JP5380381B2 - Automatic transmission and control method thereof - Google Patents

Description

  The present invention relates to control of an automatic transmission, and more particularly to start control at a low temperature.

  The automatic transmission realizes a plurality of shift stages by combining a plurality of planetary gear mechanisms and a plurality of friction engagement elements and changing the engagement state of the plurality of friction engagement elements. Generally, a start gear stage is realized by including a one-way clutch in a plurality of friction engagement elements, fastening a friction engagement element at the time of start, and locking the one-way clutch.

  However, when the hydraulic oil temperature of the transmission is low and the viscosity thereof is high, the one-way clutch components cannot shear the hydraulic oil and the one-way clutch cannot be locked. In this case, since the start gear stage cannot be realized, the vehicle cannot be started.

  Therefore, in the automatic transmission disclosed in Patent Document 1, when the hydraulic fluid temperature of the transmission is low, the transmission range is switched to the forward range (D range) from the non-traveling range (N range). Another frictional engagement element (B2 brake) that is different from the one frictional engagement element (C2 clutch) and the one-way clutch is engaged together with the certain frictional engagement element. This other frictional engagement element is a frictional engagement element that can achieve the starting gear stage by being engaged together with the certain frictional engagement element.

JP 2006-183705 A

  According to the method described in Patent Document 1, a start gear stage is realized by fastening the two friction engagement elements, and the vehicle can be started even if the one-way clutch cannot be locked.

  However, when trying to fasten the two frictional fastening elements in a situation where the viscosity of the hydraulic oil is high, a fastening delay occurs in any of the elements. Therefore, if the driver tries to start the vehicle immediately after the range is switched, there is a problem that the driving force input from the power source cannot be transmitted to the output shaft or cannot be transmitted sufficiently, and the start response becomes worse. It was.

  The present invention has been made in view of such technical problems, and an object of the present invention is to provide an automatic transmission and a control method therefor that can obtain a good start response even at low temperatures.

According to an aspect of the present invention, a first friction engagement element, a second friction engagement element, and a one-way clutch are provided, the first friction engagement element is released, the second friction engagement element is engaged, and The start gear stage is in any of the first engagement state in which the one-way clutch is locked and the second engagement state in which the first friction engagement element and the second friction engagement element are both engaged. An automatic transmission that is realized and shifts and outputs rotation input from a power source, and in a state where only the first frictional engagement element is engaged, the automatic transmission is in a state where it cannot transmit a driving force, In the temperature range of the hydraulic oil temperature where the one-way clutch lock failure occurs, after the timing when the starting operation is performed on the power source, the range of the automatic transmission is changed from the non-travel range to the forward range. The engagement of the first friction engagement element is started at a timing earlier than the timing at which the automatic transmission range is switched to, and the automatic transmission range is switched from the non-travel range to the forward range or at an earlier timing. An automatic transmission comprising a low temperature control means for performing low temperature control for starting the engagement of the second frictional engagement element is provided.

According to another aspect of the present invention, a first friction engagement element, a second friction engagement element, and a one-way clutch are provided, the first friction engagement element is released, the second friction engagement element is engaged, and The first shift state in which the one-way clutch is locked, and the second engagement state in which the first friction engagement element and the second friction engagement element are both engaged, the starting gear stage. Is realized, and a method of controlling an automatic transmission that shifts and outputs rotation input from a power source, wherein the automatic transmission cannot transmit a driving force when only the first frictional engagement element is engaged. ready, by the one-way clutch temperature range of hydraulic oil temperature which lock failure occurs in the power start operation is performed timing later relative source, and, whether the automatic transmission range is the non-driving range The engagement of the first friction engagement element is started at a timing earlier than the timing at which the forward range is switched, and the timing at which the range of the automatic transmission is switched from the non-travel range to the forward range or earlier. A control method for an automatic transmission is provided, which includes a procedure for performing low-temperature control for starting engagement of the second frictional engagement element.

  According to these aspects, since the timing of starting the fastening of the first frictional engagement element is earlier than in the conventional technique (Patent Document 1) in which the two frictional engagement elements are engaged at the timing when the transmission range is switched, The fastening delay of the first frictional engagement element can be eliminated or reduced, and a decrease in start response can be suppressed.

1 is an overall configuration diagram of a vehicle equipped with an automatic transmission according to a first embodiment of the present invention. It is a block diagram of the speed change mechanism of the automatic transmission. It is a fastening operation | movement table | surface of the automatic transmission. It is the figure which showed the control system of the automatic transmission. It is the flowchart which showed the start process of the low temperature control which a transmission controller performs. It is the flowchart which showed the completion | finish process of the low temperature control which a transmission controller performs. It is a time chart for demonstrating the effect of 1st Embodiment. It is the flowchart which showed the completion | finish process of the low temperature control which the transmission controller performs in 2nd Embodiment of this invention.

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

-First embodiment-
FIG. 1 shows the overall configuration of a vehicle equipped with an automatic transmission according to a first embodiment of the present invention. The transmission AT is an automatic transmission for an FF vehicle having four forward speeds and one reverse speed. As shown in FIG. 1, the transmission AT includes a converter housing 1, a torque converter 2, a transaxle case 3, a transmission input shaft 4, a transmission output gear 5, a transmission mechanism 6, and a reduction gear shaft. 7, a reduction gear mechanism 8, a differential gear mechanism 9, and drive shafts 10 and 11.

  Inside the converter housing 1, a torque converter 2 that realizes a start function and a vibration damping function is disposed. The torque converter 2 has a lockup clutch 12, and when the lockup clutch 12 is engaged, the crankshaft 13 of the engine Eng and the transmission input shaft 4 are directly connected.

  A transaxle case 3 is connected to the converter housing 1. Inside the transaxle case 3 are disposed a speed change mechanism 6 that realizes a speed change function, a forward / reverse switching function, and a neutral function, a speed reduction gear mechanism 8 that realizes a speed reduction function, and a differential gear mechanism 9 that realizes a differential function. Is done.

  The transmission mechanism 6 is disposed between the transmission input shaft 4 and the transmission output gear 5, and includes a front planetary gear FPG, a rear planetary gear RPG, a low clutch L / C, a low & reverse brake L & R / B, 2- It consists of a combination of 4 brakes 2-4 / B, reverse clutch REV / C, and high clutch H / C.

  The reduction gear mechanism 8 is configured by providing the reduction gear shaft 7 with a first reduction gear 14 that meshes with the transmission output gear 5 and a second reduction gear 16 that meshes with the drive input gear 15 of the differential gear mechanism 9. .

  The differential gear mechanism 9 equally distributes the driving force input from the drive input gear 15 while allowing the differential between the drive shafts 10 and 11 and transmits the same to the left front wheel and the right front wheel (not shown).

  FIG. 2 shows the configuration of the transmission mechanism 6 of the transmission AT.

  The transmission mechanism 6 is provided with a single pinion type front planetary gear FPG and a rear planetary gear RPG as planetary gears. As a friction engagement element, a low clutch L / C, a low & reverse brake L & R / B, a 2-4 brake 2-4 / B, a reverse clutch REV / C, and a high clutch H / C are provided. In addition, a one-way clutch OWC is provided in parallel with the low & reverse brake L & R / B.

  The front planetary gear FPG includes a front sun gear FS, a front ring gear FR, and a front carrier FC that supports a front pinion FP that meshes with both gears FS and FR.

  The rear planetary gear RPG has a rear sun gear RS, a rear ring gear RR, and a rear carrier RC that supports a rear pinion RP that meshes with both gears RS and RR.

  The front carrier FC and the rear ring gear RR are integrally connected by a first rotating member M1. The front ring gear FR and the rear carrier RC are integrally connected by the second rotating member M2. Therefore, by combining the front planetary gear FPG and the rear planetary gear RPG, four rotating elements (front sun gear FS, rear sun gear RS, first rotating member M1, second rotating member M2) obtained by subtracting two rotating elements from six rotating elements. ).

  The front sun gear FS is provided so as to be connectable / disengageable with the transmission input shaft 4 via the reverse clutch REV / C. It is provided so as to be fixed to the transaxle case 3 via a 2-4 brake 2-4 / B. The rear sun gear RS is provided so as to be connectable / disengageable with the transmission input shaft 4 via the low clutch L / C. The first rotating member M1 is provided so as to be fixed to the transaxle case 3 via a low & reverse brake L & R / B (one-way clutch OWC). And it is provided so that connection with the transmission input shaft 4 is possible via the high clutch H / C. The second rotating member M2 is directly connected to the transmission output gear 5.

  FIG. 3 is an engagement operation table of the transmission AT, and shows an engagement state of each friction engagement element for each shift stage. In the figure, ◯ indicates that the frictional engagement element is in an engaged state, and a blank indicates that the frictional engagement element is in a released state.

  The transmission AT realizes a forward fourth speed and a reverse first speed by changing the engagement state of each friction engagement element provided in the transmission mechanism 6.

  Specifically, when only the low clutch L / C is engaged, the one-way clutch OWC is locked (first engaged state), and the “first speed” in which the engine brake is not operated is realized. The “first speed” can be realized even when the low clutch L / C and the low & reverse brake L & R / B are engaged (second engaged state). In this case, the engine brake operates.

  Further, the “second gear” is realized by engaging the low clutch L / C and the 2-4 brake 2-4 / B. By engaging the low clutch L / C and the high clutch H / C, "3rd speed" is realized. By engaging the high clutch H / C and the 2-4 brake 2-4 / B, the “fourth speed” is realized. "Reverse gear" is realized by engaging reverse clutch REV / C and low & reverse brake L & R / B.

  Shifting from one shift stage to another shift stage is performed by performing a change-over shift in which one friction engagement element that has been engaged at a certain shift stage is released and one friction engagement element that has been released is engaged. Done.

  FIG. 4 shows a control system of the transmission AT. The control system of the transmission AT is roughly composed of a hydraulic control circuit and an electronic shift control system.

  The hydraulic control circuit includes an oil pump OP, a manual valve 20, a low clutch pressure regulating valve 21, a low clutch accumulator 22, a 2-4 brake pressure regulating valve 23, and a 2-4 brake accumulator 24. The dual pressure regulating valve 25, the switching valve 26, the solenoid 27, the high clutch inhibitor valve 28, the high clutch accumulator 29, and the low & reverse brake accumulator 30 are provided.

  In addition, the hydraulic control circuit communicates these components with a line pressure oil passage 31, a pilot pressure oil passage 32, a D range pressure oil passage 33, an R range pressure oil passage 34, and a low clutch pressure oil passage 35. A 2-4 brake pressure oil passage 36, a combined pressure output oil passage 37, a first high clutch pressure oil passage 38, a second high clutch pressure oil passage 39, a low & reverse brake pressure oil passage 40, Have

Oil pump OP is a hydraulic source for generating the line pressure P _L of the transmission AT. The oil pump OP is driven using a part of the driving force of the engine Eng.

  The operation of the select lever 41 is mechanically transmitted to the manual valve 20 via a shift cable, a link, a rod, etc., and the manual valve 20 is switched in conjunction with the operation of the select lever 41 by the driver. The select lever 41 is used to switch between the D range and the range of the transmission AT for realizing the gear range from the first gear (engine brake inactive) to the fourth gear, and the first gear (engine brake activated) and 2 Select one of the L range that realizes the speed, the R range that realizes the reverse gear, the neutral range N range that releases all clutches, and the P range that mechanically locks the transmission AT. It is a lever that can do.

  In this specification, “forward range” refers to the D range and does not include the L range. “Reverse range” refers to the R range, and “non-travel range” refers to the P range and the N range.

Manual valve 20, for example, at the time of D range selection, communicates the line pressure oil passage 31 and the D range pressure oil passage 33, guides the line pressure P _L to the D range pressure oil passage 33. When R range is selected, it communicates the line pressure oil passage 31 and the R position pressure oil passage 34, guides the line pressure P _L to R range pressure oil passage 34 as R range pressure P _R. When the D range or N range is selected, the manual valve 20 shuts off the line pressure oil passage 31 and the R range pressure oil passage 34 and drains the R range pressure oil passage 34.

The low clutch pressure regulating valve 21 is a three-way large-capacity linear solenoid valve of normal high (characteristic for generating hydraulic pressure when the power is turned off, the same applies hereinafter). Low clutch pressure adjusting valve 21, at the time of engagement of the low clutch L / C (1,2,3), a low clutch pressure by regulating the original pressure of the D range pressure P _D from the D-range pressure oil passage 33, It leads to the low clutch L / C through the low clutch pressure oil passage 35. Further, the low clutch pressure regulating valve 21 drains the low clutch pressure supplied to the low clutch L / C when the low clutch L / C is released (4, R).

The 2-4 brake pressure regulating valve 23 is a three-way large-capacity linear solenoid valve that is normally low (characteristic that does not generate hydraulic pressure when the power is turned off, the same applies hereinafter). 2-4 brake pressure adjusting valve 23, when the engagement of 2-4 brake 2-4 / B (2, 4), and by regulating the original pressure of the D range pressure P _D from the D-range pressure oil passage 33 2 The -4 brake pressure is guided to the 2-4 brake 2-4 / B through the 2-4 brake pressure oil passage 36. The pressure regulating valve 23 for 2-4 brake is a 2-4 brake supplied to the 2-4 brake 2-4 / B when the 2-4 brake 2-4 / B is released (1, 3, R). Drain pressure.

The dual-purpose pressure regulating valve 25 is a normal high 3-way large capacity linear solenoid valve. The combined pressure regulating valve 25 is a high clutch H that adjusts the hydraulic pressure that is regulated by using the hydraulic pressure (line pressure P _L ) supplied from the oil pump OP without passing through the manual valve 20 according to the switching state of the switching valve 26. Lead to / C or low & reverse brake L & R / B.

  The solenoid 27 is a normal low ON / OFF solenoid. When the solenoid 27 is OFF (no hydraulic pressure is generated), the switching valve 26 communicates with the combined pressure output oil passage 37 and the first high clutch pressure oil passage 38 to connect the low & reverse brake pressure oil passage 40 and the R range pressure. The oil passage 34 is communicated. Conversely, when the solenoid 27 is ON (hydraulic pressure is generated), the combined pressure output oil passage 37 and the low & reverse brake pressure oil passage 40 are communicated, and the low & reverse brake pressure oil passage 40 and the R range pressure oil passage 34 are communicated. And shut off.

  The switching valve 26 is switched by a transmission control unit (hereinafter referred to as “ATCU”) 50, which will be described later, controlling ON / OFF of the solenoid 27 in accordance with the transmission state of the transmission AT and the vehicle speed VSP.

The high clutch inhibitor valve 28 is disposed between the switching valve 26 and the high clutch H / C. High clutch inhibitor valve 28 is, the D range pressure P _D is switched in response to, the D range pressure P second high clutch pressure oil when the action of the _D channel 39 and the first high clutch pressure oil passage 38 which occurs upon selection of the D range communicating the door, draining second high clutch pressure oil passage 39 at the time of non-action of the D range pressure P _D.

  On the other hand, the electronic shift control system includes an ATCU 50 that includes a CPU, a memory, an input / output interface, an accelerator opening sensor 51 that detects an accelerator opening APO, a vehicle speed sensor 52 that detects a vehicle speed VSP, An input rotation speed sensor 53 for detecting the input rotation speed of the machine AT, an oil temperature sensor 54 for detecting the hydraulic oil temperature of the transmission AT, and an inhibitor switch for detecting the position (selection range) of the select lever 41 of the transmission AT. 55.

  The ATCU 50 receives signals from the sensors 51 to 55 and a signal from an ignition switch 56 that starts the engine Eng. The ignition switch 56 is a switch that can select any one of an OFF position, an ACC position, an ON position, and a START position, for example, by turning a key inserted into the key cylinder by the driver. While driving in the D range, the ATCU 50 sets the target gear stage ntGP by referring to the shift map based on the accelerator opening APO and the vehicle speed VSP, and the low clutch pressure regulating valve 21 so that the target gear stage ntGP is realized. A control command is output to the pressure regulating valve 23 for the 2-4 brake, the dual pressure regulating valve 25, and the solenoid 27. The shift map is a map in which an upshift line and a downshift line are written according to the accelerator opening APO and the vehicle speed VSP.

  In this embodiment, when the engine Eng is started and the vehicle starts, normally, the ATCU 50 engages only the low clutch L / C. As a result, the one-way clutch OWC is locked (first engaged state), the first speed, which is the starting gear, is realized, and the vehicle can be started.

  However, when the hydraulic oil temperature TMP of the transmission AT is lower than the lower limit temperature TMPLLIM at which the one-way clutch OWC starts to fail to lock, the components of the one-way clutch OWC can shear the hydraulic oil because the viscosity of the hydraulic oil is high. The one-way clutch OWC may not be locked. If the one-way clutch OWC cannot be locked, the first gear cannot be realized and the vehicle cannot be started.

  Therefore, the ATCU 50 performs control at low temperature in such a case so that the low & reverse brake L & R / B is engaged together with the low clutch L / C (second engagement state), and the one-way clutch OWC is not locked. Even so, the first gear is realized so that the vehicle can start (FIG. 5).

  However, at the first speed realized in this way, the engine brake always acts when the accelerator is off, and the drivability may be deteriorated. For this reason, it is not preferable that the low temperature control is engaged for a long time. Therefore, the ATCU 50 is low when the hydraulic oil temperature TMP rises and exceeds the lower limit temperature TMPLLIM, or when the shift to a gear position (for example, the second gear) that does not require locking of the one-way clutch OWC is performed. & Reverse brake L & R / B is released and control at low temperature is finished (Fig. 6).

  Hereinafter, the low temperature control performed by the ATCU 50 will be described with reference to FIGS. 5 and 6. The processes shown in FIGS. 5 and 6 are repeatedly executed by the ATCU 50. Hereinafter, the details of the low temperature control will be described with reference to these.

  FIG. 5 shows a low temperature control start process. This will be described below.

  First, in S <b> 11, the ATCU 50 determines whether the driver operates the ignition switch 56 and the signal from the ignition switch 56 has changed from OFF to ON. If a positive determination is made, the process proceeds to S12, and if a negative determination is made, the process ends. At the timing when the signal from the ignition switch 56 changes from OFF to ON, energization of the entire vehicle (an actuator such as a solenoid and an ignition coil) is started.

  Normally, the driver continuously operates the ignition switch 56 from the ON position to the START position, and in response to this, the engine Eng cranking and fuel injection are started. However, at this point, the engine Eng has not yet exploded, and the oil pump OP has not yet generated hydraulic pressure.

  In S12, the ATCU 50 determines whether the hydraulic oil temperature TMP detected by the oil temperature sensor 54 is equal to or lower than the lower limit temperature TMPLLIM at which the one-way clutch OWC lock failure starts to occur. The lower limit temperature TMPLLIM is not a temperature at which the one-way clutch OWC cannot be locked at all, but a temperature at which a locking failure starts to occur. The temperature TMPLLIM is determined according to the temperature characteristics of the hydraulic oil and the structure of the one-way clutch OWC, and is set based on the low-temperature viscosity index of the hydraulic oil, the guaranteed operation temperature of the one-way clutch OWC, experimental results, and the like. The lower limit temperature TMPLLIM is, for example, −10 ° C.

  If a positive determination is made in S12, the process proceeds to S13, and if a negative determination is made, the process proceeds to S14.

  In S13, the ATCU 50 issues a command (fastening command) to the dual pressure regulating valve 25 so that the hydraulic pressure necessary for the fastening is supplied to the low and reverse brake L & R / B. Specifically, the low and reverse brake L & R / B Increase the hydraulic target value for B and start engaging the low and reverse brake L & R / B. Further, the ATCU 50 sets ON indicating that the low temperature control is being executed in the low temperature control flag.

  Since the hydraulic oil temperature TMP is lower than the lower limit temperature TMPLLIM, the viscosity of the hydraulic oil is high. The fastening of B can be completed. In addition, there is no other friction engagement element that is engaged, no shock is generated by the engagement of the low & reverse brake L & R / B, and the transmission AT remains unable to transmit the driving force.

  At this time, in order to further prevent the delay in engaging the low & reverse brake L & R / B, set the hydraulic target value higher than when engaging the low & reverse brake L & R / B at the normal shift, and the low & reverse brake. You may make it increase the raise gradient of the supply hydraulic pressure to L & R / B.

  In S14, the ATCU 50 determines whether the select lever 41 is operated from the non-traveling range (P range or N range) to the forward range (D range) based on the signal from the inhibitor switch 55. If a positive determination is made, the process proceeds to S14, and if a negative determination is made, the process proceeds to S16.

  In S15, the ATCU 50 issues a command (engagement command) to the low clutch pressure regulating valve 21 so that the low clutch L / C is supplied with the hydraulic pressure necessary for its engagement. Increase the hydraulic target value and start engaging the low clutch L / C. Thereby, when the engagement of the low & reverse brake L & R / B is started at S13 (low temperature), the low clutch L / C and the low & reverse brake L & R / B are engaged (second engagement state), so Otherwise (normal time), only the low clutch L / C is engaged, and the one-way clutch OWC is locked in response to this (first engaged state). The first gear is realized in any fastening state.

  When the hydraulic oil temperature TMP is lower than the lower limit temperature TMPLLIM, the viscosity of the hydraulic oil is high, but since there is only one low clutch L / C to engage, the low clutch L / C should be engaged in a short time. Can be completed.

  In order to further prevent the delay in engaging the low clutch L / C at low temperatures, set the target hydraulic pressure higher than when engaging the low clutch L / C at normal speed and supply to the low clutch L / C. The increase gradient of the hydraulic pressure may be increased.

  Further, the ATCU 50 starts a timer for measuring an elapsed time after the select lever 41 is operated from the non-running range to the forward range.

  In S16, the ATCU 50 determines whether the select lever 41 has been operated from the non-traveling range (P range or N range) to the reverse range (R range) based on the signal from the inhibitor switch 55. If a positive determination is made, the process proceeds to S17, and if a negative determination is made, the process returns to S12.

  In S17, the ATCU 50 issues a command (release command) to the dual pressure regulating valve 25 so that the low & reverse brake L & R / B is released, drains the hydraulic pressure supplied to the low & reverse brake L & R / B, and low & Release the reverse brake L & R / B. Further, the ATCU 50 sets the low temperature control flag to OFF indicating that the low temperature control is not being executed.

  In S18, the ATCU 50 realizes the reverse shift speed. When the select lever 41 is operated to the R range, the manual valve 20 is switched so that the line pressure oil passage 31 and the R range pressure oil passage 34 communicate with each other, and the hydraulic pressure necessary for engaging the reverse clutch REV / C is changed. The reverse clutch REV / C is started to be engaged. The ATCU 50 issues a command (engagement command) to the dual pressure regulating valve 25 so that the low & reverse brake L & R / B is supplied with the hydraulic pressure necessary for the engagement after the reverse clutch REV / C is engaged, and the low & reverse brake Start L & R / B conclusion.

  Supplementing the processing of S17 and S18, although the low & reverse brake L & R / B is a frictional engagement element that needs to be engaged in order to realize the reverse speed, it is temporarily released in S17. This is to suppress the occurrence of shock and seizure of the reverse clutch REV / C. That is, in order to realize the reverse gear without generating a shock, it is necessary to engage the reverse clutch REV / C and the low & reverse brake L & R / B in this order, and the shock occurs when the order is reversed. . In this embodiment, in view of this point, the low & reverse brake L & R / B is temporarily released (S17), and the reverse clutch REV / C and the low & reverse brake L & R / B are engaged in this order (S18).

  FIG. 6 shows the low temperature control end processing. This will be described below.

  First, in S21, the ATCU 50 determines whether the low temperature control flag is ON. The low temperature control flag is a flag that is turned ON when the low & reverse brake L & R / B is engaged in S13 of FIG. If a positive determination is made, the process proceeds to S22, and if a negative determination is made, the process ends.

  In S22, the ATCU 50 determines whether the target shift speed ntGP set with reference to the shift map based on the accelerator opening APO and the vehicle speed VSP is the first speed. If an affirmative determination is made, the process proceeds to S23, and a negative determination is made, that is, a shift to a gear other than the first gear that does not require locking of the one-way clutch OWC is performed. The process proceeds to S25.

  In S23, the ATCU 50 determines whether the hydraulic oil temperature TMP exceeds the lower limit temperature TMPLLIM. If a positive determination is made, the process proceeds to S25, and if a negative determination is made, the process proceeds to S24.

  In S24, the ATCU 50 determines whether the elapsed time since the select lever 41 is operated from the non-traveling range to the forward range exceeds the predetermined time based on the value of the timer started in S15 of FIG. If a negative determination is made, the process proceeds to S25. If a negative determination is made, the process returns to S22. The predetermined time is set to a time when a sufficient time has elapsed from the operation of the select lever 41 and the hydraulic oil temperature TMP clearly exceeds the lower limit temperature TMPLLIM.

  In S25, the ATCU 50 issues a command (release command) to the dual pressure regulating valve 25 so that the low & reverse brake L & R / B is released, and drains the hydraulic pressure supplied to the low & reverse brake L & R / B. & Release the reverse brake L & R / B. Further, the low temperature control flag is set to OFF indicating that the low temperature control is not being executed.

Therefore, according to the above termination process, the following timing:
(a) Timing for shifting to the target gear stage ntGP that does not require locking of the one-way clutch OWC
(b) Timing when hydraulic fluid temperature TMP exceeds lower limit temperature TMPLLIM
(c) The low & reverse brake L & R / B is released at the earliest timing at which the elapsed time after operating from the non-traveling range to the forward range exceeds the predetermined time, and the low temperature control is terminated. .

  The release of the low & reverse brake L & R / B is achieved by engaging the low & reverse brake L & R / B, and at the first speed, the engine brake always acts when the accelerator is off, which may reduce drivability. The reason for releasing the low & reverse brake L & R / B at the above timing is as follows.

  The low temperature control is terminated at the timing of (a) because the one-way clutch OWC does not need to be locked at the target gear stage ntGP, and therefore the low & reverse brake L & R / B that is engaged instead of the one-way clutch OWC at low temperatures. This is because it is no longer necessary to conclude.

  The reason for terminating the low temperature control at the timing (b) is that the one-way clutch OWC can be locked. That is, even if the low & reverse brake L & R / B is released, the one-way clutch OWC is locked and the first gear is realized.

  The reason for terminating the low temperature control at the timing of (c) is that the hydraulic oil temperature clearly exceeds the lower limit temperature TMPLLIM even if the oil temperature sensor 54 fails to detect the hydraulic oil temperature. If so, it is for the low oil temperature control to be terminated.

  FIG. 7 shows how the vehicle starts when the engine Eng is started when the hydraulic oil temperature TMP is equal to or lower than the lower limit temperature TMPLLIM.

  At time t1, the ignition switch 56 is operated from the OFF position to the START position via the ON position, and thereafter, when the driver releases the ignition switch 56, the ignition switch 56 is automatically returned to the ON position. Energization of the entire vehicle (an actuator such as a solenoid and an ignition coil) is started when the ignition switch 56 is first turned ON. It starts when the position is reached. Since the above operation of the ignition switch 56 is performed in a short time, in FIG. 7, the signal from the ignition switch 56 is drawn from OFF to ON at a simplified time t1.

  When the signal from the ignition switch 56 is turned on at time t1, the hydraulic target value (solid line) of the low & reverse brake L & R / B is increased, and the engagement of the low & reverse brake L & R / B is started. The hydraulic oil viscosity is high and the actual hydraulic pressure of the low & reverse brake L & R / B (broken line) rises behind the target hydraulic pressure value (solid line), but only one low & reverse brake L & R / B is engaged. Therefore, the low & reverse brake L & R / B is concluded in a short time.

  After the time t1, the rotational speed Ne of the engine Eng continues to rise, and after the explosion completes and blows up once, it stabilizes at the idle rotational speed (time t2).

  When the driver operates the select lever 41 from the P range to the D range at time t3, the hydraulic target value (solid line) of the low clutch L / C is increased at this timing, and the engagement of the low clutch L / C is started. . The actual hydraulic pressure of the low clutch L / C (broken line) rises with a delay from the target hydraulic pressure (solid line) due to the high viscosity of the hydraulic oil, but only one low clutch L / C is engaged, and the oil pump OP Since sufficient hydraulic pressure is generated, the low clutch L / C is engaged in a shorter time than the low & reverse brake L & R / B.

  At time t4, the driver depresses the accelerator pedal, and the accelerator opening increases from 0 to 3/8. Since the first gear is realized by engaging the low & reverse brake L & R / B and the low clutch L / C, the vehicle can be started as soon as the accelerator pedal is depressed, and the vehicle speed VSP can be increased. . As a result, even when the one-way clutch OWC cannot be locked, it is possible to realize a good start response.

  The hydraulic oil temperature TMP starts to increase immediately after the engine Eng is started, and further increases when the vehicle speed VSP increases and the rotational speed of the rotary element in the transmission AT increases.

  When the hydraulic oil temperature TMP exceeds the lower limit temperature TMPLLIM at time t5, the low & reverse brake L & R / B is released, and the low temperature control ends.

  In this example, the low temperature control is completed at the timing when the hydraulic oil temperature TMP exceeds the lower limit temperature TMPLLIM, but the timing at which a shift is performed other than the first gear, the elapsed time since the selection lever 41 is operated. Even at the timing when the predetermined time has passed, the low temperature control ends.

  The effects of performing the low temperature control are as follows.

  In the above embodiment, when the hydraulic oil temperature TMP of the transmission AT is equal to or lower than the lower limit temperature TMPLLIM and the one-way clutch OWC cannot be engaged, the low & reverse brake L & R / B (when the ignition switch 56 is operated from OFF to ON) Low clutch L / C (second friction engagement) is started at the timing when the transmission AT range is switched from the non-traveling range (P range, N range) to the forward range (D range). The fastening of the element is started.

  Compared to the prior art (Patent Document 1), where the two friction engagement elements are engaged at the timing when the range of the transmission is switched, the timing for starting the engagement of the low & reverse brake L & R / B is earlier, so the low & reverse brake L & R / The fastening delay of B can be eliminated or reduced, and the start response can be improved (effects of the invention according to claims 1, 7, and 10).

  In addition, in order to engage the low & reverse brake L & R / B, it is necessary to adjust the pressure with the dual-purpose pressure regulating valve 25 and the switching valve 26. The load of the oil pump OP that supplies hydraulic oil to the road increases and fuel consumption deteriorates. However, in the above embodiment, since the low temperature control is performed only when the hydraulic oil temperature TMP of the transmission AT becomes equal to or lower than the lower limit temperature TMPLLIM, the deterioration of the fuel consumption can be minimized (claim 2). Effect of the invention).

  The rotation of the engine Eng rises and the oil pump OP begins to generate hydraulic pressure after the timing when the ignition switch 56 is operated from OFF to ON. However, if the engagement of the low & reverse brake L & R / B is started at the timing when the ignition switch 56 is operated, a solenoid valve or the like related to the engagement of the low & reverse brake L & R / B (in this embodiment, the dual pressure regulating valve 25) Since the oil pump OP generates the hydraulic pressure, the hydraulic pressure required for the low & reverse brake L & R / B is supplied after the oil pump OP generates the hydraulic pressure. The start response can be further improved by shortening the time required until the time is reached (effect of the invention according to claim 4).

  Moreover, in the said embodiment, the timing which fastens low & reverse brake L & R / B and the timing which fastens low clutch L / C are varied. Thereby, compared with the prior art (patent document 1) which fastens two friction fastening elements simultaneously, the load of oil pump OP can be reduced, the fastening delay of each friction fastening element can be made small, and start response is further improved. This can be improved (effect of the invention according to claim 3).

  The timing for starting the engagement of the low & reverse brake L & R / B is not limited to the timing when the ignition switch 56 is operated from OFF to ON, and is the timing after the timing when the ignition switch 56 is operated from OFF to ON, and If the transmission AT range is earlier than the timing at which the non-traveling range (P range, N range) is switched to the forward range (D range), at least the above-described effects can be expected.

  For example, the rotational speed Ne of the engine Eng is obtained from the engine controller, and the engagement of the low & reverse brake L & R / B is started at the timing when it is determined that the engine Eng has completely exploded based on the rotational speed Ne of the engine Eng. In addition, the same function and effect as those of the above-described embodiment are achieved (the function and effect of claim 6).

  Regarding the timing of engaging the low clutch L / C, if the range of the transmission AT is the P range, the transmission AT is mechanically locked, and the transmission AT is in a state where it can transmit the driving force. However, since the vehicle does not start, the timing (the timing when the range is switched from the non-running range (P range) to the forward range (D range)) can be made earlier. As a result, it is possible to suppress the engagement delay of the low clutch L / C and further improve the start response.

  However, if the range of the transmission AT is the N range, the transmission AT can transmit the driving force before the timing when the non-traveling range (N range) is switched to the forward range (D range). Is not preferable, and the timing for starting the engagement of the low clutch L / C needs to match the timing at which the range is switched.

  Further, in the above embodiment, the low & reverse brake L & R / at the timing when the hydraulic oil temperature TMP of the transmission AT exceeds the lower limit temperature TMPLLIM, or at the timing of shifting to the target gear stage ntGP that does not require locking of the one-way clutch OWC. B is released and control at low temperature is completed. In both cases, even when the low & reverse brake L & R / B is released, there are no problems such as inability to run and poor acceleration. The 1st speed realized by engaging the low & reverse brake L & R / B may cause the engine brake to always operate when the accelerator is off, reducing the drivability. At such timing, the low & reverse brake L & R / By releasing B, control at low temperature can be terminated without causing problems such as inability to run and acceleration failure, and the problem of reduced drivability due to continued low temperature control for a long time can be suppressed. It is possible (the operation and effect described in claim 8).

-Second Embodiment-
Subsequently, a second embodiment of the present invention will be described.

  The second embodiment is different from the first embodiment only in the low temperature control end process, and the process shown in FIG. 8 is executed instead of the process shown in FIG. 6 in order to end the low temperature control. The contents of the end process are the contents obtained by omitting the processes of S23 and S24 from the process shown in FIG.

Thereby, in the second embodiment, the following timing:
(a) The low & reverse brake L & R / B is released only at the timing of shifting to the target gear stage ntGP that does not require the one-way clutch OWC to be locked, and the low temperature control is terminated (S22 → S25).

Then, the following timing when the low temperature control is finished in the first embodiment:
(b) Timing when hydraulic fluid temperature TMP exceeds lower limit temperature TMPLLIM
(c) The low temperature control should not be terminated when the elapsed time from the non-travel range to the forward range has exceeded a predetermined time.

  When the low-and-reverse brake L & R / B is released and the one-way clutch OWC is locked, the function of regulating the rotation of the first rotating member M1 is passed from the low-and-reverse brake L & R / B to the one-way clutch OWC. Occur. However, in the second embodiment, the low & reverse brake L & R / B is released only at the timing of shifting to the target gear stage ntGP that does not require the one-way clutch OWC to be locked, so that a function for regulating such rotation is delivered. Therefore, the occurrence of shock can be prevented (the function and effect of claim 9).

  The embodiment of the present invention has been described above, but the above embodiment is merely an example of application of the present invention, and is not intended to limit the technical scope of the present invention to the specific configuration of the above embodiment. Various modifications can be made without departing from the spirit of the present invention.

  For example, low temperature control is started when the hydraulic oil temperature TMP of the transmission AT becomes lower than the lower limit temperature TMPLLIM at which the lock table of the one-way clutch OWC starts to be generated. However, the temperature condition for starting the low temperature control is not limited to this. For example, a predetermined temperature higher than the temperature at which the one-way clutch OWC starts to malfunction may be set, and the low temperature control may be performed below the predetermined temperature.

  Further, the present invention is not limited to the automatic transmission combined with the engine Eng as in the above embodiment, but also other power sources, for example, a power source composed of only a motor, an automatic combined with a power source combining the engine and the motor. The present invention can also be applied to a transmission.

If the power source is a motor, the engagement of the low & reverse brake L & R / B is started at the timing when the power switch of the motor is operated from OFF to ON instead of the timing when the ignition switch 56 is operated from OFF to ON. What should I do? Thereby, the same operation effect as the above-mentioned embodiment is produced (the operation effect of the invention according to claim 5).
In the above embodiment, the hydraulic oil temperature of the transmission AT is directly detected using the oil temperature sensor 54, but it may be estimated from the cooling water temperature, the outside air temperature, etc. of the engine Eng. In addition, since a certain degree of correlation is recognized between the coolant temperature of the engine Eng and the hydraulic oil temperature of the transmission AT, the above control is performed based on the coolant temperature of the engine Eng instead of the hydraulic oil temperature of the transmission AT. It may be.

  Moreover, although the said embodiment is equipped with the oil pump OP driven using a part of driving force of the engine Eng as a hydraulic power source, it replaces with this or provides an electric oil pump in addition to this. It is also possible. In the case of the oil pump OP that is driven by using a part of the driving force of the engine Eng, the hydraulic pressure cannot be generated until the rotational speed of the engine Eng increases, and the ignition switch 56 is operated from OFF to ON. Even if the engagement of the low & reverse brake L & R / B is started at the timing, there is a delay until the actual hydraulic pressure supplied to the low & reverse brake L & R / B rises. However, if an electric oil pump is used, hydraulic pressure can be generated at the timing when the ignition switch 56 is operated from OFF to ON, and such a delay can be eliminated.

  In the above embodiment, the starting speed is only the first speed, but the first friction engagement element (not limited to the low and reverse brake L & R / B) and the second friction engagement element (limited to the low clutch L / C). And a one-way clutch, the first frictional engagement element is released, the second frictional engagement element is engaged, and the one-way clutch is locked, and the first frictional engagement element and the second If it is an automatic transmission having a shift stage (not limited to the first speed stage, for example, the second speed stage) realized in the second engagement state in which the friction engagement element is engaged together, and any engagement state, The present invention can be applied when starting at the gear position.

Eng engine (power source)
AT automatic transmission 41 select lever 53 transmission control unit (ATCU)
54 Oil temperature sensor (Oil temperature acquisition means)
55 Inhibitor switch 56 Ignition switch
L & R / B Low & reverse brake (first friction engagement element)
OWC one-way clutch
L / C low clutch (second frictional engagement element)

Claims (10)

A first engagement that includes a first friction engagement element, a second friction engagement element, and a one-way clutch, wherein the first friction engagement element is released, the second friction engagement element is engaged, and the one-way clutch is locked State, the second engagement state in which the first friction engagement element and the second friction engagement element are both engaged, and the start gear stage is realized in any engagement state and is input from the power source An automatic transmission that changes the speed of rotation and outputs it,
In a state where only the first frictional engagement element is engaged, the automatic transmission is in a state where it cannot transmit a driving force,
The automatic transmission range is switched from the non-running range to the forward range after the timing when the starting operation is performed on the power source in the temperature range of the hydraulic oil temperature at which the one-way clutch lock failure occurs. The engagement of the first friction engagement element is started at a timing earlier than the first timing, and the second friction is performed at a timing when the range of the automatic transmission is switched from the non-running range to the forward range or earlier. An automatic transmission comprising low temperature control means for performing low temperature control for starting fastening of a fastening element. The automatic transmission according to claim 1,
The low temperature control means performs the low temperature control when the hydraulic oil temperature is equal to or lower than a temperature at which the one-way clutch lock failure starts.
An automatic transmission characterized by that. The automatic transmission according to claim 1 or 2,
The low temperature control means fastens the first friction engagement element and the second friction engagement element at different timings,
An automatic transmission characterized by that. The automatic transmission according to any one of claims 1 to 3,
The power source is a power source including an engine,
The low temperature control means starts fastening of the first frictional engagement element at a timing when the ignition switch of the engine is operated from OFF to ON.
An automatic transmission characterized by that. The automatic transmission according to any one of claims 1 to 3,
The power source is a power source including a motor,
The low temperature control means starts fastening the first frictional engagement element at a timing when the power switch of the motor is operated from OFF to ON.
An automatic transmission characterized by that. The automatic transmission according to any one of claims 1 to 3,
The power source is a power source including an engine,
The low temperature control means starts fastening of the first frictional engagement element at the timing when the engine is completely exploded.
An automatic transmission characterized by that. The automatic transmission according to any one of claims 1 to 6,
The low temperature control means starts the engagement of the second friction engagement element at a timing when the range of the automatic transmission is switched from the non-traveling range to the forward range.
An automatic transmission characterized by that. The automatic transmission according to any one of claims 1 to 7,
The low temperature control means may be a timing at which the hydraulic oil temperature exceeds the lower limit temperature after the first friction engagement element is engaged, or another shift that does not require the one-way clutch to be locked from the starting gear. Releasing the first frictional engagement element at the timing of shifting to a stage;
An automatic transmission characterized by that. The automatic transmission according to any one of claims 1 to 7,
After the first frictional engagement element is engaged, the low temperature control means continues the engagement of the first frictional engagement element even when the hydraulic oil temperature exceeds the lower limit temperature, and the one-way from the start gear stage. Releasing the first frictional engagement element at the timing of shifting to another gear stage that does not require clutch locking;
An automatic transmission characterized by that. A first engagement that includes a first friction engagement element, a second friction engagement element, and a one-way clutch, wherein the first friction engagement element is released, the second friction engagement element is engaged, and the one-way clutch is locked State, the second engagement state in which the first friction engagement element and the second friction engagement element are both engaged, and the start gear stage is realized in any engagement state and is input from the power source A method of controlling an automatic transmission that outputs rotation after shifting,
In a state where only the first frictional engagement element is engaged, the automatic transmission is in a state where it cannot transmit a driving force,
The automatic transmission range is switched from the non-running range to the forward range after the timing when the starting operation is performed on the power source in the temperature range of the hydraulic oil temperature at which the one-way clutch lock failure occurs. The engagement of the first friction engagement element is started at a timing earlier than the first timing, and the second friction is performed at a timing when the range of the automatic transmission is switched from the non-running range to the forward range or earlier. A control method for an automatic transmission, comprising a procedure for performing low-temperature control for starting fastening of a fastening element.

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