Patent Application
20250050889
The present disclosure relates to a transmission that includes power take-off ports for driving loads that may be coupled directly to a vehicle powertrain via gears. The loads may include loads that are driven while the vehicle is traveling.
A vehicle may include a transmission that includes an output shaft that is coupled to vehicle wheels and a power take-off that is coupled to an output shaft of the transmission via a planetary gear set. The power take-off may transfer torque from an internal combustion engine, or other power source (e.g., an electric machine, fuel cell, etc.), to a device that is coupled to a transmission but does not aid in motion of the vehicle. For example, the power take-off may provide mechanical power to a pump that supplies pressurized fluid to a pump in a hydraulic circuit. The power take-off may rotate at a requested speed when the vehicle is stationary and not traveling on a road with its wheels rotating. The requested speed may be based on the device that is coupled to the power take-off. However, if the vehicle is traveling on a road with its wheels rotating, the power take-off may be deactivated (e.g., adjusted to zero rotational speed) because maintaining a requested wheel torque may be difficult when load on the power take-off changes. For example, because torque at the transmission output shaft and torque at the power take-off output are coupled, it may be possible to provide torque to the transmission output shaft or the power take-off in an unintended rotational direction and/or at an unintended rate of speed change. Further, driving while the wheels and power take-off are engaged may lead to a vehicle's human driver having to learn unnatural driving behaviors to operate the vehicle in an intended way. While it may be possible to dynamically estimate torque that is delivered to the power take-off and the vehicle's wheels, or to estimate torque at an input shaft of the transmission and a power take-off that is coupled to the input shaft of the transmission, generating these estimates may be financial prohibitive. In addition, the system complexity may be greater and there may be greater possibility of sensor degradation. Therefore, it may be desirable to provide a way of controlling a power take-off output and transmission shaft output in a way that reduces the possibility of unintended directional rotation without having to accurately estimate torque at the transmission output shaft and the power take-off.
The inventors herein have recognized the above-mentioned issues and have developed a powertrain, comprising: a transmission including a power take-off and an output shaft that delivers torque to vehicle wheels, where the power take-off is coupled to the output shaft via a planetary gear set; and a controller including executable instructions that cause the controller to operate the powertrain in a first speed control mode where a speed of the output shaft is controlled via the controller in response to a vehicle that includes the powertrain traveling with rotating wheels while delivering power to the power take-off.
By operating the powertrain in a speed control mode where vehicle speed is controlled while a vehicle is moving and a power take-off of the vehicle is activated, it may be possible to avoid unintended movement of the vehicle and operate the power take-off device. Further, it may be possible to avoid additional financial expenses of estimating torque at various locations along the powertrain. In particular, since a speed controller uses feedback of vehicle speed instead of an estimated torque at a particular location along the driveline, the vehicle may be controlled with a readily available speed feedback signal without having to estimate torque at the transmission output shaft and at the power take-off.
The present description may provide several advantages. In particular, the approach may increase powertrain functionality by allowing a vehicle that includes a second power take-off to operate in a desired way when a vehicle is moving. In addition, the approach may reduce a possibility of a vehicle traveling in an unintended direction and unintended rates of speed change for a vehicle. Further, the approach may allow a vehicle operator to operate the vehicle in a natural or expected way.
It may be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not constrained to implementations that solve any disadvantages noted above or in any part of this disclosure.
The accompanying drawings are incorporated herein as part of the specification. The drawings described herein illustrate embodiments of the presently disclosed subject matter, and are illustrative of selected principles and teachings of the present disclosure. However, the drawings do not illustrate all possible implementations of the presently disclosed subject matter, and are not intended to constrain the scope of the present disclosure in any way.
The following description relates to systems and methods for operating a moving vehicle that includes a power take-off device to drive external loads. The vehicle may include a transmission with two power take-off ports that may be driven via an external power source or via an electric machine that is included in the transmission. The transmission may be included in a two or four wheel drive vehicle as shown in
Electric energy storage device 16 (e.g., a traction battery or capacitor) may provide electric power to electric machines included in transmission 14. Transmission 14 may supply mechanical power to mechanically driven accessories 18 and 20. Transmission 14 may be operated via controller 15. In this example, controller 15 is configured to command electric machines (not shown), clutches (not shown), and brakes (not shown) within transmission 14. Controller 15 may switch operating modes of transmission 14 via adjusting states of clutches and brakes as indicated in
Referring now to
Turning now to
Connecting shaft 304 may be selectively coupled to electric machine 208 and sun gear 306 of third planetary gear set PT3 via closing input coupled clutch C1. Sun gear 306 of third planetary gear set PT3 is coupled to planetary gears 308. Planetary gears 308 are coupled to ring gear 310, and planetary gears 308 are supported via carrier 312. Planetary gears 308 are coupled to ring gear 318 of second planetary gear set PT2 and planetary gears 316 of first planetary gear set PT1 via carrier 312 of third planetary gear set PT3 and carrier 328 of first planetary gear set PT1. Carrier 328 of first planetary gear set PT1 is coupled to wheels 103 via transmission output shaft 130. Brake B1 may be closed to ground or couple ring gear 310 of third planetary gear set PT3 to transmission housing 399.
Second planetary gear set PT2 includes a sun gear 314 that is coupled to ring gear 310 of first planetary gear set PT1. Planetary gears 308 of second planetary gear set PT2 are coupled to sun gear 314 of planetary gear set PT2 and ring gear 318 of second planetary gear set PT2. Brake B2 may be closed to ground or couple carrier 320 of second planetary gear set PT2 to transmission housing 399.
PTO 1 is directly coupled to connecting shaft 304. Therefore, whenever connecting shaft 304 is rotating, PTO 1 output shaft 362 rotates. PTO 1 output shaft 362 may be rotated via closing clutch C0 when propulsion source 12 is rotating. PTO 1 may also be rotated via electric machine 208 by closing clutch C1. PTO 1 may rotate in any of the modes that are shown in the table of
PTO 2 may rotate and provide mechanical power to accessories 20 during three modes as indicated in
PTO 2 output shaft 342 may be rotated when clutch C1 is open, C2 is closed, and C0 is open or closed. PTO 2 output shaft 342 may also provide mechanical torque to accessories 20 when brake B1 is open, B2 is closed, C1 is open, C2 is closed and C0 is open or closed. Applying brake B2 prevents rotation of carrier 320 so that when propulsion source 12 or electric machine 208 drive the transmission output shaft 130 via connecting shaft 304, second planetary gear set PT2, and first planetary gear set PT1, PTO 2 gear 340 may rotate. Energy may flow from propulsion source 12 to connecting shaft 304 via clutch C0, connecting shaft 304 may transfer torque to ring gear 326 causing planetary gears 316 to rotate along with sun gear 322 so that carrier 328 and transmission output shaft 130 may rotate. Rotating sun gear 322 allows PTO 2 gear 340 to rotate. PTO2 output shaft 342 may rotate when clutch C2 is closed.
PTO 2 output shaft 342 may also be rotated when clutch C1 is open, C2 is closed, and C0 is open or closed. PTO 2 output shaft 342 may also provide mechanical torque to accessories 20 when brake B1 is closed, B2 is open, C1 is open, C2 is closed and C0 is open or closed. Applying brake B1 prevents rotation of ring gear 310 and sun gear 306. Energy may flow from propulsion source 12 to connecting shaft 304 via clutch C0, connecting shaft 304 may transfer torque to ring gear 326 causing planetary gears 316 to rotate along with sun gear 322 so that carrier 328 and transmission output shaft 130 may rotate. Rotating sun gear 322 allows PTO 2 gear 340 to rotate. PTO2 output shaft 342 may rotate when clutch C2 is closed.
Thus the system of
Thus, the system of
Referring now to
The vehicle speed controller 402 may receive input via a driver demand pedal 100 and a brake pedal. The driver demand pedal position and the brake pedal position are input to block 418. Block 418 converts the brake pedal position and driver demand pedal position in a requested vehicle speed. In one example, block 418 may include a function or table 419 that is referenced or indexed via driver demand pedal position and brake pedal position. The function or table outputs an empirically determined requested vehicle speed. The requested vehicle speed values may be determined via applying the driver demand pedal and brake pedal and adjusting the requested vehicle speed until vehicle performance objectives are met. The requested vehicle speed is input to block 416.
Block 416 represents a vehicle speed controller. In one example, the vehicle speed controller is a proportional/integral/derivative (PID) controller as described in
At block 414, the requested wheel torque may be constrained to be within an upper torque threshold and a lower torque threshold via a filter as shown in
Blocks 420 and 422 are optional as indicated by the dashed lines. If block 420 is present, it receives input of driver demand pedal position and brake pedal position. A table or function 421 may be referenced or indexed via driver demand pedal position and brake pedal position. The table or function 421 outputs a requested wheel torque and the requested wheel torque is input to block 422.
If block 422 is present, the powertrain 119 may be operated in torque control mode or in vehicle speed control mode. If human driver 109 requests operation of PTO 2 and the vehicle is traveling with its wheels rotating, block 422 may switch such that the filtered wheel torque output from block 414 is commanded of the powertrain 119. On the other hand, if human driver 109 is not requesting operation of PTO 2, block 422 may switch such that requested wheel torque output from block 420 is commanded of the powertrain 119. If block 422 is not present, the filtered requested vehicle speed is directly commanded of the powertrain 119. Additionally, if block 422 is not present, the vehicle may operate solely in vehicle speed control mode. Powertrain 119 may adjust torque output of one or more propulsion sources (e.g., electric machine or internal combustion engine) to generate the torque that produces the requested vehicle speed, wheel torque, and PTO speed.
In addition to vehicle speed controller 402, a speed controller 403 for PTO 2 is included to control the rotational speed of PTO 2. Human driver 109 may request a rotational speed for PTO 2 via human/machine interface 404. The human/machine interface may output a requested rotational speed for PTO 2 to block 406.
Block 406 represents a PTO rotational speed controller for PTO 2. In one example, the vehicle speed controller is a proportional/integral/derivative (PID) controller similar to the speed controller that is described in
At block 408, the requested rotational PTO 2 speed may be constrained to be within an upper torque threshold and a lower torque threshold via a filter. The output of block 408 is a filtered requested rotational PTO 2 speed and the powertrain 119 may be commanded to the filtered requested rotational PTO 2 speed. The powertrain 119 may respond to the filtered requested rotational PTO 2 speed via generating PTO 2 via a propulsion source of the powertrain 119. The rotational PTO 2 speed is fed back to block 406 where it is applied to correct the requested rotational PTO 2 speed. The filtered requested rotational PTO 2 speed is commanded of the powertrain 119. Powertrain 119 may rotate accessories 20 (e.g., a pump) at the requested rotational PTO 2 speed.
Thus, the control block diagram of
In another representation, the method of
Referring now to
Solid line 502 represents an upper torque threshold that is not to be exceeded by wheel torque when operating the powertrain with PTO 2 active and the vehicle traveling with its wheels rotating. Dashed line 504 represents a negative torque threshold with a magnitude that is not to be exceeded by wheel torque when operating the powertrain with PTO 2 active and the vehicle traveling with its wheels rotating. Thus, the allowable range for wheel torque is between threshold 502 and threshold 504. The commanded or final wheel torque may vary between the thresholds (502 and 504), but its magnitude is constrained not to be in the area that is above threshold 502 and constrained not to be in the area that is below threshold 504.
The vehicle speeds between vertical line 550 and vertical line 551 represent a range where wheel torque increases as a magnitude of negative vehicle speed (e.g., travel in reverse) decreases. The vehicle speeds between vertical line 552 and vertical line 553 represent a range where wheel torque decreases as a magnitude of positive vehicle speed (e.g., travel in a forward direction) increases.
Thus, it may be observed that for lower vehicle speeds, larger amounts of wheel torque may be generated via the powertrain in forward (positive) and reverse (negative) directions. This allows for a low requested vehicle speed (e.g., zero) via adjusting vehicle brakes while PTO 2 is active. At higher vehicle speeds, regenerative braking torque is constrained to a small value such that when actual vehicle speed is greater than the requested vehicle speed, the vehicle coasts (e.g., moves without sending powertrain torque to the wheels).
Turning now to
At summing junction 606, actual or measured vehicle speed is subtracted from a requested vehicle speed to generate a vehicle speed error. The vehicle speed error is delivered to blocks 608-612. At block 608, a proportional scalar or gain (e.g., a real number) variable Kp is multiplied by the vehicle speed error (e) that is a function of time to generate a proportional component of the PID controller output. Block 608 outputs the proportional component of the PID controller to summing junction 614. At block 610, an integral scalar or gain (e.g., a real number) variable Ki is multiplied by the integral of the vehicle speed error (e) to generate an integral component of the PID controller output. Block 610 outputs the integral component of the PID controller to summing junction 614. At block 612, a derivative scalar or gain (e.g., a real number) variable Kd is multiplied by the derivative of vehicle speed error (e) to generate a derivative component of the PID controller output. Block 612 outputs the proportional component of the PID controller to summing junction 614. The PID control adjustment to generator torque is output from summing junction 614 to the powertrain 119 (not shown).
Note that the example control and estimation routines included herein can be used with various powertrain and/or vehicle system configurations. The control methods and routines disclosed herein may be stored as executable instructions in non-transitory memory and may be carried out by the control system including the controller in combination with the various sensors, actuators, and other engine hardware. Further, portions of the methods may be physical actions taken in the real world to change a state of a device. The specific routines described herein may represent one or more of any number of processing strategies such as event-driven, interrupt-driven, multi-tasking, multi-threading, and the like. As such, various actions, operations, and/or functions illustrated may be performed in the sequence illustrated, in parallel, or in some cases omitted. Likewise, the order of processing is not necessarily required to achieve the features and advantages of the examples described herein, but is provided for case of illustration and description. One or more of the illustrated actions, operations and/or functions may be repeatedly performed depending on the particular strategy being used. Further, the described actions, operations and/or functions may graphically represent code to be programmed into non-transitory memory of the computer readable storage medium in the engine control system, where the described actions are carried out by executing the instructions in a system including the various engine hardware components in combination with the electronic controller. One or more of the method steps described herein may be omitted if desired.
It will be appreciated that the configurations and routines disclosed herein are exemplary in nature, and that these specific examples are not to be considered in a constrained sense, because numerous variations are possible. For example, the above technology can be applied to powertrains that include different types of propulsion sources including different types of electric machines and transmissions. The subject matter of the present disclosure includes all novel and non-obvious combinations and sub-combinations of the various systems and configurations, and other features, functions, and/or properties disclosed herein.
The following claims particularly point out certain combinations and sub-combinations regarded as novel and non-obvious. These claims may refer to “an” element or “a first” element or the equivalent thereof. Such claims may be understood to include incorporation of one or more such elements, neither requiring nor excluding two or more such elements. Other combinations and sub-combinations of the disclosed features, functions, elements, and/or properties may be claimed through amendment of the present claims or through presentation of new claims in this or a related application. Such claims, whether broader, narrower, equal, or different in scope to the original claims, also are regarded as included within the subject matter of the present disclosure.
The present application claims priority to U.S. Provisional Application No. 63/518,316, entitled “CONTROL OF TRANSMISSION WITH ACTIVATED POWER TAKE-OFF”, and filed on Aug. 8, 2023. The entire contents of the above-listed application are hereby incorporated by reference for all purposes.
| Number | Date | Country | |
|---|---|---|---|
| 63518316 | Aug 2023 | US |
