Systems and methods for starting an engine that is incorporated into a hybrid vehicle driveline are described. In one example, a torque converter clutch is fully opened if a threshold amount has transpired after a request for torque converter clutch slip is requested but not delivered. Further, the torque converter clutch may be fully opened if a commanded torque converter clutch torque capacity is less than a threshold torque capacity.

Systems and methods for operating various components of a hybrid driveline during starting of an internal combustion engine are described. In one example, output of an electric machine is not adjusted during engine starting when a speed of the electric machine exceeds a threshold speed so that torque reporting is accurate and to ensure combustion is reliable.

A method of operating an accessory drive system for a motor vehicle, wherein the accessory drive system includes one or more accessory components, a motor generator of the motor vehicle, and a flexible drive element configured to transmit a torque load between the one or more accessory components and the motor generator, includes determining a maximum permissible flexible drive element torque threshold, detecting an increase in torque demand on the flexible drive element, determining when the torque demand on the flexible drive element will exceed the flexible drive element torque threshold, and reducing the torque demand of one or more of the accessory components so that the flexible drive element torque threshold is not exceeded.

A vehicle control device controls a vehicle that includes an internal combustion engine, an electric motor, and a drive wheel driven that is capable of starting the internal combustion engine by cranking of the electric motor. When the internal combustion engine is started by cranking of the electric motor, the vehicle control device is configured to: control a power running torque of the electric motor based on an intake pressure of the internal combustion engine until the internal combustion engine goes into a complete combustion state; and control a regenerative torque of the electric motor based on a fuel injection amount of the internal combustion engine until a rotation speed of the internal combustion engine converges within a predetermined range including a target rotation speed, after the internal combustion engine goes into the complete combustion state.

An internal combustion engine (ICE) includes a crankshaft, a cylinder head defining in part a variable combustion chamber of the ICE, a direct fuel injector mounted on the cylinder head, a power source, an electric turning machine (ETM) rotating the crankshaft, an absolute position sensor providing an indication of an angular position of a rotor of the ETM, and an engine control unit (ECU) operatively connected to the absolute position sensor. The ECU controls a delivery of electric power from the power source to the ETM based on the angular position of the rotor of the ETM and causes the direct fuel injector to inject fuel directly in the combustion chamber at a time selected based on the angular position reached by the rotor of the ETM.

A method for controlling delivery of electric power between a power source and an electric turning machine (ETM) comprises applying a start signal to a start-up power electronic switch to cause turning on of the start-up power electronic switch and to allow delivery of electric power from the power source to the ETM via the start-up power electronic switch. A recharge signal is applied to a run-time power electronic switch to cause turning on of the run-time power electronic switch for delivery of electric power from the ETM to the power source via the run-time power electronic switch. A circuit comprises a discharging circuit including the start-up power electronic switch for delivering the electric power when the start-up power electronic switch is turned on. A charging circuit includes the run-time power electronic switch for delivering the electric power when the run-time power electronic switch is turned on.

A method for operating a vehicle that includes a driveline disconnect clutch is described. In one example, the method adjusts torque of an electric machine in response to a estimated torque capacity of the driveline disconnect clutch. The estimated torque capacity of the driveline disconnect clutch is based on a combined inertia of a dual mass flywheel and the driveline disconnect clutch.

A method for operating a vehicle that may be automatically stopped and started is described. In one example, the method includes starting an engine via expansion stroke combustion in response to a request to urgently start the engine. In addition, the method includes adjusting a position of a compression relief valve in response to a predicted urgency of an engine start.

There is provided a hybrid-vehicle controller that can calculate MG demand torque with which fuel consumption in an engine can efficiently be decreased by increasing the MG's power-running torque. In the hybrid-vehicle controller, from a plurality of MG torque candidate values, there are selected the MG torque candidate values that make a 0 MG-torque-reference total supply power variation amount become the same as or smaller than a power-running-side variation amount upper limit value; then, there is selected, as a power-running-side final MG torque candidate value, the MG torque candidate value that makes an absolute value of the relative supply power variation amount ratio become maximum, among the selected MG torque candidate values.

A method for operating a vehicle that may be automatically stopped and started is described. In one example, the method includes supply electrical current to a starter motor independently from supplying electrical current to a starter solenoid. In addition, the method includes adjusting and amount of electrical current that is delivered to the starter motor in response to a level of urgency of an automatic engine start.