WO2017138813A1

WO2017138813A1 - Rotating fuel injector assembly

Info

Publication number: WO2017138813A1
Application number: PCT/NL2017/050080
Authority: WO
Inventors: Tjeerd Sijtse Ijsselstein
Original assignee: Cereus Technology B.V.
Priority date: 2016-02-09
Filing date: 2017-02-09
Publication date: 2017-08-17

Abstract

The invention provides an assembly (100) for the injection of fuel into the combustion chamber of an internal combustion engine comprising an actuator (1) with a drive shaft (2), an engagement means (4), and a rotary fuel injector comprising a driven shaft (5), wherein the drive shaft (2) and the driven shaft (5) are axially aligned with each other, wherein the engagement means (4) comprises a rotational speed dependent locking mechanism which above a threshold value of the rotational speed automatically establishes an engagement between the drive shaft (2) and the driven shaft (5) which is required for the simultaneous rotation of these shafts.

Description

P1600035PC00

ROTATING FUEL INJECTOR ASSEMBLY FIELD OF THE INVENTION

The present invention relates to an assembly for the injection of fuel into the combustion chamber of an internal combustion engine and to a method for the injection of a fuel into such combustion chamber using a rotary fuel injector. The invention further relates to a system comprising the assembly and an internal combustion engine.

BACKGROUND OF THE INVENTION

Dutch patent NL 2001069 describes a method and device for injecting fuel into a combustion chamber through a rotating fuel injector, which results in thorough mixing between the injected fuel and the combustion air inside the combustion chamber. If executed properly, this injection method results in complete combustion of the fuel and, hence, in the prevention of the formation and the emission of particulate matter and thermal NO_x.

The described rotating fuel injector is aimed at obtaining essentially complete combustion in internal combustion engines and thereby preventing flamelet generated manifolds (FGM's). In a number of preferred embodiments it also includes an impeller to create turbulence inside the combustion chamber.

SUMMARY OF THE INVENTION

Internal combustion engines are important sources of harmful emissions such as C0₂, ΝΟχ and particulate matter (PM). A part of the emissions is inherent to the combustion of hydrocarbon fuels. However, the emission of for example PM can be prevented by ensuring complete combustion inside combustion chamber of engines. Internal combustion engines of for example power generation equipment, road vehicles, airplanes, boats and ships are important sources of harmful emissions such as C0₂, NO_x and particulate matter (PM).

The main cause of these emissions is the fact that the combustion in the combustion chambers of such engines according to the prior art is incomplete. The combustion pattern mainly consists of flamelet generated manifolds (FGM) (see further below), which is not the desired and required pattern when the formation of PM and NO_x is to be prevented. In the past few decades internal combustion engine manufacturers have been increasing the fuel injection pressure in internal combustion engines (to levels up to approximately 3000 bar), in their attempts to improve the combustion. However, the beneficial effect of such fuel injection pressure increases on the emissions have been very limited.

The known rotating, fuel injection method presents a challenge in terms of the required starting torque to set the rotatable fuel injector in motion. Furthermore, coupling of the actuator to the fuel injector and isolating the actuator from the harsh vibratory conditions of the injector are serious concerns. Although it has been demonstrated that rotational injection of fuel into a combustion chamber of an internal combustion engine is very useful, the effects of the fuel injection nozzle configuration and the rotational speed of the nozzle on the combustion process and the way to optimize the combustion through these variables were not properly understood, even not by persons skilled in the art.

Therefore, it is an object of the present invention to provide solutions for the aforementioned challenges.

Hence in a first aspect, the invention provides an assembly for the injection of fuel into a combustion chamber of an internal combustion engine comprising drive means, especially an actuator, with a drive shaft, (an) engagement means, and a rotary fuel injector ("rotary injector") comprising a driven shaft, wherein the drive shaft and the driven shaft are axially aligned with each other. The engagement means especially comprise a locking system that may enable an engagement between the drive shaft and the driven shaft which may provide a simultaneous rotation of these (coupled) shafts. The locking system especially comprises a rotational speed dependent locking mechanism and may especially (automatically) establish an (locked) engagement between the drive shaft and the driven shaft, especially above a threshold value of the rotational speed. Especially, this engagement is required for the simultaneous rotation of these (coupled) shafts.

The assembly may especially (further) comprise a control system (see further below) configured to control an element, especially one or more elements selected from the group of the engagement means, the locking system, and the actuator. Controlling an element may be mechanically based and/or software based. For instance based on comparing a (sensed) rotational speed of the actuator with a predetermined value, the engagement means may enable the engagement between the drive shaft and the driven shaft.

In a second aspect, the invention provides a system comprising the assembly of the invention and an internal combustion engine comprising a combustion chamber, wherein the rotary fuel injector is at least partly configured in the combustion chamber for injection of a fuel into the combustion chamber

In a further aspect, the invention provides a method for an injection of a fuel into a combustion chamber of an internal combustion engine comprising a rotary fuel injector, and an actuator, and especially a control system, wherein the rotary fuel injector comprises a injector nozzle hole, especially at least one injector nozzle hole, an inlet in fluid contact with the (at least one) injector nozzle hole, wherein the actuator is configured to provide a rotation to the rotary fuel injector, and especially wherein the control system is configured to control the rotation of the rotary fuel injector (as a function of a fuel exit speed); the method comprising (I)providing the fuel to the inlet of the rotary fuel injector, wherein a fuel exit speed is provided to the fuel exiting the rotary fuel injector at a location of an (the) injector nozzle hole; and (ii) actuating the actuator to provide the rotation to the rotary fuel injector and thereby proving a peripheral linear speed of the injector nozzle hole (especially wherein the rotation of the rotary fuel injector is controlled by the control system as a function of the fuel exit speed), wherein the peripheral linear speed of the (slowest moving) injector nozzle hole is selected to be at least 25% of the fuel exit speed.

Especially, the rotary fuel injector of the method comprises the rotary fuel injector of the assembly. Especially, said speed of the injector nozzle may relate to the slowest moving injector nozzle hole. A (rotary) fuel injector nozzle especially comprises a longitudinal axis (comprising a center of a cross section of the fuel injector nozzle, the cross section being perpendicular to the longitudinal axis). A center-nozzle distance of a nozzle hole may further be defined as a shortest distance between the longitudinal axis (of the injector nozzle) and the nozzle hole. Herein the term "slowest moving injector nozzle hole" especially relates to the nozzle hole having the smallest center-nozzle distance. Especially, a rotational axis of the rotary fuel injector comprises the longitudinal axis of said injector. Especially, the center-nozzle distance (of at least one nozzle hole) is larger than 0.

In yet a further aspect, the invention provides a device for the application of the method according to the invention.

The present invention provides a method and a device for operating a fuel injector of an internal combustion engine. The fuel injector essentially comprises a rotating fuel injector ("rotary fuel injector"). The (rotary) fuel injector may especially rotate about a rotational axis (of the fuel injector) with respect to (the remainder of) the internal combustion engine. For instance a rotating fuel engine may be mounted in a cylinder of an internal combustion engine and may rotate relative to the cylinder. The rotating fuel injector comprises (includes) a shaft that especially rotates concurrently with the rotating fuel injector. Especially, the rotating fuel injector including the shaft may rotate (jointly). This invention, especially provides a method and device for engaging and disengaging the power transmission from the shaft of an actuator, the "drive shaft", to the shaft of a rotatable fuel injector of an internal combustion engine, the "driven shaft". Especially, the term "an actuator" may also relate to more than one (different) actuators.

An internal combustion engine is a heat engine, a system that converts heat to mechanical energy, where the combustion of a fuel occurs with an oxidizer (usually air) in a part of the engine that is called the combustion chamber. In an internal combustion engine the expansion of the high-temperature and high-pressure gases produced by combustion apply direct force to one or more components of the engine. The force is applied typically to a component such as a piston, turbine blade, a rotor or a nozzle. This force moves the component over a distance, thus supplying useful mechanical energy.

The rotation of the rotary fuel injector may be achieved by drive means, especially by means of an actuator, in this case a rotary actuator. The actuator may comprise for example an electric motor, a hydraulic or air turbine or respective motor. In view of the usually limited space that is available around an internal combustion engine, and from a cost point of view, it is desirable to use an actuator with a low power rating and hence small dimensions, while still powerful enough to overcome the breakaway torque (or "starting torque") to set the rotatable fuel injector in motion.

In order to overcome the breakaway torque required for setting the rotatable fuel injector in motion the method according to the invention comprises starting up the actuator and letting it reach a certain rotational speed with or without a flywheel (see below) before establishing an engagement between the drive shaft and the driven shaft (see also below).

Herein, the term "drive shaft" relates to a shaft of the actuator. The "driven shaft" especially relates to a shaft of the rotary fuel injector that needs to be rotated in order to obtain rotational fuel injection. The drive shaft and the driven shaft are axially aligned with each other. Herein, axially aligned also refers to essentially axially aligned. Especially, these (axially aligned) shafts lie in extension of one another and especially their centerlines coincide. Especially a longitudinal axis of the drive shaft and a longitudinal axis of the driven shaft arranged parallel or especially may coincide. Especially, said two longitudinal axis form an angle of substantially 0°. Axially aligned may also include a (small) deviation of said angle, e.g. less than 5°

Hence, in an embodiment, the invention provides the assembly for the injection of fuel into the combustion chamber of an internal combustion engine comprising an actuator with a drive shaft, an engagement means, and a rotary fuel injector comprising a driven shaft, wherein the drive shaft and the driven shaft are axially aligned with each other, and wherein the engagement means comprise a rotational speed dependent locking mechanism which above a threshold value of the rotational speed automatically establishes an engagement between the drive shaft and the driven shaft, which especially is required for the simultaneous rotation of these shafts.

The rotational speed dependent locking mechanism (automatically) establishes an engagement between the drive shaft and the driven shaft. Especially, the engagement comprises a locked engagement. Such engagement is especially required for a simultaneous rotation of these (coupled) shafts with the same rotational speed. Especially, the rotation comprises a co-rotation as if said shafts are one single shaft.

The rotational speed dependent locking mechanism may comprise a clutch type coupling which allows some slip before establishing a locked engagement. The locking mechanism may further comprise a mechanism providing an instantaneous locked engagement. Especially, a threshold value of the rotational speed may be set (determined) before activating the locking mechanism to assure that the rotating actuator has sufficient kinetic energy to overcome the breakaway torque required to set the rotary fuel injector in motion. In embodiments, also below the threshold value engagement between the drive shaft and the driven shaft is established. Especially, the assembly, especially the locking mechanism, may be configured to establish an engagement between said shafts below, at and above said threshold value. Especially, the threshold value can be adjusted as desired.

The threshold value of the rotational speed especially relates to the rotational speed of the drive shaft. Hence, especially the drive shaft and the driven shaft may be engaged when the rotation speed of the driven shaft exceeds the threshold value. Especially, the actuator may control the rotational speed of the driven shaft. In embodiments, said shaft may engage (automatically) based on a mechanical mechanism, such as by a locking mechanism that is operated centrifugally. In embodiments, the engagement means comprise a centrifugal coupling, (see also further below).

The assembly (also) may (further) comprise a sensor for sensing (measuring) the rotational speed of the drive shaft. Alternatively or additionally a sensor may sense another parameter such as the kinetic energy of the (rotating) actuator and/or of an optional flywheel and the control system may correlate that parameter with the rotational speed of the drive shaft. Herein, a sensor may also relate to two or more (different) sensors.

Especially, the control system may control the locking mechanism based on a comparison of the sensed parameter and a (pre)determined parameter (threshold value). The control system may further control the (rotational speed of) the actuator, especially providing a determined rotational speed to the rotating fuel injector.

In embodiments, the control system may (further) control the rotation (rotational speed) of the rotating fuel injector, especially based on a determined (calculated) fuel exit speed (see further below). In embodiments, the assembly further comprises a rotational speed measuring device for measurement of the rotational speed of the shaft of the rotary fuel injector. Especially, the rotational speed measuring device 9 comprises a Hall sensor (see below). The term "controlling" and similar terms especially refer at least to determining the behavior or supervising the running of an element. Hence, herein "controlling" and similar terms may e.g. refer to imposing behavior to the element (determining the behavior or supervising the running of an element), etc., such as e.g. measuring, displaying, actuating, opening, shifting, changing temperature, etc.. Beyond that, the term "controlling" and similar terms may additionally include monitoring. Hence, the term "controlling" and similar terms may include imposing behavior on an element and also imposing behavior on an element and monitoring the element. Controlling may especially be mechanically based or software based.

The required breakaway torque to set a rotatable fuel injector of for example a

240 kW diesel engine in motion will normally be in the range of 200 to 300 Watt. Providing each of the usually 6 or 8 fuel injectors of such an engine with an actuator with a power rating of 200 to 300 Watt is relatively expensive and difficult in view of the constraints in the space that is available for mounting the actuators. In addition, since, once the fuel injector rotates at the desired speed the required power that is exerted on the driven shaft for it to retain that rotational speed will normally be in the range of only 8 to 15 Watt, it seems rather inefficient to install actuators with a power rating that is roughly a factor twenty higher.

It is, therefore, an object of this invention to provide a means of starting up the rotation of a fuel injector using an actuator with a power of for example maximum a factor two higher than the power needed for maintaining the desired rotational speed, The desired rotational power may e.g. be roughly 15 to 30 Watt in the case of the aforementioned example. The invention comprises the use of any suitable type of actuator, including but not limited to for example an electric motor, a hydraulic motor or a turbine driven by a liquid or a gas, such as for example air. The method for providing the required breakaway torque for starting up the rotation of a rotatable fuel injector of an internal combustion engine according to the invention may comprise using the kinetic energy stored in a flywheel, a mechanical device capable of storing rotational energy, connected to the rotating drive shaft of an actuator by creating an engagement between this rotating drive shaft and the still stationary shaft of the rotatable fuel injector. Especially, the flywheel may be temporarily engaged with the drive shaft to provide extra rotating energy to the drive shaft. The flywheel may be further be disengaged from the drive shaft if the energy is not required anymore (see further below). Hence in embodiments, the assembly comprises a flywheel, especially configured to engage with the drive shaft. In further embodiments, the flywheel comprises a freewheel clutch (see also below).

Furthermore, the present invention comprises an engagement assembly that allows a certain degree of axial movement of the driven shaft relative to the drive shaft while rotating and prevents or at least minimizes the axial transfer of vibrations from the fuel injector to the actuator.

In embodiments, the assembly may further comprise a second actuator (and a second engagement means) (see also further below). Especially the second actuator may be used to overcome the breakaway torque. Especially the second actuator may (also) be rotatably connected with the shaft of the rotary fuel injector. The second actuator may be of any suitable type especially with a high torque at low rotational speeds, such as for example a stepper motor, which can provide the breakaway torque required to set the rotation of the fuel injector in motion and reach a rotational speed of for example in the order of 2000 rpm. Subsequently, the second actuator can be disengaged and the first actuator may be engaged. Said two actuators of a multi actuator embodiment of the assembly according to the invention may also be integrated into one single unit. Hence, the drive means may further comprise a second actuator In embodiments, the assembly comprises a second actuator and a second engagement means, especially wherein these second engagement means are configured to effectuate a direct or indirect connection between a drive shaft of the second actuator and the driven shaft of the rotary fuel injector (as required for simultaneous rotation, especially of the drive shaft of the second actuator and the driven shaft of the rotary fuel injector). Especially the second actuator comprises a stepper motor. The second actuator may further comprise a freewheel clutch (see below). Yet in further embodiments, the second engagement means comprises a freewheel clutch. Hence, the second actuator or the second engagement means may comprise a freewheel clutch.

In a further aspect, the invention also provides a system comprising the assembly described herein and a combustion engine, especially the combustion engine described herein. Especially, the combustion engine is configured for the rotary fuel injector described herein. Especially, the system comprises a control system, at least configured to control a rotation of the rotary fuel injector, especially a rotational speed of the rotary fuel injector. The rotational speed of the fuel injector may be based on a speed of fuel exiting the fuel injector nozzle hole(s), and/or a pressure of the fuel being injected and/or a configuration of the fuel injector nozzle (see further below). Hence, the control system may control the actuator (or other drive means) (and further the engagement means) to provide the rotational speed of the rotational fuel injector. Especially, the control system may be configured to control the rotational speed of the rotational fuel injector. In embodiments, the system further comprises a sensor to measure the fuel exit speed (fuel exit speed sensor). In further embodiments, the system comprises a sensor to sense (measure) a fuel flow to the fuel injection nozzle, and the fuel exit speed is determined (calculated), especially by the control system, based on the (measured) fuel flow. Especially, the control system may be configured to control the rotation (rotational speed) of the rotational fuel injector based on the determined (or measured) fuel exit speed. The control system may determine (calculate) the fuel exit speed based on the fuel flow to the rotating fuel injector, and especially physical characteristics of the fuel injector (such as a total number of nozzle holes, a cross section of the nozzle hole opening, etc.). The rotational speed may, e.g., be controlled (by the control system) at a determined value relative to the fuel exit speed. In embodiments, the control system is configured to control the rotational speed at a value of (at least) 25% of the (measured / determined) fuel exit speed, such as at least 50%, especially at least 75% of the fuel exit speed.

The system of the invention may be used in the method of the invention. Hence, (aspects of) embodiments of the method may comprise embodiments of the system. Embodiments of the system may (also) comprise (aspects) of embodiments of the method. The system of the invention is especially configured for the method of the invention. Further, embodiments of the system may comprise (aspect) of embodiments of the device of the invention. Therefore, the system may further be explained based on (a description and embodiments of) the method of the invention and the device of the invention.

The method according to the invention for optimizing the effect of rotating fuel injection into the combustion chamber of an internal combustion engine (such as in the system of the invention) comprises controlling the rotational speed (of the rotating fuel injector) within a range that assures that the injected fuel is atomized as quickly, uniformly and efficiently as possible. The method takes advantage of the correlation between the fuel injector nozzle configuration, the fuel injection pressure and the required rotational speed for fine atomization and uniform distribution of the fuel inside the combustion chamber. In addition, the invention comprises an injection device for application of the method. The device comprises a rotatable fuel injection nozzle and especially an impeller, both with a distinguishing configuration.

Herein, a nozzle may also relate to more than one (different) nozzles. Hence a (rotary) fuel injector may comprise one or more nozzles, such as selected in the range of 1-8, especially 1-6, even more especially 1-4. Especially, the rotating fuel injector comprises at least two nozzles.

A fuel injector nozzle may further comprise more than one different nozzle holes involving. Especially, different holes may comprise a different fuel exit angles "fuel injection angles". Herein, the term "fuel injection angle" especially relates to an angle between a longitudinal axis of the fuel injector nozzle (comprising the nozzle hole) and a longitudinal axis of a bore of the nozzle hole. Especially, the longitudinal axis of the bore and the longitudinal axis of the respective nozzle (comprising said bore) form the "fuel injection angle" (of the respective nozzle opening comprising the bore). Such fuel angle may also be defined based on the longitudinal axis of the rotary fuel injector instead of the longitudinal axis of the nozzle (especially if the longitudinal axis of the rotary fuel injector may comprise the longitudinal axis of the nozzle). Herein also the phrase "the angle between a bore and the longitudinal axis of the nozzle" and the like may be used to refer to the fuel injection angle (related to the respective bore, and therefore also related to the respective nozzle comprising the bore (of the nozzle hole). Hence, the fuel injection angle especially relates to an angle relative to the longitudinal axis of the rotary fuel injector and/or the longitudinal axis of the nozzle.

The rotary injector may comprise at least two (different) fuel injection angles, such as at least three (different) fuel injection angles, especially relative to the longitudinal axis of the rotary fuel injector. In embodiments, the rotary injector comprises at least 4 (different) injection angles (relative to the longitudinal axis of the rotary fuel injector). Especially, the rotary injector comprises at least two, such as at least three, especially at least 4, (rotary fuel injector) exits, each exit comprising one respective fuel injection angle relative to the longitudinal axis of the rotary fuel injector. Especially, the rotary injector comprises a nozzle comprising at least two, such as at least three, especially at least 4, (rotary fuel injector) exits, each exit comprising one respective fuel injection angle relative to the longitudinal axis of the nozzle.

Hence, in embodiments of the method the fuel is injected into the combustion chamber under at least two different angles relative to the axis of the cylinder or relative to the rotational axis of the rotary injector.

If fuel(s) and oxidizing agents (oxygen, OH-groups, peroxides, etc.) can react with each other properly inside a combustion chamber, full combustion will occur without the release of particulate matter (PM). To achieve this with liquid fuels, the fuel will need to be transformed into the gaseous phase as complete and fast as possible. This will have to be achieved without intermediate forms which are created by phenomena such as pyrolysis.

In spite of decades of research and development work by the industry on combustion chamber geometry, injection equipment and the influence of injection pressures, there still are many problems with respect to emissions (PM, NO_x, C0₂, etc.). The recent emission scandals involving Volkswagen and other car manufacturers provide proof for that. The present invention comprises solutions that prevent or at least substantially reduce such emissions through measures at the source, instead of symptom fighting in the exhaust system through after-treatment.

Static fuel injectors according to the prior art all have the purpose of atomizing the fuel as finely as possible inside a combustion chamber, however, the performance of engines with such static injectors shows that, both in terms of fuel efficiency and emissions, the injectors apparently fail to actually achieve the intended fine atomization. Injection of fuel through static injectors according to the prior art results in massive liquid fuel jet streams inside the combustion chamber of an internal combustion engine and a combustion pattern comprising undesirable so-called flamelet generated manifolds (FGM's), which may also be referred to as separate plumes. The separated areas comprising the fuel injection jet stream and resulting plumes are referred to as FGM's, since each of them can be seen as an isolated area directly related to one of each of the nozzle holes inside the combustion chamber. Studies of these areas led to the insight that these FGM's are the cause of emissions from today's combustion engines. Apart from the intrinsic disadvantages of creating FGM's the injection techniques according to the prior art also fail to utilize the space between individual FGM's efficiently. This will be a thing of the past if the fuel is injected into the combustion chamber rotationally and under conditions as per the present invention.

Due to the high temperature of the gases around the fuel jet streams, evaporation of liquid fuel at the outer surfaces of fuel jet stream is induced and in the core of the jet stream pyrolysis of fuel takes place, which results in the formation of PM and non methane hydrocarbons ( MHC). When fuel in the jet stream which is still in the liquid phase hits relatively cold engine parts, such as the piston bowl or cylinder wall, the transition from the liquid to gaseous phase is prevented or at least slowed down. In this situation the mixing with gases is almost completely based on the heat release from the ignition phases inside the plume or FGM's. Direct reactive contact with the gases is hindered by the high velocity. The problematic mixing between liquid fuel and gases will continue to exist as long as the principle of FGM's continues to exist.

The liquid fuel that is injected through static fuel injectors constitutes only a few percent of the total volume of the combustion chamber. Emissions are created mainly in areas with a shortage of oxygen, such areas include but are not limited to:

a. positions where liquid fuel hits the cylinder wall and where heat release occurs at the cylinder wall;

b. positions where oxygen has been consumed or displaced by the reaction products of completed chemical reactions;

c. positions where oxygen is displaced due to gas transport;

Swirl and squish play a role in mitigating emissions, however they are not strong enough to prevent emissions. The spaces between FGM's (plumes) are oxygen rich areas as well as the centre around the injector nozzle. The majority of NOx is formed around the outer surface of the FGM's due to a non-uniform temperature distribution, whereby the local peak temperatures exceed the critical temperature limit for the formation of thermal NOx by far.

Static fuel injectors may have two distinct types of fuel pressure supply systems, i.e. plunger pumps or Common Rail (CR). When using a plunger pump the injection rate increases during the duration of the injection cycle as a result of the cam drive geometry. When using a plunger pump the injection rate increases if the injection duration is increased.

When using CR the injection rate decreases during the duration of the injection cycle. This is caused by a pressure drop in the rail upon opening of the injector(s). When using CR the injection rate decreases if the injection duration is increased.

An increase of the injection pressure in order to obtain a higher degree of atomization is the method applied most in the prior art. This leads to more liquid fuel hitting engine parts in the combustion chamber with the pertaining undesirable effects discussed above. In addition, higher injection pressures lead to the need for heavier fuel pump drive systems and injector components.

Using a rotating fuel injector instead of a static fuel injector for the introduction of fuel into the combustion chamber of an internal combustion engine has shown to reduce many of the aforementioned shortcomings in the combustion process. However, so far, the effects of the variables involved in rotating fuel injection on the completeness of the combustion process and hence on the emissions were not understood by persons skilled in the art.

In conceptualizing the present invention, the inventor hypothesized that the required rotational speed of a rotating fuel injector for internal combustion engines (and hence, also for the system of the invention) in order to obtain the best effect on the combustion process and to prevent FGM's, is substantially higher than the rotational speed according to the prior art. The latter is in the order of a few thousand revolutions per minute (rpm) up to approximately 6.000 rpm.

The rotation is aimed at breaking down the fuel streams that exit (each of) the injector nozzle hole(s). Immediately after the fuel is distributed further away from the nozzle hole into the combustion chamber, increased rotational speed of the injector embodiment may prevent the formation of agglomerated fuel strands, which are undesirable with respect to achieving a homogeneous distribution. Fuel strands may also lead to formation of coking, leaving combustion residues near the nozzle hole and causing PM- and MHC- emissions.

Regarding the rotational speed, the following has to be taken into account: (i) at a rotational speed that is too low the full stream will be deflected but not broken down and therefore the isolated FGM's will still be present, be it that they will show a bent shape as a result of the rotation;

(ii) at a rotational speed that is too low but higher than the speed range of (i) above, the FGM's will (partially) merge, which is not an optimal situation either;

(iii) at a rotational speed that is desirable/required no FGM's are formed and the fuel is finely dispersed, mixed and distributed uniformly with the gases across the combustion chamber.

At the fuel injection pressures of for example 1500 bar and higher that have become common nowadays the linear speed of the fuel exiting the fuel injector nozzle holes, hereinafter also called fuel exit speed, can easily exceed 100 meters per second (m/s), depending on the injector nozzle configuration and nozzle hole diameter. Especially, the linear speed of the fuel exiting the fuel injector nozzle holes relates to fuel exiting in a direction that essentially coincides with the longitudinal axis of the bore of the nozzle hole from which the fuel exits. The method for complete combustion according to the present invention involves rotating the fuel injectors at a rotational speed which results in a peripheral linear speed of a nozzle hole exit that is preferably equal to or higher than the fuel exit speed in order to prevent or minimize the occurrence of massive fuel streams and to create substantial turbulence. Especially, linear speed of a nozzle exit (such as of the slowest moving injector nozzle hole) relates to the linear peripheral speed (or peripheral linear speed) of said nozzle exit (or hole).

Herein the terms "nozzle exit", "nozzle hole" "nozzle hole exit", "nozzle opening", and "nozzle orifices" may be used interchangeably.

For example rotating fuel injection through an injection nozzle of which the nozzle hole exit openings (with a diameter of 0.22 millimeters) lie on a circle with a radius of 3.1 millimeters around the rotational axis (of the fuel injector) preferably requires a minimum rotational speed of approximately 80.000 rpm (and corresponding to a peripheral linear speed of about 26 m/s) in the case of a diesel fuel injection pressure of 600 bar and approximately 300.000 rpm (corresponding to a peripheral linear speed of about 97 m/s) if an injection pressure of 1600 bar is applied. When a rotating fuel injector is used that comprises an impeller, the rotational speeds for optimum combustion may be lower than the aforementioned levels, such as 10-90% lower, especially 25-75% lower, even more especially 40-60% lower. The invention comprises electric, pneumatic or hydraulic actuators for the rotation of the fuel injector at any rotational speed including speeds in excess of 100.000 rpm if and when required. In embodiments, the drive means, especially the actuator, is configured to provide a rotation to the injector comprising at least ten thousand rotations per minute (rpm), such as at least 25.000 rpm, especially at least 50.000 rpm, even more especially at least 100.000 rpm. Especially, the drive means are capable of effectuating a rotational speed of the injector of at least 10.000 rpm, such as 25.000 rpm, especially at least 50.000, even more especially at least 100.000 rpm. Especially, the system (or the device) is configured to provide the rotation to the injector comprising at least 10.000 (rpm), such as at least 25.000 rpm, especially at least 50.000 rpm, even more especially at least 100.000 rpm In embodiments, the driving means, especially the actuator, is configured to provide a rotation to the injector, wherein the rotation comprises a rotational speed selected to be at least 10.000 rpm and especially at maximum 500.000 rpm, such as at maximum 300.000 rpm, e.g. in the range of 20.000 - 150.000 rpm..

Apart from a minimum rotational speed of a rotating fuel injector that is required in order to obtain essentially complete combustion, the method according to the present invention may also comprise a maximum rotational speed for fuel injection into a combustion chamber. In the present context, the concept of a maximum rotational speed is counterintuitive. Once being aware of the positive effects of rotational fuel injection on the combustion process, even persons skilled in the relevant art feel that the higher the rotational speed the better the combustion will be. However, according to the present invention there may be a maximum rotational speed above which the effectiveness of the rotation may diminish or may even be reversed. For example:

a. the maximum rotational speed is reached as soon as liquid droplets reach the piston bowl and/or cylinder wall due to the fact that during the tangential transportation route (=penetration depth) the residence time is less than the time needed for evaporation of complete liquid fuel droplets. Of course, the actual evaporation speed is fuel dependent.

b. The maximum speed is reached when the centripetal acceleration forces exerted on the liquid lead to a pressure drop of zero along the nozzle exit bore. In addition to the above phenomena which may limit or even reverse the effect of rotation when the rotational speed of a fuel injector exceeds a certain maximum, there may be other reasons for not increasing the rotational speed above such a maximum. The higher the required rotational speed of a rotating fuel injector the more complex and therefore more expensive the injector will be. So, there may be no advantage in increasing the rotational speed after reaching the point at which no emissions of PM, CO and NO_x occur anymore.

The method according to the invention comprises injecting fuel rotationally into a combustion chamber whereby the rotational speed of the fuel injector is such that the peripheral linear speed of the injector nozzle opening that moves with the lowest peripheral linear speed, i.e. the injector nozzle opening(s) that is (are) the closest to the rotational axis, is at least 25% and preferably at least 100% of the fuel exit speed.

In further embodiments, said peripheral linear speed is at maximum 150% of the fuel exit speed. For a diesel fuel injector nozzle of which the nozzle hole openings (with a diameter of 0.22 millimeter each) are positioned on a circle with a radius 3.1 millimeter operating with an injection pressure of approximately 600 bar the nozzle rotational speed range according to the invention is approximately 30.000 to 120.000 rpm, relating to a peripheral linear speed in the range of approximately 10-40 m/s.

While, application of the criterion according to the invention prescribing that the rotational speed of a fuel injector should be such that the peripheral linear speed of the injector nozzle opening that moves with the lowest peripheral linear speed, i.e. the injector nozzle opening(s) that is (are) the closest to the rotational axis, is at least as high as the speed with which the injected fuel exits a fuel injector nozzle opening, will normally result in the desired homogeneous fuel air mixture and combustion conditions inside a combustion chamber, there are circumstances in which the desired combustion conditions can be achieved at a substantially lower rotational speed.

In determining a required minimum rotational speed, it may be necessary to take into account the energy state within the injector nozzle orifices (nozzle holes) versus the energy state inside the combustion chamber at the actual nozzle orifice, and to take into account that breaking-up individual fuel droplets is also influenced by the physical conditions and properties of the fuel, both in the liquid and gaseous phase. These properties include, but are not limited to: enthalpy, pressure, volume, density, temperature, shearing stress, surface roughnesses, surface tension, viscosity, ratio of liquid/gas, electric charge, etc..

Furthermore, the injection speed profile across the area of the interface, is also dependent on the geometry, for example the diameter, of the injector nozzle hole. This, in combination with the above, explains why with certain fuels and under certain conditions the desired homogeneous fuel air mixture and complete combustion can already be reached at rotational speeds of the rotating fuel injector which are as low as only approximately 25% of the minimum speed according to the above-mentioned criterion. The presence of an impeller on the rotary fuel injector promotes mixing of fuel and combustion air and may further allow a lower rotational speed to be applied.

In embodiments, application of a rotational speed that exceeded the minimum as per the above-mentioned criterion by 50% did not lead to any further improvement, on the contrary, it may lead to the undesirable effects as discussed above.

Tests which confirmed the above mentioned rotational speed criterion were performed using a commercially available electric motor supplied by Maxon Motor AG of Switzerland. A 24 Volts Maxon motor type 305013 with a nominal speed of 17.000 rpm, whereby the rotational speed range was expanded to more than 120.000 rpm by applying a voltage of up to 90 Volts, after replacement of the bearings of the motor as per instructions of the supplier.

Although the invention envisions that the rotational speed of the fuel injector can vary, for example depending on the fuel injection speed, in various embodiments of the method according to the invention the fuel injector may be rotated at an essentially constant speed. Especially at a speed that is high enough to ensure that under all operating conditions of the engine in which the injector is installed the peripheral linear speed of the slowest moving nozzle hole is at least as high as the fuel exit speed.

The method according to the invention also comprises measures which may include the positioning of objects in the fuel streams exiting the nozzle in order to initiate a breakdown or divergence of the stream as early as possible. Such measures will be beneficial for the intended refined and homogeneous distribution of fuel throughout the combustion chamber. The finer the fuel droplets that are mixed with the oxidizing agents the more complete the combustion will be. Ideally the fuel droplets should have molecular dimensions. This of course is not achievable, but nevertheless can be strived for.

The invention also includes a fuel injector of which at least two nozzle holes are positioned such that fuel exiting each of these holes exits at a different angle relative to the longitudinal axis of the cylinder. Hence, once the injector is installed in a cylinder of an internal combustion engine, fuel can be injected at different angles relative to the axis of the cylinder

BRIEF DESCRIPTION OF THE DRAWINGS

The objects and advantages of the present invention will become more apparent from the following description when taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a schematic representation of an embodiment of an assembly according to the invention;

FIG. 2 is a schematic representation of an embodiment of an assembly according to the invention;

FIG. 3 is a schematic representation of an embodiment of an assembly according to the invention with two actuators;

- FIG. 4 shows a schematic representation of an actuator with an embodiment of a pin coupling;

FIG. 5 is a schematic representation of an embodiment of an hydraulic suspension device for an actuator of an assembly according to the invention.

FIG. 6 is a schematic longitudinal section of an embodiment of a fuel injector nozzle according to the invention;

FIG. 7 is a schematic cross-section of a piston inside a cylinder of an internal combustion engine showing the effect of injecting fuel into a combustion chamber under different angles;

FIG. 8 is a schematic side view of an embodiment of an injection nozzle assembly of a rotatable fuel injector according to the invention. Identical or similar parts have been designated with identical or similar reference numbers.

DETAILED DESCRIPTION OF THE EMBODIMENTS FIG. 1 is a schematic representation of a part of an embodiment of an assembly

100 according to the invention comprising an actuator 1 with a drive shaft 2, a flywheel 3, engagement means 4 and a driven shaft 5. In selecting the flywheel 3 a compromise will have to be made with respect to the moment of inertia. In an embodiment the flywheel 3 is rigidly connected coaxially to the drive shaft 2. In an embodiment the first end, in FIG. 1 the top end, of the engagement means 4 is configured to receive and rigidly attach to the drive shaft 2 and the second end of the engagement means 4 comprises a splined or serrated hub that, when the engagement means are activated is connected rotatably to the drive shaft 2. In this embodiment the top end of the driven shaft 5 comprises a splined or serrated section which can engage with the splined or serrated hub of the engagement means 4. This provides a backlash free rotational coupling between the driven shaft 5 and the splined or serrated hub, but still allows small bidirectional axial movements of the driven shaft 5 relative to the engagement means 4. Such axial movement within the splined or serrated connection may be useful in preventing the transfer of vibratory forces from the fuel injector onto the actuator. In the embodiment discussed above the drive shaft 2 is rigidly connected to the engagement means 4 and the driven shaft is axially movable within the engagement means. It should be mentioned that the invention may include any other suitable type of engagements between respectively the drive shaft and the driven shaft and the engagement means 4.

On the one hand the moment of inertia of the flywheel 3 shall be small enough to allow a relatively low power actuator to get the flywheel rotating at the desired rotational speed as quickly as possible and on the other hand the moment of inertia shall be sufficient to overcome the breakaway torque of the rotatable fuel injector. In an embodiment of the method and assembly 100 according to the invention the engagement means 4 comprise a locking type of engagement which creates a high impact torque on the shaft of the fuel injector upon engaging. In another embodiment the engagement means provide for a more gradual engagement for example through a slipping, clutch type of power transmission. In the latter type of power transmission the impact torque obviously will be lower than in the locking type of engagement.

Since providing each rotatable fuel injector of an internal combustion engine with engagement means that have to be activated manually is impractical, various embodiments of the engagement means according to the invention comprise for example rotational speed dependent mechanisms for establishing a locking engagement between the drive shaft of an actuator and the driven shaft of a fuel injector automatically. One example of such a rotational speed dependent automatic locking mechanism comprises a mechanical locking mechanism that is operated centrifugally to provide a locking engagement between the axially-aligned drive shaft 2 and driven shaft 5. In an embodiment the engagement means 4 comprise adjustment means for setting the rotational speed threshold above which the locking engagement between the drive shaft 2 and the driven shaft 5 will be activated and remains activated until the rotational speed drops to a level below the threshold.

Instead of an automatic locking engagement and disengagement that is incorporated in the construction of the coupling, as is the case in for example a centrifugal coupling, the invention also comprises coupling means that are operated by an external signal. Examples of the latter type of couplings include, but are not limited to, liquid and magnetic couplings.

In another embodiment of the rotating fuel injector assembly according to the invention the connection between the flywheel 3 and the drive shaft 2 may disengage automatically when the rotational speed exceeds the earlier mentioned threshold rotational speed required for activating the locking engagement between the drive shaft 2 and the driven shaft 5. This may be achieved by using a so-called freewheel clutch or overrunning clutch. The disengagement of the flywheel during steady state operation of the rotating fuel injector saves energy that would otherwise be required to rotate the flywheel and may limit the amount of wear of the actuator. The engagement means to engage and disengage the flywheel may comprise a freewheel clutch which may either be installed as a separate component or may be integrated in the flywheel.

The assembly 100 according to the invention may also comprise embodiments in which the flywheel 3 and/or the engagement means 4 are integrated in the actuator 1. FIG. 1 shows an embodiment of the assembly 100 in which the flywheel 3 is positioned below the actuator. However, the invention also includes embodiments in which the flywheel is positioned on top of the actuator as schematically shown in FIG. 2. While the schematic representations in FIG. 1 and FIG. 2 show embodiments of the assembly 100 according to the invention with only one actuator, the invention also comprises embodiments of the assembly 100 with at least two actuators.

FIG. 3 is a schematic representation of an embodiment of an assembly 100 according to the invention with two actuators. The second actuator 6 may be of any suitable type with a high torque at low rotational speeds, such as for example a stepper motor, which can provide the breakaway torque required to set the rotation of the fuel injector in motion and reach a rotational speed of for example in the order of 2000 rpm. Subsequently, the second actuator 6 can be disengaged and the first actuator 1 of a type that can achieve the high rotational speeds required for the best performance of the rotating fuel injector can be engaged. The engagement means 8, also referred to as the second engagement means 8, between the shaft 7 of the second actuator 6 and the shaft 2 of the first actuator 1 may comprise for example a freewheel or overrunning clutch. As such, it is not the aim that the shaft 7 of the second actuator is connected to the drive shaft 2 of the first actuator 1, but rather, that during start-up of the rotation of the assembly 100 the shaft 7 of the second actuator is rotatably connected with the shaft 5 of the rotatable injector. This may be through the drive shaft 2 of the first actuator and/or through other intermediate components. Therefore, to reflect these options the connection between the drive shaft 7 of the second actuator 6 and the shaft 5 of the rotatable fuel injector may be referred to as a direct or indirect connection.

The actuators of a multi actuator embodiment of the assembly according to the invention may also be integrated into one single unit.

In the embodiment shown in FIG. 3 a sensor 9 for measuring the rotational speed has been installed on the driven shaft 5 of the rotatable fuel injector. Such a sensor may comprise for example a Hall effect sensor or any other suitable rotational speed measuring device of which the output signal can be fed to the on-board diagnostics (OBD) or control system of the vehicle in which the engine in question is installed. The sensor can signal to the OBD whether the fuel injector is rotating and whether it is rotating within the required rotational speed range for clean combustion. The OBD can record the rpm history of each rotatable fuel injector, thereby providing traceability and proof of operating within the required rpm range for clean combustion, and hence justification of the omission of after-treatment of the exhaust gases.

In the embodiments discussed above the direct or indirect connection of the driven shaft of the rotatable fuel injector to the drive shaft of the actuator comprised splined or serrated coupling means which allow some axial movement. However, such a splined or serrated connection cannot accommodate even a minute tilt between the two shafts. Therefore, an embodiment of the assembly 100 according to the invention comprises a pin coupling between the shaft 5 of the rotatable fuel injector and the drive shaft. FIG. 4 shows a schematic representation of an actuator with an embodiment of a pin coupling comprising two hubs and pins 14. A pin coupling allows a small axial movement of connected shafts relative to each other, a small tilt angle (between these shafts) and/or a small misalignment (of these shafts). Especially, the assembly comprises a pin coupling 13, 14 between the drive shaft 2 and driven shaft 5.

In spite of the fact that the rotating fuel injector assembly according to the present invention comprises measures to prevent or minimize the transfer of axial vibrations from the fuel injector shaft 5 to the drive shaft 2 and the actuator 1, the actuator may still be subjected to vibrations. Depending on the nature of the actuator, e.g. electric motor or hydraulic motor, vibrations may cause increased wear of the actuator to a greater or a lesser extent.

Therefore, the present invention includes measures to minimize the transfer of any type of vibration to the actuator or actuators. In an embodiment, these measures comprise an hydraulic suspension device for the actuator of an assembly according to the invention. In this context, the term suspension may also refer to any type of support system. Hence, in embodiments, the assembly 100 comprises an actuator suspension or a support means that is configured to limit vibration of one or more actuators 1,6. Especially, the actuator suspension or the support means comprise a hydraulic means (a hydraulic actuator or support means).

This suspension device dampens or smothers the vibrations to which the actuator would normally get exposed. In an embodiment of the hydraulic suspension device, the hydraulic medium of the device comprises fuel of the internal combustion engine in which the assembly is installed. This can either be an open or a closed hydraulic circuit, whereby in this context the term Open' may mean for example that the fuel passes through the suspension device before it is injected into the combustion chamber.

The fuel in the suspension device will also act as lubrication for the bearings of the actuator.

FIG. 5 shows a schematic representation of an embodiment of an hydraulic suspension device for an actuator. In this embodiment the hydraulic suspension device comprises a housing 10 which encapsulates the actuator 1 with only the actuator shaft protruding through respectively the top and bottom wall of the housing. The external diameter of the actuator 1 is smaller than the inner diameter of the housing 10. At the bottom end of its body the actuator 1 comprises a disc la, which disc has an outer diameter which is slightly smaller than the inner diameter of the housing 10, thus allowing the disc la to make small axial movements inside the housing. The annulus 11 between the actuator 1 and the housing 10 will be filled with a liquid which provides the dampening of vibrations. The disc la at the bottom end acts as a resistor for extra vibration dampening in the axial direction.

Hence, in embodiments, the hydraulic actuator suspension or support means comprise a housing 10 which encloses the actuator 1 and especially comprises a vibration dampening medium in the annulus 11 between the external surface of the actuator and the internal surface of the housing 10.

There is a virtually unlimited number of liquids that may be used as a dampening medium in the annulus 11 of the embodiment of the suspension device shown in FIG. 5. In an embodiment the annulus 11 is filled with a thixotropic fluid which provides effective vibration dampening in all directions. The viscosity can be adapted to the motor vibrations and the motor mass that needs to be dampened. Especially, the vibration dampening medium comprises a thixotropic fuel, In further embodiments, the vibration dampening medium comprises fuel.

Of course, vibration dampening for the motor of the assembly according to the invention is not necessarily confined to only the use of a liquid medium, but may also comprise active suspension in combination with dampening through a liquid medium.

FIG. 6 is a schematic longitudinal section of an embodiment of a fuel injector nozzle 21 according to the invention. In this view six sectioned nozzle holes involving in total essentially three different fuel exit angles, also referred to as fuel injection angles, are shown. In this embodiment the bores of each pair of opposite nozzle holes are positioned at an essentially equal angle relative to the longitudinal axis of the nozzle. Another embodiment of the fuel injector nozzle according to the invention comprises an eight hole nozzle in which each of the eight bores of the nozzle holes is placed at a different angle relative to the axis of the nozzle. Of course, the invention also comprises yet other embodiments of the nozzle with less than six or more than eight holes and with a different configuration of the bores and angles.

Even when used as a static injector a rotary fuel injector with a plurality of nozzle injection angles is likely to provide improved fuel and air mixing and improved combustion. A fuel injector with a plurality, i.e. two or more, of nozzle injection angles, may hereinafter also be referred to as multi injection angle nozzle.

Since certain embodiments of the rotary fuel injector that may be used in applying the method according to the invention are redundant, meaning for example that if the rotation would cease the fuel injector can still continue to operate as a static fuel injector, the term rotating or rotary fuel injector used in this description and the claims below, shall be construed to include static fuel injection with respect to the nozzle injection angles.

FIG. 7 is a schematic cross-section of an example of a piston 23 inside a cylinder 24 of an internal combustion engine, whereby fuel is injected into the cylinder through a multi injection angle nozzle 21. In the drawing of FIG. 7 the piston is essentially in the top dead center (TDC) position. In moving towards the TDC the gasses are displaced to the piston bowl and are transported towards the center. The latter is also referred to as squish. When the piston moves downwards the reverse takes place. In both cases these gas streams intersect with the fuel injected through the rotating multi injection angle nozzle according to the invention. Due to the different angles the injected fuel follows a number (depending on the number of different injection angles) of different cone shaped patterns, which may be beneficial in limiting the required nozzle rotational speed for a maximum effect on increasing the completeness of the combustion process. FIG. 7 does not show the fuel injector's impeller as used in many embodiments of the fuel injector according to the invention. The impeller may help in creating turbulence and close contacts between the fuel and oxidizing agents. FIG. 8 is a schematic side view of an embodiment of (the system and) of an injection nozzle assembly of a rotatable fuel injector according to the invention. In this embodiment the injection nozzle assembly comprises a nozzle 21 and a cone shaped object 25, hereinafter also called cone 25, that is placed in front of the nozzle hole coaxially with the bore of the nozzle hole and whereby the vertex of the cone is facing the nozzle hole. A distance from the vertex of the cone to the face of the nozzle hole may be selected to be anywhere from zero to a few millimeters, as desired. Especially, said distance is selected in the range of 0-1 mm. Especially, (the vertex of) the cone may not contact the nozzle hole. The distance between the vertex of the cone and the nozzle hole may be a shortest between the cone and the nozzle hole. Fuel exiting the nozzle hole will hit the cone and will be diverged to also adopt a cone like flow pattern as shown schematically by the lines 26, of which only one has been numbered. Since the fuel stream is spread and assumes an essentially hollow cone like pattern, it will subsequently be broken down more quickly and efficiently due the rotation of the nozzle assembly than is the case with a massive fuel stream. Instead of a cone shaped object 25, hereinafter also referred to as a flow diverging object 25, the invention also comprises embodiments of the nozzle assembly with other shapes of flow diverging objects, such as for example a pyramid shape. The flow diverging object is especially configured to diverge a fuel exiting the rotary fuel injector. The flow diverging objects can be attached to the nozzle of a rotating fuel injection device according to the invention in any practicable manner, such as for example integration in an impeller that may be mounted on the nozzle. Hence, the system may further comprise a flow diverging object, especially a cone. The flow diverging object may further comprise a pyramid. Especially the flow diverging device is arranged (positioned) (at a location) in front of the exit opening (especially adjacent to the exit opening) of a nozzle hole essentially coaxially with the bore of the nozzle hole, especially wherein a vertex of the diverging object, especially the tip (of the diverging object) extends towards the nozzle hole. Especially, the system of the invention comprises a flow diverging object, configured to diverge a fuel exiting the rotary fuel injector.

In an embodiment of the fuel injection device according to the invention the flow diverging object 25 is also used as an electrode in order to electrostatically influence the fuel and/or the fluid that is injected. Electrostatic influence may help in accelerating the release of free radicals. Especially, the flow diverging object comprises an electrode

In an embodiment, the impeller of the injection device is then used as an electrode with an opposite charge relative to the charge of the flow diverging object. By transferring this opposite charge to the gases, the reaction between the fuel/fluid and the gases is promoted.

In yet another embodiment of the fuel injection device the nozzle is static but the fuel exiting the nozzle hits an object that rotates in front of the nozzle exit end of the injector and the fuel stream will be broken down by this collision with the rotating object and, hence, will be distributed across a substantial part of the combustion chamber. Such a rotating object may comprise an impeller, a crown with blades of any shape and size which is beneficial in breaking down the fuel or fluid stream.

Hence, the present invention relates to a rotating fuel injector assembly for internal combustion engines. More in particular it relates to the support of the actuator that drives the rotation of the fuel injector, to the nature of the actuator, to methods of leveraging the power of the actuator in order to overcome the breakaway torque of the rotatable fuel injector and to the coupling between the actuator and the rotatable fuel injector. The present invention further relates to a method and a device for fuel injection into the combustion chamber of internal combustion engines aimed at increasing the fuel efficiency of and reducing the emissions by such engines.

As described above, the invention may be especially be embodied in the following embodiments, wherein the embodiments are merely numbered for reference reasons.

1. An assembly for the injection of fuel into the combustion chamber of an internal combustion engine comprising an actuator (1) with a drive shaft (2), engagement means (4) and a rotary fuel injector comprising a driven shaft (5), whereby the drive shaft (2) and the driven shaft (5) are essentially axially aligned with each other, wherein the engagement means (4) comprise a rotational speed dependent locking mechanism which above a threshold value of the rotational speed automatically establishes an engagement between the drive shaft (2) and the driven shaft (5) which is required for the simultaneous rotation of these shafts. 2. Assembly according to embodiment 1, wherein the threshold value can be adjusted as desired.

3. Assembly according to embodiment 1 or 2, wherein the engagement means (4) comprise a centrifugal coupling.

4. Assembly according to any of the embodiments 1-3, characterized in that the assembly comprises a second actuator (6) and second engagement means (8) whereby these second engagement means may effectuate a direct or indirect connection between the drive shaft (7) of the second actuator (6) and the driven shaft (5) of the rotary fuel injector as required for simultaneous rotation.

5. Assembly according to embodiment 4, wherein the second actuator (6) comprises a stepper motor.

6. Assembly according to embodiment 5, wherein the second actuator (6) or the second engagement means (8) comprise a freewheel clutch.

7. Assembly according to any of the preceding claims, wherein the assembly comprises a flywheel (3).

8. Assembly according to embodiment 7, wherein the flywheel (3) comprises a freewheel clutch.

9. Assembly according to any of the embodiments 1-8, wherein the assembly comprises actuator suspension or support means that limit the vibration of the actuators. 10. Assembly according to embodiment 9, wherein the actuator suspension or support means comprise hydraulic means.

11. Assembly according to embodiment 9 or 10, wherein the hydraulic actuator suspension or support means comprise a housing (10) which encloses the actuator and comprises a vibration dampening medium in the annulus (11) between the external surface of the actuator and the internal surface of the housing (10).

12. Assembly according to embodiment 11, wherein the vibration dampening medium comprises fuel.

13. Assembly according to embodiment 11, wherein the vibration dampening medium comprises a thixotropic fluid.

14. Assembly according to any of the embodiments 1-13, wherein the assembly comprises a pin coupling (13,14). 15. Assembly according to any of the embodiments 1-14, wherein the assembly comprises a rotational speed measuring device (9) for measurement of the rotational speed of the shaft (5) of the rotary fuel injector.

16. Assembly according to embodiment 15, wherein the rotational speed measuring device (9) comprises a Hall sensor.

17. A method for the injection of a fuel into a combustion chamber of an internal combustion engine using a rotary fuel injector, wherein the rotational speed of the rotary injector is selected such that the linear speed of the slowest moving injector nozzle hole of the rotary injector comprises at least twenty five and at the most one hundred and fifty percent of the fuel exit speed.

18. Method according to embodiment 17, wherein the rotational speed is selected such that the linear speed of the slowest moving injector nozzle hole of the rotary injector comprises at least fifty and at the most one hundred and twenty five percent of the fuel exit speed.

19. Method according to embodiment 17 or 18, wherein the rotational speed is selected such that the linear speed of the slowest moving injector nozzle hole of the rotary injector comprises at least seventy five and at the most one hundred and ten percent of the fuel exit speed.

20. Method according to any of the embodiments 1-19, wherein the fuel is injected into the combustion chamber under at least two different angles relative to the axis of the cylinder or relative to the rotational axis of the rotary injector.

21. A device for the application of the method according to any of the embodiments 17-20.

22. Device according to embodiment 21, wherein the device comprises a rotary injector comprising at least two different fuel injection angles.

23. Device according to embodiment 21 or 22, wherein the device comprises a rotary injector comprising at least three different fuel injection angles.

24. Device according to any of the embodiments 21-23, wherein the device comprises a rotary injector comprising at least four different fuel injection angles.

25. Device according to any of the embodiments 21-24, wherein the device comprises drive means capable of effectuating a rotational speed of the injector of at least ten thousand rotations per minute. 26. Device according to any of the embodiments 21-25, wherein the device comprises drive means capable of effectuating a rotational speed of the injector of at least twenty five thousand rotations per minute.

27. Device according to any of the embodiments 21-26, wherein the device comprises drive means capable of effectuating a rotational speed of the injector of at least fifty thousand rotations per minute.

28. Device according to any of the embodiments 21-27, wherein the device comprises drive means capable of effectuating a rotational speed of the injector of at least one hundred thousand rotations per minute.

29. Device according to any of the embodiments 21-28, wherein the device comprises a flow diverging object (25).

30. Device according to embodiment 29, wherein the flow diverging object comprises a cone or a pyramid.

31. Device according to embodiment 30, wherein the cone or the pyramid are positioned in front of the exit opening of a nozzle hole essentially coaxially with the bore of the nozzle hole with the tip pointing towards the nozzle hole.

32. Device according to any of the embodiments 29-31, wherein the flow diverging object (25) comprises an electrode. Especially, the device comprises the actuator, (or drive means), the engagement means, and especially the flywheel.

Especially the assembly according to the invention comprises the device according to the invention and the rotary fuel injector.

Many changes can be made in the method and device described above without departing from the intent and scope thereof. It is intended therefore that the above description and accompanying drawings be interpreted as illustrative and not in a limiting sense.

The priority documents are incorporated herein.

Claims

1. An assembly (100) for the injection of fuel into the combustion chamber of an

internal combustion engine comprising an actuator (1) with a drive shaft (2), an engagement means (4), and a rotary fuel injector comprising a driven shaft (5), wherein the drive shaft (2) and the driven shaft (5) are axially aligned with each other, wherein the engagement means (4) comprises a rotational speed dependent locking mechanism which above a threshold value of the rotational speed automatically establishes an engagement between the drive shaft (2) and the driven shaft (5) which is required for the simultaneous rotation of these shafts.

2. Assembly (100) according to claim 1, wherein the threshold value can be adjusted as desired.

3. Assembly (100) according to claim 1 or 2, wherein the engagement means (4) comprises a centrifugal coupling.

4. Assembly (100) according to any of the preceding claims, characterized in that the assembly (100) comprises a second actuator (6) and second engagement means (8) wherein these second engagement are configured to effectuate a direct or indirect connection between a drive shaft (7) of the second actuator (6) and the driven shaft (5) of the rotary fuel injector as required for simultaneous rotation of the drive shaft (7) and the driven shaft (5).

5. Assembly (100) according to claim 4, wherein the second actuator (6) comprises a stepper motor.

6. Assembly (100) according to claim 5, wherein the second actuator (6) or the second engagement means (8) comprise a freewheel clutch.

7. Assembly (100) according to any of the preceding claims, wherein the assembly (100) comprises a flywheel (3) configured to engage the drive shaft (2).

8. Assembly (100) according to claim 7, wherein the flywheel (3) comprises a

freewheel clutch.

9. Assembly (100) according to any of the preceding claims, wherein the assembly (100) comprises an actuator suspension or a support means, configured to limit vibration of one or more of the actuators (1,6).

10. Assembly (100) according to claim 9, wherein the actuator suspension or the support means comprises a hydraulic means.

11. Assembly (100) according to claim 10, wherein the hydraulic actuator suspension or the support means comprises a housing (10) which encloses the actuator (1) and comprises a vibration dampening medium in the annulus (11) between the external surface of the actuator (1) and the internal surface of the housing (10).

12. Assembly (100) according to claim 11, wherein the vibration dampening medium comprises fuel.

13. Assembly (100) according to claim 11 or claim 12, wherein the vibration dampening medium comprises a thixotropic fluid.

14. Assembly (100) according to any of the preceding claims, wherein the assembly comprises a pin coupling (13, 14) between the drive shaft (2) and the driven shaft (5).

15. Assembly (100) according to any of the preceding claims, wherein the assembly comprises a rotational speed measuring device (9) for measurement of the rotational speed of the shaft (5) of the rotary fuel injector.

16. Assembly according to claim 15, wherein the rotational speed measuring device (9) comprises a Hall sensor.

17. System comprising the assembly (100) according to any of the preceding claims and an internal combustion engine comprising a combustion chamber, wherein the rotary fuel injector (1) is at least partly configured in the combustion chamber for injection of a fuel into the combustion chamber.

18. System according to claim 17, further comprising a control system, wherein the control system is configured to control a rotation of the rotatory fuel injector (1).

19. System according to claim 17 or 18, wherein the system comprises a rotary fuel injector (l)comprising at least two different fuel injection angles relative to a longitudinal axis of the rotary fuel injector.

20. System according to claim 17-19, wherein the system comprises a rotary fuel

injector (1) comprising at least three different fuel injection angles relative to a longitudinal axis of the rotary fuel injector.

21. System according to any of the claims 17-20, wherein the system comprises a rotary fuel injector (1) comprising at least four different fuel injection angles relative to a longitudinal axis of the rotary fuel injector.

22. System according to any of the claims 17-21, wherein the system is configured to provide a rotation to the rotary fuel injector (1) comprising at least ten thousand rotations per minute.

23. System according to any of the claims 17-22, wherein the system is configured to provide a rotation to the rotary fuel injector (1) comprising at least twenty five thousand rotations per minute.

24. System according to any of the claims 17-23, wherein the system is configured to provide a rotation to the rotary fuel injector (1) comprising at least fifty thousand rotations per minute.

25. System according to any of the claims 17-24, wherein the system is configured to provide a rotation to the rotary fuel injector (1) comprising at least one hundred thousand rotations per minute.

26. System according to any of the claims 17-25, wherein the system comprises a flow diverging object (25), configured to diverge a fuel exiting the rotary fuel injector.

27. System according to claim 26, wherein the flow diverging object comprises a cone or a pyramid.

28. System according to claim 27, wherein the cone or the pyramid are positioned in front of the exit opening of a nozzle hole essentially coaxially with the bore of the nozzle hole with the tip pointing towards the nozzle hole.

29. System according to any of the claims 26-28, wherein the flow diverging object (25) comprises an electrode.

30. A method for an injection of a fuel into a combustion chamber of an internal

combustion engine comprising a rotary fuel injector, and an actuator, wherein the rotary fuel injector comprises at least one injector nozzle hole, an inlet in fluid contact with the at least one injector nozzle hole, wherein the actuator is configured to provide a rotation to the rotary fuel injector; the method comprising:

(i) providing the fuel to the inlet of the rotary fuel injector, wherein a fuel exit speed is provided to the fuel exiting the injector at a location of an injector nozzle hole; and (ii) actuating the actuator to provide the rotation to the rotary fuel injector and thereby providing a peripheral linear speed of the injector nozzle hole;

wherein the peripheral linear speed of the slowest moving injector nozzle hole is selected to be at least 25% of the fuel exit speed.

31. The method according to claim 30, wherein the assembly according to any one of the preceding claims 1-16 or the system according to any one of claims 17-29 is applied.