Vehicle Stopping Transmission Control System and Method

Abstract

A control system includes a transmission and a controller configured to receive a vehicle stop command; determine a ground speed; compare the ground speed with first and second predetermined speed thresholds; generate a downshift command when the ground speed exceeds the second predetermined speed threshold; generate a shuttle shift command when the ground speed is greater than the first predetermined speed threshold and less than or equal to the second predetermined speed threshold; determine whether the transmission is operating in a first mode or a second mode when the ground speed is less than or equal to the first predetermined speed threshold; select a four-way clutch once the operating mode is determined; and engage the selected four-way clutch at least partially to slow down or stop the vehicle.

Description

TECHNICAL FIELD

[0001] The present disclosure relates generally to control systems and methods for work vehicles, and more particularly, to transmission control systems and methods for stopping work vehicles. BACKGROUND

[0002] Work vehicles, such as tractors, wheel loaders, and other large agricultural, construction, or forestry vehicles, operate in various environments to perform a variety of functions. Such vehicles can be operated manually by an operator, autonomously by a controller, or semi-autonomously as a combination of manual and autonomous operation. At times, it can be desirable to supplement or functionally replace the primary vehicle braking system to slow or stop the work vehicle, particularly in situations that lend themselves to autonomous control. SUMMARY

[0003] The present disclosure provides a vehicle stop transmission control system and method.

[0004] In one aspect, the present disclosure provides a control system for operating a powertrain of a work vehicle, the powertrain having a power source configured to generate power for an output shaft. The control system includes a transmission operably positioned between the power source and the output shaft and configured to selectively transfer power from the power source to drive the output shaft in a first direction according to at least one forward mode and in a second direction according to at least one reverse mode. The transmission includes at least one forward input clutch configured to be engaged when transferring power in the at least one forward mode, at least one reverse input clutch configured to be engaged when transferring power in the at least one reverse mode, a first output clutch configured to be engaged when transferring power in a first mode of the at least one forward mode or the at least one reverse mode, and a second output clutch configured to be engaged when transferring power in a second mode of the at least one forward mode or the at least one reverse mode. The control system further includes a controller having a processor and a memory architecture and configured to receive or generate a vehicle stop command, determine a ground speed of the work vehicle, compare the ground speed to a first predetermined speed threshold and a second predetermined speed threshold, generate at least one downshift command for the transmission to perform a downshift within the transmission when the ground speed exceeds the second predetermined speed threshold, generate at least one shuttle shift command for the transmission to perform a shuttle shift within the transmission when the ground speed is greater than the first predetermined speed threshold and less than or equal to the second predetermined speed threshold, determine whether the transmission is operating in the first mode or the second mode as an operating mode when the ground speed is less than or equal to the first predetermined speed threshold, select a four-square clutch from the first output clutch and the second output clutch once the operating mode is determined, including selecting the second output clutch as the selected four-square clutch when the transmission is operating in the first mode and selecting the first output clutch as the selected four-square clutch when the transmission is operating in the second mode, and cause the selected four-square clutch to at least partially engage to slow or stop the work vehicle.

[0005] In further aspects, the present disclosure provides a method of operating a powertrain of a work vehicle, the powertrain having a power source configured to generate power for an output shaft, a transmission operably positioned between the power source and the output shaft and configured to selectively transfer power from the power source to drive the output shaft in a first direction according to at least one forward mode and in a second direction according to at least one reverse mode. The transmission includes at least one forward input clutch configured to be engaged when transferring power in the at least one forward mode, at least one reverse input clutch configured to be engaged when transferring power in the at least one reverse mode, a first output clutch configured to be engaged when transferring power in a first mode of the at least one forward mode or the at least one reverse mode, and a second output clutch configured to be engaged when transferring power in a second mode of the at least one forward mode or the at least one reverse mode. The method includes receiving or generating a vehicle stop command for slowing and stopping the work vehicle, determining, with a controller on the work vehicle, a ground speed of the work vehicle, comparing, by the controller, the ground speed to a first predetermined speed threshold and a second predetermined speed threshold, generating, by the controller, at least one downshift command for the transmission to perform a downshift within the transmission when the ground speed exceeds the second predetermined speed threshold, generating, by the controller, at least one shuttle shift command for the transmission to perform a shuttle shift within the transmission when the ground speed is greater than the first predetermined speed threshold and less than or equal to the second predetermined speed threshold, determining, by the controller, whether the transmission is operating in the first mode or the second mode as an operating mode when the ground speed is less than or equal to the first predetermined speed threshold, selecting, by the controller, a four-square clutch from the first output clutch and the second output clutch once the operating mode is determined, including selecting the second output clutch as the selected four-square clutch when the transmission is operating in the first mode and selecting the first output clutch as the selected four-square clutch when the transmission is operating in the second mode, and causing the selected four-square clutch to at least partially engage to slow or stop the work vehicle.

[0006] The details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features and advantages will become apparent from the description, the drawings, and the claims. BRIEF DESCRIPTION OF DRAWINGS

[0007] Figure 1 is a side view of an example work vehicle implementing a vehicle stop transmission control system according to the present disclosure;

[0008] Figure 2 is a schematic view of a vehicle stop transmission control system according to an exampleFigure 1 a schematic diagram of a powertrain of a vehicle stop transmission control system of a vehicle;

[0009] Figure 3 a vehicle stop transmission control system of a vehicle Figure 1 a dataflow diagram of a controller of a vehicle stop transmission control system of a vehicle;

[0010] Figure 4 a flowchart of a vehicle stop transmission control method according to an example;

[0011] Figure 5 a clutch command schedule used in a vehicle stop transmission control system of a vehicle Figure 1 according to an example; and

[0012] Figure 6 a further clutch command schedule used in a vehicle stop transmission control system of a vehicle Figure 1 according to an example.

[0013] Like reference symbols in different drawings indicate the same element. DETAILED DESCRIPTION

[0014] One or more exemplary embodiments of the disclosed powertrains, vehicles, and transmission control systems and methods are described below as shown in the accompanying drawings described briefly above. Various modifications to the exemplary embodiments can be conceived by one skilled in the art.

[0015] Work vehicles operate at work sites to perform various functions under different conditions. During operation, at least some tasks and functions can be performed autonomously (or“automatically,” used interchangeably herein) including functions associated with braking under certain conditions, such as obstacle avoidance and hill parking. It is beneficial to implement vehicle braking with local hardware, even in autonomous cases, for cost, efficiency, and / or performance. As an example of such local hardware in some work vehicles, aspects of a transmission can be designed to slow down portions of the powertrain, for example, to dissipate energy in the powertrain during“shuttle shifting” to change the direction of the vehicle. As described in more detail below, the transmission can also be used to slow down and subsequently stop the vehicle during vehicle stop transmission operation in different cases and embodiments. Such transmission operation can be useful as part of autonomous functions because it eliminates the need for additional hardware that would otherwise be required to automatically actuate other vehicle brakes (e.g., axle, wheel, or parking brakes). Instead, vehicle stop transmission operation can be implemented by a vehicle stop transmission control system managed by a controller and by a suitable power-shift transmission based on vehicle and environmental parameters.

[0016] Generally, the transmission can include any number of axles, gears, clutches, and other power transfer elements to appropriately transfer and manipulate the torque and speed of the power flow between an input coupled to a power source and an output coupled to a wheel. In particular, the clutches can be actuated by commands from a controller based on a power shift operation plan to appropriately modulate the power desired or required for normal operation, as well as a braking function during vehicle stop transmission operation discussed in greater detail below.

[0017] In one example, the transmission can include one or more input clutches and at least two output clutches, where at least one of the input clutches and at least one of the output clutches are engaged during typical propulsion operation; and when performing a vehicle stop transmission operation, the engaged input clutch can be modulated and / or subsequently disengaged while at least partially engaging one or more of the previously disengaged output clutches to dissipate energy from the output shaft and wheels to slow, stop, and hold the vehicle. In effect, the vehicle stop transmission control system allows for the "four-squaring" of one or more output clutches of a power shift transmission to dissipate excess energy within the powertrain to slow, stop, and park the vehicle.

[0018] In some examples, the vehicle stop transmission control system can perform the four-squaring of one or more of the output clutches as a function of the vehicle's ground speed. In particular, based on the ground speed, the vehicle stop transmission control system can initiate a downshift and / or a shuttle shift within the transmission in order to slow the ground speed to a value more suitable for four-squaring. In one example, when the ground speed is greater than a shuttle shift threshold, the vehicle stop transmission control system can perform a downshift prior to the four-squaring operation; when the ground speed is greater than a four-squaring speed threshold and less than or equal to a shuttle shift speed threshold, the vehicle stop transmission control system can perform a shuttle shift prior to the four-squaring operation; and when the ground speed is less than or equal to the four-squaring speed threshold, the vehicle stop transmission control system implements the four-squaring operation immediately. Additionally and as described below, the vehicle stop transmission control system can modulate the input and output clutches (as well as the four-squaring clutches) as a function of a predetermined clutch command schedule in order to provide a smooth and efficient deceleration and stoppage of the work vehicle.

[0019] Reference Figure 1The work vehicle 100 can include a vehicle stop transmission control system 102 that is provided and implemented with a controller 104, one or more components of the powertrain 106, one or more sensors 108, and / or selected additional components of the vehicle 100. As described in greater detail below, the vehicle stop transmission control system 102 is used to dissipate vehicle and / or powertrain energy to slow, stop, and / or park the vehicle 100 (generally, “vehicle stop transmission operation”). Vehicle stop transmission operation performed by the vehicle stop transmission control system 102 can be particularly useful in the context of automatic stops, such as for obstacle avoidance and / or hill parking, as discussed in greater detail below. In one example, the vehicle stop transmission control system 102 can be used independent of (or in conjunction with) other brakes of the vehicle 100 (e.g., axle brakes, service brakes, or parking brakes).

[0020] In Figure 1 the vehicle 100 is depicted as a tractor. However, it will be appreciated that other configurations are possible, including configurations in which the vehicle 100 operates as one of a different kind of tractor, a wheel loader, a harvester, a skidder, a grader, or various other work vehicle types. It will also be appreciated that the disclosed powertrain 106 can also be used in non-work vehicle and non-vehicle applications (e.g., stationary power installations). In addition to elements within the powertrain 106, the vehicle 100 can include one or more auxiliary components or systems, such as steering, braking, and actuation systems, to appropriately maneuver or manipulate various aspects of the vehicle 100. Generally, the powertrain 106 includes one or more engines, motors, batteries, and power transmission elements to provide power to the vehicle 100 in forward and reverse directions, as well as to provide mechanical or electrical power to various additional systems of the vehicle 100.

[0021] Generally, the controller 104 controls operation of the vehicle stop transmission control system 102, the powertrain 106, and other aspects of the vehicle 100, including any of the functions described herein. The controller 104 can be configured as a computing device with an associated processor device and memory architecture, configured as a hydraulic, electrical, or electro-hydraulic controller, or otherwise. As such, the controller 104 can be configured to perform various computing and control functions with respect to the vehicle 100. The controller 104 can be in communication with various other systems or devices of the vehicle 100. For example, the controller 104 can be in electronic or hydraulic communication with various sensors (e.g., the sensors 108), actuators, and other devices within the vehicle 100 (or external thereto). Some of these sensors 108 are discussed in greater detail below. The controller 104 can communicate with other systems or devices, including other controllers, in various known manners, including via a CAN bus (not shown) of the vehicle 100, via wireless, wired, or hydraulic communication means, or otherwise. In some embodiments, the controller 104 can be configured to receive input commands and interact with an operator through a human-machine interface or operator interface. The vehicle 100 can also include a control lever or other operator input device that facilitates interaction with the power transfer elements of the powertrain 106 discussed herein, although in some examples, the controller 104 can implement one or more functions autonomously or automatically (e.g., without operator input).

[0022] The controller 104 can be considered a vehicle controller that controls overall operation of the vehicle 100, including control of the powertrain 106, autonomous and / or semi-autonomous control of the vehicle 100, and / or control of elements of the powertrain 106, such as the transmission. In some examples, the controller 104 can be collectively referred to as a group of control elements that can be dedicated to control of various elements or systems of the vehicle 100.

[0023] The sensors 108 generally represent a collection of vehicle sensors that implement the functions described herein. For example, the sensors 108 can include one or more speed sensors to collect information associated with determining a speed (e.g., ground speed) of the vehicle and / or various aspects of the powertrain 106. The sensors 108 can also include one or more position sensors (e.g., GPS or other motion sensors) and / or tilt sensors. The sensors 108 also include one or more obstacle detection sensors, such as light detection and ranging (LIDAR) sensors, infrared and / or visible light cameras, radio detection and ranging (RADAR) sensors, laser sensors, ambient light sensors, and / or boundary sensors.

[0024] The controller 104 can use information collected by the sensors 108 to identify conditions within an operating environment of the vehicle 100 or otherwise identify conditions associated with the vehicle 100 (e.g., powertrain conditions, planned path information, obstacle maps, object identifications, etc.). In response, the controller 104 can implement one or more aspects of autonomous or semi-autonomous vehicle control. For example, the controller 104 can generate commands for one or more aspects of the powertrain 106, including the braking system, throttle system, and steering system. In particular examples discussed below, the controller 104 can generate an automatic transmission command to stop the vehicle 100 for one or more reasons, particularly in response to an obstacle and / or to implement hill hold.

[0025] With respect to obstacle avoidance, the sensors 108 collect information associated with the vehicle’s environment and the vehicle 100 and provide the information to the controller 104. The controller 104 can evaluate the environmental and / or vehicle information to identify an obstacle in a planned path of the vehicle 100. When the obstacle is within the planned path of the vehicle 100, the controller 104 can generate a vehicle stop command for the transmission as a vehicle stop transmission operation of the vehicle stop transmission control system 102, as discussed in more detail below.

[0026] With respect to hill hold, as discussed above, the sensors 108 can collect information associated with the vehicle’s environment and the vehicle 100 and provide the information to the controller 104. Such information can include location or motion information from which vehicle tilt information can be determined. Such information can also include powertrain information, such as torque and other parameters within the powertrain 106. The controller 104 can evaluate the environmental and / or vehicle information to identify conditions suitable for hill hold. Such conditions can include the vehicle 100 being positioned on a hill or other type of incline, where gravity would otherwise cause the vehicle 100 to roll down the incline. When a hill hold condition is identified, the controller 104 can generate a vehicle stop command for the transmission 124 as a vehicle stop transmission operation of the vehicle stop transmission control system 102, as discussed in more detail below.

[0027] Additional details regarding the vehicle stop transmission operation of the vehicle stop transmission control system 102 are provided below. The operation can be implemented automatically based on one of the conditions discussed above and other conditions or manually based on a command initiated by a vehicle operator.

[0028] Further reference is made to Figure 2 , Figure 2 is in Figure 1a schematic view of a vehicle stop transmission control system 102 implemented within a vehicle 100. In the discussion below, various exemplary configurations of shafts, gears, and other power transmission elements are described. It will be appreciated that various alternative configurations are possible within the spirit of the present disclosure.

[0029] Figure 2 The view depicts a controller 104 coupled to portions of a powertrain 106, including a power source 122 and a transmission 124. The power source 122 can be any suitable power source, including an internal combustion engine, a continuously variable power source (CVP) (e.g., an electric or hydraulic motor), or a combination of an engine and a CVP. The transmission 124 can be any device that transmits power from the power source 122 to an output. In general, the transmission 124 can be a power-shift transmission, where “gears” and / or speed or power ratios changes can be implemented automatically based on operating conditions and a shift schedule under the command of the controller 104, including when under load from the power source 122.

[0030] In one example, the transmission 124 can be considered to have a plurality of gears 130, 140, 160, 180, 200, 220, 230. In this example, the transmission 124 is considered to have seven (7) gears 130, 140, 160, 180, 200, 220, 230. Figure 2 In the transmission 124 of this example, seven (7) gears 130, 140, 160, 180, 200, 220, 230 are provided as an example. Each of the gears 130, 140, 160, 180, 200, 220, 230 is associated with one or more shafts 132, 142, 162, 182, 202, 222, 232 about which various power transmission elements are mounted. In this particular example, the first gear shaft 132 can be considered to be an input shaft for receiving power from the power source 122, and the seventh gear shaft 232 can be considered to be an output shaft that drives one or more components of the vehicle 100 (e.g., one or more ground-engaging wheels, implements, and / or power transmission devices).

[0031] As described below, the transmission 124 can include a plurality of clutches 150, 152, 170, 172, 190, 192, 210, 212 that can be manipulated based on commands from the controller 104 to fully transfer torque between two elements in an engaged position or break the transfer of torque between two elements in a disengaged position, thereby providing a plurality of power flow paths through the transmission 124 at various speeds and directions. Moreover, the clutches 150, 152, 170, 172, 190, 192, 210, 212 can be partially engaged or modulated to cause the respective clutch elements to slip relative to one another, thereby partially transferring or inhibiting torque transfer depending on the mode of operation. The arrangement of the clutches 150, 152, 170, 172, 190, 192, 210, 212 within the stages 130, 140, 160, 180, 200, 220, 230 is described below.

[0032] As an example, one or more of the clutches (especially the clutches 190, 210) can be used to inhibit torque transfer in other portions of the transmission 124 to create internal energy losses by dissipating energy (e.g., with heat and friction) to slow and / or stop the vehicle 100 when a vehicle stop transmission operation is performed by the vehicle stop transmission control system 102, which is described in more detail below in the explanation of the Figure 2 of the transmission 124.

[0033] The first stage 130 includes a first gear 134 and a second gear 136 mounted for rotation with a first stage shaft 132. The second stage 140 includes a third gear 144, a fourth gear 146, and a fifth gear 148 mounted for rotation with a second stage shaft 142. The second stage 140 also includes a first input clutch 150 having a first element mounted to the third gear 144 and a second element mounted to the fifth gear 148, and a second input clutch 152 having a first element mounted to the fourth gear 146 and a second element mounted to the fifth gear 148. As described, each of the first input clutch 150 and the second input clutch 152 can be positioned in an engaged position, a disengaged position, or a partially engaged position to control power flow between the respective portions and the associated gears.

[0034] The third stage 160 includes a sixth gear 164, a seventh gear 166, and an eighth gear 168 mounted for rotation with the third stage shaft 162. The third stage 160 also includes a third input clutch 170 having a first element mounted to the sixth gear 164 and a second element mounted to the eighth gear 168, and a fourth input clutch 172 having a first element mounted to the seventh gear 166 and a second element mounted to the eighth gear 168. Each of the third and fourth input clutches 170, 172 can be positioned in an engaged position, a disengaged position, or a partially engaged position to control power flow between the respective portions and associated gears.

[0035] The fourth stage 180 includes a ninth gear 184, a tenth gear 186, and an eleventh gear 188 mounted for rotation with the fourth stage shaft 182. The fourth stage 180 also includes a first output clutch 190 having a first element mounted to the ninth gear 184 and a second element mounted to the eleventh gear 188, and a second output clutch 192 having a first element mounted to the tenth gear 186 and a second element mounted to the eleventh gear 188. The fourth stage 180 also includes a twelfth gear 194 mounted to the first element of the second output clutch 192 (and thus the tenth gear 186). Each of the first and second output clutches 190, 192 can be positioned in an engaged position or a disengaged position to control power flow between the respective portions and associated gears. Additionally, the first and second output clutches 190, 192 can be partially engaged or modulated to partially transfer (or dampen) torque.

[0036] The fifth stage 200 includes a thirteenth gear 204, a fourteenth gear 206, and a fifteenth gear 208 mounted for rotation with the fifth stage shaft 202. The fifth stage 200 also includes a first output clutch 210 having a first element mounted to the thirteenth gear 204 and a second element mounted to the fifteenth gear 208, and a second output clutch 212 having a first element mounted to the fourteenth gear 206 and a second element mounted to the fifteenth gear 208. Each of the third and fourth output clutches 210, 212 can be positioned in an engaged position or a disengaged position to control power flow between the respective portions and associated gears. Additionally, the third and fourth output clutches 210, 212 can be partially engaged or modulated to partially transfer (or dampen) torque.

[0037] The sixth stage 220 includes a sixteenth gear 224, a seventeenth gear 226, and an eighteenth gear 228 mounted for rotation with the sixth stage shaft 222. The seventh stage 230 includes a nineteenth gear 234 mounted for rotation with the seventh stage shaft 232.

[0038] The stages 130, 140, 160, 180, 200, 220, 230 are arranged such that control of the clutches 150, 152, 170, 172, 190, 192, 210, 212 implements a selected power flow path between the first stage shaft 132 and the seventh stage shaft 232. In the depicted example, the first gear 134 of the first stage 130 is meshed or otherwise engaged with the third gear 144 of the second stage 140 and the sixth gear 164 of the third stage 160. The second gear 136 of the first stage 130 is meshed or otherwise engaged with the fourth gear 146 of the second stage 140 and the seventh gear 166 of the third stage 160. Further, the fifth gear 148 of the second stage 140 is meshed or otherwise engaged with the eighth gear 168 of the third stage 160 and the eleventh gear 188 of the fourth stage 180. The ninth gear 184 of the fourth stage 180 is meshed or otherwise engaged with the thirteenth gear 204 of the fifth stage 200 and the sixteenth gear 224 of the sixth stage 220. The tenth gear 186 of the fourth stage 180 is meshed or otherwise engaged with the fourteenth gear 206 of the fifth stage 200. The twelfth gear 194 of the fourth stage 180 is meshed or otherwise engaged with the seventeenth gear 226 of the sixth stage 220. The eleventh gear 188 of the fourth stage 180 is meshed or otherwise engaged with the fifth gear 148 of the second stage 140 and the fifteenth gear 208 of the fifth stage 200. The eighteenth gear 228 of the sixth stage 220 is meshed or otherwise engaged with the nineteenth gear 234 of the seventh stage 230.

[0039] During operation, at least one of the input clutches 150, 152, 170, 172 can be selected with at least one of the output clutches 190, 192, 210, 212 to implement a number of different speed ratios and directions. In one example, the input clutches 150, 152, 170, 172 and the output clutches 190, 192, 210, 212 are manipulated to achieve eight different speed ratios (or “modes” or “gears”) in each of a forward direction and a reverse direction (e.g., modes F1-F8 and modes R1-R8). Generally, the first input clutch 150 and the second input clutch 152 are used to implement the forward modes (F1-F8), and the third input clutch 170 and the fourth input clutch 172 are used to implement the reverse modes (R1-R8).

[0040] While the arrangement can vary, in the depicted transmission 124, the first forward mode (Fl) has a lower speed and higher torque than the second forward mode (F2), which in turn has a lower speed and higher torque than the third forward mode (F3), and so on. Similarly, the first reverse mode (Rl) has a lower speed and higher torque than the second reverse mode (R2), which in turn has a lower speed and higher torque than the third reverse mode (R3), and so on. The particular clutches 150, 152, 170, 172, 190, 192, 210, 212 that are engaged for each mode (Fl through F8, Rl through R8) are listed in Table 1.

[0041]

[0042]

[0043] Table (1)

[0044] As an example and with reference to Table (1), in the first forward mode (Fl), the first input clutch 150 and the first output clutch 190 are engaged. From this, torque from the power source 122 is transmitted through the first gear 134 and the third gear 144 and across the first input clutch 150 to the first stage shaft 132. The torque is then transmitted through the fifth gear 148 and across the first output clutch 190 to the eleventh gear 188. The torque is transmitted from the first output clutch 190 through the ninth gear 184 of the fourth stage 180 to the sixteenth gear 224 of the sixth stage 220, through the sixth stage shaft 222 to the eighteenth gear 228, and through the nineteenth gear 234 to the output shaft 232. The second forward mode (F2) is similar to the first forward mode (Fl) except that the torque is transmitted through the second input clutch 152 instead of the first input clutch 150. The third and fourth forward modes (F3, F4) use the first and second input clutches 150, 152 and the third output clutch 210, respectively. The fifth and sixth forward modes (F5, F6) use the first and second input clutches 150, 152 and the second output clutch 192, respectively; the seventh and eighth forward modes (F7, F8) use the first and second input clutches 150, 152 and the fourth output clutch 212, respectively.

[0045] As an example and with reference to Table (1), in a first reverse mode (Rl), the third input clutch 170 and the first output clutch 190 are engaged. Thereby, torque from the power source 122 is transmitted through the sixth gear 164 and through the third input clutch 170 to the first stage shaft 132. The torque is then transmitted through the eighth gear 168, through the fifth gear 148, through the eleventh gear 188, and through the first output clutch 190. The torque is transmitted from the first output clutch 190 through the ninth gear 184 of the fourth stage 180 to the sixteenth gear 224 of the sixth stage 220, through the sixth stage shaft 222 to the eighteenth gear 228, and through the nineteenth gear 234 to the output shaft 232. In the reverse modes (Rl through R8), the output shaft 232 is driven in an opposite direction than in the forward modes (Fl through F8). The second reverse mode (R2) is similar to the first reverse mode (Rl) except that the torque is transmitted through the fourth input clutch 172 instead of the third input clutch 170. The third and fourth reverse modes (R3, R4) use the third and fourth input clutches 170, 172, respectively, and the third output clutch 210. The fifth and sixth reverse modes (R5, R6) use the third and fourth input clutches 170, 172, respectively, and the second output clutch 192; and the seventh and eighth reverse modes (R7, R8) use the third and fourth input clutches 170, 172, respectively, and the fourth output clutch 212.

[0046] Thereby, during operation, the controller 104 commands the clutches 150, 152, 170, 172, 190, 192, 210, 212 to cycle through the forward and reverse modes, e.g., from Fl to F2 to F3 (or from Rl to R2 to R3), and so on, including from F8 back to F7 to F6 (or from R8 to R7 to R6), and so on. Moving from a higher mode to a lower mode (e.g., from F8 to F7, etc., or from R8 to R7, etc.) can be considered a "downshift." Additionally, sometimes the controller 104 performs a "shuttle shift," in which the clutches 150, 152, 170, 172, 190, 192, 210, 212 are manipulated to change the output direction, e.g., from one of the forward modes to one of the reverse modes, or from one of the reverse modes to one of the forward modes.

[0047] As introduced above, the vehicle stop transmission control system 102 can also implement transmission braking in one or more modes (Fl through F8, Rl through R8) to stop the vehicle 100 and park the vehicle at a stationary location. For example, in certain modes, one of the output clutches that is not used as part of a torque transfer path can be modulated and / or engaged to inhibit power flow, thereby slowing and stopping the vehicle. Such transmission braking operations can be considered to be “quadrization,” and the clutch that is at least partially engaged can be considered to be a “quad clutch.”

[0048] In one example, transmission braking can be implemented in the first four forward modes (Fl through F4) and the first four reverse modes (Rl through R4). The quad clutches that can be used to implement braking in the transmission 124 are also summarized in Table (1). For example and as described above, in the first forward mode (Fl), the first input clutch 150 and the first output clutch 190 are engaged to transfer power from the power source 122 to the first stage shaft 132, through the first gear 134 and the third gear 144, through the first input clutch 150, through the fifth gear 148 and the eleventh gear 188, through the first output clutch 190, through the ninth gear 184 of the fourth stage 180 to the sixteenth gear 224 of the sixth stage 220, through the sixth stage shaft 222 to the eighteenth gear 228, and via the nineteenth gear 234 to the output shaft 232. During this power flow, the third output clutch 210 of the fifth stage 200 can be modulated and / or engaged to inhibit rotation of the elements of the fourth stage 180, thereby inhibiting power flow to the output shaft 232. In the second forward mode (F2), the third output clutch 210 is also a quad clutch, while the first output clutch 190 is a quad clutch for the third and fourth forward modes (F3, F4).

[0049] Similar operations can occur in the reverse modes (R1-R8). For example, as described above, in the first reverse mode (R1), the third input clutch 170 and the first output clutch 190 are engaged to transfer power from the power source 122 to the first stage shaft 132, through the sixth gear 164, through the third input clutch 170, through the eighth gear 168, through the fifth gear 148, through the eleventh gear 188, through the first output clutch 190, through the ninth gear 184 of the fourth stage 180 to the sixteenth gear 224 of the sixth stage 220, through the sixth stage shaft 222 to the eighteenth gear 228, and via the nineteenth gear 234 to the output shaft 232. During this power flow, the third output clutch 210 of the fifth stage 200 can be modulated and / or engaged to inhibit rotation of the elements of the fourth stage 180, thereby inhibiting power flow to the output shaft 232. In the second reverse mode (R2), the third output clutch 210 is also a four-square clutch, while the first output clutch 190 is a four-square clutch for the third and fourth reverse modes (R3, R4).

[0050] Reference can be made to Figure 3 Additional details are provided regarding the operation of the vehicle stop transmission operation of the vehicle stop transmission control system 102, Figure 3 is a dataflow diagram illustrating an embodiment of the controller 104 implementing the operation of the vehicle stop transmission system 102. In this case, the controller 104 can be considered a vehicle controller, a dedicated transmission controller, or a distributed controller (or controllers). Regarding Figure 3 With respect to this aspect of the vehicle stop transmission control system 102, the controller 104 can be organized as one or more functional units or modules 110, 112 (e.g., software, hardware, or a combination thereof), including a vehicle stop condition module 110 and a vehicle transmission stop module 112. By way of example, the modules 110, 112 and other aspects of the controller 104 can be implemented with a processing architecture such as a processor 114 and a memory 116, as well as suitable communication interfaces. For example, the controller 104 can implement the modules 110, 112 with the processor 114 based on programs or instructions stored in the memory 116.

[0051] During operation, the controller 104, and in particular the vehicle stop condition module 110, can receive various types of input signals or data, including input signals or data from the sensors 108. Generally, the vehicle stop condition module 110 evaluates or otherwise processes the data and, in certain conditions, generates a vehicle stop command for the vehicle transmission stop module 112 to stop the vehicle 100. In some examples, the vehicle stop condition module 110 can also receive input signals representing requests in the form of stop vehicle requests by an operator via an operator interface device (not shown) to stop the work vehicle 100. Typically, however, the vehicle stop condition module 110 can derive a vehicle stop condition and generate a vehicle stop command based on input data from the sensors 108, as will now be described.

[0052] As shown, the sensors 108 can generate input data in the form of obstacle data and hill hold data for the vehicle stop condition module 110, as well as other data such as ground speed and other parameters. As introduced above, the obstacle data can include environmental and / or vehicle information that enables the vehicle stop condition module 110 to identify an obstacle in the planned path of the vehicle 100 and, in response, generate a vehicle stop command to be implemented by the vehicle transmission stop module 112 and the transmission 124, as discussed in greater detail below. Also as introduced above, the hill hold data can include information associated with the vehicle environment and the vehicle 100, such as position or kinematic information from which vehicle tilt information can be determined and powertrain information. The vehicle stop condition module 110 can evaluate the hill hold data to identify conditions suitable for "hill holding" and, in response, generate a vehicle stop command to be implemented by the vehicle transmission stop module 112 and the transmission 124, as discussed below.

[0053] Upon receiving the vehicle stop command, the vehicle transmission stop module 112 generates a command for the transmission 124 to implement the vehicle stop. In one example and / or certain conditions, the vehicle transmission stop module 112 can generate a vehicle stop command suitable for immediately implementing a vehicle stop transmission operation. In other examples and / or particular conditions, the vehicle transmission stop module 112 can generate a downshift clutch command and / or a shuttle shift clutch command for the transmission 124 prior to generating a vehicle stop clutch command. In particular, the vehicle transmission stop module 112 can generate a downshift clutch command and / or a shuttle shift clutch command for the transmission 124 in accordance with ground speed and / or other transmission data generated by the sensors 108. The following will refer to the downshift clutch command and / or the shuttle shift clutch command as the downshift command. Figure 4Method 300 discusses additional details regarding the generation of various transmission commands (e.g., downshift clutch commands, shuttle clutch commands, and vehicle stop clutch commands) by the vehicle transmission stop module 112 taking into account ground speed and transmission data. Furthermore, reference will be made below. Figure 5 and Figure 6 Further details are discussed regarding the operation of stopping the transmission via the vehicle stop clutch command.

[0054] According to Figure 4 The flowchart of method 300 depicted in the diagram describes the operation of stopping the transmission in a vehicle within a broader context. In one example, method 300 can be derived from the above reference. Figures 1 to 3 The vehicle stop transmission control system 102 described herein may be implemented, while in other examples, other mechanisms may be used. Figure 4 The vehicle stop transmission operation can be manually or automatically activated by the operator. Typically, method 300 is described below in the context of a normally operating vehicle 100 (e.g., propulsion, maneuvering, and / or performing a work task).

[0055] Initially, during operation of vehicle 100, in step 302, the controller 104 of vehicle 100 receives environmental and / or vehicle data, for example, from sensor 108. As described above, the environmental and / or vehicle data may include information about potential obstacles in the planned path, the tilt or angular position of vehicle 100, the speed and / or powertrain parameters of vehicle 100 (such as the current transmission mode and / or torque condition).

[0056] In step 304, controller 104 evaluates environmental and / or vehicle data based on the conditions for automatic stopping. For example, controller 104 may check environmental and / or vehicle data to determine whether an obstacle is in the planned path of vehicle 100, and / or whether vehicle 100 is positioned on a ramp so that ramp parking is desired. If these conditions are not suitable for automatic stopping, method 300 returns to step 302, in which environmental and / or vehicle data continues to be received and evaluated. If these conditions are suitable for automatic stopping, method 300 proceeds to step 306.

[0057] In step 306, where these conditions warrant automatic stopping, controller 104 generates and / or executes a transmission command to stop vehicle 100. As described above, the generation and execution of the vehicle stopping transmission operation can be performed by the same or different control architectures on vehicle 100. In any case, controller 104 "receives" the command to be executed (e.g., generated internally or elsewhere).

[0058] In step 308, the controller 104 initiates implementation of the vehicle stop transmission command by comparing the ground speed to a first predetermined value or threshold value representative of a four-square clutch speed threshold value. Generally, the four-square clutch speed threshold value reflects an operational or torque limit value (expressed as vehicle speed) of the selected four-square clutch. Such limit value can reflect the ability of the selected four-square clutch to dissipate energy. For example, it can be undesirable to engage the selected four-square clutch at relatively high vehicle speeds. The four-square clutch speed threshold value can be stored in the controller 104 or otherwise accessed by the controller 104, such as in a lookup table.

[0059] In step 308, when the vehicle speed is greater than the four-square clutch speed threshold value, the method 300 proceeds to step 310. In step 308, when the vehicle speed is less than or equal to the four-square clutch speed threshold value, the method 300 proceeds to step 318.

[0060] In step 310, the controller 104 compares the ground speed to a second predetermined value or threshold value representative of a shuttle shift speed threshold value. Generally, the shuttle shift speed threshold value reflects an operational or torque limit value (expressed as vehicle speed) of the clutches involved in the shuttle shift. Such limit value can reflect the ability of the shuttle shift clutches to decelerate and change direction during the shuttle shift. For example, it can be undesirable to implement a shuttle shift at relatively high vehicle speeds. The shuttle shift speed threshold value can be stored in the controller 104 or otherwise accessed by the controller 104, such as in a lookup table. In one example, the shuttle shift speed threshold value can be a greater speed than the four-square clutch speed threshold value, while in other examples the shuttle shift speed threshold value and associated steps (e.g., steps 310, 314, 316) can be omitted.

[0061] In step 310, when the vehicle speed is greater than the shuttle shift speed threshold value, the method 300 proceeds to step 312. In step 310, when the vehicle speed is less than or equal to the shuttle shift speed threshold value, the method 300 proceeds to step 314. As such and as described below, the effect of steps 308 and 310 is that the method 300 proceeds to step 312 to perform a downshift when the ground speed is greater than the shuttle shift speed threshold value, proceeds to step 314 to perform a shuttle shift when the ground speed is greater than the four-square speed threshold value and less than or equal to the shuttle shift threshold value, and proceeds to step 318 to immediately implement a four-squaring operation when the ground speed is less than or equal to the four-square speed threshold value.

[0062] In step 312, the controller 104 acts to command a downshift within the transmission 124. Typically, the transmission downshift operates to slow the vehicle 100, for example, to facilitate reaching a speed suitable for the squaring off. Upon completion of the transmission downshift, the method 300 proceeds to step 308, in which the vehicle speed is again evaluated in view of the squaring off speed threshold.

[0063] Returning to step 314, in response to the ground speed being less than or equal to the shuttle shift speed threshold, the controller 104 commands a shuttle shift within the transmission 124. As described above, the transmission shuttle shift occurs to change the direction of the vehicle 100 (e.g., from forward to reverse or from reverse to forward). The shuttle shift operates to slow the vehicle 100, for example, to facilitate reaching a speed suitable for the squaring off.

[0064] The method 300 proceeds from step 314 to step 316, in which the vehicle speed is evaluated to determine whether the vehicle is stopped. If the vehicle 100 is stopped, the method 300 proceeds to step 318 to engage the squaring off clutch, as described below. If the vehicle 100 is not stopped in step 316, the method 300 returns to step 314 to continue one or more shuttle shift operations.

[0065] If the vehicle is stopped from step 316 or the vehicle speed is otherwise suitable for squaring off clutch engagement from step 308, the method 300 proceeds to step 318. In step 318, the controller 104 selects one or more squaring off clutches in the transmission 124. The selected squaring off clutches can be a function of the current mode. For example, the selected squaring off clutches can be the same as the selected shuttle shift clutches in step 314. Figure 2 The clutches of the squaring off clutches in the transmission 124 depicted in FIG. 3 are provided in Table (1) above.

[0066] In step 320, the controller 104 generates a command to modulate the selected squaring off clutches. The selected squaring off clutches can be modulated as a function of a slope or gradient to implement a desired deceleration, examples of which are discussed below with reference to FIGS. 4-6. Figure 5 and Figure 6 As described above, the modulation of the selected squaring off clutches acts to slow the vehicle 100.

[0067] Upon modulating the squaring off clutches in step 320, the method 300 proceeds to step 322, in which the vehicle speed is evaluated to determine whether the vehicle 100 is stopped. If the vehicle 100 is still moving, the method 300 returns to step 320 to continue modulating the squaring off clutches to continue slowing the vehicle 100. If the vehicle 100 is stopped in step 322, the method 300 proceeds to step 324.

[0068] In step 324, the selected four-way clutch is fully engaged and remains engaged to maintain the stationary position of vehicle 100. See below for reference. Figure 5 and Figure 6 Exemplary implementations of engaging the four-way clutch and issuing commands to other clutches are discussed. Method 300 may terminate at this point to await further input or commands from the operator and / or controller 104.

[0069] You can refer to this. Figure 5 Additional details regarding the operation of the vehicle stop transmission control system 102 are provided. Figure 5 This is a diagram depicting the clutch command schedule 240, which reflects the relationship between clutch torque capacity, vehicle speed, and the time immediately before and during the vehicle's stop in transmission operation (e.g., such as...). Figure 4 (As discussed in steps 320, 322, and 324 of method 300). Additionally and briefly referenced Figure 3 The clutch command plan 240 can be implemented by the vehicle transmission stop module 112 of the controller 104.

[0070] exist Figure 5 In this diagram, the clutch torque capability is reflected on the first (or left) y-axis 242, the vehicle speed is reflected on the second (or right) y-axis 244, and time is reflected on the x-axis 246. Furthermore, the vehicle speed varying with time is represented by line 250; the input clutch torque capability varying with time is represented by line 252; the output clutch torque capability varying with time is represented by line 254; and the four-way clutch torque capability varying with time is represented by line 256. Generally, torque capabilities 252, 254, and 256 represent the engagement level of the corresponding clutch, for example, between zero engagement and maximum engagement. As described above, in Figure 5 In the example timetable depicted, the input clutch torque capacity 252, the output clutch torque capacity 254, and the four-way clutch torque capacity 256 are controlled by the controller 104 to make the vehicle speed 250 zero.

[0071] As shown, the input clutch torque capacity 252 and the output clutch torque capacity 254 are initially at their maximum values ​​during the initial time period, indicating that the vehicle 100 is operating normally in one of the modes described above. At the first time point 260, the controller 104 generates a stop command to initiate vehicle stop transmission operation. As described above and discussed in more detail below, the controller 104 generates the stop command for various reasons, including avoiding obstacles in the path of the vehicle 100 and / or parking on a slope.

[0072] When a stop command is generated at the first time point 260, the controller 104 commands the four-way clutches to prepare for engagement, for example by pressurizing the valves associated with the selected four-way clutches (e.g., clutches 190, 210 in the example above) for the current mode. Upon completion of preparation (represented by the second time point 262), the controller 104 at least partially disengages the input clutches (e.g., clutches 150, 152, 170, 172 in the example above). Additionally, at the second time point 262, the selected four-way clutches (e.g., clutches 190, 210) are at least partially engaged. As shown, the torque of the selected four-way clutches is initially zero and increases over time with a predetermined modulation slope. The predetermined modulation slope for the selected four-way clutches can be configured to produce a desired deceleration rate of the vehicle 100.

[0073] Initially at the second time point 262, in this example, the controller 104 commands the input clutch to partially disengage (but maintain a certain torque capacity) during the time period between the second time point 262 and the third time point 264. This partial torque capacity of the input clutch during this period provides a smoother transition when the vehicle stops operating the transmission. As reflected in the graph of vehicle speed 250 superimposed on the clutch command timetable 240, the engagement of the clutch results in a decrease in vehicle speed 250 at time point 262.

[0074] At the third time point 264, the input clutch torque capacity 252 decreases to zero. Furthermore, at the third time point 264, the four-way clutch torque capacity 256 continues to increase until it reaches the fourth time point 266, which coincides with the vehicle speed 250 reaching zero. At the fourth time point 266, the four-way clutch torque capacity 256 increases to its maximum value. In fact, at the fourth time point 266, the vehicle 100 comes to a complete stop, and the four-way clutch torque capacity 256 is reflected in the fully engaged four-way clutch that holds the vehicle 100 in a stationary position. As a result, the vehicle-stop transmission control system 102 exhibits [the following behavior / function] according to [the specified parameters]. Figure 5 The clutch command timetable 240 utilizes the transmission 124 as a mechanism to stop the vehicle 100.

[0075] It can provide other vehicles with the ability to stop their transmissions. Figure 6 The relationship between clutch current command (axis 272), vehicle speed (axis 274), and time (axis 276) reflects an additional clutch command timetable 270. Specifically, the clutch command timetable 270 depicts a vehicle speed 280 varying over time, an input clutch current command 282 varying over time, an output clutch current command 284 varying over time, and a four-way clutch current command 286 varying over time. (Brief Reference) Figure 3The clutch command timetable 270 can be implemented by the vehicle transmission stop module 112 of the controller 104.

[0076] As shown, the input clutch current command 282 and the output clutch current command 284 are initially at their maximum values ​​during the initial time period, indicating that the vehicle 100 is operating normally in one of the modes described above. At a first time point 290, the controller 104 generates a stop command to initiate vehicle stop transmission operation. When the stop command is generated at the first time point 290, the controller 104 commands the four-way clutch to prepare for engagement, for example, by providing a maximum current to the selected four-way clutch for a period of time, followed by a decrease in the current for partial engagement of the four-way clutch. When this preparation is complete (represented by the second time point 262), the input clutch is at least partially disengaged. Additionally, at the second time point 262, the clutch current command to the selected four-way clutch may be increased in a stepped and / or linear manner as part of a predetermined modulation slope, as shown, to produce the desired deceleration rate for the vehicle 100.

[0077] Initially at the second time point 292, in this example, the controller 104 commands the input clutch to partially disengage during the time period between the second time point 292 and the third time point 294 (but maintaining a certain torque capacity). This partial torque capacity of the input clutch during this period can provide a smoother transition when the transmission is stopped. Similarly, as shown by the vehicle speed 280 superimposed within the clutch command timetable 270, the partial engagement of the clutch causes the vehicle speed 280 to decrease at the second time point 292.

[0078] At the third time point 294, the input clutch current command 282 decreases to zero. Further, at the third time point 294, the four-way clutch current command 286 continues to increase until reaching the fourth time point 296, which coincides with the vehicle speed 280 decreasing to zero. At the fourth time point 296, the four-way clutch current command 286 increases to its maximum value. In effect, at the fourth time point 296, the vehicle 100 comes to a complete stop, and the four-way clutch torque capacity 256 reflects the fully engaged four-way clutch that brings the vehicle 100 to a stationary position. As a result, the clutch command schedule 270 implemented by the vehicle stop transmission control system 102 demonstrates the mechanism for stopping the vehicle 100 using the transmission 124.

[0079] Therefore, this disclosure provides a mechanism for stopping a vehicle with a transmission, particularly in autonomous situations, to avoid obstacles or perform ramp parking, thereby avoiding additional hardware that would otherwise be necessary to perform these functions using axles or service brakes.

[0080] In addition, the following examples are provided, which have been numbered for easy reference.

[0081] 1. A control system for a powertrain of an operating vehicle, the powertrain having a power source configured to generate power for an output shaft, the control system comprising:

[0082] A transmission, operably positioned between the power source and the output shaft, and configured to selectively transmit power from the power source to drive the output shaft in a first direction according to at least one forward mode, and to drive the output shaft in a second direction according to at least one reverse mode, the transmission comprising:

[0083] At least one forward input clutch, the at least one forward input clutch being configured to engage when power is transmitted in the at least one forward mode;

[0084] At least one reverse input clutch, the at least one reverse input clutch being configured to engage when transmitting power in the at least one reverse mode;

[0085] A first output clutch, configured to engage when transmitting power in a first mode of either the at least one forward mode or the at least one reverse mode; and

[0086] A second output clutch, configured to engage when transmitting power in a second mode of either the at least one forward mode or the at least one reverse mode; and

[0087] The controller, having a processor and memory architecture, is configured to:

[0088] Receive or generate a vehicle stop command;

[0089] Determine the ground speed of the operating vehicle;

[0090] The ground speed is compared with a first predetermined speed threshold and a second predetermined speed threshold;

[0091] When the ground speed exceeds the second predetermined speed threshold, at least one downshift command is generated for the transmission to perform a downshift within the transmission;

[0092] When the ground speed is greater than the first predetermined speed threshold and less than or equal to the second predetermined speed threshold, at least one shuttle shift command is generated for the transmission to perform a shuttle shift within the transmission.

[0093] When the ground speed is less than or equal to the first predetermined speed threshold, it is determined whether the transmission operates in the first mode or the second mode.

[0094] Once the operating mode is determined, a four-way clutch is selected from the first output clutch and the second output clutch, including selecting the second output clutch as the selected four-way clutch when the transmission is operating in the first mode, and selecting the first output clutch as the selected four-way clutch when the transmission is operating in the second mode; and

[0095] Engage the selected four-way clutch at least partially to slow down or stop the working vehicle.

[0096] 2. The control system according to Example 1, wherein the controller is further configured to: after the selected four-way clutch is at least partially engaged:

[0097] Assess the ground speed of the operating vehicle; and

[0098] When the speed of the work vehicle is approximately zero, the selected four-way clutch is fully engaged.

[0099] 3. The control system according to Example 2, wherein the controller is further configured to, when performing a downshift:

[0100] The ground speed is compared with the first predetermined speed threshold and the second predetermined speed threshold;

[0101] When the ground speed exceeds the second predetermined speed threshold, an additional downshift command is generated for the transmission to perform further downshifting within the transmission;

[0102] When the ground speed is greater than the first predetermined speed threshold and less than or equal to the second predetermined speed threshold, at least one shuttle shift command is generated for the transmission to perform the shuttle shift within the transmission.

[0103] When the ground speed is less than or equal to the first predetermined speed threshold, it is determined whether the transmission operates in the first mode or the second mode.

[0104] Once the operating mode is determined, the four-way clutch is selected from the first output clutch and the second output clutch, including selecting the second output clutch as the selected four-way clutch when the transmission is operating in the first mode, and selecting the first output clutch as the selected four-way clutch when the transmission is operating in the second mode; and

[0105] Engage the selected four-way clutch at least partially to slow down the work vehicle.

[0106] 4. The control system according to Example 1, wherein the controller is further configured to, when performing the shuttle shift:

[0107] Assess the ground speed of the operating vehicle; and

[0108] When the speed of the work vehicle is approximately zero, the selected four-way clutch is fully engaged.

[0109] 5. The control system according to Example 1, wherein the controller is further configured to:

[0110] Receive sensor data from at least one sensor on the work vehicle;

[0111] The sensor data is evaluated to identify the vehicle's stopping status; and

[0112] When the vehicle's stopping status is identified as stopping the work vehicle, a vehicle stop command is generated.

[0113] 6. The control system according to Example 5, wherein the sensor data is obstacle data, and wherein the controller is further configured to:

[0114] The obstacle data is evaluated to identify the vehicle's stopped state as an obstacle in the path of the operating vehicle; and

[0115] When the obstacle is in the path of the work vehicle, a vehicle stop command is generated.

[0116] 7. The control system according to Example 5, wherein the sensor data is tilt data, and wherein the controller is further configured to:

[0117] Assess obstacle data to identify the vehicle's stopping condition as a ramp parking condition; and

[0118] Once the parking status on the ramp is identified, a stop command for the work vehicle is generated.

[0119] 8. The control system according to Example 1, wherein the controller is further configured to partially disengage the at least one forward input clutch or the at least one reverse input clutch once the selected four-way clutch is at least partially engaged.

[0120] 9. The control system according to Example 1, wherein the controller is further configured to fully disengage the at least one forward input clutch or the at least one reverse input clutch and fully engage the selected four-way clutch when the ground speed reaches zero.

[0121] 10. The control system according to Example 9, wherein the controller is configured to maintain engagement of the first output clutch during operation in the first mode when the selected four-way clutch is at least partially engaged, and to maintain engagement of the second output clutch during operation in the second mode when the selected four-way clutch is at least partially engaged.

[0122] 11. The control system according to Example 10, wherein the controller is configured to maintain engagement of the first output clutch during operation in the first mode when the selected four-way clutch is fully engaged and the ground speed reaches zero, and to maintain engagement of the second output clutch during operation in the second mode when the selected four-way clutch is fully engaged and the ground speed reaches zero.

[0123] 12. A method of operating a powertrain of a work vehicle, the powertrain comprising: a power source configured to generate power for an output shaft; a transmission operably positioned between the power source and the output shaft, and the transmission configured to selectively transmit power from the power source to drive the output shaft in a first direction according to at least one forward mode, and to drive the output shaft in a second direction according to at least one reverse mode, the transmission comprising: at least one forward input clutch configured to engage when transmitting power in the at least one forward mode; and at least one reverse input clutch configured to engage when transmitting power in the at least one reverse mode; a first output clutch configured to engage when transmitting the power in the first mode of the at least one forward mode or the at least one reverse mode; and a second output clutch configured to engage when transmitting the power in the second mode of the at least one forward mode or the at least one reverse mode, the method comprising:

[0124] Receive or generate a vehicle stop command for slowing down and stopping the work vehicle;

[0125] The ground speed of the work vehicle is determined using a controller on the work vehicle;

[0126] The controller compares the ground speed with a first predetermined speed threshold and a second predetermined speed threshold;

[0127] When the ground speed exceeds the second predetermined speed threshold, the controller generates at least one downshift command for the transmission to perform a downshift within the transmission.

[0128] When the ground speed is greater than the first predetermined speed threshold and less than or equal to the second predetermined speed threshold, the controller generates at least one shuttle shift command for the transmission to perform a shuttle shift within the transmission.

[0129] When the ground speed is less than or equal to the first predetermined speed threshold, the controller determines whether the transmission operates in the first mode or the second mode.

[0130] Once the operating mode is determined, the controller selects a four-way clutch from the first and second output clutches, including selecting the second output clutch as the selected four-way clutch when the transmission is operating in the first mode, and selecting the first output clutch as the selected four-way clutch when the transmission is operating in the second mode; and

[0131] Engage the selected four-way clutch at least partially to slow down the work vehicle.

[0132] 13. The method according to Example 12 further includes: after the selected four-way clutch is at least partially engaged:

[0133] Assess the ground speed of the operating vehicle; and

[0134] When the speed of the work vehicle is approximately zero, the selected four-way clutch is fully engaged.

[0135] 14. The method according to Example 13 further includes, when performing the downshift:

[0136] The ground speed is compared with the first predetermined speed threshold and the second predetermined speed threshold;

[0137] When the ground speed exceeds the second predetermined speed threshold, an additional downshift command is generated for the transmission to perform further downshifting within the transmission;

[0138] When the ground speed is greater than the first predetermined speed threshold and less than or equal to the second predetermined speed threshold, at least one shuttle shift command is generated for the transmission to perform the shuttle shift within the transmission.

[0139] When the ground speed is less than or equal to the first predetermined speed threshold, it is determined whether the transmission operates in the first mode or the second mode.

[0140] Once the operating mode is determined, the four-way clutch is selected from the first output clutch and the second output clutch, including selecting the second output clutch as the selected four-way clutch when the transmission is operating in the first mode, and selecting the first output clutch as the selected four-way clutch when the transmission is operating in the second mode; and

[0141] Engage the selected four-way clutch at least partially to slow down or stop the working vehicle.

[0142] 15. The method according to Example 12 further includes, when performing the shuttle shift:

[0143] Assess the ground speed of the operating vehicle; and

[0144] When the speed of the work vehicle is approximately zero, the selected four-way clutch is fully engaged.

[0145] As used herein, "direct" or "directly" can be used to indicate the transfer of power between two system components without an intermediate conversion of power to another form. For example, if power is transmitted via multiple shafts, clutches, and gears (e.g., various spur gears, bevel gears, accumulator gears, or other gears) without being converted to a different form by a CVP (e.g., without being converted to electric or hydraulic power by a generator or hydraulic pump), then power can be considered to be transferred "directly" from the engine to the output component. In some configurations, the fluid transmission of rotational power via a torque converter can also be considered "direct." In contrast, if a portion of the power is converted to another form during transmission, then power cannot be considered to be transferred "directly" between the two system components. For example, if a portion of the engine's power is converted to a different form by a CVP, even if that portion is later converted back to rotational power (e.g., via another CVP) and then recombined with the unconverted engine power (e.g., via accumulator planetary gears or other accumulator components), power cannot be considered to be transferred "directly" between the engine and the output component. Moreover, as used herein, “between” can be used to refer to a specific order or sequence of power transmission components, rather than to the physical orientation or placement of the components. For example, if power is routed to the output component via a clutch device, the clutch device can be considered to be “between” the engine and the output component, regardless of whether the engine and the output component are on physically opposite sides of the clutch device.

[0146] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this 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 should also be understood that, when used in this specification, the term “comprises and / or comprising” specifies the presence of stated features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0147] As those skilled in the art will understand, certain aspects of the disclosed subject matter can be implemented as a method, system (e.g., a work vehicle control system included in a work vehicle), or computer program product. Therefore, some embodiments can be implemented entirely as hardware, entirely as software (including firmware, resident software, microcode, etc.), or as a combination of software and hardware (and other aspects). Additionally, some embodiments can take the form of a computer program product on a computer-usable storage medium having computer-usable program code contained therein.

[0148] Any suitable computer-usable or computer-readable medium may be used. A 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 computing devices or client electronic devices) may be, for example, but not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatuses, or devices, or any suitable combination thereof. More specific examples (not an exhaustive list) of computer-readable media will include the following: electrical connections having one or more wires, portable computer disks, hard disks, random-access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, compact disc read-only memory (CD-ROM), and optical storage devices. In the context of this document, a computer-usable or computer-readable storage medium may be any tangible medium capable of containing or storing programs used by or in conjunction with an instruction execution system, apparatus, or device.

[0149] Computer-readable signal media may include propagated data signals in which computer-readable program code is implemented, such as in baseband or as part of a carrier wave. Such propagated signals may take any of a variety of forms, including, but not limited to, electromagnetic, optical, or any suitable combination thereof. Computer-readable signal media may be non-transitory and may not be computer-readable storage media; any computer-readable medium may communicatively transmit, propagate, or deliver a program used by or in conjunction with an instruction execution system, apparatus, or device.

[0150] 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 this disclosure. It should be understood that each block of any such flowchart illustration and / or block diagram, and combinations of blocks in such flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can 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 / actions specified in one or more blocks of the flowchart illustration and / or block diagram.

[0151] These computer program instructions may also be stored in a computer-readable storage medium that can instruct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of writing which includes instructions that implement the functions / actions specified in one or more boxes of a flowchart and / or block diagram.

[0152] 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, thereby producing a computer-implemented process, such that the instructions, which execute on the computer or other programmable apparatus, provide steps for implementing the functions / actions specified in one or more boxes of a flowchart and / or block diagram.

[0153] Any flowcharts and block diagrams in the accompanying drawings, 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 this disclosure. In this regard, each block in a flowchart or block diagram may represent a module, code segment, or code portion comprising one or more executable instructions for implementing the specified logical function(s). It should also be noted that in some alternative implementations, the functions described in the blocks (or otherwise described herein) may occur in a non-sequential order as depicted in the drawings. For example, two blocks shown consecutively (or two operations described consecutively) may actually be executed substantially simultaneously, or these blocks (or operations) may sometimes be executed in reverse order, depending on the functions involved. It will also be noted that each block in any block diagram and / or flowchart illustration, and any combination of blocks in any block diagram and / or flowchart illustration, may be implemented by a system based on dedicated hardware or by a combination of dedicated hardware and computer instructions that performs the specified function or action.

[0154] The description in this disclosure has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the disclosure presented in its form. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of this disclosure. The embodiments expressly referenced herein were chosen and described in order to best explain the principles of this disclosure and its practical application, and to enable others skilled in the art to understand the contents of this disclosure and recognize the many alternatives, modifications, and variations of the described examples(s). Therefore, various embodiments and implementations other than those expressly described are within the scope of the following claims.

Claims

1. A control system (102) for operating a powertrain (106) of a work vehicle (100), the powertrain having a power source (122) configured to generate power for an output shaft (232), the control system (102) comprising: a transmission (124) operably positioned between the power source (122) and the output shaft (232) and configured to selectively transfer power from the power source (122) to drive the output shaft (232) in a first direction according to at least one forward mode and to drive the output shaft in a second direction according to at least one reverse mode, the transmission (124) including: at least one forward input clutch (150, 152) configured to be engaged when transferring power in the at least one forward mode; at least one reverse input clutch (170, 172) configured to be engaged when transferring power in the at least one reverse mode; a first output clutch configured to be engaged when transferring the power in a first one of the at least one forward mode or the at least one reverse mode; and a second output clutch configured to be engaged when transferring the power in a second one of the at least one forward mode or the at least one reverse mode; and a controller (104) having a processor (114) and memory (116) architecture, the controller configured to: receive or generate a vehicle stop command; determine a ground speed of the work vehicle (100); compare the ground speed to a first predetermined speed threshold and a second predetermined speed threshold; generate at least one downshift command for the transmission (124) to perform a downshift within the transmission (124) when the ground speed exceeds the second predetermined speed threshold; generate at least one shuttle shift command for the transmission (124) to perform a shuttle shift within the transmission (124) when the ground speed is greater than the first predetermined speed threshold and less than or equal to the second predetermined speed threshold; determine whether the transmission (124) is operating in the first mode or the second mode as an operating mode when the ground speed is less than or equal to the first predetermined speed threshold; select a four-square clutch from the first output clutch and the second output clutch once the operating mode is determined, including selecting the second output clutch as the selected four-square clutch when the transmission (124) is operating in the first mode and selecting the first output clutch as the selected four-square clutch when the transmission (124) is operating in the second mode; and engaging the selected four-square clutch at least partially to slow or stop the work vehicle (100).

2. The control system (102) of claim 1, wherein, The controller (104) is further configured to, after the selected four-square clutch is engaged at least partially: evaluate a ground speed of the work vehicle (100); and fully engage the selected four-square clutch when the speed of the work vehicle (100) is approximately zero.

3. The control system (102) of claim 2, wherein, The controller (104) is further configured to, when performing the downshift: compare the ground speed to the first predetermined speed threshold and the second predetermined speed threshold; generate a further downshift command for the transmission (124) to perform a further downshift within the transmission (124) when the ground speed exceeds the second predetermined speed threshold; generate the at least one shuttle shift command for the transmission (124) to perform the shuttle shift within the transmission (124) when the ground speed is greater than the first predetermined speed threshold and less than or equal to the second predetermined speed threshold; determine whether the transmission (124) is operating in the first mode or the second mode as an operating mode when the ground speed is less than or equal to the first predetermined speed threshold; select the four-square clutch from the first output clutch and the second output clutch once the operating mode is determined, including selecting the second output clutch as the selected four-square clutch when the transmission (124) is operating in the first mode and selecting the first output clutch as the selected four-square clutch when the transmission (124) is operating in the second mode; and engage the selected four-square clutch at least partially to slow the work vehicle (100).

4. The control system (102) of claim 1, wherein, The controller (104) is further configured to, when performing the shuttle shift: evaluate a ground speed of the work vehicle (100); and fully engage the selected four-square clutch when the speed of the work vehicle (100) is approximately zero.

5. The control system (102) of claim 1, wherein, The controller (104) is further configured to: receive sensor data from at least one sensor (108) on the work vehicle (100); evaluate the sensor data to identify a vehicle stop condition; and generate the vehicle stop command when the vehicle stop condition is identified as stopping the work vehicle (100).

6. The control system (102) of claim 5, wherein, The sensor data is obstacle data, and wherein the controller (104) is further configured to: evaluate the obstacle data to identify the vehicle stop condition as an obstacle in a path of the work vehicle (100); and generate the vehicle stop command when the obstacle is in the path of the work vehicle (100).

7. The control system (102) of claim 5, wherein, The sensor data is incline data, and wherein the controller (104) is further configured to: evaluate obstacle data to identify the vehicle stop condition as a hill park condition; and generate the work vehicle stop command once the hill park condition is identified.

8. The control system (102) of claim 1, wherein, The controller (104) is further configured to, once causing the selected four-square clutch to be at least partially engaged, cause the at least one forward input clutch (150, 152) or the at least one reverse input clutch (170, 172) to be partially disengaged.

9. The control system (102) of claim 1, wherein, The controller (104) is further configured to, when the ground speed reaches zero, cause the at least one forward input clutch (150, 152) or the at least one reverse input clutch (170, 172) to be fully disengaged and cause the selected four-square clutch to be fully engaged.

10. The control system (102) of claim 9, wherein, The controller (104) is configured to, during operation in the first mode, maintain engagement of the first output clutch when causing the selected four-square clutch to be at least partially engaged, and during operation in the second mode, maintain engagement of the second output clutch when causing the selected four-square clutch to be at least partially engaged.

11. The control system (102) of claim 10, wherein, The controller (104) is configured to, during operation in the first mode, maintain engagement of the first output clutch when causing the selected four-square clutch to be fully engaged and the ground speed to reach zero, and during operation in the second mode, maintain engagement of the second output clutch when causing the selected four-square clutch to be fully engaged and the ground speed to reach zero.

12. A method (300) of operating a powertrain (106) of a work vehicle (100), the powertrain having a power source (122) configured to generate power for an output shaft (232), a transmission (124) operably positioned between the power source (122) and the output shaft (232) and configured to selectively transfer power from the power source (122) to drive the output shaft (232) in a first direction according to at least one forward mode and in a second direction according to at least one reverse mode, the transmission (124) comprising: at least one forward input clutch (150, 152) configured to be engaged when power is being transferred in the at least one forward mode; and at least one reverse input clutch (170, 172) configured to be engaged when power is being transferred in the at least one reverse mode; a first output clutch configured to be engaged when the power is being transferred in a first one of the at least one forward mode or the at least one reverse mode; and a second output clutch configured to be engaged when the power is being transferred in a second one of the at least one forward mode or the at least one reverse mode, the method comprising: receiving or generating a vehicle stop command for slowing and stopping the work vehicle (100); determining, with a controller (104) on the work vehicle (100), a ground speed of the work vehicle (100); comparing, by the controller (104), the ground speed to a first predetermined speed threshold and a second predetermined speed threshold; generating, by the controller (104), at least one downshift command for the transmission (124) to perform a downshift within the transmission (124) when the ground speed exceeds the second predetermined speed threshold; generating, by the controller (104), at least one shuttle shift command for the transmission (124) to perform a shuttle shift within the transmission (124) when the ground speed is greater than the first predetermined speed threshold and less than or equal to the second predetermined speed threshold; determining, by the controller (104), whether the transmission (124) is operating in the first mode or the second mode as an operating mode when the ground speed is less than or equal to the first predetermined speed threshold; selecting, by the controller (104), the four-way clutch from the first output clutch and the second output clutch once the operating mode is determined, including selecting the second output clutch as the selected four-way clutch when the transmission (124) is operating in the first mode and selecting the first output clutch as the selected four-way clutch when the transmission (124) is operating in the second mode; and causing the selected four-way clutch to at least partially engage to slow the work vehicle (100).

13. The method (300) of claim 12, further comprising: after the selected four-way clutch is at least partially engaged: evaluating a ground speed of the work vehicle (100); and causing the selected four-way clutch to fully engage when the speed of the work vehicle (100) is approximately zero.

14. The method (300) of claim 13, further comprising, while performing the downshift: comparing the ground speed to the first predetermined speed threshold and the second predetermined speed threshold; generating a further downshift command for the transmission (124) to perform a further downshift within the transmission (124) when the ground speed exceeds the second predetermined speed threshold; generating the at least one shuttle shift command for the transmission (124) to perform the shuttle shift within the transmission (124) when the ground speed is greater than the first predetermined speed threshold and less than or equal to the second predetermined speed threshold; determining whether the transmission (124) is operating in the first mode or the second mode as an operating mode when the ground speed is less than or equal to the first predetermined speed threshold; selecting the four-way clutch from the first output clutch and the second output clutch once the operating mode is determined, including selecting the second output clutch as the selected four-way clutch when the transmission (124) is operating in the first mode and selecting the first output clutch as the selected four-way clutch when the transmission (124) is operating in the second mode; and causing the selected four-way clutch to at least partially engage to slow or stop the work vehicle (100).

15. The method (300) of claim 12, further comprising, while performing the shuttle shift: evaluating a ground speed of the work vehicle (100); and causing the selected four-way clutch to fully engage when the speed of the work vehicle (100) is approximately zero.

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