Vapor Vent Control for Outboard Marine Engine
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Solution Overview
Problem
Outboard marine fuel injected internal combustion engines face issues with fuel vapor and liquid fuel leaking into the air intake when the engine is removed and laid on its side or exposed to elevated thermal conditions, due to the failure of traditional float mechanisms to regulate vapor and liquid flow effectively.
Innovation Solution
A vapor vent control apparatus with a one-way valve at the fuel inlet and a movable vent pin in the vapor vent passage that automatically opens to allow vapor flow when the fuel connector is attached and closes when detached, preventing fuel vapor and liquid from entering the air intake regardless of engine orientation or thermal conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a float mechanism is used to regulate fuel vapor flow to the air intake, then fuel vapor flow is regulated during normal operation, but the float mechanism fails to function when the engine is laid on its side or exposed to elevated thermal conditions, allowing liquid fuel and vapor to leak into the air intake
Solution Approach 1:
The patent replaces the float mechanism with a magnetic field-based one-way valve system. A magnet in the fuel connector interacts with a ferromagnetic material in the vent pin, creating a magnetic force that overcomes spring pressure to open the vapor vent passage during attachment. This magnetic field-based control eliminates the need for gravity-dependent float mechanisms, ensuring reliable operation in all orientations and thermal conditions.
Solution Approach 2:
The patent changes the control parameter from gravity-dependent float position to magnetic field strength. The magnetic force generated by the magnet in the fuel connector varies with attachment status, automatically controlling the vent pin position. This parameter change enables the system to respond to attachment/detachment events without being affected by engine orientation or thermal expansion that would disrupt float-based gravity control.
2Adaptability or versatility
If the fuel connector is detached from the fuel inlet, then the engine can be removed for service or storage, but liquid fuel and fuel vapor may pass into the air intake due to gravity and pressure effects
Solution Approach 1:
The patent extracts the vapor vent control function from the continuous open passage and implements it through a controllable valve mechanism. The vent pin acts as a movable barrier that is actively controlled to close the vapor vent passage when the fuel connector is detached, preventing fuel loss while maintaining the ability to remove the engine for service or storage.
Solution Approach 2:
The system provides self-service through automatic valve actuation. The magnet in the fuel connector automatically generates the magnetic field needed to open the vapor vent passage during attachment, and the spring automatically closes it during detachment. No additional controls or manual intervention are needed, and the system adapts to attachment status changes autonomously.
3Reliability
If a one-way valve is used at the fuel inlet to prevent liquid fuel leakage, then liquid fuel is contained in the fuel system when detached, but the vapor vent passage may still allow vapor and liquid to reach the air intake
Solution Approach 1:
The patent merges the liquid fuel containment function (one-way valve at fuel inlet) with the vapor vent control function (vent pin in vapor vent passage) into a single integrated system controlled by the same magnetic field mechanism. Both the one-way valve and vent pin respond to the magnetic field generated by the fuel connector attachment, ensuring coordinated control of both liquid and vapor pathways to prevent fuel from entering the air intake.
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
The solution ensures a fluid-tight seal and prevents fuel vapor and liquid from entering the air intake during detachment or when the engine is tilted or exposed to heat, maintaining engine functionality and preventing fuel loss.
Implementation Method 1
a magnet positioned at a free end of the fuel pin. The magnet is configured to generate a magnetic field having an attractive force on a ferromagnetic material
Implementation Method 2
a spring positioned within the body in abutting relationship with the vent pin. The spring is configured to urge the vent pin in a direction opposite to the direction of the attractive force of the magnet
Data Source
Figure 1
Figure 2
Figure 2A
AI summary
An outboard marine engine has vapor vent control apparatus including a fuel inlet in fluid communication with a fuel reservoir of the engine. The fuel inlet is operably attachable to a fuel pin of a fuel connector. When attached, liquid fuel flows to the fuel reservoir and when detached, liquid fuel flow out of the fuel inlet is prevented. A vapor vent passage is configured in fluid communication with the liquid fuel reservoir and an air intake of the engine. A vent pin is disposed in the vapor vent passage. The vent pin moves between a first position upon attaching the fuel connector to the fuel inlet and a second position upon detaching the fuel connector from the fuel inlet. In the first position, the vapor vent passage is open to fuel vapor flow and, when in the second position, the vapor vent passage is closed to fuel vapor flow.