Air inlet rotational flow-combined injection combustion system of opposed-piston two-stroke diesel engine

Abstract

The invention provides an opposed-piston two-stroke diesel engine air inlet rotational flow-combined injection combustion system which comprises an air cylinder sleeve, an air inlet piston, an exhaust piston and oil injectors, the air inlet piston and the exhaust piston are correspondingly arranged in the air cylinder sleeve and form a combustion space, and the multiple oil injectors are evenly distributed in the position, corresponding to the combustion space, of the air cylinder sleeve in the circumferential direction. Air inlets and air outlets are formed in the two ends of the air cylinder sleeve in the circumferential direction respectively, the multiple air inlets are matched to form a spiral shape, the air outlets are composed of straight air ports and inclined air ports, external air enters the air cylinder through the air inlets to form air inlet rotational flow, and a formed rotational flow layer pushes waste gas to be exhausted from the air outlets along the axis of the air cylinder sleeve. Fuel oil injected by the multiple oil injectors forms a space oil beam, and the injection direction of the space oil beam is opposite to the rotation direction of air inlet rotational flow formed in the cylinder, so that oil and gas are fully mixed and combusted. According to the invention, oil and gas can be rapidly and fully mixed, the combustion process is improved, and the combustion efficiency is improved.

Description

Technical Field

[0001] The present application belongs to the field of engine combustion technology, and in particular relates to an intake swirl-combined injection combustion system for an opposed-piston two-stroke diesel engine. Background Art

[0002] Compared to traditional four-stroke diesel engines, opposed-piston two-stroke diesel engines offer advantages such as higher power density and lower specific heat dissipation. Opposed-piston two-stroke diesel engines lack a cylinder head or valvetrain. The combustion chamber consists of the top surfaces of the intake and exhaust pistons, and the fuel injectors are located on the cylinder sidewalls.

[0003] However, due to its short scavenging time and simultaneous intake and exhaust processes, there are problems such as a large residual exhaust gas coefficient in the cylinder and poor scavenging quality. In addition, the multi-injector arrangement easily causes collision of fuel sprays or oil beams hitting the inner wall of the cylinder liner, which limits the development of the oil beam and affects the oil-gas mixing process, leading to incomplete combustion and low combustion efficiency. Summary of the Invention

[0004] In view of this, the present application aims to propose an opposed-piston two-stroke diesel engine intake swirl-combined injection combustion system to solve the problems of incomplete combustion and low scavenging efficiency in opposed-piston two-stroke diesel engines.

[0005] To achieve the above objectives, the technical solution of this application is implemented as follows: The present application provides an intake swirl-combined injection combustion system for an opposed-piston two-stroke diesel engine, comprising a cylinder liner, an intake piston, an exhaust piston, and a fuel injector. The intake piston and the exhaust piston are correspondingly disposed within the cylinder liner to form a combustion space. A plurality of fuel injectors are evenly arranged circumferentially on the cylinder liner corresponding to the combustion space. An intake port and an exhaust port are circumferentially arranged on both ends of the cylinder liner, wherein a plurality of the intake ports cooperate to form a spiral shape, and the exhaust port is composed of a straight port and an inclined port. External air enters the cylinder through the intake port to form an intake swirl flow. The formed swirl layer pushes exhaust gas along the axis of the cylinder liner to be discharged from the exhaust port. The fuel injected by the multiple injectors forms a spatial oil beam, and the injection direction of the spatial oil beam is opposite to the rotation direction of the intake vortex formed in the cylinder, so that the oil and gas are fully mixed and burned.

[0006] Furthermore, each of the air inlets has a cashew-shaped structure, and several of the air inlets are evenly arranged at one end of the cylinder liner close to the intake piston, and the distance between each of the air inlets and the center plane of the cylinder liner is equal.

[0007] Furthermore, the plurality of exhaust ports are symmetrically arranged with the plane passing through the central axis of the cylinder liner as the center, and the distance between each exhaust port and the central plane of the cylinder liner is equal, wherein the inclined air ports are arranged on both sides of the middle straight air port.

[0008] Furthermore, the number of the fuel injectors is four, two of the fuel injectors are evenly circumferentially arranged at the center plane of the cylinder liner, and the spray hole of each fuel injector is an oblique hole arrangement.

[0009] Furthermore, the diameters of the intake piston and the exhaust piston are both in the range of 80 mm to 140 mm.

[0010] Compared with the prior art, the opposed-piston two-stroke diesel engine intake swirl-combined injection combustion system described in this application has the following beneficial effects: (1) Under the action of the spiral air port, the present invention can effectively organize the intake swirl flow, and the swirl layer formed can push the exhaust gas out of the cylinder along the axis of the cylinder liner, thereby improving the scavenging efficiency; the exhaust ports arranged symmetrically on both sides can reduce the exhaust flow loss, and increasing the flow capacity of the exhaust ports can effectively organize the intake swirl flow, and the swirl layer formed can push the exhaust gas out of the cylinder along the axis of the cylinder liner, thereby improving the scavenging efficiency; (2) The spatial oil beam distribution set up in this application avoids the interference of oil beams injected by multiple injectors, and cooperates with the intake vortex formed in the cylinder to achieve rapid and sufficient mixing of oil and gas, improve the combustion process, and enhance combustion efficiency. At the same time, the complex spatial oil beam combined with the intake vortex in the cylinder can keep the high-temperature area formed by flame combustion away from the cylinder wall, thereby reducing the heat load of the cylinder liner and reducing the heat loss at the cylinder liner position. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of this application. The exemplary embodiments and descriptions of this application are intended to explain this application and do not constitute an improper limitation on this application. In the accompanying drawings: Figure 1 This is a schematic structural diagram of an opposed-piston two-stroke diesel engine intake swirl-combined injection combustion system according to an embodiment of the present application; Figure 2 This is a schematic diagram of the exhaust port arrangement according to an embodiment of the present application; Figure 3 This is a schematic diagram of the spatial oil beam distribution described in an embodiment of the present application.

[0012] Description of reference numerals: 1-Cylinder liner; 2-Intake port; 3-Intake piston; 4-Exhaust piston; 5-Exhaust port; 6-Injector. DETAILED DESCRIPTION

[0013] In order to make the objectives, technical solutions and advantages of this application more clear, this application is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0014] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present application should have the usual meanings understood by people with ordinary skills in the field to which this application belongs. The "first", "second" and similar words used in the embodiments of the present application do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0015] See also Figure 1 As shown, this embodiment provides an opposed-piston two-stroke diesel engine intake swirl-combined injection combustion system, including a cylinder liner, an intake piston, an exhaust piston, and a fuel injector. The intake piston and the exhaust piston are correspondingly arranged in the cylinder liner. The diameter of the intake piston and the exhaust piston are both in the range of 80mm-140mm, and a combustion space is formed. A plurality of fuel injectors are evenly arranged circumferentially on the cylinder liner corresponding to the combustion space. An intake port and an exhaust port are circumferentially arranged on both ends of the cylinder liner, wherein the plurality of intake ports cooperate to form a spiral shape, and the exhaust port is composed of a straight port and an inclined port. External air enters the cylinder through the intake port to form an intake swirl flow. The formed swirl layer pushes the exhaust gas out of the exhaust port along the axis of the cylinder liner. The fuel injected by multiple injectors forms a spatial oil beam, and the injection direction of the spatial oil beam is opposite to the rotation direction of the intake vortex formed in the cylinder, so that the oil and gas are fully mixed and burned.

[0016] The combustion system described in this embodiment solves the problems of incomplete combustion and low scavenging efficiency in opposed-piston two-stroke diesel engines, and can achieve rapid and sufficient mixing of oil and gas, improve the combustion process, and enhance the combustion efficiency of the engine.

[0017] In some embodiments, each air inlet has a cashew-shaped structure, and the plurality of air inlets are evenly arranged at one end of the cylinder liner close to the intake piston, and the distance between each air inlet and the center plane of the cylinder liner is equal.

[0018] Specifically, in this embodiment, the air inlets are evenly circumferentially arranged on a horizontal plane at one end of the center plane of the cylinder liner. The shape of each air inlet is designed to be a cashew-shaped structure, and several air inlets form a spiral shape. Air enters the cylinder through the air inlets. Under the action of the spiral structure, the intake vortex can be effectively organized, and the formed vortex layer can push the exhaust gas out of the cylinder along the axis of the cylinder liner, thereby improving the scavenging efficiency.

[0019] In some embodiments, the plurality of exhaust ports are symmetrically arranged with the plane passing through the center axis of the cylinder liner as the center, and the distance between each exhaust port and the center plane of the cylinder liner is equal, wherein the inclined air ports are arranged on both sides of the middle straight air port.

[0020] Specifically, in this embodiment, the exhaust port is arranged circumferentially on the horizontal plane at the other end of the center plane of the cylinder liner, and the arrangement is as follows: Figure 2 As shown, the exhaust ports on both sides are symmetrical with the plane passing through the center axis of the cylinder liner as the center. They are composed of straight ports and ports with inclined angles, which can reduce the wall impact loss generated by the exhaust flow process, increase the exhaust port flow capacity, and thus improve the scavenging efficiency.

[0021] In some embodiments, the number of the fuel injectors is four, two fuel injectors are evenly arranged circumferentially on the center plane of the cylinder liner, and the spray hole of each fuel injector is an oblique hole arrangement.

[0022] Specifically, in this embodiment, the injectors are evenly arranged circumferentially at the center plane of the cylinder liner, and the spray hole structure of each injector is an inclined hole, and the spatial oil beam distribution formed is as follows: Figure 3 As shown, the problem of interference between the oil beams of multiple injectors can be effectively avoided. The design direction of the spatial oil beam injection is opposite to the rotation direction of the intake vortex formed in the cylinder. The air vortex motion is used to achieve rapid and sufficient mixing of oil and gas, improve combustion, and enhance combustion efficiency. At the same time, the high-temperature area formed by flame combustion can be kept away from the cylinder wall, thereby reducing the thermal load of the cylinder liner and reducing heat loss at the cylinder liner position.

[0023] Example 1 The intake and exhaust pistons each have a diameter of 120mm. Sixteen intake ports are evenly spaced along the center plane of one end of the cylinder liner, while fourteen exhaust ports are located along the center plane of the other end. These ports are arranged symmetrically around a plane passing through the center axis of the cylinder liner. The sixteen intake ports form a spiral pattern, effectively organizing the intake swirl flow as air enters the cylinder. The resulting swirl layer propels exhaust gases out of the cylinder along the cylinder liner axis, improving scavenging efficiency. The symmetrical exhaust ports on both sides each consist of a straight port and six ports at an angle, minimizing wall impact losses during exhaust flow and maximizing exhaust port flow capacity.

[0024] Four injectors are evenly arranged circumferentially on the center surface of the cylinder liner. The spray hole structure of each injector is an inclined hole. The fuel injected by multiple injectors forms a spatial oil beam. The formed spatial oil beam is as follows Figure 3 As shown, the problem of interference between the fuel beams of multiple injectors can be effectively avoided.

[0025] In this embodiment, the spatial oil beam injection direction is designed to be opposite to the rotation direction of the intake vortex formed in the cylinder, which can achieve rapid and sufficient mixing of oil and gas, improve combustion, and increase combustion efficiency. At the same time, the high-temperature area formed by flame combustion is kept away from the cylinder wall, thereby reducing the thermal load of the cylinder liner and reducing heat loss at the cylinder liner position.

[0026] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and description of the present invention.

[0027] The embodiments of the present application are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiments of the present application should be included in the scope of protection of this application.

Claims

1. An opposed piston two-stroke diesel engine intake swirl-combined injection combustion system, comprising a cylinder liner (1), an intake piston (3), an exhaust piston (4), and an injector (6), wherein the intake piston (3) and the exhaust piston (4) are correspondingly arranged in the cylinder liner (1) to form a combustion space, and a plurality of injectors (6) are evenly arranged circumferentially on the cylinder liner (1) at positions corresponding to the combustion space, characterized in that: An air inlet (2) and an air outlet (5) are circumferentially arranged at both ends of the cylinder liner (1), wherein a plurality of the air inlets (2) cooperate to form a spiral shape, and the air outlet (5) is composed of a straight air outlet and an inclined air outlet. External air enters the cylinder through the air inlet (2) to form an air intake vortex, and the formed vortex layer pushes the exhaust gas along the axis of the cylinder liner (1) to be discharged from the air outlet (5); The fuel injected by the multiple injectors (6) forms a spatial oil beam, and the injection direction of the spatial oil beam is opposite to the rotation direction of the intake vortex formed in the cylinder, so that the oil and gas are fully mixed and burned.

2. The system according to claim 1, wherein: Each of the air inlets (2) has a cashew-shaped structure, and a plurality of the air inlets (2) are evenly arranged at one end of the cylinder sleeve close to the air inlet piston (3), and the distance between each of the air inlets (2) and the center plane of the cylinder sleeve (1) is equal.

3. The system according to claim 1, wherein: The plurality of exhaust ports (5) are symmetrically arranged with a plane passing through the central axis of the cylinder liner (1) as the center, and the distance between each exhaust port (5) and the central plane of the cylinder liner (1) is equal, wherein the inclined air ports are arranged on both sides of the middle straight air port.

4. The system according to claim 1, wherein: The number of the fuel injectors (6) is four, two of the fuel injectors (6) are evenly circumferentially arranged at the center plane of the cylinder liner (1), and the spray hole of each fuel injector (6) is an oblique hole arrangement.

5. The system according to claim 1, wherein: The diameters of the intake piston (3) and the exhaust piston (4) are both in the range of 80 mm to 140 mm.

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