550 Electronic Fuel Injection Aviation Piston Engine

1. Purpose and functions of the product

The 550 Electronic Fuel Injection Aviation Piston Engine (hereinafter referred to as the “550 Engine”) is a unit that provides propulsion and electrical power to unmanned aerial vehicles (UAVs).[cite: 1]. This type of engine features a simple and reliable design, high power-to-weight ratio, compact layout and stable performance.[cite: 1].

As the propulsion system for the aircraft platform, the 550 propulsion system provides the UAV with the necessary thrust and also supplies power to the avionics.[cite: 1].

2. Characteristics and main technical indicators

2.1 Functional requirements

• Launch method: The engine is equipped with its own electric starter, providing electric starting[cite: 1].
• Cooling method: The engine has an air cooling system[cite: 1].
• Lubrication method: Lubrication is carried out by oil mist (mixed system)[cite: 1].
• Fuel type: Gasoline with an octane rating of 95 and higher[cite: 1].
• Communication functions: Capable of receiving control commands from the control computer (or integrated on-board computer) and adjusting engine speed accordingly[cite: 1]; capable of transmitting to the control computer parameters of throttle position, speed, intake temperature, cylinder temperature, exhaust gas temperature, etc.[cite: 1].

2.2 Operational requirements

2.2.1 General characteristics

• Maximum speed: ≥ 6300 rpm[cite: 1].
• Maximum power at zero altitude: ≥ 37 kW[cite: 1].
• Minimum specific fuel consumption:
  • 1) Cruise: < 380–460 g/(kWh)[cite: 1].
  • 2) Maximum power mode: < 550 g/(kWh)[cite: 1].
• Minimum stable speed: < 2000 rpm[cite: 1].
• Dimensions (L×W×H): (364±5) mm × (372±5) mm × (395±5) mm[cite: 1].
• Weight: ≤ 22.5 kg (including engine block, intake and exhaust system, injection control unit)[cite: 1].
• Appearance requirements:
  • The surface must be flat, smooth, without damage, rust, mold, stains, coating peeling, obvious scratches and burrs[cite: 1].
  • Structural parts and control elements must not have mechanical damage; connections and fasteners - without corrosion, damage, loosening and deformation; welds are smooth, without slag and cracks; plastic parts - no swelling, cracks or deformations[cite: 1].
  • Cables and harnesses must be laid rationally, with fixation and protection measures[cite: 1].
  • Text, symbols, markings and indicators must be legible[cite: 1].
• Markings and designations: The product is equipped with a nameplate indicating the name, code, serial number, production date and other information[cite: 1].

2.2.2 Launch characteristics

• Number of startup attempts: The engine should start successfully within 3 attempts[cite: 1].
• Starting at low temperatures: Can be started in low temperature conditions down to -40°C (use of auxiliary heating equipment supplied in the kit is allowed)[cite: 1].

2.2.3 Electricity generation characteristics

• Generation power: ≥ 2 kW[cite: 1].

2.3 Engineering requirements

• Reliability: Mean time between failures MTBF(01) ≥ 300 h[cite: 1].
• Maintainability: Average recovery time MTTR ≤ 1.4 h (at baseline)[cite: 1].
• Security:
  • 1) Providing a technical description, operation and maintenance manual, product form (passport) and documents confirming quality[cite: 1].
  • 2) Providing the necessary auxiliary equipment, tools, spare parts (including wearing parts, consumables and parts with limited service life) to ensure operation and repair[cite: 1].
• Security:
  • 1) Cables and connectors are protected against incorrect connection (“fool proof”)[cite: 1].
  • 2) Metal structural elements do not have sharp corners or edges[cite: 1].
  • 3) There are no oil leaks during engine operation[cite: 1].
  • 4) The engine has an overspeed protection function[cite: 1].
  • 5) The outlet of high-temperature exhaust gases is directed away from the UAV fuselage[cite: 1].
• Testability: The injection control unit is capable of monitoring throttle position, engine speed, cylinder temperature, exhaust temperature, intake temperature, fuel pressure, etc.[cite: 1].

2.3.1 Environmental conditions (Adaptability)

• Operating temperature: -50°C ~ +55°C (start at -40°C, auxiliary heating possible)[cite: 1].
• Storage temperature: -50°C ~ +65°C[cite: 1].
• Relative Humidity: (95±5)% (at 30°C ~ 60°C)[cite: 1].
• Vibration: ≥ 2g (15Hz ~ 500Hz ~ 15Hz)[cite: 1].
• Shock loads: vertically ≥ 20g, along the transverse and longitudinal axes ≥ 15g[cite: 1].
• Low pressure: Capable of withstanding low pressure conditions equivalent to 7000m altitude[cite: 1].
• Salt fog: Resistant to salt spray[cite: 1].
• Mold: Resistant to mold and mildew[cite: 1].
• Rain: Provides protection from moderate rain[cite: 1].
• Application altitude: Able to start and operate normally in high altitude conditions at altitudes of up to 5000 meters[cite: 1].

2.3.2 Electromagnetic compatibility (EMC)

• Internal Compatibility: The product is compatible when used independently[cite: 1].
• Mutual compatibility: After installation on a UAV, the product is capable of working in conjunction with other equipment of the device[cite: 1].

2.3.3 Interchangeability

• Field replaceable units (LRUs) of the same model and functionality are interchangeable[cite: 1].

№	Name	Quantity	Note
1)	Electronic injection control unit (EVT/ECU)	1 piece	[cite: 1]
2)	Spark plug	4 pcs.	[cite: 1]
3)	Ignition module (CDI)	2 pcs.	[cite: 1]
4)	Fuel injector	4 pcs.	[cite: 1]
5)	Air filter	4 pcs.	[cite: 1]
6)	Exhaust pipe	4 pcs.	[cite: 1]

2.3.4 Transport requirements

• Return transportation: The product is equipped with a special shipping container that meets the requirements of road and rail transportation[cite: 1].
• Transportation within the device: After installation on the UAV, it satisfies the requirements for transporting the device[cite: 1].

2.3.5 Resource (Service life)

• Time to first overhaul (TBO): ≥ 250 h[cite: 1].
• Shared resource: ≥ 500 h[cite: 1].

2.3.6 Software development requirements

• A modular software architecture with expandability is used; proven software is used and inherited[cite: 1].
• Software development complies with GJB 2786A-2009 General Requirements for Military Software Development, and documentation complies with GJB438B-2009 General Requirements for Military Software Documentation.[cite: 1].

3. Composition, structure and principle of operation

3.1 Product composition

The 550 engine is a four-cylinder, horizontally opposed, two-stroke, air-cooled piston engine[cite: 1]. Uses an electronic fuel injection system[cite: 1]. It consists of an engine cylinder block, an electronic injection control unit and other elements[cite: 1].

3.2 Product structure

The main components of the structure include: Engine body/block, Ignition system (including CDI and spark plugs), Fuel injection system (EV, injectors), Intake and exhaust system (Throttle body, air filter, exhaust pipe), and Integrated starting and generation system (Alternator/starter)[cite: 1].

3.3 Operating principle

• The 550 engine uses an electronic fuel injection system (EFI system)[cite: 1]. The engine uses pressure from the combustion of gasoline to drive the pistons, converting their linear reciprocating motion into rotational motion through a crank mechanism to rotate the propeller and create thrust.[cite: 1].
• The EVT system relies on various sensors to determine engine operating conditions (such as speed, intake temperature, barometric pressure, throttle angle)[cite: 1]. After calculations in the control unit (ECU) and adjustments according to the curves stored in the read-only memory (ROM), the system precisely controls the injection time and volume of the electromagnetic injectors[cite: 1]. This ensures an optimal air-fuel mixture ratio in all operating modes, achieving the best power and efficiency indicators[cite: 1].
• The electric starting system uses an integrated motor-generator (starter-generator) to rotate the engine crankshaft[cite: 1]. The motor-generator is installed directly on the engine, which greatly simplifies the starting process and makes it safe and reliable[cite: 1].

4. Technical features of the product

The main technical features of the 550 engine include:

1. Simple and reliable design, low weight, space-saving layout[cite: 1].
2. High operating efficiency (efficiency), high power-to-weight ratio[cite: 1].
3. Integrated starter-generator design with main engine block - highly integrated, easy to operate and maintain[cite: 1].

5. Interfaces

5.1 Mechanical interfaces

• 5.1.1 Installation interface on the UAV body: The installation dimensions of the motor bracket for mounting on the UAV body have a tolerance of ±0.5 mm[cite: 1].
• 5.1.2 Propeller installation interface: According to the assembly drawing[cite: 1].
• 5.1.3 Fuel system interfaces:
  • a) 1 fuel supply channel (input)[cite: 1];
  • b) 1 fuel return channel (return)[cite: 1].

5.2 Electrical interfaces

• a) 1 DC input interface[cite: 1];
• b) 1 CAN bus interface[cite: 1];
• c) 1 full duplex RS232 communication interface[cite: 1].

6. Maintenance instructions

Based on the results of life tests of the 550 engine, a schedule and list of maintenance work (MOT) during the service life were developed[cite: 1].

6.1 Field maintenance (on site)

Performed by the user, has a low level of complexity[cite: 1]. Main service intervals: 50h, 100h, 250h, 350h, 400h and 500h[cite: 1]. After 500 hours of operation, the engine reaches the limit of its service life; The manufacturer's technical specialists will give a professional recommendation on the need to replace the engine[cite: 1]. The permissible deviation of maintenance time should not exceed 10 hours[cite: 1].

System	Part name	Qty	50h	100h	250h	350h	400h	500h
Ignition system	Spark plug	4	R	R	R	R	R	R[cite: 1]
	High voltage cap	4	C	C	C	C	C	C[cite: 1]
	CDI (functions, appearance)	2	C	C	C	C	C	C[cite: 1]
Cylinder block	Connecting rod lower end bearing	2	C	C	C	C	C	C[cite: 1]
	Cylinder head bolts	16	T	T	T	T	T	T[cite: 1]
	Cylinder temperature sensor	4	C	C	C	C	C	C[cite: 1]
	Generator	1	C	C	C	C	C	C[cite: 1]
	Throttle body	4	C	C	C	C	C	C[cite: 1]
Exhaust system	Exhaust pipe	4	C	C	C	C	C	C[cite: 1]
	Exhaust window gasket	4	R	R	R	R	R	R[cite: 1]
Fuel system	Bypass (hollow) bolt	4	C	C	C	C	C	C[cite: 1]
	Bypass bolt gasket	4	C	C	C	C	C	C[cite: 1]

Note: C - Check (Check, clean, replace if damaged), T - Torque (Check tightening torque), R - Replace.[cite: 1]

6.2 Factory maintenance

Performed by the manufacturer, has high complexity[cite: 1]. Main service intervals: 150h, 300h, 450h, 550h[cite: 1]. The permissible deviation of maintenance time should not exceed 10 hours[cite: 1].

System	Part name	Qty	150h	300h	450h	550h
Ignition system	Spark plug	4	R	R	R	R[cite: 1]
	High voltage cap	4	I	I	I	I[cite: 1]
	CDI (functions, appearance)	2	I	I	I	R[cite: 1]
Cylinder block	Crank mechanism	1	C	C	C	C[cite: 1]
	Main bearing	3	C	C	C	R[cite: 1]
	Front and rear crankshaft oil seals	2	C	R	C	R[cite: 1]
	Connecting rod lower end bearing	2	I	I	I	I[cite: 1]
	Cylinder block (jacket)	4	C	C	C	R[cite: 1]
	Piston	4	C	R	C	R[cite: 1]
	Piston ring	4	R	R	R	R[cite: 1]
	Piston pin retaining ring	8	R	R	R	R[cite: 1]
	Cylinder head gasket	4	R	R	R	R[cite: 1]
	Cylinder block gasket	4	R	R	R	R[cite: 1]
	Cylinder head thread	8	C	C	C	C[cite: 1]
	Engine block bolts	everything	C	R	C	R[cite: 1]
	Cylinder temperature sensor	4	I	I	I	R[cite: 1]
	Generator rotor	1	C	C	C	R[cite: 1]
	Generator stator	1	C	C	C	C[cite: 1]
	Shock absorbing cushion	4		R		R[cite: 1]
Intake system	Throttle body	4	C	C	C	R[cite: 1]
Exhaust system	Exhaust pipe	4	C	C	C	C[cite: 1]
	Exhaust window gasket	4	R	R	R	R[cite: 1]
Mounting elements	Bracket cushion	4	C	R	C	R[cite: 1]
Fuel system	Bypass (hollow) bolt gasket	4	R	R	R	R[cite: 1]
	Bypass (hollow) bolt	4	R	R	R	R[cite: 1]
	Fuel filter	1	C	R	C	R[cite: 1]

Note: I - Inspect, C - Clean, R - Replace.[cite: 1]

6.3 System warranty period

1. The warranty period for the system is 3 years. Breakdowns caused by the product itself are repaired by the manufacturer free of charge; Malfunctions caused by improper operation and damage during testing are serviced by the manufacturer for a fee[cite: 1].
2. Wearing parts and parts with a limited service life are not eligible for free service. The user must check them regularly and, if replacement is necessary, contact the manufacturer[cite: 1].