Dual fuel selector switch
Patent No. US9435273 (titled "Dual fuel selector switch") on Nov 1, 2013. The application was issued on Sep 6, 2016.
What is this patent about?
’273 is related to the field of dual fuel internal combustion engines, specifically those used in portable electrical generators. These systems typically require a safe and reliable way to switch between two distinct fuel sources, such as gasoline and liquefied petroleum gas (LPG), without the risk of mixing the two fuels within the engine’s intake system.
The underlying idea behind ’273 is a mechanical interlock system that uses a sliding physical barrier to prevent the simultaneous opening of two separate fuel valves. By utilizing a linearly translatable selector switch that physically obstructs one valve handle while exposing the other, the invention creates a foolproof hardware constraint that ensures only one fuel source can be active at any given time.
The claims of ’273 focus on a fuel selector assembly comprising two fuel valves with corresponding handles and a selector plate that supports a sliding switch. The independent claims specifically protect the configuration where the selector switch moves between two positions to selectively inhibit the actuation of one handle while allowing the other to move, thereby preventing concurrent fuel flow.
In practice, the selector switch features a rear-facing channel that captures the valve handles when they are in the closed or horizontal orientation. Because the handles cannot fit into this channel when turned to the vertical ON position, the switch acts as a mechanical lockout; a user cannot slide the switch to change fuel sources unless the currently active valve is first turned off, and once moved, the switch physically blocks the inactive handle from being turned on.
This approach differs from prior solutions that relied on separate, independent valves which could be accidentally opened at the same time. By integrating a carburetor shutoff solenoid that is triggered by the physical position of the sliding switch, the system adds an electronic layer of safety that automatically manages the carburetor's state based on the mechanical fuel selection, eliminating the possibility of operator error during fuel transitions.
How does this patent fit in bigger picture?
Technical Landscape
In the early 2010s when ’273 was filed, engine-driven electrical generators capable of dual-fuel operation were typically implemented using independent fuel delivery lines for gasoline and liquefied petroleum gas. At a time when these systems commonly relied on separate, manually operated valves to control the flow of each fuel type, the prevention of concurrent fuel delivery was often dependent on operator diligence rather than integrated mechanical safeguards. Hardware constraints in portable or small-scale power generation units made the implementation of complex electronic interlocks non-trivial, leading to architectures where two distinct fuel valves could be inadvertently placed in an open position simultaneously, creating a risk of fuel mixing within the combustion system.
Prosecution Position
The disclosed invention represents a technical advancement through a mechanical architectural shift that physically integrates the control of disparate fuel sources. By utilizing a linearly translatable selector switch coupled to a selector plate, the system creates a physical interference mechanism that prevents the concurrent actuation of two separate fuel valve assemblies. This structural solution ensures that the movement of the selector switch to a first position mechanically obstructs the second valve handle, while movement to a second position obstructs the first valve handle. The resulting technical effect is a fail-safe interlocking capability that eliminates the possibility of simultaneous fuel flow to the engine, overcoming the safety constraints inherent in systems with independent, non-communicating fuel controls.
Claims
The patent contains 19 claims, with claims 1, 9, 14, and 19 serving as the independent claims. These independent claims focus on a fuel selector mechanism and related methods for a dual fuel generator, specifically utilizing a sliding selector switch and plate assembly that physically interacts with two valve handles to ensure only one fuel source can be active at a time. The dependent claims further define the mechanical interface between the switch and handles, such as specific groove geometries and handle orientations, while also specifying fuel types like gasoline and liquid propane and incorporating electrical components like carburetor shutoff solenoids.
Key Claim Terms New
Definitions of key terms used in the patent claims.
Litigation Cases New
US Latest litigation cases involving this patent.
Patent Family
File Wrapper
The dossier documents provide a comprehensive record of the patent's prosecution history - including filings, correspondence, and decisions made by patent offices - and are crucial for understanding the patent's legal journey and any challenges it may have faced during examination.
Get instant alerts for new documents
US9435273
- Application Number
- US14069747A
- Filing Date
- Nov 1, 2013
- Publication Date
- Sep 6, 2016
- External Links
- Slate, USPTO , Google Patents