Opposed piston two-stroke engine, combustion system and engine control method

Abstract

The present invention discloses an opposed-piston two-stroke engine, a combustion system and an engine control method, wherein the two-stroke engine comprises: a cylinder liner, a throat section protruding toward the center is formed in the middle, one side of the cylinder liner located at the throat section is an intake section, and the other side is an exhaust section, the inner diameter of the throat section is smaller than the intake section and the exhaust section, respectively, an intake hole is arranged on the outside of the intake section, and an exhaust hole is arranged on the outside of the exhaust section; a gas injection device is connected to the outside of the cylinder liner, and the gas injection device has an injection port inserted into the throat section; a pre-combustion sleeve is connected to the outside of the cylinder liner, one end of the pre-combustion sleeve extends into the throat section, and a spark plug is arranged in the pre-combustion sleeve; an intake piston is located in the intake section; and an exhaust piston is located in the exhaust section. The present invention enhances the internal ventilation effect, reduces the short-circuit situation that the airflow enters the cylinder liner from the intake hole and is directly discharged from the exhaust hole, and greatly improves the working efficiency of the two-stroke engine.

Description

Technical Field

[0001] The present invention relates to a combustion engine, and in particular to an opposed-piston two-stroke engine, a combustion system and an engine control method. Background Art

[0002] The opposed piston two-stroke engine has the advantages of high power density, small number of parts and low cost, multi-fuel adaptability, high power density, low cost, and positive contribution to hybrid extended-range vehicles and carbon neutrality. However, it also has its own disadvantages. Due to the scavenging characteristics of the opposed piston two-stroke engine itself, more than 40% of the fresh air will directly enter the exhaust duct due to the scavenging process, causing great waste, and it is difficult to fully ventilate the interior, affecting thermal efficiency. Therefore, there is an urgent need for an opposed piston two-stroke engine that can better enhance the internal ventilation effect. Summary of the invention

[0003] The purpose of the present invention is to provide an opposed-piston two-stroke engine, a combustion system and an engine control method to solve one or more technical problems existing in the prior art and at least provide a beneficial choice or create conditions.

[0004] The solution of the present invention to solve its technical problem is:

[0005] An opposed-piston two-stroke engine comprises: a cylinder liner, a throat section protruding toward the center is formed in the middle, one side of the cylinder liner located at the throat section is an intake section, and the other side is an exhaust section, the inner diameter of the throat section is smaller than the intake section and the exhaust section, respectively, an intake hole is provided on the outer side of the intake section, and an exhaust hole is provided on the outer side of the exhaust section; a gas injection device connected to the outer side of the cylinder liner, the gas injection device has an injection port inserted into the throat section; a pre-combustion sleeve, connected to the outer side of the cylinder liner, one end of the pre-combustion sleeve extends into the throat section, and a spark plug is provided in the pre-combustion sleeve; an intake piston, located in the intake section; an exhaust piston, located in the exhaust section.

[0006] This technical solution has at least the following beneficial effects: the inner side of the cylinder liner bulges toward its center at the middle position, so that the inner side of the cylinder liner forms a throat section with a smaller inner diameter at the middle position, while the inner diameters of the intake section and the exhaust section on both sides of the throat section are relatively large. At this time, a Venturi tube structure is formed in the cylinder liner, and the area between the intake section and the throat section forms a contraction area, and the area between the throat section and the exhaust section forms a diffusion area. When working, combustible gas is sprayed into the cylinder liner from the gas injection device, and the intake piston and the exhaust piston move in the intake section and the exhaust section respectively. By the mutual approach of the two, the air in the cylinder liner is compressed, and the spark plug ignites the compressed mixed gas. At this time, the intake piston The exhaust piston moves away from the exhaust hole and does work outward. When the exhaust piston passes through the exhaust hole, the exhaust gas can be discharged outward from the exhaust hole. When the intake piston passes through the intake hole, the airflow can enter the intake section from the intake hole. When the airflow reaches the throat section, the airflow speed is accelerated, so that a low-pressure area is formed inside the pre-combustion sleeve, which can suck the exhaust gas in the pre-combustion sleeve. When the airflow reaches the exhaust section, since the internal space of the exhaust section is larger than the internal space of the throat section, the airflow diffuses inside the exhaust section, which can effectively improve the effect of the airflow to carry away the exhaust gas in the exhaust section. In this way, the internal ventilation effect is enhanced, the working medium is increased, and the short-circuit situation of the airflow entering the cylinder liner from the intake hole and then being discharged directly from the exhaust hole is reduced, which greatly improves the working efficiency of the two-stroke engine.

[0007] As a further improvement of the above technical solution, the length direction of the air inlet does not intersect with the axis of the cylinder liner, and a plurality of the air inlet holes are arranged around the cylinder liner. When the airflow enters from the air inlet hole, since the length direction of the air inlet hole does not intersect with the axis of the cylinder liner, that is, the air inlet hole is eccentrically arranged, multiple airflows form vortex air masses in the air inlet section, which promotes the exhaust gas to be discharged and reduces the mixing of the exhaust gas. At the same time, the vortex air mass is throttled when passing through the throat section, which effectively prevents the short circuit of the air from the air inlet to the exhaust hole, improves the fresh air capture rate in the cylinder liner, and further improves the ventilation efficiency.

[0008] As a further improvement of the above technical solution, the distance between the air inlet and the throat section is greater than the distance between the air outlet and the throat section, and the axial length of the air inlet along the cylinder liner is less than the axial length of the air outlet along the cylinder liner. Since the distance between the air inlet and the throat section is greater than the distance between the air outlet and the throat section, when the air inlet piston and the air outlet piston move away from each other at the throat section, the air outlet piston will first pass through the air outlet, and at this time, the pressure inside the cylinder liner is first relieved, and the exhaust time is increased, thereby ensuring that the cylinder liner can be pressurized next time, and the axial length of the air outlet along the cylinder liner is greater than the axial length of the air inlet along the cylinder liner, further improving the exhaust efficiency.

[0009] As a further improvement of the above technical solution, when the intake piston and the exhaust piston approach each other, the exhaust piston reaches the throat section earlier than the intake piston. By adjusting the activity rhythm of the exhaust piston to be faster than the activity rhythm of the intake piston, the exhaust hole can be opened earlier and not closed late, so that the mixed airflow in the cylinder is not easy to leak directly from the exhaust hole.

[0010] As a further improvement of the above technical solution, a first protrusion and a first recess are formed on the end surface of the intake piston near the throat section, and the first recess is closer to the spark plug than the first protrusion, and a second protrusion and a second recess are formed on the end surface of the exhaust piston near the throat section, and the second recess is closer to the spark plug than the second protrusion. A first protrusion and a first recess are formed on the end face of the intake piston, so that the cross-sectional shape of the intake piston in the direction from the first protrusion to the first recess is S-shaped. Similarly, the cross-sectional shape of the exhaust piston in the direction from the second protrusion to the second recess is S-shaped. When the exhaust piston and the intake piston approach each other, the airflow forms a tumble flow and a strong squeeze flow along the axis of the cylinder liner, driving the gas in the cylinder liner to mix. When the exhaust piston and the intake piston approach each other to the end of the stroke, a radial small-diameter virtual cylinder head main combustion chamber with a larger space at the throat section located at the first recess and the second recess and a smaller space at other positions is formed, forming a tent-shaped combustion chamber with the effect of a traditional gasoline engine, further solving the problem of poor mixing effect when the gas injection device is side-mounted in a two-stroke engine, and improving work efficiency.

[0011] As a further improvement of the above technical solution, the apex of the first protrusion and the apex of the second protrusion are staggered. When the intake piston and the exhaust piston are close to each other, since the machine point of the first protrusion and the apex of the second protrusion are staggered, a gap for airflow to pass through is formed between the first protrusion and the second protrusion, which can guide the airflow so that the airflow circulates at the throat section.

[0012] As a further improvement of the above technical solution, the injection port is directly opposite to the end of the pre-combustion sleeve, and the gas injection device can inject gas into the pre-combustion sleeve. When the gas injection device injects combustible gas into the cylinder sleeve, since its injection port is directly opposite to the end of the pre-combustion sleeve, the combustible gas can be directly filled into the pre-combustion sleeve, so that a rich mixed gas is formed in the pre-combustion chamber, a relatively rich mixed gas is formed near the pre-combustion chamber, and a relatively lean mixed gas is formed at the rest of the throat section, so that the concentration of the mixed gas is distributed in a stepwise manner. At the ignition moment, the spark plug ignites, ignites the rich mixed gas in the pre-combustion sleeve, forms a high-energy ignition jet, and quickly ignites the relatively lean mixed gas, achieving ultra-lean combustion and improving the efficiency of the two-stroke engine.

[0013] As a further improvement of the above technical solution, the cylinder liner is provided with an axially extending cooling channel, and the outer side of the cylinder liner is provided with a water inlet and a water outlet respectively connected to the two ends of the cooling channel. During operation, external cold water can enter the cooling channel from the water inlet and then flow out from the water outlet, which can reduce the exhaust port temperature, improve reliability, help suppress the occurrence of knock, achieve controllable high-efficiency compression ignition and ignition, and improve the efficiency of the whole machine.

[0014] A combustion system comprises: a turbocharger; a compressor connected to the turbocharger via a pipeline; in the above-mentioned two-stroke engine, the compressor is connected to the air inlet via a pipeline, and the exhaust hole is connected to an exhaust pipe.

[0015] This technical solution has at least the following beneficial effects: when working, the outside atmosphere enters the air intake hole of the two-stroke engine through the turbocharger and the compressor, so as to replenish air into the cylinder liner, while the exhaust gas flows outward from the exhaust hole on the cylinder liner to the exhaust pipe. Since the two-stroke engine enhances the internal ventilation effect and reduces the short circuit of the airflow entering the cylinder liner from the air intake hole and then being discharged directly from the exhaust hole, the combustion efficiency of the combustion system formed is greatly improved.

[0016] An engine control method, using the above two-stroke engine, comprises:

[0017] Get the intake pressure and exhaust pressure;

[0018] When low power output is required, the intake and exhaust pressures are controlled to be equal to the exhaust pressure, the intake flow is reduced, the residual exhaust gas coefficient in the cylinder sleeve is controlled to be around 50%, the compression end temperature is increased, and compression ignition is achieved;

[0019] When medium power output is required, the intake pressure and exhaust pressure are controlled to form a small pressure difference, and the residual exhaust gas coefficient in the cylinder liner is controlled between 20-50%, so as to achieve compression ignition with controllable pressure rise rate;

[0020] When high power output is required, the intake pressure and exhaust pressure are controlled to form a large pressure difference, the residual exhaust gas coefficient in the cylinder liner is controlled below 5%, and the passive pre-combustion sleeve spark plug is used to ignite the main combustion chamber, achieving efficient ignition and combustion with controllable explosion pressure and pressure rise rate under high load.

[0021] This technical solution has at least the following beneficial effects: when the two-stroke engine is used for operation, the internal ventilation effect is enhanced, and the short circuit situation in which the airflow enters the cylinder liner from the intake hole and is directly discharged from the exhaust hole is reduced, thereby greatly improving the working efficiency of the two-stroke engine. In addition, by controlling the pressure difference between the intake pressure and the exhaust pressure, the combustion system is controlled to realize a complementary and efficient combustion mode of compression ignition and high-energy ignition coupling, thereby further improving the working efficiency of the two-stroke engine. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly describes the drawings required for use in the description of the embodiments. Obviously, the drawings described are only part of the embodiments of the present invention, not all of the embodiments, and those skilled in the art can also obtain other design solutions and drawings based on these drawings without creative work.

[0023] Figure 1 It is a top view of a two-stroke engine of the present invention.

[0024] Figure 2 yes Figure 1 Schematic diagram of the AA cross-section structure.

[0025] Figure 3 It is a schematic diagram of the combustion system structure of the present invention.

[0026] In the accompanying drawings: 100-cylinder liner, 110-throat section, 120-intake section, 121-intake hole, 130-exhaust section, 131-exhaust hole, 140-water inlet hole, 150-water outlet hole, 200-gas injection device, 310-pre-combustion sleeve, 320-spark plug, 400-intake piston, 410-first protrusion, 420-first recess, 500-exhaust piston, 510-second protrusion, 520-second recess, 610-turbocharger, 620-compressor, 630-exhaust pipe. DETAILED DESCRIPTION

[0027] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0028] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., and orientations or positional relationships indicated are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0029] In the description of the present invention, "several" means one or more, "more" means more than two, "greater than", "less than", "exceed" etc. are understood as not including the number itself, and "above", "below", "within" etc. are understood as including the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0030] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0031] Reference Figure 1 and Figure 2 , an opposed piston two-stroke engine, comprising a cylinder liner 100, a gas injection device 200, a pre-combustion sleeve 310, an intake piston 400 and an exhaust piston 500, wherein a throat section 110 protruding toward the center is formed in the middle of the cylinder liner 100, one side of the throat section 110 of the cylinder liner 100 is an intake section 120, and the other side is an exhaust section 130, the inner diameter of the throat section 110 is smaller than the intake section 120 and the exhaust section 130, respectively, an intake hole 121 is arranged on the outside of the intake section 120, and an exhaust hole 131 is arranged on the outside of the exhaust section 130, and of course, the connection position between the throat section 110 and the intake section 120, and the connection position between the throat section 110 and the exhaust The connection position between the sections 130 is designed with a smooth transition to ensure that the airflow flows smoothly in the cylinder liner 100. The flow area of ​​the throat section 110 can be 0.6 to 0.8 of the flow area of ​​the intake section 120 or the exhaust section 130. The gas injection device 200 is connected to the outside of the cylinder liner 100, and the gas injection device 200 has an injection port inserted into the throat section 110. The pre-combustion sleeve 310 is connected to the outside of the cylinder liner 100, and one end of the pre-combustion sleeve 310 extends into the throat section 110. A spark plug 320 is arranged in the pre-combustion sleeve 310. The intake piston 400 is located in the intake section 120; the exhaust piston 500 is located in the exhaust section 130.

[0032] As can be seen from the above, the inner side of the cylinder sleeve 100 bulges toward the center at the middle position, so that the inner side of the cylinder sleeve 100 forms a throat section 110 with a smaller inner diameter at the middle position, while the inner diameters of the intake section 120 and the exhaust section 130 on both sides of the throat section 110 are relatively large. At this time, a Venturi tube structure is formed in the cylinder sleeve 100, and the area between the intake section 120 and the throat section 110 forms a contraction area, and the area between the throat section 110 and the exhaust section forms a diffusion area. When working, combustible gas is injected into the cylinder sleeve 100 from the gas injection device 200, and the intake piston 400 and the exhaust piston 500 move in the intake section 120 and the exhaust section 130 respectively. By the mutual approach of the two, the air in the cylinder sleeve 100 is compressed, and the spark plug 320 ignites the compressed mixed gas. At this time, the intake piston 400 and the exhaust piston 5 00 move away from each other and do work outwards. When the exhaust piston 500 passes through the exhaust hole 131, the exhaust gas can be discharged outwards from the exhaust hole 131. When the intake piston 400 passes through the intake hole 121, the airflow can enter the intake section 120 from the intake hole 121. When the airflow reaches the throat section 110, the airflow speed is accelerated, so that a low-pressure area is formed inside the pre-combustion sleeve 310, and the exhaust gas in the pre-combustion sleeve 310 can be sucked. When the airflow reaches the exhaust section 130, since the internal space of the exhaust section 130 is larger than the internal space of the throat section 110, the airflow diffuses inside the exhaust section 130, which can effectively improve the effect of the airflow taking away the exhaust gas in the exhaust section 130. In this way, the internal ventilation effect is enhanced, the working medium is increased, and the short-circuit situation that the airflow enters the cylinder liner 100 from the intake hole 121 and is directly discharged from the exhaust hole 131 is reduced, thereby greatly improving the working efficiency of the two-stroke engine.

[0033] When the air inlet 121 is opened, its extension direction can be directly toward the central axis of the cylinder sleeve 100, but at this time, the converged gas is easy to directly pass along the middle of the cylinder sleeve 100 and then flow out from the exhaust hole 131. Therefore, in order to improve the effect of air replenishment into the cylinder sleeve 100, in this embodiment, the length direction of the air inlet 121 does not intersect with the axis of the cylinder sleeve 100, and the air inlet 121 is arranged around the cylinder sleeve 100. When the air flow enters from the air inlet 121, since the length direction of the air inlet 121 does not intersect with the axis of the cylinder sleeve 100, that is, the air inlet 121 is eccentrically arranged, at this time, multiple air flows form vortex air masses in the air inlet section 120, which promotes the exhaust gas to be discharged and reduces the mixing of the exhaust gas. At the same time, the vortex air mass is throttled when passing through the throat section 110, which effectively prevents the short circuit of air from the air inlet to the exhaust hole 131, improves the fresh air capture rate in the cylinder sleeve 100, and further improves the ventilation efficiency. In practical applications, the swirl ratio ranges from 2.5 to 3.5.

[0034] When the intake piston 400 and the exhaust piston 500 move away from each other, if the distance between the intake hole 121 and the throat section 110 is equal to the distance between the exhaust hole 131 and the throat section 110, the cylinder liner 100 can be simultaneously charged and exhausted. However, since the cylinder liner 100 is in a high-pressure state during the working process, it is difficult to directly charge the cylinder liner 100. Therefore, it can be designed to exhaust the cylinder liner 100 first. Specifically, the distance between the intake hole 121 and the throat section 110 is greater than the distance between the exhaust hole 131 and the throat section 110, and the axial length of the intake hole 121 along the cylinder liner 100 is less than the axial length of the exhaust hole 131 along the cylinder liner 100. Since the distance between the intake hole 121 and the throat section 110 is greater than the distance between the exhaust hole 131 and the throat section 110, when the intake piston 400 and the exhaust piston 500 move away from each other at the throat section 110, the exhaust piston 500 will first pass through the exhaust hole 131. At this time, the pressure inside the cylinder liner 100 is first relieved to increase the exhaust time, thereby ensuring that the cylinder liner 100 can be pressurized next time, and the axial length of the exhaust hole 131 along the cylinder liner 100 is greater than the axial length of the intake hole 121 along the cylinder liner 100, further improving the exhaust efficiency.

[0035] Furthermore, when the intake piston 400 and the exhaust piston 500 are close to each other, the exhaust piston 500 reaches the throat section 110 earlier than the intake piston 400. By adjusting the activity rhythm of the exhaust piston 500 to be faster than the activity rhythm of the intake piston 400, the exhaust hole 131 can be opened earlier and not closed late, so that the mixed air flow in the cylinder is not easy to leak directly from the exhaust hole 131. In actual application, the exhaust piston 500 and the intake piston 400 are respectively driven by the crank to move in the exhaust section 130 and the intake section 120 respectively. The exhaust piston 500 can be designed to be 5 to 15 degrees earlier than the intake piston 400, so that the exhaust piston 500 reaches the throat section 110 earlier than the intake piston 400.

[0036] The ends of the intake piston 400 and the exhaust piston 500 are formed with tapered portions to adapt to the smooth transition position between the throat section 110 and the intake section 120 and the exhaust section 130. In order to further improve the compression effect of the mixed gas during the compression of the mixed gas, in the present embodiment, the end surface of the intake piston 400 close to the throat section 110 is formed with a first protrusion 410 and a first recessed portion 420, and the first recessed portion 420 is closer to the spark plug 320 than the first protrusion 410. The end surface of the exhaust piston 500 close to the throat section 110 is formed with a second protrusion 510 and a second recessed portion 520, and the second recessed portion 520 is closer to the spark plug 320 than the second protrusion 510. A first protrusion 410 and a first recess 420 are formed on the end surface of the intake piston 400, so that the cross-sectional shape of the intake piston 400 in the direction from the first protrusion 410 to the first recess 420 is S-shaped. Similarly, the cross-sectional shape of the exhaust piston 500 in the direction from the second protrusion 510 to the second recess 520 is S-shaped. When the exhaust piston 500 and the intake piston 400 approach each other, the airflow forms a tumble flow and a strong squeeze flow along the axis of the cylinder liner 100, driving the gas in the cylinder liner 100 to mix. When the exhaust piston 500 and the intake piston 400 approach each other to the end of the stroke, a radial small-diameter virtual cylinder head main combustion chamber with a larger space is formed at the throat section 110 located at the first recess 420 and the second recess 520 and a smaller space at other positions, forming a tent-shaped combustion chamber with the effect of a traditional gasoline engine, further solving the problem of poor mixing effect when the gas injection device 200 is side-mounted in the two-stroke engine, and improving work efficiency.

[0037] Furthermore, the apex of the first protrusion 410 is staggered with the apex of the second protrusion 510. When the intake piston 400 and the exhaust piston 500 are close to each other, since the machine point of the first protrusion 410 and the apex of the second protrusion 510 are staggered, a gap for airflow to pass through is formed between the first protrusion 410 and the second protrusion 510, which can guide the airflow so that the airflow circulates at the throat section 110.

[0038] The gas injection device 200 includes an injector sleeve connected to the outside of the cylinder sleeve 100 and an injector installed in the injector sleeve. An injection port is formed at the end position of the injector sleeve connected to the outside of the cylinder sleeve 100. The injector injects combustible gas into the cylinder sleeve 100 from the injection port. The injector sleeve can be installed at any position outside the pre-combustion sleeve 310. In order to improve the inflation effect into the pre-combustion sleeve 310, in this embodiment, the injection port is directly opposite to the end of the pre-combustion sleeve 310, and the gas injection device 200 can inject gas into the pre-combustion sleeve 310. When the gas injection device 200 injects combustible gas into the cylinder liner 100, since its injection port is directly opposite to the end of the pre-combustion sleeve 310, the combustible gas can be directly filled into the pre-combustion sleeve 310, so that a rich mixture is formed in the pre-combustion chamber, a relatively rich mixture is formed near the pre-combustion chamber, and a relatively lean mixture is formed at the rest of the throat section 110. In this way, the concentration of the mixture is distributed in a stepwise manner. At the moment of ignition, the spark plug 320 ignites and ignites the rich mixture in the pre-combustion sleeve 310, forming a high-energy ignition jet, which quickly ignites the relatively lean mixture, achieves ultra-lean combustion, and improves the efficiency of the two-stroke engine.

[0039] In order to cool the whole, in this embodiment, the cylinder liner 100 is provided with a cooling channel extending in the axial direction. The cylinder liner 100 itself has a certain wall thickness, and a hole can be directly opened in the axial direction on the cooling channel to form the cooling channel. The outer side of the cylinder liner 100 is provided with a water inlet hole 140 and a water outlet hole 150 respectively connected to the two ends of the cooling channel. During operation, external cold water can enter the cooling channel from the water inlet hole 140, and then flow out from the water outlet hole 150, which can reduce the temperature of the exhaust hole 131, improve reliability, and help to suppress the occurrence of knock, realize controllable high-efficiency compression ignition and ignition, and improve the efficiency of the whole machine. In practical applications, a plurality of cooling channels can be arranged at intervals around the cylinder liner 100, and cooling channels are respectively arranged at the positions of the intake section 120 and the exhaust section 130, and a cooling groove is arranged around the position of the outer side of the cylinder liner 100 facing the throat section 110, so as to realize cooling at this position.

[0040] A combustion system such as Figure 3 As shown, it includes: a turbocharger 610; a compressor 620, which is connected to the turbocharger 610 through a pipeline; in the above-mentioned two-stroke engine, the compressor 620 is connected to the air inlet 121 through a pipeline, and the exhaust hole 131 is connected to an exhaust pipe 630.

[0041] In this combustion system, when working, the outside atmosphere enters the air inlet 121 of the two-stroke engine through the turbocharger 610 and the compressor 620 to replenish air into the cylinder liner 100, while the exhaust gas flows out from the exhaust hole 131 on the cylinder liner 100 to the exhaust pipe 630. Since the two-stroke engine enhances the internal ventilation effect and reduces the short circuit of the airflow entering the cylinder liner 100 from the air inlet 121 and then being discharged directly from the exhaust hole 131, the combustion efficiency of the formed combustion system is greatly improved. In actual applications, part of the exhaust gas discharged from the exhaust hole 131 will flow back to the turbocharger 610 to improve the heat utilization rate.

[0042] An engine control method, using the above two-stroke engine, includes but is not limited to the following steps:

[0043] Step S100, obtaining intake pressure and exhaust pressure;

[0044] Step S200, adjusting the intake pressure and the exhaust pressure according to the required output power, and when the output power decreases, controlling to reduce the pressure difference between the intake pressure and the exhaust pressure.

[0045] In this engine control method, when this two-stroke engine is used to work, the internal ventilation effect is enhanced, and the short circuit of the airflow entering the cylinder liner 100 from the intake hole 121 and being directly discharged from the exhaust hole 131 is reduced, which greatly improves the working efficiency of the two-stroke engine. In addition, by controlling the pressure difference between the intake pressure and the exhaust pressure, the combustion system is controlled to achieve a complementary and efficient combustion mode of compression ignition and high-energy ignition coupling, thereby further improving the working efficiency of the two-stroke engine.

[0046] In step S200, when a low power output is required, the intake and exhaust pressure difference is controlled to be zero, the intake flow rate is reduced, the residual exhaust gas coefficient in the cylinder sleeve 100 is controlled to be about 50%, the compression end temperature is increased, and compression ignition is achieved;

[0047] When medium power output is required, the intake and exhaust pressure difference is controlled to be small, and the residual exhaust gas coefficient in the cylinder sleeve 100 is controlled to be between 20-50%, so as to realize compression ignition with controllable pressure rise rate;

[0048] When high power output is required, a large intake and exhaust pressure difference is controlled, and the residual exhaust gas coefficient in the cylinder sleeve 100 is controlled below 5%. The passive pre-combustion sleeve 310 and the spark plug 320 are used to ignite the main combustion chamber, so as to achieve efficient ignition and combustion with controllable explosion pressure and pressure rise rate under high load.

[0049] The preferred embodiments of the present invention are described in detail above, but the invention is not limited to the embodiments. Those skilled in the art may make various equivalent modifications or substitutions without violating the spirit of the invention. These equivalent modifications or substitutions are all included in the scope defined by the claims of this application.

Claims

1. An opposed piston two-stroke engine, characterized in that: include: A cylinder sleeve (100) is provided with a throat section (110) protruding toward the center at the middle part; one side of the cylinder sleeve (100) located at the throat section (110) is an intake section (120), and the other side is an exhaust section (130); the inner diameter of the throat section (110) is smaller than that of the intake section (120) and the exhaust section (130), respectively; an intake hole (121) is provided on the outside of the intake section (120), and an exhaust hole (131) is provided on the outside of the exhaust section (130); A gas injection device (200) connected to the outside of the cylinder liner (100), the gas injection device (200) having an injection port inserted into the throat section (110); A pre-combustion sleeve (310) is connected to the outside of the cylinder sleeve (100), one end of the pre-combustion sleeve (310) extends into the throat section (110), and a spark plug (320) is arranged in the pre-combustion sleeve (310); An air intake piston (400) is located in the air intake section (120); An exhaust piston (500) is located in the exhaust section (130); a first protrusion (410) and a first recess (420) are formed on the end surface of the intake piston (400) close to the throat section (110); the first recess (420) is closer to the spark plug (320) than the first protrusion (410); a second protrusion (510) and a second recess (520) are formed on the end surface of the exhaust piston (500) close to the throat section (110); the second recess (520) is closer to the spark plug (320) than the second protrusion (510); and the apex of the first protrusion (410) and the apex of the second protrusion (510) are staggered.

2. The opposed-piston two-stroke engine according to claim 1, characterized in that: The length direction of the air intake hole (121) does not intersect with the axis of the cylinder liner (100), and a plurality of the air intake holes (121) are arranged around the cylinder liner (100).

3. The opposed-piston two-stroke engine according to claim 1, characterized in that: The distance between the air inlet hole (121) and the throat section (110) is greater than the distance between the air outlet hole (131) and the throat section (110), and the axial length of the air inlet hole (121) along the cylinder liner (100) is less than the axial length of the air outlet hole (131) along the cylinder liner (100).

4. The opposed-piston two-stroke engine according to claim 3, characterized in that: When the intake piston (400) and the exhaust piston (500) approach each other, the exhaust piston (500) reaches the throat section (110) earlier than the intake piston (400).

5. The opposed-piston two-stroke engine according to claim 1, characterized in that: The injection port is directly opposite to the end of the pre-combustion sleeve (310), and the gas injection device (200) can inject gas into the pre-combustion sleeve (310).

6. The opposed-piston two-stroke engine according to claim 1, characterized in that: The cylinder sleeve (100) is provided with a cooling channel extending axially therein, and the cylinder sleeve (100) is provided with a water inlet hole (140) and a water outlet hole (150) respectively connected to two ends of the cooling channel on the outside.

7. A combustion system, characterized in that: include: Turbocharger (610); A compressor (620) connected to the turbocharger (610) via a pipeline; The two-stroke engine according to any one of claims 1 to 6, wherein the compressor (620) is connected to the air inlet (121) via a pipeline, and the exhaust hole (131) is connected to an exhaust pipe (630).

8. An engine control method, using the two-stroke engine according to any one of claims 1 to 6, characterized in that: include: Get the intake pressure and exhaust pressure; When a small power output is required, the intake pressure is controlled to be equal to the exhaust pressure, the intake flow rate is reduced, the residual exhaust gas coefficient in the cylinder sleeve (100) is controlled to be about 50%, the compression end temperature is increased, and compression ignition is achieved; When medium power output is required, the intake pressure and the exhaust pressure are controlled to form a small pressure difference, and the residual exhaust gas coefficient in the cylinder sleeve (100) is controlled to be between 20-50%, so as to achieve compression ignition with a controllable pressure rise rate; When high power output is required, the intake pressure and the exhaust pressure are controlled to form a large pressure difference, the residual exhaust gas coefficient in the cylinder sleeve (100) is controlled to be below 5%, and the passive pre-combustion sleeve (310) spark plug (320) is used to ignite the main combustion chamber, so as to achieve high-efficiency ignition and combustion with controllable explosion pressure and pressure rise rate under high load.

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