A system 10 and method of operating the system 10 are disclosed. The system 10 includes a compressor 20, a combustion engine 30, and an input system 60. The compressor 20 is configured to mix and compress a liquid hydrocarbon fuel 15 and a first hydrocarbon gas fuel 17, thereby to form a liquid fuel mixture 21. The combustion engine 30 is disposed downstream of the compressor 20 and includes a dual fuel injection system 40 and a combustion chamber 50. The dual fuel injection system 40 includes a nozzle 42 that is configured to inject the liquid fuel mixture 21 into the combustion chamber 50 of the combustion engine 30. The input system 60 is fluidly connected with the combustion engine 30, and configured to inject air 62 and a second hydrocarbon gas fuel 64 into the combustion chamber 50.

A system 10 and method of operating the system 10 are disclosed. The system 10 includes a compressor 20, a combustion engine 30, and an input system 60. The compressor 20 is configured to mix and compress a liquid hydrocarbon fuel 15 and a first hydrocarbon gas fuel 17, thereby to form a liquid fuel mixture 21. The combustion engine 30 is disposed downstream of the compressor 20 and includes a dual fuel injection system 40 and a combustion chamber 50. The dual fuel injection system 40 includes a nozzle 42 that is configured to inject the liquid fuel mixture 21 into the combustion chamber 50 of the combustion engine 30. The input system 60 is fluidly connected with the combustion engine 30, and configured to inject air 62 and a second hydrocarbon gas fuel 64 into the combustion chamber 50.

A barrel assembly for a pumping mechanism includes a first end, a second end opposite the first end, and a plunger bore configured to receive a plunger for sliding within the plunger bore. The barrel assembly also includes at least one inlet passage including at least one inlet extending through the first end and fluidly connected to the plunger bore to communicate fluid from the at least one inlet passage to the plunger bore. The barrel assembly further includes an outlet passage fluidly connected to the plunger bore and configured to receive fluid from the plunger bore, the plunger bore and the outlet passage forming separate openings in the second end of the barrel assembly.

Examples are provided for switching an engine fuel supply. One example system includes a direct-injection engine including a cylinder, an LPG tank for storing a LPG fuel, a CNG tank for storing a CNG fuel, a gas switching valve, a high-pressure pump connected between the LPG tank and the gas switching valve, a pressure-limiting valve connected between the CNG tank and the gas switching valve, a fuel distributor configured to be supplied with one or more of the LPG fuel and the CNG fuel via the gas switching valve, an LPG injection valve coupled to the cylinder, a CNG injection valve coupled to the cylinder, the LPG injection valve and the CNG injection valve configured to be supplied with fuel via the fuel distributor; and a controller configured to control the gas switching valve depending on an aggregate state of the fuel disposed in the fuel distributor.

Examples are provided for switching an engine fuel supply. One example system includes a direct-injection engine including a cylinder, an LPG tank for storing a LPG fuel, a CNG tank for storing a CNG fuel, a gas switching valve, a high-pressure pump connected between the LPG tank and the gas switching valve, a pressure-limiting valve connected between the CNG tank and the gas switching valve, a fuel distributor configured to be supplied with one or more of the LPG fuel and the CNG fuel via the gas switching valve, an LPG injection valve coupled to the cylinder, a CNG injection valve coupled to the cylinder, the LPG injection valve and the CNG injection valve configured to be supplied with fuel via the fuel distributor; and a controller configured to control the gas switching valve depending on an aggregate state of the fuel disposed in the fuel distributor.

A system 10 and method of operating the system 10 are disclosed. The system 10 includes a compressor 20, a combustion engine 30, and an input system 60. The compressor 20 is configured to mix and compress a liquid hydrocarbon fuel 15 and a first hydrocarbon gas fuel 17, thereby to form a liquid fuel mixture 21. The combustion engine 30 is disposed downstream of the compressor 20 and includes a dual fuel injection system 40 and a combustion chamber 50. The dual fuel injection system 40 includes a nozzle 42 that is configured to inject the liquid fuel mixture 21 into the combustion chamber 50 of the combustion engine 30. The input system 60 is fluidly connected with the combustion engine 30, and configured to inject air 62 and a second hydrocarbon gas fuel 64 into the combustion chamber 50.

A system 10 and method of operating the system 10 are disclosed. The system 10 includes a compressor 20, a combustion engine 30, and an input system 60. The compressor 20 is configured to mix and compress a liquid hydrocarbon fuel 15 and a first hydrocarbon gas fuel 17, thereby to form a liquid fuel mixture 21. The combustion engine 30 is disposed downstream of the compressor 20 and includes a dual fuel injection system 40 and a combustion chamber 50. The dual fuel injection system 40 includes a nozzle 42 that is configured to inject the liquid fuel mixture 21 into the combustion chamber 50 of the combustion engine 30. The input system 60 is fluidly connected with the combustion engine 30, and configured to inject air 62 and a second hydrocarbon gas fuel 64 into the combustion chamber 50.

A dual fuel system includes a first pressurized fuel reservoir, a first fuel pump fluidly connected to the first pressurized fuel reservoir, a second pressurized fuel reservoir, and a second fuel pump including a pump outlet fluidly connected to the second pressurized fuel reservoir, a pumping chamber, an actuating fluid inlet fluidly connected to at least one of the first fuel pump or the first pressurized fuel reservoir, and at least one pumping element. The first fuel pump may have excess capacity, at least at times, so as to provide a pressurized first fuel for actuating the second fuel pump. The at least one pumping element may include an intensifier or de-intensifier plunger such that a flow rate of a second pressurized fuel from the second fuel pump is different than a flow rate of the first pressurized fuel from the first fuel pump as an actuating fluid for the second fuel pump. Related apparatus and methodology is also disclosed.

A fuel injector is capable of injecting a plurality of different fuels in a single fuel injection event, the fuel injector including: a nozzle at an end of the fuel injector, the nozzle having a tip, openings in the tip of the nozzle through which fuel is configured to be injected, and a check valve member with a tip located within the nozzle, the check valve member being movable between an injection position in which fuel is injected via the openings and a closed position in which the openings are closed. The fuel injector further includes a primary fuel path within the fuel injector, a pilot fuel path within the fuel injector, and a mixing volume connecting the primary fuel path and the pilot fuel path when the check valve member is in the closed position.

An improved fuel system for a dual-fuel internal combustion engine. During normal operation, the primary fuel passes through a pressure regulator before arriving at a primary fuel rail. Further, pressurized secondary fuel is delivered to both a secondary fuel rail and to the pressure regulator for purposes of regulating the output pressure of the primary fuel that is delivered to the primary fuel rail. When the pressure at the primary fuel supply or between the primary fuel supply and the pressure regulator drops below a minimum operating pressure, the pressure regulator is isolated from the secondary fuel and the secondary fuel continues to be pressurized until it reaches a suitable pressure for operating in a limp mode. Then, the secondary fuel, which is pressurized to greater than a normal operating pressure, may be injected at the higher pressure for improved performance of the engine in the limp mode.