How the fuel system works?

Function and Principle

The fuel system takes over the fuel filling and transportation, and it ensures that the fuel reaches the engine smoothly and is supplied to the engine to work. It is also responsible for collecting oil vapor and discharging it to the atmosphere through filtration. The principle of absorption and desorption of its evaporation system is that the fuel inside the tank produces oil vapor due to ambient temperature change. When the vapor pressure is greater than the system’s set pressure, the system’s two-way valve opens, and the oil vapor enters the carbon tank and is adsorbed by activated carbon. When the internal pressure of the system is less than the set pressure, the two-way valve opens, and the outside air enters the system through the carbon canister to replenish; when the engine is running, and the ECU detects the condition of the carbon canister cleaning valve opening, the carbon canister cleaning valve opens, and the fuel vapor enters the engine under the action of the negative pressure in the intake manifold to participate in combustion.

Composition and arrangement

The fuel system consists of a fuel cap, fuel pipe, fuel tank, fuel pump, gasoline filter, charcoal canister, charcoal canister cleaning valve, piping and other components.

The arrangement of the fuel system has an important influence on the performance of the fuel system. A reasonable arrangement is equal to adding insurance to the system, which can easily pass the national regulations without any safety hazards. The fuel system layout generally follows the following principles: 

  • 1. Priority: After the fuel tank arrangement, priority is given to the oil filter, carbon canister, solenoid valve and other parts arrangement position.
  • 2. Interference: Fuel system parts must not interfere with the surrounding parts and meet assembly, disassembly, and testing requirements.
  • 3. Heat insulation requirements: fuel system parts should be as far as possible from the exhaust system, and other heat sources, such as too close to the heat source, should add heat insulation protection.

Vortex shaft engine

According to the helicopter flight needs, the fuel system of the turboshaft engine has the following requirements.

  • 1. can be in a wide temperature range of normal fuel supply. The general requirements of the outside temperature range of -60 a 60 ℃. If the temperature is too low, the water in suspension may freeze and deposit on the fuel filter to block it, which will reduce the fuel into the engine and cause the engine to stop; if the temperature is too high, the fuel will decompose under the intense heat to form coke, which will also affect the normal fuel supply of the fuel system.
  • 2. should have the anti-crash, anti-bombing ability. Require the design to reduce the fuel pipeline exposure to prevent bullet injury; take the residual design to ensure that the fuel system can still maintain normal fuel delivery after some accessories are damaged; take the suction fuel delivery pump and crash self sealing measures to prevent the fuel from leaking and catching fire when crashing.
  • 3. Ensure good atomization quality of fuel. The fuel system must atomize the fuel evenly in the combustion chamber through the nozzle or dumping disk when the engine is in various states.

Typical specification standards

Aircraft Fuel System General Design Specification specifies the design, performance, compatibility and verification requirements for aircraft fuel systems. The requirements and verification included in the specification are applicable to the development of military aircraft fuel systems and equipment, and the specification is used to guide engineers and technicians in the design of aircraft fuel systems. Civilian aircraft fuel system general requirements specify the general technical requirements and verification requirements for the function, performance design and structure of civil aircraft fuel systems. The standard applies to the design and verification of civil aircraft fuel systems. The Civil Aircraft Fuel System Design Requirements specify the airworthiness examination requirements for designing and verifying civil aircraft fuel systems, which are applicable to the design, verification, and airworthiness examination of civil aircraft fuel systems using turbine engines.

Typical Patents

The new fuel system utility model patent relates to a new fuel system, characterized in that the fuel system includes a main tank body and a sub-tank body and a refueling and exhaust pipe set between the main tank body and the sub-tank body, and a stainless steel pipe is also set between the main tank body and the sub-tank body. The two ends of the stainless steel pipe are connected to the main tank and sub-tank bodies through the joint assembly. The overall structure of the technical solution is cleverly designed and compact, and the technical solution makes maximum use of the body space to meet the requirements of customers and also provides more selectivity for the development direction of future vehicles.

The energy-saving and environment-friendly fuel system utility model patent relates to an energy-saving and environment-friendly fuel system, characterized in that the fuel system includes ECU, engine, battery, carbon pump, lock cover and fuel tank assembly, and the ECU is connected to the battery, engine and carbon pump through the line. The carbon pump is connected to the fuel tank assembly through a line, and the lock cover is connected to the fuel tank assembly through a line. The fuel system also includes a semiconductor cooling/heater, and the semiconductor cooling/heater is set between the battery and the carbon pump through a line. The technical solution discharges clean gas into the atmosphere after adsorption of hydrocarbon by the carbon tank so that the environment is protected from hydrocarbon pollution; and the negative bronchial pressure generated by the engine during the driving of the car will desorb the hydrocarbon stored in the carbon tank to the engine combustion to generate power, saving energy and reducing costs.

The practical type of fuel system for internal combustion locomotive involves a fuel system for internal combustion locomotive, including a diesel engine, a fuel tank, a fuel pump, a fuel filter and a pressure regulating device, and the fuel tank is connected to the fuel inlet of the diesel engine through the main fuel inlet line. The fuel tank is connected to the fuel inlet of the diesel engine through the main fuel return line and also includes a bypass valve and fuel preheater. The main fuel inlet line connects the fuel tank, fuel filter, fuel pump, bypass valve, pressure regulator and the fuel inlet of the diesel engine in turn. The bypass valve outlet is connected to the fuel preheater through the bypass oil line. The pressure regulator is connected to the fuel preheater through the pressure regulator oil line, and the fuel preheater is connected to the fuel tank through the auxiliary return line. The patent sets up both the bypass oil circuit and the regulating oil circuit in the system, and the oil pressure in the system realizes two steps of initial and fine adjustment through the bypass oil circuit and the regulating oil circuit, which makes the system oil pressure control more accurate and ensures the diesel engine to work reliably.


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