The fuel system is generally composed of fuel pump, fuel filter, fuel injection nozzle, etc. Its function is to ensure the fuel flow required by the engine under various working conditions.
The fuel system undertakes fuel filling and transportation, which ensures the smooth arrival of fuelengine, for engine operation.At the same time, it is responsible for collecting oil vapor and filtering it into the atmosphere.The absorption and desorption principle of the evaporation system is that the fuel oil in the oil tank generates oil vapor due to the change of ambient temperatureSteam pressureWhen the pressure is greater than the set pressure of the system, the two-way valve of the system is opened, and the oil vapor enters the carbon canister and isactivated carbon adsorption 。When the internal pressure of the system is less than the set pressure, the two-way valve opens, and the external air enters the system through the carbon canister for supplement;When the engine is running, the ECU detects that the canister purge valve is open, the canister purge valve is open, and the fuel vaporIntake manifoldUnder the action of internal negative pressure, it enters the engine to participate in combustion.
Composition and layout
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The fuel system consists of filler cap, filler pipe, fuel tank, oil pump, gasoline filter, carbon canister, carbon canister cleaning valve, pipeline and other parts.
The layout of the fuel system has an important impact on the performance of the fuel system. A reasonable layout is equivalent to adding insurance to the system. It can easily pass the national laws and regulations without any potential safety hazards.The fuel system layout roughly follows the following principles[1]：
1. Priority: After the fuel tank is arranged, priority shall be given to the arrangement of oil filter, carbon canister, solenoid valve and other components.
2. Interference: fuel system parts shall not interfere with peripheral parts, and shall meet the requirements of assembly, disassembly and inspection.
3. Thermal insulation requirements: parts of the fuel system should be as far away from heat sources such as the exhaust system as possible. If they are too close to the heat source, thermal insulation protection should be added.
Turboshaft engine
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According to the helicopter flight needsTurboshaft engineThe fuel system has the following requirements:
1. It can supply oil normally within a wide temperature range.Generally, the outside temperature range is - 60-60 ℃.If the temperature is too low, the suspended water may freeze, and the water deposited on the fuel filter will block it, reducing the fuel entering the engine and causing the engine to stop;If the temperature is too high, the fuel will also decompose to form coke under extreme heat, which will also affect the normal fuel supply of the fuel system.
2. It shall be crash resistant and bullet resistant.It is required to reduce the exposure of fuel pipes in design to prevent bullet damage;Redundancy design is adopted to ensure that the fuel system can still deliver fuel normally after some accessories are damaged;Take oil suction fuel transfer pump and crash self sealing measures to prevent fuel leakage and fire during crash.
3. Ensure good atomization quality of fuel.It is required that the fuel system can atomize the fuel evenly in the combustion chamber through the nozzle or fuel slinger in various states of the engine.
Typical specifications and standards
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Aircraft fuel systemGeneral Design Specification[2]It specifies the design, performance, compatibility and verification requirements of aircraft fuel system. The requirements and verification included in this specification are applicable to the development of military aircraft fuel system and equipment. This specification is used to guide engineering and technical personnel to design aircraft fuel system.General requirements for fuel system of civil aircraft[3]It specifies the general technical requirements and verification requirements for the function, performance design and structure of civil aircraft fuel system. This standard is applicable to the design and verification of civil aircraft fuel system.Design requirements for fuel system of civil aircraft[4]It specifies civil aircraftfuel system Airworthiness review requirements for design and verification, which are applicable to the use ofturbogeneratorCivil aircraftfuel system Design, verification and airworthiness review.
Typical patents
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Utility model patent of new fuel system[5]The utility model relates to a new type of fuel system, which is characterized in that the fuel system comprises a main box and a sub box as well as a refueling and exhaust pipe arranged between the main box and the sub box. A stainless steel pipe is also arranged between the main box and the sub box, and both ends of the stainless steel pipe are connected to the main box and the sub box respectively through a connector assembly. The overall structural design of the technical scheme is ingenious and compact,This technical solution maximizes the use of body space, meets customer requirements, and also provides more options for the future direction of automobile development.
Utility model patent of energy-saving and environment-friendly fuel system[6]It relates to an energy-saving and environment-friendly fuel system, which is characterized in that the fuel system includes ECU, engine, battery, carbon pump, lock cover and fuel tank assembly, the ECU connects the battery, engine and carbon pump through the line, the carbon pump connects the fuel tank assembly through the pipeline, the lock cover connects the fuel tank assembly through the pipeline, and the fuel system also includesSemiconductor refrigeration/The semiconductor refrigeration/heater is arranged between the battery and the carbon pump through a circuit.In this technical scheme, clean gas is discharged into the atmosphere after carbon canister adsorbs hydrocarbon, thus protecting the environment from hydrocarbon pollution;In the process of driving, the negative pressure of the bronchus generated by the engine will desorb the hydrocarbon stored in the carbon canister to the engine for combustion to generate power, saving energy and reducing costs.
Diesel locomotive fuel systemPatent related utility model[7]The diesel locomotive fuel system includes a diesel engine, a fuel tank, a fuel pump, a fuel filter and a pressure regulating deviceFuel filter, fuel pump, bypass valve, pressure regulating device and diesel engine oil inlet, the outlet of the bypass valve is connected with the fuel preheater through the bypass oil circuit, the pressure regulating device is connected with the fuel preheater through the pressure regulating oil circuit, and the fuel preheater is connected with the fuel tank through the auxiliary oil return pipeline.The patent sets bypass oil circuit and pressure regulating oil circuit in the system at the same time. The oil pressure in the system realizes two steps of initial adjustment and fine adjustment through the bypass oil circuit and pressure regulating oil circuit, which makes the system oil pressure control more accurate and ensures the reliable operation of the diesel engine.
