Automatic transmission clutch timing optimization apparatus and method
First Claim
1. A method for use with an automatic transmission having an off-going clutch and an on-coming clutch during a speed ratio shift event, the method comprising:
- controlling the off-going clutch using closed loop control to maintain a predetermined slip threshold, said controlling the off-going clutch including generating an off-going clutch pressure command to which the off-going clutch is responsive and that varies with respect to time;
causing the on-coming clutch to gain torque capacity during said controlling the off-going clutch;
determining the first derivative with respect to time of at least a portion of the off-going clutch pressure command; and
determining when the on-coming clutch gained torque capacity using the first derivative.
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Accused Products
Abstract
A method for determining when in the course of a shift event an on-coming clutch gains torque capacity is provided. The method includes closed-loop controlling an off-going clutch to maintain a predetermined slip threshold by generating an off-going clutch pressure command, causing the on-coming clutch to engage during the closed loop control of the off-going clutch, generating a first derivative with respect to time of the off-going clutch pressure command, and using the first derivative to determine when the on-coming clutch gained torque capacity. A neural network method is preferably employed in analyzing the first derivative to locate a transition in the rate of commanded pressure indicative of off-going clutch release. A corresponding apparatus is also provided.
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Citations
11 Claims
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1. A method for use with an automatic transmission having an off-going clutch and an on-coming clutch during a speed ratio shift event, the method comprising:
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controlling the off-going clutch using closed loop control to maintain a predetermined slip threshold, said controlling the off-going clutch including generating an off-going clutch pressure command to which the off-going clutch is responsive and that varies with respect to time;
causing the on-coming clutch to gain torque capacity during said controlling the off-going clutch;
determining the first derivative with respect to time of at least a portion of the off-going clutch pressure command; and
determining when the on-coming clutch gained torque capacity using the first derivative. - View Dependent Claims (2, 3, 4, 5)
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6. A control apparatus for an automatic transmission having an input shaft and an output shaft;
- a first clutch and a second clutch;
a first and second fill chamber to which hydraulic fluid is supplied for hydraulic actuation of the first and second clutch, respectively;
a first and second actuator configured to selectively allow pressurized fluid into the first and second fill chamber, respectively;
wherein the first clutch and the second clutch are operatively connected between the input shaft and the output shaft to effect a speed ratio change during a shift event by disengagement of the first clutch and engagement of the second clutch, the control apparatus comprising;
a controller operatively connected to the first actuator and the second actuator to cause selective disengagement and engagement of the first and second clutches, respectively;
wherein the controller is programmed and configured to determine the speed ratio between the input shaft and the output shaft in order to determine the existence of a predetermined slip threshold at the first clutch;
wherein the controller is programmed and configured to control the off-going clutch during the shift event using closed loop control to maintain the predetermined slip threshold by generating an off-going clutch pressure command to which the first clutch is responsive and that varies with respect to time;
wherein the controller is programmed and configured to cause the on-coming clutch to gain torque capacity during the shift event;
wherein the controller is programmed and configured to determine the first derivative with respect to time of at least a portion of the off-going clutch pressure command; and
wherein the controller is programmed and configured to determine when the on-coming clutch gained torque capacity using the first derivative. - View Dependent Claims (7, 8, 9, 10)
- a first clutch and a second clutch;
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11. A method for use with an automatic transmission having an off-going clutch and an on-coming clutch during a speed ratio shift event, the on-coming clutch being characterized by hydraulic actuation when an apply chamber is filled with sufficiently pressurized fluid, the method comprising:
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controlling the off-going clutch using closed loop control to maintain a predetermined slip threshold, said controlling the off-going clutch including generating an off-going clutch pressure command to which the off-going clutch is responsive and that varies with respect to time;
causing the on-coming clutch to gain torque capacity by supplying fluid to the apply chamber during said controlling the off-going clutch;
determining the first derivative with respect to time of at least a portion of the off-going clutch pressure command, said first derivative being characterized by local minima and maxima;
generating a set of data points, each of the data points including a time value and a first derivative value of one of the local minima or maxima;
classifying each of the data points into one of a first group and a second group using a k-means algorithm, the data points in the second group having later time values than the data points in the first group;
determining the data point having the earliest time value in the second group; and
determining a measure of the total volume of fluid supplied to the apply chamber at the data point having the earliest time value in the second group.
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Specification