A method for optimizing the sealing of three joint surfaces of an extended-range engine

Abstract

The present invention discloses a method for optimizing the seal at the three-joint surface of a range-extended engine, and relates to the field of automobile design technology. The method includes CAE analysis of a three-dimensional model of the three-joint surface of the range-extended engine under loaded working conditions, including simulation analysis of the mode, sealing surface pressure, bolt stress, slip and opening of the three-dimensional model. If the mode, sealing surface pressure, bolt stress, slip and opening of the three-dimensional model do not meet the third preset standard, the sealing surface structure of the three-dimensional model is optimized until the mode, sealing surface pressure, bolt stress, slip and opening of the three-dimensional model meet the third preset standard. Therefore, in this application, the mode, sealing surface pressure, bolt stress, opening and slip at the three-joint surface are measured and judged based on CAE analysis, so that the range-extended engine can effectively improve the oil leakage problem in the design and test stage to avoid the oil leakage problem during its working process.

Description

Technical Field

[0001] The invention relates to the technical field of automobile design, and in particular to a method for optimizing the sealing of three joint surfaces of an extended-range engine. Background Art

[0002] A range extender is a device that uses other energy sources (such as gasoline) to replenish electricity when the car battery is exhausted. Traditionally, a range extender refers to a combination of an engine and a generator, while a range extender engine includes an engine block, a cylinder head, and a front cover, which form a three-sided sealed structure when assembled.

[0003] Due to the particularity of the REV model's operating conditions, the range extender is started more frequently than traditional fuel vehicles (traditional fuel vehicles only need to be started when driving / idling). Therefore, the engine body will be subjected to a large impact load during the repeated and frequent starting of the range extender. At the same time, the starting load will have a significant impact on the sealing of the three-joint surface of the engine body. In severe cases, it will also cause the lubrication system to deteriorate, causing cylinder pulling and bearing locking. Although structural improvements can be used in related technologies to alleviate such problems, there is no complete three-joint surface optimization method in the industry to solve the problem of easy oil leakage at the three-joint surface. Summary of the invention

[0004] In view of the defects existing in the prior art, the purpose of the present invention is to provide a sealing optimization method at the three-joint surfaces of an extended-range engine, so as to solve the problem of oil leakage at the three-joint surfaces in the related art.

[0005] In order to achieve the above objectives, the technical solution adopted by the present invention is: to provide a method for optimizing the sealing of the three joint surfaces of an extended-range engine, comprising the following steps:

[0006] Step S1: performing a timing cover modal analysis on the three-dimensional model of the extended-range engine three-joint surface under the loaded working condition and obtaining a first-order modal calculation value of the assembly; if the first-order modal calculation value of the assembly does not meet a first preset standard, performing a structural modal optimization on the three-joint surface of the extended-range engine until the first-order modal calculation value of the assembly of the three-dimensional model meets the first preset standard;

[0007] Step S2: performing surface pressure simulation analysis on the sealing surface of the three-dimensional model obtained in step S1, and confirming whether there is an area with zero surface pressure on the sealing surface. If there is an area with zero surface pressure on the sealing surface, structural optimization is performed on the three-combination surface of the programmed engine until the surface pressure of the sealing surface of the three-dimensional model is greater than zero;

[0008] Step S3: performing a tensile stress simulation analysis on the bolt fastening surface of the three-dimensional model obtained in step S2, and if the tensile stress at the bolt fastening surface does not meet the second preset standard, optimizing the bolt mechanical distribution on the three-combination surface of the programmed engine until the tensile stress at the bolt fastening surface meets the second preset standard;

[0009] Step S4: Simulate and analyze the slip and opening of the three-dimensional model obtained in step S3. If the slip and opening of the three-dimensional model do not meet the third preset standard, optimize the sealing surface structure of the three-joint surfaces of the programmed engine until the slip and opening of the three-joint surfaces of the programmed engine meet the third preset standard.

[0010] In some embodiments, the third preset standard includes: the slip amount and the opening amount should both be less than 8 μm.

[0011] In some embodiments, the sealing surface structure optimization of the three-dimensional model is performed until the slip amount and the opening amount of the three-dimensional model meet the third preset standard, including:

[0012] The glue storage space at the joint surface between the cylinder head and the front cover shell of the three-dimensional model is increased.

[0013] In some embodiments, the step of increasing the glue storage space at the joint surface between the cylinder head and the front cover of the three-dimensional model includes:

[0014] An 8° chamfered structure is provided at the joint surface between the cylinder head and the front cover shell.

[0015] In some embodiments, the sealing surface structure optimization of the three-dimensional model is performed until the slip amount and the opening amount of the three-dimensional model meet the third preset standard, including:

[0016] At least two sealing grooves are arranged at the three-joint surfaces of the cylinder body, the cylinder head and the front cover shell of the three-dimensional model.

[0017] In some embodiments, the sealing surface structure optimization of the three-dimensional model is performed until the slip amount and the opening amount of the three-dimensional model meet the third preset standard, and further includes:

[0018] Fish scale-like knife patterns are processed on the three-dimensional model's three-dimensional joint surfaces of the cylinder body, the cylinder head and the front cover.

[0019] In some embodiments, the sealing surface structure optimization of the three-dimensional model is performed until the slip amount and the opening amount of the three-dimensional model meet the third preset standard, and further includes:

[0020] A reinforcing rib is added to the air intake side of the cylinder block of the three-dimensional model.

[0021] In some embodiments, the second preset standard includes:

[0022] The tensile stress at the bolt fastening surface should be less than 200Mpa.

[0023] In some embodiments, the three-dimensional model performs bolt mechanical distribution optimization until the tensile stress at the bolt fastening surface meets the second preset standard, including:

[0024] An independent suspension bracket is arranged on the cylinder body of the three-dimensional model.

[0025] In some embodiments, the first preset standard includes: the calculated value of the first-order modal of the assembly should be greater than 500 Hz.

[0026] Compared with the prior art, the advantages of the present invention are:

[0027] (1) In the optimization method of the three-joint surfaces of the range-extended engine in the present invention, the applicant found that the tendency of the front cover to slide relative to the cylinder block and the cylinder head (i.e., the slip amount) and the tendency of the front cover to separate relative to the cylinder block and the cylinder head (i.e., the opening amount) have a great influence on the oil leakage problem. Therefore, in this application, the opening amount and the slip amount at the three-joint surfaces are measured and judged based on CAE analysis, so that the oil leakage problem of the range-extended engine can be effectively improved in the design and test stage to avoid the occurrence of oil leakage during its operation.

[0028] (2) The applicant of the present invention has found that the timing chain cover of the engine generally adopts an integrated suspension installation. During the operation of the engine, the timing chain cover is affected by the impact force of the suspension, and is easily pulled and deformed, which affects the sealing of the three-joint surface and causes oil leakage on the three-joint surface. Therefore, in this application, for the structure that does not meet the preset standards in the analysis stage, an independent suspension installation structure can be used to solve its oil leakage problem.

[0029] (3) In the optimization method of the three-joint surface of the range-extended engine in the present invention, the chamfer can be increased to increase the glue storage space in the sealing area to enhance the sealing effect.

[0030] (4) In the optimization method of the three-joint surface of the range-extended engine in the present invention, an umbrella-shaped sealing groove is used for the area prone to oil leakage so that the sealant can be fully filled in the area.

[0031] (5) The sealing surface in the optimization method of the three joint surfaces of the range-extended engine in the present invention can be processed with fish-scale pattern knife patterns to increase the adhesion of the glue on the joint surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0033] Figure 1 It is a flow chart of a method for optimizing the sealing at three joint surfaces of a range-extended engine in an embodiment of the present invention;

[0034] Figure 2 It is a partial cross-sectional view of the range-extended engine in the embodiment of the present invention as viewed from the side;

[0035] Figure 3 In the embodiment of the present invention Figure 2 Partial cross-sectional view at C in the middle;

[0036] Figure 4 It is a front view of the assembly model in the embodiment of the present invention;

[0037] Figure 5 It is a front view of the assembly model in the embodiment of the present invention when the front cover is installed.

[0038] In the figure: 1. cylinder head; 2. front cover; 3. cylinder body; 4. intake side; 5. exhaust side. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0040] The embodiments of the present invention are further described in detail below with reference to the accompanying drawings. Figure 1 As shown, the present application provides a method for optimizing the sealing of the three joint surfaces of a range-extended engine to solve the problem that the three joint surfaces of the range-extended engine are prone to oil leakage during driving, which includes the following steps:

[0041] S1. The model is established and bolt torque loading and working condition loading are performed.

[0042] Specifically, the input assembly model includes a cylinder head 1, a cylinder block 3 and a front cover 2. The cylinder head 1 is made of material AC4B, the cylinder block 3 is made of material HT250, and the front cover 2 is made of material ADC12.

[0043] Furthermore, the working load selection is 8KPH±11g front and rear collision, vertical up and down loading ±5g / lateral left and right loading ±3g. Bolt torque loading selection: M8 (23±2N·m), M10 (50±5N·m).

[0044] S2. Performing a timing cover modal analysis on the three-dimensional model of the extended-range engine three-joint surface under loaded working condition and obtaining a first-order modal calculation value of the assembly; if the first-order modal calculation value of the assembly does not meet the first preset standard, performing structural modal optimization on the three-dimensional model until the first-order modal calculation value of the assembly meets the first preset standard;

[0045] Specifically, the present application provides a preset standard determined through multiple tests, wherein a first preset standard for the first-order modal calculation value at the three-joint surface of the assembly model includes: the first-order modal calculation value should be greater than 500 Hz.

[0046] S3. Performing surface pressure simulation analysis on the sealing surface of the three-dimensional model obtained in the previous step that meets the first preset standard, and confirming whether there is an area with zero surface pressure on the sealing surface. If there is an area with zero surface pressure on the sealing surface, optimizing the structure of the three-dimensional model until the surface pressure of the sealing surface is greater than zero;

[0047] Preferably, the surface pressure at the glue storage tank positions of the three joint surfaces needs to be uniform, and the surface pressure should be greater than 0 MPa.

[0048] S4. Performing a tensile stress simulation analysis on the bolt fastening surface of the three-dimensional model whose sealing surface meets the requirements obtained in the previous step; if the tensile stress at the bolt fastening surface does not meet the second preset standard, optimizing the bolt mechanical distribution of the three-dimensional model until the tensile stress at the bolt fastening surface meets the second preset standard;

[0049] Preferably, the second preset standard includes: the tensile stress at the three-joint surface bolt fastening surface should be less than 200 MPa.

[0050] It is understandable that the three-joint surface of conventional engines is generally installed with an integrated suspension. During the operation of the engine, the timing chain cover is affected by the impact force of the suspension, and is easily pulled and deformed, which affects the sealing of the three-joint surface and causes oil leakage on the three-joint surface. In this application, the optimization of the mechanical distribution of the bolts can use an independent suspension bracket to improve the tensile stress at the bolt fastening surface.

[0051] In some embodiments, the optimization of the mechanical distribution of bolts further includes: adding reinforcing ribs to the intake side 4 of the cylinder block 3 of the three-dimensional model so that the tensile stress at the bolt fastening surface meets the second preset standard.

[0052] S5. Perform simulation analysis on the slip and opening amount of the three-dimensional model obtained in the previous step that meets the second preset standard. If the slip and opening amount of the three-dimensional model do not meet the third preset standard, optimize the sealing surface structure of the three-dimensional model until the slip and opening amount of the three-dimensional model meet the third preset standard.

[0053] Preferably, the third preset standard includes: the opening amount at the three joint surfaces should be less than 8 μm, and the slip amount at the three joint surfaces should be less than 8 μm.

[0054] It is understandable that if Figure 2 As shown, the sliding amount of the front cover 2 refers to the direction A in the figure and the two directions perpendicular to the paper surface, that is, the sliding variable of the front cover 2 relative to the cylinder head 1 and the cylinder body 3. The above-mentioned opening amount refers to Figure 2 The variable value in the B direction, that is, the direction in which the front cover 2 separates from or approaches the cylinder head 1 and the cylinder body 3. It should be noted that both the opening amount and the slip amount are microscopic changes, but it is these microscopic changes that may cause oil leakage in the engine.

[0055] Preferably, the sealing surface structure optimization includes: adding a chamfer structure to the joint surface between the cylinder head 1 and the front cover shell 2 to increase the glue storage space in the sealing area. Specifically, the angle of the chamfer structure is 8°. Further, the structural improvement can be to use a social umbrella-shaped sealing groove at the three joint surfaces of the front cover shell 2 to fill the sealant. At the same time, an additional layer of groove can be set on the outside of the umbrella-shaped sealing groove to form a double sealing insurance. Both of the above are achieved by improving the use effect of the sealant.

[0056] Furthermore, the sealing surface structure can be optimized by providing fish-scale-like processing knife patterns at the three joint surfaces of the assembly model to increase the adhesion of the glue on the joint surfaces.

[0057] S6. According to the results of the analysis and optimization, a physical engine is manufactured and a road test is carried out (the general road test distance should be about 30km).

[0058] It is worth noting that the above-mentioned optimization of bolt mechanical distribution and sealing surface structure is not limited to the above-mentioned specific optimization methods, and users can use them flexibly according to their needs.

[0059] In some embodiments, a cylinder gasket is also provided at the three joint surfaces. The cylinder head 1, the cylinder gasket, the cylinder block 3 and the front cover shell 2 are assembled with each other and enclosed at the end surface to form a glue storage tank. The width of the glue storage tank at the joint of the three end surfaces of the cylinder head 1, the cylinder block 3 and the front cover shell 2 is greater than the width at the joint of the two end surfaces of the cylinder head 1 and the front cover shell 2 or the cylinder block 3 and the front cover shell 2. From the joint of the three end surfaces of the cylinder head 1, the cylinder block 3 and the front cover shell 2 to the joint of the two end surfaces of the cylinder head 1 and the front cover shell 2 or the cylinder block 3 and the front cover shell 2, the width of the glue storage tank gradually narrows. This can prevent the glue storage tank from suddenly narrowing and causing stress concentration and fracture. The extension length of the glue storage tank from the joint of the three end surfaces of the cylinder head 1, the cylinder block 3 and the front cover shell 2 to the joint of the two end surfaces of the cylinder head 1 and the front cover shell 2 or the joint of the two end surfaces of the cylinder block 3 and the front cover shell 2 is 15-20 mm. The glue storage tank is a three-section structure, that is, the end close to the sealing surface is an arc, and the middle section is a plane or an inclined surface. When the middle section is an inclined surface, preferably, the inclination angle of the inclined surface is 1-1.5°. The end of the glue storage tank is chamfered. The three-section structure can help the sealant to fully fill the area after being squeezed, thereby forming a complete and dense rubber strip.

[0060] It is worth noting that the present application performs optimization analysis in the above order, and the optimization and improvement method thereof is from simple to complex, step by step, so as to avoid unnecessary investment by the staff in the optimization design.

[0061] In other embodiments, a sealing hole for injecting sealant is provided at the junction of the three joint surfaces of the engine cylinder block. After the sealant is injected into the sealing hole, the bonding area between the glue and the metal surface is increased at the intersection of the three joint surfaces of the cylinder block, effectively increasing the sealing ability of the glue. Preferably, the sealing hole is composed of grooves provided on each surface of the three joint surfaces of the engine cylinder block, that is, the sealing hole is provided in the T-shaped area where the three joint surfaces are combined; preferably, the sealing hole is a through hole provided at the junction of the three joint surfaces of the engine cylinder block. Preferably, the sealing hole is a cylindrical hole, and a cylindrical hollow structure is processed when the three joint surfaces are not coated with glue, and then the hollow structure is filled with glue. The effective area of ​​the cylinder is larger than that of other shapes, so the sealing effect is better and it is more convenient to process; or the corresponding position is calculated and the cylindrical hollow body is cast during casting to save processing costs. When the three joint surfaces of the engine cylinder block are sealed, in addition to the joint surfaces being coated with glue, the sealing hole is also filled with glue, which is conducive to sealing. The sealing hole is a cylindrical hole, which not only increases the bonding area of ​​the glue, but also effectively fills the dislocation gap between the three bonding surfaces due to heat. The diameter of the sealing hole is preferably less than 2mm. During processing, a drill with a smaller diameter can be used to drill into the intersection of the three bonding surfaces to form a hollow cylindrical structure. The exact position of the three bonding surfaces can also be selected by casting to achieve a cylindrical hollow structure during casting. When the three bonding surfaces of the engine cylinder block are sealed, glue is applied to the bonding surfaces and the sealing holes are also filled with sealant. When applying glue, attention should be paid to the order of gluing. The surfaces of each bonding surface should be applied with glue first, and attention should be paid to uniformity and surface cleanliness, and then the sealant should be applied to the small cylindrical sealing hole. Control the surface finish of the hole, and the surface finish should not be too poor; the surface roughness of the casting should also meet the requirements to ensure that the sealant is fully fitted with the metal surface and to achieve our reliable sealing performance. Whether in terms of processing or casting, it can be achieved through simple and feasible methods, and the cost is well controlled.

[0062] like Figure 2 and Figure 3 As shown, the present application also provides an optimized structure at the three joint surfaces of the range-extended engine, which includes: a cylinder head 1, a front cover 2 and a cylinder block 3; wherein,

[0063] A chamfered structure is added to the joint surface between the cylinder head 1 and the front cover 2 to increase the glue storage space in the sealing area. Specifically, the angle of the chamfered structure is 8°. Further, the structural improvement can be made by filling the sealant with a social umbrella-shaped sealing groove at the three joint surfaces of the front cover 2. At the same time, an additional groove can be set on the outside of the umbrella-shaped sealing groove to form a double sealing insurance. Both of the above are achieved by improving the use effect of the sealant.

[0064] Furthermore, the structural improvement can also be achieved by providing fish-scale-like processing knife patterns at the three joint surfaces of the assembly model to increase the adhesion of the glue on the joint surfaces.

[0065] like Figure 4 and Figure 5 As shown, it is understandable that the three-joint surface of conventional engines is generally installed with an integrated suspension. During the operation of the engine, the timing chain cover is affected by the impact of the suspension and is easily pulled and deformed, which affects the sealing of the three-joint surface and causes oil leakage on the three-joint surface. In this application, an independent suspension bracket can be used. Figure 3 An independent suspension bracket can be installed at the cylinder body 3.

[0066] Preferably, the present application may add reinforcing ribs on the air intake side of the cylinder body 3 .

[0067] In some embodiments, a cylinder gasket is also provided at the three joint surfaces. The cylinder head 1, the cylinder gasket, the cylinder block 3 and the front cover shell 2 are assembled with each other and enclosed at the end surface to form a glue storage tank. The width of the glue storage tank at the joint of the three end surfaces of the cylinder head 1, the cylinder block 3 and the front cover shell 2 is greater than the width at the joint of the two end surfaces of the cylinder head 1 and the front cover shell 2 or the cylinder block 3 and the front cover shell 2. From the joint of the three end surfaces of the cylinder head 1, the cylinder block 3 and the front cover shell 2 to the joint of the two end surfaces of the cylinder head 1 and the front cover shell 2 or the cylinder block 3 and the front cover shell 2, the width of the glue storage tank gradually narrows. This can prevent the glue storage tank from suddenly narrowing and causing stress concentration and fracture. The extension length of the glue storage tank from the joint of the three end surfaces of the cylinder head 1, the cylinder block 3 and the front cover shell 2 to the joint of the two end surfaces of the cylinder head 1 and the front cover shell 2 or the joint of the two end surfaces of the cylinder block 3 and the front cover shell 2 is 15-20 mm. The glue storage tank is a three-section structure, that is, the end close to the sealing surface is an arc, and the middle section is a plane or an inclined surface. When the middle section is an inclined surface, preferably, the inclination angle of the inclined surface is 1-1.5°. The end of the glue storage tank is chamfered. The three-section structure can help the sealant to fully fill the area after being squeezed, thereby forming a complete and dense rubber strip.

[0068] In some embodiments, a sealing hole for injecting sealant is provided at the junction of the three joint surfaces of the engine cylinder block. After injecting sealant into the sealing hole, the bonding area between the glue and the metal surface at the intersection of the three joint surfaces of the cylinder block is increased, and the sealing ability of the glue is effectively increased. Preferably, the sealing hole is composed of grooves provided on each surface of the three joint surfaces of the engine cylinder block, that is, the sealing hole is provided at the T-shaped area where the three joint surfaces are combined; preferably, the sealing hole is a through hole provided at the junction of the three joint surfaces of the engine cylinder block. Preferably, the sealing hole is a cylindrical hole, and a cylindrical hollow structure is processed when the three joint surfaces are not coated with glue, and then the hollow structure is filled with glue. The effective area of ​​the cylinder is larger than that of other shapes, so the sealing effect is better and it is more convenient to process; or the corresponding position is calculated and the cylindrical hollow body is cast during casting, saving processing costs. When the three joint surfaces of the engine cylinder block are sealed, in addition to the joint surfaces being coated with glue, the sealing hole is also filled with glue, which is conducive to sealing. The sealing hole is a cylindrical hole, which not only increases the bonding area of ​​the glue, but also effectively fills the misaligned gaps between the three joint surfaces due to heat. The diameter of the sealing hole is preferably less than 2mm. During processing, a drill with a smaller diameter can be used to drill into the intersection of the three joint surfaces to form a hollow cylindrical structure. The exact position of the three joint surfaces can also be selected by casting to achieve a cylindrical hollow structure during casting. When the three joint surfaces of the engine cylinder block are sealed, glue is applied to the joint surfaces and the sealing holes are also filled with sealant. When applying glue, attention should be paid to the order of gluing. The surfaces of each joint surface should be applied with glue first, and attention should be paid to being even and paying attention to the surface cleanliness, and then the sealant should be applied to the small cylindrical sealing hole. Control the surface finish of the hole, and the surface finish should not be too poor; the surface roughness of the casting must also meet the requirements to ensure that the sealant is fully fitted with the metal surface and to achieve our reliable sealing performance. Both processing and casting can be achieved through simple and feasible methods, and the cost is well controlled.

[0069] The present application also provides a design embodiment of a three-joint surface of a range-extended engine, which includes:

[0070] Step 1: Establish the assembly model (including cylinder head, cylinder block, timing chain cover, and suspension bracket), where the model materials are: cylinder head (AC4B), cylinder block (HT250), and timing chain cover (ADC12).

[0071] Step 2: Torque and working condition loading.

[0072] The assembly model is loaded with bolt torque: M8 (23±2N·m), M10 (50±5N·m).

[0073] Calculate the working condition loading for the assembly model: select some working conditions according to the suspension 28 working conditions (mainly select 8KPH±11g front and rear collision, vertical up and down loading ±5g / lateral left and right loading ±3g).

[0074] Step 3: Perform CAE stress analysis, judgment and optimization on the assembly model.

[0075] The results show that: the calculated value of the first-order modal of the assembly is 944 Hz (standard > 500 Hz), the calculated value of the sealing surface opening is 0.8-1.5 μm on the intake side 4 and 0.7-1.2 μm on the exhaust side 5; the larger values ​​of the sealing surface slip are concentrated near the bolt holes, and the slip at the three-joint surface is 4.8 μm.

[0076] From the above data, it can be seen that the above data do not meet the preset standards: the first-order modal calculation value at the three-joint surface should be greater than 500Hz, the opening amount at the three-joint surface should be less than 8μm, and the slip amount at the three-joint surface should be less than 8μm. Therefore, the assembly model at the three-joint surface of the engine needs to be optimized (i.e., structural improvement).

[0077] The structural improvement includes: adding a chamfer structure to the joint surface between the cylinder head 1 and the front cover 2 to increase the glue storage space in the sealing area. Specifically, the angle of the chamfer structure is 8°. Further, the structural improvement can be to fill the sealant with a social umbrella-shaped sealing groove at the three joint surfaces of the front cover 2. At the same time, an additional groove can be set on the outside of the umbrella-shaped sealing groove to form a double seal insurance.

[0078] Optionally, the structural improvement may also be achieved by providing fish-scale-like processing knife patterns at the three joint surfaces of the assembly model to increase the adhesion of the glue on the joint surfaces.

[0079] It is understandable that the three-joint surface of conventional engines is generally installed with an integrated suspension. During the operation of the engine, the timing chain cover is affected by the impact force of the suspension, and is easily pulled and deformed, which affects the sealing of the three-joint surface and causes oil leakage on the three-joint surface. In this application, an independent suspension bracket can be used.

[0080] After the above improvements, CAE analysis was performed again, and the analysis is summarized in the following table:

[0081]

[0082] The calculated value of the first-order modal of the assembly is 867Hz (>500Hz); the opening amount of the intake side 4 is ≤1.3μm, and the sealing groove on the exhaust side is ≤0.3μm; the larger slip value is concentrated near the bolt hole, and the slip at the three-joint surface is <3.2μm. Among them, the modal of the QT450 independent suspension bracket meets the requirements (>500Hz). The slip of the three-joint surface is improved compared with the original state. The tensile stress at the three-joint surface of the timing chain cover of the independent suspension bracket is reduced, the overall deformation is small, and the sealing is good. The surface pressure at the three-joint surface should be greater than 0MPa, and the compressive stress at the three-joint surface is less than 220MPa.

[0083] After the above simulation test is completely passed, the vehicle endurance road test (30K km) can be arranged to verify that there is no oil leakage problem on the three joint surfaces.

[0084] In summary, in the optimization method of the three-joint surface of the extended-range engine in the present invention, the applicant found that the tendency of the front cover shell to slide relative to the cylinder block and the cylinder head (i.e., the amount of slippage) and the tendency of the front cover shell to separate relative to the cylinder block and the cylinder head (i.e., the amount of opening) have a greater impact on the oil leakage problem. Therefore, in this application, the amount of opening and the amount of slippage at the three-joint surface are measured and judged based on CAE analysis, so that the extended-range engine can effectively improve the oil leakage problem in the design and test stage to avoid the oil leakage problem during its operation. The applicant in the present invention found that the engine generally adopts an integrated suspension to install the engine. During the operation, the timing chain cover is affected by the impact force of the suspension, which is very easy to be pulled and deformed, affecting the sealing of the three-joint surface, resulting in oil leakage problems on the three-joint surface. Therefore, in this application, for the structure that does not meet the preset standards in the analysis stage, an independent suspension installation structure can be used to solve its oil leakage problem. In the optimization method of the three-joint surface of the extended-range engine in the present invention, the method of increasing chamfers can be used to increase the glue storage space in the sealing area to enhance the sealing effect. In the optimization method of the three joint surfaces of the range-extending engine in the present invention, an umbrella-shaped sealing groove is used for the area prone to oil leakage so that the sealant can be fully filled in the area. In the optimization method of the three joint surfaces of the range-extending engine in the present invention, the sealing surface can be processed with fish scale pattern knife pattern to increase the adhesion of the glue on the joint surface.

[0085] In the description of the present application, it should be noted that the terms "upper", "lower", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0086] It should be noted that, in this application, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0087] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A method for optimizing the sealing of three joint surfaces of an extended-range engine, characterized in that: The following steps are involved: Step S1: performing a timing cover modal analysis on the three-dimensional model of the extended-range engine three-joint surface under the loaded working condition and obtaining a first-order modal calculation value of the assembly; if the first-order modal calculation value of the assembly does not meet a first preset standard, performing a structural modal optimization on the three-joint surface of the extended-range engine until the first-order modal calculation value of the assembly of the three-dimensional model meets the first preset standard; Step S2: performing surface pressure simulation analysis on the sealing surface of the three-dimensional model obtained in step S1, and confirming whether there is an area with zero surface pressure on the sealing surface; if there is an area with zero surface pressure on the sealing surface, performing structural optimization on the three-combination surface of the range-extended engine until the surface pressure of the sealing surface of the three-dimensional model is greater than zero; Step S3: performing a tensile stress simulation analysis on the bolt fastening surface of the three-dimensional model obtained in step S2, and if the tensile stress at the bolt fastening surface does not meet the second preset standard, optimizing the bolt mechanical distribution on the three-combination surface of the range-extended engine until the tensile stress at the bolt fastening surface meets the second preset standard; Step S4: performing simulation analysis on the slip and opening of the three-dimensional model obtained in step S3; if the slip and opening of the three-dimensional model do not meet the third preset standard, performing sealing surface structure optimization on the three-joint surfaces of the extended-range engine until the slip and opening of the three-joint surfaces of the extended-range engine meet the third preset standard.

2. The method for optimizing the sealing of the three joint surfaces of the range-extended engine according to claim 1, characterized in that: The third preset standard includes: the slip amount and the opening amount should both be less than 8 μm.

3. The method for optimizing the sealing of the three joint surfaces of the range-extended engine according to claim 1, characterized in that: The step of optimizing the sealing surface structure of the three-joint surfaces of the range-extended engine until the slippage amount and the opening amount of the three-joint surfaces of the range-extended engine meet the third preset standard includes: The glue storage space at the joint surface between the cylinder head (1) and the front cover (2) of the range-extended engine is increased.

4. The method for optimizing the sealing of the three joint surfaces of the range-extended engine according to claim 3, characterized in that: The method of increasing the glue storage space at the joint surface between the cylinder head (1) and the front cover (2) of the range-extended engine comprises: An 8° chamfered structure is provided at the joint surface between the cylinder head (1) and the front cover shell (2).

5. The method for optimizing the sealing of the three joint surfaces of the range-extended engine according to claim 1, characterized in that: The step of optimizing the sealing surface structure of the three-joint surfaces of the range-extended engine until the slippage amount and the opening amount of the three-joint surfaces of the range-extended engine meet the third preset standard includes: At least two sealing grooves are arranged at the three joint surfaces of the cylinder body (3), the cylinder head (1) and the front cover (2) of the range-extended engine.

6. The method for optimizing the sealing of the three joint surfaces of the range-extended engine according to claim 5, characterized in that: The method further comprises: optimizing the sealing surface structure of the three joint surfaces of the range-extended engine until the slip amount and the opening amount at the three joint surfaces of the range-extended engine meet the third preset standard; Fish-scale-like knife patterns are processed on the three-dimensional model's three-dimensional joint surfaces of the cylinder body (3), the cylinder head (1) and the front cover (2).

7. The method for optimizing the sealing of the three joint surfaces of the range-extended engine according to claim 1, characterized in that: The step of optimizing the sealing surface structure of the three-dimensional model until the slip amount and the opening amount of the three-dimensional model meet the third preset standard includes: A reinforcing rib is added to the air intake side (4) of the cylinder body (3) of the three-dimensional model.

8. The method for optimizing the sealing of the three joint surfaces of the range-extended engine according to claim 1, characterized in that: The second preset standard includes: The tensile stress at the bolt fastening surface should be less than 200Mpa.

9. The method for optimizing the sealing of the three joint surfaces of the range-extended engine according to claim 1, characterized in that: The three-dimensional model performs bolt mechanical distribution optimization until the tensile stress at the bolt fastening surface meets the second preset standard, including: An independent suspension bracket is arranged on the cylinder body (3) of the three-dimensional model.

10. The method for optimizing the sealing of the three joint surfaces of the range-extended engine according to claim 1, characterized in that: The first preset standard includes: the first-order modal calculation value of the assembly should be greater than 500 Hz.

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