A plunger of a high-pressure pump is provided reciprocatably on an inner side of a cylinder. A holder disposed on an opposite side of the cylinder from a pressurizing chamber includes a large tubular portion that provides a predetermined space between the large tubular portion and an outer wall of the plunger, and a small tubular portion that is disposed on an opposite side of the large tubular portion from the cylinder. A pin inserted into a hole of the plunger at a position corresponding to the large tubular portion protrudes radially outward from the outer wall of the plunger and is accommodated in a space on an inner side of the large tubular portion.

A fuel supply valve for a slurry fuel injector valve comprises a fuel inlet in fluid communication with a slurry fuel reservoir. A fuel outlet is in fluid communication with a nozzle of the fuel injector valve. A pump chamber port is in fluid communication with a pump chamber of the fuel injector valve. A valve gate is moveable between a first position wherein the fuel inlet is in fluid communication along a first slurry fuel flow path with the pump chamber port and a second position wherein the fuel outlet is in fluid communication along a second slurry fuel flow path with the pump chamber port. Wherein the valve gate is arranged to not substantially exert a force opposing a flow on the slurry fuel into the valve chamber when the valve gate moves between the second position and the first position and/or between the first position and the second position.

Disclosed is a valve needle for a needle valve of a slurry fuel injector valve, the valve needle comprising: a tip for abutting a needle valve seat of the needle valve; a sealing portion for location in a bore of the needle valve; and a fuel chamber portion between the tip and the sealing portion, wherein the fuel chamber portion is for location in a needle fuel chamber of the needle valve; wherein a surface of the sealing portion of the valve needle comprises at least one groove and wherein at least part of the or each groove extends in a direction that is non-perpendicular to an axial direction of the valve needle.

The present invention relates to a fuel injection arrangement for a diesel type engine configured to use carbonaceous aqueous slurry fuels. The fuel injection arrangement includes an injector nozzle for injecting fuel into a combustion chamber; a pump chamber housing a fuel pumping element for generating a pressurised fuel flow to the injector nozzle along an injection path between the pumping element and the injector nozzle; and a check valve connected to a fuel supply for regulating and supplying fuel to the injection path via a check valve outlet. A region immediately downstream of the check valve outlet defines an outlet region and the check valve is arranged to expose the outlet region to the pressurised fuel flow to facilitate flushing of the outlet region during fuel flow between the pumping element and the injector nozzle.

A high-pressure fuel pump includes a housing including a chamber, an inlet flow passage to draw fuel into the chamber, and a discharge flow passage to discharge fuel out of the chamber. The high-pressure fuel pump further includes a piston disposed in the housing and configured to compress fuel, a sleeve coupled to the housing and configured to support the piston and form a space for storing fuel, a discharge valve disposed in the discharge flow passage and configured to open when a pressure of fuel stored in the chamber is equal to or greater than a first pressure, and a pressure relief valve disposed in a relief flow passage that communicates with the discharge flow passage and the space. The pressure relief valve is configured to open when a pressure of fuel supplied into the relief flow passage is equal to or greater than a second pressure.

A fuel supply valve for a slurry fuel injector valve, the fuel supply valve comprising: a fuel inlet for fluid communication with a slurry fuel reservoir; a fuel outlet for fluid communication with a nozzle of the fuel injector valve; a pump chamber port for fluid communication with a pump chamber of the fuel injector valve; and a valve gate moveable between a first position, at which the fuel inlet is in fluid communication along a first slurry fuel flow path with the pump chamber port, and a second position, at which the fuel outlet is in fluid communication along a second slurry fuel flow path with the pump chamber port; wherein the valve gate is operable with a valve actuation liquid from an engine.

Disclosed is a slurry fuel injector valve, comprising: a fuel outlet valve through which slurry fuel is able to exit the slurry fuel injector valve towards a combustion chamber of an engine; a pump cavity; a pump element that divides the pump cavity into a pump chamber and an actuation chamber; a fuel conduit through which slurry fuel is flowable from the pump chamber to the fuel outlet valve; and an actuation fluid conduit through which actuation fluid is flowable from the actuation chamber to the fuel outlet valve.

A fuel supply valve for a slurry fuel injector valve, the fuel supply valve comprising: a fuel inlet for fluid communication with a slurry fuel reservoir; a fuel outlet for fluid communication with a nozzle of the fuel injector valve; a pump chamber port for fluid communication with a pump chamber of the fuel injector valve; and a valve gate moveable between a first position, at which the fuel inlet is in fluid communication along a first slurry fuel flow path with the pump chamber port, and a second position, at which the fuel outlet is in fluid communication along a second slurry fuel flow path with the pump chamber port; wherein the valve gate is operable with a valve actuation liquid from an engine.

Disclosed is a slurry fuel injector valve, comprising: a fuel outlet valve through which slurry fuel is able to exit the slurry fuel injector valve towards a combustion chamber of an engine; a pump cavity; a pump element that divides the pump cavity into a pump chamber and an actuation chamber; a fuel conduit through which slurry fuel is flowable from the pump chamber to the fuel outlet valve; and an actuation fluid conduit through which actuation fluid is flowable from the actuation chamber to the fuel outlet valve.

Disclosed is a valve needle for a needle valve of a slurry fuel injector valve, the valve needle comprising: a tip for abutting a needle valve seat of the needle valve; a sealing portion for location in a bore of the needle valve; and a fuel chamber portion between the tip and the sealing portion, wherein the fuel chamber portion is for location in a needle fuel chamber of the needle valve; wherein a surface of the sealing portion of the valve needle comprises at least one groove and wherein at least part of the or each groove extends in a direction that is non-perpendicular to an axial direction of the valve needle.