Method and system for determining fill time for friction elements of automatic transmission
First Claim
1. A method for determining, using a piston stroke ratio of a piston, a fill time for a friction element in an automatic transmission that is either engaged or disengaged during shifting between an N-range, a D-range, and an R-range, the friction element being actuated by the piston, the method comprising:
- neutral compensating for the piston stroke ratio of said piston;
drive compensating for the piston stroke ratio of said piston; and
calculating a fill time using the compensated piston stroke ratio.
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Accused Products
Abstract
In order to more precisely calculate a fill time of a friction element of an automatic transmission that is either engaged or disengaged during shifting between an N-range, a D-range, and an R-range, this invention compensates a piston stroke ratio by detecting an N-range hold time and by using the N-range hold time and a pre-installed map when a shift signal indicating shifting into one of the D-and R-ranges from an N-range is detected, compensates the piston stroke ratio by detecting a D/R-range hold time and by using the D/R-range hold time and the pre-installed map when a shift signal indicating shifting into the N-range from one of the D- and R-ranges is detected, and calculates a fill time using the compensated piston stroke ratio.
4 Citations
20 Claims
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1. A method for determining, using a piston stroke ratio of a piston, a fill time for a friction element in an automatic transmission that is either engaged or disengaged during shifting between an N-range, a D-range, and an R-range, the friction element being actuated by the piston, the method comprising:
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neutral compensating for the piston stroke ratio of said piston;
drive compensating for the piston stroke ratio of said piston; and
calculating a fill time using the compensated piston stroke ratio. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A system for determining a fill time of friction elements of an automatic transmission comprising:
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a shift lever detector for detecting a position of a shift lever, which is operated by a driver, and outputting a corresponding shift lever change signal;
a timing device for measuring time intervals between a change in position of the shift lever, and outputting a corresponding time signal; and
an electronic control unit for calculating a friction element fill time when the shift lever change signal is input in which the friction element fill time is calculated based on a piston stroke ratio of a piston that drives a friction element, wherein the electronic control unit compensates the piston stroke ratio by detecting an N-range hold time and by using the detected N-range hold time and a pre-installed map when an N to D/R shift signal indicating shifting into one of the D- and R-ranges from the N-range is detected, compensates the piston stroke ratio by detecting a D/R-range hold time and using the detected D/R-range hold time and the pre-installed map when a D/R to N shift signal indicating shifting into the N-range from one of the D- and R-ranges is detected, the D/R-range hold time being a time during which the shift range is held at said one of the D- and R-ranges, and calculates a fill time using the compensated piston stroke ratio. - View Dependent Claims (12, 13, 14, 15, 16, 18, 19, 20)
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17. A system for determining a fill time for friction elements in an automatic transmission, the friction elements being actuated by hydraulic pistons, the pistons having at any given time a present stroke and a stroke ratio, the system comprising:
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a shift lever detector adapted to monitor a driver operated transmission shift lever and generate a shift lever change signal in response to movement of the shift lever between gears;
a timer adapted to generate a time signal; and
a control unit including a processor communicating with said shift lever detector and timer to receive said generated signals, wherein the processor is programmed to (a) initialize the timer and present stroke;
(b) detect a N to D/R shift or a D/R to N shift based on signals generated by the shift level detector, and, in response to a detected N to D/R shift execute a first set of instructions, or in response to a detected D/R to N shift execute a second set of instructions, wherein the first set of instructions comprises detecting a N-range hold time and initializing the timer, calculating a change in the N to D/R stroke ratio, compensating for the change in said N to D/R stroke ratio, and calculating a fill time based on the compensated N to D/R stroke ratio; and
the second set of instructions comprises detecting a D/R range hold time and initializing the timer, calculating a change in the D/R to N stroke ratio, compensating for the change in said D/R to N stroke ratio, and calculating a fill time based on the compensated D/R to N stroke ratio.
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Specification