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US 2014/0196687 A1Published application
In-Cylinder Dynamic Gas Blending Fuel Injector And Dual Fuel Engine
AssigneeCaterpillar Inc.
InventorsDana R. Coldren, Cory A. Brown
Life of this patent
Estimating the term…
Abstract
A dual fuel engine utilizes a compression ignited pilot injection of liquid diesel fuel to ignite a mixture of gaseous fuel and air in each engine cylinder. The gaseous fuel is injected at a relatively low pressure directly into the engine cylinder from a fuel injector. The liquid diesel fuel is injected directly into the engine cylinder from the same fuel injector. In-cylinder dynamic gas blending during the compression stroke can reduce potential hydrocarbon slip that could occur when unburned fuel resides in crevice volumes within the engine cylinder.
Claims20
A dual fuel engine comprising:
- an engine housing defining a plurality of cylinders;
- a plurality of fuel injectors, each having an injector body that defines a liquid nozzle outlet set and a gaseous nozzle outlet set that open into one of the cylinders, and defines a liquid fuel inlet, a gaseous fuel inlet and a drain outlet, and including a liquid needle valve member that opens and closes the liquid nozzle outlet set, and a gaseous needle valve member that opens and closes the gaseous nozzle outlet set, and including a first electrical actuator operably coupled to the liquid needle valve member, and a second electrical actuator operably coupled to the gaseous needle valve member;
- a high pressure liquid fuel common rail fluidly connected to the liquid fuel inlet of each of the fuel injectors;
- a low pressure gaseous fuel common rail fluidly connected to the gaseous fuel inlet of each of the fuel injectors;
- a drain line fluidly connected to the drain outlet;
- and
- each of the fuel injectors includes a drain annulus that surrounds the gaseous needle valve member, and is fluidly connected to the drain outlet.
4 more elements
A fuel injector comprising:
- an injector body that defines a liquid fuel inlet, a gaseous fuel inlet, a liquid nozzle outlet set, a gaseous nozzle outlet set and a drain outlet;
- a first electrical actuator, a second electrical actuator, a liquid nozzle chamber, a gaseous nozzle chamber, a first needle control chamber and a second needle control chamber disposed in the injector body;
- the liquid nozzle chamber, the first needle control chamber and the second needle control chamber being fluidly connected to the liquid fuel inlet;
- the gaseous nozzle chamber being fluidly connected to the gaseous fuel inlet
- a first control valve member operably coupled to the first electrical actuator and being movable between a first position that blocks the first needle control chamber to the drain outlet, and a second position that fluidly connects the first needle control chamber to the drain outlet;
- a second control valve member operably coupled to the second electrical actuator and being movable between a first position that blocks the second needle control chamber to the drain outlet, and a second position that fluidly connects the second needle control chamber to the drain outlet;
- a liquid needle valve member with an opening hydraulic surface exposed to fluid pressure in the liquid nozzle chamber, and a closing hydraulic surface exposed to fluid pressure in the first needle control chamber, and being movable between a closed position blocking the liquid nozzle chamber to the liquid nozzle outlet set, and an open position fluidly connecting the liquid nozzle chamber to the liquid nozzle outlet set;
- a gaseous needle valve member with an opening hydraulic surface exposed to fluid pressure in the liquid nozzle chamber, and a closing hydraulic surface exposed to fluid pressure in the second needle control chamber, and being movable between a closed position blocking the gaseous nozzle chamber to the gaseous nozzle outlet set, and an open position fluidly connecting the gaseous nozzle chamber to the gaseous nozzle outlet set;
- a drain annulus surrounding the gaseous needle valve member and being fluidly connected to the drain outlet.
6 more elements
A method of operating an engine, comprising the steps of:
- supplying high pressure liquid fuel to a liquid fuel inlet of a fuel injector;
- supplying low pressure gaseous fuel to a gaseous fuel inlet of the fuel injector;
- injecting gaseous fuel directly into an engine cylinder from a gaseous nozzle outlet set of the fuel injector;
- injecting liquid fuel directly into the engine cylinder from a liquid nozzle outlet set of the fuel injector;
- reducing leakage of liquid fuel into a gaseous nozzle chamber of the fuel injector by moving liquid fuel from a drain annulus that surrounds a gaseous needle valve member toward a drain outlet;
- compression igniting the injected liquid fuel in the engine cylinder;
- and
- igniting a mixture of air and the injected gaseous fuel in the engine cylinder with the compression ignited liquid fuel.
5 more elements
Dependencies are inferred from the claim text.