Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Transmission control
Reexamination Certificate
1999-07-19
2001-01-23
Nguyen, Tan (Department: 3661)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Transmission control
C701S055000, C477S078000
Reexamination Certificate
active
06178366
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to improved shift logic for an automated vehicular mechanical transmission system. In particular, the present invention relates to a control method/system having logic rules whereby in the automatic shifting mode, upshifts are initiated normally as a function of throttle position (demand) but, under certain conditions, are initiated as a function of engine torque and not of throttle position (demand).
2. Description of the Prior Art
Fully and partially automated vehicular mechanical transmission systems are known in the prior art, as may be seen by reference to U.S. Pat. Nos. 4,361,060; 4,595,986; 4,648,290; 4,850,236; 5,109,721; 5,393,276; 5,409,432 and 5,425,284, the disclosures of which are incorporated herein by reference. Such transmissions having an automatic shift mode typically base shift decisions upon shift point profiles or shift schedules, which often are graphically represented on a graph of throttle position (demand) versus engine, output shaft or vehicle speed. It is known to temporarily modify these shift profiles in view of various sensed vehicle operating conditions to modify vehicle performance, for antihunt purposes or the like. Examples of such shift logic may be seen by reference to U.S. Pat. Nos. 4,361,060; 4,551,802; 4,852,006; 4,916,979; 5,053,963 and 5,406,861, the disclosures of which are incorporated herein by reference.
While the prior art systems which based upshift decisions on demand usually responded to the driver's intent in most situations, a problem not addressed by the prior art shift logic involves systems which will cause engine torque to be significantly restricted, regardless of throttle position, under certain operating conditions. These systems include all-speed governors, road-speed governors (when maximum ground speed is being approached), gear-down protection, etc. When these systems are active to significantly restrict engine torque regardless of a relative high throttle position, basing upshift decisions on demand will delay upshifting, usually in opposition to the driver's intent.
SUMMARY OF THE INVENTION
In accordance with the present invention, a new and improved automated change-gear shift control, including improved upshift initiation control logic, is provided.
This is accomplished by providing logic rules whereby, under at least certain operating conditions, the normally utilized, demand-based upshift schedule is replaced by an engine torque-based upshift schedule. By way of example, if the actual torque being developed by the engine is less than of predetermined percentage (such as, for example, 25-50%) of the torque being requested by the throttle position, then upshift initiation decisions will be based on engine torque rather than on demand.
Accordingly, it is an object of the present invention to provide a new and improved automated change-gear transmission shift control system/method.
This and other objects and advantages of the present invention will become apparent from a reading of the following description of the preferred embodiment taken in connection with the attached drawings.
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Genise Thomas A.
Janecke Daniel P.
Von Oeyen Eric J.
Eaton Corporation
Gordon Howard D.
Nguyen Tan
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