Engine exhaust gas recirculation system and engine assembly

Abstract

The utility model relates to the technical field of engines, and discloses an engine exhaust gas recirculation system and an engine assembly.The engine exhaust gas recirculation system comprises an exhaust gas backflow pipeline used for leading exhaust gas into a gas inlet pipeline from an exhaust pipeline of an engine, the exhaust gas backflow pipeline comprises a body part and a diameter expanding part, and the body part is communicated with the diameter expanding part; the inner diameter of the expanding part is larger than that of the body part, and the expanding part is provided with a cooling structure. According to the engine exhaust gas recirculation system, the diameter expanding part with the inner diameter larger than that of the body part is arranged on the exhaust gas backflow pipeline, the cooling structure is arranged on the diameter expanding part, the diameter expanding part can increase the contact area between exhaust gas and the pipe wall of the exhaust gas backflow pipeline, the heat dissipation effect of the exhaust gas is improved, and meanwhile the cooling structure is arranged on the diameter expanding part, so that the cooling effect is improved. The heat dissipation effect of exhaust gas can be further improved, the temperature of the exhaust gas is reduced, and the exhaust gas recirculation rate is increased.

Description

Technical Field

[0001] The utility model relates to the technical field of engines, in particular to an engine exhaust gas recirculation system and an engine assembly. Background Art

[0002] This section merely provides background information related to the present disclosure and is not necessarily prior art.

[0003] In the context of emission regulations being upgraded, the engine adopts the EGR route (i.e., exhaust gas recirculation system) to reduce the generation of NOx and improve the original emission level of the engine. Under normal operating conditions, the temperature of EGR exhaust gas is between 70℃ and 180℃. In order to increase the EGR rate, water cooling is currently used to cool the EGR exhaust gas. However, the structure of this water cooling system is relatively complex, which will result in a higher overall system cost. Utility Model Content

[0004] The purpose of the utility model is to at least solve the problem that the system structure is relatively complex and leads to high cost when cooling EGR exhaust gas by water cooling. This purpose is achieved through the following technical solutions:

[0005] The first aspect of the utility model provides an engine exhaust gas recirculation system, comprising:

[0006] The exhaust gas reflow pipeline is used to introduce exhaust gas from the exhaust pipeline of the engine into the intake pipeline. The exhaust gas reflow pipeline includes a main body and an expanded diameter portion. The main body is connected to the expanded diameter portion, and the inner diameter of the expanded diameter portion is larger than the inner diameter of the main body. The expanded diameter portion has a cooling structure.

[0007] The engine exhaust gas recirculation system of the utility model is provided with an expanded diameter portion whose inner diameter is larger than the inner diameter of the main body portion on the exhaust gas reflow pipeline, and a cooling structure is provided on the expanded diameter portion. The expanded diameter portion can increase the contact area between the exhaust gas and the pipe wall of the exhaust gas reflow pipeline, thereby improving the heat dissipation effect of the exhaust gas. At the same time, the cooling structure is provided on the expanded diameter portion, which can further improve the heat dissipation effect of the exhaust gas, reduce the temperature of the exhaust gas, and improve the exhaust gas recirculation rate.

[0008] In addition, the engine exhaust gas recirculation system according to the utility model may also have the following additional technical features:

[0009] In some embodiments of the present invention, the cooling structure includes a plurality of folds protruding from a surface of the expanded diameter portion and extending continuously.

[0010] In some embodiments of the present invention, each of the folds is arranged around the axis of the expanded diameter portion and along the circumference of the expanded diameter portion.

[0011] In some embodiments of the present invention, the longitudinal sections of the plurality of folds are wavy.

[0012] In some embodiments of the present invention, the interior of the expanded diameter portion is a hollow structure, and the cross-section of the expanded diameter portion is cylindrical.

[0013] In some embodiments of the present invention, there are multiple diameter-enlarging parts, and the multiple diameter-enlarging parts are arranged at intervals along the length direction of the exhaust gas reflow pipe.

[0014] In some embodiments of the present invention, a transition point between the enlarged diameter portion and the main body portion is a curved surface.

[0015] In some embodiments of the present invention, the main body portion includes an upstream pipe section and a downstream pipe section, and the upstream pipe section and the downstream pipe section are arranged along the exhaust gas flow direction and are respectively connected to two ends of the expanded diameter portion.

[0016] In some embodiments of the present invention, the diameter of the expanded diameter portion is 2.5 to 3 times the diameter of the main body portion.

[0017] Another aspect of the utility model provides an engine assembly, comprising an engine exhaust gas recirculation system as described in any one of the above items, and also comprising an engine body, an exhaust pipe and an intake pipe connected to the engine body, and the two ends of the exhaust gas return pipe are respectively connected to the exhaust pipe and the intake pipe. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] By reading the detailed description of the preferred embodiment below, various other advantages and benefits will become clear to those of ordinary skill in the art. The accompanying drawings are only used for the purpose of illustrating the preferred embodiment and are not to be considered as limiting the present invention. Moreover, the same reference numerals are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0019] Figure 1 The structure diagram of the engine exhaust gas recirculation system according to the embodiment of the utility model is schematically shown;

[0020] Figure 2 A partial enlarged view of an engine exhaust gas recirculation system according to an embodiment of the utility model is schematically shown;

[0021] Figure 3 A partial cross-sectional view of an engine exhaust gas recirculation system according to an embodiment of the present utility model is schematically shown.

[0022] The reference numerals are as follows:

[0023] 1. exhaust gas return pipeline; 10. expansion part; 100. expansion part body; 101. fold; 11. upstream pipe section; 12. downstream pipe section;

[0024] 2. Exhaust pipe;

[0025] 3. Air intake pipe;

[0026] 4. EGR valve. DETAILED DESCRIPTION

[0027] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0028] It should be understood that the terms used herein are only for the purpose of describing specific example embodiments and are not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms "one", "an" and "said" as used herein may also be meant to include plural forms. The terms "include", "comprise", "contain", and "have" are inclusive, and therefore specify the existence of stated features, steps, operations, elements and / or parts, but do not exclude the existence or addition of one or more other features, steps, operations, elements, parts, and / or combinations thereof. The method steps, processes, and operations described herein are not interpreted as necessarily requiring them to be performed in the specific order described or illustrated, unless the execution order is clearly indicated. It should also be understood that additional or alternative steps may be used.

[0029] Although the terms first, second, third, etc. can be used in the text to describe multiple elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms can only be used to distinguish an element, component, region, layer or section from another region, layer or section. Unless the context clearly indicates, terms such as "first", "second" and other numerical terms do not imply order or sequence when used in the text. Therefore, the first element, component, region, layer or section discussed below can be referred to as the second element, component, region, layer or section without departing from the teaching of the example embodiments.

[0030] For ease of description, spatial relative terms may be used herein to describe the relationship of one element or feature relative to another element or feature as shown in the figure, such as "inside", "outside", "inner side", "outer side", "below", "below", "above", "above", etc. Such spatial relative terms are intended to include different orientations of the device in use or operation in addition to the orientation depicted in the figure. For example, if the device in the figure is turned over, then the elements described as "below other elements or features" or "below other elements or features" will subsequently be oriented as "above other elements or features" or "above other elements or features". Therefore, the example term "below..." can include both above and below orientations.

[0031] In the context of emission regulations being upgraded, the engine adopts the EGR route (i.e., exhaust gas recirculation system) to reduce the generation of NOx and improve the original emission level of the engine. Under normal operating conditions, the temperature of EGR exhaust gas is between 70℃ and 180℃. In order to increase the EGR rate, water cooling is currently used to cool the EGR exhaust gas.

[0032] However, the traditional water-cooled EGR system is mainly composed of EGR valve, EGR cooler, one-way valve, venturi tube, EGR exhaust gas return pipeline and other structures. During cooling, EGR exhaust gas enters the EGR cooler through the EGR valve. The EGR cooler is equipped with a grille structure with circulating cooling water inside. When the high-temperature EGR exhaust gas flows through the EGR cooler, it contacts the outer surface of the grille and achieves a cooling effect through heat exchange. This system structure is relatively complex and will result in a higher overall system cost. If the non-cooled EGR method is adopted, the non-cooled EGR system is mainly composed of an EGR valve and an EGR exhaust gas pipeline, and the structure is relatively simple, but the system can only be used in areas with a driving pressure difference. With the application of high-efficiency superchargers, the area with a driving pressure difference in all working conditions is getting smaller and smaller, resulting in a relatively limited area of ​​application.

[0033] In view of this, the present embodiment provides an exhaust gas recirculation system, which aims to solve the above-mentioned technical problems by adding at least one expanded diameter portion 10 to the exhaust gas return pipe 1, and providing a cooling structure on the expanded diameter portion 10, so as to increase the contact area between the exhaust gas and the pipe wall of the exhaust gas return pipe 1, thereby improving the heat dissipation effect of the exhaust gas and the exhaust gas recirculation rate.

[0034] like Figures 1 to 3As shown, according to the embodiment of the utility model, an engine exhaust gas recirculation system is proposed, the engine exhaust gas recirculation system comprises an exhaust gas return pipe 1, the exhaust gas return pipe 1 is used to introduce exhaust gas from the exhaust pipe 2 of the engine into the intake pipe 3, the exhaust gas return pipe 1 comprises a main body and an expanded diameter portion 10, the main body is connected with the expanded diameter portion 10, and the inner diameter of the expanded diameter portion 10 is larger than the inner diameter of the main body, and the expanded diameter portion 10 has a cooling structure. When the exhaust gas recirculation is performed, the engine exhaust gas from the exhaust pipe 2 enters the exhaust gas return pipe 1, and the exhaust gas passes through the expanded diameter portion 10 during the process of flowing in the exhaust gas return pipe 1. When the exhaust gas reaches the expanded diameter portion 10, since the inner diameter of the expanded diameter portion 10 is larger than the inner diameter of the main body, the contact area between the exhaust gas and the pipe wall of the exhaust gas return pipe 1 is increased, and the cooling structure on the expanded diameter portion 10 further increases the contact area between the exhaust gas and the pipe wall, and at the same time increases the heat exchange time between the exhaust gas and the outside, improves the heat dissipation effect of the exhaust gas, and increases the heat dissipation speed. Then the exhaust gas passes through the exhaust gas return pipe 1 and enters the intake pipe 3, and is then led back to the engine cylinder through the intake pipe 3 to mix with the fresh intake air of the engine to perform exhaust gas recirculation, so as to improve the engine working efficiency, improve the combustion environment, reduce the engine load, reduce the emission of NOx compounds, reduce knocking, and extend the service life of the engine.

[0035] The engine exhaust gas recirculation system of the utility model is provided with an expansion part 10 whose inner diameter is larger than the inner diameter of the main body on the exhaust gas reflow pipeline 1, and a cooling structure is provided on the expansion part 10. The expansion part 10 can increase the contact area between the exhaust gas and the pipe wall of the exhaust gas reflow pipeline 1, thereby improving the heat dissipation effect of the exhaust gas. At the same time, the cooling structure is provided on the expansion part 10, which can further improve the heat dissipation effect of the exhaust gas, reduce the temperature of the exhaust gas, and improve the exhaust gas recirculation rate. Therefore, the temperature of the exhaust gas can be reduced by the above structure, so that it works in a suitable temperature range to improve the EGR rate. Compared with the traditional method of using a water-cooled EGR system to cool the exhaust gas, the present application can effectively simplify the system structure and reduce the cost at the same time; compared with the method of using non-cooled EGR, the application range of EGR is increased while the EGR rate is increased. In summary, the engine exhaust gas recirculation system provided by this embodiment is conducive to increasing the application range of EGR at a low cost and improving the EGR rate at the same time.

[0036] In other embodiments, the solution of the present application can also be applied to the exhaust gas return pipe 1 with an EGR cooler, and the present application does not limit this. On the basis of the exhaust gas return pipe 1 being provided with an EGR cooler, the expansion portion 10 and the cooling structure of the present application can achieve an efficient auxiliary cooling effect of the external natural wind, further improving the cooling effect while helping to reduce the operating cost of the system.

[0037] In some embodiments of the present invention, the cooling structure includes a plurality of folds 101 protruding from the surface of the expanding portion 10 and extending continuously. Specifically, in the present embodiment, each fold 101 is arranged around the axis of the expanding portion 10 and along the circumference of the expanding portion 10, and the expanding portion 10 includes an expanding portion body 100, that is, a plurality of folds 101 are arranged on the expanding portion body 100, and the plurality of folds 101 are arranged in sequence along the length direction of the expanding portion body 100, and each fold 101 is arranged around the axis direction of the expanding portion body 100 and along the periphery of the expanding portion body 100, and the protrusion height and width of each fold 101 are the same. The plurality of folds 101 and the expanding portion body 100 are an integral structure to ensure the overall strength of the expanding portion 10.

[0038] In this embodiment, the entire material of the expanded diameter portion 10 is stainless steel, which has the characteristics of being non-corrosive, non-deformable, high in strength, good in safety, long in service life, and good in sealing.

[0039] In other embodiments, the plurality of pleats 101 may be arranged in sequence around the axis of the diameter-enlarging portion body 100, and each pleat 101 is arranged along the length direction of the diameter-enlarging portion body 100. In addition, the number of pleats 101 may be adjusted according to the length, diameter, etc. of the diameter-enlarging portion body 100, and / or the parameters such as the protrusion height and width of each pleat 101 may be adjusted according to actual conditions, which is not limited in the present application.

[0040] In some embodiments of the present invention, the longitudinal sections of the plurality of folds 101 are wavy. Figure 3 The longitudinal section of the pleat 101 refers to the section along the axial direction of the expanded diameter portion 10. The longitudinal section of each pleat 101 is arc-shaped and connected end to end, and the connection of each pleat 101 is smoothly transitioned, so that the multiple pleats 101 form a wave shape.

[0041] In other embodiments, the longitudinal cross-section of each fold 101 may also be triangular, rectangular or irregular in shape, as long as the fold 101 protrudes from the surface of the expanded diameter portion 10 to increase the heat dissipation area of ​​the expanded diameter portion 10. This application is not limited to this.

[0042] In some embodiments of the utility model, the inside of the expanded diameter portion 10 is a hollow structure, and the cross section of the expanded diameter portion 10 is cylindrical. Specifically, the expanded diameter portion 10 includes a first end and a second end, and the cross section of the expanded diameter portion 10 is cylindrical, that is, the diameters of the first end and the second end are equal. Since the pipe wall of the expanded diameter portion 10 is thinner, the diameter of the expanded diameter portion 10 can be regarded as equal to the inner diameter of the expanded diameter portion 10. The inner diameter of the expanded diameter portion 10 is larger than the inner diameter of the main body. When the exhaust gas recirculation is performed, the exhaust gas passes through the expanded diameter portion 10 in the process of flowing in the exhaust gas return pipe 1. When the exhaust gas reaches the expanded diameter portion 10, the expanded diameter portion 10 with a hollow interior and an increased diameter increases the contact area between the exhaust gas and the pipe wall of the exhaust gas return pipe 1, thereby improving the heat dissipation effect of the exhaust gas.

[0043] In this embodiment, the main body includes an upstream pipe section 11 and a downstream pipe section 12, which are arranged along the exhaust gas flow direction and are respectively connected to the two ends of the expanded diameter section 10. That is, the first end of the expanded diameter section 10 is connected to the upstream pipe section 11, and the second end is connected to the downstream pipe section 12.

[0044] In other embodiments, the expanded diameter portion 10 may also be other shapes such as a sphere, or the diameter of the first end may be larger than the diameter of the second end, and the diameter of the second end may be larger than the diameter of the exhaust gas return pipe 1, or the diameter of the first end may be larger than the diameter of the exhaust gas return pipe 1, and the diameter of the exhaust gas return pipe 1 is the same as the diameter of the second end, or other forms, etc., and the present application does not limit this.

[0045] In some embodiments of the utility model, the transition between the expanded diameter portion 10 and the main body is a curved surface. By setting the transition between the expanded diameter portion 10 and the main body as a curved surface, the exhaust gas entering the expanded diameter portion 10 flows smoothly, which can play a better guiding role when the exhaust gas passes through the expanded diameter portion 10, so that the exhaust gas flows to the expanded diameter portion 10 along the smooth transition connection, and can fully contact the expanded diameter portion 10, that is, the folds 101 for heat exchange, further improving the heat dissipation efficiency and heat dissipation effect.

[0046] In some embodiments of the present invention, there are multiple diameter-enlarging parts 10, and the multiple diameter-enlarging parts 10 are arranged at intervals along the length direction of the exhaust gas reflow pipe.

[0047] See also Figure 1 In this embodiment, there are three expanded diameter portions 10, which are spaced apart along the length direction of the main body. The exhaust gas passes through the three expanded diameter portions 10 in sequence during the flow in the exhaust gas reflow pipe 1, which can further improve the heat dissipation efficiency and effect of the exhaust gas.

[0048] In other embodiments, the number of the expanded diameter portions 10 may be set to one, two, four, etc. according to actual conditions, and the present application does not limit this.

[0049] In some embodiments of the utility model, the diameter of the enlarged diameter portion 10 is 2.5 to 3 times the diameter of the main body portion. In this embodiment, the diameters of the upstream pipe section 11 and the downstream pipe section 12 are equal. When the enlarged diameter portion 10 is cylindrical, the diameter D2 of the enlarged diameter portion 10 is generally set to 2.5 to 3 times the diameter D1 of the upstream pipe section 11, for example, the diameter D2 of the enlarged diameter portion 10 is 2.5 times the diameter D1 of the upstream pipe section 11, or the diameter D2 of the enlarged diameter portion 10 is 3 times the diameter D1 of the upstream pipe section 11, or the diameter D2 of the enlarged diameter portion 10 is any multiple value from 2.5 to 3 times the diameter D1 of the upstream pipe section 11.

[0050] The second aspect of the utility model proposes an engine assembly, including an engine body, an exhaust pipe 2, an intake pipe 3 and the above-mentioned engine exhaust gas recirculation system, the exhaust pipe 2 and the intake pipe 3 are respectively connected to the engine body, and the two ends of the exhaust gas return pipe 1 are respectively connected to the exhaust pipe 2 and the intake pipe 3. Specifically, the upstream pipe section 11 is connected to the exhaust pipe 2, and the downstream pipe section 12 is connected to the intake pipe 3. In this embodiment, the engine assembly also includes an EGR valve 4, which is arranged at the connection between the exhaust pipe 2 and the exhaust gas return pipe 1, and is used to control the flow of exhaust gas entering the exhaust gas return pipe 1 after flowing out of the exhaust pipe 2.

[0051] Of course, the engine assembly of this embodiment also has other structures and components that existing engine assemblies have, such as an electronic control unit, etc. Since this embodiment does not involve these structures and components, they will not be described in detail.

[0052] In order to further understand the engine exhaust gas recirculation system of this embodiment, the working process of the engine assembly of this embodiment is described below in conjunction with the accompanying drawings:

[0053] During normal operation of the engine, the engine exhaust gas from the exhaust pipe 2 passes through the EGR valve 4 and then enters the exhaust gas recirculation pipe 1. The exhaust gas passes through the expansion portion 10 during the flow in the exhaust gas recirculation pipe 1. When the exhaust gas reaches the expansion portion 10, since the diameter of the expansion portion 10 is larger than the diameter of the exhaust gas recirculation pipe 1, the contact area between the exhaust gas and the pipe wall of the exhaust gas recirculation pipe 1 is increased. At the same time, the expansion portion 10 has a plurality of folds 101, which further increases the contact area between the exhaust gas and the pipe wall, thereby improving the heat dissipation effect of the exhaust gas and increasing the heat dissipation speed. Then, the exhaust gas passes through the exhaust gas recirculation pipe 1 and then enters the intake pipe 3, and after being mixed with the fresh intake air in the intake pipe, enters the cylinder to participate in combustion.

[0054] The engine assembly of this embodiment is provided with at least one expanded diameter portion 10 on the exhaust gas return pipe 1, and a cooling structure is provided on the expanded diameter portion 10. The expanded diameter portion 10 can increase the contact area between the exhaust gas and the pipe wall of the exhaust gas return pipe 1, thereby improving the heat dissipation effect of the exhaust gas. At the same time, a plurality of pleat structures 101 are provided on the expanded diameter portion 10, so that when the exhaust gas flows through the expanded diameter portion 10, the exhaust gas can fully contact with the outside air, thereby increasing the windward area of ​​the pipe, further improving the heat dissipation effect of the exhaust gas, reducing the temperature of the exhaust gas, and increasing the application range of EGR while improving the EGR rate.

[0055] The above is only a preferred specific implementation of the utility model, but the protection scope of the utility model is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the utility model should be included in the protection scope of the utility model. Therefore, the protection scope of the utility model should be based on the protection scope of the claims.

Claims

1. An engine exhaust gas recirculation system, characterized in that: include: An exhaust gas recirculation pipeline is used to introduce exhaust gas from the exhaust pipeline of the engine into the intake pipeline. The exhaust gas recirculation pipeline includes a main body and an expanded diameter portion. The main body is connected to the expanded diameter portion, and the inner diameter of the expanded diameter portion is larger than the inner diameter of the main body. The expanded diameter portion is provided with a cooling structure, and the cooling structure includes a plurality of folds protruding from the surface of the expanded diameter portion and extending continuously, each of the folds is arranged around the axis of the expanded diameter portion and along the circumference of the expanded diameter portion; the number of the expanded diameter portions is multiple, and the multiple expanded diameter portions are arranged at intervals along the length direction of the exhaust gas recirculation pipeline.

2. The engine exhaust gas recirculation system according to claim 1, characterized in that: The longitudinal sections of the plurality of folds are wavy.

3. The engine exhaust gas recirculation system according to claim 1, characterized in that: The inside of the expanded diameter portion is a hollow structure, and the cross section of the expanded diameter portion is cylindrical.

4. The engine exhaust gas recirculation system according to claim 3, characterized in that: The transition between the enlarged diameter portion and the main body portion is a curved surface.

5. The engine exhaust gas recirculation system according to claim 3, characterized in that: The main body portion includes an upstream pipe section and a downstream pipe section, wherein the upstream pipe section and the downstream pipe section are arranged along the exhaust gas flow direction and are respectively connected to two ends of the expanded diameter portion.

6. The engine exhaust gas recirculation system according to claim 3, characterized in that: The diameter of the expanded diameter portion is 2.5 to 3 times the diameter of the main body portion.

7. An engine assembly, characterized in that: An engine exhaust gas recirculation system comprising the engine exhaust gas recirculation system as claimed in any one of claims 1 to 6, further comprising an engine body, an exhaust pipe and an intake pipe connected to the engine body, wherein both ends of the exhaust gas return pipe are respectively connected to the exhaust pipe and the intake pipe.

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