Wet start clutches put new, more severe, requirements on the lubricants used in these transmissions. The fluids must provide the correct friction versus velocity characteristics to prevent clutch shudder and maintain those characteristics for long periods of time to allow extended drain intervals for the fluids. While many methods exist for characterizing the frictional behaviour of clutch materials and fluids under conditions of high energy engagements, no standard test exists for measuring the friction durability of transmission fluids in a mixed operational mode of high energy engagements and sliding for long periods of time at low speeds. In response to the need for a test to assess friction durability requirements of torque converters with regulated clutches (GWK) the authors have developed a test method using a modified SAE2 machine. A test cycle was developed in which the clutch is slipped under steady state conditions for 50 minutes. A program was begun to develop a new friction system that would allow for significantly longer friction control than the conventional friction systems used in ATF-1 and ATF-2. This program yielded a family of friction modifying chemicals that can be treated at concentrations over ten times that of conventional friction modifiers.


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    Title :

    Formulating fluids with improved friction durability for wet start clutches


    Additional title:

    Schmierstoffe mit erhöhter Reibungsfestigkeit für Anfahr-Nasskupplungen


    Contributors:

    Published in:

    Publication date :

    2004


    Size :

    12 Seiten, 10 Bilder, 3 Tabellen, 3 Quellen




    Type of media :

    Conference paper


    Type of material :

    Print


    Language :

    English




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