Applicability of LP/Natural Gas Mixture for Internal Combustion Engines

Among the natural gases proposed for use in internal combustion engines, (a) highly compressed natural gas (CNG) or (b) methane dissolved into hydrocarbon solvents (such as propane C₃H₈ or butane C₄H₁₀) are generally considered practicable. Technical problems with these that remain to be solved include low energy density of CNG ((a) above) even under very high pressure as well as significant changes in fuel composition due to the changes in the internal pressure ((b)above) of the fuel tanks as fuel is drawn.

Our research aims at developing pressurized gas mixture for internal combustion engines. In this paper, we describe our work (I) to contain fuel mixture composed of methane-rich natural gas dissolved into butane/propane-rich liquid petroleum gas (LPG): (II) to minimize changes in fuel composition due to change in the internal pressure of the fuel tank as fuel is drawn from the fuel tank, and (III) to increase the energy density of these fuel mixtures relative to the same volume of gasoline.