TECHNICAL FIELD

The present disclosure relates generally to a fuel flow limiter assembly in a pressurized fuel system, and more particularly to a fuel flow limiter assembly having an integrated fuel filter.

BACKGROUND

Pressurized fuel systems are well-known and widely used in internal combustion engines. In one example, a pressurized fuel reservoir is supplied with pressurized fuel from a single pump and makes the pressurized fuel available for delivery and injection into combustion cylinders in the engine by way of fuel injectors. Other pressurized fuel injection systems utilize so-called unit pumps where individual cam actuated or hydraulically actuated fuel pressurization pumps are associated with each fuel injector. Various extensions and alternatives to these two basic constructs have been proposed over the years.

In recent years the desirability of ever higher fuel injection pressures has been widely recognized. High fuel pressures can enable tiny amounts of fuel to be injected rapidly and precisely, and provide improved atomization and other properties to mitigate certain undesired emissions.

Such systems tend to be highly sensitive to debris, however, as small particles present in fuel supplied into the system, or produced by components in the system itself, can interfere with the motion of rapidly moving fuel injector and pump components or otherwise cause performance degradation. Engineers have experimented for many years with different strategies for filtering fuel to remove particles, including systems where all of the fuel is filtered upstream of a pressurized fuel reservoir, and also systems where fuel is filtered between a pressurized fuel reservoir and individual fuel injectors. One example pressurized fuel system employing fuel filtration between a pressurized fuel reservoir and a fuel injector is set forth in United States Patent Application Publication No. 20150345448A1 to Gerstner et al. While the strategy set forth in the '448 application may have certain advantages and applications, there is always room for improvement and development of alternative strategies.

SUMMARY OF THE INVENTION

In one aspect, a fuel flow limiter assembly includes a limiter body defining a longitudinal axis extending between a first axial body end and a second axial body end, and including an axially extending central bore, and a fuel inlet formed in the first axial body end and fluidly connected to the central bore. The limiter assembly further includes a connector coupled to the second axial body end, and including a fuel outlet fluidly connected to the central bore. The limiter assembly further includes a shutoff piston within the central bore and including a closing hydraulic surface exposed to a fluid pressure of the fuel inlet, and a sealing surface. The shutoff piston is movable within the central bore in a direction of the second axial body end from an open position, to a closed position where the sealing surface is in contact with the connector to block fuel flow from the fuel inlet to the fuel outlet. The limiter assembly further includes a biasing spring trapped between the shutoff piston and the connector and biasing the shutoff piston toward the open position, and a fuel filter supported in the connector. The fuel filter projects from the connector in the direction of the first axial body end in a fuel flow path from the fuel inlet to the fuel outlet.

In another aspect, a fuel system for an internal combustion engine includes a pressurized fuel reservoir, a plurality of fuel injectors fluidly connected to the pressurized fuel reservoir, and a plurality of flow limiter assemblies each positioned fluidly between the pressurized fuel reservoir and at least one of the plurality of fuel injectors. Each of the plurality of flow limiter assemblies defines a longitudinal axis and includes a fuel inlet, a fuel outlet, a central bore, a biasing spring, and a shutoff piston positioned in the central bore, and movable in opposition to a bias of the biasing spring to a closed position based on a fuel pressure drop from the fuel inlet to the fuel outlet. Each of the plurality of flow limiter assemblies further includes a fuel filter having a filter inlet surface exposed to a flow of fuel in the central bore, and a filter outlet surface forming a filtered fuel passage extending to the fuel outlet, in the respective flow limiter assembly.

In still another aspect, a fuel feed subsystem for a fuel injector includes a leakage containment housing structured to couple with a pressurized fuel reservoir, and a fuel flow limiter assembly within the leakage containment housing. The fuel flow limiter assembly includes a limiter body defining a longitudinal axis, and a connector coupled to the limiter body. The limiter body has a fuel inlet formed therein and an axially extending central bore fluidly connected to the fuel inlet. The connector has a fuel outlet formed therein and fluidly connected to the central bore. The fuel flow limiter assembly further includes a biasing spring, and a shutoff piston including a closing hydraulic surface exposed to a fluid pressure of the fuel inlet, and a sealing surface. The shutoff piston is movable within the central bore in opposition to a biasing force of the biasing spring from an open position to a closed position to block fuel flow from the fuel inlet to the fuel outlet. The subsystem further includes a fuel filter resident in the fuel flow limiter assembly and supported in the connector such that the fuel filter projects from the connector in an upstream direction relative to a fuel flow path from the fuel inlet to the fuel outlet.

