JP2007309500A - Abnormality diagnosing device of automatic transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform abnormality diagnosis in a predetermined timing in shifting in an automatic transmission in which liquid pressure applied to each frictional element is controlled by a hydraulic control device and shifting is attained by engagement or disengagement of each frictional element. <P>SOLUTION: Liquid pressure is supplied to liquid pressure passages 19, 20 of the frictional elements 10, 11 from the passages 21, 22 through individual pressure regulating valves 14, 15. A pressure source 25 for supplying liquid pressure is connected to the passages 21, 22, so that the passages are switched by the pressure regulating valves 14, 15 to supply liquid pressure to the liquid pressure passages 19, 20, thereby engaging the frictional elements 10, 11. When a command signal for engaging and disengaging the frictional elements 10, 11 reaches a determination timing, the on/off determination on the pressure switches 12, 13 connected to the liquid pressure passages 19, 20 is made to perform abnormal diagnosis on the automatic transmission. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an abnormality diagnosis device for an automatic transmission that controls a hydraulic pressure applied to each friction element and changes gear speed by engaging or releasing each friction element.

  Generally, the automatic transmission is shifted by controlling the hydraulic pressure applied to each friction element with a hydraulic pressure control device and engaging or releasing each friction element.

  In recent years, in order to simplify the hydraulic pressure path in automatic transmission control, a direct-acting valve type automatic transmission that directly controls the hydraulic fluid pressure of a friction element with individual direct-acting valves has been proposed. In this case, since there is no shift valve for selectively determining the hydraulic pressure path and switching the friction elements, an abnormality diagnosis as described in Patent Document 1, for example, is required.

  More specifically, Japanese Patent Application Laid-Open No. 2004-151899 describes that a gear change of a friction element is performed based on a command signal for releasing one friction element and a command signal for engaging another friction element. This is done by reducing or increasing the hydraulic pressure.

  Here, whether or not the friction elements are engaged is determined based on the on / off state of the pressure switches connected to the hydraulic pressure paths of the respective friction elements. This pressure switch changes its state from off to on when the hydraulic pressure applied to the pressure switch reaches a predetermined pressure (hereinafter referred to as “switching set pressure”). Determine if the element is engaged.

  At the time of shifting to change the friction element, the output signal of the pressure switch connected to the hydraulic pressure path of one friction element is switched from OFF to ON, so that it is determined that the friction element is moving toward engagement. When the output signal of the pressure switch connected to the hydraulic path of the other friction element is switched from on to off, it is determined that the friction element is moving toward release.

When the hydraulic pressure applied to the hydraulic pressure path of each friction element simultaneously reaches the switching set pressure during such shifting, it is determined that the interlock state is established. The interlock state is a state in which two or more friction elements to be switched at the time of shifting are simultaneously engaged. In this interlock state, the frictional element is dragged, resulting in heat loss and wear, which can cause a decrease in the durability of the frictional element. For this reason, at the time of shifting, the hydraulic pressure applied to the hydraulic pressure path of each friction element is detected by the pressure switch, and the interlock state is determined by the combination of the output signals of the pressure switch.
JP 2000-65203 A

  However, as shown in FIG. 11, the pressure switch has a characteristic of switching on and off within a certain range. For this reason, as shown in FIG. 11, when the pressure switch switching set pressure is a broken line portion, when the abnormality of the automatic transmission is diagnosed by the combination of the pressure switch on / off signal, the pressure switch is simultaneously turned on at time t1. Therefore, there is a possibility that erroneous determination is made that the friction elements 10 and 11 are in the interlocked state in which the friction elements 10 and 11 are simultaneously engaged even though the friction elements are normally switched. In addition, when one friction element is engaged or released, detection of an abnormality in the automatic transmission may be delayed if it is determined whether the friction element is engaged or released based only on the ON / OFF signal of the pressure switch. As described above, there is a case where the abnormality diagnosis of the automatic transmission at the time of shifting cannot be properly performed only by the ON / OFF signal of the pressure switch.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an automatic transmission abnormality diagnosis device that can appropriately detect abnormality of an automatic transmission at the time of a shift in which a friction element is engaged or released.

  In view of this, the invention according to claim 1 relates to the friction element and a state signal output means for outputting a state signal indicating whether the friction element is engaged or released based on the hydraulic pressure applied to the friction element of the automatic transmission. Friction element control for engaging and releasing a plurality of friction elements by individually controlling the hydraulic pressures of the plurality of friction elements by command signal output means for outputting command signals for coupling and releasing, and the command signal output means Command signal judging means for judging whether the friction element is engaged or released based on the status signal output by the status signal output means and the command signal of the command signal output means. And an abnormality diagnosis means for determining an abnormal state of the automatic transmission based on the command signal determination means.

  Thus, it is determined whether the friction element is engaged or released based on the command signal for engaging and releasing the friction element and the state signal output by the state signal output means. Machine abnormality diagnosis can be executed. In other words, the conventional automatic switch abnormality diagnosis is based only on the ON / OFF signal of the pressure switch. Therefore, especially when the pressure switch setting pressure is low, the ON / OFF of the pressure switch is switched within a certain range. In some cases, the automatic transmission is erroneously determined to be abnormal although it is normal due to the characteristics. In contrast, in the present invention, whether or not the friction element is engaged or released is determined based on a command signal for engaging and releasing the friction element, thereby diagnosing abnormality of the automatic transmission at an appropriate timing. In particular, even when the switching set pressure is low, the abnormality diagnosis of the automatic transmission can be appropriately executed.

  In addition, as in the invention according to claim 2, when the command signal output by the command signal output means reaches a preset command value, the state signal output by the state signal output means is used for friction. It may be determined whether the element is engaged or released. As described above, when the command signal for engaging and releasing the friction element reaches a preset command value, it is determined whether the friction element is engaged and released. A determination of element engagement or release can be made.

  As in the invention according to claim 3, the command value may be set based on the command signal when the status signal output by the status signal output means is switched from one state to the other state. . As a result, when the automatic transmission is normal, when the command signal to be engaged or released reaches the command value, it is determined that the friction element has switched from one state to the other, but there is an abnormality in the automatic transmission. If this occurs, it is determined that the friction element has not switched from one state even though the command signal to be engaged or released has reached the command value. can do.

  Further, as in the invention according to claim 4, the command for correcting the command value based on the past command signal when the state signal output by the state signal output means is switched from one state to the other state. You may make it provide a value correction means. Thus, by correcting the command value based on the past command signal, even when the command signal when the friction element switches from one state to the other state changes due to deterioration over time or the like, the automatic transmission Can be properly diagnosed.

  Further, as in the invention according to claim 5, the command value correcting means is configured such that when the command signal for correcting the correction signal is a command signal when it is determined that the abnormality diagnosis means is abnormal, the command signal It is better not to correct the command value by. As described above, if the command value is corrected with the command signal when it is determined to be abnormal, there is a possibility that the timing for determining whether or not the friction element is engaged or released is shifted. For this reason, when the automatic transmission is abnormal, the correction of the command value is prohibited.

  Further, as in the invention according to claim 6, the abnormality diagnosing means is the state signal regardless of whether the command signal output by the command signal output means has reached a preset command value by the command signal determining means. When it is determined that the state signal output by the output means is not switched, it is determined that the automatic transmission is abnormal. That is, if the friction element is not switched at the timing when the state is switched from one state to the other in the normal state, it is considered that an abnormality has occurred in the automatic transmission. .

  Further, as in the invention according to claim 7, the command signal output means is used to release one friction element by the friction element control means and to release the friction element at the time of shifting to engage the other friction element. The status signal is output at the later timing of the timing at which the output command signal reaches the command value and the timing at which the command signal output by the command signal to engage the friction element reaches the command value. The abnormal state of the automatic transmission may be determined based on the state signal output by the means.

  In other words, the friction at each timing is the earlier of the timing at which the command signal for releasing the friction element reaches the command value and the timing at which the command signal for engaging the friction element reaches the command value. If it is determined whether the element is engaged or released, it may be erroneously determined that the automatic transmission is abnormal. Therefore, determine whether each friction element is engaged or released at a later timing. Therefore, it is possible to prevent erroneous determination of abnormality in the automatic transmission.

  Further, as in the invention according to claim 8, based on the state signal output by the state signal output means of the friction element to be released and the state signal output by the state signal output means of the friction element to be engaged If it is determined that the friction element to be released and the friction element to be engaged are simultaneously released, it is preferable to determine that the automatic transmission is abnormal. Thereby, it is possible to determine an abnormal state of the automatic transmission in which the friction elements are simultaneously released.

Further, as in the invention according to claim 9, based on the state signal output by the state signal output means of the friction element to be released and the state signal output by the state signal output means of the friction element to be engaged If it is determined that the friction element to be released and the friction element to be engaged are simultaneously engaged, it may be determined that the automatic transmission is abnormal. Thereby, it is possible to determine an abnormality (interlock state) of the automatic transmission in which the friction elements are simultaneously engaged. Further, based on the command signal, the hydraulic pressure of each friction element is individually controlled, In order to engage or disengage the friction element, the command signal output by the command signal output means is a hydraulic pressure command value for controlling the hydraulic pressure of the friction element.

[Embodiment 1]
Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  1 and 2 are configuration diagrams that employ an abnormality diagnosis device for an automatic transmission. The automatic transmission incorporates a plurality of friction elements, and when each friction element is engaged, a predetermined gear is selected. The structure of the friction element built in the automatic transmission will be described. The automatic transmission includes a transmission main body, a torque converter (not shown), and a hydraulic controller. The transmission main body incorporates a plurality of planetary gears (not shown) and a hydraulic friction engagement element (hereinafter referred to as “friction element”) such as a hydraulic brake. FIG. 1 is a cross-sectional view showing a certain friction element 1 built in the transmission main body. As shown in FIG. 1, the friction element 1 is alternately stacked in addition to a disk-shaped clutch piston 5 in a bottomed double cylindrical clutch drum 4 having an inner cylinder 2 and an outer cylinder 3. The annular drive plate 6 and the driven plate 7 are each configured to be slidable in the axial direction.

  A port 8 is formed in the inner cylinder of the clutch drum 4. When high-pressure hydraulic oil is supplied from the port 8 into the clutch drum 4, the clutch piston 5 and the driven plate 7 are pressure-bonded to generate power. Transmission takes place. A plurality of clutch springs 9 are interposed between the inner cylinder 2 of the clutch drum 4 and the inner surface of the clutch piston 5, and when the hydraulic oil pressure decreases, the clutch springs 28 are urged to reduce the clutch pressure. The piston 5 moves backward to the left in the drawing.

  Next, the hydraulic controller will be described. The hydraulic controller is formed by an integrally formed hydraulic circuit or the like. In FIG. 2, hydraulic pressure is supplied to the hydraulic pressure paths 19 and 20 of the friction elements 10 and 11 from the paths 21 and 22 via the individual pressure regulating valves 14 and 15. The paths 21 and 22 are connected to a pressure source 25 that supplies hydraulic pressure, and the paths are switched by the pressure regulating valves 14 and 15, leading to the paths 21 and 22, and the hydraulic pressure is supplied to the hydraulic pressure paths 19 and 20. Is done. Thereby, the friction elements 10 and 11 are engaged. In addition, the hydraulic pressure paths 19 and 20 are reduced by switching the hydraulic pressure paths with the regulating valves 14 and 15 to communicate with the drain paths 23 and 24. Thereby, the friction elements 10 and 11 are released. Switching of the hydraulic pressure paths of the pressure regulating valves 14 and 15 is controlled by solenoids 16 and 17. More specifically, the solenoids 16 and 17 can control the hydraulic pressure according to the current value. Further, the pressure regulating valves 14 and 15 can control the hydraulic pressure applied to the friction elements 10 and 11 by switching the hydraulic pressure path by the hydraulic pressure controlled by the solenoids 16 and 17. Therefore, by controlling the solenoids 16 and 17 by the output signal of the TCU 18, the fluid pressure applied to the friction elements 10 and 11 can be changed, and the friction elements 10 and 11 can be engaged or released.

  The TCU 18 includes a throttle opening sensor signal for detecting the throttle opening of the engine, a signal from a vehicle speed sensor for detecting the vehicle speed, and a pressure switch connected to the hydraulic pressure paths 19 and 20 of the friction elements 10 and 11. 12 and 13 signals are respectively input. Here, the pressure switches 12 and 13 are switched from OFF to ON when the hydraulic pressure in the hydraulic pressure paths 19 and 20 reaches the switching set pressure. The TCU 18 executes a well-known control program based on the input information of the pressure switches 12 and 13 to perform shift control of the automatic transmission as usual, and further performs abnormality diagnosis during the shift control.

  First, normal gear shift control will be described. Based on the driving state such as the throttle opening and the vehicle speed, a gear stage suitable for the current driving state is obtained from a predetermined shift pattern. The description at the time of the shift at which the shift speed is switched to the preferred shift speed will be described using the examples of the friction elements 10 and 11.

  First, by switching the control valve 15 by controlling the solenoid 13 during shifting, the paths 20 and 23 are in communication with each other, the hydraulic pressure in the path 20 is reduced, and the friction element 11 is released. At this time, the pressure switch 13 switches from on to off when the hydraulic pressure in the path 20 falls below the switching set pressure, and outputs a signal to the TCU 18 indicating that the friction element 11 is moving toward release.

  On the other hand, by switching the adjustment valve 14 by controlling the solenoid 16, the paths 19 and 21 are in communication, the hydraulic pressure is supplied to the path 19, and the friction element 10 is engaged. At this time, the pressure switch 13 switches from off to on when the hydraulic pressure in the path 19 rises above the switching set pressure, and outputs a signal to the TCU 18 indicating that the friction element 11 is approaching engagement. As described above, the friction element 11 is released and the friction element 10 is engaged, so that the shift stage calculated based on the operation state such as the throttle opening degree and the vehicle speed is changed to a shift stage suitable for the current operation state. It can be shifted.

  Next, abnormality diagnosis of the automatic transmission when one friction element is released will be described with reference to the flowchart of FIG. When this flowchart is executed, it is possible to determine an abnormality of the automatic transmission in which the hydraulic pressure applied to the friction element does not decrease when one friction element is released.

  When this flowchart is executed, the process proceeds to step 1 (hereinafter referred to as “S1”), and a release command signal for releasing the friction element is output. The release command signal is output by the TCU 18 and the path of the pressure regulating valve 14 is switched by the solenoid 16. Thereby, the path | routes 19 and 23 will be in the state connected, and the hydraulic pressure added to a friction element falls. At this time, by switching the path of the pressure regulating valve 14 based on the release command signal, the hydraulic pressure applied to the friction element decreases so as to follow the release command signal.

  When the release command signal is output in S1, the process proceeds to S2, and whether or not the command value corresponding to the switching set pressure at which the pressure switch 12 switches from on to off (hereinafter referred to as “release judgment timing”) has been reached. to decide. When the release command signal reaches the release determination timing, the process proceeds to S3, and the abnormality diagnosis of the automatic transmission is performed by determining whether or not the friction element 10 is engaged based on the ON / OFF signal of the pressure switch 12. Do. When the automatic transmission is normal, when the release command signal reaches the release determination timing, the pressure switch 12 is switched from on to off, but the hydraulic pressure applied to the friction element does not decrease due to clogging of the drain pipe or the like. In this case, since the pressure switch 12 remains on, it is determined that the automatic transmission is abnormal. By executing this flowchart, when the friction element is released, it is possible to detect an abnormal state of the automatic transmission in which the hydraulic pressure applied to the friction element does not decrease due to clogging of the drain pipe or the like.

  In this flowchart, a preset command value is set as the release determination timing. However, the release determination timing may be corrected based on a past command value when the pressure switch is switched from on to off. More specifically, the average value of the past several points when the pressure switch is switched on / off may be used as the command value, or the pressure switch is turned on / off with respect to a preset command value. The deviation from the command signal at the time of switching may be calculated, and the command value set in advance may be corrected based on the deviation. Thereby, even when the switching setting pressure of the pressure switch changes due to deterioration over time or the like, the abnormality diagnosis of the automatic transmission can be appropriately performed.

  Further, since the pressure switch has a characteristic of switching between on and off within a certain range, it is preferable to perform the release determination timing set based on the characteristic of the pressure switch. That is, the abnormality diagnosis of the automatic transmission is performed within the range of the command signal corresponding to the maximum and minimum values of the pressure switch switching set pressure. As a result, it is possible to accurately determine abnormality of the automatic transmission.

  Next, abnormality diagnosis of the automatic transmission when this flowchart is executed will be described with reference to the time chart of FIG. First, at time t1, a release command signal for releasing the friction element 10 is output from the TCU 18. By outputting the release command signal, the path of the pressure regulating valve 14 is switched, and the paths 19 and 23 are in communication with each other, and the hydraulic pressure applied to the friction element is reduced based on the release command signal.

  When the release command signal reaches the release determination timing at time t2, whether or not the friction element 10 is released is determined based on the ON / OFF signal of the pressure switch 12. When the automatic transmission is normal, the hydraulic pressure in the hydraulic pressure path 19 decreases so as to follow the release command signal, so that the pressure switch 12 is switched from on to off. However, when the automatic transmission is abnormal, the pressure switch remains on because the hydraulic pressure in the hydraulic path 19 does not decrease due to clogging of the drain pipe or the like. Therefore, by detecting the ON / OFF signal of the pressure switch 12 when the release command signal reaches the release determination timing, the automatic transmission in which the hydraulic pressure applied to the friction element does not decrease due to an abnormality due to clogging of the drain pipe, etc. An abnormal state can be detected.

  Next, abnormality diagnosis when one friction element is engaged will be described with reference to the flowchart of FIG. As a result, when one friction element is engaged, it can be determined that the fluid pressure does not increase due to, for example, liquid leakage in the fluid pressure path connected to the friction element.

  When this flowchart is executed, the process proceeds to S4, and an engagement command signal for engaging the friction element is output. This engagement command signal is output by the TCU 18, and the path of the pressure regulating valve 14 is switched by the solenoid 16. As a result, the paths 19 and 21 are in communication with each other, and the pressure supplied from the pressure source increases the hydraulic pressure applied to the friction element. At this time, the hydraulic pressure applied to the friction element rises so as to follow the engagement command signal by switching the path of the pressure regulating valve 14 based on the engagement command signal.

  If an engagement command signal is output in S4, the process proceeds to S5, and whether the pressure switch 12 has reached a command value (hereinafter referred to as "engagement determination timing") corresponding to a switching set pressure that changes state from OFF to ON. Judge whether or not. When the engagement command signal reaches the engagement determination timing, the process proceeds to S6, and it is determined whether or not the friction element 10 is engaged based on the ON / OFF signal of the pressure switch 12, thereby determining the abnormality of the automatic transmission. Make a diagnosis.

  When the automatic transmission is normal, the hydraulic pressure in the hydraulic pressure path 19 increases so as to follow the engagement command signal, so that the pressure switch 12 is switched from OFF to ON. However, if an abnormality such as fluid leakage in the hydraulic pressure path occurs, the hydraulic pressure in the hydraulic pressure path 19 does not increase, so the pressure switch remains off and it is determined that an abnormality has occurred in the automatic transmission. Thereby, it is possible to detect an abnormal state of the automatic transmission in which the hydraulic pressure applied to the friction element does not increase. By executing this flowchart, when the friction element is engaged, it is possible to detect an abnormal state of the automatic transmission in which the hydraulic pressure applied to the friction element does not increase due to a cause such as liquid leakage in the hydraulic pressure path.

  In this flowchart, a preset command value is set as the engagement determination timing, but the engagement determination timing may be corrected based on a past command value when the pressure switch is switched from OFF to ON. More specifically, the command value may be an average value of several past command signals when the pressure switch is switched from OFF to ON, or the pressure switch is turned OFF with respect to a preset command value. It is also possible to calculate a deviation of the command value when switching from ON to ON and correct a preset command value by the deviation. Thereby, even when the switching setting pressure of the pressure switch changes due to deterioration over time or the like, the abnormality diagnosis of the automatic transmission can be appropriately performed. Further, since the pressure switch has a characteristic of switching between on and off within a certain range, it is preferable to perform it at an engagement determination timing set based on the characteristic of the pressure switch. As a result, it is possible to accurately determine abnormality of the automatic transmission.

  Next, abnormality diagnosis of the automatic transmission when this flowchart is executed will be described with reference to the time chart of FIG. First, at time t1, an engagement command signal for engaging the friction element 10 is output from the TCU 18. By outputting the engagement command signal, the path of the pressure regulating valve 14 is switched, and the paths 19 and 21 are in communication with each other, and the hydraulic pressure applied to the friction element increases based on the engagement command signal.

  When the engagement command signal reaches the engagement determination timing at time t2, whether or not the friction element 10 is engaged is determined based on the ON / OFF signal of the pressure switch 12. When the automatic transmission is normal, the hydraulic pressure in the hydraulic pressure path 19 increases so as to follow the engagement command signal, so that the pressure switch 12 is switched from OFF to ON. However, when the automatic transmission is normal, the pressure switch remains off because the fluid pressure in the fluid pressure path 19 does not increase due to fluid leakage or the like. Accordingly, by detecting the ON / OFF signal of the pressure switch 12 when the engagement command signal reaches the engagement determination timing, the friction due to the abnormality due to the liquid leakage of the hydraulic path connected to the friction element is caused. An abnormal state of the automatic transmission in which the hydraulic pressure applied to the element does not increase can be detected.

[Embodiment 2]
A case will be described in which the switching set pressure at which the pressure switch changes state between on and off is high as shown in FIG. FIG. 7 is a flowchart of abnormality diagnosis of the automatic transmission at the time of a shift in which two friction elements are engaged or released. Friction elements 10 and 11 are changed at the time of shifting. By executing this flowchart, it is possible to detect an abnormality in the automatic transmission in which the two friction elements are released simultaneously.

  When this flowchart is executed, the process proceeds to S10, and a release command signal for releasing the friction element is output. By switching the path of the pressure regulating valve 14 based on this release command signal, the hydraulic pressure applied to the friction element decreases so as to follow the release command signal. When the release command signal is output in S10, the process proceeds to S11 and an engagement command signal for engaging the friction element is output. By switching the path of the pressure regulating valve 14 based on the engagement command signal, the hydraulic pressure applied to the friction element increases so as to follow the engagement command signal.

  When the engagement command signal is output in S11, the process proceeds to S12, and it is determined whether or not the release command signal has reached the release determination timing. When the release command signal reaches the release determination timing, the process proceeds to S13, and an abnormality diagnosis of the automatic transmission is performed by determining whether or not the friction element 10 is released by the ON / OFF signal of the pressure switch 12. When the automatic transmission is normal, the hydraulic pressure in the hydraulic pressure path 19 decreases so as to follow the release command signal, so that the pressure switch 12 is switched from on to off. However, if an abnormality occurs due to clogging of the drain pipe or the like, the hydraulic pressure in the hydraulic pressure path 19 does not decrease, so the pressure switch remains on, and it is determined that an abnormality has occurred in the automatic transmission.

  If it is determined in S14 that the friction element 10 has been released, the abnormal provisional determination flag TFAIL is turned on in order to erroneously determine that the two friction elements have been released simultaneously. When the abnormal temporary determination flag TFAIL is turned on in S14, the process proceeds to S15, and it is determined whether or not the engagement command signal has reached the engagement determination timing. When the engagement command signal reaches the engagement determination timing, the process proceeds to S16, and it is determined whether or not the friction element 11 is released based on the ON / OFF signal of the pressure switch 13, thereby diagnosing the abnormality of the automatic transmission. I do. When the automatic transmission is normal, the hydraulic pressure in the hydraulic pressure path 20 increases so as to follow the engagement command signal, so that the pressure switch 13 is switched from OFF to ON. However, if an abnormality occurs due to fluid leakage of the passage fluid pressure, the fluid pressure in the fluid passage 20 does not increase, the pressure switch remains off, and it is determined that an abnormality has occurred in the automatic transmission. For this reason, if it is determined in S15 that the friction element is not engaged, the process proceeds to S16, where it is determined that the automatic transmission is abnormal, and the abnormality determination flag FAIL is turned on. Thus, if an operation such as stepping on the accelerator while the two friction elements are released at the same time is performed, the engine rotation speed may be abnormally increased.

  If it is determined that the friction element is engaged in S16, the process proceeds to S17, where it is determined that the gear shift has been normally performed, the abnormal temporary determination flag is turned off, and this flowchart is ended.

  By executing this flowchart, it is possible to detect an abnormality in the automatic transmission in which the two friction elements are released simultaneously. Further, the release determination timing and the engagement determination timing may be calculated as shown in the first embodiment.

  Next, the abnormality diagnosis of the automatic transmission when this flowchart is executed will be described with reference to the time chart of FIG. At time t1, a release command signal for releasing the friction element 10 is output from the TCU 18. Next, an engagement command signal for engaging the other friction element 11 is output from the TCU 18. When the release command signal is output, the hydraulic pressure in the hydraulic pressure path 19 is lowered by controlling the solenoid 16 and switching the hydraulic pressure path with the adjusting valve 14. When the engagement command signal is output, the hydraulic pressure in the hydraulic pressure path 20 is increased by controlling the solenoid 17 to switch the hydraulic pressure path of the regulating valve 15. As the hydraulic pressures in the hydraulic pressure paths 19 and 20 increase or decrease based on the command signals, the friction elements 10 and 11 are released and engaged.

  When the release command signal reaches the release determination timing at time t2, it is determined whether or not the friction element 10 is released by detecting the on / off state of the pressure switch 12. At this time, if the pressure switch 12 remains on, it is determined that there is an abnormality in the automatic transmission in which the hydraulic pressure does not decrease due to clogging of the drain pipe or the like. At this time, since there is a possibility that the two friction elements are simultaneously engaged with each other, an anti-failure measure for stopping the engagement of the friction elements 11 is performed. In addition, when the pressure switch is in the OFF state, there is a risk of erroneous determination that the two friction elements are in the released state at the same time. Turn on.

  Next, when the engagement command signal reaches the engagement determination timing at time t3, it is determined whether the friction element 11 is released by detecting the on / off state of the pressure switch 13. At this time, if the pressure switch 13 remains off, it is determined that there is an abnormality in the automatic transmission in which the hydraulic pressure does not increase due to the occurrence of liquid leakage in the hydraulic pressure path 20 or the like. In this case, the two friction elements are released at the same time, and if an operation such as stepping on the accelerator in such a state is performed, there is a possibility that the engine speed will rise abnormally and cause a failure. I do. As described above, the abnormality determination of the automatic transmission can be accurately performed by performing the abnormality determination by the combination of the pressure switches at the later determination timing.

[Embodiment 3]
A case will be described in which the switching set pressure at which the pressure switch is turned on and off is low as shown in FIG. FIG. 9 is a flowchart of abnormality diagnosis of the automatic transmission at the time of a shift in which two friction elements are engaged or released. Friction elements 10 and 11 are changed at the time of shifting. By executing this flowchart, it is possible to detect an abnormality in the automatic transmission in which the two friction elements are simultaneously engaged.

  When the switching setting pressure is low, it is determined that the friction element 11 is engaged in a state where it is determined that the friction element 10 is engaged. It will be judged. For this reason, when the switching set pressure is low, abnormality diagnosis of the automatic transmission is performed by the combination of pressure switches at the later timing in the time series, that is, at the release determination timing when the friction element 10 is released.

  When this flowchart is executed, the process proceeds to S20, and a release command signal for releasing the friction element is output. By switching the path of the pressure regulating valve 14 based on this release command signal, the hydraulic pressure applied to the friction element decreases so as to follow the release command signal. When the release command signal is output in S20, the process proceeds to S21 and an engagement command signal for engaging the friction element is output. By switching the path of the pressure regulating valve 14 based on the engagement command signal, the hydraulic pressure applied to the friction element increases so as to follow the engagement command signal.

  When the engagement command signal is output in S21, the process proceeds to S22, in which it is determined whether or not the engagement command signal has reached the engagement determination timing. When the engagement command signal reaches the engagement determination timing, the process proceeds to S23, and it is determined whether or not the friction element 11 is engaged based on the ON / OFF signal of the pressure switch 12, thereby diagnosing the abnormality of the automatic transmission. Do. When the automatic transmission is normal, the hydraulic pressure in the hydraulic pressure path 20 increases so as to follow the engagement command signal, so that the pressure switch 13 is switched from OFF to ON. However, if an abnormality occurs due to fluid leakage of the passage fluid pressure, the fluid pressure in the fluid passage 20 does not increase, the pressure switch remains off, and it is determined that an abnormality has occurred in the automatic transmission.

  If it is determined in S24 that the friction element 10 has been released, the abnormality temporary determination flag TFAIL is turned on in order to erroneously determine that the two friction elements are simultaneously engaged. When the abnormality temporary determination flag TFAIL is turned on in S14, the process proceeds to S25, in which it is determined whether or not the release command signal has reached the release determination timing. When the release command signal reaches the release determination timing, the process proceeds to S26, and an abnormality diagnosis of the automatic transmission is performed by determining whether or not the friction element 10 is released based on the ON / OFF signal of the pressure switch 12. . When the automatic transmission is normal, the hydraulic pressure in the hydraulic pressure path 19 decreases so as to follow the release command signal, so that the pressure switch 12 is switched from on to off. However, if an abnormality occurs due to clogging of the drain pipe or the like, the hydraulic pressure in the hydraulic pressure path 19 does not decrease, so the pressure switch remains on, and it is determined that an abnormality has occurred in the automatic transmission. Therefore, if it is determined in S25 that the friction element is not released, the process proceeds to S26, where it is determined that the automatic transmission is abnormal, and the abnormality determination flag FAIL is turned on. In this way, in the interlock state where the two friction elements are engaged at the same time, the friction element is dragged and heat is lost due to wear, and the durability of the friction element can be reduced. Take measures against failing automatic transmission.

  If it is determined that the friction element is engaged in S26, the process proceeds to S27, where it is determined that the gear shift has been normally performed, the abnormal temporary determination flag is turned off, and this flowchart is ended.

  By executing this flowchart, it is possible to detect an abnormality in the automatic transmission that enters the interlock state in which the two friction elements are simultaneously engaged. Further, the release determination timing and the engagement determination timing may be calculated as shown in the first embodiment.

  Next, abnormality diagnosis of the automatic transmission when this flowchart is executed will be described with reference to the time chart of FIG. At time t1, a release command signal for releasing the friction element 10 is output from the TCU 18. Next, an engagement command signal for engaging the other friction element 11 is output from the TCU 18. When the release command signal is output, the hydraulic pressure in the hydraulic pressure path 19 is reduced by controlling the soleroid 16 and switching the hydraulic pressure path with the regulating valve 14. When the engagement command signal is output, the hydraulic pressure of the hydraulic pressure path 20 is increased by controlling the soleroid 17 and switching the hydraulic pressure path of the regulating valve 15. As the hydraulic pressure in the hydraulic pressure paths 19 and 20 rises or falls based on the command signals, the friction elements 10 and 11 are engaged and released.

  When the engagement command signal reaches the engagement determination timing at time t2, it is determined whether or not the friction element 11 is engaged by detecting the on / off state of the pressure switch 13. At this time, if the pressure switch 13 remains off, it is determined that there is an abnormality in the automatic transmission in which the hydraulic pressure does not increase due to a liquid leak in the hydraulic pressure path or the like. At this time, since there is a possibility that the two friction elements may be released at the same time, a failure countermeasure for stopping the release of the friction element 10 is performed. In addition, when the pressure switch is in the ON state, there is a risk of erroneous determination that the two friction elements are in the interlocked state at the same time. Turn on the temporary judgment flag.

  Next, when the release command signal reaches the release determination timing at time t3, it is determined whether or not the friction element 10 is released by detecting the on / off state of the pressure switch 12. At this time, if the pressure switch 13 remains in the ON state, it is determined that the automatic transmission is in an abnormal state where the hydraulic pressure does not decrease due to a clogging of the drain pipe. In this case, the two friction elements are engaged at the same time, and the friction elements are dragged, resulting in heat loss and wear, which may reduce the durability of the friction elements. Do. As described above, the abnormality determination of the automatic transmission can be accurately performed by performing the abnormality determination by the combination of the pressure switches at the later determination timing.

[Embodiment 4]
A description will be given of abnormality diagnosis of the automatic transmission when the switching set pressure is set in the vicinity of the fluid pressure in the fluid pressure path when engaging and releasing each friction element as shown in FIG. In this case, since the determination timing at which the friction element is released and engaged is switched depending on the characteristics of the pressure switch, it may be erroneously determined that the automatic transmission is abnormal. For this reason, the abnormality diagnosis of the engagement or release of the friction element is performed at each determination timing, and the abnormality diagnosis based on the combination of whether the two friction elements are engaged or released is preferably performed at a later determination timing. As a result, it is possible to accurately determine abnormality of the automatic transmission.

  In the first to fourth embodiments, the switching setting pressure of the pressure switch varies depending on the fluid temperature of the fluid pressure path of each friction element. For this reason, by setting each judgment timing according to the liquid temperature of the hydraulic pressure path, even when the liquid temperature changes depending on the operation state or when the liquid temperature is low at the cold start, the automatic transmission is accurately Can be diagnosed.

  Further, in the abnormality diagnosis of the automatic transmission, an erroneous determination due to the abnormality of the pressure switch can be considered. For example, as an abnormality of the pressure switch, an abnormality due to disconnection of an electric circuit connecting the pressure switch and the TCU can be considered. Therefore, the abnormality of the pressure switch is diagnosed by detecting the voltage of the electric circuit.

It is sectional drawing of the friction element of an automatic transmission. It is a schematic block diagram of the hydraulic circuit of an automatic transmission. It is an automatic transmission abnormality diagnosis flowchart when one friction element releases. It is an automatic shift abnormality diagnosis time chart when one friction element releases. It is an automatic transmission abnormality diagnosis flowchart when one friction element engages. It is an automatic transmission abnormality diagnosis time chart when one friction element is engaged. It is a flowchart of abnormality diagnosis of automatic gear shift at the time of gear shift in which two friction elements are switched when the switching set pressure is high. It is a time chart of abnormality diagnosis of automatic gear shift at the time of gear shift in which two friction elements are switched when the switching set pressure is high. It is a flowchart of abnormality diagnosis of automatic gear shift at the time of gear shift in which two friction elements are switched when the switching set pressure is low. 6 is a time chart for diagnosing abnormality in automatic gear shifting at the time of gear shifting in which two friction elements are switched when the switching set pressure is low. It is a figure showing the characteristic of the switch setting pressure of a pressure switch.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Friction element 12 Pressure switch 14 Control valve 16 Solenoid 18 TCU
21 Hydraulic supply path

Claims (10)

State signal output means for outputting a state signal indicating whether the friction element is engaged or released based on a hydraulic pressure applied to the friction element of the automatic transmission;
Command signal output means for outputting a command signal for engaging and releasing the friction element;
In an automatic transmission comprising friction element control means for engaging and releasing the plurality of friction elements by individually controlling the hydraulic pressures of the plurality of friction elements by the command signal output means,
Command signal determining means for determining whether the friction element is engaged or released based on the status signal output by the status signal output means and the command signal of the command signal output means;
An abnormality diagnosis device for an automatic transmission, comprising: an abnormality diagnosis unit that determines an abnormal state of the automatic transmission based on the command signal determination unit. The command signal determining means uses the state signal output by the state signal output means when the command signal output by the command signal output means reaches a preset command value, and a friction element 2. The abnormality diagnosis device for an automatic transmission according to claim 1, wherein it is determined whether the gear is engaged or released. The said command value is set based on the said command signal when the said status signal output by the said status signal output means switches from one state to the other state. Automatic transmission abnormality diagnosis device. Command value correcting means for correcting the command value based on a past command signal when the status signal output by the status signal output means switches from one state to the other state. The abnormality diagnosis device for an automatic transmission according to any one of claims 2 to 3. The command value correction means corrects the command value by the command signal when the command signal for correcting the correction signal is a command signal when the abnormality diagnosis means determines that the command signal is abnormal. 5. The abnormality diagnosis device for an automatic transmission according to claim 4, wherein there is no abnormality. The abnormality diagnosis unit is configured to output the state signal output unit by the command signal determination unit, although the command signal output by the command signal output unit has reached a preset command value. 6. The automatic transmission abnormality diagnosis device according to claim 2, wherein when it is determined that the state signal is not switched, it is determined that the automatic transmission is abnormal. At the time of speed change in which one friction element is released by the friction element control means and the other friction element is engaged,
The timing at which the command signal output by the command signal output means for releasing the friction element reaches the command value, and the command signal output by the command signal output means for engaging the friction element are: At the later timing of reaching the command value, whichever is later, the state signal output by the state signal output means of the released friction element and the state signal output means of the friction element to be engaged The abnormality diagnosis device for an automatic transmission according to any one of claims 2 to 6, wherein an abnormality state of the automatic transmission is determined based on the outputted state signal. The friction element to be released based on the state signal output by the state signal output means of the friction element to be released and the state signal output by the state signal output means of the friction element to be engaged 8. The automatic transmission abnormality diagnosis device according to claim 7, wherein if it is determined that the friction elements to be engaged are simultaneously released, it is determined that the automatic transmission is abnormal. The released friction element based on the state signal output by the state signal output means of the released friction element and the state signal output by the state signal output means of the engaged friction element; 8. The abnormality diagnosis device for an automatic transmission according to claim 7, wherein if it is determined that the friction elements to be engaged are simultaneously engaged, it is determined that the automatic transmission is abnormal. 10. The automatic transmission according to claim 1, wherein the command signal output by the command signal output unit is a hydraulic pressure command signal for controlling a hydraulic pressure of the friction element. Abnormality diagnosis device.

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