Abstract: A method/system for controlling downshifting in an automated mechanical transmission system (10) utilized on a vehicle. When a downshift from a currently engaged ratio (GR) is required (ES<ES.sub.D/S), skip downshifts (GR.sub.TARGET =GR-N, N>1) and then single downshifts (GR.sub.TARGET =GR-1) are evaluated in sequence.

Abstract: A control system/method for controlling engine (12) flywheel (T.sub.FW) torque in a vehicular powertrain system (10) including an electronically controlled engine and a torque load limited drivetrain system (11) is provided. The control will sense values of a control parameter (GR, OS) indicative of potential overloading of the drivetrain at maximum engine flywheel torque and will cause engine flywheel torque to be limited to a value less than the maximum value thereof. Flywheel torque is determined as a function of torque values available on the vehicle electronic data link (DL).

Abstract: A control for enhanced manual shifting in a computer-assisted (48) vehicular splitter-type compound transmission (16) having a nonsynchronized, enlarged backlash main section (16A) shifted by a manually operated shift lever (31) and a controller (42). The splitter section (16E) is provided with a three-position (L, H, N) actuator (46) and is commanded to a splitter-neutral position upon sensing a main section shift to neutral to reduce the inertia of the main shaft assembly and reduce the need to synchronize the main section.

Abstract: A control for providing a smooth, high quality torque converter lockup event in an automated mechanical transmission system (10) including a fuel-controlled engine (12) and a mechanical transmission (14) drivingly coupled by a torque converter and torque converter lockup clutch assembly (16). To achieve smooth torque converter lockup, engine torque is smoothly ramped down to a relatively low value and maintained at that value until the torque converter lockup clutch is effectively engaged.

Abstract: A semi-automatic shift implementation system (100) for a lever-shifted mechanical transmission (10) includes an intent-to-shift sensor (122), such as an intent-to-shift button (120). Upon sensing an intent to shift, a controller (146) will cause the engine to be fueled to minimize torque-lock conditions at jaw clutches to be disengaged.

Abstract: A control system for controlling jaw clutch (88) engagement for completing upshifts. The synchronous window ((OS*GR.sub.T).+-.offset) for commanding jaw clutch engagement is increased upon sensing relative great vehicle deceleration (dOS/dt<REF.sub.1) or relatively great vehicle acceleration and relative small engine deceleration (dOS/dt<REF.sub.1) and (dES/dt>REF.sub.2).

Abstract: A partially automated transmission system (100) and method for controlling same is provided. The system includes a manually shifted splitter-type transmission (10) having a spatter section (14) and a manually shifted main section (12). The splitter section is controlled by a splitter actuator (116) under control from a system ECU (146). The operator is provided with a selector (120) for selecting upshifts and downshifts. Preferably, shifting in the upper group of ratios (A (9/10)) is fully automatic.

Abstract: A semi-automatic shift implementation system (100) for a manually shifted, output-splitter-type compound transmission (10) having gear ratios selectively engaged and disengaged by jaw clutches (48, 50) selectively positioned by a shift lever (57). The system will sense a main transmission section (12) neutral condition, a master clutch disengaged condition, and a target gear ratio (GR.sub.T) and will automatically cause the splitter clutch (80) to disengage until the main section is reengaged and the system engine (102) to achieve or dither about a substantially synchronous speed for engaging the target ratio.

Abstract: A system and method for decreasing the time required to complete a ratio change in an electronically enhanced powertrain system is provided. The powertrain system includes a number of devices for providing a retarding torque to engine rotation to increase the decay rate of the engine speed during an upshift. These devices include an engine brake and an input shaft brake. A retarding torque is also provided by increasing engine accessory load by controlling various engine accessories such as a cooling fan, an air compressor, a hydraulic pump, an air conditioning compressor, and an alternator.

Abstract: A semi-automatic shift implementation system (100) for a manually lever (57) shifted, splitter-type transmission (10). Lever shifts are semi-automatically implemented by automatic splitter shifting and, upon sensing transmission neutral, automatic control of engine fueling to cause substantially synchronous conditions for engagement of a target ratio.

Abstract: A semi-automatic shift implementation system (100) for a manually shifted transmission (10) having gear ratios selectively engaged and disengaged by means of jaw clutches (48, 50) selectively positioned by a shift lever (57). The system will sense a transmission neutral condition and a target gear ratio (GR.sub.T) and will automatically cause the system engine (102) to achieve a synchronous speed for engaging the target ratio.

Abstract: Control logic for an automated mechanical transmission system (100) allows signals indicative of input shaft (IS) and output shaft (OS) rotational speed to be utilized to determine engagement of a target gear ratio (GR.sub.T) without false readings caused by engine synchronizing.

Abstract: A pressurized fluid-operated, three-position shift actuator piston assembly (12) and associated control system (10) are provided. The system requires only a single controlled source of pressurized fluid (A) to provide movement to and retention in a selected one of three axially displaced positions (D, N, OD).

Abstract: A system and method for decreasing the time required to complete a ratio change in an electronically enhanced powertrain system is provided. The powertrain system includes a number of devices for providing a retarding torque to engine rotation to increase the decay rate of the engine speed during an upshift. These devices include an engine brake and an input shaft brake. A retarding torque is also provided by increasing engine accessory load by controlling various engine accessories such as a cooling fan, an air compressor, a hydraulic pump, an air conditioning compressor, and an alternator.

Abstract: A splitter-type compound transmission (110) is provided with a splitter clutch (180) having increased backlash and a three-position actuator (202) controlled by a microprocessor-based controller (222). The controller will receive inputs for various sensors including a sensor indicating the position of a manual splitter selector switch (218).

Abstract: A method/system for controlling an automated transmission is provided wherein upon assembly of a vehicle, the intercept (A) and slope (B) values defining the presumed linear relationship between engine deceleration rate and engine accessory torque (dES/dt rate=A+(B * T.sub.ACCES)) and/or the value of engine rotational moment-of-inertia (I) for that particular vehicle are determined and memorized. Thereafter, the transmission is controlled as a function of these determined values.

Abstract: An adaptive control system/method for an at least partially automated vehicular mechanical transmission system (10) is provided for determining the value of a control parameter (T.sub.ACCES) indicative of accessory torque when the vehicle is in motion and the value of a control parameter (dES/dt rate) indicative of engine deceleration rate when the vehicle is not in motion. A relationship (dES/dt rate=A+B * T.sub.ACCES) between engine deceleration rate and accessory torque is determined and allows derivation of one parameter from the other parameter during vehicle operating conditions wherein the other parameter may be directly determined from sensed inputs (T.sub.EG, T.sub.BEF, ES).

Abstract: An inertia brake is coupled to a rotating shaft of a vehicle transmission where a ball ramp actuator energized by an electrical coil is used to load a clutch pack which frictionally creates a braking torque on the rotating shaft to facilitate synchronous gear engagement. A control system includes an electronic control unit and an inertia brake controller where a variety of sensors provide signals to the electronic control unit uses the sensor signals to generate a deceleration signal to the inertia brake controller which in turn generates and supplies the appropriate level of electrical current to the electrical coil which is used to energize the ball ramp actuator thereby accurately controlling the rate of shaft rotational deceleration.

Abstract: A transmission shifting system for a gear change transmission where an actuator responding to a control signal is used to axially displace a secondary shift rail thereby preloading a spring acting upon a primary shift rail where a coupling element permits relative motion between the secondary shift rail and the primary shift rail until gear synchronization or a torque break occurs allowing the desired gear shift to occur. The relative motion which results in a spring preload force to be generated on the primary shift rail continues until the secondary shift rail contacts the portion of the coupler adjacent to a primary flange formed as part of the primary shift rail whereupon the actuator is solidly linked to the shift rail and a shift fork.

Abstract: A robust engine fueling control is provided for assuring neutral attainment in a vehicular automated mechanical transmission system (10) having a manually controlled master clutch (16). Upon sensing a requirement for a shift into transmission neutral, the disengaging jaw clutch members (134A/142A) are constantly urged into a disengaged position, fuel is caused to decrease to idle (302), and then fuel is blipped by increasingly larger amounts (304, 306, 308) until neutral is sensed.