A fuel injector is provided which has a valve member, a valve member guide and a spring chamber. Discharge of fuel out of a fuel injector outlet is controlled by movement of the valve member within a bore of the valve member guide. The spring chamber contains a biasing member, which is a compression spring, and which biases the valve member into contact with a valve seat when in a closed configuration. The fuel supply passage is provided, which by-passes the spring chamber, to direct a flow of the fuel to an outlet chamber of the fuel injector, and the cleaning fluid supply passage is provided to supply a pressurized cleaning fluid to a second end of the bore to restrict leakage of the fuel from the outlet chamber towards the second end of the bore along a clearance extending between the valve member and the valve member guide.

A controller for controlling a fuel injection valve and a fuel pressure adjustment mechanism integrates a deposition amount of deposits per unit time, and estimates a deposition amount of deposits on an injection hole of the fuel injection valve. The controller causes the fuel pressure adjustment mechanism to increase a fuel pressure, when the estimated deposition amount exceeds a predetermined value, and corrects the unit deposition amount acquired by the deposition amount estimation according to the set fuel injection timing of the fuel injection valve. The controller corrects such that as compared with the unit deposition amount when the fuel injection timing is set to a first timing away from a top dead center of the piston by a first period, the unit deposition amount decreases when the fuel injection timing is set to a second timing away by a second period longer than the first period.

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 deposit accumulation in the gaseous fuel orifice is reduced below a predetermined value.

A method for fouling an injector of a gasoline direct injection engine, includes the steps of operating the direct injection engine on at least a first stationary engine mode which is defined by a pre-established engine load and a pre-established engine speed. Both the pre-established engine load and the speed are within 35% and 65% of their maximum values, this at least first stationary engine mode being characterized by high particulate matter generation. The direct injection engine is operated on the at least first engine mode for less than ten hours.

A method for evaluating the fouling effect of a gasoline formulation in a gasoline direct injection engine uses the above-described fouling method.

A fuel injection apparatus for injecting fuel to an engine having cylinders, includes: injectors corresponding to the cylinders; a regulator for fuel pressure supplied to the injectors; and a processor. The processor performs: deciding to start a deposit removal for removing deposits adhering to injector-nozzles; and controlling each injector to inject fuel in a single injection mode for injecting one time or a divided injection mode for injecting multiple times in one combustion cycle and control the regulator based on engine operation condition. The controlling includes, when controlling each injector to inject fuel in the divided injection mode based on the engine operation condition, sequentially controlling each injector to reduce injection number in one combustion cycle when the deposit removal is decided to be started, and then controlling the regulator to increase fuel pressure.

A fuel injector cleaning system includes an injector cleaning housing that defines a cavity structured to receive a fuel injector. A heater is operatively coupled to the housing. A three-way valve includes a first inlet fluidly coupled to a calibration fluid reservoir, and a second inlet fluidly coupled to a cleaning fluid reservoir. An intake line includes a first end fluidly coupled to an outlet of the valve, and a second end structured to be fluidly coupled to a fuel inlet of the fuel injector. A controller is operatively coupled to each of the heater and the valve. The controller is structured to actuate the valve so as to cause flow of a cleaning fluid to the fuel injector. The heater is operated so as to heat the cleaning fluid. The valve is actuated so as to cause flow of a calibration fluid to the fuel injector.

A fuel injector cleaning system includes an injector cleaning housing that defines a cavity structured to receive a fuel injector. A heater is operatively coupled to the housing. A three-way valve includes a first inlet fluidly coupled to a calibration fluid reservoir, and a second inlet fluidly coupled to a cleaning fluid reservoir. An intake line includes a first end fluidly coupled to an outlet of the valve, and a second end structured to be fluidly coupled to a fuel inlet of the fuel injector. A controller is operatively coupled to each of the heater and the valve. The controller is structured to actuate the valve so as to cause flow of a cleaning fluid to the fuel injector. The heater is operated so as to heat the cleaning fluid. The valve is actuated so as to cause flow of a calibration fluid to the fuel injector.

Ethylene-C.sub.3-C.sub.10 alpha olefin copolymers, dispersants and lubricating oils/fuel compositions incorporating dispersants, and related methods are generally described herein. The copolymer may comprise ethylene-derived units and C.sub.3-C.sub.10 alpha-olefin-derived units. The C.sub.3-C.sub.10 alpha-olefin-derived units may have a carbon number from three to ten. For example, the C.sub.3-C.sub.10 alpha-olefin-derived units may be propylene-derived units.

An injector testing system includes a testing rig having a receptacle and an injector mounting structure. The receptacle has an inlet for receiving fluid injected by an injector, a target outlet for receiving at least a portion of fluid injected through the inlet, and a runoff outlet for receiving fluid missing the target outlet. At least one fluid-quantity measuring device fluidly connected to at least one of the target and runoff outlets measures a quantity of fluid having flowed thereto. A controller receives signals representative of (i) a quantity of fluid having flowed to the at least one fluid-quantity measuring device via the target outlet, and (ii) a quantity of fluid having flowed to the at least one fluid-quantity measuring device via the runoff outlet or both of the runoff outlet and the target outlet. Based on these quantities, a proportion of fluid injected into the target outlet is determined.

Systems and methods provide for cleaning the air intake valves and surrounding areas of an engine. A gravity-fed cleaning-fluid dispenser may feed cleaning fluid into a hose through a metered device that meters a rate at which the cleaning fluid flows into the hose. A second fluid meter connected to a distal end of the hose further meters the rate at which a mixture of the cleaning fluid and air from is dispersed into the running GDI engine. Cleaning fluid may be distributed to the engine at a gradually decreasing rate as a volume of cleaning fluid in the dispenser decreases as the service progresses.