Automatic gearbox shifting fork blocking fault detection method

Abstract

The invention relates to the field of automatic transmission vehicle control, in particular to an automatic transmission shifting fork gear clamping fault detection method, which comprises the following steps of: detecting the gear engaging process of each target gear of a vehicle automatic transmission in real time to obtain a theoretical shifting fork gear clamping fault judgment result; further judgment is carried out on the preliminarily obtained shifting fork gear clamping fault judgment result based on the theory, so that a driver can accurately and timely find out the shifting fork gear clamping fault of the automatic gearbox finally, safety accidents are avoided, after-sales personnel can conveniently and rapidly lock fault reasons in the vehicle maintenance process, and the maintenance efficiency is improved. And meanwhile, the contingency of fault detection is avoided, and the detection accuracy of the gear clamping fault of the shifting fork of the automatic gearbox is improved.

Description

Technical Field

[0001] The invention relates to the field of automatic transmission vehicle control, and in particular to a method for detecting a shift fork stuck fault of an automatic transmission. Background Art

[0002] Compared with manual transmission vehicles, automatic transmission vehicles greatly reduce the frequency of manual operations and gear shifting by the driver, greatly reduce the driver's workload, and are simple, convenient and fast to operate. Therefore, automatic transmission vehicles have been increasingly promoted and used.

[0003] In automatic transmission vehicles, the shift fork in the automatic transmission plays a vital role. When the shift fork is switched to the target gear, if the clutch is in the engaged state, the automatic transmission will output power according to the transmission ratio of the target gear to drive the car; when the shift fork is switched to neutral, the automatic transmission will cut off the output power of the engine to slow down or stop the vehicle.

[0004] At present, the gear sticking phenomenon often occurs during the driving of automatic transmission vehicles. Not only can the shift fork fail to reach the target gear quickly and accurately as expected by the driver, but the shift fork becomes stuck and repeated gear shifting fails to make the shift fork reach the correct position. The automatic transmission cannot output power according to the transmission ratio of the target gear.

[0005] This jamming phenomenon will, on the one hand, cause deterioration in fuel economy, impact, jerking and noise, and on the other hand, will cause insufficient vehicle power and reduced power system response speed, which will easily affect the use of the vehicle's functions, seriously affect the driving experience, and even lead to safety accidents. Accurate and timely detection of automatic transmission fork gear jam failure is a prerequisite for reducing the accident rate.

[0006] Therefore, during the driving process of an automatic transmission vehicle, how to enable the control unit of the automatic transmission to accurately and timely detect the shift fork gear jam fault has always been a problem to be solved urgently in the field. Summary of the invention

[0007] The purpose of the present invention is to provide an automatic transmission shift fork stuck fault detection method to address the corresponding deficiencies in the prior art, which can accurately and timely detect the automatic transmission shift fork gear stuck fault, facilitate the subsequent analysis and solution of the automatic transmission shift fork stuck fault when shifting gears, so as to improve the smoothness of the shift fork gear shifting and the driving performance of the whole vehicle, and reduce the probability of accidents.

[0008] The objective of the present invention is achieved by adopting the following scheme:

[0009] A method for detecting a shift fork stuck fault in an automatic transmission comprises the following steps:

[0010] 1) Setting a first threshold and a second threshold to determine a theoretical fault of an automatic transmission shift fork being stuck;

[0011] 2) Determine whether the current vehicle driving state is a supporting shift state during the detection cycle, and determine whether there is a theoretical fault of the automatic transmission fork stuck in the following ways:

[0012] 2-1) If the driving state of the whole vehicle is a non-supported shifting state, it is determined whether there is a theoretical shift fork stuck fault in the automatic transmission according to the relationship between the "position of the target gear shift fork", "planned gear shift fork", "shift fork control state", "shift fork movement action sub-state" and "number of repeated gear shifting times" of the automatic transmission of the vehicle and the first threshold value;

[0013] 2-2) If the driving state of the whole vehicle is in the supporting shifting state, it is judged whether there is a theoretical shift fork jamming fault in the automatic transmission based on the relationship between the "target gear fork position", "shift fork planned gear position", "shift fork control state", "shift fork movement action sub-state" and "number of repeated gear shifting times" of the automatic transmission of the vehicle and the second threshold.

[0014] Preferably, in step 2-1), if the relationship between the "target gear fork position", "fork planned gear position", "fork control state", "fork movement action sub-state", and "number of repeated gear shifting times" of the vehicle's automatic transmission and the first threshold value simultaneously satisfies the following conditions, then the vehicle's automatic transmission has a theoretical fork stuck fault:

[0015] 2-1-1) The target gear shift fork is not in the neutral position;

[0016] 2-1-2) The gear position of the shift fork is the target gear position;

[0017] 2-1-3) The shift fork control state is the gear engaging state;

[0018] 2-1-4) The shift fork movement action sub-state is the secondary gear engagement state;

[0019] 2-1-5) The number of repeated gear shifting times is greater than the first threshold.

[0020] Preferably, in step 2-2), if the relationship between the "target gear fork position", "fork planned gear position", "fork control state", "fork movement action sub-state", and "number of repeated gear shifting times" of the vehicle's automatic transmission and the second threshold value simultaneously satisfies the following conditions, then the vehicle's automatic transmission has a theoretical fork stuck fault:

[0021] 2-2-1) The target gear shift fork is not in the neutral position;

[0022] 2-2-2) The gear position of the shift fork is the target gear position;

[0023] 2-2-3) The shift fork control state is the gear engaging state;

[0024] 2-2-4) The shift fork movement action sub-state is the secondary gear engagement state;

[0025] 2-2-5) The number of repeated gear shifting is ≥ the second threshold.

[0026] Preferably, a third threshold, a reset mark C, a set mark D, and a target gear engagement block counter are further provided, and the third threshold, the reset mark C, the set mark D, and the target gear engagement block counter are used to judge the automatic transmission fork stuck theoretical fault within the detection period, and the specific method is as follows:

[0027] 3-1) When the automatic transmission control unit is powered on, the variable corresponding to the target gear engagement block counter reading is initialized;

[0028] 3-2) determining the shift fork position corresponding to the current target gear position within the detection cycle, and determining the change state of the current reset mark C according to the shift fork position corresponding to the current target gear position;

[0029] 3-3) According to the change state of the reset flag C, the reading of the target gear engagement block counter is calculated or processed in the following manner:

[0030] If the current value of the reset flag C changes from "non-1" to "1", the target gear engagement blocking counter reading is cleared;

[0031] If the current value of the reset flag C does not change from "non-1" to "1", the change state of the set flag D is determined according to the "fork planned gear position", "fork control state", "fork movement action sub-state" of the automatic transmission during the detection cycle, and the relationship between the "number of repeated gear shifting times" and the first threshold and the second threshold, and according to the change state of the set flag D, the reading of the target gear position gear shifting block counter is calculated or processed in the following manner:

[0032] ① If the value of the current set flag D changes from "0" to "non-0", the reading of the target gear engagement block counter will increase automatically;

[0033] ② If the value of the current set flag D does not change from "0" to "non-0", the reading of the target gear engagement block counter remains unchanged;

[0034] 3-4) Repeat steps 3-2) to 3-3) within the detection cycle until the detection cycle ends, and compare the target gear position engagement block counter reading with the third threshold value at this time to determine whether there is a theoretical shift fork stuck fault in the automatic transmission:

[0035] 3-4-1) If the target gear engagement resistance counter reading is ≤ the third threshold, there is no theoretical shift fork jamming fault in the automatic transmission;

[0036] 3-4-2) If the target gear shifting resistance counter reading is greater than the third threshold, there is a theoretical shift fork jamming fault in the automatic transmission.

[0037] Preferably, in step 3-2), the specific method of determining the change state of the current reset mark C by the fork position corresponding to the current target gear position is as follows:

[0038] 3-2-1) Determine whether the shift fork position corresponding to the current target gear position satisfies the following conditions at the same time:

[0039] ① The shift fork corresponding to the current target gear position is not in the current target gear position during the previous gearbox control unit operation cycle;

[0040] ② The shift fork corresponding to the current target gear position is already in the current target gear position during the current gearbox control unit operation cycle;

[0041] 3-2-2) According to the judgment result of step 3-2-1), the reset flag C is processed in the following manner:

[0042] If the shift fork position corresponding to the current target gear position satisfies the above conditions at the same time, the reset flag C is set to 1;

[0043] If the shift fork position corresponding to the current target gear does not simultaneously meet the above conditions, the reset flag C is set to 0.

[0044] Preferably, in step 3-3), the specific manner of determining the change state of the setting flag D according to the relationship between the "shift fork planned gear position", "shift fork control state", "shift fork movement action sub-state" and "number of repeated gear shifting times" of the automatic transmission and the first threshold and the second threshold within the detection cycle is as follows:

[0045] 3-3-1) Determine whether the current state of the automatic transmission satisfies the following conditions at the same time, and determine the change state of the setting flag D corresponding to the current transmission control unit operation cycle in the following manner:

[0046] ①The shift fork control state is in gear;

[0047] ② The shift fork moving action sub-state is the secondary gear engaging state;

[0048] ③The gear position planned for the shift fork is the target gear position;

[0049] 3-3-2) If the current state of the automatic transmission satisfies the above conditions at the same time, the change state of the setting flag D is judged according to the vehicle driving state within the current transmission control unit operation cycle:

[0050] If the vehicle driving state in the current gearbox control unit operation cycle is not a supporting shift state, and the number of repeated gear shifting times is greater than the first threshold, the setting flag D is set to 1;

[0051] If the vehicle driving state in the current gearbox control unit operation cycle is the supporting shift state, and the number of repeated gear shifting is ≥ the second threshold, the setting flag D is set to 1;

[0052] 3-3-3) If the current state of the automatic transmission does not meet the above conditions at the same time, the change state of the setting flag D is determined according to the following conditions:

[0053] ① The gear position corresponding to the previous gearbox control unit operation cycle is not equal to the gear position corresponding to the current gearbox control unit operation cycle;

[0054] ② The gear position corresponding to the current gearbox control unit operation cycle is not neutral;

[0055] ③ The value of the setting flag D in the previous gearbox control unit operation cycle is 1;

[0056] If the current state of the automatic transmission meets the above conditions at the same time, the set flag D is set to 0;

[0057] If the current state of the automatic transmission does not meet the above conditions at the same time, the setting flag D remains unchanged.

[0058] Preferably, a shift fork target gear position stuck error counter and a fault detection threshold are further provided. Each time a shift fork stuck theoretical fault is determined to exist in the automatic transmission during the detection cycle, the shift fork target gear position stuck error counter is incremented until the detection cycle ends. The shift fork target gear position stuck error counter and the fault detection threshold are compared at this time to determine whether the automatic transmission has a shift fork stuck actual fault:

[0059] If the shift fork target gear stuck error counter is greater than the fault detection threshold, the automatic transmission has a shift fork stuck actual fault;

[0060] If the shift fork target gear stuck error counter ≤ the fault detection threshold, there is no actual shift fork stuck fault in the automatic transmission.

[0061] Preferably, the fault detection threshold is obtained by whole vehicle test calibration.

[0062] Preferably, the first threshold and the second threshold are both obtained by whole vehicle experiment calibration.

[0063] Preferably, the third threshold is obtained by whole vehicle test calibration.

[0064] The beneficial effects of the present invention are as follows:

[0065] ① The present invention can accurately and timely detect the automatic transmission fork gear jamming fault by real-time detection of the gear shifting process of each target gear of the vehicle's automatic transmission, thereby avoiding the occurrence of safety accidents and facilitating after-sales personnel to quickly identify the cause of the fault during vehicle maintenance;

[0066] ② The present invention further judges the theoretical fault of the shift fork stuck by setting a fault detection threshold, thereby avoiding the randomness of fault detection and improving the detection accuracy of the automatic transmission shift fork gear stuck fault.

[0067] ③ The present invention does not simply make a judgment and then arbitrarily give a result, but adopts different threshold values, different judgment methods, and different calculation processes to verify each other in order to maximize the accuracy of judging the fork jam fault.

[0068] Glossary

[0069] Shifting gears: Also called "shifting gears operation", it means that when the shift fork moves from the current gear to the target gear, the shift fork will push the synchronizer or directly push the gear to make it engage or disengage with the corresponding gear shaft to achieve the switching of different gears, thereby transmitting power and driving the vehicle forward or backward. For example, when the shift fork is shifted from the first gear to the second gear, the shift fork moves to separate the first gear that was originally engaged, and at the same time pushes the second gear to engage with the shaft to complete the gear change.

[0070] Shift fork target gear stuck error counter: a counter specially provided in the present invention for recording the theoretical number of shift fork stuck faults.

[0071] Target gear engagement block counter: usually refers to a technical indicator or monitoring tool in a car or other mechanical transmission system. In the present invention, it refers to a software function module or a hardware function module for counting the number of blockages when attempting to engage the target gear.

[0072] Secondary gear shifting state: in the present invention, it refers to the situation that the automatic transmission performs a gear shifting operation once and finds that the gear shifting operation is unsuccessful, and tries to shift gears again in a short period of time. Secondary gear shifting, tertiary gear shifting, etc. are collectively referred to as repeated gear shifting.

[0073] The number of repeated gear shifting: in the present invention, refers to the cumulative number of gear shifting operations that are performed again within a short period of time after the first gear shifting operation is completed and it is found that the gear shifting is unsuccessful during the driving process of the vehicle.

[0074] Non-1: In the present invention, it means that the value of the variable is not 1.

[0075] Non-zero: In the present invention, it means that the value of a variable is not zero. BRIEF DESCRIPTION OF THE DRAWINGS

[0076] Figure 1 is a flow chart of the present invention;

[0077] Figure 2 It is a schematic diagram of a flow chart of an embodiment of the present invention;

[0078] Figure 3 Schematic diagram of a flow chart of a method for calculating a reset flag C in an embodiment of the present invention;

[0079] Figure 4 Schematic diagram of the flow of the method for calculating the setting flag D in an embodiment of the present invention. DETAILED DESCRIPTION

[0080] like Figure 1 As shown, a method for detecting a shift fork stuck fault in an automatic transmission comprises the following steps:

[0081] 1) A first threshold value and a second threshold value are set to judge the theoretical fault of the automatic transmission fork being stuck. In the present invention, the first threshold value and the second threshold value are both obtained by whole vehicle experimental calibration, that is, the first threshold value and the second threshold value are both empirical values.

[0082] 2) Determine whether the current vehicle driving state is a supporting shift state during the detection cycle, and determine whether there is a theoretical fault of the automatic transmission fork stuck in the following ways:

[0083] 2-1) If the vehicle is in a non-supported shifting state, the automatic transmission is judged to have a theoretical shift fork stuck fault based on the relationship between the "target gear fork position", "shift fork planned gear position", "shift fork control state", "shift fork movement action sub-state" and "number of repeated gear shifts" of the vehicle's automatic transmission and the first threshold value. If the following conditions are met at the same time, the automatic transmission of the vehicle has a theoretical shift fork stuck fault:

[0084] 2-1-1) The target gear shift fork is not in the neutral position;

[0085] 2-1-2) The gear position of the shift fork is the target gear position;

[0086] 2-1-3) The shift fork control state is the gear engaging state;

[0087] 2-1-4) The shift fork movement action sub-state is the secondary gear engagement state;

[0088] 2-1-5) The number of repeated gear shifting times is greater than the first threshold.

[0089] On the contrary, if the relationship between the "target gear fork position", "fork planned gear position", "fork control status", "fork movement action sub-status", and "number of repeated gear shifting times" of the vehicle's automatic transmission and the first threshold value does not meet the above conditions at the same time, then the vehicle's automatic transmission does not have a theoretical fork stuck gear fault.

[0090] 2-2) If the vehicle is in the supporting shifting state, the automatic transmission is judged to have a theoretical shift fork stuck fault according to the relationship between the "target gear fork position", "shift fork planned gear position", "shift fork control state", "shift fork movement action sub-state" and "number of repeated gear shifting times" of the vehicle's automatic transmission and the second threshold value. If the following conditions are met at the same time, the automatic transmission of the vehicle has a theoretical shift fork stuck fault:

[0091] 2-2-1) The target gear shift fork is not in the neutral position;

[0092] 2-2-2) The gear position of the shift fork is the target gear position;

[0093] 2-2-3) The shift fork control state is the gear engaging state;

[0094] 2-2-4) The shift fork movement action sub-state is the secondary gear engagement state;

[0095] 2-2-5) The number of repeated gear shifting is ≥ the second threshold.

[0096] On the contrary, if the relationship between the "target gear fork position", "fork planned gear position", "fork control status", "fork movement action sub-status", and "number of repeated gear shifting times" of the vehicle's automatic transmission and the second threshold value does not meet the above conditions at the same time, then the vehicle's automatic transmission does not have a theoretical fork stuck gear fault.

[0097] It is worth noting that in order to make further judgment on the preliminary theoretical fork stuck fault judgment result, in order to improve the final judgment accuracy. The present invention can also set multiple subsequent parameters, including a third threshold, a reset flag C, a set flag D, and a target gear engagement block counter, etc. Generally speaking, the third threshold is also obtained by calibration of the whole vehicle experiment, that is, the third threshold and the first threshold, the second threshold, and even the detection cycle, their values ​​are all empirical values. These empirical values ​​are obtained by continuous attempts in the whole vehicle experiment to determine the range of the sizes of these empirical values, which can make the present invention the most accurate detection of the automatic transmission fork stuck fault. After the value range of the third threshold is accurately obtained, the third threshold and other subsequent parameters are used to further judge the theoretical fork stuck fault judgment result obtained in the early stage. The specific method is as follows:

[0098] 3-1) When the automatic transmission control unit is powered on, the variable corresponding to the target gear engagement resistance counter reading is initialized to 0, that is, the variable corresponding to the target gear engagement resistance counter reading is assigned a value to avoid logical errors when the software program is running.

[0099] 3-2) Determine the shift fork position corresponding to the current target gear position within the detection cycle, and determine the change state of the current reset mark C by the shift fork position corresponding to the current target gear position, the specific method is as follows:

[0100] 3-2-1) Determine whether the shift fork position corresponding to the current target gear position satisfies the following conditions at the same time:

[0101] ① The shift fork corresponding to the current target gear position is not in the current target gear position during the previous gearbox control unit operation cycle;

[0102] ② The shift fork corresponding to the current target gear position is already in the current target gear position during the current gearbox control unit operation cycle;

[0103] 3-2-2) According to the judgment result of step 3-2-1), the reset flag C is processed in the following manner:

[0104] If the fork position corresponding to the current target gear position satisfies the above conditions at the same time, the value of the reset flag C is set to 1;

[0105] If the shift fork position corresponding to the current target gear does not simultaneously meet the above conditions, the value of the reset flag C is set to 0.

[0106] 3-3) According to the change state of the reset flag C, the reading of the target gear engagement block counter is calculated or processed in the following manner (or, by judging whether the value of the reset flag C changes within the detection period, the reading of the target gear engagement block counter is calculated or processed):

[0107] If the current value of the reset flag C changes from "non-1" to "1", the target gear engagement blocking counter reading is cleared;

[0108] If the current value of the reset flag C does not change from "non-1" to "1", the change state of the setting flag D is determined according to the "fork planned gear position", "fork control state", "fork movement action sub-state" of the automatic transmission during the detection cycle, and the relationship between the "number of repeated gear shifting times" and the first threshold and the second threshold, and according to the change state of the setting flag D, the reading of the target gear shifting block counter is calculated or processed in the following manner (or, by judging whether the value of the setting flag D changes during the detection cycle, the reading of the target gear shifting block counter is calculated or processed):

[0109] ① If the value of the current set flag D changes from "0" to "non-0", the reading of the target gear engagement block counter will increase automatically;

[0110] ② If the value of the current set flag D does not change from "0" to "non-0", the reading of the target gear engagement block counter remains unchanged.

[0111] In the present invention, the specific manner of determining the change state of the setting flag D according to the "shift fork planned gear position", "shift fork control state", "shift fork movement action sub-state" of the automatic transmission during the detection cycle, and the magnitude relationship between the "number of repeated gear shifting times" and the first threshold and the second threshold is as follows:

[0112] 3-3-1) Determine whether the current state of the automatic transmission satisfies the following conditions at the same time, and determine the change state of the setting flag D corresponding to the current transmission control unit operation cycle in the following manner:

[0113] ①The shift fork control state is in gear;

[0114] ② The shift fork moving action sub-state is the secondary gear engaging state;

[0115] ③The gear position of the shift fork is the target gear position;

[0116] 3-3-2) If the current state of the automatic transmission satisfies the above conditions at the same time, the change state of the setting flag D is judged according to the vehicle driving state within the current transmission control unit operation cycle:

[0117] If the vehicle driving state in the current gearbox control unit operation cycle is not a supporting shift state, and the number of repeated gear shifting times is greater than the first threshold, the value of the setting flag D is set to 1;

[0118] If the vehicle driving state in the current gearbox control unit operation cycle is the supporting shift state, and the number of repeated gear shifting is ≥ the second threshold, the value of the setting flag D is set to 1;

[0119] 3-3-3) If the current state of the automatic transmission does not meet the above conditions at the same time, the change state of the setting flag D is determined according to the following conditions:

[0120] ① The gear position corresponding to the previous gearbox control unit operation cycle is not equal to the gear position corresponding to the current gearbox control unit operation cycle;

[0121] ② The gear position corresponding to the current gearbox control unit operation cycle is not neutral;

[0122] ③ The value of the setting flag D in the previous gearbox control unit operation cycle is 1;

[0123] If the current state of the automatic transmission satisfies the above conditions at the same time, the value of the set flag D is set to 0;

[0124] If the current state of the automatic transmission does not meet the above conditions at the same time, the setting flag D remains unchanged.

[0125] 3-4) Repeat steps 3-2) to 3-3) within the detection cycle until the detection cycle ends, and compare the target gear position engagement block counter reading with the third threshold value at this time to determine whether there is a theoretical shift fork stuck fault in the automatic transmission:

[0126] 3-4-1) If the target gear engagement resistance counter reading is ≤ the third threshold, there is no theoretical shift fork jamming fault in the automatic transmission;

[0127] 3-4-2) If the target gear shifting resistance counter reading is greater than the third threshold, there is a theoretical shift fork jamming fault in the automatic transmission.

[0128] In the present invention, a shift fork target gear stuck error counter and a fault detection threshold are also provided. Specifically, the fault detection threshold is obtained by whole vehicle experimental calibration, that is, the fault detection threshold is an empirical value. Each time the automatic transmission is judged to have a shift fork stuck theoretical fault during the detection cycle, the reading of the shift fork target gear stuck error counter is automatically increased until the detection cycle ends, and the reading of the shift fork target gear stuck error counter at this time is compared with the fault detection threshold to judge whether the automatic transmission has a shift fork stuck actual fault:

[0129] If the reading of the shift fork target gear stuck error counter is greater than the fault detection threshold, there is an actual shift fork stuck fault in the automatic transmission, and the shift fork target gear stuck fault code is stored in the memory, and the automatic transmission fault light is lit on the instrument panel;

[0130] If the reading of the shift fork target gear stuck error counter is ≤ the fault detection threshold, there is no actual shift fork stuck fault in the automatic transmission.

[0131] Of course, the above judgment on the fork stuck fault can also be performed simultaneously with the judgment on the fork stuck theoretical fault, and the judgment on the fork stuck fault can be verified with each other, so as to better improve the judgment accuracy of the automatic transmission fork stuck fault of the present invention. Figures 2 to 4 As shown, the software logic code of the above method is stored in the control unit of the automatic transmission (such as TCU, etc.), and the blocking fault of the automatic transmission of the vehicle is judged during the actual driving process of the vehicle:

[0132] After the automatic transmission control unit is powered on, this embodiment collects and processes the vehicle driving state, actual driving gear position and fork gear position related signals, and executes the steps prefixed with SA on the left and SB on the right in parallel, such as Figure 2 For ease of explanation, the steps with the prefix SA on the left are introduced first, followed by the steps with the prefix SB on the right, from left to right.

[0133] The steps on the left are prefixed with SA:

[0134] SA1, if the target gear shift fork is not in the neutral position, enter SA2; otherwise, reset the value of the shift fork target gear stuck error counter, for example, set the value of the shift fork target gear stuck error counter to 0, and continue monitoring.

[0135] SA2, if the gear position of the shift fork is the target gear position, enter SA3; otherwise, reset the value of the shift fork target gear position stuck error counter, for example, set the value of the shift fork target gear position stuck error counter to 0, and continue monitoring.

[0136] SA3, if the shift fork control state is the gear engaging state, enter SA4; otherwise, reset the value of the shift fork target gear stuck error counter, for example, set the value of the shift fork target gear stuck error counter to 0, and continue monitoring.

[0137] SA4, if the shift fork movement action sub-state is the secondary gear engagement state, enter SA5 and SA6; otherwise, reset the value of the shift fork target gear stuck error counter, for example, set the value of the shift fork target gear stuck error counter to 0, and continue monitoring.

[0138] SA5, if the vehicle is in a non-supported gear shifting state, and the number of repeated gear shifting is greater than the set first threshold, then enter S8, and the reading of the shift fork target gear stuck error counter is automatically increased; otherwise, the value of the shift fork target gear stuck error counter is reset, for example, the value of the shift fork target gear stuck error counter is set to 0, and monitoring continues.

[0139] SA6, if the vehicle driving state is supporting gear shifting, and the number of repeated gear shifting is ≥ the second threshold, then enter S8, and the reading of the shift fork target gear stuck error counter is automatically increased; otherwise, the value of the shift fork target gear stuck error counter is reset, for example, the value of the shift fork target gear stuck error counter is set to 0, and monitoring continues.

[0140] The steps on the right with SB as the prefix are as follows:

[0141] SB1, when the automatic transmission control unit is powered on, the target gear engagement block counter is initialized to 0, and then enters SB2.

[0142] SB2: If the value of the reset flag C changes from "non-1" to "1", enter SB3; otherwise, enter SB4.

[0143] SB3, the target gear engagement block counter is set to 0, and then enters SB7.

[0144] SB4, if the value of the set flag D changes from "0" to "non-0", enter SB5; otherwise, enter SB6.

[0145] SB5, the target gear engagement blocking counter is automatically increased, for example, by a step of 1, and then enters SB7.

[0146] SB6, the target gear engagement blocking counter remains unchanged, and then enters SB7.

[0147] SB7, if the target gear engagement block counter is greater than the third threshold, enter S8, and the reading of the fork target gear stuck error counter is automatically increased; otherwise, the value of the fork target gear stuck error counter is reset, for example, the value of the fork target gear stuck error counter is set to 0, and monitoring continues.

[0148] S9, continuously repeat the above detection process until the detection cycle ends, compare the reading of the shift fork target gear stuck error counter at this time with the fault detection threshold, and determine whether there is an actual shift fork stuck fault in the automatic transmission:

[0149] If the reading of the shift fork target gear stuck error counter is greater than the fault detection threshold, the process enters S10, and there is an actual shift fork stuck fault in the automatic transmission, and the shift fork target gear stuck fault code is stored in the memory, and the automatic transmission fault light is turned on on the instrument panel;

[0150] If the reading of the shift fork target gear stuck error counter is ≤ the fault detection threshold, the process goes to S11 and the judgment result is that there is no actual shift fork stuck fault in the automatic transmission.

[0151] Specifically, Figure 3 As shown, the calculation method of the reset flag C in this embodiment is specifically as follows:

[0152] SB201, if the shift fork upper gear position in the previous cycle was a non-target gear position (that is, the shift fork corresponding to the current target gear position was not in the current target gear position in the previous transmission control unit operation cycle), enter SB202; otherwise, enter SB204.

[0153] SB202, if the current cycle of the shift fork upper gear position is the target gear position (that is, the shift fork corresponding to the current target gear position is already in the current target gear position during the current gearbox control unit operation cycle), enter SB203; otherwise, enter SB204.

[0154] SB203, sets the value of the reset flag C to 1, and then ends.

[0155] SB204, sets the value of reset flag C to 0, and then ends.

[0156] Specifically, Figure 4 As shown, the calculation method of the setting flag D in this embodiment is specifically as follows:

[0157] SB401, if the fork control state is in gear, enter SB402; otherwise, enter SB407

[0158] SB402, if the shift fork movement action sub-state is the secondary gear engagement state, enter SB403; otherwise, enter SB407.

[0159] SB403, if the gear position planned for the shift fork is the target gear position, enter SB404 and SB405; otherwise, enter SB407.

[0160] SB404: if the vehicle driving state is to support gear shifting, and the number of repeated gear shifting is ≥ the set second threshold, then enter SB406; otherwise, enter SB407.

[0161] SB405, if the vehicle driving state is non-support shifting, and the number of repeated gear shifting times is greater than the set first threshold, then enter SB406; otherwise, enter SB407.

[0162] SB406, sets the value of the set flag D to 1, and then ends.

[0163] SB407, if the actual driving gear position in the previous cycle ≠ the actual driving gear position in the current cycle (that is, the corresponding gear position in the previous transmission control unit operation cycle is not equal to the corresponding gear position in the current transmission control unit operation cycle), enter SB408; otherwise, enter SB411.

[0164] SB408, if the actual driving gear position in the current cycle is not neutral (that is, the gear position corresponding to the current transmission control unit operation cycle is not neutral), enter SB409; otherwise, enter SB411.

[0165] SB409, if the value of the set flag D in the previous cycle is equal to 1 (that is, the value of the set flag D in the previous transmission control unit operation cycle is 1), enter SB410; otherwise, enter SB411.

[0166] SB410, set flag D to 0, and then end.

[0167] SB411, set flag D remains unchanged, and then ends.

[0168] In summary, the present invention can collect and process relevant signals such as the driving state of the whole vehicle, the actual driving gear and the shift fork gear during the operation of the automatic transmission, and calculate and judge the target gear shift fork position, the planned shift fork gear, the shift fork control state, the shift fork movement action sub-state, the whole vehicle driving state, the actual driving gear, the number of repeated gear shifting times, the reset mark C, the set mark D and the target gear shifting block counter, etc., to accurately detect the shifting process of each target gear in real time (that is, repeatedly judge the shift fork stuck fault by various conditions in a very short time), so that when the shift fork target gear stuck fault occurs, timely processing can be carried out (for example, by taking various solutions such as increasing the gear shifting force, or changing the gear shifting method, optimizing the gear shifting control strategy, etc. to solve the stuck problem), which helps to realize smooth shifting of the shift fork to improve the safety of the driver and passengers, and also facilitates after-sales personnel to quickly lock the cause of the fault during vehicle maintenance, laying a foundation for improving the economy and power of vehicle driving.

[0169] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modification made to the present invention by those skilled in the art without departing from the spirit of the present invention shall fall within the protection scope of the present invention.

Claims

1. A method for detecting a shift fork jamming fault in an automatic transmission, characterized in that: The following steps are involved: 1) Setting a first threshold and a second threshold to determine a theoretical fault of an automatic transmission shift fork being stuck; 2) Determine whether the current vehicle driving state is a supporting shift state during the detection cycle, and determine whether there is a theoretical fault of the automatic transmission fork stuck in the following ways: 2-1) If the vehicle driving state is a non-supported shifting state, it is determined whether the automatic transmission has a theoretical shift fork stuck fault according to the relationship between the "target gear shift fork position", "shift fork planned gear shift position", "shift fork control state", "shift fork movement action sub-state" and "number of repeated gear shifts" of the vehicle's automatic transmission and the first threshold value; 2-2) If the driving state of the whole vehicle is in the supporting shifting state, it is judged whether there is a theoretical shift fork jamming fault in the automatic transmission according to the relationship between the "target gear fork position", "shift fork planned gear position", "shift fork control state", "shift fork movement action sub-state" and "number of repeated gear shifting times" of the automatic transmission of the vehicle and the second threshold.

2. The automatic transmission fork stuck fault detection method according to claim 1, characterized in that: In step 2-1), if the relationship between the "target gear fork position", "fork planned gear position", "fork control state", "fork movement action sub-state", and "number of repeated gear shifting times" of the vehicle's automatic transmission and the first threshold value simultaneously satisfies the following conditions, then the vehicle's automatic transmission has a theoretical fork stuck fault: 2-1-1) The target gear shift fork is not in the neutral position; 2-1-2) The gear position of the shift fork is the target gear position; 2-1-3) The shift fork control state is the gear engaging state; 2-1-4) The shift fork movement action sub-state is the secondary gear engagement state; 2-1-5) The number of repeated gear shifting times is greater than the first threshold.

3. The automatic transmission fork stuck fault detection method according to claim 1, characterized in that: In step 2-2), if the relationship between the "target gear fork position", "fork planned gear position", "fork control state", "fork movement action sub-state", and "number of repeated gear shifting times" of the vehicle's automatic transmission and the second threshold value simultaneously satisfies the following conditions, then the vehicle's automatic transmission has a theoretical fork stuck fault: 2-2-1) The target gear shift fork is not in the neutral position; 2-2-2) The gear position of the shift fork is the target gear position; 2-2-3) The shift fork control state is the gear engaging state; 2-2-4) The shift fork movement action sub-state is the secondary gear engagement state; 2-2-5) The number of repeated gear shifting is ≥ the second threshold.

4. The automatic transmission fork stuck fault detection method according to claim 1, characterized in that: A third threshold, a reset mark C, a set mark D, and a target gear engagement block counter are also provided, and the third threshold, the reset mark C, the set mark D, and the target gear engagement block counter are used to judge the automatic transmission fork stuck theoretical fault during the detection cycle, and the specific method is as follows: 3-1) When the automatic transmission control unit is powered on, the variable corresponding to the target gear engagement block counter reading is initialized; 3-2) determining the shift fork position corresponding to the current target gear position within the detection cycle, and determining the change state of the current reset mark C according to the shift fork position corresponding to the current target gear position; 3-3) According to the change state of the reset flag C, the reading of the target gear engagement block counter is calculated or processed in the following manner: If the current value of the reset flag C changes from "non-1" to "1", the target gear engagement block counter reading is cleared; If the current value of the reset flag C does not change from "non-1" to "1", the change state of the set flag D is determined according to the "fork planned gear position", "fork control state", "fork movement action sub-state" of the automatic transmission during the detection cycle, and the relationship between the "number of repeated gear shifting times" and the first threshold and the second threshold, and the reading of the target gear position gear shifting block counter is calculated or processed in the following manner according to the change state of the set flag D: ① If the value of the current set flag D changes from "0" to "non-0", the reading of the target gear engagement block counter will increase automatically; ② If the value of the current set flag D does not change from "0" to "non-0", the reading of the target gear engagement block counter remains unchanged; 3-4) Repeat steps 3-2) to 3-3) within the detection cycle until the detection cycle ends, and compare the target gear position engagement block counter reading with the third threshold value at this time to determine whether there is a theoretical shift fork stuck fault in the automatic transmission: 3-4-1) If the target gear engagement resistance counter reading is ≤ the third threshold, there is no theoretical shift fork jamming fault in the automatic transmission; 3-4-2) If the target gear shifting resistance counter reading is greater than the third threshold, there is a theoretical shift fork jamming fault in the automatic transmission.

5. The automatic transmission fork stuck fault detection method according to claim 4, characterized in that: In step 3-2), the specific method of determining the change state of the current reset mark C by the shift fork position corresponding to the current target gear position is as follows: 3-2-1) Determine whether the shift fork position corresponding to the current target gear position satisfies the following conditions at the same time: ① The shift fork corresponding to the current target gear position is not in the current target gear position during the previous gearbox control unit operation cycle; ② The shift fork corresponding to the current target gear position is already in the current target gear position during the current gearbox control unit operation cycle; 3-2-2) According to the judgment result of step 3-2-1), the reset flag C is processed in the following manner: If the shift fork position corresponding to the current target gear position satisfies the above conditions at the same time, the reset flag C is set to 1; If the shift fork position corresponding to the current target gear does not simultaneously meet the above conditions, the reset flag C is set to 0.

6. The automatic transmission fork stuck fault detection method according to claim 4, characterized in that: In step 3-3), the specific method of determining the change state of the setting flag D according to the relationship between the "shift fork planned gear position", "shift fork control state", "shift fork movement action sub-state" and "number of repeated gear shifting times" of the automatic transmission and the first threshold and the second threshold within the detection cycle is as follows: 3-3-1) Determine whether the current state of the automatic transmission satisfies the following conditions at the same time, and determine the change state of the setting flag D of the current transmission control unit operation cycle in the following manner: ①The shift fork control state is in gear; ② The shift fork moving action sub-state is the secondary gear engaging state; ③The gear position of the shift fork is the target gear position; 3-3-2) If the current state of the automatic transmission satisfies the above conditions at the same time, the change state of the setting flag D is judged according to the vehicle driving state within the current transmission control unit operation cycle: If the vehicle driving state in the current gearbox control unit operation cycle is not a supporting shift state, and the number of repeated gear shifting times is greater than the first threshold, the setting flag D is set to 1; If the vehicle driving state in the current gearbox control unit operation cycle is the supporting shift state, and the number of repeated gear shifting is ≥ the second threshold, the setting flag D is set to 1; 3-3-3) If the current state of the automatic transmission does not meet the above conditions at the same time, the change state of the setting flag D is determined according to the following conditions: ① The gear position corresponding to the previous gearbox control unit operation cycle is not equal to the gear position corresponding to the current gearbox control unit operation cycle; ② The gear position corresponding to the current gearbox control unit operation cycle is not neutral; ③ The value of the setting flag D in the previous gearbox control unit operation cycle is 1; If the current state of the automatic transmission meets the above conditions at the same time, the set flag D is set to 0; If the current state of the automatic transmission does not meet the above conditions at the same time, the setting flag D remains unchanged.

7. The automatic transmission fork stuck fault detection method according to claim 1, characterized in that: A shift fork target gear position stuck error counter and a fault detection threshold are also provided. Each time a shift fork stuck theoretical fault is determined to exist in the automatic transmission during the detection cycle, the shift fork target gear position stuck error counter is incremented until the detection cycle ends. The reading of the shift fork target gear position stuck error counter at this time is compared with the fault detection threshold to determine whether the automatic transmission has a shift fork stuck actual fault: If the reading of the shift fork target gear stuck error counter is greater than the fault detection threshold, the automatic transmission has a shift fork stuck actual fault; If the reading of the shift fork target gear stuck error counter is ≤ the fault detection threshold, there is no actual shift fork stuck fault in the automatic transmission.

8. The automatic transmission fork stuck fault detection method according to claim 7, characterized in that: The fault detection threshold is obtained by whole vehicle test calibration.

9. The automatic transmission fork stuck fault detection method according to claim 1, characterized in that: The first threshold and the second threshold are both obtained through whole vehicle experiment calibration.

10. The automatic transmission fork stuck fault detection method according to claim 4, characterized in that: The third threshold is obtained by whole vehicle test calibration.

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