Abstract: A method for determining the return spring pressure of a clutch in a vehicle transmission includes using proportion-integral-derivative (PID) control logic of a controller to introduce a calibrated error into a pressure command of a holding clutch during a coast-down maneuver of the vehicle. The calibrated error causes a slip level to occur across the holding clutch. The method includes maintaining the slip level using the PID control logic and separately commanding engine torque at different threshold low values during the coast-down maneuver. The pressure/input torque relationship for the holding clutch is recorded for both threshold low levels as the controller continues to maintain the slip. The return spring pressure is calculated using the recorded pressure/input torque relationship. The holding clutch may be controlled a subsequent shift maneuver using the learned return spring pressure. A vehicle is also disclosed having a controller configured to execute steps of the method.

Abstract: Clutch control values are determined via a method in a vehicle during a power-on upshift. Pressure to an offgoing clutch is decreased to a calibrated holding pressure after onset of the upshift. Proportional-integral-derivative (PID) logic of a controller is used to introduce a calibrated error into a pressure command to the offgoing clutch during fill of the oncoming clutch. This causes a calibrated slip to occur across the offgoing clutch, and a resultant threshold amount of flare to occur in turbine speed. The slip and flare are held using the PID logic. The pressure/torque relationship of the offgoing clutch is recorded. A fill level of the oncoming clutch is determined using a trajectory of an integrator term of the PID logic. A control value of the oncoming or the offgoing clutch is adjusted using at least one of the fill level, the recorded clutch pressure, and the recorded clutch torque.

Abstract: A method of learning the return spring pressure of a clutch in a vehicle having an engine and an automatic transmission includes selecting a clutch for analysis from a plurality of clutches of the transmission when the vehicle coasts for a predetermined duration. The method includes ramping down clutch pressure to the selected clutch until engine speed reaches idle and measuring the clutch pressure for the selected clutch after engine speed has remained at idle for a calibrated duration. An actual return spring pressure may be calculated as a function of the preliminary return spring pressure. The actual return spring pressure may be used thereafter to control a subsequent shift event of the transmission. A vehicle includes an engine, transmission, and controller configured to detect a predetermined coasting condition, and to execute code using a processor to thereby execute the above method. A system includes the transmission and controller.

Abstract: Clutch pressure of an oncoming clutch may be determined during an upshift in an automatic transmission by determining when offgoing and oncoming clutches of the transmission near a speed synchronization point. Aboard a vehicle, proportional-integral-derivative (PID) feedback control logic of for the oncoming clutch may be activated via a controller. The controller and the activated PID logic may be used to introduce a calibrated slip error between the rotational speeds of the offgoing and oncoming clutches. Engine speed is then held in a calibrated flare using the PID logic. Oncoming clutch pressure is recorded during the duration of the calibrated flare, and a control action is executed with respect to the transmission using the recorded oncoming clutch pressure, e.g., using recorded PID gains and/or a pressure/torque relationship of the oncoming clutch. A vehicle having an engine, transmission, and controller may use the controller to execute such a method.

Abstract: A method of controlling an offgoing clutch in a transmission during a power downshift includes detecting the downshift, reducing a pressure command to the offgoing clutch, and introducing a calibrated error value to a pressure command for the offgoing clutch during the inertia phase. The method also includes synchronizing the speed of the offgoing and an oncoming clutch during the torque phase, determining the offgoing clutch pressure and torque after synchronizing clutch speeds, and then recording a clutch gain as a function of the offgoing clutch pressure and torque. The recorded clutch gains are used to control a subsequent power downshift of the transmission. A controller using proportional-integral-derivative (PID) control logic introduces the error as PID error in a pressure control signal, and controls slip across the offgoing clutch. A transmission is also disclosed having an offgoing clutch and controller configured to execute the above method.

Abstract: A system for controlling power downshifts of a transmission includes a flare generation module, a flare control module, and a shift control module. The flare generation module generates turbine speed flare by decreasing pressure applied to an off-going clutch of the transmission. The flare control module decreases the turbine speed flare by increasing the pressure applied to the off-going clutch of the transmission. The shift control module increases a pressure applied to an on-coming clutch of the transmission when the turbine speed flare is less than a predetermined amount from a desired turbine speed flare.

Abstract: A method of managing tip-in bump in an automatic transmission includes detecting a set of conditions indicative of an impending throttle tip-in event, including calculating a speed difference between engine speed and turbine speed, and reducing a pressure command to a designated clutch of the transmission to a threshold level. The method also include setting an upper limit on engine torque, flaring the turbine speed during the tip-in event, and using proportional-integral-derivative control logic of a controller to reduce flare to about zero in a calibrated duration, thereby allowing the clutch to dissipate engine inertia and minimize the severity of the tip-in bump. A transmission in a vehicle is operatively connected to an engine and has a torque converter with a turbine. The transmission includes a clutch and a controller configured to manage tip-in bump performance in the transmission via the above method.

Abstract: Clutch pressure of an oncoming clutch may be determined during an upshift in an automatic transmission by determining when offgoing and oncoming clutches of the transmission near a speed synchronization point. Aboard a vehicle, proportional-integral-derivative (PID) feedback control logic of for the oncoming clutch may be activated via a controller. The controller and the activated PID logic may be used to introduce a calibrated slip error between the rotational speeds of the offgoing and oncoming clutches. Engine speed is then held in a calibrated flare using the PID logic. Oncoming clutch pressure is recorded during the duration of the calibrated flare, and a control action is executed with respect to the transmission using the recorded oncoming clutch pressure, e.g., using recorded PID gains and/or a pressure/torque relationship of the oncoming clutch. A vehicle having an engine, transmission, and controller may use the controller to execute such a method.

Abstract: A method of learning the return spring pressure of a clutch in a vehicle having an engine and an automatic transmission includes selecting a clutch for analysis from a plurality of clutches of the transmission when the vehicle coasts for a predetermined duration. The method includes ramping down clutch pressure to the selected clutch until engine speed reaches idle and measuring the clutch pressure for the selected clutch after engine speed has remained at idle for a calibrated duration. An actual return spring pressure may be calculated as a function of the preliminary return spring pressure. The actual return spring pressure may be used thereafter to control a subsequent shift event of the transmission. A vehicle includes an engine, transmission, and controller configured to detect a predetermined coasting condition, and to execute code using a processor to thereby execute the above method. A system includes the transmission and controller.

Abstract: A diagnostic system for a vehicle speed sensor is provided. The system includes: an upshift module that selectively initiates an upshift of a transmission based on a vehicle speed sensor (VSS) signal; a speed drop detection module that monitors at least one of engine speed and input speed for a reduction in speed due to said upshift; and a torque request module that monitors engine torque and selectively diagnoses a VSS malfunction based on said speed reduction and said engine torque.

Abstract: A method of managing tip-in bump in an automatic transmission includes detecting a set of conditions indicative of an impending throttle tip-in event, including calculating a speed difference between engine speed and turbine speed, and reducing a pressure command to a designated clutch of the transmission to a threshold level. The method also include setting an upper limit on engine torque, flaring the turbine speed during the tip-in event, and using proportional-integral-derivative control logic of a controller to reduce flare to about zero in a calibrated duration, thereby allowing the clutch to dissipate engine inertia and minimize the severity of the tip-in bump. A transmission in a vehicle is operatively connected to an engine and has a torque converter with a turbine. The transmission includes a clutch and a controller configured to manage tip-in bump performance in the transmission via the above method.

Abstract: A method of controlling an offgoing clutch in a transmission during a power downshift includes detecting the downshift, reducing a pressure command to the offgoing clutch, and introducing a calibrated error value to a pressure command for the offgoing clutch during the inertia phase. The method also includes synchronizing the speed of the offgoing and an oncoming clutch during the torque phase, determining the offgoing clutch pressure and torque after synchronizing clutch speeds, and then recording a clutch gain as a function of the offgoing clutch pressure and torque. The recorded clutch gains are used to control a subsequent power downshift of the transmission. A controller using proportional-integral-derivative (PID) control logic introduces the error as PID error in a pressure control signal, and controls slip across the offgoing clutch. A transmission is also disclosed having an offgoing clutch and controller configured to execute the above method.

Abstract: Clutch control values are determined via a method in a vehicle during a power-on upshift. Pressure to an offgoing clutch is decreased to a calibrated holding pressure after onset of the upshift. Proportional-integral-derivative (PID) logic of a controller is used to introduce a calibrated error into a pressure command to the offgoing clutch during fill of the oncoming clutch. This causes a calibrated slip to occur across the offgoing clutch, and a resultant threshold amount of flare to occur in turbine speed. The slip and flare are held using the PID logic. The pressure/torque relationship of the offgoing clutch is recorded. A fill level of the oncoming clutch is determined using a trajectory of an integrator term of the PID logic. A control value of the oncoming or the offgoing clutch is adjusted using at least one of the fill level, the recorded clutch pressure, and the recorded clutch torque.

Abstract: A method for determining the return spring pressure of a clutch in a vehicle transmission includes using proportion-integral-derivative (PID) control logic of a controller to introduce a calibrated error into a pressure command of a holding clutch during a coast-down maneuver of the vehicle. The calibrated error causes a slip level to occur across the holding clutch. The method includes maintaining the slip level using the PID control logic and separately commanding engine torque at different threshold low values during the coast-down maneuver. The pressure/input torque relationship for the holding clutch is recorded for both threshold low levels as the controller continues to maintain the slip. The return spring pressure is calculated using the recorded pressure/input torque relationship. The holding clutch may be controlled a subsequent shift maneuver using the learned return spring pressure. A vehicle is also disclosed having a controller configured to execute steps of the method.

Abstract: A method for controlling the torque phase of a clutch-to-clutch power downshift in a vehicle includes determining, during a near-sync boost (NSB) state of the power downshift, a synchronization speed. The method includes estimating, via a controller, a feed-forward clutch pressure that holds a speed of the turbine at the synchronous speed, and then ramping a clutch pressure command to the oncoming clutch to the calculated feed-forward clutch pressure. Closed-loop proportional-integral-derivative (PID) control is initiated over the clutch pressure command during the NSB phase in response to a predetermined PID activation event. A vehicle includes an engine, transmission, torque converter, and a controller. The controller has a processor and memory on which instructions embodying the above method are recorded. Execution of the instructions by the processor causes the controller to execute the method.

Abstract: A method of managing slip in a transmission that is driven by a prime mover includes determining whether a slip condition of the transmission is present based on a slip value and reducing a torque output of the prime mover based on a torque reduction value when the slip condition is present. The method further includes storing the torque reduction value in an array if the slip condition is resolved as a result of the step of reducing and identifying a faulty component within the transmission based on the array.

Abstract: A system for controlling power downshifts of a transmission includes a flare generation module, a flare control module, and a shift control module. The flare generation module generates turbine speed flare by decreasing pressure applied to an off-going clutch of the transmission. The flare control module decreases the turbine speed flare by increasing the pressure applied to the off-going clutch of the transmission. The shift control module increases a pressure applied to an on-coming clutch of the transmission when the turbine speed flare is less than a predetermined amount from a desired turbine speed flare.

Abstract: An engine control system comprises a coasting identification module, a throttle adjustment module, and a fuel adjustment module. The coasting identification module selectively identifies a coasting event. The throttle adjustment module increases an opening of a throttle valve during the coasting event. The fuel adjustment module decreases fuel provided to an engine during the coasting event.

Abstract: A recovery control system and method for automatic transmissions includes a diagnostic module that determines a fault condition of a variable bleed solenoid (VBS) when the automatic transmission fails to establish a desired drive ratio. A recovery module initiates a recovery cycle of the VBS based on the fault condition. The fault condition includes one of a clutch stuck-on condition and a clutch stuck-off condition. A clutch controlled by the VBS fails to disengage during the clutch stuck-on condition, and the clutch fails to engage during the clutch stuck-on condition.

Abstract: A control system is provided. The control system includes a timer module that receives a first torque converter clutch (TCC) apply request and estimates at least one of a message latency time and a hydraulic latency time. A control module receives a subsequent TCC apply request and generates a torque request for an engine based on the at least one of the hydraulic latency time and the torque message latency time.