Abstract: A method for deposit mitigation in a gaseous fuel injector that introduces a gaseous fuel through a gaseous fuel orifice directly into a combustion chamber of an internal combustion engine includes at least one of a) reducing the ago length of the gaseous fuel orifice by substantially between 10% to 50% of a previous length of a previous gaseous fuel orifice showing deposit accumulation above a predetermined threshold; b) providing the gaseous fuel orifice with an inwardly and substantially linearly tapering profile; c) determining deposit mitigation is needed; and performing at least one of the following deposit mitigation techniques i) increasing gaseous fuel injection pressure wherein deposit accumulation is reduced during fuel injection; and ii) decreasing gaseous fuel temperature wherein a rate of deposit accumulation is reduced; and d) injecting compressed air through the gaseous fuel orifice during shutdown of the internal combustion engine; whereby torque loss in the internal combustion engine due to

Abstract: A method for deposit mitigation in a gaseous fuel injector that introduces a gaseous fuel through a gaseous fuel orifice directly into a combustion chamber of an internal combustion engine includes at least one of a) reducing the ago length of the gaseous fuel orifice by substantially between 10% to 50% of a previous length of a previous gaseous fuel orifice showing deposit accumulation above a predetermined threshold; b) providing the gaseous fuel orifice with an inwardly and substantially linearly tapering profile; c) determining deposit mitigation is needed; and performing at least one of the following deposit mitigation techniques i) increasing gaseous fuel injection pressure wherein deposit accumulation is reduced during fuel injection; and ii) decreasing gaseous fuel temperature wherein a rate of deposit accumulation is reduced; and d) injecting compressed air through the gaseous fuel orifice during shutdown of the internal combustion engine; whereby torque loss in the internal combustion engine due to

Abstract: A method and apparatus for introducing gaseous fuel into a piston cylinder of an operating internal combustion engine in two separate stages involves monitoring a set of engine parameters, determining engine load and engine speed from the set of engine parameters, in a first stage, introducing a first portion of the gaseous fuel into the cylinder where the first portion of gaseous fuel forms a substantially homogeneous mixture comprising gaseous fuel and air prior to combustion, and in a second stage, occurring sequentially after the first stage, introducing a second portion of the gaseous fuel into the cylinder. The gaseous fuel quantity is variable in response to at least one of engine load and engine speed. Initiation and duration for at least one of the first and second stages is also variable in response to at least one of engine load and engine speed.

Abstract: A gaseous and liquid fuel injection valve for an internal combustion engine comprises an injection valve body that houses two separate concentric fuel injection valve assemblies. The first valve assembly is a pilot fuel needle valve assembly, which comprises a first needle movable in the direction of the longitudinal axis of the body between an open and a closed position. The second valve assembly is a gaseous fuel needle valve assembly, which comprises a second needle movable in the direction of the longitudinal axis between an open and a closed position. The gaseous fuel needle valve assembly controls the injection of gaseous fuel into the combustion chamber through a plurality of gaseous fuel holes formed in a nozzle tip of the gaseous fuel needle valve assembly. At least one of the nozzle tips is rotatable to thereby change the position of the pilot fuel holes with respect to the gaseous fuel holes.

Abstract: A method and apparatus for introducing gaseous fuel into a piston cylinder of an operating internal combustion engine in two separate stages involves monitoring a set of engine parameters, determining engine load and engine speed from the set of engine parameters, in a first stage, introducing a first portion of the gaseous fuel into the cylinder where the first portion of gaseous fuel forms a substantially homogeneous mixture comprising gaseous fuel and air prior to combustion, and in a second stage, occurring sequentially after the first stage, introducing a second portion of the gaseous fuel into the cylinder. The gaseous fuel quantity is variable in response to at least one of engine load and engine speed. Initiation and duration for at least one of the first and second stages is also variable in response to at least one of engine load and engine speed.

Abstract: Two different fuels are injected into the combustion chamber of an internal combustion engine. A main fuel is ignited by a pilot fuel that is more readily flammable than the main fuel. According to the method, load conditions on the engine are monitored and sets of conditions are defined to constitute low load conditions and high load conditions. Distinct operating modes are defined for each set of load conditions. Under low load conditions, a homogeneous mixture of main fuel and air is too lean to be flammable; consequently, the main fuel is injected at high pressure immediately following injection of the pilot fuel. Under high load conditions, fuel is injected in three stages. In the first stage, the main fuel is injected during the intake stroke or early in the compression stroke to form a substantially homogenous mixture of main fuel and air. However, the risk of knocking limits the quantity of main fuel that can be introduced in the first stage.

Abstract: This invention relates to a novel hydraulically actuated fuel injector for an internal combustion engine. More particularly, the application pertains to a hydraulically actuated gaseous injector for injecting main fuel and optional pilot fuel into an internal combustion engine at different times at controlled pressure. A hydraulically actuated fuel injector for a piston displacement engine comprising: (a) an injector which is actuated by an actuator means and injects fuel into the engine at predetermined times; (b) a means for introducing hydraulic oil into said injector; (c) means for pressurizing said hydraulic oil; (d) means for opening a fuel inlet means and injecting the fuel into the engine upon the pressure of the hydraulic oil reaching a predetermined level; and (e) a means for preventing the pressure of the hydraulic oil from rising above the predetermined level.