JP2004162800A - Speed change controller of continuously-variable transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a speed change controller of a continuously-variable transmission capable of surely giving driving feeling in response to an acceleration intention of a driver during kickdown acceleration in spite of running resistance such as hauling works. <P>SOLUTION: The speed change controller comprises a controller 1 controlling speed change ratios of the continuously-variable transmission 10 based on a determined speed change ratios in response to vehicle speed VSP and the control input APO of an accelerator, an acceleration speed change characteristic determining means deciding magnitude of an acceleration request and determining respectively speed change characteristics for a down-shift and an up-shift based on the magnitude of an acceleration request. Further, the speed change controller provides an acceleration controlling means executing an up-shift based on the speed change characteristic of an up-shift after executing a down-shift to the speed change ratio controlled more than a speed change ratio determined by a speed change ratio determining means based on the speed change characteristic of a down-shift when the acceleration request is greater than a predetermined standard value. Further, the speed change controller comprises an accelerating slate deciding means deciding slowing down for extension of acceleration after down-shifted, and an up-shift targeted speed changerate compensation means compensating a targeted speed change rate of the up-shift to the down-shift side when the extension of acceleration is slowed down. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a shift control device for a vehicle having a continuously variable transmission.
[0002]
[Prior art]
In the shift control of a conventional continuously variable transmission, a shift pattern corresponding to a vehicle speed and an accelerator operation amount is stored as a map of a target input shaft speed, and a target speed ratio is determined from the target input shaft speed according to a driving state. (See JP-A-4-54371).
[0003]
In this conventional example, even if a kick-down operation for rapidly increasing the accelerator operation amount with the intention of rapid acceleration is performed from a steady running state in which the vehicle travels at a substantially constant vehicle speed with a relatively small accelerator operation amount, the accelerator operation amount at this time is reduced. Since it takes some time for the actual gear ratio to reach the corresponding target gear ratio, the driving force does not increase despite the engine speed rising immediately, and during that time, the engine seems to be blowing. It gives a strange feeling to the driver.
[0004]
As a countermeasure against this, it is conceivable to suppress a change in the gear ratio when the acceleration demand is large. For example, a method has been proposed in which the gear ratio is fixed to a constant value when the throttle opening exceeds a threshold value (Japanese Patent No. 25933432). etc). This means that the method of determining the constant speed ratio is the speed ratio on the speed change map when the throttle opening is a threshold value. As described above, by fixing the gear ratio before the gear ratio becomes large, an increase in engine rotation quickly increases the driving force, so that a time delay from the increase in the throttle to the feeling of acceleration is reduced. Accordingly, the uncomfortable feeling is reduced and the acceleration responsiveness on the bodily sensation is improved.
[0005]
[Patent Document 1]
JP-A-4-54371 [Patent Document 2]
Patent No. 2593432 [0006]
[Problems to be solved by the invention]
On the other hand, however, in such a method of determining the constant speed ratio, the constant speed ratio is maintained as long as the throttle opening is not returned from the threshold value and the hysteresis setting, thereby satisfying the driver's initial acceleration intention. Since the change in the gear ratio does not occur even after the start, this leads to a feeling of strangeness. In other words, in order to generate a change in the gear ratio, an operation of intentionally returning the accelerator pedal to a large value is required.
[0007]
Therefore, the present invention has been made in view of the above problems, and it is an object of the present invention to reliably provide a vehicle speed increase according to the driver's acceleration intention during kickdown acceleration regardless of an increase in running resistance due to traction or the like. I do.
[0008]
[Means for Solving the Problems]
According to a first aspect of the present invention, there is provided a driving state detecting unit that detects a driving state of a vehicle including a vehicle speed and an accelerator operation amount, a gear ratio determining unit that determines a gear ratio according to the vehicle speed and an accelerator operation amount, Control means for controlling the speed ratio of the continuously variable transmission based on the speed ratio.
Acceleration request determining means for determining the magnitude of the acceleration request; acceleration shift characteristic determining means for respectively determining a downshift shift characteristic and an upshift shift characteristic based on the magnitude of the acceleration request; When it is larger than a preset reference value, after performing a downshift to a downshift target gear ratio suppressed from a target gear ratio determined by the gear ratio determining means based on the downshift gear characteristics, the upshift gearshift is performed. Acceleration control means for performing an upshift with an upshift target gear ratio based on characteristics; acceleration state determination means for determining an acceleration state after a downshift by the acceleration control means; and if the acceleration state is equal to or less than a preset value, An upshift target gear ratio correction means for correcting the upshift target gear ratio to the downshift side in accordance with the acceleration state. Provided with a door.
[0009]
In a second aspect based on the first aspect, the acceleration state determining means calculates a driving force by detecting or estimating an output torque of the engine, and a driving force calculating means for calculating the driving force. A look-ahead vehicle speed calculating means for calculating, as a look-ahead vehicle speed, a vehicle speed achievable with the current driving force from the set running resistance, and a determination based on a difference between the look-ahead vehicle speed and the current vehicle speed.
[0010]
In a third aspect based on the second aspect, the upshift target speed ratio correction means corrects the upshift target speed ratio toward the downshift side as the difference between the pre-read vehicle speed and the current vehicle speed increases.
[0011]
In a fourth aspect based on any one of the first to third aspects, the acceleration shift characteristic determining means includes a plurality of downshift shift characteristics preset in accordance with the magnitude of an acceleration request. One is selected and one is selected from a plurality of upshift characteristics set in advance according to the magnitude of the acceleration request.
[0012]
In a fifth aspect based on the fourth aspect, the upshift speed change characteristic sets a shift amount at which the speed ratio is shifted from the speed ratio after the downshift to a lower speed ratio in accordance with an increase in the vehicle speed.
[0013]
In a sixth aspect based on the fifth aspect, the upshift speed change characteristic sets a smaller shift amount for shifting to a lower gear ratio in accordance with an increase in the vehicle speed, as the acceleration request increases.
[0014]
In a seventh aspect based on any one of the first to sixth aspects, the acceleration request determining means detects an accelerator operation speed based on an accelerator operation amount, and determines the accelerator operation speed and the accelerator operation speed. The magnitude of the acceleration request is determined based on the amount.
[0015]
In an eighth aspect based on any one of the first to seventh aspects, the acceleration control means changes a reference value for comparing the acceleration request in accordance with a vehicle speed and an accelerator operation amount.
[0016]
【The invention's effect】
Therefore, according to the first invention, when the acceleration demand is large (for example, during kickdown acceleration), the downshift is performed at the downshift target speed ratio having the downshift speed characteristic that is more suppressed than the normal speed determined by the speed ratio determining means. After performing the shift, by performing an upshift to the lower side of the gear ratio at the upshift target gear ratio based on the upshift gear characteristic, it is possible to suppress an excessive increase in the engine speed and a decrease in vehicle acceleration during acceleration. By balancing the rise and fall of the vehicle acceleration, it is possible to reliably obtain the vehicle acceleration according to the driver's intention to accelerate, and when the acceleration growth slows down after the downshift, the target gear ratio for the upshift is reduced to the acceleration slowdown. Correction to the downshift side in accordance with it, so even when running resistance such as towing or climbing a slope increases, a feeling of acceleration consistent with the intention of acceleration is always obtained. Bets can be, at the driveability of a vehicle equipped with a continuously variable transmission can be greatly improved.
[0017]
Further, the second invention determines the acceleration state from the difference between the look-ahead vehicle speed achievable with the current driving force and the actual vehicle speed, so that the vehicle speed does not increase despite the large accelerator operation amount. Can be determined quickly and accurately.
[0018]
Further, in the third invention, in the upshift after the downshift, the upshift target speed ratio is corrected toward the downshift side as the difference between the pre-read vehicle speed and the current vehicle speed increases, so that the speed change is performed so that the vehicle speed slowdown is reduced. To maintain acceleration.
[0019]
According to the fourth aspect of the present invention, since the speed change characteristic for acceleration selects one from each of a plurality of downshift speed characteristics and a plurality of upshift speed characteristics, regardless of a change in the driving state, the acceleration intention of the driver is selected. Can be achieved.
[0020]
According to the fifth aspect of the present invention, in the upshift speed change characteristic, the shift amount is set to a smaller side of the speed ratio from the speed ratio after the downshift in accordance with the increase of the vehicle speed. Can be suppressed, and the acceleration can be increased.
[0021]
According to the sixth aspect of the present invention, the larger the request for acceleration, the smaller the shift amount for shifting to a smaller gear ratio in accordance with the increase in vehicle speed. Therefore, the engine speed is increased in accordance with the magnitude of the acceleration intention. Thus, it is possible to obtain the vehicle acceleration according to the driver's expectation.
[0022]
In the seventh aspect, the magnitude of the acceleration request is determined based on the accelerator operation speed and the accelerator operation amount, so that the driver's acceleration intention can be accurately determined.
[0023]
Further, in the eighth invention, the reference value for comparing the acceleration request is changed according to the vehicle speed and the accelerator operation amount, so that the downshift can be performed according to the driver's acceleration intention regardless of the change in the driving state. it can.
[0024]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.
[0025]
FIG. 1 shows a schematic configuration of a vehicle to which the present invention is applied, in which an engine 11 is connected to a continuously variable transmission 10 having a torque converter 12 so that an optimal driving state is obtained according to a driving state. The controller 1 controls the output of the transmission 11 and the gear ratio of the continuously variable transmission 10. The continuously variable transmission mechanism of the continuously variable transmission 10 may be a V-belt type or a toroidal type.
[0026]
The controller 1 performs fuel injection amount control, ignition timing control, and the like of the engine 11 according to the operation state, and controls the speed ratio steplessly according to the operation state. The controller 1 is an integrated control device having both engine control means and shift control means.
[0027]
The controller 1 includes an accelerator sensor 5 for detecting an accelerator pedal operation amount APO (or an accelerator operation amount), a vehicle speed sensor 4 for detecting a running speed of a vehicle (hereinafter, a vehicle speed VSP), and an engine rotation for detecting a rotation speed Ne of the engine 11. A sensor 2, an input shaft rotation sensor 3 for detecting an input shaft rotation speed Nt of the continuously variable transmission 10 and the like are connected, and detect as a driving state of the vehicle. Here, the vehicle speed sensor 4 detects the output shaft rotation speed OutRev of the continuously variable transmission 10 and multiplies it by a final reduction ratio or a constant (such as a tire radius) according to the vehicle specification to obtain a vehicle speed VSP. And
[0028]
FIG. 2 is a flowchart showing an example of the shift control according to the present invention, which is executed periodically (for example, every several tens of msec) by the microcomputer of the controller 1.
[0029]
In this control, a change in the gear ratio is suppressed when a predetermined acceleration condition (kickdown acceleration) is satisfied from a control mode in which the gear ratio is variably controlled in accordance with the operation state (hereinafter, referred to as “normal mode”). The control mode is shifted to a control mode (hereinafter referred to as a "linear mode"), and when the detected vehicle speed elongates slowly during re-acceleration such as kick-down acceleration, the mode is switched to the linear mode when the running resistance increases. .
[0030]
Although not explicitly shown in the figure, detection processing of the accelerator operation amount APO and the vehicle speed VSP is performed as an operating state in the background of these routines. Further, in the following description, the numbers indicated by the reference symbols S correspond to the processing steps in FIG.
[0031]
First, in step S1, it is determined whether the previous control mode is the normal mode or the linear mode with reference to the control flag F. If the previous control mode is the normal mode, the kick down in step S2 is performed. On the other hand, if the previous control mode is the linear mode, the process proceeds to step S4 to determine whether or not the condition for releasing the linear mode is satisfied. The control flag F indicates, for example, a linear mode when it is 1, and a normal mode when it is 0.
[0032]
In step S2, it is determined whether or not a kick down operation has been performed. First, an accelerator operation speed dAPO is obtained from a difference between the detected accelerator operation amount APO and the previous value of the accelerator operation amount APO.
[0033]
Then, from the map shown in FIG. 3, a reference value dAPOL which is a threshold value of the accelerator operation speed is obtained from the current vehicle speed VSP and the accelerator operation amount APO, and if the accelerator operation speed dAPO exceeds the reference value dAPOL, the kick is determined. It is determined that the operation is the down operation, and the process proceeds to step S3. If the accelerator operation is other than the kick down operation, the process proceeds to step S30 to control the normal mode.
[0034]
Note that the map of the accelerator operation amount APO and the reference value dAPOL of the accelerator operation speed according to the vehicle speed VSP in FIG. 3 divides the accelerator operation amount APO into a plurality of ranges, and divides the vehicle speed VSP into a plurality of ranges. The reference value dAPOL is set for each of the range of the accelerator operation amount APO and the range of the vehicle speed VSP.
[0035]
Next, in step S3 where it is determined that the kick-down operation has been performed, the control flag F is set to 1, and then the process proceeds to step S5 to determine the driver's intention to accelerate (acceleration request).
[0036]
In step S5, based on the accelerator operation speed dAPO and the accelerator operation amount APO obtained in step S2, an acceleration intention is searched from the map of FIG. In this map, when the accelerator operation amount APO is large, it is determined that the acceleration intention is large irrespective of the accelerator operation speed dAPO, and the accelerator operation amount APO is in the middle region (for example, APO is 3/8 to 6 / In 5), if the accelerator operation speed dAPO is high, the intention to accelerate is determined to be medium, and if the accelerator operation speed dAPO is low, the intention to accelerate is determined to be low. A predetermined hysteresis is provided for the acceleration intention that changes according to the magnitude of the accelerator operation amount APO, thereby preventing control hunting.
[0037]
Next, in step S6, it is determined with reference to the mode flag Mf whether or not to switch between the downshift mode and the upshift mode in the linear mode.
[0038]
When the mode flag Mf is 0, it is determined that there is a mode shift because the switching from the downshift mode to the upshift mode has not been completed, and when the mode flag Mf = 1, the mode is switched from the downshift mode to the upshift mode. Since the shift to the upshift mode has been completed, it is determined that there is no mode shift. If there is a mode transition, the process proceeds to step S7, whereas if there is no mode transition, the process proceeds to step S19.
[0039]
In step S7, it is determined whether the mode is the downshift mode or the upshift mode.
[0040]
Here, the downshift speed ratio DW_ratio (0) is not set, or the actual speed ratio (input shaft rotation speed impRev / output shaft rotation speed OutRev) has reached the downshift speed ratio DW_ratio (0). If not, it is determined that the mode is the downshift mode, and the process proceeds to step S8.
[0041]
On the other hand, if the actual gear ratio has reached the downshift amount DW_ratio (0), it is determined that the upshift mode has been set, and 1 is added to the mode flag Mf, and then the process proceeds to step S10.
[0042]
In step S8 of the downshift mode, a downshift shift characteristic according to the acceleration intention is selected from the map of FIG. 5 based on the acceleration intention determined in step S5.
[0043]
Then, in step S9, according to the current vehicle speed VSP, the downshift speed ratio DW_ratio (0) is obtained from the speed change characteristics selected in step S8 and stored.
[0044]
Thereafter, the process proceeds to step S16, and the target speed ratio Dratio is calculated from the following equation.
[0045]
Ratio = DW_ratio (0) −UP_ratio (0) + UP_ratio (n) (1)
Here, UP_ratio (0) is an initial value of the upshift amount, and UP_ratio (n) is a correction amount of the upshift amount (shift amount to a smaller gear ratio) according to an increase in vehicle speed.
[0046]
When the process proceeds from step S9 to step S16, the upshift amount initial value UP_ratio (0) and the upshift amount UP_ratio (n) are both 0, and the target speed ratio Dratio = DW_ratio (0).
[0047]
Next, in step S17, the target input shaft rotation speed DsrRev is
DsrRev = Dratio × OutRev (2)
The process proceeds to step S18 to output the target speed ratio Dratio, and controls the speed ratio of the continuously variable transmission 10.
[0048]
On the other hand, in step S10 in which the upshift mode is determined in the determination in step S7, the pre-read vehicle speed tVSP is obtained from the driving force and the vehicle speed VSP, and the difference between the current vehicle speed VSP and the pre-read vehicle speed tVSP is equal to or more than a predetermined value. It is determined whether or not the increase in the actual vehicle speed VSP is not slowed down with respect to the accelerator operation amount APO based on whether or not the vehicle speed VSP is normal. (Linear mode when running resistance increases).
[0049]
In determining the pre-read vehicle speed tVSP, first, the output torque of the engine 11 is determined.
[0050]
The engine output torque is calculated from the fuel injection pulse width (fuel injection amount) calculated by the engine control unit of the controller 1 and the detected engine rotation speed Ne, or when the characteristic diagram of the engine 11 is provided, The engine output torque is estimated from the accelerator operation amount APO and the engine rotation speed Ne.
[0051]
Then, a driving force is calculated from the engine output torque by the following equation.
[0052]
Driving force = engine output torque x total reduction ratio / tire radius ... (3)
However, the total reduction ratio is the sum of the current actual transmission ratio and the reduction ratio of a differential gear or the like.
[0053]
When a lock-up clutch (not shown) of the torque converter 12 is in a released state, the engine output torque is corrected based on a predetermined torque ratio.
[0054]
Then, as shown in FIG. 7, a driving force for maintaining the current vehicle speed on a flat road is calculated from a preset running resistance map (corresponding to a flat road), and the difference between the driving force and the driving force obtained by the above equation (3) is calculated. Is divided by the vehicle speed to calculate the acceleration obtained by the vehicle, and the integrated vehicle acceleration is added to the current vehicle speed to obtain a achievable vehicle speed as the look-ahead vehicle speed tVSP.
[0055]
Next, the current vehicle speed VSP (actual vehicle speed) and the look-ahead vehicle speed tVSP are
Look-ahead vehicle speed tVSP-actual vehicle speed VSP> predetermined value ... (4)
If the vehicle speed VSP due to the current driving force is lower than the predetermined vehicle speed tVSP by more than a predetermined value, it is determined that the acceleration is slow, and the process proceeds to the upshift mode when the running resistance increases in step S11. On the other hand, if the difference between the pre-read vehicle speed tVSP and the actual vehicle speed VSP is within a predetermined value, it is determined that acceleration according to the driving force has been realized, and the normal upshift mode processing of step S14 is performed.
[0056]
In order to determine the acceleration, the acceleration obtained from the driving force may be estimated and compared with the actual acceleration.However, since the estimated acceleration greatly changes by operating the accelerator, here, by converting to the pre-read vehicle speed, Thus, it is possible to reliably determine the acceleration slowdown with less erroneous determination.
[0057]
The predetermined value of the above equation (4) is determined by the setting items of the vehicle type and the vehicle characteristics. The lower the vehicle speed, the slower the acceleration becomes. For example, when the vehicle speed is 20 km / h, the predetermined value is 5 km / h, and when the vehicle speed is 80 km / h or more, the predetermined value is 15 km / h. A predetermined value at each vehicle speed is obtained.
[0058]
As the vehicle weight, for example, a value obtained by adding the weight of the vehicle body and two occupants is used. Although the weight of the vehicle body slightly changes due to a change in the number of occupants or the like, it is usually within 10% of the total weight, which is smaller than the increase or decrease in the running resistance when traveling on an uphill road or when towing.
[0059]
In the upshift mode during running resistance increase in step S11, the shift characteristic of the upshift corresponding to the acceleration intention is selected from the map in FIG. 6 based on the acceleration intention determined in step S5.
[0060]
Next, in step S12, the vehicle speed deviation eVSP is defined as the vehicle speed deviation eVSP, and the gear ratio correction amount ΔDawn corresponding to the vehicle speed deviation eVSP is used as the correction amount for the increase in the running resistance. (Downshift amount).
[0061]
In step S13, an upshift amount initial value UP_ratio (0) is obtained from the upshift speed characteristic selected in step S11 according to the current vehicle speed VSP, and the speed ratio corresponding to the running resistance increase obtained in step S12 is obtained. From the correction amount ΔDawn,
UP_ratio (0) = UP_ratio (0) −ΔDawn (5)
Thereby corrects the upshift amount initial value UP_ratio (0) to the downshift side.
[0062]
Then, the process proceeds to step S16, where the target speed ratio Dratio is calculated from the above equation (1). After the target speed ratio Dratio is obtained in step S17, the target speed ratio Dratio is output in step S18.
[0063]
Accordingly, in the upshift mode at the time of increasing the running resistance, the upshift amount of the initial upshift amount UP_ratio (0) is suppressed by the downshift-side speed ratio correction amount ΔDawn compared to the normal upshift mode. Alternatively, when the increase in the vehicle speed VSP is extremely low due to the downshift (when the vehicle speed deviation e is extremely large), a further downshifted value is set and an instruction to increase the driving force is issued.
[0064]
When the process proceeds from step S13 to step S16, the upshift amount UP_ratio (n) is not calculated because it has not been calculated, and the target gear ratio Dratio = DW_ratio (0) -UP_ratio (0).
[0065]
On the other hand, in step S14 in which the normal upshift mode is determined in step S10, the shift characteristic of the upshift corresponding to the acceleration intention is selected from the map of FIG. 6 based on the acceleration intention determined in step S5. I do.
[0066]
Next, in step S15, an upshift amount initial value UP_ratio (0) is obtained from the upshift speed characteristic selected in step S11 and stored according to the current vehicle speed VSP.
[0067]
Then, the process proceeds to step S16, where the target speed ratio Dratio is calculated from the above equation (1). After the target speed ratio Dratio is obtained in step S17, the target speed ratio Dratio is output in step S18.
[0068]
However, when the process proceeds from step S15 to step S16, the upshift amount UP_ratio (n) is 0, and the target speed ratio Dratio = DW_ratio (0) −UP_ratio (0).
[0069]
In this way, in the first control cycle of the upshift mode in which the downshift has been completed, in the steps S10 to S15, the normal upshift mode and the upshift when the running resistance increases according to the magnitude of the deviation eVSP between the pre-read vehicle speed tVSP and the actual vehicle speed VSP. One of the modes is selected, and when the running resistance increases, the downshift-side speed ratio correction amount ΔDawn suppresses the upshift amount from the normal upshift mode.
[0070]
Next, in step S19, in which it is determined in step S6 that there is no mode shift, the pre-read vehicle speed tVSP is obtained from the driving force in the same manner as in step S10, and the magnitude of the vehicle speed deviation e, which is the difference from the actual vehicle speed VSP, is obtained. It is determined whether the mode is the normal upshift mode or the running resistance increase upshift mode based on.
[0071]
If the vehicle speed deviation eVSP exceeds a predetermined value, the vehicle speed is insufficiently increased. Therefore, it is determined that the upshift mode is set when the running resistance increases, and the process proceeds to step S20. If the vehicle speed deviation e is within the predetermined value, the accelerator operation amount APO Since the acceleration force (increase of the vehicle speed VSP) according to the above is achieved, the normal upshift mode is determined, and the process proceeds to step S23.
[0072]
First, in step S20, which is the upshift mode when the running resistance increases, the shift characteristic of the upshift according to the acceleration intention is selected from the map of FIG. 6 based on the acceleration intention determined in step S5.
[0073]
In step S21, the gear ratio correction amount ΔDawn is obtained from the map of FIG. 8 based on the vehicle speed deviation e.
[0074]
Next, in step S22, the upshift amount UP_ratio (n) corresponding to the increase in the vehicle speed is obtained from the upshift speed change characteristic selected in step S20 according to the current vehicle speed VSP, and then obtained in step S21. With the gear ratio correction amount ΔDawn, the upshift amount UP_ratio (n) is
UP_ratio (n) = UP_ratio (n) −ΔDawn (6)
To correct.
[0075]
Then, the process proceeds to step S16 to calculate the target speed ratio Dratio from the above equation (1), and outputs the target speed ratio Dratio in steps S17 and S18.
[0076]
On the other hand, in step S23 where it is determined in the above-described step S19 that the normal upshift mode has been set, the shift characteristic of the upshift according to the acceleration intention is determined from the map of FIG. 6 based on the acceleration intention determined in step S5. select.
[0077]
Then, in step S24, the upshift amount UP_ratio (n) corresponding to the increase in the vehicle speed is obtained from the upshift speed change characteristic selected in step S23 according to the current vehicle speed VSP, and this upshift amount UP_ratio (n) will be obtained from the next time on. ) Is updated, the process proceeds to step S16, the target speed ratio Dratio is calculated from the above equation (1), and the target speed ratio Dratio is output in steps S17 and S18.
[0078]
Next, in step S4, which proceeds when the previous control mode was the linear mode in step S1, the accelerator operation amount APO is returned to a predetermined value such as 0/8 or the like after the linear mode is set, and If a predetermined time has elapsed since the shift to the linear mode, the linear mode is canceled and the process proceeds to step S30 to control the normal mode. When releasing the linear mode, the control flag F, the mode flag Mf, the downshift speed ratio DW_ratio (0), the upshift amount initial value UP_ratio (0), the upshift amount UP_ratio (n), the speed ratio correction amount ΔDawn is reset to 0, respectively.
[0079]
In the control in the normal mode, the target input shaft rotation speed DsrRev is obtained from the current vehicle speed VSP and the accelerator operation amount APO based on the shift map shown in FIG. After that, the output is made in step S17.
[0080]
On the other hand, if the accelerator operation amount APO is equal to or greater than the predetermined value, the driver determines that the driver intends to continue acceleration, and proceeds to step S5 to continue the control in the linear mode.
[0081]
When the kick down operation is determined based on the accelerator operation speed dAPO by the above control, after the downshift is performed with the downshift speed change characteristic according to the acceleration intention, the look-ahead vehicle speed tVSP achievable with the current driving force is performed. One of the upshift mode at the time of running resistance increase and the upshift mode at the normal time is selected according to the magnitude of the deviation eVSP between the vehicle speed VSP and the actual vehicle speed VSP. The upshift is performed, and in the upshift mode when the running resistance increases, the gear ratio correction amount ΔDawn is changed according to the magnitude of the vehicle speed deviation e, the upshift amount in the upshift mode is regulated, and the running resistance increase This compensates for the slowdown in acceleration.
[0082]
The operation of the control depending on the difference in the running resistance will be described below.
[0083]
<A. Normal kick-down operation>
When the accelerator operation speed dAPO exceeds the reference value dAPOL shown in FIG. 3 by depressing the accelerator while traveling on a flat road or a downhill road in the normal mode, normal kick-down acceleration control is started, and the mode shifts to the linear mode. Is determined from the map.
[0084]
First, in the first control, since the mode flag Mf = 0, the downshift speed ratio DW_ratio (0) is set in steps S9 and S10.
[0085]
Here, as shown in FIG. 5, the downshift speed ratio DW_ratio (0) is set to the downshift speed ratio DW_ratio (0) for each vehicle speed, and has different speed characteristics depending on the magnitude of the acceleration intention. It is set so that the downshift amount (the shift amount of the gear ratio to the larger side) increases as the intention of acceleration increases.
[0086]
Then, as shown in FIG. 10, the downshift speed ratio DW_ratio (0) at the time of the kick-down operation is set as the target speed ratio Dratio.
[0087]
Next, when the actual gear ratio reaches the downshift gear ratio DW_ratio (0) = the target gear ratio Dratio, the actual vehicle speed VSP at this time is compared with the look-ahead vehicle speed tVSP achievable with the current driving force. If the deviation eVSP between the speed VSP and the pre-read vehicle speed tVSP is equal to or less than a predetermined value, the normal upshift mode is selected, and as shown by the broken line in FIG. 11, the upshift upon completion of the downshift corresponding to the vehicle speed VSP during the down operation. The quantity initial value UP_ratio (0) is set, and the mode shifts to the normal upshift mode.
[0088]
Here, as the upshift amount initial value UP_ratio (0), as shown in FIG. 6, the upshift amount is set for each vehicle speed, and different shift characteristics are set according to the magnitude of the acceleration intention. The upshift amount according to the vehicle speed is set to be smaller as the intention is larger, and from the above equation (1), the shift to a smaller (Hi) side of the gear ratio is started according to the upshift amount.
[0089]
Until the linear mode release condition is satisfied, the upshift amount UP_ratio (n) is updated in accordance with the increase in the vehicle speed VSP in each control cycle.
[0090]
Therefore, as shown in FIG. 12, in the downshift mode after the kick down operation, the downshift amount is regulated in accordance with the shift characteristics in the map of FIG. 5 as compared with the shift characteristics in the normal mode in FIG. Accordingly, the input shaft rotation speed impRev from the point A to the point B in the drawing is suppressed to improve the height of the vehicle acceleration and the responsiveness of the vehicle acceleration at the initial stage of acceleration.
[0091]
After the downshift gear ratio DW_ratio (0), which is the downshift target gear ratio, is reached, the upshift amount initial value UP_ratio (0) is set based on the upshift gear characteristics shown in FIG. 6 and the vehicle speed VSP according to the acceleration intention. The value obtained by subtracting the upshift amount initial value UP_ratio (0) from the downshift speed ratio DW_ratio (0) becomes the target speed ratio. In FIG. 12, after the point B, as indicated by the solid line in FIG. As described above, the gear ratio is gradually changed to the small side, and an excessive increase in engine speed Ne during acceleration and a decrease in vehicle acceleration can be suppressed, and a vehicle acceleration according to the driver's acceleration intention can be obtained. It is.
[0092]
In FIG. 12, the dashed line in FIG. 12 is based on the conventional example (Japanese Patent Application No. 2001-182803). According to this conventional example, the downshift amount is larger than the point B of the present invention, and the shift to the smaller side is performed thereafter. Is larger than the present invention.
[0093]
For this reason, as shown in FIG. 13, in the linear mode of the present application indicated by a one-dot chain line or a solid line in the figure, the arrival time to the maximum value of the vehicle acceleration is faster than in the conventional example indicated by the dashed line in the figure. The engine rotation speed Ne is suppressed lower than in the conventional example. For this reason, the magnitude of the vehicle acceleration and the arrival time to the maximum acceleration can be set optimally. Further, in the upshift mode, the reduction of the gear ratio is suppressed as compared with the conventional example, so that the increase in the engine rotation speed Ne is ensured. As a result, a decrease in vehicle acceleration can be suppressed, and the acceleration can be felt.
[0094]
At the time of the kick down operation, the shift characteristics according to the driver's intention to accelerate are set on the downshift side and the upshift side based on the plurality of shift characteristics. The degree of freedom in setting the rotation speed Ne can be obtained. In particular, by setting a plurality of shift characteristics according to the intention of acceleration, the calculation load on the controller 1 can be reduced, and the rise and fall of the vehicle acceleration can be balanced. , And good kickdown acceleration can be realized in a wide speed range.
[0095]
Further, in the upshift mode after the downshift, as shown in FIG. 6, the upshift amount corresponding to the vehicle speed is set to be smaller as the acceleration intention is larger, so that the engine rotation speed is set in accordance with the magnitude of the acceleration intention. By increasing the vehicle speed, it is possible to obtain the vehicle acceleration according to the driver's expectation.
[0096]
<B. Kick-down operation when running resistance increases>
Next, when the accelerator operation speed dAPO exceeds the reference value dAPOL shown in FIG. 3 when the accelerator is depressed in the normal mode in which the running resistance is large, such as during towing another vehicle or on an uphill road, it is determined that the kick-down operation is performed. After the acceleration intention is determined, the mode shifts to the linear mode as described above.
[0097]
Here, the downshift speed ratio DW_ratio (0) is the same as described above, and as shown in FIG. 5, the downshift amount (the amount of shift toward a larger speed ratio) increases as the intention of acceleration increases. Is set based on the shift characteristics set in.
[0098]
When the downshift is completed, if the vehicle speed deviation eVSP between the actual vehicle speed VSP and the look-ahead vehicle speed tVSP exceeds a predetermined value, the upshift mode at the time of increasing running resistance is selected, and the gear ratio is set according to the magnitude of the vehicle speed deviation e. The correction amount ΔDawn is set.
[0099]
By the speed ratio correction amount ΔDawn, the upshift amount is restricted to the downshift side (larger speed ratio) than in the normal upshift mode, and when the vehicle speed deviation eVSP is relatively small, the characteristic shown in FIG. As shown in A, the upshift is performed gradually, but when the vehicle speed deviation eVSP is large, the upshift amount = 0 as shown by the characteristic B in the figure, and the vehicle shifts at the downshift speed ratio DW_ratio (0). When the acceleration is continued and the vehicle speed deviation eVSP is extremely large (for example, when the vehicle speed VSP decreases), the upshift amount is reversed to the negative (downshift side) and the downshift is performed as shown by the characteristic C in the figure. The vehicle is accelerated by further downshifting from the shift gear ratio DW_ratio (0).
[0100]
Thus, at the time of the kick down operation, after downshifting is performed with the downshift amount according to the driver's intention to accelerate, in the upshift mode, the magnitude of the running resistance is detected by the increase of the vehicle speed VSP, and the vehicle speed deviation e decreases. Since the upshift amount is corrected as described above, regardless of the magnitude of the running resistance, acceleration response and acceleration elongation can be realized, and an acceleration feeling according to the driver's intention to accelerate can be realized.
[0101]
For example, as shown in FIG. 13, the peak of the vehicle acceleration (front and rear G in the figure) is larger in the linear mode when the running resistance is increased as indicated by the solid line in FIG. However, the acceleration peak occurs earlier than in the conventional example indicated by the broken line in the figure, and the response at the start of acceleration can be ensured in the same manner as in the normal linear mode. In the subsequent upshift, the linear mode at the time of increasing the running resistance is also suppressed in the same manner as the normal mode at the time of acceleration, as in the conventional example indicated by the broken line in FIG. You can achieve elongation.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a continuously variable transmission according to an embodiment of the present invention.
FIG. 2 is a flowchart illustrating an example of shift control performed by a controller.
FIG. 3 is a map of a reference value dAPOL of an accelerator operation speed dAPO according to an accelerator operation amount APO and a vehicle speed VSP.
FIG. 4 is a map of an acceleration intention according to an accelerator operation amount APO and an accelerator operation speed dAPO.
FIG. 5 is a map of a downshift speed ratio DW_ratio (0) according to a vehicle speed using an acceleration intention as a parameter.
FIG. 6 is a map of an upshift amount according to a vehicle speed using an acceleration intention as a parameter.
FIG. 7 is a map showing a running resistance corresponding to a flat road according to a vehicle speed.
FIG. 8 is a map of a speed ratio correction amount to a downshift side according to a magnitude of a vehicle speed deviation.
FIG. 9 is a map of a target input shaft rotation speed corresponding to a vehicle speed VSP using an accelerator operation amount APO used in a normal mode as a parameter.
FIG. 10 is a map of the downshift speed ratio according to the vehicle speed VSP, showing how the downshift speed ratio DW_ratio (0) is determined.
FIG. 11 is a map of an upshift amount according to a vehicle speed VSP, showing how an upshift amount is determined.
FIG. 12 is a map of the input shaft rotation speed impRev according to the vehicle speed VSP when the kick-down acceleration is performed. The trajectory of the linear mode when the resistance increases is shown, and the dashed line in the figure shows the trajectory of the rotation speed impRev according to the conventional example.
FIG. 13 is a graph showing the relationship between accelerator operation amount APO, engine rotation speed, vehicle acceleration G (front and rear G) and time when kick-down acceleration is performed. In the figure, the dashed line indicates the normal linear mode, and the dashed line indicates the conventional example.
[Explanation of symbols]
Reference Signs List 1 controller 2 engine rotation sensor 3 input shaft rotation sensor 4 vehicle speed sensor 5 accelerator sensor 10 continuously variable transmission 11 engine

Claims (8)

Driving state detecting means for detecting a driving state of the vehicle including a vehicle speed and an accelerator operation amount;
Speed ratio determining means for determining a speed ratio according to the vehicle speed and the accelerator operation amount,
Control means for controlling the speed ratio of the continuously variable transmission based on the determined speed ratio.
Acceleration request determination means for determining the magnitude of the acceleration request;
Speed-change characteristic determining means for determining the speed-change characteristic of the downshift and the speed-change characteristic of the upshift based on the magnitude of the acceleration request,
When the acceleration request is greater than a preset reference value, after performing a downshift to a downshift target speed ratio that is suppressed from a target speed ratio determined by the speed ratio determining means based on the downshift speed characteristics, Acceleration control means for performing an upshift with an upshift target gear ratio based on the upshift gear characteristic,
Acceleration state determination means for determining an acceleration state after a downshift by the acceleration control means,
When the acceleration state is equal to or less than a preset value, an upshift target gear ratio correction means for correcting the upshift target gear ratio to a downshift side according to the acceleration state,
A shift control device for a continuously variable transmission, comprising: The acceleration state determination unit detects or estimates an output torque of the engine to calculate a driving force, and a vehicle speed achievable with the current driving force from the calculated driving force and a preset traveling resistance. 2. A shift control device for a continuously variable transmission according to claim 1, wherein a pre-reading vehicle speed calculating means for calculating the pre-reading vehicle speed and a difference between the pre-reading vehicle speed and the current vehicle speed. 3. The continuously variable transmission according to claim 2, wherein the upshift target speed ratio correction unit corrects the upshift target speed ratio toward the downshift side as the difference between the pre-read vehicle speed and the current vehicle speed increases. Transmission control device. The acceleration shift characteristic determining means selects one from a plurality of downshift shift characteristics preset according to the magnitude of the acceleration request and a plurality of upshifts preset according to the magnitude of the acceleration request. The shift control device for a continuously variable transmission according to any one of claims 1 to 3, wherein one is selected from shift shift characteristics. The speed change of the continuously variable transmission according to claim 4, wherein the upshift speed change characteristic sets a shift amount that shifts from a speed ratio after the downshift to a lower speed ratio in accordance with an increase in vehicle speed. Control device. 6. The shift control of a continuously variable transmission according to claim 5, wherein the upshift speed change characteristic is set such that a shift amount for shifting to a lower gear ratio in accordance with an increase in vehicle speed decreases as the acceleration request increases. apparatus. 3. The acceleration request determining unit detects an accelerator operation speed based on an accelerator operation amount, and determines a magnitude of an acceleration request based on the accelerator operation speed and the accelerator operation amount. 7. The shift control device for a continuously variable transmission according to any one of 6. 8. The continuously variable transmission according to claim 1, wherein the acceleration control unit changes a reference value for comparing the acceleration request according to a vehicle speed and an accelerator operation amount. Transmission control device.

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