Abstract: A method of releasing a lockup clutch for a fluid coupling assembly disposed between an engine and an automatically shiftable transmission during a negative engine torque mode of operation is provided. The method includes the steps of: A) determining a current engine torque value prior to commanding the engine to ramp to a target engine torque value; B) commanding the engine to a target engine torque value wherein the target engine torque value is one of a zero and near zero value; C) holding the engine at the target engine torque value; and D) releasing or disengaging the lockup clutch when the engine is operating at the target engine torque value. A powertrain is also provided having a controller sufficiently configured to operate according to the method of the present invention.

Abstract: The method of the present invention is adapted to control transmission oil temperature. According to a preferred embodiment, the engine coolant temperature may be controlled in addition to or regardless of transmission oil temperature. To maintain transmission and/or engine temperature, the present invention is preferably configured to limit the engine's power when required to ensure the powertrain (engine and transmission) does not overheat.

Abstract: A driver-initiated low traction control method limits the drive torque of a motor vehicle during operation on low traction road surfaces. The low traction control mode is initiated by actuation of a switch or by moving a transmission range selector to a Low range while the vehicle is substantially stopped, and terminated by further actuation of the switch or by returning the range selector back to the Drive setting. The low traction control mode limits the engine torque as required to limit the drive wheel torque and its rate of change, so long as cruise control is inactive, the accelerator pedal setting is less than a reference level, and the transmission is operating in a gear other than its top gear. When the low traction control mode is terminated, the engine torque limits are progressively removed in a way that does not produce perceptible acceleration or deceleration of the vehicle.

Abstract: A driver-initiated low traction control method limits the drive torque of a motor vehicle during operation on low traction road surfaces. The low traction control mode is initiated by actuation of a switch or by moving a transmission range selector to a Low range while the vehicle is substantially stopped, and terminated by further actuation of the switch or by returning the range selector back to the Drive setting. The low traction control mode limits the engine torque as required to limit the drive wheel torque and its rate of change, so long as cruise control is inactive, the accelerator pedal setting is less than a reference level, and the transmission is operating in a gear other than its top gear. When the low traction control mode is terminated, the engine torque limits are progressively removed in a way that does not produce perceptible acceleration or deceleration of the vehicle.

Abstract: An engine control for a motor vehicle powertrain coordinates engine speed and torque limiting during automatic transmission range changing so as to provide both vehicle rocking capability and adequate protection for the transmission. A transmission controller temporarily limits the engine speed to a predetermined value on each transition to or from the forward or reverse ranges, and superimposes continuous engine speed and torque limitations when an abusive rocking maneuver is detected. An abusive rocking maneuver is detected when the driver commands at least a specified number of successive range shifts during a predetermined time interval, and the speed and torque limitations are imposed until range shifting is discontinued for at least a calibrated period of time.

Abstract: An engine control for a motor vehicle powertrain coordinates engine speed and torque limiting during automatic transmission range changing so as to provide both vehicle rocking capability and adequate protection for the transmission. A transmission controller temporarily limits the engine speed to a predetermined value on each transition to or from the forward or reverse ranges, and superimposes continuous engine speed and torque limitations when an abusive rocking maneuver is detected. An abusive rocking maneuver is detected when the driver commands at least a specified number of successive range shifts during a predetermined time interval, and the speed and torque limitations are imposed until range shifting is discontinued for at least a calibrated period of time.

Abstract: A powertrain having a controller for limiting the torque and power inputs to a transmission as determined by operating parameters and design features of the transmission. These parameters and design features include torque limits for various components in the transmission, torque ratio of the torque converter, the design K factor of the torque converter, gear ratios of the transmission, operating condition of the torque converter clutch, and input power limits for the transmission. A programmable digital computer includes a subroutine that evaluates and establishes torque limits and input speed limits from the design features and operating parameter. The controller sets the limits for each transmission ratio including reverse such that a family of transmission can be coupled to a single engine design without overpowering the transmission should the engine be capable of greater output power than the transmission can accept.

Abstract: A powertrain having a controller for limiting the torque and power inputs to a transmission as determined by operating parameters and design features of the transmission. These parameters and design features include torque limits for various components in the transmission, torque ratio of the torque converter, the design K factor of the torque converter, gear ratios of the transmission, operating condition of the torque converter clutch, and input power limits for the transmission. A programmable digital computer includes a subroutine that evaluates and establishes torque limits and input speed limits from the design features and operating parameter. The controller sets the limits for each transmission ratio including reverse such that a family of transmission can be coupled to a single engine design without overpowering the transmission should the engine be capable of greater output power than the transmission can accept.

Abstract: An improved automatic shift transmission control method establishes an initial methodology for sharing adaptive corrections among shift parameters stored for related types of shifts, and subsequently modifies the initial methodology as the adapted parameters converge on respective optimum values. Individual shift types are initially categorized to indicate the degree of cross-adaptive correction, and when shift parameter convergence occurs, the shift types are re-categorized, thereby modifying the initial cross-adaptive methodology to restrict further cross-adaptive correction. A given shift type is automatically reset to an initial or prior categorization to permit less restricted cross-adaptive correction if reset conditions are met. In this way, the methodology for sharing adaptive corrections automatically evolves to suit individual transmission operating characteristics and conditions, and effectively prevents degradation of a shift due to sharing of adaptive corrections developed for a related shift.

Abstract: A system is disclosed for determining an effective throttle value of an internal combustion engine for controlling automatic transmission shift points. In one embodiment, the system is operable to determine an effective throttle value as a function of commanded fueling and engine speed under operating conditions wherein engine torque is requested by a system/component other than manual throttle control to thereby provide a throttle value indicative of what throttle position or percentage would be under present operating conditions if engine torque was being requested via manual throttle control. The present invention accordingly overcomes deficiencies in known automatic transmission shift point control systems by continuously computing an equivalent throttle percentage whenever fueling or requested torque values are not dominated by actual throttle (e.g. accelerator pedal) percentage.

Abstract: A road speed control system for a vehicle driven by an internal combustion engine includes a control computer operable to control engine fueling based on inputs from at least an accelerator pedal position sensor, a vehicle speed signal, and at least one control signal. According to one aspect of the invention, the control computer is responsive to a first control signal to decrease the maximum road speed limit value and to a second control signal to increase the maximum road speed value, to thereby provide a road speed limiting system operable under manual engine fueling conditions. According to another aspect of the invention, the control computer is responsive to at least one control signal to activate a maximum road speed limit override feature for temporarily increasing the maximum road speed limit value to, for example, facilitate passing attempts.

Abstract: A road speed control system for a vehicle driven by an internal combustion engine includes a control computer operable to control engine fueling based on inputs from at least an accelerator pedal position sensor, a vehicle speed signal, and at least one control signal. According to one aspect of the invention, the control computer is responsive to a first control signal to decrease the maximum road speed limit value and to a second control signal to increase the maximum road speed value, to thereby provide a road speed limiting system operable under manual engine fueling conditions. According to another aspect of the invention, the control computer is responsive to at least one control signal to activate a maximum road speed limit override feature for temporarily increasing the maximum road speed limit value to, for example, facilitate passing attempts.

Abstract: A vehicle/engine acceleration rate management system includes means for determining vehicle acceleration rate and a control computer providing a fueling signal to an internal combustion engine fueling system. The control computer is responsive to a gear ratio signal indicative of one of a plurality of selectable transmission gear ratios currently engaged with the engine and a vehicle acceleration rate signal to control the vehicle acceleration rate by limiting the fueling signal whenever the vehicle acceleration rate signal exceeds a vehicle acceleration limit function. In one embodiment, such vehicle acceleration rate limiting is performed only for vehicle speeds above a threshold vehicle speed, and an identical engine acceleration rate limiting procedure is performed at vehicle speeds below the threshold vehicle speed. In either case, such acceleration rate limiting is preferably only performed under manual control of engine fueling via an accelerator pedal or the like.

Abstract: An electronic throttle pedal nonlinear filter. During throttle control of a vehicle's all speed governor, a nonlinear prefilter is used to modify the reference command. This prefilter can be used to heavily filter small throttle corrections, while allowing large throttle changes to have little or no filtering. By heavily filtering small throttle corrections, throttle sensitivity can be reduced, helping the throttle "feel" when driving over bumpy roads or when making small throttle changes. Little filtering when making large throttle changes helps to give a fast governor response when a large acceleration or deceleration is desired. The filter works by comparing the past value of the all speed governor reference speed (or throttle position) to a rate limited value of the current reference speed (or throttle position). This difference is used to look up a filter coefficient in a table. This coefficient is used in a conventional first-order digital lag filter to produce the filter output.