Siemens Automotive Corporation

Jeffrey B Pace

Vernon R Warner

Danny O Wright

John F Nally, Jr

James A Nitkiewicz

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.

Fuel injector with porous element for atomizing fuel under air pressure

An injector needle/armature assembly stroke is controlled so as to minimize opening and closing impact forces. The controlled motion eliminates or significantly reduces the problems associated with valve bounce, providing less acoustic emission, reduced wear, improved spray characteristics and better flow regulation. The current applied to the electromagnetic coil of the injector in accordance with a modified injector timing pulse waveform serves to reduce impact velocities at each end of the armature stroke. The waveform can be optimized for a class of injectors with a pulse width modulated waveform, repeatedly re-energizing and de-energizing the electromagnetic coil in accordance with an optimized on/off pulse train.

Armature motion control method and apparatus for a fuel injector

A flow straightener and a controlled disturbance element are interposed between the injector needle seat and the discharge orifice disk of a fuel injector. The flow straightener straightens flow eliminating turbulence prior to fuel discharge. The controlled disturbance disturbs the fuel flow providing controlled atomization. A spacer is provided between the flow straightener and the controlled disturbance element as well as between the controlled disturbance element and the discharge orifice disk delimiting flow recovery regions. By varying the diameter and/or height of the spacers, in conjunction with the controlled disturbance element, an adjustable level of flow disturbance can be obtained, leading to variable degrees of atomization. In one arrangement, the flow straightener and the controlled disturbance element are combined into a single flow element performing the functions of both the flow straightener and the controlled disturbance element.

Method and apparatus for controlled atomization in a fuel injector for

Opening and closing times of a fuel injector are accurately determined in accordance with the energy content of an accelerometer trace. The energy content of an accelerometer trace is determined in accordance with a predetermined relation. A line is defined between known points prior to and after the opening or closing time. The normal distance between the line connecting known points and the accelerometer trace energy content is maximum at the inflection point, which corresponds to the opening or closing time. With this data, an ECU can be properly programmed to more accurately control an injector stroke, thereby improving engine performance.

Method and apparatus for accurately determining opening and closing

A fuel injector for an engine includes a fuel volume having an air inlet port having a porous membrane. The membrane is permeable to air and impermeable to fuel whereby air inlet to the fuel volume forms a two-phase air bubble/fuel dispersion within the fuel volume. Upon actuation of the needle valve of the injector, this two-phase air bubble/fuel dispersion flows through the orifice into the engine whereby improved atomization, burn and fuel economy with resultant reduction in emissions are provided.

Fuel injector with air bubble/fuel dispersion prior to injection and

The fuel and air supply system of the present invention provides fuel from a fuel pump at a first pressure upstream of a pressure reducer, fuel being provided directly to the fuel injector at a reduced pressure on the downstream side of the pressure reducer. A bypass line in communication with the fuel line upstream of the pressure reducer provides fuel to an air reservoir at the first pressure. The air reservoir lies in communication with a porous member(s) in the fuel injector in an air inlet to a fuel volume within the injector upstream of the pressure reducer. Upon flow of fuel into the air reservoir and closure of normally open fuel and air valves in the reservoir, air at the first pressure is supplied the porous member(s), creating a pressure differential across the member(s), causing air to flow through the porous member(s) to form air bubbles in the fuel volume for two-phase flow through the fuel injector orifice. The air flows for a predetermined time until the reservoir fills with fuel which precludes further air flow into the injector. Upon shutdown of the engine, the valves in the air reservoir open, draining the fuel from the air reservoir and enabling air at atmospheric pressure to enter the reservoir, returning the system for reuse upon engine startup.

Fuel/air supply system for a fuel injector and methods of operation

Multiple orifice disks are stacked and include one or more swirl disks. The effect of the stack of disks is to impart swirl to the fuel stream being ejected from the injector in a relatively short axial length. The geometry of the disks in the stack are such that the fuel from the top disk enters the bottom disk at the end of a pattern which operates to impart a swirl component to the fuel. The pattern in the bottom disk is typically a two layered pattern wherein the top layer is one half the thickness of the thin disk and the bottom layer is the second half of the thickness of the thin disk.

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Newport News, VA, United States of America

Jeffrey B Pace