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AssigneeChrysler Corporation
InventorsGerald L. Holbrook, Maurice B. Leising, David L. Kwapis
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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. When a tip-in condition is sensed, a more aggressive fast fill of the apply element is undertaken in order to handle an approaching input torque increase.
In an electronic controller for an electronically controlled vehicle automatic transmission system wherein the vehicle includes sensors for providing signals indicative of vehicle operating conditions, the transmission system includes a plurality of solenoid-actuated valves being movable and having logical operating states (ON and OFF) responsive to an electrical signal to control flow of a fluid to cause application or release of a friction element and wherein said electronic controller includes means for receiving input signals from said sensors indicative of predetermined vehicle conditions, memory means for storing information, processor means for performing calculations and generating output signals, and means for applying said output signals to said solenoid-actuated valves, a method of controlling a coastdown shift comprising the steps of:
In an electronic controller for an electronically controlled vehicle automatic transmission system wherein the vehicle includes sensors for providing signals indicative of vehicle operating conditions, the transmission system includes a plurality of solenoid-actuated valves responsive to an electrical signal to control flow of a fluid to cause application or release of a friction element and wherein said electronic controller includes means for receiving input signals from said sensors indicative of predetermined vehicle conditions, memory means for storing information, processor means for generating output signals and means for applying said output signals to said solenoid-actuated valves, a method of controlling a coastdown shift comprising the steps of:
In an electronic controller for an electronically controlled vehicle automatic transmission system wherein the vehicle includes sensors for providing signals indicative of vehicle operating conditions, the transmission system includes a plurality of solenoid-actuated valves responsive to an electrical signal to control flow of a fluid to cause application or release of a vehicle transmission friction element and wherein said electronic controller includes means for receiving input signals from said sensors indicative of predetermined vehicle conditions, memory means for storing information, processor means for generating output signals and means for applying said output signals to said solenoid-actuated valves, a method of controlling a coastdown shift comprising the steps of:
Dependencies are inferred from the claim text.