Multi-mode starter-generator device transmission with single valve controller
阅读说明：本技术 具有单个阀控制器的多模式起动机-发电机装置变速器 (Multi-mode starter-generator device transmission with single valve controller ) 是由 史蒂文·R·弗莱尔曼 道格拉斯·S·贝斯 于 2020-04-09 设计创作，主要内容包括：为具有发动机的作业车辆提供一种动力控制系统。组合式起动机-发电机装置具有电动机械和齿轮组,所述齿轮组被配置成从电动机械和从发动机接收旋转输入并在两个动力流方向上耦接电动机械和发动机。所述齿轮组在一个方向上在多个相对高扭矩、低转速起动传动比中的一个传动比下操作并在与发电模式相对应的另一方向上以相对低扭矩、高转速传动比操作,所述多个相对高扭矩、低转速起动传动比包括与发动机冷起动模式相对应的第一起动传动比和与发动机热起动模式相对应的第二起动传动比。第一离合器组件和第二离合器组件被选择性耦接至齿轮组以在发动机起动模式期间实现起动传动比。控制阀被流体地耦接以向离合器组件选择性地施加流体压力。(A power control system is provided for a work vehicle having an engine. The combined starter-generator device has an electric machine and a gear set configured to receive rotational input from the electric machine and from the engine and to couple the electric machine and the engine in two power flow directions. The gear set operates in one direction at one of a plurality of relatively high torque, low speed launch gear ratios including a first launch gear ratio corresponding to an engine cold start mode and a second launch gear ratio corresponding to an engine warm start mode and operates in another direction corresponding to a power generation mode at a relatively low torque, high speed launch gear ratio. The first and second clutch assemblies are selectively coupled to the gear set to achieve a starting gear ratio during the engine start mode. The control valve is fluidly coupled to selectively apply fluid pressure to the clutch assembly.)
1. A power control system for a work vehicle having an engine, the power control system comprising:
a combined starter-generator arrangement having:
an electric machine;
a gear set configured to receive rotational input from the electric machine and from the engine and to couple the electric machine and the engine in a first power flow direction and in a second power flow direction, the gear set configured to operate in the first power flow direction at one of a plurality of relatively high torque, low speed cranking gear ratios including a first cranking gear ratio corresponding to an engine cold start mode and a second cranking gear ratio corresponding to an engine hot start mode, the gear set further configured to operate in the second power flow direction at a relatively low torque, high speed gear ratio corresponding to a power generation mode; and
first and second clutch assemblies selectively coupled to the gear set to achieve a first start gear ratio during the engine cold start mode and a second start gear ratio during the engine hot start mode; and
a control valve fluidly coupled to selectively apply fluid pressure to the first and second clutch assemblies.
2. The power control system of claim 1, wherein the control valve is a single solenoid valve.
3. The power control system of claim 1, wherein the first clutch assembly is engaged during the engine cold start mode to cause the gear set to operate according to the first starting gear ratio, disengaged during the engine hot start mode to cause the gear set to operate according to the second starting gear ratio, and engaged while in the second power flow direction; and wherein the second clutch assembly is disengaged during the engine cold start mode to cause the gear set to operate according to the first starting gear ratio, engaged during the engine hot start mode to cause the gear set to operate according to the second starting gear ratio, and engaged while in the second power flow direction.
4. The power control system of claim 1, further comprising a controller configured to generate command signals to the control valve to selectively actuate the first clutch assembly between a first engaged position and a first disengaged position and to selectively actuate the second clutch assembly between a second engaged position and a second disengaged position.
5. The power control system according to claim 4,
wherein, in the engine cold start mode, the controller is configured to generate a command signal for the control valve such that the first clutch assembly is in the first engaged position and the second clutch assembly is in the second disengaged position,
wherein in the engine warm start mode, the controller is configured to generate command signals for the control valve such that the first clutch assembly is in the first disengaged position and the second clutch assembly is in the second engaged position, and
wherein in the power generation mode, the controller is configured to generate a command signal for the control valve such that the first clutch assembly is in the first engaged position and the second clutch assembly is in the second engaged position.
6. The power control system according to claim 5,
wherein, in the engine cold start mode, the controller is configured to generate a command signal for the control valve to apply a first fluid pressure value,
wherein in the engine warm start mode, the controller is configured to generate a command signal for the control valve to apply a second fluid pressure value that is greater than the first fluid pressure value, and
wherein in the power generation mode, the controller is configured to generate a command signal for the control valve to apply a third fluid pressure value that is between the first and second fluid pressure values.
7. The power control system according to claim 6,
wherein the first clutch assembly includes a first spring configured to urge the first clutch assembly into the first engaged position and a first piston located adjacent a first chamber and when supplied with fluid pressure opposing the first spring and urging the first clutch assembly into the first disengaged position,
wherein the second clutch assembly includes a second spring configured to urge the second clutch assembly into the second disengaged position and a second piston located adjacent a second chamber and when supplied with fluid pressure opposing the second spring and urging the second clutch assembly into the second engaged position, and
wherein the combined starter-generator device further includes a fluid passage fluidly coupling the control valve to the first and second chambers.
8. The power control system of claim 7, wherein the fluid passageway is formed by a common branch fluidly coupled to the control valve, a first branch extending between the common branch and the first chamber, and a second branch extending between the common branch and the second chamber.
9. The power control system according to claim 1,
wherein the gear set is bidirectional, wherein in the first power flow direction, the gear set receives input power in a first clock direction from the electric machine and outputs power in a second clock direction opposite the first clock direction to the engine; and is
Wherein, in the second power flow direction, the input power from the engine is in the second clock direction and the output power to the electric machine is in the second clock direction.
10. The power control system of claim 9, further comprising a belt and a pulley coupled to the gear set and the electric machine, wherein input power in the first power flow direction is transmitted from the electric machine to the gear set through the belt and the pulley, and wherein in the first power flow direction the belt and the pulley rotate in the first clock direction and in the second power flow direction the belt and the pulley rotate in the second clock direction.
11. The power control system of claim 10, further comprising a single belt tensioner that applies a tensioning force to a first side of the belt in both the first power flow direction and the second power flow direction.
12. The power control system of claim 1, wherein the starter-generator arrangement further includes a third clutch assembly that is engaged during the first and second starting gear ratios and disengaged when in the second power flow direction.
13. The power control system of claim 12, wherein the third clutch assembly is a one-way mechanically actuated clutch.
14. The power control system according to claim 1,
wherein the gear set comprises a compound epicyclic gear train comprising first and second stage sun gears, first and second stage planet gears, first and second stage carriers, and a ring gear; and is
Wherein the first stage planet gears have a different number of teeth than the second stage planet gears.
15. The power control system of claim 14, wherein rotational power from the electric machine moves in the first power flow direction from the first stage sun gear to the ring gear and to the engine, and wherein rotational power from the engine moves in the second power flow direction from the ring gear to the first stage sun gear and to the electric machine.
16. The power control system of claim 15, wherein the combined starter-generator device further includes a third clutch assembly coupled to the gear set and disposed between the engine and the electric machine, and wherein the third clutch assembly is configured to engage to couple the second stage carrier to the housing of the gear set during the first and second starting gear ratios, and to disengage to decouple the second stage carrier from the housing of the gear set when in the second power flow direction.
17. The power control system of claim 16, wherein the third clutch assembly is a one-way mechanically actuated clutch.
18. A power system for a work vehicle, comprising:
an engine;
an electric machine;
a combined starter-generator arrangement having:
a gear set configured to receive rotational input from the electric machine and from the engine and to couple the electric machine and the engine in a first power flow direction and in a second power flow direction, the gear set configured to operate in the first power flow direction at one of a plurality of relatively high torque, low speed cranking gear ratios including a first cranking gear ratio corresponding to an engine cold start mode and a second cranking gear ratio corresponding to an engine hot start mode, the gear set further configured to operate in the second power flow direction at a relatively low torque, high speed gear ratio corresponding to a power generation mode;
a first clutch assembly coupled to the gear set, wherein the first clutch assembly is engaged during the engine cold start mode to cause the gear set to operate according to the first starting gear ratio, disengaged during the engine hot start mode to cause the gear set to operate according to the second starting gear ratio, and engaged while in the second power flow direction;
a second clutch assembly coupled to the gear set, wherein the second clutch assembly is disengaged during the engine cold start mode to cause the gear set to operate according to the first starting gear ratio, engaged during the engine hot start mode to cause the gear set to operate according to the second starting gear ratio, and engaged while in the second power flow direction; and is
A third clutch assembly engaged when in a first power flow direction during the engine cold start mode and the engine hot start mode and disengaged when in a second power flow direction during the generate mode; and
a single control valve fluidly coupled to selectively apply fluid pressure to the first and second clutch assemblies.
19. The powertrain system of claim 18, further comprising a controller configured to generate command signals for the control valve to selectively actuate the first clutch assembly between a first engaged position and a first disengaged position and to selectively actuate the second clutch assembly between a second engaged position and a second disengaged position,
wherein in the engine cold start mode, the controller is configured to generate a command signal for the control valve to apply a first fluid pressure value such that the first clutch assembly is in the first engaged position and the second clutch assembly is in the second disengaged position,
wherein in the engine hot start mode, the controller is configured to generate a command signal for the control valve to apply a second fluid pressure value such that the first clutch assembly is in the first disengaged position and the second clutch assembly is in the second engaged position, the second fluid pressure value is greater than the first fluid pressure value, and
wherein in the power generation mode, the controller is configured to generate a command signal for the control valve to apply a third fluid pressure value that is intermediate the first and second fluid pressure values such that the first clutch assembly is in the first engaged position and the second clutch assembly is in the second engaged position.
20. The power system of claim 19 wherein the gear set comprises a compound epicyclic gear train comprising first and second stage sun gears, first and second stage planet gears, first and second stage carriers, and a ring gear;
wherein the first stage planet gears have a different number of teeth than the second stage planet gears; and is
Wherein rotational power from the electric machine moves in the first power flow direction from the first stage sun gear to the ring gear and to the engine, and wherein rotational power from the engine moves in the second power flow direction from the ring gear to the first stage sun gear and to the electric machine;
wherein the combined starter-generator device further comprises a third clutch assembly coupled to the gear set and disposed between the engine and the electric machine;
wherein the first clutch assembly is configured to engage to couple the first stage sun gear to an input member coupled to the electromechanical machine during the first start gear ratio and in the second power flow direction, and the first clutch assembly is configured to disengage to decouple the first stage sun gear from the input member during the second start gear ratio;
wherein the second clutch assembly is configured to disengage during the first start gear ratio to decouple the second stage sun gear from the input member, and the second clutch assembly is configured to engage during the second start gear ratio and in the second power flow direction to couple the second stage sun gear to the input member; and is
Wherein the third clutch assembly is configured to engage to couple the second stage carrier to the housing of the gear set during the first and second starting gear ratios and to disengage to decouple the second stage carrier from the housing of the gear set when in the second power flow direction.
Technical Field
The present disclosure relates to work vehicle power systems including arrangements for starting and generating power from mechanical power equipment.
Background
While it is becoming increasingly common to employ hybrid power sources (e.g., engines and electric motors), work vehicles, such as those used in agriculture, construction, and forestry, and other conventional vehicles may be powered by internal combustion engines (e.g., diesel engines). In any event, the engine remains the primary power source of the work vehicle and requires mechanical input from the starter to initiate rotation of the crankshaft and reciprocation of the pistons within the cylinders. The torque requirements to start the engine are high, especially for large diesel engines that are common in heavy machinery.
The work vehicle additionally includes a subsystem that requires electrical energy. To power these subsystems of the work vehicle, an alternator or generator may be used to utilize a portion of the engine power to produce AC or DC electrical energy. The battery of the work vehicle is then charged by converting the current from the alternator. Conventionally, a belt, straight belt or serpentine belt, couples the output shaft of the engine to an alternator to produce AC electrical power. The torque demand to generate current from an operating engine is significantly lower than the torque demand for engine starting. In order to properly transmit power between the engine and the battery to both start the engine and generate electrical energy, many different components and devices are typically required, creating problems with size, cost, and complexity.
Disclosure of Invention
The present disclosure provides a combined engine starter and generator device with an integrated transmission, such as may be used in a work vehicle for engine cold start and generating electrical energy, serving the dual purpose of an engine starter and alternator, with more robust power transfer to and from the engine in both cases.
In one aspect, the present disclosure provides a combined starter-generator for a work vehicle having an engine, the starter-generator including an electric machine and a gear set configured to receive rotational input from the electric machine and from the engine.
In another aspect, the present disclosure provides a drivetrain assembly that includes an engine, an electric machine, and a gear set configured to receive rotational input from the electric machine and from the engine.
The details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features and advantages will be apparent from the description and drawings, and from the claims.
Drawings
FIG. 1 is a schematic side view of an example work vehicle in the form of an agricultural tractor in which the disclosed integrated starter-generator apparatus may be used;
FIG. 2 is a simplified, partial isometric view of an engine of the work vehicle of FIG. 1, illustrating an example of a mounting location of an example starter-generator device;
FIG. 3 is a portion of a power transmission arrangement of the work vehicle of FIG. 1 with an example starter-generator arrangement;
FIG. 4 is a cross-sectional view of a power transmission assembly of an example starter-generator arrangement that may be implemented in the work vehicle of FIG. 1;
FIG. 5 is a more detailed view of a portion of the power transmission assembly of FIG. 4 for an example starter-generator arrangement;
FIG. 6 is a cross-sectional view of the power transfer assembly of FIG. 4, depicting a schematic diagram of a power flow path in a first engine start mode of the example starter-generator arrangement;
FIG. 7 is a cross-sectional view of the power transfer assembly of FIG. 4, depicting a schematic illustration of a power flow path in a second engine starting mode of the example starter-generator arrangement;
FIG. 8 is a cross-sectional view of the power transfer assembly of FIG. 4, depicting a schematic illustration of a power transmission path in a power generation mode of the example starter-generator arrangement;
FIG. 9 is a cross-sectional view of another exemplary power transmission assembly of the example starter-generator arrangement that may be implemented in the work vehicle of FIG. 1;
FIGS. 10 and 11 are more detailed views of a portion of the power transmission assembly of FIG. 9 for an example starter-generator arrangement;
FIG. 12 is a graph depicting the relationship between control valve pressure, clutch torque capacity and output torque during an engine start mode of the power transmission assembly of FIG. 9;
FIG. 13 is another more detailed view of a portion of the power transmission assembly of FIG. 9 for the exemplary starter-generator arrangement; and
FIG. 14 is a graph depicting the relationship between control valve pressure, clutch torque capacity and output torque during a power generation mode of the power transmission assembly of FIG. 9;
in the various drawings, the same or similar reference numbers refer to the same or similar elements.
Detailed Description
One or more example embodiments of the disclosed starter-generator apparatus are described below, as shown in the inset of the drawings briefly described above. Various modifications to the example embodiments may be apparent to those skilled in the art.
As used herein, unless otherwise limited or modified, a list of elements that have one or more of the "or at least one of the" preceding phrases "separated by a conjunctive term (e.g.," and ") indicates a configuration or arrangement that may include the individual elements in the list, or any combination thereof. For example, "at least one of A, B and C" or "one or more of A, B and C" indicates that it is possible to have only a, only B, only C, or any combination of two or more of A, B and C (e.g., a and B; B and C; a and C or A, B and C).
As used herein, the term "axial" refers to a dimension that is generally parallel to the axis of rotation, axis of symmetry, or centerline of one or more components. For example, in a cylinder or disc having a centerline and opposing, generally circular ends or faces, an "axial" dimension may refer to a dimension extending generally parallel to the centerline between the opposing ends or faces. In some instances, the term "axial" may be used with respect to components that are not cylindrical (or otherwise radially symmetric). For example, for a rectangular housing containing a rotating shaft, the "axial" dimension may be considered to be a dimension generally parallel to the axis of rotation of the shaft. Further, the term "radially" as used herein may refer to the size or relationship of components relative to a line extending outward from a common centerline, axis, or similar reference (e.g., a line in a plane of a cylinder or disk perpendicular to the centerline or axis). In some instances, the components may be considered "radially" symmetric, even if one or both of the components is not cylindrical (or otherwise radially symmetric). Furthermore, the terms "axial" and "radial" (or any derivative thereof) may include directional relationships other than precise alignment with (e.g., tilt relative to) true axial and radial dimensions, provided that the relationship is primarily in the respective nominal axial or radial dimension.
Many conventional vehicle power systems include an internal combustion engine and/or one or more batteries (or other chemical sources of power) that power various components and subsystems of the vehicle. In some electric vehicles, a battery pack powers the entire vehicle including the drive wheels to move the vehicle. In hybrid gasoline-powered and electric vehicles, the prime mover power may alternate between engine power and electric motor power, or the engine power may be supplemented by electric motor power. In still other conventional vehicles, the electrical system is used to initiate an engine start and run the non-drive electrical system of the vehicle. In the latter case, the vehicle typically has a starter motor powered by the vehicle battery to rotate the engine crankshaft to move the piston within the cylinder. In other scenarios, the power system may provide a boost device to an operating engine.
Some engines (e.g., diesel engines) initiate combustion by compression of fuel, while other engines rely on a battery-powered spark generator (e.g., a spark plug) to initiate combustion. Once the engine is operating at a sufficient speed, the power system may obtain engine power to power the electrical system and to charge the battery. Typically, such power harvesting is performed with an alternator or other type of electrical generator. The alternator converts Alternating Current (AC) electrical energy to Direct Current (DC) electrical energy that is usable by the battery and vehicle electrical components by passing the AC electrical energy through an inverter (e.g., a diode rectifier). Conventional alternators utilize power from an engine by coupling the rotor of the alternator to the output shaft of the engine (or a component coupled thereto). Historically, this has been accompanied by the use of a dedicated belt, but in more modern vehicles, the alternator is one of several devices coupled to (and therefore powered by) the engine via a single "serpentine" belt.
In certain applications, such as in certain heavy machinery and work vehicles, conventional arrangements having separate starter and generator components may be disadvantageous. Such separate components require separate housings, which may require separate sealing or protection from the working environment and/or occupy separate locations within the limited space of the engine compartment. Other engine compartment layout complexity issues may also arise.
One or more example embodiments of an improved vehicle powertrain system that addresses one or more of these (or other) issues with conventional systems are described below. In one aspect, the disclosed system includes a combined or integrated device that performs the engine starting function of the starter motor and the power generating function of the generator. The device is referred to herein as an integrated starter-generator device ("ISG" or "starter-generator"). At least in some embodiments of the system, this term is used herein with no certainty as to the type of power (i.e., AC or DC power) generated by the device. In some embodiments, the starter-generator device may be used to generate electricity in a manner that one skilled in the art may consider the "generator" device to directly produce DC current. However, as used herein, the term "generator" will be meant to produce electrical energy having a static polarity or an alternating polarity (i.e., AC or DC). Thus, in the particular case of a starter-generator arrangement, the generating function is similar to that of a conventional alternator and produces AC power which is then rectified to DC power either within or outside the starter-generator arrangement.
In some embodiments, the starter-generator arrangement may include a direct mechanical power coupling to the engine that avoids the use of a belt between the engine and the starter-generator arrangement. For example, a starter-generator arrangement may include within its housing a power transfer assembly having a gear set directly coupled to an output shaft of the engine. The gear set may take any of a variety of forms including arrangements with meshing spur or other gears and with one or more planetary gear sets. A large gear reduction ratio may be achieved through the transmission assembly so that a single electric machine (i.e., motor or generator) may be used and operated at a suitable rotational speed for one or more of the engine start type and the electric generation type. Direct power coupling between the starter-generator device and the engine may increase system reliability, cold start performance, and power generation of the system.
Additionally, in certain embodiments, the starter-generator arrangement may have a power transfer assembly that automatically and/or selectively shifts gear ratios (i.e., shifts between power flow paths having different gear ratios). By way of example, the transmission assembly may include one or more passive engagement components that automatically engage or disengage when driven in a particular direction, and/or one or more active engagement components that are commanded to engage or disengage. For example, a passive engagement component, such as a one-way clutch (e.g., a roller clutch or a sprag clutch), may be used to enable power transfer through the power flow path in the engine starting direction; and active engagement components (such as friction clutch assemblies) may be used to effect power transfer through other power flow paths. In this manner, a bi-directional clutch or other clutch (or other) configuration may be employed to perform the starting and generating functions using appropriate control hardware. Due to the bi-directional nature of the power transfer assembly, the power transmission belt arrangement may be implemented with only a single belt tensioner, thereby providing a relatively compact and simple assembly. In addition to providing torque in two different directions of power flow, the gear sets may be configured and arranged to provide power transfer from the electric machine to the engine at one of two different rotational speeds (e.g., according to different gear ratios). The selection of the rotational speed may provide additional functionality and flexibility to the power transfer assembly. For example, a lower speed or "first start" gear ratio may be provided to facilitate a cold engine start, and a higher speed "second start" gear ratio may be provided to facilitate a warm engine start (or engine boost).
Control of the power transfer assembly with respect to the active clutch assembly may take various forms. In one example, separate and dedicated control valves may be utilized to separately operate the two active clutch assemblies. In further examples, a single control valve may be utilized to operate both clutch assemblies to perform a designated function. Each of the embodiments will be discussed in more detail below.
Referring to the drawings, an example work vehicle powertrain will be described in detail as a powertrain component. As will be apparent from the discussion herein, the disclosed system may be advantageously used in various settings and with various machines. For example, referring now to fig. 1, a powertrain system (or driveline component) 110 may be included in a
Briefly,
As schematically shown, the
The starter-
As introduced above, the
In general, the
Additionally, the
In one example, the starter-
Referring briefly to fig. 2, fig. 2 depicts a simplified, partial isometric view of starter-
Referring additionally to fig. 3, fig. 3 is a simplified schematic illustration of a power transmission belt arrangement 200 between the
The
The power transmission belt arrangement 200 includes a first pulley 210 disposed on the second power transmitting element 135 of the
Due to the bi-directional configuration, the power transmission belt arrangement 200 may include only a single belt tensioner 240 for applying tension to a single side of the belt 230 in both directions D1, D2. The use of a single belt tensioner 240 to tension the belt 230 is advantageous over designs requiring multiple belt tensioners because it reduces components and complexity. As described below, the bi-directional configuration and associated simplified power transmission belt arrangement 200 can be achieved by the bi-directional nature of the gear sets in the
In one example, FIG. 4 depicts a cross-sectional view of a
From FIG. 4, a first side 304 of the
The
The
In one example, the gear set 320 includes a first stage sun gear 322, the first stage sun gear 322 being formed by a shaft 324 having a first end 325 and a second end 326. The first end 325 of the first stage sun gear shaft 324 is oriented toward the first side 304 of the
In one example, the first stage planet gears 328 include a single circumferential row of one or more planet gears, although other embodiments may include radially stacked rows, each row having an odd number of planet gears. The first stage planet gears 328 are supported by a first stage
The gear set 320 also includes a
The
The gear set 320 also includes a second
Additionally, second stage sun gear shaft 344 may include a series of splines that mesh with a set of second stage planet gears 350. The second stage planet gears 350 are supported by a second stage
The second stage
In addition to the overrunning
Any suitable mechanism for engaging and disengaging the first and second
The first
Referring to fig. 5 in addition to fig. 4, fig. 5 is a more detailed view of a portion of fig. 4. As shown, the SAHR
The SAHR
The SAHR piston 372 is coupled to the SAHR clutch plate 368 and is positioned relative to the input shaft clutch element 316 to form a chamber 376. As schematically shown, the chamber 376 is fluidly coupled to a source of fluid pressure from the
The second
The HASR
HASR
The HASR piston 388 is coupled to the HASR clutch plate 384 and is positioned relative to the input shaft clutch element 316 to form a chamber 390. As schematically illustrated, the chamber 390 is fluidly coupled to a second source of fluid pressure from the
When the hydraulic pressure in the chamber 390 is released, the HASR clutch spring 386 is used to urge the HASR
As introduced above, the variable power flow path elements of the
As introduced hereinabove, the
Referring initially to FIG. 6, FIG. 6 is a cross-sectional view of a power transmission assembly 132 (similar to
In the engine cold start mode, the
The first stage planet gears 328 drive the first stage
Since the number of the
In one example, the
Referring now to FIG. 7, FIG. 7 is a cross-sectional view of a power transmission assembly 132 (similar to
In the engine warm start mode, the
Since the number of second stage planet gears 350 in the power flow path is odd in the radial direction (e.g., 1), the second stage planet gears 350 drive the
In one example, the
Referring now to FIG. 8, FIG. 8 is a partial cross-sectional view of a power transmission assembly 132 (similar to
After one or both of the two engine start modes, the
In one example, the
The
Referring now to fig. 9, fig. 9 is a cross-sectional view of a power transfer assembly 400 that may be implemented into a starter-
The power transfer assembly 400 is similar to the
As shown, the SAHR
The HASR
In this embodiment and in contrast to the embodiment of fig. 4, the SAHR
Referring to FIG. 10, FIG. 10 is a partial closer view of the power transmission assembly 400 during the engine cold start mode; and referring to fig. 11, fig. 11 is a partial closer view of the power transfer assembly 400 during the engine hot start mode. Referring additionally to fig. 12, fig. 12 is a
The valve pressure at
To transition to the engine warm start mode, the control valve 158 increases the valve pressure. As the pressure increases, the clutch torque capacity of the SAHR
The valve pressure at
In the generate mode,
As noted above, the increase in valve pressure operates to decrease the clutch torque capacity of the SAHR
Thus, various embodiments of a vehicle electrical system have been described, including an integrated starter-generator arrangement. Various delivery components may be included in the device, thus reducing the space occupied by the system. The transfer assembly may provide and transition between a plurality of rotational speeds or gear ratios. One or more clutch arrangements may be used to apply torque to the gear sets of the transfer assembly in both power flow directions. Direct mechanical engagement with the engine shaft reduces complexity and improves system reliability. The use of planetary gear sets in the transfer assembly provides high gear reduction and torque capacity in a compact spatial range and reduces backlash. Due to the bi-directional nature of the power transfer assembly, the power transmission belt arrangement may be implemented with only a single belt tensioner, thereby providing a relatively compact and simple assembly. Additionally, by using a power transmission belt arrangement having a belt and pulleys to couple the electric machine with and transmit power between the electric machine and the power transmission assembly, rather than connecting and coupling the electric machine directly to the power transmission assembly, the electric machine may be located remotely from the transmission assembly to optimally fit the engine in the vehicle engine compartment. Additionally, by using belts and pulleys to couple the electric machine to the power transmission assembly, additional gear ratios (e.g., 4:1 gear ratios) may be achieved. The embodiments discussed above include a double planetary gear set with a sun gear in an outer ring gear configuration to provide an engine warm start mode and an engine cold start mode, and a ring gear in an outer ring gear configuration to provide a power generation mode. In this way, three modes of assembly may be provided. The control of the gear sets may be implemented with dedicated control valves or a single control valve.
The following examples are also provided and numbered for reference.
1. A power control system for a work vehicle having an engine, the power control system comprising: a combined starter-generator arrangement having: an electric machine; a gear set configured to receive rotational input from the electric machine and from the engine and to couple the electric machine and the engine in a first power flow direction and in a second power flow direction, the gear set configured to operate in the first power flow direction at one of a plurality of relatively high torque, low speed launch gear ratios including a first launch gear ratio corresponding to an engine cold start mode and a second launch gear ratio corresponding to an engine hot start mode, the gear set further configured to operate in the second power flow direction at a relatively low torque, high speed gear ratio corresponding to a power generation mode; and first and second clutch assemblies selectively coupled to the gear set to achieve a first start gear ratio during the engine cold start mode and a second start gear ratio during the engine hot start mode; and a control valve fluidly coupled to selectively apply fluid pressure to the first and second clutch assemblies.
2. The power control system of example 1, wherein the control valve is a single solenoid valve.
3. The power control system of example 1, wherein the first clutch assembly is engaged during the engine cold start mode to cause the gear set to operate according to the first starting gear ratio, disengaged during the engine hot start mode to cause the gear set to operate according to the second starting gear ratio, and engaged while in the second power flow direction; and wherein the second clutch assembly is disengaged during the engine cold start mode to cause the gear set to operate according to the first starting gear ratio, engaged during the engine hot start mode to cause the gear set to operate according to the second starting gear ratio, and engaged while in the second power flow direction.
4. The power control system of example 1, further comprising a controller configured to generate command signals to the control valve to selectively actuate the first clutch assembly between a first engaged position and a first disengaged position and to selectively actuate the second clutch assembly between a second engaged position and a second disengaged position.
5. The power control system of example 4, wherein, in the engine cold start mode, the controller is configured to generate a command signal for the control valve such that the first clutch assembly is in the first engaged position and the second clutch assembly is in the second disengaged position, wherein in the engine warm start mode, the controller is configured to generate a command signal for the control valve, such that the first clutch assembly is in the first disengaged position and the second clutch assembly is in the second engaged position, and wherein in the power generation mode, the controller is configured to generate a command signal for the control valve, such that the first clutch assembly is in the first engaged position and the second clutch assembly is in the second engaged position.
6. The power control system of example 5, wherein, in the engine cold start mode, the controller is configured to generate the command signal for the control valve to apply a first fluid pressure value, wherein, in the engine hot start mode, the controller is configured to generate the command signal for the control valve to apply a second fluid pressure value, the second fluid pressure value being greater than the first fluid pressure value, and wherein, in the power generation mode, the controller is configured to generate the command signal for the control valve to apply a third fluid pressure value, the third fluid pressure value being between the first fluid pressure value and the second fluid pressure value.
7. The power control system of example 6, wherein the first clutch assembly includes a first spring configured to urge the first clutch assembly into the first engaged position and a first piston adjacent a first chamber and resisting the first spring and urging the first clutch assembly into the first disengaged position when supplied with fluid pressure, wherein the second clutch assembly includes a second spring configured to urge the second clutch assembly into the second disengaged position and a second piston adjacent a second chamber and resisting the second spring and urging the second clutch assembly into the second engaged position when supplied with fluid pressure, and wherein the combined starter-generator device further includes a fluid passage, the fluid passage fluidly couples the control valve to the first chamber and the second chamber.
8. The power control system of example 7, wherein the fluid passageway is formed by a common branch fluidly coupled to the control valve, a first branch extending between the common branch and the first chamber, and a second branch extending between the common branch and the second chamber.
9. The power control system of example 1, wherein the gear set is bi-directional, wherein in the first power flow direction, the gear set receives input power from the electric machine in a first clock direction and outputs power to the engine in a second clock direction opposite the first clock direction; and wherein in the second power flow direction, the input power from the engine is in the second clock direction and the output power to the electric machine is in the second clock direction.
10. The power control system of example 9, further comprising a belt and a pulley coupled to the gear set and the electric machine, wherein input power in the first power flow direction is transmitted from the electric machine to the gear set through the belt and the pulley, and wherein in the first power flow direction the belt and the pulley rotate in the first clock direction and in the second power flow direction the belt and the pulley rotate in the second clock direction.
11. The power control system of example 10, further comprising a single belt tensioner that applies a tensioning force to a first side of the belt in both the first power flow direction and the second power flow direction.
12. The power control system of example 1, wherein the starter-generator arrangement further includes a third clutch assembly that is engaged during the first and second starting gear ratios and disengaged when in the second power flow direction.
13. The power control system of example 12, wherein the third clutch assembly is a one-way mechanically actuated clutch.
14. The power control system of example 1, wherein the gear set includes a compound epicyclic gear train including first and second stage sun gears, first and second stage planet gears, first and second stage carriers, and a ring gear; and wherein the first stage planet gears have a different number of teeth than the second stage planet gears.
15. The power control system of example 14, wherein rotational power from the electric machine moves in the first power flow direction from the first stage sun gear to the ring gear and to the engine, and wherein rotational power from the engine moves in the second power flow direction from the ring gear to the first stage sun gear and to the electric machine, and wherein the combined starter-generator device further includes a third clutch assembly coupled to the gear set and disposed between the engine and the electric machine, and wherein the third clutch assembly is configured to engage during the first and second starting gear ratios to couple the second stage carrier to the housing of the gear set, and is configured to disengage in the second power flow direction to couple the second stage carrier to the housing of the gear set The stage carrier is decoupled from the housing of the gear set.
As will be appreciated by one skilled in the art, certain aspects of the disclosed subject matter may be embodied as a method, a system (e.g., a work vehicle control system included in a work vehicle), or a computer program product. Accordingly, certain embodiments may be embodied entirely in hardware, entirely in software (including firmware, resident software, micro-code, etc.) or in a combination of software and hardware aspects (as well as others). Furthermore, certain embodiments may take the form of a computer program product on a computer-usable storage medium having computer-usable program code embodied in the medium.
Any suitable computer usable or computer readable medium may be utilized. The computer usable medium may be a computer readable signal medium or a computer readable storage medium. A computer-usable or computer-readable storage medium (including storage devices associated with a computing device or client electronic device) may be, for example but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of the computer-readable medium would include the following: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), or an optical storage device. In the context of this document, a computer-usable or computer-readable storage medium may be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device.
A computer readable signal medium may include a propagated data signal with computer readable program code embodied therein, for example, at a base frequency or as part of a carrier wave. Such a propagated signal may take any of a variety of forms, including, but not limited to, electro-magnetic, optical, or any suitable combination thereof. A computer readable signal medium may be non-transitory and may be any computer readable medium that is not a computer readable storage medium and that can communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device.
Aspects of certain embodiments described herein may be described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the disclosure. It will be understood that each group of any such flowchart illustrations and/or block diagrams, and combinations of blocks in such flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instructions which implement the function/act specified in the flowchart and/or block diagram block or blocks.
The computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented method such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.
Any flow charts and block diagrams in the figures or similar discussions above may illustrate the architecture, functionality, and operation of possible implementations of systems, methods and computer program products according to various embodiments of the present disclosure. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that, in some alternative implementations, the functions noted in the block (or otherwise described herein) may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks (or operations) may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of any block diagram and/or flowchart illustration, and combinations of blocks in any block diagram and/or flowchart illustration, can be implemented by special purpose hardware-based systems that perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
The description of the present disclosure has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the disclosure in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the disclosure. The embodiments specifically referenced herein were chosen and described in order to best explain the principles of the disclosure and its practical application, and to enable others of ordinary skill in the art to understand the disclosure and to recognize various alternatives, modifications, and variations to the described examples. Accordingly, various embodiments and implementations other than those explicitly described are within the scope of the following claims.
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