Internal combustion engine vehicles that employ automatic transmissions typically include a torque converter positioned between the engine and the transmission of the vehicle. A tip-in throttle demand describes a rapid increase in throttle demand or output torque request by the operator. This is done to prevent the TCC feedback (closed loop) control system from increasing the TCC hydraulic pressure as a response to the sudden increase in TCC measured slip. This increase in slip is frequently unavoidable. utilizing a filter to smooth the determined recovery profile. If you have any questions, please call us at (631) 218-8700. Once this initial value is set, a target value to which to reduce slip must be selected. This analysis can be performed experimentally, empirically, predictively, through modeling or other techniques adequate to accurately predict powertrain operation, and a multitude of calibration curves might be developed by the same powertrain for different settings, conditions, or operating ranges. They are bolted to the engine and provide a fluid coupling to the transmission. Method to control torque converter slip in a powertrain including an engine, a transmission, and a torque converter located between the engine and the transmission, the method comprising: detecting a tip-in throttle demand based upon the monitored throttle position sensor; monitoring a measured torque converter slip after the detected tip-in throttle demand; temporarily freezing a pressure command to a torque converter clutch after the tip-in throttle demand; determining a maximum measured torque converter slip value resulting from the tip-in throttle demand based upon the measured torque converter slip; determining a target value for the torque converter slip comprising a desired torque converter slip measured before the tip-in throttle demand; determining a recovery profile to reduce the torque converter slip from the maximum measured torque converter slip to the target value; unfreezing the pressure command to the torque converter clutch; and, utilizing the recovery profile to controllably reduce the torque controller slip; and. Any similar methods known in the art can be utilized to select the mathematical expression for the transition or to manipulate the resulting shape of the profile, and the disclosure is not intended to be limited to the particular embodiments described herein. But how will you figure out if your torque converter is not functioning the way that it’s supposed to? Feedback control is known to control slip in a torque converter through variable control of a TCC. The present disclosure describes an exemplary process for adjusting the torque converter slip in response to changes in engine speed and/or transmission gear and/or engine torque so that the slip is at a desired minimum to conserve fuel, but is not so low where engine pulses and other noise signals are transferred through the torque converter 18 to the driveline 30 and are felt by vehicle occupants. * DENOTES A REQUIRED FIELD AND MUST BE FILLED IN determining a target value for the torque converter slip, determining a recovery profile to reduce the torque converter slip from the maximum measured torque converter slip to the target value, and, wherein the torque converter clutch controls slip reduction within the torque converter; and. As depicted in FIG. The depicted graph illustrates a number of test parameters versus a common timescale through a test period. Other profile shapes besides linear are envisioned including any mathematical expression transitioning from the initial value to the target value, for example including a second, third, or higher order function, defined, for example, by a corresponding quadratic equation, to transition within the recovery profile. Other target values are envisioned, for example, including a time-averaged value of desired torque converter slip before the tip-in throttle demand, a set calibrated torque converter slip value, for example, available in a look-up table based upon engine load and transmission gear, or a historical desired torque converter slip value multiplied by some safety factor, wherein that safety factor can later be switched or phased out to normally controlled steady state torque converter slip values described above. The type of torque converter you choose depends upon how you intend to drive the vehicle. Torque Converter Commanded is 0, but the slip PID is all over the place. Trans >AutoTcc >TCC Desired Slip > TCC Desired Slip AC Off vs. Gear Min Desired Slip AC On Use DoD Slip TCC Desired Slip DoD vs. Gear Desired Slip DoD Off Transition Desired Slip … Navigate to Torque Converter > General. Lag between the commanded torque converter slip values and measured or resulting torque converter slip values, when present, result from the response of the torque converter, the torque converter clutch, and the rest of the related hardware to changing commands. Process 200 differs at 216, wherein terms defining the recovery profile are merged using a first order lag filter, thereby smoothing the recovery profile and the resulting controlled changes to torque converter slip. The TCC desired slip modulated between 40-80 RPM; the TCC actual slip fol-lowed the TCC desired slip within 2-3 Other methods are disclosed, including directly monitoring engine torque, monitoring an air flow mass sensor to estimate engine torque through changes to input air flow, monitoring fuel mass injected into the engine to similarly estimate engine torque through changes in fuel mass injected, and monitoring signals normally sent from the engine to the transmission describing changes in engine torque. When the comparing indicates that the slip has recovered adequately, the process ends at 120. That's how they're able to get rid of the clutch pedal. Meister. The feedforward pressure is designed to be proportional to the estimated engine torque. 110 monitors the measured torque converter slip, analyzing current slip versus a previous slip measurement or analyzing a rate of change in slip, to judge when a maximum torque converter slip value has been reached. Monitoring TPS is one method to identify a rapid increase in engine torque. Other target values are envisioned, for example, including a time-averaged value of desired torque converter slip before the tip-in throttle demand, a set calibrated torque converter slip value, for example, available in a look-up table based upon engine load and transmission gear, or a historical desired torque converter slip value multiplied by some safety factor, wherein that safety factor can later be switched or phased out to normally controlled steady state torque converter slip values described above. Rapid changes in throttle request result in rapid changes to engine speed and torque applied to the torque converter. In one embodiment, in order to avoid the feedback control normally in operation to control slip creating unpredictable changes to slip during a tip-in transition, upon detection of a tip-in throttle demand, a feedback portion of pressure control to the TCC based upon the difference between desired and measured slip is initially frozen during the tip-in throttle demand until the operation of the recovery profile described above. While torque converter slip can be controlled to some small value in steady state operation, rapid and significant increases in NE and TE consistent with tip-in throttle demands are known to result in rapid increases in torque converter slip. until the utilization of the recovery profile, commands the torque converter clutch based upon the feed forward pressure command and the frozen feedback pressure command. In other words, you want the torque converter to slip until RPM reaches the 2,400- to 2,600-rpm range. Prior to transitioning a multiple-displacement engine from a full-displacement engine operating mode to a partial-displacement engine operating mode, a base slip rate of a torque converter coupled to the engine engine is increased by a predetermined slip rate offset. A torque converter clutch control system is provided. In one embodiment, in order to avoid the feedback control normally in operation to control slip creating unpredictable changes to slip during a tip-in transition, upon detection of a tip-in throttle demand, a feedback portion of pressure control to the TCC based upon the difference between desired and measured slip is initially frozen during the tip-in throttle demand until the operation of the recovery profile described above. Exemplary use of the input speed is used in this context as an indirect measure of output speed or vehicle speed. According to one exemplary method, the desired torque converter slip is a function of a transmission gear state, an engine torque, and a turbine or input speed. Torque converters are fascinating. RELEASE BY SECURED PARTY;ASSIGNOR:UAW RETIREE MEDICAL BENEFITS TRUST;REEL/FRAME:025315/0091, Owner name: One or more embodiments will now be described, by way of example, with reference to the accompanying drawings, in which: FIG. 1 (%) Fuel Press Reg. A torque converter is a type of fluid coupling which transfers rotating power from a prime mover, like an internal combustion engine, to a rotating driven load.In a vehicle with an automatic transmission, the torque converter connects the power source to the load.It is usually located between the engine's flexplate and the transmission. No. In this way, feedback control can be utilized to control torque converter slip to a desired value. The torque converter uses hydraulic fluid to transfer rotational energy from the impeller to the turbine. At 116, feedback control of the torque converter to modulate clutch slip according to methods known in the art is enabled. GM GLOBAL TECHNOLOGY OPERATIONS, INC. (Detroit, MI, US). Process 100 is depicted including a plurality of steps and decisions to control torque converter slip.