Patent ID: 8226018
Filing Date: 2012-07-24
Classification: F02M

Abstract:
1. A fuel injector comprising an injector housing containing a nozzle needle movable between open and closed positions, a coupling chamber having a pressure therein, a pressure chamber, and a high-pressure fuel connection that is connected to a central high-pressure fuel source outside the injector housing and to the pressure chamber inside the injector housing, and depending on the pressure within the coupling chamber, highly pressurized fuel is injected from the pressure chamber into a combustion chamber of an internal combustion engine when the nozzle needle moves to its open position, wherein the nozzle needle has an end oriented away from the combustion chamber, which end has a pressure surface that is acted on by the pressure in the coupling chamber, and at least one low-pressure surface oriented away from the combustion chamber that is acted on by low pressure, wherein the end of the nozzle needle further has two guide sections of different diameters connected to each other by a shoulder, wherein the shoulder constitutes the low-pressure surface acted on by low pressure, and wherein the end of the nozzle needle oriented away from the combustion chamber is guided with the two guide sections in a double guide body situated in a high-pressure chamber between the injector housing and the end of the nozzle needle.