Two-stroke two-way fuel injection system and engine

Abstract

The invention discloses a two-stroke two-way fuel injection system, and belongs to the technical field of engines. Comprising a manifold oil nozzle, an air auxiliary injection unit, a pressure regulating valve and an air pump. The air pump communicates with the air auxiliary injection unit and the pressure regulating valve, and an oil outlet of the pressure regulating valve communicates with the manifold oil nozzle and the air auxiliary injection unit and is used for supplying oil to the manifold oil nozzle and the air auxiliary injection unit. The invention further discloses an engine which comprises an engine body, an oil supply unit and the system, and the air pump is installed on the engine body; an oil inlet of the pressure regulating valve is communicated with the oil supply unit; the air-assisted injection unit is located at a cylinder head of the engine body; lubricating of a piston and a connecting rod moving part is guaranteed by adjusting the ratio of manifold oil injection to air-assisted oil injection, meanwhile, the cleanliness of compressed air is guaranteed by adopting an oil-gas mixing cavity with a filter screen, and then the reliability of air-assisted injection is improved.

Description

Technical Field

[0001] The present invention relates to a fuel injection system and an engine, in particular to a two-stroke dual-path fuel injection engine, belonging to the technical field of engines. Background Art

[0002] Due to the high viscosity and poor atomization of heavy oil, direct injection (DI) is the ideal fueling method for heavy oil piston engines. This reduces fuel wall wetting, improves atomization, and reduces fuel consumption. Traditional DI (injecting fuel directly into the cylinder at high pressure) suffers from high injection pressures and long spray penetration distances, which can lead to fuel wall wetting and cylinder flooding, hindering combustion. Therefore, it cannot meet the requirements for good atomization and mixing of heavy oil fuels.

[0003] Compared to traditional high-pressure direct injection, low-pressure injection is a better choice for heavy oil fuels. Low-pressure direct injection generally uses air-assisted injection. This air-assisted injection sprays the fuel into relatively high-pressure air, mixing it through friction with the high-pressure air to achieve initial atomization. The fuel is then sprayed into the combustion chamber along with the high-pressure air for secondary atomization. The expansion of the compressed air accelerates the breakup of the fuel droplets, achieving good atomization at relatively low injection pressures. However, the air nozzle used in this technology places high demands on the cleanliness of the compressed air, and this technology alone cannot effectively lubricate moving parts such as the piston and connecting rod of a two-stroke engine, resulting in poor reliability.

[0004] In view of the above situation, in order to overcome the above technical problems, the present invention designs a two-stroke dual-way fuel injection engine to solve the above technical problems. Summary of the Invention

[0005] The technical objectives of this invention are to address the poor reliability of single-line air-assisted injection systems. The main purpose of this invention is to provide a two-stroke dual-line fuel injection system that uses a mixture of heavy fuel oil and lubricating oil in a specific ratio. By adjusting the ratio of manifold fuel injection to air-assisted fuel injection, lubrication of the piston and connecting rod moving parts is ensured. Furthermore, by using an oil-air mixing chamber with a filter, the cleanliness of the compressed air is guaranteed, thereby improving the reliability of air-assisted injection.

[0006] In order to achieve the above technical objectives, the present invention provides the following technical solutions: The two-stroke dual-path fuel injection system provided by the present invention is divided into a direct injection circuit and a manifold circuit. It includes a manifold fuel injector, an air-assisted injection unit, a pressure-regulating valve, and an air pump. The direct injection circuit includes the air-assisted injection unit, the pressure-regulating valve, and the air pump, while the manifold circuit also includes the manifold fuel injector, the pressure-regulating valve, and the air pump. The air pump is connected to the air-assisted injection unit and the pressure-regulating valve, respectively, to provide an air source to the pressure-regulating valve and the air-assisted injection unit. The air-assisted injection unit includes an air jet, an air-fuel mixing chamber, and a direct injection nozzle. The direct injection nozzle is connected to the pressure-regulating valve; the air-fuel mixing chamber is located between the air jet and the direct injection nozzle.

[0007] The oil outlet of the pressure regulating valve is connected to the manifold oil injector and the air-assisted injection unit respectively, so as to supply oil to the manifold oil injector and the air-assisted injection unit respectively.

[0008] A filter assembly is provided in the oil-gas mixing chamber, which is a filter screen with a filtration accuracy of 20 to 40 microns.

[0009] The present invention also provides an engine comprising an engine body, an oil supply unit, and the aforementioned two-stroke dual-path fuel injection system. The air pump is mounted on the engine body; the oil supply unit is located before the pressure regulating valve and supplies oil to the pressure regulating valve; the oil inlet of the pressure regulating valve is connected to the oil supply unit; the air-assisted injection unit is located at the cylinder head of the engine body; and the manifold fuel injector is mounted on the engine body's intake duct.

[0010] The air pump is mounted on the engine body and pumps air through the crankshaft, providing air power for the pressure regulating valve. The air pump's function is to introduce air into the mixing passage, ensuring thorough mixing of fuel and air to form a combustible mixture. The air pump utilizes the engine's own power source, reducing reliance on external energy sources.

[0011] The fuel supply unit includes a fuel tank, a fuel pump, and a fuel filter. The fuel filter is located between the fuel tank and the fuel pump. The fuel pump is used to pump out the fuel in the fuel tank; the fuel tank is used to store fuel; and the fuel filter is a fine fuel filter with a filtration accuracy of 20-40 microns.

[0012] The manifold oil circuit is connected to the crankcase below the engine body. The manifold oil circuit is connected to the crankcase through a manifold oil injector. On the one hand, it is used to lubricate the internal moving parts of the engine, reduce friction and wear, and extend the life of the engine; on the other hand, it is used to provide additional fuel to improve power.

[0013] The direct injection oil circuit is connected to the combustion chamber above the engine body. A filter assembly installed in this circuit filters the air drawn in by the air pump, removing impurities. The filter assembly typically consists of a filter screen or filter element, and its filtration accuracy can be customized. Through effective filtration, the filter assembly prevents impurities from entering the combustion chamber, preventing wear and clogging of internal engine components and extending the engine's service life. Furthermore, clean air helps maintain combustion stability.

[0014] The direct injection oil circuit is connected to a direct injection fuel injector, which is connected to an oil-gas mixing chamber. The oil-gas mixing chamber is connected to the combustion chamber through an air jet nozzle thereon. An air inlet is provided on the oil-gas mixing chamber, and the air inlet is connected to the air pump.

[0015] Direct injection nozzles inject high-pressure fuel into the fuel-air mixing chamber through the direct injection oil circuit. The fuel mixes with compressed air provided by the air pump, achieving efficient atomization at high injection pressure. Within the fuel-air mixing chamber, the fuel and air fully contact and mix evenly to form a combustible mixture. This significantly improves combustion efficiency, reduces fuel waste, and helps optimize engine power output and combustion stability.

[0016] Furthermore, the fuel-air mixing chamber is connected to the combustion chamber via an air nozzle, which precisely injects the already mixed fuel-air mixture into the combustion chamber at a timely and quantitative rate. This nozzle promotes secondary atomization of the air and fuel, helping to ensure a thorough and efficient combustion process, further improving the engine's combustion efficiency.

[0017] The filter assembly includes a filter screen and an intake duct. The filter screen is mounted on the intake duct, which connects the air pump to the oil-gas mixing chamber. The filter assembly primarily filters the air entering the oil-gas mixing chamber through the filter screen. The filter screen has a filtration accuracy of 20-40 microns, ensuring that larger impurities and dust are effectively removed, thereby ensuring the quality of the air entering the oil-gas mixing chamber.

[0018] The air nozzle, mounted on the top of the combustion chamber, injects the secondary atomized fuel and air from the fuel-air mixing chamber into the combustion chamber, ensuring even distribution of the injected fuel and air throughout the combustion chamber and promoting optimal combustion. Through optimal injection angles and positions, the mixed gas within the combustion chamber is fully ignited, improving combustion efficiency and ensuring a stable combustion process.

[0019] The direct-injection nozzle's injection orifice is no more than half the size of the air jet nozzle. This smaller orifice helps atomize the fuel into finer droplets, thereby improving fuel atomization. This facilitates more complete mixing of fuel and air, enhancing combustion efficiency, avoiding localized over-rich or over-lean combustion, and reducing incomplete combustion and harmful emissions. The air jet nozzle, with its larger orifice and central location at the top of the combustion chamber, further atomizes and injects the fuel, already mixed with compressed air, at low pressure.

[0020] The high-pressure fuel is a mixture of heavy oil and lubricating oil in a ratio of 20:1 to 50:1 to ensure lubrication of moving parts such as pistons and connecting rods. The heavy oil primarily provides energy, while the lubricating oil provides lubrication and cooling. This blended fuel effectively adheres to moving parts such as the piston and connecting rod, forming a lubricating film that reduces friction between metal parts and prevents wear and overheating. Furthermore, the blended fuel dissipates some heat, ensuring that moving parts do not overheat during high-load operation.

[0021] The oil outlet of the fuel tank is connected to a fuel filter, which is then connected to a fuel pump. The filter is responsible for filtering impurities in the fuel. By removing particles and contaminants in the fuel, the fuel filter effectively protects the oil pump, pressure regulating valve, and various components of the fuel injection system, reducing blockage and wear caused by impurities and extending the service life of the system.

[0022] The air pump is connected to the piston pump on the engine body, and pumps compressed air through the movement of the crankshaft in the crankcase, thereby realizing the air supply inside the engine and ensuring the normal operation of the air-assisted injection system; the air pump is driven by the power of the engine and does not require an additional external power source, which simplifies the structure of the system.

[0023] The beneficial effects of the present invention are as follows: 1. This invention utilizes a filter-equipped oil-air mixing chamber and dual fuel injection design to improve the reliability of air-assisted injection and the lubrication of moving parts such as the piston and connecting rod. It also effectively removes solid particles from the air through the physical filtration filter, preventing nozzle clogging and wear, thereby achieving effective lubrication and combustion optimization for various engine components. This invention ensures lubrication of the piston and connecting rod moving parts by adjusting the ratio of manifold injection to air-assisted injection. Furthermore, the use of a filter-equipped oil-air mixing chamber ensures the cleanliness of the compressed air, further improving the reliability of air-assisted injection.

[0024] 2. The present invention uses a dynamic adjustment mechanism to ensure that the engine can obtain proper lubrication under different operating conditions, thereby improving the reliability and durability of the engine. Under medium and low load conditions, the fuel injected by the manifold injectors accounts for 10% to 20% of the total fuel injection volume, effectively providing lubrication for moving parts such as pistons and connecting rods, reducing wear; under high load conditions, the injection ratio of the manifold injectors is increased to more than 30%, ensuring that the lubrication requirements can be met under high loads and further achieving the power requirements.

[0025] 3. The present invention utilizes nozzles of varying diameters, with the air jet connected to the direct injection nozzle and air pump piping via an oil-air mixing chamber. This jet injects the oil-air mixture into the combustion chamber, achieving a double atomization process. First, the fuel injected from the high-pressure nozzle mixes with compressed air in the oil-air mixing chamber, forming a preliminary atomization process. The fuel is then injected into the combustion chamber through the air jet for further atomization, ensuring thorough mixing of the fuel and air. This dual atomization mechanism improves combustion efficiency, promotes complete combustion of the fuel, and reduces fuel consumption and emissions. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0027] The above and other aspects of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 It is a schematic diagram of the present invention; Figure 2 is a cross-sectional view of the present invention; In the figure: 1. Fuel tank; 2. Fuel filter; 3. Fuel pump; 4. Pressure regulating valve; 41. Manifold oil circuit; 42. Direct injection oil circuit; 43. Pressure regulating return oil circuit; 44. Pressure regulating inlet oil circuit; 5. Manifold fuel injector; 6. Direct injection fuel injector; 7. Oil-gas mixing chamber; 71. Intake pipe; 72. Filter; 8. Injector nozzle; 9. Air pump; 91. Pressure regulating intake pipe; 92. Oil-gas mixing intake pipe; 10. Engine body. DETAILED DESCRIPTION

[0028] In order to better understand the above technical solution, the above technical solution will be described in detail below with reference to the accompanying drawings and specific implementation methods.

[0029] The engine with a two-stroke dual-way fuel injection system provided in this embodiment includes a fuel tank 1, a fuel filter 2, a fuel pump 3, a manifold fuel injector 5, an air jet nozzle 8 and a direct injection fuel injector 6, a pressure regulating valve 4 and an air pump 9.

[0030] A fuel filter 2 is provided between the fuel tank 1 and the fuel pump 3. In this embodiment, the fuel filter 2 is a fine fuel filter, which can better filter out larger impurities in the fuel and protect the fuel system. The fuel filter 2 has a filtration accuracy of 20 to 40 microns.

[0031] The air jet nozzle 8 is mounted on the cylinder head of the engine body, and an oil-gas mixing chamber 7 is formed between the air jet nozzle 8 and the direct injection nozzle 6. The direct injection nozzle 6 is connected to the oil outlet of the pressure regulating valve 4.

[0032] In this embodiment, the air pump 9 is connected to the oil-gas mixing chamber 7 and the pressure regulating valve 4 respectively, and supplies air to the pressure regulating valve 4 and the oil-gas mixing chamber 7 respectively through the pressure regulating air inlet pipe 91 and the oil-gas mixing air inlet pipe 92.

[0033] The oil inlet of the pressure regulating valve 4 is connected to the engine's oil pump 3 through the pressure regulating oil inlet line 44, and the oil outlet of the pressure regulating valve 4 is connected to the manifold injector 5 and the direct injection injector 6 through the manifold oil line 41 and the direct injection oil line 42 respectively, and supplies fuel to the above two injectors.

[0034] In this embodiment, the present invention further provides an engine comprising an engine body 10, a fuel supply unit, and the aforementioned system. The fuel supply unit comprises an oil pump 3 for pumping fuel from a fuel tank 1, the outlet of which is connected to a fuel filter 2. An air pump 9 is integrated into the engine body 10 and pumps air through the motion of the crankshaft within the crankcase. A pressure regulating valve 4 regulates fuel pressure and divides the high-pressure fuel into two routes: a manifold and a direct injection route, which are then introduced into the engine body.

[0035] In this embodiment, the fuel filter 2 is located after the fuel outlet of the fuel tank 1; the fuel pump 3 for delivering fuel from the fuel tank is located after the fuel filter; the pressure regulating valve 4 for regulating the fuel pressure is located between the fuel pump 3 and the manifold injectors 5 and the direct injection injectors 6; the air pump 9 for providing an air source to the pressure regulating valve 4 is installed on the engine body.

[0036] In this embodiment, the filter assembly on the oil-gas mixing chamber 7 includes a filter screen 72 and an air intake pipe 71. The filter screen 72 is installed at the air inlet of the air intake pipe 71. The air intake pipe 71 is used to connect the air pump 9 and the oil-gas mixing chamber 7. The filtration accuracy of the filter screen is 20-40 microns.

[0037] In this embodiment, the manifold fuel injector 5 is connected to the crankcase to play the role of lubrication and auxiliary increase of work. The direct injection fuel injector 6 is mainly used for work.

[0038] In this embodiment, a manifold injector 5 for port injection is installed in the engine's intake duct and connected to a pressure regulating valve 4. A direct injection injector 6 is connected to the pressure regulating valve 4, and an air jet 8 is connected to the direct injection injector 6 via an oil-air mixing chamber 7. Air jet 8 is installed at the top of the combustion chamber. The fuel is a mixture of heavy fuel oil and lubricating oil in a ratio of 20:1 to 50:1.

[0039] Through the above-described arrangement, the present invention enables a large proportion of heavy fuel oil, often characterized by high viscosity and poor atomization, to be injected into the cylinder via the air-assisted injection system. This process, through two rounds of friction with the compressed air, allows for better fragmentation and atomization, resulting in a more uniform mixture. Simultaneously, a smaller proportion of heavy fuel oil is injected into the intake duct via the manifold injector 5, where it enters the cylinder along with fresh air through the crankcase. This fuel oil cools and lubricates moving parts, such as the piston and connecting rod. This solution improves combustion efficiency and reduces fuel consumption, while ensuring good lubrication of moving parts and extending their service life.

[0040] During operation, fuel flows from the fuel tank 1 through the fuel outlet into the fuel filter 2, which filters impurities from the fuel to ensure fuel cleanliness. The filtered fuel then enters the fuel pump 3, where it is pumped to the pressure regulating valve 4, where it maintains a constant pressure. An air pump 9, connected to the engine's crankshaft and powered by the engine's crankshaft, generates a compressed air source, which is then supplied to the oil-air mixing chamber 7 and the pressure regulating valve 4.

[0041] Fuel delivered by fuel pump 3 enters pressure regulating valve 4, which regulates the fuel pressure and distributes it to manifold oil passage 41 and direct injection oil passage 42, where it enters different parts of the engine. The function of the pressure regulating valve is to ensure that high-pressure fuel is distributed to each passage at the required pressure.

[0042] Furthermore, the oil-air mixing chamber 7 mixes the high-pressure fuel with air before injecting it into the combustion chamber through the air jet nozzle, achieving secondary atomization. Direct-injection fuel injectors 6 inject fuel into the oil-air mixing chamber 7, while manifold fuel injectors 5 inject fuel directly into the intake duct and into the combustion chamber. The fuel and air are thoroughly mixed in the combustion chamber and ignited, completing the combustion process. After heavy fuel oil and lubricating oil are mixed in a ratio of 20:1 to 50:1, a small proportion of fuel is delivered through the manifold oil circuit to the engine's moving parts, such as pistons and connecting rods, for lubrication. During this process, the lubricating oil provides a lubricating film, reducing friction, preventing overheating, and dissipating some of the heat from the moving parts.

[0043] It's important to note that the fuel filter 2 must ensure sufficient filtration to effectively remove larger particles and impurities, preventing them from entering the fuel pump 3 and pressure regulating valve 4 and causing blockage or wear. Fuel filter 2 is a fine filter with a filtration accuracy of 20-40 microns. Regular inspection and replacement are required to ensure proper function. Furthermore, fuel injection from the air nozzle 8 and direct injection injector 6 must ensure optimal injection angle, flow rate, and atomization of the sprayed fuel particles to avoid incomplete combustion or locally enriched mixtures.

[0044] In addition, special attention should be paid to the matching of the injection diameter and the injection accuracy. An excessively large injection diameter may cause uneven injection and affect the combustion effect. In this embodiment, the injection diameter of the direct injection nozzle 6 is half of that of the air nozzle 8.

[0045] The description herein is provided to enable one of ordinary skill in the art to implement or use the present disclosure. Various modifications to the present disclosure will be apparent to one of ordinary skill in the art, and the overall principles defined herein may be applied to other variations without departing from the scope of the present disclosure. Therefore, the present disclosure is not limited to the examples and designs described herein, but should be given the widest scope consistent with the principles and novel features disclosed herein.

[0046] Although one or more exemplary embodiments of the present disclosure have been described with reference to the drawings, persons skilled in the art will understand that various changes in form and details may be made therein without departing from the spirit and scope of the disclosure as defined by the following claims.

Claims

1. A two-stroke dual-path fuel injection system, characterized in that: It includes a manifold fuel injector (5), an air-assisted injection unit, a pressure regulating valve (4) and an air pump (9); The air pump (9) is connected to the air-assisted injection unit and the pressure regulating valve (4) respectively, and is used to provide an air source to the pressure regulating valve (4) and the air-assisted injection unit; The oil outlet of the pressure regulating valve (4) is connected to the manifold oil injection nozzle (5) and the air-assisted injection unit, respectively, and is used to supply oil to the manifold oil injection nozzle (5) and the air-assisted injection unit, respectively.

2. The two-stroke dual-channel fuel injection system according to claim 1, characterized in that: The air-assisted injection unit comprises an air jet nozzle (8) and a direct injection fuel injector nozzle (6), and the direct injection fuel injector nozzle (6) is connected to a pressure regulating valve (4); The air jet nozzle (8) and the direct injection fuel injector (6) are connected via an oil-air mixing chamber (7) in the middle.

3. The two-stroke dual-channel fuel injection system according to claim 2, characterized in that: A filter assembly is provided in the oil-gas mixing chamber (7).

4. The two-stroke dual-channel fuel injection system according to claim 3, characterized in that: The filter component is a filter screen (72) with a filtration accuracy of 20 to 40 microns.

5. An engine, comprising an engine body (10), characterized in that: It also includes an oil supply unit and a two-stroke dual-way fuel injection system according to any one of claims 1 to 4, which are mounted on the engine body (10); The oil inlet of the pressure regulating valve (4) is connected to the oil pump (3) of the engine body (10) via a pressure regulating oil inlet passage (44); The air pump (9) is installed in the oil supply unit; The air-assisted injection unit is located at the cylinder head of the engine body (10); The manifold fuel injector (5) is mounted on the air intake duct of the engine body (10).

6. The engine according to claim 5, characterized in that: The oil supply unit comprises an oil tank (1), an oil pump (3) and a fuel filter (2), wherein the fuel filter (2) is arranged between the oil tank (1) and the oil pump (3).

7. The engine according to claim 6, characterized in that: The fuel filter (2) is a fuel fine filter with a filtration accuracy of 20 to 40 microns.

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