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.

A fuel system is provided, comprising: a liquid fuel source; a gaseous fuel source; and a dual injector having a first flow path in flow communication with the liquid fuel source and a second flow path in flow communication with gaseous fuel source, and an outlet in flow communication with the first and second flow paths and positioned to directly inject liquid fuel from the first flow path and gaseous fuel from the second flow path into a combustion chamber of a cylinder of an engine.

A fuel system is provided, comprising: a liquid fuel source; a gaseous fuel source; and a dual injector having a first flow path in flow communication with the liquid fuel source and a second flow path in flow communication with gaseous fuel source, and an outlet in flow communication with the first and second flow paths and positioned to directly inject liquid fuel from the first flow path and gaseous fuel from the second flow path into a combustion chamber of a cylinder of an engine.

A method prevents icing of an injection system of an internal combustion engine of a motor vehicle having a high-pressure fuel pump to which, in addition to fuel, water can also be supplied via a feed line. When the motor vehicle is stopped, water still located in a wide region of the feed line is extracted, at least if required. For this purpose, a conveying device provided for conveying water to the high-pressure fuel pump is operated with the direction of rotation reversed. When the motor vehicle or the internal combustion engine is re-started, that region of the feed line from which water located therein has previously been extracted is flushed with water, the air located therein beings discharged into the surroundings.

A method prevents icing of an injection system of an internal combustion engine of a motor vehicle having a high-pressure fuel pump to which, in addition to fuel, water can also be supplied via a feed line. When the motor vehicle is stopped, water still located in a wide region of the feed line is extracted, at least if required. For this purpose, a conveying device provided for conveying water to the high-pressure fuel pump is operated with the direction of rotation reversed. When the motor vehicle or the internal combustion engine is re-started, that region of the feed line from which water located therein has previously been extracted is flushed with water, the air located therein beings discharged into the surroundings.

A dual-fuel fuel injection system for an internal combustion engine has a liquid fuel injection branch and a gas fuel injection branch, in which a gas injector assembly that is controllable via a control fluid is situated. The liquid fuel forms the control fluid of the gas injector assembly.

A dual-fuel fuel injection system for an internal combustion engine has a liquid fuel injection branch and a gas fuel injection branch, in which a gas injector assembly that is controllable via a control fluid is situated. The liquid fuel forms the control fluid of the gas injector assembly.

The subject matter of this specification can be embodied in, among other things, an apparatus that includes a high-pressure pump having a pump element, a regulating device positioned upstream of the high-pressure pump, a fuel channel defined between an inflow side of the regulating device and the pump element, and a safety device, actuatable to reduce a through-flowable cross section of the fuel channel.

A device supplies water into a high-pressure fuel pump of a motor vehicle internal combustion engine, wherein the water is admixed to the fuel in the inlet region of the high-pressure fuel pump in a controlled manner by a metering valve, and wherein the device is designed to guide the water at least from a part of a supply line back to the storage container. When viewed in the flow direction from the storage container to the high-pressure fuel pump, a shut-off valve is provided in the supply line upstream of the metering valve, and the supply line is designed to elastically deformably change its volume in a line section positioned between the valves. In an operating method, wherein, after the parking of the motor vehicle in conditions that make it possible for the liquid that is at risk of freezing to freeze, and/or after delivery of the liquid to the high-pressure fuel pump, and with a suitably adjusted upstream fluid pressure, the metering valve is opened and remains open until a portion of the fluid in the section of the supply line leading from the metering valve to the high-pressure fuel pump flows out through the metering valve.

A device supplies water into a high-pressure fuel pump of a motor vehicle internal combustion engine, wherein the water is admixed to the fuel in the inlet region of the high-pressure fuel pump in a controlled manner by a metering valve, and wherein the device is designed to guide the water at least from a part of a supply line back to the storage container. When viewed in the flow direction from the storage container to the high-pressure fuel pump, a shut-off valve is provided in the supply line upstream of the metering valve, and the supply line is designed to elastically deformably change its volume in a line section positioned between the valves. In an operating method, wherein, after the parking of the motor vehicle in conditions that make it possible for the liquid that is at risk of freezing to freeze, and/or after delivery of the liquid to the high-pressure fuel pump, and with a suitably adjusted upstream fluid pressure, the metering valve is opened and remains open until a portion of the fluid in the section of the supply line leading from the metering valve to the high-pressure fuel pump flows out through the metering valve.