A cylinder liner for an opposed-piston two-stroke engine with a variable airflow organization

Abstract

The present invention relates to the technical field of opposed two-stroke engines, and discloses a cylinder liner for an opposed-piston two-stroke engine with a variable airflow organization form. The liner comprises a main cylinder liner and an intake-end cylinder liner that are mutually sleeved and connected. The main cylinder liner comprises a mating end near the intake port and a fixed end near the exhaust port. The sidewall of the mating end near the intake port is provided with a plurality of inner intake ports, and the sidewall of the fixed end near the exhaust port is provided with a plurality of exhaust ports. The intake-end cylinder liner comprises an extended fixed end and a mating end. The mating end of the intake-end cylinder liner has n layers of external intake ports of different configurations distributed axially, where n is greater than or equal to 2. The internal intake ports correspond to the external intake ports of different configurations, thereby changing the airflow organization form of the cylinder liner. The present invention can change the intake angle, solving the problem of a single airflow organization form within the cylinder and difficulty in making appropriate adjustments based on actual conditions.

Description

Technical Field

[0001] The present invention relates to the technical field of opposed two-stroke engines, and more particularly to a cylinder liner of an opposed-piston two-stroke engine with a variable airflow organization form. Background Art

[0002] The cylinder of an opposed-piston two-stroke engine is enclosed by two opposing pistons, offering advantages such as low specific mass, simple structure, high power, and high torque. Furthermore, the lack of a cylinder head reduces heat and friction losses, giving opposed-piston two-stroke engines high thermal efficiency. Furthermore, the opposed piston layout results in relatively low vibration. Compared to compression-ignition engines, spark-ignition engines offer lower mass, lower cost, and gentler operation, making them particularly suitable for land transportation and other applications.

[0003] Opposed-piston two-stroke engines do not have a separate ventilation stroke. Instead, they rely on the reciprocating motion of the piston to open or close the intake and exhaust ports to complete the ventilation process. Since the ventilation period is very short and the intake and exhaust processes occur simultaneously, fresh charge and exhaust gas will mix, resulting in a large residual exhaust gas coefficient in the cylinder and poor scavenging quality. Opposed-piston two-stroke engines have several scavenging ports and exhaust ports opened around the cylinder liner at both ends, and most of them use direct current scavenging. During the upward stroke of the intake piston and the downward stroke of the exhaust piston, the exhaust port is often opened first for natural exhaust. As the intake piston continues to rise, the intake port opens. This moment is the scavenging timing, and fresh air enters the cylinder for scavenging and ventilation processes. As the intake piston continues to rise, the area of the scavenging port opening gradually increases until the piston fully opens the scavenging port, reaches the intake piston top dead center, and descends, gradually closing the intake port.

[0004] Therefore, the ventilation process is crucial for opposed-piston two-stroke engines, determining the quality of fresh air entering the cylinder and, in turn, influencing the entire engine cycle. This process is both a key and challenging area of two-stroke engine research. Well-organized in-cylinder gas flow plays a crucial role in discharging exhaust gases and improving combustion efficiency. In traditional cylinder liners, the intake port dimensions are fixed, resulting in an unchangeable intake angle. This results in a single flow pattern within the cylinder, making it difficult to tailor the flow to meet specific engine power, fuel efficiency, and emissions requirements. Summary of the Invention

[0005] In view of this, the present invention provides an opposed-piston two-stroke engine cylinder liner with a variable airflow organization form, which can change the intake angle and solve the problem that the airflow organization form in the cylinder is single and difficult to make appropriate adjustments according to actual conditions.

[0006] To achieve the above-mentioned objectives, the present invention provides an opposed-piston two-stroke engine cylinder liner with a variable airflow organization form, comprising a main cylinder liner and an intake-end cylinder liner which are sleeved and connected to each other, the main cylinder liner comprising a fitting end near the intake port and a fixed end near the exhaust port, a plurality of inner intake ports are arranged on the side wall of the fitting end near the intake port, a plurality of exhaust ports are arranged on the side wall of the fixed end near the exhaust port, the intake-end cylinder liner comprises an extended fixed end and a fitting end, and n layers of outer intake ports of different configurations are distributed axially on the fitting end of the intake-end cylinder liner, wherein n ≥ 2, and the inner intake ports correspond to the outer intake ports of different configurations respectively to change the airflow organization form in the cylinder liner.

[0007] Preferably, the outer wall of the mating end near the air inlet is uniformly provided with a plurality of axial flat key grooves along the circumferential direction, and the inner wall of the mating end is uniformly provided with a plurality of axial flat keys along the circumferential direction, and the flat keys are adapted to the flat key grooves.

[0008] Preferably, the n layers of outer air inlets on the engaging end are at least two of the following: a basic air inlet, a high swirl ratio air inlet and a high tumble ratio scavenging air inlet.

[0009] Preferably, it also includes an electric control device, which is connected to the extended fixed end of the cylinder liner at the intake end. The electric control device drives the cylinder liner at the intake end to move axially, so that the positions of the external air inlets of different configurations correspond to the positions of the internal air inlets on the main cylinder liner.

[0010] Preferably, the power control device includes a linear stepper motor, a driver and a controller. The linear stepper motor is connected to the extended fixed end of the cylinder sleeve at the intake end. The controller is electrically connected to the driver to convert user instructions into pulse signals and transmit them to the driver. The driver is electrically connected to the linear stepper motor to convert pulse signals into angular displacements and transmit them to the linear stepper motor.

[0011] Preferably, there are two linear stepper motors, and the two linear stepper motors are symmetrically placed and connected at the extended fixed end of the cylinder sleeve at the air intake end with the diameter as the symmetry axis.

[0012] Preferably, the two linear stepper motors are respectively connected to a first displacement sensor and a second displacement sensor, and the first displacement sensor and the second displacement sensor are used to respectively detect the displacement of the two linear stepper motors so that the displacements of the two linear stepper motors are the same.

[0013] Preferably, the linear stepper motor, driver, and controller are all electrically connected to a DC power supply.

[0014] It can be seen from the above technical solutions that, compared with the prior art, the opposed-piston two-stroke engine cylinder liner with a variable airflow organization provided by the present invention has the following beneficial effects:

[0015] (1) The structure of the main cylinder liner and the intake end cylinder liner divides the opposed piston two-stroke engine cylinder liner into two parts. The interlocking structure can match the inner air inlet with the different outer air inlet by the relative upward and downward movement of the main cylinder liner and the intake end cylinder liner, thereby changing the airflow organization form in the cylinder;

[0016] (2) The flat key and flat keyway structure facilitates the engagement between the main cylinder liner and the intake end cylinder liner, restricts the circumferential rotation of the intake end cylinder liner, and achieves relatively stable axial translation between the two parts of the cylinder liner;

[0017] (3) The electric control device is set up to drive the cylinder liner at the intake end to move up and down to adjust the matching of different external intake ports with the internal intake ports, thereby changing the intake angle, so that the airflow organization form in the cylinder can be appropriately adjusted according to the actual working conditions, so that the engine can achieve the required power, economy and emission performance;

[0018] (4) Setting of displacement sensors, controlling the displacement of each linear stepper motor according to the displacement sensor, ensuring accurate matching of the inner and outer air inlets and synchronous operation of each linear stepper motor;

[0019] (5) The controller and driver are set up to send control signals according to user instructions, convert and transmit signals, change the matching of internal and external air inlets according to needs, and thus change the airflow organization form in the cylinder. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0021] Figure 1 A schematic diagram of the assembly structure of the cylinder liner of an opposed-piston two-stroke engine with a variable airflow organization according to the present invention;

[0022] Figure 2 A schematic diagram of the exploded structure of the cylinder liner of an opposed-piston two-stroke engine with a variable airflow organization according to the present invention;

[0023] Figure 3 A schematic diagram of the gas port coordination of the cylinder liner of an opposed-piston two-stroke engine with a variable airflow organization according to the present invention;

[0024] Figure 4 For the present invention Figure 3 Look at the structural diagram;

[0025] Figure 5 For the present invention Figure 4 Schematic diagram of the cross-sectional structure of the EE section;

[0026] Figure 6 For the present invention Figure 5 Schematic diagram of the cross-sectional structure of the cylinder liner at the intake end of the middle DD section;

[0027] Figure 7 This is a schematic diagram of the working principle of the electric control device in the cylinder liner of an opposed-piston two-stroke engine with a variable airflow organization form of the present invention.

[0028] Explanation of reference numerals: 1-main cylinder sleeve; 11-fixed end near exhaust port; 12-fitting end near intake port; 13-flat keyway; 14-inner intake port; 15-exhaust port;

[0029] 2-intake end cylinder liner; 21-extended fixed end; 22-fitting end; 23-flat key; 24-basic intake port; 25-high swirl ratio intake port; 26-high tumble ratio scavenging port;

[0030] 3-power control device; 31-linear stepping motor; 32-DC power supply; 33-driver; 34-controller; 331-first displacement sensor; 332-second displacement sensor. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of an exemplary embodiment is actually only illustrative and is in no way intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0032] Please see the attached Figure 1-7 , which is an opposed-piston two-stroke engine cylinder liner with a variable airflow organization form disclosed in the present invention.

[0033] As shown in the figure, the opposed-piston two-stroke engine cylinder liner with a variable airflow organization form provided by the present invention includes a main cylinder liner 1, an intake end cylinder liner 2 and an electric control device 3, and the main cylinder liner 1 and the intake end cylinder liner 2 are connected to each other.

[0034] like Figure 2As shown, the main cylinder sleeve 1 includes a fixed end 12 near the exhaust port and a mating end 11 near the air inlet port, a plurality of inner air inlets 14 are provided on the mating end 11 near the air inlet port, and the plurality of inner air inlets 14 are circumferentially arranged along the side wall of the mating end 11 near the air inlet port, a plurality of axial flat key grooves 13 are provided on the outer wall of the mating end 11 near the air inlet port, and the plurality of flat key grooves 13 are evenly distributed along the circumference of the mating end 11 near the air inlet port, and preferably there are 4 flat key grooves 13; a plurality of exhaust ports 15 are provided on the fixed end 12 near the exhaust port, and the plurality of exhaust ports 15 are circumferentially arranged along the side wall of the fixed end 12 near the exhaust port.

[0035] It should be noted that the air inlet height h, air inlet width w, air inlet inclination angle α and air inlet elevation angle β of the inner air inlet 14 are all basic design values, and the air inlet inclination angle α and air inlet elevation angle β can be set according to working conditions.

[0036] The intake end cylinder liner 2 includes an extended fixed end 21 and a fitting end 22. The inner wall of the fitting end 22 is provided with a plurality of axial flat keys 23. The plurality of flat keys 23 are evenly arranged along the circumference of the inner wall of the fitting end 22 and are adapted to the flat key grooves 13. Preferably, there are also 4 flat keys 23. The positions of the flat keys 23 and the flat key grooves 13 correspond to each other and are used for matching assembly. The cooperation between the flat keys 23 and the flat key grooves 13 is beneficial to the fitting of the main cylinder liner 1 and the intake end cylinder liner 2, limits the circumferential rotation between the two, and provides guidance for axial translation.

[0037] The fitting end 22 of the cylinder sleeve 2 at the air intake end is distributed with n (n≥2) layers of external air intake ports of different configurations, and the n layers of external air intake ports of different configurations are arranged equidistantly along the axial direction of the fitting end 22, such as Figure 2-3 As shown, the n layers of external air intakes of different configurations include but are not limited to basic air intakes 24 , high swirl ratio air intakes 25 and high tumble ratio scavenging air intakes 26 .

[0038] like Figure 4-6 As shown, the outer air inlets of different configurations correspond to the inner air inlet 14 respectively, so as to change the air flow organization form of the cylinder liner.

[0039] Specifically, when the basic air intake port 24 is matched with the inner air intake port 14, the air flow organization form in the cylinder can meet the emission and economy requirements under rated operating conditions; when the high swirl ratio air intake port 25 is matched with the inner air intake port 14, the swirl structure in the air flow organization form in the cylinder is enhanced, which can appropriately improve the thermal efficiency and further improve the economy; when the high tumble ratio air intake port 26 is matched with the inner air intake port 14, the tumble structure in the air flow organization form in the cylinder is enhanced, which promotes the mixing of fuel and fresh air, improves combustion efficiency, and improves working stability under low load conditions.

[0040] like Figure 7As shown, the electric control device 3 is connected to the extended fixed end 21 of the intake end cylinder liner 2, driving the intake end cylinder liner 2 to move axially so that different external air ports can coincide with the internal air port 14 on the main cylinder liner 1.

[0041] Specifically, the power control device 3 includes: a linear stepper motor 31, a DC power supply 32, a driver 33, a controller 34, a first displacement sensor 331 and a second displacement sensor 332. There are m (m>1) linear stepper motors 31, and the m linear stepper motors 31 are fixedly connected to the extended fixed end 21 of the intake end cylinder liner 2. The extended fixed end 21 is extended along the length of the basic intake end cylinder liner 2 to connect to the linear stepper motor 31. The m linear stepper motors 31 are evenly distributed in the circumferential direction of the intake end cylinder liner 2.

[0042] In this embodiment, there are two linear stepper motors 31, which are respectively connected to the extended fixed end 21 of the cylinder sleeve 2 at the air intake end. The two linear stepper motors 31 are symmetrically placed and connected at the extended fixed end 21 of the cylinder sleeve 2 at the air intake end with the diameter as the symmetry axis; the linear stepper motor 31, the driver 33, and the controller 34 are all electrically connected to the DC power supply 32, and the DC power supply 32 provides energy for the power control device 3; the controller 33 is electrically connected to the driver 34, converting the user's instructions into pulse signals and transmitting them to the driver 34; the driver 34 is electrically connected to the linear stepper motor 31, converting the pulse signals into angular displacements and transmitting them to the linear stepper motor 31; the first displacement sensor 331 and the second displacement sensor 332 are connected to the linear stepper motor 31 to detect the displacement of each linear stepper motor 31 to ensure that the displacement of each linear stepper motor 31 is the same.

[0043] The embodiments of the present disclosure have been described in detail with reference to the accompanying drawings. It should be noted that any implementations not depicted or described in the drawings or the main text of the specification are known to those skilled in the art and are not described in detail. Furthermore, the above definitions of the various elements and methods are not limited to the various specific structures, shapes, or methods described in the embodiments, and can be easily modified or replaced by those skilled in the art.

[0044] To sum up, the opposed-piston two-stroke engine cylinder liner with a variable airflow organization form provided by the present invention divides the existing opposed-piston two-stroke engine cylinder liner into two parts at the intake end, namely the main cylinder liner 1 and the intake end cylinder liner 2, which are engaged with each other through the flat key 23 and the flat key groove 13 structure, and the intake end cylinder liner 2 is driven up and down by the electric control device 3, so that the selection of air ports with different structural designs can adapt to actual working conditions, so that the engine can achieve the required power, economy and emission performance.

[0045] It should also be noted that directional terms such as "upper," "lower," "front," "back," "left," and "right" mentioned in the embodiments are merely references to the directions in the accompanying drawings and are not intended to limit the scope of protection of this disclosure. Throughout the drawings, identical elements are represented by identical or similar reference numerals. Conventional structures or configurations will be omitted where they may cause confusion in understanding this disclosure.

[0046] Furthermore, the shapes and sizes of the components in the figures do not reflect the actual sizes and proportions, but are merely illustrative of the contents of the embodiments of the present disclosure. In addition, in the claims, any reference signs placed between brackets should not be construed as limiting the claims.

[0047] Unless otherwise indicated, the numerical parameters in this specification and the appended claims are approximate and can vary depending on the desired properties obtained through the teachings of this disclosure. Specifically, all numbers used in the specification and claims to express compositional amounts, reaction conditions, and the like are to be understood as being modified in all instances by the term "about." Generally, such expressions are intended to encompass variations of ±10% in some embodiments, ±5% in some embodiments, ±1% in some embodiments, and ±0.5% in some embodiments, from the specified quantity.

[0048] Furthermore, the word "comprising" does not exclude the presence of elements or steps not listed in a claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements.

[0049] The use of ordinal numbers such as "first," "second," and "third" in the specification and claims to modify corresponding elements does not in itself mean that the elements have any ordinal number, nor does it represent the order of one element relative to another or the order in the manufacturing method. The use of such ordinal numbers is only used to clearly distinguish one element with a certain name from another element with the same name.

[0050] Similarly, it should be understood that in order to streamline the present disclosure and aid in understanding one or more of the various disclosed aspects, in the above description of exemplary embodiments of the present disclosure, various features of the present disclosure are sometimes grouped together into a single embodiment, figure, or description thereof. However, this disclosed approach should not be interpreted as reflecting an intention that the claimed disclosure requires more features than are expressly recited in each claim. Rather, as reflected in the claims below, the disclosed aspects consist of fewer than all the features of the individual embodiments disclosed above. Accordingly, the claims that follow the detailed description are hereby expressly incorporated into the detailed description, with each claim standing on its own as a separate embodiment of the present disclosure.

[0051] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present disclosure. It should be understood that the above are only specific embodiments of the present disclosure and are not intended to limit the present disclosure. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present disclosure should be included in the scope of protection of the present disclosure.

Claims

1. A cylinder liner for an opposed piston two-stroke engine with a variable airflow organization, characterized in that: The invention comprises a main cylinder sleeve (1) and an intake end cylinder sleeve (2) which are connected to each other in a sleeve manner, wherein the main cylinder sleeve (1) comprises a fitting end (11) near the intake port and a fixed end (12) near the exhaust port, a plurality of inner intake ports (14) are provided on the side wall of the fitting end (11) near the intake port, and a plurality of exhaust ports (15) are provided on the side wall of the fixed end (12) near the exhaust port, and the intake end cylinder sleeve (2) comprises an extended fixed end (21) and a fitting end (22), and n layers of outer intake ports of different configurations are distributed axially on the fitting end (22) of the intake end cylinder sleeve (2), wherein n ≥ 2, and the inner intake ports (14) correspond to the outer intake ports of different configurations respectively, so as to change the airflow organization form of the cylinder sleeve.

2. The opposed-piston two-stroke engine cylinder liner with a variable airflow organization according to claim 1, characterized in that: The outer wall of the mating end (11) near the air inlet is uniformly provided with a plurality of axial flat key grooves (12) along the circumferential direction, and the inner wall of the mating end (22) is uniformly provided with a plurality of axial flat keys (23) along the circumferential direction, wherein the flat keys (23) are adapted to the flat key grooves (12).

3. The opposed-piston two-stroke engine cylinder liner with a variable airflow organization according to claim 1, characterized in that: The n layers of outer air inlets on the engaging end (22) are at least two of the following: a basic air inlet (24), a high swirl ratio air inlet (25), and a high tumble ratio scavenging air inlet (26).

4. The opposed-piston two-stroke engine cylinder liner with a variable airflow organization according to claim 1, characterized in that: The invention also includes an electric control device (3), which is connected to the extended fixed end (21) of the intake end cylinder sleeve (2). The electric control device (3) drives the intake end cylinder sleeve (2) to move axially, so that the positions of the outer air inlets of different configurations correspond to the inner air inlet (14) on the main cylinder sleeve (1).

5. The opposed-piston two-stroke engine cylinder liner with a variable airflow organization according to claim 4, characterized in that: The power control device (3) includes a linear stepping motor (31), a driver (33) and a controller (34), wherein the linear stepping motor (31) is connected to the extended fixed end (21) of the cylinder sleeve (2) at the air intake end, and the controller (34) is electrically connected to the driver (33) to convert a user instruction into a pulse signal and transmit it to the driver (33), and the driver (33) is electrically connected to the linear stepping motor (31) to convert the pulse signal into an angular displacement and transmit it to the linear stepping motor (31).

6. The opposed-piston two-stroke engine cylinder liner with a variable airflow organization according to claim 5, characterized in that: There are two linear stepper motors (31), and the two linear stepper motors (31) are symmetrically connected at the extended fixed end (21) of the cylinder sleeve (2) at the air intake end, with the diameter as the symmetry axis.

7. The opposed-piston two-stroke engine cylinder liner with a variable airflow organization according to claim 6, characterized in that: The two linear stepping motors (31) are respectively connected to a first displacement sensor (331) and a second displacement sensor (332), and the first displacement sensor (331) and the second displacement sensor (332) are used to respectively detect the displacement amounts of the two linear stepping motors (31) so that the displacement amounts of the two linear stepping motors (31) are the same.

8. The opposed-piston two-stroke engine cylinder liner with a variable airflow organization according to claim 5, characterized in that: The linear stepping motor (31), the driver (33), and the controller (34) are all electrically connected to the DC power supply (32).

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