Automatic range up-shift control and method of operation

Abstract

A control for enhanced range shifting in a computer (48) assisted vehicular compound transmission having a main section (16A) shifted by a manually operated shift lever (31) and a range section (16B) shifted in response to operation of a range shift selector, such as sensing shift lever (31) passing through a predetermined actuation point (AR) in the shift pattern. During a compound up-shift, if the vehicle reaches a speed greater than a predetermined value during a coasting condition and the shift lever is in a low range neutral position, then the range section up-shift is automatically completed without undue wear or damage to the range section synchronized clutch (130). It is emphasized that this abstract is provided to comply with the rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. 37 CFR 1.72(b).

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a control system / method for controlling range shifting in a compound transmission having a lever-shifted main section and a range section shifted by a range section actuator for selectively positioning a synchronized double-acting positive clutch. The transmission may also have a splitter section. In particular, the present invention relates to controlling range shifting in a lever-shifted, partially automated vehicular transmission system having a microprocessor-based controller for controlling the operation of a range shift actuator and / or an engine fuel control. [0003] 2. Description of the Related Art [0004] Controller-assisted, manually shifted transmission systems are known in the prior art, as may be seen by reference to U.S. Pat. Nos. 5,582,558; 5,755,639; 5,766,111; 5,791,189; 5,974,906; 5,989,155 and 6,015,366, the disclosures of which are incorporated herein by reference. ...

AI Technical Summary

Benefits of technology

[0010] In accordance with the present invention, the drawbacks of the prior art are minimized or overcome by the provision of a range shift control for a computer-assisted mechanical transmission system that will sense vehicle operating conditions and will avoid unacceptable range up-shifts to prevent and / or minimize undue wear and / or damage to the high speed range synchronizer during a range up-shift. This is accomplished by causing range up-shifts to occur before the vehicle speed becomes unacceptably high. A range up-shift to a high range is automatically made if (i) a range up-shift has not been already initiated, (ii) a position of a shift lever is in a low range neutral position, and (iii) a vehicle speed is greater than a predetermined value, thereby preventing and / or minimizing undue wear and / or damage to the range synchronizer during a range up-shift. If a range upshift has already been initiated, then established shift protocols are invoked to complete the up-shift. Otherwise, the system continues to monitor the specified conditions to determine the need for an up-shift.

Problems solved by technology

This is accomplished by causing range up-shifts to occur before the vehicle speed becomes unacceptably high.

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