Abstract:
A torque converter clutch (TCC) release fluid lubrication system for a motor vehicle transmission includes a first fluid line, a second fluid line and a third fluid line. The first fluid line supplies TCC apply fluid to the TCC. The second fluid line receives TCC release fluid from the TCC. And the third fluid line supplies a first lubrication fluid to the transmission. The TCC release fluid and the first lubrication fluid combine into a second lubrication fluid that is fed into the transmission.

Description:
FIELD 
     The present disclosure relates to a lubrication system for a motor vehicle transmission. More specifically, the present disclosure relates to release fluid from a torque converter clutch that provides further lubrication fluid to the transmission. 
     BACKGROUND 
     The statements in this section merely provide background information related to the present disclosure and may or may not constitute prior art. 
     A typical automatic transmission includes a hydraulic control system that is employed to provide cooling and lubrication to components within the transmission and to actuate a plurality of torque transmitting devices. These torque transmitting devices may be, for example, friction clutches and brakes arranged with gear sets or in a torque converter. The conventional hydraulic control system generally includes a main pump that provides a pressurized fluid, such as oil, to a plurality of valves and solenoids within a valve body. The main pump is driven by the engine of the motor vehicle. The valves and solenoids are operable to direct the pressurized hydraulic fluid through a hydraulic fluid circuit to various subsystems including lubrication subsystems, cooler subsystems, torque converter clutch control subsystems, and shift actuator subsystems that include actuators that engage the torque transmitting devices. The pressurized hydraulic fluid delivered to the shift actuators is used to engage or disengage the torque transmitting devices in order to obtain different gear ratios. 
     While previous hydraulic control systems are useful for their intended purpose, the need for new and improved hydraulic control system configurations within transmissions which exhibit improved performance, especially from the standpoints of efficiency, responsiveness and smoothness, is essentially constant. Accordingly, there is a need for an improved, cost-effective hydraulic control system for use in a hydraulically actuated automatic transmission. 
     SUMMARY 
     A torque converter clutch (TCC) release fluid lubrication system for a motor vehicle transmission includes a first fluid line, a second fluid line and a third fluid line. The first fluid line supplies TCC apply fluid to the TCC. The second fluid line receives TCC release fluid from the TCC. And the third fluid line supplies a first lubrication fluid to the transmission. The TCC release fluid and the first lubrication fluid combine into a second lubrication fluid that is fed into the transmission. 
     Further features, advantages, and areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
    
    
     
       DRAWINGS 
       The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. Moreover, in the figures, like reference numerals designate corresponding parts throughout the views. In the drawings: 
         FIG. 1  is a diagram of part of a lubrication system of a motor vehicle transmission; and 
         FIG. 2  is a flow diagram of a process for operating the lubrication system shown in  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
     The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. 
     Referring now to the drawings, a system for lubrication a motor vehicle transmission embodying the principles of the present invention is illustrated in  FIG. 1  and designated at  10 . The system  10  is operable to control torque transmitting mechanisms, such as synchronizers, clutches, and brakes within a transmission, as we as providing lubrication and cooling to components within the transmission and to control a torque converter coupled to the transmission. The system  10  includes a plurality of interconnected or hydraulically communicating subsystems that lubricates a torque converter clutch (TCC)  12  and other components of the transmission  50 . 
     The system  10  includes fluid lines  14 ,  16 ,  18 ,  28 ,  30  and  32 . The fluid line  32  supplies TCC apply fluid  44  to the TCC  12  through a port  13 . And TCC release fluid  43  leaves the TCC  12  through a port  15 . The TCC release fluid  43  may flow as TCC release fluid  40  into the fluid line  28  to an optional valve  24 , or the TCC release fluid  43  may flow as TCC release fluid  42  into the TCC  12  through the fluid line  30 , depending upon the operating conditions of the TCC  12 . In certain conditions, as discussed in detail below, the TCC release fluid  40  flows through the valve  24  into the fluid line  18  as TCC release fluid  36 . The TCC release fluid and the TCC apply fluid can be any suitable hydraulic fluid such as, for example, oil. 
     In a particular arrangement, the valve  24  is a check-ball valve that includes an inlet port  27  and an outlet port  31 . The valve  24  also includes a ball  26  and a biasing mechanism  29 , such as, for example, a coil spring. The biasing mechanism applies a force to the ball  26  towards the inlet port  27 . Hence, if the force on the ball  26  produced by the hydraulic pressure of the TCC release fluid  40  in the fluid line  28  is less than the combined force on the ball  26  produced by the hydraulic pressure of the TCC release fluid  36  in the fluid line  18  and the force produced by the biasing mechanism  29 , the ball  26  is pushed against the inlet  27  to prevent TCC release fluid  36  from flowing back into the fluid line  28 . 
     When the hydraulic pressure of TCC release fluid  40  the fluid line  28  is sufficient to urge the ball  26  away from the inlet port  27 , the TCC release fluid flows through the valve  24  such that the TCC release fluid  36  combines with lubrication fluid  38  from the fluid line  16  in the fluid line  14  as lubrication fluid  34 . The fluid line  14  feeds the lubrication fluid  34  to the remainder of the transmission  50 . The system  10  includes restriction orifices  20  and  22  that control the flow rate of the lubrication fluid  38  and the TCC release fluid  36  in the fluid lines  16  and  18 , respectively. The lubrication fluid  38  can be any suitable hydraulic fluid such as, for example, oil. 
     When in use, the TCC  12  can be in an applied or engaged state or a release or unengaged state. Specifically, when the hydraulic pressure of the TCC apply fluid  44  in the fluid line  32  is or near zero, the TCC  12  is unengaged and the TCC release fluid  43  flows out of the fluid line  30  into the fluid lines  15  and  28 . The TCC release fluid  43  flows past the valve  24  into the fluid line  18  as the TCC release fluid  36 . The TCC release fluid  36  combines with the lubrication fluid  38  from the fluid line  16  as lubrication fluid  34  in the fluid line  14 . The lubrication fluid  34  in the fluid line  14  is then fed into the lubrication circuit associated with other components  50  of the transmission. 
     To engage the TCC  12  to its applied state, pressure of the TCC apply fluid  44  in the fluid line  32  is increased. Any TCC release fluid  43  goes to the fluid line or exhaust outlet  30  as fluid  42 . Hence, the pressure in the fluid line  28  is or near zero. As such, the valve  24  prevents leakage or backflow or TCC release fluid  36  into the fluid line  28 . 
     Turning now to  FIG. 2 , there is shown a flow diagram of process  100  to operate the system  10 . After an initiation step  102 , the process  100  proceeds to a decision step  104 . At the decision step  104 , the process  100  decides whether to engage or un-engage the TCC  12 . If the decision is to engage the TCC  12 , the process  100  proceeds to a step  108  where the pressure of the TCC apply fluid  44  in the fluid line  32  increases such that the TCC  12  is engaged in the step  110 . TCC release fluid  43  and  42  is exhausted from the TCC  12  through the fluid line or exhaust port  30 . 
     If the decision at the step  104  is to un-engage the TCC  12 , the process  100  proceeds to a step  106 . At the step  106 , pressure of the TCC apply fluid  44  in the fluid line  32  is reduced, and TCC release fluid  43  flows into the fluid line  28  as the TCC release fluid  40 . The process  100  proceeds to a step  107  where the TCC  12  is unengaged and the TCC release fluid  40  flows through the valve  24  into the fluid line  18  as TCC release fluid  36 . The TCC release fluid  36  combines with lubrication fluid  38  in the fluid line  14  as lubrication fluid  34 . The combined fluid  34  flows through the fluid line  14  to feed the lubrication circuit for other components  50  of the transmission. 
     After the engage step  110  or the un-engage step  107 , the process  100  returns to the initiation step  102 . 
     The description of the invention is merely exemplary in nature and variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.