BACKGROUND

Field

Without limitation to a particular field of technology, the present disclosure is directed to transmissions configured for coupling to a prime mover, and more particularly to transmissions for vehicle applications, including truck applications.

Transmissions serve a critical function in translating power provided by a prime mover to a final load. The transmission serves to provide speed ratio changing between the prime mover output (e.g. a rotating shaft) and a load driving input (e.g. a rotating shaft coupled to wheels, a pump, or other device responsive to the driving shaft). The ability to provide selectable speed ratios allows the transmission to amplify torque, keep the prime mover and load speeds within ranges desired for those devices, and to selectively disconnect the prime mover from the load at certain operating conditions.

Transmissions are subjected to a number of conflicting constraints and operating requirements. For example, the transmission must be able to provide the desired range of torque multiplication while still handling the input torque requirements of the system. Additionally, from the view of the overall system, the transmission represents an overhead device—the space occupied by the transmission, the weight, and interface requirements of the transmission are all overhead aspects to the designer of the system. Transmission systems are highly complex, and they take a long time to design, integrate, and test; accordingly, the transmission is also often required to meet the expectations of the system integrator relative to previous or historical transmissions. For example, a reduction of the space occupied by a transmission may be desirable in the long run, but for a given system design it may be more desirable that an occupied space be identical to a previous generation transmission, or as close as possible.

Previously known transmission systems suffer from one or more drawbacks within a system as described following. To manage noise, robustness, and structural integrity concerns, previously known high output transmission systems use steel for the housing of the transmission. Additionally, previously known high output transmissions utilize a large countershaft with high strength spur gears to manage the high loads through the transmission. Previously known gear sets have relatively few design degrees of freedom, meaning that any shortcomings in the design need to be taken up in the surrounding transmission elements. For example, thrust loads through the transmission, noise generated by gears, and installation issues such as complex gear timing issues, require a robust and potentially overdesigned system in the housing, bearings, and/or installation procedures. Previously known high output transmissions, such as for trucks, typically include multiple interfaces to the surrounding system (e.g. electrical, air, hydraulic, and/or coolant), each one requiring expense of design and integration, and each introducing a failure point into the system. Previously known high output transmissions include a cooler to protect the parts and fluids of the transmission from overheating in response to the heat generated in the transmission. Previously known high output transmissions utilize concentric clutches which require complex actuation and service. Accordingly, there remains a need for improvements in the design of high output transmissions, particularly truck transmissions.

SUMMARY

An example transmission includes an input shaft configured to couple to a prime mover, a countershaft having a first number of gears mounted thereon, a main shaft having a second number of gears mounted thereon, a shifting actuator that selectively couples the input shaft to the main shaft by rotatably coupling at least one of the first number of gears to the countershaft and/or coupling the second number of gears to the main shaft, where the shifting actuator is mounted on an exterior wall of a housing, and where the countershaft and the main shaft are at least partially positioned within the housing.

Certain further embodiments of an example transmission are described following. An example transmission includes an integrated actuator housing, where the shifting actuator is operationally coupled to the integrated actuator housing, and where the shifting actuator is accessible by removing the integrated actuator housing; a number of shifting actuators operationally coupled to the integrated housing actuator, where the number of shifting actuators are accessible by removing the integrated actuator housing; where the shifting actuator is mechanically coupled to the integrated actuator housing; and/or where a number of shifting actuators are mechanically coupled to the integrated housing actuator. An example transmission includes a clutch actuator accessible by removing the integrated actuator housing; where the clutch actuator is a linear clutch actuator; the example transmission further including a clutch actuator housing; where the linear clutch actuator is positioned at least partially within the clutch actuator housing; and where the clutch actuator housing coupled to the integrated actuator housing and/or included as a portion of the integrated actuator housing; where the integrated housing actuator includes a single external power access, and/or where the single external power access includes an air supply port. An example transmission includes the integrated actuator housing defining power connections between actuators operationally coupled to the integrated actuator housing; where the integrated actuator housing is mounted on a vertically upper side of the transmission; where the shifting actuators are accessible without decoupling the input shaft from the prime mover; where the integrated actuator housing is accessible without decoupling the input shaft from the prime mover; where the linear clutch actuator is pneumatically activated; where the linear clutch actuator has a first extended position and a second retracted position, and where the linear clutch actuator includes a near zero dead air volume in the second retracted position; where the dead air volume includes an air volume on a supply side of the linear clutch actuator that is present when the linear clutch actuator is retracted; and/or where the linear clutch actuator has a first extended position and a second retracted position, and where the second retracted position is stable over a selected service life of a clutch operationally coupled to the linear clutch actuator.

An example transmission includes a driveline having an input shaft, a main shaft, and a countershaft that selectively couples the input shaft to the main shaft, a housing element with at least part of the driveline positioned in the housing, where the housing element includes aluminum, and where the transmission is a high output transmission. Certain further embodiments of an example transmission are described following. An example transmission includes the transmission having no cooler; where the countershaft selectively couples the input shaft to the main shaft using helical gear meshes, and/or where the helical gear meshes provide thrust management; where the housing does not takes thrust loads from the driveline; where the helical gear meshes further provide thrust management such that a bearing at a low speed differential position in the transmission takes thrust loads from the driveline; and/or where the bearing taking thrust at a low speed differential position is a bearing operationally coupled to the input shaft and the main shaft. An example transmission further includes a planetary gear assembly coupled to a second main shaft, where the planetary gear assembly includes helical gears; where the planetary gear assembly provides a thrust load in response to power transfer through the planetary gear assembly; where the first main shaft is rotationally coupled to the second main shaft; where the transmission does not include taper bearings in the driveline; where the countershaft is a high speed countershaft; where the transmission includes a number of high speed countershafts; and where a first gear ratio between the input shaft and the countershaft, a second gear ratio between the countershaft and the main shaft, have a ratio where the second gear ratio is greater than the first gear ratio by at least 1.25:1, at least 1.5:1, at least 1.75:1, at least 2:1, at least 2.25:1, at least 2.5:1, at least 2.75:1, at least 3:1, at least 3.25:1, at least 3.5:1, at least 3.75:1, at least 4:1, at least 4.25:1, at least 4.5:1, at least 4.75:1, at least 5:1, at least 6:1, at least 7:1, at least 8:1, at least 9:1, and/or at least 10:1.

An example transmission includes a driveline having an input shaft, a main shaft, and a countershaft that selectively couples the input shaft to the main shaft, and a low loss lubrication system. Certain further embodiments of an example transmission are described following. An example transmission includes the low loss lubrication system having a dry sump; the low loss lubrication system having a lubrication pump assembly positioned within the transmission; the low loss lubrication system including a lubrication pump rotationally coupled to the countershaft, and/or where the countershaft is a high speed countershaft; a lubrication sleeve positioned at least partially within the main shaft, and/or where the lubrication sleeve is an unsealed lubrication sleeve.

An example transmission includes a driveline having an input shaft, a main shaft, and a countershaft that selectively couples the input shaft to the main shaft, a countershaft that includes a number of gears mounted thereon, and a power take-off (PTO) access positioned in proximity to at least one of the number of gears. Certain further embodiments of an example transmission are described following. An example transmission includes the PTO access being an 8-bolt PTO access; the transmission including an aluminum housing; the transmission further having a first end engaging a prime mover and a second end having an output shaft, and a second PTO access positioned at the second end; where the transmission is an automated manual transmission; and/or a second countershaft, where the PTO access is positioned in proximity to the countershaft or the second countershaft.

An example transmission includes an input shaft configured to couple to a prime mover, a countershaft having a first number of gears mounted thereon, a main shaft having a second number of gears mounted thereon, where the first number of gears and the second number of gears are helical gears, and where the transmission is a high output transmission. Certain further embodiment of an example transmission are described following. An example transmission includes an aluminum housing, where the main shaft and the countershaft are at least partially positioned in the housing; a bearing pressed into the housing, where the helical gears manage thrust loads such that the bearing pressed into the housing does not experience thrust loads; where the first number of gears and second number of gears include a shortened tooth height and/or a flattened top geometry.

An example clutch assembly includes a clutch disc configured to engage a prime mover, a pressure plate having a clutch biasing element, where the clutch engagement member couples to a clutch actuation element at an engagement position, and where a clutch adjustment member maintains a consistent engagement position as a face of the clutch disc experiences wear. Certain further embodiments of an example clutch assembly are described following. An example clutch assembly includes the clutch adjustment member having a cam ring operable to rotate in response to clutch disc wear; a pressure plate defining the clutch biasing element and the clutch adjustment member; the pressure plate further defining access holes for the clutch adjustment member; the clutch assembly further including an anti-rotation member operationally coupled to the clutch adjustment member to enforce one-way movement of the clutch adjustment member; and/or the pressure plate further defining at least one access channel for the anti-rotation member.

Architectures for high output, high efficiency, low noise and otherwise improved automated transmissions are disclosed herein, including methods, systems, and components for automated truck transmissions. Such methods and systems may include, among other things, a pair of high speed, twin countershafts. Architectures for 18-speed (including 3×3×2 architectures with three gear boxes) and 12-speed (including 3×2×2 architectures with three gear boxes) are disclosed. In embodiments, such methods and systems include methods and systems for thrust load cancellation, including cancellation of loads across a helical or sun gear used in at least one gear box of the transmission. In embodiments, enclosures, such as for the clutch and various gears are configured such that enclosure bearings are isolated from thrust loads, among other things allowing for use of lightweight materials, such as die cast aluminum, for various components of the transmission, without compromising performance or durability. A low-loss lubrication system may be provided for various components of the transmission.

In embodiments, clutch actuation (including for a linear clutch actuator that may actuate movement of a use a horseshoe, or off-axis, clutch actuator) and gear shift actuation for an automated truck transmission are handled through an integrated electrical and mechanical assembly, which may be mounted in a mounted transmission module (MTM) on the transmission, and which may use a common, integrated air supply for pneumatic actuation of clutch and gear systems, optionally employing integrated conduits, rather than hoses, to reduce the free volume of air and thereby enhance the efficiency, reliability and performance of the gear and clutch actuation systems. The MTM may include a linear clutch actuator, position sensor and valve banks for gear and clutch actuation.

Gear systems, including substantially circular gears and helical gears, may be optimized to reduce noise and provide smooth shifting. Circular gears may have substantially flat teeth, may be wormwheel-ground to provide smooth surfaces, and may be provided with profiles optimized to provide optimized sliding velocity of engagement during gear shifts. The transmission may power power-take off (PTO) interfaces, optionally including multiple PTO interfaces.

An example method includes an operation to provide a first opposing pulse, the first opposing pulse including a first predetermined amount of air above an ambient amount of air in a first closed volume, where pressure in the first closed volume opposes movement of a shift actuator in a shift direction, an operation to provide a first actuating pulse, the first actuating pulse including a second predetermined amount of air above an ambient amount of air in a second closed volume, where pressure in the second closed volume promotes movement of the shift actuator in the shift direction, and an operation to release pressure in the first closed volume and the second closed volume in response to determining a shift completion event.

Certain further operations of the example method are described following, any one or more of which may be included in certain embodiments. The example method further includes: an operation to provide the first actuating pulse as two split pulses, where a first one of the two split pulses is smaller than a first one of the two pulses; where a second one of the two split pulses includes an amount of air substantially equal to the first predetermined amount of air; and/or where the first one of the two split pulses includes an amount such as: between one-tenth and one-fourth of a total amount of air provided by the two split pulses, less than 40% of a total amount of air provided by the two split pulses, less than 33% of a total amount of air provided by the two split pulses, less than 25% of a total amount of air provided by the two split pulses and/or less than 20% of a total amount of air provided by the two split pulses. The example method further includes: the first opposing pulse is performed at least 100 milliseconds (msec) before the first actuating pulse; the first actuating pulse is performed within a 200 msec window; an operation to determine that a synchronizer engagement is imminent, and to provide the first opposing pulse in response to the imminent synchronizer engagement; providing the second predetermined amount of air by determining the second predetermined amount of air in response to a velocity of a shift actuator and a target velocity of a shift actuator; an operation to determine that a synchronizer is in an unblocked condition, and to provide a second opposing pulse in response to the synchronizer being in the unblocked condition; where determining that a synchronizer is in an unblocked condition includes an operation such as: determining that a speed differential between engaging shafts is lower than an unblocking threshold value, determining that a speed differential between engaging shafts is within a predetermined unblocking range value, determining that a synchronizer engagement time value has elapsed, and/or determining that a shift actuator position value indicates the unblocking condition. The example method further includes: an operation to determine that a synchronizer is in an unblocked condition, and to provide a second opposing pulse in response to the synchronizer being in the unblocked condition; where determining that the synchronizer is in an unblocked condition includes at least one operation such as: determining that a speed differential between engaging shafts is lower than an unblocking threshold value, determining that a speed differential between engaging shafts is within a predetermined unblocking range value, determining that a synchronizer engagement time value has elapsed, and/or determining that a shift actuator position value indicates the unblocking condition. The example method further includes: where the first actuating pulse includes a pulse-width-modulated operation; an operation to determine a shift actuator position value, and to modify a duration of the first actuating pulse in response to the shift actuator position value; an operation to determine a shift actuator position value, and to modulate the first actuating pulse in response to the shift actuator position value; where the shift actuator position value includes at least one of: a quantitative position description of the shift actuator; a quantitative velocity description of the shift actuator; and/or a shift state description value corresponding to the shift actuator; where the shift state description value includes at least one of: a neutral position; a neutral departure position; a synchronizer engagement approach position; a synching position; a synchronizer unblock position; an engaged position; and/or a disengaging position.

Certain further operations of the example method are described following, any one or more of which may be included in certain embodiments. The example method further includes where the first actuating pulse includes a shaped air provision trajectory; where the first actuating pulse includes at least one operation to open and close a binary pneumatic valve; an operation to determine at least one shaft speed value, and to determine the predetermined first air amount in response to the at least one shaft speed value; an operation to determine an air supply pressure value, and to determine the predetermined first air amount in response to the air supply pressure value; an operation to determine at least one temperature value, and to determine the predetermined first air amount in response to the at least one temperature value; an operation to determine the predetermined first air amount in response to at least one of: at least one shaft speed value, an air supply pressure value, and/or at least one temperature value; an operation to determine at least one shaft speed value, and to determine a timing of the predetermined first air amount in response to the at least one shaft speed value; an operation to determine an air supply pressure value, and to determine a timing of the predetermined first air amount in response to the air supply pressure value; an operation to determine at least one temperature value, and to determine a timing of the predetermined first air amount in response to the at least one temperature value; an operation to determine a timing of the predetermined first air amount in response to at least one value such as: at least one shaft speed value, an air supply pressure value, and/or at least one temperature value; an operation to determine a reflected driveline inertia value, and to determine the predetermined first air amount in response to the reflected driveline inertia value; an operation to determine a reflected driveline inertia value, and to determine a timing of the predetermined first air amount in response to the reflected driveline inertia value; determining the predetermined first air amount in response to at least one value such as: at least one shaft speed value, an air supply pressure value, at least one temperature value, and/or a reflected driveline inertia value.

Certain further operations of the example method are described following, any one or more of which may be included in certain embodiments. An operation to determine a timing of the predetermined first air amount in response to at least one value such as: at least one shaft speed value, an air supply pressure value, at least one temperature value, and/or a reflected driveline inertia value; an operation to determine a shift actuator position value, and to adjust at least one of the first actuating pulse and the first opposing pulse in response to the shift actuator position value; where adjusting includes interrupting the first actuating pulse and/or the first opposing pulse to synchronize pressure decay in the first closed volume and the second closed volume; an operation to determine a shift actuator position value, and adjusting the first actuating pulse and/or the second opposing pulse in response to the shift actuator position value, and/or where adjusting includes interrupting the first actuating pulse and the second opposing pulse to synchronize pressure decay in the first closed volume and the second closed volume; where modulating the first actuation pulse includes reducing the second predetermined amount of air in response to the shift actuator position value being a shift state description value, and/or reducing the first actuating pulse in response to the shift state description value; where reducing the first actuating pulse includes limiting an air pressure build-up in the second closed volume; where first shift actuator position value includes a shift state description, and where modulating includes reducing the second predetermined amount of air in response to the shift state description indicating a synching position; where reducing the first actuating pulse includes limiting an air pressure build-up in the second closed volume; where providing the first actuating pulse is commenced before the providing the first opposing pulse is commenced.

Certain further operations of the example method are described following, any one or more of which may be included in certain embodiments. The example method further includes an operation to provide a third opposing pulse, the third opposing pulse including a third predetermined amount of air above an ambient amount of air in a third closed volume, where pressure in the third closed volume opposes movement of a second shift actuator in a shift direction, an operation to provide a second actuating pulse, the second actuating pulse including a fourth predetermined amount of air above an ambient amount of air in a fourth closed volume, where pressure in the fourth closed volume promotes movement of the second shift actuator in the shift direction, and an operation to release pressure in the third closed volume and the fourth closed volume in response to determining a second shift completion event; and/or where the first opposing pulse, the third opposing pulse, the first actuating pulse, and the second actuating pulse are performed such that not more than one actuating valve is open simultaneously.

Another example method includes an operation to engage a friction brake to a countershaft of a transmission, to track an engaged time of the friction brake, to determine a target release time for the friction brake, to determine a release delay for the friction brake in response to the engaged time, and to command a release of the friction brake in response to the release delay and the target release time.

Certain further aspects of the example method are described following, any one or more of which may be included in certain embodiments. The example method further includes determining the release delay by determining a pressure decay value in a friction brake actuation volume; where determining the pressure decay value includes an operation to determine a pressure in the friction brake actuation volume; where determining the pressure decay value includes utilizing a pre-determined relationship between engaged time and pressure decay in the friction brake actuation volume; an operation to determine a speed differential between the countershaft and an engaging shaft, and to determine the target release time further in response to the speed differential; where the engaging shaft includes at least one shaft such as: an output shaft, a main shaft, and/or an input shaft; an operation to determine a lumped driveline stiffness value, and to determine the target release time further in response to the lumped driveline stiffness value; an operation to determine a target gear ratio value, and to determine the target release time further in response to the target gear ratio value; an operation to determine a friction brake disengagement dynamic value, and to determine the target release time further in response to the friction brake disengagement dynamic value; an operation to determine a vehicle speed effect, and to determine the target release time further in response to the vehicle speed effect; where the vehicle speed effect includes at least one effect such as: a current vehicle speed, an estimated vehicle speed at a gear engagement time, a vehicle acceleration rate, and/or a vehicle deceleration rate.

An example apparatus includes a backlash indication circuit that identifies an imminent backlash crossing event at a first gear mesh, and a means for reducing engagement force experienced by the first gear mesh in response to the backlash crossing event. Certain non-limiting examples of the means for reducing engagement force experienced by the first gear mesh in response to the backlash crossing event are described following. An example means for reducing engagement force experienced by the first gear mesh further includes means for performing at least one operation such as: disengaging the first gear mesh during at least a portion of the backlash crossing event, disengaging a clutch during at least a portion of the backlash crossing event, and slipping a clutch during at least a portion of the backlash crossing event. An example apparatus includes the backlash indication circuit further identifying the imminent backlash crossing event by determining that a gear shift occurring at a second gear mesh is likely to induce the backlash crossing event at the first gear mesh, and where the means for reducing engagement force experienced by the first gear mesh further includes a means for disengaging the first gear mesh during at least of portion of the gear shift. An example apparatus includes the means for reducing engagement force experienced by the first gear mesh further including a first gear mesh pre-load circuit that provides a disengagement pulse command, where the apparatus further includes a shift actuator responsive to the disengagement pulse command; where the first gear mesh pre-load circuit further provides the disengagement pulse command before the backlash crossing event occurs; where the disengagement pulse command includes a fifth predetermined amount of air above an ambient amount of air in a fifth closed volume, and where pressure in the fifth closed volume promotes movement of the shift actuator in the disengagement direction; where the disengagement pulse command further includes a sixth predetermined amount of air above an ambient amount of air in a sixth closed volume, where pressure in the sixth closed volume opposes movement of the shift actuator in the disengagement direction; where the first gear pre-load circuit further determines the fifth predetermined amount of air and the sixth predetermined amount of air such that the shift actuator is urged into a neutral position in response to a release of engagement force; where the first gear pre-load circuit further provides the disengagement pulse command before a first backlash crossing of the backlash crossing event; and/or where the first gear pre-load circuit further provides the disengagement pulse command before a subsequent backlash crossing of the backlash crossing event. An example apparatus includes the backlash indication circuit further identifies the imminent backlash crossing event by performing at least one operation such as: determining that an imminent rotational direction of the first gear mesh in a transmission is an opposite rotational direction to an established rotational direction of the first gear mesh, determining that a speed change between a first shaft comprising gears on one side of the first gear mesh and a second shaft comprising gears on an opposing side of the first gear mesh is likely to induce the backlash crossing event, determining that a gear shift occurring at a second gear mesh is likely to induce the backlash crossing event at the first gear mesh, determining that a transmission input torque value is at an imminent zero crossing event, and/or determining that a vehicle operating condition is likely to induce the backlash crossing event.

An example system includes and/or interacts with a prime mover providing motive torque, and the system includes a torque transfer path operatively coupling the motive torque to drive wheels, the torque transfer path including: a clutch that selectively decouples the prime mover from an input shaft of the torque transfer path, where the input shaft is operationally downstream of the clutch; a first gear mesh and a second gear mesh, each gear mesh having an engaged and a neutral position, and where both gear meshes in the engaged position couple the input shaft to the drive wheels, and where either gear mesh in the neutral position decouples the input shaft from the drive wheels; a first shift actuator that selectively operates the first gear mesh between the engaged and neutral position; a second shift actuator that selectively operates the second gear mesh between the engaged and neutral position; and a controller including: a vehicle state circuit that interprets at least one vehicle operating condition; a neutral enforcement circuit that provides a first neutral command to the first shift actuator and a second neutral command to the second shift actuator, in response to the vehicle operating condition indicating that vehicle motion is not intended.

Certain example aspects of the example system are described following, any one or more of which may be included in certain embodiments. An example system further includes the at least one vehicle operation condition including at least one value such as: an engine crank state value, a gear selection value, a vehicle idling state value, and/or a clutch calibration state value; the vehicle state circuit further determining a vehicle stopped condition, and where the neutral enforcement circuit further provides the first neutral command and the second neutral command in response to the vehicle stopped condition;

the controller further including a shift rail actuator diagnostic circuit that diagnoses proper operation of at least one shift rail position sensor in response to a vehicle speed value; the vehicle state circuit further interpreting at least one failure condition, and providing a vehicle stopping distance mitigation value in response to the at least one failure condition; the controller further including a clutch override circuit that provides a forced clutch engagement command in response to the vehicle stopping distance mitigation value; where the clutch override circuit further provides a forced clutch engagement command in response to the vehicle stopping distance mitigation value, and further in response to at least one value such as: a motive torque value representative of the motive torque, an engine speed value representative of a speed of the prime mover, an accelerator position value representative of an accelerator pedal position, a service brake position value representative of a position of a service brake position, a vehicle speed value representative of a speed of the drive wheels, and/or a service brake diagnostic value.

Another example system includes a clutch that selectively decouples a prime mover from an input shaft of a transmission, a progressive actuator operationally coupled to the clutch, where a position of the progressive actuator corresponds to a position of the clutch, and a controller including: a clutch characterization circuit that interprets a clutch torque profile, the clutch torque profile providing a relation between a position of the clutch and a clutch torque value, a clutch control circuit that commands a position of the progressive actuator in response to a clutch torque reference value and the clutch torque profile, and where the clutch characterization circuit further interprets a position of the progressive actuator and an indicated clutch torque, and updates the clutch torque profile in response to the position of the progressive actuator and the indicated clutch torque.

Certain further aspects of the example system are described following, any one or more of which may be included in certain embodiments. An example system includes the clutch torque profile including a first clutch engagement position value, and where the clutch control circuit further utilizes the first clutch engagement position value as a maximum zero torque position; where the clutch characterization circuit further interprets the clutch torque profile by performing a clutch first engagement position test, the clutch first engagement position test including: determining that an input shaft speed is zero, the clutch control circuit positioning the clutch at the first engagement position value, and comparing an acceleration of the input shaft speed to a first expected acceleration value of the input shaft speed; the clutch characterization circuit further performing the clutch first engagement position test a number of times; the clutch first engagement position test further including a friction brake control circuit that commands a friction brake to bring the input shaft speed to zero; where the clutch torque profile includes a second clutch engagement position value, and wherein the clutch control circuit further utilizes the second clutch engagement position value as a minimum significant engagement torque position; where the clutch characterization circuit further interprets the clutch torque profile by performing a clutch second engagement position test, the clutch second engagement position test including: determining that an input shaft speed is zero, the clutch control circuit positioning the clutch at the second engagement position value, and comparing an acceleration of the input shaft speed to a second expected acceleration value of the input shaft speed; where the clutch characterization circuit further performs the clutch second engagement position test a number of times; where the clutch second engagement position test further includes a friction brake control circuit that commands a friction brake to bring the input shaft speed to zero; where the clutch torque profile includes a first clutch engagement position value and a second clutch engagement position value, and/or where the clutch control circuit further utilizes the first clutch engagement position value as a maximum zero torque position and utilizes the second clutch engagement position value as a minimum significant engagement torque position. An example system further includes the clutch torque profile further including a clutch torque curve including a number of clutch position values corresponding to a number of clutch torque values, where each of the clutch position values is greater than the second clutch engagement position value; where the clutch characterization circuit further interprets the clutch torque profile by performing a clutch second engagement position test, the clutch second engagement position test including determining that an input shaft speed is zero, the clutch control circuit positioning the clutch at the second engagement position value, and comparing an acceleration of the input shaft speed to a second expected acceleration value of the input shaft speed, and adjusting the clutch torque curve in response to a change in the clutch second engagement position; where the clutch characterization circuit further determines that the clutch is operating in a wear-through mode in response to at least one of the first engagement position value and the second engagement position value changing at a rate greater than a clutch wear-through rate value; and/or where the controller further includes a clutch wear circuit that determines a clutch wear value in response to a clutch temperature value, a clutch power throughput value, and/or a clutch slip condition, and where the clutch characterization circuit further updates the clutch torque profile in response to the clutch wear value.

An example method includes an operation to interpret a clutch temperature value, to interpret a clutch power throughput value, to interpret that a clutch is in a slip condition, and, in response to the clutch temperature value, the clutch power throughput value, and the clutch slip condition, to determine a clutch wear value.

Certain further operations for the example method are described following, any one or more of which may be included in certain embodiments. An example method includes determining the clutch wear value includes accumulating a clutch wear index, the clutch wear index determined in response to the clutch temperature value, the clutch power throughput value, and the clutch slip condition; determining that a clutch is in a wear-through mode in response to the clutch wear index exceeding a wear-through threshold value; providing a clutch diagnostic value in response to the clutch wear index; and/or where providing the clutch diagnostic value includes at least one operation such as: providing a clutch wear fault value, incrementing a clutch wear fault value, communicating the clutch diagnostic value to a data link, and/or providing the clutch diagnostic value to a non-transient memory location accessible to a service tool.

An example system includes a clutch that selectively decouples a prime mover from an input shaft of a transmission, a progressive actuator operationally coupled to the clutch, where a position of the progressive actuator corresponds to a position of the clutch, and a means for providing a consistent lock-up time of the clutch, the lock-up time comprising a time commencing with a clutch torque request time and ending with a clutch lock-up event. Certain non-limiting examples of the means for providing a consistent lock-up time of the clutch are described following. An example means for providing the consistent lock-up time of the clutch includes a controller having a clutch control circuit, where the clutch control circuit commands a position of the progressive actuator in response to a clutch torque reference value and the clutch torque profile to achieve the consistent lock-up time of the clutch; where the progressive actuator includes a linear clutch actuator; and/or where the linear clutch actuator includes a near zero dead air volume. An example means for providing the consistent lock-up time of the clutch further includes a controller having a launch characterization circuit, the launch characterization circuit structured to interpret at least one launch parameter such as: a vehicle grade value, a vehicle mass value, and/or a driveline configuration value; and/or where the driveline configuration value includes at least one value such as: a target engagement gear description, a reflected driveline inertia value, and/or a vehicle speed value. An example means for providing the consistent lock-up time of the clutch further includes a controller having a clutch control circuit, where the clutch control circuit commands a position of the progressive actuator in response to a clutch torque reference value, the clutch torque profile, and at least one launch parameter to achieve the consistent lock-up time of the clutch; and/or where the clutch control circuit further commands the position of the progressive actuator in response to a clutch slip feedback value. An example means for providing the consistent lock-up time of the clutch further includes a controller having a clutch control circuit, where the clutch control circuit commands a position of the progressive actuator in response to a clutch torque reference value, the clutch torque profile, and/or a clutch slip feedback value. An example system further includes the clutch torque request time including at least one request condition such as: a service brake pedal release event, a service brake pedal decrease event, a gear engagement request event, and/or a prime mover torque increase event; and/or where the clutch lock-up event includes a clutch slip value being lower than a clutch lock-up slip threshold value.

An example method includes an operation to interpreting a motive torque value, a vehicle grade value, and a vehicle acceleration value; to determine a first correlation including a first correlation between the motive torque value and the vehicle grade value, to determine a second correlation between the motive torque value and the vehicle acceleration value, and to determine a third correlation between the vehicle grade value and the vehicle acceleration value, an operation to adapt an estimated vehicle mass value, an estimated vehicle drag value, and an estimated vehicle effective inertia value in response to the first correlation, the second correlation, and the third correlation, an operation to determine an adaptation consistency value, and in response to the adaptation consistency value, to adjust an adaptation rate of the adapting, and an operation to iteratively perform the preceding operations to provide an updated estimated vehicle mass value.

Certain further operations of the example method are described following, any one or more of which may be included in certain embodiments. An example method includes adapting by one of slowing or halting adapting of the estimated values in response to the first correlation, the second correlation, and the third correlation having an unexpected correlation configuration; adapting by increasing or continuing adapting the estimated values in response to the first correlation, the second correlation, and the third correlation having an expected correlation configuration; where the expected correlation configuration includes a positive correlation for the first correlation and the second correlation, and a negative correlation for the third correlation; where the expected correlation configuration further includes a linearity value corresponding to each of the first correlation, the second correlation, and the third correlation; where the adapting includes one of slowing or halting adapting the estimated values in response to the first correlation, the second correlation, and the third correlation having an unexpected correlation configuration; where the unexpected correlation includes a negative correlation for the first correlation and/or the second correlation, and/or a positive correlation for the third correlation. An example method includes adjusting the adaptation rate by increasing or holding an adjustment step size in the estimated vehicle mass value, the estimated vehicle effective inertia value, and/or the estimated vehicle drag value in response to the adaptation performing at least one operation such as: monotonically changing each estimated value, and/or and monotonically changing at least one estimated value and holding the other estimated value(s) at a same value; where adjusting the adaptation rate includes decreasing an adjustment step size in estimated vehicle mass value, the estimated vehicle effective inertia value, and/or the estimated vehicle drag value in response to the adaptation changing a direction of adaptation in at least one of the estimated values; and/or where the adjusting the adaptation rate is performed in response to the changing the direction being a change greater than a threshold change.

An example method includes an operation to determine that a shift rail position sensor corresponding to a shift actuator controlling a reverse gear is failed, to determine that a gear selection is active requiring operations of the shift actuator, and in response to the gear selection and the failed shift rail position sensor, performing in order: commanding the shift actuator to a neutral position, confirming the neutral position by commanding a second shift actuator to engage a second gear, wherein the second shift actuator is not capable of engaging the second gear unless the shift actuator is in the neutral position, and confirming the second shift actuator has engaged the second gear, and commanding the shift actuator into the gear position in response to the gear selection.

Certain further operations of the example method are described following, any one or more of which may be included in certain embodiments. An example method includes determining the shift rail position sensor is failed by determining the shift rail position sensor is failed out of range; where determining the shift rail position sensor is failed includes determining the shift rail position sensor is failed in range; and/or where determining the shift rail position sensor is failed in range includes, in order: commanding the shift actuator to the neutral position, commanding the shift actuator to an engaged position, determining if the shift actuator engaged position is detected, in response to the shift actuator engaged position not being detected, confirming the neutral position by: commanding the shift actuator to the neutral position, commanding a second shift actuator to engage a second gear, where the second shift actuator is not capable of engaging the second gear unless the shift actuator is in the neutral positon, and confirming the second shift actuator has engaged the second gear, and determining the shift rail position sensor is failed in range in response to the neutral position being confirmed, and determining a shift rail operated by the shift actuator is stuck in response to the neutral position not being confirmed.

An example system includes a transmission having a solenoid operated actuator, and a controller including: a solenoid temperature circuit that determines an operating temperature of the solenoid, a solenoid control circuit that operates the solenoid in response to the operating temperature of the solenoid, where the operating includes providing an electrical current to the solenoid, such that a target temperature of the solenoid is not exceeded.

Certain further aspects of the example system are described following, any one or more of which may be included in certain embodiments. An example system includes the solenoid temperature circuit further determining the operating temperature of the solenoid in response to an electrical current value of the solenoid and an electrical resistance value of the solenoid; the solenoid temperature circuit further determining the operating temperature of the solenoid in response to a thermal model of the solenoid; the solenoid operated actuator including a reduced nominal capability solenoid; the solenoid operated actuator including at least one actuator such as: a clutch actuator, a valve actuator, a shift rail actuator, and a friction brake actuator; and/or where the solenoid control circuit further operates the solenoid by modulating at least one parameter such as: a voltage provided to the solenoid, a cooldown time for the solenoid, and/or a duty cycle of the solenoid.

An example system includes a transmission having at a pneumatic clutch actuator, a clutch position sensor configured to provide a clutch actuator position value, and a controller including: a clutch control circuit that provides a clutch actuator command, where the pneumatic clutch actuator is responsive to the clutch actuator command, and a clutch actuator diagnostic circuit that determines that a clutch actuator leak is present in response to the clutch actuator command and the clutch actuator position value.

Certain further aspects of the example system are described following, any one or more of which may be included in certain embodiments. An example system includes the clutch actuator diagnostic circuit further determining the clutch actuator leak is present in response to the clutch actuator position value being below a threshold position value for a predetermined time period after the clutch actuator command is active; where the clutch actuator diagnostic circuit further determines the clutch actuator leak is present in response to the clutch actuator position value being below a clutch actuator position trajectory value, the clutch actuator position trajectory value including a number of clutch actuator position values corresponding to a plurality of time values; and the system further including a source pressure sensor configured to provide a source pressure value, and where the clutch actuator diagnostic circuit further determines the clutch actuator leak is present in response to the source pressure value.

An example system further includes a transmission having at least one gear mesh operatively coupled by a shift actuator, and a controller including a shift characterization circuit that determines that a transmission shift operation is experiencing a tooth butt event, the system further including a means for clearing the tooth butt event. Certain non-limiting examples of the means for clearing the tooth butt event are described following. An example means for clearing the tooth butt event includes the controller further including a shift control circuit, where the shift control circuit provides a reduced rail pressure in a shift rail during at least a portion of the tooth butt event, where the shift rail is in operationally coupled to the shift actuator. An example means for clearing the tooth butt event includes the controller including a clutch control circuit, where the clutch control circuit modulates an input shaft speed in response to the tooth butt event, and/or where the clutch control circuit further modulates the input shaft speed by commanding a clutch slip event in response to the tooth butt event. An example means for clearing the tooth butt event includes the controller including a friction brake control circuit, where the friction brake control circuit modulates a countershaft speed in response to the tooth butt event. An example means for clearing the tooth butt event includes a means for controlling a differential speed between shafts operationally coupled to the gear mesh to a selected differential speed range, where the selected differential speed range includes at least one speed range value such as: less than a 200 rpm difference; less than a 100 rpm difference; less than a 50 rpm difference; about a 50 rpm difference; between 10 rpm and 100 rpm difference; between 10 rpm and 200 rpm difference; and/or between 10 rpm and 50 rpm difference.

An example system includes a clutch that selectively decouples a prime mover from an input shaft of a transmission, a progressive actuator operationally coupled to the clutch, where a position of the progressive actuator corresponds to a position of the clutch, and a means for disengaging the clutch to provide a reduced driveline oscillation, improved driver comfort, and/or reduced part wear. Certain non-limiting examples of the means for disengaging the clutch are described following. An example means for disengaging the clutch includes a controller having a clutch control circuit that modulates a clutch command in response to at least one vehicle operating condition, and where the progressive actuator is responsive to the clutch command; where the at least one vehicle operating condition such as: a service brake position value, a service brake pressure value, a differential speed value between two shafts in a transmission including the clutch and progressive actuator, and/or an engine torque value; and/or where the clutch control circuit further modulates the clutch command to provide a selected clutch slip amount.

These and other systems, methods, objects, features, and advantages of the present disclosure will be apparent to those skilled in the art from the following detailed description of the preferred embodiment and the drawings.

All documents mentioned herein are hereby incorporated in their entirety by reference. References to items in the singular should be understood to include items in the plural, and vice versa, unless explicitly stated otherwise or clear from the text. Grammatical conjunctions are intended to express any and all disjunctive and conjunctive combinations of conjoined clauses, sentences, words, and the like, unless otherwise stated or clear from the context.

