초록 ▼

A fuel injector for operation with combustible gas, having a gas nozzle assembly having at least one gas nozzle opening, and at least one gas nozzle needle associated with the gas nozzle assembly and accommodated in an axial holder so that the stroke of the gas nozzle needle can be controlled. Each

A fuel injector for operation with combustible gas, having a gas nozzle assembly having at least one gas nozzle opening, and at least one gas nozzle needle associated with the gas nozzle assembly and accommodated in an axial holder so that the stroke of the gas nozzle needle can be controlled. Each gas nozzle opening leads out of the holder having a radial direction component at the nozzle end. The fuel injector has, in the holder, a needle seat upstream of the particular nozzle opening, which needle seat is provided for selectively blocking a combustible-gas flow path to the associated gas nozzle opening in interaction with the gas nozzle needle. The gas nozzle openings are distributed over part of the circumference in the circumferential direction of the gas nozzle needle. The holder, adjoining the needle seat and extending away therefrom axially in the upstream direction, is asymmetric with respect to an axial center axis through the gas nozzle needle. The asymmetry results from a cross-section expansion of the holder on a side of the holder that lies radially opposite the gas nozzle opening, such that a greater mass flow rate of combustible gas can be conducted in the holder by the crosssection expansion than on the gas nozzle opening side opposite thereto. The holder is also shaped to apply a flow direction oriented toward the radially opposite gas nozzle opening, already upstream of the needle seat and via the cross-section expansion, to a combustible-gas flow guided to the needle seat by the cross-section expansion.

대표청구항 ▼

1. A fuel injector for operation with combustible gas, comprising: at a nozzle end, a gas nozzle assembly having at least one gas nozzle opening;at least one gas nozzle needle assigned to the gas nozzle assembly and accommodated in an axial holder so that a stroke of the needle is controllable, wher

1. A fuel injector for operation with combustible gas, comprising: at a nozzle end, a gas nozzle assembly having at least one gas nozzle opening;at least one gas nozzle needle assigned to the gas nozzle assembly and accommodated in an axial holder so that a stroke of the needle is controllable, wherein each gas nozzle opening leads out of the holder at the nozzle end with a radial direction component; anda needle seat arranged in the holder upstream of the respective gas nozzle opening, the needle seat being provided for selectively blocking, in cooperation with the gas nozzle needle, a combustible gas flow path to the respective gas nozzle opening, wherein the at least one gas nozzle opening is distributed merely over part of a circumference in a circumferential direction of the gas nozzle needle, wherein the holder, adjoining the needle seat and extending axially away therefrom in an upstream direction, is formed asymmetrically with respect to an axial center axis through the gas nozzle needle, wherein the asymmetry results from a cross-section widening of the holder on a side of the holder lying radially opposite the at least one gas nozzle opening, such that the cross-section widening permits a greater mass flow of combustible gas in the holder than on a gas nozzle opening side opposite thereto, wherein the holder is also configured to apply a flow direction, oriented towards a radially opposite at least one gas nozzle opening, upstream of the needle seat and by way of the cross-section widening, to a combustible gas flow guided to the needle seat by the cross-section widening. 2. The fuel injector according to claim 1, wherein the needle seat forms a chamfered seat face which continues the cross-section widening with the applied flow direction; and/or an inlet face of the needle seat adjoining the cross-section widening aligns with an outlet face of the cross-section widening adjoining the needle seat. 3. The fuel injector according to claim 1, wherein the holder is configured to guide a combustible gas flow, which is conducted by the cross-section opening to the needle seat and over the needle seat to the at least one gas nozzle opening, along this flow path portion without stepped falls, continuously with the applied flow direction. 4. The fuel injector according to claim 1, wherein the holder is configured to guide combustible gas with the applied flow direction tangentially to the at least one gas nozzle opening. 5. The fuel injector according to claim 4, wherein the holder is configured to guide the combustible gas tangentially to an inlet end of the at least one gas nozzle opening. 6. The fuel injector according to claim 1, wherein the cross-section widening is formed as a bulge on the holder; and/or the holder forms at least one chute that guides the combustible gas flow by way of the cross-section widening to the at least one gas nozzle opening. 7. The fuel injector according to claim 1, wherein the gas nozzle needle has a nozzle-side end portion formed asymmetrically in relation to the axial center axis of the gas nozzle needle, so that the end portion causes a combustible gas flow, guided by the cross-section widening to the at least one gas nozzle opening, to be combined with a combustible gas flow on the gas nozzle opening side only immediately before the inlet end of the gas nozzle opening, and/or be guided tangentially to the gas nozzle opening; and/or the gas nozzle needle has a greater axial length adjacent to the at least one gas nozzle opening than at a side radially opposite thereto. 8. The fuel injector according to claim 1, wherein the gas nozzle needle has, on a side radially opposite the at least one gas nozzle opening, a flow-conductive molding and/or a bulge received in the cross-section widening, wherein the molding is configured to guide the combustible gas flow, guided by way of the cross-section widening, around the end portion of the gas nozzle needle in a streamlined fashion. 9. The fuel injector according to claim 1, wherein the gas nozzle needle is held in the holder so as to be secure against twisting. 10. The fuel injector according to claim 1, wherein the gas nozzle assembly has a plurality of gas nozzle openings, wherein the gas nozzle openings are distributed over part of the circumference in the circumferential direction in an angular range of 80° to 100°. 11. The fuel injector according to claim 1, wherein the gas nozzle assembly has a plurality of gas nozzle openings, wherein the gas nozzle openings are distributed over part of the circumference in the circumferential direction in an angular range of 160° to 200°. 12. The fuel injector according to claim 1, wherein the fuel injector is configured to allow a line of sight from the outlet end of the cross-section widening to an inlet cross-section of the at least one gas nozzle opening arranged radially opposite thereto upon lifting of the gas nozzle needle away from the needle seat. 13. The fuel injector according to claim 12, wherein the line of sight is from the outlet end of the cross-section widening to a lower end of the inlet cross-section of the at least one gas nozzle opening arranged radially opposite thereto. 14. The fuel injector according to claim 1, wherein the fuel injector is a dual-fuel injector that can also be operated with liquid fuel. 15. An internal combustion engine, comprising at least one fuel injector according to claim 1.