The present description relates generally to a direct fuel injector in a fuel delivery system of an engine.
Fuel delivery systems in internal combustion engines have employed fuel injectors to deliver fuel directly into engine combustion chambers. Previous direct fuel injectors have included nozzles with a small number of orifices that provide jets of fuel to combustion chambers during desired intervals. One example approach shown by Albrodt, in U.S. Pat. No. 9,194,351, is a fuel injection valve. Albrodt discloses a fuel injection valve with a perforated disk at the end of the injector valve. The perforated disk includes outlet openings configured to spray fuel in a pattern that promotes mixing. In particular, the outlet openings arrangement in Albrodt generates swirl in the fuel spray, to increase mixing in a combustion chamber. The inventors have recognized several problems with Albrodt's fuel injection valve as well as other fuel injectors. For example, the disk in the fuel injection valve includes a small number of openings directing a portion of the fuel spray to combustion chamber walls and the piston. Therefore, engines employing Albrodt's fuel injection valve may experience wall wetting. Consequently, the fuel on the walls may not fully combust during the power stroke, thereby increasing emissions (e.g., smoke and particulate matter emissions) and reducing combustion efficiency.
The inventors have recognized the aforementioned problems and facing these problems developed a direct fuel injector, in one example. The direct fuel injector includes a nozzle in fluidic communication with a fuel source. The nozzle including a first set of orifices, each of the orifices in the first set arranged at a first orifice angle on an intake side of the nozzle. The direct fuel injector further includes a second set of orifices, each of the orifices in the second set arranged at a second orifice angle greater than the first orifice angle on an exhaust side of the nozzle. A direct fuel injector with a first set of orifices near the intake valve having a greater orifice angle than a second set of orifices near the exhaust valve enables a spray pattern to be generated that reduces fuel impingement on the cylinder walls and piston. As a result, engines employing the direct fuel injector may achieve emission reductions and combustion efficiency gains. In particular, the spray pattern generated by the fuel injector may reduce smoke and particulate matter emissions.
As one example, the first set of orifices and the second set of orifices may each be arranged in an arc about a central axis of the nozzle and have a common vertical position with regard to a vertical axis. In this way, the injector generates a fuel spray pattern with arcing jets resembling petal shapes. This spray pattern further reduces wall wetting in the cylinder. Consequently, the engine may achieve further emissions reductions and combustion efficiency gains.
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.
The following description relates to a direct fuel injector in a fuel delivery system of an internal combustion engine. The direct fuel injector generates a spray pattern in different arcs that decrease wall wetting. For instance, the nozzle may include different sets of orifices arranged in arcs about a central axis of the nozzle. Each of the sets of orifices may have a different theta angle (θ). Specifically, a first set of orifices adjacent to an intake valve may have a smaller theta angle (θ) than a theta angle (θ) of a second set of orifices adjacent to an exhaust valve. In this way, the fuel injector nozzle generates a spray pattern resembling a petal shape that reduces wall wetting. Specifically, the smaller nozzles and the petal shaped jets generate smaller injected fuel droplets, which have less momentum when compared to previous multi-hole injectors. The reduction in momentum limits the penetration of the spray and enhances the downstream droplet dispersion in the spray. Thus, the spray pattern may make the droplets turn back instead of continue the injection path to hit the wall. Moreover, the petal like spray pattern may also achieve a desired amount of penetration and fuel evaporation in the cylinder to enable combustion stability to be maintained while also achieving the abovementioned wall wetting reductions. Resultantly, emissions may be reduced and combustion efficiency may be increased in engines utilizing the direct fuel injector described herein.
Turning to
An intake system 16 providing intake air to a cylinder 18 is also depicted in
The intake system 16 includes an intake conduit 20 and a throttle 22 coupled to the intake conduit. The throttle 22 is configured to regulate the amount of airflow provided to the cylinder 18. In the depicted example, the intake conduit 20 feeds air to an intake manifold 24. The intake manifold 24 is coupled to and in fluidic communication with intake runners 26. The intake runners 26 in turn provide intake air to intake valves 28. In the illustrated example, two intake valves are depicted in
The intake valves 28 may be actuated by intake valve actuators 30. Likewise, exhaust valves 32 coupled to the cylinder 18 may be actuated by exhaust valve actuators 34. In particular, each intake valve may be actuated by an associated intake valve actuator and each exhaust valve may be actuated by an associated exhaust valve actuator. In one example, the intake valve actuators 30 as well as the exhaust valve actuators 34 may employ cams coupled to intake and exhaust camshafts, respectively, to open/close the valves. Continuing with the cam driven valve actuator example, the intake and exhaust camshafts may be rotationally coupled to a crankshaft. Further in such an example, the valve actuators may utilize one or more of cam profile switching (CPS), variable cam timing (VCT), variable valve timing (VVT) and/or variable valve lift (VVL) systems to vary valve operation. Thus, cam timing devices may be used to vary the valve timing, if desired. It will therefore be appreciated, that valve overlap may occur in the engine, if desired. In another example, the intake and/or exhaust valve actuators, 30 and 34, may be controlled by electric valve actuation. For example, the valve actuators, 30 and 34, may be electronic valve actuators controlled via electronic actuation. In yet another example, cylinder 18 may alternatively include an exhaust valve controlled via electric valve actuation and an intake valve controlled via cam actuation including CPS and/or VCT systems. In still other embodiments, the intake and exhaust valves may be controlled by a common valve actuator or actuation system.
The fuel delivery system 14 provides pressurized fuel to a direct fuel injector 36. The fuel delivery system 14 includes a fuel tank 38 storing liquid fuel (e.g., gasoline, diesel, bio-diesel, alcohol (e.g., ethanol and/or methanol) and/or combinations thereof). The fuel delivery system 14 further includes a fuel pump 40 pressurizing fuel and generating fuel flow to a direct fuel injector 36. A fuel conduit 42 provides fluidic communication between the fuel pump 40 and the direct fuel injector 36. The direct fuel injector 36 is coupled (e.g., directly coupled) to the cylinder 18. The direct fuel injector 36 is configured to provide metered amounts fuel to the cylinder 18. The fuel delivery system 14 may include additional components, not shown in
An ignition system 44 (e.g., distributorless ignition system) is also included in the engine 12. The ignition system 44 provides an ignition spark to cylinder via ignition device 46 (e.g., spark plug) in response to control signals from the controller 100. However, in other examples, the engine may be designed to implement compression ignition, and therefore the ignition system may be omitted, in such an example.
An exhaust system 48 configured to manage exhaust gas from the cylinder 18 is also included in the vehicle 10, depicted in
During engine operation, the cylinder 18 typically undergoes a four stroke cycle including an intake stroke, compression stroke, expansion stroke, and exhaust stroke. During the intake stroke, generally, the exhaust valves close and intake valves open. Air is introduced into the cylinder via the corresponding intake passage, and the cylinder piston moves to the bottom of the cylinder so as to increase the volume within the cylinder. The position at which the piston is near the bottom of the cylinder and at the end of its stroke (e.g., when the combustion chamber is at its largest volume) is typically referred to by those of skill in the art as bottom dead center (BDC). During the compression stroke, the intake valves and exhaust valves are closed. The piston moves toward the cylinder head so as to compress the air within combustion chamber. The point at which the piston is at the end of its stroke and closest to the cylinder head (e.g., when the combustion chamber is at its smallest volume) is typically referred to by those of skill in the art as top dead center (TDC). In a process herein referred to as injection, fuel is introduced into the cylinder. In a process herein referred to as ignition, the injected fuel in the combustion chamber is ignited via a spark from an ignition device (e.g., spark plug) and/or compression, in the case of a compression ignition engine. During the expansion stroke, the expanding gases push the piston back to BDC. A crankshaft converts this piston movement into a rotational torque of the rotary shaft. During the exhaust stroke, in a traditional design, exhaust valves are opened to release the residual combusted air-fuel mixture to the corresponding exhaust passages and the piston returns to TDC.
Furthermore, the controller 100 may be configured to trigger one or more actuators and/or send commands to components. For instance, the controller 100 may trigger adjustment of the throttle 22, intake valve actuators 30, exhaust valve actuators 34, ignition system 44, and/or fuel delivery system 14. Specifically, the controller 100 may be configured to send signals to the ignition device 46 and/or direct fuel injector 36 to adjust operation of the spark and/or fuel delivered to the cylinder 18. Therefore, the controller 100 receives signals from the various sensors and employs the various actuators to adjust engine operation based on the received signals and instructions stored in memory of the controller. Thus, it will be appreciated that the controller 100 may send and receive signals from the fuel delivery system 14.
For example, adjusting the direct fuel injector 36 may include adjusting a fuel injector actuator to adjust the direct fuel injector. In yet another example, the amount of fuel to be delivered via the direct fuel injector 36 may be empirically determined and stored in predetermined lookup tables or functions. For example, one table may correspond to determining direct injection amounts. The tables may be indexed to engine operating conditions, such as engine speed and engine load, among other engine operating conditions. Furthermore, the tables may output an amount of fuel to inject via direct fuel injector to the cylinder at each cylinder cycle. Moreover, commanding the direct fuel injector to inject fuel may include at the controller generating a pulse width signal and sending the pulse width signal to the direct fuel injector.
Additionally, a piston 204 is disposed within the cylinder 18 and connected to a crankshaft 206. The direct fuel injector 36 and specifically a nozzle 208 of the direct fuel injector 36 is shown positioned in an upper region of the cylinder 18 with regard to a central axis 210 of the cylinder 18. Additionally, the direct fuel injector 36 is also positioned horizontally between the intake valve 28 and the exhaust valve 32, in the illustrated example. Specifically, the nozzle 208 of the direct fuel injector 36 is position between the intake valve 28 and the exhaust valve 32 with regard to a horizontal axis. Coordinate axes X and Z are provided for reference. In one example, the Z axis may be parallel to a gravitational axis. Further, the X axis may be a lateral or horizontal axis.
The direct fuel injector 36 is also shown receiving fuel from a fuel source in the fuel delivery system 14, shown in
Continuing with
The orifices in the nozzle 208 can be conceptually divided into different sets. Thus, the nozzle 208 includes a first set of orifices 404 having a plurality of orifices 406. The first set of orifices 404 is arranged on an intake side 408 of the nozzle 208. An exemplary line 410 that may be the dividing line between an exhaust side 409 and intake side 408 of the nozzle 208, extending through the central axis 402, is illustrated in
Each of the orifices 406 included in the first set of orifices 404 may be arranged at a similar orifice angle (e.g., theta angle (θ)). An exemplary orifice angle of one of the orifices included in the nozzle 208, is shown in detail in
Additionally, the nozzle 208 includes a second set of orifices 412 having a plurality of orifices 414. The second set of orifices 412 is arranged on the exhaust side 409 of the nozzle 208. Each of the orifices 414 included in the second set of orifices 412 may be arranged at a similar orifice angle (e.g., theta angle (θ)). Moreover, the orifice angle of the orifices 414 in the second set of orifices 412 may be greater than the orifice angle of the orifices 404 in the first set of orifices 404. In this way, the orifice angles of the sets of orifices are varied to enable fuel to be sprayed in arcs with different angles of penetration to generate a spray pattern conducive to reducing wall wetting. In one particular example, the orifice angle of the orifices 414 in the second set of orifices 412 may be greater than 30° or may specifically be between 35° and 45°. Specifically, in one particular example, the orifice angle of the orifices 414 in the second set of orifices 412 may be 40.1°. However, in other examples, the orifice angle of the orifices in the second set may not be equivalent. For instance, the orifices angles of the orifices in the second set may increase or decrease in a clockwise or counterclockwise direction about the central axis 402.
Furthermore, the nozzle 208 includes a third set of orifices 416. The third set of orifices 416 can be conceptually divided into a first orifice group 418 and a second orifice group 420. The first orifice group 418 includes a plurality of orifices 422 and the second orifice group 420 likewise includes a plurality of orifices 424.
In the illustrated example, the first orifice group 418 and the second orifice group 420 are spaced away from each other. In particular, the first and second orifice groups, 418 and 420, are positioned on opposing sides of the nozzle 208. Furthermore, the third set of orifices 416 is positioned between the first set of orifices 404 and the second set of orifices 412. The plurality of orifices 422 included in the first orifice group 418 extend from the intake side 408 of the nozzle 208 to the exhaust side 409 of the nozzle, across the dividing line 410. Similarly, the plurality of orifices 424 included in the second orifice group 420 also extend from the intake side 408 to the exhaust side 409 of the nozzle 208. Arranging the third set of orifices in this manner enables additional targeting of fuel away from the cylinder walls. Consequently, wall wetting is further decreased during engine combustion.
In one example, the first set of orifices 404, the second set of orifices 412, and/or the third set of orifices 416 may be designed based on engine events to target specific cylinder regions. For instance, the orifice angles of one or more of the sets of orifices may be design to improve air/fuel mixing during partial load, at the same time without jeopardizing emissions performance by keeping the fuel-wall impingement low. In another example, the orifice angles of one or more of the sets of orifices may be design to increase combustion efficiency during a cold start when the air/fuel charge is stratified. Continuing with such an example, the targets of first set of orifices 412, may be designed to deliver fuel to the spark plug region to provide stable combustion.
Each of the orifices included in the third set of orifices 416 may be arranged at a similar orifice angle (e.g., theta angle (θ)). Moreover, the orifice angle of the orifices in the third set of orifices 416 may be greater than the orifice angle of the orifices in the first set of orifices 404 and less than the angle of the orifices in the second set of orifices 412. In this way, the orifice angle (e.g., theta angle) of the orifices increases in a direction toward the intake valves. In one particular example, the orifice angle of the orifices in the third set of orifices 416 may be between 30° and 35°. Specifically, in one particular example, the orifice angle of the orifices in the third set of orifices 416 may be 32.4°. In other examples, however, the orifice angle of the orifices in the third set may not be equivalent. For instance, the orifice angles of the orifices in the third set may increase or decrease in a clockwise or counterclockwise direction.
Further, in
Additionally, in
Further in the illustrated example, each of the orifices in the first, second, and third set of orifices, 404, 412, and 416 respectively, are sequentially spaced apart at equivalent azimuthal angles measured about the central axis 402 of the nozzle 208. An azimuthal angle 426 formed by the intersection of lines 428 extending through centers 430 of two orifices and the central axis 402, is illustrated in
When contrastingly
Additionally,
The slits may have similar angles (e.g., theta angles, azimuthal angles) to the angles of the sets of orifices previously described with regard to the first embodiment of the nozzle, shown in
The invention will further be described in the following paragraphs. In one aspect, a direct fuel injector is provided. The direct fuel injector comprises a nozzle in fluidic communication with a fuel source, including, a first set of orifices, each of the orifices in the first set arranged at a first orifice angle on an intake side of the nozzle, and a second set of orifices, each of the orifices in the second set arranged at a second orifice angle less than the first orifice angle on an exhaust side of the nozzle.
In another aspect, a fuel delivery system is provided. The fuel delivery system comprises a cylinder, an exhaust valve coupled to the cylinder, an intake valve coupled to the cylinder, and a direct fuel injector coupled to the cylinder, the direct fuel injector including, a body receiving fuel from a fuel source, and a nozzle in fluidic communication with the body, the nozzle including a first set of orifices including a plurality of orifices, each of the plurality of orifices in the first set of orifices arranged at a first orifice angle on an intake side of the nozzle, and a second set of orifices including a plurality of orifices, each of the plurality of orifices in the second set of orifices arranged at a second orifice angle on an exhaust side of the nozzle, the first orifice angle less than the second orifice angle, where each of the first orifice angle and the second orifice angle is an angle formed between a centerline of a corresponding orifice and a vertical axis.
In another aspect, a direct fuel injector is provided. The direct fuel injector comprises a body receiving fuel from a fuel source, and a nozzle in fluidic communication with the body, the nozzle including, a first set of orifices including a plurality of orifices, each of the plurality of orifices in the first set of orifices arranged at a first orifice angle and positioned on an intake side of the nozzle, a second set of orifices including a plurality of orifices, each of the plurality of orifices in the second set of orifices arranged at a second orifice angle and positioned on an exhaust side of the nozzle, where the second orifice angle is less than the first orifice angle, and a third set of orifices including a plurality of orifices, each of the plurality of orifices in the third set of orifices arranged at a third orifice angle, where the third orifice angle is less than the second orifice angle and greater than the first orifice angle, where each of the first, second, and third orifice angles is an angle formed between a centerline of a corresponding orifice and a vertical axis.
In any of the aspects herein or combinations of the aspects, each of the first orifice angle and the second orifice angle may be an angle formed between a centerline of a corresponding orifice and a vertical axis.
In any of the aspects herein or combinations of the aspects, the first orifice angle may be less than 30 degrees and the second orifice angle may be greater than 30 degrees.
In any of the aspects herein or combinations of the aspects, the first orifice angle may be between 35 and 45 degrees and the second orifice angle may be between 25 and 35 degrees.
In any of the aspects herein or combinations of the aspects, the direct fuel injector may further include a third set of orifices positioned between the first set of orifices and the second set of orifices, the third set of orifices arranged at a third orifice angle, where the third orifice angle may be less than the second orifice angle and greater than the first orifice angle.
In any of the aspects herein or combinations of the aspects, the third set of orifices may include a first orifice group spaced away from a second orifice group and where the first and second orifice groups may each arranged in an arc extending from the intake side of the nozzle to the exhaust side of the nozzle.
In any of the aspects herein or combinations of the aspects, the first set of orifices and the second set of orifices may each be arranged in an arc about a central axis of the nozzle and have a common vertical position with regard to a vertical axis.
In any of the aspects herein or combinations of the aspects, each of the orifices in the first set of orifices and the second set of orifices may be sequentially spaced apart at equivalent azimuthal angles measured about the central axis of the nozzle.
In any of the aspects herein or combinations of the aspects, a diameter of each of the orifices in the first and second set of orifices may be less than 85 microns.
In any of the aspects herein or combinations of the aspects, the orifices included in each of the first set of orifices and the second set of orifices may have a slit shape with an arc section extending between a first end and a second end.
In any of the aspects herein or combinations of the aspects, the nozzle may be positioned between an intake valve and an exhaust valve with regard to a horizontal axis.
In any of the aspects herein or combinations of the aspects, the fuel delivery system may further include a third set of orifices positioned between the first set of orifices and the second set of orifices, the third set of orifices arranged at a third orifice angle, where the third orifice angle may be less than the second orifice angle and greater than the first orifice angle.
In any of the aspects herein or combinations of the aspects, the first orifice angle may be between 25 and 30 degrees and the second orifice angle may be between 35 and 45 degrees.
In any of the aspects herein or combinations of the aspects, the direct fuel injector may be positioned between the intake valve and the exhaust valve with regard to a horizontal axis.
In any of the aspects herein or combinations of the aspects, the third sets of orifices may extend from the intake side of the nozzle to the exhaust side of the nozzle.
In any of the aspects herein or combinations of the aspects, the first orifice angle may be between 25 and 30 degrees, the second orifice angle may be between 35 and 45 degrees, and the third orifice angle may be between 30 and 35 degrees.
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.
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