Fuel supply device for gas engine

What is this patent about?

’479 is related to the field of fuel delivery systems for internal combustion engines, specifically those designed to operate on multiple types of gaseous fuels. In many industrial or portable engine applications, there is a need to switch between different fuel sources, such as butane from a small cylinder and propane from a larger tank, each requiring specific pressure regulation and vaporization stages before entering the engine's intake system.

The underlying idea behind ’479 is the elimination of external plumbing and discrete mounting brackets by integrating all gas-handling components into a single, modular unit. Rather than connecting a vaporizer, multiple regulators, and selector valves via a complex web of hoses and fittings, the invention utilizes direct, bolt-on connections between functional blocks. This architecture reduces the overall footprint, minimizes potential leak points, and allows the same core components to be rearranged for different engine configurations.

The claims of ’479 focus on a unified fuel supply assembly that integrates a vaporizer, a primary regulator, a fuel changeover valve, a cutoff valve, and a secondary regulator into a single physical unit. The system is designed to process a first fuel through a dedicated vaporization and high-pressure regulation stage while allowing a second, already-gaseous fuel to bypass those stages. Both fuel paths eventually converge at a common secondary regulator that brings the selected fuel to atmospheric pressure for delivery to the engine mixer.

In practice, the device functions as a multi-stage pressure reduction gallery. When the first fuel is selected, it is heated and gasified, stepped down in pressure by the primary regulator, and then passed through the changeover valve. The cutoff valve acts as a safety gate, only allowing fuel to reach the final secondary regulator when it senses engine vacuum, indicating the engine is actually cranking or running. This ensures that fuel flow is strictly tied to engine demand regardless of which source is active.

This approach differs from prior art by utilizing a detachable modular interface that allows for high manufacturing flexibility. By standardizing the connecting parts between the modules, a manufacturer can easily produce a dual-fuel changeover system, a butane-only system, or a propane-only system using the same basic components. This modularity bypasses the need for custom piping layouts for every engine variant, significantly reducing assembly labor and material costs while improving reliability through integrated fuel passages.