A sealing structure of an injector and an engine

Abstract

The present invention discloses a sealing structure of an injector, which includes an injector, a cylinder head, and a cylinder head cover. A fuel injector hole is provided on the top surface of the cylinder head, the injector is installed in the fuel injector hole, and the cylinder head cover is installed on the top surface of the cylinder head. It further includes a bushing and a second O-ring. A bushing is provided between the fuel injector hole and the injector, and the inner side of the bushing is in clearance fit with the injector. The upper end of the fuel injector hole is reamed to form a counterbore at the upper end of the fuel injector hole. The upper end of the bushing protrudes above the top surface of the cylinder head, and the cylinder head cover is provided with a corresponding relief groove to avoid the bushing body protruding above the top surface of the cylinder head. The counterbore and the bushing cooperate to form a second sealing groove, and the second sealing ring is installed in the second sealing groove. The present invention has the advantages of good sealing performance, stable structure, convenient disassembly and assembly, etc.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel injector sealing, and particularly to a sealing structure of a fuel injector and an engine. Background Art

[0002] Effective sealing of diesel engine oil is one of the prerequisites for ensuring its efficient operation. When using lubricating oil, sealing requirements must be considered. Currently, the commonly used sealing methods include O-rings, sealing gaskets, and interference fits.

[0003] The cylinder head cover is a cover for sealing the valve train on the engine cylinder head. When the engine is working, its inner cavity is filled with oil-gas containing atomized lubricating oil and liquid lubricating oil splashed by moving parts. These lubricating oils and oil-gas must be completely sealed. Most existing cylinder head covers are a ring-shaped flat belt. Generally, sealing glue is applied on the sealing belt, or non-asbestos flat gaskets are used, or sealing rubber strips, paper gaskets and other sealing forms are used, but it is difficult to ensure the sealing effect. During the normal rotation of the lubricating camshaft, oil leakage will occur near the fuel injector of the cylinder head cover.

[0004] Ordinary cylinder head cover paper gaskets are cheap and easy to use. However, when it is close to the exhaust side and is affected by heat radiation, or when the cylinder head cover bolts are used to support the muffler or post-treatment above, it is prone to oil leakage due to heat or up and down vibration.

[0005] The existing patent document CN205064158U discloses a transverse cavity type fuel injection structure for a diesel engine, in which an annular groove is provided on the outer wall of the middle part of the fuel injector body, and a sealing ring is nested in the annular groove, and the sealing ring is elastically pressed against the inner side wall of the fuel injector hole. Although this sealing structure can prevent engine oil from seeping into the combustion chamber below the fuel injector from the joint surface of the fuel injector and the fuel injector hole, however, the cylinder head surface is covered with engine oil. If the sealing between the cylinder head cover around the fuel injector hole and the cylinder head fails, the engine oil on the cylinder head surface will enter the fuel injector hole. Although the engine oil is blocked by the sealing ring in the existing patent document CN205064158U, the engine oil will accumulate in the upper area of the sealing ring in the fuel injector hole, and the cleanliness is low. Moreover, when the fuel injector is disassembled, the sealing of the sealing ring fails, and the accumulated engine oil will enter the combustion chamber below the fuel injector, and starting the vehicle again will cause an illusion of oil burning, resulting in misjudgment of vehicle failures.

[0006] As an improvement, a special-shaped ring is used for sealing around the cylinder head cover. The cylinder head cover and the cylinder head can be directly attached, with small deformation and reliable sealing. However, due to the four-valve arrangement, when sealing around the fuel injector between the cylinder head cover and the cylinder head, the width of the cylinder head cover is not enough to arrange a special-shaped ring or an O-ring groove.

[0007] For some engine models, for example, the width of the joint surface where the cylinder head cover surface fits around the injector hole is small. For some models, the width of the joint surface is only 5 mm, and the diameter of the sealing ring is 3 mm, which requires high machining accuracy for the sealing groove. Moreover, since the unilateral width of the joint surface is only 1 mm, it not only results in poor sealing effect of the joint surface, but also easily damages both sides of the sealing groove and destroys the structure of the cylinder head top surface.

[0008] The disclosure of the above background technical content is only used to assist in understanding the concept and technical solution of the present invention. It does not necessarily belong to the prior art of this patent application. Without clear evidence indicating that the above content was publicly available on the filing date of this patent application, the above background technology should not be used to evaluate the novelty and inventiveness of this application. Summary of the Invention

[0009] One aspect of the object of the present invention is to provide a sealing structure for an injector with good sealing performance, stable structure and convenient disassembly and assembly. Another aspect is to provide an engine with good sealing performance between the injector and the cylinder head cover.

[0010] To this end, the present invention provides a sealing structure for an injector and an engine.

[0011] Preferably, the present invention may further have the following technical features:

[0012] A sealing structure for an injector, comprising an injector, a cylinder head, and a cylinder head cover. An injector hole is provided on the top surface of the cylinder head, the injector is installed in the injector hole, and the cylinder head cover is installed on the top surface of the cylinder head; it further includes a bushing and a second O-ring. A bushing is provided between the injector hole and the injector, and the inner side of the bushing is in clearance fit with the injector; the upper end of the injector hole is reamed to form a counterbore at the upper end of the injector hole; the upper end of the bushing protrudes above the top surface of the cylinder head, and the cylinder head cover is provided with a corresponding relief groove to avoid the bushing body protruding above the top surface of the cylinder head; the counterbore and the bushing cooperate to form a second sealing groove, and the second O-ring is installed in the second sealing groove.

[0013] Further, after the second O-ring is squeezed and deformed, the second O-ring abuts against the bushing.

[0014] Further, the distance from the side wall of the counterbore to the inner wall of the injector hole is 0.5 - 1.5 mm greater than the diameter of the second O-ring.

[0015] Further, the distance from the side wall of the counterbore to the inner wall of the injector hole is 0.5 - 1 mm greater than the diameter of the second O-ring.

[0016] Further, the height of the counterbore is less than the diameter of the second O-ring.

[0017] Further, the outer side of the bushing is in clearance fit with the fuel injector hole, and the clearance is smaller than the clearance between the bushing and the fuel injector.

[0018] Further, a first sealing groove is formed in the upper part of the fuel injector hole, and a first O-ring is arranged in the first sealing groove.

[0019] Further, the bushing is a copper bushing or a steel bushing.

[0020] An engine includes the sealing structure of the above-mentioned fuel injector.

[0021] Further, a third sealing groove is formed around the bottom surface of the cylinder head cover, and a third sealing ring is arranged in the third sealing groove, and the third sealing ring is used to realize the sealing between the inside and the outside of the cylinder head cover.

[0022] The beneficial effects of the present invention compared with the prior art include: by adding a bushing, the casting difficulty of the cylinder head is reduced, the rejection rate is reduced, and a guiding and transitional function is achieved. At the same time, the bushing protrudes above the top surface of the cylinder head. On the one hand, the processing difficulty of the bushing can be greatly reduced. On the other hand, a second sealing groove is formed in cooperation with the counterbore to avoid damage to the second O-ring. On the other hand, it can prevent engine oil from flowing between the bushing and the fuel injector, ensuring the disassembly, assembly and cleaning degree of the fuel injector. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a top view of the present invention.

[0024] Figure 2 is Figure 1 a sectional view taken along the line B-B in

[0025] Figure 3 is Figure 2 an enlarged view at C in

[0026] Figure 4 is a bottom view of the cylinder head cover of the present invention.

[0027] Figure 5 is a structural diagram of the top surface of the cylinder head of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0028] The present invention will be further described in detail below in conjunction with the specific embodiments and with reference to the accompanying drawings. It should be emphasized that the following description is merely exemplary and is not intended to limit the scope of the present invention and its applications.

[0029] Referring to the following drawings, non-limiting and non-exclusive embodiments will be described, in which the same reference numerals represent the same components, unless otherwise specifically stated.

[0030] As Figures 1 to 5A sealing structure of an injector is shown, which includes an injector 1, a cylinder head 3, and a cylinder head cover 2. A fuel injector hole is provided on the top surface of the cylinder head 3, the injector 1 is installed in the fuel injector hole, and the cylinder head cover 2 is installed on the top surface of the cylinder head. It also includes a bushing 4 and a second O-ring 5. A bushing 4 is provided between the fuel injector hole and the injector 1. The casting accuracy requirement of the fuel injector hole is high. By adding the bushing 4, the casting difficulty of the cylinder head 3 is reduced, and the rejection rate is decreased. The inner side of the bushing 4 is in clearance fit with the injector 1, and the outer side is in small clearance fit with the fuel injector hole to ensure tightness and installation accuracy. The upper end of the fuel injector hole is reamed to form a counterbore 6 at the upper end of the fuel injector hole, and the overall fuel injector hole has a countersunk hole structure. The upper end horizontal height of the bushing 4 is higher than the horizontal height of the top surface of the cylinder head 3. The cylinder head cover 2 is provided with a corresponding relief groove 8 to avoid the bushing body protruding above the top surface of the cylinder head 3 and prevent the bushing 4 from interfering with the installation and fixation of the cylinder head cover 2. The counterbore 6 and the bushing 4 cooperate to form a second sealing groove, and the second O-ring 5 is installed in the second sealing groove. In this embodiment, the bushing 4 protrudes above the top surface of the cylinder head 3. On the one hand, the processing difficulty of the bushing 4 can be greatly reduced; on the other hand, it cooperates with the counterbore 6 to form a second sealing groove to avoid damage to the second O-ring 5. If the bushing 4 is flush with the top surface of the cylinder head 3, due to processing errors, the processing difficulty is high. If the height of the bushing 4 is lower than the top surface of the cylinder head 3, it will cause a notch in the second sealing groove. When the second O-ring is squeezed, the second O-ring deforms towards the notch and is likely to be cut by the edges of the notch (the upper edge of the bushing and the bottom edge of the counterbore), resulting in damage to the second O-ring and affecting the sealing effect.

[0031] In the above embodiment, during assembly, the injector 1 and the bushing 4 are assembled into the fuel injector hole on the cylinder head 3, then the second O-ring 5 is installed in the second sealing groove, and then the cylinder head cover 2 is assembled onto the cylinder head 3. The cylinder head cover 2 is used to compress the second O-ring 5, so that the cylinder head 3 and the cylinder head cover 2 cooperate with the second O-ring 5 to form a sealing surface around the injector 1, preventing the engine oil on the top surface of the cylinder head 3 from seeping into the fuel injector hole and improving the disassembly, installation and cleaning degree of the injector 1. At the same time, preferably, after the second O-ring 5 is squeezed and deformed, the second O-ring 5 abuts against the outer side of the bushing 4 to form another sealing surface.

[0032] Specifically, the distance from the side wall of the counterbore 6 to the inner wall of the fuel injector hole is 0.5 - 1.5 mm greater than the diameter of the second O-ring 5, preferably 0.5 - 1 mm. The height of the counterbore 6 is less than the diameter of the second O-ring 5.

[0033] A first sealing groove is provided in the upper part of the fuel injector hole, and a first O-ring 9 is provided in the first sealing groove to seal the joint surface between the bushing 4 and the fuel injector hole.

[0034] The bushing 4 is a copper bushing or a steel bushing.

[0035] An engine includes the sealing structure of the injector described above. Specifically, third sealing grooves are formed around the bottom surface of the cylinder head cover 2, and third sealing rings 10 are arranged in the third sealing grooves. The third sealing rings 10 are used to seal the inside and outside of the cylinder head cover 2 to prevent the engine oil on the top surface of the cylinder head 3 from leaking out of the cylinder head cover 2.

[0036] Those skilled in the art will recognize that numerous variations to the above description are possible, so the embodiments and the drawings are only used to describe one or more specific embodiments.

[0037] Although the exemplary embodiments considered to be the present invention have been described and recited, those skilled in the art will understand that various changes and substitutions can be made thereto without departing from the spirit of the present invention. Additionally, many modifications can be made to adapt a particular situation to the teachings of the present invention without departing from the central concept described herein. Therefore, the present invention is not limited to the specific embodiments disclosed herein, but the present invention may also include all embodiments and their equivalents falling within the scope of the present invention.

Claims

1. A sealing structure of an injector, comprising an injector, a cylinder head, and a cylinder head cover. An injector hole is provided on the top surface of the cylinder head, the injector is installed in the injector hole, and the cylinder head cover is installed on the top surface of the cylinder head; characterized in that: It further includes a bushing and a second O-ring. A bushing is provided between the fuel injector hole and the fuel injector, and the inner side of the bushing is in clearance fit with the fuel injector. The upper end of the fuel injector hole is reamed to form a counterbore at the upper end of the fuel injector hole. The upper end of the bushing protrudes above the top surface of the cylinder head, and the cylinder head cover is provided with a corresponding relief groove to avoid the bushing body protruding above the top surface of the cylinder head. The counterbore and the bushing cooperate to form a second sealing groove, and the second O-ring is installed in the second sealing groove.

2. The sealing structure of an injector according to claim 1, characterized in that: After the second O-ring is extruded and deformed, the second O-ring abuts against the bushing.

3. The sealing structure of an injector according to claim 2, characterized in that: The distance from the side wall of the counterbore to the inner wall of the fuel injector hole is 0.5 - 1.5 mm greater than the diameter of the second O-ring.

4. The sealing structure of an injector according to claim 2, characterized in that: The distance from the side wall of the counterbore to the inner wall of the fuel injector hole is 0.5 - 1 mm greater than the diameter of the second O-ring.

5. The sealing structure of an injector according to claim 1, characterized in that: The height of the counterbore is less than the diameter of the second O-ring.

6. The sealing structure of an injector according to claim 1, characterized in that: The outer side of the bushing is in clearance fit with the fuel injector hole, and this clearance is less than the clearance between the bushing and the fuel injector.

7. The sealing structure of an injector according to claim 6, characterized in that: A first sealing groove is provided at the upper part of the fuel injector hole, and a first O-ring is provided in the first sealing groove.

8. The sealing structure of an injector according to claim 1, characterized in that: The bushing is a copper bushing or a steel bushing.

9. An engine, characterized in that: It includes the sealing structure of the fuel injector according to claim 1.

10. The engine according to claim 9, characterized in that: A third sealing groove is provided around the bottom surface of the cylinder head cover, and a third sealing ring is provided in the third sealing groove to achieve the sealing between the inside and the outside of the cylinder head cover by using the third sealing ring.

Images