Performance Requirements of Automobile Electric Fuel Pump

The automobile electric fuel pump is a vital part of the modern automotive system, it is responsible for transporting fuel from the fuel tank to the engine, ensuring its stable operation.

?

A. Components

?

There are several main parts of the automobile electric fuel pump:

?

Motor Unit

• Motor Stator: It usually consists of multiple layers of silicon steel sheets stacked together to form one or more motor slots in the motor, within which copper coils are wound. The design of the stator must take into account the uniformity of the magnetic field distribution to reduce torque ripple in the motor.
• Motor Rotor: It can be a permanent magnet rotor or a wound armature rotor. The permanent magnet rotor uses high-performance permanent magnet materials, such as neodymium iron boron (NdFeB), to provide a stable magnetic field; the armature rotor generates a magnetic field through the flow of electric current, which interacts with the stator’s magnetic field to produce torque.

?

Pump Body

• Roller-Type Pump Body: It includes cylindrical rollers and a rotor. The rollers press tightly against the inner wall of the pump body under the action of centrifugal force, forming sealed chambers to achieve the intake and delivery of fuel.
• Vane-Type Pump Body: The vanes on the rotor come into contact with the pump casing as the rotor rotates, forming sealed volumes that transport fuel from low-pressure areas to high-pressure areas.
• Gerotor Pump Body: Composed of two interlocking gears, the rotation of the gears draws fuel into the intake chamber and then compresses it in the discharge chamber, facilitating the conveyance of fuel.

?

Control Unit

The control unit receives signals from the Engine Control Unit (ECU) and adjusts the speed and flow rate of the fuel pump according to the operating state of the engine, ensuring that the fuel supply is synchronized with the engine’s demand.

?

Safety Valve

The safety valve is designed to activate when system pressure exceeds the preset value, releasing excess pressure to prevent fuel line rupture or damage to the fuel pump.

?

Check Valve

The valve ensures unidirectional fuel flow from the fuel pump to the engine, averting backflow upon pump cessation and preserving system pressure.

?

Sealing Components

Sealing Components include mechanical seals and O-rings, among others, which serve to avert fuel leakage, ensuring the pump’s sealing integrity and reliability.

?

Connectors

Connectors include the inlet and outlet fittings of the fuel pump, typically made of metal or engineering plastics, ensuring a sealed connection with the fuel lines.

?

B. Structural Features

?

• Compact Design: The electric fuel pump is designed to be compact to fit into the limited installation space of a vehicle while maintaining efficient fuel delivery capabilities.
• High Efficiency: By optimizing the motor and pump body design, such as using high-permeability magnetic materials and high-efficiency motor windings, the efficiency of fuel delivery is enhanced.
• Reliability: High-strength, corrosion-resistant materials are used, and precision machining ensures precise fitting between components, improving the durability and reliability of the fuel pump.
• Low Noise: Noise during operation is reduced by optimizing the design of the motor and pump body and using vibration-damping mounts.
• Temperature Adaptability: Materials that can adapt to a wide temperature range are selected to ensure the fuel pump can operate normally under various ambient temperatures.
• Intelligent Control: An integrated intelligent control module is used to communicate with the engine control unit, adjusting fuel supply according to real-time demands.
• Safety Features: The design includes multiple safety features such as over-heat protection and over-pressure protection to ensure the safe operation of the fuel pump under abnormal conditions.

C. Types

?

Automotive electric fuel pumps are mainly divided into the following types:

?

Roller-Type Electric Fuel Pump

1. Structure: It comprises a rotor and multiple cylindrical rollers that are housed in slots on the rotor and can slide radially.
2. Working Principle: As the rotor rotates, the rollers are forced outward by centrifugal force, creating sealed chambers with the inner wall of the pump, and facilitating the intake and compression of fuel.
3. Features: Simple structure, good sealing performance, minimal flow and pressure fluctuations, suitable for various automotive fuel systems.

?

Vane-Type Electric Fuel Pump

1. Structure: The rotor has several vanes that come into contact with the pump casing as the rotor rotates, forming sealed chambers.
2. Working Principle: The rotation of the rotor causes the vanes to slide within the casing, changing the volume of the sealed chambers, thus achieving the intake and delivery of fuel.
3. Features: Compact structure, flexible control of flow and pressure, but friction between the vanes and the casing may lead to wear.

?

Gear-Type Electric Fuel Pump

1. Structure: It consists of an internal gear and an external gear, with the internal gear typically integrated with the rotor and the external gear being part of the pump casing.
2. Working Principle: The meshing and disengagement of the internal and external gears form sealed chambers, and as the gears rotate, fuel is drawn in and expelled under pressure.
3. Features: Compact structure, high efficiency, stable flow, and pressure, but gear meshing may generate noise.

?

Diaphragm-Type Electric Fuel Pump

1. Structure: Made up of one or more flexible diaphragms, diaphragm plates, and a rotor.
2. Working Principle: The rotation of the rotor drives the diaphragm plate, causing the diaphragm to move reciprocating within the pump chamber, thus achieving the intake and discharge of fuel.
3. Features: Excellent sealing performance, no internal leakage, suitable for applications requiring high sealing integrity, but the durability of the diaphragm is crucial.

?

Screw-Type Electric Fuel Pump

1. Structure: Composed of interlocking screw rotors, usually with a single or double helix.
2. Working Principle: The rotation of the screw pushes fuel from the intake end to the discharge end, achieving continuous fuel transportation.

?

Slide-Vane Type Electric Fuel Pump

1. Structure: The rotor is equipped with one or more slide vanes, and there is a fixed pump casing around the rotor.
2. Working Principle: The slide vanes are forced outward by centrifugal force, forming sealed chambers with the casing, facilitating the intake and discharge of fuel.
3. Features: Simple structure, lower cost, but friction between the slide vanes and the casing may lead to wear.

?

Brushless DC Electric Fuel Pump

1. Structure: It utilizes brushless DC motor technology, with a rotor equipped with permanent magnets and a stator consisting of coils.
2. Working Principle: An electronic controller manages the current in the stator coils to produce a rotating magnetic field that drives the permanent magnet rotor to rotate, achieving fuel delivery.
3. Features: High efficiency, long lifespan, simple maintenance, low noise, suitable for the demanding environment of modern automobiles.

?

D. Manufacturing Process

?

1. Material Selection: Corrosion-resistant and high-strength materials are used to manufacture the pump body and rotor.
2. Precision Machining: It ensures the precise fit of the pump body and rotor to minimize leakage.
3. Electric Motor Manufacturing: High-quality windings and magnetic materials are used to ensure the performance of the electric motor.
4. Assembly Techniques: Individual components are precisely assembled to ensure the overall performance of the pump.

E. Performance Requirements

?

Flow Requirements

1. Continuous Flow: The fuel pump must provide sufficient flow to meet the engine’s fuel demands under various operating conditions.
2. Flow Stability: The flow rate should remain stable during the pump’s operation to prevent engine instability caused by flow fluctuations.

?

Pressure Requirements

1. Output Pressure: The fuel pump should deliver enough pressure to ensure fuel can overcome system resistance and reach the injectors.
2. Pressure Fluctuation: The pump should maintain stable pressure during operation to minimize the impact of pressure fluctuations on engine performance.

?

Efficiency

1. High Efficiency: The efficiency of the fuel pump directly affects the vehicle's fuel economy; a high-efficiency pump reduces energy loss.
2. Temperature Rise Control: The pump should effectively control its temperature rise during extended operation to prevent overheating.

?

Reliability and Durability

1. Long Life: The fuel pump should be designed for longevity to reduce the frequency of maintenance and replacement.
2. Wear Resistance: The rotor, stator, and sealing components of the pump should have high wear resistance to withstand long-term operation.

?

Noise and Vibration

1. Low Noise: The pump should operate at a controlled noise level to meet comfort and environmental requirements.
2. Low Vibration: The pump's design should minimize vibration to avoid affecting other vehicle components.

?

Temperature Adaptability

1. Wide Temperature Range: The fuel pump should operate normally in both extremely cold and hot environments, unaffected by temperature changes.
2. Thermal Management: The pump should have good thermal management capabilities to prevent overheating during high-temperature operation.

?

Corrosion Resistance

1. Material Selection: Materials for the fuel pump should resist corrosive substances in fuel and the environment.
2. Surface Treatment: Components of the pump may require special surface treatments, such as anodizing or coating, to enhance corrosion resistance.

?

Safety

1. Overpressure Protection: The pump should have overpressure protection mechanisms, such as a safety valve, to prevent excessive system pressure.
2. Electrical Safety: The electrical components of the pump should comply with automotive industry safety standards to prevent electrical faults.

?

Electromagnetic Compatibility

EMC Requirements: The fuel pump and its control unit should meet electromagnetic compatibility requirements to avoid interfering with other electronic systems in the vehicle.

?

Environmental Adaptability

1. Dust and Water Resistance: The pump should have certain dust and water resistance capabilities to adapt to harsh environments.
2. Chemical Resistance: The pump should resist corrosion from chemicals such as fuel additives and cleaners.

?

Intelligence and Control

1. Adjustability: The fuel pump should be able to adjust flow and pressure according to the engine's real-time demands.
2. Diagnostic Capability: The pump should have fault diagnostic capabilities for quick problem location and repair.

?

Maintenance and Service

1. Maintainability: The pump's design should consider ease of maintenance and component replacement.
2. Spare Parts Availability: Spare parts for the pump should be readily available to support quick repairs and replacements.

?

In actual design, emphasis may vary according to specific usage conditions. HONEST supports customized solutions and is committed to designing the most satisfactory solution for our customers.

?

F. Applications

The electric fuel pump system is widely applied across modern automotive systems, with the following main application areas:

1. Electronic Fuel Injection System: The electric fuel pump provides continuous and stable pressure for the fuel injection engine, ensuring that fuel is accurately injected into the engine’s combustion chamber.
2. Oil Pump: In some engine designs, the electric fuel pump can be used as an auxiliary or main oil pump, supplying the engine oil needed for lubrication and cooling.
3. Electronic Water Pump: In hybrid and electric vehicles, the electric fuel pump may be designed as an electronic water pump for cooling batteries and electric motors.
4. Automatic Transmission: The electric fuel pump supplies lubricating oil to the automatic transmission, ensuring the lubrication and cooling of gears and bearings.
5. Hydraulic Power Steering: In hydraulic power steering systems, the electric fuel pump provides hydraulic fluid, powering the steering system.

Electric fuel pumps, as indispensable power equipment in the modern industrial and automotive sectors, are characterized by their high efficiency, energy conservation, and environmental friendliness, making them a significant direction for future development. As technology continues to innovate, electric fuel pumps will unleash their potential in an increasing number of fields, contributing more to the advancement of society.