Diesel engine piston experimental device

Abstract

The utility model provides a diesel engine piston experiment device which comprises a piston model, a transmission mechanism, a simulation cylinder cover and an experiment table. The piston model is located in an inner cavity of the simulation cylinder cover; the simulation cylinder cover is installed on the experiment table, the bottom of the piston model is connected with the piston rod, and the piston rod is connected with the transmission mechanism. A combustion chamber is arranged on the upper surface of the piston model; an oil nozzle is arranged at the top of an inner cavity of the simulated cylinder cover; the piston model is internally provided with an annular cooling cavity, and the bottom of the inner cavity of the simulation cylinder cover is provided with a cooling liquid nozzle aligned with the inlet; the piston model is of a split structure, the split structure with the combustion chamber is the upper portion of the piston, and the side wall of the combustion chamber is partially or completely provided with an oleophylic coating. According to the utility model, the detonation process of different combustion chambers can be simulated, the combustion chamber temperature fields of oleophylic coatings in different areas can be simulated, and experimental data is provided for later optimization of the piston combustion chamber.

Description

Technical Field

[0001] This utility model relates to the field of diesel engine pistons, and in particular to a diesel engine piston experimental device. Background Technology

[0002] The piston is a core component of an internal combustion engine, and its performance directly affects the engine's power, efficiency, and emissions. In an internal combustion engine, the piston operates under high temperature, high pressure, and high frequency conditions, making accurate control and understanding of its temperature distribution crucial.

[0003] Internal combustion engines are susceptible to uncontrollable factors such as vibration during operation. This vibration alters the heat transfer characteristics within the cylinder, resulting in an uneven temperature field in the cylinder head. Under these conditions, accurate analysis of the cylinder head's heating status through computer simulation is impossible. Existing experimental setups cannot conveniently simulate pistons in different combustion chambers, nor can they simulate the temperature field of areas with different oleophilic coatings. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a diesel engine piston experimental device. The piston model is a split structure, with a combustion chamber at the top. The combustion chamber sidewall is partially or completely coated with an oleophilic coating, which can simulate the detonation process in different combustion chambers and the combustion chamber temperature field of different oleophilic coating areas, providing experimental data for subsequent optimization of the piston combustion chamber.

[0005] This utility model achieves the above-mentioned technical objectives through the following technical means.

[0006] A diesel engine piston experimental apparatus includes a piston model, a transmission mechanism, a simulated cylinder head, and an experimental platform;

[0007] The piston model is located inside the simulated cylinder head; the simulated cylinder head is mounted on an experimental platform, and a piston rod is connected to the bottom of the piston model. The piston rod is connected to a transmission mechanism to drive the piston model to reciprocate within the simulated cylinder head; a combustion chamber is provided on the upper surface of the piston model, and a fuel injector is provided at the top of the simulated cylinder head cavity. The fuel injector is connected to the fuel supply system and is used to inject diesel fuel into the combustion chamber; an annular cooling chamber is provided inside the piston model, with an inlet and an outlet. A coolant nozzle aligned with the inlet is provided at the bottom of the simulated cylinder head cavity for spraying coolant into the cooling chamber.

[0008] The piston model is a split structure, with the upper part of the piston having a combustion chamber. The side wall of the combustion chamber is partially or completely coated with an oleophilic coating. By replacing the upper part of the piston with different shapes of combustion chambers, the detonation process of different combustion chambers can be simulated.

[0009] Furthermore, the piston model includes a lower piston part and an upper piston part. The lower piston part is connected to the piston rod, and the upper piston part has an arc-shaped groove on its surface. The space inside the arc-shaped groove is a combustion chamber. The upper piston part and the lower piston part are fitted together by a stop.

[0010] Furthermore, the combustion chamber is W-shaped or Ω-shaped.

[0011] Furthermore, the cooling chamber is located inside the lower part of the piston, or the cooling chamber is located between the upper part of the piston and the lower part of the piston.

[0012] Furthermore, the combustion chamber includes a combustion chamber bottom and a combustion chamber side, the combustion chamber bottom extending to the upper end face of the piston via the combustion chamber side; the combustion chamber side is partially or entirely provided with an oleophilic coating.

[0013] Furthermore, the sidewall of the combustion chamber is divided into several fan-shaped areas, each of which is provided with an oleophilic coating with a contact angle ranging from 10° to 30°.

[0014] Furthermore, the sidewall of the combustion chamber is divided into several fan-shaped regions, and these fan-shaped regions are further divided into two non-adjacent groups. Only the fan-shaped regions in the first group are provided with an oleophilic coating, or only the fan-shaped regions in the second group are provided with an oleophilic coating, or the fan-shaped regions in the first group and the fan-shaped regions in the second group are provided with oleophilic coatings with different contact angles.

[0015] Furthermore, at least one combustion chamber temperature measuring point is provided on the side of the combustion chamber to measure the temperature change of the combustion chamber; by simulating the combustion process, the temperature field of the combustion chamber with the oleophilic coating is obtained.

[0016] Furthermore, when the cooling chamber is located between the upper part and the lower part of the piston, an upper cooling chamber is provided at the bottom of the upper part of the piston. The upper cooling chamber is partially or entirely provided with an oleophilic coating. The upper cooling chamber is provided with at least one temperature measuring point at the top of the cooling chamber. By simulating the combustion process, it is used to measure the different temperature field distribution of the upper cooling chamber when there is an oleophilic coating and when there is no oleophilic coating.

[0017] Furthermore, the fuel injector is mounted on the top of the simulated cylinder head cavity via a spherical bearing. The fuel injector is supported on the inner ring, and the tail of the fuel injector is connected to an angle fixing device. By manually adjusting the posture of the fuel injector and fixing the posture of the fuel injector via the angle fixing device, the fuel injector can be aligned with different parts of the combustion chamber.

[0018] The beneficial effects of this utility model are as follows:

[0019] 1. The diesel engine piston experimental device of this utility model has a split structure for the piston model. The upper part of the piston has a combustion chamber. The side wall of the combustion chamber is partially or completely covered with an oleophilic coating. It can simulate the detonation process of different combustion chambers and the combustion chamber temperature field of different oleophilic coating areas, providing experimental data for later optimization of the piston combustion chamber.

[0020] 2. The diesel engine piston experimental device of this utility model may have a partial or complete oleophilic coating in the upper cooling chamber. The upper cooling chamber is provided with at least one temperature measuring point at the top of the cooling chamber. The different temperature field distributions of the cooling chamber with and without the oleophilic coating can be measured experimentally, providing temperature field data for the design of the piston cooling channel.

[0021] 3. The diesel engine piston experimental device of this utility model has several fan-shaped regions divided into two non-adjacent groups. Only the fan-shaped regions in the first group can be provided with an oleophilic coating, or only the fan-shaped regions in the second group can be provided with an oleophilic coating. Alternatively, the fan-shaped regions in the first group and the fan-shaped regions in the second group can be provided with oleophilic coatings with different contact angles. This allows for the study of the influence of the oleophilic coatings in different fan-shaped regions on the entire combustion chamber detonation process.

[0022] 4. In the diesel engine piston experimental device of this utility model, the fuel injector is mounted on the top of the simulated cylinder head cavity through a joint bearing. By manually adjusting the posture of the fuel injector, the fuel injector can be aligned with different parts of the combustion chamber, thus simulating the optimal injection angle of combustion chambers of different shapes. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings described below are some embodiments of this utility model. For those skilled in the art, it is obvious that other drawings can be obtained from these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the diesel engine piston experimental device described in this utility model.

[0025] Figure 2 This is a cross-sectional view of the piston model in Example 1.

[0026] Figure 3 This is a schematic diagram of the combustion chamber partitioning in Example 1.

[0027] Figure 4 This is a cross-sectional view of the piston model in Example 2.

[0028] Figure 5 This is a schematic diagram of the combustion chamber partitioning in Example 2.

[0029] Figure 6 This is a diagram showing the installation of a fuel injector.

[0030] In the picture:

[0031] 1-Piston model; 1-1-Lower piston; 1-2-Upper piston; 1-3-Cooling chamber; 1-3-1-Upper cooling chamber; 1-3-2-Lower cooling chamber; 1-4-Combustion chamber; 1-4-1-Bottom of combustion chamber; 1-4-2-Side of combustion chamber; 2-Transmission mechanism; 3-Simulated cylinder head; 4-Experimental platform; 5-Joint bearing; 6-Coolant nozzle; 7-Controller; 8-Fuel injector. Detailed Implementation

[0032] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this utility model, and should not be construed as limiting this utility model.

[0033] In the description of this utility model, it should be understood that the terms "center," "longitudinal," "transverse," "length," "width," "thickness," "upper," "lower," "axial," "radial," "vertical," "horizontal," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0034] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0035] like Figure 1As shown, the diesel engine piston experimental device of this utility model includes a piston model 1, a transmission mechanism 2, a simulated cylinder head 3, and an experimental platform 4. The piston model 1 is a scaled-down model of an actual piston. The piston model 1 is located in the inner cavity of the simulated cylinder head 3, and a sealing ring is installed between the piston model 1 and the inner cavity wall. The simulated cylinder head 3 is mounted on the experimental platform 4, and a piston rod is connected to the bottom of the piston model 1. The piston rod is connected to the transmission mechanism 2 and is used to drive the piston model 1 to reciprocate within the simulated cylinder head 3. The transmission mechanism 2 is generally a crank-slider mechanism or a hydraulic cylinder, located within the experimental platform 4. In the embodiments, it is preferred to directly connect the piston rod to the hydraulic cylinder's extension rod. When the transmission mechanism is a crank-slider mechanism, the crank-slider mechanism includes a crank, connecting rod, slider, and slider guide rail; the piston rod is the connecting rod of the crank-slider mechanism, the piston model 1 is the slider of the crank-slider mechanism, and the simulated cylinder head 3 is equivalent to the slider guide rail of the crank-slider mechanism; one end of the crank is connected to the drive motor, the other end of the crank is hinged to one end of the piston rod, and the other end of the piston rod is connected to the bottom of the piston model 1. When the crank rotates, it drives the piston rod to move, further allowing the simulated piston 1 to reciprocate linearly inside the simulated cylinder head 3; the upper surface of the piston model 1 is provided with a combustion chamber 1-4, and the top of the inner cavity of the simulated cylinder head 3 is provided with a fuel injector 8, which is connected to the fuel supply system and used to inject diesel fuel into the combustion chamber 1-4. The transmission mechanism 2 drives the piston rod to move, further driving the piston model 1 to move upward, and at the top dead center (i.e., the maximum stroke of the piston model 1), the diesel fuel is detonated in the combustion chamber 1-4, thus simulating the entire detonation process of the combustion chamber 1-4.

[0036] Example 1

[0037] like Figure 2As shown, the piston model 1 includes a lower piston part 1-1 and an upper piston part 1-2. The lower piston part 1-1 is connected to the piston rod by a pin. The surface of the upper piston part 1-2 is provided with an arc-shaped groove, and the space inside the arc-shaped groove is the combustion chamber 1-4. The upper piston part 1-2 and the lower piston part 1-1 are fitted together by a stop and connected together by bolts. The piston model 1 is provided with an annular cooling chamber 1-3, which has an inlet and an outlet. The cooling chamber 1-3 can be located inside the lower piston part 1-1 or between the upper piston part 1-2 and the lower piston part 1-1. Considering the sealing performance, a metal sealing gasket is provided at the sealing surface between the upper piston part 1-2 and the lower piston part 1-1. The simulated cylinder head 3 has a coolant nozzle 6 aligned with the inlet at the bottom of its inner cavity. This nozzle sprays coolant into the cooling chambers 1-3. The coolant nozzle 6 is connected to the coolant delivery system to spray coolant. This is to replicate the piston cooling scheme in the prior art. The piston in the prior art has an annular cooling chamber inside; therefore, an annular cooling chamber 1-3 is also designed in the piston model 1. This better simulates the combustion chamber temperature field of different regions with oleophilic coatings. The coolant is delivered into the annular cooling chamber 1-3 through the coolant nozzle 6 via the inlet, and after heat exchange, it flows out through the outlet. The coolant is generally cold oil or a coolant, which, due to its excellent thermal properties and strong heat conduction and heat balance capabilities, can effectively protect the diesel engine piston experimental device and extend its service life. A heater is also provided on the top of the simulated cylinder head 3, and a controller controls the heater to preheat the combustion chambers 1-4.

[0038] The diesel engine piston experimental device described in this utility model can simulate the working conditions of a diesel engine piston. Furthermore, since the piston model 1 is a split structure, including an upper piston part 1-2 which contains a combustion chamber 1-4, experiments can be conducted using upper piston parts 1-2 with combustion chambers 1-4 of different shapes. For example, the combustion chamber 1-4 can be W-shaped, Ω-shaped, or arc-shaped.

[0039] like Figure 3 As shown, the combustion chamber 1-4 includes a combustion chamber bottom 1-4-1 and a combustion chamber side 1-4-2. The combustion chamber bottom 1-4-1 extends through the combustion chamber side 1-4-2 to the upper end face of the piston 1-2. The side wall of the combustion chamber 1-4 is divided into several fan-shaped regions, each of which may be provided with an oleophilic coating with a contact angle ranging from 10° to 30°. In Example 1, the combustion chamber side 1-4-2 is divided into 10 fan-shaped regions, denoted by A to J in the figure, and each fan-shaped region is provided with an oleophilic coating with a contact angle of 10° to 30°.

[0040] Example 2

[0041] like Figure 4 As shown, the dividing line between the lower piston 1-1 and the upper piston 1-2 extends to the cooling chamber 1-3. Specifically, the upper cooling chamber 1-3-1 is located at the bottom of the upper piston 1-2, and the lower cooling chamber 1-3-2 is located at the top of the lower piston 1-1. The upper cooling chamber 1-3-1 and the lower cooling chamber 1-3-2 together form the complete cooling chamber 1-3. The upper cooling chamber 1-3-1 may be partially or entirely coated with an oleophilic coating. The upper cooling chamber 1-3-1 has at least one temperature measuring point at the top, allowing for experimental measurement of the different temperature field distributions in the cooling chamber 1-3 with and without the oleophilic coating. Furthermore, it allows for experimental analysis of the differences and similarities between the temperature field in the upper cooling chamber 1-3-1 with and without the oleophilic coating, providing experimental data on how to locally apply an oleophilic coating to the cooling chamber 1-3 within the piston. The contact angle of the oleophilic coating in the upper cooling chamber 1-3-1 is generally 5°-20°.

[0042] To study the effect of oleophilic coatings in different sector regions on the detonation process of the entire combustion chamber 1-4, several sector regions can be divided into two non-adjacent groups. Only the sector regions in the first group can be coated with oleophilic coatings, or only the sector regions in the second group can be coated with oleophilic coatings with different contact angles.

[0043] like Figure 5 As shown in the figure, the combustion chamber side 1-4-2 is divided into 10 sector-shaped regions, denoted by A to J. The first group includes regions A, C, E, G, and I; the second group includes regions B, D, F, H, and J. The sector-shaped regions in the first group are coated with an oleophilic coating with a contact angle of 10°-20°, and the sector-shaped regions in the second group are coated with an oleophilic coating with a contact angle of 20°-30°. It can also be divided into 4 or 5 groups, depending on the experimental requirements or piston size.

[0044] At least one combustion chamber temperature measuring point is provided on the side 1-4-2 of the combustion chamber to measure the temperature change of the combustion chamber 1-4. By simulating the combustion process, the temperature field of the combustion chamber 1-4 with the oleophilic coating can be obtained. The temperature field of the combustion chamber 1-4 with different oleophilic coatings in different regions can also be simulated to provide experimental data for the optimization of piston combustion in the later stage.

[0045] Temperature sensors are installed at the temperature measuring points on the top of the cooling chamber and the combustion chamber, and the temperature sensors transmit signals to the controller.

[0046] Example 3

[0047] like Figure 6As shown, the fuel injector 8 is mounted on the top of the simulated cylinder head 3 via a spherical bearing. Since the inner ring of the spherical bearing 5 can rotate around its outer ring, and the outer ring of the spherical bearing 5 is mounted on the simulated cylinder head 3, the fuel injector 8 is supported on the inner ring, allowing for free adjustment of the fuel injector 8's angle. The angle of the fuel injector 8 can be manually adjusted to align with different sectors within the combustion chamber. Because these sectors have a defined range, precise angle adjustment is unnecessary, thus saving experimental costs. The tail of the fuel injector 8 is connected to an angle fixing device. If the angle of the fuel injector 8 is determined through manual adjustment, it can be directly fixed using this device. The angle fixing device can be an inner set pin, radially installed inside the outer ring of the spherical bearing. When the inner set pin is tightened, one end presses against the inner ring of the spherical bearing, preventing rotation between the outer and inner rings and thus fixing the angle. Generally, there are two inner set pins, distributed at 90° intervals on the outer ring of the spherical bearing. By manually adjusting the orientation of the fuel injector 8 and then fixing it with an angle fixing device, the fuel injector 8 can be aligned with different parts of combustion chambers 1-4. This simulates the combustion conditions within combustion chambers of different shapes at different angles of the fuel injector 8, thus determining the optimal injection angle for the fuel injector 8. Analyzing the temperatures measured at the temperature measuring points, the angle of the fuel injector 8 with the smallest overall temperature difference and the most uniform temperature among all measuring points is selected; this angle is then considered the optimal injection angle for that combustion chamber. The angle that the fuel injector 8 needs to be aligned with can be adjusted according to the fan-shaped areas divided into different combustion chambers; simply align the fuel injector 8 with each fan-shaped area.

[0048] It should be understood that although this specification is described according to various embodiments, not every embodiment contains only one independent technical solution. This way of describing the specification is only for clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0049] The detailed descriptions listed above are merely specific descriptions of feasible embodiments of the present utility model, and are not intended to limit the scope of protection of the present utility model. All equivalent embodiments or modifications made without departing from the spirit of the present utility model should be included within the scope of protection of the present utility model.

Claims

1. A diesel engine piston testing apparatus, characterized in that, It includes a piston model (1), a transmission mechanism (2), a simulated cylinder head (3), and an experimental platform (4); The piston model (1) is located in the inner cavity of the simulated cylinder head (3); the simulated cylinder head (3) is installed on the experimental platform (4), the piston model (1) is connected to the piston rod at the bottom, and the piston rod is connected to the transmission mechanism (2) to drive the piston model (1) to reciprocate within the simulated cylinder head (3); the piston model (1) has a combustion chamber (1-4) on its upper surface, and the simulated cylinder head (3) has an injector (8) at the top of its inner cavity, which is connected to the fuel supply system and is used to inject diesel fuel into the combustion chamber (1-4); the piston model (1) has an annular cooling chamber (1-3) inside, which has an inlet and an outlet, and the simulated cylinder head (3) has a coolant nozzle (6) aligned with the inlet at the bottom of its inner cavity for spraying coolant into the cooling chamber (1-3); The piston model (1) is a split structure, with the upper part of the piston (1-2) having a combustion chamber (1-4). The side wall of the combustion chamber (1-4) is partially or completely coated with an oleophilic coating. By replacing the upper part of the piston (1-2) with different shapes of combustion chambers (1-4), the deflagration process of different combustion chambers can be simulated.

2. The diesel engine piston experimental apparatus according to claim 1, characterized in that, The piston model (1) includes a lower piston part (1-1) and an upper piston part (1-2). The lower piston part (1-1) is connected to the piston rod. The surface of the upper piston part (1-2) is provided with an arc-shaped groove, and the space inside the arc-shaped groove is the combustion chamber (1-4). The upper piston part (1-2) and the lower piston part (1-1) are fitted by a stop.

3. The diesel engine piston experimental apparatus according to claim 1, characterized in that, The combustion chamber (1-4) is W-shaped or Ω-shaped.

4. The diesel engine piston experimental apparatus according to claim 2, characterized in that, The cooling chamber (1-3) is located inside the lower part (1-1) of the piston, or the cooling chamber (1-3) is located between the upper part (1-2) of the piston and the lower part (1-1) of the piston.

5. The diesel engine piston experimental apparatus according to claim 1, characterized in that, The combustion chamber (1-4) includes a combustion chamber bottom (1-4-1) and a combustion chamber side (1-4-2). The combustion chamber bottom (1-4-1) extends through the combustion chamber side (1-4-2) to the end face of the upper part (1-2) of the piston. The combustion chamber side (1-4-2) is partially or entirely provided with an oleophilic coating.

6. The diesel engine piston test apparatus according to claim 5, characterized in that, The sidewall of the combustion chamber (1-4) is divided into several fan-shaped areas, and each fan-shaped area is provided with an oleophilic coating with a contact angle range of 10°-30°.

7. The diesel engine piston experimental apparatus according to claim 5, characterized in that, The sidewall of the combustion chamber (1-4) is divided into several fan-shaped areas. These fan-shaped areas are further divided into two non-adjacent groups. Only the fan-shaped areas in the first group are provided with an oleophilic coating, or only the fan-shaped areas in the second group are provided with an oleophilic coating, or the fan-shaped areas in the first group and the fan-shaped areas in the second group are provided with oleophilic coatings with different contact angles.

8. The diesel engine piston experimental apparatus according to claim 5, characterized in that, At least one combustion chamber temperature measuring point is provided on the side of the combustion chamber (1-4-2) to measure the temperature change of the combustion chamber (1-4); by simulating the combustion process, the temperature field of the combustion chamber (1-4) with oleophilic coating is obtained.

9. The diesel engine piston test apparatus according to claim 4, characterized in that, When the cooling chamber (1-3) is located between the upper part (1-2) and the lower part (1-1) of the piston, the bottom of the upper part (1-2) of the piston is provided with an upper cooling chamber (1-3-1), and the upper cooling chamber (1-3-1) is partially or completely provided with an oleophilic coating. The upper cooling chamber (1-3-1) is provided with at least one temperature measuring point at the top of the cooling chamber. By simulating the combustion process, it is used to measure the different temperature field distribution of the upper cooling chamber (1-3-1) with and without the oleophilic coating.

10. The diesel engine piston experimental apparatus according to claim 1, characterized in that, The fuel injector (8) is mounted on the top of the inner cavity of the simulated cylinder head (3) via a spherical bearing (5). The fuel injector (8) is supported on the inner ring. The tail of the fuel injector (8) is connected to an angle fixing device. The attitude of the fuel injector (8) is adjusted manually and fixed by the angle fixing device, so that the fuel injector (8) is aligned with different parts of the combustion chamber (1-4).

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