A device and method for mechanical fatigue test of engine block and cylinder head at same frequency

Abstract

This invention provides a device and method for simultaneous mechanical fatigue testing of a machine body and cylinder head, comprising: a machine body to be tested, wherein a cylinder bore is formed on the machine body; a piston, wherein the piston is installed inside the cylinder bore; a cylinder head to be tested, wherein the cylinder head to be tested closes the upper opening of the cylinder bore, and a hydraulic oil chamber is formed between the cylinder head to be tested and the upper end face of the piston; and a connecting rod, wherein one end of the connecting rod is rotatably connected to the piston, and the other end is rotatably connected to the connecting rod journal of a crankshaft, and the main journal of the crankshaft is rotatably connected to the machine body to be tested. The beneficial effects of this invention are: by conducting a single fatigue test, the reliability of both the machine body and the cylinder head to be tested can be tested simultaneously. Compared with the current method of testing different test pieces separately, the testing time can be reduced by half, significantly reducing time, material, and labor costs.

Description

Technical Field

[0001] This invention belongs to the field of engine technology, and in particular relates to a device and method for testing mechanical fatigue of engine block and cylinder head at the same frequency. Background Technology

[0002] The engine block and cylinder head are core components of an engine. As engine power output increases, the mechanical load on the engine block and cylinder head increases significantly. For the engine block, there are two main load-bearing areas: one is the cylinder head, which mainly bears the cylinder head bolt preload and combustion pressure; the other is the transverse diaphragm, which mainly bears the crankshaft bearing load. This load is caused by combustion pressure and inertial force and is transmitted to the engine block diaphragm through the crankshaft connecting rod mechanism. For the cylinder head, the upper end face of the cylinder head mainly bears the cylinder head bolt preload, while the lower end face of the cylinder head mainly bears the combustion pressure.

[0003] In the engine development process, the durability testing and verification of components is an essential and critical step. On the one hand, it provides support for the reliable operation of the entire engine, and on the other hand, it verifies whether the structural strength of the components themselves can meet the design requirements. Therefore, in the forward design process, before the components are provided to the complete engine, component durability assessment and verification must be arranged. Existing fatigue testing devices and methods for engine blocks or cylinder heads are all for conducting fatigue tests on the engine block or cylinder head separately. The following problems exist in the testing process: First, the stiffness matching effect of the connection structure between the engine block and cylinder head cannot be reflected in the overall engine state during component fatigue testing. The introduction of non-standard engine blocks (for cylinder head component fatigue testing) or non-standard cylinder heads (for engine block component fatigue testing) results in a significant deviation between the preload applied to the tested engine block or cylinder head and the overall engine condition, thus altering the stress state of the engine block or cylinder head. Secondly, since the maximum burst pressure and maximum crankshaft bearing load of an engine typically correspond to different crankshaft rotation angles, conventional engine block mechanical fatigue testing equipment cannot simultaneously assess the cylinder head and diaphragm areas in a single test. Thirdly, conducting separate component fatigue tests on the engine block and cylinder head requires a long testing cycle, involves a large number of non-standard parts, and is economically inefficient. Summary of the Invention

[0004] In view of this, the present invention aims to provide a mechanical fatigue testing device and method for the engine block and cylinder head at the same frequency, in order to solve at least one of the above-mentioned technical problems.

[0005] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0006] The first aspect of the present invention provides a mechanical fatigue testing device for engine block and cylinder head at the same frequency, comprising:

[0007] The test body has a cylinder bore.

[0008] Piston, the piston being mounted inside the cylinder bore;

[0009] The cylinder head to be tested closes the upper opening of the cylinder bore, and a hydraulic oil chamber is formed between the cylinder head to be tested and the upper end face of the piston.

[0010] A connecting rod, one end of which is rotatably connected to a piston, and the other end of which is rotatably connected to the connecting rod journal of a crankshaft. The main journal of the crankshaft is rotatably connected to the machine body under test.

[0011] Furthermore, a cylinder head gasket is provided between the cylinder head to be tested and the machine body to be tested;

[0012] The cylinder head to be tested is detachably connected to the body to be tested via connecting bolts.

[0013] Furthermore, a cylinder liner is provided inside the cylinder bore, and the piston is installed on the inner side of the cylinder liner. Multiple annular mounting grooves are opened on the outer side wall of the piston, and sealing rings are provided in the annular mounting grooves.

[0014] Furthermore, a connecting post is fixedly provided on the cylinder head to be tested, and an oil injection hole for the hydraulic oil chamber is opened on the connecting post.

[0015] One end of the oil injection hole is connected to the hydraulic oil chamber, and the other end is connected to the hydraulic oil equipment.

[0016] Furthermore, the connecting rod comes in various models, with different lengths for each model, making it suitable for different specifications of the test body;

[0017] There are various models of crankshafts, and the distance between the main journal and the connecting rod journal varies depending on the model, making them suitable for different specifications of test bodies.

[0018] A second aspect of the present invention provides a method for using the same-frequency mechanical fatigue testing device for engine block and cylinder head as described in the first aspect, comprising the following steps:

[0019] S1. Select the appropriate length of connecting rod and the appropriate model of crankshaft based on the maximum combustion pressure and the maximum load force of crankshaft bearing. Rotate the crankshaft to fix the distance between the piston pin and the main journal, limit the crankshaft radially to prevent crankshaft rotation, and fix the installation angle of the connecting rod journal.

[0020] S2. Use connecting bolts to connect the cylinder head to be tested and the machine body to be tested;

[0021] S3. Inject hydraulic oil into the hydraulic oil chamber at the same pressure as the maximum value of the combustion pressure. The vertical component of the connecting rod is the maximum value of the combustion pressure.

[0022] S4. Repeat S1-S3 until the test body is damaged or the test cylinder head is damaged or the specified number of tests is reached.

[0023] Furthermore, the preload of the connecting bolt in S2 is the preload designed for the engine.

[0024] A third aspect of the present invention provides an electronic device including a processor and a memory communicatively connected to the processor and used to store processor-executable instructions, the processor being used to perform the method described in the first aspect above.

[0025] A fourth aspect of the present invention provides a server including at least one processor and a memory communicatively connected to the processor, the memory storing instructions executable by the at least one processor, the instructions being executed by the processor to cause the at least one processor to perform the method as described in the first aspect.

[0026] The fifth aspect of the present invention provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the method described in the first aspect.

[0027] Compared with the prior art, the mechanical fatigue testing device and method for engine block and cylinder head at the same frequency described in this invention have the following advantages:

[0028] (1) The mechanical fatigue testing device for the body and cylinder head of the present invention can test the reliability of the body and cylinder head under test at the same frequency through a single fatigue test. Compared with the current method of testing different test pieces separately, the testing time can be shortened by half, and the time cost, material cost and manpower cost can be greatly reduced.

[0029] (2) In the mechanical fatigue testing device for engine block and cylinder head of the present invention, during the pre-tightening process of the cylinder head to be tested in the component fatigue test, the engine block to be tested, the cylinder head to be tested and the connecting bolt 1 are components for the whole machine assembly. Therefore, the rigidity of the connecting bolt 1 connection system is consistent with the whole machine, and the pre-tightening force of the connecting bolt 1 in the fatigue test is the pre-tightening force designed for the engine. This ensures that the cylinder head bolt pre-tightening force borne by the engine block and the cylinder head to be tested during the component fatigue test is consistent with the whole machine, and more realistically reflects the stress state of the engine block and cylinder head during the operation of the whole machine. Attached Figure Description

[0030] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0031] Figure 1 This is a schematic cross-sectional view of the device described in an embodiment of the present invention.

[0032] Explanation of reference numerals in the attached figures:

[0033] 1. Cylinder head to be tested; 2. Cylinder head gasket; 3. Engine block to be tested; 4. Piston; 5. Connecting rod; 6. Connecting rod journal; 7. Main journal; 8. Main bearing cap; 9. Connecting bolt two; 10. Cylinder liner; 11. Piston pin; 12. Sealing ring; 13. Connecting bolt one; 14. Connecting column; 15. Oil injection hole. Detailed Implementation

[0034] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0035] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0036] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0037] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0038] Example 1:

[0039] A mechanical fatigue testing device for engine block and cylinder head at the same frequency includes:

[0040] Test body 3, with a cylinder bore on test body 3;

[0041] Piston 4 is installed inside the cylinder bore;

[0042] The cylinder head 1 to be tested closes the upper opening of the cylinder bore, and a hydraulic oil chamber is formed between the cylinder head 1 to be tested and the upper end face of the piston 4.

[0043] Connecting rod 5, one end of which is rotatably connected to piston 4, and the other end of which is rotatably connected to connecting rod journal 6 of crankshaft. The main journal 7 of crankshaft is rotatably connected to the machine body 3 to be tested.

[0044] A cylinder head gasket 2 is provided between the cylinder head 1 to be tested and the machine body 3 to be tested;

[0045] The cylinder head 1 to be tested is detachably connected to the body 3 to be tested via connecting bolt 13.

[0046] A cylinder liner 10 is provided inside the cylinder bore, and a piston 4 is installed on the inner side of the cylinder liner 10. Multiple annular mounting grooves are opened on the outer side wall of the piston 4, and a sealing ring 12 is provided in the annular mounting groove.

[0047] A connecting post 14 is fixed on the cylinder head 1 to be tested, and an oil injection hole 15 is opened on the connecting post 14 to the hydraulic oil chamber;

[0048] One end of the oil injection hole 15 is connected to the hydraulic oil chamber, and the other end is connected to the hydraulic oil equipment.

[0049] There are various models of connecting rod 5, and the length of connecting rod 5 varies with different models, making them suitable for different specifications of the test body 3;

[0050] There are various models of crankshafts, and the distance between the main journal 7 and the connecting rod journal 6 varies depending on the model, making them suitable for different specifications of the test machine body 3.

[0051] A method for conducting mechanical fatigue testing of an engine block and cylinder head at the same frequency includes the following steps:

[0052] S1. Select the appropriate length of connecting rod 5 and the appropriate model of crankshaft based on the maximum value of combustion pressure and the maximum load force of crankshaft bearing. Rotate the crankshaft to fix the distance between the piston 4 pin and the main journal 7, limit the crankshaft radially to prevent crankshaft rotation, and fix the installation angle of connecting rod journal 6.

[0053] S2. Use connecting bolt 13 to connect the cylinder head 1 to the test body 3;

[0054] S3. Inject hydraulic oil into the hydraulic oil chamber at the same pressure as the maximum value of the combustion pressure. The vertical component of the force on the connecting rod 5 is the maximum value of the combustion pressure.

[0055] S4. Repeat S1-S3 until the test body 3 is damaged or the test cylinder head 1 is damaged or the specified number of tests is reached.

[0056] The preload of connecting bolt 13 in S2 is the preload designed for the engine.

[0057] By conducting a single fatigue test, the reliability of both the test body 3 and the test cylinder head 1 can be tested simultaneously. Compared to the current method of testing different test pieces separately, this method can halve the testing time and significantly reduce time, material, and human costs.

[0058] During the pre-tightening process of the cylinder head 1 under test in the component fatigue test, the test body 3, the test cylinder head 1 and the connecting bolt 13 are components used for the assembly of the whole machine. Therefore, the rigidity of the connecting bolt 13 connection system is consistent with that of the whole machine. Moreover, the pre-tightening force of the connecting bolt 13 in the fatigue test is the pre-tightening force designed for the engine. This ensures that the cylinder head bolt pre-tightening force borne by the test body 3 and the test cylinder head 1 during the component fatigue test is consistent with that of the whole machine, and more realistically reflects the stress condition of the body and cylinder head during the operation of the whole machine.

[0059] By using connecting rods 5 of different lengths and the distance from the axis of connecting rod journal 6 to the axis of main journal 7, the installation angle of connecting rod journal 6 during component fatigue testing is determined to satisfy the dynamic relationship of the crankshaft connecting rod 5 mechanism, so as to achieve the goal of maximizing the cylinder loading pressure and crankshaft bearing load. This allows for the simultaneous evaluation of the cylinder head, engine block cylinder head, and diaphragm components through a single component fatigue test.

[0060] By using different models of connecting rod 5 and different models of crankshaft, the installation angle of the connecting rod journal 6 during fatigue testing can be determined, thereby simulating the actual maximum crankshaft bearing load and assessing the reliability of the engine block diaphragm.

[0061] Example 2:

[0062] An electronic device includes a processor and a memory communicatively connected to the processor and used to store processor-executable instructions, the processor being used to execute the method of Embodiment 1 described above.

[0063] Example 3:

[0064] A server includes at least one processor and a memory communicatively connected to the processor, the memory storing instructions executable by the at least one processor, the instructions being executed by the processor to cause the at least one processor to perform the method as described in Embodiment 1.

[0065] Example 4:

[0066] A computer-readable storage medium storing a computer program, wherein the computer program, when executed by a processor, implements the method of Embodiment 1.

[0067] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

[0068] 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. A method for a mechanical fatigue testing device for an engine block and cylinder head operating at the same frequency, characterized in that, A mechanical fatigue testing device for the engine block and cylinder head at the same frequency is adopted, including: The test body (3) has a cylinder hole; Piston (4), the piston (4) is installed inside the cylinder bore; The cylinder head (1) to be tested closes the upper opening of the cylinder bore, and a hydraulic oil chamber is formed between the cylinder head (1) to be tested and the upper end face of the piston (4). Connecting rod (5), one end of which is rotatably connected to piston (4), and the other end is rotatably connected to connecting rod journal (6) of crankshaft, and main journal (7) of crankshaft is rotatably connected to the machine body (3) to be tested; A cylinder head gasket (2) is provided between the cylinder head (1) to be tested and the machine body (3) to be tested; The cylinder head (1) to be tested is detachably connected to the body (3) to be tested via connecting bolt (13); The test method includes the following steps: S1. Select the appropriate length of connecting rod (5) and the appropriate model of crankshaft according to the maximum value of combustion pressure and the maximum load force of crankshaft bearing. Rotate the crankshaft to fix the distance between the piston pin and the main journal (7), limit the crankshaft radially to prevent the crankshaft from rotating, and fix the installation angle of the connecting rod journal (6). S2. Use connecting bolt 1 (13) to connect the cylinder head (1) to be tested to the body (3); S3. Inject hydraulic oil into the hydraulic oil chamber at the same pressure as the maximum value of the combustion pressure. The vertical component of the connecting rod (5) is the maximum value of the combustion pressure. S4. Repeat S1-S3 until the test body (3) is damaged or the test cylinder head (1) is damaged or the specified number of tests is reached.

2. The method for a mechanical fatigue testing device for an engine block and cylinder head at the same frequency according to claim 1, characterized in that: A cylinder liner (10) is provided inside the cylinder bore, and the piston (4) is installed on the inner side of the cylinder liner (10). Multiple annular mounting grooves are opened on the outer side wall of the piston (4), and a sealing ring (12) is provided in the annular mounting groove.

3. The method for a mechanical fatigue testing device for an engine block and cylinder head at the same frequency according to claim 1, characterized in that: A connecting post (14) is fixedly provided on the cylinder head (1) to be tested, and an oil injection hole (15) is opened on the connecting post (14) to the hydraulic oil chamber; One end of the oil injection hole (15) is connected to the hydraulic oil chamber, and the other end is connected to the hydraulic oil equipment.

4. The method for a mechanical fatigue testing device for an engine block and cylinder head at the same frequency according to claim 1, characterized in that: There are various models of the connecting rod (5), and the length of the connecting rod (5) of different models is different, which are suitable for different specifications of the test body (3); There are various models of crankshafts, and the distance between the main journal (7) and the connecting rod journal (6) of different models of crankshafts is different, which is suitable for different specifications of test bodies (3).

5. The method for a mechanical fatigue testing device for an engine block and cylinder head at the same frequency according to claim 1, characterized in that: The preload of the connecting bolt 1 (13) in S2 is the preload designed for the engine.

6. An electronic device, comprising a processor and a memory communicatively connected to the processor and used for storing processor-executable instructions, characterized in that: The processor is used to execute the method described in any one of claims 1-5.

7. A server, characterized in that: The method includes at least one processor and a memory communicatively connected to the processor, the memory storing instructions executable by the at least one processor, the instructions being executed by the processor to cause the at least one processor to perform the method as described in any one of claims 1-5.

8. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, it implements the method described in any one of claims 1-5.

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