Torque dithering method for controlling a vehicle transmission
First Claim
1. A method of controlling a torque value in a vehicle transmission, comprising the steps of:
- (A) determining a target torque value;
(B) determining an initial current torque value that is indicative of a current transmission condition;
(C) changing the current torque value by filtering a signal that is used for adjusting an engine variable so that the current torque value approaches the target torque value;
(D) determining when the current torque value reaches a preselected value relative to the target torque value; and
(E) cyclically oscillating the current torque value about the target torque value as a function of time having a determined amplitude and period by adjusting an engine variable until a known transmission condition exists.
7 Assignments
0 Petitions
Accused Products
Abstract
A dithering torque control method that is useful for a semi-automated vehicle transmission facilitates accomplishing a desired condition in the transmission. The method is useful during an initial break torque function to relieve drive train torque so that a driver can move a manual shift lever from an engaged position to a transmission neutral position without using a clutch. The method is also useful for shifting a lever to move gearing components from a neutral position to a next desired gear. A dithering function is used to cyclically oscillate a current torque value about a target torque value that is associated with the desired transmission condition. An amplitude and period of the dithering function are determined based upon an overall gear ratio of the transmission. The dithering function begins at a point dependent on a torque value associated with the currently engaged gear. The dithering function continues until a known transmission condition is confirmed.
20 Citations
18 Claims
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1. A method of controlling a torque value in a vehicle transmission, comprising the steps of:
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(A) determining a target torque value; (B) determining an initial current torque value that is indicative of a current transmission condition; (C) changing the current torque value by filtering a signal that is used for adjusting an engine variable so that the current torque value approaches the target torque value; (D) determining when the current torque value reaches a preselected value relative to the target torque value; and (E) cyclically oscillating the current torque value about the target torque value as a function of time having a determined amplitude and period by adjusting an engine variable until a known transmission condition exists. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of controlling a torque value in a vehicle transmission, comprising the steps of:
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(A) determining a target torque value; (B) defining a first condition wherein a current torque value is greater than the target torque value; (C) defining a second condition wherein a current torque value is less than the target torque value; (D) determining whether the first or second condition exists; (E) when the second condition exists, changing the current torque value to a start dithering torque value that is equal to a sum of a determined dither torque value and the target torque value by adjusting an engine variable; (F) when the first condition exists, changing the current torque value to a start dithering torque value that is equal to a difference between the target torque value and a determined dither torque value by adjusting an engine variable; and (G) cyclically oscillating the current torque value about the target torque value as a function over time beginning with the start dithering torque value by adjusting the engine variable, the function having a determined amplitude and period until a determined transmission condition exists. - View Dependent Claims (12, 13)
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14. A method of controlling a torque value in a vehicle transmission, comprising the steps of:
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(A) determining a target torque value; (B) determining a second torque value that is different from the target torque value; (C) determining a current torque value; (D) determining whether the current torque value is above or below the second torque value; (E) changing the current torque value by adjusting an engine variable using a first function when the current torque value is below the second torque value so that the current torque value approaches the target torque value; and (F) changing the current torque value by adjusting an engine variable using a second function when the current torque value is above the second torque value so that the current torque value approaches the target torque value. - View Dependent Claims (15, 16, 17, 18)
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Specification