Ejector Fuel Recirculation Line for Vapor Control
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Solution Overview
Problem
Existing vehicle fuel systems face challenges in reducing air entrainment and further vaporization of fuel during refueling, leading to inefficiencies and potential increases in emissions.
Innovation Solution
A fuel system with a recirculation line connected to the fuel fill inlet and fuel tank, featuring an ejector that maintains a check valve in a closed position using suction, preventing fluid flow and reducing vapor generation by recirculating vapor back through the fill inlet during refueling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a recirculation line is added to reduce air entrainment and vaporization, then fueling efficiency is improved, but device complexity increases
Solution Approach 1:
The ejector utilizes the kinetic energy of liquid fuel flowing through the recirculation line to generate vacuum suction automatically, without requiring an external power source or control system. The liquid fuel's own flow energy is converted into vacuum pressure to draw vapors back through the recirculation line, making the system self-regulating and eliminating the need for additional actuators or power consumption.
Solution Approach 2:
The ejector employs hydraulic principles by using the flowing liquid fuel as a motive fluid to create a vacuum effect. The liquid fuel's pressure and velocity are converted into suction force through the ejector's nozzle design, demonstrating hydraulic energy conversion to achieve vapor recirculation without mechanical moving parts.
2Reliability
If an ejector is used to maintain check valve closure, then vapor recirculation is improved, but device complexity increases
Solution Approach 1:
The ejector automatically generates vacuum suction based on the natural flow of liquid fuel through the recirculation line. This self-activating mechanism maintains check valve closure during fueling without requiring external sensors, controllers, or additional actuators, thereby improving reliability while avoiding increased component complexity.
Solution Approach 2:
The ejector replaces complex mechanical valve actuation systems with a fluid-dynamic solution. Instead of using motors, solenoids, or complex linkage mechanisms to control the check valve, the system uses the ejector's hydraulic vacuum effect to maintain valve closure, simplifying the mechanical complexity while improving control reliability.
3Object-generated harmful factors
If vapor recirculation is implemented, then emissions are reduced, but energy loss increases
Solution Approach 1:
The system converts the potentially harmful effect of liquid fuel flow (which could cause air entrainment and vaporization) into a beneficial vacuum-generating force. The kinetic energy of the liquid fuel is transformed by the ejector into suction pressure that recirculates vapors, turning what could be a source of emissions into the driving mechanism for emission reduction.
Solution Approach 2:
Instead of discarding fuel vapors to the atmosphere through the fuel fill inlet, the system recovers them by recirculating them back into the fuel tank through the recirculation line. The ejector enables this recovery process by generating the necessary vacuum to draw vapors from the fill inlet and return them to the tank, preventing emissions while recovering valuable fuel vapor.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution effectively reduces air entrainment and vaporization within the fuel tank, enhancing fueling efficiency and potentially minimizing the size of the evaporative emissions system components.
Implementation Method 1
The ejector draws suction on the check valve to maintain the check valve in a closed position in response to vapor flow through the recirculation line and ejector during fueling of the fuel tank
Implementation Method 2
Vapor is recirculated from the fuel tank to the fuel fill inlet via a recirculation line with an ejector in response to the liquid fuel being dispensed
Data Source
AI summary
A vehicle and a fuel system for a vehicle are provided. The fuel system has a fuel tank, a fuel fill inlet fluidly connected to the fuel tank to receive fuel dispensed from an external fuel supply device, and a recirculation line with a first end fluidly connected to the fuel fill inlet and a second end fluidly connected to the fuel tank. An ejector is positioned within the recirculation line. A valve fluidly connects the ejector to the fuel tank via a drain line. A method of fueling a vehicle is also provided.