An aviation heavy oil piston engine system

Abstract

An aviation heavy oil piston engine system includes a water-cooled piston engine. The cooling jacket of the water-cooled piston engine is provided with a liquid inlet and a liquid outlet. The liquid inlet and the liquid outlet are respectively connected to the outlet and the inlet of a radiator water tank through a circulating water path. A circulating pump is installed on the circulating water path. A radiator fan is installed on the upper part of the radiator water tank. A temperature control switch A is installed on the radiator water tank. A temperature control switch B is installed on the cooling jacket. The temperature control switch B is connected in the cooling circuit of the circulating pump. The radiator fan is rectangular. Four fixing columns are fixedly arranged around the radiator fan. A wind shield is fixedly installed at the upper ends of the fixing columns. An electric heating device is fixedly connected to the oil chamber of the carburetor. The fuel supply system includes a heavy oil tank, an oil pump, and also includes a small oil tank. The cost of the present invention is very low.

Description

Technical Field

[0001] The present invention relates to an aviation piston engine, and particularly to an aviation heavy oil piston engine system, belonging to the technical field of aviation piston engines. Background Art

[0002] The advantages of aviation heavy oil piston engines are well-known in the industry. In some scenarios, such as forest fire prevention and operations in densely populated areas, heavy oil must even be used. The progress of such engines was introduced in detail in the Internet literature "Advances in Heavy Oil Technology for Small Power Aviation Piston Engines" (Hangrui Power, Hangrui Power, https: / / view.inews.qq.com / a / 20220909A06BXU00; https: / / new.qq.com / rain / a / 20220909A06BXU00). According to some records in this article, there are two innovative solutions for small power piston engines. The first is to improve the existing carburetor, and the second is to adopt a new fuel supply method. Among them, the existing carburetor improvement method still uses carburetor fuel supply, but the intake system, carburetor, and ignition system are designed and changed according to the characteristics of heavy oil fuel, and at the same time, a preheating system for auxiliary starting is added. A typical system is the heavy oil engine solution of the German 3W company. In order to achieve reliable atomization and combustion organization of heavy oil, a number of improvement measures have been adopted for heavy oil engines, specifically as follows: an acceleration tube is used in the intake system; the pump diaphragm type carburetor is improved, and its working mode is close to that of a mechanical injection system; the crankcase is preheated; the compression ratio is reduced; a glow plug is added for starting; the ignition system is changed. This method requires a very large number of design changes to the engine, and there are also many places to be changed. Therefore, there are many factors to be changed for the heavy oil piston engine that still uses the carburetor fuel supply method, more accessories are added, the design is relatively complex, and it is more difficult to implement the improvement.

[0003] The second type is mechanical injection and electronic injection. The basic idea is to improve the electronic fuel injection system of traditional large-displacement engines or conduct a completely new innovative design according to the requirements of aero piston engines. Typical systems include the AADI (Air Assistant Direct Injection) air-assisted injection system of Australia's Orbital Corporation, the injection system based on MEMS microelectromechanical technology of the US NWUAV Corporation, the DFI micro high-pressure direct injection system of the US JM Harwood Corporation, and the MFVI (Multiple Fixed-Volume Injection) small-scale micro multi-injection system proposed by Beihang University. The AADI air-assisted injection system of Australia's Orbital Corporation has been adopted by Germany's Hirth Corporation for the development of heavy fuel aero engines. The air-assisted injection system uses an integrated nozzle, and good atomization of fuel is achieved by the impact of high-pressure air on fuel particles; by adjusting the auxiliary air pressure and the air entrainment time, different spray patterns can be obtained to adapt to different combustion chamber shapes and spark plug positions. Hirth Corporation has achieved in-cylinder direct injection of two-stroke heavy fuel engines through the air-assisted injection system, reducing the short-circuit fuel loss during the scavenging process and greatly improving the economy; combined with the stratified intake air guidance organization, the arrangement of spark plugs and nozzles, the combustion conditions have been improved and the combustion efficiency has been greatly improved. According to the actual working characteristics of small-power heavy fuel aero piston engines and the previous development experience of fuel injection systems, the Micro and Small Engine and Distributed Energy Laboratory of Beihang University has proposed a structure of a small-scale micro multi-injection system. This system is a low-pressure constant-volume multi-injection system, and the volume of fuel inhaled by the injector each time is fixed. The fuel quantity adjustment is achieved by the number of injections. According to the records of this article, many of the above technologies are still in the R & D stage and have not made progress in market applications.

[0004] Relying on a large-scale application scenario, the applicant has also conducted application-oriented explorations on the use of heavy oil in aviation piston engines. For example, in the heavy oil aviation piston engine heating control system with Chinese patent number 202121812456X and the aviation engine fuel inlet preheating device with Chinese patent number 2021218124358, relevant parts of the engine are designed for heavy oil respectively to make the heavy oil easy to atomize and burn in the engine. When the above two technical solutions are combined and used in an electronically controlled fuel injection engine with preheating, heavy oil can be used as fuel. However, in the market promotion and application, due to the relatively complex control system, fuel injection system, thermal management system, etc. of the electronically controlled fuel injection, the cost is too high. Taking a heavy oil electronically controlled fuel injection engine with a displacement of 170cc and preheating sold by a domestic company as an example, its selling price is as high as 288,000 yuan, which also leads to a high cost of the unmanned aerial vehicle manufactured with this engine. Its high price has become a major obstacle to the market application of the unmanned aerial vehicle using heavy oil as fuel. The difficulty in entering the market on a large scale will of course also hinder its own technological development. Summary of the Invention

[0005] The purpose of the present invention is to overcome the above problems existing in the current aviation piston engine using heavy oil as fuel, and to provide an aviation heavy oil piston engine system.

[0006] To achieve the purpose of the invention, the following technical solution is adopted: an aviation heavy oil piston engine system, including a water-cooled piston engine, the water-cooled piston engine is configured with a carburetor, the carburetor is connected to a fuel supply system, the cooling jacket of the water-cooled piston engine has a liquid inlet and a liquid outlet, the liquid inlet and the liquid outlet are respectively connected to the outlet and the inlet of a radiator through a circulating water path, a circulating pump is installed on the circulating water path, a radiator fan is installed on the upper part of the radiator, the blowing direction of the radiator fan blows towards the radiator, a temperature control switch A is installed on the radiator, the temperature control switch A is connected in the power supply circuit of the radiator fan, a temperature control switch B is installed on the cooling jacket, the temperature control switch B is connected in the heat dissipation circuit of the circulating pump, the radiator fan is rectangular, four fixing columns are fixedly arranged around the radiator fan, a wind baffle is fixedly installed at the upper end of the fixing columns, the wind baffle covers the entire area of the radiator fan, and there is a gap between the wind baffle and the upper surface of the radiator fan;

[0007] An electric heating device is fixedly connected to the oil chamber of the carburetor, a temperature measuring device is also fixedly connected to the oil chamber of the carburetor, the temperature measuring device is connected to a controller, and the controller controls the electric heating device;

[0008] The described fuel supply system includes a heavy oil tank and an oil pump, and also includes a small oil tank. The small oil tank is a sealed tank. The inlet end of pipeline A is located near the bottom inside the small oil tank, and the outlet end is directly or indirectly connected to the inlet of the oil pump. The inlet end of pipeline B is located near the bottom inside the heavy oil tank, and the outlet end is located near the upper opening inside the small oil tank. The outlet of the oil pump is connected to the carburetor through an oil outlet pipe. Before the engine starts, heavy oil is filled in the heavy oil tank, and gasoline is filled in the small oil tank. The liquid level of the gasoline is lower than the outlet end of pipeline B.

[0009] Furthermore, both left and right sides of the wind deflector are flat surfaces, and the middle part is an upwardly convex arc surface.

[0010] Furthermore, the electric heating device is an electric heating sheet, and the electric heating sheet is fixedly attached to the oil chamber of the carburetor.

[0011] Furthermore, the electric heating device is a heating block. At least two holes are provided on the heating block. A temperature control switch C is fixedly arranged in one of the holes, and electric heating rods are installed in the other holes. The temperature control switch C is connected in the heating electric circuit of the electric heating rods. The heating block is fixedly connected to the bottom surface of the oil chamber of the carburetor.

[0012] Furthermore, the heating block is vertically aligned with the main metering orifice of the carburetor.

[0013] Furthermore, the upper end of the heating block passes through the bottom surface of the carburetor, and the heating block is in contact with the oil in the carburetor.

[0014] Furthermore, an oil discharge pipeline communicating with the oil chamber is provided on the bottom surface of the carburetor or the heating block, and an oil discharge switch is installed on the oil discharge pipeline.

[0015] Furthermore, the small oil tank has an upper cover, the tank body of the small oil tank is screwed onto the upper cover, and both pipeline A and pipeline B are fixedly connected to the upper cover.

[0016] The positive and beneficial technical effects of the present invention are as follows: The technical solution of the present invention can achieve combustion of heavy oil through simple technical transformation on the current gasoline-fueled aviation carburetor piston engine, and the cost is very low. The cost is less than one-tenth of the currently available aviation piston heavy oil engines on the market. This will greatly promote the popularization and application of aviation piston heavy oil engines on unmanned aerial vehicles. Moreover, this engine system only requires a small amount of gasoline during startup, and the gasoline is basically completely consumed after takeoff. Therefore, this engine system can also be applied in occasions such as forest fire prevention where gasoline fuel is prohibited and operations in crowded areas. Description of the Drawings

[0017] Figure 1 is a schematic diagram of the engine temperature guarantee system of the present invention.

[0018] Figure 2It is a side view schematic diagram of the radiator.

[0019] Figure 3 It is a front view schematic diagram with an arc-shaped wind deflector.

[0020] Figure 4 It is a schematic diagram of the fuel supply system.

[0021] Figure 5 It is Figure 4 a schematic diagram of the carburetor part in

[0022] Figure 6 It is a schematic diagram of another embodiment of carburetor heating. Detailed implementation manners

[0023] To more fully explain the implementation of the present invention, implementation examples of the present invention are provided. These implementation examples are only for the elaboration of the present invention and do not limit the scope of the present invention.

[0024] The present invention is further explained in detail in conjunction with the attached drawings. The marks in the drawings are as follows:

[0025] 1: Engine; 2: Cylinder; 3: Cooling jacket; 4: Liquid inlet; 5: Liquid outlet; 6: Temperature control switch B; 7: Radiator; 8: Outlet; 9: Inlet; 10: Temperature control switch A; 11: Circulation pump; 12: Wind deflector; 13: Cooling fan; 14: Expansion tank; 15: Fixed column; 16: Heavy oil tank; 17: Pipeline B; 18: Small oil tank; 19: Pipeline A; 20: Oil filter; 21: Oil pump; 22: Carburetor; 23: Oil chamber; 24: Heating block; 25: Heating rod; 26: Temperature control switch C; 27: Oil hole; 28: Drain switch; 29: Heating sheet.

[0026] In the present invention, innovative designs are respectively carried out on the thermal management, carburetor and fuel supply system of the current gasoline-fueled aviation piston engine, so that the engine can use heavy oil as fuel. Other parts not involved in the innovation adopt existing technologies, such as the connection between the carburetor and the engine, the cylinder of the piston engine, etc.

[0027] As shown in the attached drawings, an aviation heavy oil piston engine system includes a water-cooled piston engine 1. Figure 2 shows the cylinder of the engine. A cooling jacket 3 is fixedly connected to the cylinder head of the cylinder. The cooling jacket is provided with a liquid inlet 4 and a liquid outlet 5. The liquid inlet and the liquid outlet are respectively connected to the outlet 8 and the inlet 9 of the radiator tank 7 through a circulating water path. An expansion tank 14 is connected to the radiator tank. The function of the expansion tank is the same as that of the expansion tank in current automobiles. When the pressure in the radiator tank is high, the coolant enters the expansion tank. When the pressure in the radiator tank is low, the coolant enters the radiator tank. A circulating pump 11 is installed on the circulating water path, and a radiator fan 13 is installed on the upper part of the radiator tank. The air outlet direction of the radiator fan blows towards the radiator tank 7. The installation method of the radiator tank is the same as the installation method in the applicant's Chinese patent application No. 201922228043.6 (engine temperature controllable heat dissipation device for agricultural plant protection unmanned aerial vehicle) (the radiator tank in this application corresponds to the radiator in that patent). The above engine thermal management is the same as the engine thermal management principle of automobiles, and both are prior arts. A temperature control switch A 10 is installed on the radiator tank. The temperature control switch A is connected in the power supply circuit of the radiator fan 13. After the temperature reaches the set value of the temperature control switch A, the temperature control switch A conducts, and the radiator fan starts. When the temperature does not reach the set value of the temperature control switch A, the temperature control switch A disconnects. A temperature control switch B 6 is installed on the cooling jacket. The temperature control switch B is connected in the power supply circuit of the circulating pump 11. After the temperature reaches the set value of the temperature control switch B, the temperature control switch B conducts, and the circulating pump starts. The radiator fan is rectangular. Four fixing columns 15 are fixedly arranged around the radiator fan. A wind shield 12 is fixedly installed at the upper ends of the fixing columns. The wind shield covers the entire area of the radiator fan. There is a gap between the wind shield and the upper surface of the radiator fan. Optimally, the left and right sides of the wind shield are flat surfaces, and the middle is a convex arc surface. An example of such an arc surface is Figure 3 shown. The arc surface is free from guiding the airflow generated by the rotor.

[0028] The fuel supply system includes a heavy oil tank 16 and an oil pump 21, and also includes a small oil tank 18. The small oil tank is a sealed tank. The inlet end of pipeline A 19 is located inside the small oil tank near the bottom, and the outlet is connected to an oil filter 20. The oil filter 20 is connected to the inlet of the oil pump 21. The outlet of the oil pump is connected to a carburetor 22 through an oil outlet pipe. The inlet end of pipeline B 17 is located inside the heavy oil tank near the bottom, and the outlet end is located inside the small oil tank near the upper opening. The small oil tank has an upper cover. The tank body of the small oil tank is screwed onto the upper cover. Pipeline A and pipeline B are both fixedly connected to the upper cover. This makes it convenient to replace the small oil tank filled with gasoline before takeoff.

[0029] Before the engine starts, heavy oil is filled in the heavy oil tank, and gasoline is filled in the small oil tank. The liquid level of the gasoline is lower than the outlet end of pipeline B.

[0030] An electric heating device is fixedly connected to the fuel chamber 23 of the carburetor 22. A temperature measuring device is also fixedly connected to the fuel chamber of the carburetor. The temperature measuring device is connected to a controller, and the controller controls the electric heating device. In an embodiment of the present application, the electric heating device is a heating block 24. Two holes are provided in the heating block. A temperature control switch C26 is fixedly arranged in one of the holes, and an electric heating rod 25 is installed in the other hole. The electric heating plate is connected to a heating power supply. The temperature control switch C26 is connected in the heating electric circuit of the electric heating rod. After the temperature reaches the temperature set by the temperature control switch C, the temperature control switch disconnects to stop the heating of the heating rod. After the temperature is lower than the temperature set by the temperature control switch C, the temperature control switch C closes. The heating block is fixedly connected to the bottom surface of the fuel chamber of the carburetor. The upper end of the heating block passes through the bottom surface of the carburetor, and the heating block is in contact with the fuel in the carburetor. The heating block is directly opposite to the main fuel orifice in the carburetor. More optimally, an oil discharge pipeline 27 communicating with the fuel chamber is provided on the heating block, and an oil discharge switch 28 is installed on the oil discharge pipeline. The oil discharge switch can be a plug connected by thread. The function of the oil discharge switch is to drain the heavy oil in the carburetor during the next flight, facilitating direct starting with gasoline for the next time.

[0031] In addition to the heating rod, the electric heating device can also be an electric heating sheet, which is fixedly attached to the fuel chamber of the carburetor. The electric heating sheet can adopt a semiconductor heating sheet, etc.

[0032] It is well known in the industry that the bottleneck of using heavy oil in an aviation piston engine is that due to its high viscosity, it is not easy to atomize. In the present invention, in order to enable the use of heavy oil, innovations are made in the following aspects: one is the fuel supply system, the second is the carburetor heating, and the third is the thermal management of the engine (including a circulation pump, a radiator fan, a windshield, a temperature control switch, etc.). Since the small fuel tank contains gasoline, the engine and fuel can start smoothly without heating. After starting, the engine generates heat to complete preheating. At the same time, the fuel also changes from gasoline, a mixture of gasoline and heavy oil, to heavy oil. During the changing process, the carburetor heating is turned on to control the temperature of the carburetor above 80 degrees. When the temperature is lower than this temperature, the temperature control switch C closes to heat through the heating rod, and the heavy oil can be atomized and enter the engine through the carburetor for stable combustion and work. In order to prevent the engine temperature from being too low and affecting the combustion of heavy oil, a temperature control switch B is installed on the cooling jacket. The temperature control switch B is set to about 75 degrees. When the temperature is lower than this temperature, the circulation pump is turned off to ensure the engine temperature. It has a windshield during low-temperature flight, and the airflow of the rotor cannot carry away the heat generated by the engine, ensuring sufficient temperature of the engine during low-altitude flight. During high-load flight, the circulation pump and radiator fan start to dissipate heat from the engine to ensure its power output. When the heat dissipation of the engine is large and the water temperature in the radiator reaches above 80 degrees, the temperature control switch A closes to turn on the radiator fan to dissipate heat from the coolant.

[0033] This engine system has been very successful in application tests on drones. The heavy fuel tank uses the current fuel tank, and the small fuel tank uses an aluminum alloy medicine bottle purchased online. Approximately 100 ml of gasoline is filled in the aluminum alloy medicine bottle. A drone equipped with a 210 cc two-stroke piston engine is used. The engine itself does not have heating. The engine is equipped with a nibbi carburetor. One type of carburetor has a threaded hole with a plug at the bottom. A heating block with a heating rod and a temperature control switch is installed in this threaded hole. The temperature of the temperature control switch is set at 85 degrees. The ambient temperature is 15 degrees Celsius. The engine is directly started without heating, and the start is normal. Approximately 3 minutes after startup, the carburetor is heated, and the engine can continue to operate. The drone is controlled to take off, and the takeoff is normal. There is no obvious abnormality in flight compared with a heavy fuel engine. Later, through tests, it was also found that adding less than 100 ml of gasoline to the small fuel tank can also achieve the same result.

[0034] After the embodiments of the present invention are described in detail, those skilled in the art can clearly understand that various changes and modifications can be made without departing from the scope and spirit of the above patent application. Any simple modification, equivalent change, and modification made to the above embodiments based on the technical essence of the present invention all belong to the scope of the technical solution of the present invention, and the present invention is not limited to the embodiments described in the specification.

Claims

1. An aviation heavy oil piston engine system, including a water-cooled piston engine, the water-cooled piston engine is configured with a carburetor, the carburetor is connected to a fuel supply system, the cooling jacket of the water-cooled piston engine has a liquid inlet and a liquid outlet, the liquid inlet and the liquid outlet are respectively connected to the outlet and the inlet of a radiator through a circulating water path, a circulating pump is installed on the circulating water path, a cooling fan is installed on the upper part of the radiator, the blowing direction of the cooling fan blows towards the radiator, a temperature control switch A is installed on the radiator, and the temperature control switch A is connected in the power supply circuit of the cooling fan, and is characterized in that: A temperature control switch B is installed on the cooling jacket. The temperature control switch B is connected to the heat dissipation circuit of the circulation pump. The heat dissipation fan is rectangular. Four fixing columns are fixedly arranged around the heat dissipation fan. A wind deflector is fixedly installed at the upper ends of the fixing columns. The wind deflector covers the entire area of the heat dissipation fan. There is a gap between the wind deflector and the upper surface of the heat dissipation fan. An electric heating device is fixedly connected to the oil chamber of the carburetor. A temperature measuring device is also fixedly connected to the oil chamber of the carburetor. The temperature measuring device is connected to a controller, and the controller controls the electric heating device. The fuel supply system includes a heavy oil tank and an oil pump, and also includes a small oil tank. The small oil tank is a sealed tank. The inlet end of pipeline A is located near the bottom inside the small oil tank, and the outlet end is directly or indirectly connected to the inlet of the oil pump. The inlet end of pipeline B is located near the bottom inside the heavy oil tank, and the outlet end is located near the upper opening inside the small oil tank. The outlet of the oil pump is connected to the carburetor through an oil outlet pipe. Before the engine starts, heavy oil is loaded into the heavy oil tank, and gasoline is loaded into the small oil tank. The liquid level of the gasoline is lower than the outlet end of pipeline B.

2. The aero heavy oil piston engine system according to claim 1, characterized in that: The left and right sides of the wind deflector are flat surfaces, and the middle is a convex arc surface.

3. The aero heavy oil piston engine system according to claim 1, characterized in that: The electric heating device is an electric heating sheet, and the electric heating sheet is fixedly attached to the oil chamber of the carburetor.

4. The aero heavy oil piston engine system according to claim 1, characterized in that: The electric heating device is a heating block. At least two holes are opened in the heating block. A temperature control switch C is fixedly arranged in one of the holes, and electric heating rods are installed in the other holes. The temperature control switch C is connected to the heating electric circuit of the electric heating rods. The heating block is fixedly connected to the bottom surface of the carburetor oil chamber.

5. The aero heavy oil piston engine system according to claim 4, wherein: The heating block is vertically aligned with the main fuel orifice of the carburetor.

6. The aero heavy oil piston engine system according to claim 5, characterized in that: The upper end of the heating block passes through the bottom surface of the carburetor, and the heating block is in contact with the oil in the carburetor.

7. The aero heavy oil piston engine system according to claim 6, characterized in that: A drain pipeline communicating with the oil chamber is opened on the bottom surface of the carburetor or the heating block, and a drain switch is installed on the drain pipeline.

8. The aero heavy oil piston engine system according to claim 1, wherein: The small oil tank has an upper cover. The tank body of the small oil tank is screwed onto the upper cover. Pipeline A and pipeline B are both fixedly connected to the upper cover.

9. The aero heavy oil piston engine system according to claim 1, characterized in that: An oil filter element is installed on pipeline A between the small oil tank and the oil pump, and the oil passes through the oil filter element and then enters the oil pump.

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