Shift shock suppressing system for automotive power train
First Claim
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1. A shift shock suppressing system for an automotive power train including an engine and an automatic transmission mounted on a vehicle, comprising:
- shifting control means for performing shift control for said automatic transmission depending upon an operating condition of the engine and a traveling condition of the vehicle;
torque varying means for varying an output torque of the engine;
shifting state detecting means for detecting on-going shifting state of the automatic transmission controlled by said shift control means;
shift shock suppression control means for outputting a command lowering of the output torque of said engine to said torque varying means when initiating of down-shifting is detected by said shifting state detecting means, and when a first predetermined period is elapsed from detection of initiation of down-shifting, and maintaining the command for a second predetermined period;
arithmetic means for deriving a variation rate of an engine speed after initiation of down-shifting;
judgement means for judging whether a down-shifting is completed on the basis of an input from said arithmetic means;
measuring means for measuring a shifting period as a period from initiation of down-shifting to completion of down-shifting as judged by said judgement means; and
learning control means for modifying said first predetermined period with a value derived by subtracting a preliminarily set third predetermined period from said shifting period derived by said measuring means.
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Abstract
When on-going down-shifting state of an automatic transmission is detected, an output torque of an engine is lowered after expiration of a first predetermined period, which is set between detection of down-shifting and a timing immediately before completion of down shifting, and for a second predetermined period which is set for a given period to completion of down-shifting from expiration of the first predetermined period to suppress a shift shock.
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Citations
9 Claims
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1. A shift shock suppressing system for an automotive power train including an engine and an automatic transmission mounted on a vehicle, comprising:
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shifting control means for performing shift control for said automatic transmission depending upon an operating condition of the engine and a traveling condition of the vehicle; torque varying means for varying an output torque of the engine; shifting state detecting means for detecting on-going shifting state of the automatic transmission controlled by said shift control means; shift shock suppression control means for outputting a command lowering of the output torque of said engine to said torque varying means when initiating of down-shifting is detected by said shifting state detecting means, and when a first predetermined period is elapsed from detection of initiation of down-shifting, and maintaining the command for a second predetermined period; arithmetic means for deriving a variation rate of an engine speed after initiation of down-shifting; judgement means for judging whether a down-shifting is completed on the basis of an input from said arithmetic means; measuring means for measuring a shifting period as a period from initiation of down-shifting to completion of down-shifting as judged by said judgement means; and learning control means for modifying said first predetermined period with a value derived by subtracting a preliminarily set third predetermined period from said shifting period derived by said measuring means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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Specification