Abstract: Methods and systems are provided for limiting requested wheel torque during startup of a vehicle having an electrified powertrain. In one example, a method may include, responsive to a discharge power currently available being less than or equal to a threshold discharge power, operating the vehicle while requesting the wheel torque at a feedforward torque limit, the feedforward torque limit being based on the discharge power and a threshold vehicle speed. In this way, large shifts in wheel torque may be avoided upon startup of the vehicle, thereby reducing noise, vibration, and harshness at the electrified powertrain.

Abstract: Methods and systems are provided for limiting requested wheel torque during startup of a vehicle having an electrified powertrain. In one example, a method may include, responsive to a discharge power currently available being less than or equal to a threshold discharge power, operating the vehicle while requesting the wheel torque at a feedforward torque limit, the feedforward torque limit being based on the discharge power and a threshold vehicle speed. In this way, large shifts in wheel torque may be avoided upon startup of the vehicle, thereby reducing noise, vibration, and harshness at the electrified powertrain.

Abstract: Methods and systems are provided for operating a continuously variable transmission (CVT) of a driveline of a vehicle during a request for engine compression braking. In one example, a method may include, responsive to an engine compression braking request, operating a CVT via a controller to adjust engine speed according to an engine speed-to-vehicle speed profile selected based on a power-based target engine speed for the engine compression braking request. The power-based target engine speed may vary continuously with driver demanded power and a battery charge power limit of the vehicle.

Abstract: Methods and systems are provided for operating a continuously variable transmission (CVT) of a driveline of a vehicle during a request for engine compression braking. In one example, a method may include, responsive to an engine compression braking request, operating a CVT via a controller to adjust engine speed according to an engine speed-to-vehicle speed profile selected based on a power-based target engine speed for the engine compression braking request. The power-based target engine speed may vary continuously with driver demanded power and a battery charge power limit of the vehicle.

Abstract: A method is disclosed for enhancing reverse driving torque in a hybrid electric vehicle powertrain in which an electric motor is used for providing forward driving torque as well as reverse driving torque. An electric generator, functioning as a motor, supplies an added reverse driving torque using a gearset in which the engine provides a reverse driving reaction torque for the gearset.

Abstract: A control method is disclosed for maintaining a calibrated minimum load for an engine in a vehicle powertrain with an engine. The possibility of engine misfire due to low engine loads is reduced. Further, undesired high temperature of an engine exhaust gas catalytic converter due to prolonged operation of the powertrain at low engine loads is avoided.

Abstract: A method is disclosed for enhancing reverse driving torque in a hybrid electric vehicle powertrain in which an electric motor is used for providing forward driving torque as well as reverse driving torque. An electric generator, functioning as a motor, supplies an added reverse driving torque using a gearset in which the engine provides a reverse driving reaction torque for the gearset.

Abstract: A system and method for controlling a vehicle powertrain having an internal combustion engine include determining a difference between a desired engine torque and a current engine torque, adjusting the difference based on a stored torque offset corresponding to a current engine speed, and controlling the engine to produce a torque corresponding to the adjusted torque difference. The stored torque offset is adjusted when the engine is operating in a predetermined engine speed range based on a steady-state difference between the desired and current engine torque to reduce the steady-state difference to zero. The adjusted torque difference may be limited by a maximum-engine-torque-available parameter and a minimum-engine-torque-available parameter, which is based on an operating temperature, such as the engine coolant temperature. The system and method may also include controlling spark to rapidly reduce current engine torque to the adjusted torque difference value.

Abstract: A method is disclosed for controlling an internal combustion engine in a vehicle powertrain. A filtered driver demand for torque at vehicle traction wheels is used to determine an engine torque command. The engine torque command is initialized to a percentage of a target engine torque as a function of variables that may include a smoothness factor.

Abstract: A vehicle and method for controlling an engine in a vehicle are provided. A temperature of a lubricating fluid in the engine is determined, as are first and second engine speed limits. Operation of the engine at the first engine speed limit is limited to a predetermined time period when the lubricating fluid temperature is between first and second predetermined temperatures. The engine speed is at least temporarily limited to the second engine speed limit after the engine has been operated at the first engine speed limit for the predetermined time period and the lubricating fluid temperature is between the first and second predetermined temperatures.

Abstract: A method is disclosed for controlling an internal combustion engine in a vehicle powertrain. A filtered driver demand for torque at vehicle traction wheels is used to determine an engine torque command. The engine torque command is initialized to a percentage of a target engine torque as a function of variables that may include a smoothness factor.

Abstract: A vehicle and method for controlling an engine in a vehicle are provided. A temperature of a lubricating fluid in the engine is determined, as are first and second engine speed limits. Operation of the engine at the first engine speed limit is limited to a predetermined time period when the lubricating fluid temperature is between first and second predetermined temperatures. The engine speed is at least temporarily limited to the second engine speed limit after the engine has been operated at the first engine speed limit for the predetermined time period and the lubricating fluid temperature is between the first and second predetermined temperatures.

Abstract: A control method is disclosed for maintaining a calibrated minimum load for an engine in a vehicle powertrain with an engine. The possibility of engine misfire due to low engine loads is reduced. Further, undesired high temperature of an engine exhaust gas catalytic converter due to prolonged operation of the powertrain at low engine loads is avoided.

Abstract: A vehicle and method are provided that determine a misfire torque limit for an engine in the vehicle. The vehicle includes an electric machine operable to provide torque to the engine. The method includes commanding the engine to operate at a predetermined torque and a predetermined speed, thereby putting the engine in an idle state. An output torque of the engine is then determined while the engine is in the idle state. A torque offset, defined as the difference between the torque command and the determined engine output torque, is also determined. The misfire torque limit for the engine is then determined based at least in part on the torque offset.

Abstract: A vehicle and method are provided that determine a misfire torque limit for an engine in the vehicle. The vehicle includes an electric machine operable to provide torque to the engine. The method includes commanding the engine to operate at a predetermined torque and a predetermined speed, thereby putting the engine in an idle state. An output torque of the engine is then determined while the engine is in the idle state. A torque offset, defined as the difference between the torque command and the determined engine output torque, is also determined. The misfire torque limit for the engine is then determined based at least in part on the torque offset.