A test method for cooling performance of a vehicle retarder

Abstract

The application provides a test method for cooling performance of a vehicle retarder, comprising the following steps: placing the vehicle on a chassis dynamometer in an environmental chamber, adjusting temperature parameters and humidity parameters of the environmental chamber to simulate an outdoor environment; setting a gear of the retarder of the vehicle to a constant speed gear, adjusting a slope parameter of the chassis dynamometer to a first preset slope to simulate a driving slope of the vehicle, and controlling the vehicle to drive at a first preset vehicle speed; recording a vehicle speed, a driving time of the vehicle, a driving mileage of the vehicle and an inlet-outlet temperature difference of the retarder cooling liquid during the driving of the vehicle at the first preset vehicle speed; and generating an analysis result according to the vehicle speed, the driving time of the vehicle, the driving mileage of the vehicle and the inlet-outlet temperature difference of the retarder, wherein the analysis result is used to represent whether the cooling performance of the retarder meets a design index. According to the test requirements, the environmental conditions and the road conditions are adjusted, the test variables are accurately controlled, and the test results are prevented from being affected by the external environment and the road conditions.

Description

Technical Field

[0001] This invention relates to the technical field of retarder testing, and more specifically, to a method for testing the cooling performance of a vehicle retarder. Background Technology

[0002] With the development of the automotive industry, the use of retarders has become increasingly important in ensuring safe driving. Retarders can effectively assist vehicle braking and reduce wear on the braking system.

[0003] Existing methods for testing the cooling performance of retarders have many shortcomings. For example, traditional road tests are greatly affected by environmental factors such as weather and road conditions, making it difficult to ensure the consistency of test conditions. In addition, it is difficult to accurately control test variables in road tests, which affects the accuracy and reliability of test data.

[0004] There is currently no effective solution to the technical problem of inaccurate retarder cooling performance testing. Summary of the Invention

[0005] The main objective of this invention is to provide a method for testing the cooling performance of a vehicle retarder, thereby solving the technical problem of inaccurate testing of retarder cooling performance.

[0006] To achieve the above objectives, according to one aspect of the present invention, a method for testing the cooling performance of a vehicle retarder is provided, comprising: placing a vehicle on a chassis dynamometer in an environmental chamber, adjusting the temperature and humidity parameters of the environmental chamber to simulate an outdoor environment; setting the vehicle's retarder to a constant speed setting, adjusting the slope parameter of the chassis dynamometer to a first preset slope to simulate the vehicle's driving slope, and controlling the vehicle to travel at a first preset speed; recording the vehicle speed, driving time, mileage, and inlet / outlet temperature difference of the retarder coolant during the vehicle's travel at the first preset speed; generating analysis results based on the vehicle speed, driving time, mileage, and inlet / outlet temperature difference of the retarder, wherein the analysis results are used to characterize whether the retarder's cooling performance meets the design specifications.

[0007] Furthermore, while the vehicle is traveling at a first preset speed, the vehicle's auxiliary braking is activated, wherein the auxiliary braking includes at least: engine braking and exhaust braking.

[0008] Furthermore, while the vehicle is traveling at the first preset speed, the vehicle engine's cooling system is activated.

[0009] Furthermore, the vehicle is fully loaded while traveling at the first preset speed.

[0010] Furthermore, before controlling the vehicle to travel at the first preset speed, the process includes: controlling the vehicle to travel at the second preset speed for the first preset distance to preheat the vehicle, wherein the second preset speed is greater than the first preset speed; after the vehicle has traveled the first preset distance, the vehicle's driving gears are adjusted step by step until the vehicle speed is adjusted to the first preset speed, wherein at the first preset speed, the engine speed is greater than or equal to the engine speed corresponding to the engine's torque point and less than or equal to the engine speed corresponding to the engine's power point.

[0011] Furthermore, based on the vehicle speed, vehicle travel time, vehicle mileage, and the temperature difference between the inlet and outlet of the retarder coolant, analysis results are generated, including: comparing the vehicle's first real-time speed within a second preset mileage with a first preset speed; and generating a first analysis result when the first real-time speed equals the first preset speed. The first analysis result is used to characterize that the retarder's cooling performance meets the design specifications.

[0012] Furthermore, based on the vehicle speed, vehicle travel time, vehicle mileage, and the inlet and outlet temperature difference of the retarder, analysis results are generated, including: comparing the inlet temperature and outlet temperature of the retarder coolant within the vehicle's preset travel time; and generating a second analysis result when the inlet temperature difference of the retarder coolant is less than the temperature difference threshold. The second analysis result is used to characterize that the cooling performance of the retarder meets the design specifications.

[0013] Furthermore, the test method also includes: while the vehicle is traveling at a first preset speed, comparing the vehicle's second real-time speed with a third preset speed, wherein the third preset speed is greater than the first preset speed; when the second real-time speed is greater than the third preset speed, controlling the chassis dynamometer to adjust the driving slope to 0°.

[0014] Furthermore, the test method also includes: while the vehicle is traveling at a first preset speed, comparing the real-time temperature of the retarder coolant with the maximum allowable water temperature of the retarder; if the real-time temperature is greater than the maximum allowable water temperature, controlling the chassis dynamometer to adjust the driving gradient to 0°.

[0015] Furthermore, the testing method also includes: after the retarder coolant has cooled to a safe water temperature, adjusting the slope parameter of the chassis dynamometer to a second preset slope, wherein the second preset slope is less than the first preset slope.

[0016] The technical solution of this invention involves placing a vehicle within an environmental chamber using a chassis dynamometer. By adjusting the dynamometer's slope parameters to simulate the vehicle's driving gradient on a road, and adjusting the temperature and humidity parameters of the environmental chamber to simulate a real outdoor environment, the vehicle is controlled to travel at a first preset speed. The cooling performance of the retarder is measured by the vehicle speed, driving time, driving distance, and the temperature difference between the inlet and outlet of the retarder coolant. In this solution, environmental and road conditions can be adjusted according to testing requirements, precisely controlling test variables, ensuring consistency of test conditions, and avoiding the influence of external environment and road conditions on test results, thereby making the test results accurate and reliable. Attached Figure Description

[0017] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0018] Figure 1 A schematic flowchart of a first embodiment of a test method for the cooling performance of a retarder according to the present invention is shown;

[0019] Figure 2 A schematic flowchart of a second embodiment of a test method for the cooling performance of a retarder according to the present invention is shown. Detailed Implementation

[0020] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0021] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0022] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that the embodiments of this application described herein can be implemented, for example, in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0023] Exemplary embodiments according to this application will now be described in more detail with reference to the accompanying drawings. However, these exemplary embodiments may be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein. It should be understood that these embodiments are provided so that the disclosure of this application is thorough and complete, and that the concept of these exemplary embodiments is fully conveyed to those skilled in the art. In the drawings, for clarity, the thickness of layers and regions may be exaggerated, and the same reference numerals are used to denote the same devices, and therefore their description will be omitted.

[0024] Existing methods for testing the cooling performance of retarders have many shortcomings. For example, traditional road tests are greatly affected by environmental factors such as weather and road conditions, making it difficult to ensure the consistency of test conditions. In addition, it is difficult to accurately control test variables in road tests, which affects the accuracy and reliability of test data.

[0025] To address the aforementioned problems, embodiments of this application provide the following testing methods.

[0026] Combination Figure 1 As shown, according to a specific embodiment of this application, a method for testing the cooling performance of a vehicle retarder is provided.

[0027] Specifically, the testing method includes the following steps:

[0028] Step S1: Place the vehicle on the chassis dynamometer inside the environmental chamber, and adjust the temperature and humidity parameters of the environmental chamber to simulate the outdoor environment.

[0029] Step S2: Set the vehicle's retarder to constant speed, adjust the slope parameter of the chassis dynamometer to the first preset slope to simulate the vehicle's driving slope, and control the vehicle to drive at the first preset speed.

[0030] Step S3: While the vehicle is traveling at the first preset speed, record the vehicle speed, the vehicle travel time, the vehicle mileage, and the temperature difference between the inlet and outlet of the retarder coolant.

[0031] Step S4: Based on the vehicle speed, vehicle travel time, vehicle mileage, and the temperature difference between the inlet and outlet of the retarder, generate analysis results. The analysis results are used to characterize whether the cooling performance of the retarder meets the design specifications.

[0032] In an embodiment of this application, a chassis dynamometer is placed inside an environmental chamber. The dynamometer's slope parameters are adjusted to simulate the vehicle's driving gradient on a road. The temperature and humidity parameters of the environmental chamber are adjusted to simulate a real outdoor environment. The vehicle is controlled to travel at a first preset speed. The retarder's cooling performance is measured by the vehicle speed, driving time, mileage, and the temperature difference between the retarder's inlet and outlet coolant. In this scheme, environmental and road conditions can be adjusted according to testing requirements, precisely controlling test variables, ensuring consistency of test conditions, and avoiding the influence of external environment and road conditions on test results, thereby making the test results accurate and reliable.

[0033] It should be noted that the environmental chamber is used to simulate the high temperature environment outdoors. For example, the temperature and humidity parameters of the environmental chamber are adjusted so that the temperature of the environmental chamber is controlled between 32°C and 38°C. In addition, a fan is installed in the environmental chamber, and the fan outlet is set facing directly in front of the vehicle. The fan speed is controlled according to the vehicle's driving speed to simulate the headwind of the vehicle. This headwind is used to cool the engine and the whole vehicle.

[0034] It should be further explained that the chassis dynamometer is set to road resistance simulation mode. The actual road driving resistance of the vehicle is determined according to the GB / T 27840-2011 standard. This driving resistance is applied to the vehicle through the chassis dynamometer to simulate the vehicle's driving slope. The actual road slope is -5%.

[0035] Furthermore, before testing the retarder's cooling performance, the vehicle's engine needs to be tested to ensure its operating condition. The specific testing method is as follows: record the engine's actual output power P1, where the engine's rated output power is P2. If P1 > 0.8P2, the engine is considered normal, and the retarder test continues. Testing the engine's external characteristic power is also necessary to avoid engine malfunctions affecting the retarder test results, thus ensuring more accurate retarder testing.

[0036] In one exemplary embodiment of this application, while the vehicle is traveling at a first preset speed, the vehicle's auxiliary braking is activated, wherein the auxiliary braking includes at least: engine braking and exhaust braking.

[0037] During testing, while the retarder is braking, other auxiliary brakes are activated to simulate the retarder's extreme braking conditions, meaning only partial braking of the vehicle by the retarder is required. If the retarder's cooling performance still does not meet design specifications even with other auxiliary brakes activated, the retarder's cooling performance is deemed substandard.

[0038] In one exemplary embodiment of this application, the vehicle engine cooling system is activated while the vehicle is traveling at a first preset speed.

[0039] During testing, the vehicle's thermostat was kept in the open position to allow coolant to circulate freely through the radiator, thus cooling the engine. Both external fans remained on, meaning the vehicle control system's electronic control of the fans was disabled to ensure adequate engine cooling. By activating the engine's cooling system, the heat generated by the engine was prevented from affecting the retarder's cooling performance, making the retarder's cooling performance test more accurate and reliable.

[0040] In one exemplary embodiment of this application, the vehicle is fully loaded while traveling at a first preset speed.

[0041] During the test, the vehicle was fully loaded to simulate the retarder's extreme load conditions, thereby making the retarder's cooling performance test more realistic and having practical reference value, so as to avoid the retarder causing speed imbalance or temperature imbalance due to load after being put on the vehicle.

[0042] In the embodiments of this application, before controlling the vehicle to travel at a first preset speed, the following steps are included:

[0043] Step S01: Control the vehicle to travel at a second preset speed for a first preset distance to preheat the vehicle, wherein the second preset speed is greater than the first preset speed.

[0044] It should be noted that the vehicle's maximum speed is V1. The second preset speed and the first preset mileage can be set according to actual needs. Generally, the second preset speed is 0.8V1, and the first preset mileage is not less than 20km. The vehicle is driven at a relatively high speed for a certain distance to allow the engine coolant and oil temperatures to reach normal operating temperatures. This process highly replicates a real-world scenario, making the retarder's cooling performance test more realistic and providing practical reference value.

[0045] Step S02: After the vehicle has traveled the first preset mileage, the vehicle's driving gears are adjusted step by step until the vehicle speed is adjusted to the first preset speed. At the first preset speed, the engine speed is greater than or equal to the speed corresponding to the engine's torque point and less than or equal to the speed corresponding to the engine's power point.

[0046] It should be noted that the retarder is not engaged when the vehicle is running at the second preset speed. After the retarder is engaged, the vehicle needs to be downshifted to fully utilize engine braking. Specifically, the downshifting process is as follows: After downshifting one gear, determine if the engine speed after downshifting is greater than or equal to the engine's torque point. If it is less than the torque point, continue downshifting; if it is greater than the torque point, determine if the engine speed after downshifting is less than or equal to the engine's power point. If the engine speed after downshifting is greater than or equal to the torque point and less than or equal to the power point, then continue driving normally in that gear.

[0047] In the above steps, the vehicle is preheated to simulate the real vehicle condition, making the retarder cooling performance test more realistic and reliable. The vehicle speed after the retarder is activated is adjusted by downshifting step by step, so that the engine speed is greater than or equal to the speed corresponding to the engine's torque point and less than or equal to the speed corresponding to the engine's power point, so as to make full use of engine braking and engine-assisted braking, and to realistically test the retarder's braking capacity.

[0048] In one exemplary embodiment of this application, step S4 generates analysis results based on the vehicle speed, vehicle travel time, vehicle mileage, and the inlet and outlet temperature difference of the retarder coolant, including the following steps:

[0049] The vehicle's first real-time speed within the second preset mileage is compared with the first preset speed; if the first real-time speed is equal to the first preset speed, a first analysis result is generated, which is used to characterize that the retarder's cooling performance meets the design specifications.

[0050] It should be noted that the retarder's cooling performance affects its braking performance; that is, when the retarder's temperature is too high, its braking performance will decrease. The second preset mileage is calibrated according to testing requirements, generally set at 30km. If the vehicle can maintain a constant speed at the first preset speed within the second preset mileage, it indicates that the retarder's braking performance is good, meaning that the retarder's temperature is in a balanced state during this period, and the retarder's cooling performance meets the design specifications.

[0051] Furthermore, if the first real-time vehicle speed is greater than the first preset vehicle speed within the second preset mileage, the braking performance of the retarder is unstable and the braking performance is affected by the temperature of the retarder. That is, the temperature of the retarder is in an unbalanced state during this period, meaning that the cooling performance of the retarder does not meet the design specifications.

[0052] In one exemplary embodiment of this application, step S4 generates analysis results based on the vehicle speed, vehicle travel time, vehicle mileage, and the inlet and outlet temperature difference of the retarder coolant, including the following steps:

[0053] Within a preset driving time of the vehicle, the inlet temperature and outlet temperature of the retarder coolant are compared; if the inlet temperature difference of the retarder coolant is less than the temperature difference threshold, a second analysis result is generated, which is used to characterize that the cooling performance of the retarder meets the design specifications.

[0054] It should be noted that during operation, the temperature of the retarder coolant is allowed to fluctuate slightly, but within the preset driving time, the coolant temperature will be in dynamic equilibrium. Specifically, the preset driving time can be calibrated according to testing requirements, generally not exceeding 15 minutes, and the temperature difference threshold is generally less than or equal to 1℃. That is, if the temperature difference between the inlet and outlet of the retarder coolant is less than or equal to 1℃ within the preset driving time, it indicates that the coolant temperature is balanced, meaning that the retarder's cooling performance meets the design specifications.

[0055] In one exemplary embodiment of this application, the testing method further includes: comparing a second real-time vehicle speed with a third preset vehicle speed while the vehicle is traveling at a first preset speed, wherein the third preset vehicle speed is greater than the first preset vehicle speed; and controlling the chassis dynamometer to adjust the driving slope to 0° when the second real-time vehicle speed is greater than the third preset vehicle speed.

[0056] It should be noted that during the vehicle's journey at the first preset speed, if the second real-time speed exceeds the first preset speed, the retarder's braking performance becomes unstable, as it is affected by the retarder's temperature. This indicates that the retarder's temperature is unbalanced during this period. The third preset speed is greater than the first preset speed. The third preset speed is calibrated according to testing requirements. If the second real-time speed consistently exceeds the third preset speed, it indicates a severe speed imbalance that cannot be restored to equilibrium. In this case, the chassis dynamometer will adjust the driving gradient to 0°, thus ending the test.

[0057] Furthermore, the testing method shall include: after the retarder coolant has cooled to a safe water temperature, adjusting the slope parameter of the chassis dynamometer to a second preset slope, wherein the second preset slope is less than the first preset slope.

[0058] It should be noted that the unstable braking performance of the retarder indicates that the retarder's coolant temperature is too high. After the retarder coolant cools down to a safe temperature, the retarder should be retested. This time, the driving gradient should be reduced, and the test should be repeated according to steps S1 to S4 in the above embodiment. The driving gradient should be reduced in increments of 0.3% until the vehicle's second real-time speed equals the first preset speed while the vehicle is traveling at the first preset speed.

[0059] In one exemplary embodiment of this application, the testing method further includes: comparing the real-time temperature of the retarder coolant with the maximum allowable water temperature of the retarder while the vehicle is traveling at a first preset speed; and controlling the chassis dynamometer to adjust the driving gradient to 0° when the real-time temperature is greater than the maximum allowable water temperature.

[0060] It should be noted that the temperature of the retarder coolant is allowed to fluctuate slightly during operation, but it will reach a dynamic equilibrium within the preset driving time. If the real-time temperature of the retarder coolant exceeds the maximum allowable temperature of the retarder, it indicates that the retarder is not operating properly. In this case, the chassis dynamometer will be adjusted to 0° to end the test.

[0061] Furthermore, the testing method also includes: after the retarder coolant has cooled to a safe water temperature, adjusting the slope parameter of the chassis dynamometer to a second preset slope, wherein the second preset slope is less than the first preset slope.

[0062] Specifically, after the retarder coolant has cooled to a safe water temperature, the retarder is retested. This time, the driving gradient is reduced, and the test is repeated according to steps S1 to S4 in the above embodiment. The driving gradient is reduced in increments of 0.3% until the retarder coolant temperature reaches dynamic equilibrium.

[0063] In one specific embodiment of this application, as follows: Figure 2 As shown, the test method for the cooling performance of a vehicle retarder includes the following steps:

[0064] S100: Vehicle preparation and inspection.

[0065] Specifically, it is necessary to check whether the engine's actual output power is greater than 80% of its rated power.

[0066] S200: Set the environment chamber status.

[0067] Specifically, the temperature of the environmental chamber was set to 35°C, and the speed of the fan inside the chamber was adjusted according to the vehicle speed to simulate the oncoming wind of the vehicle.

[0068] S300: Vehicle warm-up preparation.

[0069] The chassis dynamometer is set to simulate road resistance. The actual road driving resistance of the vehicle is determined according to the GB / T 27840-2011 standard. The driving resistance is applied to the vehicle through the chassis dynamometer to simulate the vehicle's driving gradient. The actual road gradient is -5%. The vehicle travels continuously for 20km at 80% of its maximum speed, and the driving gear is 11.

[0070] S400: The vehicle enters the predetermined speed and gear.

[0071] Specifically, the driver shifted the vehicle to 10th gear and the speed was 70 km / h.

[0072] S500: Determines whether the engine has reached the predetermined speed.

[0073] When the vehicle speed is 70 km / h, determine whether the engine speed is within the range of 1400-1800 r / min. If yes, proceed to S600. If no, return to S400, where the driving gear is adjusted step by step, for example, downshifting from 10th gear to 9th gear.

[0074] S600: Enter the set operating conditions to perform a retarder test.

[0075] Adjust the slope parameter of the chassis dynamometer to -5%, set the retarder to constant speed, turn on the air conditioning, auxiliary braking, open the vehicle thermostat, disable the electronic control settings of the vehicle fan, and keep the vehicle fan always on; the vehicle speed is 70km / h.

[0076] S700: Whether the zeroing condition is triggered.

[0077] When the retarder is in constant speed mode, the vehicle speed increases from 70km / h to 75km / h, entering S800.

[0078] S800: The slope parameter of the chassis dynamometer is zeroed.

[0079] S900: The gradient parameter of the chassis dynamometer is reduced by 0.3%.

[0080] The vehicle slows down to a stop under the action of resistance. After the vehicle's retarder coolant cools down, the test is restarted with other conditions unchanged. The downhill gradient is reduced by 0.3% to -4.7% and the test is restarted.

[0081] S1000: Complete the test and record the data analysis results.

[0082] Ultimately, the vehicle maintained a stable speed of 70 km / h, and the retarder coolant temperature eventually stabilized at 104.2℃.

[0083] As can be seen from the above description, the embodiments of the present invention achieve the following technical effects.

[0084] 1. A chassis dynamometer is placed in an environmental chamber. The incline parameters of the dynamometer are adjusted to simulate the vehicle's driving gradient on a road. The temperature and humidity parameters of the environmental chamber are adjusted to simulate a real outdoor environment. The vehicle is controlled to travel at a preset speed. The cooling performance of the retarder is measured by the vehicle speed, driving time, driving distance, and the temperature difference between the inlet and outlet of the retarder coolant. According to testing requirements, environmental and road conditions can be adjusted to precisely control test variables, ensuring consistency of test conditions and avoiding the influence of external environment and road conditions on test results, thus making the test results accurate and reliable.

[0085] 2. During the test, while the retarder is braking, other auxiliary brakes are activated to simulate the retarder's extreme braking conditions, meaning only the retarder needs to partially brake the vehicle. If the retarder's cooling performance still does not meet the design specifications when other auxiliary brakes are activated, the retarder's cooling performance is deemed substandard.

[0086] 3. During the test, the vehicle's thermostat is kept in the open position to allow the coolant to circulate freely through the radiator, thus cooling the engine. Both external vehicle fans are kept on at all times, meaning the vehicle control system's electronic control settings for the fans are disabled to ensure sufficient engine cooling. By activating the vehicle's engine cooling system, the heat generated by the engine is prevented from affecting the retarder's cooling performance, thereby making the retarder's cooling performance test more accurate and reliable.

[0087] 4. During the test, the vehicle is fully loaded to simulate the extreme load condition of the retarder, thereby making the cooling performance test of the retarder more realistic and having practical reference value, so as to avoid the vehicle speed imbalance or retarder temperature imbalance caused by the load after the vehicle is loaded.

[0088] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0089] In addition to the above, it should be noted that the terms "one embodiment," "another embodiment," and "embodiment" used in this specification refer to specific features, structures, or characteristics described in connection with that embodiment, which are included in at least one embodiment described in the general description of this application. The appearance of the same expression in multiple places in the specification does not necessarily refer to the same embodiment. Furthermore, when a specific feature, structure, or characteristic is described in connection with any embodiment, the intention is to suggest that implementing such a feature, structure, or characteristic in conjunction with other embodiments also falls within the scope of this invention.

[0090] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0091] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for testing the cooling performance of a vehicle retarder, characterized in that, include: The vehicle was placed on a chassis dynamometer inside an environmental chamber, and the temperature and humidity parameters of the environmental chamber were adjusted to simulate the outdoor environment. Set the vehicle's retarder to constant speed, adjust the slope parameter of the chassis dynamometer to a first preset slope to simulate the vehicle's driving slope, and control the vehicle to drive at a first preset speed. While the vehicle is traveling at a first preset speed, the vehicle speed, the vehicle travel time, the vehicle mileage, and the temperature difference between the inlet and outlet of the retarder coolant are recorded. Based on the vehicle speed, the vehicle travel time, the vehicle mileage, and the inlet and outlet temperature difference of the retarder, analysis results are generated. These analysis results are used to characterize whether the cooling performance of the retarder meets the design specifications. Based on the vehicle's speed, driving time, mileage, and the temperature difference between the inlet and outlet of the retarder coolant, analysis results are generated, including: Compare the vehicle's first real-time speed within the second preset mileage with the first preset speed; When the first real-time vehicle speed is equal to the first preset vehicle speed, a first analysis result is generated. The first analysis result is used to characterize that the cooling performance of the retarder meets the design specifications. The testing method also includes: While the vehicle is traveling at a first preset speed, the second real-time speed of the vehicle is compared with a third preset speed, wherein the third preset speed is greater than the first preset speed. When the second real-time vehicle speed is greater than the third preset vehicle speed, the chassis dynamometer is controlled to adjust the driving slope to 0°.

2. The test method according to claim 1, characterized in that, While the vehicle is traveling at the first preset speed, the vehicle's auxiliary braking is activated, wherein the auxiliary braking includes at least: engine braking and exhaust braking.

3. The test method according to claim 1, characterized in that, While the vehicle is traveling at the first preset speed, the cooling system of the vehicle engine is turned on.

4. The test method according to claim 1, characterized in that, The vehicle is fully loaded while traveling at the first preset speed.

5. The test method according to any one of claims 1-4, characterized in that, Before controlling the vehicle to travel at a first preset speed, the following steps are included: The vehicle is controlled to travel at a second preset speed for a first preset distance to preheat the vehicle, wherein the second preset speed is greater than the first preset speed; After the vehicle has traveled the first preset mileage, the vehicle's driving gears are adjusted step by step until the vehicle speed is adjusted to the first preset speed. At the first preset speed, the engine speed is greater than or equal to the engine speed corresponding to the engine's upper torque point and less than or equal to the engine speed corresponding to the engine's power point.

6. The test method according to claim 1, characterized in that, Based on the vehicle's speed, travel time, mileage, and the temperature difference between the inlet and outlet of the retarder, analysis results are generated, including: Within a preset driving time of the vehicle, the inlet temperature of the retarder coolant is compared with the outlet temperature of the retarder coolant. When the inlet temperature difference of the retarder coolant is less than the temperature difference threshold, a second analysis result is generated. The second analysis result is used to characterize that the cooling performance of the retarder meets the design specifications.

7. The test method according to claim 1, characterized in that, The testing method also includes: While the vehicle is traveling at a first preset speed, the real-time temperature of the retarder coolant is compared with the maximum allowable water temperature of the retarder. If the real-time temperature is greater than the maximum allowable water temperature, the chassis dynamometer is controlled to adjust the driving gradient to 0°.

8. The test method according to claim 1 or 7, characterized in that, The testing method also includes: After the retarder coolant cools down to a safe water temperature, the slope parameter of the chassis dynamometer is adjusted to a second preset slope, wherein the second preset slope is less than the first preset slope.

Images