Gear shift test device and method for vehicle synchronizer shift system

Abstract

The application discloses a synchronous gear shifting system shifting test device and method of a vehicle, and relates to the technical field of synchronizers.The engine input shaft of the gearbox is connected with the engine, and the rotating speed of the engine is the same as that of the synchronizer gear hub, so that the rotating speed of the synchronizer gear hub can be controlled by controlling the rotating speed of the engine; two dynamometers are respectively connected with two ends of the gearbox output shaft, and the two dynamometers respectively simulate two wheels of a real vehicle; the rotating speed of the coupling gear is related to the wheel speed, and the rotating speed of the coupling gear is related to the rotating speed of the dynamometer, so that the rotating speed of the coupling gear can be controlled by controlling the rotating speed of the dynamometer; and the control system can control the engine, the two dynamometers and the gearbox to complete the shifting test of the synchronous gear shifting system, so that the shifting test of the synchronous gear shifting system does not need to be carried out on the whole vehicle, and the test is more convenient.

Description

Technical Field

[0001] This invention relates to the field of synchronizer technology, and more particularly to a test apparatus and method for a vehicle synchronizer shifting system. Background Technology

[0002] During the development of hybrid transmissions, it is necessary to conduct shift tests on the synchronizer shifting system to observe whether the system can shift gears normally and adapt to different speed differences. This allows for timely improvements to the synchronizer shifting system if the shift tests fail. Currently, shift tests of the synchronizer shifting system can be conducted after the transmission is installed in the vehicle, but this presents inconvenience due to the need for linkage with the vehicle and the requirement to disassemble and reassemble the transmission. Summary of the Invention

[0003] This invention solves the technical problem of inconvenient gear shifting tests in existing technologies by providing a gear shifting test device and method for vehicle synchronizer gear shifting systems.

[0004] On the one hand, embodiments of the present invention provide the following technical solutions:

[0005] A vehicle synchronizer shifting system shifting test device includes a control system, an engine, and two dynamometers;

[0006] The engine is connected to the engine input shaft of the gearbox, and the two dynamometers are respectively connected to both ends of the gearbox output shaft;

[0007] The control system is connected to the engine, the two dynamometers and the gearbox respectively. The control system is used to control the engine, the two dynamometers and the gearbox to complete the shift test of the synchronizer shift system of the gearbox.

[0008] On the other hand, embodiments of the present invention also provide the following technical solutions:

[0009] A method for testing the shifting of a vehicle synchronizer shifting system, applied to the control system described above, the method comprising:

[0010] Obtain the set target speed difference and the dynamometer target speed, and determine the engine target speed based on the target speed difference and the dynamometer target speed;

[0011] The dynamometer speed is controlled to reach the target speed of the dynamometer, the engine speed is controlled to reach the target speed of the engine, the engine torque is lower than the preset torque threshold, and the gearbox is in neutral.

[0012] A gear shifting command is sent to the transmission, and the gear shifting result is determined after a first duration following the sending of the gear shifting command.

[0013] Preferably, determining the engine target speed based on the target speed difference and the dynamometer target speed includes:

[0014] Obtain the second product of the target speed of the dynamometer and the speed ratio of the gearbox, and determine the sum of the second product and the difference between the target speed and the target speed as the target speed of the engine.

[0015] Preferably, determining the engine target speed based on the target speed difference and the dynamometer target speed includes:

[0016] Obtain the second product of the target speed of the dynamometer and the speed ratio of the gearbox, and determine the difference between the second product and the target speed difference as the target speed of the engine.

[0017] Preferably, controlling the engine speed to reach the target engine speed and the engine torque to be lower than the preset torque threshold includes:

[0018] Obtain the set initial idle speed of the engine, and determine the initial speed of the dynamometer based on the initial idle speed of the engine;

[0019] The engine is controlled to enter a coupling state with the dynamometer, and after the speed of the dynamometer reaches the initial speed, the coupling state between the engine and the dynamometer is decoupled.

[0020] Control the engine speed to reach the target engine speed. After the engine has warmed up and the outlet water temperature has reached the target temperature, lock the engine throttle opening and keep it unchanged.

[0021] Preferably, after the dynamometer reaches its target speed, the engine reaches its target speed, the engine torque is below a preset torque threshold, and the transmission is in neutral, a gear shift command is sent to the transmission. Before determining the gear shift result after a first duration following the sending of the gear shift command, the method further includes:

[0022] Obtain the third product of the dynamometer's rotational speed and the gearbox's speed ratio, and determine whether the difference between the third product and the engine's rotational speed is lower than the target rotational speed difference and whether the engine's torque is lower than the preset torque threshold.

[0023] If the difference between the third product and the engine speed is lower than the target speed difference, and the engine torque is lower than the preset torque threshold, then the step of sending a gear shift command to the transmission and determining the gear shift result after a first duration of sending the gear shift command is executed.

[0024] Preferably, determining the gear shift result includes:

[0025] Obtain the first target angle of the shift drum corresponding to the shift command and the actual angle of the shift drum of the synchronizer shift system;

[0026] If the angle difference between the first target angle and the actual angle is lower than a preset first angle difference threshold, then the gear shifting result is determined to be a successful gear shift; otherwise, the gear shifting result is determined to be a failed gear shift.

[0027] Preferably, after sending a gear shift command to the transmission and determining the gear shift result after a first duration following sending the gear shift command, the method further includes:

[0028] If the gear shift result is successful, then determine whether the total torque of the dynamometer is less than the first product of the engine torque and the gearbox speed ratio;

[0029] If the total torque of the dynamometer is less than the first product, a disengagement command is sent to the gearbox, and the disengagement result is determined after a second time interval following the sending of the disengagement command.

[0030] Preferably, determining the removal result includes:

[0031] Obtain the second target angle of the shift drum corresponding to the disengagement command and the actual angle of the shift drum of the synchronizer shift system;

[0032] If the angle difference between the second target angle and the actual angle is lower than the preset second angle difference threshold, then the gear disengagement result is determined to be successful; otherwise, the gear disengagement result is determined to be unsuccessful.

[0033] Preferably, if the total torque of the dynamometer is less than the first product, a disengagement command is sent to the gearbox, and after a second time interval following the sending of the disengagement command, and after determining the disengagement result, the method further includes:

[0034] If the gear shifting result is successful, then the shift count of the synchronizer shifting system is incremented by one;

[0035] If the number of gear shifts is less than the target number, the next gear shift test will be conducted three hours after the successful disengagement of the gear.

[0036] One or more technical solutions provided by this invention have at least the following technical effects or advantages:

[0037] In this invention, the engine is connected to the engine input shaft of the gearbox, and the engine speed is the same as the synchronizer hub speed. Thus, controlling the engine speed controls the synchronizer hub speed. Two dynamometers are connected to both ends of the gearbox output shaft, simulating two wheels of a real vehicle. The speed of the gear engagement is related to the wheel speed, and therefore the speed of the gear engagement is related to the speed of the dynamometer. Thus, controlling the speed of the dynamometer controls the speed of the gear engagement. The control system can control the engine, the two dynamometers, and the gearbox to complete the shift test of the synchronizer shift system. Therefore, the shift test of the synchronizer shift system does not need to be performed on the entire vehicle, making the test more convenient. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0039] Figure 1 This is a schematic diagram of the structure of the vehicle synchronizer shifting system shifting test device in an embodiment of the present invention;

[0040] Figure 2 This is a flowchart of the vehicle synchronizer shifting system shifting test method in an embodiment of the present invention. Detailed Implementation

[0041] The present invention provides a test apparatus and method for a vehicle synchronizer shifting system, thereby solving the technical problem of inconvenience in testing vehicle synchronizer shifting systems in the prior art.

[0042] To better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0043] like Figure 1 As shown, the vehicle synchronizer shifting system shifting test device of this embodiment includes a control system, an engine, and two dynamometers;

[0044] The engine is connected to the gearbox via the engine input shaft, and two dynamometers are connected to the two ends of the gearbox output shaft, respectively.

[0045] The control system is connected to the engine, two dynamometers, and the gearbox. The control system is used to control the engine, the two dynamometers, and the gearbox to complete the shift test of the gearbox synchronizer shift system.

[0046] Generally, the synchronizer shifting process involves the shifting system driving the synchronizer sleeve to eliminate the speed difference between the synchronizer hub and the two ends of the engagement teeth. In this embodiment, the engine is connected to the engine input shaft of the transmission, and the engine speed is the same as the synchronizer hub speed. Thus, controlling the engine speed controls the synchronizer hub speed. Two dynamometers are connected to the two ends of the transmission output shaft, simulating two wheels of a real vehicle. The engagement teeth speed is related to the wheel speed, and therefore the engagement teeth speed is related to the dynamometer speed. Specifically, the engagement teeth speed is the product of the dynamometer speed and the transmission speed ratio. Thus, controlling the dynamometer speed controls the engagement teeth speed. Therefore, the shifting test of the synchronizer shifting system does not need to be performed on the entire vehicle, making the test more convenient.

[0047] To illustrate in detail how the control system controls the engine, two dynamometers, and the gearbox to complete the shift test of the gearbox synchronizer shift system, such as... Figure 2 As shown, this embodiment also provides a shifting test method for a vehicle synchronizer shifting system, applied to the control system described above, including:

[0048] Step S1: Obtain the set target speed difference and dynamometer target speed, and determine the engine target speed based on the target speed difference and dynamometer target speed;

[0049] Step S2: Control the dynamometer speed to reach the dynamometer target speed, the engine speed to reach the engine target speed, the engine torque to be lower than the preset torque threshold, and the gearbox to be in neutral.

[0050] Step S3: Send a gear shift command to the transmission, and determine the gear shift result after the first duration of sending the gear shift command;

[0051] Step S4: If the gear shifting result is successful, determine whether the total torque of the dynamometer is less than the first product of the engine torque and the gearbox speed ratio.

[0052] Step S5: If the total torque of the dynamometer is less than the first product, a disengagement command is sent to the gearbox, and the disengagement result is determined after a second time interval following the sending of the disengagement command.

[0053] In step S1, the target speed difference is manually set, for example, 50 rpm. The smaller the target speed difference, the more stringent the requirements for the shifting performance of the synchronizer shifting system. Automakers can set the target speed difference according to the performance requirements of the synchronizer shifting system. The dynamometer target speed is the speed control target of the dynamometer, and the engine target speed is the speed control target of the engine.

[0054] Generally, before shifting gears with a synchronizer, the speed difference between the synchronizer hub and the engaging teeth must be lower than the target speed difference. In this embodiment, this means ensuring that the speed difference between the product of the dynamometer target speed and the gearbox ratio, and the engine target speed, is lower than the target speed difference. Here, the speed difference is an absolute value; therefore, the product of the dynamometer target speed and the gearbox ratio can be greater than or less than the engine target speed. Therefore, step S1, determining the engine target speed based on the target speed difference and the dynamometer target speed, can include:

[0055] Obtain the second product of the dynamometer target speed and the gearbox speed ratio, and determine the engine target speed as the sum of the second product and the difference between the target speed and the target speed; at this time, the determined engine target speed is greater than the second product.

[0056] Determining the engine target speed based on the target speed difference and the dynamometer target speed may also include:

[0057] Obtain the second product of the dynamometer target speed and the gearbox speed ratio, and determine the engine target speed as the difference between the second product and the target speed difference; at this time, the determined engine target speed is less than the second product.

[0058] As mentioned above, before the synchronizer shifts gears, the difference between the product of the dynamometer's speed and the gearbox ratio, and the engine's speed, must be lower than the target speed difference. Therefore, in step S2, the dynamometer's speed needs to reach the target dynamometer speed, and the engine's speed needs to reach the target engine speed. Before the synchronizer shifts gears, the engine torque also needs to be zero; otherwise, shifting is impossible. However, in practice, it's impossible to control the engine torque to be absolutely zero. Therefore, in step S2, the engine torque needs to be controlled below a preset torque threshold, which can be 5 Nm. An engine torque below 5 Nm is equivalent to being close to zero. Furthermore, gearbox shifting involves moving from neutral to the target gear (engaging) and then moving from the target gear back to neutral (disengaging).

[0059] In step S2 of this embodiment, controlling the engine speed to reach the target engine speed and the engine torque to be lower than a preset torque threshold may specifically include:

[0060] Obtain the set initial idle speed of the engine, and determine the initial speed of the dynamometer based on the initial idle speed of the engine and the speed ratio;

[0061] The engine and dynamometer are coupled together, and the coupling is released after the dynamometer reaches its initial speed.

[0062] Control the engine speed to reach the target engine speed. After the engine has warmed up and the coolant temperature has reached the target temperature, lock the engine throttle opening and keep it unchanged.

[0063] The initial idle speed of the engine is set within the range of 800-1000 rpm, and the target temperature can be 85℃. The ratio of the initial idle speed to the gear ratio can be used as the initial speed of the dynamometer. After the engine and dynamometer are coupled, the dynamometer speed is controlled to reach the initial speed, and the engine speed will then reach the initial idle speed, starting the engine. Next, the engine speed is controlled to reach the target speed. Once the engine has warmed up and the coolant temperature reaches the target temperature, the throttle opening is locked and remains unchanged, causing the engine torque to fall below a preset torque threshold. This process constitutes idle speed control for engine speed and torque adjustment, ensuring that the engine speed reaches the target speed and the engine torque falls below the preset torque threshold, thus meeting the basic conditions before shifting gears.

[0064] In step S3, after sending the gear shift command to the transmission, the synchronizer shifting system engages the gear. After a first duration (1 second), the gear shift is considered complete. If the gear shift fails, the shifting test will terminate. This essentially completes the gear shifting test.

[0065] The process of determining the gear engagement result includes: acquiring the first target angle of the shift drum corresponding to the gear engagement command and the actual angle of the shift drum in the synchronizer shift system; if the angle difference between the first target angle and the actual angle is lower than a preset first angle difference threshold, the gear engagement result is determined to be successful; otherwise, the gear engagement result is determined to be unsuccessful. The first angle difference threshold can be 1°. The gear engagement command includes the target gear; for example, if the gear needs to be shifted from neutral to 1st gear, the target gear is 1st gear. The first target angle corresponding to the gear engagement command is the angle that the shift drum should have when the transmission gear is in the target gear. If the angle difference between the first target angle and the actual angle is lower than the preset first angle difference threshold, it means that the transmission gear is in the target gear, indicating successful gear engagement.

[0066] In step S5, if the total torque of the dynamometer is less than the first product, it proves that the total torque of the dynamometer and the engine torque do not affect the subsequent disengagement process, and disengagement can proceed. After sending the disengagement command to the transmission, the synchronizer shifting system disengages, and after a second duration (1 second), the disengagement is considered complete. If disengagement fails, the shifting test will be terminated. This is equivalent to completing the disengagement test.

[0067] The process of determining the gear disengagement result includes: acquiring the second target angle of the shift drum corresponding to the disengagement command and the actual angle of the shift drum in the synchronizer shift system; if the angle difference between the second target angle and the actual angle is lower than a preset second angle difference threshold, the disengagement result is determined to be successful; otherwise, the disengagement result is determined to be unsuccessful. The second angle difference threshold can be 1°. The disengagement command includes the target gear; for example, if the gear needs to be shifted from 1st gear to neutral, the target gear is neutral. The second target angle corresponding to the disengagement command is the angle that the shift drum should have when the transmission is in neutral. If the angle difference between the second target angle and the actual angle is lower than the preset second angle difference threshold, it means that the transmission is in neutral, indicating that the disengagement was successful.

[0068] As can be seen from the above, steps S1-S5 can realize the shift test of the synchronizer shift system, including the engagement test and the disengagement test.

[0069] Although step S2 of this embodiment controls the dynamometer speed, engine speed, and engine torque, it cannot guarantee that the dynamometer speed will reach the target speed, the engine speed will reach the target speed, or the engine torque will be lower than the preset torque threshold. Before shifting gears, it is necessary to ensure that the difference between the product of the dynamometer speed and the gearbox ratio, and the engine speed, is lower than the target speed difference, and that the engine torque is lower than the preset torque threshold. To ensure that the basic conditions for shifting are met, this embodiment preferably includes the following shifting test method for the vehicle synchronizer shifting system after step S2 and before step S3:

[0070] Obtain the third product of the dynamometer's speed and the gearbox's speed ratio, and determine whether the difference between the third product and the engine's speed is lower than the target speed difference and whether the engine's torque is lower than the preset torque threshold. If the difference between the third product and the engine's speed is lower than the target speed difference and the engine's torque is lower than the preset torque threshold, then execute step S3.

[0071] Generally, the shifting test of a synchronizer shifting system also includes a durability test. Therefore, in this preferred embodiment, after step S5, the vehicle synchronizer shifting system shifting test method further includes:

[0072] If the gear shift is successful, the shift count of the synchronizer shifting system is incremented by one; if the shift count is lower than the target count, the next shift test will be conducted three hours after the successful gear shift.

[0073] In this way, after each successful gear engagement and disengagement test, the shift count of the synchronizer shifting system is incremented by one, and the next shift test continues until the target number of shifts is reached, thus achieving the durability test of the synchronizer shifting system. The third duration can be zero or greater than zero, such as 3 seconds. When the third duration is zero, the synchronizer engages gears continuously, resulting in significant heat generation and a higher probability of synchronizer malfunction, making the test method in this embodiment more rigorous. When the third duration is greater than zero, the synchronizer can dissipate heat sufficiently after each successful shift, making the test method closer to the actual use of the synchronizer in a real vehicle, and the durability test results more representative.

[0074] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0075] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A test method for a vehicle synchronizer shifting system, applied to a test apparatus for a vehicle synchronizer shifting system, characterized in that, The method includes: Obtain the set target speed difference and the dynamometer target speed, and determine the engine target speed based on the target speed difference and the dynamometer target speed; The dynamometer speed is controlled to reach the target speed of the dynamometer, the engine speed is controlled to reach the target speed of the engine, the engine torque is lower than the preset torque threshold, and the gearbox is in neutral. Send a gear shift command to the transmission, and determine the gear shift result after a first duration following the sending of the gear shift command; If the gear shift result is successful, then determine whether the total torque of the dynamometer is less than the first product of the engine torque and the gearbox speed ratio; If the total torque of the dynamometer is less than the first product, a disengagement command is sent to the gearbox, and the disengagement result is determined after a second time interval following the sending of the disengagement command; The vehicle synchronizer shifting system shifting test device includes a control system, an engine, and two dynamometers; the engine is connected to the engine input shaft of the gearbox, and the two dynamometers are respectively connected to the two ends of the gearbox output shaft; the control system is connected to the engine, the two dynamometers, and the gearbox, and the control system is used to control the engine, the two dynamometers, and the gearbox to complete the shifting test of the synchronizer shifting system of the gearbox; The determination of the gear shifting result includes: obtaining the first target angle of the shift drum corresponding to the gear shifting command and the actual angle of the shift drum of the synchronizer shifting system; if the angle difference between the first target angle and the actual angle is lower than a preset first angle difference threshold, the gear shifting result is determined to be successful; otherwise, the gear shifting result is determined to be failed. The gear shifting command includes the target gear, and the first target angle is the angle of the shift drum when the gearbox is in the target gear.

2. The vehicle synchronizer shifting system shifting test method as described in claim 1, characterized in that, Determining the engine target speed based on the target speed difference and the dynamometer target speed includes: Obtain the second product of the target speed of the dynamometer and the speed ratio of the gearbox, and determine the sum of the second product and the difference between the target speed and the target speed as the target speed of the engine.

3. The vehicle synchronizer shifting system shifting test method as described in claim 1, characterized in that, Determining the engine target speed based on the target speed difference and the dynamometer target speed includes: Obtain the second product of the target speed of the dynamometer and the speed ratio of the gearbox, and determine the difference between the second product and the target speed difference as the target speed of the engine.

4. The vehicle synchronizer shifting system shifting test method as described in claim 1, characterized in that, Controlling the engine speed to reach the target engine speed and the engine torque to be lower than the preset torque threshold includes: Obtain the set initial idle speed of the engine, and determine the initial speed of the dynamometer based on the initial idle speed of the engine; The engine is controlled to enter a coupling state with the dynamometer, and after the speed of the dynamometer reaches the initial speed, the coupling state between the engine and the dynamometer is decoupled. Control the engine speed to reach the target engine speed. After the engine has warmed up and the outlet water temperature has reached the target temperature, lock the engine throttle opening and keep it unchanged.

5. The vehicle synchronizer shifting system shifting test method as described in claim 1, characterized in that, After the dynamometer reaches its target speed, the engine reaches its target speed, the engine torque is below a preset torque threshold, and the transmission is in neutral, a gear shift command is sent to the transmission. Before determining the gear shift result after a first duration following the sending of the gear shift command, the method further includes: Obtain the third product of the dynamometer's rotational speed and the gearbox's speed ratio, and determine whether the difference between the third product and the engine's rotational speed is lower than the target rotational speed difference and whether the engine's torque is lower than the preset torque threshold. If the difference between the third product and the engine speed is lower than the target speed difference, and the engine torque is lower than the preset torque threshold, then the step of sending a gear shift command to the transmission and determining the gear shift result after a first duration of sending the gear shift command is executed.

6. The vehicle synchronizer shifting system shifting test method as described in claim 1, characterized in that, The determination of the removal result includes: Obtain the second target angle of the shift drum corresponding to the disengagement command and the actual angle of the shift drum of the synchronizer shift system; If the angle difference between the second target angle and the actual angle is lower than the preset second angle difference threshold, then the gear disengagement result is determined to be successful; otherwise, the gear disengagement result is determined to be unsuccessful.

7. The vehicle synchronizer shifting system shifting test method as described in claim 1, characterized in that, If the total torque of the dynamometer is less than the first product, a disengagement command is sent to the gearbox, and after a second time interval following the sending of the disengagement command, and after determining the disengagement result, the following steps are also included: If the gear shifting result is successful, then the shift count of the synchronizer shifting system is incremented by one; If the number of gear shifts is less than the target number, the next gear shift test will be conducted three hours after the successful disengagement of the gear.

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