Variable compression ratio piston, bi-fuel engine comprising same and vehicle

Abstract

A variable compression ratio piston, a bi-fuel engine comprising same and a vehicle are disclosed. According to the present disclosure, the variable compression ratio piston is provided, the piston comprising: a piston body arranged inside a cylinder block so as to form a combustion chamber volume; and a compression ratio adjustment rotating body, which is fastened to the piston body so as to vary the combustion chamber volume according to the arrangement state thereof.

Description

Variable compression ratio piston, bi-fuel engine and vehicle including the same

[0001] Embodiments of the present disclosure relate to a variable compression ratio piston, a bi-fuel engine including the same, and a vehicle.

[0002] An internal combustion engine (hereinafter referred to as an engine) is known as a means of generating power by combusting fuel within a cylinder. Today, internal combustion engines are widely used in automobiles, generators, construction equipment, agricultural machinery, and various other industrial equipment.

[0003] Gasoline engines, diesel engines, and other engines feature a combustion chamber where the fuel-air mixture is combusted. The combustion chamber refers to the space formed between the inner cylinder wall and the piston head. The volume and shape of the combustion chamber affect intake and exhaust flow, combustion rate, and other factors, thereby determining engine efficiency and performance.

[0004] One of the key design factors of a combustion chamber is known as the compression ratio. This ratio can be determined by the ratio between the cylinder volume and the combustion chamber volume. The piston reciprocates between top dead center and bottom dead center within the cylinder. Cylinder volume is defined as the volume inside the cylinder when the piston is at bottom dead center, while combustion chamber volume is defined as the volume inside the cylinder when the piston is at top dead center. In other words, the compression ratio can be expressed as the ratio of the maximum volume of the combustion chamber before compression to the minimum volume after compression during the compression stroke.

[0005] Generally, an engine's combustion efficiency and output can increase with a higher compression ratio. However, if the compression ratio is excessively high, serious engine damage can occur due to knocking. Knocking occurs when the fuel-air mixture explodes during compression before the spark plug can properly ignite it. Knocking can cause problems such as damage to pistons, valves, and engine overheating. Accordingly, engines are designed with an ideal compression ratio based on factors such as fuel type. For example, gasoline engines have a compression ratio of approximately 8:1 to 12:1, while diesel engines have a compression ratio of approximately 14:1 to 22:1.

[0006] A typical engine is designed to have a constant compression ratio. In contrast, some types of engines are designed to vary the compression ratio. This allows for improvements in fuel economy, power output, and other aspects of engine performance, as long as the compression ratio remains within a range that does not cause knocking. These types of engines are called variable compression ratio (VCR) engines. A VCR engine can be configured to vary the compression ratio of the mixture depending on operating conditions. For example, under low-load driving conditions, the compression ratio of the mixture can be increased to improve fuel economy, while under high-load driving conditions, the compression ratio of the mixture can be lowered to prevent knocking and increase engine power.

[0007] Conventional variable compression ratio engines use methods such as changing the top dead center height of the piston during the compression stroke or increasing or decreasing the volume of a sub-combustion chamber provided in the cylinder head. For example, Korean Patent No. 10-1500411 (March 3, 2015) proposed a method of adjusting the compression ratio by rotating an eccentric cam provided on a connecting rod. The patent uses an eccentric cam to change the distance between the crank pin and the piston pin, thereby adjusting the compression ratio. As another example, Korean Patent No. 10-2478081 (December 12, 2022) proposed a method of adjusting the compression ratio through the hydraulic flow of engine oil. The patent uses a method of increasing or decreasing the volume of the combustion chamber by moving a sliding member up and down through a hydraulic line.

[0008] The above description is provided to aid in understanding the technical background of the present disclosure. Therefore, the above description should not be construed to limit, restrict, or limit the technical concepts of the present disclosure. Furthermore, the contents described or implied in the above description do not necessarily represent prior art. The above description may include some contents that do not correspond to prior art.

[0009] Embodiments of the present disclosure are directed to providing a variable compression ratio piston, a bi-fuel engine including the same, and a vehicle.

[0010] Additionally, at least some embodiments of the present disclosure seek to provide a variable compression ratio piston capable of changing the compression ratio depending on the type of fuel, and a bi-fuel engine and vehicle including the same.

[0011] Additionally, at least some embodiments of the present disclosure seek to provide a variable compression ratio piston, a bi-fuel engine and a vehicle including the same, which can be used to improve fuel efficiency, power output, etc. in a bi-fuel engine or vehicle.

[0012] Additionally, at least some embodiments of the present disclosure seek to provide a variable compression ratio piston that can be utilized in the modification of a diesel engine or vehicle, and a bi-fuel engine and vehicle including the same.

[0013] However, the technical challenges that the embodiments of the present disclosure seek to address are not necessarily limited to the technical challenges mentioned above. Other technical challenges not mentioned will be readily apparent to those skilled in the art from the detailed description and other descriptions in the specification.

[0014] According to one embodiment of the present disclosure, a variable compression ratio piston may be provided, including a piston body disposed inside a cylinder block to form a combustion chamber volume; and a compression ratio adjusting rotor connected to the piston body to vary the combustion chamber volume depending on the arrangement state.

[0015] According to another embodiment of the present disclosure, a bi-fuel engine may be provided, comprising: a cylinder block having a combustion chamber; a variable compression ratio piston movably connected to the cylinder block in a forward and backward manner; a connecting rod having one end connected to the variable compression ratio piston via a second connecting rod shaft and the other end eccentrically connected to a crank via a first connecting rod shaft; wherein the variable compression ratio piston includes a piston body disposed inside the cylinder block to form a volume of the combustion chamber; and a compression ratio control rotating body connected to the piston body to vary the volume of the combustion chamber depending on a fuel.

[0016] According to another aspect of the present disclosure, a vehicle including the above bi-fuel engine may be provided.

[0017] Embodiments of the present disclosure can provide a variable compression ratio piston, a bi-fuel engine including the same, and a vehicle.

[0018] Additionally, at least some embodiments of the present disclosure include a compression ratio-adjustable rotor, which can vary the compression ratio depending on the fuel type. At least some embodiments of the present disclosure can directly vary the volume of the combustion chamber through the compression ratio-adjustable rotor, and the stroke length of the variable compression ratio piston can be maintained despite the variation in the compression ratio. Accordingly, at least some embodiments of the present disclosure can implement a compression ratio variation depending on the fuel type with relatively little impact on the design of an existing engine. Furthermore, at least some embodiments of the present disclosure can be implemented at relatively low cost.

[0019] Furthermore, at least some embodiments of the present disclosure can improve fuel efficiency, output, etc. in a bi-fuel engine or vehicle by appropriately varying the compression ratio depending on the fuel type. In at least some embodiments of the present disclosure, the degree of compression ratio depending on the fuel type can be appropriately implemented by changing the shape of a compression ratio-adjusting rotor. Accordingly, at least some embodiments of the present disclosure can be easily compatible with bi-fuel engines and the like that use various fuels.

[0020] Additionally, at least some embodiments of the present disclosure can be suitably utilized to replace existing diesel engines in vehicles, construction equipment, agricultural equipment, etc. that use existing diesel engines.

[0021] However, the technical effects that can be achieved through the embodiments of the present disclosure are not necessarily limited to the effects mentioned above. Other technical effects not mentioned will be readily apparent to those skilled in the art to which the present disclosure pertains from other descriptions in the specification, including the detailed description.

[0022] FIG. 1 is a schematic diagram showing a bi-fuel engine according to one embodiment of the present disclosure.

[0023] Figure 2 is a schematic perspective view showing an enlarged view of the variable compression ratio piston and connecting rod illustrated in Figure 1.

[0024] Figure 3 is a perspective view of the variable compression ratio piston and connecting rod shown in Figure 2 viewed from another direction.

[0025] Figure 4 is a schematic longitudinal cross-sectional view of the variable compression ratio piston and connecting rod illustrated in Figure 2.

[0026] Figure 5 is an enlarged view of the variable compression ratio piston illustrated in Figure 4.

[0027] Figure 6 is a drawing showing the appearance of the variable compression ratio piston illustrated in Figure 5 with the rotating body removed.

[0028] Figure 7 is a drawing showing the rotating body illustrated in Figure 5 in isolation.

[0029] Figure 8 is a schematic longitudinal cross-sectional view of the rotating body illustrated in Figure 7.

[0030] Figure 9 is a first operating state diagram of the bi-fuel engine illustrated in Figure 1.

[0031] Figure 10 is a second operating state diagram of the bi-fuel engine illustrated in Figure 1.

[0032] Hereinafter, embodiments of the present disclosure will be described with reference to the attached drawings.

[0033] The following examples are provided to more faithfully and completely explain the technical concepts of the present disclosure to those skilled in the art. Therefore, the technical concepts of the present disclosure are not necessarily limited to the following examples. It should be understood that the present disclosure broadly encompasses various equivalents, alternatives, and variations that implement the technical concepts described below.

[0034] The terminology used in the following description is intended to more faithfully and completely describe specific embodiments from the above perspective. Therefore, the terminology used in the following description should not be construed to limit, restrict, or otherwise limit the technical scope of the present disclosure.

[0035] In the following description, terms such as "first," "second," etc. may be used to distinguish certain components from other components. However, such terms are used for clarity of explanation, and the technical concepts of the present disclosure should not be construed as being limited by such terms.

[0036] In the following description, singular expressions may be interpreted to include the plural unless the context clearly excludes them. Furthermore, the expression "includes" in the following description means the presence of the components, parts, operations, features, steps, numbers, etc. described in the description, and does not exclude the addition of one or more other components, parts, operations, features, steps, numbers, etc.

[0037] In the following description, terms related to direction, such as "beneath," "above," "lower," and "upper," may be used to facilitate understanding of components. However, such terms are provided to facilitate understanding of the present disclosure according to various operations, usage states, etc. of the present disclosure, and should not be construed to reduce, limit, or restrict the technical spirit of the present disclosure. For example, terms related to direction may be determined from a relative perspective.

[0038] Meanwhile, in the drawings below, the size of each component may be exaggerated or omitted for convenience and clarity of explanation.

[0039] FIG. 1 is a schematic diagram showing a bi-fuel engine according to one embodiment of the present disclosure.

[0040] In some embodiments, the bi-fuel engine (100) may be configured to utilize multiple types of fuel. For example, the bi-fuel engine (100) may be configured to utilize heterogeneous fuels including gasoline and Compressed Natural Gas (CNG). In another example, the bi-fuel engine (100) may be configured to utilize heterogeneous fuels including gasoline and Liquefied Natural Gas (LNG). The bi-fuel engine (100) may be configured to utilize heterogeneous fuels of different combinations other than those exemplified above.

[0041] For convenience of explanation, one type of fuel provided to the bi-fuel engine (100) will hereinafter be referred to as "first fuel," and the other type of fuel will be referred to as "second fuel." For example, the first fuel may include compressed natural gas, and the second fuel may include gasoline.

[0042] In some embodiments, the first fuel and the second fuel may be formed to have different ideal compression ratios. Here, the ideal compression ratio may refer to a compression ratio of fuel commonly used in the art, taking into account combustion efficiency, engine knocking, etc. For example, a gasoline engine may typically have a compression ratio of about 8:1 to 12:1, and a compressed natural gas engine may typically have a compression ratio of about 10:1 to 13:0. Here, compressed natural gas has a relatively high octane rating and can be stably combusted without knocking even at a higher compression ratio than gasoline.

[0043] In some embodiments, the bi-fuel engine (100) may include gasoline as one of the heterogeneous fuels. Accordingly, the bi-fuel engine (100) may be implemented following the basic structure of a gasoline engine.

[0044] In some embodiments, the bi-fuel engine (100) may be implemented as a variety of engines that generate power by combusting fuel within a cylinder. For example, the bi-fuel engine (100) may be implemented as a vehicle engine, or as an engine usable in generators, construction equipment, agricultural machinery, and various other industrial equipment.

[0045] In some embodiments, the bi-fuel engine (100) may be applied to replace existing diesel engines in vehicles, construction equipment, agricultural machinery, and the like. In such cases, the existing diesel engine mounted on the vehicle or the like may be removed in part or in whole in an appropriate manner, and the bi-fuel engine (100) according to embodiments of the present disclosure may be newly mounted on the vehicle to replace the existing diesel engine.

[0046] In some embodiments, the bi-fuel engine (100) may be applied to retrofit existing gasoline engines in vehicles, construction equipment, agricultural machinery, and the like. In such cases, the bi-fuel engine (100) may replace the existing gasoline engine by sharing some components with the existing gasoline engine while replacing or modifying other components. Here, the bi-fuel engine (100) according to embodiments of the present disclosure can easily retrofit existing engines at relatively low cost by reducing the replacement or modification of existing components.

[0047] Referring to FIG. 1, in some embodiments, a bi-fuel engine (100) may include a cylinder block (110). The cylinder block (110) may form a combustion chamber (111) into which a mixture of fuel and air is supplied and combusted. The combustion chamber (111) may be arranged inside the cylinder block (110). In some embodiments, a plurality of sets of cylinder blocks (110) may be provided. For example, two, three, four, six, eight, etc. cylinder blocks (110) may be provided. Since each cylinder block (110) may be formed identically or similarly, for convenience, the description will be centered on one cylinder block (110) in this description.

[0048] In some embodiments, the bi-fuel engine (100) may include a cylinder head (120). The cylinder head (120) may be coupled with a cylinder block (110) to form a portion of a combustion chamber (111). In some cases, the cylinder head (120) may be formed integrally with the cylinder block (110) in part or in whole. In the illustrated embodiment, the cylinder head (120) is disposed on top of the cylinder block (110).

[0049] In some embodiments, the cylinder head (120) may have an intake port (121) communicating with the combustion chamber (111). The intake port (121) may be configured to supply a fuel and air mixture to the combustion chamber (111) by being controlled to open and close by an intake valve (121a). In some embodiments, the cylinder head (120) may have an exhaust port (122) communicating with the combustion chamber (111). The exhaust port (122) may be configured to exhaust combustion gas combusted in the combustion chamber (111) by being controlled to open and close by an exhaust valve (122a). In some embodiments, a spark plug (123) may be arranged between the intake port (121) and the exhaust port (122) to provide a spark to the combustion chamber (111).

[0050] In some embodiments, the bi-fuel engine (100) may include a variable compression ratio piston (130). The variable compression ratio piston (130) may be formed to be movable forward and backward within the cylinder block (110). The variable compression ratio piston (130) may move forward (ascend) toward the combustion chamber (111) to compress the mixture, and may move backward (descend) by combustion (explosion) of the mixture within the combustion chamber (111) to provide rotational power to the crank (140). The detailed configuration of the variable compression ratio piston (130) will be described later.

[0051] In some embodiments, the bi-fuel engine (100) may include a crankcase (141). The crankcase (141) may extend downwardly from the cylinder block (110). In some cases, the crankcase (141) may be formed integrally with the cylinder block (110) in part or in whole.

[0052] In some embodiments, a crank (140) may be arranged inside a crankcase (141). The crank (140) may have a crankshaft (S1) and may be rotatably supported on the crankcase (141) about the crankshaft (S1).

[0053] In some embodiments, a connecting rod (150) may be arranged inside the crankcase (141). The connecting rod (150) may be rotatably connected to the crank (140) at one end (lower end) about a first connecting rod shaft (S2). The first connecting rod shaft (S2) may be arranged eccentrically with the crank shaft (S1). In addition, the connecting rod (150) may be rotatably connected to the variable compression ratio piston (130) at the other end (upper end) about a second connecting rod shaft (S3). The connecting rod (150) may be formed to move the variable compression ratio piston (130) forward and backward (up and down) through the first and second connecting rod shafts (S2, S3).

[0054] Fig. 2 is a schematic perspective view showing the variable compression ratio piston and connecting rod illustrated in Fig. 1 in an enlarged manner. Fig. 3 is a perspective view of the variable compression ratio piston and connecting rod illustrated in Fig. 2 viewed from another direction. Fig. 4 is a schematic longitudinal cross-sectional view of the variable compression ratio piston and connecting rod illustrated in Fig. 2.

[0055] Referring to FIGS. 2 to 4, in some embodiments, the variable compression ratio piston (130) may include a piston body (131) and a compression ratio adjusting rotor (132).

[0056] The piston body (131) can form the overall outer shape of the variable compression ratio piston (130). In some embodiments, the plane shape of the piston body (131) can be formed in an approximately circular shape, and the outer side surface (131e) of the piston body (131) can be formed in an approximately cylindrical shape. The piston body (131) is connected to the connecting rod (150) so as to be rotatable about the second connecting rod shaft (S3), and can be moved up and down within the cylinder block (110) according to the operation of the connecting rod (150).

[0057] The compression ratio adjusting rotor (132) may be arranged approximately at the center of the piston body (131) in a plan view. The compression ratio adjusting rotor (132) may be arranged so that at least a portion thereof is exposed to the piston head portion (131a) of the piston body (131). In the illustrated embodiment, the compression ratio adjusting rotor (132) is arranged so as to be exposed to the central region of the outer upper surface of the piston body (131). The compression ratio adjusting rotor (132) may be exposed to the outer upper surface of the piston body (131) to form a portion of the piston head portion (131a). That is, the compression ratio adjusting rotor (132) may be exposed to the piston head portion (131a) at least a portion thereof to contribute to forming the bottom region of the combustion chamber (111).

[0058] In some embodiments, the compression ratio control rotor (132) may be formed to be rotatable a predetermined section around the first connecting rod shaft (S2). The arrangement of the compression ratio control rotor (132) may vary depending on the rotational position around the first connecting rod shaft (S2). For example, in the arrangement as in the illustrated embodiment, the compression ratio control rotor (132) may be rotated a predetermined angle around the first connecting rod shaft (S2), thereby varying the arrangement. In some embodiments, a change in the rotation or arrangement of the compression ratio control rotor (132) may function to change the volume of the combustion chamber (111).

[0059] Meanwhile, in some embodiments, the connecting rod (150) may be provided with an operating portion (160). The operating portion (160) may be formed to vary the arrangement state of the compression ratio adjusting rotor (132). In some embodiments, the operating portion (160) may include a first operating portion (161) and a second operating portion (162). The first operating portion (161) may function to rotate the compression ratio adjusting rotor (132) to a first arrangement state, and the second operating portion (162) may function to rotate the compression ratio adjusting rotor (132) to a second arrangement state. In some embodiments, the first and second operating portions (161, 162) may be implemented in a form installed internally on one side of the connecting rod (150). In the illustrated embodiment, the first and second operating parts (161, 162) are arranged on the left and right sides of the connecting rod (150).

[0060] Specifically, the first operating part (161) may have a first conversion rod (161a). The first conversion rod (161a) may have a bar shape extending in the longitudinal direction. One end (upper end) of the first conversion rod (161a) may be connected to the compression ratio adjusting rotor (132) via the first upper link (161b). The first upper link (161b) may provide a transverse rotation axis, and the first conversion rod (161a) may be formed to be rotatable about the first upper link (161b). The other end (lower end) of the first conversion rod (161a) may be connected to the first movable cap (161d) via the first lower link (161c). The first lower link (161c) can provide a transverse rotation axis, and the first conversion rod (161a) can be formed to be rotatable around the first lower link (161c).

[0061] The first movable cap (161d) may be arranged in the first conversion cylinder (161e). The first conversion cylinder (161e) may be provided with a first movable chamber (not indicated) (see the second movable chamber (162g)), and the first movable cap (161d) may be arranged to be accommodated in the first movable chamber. The first movable chamber may be formed to extend in the operating direction of the first movable cap (161d) so that the first movable cap (161d) can move with a predetermined operating distance. In the illustrated embodiment, the first movable chamber extends obliquely at a predetermined angle with respect to the vertical direction.

[0062] The first movable chamber may be connected to a first movable passage (161f). The first movable passage (161f) may supply or discharge working fluid to or from the first movable chamber. Accordingly, the first movable cap (161d) disposed in the first movable chamber may be moved up and down within the first movable chamber. In some embodiments, the first movable passage (161f) may be formed to extend into the interior of the connecting rod (150). In addition, although not shown, a hydraulic line or the like for supplying or discharging working fluid may be connected to an end of the first movable passage (161f).

[0063] The second operating part (162) can be formed generally similarly to the first operating part (161). The second operating part (162) can be provided with a second conversion rod (162a), and one end (upper end) of the second conversion rod (162a) can be connected to the compression ratio adjusting rotor (132) via a second upper link (162b). The other end (lower end) of the second conversion rod (162a) can be connected to a second movable cap (162d) via a second lower link (162c). The second movable cap (162d) can be arranged in a second conversion cylinder (162e), and the second conversion cylinder (162e) can be provided with a second movable chamber (162g). The second movable cap (162d) may be arranged to be accommodated in the second movable chamber (162g). The second movable chamber (162g) may be connected to the second movable flow path (162f), and the second movable flow path (162f) may supply or discharge working fluid to or from the second movable chamber (162g).

[0064] In some embodiments, the first and second operating parts (161, 162) may be positioned at different positions with respect to the longitudinal direction of the connecting rod (150). For example, the first operating part (161) may be positioned at a relatively low position with respect to the longitudinal direction of the connecting rod (150), and the second operating part (162) may be positioned at a relatively high position with respect to the longitudinal direction of the connecting rod (150). Furthermore, in some embodiments, the first and second operating parts (161, 162) may be operated in an inclined direction while forming a predetermined angle with respect to the vertical direction. Such positions and operating directions of the first and second operating parts (161, 162) may contribute to effective transmission of operating force to the compression ratio adjusting rotor (132). Additionally, despite the addition of the first and second operating parts (161, 162), the connecting rod (150) can maintain a compact structure and shape.

[0065] Fig. 5 is an enlarged view of the variable compression ratio piston illustrated in Fig. 4. Fig. 6 is a drawing showing the variable compression ratio piston illustrated in Fig. 5 with the rotor removed. Fig. 7 is a drawing showing the rotor illustrated in Fig. 5 in isolation. Fig. 8 is a schematic longitudinal cross-sectional view of the rotor illustrated in Fig. 7.

[0066] Referring to FIGS. 5 to 8, in some embodiments, the piston body (131) may have a piston head portion (131a). The piston head portion (131a) may be formed as an upper surface area of ​​the piston body (131). In some embodiments, the piston head portion (131a) may be formed in a shape in which the upper surface of the piston body (131) is concave to a certain degree.

[0067] In some embodiments, a head opening (131b) may be formed in the center of the upper surface of the piston body (131). The head opening (131b) may be formed penetratingly in the center of the upper surface of the piston body (131). In some embodiments, the head opening (131b) may be formed in a circular shape on a plane. The circular head opening (131b) may have the advantage of facilitating the shape design or sealing of the compression ratio adjusting rotor (132) in relation to the compression ratio adjusting rotor (132).

[0068] In some embodiments, the head opening (131b) may have a radius (R2) of a predetermined ratio relative to the overall radius (R1) of the piston body (131). For example, the head opening (131b) may have a radius (R2) of 30% to 70% relative to the overall radius (R1) of the piston body (131). If the radius (R2) of the head opening (131b) is excessively small, such as less than or equal to the exemplified 30%, the range of volume change through the compression ratio control rotor (132) may be excessively small, and conversely, if the radius (R2) of the head opening (131b) is excessively large, such as more than or equal to the exemplified 70%, it may be detrimental to the proper arrangement of the compression ratio control rotor (132) or to securing the rigidity of the piston body (131).

[0069] Meanwhile, in some embodiments, the piston body (131) may be provided with a piston skirt (131c). The piston skirt (131c) may extend downward from the piston head portion (131a) to form a side of the piston body (131). The piston skirt (131c) may have an inner side surface (131d) arranged toward the compression ratio adjusting rotor (132) and an outer side surface (131e) corresponding to the inner side surface (131d). The outer side surface (131e) of the piston skirt (131c) may form a substantially cylindrical outer surface. The inner side surface (131d) of the piston skirt (131c) may be formed such that a portion of the upper portion comes into contact with the outer surface of the compression ratio adjusting rotor (132). The area where the inner side (131d) of the piston skirt (131c) and the outer surface of the compression ratio adjusting rotor (132) come into contact can form a closed shape in a plan view. For example, the above-mentioned contact area can form an approximately circular ring shape in a plan view. The contact area forming the closed shape can function as a sealing area that seals the space between the head opening (131b) and the compression ratio adjusting rotor (132).

[0070] In some embodiments, a second sealing groove (131f) may be formed in the above contact area. The second sealing groove (131f) may be positioned adjacent to the upper portion of the inner side surface (131d) of the piston body (131). In addition, the second sealing groove (131f) may be extended to have a closed shape in a plan view. For example, the second sealing groove (131f) may be extended to have a circular ring shape in a plan view. A sealing member may be fastened to the second sealing groove (131f), and the sealing member may function to seal between the head opening (131b) and the compression ratio adjusting rotor (132).

[0071] In some embodiments, a rotation guide surface (131g) may be provided on the inner side surface (131d) of the piston body (131). The rotation guide surface (131g) may be formed as a portion of the upper portion of the inner side surface (131d) adjacent to the head opening (131b). The rotation guide surface (131g) may be formed as a partially spherical surface having a predetermined curvature. In some embodiments, the curvature of the rotation guide surface (131g) may be formed to correspond to the first operating surface (132b) of the compression ratio adjusting rotor (132). That is, the rotation guide surface (131g) may be formed to have a curvature corresponding to the first operating surface (132b). Such a rotation guide surface (131g) may contribute to improving sealing performance by securing an appropriate contact area with the compression ratio adjusting rotor (132). In addition, such a rotation guide surface (131g) can function to guide the appropriate rotational motion of the compression ratio-adjusting rotation body (132).

[0072] In some embodiments, a first sealing groove (131i) may be provided on the outer side surface (131e) of the piston body (131). The first sealing groove (131i) may be formed to extend circumferentially along the outer side surface (131e) of the piston body (131). A sealing member may be fastened to the first sealing groove (131i), and the sealing member may function to seal between the piston body (131) and the cylinder block (110).

[0073] In some embodiments, the piston body (131) may include a piston pin (131h). The piston pin (131h) may provide a first connecting rod shaft (S2). The piston pin (131h) may extend laterally between the two inner side surfaces (131d) of the piston skirt (131c).

[0074] Meanwhile, in some embodiments, the compression ratio adjusting rotor (132) may be rotatably connected to the piston body (131) at a predetermined angle. The compression ratio adjusting rotor (132) may be provided with a pin fastening hole (132a) that laterally penetrates the compression ratio adjusting rotor (132), and the pin fastening hole (132a) may be connected to a piston pin (131h) provided in the piston body (131). Accordingly, the compression ratio adjusting rotor (132) may be formed to be rotatably connected to a predetermined angle about the piston pin (131h) or the second connecting rod shaft (S3).

[0075] In some embodiments, a first upper link (161b) may be fastened to one side (lower left) of the compression ratio control rotor (132), and a second upper link (162b) may be fastened to the other side (upper right). The compression ratio control rotor (132) may receive operating power from the first and second operating units (161, 162) through the first and second upper links (161b, 162b).

[0076] In some embodiments, the compression ratio control rotor (132) may have a first operating surface (132b). In the illustrated embodiment, the first operating surface (132b) is illustrated as an upper surface area of ​​the compression ratio control rotor (132). The first operating surface (132b) may be selectively coupled to the head opening (131b) depending on the arrangement of the compression ratio control rotor (132). That is, the first operating surface (132b) may be coupled to the head opening (131b) or detached from the head opening (131b) depending on the arrangement of the compression ratio control rotor (132).

[0077] In some embodiments, the first operating surface (132b) may have a convexly protruding curved shape. The protruding first operating surface (132b) may be compared with the second operating surface (132c) described later. The protruding first operating surface (132b) may function to reduce the volume of the combustion chamber (111) by a corresponding volume. That is, the first operating surface (132b) may be arranged so that at least a portion thereof protrudes into the combustion chamber (111) through the head opening (131b), thereby functioning to relatively reduce the volume of the combustion chamber (111).

[0078] In some embodiments, the first operating surface (132b) may be formed as a partially spherical surface having a predetermined curvature. In addition, the curvature of the first operating surface (132b) may be formed to correspond to the curvature of the rotational guide surface (131g) of the piston body (131). That is, the first operating surface (132b) may be formed to have a curvature corresponding to the rotational guide surface (131g). As described above, such a first operating surface (132b) may have functions such as improving sealing performance and guiding rotational motion.

[0079] In some embodiments, the first operating surface (132b) may be formed to have a substantially circular shape in a plan view, and the circular first operating surface (132b) may have a predetermined radius (R3) in a plan view. The radius (R3) of the first operating surface (132b) may be formed to be a predetermined degree smaller than the overall radius (R1) of the piston body (131), but may be formed to be a predetermined degree larger than the radius (R2) of the head opening (131b). For example, the radius (R3) of the first operating surface (132b) may be formed to be 5% to 10% larger than the radius (R2) of the head opening (131b). This allows for securing an appropriate sealing area between the first operating surface (132b) and the head opening (131b).

[0080] Meanwhile, in some embodiments, the compression ratio control rotor (132) may have a second operating surface (132c). In the illustrated embodiment, the second operating surface (132c) is illustrated as a side region of the compression ratio control rotor (132). Similar to the first operating surface (132b) described above, the second operating surface (132c) may be selectively coupled to the head opening (131b) depending on the arrangement of the compression ratio control rotor (132). That is, the second operating surface (132c) may be coupled to the head opening (131b) or detached from the head opening (131b) depending on the arrangement of the compression ratio control rotor (132). For reference, FIG. 5 illustrates a state in which the first operating surface (132b) is coupled to the head opening (131b) and the second operating surface (132c) is separated from the head opening (131b).

[0081] In some embodiments, the second operating surface (132c) may have a gently curved shape compared to the first operating surface (132b). Alternatively, the second operating surface (132c) may be formed to be close to a planar shape compared to the first operating surface (132b). In the illustrated embodiment, the second operating surface (132c) is illustrated as having a shape that is approximately close to a planar shape. The second operating surface (132c) may function to increase the volume of the combustion chamber (111) to a predetermined degree compared to the first operating surface (132b). That is, the second operating surface (132c) may be formed to protrude less into the combustion chamber (111) compared to the first operating surface (132b), thereby functioning to relatively increase the volume of the combustion chamber (111).

[0082] In some embodiments, the second operating surface (132c) may be formed to have a substantially circular shape in plan view. That is, in the illustrated embodiment, the second operating surface (132c) may have a substantially circular shape when viewed from the side. In addition, the circular second operating surface (132c) may have a predetermined radius (R4). The radius (R4) of the second operating surface (132c) may be formed to be a predetermined amount smaller than the overall radius (R1) of the piston body (131), but may be formed to be a predetermined amount larger than the radius (R2) of the head opening (131b). For example, the radius (R4) of the second operating surface (132c) may be formed to be 5% to 10% larger than the radius (R2) of the head opening (131b). This is similar to the first operating surface (132b) described above.

[0083] Figure 9 is a first operating state diagram of the bi-fuel engine illustrated in Figure 1.

[0084] Referring to FIG. 9, in some operating examples, the bi-fuel engine (100) may be driven by a first fuel. For example, the first fuel may include compressed natural gas. When the first fuel is supplied, the compression ratio control rotor (132) may be arranged such that the first operating surface (132b) is connected to the head opening (131b). The operating unit (160) may be arranged such that the first conversion rod (161a) is arranged at the bottom dead center and the second conversion rod (162a) is arranged at the top dead center, thereby arranging the compression ratio control rotor (132) as described above.

[0085] The compression ratio control rotor (132) can be arranged so that the first operating surface (132b) is exposed to the combustion chamber (111), and accordingly, the volume of the combustion chamber (111) can be determined. That is, the volume according to the shape of the first operating surface (132b) can be reflected to create the volume of the combustion chamber (111). The shape of the first operating surface (132b) can be appropriately designed in consideration of the ideal compression ratio of the first fuel. For example, the outer shape, area, protrusion, etc. of the first operating surface (132b) can be designed in consideration of the ideal compression ratio of compressed natural gas. Accordingly, the bi-fuel engine (100) can proceed with an engine cycle with a combustion chamber (111) volume optimized for the first fuel.

[0086] Figure 10 is a second operating state diagram of the bi-fuel engine illustrated in Figure 1.

[0087] Referring to FIG. 10, in some operating examples, the bi-fuel engine (100) may be driven by a second fuel. The second fuel may be a different fuel than the first fuel, for example, the second fuel may include gasoline. When the second fuel is supplied, the compression ratio control rotor (132) may be arranged so that the second operating surface (132c) is engaged with the head opening (131b). The operating unit (160) may be arranged so that the first conversion rod (161a) is arranged at the top dead center and the first conversion rod (161a) is arranged at the bottom dead center, thereby arranging the compression ratio control rotor (132) as described above.

[0088] Similar to the case of the first operating surface (132b) described above, the compression ratio control rotor (132) can be arranged so that the second operating surface (132c) is exposed to the combustion chamber (111), and accordingly, the volume of the combustion chamber (111) can be determined. That is, the volume according to the shape of the second operating surface (132c) can be reflected to create the volume of the combustion chamber (111). The shape of the second operating surface (132c) can be appropriately designed in consideration of the ideal compression ratio of the second fuel. For example, the outer shape, area, protrusion, etc. of the second operating surface (132c) can be designed in consideration of the ideal compression ratio of gasoline. Accordingly, the bi-fuel engine (100) can proceed with an engine cycle with a combustion chamber (111) volume optimized for the second fuel.

[0089] As described above, embodiments of the present disclosure can provide a variable compression ratio piston, a bi-fuel engine including the same, and a vehicle.

[0090] Additionally, at least some embodiments of the present disclosure include a compression ratio-adjustable rotor, which can vary the compression ratio depending on the fuel type. At least some embodiments of the present disclosure can directly vary the volume of the combustion chamber through the compression ratio-adjustable rotor, and the stroke length of the variable compression ratio piston can be maintained despite the variation in the compression ratio. Accordingly, at least some embodiments of the present disclosure can implement a compression ratio variation depending on the fuel type with relatively little impact on the design of an existing engine. Furthermore, at least some embodiments of the present disclosure can be implemented at relatively low cost.

[0091] Furthermore, at least some embodiments of the present disclosure can improve fuel efficiency, output, etc. in a bi-fuel engine or vehicle by appropriately varying the compression ratio depending on the fuel type. In at least some embodiments of the present disclosure, the degree of compression ratio depending on the fuel type can be appropriately implemented by changing the shape of a compression ratio-adjusting rotor. Accordingly, at least some embodiments of the present disclosure can be easily compatible with bi-fuel engines and the like that use various fuels.

[0092] Additionally, at least some embodiments of the present disclosure can be suitably utilized to replace existing diesel engines in vehicles, construction equipment, agricultural equipment, etc. that use existing diesel engines.

[0093] Although the embodiments of the present disclosure have been described above, a person having ordinary skill in the art will be able to modify or change the present disclosure in various ways by adding, changing, deleting or adding components, etc., within the scope that does not depart from the technical idea of ​​the present disclosure described in the claims, and this will also be considered to be included in the scope of the rights of the present disclosure.

Claims

1. A piston body arranged inside the cylinder block to form a combustion chamber volume; and A variable compression ratio piston, comprising a compression ratio adjusting rotor that is connected to the piston body and varies the volume of the combustion chamber depending on the arrangement state.

2. In claim 1, The above piston body is a variable compression ratio piston having a head opening formed through the upper surface area forming the combustion chamber volume.

3. In claim 2, The above head opening is a variable compression ratio piston formed in a circular shape having a predetermined radius on a plane.

4. In claim 3, A variable compression ratio piston, wherein the radius of the head opening is formed to be a predetermined amount smaller than the radius of the first operating surface of the compression ratio adjusting rotor or the radius of the second operating surface of the compression ratio adjusting rotor.

5. In claim 1, The above piston body includes a piston skirt forming a side of the piston body, The above piston skirt, An outer side disposed toward the inner surface of the cylinder block; and Including an inner side corresponding to the outer side, A variable compression ratio piston, wherein the inner side includes a contact area in contact with the outer surface of the compression ratio adjusting rotor.

6. In claim 5, The above contact area is a variable compression ratio piston formed in the form of a closed shape including a circular ring on a plane.

7. In claim 5, A variable compression ratio piston, wherein the inner side surface is provided with a second sealing groove formed in the shape of a closed shape including a circular ring on a plane, and is disposed at the upper end of the contact area.

8. In claim 5, The inner side surface has a rotation guide surface in an upper portion including the contact area, A variable compression ratio piston, wherein the above-mentioned rotating body guide surface is formed as a partially spherical surface having a predetermined curvature.

9. In claim 8, A variable compression ratio piston, wherein the above-mentioned rotating body guide surface is formed to have a curvature corresponding to a portion of the outer surface of the compression ratio-adjusting rotating body.

10. In claim 1, The above compression ratio adjusting rotor is, A first operating surface coupled to the head opening of the piston body to form a predetermined combustion chamber volume; and A variable compression ratio piston comprising a second operating surface selectively coupled to the head opening for the first operating surface to form a predetermined combustion chamber volume.

11. In claim 10, A variable compression ratio piston, wherein the combustion chamber volume formed by the first operating surface is formed differently from the combustion chamber volume formed by the second operating surface.

12. In claim 10, The above first operating surface is formed as a partially spherical surface protruding with a predetermined curvature, A variable compression ratio piston, wherein the second operating surface is formed in a gently curved shape or a flat shape compared to the first operating surface.

13. In claim 12, A variable compression ratio piston, wherein the curvature of the first operating surface is formed to correspond to a portion of the inner side surface of the piston body.

14. Cylinder block having a combustion chamber; A variable compression ratio piston that is connected to the cylinder block so as to be able to move forward and backward; A connecting rod having one end connected to the variable compression ratio piston through a second connecting rod shaft and the other end eccentrically connected to the crank through a first connecting rod shaft, The above variable compression ratio piston is, A piston body arranged inside the cylinder block to form the volume of the combustion chamber; and A bi-fuel engine comprising a compression ratio-adjusting rotating body connected to the piston body and configured to vary the volume of the combustion chamber depending on the fuel.

15. In claim 14, A bi-fuel engine further comprising a movable part that changes the arrangement state of the compression ratio adjusting rotor.

16. In claim 15, The above movable part, A first operating unit that is connected to one side of the compression ratio adjusting rotor and rotates the compression ratio adjusting rotor in one direction; and A bi-fuel engine, comprising a second operating unit that is connected to the other side of the compression ratio adjusting rotor and rotates the compression ratio adjusting rotor in the opposite direction to the one side.

17. In claim 16, The above first operating unit is, A first conversion rod, one end of which is rotatably connected to the compression ratio adjusting rotor through the first upper link, and the other end of which is rotatably connected to the first movable cap through the first lower link; A first conversion cylinder forming a first movable chamber in which the first movable cap moves up and down; and A bi-fuel engine comprising a first operating passage for supplying or discharging operating fluid to the first operating chamber.

18. In claim 16, A bi-fuel engine in which the first and second operating parts are arranged on the connecting rod, but are arranged at different positions with respect to the longitudinal direction of the connecting rod, form a predetermined angle with respect to the up-down direction, and are formed to operate in an inclined direction.

19. A vehicle comprising the bi-fuel engine of claim 14.

Images