Injector having swirl structure downstream of valve seat

Abstract

An atomizing injector comprises a body having a central bore with a valve situated in the bore, leading to a chamber. An actuator moves the valve between closed condition and open conditions, selectively exposing the chamber to a flow of pressurized liquid. A discharge port extends from the chamber to a discharge orifice. A swirl element is situated in the chamber, while leaving a free space in the chamber immediately above the discharge port. When the valve is opened, liquid flows into the chamber, through the swirl element into the space, forming a whirl in the space before passing through the discharge port and exiting the discharge orifice as an atomized whirling spray.

1 . An injector comprising:
 a longitudinal body;   a central bore in the body, having upper and lower ends and a source volume for receiving pressurized fluid to be injected;   a valve situated in the bore, having a moveable sealing face selectively seated against a stationary sealing face;   a chamber in selective fluid communication with the source volume through said valve;   a control system that selectively moves the valve member into a closed condition whereby said moveable face seals against said stationary face and into an open condition whereby the moveable face lifts from said stationary face;   a discharge port from the chamber to a discharge orifice;   a swirl element situated in the chamber, while leaving a free space in the chamber immediately above the discharge port; and   whereby when the valve is in said closed condition, no fluid can enter said chamber from the source volume and when the valve is in said open condition, pressurized fluid flows into said chamber, through said swirl element into said space, forming a whirl in said space before passing through said discharge port and exiting said discharge orifice as an atomized whirling spray.   
     
     
         2 . The injector of  claim 1 , wherein the valve includes a moveable valve member and the swirl element is an integral extension on said valve member, which remains in the chamber during both closing and opening of the valve. 
     
     
         3 . The injector of  claim 1 , wherein said chamber is substantially cylindrical and the swirl element is a substantially solid cylinder having an external diameter closely conforming to the diameter of said chamber, with a single or multiple external helical groove(s), such that substantially all flow to the discharge port in the valve open condition, first passes through said grooves. 
     
     
         4 . The injector of  claim 2 , wherein the chamber is substantially cylindrical and the swirl element is a solid member having a single or multiple external helical groove(s) that closely conforms to the chamber, such that substantially all flow to the discharge port in the valve open condition, first passes through said grooves. 
     
     
         5 . The injector of  claim 1 , wherein
 said chamber has a substantially cylindrical wall;   a solid cylindrical plug in said chamber has an external diameter closely conforming to the diameter of said wall;   said swirl element includes single or multiple external helical groove(s) in said wall, confronting the plug;   whereby substantially all flow to the discharge port in the valve open condition, first passes through said grooves.   
     
     
         6 . The injector of  claim 5 , wherein the plug is a unitary part that is fixed within the chamber. 
     
     
         7 . The injector of  claim 1 , wherein said moveable sealing face and stationary sealing face are distinct components within the body. 
     
     
         8 . The injector of  claim 7 , wherein
 the body has upper and lower ends;   the bore passes through the lower end of the body; and   said discharge port and discharge orifice are provided in a platform fixed with respect to the bore and situated immediately downstream of the component having the stationary sealing face.   
     
     
         9 . The injector of  claim 8 , wherein the component having the stationary sealing face and the platform are integral. 
     
     
         10 . The injector of  claim 9 , wherein the swirl element is a solid member having a single or multiple external helical groove(s) that closely conforms to the chamber, such that substantially all flow to the discharge port in the valve open condition, first passes through said grooves. 
     
     
         11 . The injector of  claim 1 , wherein the injector is mounted on an exhaust pipe of a diesel engine. 
     
     
         12 . An injector for intermittently delivering an atomized spray from a source of pressurized liquid, comprising:
 a body having a central bore and upper and lower ends, the lower end having a substantially conical internal sealing face;   a needle valve situated in the bore, having a tapered nose juxtaposed with and sealable against said face;   a liquid inlet to the bore in fluid communication with the face;   an actuator that selectively moves the valve downwardly into a closed condition whereby said nose seals against said face and upwardly into an open condition whereby the nose lifts from said face and liquid flows past said face;   swirl means downstream of the face, including a groove pattern associated with a plug element for producing a helical flow confined in the grooves around the plug element;   a free space downstream of the plug element, in which liquid exiting the grooves consolidates as a swirl; and   a narrow, axially extending passage having an associated discharge orifice, providing the only exit for the liquid from the free space.   
     
     
         13 . The injector of  claim 12 , wherein the swirl element remains in the chamber during both closing and opening of the valve. 
     
     
         14 . The injector of  claim 13 , wherein the swirl element is a substantially solid cylinder with a single or multiple external helical groove(s). 
     
     
         15 . An injector mounted on an exhaust conduit from a diesel engine and supplied with a source of exhaust treatment liquid comprising:
 a longitudinal body having a central bore and upper and lower ends, the lower end having a substantially conical internal face narrowing to a chamber;   a needle valve situated in the bore, having a tapered nose juxtaposed with the conical face of the body;   a control system that selectively moves the valve downwardly into a closed condition whereby the nose seals against a seat on the face and upwardly into an open condition whereby the nose lifts from the seat;   a swirl element below the seat; and   a passage for supplying said exhaust treatment liquid to the face upstream of the seat;   whereby when the valve nose is seated in the closed condition, no liquid can enter the chamber and when the valve nose is lifted off the face, liquid flows through the swirl element into a space in the chamber, forming a whirl in the space before exiting through a discharge orifice as an atomized whirling spray.   
     
     
         16 . The injector of  claim 15 , wherein the swirl element remains in the chamber during both closing and opening of the valve. 
     
     
         17 . In an injector mounted on a vehicle exhaust pipe, said injector having a body, a pressurized volume of treatment liquid within the body, and means operatively associated with the body for discharging the pressurized liquid into the exhaust pipe as an atomized swirl, the improvement to the means for discharging the pressurized liquid comprising:
 a chamber in fluid communication with said pressurized volume of treatment liquid;   a valve between said chamber and said pressurized volume of treatment liquid;   a discharge port from the chamber to a discharge orifice;   a swirl element situated in the chamber, while leaving a substantially cylindrical free space immediately above the discharge port;   whereby when the valve is closed, no fluid can enter said chamber and when the valve is open, pressurized fluid flows into said chamber, through said swirl element into said space, forming a whirl in said space before passing through said discharge port and exiting said discharge orifice as an atomized whirling spray.   
     
     
         18 . The injector of  claim 17 , wherein the chamber is substantially cylindrical, the swirl element is fixed within the chamber, and the swirl element has at least one flow channel leading to said space. 
     
     
         19 . The injector of  claim 18 , wherein the swirl element comprises a substantially cylindrical plug and the at least one flow channel is an external single or multiple helical groove(s) on the plug. 
     
     
         20 . The injector of  claim 17 , wherein the swirl element comprises a substantially cylindrical plug with upper and lower ends and the at least one flow channel is a plurality of slots at the lower end of the plug. 
     
     
         21 . The injector of  claim 17 , wherein the swirl element comprises a substantially cylindrical plug with upper and lower ends and a flat disc at the lower end of the plug, said at least one flow channel provided as a plurality of slots in said disc. 
     
     
         22 . The injector of  claim 17 , wherein the swirl element comprises a substantially cylindrical plug with upper and lower ends and the at least one flow channel is a plurality of bores through the plug. 
     
     
         23 . The injector of  claim 18 , wherein said swirl element has upper and lower ends, the chamber has a bottom, and said space is situated between the lower end of the swirl element and the bottom of the chamber. 
     
     
         24 . The injector of  claim 21 , wherein the chamber has a bottom, said disc is trapped between the plug and the chamber bottom, and said space is defined by a cylindrical opening in the center of the disc.