JP2005344773A - Shift controller for vehicular automatic transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To restrain the deterioration in drivability by maximally quickly performing a coast downshift in sudden deceleration while avoiding a shift shock. <P>SOLUTION: In a coast downshift of sudden deceleration, a predicted vehicle speed Vd after downshift by an ordinary single shift is determined (S3). A target gear stage is set on the basis of its predicted vehicle speed Vd (S4). A combination of shift patterns becoming the shortest in the total shift time is selected from a plurality of preset shifty patterns (S5). The coast downshift is performed in order in response to the combination of its selected shift patterns (S6 to S8). In this case, since the shift pattern is set only on a pattern capable of shifting by a series of shift control while preventing the occurrence of a shift shock, the total shift time can be minimized in performing the coast downshift up to the target gear stage while avoiding the shift shock, to restrain the deterioration in drivability caused by lengthening of the shift time. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a shift control device for an automatic transmission for a vehicle, and more particularly to a shift control device that quickly performs a coast-down shift during sudden deceleration.

  (a) an automatic transmission in which a plurality of gear stages having different gear ratios are established by selectively engaging a plurality of friction engagement devices, and (b) the vehicle speed as a parameter when the accelerator is decelerated. 2. Description of the Related Art A shift control device for an automatic transmission for a vehicle is known that includes coast down shift control means that performs a down shift according to a predetermined shift condition. The shift control device described in Patent Document 1 is an example, and when a multi-stage down shift that shifts to two or more lower gears is required during sudden deceleration, the intermediate gear is skipped and the down shift is performed. By performing the jump shift, the shift time is shortened as compared with the case of repeating a single shift in which the down shift is performed one step at a time. Further, in Patent Document 2, when a plurality of downshifts are overlapped in timing, the process shifts to the next shift control from the middle of the first shift control, or immediately after the first shift control ends. It has been proposed to perform multiple shifts for starting shift control.

JP 2000-205386 A JP-A-10-281277

  However, depending on the type of downshift, when a jump shift or multiple shift is performed, the engagement and disengagement timing of the friction engagement device shifts, causing the engine to blow up or torque to be lost, resulting in a shift shock. In addition, there is a case where the shift control (hydraulic control or the like) is delayed accordingly, and the shift time becomes longer and the reacceleration performance is impaired. For example, when shifting by simultaneously engaging a plurality of friction engagement devices, it is difficult to appropriately control the engagement timing, and there is a possibility that the shift shock may occur. Jumping and multiple shifting are limited. The automatic transmission shown in FIGS. 1 and 2 will be described in detail. For example, in the case of 4 → 1 shift, the clutch C0 and the brake B1 need to be released and the clutch C1 and the brake B2 must be engaged. Thus, a shift shock is likely to occur, and such a jump shift is prohibited.

  For this reason, depending on the type of downshift, a single shift is repeated to perform multiple downshifts. However, since the total shift time becomes longer, the reacceleration performance is impaired and drivability deteriorates. Such a problem becomes more prominent as the number of gear stages of the automatic transmission increases.

  The present invention has been made in the background of the above circumstances, and the object of the present invention is to avoid coasting shocks and to perform coast down shifting at the time of sudden deceleration as quickly as possible so that the multi-stage of an automatic transmission can be performed. The purpose is to prevent the drivability from deteriorating due to the increase in the cost.

  In order to achieve such an object, the first invention includes: (a) an automatic transmission in which a plurality of gear stages having different gear ratios are established by selectively engaging a plurality of friction engagement devices; (b) a coast downshift control means for performing a downshift according to a predetermined shift condition with the vehicle speed as a parameter when the accelerator is decelerated, and (c) the downshift At the time, a plurality of shift patterns that can be shifted by a series of shift control are stored in the storage device in advance, (d) the coast down shift control means (d-1) predicts the vehicle speed after the down shift, A target gear stage setting means for setting a target gear stage according to the shift condition based on the predicted vehicle speed, and (d-2) the target gear stage from a plurality of shift patterns stored in the storage device. A shift pattern selecting means for selecting a single shift pattern or a combination of a plurality of shift patterns that minimizes the shift time required for downshifting in (d-3) using the selected shift pattern Downshift executing means for performing a downshift to the target gear stage.

  According to a second aspect of the present invention, in the shift control device for an automatic transmission for a vehicle according to the first aspect, the target gear stage setting means reduces the vehicle at that time when a shift determination is made to shift down according to the shift condition. The vehicle speed after the downshift is predicted based on the speed and the shift time stored in advance according to the type of the downshift.

  According to a third aspect of the present invention, in the shift control device for an automatic transmission for a vehicle according to the first or second aspect of the invention, the coast down shift control means may appropriately set the target gear stage by the target gear stage setting means. An execution possibility determination unit that determines whether or not it is possible based on an operation state of the driver, and when it is determined that setting of the target gear stage is impossible, the target gear stage setting unit and the shift pattern selection unit The downshift by the downshift execution means is stopped, and the downshift is performed based on the actual vehicle speed at that time.

  According to a fourth aspect of the present invention, in the shift control device for an automatic transmission for a vehicle according to any one of the first to third aspects, the coast down shift control means appropriately sets the target gear stage by the target gear stage setting means. An execution possibility determination unit that determines whether or not it is possible to perform the determination based on the driving state of the vehicle. When it is determined that the target gear stage cannot be set, the target gear stage setting unit and the shift pattern The downshift by the selection means and the downshift execution means is stopped, and the downshift is performed based on the actual vehicle speed at that time.

  According to a fifth aspect of the invention, in the shift control device for an automatic transmission for a vehicle according to any one of the first to fourth aspects of the invention, (a) the storage device stores in advance a shift time required for a shift for each shift pattern. (B) the shift pattern selection means, based on the shift time stored in the storage device when there are a plurality of combinations of the plurality of shift patterns for shifting down to the target gear. A total shift time required for downshifting to the target gear stage is obtained, and a combination that minimizes the total shift time is selected.

  According to such a shift control device, the vehicle speed after the downshift is predicted, the target gear stage is set according to the shift condition based on the predicted vehicle speed, and a plurality of shift patterns stored in advance in the storage device are set. To select a single shift pattern or a combination of multiple shift patterns that minimizes the shift time required for shifting from the middle to the target gear, and to perform a down shift using the selected shift pattern By excluding gear shifting patterns that are difficult to control gear shifting, such as gear shocks, it is possible to quickly shift down to the target gear while avoiding gear shifting shocks such as engine blow up or torque loss. And the drivability such as re-acceleration performance deteriorates due to the shift speed becoming longer due to the multi-stage automatic transmission. It is suppressed.

  In the second invention, since the vehicle speed after the downshift is predicted based on the vehicle deceleration and the shift time, the vehicle speed after the downshift is obtained with high accuracy, and the target gear stage is further increased based on the vehicle speed. Coast down shift control that is set appropriately and has a short shift time is suitably performed.

  In the third and fourth inventions, it is determined whether or not the target gear stage can be appropriately set by the target gear stage setting means on the basis of the driver's operation situation and the driving situation of the vehicle, and the target gear stage is determined. If it is determined that the speed setting is not possible, the downshift is performed based on the actual vehicle speed at that time, so that the downshift toward the wrong target gear is avoided.

  In the fifth aspect of the invention, the shift time required for shifting for each shift pattern is stored in advance in the storage device, and when there are a plurality of combinations of shift patterns for downshifting to the target gear stage, the storage device Based on the stored shift time, the total shift time required to shift down to the target gear stage is obtained, and the combination that minimizes the total shift time is selected to perform the down shift. The total shift time for coasting down to the target gear stage can be shortened as much as possible while avoiding shift shocks such as slipping off.

  As the automatic transmission, a planetary gear type automatic transmission having a plurality of planetary gear devices is preferably used, but a parallel shaft type automatic transmission that changes gears by switching a plurality of input paths can also be used. Various automatic transmissions having a plurality of friction engagement devices can be employed. As the friction engagement device, a multi-plate type, single-plate type clutch or brake engaged by a hydraulic actuator, or a belt-type brake is preferably used.

  The coast down shift control means, for example, at the time of sudden deceleration such as a brake ON that requires a multi-stage shift to shift down to two or more lower gear stages, the target gear stage setting means, the shift pattern selection means, and the down shift execution means The coast down shift control is executed, but at the time of slow deceleration such as brake OFF, the normal coast down shift control is performed in which the down shift is performed only by a single shift that shifts one step at a time according to the down shift determination based on the actual vehicle speed. Is done.

  The coast down shift control at the time of sudden deceleration is, for example, when the subsequent target gear stage cannot be predicted due to the driver's operation status, when the driver's intention to decelerate is lost, or when the driver requests acceleration For example, it is desirable to prohibit the execution and to stop immediately when the operation is in progress. Specifically, for example, the operation of the brake operation device (pedal or the like) is canceled or the operation force (the pedal force) of the brake operation device is canceled. Etc.) or when an accelerator operation member (pedal or the like) is operated, it is desirable to stop or prohibit the coast down shift control during the rapid deceleration. Even when the driver requests a downshift by a manual operation, the subsequent target gear cannot be predicted. Therefore, it is desirable to similarly stop or prohibit the coastdown shift control during sudden deceleration.

  In addition to the operation of the driver, for example, when the subsequent target gear stage becomes unpredictable due to the driving situation of the vehicle, it is desirable to stop or prohibit the execution of this control. When the deceleration changes remarkably, when the vehicle slips, or when the rotational speed sensor breaks down, it is desirable to stop or prohibit the coast down shift control at the time of sudden deceleration.

  The shift pattern stored in the storage device in advance can be shifted by a series of shift control while suppressing a shift shock, for example, and is appropriately set according to the configuration of the automatic transmission, and is shifted down by one step. Of course, a single shift, a multiple shift that continuously shifts down across multiple gear stages, a jump shift that jumps down over one or more gear stages, or a single shift or multiple shift, jump A combination of speed changes is possible. Although different depending on the type of shift, in general, multiple shifts have shorter shift times than repeated single shifts, and jump shifts have shorter shift times than multiple shifts.

  For example, when the downshift determination is made across the downshift vehicle speed defined as the shift condition in accordance with the deceleration at the time of coasting with the accelerator OFF, the target gear stage setting means, the deceleration of the vehicle at that time, The vehicle speed after the downshift is predicted based on a predetermined shift time with respect to the downshift (single shift), and the target gear stage is set according to the shift condition based on the predicted vehicle speed. For example, the vehicle speed after downshifting is predicted only by the deceleration of the vehicle, or the vehicle speed after downshifting in the case of multistage shifting is determined by judging whether or not the multi-speed shifting is based on the deceleration of the vehicle at that time, etc. Other modes can also be adopted.

  The target gear stage setting means also predicts the vehicle speed after the downshift again based on the total shift time when the downshift is performed with the shift pattern selected by the shift pattern selection means, and resets the target gear stage. It is also possible to configure. If there is no change in the target gear stage in such a review of the target gear stage, it is sufficient to execute the down shift by the down shift execution means as it is, but when the target gear stage changes, the shift pattern selection means again. What is necessary is just to re-select a shift pattern.

  Each time the downshift is performed according to one shift pattern by the downshift execution means, the target gear stage is reviewed based on the vehicle speed or deceleration at that time, and the subsequent shift pattern is selected again as necessary. Various embodiments are possible, such as being able to do so.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a skeleton diagram of a horizontally-mounted vehicle drive device such as an FF (front engine / front drive) vehicle. An output of an engine 10 constituted by an internal combustion engine such as a gasoline engine includes a torque converter 12, The power is transmitted to drive wheels (front wheels) (not shown) through a power transmission device such as the automatic transmission 14 and the differential gear device 16. The torque converter 12 includes a pump impeller 20 connected to the crankshaft 18 of the engine 10, a turbine impeller 24 connected to the input shaft 22 of the automatic transmission 14, and a non-rotating member via a one-way clutch 26. And a lockup clutch 32 for directly connecting the crankshaft 18 to the input shaft 22 via a damper (not shown). A mechanical oil pump 21 such as a gear pump is connected to the pump impeller 20 and is driven to rotate together with the pump impeller 20 by the engine 10 so as to generate hydraulic pressure for shifting or lubricating. The engine 10 is a driving force source for vehicle travel, and the torque converter 12 is a fluid coupling.

  The automatic transmission 14 is coaxially disposed on the input shaft 22 and a carrier and a ring gear are connected to each other to thereby form a so-called CR-CR coupled planetary gear mechanism. A first planetary gear unit 40 and a second planetary gear unit 42; a set of third planetary gear units 46 arranged coaxially on a counter shaft 44 parallel to the input shaft 22; and a shaft end of the counter shaft 44 An output gear 48 that is fixed and meshes with the differential gear device 16 is provided. The components of the planetary gear units 40, 42, 46, that is, the sun gear, the ring gear, and the carrier that rotatably supports the planet gears meshing with them are selectively connected to each other by four clutches C0, C1, C2, and C3. Alternatively, the three brakes B1, B2, and B3 are selectively connected to the housing 28 that is a non-rotating member. The two one-way clutches F1 and F2 are engaged with each other or with the housing 28 depending on the rotation direction. Since the differential gear device 16 is configured symmetrically with respect to the axis (axle), the lower side is not shown.

  The first planetary gear unit 40, the second planetary gear unit 42, the clutches C0, C1, C2, the brakes B1, B2, and the one-way clutch F1 arranged coaxially with the input shaft 22 are moved forward and reverse by four stages. A one-stage main transmission unit MG is configured, and a set of planetary gear unit 46, clutch C3, brake B3, and one-way clutch F2 arranged on the counter shaft 44 constitute a sub-transmission unit, that is, an underdrive unit U / D. It is configured. In the main transmission unit MG, the input shaft 22 is connected to the carrier K2 of the second planetary gear device 42, the sun gear S1 of the first planetary gear device 40, and the sun gear S2 of the second planetary gear device 42 via the clutches C0, C1, and C2. Each is connected. The ring gear R1 of the first planetary gear unit 40 and the carrier K2 of the second planetary gear unit 42 are connected, and the ring gear R2 of the second planetary gear unit 42 and the carrier K1 of the first planetary gear unit 40 are connected to each other. The sun gear S2 of the second planetary gear unit 42 is connected to the housing 28 that is a non-rotating member via a brake B1, and the ring gear R1 of the first planetary gear unit 40 is a housing 28 that is a non-rotating member via a brake B2. It is connected to. A one-way clutch F1 is provided between the carrier K2 of the second planetary gear unit 42 and the housing 28 which is a non-rotating member. The first counter gear G1 fixed to the carrier K1 of the first planetary gear device 40 and the second counter gear G2 fixed to the ring gear R3 of the third planetary gear device 46 are meshed with each other. In the underdrive unit U / D, the carrier K3 and the sun gear S3 of the third planetary gear unit 46 are connected to each other via the clutch C3, and between the sun gear S3 and the housing 28 that is a non-rotating member, A brake B3 and a one-way clutch F2 are provided in parallel.

  The clutches C0, C1, C2, and C3 and the brakes B1, B2, and B3 (hereinafter simply referred to as the clutch C and the brake B unless otherwise distinguished) are controlled by a hydraulic actuator such as a multi-plate clutch or a band brake. This is a hydraulic friction engagement device, and the hydraulic circuit is switched by excitation or non-excitation of the solenoid valves S1 to S5 and the linear solenoid valves SL1, SL2, and SLU of the hydraulic control circuit 98 (see FIG. 3) and a manual valve (not shown). Thus, for example, as shown in FIG. 2, the engaged and released states are switched, and the forward, reverse, and neutral gear positions are changed according to the operation position (position) of the shift lever 72 (see FIG. 3). It is established. “1st” to “5th” in FIG. 2 mean the first to fifth forward gears, “◯” means engagement, “×” means release, and “△” means only during driving. Means engagement. The shift lever 72 is, for example, in accordance with the shift pattern shown in FIG. 4, a parking position “P”, a reverse travel position “R”, a neutral position “N”, a forward travel position “D”, “4”, “3”, “2”. In the “P” and “N” positions, a neutral gear stage is established as a non-drive gear stage that cuts off power transmission, but in the “P” position, a mechanical gear (not shown) is established. The parking mechanism mechanically prevents the drive wheels from rotating.

FIG. 3 is a block diagram for explaining a control system provided in the vehicle for controlling the engine 10 and the automatic transmission 14 of FIG. 1, and the operation amount (accelerator opening) Acc of the accelerator pedal 50 is an accelerator operation. It is detected by the quantity sensor 51. The accelerator pedal 50 is largely depressed according to the driver's requested output amount, and corresponds to an accelerator operation member, and the accelerator operation amount Acc corresponds to the requested output amount. The intake pipe of the engine 10 is provided with an electronic throttle valve 56 that changes the throttle valve opening θ _TH by controlling the throttle actuator 54 in accordance with the throttle command value TA. The throttle command value TA corresponds to the throttle valve opening θ _TH and is basically controlled according to a predetermined target throttle command value TA ^* map using the accelerator operation amount Acc as a parameter as shown in FIG. As the amount Acc increases, the target throttle command value TA ^* and further the throttle command value TA are increased, and the throttle valve opening degree _θTH is controlled to be opened to increase the engine output.

Further, an engine rotation speed sensor 58 for detecting the rotation speed NE of the engine 10, an intake air amount sensor 60 for detecting the intake air amount Q of the engine 10, and the electronic throttle valve 56 are fully closed (idle state). and idle switch with a throttle sensor 64 for detecting the opening degree theta _TH, a vehicle speed sensor 66 for detecting the rotational speed N _OUT of the counter shaft 44 corresponding to the vehicle speed V, the detecting the cooling water temperature T _W of the engine 10 a cooling water temperature sensor 68 for a brake switch 70 for detecting the presence or absence of foot brake operation, lever position (operation position) of the shift lever 72 lever position sensor 74 for detecting a P _SH, the turbine rotational speed NT (= input turbine rotation speed sensor 76 for detecting the rotational speed N _iN) of the shaft 22, the hydraulic control circuit 9 AT oil temperature sensor 78 for detecting the the temperature of the hydraulic fluid of the inner AT oil temperature T _OIL, a counter rotational speed sensor 80 for detecting it is provided a rotational speed NC of the first counter gear G1, From these sensors, the engine speed NE, the intake air amount Q, the throttle valve opening θ _TH , the vehicle speed V, the engine coolant temperature T _W , the presence or absence of brake operation, the lever position P _SH of the shift lever 72, the turbine speed NT, Signals representing the AT oil temperature T _OIL , the counter rotational speed NC, and the like are supplied to the electronic control unit 90. The brake switch 70 is an ON-OFF switch that switches between ON and OFF when the brake pedal that operates the service brake is depressed.

  The electronic control unit 90 includes a so-called microcomputer having a CPU, a RAM, a ROM, an input / output interface, and the like. The CPU uses a temporary storage function of the RAM, and signals according to a program stored in the ROM in advance. By performing processing, output control of the engine 10, shift control of the automatic transmission 14, and the like are executed. The engine control means 110 and the shift control means 120 are functionally provided as shown in FIG. Depending on the situation, the engine control and the shift control are divided.

The engine control means 110 controls the opening and closing of the electronic throttle valve 56 by the throttle actuator 54, controls the fuel injection valve 92 for controlling the fuel injection amount, and controls the ignition device 94 such as an igniter for controlling the ignition timing. At the same time, the crankshaft 18 is cranked by the starter (electric motor) 96 when the engine 10 is started. In the opening / closing control of the electronic throttle valve 56, the target throttle command value TA ^* is basically obtained from the relationship shown in FIG. 5 based on the actual accelerator operation amount Acc, and the target throttle command value TA ^* is directly used as the throttle command value TA. And the throttle actuator 54 is driven to increase the throttle valve opening θ _TH as the accelerator operation amount Acc increases. However, the target throttle command corresponding to the accelerator operation amount Acc is required by traction control or the like. A throttle command value TA different from the value TA ^* is output.

The shift control means 120 is a target gear of the automatic transmission 14 based on the actual accelerator operation amount Acc and the vehicle speed V from the shift diagram (shift map) shown in FIG. In order to change the engagement and disengagement states of the clutch C and the brake B so as to establish the target gear stage, the solenoid valves S1 to S5 of the hydraulic control circuit 98 are turned on (excited) and turned off (non- In addition, the energizing amounts of the linear solenoid valves SL1, SL2, and SLU are continuously changed so that a shift shock such as a change in driving force does not occur and the durability of the friction material is not impaired. To control the engagement hydraulic pressure. The solid line in FIG. 6 is the upshift line, and the broken line is the downshift line. As the vehicle speed V decreases or the accelerator operation amount Acc increases, the gear ratio (= input rotational speed N _IN / output rotational speed N _OUT ) Can be switched to a low speed side gear stage, and “1” to “5” in the figure mean the first speed gear stage “1st” to the fifth speed gear stage “5th”. .

  The shift control means 120 also includes coast down shift control means 122 that shifts down the automatic transmission 14 as the vehicle decelerates when the accelerator pedal 50 is coasted with the accelerator pedal 50 not being depressed. Using the shift conditions (shift diagram) stored in the condition storage unit 130 and the shift pattern information stored in the shift pattern storage unit 132, coast down shift control is performed according to the flowchart of FIG. The shift pattern information stored in the shift pattern storage means 132 is, for example, a shift pattern as shown in FIG. 9 and its shift time, and the shift pattern is relatively easy to control and prevents the occurrence of a shift shock. Shifting can be performed by a series of shift control, which is appropriately set according to the configuration of the automatic transmission 14 and is not limited to a single shift (No. 1 to No. 4 in FIG. 9) that shifts down by one step. Multiple shifts (No7, No9, No10 in FIG. 9) that continuously shift down over the distance, jump shifts (No5, No6 in FIG. 9) that jump down one or more gears, or 9 (No. 8 in FIG. 9) is set. The shift time is set to, for example, a fixed time for each shift pattern, but the vehicle state such as deceleration can also be determined as a parameter. The shift pattern storage means 132 corresponds to a storage device, and the shift pattern storage means 132 and the shift condition storage means 130 are constituted by the RAM or the like, for example. 8 corresponds to execution feasibility determination means, steps S3 and S4 correspond to target gear setting means, step S5 corresponds to shift pattern selection means, and steps S6 to S8 correspond to down shift execution means. It corresponds to.

  In step S1 of FIG. 8, it is determined whether or not a coast down shift is performed, that is, whether or not the vehicle speed V crosses the down shift line as the vehicle is decelerated during coasting with the accelerator off. This is executed to determine whether coast downshift control during sudden deceleration is possible. The coast down shift control at the time of sudden deceleration is a control in the case of performing a multi-stage shift that shifts to a lower gear stage by two or more stages in a short time at the time of sudden deceleration such as brake ON, and basically the brake switch 70 is ON and This is executed when the vehicle deceleration is greater than or equal to a predetermined value, but when it is determined in steps S3 and S4 that it is impossible to appropriately set the target gear stage according to the driver's operation status or vehicle driving status, If it is determined that the subsequent gear position cannot be predicted appropriately, the coast down shift control during the rapid deceleration after step S3 is stopped. Specifically, when the driver's brake operation is released, the brake operation force is weakened, or when the accelerator pedal 50 is depressed, it is difficult to predict the subsequent gear stage appropriately. It is. It is also difficult to predict the subsequent gear stage if the vehicle deceleration changes significantly, if the vehicle slips, or if the rotational speed sensor breaks down. It is determined whether the coast down shift control at the time of rapid deceleration can be appropriately performed according to the determination condition. The determination as to whether or not step S2 can be performed is appropriately performed even during the execution of the coast downshift control during the rapid deceleration after step S3, and the execution is stopped as necessary.

  If it is determined that coast-down shift control during sudden deceleration is not possible due to slow deceleration of the brake OFF or the target gear stage being unpredictable, the determination in step S2 is NO (negative) and step S9 is executed. To do. In step S9, in accordance with the downshift determination in step S1 based on the actual vehicle speed V, normal coast downshift control is performed in which the downshift is performed only by a single shift that shifts by one step.

On the other hand, if coast downshift control during sudden deceleration is possible and the determination in step S2 is YES (affirmative), step S3 is executed, and the shift ends when the downshift is performed by one step in accordance with the downshift determination in step S1. The subsequent predicted vehicle speed Vd is calculated (predicted) according to the following equation (1) based on the vehicle speed V, the deceleration ΔV, and the shift time Td at that time. The shift time Td is read from the shift pattern information stored in the shift pattern storage means 132 according to the type of shift at that time.
Vd = V− (ΔV × Td) (1)

  In the next step S4, the target gear stage is set according to the shift diagram of FIG. 6 based on the predicted vehicle speed Vd. That is, the gear stage when the vehicle is decelerated to the expected vehicle speed Vd is determined according to the downshift line, and the gear stage is set as the target gear stage.

  In step S5, a single shift pattern or a plurality of shift patterns having the shortest shift time required for downshifting to the target gear stage is selected from the shift patterns stored in the shift pattern storage means 132. Select a combination. At this time, when a downshift is performed with a combination of a plurality of shift patterns, and there are a plurality of combinations, all the combinations of the shift patterns are obtained, and the total shift time at the time of the downshift by the combination of each shift pattern Is calculated from the shift time stored in the shift pattern storage means 132, and a combination of shift patterns that is optimal, that is, the shortest total shift time is selected. For example, when shifting from the fifth speed gear stage “5th” to the first speed gear stage “1st” due to sudden deceleration, nine combinations No. 1 to No. 9 are possible as shown in FIG. In addition to calculating the time, a combination of shift patterns having the shortest total shift time is selected, in this case, a combination of two shift patterns of No. 8 5 → 4 → 3 multiple shift and 3 → 1 jump shift.

  In step S6, a coast-down shift is performed for each shift pattern. Here, first, a shift command for performing a multiple shift of 5 → 4 → 3 is output, so that the solenoid valves S1 to S5 of the hydraulic control circuit 98 are output. The engagement / release hydraulic pressure is controlled by changing the ON / OFF state of the clutch C and the brake B to change the engagement / release state of the clutch C and continuously changing the energization amounts of the linear solenoid valves SL1, SL2, and SLU. In step S7, whether or not the coast down shift of one shift pattern has been completed, that is, whether or not a series of hydraulic control for shifting has been completed, whether the solenoid valves S1 to S5 or the linear solenoid valves SL1, SL2, Judgment is made based on the output state of the command signal to the SLU, and when coast downshifting of one shift pattern is completed, step S8 is executed.

  In step S8, it is determined whether or not the downshift has been performed to the target gear stage based on the output state of the command signal to the solenoid valves S1 to S5. If the downshift is performed to the target gear stage, a series of coast downshift control is terminated. However, if the target gear stage has not been reached, step S6 and subsequent steps are repeated to perform the coast down shift of the next shift pattern. Here, only the multiple shift of 5 → 4 → 3 is performed, and the gear stage of the automatic transmission 14 is the third speed gear stage “3rd”, and the jump shift of 3 → 1 still remains. Step S6 and subsequent steps are executed to execute a jump shift of 3 → 1. When the 3 → 1 jump shift is completed, the determination in step S8 is YES and the series of coast down shift control is terminated.

  As described above, the shift control apparatus according to the present embodiment executes step S3 and subsequent steps when the determination of the coast down shift at the time of sudden deceleration is made and both the determinations of steps S1 and S2 are YES. In addition to obtaining the predicted vehicle speed Vd after the downshift by the single shift, in step S4, the target gear stage is set based on the predicted vehicle speed Vd, and among the plurality of shift patterns stored in advance in the shift pattern storage means 132, A single shift pattern or a combination of a plurality of shift patterns that minimizes the shift time required for downshifting to the target gear stage is selected, and the downshift is performed using the selected shift pattern. In that case, the shift pattern storage means 132 is set only with a shift pattern in which the shift control is relatively easy and the shift can be performed by a series of shift control while preventing the occurrence of shift shock. It is possible to perform coast-down gear shifting quickly to the target gear while avoiding gear shifting shocks such as air blows up or torque is lost. Deterioration of drivability such as performance is suppressed.

  In particular, in this embodiment, when the shift time required for shifting is stored in advance in the shift pattern storage means 132 for each shift pattern, and there are a plurality of shift pattern combinations for downshifting to the target gear stage. Based on the shift time stored in the shift pattern storage means 132, the total shift time required to shift down to the target gear stage is obtained, and the combination of shift patterns that minimizes the total shift time is selected. Since the coast down shift is performed in order according to the combination of the selected shift patterns, the total shift time required for the coast down shift to the target gear stage can be shortened as much as possible.

  Further, in this embodiment, the predicted vehicle speed Vd after the downshift is calculated according to the equation (1) based on the vehicle speed V, the deceleration ΔV, and the shift time Td, so the accuracy of the predicted vehicle speed Vd after the downshift is high. At the same time, the target gear is set more appropriately based on the predicted vehicle speed Vd, and coast down shift control with a short shift time is suitably performed.

  In step S2, it is determined whether or not it is possible to appropriately set the target gear based on the driver's operation status and the vehicle driving status, and when it is determined that the target gear cannot be set. Stops the coast down shift control at the time of sudden deceleration in step S3 and below, and executes the normal coast down shift control for performing the down shift based on the actual vehicle speed V at that time in step S9. Downshifting toward is avoided.

  As mentioned above, although the Example of this invention was described in detail based on drawing, this is an embodiment to the last, and this invention is implemented in the aspect which added various change and improvement based on the knowledge of those skilled in the art. Can do.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a skeleton diagram illustrating a configuration of a vehicle drive device to which the present invention is preferably applied. FIG. 2 is a diagram illustrating an engagement / release state of a clutch and a brake for establishing each gear stage of the automatic transmission of FIG. 1. FIG. 2 is a block diagram illustrating a control system that performs engine control and shift control of the vehicle drive device of FIG. 1. It is a figure which shows an example of the shift pattern of the shift lever of FIG. FIG. 4 is a diagram illustrating an example of a relationship between an accelerator operation amount Acc used in throttle control performed by the electronic control device of FIG. 3 and a target throttle command value TA ^* . It is a figure which shows an example of the shift map (map) used by the shift control of the automatic transmission performed by the electronic controller of FIG. It is a block diagram explaining the principal part of the control function of the electronic control apparatus of FIG. FIG. 8 is a flowchart for specifically explaining the processing contents of the coast down shift control means of FIG. 7. FIG. It is a figure which shows an example of the shift pattern information memorize | stored in the shift pattern memory | storage means of FIG. It is a figure explaining an example of the combination of the selectable shift pattern calculated | required by step S5 of FIG.

Explanation of symbols

14: Automatic transmission 90: Electronic control unit 122: Coast down shift control unit 132: Shift pattern storage unit (storage unit) C0, C1, C2, C3: Clutch (friction engagement device) B1, B2, B3: Brake ( Friction engagement device)
Step S2: Executability determination unit Steps S3 and S4: Target gear setting unit Step S5: Shift pattern selection unit Steps S6 to S8: Down shift execution unit

Claims (5)

An automatic transmission in which a plurality of gear stages having different gear ratios are established by selectively engaging a plurality of friction engagement devices;
Coast down shift control means for performing a down shift according to a predetermined shift condition with a vehicle speed as a parameter when the accelerator is decelerated;
In a shift control device for a vehicle automatic transmission having
While a plurality of shift patterns that can be shifted by a series of shift control during the down shift are stored in the storage device in advance,
The coast down shift control means includes:
Target gear stage setting means for predicting a vehicle speed after downshifting, and setting a target gear stage according to the shift condition based on the predicted vehicle speed;
From among a plurality of shift patterns stored in the storage device, a single shift pattern or a combination of a plurality of shift patterns that minimizes the shift time required for downshifting to the target gear stage is selected. Shift pattern selection means;
Downshift execution means for downshifting to the target gear using the selected shift pattern;
A shift control apparatus for an automatic transmission for a vehicle, comprising: The shift control device for an automatic transmission for a vehicle according to claim 1,
The target gear stage setting means, based on the deceleration of the vehicle at that time and the shift time stored in advance according to the type of the downshift when the shift determination to be downshifted is made according to the shift condition. A shift control device for an automatic transmission for a vehicle, wherein the vehicle speed after downshifting is predicted. The shift control device for an automatic transmission for a vehicle according to claim 1 or 2,
The coast down shift control means has execution feasibility determination means for determining whether or not the target gear stage can be appropriately set by the target gear stage setting means based on an operation state of a driver, If it is determined that the target gear stage cannot be set, the downshift by the target gear stage setting means, the shift pattern selection means, and the downshift execution means is stopped, and the downspeed is reduced based on the actual vehicle speed at that time. A shift control device for an automatic transmission for a vehicle, wherein the shift is performed. The shift control device for an automatic transmission for a vehicle according to any one of claims 1 to 3,
The coast down shift control means includes execution feasibility determining means for determining whether or not the target gear stage can be appropriately set by the target gear stage setting means based on a driving situation of the vehicle. If it is determined that the gear position cannot be set, the downshift by the target gear stage setting means, the shift pattern selection means, and the downshift execution means is stopped, and the downshift is performed based on the actual vehicle speed at that time. A shift control apparatus for an automatic transmission for a vehicle. In the shift control device for an automatic transmission for a vehicle according to any one of claims 1 to 4,
The storage device stores in advance a shift time required for shifting for each shift pattern,
When there are a plurality of combinations of the plurality of shift patterns for downshifting to the target gear stage, the shift pattern selecting means performs downshifting to the target gear stage based on the shift time stored in the storage device. A shift control apparatus for an automatic transmission for a vehicle, characterized in that a total shift time required for the operation is obtained and a combination that minimizes the total shift time is selected.

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