A test bench and test method for 6DCT low-temperature dynamic shift test

Abstract

The application discloses a test bench and a test method for 6DCT low-temperature dynamic gear shifting, which comprises an environment bin, at least one mounting hole is arranged in the environment bin, an input shaft for connecting a 6-gear double-clutch transmission sample box is arranged in the mounting hole, a sealing unit is arranged between the mounting hole and the input shaft, one end of the input shaft is located in the environment bin, and the other end of the input shaft is located outside the environment bin, a test bench motor is in transmission connection with one end of the input shaft located outside the environment bin, and the lowest temperature in the environment bin is not higher than -40 DEG. The application can more efficiently carry out low-temperature dynamic gear shifting test of the 6DCT sample box, and the obtained data can be more accurately compared with low-temperature dynamic gear shifting test data of real vehicle cold region calibration.

Description

Technical Field

[0001] This invention belongs to the field of 6DCT low-temperature dynamic shifting test technology, and specifically discloses a test bench and test method for 6DCT low-temperature dynamic shifting test. Background Technology

[0002] Low-temperature dynamic shifting test is one of the essential test items in the functional testing of transmissions. This test is a necessary performance test conducted specifically for the structural characteristics of a 6-speed dual-clutch transmission. The test requires placing a 6-speed dual-clutch transmission sample in an environmental chamber simulating temperatures as low as -40°C to test the dynamic shifting performance of the sample. The tested 6-speed dual-clutch transmission sample generally includes two input shafts, inner and outer, which correspond to the clutches controlling their respective connections to the engine power (there are two sets of clutches, namely clutch 1 and clutch 2).

[0003] The principle of this testing method is as follows: When a certain gear in the transmission is engaged, and the clutch controlling the power transmission of that gear is also engaged, a power transmission chain from the input to the output of the transmission is formed, which is named chain 1. Then, after applying a certain wheel speed (which can be converted from vehicle speed) to the output of the transmission, chain 1 starts operating. At this time, a gear set (with multiple different gears) on the shaft corresponding to the other input shaft of the transmission is pre-engaged (according to the structure of our transmission, when one gear set in the power transmission chain involving one input shaft is engaged, the gear set in the power transmission chain involving the other input shaft has a specific and fixed correspondence, that is, which gear is pre-engaged is determined). However, the clutch controlling the power transmission of that input shaft is not engaged, and this power transmission chain is named chain 2. With both power chains operating, only the power chain on the input shaft with the clutch engaged (chain 1) can transmit power to the output of the test gearbox. Switching the clutch (chain 1 clutch changes from engaged to disengaged, and chain 2 clutch changes from disengaged to engaged) allows chain 2 to transmit power from the input shaft to the output of the test gearbox without stopping the wheels. This gear shifting process, performed without stopping, achieves dynamic gear pre-engagement and the switching of the corresponding power chain. Therefore, this test, conducted under low-temperature conditions, is called low-temperature dynamic shifting performance. The flowchart and test bench equipment suitable for this test are as follows: Figure 1 and Figure 2 As shown.

[0004] While the above method can test a 6-speed dual-clutch transmission, it has the following technical problems that urgently need to be addressed:

[0005] like Figure 2As shown, the test chamber is connected to the test bench via a half-shaft and tooling at its output end. Especially when the oil temperature in the test chamber's oil pan is -40℃, the viscosity of the oil inside the test chamber is high, resulting in a large starting torque when the test bench motor drives the output end of the test chamber. The reason is: for example, assuming the starting torque of the test chamber driven from the input shaft at -40℃ is 60Nm, if it is converted to a drive mode from the output of the test chamber, the output torque would need to be 60 multiplied by the gear ratio (assuming it's in first gear, which has the highest gear ratio, assuming it's 16); then the drive torque from the output of the test chamber would need to be 960Nm.

[0006] 960 Nm is a relatively large torque for a test bench operating under no-load conditions (without providing driving torque). The test bench motor cannot provide an equivalent 960 Nm of torque to balance the starting resistance torque of the test chamber. To protect the motor of the test bench operating under no-load conditions and to prevent the shaft connecting the motor and the test chamber from bearing excessive torque, the test bench manufacturer installs a safety clutch on the spindle connecting the test bench motor and the test chamber. This safety clutch triggers a torque alarm when the test bench experiences a sudden, abnormally large resistance torque, promptly disengaging the safety clutch to disconnect the power transmission between the test bench motor and the test chamber, preventing abnormal damage to the test bench. In actual testing, it is not recommended to set the safety clutch torque alarm value on the test bench spindle too high or to disable the alarm altogether. However, during the actual test, when the oil temperature in the sample tank's oil pan was -40℃, the test bench required a large torque to withstand the resistance torque driving the sample tank's output end. This caused the safety torque alarm of the safety clutch between the test bench motor and the sample tank's output end to be triggered due to the excessive resistance torque. This disconnected the power drive of the test bench and forced the test to be terminated, preventing the test cycle from being completed smoothly according to the test sequence.

[0007] Considering that during vehicle road testing or when users in cold regions start their vehicles, the power transmission method involves the engine connecting to the transmission input and then outputting power to the wheels; it is recommended to optimize the testing method by connecting the bench motor to the input of the test chamber via a fixture. This avoids the problem of test interruption due to excessive starting resistance torque when the test chamber oil temperature is -40℃, which occurred in the original testing method. Furthermore, the bench is driven by the test chamber input, and the starting resistance torque at this time does not exceed 100Nm, nor does it exceed the torque alarm value of the no-load function bench safety clutch (assumed to be set to 100Nm). The test will not be interrupted midway through a test cycle due to power interruption caused by the disengagement of the bench safety clutch. Actual bench testing was conducted using this method, and the entire test project can be completed normally and achieves the test results required by the original plan. Summary of the Invention

[0008] To address the technical problems existing in the prior art, this invention provides a test bench and test method for low-temperature dynamic shifting tests of 6DCTs. It can conduct low-temperature dynamic shifting tests on 6DCT prototypes more efficiently, and the acquired data can be more accurately compared with the low-temperature dynamic shifting test data calibrated for real vehicles in cold regions. At the same time, it provides a directly executable test method for subsequent low-temperature dynamic shifting tests on DCT prototypes (this method can be used as a reference to make adaptive adjustments to the operating conditions, or specific operating points can be set and tested directly according to this method), which has good practical engineering guiding significance.

[0009] This invention discloses a test bench for low-temperature dynamic shifting of a 6DCT, comprising an environmental chamber, wherein at least one mounting hole is provided in the environmental chamber, and an input shaft for connecting a 6-speed dual-clutch transmission sample box is provided in the mounting hole. A sealing unit is provided between the mounting hole and the input shaft. One end of the input shaft is located inside the environmental chamber and the other end is located outside the environmental chamber. The end of the input shaft located outside the environmental chamber is connected to a test bench motor. The minimum temperature inside the environmental chamber is not higher than -40°C.

[0010] In a preferred embodiment of the present invention, the input end of the 6-speed dual-clutch transmission prototype located in the environmental chamber is connected to the input shaft, and the two output ends of the 6-speed dual-clutch transmission prototype located in the environmental chamber are unloaded.

[0011] In a preferred embodiment of the present invention, one end of the input shaft located outside the environmental chamber is connected to a clutch, and the clutch is drivenly connected to the bench motor.

[0012] The present invention also discloses a test method for low-temperature dynamic shifting of a 6DCT bench, which uses a test bench for low-temperature dynamic shifting of a 6DCT to test the dynamic shifting performance of a 6-speed dual-clutch transmission sample at an ambient temperature of -40℃, with the transmission output speed not stopping, as the vehicle speed decreases from 0 to 70 km / h to 0.

[0013] In a preferred embodiment of the present invention, the specific steps include:

[0014] S1, the 6-speed dual-clutch transmission prototype is placed in the environmental chamber, and the input end of the 6-speed dual-clutch transmission prototype is connected to the bench motor through the input shaft;

[0015] S2, the vehicle speed gradually increases from 0km / h to 70km / h, and then gradually decreases from 70km / h to 0km / h;

[0016] S3, preset an odd power chain and an even power chain based on a 6-speed dual-clutch transmission prototype box. The power transmission path of the odd power chain is: clutch 1→input outer shaft→1 / 3 / 5 gear, i.e., gear_ODD→output vehicle speed; the power transmission path of the even power chain is: clutch 2→input inner shaft→2 / 4 / 6 gear, i.e., gear_EVEN→output vehicle speed; speed increase and decrease are performed at the input shaft rotation speed rate of n·rpm / s;

[0017] S4, gear_ODD is engaged to 1st gear, gear_EVEN is engaged to 2nd gear, the pressure of clutch 1 and 2 is 0, and the vehicle speed is 0;

[0018] S5, engage clutch 1 of the 6-speed dual-clutch transmission prototype box, disengage clutch 2 of the 6-speed dual-clutch transmission prototype box, power transmission is switched to 1st gear for power connection and transmitted to the output end, clutch 1 is set with P2 pressure, clutch 2 is set with P1 pressure, the test bench provides input rotation speed to the 6-speed dual-clutch transmission prototype box at a rate of n· until reaching n1, and the input rotation speed set by the test bench is: wherein Ig1 is the gear ratio of 1st gear of the 6-speed dual-clutch transmission prototype box, R is the wheel radius, V0 is the vehicle speed, and V0>0, keep n1 unchanged and maintain for 10s;

[0019] S6, increase the cooling flow, the test temperature is -40°C, set the flow of the cooling pump to Q4, the corresponding relationship between the flow value Q4 and the temperature shall be given through product calibration;

[0020] S7, increase the input rotation speed provided by the test bench to the prototype box to n2, wherein Ig1 is the gear ratio of 1st gear of the 6-speed dual-clutch transmission prototype box, R is the wheel radius, V2 is the vehicle speed, and V2>V0;

[0021] S8, disengage clutch 1 of the 6-speed dual-clutch transmission prototype box, engage clutch 2 of the 6-speed dual-clutch transmission prototype box, power transmission is switched to 2nd gear for power connection and transmitted to the output end, clutch 1 is set with P1 pressure, clutch 2 is set with P2 pressure, and at this time the input rotation speed of the 6-speed dual-clutch transmission prototype box provided by the test bench is n2, wherein Ig2 is the gear ratio of 2nd gear of the 6-speed dual-clutch transmission prototype box, Ig2<Ig1, then the vehicle speed at this time V3>V2>V0, R is the wheel radius, and the vehicle speed is increased from V2 to V3;

[0022] S9, switch the synchronizer of the 6-speed dual-clutch transmission prototype box to set gear_ODD to 3rd gear;

[0023] S10, disengage clutch 2 of the 6-speed dual-clutch transmission prototype box, engage clutch 1 of the 6-speed dual-clutch transmission prototype box, the power transmission is switched to 3rd gear power connection and transmitted to the output end, set clutch 1 to P2 pressure and set clutch 2 to P1 pressure, at this time the input rotation speed of the 6-speed dual-clutch transmission prototype box provided by the test bench is n2, wherein Ig3 is the gear ratio of 3rd gear of the 6-speed dual-clutch transmission prototype box, Ig3<Ig2<Ig1, then the vehicle speed V4>V3>V2>V0 at this time, R is the wheel radius, and the vehicle speed is increased from V3 to V4;

[0024] S11, switch the synchronizer of the 6-speed dual-clutch transmission prototype box to set gear_EVEN to 4;

[0025] S12, disengage clutch 1 of the 6-speed dual-clutch transmission prototype box, engage clutch 2 of the 6-speed dual-clutch transmission prototype box, the power transmission is switched to 4th gear power connection and transmitted to the output end, set clutch 1 to P1 pressure and set clutch 2 to P2 pressure, at this time the input rotation speed of the 6-speed dual-clutch transmission prototype box provided by the test bench is still n2, wherein Ig4 is the gear ratio of 4th gear of the 6-speed dual-clutch transmission prototype box, Ig4<Ig3<Ig2<Ig1, then the vehicle speed V5>V4>V3>V2>V0 at this time, R is the wheel radius, and the vehicle speed is increased from V4 to V5;

[0026] S13, switch the synchronizer of the 6-speed dual-clutch transmission prototype box to set gear_ODD to 5;

[0027] S14, switch the synchronizer of the 6-speed dual-clutch transmission prototype box to set gear_ODD to 3;

[0028] S15, disengage clutch 2 of the 6-speed dual-clutch transmission prototype box, engage clutch 1 of the 6-speed dual-clutch transmission prototype box, the power transmission is switched to 3rd gear power connection and transmitted to the output end, set clutch 1 to P2 pressure and set clutch 2 to P1 pressure, at this time the input rotation speed of the 6-speed dual-clutch transmission prototype box provided by the test bench is n2, wherein Ig3 is the gear ratio of 3rd gear of the 6-speed dual-clutch transmission prototype box, Ig4<Ig3<Ig2<Ig1, then the vehicle speed V5>V4>V3>V2>V0 at this time, R is the wheel radius, and the vehicle speed is reduced from V5 to V4;

[0029] S16, switch the synchronizer of the 6-speed dual-clutch transmission prototype box to set gear_EVEN to 2;

[0030] S17, disconnect clutch 1 of the 6-speed dual-clutch transmission prototype box, engage clutch 2 of the 6-speed dual-clutch transmission prototype box, power transmission is switched to 2nd gear power connection and transmitted to the output end, clutch 1 is supplied with P1 pressure, clutch 2 is supplied with P2 pressure, at this time, the input rotational speed provided by the test bench to the 6-speed dual-clutch transmission prototype box is n2, wherein Ig2 is the gear ratio of 2nd gear of the 6-speed dual-clutch transmission prototype box, and Ig4<Ig3<Ig2<Ig1, then at this time the vehicle speed satisfies V5>V4>V3>V2>V0, R is the wheel radius, and the vehicle speed is reduced from V4 to V3;

[0031] S18, switch the synchronizer of the 6-speed dual-clutch transmission prototype box to set gear_ODD to 1;

[0032] S19, disconnect clutch 2 of the 6-speed dual-clutch transmission prototype box, engage clutch 1 of the 6-speed dual-clutch transmission prototype box, power transmission is switched to 1st gear power connection and transmitted to the output end, clutch 1 is supplied with P2 pressure, clutch 2 is supplied with P1 pressure, at this time, the input rotational speed provided by the test bench to the 6-speed dual-clutch transmission prototype box is n2, wherein Ig1 is the gear ratio of 1st gear of the 6-speed dual-clutch transmission prototype box, and Ig4<Ig3<Ig2<Ig1, then at this time the vehicle speed satisfies V5>V4>V3>V2>V0, R is the wheel radius, and the vehicle speed is reduced from V3 to V2;

[0033] S20, the test bench reduces the input rotational speed provided to the 6-speed dual-clutch transmission prototype box to n3 at a rate of n·, wherein Ig1 is the gear ratio of 1st gear of the 6-speed dual-clutch transmission prototype box, R is the wheel radius, V1 refers to the vehicle speed, and V2>V1>V0>0), the vehicle speed is reduced from V2 to V1;

[0034] S21, set the pressure of clutch 1 to 0, set the pressure of clutch 2 to 0, disconnect the odd power chain, disconnect the even power chain, and set the flow rate of the cooling pump to 0;

[0035] S22, reduce the input rotational speed of the test bench from n3 to 0 at a rate of n·.

[0036] In a preferred embodiment of the present invention, during the test, cooling is performed for at least 6 hours before the first cycle, so as to ensure that the temperature of oil in the oil pan of the sample gearbox is cooled to the required test starting temperature before each cycle; the disengaged clutch pressure is P1 bar, and the engaged clutch pressure is P2 bar; tests are respectively carried out under the conditions that the temperature of oil in the oil pan of the sample gearbox is -40°C, -30°C, -20°C and -10°C, 5 cycles of the test sequence are operated according to the figure for each temperature group, and when the temperature of oil in the oil pan of the sample gearbox reaches the test starting temperature, the test of each cycle starts to operate; speed increasing and speed decreasing are performed at an input shaft speed rate of n·rpm / s; during the whole test process, the input shaft speed of the 6-speed dual-clutch gearbox sample is not 0, so as to ensure that gear shifting during the test is gear switching performed when the gearbox shafting is not in a stopped state; according to the forward direction of the vehicle, starting from gear_ODD=1 and gear_EVEN=2, the test is carried out by gradually increasing the vehicle speed from 0km / h to 70km / h, and then gradually decreasing the speed to 0km / h.

[0037] In a preferred embodiment of the present invention, the vehicle speed change at the output end of the 6-speed dual-clutch gearbox sample is realized according to the sequence of 1st gear → 2nd gear → 3rd gear → 4th gear → 3rd gear → 2nd gear → 1st gear for each switching, and the gear ratio relation of specific gear wheels Ig4<Ig3<Ig2<Ig1, so as to realize the vehicle speed change of 0→V0→V2→V3→V4→V5→V4→V3→V2→V1→0, 0<V0<V1<V2<V3<V4<V5.

[0038] In a preferred embodiment of the present invention, 0km / h < V0 < V1 < V2 < V3 < V4 < V5 ≤ 70km / h.

[0039] In a preferred embodiment of the present invention, the maximum flow rate of the cooling pump of the sample gearbox during the test corresponding to each test starting temperature is as follows:

[0040]

[0041] In a preferred embodiment of the present invention, during the whole test process, the rotation speed of the input shaft of the 6-speed dual-clutch gearbox sample is not 0.

[0042] The beneficial effects of this invention are as follows: This invention provides a new test method for low-temperature dynamic shifting on a 6DCT test bench. This method is based on the 6DCT test principle and combines actual bench test experience with a better simulation of real vehicle test scenarios. This invention also solves the problem that the power transmission between the test bench motor and the test bench is interrupted due to the test method (original solution: the output end of the test sample box is connected to the test bench motor respectively. At -40℃, the viscosity of the sample box oil is high. The test bench is driven by the output end, which causes the test bench to bear a large resistance torque. Because this resistance torque is too large, it is easy to cause the test bench safety clutch to automatically disengage) during the actual test, which seriously affects the integrity of the test cycle and reduces the test efficiency. Furthermore, considering that the power transmission of vehicles in actual cold regions is driven from the input end of the test box, in order to better simulate the dynamic shifting performance of vehicles in cold regions under low temperature conditions on the test bench, it is also recommended to optimize the test method to connect the test bench motor to the input end of the test box. In actual implementation, it has been proven that this optimization of the test method has indeed solved the problems of the original test method, improved the test efficiency, and the test method can better simulate the test state of the real vehicle and facilitate the comparison and analysis of test bench test data with the real vehicle cold region calibration.

[0043] Furthermore, according to Figure 2 The testing method, due to the low temperature (especially -40℃) during bench startup, requires the sample box to withstand a large resistance torque (exceptionally large for the safety limits of the bench's safety clutch), which can cause test interruptions. To address this, measures such as... Figure 3 The test method shown requires the test bench to withstand a resistance torque of less than 100 Nm (within the safety limit of the test bench safety clutch, the resistance torque is reasonable). Theoretically, it will not cause test interruption. And actual tests have proven that the actual resistance torque is indeed less than 100 Nm, and the test cycle can run smoothly to the end, thus completing the complete test conditions.

[0044] Furthermore, employing the new test structure and corresponding test method of this invention, the test bench motor is connected to the input end of the test box. It is only necessary to ensure that the vehicle speed output by the test box remains consistent in both test methods, following a test cycle sequence such as 1st gear → 2nd gear → 3rd gear → 4th gear → 3rd gear → 2nd gear → 1st gear. The specific speed values ​​and their magnitudes are consistent. The corresponding test bench input speed can be calculated using the test bench input speed formula. The final test results are: ① consistent gear change sequence; ② same output speed corresponding to the gear; ③ ability to achieve dynamic gear shifting under the same test box oil sump temperature conditions and without stopping the input shaft. The final test results are consistent after executing both test methods. Moreover, the new test method is more efficient.

[0045] Furthermore, the new testing method is consistent with the method used in actual vehicle driving, and the obtained test data can be better compared with the actual vehicle cold-weather calibration data. Attached Figure Description

[0046] Figure 1 This is a flowchart of the low-temperature dynamic shifting performance in existing technologies;

[0047] Figure 2 This is the connection method of the 6-speed dual-clutch transmission prototype box on the test bench in the existing technology;

[0048] Figure 3 This is a schematic diagram of a test bench for low-temperature dynamic shifting of 6DCT according to the present invention;

[0049] Figure 4 This is a schematic representation of the working conditions of a low-temperature dynamic shift test bench for 6DCT according to the present invention.

[0050] In the diagram: 1-Environmental chamber; 2-6-speed dual-clutch transmission prototype; 3-Input shaft; 4-Bench safety clutch; 5-Bench motor. Detailed Implementation

[0051] The technical solutions (including preferred technical solutions) of the present invention will be further described in detail below with reference to the accompanying drawings and by way of listing some optional embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0052] This invention discloses a test bench for low-temperature dynamic shifting of a 6DCT, comprising an environmental chamber 1, wherein at least one mounting hole is provided in the environmental chamber 1, and an input shaft 3 for connecting a 6-speed dual-clutch transmission sample box 2 is provided in the mounting hole. A sealing unit is provided between the mounting hole and the input shaft 3. One end of the input shaft 3 is located inside the environmental chamber 1, and the other end is located outside the environmental chamber 1. The end of the input shaft 3 located outside the environmental chamber 1 is connected to a test bench motor 5. The minimum temperature inside the environmental chamber is not higher than -40°C.

[0053] Preferably, the input end of the 6-speed dual-clutch transmission prototype 2 located in the environmental chamber 1 is connected to the input shaft 3, and the two output ends of the 6-speed dual-clutch transmission prototype 2 located in the environmental chamber 1 are unloaded.

[0054] Preferably, one end of the input shaft 3 located outside the environmental chamber 1 is connected to a bench safety clutch 4, and the bench safety clutch 4 is connected to the bench motor 5 in a transmission connection.

[0055] The present invention also discloses a test method for low-temperature dynamic shifting of a 6DCT on a test bench. The test method uses a test bench for low-temperature dynamic shifting of a 6DCT to test the dynamic shifting performance of a 6-speed dual-clutch transmission sample 2 at an ambient temperature of -40℃, with the transmission output speed not stopping, as the vehicle speed decreases from 0 to 70 km / h to 0.

[0056] Preferably, the testing process of the present invention is as follows: testing requirements → testing method → ​​bench test input conditions → evaluation criteria.

[0057] Preferably, the testing requirements of this invention are: to simulate the dynamic shifting performance of the transmission from 0 to 70 km / h and back to 0 under an ambient temperature of -40°C without stopping the output speed (consistent with the testing requirements of the original testing method). Testing method: According to the testing requirements, the test sample is placed in an environmental chamber (capable of simulating -40°C) on a test bench. The test bench motor only needs to be connected to the input end of the sample via a fixture. The output ends of the sample are in a free state (no need to connect any fixtures or equipment). The vehicle speed from 0 to 70 km / h and back to 0 is converted into the rotational speed of the test bench motor to provide the sample with different vehicle speed requirements. The shifting, clutch pressure, and coolant pump flow rates of the sample are set via communication between the sample's TCU (Transmission Control Unit) and the test bench's CAN bus, thereby enabling the test bench to control the setting of input conditions such as shifting commands, clutch pressure, and coolant pump flow rates. The connection method of the sample on the test bench is described in [details omitted]. Figure 3 As shown.

[0058] Preferably, the bench test input conditions include: ① placing the sample box in an environmental chamber that can provide a minimum ambient temperature of -40℃, and connecting the input end of the sample box to the motor of the unloaded functional bench through tooling;

[0059] ② Test parameters:

[0060] a. The vehicle speed is gradually increased from 0 km / h to 70 km / h (based on the operating conditions of -40℃, driving the actual vehicle at 70 km / h is appropriate); then the speed is gradually decreased from 70 km / h to 0 km / h;

[0061] b. During power transmission, the gearbox shifts from 1st gear → 2nd gear → 3rd gear → 4th gear → 3rd gear → 2nd gear → 1st gear (considering a maximum vehicle speed of 70km / h, 4th gear is sufficient).

[0062] c. Odd / Even Definition: This is already defined in the sample test chamber TCU software, but will be explained here. Odd-numbered powertrain: Clutch 1—Input outer shaft—1 / 3 / 5 gear (gear_ODD)—Output vehicle speed (converted to bench input speed); Even-numbered powertrain: Clutch 2—Input inner shaft—2 / 4 / 6 gear (gear_EVEN)—Output vehicle speed; After optimizing the test method so that the sample test chamber's input end is connected to the test bench, the corresponding vehicle speed needs to be converted into the input speed that the test bench needs to provide to the sample test chamber based on the gear ratio relationship of each gear.

[0063] d. Test requirements:

[0064] 1. Cool for at least 6 hours before the first cycle to ensure that the oil temperature in the sample tank sump is cooled to the required test start temperature before each cycle. The temperature settings of the environmental chamber and the test start temperature are shown in Table 1 below.

[0065] 2. The unengaged clutch pressure is P1 bar, and the engaged clutch pressure is P2 bar.

[0066] 3. Tests were conducted at oil temperatures of -40℃, -30℃, -20℃, and -10℃ in the sample tank's oil sump, with each temperature group calculated according to... Figure 4 The test sequence is run for 5 cycles. The test start temperature for each cycle is as shown in Table 1 below, meaning the test must begin after the oil temperature in the sample tank sump reaches the test start temperature;

[0067] 4. Under each test start temperature condition, the maximum flow rate of the cooling pump of the sample chamber during the test process shall be set according to Table 1 below (letters are used here to represent the actual test values, which need to be given by the calibration test of the oil temperature at the oil pan of the sample chamber and the maximum flow rate of the cooling pump).

[0068] Table 1 Maximum CCP flow rate at various sump temperatures

[0069]

[0070] 5. Speed ​​up and slow down the input shaft at a speed n (rpm / s) (the speed up and slow down can be given based on actual experience and there is no fixed requirement);

[0071] 6. Throughout the entire test, the input shaft speed of the sample box is not 0 to ensure that gear shifting during the test is performed while the gearbox shaft system is not stopped;

[0072] 7. Following the direction of vehicle travel, starting with gear _ODD=1 and gear _EVEN=2, gradually increase the speed from 0km / h to 70km / h and then gradually decrease it back to 0km / h to conduct the test.

[0073] Preferably, the specific steps include:

[0074] S1, the 6-speed dual-clutch transmission prototype 2 is placed in the environmental chamber 1, and the input end of the 6-speed dual-clutch transmission prototype 2 is connected to the bench motor 5 through the input shaft 3;

[0075] S2, the vehicle speed gradually increases from 0km / h to 70km / h, and then gradually decreases from 70km / h to 0km / h;

[0076] S3, based on the 6-speed dual-clutch transmission prototype 2, has pre-set odd-numbered and even-numbered power trains. The power transmission path of the odd-numbered power train is: clutch 1 → input outer shaft → 1 / 3 / 5 gear, i.e., gear_ODD → output vehicle speed; the power transmission path of the even-numbered power train is: clutch 2 → input inner shaft → 2 / 4 / 6 gear, i.e., gear_EVEN → output vehicle speed; acceleration and deceleration are performed at the speed rate n·rpm / s of the input shaft 3.

[0077] S4, ready (power chain not connected), gear_ODD 1, gear_EVEN 2, clutch 1 / 2 pressure 0, vehicle speed 0;

[0078] S5, engage clutch 1 of the 6-speed dual-clutch transmission prototype 2, disengage clutch 2 of the 6-speed dual-clutch transmission prototype 2, switch power transmission to 1st gear, power is connected and transmitted to the output end, clutch 1 is given P2 pressure (derived from product calibration data), clutch 2 is given P1 pressure (clutch 2 is not engaged, pressure value is derived from product calibration data), the test bench provides input speed n1 to the 6-speed dual-clutch transmission prototype 2 at a rate of n·, the test bench input speed is: Where Ig1 is the gear ratio of 1st gear in the 6-speed dual-clutch transmission sample 2, R is the wheel radius, V0 is the vehicle speed, and V0>0, keep n1 unchanged for 10s (the time can be set according to your own needs).

[0079] S6, increase cooling flow rate, test temperature is -40℃, set cooling pump flow rate to Q4, the correspondence between flow rate value Q4 and temperature needs to be provided by product calibration;

[0080] S7, increase the input speed of the sample feed box on the test bench to n2. Where Ig1 is the gear ratio of 1st gear in the 6-speed dual-clutch transmission sample 2, R is the wheel radius, V2 is the vehicle speed, and V2>V0.

[0081] S8, open clutch 1 of the 6-speed dual-clutch transmission prototype 2, and close clutch 2 of the 6-speed dual-clutch transmission prototype 2. Power transmission switches to 2nd gear, and power is transmitted to the output end. Clutch 1 is given pressure P1, and clutch 2 is given pressure P2. At this time, the input speed of the 6-speed dual-clutch transmission prototype 2 from the test bench is n2 (n2 remains unchanged, and the pressures of clutch 1 and clutch 2 are interchanged). wherein Ig2 is the gear ratio of the 2nd gear of the prototype 6-speed dual-clutch gearbox 2, Ig2<Ig1, then the vehicle speed at this time satisfies V3>V2>V0, R is the wheel radius, and the vehicle speed is increased from V2 to V3;

[0082] S9, switching the synchronizer of the prototype 6-speed dual-clutch gearbox 2, so that gear_ODD is set to 3, with other settings unchanged;

[0083] S10, opening clutch 2 of the prototype 6-speed dual-clutch gearbox 2 and engaging clutch 1 of the prototype 6-speed dual-clutch gearbox 2, power transmission is switched to 3rd gear for power connection and transmitted to the output end, clutch 1 is supplied with pressure P2, clutch 2 is supplied with pressure P1, at this time the input rotation speed provided by the test bench to the prototype 6-speed dual-clutch gearbox 2 is n2 (n2 remains unchanged, the pressures of clutch 1 / clutch 2 are exchanged), wherein Ig3 is the gear ratio of the 3rd gear of the prototype 6-speed dual-clutch gearbox 2, Ig3<Ig2<Ig1, then the vehicle speed at this time satisfies V4>V3>V2>V0, R is the wheel radius, and the vehicle speed is increased from V3 to V4;

[0084] S11, switching the synchronizer of the prototype 6-speed dual-clutch gearbox 2, so that gear_EVEN is set to 4, with other settings unchanged;

[0085] S12, opening clutch 1 of the prototype 6-speed dual-clutch gearbox 2 and engaging clutch 2 of the prototype 6-speed dual-clutch gearbox 2, power transmission is switched to 4th gear for power connection and transmitted to the output end, clutch 1 is supplied with pressure P1, clutch 2 is supplied with pressure P2, at this time the input rotation speed provided by the test bench to the prototype 6-speed dual-clutch gearbox 2 is still n2 (n2 remains unchanged, the pressures of clutch 1 / clutch 2 are exchanged), wherein Ig4 is the gear ratio of the 4th gear of the prototype 6-speed dual-clutch gearbox 2, Ig4<Ig3<Ig2<Ig1, then the vehicle speed at this time satisfies V5>V4>V3>V2>V0, R is the wheel radius, and the vehicle speed is increased from V4 to V5;

[0086] S13, switching the synchronizer of the prototype 6-speed dual-clutch gearbox 2, so that gear_ODD is set to 5, with other settings unchanged;

[0087] S14, switching the synchronizer of the prototype 6-speed dual-clutch gearbox 2, so that gear_ODD is set to 3, with other settings unchanged;

[0088] S15, disengage the clutch 2 of the sample 6-speed dual-clutch gearbox 2 and engage the clutch 1 of the sample 6-speed dual-clutch gearbox 2, power transmission is switched to 3rd gear power connection and transmitted to the output end, clutch 1 is supplied with pressure P2, and clutch 2 is supplied with pressure P1. At this time, the input speed of the sample 6-speed dual-clutch gearbox 2 provided by the test bench is n2 (n2 remains unchanged, and the pressures of clutch 1 / clutch 2 are exchanged), wherein Ig3 is the gear ratio of 3rd gear of the sample 6-speed dual-clutch gearbox 2, Ig4<Ig3<Ig2<Ig1, then the vehicle speed at this time satisfies V5>V4>V3>V2>V0, R is the wheel radius, and the vehicle speed decreases from V5 to V4;

[0089] S16, switch the synchronizer of the sample 6-speed dual-clutch gearbox 2, so that gear_EVEN is set to 2, and other settings remain unchanged;

[0090] S17, disengage the clutch 1 of the sample 6-speed dual-clutch gearbox 2 and engage the clutch 2 of the sample 6-speed dual-clutch gearbox 2, power transmission is switched to 2nd gear power connection and transmitted to the output end, clutch 1 is supplied with pressure P1, and clutch 2 is supplied with pressure P2. At this time, the input speed of the sample 6-speed dual-clutch gearbox 2 provided by the test bench is n2 (n2 remains unchanged, and the pressures of clutch 1 / clutch 2 are exchanged), wherein Ig2 is the gear ratio of 2nd gear of the sample 6-speed dual-clutch gearbox 2, Ig4<Ig3<Ig2<Ig1, then the vehicle speed at this time satisfies V5>V4>V3>V2>V0, R is the wheel radius, and the vehicle speed decreases from V4 to V3;

[0091] S18, switch the synchronizer of the sample 6-speed dual-clutch gearbox 2, so that gear_ODD is set to 1, and other settings remain unchanged;

[0092] S19, disengage the clutch 2 of the sample 6-speed dual-clutch gearbox 2 and engage the clutch 1 of the sample 6-speed dual-clutch gearbox 2, power transmission is switched to 1st gear power connection and transmitted to the output end, clutch 1 is supplied with pressure P2, and clutch 2 is supplied with pressure P1. At this time, the input speed of the sample 6-speed dual-clutch gearbox 2 provided by the test bench is n2 (n2 remains unchanged, and the pressures of clutch 1 / clutch 2 are exchanged), wherein Ig1 is the gear ratio of 1st gear of the sample 6-speed dual-clutch gearbox 2, Ig4<Ig3<Ig2<Ig1, then the vehicle speed at this time satisfies V5>V4>V3>V2>V0, R is the wheel radius, and the vehicle speed decreases from V3 to V2;

[0093] S20, the test bench reduces the input speed provided to the sample 6-speed dual-clutch gearbox 2 to n3 at a rate of ṅ, wherein Ig1 is the gear ratio of the first gear of the 6-speed dual-clutch transmission sample box 2, R is the wheel radius, V1 refers to the vehicle speed, and V2>V1>V0>0, the vehicle speed decreases from V2 to V1;

[0094] S21, set the pressure of clutch 1 to 0, set the pressure of clutch 2 to 0, disconnect the odd power train, disconnect the even power train, and set the flow rate of the cooling pump to 0;

[0095] S22, reduce the input speed of the bench from n3 to 0 at a rate of ṅ.

[0096] The specific test sequence of the present invention can be according to Figure 4 the table shown, which shows the low-temperature dynamic shifting working conditions of 6DCT after the test method of the present invention is optimized to connect the input end of the sample box with the bench; the present invention performs working condition setting based on this table. As shown in Figure 4 , the corresponding necessary test input parameters in the table are replaced by letter variables. According to actual engineering experience data, this method suggests the process of gradually increasing the test vehicle speed from 0 to 70km / h and then gradually decreasing it to 0, wherein the setting of 70km / h is related to the test environment temperature. For 0→70km / h, this method divides the vehicle speed into zones, and sets the vehicle speed change according to 0→V0→V2→V3→V4→V5→V4→V3→V2→V1→0 (0<V0<V1<V2<V3<V4<V5). Here, according to the optimized test method (that is, the bench motor is connected to the input end of the sample box), as shown in Figure 4 , the vehicle speed still uses the same setting as that of the test method before optimization (the above Figure 2The vehicle speed is represented by the same alphabetical expressions 0, V0, V1, V2, V3, V4, V5 as in [Reference 0], indicating that regardless of the test method, the test principle of the present invention is that the size setting of the output vehicle speed remains consistent and will not be affected by the test method. The specific value of the vehicle speed shall be set according to test requirements, with the requirement of 0km / h < v0 < v1 < v2 < v3 < V4 < V5 ≤ 70km / h. After the test method is changed from connecting the bench motor to the output end of the sample box to connecting it to the input end of the sample box, the vehicle speed change at the output end of the sample box follows the sequence of 1st gear → 2nd gear → 3rd gear → 4th gear → 3rd gear → 2nd gear → 1st gear for each shift, and the vehicle speed change of 0 → V0 → V2 → V3 → V4 → V5 → V4 → V3 → V2 → V1 → 0, 0 < V0 < V1 < V2 < V3 < V4 < V5 is realized based on the relationship of gear ratios of specific gears Ig4 < Ig3 < Ig2 < Ig1. While at the input end of the sample box, only by mutually switching clutch 1 / clutch 2 under the condition that the rotation speed of n2 remains unchanged, can the vehicle speed increase and decrease caused by the gear sequence be realized. The clutch engagement (power chain connected) pressure P2 is obtained according to product calibration, and the clutch opening (power chain not connected) pressure P1 is obtained according to product calibration (P2 > P1). The setting of odd and even gears is defined by TCU software, which has been explained in the previous test method principle. The input speed provided by the bench where n1 < n3 < n2, n1, n2 and n3 herein are the same as n in the original test method (the bench motor is connected to two output ends of the sample box) i =(2.653*V i ) / R, (where R is the wheel radius, 0<V0<V1<V2<V3<V4<V5, 0<n0<n1<n2<n3<n4<n5; i=0, 1, 2, 3, 4, 5), which is irrelevant; but the specific values of V1, V2, V3, v4, v5 (v1<v2<V3<V4<V5) and the magnitude relationship therebetween are exactly the same as those in the original test method. Gear power chain change: from 1st gear → 2nd gear → 3rd gear → 4th gear → 3rd gear → 2nd gear → 1st gear (based on the present method, considering the minimum test ambient temperature of -40°C, it is sufficient to test up to 4th gear according to actual vehicle requirements, and the setting of -40°C is also set based on the fact that the minimum temperature in most areas of China can reach -40°C). The above test sequence has gone through 19 steps starting from sequence number 1, and the parameters to be set for each step are as Figure 4 shown, including gear_ODD, gear_EVEN, clutch 1 pressure, clutch 2 pressure, input speed provided by the bench (calculated from the bench input speed formula mentioned above). Figure 4In practice, the gear position does not need to be set; instead, the engagement of a specific gear train is achieved by setting the clutch 1 / 2 to P1 or P2. Furthermore, the gear position and clutch 1 / 2 pressure in the prototype TCU are already defined in the TCU software. The gear position and clutch values ​​are set via CAN communication between the prototype TCU and the test bench, allowing for settings on the host computer used for operation on the test bench to control the shifting mechanism and clutch pump pressure. The specific test parameters for ambient temperature (minimum -40℃), clutch 1 / 2 pressure (P1 or P2), vehicle speed (maximum 70km / h), test prototype gear position (only 1st, 2nd, 3rd, and 4th gears are tested), and coolant pump flow rate are obtained and set as explained above. Figure 2 and Figure 4 The explanation section and the test parameters above have already mentioned and explained their origins step by step. The temperature of the test environment chamber, the oil temperature in the oil pan during the sample chamber test (the environment chamber needs to wait long enough for the oil temperature in the sample chamber to equal the set ambient temperature), the flow rate of the sample chamber cooling pump, and the fact that the test only went up to 4th gear and the vehicle speed was only increased to 70km / h all reflect the low-temperature requirements of this test.

[0097] Evaluation criteria for this invention: After testing according to the optimized test input conditions, the obtained test data includes the input speed of the transmission, clutch 1 / clutch / 2 pressure, gear position (ODD / EVEN), transmission oil pan temperature (at the start of the test), and the flow rate of the cooling pump must be consistent with the test sequence as follows. Figure 4 The parameters set in steps 1 through 19 are the same (of similar magnitude, with very small differences that have no substantial impact on the test results).

[0098] Preferably, during the test, cooling is performed for at least 6 hours before the first cycle to ensure that the oil temperature in the sample tank sump is cooled to the required test start temperature before each cycle; the unengaged clutch pressure is P1 bar, and the engaged clutch pressure is P2 bar; tests are conducted at sample tank sump oil temperatures of -40℃, -30℃, -20℃, and -10℃, with each temperature group calculated according to... Figure 4 The test sequence runs for 5 cycles. Each cycle of the test begins when the oil temperature in the sample tank oil pan reaches the test start temperature. The speed is increased and decreased at the input shaft speed rate n·rpm / s. Throughout the test, the input shaft speed of the 6-speed dual-clutch transmission sample 2 is not 0 to ensure that the gear shifting is performed while the transmission shaft system is not stopped. Starting from gear _ODD=1 and gear _EVEN=2, the speed is gradually increased from 0km / h to 70km / h and then gradually decreased back to 0km / h according to the vehicle's forward direction.

[0099] Preferably, the vehicle speed change at the output end of the prototype 6-speed dual-clutch gearbox 2 is implemented in the order of 1st gear→2nd gear→3rd gear→4th gear→3rd gear→2nd gear→1st gear for each shift, according to the speed ratio relationship of specific gear wheels Ig4<Ig3<Ig2<Ig1, so as to achieve the vehicle speed change of 0→V0→V2→V3→V4→V5→V4→V3→V2→V1→0, where 0<V0<V1<V2<V3<V4<V5.

[0100] Preferably, 0km / h<V0<V1<V2<V3<V4<V5≤70km / h.

[0101] Preferably, the maximum flow rate of the cooling pump of the prototype gearbox corresponding to the initial temperature for each test is as follows:

[0102]

[0103] In a preferred embodiment of the present invention: throughout the entire test process, the rotation speed of the input shaft 3 of the prototype 6-speed dual-clutch gearbox 2 is not zero.

[0104] Taking a test on a prototype 6DCT gearbox as an example: the input end of the prototype gearbox is directly connected to a no-load bench motor, and an environmental chamber capable of controlling low-temperature environment is closed; according to test requirements, working conditions are set directly according to the test method disclosed in the present invention and an actual test is performed on the bench disclosed in the present invention; during the test, according to actual test experience from the case in the present patent, in a low-temperature (-40°C) environment, the resistance torque borne by the bench for driving the prototype gearbox to operate at low temperature is less than 100Nm, which will not trigger the torque alarm and disengagement of the safety clutch of the bench, thus greatly improving test efficiency; all working conditions required by the test can be tested by this method. And up to now, all subsequent low-temperature dynamic shifting tests have been performed according to this method, no abnormal conditions have been found, and the test requirements can be successfully met.

[0105] It is easily understood by those skilled in the art that the above is only a preferred embodiment of the present invention, and is not intended to limit the present invention. Any modification, combination, replacement, improvement and the like made within the spirit and principle of the present invention shall all be included in the protection scope of the present invention.

Claims

1. A test stand for low-temperature dynamic shifting testing of 6DCT, characterized in that: The system includes an environmental chamber (1) with at least one mounting hole. The mounting hole is provided with an input shaft (3) for connecting a 6-speed dual-clutch transmission prototype (2). A sealing unit is provided between the mounting hole and the input shaft (3). One end of the input shaft (3) is located inside the environmental chamber (1), and the other end is located outside the environmental chamber (1). The end of the input shaft (3) located outside the environmental chamber (1) is connected to a bench motor (5). The minimum temperature inside the environmental chamber is not higher than -40°C. The input end of the 6-speed dual-clutch transmission prototype (2) located inside the environmental chamber (1) is connected to the input shaft (3). The two output ends of the 6-speed dual-clutch transmission prototype (2) located inside the environmental chamber (1) are unloaded. One end of the input shaft (3) located outside the environmental chamber (1) is connected to a bench safety clutch (4). The bench safety clutch (4) and the bench motor (5) are connected to each other.

2. A test method for low-temperature dynamic gear shifting on a 6DCT rig, characterized in that: It used the test bench for low-temperature dynamic shifting of 6DCT as described in claim 1 to test the dynamic shifting performance of the 6-speed dual-clutch transmission prototype (2) at an ambient temperature of -40℃, with the transmission output speed not stopping, as the vehicle speed decreased from 0 to 70 km / h and then to 0. The specific steps included, S1, place the 6-speed dual-clutch transmission prototype (2) in the environmental chamber (1), and connect the input end of the 6-speed dual-clutch transmission prototype (2) to the bench motor (5) through the input shaft (3). S2, the vehicle speed gradually increases from 0 km / h to 70 km / h, and then gradually decreases from 70 km / h to 0 km / h; S3, based on the 6-speed dual-clutch transmission prototype (2), preset odd-numbered power chains and even-numbered power chains. The power transmission path of the odd-numbered power chain is: clutch 1 → input outer shaft → 1 / 3 / 5 gear, i.e., gear_ODD → output vehicle speed; the power transmission path of the even-numbered power chain is: clutch 2 → input inner shaft → 2 / 4 / 6 gear, i.e., gear_EVEN → output vehicle speed; speeding up and slowing down is performed at the speed rate n•rpm / s of the input shaft (3); S4, gear_ODD is set to 1, gear_EVEN is set to 2, clutch 1 / 2 pressure is 0, vehicle speed is 0; S5, engage clutch 1 of the 6-speed dual-clutch transmission prototype (2), disengage clutch 2 of the 6-speed dual-clutch transmission prototype (2), switch power transmission to 1st gear and transmit power to the output end. Clutch 1 is given pressure P2, clutch 2 is given pressure P1. The test bench provides input speed n1 to the 6-speed dual-clutch transmission prototype (2) at a rate of n•. The test bench gives the input speed: n1 = Ig1 ; where Ig1 is the gear ratio of the 1st gear of the 6-speed dual-clutch transmission sample box (2), R is the wheel radius, V0 is the vehicle speed, and V0>0, and n1 is kept unchanged for 10s; S6, increase cooling flow rate, test temperature is -40℃, set cooling pump flow rate to Q4, the correspondence between flow rate value Q4 and temperature needs to be provided by product calibration; S7, increase the input speed of the sample feed box on the test bench to n2, n2=Ig1 ; where Ig1 is the gear ratio of the 1st gear of the 6-speed dual-clutch transmission sample box (2), R is the wheel radius, V2 is the vehicle speed, and V2>V0; S8, open clutch 1 of the 6-speed dual-clutch transmission test box (2) and close clutch 2 of the 6-speed dual-clutch transmission test box (2). The power transmission is switched to 2nd gear and the power is transmitted to the output end. Clutch 1 is given pressure P1 and clutch 2 is given pressure P2. At this time, the input speed of the 6-speed dual-clutch transmission test box (2) given by the test bench is n2, n2=Ig2 ; where Ig2 is the gear ratio of the 2nd gear of the 6-speed dual-clutch transmission sample box (2), Ig2 < Ig1, then the vehicle speed V3 > V2 > V0 at this time, R is the wheel radius, and the vehicle speed increases from V2 to V3; S9, switch the synchronizer of the 6-speed dual-clutch transmission sample box (2) so that the gear _ODD is set to 3; S10, engage clutch 2 of the 6-speed dual-clutch transmission prototype box (2) and disengage clutch 1 of the 6-speed dual-clutch transmission prototype box (2), power transmission is switched to 3rd gear for power connection and transmitted to the output end, set clutch 1 to P2 pressure and set clutch 2 to P1 pressure, at this time, the input speed of the 6-speed dual-clutch transmission prototype box (2) provided by the test bench is n2, n2=Ig3 , wherein Ig3 is the speed ratio of the 3rd gear of the 6-speed dual-clutch transmission prototype box (2), and Ig3<Ig2<Ig1, then the vehicle speed V4>V3>V2>V0 at this time, R is the wheel radius, and the vehicle speed increases from V3 to V4; S11, switch the synchronizer of the 6-speed dual-clutch transmission sample box (2) so that the gear _EVEN is set to 4; S12, engage clutch 1 of the 6-speed dual-clutch transmission prototype (2) and disengage clutch 2 of the 6-speed dual-clutch transmission prototype (2). The power transmission is switched to 4th gear for power connection and transmitted to the output end. Clutch 1 is supplied with pressure P1, and clutch 2 is supplied with pressure P2. At this time, the input speed provided by the test bench to the 6-speed dual-clutch transmission prototype (2) is still n2=Ig4 , wherein Ig4 is the speed ratio of 4th gear of the 6-speed dual-clutch transmission prototype (2), and Ig4<Ig3<Ig2<Ig1, then the vehicle speed V5>V4>V3>V2>V0, R is the wheel radius, and the vehicle speed increases from V4 to V5; S13, switch the synchronizer of the 6-speed dual-clutch transmission sample box (2) so that the gear _ODD is set to 5; S14, switch the synchronizer of the 6-speed dual-clutch transmission sample box (2) so that the gear _ODD is set to 3; In step S15, engage clutch 2 of the 6-speed dual-clutch transmission prototype box (2) and disengage clutch 1 of the 6-speed dual-clutch transmission prototype box (2), power transmission is switched to 3rd gear for power connection and transmitted to the output end, set clutch 1 to pressure P2, and set clutch 2 to pressure P1, at this time, the input speed of the 6-speed dual-clutch transmission prototype box (2) provided by the test bench is n2=Ig3 , where Ig3 is the speed ratio of 3rd gear of the 6-speed dual-clutch transmission prototype box (2), and Ig4<Ig3<Ig2<Ig1, then the vehicle speed at this time satisfies V5>V4>V3>V2>V0, R is the wheel radius, and the vehicle speed decreases from V5 to V4; S16, switch the synchronizer of the 6-speed dual-clutch transmission sample box (2) so that the gear _EVEN is set to 2; S17, engage clutch 1 of the 6-speed dual-clutch transmission prototype box (2) and disengage clutch 2 of the 6-speed dual-clutch transmission prototype box (2), power transmission is switched to 2nd gear power on and transmitted to the output end, clutch 1 is supplied with P1 pressure, clutch 2 is supplied with P2 pressure, at this time, the input speed of the 6-speed dual-clutch transmission prototype box (2) provided by the test bench is n2, n2=Ig2 , wherein Ig2 is the gear ratio of 2nd gear of the 6-speed dual-clutch transmission prototype box (2), Ig4<Ig3<Ig2<Ig1, then the vehicle speed at this time satisfies V5>V4>V3>V2>V0, R is the wheel radius, and the vehicle speed is reduced from V4 to V3; S18, switching the synchronizer of the 6-speed dual-clutch transmission prototype (2), so that gear_ODD is set to 1; S19, engage clutch 2 of the 6-speed dual-clutch transmission sample box (2) and disengage clutch 1 of the 6-speed dual-clutch transmission sample box (2), the power transmission is switched to 1st gear power connection and transmitted to the output end, clutch 1 is given P2 pressure, clutch 2 is given P1 pressure, at this time the input speed of the 6-speed dual-clutch transmission sample box (2) provided by the test bench is n2=Ig1 , wherein Ig1 is the gear ratio of 1st gear of the 6-speed dual-clutch transmission sample box (2), and Ig4<Ig3<Ig2<Ig1, then at this time the vehicle speed V5>V4>V3>V2>V0, R is the wheel radius, and the vehicle speed is reduced from V3 to V2; S20, the test bench is lowered at a rate of n• to provide input speed to the 6-speed dual-clutch transmission test gearbox (2) to n3=Ig1. , where Ig1 is the gear ratio of the 1st gear of the 6-speed dual-clutch transmission sample box (2), R is the wheel radius, V1 refers to the vehicle speed, and V2>V1>V0>0, the vehicle speed decreases from V2 to V1; S21, setting the pressure of clutch 1 to 0, setting the pressure of clutch 2 to 0, disconnecting the odd power chain, disconnecting the even power chain, and setting the flow rate of the cooling pump to 0; S22, reducing the input speed of the bench to 0 at a rate of n•.

3. The test method for low-temperature dynamic gear shifting of a 6DCT gantry according to claim 2, characterized in that: During the test, cool for at least 6 hours before the first cycle, to ensure that the oil temperature in the oil pan of the prototype is cooled to the required test start temperature before each cycle; the pressure of the disengaged clutch is P1 bar, and the pressure of the engaged clutch is P2 bar; tests are carried out respectively when the oil temperature in the oil pan of the prototype is -40°C, -30°C, -20°C and -10°C, each group of temperature runs 5 cycles according to the test sequence shown in the figure, and when the oil temperature in the oil pan of the prototype reaches the test start temperature, the test of each cycle starts to run; speed increasing and decreasing are carried out at the input shaft speed rate of n• rpm / s; during the whole test process, the input shaft speed of the 6-speed dual-clutch transmission prototype (2) is not 0, to ensure that shifting during the test is gear switching performed when the transmission shaft system is not in a stopped state; according to the forward direction of the vehicle, starting from gear_ODD=1 and gear_EVEN=2, the test is carried out by gradually increasing the vehicle speed from 0 km / h to 70 km / h and then gradually decreasing the speed to 0 km / h.

4. The test method for low-temperature dynamic gear shifting of a 6DCT gantry according to claim 2, characterized in that: The vehicle speed change at the output end of the 6-speed dual-clutch transmission prototype (2) is realized according to the sequence of 1st gear → 2nd gear → 3rd gear → 4th gear → 3rd gear → 2nd gear → 1st gear for each shift, and the gear ratio relation Ig4<Ig3<Ig2<Ig1 of specific gear pairs, so as to realize the vehicle speed change of 0→V0→V2→V3→V4→V5→V4→V3→V2→V1→0, 0<V0<V1<V2<V3<V4<V5.

5. The test method for low-temperature dynamic gear shifting of a 6DCT gantry according to claim 2, characterized in that: 0km / h<V0<V1<V2<V3<V4<V5≤70km / h.

6. The test method for low-temperature dynamic gear shifting of a 6DCT gantry according to claim 2, characterized in that: The maximum flow rate of the cooling pump of the prototype corresponding to each test start temperature during the test is as follows:

7. The test method for low-temperature dynamic gear shifting of a 6DCT gantry according to claim 2, characterized in that: During the whole test process, the rotation speed of the input shaft (3) of the 6-speed dual-clutch transmission prototype (2) is not 0.

Images