Patent Grant
9897060
This application claims priority to German Patent Application No. 102015219515.5, filed Oct. 8, 2015, the entire contents of which are hereby incorporated by reference for all purposes.
The present description relates generally to methods and systems for a fuel injector arrangement for an internal combustion engine.
Injectors or injection nozzles form significant components of an internal combustion engine. The injectors are used to inject fuel into respective cylinders before a fuel/air mixture is ignited by compression. Each injector is at least in most cases arranged in a respective recess provided in a cylinder head of the engine. Each injector includes a valve, which is opened for injection. This can be accomplished, on the one hand, by means of a pressure pulse produced by a pump associated with the individual injector. On the other hand, it is also possible for the valve to be controlled electromagnetically, wherein all of the injectors are supplied by a common pressure reservoir. Depending on the design of the engine, injection is performed directly into the combustion chamber (direct injection), wherein the piston top often has an annular recess, or alternatively into a swirl chamber of a split combustion chamber (chamber-type engine).
In addition to the geometry of the injector, in particular the number, shape, size and alignment of openings via which the actual injection process takes place, the combustion process is decisively influenced by an amount of “nozzle tip protrusion”. This is a measure of how far a forwardmost part of the injector, the nozzle tip, projects into the cylinder. However, different amounts of tip protrusion would be regarded as the optimum, depending on the cycle and the associated different operating points. This is due, on the one hand, to different requirements of the injection and combustion process (e.g. partial load or full load) and, on the other hand, to the fact that a large tip protrusion entails increased thermal stress on the nozzle tip at full load, reducing the life thereof, whereas this is a fairly minor problem at partial load.
The efficiency of the combustion process is determined by optimum mixture preparation, which, on the one hand, is achieved in terms of air involved by means of appropriate inlet ports and piston recess geometries and, on the other hand, in terms of the fuel involved by means of optimum introduction of the fuel through appropriate injection nozzle configuration. It should be noted here that the penetration depth (nozzle tip protrusion) of the injection nozzle is set in an optimum manner in accordance with the operating point. Low-load operating points at a relatively low engine speed, generally with a late injection event and a low injection pressure, require larger amounts of tip protrusion to achieve an optimum jet pattern in the combustion recess. With increasing load and engine speed and corresponding advance of the main injection event and increasing injection pressure, smaller amounts of nozzle tip protrusion are required to achieve a corresponding recess jet pattern. Injection jets outside the recess should be avoided for reasons connected with emissions (high HC, CO, soot figures).
In practice, the nozzle tip protrusion is chosen in such a way that it corresponds to a compromise. The nozzle tip protrusion is often adjusted by means of a rigid washer placed between the injector and the cylinder head, wherein a shoulder of the injector is supported on the washer, which, for its part, is supported on the cylinder head.
DE 40 22 299 C2 shows a height-adjustable washer having two washer parts lying one above the other and having contact surfaces which are embodied as rising helical surfaces, each having a ramp. In this case, at least two concentric helical surfaces are formed on each washer part, the ramps of said surfaces being offset relative to one another by a certain angle in the circumferential direction. The height of the washer was adjusted by twisting the washer parts relative to one another, wherein improved tilt stability of the washer parts relative to one another is achieved by means of the mutually offset ramps.
U.S. Pat. No. 7,703,727 B2 discloses an adjustable spacer arrangement having two wedge elements resting one upon the other, which are connected by at least one adjustable connecting arrangement. The latter is connected to the two wedge elements so as to be pivotable in all cases and engages with said elements via connecting elements, the spacing of which relative to one another can be varied. Varying the spacing has the effect that the wedge elements move relative to one another along their contact surface, thereby changing the overall height of the arrangement. According to one embodiment, the spacing can be varied by means of a hydraulic cylinder.
CN 202114508 U shows a height-adjustable supporting unit. This comprises a base, an adjusting block and a nut. The adjusting block and the nut are provided with internal threads and are screwed onto an external thread on a shaft of the base. The overall height of the unit can be varied by screwing and unscrewing.
In view of the prior art indicated, there is still room for improvement in the provision of an injector which is optimized as regards the injection process, especially in respect of the nozzle tip protrusion.
It is the underlying object of the present disclosure to optimize the injection process of an injector in an internal combustion engine, e.g. a diesel engine.
According to the present disclosure, the object is achieved by an injector arrangement for an internal combustion engine, comprising: an injector at least partially arranged in a cylinder head; a nozzle tip coupled to the injector and arranged at an end of the injector in an axial direction; and an actuator configured to vary a position of the nozzle tip relative to the cylinder head in the axial direction, with a minimum position and a maximum position of the nozzle tip set by the actuator.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.
In the various figures, parts that are equivalent in terms of their functioning are always provided with the same reference signs, and they are therefore also generally described only once.
The present disclosure makes available an injector arrangement for an internal combustion engine, e.g. a diesel engine. In particular, this can be a diesel engine for a motor vehicle such as a heavy goods vehicle or passenger vehicle. Of course, the internal combustion engine can also be a spark ignition engine. The term “arrangement” normally means that this comprises a plurality of parts, although these may be connected permanently to one another. The injector arrangement has an injector for at least partial arrangement in a cylinder head of the internal combustion engine, e.g. the diesel engine. That is to say, the injector is mounted in a correspondingly designed recess in the cylinder head. Parts of the injector can project from the cylinder head on a side facing the cylinder and/or a side facing away from the cylinder. Of course, the injector, which can also be referred to as an injection nozzle, is used for injecting fuel into a cylinder of the internal combustion engine, e.g. the diesel engine, i.e. it has a connection for a fuel line and a valve, by means of which the injection process can be controlled. As regards the type of injection control, there are fundamentally no restrictions in the context of the present disclosure. That is to say, the valve can be opened by means of a pressure pulse from a pump associated with the injector, for example, or alternatively electromagnetically.
The injector has a nozzle tip arranged at the end in an axial direction. This nozzle tip forms, as it were, the end of the injector which is oriented toward the cylinder in the installed state and may also project into said cylinder. The term “axial direction” should not be interpreted to mean that the injector or parts thereof necessarily exhibit (axial) symmetry with respect to this direction, even if this can apply to parts of the injector. Of course, the axial direction points toward the cylinder in the installed state. Of course, the injector can be arranged with its axis oblique to the cylinder axis, this being possible in the case of a multi-valve concept, i.e. with a two-valve concept for example, wherein the axial direction in the sense according to the present disclosure points toward the cylinder in the installed state in this embodiment too. The nozzle tip has openings through which the fuel is introduced, that is to say injected for example, from the injector into the cylinder.
According to the present disclosure, the injector arrangement has an actuator, by means of which a position of the nozzle tip relative to the cylinder head can be varied in the axial direction. By means of said actuator, the nozzle tip protrusion can be varied in the installed state since the cylinder head and the cylinder are installed so as to be stationary relative to one another. It is thus possible to adapt the protrusion by means of the actuator, depending on the instantaneous requirements. Thus, at full load, for example, a shorter nozzle tip protrusion can be set than at partial load. In this case, the changes can be made, as it were, dynamically during the operation of the internal combustion engine, e.g. the diesel engine. Depending on the type and speed of the actuator, it is also possible to vary the position of the nozzle tip within a cylinder cycle.
The efficiency of the combustion process is determined by optimum mixture preparation, which, on the one hand, is achieved in terms of the air involved by means of appropriate inlet ports and piston recess geometries and, on the other hand, in terms of the fuel involved by means of optimum introduction of the fuel through appropriate injection nozzle configuration. By means of the present disclosure, the penetration depth (nozzle tip protrusion) of the injection nozzle is adjusted continuously to allow optimum adaptation in accordance with the operating point. Thus, by means of the present disclosure, longer or shorter nozzle tip protrusions can be set, depending on the operating load, in order to achieve an optimum jet pattern in the combustion recess, wherein injection jets outside the recess (high HC, CO, soot figures) are also avoided.
The variability of the position of the nozzle tip explicitly includes the possibility that the position of other parts of the injector and, in particular, the position of the injector overall, can be varied. It is self-evident that the actuator can be controlled in a suitable manner by means of the engine control system. As regards the functioning of the actuator, there are fundamentally no restrictions, even if a number of preferred embodiments are discussed below. The actuator can be connected in a fixed manner to the injector and may even be integrated into the latter. As an alternative, however, it can also form a separate component resting on the injector, for example. There is also the possibility that the injector arrangement will have a plurality of actuators, even if a single actuator is sufficient.
Since it is desirable that it should be possible to set the position of the nozzle tip in a predetermined manner, it is possible according to the present disclosure optionally for a predetermined minimum position and a predetermined maximum position of the nozzle tip to be set by means of the actuator. The minimum and maximum positions represent the outermost positions of the movement of the nozzle tip. The nozzle tip can adopt at least these two positions in a defined manner, and it can be held in these positions. Of course, one of the positions corresponds to a minimum nozzle tip protrusion and the other corresponds to a maximum nozzle tip protrusion. Thus, for example, the minimum position can be provided for full load and the maximum position for partial load or vice versa.
Even if an improvement over the prior art can already be achieved through the possibility of setting two extreme positions, it is advantageous if at least one intermediate position between the minimum position and the maximum position can be set by means of the actuator. Finer matching of the nozzle tip protrusion is thereby possible, thereby allowing the combustion process to be made even more efficient. In particular, there is the possibility that a plurality of intermediate positions or even any desired intermediate position can be set. For the last mentioned case, in which therefore there is continuous adjustability, a multiplicity of different actuators is suitable (but not a stepper motor, for example).
As already explained, the change in position can affect just one part of the injector comprising the nozzle tip. It would thus be conceivable for some other part of the injector to remain stationary and for the injector, as it were, to expand or contract.
According to a preferred embodiment, the change in position affects the entire injector. It is preferred here that the injector arrangement comprise a spacer element for arrangement between the injector and the cylinder head, wherein an axial extent of the spacer element is adjustable by means of the actuator. Said spacer element can optionally be connected detachably or non-detachably to the injector, or it can be of separate construction and merely rest on the injector. Normally, the spacer element is arranged between the injector and the cylinder head in the axial direction. In each case, the change in the axial extent of the spacer element has the effect that the axial position of the injector relative to the cylinder head changes. The spacer element can consist of a single component or of a plurality of components. In principle, it is also conceivable for a plurality of spacer elements to be provided. According to one embodiment, shoulders extending at an angle to the axial direction and supported on one another with the spacer element in between are formed both on the injector and on the cylinder head.
To prevent tilting of the injector when the latter is moved by the spacer element, it is advantageous if the action of the force exerted by the spacer element is not one-sided but is more or less symmetrical. According to an advantageous embodiment, this is promoted by the fact that the spacer element is arranged tangentially around the injector. Here, the term “tangentially” should, of course, be understood in relation to the abovementioned axial direction. The spacer element can be arranged so that it surrounds the injector completely or partially, wherein it preferably occupies an angle of at least 180° around the injector. In particular, the spacer element can have a cross section in the form of a circular ring or a circular arc in this case. In principle, however, the cross section can also be oval or polygonal, for example. Particularly in cases in which the spacer element is arranged so as to extend all the way around, the injector can also be said to be passed through the spacer element. Formed within the spacer element is an aperture which corresponds at least to the outside dimensions of the injector. In this case, the injector can have a tapered region, which merges via a shoulder into a wider region, wherein the spacer element rests on the shoulder and completely or partially surrounds the tapered region.
The spacer element can optionally be embodied in a space-saving manner. According to one embodiment, the spacer element is flattened in the axial direction. This should be understood to mean that a dimension of the spacer element in the axial direction is smaller than the minimum dimension transversely to the axial direction. This configuration can be combined especially with the abovementioned encircling arrangement of the spacer element. In the case of a spacer element in the form of a circular ring, for example, the thickness thereof (in the axial direction) is less than the outside diameter thereof. Furthermore, the thickness can be less than the internal radius or, in general terms: it can be less than 50% of the minimum dimension transversely to the axial direction. The spacer element preferably extends in a plane transverse to the axial direction. In particular, it can have approximately the shape of a washer.
Although it is conceivable in principle that the spacer element and the actuator form components that are completely separate from one another, it is preferred if the spacer element at least partially comprises the actuator. That is to say at least part of the actuator is integrated into the spacer element, or it is even conceivable for there to be no physical separation between the actuator and the spacer element, i.e. the actuator (or optionally a part thereof) is formed by the spacer element, or the actuator forms the spacer element.
As regards the functioning of the actuator used, there are in principle no restrictions. Overall, preference is given to actuators by means of which it is possible to achieve a rapid response time. In particular, the response time should be significantly shorter than one cycle of the internal combustion engine (e.g., cylinder cycle), that is to say, for example, of the diesel engine, to enable the nozzle tip protrusion to be adapted during one cycle. It is preferred if the injector adjustment has a resolution on the cycle level, i.e. can be carried out within the millisecond range. The actuator can be designed as an electroactive polymer actuator (EAP actuator) or as an electric motor. In the latter case, it can be a linear motor, in particular. The electric motor can optionally also be designed as a stepper motor.
According to a preferred embodiment, the actuator is a piezoelectric actuator, i.e. a piezoelectric element. This can advantageously be combined with the embodiment in which a spacer element designed as a washer is provided. With such an actuator, it is possible to vary the axial extent of the spacer element in a particularly simple manner without the need for the actuator to comprise moving parts. The application of an electric voltage across a piezoelectric element has the effect that its extent changes, i.e. the piezoelectric element contracts or expands. It can be a multilayer piezoelectric element, for example, by means of which a greater expansion can be achieved for the same voltage. The response time of a piezoelectric actuator is sufficiently short to perform a plurality of adjustments during one cycle of the internal combustion engine, i.e. the diesel engine, for example. By means of an actuator of this kind, it is, of course, possible, through the choice of voltage, to vary the position of the nozzle tip or of the injector continuously, meaning that the nozzle tip protrusion can be varied continuously.
It is furthermore preferred here that the piezoelectric actuator be formed by the spacer element. That is to say that, in this case, there is absolutely no physical separation between the actuator and the spacer element; instead, a single component performs both functions. In this case, therefore, the piezoelectric actuator is arranged as a spacer element between the injector and the cylinder head, and the position of the injector is varied by varying the axial extent of said element, which can be adjusted by means of a power supply. In this case, the piezoelectric actuator can be in the form of a circular ring and have approximately the shape and dimensions of a washer, as already mentioned above. That is to say that, apart from the fact that supply leads for supplying power to the actuator must be provided, this embodiment can be integrated into existing systems particularly easily and without major adaptations. The actuator as it were exerts a pressure but no tension, and therefore the injector is actively raised but not lowered. Thus, in a preferred embodiment, a fastening device in the illustrative embodiment is provided as a “clamp”, which is used for injector installation in the injector bore. One side of the clamping arrangement rests on the cylinder head, while the other side rests on the injector. The injector is appropriately “screwed in” by means of a central screw arrangement in the clamp, ensuring that the injector performs the appropriate movement, even in the case of a decreasing extent of the actuator in the form of a piezoelectric element-washer. Accordingly, the clamp is as it were a kind of return spring. In one possible embodiment, provision can be made for the actuator in the form of a piezoelectric element-washer to be fixed immovably, on the one hand at its contact location with the cylinder head and on the other hand at its contact location with the injector, with the result that, through the change in the extent of the piezoelectric element-washer, a corresponding adjustment of the nozzle tip protrusion is brought about by the relative movement. It is also conceivable for the injector to follow the changes in the extent of the piezoelectric element-washer under the action of gravity, especially when said washer contracts.
According to another possible embodiment, the actuator is a hydraulic actuator. In the operating state, an actuator of this kind is connected to a hydraulic feed, which is subjected to pressure by means of a pump. The actuator can operate in the manner of a hydraulic cylinder, wherein it can be of either single-acting or double-acting design. Whereas, in the former case, just one connection to the hydraulic feed is provided and the active movement of the actuator takes place in only one direction, two connections are provided in the latter case and active movement takes place in both directions. The latter can be preferred in order to provide a more rapid response time. In principle, it is possible with this embodiment too that the actuator simultaneously forms the spacer element. In principle, a hydraulic actuator of this kind can also surround the injector in the form of a circular ring. As an alternative, the actuator can optionally be a pneumatic actuator, even if better precision and a shorter response time can normally be achieved with a hydraulic actuator.
An injector 2, which is part of an injector arrangement 1 according to the present disclosure, is inserted into the cylinder head 14. In the present case, the injector 2 does not differ from injectors known in the prior art. It is not shown sectioned since the details of its internal construction are of no particular significance in the context of the present disclosure. The injector 2 is of very largely symmetrical design relative to a longitudinal axis extending in an axial direction A. At the end in the axial direction A, the injector 2 has a nozzle tip 2.1, in which openings (not shown) for the injection of fuel into the region of the recess 12.1 are arranged. As can be seen, in particular, in the enlarged detail view in
This nozzle tip protrusion V, which is connected to an axial position of the injector 2, is determined inter alia by an actuator 3, which is arranged between the cylinder head 14 and the injector 2.
As a spacer element, the actuator 3 essentially has the shape of a washer, as can be seen in the perspective illustration in
The actuator 3 is likewise part of the injector arrangement 1 and is embodied as a piezoelectric element-washer. The actuator 3 is connected to a power source 6 by leads 4, 5. The leads 4, 5 are connected to ends of the actuator 3 which lie opposite one another in axial direction A. Thus, a voltage between the two leads 4, 5 brings about an expansion of the actuator 3, i.e. of the piezoelectric element-washer, in the axial direction A. It is self-evident that the path of the leads 4, 5 which is shown in
As can be seen, the actuator 3, which can also be referred to as a piezoelectric actuator, is formed by the spacer element. That is to say that, in this case, there is no physical separation between the actuator 3 and the spacer element; instead, a single component performs both functions. In this case, therefore, the piezoelectric actuator 3 is arranged as a spacer element between the injector and the cylinder head and the position of the injector is varied by varying the axial extent of said element, which can be adjusted by means of a power supply. In this case, the piezoelectric actuator 3 can be in the form of a circular ring and have approximately the shape and dimensions of a washer, as already mentioned above. That is to say that, apart from the fact that supply leads for the power supply to the actuator must be provided, this embodiment can be integrated into existing systems particularly easily and without major adaptations.
While
For example, the piezoelectric actuator may be a ring-shaped actuator, as described above with reference to
In another embodiment, adjusting the position of the fuel injector in response to engine operating conditions includes adjusting a fluid pressure of a hydraulic actuator or pneumatic actuator positioned between the fuel injector and the cylinder head (e.g., between the shoulder of the injector and the shoulder of the cylinder head as described above). For example, increasing a distance between the shoulder of the fuel injector and the shoulder of the cylinder head may include increasing a fluid pressure of the hydraulic actuator or pneumatic actuator, while decreasing the distance between the shoulder of the fuel injector and the shoulder of the cylinder head may include decreasing the fluid pressure of the hydraulic actuator or pneumatic actuator.
Instructions for carrying out method 500 and the rest of the methods included herein may be executed by a controller based on instructions stored on a memory of the controller and in conjunction with signals received from sensors of the engine system, such as engine speed sensors, temperature sensors, crankshaft position sensors, etc. The controller may employ engine actuators of the engine system to adjust engine operation, according to the methods described below.
Method 500 includes estimating and/or measuring engine operating conditions at 502 based on one or more outputs of various sensors in the engine system and/or operating conditions of the engine system (e.g., such as various temperature sensors, pressure sensors, etc., as described above). Engine operating conditions may include engine speed and load, rate of engine load increase, fuel pressure, pedal position, fuel injector nozzle opening times, mass air flow rate, turbine speed, compressor inlet pressure, emission control device temperature, etc. Estimating and/or measuring engine operating conditions may also include estimating and/or measuring an amount of protrusion of each fuel injector nozzle tip into each corresponding cylinder. In one example, the amount of protrusion may be based on an amount of energization of a corresponding piezoelectric actuator coupled between each fuel injector and the cylinder head (as described above).
At 504, the method includes determining whether the engine load is below a threshold engine load. For example, the controller may compare an estimated and/or measured value for engine load (determined by the controller based on an output from one or more sensors, as described above) to the threshold engine load in order to determine whether the estimated and/or measured engine load is less than the threshold engine load. In one example, the threshold engine load may be based on an amount of engine load at which a maximum protrusion of the nozzle tip of the fuel injector into the corresponding cylinder is desireable. For example, for engine loads below the threshold engine load, the maximum protrusion of the nozzle tip may increase a combustion efficiency of the cylinder by increasing a mixing of air and fuel within the cylinder.
If the engine load is below the threshold engine load at 504, the method continues to 506 where the method includes maintaining an average protrusion amount of the fuel injector nozzle tip. For example, the average protrusion amount may be determined by the controller over one full combustion cycle of the cylinder (e.g., one cycle including intake stroke, compression stroke, power stroke, and exhaust stroke) immediately prior to 506. The intake stroke, compression stroke, power stroke, and exhaust stroke may be referred to collectively herein as a cylinder cycle, combustion cycle, or engine cycle. In one example, the controller may maintain the average amount of protrusion throughout each stroke such that the nozzle tip protrudes into the cylinder by an equal amount during each of the intake stroke, compression stroke, power stroke, and exhaust stroke. In another example, the controller may maintain the average amount of protrusion throughout the combustion cycle, but the amount of protrusion during one or more strokes may differ from the amount of protrusion during each other stroke. For example, during the intake and compression strokes, the amount of protrusion of the nozzle tip may be greater than the amount of protrusion during the power and exhaust strokes. However, the controller may average the amount of protrusion over each of the four strokes, and the averaged amount may be maintained.
If the engine load is not below the threshold engine load at 504, the method continues to 508 where the method includes adjusting the average protrusion amount of the fuel injector nozzle tip based on engine load. For example, as described above with reference to 506, the controller may average the amount of protrusion of the nozzle tip throughout the intake stroke, compression stroke, power stroke, and exhaust stroke. In response to the estimated and/or measured engine load, the average amount of protrusion may be increased or decreased. In one example, as engine load increases, the average amount of protrusion may be decreased. Similarly, as engine load decreases (but is still greater than the threshold engine load), the average amount of protrusion may increase.
By adjusting the average protrusion amount of the fuel injector nozzle tip into the cylinder in response to the measured and/or estimated engine load, combustion quality may be increased. For example, as engine load increases, a compression ratio of the cylinders may also increase. By decreasing the average amount of protrusion in response to the increased engine load, a fuel injection path from the nozzle tip may be optimized and a mixing of fuel and air may be increased. Additionally, by decreasing the average amount of protrusion in response to the increased engine load, a formation of carbon deposits on the nozzle tip may be reduced due to a decreased amount of exposure of the nozzle tip to high cylinder temperatures.
In another example, by increasing the average amount of protrusion of the nozzle tip in response to decreased engine load, an amount of electric energy supplied to the piezoelectric actuator may be reduced. In other words, as described above, the protrusion amount of the nozzle tip is decreased when the energization of the piezoelectric actuator is increased. In order to increase the average amount of protrusion, the amount of energization of the piezoelectric actuator is decreased. As engine load decreases, the amount of energy supplied to the piezoelectric actuator is also decreased, and the average amount of protrusion of the nozzle tip is increased. By adjusting the protrusion of the nozzle tip in this way, a smaller amount of energy may be expended by an electrical power source of the engine (e.g., a battery) as engine load decreases.
In one example, the average protrusion amount may be determined by the controller over one full combustion cycle of the cylinder (e.g., one cycle including intake stroke, compression stroke, power stroke, and exhaust stroke) immediately prior to 508. In some examples, the controller may adjust (e.g., increase or decrease) the average amount of protrusion by an equal amount for each of the intake stroke, compression stroke, power stroke, and exhaust stroke. In other examples, the controller may adjust the average amount of protrusion by increasing or decreasing the amount of protrusion during one or more strokes, such that the amount of protrusion during the one or more strokes may differ from the amount of protrusion during each other stroke. For example, during the intake and compression strokes, the amount of protrusion of the nozzle tip may be increased relative to the amount of protrusion during the power and exhaust strokes. In this way, the average the amount of protrusion over each of the four strokes may be increased.
While the method 500 is described above with reference to an example fuel injector of the engine, method 500 may be carried out by the controller for one or more fuel injectors of the engine. In one example, the controller may execute method 500 for each fuel injector of the engine. In another example, the controller may execute method 500 for only some fuel injectors of the engine and not others.
Between time t0 and time t1, the engine load at 604 fluctuates slightly, but is below the threshold engine load 606. As a result, the average fuel injector nozzle protrusion at 602 is maintained at a constant amount. Additionally, the energization of the piezoelectric actuator is also maintained at a constant amount. In the example shown by
At time t1, the engine load at 604 has increased by an amount such that the engine load is greater than the threshold engine load at 606. In response to the engine load exceeding the threshold engine load, the piezoelectric actuator is energized as shown by 603, and the average fuel injector nozzle protrusion amount decreases as shown by 602.
Between time t1 and t2, the engine load at 604 increases and reaches a peak at time t2. As the engine load increases, the energization of the piezoelectric actuator also increases at 603, thereby decreasing the average fuel injector nozzle protrusion amount at 602.
At time t2, engine load at 604 begins to decrease. Accordingly, energization of the piezoelectric actuator also begins to decrease at 603, and the average fuel injector nozzle protrusion begins to increase at 602.
Between time t2 and t3, the engine load continues to decrease at 604, the energization of the piezoelectric actuator continues to decrease at 603, and the average fuel injector nozzle protrusion continues to increase at 602.
At time t3, the engine load at 604 decreases below the threshold engine load 606. As a result, the energization of the piezoelectric actuator at 603 decreases, and the piezoelectric actuator is de-energized. The average fuel injector nozzle protrusion at 602 no longer increases and is instead maintained at a constant amount (e.g., an amount corresponding to a maximum amount of protrusion of the nozzle tip).
After time t3, the engine load at 604 does not increase above the threshold engine load at 606. As a result, the average fuel injector nozzle protrusion at 602 is maintained at the constant amount, and the energization of the piezoelectric actuator is also maintained at a constant amount (e.g., zero energization, in this example).
While the example shown by
In each of the examples shown by
As shown in each of
In one example as shown by
In another example as shown by
In another example as shown by
In another example as shown by
By adjusting the protrusion of the fuel injector nozzle tip, the nozzle tip may have an increased amount of protrusion during fuel injection, and may have a decreased amount of protrusion between fuel injections. In this way, the piezoelectric actuator may be energized for a reduced amount of time, thereby reducing a load on electric components of the engine (e.g., a battery). Additionally, the increased protrusion of the nozzle tip may selectively coincide with pilot injections, the main injection, or a combination of pilot injections and the main injection in order to increase engine performance (e.g., reduce knock, reduce nozzle tip temperature, etc.)
Note that the example control and estimation routines included herein can be used with various engine and/or vehicle system configurations. The control methods and routines disclosed herein may be stored as executable instructions in non-transitory memory and may be carried out by the control system including the controller in combination with the various sensors, actuators, and other engine hardware. The specific routines described herein may represent one or more of any number of processing strategies such as event-driven, interrupt-driven, multi-tasking, multi-threading, and the like. As such, various actions, operations, and/or functions illustrated may be performed in the sequence illustrated, in parallel, or in some cases omitted. Likewise, the order of processing is not necessarily required to achieve the features and advantages of the example embodiments described herein, but is provided for ease of illustration and description. One or more of the illustrated actions, operations and/or functions may be repeatedly performed depending on the particular strategy being used. Further, the described actions, operations and/or functions may graphically represent code to be programmed into non-transitory memory of the computer readable storage medium in the engine control system, where the described actions are carried out by executing the instructions in a system including the various engine hardware components in combination with the electronic controller.
It will be appreciated that the configurations and routines disclosed herein are exemplary in nature, and that these specific embodiments are not to be considered in a limiting sense, because numerous variations are possible. For example, the above technology can be applied to V-6, I-4, I-6, V-12, opposed 4, and other engine types. The subject matter of the present disclosure includes all novel and non-obvious combinations and sub-combinations of the various systems and configurations, and other features, functions, and/or properties disclosed herein.
The following claims particularly point out certain combinations and sub-combinations regarded as novel and non-obvious. These claims may refer to “an” element or “a first” element or the equivalent thereof. Such claims should be understood to include incorporation of one or more such elements, neither requiring nor excluding two or more such elements. Other combinations and sub-combinations of the disclosed features, functions, elements, and/or properties may be claimed through amendment of the present claims or through presentation of new claims in this or a related application. Such claims, whether broader, narrower, equal, or different in scope to the original claims, also are regarded as included within the subject matter of the present disclosure.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2015 219 515 | Oct 2015 | DE | national |
| Number | Name | Date | Kind |
|---|---|---|---|
| 4938193 | Raufeisen | Jul 1990 | A |
| 7703727 | Selness | Apr 2010 | B2 |
| 20040197713 | Ohfuji et al. | Oct 2004 | A1 |
| Number | Date | Country |
|---|---|---|
| 686635 | May 1996 | CH |
| 202114508 | Jan 2012 | CN |
| 4022299 | Jan 1992 | DE |
| 102011086719 | Jun 2012 | DE |
| WO 2010004838 | Jan 2010 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 20170101973 A1 | Apr 2017 | US |
