Abstract: A method for synchronizing a plurality of pedal position sensors in a motor vehicle. A series of voltages are accumulated from each of a plurality of pedal position sensors. Representative voltages are determined from the series of voltages. The representative voltages are assigned to linear relationships from which an offset is determined.

Abstract: A method for synchronizing a plurality of pedal position sensors in a motor vehicle. A series of voltages are accumulated from each of a plurality of pedal position sensors. Representative voltages are determined from the series of voltages. The representative voltages are assigned to linear relationships from which an offset is determined.

Abstract: A method of determining the shift lever position of an electronic automatic transmission system by identifying the mode of transmission operation selected by the driver of the vehicle to provide hysteresis between the park, reverse, neutral, drive and low positions, to permit improved performance and response of the controller and to permit limited operation of the controller upon the occurrence or detection of a fault effecting the performance of the transmission. Such faults include the loss of a PRND2L sensor and the loss of one or more sensors indicative of the dynamics of the vehicle or hydraulic circuit.

Abstract: A manual valve arrangement is provided for an automatic transmission which provides for uninterrupted friction element control even though manual valve porting is being switched. An extra multi-select solenoid combined with porting through the manual valve and dual acting ball check assemblies permits selected friction elements to be controlled from two solenoids simultaneously. The extra multi-select solenoid, which is a normally-open solenoid valve, permits an energy savings logic mode in which the a normally-closed solenoid valve can be de-energized. Output from the extra multi-select solenoid is switched to different clutch elements when the manual valve is moved from the reverse position to the drive position and from the drive position to the second position.

Abstract: The present invention provides a method for shifting from a first gear state to a second gear state which holds one element at a predetermined level until the second reaches its fill volume. In this method, one element is applied while the other element is released. The element which reaches its fill volume first is held at a control limit. This control limit is defined by a volume between the first clutch element and a predetermined point above the fill volume of the first clutch element. This clutch element is then maintained at within the control limit until the other clutch element reaches its fill volume. The maintained clutch element is then released shortly after the other clutch element has reached its fill volume. This method ensures that neither fighting or slipping occurs between the two elements.

Abstract: The present invention provides a method for shifting from a first gear state to a second gear state which holds one element at a predetermined level until the second reaches its fill volume. In this method, one element is applied while the other element is released. The element which reaches its fill volume first is held at a control limit. This control limit is defined by a volume between the first clutch element and a predetermined point above the fill volume of the first clutch element. This clutch element is then maintained at within the control limit until the other clutch element reaches its fill volume. The maintained clutch element is then released shortly after the other clutch element has reached its fill volume. This method ensures that neither fighting or slipping occurs between the two elements.

Abstract: An automatic transmission is provided with failsafe operation via a unique manual valve and multi-select solenoid arrangement. The transmission also provides for an energy saving logic operation mode.

Abstract: The present provides a shutdown shift schedule which allows a vehicle driver an increased number of gear states to increase driveability. This method monitors the gear state conditions indicative of the gear state which said automatic transmission is in. When the shift state conditions vary from predetermined standards, the controller uses the shutdown shift schedule in place of the shift schedule for changing gears of the automatic transmission. This shutdown shift schedule is adapted to allow a 3-1 shift when the shift solenoid is in a shift D position and the shift state is 3. The shutdown shift schedule is also adapted to allow a 3-2 shift when the shift state is 3 and the shift solenoid is in the shift 2 position.

Abstract: The present invention provides a means to learn and accommodate the amount of air that needs to be purged from a clutch circuit after being off for a predetermined time. The scheme helps to maintain proper control timing as necessary for good shift quality and clutch durability and further helps to minimize unnecessary delays in clutch application. Once the air has been purged, then normal control timing can be resumed.

Abstract: A novel transmission is provided that has a first, second, third and fourth gear, wherein said second gear includes two alternate and selectable speed ratios. The primary speed ratio of the second gear is used during upshifts and downshifts of adjacent gears. The alternate speed ratio of the second gear is utilized exclusively during downshifts from non-adjacent gears and may also be utilized during a downshift from the third gear depending on certain conditions and parameters. The primary speed ratio is larger than the alternate speed ratio of the second gear to provide better acceleration characteristics of the transmission during upshifting. The smaller alternate speed ratio of the second gear can provide smoother downshifts because of the less abrupt speed ratio change from the higher gears. Also, a method for controlling the gear selection of an automatic transmission having a plurality of gears is provided, wherein one position includes two speed ratios.

Abstract: A sensing system for detecting the position of a manually operated shift lever in an automatic transmission. The sensing system includes a plate member movable in response to movement of a shift lever. The plate member includes a generally flat contact surface having a predetermined pattern of electrically conductive and non-conductive areas. An electrical sensor unit is mounted in the transmission and positioned to communicate with the contact surface of the plate member. At least five electrical contact members engage the conductive and non-conductive areas on the contact surface generate binary codes having combinations that are indicative of the shift lever position in each of the predetermined operating modes. The engagement between the contact members and the contact surface further generates at least four unique binary codes indicative of the transitions between the predetermined operating modes.

Abstract: The present invention provides a method for determining fill volumes of a plurality of clutch elements in an automatic transmission wherein each clutch element is applied in a predefined order and the fill volume of each clutch element is obtained by determining when the rotational speed of the engine varies from the rotational speed of the transmission's turbine by a predefined amount. The plurality of clutch elements comprises at least a 2C, 4C, UD, OD, and LR clutch element.

Abstract: An automatic transmission control system is provided with extreme cold logic wherein when the transmission oil temperature is below a predetermined temperature so as to cause the transmission oil to have extremely viscus characteristics, the transmission prevents faulty shifting by limiting shifts between first and third gears. The first gear is obtained by application of a single hydraulically controlled clutch element in combination with a freewheel clutch element while the third gear operation can be obtained by engagement of a second clutch element in combination with the first clutch element. Since the shift between first and third gears only requires the application of the second clutch element in combination with the already engaged first clutch element, there is no risk of torque overlap between elements.

Abstract: A method for reinitializing vehicle parameters stored in a memory of a controller in a motor vehicle after a power loss to the controller includes the steps of determining whether predetermined conditions are right for transferring at least one vehicle parameter stored in a volatile memory of a controller, transferring the vehicle parameter stored in the volatile memory to a non-volatile memory if the predetermined conditions are right for transferring the vehicle parameter, determining whether predetermined conditions are right for re-initializing the vehicle parameter after a power loss to the controller, transferring the vehicle parameter from the non-volatile memory to the volatile memory if the predetermined conditions are right for re-initializing the vehicle parameter, and initializing the vehicle parameter with a predetermined initial value stored in the non-volatile memory to the volatile memory if the predetermined conditions are not right for re-initializing the vehicle parameter.

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 improved initial shift quality in an electronically controlled automatic transmission by enabling the friction element fill volumes to be "learned" by the transmission controller before the vehicle leaves the assembly line. An end of line (EOL) volume learn procedure is intended for final check out at car assembly or for other appropriate circumstances such as for service after a transaxle has been rebuilt or replaced, or as a diagnostic tool to help confirm an indicated condition of an element.Upon satisfaction of a set of initial conditions, an end of line volume learn procedure is initiated wherein the transmission is cycled through a number of phases, each phase generally corresponding to the application of a different friction element.

Abstract: The present invention provides an apparatus for indicating transmission operating mode based upon actual operating mode as determined by the transmission controller. The apparatus receives input signals from the PRNODDL switch of the electronically controlled automatic transmission in addition to pressure switch and speed data to determine and confirm transmission operating mode. The signals are processed by the automatic transmission controller and communicated to the instrument cluster for displaying transmission operating mode.

Abstract: A sensing system is provided for sensing the position of a manual gear select lever in an automatic transmission. The sensing system includes a plate member movable in response to movement of a shift lever and has a contact surface having a predetermined pattern of electrically conductive and non-conductive areas. An electrical sensing unit is mounted in the transmission so as to communicate with the contact surface of the plate member. A plurality of electrical contacts extend from the sensing unit to contact the conductive and non-conductive areas on the contact surface and generate binary codes in accordance with the position of the shift lever. Combinations of binary codes are provided for the operating modes and require at least two bit changes therebetween. In addition, transition codes are provided between each of the operating modes. The binary codes are provided to a transmission controller which determines the predetermined operating mode and transition modes therebetween.

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: 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.