Abstract: An automatic transmission for a vehicle includes an input shaft, an output shaft, a first and second plurality of gears, and a series of engagement elements. The series of engagement elements includes at least one overrunning engagement element in mechanical communication with the second plurality of gears. A controller is operable to disengage a first engagement element associated with a first one of the first plurality of gears and apply a second engagement element associated with a second one of the first plurality of gears to achieve a speed change of the first plurality of gears. The controller is adapted to disengage one of the overrunning engagement elements from engagement with one of the second plurality of gears within a range of 20 to 120 milliseconds after the speed change of the first plurality of gears to accomplish a gear shift of the transmission.

Abstract: A method of double-downshifting from a first gear ratio to a second gear ratio includes the steps of first reducing torque transfer from a first clutch to a first driven gear. Engine speed then increases. Next, torque transfer from a second clutch to a third driven gear is increased while simultaneously the first clutch is disengaged from the first driven gear. Torque transfer from the second clutch to the third driven gear is then reduced. Torque transfer from the second clutch to the third driven gear is next increased. The first clutch is engaged to the second driven gear. Then, torque transfer from the first clutch to the second driven gear is increased while simultaneously the torque transfer from the second clutch to the third driven gear is reduced. Finally, the second clutch is disengaged from the third driven gear.

Abstract: A method of double-downshifting from a first gear ratio to a second gear ratio includes the steps of first reducing torque transfer from a first clutch to a first driven gear. Engine speed then increases. Next, torque transfer from a second clutch to a third driven gear is increased while simultaneously the first clutch is disengaged from the first driven gear. Torque transfer from the second clutch to the third driven gear is then reduced. Torque transfer from the second clutch to the third driven gear is next increased. The first clutch is engaged to the second driven gear. Then, torque transfer from the first clutch to the second driven gear is increased while simultaneously the torque transfer from the second clutch to the third driven gear is reduced. Finally, the second clutch is disengaged from the third driven gear.

Abstract: A method and arrangement for controlling a continuously variable transmission with improved response time, the continuously variable transmission having a first pulley engagable with an engine and having a second pulley drivingly connected to the first pulley by a belt. The first and second pulleys each have a fixed sheave and a movable sheave, a position of the movable sheaves defining a transmission ratio. The method and arrangement provides for disengaging the engine from the first pulley and increasing the speed of the engine to a target speed, reducing pressure to the movable sheave of the first pulley to a low value, increasing pressure to the movable sheave of the second pulley causing it to rapidly move to a new position thereby changing the transmission ratio to a target transmission ratio, increasing the pressure to the first pulley, and reengaging the engine to the first pulley.

Abstract: A method and arrangement for controlling a continuously variable transmission with improved response time, the continuously variable transmission having a first pulley engagable with an engine and having a second pulley drivingly connected to the first pulley by a belt. The first and second pulleys each have a fixed sheave and a movable sheave, a position of the movable sheaves defining a transmission ratio. The method and arrangement provides for disengaging the engine from the first pulley and increasing the speed of the engine to a target speed, reducing pressure to the movable sheave of the first pulley to a low value, increasing pressure to the movable sheave of the second pulley causing it to rapidly move to a new position thereby changing the transmission ratio to a target transmission ratio, increasing the pressure to the first pulley, and reengaging the engine to the first pulley.

Abstract: An interactive engine and automatic transmission control system is provided wherein spark and air control are used to control engine speed to maintain a small positive torque on the transmission before and after coast down shifts. More particularly, a transmission controller is electrically coupled to an engine controller in a motor vehicle such that information can be passed therebetween. Such information includes a start of shift signal, a phase of the shift signal (i.e., clutch release phase, speed change phase, or clutch application phase), and a shift complete signal. In addition, the transmission controller identifies the type of shift that is occurring (i.e., fourth gear to third, third to second, or second to first), transmission oil temperature and the acceleration (braking) rate of the vehicle to the engine controller.

Abstract: A method and apparatus are provided for controlling the hydraulic line pressure in an automatic transmission for a vehicle in response to the measured pressure and torque transmitted through the transmission such that a minimum hydraulic line pressure is provided to the frictional elements to achieve a non-slip condition through the transmission which increases transmission efficiency and fuel economy. Hydraulic line pressure is controlled by activating a solenoid activated valve. Control signals are based on measured hydraulic line pressure, engine speed, turbine speed, vehicle speed, driver selected gear, and torque converter operating condition for the solenoid actuated valve. The present invention further provides a closed-loop adaptive control technology to learn the minimum line pressure to compensate for variability in the clutch return springs, friction characteristics, surface finishes, as well as hydraulic wear, and changes over the life of the transmission.

Abstract: A torque management apparatus for an automatic transmission of an internal combustion engine. The apparatus includes a sensor for sensing shifting of the transmission to a Neutral mode. An engine limiting means is operatively connected to a sensor for limiting the speed of the engine in response to the sensor, which senses the shifting of the transmission into or from the Neutral mode. Also, an engine delimiting means is operatively connected to the sensor and to the engine limiting means for returning the engine to a normal throttle speed in response to shifting of the transmission out of the Neutral mode. The engine limiting means and the engine delimiting means minimize stress on the transmission due to the engagement and disengagement of the transmission components caused by the shifting of the transmission in and out of a Neutral mode.

Abstract: An interactive cruise control system and method for providing automatic speed control of a vehicle with improved shifting of an automatic transmission. The system and method controls speed of a vehicle equipped with cruise control and minimizes downshifts in an automatic transmission of the vehicle. Vehicle speed is detected and compared with a setpoint speed which is associated with the cruise control system. Transmission gear shifting is determined based on predetermined shift schedule points. Determined transmission gear downshifts are prevented for a kickdown delay period based on vehicle speed loss and the presence of vehicle deceleration. Also provided is an overspeed reduction method for causing a transmission downshift during an overspeed condition with the throttle closed. Further, the system provides hunting prevention between both second gear and third gear as well as between third gear and fourth gear for a four speed automatic transmission.

Abstract: An interactive cruise control system and method for providing automatic speed control of a vehicle with improved shifting of an automatic transmission. The system and method controls speed of a vehicle equipped with cruise control and minimizes downshifts in an automatic transmission of the vehicle. Vehicle speed is detected and compared with a setpoint speed which is associated with the cruise control system. Transmission gear shifting is determined based on predetermined shift schedule points. Determined transmission gear downshifts are prevented for a kickdown delay period based on vehicle speed loss and the presence of vehicle deceleration. Also provided is an overspeed reduction method for causing a transmission downshift during an overspeed condition with the throttle closed. Further, the system provides hunting prevention between both second gear and third gear as well as between third gear and fourth gear of a four speed automatic transmission.

Abstract: An interactive cruise control system and method for providing automatic speed control of a vehicle with improved shifting of an automatic transmission. The system and method controls speed of a vehicle equipped with cruise control and minimizes downshifts in an automatic transmission of the vehicle. Vehicle speed is detected and compared with a setpoint speed which is associated with the cruise control system. Transmission gear shifting is determined based on predetermined shift schedule points. Determined transmission gear downshifts are prevented for a kickdown delay period based on vehicle speed loss and the presence of vehicle deceleration. Also provided is an overspeed reduction method for causing a transmission downshift during an overspeed condition with the throttle closed. Further, the system provides hunting prevention between both second gear and third gear as well as between third gear and fourth gear of a four speed automatic transmission.

Abstract: A method of determining the deterioration of automatic transmission fluid by detecting shudder during the EMCC portion of air conditioner clutch engagement. Shudder is detected by calculating the acceleration of the turbine during EMCC slip with the following equation:.SIGMA..alpha..sub.t =.SIGMA..alpha..sub.t (i-1)+.alpha..sub.twhere .alpha..sub.t represents the absolute value of turbine acceleration. In a preferred embodiment, the turbine acceleration is summed for twenty-eight periods of 7 msec each after the start of EMCC and the determination that shudder occurred made if the resulting value exceeds a predetermined number. In a further preferred embodiment, the method is used to modify the air conditioner compressor clutch engagement sequence. Once it is determined that shudder is occurring during the EMCC portion of the air conditioner compressor clutch engagement sequence, the EMCC portion of the air conditioner clutch engagement sequence is eliminated or bypassed.

Abstract: An electronic transmission coastdown shift control method in which the transmission controller has the capacity to predict timing of apply element application. The control method of the present invention improves the shift sequence by accurately prefilling the apply element. The transmission controller vents the release element when apply element application is imminent and controls the application of the oncoming element to achieve a controlled element exchange for a smooth coastdown shift. A duty cycle is then applied to complete the oncoming element application with a soft yet quick application and control the engagement of the oncoming element. The identification of the application point of the oncoming element enables the apply element fill volume to be learned during coastdown shifts. It also enables the calculation of a line pressure correction factor necessary in accurately predicting application of the apply element. Anticipation of a coastdown tip-in condition is also provided.

Abstract: The present invention provides a method of adaptively modifying the transmission shift schedule during various driving conditions. The method determines a desirable upshift schedule based upon driving conditions, and adaptively adjusts the transmission shift schedule in accordance with a predefined criteria. This is accomplished by observing vehicle speed and other transmission operating parameters and determining whether an adaptive shift schedule adjustment is required. If the shift schedule is adaptively adjusted, the driving parameters are further monitored to determine at which time the shift schedule may be reset to its initial state.

Abstract: A method of determining the driver selected operating mode of an automatic transmission system wherein a controller is programmed to determine the driver selected operating mode of the transmission with a binary code transmitted from sensors sensing the position of a manually actuated shift lever.

Abstract: A method of adaptively scheduling an upshift. The method determines whether the vehicle can maintain speed in a high gear and, if it cannot, to inhibit the lower to higher gear upshift. This is accomplished by observing vehicle acceleration in the lower gear, determining whether the vehicle will be capable of providing a predetermined value of acceleration after an upshift of the gear assembly to a higher gear. If the vehicle will not be capable of providing the predetermined value of acceleration, then the upshift will be prevented.

Abstract: A method is provided which controls the release element during a coastdown shift to prevent the release element from venting whenever slip is detected to ensure enough fluid volume to apply the release element if needed for an electronic automatic transmission system.

Abstract: A method of controlling the hold-speed during an upshift of an automatic transmission for a vehicle. The method controls the level of slip through the reapplication of the release element in response to predetermined conditions which include a determination of whether the second derivative of slip has exceeded a particular limit.

Abstract: An adaptive control system in an automatic four-speed transmission having a unique clutch and gear arrangement which eliminates the need for additional gearing and one over-running clutch, while requiring only one more friction element. The vehicle transmission assembly includes a transmission housing, a rotatable input member, an output member, and a gear assembly for changing the ratio of torque between the input member and the output member. Three clutch assemblies selectively couple the rotatable input member to predetermine gears of the gear assembly and two brake assemblies selectively couple predetermined gears of the gear assembly to the transmission housing. The gear assembly includes the first planetary gear set and a second planetary gear set.

Abstract: The present invention is a hydraulic system for an automatic transmission having a torque converter for receiving power from a prime mover, and an assembly of hydraulically operated friction elements which provide clutch and brake functions. The hydraulic system includes a pump, a regulator valve, and a torque converter control valve for regulating fluid pressure to the torque converter. The hydraulic system also includes a manual valve and a plurality of solenoid valves for controlling fluid flow received at least in part from the manual valve to each of the friction elements. The hydraulic system further includes a switch valve operatively associated with the solenoid valve for enabling two of the friction elements to be controlled from only one of the solenoid valves.