CN121316869A - Predictive dynamic speed control of vehicles traveling on a ramp route - Google Patents

Abstract

A vehicle system includes a powertrain having a prime mover, a transmission with multiple gears, and a basic brake. The vehicle system includes an electronic control system configured to determine, before reaching a downhill section, a target vehicle speed, a target transmission gear, and a downhill vehicle speed limit; control the vehicle to reach the target downhill vehicle speed and the target transmission gear before or upon reaching the downhill section; and control the vehicle to not exceed the downhill vehicle speed limit during the downhill section.

Description

Predictive dynamic speed control of vehicles traveling on a ramp route

Technical Field

The present application relates generally to vehicle control systems and, more particularly, but not exclusively, to predictive dynamic speed control of vehicles traveling along a ramp route and related devices, processes, systems and techniques.

Background

Current vehicle speed control methods suffer from a number of drawbacks and deficiencies, including those related to controlling the vehicle to travel along a hill path, including, for example, those reflected in fuel economy and premature wear, overheating, and other problems caused by overuse of the foundation brakes. There remains a significant need for the unique apparatus, methods, and systems disclosed herein.

Disclosure of illustrative embodiments

In order to clearly, concisely, and accurately describe the illustrative embodiments of the present disclosure, the manner and process of making and using the same, and to enable the practice, making and using thereof, reference will now be made to certain illustrative embodiments, including the embodiments illustrated in the drawings, and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, 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.

Disclosure of Invention

The present disclosure includes a unique system that includes dynamically controlling and adjusting vehicle speed prior to or upon reaching a downhill segment of a route. In one embodiment, a vehicle system includes an electronic control system in operative communication with a prime mover, a transmission, one or more driveline retarders, and a foundation brake of a vehicle. The electronic control system is configured to determine a downhill road grade, a downhill vehicle speed limit, a pre-downhill target vehicle speed, a pre-downhill target transmission gear, a downhill target vehicle speed, and a downhill target transmission gear of the vehicle prior to reaching the downhill road segment. The vehicle is controlled to achieve a pre-downhill target vehicle speed and a pre-downhill target transmission gear of the vehicle before or upon reaching a downhill road segment. Further, the vehicle is controlled not to exceed a downhill vehicle speed limit during the downhill road segment. In another embodiment, the electronic control system is configured to determine a roll-out target speed of the vehicle over a portion of the downhill road segment and to control the vehicle to accelerate toward the roll-out target speed when the vehicle reaches the portion of the downhill road segment. Further embodiments, forms, objects, features, advantages, aspects, and benefits shall become apparent from the following description and drawings.

Drawings

FIG. 1 is a schematic illustration of a vehicle having a control system for controlling the speed of the vehicle.

Fig. 2A-2D are schematic diagrams depicting certain aspects of a vehicle route as the vehicle approaches a downhill segment of the route.

Fig. 3A-3C are schematic diagrams depicting certain types of vehicle routes and corresponding operational aspects of the vehicle relative to a taxi transition section of the route.

Fig. 4 is a flowchart of an exemplary procedure for controlling the speed of a vehicle prior to a downhill stretch.

FIG. 5 is a schematic diagram depicting certain aspects of a software architecture for controlling various operational aspects of a vehicle.

Detailed Description

Referring to FIG. 1, a schematic diagram of an exemplary vehicle 100 including a powertrain 102 that is incorporated within the vehicle 100 is shown. In the illustrated embodiment, the powertrain 102 includes a prime mover 104, such as an engine, configured and provided as an internal combustion engine, structured to generate power for the vehicle 100. The powertrain 102 also includes a transmission 106 that is connected to the prime mover to adapt and transmit an output torque of the prime mover to a driveline 107 that includes a drive shaft 108. In the illustrated embodiment, the transmission 106 may be disengageably connected to the engine crankshaft 105 via a clutch 109.

In other embodiments, the transmission 106 may be disengageably connected to the engine crankshaft 105, and engagement and disengagement may be achieved through operation of a main clutch disposed at a front portion of the transmission, through operation of the transmission to shift gears into neutral, or through other clutch and/or shift arrangements. Various embodiments contemplate that transmission 106 may be an automatic transmission, an automatic manual transmission, a manual transmission, or any other suitable transmission having a disconnect device 111 operable to selectively engage and disengage engine 104 with drive train 107.

In the rear wheel drive configuration shown for vehicle 100, driveline 107 of powertrain 102 includes a final drive 110 having a rear differential 112 connecting propeller shaft 108 to rear axles 114a, 114 b. It is contemplated that components of powertrain 102 may be positioned in different locations throughout vehicle 100. In one non-limiting example of a vehicle 100 having a front wheel drive configuration, the transmission 106 may be a variable speed propeller shaft and a final drive 110 may be present at a front portion of the vehicle 100 that connects front axles 116a and 116b to the engine 104 via the variable speed propeller shaft. It is also contemplated that in some embodiments, the vehicle 100 is in an all-wheel drive configuration.

In the illustrated embodiment, the vehicle 100 includes two front wheels 122a, 122b mounted to the front axles 116a, 116b, respectively. The vehicle 100 also includes two rear wheels 126a, 126b mounted to the rear axles 114a, 114b, respectively. It is contemplated that vehicle 100 may have more or fewer wheels than shown in fig. 1. The vehicle 100 also includes foundation brakes 124a, 124b, 127a, 127b for automatically mechanically retarding one or more of the wheels 122a, 122b, 126a, 126b, respectively, upon application of the brake pedal 128 and/or in response to one or more vehicle speed control outputs. The vehicle 100 also includes an engine braking system 129 operable to slow down the engine 104 and slow down the vehicle 100 without friction braking, such as by compression release braking, exhaust braking, or the like. The vehicle 100 may also include various components not shown, such as a fuel system including a fuel tank, a front differential, a suspension, an engine air intake system, and an exhaust system that may include an exhaust aftertreatment system, to name a few. In certain embodiments, the vehicle 100 may include an electric machine and a battery of suitable capacity to provide a hybrid electric powertrain, a fuel cell, other power sources, and/or one or more driveline retarders.

The vehicle 100 includes an electronic or Engine Control Unit (ECU) 130, sometimes referred to as an electronic or Engine Control Module (ECM) or the like, that is dedicated to regulating and controlling the operation of the engine 104. An operator may connect an accelerator pedal 145 and/or other throttle control mechanism to ECU 130 to initiate fueling. A Transmission Control Unit (TCU) 140 is shown in the vehicle 100, which is dedicated to regulating and controlling the operation of the transmission 106. ECU 130 and TCU 140 are each in operative communication with, for example, a plurality of vehicle sensors (not shown) in vehicle 100 for receiving and transmitting operating conditions of vehicle 100, such as temperature conditions, pressure conditions, speed conditions, fuel conditions, flow conditions to and from the engine, terrain conditions, weather conditions, global Positioning System (GPS) data, and vehicle mass. It is contemplated that ECU 130 and TCU 140 may be integrated within engine 104 and transmission 106, respectively.

The vehicle 100 also includes a Vehicle Speed Management (VSM) controller or control unit 150 that may be dedicated to controlling the operations described herein and/or to intermediately controlling to regulate and control the powertrain 102 in the vehicle 100. VSM control unit 150 is in operative communication with ECU 130 and TCU 140. In certain embodiments, some or all of VSM control unit 150 may be integrated within ECU 130 or TCU 140 or other vehicle control units. In other embodiments, at least VSM control unit 150 communicates with ECU 130 and/or TCU 140 via a data link provided by a wired or wireless connection such that outputs of VSM control unit 150 determined independently of ECU 130 and/or TCU 140 may be provided to ECU 130 and/or TCU 140.

The VSM control unit 150 may also be in operative communication with, for example, one or more of the plurality of vehicle sensors in the vehicle 100 for receiving and transmitting conditions of the vehicle 100, such as temperature and pressure conditions, route conditions, terrain conditions, speed conditions, and weather conditions. It is contemplated that at least a portion of the conditions and/or measured inputs used by VSM control unit 150 to interpret signals may also be received from ECU 130 and/or TCU 140 in addition to or instead of the plurality of vehicle sensors. Further, the VSM control unit 150 may include one or more processors or controllers. Such as an Idle Coast Management (ICM) controller, a reverse drag (motoring) controller, etc.

VSM control unit 150 and/or ECU 130 and TCU 140 include stored data values, constants and functions, and operating instructions stored on, for example, a computer readable medium. Any of the operations of the exemplary procedures described herein may be performed, at least in part, by VSM control unit 150. In certain embodiments, VSM control unit 150 comprises one or more controllers structured to functionally execute the operations of the controllers. Additional details of certain exemplary embodiments of controller operation are discussed below. It should be understood that the operations shown are merely illustrative, and that operations may be combined or split and added or removed and reordered, in whole or in part, unless explicitly stated to the contrary herein.

Certain operations described herein include operations to interpret or determine one or more parameters. Interpretation or determination as utilized herein includes receiving a value by any method, including at least receiving a value from a data link or network communication, receiving an electronic signal (e.g., a voltage, frequency, current, or Pulse Width Modulation (PWM) signal) indicative of the value, receiving a software parameter indicative of the value, reading the value from a storage location on a computer readable medium, receiving the value as a runtime parameter by any means known in the art, and/or by receiving a value from which the interpreted or determined parameter can be calculated, and/or by referencing a default value that is interpreted or determined as a parameter value.

ECU 130, TCU 140, and VSM control unit 150 are exemplary components of an integrated circuit based Electronic Control System (ECS) that may be configured to control various operational aspects of vehicle 100 and powertrain 102, as described in greater detail herein. ECSs according to the present disclosure may be implemented in many forms and may include many different elements and element configurations. In certain preferred forms, the ECS may incorporate one or more microprocessor-based or microcontroller-based electronic control units, sometimes referred to as electronic control modules. An ECS according to the present disclosure may be provided in the form of a single processing component or computing component or in the form of a plurality of operatively coupled processing components or computing components, and may include digital circuitry, analog circuitry, or a hybrid combination of both types of circuitry. The integrated circuit system of the ECS and/or any of its constituent processors/controllers or other components may include one or more signal conditioners, modulators, demodulators, arithmetic Logic Units (ALUs), central Processing Units (CPUs), limiters, oscillators, control clocks, amplifiers, signal conditioners, filters, format converters, communication ports, clamping circuits, delay devices, memory devices, analog-to-digital (a/D) converters, digital-to-analog (D/a) converters, and/or different circuitry or functional components as will occur to those of skill in the art for providing and performing the communication and control aspects disclosed herein.

An exemplary embodiment of the VSM control unit 150 is configured to dynamically adjust the vehicle speed toward a target speed before the vehicle travels on a downhill segment of the route. In an exemplary embodiment, the vehicle speed may be dynamically adjusted to the target speed before or upon reaching a downhill segment of the route. The VSM control unit 150 may use the look-ahead data and vehicle parameters, such as vehicle mass, to determine or predict the terminal speed and transmission gear of the vehicle. The terminal speed and transmission gear of the vehicle may be determined based on any one or more of the foregoing conditions (i) such that the vehicle safely traverses the downhill road segment based on road slope or grade, taking into account vehicle operating parameters such as vehicle mass, rear axle speed ratio, tire rolling radius, and/or other parameters affecting the vehicle's ability to traverse the downhill road segment. (ii) After all losses (including aerodynamics, rolling friction and driveline losses) are considered, the terminal speed and transmission gear may be determined based on a condition that the driveline retarder has sufficient retarding power to compensate for road grade power. (iii) The determination of the terminal speed and the transmission gear may or may not involve driver intervention or vehicle control. The VSM control unit 150 may determine the target speed and transmission gear based on the rules that (iv) the target speed is less than the terminal speed and speed limit, (v) the target gear is less than the highest transmission gear allowed at the terminal speed and speed limit, (vi) the target speed and gear is the highest of the possible values that satisfy condition (iv), condition (v) and conditions (e.g., (i), (ii) and (iii)) for defining the terminal speed and transmission gear. The VSM control unit 150 may also be configured to dynamically adjust the vehicle speed as the vehicle travels along the downhill segment of the route in addition to dynamically adjusting the vehicle speed toward the target speed before the vehicle is in the downhill segment of the route. The VSM control unit 150 is also configured to control the vehicle speed so that it does not exceed the speed limit during the downhill segment.

Another exemplary embodiment of VSM control unit 150 may be configured to dynamically adjust vehicle speed to a coasting transition target speed over a portion of a downhill road segment. In an exemplary embodiment, when the vehicle reaches a portion of a downhill path, the VSM control unit 150 may control the vehicle speed to accelerate toward a coasting transition target speed. For example, the VSM control unit 150 may determine the coasting transition target speed in response to a speed limit (e.g., a first posted speed limit) for the portion of the downhill road segment and a speed limit (e.g., a second posted speed limit) for a road segment that is forward or ahead of the portion of the downhill road segment using the look-ahead data.

It should be appreciated that a given downhill road segment according to the present disclosure may be preceded by an uphill road segment leading to a local vertex, a substantially flat or zero slope road segment, and/or a downhill road segment that differs from the slope of the given downhill road segment. Likewise, a downhill vehicle speed limit according to the present disclosure may include a speed limit of a vehicle associated with a downhill road segment that is preceded by any one or more of the preceding road segments of the type described above. Similarly, the pre-downhill vehicle target speed according to the present disclosure may include a target speed of a vehicle associated with any one or more of the aforementioned types of road segments preceding the downhill road segment.

It is contemplated that the look-ahead data for determining the terminal speed may include data collected using a variety of techniques, including, for example, terrain data, environmental conditions, road conditions, proximity or location of other vehicles, distance or distance to one or more other vehicles, speed of one or more other vehicles, route conditions, upcoming grade or road slope conditions, GPS data, map data, inputs from one or more other vehicles or forward looking radar systems, and/or one or more models of vehicle 100, including estimated mass, aerodynamic drag, rear axle ratio, rolling radius of tires, and other conditions associated with vehicle 100. Terrain data may be gathered from grade sensors, such as inclinometers or computer models structured to determine or estimate grade information from map or Geographic Information System (GIS) datasets, which may be provided on the vehicle or received via transmissions from remote locations or by a combination of the techniques.

Referring to fig. 2A-2D, there are shown graphs 200a, 200b, 200c, and 200D depicting the vehicle 100 at a plurality of locations along a route 202 that includes a downhill road segment 204. In the position shown in fig. 2A, the vehicle 100 is traveling along a road segment 202 that precedes a downhill road segment 204. At the location shown (or one or more additional or alternative locations prior to the downhill segment), the electronic control system of the vehicle 100 may obtain look-ahead data including at least one of future road grade and speed limit information for the route 202. The look-ahead data may be obtained from one or more on-board systems, one or more off-board systems via a wireless communication link, or a combination thereof. In some embodiments, for example, the electronic control system of the vehicle 100 may identify a downhill segment in response to one or more GPS signals and on-board map information.

The electronic control system of the vehicle 100 may utilize at least one of the look-ahead data or the future road grade and speed limit information to determine whether the vehicle 100 is approaching the downhill road segment 204 and, in response, to determine a downhill front target speed, a downhill front target transmission gear, a downhill target speed, and a downhill target transmission gear. The pre-downhill target speed, pre-downhill target transmission gear, downhill target speed, and downhill target transmission gear may be determined according to an objective function optimization configured to minimize fuel consumption (or energy consumption, e.g., in the case of an electric vehicle, a hybrid-combustion electric vehicle, or a fuel cell vehicle) that is constrained by vehicle speed limits and may be subject to one or more additional constraints, such as, for example, minimum vehicle speed, maximum travel time, target deceleration rate, or other constraints that will occur to those of skill in the art after having the benefit of this disclosure and understanding. The vehicle speed limit constraint may be a nominal or legal speed limit obtained from one or more on-board systems, one or more off-board systems via a wireless communication link, or a combination thereof.

The electronic control system of the vehicle 100 is also configured and operable to control the vehicle speed to reach a pre-downhill target speed and to control the vehicle transmission to a pre-downhill target transmission gear before or upon reaching the start of the downhill road segment 204. The pre-downhill target speed and the pre-downhill target transmission gear may be used by the vehicle 100 during a portion or substantially all of the downhill road segment 204, or may be varied according to one or more downhill target speed limits and/or one or more downhill target transmission gears. The pre-downhill target speed and the pre-downhill target transmission gear may be selected to provide an initial vehicle speed that is less than the downhill vehicle speed limit, and a transmission gear that predicts a speed of the vehicle 100 at a predetermined location along the downhill path to the downhill vehicle speed limit. The fuel and/or energy consumption optimization may allow the vehicle to coast a portion or all of the distance between the position of the vehicle 100 depicted in fig. 2A and the position depicted in fig. 2B and then accelerate along the downhill road segment 204 to a downhill vehicle speed limit.

In the position depicted in fig. 2B, the vehicle 100 has reached an apex 201 at the start of the downhill road segment 204. At or before reaching the vertex 201, the speed of the vehicle 100 has preferably been controlled to bring the vehicle speed to a target speed, and the transmission of the vehicle has preferably been controlled to engage the target transmission gear. The vehicle 100 may begin to descend along the downhill road segment 204, at least initially traveling at or about the downhill target speed at the downhill target transmission gear.

In the position shown in fig. 2C, the vehicle 100 is traveling along a point of the downhill path 204. The electronic control system of the vehicle 100 is configured and operable to maintain or reduce the speed of the vehicle 100 to or below a downhill vehicle speed limit. As the vehicle 100 travels along the downhill road segment 204, the electronic control system of the vehicle 100 may control one or more components of the driveline to at least one of reduce the speed of the vehicle and maintain the vehicle speed to meet the downhill vehicle speed limit. The electronic control system may, for example, engage and operate one or more of a driveline retarder, a transmission downshift, and a vehicle foundation brake to maintain or reduce the speed of the vehicle 100 to or below a downhill vehicle speed limit. In some operating scenarios, the electronic control system may be configured and operated to work the driveline retarder in conjunction with the foundation brake to reach the downhill vehicle speed limit. For short-range downhill operating scenarios (e.g., local grade changes), some such scenarios may be performed. It should be appreciated that a driveline retarder in accordance with the present disclosure may include, for example, an engine brake (such as a compression release brake or an exhaust brake), a hydraulic driveline retarder, a driveline/vehicle accessory and electromagnetic driveline retarder, a motor/generator based regenerative brake, or other driveline retarder as would occur to one skilled in the art having the benefit of this disclosure and understanding.

At one or more points during the downhill path, the electronic control system may control operation of the driveline retarder to facilitate at least one of reducing a speed of the vehicle and maintaining the speed of the vehicle without applying the foundation brake. Operation of the engine brake may be prioritized as a first sequential operation for maintaining or reducing vehicle speed along the downhill road segment 204.

At one or more points during the downhill path, the electronic control system may downshift the transmission to a lower gear during the downhill path to facilitate at least one of reducing the speed of the vehicle and maintaining the speed of the vehicle. Transmission downshifts may be prioritized as a second sequential operation for maintaining or reducing vehicle speed along the downhill path segment 204 (after engine braking operation or placed in a position that is less important than engine braking operation). Alternatively, transmission downshifts may be prioritized as a first sequential operation for maintaining or reducing vehicle speed along the downhill road segment 204 (prior to or at a higher position than the operation of engine braking).

At one or more points during the downhill path, the electronic control system may operate the foundation brake during the downhill path and during a downshift of the transmission to facilitate at least one of reducing the speed of the vehicle and maintaining the speed of the vehicle. Operation of the foundation brake may be performed in conjunction with transmission downshifts to maintain or reduce vehicle speed along the downhill path 204. For example, the operation of the foundation brake may be performed while the transmission clutch is off and at least one of the prime mover and the road wheel are separated, and the transmission and the wheels are separated. Such operations may include braking cushioning of otherwise uncontrolled or very low level of downhill acceleration that may occur when the road wheels are decoupled from the prime mover and/or transmission. The operation of the foundation brake may be prioritized as a third sequential operation for maintaining or reducing the vehicle speed along the downhill road section 204 (after or at a position that is less than the transmission downshift), or alternatively may be given a higher priority.

The present disclosure contemplates a variety of brake buffering operations that may be used to reduce the vehicle speed to a pre-downhill vehicle speed target, and/or to reduce or maintain the speed of the vehicle at or below a downhill vehicle speed limit. Some example brake buffering operations include operating a foundation brake to reduce vehicle speed until the vehicle is able to downshift. Some example brake buffering operations include operating a foundation brake during a transmission shift to limit or prevent positive vehicle/engine acceleration or to provide negative vehicle/engine acceleration. Some example brake buffering operations include operating the foundation brake and then monitoring vehicle/engine speed to determine whether additional operations of the foundation brake are performed. Some example brake buffering operations include adjusting retarding power in response to local changes in road grade. Some example brake buffering operations include operating a foundation brake to avoid or mitigate a downshift event. Some exemplary brake buffering operations include operating a foundation brake to avoid or mitigate the need for a control action to reduce the vehicle speed below a speed limit. Some example brake buffering operations include, prior to a downhill segment, first controlling one or more components of the powertrain to provide at least one of reducing a speed of the vehicle and maintaining the speed of the vehicle without applying the foundation brake, and in response to determining that first controlling is not effective to achieve a target vehicle speed before the downhill, operating the foundation brake to one of reduce the speed of the vehicle and maintain the speed of the vehicle.

Braking bump may be used when or during near maximum driveline retarding capacity. The brake cushion may be used with a gear shift. Braking buffering may be performed to reduce the vehicle speed below the target speed while continuing to apply the driveline retarder. This may be used to test whether there is a temporary road grade change so that vehicle speed is maintained without performing a full shift.

In the position shown in fig. 2D, the vehicle 100 is traveling along a point of the downhill section 204, near the end of the downhill section 204. The electronic control system of the vehicle 100 may utilize the look-ahead data to determine whether the vehicle 100 is approaching the end of the downhill road segment 204 and, in response to such determination, control the vehicle 100 to perform a hill glide transition (HRO) operation to accelerate the vehicle 100 over a portion of the downhill road segment 204. When the vehicle 100 reaches the portion of the downhill road segment 204, the HRO operation may control the vehicle speed to accelerate toward the coasting transition target speed. The electronic control system may be configured to determine a coasting transition target speed of the vehicle on a portion of the downhill road segment and when the vehicle reaches a predetermined location or portion of the downhill road segment, control the vehicle to allow acceleration towards the coasting transition target speed in response to gravity. The electronic control system of the vehicle 100 may determine the coasting transition target speed in response to one of a first indicated speed limit of the portion of the downhill road segment and a second indicated speed limit of a forward segment ahead of the portion of the downhill road segment.

Fig. 2A-2D are examples of Predictive Dynamic Speed Control (PDSC) that may be implemented in and executed by an electronic control system of vehicle 100. The PDSC may include many additional and/or alternative aspects. In one aspect, the PDSC may limit the speed of the vehicle 100 to a speed limit indicated on a substantially flat road segment. For example, if the vehicle travel path remains substantially flat, but the indicated speed limit decreases, the PDSC may control the vehicle speed to gradually decrease to the new indicated speed limit in a manner similar to that described for the downhill operation. The PDSC may operate in both cruise control and accelerator-based driving. During cruise control operation, the PDSC may reduce the vehicle speed from a nominal isochronous cruise control speed to a safe downhill speed. In accelerator-based operation, the PDSC may prevent the driver from accelerating back to the indicated speed limit above the safe downhill speed.

In further aspects, when the vehicle approaches a lower indicated speed limit and the driver takes no action to reduce the vehicle speed, the PDSC may activate and apply the driveline retarder and/or the downshift to reduce the vehicle speed to the new indicated speed limit. After reaching the new indicated speed limit, the PDSC may be inactive and give the driver full control of the vehicle if the vehicle is not on a downhill grade. In another embodiment, after reaching the new indicated speed limit, the PDSC may remain active and force the vehicle speed to reach the indicated speed limit at all times.

On the other hand, when the vehicle approaches a downhill grade and the driver takes no action but attempts to increase the vehicle speed to the indicated speed limit, the PDSC may activate and apply engine braking and/or a downshift to reduce the vehicle speed and gear to the desired values, thereby achieving a safe downhill grade. The PDSC may remain active throughout the descent, effectively maintaining vehicle speed at or below the descent speed limit.

In further aspects, the PDSC may determine when and when a hill coast transition (HRO) operation should begin at a time when a gradual deceleration/downshift should begin to prepare the vehicle for configuration prior to a downhill road segment. The PDSC may determine one or more predicted speeds as vectors corresponding to a predetermined look-ahead range (e.g., a2 km look-ahead range). These vectors may be calculated at each time step and used to determine when to take action to meet vehicle speed requirements, such as a pre-downhill vehicle target speed, a pre-downhill target transmission gear, a downhill target speed limit, a downhill target transmission gear, and/or a coasting transition target speed and a coasting transition target transmission.

In another aspect, the PDSC may perform an actual cruise control mode to automatically fuel the vehicle to maintain the target speed on a flat road during a preliminary configuration of the vehicle prior to a downhill grade (e.g., when the vehicle is on a substantially flat road segment) and the vehicle has reached its target transmission gear and speed.

In further aspects, the PDSC may perform the correction mechanism during a progressive deceleration process before the descent. For example, if the vehicle mass is underestimated or overestimated, the PDSC may observe errors during the pre-downhill configuration operation and issue commanded corrections in the form of reduced or increased fueling, reduced or increased engine braking, and/or more aggressive or less aggressive downshifts, and/or use of the vehicle foundation brakes as the vehicle approaches the apex ahead of the downhill path. In this way, the PDSC may rely on the fact that as it approaches the apex ahead of the downhill path, the prediction may become more accurate over time, thereby making the corrective action more efficient.

In a further aspect, when the driveline retarder is unable to control the downhill speed and is unable to downshift (e.g., due to complete loss of GPS), the PDSC engages the vehicle foundation brake to reduce the engine speed, thereby enabling the downshift. Other situations where foundation brake switches may be utilized are when there is uncertainty in the input signal to the PDSC, such as vehicle mass estimation, grade data. PDSC may utilize redundancy coefficients of the engine retarding torque curve to improve robustness. If the foundation brake temperature increases, the redundancy factor may be higher to reduce the likelihood that the foundation brake must be used. The higher redundancy may result in lower target transmission gear and vehicle speed during downhill grades. Different brake buffering techniques may result in different brake temperature profiles. Thus, calibration of the brake buffering parameters may be obtained to allow the PDSC to achieve low brake temperatures in conjunction with the foundation brake operation request. The PDSC may utilize the foundation brake as a torque compensating device during transmission shifts to maintain vehicle speed while descending a hill.

In further aspects, the PDSC may utilize a feedback mechanism that determines whether the vehicle is accelerating or overspeeding, or whether the driveline retarder is not being used at its predicted maximum capacity, although the driveline retarder is already being used at its maximum capacity. For example, in the event that the vehicle mass is underestimated and the actual road grade is greater than the predicted road grade, the PDSC determines the desired gear as gear 12, but the actual desired gear should be 8. In this case, the PDSC may make maximum use of the driveline retarder and use the foundation brake to reduce vehicle speed to a speed at which the transmission may downshift, and then perform the downshift. The sequence may be repeated until the vehicle reaches a safe downhill transmission gear and speed. The PDSC may similarly use this feedback mechanism when GPS data is lost and the safe transmission gear has been similarly erroneously determined. In another example, when the powertrain uses its predicted retarding capability in the future by comparing actual power to predicted power, the PDSC may execute an upshift mechanism to achieve a higher transmission gear. One specific scenario in which this mechanism may be applied is when look-ahead data is lost and the vehicle returns to a flat road, the PDSC may identify to restore the vehicle to a normal state.

In some scenarios, the driver may further reduce the vehicle speed from the PDSC target speed, such as in a construction area where the predicted speed limit does not reflect the actual speed limit. The PDSC may support a sequence of driver intervention mechanisms in which the driver depresses the foundation brake to reduce the vehicle speed. After applying the foundation brakes, the driver may depress the accelerator pedal to increase the vehicle speed, during which the PDSC limits the vehicle speed and response to the accelerator pedal request to predetermined speed limits (such as one of the limits disclosed herein) and/or acceleration limits (such as an acceleration ramp limit). If the driver depresses the accelerator pedal in an attempt to exceed the PDSC target speed and/or target acceleration, the PDSC may limit the vehicle speed and/or acceleration to within limits.

In some scenarios, the driver may intervene in the PDSC operation by a manual gear request, for example, by manually downshifting the transmission gear below the gear initially selected by the PDSC. In such a scenario, the PDSC may select the final transmission gear as the minimum between the PDSC gear request and the driver gear request. Since the PDSC commanded speed is responsive to the final transmission gear request, the PDSC commanded speed may be further reduced from the original PDSC commanded speed if the final gear request is a driver requested gear.

In some scenarios, the driver may intervene in the PDSC operation by a foundation brake request, e.g., the driver may depress the foundation brake pedal to a greater extent in an effort to achieve a greater vehicle deceleration than the PDSC would otherwise provide. In such a scenario, the driver's foundation braking may take precedence over the PDSC request. In another scenario, the final foundation brake request may be the sum of the PDSC requested brake request and the driver requested brake request.

In further aspects, the PDSC may perform a hill coasting transition (HRO) action by utilizing the grade of the end of the downhill segment to perform a reverse drag, neutral, or engine off coast to meet the indicated speed limit requirements, improve fuel economy, and/or improve drivability.

The PDSC may perform any type of HRO operation depending on the profile characteristics and grade of the indicated speed limit shown in (but not limited to) fig. 3A-3C. In a first example of the HRO operation shown in fig. 3A, the indicated speed limit is increased before the end of the downhill segment, and the PDSC increases the downhill speed target to allow the vehicle speed to gradually accelerate to the increased indicated speed limit while on the downhill segment. The level of gradual change in vehicle speed before the increased indicated speed limit may be determined by a predefined calibration of the amount by which the vehicle speed is above the indicated speed limit on a downhill slope and/or by meeting a requirement that the distance by which the vehicle speed is above the indicated speed on a downhill slope is less than the predefined calibration. The allowable amount of vehicle speed above the indicated speed limit on the downhill slope may be determined based on the indicated speed limit on the downhill slope and the increased indicated speed limit. In a second example of the HRO operation shown in fig. 3B, the indicated speed limit is increased at or after the end of the downhill road segment, and the PDSC increases the downhill speed target to allow the vehicle speed to gradually accelerate to the increased indicated speed limit while on the downhill road segment. At or after the end of the downhill segment, the PDSC limits the vehicle speed to avoid that the vehicle speed exceeds an allowable vehicle speed ramp level before the increased nominal speed limit, independent of the driver acceleration action. The restriction may be performed by a feature such as a road speed limiter. The level of gradual change in vehicle speed before the increased indicated speed limit may be determined by a predefined calibration of the amount by which the vehicle speed is above the indicated speed limit on a downhill slope and/or by meeting a requirement that the distance by which the vehicle speed is above the indicated speed on a downhill slope is less than the predefined calibration. The allowable amount of vehicle speed above the indicated speed limit on the downhill slope may be determined based on the indicated speed limit on the downhill slope and the increased indicated speed limit. In a third example of the HRO operation in fig. 3C, the indicated speed limit does not change before, during, and after the downhill, and the PDSC increases the vehicle speed from the target downhill speed back to the indicated speed. In some operating scenarios, HRO operation may be disabled due to a low confidence in the predictions of the resulting vehicle speeds. In some operating scenarios, if the vehicle speed is above the target during HRO, HRO operation may switch to engine braking operation near the end of the downhill road segment and maintain or downshift the transmission for a period of time.

For applications where more than one retarder is present, the retarding power capability used by the PDSC may be the combined power capability of all retarders. This combined power capability is used to determine the target speed and target gear and the moment at which a progressive deceleration/downshift is initiated before the descent. If the retarder is a driveline retarder, its corresponding power curve will take into account the effects of coolant and oil temperature. These temperatures may also come from predictive models based on look-ahead data. The retarding devices may include, but are not limited to, any device that provides retarding power, compression release brakes, exhaust gas, VGT, exhaust throttle, intake throttle, all types of driveline retarders (hydraulic, electromagnetic, etc.), engine/vehicle accessories (compressors, fans) or any parasitic load, aerodynamic drag enhancers/reducers (such as active deflectors and automatic chassis hoist systems), multiple axles (to increase rolling friction and axle losses).

In such applications, the PDSC may perform responsive and predictive actions. In responsive action, the braking capacity of the driveline retarder decreases when the coolant temperature is high. This derating in the driveline retarder is taken into account and may result in a reduction in the calculated target speed and target gear. Such control actions continue to occur, including before and during downhill grades. In a predictive action, if the controller predicts that the driveline retarder is likely to cause a derating condition, the power curve it uses in the controller may be further reduced from its instantaneous power capacity to prevent the driveline retarder from entering a derated state, or to achieve the correct target gear and speed in a predictive manner to account for the impending driveline retarder derating.

If there are different braking torque/power output resolution retarders, a high resolution retarder is employed to assist the low resolution retarder so that the driveline delivers high resolution braking torque/power to achieve good vehicle speed control during downhill descent. For retarder devices controlled by their own control module, a speed/torque/power request (such as a J1939TSC1 message) is available to an Electronic Control Unit (ECU) that operates the PDSC.

During a torque interrupt transmission shift when engine braking power is lost. Any other retarding device, such as a driveline retarder or a vehicle foundation brake, may be used as a torque compensating device to compensate for engine retarding power lost during transmission shifts. Predictive information may be utilized such that the power of these retarders is preserved for use during the shift.

In some operating scenarios, the PDSC may face the risk of losing look-ahead data. The loss of look-ahead data may be abrupt (e.g., due to a GPS or navigation system failure) or gradual due to vehicle movement (e.g., the route between the two points may not be drawn). If look-ahead data is suddenly lost, the PDSC may be configured to take predictive action based only on the current look-ahead data. Past look-ahead data and decisions (prior to data loss) may be excluded. This is a conservative approach, assuming that past look-ahead data is not reliable enough and not worth relying on. In some embodiments, the PDSC may utilize past look-ahead data (prior to data loss) to make control decisions. If look-ahead data is gradually lost, the PDSC may use past look-ahead data (prior to the loss of data) to make control decisions.

In some operating scenarios, the PDSC may be faced with a vehicle speed sensor failure (e.g., transmission output shaft speed sensor failure or data loss). In such a scenario, the PDSC may utilize the engine speed and transmission gear number to determine the corresponding vehicle speed it uses. During a shift, the vehicle speed may be considered a constant.

In some operating scenarios, if the PDSC is faced with a look-ahead data loss, other sensors (such as cameras, lidar) may be used to provide a look-ahead grade and a posted speed limit. In one embodiment, the accuracy of look-ahead data may be improved with fusion of cloud-based look-ahead devices e-horizons, cameras, lidars, road grade sensors.

In another aspect, the PDSC may perform an adaptive action to adjust its parameters, such as redundancy coefficients of the engine braking torque curve, based on actions performed by the PDSC in response to the feedback mechanism. The engine braking torque curve may take into account the effects of altitude, where engine braking capacity is limited relative to nominal conditions. The PDSC may implement its predictive algorithm using a model of derating of the engine brake torque curve using ambient air pressure.

In another aspect, the PDSC may take into account the effects of traffic (including surrounding vehicles, traffic lights, and signpost speed limits) using vehicle-to-X (V2X) communications to determine and use as input to the feature an effective signpost speed limit. In one embodiment, the suggested speed may be considered part of the determination of an effective indicated speed limit. Other information, such as weather (rain, snow, wind) and other information of the road (e.g., road curvature) may be used to determine vehicle dynamics parameters and effective marking speed limits, taking into account the effects of these factors. In one embodiment, icing or wet road conditions may be used to optimize the vehicle deceleration process to avoid events such as folding, for example, if a following vehicle loses look ahead, the preceding vehicle may provide/supplement electronic horizon information through vehicle-to-vehicle (V2V) communication. While all of the main calculations of the features may be performed within the ECU, some additional high-level heavy calculations may be performed on the cloud and communicate information to the ECU.

In further aspects, the PDSC determines its mode of operation (e.g., disabled, inactive, active, derated, and failure mode), and the PDSC communicates its mode, speed target, and transmission gear request for display on the vehicle dashboard. An example of derating mode is when look-ahead data is not available and the PDSC only uses its feedback mechanism to protect the vehicle. In another example, the configuration match between the ECU with PDSC and the e-horizons may be a digital validation process to ensure that the look-ahead parameters are present. If not, the PDSC may be set to a fault or inactive mode to alert the driver. Alternatively, the PDSC may automatically activate the emergency alert/hazard lights.

The vehicle quality estimator (MME) and Vehicle Parameter Determination (VPD) features may be used for predictive algorithms in the PDSC. As used herein, VPD is a feature that determines all power loss of a vehicle, including rolling friction loss, aerodynamic loss, and driveline loss. Different sensors may be used to improve these estimates, such as torque sensors, wind sensors, cameras (for detecting the road surface, and thus modeling rolling resistance), balloon pressure sensors (estimating the mass of the vehicle acting on the axle). The measurements of these sensors may be fused with the current production sensors for these features to improve the predictive algorithm in the ECU.

Referring to fig. 4, a flowchart of an exemplary procedure 300 is shown for adjusting the speed of the vehicle 100 toward a target speed and shifting the transmission 106 prior to or upon reaching a downhill segment of the route, such as the downhill segment 204, in addition to dynamically adjusting the vehicle speed and transmission gear as the vehicle travels along the downhill segment 204.

The routine 300 begins at operation 302, where in operation 302, a control routine is initiated to control vehicle speed and shift the transmission prior to the downhill segment 204 in response to a target speed of the vehicle 100 and a target gear of the transmission 106. As discussed above, the target speed may be determined based on the look-ahead road grade and the speed limit of the downhill road segment 204.

Operation 302 may begin by resolving a firing event, completion of a cycle, restarting the procedure 300, by initiating a vehicle operation (such as a reverse towing condition), or by initiation by a vehicle operator or technician. As used herein, a counter-drag condition is an operating condition in which the engine 104 does not require fuel to propel the vehicle 100, such as when the throttle is closed, the accelerator pedal 145 is raised, the accelerator pedal 145 is in a dead zone in which fuel is not required, and/or when the accelerator pedal 145 is not depressed.

From operation 302, the process 300 continues to operation 304. Operation 304 includes monitoring look-ahead conditions along the route 202, such as approaching route grade, road slope, grade length, and vehicle speed limits, to name a few. It is contemplated that in certain embodiments, the look-ahead condition may include a road grade and speed limit for the entire route 202. In other embodiments, the look-ahead condition is for a portion of the route ahead of the downhill road segment 204, the downhill road segment, and ahead of the downhill road segment, for all of which the program 300 will be used to control vehicle speed.

From operation 304, the process 300 continues to operation 306 to determine a look-ahead road grade and speed limit. Subsequently, operation 308 includes determining a look-ahead terminal speed and a transmission gear. Thereafter, operation 310 includes determining a look-ahead target speed and a transmission gear. The terminal speed and transmission gear, as well as the target speed and transmission gear, may be determined in response to vehicle configuration, vehicle mass, road slope, and other conditions, as discussed above. The terminal speed and transmission gear, as well as the target speed and transmission gear, may be updated continuously along the route during operation of the vehicle 100 or periodically in response to input of operating parameters into the ECS.

The process 300 continues to condition 312 to determine if any pre-downhill actions are required as the vehicle approaches the downhill segment of the route 202. If the condition 312 is negative, the process 300 continues to operation 304 to continue monitoring for a look-ahead condition along the route 202. If conditional 312 is yes, indicating that an action is required, then procedure 300 continues from conditional 312 to operation 314.

The routine 300 executes operation 314 to select and then control to the pre-downhill target vehicle speed and the pre-downhill target transmission gear. In one embodiment, the pre-downhill target vehicle speed and the pre-downhill target transmission gear are selected before or upon the vehicle reaching a downhill segment. In one embodiment, a target transmission gear is selected to transition the vehicle to a desired pre-downhill speed and to provide a gear configured to assist in maintaining the desired downhill vehicle speed.

From operation 314, the process 300 continues to operation 316, where at operation 316, the vehicle speed is controlled as the vehicle 100 travels along the downhill path 204. In one embodiment, one or more components of the vehicle powertrain may be controlled during a downhill road segment to reduce or maintain vehicle speed to meet a downhill vehicle speed limit. In another embodiment, operation of the driveline retarder to reduce or maintain vehicle/engine speed during a downhill path without applying a foundation brake may be controlled to meet a downhill vehicle speed limit. In another embodiment, the transmission may be downshifted to a lower gear during a downhill path to reduce or maintain vehicle/engine speed to meet a downhill speed limit. In yet another embodiment, the foundation brake may be operated during a downhill path to reduce or maintain vehicle/engine speed to meet the downhill speed limit.

From operation 316, the process 300 continues to operation 318 to continue monitoring for a look-ahead condition along the route 202. From operation 318, the routine 300 continues to operation 320 to determine a coasting transition target speed and transmission gear. In one embodiment, the coasting transition target speed may be determined in response to a first indicated speed limit for a portion of a downhill road segment and a second indicated speed limit for a road segment that is forward or ahead of the portion of the downhill road segment. From operation 320, the process 300 continues to condition 322 to determine whether the vehicle is approaching the end of a downhill segment of the route 202 and whether a hill slide transition maneuver is required. If condition 322 is false, then the process 300 continues to operation 318 to continue monitoring for a look-ahead condition along the route 202. If condition 322 is yes, indicating that the end of the downhill segment of route 202 is approaching and that a hill slide transition action may be performed, then routine 300 continues to operation 324.

The routine 300 executes operation 324, where at operation 324, the vehicle is controlled to accelerate toward a coasting transition target speed when the vehicle reaches the portion of the downhill segment of the route 202. From operation 324, the process 300 continues to condition 326 to determine whether the end of the downhill slope has been reached. If condition 326 is false, then routine 300 continues to operation 324 to continue accelerating along route 202 to a taxi transition target speed. If the condition 326 is yes, indicating that the end of the downhill segment of the route 202 is reached, the process 300 continues to operation 328. The program performs operation 328 to transition the PDSC to the inactive state. The process 300 then completes and ends at operation 330, where the process 300 may be restarted, as discussed above with respect to operation 302.

The present disclosure provides an advanced look-ahead control feature that electronically controls the vehicle by selecting the best driveline decisions (particularly for the engine, transmission, foundation brake, and other retarders) as the vehicle traverses steep grades, thereby ensuring a safe and controllable grade.

Various aspects of the present disclosure are contemplated. According to one aspect, a vehicle system is provided that includes a powertrain including a prime mover and a transmission coupled to the prime mover, one or more driveline retarders, one or more ground engaging wheels coupled to the transmission, the one or more ground engaging wheels being drivable by the prime mover through the transmission, a foundation brake actuatable to slow the one or more ground engaging wheels, and an electronic control system in operative communication with the prime mover, the transmission, and the foundation brake.

Referring to fig. 5, a diagram depicting certain aspects of a software architecture 400 in a VSM control unit 150 configured to control various operational aspects of the vehicle 100 is shown. For example, the software architecture 400 may be configured to receive input 402 including look-ahead data including road grade or grade and posted speed limits, as well as other vehicle operating parameters. The software architecture 400 may also include a processor for performing diagnostics 404 to predict vehicle speed before reaching a downhill road segment based on look-ahead data and vehicle operating parameters. In some aspects, the predicted speed and gear module 406 may be configured to determine a plurality of operational aspects of the vehicle 100, including a target look-ahead gear and vehicle speed, a predicted gear and vehicle speed to achieve the target gear and speed by an engine retarder, and a predicted gear and vehicle speed to achieve a highest gear by engine reverse. Further, performing diagnostics 404 based on the look-ahead data and the vehicle operating parameters may be used to determine a status of the vehicle 100 prior to, immediately prior to, or on the downhill road segment. In some aspects, the state determination module 408 may be configured to consider downshifts based on vehicle and/or engine speed feedback, determine a feedback-based target transmission gear and vehicle speed, a base brake request enabler based on vehicle and/or engine speed feedback, state determination, and mode determination. In some aspects, the predicted speed and gear module 406 may use the estimated foundation brake temperature in the foundation brake temperature module 410 to determine the target look-ahead gear and the vehicle speed. In certain aspects, the software architecture 400 may consider the driver intervention 412, for example, when the vehicle driver wants to manually reduce the vehicle speed or manually downshift. The software architecture 400 may be configured to determine one or more actions in response to calculations from the state determination module 408, the driver intervention 412, or other user inputs. The determine action module 414 may be configured to perform actions including issuing a gear number request/neutral coast request to the TCU 140, issuing a vehicle speed target to retarder control and road speed limiter, an engine anti-tug request, and an XBR deceleration request to the foundation brake controller. In some aspects, the determination action module 414 may use the foundation brake temperature estimated in the foundation brake temperature module 410.

In accordance with the above embodiments, the present disclosure provides dynamic speed control features for vehicles traveling along a flat or ramp route. In some embodiments, the feature automatically determines a target transmission gear and a target vehicle speed within a look-ahead range based on the look-ahead grade and speed limit data. The calculations are applicable to downhill and normal flat roads to account for speed limit changes for both accelerator-based driving and cruise control modes.

In one embodiment, the dynamic speed control feature determines when to begin taking action to progressively reduce the vehicle speed and/or downshift the transmission to achieve the target transmission gear and the target vehicle speed depending on a calibratable margin of distance to the downhill or a new speed limit. During this preliminary configuration process, the feature takes corrective action based on the updated predictions, slowing down the process or applying the foundation brakes of the vehicle to progressively slow down more quickly, if necessary. During a preliminary configuration in which the vehicle is still on a flat road and the target gear and target speed have been reached, the feature may execute an emulation cruise control mode to automatically fuel the vehicle to maintain the target speed on the remaining road segments ahead of the downhill.

In one embodiment, the dynamic speed control feature automatically controls the foundation brake by braking the bump-stop if it is determined that the current transmission gear and vehicle or engine speed are unsafe due to a downhill grade or vehicle or engine speed being above a commanded speed limit or maximum acceptable engine speed. Subsequently, the feature automatically performs a downshift action after taking a foundation braking action resulting in a reduction in engine speed to allow the downshift. The foundation brake temperature may be used to optimize the use of the foundation brake. Foundation brakes may be used as torque compensating devices during transmission shifts to maintain vehicle speed while descending a hill.

In one embodiment, the dynamic speed control feature automatically controls the engine brake, transmission, other retarder, and foundation brake to ensure safe downhill travel of the vehicle even in the event of complete loss of look-ahead data.

In one embodiment, the feature allows the driver to further reduce the vehicle speed from a safe speed via a foundation brake pedal or manual downshift if the driver is willing. In this regard, the feature prevents an inexperienced driver from increasing the vehicle speed beyond a safe downhill speed.

In another embodiment, the feature performs a hill coasting transition action by utilizing the grade of the end of the downhill segment to perform a reverse, neutral coast to meet the indicated speed limit requirement, improve fuel economy, and improve drivability.

In one embodiment, the features are coordinated with a driveline retarder and/or other retarder devices of the engine, driveline, and vehicle to optimize integrated driveline performance for applications where other retarder devices are still needed.

In another embodiment, the feature provides a warning to the driver via the dashboard of the vehicle when derated or faulty modes occur, in addition to maximizing the protective capabilities of the feature during these modes.

According to another aspect of the present disclosure, a controller is provided that is configured to perform any of the control techniques and methods described herein.

As shown in this detailed description, the present disclosure contemplates a number and variety of embodiments, including but not limited to the following exemplary embodiments.

Exemplary embodiment 1 is a vehicle system comprising a powertrain including a prime mover and a transmission coupled to the prime mover, one or more ground engaging wheels coupled to the transmission and drivable by the prime mover through the transmission, a foundation brake actuatable to slow the one or more ground engaging wheels, and an electronic control system in operative communication with the prime mover, the transmission and the foundation brake, the electronic control system configured to determine a pre-downgrade target vehicle speed of the vehicle, a pre-downgrade target transmission gear, and a pre-downgrade vehicle speed limit for the vehicle prior to or upon reaching the downgrade, control the vehicle to reach the pre-downgrade target vehicle speed and the pre-downgrade target transmission gear for the vehicle, and control the vehicle not to exceed the pre-downgrade vehicle speed limit during the downgrade.

Exemplary embodiment 2 includes the features of exemplary embodiment 1, wherein the electronic control system is configured to first control one or more components of the driveline to provide at least one of controlling a speed of the vehicle and maintaining the speed of the vehicle without applying the foundation brake prior to the downhill path.

Exemplary embodiment 3 includes the features of exemplary embodiment 2, wherein the driveline includes an engine, and the maintaining the speed of the vehicle includes fueling the engine to maintain the speed of the vehicle.

Exemplary embodiment 4 includes the features of exemplary embodiment 2, wherein the electronic control system is configured to operate the foundation brake for one of controlling a speed of the vehicle and maintaining the speed of the vehicle, prior to the downhill road segment, in response to determining that the first control is ineffective for reaching the pre-downhill target vehicle speed.

Exemplary embodiment 5 includes the features of exemplary embodiment 2, wherein the electronic control system is configured to at least one of operate a driveline retarder and downshift the transmission to a lower gear prior to the downhill path to facilitate at least one of the controlling the speed of the vehicle and the maintaining the speed of the vehicle.

Exemplary embodiment 6 includes the features of exemplary embodiment 2 wherein the electronic control system is configured to one of operate the foundation brake to facilitate at least one of the controlling the speed of the vehicle and the maintaining the speed of the vehicle during the downhill path and during the transmission downshift, and operate the foundation brake to facilitate at least one of the controlling the speed of the vehicle and the maintaining the speed of the vehicle before the downhill path and during the transmission downshift.

Exemplary embodiment 7 includes the features of exemplary embodiment 1 wherein the electronic control system is configured to determine a coasting transition target speed of the vehicle on a portion of the downhill road segment and control the vehicle to accelerate toward the coasting transition target speed when the vehicle reaches the portion of the downhill road segment.

Exemplary embodiment 8 includes the features of exemplary embodiment 7 wherein the coasting transition target speed is determined in response to one of a first speed limit for the portion of the downhill road segment and a second speed limit for a forward segment ahead of the portion of the downhill road segment.

Example embodiment 9 includes the features of example embodiment 7, wherein the electronic control system is configured to control the vehicle to accelerate toward the coasting transition target speed when the vehicle reaches the portion of the downhill road segment by one of engine off coasting, neutral coasting, and reverse-towing in combination with transmission upshifting to optimize engine reverse-towing friction.

Exemplary embodiment 10 includes the features of exemplary embodiment 1, wherein the electronic control system is configured to at least one of operate a driveline retarder to supplement the driver operation, reduce the downhill vehicle speed limit, and reduce the pre-downhill target vehicle speed in response to driver operation of the foundation brake.

Exemplary embodiment 11 includes the features of exemplary embodiment 1 wherein the electronic control system is configured to one of first attempt to control the vehicle speed to the pre-downhill target vehicle speed by operating the foundation brake in conjunction with a driveline retarder, second attempt to control the vehicle speed to the pre-downhill target vehicle speed by operating the foundation brake in conjunction with a transmission shift if the first attempt is unsuccessful, first attempt to control or maintain the vehicle speed below the downhill vehicle speed limit by operating the foundation brake in conjunction with the driveline retarder, second attempt to control or maintain the vehicle speed below the downhill vehicle speed limit by operating the foundation brake in conjunction with a transmission shift if the first attempt is unsuccessful, and supplement the driveline retarder with the foundation brake to reach the downhill vehicle speed limit.

Exemplary embodiment 12 is a method that includes operating a vehicle including a prime mover in a reverse towing condition, the vehicle including a transmission coupled to the prime mover, one or more ground engaging wheels coupled to the transmission and drivable by the prime mover through the transmission, and a foundation brake actuatable to slow the one or more ground engaging wheels, determining a pre-downhill target vehicle speed, a pre-downhill target transmission gear, and a downhill vehicle speed limit for the vehicle prior to reaching a downhill road segment, controlling the vehicle to reach the pre-downhill target vehicle speed and the pre-downhill target transmission gear for the vehicle prior to or upon reaching the downhill road segment, and controlling the vehicle not to exceed the downhill vehicle speed limit during the downhill road segment.

Exemplary embodiment 13 includes the features of exemplary embodiment 12 including, prior to the downhill path, first controlling one or more components of the driveline to provide at least one of controlling a speed of the vehicle and maintaining the speed of the vehicle without applying the foundation brake.

Exemplary embodiment 14 includes the features of exemplary embodiment 13, wherein the driveline includes an engine, and the maintaining the speed of the vehicle includes fueling the engine to maintain the speed of the vehicle.

Exemplary embodiment 15 includes the features of exemplary embodiment 13 including, prior to the downhill road segment, in response to determining that the first control is not effective to achieve the pre-downhill target vehicle speed, operating the foundation brake for one of controlling the speed of the vehicle and maintaining the speed of the vehicle.

Exemplary embodiment 16 includes the features of exemplary embodiment 13 including at least one of operating a driveline retarder and downshifting the transmission to a lower gear prior to the downhill path to facilitate at least one of controlling a speed of the vehicle and maintaining the speed of the vehicle.

Exemplary embodiment 17 includes the features of exemplary embodiment 13 including one of operating the foundation brake to facilitate at least one of the controlling the speed of the vehicle and the maintaining the speed of the vehicle during the downhill path and during the transmission downshift, and operating the foundation brake to facilitate at least one of the controlling the speed of the vehicle and the maintaining the speed of the vehicle prior to the downhill path and during the transmission downshift.

Exemplary embodiment 18 includes the features of exemplary embodiment 12 including determining a coasting transition target speed of the vehicle on a portion of the downhill road segment and controlling the vehicle to accelerate toward the coasting transition target speed when the vehicle reaches the portion of the downhill road segment.

Exemplary embodiment 19 includes the features of exemplary embodiment 18 wherein the coasting transition target speed is determined in response to one of a first speed limit for the portion of the downhill road segment and a second speed limit for a forward segment ahead of the portion of the downhill road segment.

Exemplary embodiment 20 includes the features of exemplary embodiment 18 including controlling acceleration of the vehicle toward the coasting transition target speed when the vehicle reaches the portion of the downhill path by one of engine off coasting, neutral coasting, and reverse-to-transmission upshift in combination to optimize engine reverse friction.

Exemplary embodiment 21 includes the features of exemplary embodiment 12 including at least one of operating a driveline retarder to supplement the driver operation, reducing the downhill vehicle speed limit, and reducing the pre-downhill target vehicle speed in response to driver operation of the foundation brake.

Exemplary embodiment 22 includes the features of exemplary embodiment 12 including one of first attempting to control vehicle speed to the pre-downhill target vehicle speed by operating the foundation brake in conjunction with a driveline retarder, second, if the first attempt is unsuccessful, operating the foundation brake in conjunction with a transmission shift to control vehicle speed to the pre-downhill target vehicle speed, first attempting to control or maintain vehicle speed below the downhill vehicle speed limit by operating the foundation brake in conjunction with the driveline retarder, second, if the first attempt is unsuccessful, operating the foundation brake in conjunction with a transmission shift to control or maintain vehicle speed below the downhill vehicle speed limit, and operating an electronic control system to supplement the driveline retarder with the foundation brake to reach the downhill vehicle speed limit.

Exemplary embodiment 23 is a controller device configured to perform the method of any of exemplary embodiments 12 to 22.

While illustrative embodiments of the disclosure have 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 illustrative embodiments have been shown and described and that all changes and modifications that come within the spirit of the claimed invention are desired to be protected. It should be understood that while the use of words such as preferable, preferred or more preferred utilized in the above description indicates 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 the claims be limited to only one item when words such as "a," "an," "at least one," or "at least a portion" are used unless specifically stated to the contrary in the claims. When the language "at least a portion" and/or "a portion" is used, an item may include a portion and/or the entire item unless specifically stated to the contrary.

Claims (22)

1. A vehicle system, comprising:

a drivetrain comprising a prime mover and a transmission coupled to the prime mover;

one or more ground engaging wheels coupled to the transmission and drivable by the prime mover through the transmission;

A foundation brake actuatable to slow the one or more ground engaging wheels, and

An electronic control system in operative communication with the prime mover, the transmission, and the foundation brake, the electronic control system configured to:

Determining a pre-downhill target vehicle speed, a pre-downhill target transmission gear, and a downhill vehicle speed limit of the vehicle before reaching a downhill road segment;

controlling the vehicle to reach the pre-downhill target vehicle speed and the pre-downhill target transmission gear of the vehicle before or upon reaching the downhill road section, and

The vehicle is controlled not to exceed the downhill vehicle speed limit during the downhill road segment.

2. The vehicle system of claim 1, wherein the electronic control system is further configured to:

Prior to the downhill path, one or more components of the driveline are first controlled to provide at least one of controlling a speed of the vehicle and maintaining the speed of the vehicle without applying the foundation brake.

3. The vehicle system of claim 2, wherein the powertrain includes an engine and the maintaining the speed of the vehicle includes fueling the engine to maintain the speed of the vehicle.

4. The vehicle system of claim 2, wherein the electronic control system is configured to operate the foundation brake for one of controlling a speed of the vehicle and maintaining the speed of the vehicle prior to the downhill road segment in response to determining that the first control is ineffective for reaching the pre-downhill target vehicle speed.

5. The vehicle system of claim 2, wherein the electronic control system is further configured to:

at least one of operating a driveline retarder and downshifting the transmission to a lower gear prior to the downhill path to facilitate at least one of controlling a speed of the vehicle and maintaining the speed of the vehicle.

6. The vehicle system of claim 2, wherein the electronic control system is further configured to one of:

operating the foundation brake to facilitate at least one of said controlling a speed of the vehicle and said maintaining a speed of the vehicle during the downhill path and during the transmission downshift, and

The foundation brake is operated to facilitate at least one of said controlling a speed of the vehicle and said maintaining a speed of the vehicle prior to the downhill path and during the transmission downshift.

7. The vehicle system of claim 1, wherein the electronic control system is further configured to:

Determining a coasting transition target speed of the vehicle on a portion of the downhill path, and

And controlling the vehicle to accelerate towards the coasting transition target speed when the vehicle reaches the part of the downhill road section.

8. The vehicle system of claim 7, wherein the coasting transition target speed is determined in response to one of a first speed limit of the portion of the downhill road segment and a second speed limit of a forward segment forward of the portion of the downhill road segment.

9. The vehicle system of claim 7, wherein the electronic control system is configured to control acceleration of the vehicle toward the coasting transition target speed when the vehicle reaches the portion of the downhill road segment by one of engine off coasting, neutral coasting, and reverse-to-reverse combined with transmission upshift to optimize engine reverse-to-friction.

10. The vehicle system according to claim 1, wherein the electronic control system is configured to respond to the base driver operation of the brake to at least one of:

operating a driveline retarder to supplement the driver operation,

Reducing the downhill vehicle speed limit, and

And reducing the speed of the target vehicle before the downhill slope.

11. The vehicle system of claim 1, wherein the electronic control system is further configured to one of:

First attempting to control the vehicle speed to the pre-downhill target vehicle speed by operating the foundation brake in conjunction with a driveline retarder, second, if the first attempt is unsuccessful, operating the foundation brake in conjunction with a transmission shift to control the vehicle speed to the pre-downhill target vehicle speed;

firstly attempting to control or maintain vehicle speed below the downhill vehicle speed limit by operating the foundation brake in conjunction with the driveline retarder, secondly, if the first attempt is unsuccessful, operating the foundation brake in conjunction with a transmission shift to control or maintain vehicle speed below the downhill vehicle speed limit, and

The foundation brake is used to supplement the driveline retarder to reach the downhill vehicle speed limit.

12. A method, comprising:

Operating a vehicle including a prime mover in a reverse towing condition, the vehicle including a transmission coupled to the prime mover, one or more ground engaging wheels coupled to the transmission and drivable by the prime mover through the transmission, and a foundation brake actuatable to slow the one or more ground engaging wheels;

Determining a pre-downhill target vehicle speed, a pre-downhill target transmission gear, and a downhill vehicle speed limit of the vehicle before reaching a downhill road segment;

controlling the vehicle to reach the pre-downhill target vehicle speed and the pre-downhill target transmission gear of the vehicle before or upon reaching the downhill road section, and

The vehicle is controlled not to exceed the downhill vehicle speed limit during the downhill road segment.

13. The method as claimed in claim 12, comprising:

Prior to the downhill path, one or more components of the driveline are first controlled to provide at least one of controlling a speed of the vehicle and maintaining the speed of the vehicle without applying the foundation brake.

14. The method of claim 13, wherein the powertrain includes an engine and the maintaining the speed of the vehicle includes fueling the engine to maintain the speed of the vehicle.

15. The method of claim 13, comprising, prior to the downhill road segment, operating the foundation brake for one of controlling a speed of the vehicle and maintaining the speed of the vehicle in response to determining that the first control is not effective to achieve the pre-downhill target vehicle speed.

16. The method as claimed in claim 13, comprising:

at least one of operating a driveline retarder and downshifting the transmission to a lower gear prior to the downhill path to facilitate at least one of controlling a speed of the vehicle and maintaining the speed of the vehicle.

17. The method of claim 13, comprising one of:

operating the foundation brake to facilitate at least one of said controlling a speed of the vehicle and said maintaining a speed of the vehicle during the downhill path and during the transmission downshift, and

The foundation brake is operated to facilitate at least one of said controlling a speed of the vehicle and said maintaining a speed of the vehicle prior to the downhill path and during the transmission downshift.

18. The method as claimed in claim 12, comprising:

Determining a coasting transition target speed of the vehicle on a portion of the downhill path, and

And controlling the vehicle to accelerate towards the coasting transition target speed when the vehicle reaches the part of the downhill road section.

19. The method of claim 18, wherein the coasting transition target speed is determined in response to one of a first speed limit for the portion of the downhill road segment and a second speed limit for a forward segment ahead of the portion of the downhill road segment.

20. The method of claim 18, comprising controlling acceleration of the vehicle toward the coasting transition target speed when the vehicle reaches the portion of the downhill path by one of engine off coasting, neutral coasting, and reverse towing in combination with transmission upshifting to optimize engine reverse towing friction.

21. The method of claim 12, comprising at least one of the following in response to a driver operation of the foundation brake:

operating a driveline retarder to supplement the driver operation,

Reducing the downhill vehicle speed limit, and

And reducing the speed of the target vehicle before the downhill slope.

22. The method of claim 12, comprising one of:

Firstly attempting to control the vehicle speed to said pre-downhill target vehicle speed by operating said foundation brake in combination with a driveline retarder, secondly, if said first attempt is unsuccessful, operating the foundation brake in combination with a transmission shift to control the vehicle speed to said pre-downhill target vehicle speed, and

Firstly attempting to control or maintain vehicle speed below the downhill vehicle speed limit by operating the foundation brake in conjunction with the driveline retarder, secondly, if the first attempt is unsuccessful, operating the foundation brake in conjunction with a transmission shift to control or maintain vehicle speed below the downhill vehicle speed limit, and

The electronic control system is operated to supplement the driveline retarder with a foundation brake to reach a downhill vehicle speed limit.