A two-stage combustion six-stroke engine

Abstract

This invention discloses a two-stage combustion six-stroke engine, comprising a single-cylinder engine body, a fuel injector, and a valve train unit disposed on the cylinder head; the valve train unit includes a gas reservoir, a first intake port, a second intake port, and a gas injector, used to compress and store gas and release gas; the center of the injector nozzle is located on a first axis; the centers of the gas reservoir and the injector nozzle are located away from the first axis to form tumble flow in the combustion chamber; the six-stroke engine utilizes the gas reservoir and part of the first intake port to achieve two consecutive compression and combustion of the working fluid in the same cylinder; moreover, in the second compression and combustion power stroke, the gas injected into the combustion chamber by the gas injector interacts with the in-cylinder airflow formed near the gas reservoir, forming enhanced tumble flow in the combustion chamber.

Description

Technical Field

[0001] This invention belongs to the field of high power density engines, specifically relating to a two-stage combustion six-stroke engine with a valve train unit mounted on the cylinder head. Background Technology

[0002] High-power-density engines represent a crucial development direction in the internal combustion engine field. Their core objective is to maximize power output within limited displacement, size, and mass constraints to meet the increasingly urgent demands of modern transportation, specialized machinery, and distributed energy systems for miniaturized, lightweight, and highly efficient power units. Current methods for increasing engine power density include turbocharging, direct injection, and high-strength structural design. However, in practical applications, these methods result in higher combustion pressures and pressure rise rates, increasing the load on various engine components and reducing engine lifespan.

[0003] To improve thermal efficiency while partially alleviating the aforementioned problems, researchers proposed the concept of a six-stroke engine. The basic idea is to add two auxiliary strokes after the traditional four strokes of intake, compression, power, and exhaust, forming a new thermodynamic cycle. A typical implementation involves injecting water into the still-hot cylinder after the exhaust stroke. The water rapidly evaporates into steam in the hot cylinder, expanding dramatically and pushing the piston downwards again to perform work—this is the fifth stroke (second power stroke), followed by a second exhaust stroke (sixth stroke). This process recovers residual waste heat in the cylinder, theoretically improving efficiency. However, this technical approach has significant drawbacks: it requires extremely high purity water to prevent scaling, corrosion, or damage to the water injectors under high temperature and pressure; simultaneously, the condensation of water vapor at low temperatures can cause cylinder block corrosion and increases the complexity of aftertreatment requirements. These factors make this technology face significant challenges in practical applications, resulting in high costs, difficulty in guaranteeing reliability, and limited widespread adoption.

[0004] To further improve the practicality and performance of six-stroke engines, existing technologies have explored a secondary combustion approach that does not rely on water. CN120798520A discloses a two-stage combustion six-stroke engine with combined intake. This technical solution adds an air reservoir to the traditional intake manifold and, through ingenious design of the opening and closing sequence of the intake valve, exhaust valve, and air reservoir control valve, achieves two independent intake, fuel injection, and combustion power processes within one working cycle. Its working principle is as follows: during the exhaust stroke after the first combustion power stroke, the pressure difference between the cylinder and the air reservoir forces some exhaust gas or fresh air into the air reservoir for temporary storage; in the subsequent second intake stroke, the stored gas is drawn into the cylinder, providing the working fluid for the second combustion. This engine does not require an external air pump; it relies solely on the pressure difference generated by the engine itself to complete air storage and secondary intake, solving the problems of insufficient air intake during the secondary combustion stage, poor fuel-air mixture quality, incomplete combustion, and limited efficiency improvement inherent in existing six-stroke engines. Summary of the Invention

[0005] The present invention addresses the shortcomings of existing technologies by providing a two-stage combustion six-stroke engine. In this single-cylinder engine, the gas reservoir and its air passage connecting to the combustion chamber are arranged on the cylinder head, and the gas injector is positioned on the cylinder head offset from the fuel injector and at a certain angle to the cylinder head axis.

[0006] A two-stage combustion six-stroke engine includes a single-cylinder engine body and a fuel injector. The single-cylinder engine body includes a cylinder head, a cylinder block, a piston, an intake manifold, an intake valve, an exhaust manifold, and an exhaust valve. The piston reciprocates within the cylinder body formed by the cylinder head and the cylinder block. The space enclosed by the three components constitutes a combustion chamber. The six-stroke engine also includes a valve train unit integrated on the cylinder head. The gas distribution unit includes a gas storage tank, a first gas passage, a second gas passage, and a gas injector, forming a gas storage and injection circuit to achieve compressed gas storage and gas release. One end of the first air passage is connected to the combustion chamber, and the other end is connected to the air storage tank. An air storage valve is provided at the end of the passage that connects to the combustion chamber. One end of the second air passage is connected to the gas storage tank, and the other end is connected to the combustion chamber through a gas injector, with the injection port of the gas injector extending into the combustion chamber; Wherein, the center of the injector nozzle is located on the first axis; the first axis is perpendicular to the cylinder head and intersects the cylinder head at the center; since the usable area of ​​the cylinder head is limited and the lower half of the cylinder head is arranged with a lubrication area, the center of the gas reservoir valve and the injection port of the gas injector is located away from the first axis to form tumble in the combustion chamber. The six-stroke engine utilizes an air tank and part of the first air passage to achieve two consecutive compressions and combustions of the working fluid in the same cylinder. In one working cycle, it completes one intake stroke, the first compression and air storage stroke, the first combustion power stroke, the exhaust and air replenishment stroke, the second compression and combustion power stroke, and the second exhaust stroke. Moreover, during the second compression and combustion power stroke, the gas injected into the combustion chamber by the gas injector interacts with the in-cylinder airflow formed near the gas reservoir valve, creating enhanced tumble motion within the combustion chamber.

[0007] Furthermore, the cylinder head is provided with an intake valve, an exhaust valve, and a fuel injector, with the fuel injector located between the intake valve and the exhaust valve and arranged at the center of the cylinder head.

[0008] Furthermore, the axis of the injector forms an angle of 15-25° with the axis of the cylinder head.

[0009] Furthermore, the axis of the gas injector forms an angle of 15-25° with the axis of the cylinder head.

[0010] Furthermore, the gas injector is arranged near the gas storage valve.

[0011] Preferably, the diameter ratio of the air storage valve to the air intake valve is 1:6.

[0012] Furthermore, a one-way valve is provided in the first air passage, which allows gas to flow from the combustion chamber to the gas tank; and the one-way valve is located close to the cylinder head, so that the area in the first air passage from the one-way valve to the gas tank contains the gas from the combustion chamber.

[0013] Furthermore, the working process of the two-stage combustion six-stroke engine includes the following strokes performed sequentially: Intake stroke: The piston moves downward from top dead center, opening the intake valve and closing the exhaust valve, allowing fresh air to enter the combustion chamber; First compression and storage stroke: The piston moves upward from bottom dead center, compressing the gas in the combustion chamber, and the intake and exhaust valves are closed; when the piston moves up to 3 / 4 of its stroke from the top of the cylinder head, the storage valve is opened, and part of the gas in the combustion chamber is stored in the storage tank and part of the first intake port; First combustion power stroke: The gas reservoir valve is closed, the fuel injector injects fuel into the combustion chamber for the first time, the air-fuel mixture is compressed and ignited, pushing the piston downward to output power, completing the first combustion power stroke; Exhaust and Injection Strokes: The exhaust valve is opened and the intake valve is closed, and the exhaust gas from the first combustion is discharged through the exhaust passage; when the piston approaches top dead center, the exhaust valve is closed, and the gas injector injects gas from the gas tank and the first intake passage into the combustion chamber to replenish the working fluid; The second compression and combustion power stroke: When all the gas in the gas tank is emptied, the exhaust valve is closed before the piston reaches top dead center. The gas injector and fuel injector open simultaneously to perform the second fuel injection operation. The mixture is compressed and ignited, pushing the piston downward to output power and complete the second combustion power stroke. Second exhaust stroke: After combustion ends, the exhaust valve opens, the piston moves upward, and the exhaust gas produced by the second combustion is discharged, completing the cycle.

[0014] The beneficial effects of this invention are as follows: The six-stroke engine of this invention places the gas reservoir and its air passage connecting to the combustion chamber on the cylinder head, which reduces the loss of high-temperature, high-pressure gas during the gas storage process and improves the engine's gas storage efficiency. Compared to the prior art method of placing the gas reservoir in the intake manifold, this reduces leakage of high-temperature, high-pressure gas during compression, storage, and release, increases the air-fuel mixture concentration before the second combustion, improves the quality of the air-fuel mixture, and enhances the efficiency and stability of the second combustion.

[0015] A gas reservoir valve is placed at the connection between the first intake manifold and the cylinder head. This serves two purposes: firstly, it improves the sealing of the gas storage system, reducing leakage of high-temperature, high-pressure gases; secondly, it ensures that the compression ratio remains constant during engine operation, preventing changes in compression ratio from affecting engine efficiency. Furthermore, a one-way valve is placed on the first intake manifold, which can be triggered at lower pressures to open, allowing high-temperature, high-pressure gases to enter the gas reservoir more smoothly, reducing the negative work done by the engine during compression. The one-way valve has a higher pressure resistance. Because the stored high-temperature, high-pressure gases are at high pressure, a gas reservoir valve alone is insufficient to guarantee the sealing of the gas reservoir; adding a one-way valve improves the sealing of the intake manifold, reducing leakage of high-temperature, high-pressure gases.

[0016] The gas injector is positioned off-center from the fuel injector on the cylinder head and at a certain angle to the cylinder head axis. This improves the degree of fuel-air mixing before the second combustion power stroke, thereby increasing combustion efficiency. The addition of the gas injector allows the compression and release processes of the gas storage system to be carried out independently, preventing leakage of some compressed gas due to the delayed closing of the exhaust valve when releasing the stored high-temperature and high-pressure gas. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of the two-stage combustion six-stroke engine of the present invention; Figure 2 yes Figure 1 The cylinder head of the engine shown is viewed from below. Figures 3a-3j This is a schematic diagram of the operation of the six-stroke engine at each stage; Figure 4 Show the angle between the injector axis and the cylinder head axis. And the angle between the axis of the gas injector and the axis of the cylinder head. .

[0018] in, 1: Cylinder head; 2: Cylinder block; 3: Piston; 4: Intake manifold; 5: Exhaust manifold; 6: Intake valve; 7: Reservoir valve; 8: Injector; 9: Gas injector; 10: Exhaust valve; 11: Check valve; 12: Reservoir; 13: First intake manifold; 14: Second intake manifold; L1: First shaft. Detailed Implementation

[0019] To make the objectives, technical solutions, beneficial effects, and significant advancements of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings provided in the examples of the present invention. Obviously, all the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] In the description of this application, unless otherwise expressly specified and limited, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance; the term "multiple" refers to two or more; unless otherwise specified or explained, the terms "connected," "fixed," etc., should be interpreted broadly. For example, "connected" can be a fixed connection, a detachable connection, an integral connection, or an electrical connection; "connected" can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0021] like Figure 1-2As shown, a two-stage combustion six-stroke engine includes a single-cylinder engine body, a fuel injector 8, and a valve train. The single-cylinder engine body includes a cylinder head 1, a cylinder block 2, a piston 3, an intake manifold 4, an intake valve 6, an exhaust manifold 5, and an exhaust valve 10. The piston 3 can reciprocate within the cylinder body formed by the cylinder head 1 and the cylinder block 2, and the space formed by the cylinder head 1, the cylinder block 2, and the piston 3 is the combustion chamber, providing a sealed and stable working environment for gas compression and energy output. The cylinder head 1 is equipped with an intake valve 6, an exhaust valve 10, and a fuel injector 8. The fuel injector 8 is centrally located between the intake valve 6 and the exhaust valve 10, and is connected to an external fuel system via a pipeline (the fuel system is not the focus of this invention; an existing fuel system can be used, and will not be described in detail here). The fuel injector 8 is arranged at the center of the cylinder head to inject fuel into the combustion chamber before the two power strokes of combustion. This arrangement allows the fuel to be evenly diffused to all areas of the combustion chamber after injection, ensuring complete combustion. The intake valve 6 and the exhaust valve 10 are respectively installed in the intake duct 4 and the exhaust duct 5.

[0022] The valve train, mounted on the cylinder head 1, is a key mechanism for realizing gas flow, storage, and injection. It includes a gas tank 12, a first intake port 13, and a second intake port 14. The gas tank 12 has a gas storage chamber, which serves as the core for storing high-temperature and high-pressure gases on the cylinder head 1. It is bidirectionally connected to the combustion chamber through the first intake port 13 and the second intake port 14. On the one hand, it collects the high-temperature and high-pressure gases generated during compression through the first intake port 13. On the other hand, it releases the stored gases back to the combustion chamber during the fifth stroke (the second compression and combustion stage) through the second intake port 14 and the gas injector 9.

[0023] The first air passage 13 and the second air passage 14 are respectively connected to the combustion chamber and the air tank 12. The ends of the first air passage 13 and the second air passage 14 that connect to the combustion chamber are located on the cylinder head 1, which is used to realize the functions of compressing and storing gas and releasing gas. Moreover, an air storage valve 7 is provided at the end of the first air passage 13 located on the cylinder head 1, which is used to control the opening and closing of the first air passage 13. Furthermore, the air storage valve 7 is minimized as much as possible while meeting the gas flow cross-sectional area requirements, with a diameter ratio of 1:6 to the intake valve, in order to save the limited installation space on the cylinder head 1, avoid layout interference with core components such as the fuel injector 8 and the gas injector 9, and at the same time, the small size design can shorten the residual space of the first air passage 13 after the air storage valve 7 is closed, reduce the amount of high temperature and high pressure gas remaining in the first air passage 13, and improve the gas storage efficiency of the air tank 12.

[0024] A one-way valve 11 is installed in the first air passage 13 to prevent gas in the gas tank 12 from flowing back into the combustion chamber. The one-way valve, relying on its high pressure-bearing capacity, ensures the airtightness of the gas tank 12, allowing gas to flow only from the combustion chamber to the gas tank 12, reducing the leakage of high-temperature, high-pressure gas into the combustion chamber through the gas storage valve 7. Furthermore, the one-way valve 11 is positioned on the first air passage 13 near the cylinder head 1, allowing more space in the first air passage 13 facing the gas tank 12 to store a portion of the high-temperature, high-pressure gas from the combustion chamber, reducing leakage of high-temperature, high-pressure gas from the first air passage 13 into the combustion chamber, and also reducing the volume of the gas tank 12.

[0025] The second air passage 14 is located at the end of the cylinder head 1 and is equipped with a gas injector 9. The injection port of the gas injector 9 extends into the combustion chamber to directly inject high-pressure gas from the gas tank 12 into the combustion chamber. The components of the valve train are arranged and sealed together to form a complete gas control circuit.

[0026] like Figure 2 As shown, the center lines of the intake valve 6, exhaust valve 10, and injector 8 are located on the same straight line, i.e., the first axis L1. This layout is beneficial for stable intake flow and fuel-air mixing during the traditional four-stroke operating phase (initial intake-compression-power-exhaust), ensuring efficient execution of the first combustion stroke. Since the lower part of the cylinder head is a lubrication area, it is equipped with an additional lubrication system. The reservoir valve 7 is located on the cylinder head 1 away from the intake manifold 4 and exhaust manifold 5, avoiding structural interference between the installation of the reservoir valve 7 and the intake manifold, and ensuring smooth intake and exhaust.

[0027] like Figure 4 As shown, the angle between the centerline of the injector 8 and the centerline of the cylinder head 1 is degrees. The angle The angle is 15-25°, which guides the fuel mist to form a specific diffusion direction, and cooperates with the intake vortex or tumble motion in the combustion chamber to optimize the fuel-air mixture effect in advance during the first combustion.

[0028] The injection port of the gas injector 9 is located near the gas reservoir 7, with the two as close as possible to avoid affecting the shape of the gas reservoir 12 due to a large distance between them. Furthermore, the angle formed between the central axis of the gas injector 9 and the central axis of the cylinder head 1 is... The range is 15-25°, which, in conjunction with the offset angle of injector 8, improves the degree of air-fuel mixture before the second combustion power stroke.

[0029] The center point of the injection port of the gas storage valve 7 and the gas injector 9 is far away from the first axis L1. This arrangement can form a tumble in the combustion chamber during the fifth stroke stage (the second compression and combustion stage), which promotes the rapid mixing of the high-pressure air injected twice with the mixture in the combustion chamber.

[0030] like Figures 3a-3j As shown, the working process of the two-stage combustion six-stroke engine includes the following working stages: First stroke: Intake stroke like Figure 3a As shown, the piston starts to move downward from the top dead center. At this time, the intake valve 6 is opened and the exhaust valve 10 is closed. The piston 3 moves downward. The downward movement of the piston 3 will create a certain vacuum negative pressure in the combustion chamber. With the help of this negative pressure, fresh air from the outside enters the combustion chamber through the intake manifold, providing enough air for the subsequent combustion power stroke.

[0031] Second stroke: First compression and gas storage stroke like Figure 3b As shown, the intake valve 6 is closed and the exhaust valve 10 remains closed, forming a closed space in the combustion chamber. The piston 3 moves upward from the bottom dead center, compressing the air in the combustion chamber during the compression stroke, thus compressing the gas in the combustion chamber and increasing its pressure and temperature. like Figure 3c As shown, when the piston moves upward to the position 3 / 4 away from the top of the cylinder head, the air in the combustion chamber has reached a certain pressure and temperature. When the gas storage valve 7 is opened, under the combined action of the pressure difference and the upward movement of the piston 3, a portion of the high-temperature and high-pressure gas in the combustion chamber flows into the gas storage tank 12. At this time, the high-temperature and high-pressure gas is stored in the gas storage tank 12 and part of the first gas passage 13.

[0032] Third stroke: The first combustion and power stroke like Figure 3d As shown, when piston 3 reaches near top dead center, injector 8 injects fuel into the combustion chamber for the first time. The atomized fuel comes into full contact with the remaining high-temperature and high-pressure gas in the combustion chamber to form a mixture, which prepares for the first combustion power stroke. like Figure 3e As shown, the air-fuel mixture is compressed and ignited, causing the pressure and temperature in the combustion chamber to rise sharply. This pushes piston 3 from top dead center to bottom dead center, converting the chemical energy of the fuel into the mechanical energy of the piston movement, thus completing the first combustion and work.

[0033] Fourth stroke: Exhaust and replenishment stroke like Figure 3fAs shown, after combustion, the exhaust valve 10 is opened and the intake valve is closed. The piston 3 moves upward, and the exhaust gas generated during the first combustion power stroke is discharged from the combustion chamber through the exhaust valve 10 and the exhaust passage 5. When the piston 3 approaches the top dead center, the exhaust valve 10 is closed to prevent premature leakage of high-temperature and high-pressure gas.

[0034] like Figure 3g As shown, when the piston is near top dead center, the gas injector 9 performs an injection operation, injecting the high-temperature and high-pressure gas stored in the gas tank 12 and the first gas passage into the combustion chamber through the second gas passage 14 and the gas injector 9, thereby replenishing the combustion chamber with fresh air.

[0035] Fifth stroke: The second compression and combustion power stroke like Figure 3h As shown, when all the gas in the gas tank 12 is emptied, before the piston 3 reaches the top dead center, the exhaust valve 10 is closed, and the gas injector 9 and the fuel injector 8 are opened simultaneously to perform the second fuel injection operation, injecting atomized fuel into the combustion chamber; the gas injected by the gas injector 9 increases the gas disturbance in the combustion chamber, thereby improving the degree of fuel-air mixing in the combustion chamber and improving combustion efficiency.

[0036] like Figure 3i As shown, the air-fuel mixture in the combustion chamber is ignited for the second time. The high-temperature and high-pressure gas generated by the combustion pushes piston 3 from top dead center to bottom dead center, outputting power and completing the second combustion cycle.

[0037] Sixth stroke: Second exhaust stroke like Figure 3j As shown, after combustion, the exhaust valve 10 is opened, the piston 3 moves upward and enters the exhaust stage, and the exhaust gas produced after the second combustion is completely discharged through the exhaust passage.

[0038] When piston 3 reaches top dead center, a complete six-stroke working cycle ends, and then the next cycle begins, repeating the working process of the above stages.

[0039] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style of the specification is merely for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in the embodiments can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A two-stage combustion six-stroke engine comprising a single cylinder engine body, an oil injector (8), characterized in that, The single-cylinder engine body includes a cylinder head (1), a cylinder block (2), a piston (3), an intake manifold (4), an intake valve (6), an exhaust manifold (5), and an exhaust valve (10). The piston (3) reciprocates within the cylinder body formed by the cylinder head (1) and the cylinder block (2). The space enclosed by the three components constitutes a combustion chamber. The six-stroke engine also includes a valve train unit. The valve train unit is integrated on the cylinder head. The gas distribution unit includes a gas storage tank (12), a first gas passage (13), a second gas passage (14), and a gas injector (9), forming a gas storage and injection circuit to realize compressed gas storage and gas release; The first air passage (13) is connected to the combustion chamber at one end and to the air storage tank (12) at the other end, and an air storage valve (7) is provided at the end connected to the combustion chamber. One end of the second air passage (14) is connected to the gas storage tank (12), and the other end is connected to the combustion chamber through the gas injector (9). The injection port of the gas injector (9) extends into the combustion chamber. Wherein, the center of the nozzle of the injector (8) is located on the first axis (L1); the first axis (L1) is perpendicular to the cylinder head and intersects the cylinder head at the center; the center of the nozzle of the gas reservoir (7) and the gas injector (9) is located away from the first axis (L1) to form tumble in the combustion chamber; The six-stroke engine utilizes the gas storage tank (12) and part of the first air passage (13) to achieve two consecutive compressions and combustions of the working fluid in the same cylinder. In one working cycle, it completes one intake stroke, the first compression and gas storage stroke, the first combustion power stroke, the exhaust and gas replenishment stroke, the second compression and combustion power stroke, and the second exhaust stroke. Moreover, during the second compression and combustion power stroke, the gas injected into the combustion chamber by the gas injector (9) interacts with the in-cylinder airflow formed near the gas storage valve (7), forming an enhanced tumble motion in the combustion chamber.

2. The two-stage combustion six-stroke engine of claim 1, wherein, The cylinder head (1) is provided with the intake valve (6), the exhaust valve (10) and the fuel injector (8), the fuel injector (8) is located between the intake valve (6) and the exhaust valve (10) and is arranged at the center of the cylinder head.

3. The two-stage combustion six-stroke engine of claim 1, wherein, The axis of the injector (8) forms an angle of 15-25° with the axis of the cylinder head (1).

4. The two-stage combustion six-stroke engine of claim 1, wherein, The axis of the gas injector (9) forms an angle of 15-25° with the axis of the cylinder head (1).

5. The two-stage combustion six-stroke engine according to claim 1, characterized in that, The diameter ratio of the storage valve (7) to the intake valve (6) is 1:

6.

6. The two-stage combustion six-stroke engine according to claim 1, characterized in that, A one-way valve (11) is provided in the first air passage (13), which allows gas to flow from the combustion chamber to the gas storage tank (12); and the one-way valve (11) is located close to the cylinder head, so that the area in the first air passage from the one-way valve (11) to the gas storage tank (12) contains the gas from the combustion chamber.

7. The two-stage combustion six-stroke engine according to claim 1, characterized in that, The working process of the two-stage combustion six-stroke engine includes the following strokes performed sequentially: Intake stroke: The piston moves downward from top dead center, opening the intake valve (6) and closing the exhaust valve (10), allowing fresh air to enter the combustion chamber; First compression and storage stroke: The piston moves upward from the bottom dead center, compressing the gas in the combustion chamber, and the intake valve (6) and exhaust valve are closed; and when the piston moves up to 3 / 4 of the distance from the top of the cylinder head, the storage valve (7) is opened, and part of the gas in the combustion chamber is stored in the storage tank (12) and part of the first air passage (13); First combustion power stroke: The gas storage valve (7) is closed, the fuel injector (8) injects fuel into the combustion chamber for the first time, the air-fuel mixture is compressed and ignited, pushing the piston (3) to move downward to output power, and the first combustion power stroke is completed; Exhaust and replenishment stroke: Open the exhaust valve (10), close the intake valve, and discharge the exhaust gas from the first combustion through the exhaust passage; when the piston (3) approaches the top dead center, close the exhaust valve (10), and the gas injector (9) injects the gas from the gas tank (12) and the first gas passage into the combustion chamber to replenish the working fluid; Second compression and combustion power stroke: When all the gas in the gas tank (12) is emptied, before the piston (3) reaches the top dead center, the exhaust valve (10) is closed, and the gas injector (9) and the fuel injector (8) are opened at the same time to perform the second fuel injection operation; the mixture is compressed and ignited, pushing the piston to move downward to output power and complete the second combustion power stroke. Second exhaust stroke: After combustion, the exhaust valve is opened, the piston (3) moves upward, and the exhaust gas produced by the second combustion is discharged to complete the cycle.

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