Abstract: An internal combustion engine may be used to compress natural gas for vehicle fuel. The engine may contain a plurality of gas compression cylinders, at least one standard combustion cylinder to drive the compression cylinders, and a common crankshaft in a crankcase coupling the compression cylinders and the at least one standard combustion cylinder. Some combustible gas being compressed may leak past the piston rings of the compression cylinders into the engine crankcase posing a safety concern. This invention eliminates this concern by actively flushing the crankcase at a higher rate than normal.

Abstract: When a natural gas compressor completes its compression cycle, residual pressurized natural gas remains in the cylinders, valves, and conduits of the compressor. Gas leaks into the environment increasing greenhouse gas emissions and introducing safety concerns. The systems and methods herein provide ways for substantially reducing or eliminating leakage of natural gas to the atmosphere while the system sits idle between compression cycles.

Abstract: Typically, an engine-compressor for compressing natural gas for use as a fuel has a single cooling circuit to cool both its combustion unit and compression unit. A single cooling circuit design is not ideal because the optimal temperature for the combustion unit is higher than the compression unit of the engine-compressor. The present invention provides a dual zone cooling system to cool the combustion unit separately from the compression unit.