A test method for the performance of a vehicle transmission synchronizer and a vehicle

Abstract

The embodiment of the present application discloses a method for testing the performance of a vehicle transmission synchronizer and a vehicle. The testing method includes the following steps: controlling the vehicle to make the actual vehicle speed greater than the preset vehicle speed; confirming the actual gear, the target gear and the synchronizer corresponding to the target gear; operating the synchronizer to perform a gear shifting operation to judge the performance of the synchronizer. The testing method in the embodiment of the present application can realize the change of the maximum synchronous speed difference, provide the maximum synchronous speed difference that can be designed and adopted for the development and control of the gear shifting system, and at the same time can also use the change of the maximum synchronous speed difference to evaluate the adhesion performance of the carbon strip of the synchronizer synchronizing ring.

Description

Technical Field

[0001] This application relates to the technical field of vehicle performance testing, and particularly to a method for testing the performance of a vehicle transmission synchronizer and a vehicle. Background Art

[0002] With the further development of the automotive industry, market competition has become increasingly fierce. The market has stricter requirements for product performance, and product types have also become more diverse. Therefore, when developing new products, it is necessary to better meet customer needs. The function of a vehicle transmission synchronizer is to complete gear shifting under the condition of ensuring rotational speed synchronization, which can avoid gear clash and shifting shock during gear shifting. The synchronizer mainly consists of a sliding sleeve, a synchronizer ring, etc.

[0003] Related technologies generally use bench tests to test the performance of synchronizers, but it is necessary to develop a dedicated synchronizer test bench, and the bench scheme is very complex. Summary of the Invention

[0004] In view of this, embodiments of this application are expected to provide a method for testing the performance of a vehicle transmission synchronizer and a vehicle, which can verify the performance of the synchronizer by evaluating the design boundary parameters of the maximum synchronization rotational speed during gear shifting of the synchronizer.

[0005] To achieve the above object, on the one hand, an embodiment of this application provides a method for testing the performance of a vehicle transmission synchronizer, including:

[0006] Controlling the vehicle so that the actual vehicle speed is greater than the preset vehicle speed;

[0007] Confirming the actual gear position, the target gear position, and the synchronizer corresponding to the target gear position;

[0008] Operating the synchronizer to perform a gear shifting operation to judge the performance of the synchronizer.

[0009] In some embodiments, the vehicle is controlled to start in a first test field, and the synchronizer is operated to perform a gear shifting operation in a second test field, where the second test field is connected to the first test field. Among them, the adhesion coefficient of the first test field is greater than the adhesion coefficient of the second test field.

[0010] In some embodiments, the first test field is a flat snow-covered road surface or a flat road surface with an adhesion coefficient greater than or equal to 0.2, and the second test field is a flat ice-covered road surface or a flat road surface with an adhesion coefficient less than or equal to 0.15.

[0011] In some embodiments, if when the actual vehicle speed of the vehicle is greater than the preset vehicle speed and the vehicle has not reached the second test field, the vehicle slides to the second test field, and in the second test field, the actual vehicle speed of the vehicle is greater than or equal to the preset vehicle speed.

[0012] In some embodiments, the step of operating the synchronizer to perform a gear shift operation specifically includes:

[0013] applying a braking action on the vehicle so that the input shaft speed of the gearbox in the actual gear position is equal to a first preset speed;

[0014] Depress the brake to the bottom or control the clutch to disengage, and operate the synchronizer to shift to the neutral position;

[0015] When the speed of the input shaft of the gearbox at the target gear position is equal to a second preset speed, the synchronizer is controlled to shift to the target gear position.

[0016] In some embodiments, before the step of controlling the vehicle so that the actual vehicle speed is greater than the preset vehicle speed, the testing method includes:

[0017] The vehicle is started after being adjusted to a preset state.

[0018] In some embodiments, the preset state of the vehicle includes: disabling ESC / ABS functions and TCU diagnosis of ABS related functions.

[0019] In some embodiments, the testing method comprises:

[0020] Acquiring the actual speed of the vehicle, the gear position signal of the transmission, the engine speed, the speed of the transmission input shaft, and the position signal of the shift control mechanism;

[0021] The gear vehicle speed corresponding to the maximum synchronous speed difference between the synchronizing end and the synchronized end of the synchronizer corresponding to the target gear is analyzed.

[0022] In some embodiments, under the condition that the maximum synchronous speed difference of the synchronizer is a first preset value, the number of gear shift operations is greater than or equal to 2.

[0023] Another aspect of the present application provides a vehicle for testing the performance of a transmission synchronizer, the vehicle comprising:

[0024] engine;

[0025] a gearbox, comprising a clutch and a synchronizer for shifting gears, the gearbox being drivingly connected to the engine via the clutch;

[0026] a gearbox control unit, configured to obtain the input shaft speed, actual gear position, target gear position, and observed torque of the clutch of the gearbox;

[0027] The vehicle-mounted controller is used to receive the signal obtained by the transmission control unit, calculate the synchronizing end speed, the synchronized end speed and the shift residual torque of the synchronizer, and perform the synchronizer motion state analysis.

[0028] The test method for the performance of the vehicle transmission synchronizer provided by the embodiments of the present application can perform braking and shifting operations by controlling the vehicle at a sufficiently high speed, and set a gear change that can cause the maximum synchronous speed difference to change under the synchronous action of the synchronizer, that is, switch from the actual gear to the target gear, and then judge the performance of the synchronizer by observing the operating state of the synchronizer when the vehicle shifts gears. In this way, the maximum synchronous speed difference change can be achieved, providing the maximum synchronous speed difference that can be designed and adopted for the development and control of the shifting system, and at the same time, the adhesion performance of the carbon strip of the synchronizing ring of the synchronizer can also be evaluated by using the change of the maximum synchronous speed difference. Description of the Drawings

[0029] Figure 1 It is a schematic structural diagram of a dual-clutch transmission provided by the embodiments of the present application;

[0030] Figure 2 It is a schematic structural diagram of the power transmission route of the D1 gear of a dual-clutch transmission provided by the embodiments of the present application;

[0031] Figure 3 It is a schematic structural diagram of the power transmission route of the R gear of a dual-clutch transmission provided by the embodiments of the present application;

[0032] Figure 4 It is a schematic structural diagram of a lock-ring synchronizer provided by the embodiments of the present application;

[0033] Figure 5 It is a schematic flow diagram of a test method for the performance of a vehicle transmission synchronizer provided by the embodiments of the present application;

[0034] Figure 6 It is a schematic diagram of a test site provided by the embodiments of the present application;

[0035] Figure 7 It is a schematic diagram of the shifting synchronization process between single input shafts provided by the embodiments of the present application;

[0036] Figure 8 It is a schematic diagram of the shifting synchronization process between inner and outer input shafts provided by the embodiments of the present application;

[0037] Figure 9 It is a specific schematic flow diagram of a test method for the performance of a vehicle transmission synchronizer provided by the embodiments of the present application.

[0038] Description of the Reference Numerals

[0039] Dual clutch transmission 10; external input shaft 101; internal input shaft 102; gear 103; gear selector 104; first clutch 105; second clutch 106; synchronizer 20; hub 201; slider 202; sleeve 203; synchronizing ring 204; engaging teeth 205; locking pin 206. Detailed implementation

[0040] It should be noted that, without conflict, the embodiments and technical features in the embodiments of the present application can be combined with each other. The detailed description in the specific implementation should be understood as an explanatory illustration of the purpose of the present application and should not be regarded as an improper limitation of the present application.

[0041] Common types of transmissions include: manual transmission, automatic transmission, semi-automatic transmission, dual clutch transmission (Dual Clutch Transmission, abbreviated as DCT), and continuously variable transmission. Among them, DCT can achieve fast shifting and also has high transmission efficiency. However, it is prone to obvious jerks during the shifting process and has difficulty in heat dissipation. Therefore, it is necessary to improve the manufacturing and processing precision.

[0042] Refer to Figure 1 , taking a dual clutch transmission 10 (hereinafter referred to as DCT) of a certain structure as an example, the numbers 1-6, R in the round sleeve represent gears. The two clutches operate independently. The first clutch 105 controls the even gears, that is, the second gear, the fourth gear, and the sixth gear. The second clutch 106 controls the odd gears, that is, the first gear, the third gear, the fifth gear, and the reverse gear. In the center of the DCT is a power input shaft composed of two parts. The odd and even gears are separated by using a dual variable-speed input shaft structure. Among them, the external input shaft 101 is a hollow shaft for providing power for the second gear and the fourth gear; the internal input shaft 102 is nested in the external input shaft 101 for providing power for the first gear, the third gear, and the fifth gear.

[0043] During the shifting process of the DCT, first, it is necessary to control the clutch to brake, disconnect the engine from the transmission, and interrupt the power transmitted to the transmission. Then, operate the shift lever to achieve gear shifting. In this process, it involves the switching and engagement of the gear selector 104 and different gears 103. The synchronizer 20 can use friction to eliminate the rotational speed difference between the gears, make the gears match before engagement, so as to achieve the synchronization between the synchronized end and the synchronizing end to prevent tooth grinding.

[0044] Refer to Figure 2 and Figure 3 , taking a DCT of a certain structure as an example, Figure 2 is a schematic diagram of the power transmission route for the D1 gear, Figure 3Schematic diagram of the power transmission route for reverse gear. Taking the shift from D1 to R as an example, during the driving in D1 gear, power is input from the external input shaft IS1, coupled through the 5th gear and the synchronizer SC, and transmitted through the gear on the internal input shaft IS2 and the 2nd gear to the first output shaft OS1, and then the power is output from the first output shaft OS1; during the gearshift from D1 to R, the synchronizer S1 switches from being coupled with the 2nd gear to the neutral position, and the synchronizer S2 synchronizes from the neutral position to being coupled with the R gear. At this time, the power transmission route is the external input shaft IS1, 5th gear, synchronizer SC, 6th gear, gear on the internal input shaft IS2, 2nd gear, R gear, and the second output shaft OS2. Since there is an additional R gear in the middle, the transmission direction is opposite to the previous one, and the first output shaft OS1 and the second output shaft OS2 are coupled to the differential output end with the same steering direction.

[0045] The existing common types of synchronizers are: constant pressure type, inertial type, and self-boosting type. Among them, the inertial type includes lock-ring type and lock-pin type. In the existing car market, most cars use lock-ring type synchronizers. Refer to Figure 4 , the lock-ring type synchronizer 20 includes a toothed hub 201, a slider 202, engaging teeth 203, a synchronizing ring 204, a gear sleeve 205, a lock pin 206, and a carbon strip layer 207. During the gearshift, the synchronizing ring 204 rubs against the friction cone surface where the engaging teeth 203 are located, and the friction is used to transmit force to synchronize the rotational speeds at both ends of the engaging teeth.

[0046] It should be noted that during the change process of the synchronous speed difference under the synchronous action of the synchronizer speed, the synchronous performance of the synchronizer can reflect the adhesion performance of the carbon strip of the synchronizing ring. Specifically, the greater the synchronous speed difference under the synchronous action of the synchronizer speed, the greater the frictional torque and sliding friction work generated by the synchronizer, which will cause the working environment temperature of the synchronizing ring to rise and the stress on it to increase. When the working environment temperature of the synchronizing ring is too high, the carbon-coated friction layer material on the surface of the synchronizing ring will be damaged, resulting in the loss of the friction synchronization function of the synchronizer. Therefore, in the dynamic test of the synchronizer at different speed differences, the synchronous performance of the synchronizer is affected by the adhesion performance of the carbon strip of the synchronizing ring, and the adhesion performance of the carbon strip of the synchronizing ring can be evaluated according to the degree of damage of the carbon strip.

[0047] In view of this, the embodiments of the present application all take DCT models using the lock-ring type synchronizer 20 as examples. Refer to Figure 5 , on the one hand, the embodiments of the present application provide a test method for the performance of a vehicle transmission synchronizer. The test method includes the following steps:

[0048] S1: Control the vehicle so that the actual vehicle speed is greater than the preset vehicle speed;

[0049] S2: Confirm the actual gear, target gear, and the synchronizer corresponding to the target gear;

[0050] S3: Operate the synchronizer to perform a gear shift operation to determine the performance of the synchronizer.

[0051] The test method provided by the embodiments of the present application enables the vehicle to have a high enough speed by giving the vehicle a sufficient vehicle speed to perform braking and gear shift operations, and sets a gear change that can cause the maximum synchronous speed difference of the synchronizer to change under the synchronous action, that is, switching from the actual gear to the target gear. Then, by observing the operating state of the synchronizer and the change rate of the input shaft speed when the vehicle shifts gears, the performance of the synchronizer can be determined. In this way, the maximum synchronous speed difference change can be achieved, providing the maximum synchronous speed difference that can be designed and adopted for the development and control of the gear shift system. At the same time, the adhesion performance of the synchronizer carbon strip can also be evaluated using the change in the maximum synchronous speed difference.

[0052] The following details the specific implementation manners of each step.

[0053] S1: Control the vehicle so that the actual vehicle speed is greater than the preset vehicle speed.

[0054] It can be understood that making the actual vehicle speed greater than the preset vehicle speed is to enable the vehicle to have a high enough speed to perform braking and gear shift operations.

[0055] The preset vehicle speed is determined according to the transmission configuration conditions, the conversion relationship between the vehicle speed and the transmission ratio of the synchronizer being tested at different gears, and the maximum synchronous speed difference of the synchronizer during the gear shift process. For example, in the case of switching from the Drive (abbreviated as D) gear to the Reverse (abbreviated as R) gear, the theoretical estimation method of the preset vehicle speed is that, ignoring the gear shift time, it is considered that the vehicle speed is the same before and after the gear shift, and this vehicle speed is set as V. Then, the rotational speed n1 of the input shaft of the transmission before the gear shift = V / I d , I d is the D - gear transmission ratio, and the rotational speed n2 of the input shaft of the transmission after the gear shift = V / I r , I r is the R - gear transmission ratio, and the synchronous speed difference of the synchronizer is the vector difference of the rotational speeds of the input shaft before and after the gear shift. At the same time, there is a linear correspondence between the synchronous speed difference of the synchronizer and the vehicle speed. The preset maximum vehicle speed, that is, the preset vehicle speed, can be inversely calculated through the maximum synchronous speed difference designed by the synchronizer.

[0056] S2: Confirm the actual gear, the target gear, and the synchronizer corresponding to the target gear.

[0057] The actual gear refers to the current gear corresponding to when the vehicle is controlled to accelerate until the actual vehicle speed is greater than the preset vehicle speed; by switching the actual gear to the corresponding gear, the maximum synchronous speed difference change under the synchronous action of the synchronizer rotational speed can be achieved, and this corresponding gear is the target gear.

[0058] The actual gear and the target gear are set according to the shifting function of the transmission. Depending on different driving conditions, the same actual gear corresponds to different target gears. For example, in one driving condition when the vehicle shifts from a lower gear to a higher gear, such as when shifting out of the Park (P) gear and into the D1 gear, the D1 gear is the actual gear, and the D2 gear is the target gear. In another driving condition when the vehicle shifts from a higher gear to a lower gear, such as when shifting from a higher gear to the D1 gear, the D1 gear is the actual gear, and the R gear is the target gear.

[0059] S3: Operate the synchronizer to perform a shifting operation to judge the performance of the synchronizer.

[0060] Specifically, by controlling the vehicle to switch from the actual gear to the target gear to complete the shifting operation, thereby achieving a change in the maximum synchronous speed difference under the synchronous action of the synchronizer, and judging the performance of the synchronizer by testing whether the driver observes that the gear is engaged and whether the change rate of the input shaft speed is abnormal. If the synchronizer completes the gear engagement and the change rate of the input shaft speed is normal, the performance of the synchronizer is good; if the synchronizer does not complete the gear engagement and the change rate of the input shaft speed is abnormal, the performance of the synchronizer needs to be improved or the shifting system development and control are adjusted to provide the maximum synchronous speed design boundary parameters.

[0061] In some embodiments, step S3 of operating the synchronizer to perform a shifting operation specifically includes:

[0062] S31: Tap the brakes to make the input shaft speed of the transmission in the actual gear equal to the first preset speed.

[0063] It can be understood that tapping the brakes is to ensure that the vehicle travels in a straight line without losing stability. At the same time, braking can achieve clutch separation and reduce the influence of bearing the driving end transmission torque during the synchronous condition.

[0064] The first preset speed refers to the initial speed during the shifting process of the input shaft of the transmission. Reducing the input shaft speed of the transmission in the actual gear to the first preset speed is to control the initial synchronous speed during the test to ensure that the maximum synchronous speed difference can be achieved during the test.

[0065] S32: Press the brake pedal to the bottom or control the clutch to disengage, and operate the synchronizer to shift to the neutral position.

[0066] It can be understood that the synchronizer transmits torque by the engagement of the gear hub 201 and the engagement teeth 203 of the gear. Its unengaged state is called the neutral position of the synchronizer. Pressing the brake pedal to the bottom or controlling the clutch to disengage and operating the synchronizer to shift to the neutral position can decouple the input shaft corresponding to the target gear from the power train, thereby reducing the load during synchronizer shifting and reducing the synchronous torque for unlocking and shifting the ring during the synchronous inertia synchronization process.

[0067] S33: When the rotational speed of the input shaft of the gearbox at the target gear position is equal to the second preset rotational speed, control the synchronizer to shift to the target gear position.

[0068] The synchronizer shifting to the target gear position corresponds to the vehicle switching from the actual gear to the target gear. The second preset rotational speed is obtained from the first preset rotational speed through a certain proportional relationship. When the vehicle switches from the actual gear to the target gear and the rotational speed of the input shaft changes from the first preset rotational speed to the second preset rotational speed, by controlling the final synchronization rotational speed during the test process, the change of the maximum synchronization rotational speed difference can be achieved under the synchronization effect of the synchronizer.

[0069] It should be noted that the first preset rotational speed and the second preset rotational speed can be obtained through comprehensive calculation based on the designed synchronization rotational speed difference in the test, the gearbox configuration, and the speed ratio conditions from the synchronizer to the wheel end. In the bench steady-state test involving the synchronizer, the specific rotational speed calculation, vehicle speed calculation, etc. have been widely and maturely applied in related technologies and will not be elaborated here.

[0070] Specifically, apply spot braking to the vehicle to make the rotational speed of the input shaft of the gearbox at the target gear position equal to the second preset rotational speed, then step on the brake to the bottom or control the clutch to disengage, and control the synchronizer to shift to the target gear position. During the process of controlling the synchronizer to shift to the target gear position, it is necessary to test whether the driver notices situations such as gear shifting failure error reporting and abnormal rotational speed change rate of the vehicle. If the above situations occur, it indicates that the synchronizer function is abnormal and the test is unsuccessful; if the above situations occur and gear shifting can be completed, it indicates that the synchronizer function is normal and a test process is successfully completed.

[0071] In some embodiments, refer to Figure 7 , when the shifting operation is between the gears of a single input shaft of the gearbox, the actual gear to target gear shift is a shift between the gears of a single input shaft, that is, a shift between odd gears or a shift between even gears. For example, when shifting from the actual gear D3 to the target gear D1, both gears are located on the inner input shaft of the gearbox. Therefore, the rotational speed changes during the shift between the two gears occur on the inner input shaft. During the shifting process, make the rotational speed of the inner input shaft of gear D3 equal to the first preset rotational speed, then operate the synchronizer to shift to the intermediate position, and then control the vehicle to brake and decelerate to make the rotational speed of the inner input shaft of gear D1 equal to the second preset rotational speed, and control the synchronizer to shift to the target gear position. During this process, the rotational speed of the inner input shaft of the gearbox drops from the first preset rotational speed to the second preset rotational speed, achieving the change of the maximum rotational speed difference.

[0072] In some embodiments, refer to Figure 8, when the shift operation is performed between the gears of the internal and external input shafts of the transmission, the actual gear is switched to the target gear, which is a shift between the internal and external input shafts, that is, a mutual switch between odd gears and even gears. For example, when switching from the actual gear D1 to the target gear R, the D1 gear is located on the external input shaft of the transmission, and the R gear is located on the internal input shaft of the transmission. Therefore, the rotational speed changes during the two-gear shift act on the internal input shaft and the external input shaft respectively. During the shift process, the rotational speed of the external input shaft of the D1 gear is made equal to the first preset rotational speed, then the synchronizer is operated to the intermediate position, and then the vehicle is braked and decelerated to make the rotational speed of the internal input shaft of the R gear equal to the second preset rotational speed, and the synchronizer is controlled to the target gear position. During this process, the internal and external input shafts of the transmission act on each other alternately, and the rotational speed drops from the first preset rotational speed of the internal input shaft to the second preset rotational speed of the external input shaft, achieving the change of the maximum rotational speed difference.

[0073] See Figure 6 , the performance test of the vehicle transmission synchronizer in the embodiments of the present application is carried out in a test site. The test site includes a first test site and a second test site. For example, both ends of the second test site are respectively connected to the first test site, where the adhesion coefficient of the first test site is greater than that of the second test site.

[0074] In some embodiments, the method for testing the performance of the vehicle transmission synchronizer is specifically to control the vehicle to start in the first test site and operate the synchronizer to perform a shift operation in the second test site. That is, control the vehicle to start in the first test site and control the vehicle to make the actual vehicle speed greater than the preset vehicle speed. Before entering the second test site from the first test site, it is necessary to confirm the actual gear, the target gear, and the synchronizer corresponding to the target gear. Finally, enter the second test site from the first test site and operate the synchronizer to perform a shift operation in the second test site.

[0075] It should be noted that making the actual vehicle speed greater than the preset vehicle speed is to ensure that the vehicle has a high enough vehicle speed before entering the second test site, and then during the process of operating the synchronizer to perform a shift operation in the second test site, the braking and shift operations can be completed.

[0076] It should be noted that the higher the road surface adhesion coefficient, the greater the driving force or braking force that the vehicle can utilize. When the vehicle needs to complete the starting and accelerating operation in the first test site, the requirement for the road surface adhesion coefficient is relatively low. However, when the vehicle operates the synchronizer for gear shifting in the second test site, it is necessary to eliminate the influence of other factors and create an extreme situation to obtain the design limit of the synchronizer performance under the designed extreme conditions, and the requirement for the road surface adhesion coefficient is relatively high. Therefore, the adhesion coefficient of the first test site is greater than that of the second test site. The adhesion coefficient of the first test site needs to meet the normal operation of the vehicle; the adhesion coefficient of the second test site needs to eliminate the torque transmitted by the transmission drive shaft system as much as possible and minimize the load of the drive train. In this way, the torque transmitted during gear shifting of the synchronizer can be reduced.

[0077] Specifically, in some embodiments, the first test site is a flat snow road surface or a flat road surface with an adhesion coefficient greater than or equal to 0.2, and the second test site is a flat ice road surface or a flat road surface with an adhesion coefficient less than or equal to 0.15.

[0078] In some embodiments, if the actual speed of the vehicle is greater than the preset speed and the vehicle has not reached the second test site, the vehicle slides to the second test site, and the actual speed of the vehicle in the second test site is greater than or equal to the preset speed.

[0079] Specifically, after controlling the vehicle to make the actual speed greater than the preset speed in the first test site, there will be three situations. One is that the vehicle just reaches the second test site, then the vehicle enters the second test site with the actual speed greater than the preset speed; the second is that the vehicle has not reached the second test site, and the vehicle is controlled to slide to the second test site. At this time, the actual speed of the vehicle is greater than or equal to the preset speed; the third is that the vehicle has not reached the second test site, and the vehicle is controlled to slide. During the sliding process, the actual speed of the vehicle is less than the preset speed, then it is necessary to re-control the vehicle to make the actual speed greater than the preset speed and make the vehicle enter the second test site with the actual speed greater than the preset speed.

[0080] It should be noted that there is a human-machine interaction module on the display device of the vehicle, which can display the value of the vehicle speed signal. The test driver can judge whether the actual speed of the vehicle is greater than or equal to the preset speed by visually observing the value of the vehicle speed signal; during the test, the test driver can judge whether the vehicle reaches the second test site from the first test site by visually observing the actual situation on the spot.

[0081] In some embodiments, before the step of controlling the vehicle to make the actual speed greater than the preset speed, the test method includes: adjusting the vehicle to the preset state and then starting the vehicle.

[0082] It can be understood that in order to cope with the situation that the adhesion coefficient of the second test site is relatively low, which may cause the vehicle to skid, it is necessary to adjust the relevant equipment that affects the vehicle's acceleration, shifting, and the torque at both ends of the synchronizer. In this way, the vehicle is adjusted to a preset state to ensure the normal driving of the vehicle within the second test site.

[0083] Specifically, in some embodiments, the preset state of the vehicle includes: turning off the functions of the Electronic Stability Controller (ESC) or the Antilock Brake System (ABS) and the diagnosis of the ABS-related functions by the Telematics Control Unit (TCU). When driving on a site with a low adhesion coefficient and encountering a skidding condition, the ESC will send a torque limit request to the TCU, which affects the acceleration and shifting functions; the braking torque distribution will also generate a resistance torque, which affects the torque at both ends of the synchronizer. In this way, the smooth operation of the vehicle can be achieved; after turning off the ABS diagnosis, the ABS cannot send the vehicle speed and wheel speed signals to the TCU, which can ensure the normal operation of the vehicle. If the TCU does not turn off the ABS diagnosis, it will follow the gearbox limp-home strategy, the clutch will open, and the vehicle cannot accelerate.

[0084] In some embodiments, the test method includes obtaining the actual vehicle speed, the gear signal of the gearbox, the engine speed, the input shaft speed of the gearbox, and the position signal of the shift control mechanism; and analyzing the gearbox speed corresponding to the maximum synchronous speed difference between the synchronous end and the desynchronized end of the synchronizer for the target gear.

[0085] It can be understood that the gearbox speed refers to the vehicle speed designed for the test in the test method, which is used to evaluate the vehicle speed corresponding to the maximum synchronous speed difference of the synchronizer or the vehicle speed continuously adjusted and verified when verifying the maximum synchronous speed difference, that is, the preset vehicle speed, the vehicle speed corresponding to the first preset speed, and the vehicle speed corresponding to the second preset speed. During the actual test, the vehicle's acceleration, observing the vehicle speed, the target shaft speed, and the shifting operation are all carried out around the gearbox speed. In addition, the first preset speed is the product of the vehicle speed and the speed ratio corresponding to the starting gear of the synchronizer, the second preset speed is the product of the vehicle speed and the speed ratio corresponding to the target gear of the synchronizer, the synchronous speed difference is the difference between the first preset speed and the second preset speed, and the synchronous speed difference of the synchronizer is related to the designed shifting vehicle speed.

[0086] In the experimental design of the described test method, the actual vehicle speed, the gear signal of the transmission, the engine speed, and the transmission input shaft speed are the information required to calculate the maximum synchronous speed difference at both ends of the synchronizer. The above information is obtained for analyzing the gear vehicle speed corresponding to the maximum synchronous speed difference between the synchronous end and the non-synchronous end of the synchronizer corresponding to the target gear. Then, based on the calculated maximum synchronous speed difference that the synchronizer can withstand, the synchronization performance of the synchronizer is evaluated, and at the same time, the maximum synchronous speed difference that can be designed and adopted for the development and control of the shift system is obtained.

[0087] It should be noted that during the actual test, since the ESC / ABS is turned off, the Global Positioning System (GPS) is referenced as the vehicle speed for shifting, and the gear signal of the transmission, the engine speed, the transmission input shaft speed, and the shift control mechanism position signal are referenced as the information for observing the start and end of shifting. The engine speed signal is mainly used to determine whether the engine speed exceeds the engine over-speed fuel cut-off speed during shifting. Shifting at speeds exceeding this speed has no practical significance.

[0088] In some embodiments, when the maximum synchronous speed difference of the synchronizer is at the first preset value, the number of shift operations is greater than or equal to 2.

[0089] Specifically, after successfully completing one test process, it is necessary to repeat at least one test process again. When the maximum synchronous speed difference of the synchronizer is at the first preset value, the shift operation is completed. In this way, the test error can be reduced, other factors can be excluded, and the accuracy of the test results can be ensured.

[0090] In some embodiments, referring to Figure 9 , the specific process of the test method for the performance of the vehicle transmission synchronizer is as follows:

[0091] [[ID=I7]]P1: The vehicle enters the first test site. After adjusting the vehicle to the preset state, start the vehicle to ensure that the vehicle can drive normally under the skidding condition.

[0092] P2: Control the vehicle so that the actual vehicle speed is greater than the preset vehicle speed to ensure that the vehicle has a high enough speed for braking and shifting operations.

[0093] P3: Confirm the actual gear, the target gear, and the synchronizer corresponding to the target gear to ensure that the synchronous speed function of the synchronizer can be realized to achieve the change of the maximum synchronous speed difference.

[0094] P4: After completing the above operations, determine whether the vehicle enters the second test site. If the vehicle does not enter the second test site, perform step P5; if the vehicle enters the second test site, perform step P7.

[0095] P5: Control the vehicle to glide. During the glide, the vehicle will gradually slow down and continue to approach the second test site.

[0096] P6: Determine whether the actual vehicle speed is less than the preset speed. If the actual vehicle speed is less than the preset speed, execute step P2; if the actual vehicle speed is not less than the preset speed, execute step P4.

[0097] P7: Apply the brakes to the vehicle so that the input shaft speed of the gearbox in the actual gear is equal to the first preset speed. The initial synchronous speed during the test is controlled to ensure that the maximum synchronous speed difference can be achieved during the test.

[0098] P8: Press the brake to the bottom or control the clutch to disengage, and operate the synchronizer to shift to the neutral position to decouple the input shaft corresponding to the target gear from the transmission system, thereby reducing the load on the synchronizer during gear shifting and reducing the synchronous inertia. The synchronizing torque of the unlocking and shifting ring during synchronization is reduced.

[0099] P9: Apply the brakes to the vehicle to make the input shaft speed of the gearbox in the actual gear equal to the second preset speed. The final synchronous speed during the test is controlled to achieve a change in the maximum synchronous speed difference.

[0100] P10: Press the brake to the bottom or control the clutch to disengage, operate the synchronizer to shift to the target gear position, and realize the shift operation under the change of the maximum synchronous speed difference.

[0101] P11: Determine whether the synchronizer has completed the gear shift and whether the speed change rate is abnormal during the gear shift process.

[0102] P12: Obtains the actual vehicle speed, gear position signal of the transmission, engine speed, transmission input shaft speed and shift control mechanism position signal, and then receives the signal obtained by the transmission control unit through the vehicle controller.

[0103] P13: Analyze the gear vehicle speed corresponding to the maximum synchronous speed difference between the synchronizing end and the synchronized end of the synchronizer corresponding to the target gear, calculate the synchronizer synchronizing end speed, synchronized end speed and gear shift residual torque.

[0104] P14: The maximum synchronous speed difference that the synchronizer can withstand is obtained based on the calculation to evaluate the synchronization performance of the synchronizer, and at the same time, the maximum synchronous speed difference that can be designed and adopted for the development and control of the gear shifting system is obtained.

[0105] P15: The adhesion performance of the synchronizer ring carbon strip is evaluated by observing the damage degree of the synchronizer ring carbon strip under the change of the maximum synchronous speed difference. That is, the smaller the damage degree of the synchronizer ring carbon strip under the change of the maximum synchronous speed difference, the better the adhesion performance of the synchronizer ring carbon strip.

[0106] On the other hand, an embodiment of the present application provides a vehicle for testing the performance of a transmission synchronizer. The vehicle includes an engine, a transmission, a Transmission Control Unit (TCU), and an on-vehicle controller. The transmission includes a clutch and a synchronizer for shifting gears. The transmission is drivingly connected to the engine through the clutch. The transmission control unit is configured to obtain the rotational speed of the input shaft of the transmission, the actual gear position, the target gear position, and the observed torque of the clutch. The on-vehicle controller is configured to receive the signals obtained by the transmission control unit, calculate the rotational speed of the synchronizing end of the synchronizer, the rotational speed of the end to be synchronized, and the residual shifting torque, and perform an analysis of the motion state of the synchronizer.

[0107] The various embodiments / implementations provided in the present application can be combined with each other without conflict. The above description is only a preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included within the protection scope of the present application.

Claims

1. A test method for the performance of a vehicle transmission synchronizer, characterized in that, The described test method is carried out in a test site, which includes a first test site and a second test site. The adhesion coefficient of the first test site is greater than that of the second test site. The second test site is connected to the first test site. The test method includes: Control the vehicle to start in the first test site and make the actual vehicle speed greater than the preset vehicle speed. Before entering the second test site from the first test site, confirm the actual gear, target gear, and the synchronizer corresponding to the target gear. Control the vehicle to enter the second test site with the actual vehicle speed greater than the preset vehicle speed. In the second test site, operate the synchronizer to perform a gear shift operation, control the vehicle to switch from the actual gear to the target gear, and judge the performance of the synchronizer by observing the operating state of the synchronizer and the change rate of the input shaft speed when the vehicle shifts gears. Among them, the actual gear refers to the current gear corresponding when the vehicle is controlled to accelerate until the actual vehicle speed is greater than the preset vehicle speed; by switching the actual gear to the target gear, the change of the maximum synchronous speed difference under the synchronous action of the synchronizer speed can be realized.

2. The test method for the performance of a vehicle transmission synchronizer according to claim 1, wherein The first test site is a flat snow road surface or a flat road surface with an adhesion coefficient greater than or equal to 0.2, and the second test site is a flat ice road surface or a flat road surface with an adhesion coefficient less than or equal to 0.

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3. The testing method according to claim 1, wherein If when the actual vehicle speed of the vehicle is greater than the preset vehicle speed and the vehicle has not reached the second test site, the vehicle slides to the second test site, and in the second test site, the actual vehicle speed of the vehicle is greater than or equal to the preset vehicle speed.

4. The test method for the performance of a vehicle transmission synchronizer according to claim 1, characterized in that, The step of operating the synchronizer to perform a gear shift operation specifically includes: Step on the brakes of the vehicle to make the input shaft speed of the gearbox of the actual gear equal to the first preset speed. Step on the brake to the bottom or control the clutch to disengage, and operate the synchronizer to shift to the middle position. When the input shaft speed of the gearbox of the target gear is equal to the second preset speed, control the synchronizer to shift to the target gear position.

5. The test method for the performance of a vehicle transmission synchronizer according to claim 1, characterized in that, Before the step of controlling the vehicle to make the actual vehicle speed greater than the preset vehicle speed, the test method includes: Start the vehicle after adjusting the vehicle to a preset state.

6. The test method for the performance of a vehicle transmission synchronizer according to claim 5, characterized in that, The preset state of the vehicle includes: turning off the ESC / ABS function and the TCU's diagnosis of the ABS-related function.

7. The test method for the performance of a vehicle transmission synchronizer according to claim 1, characterized in that The test method includes: Obtain the actual vehicle speed of the vehicle, the gear signal of the gearbox, the engine speed, the input shaft speed of the gearbox, and the position signal of the shift control mechanism. Analyze the gear speed corresponding to the maximum synchronous speed difference between the synchronous end and the driven end of the synchronizer corresponding to the target gear.

8. The test method for the performance of a vehicle transmission synchronizer according to claim 1, characterized in that, When the maximum synchronous speed difference of the synchronizer is in the first preset value condition, the number of gear shift operations is greater than or equal to 2.

9. According to the test method according to any one of claims 1 to 8, the vehicle includes: An engine; A gearbox, including a clutch and a synchronizer for shifting gears. The gearbox is drivingly connected to the engine through the clutch; A gearbox control unit for obtaining the input shaft speed of the gearbox, the actual gear, the target gear, and the observed torque of the clutch. A vehicle-mounted controller is used to receive the signals obtained by the transmission control unit, calculate the rotational speed of the synchronization end, the rotational speed of the end to be synchronized, and the shift residual torque of the synchronizer, and analyze the motion state of the synchronizer.

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