Fuel System For A Multi-Fuel Internal Combustion Engine

What is this patent about?

’120 is related to the field of multi-fuel internal combustion engines, specifically those used in generators. The background acknowledges that while gasoline is a common fuel for generators, alternative fuels like LPG offer advantages such as cleaner burning, longer storage life, and availability during gasoline shortages. Dual-fuel generators exist, but switching between fuels can cause overly rich air-fuel mixtures, especially when transitioning from liquid to gaseous fuels due to residual gasoline in the carburetor.

The underlying idea behind ’120 is to provide a system for seamlessly switching between multiple fuel sources in an internal combustion engine, minimizing disruptions and preventing overly rich fuel mixtures. This is achieved through a combination of cutoff solenoids and a control switch that precisely manages the flow of liquid and gaseous fuels to the engine's carburetor.

The claims of ’120 focus on a multi-fuel engine equipped with a carburetor, a liquid cutoff solenoid, a gaseous cutoff solenoid, and a switch to control these solenoids. Claim 1 explicitly mentions timing circuits to control the actuation time of the solenoids. Other claims cover a fuel regulator system with primary and secondary pressure regulators, and a carburetor with a cutoff solenoid that controls fuel flow through both the main and idle fuel circuits.

In practice, the system uses a combination of solenoids to control the flow of liquid and gaseous fuels. A liquid cutoff solenoid prevents fuel flow from the float bowl to the engine, while a gaseous cutoff solenoid controls the flow of gaseous fuel. A switch allows the operator to select the desired fuel, and timing circuits ensure that the solenoids are activated in a coordinated manner to prevent fuel overlap or interruption. For tri-fuel configurations, a jet block is used to couple multiple gaseous fuel sources to the carburetor, with each fuel source having its own metering jet.

This design differs from prior approaches by providing a more precise and controlled fuel switching mechanism. The use of cutoff solenoids and timing circuits allows for on-the-fly fuel switching without the engine experiencing overly rich conditions or performance interruptions. The jet block enables easy adaptation to multiple gaseous fuels, and the remote fuel regulator system simplifies integration with external fuel sources.