Fuel injector having after-injection reduction arrangement

• Main Authors: FOCHTMAN JAMES PAUL, WIECZOREK DAVID P
• Format: Patent
• Language: English
• Published: 10.07.2001
• Edition: 7
• Subjects: BLASTING; COMBUSTION ENGINES; HEATING; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS; LIGHTING; MECHANICAL ENGINEERING; SUPPLYING COMBUSTION ENGINES IN GENERAL, WITH COMBUSTIBLEMIXTURES OR CONSTITUENTS THEREOF; WEAPONS

The present invention provides a valve assembly including a housing, an armature, an armature bias spring, a needle, and a seat. The valve assembly housing has an inlet, an outlet, and an axially extending passageway from the inlet to the outlet along a longitudinal axis. The armature is disposed within the passageway. The armature has an armature passage including a first portion and a second portion. The first portion has a first cross-sectional area. The second portion has a second cross-sectional area. The first cross-sectional area of the first portion is greater than the second cross-sectional area of the second portion. The armature bias spring is disposed within the first portion of the armature passage. The needle is disposed within the second portion of the armature passage. The seat is located proximate the outlet. The flow restrictor is disposed between the first portion and the second portion of the armature passage of the armature. The flow restrictor includes an orifice having a third cross-sectional area that is less than the first cross-sectional area. The present invention also provides a method of generating flow from a valve assembly without after-flow through the valve assembly when the valve assembly is commanded to terminate a flow cycle. The method is achieved by sizing the first portion of the armature passage with a first volume and the second portion of the armature passage with a second volume, which is less than the first volume; providing a first vent aperture that communicates the first volume with a portion of the armature passageway; providing a second vent aperture that communicates the second volume with a portion of the armature passageway; and locating a flow restrictor between the first volume and the second volume.