Dual fuel selector switch

What is this patent about?

’101 is related to the field of dual fuel internal combustion engines, specifically those used in portable electrical generators. These systems typically require the ability to switch between two distinct fuel sources, such as gasoline and liquefied petroleum gas (LPG), depending on availability or operating conditions. The background context involves the inherent safety risk of simultaneous fuel delivery, which can lead to hazardous engine conditions or improper combustion if both fuel lines are opened concurrently by an operator.

The underlying idea behind ’101 is a mechanical interlocking mechanism that physically prevents the activation of one fuel source while the other is in use. Rather than relying on complex electronic sensors or software logic, the invention utilizes a linearly translatable selector switch that acts as a physical barrier. By sliding a plate or switch body across the valve interface, the system ensures that the act of opening one fuel path automatically blocks the physical movement required to open the second path, creating a foolproof hardware-level safety constraint.

The claims of ’101 focus on a valve assembly fluidly connected to two separate fuel sources and a manual selector switch that enables the user to choose between them. The independent claims specifically highlight the use of mechanical fuel valves and handles that are operatively connected to the assembly to control flow. Furthermore, the claims describe a configuration where the selector switch is integrated with a solenoid switch to manage fuel flow, ensuring that the selection of one fuel mode actively triggers the appropriate state for the corresponding fuel solenoid.

In practice, the invention is implemented using a selector plate with two adjacent valve handles, typically oriented such that a horizontal position indicates 'OFF' and a vertical position indicates 'ON'. The sliding selector switch features a recessed channel on its rear surface that is sized to fit the handles only when they are in the horizontal position. When the switch is slid to one side, it covers one handle—locking it in the 'OFF' position—while exposing the other handle to be turned 'ON'. Once a handle is turned to the 'ON' position, its vertical orientation physically blocks the selector switch from sliding, preventing the user from switching fuels until the active valve is closed.

This approach differs from prior solutions by replacing independent, unlinked valves with a physical interlock that eliminates human error. While traditional generators might allow both a gasoline petcock and an LPG regulator to be open simultaneously, this design makes such a state mechanically impossible. Additionally, the integration of a carburetor shutoff solenoid that is triggered by the physical position of the slider ensures that the gasoline supply is electronically cut off as soon as the switch is moved toward the alternative fuel position, providing a secondary layer of automated protection.