BI-FUEL ENGINE WITH VARIABLE AIR FUEL RATIO

摘要

A conventional gasoline engine is retrofitted to operate as a bi-fuel engine calibrated to burn Hydrogen gas as a primary fuel and gasoline as a secondary fuel at various acceptable air fuel ratios while avoiding forbidden air fuel ratios. The engine is preferably operated to burn Hydrogen fuel in a charged mode and in a lean mode at certain acceptable air fuel ratios where relatively very little NOx emissions occur. When additional power or acceleration is requested, processor controlled fuel injectors are operated to inject relatively small amounts of gasoline into the engine resulting in a fuel mixture that prevents increases in NOx emissions as the processor controls the engine to operate at a stoichiometric air fuel ratio where a catalytic converter is best able to reduce harmful emissions into the environment. The injection of the secondary liquid gasoline fuel to the gaseous Hydrogen fuel the temperature of the fuels significantly reduces or eliminates backfiring tendency of the engine. The engine has a safety feature in that the Hydrogen fuel is shut off if a leakage of Hydrogen is detected. The engine then operates with gasoline fuel used as a backup fuel.