JP2018013119A - Control device of vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress a shock accompanied by an abrupt change of the input torque of an automatic transmission when performing torque limit control at a power-on downshift.SOLUTION: When it is assumed that input torque Ti at a start of torque limit control at the execution of a first downshift exceeds a prescribed torque limit value by the execution of a second downshift at a required coast-time require power-on downshift in a state that the execution of the required first downshift is delayed in deceleration traveling in an inertia traveling state, or when the input torque Ti at the start of the torque limit control is specified to exceed the prescribed torque limit value, smoothening processing for loosening a torque change speed when setting the input torque Ti to the prescribed torque limit value or smaller at the torque limit control is performed. By this constitution, when performing the torque limit control at a time of the coast-time required power-on downshift, a shock accompanied by an abrupt change of the input torque Ti of an automatic transmission 22 can be suppressed.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a vehicle control apparatus including an automatic transmission that transmits power from a power source.

  2. Description of the Related Art A vehicle control device including an automatic transmission that transmits power from a power source is well known. For example, this is the control device for an automatic transmission described in Patent Document 1. In Patent Document 1, in a control device for an automatic transmission that shifts and outputs engine rotation input via a torque converter, a non-lock-up state is detected, the vehicle speed is other than a predetermined vehicle speed, and the engine If it is determined that the load has changed from less than a predetermined value to a predetermined value or more, the coast state (inertia) is started by starting suppression of engine torque after a predetermined time set based on the engine load has elapsed since the determination of engine load change. It is disclosed that torque fluctuations or shocks that occur when shifting from a running state) to an accelerator-on state (drive state, accelerated running state) can be efficiently suppressed.

JP 2007-327477 A

  By the way, there is a case where the downshift of the automatic transmission is performed by a power-on downshift required in accordance with the switching from the inertia running state to the acceleration running state. Even when this power-on downshift is performed, it is conceivable to perform torque limit control that suppresses the torque of the power source because it involves a transition from the inertial traveling state to the accelerated traveling state. In the power-on downshift requested in a state where the first downshift requested in the inertial traveling state is delayed, the second downshift requested in the inertial traveling state before the first downshift is performed. If torque limit control is not executed when performed, the input torque of the automatic transmission may exceed the torque limit value at the start of torque limit control when the first downshift is performed by power-on downshift. is assumed. Then, the input torque changes suddenly toward the torque limit value by the torque limit control, and a shock (for example, a feeling of stall due to a sudden decrease in the drive torque) may occur.

  The present invention has been made against the background of the above circumstances, and the object of the present invention is to suppress a shock associated with a sudden change in input torque of an automatic transmission when torque limit control is performed during a power-on downshift. It is an object of the present invention to provide a vehicle control device that can perform the above-described operation.

  The gist of the first invention is (a) a control device for a vehicle including an automatic transmission for transmitting power from a power source, and (b) a first downshift of the automatic transmission. In order to limit the input torque of the automatic transmission to a predetermined torque limit value or less when the automatic transmission power-on downshift is required as a result of switching from the inertia running state to the acceleration running state. A power source control unit that executes torque limit control of the power source; and (c) the power source control unit is configured to reduce the first down of the automatic transmission during deceleration traveling in the inertia traveling state. Requested during a transient in which execution of the requested first downshift is delayed until the second downshift is completed following a second downshift required at higher vehicle speeds than the shift Power on downshift When the first downshift is performed, or when the input torque at the start of the torque limit control exceeds the predetermined torque limit value, the input torque is set to the predetermined torque in the torque limit control. The purpose is to perform a smoothing process to moderate the torque change speed when the value is less than or equal to the limit value.

  According to a second aspect of the invention, in the vehicle control device according to the first aspect of the invention, the power source control unit is a coast downshift that is requested while the first downshift remains in the inertial running state. Other than that, even if the first downshift is performed by the power-on downshift, the torque limit control is not executed.

  According to the first aspect of the present invention, it is requested when the execution of the first downshift requested during the deceleration traveling in the inertia traveling state is delayed and the switching from the inertia traveling state to the acceleration traveling state is performed. When the second downshift requested before the first downshift is executed in the power-on downshift, the input torque of the automatic transmission at the start of torque limit control when the first downshift is executed Is assumed to exceed the predetermined torque limit value, or when it is specified that the input torque of the automatic transmission at the start of the torque limit control exceeds the predetermined torque limit value. In the control, since the smoothing process is performed to moderate the torque change speed when the input torque is less than or equal to the predetermined torque limit value, the input torque of the automatic transmission moves toward the predetermined torque limit value. It is slowly changing Te. Therefore, when torque limit control is performed during a power-on downshift, it is possible to suppress a shock associated with a sudden change in input torque of the automatic transmission.

  According to the second aspect of the invention, the first downshift is performed by a power-on downshift, except that the first downshift is a coast downshift that is required in the coasting state. Since the torque limit control is not executed, if the first downshift is a downshift requested by the accelerator operation, the torque limit control is not executed even if the power-on downshift is performed, and a desired drive torque is obtained. It becomes easy.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure explaining the schematic structure of the vehicle to which this invention is applied, and is a figure explaining the principal part of the control function and various control systems for various control in a vehicle. It is a skeleton diagram explaining an example of a torque converter and an automatic transmission. It is an action | operation chart explaining the relationship between the speed change operation | movement of an automatic transmission, and the combination of the action | operation of the engagement apparatus used for it. It is a figure which shows an example of each when not performing, when performing a torque limitation control of an engine, when performing a coast downshift request | requirement by the request | requirement power-on downshift at the time of a coast. 7 is a flowchart for explaining a control operation for suppressing a shock caused by a sudden change in an input torque of an automatic transmission when torque limiting control is performed at the time of a required power-on downshift during coasting, that is, a control operation of the electronic control device. It is a figure which shows an example of the time chart at the time of performing the control action shown to the flowchart of FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a diagram illustrating a schematic configuration of a vehicle 10 to which the present invention is applied, and a diagram illustrating a main part of a control system for various controls in the vehicle 10. In FIG. 1, a vehicle 10 includes an engine 12, a drive wheel 14, a vehicle power transmission device 16 (hereinafter referred to as a power transmission device 16) provided in a power transmission path between the engine 12 and the drive wheel 14. It has. A power transmission device 16 includes a case 18 as a non-rotating member attached to a vehicle body, a torque converter 20, an automatic transmission 22, and a reduction gear connected to a transmission output gear 24 that is an output rotating member of the automatic transmission 22. A mechanism 26, a differential gear (differential gear device) 28 connected to the reduction gear mechanism 26, and the like are provided. The power transmission device 16 also includes a pair of drive shafts (axles) 30 connected to the differential gear 28. In the power transmission device 16, the power output from the engine 12 (torque and force are synonymous unless otherwise specified) is a torque converter 20, an automatic transmission 22, a reduction gear mechanism 26, a differential gear 28, a drive shaft 30, and the like. Are sequentially transmitted to the drive wheel 14.

  The engine 12 is a driving power source (a power source is also agreed) of the vehicle 10, and is a known internal combustion engine such as a gasoline engine or a diesel engine. The engine torque Te of the engine 12 is controlled by controlling an operating state such as an intake air amount, a fuel supply amount, an ignition timing and the like by an electronic control unit 70 described later.

  FIG. 2 is a skeleton diagram illustrating an example of the torque converter 20 and the automatic transmission 22. The torque converter 20, the automatic transmission 22, and the like are configured substantially symmetrically with respect to the axis RC of the transmission input shaft 32 that is an input rotation member of the automatic transmission 22, and in FIG. The lower half of RC is omitted.

  In FIG. 2, the torque converter 20 is disposed so as to rotate about the axis RC in the power transmission path between the engine 12 and the automatic transmission 22, and is connected to the engine 12. , And a hydrodynamic transmission device including a turbine impeller 20t connected to the transmission input shaft 32, and the like. The transmission input shaft 32 is also a turbine shaft that is rotationally driven by the turbine impeller 20t. The power transmission device 16 includes a lock-up clutch LC that can directly connect the pump impeller 20p and the turbine impeller 20t (that is, between the input and output rotating members of the torque converter 20). The power transmission device 16 includes a mechanical oil pump 34 connected to the pump impeller 20p. The oil pump 34 is driven to rotate by the engine 12 and discharges hydraulic oil for use in shift control of the automatic transmission 22 and for supplying lubricating oil to each part of the power transmission path of the power transmission device 16. To do. That is, the hydraulic oil pumped up by the oil pump 34 is supplied as the original pressure of the hydraulic control circuit 50 (see FIG. 1) provided in the vehicle 10.

  The automatic transmission 22 is a stepped automatic transmission that constitutes a part of a power transmission path between the engine 12 and the drive wheels 14. The automatic transmission 22 has a double pinion type first planetary gear device 36 and a single pinion type second planetary gear device 38 and a double pinion type third planetary gear device 40 which are configured in a Ravigneaux type coaxially. This is a planetary gear type multi-stage transmission on the line (on the axis RC). The automatic transmission 22 includes a plurality of engagement devices for the first clutch C1, the second clutch C2, the third clutch C3, the fourth clutch C4, the first brake B1, and the second brake B2. Simply referred to as an engagement device C).

  The first planetary gear device 36 includes a first sun gear S1, a plurality of pairs of first planetary gears P1 that mesh with each other, a first carrier CA1 that supports the first planetary gear P1 so as to be capable of rotating and revolving, and a first planetary gear. A first ring gear R1 meshing with the first sun gear S1 via P1 is provided. The second planetary gear unit 38 includes a second sun gear S2, a second planetary gear P2, a carrier RCA that supports the second planetary gear P2 so as to rotate and revolve, and a second sun gear via the second planetary gear P2. A ring gear RR that meshes with S2 is provided. The third planetary gear device 40 includes a third sun gear S3, a plurality of pairs of third planetary gears P3a and P3b that mesh with each other, a carrier RCA that supports the third planetary gears P3a and P3b so as to be capable of rotating and revolving, A ring gear RR that meshes with the third sun gear S3 through planetary gears P3a and P3b is provided. In the second planetary gear device 38 and the third planetary gear device 40, the third planetary gear P3b is shared with the second planetary gear P2, and the carrier is constituted by the common carrier RCA and the ring gear is shared. It is a so-called Ravigneaux type composed of RR.

  The engagement device C is a hydraulic friction engagement device including a wet multi-plate clutch and brake pressed by a hydraulic actuator, a band brake tightened by the hydraulic actuator, and the like. The engagement device C is controlled by each hydraulic pressure (clutch pressure) Pc (that is, clutch pressure Pc1, Pc2, Pc3, Pc4, Pb1, Pb2) output from each solenoid valve SL1-SL6 or the like in the hydraulic control circuit 50. By changing the torque capacity (clutch torque) Tc (that is, clutch torques Tc1, Tc2, Tc3, Tc4, Tb1, Tb2), the operating states (engaged and released states) are respectively switched. Torque (for example, input to the transmission input shaft 32) between the transmission input shaft 32 and the transmission output gear 24 without sliding the engagement device C (that is, without causing the differential rotation speed of the engagement device C). In order to transmit the input torque Ti (that is, the turbine torque Tt) to be transmitted, a torque capacity capable of obtaining a transmission torque (that is, a shared torque of the engagement device C) required to be handled by each engagement device C with respect to the torque. Is required. However, in the torque capacity that provides the transmission torque, the transmission torque does not increase even if the torque capacity is increased. In the present embodiment, for the sake of convenience, the clutch torque Tc and the clutch pressure Pc may be treated synonymously.

  In the automatic transmission 22, the first sun gear S <b> 1 is connected to the case 18. The first carrier CA1 is connected to the transmission input shaft 32. The first carrier CA1 and the second sun gear S2 are selectively connected via a fourth clutch C4. The first ring gear R1 and the third sun gear S3 are selectively coupled via the first clutch C1. The first ring gear R1 and the second sun gear S2 are selectively connected via a third clutch C3. The second sun gear S2 is selectively connected to the case 18 via the first brake B1. The carrier RCA is selectively coupled to the transmission input shaft 32 via the second clutch C2. The carrier RCA is selectively coupled to the case 18 via the second brake B2. The ring gear RR is connected to the transmission output gear 24.

  The automatic transmission 22 is controlled by an electronic control device 70 described later to engage and release a predetermined engagement device of the engagement devices C according to the accelerator operation of the driver, the vehicle speed V, and the like. This is a stepped transmission in which a plurality of gear stages (shift stages) having different gear ratios (gear ratios) γ (= AT input rotation speed Ni / AT output rotation speed No) are selectively formed. For example, as shown in the engagement operation table of FIG. 3, the automatic transmission 22 includes eight forward gear stages “1st speed gear stage“ 1st ”−8th speed gear stage“ 8th ”” and reverse gear stage “Rev”. Each gear stage is selectively formed. The AT input rotational speed Ni is the rotational speed of the transmission input shaft 32, and the AT output rotational speed No is the rotational speed of the transmission output gear 24. The gear ratio γ of the automatic transmission 22 corresponding to each gear stage is the gear ratio of the first planetary gear device 36, the second planetary gear device 38, and the third planetary gear device 40 (= the number of teeth of the sun gear / the number of ring gears). The number of teeth) is appropriately determined according to ρ1, ρ2, ρ3. The gear ratio γ of the first speed gear stage “1st” is the largest, and becomes smaller as the vehicle speed increases (the eighth speed gear stage “8th” side).

  The engagement operation table of FIG. 3 summarizes the relationship between each gear stage formed in the automatic transmission 22 and each operation state of the engagement device C, “◯” indicates engagement, and blank indicates release. Respectively. As shown in FIG. 3, at the forward gear stage, the first speed gear stage “1st” is established by the engagement of the first clutch C1 and the second brake B2. The second gear stage “2nd” is established by engagement of the first clutch C1 and the first brake B1. The third gear stage “3rd” is established by engagement of the first clutch C1 and the third clutch C3. The fourth gear stage “4th” is established by engagement of the first clutch C1 and the fourth clutch C4. The fifth gear "5th" is established by engagement of the first clutch C1 and the second clutch C2. The sixth gear stage "6th" is established by engagement of the second clutch C2 and the fourth clutch C4. The seventh gear stage "7th" is established by engagement of the second clutch C2 and the third clutch C3. The eighth gear stage "8th" is established by engagement of the second clutch C2 and the first brake B1. Further, the reverse gear stage “Rev” is established by the engagement of the third clutch C3 and the second brake B2. Further, when any of the engagement devices C is released, the automatic transmission 22 is in a neutral state in which no gear stage is formed (that is, a neutral state in which power transmission is interrupted).

  Returning to FIG. 1, the vehicle 10 includes an electronic control unit 70 including a control unit for the vehicle 10 related to, for example, shift control of the automatic transmission 22. Therefore, FIG. 1 is a diagram showing an input / output system of the electronic control unit 70, and is a functional block diagram for explaining a main part of a control function by the electronic control unit 70. The electronic control unit 70 includes, for example, 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 follows a program stored in the ROM in advance. Various controls of the vehicle 10 are executed by performing signal processing. For example, the electronic control unit 70 performs output control of the engine 12, shift control of the automatic transmission 22, and the like, and is used for engine output control, hydraulic control (for shift control), etc. as necessary. Separately configured.

  The electronic control unit 70 includes various sensors provided in the vehicle 10 (for example, an engine rotation speed sensor 52, an input rotation speed sensor 54, an output rotation speed sensor 56, an accelerator opening sensor 58, a throttle valve opening sensor 60, a brake). Various signals (for example, engine rotational speed Ne, turbine shaft rotational speed (that is, turbine rotational speed Nt)) AT input rotational speed Ni, vehicle speed V based on detection values by switch 62, shift position sensor 64, oil temperature sensor 66, etc. AT output rotation speed No corresponding to, accelerator opening θacc which is the operation amount of the accelerator pedal, throttle valve opening θth which is the opening of the electronic throttle valve, operation by the driver of the brake operation member for operating the wheel brake Brake-on Bon, “P”, “R”, “N” are signals indicating the brake operation state for which , The operation position of the shift lever, such as "D" (shift position) POSsh, such as temperature at which the working oil temperature THoil of the hydraulic oil in the hydraulic control circuit 50) is supplied. Also, from the electronic control unit 70, various command signals (for example, an engine control command signal Se, a hydraulic control command signal Sat, etc.) are respectively sent to each device (for example, the engine 12, the hydraulic control circuit 50, etc.) provided in the vehicle 10. Supplied. This hydraulic control command signal Sat is a command signal (hydraulic command value, command pressure) for driving each solenoid valve SL1-SL6 that regulates each clutch pressure Pc supplied to each hydraulic actuator of the engagement device C. And output to the hydraulic control circuit 50.

  The electronic control unit 70 includes a power source control unit, that is, a power source control unit 72, and a shift control unit, that is, a shift control unit 74 in order to realize control functions for various controls in the vehicle 10.

  The power source control unit 72, for example, determines the accelerator opening θacc and the vehicle speed V (AT output rotation speed No) in relation (for example, a driving force map) that is obtained experimentally or design in advance and stored (that is, a predetermined map). The required driving force Fdem is calculated by applying the same). The power source control unit 72 sets a target engine torque Tetgt from which the required driving force Fdem is obtained in consideration of transmission loss, auxiliary load, gear ratio γ of the automatic transmission 22, and the like. As obtained, an engine control command signal Se for controlling the output of the engine 12 is output to a throttle actuator, a fuel injection device, an ignition device, and the like.

  The shift control unit 74 determines the shift of the automatic transmission 22 by determining, for example, whether or not the gear change control of the automatic transmission 22 is executed using a predetermined relationship (shift map, shift diagram). . The shift control unit 74 determines the shift of the automatic transmission 22 by applying the vehicle speed related value and the requested drive amount to the shift map (that is, determines the gear stage formed by the automatic transmission 22). The shift control unit 74 uses a hydraulic control command signal Sat as a hydraulic control command signal as a shift command to engage and / or release the engagement device C involved in the shift of the automatic transmission 22 so as to form the determined gear stage. Output to the circuit 50.

  The shift map has a predetermined relationship having shift lines for determining the shift of the automatic transmission 22 on the two-dimensional coordinates having the vehicle speed related value and the required drive amount as variables. Each shift line in the shift map is an up line for determining an upshift and a down line for determining a downshift. The up line and the down line are determined in advance for each of the gear stages that are different from each other by a plurality of gear stages. Each of these shift lines is whether or not the actual vehicle speed related value crosses the line on a line indicating a certain drive request amount, or whether or not the actual drive request amount crosses the line on a line indicating a certain vehicle speed related value, That is, it is for determining whether or not a value (shift point) at which the shift on the shift line is to be executed has been crossed, and is predetermined as a series of shift points. The vehicle speed related value is a value related to the vehicle speed V or the vehicle speed V, and is, for example, the vehicle speed V, the wheel speed, the AT output rotation speed No, or the like. The drive request amount is a value that represents the magnitude of the drive request for the vehicle 10 by the driver. For example, the request drive force Fdem [N], the request drive torque [Nm] or the request related to the request drive force Fdem described above. Drive power [W] and the like. As the required drive amount, it is also possible to simply use the accelerator opening θacc [%], the throttle valve opening θth [%], the intake air amount [g / sec], or the like.

  When the automatic transmission 22 is shifted, the shift control unit 74 re-engages the engagement device involved in the shift of the automatic transmission 22 as the predetermined engagement device among the engagement devices C (that is, the predetermined transmission device). The engagement device is switched between engagement and release), so-called clutch-to-clutch shift is performed. For example, in the 3 → 2 downshift from the third speed gear stage “3rd” to the second speed gear stage “2nd”, the third clutch C3 and the first brake B1 perform the gripping change (that is, the third clutch The clutch-to-clutch shift for releasing the C3 and engaging the first brake B1 is executed).

  Here, the control during the downshift of the automatic transmission 22 will be described in detail. The downshift of the automatic transmission 22 includes a power-on downshift in which a downshift is determined (requested) due to an increase in the required amount of driving (for example, the accelerator opening θacc) from the accelerator depressing or the accelerator turning off to the driving request. It can be roughly classified into a power-off downshift in which a downshift is determined (requested) by a decrease in the amount (for example, accelerator opening θacc) or a decrease in a vehicle speed related value (for example, vehicle speed V) during deceleration traveling due to accelerator off. In particular, among the power-off downshifts, the downshift requested while the accelerator off coasting state (coast state) is a coast downshift. Among the down lines, the coast down line for determining the downshift when the accelerator opening degree θacc is zero (or zero and substantially zero) is set to a lower vehicle speed side than down lines other than the coast down line. As a result, the high gear stage is maintained at a lower vehicle speed and the AT input rotational speed Ni is set to a low rotational speed. For example, the difference in the synchronous rotational speed (= No × speed ratio γ) of the AT input rotational speed Ni before and after the downshift. Is reduced to suppress shift shock.

  In addition, if the coasting downshift state is changed from the coasting state with the accelerator off to the acceleration traveling state (driving state) with the accelerator on, the downshift will proceed in the acceleration traveling state. Include in shift. Accordingly, the power-on downshift of the automatic transmission 22 (referred to as coast-required power-on downshift) required when switching from the inertial running state to the acceleration running state is the power required to be downshifted by the accelerator on. Includes an on downshift and a power on downshift required by accelerator on during a coast downshift transition. Accordingly, the downshift of the automatic transmission 22 in the coast required power-on downshift is a downshift requested by the accelerator operation and a coast downshift requested in the coasting state.

  In the coast-required power-on downshift, it is preferable to limit the increase in the engine torque Te from the viewpoint of suppressing a shock or the like that occurs when shifting from the coasting traveling state to the acceleration traveling state. The downshift on the low gear stage required on the low vehicle speed side is a shift on the low vehicle speed side compared to the downshift on the high gear stage side required on the high vehicle speed side. By reducing the difference between the synchronous rotational speeds of the front and rear AT input rotational speeds Ni, the AT input rotational speed Ni is likely to blow.

  Therefore, when the first downshift of the automatic transmission 22 is performed by the coast required power on downshift (that is, the automatic transmission 22 is reduced in the coast required power on downshift). When the shift is the first downshift), torque limit control of the engine 12 is executed so as to limit the input torque Ti of the automatic transmission 22 to a predetermined torque limit value or less. The power source control unit 72 performs a retard control, a fuel suppression control, a throttle control or the like so as to limit the input torque Ti to a predetermined torque limit value or less with respect to the target engine torque Tetgt according to the accelerator opening θacc or the like. The torque limit control of the engine 12 is executed by limiting the output of the engine 12. The power source control unit 72 executes torque limit control of the engine 12 until, for example, the end of the inertia phase in the coast required power-on downshift. Since the torque limit control of the engine 12 outputs the engine torque Te that is lower than the target engine torque Tetgt, it is also a torque down control of the engine 12. The first downshift is a downshift on the low gear stage side that needs to execute torque limit control of the engine 12 in order to make it easier to blow at the AT input rotational speed Ni due to, for example, coast required power-on downshift. This is a shift pattern predetermined as a shift. In the present embodiment, the shift pattern serving as the first downshift is 2 → 1 downshift. The predetermined torque limit value is, for example, a predetermined upper limit value for appropriately suppressing the blowing of the AT input rotational speed Ni during a coast required power on downshift. The input torque Ti (= turbine torque Tt) is the same as the engine torque Te (= Ti / t) when the torque ratio t of the torque converter 20 is taken into consideration.

  Further, when the first downshift is a downshift requested by an accelerator operation, it is preferable to prioritize the acceleration request over the shock suppression or the like as compared with the coast downshift. In addition, the coast downshift required due to the decrease in the vehicle speed V is a shift on the low vehicle speed side as compared with the downshift required by the accelerator operation. Therefore, the synchronous rotational speed of the AT input rotational speed Ni before and after the downshift. When the difference between the two is reduced, the AT input rotation speed Ni is easily blown. For this reason, the power source control unit 72 determines the torque of the engine 12 even if the first downshift is a coast-time required power-on downshift, except that the first downshift is a coast downshift. Does not execute limit control.

  FIG. 4 is a diagram illustrating an example of a case where the torque limit control of the engine 12 is executed and a case where it is not executed when the coast downshift request is executed by the coast required power-on downshift. In FIG. 4, at the time of coast required power on downshift due to accelerator on (time t2) after the shift command (time t1) of n → (n-1) downshift required during deceleration traveling in the inertial running state, n → (n−1) downshift other than the first downshift (for example, 2 → 1 downshift), the downshift on the high gear stage required on the higher vehicle speed side than the first downshift. In the case of the second downshift of the automatic transmission 22, the torque limit control of the engine 12 is not executed as indicated by the solid line of the input torque Ti, and the input torque Ti corresponding to the accelerator opening θacc is can get. On the other hand, when the n → (n−1) downshift is the first downshift (for example, 2 → 1 downshift), as shown by the two-dot chain line of the input torque Ti, the requested power on during coasting is turned on. The torque limit control of the engine 12 is executed until the inertia phase end time (time t3) in the downshift, and the input torque Ti is limited to a predetermined torque limit value or less.

  By the way, since the vehicle speed V is rapidly decreased during the deceleration traveling in the inertia traveling state due to the wheel brake being operated, the requested second downshift (for example, 3 → 2 downshift) is performed. The first downshift may be required before execution is complete. In such a case, if the second downshift has not progressed (for example, if the torque phase or the like has not started), the execution of the second downshift is stopped, and before the second downshift. It is conceivable to perform a jump downshift (for example, 3 → 1 downshift) from the gear stage to the gear stage after the first downshift. On the other hand, if the second downshift is in progress, the execution of the first downshift is delayed until the execution of the second downshift is completed, and the second downshift is completed after the second downshift is completed. It is conceivable to start executing the first downshift. Alternatively, when the gear stage formed by the first downshift is a gear stage for which shifting is prohibited during execution of the second downshift, execution of the second downshift is completed. It is conceivable to delay the execution of the first downshift until it is.

  When the execution of the first downshift is delayed until the execution of the second downshift is completed, when the coasting state is switched to the acceleration state, the second downshift is requested when coasting. It is executed by a power-on downshift, and after the second downshift is completed, the execution of the first downshift is started by a coast-time required power-on downshift. When the second downshift is performed by a coast required power-on downshift, the torque limit control of the engine 12 is not executed, and therefore an input torque Ti corresponding to the accelerator opening θacc is obtained. Therefore, it is assumed that the input torque Ti exceeds the predetermined torque limit value at the time when the execution of the first downshift is started by the coast required power-on downshift. When the first downshift is performed by a coast required power-on downshift, torque limit control of the engine 12 is executed. Then, when the first downshift is executed, the input torque Ti suddenly changes toward the predetermined torque limit value by executing the torque limit control, and a shock (for example, a feeling of stall due to a sudden decrease in drive torque) may occur.

  Therefore, when the electronic control unit 70 performs the delayed first downshift by the coast required power-on downshift, or the input torque Ti at the start of the torque limit control exceeds the predetermined torque limit value. In this case, the smoothing process is performed on the change speed of the input torque Ti in the torque limit control.

  The electronic control unit 70 further includes control state determination means, that is, a control state determination unit 76 in order to realize control for performing the smoothing process on the change speed of the input torque Ti in the torque limit control as described above. .

  The power source controller 72 delays execution of the first downshift requested next to the second downshift until the second downshift is completed during deceleration traveling in the inertial traveling state. When the first downshift is performed at the requested power-on downshift required during the transition, or when the input torque Ti at the start of the torque limit control exceeds a predetermined torque limit value, In the torque limit control, a smoothing process is performed to moderate the torque change rate when the input torque Ti is set to a predetermined torque limit value or less. This smoothing process of the input torque Ti is to change the input torque Ti abruptly (suddenly drop) at a torque change speed of the maximum input torque Ti that can be maximized by engine output control such as retard control, fuel suppression control, and throttle control, for example. On the other hand, the torque change rate of the input torque Ti is moderated and the input torque Ti is slowly lowered toward the predetermined torque limit value.

  Specifically, the control state determination unit 76 determines whether or not the vehicle speed V is equal to or lower than a predetermined vehicle speed. This determination is to determine whether the currently executed downshift is a coast downshift or a downshift requested by an accelerator operation. That is, since the coast downshift required by the vehicle speed V reduction is a shift on the low vehicle speed side compared to the downshift required by the accelerator operation, it is determined whether or not the vehicle is below a predetermined vehicle speed. It is to determine whether or not the coast downshift is less than the required vehicle speed V. Alternatively, the predetermined vehicle speed is determined in advance to determine that the vehicle speed V requires execution of torque limit control in order to suppress or prevent blowing of the AT input rotational speed Ni during the coast required power-on downshift. Is the threshold value.

  When it is determined that the vehicle speed V is equal to or lower than the predetermined vehicle speed, the control state determination unit 76 determines whether or not the currently executed control (downshift) is a power-on downshift and whether or not the accelerator is on. Determine based on. That is, the control state determination unit 76 determines whether or not the currently executed downshift is a coast-time required power-on downshift after a coast downshift request.

  When the control state determination unit 76 determines that the currently executed downshift is a coast-time required power-on downshift after a coast downshift request, the coast downshift is a downshift in which torque limit control is executed. It is determined whether or not the speed change pattern is. That is, the control state determination unit 76 determines whether or not the downshift is the first downshift.

  When the control state determination unit 76 determines that the coast downshift is a shift pattern in which torque limit control is executed (that is, when it is determined that the downshift is the first downshift), the torque is reduced. It is determined whether or not the input torque Ti at the start of the limit control exceeds a predetermined torque limit value. The control state determination unit 76 calculates the input torque Ti (= Te × torque ratio t of the torque converter 20) based on the estimated value of the engine torque Te. The control state determination unit 76 calculates the estimated value of the engine torque Te by applying the engine rotational speed Ne and the throttle valve opening θth to a predetermined known engine torque map. Further, determining whether or not the input torque Ti at the start of the torque limit control exceeds a predetermined torque limit value is that the execution of the first downshift requested after the request for the second downshift is performed. It is to determine whether or not it is delayed.

  When the control state determination unit 76 determines that the input torque Ti does not exceed the predetermined torque limit value, the power source control unit 72 determines that the first downshift is performed when the coast required power on When executed in a downshift, torque limit control is executed without performing an input torque Ti smoothing process at the start. On the other hand, when the control state determination unit 76 determines that the input torque Ti exceeds the predetermined torque limit value, the power source control unit 72 determines that the first downshift is coasted by the shift control unit 74. When executed in the required power-on downshift, torque limit control is executed while the input torque Ti is smoothed at the start. Since this torque limit control is executed when the coast downshift is performed by a coast required power-on downshift, this torque limit control is also referred to as reacceleration torque limit control.

  FIG. 5 shows a control operation for suppressing a shock caused by a sudden change in the input torque Ti of the automatic transmission 22 when the torque limiting control is performed at the time of a required power-on downshift of the electronic control device 70. It is a flowchart to be described, and is repeatedly executed, for example, during the output of a downshift command for the automatic transmission 22. FIG. 6 is a diagram showing an example of a time chart when the control operation shown in the flowchart of FIG. 5 is executed.

  In FIG. 5, first, in step (hereinafter, step is omitted) S10 corresponding to the function of the control state determination unit 76, it is determined whether or not the vehicle speed V is equal to or lower than a predetermined vehicle speed. If the determination at S10 is negative, this routine is terminated. If the determination in S10 is affirmative, in S20 corresponding to the function of the control state determination unit 76, whether or not the currently executed control (downshift) is a power-on downshift (that is, the currently executed downshift). Is a coast-time required power-on downshift after a coast downshift request. If the determination at S20 is negative, this routine is terminated. If the determination in S20 is affirmative, in S30 corresponding to the function of the control state determination unit 76, the coast downshift is a shift pattern that becomes a downshift (the first downshift) in which torque limit control is executed. It is determined whether or not. If the determination at S30 is negative, this routine is terminated. If the determination in S30 is affirmative, it is determined in S40 corresponding to the function of the control state determination unit 76 whether or not the input torque Ti at the start of the torque limit control exceeds a predetermined torque limit value. If the determination in S40 is negative, in S50 corresponding to the function of the power source control unit 72, when the first downshift is executed in the coast required power-on downshift, the input torque Ti at the start is started. The reacceleration torque limit control is executed without performing the annealing process. If the determination in S40 is affirmative, in S60 corresponding to the function of the power source control unit 72, when the first downshift is executed as a coast-time required power-on downshift, the input torque Ti is started at the start. The reacceleration torque limit control is executed while the annealing process is performed.

  FIG. 6 shows that the first downshift 2 → 1 downshift is required before the execution of the second downshift 3 → 2 downshift is completed during deceleration traveling in the inertial running state. An example of an embodiment in the case of being performed is shown. In FIG. 6, the output start of the shift command of the 2 → 1 coast downshift requested during the transition of the 3 → 2 coast downshift is delayed after the start of the output of the shift command of 3 → 2 coast downshift (see time t1). (Refer to the broken line of the gear stage at time t2−time t4). If the accelerator is turned on during this delay and the coasting state is switched from the coasting state to the acceleration state (see after t3), the 3 → 2 coast downshift is executed by the coast required power on downshift. The When the 3 → 2 coast downshift is executed by the coast required power-on downshift, the torque limit control of the engine 12 is not executed, so the input torque Ti is increased to a torque value corresponding to the accelerator opening θacc ( t3 time point-t4 time point reference). After completion of execution of 3 → 2 coast downshift, output of shift command of 2 → 1 coast downshift is started, and execution of 2 → 1 coast downshift, which was delayed, is started by requested power-on downshift at coast (Refer to time t4). When the 2 → 1 coast downshift is executed by the coast required power-on downshift, the torque limit control of the engine 12 is executed until the inertia phase ends (see time t4−time t5). Since the input torque Ti exceeds the predetermined torque limit value at the start time of the torque limit control (see time t4), the input torque Ti is lowered to the predetermined torque limit value in the torque limit control here. At this time, as shown in the solid line in this embodiment, an annealing process is performed to moderate the rate of change of the input torque Ti. The broken line of the input torque is a comparative example in the case where the smoothing process of the input torque Ti is not performed. For example, the input torque that can be maximized by engine output control such as retard control, fuel suppression control, and throttle control. This is an example in which the input torque Ti is suddenly changed (rapidly lowered) at the torque change speed of Ti.

  As described above, according to the present embodiment, in accordance with the switching from the inertia traveling state to the acceleration traveling state while the execution of the first downshift requested during the deceleration traveling in the inertia traveling state is delayed. In the requested coast-time required power-on downshift, the second downshift requested before the first downshift is executed, so that the torque limit control at the start of the first downshift is started. When it is assumed that the input torque Ti of the automatic transmission 22 exceeds the predetermined torque limit value, or it is specified that the input torque Ti at the start of the torque limit control exceeds the predetermined torque limit value. In this case, since the smoothing process is performed to moderate the torque change speed when the input torque Ti is set to be equal to or less than the predetermined torque limit value in the torque limit control, the input torque Ti is set to the predetermined torque. It is gradually changed toward the limit value. Therefore, when the torque limit control is performed at the time of the coast required power on downshift, it is possible to suppress the shock accompanying the sudden change of the input torque Ti of the automatic transmission 22.

  In addition, according to the present embodiment, the first downshift is performed by a coast-time required power-on downshift, except that the first downshift is a coast downshift that is requested in the coasting state. Even if the first downshift is a downshift requested by the accelerator operation, the torque limit control is not executed even if the requested power-on downshift during coasting, and the desired drive is performed. Torque is easily obtained.

  As mentioned above, although the Example of this invention was described in detail based on drawing, this invention is applied also in another aspect.

  For example, in the flowchart of FIG. 5 in the above-described embodiment, it is determined in S40 whether or not the input torque Ti at the start of torque limit control exceeds a predetermined torque limit value. It may be determined whether execution of the requested first downshift following the request is delayed. Thus, the flowchart of FIG. 5 can be changed as appropriate.

  In the above-described embodiment, the 2 → 1 downshift is exemplified as the first downshift when the torque limit control of the engine 12 is executed when the coast downshift is performed by the coast required power-on downshift. However, it is not limited to this mode. The first downshift may be a 2 → 1 downshift or a 3 → 2 downshift, or may be a 2 → 1 downshift or a 2 → 1 downshift and a 3 → 2 downshift based on some condition. It may be a shift. If the first downshift is a 2 → 1 downshift and a 3 → 2 downshift, the second downshift is a 4 → 3 downshift or the like.

  In the above-described embodiment, the automatic transmission 22 is formed with eight forward gears, but is not limited to this mode. The automatic transmission 22 may be a stepped transmission in which a plurality of gear stages having different gear ratios are selectively formed. The automatic transmission may be a planetary gear type automatic transmission such as the automatic transmission 22, or a synchronous mesh type parallel two-shaft automatic transmission, or a synchronous mesh type parallel two-shaft automatic transmission. In addition, a known automatic transmission such as a DCT (Dual Clutch Transmission) or continuously variable transmission having two input shafts may be used. In short, the present invention can be applied to any automatic transmission that transmits power from a power source.

  Moreover, although the engine 12 was illustrated as a power source of the vehicle 10 in the above-mentioned Example, it is not restricted to this aspect. For example, as the power source, another prime mover such as an electric motor can be used alone or in combination with the engine 12. Further, the power of the engine 12 is transmitted to the automatic transmission 22 via the torque converter 20, but this is not restrictive. For example, instead of the torque converter 20, another fluid transmission device such as a fluid coupling (fluid coupling) having no torque amplification action may be used. Alternatively, this fluid transmission device is not necessarily provided.

  The above description is only an embodiment, and the present invention can be implemented in variously modified and improved forms based on the knowledge of those skilled in the art.

10: Vehicle 12: Engine (power source)
22: Automatic transmission 70: Electronic control device (control device)
72: Power source control unit

Claims (2)

A control device for a vehicle including an automatic transmission for transmitting power from a power source,
The input torque of the automatic transmission when the first downshift of the automatic transmission is performed by a power-on downshift of the automatic transmission that is required as a result of switching from the inertia running state to the accelerated running state Including a power source control unit that executes torque limit control of the power source so as to limit the torque to a predetermined torque limit value or less,
The power source control unit is requested after the second downshift requested after the second downshift required on the higher vehicle speed side than the first downshift of the automatic transmission during the deceleration traveling in the inertia traveling state. Execution of the first downshift is delayed until the second downshift is completed, or when the first downshift is performed at the requested power-on downshift during the transition, or the torque When the input torque at the start of the limit control exceeds the predetermined torque limit value, a smoothing process for gradually reducing the torque change speed when the input torque is set to be equal to or less than the predetermined torque limit value in the torque limit control A control device for a vehicle, characterized in that   The power source control unit is configured such that the first downshift is performed in the power-on downshift except that the first downshift is a coast downshift requested in the coasting state. 2. The vehicle control device according to claim 1, wherein the torque limit control is not executed.

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