This invention allows direct injection of conventional liquid fuels (e.g. kerosene or alcohol) into a combustor that is only a few centimeters in length and less than a centimeter in transverse dimension with nearly 100% energy conversion. Operation at elevated pressures is possible. The concept works with continuous or intermittent combustion.
The design allows for one gram per second or less of fuel to be vaporized mixed with the air flow and burned in a chamber about the size of a cigarette. If this is combined with a miniature compression mechanism and a miniature expansion mechanism for work extraction (e.g. turbo-machinery or piston) to form an engine with 25% or more overall thermal efficiency it is possible to deliver a kilowatt or more of power. The combustor can also be used for jet propulsion. For miniature ramjets and turbojets the combustor should achieve near 100% efficiency and allow minimal specific fuel consumption. For liquid-propellant rockets the specific impulse should compare favorably with values for the same propellants in larger rockets.