A heat transfer test system and method for connecting rod under high speed and high power working condition

Abstract

The present application belongs to the technical field of heat transfer analysis test, and particularly relates to a heat transfer test system and method for a connecting rod under high-speed and high-power working conditions. The system comprises a test bench, a test single-cylinder assembly mechanism, a driving mechanism for driving the test single-cylinder assembly mechanism, a heating mechanism for heating the test single-cylinder assembly mechanism, a cooling mechanism for cooling the test single-cylinder assembly mechanism, a temperature measuring mechanism, and a control mechanism. The test single-cylinder assembly mechanism comprises a piston, a connecting rod, and a crankshaft. The temperature measuring mechanism comprises an infrared thermometer and a plurality of thermocouples distributed on the connecting rod. The control mechanism is connected with the driving mechanism, the heating mechanism, the cooling mechanism, and the temperature measuring mechanism, respectively, for performing speed control, heating control, cooling control, and temperature measurement reading collection, respectively. The method uses the system to measure the temperature field distribution and heat transfer law of the connecting rod in stages, provides a scientific basis for the reliability research of the engine connecting rod, and has a short cycle and good controllability.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of connecting rod heat transfer analysis test, and particularly relates to a heat transfer test system and method for connecting rod under high-speed and high-power working conditions. BACKGROUND

[0002] As one of the main parts of engines of vehicles, agricultural machinery, ships, aerospace, etc., the connecting rod is used to convert the reciprocating linear motion of the piston into the rotary motion of the crankshaft, and at the same time, the force acting on the piston is transmitted to the crankshaft to output power. The connecting rod is affected by thermal load and mechanical load, thermal stress and mechanical stress in the work, and thus is prone to functional failure, which greatly affects the normal work of the engine. For the connecting rod under high-speed and high-power working conditions, it is subjected to higher thermal load and alternating mechanical load, and thus the research on the heat transfer law of the connecting rod has a deeper practical significance under such a more severe coupled load.

[0003] At present, the researches at home and abroad mainly focus on the research directions of the structure design, lightweight and forming process of the connecting rod, and lack of the related research on the thermal-mechanical coupled stress and strain of the connecting rod in the working process. Therefore, it is necessary to design a test system and method for the heat transfer law research of the connecting rod part itself, so as to provide a scientific basis for the reliability research of the connecting rod. SUMMARY

[0004] The present application aims to provide a heat transfer test system for connecting rod under high-speed and high-power working conditions, so as to determine the heat transfer law of the connecting rod and provide a scientific basis for the reliability research of the connecting rod.

[0005] In order to achieve the above-mentioned purpose, the scheme of the present application is as follows: a heat transfer test system for connecting rod under high-speed and high-power working conditions, comprising a test bench, wherein the test bench is provided with a test single-cylinder assembly mechanism, a driving mechanism, a heating mechanism, a cooling mechanism, a temperature measuring mechanism and a control mechanism, the test single-cylinder assembly mechanism comprises a cylinder liner, a piston, a connecting rod and a crankshaft, the driving mechanism is used to drive the crankshaft, the heating mechanism comprises an infrared temperature measuring instrument and a heating assembly used for heating the test single-cylinder assembly mechanism, the cooling mechanism is used to cool the test single-cylinder assembly mechanism, the temperature measuring mechanism comprises a data acquisition recorder and a plurality of thermocouples, the plurality of thermocouples are distributed on the connecting rod along the length direction of the connecting rod, and the plurality of thermocouples are connected with the data acquisition recorder through lead wires; the control mechanism is connected with the driving mechanism, the heating mechanism, the cooling mechanism and the temperature measuring mechanism respectively, and is used to perform speed control, heating control and temperature reading acquisition respectively.

[0006] The present application also provides a heat transfer test method for connecting rod under high-speed and high-power working conditions, which measures the heat transfer law function image of the connecting rod by using the above-mentioned heat transfer test system, and comprises the following steps:

[0007] S1. Set crankshaft speed: Set the crankshaft speed to 2000-4000 rpm via the control mechanism;

[0008] S2. Phased Testing: The entire test is divided into four phases, including Phase 1, Phase 2, Phase 3, and Phase 4. In Phase 1 / 2 / 3, the control mechanism is set to shut down the laser when the infrared thermometer detects that the piston temperature is at the end of the intake stroke / compression stroke / power stroke peak temperature. The intake stroke end temperature is 600–650K, the compression stroke end temperature is 1000–1050K, and the power stroke peak temperature is 1800–2200K. In Phase 4, the control mechanism is set to shut down the cooling mechanism when the infrared thermometer detects that the piston temperature is at the end of the exhaust stroke. The exhaust stroke end temperature is 900–950K.

[0009] In the first, second, and third test phases, the heat transfer test system operates. The drive mechanism drives the crankshaft to rotate, and the heating mechanism heats the piston to the intake stroke end temperature, compression stroke end temperature, and peak power temperature. Thermocouples transmit temperature signals to a data acquisition and recording device, which in turn transmits the signals to a control mechanism. The control mechanism analyzes and processes the data to obtain a heat transfer function image of the connecting rod at the intake stroke end temperature, compression stroke end temperature, and peak power temperature. After the third test phase, the cooling mechanism is activated to cool the cylinder liner, reducing the piston temperature to the exhaust stroke end temperature. Thermocouples transmit temperature signals to a data acquisition and recording device, which in turn transmits the signals to a control mechanism. The control mechanism analyzes and processes the data to obtain a heat transfer function image of the connecting rod at the exhaust stroke end temperature.

[0010] S3. Reset the crankshaft speed and repeat step S2 or shut down the system to end the test.

[0011] The working principle and beneficial effects of this scheme are as follows: 1) In this scheme, the heat transfer test method for the connecting rod relies on a heat transfer test system. A drive mechanism drives the crankshaft to rotate, simulating the speed and power changes of the connecting rod during engine operation. A heating mechanism heats the piston, simulating the temperature field changes of the connecting rod during engine operation. A temperature measuring mechanism measures the real-time temperature at a pre-set position of the connecting rod (where the thermocouple is located). The temperature field distribution and heat transfer law of the connecting rod are obtained through analysis and processing by a control mechanism, providing a scientific basis for the reliability study of engine connecting rod operation. Specifically, the heat transfer test method divides the entire test process into four stages, thereby obtaining the heat transfer laws of the connecting rod at the end temperature of the intake stroke, the end temperature of the compression stroke, the peak temperature of the power stroke, and the end temperature of the exhaust stroke.

[0012] 2) The heat transfer test method in this scheme has the advantages of short test cycle, high reliability and good controllability.

[0013] 3) This method can measure the heat transfer characteristics of the connecting rod in both static and dynamic states.

[0014] Optionally, the temperature measuring mechanism further includes a lead wire constraint assembly, which includes an outer ring, an inner ring, and a wire harness for binding the lead wire. The outer ring is mounted on the test bench via a support rod, and the inner ring is suspended inside the outer ring by a suspension rope.

[0015] In this design, the lead wire passes through the inner ring and connects to the data acquisition and recording device. The lead wire is then secured with cable ties located on both sides of the inner ring, thus confining the lead wire within the ring. In this way, during the linkage's movement, the lead wire moves with the linkage, and the inner ring can swing within the outer ring, adapting to the lead wire's movement and preventing uncontrolled movement that could affect the experiment.

[0016] Optionally, the suspension rope is an elastic rope.

[0017] In this design, the elastic cord is elastic, and the inner ring can move a greater distance, avoiding rigid tension on the lead wire and thus preventing the lead wire from breaking.

[0018] Optionally, the test bench is further provided with a fixing assembly for fixing the cylinder liner. The fixing assembly includes a fixing rod and a fixing ring. One end of the fixing rod is fixedly installed on the test bench, and the other end of the fixing rod is fixedly connected to the fixing ring. A rubber ring is fixedly connected to the inner circumferential wall of the fixing ring, and the inner diameter of the rubber ring is smaller than the outer diameter of the cylinder liner.

[0019] In this design, the cylinder liner is inserted into the retaining ring, and the rubber ring abuts against the outer peripheral wall of the cylinder liner, thereby fixing the cylinder liner in the retaining ring so that the piston can slide vertically back and forth inside the cylinder liner.

[0020] Optionally, a horizontally arranged clamping screw is threaded onto the retaining ring, and the end of the clamping screw near the cylinder liner can clamp against the cylinder liner.

[0021] In this design, the tightening screw tightens the cylinder liner, which further ensures that the cylinder liner is stably fixed inside the retaining ring.

[0022] Optionally, the drive mechanism includes a drive motor, the output end of which is fixedly connected to the end of the crankshaft, and the drive motor is controlled by the control mechanism.

[0023] In this design, a drive motor drives the crankshaft to rotate. Since the big end of the connecting rod is rotatably connected to the crankshaft, and the small end is rotatably connected to the piston via a piston pin, the crankshaft rotation, through the transmission of the connecting rod, drives the piston to reciprocate linearly within the cylinder liner, thus realizing the operation of the experimental single-cylinder assembly mechanism. Furthermore, the drive motor can adjust the crankshaft speed according to commands issued by the control mechanism, thereby determining the heat transfer characteristics of the connecting rod at different speeds.

[0024] Optionally, the heating assembly includes a laser and a beam shaper. Both the laser and the infrared thermometer are connected to the control mechanism. The control mechanism controls the laser to work according to the signal transmitted by the infrared thermometer. The laser emitted by the laser passes through the beam shaper and then vertically irradiates the upper surface of the piston.

[0025] In this scheme, the heating mechanism uses laser heating to heat the piston. Laser heating has the advantages of single-directional light source and excellent controllability, enabling concentrated heating of the piston and reducing the thermal impact on the drive mechanism, cooling mechanism, and control mechanism. Furthermore, the heat source of laser heating is presented in the form of a laser spot, which can be controlled to a very small or uniform size through the optical path. Since the laser spot size and heating time can be precisely controlled, the heating temperature and heating time can be precisely controlled by adjusting the laser power under the control of the control mechanism, thereby enabling the determination of the heat transfer characteristics of the connecting rod at different temperatures.

[0026] Optionally, the cooling mechanism includes a refrigeration compressor and an air-cooled nozzle connected to the refrigeration compressor via a pipe. The refrigeration compressor is controlled by the control mechanism, and the air-cooled nozzle is positioned toward the cylinder liner.

[0027] In this design, the cooling mechanism uses air cooling to cool the cylinder liner, piston, and connecting rod, avoiding contact between the cooling mechanism and the test single-cylinder assembly mechanism.

[0028] Optionally, the test bench is also equipped with an oil pan for collecting lubricating oil. In this design, the oil pan is used to collect and store the lubricating oil flowing down from the friction surfaces of the test cylinder assembly mechanism during the test. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of a heat transfer test system for a connecting rod under high-speed and high-power conditions according to Embodiment 1 of the present invention.

[0030] Figure 2 for Figure 1 Enlarged diagram of A in the middle;

[0031] Figure 3 for Figure 1 Right view of the middle connecting rod;

[0032] Figure 4 This is a schematic diagram of a heat transfer test system for connecting rods under high-speed and high-power conditions, according to Embodiment 2 of the present invention. Detailed Implementation

[0033] The following detailed description illustrates the specific implementation method:

[0034] The markings in the accompanying drawings of the instruction manual include: test bench 1, cylinder liner 2, piston 3, connecting rod 4, connecting rod small end 401, connecting rod big end 402, crankshaft 5, connecting rod neck 501, fixing plate 6, fixing rod 7, fixing ring 8, rubber ring 9, clamping screw 10, drive motor 11, infrared thermometer 12, laser 13, beam shaper 14, fixing auxiliary rod 15, refrigeration compressor 16, through pipe 17, air-cooled nozzle 18, data acquisition recorder 19, thermocouple 20, lead wire 21, outer ring 22, inner ring 23, cable tie 24, support rod 25, suspension rope 26, mounting bracket 27, PC 28, oil pan 29.

[0035] Example One

[0036] This embodiment provides a heat transfer testing system for connecting rods under high-speed, high-power operating conditions, such as... Figure 1 , Figure 2 and Figure 3 As shown: The test bench 1 includes a test single-cylinder assembly mechanism, a drive mechanism, a heating mechanism, a cooling mechanism, a temperature measuring mechanism, and a control mechanism. The test single-cylinder assembly mechanism includes a cylinder liner 2, a piston 3, a connecting rod 4, and a crankshaft 5. The piston 3 is vertically slidably connected inside the cylinder liner 2, which has no top cover. The small end 401 of the connecting rod is rotatably connected to the piston 3 via a pin, and the large end 402 of the connecting rod is rotatably connected to the connecting rod neck 501 of the crankshaft 5. A fixing plate 6 is bolted to the test bench 1, and the right end of the crankshaft 5 is rotatably connected to the fixing plate 6 via a bearing, thus supporting the right end of the crankshaft 5. Additionally, combined with... Figure 2As shown, the test bench 1 is equipped with a fixing assembly for fixing the cylinder liner 2. The fixing assembly includes a fixing rod 7 and a fixing ring 8. The bottom end of the fixing rod 7 is bolted to the test bench 1, and the top end of the fixing rod 7 is welded to the fixing ring 8. A rubber ring 9 is bonded to the inner circumferential wall of the fixing ring 8. The inner diameter of the rubber ring 9 is smaller than the outer diameter of the cylinder liner 2. A horizontally arranged clamping screw 10 is threaded onto the fixing ring 8, and the left end of the clamping screw 10 can clamp against the cylinder liner 2.

[0037] The drive mechanism includes a drive motor 11, the output end of which is fixedly connected to the left end of the crankshaft 5. The heating mechanism uses infrared heating or laser heating to heat the test bar assembly mechanism. In this embodiment, laser heating is used. Specifically, the heating mechanism includes an infrared thermometer 12 and a heating assembly. The heating assembly includes a laser 13 and a beam shaper 14. The laser emitted by the laser 13 passes through the beam shaper 14 and then vertically irradiates the upper surface of the piston 3. Additionally, a fixed auxiliary rod 15 is welded to the fixed rod 7, and both the infrared thermometer 12 and the laser 13 are connected to the fixed auxiliary rod 15.

[0038] The cooling mechanism uses air cooling, water cooling, or a combination of both to cool the test single bar assembly mechanism. In this embodiment, the cooling mechanism uses air cooling to cool the test single bar assembly mechanism. Specifically, the cooling mechanism includes a refrigeration compressor 16 and an air-cooled nozzle 18 connected to the refrigeration compressor 16 through a pipe 17. The air-cooled nozzle 18 is positioned towards the cylinder liner 2 and is used to spray the cold air generated by the refrigeration compressor 16 onto the cylinder liner 2.

[0039] Combination Figure 3 As shown, the temperature measuring mechanism includes a data acquisition and recording device 19 and several thermocouples 20. The thermocouples 20 are evenly distributed along the length of the connecting rod 4. Specifically, the thermocouples 20 are welded to the connecting rod 4, and the thermocouples 20 are wrapped with glass fiber or coated with insulating paint to protect the thermocouple wires. In this embodiment, there are five thermocouples 20. In addition, the thermocouples 20 are connected to the data acquisition and recording device 19 via leads 21. The temperature measuring mechanism also includes a lead wire 21 constraint assembly, which includes an outer ring 22, an inner ring 23, and several binding straps 24 for binding the leads 21. The outer ring 22 is fixedly installed on the test bench 1 by a support rod 25, and the inner ring 23 is suspended inside the outer ring 22 by a suspension rope 26, which is an elastic rope. In this embodiment, two cable ties 24 are used. After the two cable ties 24 are used to bundle the lead wire 21, they are located on both sides of the inner ring 23, thereby preventing the lead wire 21 from moving excessively relative to the inner ring 23. In addition, the refrigeration compressor 16 and the data acquisition recorder 19 are both mounted on the test bench 1 via mounting brackets 27.

[0040] The control mechanism is a PC 28, which is connected to the drive mechanism, heating mechanism, cooling mechanism, and temperature measuring mechanism to perform speed control, heating control, cooling control, and temperature reading acquisition, respectively. Specifically, the drive motor 11, infrared thermometer 12, laser 13, refrigeration compressor 16, and data acquisition recorder 19 are all connected to the PC 28. Thus, the drive motor 11, laser 13, and refrigeration compressor 16 are all controlled by the PC 28. Furthermore, the temperature signal measured by the infrared thermometer 12 is transmitted to the PC 28, and the PC 28 controls the laser 13 to operate based on the temperature signal transmitted by the infrared thermometer 12. Additionally, the temperature signal measured by the thermocouple 20 is transmitted to the PC 28 via the data acquisition recorder 19, where the PC 28 analyzes and processes the signal to generate a heat transfer function graph of the connecting rod 4.

[0041] This embodiment also provides a heat transfer test method for connecting rods under high-speed and high-power conditions. This heat transfer test method uses the aforementioned heat transfer test system for connecting rod 4 under high-speed and high-power conditions to measure the heat transfer law function image of connecting rod 4, and specifically includes the following steps:

[0042] Step 1: Set the crankshaft 5 speed: Set the speed of the drive motor 11 on the PC 28, thereby setting the crankshaft 5 speed to 2000 rpm.

[0043] Step 2: Phased Testing: The entire test is divided into four phases, including Phase 1, Phase 2, Phase 3, and Phase 4.

[0044] In the first phase of the experiment, the PC 28 was set to shut off the laser 13 when the infrared thermometer 12 detected that the piston 3 temperature reached the end temperature of the intake stroke (600K). The heat transfer test system was running, and the crankshaft 5 rotated under the drive of the drive motor 11 (crankshaft 5 speed 2000rpm). The PC 28 controlled the laser 13 to turn on, heating the piston 3, and the piston 3's temperature gradually increased. During this process, the infrared thermometer 12 monitored the temperature of the piston 3's upper surface in real time. When the infrared thermometer 12 detected that the temperature of the piston 3's upper surface had risen to 600K, the PC 28 controlled the laser 13 to turn off, stopping the heating of the piston 3. For the next 5 minutes, the infrared thermometer 12 continued to monitor the temperature of the piston 3's upper surface, and the PC 28 controlled the laser 13 to maintain the temperature of the piston 3's upper surface at 600K. In the first stage of the experiment, thermocouple 20 detected the temperature at various points on the connecting rod 4 and transmitted the temperature signal to the data acquisition and recording instrument 19. The data acquisition and recording instrument 19 then transmitted the signal to the PC 28. After analysis and processing, a heat transfer function image of the connecting rod 4 at the end temperature of the intake stroke was generated and displayed on the screen of the PC 28.

[0045] In the second phase of the experiment, the PC 28 was set to turn off the laser 13 when the infrared thermometer 12 detected that the piston 3 temperature was at the end of the compression stroke (1000K). The heat transfer test system continued to run, and the PC 28 controlled the laser 13 to turn on, heating the piston 3, causing its temperature to gradually rise. When the infrared thermometer 12 detected that the temperature of the upper surface of the piston 3 had risen to 1000K, the PC 28 controlled the laser 13 to turn off, stopping the heating of the piston 3. For the next 5 minutes, the infrared thermometer 12 continued to monitor the temperature of the upper surface of the piston 3, and the PC 28 controlled the laser 13 to maintain the temperature of the upper surface of the piston 3 at 1000K. In the second stage of the experiment, thermocouple 20 detects the temperature at various points on the connecting rod 4 and transmits the temperature signal to the data acquisition recorder 19. The data acquisition recorder 19 then transmits the signal to the PC 28. After analysis and processing, a heat transfer function image of the connecting rod 4 at the end temperature of the compression stroke is generated and displayed on the screen of the PC 28.

[0046] In the third stage of the experiment, PC 28 was set to turn off laser 13 when the infrared thermometer 12 detected that the temperature of piston 3 reached the peak temperature of the power stroke (1800K). The heat transfer test system continued to run, and PC 28 controlled laser 13 to turn on, heating piston 3, and the temperature of piston 3 gradually increased. When the infrared thermometer 12 detected that the temperature of the upper surface of piston 3 had risen to 1800K, PC 28 controlled laser 13 to turn off, stopping the heating of piston 3. For the next 5 minutes, infrared thermometer 12 continued to monitor the temperature of the upper surface of piston 3, and PC 28 controlled the turning of laser 13 to maintain the temperature of the upper surface of piston 3 at 1800K. In the third stage of the experiment, thermocouple 20 detects the temperature at various points on the connecting rod 4 and transmits the temperature signal to the data acquisition recorder 19. The data acquisition recorder 19 then transmits the signal to the PC 28, which analyzes and processes it to generate a heat transfer function image of the connecting rod 4 at the peak temperature of the power stroke. This image is then displayed on the screen of the PC 28.

[0047] In the fourth stage of the experiment, the PC 28 was set to shut down the laser 13 when the infrared thermometer 12 detected that the piston 3 temperature was at the end of the exhaust stroke, with the exhaust stroke end temperature being 900K. After the third stage of the experiment, the PC 28 controlled the refrigeration compressor 16 to start, and cold air was sprayed onto the cylinder liner 2 through the air-cooling nozzle 18, thereby cooling the cylinder liner 2 and piston 3. When the infrared thermometer 12 detected that the temperature of the upper surface of piston 3 had dropped to 900K, the PC 28 controlled the refrigeration compressor 16 to shut down, stopping the cooling of piston 3. For the next 5 minutes, the infrared thermometer 12 continued to monitor the temperature of the upper surface of piston 3, and the PC 28 controlled the laser 13 to keep the temperature of the upper surface of piston 3 at 900K. In the fourth stage of the experiment, thermocouple 20 detects the temperature at various points on connecting rod 4 and transmits the temperature signal to data acquisition recorder 19. Data acquisition recorder 19 then transmits the signal to PC 28. After analysis and processing, a heat transfer function image of connecting rod 4 at the end temperature of the exhaust stroke is generated and displayed on the screen of PC 28.

[0048] After the third and fourth stages of the test, PC 28 controls the refrigeration compressor 16 to work for 10 minutes, thereby cooling the cylinder liner 2 and piston 3 for 10 minutes. After 10 minutes, the system is shut down to end the test; or, after 10 minutes, the crankshaft 5 speed is reset to 2500 rpm on PC 28, and step two is repeated to obtain the heat transfer function graphs of connecting rod 4 at the end of the intake stroke, the end of the compression stroke, the peak temperature of the power stroke, and the end of the exhaust stroke under the condition that the crankshaft 5 speed is 2500 rpm.

[0049] In addition, during the operation of the heat transfer test system, the lead wire 21 is bundled by the wire harness 24 and is constrained within the inner ring 23. Therefore, during the combined vertical and horizontal movement of the connecting rod 4, the lead wire 21 is concentratedly constrained within the inner ring 23. The inner ring 23 sways relative to the outer ring 22, thereby adapting to the movement of the connecting rod 4, preventing the lead wire 21 from swaying randomly and affecting the test, and also preventing the lead wire 21 from being excessively stretched.

[0050] In summary, this embodiment allows for the adjustment of the crankshaft 5 speed to simulate the speed and power changes of the connecting rod 4 during engine operation, and also allows for the adjustment of the temperature of the piston 3's upper surface to simulate the temperature field changes of the connecting rod 4 during engine operation. This, in turn, simulates the actual high-speed, high-power operating conditions of the connecting rod 4, and allows for the measurement of heat transfer function images of the connecting rod 4 at different speeds, temperatures, and operating durations, providing a scientific basis for the study of engine connecting rod reliability. Furthermore, this embodiment divides the experimental process into four stages, corresponding to the engine's intake stroke, compression stroke, power stroke, and exhaust stroke, respectively, thereby measuring the heat transfer function images of the connecting rod 4 at the end temperatures of the intake stroke, compression stroke, power stroke peak temperatures, and exhaust stroke.

[0051] Example Two

[0052] The difference between this embodiment and Embodiment 1 is that: Figure 4 As shown, in this embodiment, the test single-cylinder assembly mechanism also includes an oil pan 29, which is located below the connecting rod 4 and is used to collect and store the lubricating oil flowing down the friction surfaces of the test single-cylinder assembly mechanism during the test.

[0053] The above are merely embodiments of the present invention. The invention is not limited to the fields covered by these embodiments. Commonly known structures and characteristics are not described in detail here. Those skilled in the art are aware of all common technical knowledge in the field prior to the application date or priority date, are aware of all existing technologies in that field, and have the ability to apply conventional experimental methods prior to that date. Those skilled in the art can improve and implement this solution based on the guidance provided in this application and their own capabilities. Some typical known structures or methods should not be obstacles for those skilled in the art to implement this application. It should be noted that those skilled in the art can make several modifications and improvements without departing from the structure of the present invention. These should also be considered within the scope of protection of the present invention, and will not affect the effectiveness or practicality of the invention. The scope of protection claimed in this application should be determined by the content of its claims. The specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A heat transfer test method for connecting rods under high-speed and high-power operating conditions, characterized in that: A heat transfer testing system for connecting rods under high-speed, high-power operating conditions is disclosed. The system includes a test bench, on which are mounted a single-cylinder assembly mechanism, a drive mechanism, a heating mechanism, a cooling mechanism, a temperature measuring mechanism, and a control mechanism. The single-cylinder assembly mechanism includes a cylinder liner, a piston, a connecting rod, and a crankshaft. The drive mechanism drives the crankshaft. The heating mechanism includes an infrared thermometer and a heating assembly for heating the single-cylinder assembly mechanism. The cooling mechanism cools the single-cylinder assembly mechanism. The temperature measuring mechanism includes a data acquisition and recording device and several thermocouples distributed along the length of the connecting rod. Each thermocouple is connected to the data acquisition and recording device via leads. The control mechanism is connected to the drive mechanism, heating mechanism, cooling mechanism, and temperature measuring mechanism respectively, and is used to perform speed control, heating control, and temperature reading acquisition. The test method includes the following steps: S1. Set crankshaft speed: Set the crankshaft speed to 2000-4000 rpm via the control mechanism; S2. Phased Testing: The entire test is divided into four phases, including Phase 1, Phase 2, Phase 3, and Phase 4, corresponding to the engine's intake stroke, compression stroke, power stroke, and exhaust stroke, respectively. In Phase 1, Phase 2, or Phase 3, the control mechanism is set to shut off the laser when the infrared thermometer detects that the piston temperature is at the end of the intake stroke, the end of the compression stroke, or the peak temperature of the power stroke. The end temperature of the intake stroke is 600–650K, the end temperature of the compression stroke is 1000–1050K, and the peak temperature of the power stroke is 1800–2200K. In Phase 4, the control mechanism is set to shut off the cooling mechanism when the infrared thermometer detects that the piston temperature is at the end of the exhaust stroke. The end temperature of the exhaust stroke is 900–950K. In the first, second, or third stage of the test, the heat transfer test system operates, the drive mechanism drives the crankshaft to rotate, and the heating mechanism heats the piston to the end temperature of the intake stroke, the end temperature of the compression stroke, or the peak temperature of the power stroke. Thermocouples transmit temperature signals to a data acquisition and recording instrument, which in turn transmits the temperature signals to a control mechanism. After analysis and processing, the control mechanism obtains a heat transfer function image of the connecting rod at the end temperature of the intake stroke, the end temperature of the compression stroke, or the peak temperature of the power stroke. After the third stage of the test, the cooling mechanism is activated to cool the cylinder liner, reducing the piston temperature to the end temperature of the exhaust stroke. Thermocouples transmit temperature signals to a data acquisition and recording instrument, which in turn transmits the temperature signals to a control mechanism. After analysis and processing, the control mechanism obtains a heat transfer function image of the connecting rod at the end temperature of the exhaust stroke. S3. Reset the crankshaft speed and repeat step S2 or shut down the system to end the test.

2. The heat transfer test method for connecting rods under high-speed and high-power conditions according to claim 1, characterized in that: The temperature measuring mechanism also includes a lead wire constraint assembly, which includes an outer ring, an inner ring, and a wire harness for binding the lead wire. The outer ring is mounted on the test bench via a support rod, and the inner ring is suspended inside the outer ring by a suspension rope.

3. The heat transfer test method for connecting rods under high-speed and high-power conditions according to claim 2, characterized in that: The suspension rope is an elastic rope.

4. The heat transfer test method for connecting rods under high-speed and high-power conditions according to claim 1, characterized in that: The test bench is also equipped with a fixing assembly for fixing the cylinder liner. The fixing assembly includes a fixing rod and a fixing ring. One end of the fixing rod is fixedly installed on the test bench, and the other end of the fixing rod is fixedly connected to the fixing ring. A rubber ring is fixedly connected to the inner circumferential wall of the fixing ring. The inner diameter of the rubber ring is smaller than the outer diameter of the cylinder liner.

5. The heat transfer test method for connecting rods under high-speed and high-power conditions according to claim 4, characterized in that: The fixed ring is threaded with a horizontally arranged clamping screw, and the end of the clamping screw near the cylinder liner can clamp against the cylinder liner.

6. The heat transfer test method for connecting rods under high-speed and high-power conditions according to claim 1, characterized in that: The drive mechanism includes a drive motor, the output end of which is fixedly connected to the end of the crankshaft, and the drive motor is controlled by the control mechanism.

7. The heat transfer test method for connecting rods under high-speed and high-power conditions according to claim 1, characterized in that: The heating assembly includes a laser and a beam shaper. Both the laser and the infrared thermometer are connected to the control mechanism. The control mechanism controls the laser to work according to the signal transmitted by the infrared thermometer. The laser emitted by the laser passes through the beam shaper and then vertically irradiates the upper surface of the piston.

8. The heat transfer test method for connecting rods under high-speed and high-power conditions according to claim 1, characterized in that: The cooling mechanism includes a refrigeration compressor and an air-cooled nozzle connected to the refrigeration compressor via a pipe. The refrigeration compressor is controlled by the control mechanism, and the air-cooled nozzle is positioned towards the cylinder liner.

9. The heat transfer test method for connecting rods under high-speed and high-power conditions according to claim 1, characterized in that: The test bench is also equipped with an oil pan for collecting lubricating oil.

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