Vehicle transmission hydraulic circuit fill time learn

Patent metadata

Field	Value
Publication number	US-10260576-B2
Application number	US-201715669123-A
Country	US
Kind code	B2
Filing date	Aug 4, 2017
Priority date	Aug 31, 2016
Publication date	Apr 16, 2019
Grant date	Apr 16, 2019

Abstract

A system for controlling transmission shifting includes a controller that receives a shift request signal and determines if a clutch has been unapplied for more than a predetermined time. With a yes determination, a maximum fill time value for hydraulic fluid to be applied to a clutch control circuit is determined, the maximum fill time value being a function of time the clutch has been unapplied and temperature. A signal indicative of an amount of engine RPM flare after the transmission executes the requested shift is received and a modified maximum fill time value is determined as a function of this flare. The modified maximum fill time value is stored as a replacement for the maximum fill time value for use with a subsequent transmission shifts using this clutch, and reduces an amount of air in the control circuit and an amount of flare with subsequent transmission shifts.

First claim

What is claimed is:

1. A system for controlling shifting of a vehicle transmission, the system comprising:
a transmission including a clutch and a clutch apply circuit having a clutch apply piston, the piston being in fluid communication with a source of pressurized hydraulic fluid configured to be selectively applied to the clutch apply circuit thereby moving the piston and applying the clutch to effect shifting of the transmission; and
a controller configured to:
receive a signal indicative of a request for the transmission to execute a shift;
determine if the clutch has been unapplied for more than a predetermined period of time;
based on determining that the clutch has been unapplied for more than the predetermined period of time, determine a maximum fill time value for the pressurized hydraulic fluid to be applied to the piston to move the clutch to a kiss point, the maximum fill time value being obtained from a set of fill time reference values that are a function of an amount of time the clutch has been unapplied and a temperature of the transmission;
receive a signal indicative of an amount of engine RPM flare after the transmission executes the requested shift using the maximum fill time value; and
determine a modified maximum fill time value as a function of the engine RPM flare, and store the modified maximum fill time value as a replacement for the maximum fill time value in the set of fill time reference values and for use with a subsequent transmission shift request using the same clutch;
wherein the modified maximum fill time value is configured to reduce an amount of air in the hydraulic circuit and an amount of engine RPM flare associated with subsequent transmission shifts using the same clutch.

2. The system of claim 1 , wherein determining a modified maximum fill time value as a function of the amount of engine RPM flare includes:
integrating the received signal indicative of the amount of engine RPM flare to determine an integrated flare control value indicative of an amount of time and energy associated with the amount of engine RPM flare;
obtaining a fill time addition value from a first set of learning reference values that are a function of the integrated flare control value; and
adding the obtained fill time addition value to the stored modified maximum fill time value in the set of fill time reference values for use with subsequent shifts using the same clutch when the clutch has been unapplied for more than the predetermined period of time, such that the stored modified maximum fill time value is continuously learned for subsequent shifts using the same clutch over an operational life of an associated vehicle.

3. The system of claim 1 , wherein based on the controller determining that the clutch has been unapplied for less than the predetermined period of time, the controller is configured to:
determine a fill time value multiplier for the modified maximum fill time value currently stored in the set of fill time reference values, the fill time value multiplier being a function of temperature of the transmission and a number of shifts executed using the clutch during a current run cycle of the transmission and obtained by the controller from a stored set of fill time multiplier reference values.

4. The system of claim 3 , wherein the controller is further configured to:
multiply the modified maximum fill time value currently stored in the set of fill time reference values by the determined fill time value multiplier to determine an adjusted maximum fill time value; and
store the adjusted maximum fill time value as a replacement for the modified maximum fill time value currently stored in the set of fill time reference values such that the adjusted maximum fill time value is continuously learned for subsequent shifts using the same clutch over an operational life of an associated vehicle.

5. The system of claim 4 , wherein the controller is further configured to command application of the pressurized fluid to the clutch apply circuit using the adjusted maximum fill time value to execute the desired shift using the clutch.

6. The system of claim 4 , wherein the determined fill time value multiplier is a number between zero and one and is configured to decay increased fill time for the hydraulic circuit over the course of subsequent shifts.

7. The system of claim 6 , wherein the controller is configured to:
receive a signal indicative of an amount of engine RPM flare based on the transmission executing the requested shift using the adjusted maximum fill time value;
integrate the received signal indicative of the amount of engine RPM flare based on the transmission executing the requested shift using the adjusted maximum fill time value to determine another integrated flare control value; and
obtain a filter modifier value from a second set of learning reference values that are a function of the another integrated flare control value.

8. The system of claim 7 , wherein the controller is further configured to:
multiply the obtained fill time value multiplier by the obtained filter modifier value and store the resultant value in the set of fill time multiplier reference values as a replacement for the obtained fill time value multiplier such that the stored set of fill time value multipliers are continually learned based on engine RPM flare associated with subsequent transmission shifts using the same clutch when this clutch has been unapplied for more than the predetermined period of time.

Assignees

• Saliga Nathan J
• Rangarajan Rahul
• Ross Jeffrey E
• Fca Us Llc

Inventors

• Saliga Nathan J
• Rangarajan Rahul
• Ross Jeffrey E

Classifications

• Y10T477/69362

  Cross-Sectional Technologies · mapped topic

• F16D2500/304

  from the clutch · CPC title

• Y10T477/653

  Cross-Sectional Technologies · mapped topic

• F16D25/062

  the clutch having friction surfaces · CPC title

• F16D2500/3067

  Speed of the engine · CPC title