Lubricating oil thermostat of four-stroke engine

Abstract

The invention discloses a four-stroke engine lubricating oil thermostat which comprises a valve body, and an inductor valve is installed in an inner cavity of the valve body. Wherein the two sides of the valve body are communicated with connectors, and the inner cavity is further provided with a flow increasing part. According to the thermostat, through the arrangement of the flow increasing part, the area of a fluid flowing channel in the thermostat is increased, after a sensor valve is completely opened, the internal flow resistance of fluid in the flowing channel is reduced, and in the flowing process of the lubricating oil, only a small part of the lubricating oil enters the cooling process of a major cycle; and the problem of excessive cooling of the lubricating oil can be avoided, so that the influence on the service life of the engine can be reduced.

Description

Technical Field

[0001] The invention relates to a four-stroke engine lubricating oil thermostat, in particular to a four-stroke engine lubricating oil thermostat suitable for a large fixed-wing unmanned aerial vehicle. Background Art

[0002] Large fixed-wing UAVs have large loading space, large loading capacity, strong power support, high system reliability, and flight safety. They can carry more high-performance mission payloads and perform support and guarantee tasks such as freight logistics, aerial seeding, and mission payload use. At present, large fixed-wing UAVs often use four-stroke aircraft engines to provide thrust. The four-stroke aircraft engine uses a combination of forced lubrication and splash lubrication. The engine camshaft drives the mechanical rotor oil pump to work, and the oil flows from the external oil tank through the oil thermostat and then pumped into the engine to lubricate the various lubrication parts inside the engine.

[0003] Since the lubricating oil of UAVs will be affected in both high and low temperature environments, it will lead to performance degradation or equipment damage. High temperature will make the lubricating oil thinner, reduce the lubrication effect, and may cause aggravated wear of bearings and gears, and even cause equipment failure. Low temperature will make the lubricating oil thicker, increase friction, and affect the smoothness of equipment operation. Therefore, in order to ensure the stable operation of the UAV engine and extend the service life of the engine, a thermostat is provided to adjust the engine lubricating oil temperature. For example, Chinese patent document CN213478421U discloses an oil thermostat, a lubrication system and an engine. Among them, the oil thermostat includes a housing, a valve core and a spring located in the housing, a retaining ring is provided at the first end of the housing, the center hole of the retaining ring constitutes the main oil inlet hole, and the retaining ring is also provided with a secondary oil inlet hole located outside the main oil inlet hole. The lubrication system includes an oil cooler and the above-mentioned oil thermostat. The engine includes the above-mentioned lubrication system. The utility model can improve the control effect of engine oil temperature by opening a plurality of auxiliary oil inlet holes on a retaining ring used for resisting a spring at the oil inlet end of the engine oil thermostat to increase the flow area of ​​the retaining ring and reduce the flow resistance.

[0004] In this prior art, although the flow resistance can be reduced by setting multiple auxiliary oil inlet holes on the retaining ring, when the UAV is flying horizontally and descending, the lubricating oil temperature will gradually decrease due to the reduction of engine load. At this time, a large amount of lubricating oil still enters the large circulation through the oil cooler for heat exchange, resulting in excessive heat dissipation, making the lubricating oil temperature too low, affecting the engine life. Summary of the invention

[0005] In order to solve the technical problem of excessive heat dissipation of lubricating oil thermostat in the prior art, the present invention provides a lubricating oil thermostat for a four-stroke engine, including a valve body, an inner cavity of the valve body is equipped with a sensor valve; wherein two sides of the valve body are connected with joints, and the inner cavity is also provided with a flow increasing portion.

[0006] In the prior art, lubricating oil enters the interior through multiple auxiliary oil inlet holes, but the internal flow resistance is still too large when passing through the auxiliary oil inlet holes, so a large amount of lubricating oil will flow into the oil cooler for heat exchange, resulting in excessive heat dissipation. In the present invention, the area of ​​the fluid flow channel inside the thermostat is increased by setting the flow increase part. After the sensor valve is fully opened, the internal flow resistance of the fluid in the flow channel is reduced. During the flow of lubricating oil, only a small part of the lubricating oil will enter the cooling process of the large cycle, which can avoid the problem of excessive cooling of the lubricating oil, thereby reducing the impact on the service life of the engine.

[0007] Preferably, the flow increasing part is located between the sensor valve and the inner wall of the valve body. In this solution, arranging the flow increasing part between the sensor valve and the inner wall of the valve body can avoid the influence of the sensor valve on the flow of lubricating oil, thereby further reducing the internal flow resistance and having a simple structure.

[0008] Preferably, the joint includes a connecting portion and a mounting portion, the mounting portion is assembled in the valve body, and the aperture of the mounting portion is larger than the aperture of the connecting portion. In this solution, after the aperture of the mounting portion is larger than the aperture of the connecting portion, the internal resistance of the lubricating oil entering the valve body can be reduced, ensuring that the lubricating oil can smoothly enter the valve body and flow, and the structure is simple.

[0009] Preferably, one of the joints is connected to the oil cooler, and when the sensor valve is completely closed, the ratio of the fluid entering the oil cooler to the total flow in the valve body is ≤10%. Considering that drones are mostly flying at high altitudes, the ambient temperature of the engine is mostly low. Therefore, in this solution, the ratio of the fluid entering the oil cooler to the total flow in the valve body is ≤10%, which can ensure that the lubricating oil will not solidify in extremely cold conditions, thereby ensuring the normal use of the lubricating oil.

[0010] Preferably, the valve body is a bilaterally symmetrical H-shaped valve body. In this solution, the valve body is bilaterally symmetrically arranged, used and installed.

[0011] Preferably, the valve body is provided with a single sensor valve body. In this solution, the provision of a single sensor can ensure that a small amount of lubricating oil enters the oil cooler for heat exchange, ensuring that the lubricating oil will not solidify in extremely cold conditions, thereby ensuring normal use of the lubricating oil.

[0012] Preferably, the sensor valve is opened when the lubricating oil temperature decreases, and the sensor valve is completely closed when the lubricating oil temperature increases. In this solution, the sensor valve is opened when the lubricating oil temperature decreases, which can reduce the lubricating oil entering the oil cooler and accelerate the warm-up; while the sensor valve is closed when the lubricating oil temperature increases, which will start a large circulation and guide most of the lubricating oil into the oil cooler for heat exchange, thereby reducing the lubricating oil temperature, and the operation is simple.

[0013] The present invention has the following beneficial effects:

[0014] 1. The present invention increases the area of the fluid flow channel inside the thermostat. After the sensor valve is fully opened, the internal flow resistance of the fluid in the flow channel decreases. During the process of lubricating oil flow, only a small part of the lubricating oil will enter the cooling process of the large cycle, thus avoiding the problem of excessive cooling of the lubricating oil and reducing the impact on the service life of the engine.

[0015] 2. The present invention can increase the lubricating oil temperature by ≥70°C when the UAV changes from level flight to descent, greatly improving the engine life.

[0016] 3. The present invention can ensure that the lubricating oil will not solidify in extremely cold conditions, thus ensuring the normal use of the lubricating oil. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of an embodiment of a lubricating oil thermostat for a four-stroke engine of the present invention;

[0018] Figure 2 It is a top view of the lubricating oil thermostat for a four-stroke engine;

[0019] Figure 3 It is Figure 2 The sectional view taken along A-A in DETAILED DESCRIPTION OF THE EMBODIMENTS

[0020] The following is a more detailed description through specific embodiments:

[0021] 1. Definition

[0022] Internal flow resistance: refers to the obstructive effect encountered by the fluid inside the pipeline or container during the fluid flow process, resulting in the phenomenon of slow fluid flow speed or reduced pressure. The internal flow resistance is mainly determined by the viscosity of the fluid and the geometric shape of the pipeline or container.

[0023] 2. The reference numerals in the accompanying drawings of the specification include: valve body 1, O-ring 2, joint 3, sensor valve 4.

[0024] The embodiment is basically as shown in Figure 1 、 Figure 2 and Figure 3 : A lubricating oil thermostat for a four-stroke engine, including a valve body 1. In this embodiment, the valve body 1 is an H-shaped valve body 1 that is symmetrical left and right. A single sensor valve 4 is installed in the inner cavity of the valve body 1. When the lubricating oil temperature decreases, the sensor valve 4 opens, and when the lubricating oil temperature increases, the sensor valve 4 is completely closed. In this embodiment, when the lubricating oil temperature ≤80°C, the sensor valve 4 opens, and when the lubricating oil temperature ≥90°C, the sensor valve 4 is completely closed.

[0025] On both sides of the valve body 1, connectors 3 are connected. An additional flow-increasing part is also provided in the inner cavity, and the additional flow-increasing part is located between the inductor valve 4 and the inner wall of the valve body 1. Among them, the connector 3 includes a connecting part and a mounting part. The mounting part is assembled inside the valve body 1, and the aperture of the mounting part is larger than that of the connecting part. In this embodiment, a total of four connectors 3 are connected to both sides of the valve body 1, with one connector 3 provided at the upper and lower ends on each side. An O-ring 2 for sealing is provided between the valve body 1 and the connector 3. Among them, the upper end of the valve body 1 is the COLD end, and the lower end of the valve body 1 is the HOT end. The connector 3 at the upper left end of the valve body 1 is connected to the engine, the connector 3 at the lower left end is connected to the lubricating oil tank, and the connectors 3 at the upper and lower right ends are both connected to the oil cooler. When the inductor valve 4 is completely closed, the proportion of the fluid entering the oil cooler to the total flow inside the valve body 1 is ≤10%.

[0026] The specific implementation process is as follows: Before use, connect the valve body 1 to the engine. The connector 3 at the upper left end of the valve body 1 is connected to the engine, the connector 3 at the lower left end is connected to the lubricating oil tank, and the connectors 3 at the upper and lower right ends are both connected to the oil cooler. During use, at the initial startup stage of the engine, the lubricating oil temperature is lower than 80°C. At this time, the inductor valve 4 is opened. After the lubricating oil enters the valve body 1 through the connector 3 at the lower left end of the valve body 1 from the lubricating oil tank, it flows through the opened inductor valve 4 and then flows out through the connector 3 at the upper left end and enters the engine. Then, during the operation of the engine, the lubricating oil temperature gradually rises. Thus, the inductor valve 4 is closed. After the lubricating oil enters the valve body 1 from the lower left connector 3, it flows out through the lower right connector 3 and enters the oil cooler for heat exchange. Then, the lubricating oil with a reduced temperature after heat exchange flows back into the valve body 1 through the upper right connector 3 and then flows into the engine through the upper left connector 3.

[0027] In this embodiment, tests are respectively carried out using the lubricating oil thermostat before improvement and the lubricating oil thermostat of the present invention after improvement, and the test data obtained are shown in the following table.

[0028]

[0029] It can be known from the above table that after adopting the improved lubricating oil thermostat in the present invention, when the unmanned aerial vehicle changes from level flight to descent, the temperature of the lubricating oil can be increased to above 70°C, which can effectively avoid the lubricating oil temperature from being too low and can greatly improve the service life of the engine.

[0030] The above are only embodiments of the present invention. Specific structures and common knowledge such as characteristics that are well-known in the art are not described in detail herein. Those of ordinary skill in the art know all the common general technical knowledge in the technical field to which the invention pertains before the filing date or the priority date, are able to know all the prior art in this field, and have the ability to apply the conventional experimental means before this date. Those of ordinary skill in the art can, under the inspiration given in this application, combine their own abilities to complete and implement this solution. Some typical well-known structures or well-known methods should not become obstacles for those of ordinary skill in the art to implement this application. It should be noted that for those skilled in the art, without departing from the structure of the present invention, several deformations and improvements can still be made, and these should also be regarded as the protection scope of the present invention, and these will not affect the implementation effect of the present invention and the practicality of the patent. The protection scope claimed in this application should be based on the content of its claims, and the specific implementation manners and the like recorded in the specification can be used to interpret the content of the claims.

Claims

1. A four-stroke engine oil thermostat, comprising a valve body, wherein an inductor valve is installed in the inner cavity of the valve body; characterized in that: Both sides of the valve body are connected with joints, and the inner cavity is also provided with a flow increasing part.

2. The four-stroke engine oil thermostat according to claim 1, characterized in that: The flow increasing portion is located between the sensor valve and the inner wall of the valve body.

3. The four-stroke engine oil thermostat according to claim 2, characterized in that: The joint comprises a connecting portion and a mounting portion, wherein the mounting portion is assembled in the valve body, and the aperture of the mounting portion is larger than the aperture of the connecting portion.

4. The four-stroke engine oil thermostat according to any one of claims 1 to 3, characterized in that: One of the connectors is connected to the oil cooler. When the sensor valve is fully closed, the proportion of the fluid entering the oil cooler to the total flow entering the valve body is ≤10%.

5. The four-stroke engine oil thermostat according to claim 4, characterized in that: The valve body is a bilaterally symmetrical H-shaped valve body.

6. The four-stroke engine oil thermostat according to claim 5, characterized in that: The valve body is provided with a single sensor valve body.

7. The four-stroke engine oil thermostat according to claim 6, characterized in that: The sensor valve opens when the lubricating oil temperature decreases, and completely closes when the lubricating oil temperature increases.

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