An engine valve wear test system

Abstract

The application relates to the technical field of testing, and particularly discloses an engine valve wear testing system, which is integrated with a sample installation assembly, a mechanical loading assembly, an environment and temperature control assembly, a motion control and rotation assembly, a physical quantity measurement assembly and a wear determination module on a test rack, can reproduce the annular contact working condition of a valve / valve seat under the conditions of controllable mechanical load, temperature field and combustion atmosphere, can synchronously acquire force, displacement, temperature, rotating speed and wear profile data, can realize quantitative testing and comparison of the physical wear characteristics of different valve materials and valve seat materials by calculating the wear rate and the wear coefficient, can reduce the dependence on ignition testing of an entire machine, and can provide reliable data support for valve structure design, material selection, life evaluation and simulation modeling.

Description

Technical Field

[0001] This invention relates to the field of testing technology, and more specifically, to an engine valve wear testing system. Background Technology

[0002] Internal combustion engine valves and their mating seats are key components controlling the intake and exhaust processes. They operate under high temperature, high pressure, periodic impacts, and complex combustion atmospheres for extended periods. Wear in their contact areas directly affects the engine's sealing performance, thermal efficiency, and reliability. This is especially true in large-bore gas turbine engines and high-load diesel engines, where combustion pressure and temperature are constantly increasing to meet emission reduction and thermal efficiency requirements, while lubricating additives in the fuel are reduced. This results in the valve / seat friction pair being in a state of dry friction or boundary lubrication for extended periods, exacerbating wear problems. Practical applications show that valve wear not only shortens overhaul cycles but can also lead to premature failure, resulting in significant maintenance costs and safety risks.

[0003] In existing technologies, the evaluation of valve wear performance mainly relies on two methods: whole-engine ignition testing and simplified friction testing. On the one hand, whole-engine ignition testing can realistically reproduce the engine's operating environment, and the obtained wear data is highly correlated with actual applications. However, this type of test has a long cycle, high cost, and the operating conditions cannot be completely and precisely controlled. Furthermore, it is difficult to systematically separate the influence of different factors such as valve closing impact load and combustion peak pressure on wear, which is not conducive to establishing a material wear database that can be used in the design stage. On the other hand, although conventional pin-disc or block-disc friction and wear testing machines are low in cost and have controllable parameters, their contact geometry, temperature field, and contact pressure distribution differ significantly from the actual valve / valve seat annular contact. This often results in wear volume and wear coefficients that deviate significantly from actual engine operating conditions, limiting the direct application of test results in valve design.

[0004] In 2022, Zhu Feng published a research paper in the journal *Internal Combustion Engines and Parts* on the experimental characteristics of valves and seat rings in heavy-duty LNG engines, introducing an experimental engine, such as... Figure 2As shown, the engine is a 6-cylinder LNG in-line turbocharged exhaust gas engine, and the aftertreatment system is equipped with a TWC three-way catalytic converter. However, the test engine cannot independently adjust the valve closing speed and peak combustion pressure on the same platform, making it difficult to distinguish the contributions of impact wear and sliding wear. In addition, some test devices have relatively coarse control over temperature and atmosphere, failing to conduct long-term wear tests under typical combustion environments such as high-temperature oxidizing or water-rich environments. Wear data obtained only at room temperature or in simple atmospheres cannot reflect real operating conditions. Furthermore, existing testing machines often focus on qualitative comparison of wear trends of different materials, lacking complete synchronous measurement of force, displacement, temperature, and wear morphology. They do not systematically calculate wear rate and wear coefficient based on contact pressure, relative sliding distance, and wear volume, resulting in insufficient quantitative testing of the physical wear characteristics of materials.

[0005] In summary, existing technologies for testing the wear of engine valve and valve seat materials have the following shortcomings: 1. There is a lack of a comprehensive testing platform that can realistically reproduce the valve annular contact condition and accurately control key parameters such as valve closing speed, peak combustion pressure, temperature, and atmosphere; 2. There is a lack of a testing system for systematically measuring the wear rate and wear coefficient of engine valve / valve seat mating materials under different loads and environmental conditions, making it difficult to form a material database that can be directly used for structural design and life assessment; 3. There is a lack of a unified measurement and data processing link between mechanical load, temperature field, and wear profile, making it difficult to effectively interface the test results with numerical simulation models.

[0006] Therefore, it is necessary to provide a wear testing system for engine valve and valve seat friction pairs to achieve quantitative testing and analysis of the physical wear characteristics of materials, reduce reliance on whole-engine ignition testing, and provide a basis for engine valve design and material selection. Summary of the Invention

[0007] To overcome the aforementioned deficiencies of the prior art, this invention provides an engine valve wear testing system. This system obtains representative wear morphology and wear rate under controllable mechanical, thermal, and environmental conditions, and calculates the wear coefficient using a contact condition wear algorithm. This allows for the quantitative testing and analysis of the physical wear characteristics of engine valve materials and valve seat materials, thereby solving the problems mentioned in the background art.

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] An engine valve wear testing system, comprising:

[0010] The sample mounting assembly coaxially clamps and positions the engine valve and valve seat samples.

[0011] The mechanical loading assembly applies dynamic closing impact loads and static combustion peak pressures to the engine valves.

[0012] The ambient temperature control components establish high temperature and combustion conditions at the contact zone between the engine valves and valve seats.

[0013] The motion control and rotation components drive the engine valves to rotate around their axis during the test.

[0014] The physical quantity measurement component converts the physical changes generated during the experiment into electrical signals.

[0015] The wear measurement module calculates the wear rate and wear coefficient to test and analyze the physical wear properties of the material being tested.

[0016] As a further aspect of the present invention, the sample mounting assembly, which coaxially clamps and positions engine valve and valve seat samples, includes the following specific details: The sample mounting assembly is fixedly disposed in the middle of the test frame, which is a rigid metal frame structure. The sample mounting assembly includes a valve seat fixing seat, a valve guide seat, a valve stem, and a valve clamping head. The valve seat fixing seat has a mounting hole that matches the geometry of the valve seat sample being tested, for detachably mounting valve seat samples of different diameters and seat angles and positioning them axially and radially. The valve guide seat has a guide hole that mates with the valve stem, ensuring that the valve stem remains coaxial with the valve seat axis during reciprocating motion and slow rotation. The valve clamping head is connected to the tail end of the valve stem via a threaded connection or clamping method to achieve rapid disassembly and assembly and stable clamping of the engine valve sample.

[0017] As a further aspect of the present invention, a mechanical loading assembly applies a dynamic closing impact load and a static combustion peak pressure to the engine valve, comprising the following specific components: The mechanical loading assembly, which applies a dynamic closing impact load and a static combustion peak pressure to the engine valve, includes a first hydraulic loading unit and a second hydraulic loading unit. The first hydraulic loading unit is arranged along the engine valve axis and connected to the tail end of the engine valve, and is used to drive the engine valve to reciprocate under a predetermined stroke and speed curve to simulate the opening and closing process of the engine valve, generating an adjustable valve closing impact load; the second hydraulic loading unit is connected to the working surface of the engine valve head through a loading punch, and applies an axial static load to the valve head after the engine valve is closed, to simulate the contact pressure under the action of the combustion peak pressure.

[0018] As a further aspect of the present invention, an environment and temperature control component establishes high temperature and combustion conditions in the contact zone between the engine valve and the valve seat, including the following specific contents: The environment and temperature control component establishes high temperature and combustion conditions in the contact zone between the engine valve and the valve seat, comprising an environmental cavity surrounding the contact zone between the engine valve and the valve seat, a gas supply and discharge unit for introducing single or mixed gases into the environmental cavity, an induction heating unit disposed around the engine valve head, and a cooling water jacket disposed around the valve seat, wherein the environmental cavity forms a thermally insulated space for wear testing under predetermined temperature and atmosphere conditions.

[0019] As a further aspect of the present invention, the motion control and rotation assembly drives the engine valve to rotate around its axis during the test, including the following specific contents: the motion control and rotation assembly drives the engine valve to rotate around its axis during the test, which includes a valve spring assembly that matches the actual valve train of the engine and a rotation mechanism that drives the valve to rotate slowly around its axis, for realizing the pitch movement and circumferential uniform wear of the valve during the test.

[0020] As a further aspect of the present invention, the physical quantity measurement component converts the physical changes generated during the test into electrical signals, including the following specific contents: The physical quantity measurement component converts the physical changes generated during the test into electrical signals, which includes a force sensor connected in series with the first hydraulic loading unit and the second hydraulic loading unit respectively, a displacement sensor for measuring valve stroke, a temperature sensor arranged inside or on the surface of the valve head and valve seat, a speed sensor and an angle sensor for detecting the valve rotation state, and a wear profile acquisition device for acquiring the wear morphology of the valve and valve seat contact surfaces.

[0021] As a further aspect of the present invention, a wear measurement module calculates the wear rate and wear coefficient to test and analyze the physical wear properties of the tested material. This includes the following specific steps: The wear measurement module uses impact load, axial static load, and displacement data, combined with the width and average radius of the contact band between the engine valve and valve seat, to calculate the contact force and equivalent contact area between the engine valve and valve seat, obtaining the average contact pressure. Then, using the engine valve's rotational speed and angular displacement, combined with the average radius of the contact band, it calculates the relative sliding speed and circumferential sliding distance between the engine valve and valve seat in the circumferential direction, and estimates the radial micro-slip component, comparing it with the circumferential... The cumulative relative slip distance is obtained by superimposing the slip component vectors. The wear measurement module calls the wear profile acquisition device to obtain wear depth distribution data at different test time nodes, performs numerical integration on the wear profile of the engine valve and valve seat contact zone along the circumferential and radial directions, calculates the wear volume corresponding to each measurement time, and calculates the average wear volume increment by combining the time interval between two adjacent profiles. Then, the wear rate under the corresponding working condition is calculated with time as the independent variable. Finally, based on the average contact pressure, equivalent contact area, cumulative relative slip distance and wear volume, the wear coefficient under the corresponding test working condition is calculated using the contact working condition wear algorithm.

[0022] The technical effects and advantages of this invention's engine valve wear testing system are as follows: This invention integrates a sample mounting assembly, a mechanical loading assembly, an environmental and temperature control assembly, a motion control and rotation assembly, a physical quantity measurement assembly, and a wear measurement module on a test frame. While maintaining the true annular contact geometry of the valve / valve seat, it controllably applies valve closing impact loads and simulated combustion peak pressures on the same platform using a first hydraulic loading unit and a second hydraulic loading unit, respectively. Combined with an environmental chamber, induction heating, a cooling water jacket, and an adjustable atmosphere, it reproduces actual operating conditions under high-temperature combustion. Furthermore, it measures force, displacement, temperature, valve rotation state, and wear. The profile is collected synchronously, and the wear rate and wear coefficient are calculated using a contact condition wear algorithm based on the average contact pressure, equivalent contact area, cumulative relative slip distance, and wear volume. A correspondence between "operating condition parameters – wear rate – wear coefficient" is established, supporting lateral comparison and wear mechanism analysis of different valve / seat material combinations under the same operating conditions. This enables quantitative testing and comprehensive evaluation of the physical wear characteristics of engine valve and valve seat mating materials, overcoming the shortcomings of existing whole-engine ignition test cycles that are long, costly, and simplified friction tests that deviate significantly from real operating conditions. It provides a reliable experimental data foundation for valve structure design, material selection, life estimation, and simulation modeling. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of an engine valve wear testing system according to the present invention.

[0024] Figure 2 This is a schematic diagram of an LNG engine used for testing existing technology.

[0025] Figure 3 This is a schematic diagram of the contact zone and wear profile of the engine valve and valve seat in this invention. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] Example 1

[0028] like Figure 1 As shown, the present invention provides an engine valve wear testing system, comprising:

[0029] The sample mounting assembly coaxially clamps and positions the engine valve and valve seat samples.

[0030] The mechanical loading assembly applies dynamic closing impact loads and static combustion peak pressures to the engine valves.

[0031] The ambient temperature control components establish high temperature and combustion conditions at the contact zone between the engine valves and valve seats.

[0032] The motion control and rotation components drive the engine valves to rotate around their axis during the test.

[0033] The physical quantity measurement component converts the physical changes generated during the experiment into electrical signals.

[0034] The wear measurement module calculates the wear rate and wear coefficient to test and analyze the physical wear properties of the material being tested.

[0035] Furthermore, the sample mounting assembly is fixedly installed in the middle of the test frame. The test frame is a rigid metal frame structure with sufficient rigidity. Under test load, its elastic and torsional deformations are negligible, serving as the installation and stress reference for each functional component. The sample mounting assembly includes a valve seat fixing seat, a valve guide seat, a valve stem, and a valve clamping head, which are mechanically connected to form an integral rigid support. The valve seat fixing seat has mounting holes that match the geometry of the valve seat sample being tested, allowing for the detachable installation of valve seat samples with different diameters and seat angles and reliable positioning in the axial and radial directions. The valve guide seat has guide holes that mate with the valve stem, ensuring that the valve stem remains coaxial with the valve seat axis during reciprocating motion and slow rotation. The valve clamping head is connected to the tail end of the valve stem via threads or clamps, enabling quick installation and removal of the engine valve sample.

[0036] With the above structure, the conical working part of the engine valve head and the seat ring working surface of the valve seat sample are precisely arranged relative to each other in the sample mounting assembly. After axial compression, they form a closed annular contact band in the circumferential direction, which is used to reproduce the real contact state between the engine valve and the valve seat under controlled mechanical load and environmental conditions, and to provide stable geometric boundary conditions for subsequent mechanical loading and wear testing.

[0037] Furthermore, the mechanical loading assembly applies controllable dynamic closing impact loads and static combustion peak pressures to the valves through two sets of hydraulic loading units at the tail end and valve head, enabling the valves and valve seats to achieve a force and contact pressure state similar to that of an actual engine during the test. The mechanical loading module assembly is arranged at both ends of the engine valve axis where the sample mounting assembly is located, forming a continuous force chain along the engine valve direction. It includes a first hydraulic loading unit and a second hydraulic loading unit. The first hydraulic loading unit is rigidly connected to the valve clamping head at the tail end of the engine valve via a loading push rod. Its direction of action coincides with the engine valve axis. A servo hydraulic cylinder drives the loading push rod to reciprocate according to a predetermined lift and speed curve, thereby enabling the engine valves to achieve opening and closing strokes corresponding to the actual valve train during the test. During the process of the engine valve closing from the open position to the valve seat, an adjustable valve closing speed and impact load are generated to simulate the wear conditions caused to the valve / valve seat contact zone during the valve closing phase in the engine.

[0038] The second hydraulic loading unit is arranged on one side of the engine valve head. It contacts the working surface or back of the engine valve head through the loading punch. After the engine valve is closed by the first hydraulic loading unit and tightly fits the valve seat, the second hydraulic loading unit continuously acts on the engine valve head in the form of axial static load, so that a contact pressure field equivalent to the peak combustion pressure of the engine is established between the engine valve head and the working surface of the valve seat, which is used to reproduce the high temperature sliding wear condition under the action of combustion pressure.

[0039] The first hydraulic loading unit and the second hydraulic loading unit form a load closed loop through the test frame and the sample mounting assembly. The first hydraulic loading unit is used to provide controllable periodic motion and dynamic impact, and the second hydraulic loading unit is used to provide controllable static or slowly varying axial clamping force. The two work together to enable the engine valves and valve seats to obtain a stress state and contact pressure distribution similar to the actual engine operating conditions under laboratory conditions.

[0040] Furthermore, the environmental and temperature control components are arranged around the engine valve and valve seat contact zone (also known as the engine valve and valve seat contact area, which refers to the annular contact zone formed after the working surface of the engine valve head and the working surface of the valve seat are axially pressed together) to provide a controllable temperature field and atmospheric conditions during the wear test. It includes an environmental chamber fixed on the test frame, a gas supply and exhaust unit, an induction heating unit, and a cooling water jacket.

[0041] The environmental cavity adopts a shell structure that surrounds the contact zone between the engine valve head and the valve seat sample. The inner shell is arranged closely around the valve seat sample, and a heat insulation structure is set between the outer and inner layers, so that the environmental cavity forms a relatively independent thermal insulation space.

[0042] The environmental cavity is equipped with an air inlet and an exhaust outlet connected to the gas supply and exhaust unit. A single or mixed gas composed of inert gas or simulated combustion gas is introduced into the environmental cavity through pipelines. The atmosphere composition and pressure are controlled by the flow and pressure regulation and exhaust unit, thereby reproducing the engine combustion environment under different oxygen contents and different gas ratios.

[0043] An induction heating unit is installed around the engine valve head. The induction coil in the induction heating unit is connected to a high-frequency power supply to locally heat the engine valve head, so that the working surface of the engine valve reaches a predetermined high temperature.

[0044] An annular cooling water jacket is installed on the outside of the valve seat. The cooling water jacket is connected to a constant temperature cooling water source through inlet and outlet water pipes to cool one side of the valve seat. The induction heating unit and the cooling water jacket work together to establish a temperature gradient similar to the actual working conditions on the contact zone between the engine valve and the valve seat. Combined with the thermal insulation effect of the environmental cavity and temperature monitoring methods, the contact zone can operate stably for a long time under predetermined temperature and atmosphere conditions, thereby providing a reliable environmental boundary for obtaining representative valve wear data and material wear characteristics.

[0045] Furthermore, the motion control and rotation assembly is arranged along the engine valve axis between the sample mounting assembly and the mechanical loading assembly. The motion control and rotation assembly includes a valve spring assembly that matches the actual valve train of the engine and a rotation mechanism that drives the engine valve to rotate slowly around its axis. The valve spring assembly is installed near the valve clamping head and forms an elastic mechanical circuit with the sample mounting assembly and the test frame. When the first hydraulic loading unit drives the engine valve to reciprocate, it provides the same level of reset force and preload force as the original engine, so that the lift, closing process and reseating characteristics of the engine valve are consistent with the actual machine conditions.

[0046] The rotating mechanism is connected to the valve stem via a coupling or torque transmission structure. Its body is fixed on the test frame. During the test, it drives the engine valve to rotate continuously or intermittently around its own axis at a low speed, so that the contact zone between the engine valve head and the valve seat participates in bearing and wear in the circumferential direction in turn, thereby avoiding uneven wear caused by long-term repeated impact and compression in local areas.

[0047] The motion control and rotation component works in conjunction with the mechanical loading component to comprehensively adjust the kinematic conditions of the contact zone by controlling the pitch movement and circumferential rotation of the valve while maintaining the predetermined valve lift curve and closing speed. This makes the wear morphology and wear rate obtained during the test closer to the annular uniform wear state under the long-term operation of the actual engine.

[0048] Furthermore, the physical quantity measurement components are distributed across the mechanical loading component path, the sample mounting component area, the environmental cavity, and the rotating mechanism, forming a unified detection link for the test conditions. Force sensors are connected in series in the force transmission paths of the first and second hydraulic loading units to measure the impact load during valve closing and the axial static load during the simulated peak combustion pressure stage in real time. Displacement sensors are arranged in the engine valve movement direction to measure the engine valve stroke, acquiring data on engine valve lift, closing displacement, and minor elastic deformation displacement of the valve seat. Temperature sensors are attached to the inside or surface of the engine valve head and seat, and gas temperature monitoring points are arranged in the environmental cavity when necessary to accurately reflect the temperature distribution of the contact zone between the engine valve and seat and the surrounding medium. Speed ​​sensors and angle sensors are installed on the rotating mechanism. This is used to detect the speed and angular displacement of the engine valve's rotation around its axis; in addition, the physical quantity measurement component also includes a wear profile acquisition device for acquiring the wear morphology of the contact surface of the engine valve and valve seat. By imprinting the contact zone within a predetermined test interval and scanning the imprint or sample surface using profile measurement methods, raw data of wear depth distribution is obtained. This converts mechanical load (impact load during valve closing and axial static load during the simulated peak combustion pressure stage), motion state (engine valve lift, closing displacement, and seat ring micro-elastic deformation displacement data, engine valve rotation speed and angular displacement around its axis), temperature field (temperature distribution of the contact zone between the engine valve and valve seat and the surrounding medium), and wear morphology (raw data of wear depth distribution) into electrical signals that can be analyzed by the wear measurement module, providing a complete test basis for calculating wear rate and wear coefficient. Figure 3 The diagram illustrates the process by which the wear profile acquisition device obtains the raw data of the wear depth distribution. Figure 3 In the middle: the upper part is the conical surface of the engine valve head, and the lower part is the conical surface of the valve seat ring. The two form a narrow annular contact band in the circumferential direction. Figure 3 The right side of the image shows a magnified view of the contact zone, with the magnified frame outlining the area. The magnified view shows the undulating contour curve of the wear surface, and a contour measurement scan line along the contact zone, representing the wear depth acquisition process.

[0049] Furthermore, under preset test conditions, the wear measurement module is electrically connected to a force sensor, displacement sensor, temperature sensor, speed sensor, rotation angle sensor, and wear profile acquisition device. It synchronously acquires the impact load during valve closing and the axial static load signal during the peak combustion pressure stage, the engine valve lift and closing displacement, the seat ring micro-elastic deformation displacement signal, the speed and angular displacement signal of the engine valve rotation around the axis, the temperature signal of the contact zone between the engine valve and the valve seat and the surrounding medium, and the raw data of wear depth distribution acquired at intervals. The module calibrates, denoises, and aligns the time axis of the above-mentioned signals to establish a raw dataset of "force-displacement-temperature-speed-wear profile" described by a unified time reference.

[0050] Based on time synchronization, the wear measurement module utilizes the impact load during valve closing, simulated combustion peak pressure stage, and engine valve lift, closing displacement, and seat ring micro-elastic deformation displacement data from the displacement sensor. Combined with the width and average radius of the engine valve-seat contact zone, it uses a ring-shaped uniform pressure approximation to calculate the contact force and equivalent contact area between the engine valve and seat at each moment. This yields the peak impact load during valve closing and the average contact pressure during combustion peak pressure. Simultaneously, it reconstructs the engine valve lift curve, closing speed, and seat ring elastic deformation based on the displacement sensor output. Furthermore, it interpolates and statistically analyzes the temperature sensor measurements in the valve head, seat, and ambient cavity to obtain the temperature distribution of the engine valve-seat contact zone and surrounding medium under each test condition, forming a set of operating condition parameters containing "contact pressure-displacement-temperature" information.

[0051] The wear measurement module utilizes the engine valve rotation speed output by the speed sensor and the angular displacement output by the angle sensor, combined with the known average radius of the engine valve-valve seat contact zone, to calculate the relative sliding speed of the engine valve and valve seat in the circumferential direction and the circumferential sliding distance within each test time period, based on the rigid body circular motion relationship. Simultaneously, based on the elastic deformation of the valve head and the elastic deformation displacement of the valve seat ring, the radial micro-slip component caused by contact deformation or angular deviation is estimated, and then vector or scalar superimposed with the circumferential sliding component. Integration on the time axis yields the cumulative relative sliding distance of the engine valve-valve seat contact zone within the current test condition and test duration.

[0052] Given the contact conditions and cumulative slip, the wear measurement module calls the wear profile acquisition device to obtain wear depth distribution data at different test time points. It performs numerical integration on the wear profile of the engine valve and valve seat contact zone along the circumferential and radial directions, calculates the wear volume corresponding to each measurement time, and combines the time interval between two adjacent profile measurements to obtain the average wear volume increment within that time period. Then, it calculates the wear rate under the corresponding working condition with time as the independent variable, thereby converting the wear morphology into a quantifiable wear volume-time or wear volume-cycle number relationship.

[0053] Finally, the wear measurement module calculates the wear coefficient under the corresponding test condition based on the average contact pressure, equivalent contact area, cumulative relative slip distance, and wear volume using a contact condition wear algorithm. This includes: multiplying the average contact pressure by the equivalent contact area to obtain the average normal load acting on the contact strip between the engine valve and the valve seat; then combining the cumulative relative slip distance with the average normal load to obtain a normalized reference quantity characterizing the "total workload" of frictional contact under this condition; and finally, comparing the wear volume obtained by integration through the wear profile acquisition device with the normalized reference quantity, and using the ratio of the wear volume to the average normal load and the relative slip distance as the wear coefficient under this test condition.

[0054] In this embodiment, based on the calculated wear rate and wear coefficient, the wear measurement module repeats the test under different working conditions (including different contact pressures, temperatures, atmosphere compositions, valve closing speeds, and rotation speeds), as shown in Table 1, to form a correspondence between "working condition parameters - wear rate - wear coefficient", which is used to characterize the wear resistance and wear sensitivity of the combination of engine valve material and valve seat material under various typical working conditions.

[0055] Table 1. Test results of wear on engine valve and valve seat materials under different operating conditions.

[0056] As shown in Table 1, under the same temperature and atmosphere conditions (conditions 1→2), the wear rate and wear coefficient both increased with the contact pressure increasing from 60 MPa to 80 MPa, indicating that wear in this material combination intensifies with increasing load. Under the same pressure (conditions 2→3), increasing the temperature from 330℃ to 450℃ significantly increased the wear rate and wear coefficient, reflecting that high temperature enhances adhesive / oxidative wear. Reducing the oxygen content under high temperature and high pressure (conditions 3→4) significantly decreased the wear rate and wear coefficient, indicating that the oxygen-rich atmosphere exacerbated the wear on the material. Material oxidation wear; when the contact pressure and temperature remain constant, increasing the valve closing speed (conditions 1 to 5) leads to more severe impact and a slight increase in wear, while increasing the valve rotation speed (conditions 1 to 6) helps to make the circumferential wear of the contact zone more uniform, and the overall wear rate and coefficient actually decrease; when the pressure, temperature, and oxygen content are increased simultaneously while the rotation speed is decreased (condition 7), the maximum wear rate and wear coefficient appear, representing the most severe material wear under extremely harsh conditions, while under similar high pressure and high temperature conditions, reducing the oxygen content and increasing the rotation speed (condition 8) can alleviate wear to some extent. Through this correspondence between "condition parameters - wear rate - wear coefficient", the physical wear properties of this valve / seat material combination under different loads, temperatures, and atmospheres can be quantitatively analyzed for wear resistance evaluation and condition / material optimization.

[0057] In this embodiment, the wear rate and wear coefficient of different valve materials or different valve seat materials under the same operating conditions are compared laterally, as shown in Tables 2 and 3. This determines which material combination wears more slowly and is less sensitive to temperature and pressure changes under the same load and slip conditions, thereby completing the evaluation of the material's wear resistance.

[0058] Table 2. Comparison of wear test results for different valve materials and valve seat materials under the same operating conditions.

[0059] Table 3. Comparison of wear test results for different valve materials and valve seat materials under the same operating conditions.

[0060] As shown in Tables 2 and 3, under the same contact pressure of 80 MPa, temperature of 330 °C, and the same atmosphere and motion conditions (operating conditions A–C), combination a has the highest wear rate and wear coefficient, combination b is in the middle, and combination c, which uses nickel-based alloy valves with cobalt-based welded valve seats, has the lowest wear rate. This indicates that under the same load and slip conditions, combination c has the best wear resistance. When the temperature increases from 330 °C to 450 °C (operating conditions A→D, B→E, C→F), the wear rate and wear coefficient of the three material combinations all increase, but combination a has the largest increase, while combination c has the smallest increase. This indicates that the high-grade alloy / welded combination is less sensitive to temperature changes at high temperatures. When the contact pressure is further increased to 100 MPa (operating conditions D→G, E→H, F→I), the wear of the three combinations is further aggravated, but the order of c < b < a is still maintained, and the increase in the wear coefficient of combination c is relatively small. By comparing the wear rate and wear coefficient of different valve / seat material combinations under the same operating conditions, it is possible to clearly determine which material combination wears more slowly and which has lower wear sensitivity under the same load and slip conditions. This allows for the evaluation of the wear resistance of different material options and provides a basis for actual material selection and matching design.

[0061] In this embodiment, the wear measurement module combines wear profile data to observe the maximum wear depth of the contact zone, the width of the wear zone, and whether features such as spalling and steps appear. By comprehensively analyzing quantitative indicators and wear morphology, it identifies the transformation of adhesive wear into failure modes such as fatigue spalling under high temperature, high pressure, or high slip conditions. Through the above multi-condition comparison and multi-material combination analysis, the physical wear properties of the valve material and valve seat material under test can be systematically tested and analyzed, and the obtained wear rate and wear coefficient can be used as the basic parameters for subsequent material selection, life estimation, and simulation modeling.

[0062] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

[0063] In conclusion, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An engine valve wear testing system, characterized in that, include: Sample mounting assembly, coaxially clamping and positioning engine valve and valve seat samples; Mechanical loading components apply dynamic closing impact loads and static combustion peak pressures to the engine valves; The ambient and temperature control components establish high-temperature and combustion conditions at the contact zone between the engine valves and valve seats. The motion control and rotation components drive the engine valves to rotate around their axis during the test; The physical quantity measurement component converts the physical changes generated during the experiment into electrical signals; The wear measurement module unifies multi-source test data to the same time base, calculates wear rate and wear coefficient, and tests and analyzes the physical wear properties of the tested material. The wear measurement module uses impact load, axial static load, and displacement data, combined with the width and average radius of the contact zone between the engine valve and valve seat, to calculate the contact force and equivalent contact area between the engine valve and valve seat, thus obtaining the average contact pressure. Then, using the engine valve rotation speed and angular displacement, combined with the average radius of the contact zone, it calculates the relative sliding speed and circumferential sliding distance between the engine valve and valve seat in the circumferential direction, and estimates the radial micro-slip component. This is then vector-superimposed with the circumferential sliding component to obtain the cumulative relative sliding distance. Next, it uses the wear depth distribution data obtained from the wear profile acquisition device to calculate the wear volume and obtain the wear rate. Finally, based on the average contact pressure, equivalent contact area, cumulative relative sliding distance, and wear volume, the wear coefficient under the corresponding test condition is calculated using a contact condition wear algorithm.

2. The engine valve wear testing system according to claim 1, characterized in that... The process of calling the wear depth distribution data obtained by the wear profile acquisition device, calculating the wear volume, and obtaining the wear rate specifically includes: the wear measurement module calling the wear profile acquisition device to obtain wear depth distribution data at different test time points, performing numerical integration on the wear profile of the contact zone between the engine valve and the valve seat along the circumferential and radial directions, calculating the wear volume corresponding to each measurement time, and combining the time interval between two adjacent profiles to obtain the average wear volume increment, and then calculating the wear rate under the corresponding working condition with time as the independent variable.

3. The engine valve wear testing system according to claim 1, characterized in that... The wear coefficient calculation algorithm for the contact condition includes: multiplying the average contact pressure by the equivalent contact area to obtain the average normal load acting on the contact strip between the engine valve and the valve seat; then combining the cumulative relative slip distance with the average normal load to obtain a normalized reference quantity characterizing the frictional contact; comparing the wear volume obtained by integration through the wear profile acquisition device with the normalized reference quantity; and using the ratio of the wear volume to the average normal load and the relative slip distance as the wear coefficient under the test condition.

4. The engine valve wear testing system according to claim 1, characterized in that, The wear measurement module calculates the wear rate and wear coefficient, which characterize the wear characteristics of valve and valve seat materials, and repeats the test under different operating conditions to form a correspondence between "operating condition parameters - wear rate - wear coefficient". This is used to quantitatively characterize the wear resistance and wear sensitivity of the combination of engine valve and valve seat materials under various typical operating conditions, so as to test and analyze the physical wear properties of the tested materials.

5. The engine valve wear testing system according to claim 1, characterized in that, The sample mounting assembly is fixedly installed in the middle of the test frame, which is a rigid metal frame structure. The sample mounting assembly includes a valve seat fixing seat, a valve guide seat, a valve stem, and a valve clamping head. The valve seat fixing seat has a mounting hole that matches the geometry of the valve seat sample to be tested, for detachably installing valve seat samples with different diameters and seat angles and positioning them axially and radially. The valve guide seat has a guide hole that mates with the valve stem, to ensure that the valve stem remains coaxial with the valve seat axis during reciprocating motion and slow rotation. The valve clamping head is connected to the tail end of the valve stem by a threaded connection or a clamp to achieve quick disassembly and assembly and stable clamping of the engine valve sample.

6. The engine valve wear testing system according to claim 1, characterized in that, The mechanical loading assembly applies dynamic closing impact load and static combustion peak pressure to the engine valves, and includes a first hydraulic loading unit and a second hydraulic loading unit.

7. The engine valve wear testing system according to claim 6, characterized in that, The first hydraulic loading unit is arranged along the engine valve axis and connected to the tail end of the engine valve. It is used to drive the engine valve to reciprocate under a predetermined stroke and speed curve to simulate the opening and closing process of the engine valve and generate an adjustable valve closing impact load. The second hydraulic loading unit is connected to the working surface of the engine valve head through a loading punch and applies an axial static load to the valve head after the engine valve is closed to the position to simulate the contact pressure under the action of the peak combustion pressure.

8. The engine valve wear testing system according to claim 1, characterized in that, The environmental and temperature control assembly establishes high temperature and combustion conditions at the engine valve and valve seat contact zone. It includes an environmental cavity surrounding the engine valve and valve seat contact zone, a gas supply and discharge unit for introducing single or mixed gases into the environmental cavity, an induction heating unit disposed around the engine valve head, and a cooling water jacket disposed around the valve seat. The environmental cavity forms a thermally insulated space for wear testing under predetermined temperature and atmospheric conditions.

9. The engine valve wear testing system according to claim 1, characterized in that, The motion control and rotation component drives the engine valves to rotate around their axis during the test. It includes a valve spring assembly that matches the actual valve train of the engine and a rotation mechanism that drives the valves to rotate slowly around their axis, in order to achieve valve pitch movement and uniform circumferential wear during the test.

10. The engine valve wear testing system according to claim 1, characterized in that, The physical quantity measurement component converts the physical changes generated during the test into electrical signals. It includes a force sensor connected in series with the first hydraulic loading unit and the second hydraulic loading unit, a displacement sensor for measuring valve stroke, a temperature sensor arranged inside or on the surface of the valve head and valve seat, a speed sensor and an angle sensor for detecting the valve rotation state, and a wear profile acquisition device for acquiring the wear morphology of the valve and valve seat contact surfaces.

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