System for controlling a continuously variable transmission of a motor vehicle
First Claim
1. In a system for controlling a solenoid operated control valve in a continuously variable transmission to transmit power of an internal combustion engine to driving wheels of a motor vehicle, said transmission having a drive pulley including a hydraulically shiftable disc and a first hydraulic cylinder for shifting said disc, a driven pulley including a hydraulically shiftable disc and a second hydraulic cylinder for operating said disc of said driven pulley, a belt engaged with both pulleys, said control system having a solenoid for operating said solenoid operated control valve, and a control unit for controlling dither exciting current fed to said solenoid and for producing a basic exciting current signal, an improvement of the system which comprises:
- dither means responsive to said basic exciting current signal for providing a dither and for generating a dither signal;
calculating means responsive to said dither signal for adding said dither to said basic exciting current and for producing said dither exciting current signal;
integration means responsive to said dither exciting current signal for integrating deviation of said dither exciting current from said basic exciting current and for producing a integral signal;
correction means responsive to said integral signal for producing a correction value dependent on said integrals and for generating a correction signal;
said dither means responsive to said correction signal for correcting said dither and for producing a corrected dither signal; and
said calculating means responsive to said corrected dither signal for producing a corrected dither exciting current for exciting said solenoid so as to accurately control valve without fluctuation.
1 Assignment
0 Petitions
Accused Products
Abstract
A control unit of a CVT is provided to produce a basic exciting current for the dither exciting current fed to a solenoid of the solenoid operated control valve. A dither is added to the basic exciting current for producing the dither exciting current. A positive deviation and a negative deviation of the dither exciting current from the basic exciting current in one cycle of the dither is integrated for producing integrals. A correction value which renders the sum of said integrals zero is produced. The correction value is added to the dither so that a corrected dither exciting current is produced.
63 Citations
3 Claims
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1. In a system for controlling a solenoid operated control valve in a continuously variable transmission to transmit power of an internal combustion engine to driving wheels of a motor vehicle, said transmission having a drive pulley including a hydraulically shiftable disc and a first hydraulic cylinder for shifting said disc, a driven pulley including a hydraulically shiftable disc and a second hydraulic cylinder for operating said disc of said driven pulley, a belt engaged with both pulleys, said control system having a solenoid for operating said solenoid operated control valve, and a control unit for controlling dither exciting current fed to said solenoid and for producing a basic exciting current signal, an improvement of the system which comprises:
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dither means responsive to said basic exciting current signal for providing a dither and for generating a dither signal; calculating means responsive to said dither signal for adding said dither to said basic exciting current and for producing said dither exciting current signal; integration means responsive to said dither exciting current signal for integrating deviation of said dither exciting current from said basic exciting current and for producing a integral signal; correction means responsive to said integral signal for producing a correction value dependent on said integrals and for generating a correction signal; said dither means responsive to said correction signal for correcting said dither and for producing a corrected dither signal; and said calculating means responsive to said corrected dither signal for producing a corrected dither exciting current for exciting said solenoid so as to accurately control valve without fluctuation. - View Dependent Claims (2, 3)
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Specification