Abstract: A hybrid vehicle includes an engine, an electric machine, a disconnect clutch configured to selectively couple the engine to the electric machine, and a controller. The controller is programmed to, in response to a request to start the engine with the electric machine, command a target pressure to the disconnect clutch that depends on a seal friction derived from a measured line pressure of the disconnect clutch and a rate change of the measured line pressure.

Abstract: Systems and methods for managing starting of an internal combustion engine during shifting of a transmission of a hybrid vehicle are presented. In one example, torque converter impeller speed or a torque multiplication ratio may be indicative of an unintended transmission downshift during engine starting so that an engine starting device may be switched to improve vehicle operation.

Abstract: Systems and methods for operating a driveline of a hybrid vehicle are presented. In one example, the systems and methods adjust a driveline disconnect clutch boost time duration or magnitude responsive to a pressure error and a time delay error. A driveline disconnect clutch may be operated via supplying a pressure to the driveline disconnect clutch that includes the adjusted boost time duration or magnitude.

Abstract: A hybrid vehicle includes an engine, an electric machine, and a clutch configured to selectively couple the engine to the electric machine. A controller is programmed to command a torque to the electric machine based on a clutch model that includes a learned time constant previously selected using a family of candidate time constants based on a comparison of the family to measured pressure data of a previous engagement of the clutch.

Abstract: A vehicle includes an engine, an electric machine, a disconnect clutch, and a controller. The engine and the electric machine are each configured to generate power. The disconnect clutch is disposed between the engine and the electric machine. The controller is programmed to, in response to a command to start the engine, close the disconnect clutch to transfer power from the electric machine to the engine. The controller is further programmed to control the torque of the disconnect clutch via increasing a pressure applied to the disconnect clutch based on a first-order model of the pressure applied to the disconnect clutch. The controller is further programmed to adjust the model based on a difference between an expected pressure to the disconnect clutch and a measured pressure of the disconnect clutch during a time period prior to transferring torque through the disconnect clutch.

Abstract: Systems and methods for operating a driveline of a hybrid vehicle are presented. In one example, a boost phase of a procedure to close a driveline disconnect clutch may be cut short in response to an engine changing state from not rotating to rotating so that the engine may be restarted in an alternative way. The system and methods may also predict a degraded engine start from a low engine cranking speed or a long cranking time duration so that the engine may be started in an alternative way to increase a possibility of starting the engine and decrease the severity of degraded driveline disturbance.

Abstract: Systems and methods for starting an engine of a hybrid vehicle are described. In one example, the method starts an engine according to vehicle conditions that are within a range that is defined by one or more thresholds. The thresholds may be adjusted based on a history of individual driving patterns.

Abstract: Systems and methods for operating a driveline disconnect clutch of a hybrid vehicle are presented. In one example, a driveline disconnect clutch is positioned according to whether or not there may be slip across the driveline disconnect clutch. In one example, slip may be inferred from vehicle speed and a torque converter impeller speed.

Abstract: A vehicle includes an engine, an electric machine, a disconnect clutch, and a controller. The engine and the electric machine are each configured to generate power. The disconnect clutch is disposed between the engine and the electric machine. The controller is programmed to, in response to a command to start the engine, close the disconnect clutch to transfer power from the electric machine to the engine. The controller is further programmed to control the torque of the disconnect clutch via increasing a pressure applied to the disconnect clutch based on a first-order model of the pressure applied to the disconnect clutch. The controller is further programmed to adjust the model based on a difference between an expected pressure to the disconnect clutch and a measured pressure of the disconnect clutch during a time period prior to transferring torque through the disconnect clutch.

Abstract: Systems and methods for operating a driveline disconnect clutch of a hybrid vehicle are presented. In one example, a driveline disconnect clutch liftoff pressure is estimated according to a derivative of a driveline disconnect clutch pressure when a driveline disconnect clutch is being de-stroked. The driveline disconnect clutch may be prepositioned in anticipation of driveline disconnect closing based on the estimated driveline disconnect clutch liftoff pressure.

Abstract: Systems and methods for operating a driveline disconnect clutch of a hybrid vehicle are presented. In one example, a driveline disconnect clutch is positioned according to whether or not there may be slip across the driveline disconnect clutch. In one example, slip may be inferred from vehicle speed and a torque converter impeller speed.

Abstract: Systems and methods for operating a driveline disconnect clutch of a hybrid vehicle are presented. In one example, a driveline disconnect clutch is de-stroked in a particular way so that the driveline disconnect clutch may be de-stroked more consistently. The de-stroking process may be followed by boosting and stroking the driveline disconnect clutch so as to preposition the driveline disconnect clutch or holding the clutch at an offset below stroke pressure to minimize drag.

Abstract: Systems and methods for operating a driveline disconnect clutch of a hybrid vehicle are presented. In one example, a driveline disconnect clutch liftoff pressure is estimated according to a derivative of a driveline disconnect clutch pressure when a driveline disconnect clutch is being de-stroked. The driveline disconnect clutch may be prepositioned in anticipation of driveline disconnect closing based on the estimated driveline disconnect clutch liftoff pressure.

Abstract: Systems and methods for operating a driveline disconnect clutch of a hybrid vehicle are presented. In one example, a driveline disconnect clutch is de-stroked in a particular way so that the driveline disconnect clutch may be de-stroked more consistently. The de-stroking process may be followed by boosting and stroking the driveline disconnect clutch so as to preposition the driveline disconnect clutch or holding the clutch at an offset below stroke pressure to minimize drag.

Abstract: Systems and methods for selecting and scheduling which of a plurality of engine starting devices starts an internal combustion engine of a hybrid vehicle are presented. In one example, a scheduled start of the internal combustion engine via a driveline disconnect clutch is withdrawn during conditions when both a transmission gear shift is requested or in process and when a driver urgency level is greater than a threshold level.

Abstract: A method includes estimating a first pressure at a first location of a clutch based on a flow rate of a fluid in the clutch, computing a first torque lead value based on the first pressure, computing a second torque lead value based on a second pressure, computing a third torque lead value by combining the first torque lead value and the second torque lead value, and applying torque from a motor of the vehicle based on the third torque lead value.

Abstract: Systems and methods for operating a driveline of a hybrid vehicle are presented. In one example, a boost phase of a procedure to close a driveline disconnect clutch may be cut short in response to an engine changing state from not rotating to rotating so that the engine may be restarted in an alternative way. The system and methods may also predict a degraded engine start from a low engine cranking speed or a long cranking time duration so that the engine may be started in an alternative way to increase a possibility of starting the engine and decrease the severity of degraded driveline disturbance.

Abstract: Systems and methods for starting an engine of a hybrid vehicle are described. In one example, the method starts an engine according to vehicle conditions that are within a range that is defined by one or more thresholds. The thresholds may be adjusted based on a history of individual driving patterns.

Abstract: Systems and methods for operating a driveline of a hybrid vehicle are presented. In one example, a boost phase of a procedure to close a driveline disconnect clutch may be cut short in response to an engine changing state from not rotating to rotating so that the engine may be restarted in an alternative way. The system and methods may also predict a degraded engine start from a low engine cranking speed or a long cranking time duration so that the engine may be started in an alternative way to increase a possibility of starting the engine and decrease the severity of degraded driveline disturbance.

Abstract: Systems and methods for managing starting of an internal combustion engine during shifting of a transmission of a hybrid vehicle are presented. In one example, torque converter impeller speed or a torque multiplication ratio may be indicative of an unintended transmission downshift during engine starting so that an engine starting device may be switched to improve vehicle operation.