Spark-ignited internal combustion engine modified for multi-fuel operation
A spark-ignited (SI) internal combustion (IC) engine designed to operate on high octane fuels, such as gasoline, is reconfigured to operate on low octane fuels including logistically preferred distillate fuels, such as diesel or JP-8. Design modifications involve coupling a fuel reformer module to the internal combustion engine. Auxiliary components include a system control module, a heat exchange module, a bypass valve to facilitate start-up, and/or a throttle body to control a reformate-oxidizer mixture fed to the engine. Small portable generators having 0.3-3.0 kWe power output are disclosed based upon the modified SI-IC engine design.
1. A method of operating a spark-ignited internal combustion engine on a low octane distillate fuel comprising:
(a) in a reformer module, contacting an oxidizer and distillate fuel having an octane rating less than 30 with a mesh or foam substrate having an ultra-short-channel length, the substrate having supported thereon a reforming catalyst; the contacting being conducted under partial oxidation reaction conditions sufficient to convert the distillate fuel into a reformate comprising hydrogen and carbon monoxide;
(b) feeding the reformate exiting the reformer into a heat exchange module wherein the reformate is in thermal conductive contact with a heat transfer fluid, so as to cool the reformate;
(c) feeding the cooled reformate and an additional supply of oxidizer into one or more reciprocating pistons of a spark-ignited internal combustion engine having one or more combustion chambers, each combustion chamber comprising said reciprocating piston and a spark igniter;
(d) co-feeding the distillate fuel having an octane number less than 30 with the cooled reformate to the one or more reciprocating pistons of the spark-ignited internal combustion engine; and combusting therein the reformate, the co-fed distillate fuel and the additional supply of oxidizer, with a spark-ignited internal combustion engine compression.
2. The method of claim 1 wherein the reformate has an octane rating greater than 80.
3. The method of claim 1 wherein the reformate comprises from 20 to less than 100 percent and wherein the co-fed distillate fuel comprises from greater than 0 to 80 percent of the total fuel fed to the engine.
4. The method of claim 1 wherein the liquid distillate fuel fed to the reformer and the liquid distillate fuel co-fed to the engine are each individually selected from the group consisting of kerosene, diesel, JP-8, JP-10, Jet-A, biodiesel, and mixtures thereof; and wherein the oxidizer fed to the reformer and the oxidizer fed to the engine are each individually selected from essentially pure oxygen, a mixture of oxygen and nitrogen, or a mixture of oxygen and an inert gas.
5. The method of claim 1 wherein mechanical energy output from the internal combustion engine is converted into electrical energy of from 0.3 to 3.0 kWe output.