Abstract: Systems and methods for reducing driveline mode change busyness for a hybrid vehicle are presented. The systems and methods may delay a driveline mode change in response to a time since a change from a first desired vehicle speed to a second vehicle speed, or alternatively, driveline mode changes may be initiated in response to an estimated time to change from the first desired vehicle speed to the second desired vehicle speed.

Abstract: A hybrid vehicle includes an engine and an electric machine selectively coupled to the engine via a disconnect clutch. At least one controller issues commands to control the engine, the electric machine, and the clutch. During cruise control, the controller controls the torque output of the engine and electric machine, as well as the slipping of the clutch, such that the speed of the vehicle is attempted to be maintained at the cruise control set speed. For example, when the engine is off and additional torque is necessary to maintain the speed, the controller can issue a command to change the state of the engine from off to on. When the vehicle experiences oscillations in road load, the controller delays or inhibits changing the on/off state of the engine for an amount of time that is based on the oscillation associated with road load.

Abstract: A parallel hybrid vehicle includes an engine and a motor separated along a driveshaft by a clutch. The motor can operate (either alone or in combination with the engine) to provide positive drive torque to the wheels. The motor can also act as a generator and provide negative torque when converting mechanical energy from the driveshaft into mechanical energy to be stored in a battery. The clutch selectively couples the motor to the engine. Torque and its effects on the clutch can vary dramatically when the motor changes from providing positive and negative torque, and vice versa, while the engine is running. At least one controller in the vehicle is programmed to, while the engine is running, initiate an increase in pressure at the clutch in response to an anticipated change in torque provided by the motor from positive to negative or from negative to positive.

Abstract: Impeller speed, which is difficult to measure when a torque converter includes an impeller clutch, is estimated based on a known relationship among impeller speed, turbine speed, and turbine torque. Turbine torque may be directly measured by a turbine torque sensor or estimated based on other measurements such as output shaft torque or vehicle acceleration. The relationship is stored in a controller in terms of the coefficients of a second order polynomial relating turbine torque to impeller speed and turbine speed. A slip speed is calculated based on a measured input shaft speed and the estimated impeller speed. Closed loop control is used to adjust the impeller clutch torque capacity to maintain a target slip.

Abstract: A control system including a method and apparatus for operating a hybrid vehicle. A disconnect clutch selectively separates an electric machine from a combustion engine. If a wide open throttle or high torque command is requested and the combustion engine is shut down, a 12 volt starter may be used to start the combustion engine while disconnected from the electric machine and all of the electric machine torque available may be used for traction.

Abstract: Systems and methods for improving transmission gear shifting of a hybrid vehicle are presented. The systems and methods prepare the hybrid vehicle for conditions that may occur after a requested gear shift is performed. In one example, a motor speed that would occur after a downshift, if the downshift were allowed to occur, is determined and control actions may be taken in response to the predicted motor speed.

Abstract: A hybrid electric vehicle having a discrete ratio transmission shifts according to distinct shift schedules in various operating modes. For example, different shift schedules may be used for operating with the engine off, operating with the engine running, and regenerative braking. When the vehicle transitions from one mode to another, the new shift schedule may schedule a shift that the driver would not expect. To avoid annoying the driver, a control strategy inhibits the shift until either the old strategy would also schedule a shift or a customer event occurs.

Abstract: Impeller speed, which is difficult to measure when a torque converter includes an impeller clutch, is estimated based on a known relationship among impeller speed, turbine speed, and turbine torque. Turbine torque may be directly measured by a turbine torque sensor or estimated based on other measurements such as output shaft torque or vehicle acceleration. The relationship is stored in a controller in terms of the coefficients of a second order polynomial relating turbine torque to impeller speed and turbine speed. A slip speed is calculated based on a measured input shaft speed and the estimated impeller speed. Closed loop control is used to adjust the impeller clutch torque capacity to maintain a target slip.

Abstract: Systems and methods for improving transmission shifting of a hybrid vehicle are presented. In one example, output torque of an electric machine is adjusted in response to a downshift of a fixed step ratio transmission during regenerative braking. The output torque of the electric machine may be adjusted in response to a phase of the transmission shift.

Abstract: A hybrid vehicle powertrain is configured to provide a regenerative-braking torque limit on a transmission during a regenerative-braking downshift. The regenerative-braking downshift event has sequential boost, start, torque, inertia, and end phases. The transmission may be operated in absence of a regenerative-braking torque limit during the boost and start phases to recapture more energy. The transmission may be operated with a regenerative-braking torque limit during the torque and inertia phases to protect for an input shaft speed dip that may occur without the limit. The limit may be removed once the regenerative-braking downshift event is completed.

Abstract: In response to a transmission upshift command and a transmission element speed being greater than a threshold, a controller may reduce a rate of engine air intake prior to initial engagement of an oncoming shift element, at least until a target speed ratio is achieved. This reduction may reduce a transmission input torque such that upshift driveline disturbances are reduced.

Abstract: Methods and systems for controlling a vehicle powertrain that may be automatically stopped and started are presented. In one example, a method adjusts a position of a transmission clutch in response to battery current during engine cranking The method may reduce clutch wear and improve vehicle launch from a stop.

Abstract: Methods and systems for controlling a vehicle powertrain that may be automatically stopped and started are presented. In one example, a method adjusts a position of a transmission clutch in response to battery current during engine cranking. The method may reduce clutch wear and improve vehicle launch from a stop.

Abstract: A method of controlling a launch clutch during an engine restart event commands a positive torque capacity before the engine reaches idle speed. Early application of the launch clutch reduces the time delay between brake pedal release and vehicle acceleration. To avoid excessive drag on the engine during the restart event, the torque capacity is adjusted using closed loop control. A controller calculates a maximum rate of change of torque capacity based on measured engine speed and an engine acceleration and does not increase the commanded torque capacity faster than the calculated rate. In some circumstances the maximum rate of change may be negative, resulting in a reduction in commanded torque capacity.

Abstract: A method of controlling a launch clutch during an engine restart event commands a positive torque capacity before the engine reaches idle speed. Early application of the launch clutch reduces the time delay between brake pedal release and vehicle acceleration. To avoid excessive drag on the engine during the restart event, the torque capacity is adjusted using closed loop control. A controller calculates a maximum rate of change of torque capacity based on measured engine speed and an engine acceleration and does not increase the commanded torque capacity faster than the calculated rate. In some circumstances the maximum rate of change may be negative, resulting in a reduction in commanded torque capacity.

Abstract: The present disclosure relates to durability enhancement techniques for a dry-clutch vehicle transmission. A cooling system that provides a direct convective cooling path to friction surfaces is disclosed. Also disclosed is a continuously variable clutch wear compensation assembly configured to adjust the position of clutch assembly components on-demand or as needed.

Abstract: A vehicle system and a method for calculating a vehicle mass is provided. In at least one embodiment, the system and the method measure current consumed by an electric machine of the vehicle to calculate vehicle mass. A controller of the vehicle uses the calculated mass to control operation of the vehicle, for example a four wheel drive, transmission, stability control, or brake system of the vehicle. A GPS and tire speed sensor system may be incorporated to detect the presence of a towed object, for example a trailer, and to further adjust operation of the vehicle.

Abstract: A vehicle includes an engine, an electric machine, a transmission, and at least one controller. The at least one controller, in response to a gear shift of the transmission that causes a speed of the engine to exceed a predetermined speed, commands a change in current to the electric machine such that the speed of the engine decreases to a target speed to avoid engine flare.

Abstract: A system and method for controlling a hybrid vehicle having an engine, a traction motor, and a transmission selectively coupled in series by a clutch include modulating engine torque while the clutch is disengaged and while engine speed is less than motor speed to increase the engine speed. The clutch is engaged to connect the engine to the motor in response to the engine speed exceeding the motor speed.

Abstract: A vehicle system and a method for calculating a vehicle mass is provided. In at least one embodiment, the system and the method measure current consumed by an electric machine of the vehicle to calculate vehicle mass. A controller of the vehicle uses the calculated mass to control operation of the vehicle, for example a four wheel drive, transmission, stability control, or brake system of the vehicle. A GPS and tire speed sensor system may be incorporated to detect the presence of a towed object, for example a trailer, and to further adjust operation of the vehicle.