Dual-piston rotary direct-drive engine and unmanned aerial vehicle power system

Abstract

The application discloses a double-piston rotary direct-drive engine and a power system of a unmanned aerial vehicle. The main body structure of the engine is composed of a cylinder body (2), an upper end cover (1) and a lower end cover (3), and the cylinder body is integrally cast with a gear cabin. A power piston (6) and a compression piston (7) are cross-overlapped and installed, so that the cylinder body is divided into four independent working cavities, and one working unit is a complete four-stroke engine. The end faces of the two pistons are provided with spherical pits (18), and the spherical pits are adhered to form a spherical combustion chamber when the two pistons are close to each other. The power output shaft (4) can output power at both ends. The gear transmission system makes the compression piston rotate intermittently, all gears and bearings are powder metallurgy oil-containing materials, and the inner wall of the cylinder is covered with a composite functional coating, so that self-sealing, self-lubrication and maintenance-free are realized. The core components of the application are less than 10, the peak power-to-weight ratio reaches 8.1 kW / kg, and the maintenance cost is reduced by 95%.

Description

Technical Field

[0001] This invention relates to the field of power plant technology, specifically to a dual-piston rotary direct-drive engine and a drone power system including the engine. Background Technology

[0002] Taking the 2.0T hybrid engine used in the recently maiden flight of the Rainbow YH-1000S unmanned transport aircraft as an example, this engine was jointly developed by Dongfeng Motor Research Institute and the 11th Academy of Aerospace Science and Technology. It has a power-to-weight ratio of 1.87kW / kg and is based on a mature automotive engine with a parts commonality rate of up to 90%. Although it has achieved the cross-border application of "automotive engines on airplanes", it still needs to retain a complex lubrication system and sealing system, which cannot fundamentally solve the technical problems of complex structure and frequent maintenance.

[0003] Furthermore, while high-end international drone engines such as the Suter FOA 660 are designed specifically for aviation (power-to-weight ratio of approximately 2.2 kW / kg), they require regular maintenance. Existing engines generally suffer from problems such as complex structure, frequent maintenance, low power density, and limited compression ratio. Summary of the Invention

[0004] This invention aims to provide an engine that, starting from the design source, completely eliminates the traditional lubrication system and sealing device through technologies such as integral casting, dual-piston cross-shaped design, spherical combustion chamber, and composite functional coating, thereby solving the technical problems of complex structure, frequent maintenance, low power density, and limited compression ratio in the prior art.

[0005] Technical solution

[0006] The core inventive concept of this invention lies in realizing an engine with a single component. Its main structure consists of a cylinder block, an upper end cover, and a lower end cover. The cylinder block and gear compartment are integrally cast, and the upper and lower end covers are connected to the cylinder block. Inside the cylinder, two pistons are cross-overlapping and mounted to form four independent working chambers, independently completing a four-stroke cycle within a single unit.

[0007] To achieve the above concept, the present invention provides the following technical solution:

[0008] 1. Overall Structure

[0009] A dual-piston rotary direct-drive engine includes a cylinder block (2), a power output shaft (4), a power piston (6), a compression piston (7), and a hollow shaft (9). The cylinder block (2) is integrally cast with the gear housing, and an upper end cover (1) and a lower end cover (3) are bolted to the cylinder block. The power piston (6) is fixedly connected to the power output shaft (4), and the compression piston (7) is fixedly connected to the hollow shaft (9). The hollow shaft (9) is coaxially sleeved on the outside of the power output shaft (4). The power piston (6) and the compression piston (7) are installed in a cross-shaped overlapping configuration, dividing the cylinder block into four independent working chambers. The engine also includes a gear transmission system that causes the compression piston to rotate intermittently.

[0010] 2. Gear transmission system

[0011] The gear transmission system includes a driving gear 1 (13), a driven gear 1 (14), a driving gear 2 (12), a driven gear 2 (11), and a short shaft (10); the driving gear 1 (13) is fixed to the power output shaft (4) and meshes with the driven gear 1 (14); the driven gear 1 (14) and the driving gear 2 (12) are coaxially fixed on the short shaft (10); the driving gear 2 (12) meshes with the driven gear 2 (11), and the driven gear 2 (11) is fixed on the hollow shaft (9); the driven gear 1 (14) is a grooved wheel structure.

[0012] 3. Combustion chamber system

[0013] Both the power piston (6) and the compression piston (7) have spherical recesses (18) on their end faces. When the two pistons move close to each other, the two recesses fit together to form a spherical combustion chamber.

[0014] 4. Composite functional coating system

[0015] The inner wall of the cylinder and the surface of the piston are covered with a composite functional coating. The coating is based on zirconia ceramic and contains a uniformly distributed tin-coated tungsten hard phase and a tin-coated graphite lubricating phase, which realizes three major functions: thermal barrier, self-lubrication, and self-wearing phase.

[0016] 5. Self-lubricating system

[0017] All gears and bearings are made of powder metallurgy oil-impregnated materials. The bottom of the bearing housing is equipped with an annular oil storage cavity, which is connected to the inner hole of the bearing through a micro-drainage channel, achieving maintenance-free operation throughout the entire life cycle.

[0018] Beneficial effects

[0019] (1) Extremely simple structure: ≤10 core components, which is more than 90% less than traditional engines.

[0020] (2) Zero maintenance design: Powder metallurgy oil-containing materials + composite functional coating, reducing maintenance costs by more than 95%.

[0021] (3) Ultra-high compression ratio: The spherical combustion chamber combined with the high compression ratio significantly improves thermal efficiency.

[0022] (4) Dual-end output: One engine can drive two loads at the same time, reconstructing the power layout of the UAV.

[0023] (5) High power density: The power-to-weight ratio reaches 8.1kW / kg (peak condition), which is significantly better than traditional aero engines.

[0024] (6) Low vibration: Double piston cross-shaped balance structure, vibration acceleration ≤0.15g. Attached Figure Description

[0025] Figure 1 Exterior view of a dual-piston rotary direct-drive engine

[0026] Figure 2 Cross-sectional view of a dual-piston rotary direct-drive engine

[0027] Figure 3 Top view of a dual-piston rotary direct-drive engine (showing four working chambers)

[0028] Figure 4 Schematic diagram of intake, exhaust, and ignition of a dual-piston rotary direct-drive engine.

[0029] Figure 5 Piston structure diagram of a dual-piston rotary direct-drive engine (showing a spherical indentation)

[0030] Figure 6 Schematic diagram of the first stage transmission gear of a dual-piston rotary direct-drive engine

[0031] Figure 7 Schematic diagram of the second-stage transmission gear of a dual-piston rotary direct-drive engine

[0032] Figure 8 3D renderings of components of a dual-piston rotary direct-drive engine

[0033] Figure 9 3D drawings of parts for a dual-piston rotary direct-drive engine Detailed Implementation

[0034] Example: Dual-piston rotary direct-drive engine for 200kW-class unmanned aerial vehicles

[0035] 1. Overall Structure:

[0036] Refer to Figure-1 and Figure-2:

[0037] The engine consists of a cylinder block (2), an upper end cover (1), and a lower end cover (3). The cylinder block (2) is integrally cast with the gear compartment, and the upper end cover (1) and the lower end cover (3) are bolted to the cylinder block respectively. The cylinder block contains a piston chamber and a gear compartment, which are separated by a bulkhead (8).

[0038] 2. Piston and working chamber:

[0039] 3. Refer to Figure 3:

[0040] The power piston (6) and the compression piston (7) are installed in a cross-shaped overlap in the cylinder body, dividing the cylinder body into four independent working chambers. The outer cylindrical surface of the piston slides against the inner wall of the cylinder body.

[0041] 4. Power transmission:

[0042] Refer to Figure 2:

[0043] (1) The driving wheel 1 (13) is fixed to the power output shaft (4) and meshes with the driven wheel 1 (14). The driven wheel 1 is a grooved wheel structure.

[0044] (2) The driven wheel 1 and the driving wheel 2 (12) are coaxially fixed on the short shaft (10).

[0045] (3) The driving wheel 2 meshes with the driven wheel 2 (11), the driven wheel 2 is fixed on the hollow shaft (9), and the hollow shaft is fixed to the compression piston (7).

[0046] (4) When the power output shaft (4) rotates, the driving wheel 1 drives the driven wheel 1 to rotate intermittently, the driven wheel 1 drives the driving wheel 2 to rotate intermittently, the driving wheel 2 drives the driven wheel 2 to rotate intermittently, thereby driving the compression piston to rotate intermittently.

[0047] 4. Combustion chamber:

[0048] Refer to Figures 4 and 5:

[0049] Both the power piston (6) and the compression piston (7) have spherical recesses (18) on their end faces. When the two pistons move close to each other, the two recesses fit together to form a spherical combustion chamber.

[0050] 5. Gas distribution and ignition:

[0051] Refer to Figure 4:

[0052] The cylinder block (2) has an intake port (15), an exhaust port (17), and a spark plug mounting hole (16) on its side wall. The spark plug mounting hole is located near the top dead center, and the exhaust port is located near the bottom dead center. The electronic control unit (ECU) is built into the gear compartment and uses a position sensor to detect the angular position of the drive wheel 2 (12) to control the intake solenoid valve, the exhaust solenoid valve, and the ignition timing.

[0053] 6. Self-lubricating:

[0054] Both gears and bearings are made of powder metallurgy oil-impregnated materials, and the bearing housing has an annular oil storage cavity at the bottom.

[0055] As an optional implementation, the spark plug can also be located inside the gear compartment, at the bottom of the cylinder corresponding to the top dead center position. This arrangement can shorten the detection, control, and execution distance of the electronic control unit (ECU), simplify the structure, and improve signal transmission stability. A fan can be installed inside the gear compartment for forced ventilation to optimize heat dissipation. The above solutions can be selected and adopted according to actual engineering requirements.

Claims

1. A dual-piston rotary direct-drive engine, comprising a cylinder block (2), a power output shaft (4), a power piston (6), a compression piston (7), and a hollow shaft (9), characterized in that, The cylinder body (2) is integrally cast with the gear compartment, and the upper end cover (1) and lower end cover (3) are bolted to the cylinder body respectively; the power piston (6) is fixed to the power output shaft (4), the compression piston (7) is fixed to the hollow shaft (9), and the hollow shaft (9) is sleeved on the outside of the power output shaft (4); the power piston (6) and the compression piston (7) are installed in a cross-shaped overlapping manner, dividing the cylinder body into four independent working chambers; the engine also includes a gear transmission system, which makes the compression piston rotate intermittently.

2. The engine according to claim 1, characterized in that, The gear transmission system includes a driving gear 1 (13), a driven gear 1 (14), a driving gear 2 (12), a driven gear 2 (11), and a short shaft (10); the driving gear 1 (13) is fixed to the power output shaft (4) and meshes with the driven gear 1 (14); the driven gear 1 (14) and the driving gear 2 (12) are coaxially fixed to the short shaft (10); the driving gear 2 (12) meshes with the driven gear 2 (11), and the driven gear 2 (11) is fixed to the hollow shaft (9).

3. The engine according to claim 1, characterized in that, Both the power piston (6) and the compression piston (7) have spherical recesses (18) on their end faces. When the two pistons move close to each other, the two recesses fit together to form a spherical combustion chamber.

4. The engine according to claim 1, characterized in that, The power output shaft (4) may extend from the upper end and / or the lower end.

5. The engine according to claim 1, characterized in that, The inner wall of the cylinder and the surface of the piston are covered with a composite functional coating.

6. The engine according to claim 1, characterized in that, At least one gear in the engine is a powder metallurgy oil-impregnated gear.

7. The engine according to claim 1, characterized in that, At least one bearing in the engine is a powder metallurgy oil-impregnated bearing, and an annular oil reservoir is provided at the bearing housing position.

8. A power system for an unmanned aerial vehicle (UAV), characterized in that, It includes at least one engine as described in any one of claims 1-7.

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