal to the transmission 19 of the automatic transmission 8 in accordance with any one of the control programs shown in FIGS. Hereinafter, the shift control shown in each of the above drawings will be sequentially described.
[0036]
First, in the shift control shown in FIG. 2, a plurality of different shift maps are stored in advance in the control unit 20 according to the road gradient, and the shift map is switched and used based on the detection result of the road gradient. Is.
[0037]
That is, the control unit 20 reads various signals such as the engine speed NE, the turbine speed TREV, the vehicle speed VSP, and the throttle opening THVOL (step S11). In this case, as the vehicle speed VSP, the vehicle speed VSP obtained from the rotational speed of the output shaft 9 of the automatic transmission 8 based on the gear ratio of the differential device 10, the tire circumference, etc. may be used. What was calculated | required based on the gear ratio of the transmission gear mechanism 7, the gear ratio of the differential gear 10, the tire circumference, etc. from TREV may be used.
[0038]
Next, the control unit 20 calculates a road surface gradient value grade (step S12). The calculation of the road surface gradient value grade is performed generally as follows. That is, the control unit 20 obtains the output torque of the engine 5 from the engine speed NE and the throttle opening THVOL, and obtains the turbine torque from the engine torque and the torque ratio of the torque converter 6. Further, an expected acceleration obtained when traveling on a flat road is calculated from the turbine torque based on the weight of the vehicle body and the like. On the other hand, the control unit 20 obtains the actual acceleration of the vehicle from the time change of the vehicle speed VSP. Then, the predicted acceleration and the actual acceleration are compared, and if both are substantially equal, it is determined that the road is a flat road, if the latter is larger than the former, it is determined as a downhill road, and if the former is larger than the latter, it is determined as an uphill road. Accordingly, the road surface gradient value grade is calculated.
[0039]
Next, the control unit 20 determines whether or not the road surface gradient value grade obtained in this way is greater than a predetermined value A (step S13). In this case, the predetermined value A is set to a relatively small slope angle, for example, 3 °, etc., among the gentle uphill angles at which it is determined that the vehicle can keep climbing while maintaining the current speed. Is set. If NO, that is, if it is determined that the vehicle is traveling on a flat road, the shift pattern A for flat road shown in FIG. 3 is selected (step S14), and shift determination based on the shift pattern A is performed. (Step S19).
[0040]
On the other hand, when the road surface gradient value grade is larger than the predetermined value A, it is further determined whether or not the road surface gradient value grade is larger than the predetermined value B (step S15). Here, the predetermined value B is set to a gradient angle equal to or greater than the predetermined value A, for example, 5 °. If NO, that is, if it is determined that the vehicle is traveling on an uphill road having a relatively small slope angle, the shift pattern B shown in FIG. 4 is selected (step S16). Based on this, a shift determination is made (step S19).
[0041]
  Further, when the road surface gradient value grade is greater than the predetermined value B, that is, when it is determined that the vehicle is traveling on an uphill road having a relatively large gradient angle,DownshiftIs determined (step S17). If YES, the shift pattern C shown in FIG. 5 is selected (step S18), and the shift determination based on the shift pattern C is performed (step S19). In the case of NO, the shift pattern B is selected (step S16).
[0042]
At this time, as shown in FIG. 3 to FIG. 5, the shift pattern A is set so that each shift line is set so as to realize a smooth shift on a flat road. Compared to the flat road shift pattern A, the 3-2 shift down line and the 2-1 shift down line are set on the low vehicle speed side, and the shift pattern C is all compared to the flat road shift pattern A. The shift line is set on the high vehicle speed side.
[0043]
  Therefore, according to this shift control, when the vehicle is traveling on a flat road (in the above example, the gradient angle is 3 ° or less), the shift pattern A is used and a shift change suitable for the flat road is performed. On the other hand, when the vehicle is traveling on an uphill road and the gradient angle is relatively small (in the above example, the gradient angle is greater than 3 ° and less than 5 °), the shift pattern B is used,DownshiftIs unlikely to occur. As a result, even if the driver depresses the accelerator pedal so as not to decrease the vehicle speed with respect to this relatively small gentle slope, or even if the driver unconsciously performs further accelerator operation, the driver's intention Don't needDownshiftShifting is suppressed, and ease of driving and quietness that meet the needs of the driver can be obtained.
[0044]
  Similarly, when the vehicle is traveling on an uphill road and the gradient angle is relatively large (in the above example, the gradient angle is greater than 5 °), the shift pattern is similarly changed until the downshift occurs. B is used,DownshiftHowever, when the driver depresses the accelerator pedal for this relatively large gentle slope to request acceleration, and as a result, a shift down occurs, the shift pattern C is used and the driver is flat. Than when driving on the roadShift upWill be difficult to occur.
[0045]
  In other words, according to this shift control, when driving uphill, it is unnecessary and unnecessary for the driver.DownshiftDepending on the driver's accelerator operation, it is necessary to suppress the occurrence of gear shifting with priority.if there isThus, the shift control is the same as the conventional climbing control so that a larger driving force is applied. This makes it easy to drive and quiet when the driver is operating the accelerator slightly so that the vehicle speed is not reduced, and the low gear position when the driver depresses the accelerator pedal greatly in hopes of acceleration. Thus, the two-stage shift control that closely matches the needs of the driver is realized.
[0046]
Next, the shift control shown in FIGS. 6 to 7 is basically the same flow as the shift control shown in FIG. 2 except that the shift line is changed according to the detection result of the road surface gradient instead of switching the shift map. Is used after correction.
[0047]
  That is, after reading various signals (step S21), the control unit 20 calculates a road surface gradient value grade (step S22) in the same manner as described above, and whether or not the road surface gradient value grade is greater than a predetermined value A. Is determined (step S23). If NO, that is, if it is determined that the vehicle is traveling on a flat road, the process proceeds to step S24, and 1-2.Shift upFor 2-3Shift up3-2DownshiftAnd 2-1.DownshiftVehicle speed predetermined value F for each shift₁₂, F₂₃, F₃₂, F₂₁Ask for. These shift vehicle speed predetermined values F₁₂, F₂₃, F₃₂, F₂₁Is a function f of the throttle opening THVOL.₁₂, F₂₃, F₃₂, F₂₁It is set to a value that realizes a smooth shift when the vehicle is traveling on a flat road.
[0048]
  On the other hand, when the road surface gradient value grade is larger than the predetermined value A, it is further determined whether or not the road surface gradient value grade is larger than the predetermined value B (step S25). In the case of NO, that is, the vehicle is relatively small. If it is determined that the vehicle is traveling on an uphill road with a slope angle, the process proceeds to step S26, and each vehicle speed predetermined value F₁₂, F₂₃, F₃₂, F₂₁In this case, 3-2DownshiftAnd 2-1.DownshiftVehicle speed predetermined value F₃₂, F₂₁Is calculated by multiplying a predetermined positive value α less than 1. As a result, these 3-2DownshiftAnd 2-1DownshiftVehicle speed predetermined value F₃₂, F₂₁Is set to a lower value than when traveling on a flat road, that is, on the low vehicle speed side.
[0049]
  Further, when the road surface gradient value grade is greater than the predetermined value B, that is, when it is determined that the vehicle is traveling on an uphill road having a relatively large gradient angle,DownshiftIs determined (step S27), if YES, the process proceeds to step S28, and each vehicle speed predetermined value F is also determined.₁₂, F₂₃, F₃₂, F₂₁In this case, these predetermined values F₁₂, F₂₃, F₃₂, F₂₁Are all multiplied by a predetermined positive value β greater than 1. As a result, each shift vehicle speed predetermined value F₁₂, F₂₃, F₃₂, F₂₁Is set to a higher value than when traveling on a flat road, that is, on the high vehicle speed side.
[0050]
Then, in steps S29 to S36, the current gear stage gear and the above-mentioned predetermined vehicle speed values F for shifting.₁₂, F_{twenty three}, F₃₂, F_{twenty one}From the magnitude relationship of the vehicle speed VSP with respect to, the gear stage gear is shifted up or down one by one, and the determined gear stage gear signal is output to the transmission 19 of the automatic transmission 8.
[0051]
Therefore, according to this shift control, when the vehicle is traveling on a flat road, the shift vehicle speed predetermined value F₁₂, F_{twenty three}, F₃₂, F_{twenty one}However, when the vehicle is traveling on an uphill road with a relatively small slope angle, the 3-2 shift down line and the 2-1 shift down line are low. When the vehicle is set on the vehicle speed side and the vehicle is traveling on an uphill road having a relatively large slope angle, all the shift lines are set on the high vehicle speed side, and thus, the same as the shift control shown in FIG. The effect of is obtained.
[0052]
  Note that the shift control shown in FIG. 8 is a control example related to the present invention.Such shift map switching and shift line correction are not performed, and even if the throttle opening exceeds the shift line, the shift is not permitted until the increment reaches a predetermined amount.
[0053]
That is, the control unit 20 reads various signals in the same manner as described above (step S41), calculates the road gradient value grade (step S42), and determines whether or not the road gradient value grade is greater than a predetermined value A. Is determined (step S43). In the case of NO, that is, when it is determined that the vehicle is traveling on a flat road, the process proceeds to step S44, and the predetermined value TVX with respect to the increment after the throttle opening exceeds the shift line is set to zero. On the other hand, if YES, that is, if it is determined that the vehicle is traveling on an uphill road, the routine proceeds to step S45, where the predetermined value TVX is determined according to the vehicle speed VSP.
[0054]
Then, the control unit 20 determines whether or not the throttle opening increment δ is larger than the predetermined value TVX (step S46). If NO, no shift is executed (step S47). If YES, Shifting is executed (step S48).
[0055]
  Therefore, according to this shift control, when the vehicle is traveling on a flat road, the predetermined value TVX is set to 0, so that the shift is immediately executed when the throttle opening exceeds the shift line, and the normal shift control is performed. On the other hand, when the vehicle is traveling on an uphill road, even if the throttle opening exceeds the shift line, the shift is not immediately performed, and the throttle opening increment δ exceeds the predetermined value TVX. The gear shift is executed only when it becomes large. As a result, when running uphill, the conditions for executing gear shifting become stricter.Speed changeIs delayed and shift down is less likely to occur.
[0056]
In this shift control, it is not necessary to correct the downshift line or switch the shift characteristics.
[0057]
  Further, according to this shift control, when the throttle opening increment reaches a predetermined value, the downshift is permitted. This is because when the driver depresses the accelerator pedal so much, it is reasonable not to simply maintain the vehicle speed but to determine that he is actively demanding acceleration and demanding driving force. So in such a caseDownshiftThe speed is changed to give a larger driving force. As a result, shift control that more closely matches the needs of the driver is realized.
[0058]
By the way, as described above, the vehicle speed VSP can be obtained from the rotational speed of the output shaft 9 of the automatic transmission 8 and from the turbine rotational speed TREV. In particular, a value obtained from the turbine rotational speed TREV is used. When the gradient value grade is calculated in the above steps S12, S22, S42, the following problem arises.
[0059]
That is, in order to determine the vehicle speed VSP from the turbine rotational speed TREV, the turbine shaft 6a needs to be directly connected to the output shaft 9 of the automatic transmission 8, but during the speed change, the friction element in the transmission gear mechanism 7 is required. While the fastening state is in the transition period and the power transmission path is changing, the rotational ratio relationship between the turbine shaft 6a and the output shaft 9 is broken. Therefore, even during gear shifting, if the vehicle speed VSP is calculated from the turbine rotational speed TREV and the actual acceleration of the vehicle is obtained from this, the gradient value becomes an abnormal value, and the above-mentioned shift control becomes inaccurate.
[0060]
Therefore, as shown in FIG. 9, various signals are read in step S11, S21, or S41. Next, in step S51, it is determined whether or not a shift is being performed. It is preferable to calculate the gradient value grade in S12, S22, or S42, and when shifting is in progress, it is preferable to proceed to step S52 to use the previous value before the start of shifting without calculating the gradient value grade. By doing so, it is avoided that the gradient value becomes an abnormal value due to instability of the turbine rotational speed TREV, and the accuracy of the shift control is ensured. In this case, since the shift is completed in a very short time, even if the previous gradient value grade is used in this way, the difference from the actual gradient is small, and the accuracy of the shift control is sufficiently secured. In step S52, instead of using the previous gradient value grade, the gradient value grade may be calculated using various signals before the start of shifting.
[0061]
【The invention's effect】
  As described above, according to the automatic transmission control device of the present invention, when the vehicle is traveling uphill,When the slope of the uphill road is larger than the first predetermined value, a shift line on the lower vehicle speed side than when traveling on a flat road is used as a shift line for downshifting in the shift map,Since downshifting is unlikely to occur, even if the driver depresses the accelerator pedal so that the vehicle speed does not decrease with respect to the ascending slope, or if the driver performs the accelerator operation unconsciously, Unnecessary to the driverDownshiftOccurrence of shifting is suppressed, and driving comfort and quietness that meet the needs of the driver can be obtained.
[0071]
  AndIn a state where the slope of the uphill road is larger than the second predetermined value which is larger than the first predetermined value.When a downshift occurs, as a shift up shift line,From running on a flat roadSince the shift line on the high vehicle speed side is used, this makes it more difficult to shift up from the shift stage after the downshift to the original shift stage before the downshift.
[0072]
  In other words, when driving uphill, first of all, unnecessary unnecessary driver's intention.DownshiftA shift down regulation is performed to suppress the occurrence of a shift, but if there is an accelerator pedal depression operation intended to accelerate beyond this shift down regulation,The present inventionThis time, instead, the shift-up shift line when the above-mentioned shift-down restriction is not operating, in other words, the shift line on the higher vehicle speed side than the shift-up shift line when traveling on a flat road is used. As a result, the upshift regulation becomes more strict and the upshift is less likely to occur than when traveling on a flat road. In other words, this is the same control as conventional climbing control, in other words,The present inventionFirst of all, when driving uphill, it is unnecessary and unnecessary for the driver.DownshiftWhile suppressing the occurrence of shifting, it is necessaryif there isThus, the shift to the uphill control similar to the conventional one is made so that a larger driving force is given. As a result, when the driver is operating the accelerator to such an extent that the vehicle speed is not reduced with respect to the ascending slope, driving with the current gear stage is achieved, and driving and quietness can be obtained. When the accelerator pedal is depressed further in the hope of acceleration, the control shifts to climbing control, and driving at low gears and increase in driving force over a long period of time are achieved, thereby satisfying the driver's needs, and more A more precise two-stage shift control is realized.
[Brief description of the drawings]
FIG. 1 is a vehicle control system diagram according to an embodiment of the present invention.
FIG. 2 is a flowchart of first shift control in the vehicle.
FIG. 3 is a conceptual diagram of a shift map used when traveling on a flat road with the same shift control.
FIG. 4 is a conceptual diagram of a shift map used during uphill traveling under the same shift control.
FIG. 5 is a conceptual diagram of another shift map used during uphill traveling under the same shift control.
FIG. 6 is a flowchart of the first half of second shift control in the vehicle.
FIG. 7 is a flowchart of the second half of the second shift control.
[Fig. 8]Examples of shift control related to the present inventionFIG.
FIG. 9 is a flowchart illustrating an improved calculation of a gradient value in each of the shift controls.
FIG. 10 is an explanatory diagram of a problem to be solved by the present invention.
FIG. 11 is also an explanatory diagram of a problem to be solved by the present invention.
[Explanation of symbols]
5 Engine
6 Torque converter
7 Transmission gear mechanism
8 Automatic transmission
20 Control unit

Claims (3)

A control device for an automatic transmission that automatically switches a gear position based on a driving state of a vehicle and a shift map, a gradient detecting unit that detects a gradient of an uphill road when the vehicle is traveling uphill, and detected by the detection unit When the slope of the uphill road is larger than a first predetermined value, a shift down that makes it difficult for the downshift to occur by using a shift line on the lower vehicle speed side than when traveling on a flat road as a downshift line in the shift map. When a downshift occurs when the slope of the uphill road detected by the restricting means and the detecting means is greater than a second predetermined value that is greater than the first predetermined value, the shift upshift line in the shift map is flat. by than during road travel using the shift line at a higher vehicle speed side, the self characterized in that the shift-up restricting means for hard to occur the shift-up is provided Control device for a transmission. The shift-down restricting means corrects the shift-down shift line in the shift map to the low vehicle speed side when it is detected that the slope of the uphill road is larger than the first predetermined value. The shift-up restricting means uses a shift-up shift line in the shift map when a downshift occurs when the slope of the uphill road is larger than a second predetermined value. 2. The control device for an automatic transmission according to claim 1 , wherein a shift line on a higher vehicle speed side than when traveling on a flat road is used as the shift-up shift line by correcting to a higher vehicle speed side . The shift-down restricting means has a shift map in which the shift-down shift line is set at a lower vehicle speed side than the shift map for the flat road when it is detected that the slope of the uphill road is larger than the first predetermined value. By switching to, a shift line on the lower vehicle speed side than when traveling on a flat road is used as the shift line for downshifting, and the upshift restricting means has caused downshifting when the slope of the uphill road is larger than the second predetermined value. Sometimes, the shift map is switched to a shift map in which the shift-up shift line is set on the higher vehicle speed side than the flat road shift map, so that the shift-up shift line is a shift line on the higher vehicle speed side than when traveling on a flat road. The control apparatus for an automatic transmission according to claim 1 , wherein:

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