A spark-ignition two-stroke heavy-duty direct-injection engine combustion chamber

Abstract

This invention relates to the field of engine technology, specifically disclosing a combustion chamber for a spark-ignition two-stroke heavy-duty direct-injection engine. The combustion chamber includes: an injection chamber, an ignition chamber connected to the injection chamber on one side, an intermediate chamber between the piston top and the bottom of the combustion chamber, a first mounting hole, a second mounting hole, and a transition chamber connected to the other side of the ignition chamber. By designing the combustion chamber as a curved structure from high to low, this invention creates air turbulence within the combustion chamber when the cylinder compresses air. This not only improves the binding effect between the heavy-duty fuel mist and air but also enhances the airflow within the combustion chamber, accelerating the flame propagation speed during combustion. Furthermore, the air turbulence converges at the main combustion hole of the spark plug, reducing carbon buildup at the main combustion hole. Furthermore, by placing the combustion chamber within the cylinder head, it not only accelerates the formation time of air turbulence and improves the combustion efficiency of the combustion chamber but also reduces the piston's rotational inertia, thereby improving the overall performance of the engine.

Description

Technical Field

[0001] This invention belongs to the field of engine technology, and specifically relates to a combustion chamber of a spark-ignition two-stroke heavy-duty direct injection engine. Background Technology

[0002] Spark-ignition piston engines, especially two-stroke engines, are widely used in military special vehicles and small and medium-sized unmanned helicopters due to their advantages such as simple mechanical structure, high efficiency, light weight, and high power output. Compared with gasoline, heavy oil has a higher flash point, better safety, and is easier to transport; however, it has a lower flame propagation speed and poorer anti-knock properties during combustion. Knock is an abnormal combustion phenomenon in spark-ignition engines, which can severely affect power output, increase fuel consumption, and even damage important engine components. Furthermore, due to poor airflow, carbon deposits easily form at the spark plug ignition point during combustion in a conventional combustion chamber, leading to spark plug damage and seriously affecting engine ignition performance. Especially given the low flame propagation speed of heavy oil combustion, achieving high airflow in the combustion chamber is extremely important. Summary of the Invention

[0003] The purpose of this invention is to provide a spark-ignition two-stroke heavy oil direct injection engine combustion chamber, thereby overcoming the defects of poor flame propagation speed and easy knocking caused by poor air flow in the combustion chamber during heavy oil engine combustion; and also overcoming the defect of easy carbon buildup in the main combustion hole of the spark plug caused by poor air flow in the combustion chamber.

[0004] To achieve the above objectives, the present invention provides a combustion chamber for a spark-ignition two-stroke heavy-duty direct-injection engine, comprising: an injection chamber disposed in the engine cylinder head, wherein the injection chamber wall is curved and the chamber opening faces downward, and the top of the injection chamber is provided with a first mounting hole, wherein an auxiliary gas metering injection valve is installed in the first mounting hole with the nozzle facing downward; an ignition chamber disposed in the engine cylinder head, wherein one side of the ignition chamber is connected to the injection chamber, wherein the ignition chamber wall is curved and the chamber opening faces downward, and the top of the ignition chamber is symmetrically provided with two second mounting holes, wherein a spark plug is installed in the second mounting holes with the main combustion hole facing downward; the maximum height inside the ignition chamber is lower than the maximum height inside the injection chamber; and an intermediate chamber, which is the area formed by the piston top and the bottom of the combustion chamber when the engine piston reaches top dead center; a transition chamber is also provided on the other side of the ignition chamber, which is interconnected with the ignition chamber, wherein the transition chamber wall is curved and the chamber opening faces downward, and the maximum height inside the transition chamber is lower than the maximum height of the ignition chamber.

[0005] Preferably, in the above technical solution, the axes of the two second mounting holes intersect each other and the intersection point falls within the ignition cavity.

[0006] Preferably, in the above technical solution, the included angle between the axes of the two second mounting holes is 30 degrees to 320 degrees.

[0007] Preferably, in the above technical solution, the angle between the axis of the first mounting hole and the horizontal plane is 15 degrees to 150 degrees.

[0008] Preferably, in the above technical solution, the ratio of the height to the length of the ignition cavity is 1 to 1.5, the ratio of the length to the width of the ignition cavity is 2 to 5, and the ratio of the width to the height of the ignition cavity is 1.5 to 3.

[0009] Preferably, in the above technical solution, the ratio of the length to the height of the injection chamber is 2 to 4, the ratio of the length to the width of the injection chamber is 1 to 2, and the ratio of the width to the height of the injection chamber is 1 to 3.

[0010] Preferably, in the above technical solution, the thickness of the intermediate cavity is 0.5mm to 1.2mm.

[0011] Preferably, in the above technical solution, the ratio of the diameter to the thickness of the intermediate cavity is 3 to 10.

[0012] Compared with existing technologies, the present invention has the following advantages:

[0013] 1. In this invention, the injection chamber, ignition chamber, and transition chamber are all curved structures with progressively decreasing heights. When the piston compresses the gas, turbulence is generated throughout the combustion chamber, which improves the gas flow within the combustion chamber, thereby increasing the combustion speed of heavy oil and reducing knocking.

[0014] 2. In this invention, the fuel injection chamber, ignition chamber, and transition chamber are all located in the cylinder head of the engine. This not only enables turbulence to be generated at the spark plug ignition point and the nozzle of the auxiliary gas metering injection valve at the first moment, but also avoids increasing the thickness of the piston to accommodate the combustion chamber and reduces the piston's rotational inertia.

[0015] 3. The air turbulence formed inside the combustion chamber converges at the ignition chamber, and the air velocity at the main combustion hole of the spark plug increases, making it less likely for carbon deposits to form at the main combustion hole. Attached Figure Description

[0016] Figure 1 This is a structural diagram of the combustion chamber of the spark-ignition two-stroke heavy-duty direct-injection engine of the present invention.

[0017] Figure 2 This is a schematic diagram of the turbulent flow direction in the main view direction of the combustion chamber.

[0018] Figure 3This is a schematic diagram of the turbulent flow direction when viewed from above in the combustion chamber.

[0019] Explanation of key figure labels:

[0020] 1-Injection chamber, 2-First mounting hole, 3-Ignition chamber, 4-Second mounting hole, 5-Intermediate chamber, 6-Transition chamber. Detailed Implementation

[0021] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0022] like Figure 1 As shown, the combustion chamber of a spark-ignition two-stroke heavy-duty direct-injection engine in this embodiment includes: an injection chamber 1, a first mounting hole 2, an ignition chamber 3, a second mounting hole 4, an intermediate chamber 5, and a transition chamber 6. The injection chamber 1 is located in the engine cylinder head, with curved walls and the chamber opening facing downwards on the mounting surface between the engine cylinder head and the cylinder block; the length-to-height ratio of the injection chamber 1 is 2-4, the length-to-width ratio is 1-2, and the width-to-height ratio is 1-3; the first mounting hole 2 is opened at the top of the injection chamber 1, and the auxiliary gas metering injection valve is installed in the first mounting hole 2 with the nozzle facing downwards, and the angle between the axis of the mounting hole 2 and the horizontal plane (the installation angle of the auxiliary gas metering injection valve) is 15 degrees to 150 degrees. Ignition chamber 2 is located in the engine cylinder head, with curved walls and its opening facing downwards on the mounting surface between the engine cylinder head and the cylinder block. One side of ignition chamber 3 is connected to fuel injection chamber 1, and the maximum height of ignition chamber 3 is lower than the maximum height of fuel injection chamber 1. The height-to-length ratio of ignition chamber 3 is 1~1.5, the length-to-width ratio is 2~5, and the width-to-height ratio is 1.5~3. Two second mounting holes 4 are symmetrically provided on the top of ignition chamber 3. Spark plugs are installed in the second mounting holes 3 with the main combustion port facing downwards. The included angle (spark plug installation angle) between the axes of the two mounting holes 4 is 30 degrees to 320 degrees. Intermediate chamber 5 is the area formed by the piston top and the bottom of the combustion chamber when the engine piston reaches top dead center. The thickness of intermediate chamber 5 is 0.5mm to 1.2mm, and the diameter-to-thickness ratio is 3~10. The transition cavity 6 is located on the other side of the ignition cavity 3 and is connected to the ignition cavity 3. The cavity wall of the transition cavity 6 is curved and the cavity opening faces downward. The maximum height inside the cavity is lower than the maximum height of the ignition cavity 3.

[0023] Next, the working principle of the combustion chamber of the spark-ignition two-stroke heavy-duty direct injection engine in this embodiment will be described in detail to enable those skilled in the art to better understand the present invention:

[0024] 1. For example Figure 2 and Figure 3As shown, when the engine piston compresses air, due to the curved surface structure inside the combustion chamber from high to low, a shape is formed in the direction from the injection chamber 1 to the transition chamber 6, as shown in the diagram. Figure 2 The gas turbulence shown in the diagram forms a rolling gas turbulence from the center to both sides inside each cavity, but each gas turbulence will accumulate at the main combustion holes of the two spark plugs.

[0025] 2. Since the combustion chamber is located on the engine cylinder head, gas turbulence is formed in the combustion chamber when the piston begins to move upward to compress the gas (i.e., when the height of the intermediate chamber 5 begins to recede from its maximum), thus improving the efficiency of turbulence formation.

[0026] 3. The auxiliary gas metering injection valve injects atomized heavy oil gas into the combustion chamber, where it is carried by turbulence to the main combustion hole of the spark plug and converges. At the same time, the good gas flow allows the oil mist to mix thoroughly with the air. When the spark plug ignites the oil mist mixture, the air flow speed determines the flame propagation speed. Therefore, the turbulence increases the air flow speed, which in turn increases the flame propagation speed after the oil mist is ignited. This reduces the detonation phenomenon and allows the oil mist to burn completely, slowing down the formation of carbon deposits.

[0027] 4. Because air turbulence can accumulate at the main combustion hole of the spark plug, the air flow at this point is also the best. The main combustion hole is constantly impacted by the airflow, making it less prone to carbon buildup.

[0028] In summary, this invention, by designing the combustion chamber as a curved structure from high to low, creates air turbulence within the combustion chamber when the cylinder compresses air. This not only improves the binding effect between heavy fuel oil mist and air but also enhances airflow within the combustion chamber, accelerating flame propagation during combustion. Furthermore, the air turbulence converges at the main combustion hole of the spark plug, reducing carbon buildup there. Additionally, placing the combustion chamber within the cylinder head further accelerates the formation time of air turbulence, improving combustion efficiency, and reduces piston rotational inertia, thus enhancing overall engine performance.

[0029] The foregoing description of specific exemplary embodiments of the invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A combustion chamber for a spark-ignition two-stroke heavy-duty direct-injection engine, characterized in that, include: The fuel injection chamber (1) is located in the engine cylinder head. The wall of the fuel injection chamber (1) is curved and the cavity opening faces downward. The top of the fuel injection chamber (1) is provided with a first mounting hole (2). The auxiliary gas metering injection valve is installed in the first mounting hole (2) with the nozzle facing downward. The ignition chamber (3) is located in the engine cylinder head. One side of the ignition chamber (3) is connected to the fuel injection chamber (1). The cavity wall of the ignition chamber (3) is curved and the cavity opening faces downward. Two second mounting holes (4) are symmetrically provided on the top of the ignition chamber (3). The spark plug is installed in the second mounting hole (4) with the main combustion hole facing downward. The maximum height inside the ignition chamber (3) is lower than the maximum height inside the fuel injection chamber (1). as well as The intermediate cavity (5) is the area formed by the top of the piston and the bottom of the combustion chamber when the engine piston reaches the top dead center; On the other side of the ignition chamber (3), there is also a transition chamber (6), which is connected to the ignition chamber (3). The wall of the transition chamber (6) is curved and the opening faces downward. The maximum height inside the chamber is lower than the maximum height of the ignition chamber (3).

2. The combustion chamber of the spark-ignition two-stroke heavy-duty direct-injection engine according to claim 1, characterized in that, The axes of the two second mounting holes (4) intersect each other and the intersection point falls within the ignition chamber (3).

3. The combustion chamber of the spark-ignition two-stroke heavy-duty direct-injection engine according to claim 1, characterized in that, The included angle between the axes of the two second mounting holes (4) is 30 degrees to 320 degrees.

4. The combustion chamber of the spark-ignition two-stroke heavy-duty direct-injection engine according to claim 1, characterized in that, The angle between the axis of the first mounting hole (2) and the horizontal plane is 15 to 150 degrees.

5. The combustion chamber of the spark-ignition two-stroke heavy-duty direct-injection engine according to claim 1, characterized in that, The ratio of the height to the length of the ignition chamber (3) is 1 to 1.5, the ratio of the length to the width of the ignition chamber (3) is 2 to 5, and the ratio of the width to the height of the ignition chamber (3) is 1.5 to 3.

6. The combustion chamber of the spark-ignition two-stroke heavy-duty direct-injection engine according to claim 1, characterized in that, The ratio of the length to the height of the fuel injection chamber (1) is 2 to 4, the ratio of the length to the width of the fuel injection chamber (1) is 1 to 2, and the ratio of the width to the height of the fuel injection chamber (1) is 1 to 3.

7. The combustion chamber of the spark-ignition two-stroke heavy-duty direct-injection engine according to claim 1, characterized in that, The thickness of the intermediate cavity (5) is 0.5 mm to 1.2 mm.

8. The combustion chamber of the spark-ignition two-stroke heavy-duty direct-injection engine according to claim 1, characterized in that, The ratio of the diameter to the thickness of the intermediate cavity (5) is 3 to 10.

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