The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 04, 1996
Filed:
May. 05, 1994
Ralph W Baxter, Ft. Wayne, IN (US);
Randy L Sommer, Monroeville, IN (US);
Dana Corporation, Toledo, OH (US);
Abstract
The invention is directed to a four-wheel drive system for a vehicle having front and rear drive wheels driven by an engine and transmission assembly, and including a transfer case having a torque input shaft for receiving output torque from the vehicle engine and transmission assembly. A transfer gear assembly of the transfer case provides low and high speed power paths, and a shift mechanism is provided to shift between the low and high speed power paths. The system further includes an engine control module for controlling the engine fuel system and shifting of the transmission assembly between a plurality of vehicle gear ratios. A transfer case control module controls the shift mechanism for shifting between the low and high speed power paths. The transfer case control module is connected to the engine control module, and controls shifting between the low and high speed power paths by selectively controlling the engine fuel system to modify torque supplied to the transfer case, and/or shifting of the transmission assembly. The transfer case control module will thereafter shift the transfer case to a selected high or low speed power path when the output speed of the transmission assembly matches the output speed of the transfer case. The system allows the transfer case to be shifted from low range to high range or vice versa on-the-fly, while the vehicle is still moving and under power. The invention also provides a method of shifting a four-wheel drive system between low range and high range drive modes on-the-fly.