Direct injection gas engine and method

摘要

The disclosure describes an engine system having liquid and gaseous fuel systems, each of which injects fuel directly into an engine cylinder. A controller monitors and controls engine operation in a normal mode, during which the engine produces rated power, and in a limp-home mode, which is used when an abnormal operating condition of the gaseous fuel system is present. During limp-home mode operation, the engine uses more liquid fuel and less or no gaseous fuel relative to the normal mode, and produces power that is less than rated power.

主权项

1. A direct injection gas engine system, comprising:
an engine having at least one cylinder that forms a variable volume between a reciprocating piston, a bore, and a flame deck; a liquid fuel system that includes a liquid fuel rail in fluid communication with a liquid fuel injector, the liquid fuel injector configured to inject liquid fuel directly into the variable volume as an ignition source; a gaseous fuel system that includes a gaseous fuel injector, the gaseous fuel injector configured to inject gaseous fuel directly into the variable volume as a power source; a controller disposed to monitor and control operation of the engine in a normal mode or in a limp-home mode, the normal mode being present when abnormal operating conditions are absent, and the limp-home mode being present when the controller determines that abnormal operating conditions are present, such that:
when operating in the normal mode, a normal amount of liquid fuel and a normal amount of gaseous fuel are injected into the cylinder to produce a rated engine power, andwhen operating in the limp-home mode, an amount of liquid fuel that is larger than the normal amount of liquid fuel and an amount of gaseous fuel that is less than the normal amount of gaseous fuel are injected into the cylinder to produce a limp-home engine power that is less than the rated power; wherein the liquid fuel system includes a liquid fuel pump configured to draw liquid fuel from a liquid fuel reservoir and provide pressurized liquid fuel to a liquid fuel rail that is fluidly connected to the liquid fuel injector, the pressurized liquid fuel being pressurized to a rail pressure; wherein the gaseous fuel system includes a cryogenic tank configured to store the gaseous fuel in a liquid state, and a gaseous fuel supply line in fluid communication with the gaseous fuel injector; wherein the gaseous fuel system further comprises a gaseous fuel pump configured to draw liquefied gaseous fuel from the cryogenic tank and provide compressed liquefied gaseous fuel to a heater, the heater configured to increase a temperature of the liquefied gaseous fuel; and a pressure control module disposed between the heater and the gaseous fuel supply line, the pressure control module configured to control a pressure of the gaseous fuel.