Transmission detent shift control with acceleration-based compensation
First Claim
1. In a motor vehicle powertrain having an engine connected to drive a vehicle through an automatic shift transmission, the powertrain operating in a detent mode when an engine load indicator exceeds a predefined threshold, a method of operation for initiating upshifting of said transmission during said detent mode, comprising the steps of:
- measuring an acceleration of said engine;
retrieving a delay time from a table of empirically determined time intervals corresponding to a period between initiation of an upshift and achievement of a peak engine speed during such upshift;
determining an engine speed change which is expected to occur in the course of said retrieved delay time based on said measured acceleration;
developing a trigger speed reference in relation to a difference between said determined engine speed change and a limit speed of said engine; and
initiating an upshift of said transmission when said engine achieves a speed at least as great as said trigger speed reference, whereby the peak engine speed achieved during said upshift substantially coincides with said limit speed of said engine.
13 Assignments
0 Petitions
Accused Products
Abstract
An improved detent shift control in which upshift initiation is adjusted in relation to the engine acceleration and the expected shift delay time so that the engine speed limit is not exceeded. Data recorded in the course of the shift is analyzed upon completion of the shift, and the control adaptively adjusts the expected delay time if a significant timing error is detected. Whenever the engine throttle position exceeds a detent threshold, a shift trigger speed for the next higher gear is determined by subtracting a delay-based speed from the desired engine shift speed. The delay-based speed is determined according to the product of the engine acceleration and the stored delay time. The shift is initiated when the engine speed reaches the trigger speed so that the engine speed is prevented from exceeding the desired shift speed. If data collected during the shift reveals that the actual shift speed significantly deviated from the desired shift speed, the controller develops and stores a temperature-based adaptive delay time correction for that shift type. In subsequent detent upshifting to the same gear, the delay time correction is combined with the stored empirical delay time in the determination of the shift trigger speed.
25 Citations
9 Claims
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1. In a motor vehicle powertrain having an engine connected to drive a vehicle through an automatic shift transmission, the powertrain operating in a detent mode when an engine load indicator exceeds a predefined threshold, a method of operation for initiating upshifting of said transmission during said detent mode, comprising the steps of:
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measuring an acceleration of said engine; retrieving a delay time from a table of empirically determined time intervals corresponding to a period between initiation of an upshift and achievement of a peak engine speed during such upshift; determining an engine speed change which is expected to occur in the course of said retrieved delay time based on said measured acceleration; developing a trigger speed reference in relation to a difference between said determined engine speed change and a limit speed of said engine; and initiating an upshift of said transmission when said engine achieves a speed at least as great as said trigger speed reference, whereby the peak engine speed achieved during said upshift substantially coincides with said limit speed of said engine. - View Dependent Claims (2, 3, 4)
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5. In a motor vehicle powertrain having an engine connected to drive a vehicle through an automatic shift transmission, the powertrain operating in a detent mode when an engine load indicator exceeds a predefined threshold, control apparatus for initiating upshifting of said transmission during said detent mode, comprising:
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means for measuring an acceleration of said engine prior to upshift initiation; base look-up means for storing an empirically determined set of delay times corresponding to a time interval between initiation of an upshift and achievement of peak engine speed during such upshift; means for determining an engine speed change which is expected to occur in the course of said time interval based on said measured acceleration and a base delay time obtained from said base look-up means; means for developing a trigger speed reference in relation to a difference between the determined engine speed change and a limit speed of said engine; and means for initiating an upshift of said transmission when said engine achieves a speed at least as great as said trigger speed reference, whereby the peak engine speed achieved during such upshift substantially coincides with said limit speed of said engine. - View Dependent Claims (6, 7, 8, 9)
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Specification