Fuel injector with porous element for atomizing fuel under air pressure
AssigneeSiemens Automotive Corporation
InventorsJeffrey B. Pace, Vernon R. Warner
Life of this patent
Estimating the term…
Abstract
A fuel injector has a shroud surrounding its valve orifice. The shroud carries a porous element spaced from the orifice to define a chamber. Air passages are provided through the shroud for injecting air under pressure into the chamber. The fuel sprayed onto the porous element from the orifice enters the pores of the element and increases the wetted surface area such that the air under pressure passing through the porous element shreds the fuel films and finely atomizes the fuel for egress from the porous element into the internal combustion engine.
Claims12
A fuel injector for an internal combustion engine, comprising:
- an injector body having a seat, an orifice through said seat and an injector needle reciprocable along an axis between a first position having a tip thereof spaced from the valve seat defining a passage for flowing fuel between said needle and said seat and through said orifice and a second position with the tip engaging said seat and closing said fuel passage;
- a shroud defining a chamber downstream of said orifice for receiving the fuel flowing through said orifice and carrying a porous element spaced from said orifice and on an opposite side of said chamber from said orifice for receiving fuel flowing through said orifice and said chamber;
- an air passage for flowing air under pressure into said chamber for flow through said porous element, thereby atomizing the fuel in said porous element;
- and
- an outlet on the side of the porous element opposite the chamber for flowing the atomized fuel from the injector.
A fuel injector for an internal combustion engine, comprising:
- an injector body having a seat, an orifice through said seat and an injector needle reciprocable along an axis between a first position having a tip thereof spaced from the valve seat defining a passage for flowing fuel between said needle and said seat and through said orifice and a second position with the tip engaging said seat and closing said fuel passage;
- a shroud defining a chamber downstream of said orifice for receiving the fuel flowing through said orifice and carrying a porous element spaced from said orifice and on an opposite side of said chamber from said orifice for receiving fuel flowing through said orifice and said chamber;
- an air passage for flowing air under pressure into said chamber for flow through said porous element, thereby atomizing the fuel in said porous element;
- and
- an outlet on the side of the porous element opposite the chamber for flowing the atomized fuel from the injector;
- wherein the porous element has first and second layers, with the first layer between said second layer and said chamber and having a pore size larger than a pore size of said second layer, whereby the first layer provides a coarse fuel/air mixing interaction and the second layer provides a fine fuel/air mixing interaction.
A fuel injector having an orifice for periodically injecting fuel into an internal combustion engine, comprising:
- a porous element carried by the injector and spaced downstream from an orifice of a valve nozzle, the porous element receiving the fuel flowing through the orifice;
- an air passage carried by the injector for directing air under pressure onto and through said porous element for causing fine droplet atomization of the fuel in the interstices of the porous element;
- and
- a lower orifice disk placed on the side of the porous element remote from the orifice of the valve nozzle and having an opening for directing the fuel/air mixture flowing through the porous element.
A fuel injector having an orifice for periodically injecting fuel into an internal combustion engine, comprising:
- a porous element carried by the injector and spaced downstream from an orifice of a valve nozzle, the porous element receiving the fuel flowing through the orifice;
- and
- an air passage carried by the injector for directing air under pressure onto and through said porous element for causing fine droplet atomization of the fuel in the interstices of the porous element;
- wherein said porous element has first and second layers, with the first layer between said second layer and the orifice and having a pore size larger than a pore size of the second layer, whereby the first layer provides a course fuel/air mixing interaction and the second layer provides a fine fuel/air mixing interaction.
Dependencies are inferred from the claim text.