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U.S. Department of Energy
Office of Scientific and Technical Information

Transmission ratio control system for a continuously variable transmission

Patent ·
OSTI ID:5584519
This patent describes a control system for a continuously variable transmission for transmitting the power of an internal combustion engine to driving wheels of a motor vehicle through a clutch, having a drive pulley including a hydraulically shiftable disc and a first hydraulic cylinder for shifting the disc. A driven pulley includes a hydraulically shiftable disc and a second hydraulic cylinder for operating the disc of the driven pulley. A belt is engaged with both pulleys. A transmission ratio control valve has ports and a spool and a line pressure control valve has ports and a spool. A first hydraulic circuit has a pump for supplying oil to the first and second cylinders through the line pressure control valve which controls line pressure and the transmission ratio control valve. The system comprises: detecting means for detecting load on the engine and for producing a load signal; first means responsive to the load signal for producing a desired line pressure signal; second means responsive to the desired line pressure signal for shifting the spool of the line pressure control valve so as to provide control the line pressure; detecting means for detecting a stop of the vehicle and producing a stop signal; third means responsive to the stop signal for increasing the line pressure so as to operate the second hydraulic cylinder to increase the transmission ratio.
Assignee:
Fuji Jukogyo Kabushiki Kaisha, Tokyo
Patent Number(s):
US 4708031
OSTI ID:
5584519
Country of Publication:
United States
Language:
English