Automatic Transmission Shift Fork Unrequested Fault Detection and Handling Method

Abstract

The present invention discloses a method for detecting and handling unrequested faults of a shift fork of an automatic transmission, comprising the following steps: S1, collecting and processing the shift fork displacement signal; S2, detecting whether the position of the current shift fork is in the neutral position. If the detection result is yes, it is concluded that there is no fault; S3, detecting whether the current shift fork displacement sensor reports an electrical fault. If the detection result is yes, it is concluded that there is a first unrequested fault of the shift fork, and the first unrequested fault of the shift fork is processed; S4, detecting whether the current shift fork has a requested action. If the current shift fork has a requested action, go to S5. If the current shift fork has no requested action, go to S6; S5, detecting whether the current shift fork displacement direction is consistent with the shift fork request direction; S6, detecting whether there are other shift fork requested actions. The present invention can classify and correspondingly handle the faults after detecting the unrequested faults of the shift fork.

Description

Technical Field

[0001] The present invention relates to the field of automotive automatic transmissions, and particularly to a method for detecting and handling unrequested faults of shift forks for dual-clutch automatic transmissions and hybrid transmissions based on dual clutches. Background Art

[0002] As the name implies, a dual-clutch transmission has two clutches. On the basis of a traditional manual transmission, two clutches, a clutch actuator, a shift actuator, an electronic controller, and sensors are added. The electronic controller controls the shift actuator and the clutch actuator to replace manual shifting by humans and the operation of stepping on the clutch to achieve automatic shifting of the transmission. The precise control of the shift actuator by the electronic control unit is very important for a DCT transmission and will affect the power performance, comfort, and economy of the whole vehicle.

[0003] The shift assembly system includes a shift actuator, a shift fork, a synchronizer, a shift fork position sensor, etc. The shift fork position includes the in-gear position, the neutral position, the transition position, and the in-gear limit position. The in-gear position is when the shift fork position can make the synchronizer sleeve and the gear ring have a certain reverse taper engagement amount; the in-gear limit position is when the shift fork position pushes the synchronizer sleeve to the end face of the sleeve limit; the neutral position is when the shift fork position does not axially force the synchronizer slider; the transition position is when the shift fork position exceeds the neutral position and has not reached the in-gear position yet.

[0004] Requested gear Corresponding transmission shaft Corresponding transmission fork First reversing valve Second reversing valve First pressure valve Second pressure valve 1 First shaft First fork Closed Closed Forward force Reverse force 2 First shaft First fork Closed Closed Reverse force Forward force 3 First shaft Second fork Closed Open Forward force Reverse force 4 First shaft Second fork Closed Open Reverse force Forward force 5 Second shaft Third fork Open Closed Forward force Reverse force 6 Second shaft Third fork Open Closed Reverse force Forward force 7 Second shaft Fourth fork Open Open Forward force Reverse force 8 Second shaft Fourth fork Open Open Reverse force Forward force

[0005] Table 1

[0006] If the first gear is not requested to be engaged at this time, but the position of the first shift fork moves in the direction of the first gear and exceeds the neutral position, then an unrequested fault occurs in the first shift fork. There are many reasons for the unrequested fault of the first shift fork. For example, the displacement of the shift fork is offset due to an electrical fault of the shift fork displacement sensor, or the solenoid valve is stuck, resulting in gear shifting disorder and causing a fault. If not handled, it may cause the first gear to be engaged, resulting in a disorder of the transmission system, affecting the normal use of the whole vehicle and causing damage. Therefore, it is necessary to detect and handle the position of each shift fork. At the same time, in order to facilitate after-sales personnel to analyze this fault, the causes of this fault are classified and stored in the TCU, and corresponding handling measures are taken for different fault causes. Summary of the Invention

[0007] The present invention provides a method for detecting and handling faults of shift forks of a dual-clutch transmission. The present invention can classify and handle the faults after detecting unrequested faults of the shift forks.

[0008] The technical solutions to solve the above problems are as follows:

[0009] Detection and handling method for unrequested faults of an automatic transmission shift fork, comprising the following steps:

[0010] S1, collect and process the shift fork displacement signal;

[0011] S2, detect whether the current position of the shift fork is in the neutral position. If the detection result is yes, it is concluded that there is no fault. If the detection result is no, go to S3;

[0012] S3, detect whether the current shift fork displacement sensor reports an electrical fault. If the detection result is yes, it is concluded that there is a first unrequested fault of the shift fork, and handle the first unrequested fault of the shift fork; if the detection result is no, go to S4;

[0013] S4, detect whether the current shift fork has a requested action. If the current shift fork has a requested action, go to S5. If the current shift fork has no requested action, go to S6;

[0014] S5, detect whether the current shift fork displacement direction is consistent with the shift fork request direction. If the detection result is yes, it is concluded that there is no fault; if the detection result is no, it is concluded that there is a second unrequested fault of the shift fork, and handle the second unrequested fault of the shift fork;

[0015] S6, detect whether there is a requested action of other shift forks. If the detection result is yes, it is concluded that there is a third unrequested fault of the shift fork, and handle the third unrequested fault of the shift fork; if the detection result is no, it is concluded that there is a fourth unrequested fault of the shift fork, and handle the fourth unrequested fault of the shift fork.

[0016] Further, the collection and processing of the shift fork displacement signal in S1 is as follows: the shift fork displacement sensor collects a voltage signal and inputs it into the transmission control unit TCU. The TCU converts the voltage value into a millimeter value according to the corresponding physical characteristics of the shift fork sensor.

[0017] Further, the shift fork positions in S2 include the in-gear position, the neutral position, the transition position, and the in-gear limit position. Among them, the in-gear position is when the shift fork position can make the synchronizer sleeve and the engaging teeth of the gear ring have an engagement amount; the neutral position is when the shift fork position does not axially stress the synchronizer slider; the transition position is when the shift fork position exceeds the neutral position and has not yet reached the in-gear position; the in-gear limit position is when the shift fork position pushes the synchronizer sleeve to the end face of the sleeve limit.

[0018] Further, the handling method for the second unrequested fault of the shift fork is as follows:

[0019] S1102, allow the current shift fork to continue to move in the opposite direction until the reverse gear is engaged;

[0020] S1103, after the current shift fork engages the reverse gear, flush the reverse valve.

[0021] S1104, request gear shifting again;

[0022] S1105, if the current shift fork displacement direction is the same as the requested gear direction, and it is detected whether there is still the unrequested second fault. If there is no unrequested second fault of the shift fork, then enter S1106; if there is an unrequested second fault of the shift fork, then enter S1107;

[0023] S1106, after the reverse solenoid valve gets stuck, flush it to normal through the flushing strategy, and the transmission fault is not displayed on the instrument panel;

[0024] S1107, cancel all reverse force requests for gear shifting, report the reverse solenoid valve failure fault at the same time, and send the transmission fault to the instrument panel.

[0025] Furthermore, the handling method for the third fault not requested by the shift fork is as follows:

[0026] S1402, close the pressure valve request and prohibit the pressure valve from outputting pressure;

[0027] S1403, flush the reversing valve;

[0028] S1404, request gear shifting for other gears again;

[0029] S1405, detect whether there is still the third fault not requested by the shift fork. If the detection result is no, then enter S1406; if the detection result is yes, then enter S1407;

[0030] S1406, after the reversing solenoid valve gets stuck, flush it to normal through the flushing strategy, and the transmission fault is not displayed on the instrument panel;

[0031] S1407, cancel the gear request command, report the reversing solenoid valve failure fault at the same time, and send the transmission fault to the instrument panel.

[0032] Furthermore, the handling method for the fourth fault not requested by the shift fork is as follows:

[0033] S1602, request to return the current shift fork to the neutral position;

[0034] S1603, accumulate the number of times of the fourth fault not requested by the shift fork;

[0035] S1604, judge whether the number of times of the fourth fault not requested by the shift fork is greater than the set threshold;

[0036] S1605, if it is greater than the set threshold, the instrument displays the transmission fault and prompts for maintenance;

[0037] S1606. If it is less than the set threshold, the instrument does not display the transmission fault.

[0038] During the operation of the transmission, the present invention detects the position of each shift fork at any time and anywhere, classifies and correspondingly processes the faults after detecting that the shift fork has an unrequested fault, avoiding functional problems such as incorrect gear shifting and inability to shift gears in the transmission system, so as to improve the accuracy, stability and reliability of gear shifting of the dual-clutch transmission system. At the same time, the fault type is saved in the TCU, which is convenient for after-sales personnel to quickly lock the cause of the fault during the repair of the whole vehicle. Brief Description of the Drawings

[0039] Figure 1 is the flow chart of the present invention;

[0040] Figure 2 is the flow chart of the second fault handling for the unrequested shift fork;

[0041] Figure 3 is the flow chart of the third fault handling for the unrequested shift fork;

[0042] Figure 4 is the flow chart of the fourth fault handling for the unrequested shift fork. Detailed Embodiment

[0043] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "lateral", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as limiting the protection scope of the present invention.

[0044] A method for detecting and handling unrequested faults of an automatic transmission shift fork includes the following steps:

[0045] S1. Collect and process the shift fork displacement signal. Preferably, the collection and processing of the shift fork displacement signal in S1 are as follows: The shift fork displacement sensor collects the voltage signal and inputs it into the transmission control unit TCU. The TCU converts the voltage value into a millimeter value according to the corresponding physical characteristics of the shift fork sensor.

[0046] There is a position sensor on each shift fork to obtain the corresponding shift fork position. The TCU sampling period for the shift fork position is 10 ms. The TCU collects the signal of the shift fork position sensor as a voltage value, and processes the voltage signal into the shift fork position through the corresponding relationship between the sensor voltage value and the position.

[0047] S2. Detect whether the current shift fork is in the neutral position. If the detection result is yes, it is concluded that there is no fault. If the detection result is no, go to S3.

[0048] Preferably, the shift fork positions in S2 include the in-gear position, the neutral position, the transition position, and the in-gear limit position. Among them, the in-gear position means that the current shift fork position can make the synchronizer sleeve and the engaging teeth of the gear ring have an engagement amount; the neutral position means that the current shift fork position does not axially force the synchronizer slider; the transition position means that the shift fork position exceeds the neutral position and has not reached the in-gear position yet; the in-gear limit position means that the current shift fork position pushes the synchronizer sleeve to the limit end face of the sleeve.

[0049] S3. Detect whether the current shift fork displacement sensor reports an electrical fault. If the detection result is yes, it is concluded that there is a first fault of the unrequested shift fork, and process the first fault of the unrequested shift fork. If the detection result is no, go to S4;

[0050] First, when the current shift fork is not in the neutral position, determine whether the current shift fork displacement sensor reports an electrical fault. The current shift fork unrequested fault caused by the displacement sensor fault is defined as the first fault of the unrequested shift fork (such as Figure 1 S31 in), and store it in the NVM. For the first fault of the unrequested shift fork, the processing method is to directly report a transmission fault (such as Figure 1 S32 in).

[0051] S4. Detect whether the current shift fork has a requested action. If the current shift fork has a requested action, go to S5. If the current shift fork has no requested action, go to S6.

[0052] That is, after it is detected that the current monitored shift fork is not in the neutral position and the shift fork displacement sensor does not report an electrical fault, determine whether the TCU requests the current shift fork to shift gears. If the TCU requests the current shift fork gear, go to S5. If the current shift fork has no requested action, go to S6.

[0053] S5. Detect whether the current shift fork displacement direction is consistent with the shift fork request direction. If the detection result is yes, it means that the shift fork displacement is moving according to the request instruction, and it is concluded that there is no fault, that is, the current shift fork does not have an unrequested fault (such as Figure 1 S50 in), and continue to monitor the current shift fork. If the detection result is no, it is concluded that there is a second unrequested fault, that is, if the shift fork displacement direction and the requested gear displacement are inconsistent at this time, and the time exceeds the set threshold, it is judged that there is a second unrequested fault of the shift fork (such as Figure 1 S51 in), store the second unrequested fault of the shift fork in the NVM, and process the second unrequested fault of the shift fork (such as Figure 1 S52 in).

[0054] For the second unrequested fault of the shift fork, this fault occurs because the reverse pressure valve fails, and the requested reverse force is inconsistent with the actual reverse force, resulting in the reverse force being greater than the forward force, pushing the shift fork to move in the opposite direction. As Figure 2 , the processing method for the second unrequested fault of the shift fork is as follows:

[0055] S1102, Allow the current shift fork to continue moving in the opposite direction until the reverse gear is engaged;

[0056] S1103, After the current shift fork engages the reverse gear, flush the reverse valve;

[0057] S1104, Request to engage the gear again;

[0058] S1105, If the displacement direction of the current shift fork is the same as the requested gear direction, and it is detected whether there is still the second unrequested fault of the shift fork. If there is no second unrequested fault, enter S1106; if there is a second unrequested fault of the shift fork, enter S1107;

[0059] S1106, After the reverse solenoid valve is stuck, flush it to normal through the flushing strategy, and the transmission fault is not displayed on the instrument panel;

[0060] S1107, If the moving direction of the current shift fork is inconsistent with the requested gear direction, and there is a second unrequested fault of the shift fork, it means that the flushing strategy still cannot make the reverse solenoid valve return to normal. Cancel all requests for reverse force for engaging the gear, report the failure of the reverse solenoid valve at the same time, and send a transmission fault to the instrument panel.

[0061] S6, Detect whether there are other requests for the shift fork to act. If the detection result is yes, it is concluded that there is a third unrequested fault of the shift fork (such as Figure 1 S60 in), store the third unrequested fault of the shift fork in NVM, and process the third unrequested fault of the shift fork (such as Figure 1 S61 in); if the detection result is no, it is concluded that there is a fourth unrequested fault of the shift fork (such as Figure 1 S62 in), and process the fourth unrequested fault of the shift fork (such as Figure 1 S63 in).

[0062] Preferably, the TCU does not request the current shift fork to engage the gear, but at this time the current shift fork position is not in the neutral position. Determine whether there are other shift forks requesting to act. If there are, enter S60; if there are not, enter S62.

[0063] For the third unrequested fault of the shift fork, this fault occurs because the reversing valve fails, and the actual state of the reversing valve does not match the requested state, resulting in the misalignment of the oil circuit on and off. When requesting other shift forks to engage the gear, the current shift fork is caused to move. The processing method for the unrequested third fault is as follows:

[0064] S1402, Request to close the pressure valve, prohibiting the pressure valve from outputting pressure;

[0065] S1403, Flush the reversing valve;

[0066] S1404, Request to shift to other gears again;

[0067] S1405, Detect whether there is still the unrequested third fault. If the detection result is no, enter S1406; if the detection result is yes, enter S1407;

[0068] S1406, If the reversing solenoid valve is stuck, flush it to normal through the flushing strategy, and the transmission fault is not displayed on the instrument panel;

[0069] S1407, If there is an unrequested third fault in the shift fork, it means that the flushing strategy still cannot make the reversing solenoid valve return to normal. To ensure the safety of the driver, cancel the gear request command, report the failure of the reversing solenoid valve at the same time, and send a transmission fault to the instrument panel.

[0070] When no shift fork has a gear request action, and the current shift fork displacement moves, this fault is defined as the unrequested fourth fault of the shift fork and stored in NVM. The processing method for the unrequested fourth fault is as follows:

[0071] S1602, Request to return the current shift fork to neutral;

[0072] S1603, Accumulate the number of times the unrequested fourth fault of the shift fork occurs;

[0073] S1604, Determine whether the number of times the unrequested fourth fault of the shift fork is greater than the set threshold;

[0074] S1605, If it is greater than the set threshold, the instrument displays a transmission fault, prompting the driver or customer to go to the 4S shop for repair;

[0075] S1606, If it is less than the set threshold, the instrument does not display a transmission fault.

[0076] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be described in more detail below with reference to the accompanying drawings in the embodiments of the present invention. The described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. The embodiments described below by referring to the accompanying drawings are exemplary and are intended to explain the present invention, and should not be simply construed as a limitation of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative efforts fall within the scope of protection of the present invention.

Claims

1. A method for detecting and handling unrequested faults of a shift fork of an automatic transmission, characterized in that: The steps include: S1. Collect and process the shift fork displacement signal; S2. Detect whether the current position of the shift fork is in the neutral position. If the detection result is yes, it is concluded that there is no fault. If the detection result is no, then go to S3; S3. Detect whether the current shift fork displacement sensor reports an electrical fault. If the detection result is yes, it is concluded that there is a first fault that the shift fork does not request, and process the first fault that the shift fork does not request; If the detection result is no, then go to S4; S4. Detect whether the current shift fork has a requested action. If the current shift fork has a requested action, then go to S5. If the current shift fork has no requested action, then go to S6; S5. Detect whether the current shift fork displacement direction is consistent with the shift fork request direction. If the detection result is yes, it is concluded that there is no fault; If the detection result is no, it is concluded that there is a second fault that the shift fork does not request, and process the second fault that the shift fork does not request. The processing method for the second fault that the shift fork does not request is: S1102. Allow the current shift fork to continue moving in the opposite direction until the reverse gear is engaged; S1103. After the current shift fork engages the reverse gear, flush the reverse valve; S1104. Request to shift gears again; S1105. If the current shift fork displacement direction is consistent with the requested gear direction, and detect whether there is still the second fault that is not requested. If there is no second fault that the shift fork does not request, then go to S1106; if there is a second fault that the shift fork does not request, then go to S1107; S1106. After the reverse solenoid valve is stuck, flush it to normal through the flushing strategy, and the dashboard does not display a transmission fault; S1107. Cancel all reverse force requests for shifting gears, and at the same time report a reverse solenoid valve failure fault and send a transmission fault to the dashboard; S6. Detect whether there is a requested action of other shift forks. If the detection result is yes, it is concluded that there is a third fault that the shift fork does not request, and process the third fault that the shift fork does not request; If the detection result is no, it is concluded that there is a fourth fault that the shift fork does not request, and process the fourth fault that the shift fork does not request.

2. The method for detecting and handling an unrequested failure of a shift fork of an automatic transmission according to claim 1, characterized in that: The collection and processing of the shift fork displacement signal in S1 are as follows: The shift fork displacement sensor collects the voltage signal and inputs it into the transmission control unit TCU. The TCU converts the voltage value into a millimeter value according to the corresponding physical characteristics of the shift fork displacement sensor.

3. The detection and processing method for the unrequested failure of the shift fork of an automatic transmission according to claim 1, characterized in that: The shift fork positions in S2 include the in-gear position, the neutral position, the transition position, and the in-gear limit position. Among them, the in-gear position is when the shift fork position can make the synchronizer sleeve and the engaging teeth of the gear ring have an engagement amount; the neutral position is when the shift fork position does not make the synchronizer slider axially stressed; the transition position is when the shift fork position exceeds the neutral position and has not reached the in-gear position; the in-gear limit position is when the shift fork position pushes the synchronizer sleeve to the limit end face of the sleeve.

4. The detection and processing method for the unrequested failure of the shift fork of an automatic transmission according to claim 1, characterized in that, The processing method for the third fault that the shift fork does not request is: S1402. Close the pressure valve request and prohibit the pressure valve from outputting pressure; S1403. Flush the reversing valve; S1404. Request to shift to other gears again; S1405, Detect whether there is still a third fault not requested by the shift fork. If the detection result is no, proceed to S1406; if the detection result is yes, proceed to S1407; S1406, If the reversing solenoid valve is stuck, flush it to normal through the flushing strategy, and the transmission fault is not displayed on the instrument panel; S1407, Cancel the gear request command, report the failure of the reversing solenoid valve, and send a transmission fault to the instrument panel.

5. The detection and processing method for the unrequested fault of the shift fork of an automatic transmission according to claim 1, wherein The processing method for the fourth fault not requested by the shift fork is as follows: S1602, Request to return the current shift fork to neutral; S1603, Accumulate the number of occurrences of the fourth fault where the shift fork is not requested; S1604, Determine whether the number of occurrences of the fourth fault where the shift fork is not requested is greater than the set threshold; S1605, If it is greater than the set threshold, the instrument displays a transmission fault and prompts for repair; S1606, If it is less than the set threshold, the instrument does not display a transmission fault.

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