The present invention relates to a direct injection injector for an internal combustion engine, and particularly to a direct injection injector nozzle valve assembly for a fluid medium. By the term "fluid medium" is meant a medium which is gaseous or liquid, or consists of a gaseous and liquid medium mixture. Specifically in the context of the present invention the term "fluid medium" means liquid fuel, gaseous fuel, a mixture of liquid and gaseous fuel, water, or a mixture of water and fuel. Although the inventive direct injection injector nozzle valve assembly is primarily intended for fuel injection applications, it is obvious to a person skilled in the art that the present inventive nozzle valve assembly is also applicable elsewhere where need arises for the transmission of a fluid medium through a nozzle valve which may be closed and opened.

PRIOR ART

From United States patent US 3,995,813 (published 07.12.1976) is a known internal combustion engine piezoelectric fuel injector of generally traditional construction, containing channels for a fluid medium (i.e. fuel), a valve seat, a needle-shaped valve closure element, a spring system comprising two biased Belleville springs which act upon the end of the valve closure element remote from the valve seat, thereby pressing the other end of the valve closure element into its valve seat, and a piezoelectric element to move the valve closure element away from its seat, opening said valve assembly.

The alignment of the known pintle valve closure element of patent US 3,995,813 is neither stable nor continuous, because the valve closure element, which in the present instance is a valve needle, has continuous support only at the remote end from its valve seat, enabling free radial movement of its valve seat end while the nozzle valve is open. Therefore, while the pintle valve is in its open state, the valve closure element is supported at the remote end from its valve seat, which fails to ensure the alignment/centering of the valve closure element; and therefore the motor vibration and the dynamic flowing fluid medium (fuel) displace the valve closure element aside from its central position, creating thereby an axial displacement of the valve seat end of the valve closure element in relation to the valve seat, and its wear.

United States patent US 4,553,059 (published 12.11.1985) describes a piezoelectric pump injector, which comprises an injector nozzle valve assembly in its injector nozzle tip part extending toward the internal combustion engine combustion chamber, which comprises a fluid medium (i.e. fuel) channel, spring assembly, valve seat and valve closure element.

The basic shortcoming of this construction is that, in light of the necessity for making the nozzle tip part slender, its comprising spiral spring, being of traditional nozzle valve assembly spring assembly construction, is of excessive diameter. Also, the sufficient and continuous centering of the valve closure element with respect to its valve seat is not supported by the construction of the nozzle valve assembly, which may lead to premature wear of the nozzle valve assembly.

In United States patent US 7,357,338 (published 15.04.2008) is described a gaseous fuel injector whose nozzle valve assembly valve closure element or injector needle, is centered with respect to the valve seat by supports joined laterally to the pintle which may be flexed such that the injector needle in its nozzle valve assembly may be nudged axially away from its valve seat.

The basic construction deficiency of the known fuel injector nozzle valve assembly of patent US 7,357,338 consists in the inaccuracy of the aligning mechanism of its relatively long and massive pintle valve closure element, in which the pintle valve supporting spring assembly is situated at a distance from the nozzle tip part of the injector nozzle containing the valve seat. Engine operational vibrations may cause the displacement of the unsupported end of the valve closure element from its center, upon its opening, creating premature wear of the valve seat and its receiving valve closure element, causing leaks. The relatively large length of the valve closure element, and the relatively large distance between its valve seating end and the supports of the valve closure element pose problems for economical production from the standpoint of precision. DISCLOSURE OF INVENTION

The object of the present invention is to provide a direct injection injector employing an improved nozzle valve assembly. Specifically its object is to provide a direct injection injector nozzle valve assembly construction enabling miniaturization of this assembly through simplified and improved construction to a degree enabling the compact combination of the direct injection injector with other devices, such as for example transducers, ignition plugs, etc., or with other direct injection injectors for the simultaneous employment of multiple diverse fluid media.

More specifically, the object of the invention is to provide an internal combustion engine direct injection injector for spraying a fluid medium into an internal combustion engine combustion chamber, in which the direct injection injector comprises an injector nozzle tip part penetrating the engine into the combustion chamber, which is at least by its end surface in immediate communication with the internal combustion engine combustion chamber.

Said direct injection injector comprises a nozzle valve assembly, comprising at least a spring assembly, a valve seat, and a valve closure element. The nozzle valve assembly valve closure element is pressed against its valve seat by the biased spring assembly (cf. claim 1 ).

In addition, the direct injection injector comprises at least one fluid medium channel between the pressure source of the fluid medium and the valve seat (cf. claim 1 ).

The present invention is characterized in that a spring assembly comprising at least one Belleville spring, along with the valve seat and the valve closure element, is situated in the internal combustion engine penetrating part of the direct injection injector nozzle tip part, wherein the valve closure element is continuously aligned with respect to the valve seat axis by means of said spring assembly, (cf. claim 1 ).

Thus in the simplest embodiments, the present fuel direct injection injector may work in any of its preferred embodiments operated by an external piezoelectric (or other type) fuel metering valve connected to a high pressure fuel rail or other high pressure fuel source. In application of the inventive solution to conventional diesel or gasoline direct injection solutions, this metering valve is incorporated into the body of the fuel injector, wherein connections with the fuel rail are provided by means of input pipe connections and electrical connections (for a piezoelectric fuel metering valve), eliminating need for a fuel return flow connection, in addition to which are fuel channels connecting the high- speed piezoelectric fuel metering valve to the inventive nozzle valve assembly in the fuel injector nozzle tip part. These fuel channels may take multiple route(s) to the nozzle valve, including a central path through the valve closure element, paths through openings in the valve Belleville springs and/or their spacer elements, or paths around the Belleville spring stack through the wall of its housing (cf. claims 1 , 23, 24). Minimization of the compressible volume of these channel(s), including location of the piezoelectric operated fluid medium metering valve optimally distanced to the nozzle valve, would insure unprecedented high speed fuel injection operation without need for fuel return channels, in a system of unparalleled simplicity due to the extreme light weight and miniature dimensions of the simple parts between the piezoelectric fuel metering valve and the injector nozzle tip part. The spring assembly of the present inventive direct injection injector nozzle valve assembly exploits the unique Belleville spring characteristic curve, which in contrast, for example, to the linear characteristic curve of the common cylindrical spiral spring, is conditionally S-shaped (cf. claim 20; FIG 8). A Belleville spring characteristic curve, or simply spring characteristic, is a graphical expression of the Belleville spring stiffness in a coordinate system in which the force is plotted along the vertical axis, and along the horizontal axis is plotted the spring displacement determined by said force during spring compression. Particulars of the Belleville spring characteristic curve are known to persons skilled in the art, and do not require more detailed explanation. The Belleville springs of the inventive nozzle valve assembly are advantageously exploited for alignment and centering of the valve closure element with respect to its valve seat axis.

Common practice in the state of the art continues to use relatively massive pintle valves. The infrequently used poppet valves are likewise massive. By inventive miniaturization the present invention practically eliminates massive nozzle valves whose operation is slowed, and their wear accelerated, due to their relatively great mass and inertia. Instead, the present invention utilizes lightweight inward or outward opening poppet valves often containing fluid channels, further reducing the mass. Some present invention embodiments eliminate even the usually lightweight and preferably hollow slender and short valve closure element stem shaped parts, resulting in even more reduction of nozzle valve mass, increasing the speed of nozzle valve parts and reducing their wear.

In the present invention, miniaturization is synergistic with simplicity, and both contribute to higher speed, higher precision, and more intricately detailed minutely computer controlled operation of the nozzle valve, the basis for improved fuel efficiency and reduced emissions.

Furthermore, in response to the drive for greater fuel efficiency with reduced emissions, the state of the art has tended to ever increasing complexity and multiplicity of nozzle valve control mechanisms; a large part of which comprise fuel injector improvements aimed at forcing the massive nozzle valve to act with more speed, precision, and complex adaptation to the extensive demands of a complex and varying combustion process both within a single combustion cycle, as well as throughout the entire engine power range in which combustion characteristics and demands vary greatly. Instead of combating the mass of the nozzle valve by such complex means, the present invention eliminates both the mass and complex nozzle valve speed-up and miniaturization solutions due to this mass, based on the introduction of a Belleville spring stack in the nozzle valve situated in the injector nozzle tip part.

Thus unusually simple injectors are employed which need few if any complex control features as in the state of the art. The preferred embodiments of the inventive nozzle valve assembly respond practically without delay to changes in fuel pressure as governed by a piezoelectric or other technology metering valve. Parts of this metering valve may also reside in the injector nozzle tip part upstream from the nozzle valve to minimize fuel compression delay, or they may be completely separate from the injector, connected by tubing or other fuel channels, offering unprecedented engineering flexibility by miniaturization.

The state of the art is tending to increasing multiple injections per injection cycle by microprocessor control. The present simple and miniature invention is ideally suited for his trend by virtue of its speed and precision advantages, to almost completely transform injection control from the state of the art complex mechanisms within the injector to an unprecedented rapid and precise simple high-speed high pressure valve under microprocessor control, for example, connected to a high pressure fuel rail or other source of high pressure fuel, greatly increasing the possible number of injections per cycle precision tailored for the optimization of the multiple complex phases of each combustion cycle, increasing combustion efficiency, and decreasing pollution.

The miniaturization upon whose benefits the present invention is based is by no means a simple scale reduction of any prior art, but is founded on inventive steps based on a broad and deep understanding of the Belleville spring properties in combination with the effects of Belleville spring parallel stacking, which enables nozzle valve Belleville spring performance equivalent to or beyond that of substantially larger powerful coil springs (in consideration of high Belleville spring force combined with moderate or low Belleville spring stiffness), which is the key to precision control of the injector nozzle valve. Exploited as the basis for miniaturization are the two unique advantages of the Belleville spring: its unsurpassed compactness (due to very large Belleville spring stiffness), and its ability to be extremely compactly parallel stacked, multiplying the Belleville spring force by the number of Belleville springs in the stack in consequence of a very small increase of the Belleville spring stack thickness. The unrivalled concentration of force of the Belleville spring is achieved through limiting the Belleville spring stroke to unusually small values, which is no impediment to the use of Belleville springs in fuel injector applications. Therefore Belleville springs are uniquely suited for reduction in size, notably their diameter, since their parallel stacking compactly restores any force lost due to such miniaturization.

The nozzle valve precision as well as its self-aligning ability are based on the geometrical (mechanical) stability of this system due to the inventive Belleville spring's directly or indirectly aligning central support area of the valve closure element, which includes alignment support point (edge) 16 (cf. claim 18), being in close proximity, being less than the valve seat sealing surface diameter, is another unique aspect of the overall injector nozzle miniaturization in the preferred embodiments. Minimizing this proximity maximizes the stability and mechanical advantage (forces of leverage) which drives the nozzle valve self-aligning function. Thus compaction of the system, as a result of application of stacked Belleville springs, provides benefits of both nozzle valve speed and precision of control, working synergistically with the nozzle valve alignment function to ensure sealing of the nozzle valve during manufacture, or self adjustment of the nozzle valve, wherein both positive effects reinforce one another.

Due to the microscopic working stroke (displacement) of the nozzle valve closure element and its spring assembly Belleville spring or Belleville springs, which has typically been 100μm, the breadth of a human hair, but is consistently shrinking below 30μm as the state of the art has driven fuel injection pressures upwards, it is sufficient in some nozzle valve assembly embodiments to use smooth, non-corrugated Belleville springs, especially when the Belleville springs of the spring assembly are sufficiently thin and parallel stacked.

Its logical consequence is use of two special Belleville spring corrugations in embodiments of the invention which optimally increase Belleville spring resilience, permitting reduction in Belleville spring diameter relative to the equivalent non-corrugated Belleville spring diameter, or increase in Belleville spring cone height and working stroke

(displacement), or a combination of these, without loss of Belleville spring force.

Whereas each Belleville spring of the nozzle valve spring assembly is supported through its outer support area and central support area (which are of a flat ring shape), and whereas the most effective method of employment of Belleville springs from a compactness viewpoint is the so-called parallel stacking (serial stacking is not excluded, but it does not offer optimal advantages), avoidance of friction calls into play the use of "of one piece" (i.e. integral) or discrete spacer elements (preferably spacer washers), disposed respectively between the Belleville spring central support area and outer support areas, of Belleville springs stacked one upon the other, notwithstanding the microscopic working stroke of the Belleville spring. And to provide pressure equalization between the inter-spring voids and the ambient injection pressure pulses, fluid channels may be disposed in the radial and/or axial directions in the inner and outer spacer elements (preferably spacer washers) or Belleville springs (claim 23). Channels may also be annular, which unite vertical channels. Pressure equalization apertures may be disposed in Belleville springs throughout the extent of the Belleville spring stack, which may simultaneously serve the nozzle valve as fluid medium channels through the Belleville spring stack. Moreover, fluid medium channels may pass outside of the Belleville spring stack, by way of the wall of the injector body. The guiding/directing control of the valve closure element with respect to the valve seat axis by means of the Belleville spring stack disposed on the valve closure element achieves a synergistic effect in that the valve closure element does not need separate supports/bushings for its alignment and control with respect to its valve seat axis. Such an operational principle controlling the alignment of the valve closure element with respect to its valve seat axis resembles the working principle of the multiple frictional disc pressure clutch, in respect to which emerges another complementary useful effect in which spacer washers between the Belleville springs assist in the control of the valve sealing element alignment with respect to the valve seat axis, when they are provided with radial freedom of movement. This second unexpected effect, which is based on the valve closure element alignment and centering effect in the nozzle valve, is realized without need for additional parts by simply enlarging the diameter of the opening in the central support areas of the stacked Belleville springs in order to provide a certain radial freedom of movement to the nozzle valve closure element stem-shaped part and its associated spacer washers. This axial alignment and centering of the valve closure element in its seat enables precision alignment during nozzle valve manufacture and continuous self- alignment in nozzle valve assembly operation.

But the self-centering effect is ensured only then if there is enough supporting surface or mutual contact surface between the spring assembly and the valve closure element; or alternatively if the end of the stem-shaped part remote from the valve seat is sufficiently distant from the valve seat, and is held centered by a close fit in the opening in the central support area of the remote Belleville spring or the opening in its associated central spacer washer, and the pressure of the spring assembly holds the valve closure element with radial freedom of movement, either by means of a moving spacer washer, or by pressure against the valve closure element. In order to achieve adequate alignment, the valve closure element's stem-shaped part of the latter described embodiment must be either precisely centered, or must be at a sufficient distance from the valve seat.

In the case of a nozzle valve with an inward opening valve closure element, in distinction to a nozzle valve with an outward opening valve closure element, Belleville spring nearest to the valve seat exerts a force immediately against a support surface (namely, the central forcing surface) of the valve closure element, which holds the tip of the valve closure element in the valve seat.

For best performance of both factory alignment in nozzle valve manufacture as well as valve closure element self alignment, the average distance between the valve seat and the nearest point to it of valve closure element support should be minimized. This dimensional reduction and the overall goal of miniaturization are mutually supportive (cf. claim 18; FIG 1 , 2, 9-15).

In embodiments in which the valve closure element does not comprise a stem- shaped part, the orienting effect of the Belleville spring stack consists in that the valve closure element is held centered while maintaining its orientation in both vertical as well as the horizontal directions.

The valve closure element is held in at least horizontal alignment by means of pressure contact between two horizontal surfaces, insuring that the valve closure element alignment is at least parallel to the valve seat axis, whereupon due to vibration the valve closure element moves freely toward its valve seat while sliding radially toward its correct position (center) in the valve seat.

Inward and outward opening nozzle valves according to the present invention are adapted by very simple modification to inject a swirling (spiral) fuel spray into the combustion chamber.

BELLEVILLE SPRING PRINCIPLES

A correct and thorough understanding of the Belleville spring non-linear characteristic curve FIG 8, (including the Belleville spring cone height to thickness ratios), especially the spring characteristic non-linear snap-over region, is essential for understanding the present invention, beyond the distinction between spring force and its first derivative with respect to displacement, i.e. spring stiffness. Such understanding reveals that reduction of Belleville spring thickness decreases its stiffness, and therefore stretches its S-shaped characteristic curve horizontally along the displacement axis, and also reduces the curve height along the force axis. By thinning the spring, the Belleville spring characteristic curve shrinks lower (in force) and stretches longer (in displacement). Consequently any method of reducing the Belleville spring stiffness (e.g. by corrugation or cutting slots) has an effect analogous to reducing the Belleville spring thickness, in that the curve is similarly stretched along the horizontal axis. However the measure of the efficiency of the Belleville spring reduction of stiffness is measured by the degree to which the force of the Belleville spring is preserved (along the vertical axis). By this criterion, corrugation is the most effective method for reducing Belleville spring stiffness, because it best preserves the original Belleville spring force at any point along the horizontally stretched S-shaped characteristic curve. Cutting of slots in the Belleville spring (as in US patent 6,705,813) comes next in effectiveness, although it could prove even worse than making the Belleville spring thinner. But corrugation and reduction of the Belleville spring thickness most effectively increase Belleville spring service life. Belleville spring parallel stacking has no effect on the horizontal features of the spring characteristic, but increases the vertical curve values and slope values by the number of Belleville springs in the stack. Also, Belleville spring service life is unaffected by stacking. Also, a parallel stack of thin or corrugated Belleville springs has a characteristic curve of considerably less slope than that of a single Belleville spring of equivalent thickness, offering significant advantages over the equivalent thickness single Belleville spring for Belleville spring control purposes regardless of location along the characteristic curve (namely even outside of the preferred non-linear snap-over region where the slope of the characteristic curve can be zero or negative). Therefore the present invention optimally exploits compactly parallel stacked thin Belleville springs of small diameter.

Another characteristic of the present invention is that when using a plurality of identical Belleville springs in a stack, those springs do not act as Belleville springs placed in series on top of one another, but as as Belleville springs placed in parallel next to one another. This is achieved by stacking the Belleville springs relative to one another in the same orientation, wherein spacer elements are placed between the Belleville spring central support areas and outer support areas, whereby the pressure of each individual Belleville spring is transferred from the Belleville spring central support area and outer support area to its respective neighboring support surface, respectively to the central forcing surface of the valve closure element and the nozzle tip part of the injector.

This enables the use of stacked multiple Belleville springs of diminished size (diameter and Belleville spring thickness) and diminished force in order to achieve increased pressure of the spring assembly. Thus a stack of identical reduced diameter Belleville springs may be used in the spring assembly instead of a single Belleville spring of large diameter and thickness to achieve the same force.

However, it must be noted that Belleville springs of equal diameter have been under discussion. If the diameter of a single thicker Belleville spring were increased, it would have performance equivalent to a stack of thinner Belleville springs of equal total thickness, but smaller diameter. The greater effectiveness of a stack of thinner Belleville springs over a single larger diameter and thick Belleville spring of equivalent spring characteristic is evident.

None of these nozzle valve assembly Belleville valve spring miniaturization and performance advantages (in relation to traditional coil springs in general, or even in the sole exception of US 3,995,813) have previously been exploited by persons skilled in the art, because they have not been well understood.

Annular corrugation of the Belleville spring emanating from its central axis which comprises a single wave peak directed from the Belleville spring surface either upward or downward (generally termed a "single wave peak"), which covers the entire free Belleville spring surface, may be optimal for most embodiments of the nozzle valve assembly spring assembly. A few examples of individual Belleville springs which are corrugated are known to the art, but which state of the art solutions are not used as parallel stacked, as for example computer keyboard Belleville springs (JP 3,199,729 A; US 5,140,733), or series stacked Belleville springs (GB 465,236 A). These Belleville springs all contain dense corrugation, in which are more than three wave peaks, and in consequence of which these Belleville springs function practically as elastic membranes, incapable of creating strong forces without deformation. Such Belleville spring embodiments are not intended for producing high Belleville spring forces.

Belleville springs exhibit a rising stiffness gradient towards the axis, becoming more rigid with decreasing radius, all other parameters remaining constant. This gradient is most pronounced (steep and uniform) and effective in the case of a single peak Belleville spring corrugation, where increased stiffness is needed near the Belleville spring center to concentrate and structurally support the Belleville spring energy mostly stored in the progressively more flexible and larger outer surface area of the Belleville spring, where increased structural size compensates for reduced stiffness, spreading the load. In other words, the increased central stiffness of the annular Belleville spring geometry has a radially progressive useful effect because the central part is able to structurally support force without increased deformation relative to the situation where the central part would have stiffness similar to that of a region of the Belleville spring further from the central part. The annularly corrugated Belleville spring axial stiffness gradient with respect to radius and axial force falls sharply with increasing Belleville spring corrugation peak count. For the single peak corrugation, its larger radial stiffness gradient is due to the inner radius of bending of the corrugation's annular wave peak being much smaller towards the central support area of the Belleville spring than towards its outer support area. This radial difference, or rather its ratio, is for any specific corrugation, a measure of the Belleville spring axially directed flexibility, or the curvature sharpness of any given corrugation, which progressively diminishes with increasing corrugation peak count. Of course, this effect also diminishes as the corrugation flattens. Therefore, for small Belleville spring displacement applications such as fuel injectors, it is advantageous to exploit this Belleville spring geometry based high radial stiffness gradient and spring force level most pronounced in the single peak Belleville spring corrugation, and reduced but still useful in the two peak corrugation, but losing advantage for higher order corrugations due to steep drop-off in spring force. The previously described useful effect of the Belleville spring force concentrating high Belleville spring radial stiffness gradient consists in achieving by the most compact means the greatest spring force in combination with the greatest elasticity of the Belleville spring, in consequence of which the invention author's single or double wave peak Belleville spring corrugation appear to be the most useful geometric shapes of Belleville spring corrugations.

Moreover reduction of the Belleville spring thickness as well as application of corrugation extends its service life.

So a stack of corrugated and thin Belleville springs stacked in parallel achieve a longer service life in comparison to a single Belleville spring of equivalent stiffness and force, and the stacked Belleville springs are of significantly smaller outer diameter, which essentially benefits the miniaturization of the entire spring assembly. Also, slight Belleville inter-spring contact in compact stacking is not anticipated to affect their performance.

The single wave peak corrugation geometry propagating from the Belleville spring central axis is optimal for application to the snap-over region of the Belleville spring characteristic curve, minimizing the loss of the original force of the equivalent non- corrugated Belleville spring (minimizing the penalty of corrugation), while at the same time making it substantially more resilient.

A Belleville spring having a two peak corrugation, is more flexible than the single peak corrugated Belleville spring, and in the case of a biased Belleville spring, the wave- shaped profile of such a corrugation likewise begins and ends at points where the tangent to the profile is at a zero degree angle to the Belleville spring central support area or its outer support area.

The more resilient double peak corrugated Belleville spring may be preferable for use as biased in the spring characteristic region prior to the mentioned snap-over region.

However, also in the case of a Belleville spring biased in this spring characteristic region, use of the single peak corrugation profile may be preferred due to its greater simplicity and spring force, offering generally adequate resilience. In biasing the Belleville spring beyond the spring characteristic snap-over region, Belleville spring fatigue and resulting Belleville spring breakage become problematic. Although both corrugation profiles (one or two wave peaks) are in practice interchangeable, possibly they are optimal according to their differing characteristics for operation in their respective preferred regions of the

Belleville spring S-shaped characteristic curve. Additional Belleville spring corrugation profile wave peaks (more than two) offer no advantage for high force Belleville spring applications, such as for fuel injectors. In applications requiring high Belleville spring force, the use of a corrugation containing more than two wave peaks is not advantageous, because in adding to the number of wave peaks of a corrugation, force drops drastically.

In the non-linear S-shaped snap-over characteristic region, Belleville spring axial displacement conditioned by change in the force along the spring axis enables operation of the Belleville spring in a so-called snap-over mode, in which a relatively small change in pressure corresponds to a relatively large change in displacement (cf. claim 20; FIG 8).

In the so-called snap-over regime of the Belleville spring enabled by its S-shaped characteristic curve, the Belleville spring stiffness is sufficiently low, close to zero, or even negative to achieve displacement of the Belleville spring by means of a relatively small force/pressure change. The advantage of reduced spring stiffness is correspondingly increased injector nozzle control system accuracy and precision without added complexity or manufacturing cost. Operation in the Belleville spring negative stiffness region may under certain circumstances increase speed and effectiveness of the Belleville spring operation.

In order to achieve high Belleville spring force in conjunction with low Belleville spring stiffness), an embodiment of the present invention features an annular and wave- shaped corrugation symmetric about the Belleville spring central axis, whose waves propagate from the Belleville spring axis radially, as for example annular waves resulting from the dropping of a stone onto a smooth surface of water. Drawings FIG 1 and 6 (showing the Belleville spring of FIG 6 respectively in its compressed and relaxed states) or 2 and 5 (showing the Belleville spring of FIG 5 respectively in its and compressed and relaxed states) present respectively schematic views of strongly exaggerated in amplitude cross sectional views of single peak corrugations whose peaks are oriented oppositely. FIG 7 presents a schematic, strongly exaggerated in amplitude cross section view of a double peak corrugation. Corrugations that are of high relative amplitude make a Belleville spring many times more rigid than the equivalent low amplitude or non-corrugated Belleville spring. In addition, this kind of illustrative wave amplitude exaggeration creates bends in the relaxed form of the corrugation which add small corrugation wave peaks at the Belleville spring outer support area and central support area. Correct and practically useful Belleville spring corrugation waves (always defined in the relaxed spring mode) with one or two wave peaks which cover the entire Belleville spring free surface would be scarcely noticable, and consequently poor examples for illustration. A normal Belleville spring in its uncompressed state as shown in FIG 9, is shown in its compressed state in cross sectional drawing FIG 10 (and similarly FIG 11 - 15) having a straight line profile, where actually the uncompressed straight line profile would appear as a double peak wave profile under compression.

A Belleville springs is substantially in the form of a truncated cone, whose cone peak angle is relatively large, such that the base diameter of the truncated cone is relatively large compared to its height. The Belleville spring or springs of the spring assemblies of the nozzle valve of the present invention are furnished with an annular corrugation symmetric about the Belleville spring central axis.

A BRIEF DESCRIPTION OF THE DRAWINGS

The invention is further described in detail via examples of embodiments by reference to the accompanying drawings, wherein:

drawing FIG 1 schematically depicts the inventive direct injector nozzle valve assembly, having a nozzle valve inwardly opening valve closure element comprising a separate stem-shaped part which in turn aligns the valve closure element with respect to its valve seat axis;

drawing FIG 2 schematically depicts the inventive direct injector nozzle valve assembly, having a nozzle valve outwardly opening valve closure element, 19.7 whose alignment and centering with respect to its valve seat axis is accomplished by means of spacer washers held between the central support areas of Belleville springs of the spring assembly according to the principle of a clutch, said stem shaped part being held tightly in the central holes of said washers; drawing FIG 3 schematically depicts a typical Belleville spring;

drawing FIG 4 schematically depicts a cross section of the typical Belleville spring of FIG 3;

drawing FIG 5 depicts an inventive Belleville spring oriented in the same direction as the Belleville spring of FIG 4, having a wave shaped corrugation, in which the wave peak of the corrugation is directed in reference to the inner surface of the unbiased Belleville spring towards its outer surface, or approximately "upward";

drawing FIG 6 depicts an inventive Belleville spring oriented in the same direction as the Belleville spring of FIG 4, having a wave shaped corrugation, in which the wave peak of the corrugation is directed in reference to the outer surface of the unbiased Belleville spring towards its inner surface, or approximately "downward";

drawing FIG 7 depicts an inventive Belleville spring embodiment in its compressed state having a wave-shaped corrugation consisting of two wave peaks;

drawing FIG 8 schematically depicts a typical Belleville spring S-shaped characteristic curve comprising a non-linear snap-over region;

drawing FIG 9 schematically depicts the Belleville springs of the inventive direct injection injector nozzle valve assembly situated in the nozzle tip part before their compression; drawing FIG 10 schematically depicts the nozzle valve assembly of FIG 9 after compression of the Belleville springs wherein alignment of the valve closure element operates similarly to that presented in drawing FIG 2;

drawing FIG 11 schematically depicts the inventive direct injection injector nozzle valve assembly having a nozzle valve outwardly opening valve closure element (cf. FIG 2); drawings FIG 12 to 15 schematically depict various inventive embodiments of the direct injection injector nozzle valve assembly having a nozzle valve inwardly opening valve closure element without the stem-shaped part (FIG 13 to 15), or including its stub (FIG 12).

PREFERRED EMBODIMENTS (PE) LISTED

PE I: An embodiment of the invention wherein the Belleville spring comprises an annular wave-shaped corrugation symmetric about the Belleville spring central axis, wherein the Belleville spring annular wave-shaped corrugation comprises at least one wave peak (cf. claim 2; FIG 5,6).

PE II: An embodiment of the invention wherein the Belleville spring comprises an annular wave-shaped corrugation symmetric about the Belleville spring central axis, wherein the Belleville spring annular wave-shaped corrugation comprises either one or two wave peaks (cf. claim 3; FIG 5, 6, 7). PE III: An embodiment of the invention wherein the Belleville spring corrugation comprises at least one peak, which is oriented from the outer surface of the relaxed Belleville spring towards the inner surface of the Belleville spring (cf. claim 2; FIG 1 , 4, 6). PE IV: An embodiment of the invention wherein the Belleville spring corrugation comprises at least one peak, which is oriented from the inner surface of the relaxed Belleville spring towards the outer surface of the Belleville spring (cf. claim 2; FIG 2, 4, 5). PE V: An embodiment of the invention wherein the Belleville spring comprises an annular corrugation, symmetrical about the Belleville spring central axis, wherein the transition of the Belleville spring wave-shaped corrugation to its outer support area and/or the Belleville spring central support area occurs at the point of the biased spring wave shape cross section profile where its tangent is normal to the Belleville spring central axis (cf. claim 4; FIG 1 , 2, 9, 10).

PE Vl: An embodiment of the invention comprising at least two stacked Belleville springs in the spring assembly (cf. claim 5). The axes of the individual stacked Belleville springs coincide with the axis of the stack.

PE VII: An embodiment of the invention which specifies that adjacent parallel-stacked Belleville springs must be nearly identical, which simplifies and optimizes the function and manufacture of the invention, and supports the miniaturization of the spring assembly, where like-oriented Belleville springs must fit together most compactly (cf. claim 6).

PE VIII: The spring assembly of an embodiment of the invention comprises in its stack at least two Belleville springs, wherein between each successive pair of Belleville springs is at least one spacer element. A spacer element is required for maintaining separation between the surfaces of the Belleville springs in order to prevent their mutual friction and to set the Belleville springs to work in a parallel configuration (cf. claim 7).

PE IX: The spring assembly of an embodiment of the invention comprises in its stack at least two (identically oriented) Belleville springs, wherein between each successive pair of Belleville springs are two spacer elements, of which one spacer element is disposed between the Belleville spring outer support areas, and of which the other is disposed between the central support areas of the Belleville springs (cf. claim 8; FIG 1 , 2, 9-15). PE X: In an embodiment of the invention at least one spacer element includes a spacer washer (cf. claim 9; FIG 9).

PE Xl: In another preferred embodiment of the invention at least one spacer element includes an annular spacer thickening formed on the surface of the Belleville spring (cf. claim 10).

PE XII:The spring assembly of an embodiment of the invention comprises in its stack at least two identically oriented Belleville springs, wherein between each successive pair of Belleville springs is at least one spacer washer as a spacer element, wherein the nozzle valve closure element is pressed against its valve seat by pressure on the valve closure element central forcing surface as caused by the spacer washers disposed between the central support areas of the Belleville springs of the spring assembly (cf. claim 11 ; FIG 1 , 2, 10-15).

PE XIII: A preferred embodiment comprises a spacer washer disposed between the central support areas of two Belleville washers centered radially in relationship to the central support area of at least one Belleville spring adjacent to the spacer washer by means of a step disposed on the spacer washer; or in other words, the Belleville spring's central support area hole is situated on this step such that the spacer washer is held in place between the Belleville springs of the Belleville spring stack of the spring assembly with respect to the central support area of the respective Belleville spring. The Belleville spring may be disposed upon this step either with play, or tightly (cf. claim 12; FIG 2, 12, 13, 14, 15).

PE XIV: A preferred embodiment of the invention the Belleville spring stack of the spring assembly comprises at least one spacer washer aligned to the valve seat axis, having radial freedom of movement relative to the central axis of the nozzle tip part, where in turn the valve closure element is aligned and centered relative to the valve seat axis by said spacer washer (cf. claim 13; FIG 2, 10, 11 , 12, 14, 16).

PE XV: A preferred embodiment according to claim 13, wherein said spacer washer is provided a dowel-shaped part, their combination being a "dowel washer", which aligns and centers valve closure element with respect to the axis of valve seat axis, wherein the dowel shaped part of dowel washer may comprise a fluid medium channel between spring assembly and valve seat (cf. claim 14; FIG 14).

PE XVI: An embodiment of the invention wherein the valve closure element is aligned relative to the valve seat axis by direct or indirect contact between the Belleville spring stack and the valve closure element such that alignment and centering movement of the valve closure element with respect to the axis of valve seat is limited to the radial direction relative to the Belleville spring stack axis (cf. claim 15; The embodiments in FIG 1 , 13, 15 are governed by the principle of claim 15. The principle of claim 15 works as a secondary effect in the embodiments of Fl G 2, 10, 11 , 12, and 14).

PE XVII: An embodiment of the invention according to claim 15, wherein said Belleville spring, which directly or indirectly provides aligning contact to the valve closure element with respect to the valve seat axis, is provided with an annular central step by its central support area, by means of which the valve closure element is held and centered with slack for radial freedom of displacement, limiting tipping (inclination) of the valve closure element in its valve seat. The angle of the step, which in drawing FIG 15 is 45°, may be any angle which practically prevents excessive tipping of the valve closure element in its valve seat. And notwithstanding the depiction in FIG 15 of the step as a flange, the step is not required to be bent into the Belleville spring metal, but may be otherwise realised, for example by an annular part rigidly connected to the surface of the Belleville spring (cf. claim 16; FIG 15).

PE XVIII: An embodiment of the invention wherein the valve closure element is aligned to the valve seat axis by direct or indirect contact between the valve closure element and separate stem part of the valve closure element disposed between valve closure element and Belleville spring stack, and aligned by the Belleville spring stack to the valve seat axis, such that centering movement of the valve closure element with respect to valve seat 4 is limited to the radial direction relative to the axis of the Belleville spring stack. The stem-shaped part of the valve closure element is separate from the valve closure element, being parts which are not of one piece, (cf. claim 17; FIG 1 ).

PE XIX: An embodiment of the invention wherein to achieve nozzle valve stabilisation, maximisation of operational precision, and nozzle valve assembly miniaturization, the distance from a point of nozzle valve closure element alignment support located on a Belleville spring in the Belleville spring stack, to the plane of the largest diameter ring of nozzle valve sealing contact made by the valve closure element and its valve seat, is less than the diameter of that ring (cf. claim 18; FIG 1 , 2, 9-15).

PE XX: An embodiment of the invention wherein the direct injection injector spring assembly is biased into Belleville spring characteristic curve region preceding its snap- over region (cf. claim 19; FIG 8).

To increase Belleville spring elasticity without losing its force (which includes avoidance of exceeding the yield limit of the Belleville spring steel: namely its deformation) under certain conditions, a single or a double peak corrugated Belleville spring is preferable for use as biased in the spring characteristic region prior to the mentioned snap-over region. PE XXI: An embodiment of the invention wherein the spring assembly is biased into the beginning part of the spring assembly Belleville spring characteristic curve snap-over region, and preferably within it (cf. claim 20; FIG 8). To this end the spring assembly is biased to at least the beginning of the Belleville spring spring S-shaped characteristic curve non-linear snap-over region by displacing the central support area of the Belleville spring along its central axis to approximately 30% to 50% of full compression where the spring force reaches its ideal near horizontal peak force region immediately prior to the snap-over region's falling force. And the beginning point of the snap-over region is prior to this, or approximately at 25% full compression. 100% full compression is reached when the plane of the Belleville spring central support area coincides with the plane of the 5 Belleville spring outer support area. Therefore drawings FIG 1 , 2, 10, 11 , 12, 13, 14, and 15 intended to show Belleville springs biased in the snap-over region actually show compression beyond this, even beyond the 100% full compression point where almost all Belleville springs experience deformation damage.

PE XXII: An embodiment of the invention wherein the valve closure element of the direct io injection injector nozzle valve assembly comprises a stem-shaped part and its central forcing surface extending perpendicularly away from said stem shaped partof the valve closure element, upon which is disposed at least one Belleville spring of the spring assembly in a stack oriented perpendicular to the stem-shaped part. (cf. claim 21 ; FIG 1 ,

2, 10, 11 , 12). In some embodiments the stem-shaped part of the valve closure element

15 may be separate from the valve closure element, being parts which are not of one piece.

PE XXIII: An embodiment of the invention in which the stem-shaped part of the valve closure element is absent. Poppet valves, as in the present invention, always embody a valve push-rod (ie. valve stem or pintle). Therefore the embodiments without valve pushrods are unique (cf. claim 22).

20 PE XXIV: An embodiment of the invention wherein at least one channel enabling the flow of a fluid medium in the space between two consecutive Belleville springs in the stack is disposed within at least one spacer element or Belleville spring. This is useful in order to equalize the pressure on the surfaces of the Belleville springs imposed by the dominant pressure of the ambient fluid medium of the nozzle valve spring assembly, in order to

25 avoid excessive undesirable deformations. (cf. Claim 23).

PE XXV: An embodiment of the invention wherein the stem-shaped part of the valve closure element comprises a fluid medium channel which opens between the spring assembly and the valve seat (cf. claim 24; FIG 1 , 2, 9-15).

PE XXVI: An embodiment of the inventive direct injection injector nozzle valve assembly 30 wherein the valve closure element, which is pressed against its valve seat by the biased spring assembly, opens the nozzle valve assembly by a displacement of the valve closure element from its valve seat toward the spring assembly and inwardly with respect to the nozzle valve assembly (cf. FIG 1 , 9, 10, 12-15), or by a displacement with respect to the nozzle valve assembly outwardly and away from the spring assembly (cf. claim 25; FIG 2,

35 11 ). PE XXVII: An embodiment of the invention wherein displacement of the valve closure element with respect to the valve seat by the control means of the direct injection injector nozzle valve assembly to open the nozzle valve assembly is realized by pressure applied by a fluid medium, an electromechanical drive, a mechanical drive, a hydraulic drive, or a piezoelectric drive (cf. claim 26).

PE XXVIII: An embodiment of the invention wherein the direct injector is intended for injection of a fluid medium, which may be liquid fuel, gaseous fuel, a mixture of liquid and gaseous fuel, water or a mixture of water and fuel, into a combustion chamber (cf. claim 27).

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

PREFERRED EMBODIMENTS (PE I - PE XXVIII) IN FUNCTIONAL CONTEXT

INTRODUCTION

Nozzle valve assemblies are at first divided functionally into two cateories: those having inwardly opening nozzle valve assembly valve closure elements, and those having outwardly opening nozzle valve assembly valve closure elements.

Although the choice of a specific Belleville spring corrugation may play a role in spring assembly optimisation according to the demands of technical conditions, in principle such a choice is without restriction, such that in all of the patent drawings of the present invention and preferred embodiments one may freely exchange any Belleville spring by another, regardless of the shape or thickness of its cone, its working (bias) force and position, or corrugation or absence of corrugation.

Also the choice of spacer elements is conditionally without restriction.

The nozzle valve assemblies having outwardly opening valve closure elements of

FIG 2 and FIG 11 do not embody mechanically functional differences, namely Belleville springs with or without corrugation (modifications of spring properties), and central spacer washers with or without steps which increase mutual metal surface contact, reducing wear.

The step in the spacer washers of the variants depicted in FIG 2 and 11 do not play an essential functional role.

Compared to outward opening valve closure element nozzle valve assemblies, the variants of inward opening valve closure element nozzle valve assemblies of FIG 1 , 9, 10, and 12-15 present significant mechanical and functional differences, in which the presence, absence or any choice of Belleville spring corrugation plays no role. Consequently, outward opening valve closure element nozzle valve assemblies constitute one category of preferred embodiments, presented in drawings FIG 2 and 11. And inward opening valve closure element nozzle valve assemblies constitute another category of preferred embodiments, in FIG 1 , 9, 10, and 12-15.

Furthermore, categories of preferred embodiments are divided functionally into three distinct groups according to claims 13, 15, and 17. Claim 13 comprises inwardly opening (FIG 10, 12, 14) as well as outwardly opening (FIG 2, 11 ) valve closure element nozzle valve assembly variants. And claims 15 and 17 deal only with inwardly opening valve closure element nozzle valve assembly variants. Consequently, preferred embodiments are divided into separate categories according to the opening direction of their nozzle valves, as well as according to the functional principles of claims 13, 15, and

17.

The first preferred embodiments category, A, would be the sole outward opening valve closure element nozzle valve assembly variant, presented in drawings FIG 2 and 11 , included in the working principle of claim 13.

The second preferred embodiments category, B, would include inwardly opening valve closure element nozzle valve assembly variants presented in Drawings FIG 9, 10, 12, and 14, embodying the working principle of claim 13.

The third preferred embodiments category, C, would include inwardly opening valve closure element nozzle valve assembly variants presented in Drawings FIG 13 and 15, embodying the working principle of claim 15.

The fourth preferred embodiments category, D, would include inwardly opening valve closure element nozzle valve assembly variants presented in Drawing FIG 1 , embodying the working principle of claim 17.

PREFERRED EMBODIMENTS CATEGORY Ω: EMBODIMENTS COMMON TO OR OPTIONAL TO ALL OF THE FUNCTIONAL CATEGORIES A, B, C, AND D

Whereas the movement of the nozzle valve is microscopic, imperceptible, there is no distinction between the static and dynamic views in the illustrations of the preferred embodiments.

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

All of the preferred embodimnt drawings FIG 1 , 2, 9-15 depict the inventive direct injection injector nozzle tip part 1 , wherein said nozzle tip part 1 is at least by its end surface 2 intended to be in immediate communication with an internal combustion engine combustion chamber. All of the preferred embodiment drawings FIG 1 , and 2, 9-15 depict only the part of the direct injection injector comprising the nozzle valve assembly, or more precisely the part of the injector nozzle tip part 1 which is directed into the combustion chamber.

The nozzle valve assembly comprises a fluid medium channel 3, the valve seat 4 and the valve closure element 5, and the spring assembly 7 of Belleville springs 6.

In drawings FIG 1 and 6 Belleville springs 6 of the spring assembly 7 of the nozzle valve assembly are depicted in their biased state, which will be discussed more fully below.

The axes of the individual stacked Belleville springs 6 coincide with the axis of the stack (i.e. spring assembly 7).

Valve closure element 5 is pressed by the biased spring assembly 7 against valve seat 4, and valve closure element 5 is aligned with respect to the valve seat axis by means of said spring assembly 7.

Valve closure element 5 comprises at least one channel 3 for a fluid medium. Other fluid medium channels 3 are not depicted in the interests of clarity. These comprise channels for conducting a fluid medium between the Belleville springs 6 and other fluid medium channels 3 which would be required in actual embodiments.

In all preferred embodiment drawings FIG 1 , 2, 9-15, a valve spring assembly 7 of Belleville springs 6 with valve seat 4 and valve closure element 5 are placed within the injector nozzle tip part 1 , which is at least by its end surface 2 in immediate communication with the combustion chamber of an internal combustion engine.

As is evident in drawings FIG 1 and 2, the Belleville springs 6 of the spring assembly 7 have an annular wave-shaped corrugation 8 symmetric about the central axis of Belleville spring 6. Moreover, Belleville springs 6 without corrugation 8 according to drawing FIG 3 are also used.

All embodiments depicted in drawings FIG 1 , 2, 9-15 comprise stacked Belleville springs 6 in their spring assemblies 7, in which between every two sequential Belleville springs 6 are two spacer elements 9 and 11 , concretely embodied as spacer washers 9 and 11 , wherein spacer washer 9 is situated between the outer support area 10 of the Belleville springs 6, and wherein the other spacer washer 11 is situated between the central support area 12 of the Belleville springs 6. The Belleville springs 6 are held separated from each other by spacer washers 9 and 11 to avoid friction. Instead of spacer washers 9 or 11 , annular thickening 9 or 11 of the Belleville spring central or outer support areas (respectively 12 or 10) may serve respectively as spacer elements 9 or 11. In general, depending on the context, the spacer elements 9 or 11 may represent either spacer thickenings 9 or 11 or spacer washers 9 or 11 , wherein spacer thickenings 9 or 11 are of one piece with an adjacent Belleville spring 6. For example, spacer thickenings 9 or 11 may be separate spacer elements 9 or 11 rigidly connected to the Belleville spring 6, regardless of their being clearly depicted in the drawings as separate parts, namely spacer washers 9 or 11.

The use of multiple stacked Belleville springs 6 enables reduction of the Belleville spring outer support area 10 diameter in comparison to using a single Belleville spring 6 in the nozzle valve assembly. Thereby using several smaller diameter and thinner Belleville springs 6 it is possible to make the nozzle valve assembly as a whole of significantly smaller dimensions compared to the use of a single Belleville spring 6 in the nozzle valve assembly. In the nozzle valve assemblies thus far described, the spring assembly 7 Belleville springs 6 are in their biased state.

Herein the specific Belleville spring 6 characteristic curve (drawing FIG 8) is employed, which comprises the non-linear "snap-over region".

As this graphic FIG 8 shows, in this spring characteristic region a relatively small change in pressure in the central support area 12 of the Belleville spring 6 along its axis results in a relatively large displacement of the central support area 12 of the Belleville spring 6 along said central axis. By application of such a bias to the spring assembly 7 it is possible to exploit the

"snap-over region" so that by a relatively small influence it becomes possible to switch the nozzle valve between its closed and the open positions.

This influence is accomplished by the nozzle valve assembly control means, by which said influence is realized by displacement of the valve closure element 5 in relation to its valve seat 4 by means of pressure created by a fluid medium, an electromechanical drive, a mechanical drive, a hydraulic drive, or a piezoelectric drive.

In order to compress the Belleville spring to its said bias region, the central support area 12 of the Belleville spring 6 is displaced along its axis toward the outer support area 10 of Belleville spring 6. The Belleville springs 6 of FIG 5 and 6 with corrugation 8 are depicted with their respective central support area 12 and outer support area 10 in an orientation corresponding to that of the non-corrugated Belleville spring of drawing FIG 4; i.e. in the orientation depicted in drawings FIG 4 to 6 for all of the Belleville springs 6 the central support area 12 is in the upper position, and the outer support area 10 is in the nether position.

In a preferred embodiment of the invention the Belleville spring 6 wave-shaped corrugation 8 comprises at least one peak 13, which is oriented from the outer surface of the relaxed Belleville spring 6 towards the inner surface of the Belleville spring 6.

In another preferred embodiment of the invention the Belleville spring 6 wave- shaped corrugation 8 comprises at least one peak 13, which is oriented from the inner surface of the relaxed Belleville spring 6 towards the outer surface of the Belleville spring 6 .

Preferably the transition from the wave-shaped corrugation 8 to the outer support area 10 of the Belleville spring and/or its central support area 12 occurs at a point in the wave 8 profile where in the (cf. claim 4) biased state of the Belleville spring 6 the tangent to the wave 8 profile is normal to the central axis of the Belleville spring 6.

Corrugation 8 is neccessary in order to modify the Belleville spring 6 characteristic curve FIG 8 to comply with a given application of the Belleville spring 6, achieving by the most compact means the greatest spring force in combination with the greatest elasticity of the Belleville spring 6.

The Belleville springs 6 of cross-sectional drawings FIG 4, 5, and 6 are identically oriented Belleville springs 6 of the same height, whose inner radii (central support area 12), and corresponding outer radii (outer support area 10) are practically identical in relation to the free working area. Thus it is possible to view the trapezoidal cross section of the Belleville spring 6 of drawing FIG 4 as a virtual functional schematic for the Belleville springs 6 of drawings FIG 5 and 6.

Drawing FIG 7 depicts in its compressed state an inventive Belleville spring 6 having a wave-shaped corrugation 8 consisting of two wave peaks 13, whose wave-shaped corrugation 8 is annular and symmetrical about the Belleville spring 6 central axis, wherein the two wave peaks 13 are directed respectively in opposite directions.

As can be seen from all of the preferred embodiment drawings FIG 1 , 2, 9-15, the Belleville springs 6 of the inventive nozzle valve assembly spring assembly 7 are arranged in a stack in the same orientation. Thus in the interest of compactness, they are not employed as Belleville springs 6 stacked end to end in "series stacking" (each successive pair oriented as mirror images), but rather as stacked side by side in "parallel stacking" . This is achieved by use of spacer elements 9 or 11 between the Belleville springs 6, namely by spacer washers 9 and 11. Thereby, in the case of identical Belleville springs 6, the force of each Belleville spring 6 is multiplied by the number of Belleville springs 6 in the stack.

Alignment of the Belleville springs 6 with respect to the interior of nozzle tip part 1 works by means of the peripheral edge regions 10 of the Belleville springs 6, and their associated spacer washers 11.

Due to the inventive Belleville spring's directly or indirectly aligning central support area 12 of the valve closure element 5, which includes alignment support point 16 (cf. Claim 18), being close to the valve seat 4 annular sealing surface of the poppet valve 5, wherein this close proximity, is less than the valve seat 4 sealing surface diameter, this is another unique aspect of the overall injector nozzle miniaturization in the preferred embodiments. Minimizing this proximity maximizes the stability and mechanical advantage (forces of leverage) which drives the nozzle valve self-aligning function.

Whereas the distance from central forcing surface 15 to valve seat 4 in the case of inward opening valve closure elements 5 is much less than the radial measure of the free surface remaining between the central support area 12 and the outer support area 10 covered by spacer washers 9 and 11 of the Belleville spring 6 nearest to valve closure element 5, a leverage is established which forces the valve closure element 5 into alignment with valve seat 4.

For successful dynamic application of the injector valve assembly the specific Belleville spring 6 characteristic curve (drawing FIG 8) is employed, which comprises the non-linear "snap-over region".

As this graphic shows, in this spring characteristic region a relatively small change in pressure in the central support area 12 of the Belleville spring along its axis results in a relatively large displacement (for typical automobile fuel injectors approximately 30 μm, practically insignificant) of the central part of the Belleville spring 6 along said axis. Movement of the valve closure element 5 is accomplished by the nozzle valve assembly control means, by displacement of the valve closure element 5 in relation to its valve seat 4 by means of pressure created by a fluid medium, an electromechanical drive, a mechanical drive, a hydraulic drive, or a piezoelectric drive. In all preferred embodiments the valve closure element 5 is displaced by pressure of the fluid medium, wherein the fluid medium flows through the central hole of the valve closure element 5, and through other openings in the Belleville springs 6 and openings in the body of the fuel injector tip part 1 (holes or grooves), which do not appear on the drawings, unto the annular region where the valve closure element 5 contacts its valve seat 4. Valve closure element 5 rises microscopically away from its valve seat 4 as the pressure of the fluid medium exceeds the pressure of spring assembly 7, and the flow is forced through the microscopic gap.

The embodiments of drawings FIG 1 , 2, 10-15 have complete freedom to adapt (exchange) any Belleville spring 6 corrugation 8 variant, regardless of corrugation wave 5 peak 13 number, wave peak 13 direction, or whether the corrugation 8 is present or not. Therefore PE I, PE II, PE III, PE IV, and PE V belong to category Ω.

Because in all preferred embodiments the nozzle valve spring assembly comprises more than one Belleville spring 6 in its stack, therefore PE Vl belongs to category Ω.

Because all of the preferred embodiments utilize identical springs in their stacks, PE VII io belongs to category Ω.

Whereas in all the preferred embodiments Belleville springs 6 are used in stacks requiring at least one spacer element 9 or 11 , PE VIII also belongs to category Ω.

And likewise, because in all of the preferred embodiments the Belleville springs 6 require spacer element 9 or 11 support at both of its edges, inner and outer, clearly PE IX 15 belongs to category Ω.

Because the most simple and useful spacer element 9 or 11 may be the spacer washer 9 or 11 , spacer washers are used in all of the preferred embodiments, whereby PE X also belongs to category Ω.

Because in all of the preferred embodiments it is possible to use spacer thickening 9 20 instead of spacer washers 9 in the outer support area, PE Xl also belongs in category Ω.

Whereas PE XII presents the pressure effect of alternating stacked Belleville springs 6 and spacer washers 9 or 11 holding the nozzle valve closure element 5 closed, PE XII also belongs to category Ω.

Although PE XIII is essential only in the embodiments of drawings FIG 13, 14, and 25 15, it may also be optional in the embodiment of FIG 2, and is optionally usable in all of the embodiments. Therefore PE XIII belongs in category Ω.

All preferred embodiments are optimized in order to maximize control stability and accuracy through the geometrical relationship condition of PE XIX, which therefore belongs to category Ω.

30 PE XX and PE XXI present the two most practical Belleville spring regions where the injection tip spring assembly may optionally be advantageously biased, and herefore belong to category Ω. PE XXIV is optionally useful in all embodiments, and therefore belongs to category Ω.

PE XXV, presenting the fluid medium channel 3 in the valve closure element 5 with its flow capacity and valve cooling advantages is optionally adaptable to all of the preferred embodiments, and therefore belongs to category Ω.

PE XXVI, presenting both possible valve closure element directions of movement belongs to category Ω.

The preferred means of moving the valve closure element 5 in the present invention is by controlled pressure change of the fluid medium. Therefore PE XXVII belongs in category Ω.

All preferred embodiments are independent of the type of fluid medium. Therefore PE XXVIII belongs in category Ω.

PREFERRED EMBODIMENTS CATEGORY A: PROPERTIES NOT BELONGING TO CATEGORY Ω. Preferred embodiments category A is the only category of outward opening valve nozzle valve assembly variants. Presented in drawings FIG 2, 11 , and 16, it is comprised by the working principle of claim 13.

The valve closure element 5 of this category of preferred embodiments is not self- centering in operation, but may be permanently alingned and centered with respect to its valve seat 4 axis in manufacturing production.

In the embodiments of drawings FIG 2 and 11 , at least one spacer washer 11 is aligned by the stack of Belleville springs 6 with respect to the axis of valve seat 4 with only radial freedom of movement with respect to the axis of nozzle tip part 1 , such that alignment and centering of valve closure element 5 with respect to valve seat 4 is accomplished in turn by this spacer washer 11. This embodiment is protected under claim 13.

In this embodiment, all spacer washers 11 play the same role in guiding valve closure element 5 by guiding its stem-shaped part 17, because all spacer washers 11 are firmly centered with respect to the spring assembly 7 axis by the mutual pressure of the Belleville springs 6, analogous to the working principle of a disk clutch. The spacer washers of FIG 2 have steps whose purpose is to enlarge the mutual contact surface between stem 17 and spacer washers 11 , in order to reduce wear and its consequent play. In the embodiments of drawings FIG 2, 11 , and 16 however, the spring assembly 7 comprised of Belleville springs 6 is disposed to pull valve closure element 5 against valve seat 4. In these embodiment, the valve closure element 5 and the stem-shaped part 17 of valve closure element 5 are of one piece, and the central forcing surface 15 consists of a separate element rigidly attached to the stem-shaped part 17.

In drawings FIG 2, 11 , and 16, the stem-shaped part 17 of valve closure element 5 is provided for the alignment and centering of valve closure element 5 with respect to valve seat 4, whereby the alignment of the stem-shaped part 17, and by it in turn the alignment of the valve closure element 5 is accomplished in FIG 2 and 11 by means of the central support areas 12 of the Belleville springs 6 and their spacer washers 11 , and in FIG 16 by Belleville spring outer support areas 10 and their spacer washers 9.

According to drawing FIG 2, and 11 , Belleville springs 6 are fitted to the stem-shaped part 17 with free play in order to enable the adjustment of valve closure element 5 with respect to its valve seat 4, in the case where the stem-shaped part 17 and its valve closure element 5 are rigidly joined. According to drawing FIG 16, the corresponding free play is between the Belleville spring 6 stack and its bore in nozzle tip part 1 , in which case the entire Belleville spring stack adjusts radially with the stem-shaped part 17.

Belleville spring 6 in drawing FIG 2 is disposed on the step in spacer washer 11 with play, wherein the clutch principle holds the positions of the spacer washers 11.

PE XIII, representing claim 12, belongs to category A.

PE XIV, representing claim 13, belongs to category A.

PE XXII, representing claim 21 , belongs to category A.

PREFERRED EMBODIMENTS CATEGORY B: PROPERTIES NOT BELONGING TO CATEGORY Ω. Preferred embodiments category B comprises nozzle valve assembly variants with inwardly opening valves presented in drawings FIG 9, 10, 12, and 14, under the working principle of claim 13. This preferred embodiments category presents under a single working principle an embodiment where the aligning stem-shaped part 17 is present, and other embodiments where the stem-shaped part 17 is absent. The valve closure element of drawing FIG 10 in this preferred embodiment category is not self-centering in its valve seat during operation, but is permanently alignable and centrable (adjustable) to its valve seat 4 axis in factory production. The embodiment of FIG 10 may be modified to work according to the closely similar valve centering principle of FIG 16. Drawings FIG 12 and 14 present weakly self-centering valve closure element 5 solutions, but which hold their factory adjusted centering adjustment strongly.

In the embodiments of drawings FIG 9, 10, 12, and 14, at least one spacer washer 11 is aligned by the stack of Belleville springs 6 with respect to the axis of valve seat 4 with only radial freedom of movement with respect to the axis of nozzle tip part 1 , such that alignment and centering of valve closure element 5 with respect to valve seat 4 is accomplished in turn by this spacer washer 11. This embodiment is protected under claim 13.

In the embodiments of drawings FIG 9, 10, 12, and 14, Belleville springs 6 without corrugation 8 according to drawing FIG 3 are used. Drawing FIG 9 shows spring assembly 7 of drawing FIG 10 before it is compressed between the outer forcing surface 14 and the central forcing surface 15.

In drawings FIG 9 and 10 the stem-shaped part 17 is provided for the alignment and centering of valve closure element 5 with respect to the axis of valve seat 4, whereby the alignment of the stem-shaped part 17, and by it in turn the alignment of the valve closure element 5 is accomplished by means of the central support areas 12 of the Belleville springs 6 and their spacer washers 11.

According to drawings FIG 9 and 10, Belleville springs 6 are fitted to the stem- shaped part 17 with free play in order to enable the adjustment of valve closure element 5 with respect to its valve seat 4, in the case where the stem-shaped part 17 and its valve closure element 5 are rigidly joined.

The spacer washers 11 located between the central support areas 12 of the Belleville springs 6 of embodiments displayed in drawings FIG 12 to 15 are provided on their surface with a step for the purpose of minimizing the length of the stem-shaped part 17 of the embodiments of drawings FIG 9 and 10,, and where by means of said steps the spacer washers 11 are held in place in the spring assembly between the central support areas 12 of the Belleville springs 6.

All spacer washers 11 in drawing FIG 10 are in tight contact with the stem-shaped part 17 of the valve closure element 5 which passes through them. Spacer washers 11 are in turn held tightly together with the Belleville spring 6 stack on the basis of the clutch principle precisely centered in its valve seat 4. This precise centering is permanently adjusted in the factory production of the nozzle valve assembly, which insures the accurate centering.

In the embodiments of FIG 12 and 14 is presented in two differing solutions one and the same alignment/centering principle, on the basis of claim 13, and in the case of drawing FIG 14, eliminating the stem-shaped part 17.

In drawing FIG 12 the stem-shaped part 17 is nearly eliminated, represented by a minimal-length stub of the normal stem-shaped part 17, which is held by spacer washer 11 according to claim 13 in its central position.

However, in the case of the embodiments of drawings FIG 12 and 14, a secondary, weaker alignment/centering principle operates simultaneously with the principle of claim 13, namely the principle of claim 15: The force of the Belleville springs 6, created by the outer forcing surface 14, is transmitted by means of spacer washers 11 to the central forcing surface 15 perpendicular to the minimal-length stem-shaped part 17 of valve closure element 5, resulting in valve closure element 5 being constantly aligned and centered to the axis of valve seat 4 by means of pressure and friction.

In the embodiment of FIG 14, the stem-shaped part 17 is entirely eliminated, even the stub thereof.

In the case of the embodiment of drawing FIG 14, the spacer washer 11 neccessary according to claim 13 which aligns and centers valve closure element 5 to the axis of valve seat 4 is in this case rigidly connected to, or made of one piece with a dowel, termed dowel-washer 18, whose dowel-shaped part sits tightly in the central hole of valve closure element 5, aligning it even more securely with the valve seat 4 axis than the variant of FIG

12. In addition, the pressure of the central forcing surface 15 exerts the same alignment/centering effect with respect to the axis of valve seat 4 as in the case of the variant of FIG 12.

Direct injection injector spacer washer 11 in drawing FIG 14 according to claim 13 is provided a dowel-shaped part, their combination being dowel-washer 18, which aligns and centers valve closure element 5 with respect to the axis of valve seat 4, wherein the dowel-shaped part of dowel-washer 18 may comprise a fluid medium channel 3 between spring assembly 7 and valve seat 4 (cf. claim 14; FIG 14).

PE XIII, representing claim 12, belongs to category B.

PE XIV, representing claim 13, belongs to category B.

PE XV, representing claim 14, belongs to category B.

PE XVI, representing claim 15, belongs to category B.

PE XXII, representing claim 21 , belongs to category B.

PE XXIII, representing claim 22, belongs to category B.

PREFERRED EMBODIMENTS CATEGORY C: PROPERTIES NOT BELONGING TO CATEGORY Ω. Preferred embodiments category C comprises inwardly opening nozzle valve assembly valve variants presented in drawings FIG 13 and 15, according to claim 15.

In this preferred embodiments category, the aligning stem-shaped part 17 of the valve closure element 5 is eliminated.

5 In this preferred embodiments category is presented a self-adjusting solution for the injector valve assembly. The variant presented in drawing FIG 15 ensures, by means of central step 19 of Belleville spring 6, that debris which might lodge between the valve seat 4 and the valve closure element 5 would not tip the valve closure element 5 excessively in terms of recovery time from its aligned and centered working position in valve seat 4 (cf. io Claim 16).

In drawings FIG 13 and 15 by direct or indirect pressure contact of the stack of Belleville springs 6 against the valve closure element 5, the valve closure element 5 is aligned with respect to the axis of the valve seat 4, wherein the valve closure element is allowed freedom of movement only in the radial direction relative to the axis of the 15 Belleville spring 6 stack, by which is enabled the precise alignment and centering of the valve closure element 5 with respect to its valve seat 4.

The spacer washers 11 located between the central support areas 12 of the Belleville springs 6 of embodiments displayed in drawings FIG 13 and 15 are provided on their surface with a step such that the stem-shaped part 17, is completely eliminated in 20 embodiments such as displayed in FIG 13, 14, and 15 (cf. claim 22), and where by means of said steps the assembled spacer washers 11 are held in place in the spring assembly 7 between the central support areas 12 of the Belleville springs 6.

In the embodiment of drawing FIG 13 two spacer washers, 9 and 11 , are disposed between every pair of Belleville springs 6 in sequence, whereby nozzle valve closure 25 element 5 is pressed against valve seat 4, and aligned and centered to its valve seat 4 axis by pressure against the central forcing surface 15 of valve closure element 5 by spacer washers 11 situated between the central support areas 12 of the Belleville springs 6 of the spring assembly 7.

As evident in drawing FIG 13, spacer washer 11 between two central support areas 30 12 of Belleville spring 6 is centered radially with respect to the central support area 12 of Belleville spring 6 by the step in spacer washer 11. In the given instance, the Belleville spring 6 is fitted tightly on this step (cf. claim 12).

The force of the Belleville springs 6 created by outer forcing surface 14 is transmitted by means of spacer washers 11 to the central forcing surface 15 perpendicular to the minimal-length stem-shaped part 17 of valve closure element 5, resulting in valve closure element 5 being constantly aligned and centered to valve seat 4 by means of pressure and friction.

In the case of the construction (FIG 13), valve closure element 5 is held aligned and pressed against valve seat 4 by central support area 12 of its nearest Belleville spring. The remaining stacked Belleville washers 6 express their force only through the spacer washers 11 disposed between their central support areas 12.

According to claim 15, Belleville spring 6, which directly or indirectly provides aligning contact to valve closure element 5 with respect to the axis of valve seat axis 4, is provided with an annular central step 19 by its central support area 12, by means of which valve closure element 5 is held and centered with slack for radial freedom of displacement, limiting tipping (inclination) of valve closure element 5 in its valve seat 4 (cf. claim 16).

The flange bent downward at an optional and only illustrative 45° in the Belleville spring of drawing FIG 15, namely its central step 19, is intended to limit the tipping of valve closure element 5 in its valve seat 4 in the case of debris lodging between valve closure element 5 and its valve seat 4, which would cause intolerable alignment and centering recovery time in operation if the tipping were excessive. The gap, which is observable between valve closure element 5 and the 45°downward bent central step 19 in Belleville spring 6 pressing upon it, insures axially radial freedom of self-alignment for valve closure element 5 in the embodiment of FIG 15. (cf. Claim 16)

PE XVI, representing claim 15, belongs to category C.

PE XVII, representing claim 16, belongs to category C.

PE XVIII, representing claim 17, belongs to category C.

PE XXIII, representing claim 22, belongs to category C.

PREFERRED EMBODIMENTS CATEGORY D: PROPERTIES NOT BELONGING TO CATEGORY Ω.

Preferred embodiments category D comprises the nozzle valve assembly variant presented in drawing FIG 1 , according to claim 17, which is inwardly opening. This preferred embodiments category represents the most secure and stable self-adjusting valve closure element 5 centering solution, which does not require pre-adjustment during manufacturing.

As shown In drawing FIG 1 the Belleville spring 6 stack aligns the stem-shaped part 17 separate from the valve closure element 5, which in turn aligns and centers the valve closure element 5 with respect to the axis of its valve seat 4, enabling free movement of the valve closure element 5 in the radial direction with respect to the axis of the Belleville spring assembly 7, by which the precise alignment and centering of valve closure element 5 is enabled with respect to the valve seat 4. This embodiment is protected under claim 17.

In drawing FIG 1 , the stem-shaped part 17 is provided for the alignment and centering of valve closure element 5 with respect to valve seat 4, whereby the alignment of the stem-shaped part 17, and by it in turn the alignment of the valve closure element 5 is accomplished by means of the central support areas 12 of the Belleville springs 6 and their spacer washers 11.

In the embodiment of drawing FIG 1 , valve closure element 5 and the stem-shaped part 17 of valve closure element 5 are separate parts such that pressure of the Belleville springs 6 of the spring assembly 7 against the central forcing surface 15 aligns the valve closure element 5 with respect to the valve seat 4 and the Belleville springs 6 of the spring assembly 7 urge the valve closure element 5 toward the valve seat 4 in the nozzle tip part.

The nozzle valve assembly of drawing FIG 1 uses Belleville springs 6 whose corrugation 8 direction and form correspond to the relaxed cross sectional form of Belleville spring 6 shown in drawing FIG 6 (the Belleville spring 6 of FIG 6 is shown turned 180 degrees from the Belleville spring depicted in FIG 1 ). The Belleville spring 6 pressure created by the outer forcing surface 14 is transferred by mediation of spacer washers 11 to the central forcing surface 15 perpendicular to the axis of valve closure element 5, which is the radially extending disk-shaped flat surface of stem-shaped part 17. Consequent to this, valve closure element 5 is aligned and centered with respect to the axis of valve seat 4 by the pressure and friction against said disk-shaped surface of the stem-shaped part 17. In order to minimize the possibility of valve closure element 5 tipping in its valve seat 4, the flat disk-shaped valve alignment surface of stem-shaped part 7 is made with a maximal diameter, stably supported upon an identical surface of valve closure element 5.

The invention is not limited to the preceding descriptions and illustrations of preferred embodiments, but embraces numerous other embodiment possibilities within the limits of the claims.

PE XVI, representing claim 15, belongs to category D.

PE XVIII, representing claim 17, belongs to category D.

PE XXII, representing claim 21 , belongs to category D.