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Cooling system for working fluid used in automatic transmission of automotive vehicle

  • US 20020128107A1
  • Filed: 01/03/2002
  • Published: 09/12/2002
  • Est. Priority Date: 03/09/2001
  • Status: Active Grant
First Claim
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1. A cooling system for working fluid used in an automatic transmission of an automotive vehicle, comprising:

  • a water-cooled oil cooler and an air-cooled oil cooler connected in series to each other and both disposed in an oil cooler line for cooling the working fluid;

    an oil pump located in the automatic transmission and disposed in the oil cooler line for pressurizing and sending the working fluid into the oil cooler line;

    a hydraulic control circuit disposed downstream of the oil pump for regulating a line pressure produced by the oil pump;

    a lubrication circuit located in the automatic transmission for lubrication of moving transmission parts;

    a first bypass valve that opens to permit the working fluid to circulate via the first bypass valve through the oil pump, the hydraulic control circuit and the lubrication circuit, bypassing the water-cooled oil cooler and the air-cooled oil cooler, only when a working-fluid temperature is less than or equal to a predetermined temperature and the line pressure is greater than or equal to a predetermined pressure; and

    a second bypass valve that opens to permit the working fluid to circulate via the water-cooled oil cooler and the second bypass valve through the oil pump, the hydraulic control circuit and the lubrication circuit, bypassing only the air-cooled oil cooler, only when the working-fluid temperature is less than or equal to a preset temperature value.

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