Platform and method for testing performance of power transmission system of crawler-type amphibious vehicle

Abstract

The invention discloses a crawler-type amphibious vehicle power transmission system performance test platform and a crawler-type amphibious vehicle power transmission system performance test method. The test platform comprises a test bench main control system, and an electric dynamometer, a bevel gear box, an air inlet air conditioner, an oil supply system, a low-voltage power supply and control system, a smoke exhaust system, a data acquisition system and a seawater simulation device which are connected with the test bench main control system through a bus. The air inlet air conditioner, the oil supply system, the low-voltage power supply and control system, the smoke exhaust system and the data acquisition system are all connected with a tested power transmission system engine and an auxiliary system thereof; when an onshore working condition simulation test is carried out, the two electric dynamometers which are oppositely arranged are respectively connected with the power output end of an onshore transmission box of a tested power transmission system; when an overwater working condition simulation test is carried out, the two electric dynamometers which are oppositely arranged are respectively connected with the power output end of the overwater transmission box of the tested power transmission system through the bevel gear boxes, and meanwhile, the seawater simulation device cools the tested power transmission system. According to the invention, land driving conditions and water driving conditions can be simulated, and output characteristics of the power transmission system can be obtained.

Description

Technical Field

[0001] The present invention relates to the technical field of test devices, and particularly to a performance test platform and method for the power transmission system of a tracked amphibious vehicle. Background Art

[0002] The power transmission system is the core of the vehicle chassis, and its performance directly affects the overall vehicle's mobility and battlefield adaptability. For amphibious vehicles, the power transmission system must not only enable the vehicle to travel stably and efficiently on land but also be able to propel quickly and safely in water. Therefore, the power performance, stability, reliability, and environmental adaptability of the power transmission system are crucial. Currently, China is independently developing a vehicle power assembly with small size, light weight, high reliability, rapid response, sensitive steering, and flexible layout. With the excellent mobility performance and the expansion of the power transmission system functions, it has also led to a complex structure of the power transmission system, high system matching requirements, and a doubling of the test and verification needs. To complete the verification of the power transmission system functions and performance parameters, full-vehicle on-land and on-water working condition actual vehicle tests must be carried out during the R & D process. Due to the large number of test verification items and high test difficulty, the cost of actual vehicle tests has increased significantly, and the development cycle has been correspondingly lengthened. Therefore, there is an urgent need to establish a power transmission system performance test platform to carry out performance tests in the laboratory environment to replace the field tests and provide guidance for the performance verification and optimization improvement of the power transmission system. Summary of the Invention

[0003] In view of this, the present invention provides a performance test platform and method for the power transmission system of a tracked amphibious vehicle, which can simulate on-land driving conditions and on-water driving conditions and obtain the output characteristics of the power transmission system.

[0004] The technical solution adopted by the present invention is as follows:

[0005] A performance test platform for the power transmission system of a tracked amphibious vehicle includes a main control system of the test bench and an electric dynamometer, a bevel gear box, an intake air conditioner, a fuel supply system, a low-voltage power supply and control system, a smoke exhaust system, a data acquisition system, and a seawater simulation device connected to it through a bus;

[0006] The intake air conditioner, the fuel supply system, the low-voltage power supply and control system, the smoke exhaust system, and the data acquisition system are all connected to the engine and its auxiliary systems of the power transmission system under test; when conducting on-land condition simulation tests, two relatively arranged electric dynamometers are respectively connected to the power output ends of the on-land transmission case of the power transmission system under test; when conducting on-water condition simulation tests, two relatively arranged electric dynamometers are respectively connected to the power output ends of the on-water transmission case of the power transmission system under test through the bevel gear box. At the same time, the seawater simulation device cools the power transmission system under test.

[0007] The present invention also provides a method for testing the performance of a power transmission system of a tracked amphibious vehicle. Using the above test platform, the test method includes the following steps:

[0008] There is no specific order for the on-land working condition test and the water working condition test. If the on-land working condition test is to be carried out, the following operations shall be taken:

[0009] Step 1: Set up the test platform and start each test equipment;

[0010] Step 2: Start the engine of the power transmission system to be tested and fully preheat the power transmission system;

[0011] Step 3: Set the target values of the engine intake air temperature and exhaust back pressure, and use the intake air conditioner and the exhaust smoke system to automatically adjust the temperature and pressure;

[0012] Step 4: Switch the on-land transmission box gears of the power transmission system to be tested, and switch in the order of forward gears first and then reverse gears, and low gears first and then high gears;

[0013] Step 5: According to the maximum output speed and the minimum output speed of the power transmission system corresponding to the current gear, take five to ten points at equal difference series for the intermediate speed points. The electric dynamometer uses the constant speed mode to control the output speed of the power transmission system at the target speed points;

[0014] Step 6: Adjust the throttle opening to 100%;

[0015] Step 7: When the power transmission system to be tested runs continuously for more than 30 s and the output torque fluctuation range does not exceed ±3%, record the total output torque of the power transmission system and the fuel consumption per hour;

[0016] Step 8: Switch the speed points and gears and repeat the above tests to complete the test data acquisition for all gears and various speeds;

[0017] Step 9: Calculate the effective power and fuel consumption rate at each speed point. Take the output speed of the power transmission system as the abscissa and the output torque as the ordinate, connect the data under each gear into a curve, and draw the curves of all gears on the same graph to obtain the on-land working condition output characteristic curve of the power transmission system to be tested;

[0018] If the water working condition test is to be carried out, the following operations shall be taken:

[0019] Step 1: First, set up the test platform and start each test equipment;

[0020] Step 2: Start the engine of the power transmission system to be tested and fully preheat the power transmission system;

[0021] Step 3: Set the target values of the engine intake air temperature and exhaust back pressure, and use the intake air conditioner and exhaust smoke system to automatically adjust the temperature and pressure;

[0022] Step 4: Set the target values of the simulated seawater flow rate and temperature, and use the seawater simulation device to automatically adjust the simulated seawater temperature and flow rate;

[0023] Step 5: Switch the water transmission gearbox of the tested power transmission system to the forward gear. According to the maximum output speed and minimum output speed of the power transmission system under water conditions, take five to ten points at equal difference series for each intermediate speed point. The electric dynamometer uses the constant speed mode to control the output speed of the power transmission system at the target speed point;

[0024] Step 6: Adjust the throttle opening to 100%;

[0025] Step 7: After the power transmission system runs continuously for more than 30 s and the output torque fluctuation range does not exceed ±3%, record the total output torque and fuel consumption per hour of the power transmission system;

[0026] Step 8: Switch the speed points and gears to repeat the above tests to complete the acquisition of test data for all gears and at various speeds;

[0027] Step 9: Calculate the effective power and fuel consumption rate at each speed point. Take the output speed of the power transmission system as the abscissa and the output torque as the ordinate, connect the data under each gear into a curve, and draw the curves of all gears on the same graph to obtain the output characteristic curve of the power transmission system of the tested power transmission system under water conditions.

[0028] Beneficial effects:

[0029] 1. The present invention can realize the bench simulation of the on-land use conditions and water use conditions of the power transmission system of an amphibious vehicle. Through the loading and testing of an electric dynamometer, the accurate testing of the output characteristics of the power transmission system is completed. Through the adjustment of systems such as the intake air conditioner and seawater simulation device, the performance parameters under specific temperature environments can also be obtained, and the influence of the environmental temperature on the power transmission system can be studied and analyzed. At the same time, through the rich and comprehensive testing means of the bench, problems such as unreasonable performance matching and unclear fault modes of the vehicle power, transmission, and auxiliary systems can be effectively solved, providing a platform for joint debugging, matching optimization, and performance verification of the power transmission system at all stages of vehicle development, effectively shortening the development cycle, saving the test verification cost, and providing a scientific basis for the research and technical development of the power transmission system of amphibious vehicles.

[0030] 2. The present invention uses a set of closed - loop cooling water to provide a cooling medium for the power transmission system during the water operation condition, and then the external cooling water system precisely controls the temperature of the closed - loop circulating water to form a seawater simulation condition, ensuring the smooth progress of the water operation condition simulation test. At the same time, in cooperation with the intake air conditioner to adjust the intake air temperature of the engine, it realizes the control of the ambient temperature in the water operation condition simulation test, and obtains the performance test parameters under different temperature conditions.

[0031] 3. The performance test method of the power transmission system of the present invention is simple to operate and has high test efficiency. It can respectively measure the performance parameters of the amphibious vehicle in the land operation condition and the water operation condition, and obtain the output characteristic curve. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is the schematic diagram of the water operation condition simulation test.

[0033] Figure 2 It is the schematic diagram of the land operation condition simulation test.

[0034] Among them, 1 - test bench main control system, 2 - electric dynamometer, 3 - bevel gearbox, 4 - intake air conditioner, 5 - fuel supply system, 6 - low - voltage power supply and control system, 7 - exhaust system, 8 - data acquisition system, 9 - variable - frequency water pump, 10 - water storage tank, 11 - flowmeter, 12 - water - water heat exchanger, 13 - cooling circulating water system, 14 - temperature control valve, 15 - engine and auxiliary system, 16 - main transmission box, 17 - water - borne transmission box, 18 - land - borne transmission box, 19 - seawater heat exchanger. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0035] The following combines the drawings and gives embodiments to describe the present invention in detail.

[0036] The present invention provides a performance test platform for the power transmission system of a tracked amphibious vehicle, as Figure 1 、 Figure 2 shown. The test platform includes a test bench main control system 1, an electric dynamometer 2, a bevel gearbox 3, an intake air conditioner 4, a fuel supply system 5, a low - voltage power supply and control system 6, an exhaust system 7, a data acquisition system 8, a variable - frequency water pump 9, a water storage tank 10, a flowmeter 11, a water - water heat exchanger 12, a cooling circulating water system 13, and a temperature control valve 14.

[0037] The test piece is the power transmission system of an amphibious vehicle, including an engine and auxiliary system 15, a main transmission box 16, a water - borne transmission box 17, a land - borne transmission box 18, and a seawater heat exchanger 19.

[0038] The main control system 1 of the test bench, as the display and control terminal of the test platform, connects each subsystem through a bus to establish a communication connection. During the test process, it can operate and control various devices such as the electric dynamometer 2, the fuel supply system 5, and the exhaust system 7, as well as the test piece, and at the same time monitor the device status and the test piece status.

[0039] The bevel gearbox 3 is used to transmit torque while changing the direction of the output shaft. The output shaft and the output shaft are arranged at 90°. The two bevel gearboxes 3 are arranged mirror-symmetrically. High-precision rolling bearings are installed inside the box for support, and a forced lubrication system is equipped. It can achieve forward and reverse rotation, detect the bearing temperature in real time, and has an interlock alarm function.

[0040] The electric dynamometer 2 is used to apply load and measure power for the test power transmission system. The electric dynamometer 2 has the function of four-quadrant operation to adapt to various working condition simulation tests such as vehicle forward, reverse, and central steering. The dynamometer has loading modes such as speed control, torque control, and road simulation.

[0041] The intake air conditioner 4 is connected to the inlet of the engine air filter of the test power transmission system. The intake air conditioner 4 includes a fan, a cooling system, a heating system, and a voltage stabilizing device, and can achieve control of the engine intake air temperature.

[0042] The fuel supply system 5 is connected to the engine inlet and return oil ports to form a fuel supply circuit. An oil consumption meter, a cooling system, a heating system, and a pressure regulating system are installed in the fuel supply system 5, and it can achieve instantaneous fuel consumption measurement, inlet oil temperature control, and inlet oil pressure control.

[0043] The low-voltage power supply and control system 6 is connected to components such as the engine controller, the transmission controller, and the engine starting motor, and is used to provide low-voltage power supply for the test power transmission system.

[0044] The exhaust system 7 is connected to the engine exhaust pipe, and is used to timely discharge the engine exhaust gas outdoors and adjust the engine exhaust back pressure.

[0045] The data acquisition system 8 is connected to the engine controller, the transmission controller, and various sensors in the power transmission system, and is used to collect the bus parameters of the power transmission system and the sensor parameters such as temperature, pressure, and flow rate. The transmission controller is used to control the water transmission case 17, the main transmission case 16, and the land transmission case 18.

[0046] The tracked amphibious vehicle realizes the driving action on land by driving the two active wheels on both sides through the power transmission system. It needs to use two relatively arranged dynamometers for loading. When on water, it drives the two water thrusters on both sides through the power transmission system to realize water travel. Since the power output direction of the thruster is perpendicular to the land power output direction, a bevel gearbox 3 is added during the water working condition test to convert the output shaft direction, so as to complete the water working condition and land working condition simulation tests respectively without changing the equipment installation state.

[0047] As Figure 1 shown, when conducting the water condition simulation test, the electric dynamometer 2 is connected to the output end of the bevel gearbox 3 through an elastic coupling and a torque and speed sensor, and the output end of the water transmission box 17 of the tested power transmission system is connected to the input end of the bevel gearbox 3 through an elastic coupling.

[0048] As Figure 2 shown, when conducting the land condition simulation test, the tested power transmission system is rotated 180°, and the electric dynamometer 2 is directly connected to the output end of the land transmission box 18 through an elastic coupling and a torque and speed sensor.

[0049] In addition, since the amphibious vehicle uses seawater as the cooling medium when driving on water, and when conducting the water condition simulation test, the seawater cooling condition is not available, a set of seawater simulation device is needed to cool the tested power transmission system. The seawater simulation device includes: a variable frequency water pump 9, a water storage tank 10, a flow meter 11, a water-water heat exchanger 12, a cooling circulating water system 13 and a temperature control valve 14.

[0050] The variable frequency water pump 9, the water storage tank 10, the flow meter 11, and the water-water heat exchanger 12 are connected in series with the seawater heat exchanger 19 of the tested piece through pipelines to form a closed circulating water path. After the variable frequency water pump 9 is started, taking the rated seawater flow rate of the cooling system of the tested piece as the target value and the flow rate value actually measured by the flow meter 11 as the feedback value, the variable frequency water pump 9 is adjusted using a PID controller, so as to realize the seawater flow simulation. The cooling circulating water system 13 is another open circulating water path. The cooling circulating water system 13 includes a cold water pump, a hot water pump, a cold water pool, a hot water pool and a cooling water tower, etc. This path of circulating water is connected to another channel of the water-water heat exchanger 12 through pipelines to realize heat exchange with the closed circulating water, for cooling the closed circulating water. At the same time, a temperature control valve 14 is installed at the inlet of the water-water heat exchanger 12, and a temperature sensor is installed at the inlet of the seawater heat exchanger 19. Taking the target seawater temperature as the control target value and the temperature measured at the inlet of the seawater heat exchanger 19 as the feedback value, the opening of the temperature control valve 14 is adjusted using a PID controller, so as to realize the control of the simulated seawater temperature.

[0051] Based on the above test platform structure, the steps of the power performance test method for the power transmission system in this embodiment are as follows:

[0052] If conducting the land condition test, the following operations are taken:

[0053] Step 1, first build the test platform and start each test equipment;

[0054] Step 101: Fix the power transmission system on the test bench through a connecting bracket or tooling, and supplement and check the oil and water levels of the engine and the transmission case;

[0055] Step 102: Connect the output end of the onshore transmission case 18, the torque and speed sensor, and the main shaft of the electric dynamometer 2 using an elastic coupling and perform alignment adjustment;

[0056] Step 103: Connect the inlet and return oil ports of the engine 15 to the fuel supply system 5;

[0057] Step 104: Connect the exhaust pipe of the engine 15 to the exhaust gas system 7;

[0058] Step 105: Connect the low-voltage power supply interface of the power transmission system controller and control interfaces such as the start signal and throttle signal of the engine 15 to the low-voltage power supply and control system 6;

[0059] Step 106: Connect the intake pipe of the engine 15 to the intake air conditioner 4;

[0060] Step 107: Arrange sensors for temperature, pressure, flow rate, pressure difference, etc. at the main measurement points of the power transmission system and connect them to the data acquisition system 8. At the same time, connect the bus signals of each controller of the power transmission system to the data acquisition system 8;

[0061] Step 108: Through the main control system 1 of the test bench, test whether the control functions of each system and the test piece are normal, check the connection status, functions, and communication of each system of the test bench, perform debugging on the start-stop control and throttle control of the engine 15, and confirm the rotation direction of the electric dynamometer 2 before the test.

[0062] Step Two: Start the engine and fully preheat the power transmission system;

[0063] Step Three: Set the target values of the intake air temperature and exhaust back pressure of the engine, and use the intake air conditioner 4 and the exhaust gas system 7 to automatically adjust the temperature and pressure;

[0064] Step Four: Switch the gears of the onshore transmission case 18 in the order of first forward gears and then reverse gears, and first low gears and then high gears;

[0065] Step Five: According to the maximum output speed and minimum output speed of the power transmission system corresponding to the current gear, take five to ten points at equal difference series for each intermediate speed point. The electric dynamometer 2 uses a constant speed mode to control the output speed of the power transmission system at the target speed point;

[0066] Step Six: Adjust the throttle opening to 100%;

[0067] Step Seven: When the power transmission system runs continuously for more than 30s and the output torque fluctuation range does not exceed ±3%, record data such as the total output torque of the power transmission system and the fuel consumption per hour;

[0068] Step 8: Switch the speed points and gears, repeat the above tests, and complete the acquisition of test data at all gears and various speeds.

[0069] Step 9: Calculate the effective power and fuel consumption rate at each speed point. Using the output speed of the power transmission system as the abscissa and the output torque as the ordinate, connect the data at each gear into a curve, and plot the curves of all gears on the same graph to form the output characteristic curve M = f(n) of the power transmission system.

[0070] If a water condition test is to be carried out, the following operations shall be taken:

[0071] Step 1: First, build the test platform and turn on each test equipment.

[0072] The specific building process is different from that of the land condition test in that:

[0073] Step 102: Use an elastic coupling to connect the output end of the water transmission box 17, the torque and speed sensor, the bevel gear box 3, and the main shaft of the electric dynamometer 2, and perform alignment adjustment.

[0074] Before step 108, a seawater simulation device needs to be built: Connect the variable frequency water pump 9, the water storage tank 10, the flowmeter 11, the water-water heat exchanger 12, and the seawater heat exchanger 19 in sequence with pipelines, and then connect the cooling circulating water system 13 to the water-water heat exchanger 12, and install a temperature control valve 14 in the pipeline.

[0075] Other steps are the same.

[0076] Step 2: Start the engine and fully preheat the power transmission system.

[0077] Step 3: Set the target values of the engine intake air temperature and exhaust back pressure, and use the intake air conditioner 4 and the exhaust system 7 to automatically adjust the temperature and pressure.

[0078] Step 4: Set the target values of the seawater simulation flow rate and temperature, and use the variable frequency water pump 9 and the temperature control valve 14 to automatically adjust the seawater simulation temperature and flow rate.

[0079] Step 5: Switch the gear of the water transmission box 17 to the forward gear. According to the maximum and minimum output speeds of the power transmission system under water conditions, take five to ten points at equal difference series at intermediate speed points. The electric dynamometer 2 uses the constant speed mode to control the output speed of the power transmission system at the target speed point.

[0080] Step 6: Adjust the throttle opening to 100%.

[0081] Step 7: After the power transmission system has been running continuously for more than 30 s and the output torque fluctuation range does not exceed ±3%, record data such as the total output torque of the power transmission system and the fuel consumption per hour.

[0082] Step 8: Switch the speed points and gears and repeat the above tests to complete the acquisition of test data at all gears and various speeds;

[0083] Step 9: Calculate the effective power and fuel consumption rate at each speed point. Taking the output speed of the power transmission system as the abscissa and the output torque as the ordinate, connect the data under each gear into a curve, and plot the curves of all gears on the same graph to form the output characteristic curve M = f(n) of the power transmission system.

[0084] This test platform can respectively complete the simulation tests of the water condition or the land condition according to the above test method steps. After the land condition test is completed, the power transmission system can also be directly rotated 180° and the bevel gearbox 3 can be added to convert the output shaft direction, so as to continue to complete the simulation test of the water condition without changing the installation state of the test platform equipment.

[0085] In summary, the above are only the preferred embodiments of the present invention and are not used to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A performance test platform for the power transmission system of a tracked amphibious vehicle, characterized in that, It includes a main control system of the test bench and a dynamometer, a bevel gearbox, an intake air conditioner, a fuel supply system, a low-voltage power supply and control system, an exhaust system, a data acquisition system, and a seawater simulation device connected to it through a bus; The intake air conditioner, the fuel supply system, the low-voltage power supply and control system, the exhaust system, and the data acquisition system are all connected to the engine of the test power transmission system and its auxiliary systems; when conducting onshore working condition simulation tests, two relatively arranged dynamometers are respectively connected to the power output ends of the onshore transmission boxes of the test power transmission system; when conducting offshore working condition simulation tests, two relatively arranged dynamometers are respectively connected to the power output ends of the offshore transmission boxes of the test power transmission system through the bevel gearbox. At the same time, the seawater simulation device cools the test power transmission system.

2. The performance test platform for the power transmission system of the tracked amphibious vehicle according to claim 1, characterized in that, The seawater simulation device includes a variable-frequency water pump, a water storage tank, a flow meter, a water-water heat exchanger, a cooling circulating water system, and a temperature control valve; The variable-frequency water pump, the water storage tank, the flow meter, and the water-water heat exchanger are connected in series through pipelines with the seawater heat exchanger of the test power transmission system to form a closed-loop circulating water path to achieve seawater flow simulation; the cooling circulating water system is connected to another channel of the water-water heat exchanger through pipelines to realize heat exchange with the closed-loop circulating water. At the same time, a temperature control valve is installed at the inlet of the water-water heat exchanger.

3. The performance test platform for the power transmission system of the tracked amphibious vehicle according to claim 2, characterized in that, After starting the variable-frequency water pump, taking the rated seawater flow of the cooling system of the test power transmission system as the target value and the flow value actually measured by the flow meter as the feedback value, use a PID controller to adjust the variable-frequency water pump, so as to achieve seawater flow simulation; A temperature sensor is installed at the inlet of the seawater heat exchanger. Taking the target seawater temperature as the control target value and the temperature measured at the inlet of the seawater heat exchanger as the feedback value, use a PID controller to adjust the opening of the temperature control valve, so as to achieve the control of the simulated seawater temperature.

4. A performance test method for the power transmission system of a tracked amphibious vehicle, characterized in that, Adopt the test platform as described in claim 1, and the test method includes the following steps: There is no sequence for onshore working condition tests and offshore working condition tests. If onshore working condition tests are carried out, the following operations are taken: Step 1, build the test platform and start each test equipment; Step 2, start the engine of the test power transmission system and fully preheat the power transmission system; Step 3, set the target values of the engine intake air temperature and exhaust back pressure, and use the intake air conditioner and the exhaust system to automatically adjust the temperature and pressure; Step 4, switch the gears of the onshore transmission box of the test power transmission system, and switch in the order of first forward gears and then reverse gears, and first low gears and then high gears; Step 5, according to the maximum output speed and minimum output speed of the power transmission system corresponding to the current gear, take five to ten points at equal difference series for each intermediate speed point. The dynamometer uses a constant speed mode to control the output speed of the power transmission system at the target speed point; Step 6, adjust the throttle opening to 100%; Step 7, when the test power transmission system runs continuously for more than 30 s and the output torque fluctuation range does not exceed ±3%, record the total output torque of the power transmission system and the fuel consumption per hour; Step 8, switch the speed points and gears and repeat the above tests to complete the acquisition of test data for all gears and various speeds; Step 9: Calculate the effective power and fuel consumption rate at each rotational speed point. Use the output rotational speed of the power transmission system as the abscissa and the output torque as the ordinate. Connect the data at each gear position into a curve, and plot the curves of all gear positions on the same graph to obtain the output characteristic curve of the tested power transmission system under onshore conditions; If an offshore condition test is to be carried out, the following operations shall be taken: Step 1: First, set up the test platform and turn on each test equipment; Step 2: Start the engine of the tested power transmission system and fully preheat the power transmission system; Step 3: Set the target values of the engine intake air temperature and exhaust back pressure, and automatically adjust the temperature and pressure using the intake air conditioner and exhaust smoke system; Step 4: Set the target values of the simulated seawater flow rate and temperature, and automatically adjust the simulated seawater temperature and flow rate using the seawater simulation device; Step 5: Switch the water transmission gearbox of the tested power transmission system to the forward gear. According to the maximum and minimum output rotational speeds of the power transmission system under offshore conditions, take five to ten points at equal arithmetic progression for the intermediate rotational speed points. The electric dynamometer uses the constant rotational speed mode to control the output rotational speed of the power transmission system at the target rotational speed points; Step 6: Adjust the throttle opening to 100%; Step 7: After the power transmission system has been running continuously for more than 30 s and the output torque fluctuation range does not exceed ±3%, record the total output torque of the power transmission system and the fuel consumption per hour; Step 8: Switch the rotational speed points and gear positions and repeat the above tests to complete the acquisition of test data at all gear positions and rotational speeds; Step 9: Calculate the effective power and fuel consumption rate at each rotational speed point. Use the output rotational speed of the power transmission system as the abscissa and the output torque as the ordinate. Connect the data at each gear position into a curve, and plot the curves of all gear positions on the same graph to obtain the output characteristic curve of the power transmission system of the tested power transmission system under offshore conditions.

5. The performance testing method of the power transmission system of the tracked amphibious vehicle according to claim 4, characterized in that When conducting an onshore condition test, the specific steps for setting up the test platform are as follows: Step 101: Fix the tested power transmission system on the test bench, replenish the oil and water of its engine and transmission box, and check the liquid levels; Step 102: Use an elastic coupling to connect the output end of the onshore transmission box, the torque rotational speed sensor, and the main shaft of the electric dynamometer and perform centering adjustment; Step 103: Connect the engine inlet and return oil ports to the fuel supply system; Step 104: Connect the engine exhaust pipe to the exhaust smoke system; Step 105: Connect the low-voltage power supply interface of the power transmission system controller and the control interfaces of the engine start signal and throttle signal to the low-voltage power supply and control system; Step 106: Connect the intake pipe of the engine to the intake air conditioner; Step 107: Arrange temperature, pressure, flow rate, and differential pressure sensors on the power transmission system and connect them to the data acquisition system. At the same time, connect the bus signals of each controller of the power transmission system to the data acquisition system; Step 108: Through the main control system of the test bench, test whether the control functions of each system and the tested power transmission system are normal, check the connection status, functions, and communication of each system of the test bench, conduct debugging of engine start-stop control and throttle control, and confirm the rotation direction of the electric dynamometer before the test.

6. The performance testing method for the power transmission system of a tracked amphibious vehicle according to claim 4 or 5, characterized in that If the onshore working condition test is carried out first and the offshore working condition test is carried out after the onshore working condition test is completed, when building the test platform, directly rotate the power transmission system by 180°. The two relatively arranged electric dynamometers are respectively connected to the power output ends of the waterborne transmission boxes of the power transmission system under test through bevel gearboxes, and a seawater simulation device is connected.

7. The performance testing method for the power transmission system of a tracked amphibious vehicle according to claim 6, characterized in that, The seawater simulation device includes a variable-frequency water pump, a water storage tank, a flowmeter, a water-water heat exchanger, a cooling circulating water system and a temperature control valve; the variable-frequency water pump, the water storage tank, the flowmeter and the water-water heat exchanger are connected in series through pipelines with the seawater heat exchanger of the power transmission system under test to form a closed-circuit circulating water to realize seawater flow simulation; the cooling circulating water system is connected to another channel of the water-water heat exchanger through a pipeline to realize heat exchange with the closed-circuit circulating water, and a temperature control valve is installed at the inlet of the water-water heat exchanger; After starting the variable-frequency water pump, taking the rated seawater flow of the cooling system of the power transmission system under test as the target value and the flow value actually measured by the flowmeter as the feedback value, use a PID controller to adjust the variable-frequency water pump, so as to realize seawater flow simulation; Install a temperature sensor at the inlet of the seawater heat exchanger, take the target seawater temperature as the control target value and the temperature measured at the inlet of the seawater heat exchanger as the feedback value, and use a PID controller to adjust the opening of the temperature control valve, so as to realize the control of the simulated seawater temperature.

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