GB2489225A - Spark plug having a direct injection fuel injector - Google Patents

Abstract

Disclosed is a spark plug for a direct injection engine having an integral fuel injector ("injector-igniter"), the two functions, fuel injection comprising a nozzle valve assembly 1 and ignition comprising a spark gap 4, being integrated into a single structural unit. By virtue of the miniature size of its injector nozzle valve assembly 1 disposed at or within the beneficially cooling tip of the traditional (eg. 14mm) spark plug threaded mounting cylinder 2, the two demanding and competing functions are segregated and prevented from compromising each other. The injected spray plume can be optimally positioned for combustion efficiency benefits of so-called "spray guided" direct injection.

Description

SPARK PLUG HAVING A DIRECT INJECTION FUEL INJECTOR

FIELD OF THE INVENTION

The present invention pertains to a spark plug for a direct injection type engine having an integral fuel injector, the two distinct functions, fuel injection and ignition, being combined into a single structural unit.

PRIOR ART PATENTS

An example of a relatively well-designed and workable combination of a spark plug with a central coaxial fuel injector was submitted for a US patent in 1944, but granted in 1949, US2459286. Typical of practically all fuel injectors to the present day, it suffers from massive, inertially sluggish moving parts of limited abilty to respond to the fine injection control demanded of present-day combustion standards. This design, as with state of the art designs, suffers also from its use of the tip of the fuel injector as the central electrode of the spark plug, causing the critical tip of the fuel injector to suffer the intense heating caused by the spark above heating due to the combustion environment alone. In its day is of low performance engines, its central coaxial fuel injector may not have been challenged by the tar formation and coking problems in the nozzle orfices and nozzle valve parts of the hot modern engine combustion environment, which would indicate cooling the fuel injector by maximum thermal communication with the cooling outer shell of the spark plug.

As with all centrally located coaxial fuel injector placements, the issue of providing adequate central electrode dielectric insulation both in terms of surface discharge path distance as well as dielectric (ceramic) thickness offers a challenge, due to its compromise of standard spark plug center electrode electrical insulating norms.

The approach of US7086376 places the fuel injector side by side in parallel with the spark plug, instead of concentric with it, in the process eliminating the spark-plug outer shell apparently to save precious cylinder head space. But by dispensing with the outer shell which normally surrounds the inner sparking electrode, this design forfeits the significant advantage of having extensive cooling contact with the its hole of penetration into the combustion chamber, which goes to waste for this valuable purpose. Also, the design suffers from use of a massive and hence inertially sluggish moving valve pintle which does double duty as a center sparking electrode, exposing much of the pintle's surface area to the hot combustion chamber environment, posing a significant flame quenching presence at the sparking location and inviting injector coking. Because the tip of the nozzle valve closure pintle is used as an electode for the spark discharge, it is exposed to this significant additional source of heating, inviting coking problems.

By a variation of the above US7086376 placing its fuel injector element central in a coaxial design, which has been the prevailing approach, US7201136 is improved by gaining a relatively normal cooling threaded outer shell, but retains the same massive center electrode nozzle valve pintle design, suggesting its aforementioned problems.

Also, in order to enjoy pyrolytic cleaning of the dielectric insulator surface, that surface must maintain a working temperature of between 500°C to about 850°C, which challenges the need for the fuel injector parts to remain cool. Also the massive pintle diameter appears to limit the ability to adapt a range of thermal operational geometries, otherwise known as,,heat ranges", to the central electrode insulator.

US6748918 concentrates on locating the spark in the vicinity of the injected spray.

This approach uses the concentric massive and therefore sluggish pintle valve design most often favored by past efforts, with its use of the central fuel injector tip as also the spark plug tip, resulting in spark heating of the latter, which is further challenged by having to transfer the heat from the central electrode/fuel injector nozzle through the dielectric is insulator to the cooling shell. This design appears to lack an effective central electrode dielectric surface discharge prevention design flexibility, as well as any indication of how that insulating sufrace is intended to be pyrolytically cleaned by maintaining a strict operational temperature range of between about 500° C to about 850° C for each intended combustion chamber condition and configuration.

US6871630 abandoned conventional efforts to integrate the spark plug concentrically with the fuel injector, and placed them distinctly side by side without attempt to share their structures in order to create the spark gap. Placing these functions side by side avoids compromising the conflicting ignition and fuel injection functions, but does incur a substantial cost in terms of space required by the non-standard large hole in the cylinder head. The design also does not appear to be able to aim its fuel jet to pas closely in the vicinity of the spark gap for optimum ignition.

EP 661 446 suffers from imprecise and variable location of the spark discharge path in relation to the fuel spray, wherein ignition of the jet root of the fuel jet is sought, resulting in variable ignition effectiveness from one spark to the next. It also suffers other liabilities in common with the above.

The present invention solves the typical shortcomings of the art listed above by virtue of miniaturization of the injector nozzle valve, which makes possible or facilitates the following improvements difficult to achieve simultaneously by the prior art: 1, elimination of the massive pintle valve which challenges contemporary requirements for extremely fine (quick) and precise injection control; 2, avoidance of use of the pintle valve as a sparking electrode (unneccessarily heating the injector nozzle valve); 3, placing the miniature and minimal heat capacity (easily cooled) nozzle valve as part of or bonded to the spark plug's massive cooling housing shell, and more specifically its threaded mounting cylinder, which may advantageously be the 14mm global standard, providing a superior cooling path to the cylinder head, in contrast to being thermally insulated at the spark plug's coaxial center by its columnar insulator; 4, freedom to implement (preserve) the traditional and highly developed methods for io providing central spark plug heat ranges by means of well known dielectric insulator shapes or their non-circularly symmetrical analogues which prevent fouling; 5, minimization of the size and especially the diameter of the combustion chamber penetrating insertion hole for the injector-igniter, conserving valuable cylinder top space; 6, freedom to position the nozzle valve and aim its direct injected fuel spray plume to a is precise near proximity to the spark gap for immediate ignition without wetting (fouling) the spark gap or any part of the combustion chamber, to achieve the high efficiency of so-called "spray guided" combustion.

7, avoidance of compromise of the competing and demanding fuel injection and spark ignition functions by segregating them physically.

DISCLOSURE OF THE INVENTION

According to a first aspect, the present invention consists in an injector-igniter apparatus comprising spark ignition device structurally integrated with a direct-Injection (Dl) fuel injector into a common structure for use in an internal combustion engine, the apparatus comprising a high voltage current path which conducts a high voltage to a spark gap between dielectric insulated electrodes of opposite polarity; wherein the Dl fuel injector comprises a nozzle valve assembly, in turn comprising a spring assembly; a valve seat; and a valve closure element pressed by the biased spring assembly against the valve seat; and wherein the direct injector comprises at least one fluid medium channel between the fluid medium pressure source and valve seat; the apparatus being characterized by at least one of: both the spring assembly (17) and the valve closure element (18), by virtue of their compactness, being disposed entirely beyond a gas flow point (32) on the surface of the dielectric columnar insulator(9) of a center electrode (2) of said spark-ignition device, in the in the direction of the combustion chamber along the injector-igniter insertion vector of penetration into the internal combustion engine; the gas flow point, when the apparatus is installed in an engine, being in freely replenishing gas communication with the combustion chamber; the nozzle valve assembly function being spatially segregated from the spark-ignition function to satisfy their conflicting requirements; and the nozzle valve assembly function being localized for effective fuel injection positioning together with permitting effective spark gap positioning.

The invention also provides an apparatus wherein the spring assembly comprises at least one Belleville spring, characterized by at least one of: the at least one Belleville spring having an annular and wave shaped corrugation symmetric about the Belleville io spring axis; the Belleville spring annular wave-shaped corrugation comprising either one or two wave peaks; and the transition of the annular wave-shaped corrugation of the Belleville spring to its outer support area and/or the Belleville spring central support area being located at a point of the wave profile where the tangent to the wave shape of the Belleville spring in its biased state is perpendicular to the Belleville spring axis within ±30°.

is The invention also provides an apparatus wherein: the inward or outward-opening fuel injector nozzle valve assembly housing is rigidly joined to and at any depth or angle embedded into the tip portion of a preferably threaded mounting cylinder of the body of the apparatus, the mounting cylinder, when the apparatus is installed into an engine, penetrating by its end surface into the combustion chamber of an internal combustion engine either by means of screw threads on its surface, or by other mounting means; a columnar dielectric insulated center electrode of one polarity is disposed within the preferably threaded mounting cylinder, whose spark-gap tip emerges from the combustion chamber end of said preferably threaded mounting cylinder; the spark gap tip is dielectrically insulated from an opposite polarity high voltage current path supported by said preferably threaded mounting cylinder of the injector-igniter, along with at least one side electrode rigidly supported by the end of said cylinder and served by said current path; and the spark gap is disposed between the said center electrode and side electrode, of opposite polarities.

The invention also provides an apparatus wherein; the nozzle valve assembly is disposed substantially to one side of a plane comprising the central axis of the preferably threaded mounting cylinder; an axial view of said nozzle valve assembly presents an eye-shaped profile with the outline of its Belleville spring cylindrical cavity as its "iris'; the outer curve of said eye-shaped profile either nearly coincides with the circle of the combustion chamber penetrating hole of the preferably threaded mounting cylinder or that of its threads; and the middle part of said eye-shaped surface cross-section profile near the apparatus' central axis borders the cylindrical spring cavity iris" establishing a spring cavity wall, after which said wall proceeds to each corner of the "eye; and the eye-shaped geometry benefits cooling and structural contact of nozzle valve assembly (1) with the preferably threaded mounting cylinder (2) and engine cooling system, pyrolytic cleaning exposure of the columnar insulator to the combustion chamber as needed, and spark gap exposure for fuel ignition.

The invention also provides an apparatus wherein the nozzle valve assembly's spring assembly and valve closure element have a common vector oriented extent from its one end to its other end in the in the direction of the combustion chamber along the io injector-igniter insertion vector of penetration into the internal combustion engine; which common vector oriented extent falls into said vector oriented lateralism with the part of the surface of the dielectric columnar insulator which is exposed to combustion chamber gas circulation when the apparatus is installed in an engine, and/or a distance beyond the end of the dielectric columnar insulator toward the combustion chamber along said vector, is beneficially limiting the position of nozzle valve assembly.

The invention also provides an apparatus wherein; an axial extent of the center electrode geometry within said region of lateralism includes a departure of its local axis from the principal axis of the center electrode, tilting to avoid the adjacent nozzle valve assembly and toward the opposite adjacent inner wall of the spark-plug preferably threaded mounting cylinder.

The invention also provides an apparatus wherein the opposite adjacent inner wall of the spark-plug preferably threaded mounting cylinder comprises a local chamfer.

The invention also provides an apparatus wherein axial positioning of the of the fuel injecting end of the nozzle valve behind the spark gap is adapted to enable the angular orientation of a local trajectory of part of its ejected vapour plume(s) into proximity of the spark gap sufficient to achieve its ignition when the apparatus is installed in an engine.

The invention also provides an apparatus wherein: the axially oriented lateral disposition of the nozzle valve spring assembly and valve closure element relative to the dielectrically insulated center electrode while maintaining high-voltage dielectric breakdown clearance from adjacent surfaces includes the insulated center electrode conductor and dielectric structure filling the crescent-shaped space available to it, where the region of lateralism of the center electrode assumes a cross-section profile curvature which is more convex on its side facing away from the nozzle valve assembly than on its side facing the nozzle valve assembly, and which may become concave and curving around the nozzle valve assembly; and both extremities of this region of lateralism of the described center electrode cross-section profile transition to their adjacent center electrode trunk and tip circular profiles by generally gradual and uniform transition, thereby establishing center electrode cooling and structural strength to the extent needed to establish a spectrum of spark-plug operational heat ranges.

The invention also provides an apparatus wherein the nozzle valve assembly housing is made substantially of dielectric material.

The invention also provides an apparatus wherein the nozzle valve assembly housing comprises a thermal insulating barrier.

The invention also provides an apparatus for use with a fluid medium control valve, the control valve being characterized by at least one of: the control valve valve closure element being biased by, and being solely or in concert with supplementary sleeve is bearing(s) supported, or aligned, or centered in its valve seat by, a spring assembly of parallel stacked Belleville springs, the control valve being structured according to outward-opening fuel injector nozzle valve assembly comprising a valve closure element comprising an integral valve stem shaped part which passes through and is guided directly or indirectly by aid of said Belleville spring stack spring assembly; employing the direction of the controlled fluid medium pressure which reinforces the valve closing spring assembly bias, being directed from the larger diameter of the valve seat taper towards its smaller diameter; and having a valve stem shaped part which assumes by axial extension from either end of the control valve push rod and/or pull rod control functions.

The invention also provides an apparatus characterized in that: the fluid medium control valve employs the bearing system of the Belleville spring stack spring assembly biased valve closure element which is frictionless and uses no sleeve bearing; and the mechanical valve coupling of the control valve by which said valve closure element is mechanically coupled to the outside of the cavity enclosing said valve closure element is a smooth cylindrical valve lifter element in a close-fitting smooth bore restrictive to fluid medium leakage from said cavity, leakage being entirely sealable by a pressure tight flexible diaphragm.

The invention also provides an apparatus comprising a fluid medium control valve in fluid medium communication with its nozzle valve assembly, the control valve being either structurally integral to, or structurally discrete from the main body of the injector-igniter.

The invention also provides an apparatus comprising a high-speed actuator actuated fluid medium metering valve system of an energize to meter type, characterized by at least one of: the high-speed actuator driving a push-only coupler connected to a normally closed high pressure inlet control valve, operable to insure by a push coupler linkage gap of said push-only coupler that no force is transmitted to the high pressure inlet control valve while said high-speed actuator is not energized, despite normal system tolerance changes comprising limited valve seat wear; the normally closed high pressure io inlet control valve being operable to meter a pressurized fluid medium from a high pressure source into a fluid medium channel connected to an inward-opening or outward-opening fluid medium injector nozzle valve assembly; the direction of fluid medium pressure being operable to reinforce the normally closed high pressure inlet control valve closing spring bias on its valve closure element, directed from the larger diameter of its is valve seat taper towards its smaller diameter; the fluid connection between the high pressure inlet control valve and the nozzle valve assembly also being connected to the input of a residual pressure discharge control valve; the residual pressure discharge control valve being oriented so that its input pressure likewise assists in holding its valve closure element closed, which is operable to open at nearly the same instant that the high pressure inlet control valve is closed by de-energization retraction of said push-only coupler; de-energization retraction of said push-only coupler allowing the residual pressure contained between the fully closed high pressure inlet control valve and the spring assembly biased closed but ejecting nozzle valve assembly to instantly drop to a level below the nozzle valve assembly closure pressure to a preferably regulated fluid medium boiling prevention pressure above the fuel vaporization pressure at the injector working temperature in the case of liquid fuel by the optional anti-boiling pressure regulator; the residual pressure drop being effected by opening of the residual pressure discharge control valve by its mechanical linkage to the pull-only coupler connected by a shaft connection axially passing though the high pressure inlet control valve to the push-only coupler at its opposite end; the shaft connection axially passing though the high pressure inlet control valve (38) to the push-only coupler (42) causing the valve closing bias spring assembly of the high pressure inlet control valve to overpower the weaker valve closing bias spring assembly pressure of the oppositely oriented residual pressure discharge control valve, so that while the high pressure inlet control valve (stronger bias) is normally closed, the residual pressure discharge control valve (weaker bias) is pulled and held open against its spring assembly by the more powerful spring assembly of the former, except when the former is overpowered via the push-only coupler by the high-speed actuator, forcing the high pressure inlet control valve open, and releasing the residual pressure discharge control valve so that it closes by its own relatively weakest spring assembly, preferably insuring by a pull-only coupler pull coupler linkage gap that no force is applied to said control valve while said actuator is energized despite normal tolerance changes including limited valve seat wear.

The invention also provides an apparatus comprising a high-speed actuator, the high-speed actuator being operable to actuate a fluid medium metering valve system of energize to meter type, comprising a control valve, the high-speed actuator comprising at io least one of a solenoid, piezoelectric, or similar high-speed actuator.

The invention also provides an apparatus comprising a solenoid, piezoelectric, or similar high-speed actuator actuated metering valve system of energize to inject type in fluid medium communication with its nozzle valve assembly, the metering valve system being either structurally integral to, or structurally discrete from the corpus of the injector-is igniter.

The invention also provides an apparatus comprising a rotationally adjustable (swiveling) fuel inlet collar axially extended to perform a stand-off function to elevate both the fuel inlet pipe as well as the high-voltage spark plug cable connector above the gasket surface of the mounting hole of said injector-igniter to facilitate connection and service access to the combined injector-igniter unit.

The invention also provides an apparatus wherein the fuel inlet collar sealing washer (gasket) on the collar inner gasket seat is operable to perform a fuel filtering function in its multiple function as the fuel channel and high pressure gasket between the fuel inlet collar annular groove and inlet annular groove in the spark plug seat of the housing shell of the injector-igniter, such that the collar annular groove functions as a sediment trap under the sealing washer multi-function gasket/filter.

The invention also provides an apparatus comprising a means for promoting flash boiling of the injected fuel spray after it is sprayed into the combustion chamber, while maintaining its liquid state within the nozzle valve outside of the injection phase of its injection cycle characterized by any one of: a controlled source of heating in concert with a heating control means to limit the flash boiling temperature of the fluid medium within the nozzle valve prior to injection to above a minimum foreseeable flash-boiling working temperature as required for its flash boiling after it is injected into the combustion chamber, and preferably also to below a maximum allowable temperature; a pressure control means to maintain the fluid medium within the nozzle valve above the vapor pressure of the fluid medium during the part of the injection cycle when the fluid medium is not being injected.

According to a second aspect, the present invention consists in a Belleville spring, characterized by at least one of: the at least one Belleville spring having an annular and wave shaped corrugation symmetric about the Belleville spring axis; the Belleville spring annular wave-shaped corrugation comprising either one or two wave peaks; and the transition of the annular wave-shaped corrugation of the Belleville spring to its outer io support area and/or the Belleville spring central support area being located at a point of the wave profile where the tangent to the wave shape of the Belleville spring in its biased state is perpendicular to the Belleville spring axis within ±300.

According to a third aspect, the present invention consists in a fluid medium control valve, the control valve being characterized by at least one of: the control valve valve is closure element being biased by, and being solely or in concert with supplementary sleeve bearing(s), supported, or aligned, or centered in its valve seat by, a spring assembly of parallel stacked Belleville springs; the control valve being structured according to outward-opening fuel injector nozzle valve assembly, comprising a valve closure elements comprising an integral valve stem shaped part which passes through and is guided directly or indirectly by aid of said Belleville spring stack spring assembly; employing the direction of the controlled fluid medium pressure which reinforces the valve closing spring assembly bias, being directed from the larger diameter of the valve seat taper towards its smaller diameter; and having a valve stem which assumes by axial extension from either end of the control valve push rod and/or pull rod control functions.

The invention also provides a control valve characterized in that: the control valve, bearing system of the Belleville spring stack spring assembly biased valve closure element is frictionless and uses no sleeve bearing; and the mechanical valve coupling of the control valve by which said valve closure element is mechanically coupled to the outside of the cavity enclosing said valve closure element is a smooth cylindrical valve lifter element in a close-fitting smooth bore restrictive to fluid medium leakage from said cavity, leakage being entirely sealable by a pressure tight flexible diaphragm on the outside of the cavity.

According to a fourth aspect, the present invention consists in a high-speed actuator actuated fluid medium metering valve system of an energize to meter type, characterized by at least one of: the high-speed actuator driving a push-only coupler connected to a normally closed high pressure inlet control valve, operable to insure by a push coupler linkage gap of said push-only coupler that no force is transmitted to the high pressure inlet control valve while said high-speed actuator is not energized, despite normal system tolerance changes comprising limited valve seat wear; the normally closed high pressure inlet control valve being operable to meter a pressurized fluid medium from a high pressure source into a fluid medium channel connected to an inward-opening or outward-opening fluid medium injector nozzle valve assembly; the direction of fluid medium pressure being operable to reinforce the normally closed high pressure inlet io control valve closing spring bias on its valve closure element, directed from the larger diameter of its valve seat taper towards its smaller diameter; the fluid connection between the high pressure inlet control valve and the nozzle valve assembly also being connected to the input of a residual pressure discharge control valve; the residual pressure discharge control valve being oriented so that its input pressure likewise assists in holding its valve is closure element closed, which is operable to open at nearly the same instant that the high pressure inlet control valve is closed by de-energization retraction of said push-only coupler; de-energization retraction of said push-only coupler allowing the residual pressure contained between the fully closed high pressure inlet control valve and the spring assembly biased closed but ejecting nozzle valve assembly to instantly drop to a level below the nozzle valve assembly closure pressure to a preferably regulated fluid medium boiling prevention pressure above the fuel vaporization pressure at the injector working temperature in the case of liquid fuel by the optional anti-boiling pressure regulator; the residual pressure drop being effected by opening of the residual pressure discharge control valve by its mechanical linkage to the pull-only coupler connected by a shaft connection axially passing though the high pressure inlet control valve to the push-only coupler at its opposite end; the shaft connection axially passing though the high pressure inlet control valve (38) to the push-only coupler (42) causing the valve closing bias spring assembly of the high pressure inlet control valve to overpower the weaker valve closing bias spring assembly pressure of the oppositely oriented residual pressure discharge control valve, so that while the high pressure inlet control valve (stronger bias) is normally closed, the residual pressure discharge control valve (weaker bias) is pulled and held open against its spring assembly by the more powerful spring assembly of the former, except when the former is overpowered via the push-only coupler by the high-speed actuator, forcing the high pressure inlet control valve open, and releasing the residual pressure discharge control valve so that it closes by its own relatively weakest spring assembly, preferably insuring by a pull-only coupler pull coupler linkage gap that no force is applied to said control valve while said actuator is energized despite normal tolerance changes including limited valve seat wear.

According to a fifth aspect, the present invention consists in a high-speed actuator, the high-speed actuator being operable to actuate a fluid medium metering valve system of energize to meter type, comprising a control valve, the high-speed actuator comprising at least one of a solenoid, piezoelectric, or similar high-speed actuator.

The invention also provides a solenoid, piezoelectric, or similar high-speed actuator actuated metering valve system of energize to inject type in fluid medium communication with its nozzle valve assembly, said metering valve system being either io structurally integral to, or structurally discrete from the corpus of the injector-igniter.

According to a sixth aspect, the present invention consists in a piezoelectric stack, characterized in that its fixed end has a pivoting support and its moving end is biased, supported, and centered by a parallel stack of one or more Belleville springs.

According to a seventh aspect, the present invention consists in a fuel injector is comprising a means for promoting flash boiling of the injected fuel spray after it is sprayed into the combustion chamber, while maintaining its liquid state within the nozzle valve outside of the injection phase of its injection cycle characterized by any one of: a controlled source of heating in concert with a heating control means to limit the flash boiling temperature of the fluid medium within the nozzle valve prior to injection to above a minimum foreseeable flash-boiling working temperature as required for its flash boiling after it is injected into the combustion chamber, and preferably also to below a maximum allowable temperature; a pressure control means to maintain the fluid medium within the nozzle valve above the vapor pressure of the fluid medium during the part of the injection cycle when the fluid medium is not being injected.

The present invention exploits the unprecedented miniature dimensions, negligible inertia and number of moving parts of the fuel injector according to patent application PCT/EP2OIU/061790 (for example, FIG 6 & 7) enabling the unique placement of a complete, uncompromised high performace fuel injector (limited to its nozzle valve function) 3.5mm long x 6mm diameter, at the tip of a practically standard 14mm automotve spark plug (see also FIG 9 -II). This technical solution by way of miniaturization offers superior direct-injecton fuel injection performance while preserving most of the attainments of over a century of development of modern standard spark plugs achieving superior performance and long life matching that of modern fuel injectors.

The most interesting example of an embodiment of the present invention, depicted in FIG 1-3, 21, 22, 24 (in contrast to the more primitive and obvious example depicted in FIG 4 & 5 wherein the miniature fuel injector part, i.e. nozzle valve, at the tip of the spark-plug protrudes substantially beyond the end of the spark-plug housing into the combustion chamber in order to avoid interference with the central spark electrode), disposes substantially said entire miniature fuel injector nozzle valve assembly, including all of its moving parts within and as part of the threaded, engine-penetrating part of the cooling spark plug shell such that the heated end surface of the fuel injector does not extend substantially beyond the plane of the end surface of the spark-plug cylindrical housing. In io other words, in this most ambitious embodiment challenged by the functional demands of the central electrode with which it inventively shares extremely limited parallel space within the same cylindrical spark plug threaded shell, the direct-injecton fuel injector part avoids protruding into the combustion chamber by complete recessing into the cooling spark plug shell tip, thereby gaining greatly in cooling, eliminating the unrecessed version's flame is quenching and obstruction to the flame propagation front, and attaining ideal positioning of the spray nozzle behind the spark gap to direct the injected fuel spray into the optimum proximity to the spark gap for ignition. In order to achieve this counterintuitive recessing of the fuel injector into the spark plug body, a novel central electrode geometry is advanced.

The more recently popular clamp-mounting methods for fuel injectors are obviously adaptable to the present invention in lieu of threaded mounting, where preferred, without significantly affecting the design of the examples provided in the drawings, except for compromising the threaded mounting advantage of tight and increased heat sinking surface contact to the cooling cylinder head.

Finally, as the most comprehensive (non-limiting) example of an embodiment of the present invention, a complete high-speed piezoelectric fuel injector fully integrated with a spark plug, combining all of the major advantages of the present invention is offered (cf. FIG 21 -23).

Due to its frictionless principle of operation (cf. FIG 6 & 7), in common with the Stirling engine, most examples of said injector are amenable to injecting any type of fluid medium, specifically liquid or gaseus fuel or water, or any mixture or sequence of injection of any of these, and is amenable to both compression and spark ignition modes of operation, wherein current technology supports both in a single engine, making the present invention an optimal means for advancing the latter technology.

As its fundamental inventive step the present invention applies the inventive ultra compact fuel injector presented in application PCT/EP2UIO/061790 to the tip of a nearly standard spark plug (cf. FIG 1, 21, 22). Priorto PCT/EP2OIO/061790, such location would have been unthinkable. PCT/EP2OIO/061 790 inventively eliminates numerous technichal challenges, costs, and compromises by dramatic fuel injector nozzle valve miniaturization based on practically eliminating the fuel injector's massive and normally long valve stem (often called a,,pintleo) and bulky valve springs, leaving as moving parts scarcely more than the original normal conical nozzle valve tip with its conical valve seat, the entire valve closure element being reduced to the size of a large grain of sand (the typical current nozzle valve pintle tip size) without loss of function or capacity. This results in an entire superior performance fuel injector in a cylinder of 6mm diameter by 3.5mm io height which now easily fits in the tip of a standard 14mm spark plug, etc. In mechanical valve guiding solutions where a valve stem is useful, a minute vestige of the former massive pintle remains as a negligible fraction of the mass of the valve sealing tip, in contrast to the opposite situation dominating the state of the art as a massive anchor dragging down fuel injector performance. Despite said fuel injector's overall ultra is compact configuration and dimensions, the injection performance determining parameters and dimensions of its nozzle valve closure cone, spring forces, and nozzle tip at least equal those of the state of the art for any scale of engine size, insuring comparable fuel delivery and spray patterns while enabling increase in speed of operation. This performace advantage is achieved due to almost complete elimination of the traditional inertial mass of a typical state of the art valve closure element, along with total elimination of complex additional parts required to overcome said inertia.

Beyond these fundamental advantages, PCT/EP2UIO/061790 offers a rich variety of inventive nozzle valve configurations, all of which are applicable to the nozzle valve elements of the present invention. But the outward opening poppet valve applications to nozzle valves inventively presented in PCTIEP2O1OIO6I79O also benefit the present invention's fuel control valve and metering valve applications, where the relatively small valve closure element displacements characteristic of fuel injectors prevail, which is the prerequisite for the effective dynamic application of parallel stacked Belleville springs, which is the foundation for the inventive miniaturization without loss of performance fundamental to PCTIEP2OIOIO6I79O and of the present invention. Further yet, the present invention expands the scope of PCT/EP2OIO/061790 in applying the inventive Belleville spring corrugation and its application to parallel stacks of Belleville springs in ideally adaped service for piezoelectric stack biasing, aligning, and centering, in the same way as proved effective for biasing, aligning, and centering of nozzle valve closure The simplicity of the current invention, whose technical and economic advantages are based on the miniature size and inertial mass of its fuel injector component, facilitates designs for demanding spark ignition liquid fuel and gaseous fuel engine applications, as well as simple and easy retrofit to existing engines, bringing performance benefits with reduced emissions. Thr invention's simplicity does not limit, but rather creates the conditions for superior performance. The ultra compact injector nozzle spring design and operation upon which PCT/EP20101061790 application is based, raises the speed, frequency, and precision of injection control without compromising fuel delivery rates for internal combustion engines.

Robust protection from the heat of the combustion chamber is afforded primarliy by io maximum cooling contact of the metallic or ceramic miniature fuel injector structure with the threaded part of the spark plug shell (or the corresponding nonthreaded cooling regions of popular threadless fuel injector designs), aided by substantial fuel flow cooling of the minimal heat capacity miniature structure, with optional ceramic or other state of the art thermally protective coatings (cf. FIG 4 & 5) as the application or wide variety of is configuration may demand in limited cases. Such cooling contact may be accomplished by brazing or other union of the fuel injector part with the spark plug shell, or the fuel injector housing may be machined of one piece integral with the spark plug shell.

The ultraminiature external size of said fuel injector pad (demonstrated by mathematical modelling as feasible in a cylindrical example of an embodiment of 3.5mm length and 6mm diameter) uniquely enables inventive installation of said fuel injector at the tip of the globally dominant standard 14mm spark plug (cf. FIG 1) without need for substantially modifying either said spark plug or the fuel injector. Commercial success has eluded over a century of persistent patented attempts at integration of the spark plug and the fuel injector.

Both the central spark electrode and the fuel injector body coexist without conflict in the same cylindrical space within (and possibly beyond) the end of the spark plug cylindrical body, which in the case of a standard spark plug configuration would be its threaded shell (cf. FIG 2-5), easily convertible to popular clamp-mounting common to fuel injectors. The internally cylindrical fuel injector body (ie nozzle valve assembly housing) occupies substantially the space to one side of the spark plug central axis, and the emerging tip of the center electrode must occupy the remaining opposite side of that cylindrical space (cf. FIG 9-11).

The present invention's most beneficial and innovative configuration disposes the fuel injector part recessed at least partly, and preferably entirely within the end of a substantially standard threaded metal spark plug casing (cf. FIG 1-3, 21,22). This inventive step involves the creation of an inventively robust, critically compact insulated center electrode tip side by side with the fuel injector, said center electrode tip portion diverging as it extends from the traditional conical center electrode axis and assumes a substantially crescent shape cross section, wherein is mintained a critical electrically insulating minimum arcing gap clearance from surrounding structures within the crescent- shaped space it occupies. In order to provide the center elctrode increased cross-sectional area for cooling and strength, it tends to,,wrap around' its adjacent fuel injector cylindrical contour by a roughly conforming adjacent curve, in order to maintain a neccessary electrically isolating and carbonization preventive heated space between the io ceramic-insulated center electrode and the threaded steel shell on one side, and the fuel injector on its opposite side (cf. FIG 11-14).

Where more heat is needed for pyrolytic decarbonization, the inventive geometry may be modified to a higher heat range" by reducing its cross-section area by making its cross-section progressively more circular in response to progressively increasing need for is more heat of decarbonization. Therefore, such transitional geometry from the crescent-shaped one to the one of circular cross-section would become increasingly more slender as it becomes more circular, and therefore hotter. This preferred geometrical modification for varying the heat range of the inventive center electrode geometry is presented in drawing FIG 12 A-E, respectively showing the geometrical progression of shapes from a cold center electrode to a hot one, in which the,,side view cross-section remains unchanged, but its 9Q° rotated front view x-ray view profile is made successively narrower, providing a range of increasing spark plug heat.

Besides varying spark-plug tip heat range by varying its center electrode's surface to volume ratio, as in FIG 12 A-E, the heat range of the central electrode tip may also be varied by utilization of materials of varying heat conductivity, without reducing its outer cross-section, by varying the proportion of its internally more heat conductive material, which traditionally has been its metal electrode. To this technique may be added use of new ceramics such as Aluminum Nitride (AIN) suitable for use as spark plug insulators which combine exceptional heat conductivity (higher than copper at high temperatures) with great dielectric strength, either alone, or in combination with the traditional or improved alumina (A1203) formulations. The use of AIN and A1203, including Zirconia-toughened alumina, either singly or in combination, would form the basis of practical examples of the present invention, to be discussed in more detail.

in order to sinter the conductive center electrode within its columnar insulator, the issue of matching thermal coefficients of expansion needs to be addressed, because the sintering temperature may be, depending on the process, commonly from a little over 1000°C to nearly 1700°C, but the working temperature of the center electrode and its columnar insulator is from about 450°C to about 900°C, with higher abnormal temperatures possible. Traditionally, the columnar insulator has been made of various formulations of Alumina independently of the nickel alloy center electrode, which is afterwards inserted into the nearly same size hole in the columnar insulator. Such assembly may not provide the best heat transfer, even if the fit is close, due to the imperfect contact on a microscopic scale, and due to thermal contact interface degradation due to thermal expansion cycling.

io A possible best axial ceramic distribution for the columnar insulator would be to use Aluminum Nitride (AIN) for the axial levels where the columnar insulator is in tight contact with its metallic housing shell, in order to exploit this tight contact for heat transfer from the center electrode to the cooled cylinder head of the engine, which ideally takes place mainly through the threads of the mounting cylinder part of the housing shell. AIN is has nearly the highest thermal conductivity of any ceramic and better than most metals, and is in most respects nearly ideal, and nearly as good as Alumina for use as a spark plug insulator, except that it generally needs a surface coating to withstand the harsh combustion chamber environment. Alumina, the traditional spark plug insulating ceramic, does not need such surface coating, but has a medium thermal conductivity. Therefore, attractive solutions would be to sinter the entire columnar insulator of Alumina, with a Copper-Tungsten matched TCE formulation at its core, or to sinter the entire columnar insulator of AIN with a Copper-Tungsten matched TCE formulation at its core. Or a composite columnar insulator may be sintered with a composite Copper-Tungsten matched TCE formulation at its core wherein, as described above, the axial extent of the columnar insulator in contact with its housing shell would be made of AIN, and the rest of it would be made of Alumina, especially the part exposed to the combustion chamber. The formulation of the Copper-Tungsten central electrode core would be made to match the TCE of the surrounding columnar insulator using functionally graded composite techniques to avoid thermal fracture. This, of course, is a simplified outline of a complex engineering challenge.

When using Aluminum Nitride with Thermal Coefficient of Expansion (TCE) of 4.3- 4.6 in combination with Alumina of TCE 6.7 -7.3, it is advantageous to use Copper-Tungsten pseudoalloy which can easily be formulated to exactly match the entire range of thermal coefficients of expansion of both Alumina and Aluminum Nitride for any given 3s temperature, wherein the formulation of the Copper-Tungsten alloy varies along the axis of the center electrode to match the TCE of the columnar insulator as the ceramic composition and its TOE of the varies axially. The transition between materials of different TOE is best done by functionally graded ceramic, which is simply a transition layer mixture of the two ceramics which is 100% one material at one end, and 100% the other material at its other end, with the percentage changing linearly or smoothly in between. The same applies to the Oopper-Tungsten alloy.

When such TOE matching is accomplished, it is possible to sinter the columnar insulator with its center electrode imbedded at its core as a single composite structure requiring no assembly, and having perfect mechanical and thermal contact at their material interface. Modern special methods of sintering allow drastic acceleration of sintering speed, and reduction of sintering temperatures, which result in higher quality results than traditional methods of sintering. Many of these methods known to the ceramics and powder metallurgy arts involve application of both heat and pressure in moulds, but with added material bonding activation on the atomic level provided by prior treatment of the ceramic powder materials to plasma streams, electric fields, and/or is electric currents. The plasma surface activation principle of the ceramic powder materials prior to pressing in a mould is fairly well known in the literature in relation to plasma beam Surface Activated Bonding (SAB) of ceramics, and has been applied to activating the loose ceramic powder as well as to polished ceramic surfaces to be joined at room temperature or higher. Also, sintering by microwaves of ceramic powders in moulds under pressure has been well studied, providing low temperature, extremely high quality sintering results. Such new sintering methods for ceramics are numerous, and beyond the scope of presentation here.

The beneficial novelty of the center electrode pertains to its lower end, below where the spark-plug hexagonal resides in a traditional design, becoming geometrically distinctive in its tip part adjacent to the fuel injector, exposed to the combustion chamber.

Whereas this tip part diverges angularly from the spark plug central axis, diminishing in cross-sectional area as it enters the crescent-shaped space next to the fuel injector (nozzle valve assembly) housing, we observe a downward tapering geometry whose cross-section begins at its upper end as the normal insulated spark plug electrode circular cross-section near to where the fuel injector part begins, which tapers downward, reducing at its end to a much smaller circular electrode tip, in a complex way so as to optimally fill its crescent shaped space, thus by this complex, generally crescent cross-section shape, gaining both structural strength and maximum cross-section area for heat removal from its sparking surface to the cooling cylinder head while maintaining required dielectric strength of the entire system to prevent arcing elsewhere than at the spark gap, while maintaining resistance to insulator as well as conductor surface erosion or cracking (cf. FIG 1, 2, 11 -14).

Part of achieving this electrode tip insulator durability objective, as well as the objective of varying its heat range, is achieved internally in the upper part of the center electrode, just below where the spark plug hexagonal traditionally resides. Here the objective is to achieve the best possible heat conduction from the spark plug tip to the threads or other corresponding seating surface of the spark-plug in the cylinder head.

The most effective means for achieving this is by making this upper part of the center electrode just above the conical part exposed to the combustion chamber from AIN ceramic, which combines exceptional heat conductivity with exceptional dielectric strength. The lower part of this structure, which is essentially the ceramic-insulated center electrode part which is exposed to the combustion chamber, can be made of AIN as a continuation of the part above it just described, but protected from surface erosion by specific AIN formulations, or by coating(s), treatments, or other techniques. Or this lower is part may be made of various aluminas which have enjoyed nearly a century of development into a formidably effective spark-plug insulating material, but lacking AIN's superior heat conductivity. The ceramic joint between the AIN and A1203 parts would typically be a functionally graded composite of the two materials to avoid internal stresses by eliminating abrupt changes of thermal coefficients of expansion, as needed.

Obviously, the entire dielectric structure of the present invention may be made of the many formulations of alumina which have dominated spark-plug insulation until now, without undue challenge to the heat removal objectives.

The inventive center electrode shape (cf. FIG 12-14) promotes two important operational objectives for the direct injection fuel injector part: superior cooling of the fuel injector nozzle valve assembly due to its completely recessed positioning within the cooling spark plug shell as illustrated; and positioning of the fuel spray plume to pass optimally near the spark gap, achieving the combustion efficiency benefits of so-called "spray-guided gasoline injection", permitting direct and immediate ignition of the spray plume, thus avoiding complicated fuel vapor paths with their disavantageous ignition proccess and unwanted combustion chamber wetting and cooling (cf. FIG 2, 3). At worst, the fuel injector need not extend into the combustion chamber substantially farther than the grounding spark electrode (cf. FIG 4, 5), for the purpose of minimising heating of the fuel injector part by the combustion proccess, and minimising detremental shielding of the spark gap(s) from exposure to the fresh fuel-air mixture, and quenching of the expanding flame front, by the fuel injector part. No thermal coating should be needed for the fully recessed fuel injector (cf. FIG 2, 3).

In the examples of the present invention, said fuel injector is operated by the mechanically simplest method of controlled fuel pressure, wherein the fuel itself performs double duty as a hydraulic valve lifting agent, requiring an unspecified internal (integral) or external (discrete) injector fuel metering valve means depending on the application (cf. FIG 15 -20 -internal piezoelectric means). In the most high performance examples, either an integrated or separate piezoelectric actuated high speed high pressure fuel metering valve may connect the said fuel injector nozzle to a high pressure fuel reservoir, termed a fuel rail, enabling an almost instantaneous injection pressure rise to the fuel rail pressure. In the absence of a residual pressure discharge control valve as part of the io metering valve system (cf. FIG 19, 20), when the piezoelectric fuel metering valve is switched closed (cf. FIG 18-A), the pressure between said metering valve and the nozzle valve falls by a pressure bleed-off proccess (via the fuel injector's nozzle valve being held open so long as residual pressure holds it open -cf. FIG 18-B) below the nozzle valve spring biased opening pressure, which pressure should be maintained to exceed the is boiling vapour pressure of the fuel at the operating temperature of the fuel injector. When such a residual pressure discharge control valve is provided (cf. FIG 18-C, D), provision should be made in the case of liquid fuel to prevent the pressure from falling below said fuel boiling vapour pressure by means of less desirably a flow restrictor and/or more desirably a pressure regulated intermediate vessel for the fuel returning from the residual pressure discharge control valve to the fuel tank, which may be regarded as an outflow fuel rail maintained at a regulated pressure above said fuel boiling vapour pressure, which in turn empties into the fuel tank. In the case of gaseous fuel, which is problematic to inject precisely without aid of a residual pressure discharge control valve, due to its compressibility, the simplest means of dealing with the discharged excess fuel, minimizing waste and pollution, would be to discharge this fuel into the intake manifold of the internal combustion engine, employing engine regulation controls to manage the correct air to fuel ratio, etc. In the absence of said residual pressure discharge control valve, the rate of said pressure bleed off decreases with the amount of compressive energy stored in the fluid volume contained between the metering valve (inlet) and the nozzle valve (outlet). This energy increases with both the compressibility of the fuel and its occupied volume, which implies that in response to the closure of the fuel metering valve feeding into a relatively small diameter and relatively short fuel channel connecting to the nozzle valve, said channel pressure will drop relatively more quickly, eliminating need of a residual pressure discharge control valve to attain the required fuel spray cutoff speed. But a relatively large fuel channel volume following the fuel control valve will require a relatively long time for its stored presure to drop below the injector nozzle valve closing pressure, extending the injection cycle and thus creating an injector response speed limit (cf. FIG 18-B). The remedy would be a residual pressure discharge control valve to discharge the excess pressure at the moment the metering valve closes (cf. FIG I 8-D) to avoid a pressure bleed off delay during fuel injection, and thus eliminating this injector response speed limit (cf. FIG 18-C). Therefore an inventive compact and simple high-speed fuel metering valve optimally based upon the same inventive Belleville spring principle as the nozzle valve (in principle amenable to any kind of spring) inventively coupled with an inventive high-speed residual pressure discharge control valve using the same compact spring principle is io provided in the present invention for application in case of need, the use of which is not limited to the present invention, but of universal application. The inventive residual pressure discharge control valve is prepared in reserve to guarantee performance in case of need, and may be incorporated internally within the spark plug, or separately and externally, along with an external metering valve in possible combination with a residual is pressure discharge control valve, for example.

Thus said fuel injector should provide superior performance due to its unmatched high speed and injection frequency advantage. Thereby the invention's examples are able to enjoy the uncompromised benefits and technologies of the state of the art long-life globally dominant 14mm spark plug requiring very minor modification from its normal configuration, such as in the simplest case of adapting the fuel connections (either by a swiveling fuel inlet collar or by the considerably simpler means of indexing by using calibrated spark-plug washer thicknesses, or both in combination) and channels to its threaded outer steel shell (cf. FIG 1) to operate the fuel injector installed at the spark plug tip adjacent to the modified spark electrode configuration. Considering the radially non-symmetrical aspect of both the spark gap and the fuel injector, as well as the considerable added complexity of including a swiveling fuel coupling, the indexing solution for threaded mounting of the present invention in preferance to use of the swiveling coupling would probably be preferred where possible for the variant of Fig 1, as well as for FIG 21 and 22.

Obviously, threadless mounting methods, using clamps, which dominate modern fuel injector mounting, are applicable to all variants of the present invention.

An example of an embodiment of the present invention joins a fuel injector according to application PCTIEF2OIOIO6I79O to the standard 2mm wide annular cross section surface of the 12mm outer diameter standard threaded cylindrical portion of the standard 14mm spark plug, either not extending beyond the normal end of the standard 3s 14mm spark plug, or in the worst case about 3mm beyond its end. A configuration of the fuel injector (limited to a nozzle valve assembly) designed by finite element analysis mathematical modeling methods fits in a housing idealized as a circular cylinder 3.5mm high, of 5mm inner diameter and 6mm outer diameter, although in an example of an embodiment of the present invention the outer surface is 6mm across only at its narrowest point, having an almond or eye shaped outer cylindrical profile. The central axis of the spark plug is exactly tangent to the outer surface of the idealized 6mm cylinder. In other words, the fuel injector extends no further than to the midpoint of the spark plug cross section, and from the end view shields less than 113 of the central cavity of the spark plug from direct exposure to the combustion chamber, facilitating burning away of carbonization. The area of vital cooling interface contact between thefuel injector and the io spark plug housing in direct contact with the cylinder head by its threaded portion is in excess of the exposed end surface area of the fuel injector, in its fully recessed, or embedded configuration, constituting a massive and effective heat sink for the fuel injector.

The design of examples of embodiments of the present invention are intended to is balance the competing objectives of providing both sufficient cooling of the fuel injector at the end of the spark plug to prevent overheating, as well as sufficient heating of the center electrode of the spark plug to prevent carbonization, fouling, and misfires, along with good spark gap exposure to the combustible gases with minimal flame quenching.

The ability of the fuel to cool the fuel injector may be exploited not only for the benefit of cooling the injector nozzle valve assembly, but also for a proven combustion benefit of enhanced fuel vaporization through heating the fuel, which is dramatically pronounced in the phenomenon of flash boiling of the vapor plume immediately following injection. The ultra small size of the fuel injector maximizes the ability of the fuel flow to cool this miniature structure, due to the minimal mass to be cooled. Maintaining high minimum fuel pressures within the fuel injector in excess of the fuel vapor pressure at its operating temperature counteracts the disruptive effects of fuel boiling. Superheating the fuel to temperatures approaching 300°C under pressure has been demonstrated in theoretical and practical studies to flash vaporize the fuel spray after injection, depending on the mode of operation and cylinder pressure, resulting in near total combustion of the fuel, maximizing fuel efficiency and minimizing pollutants, including nitrous oxides, which is certainly a realizable design objective of the present invention, which may be enhanced by inclusion of a temperature sensor within or near the fuel injector to optimize microproccessor control of the superheated fuel injection process.

By offering higher fuel injector operating speed, frequency, and precision than the state of the art, and both inward opening multi-hole type injector nozzles as well as outward opening poppet valve type nozzles, the present invention supports the goals and conclusions of Chapter 3, Flow, Mixture Preparationand Combustion in Four-Stroke Direct-Injecton Gasoline Engines by Ando and Arcoumanis in Flow and Combustion in Reciprocating Engines, Arcoumanis & Kamimoto eds., Springer-Verlag 2009: 5,,Another thermodynamic effect which can change significantly the fuel distribution at the nozazle exit and the resulting spray structure is flash boiling, a phenomenon occurring when the fuel temperature is high at high fuel temperatures and low ambient pressures, the individual sprays are rapidly atomized to such a degree that it becomes impossible to distinguish the spray plumes; although flash boiling is highly io desirable from the atomization point of view, it can only take place within a very narrow window of engine operating conditions and it is not considered important as an atomization mechanism. However, in relative terms, it can be argued that the effect of flash boiling is much more pronounced in the sprays generated by multi-hole rather than pintle injectors. ... Although experiments in single and multi-cylinder engines employing is multi-hole injectors have been promising, t is widely accepted that further refinement of their design is needed to ensure stable ignition and combustion with acceptable gaseous and particulate emissions. Faster opening and closing times combined with much higher than today's injection pressures may make multi-hole injectors directly comparable to the piezoelectric outward-opening pintle-type injectors that, at present, seem to be the preferred fuel injection system.' The high speed fuel injection potential of the present invention offers a possibility to control and conquer the above mentioned,,very narrow window of engine operating conditions" in which flash boiling atomization is possible, resulting in the ultimate conditions for maximum fuel efficiency and power with minimizing of harmful exhaust emissions for both two cycle and four cycle direct injection gasoline engines.

In order to effectively apply the flash boiling principle to the present invention, besides the obvious heat of combustion to contribute to such flash boiling, it would appear that the flash boiling temperature would need to be regulated between a minimum temperature to insure the flash boiling effect to vaporize the injected fuel plume immediately after injection, and a limiting maximum temperature, because flash boiling within the fuel injector would generally need to be avoided to preserve the incompressibility of the injected fluid medium which insures the speed and precision of the injection process. Also, maintaining a minimum internal fuel pressure to oppose flash boiling within the fuel injector at least during the injection process and preferably 3s continually, would be needed. A part of the solution to this problem would be to employ controlled fuel heating sources to maintain the correct injected fuel temperature, of which the most obvious is a thermostatically controlled electrical heating element, used in conjunction with heat sensor(s) and well-known electronic controls. And fuel pressure regulation would need to be applied either by simple static means of maintaining a sufficiently high fuel rail pressure, or by more complex, even dynamic means, well known to the various arts.

By virtue of the unprecedented compactness of the nozzle valve, the open, uncluttered structure of the various embodiment examples of the present invention affords plenty of space for installation of a flash-boiling injection system, and the location of the io nozzle valve assembly at the tip of the igniter -injector, especially in its fully embedded configuration, affords the necessary cooling control ability to limit the flash boiling temperature to under 300°C or any other foreseeable flash-boiling working temperature, while at the same time affording flexibility to add thermostatically controlled heating elements to maintain the flash boiling temperature lower limit. There is physical space is available near the tip of injector-igniter, within its threaded mounting cylinder and in the immediate vicinity of the nozzle valve assembly to include a temperature sensor and/or heating element, namely in combination with the fluid medium channel leading to the nozzle valve assembly, enabling electronically regulated fuel temperature of the controlled pressurized non-boiling fuel immediately prior to injection to insure flash boiling of the injected fuel plume immediately after injection. Pressure sensing for pressure management within the nozzle valve could be managed outside of the area of the preferably threaded mounting cylinder of the injector-igniter.

Although there may be a possible benefit in the preceding description of thermostatically controlled heating the fuel immediately before injection within the threaded mounting cylinder, injection being defined as the fuel in its flash boiling spray plume condition after it has left the nozzle valve assembly, it is more convenient, and will likely be necessary, to heat the fuel in advance of the threaded mounting cylinder, affording the advantage of more volume for both fuel and temperature regulated electronic fuel heating element(s), possibly in combination with engine heat sources, which could be used in combination with a regulated heating element within the threaded mounting cylinder, or without such combination. Heating of fuel within the neccessarily small volume of the fuel channels in the injector-igniter poses the problem of residual heating element heat boiling the fuel between injection pulses when it does not flow.

A BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be more fully understood from the description of examples of embodiments of the invention set forth below, together with the accompanying drawings wherein the relative proportions and scale of any drawing is based on the shown threaded mounting cylinder being identical to that of a standard 14mm spark plug: Drawing FIG 1 is a sectional view of a spark plug having an integrated fuel injector which consists of the nozzle valve function only, which is fully recessed into its threaded mounting cylinder, wherein the fuel injection metering function is external, and not shown.

Drawing FIG 2 is an enlarged sectional view of the tip of the spark plug of FIG I showing an outward opening nozzle valve.

Drawing FIG 3 is an enlarged sectional view of an alternative tip of the spark plug of FIG I showing an inward opening nozzle valve, which is also depicted in FIG 21 and 22.

Drawing FIG 4 is an enlarged sectional view of an alternative tip of the spark plug of FIG I wherein the inward opening fuel injector nozzle valve is not recessed into its is threaded mounting cylinder. Also, the fuel injector illustrates an optional outer layer of ceramic thermal insulation.

Drawing FIG 5 is like FIG 4, except that the spark gap extends further into the combustion chamber, and the optional outward opening nozzle valve is illustrated.

Drawing FIG 6 is a magnified sectional view of an outward-opening opening nozzle valve assembly depicted as a separate module, although its housing may be machined of one piece with the spark plug shell.

Drawing FIG 7 is a magnified sectional view of an inward-opening opening nozzle valve assembly depicted as a separate module, although its housing may be machined of one piece with the spark plug shell.

Drawing FIG 8 illustrates sectional and end views of a fuel supply coupling collar from FIG 1, or when axially elongated, pertaining to FIG 24, allowing free rotation of the spark plug without rotating the fuel connection.

Drawing FIG 9 shows a bottom end view, including a dashed X-ray spring cavity outline view, of the spark plug of FIG I or 24 employing the non-recessed nozzle valves of FIG4or5.

Drawing FIG 10 shows the bottom end view of the more advanced, fully recessed nozzle valve design of FIG 1,21, and 22.

Drawing FIG 11 is like FIG 10, except it shows an elevation contour plot of the tip of the spark plug center electrode, revealing how it more or less wraps around the nozzle valve assembly housing. FIG 11 corresponds to the wire frame views of FIG 13 and 14, and to the heat range sequence item FIG 12D.

Drawings FIG 12 B, C, D, and E, show in a geometric progression the heat range sequence respectively from cold to hot of the geometrical structure of the innovative central electrodes for the fully recessed fuel injector embodiments of FIGs 1, 21, and 22.

FIG 12 B-F are are side x-ray shadow outline views with their corresponding end views showing topographical elevation outlines. FIG 12 A is a sectional side view rotated 90° io with respect to side views FIG 12 B -F, showing a typical corresponding end view (from FIG 12 D).

Drawing FIG 13 is a three-dimensional wire-frame side view of the tapering end of columnar insulator which is exposed to the combustion chamber, showing how its conical upper shape like that of a normal spark-plug varies along its axis, becoming indented to is make room for the fuel injector.

Drawing FIG 14 is an end, axis centered view of the columnar insulator of FIG 13, the axis being that of the conical upper structure and of the entire spark plug. Note that the same contours as in FIG 11, 12 D, and 13 are shown.

Drawing FIG 15 is a functional schematic diagram of the inventive piezoelectric fuel injector metering valve system in its not-energized, shut-off state, which incorporates a residual pressure discharge control valve to eliminate pressure bleed off delay after the piezoelectric element is de-energized to close the valve and stop the fuel injection.

Drawing FIG 16 shows the same piezoelectric metering valve system schematic as in FIG 15, except that the valve is shown in its energized, open state, causing fuel injection by the fuel injector nozzle valve.

Drawing FIG 17 is a composite, ,,dynamic" view of both FIG 15 and FIG 16.

Drawing FIG 18 A, B, C, and D shows a synchronized series of timing diagrams illustrating the operation of the dynamic metering valve action depicted in FIG 17, wherein FIG 18 A shows the position of the metering valve. FIG 18 B plots the fuel pressure in the situation where the residual pressure discharge control valve is not present, showing an extended fuel injection bleed off after the piezoelectric metering valve shuts off. FIG 18 D shows either fuel flow or fuel pressure at the outlet of the residual pressure discharge control valve. And FIG 18 C shows the fuel flow or fuel pressure at the input to the fuel injector nozzle valve benefitting from the action of the residual pressure discharge control valve, stopping the injection as soon as the metering valve shuts off.

Drawing FIG 19 shows the schematic diagram of the inventive piezoelectric metering valve system wherein a residual pressure discharge control valve is not needed, corresponding to FIG 21 -23.

Drawing FIG 20 shows the inventive piezolectric metering valve of FIG 18 in a composite, dynamic split view, showing said metering valve in both open and closed states.

Drawing FIG 21 shows a completely integrated piezoelectric fuel injector with a spark-plug, where the high voltage connector is at the top, and the fuel injector metering control connector is at the side.

Drawing FIG 22 shows a completely integrated piezoelectric fuel injector with a spark plug, where the fuel injector metering control connector is at the top, and the high voltage connector is at the side.

Drawing FIG 23 shows an enlarged view of the inventive metering valve mechanism and the internal high voltage connection to the spark-plug tip part of F1G 21 AND 22.

Drawing FIG 24 shows a stretched, standoff version of the swiveling fuel inlet collar arrangement of FIG 1 and FIG 8, to provide better access, which is self-explanatory.

Drawing FIG 25 shows Belleville spring corrugation shapes designed to minimize spring internal stress.

Nearly all of the examples of embodiments of the present invention are either illustrated in the drawings, or by refefence to the drawings, which do not show every combination of features, to avoid needless duplication.

INTRODUCTION TO DETAILED DESCRIPTION OF EXAMPLES OF EMBODIMENTS

The most fundamental inventive step of the present invention, namely it's segregated placement of a complete basic fuel injector embodiment into the very tip of a spark plug, solves the technichal problems arising from past attempts at physical integration of the competing ignition and injection functions, if not compromising one or the other or both basic elements of the injector-igniter combination, making the technical solution ineconomical. The key to this segregation solution was miniaturization of the fuel injector function in its most elementary embodiment as a nozzle valve assembly based upon inventive application of the parallel Belleville spring stack, herein embodied as spring assembly 20, to achieve miniaturization not only without performace compromise, but with forseeable fuel injector performace gain.

Among other advantages, miniaturization of the nozzle valve assembly boosts the effectiveness of the spark plug cooling system dissipating heat into the cylinder head through the preferably threaded mounting cylinder of the spark plug which the fuel injector shares, as well as boosting the relative effectiveness of the cooling effect of fuel flowing through the fuel injector fluid medium channel(s), which in comparison to the state of the art remains constant while the fuel injector requiring cooling has been reduced in io mass and heat absorbing surface area by one or more orders of magnitude. Nozzle valve miniaturization enables the unprecedented placement at the entire nozzle valve at the tip of the spark plug, removing the intrusive mechanical and electrical presence of the fuel injector from nearly the entire state of the art spark plug structure which may thereby enjoy without physical intrusion or functional compromise the benefits of over a century of is technological advances of the spark plug art which have refined and enriched the capabilities of that well-proven sturcture, the features of which are preserved in the present invention to a degree unprecedented in prior art attempts to create a unified injector-igniter.

Without limitation to the following examples, the present invention combining a spark-ignition device with a fuel injector, (henceforward,,injector-igniter") is offered in two basic types of embodiments having much in common: the one using an separate (discrete) fuel metering unit, and the other using an internal (integral) fuel metering unit.

The first embodiment type is very nearly identical to a standard 14mm spark-plug, due to the minimal adaptation neccessary to incorporate an effective fuel injector according to patent application FCT/EF2OIO/061790, wherein an external fuel metering valve system either according to variants FIG 15 -20, or according to any other suitable art, past, present, or future, are required for its operation. And the second basic type of embodiments of the injector-igniter incorporate practically all of the features of the first type, but discarding its fuel supply connecting collar, and incorporating the fuel metering valve system variants according to FIG 15-20 into an enlarged body of the injector-igniter wherein the injector-igniter of the version just described is essentially split in two just above its classic driving hexagonal, wherein said metering valve system variants according to FIG 15 -20 are inserted between. Both types find their optimal applications under contrasting technical requirements. In the detailed description, only parts and qualities which are distinct from the universal 14 mm spark plug stadard will be explained.

Application of the present invention to other spark plug sizes and standards will be obvious to the artisan.

And also, notwitstanding the current advantages of fuel rail based piezoelectric fuel metering favored in the examples, fuel metering technologies based on older and often simpler and cheaper mechanical or electromechanical means are often a more preferable solution to fuel metering where the engine or fuel type being served is not capable of benefiting by piezoelectric technology or for any other reason. So wherever a piezoelectric fuel metering actuator or system is illustrated or mentioned, application of non-piezoelectric types are implied and encouraged for use with the present invention, and their example is by no meants a limitation of the claims of this patent.

Although application of non fuel rail metering systems are not illustrated herein, such application is obvious to the artisan, particularly in view of the embodiment of FIG 1, where no specific metering means is suggested, and any may be applied.

The present invention is also divided into two of fuel injector nozzle valve positionings with dramatic differences in the geometry of the central electrode and is technical and economic benefits: attachment of the nozzle valve body to the end surface of the spark-plug, so that it extends into the combustion chamber, leaving the spark-plug practically unchanged from its classic original form; and complete recessing of the nozzle valve body into the spark-plug shell, so that both of their end surfaces are more or less in the same plane. All intermediate relative nozzle valve positioning and consequent central electrode geometry variations as well as deeper recessing, being obvious hybrids of the two extremes, are also claimed by the present patent. The fully recessed variation is clearly the most interesting and technichally promising, but the more primitive non-recessed variation is advantageously more simple and economical to make, and may be a superior choice for less demanding applications. Again, all aspects of every variation of the present invention are completely interchangable, variable, and blendable, and protected by the present patent, though not specifically illustrated due to limits of space, but not of claims.

The invention according to PCTIEP2OIOIO6I79O achieves miniaturization of the fuel injector while at the same time not merely preserving state of the art performace, but increasing it by virtue of both the miniaturization and simplification due to its structural features and great reduction of the mass of moving parts. Therefore the reader is referred to PCT/EP2OIO/061790 for any details concerning this fuel injector. Details fundamental to the fuel injector, fuel metering valves, and piezoelectric stack biasing, alignment, and centering spring system applicable to the present invention are available in The reader is also advised that PCTIEP2O1OIO6I79O, which applies to the present invention, offers six distinct examples of inward-opening nozzle valves, and basically one example of an outward-opening nozzle valve, but minor functional differences which may present significant choices in certain applications at least double that number for both categories. All of these variations of nozzle valves, most of which are not shown in the present document, are options for applicable categories of embodiments (eg. inward" or outward" opening nozzle valve categories) of the present invention.

Because the same identical principles of operation of the poppet nozzle valves of FCTIEF2OIOIO6I79O apply to poppet control valves, patent protection is applied for in the io present document for the poppet control valve application. Because poppet control valves, and more specifically high-pressure poppet control valves are most usefully outward-opening opening poppet valves wherein the direction of fluid flow is reversed from that in the respective nozzle valves, inward-opening control valves will not be specifically discussed in the present document.

Because variants of the injector-igniter have many parts or elements in common, those elements may be described only once, at their first appearance in the flow of the descriptions in the order of the drawings below, generally without repeated description at their repeated appearances in subsequent embodiments.

In the following descriptions of drawings of diverse embodiments, generically identical details and elements are designated with identical reference numbers.

DETAILED DESCRIPTION OF EXAMPLES OF EMBODIMENTS

The present invention is further described from the description of examples of embodiments of the invention by generally sequential reference to the accompanying cross-referenced and interrelated drawings, wherein the relative proportions and scale of any drawing is based on the shown spark plug threaded mounting cylinder being identical to that of a standard 14mm spark plug (eg. FIG 1).

In the following descriptions of drawings of diverse embodiments, generically identical details and elements are designated with identical reference numbers.

Drawing FIG I illustrates by a sectional view a generally radially symmetric spark plug, in this embodiment being a nearly standard 14mm spark plug, having an integrated miniature but fully capable outward-opening fuel injector, which for FIG iconsists of the nozzle valve function only, embodied as nozzle valve assembly 1 fully recessed into the combustion chamber penetrating tip of the spark plug's (preferably and normally threaded) mounting cylinder 2 conforming to the 14mm spark plug standard, inventively sharing the space normally solely occupied by the normal ceramic-insulated center electrode 3 by means of an inventive configuration of said center electrode 3 to be described later. Said center electrode 3 shares its spark gap 4 with a side electrode 5 (one or more) mechanically and electrically connected to (preferably threaded) mounting cylinder 2 of a metallic (not limted to metallic) shell 6. The housing shell 6 in turn comprises besides the said threaded mounting cylinder 2, a cylindrical seating portion fitted with (enclosed within) a swiveling fuel inlet collar 7 (detailed in FIG 8) and topped by its driving hexagonal 8; which housing shell 6 houses/supports a columnar insulator 9 having a standard spark io plug male connector configured at its upper end, encasing a mostly cylindrical metallic (non-limiting -eg. may be conductive ceramic or ceramic composite) central electrode 2 typically of 2.5mm diameter along with its electromagnetic interference suppression resistor typically near the middle along its length (not shown).

The neccessary fuel injection metering function (eg. metering pump or metering is valve system fed by a high-pressure fuel rail) is external, and not shown.

The materials, sealing, and construction of a normal 14mm standard spark plug, including its many modern variants, with which the present invention may be practically identical, will not be recited, as this is the most common global standard, and is almost entirely applicable to the present invention, but in no way limiting to it. Only neccessary departures from aspects of the normal spark plug will be described.

FIG 1, as detailed, expanded and subdivided into variant sub-examples, and clarified by FIG 2 -14, and functioinally described by operational schematic diagrams FIG -20 illustrates an injector-igniter example which is discrete from its neccessary but unspecified and unlimited fuel metering system, which fuel metering system is not limited to comprising a fuel rail or a valve system as indicated in the drawings. The disposition and arrangement of the fuel injector part, the central electrode tip part, and the spark gap involve inventive steps attaining technichal advances with economical advantages, (as likewise applied to the examples of FIG 21 and 22).

Fuel flows into the fuel inlet collar 7 (the view of FIG 1 is elaborated in FIG 8) by its angled collar inlet pipe 10 from an unspecified fuel-metering system on the left, and channeled as shown under the collar inner gasket seat 11 of the spark plug into an collar annular groove 12 in the seat of the collar, (see end view in FIG 8). From this lower collar annular groove 12 which may also function as a sediment trap, the fuel flows upward through holes or pores an annular sealing washer 13 typically of copper, into an upper inlet annular groove 14 in the spark plug seat 15, indicated in side view cross-section by the notches just above the sealing washer 13. Having passed through the copper sealing washer 13 filter into the inlet annular groove 14 in the spark plug housing shell 6, fuel flows by way of the right angled holes of fluid medium channel 16 longitudinally downward through the cylindrical wall of the spark plug threaded mounting cylinder 2 into the nozzle valveassemblyl.

An axially elongated version of fuel inlet collar 10 is shown in FIG 24, for the purpose of providing axial offset from the surface of the mounting seat of the injector- igniter, which provides convenience of connection and maintenace access to the injector-igniter.

Although this sealing washer 13 is not otherwise illustrated, it may be of two types, one of them novel. The ordinary type allows fuel to pass through by means of one or more holes around its circular extent. The novel type serves as a fuel filter as well as a gasket, by having a sealing radially outer copper ring, and a sealing radially inner copper ring, and a porous ring of filter material between the former two, which could be made of is sintered copper powder, or other porous filtering material.

Chamfer 17 in the side sectional view of FIG I will be introduced in the description of end views of FIG 9, 10, and 11, which will refer back to the side sectional views of FIG 1 -5.

Gas flow point 18 represents an arbitrary point on the surface of the central electrode insulator wherein gas flow point 18 is in freely replenishing gas communication with (ie. exposure to) the combustion chamber. This means that there is cycle by cycle replenishing gas circulation at such a surface point on the insulator at a minimum, and that each combustion cycle is able to provide sufficient fresh hot combustion gas to such a point to the extent that fouling of the spark plug is avoided, and/or normal operation of the spark plug is maintained. Such a surface point is a measure of access of the hot gases of the combustion chamber to the same axial level (level along the spark plug axis) of any point on the fuel injector nozzle valve assembly's valve closure element or part of its valve spring assembly. This condition limits and challenges fuel injector nozzle valves having long pintles and/or valve springs which extend farther away from the combustion chamber than in the present invention, and is therefore a measure of the uniquely advantageous miniaturization and location of such fuel injectors nozzle valve assemblies.

It is argument of the present invention that this condition uniquely characterizes the miniaturization and functional technical advantages of the present invention, setting it apart from the state of the art.

Drawing FIG 2 illustrates by an enlarged sectional view the tip embodiment example of the spark plug of FIG I (& 24) showing in detail its outward opening nozzle valve I and its reference numbered parts 1, 3, 4, 5, 17 and 18 previously discussed for FIG 1, which is interchangable with the inward-opening nozzle valves 1 (cf. FIG 3) of the embodiment examples of FIG 21 and 22 to suit design requirements. The end views corresponding to FIG 2 are FIG 10 and 11.

Drawing FIG 3 illustrates by an enlarged sectional view an alternative tip embodiment example applicable to the spark plug of FIG I (& 24), having an inward opening nozzle valve, and which is also depicted in FIG 21 and 22, showing the identical io or comparable reference numbered parts as in drawing FIG 2. Its corresponding end views are FIG 10 and 11.

Drawing FiG 4 illustrates by an enlarged sectional view an alternative tip embodiment example of the spark plug of FIG 1 wherein the inward opening fuel injector nozzle valve is situated on the end surface of the threaded mounting cylinder 2, rather is than being recessed into it, and the central electrode having a nearly conventional circular cross-section conical shape, excepting its extreme tip, which has a simple tilted conical shape. It shows the same reference numbered parts as described in the previous two examples. Its corresponding end view is FIG 9. The difference of this example from that of FIG 3 is that its fuel injector nozzle valve assembly I is more exposed to the combustion chamber heat and therefore its end view, FIG 9, compensates for this added heat exposure by increasing contact with its cooling threaded mounting cylinder 2 in comparison with the embodiment of the end view FIG 10 which corresponds to FIG 3. In contrast to the embodiment of drawing FIG 3, it's fuel jet trajectory is not directed towards the spark gap, requiring a more complex and longer duration injection and ignition timing strategy. Balancing the score of these limitations, however, the present example offers advantages in that the center electrode may be made of parts which are entirely cylindrical, permitting simpler traditional spark plug insulator manufacturing and assembly methods to be used, where the parts are manufactured separately and assembled afterewards. Also, this fuel injector nozzle valve assembly I of FIG 4 illustrates an optional thermal insulating barrier 33.

Drawing FIG 5 illustrates an example embodiment like that of FIG 4, except that the spark gap extends further into the combustion chamber, and the optional outward opening nozzle valve is illustrated, whose outside dimensions are identical to those of the inward opening nozzle valve, excepting at the obvious tip. The same reference numbers, comments, and observations as for drawing FIG 4 apply.

Drawing FIG 6 illustrates by a magnified sectional view an inward-opening opening nozzle valve assembly I (a minimal complete fuel injector) example embodiment depicted as a separate module, although its housing may be machined of one piece with the preferably threaded metallic mounting cylinder 2. In either variant a disc-shaped valve end disc 19 is installed sealing up the moving parts of the nozzle valve assembly I in its cylindrical cavity, which moving parts include its peripheral edge to cavity wall contact-fit spring assembly 20 (which spring assembly comprises the entire Belleville spring stack including all of its spacer elements described below), and its inward-opening or outward-opening valve closure element 21 as the case may be. Of course, the nozzle valve io assembly I housing may be made as a separate module of any advantageous material, such as metal or ceramic, for example, and joined by brazing, laser welding, or other techniques to the spark plug threaded shell 5, as suggested by the drawings. A sealed factory adjustment hole just above the top end of the stem-shaped part 22 of the valve closure element 21 for its final precision fluid-tight factory adjustment, if needed, is not shown, but mentioned to suggest how such final factory adjustment may be done.

All of the examples of the present spark ignition device structurally integrated with a direct-Injecton (Dl) fuel injector into a common rigid structure (injector-igniter) for an internal combustion engine depict its nozzle nozzle valve assembly 1, wherein said nozzle valve assembly I is at least by its end surface 23 intended to be in immediate communication with an internal combustion engine combustion chamber.

In all examples, a spring assembly 20 comprising Belleville springs 24 with their spacer elements to be described below, is placed within the injector nozzle valve assembly I precision close-fitting cylindrical cavity along with valve closure element 21 which is held precision aligned and centered to its valve seat 25 by spring assembly 20 (a spring assembly comprising both springs and spacer elements, generally washers).

The nozzle valve assembly I comprises a fluid medium channel 16, the valve seat and the valve closure element 21, and the spring assembly 20 of Belleville springs 24.

Belleville springs 24 of the spring assembly 20 of the nozzle valve assembly I are depicted in their biased state (cf. FIG 25), which will be discussed more fully below.

The axes of the individual stacked Belleville springs 24 coincide with the axis of of what is commonly termed as its stack (i.e. spring assembly 20).

Valve closure element 21 is pressed by the biased spring assembly 20 against valve seat 25, and valve closure element 21 is aligned with respect to the valve seat 25 axis by means of said spring assembly 20.

Valve closure element 21 comprises at least one fluid medium channel 16. Other fluid medium channels 16 are not depicted in the interests of clarity. These comprise channels for conducting a fluid medium between the Belleville springs 24 and other fluid medium channels 16 which would be required in actual embodiments.

FIG 6 has the Belleville springs 24 of its spring assembly 20 depicted as conical shapes with flat inner and outer rims, which support the stack of the spring assembly 20.

This is generally a fiction for convenience of drawing, although it is technically possible to design a corrugated BeIlevilIe spring which could assume such a shape under compression. In reality, the Belleville springs of FIG 6 are symbolic of a realistic and practical class of optimized Belleville spring 24 shapes shown in drawing FIG 25 (to be io discussed below). The Belleville springs 24 of the spring assembly 20 may have an annular wave-shaped corrugation (FIG 25) symmetric about the central axis of Belleville spring 24. Moreover, classic Belleville springs 24 without corrugation according to drawing FIG 25 may also be used. When classic Belleville springs are compressed, they assume a shape suggestive of an annular corrugation. But by definition, ,,corrugation" applies to is the relaxed, and not to the compressed shape.

As can be seen from all of the preferred embodiment drawings FIG I -7, 16, 17, 19 -23 (including not merely the Belleville spring assemblies 20 of the nozzle valve units I but the spring assemblies the nozzle control valves and of the piezoelectric stack yet to be discussed as well) the Belleville springs 24 of the inventive nozzle valve assembly spring assembly 20 are arranged in a stack in the same orientation. Thus in the interest of compactness, they are not employed as Belleville springs 24 stacked end to end in "series stacking" (each successive pair oriented as mirror images), but rather as stacked side by side in "parallel stacking" . Optimal frictionless operation of the parallel stacking arrangement is achieved by use of respectively outer and central spacer elements (generally washers) 26 and 27 between successive pairs of Belleville springs 24.

Thereby, in the case of identical Belleville springs 24, the force of each Belleville spring 24 is multiplied by the number of Belleville springs 24 in the stack.

All examples of the present invention nozzle valve assembly 1, as well as the completely analogous control valve assembly of FIG 23, applicable in principle to the schematic diagrams FIG 15 -20, (and finally even to the piezoelectric stack of FIG 23, to be discussed below), comprise stacked BeIleville springs 24 in their spring assemblies 20, in which between every two sequential Belleville springs 24 are two spacer elements 26 and 27 (respectively peripheral and central), most often embodied as respectively peripheral and central spacer washers 26 and 27, wherein spacer element 26 is situated between two outer support areas 28 of the Belleville springs 24, and wherein the other spacer element 27 is situated between two central support areas 29 of the Belleville springs 24. Belleville springs 24 are typically held separated from each other by spacer washers 26 and 27 serving as spacer elements to avoid friction. Instead of respectively peripheral or central spacer washers 26 or 27, annular thickening 26 or 27 of the Belleville spring outer or central support areas (respectively 28 or 29) may serve respectively as spacer elements 26 or 27 in cases where relative radial freedom of movement between the spacer elements and the Belleville springs for centering adjustment of the valve closure element 21 in its valve seat 25 is not intended or not possible due to the installation. In general, depending on the context, the respectively peripheral or central spacer elements 26 or 27 may represent either spacer thickenings 26 or 27 or spacer io washers 26 or 27, wherein spacer thickenings 26 or 27 are of one piece with an adjacent Belleville spring 24. For example, spacer thickenings 26 or 27 may be separate spacer elements 26 or 27 rigidly connected to the Belleville spring 24, regardless of their being clearly depicted in the drawings as separate parts, namely spacer washers 26 or 27.

In order to compress the Belleville spring 24 to its said bias region of its force versus is displacement spring characteristic curve, the outer support area 28 of the Belleville spring 24 is displaced by force of outer forcing surface 30 along their axis toward the central support area 29 of Belleville spring 24, which is supported by an equal and opposite force of central forcing surface 31. The two forcing surfaces 30 and 31 subject the spring assembly 20 to compression.

Centering of the Belleville springs 24 in the spring assembly 20 with respect to the axis of nozzle valve assembly I is anchored to the fixed radial position of either the outer supprt areas 28 of the Belleville springs 24, and/or their associated spacer elements 26 wherein either or both of them are in full circular contact with the cylindrical cavity wall of the nozzle valve assembly 1. The outer spacing washers 26 are always in contact with the cylinder, but the Belleville springs 24 may have a radial gap (cf. FIG 6), allowing radial movement of the Belleville springs with respect to their outer spacer washers 26, which clamp the Belleville springs into a fixed radial position after any radial movement of the interleaved Belleville sprimgs by a spring clutch process. The analogous situation holds likewise for the inner cylinder boundary of the spring assembly 20, wherein the central washers are always in full circular contact with the central cylinder boundary which is the stem-shaped part 22 of the valve closure element 21. Here, the central hole of the Belleville springs 24 may have a radial gap with respect to the stem-shaped part 22 (cf. FIG 7), permitting radial adjustment of the interleaved central washers 27 along with their captured stem-shaped part 22, which adjustment is held by clutch force (probably including vibration) of the pressure between the Belleville springs and the central washers 27. This force may be overcome by an adjustement process, or the adjustment may be made with little or no force during the nozzle valve assembly I assembly process.

The Belleville spring 24 directly or indirectly guides and aligns, by the force transmitted by its alignment support point 32 of the central support area 29, the valve closure element 21 precisely into its valve seat 25. The effectiveness or efficiency of this guidance is determined by the relative proximity to the valve seat 25 of the alignment support point 32. As the contact point of guidance along the axis of the valve closure element is moved away from the vaive seat, any imprecision of the guidance is magnified in proportion to this relative distance.

Due to the inventive Belleville spring's directly or indirectly aligning central support io area 29 guiding the valve closure element 21, which includes the decisive condition of alignment support point 32 being as close as possible (the closer the better for both leverage force insuring stable rigidity, and for accuracy) to the valve seat 25 annular sealing surface of the valve closure element (poppet valve) 21, wherein this close proximity, is less than the diameter of a Belleville spring 24 spring assembly 20 (stack) in principle, but in all of the drawn embidiments is considerably less, being in fact less than the valve seat 25 sealing surface diameter in all embodiments of the present invention.

This is another unique aspect of the overall injector nozzle miniaturization in the preferred embodiments. Minimizing this proximity maximizes the stabiiity and mechanical advantage (forces of leverage) which drives the nozzle valve self-aligning function.

In all examples of the present invention the nozzle valve closure element 21 is displaced by pressure of the fluid medium, wherein the fluid medium flows through the central hole of the valve closure element 21, and through other openings in the Belleville springs 18 and openings in the body of the nozzle valve assembly 1 (holes or grooves), which do not appear on the drawings, unto the annular region where the valve closure element 21 contacts its valve seat 25. valve closure element 21 rises microscopically away from its valve seat 25 as the pressure of the fluid medium exceeds the pressure of spring assembly 20, and the flow is forced through the microscopic gap.

The use of multiple stacked Belleville springs 24 enables reduction of the Belleville spring outer support area 28 (the entire stack) diameter in comparison to using a single equivalent performance Belleville spring 24 in the nozzle valve assembly (providing comparable spring performance characteristics). Thereby using several smaller diameter and thinner Belleville springs 24 it is possible to make the nozzle valve assembly as a whole of significantly smaller dimensions (and herein namely the crucially limiting radial dimension, as demonstrated by the narrow 6mm to 8mm diameter nozzle necks of modern fuel injectors, where one is attempting to maximally utilize for multiple circular penetrations the limited surface area at the circular top of an internal combustion engine cylinder) compared to the use of a single Belleville spring 24 of comparable spring characteristics but neccessarily broader diameter in the nozzle valve assembly.

Drawing FIG 7 is a magnified sectional view of an inward-opening opening nozzle valve assembly I depicted as a separate module, although its housing may be machined of one piece with the spark plug shell. This nozzle valve assembly is virtually analogous to the outward opening nozzle valve assembly of FIG 6 just described, with the difference that the spring assembly 20 is reversed in orientation. Otherwise, the preceding descripton of the embodiment example of drawing FIG 6 applies identically with the io identical reference numbers to the embodiment example of drawing FIG 7. It bears noting that the outer forcing surface 30 which is part of the housing of nozzle valve assembly I exerts force against the generally flattened annular outer support area 28 of its adjacent Belleville spring 24 of the spring assembly 20 comprising the alternately stacked Belleville springs 24 and outer and central spacer elements 26 and 27. A single reference line is is likewise employed to indicate the common interface surface of contact between the outer forcing surface 30 and the annular outer support area 28. In the same way a single reference line indicates the common interface surface of contact between the central forcing surface 31 and the central support area 29 of its adjacent Belleville spring 24. The proccess by which the central and outer support areas 29 and 28 become flattened against their respective forcing surfaces and respective spacer washers, where washers are used in conjunction with Belleville springs of uniform thickness, during compression of the springs, is further described in reference to drawing FIG 25.

Drawing FIG 8 illustrates sectional and end views of an axially short cylindrical fuel supply coupling collar from FIG I (which cylinder may be axially elongated -,,stretched" -to suit any convenient access elevation of its fuel inlet connection joined at an illustrative 450 angIe, accompanied by matching elongation of the segment of spark plug it encicles as suggested in FIG 24), allowing free rotation of the spark plug without rotating the fuel connection.

As previously explained for FIG I which presents a more comprehensive view than FIG 8, fuel flows into the fuel inlet collar 7 (the view of FIG I is elaborated in FIG 8) by its angled collar inlet pipe 10 from an unspecified fuel-metering system on the left, and channeled as shown under the collar inner gasket seat 11 of the spark plug into an collar annular groove 12 in the seat of the collar, (see end view in FIG 8). From this lower collar annular groove 12 which may also function as a sediment trap, the fuel flows upward through holes or pores an annular sealing washer 13 typically of copper, into an upper inlet annular groove 14 in the spark plug seat 15, indicated in side view cross-section by the notches just above the sealing washer 1 3. Having passed through the copper sealing washer 13 filter into the inlet annular groove 14 in the spark plug housing shell 6, fuel flows by way of the right angled holes of fluid medium channel 16 longitudinally downward through the cylindrical wall of the spark plug threaded mounting cylinder 2 into the nozzle valve assembly 1.

Drawing FIG 9 shows a bottom end view, including a dashed X-ray spring cavity outline view, of the injector-igniter of FIG I or 24 employing the non-recessed nozzle valve of FIG 4, and except for a slight radial offset of the spark gap, likewise corresponding to 1° FIG 5. Aside from the nozzle valve assembly 1 details (its inner cylindrical cavity outlined as a dashed circle is 5mm diameter), the end view proportions and dimensions of the injector-igniter practically match those of a standard 14mm spark-plug, wherein the outer thread diameter of the threaded mounting cylinder 2 is 14mm, its non-threaded portion being 12mm diameter, its inner hole being 8mm diameter, and its driving hexagonal 8 is being 21mm across the flats. The outermost layer surrounding the eye-shaped fuel injector housing represents a normally ceramic thermal insulating barrier 33. The outermost ring in the diagram matching the periphery of the 14mm screw thread of a standard 14mm spark plug, and the outline of its standard 21mm driving hexagonal, provides dimensional references for the accurately scaled view. As previously discussed in FIG 1, 4, and 5, we find the eye-shaped housing of nozzle valve assembly I bonded to the end surface of or of one peice with the threaded mounting cylinder 2, in the center of which is the center electrode 3 encased and electrically isolated within the ceramic insulation of the columnar insulator 9, with its spark gap 4 between it and the side electrode 5, and where chamfer 17 provides additional high voltage clearance between the center electrode 3 and the threaded mounting cylinder 2. Within the eye-shaped housing of the nozzle valve assembly 1, as its,,iris is the dashed line circle representing its spring assembly 20 (or its cavity), within which is seen the circular outline of the end of the outward opening valve closure element 21 of FIG 5, which may also represent the unseen outline of the inward opening valve closure element of FIG 4, both having in their center the stem-shaped part 22 of the valve closure element 21 shown as a dashed line circle of the smallest diameter. Close beside the latter is seen another small dashed line circle representing the bore of the fluid medium channel 16 which opens into the cylindrical cavity of the nozzle valve assembly 1, which fluid medium would be liquid or gaseous fuel in the present case, and most likely only liquid fuel due to the requirement for best performance that the fluid medium be relatively incompressible to insure precise high speed injection. The eye-shaped geometry serves to minimize insulator and spark gap shielding from the combustion chamber, thus reducing insulator fouling, flame quenching and obstruction of the ignition process, while maximizing cooling contact of nozzle valve assembly (1) with the preferably threaded mounting cylinder (2) and engine cooling system Drawing FIG 10, being very similar to FIG 9, shows the bottom end view of the more advanced, fully recessed nozzle valve assembly I design of FIG 1, 21, and 22, better seen in FIG 2 and 3. Because the nozzle valve assembly 1 enjoys the benefit of much less exposure to the combustion chamber, and much more cooling contact with the threaded mounting cylinder 2, less contact area with the threaded mounting cylinder 2 is io required for cooling, and therefore the,,eye" shape can be made smaller by being more round, having smaller corners and larger corner angles. For the same reason, the nozzle valve assembly has much less need for a thermal insulating barrier 33 as in FIG 9, and therefore it is not shown. The approach of the center electrode 3 to the inner wall of the threaded mounting cylinder 2 is greater than in FIG 9, and therefore chamfer 17 is greater.

is Yet another difference between FIG 9 and 10 is that the fully recessed nozzle valve assembly I is embedded to a depth where mounting threads are present. Such mounting threads may be part of the outside of the housing of the nozzle valve assembly 1.

Therefore the view of FIG 10 indicates that these threads are present as part of the housing of nozzle valve assembly 1, in contrast to FIG 9. The eye-shaped geometry serves to minimize insulator and spark gap shielding from the combustion chamber, thus reducing insulator fouling, flame quenching and obstruction of the ignition process, while maximizing cooling contact of nozzle valve assembly (1) with the preferably threaded mounting cylinder (2) and engine cooling system Drawing FIG 11 is identical to FIG 10, except it shows an elevation contour plot of the tip of the spark plug center electrode shown in FIG 2 and 3, revealing how it more or less wraps around the nozzle valve assembly housing. FIG 11 corresponds to the wire frame views of FIG 13 and 14, and to the heat range sequence item FIG 120. The elevation contour plot of the tip of the spark plug center electrode 3 reveals as in topographical maps how it more or less wraps around the nozzle valve assembly I housing by a crescent-shaped cross section which transitions smoothly from its classic conical center electrode 3 shape and structure at its deeper levels which provides a mechanically robust circular cross section foundation structure, while at the same time enabling a heat range progression (FIG 12 B-E, from cold to hot) of pyrolytically surface cleaning geometries for resisting carbonization and fouling for a succession of different combustion chamber operating temperatures. The eye shape of the nozzle valve assembly 1 corresponding to FIG 2 and 3 has larger corner angles than in FIG 9, which corresponds to FIG 4 and 5, representing a reduction of the end surface area of nozzle valve assembly 1. The ceramic thermal insulating barrier 33 is not needed because of the enhanced cooling and recessed protection enjoyed by the nozzle valve assembly I within the threaded mounting cylinder 2. It's outer edge includes part of the spark plug threads.

The straight lines passing through the tips of the crescent-shaped contours to the center of the sparking cnductor merely indicate the geometrical tapering of the crescent shaped cross-section to a circular shaped cross-section at the electrode tip.

Drawings FIG 12 B, C, D, and E, show a heat range progression respectively from cold to hot of the geometrical structure of the central electrodes for the fully recessed fuel io injector embodiments of FIGs 1,21, and 22. FIG l2Ashows the common side cross-section view of all of the variants B-E (four in all), wherein FIG's 12 B-E show symmetrical X-ray shadow or projection view outlines each turned 90° from their common cross section view, FIG 12A. At the bottom of each viewA-E is an end-view elevation contour view (like in a topographic map) of the respective heat range geometry. At the bottom of FIG 12 A is is shown, as a sample representative end contour view, the view of FIG 12 D, which also correspond to the wire-frame three dimensional views of FIG 13 and 14. Note that the topographic end views at the bottom of each of the views A-E have a dashed circular outer outline which represents the smallest true circular cross section of the conical portion of the columnar insulator 9 in its conical taper. This circle represents the base of the non circularly symmetric shape beyond this axial level toward the combustion chamber. Construction lines in each of the views A-E assist in associating the various contour levels to their respective axial levels in the cross section view A or the x-ray shadow views B-E. Also, by comparison with FIG 11, it can be seen that a section of the nozzle valve assembly 1 and its valve closure element 21 is represented as a reminder that this is the structure that is being provided electrical and thermal clearance from the columnar insulator 9 by the shape of the columnar insulator 9.

Drawing FIG 13 is a three-dimensional wire-frame side view of the tapering end of columnar insulator 9 which is exposed to the combustion chamber, as seen from the side of the fuel injector, showing how its conical upper shape like that of a normal spark-plug varies along its axis, becoming indented while tapering and tilting to provide electrical and thermal (combustion gas circulation) clearance from the nozzle valve assembly I on its one side and the chamfered inner wall of the threaded mounting cylinder 2 on its opposite side (cf.Also FIG 1-3, 11).

Drawing FiG 14 is an end, axis centered view of the columnar insulator 9 of FIG 13, the axis being that of the conical upper structure and of the entire spark plug. Note that the same contours as in FIG 11, 12 D, and 13 are shown.

Drawing FIG 15 is a functional schematic diagram meant to be viewed simultanemusly with drawings FIG 16 & 17 of the inventive fuel rail (or functionally equivalent high pressure fuel source 34) based energize to inject type piezoelectric (or other high-speed actuator actuated) fuel (or other fluid medium) injector metering valve system in its not-energized, shut-off state. In contrast to the more basic and simple analogous system of FIG 19 and 20, the system of FIG 15-17 incorporates an optional residual pressure discharge control valve 35 and its supporting elements to eliminate in limited circumstances possible pressure bleed off delay after the piezoelectric element is de-energized to close the nozzle valve assembly I and stop the fuel injection. Arrows show the presence, path, and direction of fuel flow.

Drawing FIG 15 is a geometrically functional working model, with exaggerated axial movement for illustrating relative movement of the parts of the piezoelectric fuel injector metering valve system. The schematic diagram does not show obviously missing but is presumed present details such as valve bias springs and seals between the various chambers having different pressures. The schematic diagram does show optional sleeve bearings 36 supporting the valve and its actuator stems, because this is far simpler to understand than any attempt to symbolize their alternate valve guidance method based on the Stirling engine piston guiding principle, which is in fact shown in FIG 24 explicitly as an example, but also implicitly in drawings FIG 6 & 7 of the nozzle valve assembly I which embodies the same Stirling engine piston guiding principle to align and center the valve closure elements 21.

Applicable both to fuel injectors wherein the metering valve is separate (discrete) from the injector-igniter, as well as to fuel injectors wherein the metering valve is internal (integral) to the injector-igniter, FIG 15-17, 19, 20 illustrate by functionally accurate two-dimensional working model schematics a complete typically fuel rail (high pressure fuel source 34) based fuel injection system of the generally most advantageous,,energise to inject" operational principle, featuring a peizoelectric actuator, focusing on its inventive fuel metering component.

The high speed actuator actuated fluid medium metering valve system of FIG 15 - 17 shows schematically such a system which includes an optional residual pressure discharge control valve 35 and fuel discharge system (anti bleed-delay system) comprising the residual pressure relief valve 17 with its pull-only coupler 37, a fuel boiling prevention pressure regulation system, or anti-boiling pressure regulator 38 which may optionally be included in this optional system, typically comprising a pressure vessel with an outlet pressure regulator to hold a constant or computer controlled variable pressure within said vessel, with a fuel channel to the fuel discharge destination 39, which may be in the case of liquid fuel return to the fuel tank, not shown, or in the case of gaseous fuel, discharge to the engine air intake manifold, not shown, or as the designer may decide.

The purpose of this anti bleed-delay system is to eliminate the long injector bleed-off tail" of the internal pressure curve FIG 18B of the nozzle valve assembly 1 internal pressure, which delays closing of the nozzle valve assembly I in situations where excessive compressive energy is stored between the high pressure inlet control valve 40 seat and the nozzle valve assembly I seat in their simultaneously closed positions, wherein io pressure above the closing pressure of the nozzle valve assembly 1 is prolonged.

One common application which could create the presence of the bleed off,,tail" of FIG 18B, necessitating the use of a residual pressure discharge control valve 35 as in FIG 15, is use of gaseous fuel in its gaseous state prior to fuel injection, due to the gas phase being a compressible medium. Where the use of a residual pressure discharge control is valve 35 is indicated, the relatively small amount (in comparison to the direct.-injected amount) of gaseous fuel discharged by this valve could not easily or simply be returned to its fuel tank, because such a tank would have high pressure, which would suggest the option of routing the relatively small amount of the thus discharged residual fuel to the air intake manifold of the engine (not shown), where probably the combustion characteristics of such a scheme can be managed, resulting in relatively little wasted fuel in comparison with the most efficient non direct injection systems.

The use of both liquified and non-liquified gas is especially suitable to the present invention due to its unique advantage of being able to totally eliminate the use of optional sleeve bearings 36 which quickly gall and wear out in the absence of lubrication. This is noteworthy in relation to the current popularity of Compressed Natural Gas (CNG), Liquified Natural Gas (LNG), and Liquified Petroleum Gas (LPG) or propane as vehicle fuels. This unique ability addresses the lubrication issue: no form of gaseous fuel naturally contains lubricants. The art of addition of lubricants to fuels or to the systems using them is well known. However there is far less need of lubricants in the present invention because reliance on optional sleeve bearings can be entirely eliminated by application of at least two sufficiently widely spaced Belleville springs supporting in common the shaft which would normally require optional sleeve bearing 39 support. This is the well known friction less principle of the Stirling Engine piston. Thus in every instance where optional sleeve bearing 39 is indicated in the present invention, that sleeve bearing can be eliminated by application of at least two sufficiently widely spaced Belleville springs to the shaft otherwise needing optional sleeve bearing 39 support. Because for either the residual pressure discharge control valve 35 or the high pressure inlet control valve 40, Belleville springs 24 for biasing purposes may be mounted on both the inlet and the outlet sides of the valve seat 25, this ability guarantees that alignment and centering support by the Belleville springs 24 alone without aid of optional sleeve bearings 36 can be sufficient, because in most applications use of multiple Belleville springs on one side only of the valve seat 24 is sufficient to insure valve closure element 21 alignment and centering in its valve seat 24 without aid of sleeve bearings.

And in every instance where pressure isolation is required between various chambers of the invention, such pressure isolation can be entirely satisfied by use of io flexible sealing diaphragms, independent of recourse to the partial sealing property of sleeve bearings. Therefore, there is no requirement for the use of any sleeve bearings whatsoever in conjunction with any aspect of the present invention. However, the option of use of sleeve bearings is a valuable convenience in some circumstances, as illustrated in FIG 24 where liquid fuel is expected, and therefore is illustrated in the present invention is as an unessential option.

In regard to leakage seals between valves and couplers along their interconnecting shafts, the shown optional sleeve bearings 36 can perform as smooth bore close fit liquid leakage restrictive seals, where limited leakage may be tolerated, for example by return flow of liquid to the fuel tank as the fuel discharge destination 39. A detailed example valve spring and pressure seal arrangement of the type represented by the present and similar schematics FIG 16, 17, 19,20 is shown in detail in FIG 24.

Whereas use of Belleville springs may eliminate the need for any or all optional sleeve bearings 36 in the present invention, the converse is also true: the use of sleeve bearings may eliminate the need for any or all Belleville springs 24 in the present invention. There is nothing in the control valve system of the present invention which necessitates the use of Belleville springs or sleeve bearings: if sleeve bearings are used, Belleville springs may be eliminated, and if Belleville springs are used, sleeve bearings may be eliminated. Even exchange of the nozzle valve assembly I according to patent application FCTIEP2OIO/061790 in drawings FIG 15, 16, 17, 19, or 20 for one not using BeIleville springs is within the scope of the present invention. If Belleville springs are eliminated, their obvious replacement is the coil spring. Coil springs used in conjunction with or without sleeve bearings are not illustrated in the present invention, but the use of either or both is in accordance with the present invention.

Thus in the diagram of FIG 15 the nature of the biasing springs may be Belleville or spiral, or some other kind, and the means of valve guidance and centering, may be the Stirling engine (Belleville spring) principle, sleeve bearings, or any other means, and the nature and technology of the nozzle valve 1 which is being served is optional, and whether the application being served is an injector-igniter according to the present invention, or a fuel injector in general for any kind of engine is optional.

Drawing FIG 15 (and likewise the related FIG 16, & 17), represents a control valve system suitable for but not limited to use in a fuel injector, comprising a solenoid, piezoelectric (preferred), or similar high-speed actuator actuated fluid medium metering valve system of energize to meter type wherein the high-speed actuator 41 drives a push-only coupler 42 connected to a normally closed high pressure inlet control valve 40, io preferably insuring by a push coupler linkage gap 43 of said push-only coupler 42 that no force is transmitted to said high pressure inlet control valve 40 while said high-speed actuator 41 is not energized despite normal system tolerance changes comprising limited valve seat wear, which normally closed high pressure inlet control valve 40 meters a pressurized fluid medium from a high pressure fuel source 34 which may be a fuel rail into is a fluid channel connected to an inward-opening or outward-opening fluid medium injector nozzle valve assembly 1, wherein (preferably) the direction of fluid medium pressure reinforces the normally closed high pressure inlet control valve 40 closing spring bias on its valve closure element 21, directed from the larger diameter of its valve seat taper towards its smaller diameter, and wherein the fluid connection between the high pressure inlet control valve 40 and the nozzle valve assembly I is also connected to the input of a residual pressure discharge control valve 35 which is likewise (preferably) oriented so that its input pressure likewise assists in holding its valve closure element 21 closed, which opens at nearly the same instant that the high pressure inlet control valve 40 is closed by de-energization retraction of said push-only coupler 42, allowing said residual pressure contained between the fully closed high pressure inlet control valve 40 and the spring assembly 20 biased closed but ejecting nozzle valve assembly I to instantly drop to a level below the nozzle valve assembly I closure pressure to a preferably regulated fluid medium boiling prevention pressure above the fuel vaporization pressure at the injector working temperature in the case of liquid fuel by the optional anti-boiling pressure regulator 44, by opening of the residual pressure discharge control valve 35 by its mechanical linkage to the pull-only coupler 37 connected by a shaft connection axially passing though the high pressure inlet control valve 40 to the push-only coupler 42 at its opposite end, whereby the valve closing bias spring assembly 20 of the high pressure inlet control valve 40 overpowers the weaker valve closing bias spring assembly 20 pressure of the oppositely oriented residual pressure discharge control valve 35, so that while the high pressure inlet control valve 40 (stronger bias) is normally closed, the residual pressure discharge control valve 35 (weaker bias) is pulled and held open against its spring spring assembly 20 by the more powerful spring assembly 20 of the the former, except when the former is overpowered via the push-only coupler 42 by the high-speed actuator 41, forcing the high pressure inlet control valve 40 open, and releasing the residual pressure discharge control valve 35 so that it closes by its own relatively weakest spring assembly 20, preferably insuring by a pull-only coupler 37 pull coupler linkage gap (cf. FIG 16 & 17) that no force is applied to said control valve while said actuator is energized despite normal tolerance changes including limited valve seat wear (cf. FIG 15 -17).

Both of the metering and residual pressure discharge control valves 36 of this system, as well as the spring biasing of the piezoelectric stack, preferably use parallel stacked Belleville springs according to designs disclosed in patent application PCT/EP2OI 0/061790, similar to that of the fuel injector nozzle valve at the bottom of schematics FIG 15-17, 19, 20. A detailed view of an example of an embodiment of the is high-pressure metering valve is shown in drawing FIG 23. This detailed view depicts the metering valve in its not-energized, relaxed shut off state, resulting in no fuel flow to the fuel injector nozzle valve.

Drawing FIG 16, meant to be considered simultanemusly with drawings FIG 15 & 17, shows the same piezoelectric metering valve system schematic as in FIG 15, except that the valve is shown in its energized, open state, causing fuel injection by the fuel injector nozzle valve. The same description as for drawing FIG 15 applies to FIG 16.

Drawing FIG 16 presents the metering valve system in its energized to inject state, as a graphic contrast to Drawing FIG 15 which presents the metering valve system in its not energized, closed injector state. Arrows show the path and direction of fuel flow. In FIG 16 we see the high-speed actuator 41 fully extended, wherein the push-only coupler 42 engages the high pressure inlet control valve 40, forcing it open against its bias spring (not shown), and at the same time moving the pull-only coupler so as to cause it to relax its pull upon the residual pressure discharge control valve 35 being held open against the bias of its closure spring, closing it by action of its bias spring (not shown). Notice how by this action a small pull coupler linkage gap 45 opens up, ensuring that dimensional changes in the system such as valve seat wear or thermal expansion will not affect the full closing of the residual pressure discharge control valve 35. This gap serves an analogous function to that of the push-coupler linkage gap 43 in the discussion of the previous drawing FIG 15.

Drawing FIG 17, meant to be considered simultanemusly with drawings FIG 15 & 16, is a composite, ,,dynamic" view of both FIG 15 and FIG 16, being a two-dimensional dynamic" split view of the opening and closing action of the piezoelectric metering valve, illustrating how the residual pressure discharge control valve works to instantly bleed off any residual fuel pressure in the fuel metering valve sysem at the instant that the high-speed actuator 41 piezoelectric element is de-energized. The left hand side of the split view of the control valve system depicts its energized, injecting state; and the right hand side shows its not energized and not injecting state. Arrows show the path and direction of fuel flow.

By inclusion of the fuel injector nozzle valve assembly 1, each schematic, FIG 15 -io 17, compriseses a complete, self-contained peizoelectric fuel injector, supplied by an inlet regulated high-pressure fuel reservoir, known to the modern art as a,,fuel rail" optionally embodying its high pressure fuel source 34, and in the case of liquid fuel at atmospheric pressure, returning the excess fuel causing bleed-delay to the fuel tank optionally embodying its fuel discharge destination 39, advantageously via a pressure regulated is outlet fuel rail, or other pressure regulating device which maintains a minimum boiling prevention and maximum return flow channel pressure, which through the open residual pressure discharge control valve 35 pressurizes the nozzle valve assembly I internal cavity and connecting fuel channels to prevent or limit fuel boiling (vaporization) in the nozzle valve between injections, in situations where such control valve complexity is justified.

FIG 17 schematically shows graphically the exaggerated dynamic action implied by FIG 15 -16, wherein the dimensions of the dynamically contrasted side by side parts are dimensionally accurate in the sense that they are sufficient for making an illustrative two-dimensional cardboard working model of the entire system wherein movement is neccessarily exaggerated for purpose of illustration.

Drawing FIG 18 A, B, C, and D shows a synchronized set of timing diagrams illustrating the operation of the dynamic metering valve action depicted in FIG 17. It is an idealized schematic timing diagram of the (commonly piezoelectric, and for purpose of discussion so held to be) metering valve systems depicted by FIG 15-17, 19, 20, fed by a high pressure fuel source 34 which would commonly be a fuel rail, wherein diagrams A, B, C, and D all have in common the same horizontal time axis so that their relative actions indicated on their dfferent vertical axes can be compared.

FIG 1 8A vertical scale indicates the idealized working displacement of the working end of the piezoelectric stack in response to an electrical piezoelectric stack or solenoid energization pulse which is not shown, but whose vertical rise and fall edges coincide with the beginning of the rise and fall slopes of FIG 1 8A, wherein the lower horizontal line indicates the fully closed, electrically de-energized position, and the upper horizontal line indicates the fully open, energized position of the piezoelectric (or alternatively solenoid) high-speed actuator 41.

FIG 18 B plots the fuel pressure in the fuel channel between the valve seat of the high pressure inlet control valve 40 and the valve seat of the fuel injector nozzle valve assembly 1 in the case where a residual pressure discharge control valve 35 is not present, such as in FIG 19 & 20, suffering from an extended fuel injection bleed off after the piezoelectric metering valve shuts off, due to conditions such as large fuel volume or io some other condition of the fuel whereby it can store enough energy by compression to create the,,bleed off" tail following de-energization of the high-speed actuator 41.

Examples which do not have a residual pressure discharge control valve 35 because it is not needed are shown in FIG 19 -20. The limitation of such a system becomes noticable only in cases where the volume and nature of the fuel channelled between said valves is is sufficiently compressible to adversely delay the injector's nozzle valve assembly I shutoff timing, causing an extended period of fuel bleed off through the nozzle valve after the piezoelectric actuator is de-energized. Sometimes such bleed-off can be managed or exploited, but in some situations it may degrade engine performace resulting in reduced fuel economy and elevated emissions. But in compact high-performance designs, such as in FIG 19 and 20, there should not be enough volume in said fuel channel to retain compressive energy for unacceptable extended bleed-off of fuel into the combustion chamber. Furthermore, the examples of FIG 19-20 enjoy multiple advantages of simplification over FIG 15-17, including eliminated need for return flow to the fuel tank.

And where the fuel metering system is discrete, as in FIG 1, the engine itself, or the application may be of low technology as to eliminate need for a residual pressure discharge control valve 35, and wherein the fuel metering valve function of providing pressure impulses of fuel may be addressed by a rich variety of means from past art which do not include a piezoelectric metering valve.

FIG 18C shows the improved response curve of fuel pressure between the high pressure inlet valve and the fuel injector nozzle valve benefitting from the action of the residual pressure discharge control valve, stopping the injection as soon as the metering valve shuts off. As applied to a system which without benefit of the residual pressure discharge control valve 35 would produce the undesirable response of FIG 18B. FIG 180 may also represent the system of FIG 19, 20 where compressibility of the fuel between the high pressure inlet control valve 40 and the valve seat of the fuel injector nozzle valve assembly 1 is not large enough to sustain a significant bleed-off" tail as in FIG 18B.

FIG 18D shows the pulses of fuel flow rate at the output of the pressure relief valve which correct the system depicted in FIG 18B to behave as the system of FIG 180.

Drawings FIG 19 -20 schematically show a subset of the system of FIG 15 -17 to which the description of FIG 15 respectively applies, which does not have or need a residual pressure discharge control valve 35 system because the fuel volume involved in the bleed-delay process is too small to accumulate sufficient energy to sustain a prolonged, objectionable nozzle valve assembly 1 bleed-delay process. No fuel return valve and line to the fuel tank or some other fuel discharge destination 39 is neccessary.

Drawing FIG 19 shows the inventive piezoelectric metering valve schematic for io systems where the amount of compressive energy stored in the fuel channel between the valve seat of the high pressure inlet control valve 40 and the valve seat of the fuel injector nozzle valve assembly 1 following de-energization of said metering valve does not cause problematic injection pulse prolongation. In this case a residual pressure discharge control valve is not needed, corresponding to the preferred embodiments of FIG 21 -23.

is The schematic diagram depicts the metering valve in its not energized, relaxed, closed state. As in the schematic diagrams FIG 15 -17, the schematic does not show obviously missing features such as valve bias springs and seals between the various chambers having different pressures. In regard to seals, the shown optional sleeve bearings can and should perform a limited function as a leaking seal, where leakage may be tolerated, for example by return flow to the fuel tank. And as described for FIG 15, sleeve bearings may optionally be entirely avoided in the present system, wherereby their valve guiding and centering function is replaced by the equivalent but frictionless function of the Stirling engine principle inherent in the use of Belleville springs, and where the sealing function between various chambers needing isolation is accomplished by diaphragm seals. A typical valve spring and pressure seal arrangement is shown in detail in FIG 24, applicable wherever needed in the schematics.

The system of FIG 19 shows the high-speed actuator 41 in its not energized, retracted condition wherein the push-only coupler 42 is fully relaxed, exhibiting its open push coupler linkage gap 43, intended to compensate for valve seat wear and temperature and other tolerance variations over time and varying circumstances which could otherwise lead to the presently closed high pressure inlet control valve 40 not closing fully when the high-speed actuator 41 is not energized. In this condition, the path between the high pressure fuel source 34 and the nozzle valve assembly 1 is blocked, preventing fuel injection, which would otherwise occur due to the high pressure of the fuel forcing open the spring biased normally closed nozzle valve assembly 1.

Drawing FIG 20 shows the inventive piezolectric metering valve of FIG 19 in a composite, dynamic split view, showing said metering valve in both open and closed states. The left hand side of the split view of the control valve system depicts its energized, injecting state; and the right hand side shows its not energized and not injecting state. Arrows show the path and direction of fuel flow.

FIG 20 schematically shows graphically the exaggerated dynamic action implied by FIG 19, wherein the dimensions of the dynamically contrasted side by side parts are dimensionally accurate in the sense that they are sufficient for making an illustrative two-dimensional cardboard working model of the entire system wherein movement is neccessarily exaggerated for purpose of illustration.

Drawings FIG 21 and 22 illustrate examples, differing but slightly, of a completely self-contained injector-igniter, incorporating within its body a complete metering valve system, for purposes of illustration only being of the fuel-rail based piezoelectric variety, is but unlimited in principle. FIG 23 is an enlarged view of important details of FIG 21 and 22 not discussed as identical details earlier.

Drawings FIG 21 and 22 differ only in the interchange of position of their two electrical connectors, which needs no explanation. Therefore both configurations will be discussed generally in reference to FIG 21 and FIG 23.

Inconsequential obvious liberties were taken in the two-dimensional cross-section representations cutting through the injector-igniter axis of FIG 21, 22, and 23 in that all of the depicted holes could not have been most conveniently drilled in the cutting plane of the cross-section, wherein any alternative cutting plane through the axis of the fuel injector is available to avoid the apparent drilling conflicts. Similar observations apply to the apparent drilling of curved holes, and neglect to show the internal threads of the high pressure fuel inlet pipe connection fitting 46, schematically replaced by a simple drilled hoie in soiid metal, being an obvious short-cut to spare the effort of drawing obviousiy inconsequential minor details.

Starting from the bottom of FIG 21, we find this embodiment to be basically the embodiment of FIG 1 simply split into relative lower and upper halves, with insertion of a piezoelectric fuel-metering valve between. FIG 21 is of course, as any clean and compact solution, interesting, revealing multiple applications and advantages of miniature Belleville spring stacks in replacing more bulky and complex coil spring based arrangements.

The lower spark plug half is seen as nearly identical to that of FIG 1, excepting trivial exchange of outward-opening for inward-opening nozzle valve assembly 1, eleimination of its swiveling fuel inlet collar 10 (in exchange for much simpler well-known application of indexing washers of calibrated thicknesses (not shown) to accomplish the same purpose), and relocation of its driving hexagonal 8. A slightly larger injector-igniter unit driving hexagona 8 is disposed conveniently at the top of its housing shell 6, suitable for both socket (including torque wrench) and spanner driving. New to said lower spark plug half are the tapering high pressure fuel seal 47 and tapering high voltage leakage seal 48 cable connection by means of tapering compression fittings (a non-limiting choice) io for convenience of reliable assembly. Location of the radio frequency interference resistor has broad possibilities within the electrically shielding preferably metallic housing shell 6 of the injector-igniter, and is therefore not shown. Similarly, the specifics of various cable connections are not detailed, but left unspecified as obviously suggestive simple dividing lines between connecting electrical parts.

is Afew details of FIG 21 benefit by clarification. The piezoelectric stack 49 is in principle mounted according to industry normal practice, having a pivoting ball and socket end mount 50, and a spring biased compression mount 51 at its opposite end, the purpose of which is twofold: to provide compressive bias to the piezoelectric stack 49, and to provide mounting of the stack which avoids any possibility of bending of the stack. The present embodiment apparently differs from the state of the art in that it applies the same type of spring assembly 20 embodied as a Belleville stack means and method to bias and align and center the piezoelectric stack 49 as is disclosed in patent application PCTIEP2OIOIO6I79O to bias, align and center the nozzle valve assembly 1, and as similarly applied in the present invention to bias, align, and center the control valves.

Notice that in the application of the concepts of PCT/EP2OIO/061790 to the control valve application and the piezoelectric stack application in FIG 21, 22, and 23, no optional sleeve bearing 40 is used in either case for guidance of the respective application devices, but in both cases alignment and centering function is entirely performed by the Belleville stack spring assembly 20. This further demonstrates the broader applicability of the principles claimed more narrowly in patent application PCT/EP20101061790, and pursued in the present document.

The side mounting cross-section view of the piezoelectric injection control connector 52 of FIG 21, needs explanation in that the interconnection view between the dielectic (normally plastic) housing of said connector body and the metal housing shell 6 of the injector-igniter intends to show two short concentric cylindrical connecting protrusions which in cross-section are visible only as four stub projections, the two outer projectons showing the larger metallic cylinder cross section, and the two inner projections showing the smaller inner cylinder cross section, wherein the larger of which metallic cylinders grips by a possible bond around the cylindrical periphery of the plastic electrical connector body. The inner concentric cylinder is embedded within the plastic of said connector body, providing a second or alternative bond, if desired.

The arrangement of the fuel inlet pipe connection fitting 46, and of the two electrical connectors illustrate the secure segregation which is needed between flammable fuel connection, safe spark-ignition, and sensitive electronic control signal connectors converging onto a single cylinder. The arrangement of FIG 22 may in some circumstaces have slight advantage over that of FIG 21 in providing more physical separation between the fuel and the spark-ignition connectors. The state of the art has long dealt with similar proximity issues of high voltage and fuel connections, which practice should address any concerns. There is ample possibility of even wider spacing of these connections if neccessary, but th present arrangement offers good compactness, is relatively short overall length, a smooth extended cylindrical trunk usefully distancing the branching fuel and electrical connections from the mounting hole in the cylinder head.

Obviously, instead of threaded mounting, with its multiple advangages of superior fuel injector and spark plug electrode cooling and simplicity, the currently popular clamp-mounting alternative is applicable. Any concerns about lateral engine vibration in the threaded embodiment are easily addressed by lateral strut support, but of doubiful neccessity.

Drawing FIG 23 enlarges details of both FIG 21 and 22.

In the lower part of FIG 23 are two compression sleeves. The narrow one on the left is the fuel inlet pipe connection fitting 46, likely of metal, for the high pressure fuel channel connection between the fuel metering valve in the upper body of the injector-igniter, and the nozzle valve in the lower body of the injector-igniter. And the larger compression sleeve to its right (of silicone rubber, for example) is the tapering high pressure fuel seal 47 sealing and locking the high-voltage electrical connection by means of its compression screw part above it, wherein the compression screw, the high voltage cable insulation, the silicone compression sleeve, and the spark plug dielectric are all of high voltage dielectric materials. The accurately scaled illustrated diameter of the central electrode and of its high voltage connection cable are 2.5mm, which is typical for the central conductor in a 14mm spark plug. 2.5mm high voltage cable using Teflon insulation is commercially available rated for 40KV, which is quite adequate for spark plug applications, and can obviously be increased where needed.

Immediately above the high voltage cable termination is the fuel metering means performed by the high pressure inlet control valve 40, which in its structural arrangement and principle of operation is identical to the outward-opening injector nozzle valve, but is operated and used very differently. Whereas the nozzle valve assembly I is operated by fuel pressure from inside the valve to open the valve against its spring bias, in the metering high pressure inlet control valve 40, the fuel flow is reversed, such that when the valve is closed, fuel pressure cooperates with the valve spring assembly to press the valve closed, relying on the immense force of the piezoelectric stack to open the valve against the combined spring and fuel pressure.

From the fuel inlet connector, fuel enters into a pressure tight inlet chamber of the metering high pressure inlet control valve 40 cylindrical housing, and upon energization of the piezoelectric stack 49 flows through the opened metering high pressure inlet control valve 40 from against the opening direction of the metering high pressure inlet control valve 40 into the interior chamber of the metering high pressure inlet control valve 40, is flowing though the hollow interior of the valve closure element 21 through the hollow interior of its valve stem stem-shaped part 22 which passes through the Belleville spring stack spring assembly 20, and out through the end of the hollow valve stem stem-shaped part 22 into a shallow cavity in the end of the cylindrical piezoelectric actuator cylindrical valve lifter element 53. From the hollow end of the valve lifter element 53, the fuel from the valve stem flows radially outward through apertures (in this case radially drilled holes) at the end of the valve lifter element 53 into the space above the Belleville spring stack spring assembly 20, leaving the interior chamber of the metering high pressure inlet control valve 40 by its fuel exit hole, which after a right angle passes through the tapering high pressure fuel seal 47 into the fuel channel of the preferably threaded mounting cylinder 2 of the injector-igniter leading to the nozzle valve assembly 1, which opens in response to its open direct fluid communication with the fuel rail pressure, injecting fuel into the combustion chamber for as long as the fuel metering high pressure inlet control valve 40 is held open by energization of the piezoelectric stack 49. Instantly as the piezoelectric stack 49 is de-energized, due to the nearly perfect incopressibility of the fuel, and the very limited volume between the nozzle valve assembly I and the fuel metering high pressure inlet control valve 40, the pressure drops within the nozzle valve assembly I and the interior chamber of the fuel metering high pressure inlet control valve 40 to the opening threshold pressure of the nozzle valve assembly I, closing the nozzle valve assembly I. In addition, it may be advantageous, as illustrated in FIG 23, to use a metering high pressure inlet control valve 40 having a valve seat 25 diameter considerably larger than that of the nozzle valve assembly 1, primarily due to the fact that the stroke of a normal piezoelectric actuator is 0.1% to 0.2% of the length of the piezoelectric stack 49.

The piezoelectric stack 49 of the example as drawn in FIG 21 and 22 proportioned to the 14mm spark plug thread standard is about 50mm in length giving a stroke range from s 0.1% to 0.2% of piezoelectric stack 49 length of 0.050mm to 0.100mm. The working stroke of the nozzle valve assembly I is about 30* m (microns), or 0.030mm. Therefore, the opening stroke of the fuel metering high pressure inlet control valve 40 is nearly twice to over three times the opening stroke of the nozzle valve which it controls, which suggests that a metering high pressure inlet control valve 40 diameter of at least equal to io that of the nozzle nozzle valve assembly I may be enough to provide adequate flow.

However, for purpose of illustration, and to remove all doubt, the seat diameter of the metering high pressure inlet control valve 40 as drawn is three times the valve seat 4 diameter of the nozzle valve assembly 1. The actual full scale valve seat 4 diameter of the nozzle valve assembly 1 is 1.44mm, and the valve seat 4 diameter of the metering is high pressure inlet control valve 40 is 4.31mm, for a 14mm standard spark plug size.

Therefore the relative apertures of the nozzle valve to the metering valve are the ratio of (Dn x Hn)I(Dm x Hm) where D is the valve diameter, H is its lift height, n designates the nozzle valve, and m designates the metering valve: (Dn x Hn)I(Dm x Hm) = (1.44mm x 0.O3Omm)t(4.31 mm x 0.050mm) = 1:4.988 or 1:5 using the more conservative 0.050mm piezoelectric lift.

A minimum five fold metering valve opening aperture advantage over its nozzle valve opening aperture should eliminate any concern over adequacy of the metring valve to provide the necessary fuel flow. That means that the piezoelectric stack 49 may in theory be much shorter than it is depicted. That it could be shorter by half, using the same metering high pressure inlet control valve 40 would seem reasonable.

The moving, or actuator rod end of the piezoelectric stack 49 is biased, supported, aligned, and centered in a frictionless manner by the inventive Belleville spring stack of spring assembly 20 according to the present invention and of patent application FCTIEF2O1OIO6179O. The large diameter end of the Belleville spring stack spring assembly 20 rests by a close radial fit to the cylindrical cavity wall aganst the end of the cylindrical piezoelectric stack 49 housing cavity, and its small diameter end presses against the annular shoulder of the cylindrical base of the piezoelectric stack actluator rod 54 which is held in a radially fixed relationship to the piezoelectric stack (by bonding or other means), thus biasing, supporting, aligning, and centering said piezoelectric stack 49.

Said Belleville spring stack spring assembly 20 has a close contact fit within the cylindrical cavity housing the piezoelectric stack 49, and the piezoelectric stack actuator rod 54 is held by a close contact fit by the center hole of the Belleville stack in such a way that negligible bending force is applied to the piezoelectric stack. Perfect allignment of the piezoelectric stack axis with the metering high pressure inlet control valve 40 axis is unneccessary due to the radial independence of these two axes by means of valve lifter element 53, whose radial independence from the piezoelectric stack actuating rod 54 makes possible to maintain a radially free (non-binding) smooth bore close tolerance pressure restrictive fit of the valve lifter within its optional sleeve bearing 40 bore mechanically connecting through the end of the metering valve cylindrical cavity housing, io which optional sleeve bearing 40 surface benefits by the lubricating presence of the ambient fuel.

Furthermore, a fluid and gas-tight seal is provided between the metering high pressure inlet control valve 40 cavity and the piezoelectric stack 49 housing cavity by means of a flexible diaphragm 55 membrane element, preferably metallic, disposed at the is end of the piezoelectric stack actuator rod 54, having a gas-tight seal at the end of said rod 54, and having a second gas tight seal at the exit surface from the piezoelectric stack 49 housing cavity from which said rod 54 emerges. The flexible diaphragm 55 must resist the great fuel rail pressure, and the vibrations of the metering high pressure inlet control valve 40 activity, although the relative stroke of the piezoelectric stack 49 is negligible in relationship with the dimensions of the bellows. This small stroke enables use of relatively thick walled and stiff metallic flexible diaphragm 55 neccessary to withstand the great pressure.

Unique to this fuel injector arrangement is its compactness and simplicity due to the inventive use of Belleville springs according to patent application PCT/EP2OIO/061790, avoiding complicating control mechanisms common to all other piezoelectric fuel injectors, which is the basis for its performace and economical advangages. This affords technichal advantage of ease and flexibility of arrangement of its parts, because the compact integrated structure is open and uncluttered, wherein the functional units are separated so as to avoid functional compromise.

Drawing FIG 24 shows a stretched, standoff version of the swiveling fuel inlet collar arrangement of FIG 1 and FIG 8, to provide better access, which is self-explanatory.

Other than the obviously stretched mid section of this example, it is identical to and fully explained by the descriptions pertaining to FIG 1, including the descriptions for FIG 2, 3, 6,7, & 8.

Drawing FIG 25 dynamically demonstrates a Belleville spring corrugation shape designed to minimize spring internal stress under compression, which is a measure of the spring's resiliency, while maximizing spring force, the optimization of this combination being a measure of the spring's efficiency. Drawing FIG 25 shows computer calculated and generated shapes of a specific corrugated Belleville spring, respectively the relaxed shape and its shape when compressed to its designed working force, wherein the shape and all aspects of the corrugation are designed to minimize spring internal stress (a vital characteristic of the spring resiliency, which is more than merely the slope of the spring's force versus displacement curve) at the required working force, which must by all means be below the metal yield point, or point of permanent deformation, for a selected io convenient and practical spring thickness in view of manufacturing, which in the present case of a 5mm diameter annularly corrugated Belleville spring, is chosen to be 0.100mm.

Studies by the inventor have demonstrated that the choice of one or two wave peaks of annular corrugation of relatively low amplitude, as seen in FIG 25, provides the greatest force in combination with the greatest resiliency, which is ideal for a Belleville is spring intended for dynamic short-stroke applications such as fuel injectors, in not only the nozzle valve, but in the control valves and for biasing, supporting, aligning and centering the piezoelectric stack as well, all in practically one and the same manner.

Corrugation is neccessary in order to modify the Belleville spring 24 characteristic curve to comply with a required working force and stroke of the Belleville spring 24, achieving by the most compact means the greatest spring force in combination with the greatest resilience of the Belleville spring 24, where resilience" is for purposes of the present invention primarily the ability or quality of the spring material to resist permanent deformation for any given force, rather than,,elasticity', which although a synonym of resilience", might perhaps be associated with the slope of its spring force versus spring displacement curve, not intended here. A quantitative indicator of resilience by this unconventional definition may be remaining relative, or "normalized" force or displacement between a given compression point of the spring, and the point where the metal of the spring begis to yield, or deform, which normalized quantity is expressed as a percentage of the force or displacement from the zero point to the yield (deformation) point. Thus by our ad hoc definition of resilience, a spring reaches negative resilience when stressed beyond the point of permanent deformation at zero resilience. This quality to resist permanent deformation is maximized for any given target force by the inventive one or two wave peak corrugation, which results in the two flattened annular support areas forming under compression.

In a preferred embodiment of the invention the Belleville spring 24 wave-shaped corrugation comprises at least one peak 56, which is oriented from the outer surface of the relaxed Belleville spring 24 towards the inner surface of the Belleville spring 24 (formally, a truncated cone which may support corrugation or any other deformation).

In another preferred embodiment of the invention the Belleville spring 24 wave-shaped corrugation comprises at least one peak 56, which is oriented from the inner surface of the relaxed Belleville spring 24 towards the outer surface of the Belleville spring 24.

And a wave peak 56 is demonstrated in FIG 25 as a point of maximum departure of the corrugated Belleville spring surface from an idealized truncated conical surface io (normal to the truncated cone surface) defined by the inner (central) and outer (peripheral) circular boundaries of one or its opposite corrugated Belleville spring surface.

Preferably the transition from the wave-shaped corrugation (ie wave profile) of Belleville spring 24 to its outer support area 28 of the Belleville spring and/or its central support area 29 occurs at a point in the wave profile where in the (cf. claim 2) biased state is of the Belleville spring 24 the tangent to the wave profile is normal to the central axis of the Belleville spring 24. This condition determines that in its biased state, a Belleville spring exhibiting a one or a two peak 56 wave corrugation in its relaxed state (the peaks 28 being determined by maximum perpendicular distance from the imaginary or virtual conical surface established between the Belleville spring peripheral circle and inner hole circle), shall be supported at its two extremities by annular flat parallel regions of the Belleville spring, the outer support area 28, and the central support area 29. In othr words, the two supporting ends of the conical corrugated Belleville spring 24 will both deform to assume flat annular supporting shapes. It is recognized that said flatness is an ideal condition which may easily be circumvented, but not without challenge from the present patent.

Phyisical contact between parallel stacked Belleville springs is between their annular inner and outer ring surfaces flattened as described by force of compression from a non-flat relaxed condition, normally by mediation of integral or discrete (ie. washer) spacer elements. Care needs to be taken that this stack, when biased will provide maximum force with minimum internal stress in the individual springs, and in particular avoiding the yield point, or permanent deformation stress point in the springs. To achieve this optimum spring performace, the Belleville spring for a given stack should be designed to provide its working bias force according to the following conditions, wherein the Belleville spring flattens from its initial inner and outer boundary circles of contact with its two compressing planes inwardly -flattening from its two outer edges radially inwardly, wherein the two circular boundaries of advancing or expanding annular flatness approach one another radially, as follows: In the design of the fully biased (compressed) spring, the force of support contact at the inner and outer circular edge of the Belleville spring is opposite in direction, and should be at a maximum value for its respective annular region of flatness. In other words, the force of contact of the spring with its adjacent surface decreases monotonically in the radial direction of the opposite annular region of flatness. This maximum force will be at the inner edge of the central support area 29, and at the outer or peripheral edge of the outer support area 28. As a function of increasing radius, this force should by design of the spring decrease to zero for the central support area 29 when the radius reaches the io outer radius of the central support area 29, which is also the outer radius of the central forcing surface 32 and of the central spacer element 27, which press against the central end the spring. Likewise but in the opposite radial direction, as a function of decreasing radius, this force should by design of the spring decrease to zero for the outer support area 28 when the radius reaches the inner radius of the outer forcing surface 31, and/or is the inner radius of the outer spacer element 26, which press against the peripheral (outer or larger diameter) end of the spring.

Unless these one or two peak corrugated Belleville spring design criteria are observed, either more internal stress than is neccessary will exist within the spring, decreasing its resiliency in the sense of operating the spring closer to its yield, or permanent deformation point when compressed between two parallel plane surfaces, which are allowed to be conical supporting surfaces departing within ±300 from the ideal parallel planes, or the pressure will be insufficient to simultaneously fully flatten both the outer and central support areas 28 and 29 of its Belleville spring 24, causing the springs of the stack to be supported more by edge and less by annular surface contact, or by insufficiently flattened annular contact at one or both ends of the Belleville spring, corrupting the spring function (cf. claim 2; FIG 25) and normal stacking. Excessive flattening must likewise be avoided. This is all accomplished by recursive finite element analysis calculations which automatically and recursively find the correct annular corrugation shapes angles, and amplitudes, and wherein the inner and outer extremities which are to be flattened have thus far been straight and not corrugated conical surfaces.

The one, or as thus far has turned out ideally two, wave peaks for the corrugations are the basic constraints of such recursive calculations.

A beneficial but not essential feature of the corrugation which is implemented but scarcely visible due to the slight curvature of corrugation in the realistic computer generated, finite-element analysis calculated relaxed and compressed corrugated spring shapes of FIG 25, is that the outer support area (0.25mm in radial width) and the central support area (0.20mm in radial width) exhibit no corrugation curvature, being simple annular conical surface regions of the relaxed, otherwise curving corrugated Belleville spring. In other words, the required and specified one or two peak corrugation is not restricted to surfaces of radially continuously curving curvature (non-constant first derivative with respect to radius), but may include annular regions which exhibit no curvature (derivative with respect to radius which is constant across the given annular region), so long as the sole condition of one or two wave peaks is met.

Normally, all compressive springs are compressed between parallel flat surfaces.

However, this normal condition is not essential for acceptable performace, even though it io is the ideal and overall best choice. Therefore this ideal condition of the two extremities of the Belleville spring assuming flat and parallel relationship is not intended to be limiting for the present invention, and so the present invention reasonably extends the possibilities of varying the angle of the outer support area 28 or the central support area 29 of the corrugated Belleville spring by ±30°. with respect to the perpendicular to the axis of the is Belleville spring 24 (cf claim 2).

Drawing FIG 25C depicts in its compressed state (compare with its relaxed state in FIG 25B) a realistic and practical inventive Belleville spring 24 having a wave-shaped corrugation consisting of two oppositely oriented wave peaks 56, whose wave-shaped corrugation is annular and symmetrical about the Belleville spring 24 central axis (at radius location 0.00mm). Note that all of the example drawings of the present invention omit explcitly showing a corrugation for reasons of ease of drawing, and that the corrugation is so slight as to be difficult to notice. In all shown applications the Belleville springs are compressed, which tends to flatten the corrugation profile, which moreover is defined and meaningfully measured only for the relaxed configuration of the spring. Also, the use of uncorrugated Belleville springs is within the scope of the present invention, though forfeiting advantages.

Drawing FIG 25 shows computer calculated and generated Belleville spring corrugation shapes specially designed to minimize spring internal stress (a vital characteristic of the spring resiliency), which must by all means be below the metal yield point, or point of permanent deformation, for a selected convenient and practical spring thickness in view of manufacturing, which in the present case of a 5mm diameter spring, is 0.100mm. The particular corrugation also provides a nearly linear spring characteristic slope in advance of the first Belleville spring characteristic peak (Belleville spring characteristics have two peaks, the first a positive or maximum peak, and the second a negative or minimum peak). Avoidance of the destructive yield point is often best accomplished by biasing the spring within the initial rising slope in advance of the initial peak of the classic, well-known S-shaped Belleville spring characteristic curve. The significance of the method of calculation and the shape of the corrugation as illustrated is that the initial rise of the spring characteristic curve to the first peak is very nearly linear for a radially unclamped spring (zero radial force at its outer edge at its bias point). This is an unexpected beneficial result of the two-peak, low amplitude corrugation, since linearization of the slope of the spring characteristic curve is desirable for tolerance to manufacturing variations and factory adjustment of the spring bias point.

Note that the radii of the circular Belleville spring unclamped inner and outer edges expand and contract with changing compressive force on the ends of the spring. If the io inner or outer circular edges of the Belleville spring were clamped, a radial stress would be established at this edge, and the linearity of the slope of the S-shaped characteristic curve would be lost. The spring assembly 20 of interleaved springs and their spacing central and outer washers requires that the spring assembly make contact with its inner adjacent cylindrical surface, which is the surface of the stem-shaped part 22 of the valve is closure element 21. And also the spring assembly 20 must make contact with its outer or peripheral adjacent cylindrical surface, which is the bore of its housing cavity. These two surfaces of contact, central and outer, are essential conditions for the precision guidance of the valve into its valve seat by the spring assembly of Belleville springs accordin to the guidance principle of the Stirling engine piston. Another essential condition for the stacking of this spring assembly is that the Belleville springs must contact either the central cylinder, or the outer cylinder, or both of these cylinders in order to provide the neccessary alignment and centering. The third of these variants does not, of course, permit any radial position adjustment, and depends for its accuracy on the accuracy of the machining of the parts. The other two variants are respectively exhibited in the spring assemblies of FIG 6 and FIG 7. In general, either the central or the outer cylinder is in contact with the Belleville springs, but not both, giving rise to a clutch effect analogous to that in a common automotive clutch disc, which is similarly centered. But the objective in the present invention, as originally established in the original PCT application PCT/EP2O1 0/061790, is to make possible radial adjustments of position of the valve closure element which is rigidly captured either by the central washers of the spring assembly, or by the central holes of the Belleville spring stack of that assembly, or by both, permitting radial adjustment of the axis of the captured valve closure element by the radial freedom of movement by the gap between the outer cylinder wall and the Belleville spring stack periphery, or the gap between the central cylinder wall and the Belleville spring stack central hole, wherein the adjusted radial position at the location of the gap is supported by the clutch action of the interleaved spacer washers and Belleville springs, wherein the washers are in contact with the respective central or outer cylindrical wall, establishing the base of radial suport which is transmitted through the clutch action to the Belleville spring, and finally to the radially opposite set of washers which are in contact with their respective central or outer cylindrical wall. By this interleaved clutch system, alignment and centering of the valve closure element 21 is precisely adjusted and maintained by clutch action within its valve seat 25. Care must also be directed to insure that the annular regions of flatness of the Belleville springs shall overlap their interleaved central and peripheral flat washers with additional annular flatness to spare in the Belleville spring flat annular regions to allow for the anticipated amount of radial relative io movement or sliding with respect to the washers in any radial direction without running into the beginning of the corrugation. The two basic variants of this clutch system are exhibited respectively in the spring assemblies of FIG 6 and FIG 7 as claimed and protected in application PCT/EP2OI 0/061790.

The spring of FIG 25 was designed by finite-element computational methods is incorporating the principles of the preceding paragraphs, producing a remarkable physical compactness (miniaturization) without diminishing spring perform ace, especially beneficial for application to miniaturized and simplified fuel injector control and nozzle valves and for the piezoelectric stack.

All examples of the present invention have complete freedom to adapt (exchange) any Belleville spring 24 corrugation variant, regardless of corrugation wave peak 56 number, wave peak 56 direction, or whether the Belleville spring corrugation is present or not.

Claims (28)

1. CLAIMS1. An injector-igniter apparatus comprising spark ignition device structurally integrated with a direct-Injection (Dl) fuel injector into a common structure for use in an internal combustion engine, the apparatus comprising a high voltage current path which conducts a high voltage to a spark gap (4) between dielectric insulated electrodes (3) and (5) of opposite polarity; wherein the Dl fuel injector comprises a nozzle valve assembly (1), in turn comprising a spring assembly (20);a valve seat (25); and a valve closure element (21) pressed by the biased spring assembly (20) against the valve seat (25); and wherein the direct injector comprises at least one fluid medium channel (16) between the fluid medium pressure source (34) and valve seat (25); the apparatus being characterized by at least one of: both the spring assembly (20) and the valve closure element (21), by virtue of their compactness, being disposed entirely beyond a gas flow point (18) on the surface of the dielectric columnar insulator(9) of a center electrode (3) of said spark-ignition device, in the in the direction of the combustion chamber along the injector-igniter insertion vector of penetration into the internal combustion engine, the gas flow point (18), when the apparatus is installed in an engine, being in freely replenishing gas communication with the combustion chamber; the nozzle valve assembly (1) function being spatially segregated from the spark-ignition function to satisfy their conflicting requirements; and the nozzle valve assembly (1) function being localized for effective fuel injection positioning together with permitting effective spark gap (4) positioning.
2. 2. The apparatus, according to Claim 1, wherein the spring assembly (20) comprises at least one Belleville spring (24), characterized by at least one of: the at least one BelIeviIle spring (24) having an annular and wave shaped corrugation symmetric about the Belleville spring axis; the Belleville spring (24) annular wave-shaped corrugation comprising either one or two wave peaks (56); and the transition of the annular wave-shaped corrugation of the Belleville spring to its outer support area (28) and/or the Belleville spring (24) central support area (29) being located at a point of the wave profile where the tangent to the wave shape of the Belleville spring (24) in its biased state is perpendicular to the Belleville spring (24) axis within ±3Q°.
3. 3. The apparatus, according to claim I or 2, wherein: the inward or outward-opening fuel injector nozzle valve assembly (1) housing is rigidly joined to and at any depth or angle embedded into the tip portion of a preferably io threaded mounting cylinder (2) of the body of the apparatus, the mounting cylinder (2), when the apparatus is installed into an engine, penetrating by its end surface into the combustion chamber of an internal combustion engine either by means of screw threads on its surface, or by other mounting means; a columnar dielectric insulated (9) center electrode (3) of one polarity is disposed is within the preferably threaded mounting cylinder (2), whose spark gap (4) tip emerges from the combustion chamber end of said preferably threaded mounting cylinder (2); the spark gap (4) tip is dielectrically insulated from an opposite polarity high voltage current path supported by said preferably threaded mounting cylinder (2) of the injector-igniter, along with at least one side electrode (5) rigidly supported by the end of said cylinder and served by said current path; and the spark gap (4) is disposed between the said center electrode (3) and side electrode (5), of opposite polarities.
4. 4. The apparatus, according to claim 3, wherein: the nozzle valve assembly (1) is disposed substantially to one side of a plane comprising the central axis of the preferably threaded mounting cylinder (2); an axial view of said nozzle valve assembly (I) presents an eye-shaped profile with the outline of its Belleville spring (24) cylindrical cavity as its "iris"; the outer curve of said eye-shaped profile either nearly coincides with the circle of the combustion chamber penetrating hole of the preferably threaded mounting cylinder (2) or that of its threads; and the middle part of said eye-shaped surface cross-section profile near the apparatus' central axis borders the cylindrical spring cavity iris', establishing a spring cavity wall, after which said wall proceeds to each corner of the eye'; and the eye-shaped geometry benefits cooling and structural contact of nozzle valve assembly (1) with the preferably threaded mounting cylinder (2) and engine cooling system, pyrolytic cleaning exposure of the columnar insulator to the combustion chamber io as needed, and spark gap exposure for fuel ignition.
5. 5. The apparatus, according to claim 3 of 4, wherein: the nozzle valve assembly's (1) spring assembly (20) and valve closure element (21) have a common vector oriented extent from its one end to its other end in the in the direction of the combustion chamber along the injector-igniter insertion vector of is penetration into the internal combustion engine; which common vector oriented extent falls into said vector oriented lateralism with the part of the surface of the dielectric columnar insulator (9) which is exposed to combustion chamber gas circulation when the apparatus is installed in an engine, and/or a distance beyond the end of the dielectric columnar insulator (9) toward the combustion chamber along said vector, beneficially limiting the position of nozzle valve assembly (1).
6. 6. The apparatus, according to claim 5, wherein; an axial extent of the center electrode (2) geometry within said region of lateralism includes a departure of its local axis from the principal axis of the center electrode (3), tilting to avoid the adjacent nozzle valve assembly (1) and toward the opposite adjacent inner wall of the spark-plug preferably threaded mounting cylinder (2).
7. 7. The apparatus, according to Claim 6, wherein the opposite adjacent inner wall of the spark-plug preferably threaded mounting cylinder (2) comprises a local chamfer.
8. 8. The apparatus according to any one of claims 5 -7, wherein axial positioning of the of the fuel injecting end of the nozzle valve behind the spark gap (4) is adapted to enable the angular orientation of a local trajectory of part of its ejected vapour plume(s) into proximity of the spark gap (4) sufficient to achieve its ignition when the apparatus is installed in an engine.
9. 9. The apparatus according to any one of claims 5 -8, wherein: the axially oriented lateral disposition of the nozzle valve spring assembly (20) and valve closure element (21) relative to the dielectrically insulated center electrode (3) while maintaining high-voltage dielectric breakdown clearance from adjacent surfaces includes the insulated center electrode conductor and dielectric structure filling the crescent-shaped space available to it, where the region of lateralism of the center electrode (3) assumes a cross-section profile curvature which is more convex on its side facing away io from the nozzle valve assembly (1) than on its side facing the nozzle valve assembly (1), and which may become concave and curving around the nozzle valve assembly (1); and both extremities of this region of lateralism of the described center electrode (3) cross-section profile transition to their adjacent center electrode (3) trunk and tip circular profiles by generally gradual and uniform transition, thereby establishing center electrode cooling is and structural strength to the extent needed to establish a spectrum of spark-plug operational heat ranges.
10. 10. The apparatus according to any one of the preceding claims, wherein the nozzle valve assembly (1) housing is made substantially of dielectric material.
11. 11. The apparatus, according to any one of the preceding claims, wherein the nozzle valve assembly (1) housing comprises a thermal insulating barrier (33).
12. 12. The apparatus, according to any of the preceding claims, for use with a fluid medium control valve (35, 40), the control valve being characterized by at least one of: the control valve (35, 40) valve closure element (21) being biased by, and being solely or in concert with supplementary sleeve bearing(s) (36), supported, or aligned, or centered in its valve seat (25) by, a spring assembly (20) of parallel stacked Belleville springs (24); the control valve (35, 40) being structured according to outward-opening fuel injector nozzle valve assembly (1), comprising a valve closure element (21) comprising an integral valve stem shaped part (22) which passes through and is guided directly or indirectly by aid of said Belleville spring stack spring assembly (20); employing the direction of the controlled fluid medium pressure which reinforces the valve closing spring assembly (20) bias, being directed from the larger diameter of the valve seat (25) taper towards its smaller diameter; and having a valve stem shaped part (22) which assumes by axial extension from either end of the control valve (35, 40) push rod and/or pull rod control functions.
13. 13. The apparatus, according to claim 12, characterized in that the fluid medium control valve (35, 40) employs the bearing system of the Belleville spring stack spring assembly (20) biased valve closure element (21) which is friction less and uses no sleeve bearing (36); and the mechanical valve coupling of the control valve by which said valve closure element (21) is mechanically coupled to the outside of the cavity enclosing said valve closure element (21) is a smooth cylindrical valve lifter element (53) in a close-fitting smooth bore restrictive to fluid medium leakage from said cavity, leakage being entirely sealable by a pressure tight flexible diaphragm (55).
14. 14. The apparatus, according to any one of the preceding claims, comprising a fluid medium control valve according to claim 12 or 13 in fluid medium communication with its nozzle valve assembly (1), the control valve being either structurally integral to, or structurally discrete from the main body of the injector-igniter.
15. 15. The apparatus, according to any of the preceding Claims, comprising a high speed actuator actuated fluid medium metering valve system of an energize to meter type, characterized by at least one of: the high-speed actuator (41) driving a push-only coupler (42) connected to a normally closed high pressure inlet control valve (40), operable to insure by a push coupler linkage gap (43) of said push-only coupler (42) that no force is transmitted to the high pressure inlet control valve (40) while said high-speed actuator (41) is not energized despite normal system tolerance changes comprising limited valve seat wear; the normally closed high pressure inlet control valve (40) being operable to meter a pressurized fluid medium from a high pressure source into a fluid medium channel (16) connected to an inward-opening or outward-opening fluid medium injector nozzle valve assembly (1); the direction of fluid medium pressure being operable to reinforce the normally closed high pressure inlet control valve (40) closing spring bias on its valve closure element (21), directed from the larger diameter of its valve seat taper towards its smaller diameter; the fluid connection between the high pressure inlet control valve (40) and the nozzle valve assembly (1) also being connected to the input of a residual pressure discharge control valve (35); the residual pressure discharge control valve (35) being oriented so that its input pressure likewise assists in holding its valve closure element (21) closed, which is io operable to open at nearly the same instant that the high pressure inlet control valve (40) is closed by de-energization retraction of said push-only coupler (42); the de-energization retraction of said push-only coupler (42) allowing the residual pressure contained between the fully closed high pressure inlet control valve (40) and the spring assembly (20) biased closed but ejecting nozzle valve assembly (1) to instantly is drop to a level below the nozzle valve assembly (1) closure pressure to a preferably regulated fluid medium boiling prevention pressure above the fuel vaporization pressure at the injector working temperature in the case of liquid fuel by the optional anti-boiling pressure regulator (44); the residual pressure drop being effected by opening of the residual pressure discharge control valve (35) by its mechanical linkage to the pull-only coupler (37) connected by a shaft connection axially passing though the high pressure inlet control valve (40) to the push-only coupler (42) at its opposite end; the shaft connection axially passing though the high pressure inlet control valve (40) to the push-only coupler (42) causing the valve closing bias spring assembly (20) of the high pressure inlet control valve (40) to overpower the weaker valve closing bias spring assembly (20) pressure of the oppositely oriented residual pressure discharge control valve (35), so that while the high pressure inlet control valve (40) (stronger bias) is normally closed, the residual pressure discharge control valve (35) (weaker bias) is pulled and held open against its spring assembly (20) by the more powerful spring assembly (20) of the former, except when the former is overpowered via the push-only coupler (42) by the high-speed actuator (41), forcing the high pressure inlet control valve (40) open, and releasing the residual pressure discharge control valve (35) so that it closes by its own relatively weakest spring assembly (20), preferably insuring by a pull-only coupler (37) pull coupler linkage gap (45) that no force is applied to said control valve while said actuator (41) is energized despite normal tolerance changes including limited valve seat (25) wear.
16. 16. The apparatus, according to any of the preceding claims, comprising a high-speed actuator (41), the high-speed actuator being operable to actuate a fluid medium metering valve system of energize to meter type according to claim 15, comprising a control valve (35, 40) according to claim 12 or 13, the high speed actuator comprising at least one of a solenoid, piezoelectric, or similar high-speed actuator.
17. 17. The apparatus according to any one of the preceding claims comprising a solenoid, piezoelectric, or similar high-speed actuator (41) actuated metering valve system io of energize to inject type according to claim 15 or 16 in fluid medium communication with its nozzle valve assembly (1), said metering valve system being either structurally integral to, or structurally discrete from the corpus of the injector-igniter.
18. 18. The apparatus, according to any one of the preceding claims, comprising a rotationally adjustable (swiveling) fuel inlet collar (7) axially extended to perform a stand-is off function to elevate both the fuel inlet pipe (10) as well as the high-voltage spark plug cable connector above the gasket surface of the mounting hole of said injector-igniter to facilitate connection and service access to the combined injector-igniter unit.
19. 19. The apparatus according to claim 18 wherein the fuel inlet collar (7) sealing washer (13) (gasket) on the collar inner gasket seat (11) is operable to perform a fuel filtering function in its multiple function as the fuel channel and high pressure gasket between the fuel inlet collar (7) collar annular groove (12) and inlet annular groove (14) in the spark plug seat (15) of housing shell (6) of the injector-igniter, such that the collar annular groove (12) functions as a sediment trap under the sealing washer (13) multi-function gasket/filter.
20. 20. The apparatus, according to any of the preceding claims, comprising a means for promoting flash boiling of the injected fuel spray after it is sprayed into the combustion chamber, while maintaining its liquid state within the nozzle valve outside of the injection phase of its injection cycle characterized by any one of: a controlled source of heating in concert with a heating control means to limit the flash boiling temperature of the fluid medium within the nozzle valve prior to injection to above a minimum foreseeable flash-boiling working temperature as required for its flash boiling after it is injected into the combustion chamber, and preferably also to below a maximum allowable temperature; a pressure control means to maintain the fluid medium within the nozzle valve above the vapor pressure of the fluid medium during the part of the injection cycle when the fluid medium is not being injected.
21. 21. A Belleville spring (24), characterized by at least one of: the at least one Belleville spring (24) having an annular and wave shaped corrugation symmetric about the Belleville spring axis; the Belleville spring (24) annular wave-shaped corrugation comprising either one or io two wave peaks (56); and the transition of the annular wave-shaped corrugation of the Belleville spring to its outer support area (28) and/or the Belleville spring (24) central support area (29) being located at a point of the wave profile where the tangent to the wave shape of the Belleville spring (24) in its biased state is perpendicular to the Belleville spring (24) axis within ±30°.
22. 22. A fluid medium control valve (35, 40), the control valve being characterized by at least one of: the control valve (35, 40) valve closure element (21) being biased by, and being solely or in concert with supplementary sleeve bearing(s) (36), supported, or aligned, or centered in its valve seat (25) by, a spring assembly (20) of parallel stacked Belleville springs (24); the control valve (35, 40) being structured according to outward-opening fuel injector nozzle valve assembly (1), comprising a valve closure element (21) comprising an integral valve stem shaped part (22) which passes through and is guided directly or indirectly by aid of said Belleville spring stack spring assembly (20); employing the direction of the controlled fluid medium pressure which reinforces the valve closing spring assembly (20) bias, being directed from the larger diameter of the valve seat (25) taper towards its smaller diameter; and having a valve stem shaped part (22) which assumes by axial extension from either end of the control valve (35, 40) push rod and/or pull rod control functions.
23. 23. The control valve, according to claim 22, characterized in that: the control valve, bearing system of the Belleville spring stack spring assembly (20) biased valve closure element (21) is friction less and uses no sleeve bearing (39); and the mechanical valve coupling of the control valve by which said valve closure element (21) is mechanically coupled to the outside of the cavity enclosing said valve closure element (21) is a smooth cylindrical valve lifter element (53) in a close-fitting smooth bore restrictive to fluid medium leakage from said cavity, leakage being entirely sealable by a pressure tight flexible diaphragm (55) on the outside of the cavity.
24. 24. A high speed actuator actuated fluid medium metering valve system of an energize io to meter type, characterized by at least one of: the high-speed actuator (41) driving a push-only coupler (42) connected to a normally closed high pressure inlet control valve (40), operable to insure by a push coupler linkage gap (43) of said push-only coupler (42) that no force is transmitted to the high pressure inlet control valve (40) while said high-speed actuator (41) is not energized is despite normal system tolerance changes comprising limited valve seat wear; the normally closed high pressure inlet control valve (40) being operable to meter a pressurized fluid medium from a high pressure source into a fluid medium channel (16) connected to an inward-opening or outward-opening fluid medium injector nozzle valve assembly (1); the direction of fluid medium pressure being operable to reinforce the normally closed high pressure inlet control valve (40) closing spring bias on its valve closure element (21), directed from the larger diameter of its valve seat taper towards its smaller diameter; the fluid connection between the high pressure inlet control valve (40) and the nozzle valve assembly (1) also being connected to the input of a residual pressure discharge control valve (35); the residual pressure discharge control valve (35) being oriented so that its input pressure likewise assists in holding its valve closure element (21) closed, which is operable to open at nearly the same instant that the high pressure inlet control valve (40) is closed by de-energization retraction of said push-only coupler (42); the de-energization retraction of said push-only coupler (42) allowing the residual pressure contained between the fully closed high pressure inlet control valve (40) and the spring assembly (20) biased closed but ejecting nozzle valve assembly (1) to instantly drop to a level below the nozzle valve assembly (1) closure pressure to a preferably regulated fluid medium boiling prevention pressure above the fuel vaporization pressure at the injector working temperature in the case of liquid fuel by the optional anti-boiling pressure regulator (44); the residual pressure drop being effected by opening of the residual pressure discharge control valve (35) by its mechanical linkage to the pull-only coupler (37) io connected by a shaft connection axially passing though the high pressure inlet control valve (40) to the push-only coupler (42) at its opposite end; the shaft connection axially passing though the high pressure inlet control valve (40) to the push-only coupler (42) causing the valve closing bias spring assembly (20) of the high pressure inlet control valve (40) to overpower the weaker valve closing bias is spring assembly (20) pressure of the oppositely oriented residual pressure discharge control valve (35), so that while the high pressure inlet control valve (40) (stronger bias) is normally closed, the residual pressure discharge control valve (35) (weaker bias) is pulled and held open against its spring assembly (20) by the more powerful spring assembly (20) of the former, except when the former is overpowered via the push-only coupler (42) by the high-speed actuator (41), forcing the high pressure inlet control valve (40) open, and releasing the residual pressure discharge control valve (35) SO that it closes by its own relatively weakest spring assembly (20), preferably insuring by a pull-only coupler (37) pull coupler linkage gap (45) that no force is applied to said control valve while said actuator (41) is energized despite normal tolerance changes including limited valve seat (25) wear.
25. 25. A high speed actuator, the high speed actuator being operable to actuate a fluid medium metering valve system of energize to meter type according to claim 15, comprising a control valve (35, 40) according to claim 12 or 13, the high speed actuator comprising at least one of a solenoid, piezoelectric, or similar high-speed actuator.
26. 26. A solenoid, piezoelectric, or similar high-speed actuator (41) actuated metering valve system of energize to inject type according to claim 23 in fluid medium communication with its nozzle valve assembly (1), said metering valve system being either structurally integral to, or structurally discrete from the corpus of the injector-igniter.
27. 27. A piezoelectric stack (49), characterized in that its fixed end has a pivoting support and its moving end is biased, supported, and centered by a parallel stack of one or more Belleville springs (24) as claimed in Claim 2.
28. 28. A fuel injector, comprising any of the preceding elements of claims 21 -27, comprising a means for promoting flash boiling of the injected fuel spray after it is sprayed into the combustion chamber, while maintaining its liquid state within the nozzle valve outside of the injection phase of its injection cycle characterized by any one of: a controlled source of heating in concert with a heating control means to limit the flash boiling temperature of the fluid medium within the nozzle valve prior to injection to io above a minimum foreseeable flash-boiling working temperature as required for its flash boiling after it is injected into the combustion chamber, and preferably also to below a maximum allowable temperature; a pressure control means to maintain the fluid medium within the nozzle valve above the vapor pressure of the fluid medium during the part of the injection cycle when is the fluid medium is not being injected.