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Lockup controlling system for variable speed, automatic transmission

  • US 4,393,467 A
  • Filed: 08/26/1980
  • Issued: 07/12/1983
  • Est. Priority Date: 09/01/1979
  • Status: Expired due to Term
First Claim
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1. A lockup controlling system for an automatic, variable speed transmission including a directly coupled clutch and a hydraulic circuit including a fluid path switching means and solenoid valve means which causes the engagement and disengagement of the directly coupled clutch comprising:

  • first means for sensing an operating condition of the transmission and for producing a first signal in accordance therewith;

    second means for sensing an operating condition of an engine to which the transmission is coupled and for producing a second signal in accordance therewith;

    solenoid driver means for selectively energizing or deenergizing the solenoid valve means in response to a solenoid control signal; and

    electronic control means including means for storing reference data in the form of one of the operating condition of the transmission and the operating condition of the engine, addressed by the form of the other of the operating condition of the transmission and the operating condition of the engine, and indicative of boundaries between regions where a lockup operation of the transmission is advantageous and regions where the lockup is advantageously terminated, said reference data being provided for a plurality of speed stages;

    means for reading said first and second signals;

    means for reading out reference data addressed by one of said first and second signals and comparing the other of said first and second signals with the read-out reference data to provide a solenoid control signal for energizing or deenergizing the solenoid valve means.

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