Internal cooling oil cavity piston oscillation cooling test device

Abstract

The invention discloses an oscillation cooling test device for an inner cooling oil cavity piston. The oscillation cooling test device comprises a test piston, a platform, a machine body, a modular cylinder sleeve tool, a movement mechanism, a hot air flow guide tool, a constant-temperature and constant-pressure engine oil supply system, a thermocouple and a double-connecting-rod temperature measurement lead mechanism. The machine body is fixed on the platform; the modularized cylinder sleeve tool is fixed on the machine body; the test piston and the modular cylinder sleeve tool form a translational motion pair; the motion mechanism drives the test piston to reciprocate up and down in the modular cylinder sleeve tool; the hot air guide tool guides hot air to heat the firepower surface of the test piston; the oil supply system provides controllable constant-temperature and constant-pressure engine oil for the test piston; a measuring point of the thermocouple is fixed on a corresponding measuring point of the test piston, the thermocouple is fixed by the double-connecting-rod temperature measuring lead mechanism, and a signal point of the thermocouple penetrates through the modularized cylinder sleeve tool to be connected with an external signal acquisition device, so that real-time measurement and acquisition of a temperature signal of the measuring point of the test piston are realized.

Description

Technical Field

[0001] This invention relates to the field of internal combustion engine testing technology, specifically to a piston oscillation cooling test device with an internal cooling oil chamber. Background Technology

[0002] In recent years, the power of diesel engines has been continuously increasing, and the thermal load on their components has also increased accordingly. The piston is a crucial component of a diesel engine; over 50% of the energy transferred from the high-temperature combustion gases inside the cylinder to the combustion chamber components is transferred to the piston. Excessive thermal load on the piston can lead to piston deformation, and even cracks or burn-out of the piston crown. Furthermore, excessive thermal deformation can damage the fit between the piston and cylinder liner, accelerating wear and resulting in reduced diesel engine power, or even cylinder scoring or seizure.

[0003] There are two common piston cooling methods: one is to increase the thermal resistance of the piston top surface by using a heat-insulating coating; the other is to increase the heat transfer of the piston by using enhanced bottom oil spray cooling. Because the bonding force between the surface heat-insulating coating and the piston is weak and it can lead to significant internal stress, oil spray cooling is currently the most widely used piston cooling method. It mainly includes two types: internal cavity oil spray cooling and internal cooling oil cavity oscillation cooling. Internal cavity oil spray cooling does not require changing the piston structure, but it only improves the cooling effect at and near the oil jet landing point within the piston cavity, and the amount of heat carried away by the oil is limited. Internal cooling oil cavity oscillation cooling is a cooling method adopted for pistons with a new internal cooling oil cavity structure. In an internal cooling oil cavity piston, an annular oil cavity is machined below the piston's firing face, and two oil passages are opened in the oil cavity to connect it to the lower surface of the piston. Oil can enter the oil cavity through the oil passages, oscillate and exchange heat within the oil cavity, and then flow back out of the oil cavity, effectively carrying away the heat from the piston. This is currently the most effective piston cooling method.

[0004] Because the piston operates within the cylinder liner of an internal combustion engine, its thermodynamic state and oil heat transfer characteristics are difficult to monitor directly in real time. Typically, a dedicated test bench and an external temperature sensing system are required to transmit signals externally in order to conduct oscillatory cooling tests on the piston's internal cooling oil chamber. Current research on oscillatory cooling methods for internal cooling oil chamber pistons by scholars both domestically and internationally faces the following limitations: First, existing research generally uses independent internal cooling oil chamber models, while in real-world piston operating conditions, the inertial load increases significantly, the heating and cooling process exhibits multi-physics coupling characteristics, and real-time temperature measurement is difficult due to the limitations of the sealed cavity structure. This results in a lack of research data on oscillatory cooling tests for real-scale pistons. Second, due to the diverse piston diameters of high-speed diesel engines, the utilization rate of dedicated test benches developed for single-size pistons is insufficient, significantly increasing testing costs. These technical bottlenecks make it difficult to accurately analyze the dynamic influence of oil jet parameters on piston cooling efficiency under actual internal combustion engine operating conditions. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the technical problem this invention aims to solve is to provide an internal cooling oil chamber piston oscillation cooling test device.

[0006] The technical solution of the present invention to solve the aforementioned technical problem is to provide an internal cooling oil chamber piston oscillation cooling test device, characterized in that the device includes a test piston, a platform, a body, a modular cylinder liner tooling, a motion mechanism, a hot air guiding tooling, a constant temperature and pressure oil supply system, a thermocouple, and a double-linkage temperature measuring lead mechanism. The machine body is fixed on the platform; the modular cylinder liner fixture is fixed on the machine body; the test piston is installed inside the modular cylinder liner fixture, forming a translational motion pair with the modular cylinder liner fixture; the motion mechanism drives the test piston to reciprocate up and down inside the modular cylinder liner fixture; the hot air guiding fixture is fixed on the modular cylinder liner fixture, guiding hot air to heat the firing surface of the test piston; the oil supply system provides controllable constant temperature and pressure oil to the test piston to simulate the cooling conditions in the piston cooling test, and at the same time provides lubrication and cooling to the motion mechanism located below the test piston; the thermocouple measuring points are fixed on the corresponding measuring points of the test piston, and the double-link temperature measuring lead mechanism fixes the thermocouples. The signal points of the thermocouples pass through the modular cylinder liner fixture and connect to an external signal acquisition device, converting the electrical signal into a temperature signal, realizing the real-time measurement and acquisition of the temperature signal of the measuring points of the test piston.

[0007] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) This invention addresses the characteristic of the internally cooled oil chamber piston using an oscillating cooling method. It simulates the piston's movement within the cylinder liner through a motion mechanism, and uses a hot air guiding fixture and oil supply system to simulate the piston's hot and cold boundaries under actual working conditions. Thermocouple temperature measurement combined with a double-linkage temperature measuring lead mechanism transmits the piston temperature signal during the test to the outside in real time, realizing the real-time measurement of the temperature of the internally cooled oil chamber piston using an oscillating cooling method. Based on this, it can realize the measurement of the real-time temperature and evaluation of the heat transfer characteristics of the internally cooled oil chamber piston using an oscillating cooling method under different motor speeds, different high-temperature air heating temperatures and heating powers, different oil supply pressures, different oil supply flow rates, different oil supply temperatures, and different injection pipe diameters. It has good versatility for oscillating cooling heat transfer characteristic tests on pistons of different diameters, thereby guiding the development of internally cooled oil chamber pistons and the design and improvement of internally cooled oil chamber structures, as well as determining the optimal oil supply parameters for diesel engine cooling systems. This test device has good versatility, operability, reliability, and low test cost.

[0008] (2) The present invention adopts a modular cylinder liner tooling including an intermediate body, an outer cylinder liner, an inner cylinder liner, a connecting rod, and an oil injection block and an oil injection pipe in the oil supply system. The mechanical interface dimensions of these parts are fixed. According to the diameter of the test piston, the above parts can be quickly parametrically designed and can be easily replaced and installed. The oscillation cooling heat transfer characteristics test of pistons in the diameter range of 110~160mm can be achieved at a lower cost.

[0009] (3) The present invention uses a thermocouple as a piston temperature sensor, which has the advantages of real-time, small error and less damage to piston structure compared with the traditional hardness plug temperature measurement method. The double-link temperature lead wire mechanism is used to lead the thermocouple out of the test device, which effectively solves the problem of entanglement and breakage that may occur when the thermocouple moves rapidly back and forth with the test piston, and ensures the reliability of temperature data measurement.

[0010] (4) The present invention uses a variable frequency motor to drive the test piston to reciprocate, which can simulate the real motion law of the diesel engine piston. By adjusting the speed of the motor, the motion of the piston at different speeds of the diesel engine can be simulated. The air intake pipe of the hot air guide tool can be connected to an air heater with adjustable flow and temperature on the market, so as to use hot air to heat the fire surface of the test piston and simulate the steady-state temperature field of the test piston.

[0011] (5) The oil supply circuit of the oil supply system designed in this invention uses an electromagnetic proportional valve as the core control component of the oil circuit. By steplessly adjusting the valve core opening, combined with a flow meter and a pressure transmitter, stepless control of the flow or pressure in the oil supply circuit is achieved, which has high accuracy and versatility. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the overall structure of the device of the present invention; Figure 2 This is a schematic diagram of the internal structure of the device of the present invention; Figure 3 This is a partial structural diagram of the internal structure of the device of the present invention; Figure 4 This is a schematic diagram of the structure of the present invention, in which the moving piston and the connecting rod are connected by bolts; Figure 5 This is a schematic diagram of the structure in which the moving piston and connecting rod of the present invention are connected by a hinge; Figure 6 This is a partial structural diagram of the intermediate body and its connecting parts according to an embodiment of the present invention; Figure 7 This is a schematic diagram of the constant temperature and pressure oil supply system of the present invention; Figure 8 This is an isometric view of the overall structure of the fuel injection block of the present invention; Figure 9 This is a cross-sectional view of the internal oil passages of the fuel injection block of the present invention; Figure 10 This is a schematic diagram of the overall structure of the test piston of the present invention; Figure 11 This is a cross-sectional view of the internal cooling oil cavity structure of the test piston of the present invention; Figure 12 This is a schematic diagram of the structure of the double-link temperature measuring lead mechanism of the present invention; Figure 13 This is a schematic diagram of the universal bearing in the double-link temperature measuring lead mechanism of the present invention. Figure 14 This is a schematic diagram of the lower stepped shaft in the double-link temperature measuring lead mechanism of the present invention. Figure 15 This is a cross-sectional view of the hot air guiding tool of the present invention.

[0013] In the diagram, the components are: 1. Test piston; 2. Upper stepped shaft; 3. Lower stepped shaft; 4. Support seat; 5. Oil pan; 6. Support seat bracket; 7. Motor bracket; 8. Variable frequency motor; 9. Coupling; 10. Crankshaft; 11. Connecting rod; 12. Cylinder liner; 13. Moving piston; 14. Intermediate body; 15. Outer cylinder liner; 16. Inner cylinder liner; 17. Connecting rod; 18. Base; 19. Top cover; 20. Outlet flange; 21. Inlet flange; 22. Platform; 23. Oil tank; 24. Oil filter; 25. Oil pump; 26. Valve. Block 26, overflow valve 27, pressure gauge 28, electromagnetic proportional valve 29, flow meter 30, pressure transmitter 31, oil inlet pipe 32, oil injection block 33, oil injection pipe 34, temperature sensor 35, heater 36, circulating oil pump 37, cooler 38, electromagnetic on / off valve 39, upper connecting rod 40, lower connecting rod 41, universal bearing 42, bearing seat 43, universal bearing baffle 44, swivel bearing 45; oil inlet passage 1-1, oil outlet passage 1-2, internal cooling oil chamber 1-3. Detailed Implementation

[0014] Specific embodiments of the present invention are given below. These specific embodiments are only used to further illustrate the present invention in detail and do not limit the scope of protection of the present invention.

[0015] The present invention provides an internal cooling oil chamber piston oscillation cooling test device (hereinafter referred to as the device), characterized in that the device includes a test piston 1, a platform 22, a body, a modular cylinder liner tooling, a motion mechanism, a hot air guiding tooling, a constant temperature and constant pressure oil supply system (hereinafter referred to as the oil supply system), a thermocouple and a double connecting rod temperature measuring lead mechanism. The machine body is fixed on platform 22; the modular cylinder liner fixture is fixed on the machine body; the test piston 1 is installed inside the modular cylinder liner fixture, forming a translational motion pair with the modular cylinder liner fixture; the motion mechanism drives the test piston 1 to reciprocate up and down inside the modular cylinder liner fixture; the hot air guide fixture is fixed on the modular cylinder liner fixture, guiding hot air to heat the firing surface of the test piston 1; the oil supply system provides controllable constant temperature and pressure oil to the test piston 1 to simulate the cooling conditions in the piston cooling test, and at the same time provides lubrication and cooling to the motion mechanism located below the test piston 1 through splashing, natural fall and other methods; the thermocouple measuring points are fixed on the corresponding measuring points of the test piston 1, the double-link temperature measuring lead mechanism fixes the thermocouple, and the thermocouple signal points pass through the modular cylinder liner fixture to connect to external data acquisition cards or NI boards and other signal acquisition devices, converting electrical signals into temperature signals, realizing real-time measurement and acquisition of the temperature signals of the measuring points of the test piston 1.

[0016] Preferably, the machine body includes a support base 4, an oil pan 5, and a support base bracket 6; the modular cylinder liner tooling includes an intermediate body 14, an outer cylinder liner 15, and an inner cylinder liner 16; the motion mechanism includes a variable frequency motor 8, a coupling 9, a crankshaft 10, a connecting rod 11, a cylinder liner 12, a moving piston 13, a connecting rod 17, and a rotating bearing 45. The oil supply system includes an oil tank 23, a constant pressure oil supply circuit, and a constant temperature oil circulation circuit; the constant pressure oil supply circuit includes an oil filter 24, an oil pump 25, a valve block 26, an overflow valve 27, a pressure gauge 28, an electromagnetic proportional valve 29, a flow meter 30, a pressure transmitter 31, an oil inlet pipe 32, an oil injection block 33, and an oil injection pipe 34; the constant temperature oil circulation circuit includes a temperature sensor 35, a heater 36, a circulating oil pump 37, a cooler 38, and an electromagnetic on / off valve 39; Platform 22 bears the weight of the entire device; support bracket 6 is fixed to platform 22 by anchor bolts; both sides of support 4 are fixed to their respective support brackets 6 by bolts; support 4 has a certain height, so that there is enough space below it to install oil pan 5; oil pan 5 is fixed to the bottom of support 4 and is used to collect the oil sprayed from the oil supply system to cool the test piston 1, and to ensure that excess oil in oil pan 5 can flow back to oil tank 23 of oil supply system through oil pipe under its own weight, so as to realize oil supply circulation; The housing of the variable frequency motor 8 is fixed on the platform 22, and the output shaft is fixedly connected to the input position of the crankshaft 10 through the coupling 9; the crankshaft 10 is rotatably mounted in the support base 4 through the rotating bearing 45; the cylinder liner 12 is fixed inside the support base 4; the moving piston 13 is slidably mounted inside the cylinder liner 12 and can reciprocate up and down along the inner surface of the cylinder liner 12; one end of the connecting rod 11 (the large end in this embodiment) is rotatably connected to the output position of the crankshaft 10, and the other end (the small end in this embodiment) is hinged to the moving piston 13 through the piston pin; the rotation of the variable frequency motor 8 thereby realizes the reciprocating up and down movement of the moving piston 13 inside the cylinder liner 12; The bottom of the intermediate body 14 is fixed to the top of the support base 4 by bolts; the bottom of the outer cylinder liner 15 is fixed to the top of the intermediate body 14 by bolts; the side wall of the intermediate body 14 has a through hole for the oil inlet pipe 32 and the thermocouple to pass through; the inner cylinder liner 16 is fixed in the outer cylinder liner 15; the test piston 1 and the inner cylinder liner 16 form a translational motion pair, and the test piston 1 reciprocates along the axis in the inner cylinder liner 16; one end of the connecting rod 17 (the large end in this embodiment) is fixed to the moving piston 13 by bolts or hinged by a piston pin, passes through the cavity between the intermediate body 14 and the inner cylinder liner 16, and the other end (the small end in this embodiment) is hinged to the test piston 1 by a piston pin, thereby transmitting the up-and-down reciprocating motion of the moving piston 13 to the test piston 1, so that the moving piston 13 and the test piston 1 move in the same way; One oil outlet of the oil tank 23 is connected to the oil inlet of the valve block 26 via a pipeline, on which an oil filter 24 and an oil pump 25 are installed; one oil outlet of the valve block 26 is connected to the oil inlet of the oil inlet pipe 32; the oil inlet pipe 32 is equipped with an electromagnetic proportional valve 29, a flow meter 30, and a pressure transmitter 31; the oil outlet of the oil inlet pipe 32 passes through a through hole in the side wall of the intermediate body 14 and is connected to the oil inlet of the injection block 33; the injection block 33 is fixed in the intermediate body 14 by threads; the injection... The oil inlet of pipe 34 is connected to the oil outlet of the oil injection block 33. The oil outlet extends into the inner cylinder liner 16 and sprays constant temperature and pressure oil onto the test piston 1 for cooling. The other oil outlet of valve block 26 is connected to a return port of oil tank 23 through a pipeline. An overflow valve 27 is installed on the pipeline. A pressure gauge 28 is installed on valve block 26. The pressure gauge 28 is used to observe the oil pressure at valve block 26 and ensure that the maximum pressure of the constant pressure oil supply circuit does not exceed the safety limit set by overflow valve 27. Temperature sensor 35 is installed inside oil tank 23 to measure the temperature of the oil in oil tank 23; heater 36 is installed inside oil tank 23 to heat the oil in oil tank 23; another oil outlet of oil tank 23 is connected to the oil inlet of circulating oil pump 37 through a pipeline; the oil outlet of circulating oil pump 37 is connected to the oil inlet of cooler 38 and solenoid shut-off valve 39 through a tee and pipeline respectively; the oil outlets of cooler 38 and solenoid shut-off valve 39 are both connected to another oil return port of oil tank 23 through a tee and pipeline.

[0017] Preferably, the oil pan 5 has a double-layered structure with a baffle of a certain height in the middle. This allows one side to retain the engine oil required for normal lubrication, while the excess oil supplied by the oil supply system flows over the baffle to the other side and then flows back to the oil tank 23 under its own weight, thus achieving the circulation of the engine oil.

[0018] Preferably, the device further includes a motor bracket 7; the motor bracket 7 is fixed to the platform 22 by bolts; the housing of the variable frequency motor 8 is fixed to the motor bracket 7 by bolts.

[0019] Preferably, the speed of the variable frequency motor 8 is adjustable. The required speed is set according to the actual working conditions of the test piston 1. The speed adjustment range is 0~2200 rpm, covering the common speed range of the internal cooling oil chamber piston.

[0020] Preferably, the variable frequency motor 8, the coupling 9, and the crankshaft 10 are coaxially connected.

[0021] Preferably, the outer rings of the two rotating bearings 45 are fixed to the front and rear parts of the support base 4, respectively, and the inner rings are fixedly connected to the outer side of the crankshaft 10 to support the crankshaft 10.

[0022] Preferably, the top end of the cylinder liner 12 is flush with the top end of the support 4, and the axial direction of the cylinder liner 12 is perpendicular to the axial direction of the crankshaft 10.

[0023] Preferably, the bottom end of the intermediate body 14 is aligned with the top end of the support 4 and fixed with bolts; the top end of the intermediate body 14 is aligned with the bottom end of the outer cylinder liner 15 and fixed with bolts.

[0024] Preferably, the top of the outer cylinder liner 15 is machined with a stepped groove; the inner cylinder liner 16 is fixed in the outer cylinder liner 15 through the stepped groove, and the top of the outer cylinder liner 15 is flush with the top of the inner cylinder liner 16.

[0025] Preferably, when the moving piston 13 and the connecting rod 17 are fixedly connected by bolts, the top of the moving piston 13 is machined with a threaded hole, and one end of the connecting rod 17 is a flange structure. The connecting rod 17 and the moving piston 13 are fixedly connected by bolts to realize the transmission of movement on both sides. When the piston pin is used for hinged connection, the moving piston 13 is a double-hole piston. One hole is hinged to the connecting rod 11 by a piston pin, and the other hole is connected to the connecting rod 17 by a piston pin to realize the transmission of movement on both sides.

[0026] Preferably, an oil filter 24 and an oil pump 25 are sequentially installed on the connecting pipeline between the oil tank 23 and the valve block 26.

[0027] Preferably, an electromagnetic proportional valve 29, a flow meter 30, and a pressure transmitter 31 are sequentially installed on the oil inlet pipe 32; the flow meter 30 and the pressure transmitter 31 monitor the flow and pressure of the constant pressure oil supply circuit, and the electromagnetic proportional valve 29 can steplessly adjust the opening of the valve core. Through the feedback from the flow meter 30 and the pressure transmitter 31, the flow and pressure of the oil output from the constant pressure oil supply circuit are accurately controlled.

[0028] Preferably, the oil outlet of the oil inlet pipe 32, the oil inlet and outlet of the oil injection block 33, and the oil inlet of the oil injection pipe 34 are machined with pipe threads, and the threaded connection between the parts ensures good sealing.

[0029] Preferably, the test piston 1 has an oil inlet passage 1-1, an oil outlet passage 1-2, and an internal cooling oil chamber 1-3; the internal cooling oil chamber 1-3 is located inside the test piston 1, with its inlet connected to the oil inlet passage 1-1 and its outlet connected to the oil outlet passage 1-2. Preferably, the oil passage structure, outlet position and outlet diameter of the fuel injection block 33 are customized according to the position and diameter of the oil inlet passage 1-1 of the test piston 1, so as to ensure that the oil outlet of the fuel injection pipe 34 is aligned with the oil inlet passage 1-1. Preferably, the oil injection pipe 34 injects controllable constant temperature and pressure engine oil into the oil inlet 1-1 of the test piston 1. The engine oil entering the internal cooling oil chamber 1-3 vibrates violently under the reciprocating motion of the test piston 1, and washes the wall of the internal cooling oil chamber 1-3. After the engine oil exchanges heat with the wall of the internal cooling oil chamber 1-3, it flows out from the oil outlet 1-2, thereby simulating the piston oscillation cooling mode of the internal cooling oil chamber.

[0030] Preferably, the cooler 38 is an air cooler.

[0031] Preferably, the hot air guiding fixture includes a base 18, a top cover 19, an air outlet flange 20, and an air inlet flange 21; The disc-shaped structure at the lower end of the base 18 is fixed to the top of the outer cylinder liner 15 by bolts, providing support for the hot air guiding fixture while pressing and fixing the inner cylinder liner 16 inside the outer cylinder liner 15. The cylindrical cavity structure in the middle of the base 18 provides space for the flow of hot air in the hot air guiding fixture. An exhaust pipe is opened on its side, and an exhaust port flange 20 is welded and fixed at the end of the exhaust pipe. The exhaust port flange 20 is used to connect with the high-temperature gas pipe to discharge the hot air after heating the test piston 1 into the atmosphere. The disc-shaped structure at the lower end of the top cover 19 is fixed to the top of the cylindrical cavity structure of the base 18 by bolts, realizing the alignment and fixation of the base 18 and the top cover 19. An air inlet flange 21 is welded and fixed at the top of the tubular channel in the middle of the top cover 19, which is used to connect with the high-temperature gas pipe, so that the hot air enters the cylindrical cavity of the base 18 through the air inlet flange 21 and the top cover 19 to heat the firing surface of the test piston 1.

[0032] Preferably, the double-link temperature measuring lead mechanism includes an upper link 40, a lower link 41, a universal bearing 42, a bearing seat 43, a universal bearing baffle 44, an upper stepped shaft 2, and a lower stepped shaft 3. One end of the upper connecting rod 40 is rotatably mounted in the connecting rod 17 via the upper stepped shaft 2, and the other end is rotatably connected to one end of the lower connecting rod 41; the bearing housing 43 is fixed inside the intermediate body 14 by bolts; the outer ring of the universal bearing 42 is fixed inside the bearing housing 43 by the universal bearing baffle 44, and the universal bearing baffle 44 is fixed on the bearing housing 43 by bolts; the other end of the lower connecting rod 41 is rotatably mounted in the inner ring of the universal bearing 42 via the lower stepped shaft 3; several through holes are opened on the upper connecting rod 40 and the lower connecting rod 41 as fixing holes for thermocouples; thermocouples... The thermocouple's measuring point is fixed on the corresponding measuring point of the test piston 1, and passes through the through holes on the upper connecting rod 40 and the lower connecting rod 41 in sequence, so that the thermocouple is flexibly fixed on the upper connecting rod 40 and the lower connecting rod 41 and moves synchronously with them, avoiding possible entanglement and breakage of the thermocouple during the rapid reciprocating motion of the test piston 1. It passes through the through hole in the side wall of the intermediate body 14 and exits the device. The thermocouple's signal point is connected to an external data acquisition card or NI board or other signal acquisition device to convert the electrical signal into a temperature signal, so as to realize the real-time measurement and acquisition of the temperature signal of the measuring point of the test piston 1.

[0033] Preferably, using cotter pins as the fixing method between connecting rod 17 and upper stepped shaft 2, between upper stepped shaft 2 and upper connecting rod 40, and between lower connecting rod 41 and lower stepped shaft 3 has two advantages: (1) it does not restrict the rotational freedom between the fixed parts, ensuring the relative movement between the parts; (2) it is easy to disassemble and assemble, and when replacing test pistons 1 of different diameters, the overall disassembly and assembly of the device is more convenient.

[0034] Preferably, the universal bearing 42 has three degrees of rotational freedom, making the movement smoother and preventing damage to the double-link temperature measuring lead mechanism due to motion interference.

[0035] Example 1: To simulate the oil oscillation cooling process of a real internally cooled oil chamber piston, and to obtain real-time temperature data at various measuring points on the piston under specified speed, heating temperature, and cooling oil parameters, the following parameters were selected for the test piston: diameter 110mm, height 99.5mm, piston stroke 145mm, connecting rod 11 length 240mm; hot air temperature at the piston top 600℃, flow rate 200m³ / h. 3 / h; The speed of the variable frequency motor 8 is 1000 r / min, the outlet diameter of the fuel injection pipe 34 is 5 mm, the oil temperature is 90℃, and the output pressure of the constant pressure oil supply circuit is 0.8 MPa. Under the above test conditions, it is necessary to measure the temperature change of the piston in the internal cooling oil chamber at each measuring point before and after oil cooling until the value tends to stabilize; Keeping other conditions unchanged, change the oil output pressure to 0.4 MPa, 0.6 MPa, 1.0 MPa, 1.2 MPa, and 1.4 MPa respectively, record the temperature change at each measuring point until the value tends to stabilize, and analyze the temperature change at each measuring point.

[0036] The method and steps for conducting the above-mentioned dynamic heat transfer test of piston oil oscillation cooling in the internal cooling oil chamber are as follows: Step 1: Install the modular cylinder liner tooling and oil injection block 33 designed for the test piston 1, weld the thermocouple onto the test piston 1, and lead the thermocouple out of the device through the double-link temperature measuring lead mechanism to connect to the external signal acquisition device, and complete the overall assembly and connection of the device. Step 2: The constant temperature oil circulation circuit starts working. The target temperature for oil heating is set. The heater 36 heats the oil in the oil tank 23 to the target temperature value and maintains the oil temperature in the oil tank 23 at the target value during the test. Preferably, in step 2, the oil temperature in the oil tank 23 is maintained at the target value, and the specific implementation method is as follows: First, the circulating oil pump 37 is started. When the temperature sensor 35 reads below the target temperature, the solenoid on / off valve 39 is opened, the heater 36 is started to heat the oil, and the cooler 38 is turned off. At this time, the oil flow in the constant temperature oil circulation circuit is from the oil tank 23 to the circulating oil pump 37. Most of the oil flows back to the oil tank 23 after passing through the solenoid on / off valve 39, and a small portion flows back to the oil tank 23 after passing through the cooler 38. At this time, the constant temperature oil circulation circuit accelerates the convective heat transfer of the oil in the oil tank 23. When the temperature sensor 35 reads above the target temperature, the solenoid on / off valve 39 is closed, the cooler 38 is started to cool the oil, and the heater 36 is turned off. At this time, the oil flow in the constant temperature oil circulation circuit is from the oil tank 23 to the circulating oil pump 37, flows back to the oil tank 23 after passing through the cooler 38, and the constant temperature oil circulation circuit accelerates the convective heat transfer of the oil in the oil tank 23 and cools the oil.

[0037] Step 3: While opening the constant temperature circulation circuit of the engine oil, start the hot air heating. The high temperature and constant flow of high temperature air enters the hot air guide fixture through the air inlet of the hot air guide fixture to heat the fire surface of the test piston 1. After heating, the hot air is discharged into the atmosphere through the air outlet of the hot air guide fixture. After starting the hot air heating, record the temperature signal of the test piston 1 collected by the thermocouple. At this time, the temperature signal value should gradually rise. Wait for the temperature signal to stabilize (i.e., the fluctuation range does not exceed ±1℃) before proceeding to step 4. Step 4: Start the flow meter 30 and pressure transmitter 31 of the constant pressure oil supply circuit, turn on the oil pump 25, and keep the valve core of the solenoid proportional valve 29 fully open. After the oil output from the oil pump 25 flows through the entire constant pressure oil supply circuit, the oil pressure in the constant pressure oil supply circuit will stabilize. At this time, the reading of the pressure transmitter 31 is the output pressure of the constant pressure oil supply circuit. Then, reduce the valve core opening of the solenoid proportional valve 29. The reading of the pressure transmitter 31 should decrease accordingly. When the reading decreases to a certain preset value (0.4MPa, 0.6MPa, 1.0MPa in this embodiment), the pressure will continue to decrease. The valve core opening of the electromagnetic proportional valve 29 is locked, and the setting of the constant pressure oil supply circuit is completed. Part of the oil output from the constant pressure oil supply circuit enters the internal cooling oil chamber 1-3 of the test piston 1 through the oil inlet 1-1 to cool the test piston 1. The other part of the oil that fails to enter the test piston 1 provides lubrication to the mechanical moving parts in the modular cylinder liner tooling and motion mechanism under the action of gravity and viscosity. Then it falls back into the oil pan 5 and finally flows back to the oil tank 23 under the action of gravity through the oil pipe, realizing the circulation of oil. Step 5: After the pressure transmitter 31 reading stabilizes in Step 4, start the variable frequency motor 8. Through the coupling 9, crankshaft 10, connecting rod 11, moving piston 13 and connecting rod 17, the fixed-axis rotation of the variable frequency motor 8 is transmitted and converted into the up-and-down reciprocating motion of the test piston 1 in the inner cylinder liner 16. To ensure the smooth acceleration of the entire motion mechanism, the speed of the variable frequency motor 8 is gradually increased to 1000 r / min at intervals of 200 r / min. Start the oscillation cooling test and record the thermocouple temperature signal value until it stabilizes (i.e., the fluctuation range does not exceed ±1℃). The recorded thermocouple temperature signal value is the test data. Step 6: After completing the piston oscillation cooling test under a specific constant pressure oil supply circuit output pressure in Step 5, adjust the output pressure of the constant pressure oil supply circuit to the next preset value according to the procedure in Step 4. Then repeat Step 5 and record the relevant thermocouple temperature signal data. After completing the test under all constant pressure oil supply circuit output pressure parameters, turn off the hot air supply in sequence, gradually reduce the speed every 200 r / min until the variable frequency motor 8 stops running, turn off the constant pressure oil supply circuit and the constant temperature oil circulation circuit, and end the test.

[0038] In addition to the piston oscillation cooling test with the output pressure of the constant pressure oil supply circuit as the test variable in the above test steps, this device also has the capability to perform piston oscillation cooling tests with engine speed, cooling oil temperature, and constant temperature oil supply flow rate as test variables. The methods are the same and will not be described in detail here.

[0039] Any aspects not covered in this invention are applicable to existing technologies.

Claims

1. A piston oscillation cooling test device with an internal cooling oil chamber, characterized in that, The device includes a test piston (1), a platform (22), a body, a modular cylinder liner tooling, a motion mechanism, a hot air guiding tooling, a constant temperature and pressure oil supply system, a thermocouple, and a double-linkage temperature measuring lead mechanism. The machine body is fixed on the platform (22); The modular cylinder liner fixture is fixed on the machine body; the test piston (1) is installed in the modular cylinder liner fixture, forming a translational motion pair with the modular cylinder liner fixture; the motion mechanism drives the test piston (1) to move up and down reciprocally in the modular cylinder liner fixture; the hot air guide fixture is fixed on the modular cylinder liner fixture to guide the hot air to heat the fire surface of the test piston (1); the oil supply system provides controllable constant temperature and pressure machine oil to the test piston (1) to simulate the cooling conditions in the piston cooling test, and at the same time provides lubrication and cooling to the motion mechanism located below the test piston (1); the thermocouple measuring point is fixed on the corresponding measuring point of the test piston (1), the double connecting rod temperature measuring lead mechanism fixes the thermocouple, and the thermocouple signal point passes through the modular cylinder liner fixture to connect to the external signal acquisition device, converting the electrical signal into a temperature signal, and realizing the real-time measurement and acquisition of the temperature signal of the measuring point of the test piston (1).

2. The internal cooling oil chamber piston oscillation cooling test device according to claim 1, characterized in that, The machine body includes a support base (4), an oil pan (5), and a support base bracket (6); the modular cylinder liner tooling includes an intermediate body (14), an outer cylinder liner (15), and an inner cylinder liner (16); the motion mechanism includes a variable frequency motor (8), a coupling (9), a crankshaft (10), a connecting rod (11), a cylinder liner (12), a moving piston (13), and a connecting rod (17); The oil supply system includes an oil tank (23), a constant pressure oil supply circuit and a constant temperature oil circulation circuit; the constant pressure oil supply circuit includes an oil filter (24), an oil pump (25), a valve block (26), an overflow valve (27), a pressure gauge (28), an electromagnetic proportional valve (29), a flow meter (30), a pressure transmitter (31), an oil inlet pipe (32), an oil injection block (33), and an oil injection pipe (34); the constant temperature oil circulation circuit includes a temperature sensor (35), a heater (36), a circulating oil pump (37), a cooler (38), and an electromagnetic on / off valve (39); The two sides of the support base (4) are fixed to the platform (22) by their respective support base brackets (6); the oil pan (5) is fixed to the bottom of the support base (4); the housing of the variable frequency motor (8) is fixed on the platform (22), and the output shaft is fixedly connected to the input position of the crankshaft (10) through the coupling (9); the crankshaft (10) is rotatably installed in the support base (4); the cylinder liner (12) is fixed inside the support base (4); the moving piston (13) is slidably installed in the cylinder liner (12); one end of the connecting rod (11) is rotatably connected to the output position of the crankshaft (10), and the other end is hinged to the moving piston (13); The intermediate body (14) is fixed to the top of the support base (4); the outer cylinder liner (15) is fixed to the top of the intermediate body (14); the side wall of the intermediate body (14) has a through hole for the oil inlet pipe (32) and the thermocouple to pass through; the inner cylinder liner (16) is fixed in the outer cylinder liner (15); the test piston (1) and the inner cylinder liner (16) form a translational motion pair, and the test piston (1) reciprocates along the axis in the inner cylinder liner (16); one end of the connecting rod (17) is fixedly connected or hinged to the moving piston (13), passes through the cavity of the intermediate body (14) and the inner cylinder liner (16), and the other end is hinged to the test piston (1); One oil outlet of the oil tank (23) is connected to the oil inlet of the valve block (26) via a pipeline, and an oil filter (24) and an oil pump (25) are installed on the pipeline; one oil outlet of the valve block (26) is connected to the oil inlet of the oil inlet pipe (32); an electromagnetic proportional valve (29), a flow meter (30) and a pressure transmitter (31) are installed on the oil inlet pipe (32); the oil outlet of the oil inlet pipe (32) passes through a through hole in the side wall of the intermediate body (14) and is connected to the oil inlet of the spray block (33); the spray block (33) is fixed in the intermediate body (14); the spray The oil inlet of the oil pipe (34) is connected to the oil outlet of the oil injection block (33), and the oil outlet extends into the inner cylinder liner (16) to spray constant temperature and pressure oil onto the test piston (1) for cooling; the other oil outlet of the valve block (26) is connected to a return port of the oil tank (23) through a pipeline, and an overflow valve (27) is installed on the pipeline; a pressure gauge (28) is installed on the valve block (26), and the pressure gauge (28) is used to observe the oil pressure at the valve block (26) and ensure that the maximum pressure of the constant pressure oil supply circuit does not exceed the safety limit set by the overflow valve (27); A temperature sensor (35) is installed inside the oil tank (23) to measure the temperature of the oil in the oil tank (23); a heater (36) is installed inside the oil tank (23) to heat the oil in the oil tank (23); another oil outlet of the oil tank (23) is connected to the oil inlet of the circulating oil pump (37) through a pipeline; the oil outlet of the circulating oil pump (37) is connected to the oil inlet of the cooler (38) and the solenoid on / off valve (39) through a tee and a pipeline respectively; the oil outlets of the cooler (38) and the solenoid on / off valve (39) are both connected to another oil return port of the oil tank (23) through a tee and a pipeline.

3. The internal cooling oil chamber piston oscillation cooling test device according to claim 2, characterized in that, The interior of the oil pan (5) has a double-layered structure with a baffle in the middle.

4. The internal cooling oil chamber piston oscillation cooling test device according to claim 2, characterized in that, The device also includes a motor bracket (7); the motor bracket (7) is fixed on the platform (22); the housing of the variable frequency motor (8) is fixed on the motor bracket (7).

5. The internal cooling oil chamber piston oscillation cooling test device according to claim 2, characterized in that, The outer rings of the two rotating bearings 45 are fixed to the front and rear of the support base (4) respectively, and the inner rings are fixedly connected to the outer side of the crankshaft (10) to support the crankshaft (10).

6. The internal cooling oil chamber piston oscillation cooling test device according to claim 2, characterized in that, An oil filter (24) and an oil pump (25) are installed sequentially on the connecting pipeline between the oil tank (23) and the valve block (26).

7. The internal cooling oil chamber piston oscillation cooling test device according to claim 2, characterized in that, An electromagnetic proportional valve (29), a flow meter (30), and a pressure transmitter (31) are sequentially installed on the oil inlet pipe (32).

8. The internal cooling oil chamber piston oscillation cooling test device according to claim 2, characterized in that, The test piston (1) has an oil inlet passage (1-1), an oil outlet passage (1-2), and an internal cooling oil chamber (1-3); the internal cooling oil chamber (1-3) is located inside the test piston (1), with its inlet connected to the oil inlet passage (1-1) and its outlet connected to the oil outlet passage (1-2); the oil outlet of the injection pipe (34) is aligned with the oil inlet passage (1-1).

9. The internal cooling oil chamber piston oscillation cooling test device according to claim 1, characterized in that, The hot air guiding fixture includes a base (18), a top cover (19), an outlet flange (20), and an inlet flange (21). The disc-shaped structure at the lower end of the base (18) is fixed to the top of the outer cylinder liner (15), providing support for the hot air guiding fixture while pressing and fixing the inner cylinder liner (16) inside the outer cylinder liner (15); the cylindrical cavity structure in the middle of the base (18) provides space for the flow of hot air in the hot air guiding fixture, and an exhaust pipe is opened on its side. An exhaust port flange (20) is fixed at the end of the exhaust pipe. The exhaust port flange (20) is used to connect to the high-temperature gas pipe and heat the test piston (1) behind it. Hot air is discharged into the atmosphere; the disc-shaped structure at the lower end of the top cover (19) is fixed to the top of the cylindrical cavity structure of the base (18) to achieve alignment and fixation between the base (18) and the top cover (19); the top of the tubular channel in the middle of the top cover (19) is fixed with an air inlet flange (21) for connecting with a high-temperature gas pipe, so that hot air enters the cylindrical cavity of the base (18) through the air inlet flange (21) and the top cover (19) to heat the fire surface of the test piston (1).

10. The internal cooling oil chamber piston oscillation cooling test device according to claim 1, characterized in that, The double-link temperature measuring lead mechanism includes an upper link (40), a lower link (41), a universal bearing (42), a bearing seat (43), a universal bearing baffle (44), an upper stepped shaft (2), and a lower stepped shaft (3). One end of the upper connecting rod (40) is rotatably installed in the connecting rod (17) via the upper stepped shaft (2), and the other end is rotatably connected to one end of the lower connecting rod (41); the bearing seat (43) is fixed inside the intermediate body (14); the outer ring of the universal bearing (42) is fixed inside the bearing seat (43) via the universal bearing baffle (44), and the universal bearing baffle (44) is fixed on the bearing seat (43); the other end of the lower connecting rod (41) is rotatably installed in the inner ring of the universal bearing (42) via the lower stepped shaft (3); several through holes are opened on the upper connecting rod (40) and the lower connecting rod (41) as fixing holes for thermocouples; the measuring points of the thermocouples are fixed on the corresponding measuring points of the test piston (1), and pass through the through holes on the upper connecting rod (40) and the lower connecting rod (41) in sequence, and pass through the through holes on the side wall of the intermediate body (14) to exit the device; the signal points of the thermocouples are connected to the external signal acquisition device.

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