Shift synchronization using decaying torque
First Claim
1. A method of engaging and disengaging transmission gears in a vehicle comprising the steps of:
- (a) processing an initial torque representing an engine torque;
(b) processing an estimated zero torque representing an estimate of a transmission output shaft torque;
(c) setting a high and low band torque wherein the estimated zero torque is between the high and low band torques;
(d) comparing the initial torque to the high band torque and increasing the engine torque to the high band torque if the initial torque is less than the high band torque;
(e) beginning to urge a gear out of engagement when the engine torque is at the greater of the initial torque and high band torque; and
(f) decaying the engine torque from the higher of the initial torque and high band torque to the low band torque to facilitate engaging and disengaging transmission gears.
5 Assignments
0 Petitions
Accused Products
Abstract
A method of engaging and disengaging transmission gears in a vehicle is provided. A controller processes an initial torque representing an engine torque and an estimated zero torque representing an estimate of a transmission output shaft torque. The controller also sets a high and low band torque about the estimated zero torque. Once the above torques have been determined, the controller compares the initial torque to the high band torque. If the initial torque is below the high band torque, the controller increases the engine torque to the high band torque. If the initial torque is greater than the high band torque, then no preliminary adjustments to the engine torque need be made. At least one shift valve is energized when the engine torque is equal to or greater than the high band torque. The engine torque is decayed by the controller to the low band torque to facilitate engaging and disengaging transmission gears.
16 Citations
13 Claims
-
1. A method of engaging and disengaging transmission gears in a vehicle comprising the steps of:
-
(a) processing an initial torque representing an engine torque; (b) processing an estimated zero torque representing an estimate of a transmission output shaft torque; (c) setting a high and low band torque wherein the estimated zero torque is between the high and low band torques; (d) comparing the initial torque to the high band torque and increasing the engine torque to the high band torque if the initial torque is less than the high band torque; (e) beginning to urge a gear out of engagement when the engine torque is at the greater of the initial torque and high band torque; and (f) decaying the engine torque from the higher of the initial torque and high band torque to the low band torque to facilitate engaging and disengaging transmission gears. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
-
-
9. A vehicle drive system comprising:
-
an engine having an engine output shaft with an engine torque; a transmission having a transmission input shaft coupled to said engine output shaft and a transmission output shaft selectively coupled to said transmission input shaft by a plurality of gears; an intent switch for preparing to shift said transmission between said plurality of gears; an actuator for shifting between said plurality of gears when said intent switch is actuated; and a controller programmed to process an initial engine torque parameter, a zero torque parameter representing a transmission output shaft torque, and high and low band torque parameters wherein said zero torque parameter is between said high and low band torque parameters, said controller programmed to compare said initial engine torque parameter to said high band torque parameter and send a signal to increase said engine torque to said high band torque parameter if said initial engine torque parameter is less than said high band torque parameter, said controller programmed to energize said actuator when said engine torque is at the greater of said initial engine torque and high band torque parameters, and said controller programmed to decay said engine torque toward said low band torque parameter to facilitate engaging and disengaging transmission gears. - View Dependent Claims (10, 11, 12, 13)
-
Specification