BI-FUEL LIQUID INJECTION SYSTEM FOR AN INTERNAL COMBUSTION ENGINE

摘要

A bi-fuel injection system includes a source of first liquid fuel; a source of second liquid fuel; at least one fuel injector (30); a common fuel rail (32) for supplying first or second fuels to the fuel injector; a first valve structure (34) in selective communication with the source of first or second fuels and in communication with an inlet of the fuel rail to selectively control supply of one of the first and second fuels to the fuel rail; and a second valve structure (38) in communication with an outlet of the fuel rail and in selective communication with the source of the first or second fuels to return fuel exiting the fuel rail to the source of the first and second fuels. The second valve structure (38) may be in selective communication with a vapor purge system to receive fuel vapors exiting the fuel rail. The first and second valve structures are selectively controllable (1) to permit residual first fuel to be purged from the rail into one of the sources of first and second fuels when supplying the second fuel to the fuel rail, and (2) to permit residual second fuel to be purged from the fuel rail into the vapor purge system or one of the sources of first and second fuels when supplying the first fuel to the fuel rail.