JP2018017121A - Control device of vehicle - Google Patents

Abstract

An object of the present invention is to provide a vehicle control device capable of realizing a driving force characteristic with high responsiveness while suppressing an increase in input shaft rotational speed by torque down control during a power-on downshift. During execution of torque-down control during a power-on downshift (ST13), when a start condition for torque-down return control is satisfied (YES in ST14), a target set in torque phase control is set. Torque down return control is executed to decrease the torque down amount at a return rate corresponding to the torque phase time (ST15). As a result, the reduction ratio of the torque reduction amount can be set to an appropriate value that is linked to the shift state of the automatic transmission, and a driving force characteristic with high responsiveness can be realized. [Selection] Figure 6

Description

  The present invention relates to a vehicle control device equipped with a driving force source and an automatic transmission. In particular, the present invention relates to torque-down control of a driving force source that is executed during a power-on downshift.

  2. Description of the Related Art Conventionally, in a vehicle equipped with an engine and a stepped automatic transmission, torque down control for reducing engine torque is performed during power-on downshift. An example of this torque down control is to retard the ignition timing of the spark plug (ignition retard).

  Patent Document 1 discloses that an ignition delay amount in torque-down control is returned at a predetermined rate (Patent Document 1 is designed to eliminate ignition timing delay).

JP-A-4-262165

  However, the return of the ignition retard amount disclosed in Patent Document 1 is performed during the transition period from the inertia phase to the torque phase. For this reason, it is difficult to achieve desired driving force characteristics over the entire period of the torque phase while suppressing the increase of the input shaft rotation speed (the increase in rotation synchronization) by torque down control. . For example, when the torque return gradient in the torque down control is small and the torque down amount is more than the amount necessary and sufficient for suppressing the increase in the input shaft rotation speed, the response of the driving force is lowered. It will be. For this reason, there is room for improvement in the return of torque in the torque down control.

  The present invention has been made in view of the above points, and the object of the present invention is to provide a highly responsive operation while suppressing the rising of the input shaft rotational speed by torque down control during power-on downshift. An object of the present invention is to provide a vehicle control device capable of realizing driving force characteristics.

  In order to achieve the above object, a solution means of the present invention includes a stepped automatic transmission that establishes one of a plurality of shift stages by selectively engaging a plurality of friction engagement elements. A control device applied to a vehicle equipped with a driving force source that outputs torque toward the input shaft of the automatic transmission is assumed. When the torque-down control of the driving force source started near the synchronous rotational speed of the power-on downshift of the automatic transmission, the control device performs the power-on downshift at the end of the torque-down control. And a torque return control unit that reduces the torque reduction amount at a return rate corresponding to the torque phase control execution time.

  With this specific matter, the torque reduction amount reduction rate (for example, the amount of torque reduction amount per unit time) at the time of terminating the torque reduction control while suppressing the increase of the input shaft rotation speed by the torque reduction control is set. Therefore, it can be set to an appropriate one linked to the shift state of the automatic transmission, and it is possible to realize a driving force characteristic with high responsiveness.

  In the present invention, at the time of torque down control of the driving force source during the power-on downshift of the automatic transmission, at the end of the torquedown control, the return ratio according to the torque phase control execution time of the power-on downshift The amount of torque reduction is reduced. As a result, it is possible to realize a driving force characteristic with high responsiveness while suppressing an increase in the input shaft rotation speed by the torque down control.

It is a figure showing a schematic structure of a drive system of a vehicle concerning an embodiment. It is a skeleton figure which shows the structure of a torque converter and an automatic transmission. 4 is an engagement table showing engagement states of the first to fourth clutches, the first brake, and the second brake for each shift stage in the automatic transmission. It is a block diagram which shows the structure of the control system of a vehicle. It is a flowchart figure for demonstrating the procedure of the torque phase control which concerns on embodiment. It is a flowchart figure for demonstrating the procedure of the torque down control which concerns on embodiment.

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

  First, a vehicle 100 according to the present embodiment will be described with reference to FIGS.

  As shown in FIG. 1, the vehicle 100 includes an engine 1, a torque converter 2, a stepped automatic transmission 3, a hydraulic control device 4, and an ECU 5. The vehicle 100 is, for example, an FF (front engine / front drive) system, and the output of the engine 1 is transmitted to the differential device 6 via the torque converter 2 and the automatic transmission 3, and left and right drive wheels (front wheels) 7. To be distributed.

-Engine-
The engine (internal combustion engine) 1 is a driving force source for traveling, for example, a multi-cylinder gasoline engine. The engine 1 is configured such that its operating state can be controlled by the throttle valve opening (intake air amount), fuel injection amount, ignition timing, and the like.

-Torque converter-
As shown in FIG. 2, the torque converter 2 includes a pump impeller 21 connected to a crankshaft 1a that is an output shaft of the engine 1, a turbine runner 22 connected to the automatic transmission 3, and a stator having a torque amplification function. 23, and a lockup clutch 24 for directly connecting the engine 1 and the automatic transmission 3 to each other. In FIG. 2, the lower half is omitted and only the upper half is schematically shown with respect to the rotation center axes of the torque converter 2 and the automatic transmission 3.

-Automatic transmission-
The automatic transmission 3 is provided in a power transmission path between the engine 1 and the drive wheels 7, and is configured to shift the rotation of the input shaft 3a and output it to the output shaft 3b. In the automatic transmission 3, the input shaft 3 a is connected to the turbine runner 22 of the torque converter 2, and the output shaft 3 b is connected to the drive wheels 7 via the differential device 6 and the like.

  The automatic transmission 3 includes a first transmission unit (front planetary) 31 mainly composed of a first planetary gear unit 31a, a second planetary gear unit 32a, and a second planetary gear unit 32b. A transmission unit (rear planetary) 32, a first clutch C1 to a fourth clutch C4, a first brake B1, a second brake B2, and the like are configured.

  The first planetary gear device 31a constituting the first transmission unit 31 is a double pinion type planetary gear mechanism, and supports a sun gear S1, a plurality of pairs of pinion gears P1 meshing with each other, and the pinion gears P1 so as to be able to rotate and revolve. Planetary carrier CA1 and ring gear R1 meshing with sun gear S1 via pinion gear P1.

  The planetary carrier CA1 is coupled to the input shaft 3a and rotates integrally with the input shaft 3a. The sun gear S1 is fixed to the transmission case 30 and cannot rotate. The ring gear R1 functions as an intermediate output member, is decelerated with respect to the input shaft 3a, and transmits the decelerated rotation to the second transmission unit 32.

  The second planetary gear unit 32a constituting the second transmission unit 32 is a single pinion type planetary gear mechanism, which is a sun gear S2, a pinion gear P2, and a planetary carrier RCA that supports the pinion gear P2 so as to be capable of rotating and revolving. And a ring gear RR that meshes with the sun gear S2 via the pinion gear P2.

  The third planetary gear device 32b constituting the second transmission unit 32 is a double pinion type planetary gear mechanism, and includes a sun gear S3, a plurality of pairs of pinion gears P2 and P3 meshing with each other, and the pinion gears P2 and P3. A planetary carrier RCA that supports rotation and revolution is provided, and a ring gear RR that meshes with the sun gear S3 via pinion gears P2 and P3. The planetary carrier RCA and the ring gear RR are shared by the second planetary gear device 32a and the third planetary gear device 32b.

  The sun gear S2 is selectively connected to the transmission case 30 by the first brake B1. The sun gear S2 is selectively connected to the ring gear R1 via the third clutch C3. Further, the sun gear S2 is selectively coupled to the planetary carrier CA1 via the fourth clutch C4. Sun gear S3 is selectively coupled to ring gear R1 via first clutch C1. The planetary carrier RCA is selectively coupled to the transmission case 30 by the second brake B2. Further, the planetary carrier RCA is selectively coupled to the input shaft 3a via the second clutch C2. The ring gear RR is connected to the output shaft 3b and rotates integrally with the output shaft 3b.

  The first clutch C1 to the fourth clutch C4, the first brake B1, and the second brake B2 are all friction engagement elements that are frictionally engaged by a hydraulic actuator, and are controlled by the hydraulic control device 4 and the ECU 5.

  FIG. 3 is an engagement table showing an engaged state or a released state of the first clutch C1 to the fourth clutch C4, the first brake B1, and the second brake B2 for each shift speed (gear speed). In the engagement table of FIG. 3, a circle indicates an “engaged state”, and a blank indicates a “released state”.

  As shown in FIG. 3, in the automatic transmission 3 of this example, the first clutch C1 and the second brake B2 are engaged, so that the gear ratio (the rotational speed of the input shaft 3a / the rotational speed of the output shaft 3b). The first shift speed (1st) with the largest value is established. The second gear (2nd) is established by engaging the first clutch C1 and the first brake B1.

  The third shift stage (3rd) is established by engaging the first clutch C1 and the third clutch C3, and the fourth shift stage (4th) by engaging the first clutch C1 and the fourth clutch C4. Is established. The fifth gear (5th) is established by engaging the first clutch C1 and the second clutch C2, and the sixth gear (6th) by engaging the second clutch C2 and the fourth clutch C4. Is established. The seventh shift stage (7th) is established by engaging the second clutch C2 and the third clutch C3, and the eighth shift stage (8th) by engaging the second clutch C2 and the first brake B1. Is established. The reverse speed (Rev) is established when the third clutch C3 and the second brake B2 are engaged.

  As described above, the automatic transmission 3 is configured to establish one of the plurality of shift stages by selectively engaging the plurality of friction engagement elements.

-Hydraulic control device-
The hydraulic control device 4 is provided to control the state (engaged state or released state) of the friction engagement element of the automatic transmission 3. The hydraulic control device 4 also has a function of controlling the lockup clutch 24 of the torque converter 2.

-ECU-
The ECU 5 is configured to perform operation control of the engine 1 and shift control of the automatic transmission 3. Specifically, as shown in FIG. 4, the ECU 5 includes a CPU 51, a ROM 52, a RAM 53, a backup RAM 54, an input interface 55, and an output interface 56. The ECU 5 is an example of the “control device” in the present invention.

  The CPU 51 executes arithmetic processing based on various control programs and maps stored in the ROM 52. The ROM 52 stores various control programs, maps that are referred to when the various control programs are executed, and the like. The RAM 53 is a memory that temporarily stores a calculation result by the CPU 51, a detection result of each sensor, and the like. The backup RAM 54 is a non-volatile memory that stores data to be stored when the ignition is turned off.

  A crank position sensor 81, an input shaft rotational speed sensor 82, an output shaft rotational speed sensor 83, an accelerator opening sensor 84, a throttle opening sensor 85, and the like are connected to the input interface 55.

  The crank position sensor 81 is provided for calculating the rotational speed of the engine 1. The input shaft rotational speed sensor 82 is provided for calculating the rotational speed of the input shaft 3a of the automatic transmission 3 (input shaft rotational speed; turbine rotational speed). The output shaft rotation speed sensor 83 is provided for calculating the rotation speed (output shaft rotation speed) of the output shaft 3 b of the automatic transmission 3. It is possible to calculate the vehicle speed from the output shaft rotation speed. The accelerator opening sensor 84 is provided to detect an accelerator opening that is an accelerator pedal depression amount (operation amount). The throttle opening sensor 85 is provided for detecting the throttle opening of the throttle valve.

  To the output interface 56, an injector 91, an igniter 92, a throttle motor 93, the hydraulic control device 4, and the like are connected. The injector 91 is a fuel injection valve and can adjust the fuel injection amount. The igniter 92 is provided for adjusting the ignition timing by the ignition plug. The throttle motor 93 is provided to adjust the throttle opening of the throttle valve.

  The ECU 5 is configured to be able to control the operating state of the engine 1 by controlling the throttle opening, the fuel injection amount, the ignition timing, and the like based on the detection result of each sensor. Further, the ECU 5 is configured to be able to execute shift control of the automatic transmission 3 and control of the lock-up clutch 24 of the torque converter 2 by controlling the hydraulic control device 4.

  In the shift control by the ECU 5, for example, the target shift speed is set based on a shift map using the vehicle speed and the accelerator opening as parameters, and the hydraulic control device 4 is controlled so that the actual shift speed becomes the target shift speed.

-Shift control using a shift model-
Before explaining the characteristic control (torque down control) in this embodiment, an outline of the shift control for determining the control operation amount for realizing the shift target value in the automatic transmission 3 will be described.

  As a general shift control, for example, whether or not a shift shock, a shift time, and the like are appropriate in an actual vehicle while evaluating whether or not each friction engagement element at the time of a shift is based on a control map predetermined by adaptation. There is a method of determining a torque capacity (or hydraulic pressure command value) and executing a shift. In the method using the control map, a shift pattern such as a power-on downshift (hereinafter sometimes simply referred to as a power-on downshift) or a power-off upshift (hereinafter also simply referred to as a power-off upshift) is used. A large number of control maps need to be created in accordance with the combination of shift speeds before and after the shift. For this reason, the greater the number of shift stages of the automatic transmission, the more labor is required for the adaptation work.

  Therefore, in the present embodiment, as a shift control, a method of executing a shift using a shift model that determines a control operation amount for realizing a shift target value is employed instead of the method using the control map. The shift target value is a target value of an element (for example, shift time, driving force, etc.) that determines a change mode to be realized at the time of shifting. The control operation amount is a required value of an element (engine torque, clutch torque, etc.) operated with respect to a control target.

  Hereinafter, the shift control using the shift model will be described. The equation of motion during the shift is expressed by the following equations (1) and (2).

  These expressions (1) and (2) are derived from the equations of motion for the mutually connected rotating elements constituting the automatic transmission 3 and the relational expressions in the planetary gear device constituting the automatic transmission 3. It is a thing. The equation of motion for each rotating element is a torque expressed by the product of the inertia in each rotating element and the rate of change in rotational speed with time, among the three members of the planetary gear unit and the members on both sides of the friction engagement element. The equation of motion is defined by the torque acting on the members involved in each rotating element. Further, the relational expression in the planetary gear unit is a relational expression that defines the relationship between the torque and the rate of change in the rotational speed time in the three members of the planetary gear unit using the gear ratio of the planetary gear unit.

  In the formulas (1) and (2), dωt / dt is a time derivative of the turbine rotational speed (rotational angular speed) ωt (that is, the input shaft rotational speed ωi), that is, a time change rate, and the rotational member of the input shaft 3a side. It represents the acceleration of the input shaft 3a (angular acceleration, hereinafter referred to as input shaft acceleration) as a speed change amount. dωo / dt is the time change rate of the output shaft rotation speed ωo, and represents the output shaft acceleration. Tt represents turbine torque that is torque on the input shaft 3a as torque on the rotating member on the input shaft 3a side, that is, transmission input torque Ti. The turbine torque Tt agrees with the engine torque Te (= Tt / t) when the torque ratio t of the torque converter 2 is taken into consideration. To represents transmission output torque that is torque on the output shaft 3b as torque on the rotating member on the output shaft 3b side. Tcapl is a torque capacity (hereinafter referred to as an engagement-side clutch torque) of a friction engagement element that performs an engagement operation at the time of shifting. Tcdrn is the torque capacity of the friction engagement element that performs the releasing operation at the time of shifting (hereinafter referred to as the release side clutch torque). a1, a2, b1, b2, c1, c2, d1, and d2 are constants when the equations (1) and (2) are derived, and the inertia and the planetary gears in each of the rotating elements It is a coefficient determined by design from the gear ratio of the device. The specific numerical value of this constant varies depending on, for example, the type of shift (for example, a shift pattern or a combination of shift stages before and after the shift). Therefore, although the above-mentioned equation of motion is one predetermined equation, the equation of motion corresponding to each type of shift, which is a constant different for each type of shift, is used for the shift of the automatic transmission 3.

  The equations (1) and (2) are gear train motion equations of the automatic transmission 3 in which the relationship between the shift target value and the control operation amount is formulated. The shift target value can express each target value of the shift time and the driving force and can be handled on the gear train motion equation. In the present embodiment, the input shaft acceleration dωt / dt is used as an example of a physical quantity that can express the shift time. Further, the transmission output torque To is used as an example of a physical quantity that can express the driving force. That is, in this embodiment, the shift target value is set with two values of the input shaft acceleration dωt / dt and the transmission output torque To.

  On the other hand, in the present embodiment, the control operation amount for establishing the shift target value is represented by three values of the turbine torque Tt (the engine torque Te is also agreed), the engagement side clutch torque Tcapl, and the release side clutch torque Tcdrn. It is set. Then, since there are three control operation amounts for the equation of motion being composed of the above two formulas (1) and (2), the control operation amount for establishing the two shift target values is uniquely solved. It is not possible. The output shaft acceleration dωo / dt in each equation is calculated from the output shaft rotation speed ωo that is a detection value of the output shaft rotation speed sensor 83.

  Therefore, a study was made to add a constraint condition to the equations of motion of the equations (1) and (2) to uniquely solve the control operation amount. In this embodiment, it is suitable for expressing and controlling the transfer of torque during a shift, and as a restraint condition that can correspond to any shift pattern, it is engaged with a disengagement clutch. The torque sharing rate of the transmission torque that is handled by the side clutch is used. That is, the torque sharing rate of the transmission torque that can incorporate the torque transfer during the shift into the equation of motion and uniquely solve the control operation amount is set as the constraint condition. The torque sharing ratio is the total transmission torque (total transmission torque) that must be handled by the disengagement side clutch and the engagement side clutch when shifting the automatic transmission 3, for example, torque on the input shaft 3a (total on the input shaft) (Transmission torque) is the ratio of the transmission torque shared by both friction engagement elements to the total transmission torque on the input shaft. In this embodiment, the torque sharing rate of the engagement side clutch is set to “xapl”, the torque sharing rate of the release side clutch is set to “xdrn”, and each torque sharing rate reflects the transfer of torque during shifting. Using the torque sharing ratio x (for example, 0 ≦ x ≦ 1) that changes in time series, the following equations (3) and (4) are defined.

xapl = x (3)
xdrn = 1-x (4)
The relational expression between the engagement-side clutch torque Tcapl and the disengagement-side clutch torque Tcdrn is based on “Tcapl” and “Tcdrn” replaced with the torque on the input shaft 3a, and the expressions (3) and (4). , “X” (= xapl) and “1-x” (= xdrn). Then, from the equation (1), the equation (2), and the relational expression between “Tcapl” and “Tcdrn”, the turbine operation torque Tt, the engagement side clutch torque Tcapl, and the disengagement side, which are control operation amounts, are obtained. A relational expression for calculating the clutch torque Tcdrn is derived. The turbine torque Tt (the engine torque Te is also agreed) is a relational expression using “x” (= xapl), “1-x” (= xdrn), input shaft acceleration dωt / dt, transmission output torque To, and the like. It is represented by Similarly, the engagement side clutch torque Tcapl is expressed by a relational expression using “x” (= xapl), input shaft acceleration dωt / dt, transmission output torque To, and the like. Similarly, the release side clutch torque Tcdrn is represented by a relational expression using “1-x” (= xdrn), input shaft acceleration dωt / dt, transmission output torque To, and the like.

  That is, the speed change model of the present embodiment has a relation between the equation of motion (the above formulas (1) and (2)) of the automatic transmission 3 including the shift target value and the control operation amount, and the torque sharing rate ( The control operation amount is calculated based on the shift target value using the equations (3) and (4)). As described above, in this embodiment, the shift of the automatic transmission 3 is executed using the shift model by adding the constraint condition set by the torque sharing ratio x to the equations (1) and (2). . Therefore, even if there are three control operation amounts for two shift target values, the three control operation amounts can be appropriately determined using the shift model. This shift model is one predetermined model. However, as described above, since the gear train equation of motion, which is a constant different for each type of shift (for example, a combination of shift patterns and shift stages before and after the shift), is used, For the speed change of the transmission 3, a speed change model corresponding to each type of speed change is used.

-Torque down control-
Next, torque down control, which is a feature of this embodiment, will be described.

  This torque-down control is to reduce the engine output torque when the input shaft rotational speed reaches near the synchronous rotational speed of the target gear stage (hereinafter referred to as the target gear stage) during power-on downshift. As a result, the input shaft rotation speed increases (the increase due to the release of the frictional engagement element on the release side) and the shift shock (the shift caused by the increase in the torque capacity of each frictional engagement element). This is to suppress shock). As an example of this torque down control, the ignition timing of the spark plug is shifted to the retard side (ignition retard). Another example is torque down control by reducing the intake air amount.

  This torque-down control is a torque phase control (when the input shaft rotational speed reaches the vicinity of the synchronous rotational speed of the target shift stage) when the target shift stage is established (the release side frictional engagement element and the engagement side frictional engagement). This is performed when control for switching to a combination element is performed.

  The return of the ignition retard amount in the torque down control disclosed in Patent Document 1 as a prior art is performed during the transition period from the inertia phase to the torque phase. For this reason, it is difficult to realize a desired driving force characteristic in the entire period of the torque phase while suppressing the rising of the input shaft rotational speed by the torque down control.

  In this embodiment, in view of this point, at the time of power-on downshift, it is possible to realize a driving force characteristic with high responsiveness while suppressing the increase of the input shaft rotation speed by torque down control. It is.

  Specifically, in the present embodiment, when the torque down control of the engine (driving force source) 1 that starts near the synchronous rotational speed of the power-on downshift of the automatic transmission 3 is performed, The torque-down amount is decreased at a return rate corresponding to the torque phase control execution time of the power-on downshift.

  This torque down control is executed by the ECU 5. For this reason, in ECU5, the functional part which performs the said torque down control is comprised as a torque return control part said by this invention.

  Next, the procedure of torque down control in this embodiment will be described. Since this torque-down control is performed when the torque phase control of the automatic transmission 3 is performed, the torque phase control procedure is first described along the flowchart of FIG. 5, and then the flowchart of FIG. The procedure of torque-down control will be described along These flowcharts are repeatedly executed every predetermined time after the start switch of the vehicle is turned on.

  In step ST1 in FIG. 5 (torque phase control), a shift request for the automatic transmission 3 is generated, and it is determined whether the shift request is a power-on downshift request. That is, it is determined whether or not the target shift speed set based on the shift map as the accelerator pedal is depressed is a shift speed on the low gear side with respect to the current shift speed.

  If a power-on downshift request is not generated, that is, if the shift request for the automatic transmission 3 is an upshift request, or if no shift request for the automatic transmission 3 is generated, NO is determined in step ST1. Returned as is. In this case, if an upshift request is generated, a shift according to the shift request is executed.

  On the other hand, if a power-on downshift request has occurred and YES is determined in step ST1, the process proceeds to step ST2 to determine whether or not the torque phase control start condition is satisfied. Specifically, since the torque phase control is started when the input shaft rotational speed reaches the vicinity of the synchronous rotational speed of the target gear stage in the current power-on downshift request, in this step ST2, the input shaft rotational speed is controlled. It is determined whether or not the rotational speed has reached the vicinity of the synchronous rotational speed of the target shift stage. In other words, a shift from the shift stage before the start of the shift to the target shift stage is started, and it is determined whether or not the input shaft rotational speed has reached the vicinity of the synchronous rotational speed of the target shift stage as this shift proceeds . For example, it is determined whether or not the input shaft rotational speed has reached within a predetermined deviation from the synchronous rotational speed of the target shift stage. Here, since the downshift toward the target gear stage is performed, it is determined whether the input shaft rotational speed is lower than the synchronous rotational speed of the target gear stage, and the difference has reached within a predetermined deviation. It will be judged. The deviation serving as the threshold is set by experiment or simulation.

  If the torque phase control start condition is not satisfied and NO is determined in step ST2, the process returns as it is. That is, it is returned as it is because it is not yet the timing to start the torque phase control. That is, it waits for the torque phase control start condition to be satisfied (the input shaft rotational speed reaches the vicinity of the synchronous rotational speed of the target gear stage) during the period when the power-on downshift request is generated.

  On the other hand, if the torque phase control start condition is satisfied and YES is determined in step ST2, the process proceeds to step ST3, where the target torque phase time is set. This target torque phase time is set based on parameters (accelerator opening, vehicle speed, etc.) indicating the driver's required driving force, and is set by experiment or simulation and is mapped to the ROM (target torque phase time). Map). That is, in step ST3, the target torque phase time is read from the target torque phase time map, and the target torque phase time is set.

  Then, it moves to step ST4 and torque phase control is performed. That is, the hydraulic pressure supplied to and discharged from the friction engagement element is controlled so that the target torque phase time set in step ST3 is obtained. Specifically, the disengagement-side clutch torque Tcdrn and the engagement-side clutch torque Tcapl are calculated using the equations (1) and (2) so that the target torque phase time can be obtained.

  In this way, the target torque phase time is set and torque phase control is performed. When the switching between the disengagement side friction engagement element and the engagement side friction engagement element is completed, the current shift (power-on downshift) is completed. Shift) ends.

  Next, the torque down control in this embodiment will be described along the flowchart of FIG.

  First, in step ST11, it is determined whether or not a shift request for the automatic transmission 3 is generated, and the shift request is a power-on downshift request. That is, it is determined whether or not the target shift speed set based on the shift map as the accelerator pedal is depressed is a shift speed on the low gear side with respect to the current shift speed.

  If the power-on downshift request is not generated, that is, if the shift request of the automatic transmission 3 is an upshift request or if the shift request of the automatic transmission 3 is not generated, NO determination is made in step ST11. Returned as is. In this case, as described above, if an upshift request is generated, a shift according to the shift request is executed.

  On the other hand, if a power-on downshift request has occurred, and if YES is determined in step ST11, the process proceeds to step ST12, where is the start condition for the torque down control executed when the input shaft rotation speed is synchronized established? Determine whether or not. Specifically, the torque down control is started when the input shaft rotational speed reaches the vicinity of the synchronous rotational speed of the target shift stage in the current power-on downshift request. Therefore, in this step ST12, the input shaft rotational speed is controlled. It is determined whether or not the rotational speed has reached the vicinity of the synchronous rotational speed of the target shift stage. In other words, a shift from the shift stage before the start of the shift to the target shift stage is started, and it is determined whether or not the input shaft rotational speed has reached the vicinity of the synchronous rotational speed of the target shift stage by the progress of this shift. . For example, it is determined whether or not the input shaft rotational speed has reached within a predetermined deviation from the synchronous rotational speed of the target shift stage. Here, since the downshift toward the target gear stage is performed, it is determined whether the input shaft rotational speed is lower than the synchronous rotational speed of the target gear stage, and the difference has reached within a predetermined deviation. It will be judged. The deviation serving as the threshold is set by experiment or simulation. Further, the deviation serving as the threshold does not have to be the same as the deviation serving as the threshold in the torque phase control start condition (deviation used in the determination in step ST2).

  If the torque down control start condition is not satisfied and the determination in step ST12 is NO, the process directly returns. That is, it is returned as it is, assuming that it is not yet the timing to start the torque-down control. That is, it waits for the start condition of torque down control to be satisfied (the input shaft rotational speed reaches the vicinity of the synchronous rotational speed of the target gear stage) during the period when the power-on downshift request is generated.

  On the other hand, if the torque down control start condition is satisfied and YES is determined in step ST12, the process proceeds to step ST13, and the torque down control is executed. In other words, the engine output torque is reduced by shifting the ignition timing of the spark plug to the retard side, thereby suppressing the rising of the input shaft rotation speed and the shift shock.

  The torque-down amount (ignition timing retardation amount) in this torque-down control is such that the downshift is performed as quickly as possible while sufficiently suppressing the rise of the input shaft rotation speed and sufficiently suppressing the shift shock. Set as Specifically, a delay amount that is set in advance is stored in the ROM with the operating state such as the combination of the gears before and after the shift and the engine speed as a parameter, and the retard amount corresponding to the current operating state is stored. It will be extracted from the ROM.

  Further, this torque down control may be performed by reducing the intake air amount (decreasing the throttle valve opening).

  After the torque down control is executed, the process proceeds to step ST14, and it is determined whether or not the start condition of the torque down return control is satisfied. This condition is satisfied, for example, when the torque sharing rate of the frictional engagement element on the engagement side when the target shift speed is satisfied reaches a predetermined value. This condition is satisfied when the elapsed time from the start point of the power-on downshift shift (more specifically, the elapsed time since the start of the torque phase control) reaches a predetermined time. Also good.

  If the start condition of the torque down return control is not satisfied and the determination is NO in step ST14, the process returns to step ST13, and the torque down control is performed with the above-described retard amount (retard amount extracted from the ROM). Continue.

  If the start condition for torque down return control is satisfied and YES is determined in step ST14, the process proceeds to step ST15 to execute torque down return control. In this torque-down return control, the torque-down amount is gradually reduced at a return rate corresponding to the target torque phase time (torque phase control execution time) set in the torque phase control.

  In the ROM, a torque return ratio corresponding to the target torque phase time (in conjunction with the target torque phase time) is obtained by experiment or simulation so as to realize a highly responsive driving force characteristic. Has been. For example, information on the torque return ratio is stored so that a smaller value can be obtained as the torque return ratio as the target torque phase time is longer. That is, the longer the target torque phase time, the longer the execution time of the torque down return control.

  For this reason, in step ST15, torque return return control is executed in which information on the torque return rate corresponding to the target torque phase time is read from the ROM, and the torque down amount is gradually reduced at this return rate. become.

  By executing the torque-down return control in this way (by reducing the torque-down amount at the set return rate), a highly responsive driving force characteristic is realized.

  The operation of step ST15 described above is an operation by the torque return control unit referred to in the present invention, and in the torque down control of the driving force source started near the synchronous rotational speed of the power-on downshift of the automatic transmission, At the end of the torque-down control, this corresponds to an operation of reducing the torque-down amount at a return rate corresponding to the torque phase control execution time of the power-on downshift.

  The above operation is repeated every predetermined time.

  As described above, in the present embodiment, when the torque reduction control of the engine 1 during the power-on downshift shift of the automatic transmission 3 is performed, the torque phase control of the power-on downshift shift is executed at the end of the torque-down control. The torque-down amount is decreased at a return rate corresponding to time (target torque phase time). As a result, the rate of decrease in the torque-down amount when terminating the torque-down control is set to an appropriate one that is linked to the shift state of the automatic transmission 3 while suppressing the increase in the input shaft rotation speed by the torque-down control. It can be set, and it becomes possible to realize a driving force characteristic with high responsiveness.

(Other embodiments)
In addition, embodiment disclosed this time is an illustration in all the points, Comprising: It does not become a basis of limited interpretation. Therefore, the technical scope of the present invention is not construed only by the above-described embodiments, but is defined based on the description of the scope of claims. Further, the technical scope of the present invention includes all modifications within the meaning and scope equivalent to the scope of the claims.

  For example, in the embodiment, the example in which the vehicle 100 is the FF has been described. However, the present invention is not limited to this, and the vehicle may be an FR (front engine / rear drive) or may be a four-wheel drive. .

  The target torque phase time may be given as a hydraulic sweep control time for hydraulic control for the disengagement side frictional engagement element or hydraulic control for the engagement side frictional engagement element.

  Further, the execution time of the torque-down return control (execution time determined according to the torque return rate) is the hydraulic pressure in the hydraulic control for the release-side frictional engagement element or the hydraulic control for the engagement-side frictional engagement element. You may make it correct | amend based on responsiveness. For example, when the friction engagement element has a slow hydraulic pressure release characteristic or when the oil temperature is low, correction is performed so that the execution time of the torque-down return control is lengthened.

  In addition, the execution time of the torque-down return control may be corrected based on parameters related to the input torque and the torque-down amount. For example, when the torque down amount is small, correction is performed so as to shorten the execution time of the torque down return control (increase the torque return ratio).

  In addition, although an example in which the torque phase control execution time is determined based on the target torque phase time is disclosed this time, the torque phase control execution time may be determined by setting the hydraulic pressure command value gradient at the time of clutch switching. .

  The present invention is applicable to a vehicle control device that performs engine torque-down control during a power-on downshift of an automatic transmission.

1 Engine (drive power source)
3 Automatic transmission 5 ECU
C1-C4 clutch (friction engagement element)
B1, B2 Brake (Friction engagement element)

Claims (1)

A stepped automatic transmission that establishes one of a plurality of shift stages by selectively engaging a plurality of friction engagement elements, and outputs torque toward the input shaft of the automatic transmission. In a control device applied to a vehicle equipped with a driving force source,
At the time of torque down control of the driving force source started near the synchronous rotational speed of the power-on downshift of the automatic transmission, the torque phase control execution time of the power-on downshift is determined at the end of the torque down control. A vehicle control apparatus comprising a torque return control unit that reduces a torque-down amount at a corresponding return rate.

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