The present disclosure relates to a vehicle system that includes implement controls with propulsion controls.
A vehicle may include one or more implement controls that provide power to devices that do not operate to propel the vehicle. For example, a vehicle may include implement controls for adjusting boom angle, bucket angle, and an extension distance of a telescopic boom. These implement controls may include one or more hydraulic valves and a hydraulic pump that provides motive force to hydraulic fluid. The hydraulic pump may supply pressurized hydraulic fluid to actuators and hydraulic cylinders that may adjust operation of each of the implements according to input to a human machine interface (e.g., a joystick) by a vehicle operator. The vehicle operator may request that power be delivered to more than one of the implements simultaneously, and there may be instances when it may be possible for the operator to request power to operate implements that may be sufficient to stall an engine that provides torque to rotate the hydraulic pump. In addition, the power that the vehicle operator requests through the human machine interface to control the implements may be in addition to a power request to propel the vehicle. Therefore, it may be possible for operation of implements to affect power that is applied to propel the vehicle.
To address at least a portion of the abovementioned issues, the inventors herein have developed a vehicle system. The vehicle system includes a human/machine interface; a plurality of implement actuators; and a controller including instructions stored in non-transitory memory that when executed cause the controller to adjust an amount of power delivered to one or more of the plurality of implement actuators in response to an amount of power requested to operate the plurality of implement actuators as requested via input to the human/machine interface.
By adjusting the amount of power that is delivered to one or more of the plurality of implement actuators in response to an amount of power that is requested to operate the plurality of implement actuators as requested via input to the human/machine interface, it may be possible to provide the technical result of limiting power to operate implements so that an engine may not become overloaded. Further, in some examples, the amount of power that is delivered to the one or more of the plurality of implement actuators may be limited in response to a transmission power request so that vehicle propulsion maybe maintained even if implement use is requested at a same time as vehicle propulsion is requested.
The present description may provide several advantages. In particular, the approach may reduce a possibility of engine stalling. Further, the approach allows for a priority of operating implements to be assigned by a power manager so that operation of select vehicle functions may be maintained. In addition, the approach may provide additional functionality without increasing system hardware cost.
It is to be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.
A method and system for regulating power delivery to implements of a propelled vehicle is described herein. The method and system may allocate power delivery to implements as a function of requested power for propulsive effort so that propulsive effort may be maintained while operation of implements is requested. Power delivery to the vehicle's implements may be limited so as to reduce a possibility of engine stalling. An example vehicle that includes a single power source for propulsion and implements is shown in
Vehicle 100 is shown with a telescopic boom 102 that may extend and retract as indicated by arrows 108. Telescopic boom includes an outer arm 102a and an inner arm 102b. Inner arm 102b may slide in and out of outer arm 102a as indicated by arrows 108. Inner arm 102b may be extended or retracted as indicated by arrows 108 via hydraulic cylinder 120 (e.g., an actuator). The angle of telescopic boom relative to earth ground may be adjusted via hydraulic cylinder 104 (e.g., an actuator) as indicated by arrows 106. Telescopic boom 102 also includes a bucket 114. A position of bucket 114 may be adjusted as indicated by arrows 112 via hydraulic cylinder 110 (e.g., an actuator). Telescopic boom 102 may also include a second outer arm (not shown) and a second inner arm (not shown) that are configured similarly to outer arm 102a and inner arm 102b. The second outer arm and the second inner arm may be arranged in parallel with the outer arm 102a and inner arm 102b so that loads of telescopic boom 102 may be shared via the two outer arms.
Referring now to
The vehicle 100 includes a power source (e.g., an engine) 212. The power source 212 may be an internal combustion engine designed for compression ignition and/or spark ignition. For instance, in one example, the power source 212 may be a compression ignition engine configured to combust diesel fuel. The engine may additionally or alternatively be designed to combust other suitable fuels such as gasoline, biodiesel, alcohol blends, and the like. As such, the engine may include conventional components to carry out cyclical combustion operation such as one or more cylinders, an intake system, an exhaust system, a fuel delivery system, and the like. Alternatively, power source may be an electric machine.
The vehicle 100 further includes a transmission 206 mechanically coupled to the power source 212. In one example, the transmission 206 may be a hydromechanical variable transmission (HVT). For instance, the transmission may function as an infinitely variable transmission (IVT) where the transmission's gear ratio is controlled continuously from a negative maximum speed to a positive maximum speed with an infinite number of ratio points. In this way, the transmission can achieve a comparatively high level of adaptability and efficiency relative to transmissions which operate in discrete ratios. Alternatively, the transmission 206 may be another type of continuously variable transmission (CVT) capable of seamlessly shifting through a continuous range of gear ratios, such as a hydrostatic CVT that uses a variable displacement pump and a hydraulic motor, for instance. Other suitable automatic transmissions such as dual-clutch transmissions (DCTs) that employ two input clutches, may be used, in the vehicle, in other examples.
The vehicle 100 further includes implement actuators, such as hydraulic cylinder 120, hydraulic cylinder 104, and hydraulic cylinder 110. Implement actuators may be supplied with hydraulic power via pump 221. Pump 221 may be driven via a power take off (PTO) that is part of transmission 206. The implement actuators may move or operate implements that may include, but are not limited to a hydraulically powered boom, a bed lift, a lift mast assembly, a winch, and the like.
The transmission 206 may further be coupled to a drive axle 215 and wheels 217. The drive axle 215 and wheels 217 may be referred to as a traction system.
The vehicle 100 may further include one or more auxiliary components 216 and/or auxiliary systems 218. The auxiliary systems 218 may include an energy accumulator 220 (e.g., a hydraulic accumulator), a retarder 224 (e.g., an engine brake), and the like. The auxiliary components 216 may include an alternator, a water pump, a fan drive, a brake pump, etc. Generally, the auxiliary system(s) 218, during certain conditions, may receive excess power from the engine and use (e.g., waste) or store the excess energy. The auxiliary components 216 and/or auxiliary systems 218, when in operation, may receive power from the power source 212.
Vehicle 100 includes a vehicle control unit (VCU) 240 to coordinate and efficiently balance power flow in the system. The VCU 240 as well as the other control units described herein may include a processor 242 and memory 244. The memory 244 may include instructions stored therein that when executed by the processor 242 cause the VCU 240 to perform the methods, control techniques, etc., described herein. The VCU 240 may include additional signal processing types of circuits. The memory 244 may include known data storage mediums such as random access memory, read only memory, keep alive memory, combinations thereof, etc. Further, the hardware of the VCU 240 may be collocated in a common enclosure, in one example. Alternatively, the hardware may be included in two or more housings that may be located in different areas of the vehicle. The other control units described herein may be constructed similarly with regard to memory and processors as well as the enclosures that house the control unit hardware.
The VCU 240 may receive data in the form of signals from other control units in the vehicle via controller area network 250 or other communication channels. Specifically, the VCU 240 may interact with other electronic controllers in the vehicle system to receive information related to power flow between different components. As such, the VCU 240 may receive operating conditions data (e.g., engine speed, engine power, available engine power, implements power demands, etc.) that is relayed through the other control units and/or directly from vehicle sensors, systems, components, devices, and the like. VCU 240 may be designed to control adjustment of the auxiliary components 116, auxiliary systems 218, and pump 221. Additionally, the VCU 240 may provide a method for calculating uncontrollable power absorption of the vehicle auxiliary components 216 and/or auxiliary systems 218 at the current (e.g., real-time) system conditions.
The VCU 240 may also be designed to control adjustment of the implements. For example, the VCU 240 may control extension and retraction of a boom 102 via adjusting operation of distributors (e.g. hydraulic flow control valves) 120a, 120b, 104a, 104b, 110a, and 110b via communications link 254. The distributors and hydraulic cylinders are included in implement actuation system 211. Additionally, the VCU 240 may provide a method that estimates the power absorption of a pump 221. To elaborate, in one specific example, the VCU 240 may carry out the method for estimating the power absorption of the pump 221.
The vehicle 100 may also include other control units such an engine control unit (ECU) 208. The ECU 208 may be designed to adjust engine operation such as increasing or decreasing engine torque, engine speed, etc. via adjustment of a throttle, fuel injection, etc. ECU 208 may sense engine conditions via engine sensors 210 (e.g., engine speed sensor, engine air flow sensor, engine temperature sensor, etc.). Further, the ECU 208 may provide a method for calculating a net available power at the current (e.g., real-time) system conditions for power source 212.
A transmission control unit 204 (TCU) may also be included in vehicle 100. TCU is designed generate operating data for the transmission 206 such as transmission gear ratio, losses, clutch configuration, hydrostatic pump configuration (e.g., pump swivel angle), input and output shaft speed, and the like. In addition, TCU includes a processor 204a and memory 204b, which may be similar as the processor and memory of VCU 240. TCU 204 may control operation of transmission 206 via transmission sensors and actuators 207 (e.g., transmission control solenoids, transmission speed sensors, transmission temperature sensors, etc.). In one example, TCU 204 may receive human/machine interface (HMI) requests from VCU 240. TCU 204 may process the HMI requests and return modified HMI requests to VCU 240. VCU 240 may operate implements via sending control commands to distributors (e.g., 120a, 120b, 104a, 104b, 110a, and 110b) to operate implements as described in further detail herein.
The vehicle 100 may further include human machine interfaces (HMIs) 225. The HMIs 225 may include a driver demand pedal, a brake device (e.g., brake pedal), gear selector, implement control devices (e.g., implement joysticks, buttons, and the like), a touch interface, a graphical user interface (GUI), combinations thereof, and the like. Arrow 256 denotes the transfer of HMI data, such as data indicative of operator interaction with the input devices to request adjustment of selected vehicle components. For instance, the operator may request an increase in vehicle speed via driver demand pedal depression, a decrease in vehicle speed via brake pedal depression, extension of a boom via interaction with the implement control device. Thus, the VCU 240 may receive traction and implements adjustment requests from the HMIs 225.
The systems of
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VCU 240 receives HMI requests via HMIs 225 and VCU 240 passes the HMI requests to input 302a of power request calculation block 302 and input 306b of HMI command recalculation block 306. It may be understood that there are individual HMI requests from each of the HMIs even though HMI requests are shown via a single line. The power request calculation block 302 generates an implements requested power value that is based on an aggregate of HMI requests. The implements requested power value is passed to power manager input 304a and HMI command recalculation input 306a. Details of the power request calculation block are shown in
The power manager block 304 is designed to increase power distribution efficiency with regard to the transmission 206 and the implement actuation system 211. To that end, the power manager block 304 is configured to control (e.g., continuously control) a maximum power available for traction and implements taking into account the current power requests of the auxiliary component(s) and system(s), the available engine power, signals from HMIs that are generated responsive to operator interaction, system priorities that may be defined by the equipment manufacturers (e.g., the OEMs), as well as other factors. Further, by knowing the vehicle power request and the engine speed-power characteristics, the power manager block 304 may calculate a low (e.g., a minimum) target engine speed that achieves the power demands with low (e.g., minimum) fuel consumption.
In one example, the power manager block 304 splits the available net power from power source 212 based on a transmission power request, implements power request, and a priority value (P). The priority value may be the percentage of the maximum available net power to which the transmission is constrained. The priority value may be set or adjusted by the customer (e.g., OEM). In this way, a downstream vehicle manufacturer can select a power balance that is suited to their desire and/or the vehicle's end-use operating environment. The power balance selected by the customer may be expressed as a percentage allocated for the implements and for traction (e.g., 50% implements & 50% traction or 60% implements & 40% traction, etc.). The power manager block 304 may generate a transmission traction limit and an implements power limit that may expressed as a percentage of the maximum available net power. Further, the sum of the power limits for traction and the implements may be greater than 100%, in certain instances, because traction and implements may have a low chance of being simultaneously used at their maximum power during some conditions.
During some conditions, there is no power request for traction or implements. Under the no power request condition, the transmission power limit may be equal to a value of a variable P and the implements power limit may be equal to 100%−P.
In another example, where there is a transmission traction power request and no implement power request, the transmission traction power limit may be 100% and the implements power limit may be 100%−P. As such, the traction power may not be constrained by the implements when there is no power request coming from the implements.
In still another example, where there is an implements power request and no transmission traction power request, the transmission traction power limit may be P and the implements power limit may be 100%. In this way, the implements power may not be constrained by the traction power when there is not a traction power request.
Finally, where there are both an implements power request and transmission traction power request, which may be referred to as a combined maneuver, the transmission traction power limit may be 100%. Additionally, the implements power limit is calculation may be 100%−P+a controller term. The controller term may represent an output of a proportional integral (PI) controller. The output of the PI control aims to increase (e.g., maximize) engine load, thereby increasing engine efficiency by avoiding waste energy. However, in other examples, the PI controller term may be omitted from the implements power limit calculation when a mixed request is present. The aforementioned limits, in each of the different operating conditions blocks, may be continuously calculated during transmission operation and applied to the operation of the transmission for traction and implements operation. In this way, during combined maneuvers, the controlled power hand-over between the two power consumers is managed to reduce the likelihood of engine overload during transients. Further, the customer (e.g., OEM) may be allowed to set the priorities for implements and traction, specifically during the combined maneuver. As such, the customer is allowed to tailor the power balance between traction and implements according to their predilection, thereby increasing customer satisfaction. The power manager block 304 directs the implements power limit from output 304b to input 306c of the HMI command recalculation block 306.
Referring now to
HMI requests are received at input 302a and distributed to inputs 404a-410a of flow rate calculation blocks 404-410. The HMI requests may be input as voltage signals, electric current signals, or numeric values. In one example, each of flow rate calculation blocks include a relationship between an HMI request value and a hydraulic fluid flow rate. For example, if the first HMI request is for advancing a telescopic boom and the HMI request is manifest as 10 milliamps of electric current, a relationship between electric current and a flow rate to the actuators of the telescopic boom is used to look-up a hydraulic fluid flow rate according to the 10 milliamps of electric current. Block 404 outputs a flow rate of hydraulic fluid via output 404b to summing junction 412. Similarly, hydraulic fluid flow rates are provided from outputs 406b-410b of blocks 406-410 to summing junction 412. Summing junction 412 adds all of the hydraulic fluid flow rates (e.g., flow rates from each and every one of the HMI requests) and supplies the summed flow rate to input 414b of processing block 414.
A speed of pump 221 is input to multiplication block 402 at input 402a. In addition, a displacement of pump 221 is input to multiplication block 402 at input 402b. The multiplied result of pump speed and pump displacement is a maximum flow rate of the pump and it is directed from output 402c to input 414a of processing block 414.
In one example, processing block 414 may determine a lesser value of input 414a and 414b to generate a total feasible flow rate for the hydraulic system, which includes pump 221, distributors (e.g., 120a, 120b, 104a, 104b, 110a, and 110b), and hydraulic cylinders (e.g., 120, 104, and 110). The total feasible value is directed from output 414c to input 416b of multiplication block 416. A supply pressure (e.g., pressure at the output of pump 221) is provided to input 416a of multiplication block 416. Multiplication block 416 multiplies the supply pressure and the feasible flow rate to generate a total requested power for implements. The total requested output for implements is directed from output 302b to input 306a of the HMI command recalculation block.
Referring now to
The implements power limit value is received at input 306c of division block 502. The implements power requested value is received at input 306a of division block 502. Division block 502 divides the implements power limit value by the implements power requested value to generate a HMI allowance factor. The HMI allowance factor is directed from output 502c to input 504a of minimum block 504. A value of one is input to input 504b of the minimum block 504. Minimum block 504 determines a minimum of the value at input 504a and the value at input 504b to generate a HMI allowance factor. The minimum value (e.g., HMI allowance factor) is directed from output 504c to inputs 506b, 508b, 510b, and 512b of multiplication blocks 506-512.
HMI requests are received at input 306b and distributed to inputs 506a-512a of multiplication blocks 506-512. Multiplication blocks 506-512 multiply each of the unmodified individual HMI requests by the HMI allowance factor to generate modified HMI requests for each of the HMIs. The modified HMIs are directed from outputs 506c-512c to output 306d before being sent to the VCU 240. The VCU 240 commands the implement actuators via the modified HMIs. The modified HMIs may be sent out via a communications link (e.g., a controller area network or via individual conductors) to VCU 240 as indicated via output 306d and VCU 240 commands to distributors, which controls flow of hydraulic fluid to the hydraulic cylinders, thereby controlling the implements.
Thus, the HMI command recalculation block 306 rescales the HMI requests according to an HMI allowance value that is based on an implements power limit. All HMI requests are processed simultaneously so that the total power that is requested via HMIs may be considered when recalculating the HMI requests.
Referring now to
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At time t0, the transmission traction power request is zero and each of the implements power requests are zero. Consequently, the implements power request is zero. The implements power limit is a high value and the implement power flow allowed percentage for each of the implements is zero.
At time t1, the transmission traction power request begins to increase and the implements power limit is reduced in response to the increasing transmission traction power request. Each of the implements power requests are still zero. Likewise, the implements power request is zero. The implement power flow allowed percentage for each of the implements remains zero.
At time t2, power flow requests for the first and second implements begins to increase and the implements power request increases with the first and second implements requests. However, the implements power limit has been reduced so the implement power flow allowed percentage for the first and second implements is less than the implements power flow requests for the first and second implements. Thus, power flow to the implements is allowed, but it has been cut back from what has been requested since some engine power will support the transmission traction power request.
At time t3, power flow requests for the first and second implements begins to decrease and the implements power request decreases with the first and second implements requests. The implements power limit is still at a lower level so the implement power flow allowed percentage for the first and second implements decreases with the decreasing requests for power flow to the first and second implements.
At time t4, the transmission traction power request begins to decrease and the implements power limit is increased in response to the decreasing transmission traction power request. Each of the implements power requests are zero. Additionally, the implements power request is zero. The implement power flow allowed percentage for each of the implements remains zero.
At time t5, power flow request for the first implement begins to increase and the implements power request increases with the first implement request. The implements power limit has not been reduced so the implement power flow allowed percentage for the first implement follows the first implement power flow request. Thus, power flow to the implements is allowed and it is unencumbered by the implements power limit.
At time t6, power flow request for the third implement begins to increase and the implements power request increases with the third implement request. The implements power limit has not been reduced so the implement power flow allowed percentage for the first and third implements follows the implement power flow requests for the first and third implements. As a result, power flow to the first and third implements is allowed and it is unencumbered by the implements power limit.
At time t7, power flow requests for the third implement begins to decrease and the implements power request decreases with the third implement request. The implements power limit is still at a high level. The implement power flow allowed percentage for the third implement decreases and implement power flow allowed percentage for the first implement is unchanged.
At time t8, power flow requests for the first implement begins to decrease and the implements power request decreases with the first implement request. The implements power limit is still at a high level. The implement power flow allowed percentage for the first implement decreases and implement power flow allowed percentage for the third implement has reached zero.
In this way, power flow to implements may be scaled according to a transmission traction power request so that a vehicle may travel when requested even if there are implement power flow requests. The implement power flow requests may be limited based on an implements power limit.
Thus, the methods of
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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 transmission and/or vehicle hardware. Further, portions of the methods may be physical actions taken in the real world to change a state of a device. Thus, 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 vehicle and/or transmission control system. The specific routines described herein may represent one or more of any number of processing strategies such as event-driven, interrupt-driven, multi-tasking, multi-threading, and the like. As such, various actions, operations, and/or functions illustrated may be performed in the sequence illustrated, in parallel, or in some cases omitted. Likewise, the order of processing is not necessarily required to achieve the features and advantages of the example examples described herein, but is provided for ease of illustration and description. One or more of the illustrated actions, operations and/or functions may be repeatedly performed depending on the particular strategy being used. One or more of the method steps described herein may be omitted if desired.
While various embodiments have been described above, it is to be understood that they have been presented by way of example, and not limitation. It will be apparent to persons skilled in the relevant arts that the disclosed subject matter may be embodied in other specific forms without departing from the spirit of the subject matter. The embodiments described above are therefore to be considered in all respects as illustrative, not restrictive. As such, the configurations and routines disclosed herein are exemplary in nature, and that these specific examples are not to be considered in a limiting 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, internal combustion engines, and/or 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.
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