JP2005337457A - Line pressure controller of automatic transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To follow up an actual line pressure to a target line pressure with good responsiveness even in such a travelling that an input torque is abruptly changed while improving fuel consumption. <P>SOLUTION: The varied amount ΔT of the input torque T when an ECO mode is selected is calculated (S4), and the varied amount ΔT of torque is compared with a set value To determining the responsiveness of line pressure variation (S12). When ΔT is smaller than To, the ECO mode control in which line pressure control is performed by setting the minimum value of a line pressure Pp required for each gear shift as a target line pressure P1 is performed (S13). On the other hand, when ΔT is equal to or larger than To, the ECO mode control is stopped, and a normal mode control in which the line pressure control is performed by setting the maximum value of the line pressure Pp required to the target line pressure P1 is performed (S14). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a line pressure control device for an automatic transmission that sets a target line pressure based on an input torque.

  An automatic transmission mounted on a vehicle such as an automobile adjusts a hydraulic pressure discharged from a shift oil pump to generate a line pressure, and the line pressure generates a friction engagement element for each shift (a shift clutch and a brake). Etc.) are selectively operated to obtain a predetermined gear position (gear position).

  In general, the line pressure is set according to the running state for each selected gear position. For example, Patent Document 1 (Japanese Patent Laid-Open No. 5-33856) includes a line pressure control map for each gear position, and refers to the line pressure control map corresponding to the selected gear position based on the throttle opening and the vehicle speed. Thus, a technique for setting the line pressure is disclosed.

In the technique disclosed in Patent Document 1, the line pressure is set for each gear position based on the throttle opening and the vehicle speed. In contrast, the line pressure can be set to the minimum necessary value, the burden on the oil pump for shifting can be reduced, and fuel consumption can be improved.
JP-A-5-33856

  However, for example, when the throttle opening and the vehicle speed change rapidly or frequently, such as when driving on roads with continuous curves, driving in mountainous areas, or driving in urban areas, the line pressure Is set to the minimum necessary value for each gear position, so that the line pressure cannot follow the change of the driving condition with good responsiveness.

  As a result, it is not possible to obtain a driving according to the driver's intention, giving the driver an uncomfortable feeling such as insufficient acceleration or insufficient engine brake.

  In view of the above circumstances, the present invention makes the actual line pressure follow the target line pressure with good responsiveness even in a traveling state where the input torque changes rapidly or changes frequently while improving fuel efficiency. An object of the present invention is to provide a line pressure control device for an automatic transmission.

  In order to achieve the above object, according to the first aspect of the present invention, the input side is connected to the engine, the target line pressure is set based on the input torque from the engine, and the actual line pressure is controlled to follow the target line pressure. In the line pressure control device for an automatic transmission, an economy mode and a normal mode are freely selectable as the line pressure control mode, and when the economy mode is selected, the target line pressure is set to a shift stage during driving. Set based on the input torque, and when the normal mode is selected, set the maximum value of the line pressure required for each operating region where all the gears are set by the input torque as the target line pressure. Features.

  The second invention is characterized in that, in the first invention, even when the economy mode is selected, when the input torque changes abruptly or changes frequently, the mode is switched to the normal mode.

  According to a third aspect of the present invention, the input side is connected to the engine, the target line pressure is set based on the input torque from the engine, and the line pressure of the automatic transmission controls the actual line pressure to follow the target line pressure. In the control device, the driving condition is determined based on the parameter indicating the driving state, and when the driving condition is stable, the target line pressure is set based on the shift stage during driving and the input torque, When the driving conditions change rapidly or change frequently, the maximum value of the line pressure required for each operating state in which all gears are set based on the input torque is set as the target line pressure. It is characterized by doing.

  According to the present invention, the actual line pressure can be made to follow the target line pressure with good responsiveness even in a traveling state where the input torque changes suddenly or changes frequently while improving fuel efficiency. It is possible to travel according to the driver's intention.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram of a line pressure control device for an automatic transmission.

  Reference numeral 1 in the figure denotes an engine, and an automatic transmission 3 is connected to the engine 1 via a torque converter 2, and an output shaft (transmission output shaft) 3a of the automatic transmission 3 is a drive wheel (not shown). To be connected to.

  The engine 1 includes an engine speed sensor 4 that detects the engine speed from the rotation of the crankshaft and the like, and an intake pipe pressure sensor 5 that detects the intake pipe pressure downstream of the throttle valve as an absolute pressure. In an engine control unit (ECU) (not shown), based on the engine speed Ne detected by the engine speed sensor 4 and the intake pipe pressure Pin downstream of the throttle valve detected by the intake pipe pressure sensor 5, A fuel injection amount (time) for the injector disposed in each cylinder is set, and a fuel injection signal is output to the injector of the corresponding cylinder at a predetermined timing.

  Further, in the engine control device, based on the accelerator opening degree Acc detected by the accelerator opening sensor 6 that detects the depression amount of the accelerator pedal, the acceleration operation or the deceleration operation is detected from the change amount, and during the acceleration operation, the fuel injection amount is detected. When the fuel cut condition including the deceleration operation is satisfied, a fuel cut signal or the like is output to the injector to perform fuel cut control.

  The automatic transmission 3 receives the driving force of the engine 1 via the torque converter 2, and applies this driving force to the transmission output shaft 3a at a gear ratio corresponding to the gear stage (gear position) selected by the transmission mechanism 7. introduce. Then, driving wheels (not shown) are driven by the driving force from the transmission output shaft 3a, and the vehicle travels.

  The torque converter 2 has a gear shift oil pump 8 built therein. The speed change oil pump 8 is connected to the impeller shaft of the torque converter 2 and rotated integrally with the engine output shaft.

  On the other hand, the speed change mechanism 7 built in the automatic transmission 3 is configured by using, for example, a pair of planetary gear units, and in this embodiment, has a fourth forward speed. The speed of the speed change mechanism 7 is selected by engaging and disengaging the speed change frictional engagement element 9 including a speed change clutch and a brake provided corresponding to each speed change level.

  The operation of the speed change clutch constituting the speed change frictional engagement element 9 and the brake operation are performed by hydraulic pressure, and this hydraulic pressure is supplied from a hydraulic control valve 10 as hydraulic pressure control means. The hydraulic control valve 10 is provided with first and second shift solenoids 11 and 12 and a line pressure solenoid 13, and a speed change oil pump 8 is communicated with the input side.

  The first and second shift solenoids 11 and 12 can be operated in the combination shown in FIG. 2 to select a desired gear position. That is, the first speed is selected by turning on both shift solenoids 11 and 12. The second speed is selected by turning off the first shift solenoid 11 and turning on the second shift solenoid 12. Further, the third speed is selected by turning off both shift solenoids 11 and 12. Further, the fourth speed is selected by turning on the first shift solenoid 11 and turning off the second shift solenoid 12.

  The line pressure solenoid 13 adjusts the hydraulic pressure supplied from the speed change oil pump 8 by, for example, duty control, and generates the line pressure Pp [MPa] to be supplied to the selected speed change friction engagement element 9. It is. Each of the solenoids 11 to 13 is operated by a control signal from a transmission control unit (TCU) 21.

  On the input side of the TCU 21 are an engine speed sensor 4, an intake pipe pressure sensor 5, an accelerator opening sensor 6, a vehicle speed sensor 14 for detecting the vehicle speed from the speed of the transmission output shaft 3a, and an instrument panel or center (not shown). An ECO switch 15 for selecting an economy (ECO) mode disposed at a position where the driver can easily operate such as a console is connected.

  The ECO switch 15 is a switch that selects whether the target line pressure Pl is controlled according to the normal mode that emphasizes power driving or according to the ECO mode that emphasizes economic driving. The TCU 21 controls the target line pressure Pl according to the normal mode when the ECO switch 15 is OFF, and controls the target line pressure Pl according to the ECO mode when it is ON.

  FIG. 5 shows the target line pressure pattern. As shown in the figure, the target line pressure Pl [MPa] is controlled according to a preset target line pressure pattern based on the input torque T [N.m]. The target line pressure pattern is provided with gear-specific target line pressure patterns Lp1 to Lp4 and a maximum target line pressure pattern Lp0. The target line pressure patterns Lp <b> 1 to Lp <b> 4 for each shift speed correspond to the shift speeds (first speed to fourth speed) selected by the automatic transmission 3, respectively. The maximum target line pressure pattern Lp0 sets the target line pressure Pl when the normal mode is selected.

  The target line pressure patterns Lp1 to Lp4 for each gear are set to the minimum target line pressure Pl required for each gear (first to fourth) according to the input torque T. On the other hand, the maximum target line pressure pattern Lp0 sets the required maximum value of the line pressure Pp as the target line pressure Pl regardless of the gear position.

  As shown in FIG. 5, in the present embodiment, the third speed target line pressure pattern Lp3 indicates the maximum target line pressure, and therefore the maximum target line pressure pattern Lp0 is along the third speed target line pressure pattern Lp3. In addition, the value is set slightly higher than the target line pressure pattern Lp3 for the third speed.

  By the way, in the ECO mode control, the target line pressure patterns Lp1 to Lp4 for each gear are switched every time the gear set in the automatic transmission 3 is downshifted or upshifted. In general, when downshifting or upshifting the shift stage in the automatic transmission 3, first, a target line pressure pattern set corresponding to the shift stage on the downshift or upshift side is selected and the selected target is selected. The target line pressure Pl is set by referring to the line pressure pattern based on the input torque T. Then, after the actual line pressure Pp is increased to the target line pressure Pl, a shift clutch (and a brake) corresponding to the shift stage on the downshift or upshift side is engaged to change the speed.

  For example, when the gear stage is downshifted from the fourth speed to the third speed at the input torque T1 in FIG. 5, the target line pressure Pl is switched from Pla to Plb. However, since the actual line pressure Pp cannot be instantaneously increased to the target line pressure Plb, there is a certain delay in operation until the shift clutch (and the brake) is engaged and shifted.

  In normal driving, even if there is some delay in operation when operating a downshift or upshift, the driving conditions will not change suddenly, so it will not give the driver a sense of incongruity, but on roads with continuous curves. When traveling in a mountain, traveling in a mountain area, or traveling in an urban area, acceleration and deceleration are repeatedly operated. Therefore, the automatic transmission 3 performs control for switching between downshift and upshift each time. Is called.

  In the ECO mode control, even if an upshift and a downshift are to be performed, the speed is changed until the actual line pressure Pp follows the target line pressure Pl set corresponding to the downshift or the upshift side gear. Can not do. Therefore, the actual line pressure Pp cannot be made to follow the target line pressure Pl with good responsiveness, and it becomes difficult to travel according to the driver's intention. As a result, the driver feels uncomfortable, such as insufficient acceleration or insufficient engine brake.

  Therefore, in the TCU 21 according to the present embodiment, the normal mode control is executed even when the ECO mode is selected in the driving condition where the shift stage of the automatic transmission 3 is frequently switched or suddenly switched. By doing so, the line pressure Pp is made to follow the target line pressure Pl with good responsiveness so that the vehicle can travel according to the driver's intention.

  Specifically, the line pressure control executed in the TCU 21 is processed in accordance with a line pressure control routine shown in FIG.

  In this routine, first, in step S1, it is determined whether to execute the ECO mode control, execute the normal mode control, or switch to the normal mode depending on the driving condition even if the ECO mode control is selected. Read parameters. These parameters are an ECO switch signal from the ECO switch 15, an accelerator opening signal from the accelerator opening sensor 6, and an engine speed signal from the engine speed sensor 4.

  In step S2, it is checked whether the ECO mode is selected based on the ECO switch signal. When the ECO mode in which the ECO switch 15 is ON is selected, the process proceeds to step S3. On the other hand, when the normal mode in which the ECO switch 15 is OFF is selected, the routine jumps to step S14, the normal mode control is executed, and the routine is exited.

  If it progresses to step S3, driving conditions will be determined in step S3-S12. First, in step S3, a map is referred to based on the accelerator opening degree Acc calculated from the accelerator opening signal and the engine speed Ne calculated from the engine speed signal, or from the engine 1 to the automatic transmission 3 by calculation. An input torque (input torque) T is calculated. The input torque T is a torque from the output shaft of the engine 1 at the time of lockup, and is a torque from the torque converter output shaft when the torque converter 2 is operating. Therefore, when the input torque T is set based on the torque from the output shaft of the engine 1, it is preferable to set the torque converter 2 in consideration of the characteristics of the torque converter 2 when the torque converter 2 is operating.

  FIG. 4 illustrates a torque map for setting the input torque T. The input torque T is set to a larger value as both the engine speed Ne and the accelerator opening degree Acc increase, and is set to a larger value as the accelerator opening degree Acc increases even if the engine speed Ne is lower. Is done. The input torque T may be set based on the intake pipe pressure Pin detected by the intake pipe pressure sensor 5 and the engine speed Ne. Alternatively, in the engine 1 provided with the throttle opening sensor, the input torque T may be set based on the throttle opening and the engine speed Ne.

  Next, the process proceeds to step S4, where the torque change amount ΔT is calculated from the absolute value of the difference between the input torque T set this time and the input torque T (-1) set at the previous routine execution (ΔT ← | T (− 1) -T |).

  Then, it progresses to step S5. In Steps S5 to S11, it is checked based on the integrated value It of the torque change amount ΔT whether or not the current running state is a running condition in which the input torque T changes frequently, such as running in a mountainous area. First, in step S5, an integrated value (torque change integrated value) It of torque change amount ΔT is calculated (It ← It + ΔT).

  Next, the process proceeds to step S6, where the count value C of the integration number counter is incremented (C ← C + 1), and the process proceeds to step S7, which corresponds to the count value C of the integration number counter and a set value Co (for example, 60 [sec]). Value). If the set time of C ≦ Co has not been reached, the process jumps to step S12. When the set number of times C> Co is reached, the process proceeds to step S8, the count value C of the integration number counter is cleared (C ← 0), and the process proceeds to step S9.

  In step S9, the torque change amount integrated value It and the set integrated value Ito are compared. The set integrated value ITo is a reference value for determining whether or not a traveling condition in which the input torque T changes frequently, such as traveling in a mountainous area. When the torque change amount integrated value It is lower than the set integrated value Ito (It <Ito), the change of the input torque T during the set time (C) is small, and the line pressure Pp is input even if the ECO mode control is executed. It is determined that the change in the torque T can be followed with sufficient responsiveness, and the process proceeds to step S10.

  On the other hand, when the torque change amount integrated value It is higher than the set integrated value Ito (It ≧ Ito), the input torque T frequently changes during the set time (C). In the ECO mode control, the line pressure Pp is It is determined that it is difficult to follow the change in the input torque T with good responsiveness, and the process branches to step S11. Then, in both steps S10 and 11, after the torque change amount integrated value It is cleared (It ← 0), the process proceeds to steps S12 and S14, respectively.

  When the process proceeds from step S7 or step S10 to step S12, the torque change amount ΔT is compared with a preset set value To to check whether or not the traveling state is fluctuating rapidly. For example, when the accelerator pedal is depressed suddenly, the input torque T changes suddenly, but at the same time kickdown control is performed in the transmission control. Therefore, for example, when the vehicle is traveling at the 4th speed, the gear position is lowered to the 3rd speed, and the target line pressure pattern to be used is switched from the 4th speed target line pressure pattern Lp4 to the 3rd speed target line pressure pattern. .

  This set value To is set according to the target line pressure pattern after switching when the target line pressure pattern is switched by downshifting or upshifting of the shift stage with respect to the change of the input torque T per calculation cycle. This is a value for checking whether or not the actual line pressure Pp can follow the target line pressure Pl with good responsiveness.

  When the torque change amount ΔT is less than the set value To (ΔT <To), that is, when the actual line pressure Pp can sufficiently follow the change in the target line pressure Pl, the process proceeds to step S13, where ECO Executes mode control and exits the routine.

  On the other hand, when it is determined in step S12 that the torque change amount ΔT is equal to or greater than the set value To (ΔT ≧ To), that is, it is difficult to cause the actual line pressure Pp to follow the change in the target line pressure Pl with good responsiveness. If not, the process proceeds to step S14.

  Then, when the process proceeds from step S11 or step S12 to step S14, the ECO mode control is stopped, the normal control mode is executed, and the routine is exited.

  As described above, when the ECO mode control is executed, the target line pressure Pl is set based on the input torque T with reference to the target line pressure patterns Lp1 to Lp4 that are set for each shift stage. The Since the target line pressure patterns Lp1 to Lp4 for each gear stage are set along the minimum target line pressure Pl, the load applied to the oil pump 8 for shifting is reduced, and the fuel efficiency is improved.

  On the other hand, when the normal mode control is executed, the target line pressure Pl is set regardless of the selected shift speed according to the maximum target line pressure pattern Lp0. Even when the vehicle is traveling in a city or traveling in an urban area, the actual line pressure Pp follows the target line pressure Pl with good responsiveness, even under traveling conditions in which downshifts and upshifts are frequently repeated. Can be made.

  In addition, when the ECO switch 15 is in the ON state, branching from step S11 or step S12 to step S14 and executing the normal mode control, this routine is started again, and after step S3, If it is determined that the ECO mode control is possible as a result of determining the traveling conditions, the process proceeds to step S13, and the ECO mode control is executed.

  In this case, control hunting may be prevented by providing a hysteresis when switching from the normal mode control to the ECO mode control. Various methods are conceivable as the hysteresis control. However, when it is determined that the ECO mode control is possible a plurality of times in succession, the normal control mode may be switched to the ECO mode control.

  As described above, in the present embodiment, the driver turns on the ECO switch 15 and executes the ECO mode control in which the target line pressure Pl is set according to the target line pressure patterns Lp1 to Lp4 for each gear stage set for each gear stage. Even when the driving condition is that the downshift or the upshift is frequently performed, the target line pressure Pl is set as the target line pressure P1 as the maximum value of the required line pressure Pp. Since the control is performed in accordance with the maximum target line pressure pattern Lp0, it is possible to follow the line pressure Pp with good responsiveness, and it is possible to give the driver a sufficient acceleration feeling and engine braking feeling. It is possible to travel along.

Schematic configuration diagram of line pressure control device for automatic transmission Explanatory drawing showing the relationship between the shift stage and the operation of the shift solenoid Flow chart showing line pressure control routine Illustration of torque map to set input torque Explanation of target line pressure table

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Engine, 2 ... Torque converter, 3 ... Automatic transmission, 3a ... Transmission output shaft, 4 ... Engine speed sensor, 5 ... Intake pipe pressure sensor, 6 ... Accelerator opening sensor, 7 ... Transmission mechanism, 8 ... Shifting oil pump, 9... Friction engagement element for shifting, 10... Hydraulic control valve, 11... First shift solenoid, 12. Switch, Acc ... Accelerator opening, Ne ... Engine speed, Pin ... Intake pipe pressure, T ... Input torque

Agent Patent Attorney Susumu Ito

Claims (3)

In the line pressure control device for an automatic transmission that connects the input side to the engine, sets the target line pressure based on the input torque from the engine, and controls the actual line pressure to follow the target line pressure,
An economy mode and a normal mode are freely selectable as the line pressure control mode.
When the economy mode is selected, the target line pressure is set based on the shift stage during driving and the input torque,
When the normal mode is selected, the line pressure control of the automatic transmission is characterized in that the maximum value of the line pressure required for each operation region in which all the speeds are set by the input torque is set as the target line pressure. apparatus. 2. The line pressure of an automatic transmission according to claim 1, wherein even when the economy mode is selected, the line speed of the automatic transmission is switched to the normal mode when the input torque changes abruptly or changes frequently. 3. Control device. In the line pressure control device for an automatic transmission that connects the input side to the engine, sets the target line pressure based on the input torque from the engine, and controls the actual line pressure to follow the target line pressure,
The driving condition is determined based on the parameter indicating the driving state, and when the driving condition is stable, the target line pressure is set based on the shift stage during driving and the input torque, while the driving condition is When the speed changes rapidly or changes frequently, the maximum value of the line pressure required for each operating state in which all the shift speeds are set based on the input torque is set as the target line pressure. Line pressure control device for automatic transmission.

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