The present application relates generally to powertrain controls providing drive cycle efficiency and responsiveness enhancement and optimization, and more particularly but not exclusively to powertrain controls including transient torque management with dynamic release compensation. Controls for operation of a vehicle system including an internal combustion engine and a transmission face a number of challenges, including fuel consumption, responsiveness to operator control inputs (including perceived responsiveness sometimes referred to as drivability), protection of system components from acute failure modes, and mitigating wear of and extending life of system components, among others. Conventional approaches to powertrain controls suffer from a number limitations and shortcomings including those respecting drive cycle efficiency and responsiveness. There remains a significant need for the apparatuses, controls, methods, systems and techniques disclosed herein.
For the purposes of clearly, concisely and exactly describing exemplary embodiments of the invention, the manner and process of making and using the same, and to enable the practice, making and use of the same, reference will now be made to certain exemplary embodiments, including those illustrated in the figures, and specific language will be used to describe the same. It shall nevertheless be understood that no limitation of the scope of the invention is thereby created, and that the invention includes and protects such alterations, modifications, and further applications of the exemplary embodiments as would occur to one skilled in the art.
Exemplary embodiments include unique apparatuses, methods and systems of controlling a vehicle system including an engine, a transmission, and a control system in operative communication with and structured to control operation of the engine and the transmission. One exemplary method determines an operating point of the engine including an engine torque and an engine speed, evaluates a relationship between the operating point and a soft limit on engine torque, and modifies the soft limit to permit operation outside a boundary of the un-modified soft limit. Modification of the soft limit may be constrained by a non-adjustable limit. The operating point of the engine may be adjusted to increase engine torque above the boundary of the un-modified soft limit. In certain forms the method is effective to mitigate a vehicle speed lug event and/or avoid a transmission shift event. Further embodiments, forms, objects, features, advantages, aspects, and benefits shall become apparent from the following description and drawings.
With reference to
Vehicle system 100 further includes a control system comprising engine control module 115, transmission control module 125, and vehicle control module 135 which are configured to communicate with one another as well as with engine, transmission, and vehicle sensors via a controller-area network (CAN). Engine control module 115 may be configured to implement a plurality of controls for vehicle system 100 including cycle efficiency management (CEM) controls such as those disclosed herein as well as a variety of other controls relating to engine 110. Transmission control module 115 is configured to control and monitor transmission 125. Vehicle control module 135 is configured to receive input from operator controls 140 which may include an accelerator pedal, a brake pedal, and a parking brake control, among other controls. It is contemplated that various other operator controls may be used depending upon the particular type of vehicle chassis which is utilized and the particular arrangement of the operator cabin. Vehicle control module 135 is further configured to receive input from telematics system 130 which may be provided, for example, as a global positioning system (GPS), wireless communication networks such as cellular, Wi-Fi, and other networks configured to provide input relating to location or position.
It shall be appreciated that the controls described herein may also be implemented in connection with a variety of additional or alternate control systems including the alternative configurations disclosed herein. The illustrated control modules and their respective functionalities may be reconfigured, redistributed, supplemented, or combined. It shall also be appreciated that the controls described in the present application may be implemented in various combinations of hardware, firmware and/or software which may be provided in a single microprocessor based controller or control module or in a plurality of microprocessor based controllers or control modules such as a distributed controller system in which a plurality of controllers communicate via a CAN.
With reference to
CEM controls 230 may be provided in a variety of forms. In an exemplary embodiment CEM controls may be structured to provide vehicle speed management, torque management, cycle management and parasitic management functionalities. Exemplary vehicle speed management controls may actively manipulate a vehicle speed profile to reduce fuel consumption over the course of a mission. Exemplary torque management controls may manage the available torque, engine speed, or power based upon an estimated demand to reduce fuel consumption. Exemplary cycle management controls may allow a vehicle operator to make strategic decisions about mission parameters for reducing fuel consumption including, for example, decisions about vehicle cruise set point and fuel refill recommendations among others. Exemplary parasitic management controls may utilize information relating to vehicle and mission parameters to more efficiently control parasitic devices to mitigate reduce fuel consumption. It shall be appreciated that these and other CEM-related controls may be implemented in a variety of control systems including, for example, the control system of vehicle 100 described above in connection with
With reference to
Static torque transient management module 320 includes static speed/torque limiter 322 and gear/torque based speed limiter 321. Static speed/torque limiter 322 determines how much torque and speed the engine can produce as a function of gear, road grade and vehicle mass. This is preferably based on a pre-calibrated look-up-table rather than being changeable based on application and installation although both options are contemplated. Module 322 outputs this value to operator 349 and to gear/torque based speed limiter 321. Gear/torque based speed limiter 321 determines a final engine speed limit based on the output of the speed/torque limiter 322 and gear ratio and current engine load information and provides this value to final engine speed limit variable 399.
Dynamic torque transient management module 330 includes vehicle acceleration limiter 331 which provides a vehicle acceleration limit as a function of vehicle speed and dynamic torque estimator 332 which determines a torque requirement for a commanded vehicle operating state and outputs this value to operator 349 and to dynamic parameter adjustment module 340.
Operator 349 determines the minimum of the values it receives from static torque estimator 322 and dynamic torque estimator 332 and outputs this value to dynamic torque release module 350 and to operator 351. Dynamic torque release module 350 determines an torque limit adjustment, for example, using the techniques described herein below. The output of dynamic torque release module 350 is provided to operator 351 which sums that output with the output of operator 349 to determine a final engine torque limit and provides this value to final engine torque limit variable 398.
With reference to
The output of counter 410 is provided to error determination block 420. Error determination block 420 also receives an input from reset control logic block 411 which in turn receives an input from reset aggressiveness block 409. Error determination block 420 also receives an error adjustment factor 413 input which in turn receives as an input rate of change block 412. Error determination block 420 outputs to PI controller 430. PI controller 430 also receives input from reset control logic block 411 and input from gain combination 417 as an input. PI controller 430 determines a torque release value as a function of these inputs and outputs to the result of this determination to torque release value variable 499. Gain combination block 417 receives input from vehicle speed based gain scheduling block 414 which in turn receives input from vehicle speed block 403. Gain combination block 417 also receives as an input gear numbering based gain scheduling block 415 which in turn receives as an input gear number block 404. Gain combination block 417 also receives an input from engine speed based gain scheduling block 416 which in turn receives as an input engine speed block 405.
With reference to
Vehicle operation with the torque release features differs from the operation described above. As illustrated in graph 501 vehicle velocity is substantially constant over line segments 511, 513, 515. Vehicle velocity encounters a relatively smaller decrease over line segment 512 and a relatively small increase over line segment 514. This smoothing of vehicle velocity is an example of enhanced drivability which generally refers to the ability of a vehicle system to respond to operator commands and provide desired operation. Further details of an exemplary torque release feature shall now be described in further detail.
With reference to
As illustrated in graph 610 first operating point 601 is substantially below soft torque limit 611. As illustrated in graph 630 the engine operating point may increase in torque from first operating point 601 to second operating point 602. This may occur for example when the vehicle encounters a hill, when the operator demands greater torque output by pressing the accelerator, when the vehicle encounters a headwind or change in rolling resistance, or for a variety of other variations which shall be apparent to a person of skill in the art and the benefit of this disclosure. From operating point 602 the engine may further transition from operating point 602 to operating point 603 during which engine speed decreases. This decrease in engine speed is a function of the soft torque limit 611 which precludes an increase in torque sufficient to maintain engine speed.
With reference to graph 650 the engine operating point may proceed from point 603 to point 604 in which engine torque decreases and engine speed increases. This may occur, for example, during a transmission shift event. After the shift event the engine operating point may proceed from point 604 to point 605 or point 607. Under the scenario which the operating point transitions from point 604 to point 605, at point 605 although the hill or grade increase has ended the engine is unable to return to its target speed since it is constrained by soft torque limit 611. At the same time engine torque may be constrained to the magnitude of operating point 606 which may itself be less than desired. The transition may also occur from operating point 604 to operating point 607. In this scenario the engine is able to return to its target speed but with a reduced torque output which is less than desired. Either of operating points 605 or 607 may result in an individual vehicle speeding or transmission shift event.
With reference to graph 670 there are illustrated transitions and operating points which occur when the vehicle returns to a level grade. The vehicle operating point may transition from operating point 605 directly to point 609 or may transition from vehicle operating point to operating point 608 and then to operating point 609. From operating point 609 the vehicle may return to its original operating point 601.
With reference to
As illustrated in graph 750, once the torque release function has modified the soft torque limit, vehicle torque may increase from operating point 702 up to operating point 703. This allows the vehicle to maintain engine speed by increasing torque. With reference to graph 770, when the vehicle returns to normal grade the engine operating point may return from operating point 703 to operating point 702 and then to operating point 701. After the transition from operating point 703 and operating point 702 the modified soft torque limit 713 may transition back to the original soft torque limit 711. As can be appreciated by comparing the graphs of
It shall be appreciated that a number of operating point adjustment and control techniques are contemplated. In certain forms the engine operating point may be adjusted by increasing engine torque above the un-modified soft limit. In certain forms the engine operating point may be adjusted by a combination of increasing engine torque above the un-modified soft limit and decreasing engine speed. Such adjustments may be determined based upon a weighted optimization of a demand responsiveness criterion and fuel consumption criterion. The weighted optimization criteria may be operator controllable based upon various different fuel economy and operational responsiveness criteria. The weighted optimization may also be dynamically adjusted during a vehicle operation based upon changed operator criteria or based upon the past operation of the vehicle and its impact relative to the established criteria. For example, the weighting afforded to fuel economy may be increased if recent operational history has moved away from a fuel economy target.
A number of torque limit adjustment techniques and control criteria are contemplated. These include both torque limit release criteria and torque limit reinstatement criteria as well as other types of torque limit adjustments and modifications. The torque limit adjustments may be based upon a predetermined relationship between a current operating point of the engine and a soft limit on engine torque. For example, the soft torque limit may be modified when the operating point is within a given magnitude or a given percentage of the limit. The torque limit adjustment may also be based upon a predicted future engine operating point. The predicted future operating may be based upon a computation, such as a mathematical derivative of an operating point curve, or linear or non-linear prediction based upon a plurality of recent operating points. The predicted future operating point may also be based upon global positioning system (GPS) information which may indicate changes in road grade, elevation or altitude. The predicted future operating point may also be based upon information of prior operation of the vehicle, for example, data relating to prior mission histories may be stored in a non-transitory computer readable medium and utilized to predict future operating points. In certain forms mission history data may be utilized in conjunction with distance traveled or mission time elapsed. In certain forms mission history data may be utilized in conjunction with GPS data. In certain forms the predicted future operating point may be based upon a predetermined road parameter specification such as a road grade specification. For example, the prediction may be based upon a road grade limit for a given elevation change. In certain forms the predicted future operating point may be based upon information from an inclinometer and/or a forward horizon terrain profile either alone or combined as a fused grade sensor value. The fused grade sensor may be determined as a weighted average of the information from the inclinometer and the forward horizon terrain profile.
With reference to
While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only certain exemplary embodiments have been shown and described and that all changes and modifications that come within the spirit of the inventions are desired to be protected. It should be understood that while the use of words such as preferable, preferably, preferred or more preferred utilized in the description above indicate that the feature so described may be more desirable, it nonetheless may not be necessary and embodiments lacking the same may be contemplated as within the scope of the invention, the scope being defined by the claims that follow. In reading the claims, it is intended that when words such as “a,” “an,” “at least one,” or “at least one portion” are used there is no intention to limit the claim to only one item unless specifically stated to the contrary in the claim. When the language “at least a portion” and/or “a portion” is used the item can include a portion and/or the entire item unless specifically stated to the contrary.
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