JP4305237B2 - Control device for automatic transmission - Google Patents

Description

  The present invention relates to a control device for an automatic transmission, and more particularly to a control device that improves control characteristics during a shift transition period.

  An automatic transmission mounted on a vehicle is configured to include a transmission mechanism that is connected to an engine via a torque converter or the like and has a plurality of power transmission paths. For example, an automatic transmission is automatically set based on an accelerator opening and a vehicle speed. The power transmission path is automatically switched, that is, the gear ratio (travel speed stage) is automatically switched. Generally, a vehicle having an automatic transmission is provided with a shift lever operated by a driver, and a shift position (for example, a reverse travel position, a neutral position, a forward travel position) is set based on the shift lever operation. The automatic shift control is performed within the thus set shift position (usually in the forward travel position).

  Normally, at the forward travel position selected during vehicle travel, shift control is executed based on a shift line (shift map) determined from the vehicle speed and the throttle opening (accelerator opening). Such shift lines are set differently for upshifts and downshifts. When the shift line is crossed, an upshift or a downshift is executed.

  In an automatic transmission that employs a transmission gear mechanism, a gear position is set by selectively hydraulically operating frictional engagement elements such as a clutch and a brake provided in the transmission gear mechanism. For example, when an upshift is executed from a certain gear position, control is performed to apply a hydraulic pressure to the clutch that has been in the non-engaged state until then to change to the engaged state.

  In such a speed change process, the transmission gear ratio of the speed change gear mechanism is changed, so that the rotational speed of the rotary member connected to the input shaft of the speed change gear mechanism is inevitably changed. As a result, the rotational energy corresponding to the change in the rotational speed is superimposed on the drive torque as an inertia torque and appears as a shift shock.

  In order to reduce such a shift shock, the inertia torque may be lowered. In order to lower the inertia torque, the time from the start of engagement of the friction engagement element to the end of engagement (inertia phase period) is lengthened so that the engagement of the friction engagement element proceeds slowly, What is necessary is just to dissipate the rotational energy of a rotating member as friction heat by the sliding of the friction engagement element in the meantime. In this case, the rotational energy of the rotating member increases in proportion to the square of the input shaft rotational speed difference before and after the shift.

  From such a viewpoint, it is conceivable to control the hydraulic pressure applied to the frictional engagement element so that the inertia phase period becomes longer as the vehicle speed increases, that is, as the input shaft rotational speed difference increases. However, in this case, the inertia torque can be sufficiently absorbed, but there is a problem that the inertia phase period becomes longer at a high vehicle speed range and the durability of the friction engagement element is impaired.

  In addition, it is conceivable to perform control so that the inertia phase period is constant in all shift changes so as not to impair the durability of the friction engagement elements. However, if this is done, the inertia torque increases in proportion to the square of the input shaft rotational speed difference, so that when shifting is performed where the input shaft rotational speed difference is small, the shift is smooth, but the input shaft rotational speed difference is small. There is a problem that a large shift shock occurs when shifting at a large position.

  For this reason, it can be considered that the rotational energy absorbed by the friction engagement element is controlled to be reduced by reducing the generated torque itself of the engine. The amount of torque reduction is determined according to the type of shift (1 → 2 shift, 2 → 3 shift, etc.) and the magnitude of engine torque (for example, throttle opening). This is because when the engine torque is lowered, the drive torque is lowered. Therefore, the base of the drive torque can be lowered by reducing the engine torque corresponding to the inertia torque, and the shift shock can be reduced.

  In addition, by appropriately combining these techniques, the inertia phase period is set in a range that does not impair the durability of the friction engagement element, and both reduction of the inertia torque and securing of the durability of the friction engagement element are achieved, Further, it is conceivable to reduce the shift shock by using the torque down control together.

  As described above, Japanese Patent Laid-Open No. 6-129273 (Patent Document 1) discloses a drive torque control device that absorbs a difference in drive torque due to a difference in speed ratio before and after a shift and reduces a shock during a shift.

  The drive torque control device disclosed in this publication includes a memory that stores a target drive torque characteristic such that the drive torque before and after shifting is substantially equivalent, and a control circuit that controls the output torque of the engine in accordance with this characteristic. The control circuit includes a circuit for reducing engine torque in order to suppress fluctuations in driving torque caused by inertia changes during gear shifting, a circuit for outputting engine torque higher than normal torque a predetermined time before the end of gear shifting, And a circuit for returning to the normal engine torque amount after a predetermined period after the end.

According to this drive torque control device, the engine torque for almost equalizing the drive torque before and after the shift is estimated from the gear ratio before and after the shift and the characteristics of the torque converter, and the intake air amount generated in the engine torque is given to the engine. . During the shift, the intake air amount is decreased by the shift command signal and the output-side turbine rotation of the torque converter, and the engine torque is reduced to suppress the drive torque fluctuation due to the inertia change. In addition, during a predetermined period before the end of the shift, the intake air amount is increased from the normal level to slow down the engine rotation speed and increase the engine torque. Prevents the engine from slowing down later. In this way, it is possible to suppress the torque converter output decrease immediately before and after the shift and realize a smooth shift.
JP-A-6-129273

  However, according to the drive torque control device disclosed in this publication, the output torque of the engine is controlled according to the target drive torque characteristics. For this reason, when the target drive torque fluctuates during the shift transition period, the engine output torque fluctuates. At this time, it is difficult to perform optimal hydraulic pressure control in accordance with changes in engine torque because the hydraulic response and the engine response are different. As a result, it has been difficult to achieve good shift characteristics during the shift transition period (especially the inertia phase period).

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a control device for an automatic transmission that has excellent shift characteristics during a shift transition period.

  A control device for an automatic transmission according to a first aspect of the present invention is a calculation means for calculating a target driving force for a vehicle, and a first target of a power source mounted on the vehicle based on the calculated target driving force. A first target torque setting means for setting the torque, a power source control means for controlling the power source so as to generate the set target torque, and a power for which the state of the automatic transmission is predetermined. In order to set the hydraulic control means for setting the working hydraulic pressure of the hydraulic device to be transmitted and the target torque in the shift transition period to the second target torque that is a predetermined torque not based on the calculated target driving force. Second target torque setting means.

  According to the first invention, for example, when the inertia phase in which the power transmission by the friction engagement element is started after the lapse of the torque phase which is a shift transition period, the second target torque setting means The target torque may be a predetermined torque that is not based on the calculated target driving force (for example, a torque that does not vary in magnitude) during a predetermined period (for example, within an inertia phase period that is a shift transition period) It may be changed). If the torque of the power source does not change during the inertia phase period, the input torque of the automatic transmission does not change, so there is no need to perform hydraulic control according to the power source, and the torque changes as a predetermined torque. Even if it exists, since the state of the change is recognized by the control device, it is possible to easily perform the hydraulic control in accordance with the power source. In other words, it is possible to set the hydraulic pressure of the hydraulic servo, which is a hydraulic device, on the assumption that the torque of the power source does not fluctuate and the fluctuation state can be recognized. It becomes easy to optimally control. Note that this control does not respond to the accelerator operation or the change in the target driving force during the shift transition period, but the shift transition period is a short time and a step occurs in the output shaft torque. Shocks and the like do not fall into extremely unfavorable characteristics. As a result, it is possible to provide a control device for an automatic transmission that has excellent shift characteristics during a shift transition period.

  In the control apparatus for an automatic transmission according to the second invention, in addition to the configuration of the first invention, the second target torque setting means sets the second target torque to a torque smaller than the first target torque. Means for setting.

  According to the second aspect of the invention, for example, the second target torque in the inertia phase period which is a shift transition period is set to a torque smaller than the first target torque. By reducing the torque itself generated from the power source, the rotational energy absorbed by the frictional engagement element in the inertia phase can be reduced, the period of the inertia phase can be shortened, and the transmission characteristics can be improved.

  In the control apparatus for an automatic transmission according to the third invention, in addition to the configuration of the first or second invention, the second target torque setting means is provided when the target driving force changes due to a change in the accelerator opening. Even if it exists, the means for setting the target torque in a shift transition period to the 2nd target torque which is a torque of a predetermined magnitude | size is included.

  According to the third invention, even if the driver steps on the accelerator in the shift transition period, the target torque in the inertia phase period that is the shift transition period is set to the second target torque. For this reason, regardless of the driver's accelerator operation, torque reduced to the second target torque having a predetermined magnitude is generated from the power source during the inertia phase period. For this reason, even if the driver's accelerator operation occurs, the target torque of the power source does not change, the control of the hydraulic pressure of the hydraulic equipment is facilitated, and good shift characteristics can be realized.

  According to a fourth aspect of the present invention, there is provided a control device for an automatic transmission, in addition to the configuration according to any one of the first to third aspects, means for calculating a virtual target driving force based on an accelerator operation amount during shifting. Virtual target torque calculation means for calculating the virtual target torque of the power source based on the virtual target driving force, and when the virtual target torque exceeds a predetermined range of torque, the target torque in the shift transition period is In place of the second target torque, a third target torque setting means for setting the third target torque according to the virtual target torque is further included.

  According to the fourth aspect of the invention, the virtual target torque calculated corresponding to the accelerator operation of the driver who is shifting is set as the target torque in the inertia phase period instead of the second target torque. This is done only when the virtual target torque exceeds a predetermined range of torque. In the case where the virtual target torque exceeds a predetermined range of torque due to the driver's large accelerator operation or the like, the driver's request can be met in response to the driver's accelerator operation.

  In the automatic transmission control apparatus according to the fifth aspect of the invention, in addition to the configuration of the fourth aspect of the invention, the third target torque setting means is configured so that when the virtual target torque exceeds the range on the upper limit side, Means for setting the torque calculated by adding the excess of the target torque to the second target torque as the third target torque is included.

  According to the fifth invention, the target torque within the inertia phase period is set using the torque calculated by adding the excess of the virtual target torque from the upper limit to the second target torque. Thereby, when the driver depresses the accelerator pedal during the shift transition period, the request can be met.

  In the automatic transmission control apparatus according to the sixth aspect of the invention, in addition to the configuration of the fourth aspect of the invention, the third target torque setting means sets the virtual target torque when the virtual target torque exceeds the range on the lower limit side. Means for setting as a third target torque is included.

  According to the sixth aspect, when the virtual target torque is small, the target torque within the inertia phase period is set using the virtual target torque. Thus, when the driver depresses the accelerator pedal during the shift transition period, the request can be met.

  In the automatic transmission control device according to the seventh aspect of the invention, in addition to the configuration of the fourth aspect of the invention, the speed change is a power-on upshift, and the second target torque is the power source torque before the start of the inertia phase. Is a value reduced by a predetermined amount. The control device for the automatic transmission sets the target torque in the inertia phase to the virtual target torque instead of the second target torque when the virtual target torque falls below the second target torque during the inertia phase. The fourth target torque setting means is further included.

  According to the seventh invention, in the power-on upshift, the second target torque can be set based on the power source torque before the start of the inertia phase. When the virtual target torque is lower than the second target torque by the accelerator operation, the target torque during the inertia phase can be set to the virtual target torque according to the driver's operation. Thereby, it can respond to a driver | operator's accelerator operation.

  In addition to the configuration of any one of the first to seventh aspects, the control device for the automatic transmission according to the eighth aspect of the invention controls learning of the hydraulic pressure of the hydraulic equipment when the second target torque is set. And further includes means for authorizing.

  According to the eighth aspect of the present invention, when the torque does not vary within a predetermined period (for example, within the inertia phase period), the input torque to the automatic transmission does not vary. Suitable for learning and controlling the hydraulic pressure of hydraulic equipment. Therefore, learning control can be permitted only in such a case to improve learning accuracy.

  In addition to the configuration of any one of the first to eighth inventions, the automatic transmission control device according to the ninth invention sets the target torque of the power source to the first target torque when the shift transition period ends. And a means for setting an operating oil pressure of the hydraulic device at the end of the shift transition period based on a difference between the actual torque and the first target torque in the shift transition period.

  According to the ninth invention, for example, based on the difference between the actual torque in the inertia phase that is the shift transition period and the first target torque, the working oil pressure of the hydraulic device at the end of the inertia phase can be set. The working hydraulic pressure at the end of the shift transition period can be accurately matched.

  In the automatic transmission control device according to the tenth invention, in addition to the configuration of any one of the first to ninth inventions, the shift is an upshift, and the hydraulic control means rotates the power source accompanying the shift. Before the number change, means for controlling the working oil pressure based on the first target torque, and means for controlling the working oil pressure based on the second target torque during the change of the rotational speed of the power source. Including.

  According to the tenth aspect of the invention, before the inertia phase starts (torque phase), the friction engagement element changes from the disengaged state to the engaged state based on the first target torque (which changes according to the target driving force). In the inertia phase where transmission is started, output torque from the power source (input torque to the automatic transmission) is controlled based on the second target torque (which does not change according to the target driving force). As a result, even in the inertia phase that is difficult to follow, the operating hydraulic pressure can be accurately matched.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

  Hereinafter, a power train of a vehicle including a shift control device according to an embodiment of the present invention will be described. The shift control apparatus according to the present embodiment is realized by an ECU (Electronic Control Unit) 1000 shown in FIG. In the present embodiment, the automatic transmission will be described as an automatic transmission having a planetary gear type transmission mechanism provided with a torque converter as a fluid coupling. In the following, a six-speed automatic transmission will be described, but the shift control device according to the present invention is not limited to such a six-speed automatic transmission.

  With reference to FIG. 1, the power train of the vehicle including the control device according to the present embodiment will be described. Specifically, the control device according to the present embodiment is realized by ECT (Electronic Controlled Automatic Transmission) _ECU 1020 shown in FIG.

  As shown in FIG. 1, the power train of this vehicle includes an engine 100, a torque converter 200, an automatic transmission 300, and an ECU 1000.

  The output shaft of engine 100 is connected to the input shaft of torque converter 200. Engine 100 and torque converter 200 are connected by a rotating shaft. Therefore, output shaft speed NE (engine speed NE) of engine 100 detected by engine speed sensor 400 and input shaft speed (pump speed) of torque converter 200 are the same.

  The torque converter 200 includes a lock-up clutch 210 that directly connects the input shaft and the output shaft, a pump impeller 220 on the input shaft side, a turbine impeller 230 on the output shaft side, and a one-way clutch 250. It is comprised from the stator 240 which expresses an amplification function. Torque converter 200 and automatic transmission 300 are connected by a rotating shaft. The output shaft rotational speed NT (turbine rotational speed NT) of the torque converter 200 is detected by a turbine rotational speed sensor 410. The output shaft rotational speed NOUT of the automatic transmission 300 is detected by the output shaft rotational speed sensor 420.

  FIG. 2 shows an operation table of the automatic transmission 300. According to the operation table shown in FIG. 2, the clutch elements (C1 to C4 in the figure), the brake elements (B1 to B4), and the one-way clutch elements (F0 to F3) that are friction elements are in any gear. Shows what is combined and released. For example, at the first speed (1st) used when the vehicle starts, the clutch element (C1) and the one-way clutch elements (F0, F3) are engaged. Engagement / release of these clutch elements and the like are controlled as shown in the operation table to realize a desired transmission gear stage.

  The ECU 1000 that controls these power trains includes an engine ECU 1010 that controls the engine 100 and an ECT (Electronic Controlled Automatic Transmission) _ECU 1020 that controls the automatic transmission 300.

  The ECT_ECU 1020 receives a signal representing the turbine rotational speed NT from the turbine rotational speed sensor 410 and a signal representing the output shaft rotational speed NOUT from the output shaft rotational speed sensor 420. Further, ECT_ECU 1020 receives from engine ECU 1010 a signal representing engine speed NE detected by engine speed sensor 400 and a signal representing throttle opening detected by the throttle position sensor.

  These rotation speed sensors are provided to face the teeth of the rotation detection gear attached to the input shaft of torque converter 200, the output shaft of torque converter 200, and the output shaft of automatic transmission 300. These rotational speed sensors are sensors that can detect slight rotations of the input shaft of the torque converter 200, the output shaft of the torque converter 200, and the output shaft of the automatic transmission 300. This is a sensor using a magnetoresistive element.

  In the forward travel (D) position, the ECT_ECU 1020 performs an optimal shift according to the vehicle speed (for example, calculated from the output shaft rotational speed NOUT) and the throttle opening from among “1st” to “6th” shown in FIG. The gear stage is determined, and a hydraulic pressure command signal for controlling the hydraulic circuit of the automatic transmission is output to the hydraulic equipment so as to realize the determined shift gear stage according to the operation table of FIG.

  The ECT_ECU 1020 calculates the target driving force by inputting the accelerator opening from the accelerator opening sensor 2000 or the target driving force from the cruise control computer. The ECT_ECU 1020 outputs an engine control signal to the engine ECU 1010 in order to control the output torque from the engine 100 in order to generate such driving force (output shaft torque).

  The engine 100 torque includes “target engine torque” determined from accelerator operation and target driving force, “engine torque according to throttle opening”, and engine torque after retarding the ignition timing in engine 100. There are three types of "actual engine torque". The virtual target torque is a torque determined by the driver's accelerator operation, and corresponds to the target engine torque. The virtual target torque includes one set on the computer side (that is, not based on the driver's accelerator operation) when the above-described cruise control computer is operating.

  A control structure of a program executed by ECT_ECU 1020 will be described with reference to FIG. FIG. 3 shows a control structure of a program executed at the time of upshifting.

  In step (hereinafter, step is abbreviated as S) 1000, the actual engine torque is set as the target engine torque. That is, the torque down control by the control (retarding control) for retarding the ignition timing of engine 100 is not performed. This shows a state before the inertia phase is started.

  In S1010, ECT_ECU 1020 determines whether or not an inertia phase has been started. This determination is made based on a change in the rotational speed of engine 100. When the inertia phase is started (YES in S1010), the process proceeds to S1020. If not (NO in S1010), the process returns to S1000.

  In S1020, the ECT_ECU calculates a torque reduction amount using the target engine torque, and executes torque reduction control by retarding control. At this time, the target engine torque is the engine torque according to the throttle opening.

  In S1030, ECT_ECU 1020 determines whether or not the difference between the actual engine torque and the target engine torque is large. If the difference between the actual engine torque and the target engine torque is large (YES in S1030), the process proceeds to S1040. If not (NO in S1030), the process proceeds to S1050.

  In S1040, ECT_ECU 1020 executes torque-down control so that the difference between the actual engine torque and the target engine torque is within the threshold value. Thereafter, the process proceeds to S1130.

  In S1050, ECT_ECU 1020 determines whether or not the torque-down limit by the retard angle control has been reached. When the torque-down limit by the retard control is reached (YES in S1050), the process proceeds to S1060. If not (NO in S1050), the process proceeds to S1070.

  In S1060, ECT_ECU 1020 executes torque-down control so that the actual engine torque is higher than the torque-down limit. Thereafter, the process proceeds to S1130.

  In S1070, ECT_ECU 1020 determines whether or not actual engine torque> target engine torque. If actual engine torque> target engine torque (YES in S1070), the process proceeds to S1080. If not (NO in S1070), the process proceeds to S1090.

  In S1080, ECT_ECU 1020 performs a torque down control end process. That is, the actual engine torque is equal to the target engine torque without using the retard angle. Thereafter, the process proceeds to S1130.

  In S1090, ECT_ECU 1020 determines whether or not it is in a driven state. This determination is made based on the relationship between the vehicle speed and the engine torque. If it is determined that the state is a driven state (YES in S1090), the process proceeds to S1100. If not (NO in S1090), the process proceeds to S1110.

  In S1100, ECT_ECU 1020 ends the torque-down control and switches to the driven control. Thereafter, the process ends.

  In S1110, ECT_ECU 1020 determines whether or not torque-down recovery has been started. When torque-down recovery is started (YES in S1110), the process proceeds to S1120. If not (NO in S1120), the process returns to S1020.

  In S1120, ECT_ECU 1020 executes torque down return control.

  A control structure of a program executed by ECT_ECU 1020 will be described with reference to FIG. FIG. 4 shows a control structure of a program executed at the time of downshift.

  In S2000, ECT_ECU 1020 sets the actual engine torque to the target engine torque. That is, there is no torque down control by the retard control. This state is a state until the inertia phase is started.

  In S2010, ECT_ECU 1020 determines whether or not an inertia phase has been started. When the inertia phase is started (YES in S2010), the process proceeds to S2020. If not (NO in S2010), the process returns to S2000.

  In S2020, ECT_ECU 1020 selects a shift mode from the amount of change in the target engine torque of the inertia phase. At this time, one shift mode is selected from a shift mode in which suppression of shift shock is important and a shift mode in which shift responsiveness that shortens the shift time is emphasized. The selection of the speed change mode is performed based on a change in the target engine torque until the start of the inertia phase.

  In S2030, ECT_ECU 1020 determines the engine torque according to the throttle opening based on the shift mode, regardless of the target engine torque. At this time, torque down control by retard angle control is not performed.

  In S2030, ECT_ECU 1020 determines whether or not the difference between the actual engine torque and the target engine torque is large. If the difference between the actual engine torque and the target engine torque is large (YES in S2040), the process proceeds to S2050. If not (NO in S2040), the process proceeds to S2060.

  In S2050, ECT_ECU 1020 adjusts the engine torque in accordance with the throttle opening so that the difference between the actual engine torque and the target engine torque falls within the threshold value. Thereafter, the process proceeds to S2120.

  In S2060, ECT_ECU 1020 determines whether or not a limit has been reached with respect to the synchronous torque-down target. If the limit is reached with respect to the torque reduction target at the time of synchronization (YES in S2060), the process proceeds to S2070. If not (NO in S2060), the process proceeds to S2080.

  In S2070, ECT_ECU 1020 adjusts the engine torque according to the throttle opening so as not to reach the synchronous torque-down limit. Thereafter, the process proceeds to S2120.

  In S2080, ECT_ECU 1020 determines whether or not it is in a driven state. If it is determined that the state is the driven state (YES in S2080), the process proceeds to S2090. If not (NO in S2080), the process proceeds to S2100.

  In S2090, ECT_ECU 1020 ends the torque-down control and switches to the driven control. Thereafter, this process ends.

  In S2100, ECT_ECU 1020 determines whether or not to start control at the time of synchronization. If it is determined that control at the time of synchronization is to be started (YES in S2100), the process proceeds to S2110. If not (NO in S2100), the process returns to S2030.

  In S2110, ECT_ECU 1020 executes torque-down control during synchronization. Thereafter, the process ends.

  In S2120, ECT_ECU 1020 determines that the precondition for the shift learning control is not satisfied. As described above, when it is determined that the precondition for the shift learning control is not satisfied, the learning control is not executed.

  An operation of a vehicle equipped with ECT_ECU 1020 that is the control device for the automatic transmission according to the present embodiment based on the above-described structure and flowchart will be described.

  FIG. 5 shows temporal changes of various state quantities at the time of upshift.

  The dotted line shown in FIG. 5 indicates the operation when the conventional control device is used, and the solid line indicates the operation when the control device according to the embodiment of the present invention is used. Conventionally, when the accelerator pedal is operated and the accelerator opening is opened during the shift transition (during the inertia phase period), the actual engine torque is increased accordingly, and the friction engagement element is engaged so as to follow it. Hydraulic control has been performed to increase the engagement pressure. At that time, the control responsiveness of the actual engine torque is good in following the change in the accelerator opening. On the other hand, the control responsiveness of the engagement pressure is not particularly good when the oil temperature is low, and the control is delayed due to wasted time.

  Therefore, in the ECT_ECU 1020 that is the control device for the automatic transmission according to the present embodiment, the actual engine torque is determined in a predetermined period (within the inertia phase period) even when the accelerator operation is performed in the inertia phase during the shift transition. ), Torque down control is executed so that a predetermined value which is a predetermined torque is obtained.

  Therefore, as shown in FIG. 5, the actual engine torque does not increase depending on the change in the accelerator opening as compared with the conventional change. In this way, the actual engine torque becomes a predetermined value that is a predetermined torque, the input torque to the automatic transmission 300 becomes constant, and the engagement pressure of the hydraulic device that operates the friction engagement element to be engaged is set. Can be easily adapted. In FIG. 5, the case of upshifting has been described. Similarly, during downshifting, the actual engine torque is controlled to be a predetermined value that is a predetermined torque during the inertia phase period. It is easy to adapt the engagement pressure for engaging the friction engagement element.

  With reference to FIG. 6, the time change of the various state quantities during the power-on upshift will be described.

  As shown by the actual engine torque in FIG. 6, the throttle opening is changed in accordance with the target engine torque. The actual engine torque is adjusted by the retard control of the engine 100. Therefore, the engine torque according to the throttle opening becomes the target engine torque.

  In FIG. 6, the actual engine torque is represented by a solid line, and the engine torque according to the throttle opening is represented by a dotted line. This is because in the case of retarded angle control, control is possible every time the air-fuel mixture is combusted, so the response is good.However, the control by the throttle opening is bad, so the target engine torque is the throttle opening. Accordingly, the actual engine torque is suppressed by retarding the ignition timing of the engine 100.

  Further, as shown in the engagement hydraulic control in FIG. 6, the hydraulic control before the bending point is calculated using the actual engine torque before the start of the inertia phase. In the hydraulic control after the inflection point, the actual engine torque after the torque reduction of the inertia phase is pre-read and the control is performed based on the value. The control at the end of the hydraulic pressure and the torque down return control are controlled based on the difference between the target engine torque and the actual engine torque before the return.

  Thus, even if the accelerator opening or the target engine torque (target driving force) is increased, the actual engine torque is determined by the ignition timing of the engine 100 while the throttle opening is changed in accordance with the target engine torque. Is reduced by retarding control. If the engine torque is increased during the shift, the hydraulic control cannot follow and the shift shock is worsened and the shift time is extended. However, this problem does not occur because the actual engine torque is reduced by the retard control. .

  FIG. 7 shows temporal changes of various state quantities during the power-on downshift.

  As shown in the accelerator opening degree or the target engine torque (target driving force) in FIG. 7, even if the target torque changes during the shift, the engine torque during the shift is not changed, and is followed by the return control. For this reason, as indicated by the actual engine torque, the actual engine torque is set to a certain form regardless of the target engine torque, and the shift level is stabilized. The engine torque is controlled according to the throttle opening.

  As shown in the actual engine torque, the engine torque according to the throttle opening decreases. However, the actual engine torque is assumed to be constant without following the target engine torque. It is controlled to follow. Since the actual engine torque is constant regardless of the target engine torque and the engine torque is stable, hydraulic controllability and adaptability are improved.

  In addition, since the shift shock at the time of synchronizing the rotation speed of the power-on downshift is determined by the change in the output shaft torque of the automatic transmission at the time of synchronization, when returning to the retard control, it is controlled by the return destination and the torque step before the return. The If the actual engine torque during the shift decreases in this way, the shift time becomes longer and the shift shock level deteriorates. However, as shown in FIG. 7, the actual engine torque can be varied as the target engine torque. Since the shape is constant, the actual engine torque during the shift does not decrease and the shift time does not become long.

  FIG. 8 shows temporal changes in the target engine torque when the accelerator is stepped on, the target engine torque when the accelerator is constant, and the target engine torque and actual engine torque when the accelerator is returned.

  As shown in FIG. 8, when the deviation between the target engine torque and the actual engine torque exceeds a threshold value or reaches the torque-down limit by the retard control, the deviation threshold value or the torque-down limit is reached. The actual engine torque is changed accordingly. This is a case where the driver's accelerator operation causes the difference between the target engine torque and the actual engine torque to exceed a threshold value, or a case where the torque down amount is large and the torque reduction limit by the retard control is reached. . In such a case, the actual engine torque is changed instead of a fixed shape. Thereby, an actual engine torque can be changed according to a driver | operator's request | requirement.

  Further, when the actual engine torque is greater than the target engine torque, or when driven determination is made, the torque down control is stopped. The actual engine torque is set as the target engine torque, and the hydraulic control is changed accordingly.

  That is, FIG. 8 shows that the deviation between the target engine torque and the actual engine torque is equal to or greater than a threshold value while the torque during the shift transition is in a certain form (within the target engine torque range). In the case where the actual engine torque has become larger than the target engine torque when the limit of torque reduction due to the retard control of the ignition timing of the engine 100 has been reached and when it is determined to be driven, The actual engine torque is changed without maintaining the actual engine torque in a certain form.

  Only when the target engine torque is within the range where the actual engine torque can be output as a certain form as a shift transient during the inertia phase, the engine torque during the shift transient can be made constant Only learning control may be performed. When it is outside the range, the learning control is not performed. However, the learning value is reflected.

  In this way, learning control is performed only when the actual engine torque is in a certain shape. Even if there is some variation in the target engine torque (even if the accelerator operation is not stable), the actual engine torque is stable, so that more precise learning control is possible. By not performing learning when the actual engine torque at the time of shifting transition is not stable, erroneous learning can be prevented.

  With reference to FIG. 9, torque down return control and hydraulic engagement end control at the end of the upshift will be described.

  FIG. 9 shows two cases (case (A) and case (B)) based on the difference between the target engine torque and the actual engine torque before return. Before upshift synchronization, the shock at the end of the shift can be reduced by increasing the engine torque or decreasing the engagement pressure. However, if the engine torque is too high with respect to the clutch engagement force, which is a friction engagement element, the clutch is released and the gear shift returns.

  Conventionally, the torque down return control and the hydraulic engagement end control are controlled using the actual engine torque before the return control, the engine torque according to the throttle opening, or the target engine torque.

  In the case of ECT_ECU 1020, which is a control device according to the present embodiment, the engine torque is stable during the shift transition period, but the engine torque at the return destination is different, so the feasibility of the control at the end of shift is important. By performing hydraulic control using the difference between the actual engine torque before return and the target engine torque, control can be performed regardless of the magnitude of the engine torque during the inertia phase, and controllability and adaptability are simplified. It is possible.

  As shown in FIG. 9, when the return control is started, in the case (A) where the difference between the target engine torque and the actual engine torque before the return is large, the target engine torque In the case (B) where the difference from the actual engine torque before returning is small, the engagement pressure is controlled to be low. That is, the hydraulic pressure of the engagement pressure is determined from the difference between the target engine torque and the actual engine torque before return. As a result, as shown by the turbine speed in FIG. 9, it is possible to reduce the shift shock that occurs at the end of the shift by soft landing.

  Referring to FIG. 10, a plurality of patterns of changes in actual engine torque during a shift transition period are prepared, and it is determined which pattern is selected according to changes in target engine torque until the start of inertia phase.

  In this way, by preparing a plurality of patterns for changes in engine torque during shift transition, stable hydraulic control is possible without being directly affected by changes in engine torque during shift transition over a wide range. That is, by limiting the engine torque and hydraulic pressure control to a plurality of (2 to 3) patterns, the balance between the shift time and the shift shock can be divided into responsiveness, shift shock reduction, etc. It becomes possible not to deteriorate the balance between the hysteresis and the shift shock by making the torque constant.

  As shown in FIG. 10, here, a case where three types of patterns (pattern (A), pattern (B), and pattern (C)) are set is shown. The change in the actual engine torque is larger in pattern (A) and smaller in pattern (C). Along with this, the change in the turbine rotation speed is larger in the pattern (A) and smaller in the pattern (C). The change in the engagement pressure is larger in the pattern (A) and smaller in the pattern (C). The pattern (B) is set between the pattern (A) and the pattern (C).

  The pattern (A) is employed when emphasizing responsiveness, and the pattern (C) is employed when emphasizing reduction of shift shock.

  Referring to FIG. 11, changes with time in the actual engine torque and the target engine torque when the driven determination is made are shown.

  As shown in FIG. 11, when the driven state is determined, an upshift determination is made and the engine torque is restored. When the target engine torque changes, the output torque is caused to follow within the range of the threshold value. However, when the torque-down control at the time of synchronization reaches a limit soon, the shape is not made constant. By making the shift transient torque in a certain form within the target engine torque range, the shift performance can be improved. On the other hand, if the upper limit of the target engine torque is exceeded, it will fall within that range In this way, when the actual engine torque is increased and the range of the target engine torque exceeds the lower limit, control is performed so that the actual engine torque becomes the target engine torque.

  FIG. 12A and FIG. 12B show the time change of the output shaft torque. The shift shock at the time of synchronization is determined by the step of the output shaft torque before and after synchronization. In order to reduce the shift shock during synchronization, torque down control is executed to control the vibration of the vehicle and suppress the shift shock. Since the step of the output shaft torque has a correlation with the difference between the engine torque before returning and the engine torque after returning, the torque reduction amount is calculated based on the difference.

  As shown in FIG. 12A, the pattern (D) and the pattern (E) are set according to the engine torque step at the time of synchronization. As shown in FIG. 12 (B), the output shaft torque after the change has better followability than the output shaft torque before the change. That is, by controlling the actual engine torque by setting the torque reduction amount so that the torque reduction amount increases as the torque step increases corresponding to the engine torque step during synchronization, and the torque reduction amount decreases as the step difference decreases. The vibration of the output shaft torque can be suppressed.

  As described above, according to the ECT_ECU that is the control device for the automatic transmission according to the present embodiment, the engine torque during the shift is set in a certain form regardless of the accelerator operation or the change in the target driving force. Thereby, since the input torque to the automatic transmission is always stabilized, the hydraulic control of the friction engagement element in the automatic transmission is stabilized, and the controllability and adaptability of the shift control are improved. Therefore, this can improve the transmission quality.

  More specifically, at the time of upshift, the target torque calculated from the target driving force is calculated until the start of the inertia phase. After the start of the inertia phase, the throttle opening changes following the target torque, but the actual engine torque is made to have a certain shape by retarding the ignition timing of the engine. After synchronization, the actual engine torque is returned to the target engine torque. On the other hand, during downshifting, the target engine torque calculated from the target driving force is output until the start of the inertia phase. After the start of the inertia phase, the actual engine torque is changed by the throttle so that the actual engine torque has a predetermined form regardless of the target torque. At this time, the retard control of the ignition timing of the engine is not used. Immediately before the synchronization, the throttle opening changes with the target engine torque as a target, but the actual engine torque is set to a certain form by the retard control. After synchronization, the actual engine torque is returned to the target engine torque. In this way, the frictional engagement of the automatic transmission is ensured because the engine torque during the shift is set to a certain shape regardless of the accelerator operation or the change in the target driving force in both cases of upshift and downshift. The hydraulic control of the element can be stabilized.

  In the shift control device described above, the actual engine torque is controlled so as to be a predetermined value that is a predetermined torque, and it is described so that it is easy to adapt the engagement pressure for engaging the friction engagement element. However, it may change instead of a fixed value. That is, the engine torque may be changed by a predetermined value.

  Further, in the above-described shift control device, the engine torque may be set to a predetermined output in the torque phase or the like in the transition phase, not limited to the inertia phase.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is a control block diagram of the automatic transmission according to the embodiment of the present invention. It is an operation | movement table | surface of the automatic transmission shown in FIG. It is a flowchart which shows the control structure of the program (upshift) performed by ECU which concerns on embodiment of this invention. It is a flowchart which shows the control structure of the program (downshift) performed by ECU which concerns on embodiment of this invention. It is a figure for demonstrating the speed change state at the time of an upshift. It is a figure for demonstrating the shift state at the time of a power-on upshift. It is a figure for demonstrating the shift state at the time of a power-on downshift. FIG. 6 is a diagram (No. 1) for describing a state of change in actual engine torque and target engine torque. It is a figure for demonstrating the state of the return control of a gear shift end. It is a figure for demonstrating the state which changed and distinguished the some shift pattern. FIG. 6 is a diagram (No. 2) for describing a state of change in actual engine torque and target engine torque. It is a figure for demonstrating the state of the change of an output shaft torque.

Explanation of symbols

  100 engine, 200 torque converter, 210 lock-up clutch, 220 pump impeller, 230 turbine impeller, 240 stator, 250 one-way clutch, 300 automatic transmission, 310 input clutch, 400 engine speed sensor, 410 turbine speed sensor, 420 Output shaft rotational speed sensor, 1000 ECU, 1010 Engine ECU, 1020 ECT_ECU, 2000 Accelerator opening sensor.

Claims (4)

A control device for an automatic transmission mounted on a vehicle, wherein the automatic transmission transmits an output torque of a power source mounted on the vehicle during a shift transition period of the automatic transmission to an output side,
Power source control means for controlling the power source so as to generate a target torque of the power source;
Calculating means for calculating a target driving force for the vehicle;
First target torque setting means for setting the target torque of the power source to the first target torque based on the calculated target driving force;
A hydraulic control means for setting an operating hydraulic pressure of a hydraulic device that brings the state of the automatic transmission into a predetermined power transmission state;
Second target torque setting means for setting a target torque of the power source in a shift transition period of the automatic transmission to a second target torque which is a predetermined torque not based on the calculated target driving force; ,
Means for calculating a virtual target driving force based on an accelerator operation amount during shifting;
Virtual target torque calculating means for calculating a virtual target torque of the power source based on the virtual target driving force;
When the virtual target torque exceeds a predetermined range of torque, the target torque of the power source in the shift transition period is replaced with the second target torque, and a third target corresponding to the virtual target torque is set. A control device for an automatic transmission, comprising: third target torque setting means for setting torque.   When the virtual target torque exceeds the range on the upper limit side, the third target torque setting means adds the excess of the virtual target torque from the upper limit to the second target torque and calculates the torque The control device for an automatic transmission according to claim 1, further comprising means for setting the torque as the third target torque.   The third target torque setting means includes means for setting the virtual target torque as the third target torque when the virtual target torque exceeds the range on the lower limit side. Control device for automatic transmission. The shift is a power-on upshift,
The second target torque is a value reduced by a predetermined amount with respect to the power source torque before the start of the inertia phase,
When the virtual target torque falls below the second target torque during the inertia phase, the control device for the automatic transmission replaces the target torque of the power source during the inertia phase with the second target torque, The control device for an automatic transmission according to claim 1, further comprising fourth target torque setting means for setting the virtual target torque.

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