Opposed piston engine of integrated pre-combustion chamber piston structure and control method

Abstract

The invention relates to the technical field of internal combustion engines, and discloses an opposed piston engine of an integrated precombustion chamber piston structure and a control method, the opposed piston engine comprises an air cylinder, an air inlet piston, an exhaust piston, a spark plug and an ejector, an air inlet section and an exhaust section are arranged in the air cylinder, the air inlet section is provided with at least one air inlet, and the exhaust section is provided with at least one exhaust port; the air inlet piston is arranged on the air inlet section in a sliding mode, and an air inlet side combustion pit and an air inlet side pre-combustion pit are formed in the end face, facing the exhaust section, of the air inlet piston. The exhaust piston is arranged on the exhaust section in a sliding mode, an exhaust side combustion pit and an exhaust side pre-combustion pit are formed in the end face, facing the air inlet piston, of the exhaust piston, and when the air inlet piston and the exhaust piston get close to each other and move to the compression ending position, the air inlet side combustion pit and the exhaust side combustion pit form a main combustion cavity. According to the combustor, the flame propagation distance can be shortened, the flame diffusion speed can be increased, the combustion period can be shortened, and the combustion rate can be increased.

Description

Technical Field

[0001] This invention relates to the field of internal combustion engine technology, and in particular to an opposed piston engine with an integrated pre-combustion chamber piston structure and a control method thereof. Background Technology

[0002] Opposed piston engines eliminate the traditional cylinder head structure. The combustion chamber is formed by the top surface of the opposed pistons, and the injectors and spark plugs are both located on the cylinder wall, with both being side-mounted. This arrangement increases the fuel jet propagation distance and flame propagation distance, making the formation of the air-fuel mixture and flame propagation more difficult. Some existing opposed piston engines use a configuration with multiple injectors per cylinder to improve the uniformity of in-cylinder air-fuel mixture, but this increases cost and installation complexity. Others use multiple spark plugs, which increases cost and reduces cylinder liner strength. Still others use an additional pre-combustion chamber on the cylinder for ignition, which solves the problem of long flame propagation distance but also increases hot spots in the cylinder, making it prone to pre-ignition and other abnormal combustion phenomena. Furthermore, the pre-combustion chamber increases manufacturing costs. Therefore, it is necessary to optimize the design to improve air-fuel mixture and in-cylinder combustion, further enhancing the performance of opposed piston engines. Summary of the Invention The purpose of this invention is to provide an opposed piston engine with an integrated pre-combustion chamber piston structure and a control method thereon, so as to solve one or more technical problems existing in the prior art, and at least provide a beneficial option or create conditions.

[0003] The technical solution adopted to solve the above-mentioned technical problems is as follows: This invention provides an opposed piston engine with an integrated pre-combustion chamber piston structure, comprising: A cylinder has an internally connected intake section and an exhaust section, wherein the intake section has at least one intake port and the exhaust section has at least one exhaust port; An intake piston is slidably disposed in the intake section, and the end face of the intake piston facing the exhaust section is provided with an intake-side combustion recess and an intake-side pre-combustion recess. An exhaust piston is slidably disposed in the exhaust section. A combustion chamber with compressible volume is formed between the exhaust piston and the intake piston. The end face of the exhaust piston facing the intake piston is provided with an exhaust-side combustion recess and an exhaust-side pre-combustion recess. The exhaust-side combustion recess and the intake-side combustion recess are arranged opposite to each other. The exhaust-side pre-combustion recess and the intake-side pre-combustion recess are arranged opposite to each other. When the intake piston and the exhaust piston move closer to each other to the compression end position, the intake-side combustion recess and the exhaust-side combustion recess form the main combustion chamber, and the intake-side pre-combustion recess and the exhaust-side pre-combustion recess form the pre-combustion chamber. The main combustion chamber and the pre-combustion chamber are in communication. A spark plug is disposed on the cylinder wall of the cylinder between the intake section and the exhaust section, the spark plug being configured to ignite fuel in the pre-combustion chamber; An injector is disposed on the cylinder wall of the cylinder between the intake section and the exhaust section, the injector being configured to inject fuel into the combustion chamber.

[0004] The advantages of the opposed piston engine of the present invention are: This invention provides an intake-side combustion recess and an intake-side pre-combustion recess on the end face of the intake piston facing the exhaust piston, and an exhaust-side combustion recess and an exhaust-side pre-combustion recess on the end face of the exhaust piston facing the intake piston. The intake-side combustion recess and the exhaust-side combustion recess are positioned opposite each other, as are the intake-side pre-combustion recess and the exhaust-side pre-combustion recess. When the intake piston and the exhaust piston move close to each other to the end of the compression phase, the intake-side combustion recess and the exhaust-side combustion recess form the main combustion chamber, and the intake-side pre-combustion recess and the exhaust-side pre-combustion recess form the pre-combustion chamber. The main combustion chamber and the pre-combustion chamber are connected. When the spark plug ignites, the richer mixture in the pre-combustion chamber is ignited first, and then the high-temperature flame is injected into the main combustion chamber to ignite the mixture in the main combustion chamber, thereby increasing the combustion rate.

[0005] This invention uses intake and exhaust pistons to form the pre-combustion chamber and main combustion chamber, eliminating the need for a pre-combustion chamber on the cylinder. This shortens the flame propagation distance and, during purging, cools the intake-side and exhaust-side pre-combustion pits and the spark plug, solving the problems of high temperature in the traditional pre-combustion chamber and heat concentration at the spark plug head that easily leads to pre-ignition and other abnormal combustion issues. It also solves the problem of high temperature and fatigue in the part of the traditional pre-combustion chamber extending into the main combustion chamber. The placement of the intake-side and exhaust-side combustion pits facilitates the formation of strong tumble flow perpendicular to the cylinder axis during compression, promoting rapid mixing of the air-fuel mixture. Furthermore, in the later stages of compression, under the squeezing action of the intake and exhaust pistons, the vortex gradually breaks down into turbulence, further enhancing the mixing of the air-fuel mixture in the combustion chamber. This also helps to increase the turbulent kinetic energy in the combustion chamber, improve the flame diffusion speed, and shorten the combustion cycle.

[0006] As a further improvement to the above technical solution, the spark plug and the injector are located on the same cross section of the combustion chamber.

[0007] As a further improvement to the above technical solution, the injection port of the injector is close to the pre-combustion chamber, and the ignition electrode of the spark plug is located in the pre-combustion chamber.

[0008] As a further improvement to the above technical solution, the intake-side pre-combustion recess is located at the edge of the intake piston end face, and the exhaust-side pre-combustion recess is located at the edge of the exhaust piston end face.

[0009] As a further improvement to the above technical solution, the intake-side combustion recess is located at the center of the intake piston end face, and the exhaust-side combustion recess is located at the center of the exhaust piston end face.

[0010] As a further improvement to the above technical solution, the air intake direction of the air inlet is inclined along the circumference of the cylinder.

[0011] As a further improvement to the above technical solution, in the axial direction of the cylinder, the distance between the air intake port and the spark plug is greater than the distance between the exhaust port and the spark plug; and / or, the length of the air intake port is less than the length of the exhaust port.

[0012] As a further improvement to the above technical solution, at least one first jet hole is connected between the intake-side combustion recess and the intake-side pre-combustion recess; and / or, at least one second jet hole is connected between the exhaust-side combustion recess and the exhaust-side pre-combustion recess.

[0013] As a further improvement to the above technical solution, when the intake piston and the exhaust piston move close to each other to the end of the compression position, a piston gap is formed between the intake piston and the exhaust piston, and the piston gap connects the main combustion chamber and the pre-combustion chamber.

[0014] Furthermore, the present invention also proposes an engine control method applied to the aforementioned opposed piston engine, the control method comprising: By controlling the intake piston and the exhaust piston to move closer to each other, the engine enters the compression stroke, and the intake port and the exhaust port are closed in sequence, thus compressing and reducing the volume of the combustion chamber; In the early stage of the compression stroke, the injector is controlled to inject fuel into the combustion chamber to mix with air; In the later stages of the compression stroke, the injector is controlled to inject fuel into the combustion chamber again to increase the fuel concentration in the pre-combustion chamber; When the combustion chamber is compressed to its minimum volume, the spark plug is controlled to ignite the air-fuel mixture in the pre-combustion chamber. The flame generated by the combustion in the pre-combustion chamber ignites the fuel in the main combustion chamber, causing the engine to enter the power stroke. In the later stage of the power stroke, the intake piston and the exhaust piston move away from each other, and the exhaust port and the intake port are opened in sequence to perform scavenging.

[0015] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. Attached Figure Description

[0016] The present invention will be further described below with reference to the accompanying drawings and embodiments; Figure 1 This is a cross-sectional view of an embodiment of the opposed piston engine provided by the present invention, showing the intake piston and exhaust piston moving close to each other to the end of compression. Figure 2 This is a cross-sectional view of an embodiment of the cylinder provided by the present invention; Figure 3 yes Figure 1 A magnified view of part A in the middle; Figure 4 This is a cross-sectional view of an embodiment of the opposed piston engine provided by the present invention, in which the intake piston and exhaust piston move away from each other to the position at the end of the power stroke. Figure 5 This is an axial sectional view of the cylinder center position of an embodiment of the opposed piston engine provided by the present invention. Figure 6 This is a flowchart of an embodiment of the engine control method provided by the present invention; Icon labels: Cylinder 100; Intake section 110; Intake port 111; Exhaust section 120; Exhaust port 121; Cylinder liner support 130; Exhaust lower sealing surface 140; Exhaust upper sealing surface 150; Intake upper sealing surface 160; Intake lower sealing surface 170; First mounting seat 180; Second mounting seat 190; Intake piston 200; intake side combustion recess 210; intake side pre-combustion recess 220; first jet hole 230; Exhaust piston 300; exhaust side combustion recess 310; exhaust side pre-combustion recess 320; second jet hole 330; Spark plug 400; First mounting sleeve 410; Injector 500; Second mounting sleeve 510; Combustion chamber 600; Main combustion chamber 700; Pre-combustion chamber 800; Piston clearance 900. Detailed Implementation

[0017] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0018] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, etc., are based on the orientation or positional relationship shown in the drawings and are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0019] In the description of this invention, "multiple" refers to two or more. The use of "first" and "second" is for distinguishing technical features only and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features or their sequential relationship.

[0020] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0021] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are some embodiments of the present invention, not all embodiments.

[0022] Unlike four-stroke engines, which produce power every two crankshaft revolutions, two-stroke engines produce power every one crankshaft revolution. Therefore, two-stroke engines have stronger torque and higher power output per liter compared to four-stroke engines, resulting in better overall performance. The opposed-piston two-stroke engine eliminates the cylinder head and valve structure, with the opposed pistons positioned in the same cylinder. This significantly improves the engine's compactness, power-to-weight ratio, and operational smoothness, making it a promising candidate for future applications. However, because the opposed-piston engine eliminates the traditional cylinder head structure, the combustion chamber is formed by the top surface of the opposed pistons, and the injectors and spark plugs are located on the cylinder wall. This arrangement increases the fuel jet propagation distance and flame propagation distance, making the formation of the air-fuel mixture and flame propagation more challenging.

[0023] Opposed piston engines require side-mounted injectors, resulting in long-range fuel jets and inefficient space utilization. Meanwhile, two-stroke engines suffer from poor in-cylinder fuel-air mixing due to narrow fuel injection windows and short fuel-air mixing time. Some opposed piston engines employ a multi-injector configuration per cylinder to improve in-cylinder fuel-air mixing uniformity, but this increases both cost and layout complexity.

[0024] Meanwhile, in opposed-piston engines, the spark plugs are positioned to the side, resulting in a longer flame propagation distance. Furthermore, the presence of in-cylinder swirl causes the spark plug ignition to propagate circumferentially along the cylinder liner, further increasing the flame propagation distance. Using multiple spark plugs increases the difficulty of placement, raises costs, and reduces cylinder liner strength. While the pre-combustion chamber ignition scheme can solve the problem of long flame propagation distance, it also increases hot spots in the cylinder, making it prone to pre-ignition and other abnormal combustion phenomena. Additionally, the pre-combustion chamber increases manufacturing costs.

[0025] Therefore, this invention proposes an opposed piston engine with an integrated pre-combustion chamber piston structure to improve the problems of air-fuel mixing and in-cylinder combustion.

[0026] like Figures 1 to 5 As shown, the opposed piston engine of the present invention includes: a cylinder 100, an intake piston 200, an exhaust piston 300, a spark plug 400, and an injector 500.

[0027] Among them, such as Figure 1 and 2 As shown, the cylinder 100 has an inlet section 110 and an exhaust section 120 that are connected inside. In this embodiment, the cylinder 100 is cylindrical, and the exhaust section 120 and the inlet section 110 are arranged in a left-right sequence.

[0028] like Figure 2 As shown, at least one air inlet 111 is provided on the cylinder wall of the intake section 110, and at least one exhaust port 121 is provided on the cylinder wall of the exhaust section 120. In order to increase the intake and exhaust volume, multiple air inlets 111 and exhaust ports 121 are provided in this embodiment. Multiple air inlets 111 are distributed along the circumference of the intake section 110, and multiple exhaust ports 121 are distributed along the circumference of the exhaust section 120.

[0029] like Figure 2 As shown, the outer side of the cylinder 100 in this embodiment has a stepped layout. From left to right, the outer side of the cylinder 100 is provided with a cylinder liner support 130, an exhaust lower sealing surface 140, an exhaust upper sealing surface 150, an intake upper sealing surface 160, and an intake lower sealing surface 170. Multiple exhaust ports 121 are located between the exhaust lower sealing surface 140 and the exhaust upper sealing surface 150, while multiple intake ports 111 are located between the intake upper sealing surface 160 and the intake lower sealing surface 170. The cylinder liner support 130 is used for the installation and positioning of the cylinder 100, while the exhaust lower sealing surface 140, exhaust upper sealing surface 150, intake upper sealing surface 160, and intake lower sealing surface 170 are used for sealing the gas passage.

[0030] Furthermore, the intake direction of the air inlet 111 is inclined along the circumference of the cylinder 100 to form a vortex intake.

[0031] like Figure 4As shown, the intake piston 200 is slidably disposed in the intake section 110 in the left-right direction, and the exhaust piston 300 is slidably disposed in the exhaust section 120 in the left-right direction, so that a combustion chamber 600 with compressible volume is formed between the exhaust piston 300 and the intake piston 200.

[0032] Among them, such as Figure 1 and Figure 3 As shown, the intake piston 200 has an intake-side combustion recess 210 and an intake-side pre-combustion recess 220 on its end face facing the exhaust piston 300, and the exhaust piston 300 has an exhaust-side combustion recess 310 and an exhaust-side pre-combustion recess 320 on its end face facing the intake piston 200. In the left-right direction, the exhaust-side combustion recess 310 is arranged opposite to the intake-side combustion recess 210, and the exhaust-side pre-combustion recess 320 is arranged opposite to the intake-side pre-combustion recess 220.

[0033] like Figure 1 and Figure 3 As shown, when the intake piston 200 and the exhaust piston 300 move close to each other to the end of the compression position, it can be understood that when the volume of the combustion chamber 600 is at its minimum, the intake-side combustion recess 210 and the exhaust-side combustion recess 310 form the main combustion chamber 700, and the intake-side pre-combustion recess 220 and the exhaust-side pre-combustion recess 320 form the pre-combustion chamber 800, and the main combustion chamber 700 and the pre-combustion chamber 800 are connected.

[0034] like Figure 1 and Figure 3 As shown, in this embodiment, the spark plug 400 is disposed on the cylinder wall of the cylinder 100 between the intake section 110 and the exhaust section 120. The spark plug 400 is configured to ignite the fuel in the pre-combustion chamber 800. When the intake piston 200 and the exhaust piston 300 move close to each other to the end of the compression position, the positions of the pre-combustion chamber 800 and the spark plug 400 are correspondingly set.

[0035] like Figure 5 As shown, the injector 500 is located on the cylinder wall of the cylinder 100 between the intake section 110 and the exhaust section 120, and the injector 500 is configured to inject fuel into the combustion chamber 600.

[0036] like Figure 2 and Figure 5 As shown, the cylinder 100 in this embodiment is provided with a first mounting seat 180 and a second mounting seat 190. The spark plug 400 is mounted on the first mounting seat 180 through the first mounting sleeve 410, and the injector 500 is mounted on the second mounting seat 190 through the second mounting sleeve 510.

[0037] In some embodiments, the distance between the intake port 111 and the spark plug 400 in the axial direction of the cylinder 100 is greater than the distance between the exhaust port 121 and the spark plug 400. Alternatively, the length of the intake port 111 is less than the length of the exhaust port 121. This allows the exhaust port 121 to be opened earlier during the power stroke as the exhaust piston 300 and the intake piston 200 move away from each other, allowing for free exhaust of exhaust gas and releasing the cylinder pressure. When the cylinder pressure is lower than the intake pressure, the intake port 111 opens, initiating the scavenging process. Fresh air is introduced through a strong vortex ratio, forming a high-speed rotating air mass at the head of the intake piston 200. This air mass propels the exhaust gas out. Simultaneously, the air mass is a vortex air mass with small-scale planar movement, reducing exhaust gas mixing.

[0038] like Figure 1 As shown, in the later stage of the compression stroke, when the intake piston 200 and the exhaust piston 300 move closer to each other to the end of the compression position, the intake-side combustion recess 210 and the exhaust-side combustion recess 310 form the main combustion chamber 700, and the intake-side pre-combustion recess 220 and the exhaust-side pre-combustion recess 320 form the pre-combustion chamber 800. The main combustion chamber 700 and the pre-combustion chamber 800 are connected. When the spark plug 400 ignites, it first ignites the richer mixture in the pre-combustion chamber 800, and then the high-temperature flame is injected into the main combustion chamber 700 to ignite the mixture in the main combustion chamber 700, thereby increasing the combustion rate.

[0039] The present invention forms the pre-combustion chamber 800 and the main combustion chamber 700 by means of the intake piston 200 and the exhaust piston 300, eliminating the need to set the pre-combustion chamber 800 on the cylinder 100, shortening the flame propagation distance, and also improving the structural strength of the cylinder 100 and improving the space utilization.

[0040] Furthermore, the residual exhaust gas in the intake-side pre-combustion recess 220 and the exhaust-side pre-combustion recess 320 will be removed under the scavenging action, which solves the problem of difficult scavenging and high residual exhaust gas coefficient in the passive pre-combustion chamber 800 of traditional two-stroke engines. During scavenging, fresh air can cool the intake-side pre-combustion recess 220, the exhaust-side pre-combustion recess 320 and the spark plug 400, which solves the problem of high temperature in the traditional pre-combustion chamber 800 and the problem of heat concentration at the spark plug 400 head that easily causes pre-ignition and other abnormal combustion problems. At the same time, it also solves the problem of high temperature and easy fatigue in the part of the traditional pre-combustion chamber 800 that extends into the main combustion chamber.

[0041] During the compression stroke, the placement of the intake-side combustion recess 210 and the exhaust-side combustion recess 310 helps to form a strong tumble flow that is perpendicular to the axis of the cylinder 100, which is conducive to the rapid mixing of the air-fuel mixture. Furthermore, in the later stage of compression, under the squeezing action of the squeezing surfaces of the intake piston 200 and the exhaust piston 300, the vortex gradually breaks down to form turbulence, which further enhances the mixing of the air-fuel mixture in the combustion chamber 600. At the same time, it also helps to increase the turbulent kinetic energy in the combustion chamber 600, increase the flame diffusion speed, and shorten the combustion cycle.

[0042] In this embodiment, the spark plug 400 and the injector 500 are located on the same cross section of the combustion chamber 600, and the injection port of the injector 500 is close to the pre-combustion chamber 800. The ignition electrode of the spark plug 400 is located in the pre-combustion chamber 800. The pre-combustion chamber 800 can be replenished with fuel by a secondary injection method to ensure that a richer mixture is formed in the intake side pre-combustion pit 220, the exhaust side pre-combustion pit 320 and near the spark plug 400.

[0043] like Figure 1 and Figure 3 As shown, in this embodiment, the intake-side pre-combustion recess 220 is located at the edge of the end face of the intake piston 200, and the exhaust-side pre-combustion recess 320 is located at the edge of the end face of the exhaust piston 300, so that the pre-combustion chamber 800 is close to the spark plug 400, so as to facilitate the spark plug 400 to ignite the mixture in the pre-combustion chamber 800.

[0044] In this embodiment, the intake-side combustion recess 210 is located at the center of the end face of the intake piston 200, and the exhaust-side combustion recess 310 is located at the center of the end face of the exhaust piston 300. This makes the main combustion chamber 700 located at the center between the intake piston 200 and the exhaust piston 300, so that the exhaust piston 300 and the intake piston 200 are subjected to uniform force during power generation.

[0045] Furthermore, such as Figure 3 As shown, at least one first jet hole 230 is connected between the intake-side combustion recess 210 and the intake-side pre-combustion recess 220; and / or, at least one second jet hole 330 is connected between the exhaust-side combustion recess 310 and the exhaust-side pre-combustion recess 320, thereby achieving a multi-point ignition effect of the pre-combustion chamber 800 on the main combustion chamber 700.

[0046] Furthermore, such as Figure 3As shown, when the intake piston 200 and the exhaust piston 300 move close to each other to the end of the compression position, a piston gap 900 is formed between the intake piston 200 and the exhaust piston 300. The piston gap 900 connects the main combustion chamber 700 and the pre-combustion chamber 800. Then, the high-temperature flame can be injected into the main combustion chamber 700 through the first jet hole 230, the second jet hole 330 and the piston gap 900, forming multi-source ignition in the main combustion chamber 700, improving the combustion rate, effectively reducing manufacturing costs, and solving the problem of difficult arrangement of multiple spark plugs 400.

[0047] When the combustion chamber 600 has the smallest volume, the end face distance between the intake piston 200 and the exhaust piston 300 is 0.8 to 1.5 mm.

[0048] In addition, such as Figure 6 As shown, the present invention also proposes an engine control method, applied to the aforementioned opposed piston engine, the control method comprising: Step S100: Control the intake piston 200 and exhaust piston 300 to move closer to each other, so that the engine enters the compression stroke, and the intake port 111 and exhaust port 121 are closed in sequence, and the volume of the combustion chamber 600 is compressed and reduced. Step S200: In the early stage of the compression stroke, the injector 500 is controlled to inject fuel into the combustion chamber 600 to mix with air; Step S300: In the later stage of the compression stroke, control the injector 500 to inject fuel into the combustion chamber 600 again to increase the fuel concentration in the pre-combustion chamber 800; Step S400: When the combustion chamber 600 is compressed to its minimum volume, the spark plug 400 is controlled to ignite the air-fuel mixture in the pre-combustion chamber 800. The flame generated by the combustion in the pre-combustion chamber 800 ignites the fuel in the main combustion chamber 700, causing the engine to enter the power stroke. Step S500: In the later stage of the power stroke, the intake piston 200 and the exhaust piston 300 move away from each other, and the exhaust port 121 and the intake port 111 are opened in sequence to perform scavenging.

[0049] In steps S100 and S500, the exhaust piston 300 is designed to be ahead of the intake piston 200 in phase. When the intake piston 200 is at top dead center, the exhaust piston 300 has already moved downward. During the power stroke, the exhaust piston 300 and the intake piston 200 move downward respectively, and the exhaust port 121 opens in advance. During the free exhaust process, the exhaust gas is released, releasing the cylinder pressure. When the cylinder pressure is lower than the intake pressure, the intake port 111 opens, and the scavenging process begins. Fresh air is introduced through a strong vortex ratio. Before entering the compression stroke, the intake port 111 closes first, and then the exhaust port 121 closes.

[0050] The injector 500 of the present invention adopts a two-stage injection strategy. In step S200, the injector 500 is controlled to perform a first injection, which is the main injection and begins immediately after the exhaust port 121 is closed, aiming to obtain a uniform mixture. In step S300, the injector 500 is controlled to perform a second injection, which is an auxiliary injection in the later stage of compression. It adopts the minimum achievable injection pulse width, aiming to form a richer mixture in the pre-combustion chamber 800 and near the spark plug 400.

[0051] In step S400, when the spark plug 400 ignites, it first ignites the richer mixture in the pre-combustion chamber 800, and then injects the high-temperature flame into the main combustion chamber 700 through the first jet hole 230, the second jet hole 330, or the piston gap 900, forming multi-source ignition in the main combustion chamber 700, increasing the combustion rate, and achieving the effect of multi-point ignition by multiple spark plugs 400. This effectively reduces manufacturing costs and solves the problem of difficult arrangement of multiple spark plugs 400.

[0052] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0053] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. An opposed-piston engine incorporating an integrated pre-chamber piston structure, characterized by, The opposed-piston engine comprises: a cylinder having an intake section and an exhaust section connected to each other, the intake section being provided with at least one intake port, and the exhaust section being provided with at least one exhaust port; an intake piston slidingly arranged in the intake section, an end surface of the intake piston facing the exhaust section being provided with an intake-side combustion recess and an intake-side pre-combustion recess; an exhaust piston slidingly arranged in the exhaust section, the exhaust piston and the intake piston forming a combustion chamber having a volume that is compressibly variable therebetween, an end surface of the exhaust piston facing the intake piston being provided with an exhaust-side combustion recess and an exhaust-side pre-combustion recess, the exhaust-side combustion recess being arranged opposite to the intake-side combustion recess, and the exhaust-side pre-combustion recess being arranged opposite to the intake-side pre-combustion recess, the intake-side combustion recess and the exhaust-side combustion recess forming a main combustion chamber, and the intake-side pre-combustion recess and the exhaust-side pre-combustion recess forming a pre-combustion chamber, when the intake piston and the exhaust piston are moved close to each other to a compression end position; a spark plug arranged in a cylinder wall of the cylinder between the intake section and the exhaust section, the spark plug being configured to ignite fuel in the pre-combustion chamber; and an injector arranged in the cylinder wall of the cylinder between the intake section and the exhaust section, the injector being configured to inject fuel into the combustion chamber.

2. The opposed-piston engine according to claim 1, wherein: the spark plug and the injector are arranged on the same cross section of the combustion chamber.

3. The opposed-piston engine according to claim 2, wherein: an injection port of the injector is located close to the pre-combustion chamber, and an ignition electrode of the spark plug is arranged in the pre-combustion chamber.

4. The opposed-piston engine according to claim 3, wherein: the intake-side pre-combustion recess is located at a rim of the end surface of the intake piston, and the exhaust-side pre-combustion recess is located at a rim of the end surface of the exhaust piston.

5. The opposed-piston engine according to claim 1, wherein: the intake-side combustion recess is arranged at a center of the end surface of the intake piston, and the exhaust-side combustion recess is arranged at a center of the end surface of the exhaust piston.

6. The opposed-piston engine according to claim 1, wherein: an intake direction of the intake port is inclined along a circumferential direction of the cylinder.

7. The opposed-piston engine according to claim 1, wherein: in an axial direction of the cylinder, a distance from the intake port to the spark plug is greater than a distance from the exhaust port to the spark plug; and / or, a length of the intake port is smaller than a length of the exhaust port.

8. The opposed-piston engine according to claim 1, wherein: at least one first jet hole is communicated between the intake-side combustion recess and the intake-side pre-combustion recess; and / or, at least one second jet hole is communicated between the exhaust-side combustion recess and the exhaust-side pre-combustion recess.

9. The opposed-piston engine according to claim 1, wherein: When the intake piston and the exhaust piston move towards each other to the compression end position, a piston gap is formed between the intake piston and the exhaust piston, and the piston gap is communicated between the main combustion chamber and the pre-combustion chamber.

10. A control method of an engine characterized by comprising: The control method is applied to the opposed-piston engine according to any one of claims 1 to 9, and the control method comprises: controlling the intake piston and the exhaust piston to move towards each other to enter the compression stroke, and sequentially closing the intake port and the exhaust port, and the volume of the combustion chamber is compressed to be smaller; in the early stage of the compression stroke, controlling the injector to inject fuel into the combustion chamber to mix with air; in the late stage of the compression stroke, controlling the injector to inject fuel into the combustion chamber again to increase the fuel concentration in the pre-combustion chamber; when the combustion chamber is compressed to the smallest volume, controlling the spark plug to ignite the mixture in the pre-combustion chamber to burn, and the flame generated by the combustion in the pre-combustion chamber ignites the fuel in the main combustion chamber to burn, so that the engine enters the power stroke; in the late stage of the power stroke, the intake piston and the exhaust piston move away from each other, and the exhaust port and the intake port are sequentially opened to perform scavenging.

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