Lock-up control and method thereof
First Claim
1. A lock-up control system for a lock-up type automatic transmission for a vehicle having an engine, the automatic transmission including a lock-up type torque converter having an input element drivingly connected to the engine, an output element and a bridge clutch which, when engaged, mechanically interconnects the input element and the output element, said lock-up control system, comprising:
- means for detecting a command for shifting in the automatic transmission and generating a shifting command indicative signal;
means responsive to said shifting command indicative signal for temporarily releasing engagement of the bridge clutch;
means for estimating an engine revolution speed after an instant when the bridge clutch is temporarily released and generating an estimated engine revolution speed indicative signal;
means for detecting an actual engine revolution speed and generating an actual engine revolution speed indicative signal;
means for integrating a difference between said estimated engine revolution speed indicative signal and said actual engine revolution speed indicative signal to give an integral value and generating an integral value indicative signal; and
means for determining said instant in such a manner as to decrease a difference between said integral value and a predetermined value.
1 Assignment
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Accused Products
Abstract
A lock-up control wherein a temporary release timing of a bridge clutch is adjusted by learning control. According to the learning control, a difference between an estimated engine revolution speed after an instant when the bridge clutch is temporarily released and an actual engine revolution speed is obtained, an integral value is obtained by integrating the difference, and the temporary release timing is adjusted or corrected in such a manner as to decrease a difference between the integral value and a predetermined value.
22 Citations
6 Claims
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1. A lock-up control system for a lock-up type automatic transmission for a vehicle having an engine, the automatic transmission including a lock-up type torque converter having an input element drivingly connected to the engine, an output element and a bridge clutch which, when engaged, mechanically interconnects the input element and the output element, said lock-up control system, comprising:
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means for detecting a command for shifting in the automatic transmission and generating a shifting command indicative signal; means responsive to said shifting command indicative signal for temporarily releasing engagement of the bridge clutch; means for estimating an engine revolution speed after an instant when the bridge clutch is temporarily released and generating an estimated engine revolution speed indicative signal; means for detecting an actual engine revolution speed and generating an actual engine revolution speed indicative signal; means for integrating a difference between said estimated engine revolution speed indicative signal and said actual engine revolution speed indicative signal to give an integral value and generating an integral value indicative signal; and means for determining said instant in such a manner as to decrease a difference between said integral value and a predetermined value. - View Dependent Claims (2, 3, 4, 5)
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6. A method for controlling a lock-up in a lock-up type automatic transmission for a vehicle having an engine, the automatic transmission including a lock-up type torque converter having an input element drivingly connected to the engine, an output element and a bridge clutch which, when engaged, mechanically interconnects the input element and the output element, said lock-up control system, comprising the steps of:
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detecting a command for shifting in the automatic transmission and generating a shifting command indicative signal; temporarily releasing engagement of the bridge clutch responsive to said shifting command indicative signal; estimating an engine revolution speed after an instant when the bridge clutch is temporarily released and generating an estimated engine revolution speed indicative signal; detecting an actual engine revolution speed and generating an actual engine revolution speed indicative signal; integrating a difference between said estimated engine revolution speed indicative signal and said actual engine revolution speed indicative signal to give an integral value and generating an integral value indicating signal; and determining said instant in such a manner as to decrease a difference between said integral value and a predetermined value.
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Specification