Abstract: This invention relates to the injection of compressible gaseous fuel directly into the combustion chamber of a reciprocating piston-type internal combustion engine. In particular, the invention provides apparatus and methods for low-pressure, high-speed direct injection of compressed natural gas into a combustion chamber of an engine. Using the present invention, relatively low intake pressures of about 50 to about 150 PSIG yield high-speed (sonic and supersonic) gas flow through the diverging nozzle portion for injection into the combustion chamber. Preferably, the gas reaches supersonic velocity, approaching Mach 1.5 to 2.5.

Abstract: This invention relates to the injection of compressible gaseous fuel directly into the combustion chamber of a reciprocating piston-type internal combustion engine. In particular, the invention provides apparatus and methods for low-pressure, high-speed direct injection of compressed natural gas into a combustion chamber of an engine. Using the present invention, relatively low intake pressures of about 50 to about 150 PSIG yield high-speed (sonic and supersonic) gas flow through the diverging nozzle portion for injection into the combustion chamber. Preferably, the gas reaches supersonic velocity, approaching Mach 1.5 to 2.5.

Abstract: Each hydrophone receiver element is attached in electrical parallel with the series combination of a switching diode and a zener diode so that the physical orientation of the element is the same for each element network. The response element networks then are assembled into a cable section, the element networks constituting a group array. A test circuit applies a relatively high dc voltage input to the cable section. The switching diodes are not rendered conductive for the elements properly connected. Hence, the output is substantially the same as the input. However, if one or more of the elements are reverse connected, the switching diode for that response element is rendered conductive and the output drops to the level of the zener breakdown voltage. Hence, the whole array-connected group can be tested with a single test.

Abstract: A marine seismic cable comprising a plurality of universal sections, each section including a plurality of fundamental arrays, preferably positioned end-to-end. Each of the arrays are separately wired to a logic circuit in one of the connectors or cans between sections and wiring is provided for connections to each of the fundamental arrays in at least an adjoining section. The logic circuits are controlled by control signals to produce composite responses from a selected grouping of fundamental arrays and, preferably, also to produce weighted or tapered responses by connecting and emphasizing each of the fundamental responses in the desired weighted manner.