Engine Modification for Onboard NG Compression and Refueling

A dual mode engine cylinder that allows a single engine to both operate from and compress natural gas for onboard refueling

Background
Reciprocating internal combustion engines for passenger and commercial vehicles that are configured to operate on natural gas are commonly available. Internal combustion engines configured to operate using conventional motor fuels, such as gasoline or diesel, are also easily converted to run on natural gas. However, relatively few refueling stations exist that offer compressed natural gas for use in passenger and commercial vehicles. As a result, operators of natural gas-powered vehicles often must drive long distances to the nearest refueling station. This lack of natural gas refueling infrastructure has limited the adoption of natural gas-powered vehicles by the public and industry to those who operate on fixed routes and/or return to a central location where a refueling station can be located. Accordingly, improvements to systems and methods for refueling natural gas-powered vehicles are desirable.

Technology Description
This technology is a dual-mode engine cylinder technology that allows a single engine to function both to deliver power and compress a gaseous fuel, like natural gas. Diesel engines in particular are amenable to this design. Briefly, in ‘power-mode,’ the engine operates normally. In ‘compression mode,’ one or more of the cylinders do not combust the fuel but compress it. Without the need for separate pumping and compression infrastructure, a fleet vehicle can plug into a standard low-pressure NG line and compress it to refill an onboard tank.