Engine and automobile

Abstract

The application provides an engine and a car, wherein the engine comprises a cylinder cover, an intake valve, an exhaust valve and a piston, the cylinder cover has an intake passage and an exhaust passage; the intake valve and the exhaust valve are slidably connected to the cylinder cover. The cylinder is fixedly connected to the cylinder cover. The piston is arranged in the cylinder, and the piston, the cylinder and the cylinder cover enclose a combustion chamber. The ratio of the stroke of the piston to the inner diameter of the cylinder is greater than 1.1 and less than or equal to 1.3, and the compression ratio of the engine is less than or equal to 12. The application can reduce the space for transverse diffusion of the intake airflow, force the airflow to move in the height direction of the combustion chamber, and more easily maintain and enhance the tumble flow movement. At the same time, by reducing the compression ratio, the risk of end mixture reaching the self-ignition temperature can be reduced, the molecular collision energy can be reduced, and the self-ignition reaction can be delayed, so that the temperature and pressure of the mixture in the cylinder at the end of the piston stroke can be effectively reduced, thereby avoiding the knock of the end mixture before the ignition of the spark plug.

Description

Technical Field

[0001] This application relates to the field of vehicle technology, and more particularly to an engine and an automobile. Background Technology

[0002] For existing engines, the piston stroke is close to the cylinder diameter, resulting in a large space for lateral diffusion of the intake airflow. The gas flow rate entering the cylinder is relatively slow, which is not conducive to increasing the tumble ratio and makes it difficult to achieve rapid combustion in the combustion chamber. In addition, existing engines have a high compression ratio, which makes them prone to knocking. Utility Model Content

[0003] The purpose of this application is to provide an engine and a car to solve the problems in the prior art where engines are difficult to achieve rapid combustion in the combustion chamber and are prone to knocking.

[0004] In a first aspect, this application provides an engine, comprising:

[0005] Cylinder head, the cylinder head having an intake manifold and an exhaust manifold;

[0006] An intake valve, slidably connected to the cylinder head, is used to open or close the intake manifold;

[0007] An exhaust valve, slidably connected to the cylinder head, is used to open or close the exhaust passage;

[0008] The cylinder is fixedly connected to the cylinder head;

[0009] A piston is disposed in the cylinder, and the piston, the cylinder, and the cylinder head together form a combustion chamber;

[0010] Wherein, the ratio of the piston stroke to the cylinder bore is greater than 1.1 and less than or equal to 1.3, and the compression ratio of the engine is less than or equal to 12.

[0011] In one possible implementation, the intake valve and the exhaust valve are respectively disposed on both sides of the piston axis C, and the intake valve and the exhaust valve are inclined relative to the piston axis.

[0012] In one possible implementation, the included angle α between the intake valve and the exhaust valve is greater than or equal to 20° and less than or equal to 40°.

[0013] In one possible implementation, there are two intake ports, and the surface of the region M on the cylinder head located between the two intake ports is a smooth surface.

[0014] In one possible implementation, the engine further includes a crankshaft and an intake camshaft, the crankshaft being connected to the intake camshaft, and the intake camshaft having a cam for driving the intake valve movement.

[0015] In one possible implementation, the cam has an arcuate protrusion with a wrap angle β of 100°±5°.

[0016] In one possible implementation, when the crankshaft angle is 130°±5° before the top dead center of the intake stroke, the intake valve has a first lift, the first lift being between 0.9 mm and 1.1 mm; the top dead center of the intake stroke is the position where the crankshaft mates with the end of the arc-shaped protrusion.

[0017] In one possible implementation, the intake valve has a second lift, which is between 0.9 mm and 1.1 mm, when the crankshaft angle is 230° ± 5° after the top dead center of the intake stroke.

[0018] In one possible implementation, the maximum lift of the intake valve is between 8.0 mm and 10.0 mm.

[0019] Secondly, embodiments of this application also provide an automobile, which includes the engine provided in the first aspect of this application.

[0020] The technical solution provided in this application can achieve the following beneficial effects:

[0021] The engine and automobile provided in this application, by having a piston stroke in one direction with a ratio to the cylinder bore greater than 1.1 and less than or equal to 1.3, and an engine compression ratio less than or equal to 12, can reduce the space for lateral diffusion of intake airflow, forcing the airflow to move in the height direction of the combustion chamber, making it easier to maintain and enhance tumble motion. The longer piston stroke provides a longer axial development space for the tumble vortex. Due to the increased stroke, at a faster piston speed, the gas velocity entering the cylinder also increases, thereby increasing turbulence in the combustion chamber, improving the tumble ratio, and ensuring thorough mixing of fuel and air, thus achieving rapid combustion. Simultaneously, by reducing the compression ratio, the risk of the final mixture reaching auto-ignition temperature can be reduced, molecular collision energy can be lowered, and the auto-ignition reaction can be delayed. Therefore, reducing the compression ratio can effectively reduce the temperature and pressure of the mixture in the cylinder at the end of the piston stroke, thereby preventing knocking of the final mixture before spark plug ignition.

[0022] It should be understood that the above general description and the following detailed description are merely exemplary and do not limit this application. Attached Figure Description

[0023] Figure 1 A partial schematic diagram of an engine provided in an embodiment of this application;

[0024] Figure 2 This is a schematic diagram of the tumble flow field in an engine provided in one embodiment of this application;

[0025] Figure 3 A schematic diagram of the tumble flow field in an engine provided for another embodiment of this application;

[0026] Figure 4 A partial structural diagram of the cylinder head in an engine provided in an embodiment of this application;

[0027] Figure 5 This is a front view of the cam in an engine provided in an embodiment of this application;

[0028] Figure 6 This is a schematic diagram of the intake camshaft profile in an engine provided in an embodiment of this application;

[0029] Figure 7 A graph showing the external characteristic torque of the engine provided in the embodiments of this application.

[0030] Figure label:

[0031] 1-Cylinder head; 11-Intake manifold; 12-Exhaust manifold; 13-First guide hole; 14-Second guide hole;

[0032] 2-Cylinder;

[0033] 3-Intake valve;

[0034] 4-Exhaust valve;

[0035] 5-Piston;

[0036] 6-Combustion chamber;

[0037] 7-Cam; 71-Arc-shaped protrusion; 71a-First end; 72a-Second end.

[0038] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0040] In the description of this application, unless otherwise expressly specified and limited, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance; unless otherwise specified or explained, the term "multiple" refers to two or more; 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; it 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.

[0041] In the description of this specification, it should be understood that the directional terms such as "upper" and "lower" used in the embodiments of this application are used to describe the angles shown in the accompanying drawings and should not be construed as limiting the embodiments of this application. Furthermore, in the context, it should also be understood that when it is mentioned that an element is connected "upper" or "lower" to another element, it can be directly connected to the other element "upper" or "lower," or indirectly connected to the other element "upper" or "lower" through an intermediate element.

[0042] For existing direct-drive fuel engines, the piston stroke is close to the cylinder bore. This results in a large space for the lateral diffusion of the intake airflow in the cylinder, and a slow gas flow rate into the cylinder. This is not conducive to increasing turbulence in the combustion chamber, nor to increasing the tumble ratio. As a result, the fuel and air are difficult to mix fully and achieve rapid combustion.

[0043] Current engines have a high compression ratio, making them prone to knocking. During the compression stroke, after the spark plug ignites the air-fuel mixture, the flame front propagates normally, but the unburned portion of the mixture at the end ignites spontaneously under high temperature and pressure, creating multiple combustion points. The collision of these two flames generates a shock wave that impacts the cylinder walls and piston, producing a metallic knocking sound (i.e., knocking). The higher the compression ratio, the greater the degree of compression of the air-fuel mixture, the more significant the temperature rise, and the more pronounced the tendency for knocking.

[0044] In view of this, the present application provides an engine to solve the problems in the prior art where it is difficult to achieve rapid combustion in the combustion chamber and knocking is prone to occur.

[0045] Figure 1 A partial schematic diagram of the engine provided in the embodiments of this application, such as... Figure 1As shown, the engine can be a direct-drive fuel engine, which includes a cylinder head 1, a cylinder 2, an intake valve 3, an exhaust valve 4, and a piston 5. The cylinder head 1 has an intake manifold 11 and an exhaust manifold 12. The intake valve 3 is slidably connected to the cylinder head 1 for opening or closing the intake manifold 11. The exhaust valve 4 is slidably connected to the cylinder head 1 for opening or closing the exhaust manifold 12. The cylinder 2 is fixedly connected to the cylinder head 1, and the piston 5 is disposed in the cylinder 2. The piston 5, the cylinder 2, and the cylinder head 1 together form a combustion chamber 6.

[0046] The intake manifold 11 and exhaust manifold 12 are located inside the cylinder head 1. The cylinder head 1 has a first guide hole 13 and a second guide hole 14. The intake valve 3 is slidably engaged with the first guide hole 13, and the exhaust valve 4 is slidably engaged with the second guide hole 14. The intake valve 3 controls the opening or closing of the intake manifold 11 by its own movement, and the exhaust valve 4 controls the opening or closing of the exhaust manifold 12 by its own movement, so as to realize the flow of gas in the cylinder 2, so that the gas can be mixed with fuel and improve the combustion efficiency of fuel.

[0047] The engine has four strokes: intake stroke, compression stroke, power stroke, and exhaust stroke.

[0048] The intake stroke allows fresh air or a combustible mixture to be drawn into cylinder 2. Specifically, piston 5 moves downward from the top (top dead center) of cylinder 2. During this process, intake valve 3 is open and exhaust valve 4 is closed. The downward movement of piston 5 creates a vacuum (negative pressure) within cylinder 2. Fresh air or a combustible mixture is drawn into cylinder 2 through intake manifold 11 and the open intake valve 3.

[0049] The compression stroke compresses the gas inside cylinder 2, preparing it for combustion. Specifically, piston 5 moves upward from the bottom (bottom dead center) of cylinder 2. During this process, intake valve 3 and exhaust valve 4 are closed, creating a sealed space inside cylinder 2 to ensure that gas does not flow back into intake manifold 11 and does not leak into exhaust manifold 12. The upward-moving piston 5 compresses the gas enclosed within cylinder 2.

[0050] During the power stroke, the air-fuel mixture is burned, generating enormous pressure that pushes piston 5 to output power. Specifically, at the end of the compression stroke, the spark plug ignites the mixture, causing it to burn rapidly and produce high temperature and pressure. With intake valve 3 and exhaust valve 4 closed, the high-pressure gas violently pushes piston 5 downwards. Piston 5 transmits this force to the crankshaft via the connecting rod, thus providing the car's power source.

[0051] The exhaust stroke allows the exhaust gases from the cylinder 2 to be expelled, preparing for the intake of fresh air in the next cycle. Specifically, the piston 5 moves upward from the bottom dead center. During this process, the intake valve 3 is closed and the exhaust valve 4 is open. The upward-moving piston 5 pushes the exhaust gases in the cylinder 2 into the exhaust passage 12 through the open exhaust valve 4, and finally into the atmosphere through the exhaust pipe and muffler.

[0052] In this embodiment, the ratio of the piston 5's stroke in a single direction to the cylinder 2's inner diameter is greater than 1.1 and less than or equal to 1.3, and the engine's compression ratio is less than or equal to 12. Specifically, by increasing the size of the piston 5 and / or decreasing the cylinder 2's inner diameter, the height of the combustion chamber 6 can be greater than its inner diameter. In this embodiment, the ratio of the piston 5's stroke in a single direction to the cylinder 2's inner diameter can be, but is not limited to, 1.1, 1.2, 1.28, or 1.3. The inner diameter of the combustion chamber 6 restricts the space for lateral diffusion of the intake airflow, forcing the airflow to move in the height direction of the combustion chamber 6, making it easier to maintain and enhance tumble motion. The larger stroke of the piston 5 provides a longer axial development space for the tumble vortex. Due to the increased stroke, at a faster piston 5 operating speed, the gas velocity entering the cylinder 2 also increases, thereby increasing turbulence within the combustion chamber 6, improving the tumble ratio, and ensuring thorough mixing of fuel and air, thus achieving rapid combustion.

[0053] By ensuring that the ratio of the piston 5's stroke in a single direction to the cylinder 2's inner diameter is greater than 1.1 and less than or equal to 1.3, the engine's compression ratio can be reduced to 12 or less. Lowering the compression ratio reduces the risk of the final air-fuel mixture reaching auto-ignition temperature, reduces molecular collision energy, and delays the auto-ignition reaction. Therefore, lowering the compression ratio effectively reduces the temperature and pressure of the air-fuel mixture in cylinder 2 at the end of the piston 5's stroke, thus preventing knocking of the final air-fuel mixture before spark plug ignition.

[0054] The intake valve 3 and exhaust valve 4 are respectively located on both sides of the axis C of the piston 5, and the intake valve 3 and exhaust valve 4 are inclined relative to the axis C of the piston 5. The inclined intake valve 3 and exhaust valve 4 can make the top (roof) of the combustion chamber 6 form an approximately triangular shape, thereby effectively guiding the intake airflow to a specific area on the top of the piston 5, enhancing the strength and stability of the tumble flow.

[0055] An angle α exists between the intake valve 3 and the exhaust valve 4. If this angle α is too large, it may weaken the tumble flow, leading to incomplete combustion and low combustion efficiency. Therefore, in this embodiment, the angle α can be greater than or equal to 20° and less than or equal to 40°. Exemplarily, the angle α can be, but is not limited to, 20°, 25°, 30°, 35°, or 40°. The roof of the combustion chamber 6, formed by the inclined intake valve 3 and exhaust valve 4, combined with the aforementioned smaller angle α formed between the intake valve 3 and exhaust valve 4, can more effectively guide the intake airflow to a specific area on the top of the piston 5, enhancing the strength and stability of the tumble flow, which is beneficial for achieving more efficient and complete combustion.

[0056] The enhanced intake airflow forms a strong and orderly vertical rotating vortex (tumble flow) in cylinder 2. At the end of the compression stroke, the strong tumble flow breaks into small-scale, high-intensity turbulence (micro-vortex). The high-intensity turbulence greatly increases the flame front area and combustion rate, making combustion faster and more complete. The rapid combustion is closer to the ideal isochoric combustion cycle, reducing pumping losses and heat transfer losses, and improving indicated thermal efficiency.

[0057] Figure 2 This is a schematic diagram of the tumble flow field in an engine according to one embodiment of this application. Figure 2 The tumble flow field is illustrated exemplarily when the crankshaft angle is 654°, by Figure 2 It can be seen that the tumble flow field is uniformly distributed and the flow direction is uniform and consistent, all flowing in the circumferential direction.

[0058] Figure 3 This is a schematic diagram of the tumble flow field in an engine provided by another embodiment of this application. Figure 3 The tumble flow field is illustrated exemplarily when the crankshaft angle is 459°, by Figure 3 It can be seen that the tumble flow field is uniformly distributed and the flow direction is uniform and consistent, all flowing in the circumferential direction.

[0059] During the machining of cylinder head 1, intake manifold 11 and exhaust manifold 12 need to be machined on cylinder head 1. After machining intake manifold 11 and exhaust manifold 12, sharp edges will be formed near intake manifold 11. For example, sharp edges are easily formed at the edge of intake manifold 11. The thickness of such sharp edges is very small. Under high temperature and high pressure, they can be easily ignited to form hot spots. These hot spots can lead to knocking.

[0060] Therefore, in this embodiment, Figure 4 This is a partial structural diagram of the cylinder head 1 in the engine provided in an embodiment of this application, as shown below. Figure 4As shown, both the intake manifold 11 and the exhaust manifold 12 are provided in twos. The surface of the region M on the cylinder head 1 located between the two intake manifolds 11 is a smooth surface. This smooth surface can be a smooth plane or a smooth curved surface. There are no sharp edges in this region M, which can effectively prevent edge combustion and the formation of hot spots, thus reducing the tendency for knocking.

[0061] The engine also includes a crankshaft and an intake camshaft 7-axis. The crankshaft is connected to the intake camshaft 7-axis. For example, both the crankshaft and the intake camshaft 7-axis are equipped with timing gears. Both timing gears on the crankshaft and the intake camshaft 7-axis can mesh with a timing belt to achieve power transmission between the crankshaft and the intake camshaft 7-axis. The crankshaft controls the rotation of the intake camshaft 7-axis. The number of teeth on the intake camshaft 7-axis timing gear is twice the number of teeth on the crankshaft timing gear, achieving a crankshaft speed to intake camshaft speed ratio of 2:1.

[0062] Figure 5 This is a front view of the cam 7 in the engine provided in the embodiment of this application, as shown below. Figure 5 As shown, a cam 7 is provided on the intake cam 7 shaft, and the cam 7 is used to drive the intake valve 3 to move. The cam 7 is not circular, and the radial distance between different positions on the side surface of the cam 7 and the axis of the intake cam 7 shaft is different. For example, the cam 7 has an arc-shaped protrusion 71. The radial distance between the side surface of the arc-shaped protrusion 71 and the axis of the intake cam 7 shaft is greater than the radial distance between the side surface of the non-arc-shaped protrusion 71 on the cam 7 and the axis of the intake cam 7 shaft. Therefore, as the cam 7 rotates with the intake cam 7 shaft, it can drive the intake valve 3 to make linear motion.

[0063] like Figure 5 As shown, the wrap angle β of the arc-shaped protrusion 71 is 100°±5°. Since the ratio of the crankshaft speed to the intake camshaft speed is 2:1, for example, the crankshaft rotates two revolutions for every one revolution of the camshaft 7. When the angle of rotation of the cam 7 is the wrap angle β, for example, when the angle of rotation of the cam 7 is 100°, the crankshaft rotates 200° accordingly. As the part of the cam 7 that interacts with the intake valve 3 rotates along the surface of the arc-shaped protrusion 71 from the first end 71a to the second end 72a, the intake valve 3 completes one opening and closing, that is, the engine completes one intake stroke. Since the wrap angle β of the arc-shaped protrusion 71 is 100°±5°, the crankshaft rotates through an angle close to 200°. That is, during the completion of one intake stroke, the crankshaft rotates through a small angle, which can achieve explosive output of mechanical energy in a very short time, so that the intake valve 3 can obtain a faster opening speed, maximize the use of the limited time window and airflow inertia effect, increase the intake volume, and improve high-speed power.

[0064] Figure 6This is a schematic diagram of the intake camshaft profile 7 in an engine provided in an embodiment of this application. The horizontal axis represents the crankshaft rotation angle, and the vertical axis represents the intake valve lift 3. Figure 6 As shown, when the crankshaft angle is 130°±5° before the top dead center of the intake stroke, the intake valve 3 has a first lift, which is between 0.9mm and 1.1mm. For example, the first lift is, but not limited to, 0.9mm, 1mm, or 1.1mm. The top dead center of the intake stroke is the position where the crankshaft mates with the end of the arc-shaped protrusion 71. Figure 5 When the first end 71a of the arc-shaped protrusion 71 begins to engage with the intake valve 3, the intake valve 3 already has a certain lift (first lift), that is, the intake valve 3 has already opened slightly in advance.

[0065] When the crankshaft angle is between 130° and 230° after the top dead center of the intake stroke, the engine is in the intake stroke phase. During this process, cylinder 2 can draw in fresh air or an air-fuel mixture.

[0066] When the crankshaft angle is 230°±5° after the top dead center of the intake stroke, the intake valve 3 has a second lift, which is between 0.9mm and 1.1mm, for example, but not limited to 0.9mm, 1mm, or 1.1mm. Figure 5 When the second end 72a of the arc-shaped protrusion 71 engages with the intake valve 3, the intake valve 3 still has a certain lift (second lift), that is, the intake valve 3 closes with a delay.

[0067] Therefore, by opening the intake valve 3 earlier and closing it later, the intake stroke can have a longer duration, which is beneficial to maximizing the use of the limited time window and airflow inertia effect, increasing the intake volume, and improving high-speed power.

[0068] In this embodiment, the maximum lift of the intake valve 3 is between 8.0 mm and 10.0 mm. The intake valve 3 has a large lift, which can reduce the flow rate and resistance of air flowing into the cylinder 2, reduce pumping losses, and make the intake process smoother and more efficient.

[0069] Figure 7 This is a graph of the external characteristic torque of the engine provided in the embodiments of this application, with the horizontal axis representing speed and the vertical axis representing torque. Figure 7 As shown, for a 1.5L engine, the maximum torque can reach 140Nm at 4000rpm. The torque also meets requirements at other engine speeds.

[0070] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. An engine, characterized in that, include: Cylinder head (1), the cylinder head (1) having an intake manifold (11) and an exhaust manifold (12); The intake valve (3) is slidably connected to the cylinder head (1) and is used to open or close the intake passage (11); An exhaust valve (4) is slidably connected to the cylinder head (1) and is used to open or close the exhaust passage (12); Cylinder (2), which is fixedly connected to the cylinder head (1); A piston (5) is disposed in the cylinder (2), and the piston (5), the cylinder (2) and the cylinder head (1) enclose a combustion chamber (6); Wherein, the ratio of the stroke of the piston (5) to the inner diameter of the cylinder (2) is greater than 1.1 and less than or equal to 1.3, and the compression ratio of the engine is less than or equal to 12.

2. The engine according to claim 1, characterized in that, The intake valve (3) and the exhaust valve (4) are respectively disposed on both sides of the axis C of the piston (5), and the intake valve (3) and the exhaust valve (4) are inclined relative to the axis of the piston (5).

3. The engine according to claim 2, characterized in that, The included angle α between the intake valve (3) and the exhaust valve (4) is greater than or equal to 20° and less than or equal to 40°.

4. The engine according to claim 1, characterized in that, The intake manifold (11) is provided in two parts, and the surface of the region M on the cylinder head (1) located between the two intake manifolds (11) is a smooth surface.

5. The engine according to claim 1, characterized in that, It also includes a crankshaft and an intake cam (7) shaft, the crankshaft being connected to the intake cam (7) shaft, the intake cam (7) shaft being provided with a cam (7) for driving the intake valve (3) to move.

6. The engine according to claim 5, characterized in that, The cam (7) has an arc-shaped protrusion (71) with a wrap angle β of 100°±5°.

7. The engine according to claim 6, characterized in that, When the crankshaft angle is 130°±5° before the top dead center of the intake stroke, the intake valve (3) has a first lift, which is between 0.9mm and 1.1mm; the top dead center of the intake stroke is the position where the crankshaft mates with the end of the arc-shaped protrusion (71).

8. The engine according to claim 7, characterized in that, When the crankshaft angle is 230°±5° after the top dead center of the intake stroke, the intake valve (3) has a second lift, which is between 0.9 mm and 1.1 mm.

9. The engine according to claim 1, characterized in that, The maximum lift of the intake valve (3) is between 8.0 mm and 10.0 mm.

10. A car, characterized in that, Includes the engine as described in any one of claims 1-9.

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