Method of controlling engagement of a starting clutch in an automatic transmission during vehicle launch
First Claim
Patent Images
1. A method of controlling engagement of a starting clutch for a transmission connected to an engine, the method comprising:
- providing a feed-forward input command as a function of an engine operating parameter;
providing a feed-back input command as a function of measured clutch slip determined from transmission input speed and transmission output speed;
wherein said step of providing a feed-back input command further comprises;
comparing said measured clutch slip with a reference slip profile which includes a low speed stage in which slip is a function of engine speed such that slip increases along with engine speed to allow the engine to quickly achieve high torque, and a high speed stage in which slip is a function of vehicle speed such that slip decreases as vehicle speed increases until a final desired relatively low slip is reached; and
providing the feed-back input command based upon said comparison with the reference slip profile; and
summing said feed-forward input command and said feed-back input command to determine a clutch control command for controlling engagement of the starting clutch.
13 Assignments
0 Petitions
Accused Products
Abstract
A control strategy is provided for controlling engagement of a clutch during vehicle launch. A feed-back input command and a feed-forward input command are utilized and summed to determine a clutch control command. The feed back input command uses a reference slip profile having a low speed portion and a high speed portion. In the low speed portion, the slip is a function of engine speed. In the high speed portion, the slip is a function of transmission output speed or vehicle speed.
20 Citations
15 Claims
-
1. A method of controlling engagement of a starting clutch for a transmission connected to an engine, the method comprising:
-
providing a feed-forward input command as a function of an engine operating parameter; providing a feed-back input command as a function of measured clutch slip determined from transmission input speed and transmission output speed;
wherein said step of providing a feed-back input command further comprises;comparing said measured clutch slip with a reference slip profile which includes a low speed stage in which slip is a function of engine speed such that slip increases along with engine speed to allow the engine to quickly achieve high torque, and a high speed stage in which slip is a function of vehicle speed such that slip decreases as vehicle speed increases until a final desired relatively low slip is reached; and providing the feed-back input command based upon said comparison with the reference slip profile; and summing said feed-forward input command and said feed-back input command to determine a clutch control command for controlling engagement of the starting clutch. - View Dependent Claims (2, 3, 4, 5, 6, 7)
-
-
8. A method of controlling engagement of a starting clutch for a transmission connected to an engine, the method comprising:
-
providing a feed-forward input command as a function of an engine operating parameter; measuring clutch slip; comparing said measured clutch slip with a reference slip profile to provide a feed-back input command, wherein said reference sun profile includes a low speed stage in which slip is a function of en nine speed such that slip increases along with engine speed during launch to allow the engine to quickly achieve high torque, and a high speed stage in which slip is a function of vehicle speed such that slip decreases as vehicle speed increases until a final desired relatively low slip is reached; and summing said feed-forward input command and said feed-back input command to determine a clutch control command for controlling engagement of the starting clutch. - View Dependent Claims (9, 10, 11, 12, 13)
-
-
14. A method of controlling engagement of a starting clutch for a transmission connected to an engine having a throttle, wherein the transmission is characterized by the absence of a torque converter, the method comprising:
-
providing a feed-forward input command as a function of position of the throttle; providing a feed-back input command based upon a measured clutch slip determined from transmission input speed and transmission output speed; summing said feed-forward input command and said feed-back input command to determine a clutch control command for controlling engagement of the starting clutch; wherein said step of providing a feed-back input command further comprises; comparing said measured clutch slip with a reference slip profile which includes a low speed stage in which slip is a function of engine speed such that slip increases along with engine speed to allow the engine to quickly achieve high torque, and a high speed stage in which slip is a function of vehicle speed such that slip decreases as vehicle speed increases until a final desired relatively low slip is reached; and providing the feed-back input command based upon said comparison with the reference slip profile; and wherein the starting clutch is an input clutch positioned between the engine and the transmission. - View Dependent Claims (15)
-
Specification