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: A vehicle includes an engine, an electric machine, a clutch, and a controller. The clutch is disposed between the engine and the electric machine. The controller is programmed to, in response to an engine start, close the clutch to transfer power from the electric machine to the engine to start the engine. The controller is further programmed to, in response to the engine start, control a torque capacity of the clutch during the engine start according to a model of a pressure applied to the clutch. The controller is further programmed to, in response to the engine start, control the torque of the electric machine based on an adjusted torque capacity of the clutch.

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 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: 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 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: Systems and methods for operating a driveline disconnect clutch of a hybrid vehicle are presented. In one example, torque capacity of a driveline disconnect is adjusted in response to a change in commanded line pressure. The torque capacity of the driveline disconnect clutch may be adjusted in according to a maximum transmission line pressure.

Abstract: Systems and methods for operating a driveline disconnect clutch of a hybrid vehicle are presented. In one example, a time duration of a boost phase of a driveline disconnect clutch closing sequence is adjusted in response to one or more error values. The error values may include pressure error, integrated pressure error, and electric machine speed error.

Abstract: Systems and methods for operating a driveline disconnect clutch of a hybrid vehicle are presented. In one example, the systems and methods may adjust a relationship (e.g., transfer function) between an amount of electric current that is supplied to a driveline disconnect clutch control valve and a commanded driveline disconnect clutch pressure.

Abstract: Systems and methods for operating a driveline disconnect clutch of a hybrid vehicle are presented. In one example, the systems and methods may adjust a relationship (e.g., transfer function) between an amount of electric current that is supplied to a driveline disconnect clutch control valve and a commanded driveline disconnect clutch pressure.

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: Systems and methods for operating a driveline disconnect clutch of a hybrid vehicle are presented. In one example, a driveline disconnect clutch pressure is measured just prior to a request to close the driveline disconnect clutch and a time duration for driveline disconnect clutch boost pressure is adjusted in response to the measured driveline disconnect clutch pressure.

Abstract: A hybrid vehicle includes an electric machine, an engine selectively coupled to the electric machine by a disconnect clutch, and a controller. The controller is programmed to, in response to a change in the driver-demanded torque necessitating starting of the engine: determine a state of driving (SOD) based on the change in driver-demanded torque, wherein the SOD is indicative of a desired responsiveness of the vehicle, and the desired responsiveness increases as SOD increases; command a speed target to the engine equal to a predicted motor speed associated with the driver-demanded torque plus an offset that is based on the SOD; and command a capacity to the disconnect clutch at a rate and a magnitude based on the SOD.

Abstract: A method and system for operating a vehicle that includes a driveline disconnect clutch and a step-ratio transmission is described. In one example, the method includes shifting the step-ratio transmission to neutral and accelerating an engine to an expected input shaft speed of the step-ratio transmission via applying full output capacity of an electric machine to the engine.

Abstract: A vehicle includes an engine having a crankshaft, an electric machine having a rotor, a disconnect clutch having an input secured to the crankshaft and an output secured to the rotor, a hydraulic pump mechanically powered via rotation of the rotor and configured to supply hydraulic fluid to the actuate the disconnect clutch, a torque converter having an impeller secured to the rotor, and controller. The controller is programmed to, responsive to a speed of the impeller decreasing to less than a first threshold, which is indicative of a subsequent shutdown of the hydraulic pump, and responsive to the disconnect clutch being open while the engine is shut down, advance the disconnect clutch to a touch point where opposing sides of disconnect clutch make contact but substantially zero power is transferred between the engine and the electric machine.

Abstract: A method for operating a vehicle that includes a driveline disconnect clutch is described. In one example, the method includes adjusting a pressure of the driveline disconnect clutch as a function of an engine pull-up torque minus a driver demand torque when the pressure of the driveline disconnect clutch is between a torque stroke pressure and a hydraulic stroke pressure.

Abstract: A hybrid vehicle includes an electric machine, an engine selectively coupled to the electric machine by a disconnect clutch, and a controller. The controller is programmed to, in response to a change in the driver-demanded torque necessitating starting of the engine: determine a state of driving (SOD) based on the change in driver-demanded torque, wherein the SOD is indicative of a desired responsiveness of the vehicle, and the desired responsiveness increases as SOD increases; command a speed target to the engine equal to a predicted motor speed associated with the driver-demanded torque plus an offset that is based on the SOD; and command a capacity to the disconnect clutch at a rate and a magnitude based on the SOD.