Method for replacing valve springs in diesel engines

Abstract

This invention relates to the field of diesel engine technology, and more particularly to a method for replacing valve springs in a diesel engine. The method includes the following steps: S1, positioning the piston plate to the top dead center of the cylinder to be inspected, and connecting the indicator valve on the cylinder head of the cylinder to be inspected to the compressed air pipeline; S2, removing the cylinder head cover, and removing the rocker arm and valve bridge; S3, opening the indicator valve to connect the combustion chamber of the cylinder to be inspected to the compressed air pipeline, allowing compressed air to enter the combustion chamber, maintaining the air pressure in the combustion chamber at a value not less than a set pressure; S4, removing the retaining block and spring seat on the valve, as well as the inner and outer springs on the valve stem; S5, installing new inner and outer springs on the valve stem; S6, reinstalling the retaining block and spring seat; S7, reinstalling the valve bridge, rocker arm, and cover to complete the spring replacement. This invention improves the safety of maintenance, increases replacement efficiency, and reduces maintenance time.

Description

Technical Field

[0001] This invention relates to the field of diesel engine technology, and in particular to a method for replacing valve springs in a diesel engine. Background Technology

[0002] The emergency diesel generator set for passive reactors is a backup power system. Downstream loads mainly include lighting systems, HVAC systems, and systems that provide accident mitigation functions in critical areas. It mainly consists of diesel engines, generators, and control systems.

[0003] A diesel engine, as the power source of a diesel generator set, is a type of power machinery that converts the heat energy from the combustion of fossil fuels into mechanical energy. The high-speed rotating crankshaft of the diesel engine drives the generator rotor to generate electricity. Nuclear power emergency diesel generator sets use high-power (above 5000KW) engines, with a structure of multi-cylinder V-type, large-bore, four-stroke, direct-injection turbocharged diesel engines.

[0004] During overhaul of this type of diesel engine, all cylinder head valve train mechanisms must be inspected, including tappets, rocker arms, rocker arm ball joints, rocker arm shafts, valve bridges, and intake and exhaust valve springs. Among these, the inspection of valve springs is the most crucial. Each cylinder has two exhaust valves and two intake valves; therefore, each cylinder has four external springs and four internal springs. During diesel engine operation, valve springs primarily bear torsional stress and additional loads caused by vibrations in the valve train mechanism. The valve springs open and close the valves according to the valve switching frequency between pre-compression and compression states. In actual operation, valve springs may experience cyclic loads due to manufacturing defects or vibrations caused by airflow, potentially leading to spring breakage or a risk of breakage. When a spring fails, it needs to be replaced; therefore, replacing valve springs is a frequent practical issue encountered during diesel engine overhauls.

[0005] The normal valve spring replacement process requires lifting the cylinder head assembly of each cylinder (the cylinder head assembly weighs about 250KG), disassembling the cylinder head assembly in a special place, replacing the new valve springs and assembling the cylinder head assembly, and then lifting it on site.

[0006] In the above process, multiple cylinder heads were hoisted using lifting equipment; the oil, water, and gas pipelines around the cylinder heads were disassembled and reassembled; and the cylinder heads themselves were disassembled and reassembled. The following problems arose during this process:

[0007] 1. The maintenance work is time-consuming. According to the above maintenance method, replacing the valve springs of multiple cylinder heads will take more than ten days, requiring multiple people to complete the work. The whole process is time-consuming and labor-intensive, which greatly reduces maintenance efficiency and causes the emergency diesel engine to be unavailable for too long.

[0008] 2. Low safety. The cylinder head assembly of a diesel engine weighs approximately 250 kg and requires a crane for hoisting. Repeatedly lifting and lowering this large component poses a significant safety hazard. Furthermore, the disassembly and assembly of the cylinder head assembly to the diesel engine block is complex, which can easily lead to a decline in the quality of fastener tightening, thereby affecting the quality of maintenance.

[0009] Therefore, a method for replacing valve springs in diesel engines is needed to solve the above problems. Summary of the Invention

[0010] The purpose of this invention is to provide a method for replacing valve springs in diesel engines, which can improve the safety of maintenance, increase the efficiency of replacement, and reduce maintenance time.

[0011] To achieve this objective, the present invention adopts the following technical solution:

[0012] The method for replacing valve springs in a diesel engine includes the following steps:

[0013] S1. Position the piston plate to the top dead center of the cylinder to be inspected, and connect the indicator valve on the cylinder head of the cylinder to be inspected to the compressed air pipeline.

[0014] S2. Remove the cylinder head cover and take off the rocker arm and valve bridge;

[0015] S3. Open the indicator valve to connect the combustion chamber of the cylinder to be inspected with the compressed air pipeline, and introduce compressed air into the combustion chamber. The air pressure in the combustion chamber is kept not less than the set air pressure value.

[0016] S4. Remove the retaining block and spring seat on the air valve, as well as the inner and outer springs on the valve stem of the air valve;

[0017] S5. Install new inner and outer springs on the valve stem;

[0018] S6. Reinstall the card block and the spring seat;

[0019] S7. Reinstall the valve bridge, the rocker arm, and the cover to complete the spring replacement.

[0020] Furthermore, in step S1, the diesel engine is rotated by an electric turning device, thereby turning the piston to the top dead center of the compression of the cylinder to be inspected.

[0021] Furthermore, in step S1, an interface converter is installed at the interface of the indicator valve, and the compressed air pipeline is connected to the indicator valve through the interface converter.

[0022] Furthermore, in step S1, a switching valve is connected in series on the compressed air pipeline.

[0023] Further, step S4 includes the following steps:

[0024] S41. Place the support into the injector support;

[0025] S42. By using the pressure plate and the support member to compress the outer spring and the inner spring, the outer spring and the inner spring are separated from the spring seat, and the locking block and the spring seat can be disassembled.

[0026] Furthermore, it also includes S43, striking the spring seat with a wooden hammer to loosen the locking block, and then the locking block can be removed.

[0027] Furthermore, in step S7, after reinstalling the valve bridge, the gap value of the valve bridge is adjusted.

[0028] Furthermore, in step S7, the rocker arm includes an intake rocker arm and an exhaust rocker arm. After reinstalling the intake rocker arm and the exhaust rocker arm, the gap between the intake rocker arm and the exhaust rocker arm is adjusted.

[0029] Furthermore, the compressed air pipeline is connected to an air compressor.

[0030] Furthermore, a pressure gauge is installed on the air compressor.

[0031] The beneficial effects of this invention are:

[0032] This invention provides a method for replacing valve springs in a diesel engine. The piston is positioned at the top dead center of the cylinder to be inspected. The indicator valve on the cylinder head is connected to a compressed air line. The cylinder head cover is removed, and the rocker arm and valve bridge are taken off. The indicator valve is then opened to introduce compressed air into the combustion chamber and pressurized. The retaining block, spring seat, inner spring, and outer spring are then disassembled. After replacing the spring, the retaining block, spring seat, valve bridge, rocker arm, and cover are reinstalled, completing the spring replacement. During this process, the introduction of compressed air into the combustion chamber, and the pressurization of the air within the combustion chamber, ensures that the valve spring does not fall into the cylinder due to gravity after losing its spring compression force. This allows for reliable spring replacement without disassembling the cylinder head assembly. Furthermore, this process eliminates the need for lifting the cylinder head assembly, thereby improving work efficiency, reducing maintenance time, and eliminating the safety hazards associated with lifting operations. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the content of the embodiments of the present invention and these drawings without creative effort.

[0034] Figure 1 This is a flowchart of a method for replacing valve springs in a diesel engine according to the present invention;

[0035] Figure 2 This is a cross-sectional view of the cylinder block in a method for replacing valve springs in a diesel engine according to the present invention.

[0036] In the picture:

[0037] 1. Spring seat; 11. Locking block; 2. Outer spring; 3. Inner spring; 4. Valve stem. Detailed Implementation

[0038] Before explaining any implementation of this application in detail, it should be understood that this application is not limited to its application to the structural details and component arrangements set forth in the following description or shown in the above drawings.

[0039] In this application, the terms "comprising," "including," "having," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0040] In this application, the terms "connection," "combination," "coupling," and "installation" can refer to direct connection, combination, coupling, or installation, or indirect connection, combination, coupling, or installation. For example, a direct connection refers to two parts or components being connected together without the need for an intermediary, while an indirect connection refers to two parts or components each being connected to at least one intermediary, with the connection achieved through the intermediary. Furthermore, "connection" and "coupling" are not limited to physical or mechanical connections or couplings, but can also include electrical connections or couplings.

[0041] In this application, those skilled in the art will understand that relative terms (e.g., “about,” “approximately,” “basically,” etc.) used in conjunction with quantities or conditions are to include the values ​​and have the meaning indicated by the context. For example, such relative terms include at least the degree of error associated with the measurement of a particular value, tolerances associated with the particular value due to manufacturing, assembly, use, etc. Such terms should also be considered as disclosing a range defined by the absolute values ​​of the two endpoints. Relative terms may refer to a certain percentage (e.g., 1%, 5%, 10% or more) of the indicated value. Numerical values ​​not using relative terms should also be disclosed as specific values ​​with tolerances. Furthermore, “basically” when expressing relative angular relationships (e.g., substantially parallel, substantially perpendicular) may refer to a certain degree (e.g., 1 degree, 5 degrees, 10 degrees or more) added to or subtracted from the indicated angle.

[0042] In this application, those skilled in the art will understand that the function performed by a component can be performed by one component, multiple components, one part, or multiple parts. Similarly, the function performed by a part can also be performed by one part, one component, or a combination of multiple parts.

[0043] In this application, the directional terms "upper," "lower," "left," "right," "front," and "rear" are used to describe the orientation and positional relationships shown in the accompanying drawings and should not be construed as limiting the embodiments of this application. Furthermore, in the context, it should be understood that when an element is mentioned as being connected "upper" or "lower" to another element, it can be directly connected to the other element "upper" or "lower," or indirectly connected through an intermediate element. It should also be understood that directional terms such as upper side, lower side, left side, right side, front side, and rear side not only represent positive orientation but can also be understood as lateral orientation. For example, "below" can include directly below, lower left, lower right, lower front, and lower rear.

[0044] During diesel engine maintenance, this method facilitates valve spring replacement while improving maintenance safety, increasing replacement efficiency, and reducing maintenance time. Figures 1-2 As shown, the present invention provides a method for replacing valve springs in a diesel engine. The method for replacing valve springs in a diesel engine includes the following steps:

[0045] S1. Position the piston plate to the top dead center of the cylinder to be inspected, and connect the indicator valve on the cylinder head of the cylinder to be inspected to the compressed air pipeline.

[0046] S2. Remove the cylinder head cover and take off the rocker arm and valve bridge;

[0047] S3. Open the indicator valve to connect the combustion chamber of the cylinder to be inspected with the compressed air pipeline, and introduce compressed air into the combustion chamber. The air pressure in the combustion chamber should be kept at a value not less than the set air pressure value.

[0048] S4. Remove the locking block 11 and spring seat 1 on the air valve, as well as the inner spring 3 and outer spring 2 on the valve stem 4 of the air valve;

[0049] S5. Install the new inner spring 3 and outer spring 2 on the valve stem 4;

[0050] S6, reloading block 11 and spring seat 1;

[0051] S7. Reinstall the valve bridge, rocker arm, and cover to complete the spring replacement.

[0052] During this process, compressed air is introduced into the combustion chamber. After the air is pressurized in the combustion chamber, it ensures that the valve, after losing its spring compression force, will not fall into the cylinder due to gravity. This allows for reliable spring replacement without disassembling the cylinder head assembly. Furthermore, this process eliminates the need for lifting the cylinder head assembly, thus improving work efficiency, reducing maintenance time, and eliminating the safety hazards associated with lifting operations.

[0053] Taking a certain 18-cylinder diesel engine as an example, the lifting and hoisting of 18 cylinder head assemblies can be eliminated, totaling 36 lifting and lowering operations, saving about 4 days of construction time; during maintenance, the disassembly and reassembly of oil, water and gas pipelines of 18 cylinder heads, cylinder head nuts, and the drainage and reinstallation of high-temperature cooling water can be eliminated, saving about 7 days of construction time; in total, 10-11 days of construction time are saved, and labor costs are also reduced.

[0054] Furthermore, in step S1, an electric turning gear is used to drive the diesel engine to rotate, thereby turning the piston to the top dead center of the compression of the cylinder to be inspected. By using an electric turning gear to drive the diesel engine, it is easier to control and at the same time, the labor intensity of workers is reduced.

[0055] Furthermore, in step S1, an interface converter is installed at the interface of the indicator valve, and the compressed air pipeline is connected to the indicator valve through the interface converter. By setting up the interface converter, it is easier to connect the indicator valve to the compressed air pipeline, thereby reducing the difficulty of connecting the compressed air pipeline.

[0056] Furthermore, the compressed air pipeline is connected to an air compressor. The air compressor provides compressed air, which in turn supports the air valves. The air compressor can be moved according to the maintenance location, thus flexibly meeting the needs of on-site maintenance. In other embodiments, a high-pressure air source at the maintenance site can also be used; no further restrictions are imposed here.

[0057] Furthermore, a pressure gauge is installed on the air compressor. By installing a pressure gauge, the output gas pressure of the air compressor can be detected, making it easier for maintenance personnel to understand whether the gas pressure meets the requirements.

[0058] Furthermore, in step S1, a switching valve is connected in series on the compressed air pipeline. By setting the switching valve, when replacing the spring, only by simultaneously opening the indicator valve and the switching valve can the high-pressure gas be supplied. This method helps prevent accidental operation.

[0059] Further, step S4 includes the following steps:

[0060] S41. Place the support into the injector support;

[0061] S42. By using the pressure plate and the support member to compress the outer spring 2 and the inner spring 3, the outer spring 2 and the inner spring 3 are separated from the spring seat 1, and the locking block 11 and the spring seat 1 can be disassembled. Through the cooperation of the support member and the pressure plate, the outer spring 2 and the inner spring 3 can be compressed and separated from the spring seat 1, which facilitates the subsequent removal of the spring seat 1 and the locking block 11.

[0062] Furthermore, step S43 involves striking the spring seat 1 with a wooden hammer to loosen the locking block 11, which can then be removed. Using a wooden hammer avoids rigid collisions with the spring seat 1, preventing deformation or damage to the spring seat 1.

[0063] Furthermore, in step S7, after reinstalling the valve bridge, the clearance value of the valve bridge is adjusted. By adjusting the clearance value of the valve bridge, the correct installation position of the valve bridge can be ensured.

[0064] Furthermore, in step S7, the rocker arm includes an intake rocker arm and an exhaust rocker arm. After reinstalling the intake and exhaust rocker arms, the gap between them is adjusted. This method ensures that the intake and exhaust systems open and close normally according to the designed timing.

[0065] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for replacing valve springs in a diesel engine, characterized in that, Includes the following steps: S1. Position the piston plate to the top dead center of the cylinder to be inspected, and connect the indicator valve on the cylinder head of the cylinder to be inspected to the compressed air pipeline. S2. Remove the cylinder head cover and take off the rocker arm and valve bridge; S3. Open the indicator valve to connect the combustion chamber of the cylinder to be inspected with the compressed air pipeline, and introduce compressed air into the combustion chamber. The air pressure in the combustion chamber is kept not less than the set air pressure value. S4. Remove the latch (11) and spring seat (1) on the air valve, as well as the inner spring (3) and outer spring (2) on the valve stem (4) of the air valve; S5. Install a new inner spring (3) and an outer spring (2) on the valve stem (4); S6. Reinstall the card block (11) and the spring seat (1); S7. Reinstall the valve bridge, the rocker arm, and the cover to complete the spring replacement; Step S4 includes the following steps: S41. Place the support into the injector support; S42. By using the pressure plate and the support member to compress the outer spring (2) and the inner spring (3), the outer spring (2) and the inner spring (3) are separated from the spring seat (1), and the locking block (11) and the spring seat (1) can be disassembled.

2. The method for replacing valve springs in a diesel engine according to claim 1, characterized in that, In step S1, the diesel engine is rotated by an electric turning device, thereby turning the piston to the top dead center of the compression of the cylinder to be inspected.

3. The method for replacing valve springs in a diesel engine according to claim 1, characterized in that, In step S1, an interface converter is installed at the interface of the indicator valve, and the compressed air pipeline is connected to the indicator valve through the interface converter.

4. The method for replacing valve springs in a diesel engine according to claim 1, characterized in that, In step S1, a switching valve is connected in series on the compressed air pipeline.

5. The method for replacing valve springs in a diesel engine according to claim 1, characterized in that, It also includes S43, striking the spring seat (1) with a wooden hammer to loosen the locking block (11), and then the locking block (11) can be removed.

6. The method for replacing valve springs in a diesel engine according to claim 1, characterized in that, In step S7, after reinstalling the valve bridge, the gap value of the valve bridge is adjusted.

7. The method for replacing valve springs in a diesel engine according to claim 1, characterized in that, In step S7, the rocker arm includes an intake rocker arm and an exhaust rocker arm. After reinstalling the intake rocker arm and the exhaust rocker arm, the gap between the intake rocker arm and the exhaust rocker arm is adjusted.

8. The method for replacing valve springs in a diesel engine according to claim 1, characterized in that, The compressed air pipeline is connected to the air compressor.

9. The method for replacing valve springs in a diesel engine according to claim 8, characterized in that, A pressure gauge is installed on the air compressor.

Images